Optimization of collimator angles in dual-arc volumetric modulated arc therapy planning for whole-brain radiotherapy with hippocampus and inner ear sparing

Sun, Wu-Ji; Chen, Kunzhi; Liu, Yu; Xia, Wenming; Dong, Lihua; Shi, Yao Wu; Ge, Chao; Yang, Xu; Wang, Libo; Wang, Huidong

doi:10.1038/s41598-021-98530-7

Cited by 7 publications

(5 citation statements)

References 43 publications

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“…Within the study's parameters, the selected CRA angles did not signi cantly affect the conformity and homogeneity of radiation distribution to the target volume, as supported by non-signi cant differences (p > 0.05) in Table 2. This contrasts with Sun et al's VMAT study, where signi cant dosimetric improvements, including in the CI and HI, were observed as the collimator intersection angle (Δθ) approached 90°, emphasizing the need for precise CRA optimization in VMAT [11].…”

Section: Discussionmentioning

confidence: 57%

“…Multiple studies have investigated the impact of Collimator Rotation Angle (CRA) on optimal dose distribution in VMAT treatment plans [7][8][9][10][11][12]. Variations in dose delivery due to differences in CRA angles have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…In current VMAT, dynamic collimator rotation during beam delivery is not permitted, thus making it crucial to decide CRA for each arc before optimization [13]. Sun et al found that intersection angle of 2-arcs, Δθ, signi cantly in uence VMAT plans, with plan quality almost consistently improving as Δθ approaches 90° [11].…”

Section: Introductionmentioning

confidence: 99%

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Analyzing Collimator Rotation Angle Influence on Half-beam VMAT Outcomes for Prostate Cancer: A Comparative Approach Using Statistical and Machine Learning Methods

Kim,

Choi

et al. 2024

Preprint

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Purpose This study explores the impact of Collimator Rotation Angle (CRA) settings in Half beam Volume Modulated Arc Therapy (HVMAT) for prostate cancer treatment, focusing on dose distribution and treatment efficacy. Materials and Methods Treatment plans (Total 240) for 20 prostate cancer patients were developed using HVMAT. Different CRA settings (n = 12) were employed, specifically comparing 2-arcs and 4-arcs techniques. Data were analyzed using statistical methods and machine learning models, assessing the Mean Relative Error (MRE) across varying CRA settings. Results The analysis revealed no significant impact of CRA settings on the conformity and homogeneity of radiation distribution to the target volume. All treatment plans met the average V95% target for the prescribed dose in the Planning Target Volume (PTV). Machine learning analysis showed consistent predictive accuracy across different CRA settings, with the MRE variance within 2%. Statistical tests further supported these findings, showing no significant differences in treatment plan outcomes based on CRA variations. Conclusion The study demonstrates that CRA settings in HVMAT can be selected with considerable flexibility without compromising the effectiveness of prostate cancer treatment. The results emphasize the importance of employing multi-faceted analysis, including both traditional statistical methods and advanced machine learning techniques, in optimizing HVMAT treatment plans. Although limited by a small sample size and a specific focus on prostate cancer, the findings provide valuable insights into the clinical application of HVMAT and its potential in treatment plan optimization.

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Section: Discussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

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Analyzing Collimator Rotation Angle Influence on Half-beam VMAT Outcomes for Prostate Cancer: A Comparative Approach Using Statistical and Machine Learning Methods

Kim,

Choi

et al. 2024

Preprint

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“…The collimator angles for counterclockwise and clockwise arcs were 10° and 350°, respectively, to reduce the tongue and groove effect and the effect of interleaf leakage. 21 The anisotropic analytical algorithm (AAA) was used for the dose calculation with heterogeneous correction and a grid resolution of 2 mm. Figure 1c shows the dose distribution in the VMAT-10MV plan for the phantom with a 5 mm bolus.…”

Section: Methodsmentioning

confidence: 99%

Dosimetric investigation of whole-brain radiotherapy with helical intensity modulated radiation therapy and volumetric modulated arc therapy for scalp sparing

