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.

Dual energy computerized tomography: a simplified approach.

Attenuation numbers of various organic liquids were measured in a phantom at the low and high X-ray beam settings of the Mark I and CT 1010. The readings were translated into absolute units and ratios computed. There is a nonlinear relationship between this ratio and the effective atomic number of the compounds tested. A ratio of one defines a substance with energy dependence like water. Ratios below one definite anhydrous substances composed of elements with low atomic numbers. Ratios greater than one defined substances containing elements with high atomic numbers.

In vivo stability and distribution of [131I]iodomethyl trimethylammonium chloride: concise communication.

[131I]iodomethyl trimethylammonium chloride (I-131 TMA) was prepared by the isotope-exchange reaction of diiodomethane with Na131I, followed by reaction with trimethylamine. A specific activity of 20 microCi/mg was obtained. Tissue distributions following intravenous injection of I-131 TMA in mice showed that between 10 min and 2 hr, the highest accumulations of radioactivity were in the urine, kidney, and heart. The uptake of this compound in the heart was very rapid, and the levels of radioactivity remained fairly high up to 2 hr. At 10, 30, 60, and 120 min the heart-to-blood ratios were, respectively, 10.2, 7.7, 8.3, and 9.6. Thyroid uptake of this compound in the rats and analysis of urine samples of the mouse indicated no extensive deiodination of the compound in vivo. These results show that this compound does have potential for use in myocardial imaging. In addition, its stability in vivo makes it very useful for the radiolabeling of compounds containing quaternary ammonium moieties.

Manganese-52m, a new short-lived, generator-produced radionuclide: a potential tracer for positron tomography.

A new generator system has been developed using the Fe-52 leads to Mn-52m parent-daughter pair. Fe-52, half-life 8.3 hr, is isolated on an anion-exchange column, and Mn-52m is eluted in hydrochloric acid. Breakthrough is less than 0.01% and the yield is 75%. The 21.1-min half life of Mn-52m is ideal for use in sequential studies, but is long enough to permit radiochemical manipulations to control biodistribution. Animal studies indicate that Mn-52m is an ideal nuclide for myocardial imaging, combining rapid blood clearance and high concentration in the myocardium. An added advantage is that Mn-52m decays 98% by positron emission and is useful for positron computer tomography.

Myocardial imaging with 134mCesium. Comparison of scintigraphic and cineradiographic results.

Thirty-four patients had noninvasive myocardial perfusion imaging at rest using 134mCs. The results were compared with the results of coronary cineangiography and left ventriculography. All 21 patients who had abnormal left ventriculograms had corresponding myocardial imaging defects. This group included 14 patients with electrocardiographic evidence of either an old inferior, anteroseptal, anterior, or anterolateral myocardial infarction. Thirteen patients had normal left ventriculograms: this group included 6 patients with 75% or greater obstruction of one or more coronary arteries and 7 patients with normal or insignificantly diseased vessels. Only 2 of these patients had abnormal myocardial images: both had severe obstruction of the proximal left anterior descending artery without collateral filling of this vessel. In the resting patient who has 134mCs myocardial imaging, we concluded that we primarily are visualizing varying degrees of scarred myocardium rather than reversibly ischemic myocardium.

Rectal perchlorate for unconscious patients prior to brain scintigraphy with pertechnetate: concise communication.

Patients undergoing brain scintigraphy with pertechnetate are frequently premedicated with oral perchlorate. However, the oral route is difficult to employ in unconscious or uncooperative patients or when oral intake is restricted. In such situations, rectal administration of sodium perchlorate dissolved in water is an effective alternative to oral administration.

Characterization and growth-depressing activity for chickens of several natural phenolic materials.

Several natural phenolic materials were analyzed for gallic acid and were further characterized for dialyzability and flavonoid content. These materials were added to a diet and fed to broiler strain chicks for 4 weeks. The depression in growth caused by these phenolic materials was compared with that of tannic acid on a gallic acid equivalency basis. The activities relative to tannic acid (congruent to 100) were as follows: methyl gallate, 195; valonia, 117; wattle, 114; allepo tannic acid, 107; eucalyptus, 105, myrobalan, 98; tara crystals, 76; mangrove, 72; quebracho, 39; gallic acid, and ellagic acid, O. It was impossible to clearly relate the growth depressing activity of the materials to hydrolyzability or relative content of smaller phenols.