Open AccessDevices for dosimetric measurements and quality assurance of the Xstrahl 300 orthovoltage unit
Author(s) -
Lim Tze Yee,
Mirkovic Dragan,
Wang Xin,
Tailor Ramesh
Publication year - 2021
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.13220
Subject(s) - monitor unit , quality assurance , dosimeter , medical physics , reproducibility , ionization chamber , linear particle accelerator , dosimetry , dose profile , computer science , nuclear medicine , beam (structure) , optics , physics , medicine , mathematics , ion , statistics , external quality assessment , pathology , quantum mechanics , ionization
The Xstrahl 300 orthovoltage unit is designed to deliver kilovoltage radiation therapy using the appositional technique. However, it is not equipped with some typical linear accelerator features, such as mechanical distance indicator and crosshair projection, which are useful for facilitating equipment setup during various quality assurance (QA) and research activities. Therefore, we designed and constructed slip‐in devices to facilitate QA for dosimetric measurements of our Xstrahl 300 unit. These include: (a) an ion chamber positioning system for dosimetric measurements, (b) a mechanical pointer for setting dosimeter distance to a nominal 50 cm, and (c) a crosshair projector with built‐in light to facilitate alignment of dosimeter to the center of the radiation field. These devices provide a high degree of setup reproducibility thereby minimizing setup errors. We used these devices to perform QA of the Xstrahl 300 orthovoltage unit. One of the QA tests we perform is a constancy check of beam output and energy. Our data since start of clinical use of this unit (approximately 2.5 yr) show dose outputs to be remarkably reproducible (2σ = ±0.4%) for all three clinical beams (75, 125, and 250 kVp). These devices have provided both convenience and high‐precision during the unit’s commissioning, and continue to provide the same for various QA activities on the Xstrahl 300 orthovoltage unit.