Evaluation of the mechanical isocenter and rotational angles of collimator, gantry, and patient couch in linear accelerator

Abstract

     Collimator, gantry and the couch are some of the important components used in radiotherapy. The mechanical stability of aforementioned components is one of the important factors affecting treatment outcome. This study focuses on evaluate the mechanical isocenter and rotational angles in linear accelerator. Measurements were compared to international recommendation from AAPM TG-198 and AAPM TG-142, which are 1^o and 1mm, respectively. Most of results is in accordance with recommendations except one. Medical physicists need to work with manufacturer’s engineer to identify the root causes. In terms of national regulations for linear accelerators, currently Viet Nam has only issued Circular 15/2017/BKHCN on declaration of standard conformity and technical-regulation conformity and methods for conformity assessment. Regulation on the quality assurance and external audit which is crucial for quality management has not been issued. Authors recommend that these documents should be drafted based on the reviewed scientific evidence.