Research Article | DOI: https://doi.org/10.31579/2640-1053/263
Department of physics with electronics, Federal University Birnin Kebbi.
*Corresponding Author: Samaila B., Department of physics with electronics, Federal University Birnin Kebbi.
Citation: Samaila B., Maidamma B., (2026), Collimator Angle and Its Implications on Treatment Outcomes in Volumetric Modulated Arc Therapy (Vmat): A Systematic Review and Meta-Analysis, J. Cancer Research and Cellular Therapeutics. 10(3); DOI:10.31579/2640-1053/263
Copyright: © 2026, Samaila B. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Received: 14 May 2026 | Accepted: 22 May 2026 | Published: 15 June 2026
Keywords: collimator angle; VMAT; volumetric modulated arc therapy; dosimetric analysis; treatment outcomes; organ-at-risk sparing; cancer therapy
Background: Volumetric Modulated Arc Therapy (VMAT) is an advanced radiotherapy technique that enables highly conformal dose delivery while minimizing radiation exposure to surrounding healthy tissues. The collimator angle is a critical planning parameter that influences beam modulation, dose distribution, and treatment efficiency. However, its quantitative impact on treatment outcomes remains insufficiently defined across different anatomical sites and planning techniques.
Purpose: This study aimed to systematically review and meta-analyze the impact of collimator angle on target coverage, dosimetric parameters, organ-at-risk (OAR) sparing, treatment efficiency, and clinical outcomes in VMAT.
Methods: A systematic review was conducted following PRISMA guidelines, including peer-reviewed studies published. Databases searched included PubMed, Scopus, Web of Science, Embase, and Google Scholar. Studies were included if they evaluated collimator angle effects on VMAT dosimetry, including parameters such as D95, Dmean, conformity index (CI), homogeneity index (HI), monitor units (MUs), and OAR dose. A narrative and thematic meta-analysis was performed.
Results: Across multiple studies, target coverage remained largely stable over a wide range of collimator angles (0°–90°), demonstrating the robustness of VMAT optimization algorithms. However, moderate collimator angles between 15° and 45° consistently produced optimal dosimetric outcomes, including improved CI, HI, and reduced MUs. In prostate VMAT, optimal performance was observed at 20°, 30°, and 45°, while nasopharyngeal carcinoma studies reported improved PTV coverage of approximately 92–94% within the 15°–30° range. Advanced optimization techniques such as SACAO reduced monitor units by approximately 15.7% and field size by 41.1%, significantly improving efficiency and dose conformity. Higher collimator angles (>45°) demonstrated mixed effects, including improved OAR sparing in some cases but reduced delivery accuracy, with γ-index passing rates decreasing by up to 5.6%. Furthermore, collimator misalignment exceeding ±1° resulted in substantial degradation of target coverage and homogeneity, with variations in HI reaching up to 75% in extreme cases. OAR sparing was primarily influenced by multileaf collimator (MLC) design and advanced delivery techniques rather than collimator angle alone. MLC-based shielding reduced OAR dose by up to 20%, while narrower leaf widths (2.5 mm vs 5 mm) improved dose gradients and normal tissue sparing.
Conclusion: Collimator angle has minimal direct impact on target coverage but significantly influences plan quality, efficiency, and treatment robustness. Moderate angles (15°–45°) provide optimal dosimetric performance, while advanced optimization techniques are particularly beneficial in complex cases. Accurate delivery and strict quality assurance are essential, as mechanical errors greater than ±1° can negate dosimetric advantages. Collimator angle should therefore be integrated into a comprehensive, patient-specific VMAT planning strategy.
Volumetric Modulated Arc Therapy (VMAT) is a radiotherapy technique that delivers radiation in a continuous arc while simultaneously modulating the intensity of the radiation beam. It offers several advantages over other techniques. Firstly, VMAT allows for rapid treatment delivery, minimizing the time patients spend on the treatment table. Secondly, it provides better sparing of organs-at-risk (OARs), reducing the radiation dose to healthy tissues surrounding the tumor. Thirdly, VMAT offers improved target coverage, ensuring that the tumor receives the prescribed dose while minimizing the dose to surrounding healthy tissues. Lastly, VMAT has shown to be robust and reproducible, providing consistent treatment outcomes. These advantages have been demonstrated in various studies, including those by Zhang et al. (2023), Hunte et al. (2022), Chen et al. (2020) and Zhang et al. (2022). Volumetric Modulated Arc Therapy (VMAT) is a modern technique used in radiotherapy that offers superior conformity, efficiency, and reproducibility in the treatment of various cancers. It involves delivering radiation in an arc-shaped trajectory while simultaneously modulating the intensity of the radiation beam. VMAT has several advantages over traditional techniques such as Three-Dimensional Conformal Radiotherapy (3DCRT). It has been shown to improve dosimetric measures and treatment outcomes in prostate, cervical carcinoma, and head and neck cancer patients. VMAT has also been found to reduce the mean dose to critical organs such as the bladder and bowel bag in rectal cancer patients, resulting in lower complication probabilities. Additionally, VMAT has been associated with lower radiation doses to the remaining kidney and better coverage of the planning target volume (PTV) in whole abdominal irradiation for Wilms tumor treatment. Overall, VMAT offers improved treatment precision, reduced toxicity, and better treatment outcomes compared to traditional radiotherapy techniques The collimator angle plays a crucial role in VMAT planning. Different collimator angles can affect various dosimetric parameters such as target coverage, conformity index (CI), homogeneity index (HI), gradient index (GI), and monitor units (MUs) (Hashir, et al., 2023; Rose et al.,2023; Jiuling et al., 2022; Wuji et al., 2021). Optimal collimator angles have been found to improve dose conformity, homogeneity, and MUs (Lauren et al., 2021). In nasopharynx carcinoma, collimator angles between 15°-30° have shown better target coverage and reduced MUs . A novel algorithm of sub-arc collimator angle optimization (SACAO) has been developed to improve dosimetric quality and treatment delivery efficiency in single-isocenter coplanar VMAT stereotactic radiosurgery (SRS) for multiple metastases. For whole-brain radiotherapy with hippocampus and inner ear sparing, increasing the collimator angle towards 90° has shown significant improvements in plan quality, including better CI, HI, and reduced doses to organs-at-risk . However, collimator angle optimization may have limited benefit in reducing island blocking in single-isocenter multiple-target (SIMT) SRS plans. Understanding the impact of collimator angle on treatment outcomes is important in radiation therapy. Different collimator angles can affect the surface dose, dose conformity, homogeneity, and dose to organs at risk (OARs) (Jeong-Ho et al., 2022; Hashir et al., 2022; Jiuling et al., 2022; Yong et al., 2017). Studies have shown that the surface dose increases as the collimator angle increases, and the length of the tumor also affects the surface dose. Optimal collimator angles have been found to improve dose conformity, homogeneity, and treatment efficiency. Additionally, collimator angle optimization can lead to better target dose distribution and sparing of OARs. The choice of collimator angle can impact dosimetric parameters such as target coverage, CI, HI, GI, and MUs. Therefore, understanding the impact of collimator angle is crucial for optimizing treatment plans and achieving better treatment outcomes in radiation therapy. The optimal collimator angle in radiation therapy has been a topic of controversy. Several studies have investigated the impact of collimator angle on treatment plan quality and organ-at-risk sparing. Battinelli et al. found that optimizing the collimator angle can reduce the exposed area between lesions in non-isocentric treatments, leading to more efficient treatment and potential time savings (Cecilia et al., 2021). Sun et al. demonstrated that increasing the intersection angle between collimator angles in dual-arc VMAT plans for whole-brain radiotherapy can improve plan quality, including conformity and homogeneity indices, as well as reduce monitor units and dose to organs-at-risk (Wuji et al., 2021). Saeed et al. concluded that different collimator angles have minimal impact on target coverage and dose to organs-at-risk in prostate carcinoma patients, suggesting the need for solid decision-making regarding collimator angles (Hashir et al., 2023). Mancosu et al. highlighted the significance of collimator angle rotation in optimizing dose distribution for vertebral metastases, with leaf travel parallel to the spinal cord primary orientation yielding the best plans (Pietro et al., 2010). Andersen et al. recommended maintaining collimator angles within 15-30 degrees based on various dosimetric parameters and quality assurance results (Andersen et al., 2016). The main objective of the paper is to systematically evaluate the available literature on the impact of collimator angle on treatment outcomes in VMAT. To assess the influence of collimator angle on dose distribution to the target and critical organs and to identify the optimal collimator angle for various treatment scenarios and potential recommendations for clinical practice.
Study Design and Search Strategy
This study followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to conduct a systematic review on the impact of collimator angles on treatment outcomes in Volumetric Modulated Arc Therapy (VMAT). A comprehensive literature search was performed in major databases, including PubMed, Scopus, Web of Science, Embase, and Google Scholar, from their inception to January 2025. The search terms included: Collimator angle, Volumetric Modulated Arc Therapy" OR "VMAT, Treatment outcomes, Dosimetric impact and Radiotherapy planning. Boolean operators (AND, OR) were applied to refine search queries and retrieve relevant studies. Additional hand-searching of the reference lists of included articles was conducted to ensure comprehensive coverage.
Inclusion and exclusion Criteria
| Criteria | Inclusion | Exclusion |
| Study Type | Peer-reviewed articles. | Reviews, case reports, editorials, conference abstracts. |
| Studies with quantitative analyses on collimator angles in VMAT. | Studies using treatment modalities other than VMAT (e.g., IMRT, 3D-CRT). | |
| Language | English-language studies. | Non-English language studies. |
| Tumor Sites | Studies on various tumor sites (e.g., head and neck, prostate, lung, etc.). | Studies not specifying tumor site or focusing on non-cancerous conditions. |
| Outcome Measures | Studies reporting dosimetric parameters, including PTV coverage, OAR sparing, homogeneity index, etc. | Studies without specific or relevant dosimetric outcomes related to collimator angles. |
| Collimator Angle Focus | Studies analyzing or comparing the impact of different collimator angles in VMAT. | Studies not addressing collimator angle configuration. |
| Publication Year | Published between January 2000 and January 2025. | Outside the specified date range. |
| Population | Studies involving human patients or anthropomorphic phantom models. | Preclinical studies using animals or computational-only models without patient validation. |
Data extraction and Synthesis
Data extraction was performed using a standardized form that comprised of Title, Objective, Methods Used, Results, Conclusions, Contributions, Practical Implications and References. Any discrepancies in data extraction were resolved through discussion and consensus among the reviewers. A narrative synthesis approach was employed to summarize and interpret the findings from the selected studies (Samaila et al., 2024; Samaila et al., 2025).
Ethical Considerations
This review exclusively involved the narrative analysis of published data, and therefore, ethical approval was not required.
Numerous studies have explored the impact of collimator angles on dose distribution to target volumes and critical organs. Findings indicate that the optimal collimator angle varies significantly depending on the specific treatment site and technique. In prostate cancer patients, collimator angles of 20°, 30°, and 45° have demonstrated superior dose conformity, homogeneity, and monitor unit (MU) efficiency. For nasopharyngeal carcinoma, collimator angles within the 15° to 30° range have been shown to enhance target coverage while reducing MU usage. In the context of stereotactic body radiotherapy (SBRT) for non-small cell lung cancer, MLC positional errors, including collimator angle deviations, can significantly impact dose distribution, with VMAT being more susceptible than IMRT. For single-isocenter coplanar VMAT stereotactic radiosurgery of multiple brain metastases, a novel algorithm known as Sub-Arc Collimator Angle Optimization (SACAO) has been shown to improve dosimetric quality and treatment delivery efficiency. The selection of collimator angles in VMAT should be carefully evaluated for each treatment scenario to optimize plan quality, target coverage, and treatment efficiency.
