Clinical Efficacy Of Sodium [Tc-99m] Pertechnetate From Low Specific Activity Mo-99/Tc-99m Autosolex Generator In Hospital Radiopharmacy Center

BACKGROUND: Production of Tc-99m from low specific activity (LSA) Mo-99 obtained from Mo-98(n,gamma)Mo-99 reaction in research reactor and Mo-100(gamma,n)Mo-99 reaction in accelerator or directly from Mo-100(p,2n)Tc-99m nuclear reaction in cyclotron, has been explored [1]. The methyl ethyl ketone (MEK) based solvent extraction technique is a well-known method for the separation of Tc-99m from low specific activity Mo-99. The Mo-99/(99)mTc autosolex generator [2], a computer controlled automated module, utilizes the conventional MEK solvent extraction method for extraction of Tc-99m. Herein, we have validated the usage of autosolex by preparing quite a large number of pharmacopoeia grade (TcO4-)-Tc-99m (No. of batches: 97) using 7.40-27.5 GBq of LSA Mo-99-Sodium Molybdate ((MoO42-)-Mo-99) solution (No. of batches: 31). To check the efficacy of (99)mTcO(4)(-) towards radiolabeling, a wide range of (99)mTc-radiopharmaceuticals ((99)mTc-RPs) including fourth generation (99)mTc-radiopharmaceuticals has been evaluated. Finally, the clinical efficacy of these Tc-99m-RPs has been evaluated. To make the autosolex generator more versatile, we have studied further some of the important issues relevant to autosolex generator viz. the functionality of conductivity detector with respect to the concentration of sodium hydroxide, purity of reagents/materials used and radiation dose outside the module.MATERIAL AND METHODS: The (TcO4-)-Tc-99m was extracted from the autosolex as described in the reported literature [2] using 7.40-27.5 GBq of LSA (MoO42-)-Mo-99. The (99)mTc radiopharmaceuticals prepared from cold kits (Tc-99m-cold kits), obtained from our center, using standard procedures [3], subjected to required QC as per Indian Pharmacopeia monograph [4] and used in scintigraphic imaging in patients. The radiation exposure dose to the operator was compared between autosolex and manual MEK based solvent extraction generator.RESULTS: The extracted (99)mTcO(4)(-) from autosolex is a clear and colorless solution with pH between 5.0 and 6.5. The elemental molybdenum (Mo) and aluminum (Al) content < 10 mu g/mL, MEK levels < 0.1%, Mo-99 breakthrough < 0.026% and radiochemical purity (RCP) > 98%. All the extracted (TcO4-)-Tc-99m batches complies sterility test, endotoxin limit (EL) < 5 EU/mL. The RCP of all the labeled (99)mTc-RPs > 95%. The autosolex delivers much less radiation dose to the operator than the convention manually handled MEK based solvent extraction generator.CONCLUSIONS: Autosolex Generator was successfully validated to obtain pharmaceutical grade (99)mTcO(4)(-) using LSA (MoO42)-Mo-99 up to a higher range of activity of 27.5 GBq and the generator is safe in radiological and pharmacological point of view. The work also confirms the suitability for the preparation of various types of Tc-99m-RPs, especially using fourth generation Tc-99m-RPs using autosolex generator and using these Tc-99m-RPs for scintigraphic imaging in patients.