[Evaluation of the Position Matching Accuracy for Radiological Technologists and Radiation Oncologists in Image-guided Radiation Therapy].

Purpose: The promotion of task-shifting and task-sharing to facilitate work style reform for physicians has enabled radiological technologists (RTs) to perform primary matching in image-guided radiotherapy. The purpose in this study is to evaluate the position matching accuracy of RTs and radiation oncologist (ROs).

Methods: Position matching was performed by four RTs and two ROs (RO-A and B). To evaluate the accuracy of the observer's position matching, five cases each were identified for the head, neck, chest, and pelvic regions in two-dimension planar images (2D/2D), and for the prostate in three-dimensional (3D) images (CBCT). Manual position matching was performed using the offline matching of the position matching analysis software at a position moved by 3-7 mm in the XYZ directions from the treatment position at the time of treatment. Inter-observer position matching accuracy was evaluated by calculating the difference between the treatment position and the matching position, and by calculating a 3D vector from the above difference.

Results: The differences between the irradiation position and the reference position were within ±1.0 mm for 2D/2D and within ±1.5 mm for CBCT for the four RTs, while the maximum differences for RO-A were 3.0 mm and 3.5 mm, respectively. For 3D vectors, in 2D/2D, the values for four RTs and RO-B were 0.1-0.6 mm, compared to RO-A was 1.2-1.7 mm, and in CBCT, the values for four RTs were 0.3-0.7 mm, compared to the two ROs' were 1.3 mm and 1.4 mm.

Conclusion: The position matching accuracy of our RTs was not inferior to that of ROs, confirming that primary matching by RTs is clinically acceptable.