Chronic ephedrine administration decreases brown adipose tissue activity in a randomised controlled human trial: implications for obesity.

Aims/hypothesis: Brown adipose tissue (BAT) activation increases energy expenditure and may have therapeutic potential to combat obesity. The primary activating and adaptive signal for BAT is via β-adrenergic signalling. We previously demonstrated that human BAT is acutely responsive to oral administration of the sympathomimetic, ephedrine.

Comparison of contemporaneous left ventricular ejection fraction (LVEF) obtained from planar gated cardiac blood pool scans (GCBPS) and Tl-201 gated myocardial perfusion scans (MPS) using a novel solid state dedicated cardiac camera.

Background: There is limited data on the concordance of left ventricular ejection fraction (LVEF) obtained via solid state dedicated cardiac cameras (SSD) and gated cardiac blood pool scans (GCBPS). This study aimed to examine the agreement of LVEF measured during GCBPS and Tl-201 myocardial perfusion scans (MPS) using SSD.

Methods: Seventy six patients were enrolled.

Ephedrine activates brown adipose tissue in lean but not obese humans.

Aims/hypothesis: Brown adipose tissue (BAT) activation increases energy consumption and may help in the treatment of obesity. Cold exposure is the main physiological stimulus for BAT thermogenesis and the sympathetic nervous system, which innervates BAT, is essential in this process. However, cold-induced BAT activation is impaired in obese humans.

Quantifying the effects of iodine contrast media on standardised uptake values of FDG PET/CT images: an anthropomorphic phantom study.

This study aimed to quantify the amount of change in Standardised Uptake Values (SUVs) of PET/CT images by simulating the set-up as closely as possible to the actual patient scanning. The experiments were conducted using an anthropomorphic phantom, which contained an amount of radioactivity in the form of Fluorodeoxyglucose (FDG) in a primary plastic test tube and one litre saline bags, including the insertion of bony structures and another two test tubes containing different concentrations of iodine contrast media. Standard scanning protocols were employed for the PET/CT image acquisition.

Radiation exposure and the justification of computed tomography scanning in an Australian hospital emergency department.

In an emergency department (ED), computed tomography (CT) is particularly beneficial in the investigation of high-speed trauma patients. With the advent of multidetector CT (MDCT) scanners, it is becoming faster and easier to conduct scans. In recent years, this has become evident with an increasing number of CT requests.

Better for ourselves and better for our patients: chronic disease management in primary care networks.

Capital Health in Edmonton, Alberta, implemented a system-wide chronic disease management model to support people with chronic disease and their primary care physicians. Groups of family physicians, in partnership with the health region, developed primary care networks to provide services that are customized to meet the priorities of the local community. Management of chronic disease is a cornerstone service, and diabetes management is the most fully developed program.

Contributions of subdiaphragmatic activity, attenuation, and diaphragmatic motion to inferior wall artifact in attenuation-corrected Tc-99m myocardial perfusion SPECT.

Background: Subdiaphragmatic activity and diaphragmatic motion both contribute to inferior wall artifacts in technetium 99m myocardial perfusion single photon emission computed tomography (SPECT).

Methods And Results: We used an anthropomorphic phantom with ventricular wall activity, liver/spleen inserts containing variable Tc-99m activity, and variable vertical (diaphragmatic) motion amplitude. SPECT and transmission scans were obtained on a GE Optima NX camera.

Staff exposure to ionizing radiation in a major trauma centre.

Background: The purpose of the present paper was to determine the safety of staff members with regard to ionizing radiation in a major trauma centre in a 19-month period.

Methods And Results: A group of five doctors, five nurses and a trauma orderly wore personal radiation monitors under lead aprons while at work. The highest individual cumulative result after 586 days was 0.

Effect of mechanically simulated diaphragmatic respiratory motion on myocardial SPECT processed with and without attenuation correction.

Unlabelled: The goal of this study was to assess the effect of diaphragmatic respiratory motion on inferior wall cold artifact in myocardial SPECT and to assess the ability of attenuation correction (AC) to correct for this artifact in the presence of diaphragmatic motion.

