Computed tomography is associated with exposing patients with high radiation doses. This study was conducted to evaluate the effect of reducing the rotation time to reduce the dose without compromising the image quality. Two types of CT scanners were involved in this study: a 4-slice and a 16-slice scanner. A significant reduction in CTD Ivol and DLP were observed with the 4-slice scanner, with...

The acquisition of diagnostic cardiovascular computed tomography (CT) images requires careful preparation of the patient before scanning. Guidelines for patient preparation are largely dictated by scanner capabilities and the technical limits they impose on patient-specific characteristics. The objective of this paper is to highlight procedures for patient screening, premedication, instruction,...

We present an image overlay system that assists in surgical needle insertions inside conventional CT scanners. The device is mounted on the gantry of the CT scanner and consists of a flat LCD display and a semi-transparent mirror. In the preoperative calibration process the overlay system and the imaging plane of the scanner are registered. As a result, looking at the patient through the mirror...

This paper presents the results from initial testing of a new method for georeferencing airborne multispectral scanner imagery. The method is called "parametric modeling with image-to-image matching" (PMIIM). The method takes an error prone estimate of the aerial platform’s trajectory as input, and outputs a corrected trajectory. The corrected trajectory can then be used to georeference the air...

Airborne laser scanner raw data are unstructured and irregular points which need intensive post processing. The first step is the separation of valuable points which lie on the ground surface (ground points) from outliners which are located above it (non-ground points). Another task is the extraction of structure lines from the laser scanner. Structure lines play an important role for the const...

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...

    Background: Since pulmonary angiography is the only non-invasive method for diagnosing pulmonary embolism, the use of radiation reduction methods without affecting the quality of images seems necessary. One of the simplest reasons for unnecessarily increasing of patient exposure is repetitive imaging due to poor image quality. Therefore, it is necessary to identify and ...

A new method for coding scanned halftone images is proposed. It is information-lossy, but still preserving the image quality, compression rates of 16-35 have been achieved for a typical test image scanned on a high resolution scanner. The bi-level halftone images are filtered, in phase with the halftone grid, and converted to a gray level representation. A new digital description of (halftone) ...

The importance of shape reconstruction is increasing in many areas such as RPD (Rapid Product Development) and reverse engineering. Typical data in these areas are mainly classified as the shape data measured by a laser scanner and the data extracted from the CT image. The goal of this research is to realize three-dimensional shape construction by showing a possible way to analyze input image d...