Composite Dual Window Scattering Correction Technique In PET

Abstract

Most current energy spectrum based scattering correction techniques in PET suffer from source distribution dependencies. As an alternative method to compensate for these problems, we propose a composite dual energy window (CDW) scattering correction technique, which is based on using the scatter kernels from both the scatter and the photopeak windows. The CDW technique can be broken down to two steps: convolution and energy window correction. In the convolution part, we can obtain the first order scatter projections for both the photopeak and scatter windows by using the calibrated scatter kernels. Then we find the object dependent scatter ratio by dividing the convolution-estimated scatter projections. By this simple division, the overestimation of scatters during convolution is mostly canceled out. In the second step, we simply use the measured scatter profiles in the scatter window and the estimated scatter ratio to obtain the scatter projection in the photopeak window. The CDW technique is evaluated with a Monte Carlo simulation program which simulates the UGM PENN-PET scanner. The results indicate that this technique is better than both the deconvolution-subtraction with one iteration and dual window scattering correction techniques.