Liu Xia, Tao Yinjie, Yang Bo, Pang Tingtian, Yu Lang, Li Wenbo, Feng Siqi, Liu Renqing, Li Jinsheng, Liu Zhikai, Qiu Jie
Department of Radiation Oncology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Our United Corporation, Xi'an, Shaanxi, China.
Med Phys. 2023 Mar;50(3):1855-1864. doi: 10.1002/mp.16142. Epub 2022 Dec 29.
Treatment of locally advanced pancreatic cancer (LAPC) has long been calling for advances in technology of radiotherapy. Patients who received radiotherapy still had high risks of local recurrence, while suffering from gastrointestinal side effects. Based on the inherent characteristics of the x-ray and γ-Ray radiation techniques, here we proposed and investigated an unexplored radiation therapy.
To investigate the potential clinical benefit of a novel x-ray and γ-Ray combination radiation technique in patients with LAPC.
Retrospective intensity-modulated radiotherapy (IMRT) treatment plans of 10 LAPC patients were randomly selected to compare with dual-modality plans. The prescribed dose to PGTV was 60.2 Gy. The PGTV dose was further escalated in dual-modality plan while maintaining clinically tolerable dose to organs at risk (OARs). Dosimetric comparisons were made and analyzed for three treatment plans (tomotherapy, standard dual-modality plan, escalated dual-modality plan) to assess the ability to increase dose to target volume while minimizing dose in adjacent OARs. Finally, radiobiological models were utilized for comparison.
All strategies resulted in dosimetrically acceptable plans. Dual-modality plans were present with similar conformity index (CI) and significantly lower gradient index (GI) compared with tomotherapy (3.64 ± 0.37 vs. 4.14 ± 0.61, p = 0.002; 3.64 ± 0.42 vs. 4.14 ± 0.61, p = 0.003). D of PGTV (65.46 ± 3.13 vs. 61.56 ± 1.00, p = 0.009; 77.98 ± 5.86 vs. 61.56 ± 1.00, p < 0.001) and PCTV (55.04 ± 2.14 vs. 53.93 ± 1.67, p = 0.016; 58.24 ± 3.24 vs. 53.93 ± 1.67, p = 0.001) were significantly higher, while D of the stomach was reduced in both dual-modality plans (17.98 ± 10.23 vs. 19.34 ± 9.75, p = 0.024; 17.62 ± 9.92 vs. 19.34 ± 9.75, p = 0.040). The lower V in the liver (4.83 ± 5.87 vs. 6.23 ± 6.68, p = 0.015; 4.90 ± 5.93 vs. 6.23 ± 6.68, p = 0.016) and lower V of the small intestine (3.35 ± 3.30 vs. 4.06 ± 3.87, p = 0.052) were found in dual-modality plans. Meanwhile, radiobiological models demonstrated higher probability of tumor control (29.27% ± 9.61% vs. 18.34% ± 4.70%, p < 0.001; 44.67% ± 18.16% vs. 18.34% ± 4.70%, p = 0.001) and lower probability of small intestine complication (2.16% ± 2.30% vs. 1.25% ± 2.72%, p = 0.048) in favor of dual-modality strategy.
A novel dual-modality strategy of x-ray and γ-Ray combination radiation appears reliable for target dose escalation and normal tissue dose reduction. This strategy might be beneficial for local tumor control and the protection of normal organs in patients with LAPC.
局部晚期胰腺癌（LAPC）的治疗长期以来一直需要放疗技术的进步。接受放疗的患者仍有较高的局部复发风险，同时还会遭受胃肠道副作用。基于X射线和γ射线辐射技术的固有特性，我们在此提出并研究一种未被探索的放射治疗方法。
探讨一种新型X射线和γ射线联合辐射技术对LAPC患者的潜在临床益处。
随机选择10例LAPC患者的回顾性调强放疗（IMRT）治疗计划，与双模态计划进行比较。计划靶体积（PGTV）的处方剂量为60.2 Gy。在双模态计划中进一步提高PGTV剂量，同时保持危及器官（OARs）的临床可耐受剂量。对三种治疗计划（断层放疗、标准双模态计划、递增双模态计划）进行剂量学比较和分析，以评估增加靶区体积剂量同时最小化相邻OARs剂量的能力。最后，利用放射生物学模型进行比较。
所有策略均产生了剂量学上可接受的计划。与断层放疗相比，双模态计划的适形指数（CI）相似，梯度指数（GI）显著更低（3.64±0.37对4.14±0.61，p = 0.002；3.64±0.42对4.14±0.61，p = 0.003）。PGTV的剂量（65.46±3.13对61.56±1.00，p = 0.009；77.98±5.86对61.56±1.00，p < 〇.〇〇1）和计划靶体积外扩体积（PTV）的剂量（55.04±2.14对53.93±1.67，p = 0.016；58.24±3.24对53.93±1.67，p = 0.001）显著更高，而在两种双模态计划中胃的剂量均降低（17.98±10.23对19.34±9.75，p = 0.024；17.62±9.92对19.34±9.75，p = 0.040）。在双模态计划中，肝脏的较低体积（4.83±5.87对6.23±6.68，p = 0.015；4.90±5.93对6.23±6.68，p = 0.016）和小肠的较低体积（3.35±...
