The continuing important role of radionuclide generator systems for nuclear medicine

Abstract

In this review, the continuing importance and status of development of radionuclide generator systems for nuclear medicine are discussed. Radioisotope costs and availability are two important factors, and both nuclear reactors and accelerator facilities are required for production of the parent radioisotopes. Radionuclide generator research is currently focused on the development of generators which provide radioisotopes for positron emission tomography (PET) applications and daughter radioisotopes for various therapeutic applications which decay primarily by particle emission. Generator research continues to be influenced by developments and requirements of complementary technologies, such as the increasing availability of PET. In addition, the availability of a wide spectrum of tumor-specific antibodies, fragments, and peptides for radioimmunodiagnosis and radioimmunotherapy has stimulated the need for generator-derived radioisotopes. The advantages of treatment of arthritis of the synovial joints with radioactive particles (radiation synovectomy) may be expected to be of increasing importance as the elderly population increases, and many of these agents are prepared using generator-derived radioisotopes such as yttrium-90 and rhenium-188. Therapeutic use of the "in vivo generator" is a new approach, where the less radiotoxic parent radioisotope is used to prepare tissue-specific therapeutic agents. Following in vivo site localization, decay of the parent provides the daughter for therapy at the target site. The principal foundation of most diagnostic agents will continue to require technetium-99m from the molybdenum-99/technetium-99m ("Moly") generator. With the limited availability of nuclear reactors and facilities necessary for production and processing of fission 99mTc and the significant issues and problems associated with radioactive waste processing, however, the possibility of utilizing lower specific activity 99Mo produced from neutron activation of enriched 98Mo may become practical in the future.

188Re or 90Y‐labelled anti‐CD66 antibody as part of a dose‐reduced conditioning regimen for patients with acute leukaemia or myelodysplastic syndrome over the age of 55: results of a phase I–II study

“…The generator was supplied by the Oak Ridge National Laboratory (Oak Ridge, TN, USA). Full details of generator performance have been published elsewhere (Knapp & Mirzadeh, 1994). The labelling procedure for the antibody has been previously described in detail (Seitz et al, 1999).…”

How Far Are We from Dose On Demand of Short-Lived Radiopharmaceuticals?

“…Generators of radioactive raw nuclides have been widely used (e.g., 99m Tc, 68 Ga) [6]; the elution of the desired radionuclide is generally done upon demand and followed by simple chemical reactions (generally performed directly in the same NM department) to obtain the final radiopharmaceutical. This approach respects the Restarting requirement, though limited to the raw nuclide production and not to the pharmaceutical preparation; however, it generally does not respect the Discretization nor the Reduction requirements, as it is difficult to separately handle the amount of chemicals needed for a single patient (i.e., in the μLs range).…”

Successful Labeling of99mTc-MDP Using99mTc Separated from99Mo Produced by100Mo(n,2n)99Mo

“…1) Namely, 99m Tc has a short halflife of 6 h and decays to the ground state ( 99g Tc) by emitting the monochromatic 141 keV -ray. These nuclear properties of 99m Tc allow the reduction in radiation dose in the patient while providing accurate position information on the tissue or organ of interest.…”