“…The gamma-emitting radionuclide 99m Tc and its Group VII congener 186/188 Re have found wide-ranging applications in radiodiagnosis [1][2][3][4][5][6] and radiotherapy [7,8], respectively. The optimal nuclear properties of 99m Tc (γ-emitter, E max = 140 keV, t 1/2 = 6 h), as well as its convenient availability from 99 Mo/ 99m Tc generator system [9], have made 99m Tc radiopharmaceuticals virtually ideal for imaging low capacity high density receptors by deploying SPECT (single photon emission computerized tomography), while both isotopes 186 Re (t 1/2 = 90.64 h, E max = 1.1 MeV) and 188 Re (t 1/2 = 17 h, E max = 2.1 MeV) are suitable for therapeutic use b y means of β-irradiation.…”