Impact of collimator angle on Target Coverage
The studies summarized in Table 1 collectively demonstrate that collimator angle has a limited influence on baseline target coverage but plays a significant role in optimizing overall plan quality in volumetric modulated arc therapy (VMAT). In prostate cancer planning, both Saeed et al. (2023) and Isa et al. (2014) consistently reported that planning target volume (PTV) coverage remains largely unchanged across a wide range of collimator angles (0°–90°). This finding suggests that modern inverse planning algorithms are sufficiently robust to maintain clinically acceptable coverage regardless of collimator orientation. However, while coverage remains stable, key dosimetric parameters such as conformity index (CI), homogeneity index (HI), and monitor units (MUs) are sensitive to angle selection, indicating that collimator angle primarily influences plan quality refinement rather than fundamental dose delivery. A consistent trend across multiple studies and anatomical sites is that moderate non-zero collimator angles, typically within the range of 15° to 45°, provide the most favorable dosimetric outcomes. Saeed et al. (2023) identified optimal plan performance at 20°–45°, while Isa et al. (2014) reported improved conformity and homogeneity at 45°. Similarly, Thomas et al. (2023) demonstrated that angles between 15° and 30° achieved superior PTV coverage and reduced monitor units in nasopharyngeal carcinoma, whereas very low angles (5°–10°) resulted in poorer coverage. These improvements are likely attributable to enhanced multileaf collimator (MLC) modulation and reduced tongue-and-groove effects, which enable more effective dose shaping. Consequently, moderate collimator angles appear to provide an optimal balance between dosimetric quality and delivery efficiency and may serve as a practical default in routine VMAT planning. Despite these advantages, important trade-offs related to deliverability, mechanical accuracy, and case complexity must be considered. Kim et al. (2015) reported a negative correlation between collimator angle and gamma index passing rates, suggesting that higher angles may compromise delivery accuracy. Furthermore, Puchades-Puchades et al. (2015) demonstrated that collimator angle misalignment exceeding ±1° can significantly degrade target coverage and homogeneity, particularly for large PTVs, highlighting the importance of rigorous quality assurance and precise mechanical calibration. In complex clinical scenarios, such as craniospinal irradiation and stereotactic radiosurgery, collimator angle assumes a more critical role. Li et al. (2015) showed that non-zero angles eliminate dose gaps at field junctions, while Battinelli et al. (2021) demonstrated that sub-arc collimator angle optimization significantly improves plan quality and efficiency. These findings underscore the need for individualized, context-specific collimator angle selection that balances dosimetric benefits with delivery feasibility.
| Title | Objective | Methods Used | Results | Conclusions | Contributions | Practical Implications | References |
| The Effect of Varying Collimator Angles on VMAT Planning of Prostate Cancer | To investigate how different collimator angles affect VMAT plan quality for prostate cancer | VMAT plans optimized with 1.5 arcs at collimator angles of 0°, 10°, 20°, 30°, 45°, 90°; dose calculated with AAA (Anisotropic Analytical Algorithm) | Found optimal performance (conformity, homogeneity, MUs) at 20°, 30°, 45°. Target coverage and OAR doses were not significantly different across angles. | Optimal collimator angles (20°–45°) improve plan quality; choice of angle is important for conformity/homogeneity | Clarifies which angles yield best trade-off among plan metrics | Guides clinical medical physicists in collimator angle selection | Saeed et al., (2023) |
| Dosimetric Dependence on the Collimator Angle in Prostate VMAT | To quantify dose-volume changes (PTV and OARs) in prostate VMAT as a function of collimator angle | Single-arc VMAT plans on a phantom at collimator angles 0°, 15°, 30°, 45°, 60°, 75°, 90°; dose‑volume analyses for PTV and OARs (bladder, rectum, femoral heads) | No large differences in PTV coverage across angles. The 45° angle gave a higher conformity index (~0.53) and lower homogeneity index (~0.064). Some angles (75°, 90°) favored OAR sparing. | Clinical physicists can use collimator angle tuning to optimize plan quality without compromising coverage | Provides systematic data linking collimator angle and plan metrics for prostate VMAT | Supports more evidence-based angle selection in VMAT planning | Isa et al., 2014 |
| A Dosimetric Study on the Impact of Collimator Angles in Nasopharyngeal Carcinoma (NPC) Using VMAT | To determine the best collimator angle for NPC VMAT planning using Monte Carlo algorithm | Retrospective study of 29 NPC patients; dual-arc VMAT in Monaco TPS using Monte Carlo, evaluating angles 0°–45° (in steps) | Collimator angles between 15°–30° gave better PTV coverage (∼92–94%) and significantly reduced monitor units. Very low angles (5°–10°) had poor coverage; 45° produced highest MUs. | Collimator angles in the 15–30° range are optimal for NPC VMAT in this setting | Adds specific guidance for head-and-neck cancer planning | Helps clinical teams select angle to balance tumor coverage and efficiency | Thomas et al. (2023) |
| The Importance of Collimator Angle Error in VMAT | To assess how errors in setting collimator angle (mis-calibration) affect dosimetry | Simulated collimator errors (±0.5°, ±1°, ±1.5°) on VMAT plans for different PTVs (prostate, head & neck, etc.); recalculated dose; compared DVHs and HI | For large PTVs (e.g., prostate), errors > ±1° caused large loss of PTV coverage; homogeneity index relative variation up to 75% in worst case. | Collimator misalignment can severely degrade plan quality, especially for large targets | Emphasizes need for strict QA of collimator calibration | Suggests using isocenter near PTV center to reduce sensitivity | Puchades-Puchades et al., 2015 |
| Sub-Arc Collimator Angle Optimization (SACAO) for Multiple Brain Metastases in VMAT SRS | To improve plan quality (CI, HI, gradient) and efficiency (MU, field size) for VMAT SRS of multiple brain mets via optimized sub-arcs | Developed and applied an automated SACAO algorithm based on heatmaps of MLC blocking index; compared SACAO plans vs fixed-collimator full-arc plans | SACAO improved CI, HI, gradient index, and reduced MU by ~15.7%, field size by ~41.1%. Also better sparing of normal brain, brainstem, eyes. | Introduces a practical, automated method for choosing collimator angles sub-arc by sub-arc to boost plan quality and efficiency | Strong contribution in algorithmic planning for SRS | Suggests that using SACAO can reduce delivery time and improve sparing for multi-target SRS | Battinelli et al., 2021 |
| Collimator Rotation in VMAT for Craniospinal Irradiation (CSI) | To assess how rotating the collimator influences dose uniformity and beam overlap in multi-isocenter VMAT for CSI | VMAT plans with two isocenters, testing collimator angles of 0°, 30°, 45° for upper and lower arcs; phantom and patient DVH; experimental validation with film and ion‑chamber | No significant differences in HI and CI among some angles, but plans with 45° collimator required more MUs and segments; importantly, non-zero angle (≥5°) eliminated a 1 mm low-dose gap at the junction. | Rotating the collimator off 0° (e.g., 45°) helps avoid dose gaps at beam junctions without compromising coverage | Offers practical evidence for junction management in multi-isocenter VMAT | Suggests that using non-zero collimator angles improves plan robustness in craniospinal VMAT | Li, et al. 2015 |
| Effect of Collimator Angle on Dosimetric Verification of VMAT (Head & Neck) | To evaluate how collimator angle influences the accuracy of dose delivery (γ‑index) in QA | For 10 head‑and‑neck patients, generated VMAT plans at collimator angles from 0° to 45° (in 5° increments), verified with 2D ion chamber array (MatriXX) and γ-index (2%/2 mm, 3%/3 mm) | γ‑index passing rates showed a negative correlation with collimator angle: higher angles tended to yield lower passing rates (i.e., less accurate delivery). Maximum per-patient differences up to ~5.6%. | Accuracy of VMAT delivery (via QA) depends on collimator angle | Warns planners about potential trade-offs between plan quality and deliverability for higher collimator angles | Important for clinical physicists: when using high collimator angles, must check QA to ensure acceptable delivery | Kim et al. 2015 |
Table 1: Impact of collimator angle on Target Coverage.
Organ at risk (OAR) sparing
The studies presented in Table 3 demonstrate that advanced collimation techniques, particularly the use of multileaf collimators (MLCs), play a crucial role in reducing radiation dose to organs at risk (OARs) across a range of clinical applications. In breast cancer radiotherapy, significant reductions in mean dose to critical structures such as the heart, left anterior descending artery (LAD), and lungs were achieved through MLC-based shielding (Mahani et al., 2023). Similarly, MLC-shielded fields have been shown to reduce out-of-field doses compared to conventional cerrobend blocks, indicating improved protection of healthy tissues during treatment (Momeni, 2023). These findings highlight the importance of precise beam shaping in minimizing unintended radiation exposure while maintaining effective target irradiation. Beyond the presence of MLCs, their configuration and integration with advanced treatment techniques further enhance OAR sparing. Narrower MLC leaf widths have been associated with improved conformity and steeper dose gradients, resulting in superior normal tissue sparing, particularly in stereotactic irradiation for brain metastases (Ohira et al., 2021). Additionally, technique-driven innovations such as 90° angled collimated dynamic IMRT (A-IMRT) demonstrated improved OAR protection compared to conventional IMRT, although volumetric modulated arc therapy (VMAT) remained superior overall in terms of conformity and sparing (Serarslan et al., 2023). Furthermore, dynamic trajectory radiotherapy (DTRT), which incorporates coordinated motion of the gantry, couch, and collimator, achieved substantial improvements in OAR sparing in head and neck cancers compared to VMAT (Bertholet et al., 2022). These findings suggest that both hardware characteristics and delivery techniques are critical determinants of optimal organ protection. Optimization strategies involving collimator orientation and beam geometry also contribute to achieving a balance between target coverage and OAR sparing. While variations in collimator angle alone may not significantly influence OAR dose in certain cases, such as prostate VMAT (Saeed et al., 2023), more advanced approaches can yield meaningful improvements. For example, the split X-jaw technique has been shown to enhance target coverage while simultaneously reducing dose to surrounding normal tissues (Sarma et al., 2023). Collectively, the evidence indicates that effective OAR sparing is achieved through a combination of appropriate collimator design, optimized beam modulation, and advanced planning strategies. These findings underscore the need for individualized, technique-specific planning approaches to maximize the therapeutic ratio in modern radiotherapy.
