Production of Tungsten-188 and Osmium-194 in a Nuclear Reactor for New Clinical Generators

Abstract

Rhenium-l8S and indium-194 ;ire potential candidates Lor radioimmunotherapy with monoclonal antibodies directed against tumor-associiued antigens. Both nuclei are short-lived and decay by high energy B' emission. In addition, both nuclei emit y-rays with energy suitable for imaging. Os reaction and discuss the feasibility of producing sufficient quantities of l94 Os.

188W/188Re Generator System and Its Therapeutic Applications

“…Tungsten-188 is a key example where very high thermal neutron flux is required for production of sufficient specific activity for practical use for the adsorption-based 188 W/ 188 Re generator [4,[9][10][11][12][13][14]. Because of the double neutron capture reaction step, modest thermal cross-section values (Table 1), and product burn-up, the 188 W is reactor produced with relatively low specific activity [11].…”

“…Because of the double neutron capture reaction step, modest thermal cross-section values (Table 1), and product burn-up, the 188 W is reactor produced with relatively low specific activity [11]. For example, 24 d irradiation even at high thermal flux level of Φ th > 10 15 cm −2 s −1 yields 188 W with a specific activity of only 148-185 GBq/g [9]. Use of this relatively low specific activity 188 W requires larger amounts of alumina for the generator column, thus increasing the eluent volume and decreasing the 188 Re concentration (activity/volume (MBq/mL)) [4,5].…”

“…At the Oak Ridge National Laboratory (ORNL, Oak Ridge, Tennessee, USA), the high flux isotope reactor (HFIR), production of 188 W from both 186 W-enriched metal and oxide tungsten targets, has been evaluated over the past several years [4,[8][9][10][11]. Tungsten-188 having adequate specific activity suitable for the production of 188 W/ 188 Re generators can be accomplished also in only a limited number of the research reactors, that is, SM Reactor, RIAR, Dimitrovgrad, Russian Federation, and BR2 Reactor, Belgium.…”

“…Although the total 188 W activity produced per target is higher with the pressed targets, since significantly more target material can be used per target holder, the 188 W specific activity decreases as the mass of the enriched 186 W increases. Although the key factors leading to such a discrepancy are still not well understood, the specific activity of the irradiated 186 W-enriched pellets is considerably less (20-25%) than the specific activity of the irradiated granular/powder enriched 186 W target [9]. Figure 2: ORNL postirradiation processing scheme for pressed/ sintered enriched 186 W metal targets [16].…”

Rhenium-188 Production in Hospitals, by W-188/Re-188 Generator, for Easy Use in Radionuclide Therapy

“…For this reason, a very high neutron flux greater than 8–10 × 10 14  n/cm 2 /s is required for the production of tungsten-188. There are five reactors in the world (the High Flux Isotope Reactor in Oak Ridge National Laboratory, the High Flux Beam Reactor in Brookhaven National Laboratory, the Missouri University Research Reactor, the Fast Flux Test Facility in Westinghouse Hanford and the Japan Materials Testing Reactor), providing such high neutron fluxes and irradiation times varying to 24 hours and 60 days (see [2, Table 1] and [3]). The processing of tungsten-188 is generally conducted in a quartz glass vessel.…”