Nuclear Medicine Program progress report for quarter ending June 30, 1992

In this report the results of preliminary studies of pancreatic exocrine function in normal patients and volunteers by a simple urine analysis using a new iodine-131-labeled triglyceride are described. The new ORNL agent, 1,2-dipalmitoyl-3-((15-piodophenyl)pentadecan-l-oyl)-rac-glycerol (1,2-Pal-3-IPPA) was radiolabeled with iodine-131 and used in clinical studies in a collaborative program with the Clinic for Nuclear Medicine at the University of Bonn, Germany. The observed rapid urinary excretion of high levels of the orally administered test agent from patients corroborated results from initial studies conducted in laboratory animals (ORNL/TM-12110). In the initial group of normal volunteers and 11 patients with normal pancreatic function an average of 76 {plus_minus} 13.8% of the administered activity was excreted in the urine in 24 h. Studies will now also focus on evaluation of this agent in patients with pancreatic insufficiency. The reactor production of dysprosium-166 in the ORNL High Flux Isotope Reactor (HFIR) and the separation of carrier-free holmium-166 have also been pursued. Holmium-166 (t{sub {1/2}}226.4 h) decays with the emission of high energy beta particles and abundant secondary electrons and is thus of interest for various therapeutic applications. Four-day irradiation of {sup 165}Ho in the HFIR resulted in production of {sup 166}Ho with a specific activitymore » of 7.25 mCi/mg. The formation of {sup 166}Ho by beta-decay of reactor-produced {sup 166}Dy was also evaluated. The specific activity of {sup 166}Dy for an 8-day HFIR irradiation was 3.5 mCi/mg. Preliminary results indicate that carrier-free {sup 166}Ho can be separated from the neutron-irradiated target by HNO{sub 3} elution from di-(2-ethylhexyl)phosphoric acid (HDEHP) impregnated glass beads.« less