Treatment plan quality on a new slip ring-mounted radiotherapy system for cervical and breast cancer: Dosimetry and plan complexity analysis

Purpose: This study focuses on evaluating the performance of ring-mounted LINAC TAICHI, a novel radiotherapy system, with treatment plans obtained from Raystation TPS (TAICHI-RS), by comparing its plans with those on the C-arm LINAC TrueBeam with Eclipse TPS (TrueBeam-E) in the context of cervical cancer and breast cancer treatments. The study aims to assess the dosimetric results and plan complexity metrics of this new system. Method and materials: The research randomly selected 13 cervical cancer and 11 breast cancer patients treated with VMAT on the TAICHI LINAC. The plans were reproduced in Eclipse TPS for the TrueBeam LINAC using the same CT and structure sets. Dosimetric metrics, including dose distribution in the target volume and the dose received by OARs, were analyzed. Complexity metrics were also assessed to evaluate plan complexity. In addition, patient-specific quality assurance (PSQA) was measured for both TAICHI-RS and TrueBeam-E systems. Results: Results have shown that in cervical cancer plans, both systems performed similarly in terms of OARs. In breast cancer plans, TAICHI-RS system demonstrated significant advantages, achieving better dose homogeneity, lower irradiated doses in OARs, and more uniform dose distributions in the target volume compared to TrueBeam-E system (P values < 0.05). Complexity metrics indicated that for cervival cancer, TAICHI-RS plans were generally more complex than TrueBeam-E plans, while they were similar for breast cancer. The average PSQA passing rates of TAICHI-RS versus TrueBeam-E systems were 98.5% versus 98.7% (2%/2 mm criteria) and 99.9% versus 99.9% (3%/3 mm criteria) for cervival cancer plans, and 95.7% versus 97.4% (2%/2 mm criteria) and 99.3% versus 99.5% (3%/3 mm criteria) for breast cancer plans respectively. Conclusion: In conclusion, the new TAICHI-RS system was demonstrated to be clinically useful and accurate in delivering treatment plans for cervical and breast cancer. The study suggests that TAICHI-RS system could offer advantages in breast cancer treatments particularly. Further multi-center research is recommended for comprehensive validation.