Document Type: Conference Proceedings
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA. School of Physical Sciences, the University of Adelaide, SA 5005 AUSTRALIA.
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA 5000 AUSTRALIA.
Introduction: Very low, Low and Medium X-ray machines are used extensively for Superficial Radiation Therapy mostly used for Basal Cell, Squamous Cell Carcinoma, and Melanoma skin cancers. In most of cases, Superficial X-ray Therapy (SXRT) is preferred to Electron beams generated using a linear accelerator. SXRT tube characteristics may vary with the use of the machine for a long time. This study investigates the variation of machine output characteristics acquired during machine commissioning and applied for treatment planning system.
Materials and Methods: A Gulmay D3150 Superficial Unit was used for all data collected. At the first stage, beam quality index, half Value Layer (HVL), radiation beam profiles in different depths for a range of applicator for all available applicators were collected. At the end, machine output was also compared with baseline established during the machine commissioning.
Results: Result shows that there is a systemic variation of the beam quality index up to 4.3%. Although results are found to be within tolerance, but a systemic variation of the data acquired shows that machine characteristics are modified.
Conclusion: As a systemic change of machine output is observed, based on data achieved, more detailed QA checks, annual QA program and re-commissioning of the machine for more accurate treatment is recommended.