Abstract
Position Emission Tomography (PET) is a non-invasive technique in nuclear medicine, which can provide physiological information using molecular tracers. As the 3D acquisition of PET data increases, random and scatter coincidence events are increasingly relevant issue. They cause a uniform distribution of background on the image and degrade the accuracy of quantitative analysis. The conventional correction method for random and scatter events are achieved by the delayed time window method and Single Scatter Simulation(SSS) method. However, they increase noise and decrease image accuracy. Beam stopper rotation method examines the feasibility of using beam stoppers (BS) for correcting non-true coincidence. The BS placed on the line of response (LOR) at two different locations rotated constant degrees, which absorbs a particular fraction of the true events. The non-true component, which can’t be stop at the LOR blocked by each stopper can be estimated. Assuming that the non-true radiation has a spatially slow-varying distribution, the whole non-true sinogram can be recovered using cublic-spline interpolation from these local measurements. BSR method reduces the effective sampling distance without increasing the stopper’s number. The study uses Monte Carlo (MC) simulation tools of 3-D PET, ”GATE” on a cold phantom to conduct the BSR method. The main advantage of this study is achieved well corrected effect at larger energy window. The non-true fraction of BSR method is 31.55% and is close to the result of Monte-Carlo simulation. In sum, BSR method is a convenience and effective non-true correction method for 3D PET.