assessment of molybdenum breakthrough levels in molybdenum-99/technetium-99m generators: one year experience at nimra jamshoro pakistan

background: technetium-99m radioisotope is the backbone of any nuclear medicine institute. this radioisotope is acquired by the elution of molybdenum-99/technetium-99m generator which emits 141 kev gamma ray and having 6.04 hour half-life. occasionally the contents of molybdenum-99 may mix up with elute, which may affect image quality and patients may receive higher doses than recommended. this study was initiated to check and evaluate the contamination of molybdenum-99 in molybdenum-99/technetium-99m generators used at nuclear institute of medicine and radiotherapy (nimra) jamshoro pakistan before its administration to patients for diagnostic procedures. materials and methods: the molybdenum-99 impurity in technetium-99m elute for 50 generators was studied during the year 2012. the measurements were made using dose calibrator and a standard canister at the time of first elution of the generators. the dose calibrator displays result after executing various steps in a sequence. due to some production process error or any mechanical fault high activity of molybdenum-99 was recorded and removed with decrease in technetium-99m yield. results: the most of eluted generators (90%) contained 10% of molybdenum breakthrough of the permissible limit (p < 0.05). the high activity of molybdenum-99 was recorded in only 6% of the generator and removed by using standard methods with some reduced technetium-99m activity. conclusion: the molybdenum breakthrough was according to recommended standards in most of the generators. the removal of high contents of molybdenum-99 enabled the institute to continue routine imaging services by improved image quality and reduction in radiation dose to the patients.