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At least 73 records · Page 4Linked to original sources
PubMed1985

Gold-195m: a steady-state imaging agent for venography that gives blood velocity measurement.

Gold-195m has found applications in first-pass studies for investigating both right and left ventricular activity as well as lung transit. Owing to its reasonably short half-life of 30 sec we have found it particularly useful for imaging leg veins up to and including the inferior vena cava. Its short half-life prevents recirculation activity from appearing, so continuous perfusion into a superficial foot vein and application of ankle tourniquets yield a steady-state image of the deep veins, with particularly good resolution. Its decay pattern along a vessel is very sensitive to blood velocity, so measurement of activity at various points on a vein in a computer static image can give velocity values that reveal abnormalities due to partial or complete thrombosis. The radiation dosimetry of 195mAu used in this way is lower than contrast and technetium-99m macroaggregated albumin [( 99mTc]MAA) venography, making it particularly useful for investigating deep vein thrombosis (DVT) in pregnancy.

Abdomen↗
PubMed1984

[Noninvasive first-pass study of the heart with the short-lived radionuclide gold 195m].

The new shortlived radionuclide Aurum 195 m (T1/2: 30.5 sec) has been used for 1,596 first-pass examinations of 792 patients. During first-pass the same maximum count rates of an average of 300,000 cts/sec and after background subtraction the same enddiastolic counts over the left ventricle averaging 10,000 cts/sec can be achieved as with the previously used Tc-99 m pertechnetate injections. The short half-life and fast regeneration of Au-195 m within 3 minutes allow repeated, subsequent injections with significant reduction in radiation exposure. Half of the studies were done at rest and exercise, one third in two oblique projections, RAO and LAO. Examinations in two projections improve the information facilitating the localization of ischemic or infarcted LV-regions particularly with respect of septal and/or lateral extension. Strictly lateral dysfunction may sometimes be only recognizable in the second LAO-projection. The RAO-view best discriminates the extension along the anterior and infero-posterior wall.

Evaluation Studies as Topic↗
PubMed1978

Krypton-81m.

Explore the source record for details and available documents.

Computers↗
PubMed2005

Cross-section measurement of the 169 Tm p,n reaction for the production of the therapeutic radionuclide 169 Yb and comparison with its reactor-based generation.

The radionuclide (169)Yb (T(1/2)=32.0 d) is potentially important for internal radiotherapy. It is generally produced using a nuclear reactor. In this work the possibility of its production at a cyclotron was investigated. A detailed determination of the excitation function of the (169)Tm(p,n)(169)Yb reaction was done over the proton energy range up to 45 MeV using the stacked-foil technique and high-resolution gamma-ray spectrometry. The integral yield of (169)Yb was calculated. Over the optimum energy range E(P)=16-->7 MeV the yield amounts to 1.5 MBq/micro Ah and is thus rather low. A comparison of this production route with the established (168)Yb(n,gamma)(169)Yb reaction at a nuclear reactor is given. The (169)Yb yield via the reactor route is by several orders of magnitude higher than by the cyclotron method. The latter procedure, however, leads to "no-carrier-added" product.

Isotope Labeling↗
PubMedDate not supplied

[Radiation health evaluation of generators of short-lived radionuclides].

Up-to-date 99Tcm generators commonly used in clinical diagnostic nuclear medicine departments have been assessed to compare their radiation hygienic characteristics. Based on the differentiated approach some foreign-made models of generators producing short-period radionuclides have been studied. The unified scheme of the total operating process has been built allowing the evaluation of working conditions and radiation doses for personnel at every operating stage, some experimental results are given. Conditions causing the maximum radiation doses are revealed, and some recommendations for the improvement of working environment and the reduction of the radiation dose are developed.

Environmental Exposure↗
PubMed1988

Radiation dose to various age groups from radionuclide impurities in 99mTc-pertechnetate (fission product 99Mo generator) radiopharmaceutical preparations.

