First imaging result with an ultrahigh resolution stationary MR compatible SPECT system.
First imaging result with an ultrahigh resolution stationary MR compatible SPECT system.
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使用超高分辨率固定 MR 兼容 SPECT 系统获得第一个成像结果。
DOI：
10.1109/nssmic.2012.6551817
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Meng,LJ
中科院分区：
文献类型：
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作者：
Cai,L;Shen,ZM;Zhang,JC;Chen,CT;Meng,LJ
本文将介绍我们实验室研制的超高分辨率固定式磁共振兼容SPECT(MRC-SPECT)系统的设计和初步性能。MRC-SPECT系统基于第二代能量分辨光子计数(ERPC)CdTe探测器，该系统有几个关键特征。首先，将多达20个ERPC探测器组装成一个非常紧凑的环，提供足够的角度采样能力和相对较高的检测效率。探测器被支撑在由高强度聚酰胺结构制成的门架上，该结构使用3D打印构建。这种紧凑的系统可以在磁共振扫描仪内直接操作。该系统中使用的探测器模块提供了350keV的本征分辨率和约3-4keV的出色能量分辨率。每个ERPC探测器模块由4个像素化的CdTe探测器组成，总尺寸为4.5 cm×2.25 cm。其次，为该固定式SPECT系统开发了压铸铂针孔镶件和铸铅孔。每个探测器使用四个直径为300/500μm的针孔，所有针孔都安装在铸造的圆柱体铅孔管周围。引线孔管内径为6 cm，引线管厚度为16 mm。两个相对的探测器相距15.6 cm，该SPECT系统的放大倍数约为1.2。第三，建立了一个综合的强磁场电荷收集模型，考虑了SPECT图像中的磁场效应。该模型可以准确地预测探测器对伽马射线入射事件的能量和空间响应，从而有助于补偿强磁场引起的事件位置记录误差。在这一发展中，我们努力将系统中的磁性材料数量降至最低，以减轻对磁场不均匀的潜在干扰。
In this paper, we will present the design and preliminary performance of an ultrahigh resolution stationary MR compatible SPECT (MRC-SPECT) system that is developed in our lab. The MRC-SPECT system is based on the second-generation energy-resolved photon-counting (ERPC) CdTe detectors and there are several key features associated with this system. Firstly, up to a total of twenty ERPC detectors will be assembled as a very compact ring, which provides an adequate angular sampling capability and a relatively high detection efficiency. The detectors are supported on a gantry made of high strength polyamide structure constructed using 3-D printing. This compact system can be directly operated inside an MR scanner. The detector module used in this system offers an intrinsic resolution of 350μm and an excellent energy resolution of around 3-4kev. Each ERPC detector module consists of four pixelated CdTe detectors with a total dimension of 4.5cm×2.25cm. Secondly, a die-cast platinum pinhole inserts and cast lead apertures are developed for this stationary SPECT system. Four 300/500μm diameter pinholes are used for each detector and all pinholes are mounted around a casted cylinder lead aperture tube. The inner diameter of the lead aperture tube is 6cm and the lead tube thickness is 16mm. The opposite detectors are placed 15.6cm apart and the magnification factor of this SPECT system is about 1.2. Thirdly, a comprehensive charge collection model inside strong magnetic field has been developed to account for the magnetic field induced distortion in the SPECT image. This model can accurately predict the detector's energy and spatial response to gamma ray incident events and then help to compensate for the event position recording error due to the strong magnetic field. In this development, we have made an effort to minimize the amount of magnetic materials in the system to alleviate potential interference to magnetic field inhomogeneity.