| Title of the paper | Objective | Methods Used | Results | Conclusions | Contributions | Practical Implications | Ref |
| The Efficacy of Multi-Leaf Collimator in the Reduction of Cardiac and Coronary Artery Dose in Left-Sided Breast Cancer Radiotherapy | To evaluate the effect of multi-leaf collimators on the protection of sensitive organs in patients with left breast cancer, including the left anterior descending artery (LAD) and the left lung. | Evaluation of protective effect of multi-leaf collimator (MLC) Comparison of dosimetric results for tumor and organs at risk (OARs) | MLC coverage leads to significant reduction in mean dose of OARs. Better protection of LAD, heart, and lungs achieved with MLC shielding. | MLC can effectively reduce cardiac and coronary artery dose in left-sided breast cancer radiotherapy. Better protection of LAD, heart, and lungs can be achieved with MLC. | Evaluation of the protective effect of multi-leaf collimator (MLC) in left breast cancer radiotherapy. Reduction in mean dose and volume received by organs at risk (OARs). | Multi-leaf collimator (MLC) can effectively reduce cardiac and coronary artery dose in left-sided breast cancer radiotherapy.MLC can provide better protection for sensitive organs at risk. | Mahani et al., 2023 |
| Ninety-degree angled collimator: a dosimetric study related to dynamic intensity-modulated radiotherapy in patients with endometrial carcinoma | Develop a new IMRT technique named 90° angled collimated dynamicIMRT (A-IMRT) planning to ensure that the dose constraints of the organs at risk (OARs) were not exceeded while increasing the prescription dose to the planning target volume (PTV) from 45 to 50. | Conventional dynamic IMRT (C-IMRT) with collimator angle of 0° at all gantry angles 90° angled collimated dynamic IMRT (A-IMRT) with collimator angle of 90° at specific gantry angles (110°, 180°, 215°, and 285°) Volumetric modulated arc therapy (VMAT) | A new dynamic IMRT technique called 90° angled collimated dynamic IMRT (A-IMRT) planning was developed.A-IMRT protected organs at risk (OARs) better than conventional dynamic IMRT (C-IMRT). | VMAT achieved superior organ at risk (OAR) protection and conformity compared to A-IMRT and C-IMRT. OARs are better protected with 90° angled collimated dynamic IMRT technique. | Development of a new dynamic IMRT technique called 90° angled collimated dynamic IMRT (A-IMRT) planning. Comparison of A-IMRT with conventional dynamic IMRT (C-IMRT) and volumetric modulated arc therapy (VMAT) techniques. | The 90° angled collimated dynamic IMRT technique can protect organs at risk better than conventional IMRT. VMAT achieved superior organ at risk protection compared to A-IMRT and C-IMRT. | Serarslan et al., 2023 |
| The Effect of Varying Collimator Angles on VMAT planning of Prostate Cancer | The paper focuses on dose-volume evaluation in the planning target volume (PTV) and organs-at-risk (OARs) in prostate carcinoma patients. | VMAT plans were optimized with different collimator angles (0°, 10°, 20°, 30°, 45°, 90°) Dosimetric analysis was performed using Anisotropic Analytical Algorithm (AAA) Version 15.6.04 | Optimal collimator angles for VMAT planning are 20°, 30°, and 45°. Target coverage and dose to organs at risk are not significantly affected. | Optimal collimator angles are necessary for better conformity and homogeneity. Target coverage and dose to organs at risk are not significantly affected by collimator angles. | Investigated the effect of varying collimator angles on VMAT planning for prostate cancer Analyzed dose-volume evaluation in planning target volume and organs-at-risk | Clinical medical physicists should consider the collimator angle for treatment planning. Optimal collimator angles can improve conformity and homogeneity in VMAT planning. | Saeed et al., 2023 |
| Organ-at-risk sparing with dynamic trajectory radiotherapy for head and neck cancer: comparison with volumetric arc therapy on a publicly available library of cases | To Compare the performance of DTRT and VMAT for common head and neck (HN) cancer cases on a C-arm linac with high accuracy. | Dynamic trajectory radiotherapy (DTRT) with dynamic table and collimator rotation Volumetric modulated arc therapy (VMAT) for comparison | DTRT plans showed similar target coverage compared to VMAT. DTRT resulted in substantial sparing of organs-at-risk (OARs) compared to VMAT. | DTRT showed substantial improvement in OAR sparing for HN cancer radiotherapy compared to VMAT. Plans were deliverable on standard linacs with good agreement between calculated and measured dose. | The paper establishes dynamic trajectory radiotherapy (DTRT) as a viable treatment option for head and neck cancer. DTRT plans showed substantial organ-at-risk (OAR) sparing compared to volumetric modulated arc therapy (VMAT). | Substantial improvement in OAR sparing for HN cancer radiotherapy using DTRT compared to VMAT. Plans are deliverable on standard linacs and can be applied to similar cases in future clinical studies. | Bertholet,et al., 2022 |
| Impact of Multileaf Collimator Width on Dose Distribution in HyperArc Fractionated Stereotactic Irradiation for Multiple (-) Brain Metastases. | To evaluate Impact of Multileaf Collimator Width on Dose Distribution in HyperArc Fractionated Stereotactic Irradiation for Multiple (-) Brain Metastases. | Two types of multileaf collimators (MLC) were used: high definition (HD) MLC (2.5 mm) and Millennium (ML) MLC (5 mm). Dosimetric parameters between the planning target volume (PTV) and organs at risk (OARs) were compared. | HyperArc plans with narrower MLC had higher conformity and steeper dose gradient. Narrower MLC resulted in better normal tissue sparing. | Narrower multileaf collimator (MLC) provides higher conformity, steeper dose gradient, and better normal tissue sparing. High definition (HD) MLC (2.5 mm) is more effective than Millennium (ML) MLC (5 mm). | The paper assesses the impact of multileaf collimator (MLC) width on dose distributions in HyperArc fractionated stereotactic irradiation for multiple brain metastases. The narrower MLC provided higher conformity, steeper dose gradient, and better normal tissue sparing. | Narrower multileaf collimator (MLC) improves conformity, dose gradient, and tissue sparing. HyperArc fractionated stereotactic irradiation with narrower MLC is beneficial for multiple brain metastases. | Ohira et al., 2021 |
| The Estimation of Radiation Dose to Out-of-Field Points of Organs at Risk in Block and MLC Shielded Fields in Lung Cancer Radiation Therapy | measured and compare the healthy organs absorbed dose outside the cerrobend block and MLC shielded field and showed that the use of MLC to shield the lung cancer treatment filed reduces the out-of-field OARs dose compared to cerrobending block. | Computed Tomography (CT) imaging of a heterogeneous Thorax phantom Conformal Treatment planning on the Prowess Panter Treatment Planning System (TPS) | Out-of-field dose in MLC-shielded fields is significantly lower than in block-shielded fields. Healthy organs absorbed doses were significantly lower than dosimetry results. | MLC shielding reduces out-of-field OAR dose compared to cerrobend block. Reduction is greater at 18 MV photon beam but not statistically significant. | Comparison of absorbed dose to out-of-field organs in block and MLC shielded fields Reduction of out-of-field organ dose with MLC shielding in lung cancer radiation therapy | The use of MLC shielding reduces out-of-field organ dose in lung cancer radiation therapy. The reduction in dose is greater with 18 MV photon beam. | Momeni., 2023 |
| Impact of split X-jaw technique on target volume coverage and organ at risk sparing in prostate cancer: a comparative dosimetric study | To use a split X-jaw planning technique was used for volumetric-modulated arc radiotherapy (VMAT) for PTVs requiring a field size larger than 18 cm in the Xjaw position in the Varian Trilogy linear accelerator. | Open, limited, and split X-jaw planning techniques were used. Computed tomography data sets from 15 prostate cancer patients were used. | Split X-jaw technique improves target dose coverage in prostate cancer patients. Split technique delivers lower dose to organs at risk. | Split X-jaw technique improves target dose coverage in prostate cancer patients. Split technique delivers lower dose to organs at risk. | The paper investigates the impact of the split X-jaw technique on target volume coverage and organ at risk sparing in prostate cancer patients. The study concludes that the split X-jaw technique improves plan quality in terms of target dose coverage for PTVs requiring a field size larger than 15 cm in the X-jaw direction. | The split X-jaw technique improves target dose coverage in prostate cancer patients. The split technique delivers a lower dose to organs at risk. | Sarma et al., 2023 |
| Dosimetric impact of different multileaf collimators on cardiac and left anterior descending coronary artery dose reduction. | To evaluate Dosimetric impact of different multileaf collimators on cardiac and left anterior descending coronary artery dose reduction | Three techniques were used to create treatment plans for patients. Two different multileaf collimators (MLCs) with different leaf widths were used. | Covered LAD plan 1 (CL1) reduced lung, cardiac, and LAD doses. CL1 plans decreased mean heart dose from 6.2 Gy to 5.4 Gy. | CL1 plans reduce OAR dose without compromising target coverage. Proper implementation of MLC can decrease side effects of RT. | Evaluation of the impact of different multileaf collimators (MLCs) on shielding organ at risks (OARs), especially the left anterior descending coronary artery (LAD), in patients with left breast cancer. Comparison of dosimetric parameters of the heart, LAD, and ipsilateral lung for different MLC plans. | The use of specific multileaf collimators can reduce the dose to organs at risk in left breast cancer patients undergoing radiotherapy. Implementing proper MLC techniques can decrease side effects of radiotherapy. | Mahani,et al., 2023 |
Table 3: organ at risks.
Impact of collimator angle on Clinical outcomes
The reviewed literature in table 4 demonstrates that collimator angle optimization has a measurable and clinically relevant impact on treatment quality in VMAT and SRS planning, with the degree of influence varying across anatomical sites and planning techniques. In prostate VMAT planning, Saeed et al. (2023) reported that while target coverage and organ-at-risk (OAR) doses remained largely unchanged, optimal angles between 20° and 45° significantly enhanced dose conformity and homogeneity, emphasizing that collimator settings primarily refine dose distribution rather than altering overall plan safety. In cases involving multiple brain metastases, the influence of collimator angle selection becomes more pronounced. Shen et al. (2022) showed that the Sub-Arc Collimator Angle Optimization (SACAO) algorithm greatly improved conformity, homogeneity, and gradient indices while reducing monitor units and field size by more than 40%, thereby improving treatment efficiency. Supporting this, Battinelli et al. (2021) demonstrated that dynamic collimator trajectories outperform fixed angles, achieving exposed-area reductions of up to 71%, which can substantially improve lesion selectivity and reduce unnecessary normal-tissue irradiation. Other studies presented more nuanced perspectives based on planning context and disease site. Pudsey et al. (2021) found that collimator angle optimization and jaw tracking provided limited clinical benefit in single-isocenter, multiple-target SRS, suggesting that geometric complexity can overshadow the effects of angle adjustment. In whole-brain radiotherapy with hippocampal and cochlear sparing, Sun et al. (2021) reported that increasing the angular separation between dual-arc collimator configurations improved plan quality and reduced monitor units, highlighting angle selection as a modifiable parameter for complex sparing scenarios. For locally advanced nasopharyngeal carcinoma, Kim et al. (2017) found that angles of 20°–30° produced the best conformity and homogeneity indices, although higher angles were associated with increased optic-apparatus dose, demonstrating the need for balanced optimization. Foundational contributions by Zhang et al. (2010) and Kim et al. (2015) further showed that personalized and dynamically optimized collimator strategies can enhance dosimetric performance while improving quality-assurance γ-index outcomes. Collectively, these studies establish that collimator angle optimization is integral to maximizing plan conformity, improving treatment efficiency, minimizing unnecessary exposure, and strengthening overall VMAT plan quality.
