nSPECT: A Radioisotope-Free Approach to Nuclear Medicine Imaging

The imminent closure of NRU reactor in Canada and HFR reactor in Holland threatens ~ 70% of the world´s supply of ^99mTc used in over 30 million medical applications yearly. Researchers around the globe are investigating alternative methods of production, mainly using accelerators. This paper presents a concept feasibility study of a novel technique dubbed nSPECT, in which non-radioactive isotopes administered to patients would be activated with slow neutrons to emit prompt gamma rays (PGNA). Although a common technique of elemental analysis, PGNA has not been used for medical imaging. This paper presents SPECT images of ¹³¹I at activity levels that could be reasonably produced by neutron activation of ¹⁴⁹Sm in vivo. Simulated Compton noise from hydrogen was added to degrade the images to levels that would be expected in practice. Advantages of nSPECT are discussed. This concept feasibility study suggests that nSPECT might provide an alternative means for medical imaging should the accelerator-based methods fail to make sufficient quantities of ^99mTc.