The High Flux Isotope Reactor (
HFIR) at the Oak Ridge National Laboratory (
ORNL) represents an important resource for the production of a wide variety of medical radioisotopes. First beginning operation
in 1965, the high thermal neutron flux (2.5×10
15 neutrons/cm
2/sec at 85 MW) and versatile target irradiation and handling facilities provide the opportunity for production of a wide variety
of neutron-rich medical radioisotopes of current interest for therapy. In addition to serving as a key production site for
californium-252 and other transuranic elements, important examples of therapeutic radioisotopes which are currently routinely
produced in the
HFIR for distribution include dysprosium-166 (parent of holmium-166), rhenium-186, tin-117
m and tungsten-188 (parent of rhenium-188). The nine hydraulic tube (
HT) positions in the central high flux region permit the insertion and removal of targets at any time during the operating cycle
(22–24 days) and have traditionally represented a major site for production of medical radioisotopes. To increase the irradiation
capabilities of the
HFIR, special target holders have recently been designed and fabricated which will be installed in the six Peripheral Target Positions
(
PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and will be
used for long-term irradiations, such as required for the production of tin-117
m and tungsten-188. Each of the
PTP tubes will be capable of housing a maximum of eight
HT targets, thus increasing the total maximum number of
HT targets from the current nine, to a total of 57. In this paper the therapeutic use of reactor-produced radioisotopes for
bone pain palliation and vascular brachytherapy and the therapeutic medical radioisotope production capabilities of the
ORNL HFIR are briefly discussed.