방사선의학 웹진

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본 시스템은 두 대의 스마트폰 (device, displayer)으로 구성되어 있다. 선형가속기 겐트리에 부착된 device의 모션센서를 이용해 겐트리와 콜리메이터의 회전각도를 측정하고, 고해상도의 후면 카메라를 이용하여 조사야의 크기 등을 측정한다. displayer는 device와 Bluetooth로 연결되어 device로 측정한 data를 전송받게 된다.​

Abstract

Mechanical quality assurance (QA) of medical linear accelerators consists of time-consuming and human-error-prone procedures. We developed a smartphone application system for mechanical QA. The system consists of two smartphones: one attached to a gantry for obtaining real-time information on the mechanical parameters of the medical linear accelerator, and another displaying real-time information via a Bluetooth connection with the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations. Images taken by the smartphone's high-resolution camera were processed to evaluate accuracies of jaw-positioning, crosshair centering and source-to-surface distance (SSD). The application was developed using Android software development kit and OpenCV library. The accuracy and precision of the system was validated against an optical rotation stage and digital calipers, prior to routine QA measurements of five medical linear accelerators. The system accuracy and precision in measuring angles and lengths were determined to be 0.05  ±  0.05° and 0.25  ±  0.14 mm, respectively. The mean absolute errors (MAEs) in QA measurements of gantry and collimator rotation were 0.05  ±  0.04° and 0.05  ±  0.04°, respectively. The MAE in QA measurements of light field was 0.39  ±  0.36 mm. The MAEs in QA measurements of crosshair centering and SSD were 0.40  ±  0.35 mm and 0.41  ±  0.32 mm, respectively. In conclusion, most routine mechanical QA procedures could be performed using the smartphone application system with improved precision and within a shorter time-frame, while eliminating potential human errors. 

Author information

Kim H1, Lee H, Park JI, Choi CH, Park SY, Kim HJ, Kim YS, Ye SJ.​

1 Interdisciplinary program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul, Republic of Korea. Department of Radiation Oncology, Jeju National University Hospital, Jeju, Republic of Korea.