Production, processing and small animal PET imaging of titanium-45

Titanium-45 was prepared as a tool for elucidation of the mechanism of action of titanium anticancer drugs in vivo using microPET imaging. Titanium-45 was produced by the ⁴⁵Sc(p,n)⁴⁵Ti nuclear reaction using 14.5 MeV protons. Sufficient yields of ⁴⁵Ti were produced and separated from the target material with 99.8% radionuclidic purity using a simple, efficient separation procedure. A typical bombardment of 5 μA for 1 h produced an average of 2105±150 MBq (56.9±4.0 mCi) at the end of bombardment (EOB), well within acceptable range of the calculated theoretical yields of 2165 MBq and 433 MBq μA^-1 h^-1 (58.5 mCi and 11.7 mCi μA^-1 h^-1). This amount of activity is sufficient for the radiosynthesis of target compounds as well as imaging studies. MicroPET images of a miniature Derenzo phantom show excellent resolution where rods of 1.25 mm were separated by four times their diameter. Titanium-45 can be easily produced on a biomedical cyclotron with excellent yields as compared to calculated theoretical values with imaging studies demonstrating that the decay properties of titanium-45 are well suited for microPET.