Abstract：
BACKGROUND: 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.
OBJECTIVE: To investigate the potential clinical benefit of a novel x-ray and γ-Ray combination radiation technique in patients with LAPC.
METHODS: 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.
RESULTS: 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). Dmean 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 Dmean 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 V30Gy 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 V45Gy 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.
CONCLUSIONS: 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.
OBJECTIVE: To investigate the potential clinical benefit of a novel x-ray and γ-Ray combination radiation technique in patients with LAPC.
METHODS: 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.
RESULTS: 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). Dmean 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 Dmean 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 V30Gy 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 V45Gy 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.
CONCLUSIONS: 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.
摘要：
背景：局部晚期胰腺癌（LAPC）的治疗长期以来一直呼吁放射治疗技术的进步。接受放疗的患者局部复发的风险仍然很高，而患有胃肠道副作用。根据X射线和γ射线辐射技术的固有特性，在这里，我们提出并调查了一种未经探索的放射治疗。
目的：研究一种新型X线和γ线联合放射技术在LAPC患者中的潜在临床益处。
方法：随机选择10例LAPC患者的回顾性调强放疗（IMRT）治疗方案，与双模式方案进行比较。PGTV的处方剂量为60.2Gy。PGTV剂量在双模态计划中进一步升级,同时维持对处于危险中的器官(OAR)的临床可耐受剂量。进行了剂量学比较，并分析了三种治疗计划（断层疗法，标准双模态计划，逐步升级的双模态计划），以评估在相邻OAR中增加剂量至目标体积的同时最小化剂量的能力。最后,使用放射生物学模型进行比较。
结果：所有策略均产生剂量可接受的计划。与断层治疗相比，双模态计划具有相似的整合指数（CI）和显着较低的梯度指数（GI）（3.64±0.37vs.4.14±0.61，p=0.002；3.64±0.42vs.4.14±0.61，p=0.003）。PGTV的平均值（65.46±3.13vs.61.56±1.00，p=0.009；77.98±5.86vs.61.56±1.00，p<0.001）和PCTV（55.04±2.14vs.53.93±1.67，p=0.016；58.24±3.24vs.53.93±1.67，p=0.001）明显更高，而在两种双模式计划中，胃的平均指数均降低（17.98±10.23vs.19.34±9.75，p=0.024；17.62±9.92vs.19.34±9.75，p=0.040）。肝脏中V30Gy较低（4.83±5.87vs.6.23±6.68，p=0.015；4.90±5.93vs.6.23±6.68，p=0.016）和较低的小肠V45Gy（3.35±3.30vs.在双模态计划中发现4.06±3.87，p=0.052）。同时,放射生物学模型显示出更高的肿瘤控制概率（29.27％±9.61％vs.18.34%±4.70%,p<0.001;44.67%±18.16%vs.18.34%±4.70%,p=0.001），小肠并发症的概率较低（2.16%±2.30%vs.1.25%±2.72%,p=0.048)支持双模态策略。
结论：一种新的X射线和γ射线联合辐射的双模态策略对于靶剂量递增和正常组织剂量减少似乎是可靠的。该策略可能有益于LAPC患者的局部肿瘤控制和正常器官的保护。
目的：研究一种新型X线和γ线联合放射技术在LAPC患者中的潜在临床益处。
方法：随机选择10例LAPC患者的回顾性调强放疗（IMRT）治疗方案，与双模式方案进行比较。PGTV的处方剂量为60.2Gy。PGTV剂量在双模态计划中进一步升级,同时维持对处于危险中的器官(OAR)的临床可耐受剂量。进行了剂量学比较，并分析了三种治疗计划（断层疗法，标准双模态计划，逐步升级的双模态计划），以评估在相邻OAR中增加剂量至目标体积的同时最小化剂量的能力。最后,使用放射生物学模型进行比较。
结果：所有策略均产生剂量可接受的计划。与断层治疗相比，双模态计划具有相似的整合指数（CI）和显着较低的梯度指数（GI）（3.64±0.37vs.4.14±0.61，p=0.002；3.64±0.42vs.4.14±0.61，p=0.003）。PGTV的平均值（65.46±3.13vs.61.56±1.00，p=0.009；77.98±5.86vs.61.56±1.00，p<0.001）和PCTV（55.04±2.14vs.53.93±1.67，p=0.016；58.24±3.24vs.53.93±1.67，p=0.001）明显更高，而在两种双模式计划中，胃的平均指数均降低（17.98±10.23vs.19.34±9.75，p=0.024；17.62±9.92vs.19.34±9.75，p=0.040）。肝脏中V30Gy较低（4.83±5.87vs.6.23±6.68，p=0.015；4.90±5.93vs.6.23±6.68，p=0.016）和较低的小肠V45Gy（3.35±3.30vs.在双模态计划中发现4.06±3.87，p=0.052）。同时,放射生物学模型显示出更高的肿瘤控制概率（29.27％±9.61％vs.18.34%±4.70%,p<0.001;44.67%±18.16%vs.18.34%±4.70%,p=0.001），小肠并发症的概率较低（2.16%±2.30%vs.1.25%±2.72%,p=0.048)支持双模态策略。
结论：一种新的X射线和γ射线联合辐射的双模态策略对于靶剂量递增和正常组织剂量减少似乎是可靠的。该策略可能有益于LAPC患者的局部肿瘤控制和正常器官的保护。