et al. 2023

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Objective: Intensity-modulated radiotherapy (IMRT) is a well-established radiotherapy technique for delivering radiation to cancer with high conformity while sparing the surrounding normal tissue. Two main purposes of this study are: (1) to investigate dose calculation accuracy of helical IMRT (HIMRT) and volumetric-modulated arc therapy (VMAT) on surface region and (2) to evaluate the dosimetric efficacy of HIMRT and VMAT for scalp-sparing in whole brain radiotherapy (WBRT). Methods: First, using a radiochromic film and water-equivalent phantom with three types of boluses (1, 3, 5 mm), calculation/measurement dose agreement at the surface region in the VMAT and HIMRT plans were examined. Then, HIMRT, 6MV-VMAT and 10MV-VMAT with scalp-sparing, and two conventional three-dimensional conformal radiotherapy plans (6MV-3DCRT and 10MV-3DCRT; as reference data) were created for 30 patients with brain metastasis (30 Gy/10 fractions). The mean dose to the scalp and the scalp volume receiving 24 and 30 Gy were compared. Results: The percentage dose differences between the calculation and measurement were within 7%, except for the HIMRT plan at a depth of 1 mm. The averaged mean scalp doses [Gy], V24Gy [%], and V30Gy [%] (1SD) for 6MV-3DCRT, 10MV-3DCRT, HIMRT, 6MV-VMAT, and 10MV-VMAT were [26.6 (1.1), 86.4 (7.3), 13.2 (4.2)], [25.4 (1.0), 77.8 (7.5), 13.2 (4.2)], [23.2 (1.5), 42.8 (19.2), 0.2 (0.5)], [23.6 (1.6), 47.5 (17.9), 1.2 (1.8)], and [22.7 (1.7), 36.4 (17.6), 0.7 (1.1)], respectively. Conclusion: Regarding the dose parameters, HIMRT achieved a lower scalp dose compared with 6MV-VMAT. However, the highest ability to reduce the mean scalp dose was showed in 10MV-VMAT. Advances in knowledge: Scalp-sparing WBRT using HIMRT or VMAT may prevent radiation-induced alopecia in patients with BM.

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“…For advanced radiation therapy techniques such as VMAT and RapidArc (Varian Medical System, a treatment planning and delivery method derived from VMAT) with higher delivery efficiency 1 , the radiation field in each control point is divided into multiple sub-fields with varying aperture sizes due to the movement of muti-leaf collimator leafs. During dose delivery, these sub-fields are changed over time to adjust the intensity distribution of the field 2 , 3 .…”

Section: Introductionmentioning

confidence: 99%

Application of a linear interpolation algorithm in radiation therapy dosimetry for 3D dose point acquisition

Yixiao

et al. 2023

Sci Rep

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Air-vented ion chambers are generally used in radiation therapy dosimetry to determine the absorbed radiation dose with superior precision. However, in ion chamber detector arrays, the number of array elements and their spacing do not provide sufficient spatial sampling, which can be overcome by interpolating measured data. Herein, we investigated the potential principle of the linear interpolation algorithm in volumetric dose reconstruction based on computed tomography images in the volumetric modulated arc therapy (VMAT) technique and evaluated how the ion chamber spacing and anatomical mass density affect the accuracy of interpolating new data points. Plane measurement doses on 83 VMAT treatment plans at different anatomical sites were acquired using Octavius 729, Octavius1500, and MatriXX ion chamber detector arrays, followed by the linear interpolation to reconstruct volumetric doses. Dosimetric differences in planning target volumes (PTVs) and organs at risk (OARs) between treatment planning system and reconstruction were evaluated by dose volume histogram metrics. The average percentage dose deviations in the mean dose (Dmean) of PTVs reconstructed by 729 and 1500 arrays ranged from 4.7 to 7.3% and from 1.5 to 2.3%, while the maximum dose (Dmax) counterparts ranged from 2.3 to 5.5% and from 1.6 to 7.6%, respectively. The average percentage dose/volume deviations of mixed PTVs and OARs in the abdomen/gastric and pelvic sites were 7.6%, 3.5%, and 7.2%, while mediastinum and lung plans showed slightly larger values of 8.7%, 5.1%, and 8.9% for 729, 1500, and MatriXX detector arrays, respectively. Our findings indicated that the smaller the spacing between neighbouring detectors and the more ion chambers present, the smaller the error in interpolating new data points. Anatomical regions with small local mass density inhomogeneity were associated with superior dose reconstruction. Given a large mass density difference in the various human anatomical structures and the characteristics of the linear interpolation algorithm, we suggest that an alternative data interpolation method should be used in radiotherapy dosimetry.

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Optimization of collimator angles in dual-arc volumetric modulated arc therapy planning for whole-brain radiotherapy with hippocampus and inner ear sparing

Cited by 7 publications

References 43 publications

Analyzing Collimator Rotation Angle Influence on Half-beam VMAT Outcomes for Prostate Cancer: A Comparative Approach Using Statistical and Machine Learning Methods

Analyzing Collimator Rotation Angle Influence on Half-beam VMAT Outcomes for Prostate Cancer: A Comparative Approach Using Statistical and Machine Learning Methods

Dosimetric investigation of whole-brain radiotherapy with helical intensity modulated radiation therapy and volumetric modulated arc therapy for scalp sparing

Application of a linear interpolation algorithm in radiation therapy dosimetry for 3D dose point acquisition

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