| Paper title | Objective | Method | Result | Conclusion | Contribution | Ref |
| The Effect of Varying Collimator Angles on VMAT planning of Prostate Cancer | To assess the effect of different Angle | Dosimetric analysis was performed using Anisotropic Analytical Algorithm (AAA) Version 15.6.04 | VMAT plans were optimized with different collimator angles (0°, 10°, 20°, 30°, 45°, 90°). Optimal collimator angles for VMAT planning were achieved at 20°, 30°, and 45°. | Target coverage and dose to organs at risk are not significantly affected. | Clinical medical physicists should consider the collimator angle for treatment planning. Optimal collimator angles can improve conformity and homogeneity in VMAT planning. | Saeed al., 2023 |
| Sub-arc collimator angle optimization based on the conformity index heatmap for VMAT planning of multiple brain metastases SRS treatments | The SACAO method could be superior in improving the CI, HI, and GI of the targets as well as normal tissue sparing for multiple brain metastases SRS and has the potential of increasing treatment efficiency in terms of field size and MU. | SACAO method improves dosimetric quality and treatment efficiency for multiple brain metastases SRS. SACAO reduces field size and monitoring units by 41.11%. | The SACAO method improved conformity index, homogeneity index, and gradient index. SACAO reduced field size and monitoring units by 41.11%. | Sub-arc collimator angle optimization (SACAO) algorithm Calculation of multi-leaf collimator (MLC) conformity index (MCI) | Investigated impact of collimator angle optimization in VMAT SRS for multiple brain metastases Developed a novel algorithm for sub-arc collimator angle optimization (SACAO) | Shen, al., 2022 |
| Technical Note: Collimator angle optimization for multiple brain metastases in dynamic conformal arc treatment planning. | - | Collimator angle optimization reduces exposed area between brain metastases in treatment planning. Dynamic collimator trajectories are more effective than fixed trajectories in reducing exposed area. | Plans with optimized dynamic collimator trajectories showed a reduction in exposed area between lesions ranging from 21.7% to 71.3%. Beam-wise reductions in exposed area ranged from 5.83% to over 90%. | An algorithm that estimates the quality of an arc by considering the target projections onto the plane perpendicular to the central axis of the arc beam. The algorithm can generate two outputs: the fixed optimal collimator angle over all the control points, or the optimal collimator angle trajectory through all the control points considering the rotation speed of the collimator. | Development of an algorithm for optimizing collimator angle orientation in brain metastases treatment planning. Comparison of plans with optimized fixed collimator angles and optimized dynamic collimator trajectories. | Battinelli,et al., 2021 |
| The use of collimator angle optimization and jaw tracking for VMAT-based single-isocenter multiple-target stereotactic radiosurgery for up to six targets in the Varian Eclipse treatment planning system. | In this article, the authors investigated the effect on plan quality and delivery, of reducing island blocking through collimator angle optimization (CAO), and the effect of jaw tracking in this context was also investigated. | Collimator angle optimization (CAO) has limited benefit in VMAT SIMT SRS. Jaw tracking in SIMT SRS plans has minimal clinical benefits. | Collimator angle optimization (CAO) has limited benefit in VMAT SIMT SRS. Jaw tracking in SIMT SRS plans has minimal clinical benefits. | Collimator angle optimization (CAO) algorithm Jaw tracking in single-isocenter multiple-target (SIMT) stereotactic radiotherapy (SRS) plans | Investigated the effect of reducing island blocking through collimator angle optimization (CAO) Assessed the effect of jaw tracking on plan quality and delivery | Pudsey,et al., 2021 |
| Optimization of collimator angles in dual-arc volumetric modulated arc therapy planning for whole-brain radiotherapy with hippocampus and inner ear sparing. | In this article, a dual-arc volumetric modulated arc therapy (VMAT) plan for whole-brain radiotherapy with hippocampus and inner ear sparing (HIS-WBRT) was generated for 13 small-cell lung cancer patients. | The collimator angle in dual-arc VMAT planning significantly affects plan quality. Increasing the intersection angle between collimator settings improves dose distributions and reduces monitor units. | Increasing the collimator angle (Δθ) towards 90° improves plan quality. The effect of θ1/θ2 combinations on plan quality is insignificant. | Retrospective analysis of 13 small-cell lung cancer patients Generation of dual-arc VMAT plans with different collimator angles | Optimization of collimator angles in dual-arc VMAT plans for HIS-WBRT. Evaluation of plan quality and QA for different collimator settings. | Sun, et al., 2021 |
| Effect of collimator angles on the dosimetric results of volumetric modulated arc therapy planning for patients with a locally-advanced nasopharyngeal carcinoma | The effect of collimator angle on the dosimetric results of VMAT plans for patients with a locally-advanced nasopharyngeal carcinoma (LA-NPC) was evaluated and the mean doses had positive correlations and the CI had a weak positive correlation with the irradiated volume. | Increasing collimator angles in VMAT plans for LA-NPC patients increases absorbed doses to the optic apparatus. The best values for conformity index and homogeneity index were achieved at specific collimator angles. | Increasing collimator angles in VMAT plans increased absorbed doses to the optic apparatus. The best conformity index (CI) was achieved at collimator angles of 20° and 30°. | VMAT treatment planning sets were generated with different collimator angles. Dosimetric parameters such as target coverage and dose conformity were analyzed. | Evaluated the effect of collimator angle on dosimetric results of VMAT plans for LA-NPC patients Analyzed dosimetric parameters such as target coverage, OAR, and dose conformity | Kim,et al., 2017 |
| Collimator angle optimization method for volumetric-modulated arc therapy plan | In this article, a collimator angle optimization method for a volumetric-modulated arc therapy plan is proposed to dynamically optimize the angle according to the patient-specific target region information, so the manual participation degree and the degree of dependence of the plan quality on the artificial experience are reduced. | The method can dynamically optimize the collimator angle for volumetric-modulated arc therapy plans. The personalized optimization method improves plan quality and clinical efficacy. | The method can dynamically optimize the collimator angle according to the patient-specific target region information. The resulting dosimetric improvement can avoid unnecessary tumor control rate decline and normal tissue damages and improve the efficacy of clinical radiotherapy. | Three-dimensional reconstruction of target region using patient-specific information Segmented optimization of complete arc based on collimator angles and conformal indexes | The paper proposes a collimator angle optimization method for volumetric-modulated arc therapy plans. The method dynamically optimizes the collimator angle based on patient-specific target region information. | Zhang,et al., 2010 |
| Effect of the Collimator Angle on Dosimetric Verification of Volumetric Modulated Arc Therapy | In this article, the effect of the collimator angle on the results of dosimetric verification of volumetric modulated arc therapy (VMAT) plans for head and neck patients was studied. | Results of patient-specific QA for VMAT plans depend on collimator angle. Collimator angles of VMAT plans for head and neck cancer patients range between 15-25 degrees. | The collimator angle has a negative correlation with the γ-index passing rates. The accuracy of the delivered dose depends on the collimator angle. | VMAT plans with different collimator angles were generated for head and neck patients. Dosimetric verification was performed using a 2-dimensional ion chamber array. | Studied the effect of collimator angle on dosimetric verification of VMAT plans for head and neck patients. Found negative correlation between collimator angle and γ-index passing rates. | Kim et al., 2015 |
| SU‐G‐BRC‐04: Collimator Angle Optimization in Volumetric Modulated Arc Therapy | It can be concluded that collimator angles should be maintained within 15-30 deg. | Collimator angles should be maintained within 15-30 degrees. CI, HI, NTCP, and gamma passing index support this conclusion. | Collimator angles between 15-30 deg showed superior results in terms of NTCP for OAR. CI, HI, and gamma passing rates were not correlated with collimator angle. | Two sites (prostate and head and neck) were investigated. 10 plans were created with varying collimator angles from 0-90 deg. | Investigated the impact of collimator angle on plan quality and organ at risk sparing in VMAT. Concluded that collimator angles should be maintained within 15-30 degrees | Andersen et al., 2016 |
Table 4: Impact on Clinical outcomes.
Potential factors influencing the impact of collimator angle
The influence of collimator angle on radiotherapy planning is shaped by several interrelated factors, including anatomical site, treatment modality, and the range of angular rotation applied during optimization. Each of these factors plays a critical role in determining how effectively the collimator orientation contributes to improving dose conformity, sparing organs at risk, and enhancing overall treatment efficiency. Understanding these parameters is essential for ensuring that collimator adjustments are not used generically but tailored to the specific clinical scenario. This tailored approach ensures that treatment plans achieve adequate tumor coverage while minimizing unintended dose to surrounding tissues. One of the most important determinants is the treatment site, as different anatomical regions respond differently to changes in collimator orientation. Prostate cancer planning, for example, has shown limited sensitivity to collimator angle variations, with negligible differences in conformity and homogeneity across multiple angles, suggesting that the relatively simple geometry of the target reduces the influence of angular adjustments (Kim et al., 2024; Saeed et al., 2023). Conversely, brain metastases present a more complex dosimetric environment, where optimized collimator angles have been shown to significantly improve OAR sparing and inter-lesion dose separation due to the irregular and spatially separated targets involved (Shen et al., 2022). These findings emphasize that anatomical complexity and target geometry strongly dictate the potential benefits of collimator optimization. The treatment technique further modulates the importance of collimator angle selection. In conventional VMAT, specific collimator angles have been shown to enhance dose distribution by aligning more effectively with the MLC leaf motion and the geometry of the target volume. However, more advanced techniques such as hybrid VMAT (HVMAT) introduce additional flexibility that allows for a wider range of acceptable angles without significantly compromising plan quality, owing to the technique’s ability to incorporate static-field components that support dose shaping (Kim et al., 2024; Saeed et al., 2023). Additionally, the range of collimator rotation itself plays a crucial role. Research indicates that intermediate angles—typically around 20°, 30°, and 45°—produce superior dosimetric outcomes by balancing leaf travel efficiency and beam modulation, whereas very small or extreme angles can lead to suboptimal distributions, including elevated surface doses in small-target scenarios (Saeed et al., 2023; Kim et al., 2022). These combined findings show that while collimator angle adjustments hold significant potential for improving treatment efficacy, their actual impact is highly dependent on treatment site, planning technique, and selected angle range.
Implications of Collimator Angle in VMAT: Comparisons of literature findings
The collective body of evidence demonstrates that collimator angle selection in VMAT significantly influences dose distribution, although the magnitude of its impact varies by anatomical site, treatment geometry, and planning strategy. Several studies, including Yoo et al. (2014) and Jeong et al. (2014), reported that modest angles—typically around 15°—can enhance dose conformity and improve target coverage in prostate VMAT, reflected in metrics such as increased D95 and improved planning target volume (PTV) dose uniformity. For more complex scenarios, such as whole-brain radiotherapy, Niemierko et al. (2013) found that dual-arc configurations using orthogonal or near-orthogonal collimator angles (e.g., 350°/80°) produced superior dosimetric performance. These variations highlight that optimal collimator settings depend heavily on patient anatomy and the spatial characteristics of the target structures. In contrast, studies such as Xing et al. (2016) showed limited or no dosimetric improvement when adjusting collimator angles for multi-target SRS, suggesting that in highly conformal high-dose treatments, arc geometry and MLC modulation may play a more dominant role than the angle itself. The literature also reveals a critical balance between dose distribution and treatment delivery efficiency. Dynamic collimator rotation approaches (DC-VMAT) have been investigated as a means of improving efficiency by adjusting the angle throughout gantry rotation. Niemiec et al. (2016) demonstrated reductions in treatment time with DC-VMAT compared with static-angle VMAT (SC-VMAT). However, not all findings support routine adoption of dynamic approaches. Zhang et al. (2023) reported that in single-isocenter multitarget SRS, DC-VMAT provided limited clinical benefit and introduced additional mechanical complexity that could outweigh its efficiency advantages. Similarly, algorithm-based collimator angle optimization (CAO), explored by Wang et al. (2020), shows potential for automating angle selection and improving plan quality, but its effectiveness is highly dependent on case complexity and the relative weighting of planning objectives. Together, these findings indicate that while angle optimization and dynamic strategies can improve workflow and potentially enhance precision, they must be applied judiciously and tailored to the clinical scenario. Another recurring theme in the literature is the impact of collimator angle on sparing organs at risk. Yoo et al. (2014) observed that certain angle combinations in double-arc VMAT led to reduced rectal doses in prostate cancer treatments, illustrating how beam orientation influences the interplay between MLC projection and organ geometry. Thomas et al. (2023) further supported the trend that angles between 15° and 30° often strike an effective balance between target coverage and OAR protection across several anatomical sites. However, some investigations—such as Xing et al. (2016) in multitarget SRS—found negligible differences in OAR dose with varying angles, reinforcing that the benefits of angle selection are not universal and depend strongly on spatial complexity. Advancements such as dynamic collimator adjustment, as explored by Zhang et al. (2016) and supported by work from Sun et al. (2021), suggest that real-time modulation of angle could further optimize both OAR sparing and delivery efficiency. Nonetheless, widespread clinical integration requires additional validation due to challenges related to treatment verification, mechanical reliability, and integration into existing planning workflows. Overall, current evidence supports collimator angle optimization as an important but context-dependent component of VMAT planning that warrants continued investigation.
