影像引导提高粒子植入治疗增益比的质量保证

Image guidance improves gain ratio in radioactive seeds brachytherapy

目的探讨通过实施多模态影像引导、放射剂量学优化等质量保证和质量控制措施能否保障和提高125I粒子植入治疗的靶向性。方法回顾性纳入2002年10月至2016年10月间经临床、支气管镜、影像学诊断及病理检查证实的非小细胞肺癌（NSCLC）患者287例（男184例，女103例，平均年龄61.9岁）和前列腺癌患者122例（平均年龄65.5岁）。采用符合线路SPECT/CT、CT、纤维支气管镜及超声显像进行靶区定位，应用治疗计划系统（TPS）制定方案并优化放射剂量学，以剂量－体积直方图（DVH）等评估TPS；影像引导粒子植入，并进行实时位置验证、植入后剂量学验证、疗效判定和随访。采用配对t检验分析数据。结果计划靶区（PTV）处方剂量（PD）均在140 Gy以上。对其中59例NSCLC和31例肺转移瘤患者分别进行即时剂量学验证，植入前后的放射分布一致性百分比分别为93.2%（55/59）和93.5%（29/31），90%大体肿瘤体积接受的剂量（D90）〉匹配周缘剂量（MPD）一致性百分比分别为93.2%（55/59）和87.1%（27/31），植入前后的MPD、D90和平均适形系数差异均无统计学意义（t值：2.11～9.71，均P〉0.05）；周围危及器官的平均照射剂量均明显低于正常组织耐受剂量，放射性肺炎发生率仅为1.05%（3/287），未发现其他严重不良反应。结论多模态影像靶向诊疗技术与优化能够提高125I粒子植入治疗的靶向性和治疗增益比。

ObjectiveTo investigate whether quality assurance and quality control using multimodal image guidance and radiation dosimetry optimization could ensure and improve the targeting of 125I seeds brachytherapy.MethodsA total of 287 patients （184 males, 103 females, average age 61.9 years） with non-small-cell lung cancer （NSCLC） and 122 patients （average age 65.5 years） with prostate cancer who were diagnosed by pathology or imaging methods（coincidence imaging, CT, flexible fiberoptic bronchoscopy, ultrasonography） from October 2002 to October 2016 were retrospectively enrolled. All imaging methods were used to locate the target area. Optimization of radiation dosimetry was made according to treatment planning system （TPS） and evaluated by dose-volume histogram （DVH）. 125I seeds implantation was performed under the imaging guidance, followed by real-time location verification, dosimetric verification. Therapeutic efficacy was evaluated. Paired t test was used to analyze the data.ResultsThe prescribed dose （PD） of planning target volume （PTV） was above 140 Gy. Immediate dosimetric verification was performed in 59 patients with NSCLC and 31 patients with pulmonary metastases. The radiation dose before and after the implantation was coincident in 93.2%（55/59） of NSCLC and 93.5%（29/31） of pulmonary metastases. The coincident rate of patients with dose delivered to 90% GTV （D90）〉matched peripheral dose （MPD） was 93.2%（55/59） and 87.1%（27/31） respectively in NSCLC and pulmonary metastases. There was no significant difference in MPD, D90 and conformity index （CI） before and after implantation （t values： 2.11-9.71, all P〉0.05）. The average dose of the risk organs was significantly lower than the tolerance dose of the normal tissue. The incidence of radiation pneumonitis was 1.05%（3/287）. No other serious complications were found.ConclusionTargeted diagnosis and therapy of multimodal image guidance could be optimized to improve the effect of targeting and therapeutic gain ratio of 125I seeds brachytherapy.