68Ga—DOTA—TATE在人体正常脏器内的分布特点

A pilot study on the biodistribution pattern of 68Ga-DOTA-TATE in normal organs of adults

目的回顾性研究68Ga-DOTA-TATE在人体内分布情况。 方法选取临床可疑而随访未发现肿瘤或病理证实为直径小于2 cm单发小肿瘤的患者106例，分析其68Ga-DOTA-TATE PET/CT显像的体内放射性分布。患者静脉注射55.2～220.0 MBq显像剂后17～100 min行PET/CT显像。用ROI法测量各脏器SUV。以单因素方差分析、两样本t检验进行统计分析。 结果（1）68Ga-DOTA-TATE在垂体内有特异性摄取，SUVmax 4.00±1.21；主要通过泌尿系统排泄，肾脏SUVmax 19.01±5.45；纵隔血池及肝脏SUVmax分别为0.93±0.33和7.69±2.26，大脑、小脑、肺和肌肉内放射性分布低于纵隔血池；肾上腺（SUVmax 7.61±3.42）及脾（SUVmax 8.63±2.31）与肝近似或略高，其余脏器（垂体、涎腺、甲状腺、胰腺、小肠、结肠、子宫、前列腺和骨）介于纵隔血池与肝脏之间。（2）9例患者胰腺钩突部位见灶性放射性摄取增高影，最高SUVmax 8.48，胰腺各段SUVmax及SUVmean差异均无统计学意义（F值：0.703、0.563，均P〉0.05）。（3）不同采集时间间隔（注射后50 min内与大于50 min）各脏器及胰腺各段SUV差异无统计学意义（t值：－0.09～1.75和－1.70～－0.42，均P〉0.05）。 结论68Ga-DOTA-TATE注射后短时间内在人体各脏器内放射性分布即达到相对稳定水平，脏器间分布有差异，存在与SSTR相关的分布特征，不随时间变化而变化。

Objective To retrospectively study the biodistribution of 6SGa-DOTA-TATE as a SSTR imaging agent in human subjects. Methods A total of 106 patients with suspected disease were enrolled in this study. All patients were histologically proven for having either a single tumor 〈2 cm or without evidence of tumor during follow-up. Patients underwent PET/CT whole-body scan 17-100 rain after intravenous injec- tion of 55.2-220.0 MBq 6SGa-DOTA-TATE. ROI was drawn for measuring SUV of tracer-avid pathologies. One-way analysis of variance and two-sample t test were used for statistical analysis. Results High 68 Ga- DOTA-TATE avidity was found in pituitary, with SUVm of 4.00：t= 1.21. Tracer was excreted mainly through urinary system resulting in highest uptake in the urinary tracts. The SUVm of kidney cortex was 19.01 ± 5.45. Mediastinal blood pool and liver SUVm were 0.93±0.33 and 7.69±2.26, respectively. Mild uptake of 6SGa-DOTA-TATE was found in the brain, cerebellum, lung and muscle, all lower than that of mediastinal blood pool. Moderate accumulation of 6SGa-DOTA-TATE （close to or slightly higher than liver） was found in adrenal gland and spleen, with SUV 7.61 ± 3.42 and 8.63±2.31, respectively. Other organs （pituitary, salivary gland, thyroid, pancreas, small intestine, colon, uterus, prostate and bone） showed tracer uptake in the range between those of mediastinal blood pool and liver. 6SGa-DOTA-TATE distribution in pancreas was not uniform. Nine patients had focal accumulation in the uncinate process of pancreas with highest SUVm~ up to 8.48. However, the SUVm and SUV in the rest of pancreas （head, neck, body and tail） showed insignificant difference （F values： 0. 703, 0.563, both P〉0.05）. 6s Ga-DOTA-TATE uptake in eachorgan reached equilibrium quickly after injection but with slight increase over time. The changes in SUV, however, showed insignificant difference among organs, including different parts of pancreas （ t values ： from -0.09 to 1.75, from -1.70 to -0.42, respectively, all P〉0.05）. Conclusions The biodistribution of 68Ga- DOTA-TATE reaches equilibrium shortly after intravenous administration and is stably maintained. The bio- distribution activities are organ-specific, and characteristic to that of SSTR concentration.