COMPARISONS OF 99Mo BREAK THROUGH LEVELS IN 99Mo/99MTC GENERATOR ELUATES FROM TWO MANUFACTURERS AND ITS PURIFICATION FOR NUCLEAR MEDICINE IMAGING.

Abstract

OBJECTIVES: The molybdenum breakthrough assay is a common quality control test carried out to the check contamination due to 99Mo in the 99mTc eluates from 99Mo/99mTc generators. The regulatory authority recommends a limit of 0.15KBq 99Mo/MBq of 99mTc. The licensees are required to comply with it. The present work describes the comparison of the molybdenum breakthrough levels in generators from two different manufacturers and purification of the eluates with elevated levels of molybdenum breakthrough before its application in nuclear medicine imaging procedures. METHODS: The Molybdenum breakthrough assay was performed by canister method with activity meter which is a semiautomatic system that displays result after performing steps in series. The step involved background estimation, 99Mo activity determination in canister and 99mTc radioactivity assay without canister. RESULTS: It was observed that 5 % of indigenously manufactured 99Mo/99mTc generators had elevated levels of molybdenum breakthrough whereas all the imported generators had molybdenum breakthrough within permissible levels. The 99mTc eluates showing higher levels of 99Mo were purified before using it for routine radiolabelling. It was observed that in the purification process on the average 26% of initial 99mTc radioactivity was lost. CONCLUSIONS: The purification method employed enabled the department to continue the routine imaging services besides revenue generation and use of available resources which otherwise could not be utilized due to regulatory constraints.

Keywords: Nuclear Medicine; Quality control; Molybdenum Breakthrough; Regulatory limit.