4D-CT联合呼吸门控技术应用于肺癌立体定向体部放疗的临床研究

Clinical study on 4D-CT combined with respiratory gating technology in stereotactic body radiotherapy for lung cancer

目的本研究将4D-CT联合呼吸门控技术应用于转移性或原发性肺癌的立体定向体部放疗(SBRT),探讨其靶区大小、剂量学差异、放疗不良反应及临床疗效。方法收集扬州大学附属医院放疗中心治疗的32例转移性或原发性肺癌患者(共54个病灶)的数据,将患者CT数据通过4D软件程序进行处理,共得到10组CT图像,制订呼吸门控计划和常规放疗计划,比较2种计划勾画的靶区体积及剂量,并在治疗结束3个月内随访观察患者放疗不良反应及疗效。结果与常规计划比较,呼吸门控计划下的内靶区(ITV)、计划靶区(PTV)体积更小,95%PTV接受的剂量(D)更高,差异有统计学意义(P<0.05)。呼吸门控计划下的正常肺组织接受放射剂量高于20 Gy照射的体积百分比(V)、正常肺组织接受放射剂量高于5 Gy照射的体积百分比(V)、双肺接受的平均剂量(MLD)和脊髓1 cm~3体积接受的剂量(D)较常规计划更小,差异有统计学意义(P<0.05)。随访结果表明,1~2级放射性肺炎发生率为25.0%,治疗总有效率为65.6%。结论4D-CT联合呼吸门控技术可应用于肺癌的SBRT,尤其适用于多发肺转移瘤患者,能精确追踪多个肿瘤位置,在保证治疗有效性和准确性的同时减少周围正常组织不良反应的发生。

Objective To explore target size, dosimetric difference, adverse reactions and clinical efficacy of radiotherapy by 4D-CT combined with respiratory gating technique in stereotactic body radiotherapy(SBRT) for metastatic or primary lung cancer. Methods The data of 32 patients(54 lesions) with metastatic or primary lung cancer treated in the Radiotherapy Center of Affiliated Hospital of Yangzhou University were collected. The CT data was processed by 4D software program, and 10 groups of CT images were obtained. Respiratory gating plan and conventional radiotherapy plan were made for them. The target volume and dose of the two plans were compared, and the adverse reactions and efficacy of radiotherapy were observed within 3 months after treatment. Results Compared with the conventional plan, the volume of inner target area(ITV) and planning target area(PTV) under respiratory gating plan was smaller, and the dose received by 95% of PTV(D) was higher(P<0.05). The percentage of volume of normal lung tissue exposed to radiation doses greater than 20 Gy(V), the percentage of volume of normal lung tissue exposed to radiation doses greater than 5 Gy(V), mean dose of bilateral lung(MLD) and dose of spinal cord for 1 cm~3 volume(D) under the respiratory gating plan were significantly lower than those under the conventional plan(P<0.05). The follow-up results showed that the incidence rate of grade 1 and 2 radiation pneumonia was 25.0%, and the total effective rate was 65.6%. Conclusion 4D-CT combined with respiratory gating technology can be applied to SBRT for lung cancer, especially for patients with multiple lung metastases. It can accurately track the location of multiple tumors, ensure the effectiveness and accuracy of treatment, and reduce the occurrence of adverse reactions in surrounding normal tissues.