Lonn A, Cottrall M, Simons H
Eur J Nucl Med. 1979 Aug 1;4(4):251-9. doi: 10.1007/BF00304880.
Experimental studies have been made of the impulse response and noise characteristics of a tomographic system using a gamma camera. Fourier transform, deconvolution and iterative methods have been used with a CDC 6600 computer to reconstruct images from data obtained for various experimental arrangements of sources in a cylindrical phantom. It is shown that with an appropriate attenuation correction the impulse response in the reconstruction is substantially constant, independent of the position of the source in the phantom and that the reconstruction technique used is of secondary importance. The resolution obtained for the impulse response and the relative noise level throughout the 'non image' part of the reconstructions is shown for different experimental situations. The measured variance in the reconstruction of an extended uniform activity source was found to be somewhat below the theoretical value except at high count densities (above 1,000 counts per image element) where the limit of accuracy of the reconstruction is shown to be imposed by the variation in the camera sensitivity over the field of view.
已对使用伽马相机的断层扫描系统的脉冲响应和噪声特性进行了实验研究。利用傅里叶变换、反卷积和迭代方法，借助CDC 6600计算机从圆柱形体模中源的各种实验布置所获得的数据重建图像。结果表明，通过适当的衰减校正，重建中的脉冲响应基本恒定，与源在体模中的位置无关，并且所使用的重建技术是次要的。针对不同的实验情况，给出了重建的“非图像”部分中脉冲响应的分辨率和相对噪声水平。发现除了在高计数密度（每图像元素超过1000计数）时，扩展均匀活性源重建中的测量方差略低于理论值，此时重建精度的限制表明是由相机在视场内灵敏度的变化所施加的。
