Francesco Tortorelli Tortorelli, Cristian Borrazzo, Marica Masi, Maria Rago, Randa El Gawhary, Claudio Properzi, Domenico Marchesano, Gianmarco Grimaldi, Federico Bianciardi, Ivan Annessi, Annamaria Dipalma, Maria Valentino, Laura Verna, Giuseppina Chiarello, Wolfango Plastino, Piercarlo Gentile
{"title":"A quantification of the electron return effect using Monte Carlo simulations and experimental measurements for the MRI-linac.","authors":"Francesco Tortorelli Tortorelli, Cristian Borrazzo, Marica Masi, Maria Rago, Randa El Gawhary, Claudio Properzi, Domenico Marchesano, Gianmarco Grimaldi, Federico Bianciardi, Ivan Annessi, Annamaria Dipalma, Maria Valentino, Laura Verna, Giuseppina Chiarello, Wolfango Plastino, Piercarlo Gentile","doi":"10.1088/2057-1976/ad8ce3","DOIUrl":null,"url":null,"abstract":"<p><p>The integration of magnetic resonance (MR) imaging and linear accelerators into hybrid treatment systems has made MR-guided radiation therapy a clinical reality. This work aims to evaluate the influence of the Electron Return Effect (ERE) on the dose distributions.
This study was conducted using MRIdian (ViewRay, Cleveland, Ohio) system. Monte-Carlo simulations (MCs) and experimental measurements with EBT3 Gafchromic films were performed to investigate the dose distribution in a slab water phantom with and without a 2-cm air gap. Plus, MCs took into account different field sizes and a lung gap. A gamma analysis compared calculated versus measured dose distributions.
The MCs have shown an increase of the ERE with the radiation field size both in Percent Depth Dose (PDD) and crossline direction. As concerns to the PDD direction, the smallest field for which there was a significant dose accumulation was 4.15x4.15 cm2 both for air-gap (13.5%) and lung-gap (3.3%). The largest field for which there was a significant dose accumulation was 24.07x24.07 cm2 both for air-gap (39.7%) and lung-gap (4.9%). Instead for the crossline direction, the smallest field for which there was a significant dose accumulation was 2.49x2.49 cm2 both for air-gap (8.6% ) and lung-gap (0.5%). The largest field for which there was a significant dose accumulation was 24.07x24.07 cm2 both for air-gap (46.2%) and lung-gap (4.2%).
PDD and crossline profiles showed good agreement with a gamma-passing rate higher than 91.15% for 2%/2mm. The ERE can be adequately calculated by MC dose calculation platform available in the MRIdian Treatment Planning System. The MCs show an increase of the ERE directly proportional with the radiation field size. Good agreement was observed between the experimental measurements and calculated dose distributions.</p>","PeriodicalId":8896,"journal":{"name":"Biomedical Physics & Engineering Express","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biomedical Physics & Engineering Express","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1088/2057-1976/ad8ce3","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING","Score":null,"Total":0}
引用次数: 0
Abstract
The integration of magnetic resonance (MR) imaging and linear accelerators into hybrid treatment systems has made MR-guided radiation therapy a clinical reality. This work aims to evaluate the influence of the Electron Return Effect (ERE) on the dose distributions.
This study was conducted using MRIdian (ViewRay, Cleveland, Ohio) system. Monte-Carlo simulations (MCs) and experimental measurements with EBT3 Gafchromic films were performed to investigate the dose distribution in a slab water phantom with and without a 2-cm air gap. Plus, MCs took into account different field sizes and a lung gap. A gamma analysis compared calculated versus measured dose distributions.
The MCs have shown an increase of the ERE with the radiation field size both in Percent Depth Dose (PDD) and crossline direction. As concerns to the PDD direction, the smallest field for which there was a significant dose accumulation was 4.15x4.15 cm2 both for air-gap (13.5%) and lung-gap (3.3%). The largest field for which there was a significant dose accumulation was 24.07x24.07 cm2 both for air-gap (39.7%) and lung-gap (4.9%). Instead for the crossline direction, the smallest field for which there was a significant dose accumulation was 2.49x2.49 cm2 both for air-gap (8.6% ) and lung-gap (0.5%). The largest field for which there was a significant dose accumulation was 24.07x24.07 cm2 both for air-gap (46.2%) and lung-gap (4.2%).
PDD and crossline profiles showed good agreement with a gamma-passing rate higher than 91.15% for 2%/2mm. The ERE can be adequately calculated by MC dose calculation platform available in the MRIdian Treatment Planning System. The MCs show an increase of the ERE directly proportional with the radiation field size. Good agreement was observed between the experimental measurements and calculated dose distributions.
期刊介绍:
BPEX is an inclusive, international, multidisciplinary journal devoted to publishing new research on any application of physics and/or engineering in medicine and/or biology. Characterized by a broad geographical coverage and a fast-track peer-review process, relevant topics include all aspects of biophysics, medical physics and biomedical engineering. Papers that are almost entirely clinical or biological in their focus are not suitable. The journal has an emphasis on publishing interdisciplinary work and bringing research fields together, encompassing experimental, theoretical and computational work.