Abstract
In nuclear medicine, the two major molecular imaging modalities namely are single photon emission tomography (SPECT) and positron emission tomography. Spatial resolution performance in PET and SPECT is related to a number of different factors. A general observation is that improvements in SPECT resolution are effectively only limited by technology (e.g., collimator design), whereas in PET imaging, two physics-related limitations, namely positron range and photon non-collinearity, ultimately limit system resolution. The purpose of this work is to simulate the application of dual photons computed tomography (DuPECT) which is considered to combine the benefits of SPECT and PET at the same time. It is expected to alter the problem of the high cost of isotopes used in PET. They are generated from the cyclotron and their half-life are too short to use. Also to obtain higher resolution compared to same isotopes in SPECT. The slit, hole collimators and the isotope In-111 were used in the DuPECT method. In-111 disintegrates and emits two γ photons with 171keV and 245 keV energy by over 99.99%. The data that would be used to reconstruct images by calculating the intersection of a plane and a line is from collimating the emitted photons by slit and hole collimators and obtaining the coincidence by the coincidence circuit in DuPECT system. The intersection is also where the isotope decayed. The simulation results show that the concept of DuPECT method is feasible if the isotope would emit two photons. The spatial resolution is also better than SPECT. Furthermore, the reconstructed image on DuPECT could be real time image. But there are still some problems. Nevertheless, DuPECT still has lots of possibilities in the future.