objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

PURPOSE Radiotherapy for breast cancer includes different techniques and methods. The purpose of this study is to compare dosimetric calculations using TG-43 dose formalism and Varian Acuros™ BV (GBBS) dose calculation algorithm for interstitial implant of breast using metal catheters in high-dose-rate (HDR) brachytherapy, using (192)Ir. MATERIAL AND METHODS Twenty patients who were considere...

PURPOSE Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT), which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction. METHODS Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and...

Introduction: Accurate evaluation of femoral and tibial torsion is essential for children or adult with legs deformity, becuse incorrect legs morphogenesis can lead to pathological situation. CT scan is commonly used for the measurement of skeletal bone parameters. But, disability in imaging from standing and sitting posture and absorb dose of patients are deficits of this meth...

PURPOSE A recent reanalysis of the Collaborative Ocular Melanoma Study (COMS) medium tumor trial concluded that incorporating factors to account for anisotropy, line source approximation, the gold plaque, and attenuation in the Silastic seed carrier into the dose calculations resulted in a significant and consistent reduction of calculated doses to structures of interest within the eye. The aut...

Scatter radiation from portable and pediatric X-rays could pose a risk to radiographers, nearby patients, caretakers. We aim evaluate the spatial scatter distribution caretakers during common projections in X-rays. evaluated three-dimensional dose profiles of four three commonly used X-ray projections, respectively, by anthropomorphic phantoms probes. For X-ray, AP abdomen had highest recorded....

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique ...

Introduction SPECT projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. Backscatter constitutes a major part of the scatter contamination in lower energy windows. The current study is an evaluation of the effect of backscatter material on FWHM and image quality investigated by Monte Carlo simulation. Materials and Methods SIMIND program...