title: The Effect of Parallel-hole Collimator Material on Image and Functional Parameters in SPECT Imaging: A SIMIND Monte Carlo Study.
abstract: The collimator in single-photon emission computed tomography (SPECT) is a critical component of the imaging system and plays an impressive role in the imaging quality. In this study, the effect of the collimator material on the radioisotopic image and its functional parameters was studied. The simulating medical imaging nuclear detectors (SIMIND) Monte Carlo program was used to simulate a Siemens E.CAM SPECT (Siemens Medical Solutions, Erlangen, Germany) system equipped with a low-energy high-resolution (LEHR) collimator. The simulation and experimental data from the SPECT imaging modality using (99m)Tc were obtained on a point source and Jaszczak phantom. Seventeen high atomic number materials were considered as LEHR collimator materials. In order to determine the effect of the collimator material on the image and functional parameters, the energy resolution, spatial resolution, contrast, and collimator characteristics parameters such as septal penetration and scatter-to-primary ratio were investigated. Energy spectra profiles, full width at half maximums (FWHMs) (mm) of the point spread function (PSF) curves, system sensitivity, and contrast of cold spheres of the Jaszczak phantom for the simulated and experiment systems have acceptability superimposed. The results of FWHM and energy resolution for the 17 collimators showed that the collimator made of 98% lead and 2% antimony could provide the best FWHM and energy resolution, 7.68 mm and 9.87%, respectively. The LEHR collimator with 98% lead and 2% antimony offers the best resolution and contrast when compared to other high atomic number metals and alloys.
authors.affiliation: Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Ahmadreza
authors.initials: A
authors.lastname: Azarm
authors.affiliation: Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Jalil Pirayesh
authors.initials: JP
authors.lastname: Islamian
authors.affiliation: Nuclear Medicine Unit, Department of Radiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Mahmoudian
authors.affiliation: Nuclear Medicine Unit, Department of Radiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Gharepapagh
keywords: Collimator material; Monte Carlo simulation; functional parameters; image quality; simulating medical imaging nuclear detectors; single-photon emission computed tomography