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Our preliminary experimental and clinical results with 201Tl myocardial scanning are presented. 48 patients with normal coronary vessels, acute trasmural myocardial infarction, localized and diffuse coronary heart diseases and congestive myocardiopathy were investigated. Results of scans and the usual cardiological investigations were in good agreement thus justifying further use of 201Tl myocardial scintigraphy as an adjunctive method in cardiology.

A "region of interest" technique for measuring renal blood flow is described, using as Anger camera and selective intra-arterial injection of 133Xe and 99mTc. The sequence of measurements has the advantage of providing information on regional blood flow. The values for RBF and RBFD obtained with 133Xe agree with those in the literature. Selective determination of the RCBF with the "region of interest" technique using 133Xe was not possible. Mean transit time for 99mTc was calculated after correction of the 99mTc indicator dilution curve with respect to recirculation and background activity. All typer of pathological changes in the kidney showed a statistically significant increase in mean transit time when compared with a control group. In patients with uncomplicated essential hypertension, the mean transit time was signigicantly reduced. A comparison of the mean transit time of 99mTc with the haemodynamic parameters derived from the 133Xe studies, and experiments with pharmocologically induced vasoconstriction indicates that the mean transit time represents a measure of the RCBF.

The possibilities for nuclear medical investigation in the retroperitoneal space were extended by the introduction of the scintillation camera with an evaluation system. The diagnostic aid in diseases of the kidney (unilateral and bilateral nephropathies, shock kidney, stenosis of the renal arteries, aortic occlusion), suprarenals (Conn syndrome) and the skeleton of the entire body (diagnosis of metastases and non-malignant bone diseases) are reviewed. Scanning scintigraphy can be used in the identification of lymphnode metastases in negative (198 Au colloid) and positive (67 Ga) tumor contrast and in double radionuclide substraction techniques in pancreatic tumor and chronic pancreatitis. Clinical examples are demonstrated.

The biological distribution of 201Tl after intravenous injection was studied experimentally in 42 rats. It was found (see figure 1) that the kidneys showed the greatest affinity for 201Th, reaching an activity concentration of 6.6% per gramme of tissue, almost independently of time. Within the first 30 minutes of injection, myocardial activity exceeds that of the surrounding structures (10 min. p.i.: 4.24%/g; 30 min. p.i.: 2.58%/g). During this time the myocardium can be well demonstrated by "image processing". The relatively fast myocardial kinetics of 201Tl (half value time 33 minutes) make it necessary, strictly speaking, to use a scintillation camera. The clinical value of this method is illustrated by a number of case histories.

Today dual-photon absorptiometry (DPA) is recommended as the best procedure for diagnosing osteoporosis at an early stage considering its low cost, low radiation exposure and reasonable reliability. Cortical (neck of femur) and trabecular (L 2-4) bone mass has been determined repeatedly with DPA using 153Gd (NOVO Lab 22 a) in 545 females and 112 males with no evidence of bone diseases. Measured "normal" (age- and sex-related average) values for bone mineral content (BMC) differed significantly (p less than 0.01) from those of US inhabitants determined by the same equipment, i.e., they were on average about 30% lower, but matched well with corresponding results from Belgium. BMC-area was found the most suitable parameter both for cross-sectional and longitudinal studies, since it is independent of height and weight. But there is still need to reduce the overlap and improve accuracy and reproducibility for making decisions after shorter intervals. Assessment of the individual mineral loss and fracture risk by comparison with average values remains problematical due to the wide range of "normal" BMC values, and in women additionally due to the variable onset of menopause. For estimations of the individual fracture risk of elderly patients BMC should not be normalized on age, because at the age of 65 half of the women had "pathologic" values, i.e. were below the so-called "osteoporosis threshold". Comparison of the individually measured postmenopausal BMC with average values of premenopausal women and with BMC values normalized to their menopausal age may be helpful approaches to overcoming these difficulties.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative studies between radiological (equals R; x-ray, thermography, angiography) and nuclear medical examinations (equals NM; scanner-, scintillation camera-sequential scintigraphy) in 339 patients with different bone diseases led to the following results: Thermography proved to be inferior to scanning in detecting of bone diseases. Angiography was the procedure of choice in detecting malignant bone tumors. Sequential scintigraphy performed by means of the Anger-HP-scintillation camera and Intertechnique-Cine-System allowed to establish the kinetic behaviour of tumors: an early increased TcPoP accumulation was observed in tumors with high perfusion (sarcoma), a late accumulation in those with low perfusion (osteoid osteoma).