Development and verification of LEP 300 kilovoltage radiotherapy system for companion animals

Abstract

The Life Extension for Pets (LEP) 300 is a radiotherapy system developed by the AURA CARE Company for companion animals. For the performance evaluation of LEP 300 kilovoltage treatment equipment, which is the purpose of this study, we conducted acceptance tests and beam commissioning using water-equivalent solid phantom, Gafchromic EBT3 film, and an ion chamber. We investigated the mechanical functionality, such as gantry angle accuracy, couch accuracy, half-value layer (HVL), field size accuracy, and alignment. We measured the absolute dose, percent depth dose (PDD), beam profile for the full width at half maximum (FWHM), flatness, asymmetry, penumbra, and output factor to evaluate the beam characteristic. The main measurement value was input to the Radiation Treatment Planning (RTP) software and used for calculations and compared with other independent data measured. Most of the measured values for mechanical checks were within the tolerances of the medical linear accelerator (LINAC). The output of the beam was 1.295 Gy/min at a depth of 2 cm, and the difference between the PDD data and the RTP system was within 2.134%. The penumbra difference between the measured profile data and RTP was within 1.02 cm in the 10 × 10 cm2 field. We confirmed the mechanical accuracy and dosimetry characteristics of the LEP 300 kV radiotherapy equipment. However, the global errors of the profile outside of the penumbra were significantly higher, at a maximum of 11.6%. They were caused by the low dose effects under 300 kV energy. In the future, it is thought that it will be possible to increase the accuracy of the RTP system through the improvement of the dose calculation algorithm. We think our study results will help establish a quality verification standard for the kV energy area and a systematic protocol for the periodic management of equipment.