In present PET/CT scanners, PET attenuation correction is performed by relying on the information given by CT scan. In the CT-based attenuation correction methods, dual-energy technique (DECT) is the most accurate approach, which has been limited due to the increasing patient dose. In this feasibility study, we have introduced a new method that can implement dual-en...

Introduction: Using computed tomography (CT) is increasing significantly in Iran and worldwide. Reduction of CT's radiation dose is a critical concern. The aim of this study was evaluating the effect of localizer kVp on spiral CT images when the tube current modulation (TCM) is activated. Materials and Methods: A special wedding cake phantom with circular in...

We investigated how varying the x-ray tube voltage and image receptor input exposure affected image quality and patient radiation doses in interventional neuroradiologic imaging. Digital subtraction angiography (DSA) images were obtained of a phantom with 1 mm diameter vessels containing iodine at concentrations between 4.5 and 50 mg/cc. The detection threshold concentration of iodine was deter...

Purpose: The purpose of the current work was experimental investigations of the mean breast dose and volume dose distributions with and without adaptive filtration. Adaptive filtration of the x-ray beam is used in dedicated breast CT to reduce dynamic range requirements on the detector, and to improve image quality. The adaptive filter has a predetermined shape, it is placed after the x-ray sou...

PURPOSE Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors...

INTRODUCTION Quality assurance programmes in diagnostic radiology have been increased in the last years due to the fact that the extensive use of X-rays in medicine for diagnosis of injuries and diseases represents the largest manmade source of public exposure to ionizing radiation (1). The assessment and control of the performance characteristics of X-ray generators and tubes is an essential p...

A steady-state flow model was used to optimize methods of data analysis, to investigate variables that affect the time-density curves, and to determine the accuracy of transit-flow measurements with digital subtraction angiography. The most accurate data were obtained by using a small region of interest placed within the vessel, averaged data acquisition, and a gamma-variate fit applied to the ...

OBJECTIVES To evaluate the image quality and radiation dose of submillisievert standard-pitch CT pulmonary angiography (CTPA) with ultra-low dose contrast media administration in comparison to standard CTPA. MATERIALS AND METHODS Hundred patients (56 females, 44 males, mean age 69.6±15.4 years; median BMI: 26.6, IQR: 5.9) with suspected pulmonary embolism were examined with two different prot...