1. Quantifications of Intensity-Modulated Radiation Therapy Plan Complexities in Magnetic Resonance Image Guided Radiotherapy Systems
- Author
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Minsoo Chun, Ohyun Kwon, Jong Min Park, and Jung In Kim
- Subjects
Radiation ,Imrt plan ,medicine.diagnostic_test ,business.industry ,Health, Toxicology and Mutagenesis ,medicine.medical_treatment ,Public Health, Environmental and Occupational Health ,Magnetic resonance imaging ,Intensity-modulated radiation therapy ,Pearson product-moment correlation coefficient ,030218 nuclear medicine & medical imaging ,Radiation therapy ,03 medical and health sciences ,symbols.namesake ,Gamma analysis ,0302 clinical medicine ,Beam delivery ,030220 oncology & carcinogenesis ,symbols ,medicine ,Radiology, Nuclear Medicine and imaging ,Nuclear medicine ,business ,Mathematics - Abstract
Background: In this study, the complexities of step-and-shoot intensity-modulated radiation therapy (IMRT) plans in magnetic resonance-guided radiation therapy systems were evaluated.Materials and Methods: Overall, 194 verification plans from the abdomen, prostate, and breast sites were collected using a 60Co-based ViewRay radiotherapy system (ViewRay Inc., Cleveland, OH, USA). Various plan complexity metrics (PCMs) were calculated for each verification plan, including the modulation complexity score (MCS), plan-averaged beam area (PA), plan-averaged beam irregularity, plan-averaged edge (PE), plan-averaged beam modulation, number of segments, average area among all segments (AA/Seg), and total beam-on time (TBT). The plan deliverability was quantified in terms of gamma passing rates (GPRs) with a 1 mm/2% criterion, and the Pearson correlation coefficients between GPRs and various PCMs were analyzed.Results and Discussion: For the abdomen, prostate, and breast groups, the average GPRs with the 1 mm/2% criterion were 77.8 ± 6.0%, 79.8 ± 4.9%, and 84.7 ± 7.3%; PCMs were 0.263, 0.271, and 0.386; PAs were 15.001, 18.779, and 35.683; PEs were 1.575, 1.444, and 1.028; AA/Segs were 15.37, 19.89, and 36.64; and TBTs were 18.86, 19.33, and 5.91 minutes, respectively. The various PCMs, i.e., MCS, PA, PE, AA/Seg, and TBT, showed statistically significant Pearson correlation coefficients of 0.416, 0.627, −0.541, 0.635, and −0.397, respectively, with GPRs.Conclusion: The area-related metrics exhibited strong correlations with GPRs. Moreover, the AA/Seg metric can be used to estimate the IMRT plan accuracy without beam delivery in the 60Co-based ViewRay radiotherapy system.
- Published
- 2021