A Practical Method for Position-Dependent Compton-Scatter Correction in Single Photon Emission CT

A new practical method was proposed to subtract the count of scattered photons from that acquired with a photopeak window at each pixel in each planar image of SPECT. The subtraction is carried out using two sets of data: one set is acquired with a main window centered at photopeak energy and the other is acquired with two subwindows on both sides of the main window. The scattered photons included in the main window are estimated from the counts acquired with the sub-windows and then they are subtracted from the count acquired with the main window. Since the subtraction is performed at each pixel in each planar image, the proposed method has the potential to be more precise than conventional methods. For three different activity distributions in cylinder phantoms, simulation tests gave good agreement between the activity distributions reconstructed from unscattered photons and those from the corrected data.