Affiliations: [a]
Department of Radiotherapy Center, Jinling Hospital, Nanjing, China
| [b]
School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| [c]
Department of Emergency, Shenzhen Hospital of Southern Medical University, Shenzhen, Guangdong Province, China
Correspondence:
[*]
Corresponding author: Yongjian Wang, Department of Emergency, Shenzhen Hospital of Southern Medical University, No. 1333, Xinhu Road, Bao’an District, Shenzhen, Guangdong 518036, China. Tel.: +86 15151870800; Fax: +86731360; E-mail: wyjyub@163.com.
Abstract: Tumor tracking is performed during patient set-up and monitoring of respiratory motion in radiotherapy. In the clinical setting, there are several types of equipment for this set-up such as the Electronic Portal imaging Device (EPID) and Cone Beam CT (CBCT). Technically, an optical positioning system tracks the difference between the infra ball reflected from body and machine isocenter. Our objective is to compare the clinical positioning error of patient setup between Cone Beam CT (CBCT) with the Optical Positioning System (OPS), and to evaluate the traditional positioning systems and OPS based on our proposed approach of patient positioning. In our experiments, a phantom was used, and we measured its setup errors in three directions. Specifically, the deviations in the left-to-right (LR), anterior-to-posterior (AP) and inferior-to-superior (IS) directions were measured by vernier caliper on a graph paper using the Varian Linear accelerator. Then, we verified the accuracy of OPS based on this experimental study. In order to verify the accuracy of phantom experiment, 40 patients were selected in our radiotherapy experiment. To illustrate the precise of optical positioning system, we designed clinical trials using EPID. From our radiotherapy procedure, we can conclude that OPS has higher precise than conventional positioning methods, and is a comparatively fast and efficient positioning method with respect to the CBCT guidance system.
