in this research work, alpha particle detector is made using semi-insulating gaas. a surface barrier detector with a semi-insulating gaas substrate at room temperature with pressure of 10-4 torr under -particle radiation with 5.48 mev of am241 source, have been under investigation. energy resolution of 2 and 3 mm schottky diameter have been matured and compared with the effect of voltage varia...

objective(s): the energy resolution of a cadmium-zinc-telluride (czt) solid-state semiconductor detector is about 5%, and is superior to the resolution of the conventional anger type detector which is 10%. also, the window width of the high-energy part and of the low-energy part of a photo peak window can be changed separately. in this study, we used a semiconductor detector and examined the ef...

introduction: image quality and accuracy of in vivo activity quantification in spect are affected by collimator penetration and scatter components, especially in high energy imaging. these phenomena highly depend on the collimator characteristic and photon energy. the presence of penetrated and scattered photons from collimator in spect images degrades spatial resolution, contrast and image qua...

introduction: scatter radiation is one of the major sources of error in nuclear medicine data processing. different methods of scatter correction have been introduced in order to improve the quality of data. however the best method is to avoid recording of scatter photons in acquisition. the only difference between scattered and non-scattered photons is the energy. pulse height analyzer is the ...

introduction range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (pet). in this study, geant4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in pet imaging including 11c, 13n, 15o, 18f, 68ga, and 82rb. materials and methods gea...

introduction: acceptance test is a necessary procedure after spect system installation. the goal of this test is to reveal system's present condition, to compare it with manufacturer's specifications and also as a base for later tests. methods: this study investigated four spect systems in tehran. all of the quality control tests are performed on the basis of nema and iaea recommendations and b...

Introduction: Scatter radiation is one of the major sources of error in nuclear medicine data processing. Different methods of scatter correction have been introduced in order to improve the quality of data. However the best method is to avoid recording of scatter photons in acquisition. The only difference between scattered and non-scattered photons is the energy. Pulse height analyzer i...

Introduction Range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (PET). In this study, GEANT4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in PET imaging including 11C, 13N, 15O, 18F, 68Ga, and 82Rb. Materials and Methods GEA...

Introduction: Acceptance test is a necessary procedure after SPECT system installation. The goal of this test is to reveal system's present condition, to compare it with manufacturer's specifications and also as a base for later tests. Methods: This study investigated four SPECT systems in Tehran. All of the quality control tests are performed on the basis of NEMA and IAEA recommendations...