Evaluation of intra-fractional anatomical variations during liver MRgART under abdominal compression using optical flow calculation.

IF 6.4 1区医学 Q1 ONCOLOGY

International Journal of Radiation Oncology Biology Physics Pub Date : 2025-03-15 DOI:10.1016/j.ijrobp.2025.03.014

Takanori Adachi, Nobutaka Mukumoto, Haruo Inokuchi, Nobunari Hamaura, Mutsumi Yamagishi, Mai Sakagami, Naoki Mukumoto, Kenji Hayashi, Ryo Ogino, Mitsuhiro Nakamura, Keiko Shibuya

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引用次数: 0

Abstract

Purpose: To investigate the intra-fractional anatomical variations during liver magnetic resonance-guided adaptive radiotherapy (MRgART) under abdominal compression (AC) using optical flow calculations.

Methods: This study included 27 consecutive patients who underwent liver MRgART under AC. Overall, 387,566 slices from 145 single-slice cine MR series obtained from 29 different treatment plans were analyzed in the coronal and sagittal planes through tumor centers. After defining the square regions as 12 pixels centered on the isocenter for the tumor and 8 pixels between the inspiratory and expiratory phases, excluding the lung/liver boundary for the diaphragm, the vectors were calculated using Farnebäck optical flow. The intra-fractional superior-inferior (SI) motion range and the root-mean-square error (RMSE) between the position of the tumor and the diaphragm in the coronal (SI_coronal and RMSE_coronal) and sagittal planes (SI_sagittal and RMSE_sagittal) were classified according to the Couinaud-based tumor regions (segment I+IV, II+III, V+VIII, and VI+VII). Statistical significance was determined using the Wilcoxon signed-rank test with Holm-Bonferroni corrections (p < 0.05).

Results: The median SI_coronal and SI_sagittal motion ranges of the tumor were 6.1 mm (range, 1.5-18.0 mm) and 8.1 mm (range, 1.0-21.0 mm), respectively (p < 0.05). When classified according to tumor location, segment VI+VII showed the largest difference, with the median SI_coronal and SI_sagittal motion ranges of 6.5 mm (range, 2.3-17.7 mm) and 10.6 mm (range, 4.8-21.0 mm), respectively (p < 0.05). The median RMSE_coronal and RMSE_sagittal values were the largest in segment VI+VII, showing significant differences of 2.6 mm and 2.2 mm, respectively (p < 0.05). These differences were due to the sliding motion of dorsally located tumors.

Conclusions: Optical flow analysis underestimated the SI motion range in the coronal plane compared with that in the sagittal plane during liver MRgART under AC. Tumor motion should be monitored in the sagittal plane, considering sliding motion of the liver, with individualized margins according to tumor location.

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目的：利用光流计算研究腹部加压（AC）下肝脏磁共振引导自适应放射治疗（MRgART）过程中的分段内解剖学变化：本研究纳入了27名连续接受腹腔压迫下肝脏磁共振引导自适应放疗（MRgART）的患者。在冠状面和矢状面分析了从 29 种不同治疗方案中获得的 145 个单片 cine MR 系列中的 387,566 个切片，这些切片穿过肿瘤中心。在将方形区域定义为以肿瘤等中心为中心的 12 个像素和吸气期与呼气期之间的 8 个像素（膈肌的肺/肝边界除外）后，使用 Farnebäck 光流计算了矢量。根据基于 Couinaud 的肿瘤区域（I+IV 段、II+III 段、V+VIII 段和 VI+VII 段）对肿瘤和膈肌在冠状面（SIcoronal 和 RMSEcoronal）和矢状面（SIsagittal 和 RMSEsagittal）位置之间的分内上-下（SI）运动范围和均方根误差（RMSE）进行分类。统计意义采用 Wilcoxon 符号秩检验和 Holm-Bonferroni 校正（P < 0.05）：肿瘤的中位SI冠状位和SI矢状位运动范围分别为6.1毫米（范围为1.5-18.0毫米）和8.1毫米（范围为1.0-21.0毫米）（P < 0.05）。根据肿瘤位置分类时，VI+VII节段的差异最大，中位SI冠状位和SI矢状位的运动范围分别为6.5毫米（范围为2.3-17.7毫米）和10.6毫米（范围为4.8-21.0毫米）（P < 0.05）。冠状面和矢状面的中位 RMSE 值在第 VI+VII 节段最大，分别为 2.6 毫米和 2.2 毫米，差异显著（P < 0.05）。这些差异是由于背侧肿瘤的滑动运动造成的：结论：在 AC 下进行肝脏 MRgART 时，与矢状面相比，光学血流分析低估了冠状面上的 SI 运动范围。考虑到肝脏的滑动运动，应在矢状面上监测肿瘤的运动，并根据肿瘤的位置设置个性化的边缘。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Radiation Oncology Biology Physics 医学-核医学

CiteScore

11.00

自引率

7.10%

发文量

2538

审稿时长

6.6 weeks

期刊介绍： International Journal of Radiation Oncology • Biology • Physics (IJROBP), known in the field as the Red Journal, publishes original laboratory and clinical investigations related to radiation oncology, radiation biology, medical physics, and both education and health policy as it relates to the field. This journal has a particular interest in original contributions of the following types: prospective clinical trials, outcomes research, and large database interrogation. In addition, it seeks reports of high-impact innovations in single or combined modality treatment, tumor sensitization, normal tissue protection (including both precision avoidance and pharmacologic means), brachytherapy, particle irradiation, and cancer imaging. Technical advances related to dosimetry and conformal radiation treatment planning are of interest, as are basic science studies investigating tumor physiology and the molecular biology underlying cancer and normal tissue radiation response.