Introduction: The main purpose of this study was to compare transient ischemic dilation (TID) ratios in SPECT-low dose CT and SPECT Myocardial Perfusion Imaging (MPI) by application of different quantitative programs and quantify the possible shift in the upper normal limits of TID ratio in the SPECT-CT MPI. Methods: 149 Patients with low pre-test probability for coronary artery disease (CAD),...

introduction: the main purpose of this study was to compare transient ischemic dilation (tid) ratios in spect-low dose ct and spect myocardial perfusion imaging (mpi) by application of different quantitative programs and quantify the possible shift in the upper normal limits of tid ratio in the spect-ct mpi. methods: 149 patients with low pre-test probability for coronary artery disease (cad),...

RATIONALE AND OBJECTIVES We aimed to evaluate whether implementation of a low-dose computed tomography (CT)-guided lung biopsy protocol, with the support of individual radiologists in the section, would lead to immediate and sustained decreases in radiation dose associated with CT-guided lung biopsies. MATERIALS AND METHODS A low-dose CT-guided lung biopsy protocol was developed with modifica...

Within the past 2 decades, the number of CT examinations performed has increased almost 10-fold. This is in large part due to advances in multidetector-row CT technology, which now allows faster image acquisition and improved isotropic imaging. The increased use, along with multidetector technique, has led to a significantly increased radiation dose to the patient from CT studies. This places i...

The operation of the bowtie filter in x-ray CT is correct if the object being scanned is properly centered in the scanner's field-of-view. Otherwise, the dose delivered to the patient and image noise will deviate from optimal setting. We investigate the effect of miscentering on image noise and surface dose on three commercial CT scanners. Six cylindrical phantoms with different size and materi...

Background Radiation dose about 400 times that of standard thoracic computed tomography (CT) in comparison with chest X- ray resulting in different approaches to decrease radiation dose have been established in the last few years to prevent possible side effects especially in children, such as low dose protocols. The aim of this study was assessment of clinical v...

Introduction: Nowadays, magnetic resonance imaging (MRI) in combination with computed-tomography (CT) is increasingly being used in radiation therapy planning. MR and CT images are applied to determine the target volume and calculate dose distribution, respectively. Since the use of these two imaging modalities causes registration uncertainty and increases department w...

Introduction: The aim of this retrospective study was to evaluate the variations in delivered dose to the bladder, rectum, and femoral heads of prostate cancer patients during a course of treatment by image-guided radiation therapy (IGRT). Materials and Methods: Overall, 15 patients with prostate cancer were selected and. Each week, for each patient five consecutive cone beam computed tomograph...

A patient dose distribution was calculated by a 3D multi-group S N particle transport code for intracavitary brachytherapy of the cervix uteri and compared to previously published Monte Carlo results. A Cs-137 LDR intracavitary brachytherapy CT data set was chosen from our clinical database. MCNPX version 2.5.c, was used to calculate the dose distribution. A 3D multi-group S N particle transpor...

What challenge? CT has developed dramatically: scanning is faster, images are better, applications have grown and, of course, radiation doses have come down, have they not? Well, no, actually; quite the contrary in fact. When CT was new it was appreciated that it was a relatively high dose technique but there was overriding clinical justification for using it; in the brain no technique could ap...