Meta-analysis of the Impact of Collimator Angle on Target Coverage
The synthesis of studies in Table 5 indicates that collimator angle has a limited direct influence on baseline target coverage in volumetric modulated arc therapy (VMAT), but plays a significant role in optimizing plan quality, efficiency, and robustness. Across prostate cancer studies, target coverage remained largely unchanged over a wide range of collimator angles (0°–90°), demonstrating the robustness of modern VMAT optimization algorithms (Isa et al., 2014; Saeed et al., 2023). Despite this stability, important differences were observed in plan quality metrics such as conformity index (CI), homogeneity index (HI), and monitor units (MUs), suggesting that collimator angle primarily functions as an optimization parameter rather than a determinant of target dose adequacy. This distinction is clinically relevant, as improved conformity and homogeneity contribute to better dose shaping and reduced irradiation of surrounding normal tissues. A consistent and well-supported finding across the included studies is the superiority of moderate non-zero collimator angles, typically within the range of 15°–45°. Multiple investigations demonstrated that this range yields improved conformity, homogeneity, and treatment efficiency. For instance, optimal plan performance was reported at 20°–45° in prostate VMAT (Saeed et al., 2023), while 45° produced the best conformity and homogeneity indices in phantom-based analyses (Isa et al., 2014). Similarly, in nasopharyngeal carcinoma, angles between 15° and 30° achieved superior target coverage and reduced monitor units, whereas very low angles (5°–10°) resulted in suboptimal coverage (Thomas et al., 2023). These findings suggest that moderate collimator rotation enhances multileaf collimator (MLC) modulation and reduces geometric inefficiencies, such as tongue-and-groove effects, thereby improving dose distribution without compromising coverage. The impact of collimator angle is further influenced by anatomical complexity and treatment technique. In relatively simple geometries, such as prostate VMAT, angle selection primarily refines plan quality. However, in more complex scenarios, including craniospinal irradiation and stereotactic radiosurgery (SRS) for multiple brain metastases, collimator angle becomes a more critical planning variable. For example, non-zero collimator angles eliminated dose gaps at field junctions in craniospinal irradiation, thereby improving treatment robustness (Li et al., 2015). In addition, sub-arc collimator angle optimization (SACAO) significantly enhanced conformity, homogeneity, gradient index, and normal tissue sparing, while reducing monitor units and field size in multi-target SRS (Battinelli et al., 2021). These findings indicate that the clinical importance of collimator angle increases with treatment complexity and modulation demands. Another important dimension highlighted by the meta-analysis is the influence of collimator angle on treatment deliverability and mechanical accuracy. Higher collimator angles have been associated with reduced gamma index passing rates, indicating potential discrepancies between planned and delivered dose distributions (Kim et al., 2015). More critically, collimator angle misalignment exceeding ±1° has been shown to significantly degrade target coverage and homogeneity, particularly for large planning target volumes, with substantial variations in dosimetric indices (Puchades-Puchades et al., 2015). These findings emphasize that the benefits of optimal angle selection are contingent upon precise mechanical calibration and rigorous quality assurance, as inaccuracies in collimator positioning can negate dosimetric advantages. Overall, the evidence supports a hierarchical interpretation in which collimator angle has a modest direct effect on target coverage but a substantial indirect effect on plan quality, robustness, and clinical reliability. Moderate angles (15°–45°) consistently provide the best balance between dosimetric performance and efficiency, while advanced or automated optimization strategies are particularly beneficial in complex cases. Importantly, the clinical gains associated with collimator angle optimization depend on accurate delivery and quality assurance. Therefore, collimator angle should be considered as part of an integrated treatment planning strategy rather than an isolated parameter, with selection tailored to anatomical complexity, treatment technique, and machine performance.
| Theme | Key Findings | Consensus Level | Evidence Strength | Supporting Studies |
| Target Coverage Stability | Minimal variation in PTV coverage across most angles in standard VMAT | High | Moderate–Strong | Saeed et al. (2023), Isa et al. (2014), Li et al. (2015) |
| Optimal Angle Range (15°–45°) | Moderate angles improve conformity, homogeneity, and efficiency | High | Strong | Saeed et al. (2023), Isa et al. (2014), Thomas et al. (2023) |
| Low Angles (≈0°–10°) | May reduce coverage and plan quality in some sites | Moderate | Moderate | Thomas et al. (2023) |
| High Angles (>45°–90°) | Mixed effects: possible OAR sparing but reduced QA performance | Moderate | Moderate | Isa et al. (2014), Kim et al. (2015) |
| Monitor Units & Efficiency | Moderate angles reduce MUs; some high angles increase complexity | Moderate | Moderate | Thomas et al. (2023), Battinelli et al. (2021), Li et al. (2015) |
| OAR Sparing | No consistent universal trend; depends on geometry | Low–Moderate | Limited–Moderate | Isa et al. (2014), Battinelli et al. (2021) |
| Deliverability / QA | Higher angles may reduce gamma passing rates | Moderate | Moderate | Kim et al. (2015) |
| Collimator Angle Error | Misalignment >±1° significantly degrades coverage and HI | High | Strong | Puchades-Puchades et al. (2015) |
| Complex Cases (SRS, CSI) | Angle optimization significantly improves plan quality and robustness | High | Strong | Battinelli et al. (2021), Li et al. (2015) |
Table 5: Meta-analysis of the Impact of Collimator Angle on Target Coverage.
Meta-Analysis results Summary for Organ-at-Risk (OAR) Sparing
The meta-analysis presented in Table 6 demonstrates that organ-at-risk (OAR) sparing in modern radiotherapy is predominantly influenced by multileaf collimator (MLC) utilization and advanced treatment delivery techniques, with additional contributions from geometric and planning optimizations. Across multiple studies, MLC-based approaches consistently achieved significant reductions in dose to critical structures such as the heart, lungs, and left anterior descending artery compared to conventional shielding methods (Mahani et al., 2023; Momeni, 2023). Furthermore, improvements in hardware design, particularly the use of narrower MLC leaf widths, were associated with enhanced dose conformity, steeper gradients, and superior normal tissue sparing (Ohira et al., 2021). Advanced delivery techniques, including volumetric modulated arc therapy (VMAT) and dynamic trajectory radiotherapy (DTRT), further strengthened OAR protection, with DTRT showing notable improvements over VMAT in complex head and neck cases (Bertholet et al., 2022; Serarslan et al., 2023). While collimator angle variation alone appears to have a limited and context-dependent impact on OAR dose (Saeed et al., 2023), more sophisticated planning strategies such as split X-jaw techniques and dynamic beam modulation provide meaningful enhancements in both OAR sparing and target coverage (Sarma et al., 2023). Overall, the evidence supports a multifactorial approach in which optimal OAR protection is achieved through the combined use of advanced MLC design, innovative delivery techniques, and individualized treatment planning strategies.
| Theme | Pooled Findings | Consistency of Evidence | Strength of Evidence | Key Supporting Studies | Clinical Interpretation |
| MLC-based OAR Dose Reduction | MLC significantly reduces dose to critical organs (heart, LAD, lungs, out-of-field tissues) compared to conventional shielding | High | Strong | Mahani et al. (2023); Momeni (2023) | MLC should be standard for OAR protection in modern radiotherapy |
| Effect of MLC Leaf Width | Narrower MLC (e.g., 2.5 mm) improves conformity, dose gradient, and normal tissue sparing | High | Strong | Ohira et al. (2021) | Use high-definition MLC where available for better sparing, especially in SRS |
| Advanced Techniques (VMAT, DTRT, A-IMRT) | Advanced delivery techniques improve OAR sparing compared to conventional IMRT; VMAT and DTRT show superior performance | High | Strong | Serarslan et al. (2023); Bertholet et al. (2022) | Prefer VMAT/DTRT for complex cases requiring enhanced sparing |
| Collimator Geometry Optimization | Collimator angle and beam geometry have modest but context-dependent effects on OAR dose | Moderate | Moderate | Saeed et al. (2023); Serarslan et al. (2023) | Angle optimization should be used as a refinement, not primary strategy |
| Technique-based Optimization (Split X-jaw, Dynamic Motion) | Advanced planning techniques improve both OAR sparing and target coverage | Moderate–High | Moderate–Strong | Sarma et al. (2023); Bertholet et al. (2022) | Incorporate geometric/trajectory-based optimization in large or complex targets |
| Comparison with Conventional Shielding | MLC shielding is superior to traditional blocks in reducing unintended dose | High | Strong | Momeni (2023) | Replace block shielding with MLC-based approaches in clinical practice |
| Overall Determinant of OAR Sparing | OAR sparing is multifactorial: depends on MLC design, technique, and planning strategy | High | Strong | All studies | Combine hardware + technique optimization for best outcomes |
Table 6: Meta-Analysis results Summary for Organ-at-Risk (OAR) Sparing.
Meta-Analysis Summary Results for the Impact of Collimator Angle on Clinical Outcomes
The meta-analysis summarized in Table 7 demonstrates that collimator angle optimization influences clinical outcomes primarily through improvements in plan quality, treatment efficiency, and normal tissue protection rather than direct enhancement of target coverage. A consistent finding across multiple studies is that moderate collimator angles, typically within the range of 15°–45°, provide optimal dosimetric performance, resulting in improved conformity index (CI), homogeneity index (HI), and, in some cases, reduced normal tissue complication probability (NTCP) (Andersen et al., 2016; Kim et al., 2017; Saeed et al., 2023). Importantly, target coverage remains largely unchanged across varying collimator angles, indicating that collimator angle serves as a refinement parameter rather than a primary determinant of dose delivery. These improvements in dosimetric quality are clinically relevant, as enhanced conformity and homogeneity are associated with better tumor control and reduced radiation-induced toxicity, thereby improving the overall therapeutic ratio. Furthermore, the analysis highlights the growing importance of advanced and automated collimator angle optimization strategies, particularly in complex treatment scenarios such as multiple brain metastases and whole-brain radiotherapy. Techniques such as sub-arc collimator angle optimization (SACAO) and dynamic trajectory optimization have demonstrated substantial improvements in plan quality, including reductions in monitor units and unnecessary irradiation of normal tissue (Battinelli et al., 2021; Shen et al., 2022). However, the benefits of collimator angle optimization are not universal, as some studies report limited impact in specific treatment configurations, such as single-isocenter multiple-target stereotactic radiosurgery (Pudsey et al., 2021). Additionally, higher collimator angles may introduce trade-offs, including increased dose to sensitive structures and reduced delivery accuracy, as reflected by lower gamma index passing rates (Kim et al., 2015; Kim et al., 2017). Overall, these findings suggest that while collimator angle optimization can enhance clinical outcomes, its effectiveness is context-dependent and should be integrated with other planning strategies to achieve optimal and clinically reliable results.
| Domain | Pooled Findings | Consistency | Strength of Evidence | Key Studies | Clinical Impact |
| Optimal Angle Range | Angles between 15°–45° consistently improve CI, HI, and overall plan quality | High | Strong | Saeed et al. (2023); Andersen et al. (2016); Kim et al. (2017) | Recommended default range for improved dosimetric outcomes |
| Target Coverage | Minimal or no significant change in target coverage across angles | High | Strong | Saeed et al. (2023); Kim et al. (2017) | Angle mainly refines plan quality rather than coverage |
| Plan Quality (CI, HI, GI) | Moderate angles and optimization techniques improve conformity, homogeneity, and gradient index | High | Strong | Shen et al. (2022); Battinelli et al. (2021); Sun et al. (2021) | Enhances dose shaping and treatment precision |
| Treatment Efficiency | Significant reductions in monitor units (up to ~41%) and field size with optimized angles | Moderate–High | Strong | Shen et al. (2022); Sun et al. (2021) | Improves delivery time and machine efficiency |
| Advanced Optimization Techniques | Dynamic and algorithm-based optimization (SACAO, CAO) outperform fixed-angle approaches | High | Strong | Zhang et al. (2010); Battinelli et al. (2021); Shen et al. (2022) | Supports automation and patient-specific planning |
| OAR Dose / NTCP | Moderate angles reduce NTCP; higher angles may increase dose to sensitive structures | Moderate | Moderate–Strong | Andersen et al. (2016); Kim et al. (2017) | Requires balance between tumor control and toxicity |
| Deliverability / QA | Higher angles may reduce gamma passing rates and delivery accuracy | Moderate | Moderate | Kim et al. (2015) | QA verification critical at higher angles |
| Technique Dependency | Some techniques (e.g., SIMT SRS) show limited benefit from angle optimization | Moderate | Moderate | Pudsey et al. (2021) | Angle optimization not universally beneficial |
| Complex Case Sensitivity | Greater benefit in multi-target SRS and whole-brain radiotherapy cases | High | Strong | Battinelli et al. (2021); Sun et al. (2021) | Critical in complex geometries |
Table 7: Meta-Analysis Summary Table: Impact of Collimator Angle on Clinical Outcomes.
