High specific activity is also required for isotopes meant to be used for labeling hormones and other biological substances for radioimmunoassays and other related assay procedures. Many imaging and therapeutic applications are dependent on the use of concentrated solution of radionuclides. Concentrated solutions of radionuclide provide good labeling yield of molecules. With the passage of time, the eluates obtained from radionuclide generator systems yield low concentration of radionuclides, hence concentration techniques will enhance the working life of radionuclide generators. In this regard the concentration technique developed in this study for Ga-68 will certainly increase the purity of radionuclide as well as ensure the optimum use of generator system in their working life time.

Technetium-99m is mostly eluted from 99Mo/99mTc generator system in all nuclear medicine departments where radiopharmaceuticals are prepared for gamma imaging purposes. The clinically useful lifetime of a fission based 99Mo/99mTc generator is 2 weeks. At the end of first working week, the radioactive concentration of the eluate is about a quarter of that at the beginning of the week that places limitations on the clinical procedures. These include 99mTc-sestamibi for myocardial perfusion studies and 99mTc-ECD forbrain imaging. Hence safe procedure is needed for the concentration of pertechnetate obtained from column chromatography generators. The concentrated solution of pertechnetate obtained by these methods were successfully employed for labeling of MIBI and ECD kits.