一种用于同时进行高分辨率单光子发射计算机断层扫描/正电子发射断层扫描的新型簇状多针孔技术的性能特征。
Performance characteristics of a novel clustered multi-pinhole technology for simultaneous high-resolution SPECT/PET.
作者信息
Miwa Kenta, Inubushi Masayuki, Takeuchi Yasuto, Katafuchi Tetsuro, Koizumi Mitsuru, Saga Tsuneo, Sasaki Masayuki
机构信息
Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba, 263-8555, Japan,
出版信息
Ann Nucl Med. 2015 Jun;29(5):460-6. doi: 10.1007/s12149-015-0966-6. Epub 2015 Apr 19.
OBJECTIVE
Versatile emission computed tomography (VECTor) for small-animal imaging enables fully simultaneous SPECT/PET image acquisition based on clustered multi-pinhole collimation. The present study experimentally evaluated the detailed performance characteristics of the clustered multi-pinhole system for simultaneous (99m)Tc and (18)F imaging from the user perspective.
METHODS
Spatial resolution, sensitivity, count rate linearity were determined for the VECTor system (MILabs). Two hot-rod micro-resolution phantoms with 6 sectors were created to test the resolution of (99m)Tc and (18)F. Sensitivity and count rate linearity were measured by scanning (99m)Tc and (18)F point sources positioned at the center of the field of view. Furthermore, we quantified the influence of (18)F on (99m)Tc SPECT images. The ratios of SPECT counts on the (99m)Tc-only and simultaneous (18)F-(99m)Tc at various time points were evaluated as a function of the (18)F-to-(99m)Tc activity concentration ratio.
RESULTS
The 0.5-mm hot-rods can be visually distinguished in the (99m)Tc image, and 0.8-mm rods for (18)F remained clearly visible. The point-source sensitivity was 2800 cps/MBq for (99m)Tc and 2899 cps/MBq for (18)F, respectively. Count rates up to 120,000 cps for one bed position were linear for the activity. Spill-over from (18)F into (99m)Tc SPECT images was negligible when the activity concentration of the administered (18)F solution exceeded that of the (99m)Tc solution by up to a factor of 2.
CONCLUSIONS
We evaluated the performance characteristics of the VECTor that lead to determination of the optimal administered doses of (99m)Tc and (18)F tracers. We found that the VECTor achieved high resolution and high sensitivity as well as good (99m)Tc and (18)F linearity. Simultaneous SPECT/PET imaging with (99m)Tc and (18)F tracers, and stand-alone (99m)Tc and (18)F imaging using clustered-pinhole collimators is feasible and practical for a wide range of research applications using small animals.
目的
用于小动物成像的多功能发射计算机断层扫描（VECTor）能够基于簇状多孔径准直实现完全同步的单光子发射计算机断层扫描（SPECT）/正电子发射断层扫描（PET）图像采集。本研究从用户角度通过实验评估了用于同时进行⁹⁹ᵐTc和¹⁸F成像的簇状多孔径系统的详细性能特征。
方法
测定了VECTor系统（MILabs）的空间分辨率、灵敏度、计数率线性。制作了两个带有6个扇区的热棒微分辨率模型，以测试⁹⁹ᵐTc和¹⁸F的分辨率。通过扫描位于视野中心的⁹⁹ᵐTc和¹⁸F点源来测量灵敏度和计数率线性。此外，我们量化了¹⁸F对⁹⁹ᵐTc SPECT图像的影响。评估了在不同时间点仅⁹⁹ᵐTc时的SPECT计数与同时进行¹⁸F - ⁹⁹ᵐTc时的SPECT计数之比作为¹⁸F与⁹⁹ᵐTc活度浓度比的函数。
结果
在⁹⁹ᵐTc图像中可以直观地分辨出0.5毫米的热棒，在¹⁸F图像中0.8毫米的热棒仍清晰可见。⁹⁹ᵐTc的点源灵敏度分别为2800 cps/MBq，¹⁸F为2899 cps/MBq。对于一个床位位置，高达120,000 cps的计数率对于活度呈线性关系。当给予的¹⁸F溶液的活度浓度超过⁹⁹ᵐTc溶液的活度浓度高达2倍时，¹⁸F对⁹⁹ᵐTc SPECT图像的溢出效应可忽略不计。
结论
我们评估了VECTor的性能特征，这些特征有助于确定⁹⁹ᵐTc和¹⁸F示踪剂的最佳给药剂量。我们发现VECTor实现了高分辨率、高灵敏度以及良好的⁹⁹ᵐTc和¹⁸F线性。使用⁹⁹ᵐTc和¹⁸F示踪剂进行同步SPECT/PET成像，以及使用簇状针孔准直器进行单独的⁹⁹ᵐTc和¹⁸F成像，对于广泛的小动物研究应用是可行且实用的。
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