PET/CT与CT在食管癌精确放射治疗靶区勾画中的应用研究

Application of PET/CT and CT in target volume delineation for precision radiotherapy of esophageal cancer

摘要:

目的 探究PET/CT与CT在食管癌精确放射治疗（以下简称放疗）靶区勾画中的应用效果。方法 采用分层抽样法选取2020年5月—2022年5月在新疆医科大学第三临床医学院放射治疗中心进行食管癌治疗的初治患者40例为研究对象。随机将患者分为对照组与研究组，各20例。对照组采用常规CT进行扫描，研究组采用PET/CT进行扫描，两组均为同一医师操作，医师根据同一固定体位下的CT扫描图像和PET/CT融合图像分别勾画靶区及其危及器官。对比2种成像数据下的临床靶区体积（GTV）和计划靶区体积（PTV）。以95% PTV为规定剂量60 Gy 30次，对比两组影像上的靶区受照剂量，双肺分别照射10 Gy（V₁₀）、20 Gy（V₂₀）、30 Gy（V₃₀）和平均剂量（MLD）；以30 Gy的容积（V₃₀）照射心脏，同时照射脊髓和气管。结果 与对照组相比，研究组勾画的GTV和PTV体积小（P <0.05）。研究组GTV Dmean、PTV Dmean均低于对照组（P <0.05）。研究组肺V₁₀、肺V₂₀、肺V₃₀、肺MLD、心脏V₃₀、脊髓、气管受量均低于对照组（P <0.05）。结论 PET/CT比单纯CT勾画靶区具有更好地针对性和清晰度，可提高靶区定位精度，改善靶区体积及损伤器官受照剂量，对完善我国公共卫生重大疾病防治规划、国家卫生保健体系具有重要意义。

Abstract:

Objective To investigate the effectiveness of applying PET/CT and CT in target volume delineation for precision radiotherapy of esophageal cancer.Methods A stratified sampling method was used to select 40 treatment-na?ve patients who visited the Radiation Therapy Center of the Third Clinical Medical College of Xinjiang Medical University for esophageal cancer treatment from May 2020 to May 2022 as the research subjects. These patients were randomly divided into a control group and a study group, with 20 cases in each group. The patients in the control group underwent conventional CT scans, while those in the study group underwent PET/CT scans. Both groups were operated by the same physician, who delineated the target volumes and the volumes of organs at risk based on CT scan images and PET/CT fusion images taken in the same fixed position. The gross tumor volume (GTV) and the planning target volume (PTV) were compared between the two types of imaging modalities. The prescribed dose was 60 Gy in 30 fractions to cover 95% PTV, and the doses delivered to the target areas were compared between the two groups based on the images. The percentages of the total lung volume exceeding 10 Gy (V₁₀), 20 Gy (V₂₀), and 30 Gy (V₃₀), the mean lung dose (MLD), the percentage of the heart volume exceeding 30 Gy (V₃₀), and the volumes of spinal cord and trachea receiving radiation were evaluated.Results Compared with the control group, the GTV and PTV delineated in the study group were smaller (P < 0.05). The GTV Dmean and the PTV Dmean in the study group were lower than those in the control group (P < 0.05). The lung V₁₀, V₂₀, and V₃₀, MLD, heart V₃₀, and the volumes of spinal cord and trachea receiving radiation in the study group were lower than those in the control group (P < 0.05).Conclusion PET/CT provides better accuracy and clarity in target volume delineation compared to CT alone. It enhances the positioning accuracy of the target volume, and lowers the target volumes and the volumes of organs at risk. It is of great significance for improving China's prevention and control programs for major public health issues and the national healthcare system.