Impact of bulk density assignment of bone on MRI-based abdominal region radiotherapy planning for MR-linac workflow.

IF 2 4区医学 Q3 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Journal of Applied Clinical Medical Physics Pub Date : 2025-02-25 DOI:10.1002/acm2.70059

Kota Abe, Masato Tsuneda, Yukio Fujita, Yukinao Abe, Takashi Uno

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引用次数: 0

Abstract

Purpose: The purpose of the present study was to evaluate the impact of bone relative electron density (rED) assignment on radiotherapy planning for the abdominal region.

Methods: Twenty patients who received abdominal radiotherapy using MR-Linac and underwent magnetic resonance imaging (MRI) and computed tomography (CT) simulation were analyzed. The reference plan (RP) was established using both CT and MR image sets (RP_CT and RP_MRI). The RP_MRI utilized the bulk density method. The recalculated RPs derived from various rED assignment methods were evaluated for comparison on both datasets. The RPs were recalculated by excluding rED assignment for bones (scenario A). Based on the International Commission on Radiation Units and Measurements report, lung contours were assigned rED of 0.258, and body contours were assigned 1.000 (scenario B) and 1.019 (scenario C). Dose volume histogram (DVH) differences between the three recalculated scenarios and RPs were evaluated. D95, D99, and D1cc were evaluated for target volumes, including gross tumor volume, internal target volume, and planning target volume. DVH parameters, including D1cc for each abdominal organ at risk (OAR) and the mean dose to the liver and kidneys, were evaluated. Three-dimensional local gamma analysis was conducted to assess dose distribution differences between the three recalculated scenarios and RPs.

Results: In all scenarios of the CT- and MRI-based validation, the average gamma pass rates (2%/2 mm) were higher than 95%. In the CT-based validation, all target DVHs across the 20 patients showed that none exceeded 2% error in scenario A, whereas 2% and 14% exceeded the threshold in scenarios B and C, respectively. For OARs in CT and MRI-based validation, absolute maximum dose differences when compared with those of the RP were 0.19 Gy and 0.22 Gy, respectively, in scenario A.

Conclusion: Excluding bone rED considerations in abdominal treatment planning may not yield notable clinical differences.

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骨容重分配对mri -linac工作流程中基于mri的腹部放疗计划的影响。

目的：本研究的目的是评估骨相对电子密度（rED）分配对腹部放射治疗计划的影响。方法：对20例经MR-Linac进行腹部放射治疗并行磁共振成像（MRI）和计算机断层扫描（CT）模拟的患者进行分析。采用CT和MR图像集（RP_CT和RP_MRI）建立参考计划（RP）。RP_MRI采用体积密度法。在两个数据集上对不同rED分配方法得到的重新计算的rp进行比较评估。重新计算RPs，排除骨骼的rED分配（情景A）。根据国际辐射单位和测量委员会的报告，肺轮廓的rED分配为0.258，身体轮廓的rED分配为1.000（情景B）和1.019（情景C）。评估三种重新计算的情景和RPs之间的剂量-体积直方图（DVH）差异。评估D95、D99和D1cc靶体积，包括肿瘤总体积、内部靶体积和计划靶体积。评估DVH参数，包括每个腹部危险器官（OAR）的D1cc和肝脏和肾脏的平均剂量。进行三维局部伽玛分析，以评估三种重新计算情景与rp之间的剂量分布差异。结果：在所有基于CT和mri的验证方案中，平均伽马通过率（2%/ 2mm）均高于95%。在基于ct的验证中，20例患者的所有目标dvh在场景A中都没有超过2%的误差，而在场景B和C中分别有2%和14%的误差超过阈值。对于基于CT和mri验证的OARs，在情景a中，与RP相比，绝对最大剂量差异分别为0.19 Gy和0.22 Gy。结论：在腹部治疗计划中排除骨红色因素可能不会产生显着的临床差异。

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

Journal of Applied Clinical Medical Physics 医学-核医学

CiteScore

3.60

自引率

19.00%

发文量

331

审稿时长

3 months

期刊介绍： Journal of Applied Clinical Medical Physics is an international Open Access publication dedicated to clinical medical physics. JACMP welcomes original contributions dealing with all aspects of medical physics from scientists working in the clinical medical physics around the world. JACMP accepts only online submission. JACMP will publish: -Original Contributions: Peer-reviewed, investigations that represent new and significant contributions to the field. Recommended word count: up to 7500. -Review Articles: Reviews of major areas or sub-areas in the field of clinical medical physics. These articles may be of any length and are peer reviewed. -Technical Notes: These should be no longer than 3000 words, including key references. -Letters to the Editor: Comments on papers published in JACMP or on any other matters of interest to clinical medical physics. These should not be more than 1250 (including the literature) and their publication is only based on the decision of the editor, who occasionally asks experts on the merit of the contents. -Book Reviews: The editorial office solicits Book Reviews. -Announcements of Forthcoming Meetings: The Editor may provide notice of forthcoming meetings, course offerings, and other events relevant to clinical medical physics. -Parallel Opposed Editorial: We welcome topics relevant to clinical practice and medical physics profession. The contents can be controversial debate or opposed aspects of an issue. One author argues for the position and the other against. Each side of the debate contains an opening statement up to 800 words, followed by a rebuttal up to 500 words. Readers interested in participating in this series should contact the moderator with a proposed title and a short description of the topic