Ljungberg M, Strand S E
Radiation Physics Department, University of Lund, Sweden.
J Nucl Med. 1990 Sep;31(9):1560-7.
A new scatter and attenuation correction method is presented in which Monte Carlo simulated scatter line-spread functions for different depth and lateral positions are used. A reconstructed emission image is used as an estimate of the source distribution in order to calculate the scatter contribution in the projection data. The scatter contribution is then subtracted from the original projection prior to attenuation correction. The attenuation correction method uses density maps for the attenuation correction of projection data. Simulation studies have been done with a clinically realistic source distribution in cylindrical, homogeneous water phantoms of different sizes and with photon energies corresponding to 201T1, 99mTc, and 111In. The results show excellent quantitative results with an accuracy within +/- 10% for most of the source positions and phantom sizes. It has also been shown that the variation in the event distribution within the source region in the images has been significantly decreased and that an enhancement in the contrast has been achieved.
提出了一种新的散射和衰减校正方法，该方法使用了针对不同深度和横向位置的蒙特卡罗模拟散射线扩展函数。使用重建的发射图像作为源分布的估计值，以便计算投影数据中的散射贡献。然后在进行衰减校正之前，从原始投影中减去散射贡献。衰减校正方法使用密度图对投影数据进行衰减校正。已经在不同尺寸的圆柱形均匀水体模中，针对与201Tl、99mTc和111In对应的光子能量，对临床实际的源分布进行了模拟研究。结果表明，对于大多数源位置和体模尺寸，定量结果非常出色，精度在+/- 10%以内。还表明，图像中源区域内事件分布的变化已显著降低，并且对比度得到了增强。
