Altered [Tc]Tc-MDP biodistribution from neutron activation sourced Mo.

Given potential worldwide shortages of fission sourced Mo/Tc medical isotopes there is increasing interest in alternate production strategies. A neutron activated Mo source was utilized in a single center phase III open label study comparing Tc, as Tc Methylene Diphosphonate ([Tc]Tc-MDP), obtained from solvent generator separation of neutron activation produced Mo, versus nuclear reactor produced Mo (e.g., fission sourced) in oncology patients for which an [Tc]Tc-MDP bone scan would normally have been indicated. Despite the investigational [Tc]Tc-MDP passing all standard, and above standard of care, quality assurance tests, which would normally be sufficient to allow human administration, there was altered biodistribution which could lead to erroneous clinical interpretation. The cause of the altered biodistribution remains unknown and requires further research.