This systematic review and meta-analysis provide strong evidence that collimator angle plays a secondary yet clinically significant role in VMAT planning, primarily influencing plan quality, efficiency, and treatment robustness rather than directly affecting baseline target coverage. Across multiple studies, target coverage remained consistently stable over a wide angular range (0°–90°), highlighting the robustness of modern inverse planning algorithms. However, optimal dosimetric performance was consistently achieved within moderate collimator angles of 15°–45°, with specific optimal values of 20°, 30°, and 45° identified in prostate cancer planning, and 15°–30° in nasopharyngeal carcinoma, achieving PTV coverage levels of approximately 92–94%. The analysis demonstrates that collimator angle optimization significantly enhances key plan quality metrics, including conformity index (CI), homogeneity index (HI), and monitor unit (MU) efficiency. Advanced optimization strategies, such as Sub-Arc Collimator Angle Optimization (SACAO), further improved treatment quality by reducing monitor units by approximately 15.7% and field size by 41.1%, while enhancing dose conformity and normal tissue sparing. These improvements are particularly pronounced in complex treatment scenarios, such as stereotactic radiosurgery (SRS) for multiple brain metastases and craniospinal irradiation, where optimized collimator angles eliminate dose gaps and improve treatment robustness. Despite these benefits, the findings highlight important trade-offs related to treatment deliverability and mechanical accuracy. Higher collimator angles (>45°) were associated with decreased γ-index passing rates, with reductions of up to 5.6%, indicating potential discrepancies between planned and delivered dose distributions. More critically, collimator misalignment exceeding ±1° was shown to significantly degrade target coverage and homogeneity, with variations in HI reaching up to 75%, particularly for large planning target volumes. These results underscore the necessity of rigorous quality assurance protocols and precise mechanical calibration to ensure safe and effective treatment delivery. In terms of organ-at-risk (OAR) sparing, the analysis confirms that collimator angle alone is not the primary determinant. Instead, OAR dose reduction is predominantly influenced by multileaf collimator (MLC) design, leaf width, and advanced delivery techniques. MLC-based approaches achieved dose reductions of up to 20% in critical structures such as the heart and lungs, while narrower MLC leaf widths (e.g., 2.5 mm) provided superior dose gradients and normal tissue sparing compared to wider leaves (5 mm). Additionally, advanced techniques such as VMAT, dynamic trajectory radiotherapy (DTRT), and split X-jaw planning further enhanced OAR protection and treatment efficiency. Overall, this study establishes that collimator angle should be considered as part of a multifactorial, patient-specific optimization strategy in VMAT planning. Moderate angles (15°–45°) are recommended as a practical default for most clinical scenarios, while advanced and automated optimization techniques should be employed for complex cases. Future research should focus on large-scale clinical trials and the development of standardized, automated collimator angle optimization protocols to further improve treatment precision, efficiency, and long-term clinical outcomes.
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I Appreciate the Opportunity to Share my Experience with the Journal of Clinical Research and Reports. The peer review process was timely and constructive, and the feedback provided helped improve the quality of our manuscript. The editorial office was professional, responsive, and supportive throughout the process, ensuring smooth communication and efficient handling of the submission. Overall, it was a positive experience collaborating with your team.
Dear Mercy Grace, Editorial Coordinator of Obstetrics Gynecology and Reproductive Sciences, We would like to express our gratitude for your help at all stages of publishing and editing the article. The editors of the magazine answer all the necessary questions and help at every stage. We will definitely continue to cooperate and publish other works in the Obstetrics Gynecology and Reproductive Sciences! Best wishes from, Alla Konstantinovna Politova,
Dear Maria Emerson, Editorial Coordinator of International Journal of Clinical Case Reports and Reviews, What distinguishes International Journal of Clinical Case Report and Review is not only the scientific rigor of its publications, but the intellectual climate in which research is evaluated. The submission process is refreshingly free of unnecessary formal barriers and bureaucratic rituals that often complicate academic publishing without adding real value. The peer-review system is demanding yet constructive, guided by genuine scientific dialogue rather than hierarchical or authoritarian attitudes. Reviewers act as collaborators in improving the manuscript, not as gatekeepers imposing arbitrary standards. This journal offers a rare balance: high methodological standards combined with a respectful, transparent, and supportive editorial approach. In an era where publishing can feel more burdensome than research itself, this platform restores the original purpose of peer review — to refine ideas, not to obstruct them Prof. Perlat Kapisyzi, FCCP PULMONOLOGIST AND THORACIC IMAGING.
Dear Reader: We have published several articles in the Auctores Publishing, LLC, journal, Clinical Medical Reviews and Reports in recent years (CMRR). This is an ‘open access’ journal and the following are our observations. From the initial invitation to submit an article, to the final edits of galley proofs, we have found CMRR personnel to be professional, responsive, rapid and thorough. This entire process begins with Catherine Mitchell, Editorial Coordinator. She is simply outstanding, and, I believe, unparalleled in her capacity. I cannot imagine a more responsive and dedicated Editorial Coordinator. As I read the dates and timing of her correspondence with us, it seems that she never sleeps. I hope Auctores Publishing, LLC, appreciates her efforts as much as these authors do. Thank you to Auctores Publishing, LLC, to the Editorial Staff/Board, and to Catherine Mitchell from a grateful author(s).
Dear Maria Emerson, Editorial Coordinator of - Journal of Clinical Research and Reports. ''I am pleased to provide this testimonial following the publication of our recent case report in this journal. The peer review process was rigorous, constructive, thorough, and conducted in a timely manner. The reviewers’ comments were thoughtful, detailed, and highly constructive, contributing substantially to the refinement, clarity, and scientific robustness of our manuscript. The process was conducted with professionalism and academic integrity throughout. The support provided by the editorial office was exemplary. Communication was consistently prompt, clear, and courteous at all stages of the submission and publication process. The editorial team demonstrated a high level of organization and responsiveness, ensuring that all queries were addressed efficiently and that the process remained transparent and well-coordinated. The overall quality of the journal is reflected in its strong editorial standards, commitment to scientific excellence, and dedication to publishing clinically meaningful research. It has been a privilege to publish our work in this journal, and we would welcome the opportunity to contribute further in the future.'' Best wishes from, Dr. Efstratios Trogkanis, Cardiologist.
Dear Grace Pierce, Editorial Coordinator of the journal IJCCR, I had a very positive experience with Auctores - Journal throughout the publication process. The Editorial Team was highly responsive, professional, and supportive at every stage. I would like to extend my sincere thanks to the Editor: Grace Pierce, for her guidance and assistance. The peer-review process was smooth and constructive, helping improve the quality of my work. I would gladly recommend Auctores Journal to fellow researchers and authors. Dr. SABITA SINHA, Medical Oncologist, MD (Electro Homeopathy).
Dear Mayra Duenas, Editorial Coordinator of the journal IJCCR, I write here a little on my experience as an author submitting to the International Journal of Clinical Case Reports and Reviews (IJCCR). This was my first submission to IJCCR and my manuscript was inherently an outsider’s effort. It attempted to broadly identify and then make some sense of life’s under-appreciated mysteries. I initially had responded to a request for possible submissions. I then contacted IJCCR with a tentative topic for a manuscript. They quickly got back with an approval for the submission, but with a particular requirement that it be medically relevant. I then put together a manuscript and submitted it. After the usual back-and-forth over forms and formality, the manuscript was sent off for reviews. Within 2 weeks I got back 4 reviews which were both helpful and also surprising. Surprising in that the topic was somewhat foreign to medical literature. My subsequent updates in response to the reviewer comments went smoothly and in short order I had a series of proofs to evaluate. All in all, the whole publication process seemed outstanding. It was both helpful in terms of the paper’s content and also in terms of its efficient and friendly communications. Thank you all very much. Sincerely, Ted Christopher, Rochester, NY.
International Journal of Clinical Case Reports and Reviews is a high quality journal that has a clear and concise submission process. The peer review process was comprehensive and constructive. Support from the editorial office was excellent, since the administrative staff were responsive. The journal provides a fast and timely publication timeline.
Dear Cecilia Lilly, Editorial Coordinator, Endocrinology and Disorders, Thank you so much for your quick response regarding reviewing and all process till publishing our manuscript entitled: Prevalence of Pre-Diabetes and its Associated Risk Factors Among Nile College Students, Sudan. Best regards, Dr Mamoun Magzoub.
Dear Editorial Team, Clinical Cardiology and Cardiovascular Interventions. I am really grateful for the peers review; their feedback gave me the opportunity to reflect on the message and impact of my work and to ameliorate the article. The editors did a great job in addition by encouraging me to continue with the process of publishing.
Dear Mayra Duenas, Editorial Coordinator of ‘International Journal of Clinical Case Reports and Reviews Herewith I confirm an optimal peer review process and a great support of the editorial office of the present journal
Dear Maria Emerson, Editorial Coordinator of ‘International Journal of Clinical Case Reports and Reviews’, I appreciate the opportunity to publish my article with your journal. The editorial office provided clear communication during the submission and review process, and I found the overall experience professional and constructive. Best regards, Elena Salvatore.
Dear Editorial Team, Journal-Clinical Cardiology and Cardiovascular Interventions, “Publishing my article with Clinical Cardiology and Cardiovascular Interventions has been a highly positive experience. The peer-review process was rigorous yet supportive, offering valuable feedback that strengthened my work. The editorial team demonstrated exceptional professionalism, prompt communication, and a genuine commitment to maintaining the highest scientific standards. I am very pleased with the publication quality and proud to be associated with such a reputable journal.” Warm regards, Dr. Mahmoud Kamal Moustafa Ahmed
Dear Editorial Team, Clinical Cardiology and Cardiovascular Interventions. It was truly a rewarding experience to work with the journal “Clinical Cardiology and Cardiovascular Interventions”. The peer review process was insightful and encouraging, helping us refine our work to a higher standard. The editorial office offered exceptional support with prompt and thoughtful communication. I highly value the journal’s role in promoting scientific advancement and am honored to be part of it. Best regards, Meng-Jou Lee, MD, Department of Anesthesiology, National Taiwan University Hospital.
Dear Maria Emerson, Editorial Coordinator, Journal of Clinical Research and Reports. Thank you for publishing our case report: "Clinical Case of Effective Fetal Stem Cells Treatment in a Patient with Autism Spectrum Disorder" within the "Journal of Clinical Research and Reports" being submitted by the team of EmCell doctors from Kyiv, Ukraine. We much appreciate a professional and transparent peer-review process from Auctores. All research Doctors are so grateful to your Editorial Office and Auctores Publishing support! I amiably wish our article publication maintained a top quality of your International Scientific Journal. My best wishes for a prosperity of the Journal of Clinical Research and Reports. Hope our scientific relationship and cooperation will remain long lasting. Thank you very much indeed. Kind regards, Dr. Andriy Sinelnyk Cell Therapy Center EmCell
I recommend without hesitation submitting relevant papers on medical decision making to the International Journal of Clinical Case Reports and Reviews. I am very grateful to the editorial staff. Maria Emerson was a pleasure to communicate with. The time from submission to publication was an extremely short 3 weeks. The editorial staff submitted the paper to three reviewers. Two of the reviewers commented positively on the value of publishing the paper. The editorial staff quickly recognized the third reviewer’s comments as an unjust attempt to reject the paper. I revised the paper as recommended by the first two reviewers.
Dear Chrystine Mejia, Editorial Coordinator, Journal of Neurodegeneration and Neurorehabilitation. “The peer review process was efficient and constructive, and the editorial office provided excellent communication and support throughout. The journal ensures scientific rigor and high editorial standards, while also offering a smooth and timely publication process. We sincerely appreciate the work of the editorial team in facilitating the dissemination of innovative approaches such as the Bonori Method.” Best regards, Dr. Matteo Bonori.
Dear Maria Emerson, Editorial Coordinator, we have deeply appreciated the professionalism demonstrated by the International Journal of Clinical Case Reports and Reviews. The reviewers have extensive knowledge of our field and have been very efficient and fast in supporting the process. I am really looking forward to further collaboration. Thanks. Best regards, Dr. Claudio Ligresti
Dear Ms. Mayra Duenas, Editorial Coordinator, International Journal of Clinical Case Reports and Reviews. “The International Journal of Clinical Case Reports and Reviews represented the “ideal house” to share with the research community a first experience with the use of the Simeox device for speech rehabilitation. High scientific reputation and attractive website communication were first determinants for the selection of this Journal, and the following submission process exceeded expectations: fast but highly professional peer review, great support by the editorial office, elegant graphic layout. Exactly what a dynamic research team - also composed by allied professionals - needs!" From, Chiara Beccaluva, PT - Italy.
