Report of four cases of pulmonary malignant tumors treated with SBRT using BODYFIX plus 4D-CBCT image guidance technique.

Abstract

e20050 Background: To monitor the range of motion in SBRT treatment of lung tumors by using BODYFIX combined with four-dimensional cone beam CT (4D-CBCT), and provide evidence for delineating the reasonable internal target area (ITV) of lung cancer, and observe the short-term outcom of treatment and treatment of complications. Methods: 4D-CT was used to locate CT scan, delineate the GTV of the tumor, make a simple radiation treatment planning, determine the treatment center point, and then use line accelerator 4D-CBCT to perform pre-SBRT treatment on 4 patients with lung malignant tumor. The system automatically reconstructs the image and matches the CT image of the treatment plan to obtain the placement error of the patient in the head and foot (SI), left and right (LR), and front and rear (AP) directions. The double registration technique is used to correct the correction first. Positioning error, the 4D-CBCT dynamic image is again registered with the target area, the range of motion within the tumor is observed, and the time-weighted 4D-CBCT image is transmitted back to the Monaco planning system to delineate the target area to accurately determine the range of the ITV. According to this target area, a radiation treatment planning was developed, GTV 20Gy/f, 1 to 3 fractions, and then 4D-CBCT scan was performed in each SBRT treatment to observe the range of tumor motion in real time. Results: 3 of the 4 patients the lung tumors were CR at 3 months after treatment, and 1 patient was SD. No serious complications occurred during the treatment or within 3 months after radiotherapy. Conclusions: The BODYFIX plus 4D-CBCT image can more accurately outline the ITV range of lung cancer. The patient is well tolerated and the short-term outcom is good.