Introduction: The impact of dose heterogeneity within the tumor on TCP and NTCP was studied using various radiobiological models. The effect of the degree of heterogeneity index (HI) on TCP was also analyzed. Materials and Methods: Thirty-seven pre-treated liver SBRT cases were included in this study. Two different kinds of treatment techniques were employed. In both arms, the prescribed dose was received by 95% of the PTV. Initially, the inhomogeneous treatment plans (IHTP) were made in which the spatial change of dose within the PTV was high and the maximum dose within the PTV can go up to 160%. Subsequently, in another arm, homogeneous treatment plans (HTP) were generated in which PTV was covered with the same prescription isodose and the maximum dose can go up to 120%. As per RTOG 1112, all organs at risk (OAR’s) were considered while optimization of the treatment plans. TCP was calculated using the Niemierko and Poisson model. NTCP was calculated using the Niemierko and LKB fractionated model. Results: For the IHTP, TCP was decreasing as ‘a’ value decreased in the Niemierko model whereas, for HTP, TCP was found to be the same. NTCP of the normal liver was less in IHTP as compared to HTP, and the Niemierko model overestimates the NTCP as compared to LKB fractionated model. NTCP for all other OAR’s was <1% in both kinds of treatment plans. Conclusion: IHTP is found to be clinically better than HTP because NTCP of the normal liver was significantly less and TCP was more for certain ‘a’ values of the Niemierko model and the Poisson model. There is not any effect of HI on TCP was observed. Advances in knowledge: IHTP could be used clinically because of the dose-escalation and subsequently, leads to an increase in the TCP.

简介：使用各种放射生物学模型研究了肿瘤内剂量异质性对 TCP 和 NTCP 的影响。还分析了异质性指数（HI）对TCP的影响。材料和方法：本研究包括 37 例预先治疗的肝脏 SBRT 病例。采用了两种不同的处理技术。在两组中，95% 的 PTV 均接受了规定剂量。最初，制定了不均匀治疗计划（IHTP），其中 PTV 内的剂量空间变化很大，PTV 内的最大剂量可高达 160%。随后，在另一组中，生成了均质治疗计划 (HTP)，其中 PTV 覆盖了相同的处方等剂量，最大剂量可高达 120%。根据 RTOG 1112，在优化治疗计划时考虑了所有处于危险中的器官 (OAR)。TCP 使用 Niemierko 和 Poisson 模型计算。NTCP 是使用 Niemierko 和 LKB 分级模型计算的。结果：对于 IHTP，TCP 随着 Niemierko 模型中“a”值的降低而降低，而对于 HTP，TCP 被发现是相同的。与 HTP 相比，IHTP 中正常肝脏的 NTCP 较少，与 LKB 分级模型相比，Niemierko 模型高估了 NTCP。在两种治疗计划中，所有其他 OAR 的 NTCP 均 <1%。结论：发现 IHTP 在临床上优于 HTP，因为对于 Niemierko 模型和 Poisson 模型的某些“a”值，正常肝脏的 NTCP 显着减少，而 TCP 更多。没有观察到 HI 对 TCP 的任何影响。知识进步：由于剂量递增，IHTP 可用于临床，随后导致 TCP 增加。