conclusions the automatic bolus-tracking method, results in higher contrast enhancement of the aorta and spleen at the portal phase, but has no effect on liver enhancement. however, bolus tracking is associated with reduced variability for liver enhancement among different patients. results forty-eight patients (23 male, 25 female, mean age=56.4±13.5 years) were included. the contrast enhanceme...

Introduction: Crosstalk is a leakage of X-ray or light produced in a matrix of X-ray detectors or array of photodiodes in one element to other elements affecting on image contrast and spatial resolution. In this study, we assessed X-ray crosstalk in a computed tomography (CT) scanner with small detector elements to estimate the effect of various parameters such as X-ray tube voltage, detector e...

introduction: in this study, arrangement of a low-cost optical tomography device compared to other methods such as frequency domain diffuse tomography or time domain diffuse tomography is reported. this low-cost diffuse optical imaging technique is based on the detection of light after propagation in tissue. these detected signals are applied to predict the location of in-homogeneities inside p...

A method for achieving quantitative single-photon emission computed tomography (SPECT) based upon corrections derived from x-ray computed tomography (CT) data is presented. A CT-derived attenuation map is used to perform transmission-dependent scatter correction (TDSC) in conjunction with non-uniform attenuation correction. The original CT data are also utilized to correct for partial volume ef...

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab-wooden dust (pine)-SP34 slab (SWS) heterogeneous phantom.  Materials and Methods: Th...

The current work describes an anthropomorphic beating heart phantom constructed as a tool for the assessment of technological advances in cardiac x-ray computed tomography (CT). The phantom is comprised of a thorax, a compressor system, an ECG system, a beating heart with tortuous coronary arteries, and the option to add or remove pathologies such as aberrant beats, stents, and plaques. Initial...

background and aims. cone-beam computed tomography (cbct) is an imaging system which has many advantages over computed tomography (ct). in ct scan, hounsfield unit (hu) is proportional to the degree of x-ray attenuation by the tissue. in cbct, the degree of x-ray attenuation is shown by gray scale (voxel value). the aim of the present study was to investigate the relationship between gray scale...

statement of the problem in order to replace lost tooth of patients, we use dental implants which are common. therefore, accurate measuring of bone height and width before placing implants is necessary. the aim of this study is evaluating the accuracy of linear and spiral tomography in careful determination of implant site sizes in comparison with gold standard (cbct). material and methods this...