Department of Radiation Oncology, Asahi University Hospital, 3-23 Hashimoto-cho, Gifu City, Gifu, 500-8523, Japan.
Department of Oral and Maxillofacial Surgery, Asahi University Hospital, 3-23 Hashimoto-cho, Gifu City, Gifu, 500-8523, Japan.
Radiat Oncol. 2022 Jul 31;17(1):136. doi: 10.1186/s13014-022-02107-1.
In clinical practice, the organs at risk (OARs) should be carefully determined when performing pancreatic stereotactic body radiotherapy (SBRT). We conducted a simulation study to examine the effect of the stomach size on the radiation dose to the OARs when performing pancreatic SBRT.
Twenty-five cases were included in this study. Pancreatic head and body tumors were 2-cm-sized pseudotumors, which were included as gross target volume (GTV) contours. The stomach, pancreas, small intestine, liver, kidneys, and spinal cord were considered as the OARs. The prescription dose for planning target volume (PTV) was 40 Gy/5fx, and the dose limit for the OARs was determined. The dose to X% of the OAR volume at X values of 0.1, 5.0, and 10.0 cc (DX) and the percentage of the OAR volume that received more than X Gy were recorded.
In terms of the radiation dose to the pancreatic body tumors, the stomach size was positively correlated with a dose of D10cc [correlation coefficient (r) = 0.5516) to the stomach. The r value between the radiation dose to the pancreatic head tumor and the stomach size was 0.3499. The stomach size and radiation dose to the head and body of the pancreas were positively correlated (pancreatic head D10cc: r = 0.3979, pancreatic body D10cc: r = 0.3209). The larger the stomach, the larger the radiation dose to the healthy portion of the pancreas outside the PTV.
When performing pancreatic SBRT, the dose to the OARs depends on the stomach size. Reducing the dose to the stomach and pancreas can be achieved by shrinking the stomach.
在临床实践中，进行胰腺立体定向体部放疗（SBRT）时，应仔细确定危及器官（OARs）。我们进行了一项模拟研究，以检查在进行胰腺 SBRT 时胃的大小对 OAR 辐射剂量的影响。
本研究纳入了 25 例患者。胰腺头和体肿瘤为 2cm 大小的假肿瘤，包含在大体肿瘤靶区（GTV）轮廓中。胃、胰腺、小肠、肝脏、肾脏和脊髓被视为 OARs。计划靶区（PTV）的处方剂量为 40Gy/5fx，并确定了 OARs 的剂量限制。记录了 OAR 体积的 X%在 X 值为 0.1、5.0 和 10.0cc 时的剂量（DX）以及 XGy 以上的 OAR 体积百分比。
就胰腺体肿瘤的辐射剂量而言，胃的大小与胃的 D10cc 剂量呈正相关（相关系数（r）=0.5516）。胰腺头肿瘤的辐射剂量与胃大小之间的 r 值为 0.3499。胃的大小与胰腺头和体的辐射剂量呈正相关（胰腺头 D10cc：r=0.3979，胰腺体 D10cc：r=0.3209）。胃越大，PTV 外胰腺健康部分的辐射剂量越大。
进行胰腺 SBRT 时，OARs 的剂量取决于胃的大小。通过缩小胃的大小，可以降低胃和胰腺的剂量。
