A preliminary biodistribution study of [99mTc]sodium pertechnetate prepared from an electron linear accelerator and activated carbon-based 99mTc generator

Introduction: Production of Mo-99/(99)mTc using an electron linear accelerator (linac) and activated carbon (AC)-based 99mTc generator (linac-AC) is an alternative approach to the conventional fission production of Mo-99/(99)mTc. As a preliminary investigation of the clinical applicability of a linac-AC-derived (99)mTc radiopharmaceutical, the biodistribution of linac-AC-derived [(99)mTc]sodium pertechnetate ([(99)mTc]NaTcO4) was measured and compared against fission-derived [(99)mTc]NaTcO4 at one time point. Methods: 99Mo was produced by irradiating nonenriched MoO3 targets with bremsstrahlung photons generated from 55.5-MeV linac electron beams. (99)mTc was then separated and purified from the 99Mo using an AC-based (99)mTc generator. Subsequently, biodistribution of the linac-AC-derived [(99)mTc]NaTcO4 in healthy female Slc:ICR mice (n = 6) was measured by dissection and compared with that of fission-derived [(99)mTc]NaTcO4 (n = 4) at 30 min after injection. Results: The two types of [(99)mTc]NaTcO4 exhibited similar biodistribution in all the organs and tissues examined: the uptakes of [(99)mTc]NaTcO4 prepared from the linac-AC method and those prepared from the fission method were 138.9 +/- 69.9%ID/g and 160.6 +/- 49.2%ID/g in the thyroids, respectively, 33.4 +/- 5.5%ID/g and 29.4 +/- 9.1%ID/g in the salivary glands, respectively, and less than 10%ID/g in blood and all the other organs. No adverse effects were observed in the mice administered with either [(99)mTc]NaTcO4. Conclusion: The clinical applicability of linac-AC-derived [(99)mTc]NaTcO4 was suggested by its similar biodistribution with fission-derived [(99)mTc]NaTcO4 at one time point. Further biodistribution studies at multiple time points are encouraged to demonstrate the bioequivalence between linac-AC-and fission-derived [(99)mTc]NaTcO4. (C) 2022 Elsevier Inc. All rights reserved.