Scopinaro F, Massari R, Varvarigou A D, D'Alessandria C, Trotta C, Di Santo G P, Soluri A
Department of Nuclear Medicine, La Sapienza University of Rome, Rome, Italy.
Q J Nucl Med Mol Imaging. 2007 Jun;51(2):204-10.
The aims of this study were: 1) to perform brain single photon emission computed tomography (SPECT) in anesthetized rats with high resolution cameras (HRC) equipped with parallel hole collimation resolution of about 1 mm (HRC1) and 2 mm (HRC2); 2) to assess when and with which radio-tracer HRC1 SPECT shows advantages over HRC2.
We used two multicrystal HRCs with parallel square hole collimators, whose pure tungsten septa closely fit the crystals, in turn matched with a 4 inch2 position sensitive photomultiplier. HRC1 showed 1.1 mm and HCR2 2.1 mm resolution at collimator contact. HRCs performed 180 degrees semi-circular orbits around the head of rats: image reconstruction occurred with ordered subsets expectation maximization algorithms. Resolution of SPECT was measured with a Derenzo Phantom, resulting 1.4 mm for HRC1 and 2.3 mm for HRC2. Three rats were studied with [(99m)Tc]HMPAO, 3 rats with [(99m)Tc]bombesin (BN) and 48 h later with [(123)I]ioflupane (DaTSCAN). SPECT studies were reviewed by two experienced operators.
Technetium-99m-HMPAO SPECT showed similar images with HRC1 and HRC2. The uptake of BN by amygdale, hippocampus and olfactory tract was detected by both cameras. DaTSCAN SPECT with HRC1 showed detailed image of the tail of the caudatus: this image was not obtained with HRC2. DaTSCAN and BN SPECT showed amygdale with both HRCs. However, only the central nucleus of amygdale takes up DaTSCAN, whereas central, lateral and basolateral amygdaloid nuclei express BN receptors. Only HRC1 SPECT showed amygdale larger with BN than with DaTSCAN.
Spatial resolution of 1.4 mm is appropriate to detect selected subcerebral structures.
本研究的目的为：1）使用配备平行孔准直器、分辨率约为1毫米（HRC1）和2毫米（HRC2）的高分辨率相机（HRC），对麻醉大鼠进行脑单光子发射计算机断层扫描（SPECT）；2）评估HRC1 SPECT在何时以及使用何种放射性示踪剂时比HRC2具有优势。
我们使用了两台配备平行方孔准直器的多晶体HRC，其纯钨隔板与晶体紧密贴合，依次与一个4英寸²位置灵敏光电倍增管匹配。HRC1在准直器接触处的分辨率为1.1毫米，HCR2为2.1毫米。HRC围绕大鼠头部进行180度半圆形轨道运动：图像重建采用有序子集期望最大化算法。用Derenzo体模测量SPECT的分辨率，HRC1为1.4毫米，HRC2为2.3毫米。对3只大鼠用[（99m）Tc]HMPAO进行研究，3只大鼠用[（99m）Tc]蛙皮素（BN）进行研究，48小时后用[（123）I]碘氟烷（DaTSCAN）进行研究。SPECT研究由两名经验丰富的操作人员进行评估。
锝-99m-HMPAO SPECT在HRC1和HRC2上显示出相似的图像。两台相机均检测到杏仁核、海马体和嗅束对BN的摄取。HRC1的DaTSCAN SPECT显示出尾状核尾部的详细图像：HRC2未获得此图像。DaTSCAN和BN SPECT在两台HRC上均显示出杏仁核。然而，只有杏仁核中央核摄取DaTSCAN，而杏仁核中央、外侧和基底外侧核表达BN受体。只有HRC1 SPECT显示BN作用下的杏仁核比DaTSCAN作用下的更大。
1.4毫米的空间分辨率适合检测选定的脑下结构。
