定量 ECT：单光子和符合探测（F-18，B+511keV）的探测器响应恢复系数和线性度比较。

Quantitative ECT: Comparison of Recovery Coefficient and Linearity of Detector Response for Single Photon and Coincidence Detection (F-18, B+ 511 keV).

出版信息

IEEE Trans Med Imaging. 1986;5(4):177-82. doi: 10.1109/TMI.1986.4307776.

DOI:10.1109/TMI.1986.4307776

Abstract

The response characteristics of two tomographic systems were compared for imaging of positron emitters: a) a SPECT system with a 3/8 in crystal and 511 keV detector shielding, equipped with a specially designed 511 keV collimator, and b) a PET V system using coincidence detection. SPECT transverse plane resolution was 19 mm FWHM and 35 mm FWTM for a radius of rotation of 16 cm. Corresponding resolution for PET was 14 mm FWHM and 28 mm FWTM. Transverse images through a phantom containing cylindrical sources of various cross sections and uniform activity were obtained for each detector. The measured count density or recovery coefficient was found to decrease with source size, the dependence being similar for both systems. The theoretical values for recovery coefficients were calculated by convolution of a Gaussian fit to the SPECT resolution (FWHM, FWTM) values with the uniform cross section of each source. This simple mathematical model confirmed that the recovery coefficient dependence on source size was primarily related to the limited resolution of the detector. Experimental measurements demonstrated that the SPECT resolution for volume sources was sufficient for quantitation, although some limitations exist with respect to source sizes smaller than the detector resolution.

摘要

比较了两种正电子发射体断层成像系统的响应特性

a）配备专门设计的 511keV 准直器的 3/8 英寸晶体和 511keV 探测器屏蔽的 SPECT 系统，和 b）使用符合探测的 PET V 系统。SPECT 横向平面分辨率为 19mm FWHM 和 35mm FWTM，旋转半径为 16cm。相应的 PET 分辨率为 14mm FWHM 和 28mm FWTM。对于每个探测器，通过包含具有不同横截面和均匀活性的圆柱形源的体模获得横向图像。发现测量的计数密度或恢复系数随源尺寸的减小而减小，两种系统的依赖性相似。通过将高斯拟合到 SPECT 分辨率（FWHM、FWTM）值与每个源的均匀横截面进行卷积，计算出理论恢复系数值。这个简单的数学模型证实，恢复系数对源尺寸的依赖性主要与探测器的有限分辨率有关。实验测量表明，SPECT 对体积源的分辨率足以进行定量，尽管对于小于探测器分辨率的源尺寸存在一些限制。