background vascular ring is less than 1% of congenital heart disease. double aortic arch (daa) is the most common form of it.  its detecting is important because of the effects of pressure on the esophagus and trachea. case report in this study, three children suffering from double aortic arch with symptoms of dysphagia and recurrent aspiration, which in two cases had led to cardiac arrest, wer...

Computed tomography (CT) is a widely used medical imaging modality. By rotating an x-ray tube and an x-ray detector around the patient, a CT scanner is able to measure the x-ray transmission from all directions and form an image of the patient’s interior. CT scanners in clinical use today all use energy-integrating detectors, which measure the total incident energy for each measurement interval...

The collective effective dose to the population from all x-ray examinations in Finland in 2005 was estimated. The numbers of x-ray examinations were collected by a questionnaire to the health care units (response rate 100 %). The effective doses in plain radiography were calculated using a Monte Carlo based program (PCXMC), as average values for selected health care units. For computed tomograp...

Background: The HU linearity is an essential parameter in a quantitative imaging and the treatment planning systems of radiotherapy. Objective: This study aims to evaluate the linearity of Hounsfield unit (HU) in applying the adaptive iterative dose reduction (AIDR) on CT scanner and its comparison to the filtered back-projection (FBP).Material and Methods: In this experimental phan...

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