胸部肿瘤放疗后椎体对99Tcm-MDP的摄取表现及分析

目的 分析行胸部肿瘤放疗后全身骨显像所示椎体对99Tcm-亚甲基二膦酸盐（MDP）的摄取变化及其与临床放疗参数的相关性。 方法 回顾性分析2014年4月20日至2018年12月31日在山东省肿瘤医院进行胸部肿瘤放疗前后行全身骨显像的110例患者其中男性62例、女性48例，年龄（58.2±11.9）岁]的临床资料，包括临床病史、肿瘤因素及放疗计划等，通过半定量分析将骨扫描所示结果分为椎体摄取正常组和椎体摄取异常组。按照放疗前后骨显像时间间隔进行分组:60~120 d组（23例）、121~180 d组（30例）、181~240 d组（27例）、241~365 d组（30例）。组间比较采用χ2检验，采用二分类Logistic回归分析椎体对99Tcm-MDP摄取的改变及其与临床放疗因素的相关性；计算（T/N_前）?（T/N_后）/（T/N_前）（T为靶区受照中心3个完整椎体的99Tcm-MDP摄取值，N为靶区外3个正常椎体的99Tcm-MDP摄取值），绘制受试者工作特征（ROC）曲线，计算椎体对99Tcm-MDP摄取变化率的最佳诊断阈值。 结果 110例患者中，48例（43.6%）出现椎体局部对99Tcm-MDP摄取减低，出现摄取异常的椎体受照剂量为1039.5~4488.7（2139.5±839.8） cGy，放疗前后骨显像时间间隔最短为61 d，最长为326 d，中位时间为160 d；余62例（56.4%）患者椎体对99Tcm-MDP摄取未见异常。椎体99Tcm-MDP摄取减低程度与总放疗剂量（χ2=4.401，P＝0.036）、放疗次数（χ2=2.241，P＝0.027）、椎体受照剂量（χ2=5.913，P＝0.015）及放疗前后骨显像时间间隔（χ2=12.542，P=0.013）有统计学相关性，与年龄、性别、体重指数、单次放疗剂量、计划靶体积、计划靶体积剂量、椎体受照体积及放疗靶区中心至椎体中心的距离无统计学相关性；放疗前后骨显像时间间隔的组间比较发现，60~120 d、120~180 d组分别与181~240 d、241~365 d组相比，椎体对99Tcm-MDP的摄取差异均有统计学意义（χ2=3.850~15.429，均P<0.05），时间间隔＜180 d出现椎体99Tcm-MDP摄取异常的患者较多，占总摄取异常组的66.7%（32/48）。半定量分析评估椎体对99Tcm-MDP摄取异常的灵敏度为74.6%，特异度为82.9%。ROC曲线下面积为0.934，椎体99Tcm-MDP摄取异常的最佳诊断阈值为0.161。 结论 放疗后行骨显像的时间越早，椎体损伤的检出率越高；椎体摄取99Tcm-MDP的改变可在一定程度上反映患者椎体放射性损伤的程度。

Performance and analysis of vertebral 99Tcm-MDP uptake after chest tumor radiotherapy

Objective To analyze the changes in vertebral 99Tcm-medronate (MDP) uptake and the correlation with clinical radiotherapy parameters in chest tumor patients. Methods A retrospective study was conducted in 110 patients (including 62 males and 48 females aged 58.2 ± 11.9 years) who underwent chest tumor radiotherapy in Shandong Cancer Hospital from April 20, 2014 to October 31, 2018, and whole-body bone scan was performed before and after radiotherapy. The clinical information, tumor factors, and radiotherapy plan were analyzed using semiquantitative analysis. The results of the bone scan were divided into normal and abnormal vertebral uptake groups. In accordance with the time interval of bone imaging before and after radiotherapy, the patients were further classified into groups, namely, 60–120 (23 cases), 121–180 (30 cases), 181–240 (27 cases), and 241–365 (30 cases) days. The comparison among groups were analyzed using the χ2 test, and the statistical results were analyzed using the binary classification logistic regression. The change in the vertebral body 99Tcm-MDP uptake and the correlation with clinical radiotherapy parameters in chest tumor patients were discussed. The (T/N_before) ? (T/N_after)/(T/N_before) was calculated, and the receiver operating characteristic curve was drawn. The best diagnosis threshold of vertebral 99Tcm-MDP uptake abnormality was found. Results In 110 patients, 48 (43.6%) had local poor vertebral radioactivity uptake with minimum, maximum, and average vertebral exposure doses of 1039.5, 4488.7, and (2139.5±839.8) cGy, respectively. The shortest, longest, and median imaging interval was 61, 326, and 160 days, respectively. The remaining 62 patients (56.4%) had no obvious abnormal radioactive uptake. The degree of vertebral body uptake was correlated with the radiotherapy dose (χ2=4.401, P=0.036), radiotherapy frequency (χ2=2.241, P=0.027), vertebral body irradiation dose (χ2=5.913, P=0.015), and imaging interval before and after radiotherapy (χ2=12.542, P=0.013). No statistical correlation with age, gender, body mass index, single radiotherapy dose, planning target volume, planning target volume dose, vertebral irradiation volume, and distance from the radiotherapy center to the vertebral center was observed. In the grouped imaging intervals and compared groups, a difference was observed among 60–120, 121–180 days and 181–240, 241–365 days in vertebral body uptake (χ2=3.850–15.492, all P>0.05), and the abnormal vertebral 99Tcm-MDP uptake at intervals less than 180 days accounted for 66.7% (32/48). The sensitivity and specificity of evaluating the 99Tcm-MDP uptake abnormality were 74.6% and 82.9%, respectively. The area under the curve was 0.934 by the the receiver operating characteristic curve, indicating that (T/N_before)?(T/N_after)/(T/N_before) was good at evaluating the change rate of vertebral 99Tcm-MDP uptake, and the optimal diagnostic threshold for vertebral 99Tcm-MDP uptake abnormality was 0.161. Conclusions Early imaging time after radiotherapy results in high detection rate of vertebral injury. The change in vertebral body 99Tcm-MDP uptake can reflect the degree of radioactive vertebral damage to some extent.