Characterization of the Scattered Radiation Fraction in PET or SPECT Cameras with a Novel Phantom Design

The measurement of characterization of scattered fraction in PET cameras has been difficult. A novel phantom based on mathematical symmetry has been designed and built to measure the scattered fraction anywhere in the images of PET and SPECT cameras for a uniformly distributed circular source. This measurement can be used to characterize the scattered fraction of these cameras. Only one data collection is necessary. The phantom is circular with 20cm diameter and made up of polystyrene. A sector of 18 degrees is cut out to carry the radioactivity of interest. The scattered background fraction F(x,y) for every image point (x,y) in a circular uniform activity distribution with the same diameter can be derived from the image counts in the radioactive sector, and the summation of all the counts on a narrow circular strip passing through (x,y) in the image of this proposed phantom.