Mizuta Tetsuro, Kitamura Keishi, Iwata Hiroshi, Yamagishi Yoshiyuki, Ohtani Atsushi, Tanaka Kazumi, Inoue Yoshihiro
Research and Development Department, Medical Systems Division, Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan.
Ann Nucl Med. 2008 Jun;22(5):447-55. doi: 10.1007/s12149-008-0127-2. Epub 2008 Jul 4.
In this study, we evaluated the performance of a newly commercialized small-animal positron emission tomography (PET) scanner, ClairvivoPET, which provides significant advantages in spatial resolution, sensitivity, and quantitative accuracy.
This scanner consists of depth of interaction detector modules with a large axial extent of 151 mm and an external (137)Cs source for attenuation correction. Physical performances, resolution, sensitivity, scatter fraction (SF), counting rate including noise equivalent count (NEC) rate, quantitative accuracy versus activity strength, and transmission accuracy, were measured and evaluated. Animal studies were also performed.
Transaxial spatial resolution, measured with a capillary tube, was 1.54 mm at the center and 2.93 mm at a radial offset of 40 mm. The absolute sensitivity was 8.2% at the center, and SFs for mouse-and rat-sized phantoms were 10.7% and 24.2%, respectively. Peak NEC rates for mouse-and rat-sized uniform cylindrical phantoms were 328 kcps at 173 kBq/ml and 119 kcps at 49 kBq/ml, respectively. The quantitative stability of emission counts against activity strength was within 2% over 5 half-lives, ranging from 0.6 MBq to 30 MBq. Transmission measurement based on segmented attenuation correction allowed 6-min and 10-min scans for mouse-and rat-sized cylindrical phantoms, respectively. Rat imaging injected with (18)F-NaF resulted in visibility of fine bone structures, and mouse imaging injected with (18)F-D-fluoromethyl tyrosine demonstrated the feasibility of using this system to obtain simultaneous time activity curves from separate regions, such as for the heart and tumors.
ClairvivoPET is well suited to quantitative imaging even with short scan times, and will provide a number of advantages in new drug development and for kinetic measurement in molecular imaging.
在本研究中，我们评估了一款新商业化的小动物正电子发射断层扫描（PET）扫描仪ClairvivoPET的性能，该扫描仪在空间分辨率、灵敏度和定量准确性方面具有显著优势。
该扫描仪由轴向范围达151毫米的相互作用深度探测器模块和用于衰减校正的外部（137）铯源组成。对其物理性能、分辨率、灵敏度、散射分数（SF）、包括噪声等效计数（NEC）率在内的计数率、定量准确性与活度强度的关系以及透射准确性进行了测量和评估。还进行了动物研究。
用毛细管测量的横向空间分辨率在中心处为1.54毫米，在径向偏移40毫米处为2.93毫米。中心处的绝对灵敏度为8.2%，小鼠和大鼠尺寸模型的散射分数分别为10.7%和24.2%。小鼠和大鼠尺寸均匀圆柱形模型的峰值NEC率分别在173 kBq/ml时为328 kcps和在49 kBq/ml时为119 kcps。发射计数相对于活度强度的定量稳定性在5个半衰期内（范围从0.6 MBq到30 MBq）在2%以内。基于分段衰减校正的透射测量分别允许对小鼠和大鼠尺寸的圆柱形模型进行6分钟和10分钟的扫描。注射（18）F-NaF的大鼠成像显示出精细骨结构的可见性，注射（18）F-D-氟甲基酪氨酸的小鼠成像证明了使用该系统从心脏和肿瘤等不同区域获取同步时间-活度曲线的可行性。
ClairvivoPET即使在短扫描时间下也非常适合定量成像，并且将在新药开发和分子成像的动力学测量中提供许多优势。