Radionuclide impurities of radiopharmaceuticals do not provide any diagnostic information, but contribute to the radiation dose to the patient. For 99mTc, even small amounts of long lived radionuclide impurities may contribute significantly to the dose from 99mTc itself. In this preliminary study, estimates have been made for the radiation dose to specific organs and for the effective dose equivalent from impurities in 99mTc-sodium pertechnetate prepared from fission product 99Mo. In addition to 99Mo, 131I, 103Ru, 89Sr and 90Sr at maximum permissible levels as stipulated in the European Pharmacopoeia, 110mAg and 239Pu were taken as representative nuclides for beta-gamma emitters and alpha emitters. Using all of these radionuclides at such maximum permissible levels of impurity as stated in the European Pharmacopoeia, the total contribution from the impurities to the effective dose equivalent is approximately 30% of the effective dose equivalent from 99mTc-pertechnetate. In terms of specific organs, the liver and kidneys can receive doses of 3-4 times and 1-3 times the dose from 99mTc-pertechnetate itself. Although these are worst case calculations, a consistent approach should be reconsidered to limit the additional effective dose equivalent from impurities to e.g. 10% of the effective dose equivalent from 99mTc itself.

Adolescent↗
PubMed1978

Analysis of wall motion abnormalities of the heart and great vessels by computer generated cine-radionuclide-equilibrium study.

Cardiac wall motion was evaluated in 54 patients by ECG-gated blood pool scintigraphy (GBPS) and computer assisted cine-radionuclide-equilibrium study (CRES). The cine format in CRES enhances the subtle aspects of great vessel and cardiac chamber motion and volume abnormalities. An off-line system using a general purpose computer permitted CRES to be initiated in smaller nuclear medicine facilities without large financial investiments.

Adult↗
PubMed1984

Patterns of ventricular contraction in patients with conduction abnormality studied by radionuclide angiocardiography.

The phase image generated by radionuclide angiocardiography illustrates the regional timing of ventricular wall motion. In this study the phase image was used to investigate the patterns of ventricular contraction in 103 subjects with either normal hearts or a conduction abnormality. In 38 normal subjects the right ventricle contracted on average 7 ms after the left, and the last region to contract was the right ventricular outflow tract. In 15 subjects with left bundle branch block the left ventricle contracted 69 ms after the right, contraction spreading from the septum to the lateral wall. In 12 subjects with right bundle branch block right ventricular contraction occurred 54 ms after the left. In 11 subjects with right bundle branch block and left anterior fascicular block both right and left ventricular contraction were delayed, the right more so than the left. In three of five subjects with the Wolff-Parkinson-White syndrome and four with frequent ventricular extrasystoles areas of early contraction corresponded to areas of early depolarisation. It is concluded that ventricular contraction can be studied non-invasively and follows a pattern to be expected from the pattern of electrical depolarisation.

Cardiac Complexes, Premature↗
PubMed2001

Breakthrough of 225Ac and its radionuclide daughters from an 225Ac/213Bi generator: development of new methods, quantitative characterization, and implications for clinical use.

Bisumth-213, a short-lived alpha particle emitting radionuclide, is generated from the decay of 225Ac, which has a half-life of 10 days. The development of a clinical 225Ac/213Bi generator and the preparation of a 213Bi radiolabeled antibody for radioimmunotherapy of leukemia have been reported. The 225Ac decay scheme is complex; therefore a thorough understanding of the impact of both the parent 225Ac and its daughters on radiolabeling, purification, and quantification is necessary for optimal use of the generator system. This paper reports: (i) unique new methods to measure 221Fr, 213Bi, and 209Pb, the prominent daughters of 225Ac; and (ii) a quantitative evaluation of 225Ac/213Bi generator breakthrough and the radionuclidic purity of 213Bi labeled radiopharmaceutical dose formulations. A quantitative multi-dimensional proportional scanning method was employed to distinguish and measure specific daughter radionuclides. This method combines thin layer chromatography in two perpendicular directions with attenuated collimation as a function of time for data collection and analysis. Francium-221 and 213Bi eluted differentially from the generator, and 221Fr contributed minimally to unchelated 213Bi in the reaction and final products. Lead-209 was present in the reaction solution, but not strongly bound by the chelating moiety either (i) under the 213Bi labeling reaction conditions or (ii) following chelated 213Bi decay. As a consequence of incorporating several new procedures to the operation of the generator, 225Ac breakthrough in the final product was further reduced and represented a trivial contaminant in the final drug formulations.

Actinium↗
PubMed1990

Production of radionuclides for medicine.

Naturally occurring, nuclear reactor-produced, cyclotron-produced, and generator-produced radionuclides are reviewed with special reference to nuclear medical and biological use. General methods of labeling, and 99mTc, 131I, 125I, 123I, 11C, 13N, 15O, 3H, and 14C labeling methods are described.

Isotope Labeling↗