⁹⁵ᵍTc and ⁹⁶ᵍTc as alternatives to medical radioisotope ⁹⁹ᵐTc

Abstract

We studied ⁹⁵ᵍTc and ⁹⁶ᵍTc as alternatives to medical radioisotope ⁹⁹ᵐTc. ⁹⁶ᵍTc(⁹⁵ᵍTc) can be produced by (p, n) reactions on an enriched ⁹⁶Mo (⁹⁵Mo) target with a proton beam provided by a compact accelerator such as a medical cyclotron that generate radioisotopes for positron emission tomography (PET). The γ-rays are measured with an electron-tracking Compton camera (ETCC). We calculated the relative intensities of the γ-rays from ⁹⁵ᵍTc and ⁹⁶ᵍTc. The calculated γ-ray intensity of a ⁹⁶ᵍTc(⁹⁵ᵍTc) nucleus is as high as 63% (70%) of that of a ⁹⁹ᵐTc nucleus. We also calculated the patient radiation doses of ⁹⁵ᵍTc and ⁹⁶ᵍTc, which were larger than that of ⁹⁹ᵐTc by a factor of 2–3 based on the applied assumptions. A medical PET cyclotron which can provide proton beams with energies of 11–12 MeV and a current of 100 μA can produce 12 GBq (39 GBq) of ⁹⁶ᵍTc(⁹⁵ᵍTc) for operation time of 8 h, which can be used for 240 (200) diagnostic scans.