背景:氟-18去氧葡萄糖([lSF]FDG)已被廣泛應用於腫瘤偵測。本研究利用核研所動物用旋轉式正子造影系統(AROPET)及微觀自體射線攝影術(autoradiography)來觀察人類甲狀腺腫瘤動物模式中[I SF] FDG之動態吸收與分佈。

方法:人類甲狀腺腫瘤細胞皮下注射於二隻裸鼠右後腿內，並使腫瘤成長二個月，將小鼠以苯妥比鹽(pentobarbital)的mg/kg腹腔注射麻醉後，再將[lSF]FDG以尾靜脈注射入小鼠體內，注射的劑量分別為520�Ci及620 �Ci 0 [lSF]FDG注 射後，利用ARO-PET的上下偵檢器獲取二維平面影像進行動態造影研究，以每張影像30秒方式掃描四小時，獲得35X31矩陣排列。於動態造影後立即將小鼠犧牲，進行微觀自體射線攝影術及組織病理切片檢查。分別圈選腫瘤及對側大 腿區域畫出一時間-活度曲線圖。

結果:動態造影分析[lSF]FDG注射後0-4小時，結果顯示腫瘤組織對[lSF]FDG進行性且一致性的吸收增加趨勢，同時甲狀腺腫瘤之[lSF]FDG吸收約為對側大腿的二倍。微觀自體射線攝線術結果亦可見腫瘤細胞與周圍肉芽組織均有銀灰顆粒沈積，顯示這些組織有較高的[lSF]FDG吸收。

結論:動態造影與微觀自體射線攝影術實驗結果均顯示人類甲狀腺腫瘤對[lSF]FDG有進行性累積，本次研究結采建議ARO-PET掃描系統可適用於以二維平面模式影像進行[I SF] FDG之動態分布研究。

Background: Fluorine-18-2-deoxy-D-glucose (['8F]FDG) has been widespread used in tumor detection. This study investigated the dynamic accumulation and the distribution of ['8F]FDG in human thyroid cancer bearing nude mice with INER ARO-PET (Animal Rotating PET) scan and autoradiography

Methods: Human thyroid cancer cells were subcutaneously inoculated into 2 nude mice and allowed to grow for 2 months. The mice were anesthetized with pentobarbital (65 mg/kg; ip)， followed by administration of ['8F]FDG through the tail vein. The injected dose of ['8F]FDG was 520 Ci to one mouse， and 620 Ci to the other. Only the plannar images were acquired using the upper and lower detectors of the ARO-PET system for dynamic study. The ARO-PET scanner acquired 30 sec/frame dynamic planar images， with 35 x31 matrix size， for 4 h. Immediately after the dynamic image acquisition， the mice were sacrificed for micro-autoradiography and histopathological examination with H&E staining. A time-activity curve was generated by drawning regions of interest over the tumor and the contralateral side of thigh as the background control.
For correspondence or reprints contact: Pan-Fu Kao， M.D.， Department of Nuclear Medicine， Chang Gung Memorial Hospital and Chang Gung University， 199 Tung Hwa North Road， Taipei 105， Taiwan， R.O.C.Tel: (886)3-3281200 ext. 2622， Fax (886)3-3282619， E-mail: kaopanfu@adm.cgmh.org.tw

up to 4 h after injection of the radiotracer. The uptake of ['8F]FDG by the thyroid cancer was approximately twice higher than that observed on the background control. In consistent with the observed uptake of ['8F] FDG by ARO-PET， micro-autoradiography showed density of silver grains in the tumor and surrounding granulation tissue.

Conclusion: Dynamic analyses of ['8F]FDG planar imaging demonstrated progressive accumulation of ['8F]FDG in human thyroid tumors. The tumor uptake was about twice higher than the background at 4 h after injection of the radiotracer. Tumor uptake of ['8F]FDG was confirmed by micro-autoradiography performed on the same animal. The present studies suggest that the ARO-PET scanner can be used for ['8F]FDG dynamic distribution studies in small animals by a planar mode of imaging acquisition