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

INTRODUCTION

Production of Mo/Tc using an electron linear accelerator (linac) and activated carbon (AC)-based Tc generator (linac-AC) is an alternative approach to the conventional fission production of Mo/Tc. As a preliminary investigation of the clinical applicability of a linac-AC-derived Tc radiopharmaceutical, the biodistribution of linac-AC-derived [Tc]sodium pertechnetate ([Tc]NaTcO) was measured and compared against fission-derived [Tc]NaTcO at one time point.

METHODS

Mo was produced by irradiating nonenriched MoO targets with bremsstrahlung photons generated from 55.5-MeV linac electron beams. Tc was then separated and purified from the Mo using an AC-based Tc generator. Subsequently, biodistribution of the linac-AC-derived [Tc]NaTcO in healthy female Slc:ICR mice (n = 6) was measured by dissection and compared with that of fission-derived [Tc]NaTcO (n = 4) at 30 min after injection.

RESULTS

The two types of [Tc]NaTcO exhibited similar biodistribution in all the organs and tissues examined: the uptakes of [Tc]NaTcO 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 [Tc]NaTcO.

CONCLUSION

The clinical applicability of linac-AC-derived [Tc]NaTcO was suggested by its similar biodistribution with fission-derived [Tc]NaTcO at one time point. Further biodistribution studies at multiple time points are encouraged to demonstrate the bioequivalence between linac-AC- and fission-derived [Tc]NaTcO.