[en] Thallium-201 myocardial scintigraphy was performed in patients with congenital heart defects to determine whether, by quantification of right ventricular isotope uptake, one could assess the degree of right ventricular hypertrophy and so predict the level of right ventricular pressure. It is shown that quantitative analysis of myocardial imaging with thallium-201 is of use clinically in patients with congenital heart defects, in assessing the severity of pulmonary stenosis or the presence of pulmonary artery hypertension. (author)

[en] Clinical decisions regarding 3-D activity distributions of Tl-201 in the myocardium are made from interpretations of various projections having 2-D impulse rate densities. Problems arise e.g., if in anterior view a small anterior infarct which is superimposed on a cylinder of healthy myocardium masks a posterior defect, the activity of which is attenuated in addition. As an approach to the solution of this problem the left ventricle is modelled as an ellipsoid of revolution, lying in a Cartesian coordinate system with origin in one focus. Length of semi-axes and position of the ellipsoid in 3-D are calculated as follows: Impulse rate densities of Tl-201 scans are displayed at least for two views (better: ant., LAO 30⁰, LAO 60⁰, left lat.) on a computer display. The contours of the left myocardium are approximated by 2 computer generated ellipses (projection of an ellipsoid on a plane has elliptical shape). For each ellipse length of semi-axes and focus positions are determined. Using these data size and position of the ellipsoid in the chest are calculated. The geometrical object thus obtained is divided into 10 segments. It then can be projected with its segmental concentration of activity on any plane with inhomogeneous background activity and absorption included. For each projection of all segments impulse rate densities measured are compared to those calculated for the ellipsoidal model. The extension of zones with decreased Tl-uptake in different projections can thus be estimated by comparison with the (theoretically) calculated impulse rate densities. Examples, showing identification, localization and sizing of perfusion defects are given

[en] The subject of this article is the perfusion scintigraphy of the myocardium. The technique and the clinical application of thallium-201-scintigraphy are discussed. Furthermore also new imaging techniques and radiopharmaceutics are dealt with. (R.A.B.). 16 refs.; 4 figs

No abstract available

[en] In order to investigate possible mutagenetic effects of in vivo exposure to low levels of ionizing radiation used in nuclear medicine, the authors examined hypoxanthine guanine phosphoribosyl transferase (hprt) mutant fraction (MF) and chromosome aberration (CA) frequency in 24 nuclear medicine patients before and after injection of thallium-201. The mean MF of the thallium-201-exposed cohort was 5.2±4.4 x 10^-6 before injection exposure. No significant difference in MF was observed 24 h later. In 11 patients who were studied on a 3rd occasion, 30 days after thallium-201 exposure, there was again no significant difference in post-exposure as compared with the pre-exposure MF. The frequency of CA in peripheral blood lymphocytes was not significantly different, comparing pre- and 24h to 1 month post-radionuclide exposure . Thus, thallium-201 exposure was not associated with significant elevations in MF or CA frequency in lymphocytes of exposed individuals. (author). 40 refs.; 3 tabs

[en] A detailed investigation was performed in ten patients who, out of 119 patients with abnormal thallium myocardial images, showed a discordant thallium uptake in the anterior and left lateral views. It was concluded that when interpreting the discordant uptakes, it is necessary to divide the antero-lateral wall into anterior and lateral segments. The lateral segment is the best seen in the anterior view and the anterior segment in the left lateral view. Similarly, the inferior-posterior region should be divided into right and left halves. The right half is seen best in the anterior view and the left half in the left lateral view. (U.K.)

[en] Two non-invasive methods are compared used in the diagnosis of myocardial ischaemia, i.e. precordial exercise mapping of the ST segment and after load ²⁰¹Tl scintigraphy of the myocardium.High sensitivity of mapping (89.3%) and of ²⁰¹Tl scan (92.9%) was found compared to the findings on the coronary arteries. The specificity of both methods was lower (57.1%). Both methods give similar results in diagnosis of myocardial ischaemia; for localization the affection site thallium scintigraphy of the myocardium is preferably used. (author). 2 figs., 2 tabs., 23 refs

No abstract available

[en] Scintigraphic myocardial imaging, using Thallium-201, finds its most rational application if the sensitivity and specificity of the test are used combined with the prevalence of the disease in a given age group. Clinical data remains invaluable in assuring a good interpretation in myocardial imaging

No abstract available