Smartphone application for mechanical quality assurance of medical linear accelerators

Hwiyoung Kim, Hyunseok Lee, Jong In Park, Chang Heon Choi, So Yeon Park, Hee Jung Kim, Young Suk Kim, Sung Joon Ye

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)N257-N270
JournalPhysics in medicine and biology
Issue number11
StatePublished - May 10 2017
Externally publishedYes


  • mechanical QA
  • medical linear accelerator
  • precision
  • smartphone

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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