Dear Clarissa Eric, Editorial Coordinator, Journal of Clinical Case Reports and Studies, Auctores Publishing LLC, USA Office: +1-(302)-520-2644. I would like to express my sincere appreciation for the efficient and professional handling of my case report by the ‘Journal of Clinical Case Reports and Studies’. The peer review process was not only fast but also highly constructive—the reviewers’ comments were clear, relevant, and greatly helped me improve the quality and clarity of my manuscript. I also received excellent support from the editorial office throughout the process. Communication was smooth and timely, and I felt well guided at every stage, from submission to publication. The overall quality and rigor of the journal are truly commendable. I am pleased to have published my work with Journal of Clinical Case Reports and Studies, and I look forward to future opportunities for collaboration. Sincerely, Aline Tollet, UCLouvain.
Dear Chrystine Mejia, Editorial Coordinator, Journal of Neurodegeneration and Neurorehabilitation, Auctores Publishing LLC, We would like to thank the editorial team for the smooth and high-quality communication leading up to the publication of our article in the Journal of Neurodegeneration and Neurorehabilitation. The reviewers have extensive knowledge in the field, and their relevant questions helped to add value to our publication. Kind regards, Dr. Ravi Shrivastava.
Dear Clarissa Eric, Editorial Coordinator, Journal of Clinical Case Reports and Studies, I would like to express my deep admiration for the exceptional professionalism demonstrated by your journal. I am thoroughly impressed by the speed of the editorial process, the substantive and insightful reviews, and the meticulous preparation of the manuscript for publication. Additionally, I greatly appreciate the courteous and immediate responses from your editorial office to all my inquiries. Best Regards, Dariusz Ziora
Dear Ashley Rosa, Editorial Coordinator, International Journal of Clinical Case Reports and Reviews, Auctores Publishing LLC. Thank you for publishing our article, Exploring Clozapine's Efficacy in Managing Aggression: A Multiple Single-Case Study in Forensic Psychiatry in the international journal of clinical case reports and reviews. We found the peer review process very professional and efficient. The comments were constructive, and the whole process was efficient. On behalf of the co-authors, I would like to thank you for publishing this article. With regards, Dr. Jelle R. Lettinga.
Dear Jessica Magne, Editorial Coordinator, Clinical Cardiology and Cardiovascular Interventions, Auctores Publishing LLC. The peer review process of the journal of Clinical Cardiology and Cardiovascular Interventions was excellent and fast, as was the support of the editorial office and the quality of the journal. Kind regards Walter F. Riesen Prof. Dr. Dr. h.c. Walter F. Riesen.
Dear Erin Aust, Editorial Coordinator, Journal of General Medicine and Clinical Practice. We are pleased to share our experience with the “Journal of General Medicine and Clinical Practice”, following the successful publication of our article. The peer review process was thorough and constructive, helping to improve the clarity and quality of the manuscript. We are especially thankful to Ms. Erin Aust, the Editorial Coordinator, for her prompt communication and continuous support throughout the process. Her professionalism ensured a smooth and efficient publication experience. The journal upholds high editorial standards, and we highly recommend it to fellow researchers seeking a credible platform for their work. Best wishes By, Dr. Rakhi Mishra.
Dr Hala Al Shaikh This is to acknowledge that the peer review process for the article ’ A Novel Gnrh1 Gene Mutation in Four Omani Male Siblings, Presentation and Management ’ sent to the International Journal of Clinical Case Reports and Reviews was quick and smooth. The editorial office was prompt with easy communication.
Dear Agrippa Hilda, Editorial Coordinator, Journal of Neuroscience and Neurological Surgery. The entire process including article submission, review, revision, and publication was extremely easy. The journal editor was prompt and helpful, and the reviewers contributed to the quality of the paper. Thank you so much! Eric Nussbaum, MD
Dear Ashley Rosa, Editorial Coordinator, International Journal of Clinical Case Reports and Reviews. Many thanks for publishing this manuscript after I lost confidence the editors were most helpful, more than other journals Best wishes from, Susan Anne Smith, PhD. Australian Breastfeeding Association.
Dear Maria Emerson, Editorial Coordinator, International Journal of Clinical Case Reports and Reviews, Auctores Publishing LLC. I am delighted to have published our manuscript, "Acute Colonic Pseudo-Obstruction (ACPO): A rare but serious complication following caesarean section." I want to thank the editorial team, especially Maria Emerson, for their prompt review of the manuscript, quick responses to queries, and overall support. Yours sincerely Dr. Victor Olagundoye.
Dear Jessica Magne, Editorial Coordinator, Clinical Cardiology and Cardiovascular Interventions, Auctores Publishing LLC. I appreciate the journal (JCCI) editorial office support, the entire team leads were always ready to help, not only on technical front but also on thorough process. Also, I should thank dear reviewers’ attention to detail and creative approach to teach me and bring new insights by their comments. Surely, more discussions and introduction of other hemodynamic devices would provide better prevention and management of shock states. Your efforts and dedication in presenting educational materials in this journal are commendable. Best wishes from, Farahnaz Fallahian.
Dear Ashley Rosa, Editorial Coordinator of the journal - Psychology and Mental Health Care. " The process of obtaining publication of my article in the Psychology and Mental Health Journal was positive in all areas. The peer review process resulted in a number of valuable comments, the editorial process was collaborative and timely, and the quality of this journal has been quickly noticed, resulting in alternative journals contacting me to publish with them." Warm regards, Susan Anne Smith, PhD. Australian Breastfeeding Association.
Dear Jessica, and the super professional team of the ‘Clinical Cardiology and Cardiovascular Interventions’ I am sincerely grateful to the coordinated work of the journal team for the no problem with the submission of my manuscript: “Cardiometabolic Disorders in A Pregnant Woman with Severe Preeclampsia on the Background of Morbid Obesity (Case Report).” The review process by 5 experts was fast, and the comments were professional, which made it more specific and academic, and the process of publication and presentation of the article was excellent. I recommend that my colleagues publish articles in this journal, and I am interested in further scientific cooperation. Sincerely and best wishes, Dr. Oleg Golyanovskiy.
To Dear Erin Aust – Editorial Coordinator of Journal of General Medicine and Clinical Practice! I declare that I am absolutely satisfied with your work carried out with great competence in following the manuscript during the various stages from its receipt, during the revision process to the final acceptance for publication. Thank Prof. Elvira Farina
My article, titled 'No Way Out of the Smartphone Epidemic Without Considering the Insights of Brain Research,' has been republished in the International Journal of Clinical Case Reports and Reviews. The review process was seamless and professional, with the editors being both friendly and supportive. I am deeply grateful for their efforts.
We found the peer review process quick and positive in its input. The support from the editorial officer has been very agile, always with the intention of improving the article and taking into account our subsequent corrections.
Dear Jessica Magne, with gratitude for the joint work. Fast process of receiving and processing the submitted scientific materials in “Clinical Cardiology and Cardiovascular Interventions”. High level of competence of the editors with clear and correct recommendations and ideas for enriching the article.
I thank the ‘Journal of Clinical Research and Reports’ for accepting this article for publication. This is a rigorously peer reviewed journal which is on all major global scientific data bases. I note the review process was prompt, thorough and professionally critical. It gave us an insight into a number of important scientific/statistical issues. The review prompted us to review the relevant literature again and look at the limitations of the study. The peer reviewers were open, clear in the instructions and the editorial team was very prompt in their communication. This journal certainly publishes quality research articles. I would recommend the journal for any future publications.
"I am grateful for the opportunity of contributing to [International Journal of Clinical Case Reports and Reviews] and for the rigorous review process that enhances the quality of research published in your esteemed journal. I sincerely appreciate the time and effort of your team who have dedicatedly helped me in improvising changes and modifying my manuscript. The insightful comments and constructive feedback provided have been invaluable in refining and strengthening my work".
To Dear Erin Aust, I would like to express my heartfelt appreciation for the opportunity to have my work published in this esteemed journal. The entire publication process was smooth and well-organized, and I am extremely satisfied with the final result. The Editorial Team demonstrated the utmost professionalism, providing prompt and insightful feedback throughout the review process. Their clear communication and constructive suggestions were invaluable in enhancing my manuscript, and their meticulous attention to detail and dedication to quality are truly commendable. Additionally, the support from the Editorial Office was exceptional. From the initial submission to the final publication, I was guided through every step of the process with great care and professionalism. The team's responsiveness and assistance made the entire experience both easy and stress-free. I am also deeply impressed by the quality and reputation of the journal. It is an honor to have my research featured in such a respected publication, and I am confident that it will make a meaningful contribution to the field.
I would like to express my sincere gratitude for the support and efficiency provided by the editorial office throughout the publication process of my article, “Delayed Vulvar Metastases from Rectal Carcinoma: A Case Report.” I greatly appreciate the assistance and guidance I received from your team, which made the entire process smooth and efficient. The peer review process was thorough and constructive, contributing to the overall quality of the final article. I am very grateful for the high level of professionalism and commitment shown by the editorial staff, and I look forward to maintaining a long-term collaboration with the International Journal of Clinical Case Reports and Reviews.
Dear Agrippa Hilda- Editorial Coordinator of Journal of Neuroscience and Neurological Surgery, "The peer review process was very quick and of high quality, which can also be seen in the articles in the journal. The collaboration with the editorial office was very good."
I would like to offer my testimony in the support. I have received through the peer review process and support the editorial office where they are to support young authors like me, encourage them to publish their work in your esteemed journals, and globalize and share knowledge globally. I really appreciate your journal, peer review, and editorial office.
My experience publishing in International Journal of Clinical Case Reports and Reviews was exceptional. I Come forth to Provide a Testimonial Covering the Peer Review Process and the editorial office for the Professional and Impartial Evaluation of the Manuscript.
My experience publishing in Psychology and Mental Health Care was exceptional. The peer review process was rigorous and constructive, with reviewers providing valuable insights that helped enhance the quality of our work. The editorial team was highly supportive and responsive, making the submission process smooth and efficient. The journal's commitment to high standards and academic rigor makes it a respected platform for quality research. I am grateful for the opportunity to publish in such a reputable journal.
My Testimonial Covering as fellowing: Lin-Show Chin. The peer reviewers process is quick and effective, the supports from editorial office is excellent, the quality of journal is high. I would like to collabroate with Internatioanl journal of Clinical Case Reports and Reviews.
Dealing with The Journal of Neurology and Neurological Surgery was very smooth and comprehensive. The office staff took time to address my needs and the response from editors and the office was prompt and fair. I certainly hope to publish with this journal again.Their professionalism is apparent and more than satisfactory. Susan Weiner
Dear Editorial Coordinator of the Journal of Nutrition and Food Processing! "I would like to thank the Journal of Nutrition and Food Processing for including and publishing my article. The peer review process was very quick, movement and precise. The Editorial Board has done an extremely conscientious job with much help, valuable comments and advices. I find the journal very valuable from a professional point of view, thank you very much for allowing me to be part of it and I would like to participate in the future!”
Dear Monica Gissare, - Editorial Coordinator of Nutrition and Food Processing. ¨My testimony with you is truly professional, with a positive response regarding the follow-up of the article and its review, you took into account my qualities and the importance of the topic¨.
Dear Dr. Jessica Magne, Editorial Coordinator 0f Clinical Cardiology and Cardiovascular Interventions, I hope this message finds you well. I want to express my utmost gratitude for your excellent work and for the dedication and speed in the publication process of my article titled "Navigating Innovation: Qualitative Insights on Using Technology for Health Education in Acute Coronary Syndrome Patients." I am very satisfied with the peer review process, the support from the editorial office, and the quality of the journal. I hope we can maintain our scientific relationship in the long term.
Clinical Cardiology and Cardiovascular Interventions, I would like to express my sincerest gratitude for the trust placed in our team for the publication in your journal. It has been a true pleasure to collaborate with you on this project. I am pleased to inform you that both the peer review process and the attention from the editorial coordination have been excellent. Your team has worked with dedication and professionalism to ensure that your publication meets the highest standards of quality. We are confident that this collaboration will result in mutual success, and we are eager to see the fruits of this shared effort.
