Kurt R. Zinn

Production of no‐carrier‐added 64Cu from zinc metal irradiated under boron shielding

Background. Positron emission tomography offers advantages for radioimmunodiagnosis of cancer but requires radionuclides of appropriate half‐life that have high specific activity and high radio‐purity. This work was designed to develop a viable method to produce and purify 64Cu, which has high specific activity, for positron emission tomography.

Investigation of the appearance of supplemental enriched Se-76 using the human nail as a dietary monitor

The principal objective of this study was to determine if the use of a stable enriched tracer of Se-76 could be used to determine the delay time between a dietary intake of selenium and its appearance in fingernails and toenails. Selenium is an essential trace element in human nutrition. It has been studied at the Missouri University Research Reactor (MURR) for the past 15 years using an Instrumental Neutron Activation Analysis (INAA) technique. The principal route of human exposure to selenium is through the diet. Selenium concentrations of nails, blood, hair, and urine have been used as indicators of dietary selenium intake. In this study, a cohort consisting of seven men and five women ingested three selenium supplements of 150 μg each over a three day period. The selenium was enriched in Se-76 (96.48%) and ingested as selenite in orange juice following an overnight fast. Fingernails and toenails were collected prior to the selenium supplementation and for several months afterward to be used as biochemical indicators. The peak76Se concentration in the fingernails and toenails occurred at 19–23 and 16–32 weeks after supplementation, respectively.

Human monoclonal antibody developed against ovarian cancer cell surface antigen

Background. Murine monoclonal antibodies (MoAb) potentially can be used in the radioimmunodetection and radioimmunotherapy of cancer. However, the administration of these radiopharmaceuticals to humans often leads to induction of human anti‐murine antibodies (HAMA). HAMA has many disadvantages, which could decrease efficacy of the murine MoAb. The purpose of this work was to produce human monoclonal antibody against a human ovarian cancer cell surface antigen (OCCSA), which was not present in normal ovarian cells. This 200‐kilodalton OCCSA also was used in the present study for characterizing the human monoclonal antibody.

186Re/188Re labeled polypeptide microspheres as a potential radiation synovectomy agent

Polypeptide microspheres containing polycysteine crosslinked with polylysine were prepared and radiolabeled with186Re and188Re. High labeling yields with the microspheres with both186Re and188Re (97%) were obtained, and above 99% retention of radiolabels in water in 24 hours was obtained. Rhenum-186 labeled polycysteine and polylysine microspheres (1∶1 ratio, 20 μm as mean diameter) were injected intra-articularly into the rear stifes (knee joints) of normal New Zealand white rabbits. About 87% of injected dose was retained in rabbit stifles and adjacent tissues in 96 hours after injection, while most of the activity lost from the joints was excreted in the urine. Due to its simplicity of preparation and radiolabeling, versatility, and biodegradability, this type of conjugate system may become the therapeutics of choice for radiation synovectomy.

Radioisotope Generators for Nuclear Medicine Based on Fajans Adsorption on Glass Microspheres

Several radioisotope generator systems exist in which the carrier-free daughter product would precipitate if present in macro amounts at pH levels at which the parent is soluble. Included among these are the {sup 68}Ge/{sup 68}Ga, {sup 90}Sr/{sup 90}Y, and {sup 47}Ca/{sup 47}Sc pairs. This paper reveals that in these systems, chemical separation can be achieved by Fajans adsorption of the radiocolloidal daughter products onto surfaces such as activated glass microspheres at an appropriate pH. This is followed by washing to remove the parent solution and desorption of the daughter crop by acid washes. Investigation of the Ge/Ga and Sr/Y systems demonstrated that this solid-phase extraction method is erratic, but can give daughter yields as high at 89% with separation factors up to {approximately} 10,000 form parent isotope. This method has the potential for producing daughter isotopes with a minimum of metal and organic impurities for labeling cells, receptor binding ligands, and antibodies for diagnostic and radiotherapeutic purposes.

Detection of ovarian cancer by 198Au-labeled human monoclonal antibody

Background. There is no reliable method for the early diagnosis of ovarian cancer. Radiolabeled monoclonal antibodies have potential to assist in early diagnosis, but they are limited by problems that include antibody specificity, stability, and immunoreactivity, as well as patient reactions to the antibodies used.

The development of a rectilinear scanner utilizing high resolution gamma-ray detection

A rectilinear scanner has been constructed which incorporates high resolution gamma-ray spectroscopy. This scanner was built to simultaneously image the distributions of multiple gamma-emitting radionuclides in small animals, such as rabbits and rats. The instrument design is described, followed by studies of the Ge(Li) detector response and calibration tests of a single straight-hole collimator. Based on these results, two new collimators were designed and constructed; (1) a six tapered-hole focusing collimator and (2) a nine straight-hole focusing collimator. These new collimators are advantageous because they offer an increased efficiency of gamma-ray detection during scanning. They also give better image resolution in the differentiation of two points (or organs) on a plane. The results of the calibration tests and comparisons of the resolution and efficiency among collimators are illustrated and discussed.