Improvement of Quality of SPECT Images in Dual Advanced Compton Camera System

In single photon emission CT, one of the disadvantages of a data acquisition system is low efficiency. This is caused by the use of a collimator, which decreases the geometrical data collection efficiency to less than 0.01 of the photons emitted from a radionuclide. To overcome this problem an advanced Compton camera (ACC) was proposed by Tanimori.This camera detects the entering direction of a photon to the detector with the Compton scattering phenomenon, and the direction is analyzed with the information of the position of Compton scattering, moving direction of a recoiled electron and the energy deposited in the second detector where the whole energy of the scattered photon is released. We developed a reconstruction algorithm for the ACC and evaluated the quality of the reconstructed images in our previous work. In those studies we simplified the reconstruction model and did not consider interactions of emitted gamma rays with the object in which the radionuclide distributes. In this paper we investigated the effect of interactions between the object and primary photons emitted from the source. The simulation results showed that the spatial resolution of reconstructed imeges and the accuracy of dose distribution improved with the proposed method.修士(工学)法政大学 (Hosei University