{"title":"Evaluation of dynamic accuracy and latency of a surface-guided radiotherapy system.","authors":"Ryohei Yamauchi, Fumihiro Tomita","doi":"10.1007/s12194-024-00866-y","DOIUrl":null,"url":null,"abstract":"<p><p>The aim of this study is to evaluate the dynamic accuracy and latency of the surface-guided radiotherapy (SGRT) system using TrueBeam and AlignRT in compliance with SGRT guidelines. Beam characteristics-flatness, symmetry, beam quality, and output-were compared between gated and nongated beams using a two-dimensional ionization chamber array and a Farmer-type chamber. Dynamic accuracy was assessed using a moving platform and breast phantom, with measurements taken for various shift values (5, 10, 30 mm), region-of-interest (ROI) shapes, reference-surface image types (DICOM and capture), surface resolutions, and room illuminations. Latency due to differences in frame rates was evaluated using radiochromic film, calculated from position displacements of profiles at two speeds. Differences in beam characteristics between gated and nongated beams were within 0.1%. Dynamic accuracy showed minimal dependence on settings, with deviations of < 1 mm for a 10-mm shift. A maximum displacement of 1.9 mm was observed with a 30-mm shift at the body ROI. Beam-on latency at 12, 16, 25, and 35 frames per second was 253.2 ± 21.9, 225.7 ± 33.7, 177.1 ± 43.0, and 112.4 ± 29.2 ms, respectively, with similar trends for beam-off latency. This study is the first to evaluate the dynamic accuracy of the TrueBeam and AlignRT system under SGRT-specific settings. While accuracy was generally maintained (< 1 mm), ROI shape significantly impacted results. Latency results indicate that certain frame rates may not meet guideline limits, underscoring the need for careful SGRT system use in clinical applications.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7000,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Radiological Physics and Technology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s12194-024-00866-y","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 aim of this study is to evaluate the dynamic accuracy and latency of the surface-guided radiotherapy (SGRT) system using TrueBeam and AlignRT in compliance with SGRT guidelines. Beam characteristics-flatness, symmetry, beam quality, and output-were compared between gated and nongated beams using a two-dimensional ionization chamber array and a Farmer-type chamber. Dynamic accuracy was assessed using a moving platform and breast phantom, with measurements taken for various shift values (5, 10, 30 mm), region-of-interest (ROI) shapes, reference-surface image types (DICOM and capture), surface resolutions, and room illuminations. Latency due to differences in frame rates was evaluated using radiochromic film, calculated from position displacements of profiles at two speeds. Differences in beam characteristics between gated and nongated beams were within 0.1%. Dynamic accuracy showed minimal dependence on settings, with deviations of < 1 mm for a 10-mm shift. A maximum displacement of 1.9 mm was observed with a 30-mm shift at the body ROI. Beam-on latency at 12, 16, 25, and 35 frames per second was 253.2 ± 21.9, 225.7 ± 33.7, 177.1 ± 43.0, and 112.4 ± 29.2 ms, respectively, with similar trends for beam-off latency. This study is the first to evaluate the dynamic accuracy of the TrueBeam and AlignRT system under SGRT-specific settings. While accuracy was generally maintained (< 1 mm), ROI shape significantly impacted results. Latency results indicate that certain frame rates may not meet guideline limits, underscoring the need for careful SGRT system use in clinical applications.
期刊介绍:
The purpose of the journal Radiological Physics and Technology is to provide a forum for sharing new knowledge related to research and development in radiological science and technology, including medical physics and radiological technology in diagnostic radiology, nuclear medicine, and radiation therapy among many other radiological disciplines, as well as to contribute to progress and improvement in medical practice and patient health care.