A comparison of rat SPECT images obtained using 99mTc derived from 99Mo produced by an electron accelerator with that from a reactor

Recent shortages of molybdenum-99 (Mo-99) have led to an examination of alternate production methods that could contribute to a more robust supply. An electron accelerator and the photoneutron reaction were used to produce Mo-99 from which technetium-99m (Tc-99m) is extracted. SPECT images of rat anatomy obtained using the accelerator-produced Tc-99m with those obtained using Tc-99m from a commercial generator were compared. Disks of Mo-100 were irradiated with x-rays produced by a 35 MeV electron beam to generate about 1110 MBq (30 mCi) of Mo-99 per disk. After target dissolution, a NorthStar ARSII unit was used to separate the Tc-99m, which was subsequently used to tag pharmaceuticals suitable for cardiac and bone imaging. SPECT images were acquired for three rats and compared to images for the same three rats obtained using Tc-99m from a standard reactor Mo-99 generator. The efficiency of Mo-99-Tc-99m separation was typically greater than 90%. This study demonstrated the delivery of Tc-99m from the end of beam to the end user of approximately 30 h. Images obtained using the heart and bone scanning agents using reactor and linac-produced Tc-99m were comparable. High-power electron accelerators are an attractive option for producing Mo-99 on a national scale.