Decay data and production yields of some non-standard positron emitters used in PET.

The increasing significance of non-standard positron emission tomography (PET) nuclides in medicine is briefly outlined. The decay data of those radionuclides are generally well known, except for the positron emission intensity (Ibeta+) in a few cases. The recent precise measurements on the Ibeta+ values for (64)Cu, (76)Br, (120)I and (124)I are described. Some general aspects of cyclotron production of radionuclides are discussed. The need of some fundamental nuclear chemistry research with regard to the development of a new production route is demonstrated. An accurate knowledge of the excitation function of a nuclear reaction is essential to optimize the production route. The yield of a product calculated from the excitation function of a reaction gives the maximum achievable yield. Such yields are given for 24 radionuclides presently attracting attention. The experimental yields are always lower than the theoretical values, calling upon constant improvements in targetry and chemical processing procedures. Many of the non-standard PET nuclides, like (64)Cu, (86)Y, (94m)Tc, (124)I, etc. are produced in good yields at low energy cyclotrons while for production of some other radionuclides (e.g. 52Fe, 73Se, 83Sr, etc.) an intermediate energy cyclotron is required.