胰腺癌立体定向体部放射治疗中短期胃肠道运动及其对剂量学参数影响的评估
Evaluation of short-term gastrointestinal motion and its impact on dosimetric parameters in stereotactic body radiation therapy for pancreatic cancer.
作者信息
Uchinami Yusuke, Kanehira Takahiro, Fujita Yoshihiro, Miyamoto Naoki, Yokokawa Kohei, Koizumi Fuki, Shido Motoyasu, Takahashi Shuhei, Otsuka Manami, Yasuda Koichi, Taguchi Hiroshi, Nakazato Keiji, Kobashi Keiji, Katoh Norio, Aoyama Hidefumi
机构信息
Department of Radiation Oncology, Hokkaido University Faculty of Medicine and Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan.
Department of Medical Physics, Hokkaido University Hospital, North 14 West 5, Kita-ku, Sapporo, Hokkaido 060-8648, Japan.
出版信息
Clin Transl Radiat Oncol. 2023 Jan 7;39:100576. doi: 10.1016/j.ctro.2023.100576. eCollection 2023 Mar.
BACKGROUND
The aim of this study is to quantify the short-term motion of the gastrointestinal tract (GI-tract) and its impact on dosimetric parameters in stereotactic body radiation therapy (SBRT) for pancreatic cancer.
METHODS
The analyzed patients were eleven pancreatic cancer patients treated with SBRT or proton beam therapy. To ensure a fair analysis, the simulation SBRT plan was generated on the planning CT in all patients with the dose prescription of 40 Gy in 5 fractions. The GI-tract motion (stomach, duodenum, small and large intestine) was evaluated using three CT images scanned at spontaneous expiration. After fiducial-based rigid image registration, the contours in each CT image were generated and transferred to the planning CT, then the organ motion was evaluated. Planning at risk volumes (PRV) of each GI-tract were generated by adding 5 mm margins, and the volume receiving at least 33 Gy (V) < 0.5 cm was evaluated as the dose constraint.
RESULTS
The median interval between the first and last CT scans was 736 s (interquartile range, IQR:624-986). To compensate for the GI-tract motion based on the planning CT, the necessary median margin was 8.0 mm (IQR: 8.0-10.0) for the duodenum and 14.0 mm (12.0-16.0) for the small intestine. Compared to the planned V with the worst case, the median V in the PRV of the duodenum significantly increased from 0.20 cm (IQR: 0.02-0.26) to 0.33 cm (0.10-0.59) at Wilcoxon signed-rank test (p = 0.031).
CONCLUSION
The short-term motions of the GI-tract lead to high dose differences.
背景
本研究的目的是量化胃肠道（GI 道）的短期运动及其对胰腺癌立体定向体部放射治疗（SBRT）中剂量学参数的影响。
方法
分析的患者为 11 例接受 SBRT 或质子束治疗的胰腺癌患者。为确保公平分析，在所有患者的计划 CT 上生成模拟 SBRT 计划，剂量处方为 40 Gy，分 5 次照射。使用在自主呼气时扫描的三张 CT 图像评估 GI 道运动（胃、十二指肠、小肠和大肠）。在基于基准的刚性图像配准后，在每张 CT 图像上生成轮廓并转移到计划 CT，然后评估器官运动。通过添加 5 mm 边界生成每个 GI 道的计划危及器官体积（PRV），并将接受至少 33 Gy（V）<0.5 cm³的体积评估为剂量约束。
结果
第一次和最后一次 CT 扫描之间的中位间隔为 736 s（四分位间距，IQR：624 - 986）。为基于计划 CT 补偿 GI 道运动，十二指肠所需的中位边界为 8.0 mm（IQR：8.0 - 10.0），小肠为 14.0 mm（12.0 - 16.0）。与最坏情况的计划 V 相比，在 Wilcoxon 符号秩检验中，十二指肠 PRV 中的中位 V 从 0.20 cm³（IQR：0.02 - 0.26）显著增加到 0.33 cm³（0.10 - 0.59）（p = 0.031）。
结论
GI 道的短期运动导致高剂量差异。
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