Simulation Study of Upright Prostate Radiation Therapy: Comparison of Upright and Supine Anatomy and Dose-Volumetric Factors

IF 3.5 3区医学 Q2 ONCOLOGY

Practical Radiation Oncology Pub Date : 2025-04-30 DOI:10.1016/j.prro.2025.04.007

Kohei Oguma MSc , Yoshitake Yamada MD, PhD , Naoyoshi Koike MD, PhD , Junichi Fukada MD, PhD , Minoru Yamada PhD , Yoichi Yokoyama MD, PhD , Atsuya Takeda MD, PhD , Naoyuki Shigematsu MD, PhD , Masahiro Jinzaki MD, PhD

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引用次数: 0

Abstract

Purpose

This study aimed to assess the feasibility of upright radiation therapy for prostate cancer, compared to conventional supine radiation therapy, by quantitatively evaluating anatomic changes and their dosimetric impact through treatment planning simulations based on paired upright and supine positioning computed tomography (CT) images.

Methods and Materials

This study compared pelvic organ anatomies and dose distributions, in hypothetical prostate cancer patients, between upright and supine prostate radiation therapy using paired CT images from asymptomatic volunteers. Anatomic changes in pelvic organ position, shape, volume, and rectal gas were quantitatively evaluated. Prostate radiation therapy was simulated on these CT images for volumetric modulated arc therapy with a prescribed dose of 60 Gy in 20 fractions. Dosimetric comparisons were performed using dose-volume histogram parameters based on a clinical protocol.

Results

Fifty-one asymptomatic volunteers were registered. Compared to the supine position, pelvic organs in the upright position moved inferiorly (prostate: 2.8 mm ± 5.2, rectum: 2.9 mm ± 5.8, bladder: 3.7 mm ± 6.9, bowel: 25.2 mm ± 18.6; all P < .001). Rectal gas moved superiorly (4.8 mm ± 11.9; P = .004) and posteriorly (10.7 mm ± 23.5; P = .008). All dose-volume histogram parameters met the dose constraints, and the dose distributions of the upright and supine plans were clinically comparable in terms of organ-at-risk sparing and target coverage (P > .05). In some cases, the rectum curved more posteriorly in the upright position, allowing better sparing of high-dose areas, and the bladder moved inferiorly while expanding in the anterior-posterior direction in the upright position, preventing the small bowel from dropping into the radiation field.

Conclusions

Our treatment planning simulation showed that upright radiation therapy for prostate cancer is feasible with a dose distribution comparable to that of conventional supine radiation therapy, despite significant anatomic changes in pelvic organ positioning between the upright and supine patient positions.

查看原文本刊更多论文

直立前列腺放射治疗的模拟研究：直立和仰卧解剖及剂量-体积因素的比较。

目的：通过对直立和仰卧位计算机断层扫描（CT）图像进行治疗计划模拟，定量评估前列腺癌直立放射治疗与传统仰卧放射治疗的可行性，评估其解剖变化及其剂量学影响。材料和方法：本研究使用来自无症状志愿者的配对CT图像，比较假设前列腺癌患者的直立和仰卧前列腺放疗的盆腔器官解剖和剂量分布。定量评估盆腔器官位置、形状、体积和直肠气体的解剖变化。在这些CT图像上模拟前列腺放射治疗，进行体积调制电弧治疗（VMAT），规定剂量为60 Gy，分为20份。采用基于临床方案的剂量-体积直方图（DVH）参数进行剂量学比较。结果：共登记51名无症状志愿者。与仰卧位相比，直立位盆腔器官下移(前列腺：2.8 mm±5.2，直肠：2.9 mm±5.8，膀胱：3.7 mm±6.9，肠：25.2 mm±18.6；P < 0.001)。直肠气上移(4.8 mm±11.9；P = .004)和后侧(10.7 mm±23.5；P = .008)。所有DVH参数均满足剂量限制，并且直立和仰卧方案的剂量分布在器官危险保护和靶覆盖方面具有临床可比性（P < 0.05）。部分病例在直立位时直肠更后弯，可以更好地保留高剂量区域；在直立位时，膀胱在前后方向扩张时向下移动，防止小肠落入辐射场。结论：我们的治疗计划模拟显示，直立放疗治疗前列腺癌是可行的，其剂量分布与传统仰卧位放疗相当，尽管直立和仰卧位患者的盆腔器官位置有明显的解剖变化。

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.