Accuracy and limitation of energy-window based scatter correction techniques have been evaluated for myocardial 201Tl SPECT by means of Monte Carlo simulation. In particular, projection view-dependency of energy distribution of the scattered photons was evaluated. Two geometrical configurations were simulated: namely a homogeneous cylindrical radioactivity located asymmetrically in a homogeneou...

BACKGROUND The diagnosis of viable myocardium in the setting of ischemic left ventricular systolic dysfunction might indicate which patients have the greatest prognostic benefit from myocardial revascularization. Single-photon emission CT (SPECT) thallium-201 (201Tl) scintigraphy for the detection of viable myocardium is widely available in the community, but outcome data using this imaging mod...

UNLABELLED The present study assessed left ventricular performance during dobutamine stress measured using gated SPECT, and compared the results to myocardial perfusion and fatty acid metabolism. METHODS Thirty-six patients with myocardial infarction given (99m)Tc-sestamibi or (99m)Tc-tetrofosmin were examined by gated SPECT at rest and during dobutamine stress (4-20 microg x kg(-1) x min(-1)...

Myocardial perfusion imaging is generally performed as a static acquisition without regard for dynamic changes in the cardiac cycle. The effect of heart rate and ejection fraction on the appearance of left ventricular chamber size and wall thickness as perceived in 201Tl scintigrams has not, to our knowledge, been previously studied. A dynamic computer model of the left ventricle was constructe...

BACKGROUND Incomplete ST-segment resolution (STR) after successful primary angioplasty for acute myocardial infarction (AMI) is associated with a poor prognosis. We used intracoronary Doppler velocimetry to investigate whether incomplete STR after primary angioplasty is a marker of severe microcirculatory dysfunction. METHODS AND RESULTS Fifty patients with < or =12-hour AMI underwent success...

introduction: it is a common protocol to use 201tl for the rest and 99mtc for the stress cardiac spect imaging. theoretically, both types of imaging may be performed simultaneously using different energy windows for each radionuclide. however, a potential limitation is the cross-contamination of scattered photons from 99mtc and collimator x-rays into the 201tl energy window. we used a middle en...

We present dose calculations to the basal cell layer of the epidermis resulting from skin contamination by radionuclides used in nuclear medicine. Dose calculations were made using the computer code VARSKIN, as modified by us to include these radionuclides and to account for their monoenergetic electron emissions. Results indicate that basal skin doses (taken to be at a depth of 0.007 cm) are a...

Clinical value and limitation of thyroid imaging with 201T1C1 were studied. The positive rate of 201T1 was 82% in 22 malignant thyroid lesions and 46% in 37 benign lesions. A 201T1 positive image was obtained when a lesion was parenchymatous and a 201T1 negative one when it was cystic, filled with colloid or hyaline and had massive necrosis or bleeding. Thus 201T1 Cl localized in a parenchymato...

This study was undertaken to examine the ability of SPECT in differentiation of a pulmonary lesion suspecions of lung cancr. A total of 170 patients with suspected lung cancer were studied. A dose of Tl-201 chloride {148-296 MBq) was injected intravenously and tomographic early and delayed scans were obtained at 15 miniutes and 3 hours post injection, respectively. Delayed Tl-201 SPECT vi...