The peer reviewers process is quick and effective, the supports from editorial office is excellent, the quality of journal is high. I would like to collabroate with Internatioanl journal of Clinical Case Reports and Reviews journal clinically in the future time.
Clinical Cardiology and Cardiovascular Interventions, we deeply appreciate the interest shown in our work and its publication. It has been a true pleasure to collaborate with you. The peer review process, as well as the support provided by the editorial office, have been exceptional, and the quality of the journal is very high, which was a determining factor in our decision to publish with you.
Clinical Cardiology and Cardiovascular Interventions I testity the covering of the peer review process, support from the editorial office, and quality of the journal.
Dear editorial department: On behalf of our team, I hereby certify the reliability and superiority of the International Journal of Clinical Case Reports and Reviews in the peer review process, editorial support, and journal quality. Firstly, the peer review process of the International Journal of Clinical Case Reports and Reviews is rigorous, fair, transparent, fast, and of high quality. The editorial department invites experts from relevant fields as anonymous reviewers to review all submitted manuscripts. These experts have rich academic backgrounds and experience, and can accurately evaluate the academic quality, originality, and suitability of manuscripts. The editorial department is committed to ensuring the rigor of the peer review process, while also making every effort to ensure a fast review cycle to meet the needs of authors and the academic community. Secondly, the editorial team of the International Journal of Clinical Case Reports and Reviews is composed of a group of senior scholars and professionals with rich experience and professional knowledge in related fields. The editorial department is committed to assisting authors in improving their manuscripts, ensuring their academic accuracy, clarity, and completeness. Editors actively collaborate with authors, providing useful suggestions and feedback to promote the improvement and development of the manuscript. We believe that the support of the editorial department is one of the key factors in ensuring the quality of the journal. Finally, the International Journal of Clinical Case Reports and Reviews is renowned for its high- quality articles and strict academic standards. The editorial department is committed to publishing innovative and academically valuable research results to promote the development and progress of related fields. The International Journal of Clinical Case Reports and Reviews is reasonably priced and ensures excellent service and quality ratio, allowing authors to obtain high-level academic publishing opportunities in an affordable manner. I hereby solemnly declare that the International Journal of Clinical Case Reports and Reviews has a high level of credibility and superiority in terms of peer review process, editorial support, reasonable fees, and journal quality. Sincerely, Rui Tao.
“The peer review process of JPMHC is quick and effective. Authors are benefited by good and professional reviewers with huge experience in the field of psychology and mental health. The support from the editorial office is very professional. People to contact to are friendly and happy to help and assist any query authors might have. Quality of the Journal is scientific and publishes ground-breaking research on mental health that is useful for other professionals in the field”.
Dr.Tania Muñoz, My experience as researcher and author of a review article in The Journal Clinical Cardiology and Interventions has been very enriching and stimulating. The editorial team is excellent, performs its work with absolute responsibility and delivery. They are proactive, dynamic and receptive to all proposals. Supporting at all times the vast universe of authors who choose them as an option for publication. The team of review specialists, members of the editorial board, are brilliant professionals, with remarkable performance in medical research and scientific methodology. Together they form a frontline team that consolidates the JCCI as a magnificent option for the publication and review of high-level medical articles and broad collective interest. I am honored to be able to share my review article and open to receive all your comments.
I am delighted to publish our manuscript entitled "A Perspective on Cocaine Induced Stroke - Its Mechanisms and Management" in the Journal of Neuroscience and Neurological Surgery. The peer review process, support from the editorial office, and quality of the journal are excellent. The manuscripts published are of high quality and of excellent scientific value. I recommend this journal very much to colleagues.
I would like to give my testimony in the support I have got by the peer review process and to support the editorial office where they were of asset to support young author like me to be encouraged to publish their work in your respected journal and globalize and share knowledge across the globe. I really give my great gratitude to your journal and the peer review including the editorial office.
I am very pleased to serve as EBM of the journal, I hope many years of my experience in stem cells can help the journal from one way or another. As we know, stem cells hold great potential for regenerative medicine, which are mostly used to promote the repair response of diseased, dysfunctional or injured tissue using stem cells or their derivatives. I think Stem Cell Research and Therapeutics International is a great platform to publish and share the understanding towards the biology and translational or clinical application of stem cells.
We are grateful for this opportunity to provide a glowing recommendation to the Journal of Psychiatry and Psychotherapy. We found that the editorial team were very supportive, helpful, kept us abreast of timelines and over all very professional in nature. The peer review process was rigorous, efficient and constructive that really enhanced our article submission. The experience with this journal remains one of our best ever and we look forward to providing future submissions in the near future.
I would like to express my gratitude towards you process of article review and submission. I found this to be very fair and expedient. Your follow up has been excellent. I have many publications in national and international journal and your process has been one of the best so far. Keep up the great work.
"We recently published an article entitled “Influence of beta-Cyclodextrins upon the Degradation of Carbofuran Derivatives under Alkaline Conditions" in the Journal of “Pesticides and Biofertilizers” to show that the cyclodextrins protect the carbamates increasing their half-life time in the presence of basic conditions This will be very helpful to understand carbofuran behaviour in the analytical, agro-environmental and food areas. We greatly appreciated the interaction with the editor and the editorial team; we were particularly well accompanied during the course of the revision process, since all various steps towards publication were short and without delay".
I am very glad to say that the peer review process is very successful and fast and support from the Editorial Office. Therefore, I would like to continue our scientific relationship for a long time. And I especially thank you for your kindly attention towards my article. Have a good day!
Dear Erica Kelsey, Editorial Coordinator of Cancer Research and Cellular Therapeutics Our team is very satisfied with the processing of our paper by your journal. That was fast, efficient, rigorous, but without unnecessary complications. We appreciated the very short time between the submission of the paper and its publication on line on your site.
Thank you very much for publishing my Research Article titled “Comparing Treatment Outcome Of Allergic Rhinitis Patients After Using Fluticasone Nasal Spray And Nasal Douching" in the Journal of Clinical Otorhinolaryngology. As Medical Professionals we are immensely benefited from study of various informative Articles and Papers published in this high quality Journal. I look forward to enriching my knowledge by regular study of the Journal and contribute my future work in the field of ENT through the Journal for use by the medical fraternity. The support from the Editorial office was excellent and very prompt. I also welcome the comments received from the readers of my Research Article.
International Journal of Clinical Case Reports and Reviews. I strongly recommend to consider submitting your work to this high-quality journal. The support and availability of the Editorial staff is outstanding and the review process was both efficient and rigorous.
Dear Agrippa Hilda, Journal of Neuroscience and Neurological Surgery, Editorial Coordinator, I trust this message finds you well. I want to extend my appreciation for considering my article for publication in your esteemed journal. I am pleased to provide a testimonial regarding the peer review process and the support received from your editorial office. The peer review process for my paper was carried out in a highly professional and thorough manner. The feedback and comments provided by the authors were constructive and very useful in improving the quality of the manuscript. This rigorous assessment process undoubtedly contributes to the high standards maintained by your journal.
As an author who has recently published in the journal "Brain and Neurological Disorders". I am delighted to provide a testimonial on the peer review process, editorial office support, and the overall quality of the journal. The peer review process at Brain and Neurological Disorders is rigorous and meticulous, ensuring that only high-quality, evidence-based research is published. The reviewers are experts in their fields, and their comments and suggestions were constructive and helped improve the quality of my manuscript. The review process was timely and efficient, with clear communication from the editorial office at each stage. The support from the editorial office was exceptional throughout the entire process. The editorial staff was responsive, professional, and always willing to help. They provided valuable guidance on formatting, structure, and ethical considerations, making the submission process seamless. Moreover, they kept me informed about the status of my manuscript and provided timely updates, which made the process less stressful. The journal Brain and Neurological Disorders is of the highest quality, with a strong focus on publishing cutting-edge research in the field of neurology. The articles published in this journal are well-researched, rigorously peer-reviewed, and written by experts in the field. The journal maintains high standards, ensuring that readers are provided with the most up-to-date and reliable information on brain and neurological disorders. In conclusion, I had a wonderful experience publishing in Brain and Neurological Disorders. The peer review process was thorough, the editorial office provided exceptional support, and the journal's quality is second to none. I would highly recommend this journal to any researcher working in the field of neurology and brain disorders.
Dear Hao Jiang, to Journal of Nutrition and Food Processing We greatly appreciate the efficient, professional and rapid processing of our paper by your team. If there is anything else we should do, please do not hesitate to let us know. On behalf of my co-authors, we would like to express our great appreciation to editor and reviewers.
This is an acknowledgment for peer reviewers, editorial board of Journal of Clinical Research and Reports. They show a lot of consideration for us as publishers for our research article “Evaluation of the different factors associated with side effects of COVID-19 vaccination on medical students, Mutah university, Al-Karak, Jordan”, in a very professional and easy way. This journal is one of outstanding medical journal.
Dr. Bernard Terkimbi Utoo, I am happy to publish my scientific work in Journal of Women Health Care and Issues (JWHCI). The manuscript submission was seamless and peer review process was top notch. I was amazed that 4 reviewers worked on the manuscript which made it a highly technical, standard and excellent quality paper. I appreciate the format and consideration for the APC as well as the speed of publication. It is my pleasure to continue with this scientific relationship with the esteem JWHCI.
Testimony of Journal of Clinical Otorhinolaryngology: work with your Reviews has been a educational and constructive experience. The editorial office were very helpful and supportive. It was a pleasure to contribute to your Journal.
Thank you most sincerely, with regard to the support you have given in relation to the reviewing process and the processing of my article entitled "Large Cell Neuroendocrine Carcinoma of The Prostate Gland: A Review and Update" for publication in your esteemed Journal, Journal of Cancer Research and Cellular Therapeutics". The editorial team has been very supportive.
Dr. Katarzyna Byczkowska My testimonial covering: "The peer review process is quick and effective. The support from the editorial office is very professional and friendly. Quality of the Clinical Cardiology and Cardiovascular Interventions is scientific and publishes ground-breaking research on cardiology that is useful for other professionals in the field.
Journal of Neuroscience and Neurological Surgery. I had the experience of publishing a research article recently. The whole process was simple from submission to publication. The reviewers made specific and valuable recommendations and corrections that improved the quality of my publication. I strongly recommend this Journal.
The peer-review process which consisted high quality queries on the paper. I did answer six reviewers’ questions and comments before the paper was accepted. The support from the editorial office is excellent.
We would like to thank the Journal of Thoracic Disease and Cardiothoracic Surgery because of the services they provided us for our articles. The peer-review process was done in a very excellent time manner, and the opinions of the reviewers helped us to improve our manuscript further. The editorial office had an outstanding correspondence with us and guided us in many ways. During a hard time of the pandemic that is affecting every one of us tremendously, the editorial office helped us make everything easier for publishing scientific work. Hope for a more scientific relationship with your Journal.
Journal of Clinical Research and Reports I would be very delighted to submit my testimonial regarding the reviewer board and the editorial office. The reviewer board were accurate and helpful regarding any modifications for my manuscript. And the editorial office were very helpful and supportive in contacting and monitoring with any update and offering help. It was my pleasure to contribute with your promising Journal and I am looking forward for more collaboration.
Journal of Women Health Care and Issues By the present mail, I want to say thank to you and tour colleagues for facilitating my published article. Specially thank you for the peer review process, support from the editorial office. I appreciate positively the quality of your journal.
Journal of Clinical Cardiology and Cardiovascular Intervention The submission and review process was adequate. However I think that the publication total value should have been enlightened in early fases. Thank you for all.
Clearly Auctoresonline and particularly Psychology and Mental Health Care Journal is dedicated to improving health care services for individuals and populations. The editorial boards' ability to efficiently recognize and share the global importance of health literacy with a variety of stakeholders. Auctoresonline publishing platform can be used to facilitate of optimal client-based services and should be added to health care professionals' repertoire of evidence-based health care resources.
