Contrast thresholds for detection of various iodine concentrations in subtraction CT and dual-energy CT systems.

Objective: To estimate the minimum iodine concentrations detectable in simulated vessels of various diameters for both subtraction computed tomography (CT) and dual-energy CT systems.

Methods: Fillable tubes (diameters: 1, 3, and 5 mm) were filled with a variety of iodine concentrations (range: 0-20 mg/ml), placed in the center of 28-mm cylindrical rods and surrounded with water. Rods with and without fillable tubes were placed in a 20-cm cylindrical solid-water phantom to simulate administration of iodine in blood vessels.

Comparison of metal artifact reduction using single-energy CT and dual-energy CT with various metallic implants in cadavers.

Objectives: The purpose of this study was to compare the effectiveness of metal artifact reduction using Single Energy Metal Artifact Reduction (SEMAR) and Dual Energy CT (DECT).

Materials And Methods: Six cadavers containing metal implants in the head, neck, abdomen, pelvis, and extremities were scanned with Standard, SEMAR, and DECT protocols on a 320-slice CT scanner. Four specialized radiologists blinded to acquisition methods rated severity of metal artifacts, visualization of anatomic structures, diagnostic interpretation, and image preference with a 5-point grading scale.

Impact of patient centering in CT on organ dose and the effect of using a positioning compensation system: Evidence from OSLD measurements in postmortem subjects.

The purpose of this study was to investigate the frequency and impact of vertical mis-centering on organ doses in computed tomography (CT) exams and evaluate the effect of a commercially available positioning compensation system (PCS). Mis-centering frequency and magnitude was retrospectively measured in 300 patients examined with chest-abdomen-pelvis CT. Organ doses were measured in three postmortem subjects scanned on a CT scanner at nine different vertical table positions (maximum shift ± 4 cm).

Current state of practice regarding digital radiography exposure indicators and deviation indices: Report of AAPM Imaging Physics Committee Task Group 232.

Beginning with the advent of digital radiography systems in 1981, manufacturers of these systems provided indicators of detector exposure. These indicators were manufacturer-specific, and users in facilities with equipment from multiple manufacturers found it a challenge to monitor and manage variations in indicated exposure in routine clinical use. In 2008, a common definition of exposure index (EI) was realized in International Electrotechnical Commission (IEC) International Standard 62494-1 Ed.

Determining Organ Doses from CT with Direct Measurements in Postmortem Subjects: Part 2--Correlations with Patient-specific Parameters.

Purpose: To generate empirical sets of equations that can be used to calculate patient-specific organ doses resulting from a group of computed tomographic (CT) studies by using data from direct dose measurements performed within a human body.

Materials And Methods: Organ dose measurements were obtained in eight postmortem female subjects. A chest-abdomen-pelvis protocol was used for this study.

Determining Organ Doses from CT with Direct Measurements in Postmortem Subjects: Part 1--Methodology and Validation.

Purpose: To develop a methodology that allows direct measurement of organ doses from computed tomographic (CT) examinations of postmortem subjects.

Materials And Methods: In this institutional review board approved study, the x-ray linear attenuation coefficients of various tissues were calculated from the mean CT numbers of images that were obtained in eight embalmed adult female cadavers and compared with the corresponding linear attenuation coefficients calculated from CT images obtained in eight living patients that were body mass index (BMI)-matched. Dosimetry was performed in three of the cadavers by accessing organs of interest and affixing partially sealed vinyl tubes inside them.

Workflow efficiency comparison of a new CR system with traditional CR and DR systems in an orthopedic setting.

Workflow efficiency is a crucial factor in selecting computed radiography (CR) versus digital radiography (DR) systems for digital projection radiography operations. DR systems can be more efficient, but present higher costs and limitations in performing some radiographic exams. A newly developed CR system presents a good alternative with its faster line-by-line instead of pixel-by-pixel image plate-scanning technology and a more efficient workstation.

Radiation exposure with use of the mini-C-arm for routine orthopaedic imaging procedures.

Background: The use of mobile fluoroscopic devices during orthopaedic procedures is associated with substantial concern with regard to the radiation exposure to surgeons and support staff. The perceived increased risks associated with large c-arm devices have been well documented. However, no study to date has documented the relative radiation risk associated with the use of a mini-c-arm device.

Evaluating radiographic parameters for mobile chest computed radiography: phantoms, image quality and effective dose.

Conventional chest radiography is technically difficult because of wide variations in tissue attenuations in the chest and limitations of screen-film systems. Mobile chest radiography, performed bedside on hospital inpatients, presents additional difficulties due to geometric and equipment limitations inherent in mobile x-ray procedures and the severity of illness in the patients. Computed radiography (CR) offers a different approach for mobile chest radiography by utilizing a photostimulable phosphor.

Enterprise-wide CR implementation: the Shands Healthcare System experience.

Major healthcare systems are comprised of hospitals and clinics of different sizes and locations. Many such enterprises are already using picture archiving and communication systems (PACS) and computed radiography (CR) in their main hospitals. The integration of other hospitals and clinics into PACS is a more complex problem.