Can Online Adaptive Radiation Therapy Eliminate Intrafractional Deformation in Gastric Mucosa-Associated Lymphoid Tissue Lymphoma?

IF 3.5 3区医学 Q2 ONCOLOGY

Practical Radiation Oncology Pub Date : 2025-06-09 DOI:10.1016/j.prro.2025.05.008

Yusuke Shibayama, Hidetaka Arimura, Taka-Aki Hirose, Masanori Takaki, Jun-Ichi Fukunaga, Tadamasa Yoshitake, Toyoyuki Kato, Kousei Ishigami

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引用次数: 0

Abstract

Purpose: We hypothesized that online adaptive radiation therapy (oART) could eliminate errors associated with interfractional deformation in gastric mucosa-associated lymphoid tissue (MALT) lymphoma, but errors in intrafractional deformation remained in 6 directions (anterior, posterior, superior, inferior, left, and right). This study aimed to quantify the anisotropic deformation errors of the clinical target volume (CTV) for MALT lymphoma using oART to determine deformations in the planning target volume (PTV) margins.

Methods and materials: Thirty fractional scans from 4 consecutive patients (a total of 120 cone beam computed tomography scans) with gastric MALT lymphoma treated with oART were chosen for this retrospective study. The CTV contours were manually delineated on the pretreatment and posttreatment cone beam computed tomography images. The center-of-mass matching of the CTVs was performed following the bone anatomy matching. Systematic and random errors of intrafractional deformations of the CTV were quantified using displacement vectors between the pretreatment and posttreatment CTV surfaces for each fraction. The PTV margins for oART were anisotropically calculated using the van Herk formula: 2.5Σ + 0.7σ, accounting for intrafractional errors.

Results: For intrafractional deformation, the means of standard deviations of systematic errors ranged from 1.2 mm to 2.2 mm, whereas those of random errors ranged from 2.9 mm to 3.6 mm. The PTV margins were up to 13.1 mm in the inferior direction, whereas in other directions, they ranged from 9.7 mm to 12.8 mm. The PTV margin in integer achieved posttreatment CTV coverage for 90% of the fractions, with undercoverage volumes remaining below 0.6 cm³ in all fractions.

Conclusions: This study suggests that the impact of intrafractional CTV deformation can not be eliminated even with oART. This highlights the need to set the appropriate anisotropic PTV margins.

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在线适应性放疗能消除胃黏膜相关淋巴组织淋巴瘤的局部变形吗？

目的：我们假设在线适应性放疗（oART）可以消除胃粘膜相关淋巴组织（MALT）淋巴瘤中与分数间变形相关的误差，但分数内变形的误差仍然存在于六个方向（前、后、上、下、左、右）。本研究旨在量化MALT淋巴瘤临床靶体积（CTV）的各向异性变形误差，使用oART来确定规划靶体积（PTV）边缘的变形。方法和材料：本回顾性研究选择了连续4例经oART治疗的胃MALT淋巴瘤患者的30次分段扫描（共120次锥束计算机断层扫描（CBCT））。在处理前和处理后的CBCT图像上手工绘制CTV轮廓。骨解剖匹配后进行ctv的质心匹配。利用每个分数处理前和处理后的CTV表面之间的位移矢量量化CTV分数内变形的系统和随机误差。oART的PTV边际使用van Herk公式进行各向异性计算：2.5Σ+0.7σ，考虑分数内误差。结果：对于分数内变形，系统误差的标准差均值为1.2 mm ~ 2.2 mm，随机误差的标准差均值为2.9 mm ~ 3.6 mm。下向PTV边缘最大13.1 mm，其他方向PTV边缘在9.7 ~ 12.8 mm之间。整型PTV余量在90%的馏分中实现了处理后CTV覆盖，所有馏分的未覆盖体积均保持在0.6 cm³以下。结论：本研究提示，即使采用oART，仍不能消除分数段内CTV变形对oART误差的影响。这突出了设置适当的各向异性PTV边界的必要性。

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

Practical Radiation Oncology Medicine-Radiology, Nuclear Medicine and Imaging

CiteScore

5.20

自引率

6.10%

发文量

177

审稿时长

34 days

期刊介绍： The overarching mission of Practical Radiation Oncology is to improve the quality of radiation oncology practice. PRO''s purpose is to document the state of current practice, providing background for those in training and continuing education for practitioners, through discussion and illustration of new techniques, evaluation of current practices, and publication of case reports. PRO strives to provide its readers content that emphasizes knowledge "with a purpose." The content of PRO includes: Original articles focusing on patient safety, quality measurement, or quality improvement initiatives Original articles focusing on imaging, contouring, target delineation, simulation, treatment planning, immobilization, organ motion, and other practical issues ASTRO guidelines, position papers, and consensus statements Essays that highlight enriching personal experiences in caring for cancer patients and their families.