Nuclear-Medizin最新文献

The distributions of 4 hour 132I neck uptake and 20 minute 99mTcO4 thyroid uptake in euthyroid patients were found to conform closely to a log normal distribution, from which a statistical normal range may be obtained. More accurate discriminatory values for determining thyroid status may be established by plotting intersecting distribution curves for hypo-, hyper- and euthyroid groups. Subdivision by age and by the presence or absence of a palpable thyroid reveals considerable variations from which a series of more accurate discriminatory values may be established for these subgroups. For Free Thyroxine Index (T4RT3 index) more accurate discriminatory values were also obtained by similar methods; while no significant variations related to age or palpable thyroid were observed, subdivision of the patients into two groups referred as suspected hypothyroidism and suspected hyperthyroidism yielded a further small improvement in accuracy.

Tc-99m pyridoxylidene glutamate has proven to be an excellent biliary scanning agent, far superior in many respect to the commonly used I-131 rose bengal. The preparation of the compound as previously reported by Baker et al is too time consuming and requires the use of an autoclave which is not available in most nuclear medicine departments. In our facility, we have been preparing similar compounds using several aldehydes and monosodium glutamate to make labeled complexes having the same pharmacological characteristics. The mixture of monosodium glutamate, aldehyde, and Tc-99m pertechnetate is made slightly alkaline, purged with helium, and placed in a sealed vial. The vial, which is protected by a wire basket, is then heated in a laboratory oven at 130 degrees C for a period of 15 to 20 minutes. During this time, the technetium is reduced to a lower valence state and bound to the complex formed. Chromatographic data show that these compounds are chemically similar to that previously reported. The compounds prepared concentrate in the gall bladder of the rabbit in less than 10 minutes. Kinetic studies have been performed on dogs with a scintillation camera and small digital computer to measure rates of blood clearance, liver and gall bladder uptake, and excretion into the intestine. The aldehyde -- glutamate complex promises to be a useful scanning agent for the diagnosis of biliary and hepatocellular diseases.

Radio-iron utilization was nearly normal in these patients, only bilateral nephrectomized patients showed a reduced radio-iron utilization. Red blood half-life span was shortened in all patients, well corresponding to the degree of anemia. Parameters of erythropoesis like plasma iron clearance, bone marrow transit time, erythron iron turnover, non erythron iron turnover and hemolysis iron turnover failed to quantitate disorders of red blood cell regeneration in these patients. No defect in red blood cell enzyme activity could be demonstrated. Enzymes of glycolysis were increased corresponding to the reduced erythrocyte half-life span.

Kinetics and clinical studies of bone scintiscanning with 99mTc-pyrophosphate in 92 patients with certified diagnosis allowed the following conclusions: 1. After i.v. injection 99mTc-pyrophosphate is distributed in 3 compartments, from which it is cleared with biological half-lives of 32.7 minutes, 5.1 hours and 22.54 hours respectively. The relative size of these compartments is 1 : 3 : 6. After application of the substance, an initially high renal excretion with a consecutive exponential drop can be observed. The optimal period for scintigraphic studies seems therefore to be from 3-6 hrs, as at this time there is still an adequate activity in bone structures, while the low background activity yields a good contrast on scintiscans. 2. The clinical results of bone scintigraphy with 99mTc-pyrophosphate with 88.6% correct diagnoses can be considered as "very good". This feature can partly be attributed to an improved correlation of radiographic and scintigraphic images by the use of a specially designed, combined radiographic-photoscanning detector system. 3. Preliminary results concerning the quantitative uptake of 99mTc-pyrophosphate in fractures of the extremities suggest, that the quantitative analyses of the registered data can provide valuable prognostic information in traumatic, inflammatory and neoplastic bone lesions.

A simple and rapid method for the synthesis of 3-chloromercury-2-hydroxipropyl-urea has been described. It has been concluded that highest yields are obtained by the synthesis of 197HgO and allyl urea in the ratio of 2.5 : 1. Stability of the final preparation was investigated after thermal sterilization and standing at room temperature. It has been proved that the inorganic mercury-197 is not released. Radiochemical purity was controlled by chromatographic method using pyridine, n-butanol and water (3 : 10 : 3 v/v) as a solvent. The results obtained indicate that the preparation is applicable for human use.

The use of the first of a new class of chelating agents for the binding of metal ions to macromolecules as a novel approach to radiopharmaceutical labeling is described. Advantages are mild reaction conditions, large variety of accessible radionuclides and reactive groups, and separation of synthetic organic chemistry from radiochemistry. Human serum albumin and bovine fibrinogen labeled with 111Indium using this technique were relatively stable in vitro and in vivo, showed little alteration in function, and have potential as tumor localizing agents in humans.

The formation of two different 99mTc-Sn-pyrophosphate complexes was determined by evaluation of their in vivo distribution in rats. It was found that formation of a 2 : 2 Sn : PyP complex, which is bone seeking, is depending as well on the pyrophosphate as on the hydrogen ion concentration in the equilibrium. On the contrary, formation of a 2 : 1 Sn : PyP complex, which shows no bone affinity but concentrate in the kidneys, is hydrogen ion independent and occurs even at very low pyrophosphate concentrations. The probable structure of these complexes is discussed.

In a study with numerous samples of serum we compared 5 Digoxin RIA and evaluated the reliability of tests by simultaneous determinations. There were found considerable differences in the determinations with the various RIA for the same serum; evident differences also were recorded in the recovery and in the reproducibility of the assays. Among some other sources of error the dependence of temperature and of the duration of the dextran-charcoal separation were observed; therefore, the charcoal incubation is recommendable at 4 degrees C. Each laboratory which is able to perform the determinations of digoxin concentrations in the serum should declare its own range for the therapeutic and toxic levels for the used RIA in collaboration with the clinicians.

A polynomial fitting technique suitable for small computers has been developed for calculation of the muscle blood flow function by the 133Xe clearance method. An application of the method for blood flow measurements in the lower limbs during hyperaemia is presented. The calculated maximum blood flow and peak time values were closely correlated with the manually elicited results.

The relative solubility coefficient of 133Xe and the tissue-blood partition coefficient for the aqueous humour vitreous body, conjunctiva and external eye muscles of the rabbit were determined in vitro at 37 degrees C and at various haematocrit values. The partition coefficient for haematocrit 40 was: for the aqueous humour 0,49 ml/ml, for the vitreous body 0,50 ml/ml, for the conjunctiva 0,81 ml/g and for the external eye muscles 0,77 ml/g. It was found that the solubility of 133Xe in rabbit erythrocytes is about 50 per cent higher than that in human red cells. The consequences of this fact for the precision of blood flow measurements by the method of tissue clearance are discussed.