Dosimetric advantages of a novel X-Ray/γ-Ray integrated radiotherapy platform in cervical carcinoma: A comparative...

This study evaluates the dosimetric benefits of TaiChi, a novel radiotherapy platform combining 6MV linac-based volumetric-modulated arc therapy (VMAT) and γ-ray stereotactic radiotherapy, for locally advanced cervical carcinoma (LACC) with pelvic lymph node metastases.

Twelve LACC cases were retrospectively analyzed, comparing TaiChi plans with conventional treatment plans. The prescribed doses were standardized at 50 Gy for the planning target volume (PTV) and 12.5 Gy for the PTVLn-a boost volume delivering focal dose escalation to metastatic lymph nodes.Conventional treatment plans were developed using the Varian Eclipse 13.5 treatment planning system (TPS) with VMAT techniques. In contrast, TaiChi plans were generated using the RTPRO TPS (OUR United Corp., China), leveraging the platform's unique dual-modality capabilities: a 6MV linac-based VMAT plan was optimized for PTV coverage, while gamma knife was utilized for PTVLn dose escalation. A comprehensive dosimetric comparison was conducted to evaluate the system's ability to simultaneously achieve PTVLn dose escalation and organs-at-risk (OARs) sparing.

TaiChi achieved comparable PTVLn conformity (CI: 0.86 ± 0.06 vs. 0.87 ± 0.02, p = 0.299) but superior dose gradient (GI: 2.03 ± 0.27 vs. 2.21 ± 0.32, p < 0.001). Significant PTVLn dose escalation was observed with TaiChi: mean dose (68.58 ± 0.52 Gy vs. 63.55 ± 1.01 Gy, p < 0.001), D₉₈ (61.81 ± 0.55 Gy vs. 57.09 ± 1.70 Gy, p < 0.001), and D₂ (75.02 ± 1.61 Gy vs. 65.36 ± 2.74 Gy, p < 0.001). PTV D2 was moderately higher with TaiChi (64.11 ± 4.01 Gy vs. 62.17 ± 2.68 Gy, p = 0.04). OAR sparing improved significantly: bladder, rectum, and small intestine V45Gy decreased by 3.7 %, 5.1 %, and 3.9 %, respectively.

TaiChi's synergistic X-ray/γ-ray approach enables safe dose escalation to metastatic nodes while reducing OAR exposure, potentially enhancing tumor control and toxicity outcomes for node-positive cervical carcinoma.