Radioactive iodine in thyroid medicine--how it started in Sweden and some of today's challenges.

In Sweden, radioactive iodine for thyroid diagnostics and therapy was introduced by Jan Waldenström (1906-1996) and Bengt Skanse (1918-1963). The paper describes the start of the clinical use of radioiodine, the various iodine isotopes available, measurement techniques and dosimetry. There are still problems to solve in relation to an optimal clinical use of radioiodine.

A generic model for 11C labelled radiopharmaceuticals for imaging receptors in the human brain.

A large number of radiopharmaceuticals labelled with 11C (half-time 0.340 h) are being developed for positron emission tomographic studies of different types of receptor in the human brain. For most of these agents, the available biokinetic data are insufficient to construct realistic compound-specific biokinetic models for calculating the internal radiation dose delivered to persons undergoing investigation.

Biokinetics of iodide in man: refinement of current ICRP dosimetry models.

A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection.

Biokinetics and radiation doses for carbon-14 urea in adults and children undergoing the Helicobacter pylori breath test.

The long-term biokinetics and dosimetry of carbon-14 were studied in nine adults and eight children undergoing carbon-14 urea breath test for Helicobacter pylori (HP) infection. The elimination of 14C via exhaled air and urine was measured with the liquid scintillation counting technique and with accelerator mass spectrometry. After the subjects had been given 110 kBq 14C-urea (children: 55 kBq) orally, samples of exhaled air were taken up to 180 days after administration and samples of urine were collected up to 40 days.

Application of accelerator mass spectrometry (AMS) for high-sensitivity measurements of 14CO2 in long-term studies of fat metabolism.

Long-term measurements of 14C in CO2 expired after ingestion of 14C-labelled triolein were performed using accelerator mass spectrometry (AMS). About 30% of a given amount of 14C-labelled triolein was catabolized rapidly, while the remaining 70% had a very slow turnover. The study shows the potential of the AMS technique for the study of the long-term biokinetics of 14C-labelled pharmaceuticals.

Effective dose from radiopharmaceuticals.

The effective dose, as defined by the International Commission on Radiological Protection (ICRP 1991), provides a possibility of expressing the radiation risk to patients undergoing different radiodiagnostic procedures by means of a single figure. This has been obtained by introducing organ or tissue weighting factors reflecting the radiation sensitivity of the organs. Such weighting factors were first published by the ICRP in publication 26 (1977), and have now been revised in publication 60 (1991).

Fate of bone grafts in acetabular roof reconstructions assessed by roentgenography and scintigraphy.

Autogeneic bone grafts--26 femoral heads, four femoral and two iliac bone grafts--were used in 32 total hip arthroplasties, mainly on patients with complete dislocation of the hip, to reconstruct deficiencies of the acetabular roof by a standardized procedure. At the follow-up examination after 24 to 101 months (median, 52 months), roentgenography demonstrated lateral resorption of the graft in 20 of 32 hips, but resorption involved bone support of the socket in only three of the hips. Analysis of serial roentgenograms showed that resorption was not a function of time.

Excretion of radionuclides in human breast milk after the administration of radiopharmaceuticals.

The fraction of injected activity that was excreted through the breast milk of nursing mothers at different times after the injection of various radiopharmaceuticals has been measured in 21 patients. For 99mTc-labeled radiopharmaceuticals the total excreted fraction was 10% for pertechnetate and 1.5-3% for MAA, plasmin, diethylenetriaminepentaacetic acid (DTPA), and methylene diphosphonate (MDP).

Glomerular filtration rate, autonomic nerve function, and orthostatic blood pressure in patients with diabetes mellitus.

Glomerular filtration rate (GFR) measured by the 51Cr-EDTA clearance method, autonomic nerve function evaluated by the heart rate reaction to deep breathing (E/I ratio) and to tilting (acceleration and brake indices), and orthostatic blood pressures were followed up after 5-7 yr in 43 patients with Type 1 diabetes. At follow up, 20 patients showed a decrease in GFR greater than expected. In the first study, these patients showed low E/I ratios and brake indices indicating vagal neuropathy, while the acceleration index fell, indicating sympathetic denervation, between the studies.

Effective dose equivalent from radiopharmaceuticals.

The concept of "effective dose equivalent", which was introduced by the International Commission on Radiological Protection (ICRP) for occupationally exposed workers, has also created the possibility of expressing by means of a single figure, the radiation risk to patients undergoing different medical radiodiagnostic procedures. In this study, we present the effective dose equivalent for various nuclear-medicine investigations. The figures given are primarily based on a review of data contained in the literature on the mean absorbed dose to various organs.

