New Method of Quality Control Test for Light and Radiation Field Coincidence in Medical Linear Accelerators

Heravian Shandiz, Mahdi and Safaeian Layen, Ghorban and Bahreyni-Toosi, Mohammad-Hossein and Feyzi, Ali and Ziaei, Amir Hossein (2019) New Method of Quality Control Test for Light and Radiation Field Coincidence in Medical Linear Accelerators. Iranian Journal of Medical Physics, 16 (5). pp. 336-340.

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Introduction: The evaluation of X-ray and light field coincidence in linear accelerators as a quality control test is often performed subjectively, involving the manual marking of films and their visual inspection following the irradiation. Therefore, the present study aimed to develop an objective method for the performance of this test leading to the increased levels of accuracy, precision, and speed for the measurement of X-ray and light field coincidence. Material and Methods: The new method involved a portable, lightweight, and inexpensive device containing optically-shielded and non-shielded photodiodes to detect the location and dimensions of the light and X-ray fields. The obtained results were analyzed using purpose-written user-friendly software. Results: On the basis of the results, this system could be a reliable method to measure the coincidence of the two fields with the accuracy of 0.5 mm and average field size standard deviations of Elekta Presice and Siemens Primus are 22.47 mm2 and 22.36 mm2, respectively. The result was well within the tolerance recommended by the American Association of Physicists in Medicine task group report number 142. Conclusion: The proposed method allows accurate and precise measurements through a largely automated process. Therefore, the measurement results benefit from the reduced level of subjectivity or human error, compared to the standard film-based technique.Â

Item Type: Article
Uncontrolled Keywords: Quality Control,Quality Assurance,Radiation
Subjects: WN Radiology . Diagnostic Imaging
Divisions: Journals > Iranian J Medical Physics
Depositing User: ijmp ijmp
Date Deposited: 02 Sep 2019 04:35
Last Modified: 02 Sep 2019 04:35

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