Introduction: Production of 99 Mo/ 99m Tc using an electron linear accelerator (linac) and activated carbon (AC)-based 99m Tc generator (linac-AC) is an alternative approach to the conventional fission production of 99 Mo/ 99m Tc. As a preliminary investigation of the clinical applicability of a linac-AC-derived 99m Tc radiopharmaceutical, the biodistribution of linac-AC-derived [ 99m Tc]sodium pertechnetate ([ 99m Tc]NaTcO 4 ) was measured and compared against fission-derived [ 99m Tc]NaTcO 4 at one time point.
Methods: 99 Mo was produced by irradiating nonenriched MoO 3 targets with bremsstrahlung photons generated from 55.5-MeV linac electron beams. 99m Tc was then separated and purified from the 99 Mo using an AC-based 99m Tc generator. Subsequently, biodistribution of the linac-AC-derived [ 99m Tc]NaTcO 4 in healthy female Slc:ICR mice (n = 6) was measured by dissection and compared with that of fission-derived [ 99m Tc]NaTcO 4 (n = 4) at 30 min after injection.
Results: The two types of [ 99m Tc]NaTcO 4 exhibited similar biodistribution in all the organs and tissues examined: the uptakes of [ 99m Tc]NaTcO 4 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 [ 99m Tc]NaTcO 4 .
Conclusion: The clinical applicability of linac-AC-derived [ 99m Tc]NaTcO 4 was suggested by its similar biodistribution with fission-derived [ 99m Tc]NaTcO 4 at one time point. Further biodistribution studies at multiple time points are encouraged to demonstrate the bioequivalence between linac-AC- and fission-derived [ 99m Tc]NaTcO 4 .
(Copyright © 2022 Elsevier Inc. All rights reserved.)