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Acceptance testing of linear accelerators: A multi-institutional analysis of adjustment limits
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T. Maeda   , Y. Kunii , Y. Saeki , T. Sasaki , S. Goto , T. Iseri , Y. Tanabe |
| Faculty of Medicine, Graduate School of Health Sciences, Okayama University, 2-5-1 Shikata, Kita, Okayama 700-8525, Japan , tanabey@okayama-u.ac.jp |
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Abstract: (11 Views) |
Background: Users of linear accelerators (linacs) often encounter challenges in understanding the adjustment limits and machine characteristics of the devices. This study analyzed the acceptance test data from linacs installed at multiple facilities to evaluate the adjustment limits for test criteria. Materials and Methods: Data were collected from eight TrueBeam, four VitalBeam, and one TrueBeam STx models (Varian Medical Systems, Palo Alto, CA, USA) installed between 2015 and 2024. The average values and standard deviations (SDs) for the radiation isocenter, multileaf collimator (MLC), JAW positional accuracy, beam quality, and beam profile (flatness and symmetry) were examined across facilities. Results: The SD of the radiation isocenter for the gantry and collimator was 0.01, which was smaller than that for the radiation isocenter, including the couch (0.06). The average MLC positional accuracy was less than half of the required tolerance, even though the SD was larger than that of the isocenter acceptance tests. The maximal JAW offset had an average value and SD exceeding >0.2 mm and 0.4 mm, respectively, with the Y JAW exhibiting greater variation than the X JAW. All photon beam quality measurements were within the tolerance of enhanced beam compatibility (≤±0.5). The SD for the flatness was smaller than that for the symmetry for both the in-line and cross-line measurements. Conclusion: Adjustments to the isocenter using software demonstrated minimal variations across facilities, whereas manual adjustments, including those for the MLC, JAW, beam quality, and profile, exhibited larger SDs. |
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| Keywords: Linear accelerator, acceptance test, multileaf collimator, radiation isocenter. |
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Full-Text [PDF 1174 kb]
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Type of Study: Original Research |
Subject:
Radiation Biology
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