Exploring the dosimetric advantages of a novel multi-modality radiotherapy platform in prostate cancer

The present research aims to explore the dosimetric advantages associated with a novel multi-modality radiotherapy platform TaiChiB, which integrates a medical linac and a focused ⁶⁰Co γ-ray system. The primary focus of this investigation is to assess the efficacy of this platform in the treatment of prostate cancer. A retrospective study was conducted involving fifteen prostate patients. Each patient had two different treatment plans: a Varian linac x-ray plan (group A), and a TaiChiB plan combined with linac x rays and focused γ rays (group B). In both plan groups, the prescribed dose to the planning target volume (PTV) was 50 Gy, with a boost dose of 20 Gy to the gross tumor volume (GTV). In the TaiChiB plan, the primary plan was delivered using linac x rays and the boost dose plan was delivered using γ rays. Different criteria were used to evaluate the plan quality and results from the two plan groups were compared through statistical analysis (p < 0.05 as significantly different). All plans from these two groups met the clinical requirements for treatment, and Gamma passing rates were above 95% using the 3%/2 mm criterion suggested by TG-218. Regarding the dose coverage to targets, the TaiChiB plan group had a higher mean dose to the GTV (77.46 ± 1.04 Gy (B) vs. 71.40 ± 0.33 Gy (A), p < 0.01), whereas it maintained a comparable mean dose to the PTV (55.33 ± 1.76 Gy (B) vs. 55.23 ± 1.92 Gy (A), non-significant). In terms of dose to organs-at-risk (OARs), the TaiChiB plan group showed a lower or comparable mean value. In detail, bladder V_45Gy (43.90 ± 6.34% (B) vs. 49.83 ± 6.31% (A), p < 0.01); rectum V_45Gy (38.45 ± 14.38% (B) vs. 51.46 ± 17.18%(A), p < 0.01); intestine V_45Gy (163.88 ± 18.85 cm³ (B) vs. 177.18 ± 18.20 cm³ (A), p < 0.01); left femoral head V_30Gy (5.63 ± 1.97% (B) vs. 11.83 ± 2.56% (A), p < 0.01); and right femoral head V_30Gy (4.64 ± 1.94% (B) vs. 10.38 ± 2.73% (A), p < 0.01). The comparison of plan evaluation results showed the superiority of the novel multi-modality radiotherapy platform TaiChiB in dosimetric characteristics by harnessing the physical advantages of γ rays as a supplement to x rays in radiotherapy.