Methods: We used an anthropomorphic phantom with ventricular wall activity, variable ventricular caudal tilt, attenuating liver and spleen cold inserts, and variable vertical (diaphragmatic) motion amplitude and pattern. Cardiac SPECT images were acquired on a gamma camera with dual scanning transmission line sources and commercially available AC software (with scatter correction and iterative reconstruction).

A prospective blinded evaluation of exercise thallium-201 SPET in patients with suspected chronic exertional compartment syndrome of the leg.

This study compared the quantitative and qualitative results of leg thallium-201 single-photon emission tomography (SPET) imaging in patients with and without raised intracompartmental pressure associated with exercise-related leg pain. The purpose of this study was to clarify the aetiology of chronic exertional compartment syndrome (CECS), and to investigate the diagnostic applications of 201Tl SPET in CECS. Thirty-four study participants underwent compartment pressure testing (CPT) between March and August 2000.

The limited role of myocardial fluorine-18 fluorodeoxyglucose imaging in candidates for cardiac transplantation: a planar imaging study.

This study compares the incidence and extent of hibernating myocardium (defined by myocardial perfusion/metabolism mismatch) in 28 cardiac transplant candidates with ischaemic cardiomyopathy and in 16 other patients with coronary artery disease (CAD) undergoing viability assessment. It then reviews the impact of myocardial perfusion metabolism imaging on management decisions in the transplant candidates at 6 months after scintigraphy. Each patient underwent a planar myocardial thallium-201 and fluorine-18 fluorodeoxyglucose scan on a modified gamma camera.

Is planar thallium-201/fluorine-18 fluorodeoxyglucose imaging a reasonable clinical alternative to positron emission tomographic myocardial viability scanning?

This comparative study was performed to determine whether a conventional planar gamma camera optimised for 511-keV imaging can reliably assess myocardial viability using the fluorine-18 fluorodeoxyglucose (FDG) metabolic tracer previously developed for positron emission tomography (PET). Twenty-seven patients with severe ischaemic cardiomyopathy (mean left ventricular ejection fraction: 20% +/- 9%) having clinically indicated nitrogen-13 ammonia/FDG PET myocardial viability studies consented to resting, four-view, planar myocardial thallium-201 perfusion and FDG metabolism imaging. The resultant PET and planar perfusion/metabolism images (PPI) were independently assessed for FDG defect size and perfusion/metabolism mismatch, using a four-point scale, in each of four vascular regions: apex, circumflex, left anterior and posterior descending coronary artery territories.

Planar cardiac F-18 fluorodeoxyglucose imaging with a conventional gamma camera.

Objective: To examine the potential of an adapted gamma camera to image cardiac uptake of the positron emitting glucose analogue fluorine-18 fluorodeoxyglucose (FDG).

Design: Postprandial studies were performed in 19 patients (mean age, 56 +/- 9 years) with coronary disease and resting cardiac dysfunction who had undergone a routine clinical 7 min/view planar thallium-201 (Tl-201) stress reinjection or rest redistribution study. A glucose/insulin protocol was used and, an hour after FDG injection, 15-minute static planar myocardial images were acquired in the four views used for Tl-201 scanning.

Measurements of computed tomography radiation scatter.

This paper describes the measurement of scattered radiation from a computed tomography (CT) scanner in a clinical situation and compares the results with those obtained from a CT performance phantom and with data obtained from CT manufacturers. The results are presented as iso-dose contours. There are significant differences between the data obtained and that supplied by manufacturers, both in the shape of the iso-dose contours and in the nominal values.

Radiolytic breakdown of sodium iodide (131I) in sodium iodide (131I) capsules.

Sodium iodide (131I) capsules are widely used for both diagnosis and therapy. The radiochemical purity of both diagnostic and therapeutic capsules in use in Australia was studied by gel chromatography, high voltage electrophoresis and paper chromatography. It was found that in two of the three bands of therapeutic capsules examined, significant quantities of a labelled high molecular weight component was produced with the result that these capsules failed to meet British Pharmacopoeia, BP, and United States Pharmacopoeia, USP, requirements for radiochemical purity well before their quoted expiry time.