Dosimetric Study of Radiotherapy for Liver Metastasis Cancer Based on 4D-CT Respiratory Gating Technology
HAN Jingjing1，GUO Yesong1，MOU Zhongde1，ZHAI Zhenyu1，JIANG Hongbing2,3，WU Yifan1，LIU Baoxi1，ZHANG Siyu1，YE Feng1
1. Department of Radiotherapy, Jiangsu Cancer Hospital, Nanjing Jiangsu 210006, China|2. Department of Medical Equipment,Nanjing First Hospital, Nanjing Medical University, Nanjing Jiangsu 210006, China|3. Nanjing Emergency Medical Center, Nanjing
Jiangsu 210003, China
Abstract：Objective To determine the motion characteristics of liver metastatic cancer based on 4D-CT and compare the geometric and dosimetric differences between 3D-CT, 4D-CT and gated CT plans. Methods Nine patients with liver metastases treated in our unit from September 2018 to December 2019 were selected. Each patient underwent a 3D-CT scan and a 4D-CT scan with a time dimension respectively, and the average images of time phase reconstruction at the end of respiration from 40% to 60% were selected
as gated CT|The tumor lesion GTV was delineated on each set of CT images, and PTV3D, PTV4D and PTVGate were obtained by adding different outer boundary and the treatment plan was designed for the target area of each CT. The prescription and distribution
of three different target area plans in the same patient were the same, and the volume and dosimetry of target area and OARS were compared among the three sets of plans. Results The study showed that the primary lesions of 9 patients with GTV movements in
the head and foot directions were significantly larger than the left and right and front and back directions, the average values were (0.75±0.37) cm, (0.16±0.08) cm and (0.45±0.244) cm. At the same time, the volume of the PTV3D tumor target area was the largest,
with an average value of (117.11±65.06) cm3, the average value of the PTV4D target volume was (84.92±52.14) cm3, and the volume of the PTVGate target area was the smallest, with an average value of (65.81±42.74) cm3. The doses D1, D99 and Dmean of the three
planned target area PTVs were not significantly different, and there was no clinical statistical difference. For the protection of normal organs, the average liver dose of Plan3D was (11.35±5.49) Gy, Plan4D was (10.22±5.73) Gy, and the minimum dose of PlanGate was
(9.144±5.462) Gy. In the protection of the right kidney, the average dose decreased from 6.36 Gy of Plan3D to 3.93 Gy of the gated plan (P=0.049). The high dose of the stomach decreased from 19.47 Gy to 15.42 Gy (P=0.048), so the gating plan’s protection of the
liver, right kidney and stomach was significantly better than the other two plans, but there was no statistical difference in the dose of the small intestine and spinal cord. Conclusion Our research confirms that gating technology can reduce the volume of PTV during radiotherapy for patients with liver metastases, thereby better protecting normal organs.
韩晶晶1，郭业松1，牟忠德1，翟振宇1，蒋红兵2,3，吴一凡1，刘宝喜1，张丝雨1，叶峰1. 基于4D-CT呼吸门控技术的肝转移癌放射治疗剂量学研究[J]. 中国医疗设备, 2020, 35(12): 24-28.
HAN Jingjing1，GUO Yesong1，MOU Zhongde1，ZHAI Zhenyu1，JIANG Hongbing2,3，WU Yifan1，LIU Baoxi1，ZHANG Siyu1，YE Feng1. Dosimetric Study of Radiotherapy for Liver Metastasis Cancer Based on 4D-CT Respiratory Gating Technology. China Medical Devices, 2020, 35(12): 24-28.
