适形调强放疗技术在局部晚期肺癌中的应用。

Normal lung sparing Tomotherapy technique in stage III lung cancer.

机构信息

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-Ro 81, Gangnam-Gu, Seoul, 06351, South Korea.

Department of Medical Device Management and Research, SAIHST, Sungkyunkwan University, Irwon-Ro 81, Gangnam-Gu, Seoul, 06351, South Korea.

出版信息

Radiat Oncol. 2017 Nov 6;12(1):167. doi: 10.1186/s13014-017-0905-x.

DOI:10.1186/s13014-017-0905-x

PMID:29110732

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5674800/

Abstract

PURPOSE

Radiation pneumonitis (RP) has been a challenging obstacle in treating stage III lung cancer patients. Beam angle optimization (BAO) technique for Tomotherapy was developed to reduce the normal lung dose for stage III non-small cell lung cancer (NSCLC). Comparative analyses on plan quality by 3 different Intensity-modulated radiation therapy (IMRT) methods with BAO were done.

MATERIALS AND METHODS

Ten consecutive stage IIIB NSCLC patients receiving linac-based static IMRT (L-IMRT) with total 66 Gy in 33 fractions to the PTV were selected. Two additional Tomotherapy-based IMRT plans (helical beam (TH-IMRT) and static beam (TD-IMRT)) were generated on each patient. To reduce the normal lung dose, Beam angles were optimized by using complete and directional block functions in Tomotherapy based on knowledge based statistical analysis. Plan quality was compared with target coverage, normal organ sparing capability, and normal tissue complication probability (NTCP). Actual beam delivery times and risk of RP related with planning target volume (PTV) were also evaluated.

RESULTS

The best PTV coverage measured by conformity index and homogeneity index was achievable by TH-IMRT (0.82 and 1.06), followed by TD-IMRT (0.81 and 1.07) and L-IMRT (0.75 and 1.08). Mean lung dose was the lowest in TH-IMRT plan followed by TD-IMRT and L-IMRT, all of which were ≤20 Gy. TH-IMRT plan could significantly lower the lung volumes receiving low to medium dose levels: V when compared to L-IMRT plan; and V when compared to TD-IMRT plan, respectively. TD-IMRT plan was significantly better than L-IMRT with respects to V and V and there was no significant difference with respect to V among three plans. The NTCP of the lung was the lowest in TH-IMRT plan, followed by TD-IMRT and L-IMRT (6.42% vs. 6.53% vs. 8.11%). Beam delivery time was the shortest in TD-IMRT plan followed by L-IMRT. As PTV length increased, NTCP and Mean lung dose proportionally increased significantly in all three plans.

CONCLUSION

Advantageous profiles by TH-IMRT could be achieved by BAO by complete and directional block functions. Current observation could help radiation oncologists to make wise selection of IMRT method for stage IIIB NSCLC.

摘要

目的

放射性肺炎（RP）一直是治疗 III 期肺癌患者的一个具有挑战性的障碍。Tomotherapy 的射束角度优化（BAO）技术是为了降低 III 期非小细胞肺癌（NSCLC）的正常肺剂量而开发的。对 3 种不同的调强放疗（IMRT）方法与 BAO 相结合的计划质量进行了比较分析。

材料与方法

选择了 10 例连续的 IIIB 期 NSCLC 患者，接受直线加速器静态调强放疗（L-IMRT），66 Gy 分 33 次照射至 PTV。对每位患者生成 2 个额外的 Tomotherapy 调强放疗计划（螺旋束（TH-IMRT）和静态束（TD-IMRT））。为了降低正常肺剂量，使用基于知识的统计分析，在 Tomotherapy 中使用完全和定向阻挡功能对射束角度进行优化。通过靶区覆盖、正常器官保护能力和正常组织并发症概率（NTCP）比较计划质量。还评估了与计划靶区（PTV）相关的实际射束输送时间和放射性肺炎（RP）的风险。

结果

TH-IMRT 计划可实现最佳的 PTV 覆盖率，测量值为适形指数和均匀性指数（0.82 和 1.06），其次是 TD-IMRT 计划（0.81 和 1.07）和 L-IMRT 计划（0.75 和 1.08）。TH-IMRT 计划的平均肺剂量最低，其次是 TD-IMRT 计划和 L-IMRT 计划，均≤20 Gy。TH-IMRT 计划可显著降低低至中剂量水平的肺容积：与 L-IMRT 计划相比，V ；与 TD-IMRT 计划相比，V 。TD-IMRT 计划在 V 和 V 方面明显优于 L-IMRT 计划，而在 3 种计划中，V 无显著差异。TH-IMRT 计划的肺 NTCP 最低，其次是 TD-IMRT 计划和 L-IMRT 计划（6.42%比 6.53%比 8.11%）。TD-IMRT 计划的射束输送时间最短，其次是 L-IMRT 计划。随着 PTV 长度的增加，在所有 3 种计划中，NTCP 和平均肺剂量均呈比例显著增加。