LAUSR

Abstract Background The collimators in which the various geometrical configurations have been suggested to optimize the sensitivity and resolution have a key role in acquiring the qualified images in nuclear medicine towards a better recognition of some diseases. Methods In this study, a new configuration as a geometrical combination of the conical, cylindrical and spherical (CCS) volumes for parallel-hole collimators (PCs) which is investigated by using the volumetric-parametric method has been introduced to enhance point spread function (PSF). The obtained PSF is evaluated via collimators response, which is derived from a radioactive point source. The configuration was simulated by MCNPX code at different amounts of energy from the point source together with the traditional collimator which contained only the cylindrical volume. Results The PSF will transmogrify from a delta function to a distribution that can correlate to a Gaussian distribution while increasing the scattered gamma rays. The simulation results shown that the PSF in CCS configuration is narrower than that of the cylindrical one at all the energies, which led to an enhancement in the resolution. Also, the theoretical results were agreement with the simulated ones. The higher the energy amount of the source, the wider the PSF becomes due to the higher penetration and scattering potency. Also, the percentage of scattering and penetration (S+P)% of the CCS collimator was less than the conventional PC one because of more undesirable photons elimination in the annexed conical-spherical denticles. The better the qualified image had a narrower PSF. Conclusion The suggested geometry and method may also be used to determine the exact attenuation coefficient of absorbers.