Sitek A, Gullberg G T, Di Bella E V, Celler A
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California, USA.
J Nucl Med. 2001 Nov;42(11):1704-12.
Nuclear medicine renal studies can be performed using slow-rotation SPECT, but reconstruction of such data is largely underdetermined.
A new method of reconstruction of data acquired using slow camera rotations was developed. In this method we used a factor model of the data in which the factors and factor coefficients were determined by modeling their relationship directly with the projection measurements. This was done by solving a least-squares problem that fits the projections of factors and factor coefficients to the projection data with nonnegativity constraints imposed on the solution. The method was tested on computer simulations and applied to experimental renal (99m)Tc-mercaptoacetyltriglycine canine and patient studies.
Computer simulations showed that the extracted time-activity curves of kidneys agreed well with the simulated curves for data with noise levels similar to those in the experimental studies. In the canine study, the method showed that >2 factors were necessary to adequately reproduce the kinetics of the kidney. In the patient study, the method was able to extract separate factors that correspond to the kidney cortex and the kidney pelvis.
The computer simulation, the canine study, and the patient study all show that reconstructions of the data obtained with 1 detector displayed artifacts, whereas reconstructions of the data obtained with 2 and 3 detectors were free of artifacts. Computer simulations showed that the method gives accurate results that allow quantitation.
核医学肾脏研究可使用慢旋转单光子发射计算机断层扫描（SPECT）进行，但此类数据的重建在很大程度上是欠定的。
开发了一种重建使用相机慢旋转获取的数据的新方法。在该方法中，我们使用了数据的因子模型，其中因子和因子系数通过直接对其与投影测量值的关系进行建模来确定。这是通过解决一个最小二乘问题来完成的，该问题将因子和因子系数的投影与投影数据进行拟合，并对解施加非负约束。该方法在计算机模拟上进行了测试，并应用于实验性肾脏（99m）锝 - 巯基乙酰三甘氨酸犬类和患者研究。
计算机模拟表明，提取的肾脏时间 - 活性曲线与噪声水平与实验研究相似的数据的模拟曲线吻合良好。在犬类研究中，该方法表明需要大于2个因子才能充分再现肾脏的动力学。在患者研究中，该方法能够提取出分别对应于肾皮质和肾盂的因子。
计算机模拟、犬类研究和患者研究均表明，使用1个探测器获得的数据的重建显示出伪影，而使用2个和3个探测器获得的数据的重建无伪影。计算机模拟表明该方法给出了允许定量的准确结果。
