Test for geometric accuracy of imaging for magnetic resonance-guided radiotherapy(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2024年第8期
- Page:
- 925-930
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Test for geometric accuracy of imaging for magnetic resonance-guided radiotherapy
- Author(s):
- ZHU Ji; CHEN Xinyuan; QIN Shirui; YANG Zhuanbo; CAO Ying; MEN Kuo; DAI Jianrong
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Keywords:
- Keywords: magnetic resonance image radiotherapy geometric distortion segmentation accuracy
- PACS:
- R319；R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2024.08.001
- Abstract:
- Abstract: Objective To evaluate the effects of the multiple factors especially image geometric accuracy of the imaging system on the segmentations of target areas and organs-at-risk. Methods The study used phantoms to test the imaging performance of the 1.5T magnetic resonance (MR) linear accelerator system, including the assessments of MR image geometric distortion and the segmentation errors caused by factors such as image geometric distortion. Model 604-GS large field MR image distortion phantom was used to explore the geometric distortion of the MR images for MR-guided radiotherapy and CIRS Model 008z upper abdominal phantom was used to analyze the segmentation errors of target areas and organs-at-risk. Results The average geometric distortion and maximum distortion of 3D T1WI-FFE images vs 3D T2WI-TSE images were 0.54 mm vs 0.53 mm and 1.96 mm vs 1.68 mm, respectively and the control points of the large distortions were distributed at the edges of the phantom, which was consistent with the MR imaging characteristics previously reported. Compared with CT-based segmentation contour, the MDA was 1.17 mm and DSC was 0.91 for 3D T1WI-FFE, while MDA was 0.86 mm and DSC was 0.94 for 3D T2WI-TSE. Conclusion The study quantitatively assesses the geometric accuracy of the imaging system for MR-guided radiotherapy. The phantom-based contour analysis reveals that with CT image as gold standard, the segmentation error in MRI images meets the clinical requirements, and that 3D T2WI-TSE image is advantageous over 3D T1WI-FFE image in segmentation accuracy.
Last Update: 2024-08-31