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Purpose: To demonstrate the impact of modulation indices and plan parameters on the gamma passing rates (GPR) of patient-specific quality assurance of standard and stereotactic volumetric modulated arc therapy (VMAT) plans.
Methods: A total of 758 patients' QA plans were utilized, including standard VMAT plans with Trilogy (n = 87, group A) and TreuBeam STx (n = 332, group B), and 339 stereotactic VMAT plans with TrueBeam STx (group C). Modulation indices were obtained considering the speed and acceleration of the multileaf collimator (MLC) (MI, MI), and MLC, gantry speed, and dose rate changes (MI). The mean aperture size (MA), monitor unit (MU), and amount of jaw tracking (%JT) were acquired. Gamma analysis was performed with 2 mm/2% and 1 mm/2% for the standard and stereotactic VMAT plans, respectively. Statistical analyses were performed to investigate the correlation between modulation index/plan parameters and GPR.
Results: Spearman's rank correlation to GPRs with MI, MI, and MI, were -0.44, -0.45, and -0.46 for group A; -0.39, -0.37, and -0.38 for group B; and -0.04, -0.11, and -0.10 for group C, respectively. While MU and MA showed significant correlations in all groups, %JT showed a significant correlation only with stereotactic VMAT plans. The most influential parameter combinations were MU-MA (r = 0.50), MI-%JT (r = 0.43), and MU-%JT (r = 0.38) for groups A, B, and C, respectively.
Conclusions: MLC modulation mostly affected the GPR in the delivery of standard VMAT plans, while MU and %JT showed more importance in stereotactic VMAT plans.
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http://dx.doi.org/10.1016/j.ejmp.2019.05.005 | DOI Listing |
Rep Pract Oncol Radiother
August 2025
Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland.
Background: To compare doses deposited to the liver during right breast radiotherapy with static and dynamic radiotherapy techniques. The second aim was to introduce the liver load index (LLI), a novel index developed to estimate radiation exposure to the liver prior to treatment selection.
Materials And Methods: We prepared radiotherapy treatment plans for ten patients with right breast cancer.
Rep Pract Oncol Radiother
August 2025
Hospital General de Mexico "Dr Eduardo Liceaga", Mexico City, Mexico.
Background: Paragangliomas are highly vascularized tumours that have benign histology, with malignant dissemination being infrequent (< 5%). Surgery is the only option offering complete resection; however, there is significant morbidity. Treatment with radiotherapy (RT) offers good results in controlling the disease.
View Article and Find Full Text PDFMed Dosim
September 2025
Department of Radiological Technology, Faculty of Health Science, Juntendo University, Tokyo, 113-0034, Japan.
This study investigated hybrid volumetric-modulated arc therapy (H-VMAT) for the treatment of nonsmall cell lung cancer (NSCLC) by classifying patients based on the tumor location (left or right and upper, middle or low) and planning target volume (PTV) (less than average or greater than average) to determine the optimal VMAT dose ratio by dividing the prescription dose used for H-VMAT planning. The following treatment plans comprising four-field conformal irradiation were created for 51 patients with NSCLC: VMAT with one full arc (f-VMAT); VMAT with two partial arcs (p-VMAT); and hybrid plans. Hybrid plans comprised a combination of f-VMAT and three-dimensional conformal radiation therapy (3D-CRT; fH-VAMT) as well as a combination of p-VMAT and 3D-CRT (pH-VMAT).
View Article and Find Full Text PDFFront Oncol
August 2025
Department of Radiation Oncology, The Affiliated Huizhou Hospital, Guangzhou Medical University, Huizhou, China.
Background: Breast cancer is the foremost malignancy threatening female health. This study aimed to compare the dosimetric performance of Halcyon 3.0 and TrueBeam in Volumetric Modulated Arc Therapy (VMAT) planning for breast cancer.
View Article and Find Full Text PDFJ Biomed Phys Eng
August 2025
Department of Medical Physics, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Background: Modern radiotherapy techniques can destroy tumors with less harm to surrounding normal tissues. Normal Tissue Complication Probability (NTCP) models are useful to evaluate treatment plans.
Objective: This study aimed to use the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) program to evaluate dose-volume indicators and radiobiological parameters for complications of the rectum and bladder in prostate cancer patients undergoing pelvic radiotherapy.