Radioactive dextran particles for studying circulation in animals.

Two types of dextran particles, (density 1.12 g X cm-3), ie chelating dextran particles (diameters 15.0 and 52.

Is CEA analysis of value in screening for recurrences after surgery for colorectal carcinoma?

The progress of 139 patients operated upon for cure of colorectal carcinoma, was followed postoperatively with a standardized protocol. A CEA test was performed for comparison with other parameters. Median observation time was four years.

Whole body measurements of sodium turnover in offspring of patients with sustained essential hypertension.

The elimination rate (percent per day) of injected 22Na using a whole body measurement technique was significantly lower (5.8 +/- 1.5) in normotensive or borderline hypertensive offspring of essential hypertensive patients than in 15 age- and sex-matched, normotensive controls (7.

Bone formation of transplanted autologous bone matrix in rabbit evaluated by technetium radionuclide bone imaging.

In adult rabbits a 12 mm piece of the radius was bilaterally resected and subsequently decalcified. One piece was placed in one of the radial defects and the other in a skin tube on the back. The other radial defect served as a control.

Abnormal whole-body and cellular (erythrocytes) turnover of 22Na+ in normotensive relatives of probands with established essential hypertension.

1. Whole-body elimination rate of 22Na+ was decreased in normotensive or borderline first-degree relatives of hypertensive probands. 2.

Evaluation of the microsphere method for determination of cardiac output and flow distribution in the rat.

The radioactive microsphere technique was applied to determine simultaneous cardiac output and flow distribution in the rat. Left ventricular injections of large numbers of microspheres were given, without significant adverse effects, allowing determination of flow to organs and tissues with low perfusion rates. In order to determine coronary blood flow it was necessary to excise the inner lining of the left ventricle, thus eliminating activity from deposits of microspheres.

Catabolic rate of alpha1-antitrypsin of of Pi types S, and MMalton and of asialylated M-protein in man.

1. Human alpha1-antitrypsin was isolated with preserved microheterogeneity from subjects of Pi types M, S and MMalton. The M-protein was partially (20%) and completely desialylated.

Studies in pharmacokinetics and tolerance of substances temporarily retained in the liver by microsphere embolization.

Earlier investigation has shown that a temporary arrest of arterial blood flow can be achieved by embolization with degradable microspheres. This study was made to investigate the change in pharmacokinetics, and drug tolerance which takes place when a substance is retained in the liver by a microsphere embolization. 14C-labelled inulin and 5-fluorouracil were studied.

Myocardial scintigraphy with 99mTc-pyrophosphate in patients with unstable angina pectoris.

A total of 400 patients, aged 25-82 years, admitted to the Coronary Care Unit due to clinical suspicion of acute myocardial infarction, were examined with 10 mCi 99mTc labelled to pyrophosphate. The examinations were carried out 4-120 hours post onset of symptoms, with a mobile gamma camera. Scintigrams were evaluated with regard to presence, localization and intensity of an uptake.

Metrizamide in urography. II. A comparison of 51Cr-EDTA clearance and metrizamide clearance in man.

In nine subjects undergoing urography with metrizamide measurements of total serum clearance of 51Cr-EDTA have been made before, during, and after the urography. During the urography both total serum clearances and renal clearances were determined for 51Cr-EDTA and metrizamide. The present study in man confirms the previous results from investigations in rabbits, that most of the intravenously injected metrizamide is excreted through the kidneys, that tubular reabsorption of metrizamide occurs and suggests that metrizamide might be used with advantage for urography.

Quantitative analysis of the distribution of 99mTc-labelled ethylene hydroxy diphosphonate in young rats.

The distribution of 99mTc-labelled ethylene 1-hydroxy-1,1-diphosphonate (EHDP) in young rats was studied 1, 3, 6 and 9 h after intraperitoneal injection. The concentration of 99mTc in bone was 8-10 times higher than that in the kidneys and 20-1000 times higher than those in other soft tissues. The concentration in bone remained constant throughout the observation time.

Catabolic rate of alpha1-antitrypsin of Pi type M and Z in man.

1. Human alpha1-antitrypsin was isolated from three Pi M and two Pi Z subjects without alteration of its microheterogeneity. The purified proteins were labelled with either 125I or 131I by a lactoperoxidase method.