Assessing Tomotherapy Performance Post-Linac Replacement: A Dosimetric Comparison with Manufacturer's Gold Data

Abstract

This study aimed to experimentally compare dosimetric measurement data obtained after linac replacement in a Tomotherapy HiArt system with the "gold data" provided by the manufacturer, according to the acceptance criteria recommended by AAPM TG-148. Energy quality (TPR1.5/10), percentage depth dose (PDD), transverse and longitudinal beam profiles, and patient treatment plan quality assurance (QA) measurements were performed and compared with gold data. The difference between the gold and measured data in the energy quality measurement was 0.5%. In the PDD measurements, the difference in dmax values remained at a maximum of 0.9 mm, and the PDD20/10 ratio remained below 1%. Agreement within the 1% tolerance limits was also observed in the transverse and longitudinal profiles. Furthermore, the patient QA measurements were in agreement with the results obtained using the previous linac. The findings demonstrated that all measurements remained within the TG-148 criteria, indicating that linac replacement did not significantly affect system performance. These results confirmed that the TomoTherapy HiArt system provides reliable and accurate dosimetric measurements following linac replacement, ensuring consistent and high-quality patient treatment delivery.

Keywords

• Tomotherapy
• AAPM TG-148
• Dosimetric measurement
• Gold standart data
• Linac replace

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