Experience on the production of Pakgen 99Mo-99mTc generators

A facility for the production of 99Mo-99mTc generators (GPL) in clean room system was provided by the IAEA under Technical Cooperation Project. Regular production of Pakgen 99mTc generators has been started from January 2003. The GPL is provided with A, C and D categories of clean room specifications and various materials used for generator preparation are transferred through airlocks while dress change rooms are provided for personnel. More than 1800 Pakgen 99mTc generators with calibrated activities (five days reference date) ranging from 300 to 600 mCi of 99Mo have been supplied to various nuclear medical centres in Pakistan. Before preparation, the generator bodies and various sections of GPL have been cleaned and disinfected. During the preparation, required calculated activity of 99Mo has been loaded on the columns of pre assembled generators by prewash, loading and postwash steps and quality of the generator has been checked by elution efficiency and molybdenum breakthrough of eluate obtained after an hour from postwash step by comparing the measured activity with the theoretical activities. All these calculations have been carried out using computer programme MOGEN-I developed in Visual Basic 6 software; this software is suitable for recording and acquitting commercial data, monitoring production and quality control. Mathematical equations for theoretical calculation of generator parameters using 99Mo-99mTc-99Tc decay schemes have been used in this software; otherwise these calculations are laborious and time consuming. During the elution, theoretical prediction of the performance of a 99Mo-99mTc generator, in terms of the activity of 99Mo, 99mTc on the column, activity of 99mTc in the generator eluate, the generator elution efficiency and the total mass of technetium (99mTc + 99Tc ) present in a given eluate, have been carried using another software MOGEN-II. The input variables are 99Mo activity, generator elution efficiency, number of elutions, the growth time between elutions, the decay time between elution and the use of 99mTc. The output of the program for each elution gives the activities of 99Mo and 99mTc, atom numbers of 99Mo, 99mTc and 99Tc and the 99Tc/99mTc atom ratio for the generator immediately before elution, for fresh eluate, for decayed eluate and for the generator after elution. This software will be useful for judging the quality of Pakgen 99mTc generators for a week or so. Pakgen 99mTc generator provides, by elution, 99mTc-sodium pertechnetate in sterile, isotonic solution ready for intravenous or oral administration or for aseptic preparation of 99mTc labelled radiopharmaceuticals. All Pakgen 99mTc generators are test eluted before shipment. Quality tests performed are elution efficiency, molybdenum breakthrough, radiochemical purity, chemical purity, radionuclidic purity, sterility and apyrogenicity. The eluate fulfils the quality control criteria prescribed by International Atomic Energy Agency and various Pharmacopoeias like United States, British and European for sodium pertechnetate 99mTc injection. In hospitals, the Pakgen 99mTc generators showed optimum performance in terms of elution yields, molybdenum breakthrough, labelling yields and quality of gamma scans