Technetium-99m (Tc-99m) pertechnetate (TcO4) imaging with cyclotron produced Tc-99m compared with generator Tc-99m

Objectives With the impending closures of the reactors in Petten and Chalk River there is a need to validate alternative sources of Tc-99m for routine clinical imaging. We have developed a GMP and GCP clinical trial to compare TcO4 produced by cyclotron (cpert) with TcO4 produced from a generator (pert) to evaluate the clinical potential of this production method replacing reactor supply.

Methods Cpert was obtained via proton irradiation of 99.27% enriched 100Mo metal powder pressed into an aluminum target plate. The 100Mo target was dissolved (30% H2O2, 60°C) and neutralized (3M (NH4)2CO3) prior to aqueous biphasic extraction chromatographic (ABEC) separation [1] and strong cation exchange (SCX) purification. Aluminum ion breakthrough , pH, and radiochemical purity) via instant thin layer chromatography (ITLC) of the recovered pertechnetate were evaluated. The extracted cpert demonstrated <2.5μg/mL aluminum ion concentration, a pH in the range of 5.0-7.0, and RHT that was typically less than 1-2% 24 hours post-extraction. Recovery times were <30 minutes from end-of-bombardment to the SCX-purified pertechnetate solution. Gpert was obtained from the central radio pharmacy. Whole body Tco4 imaging was performed using modified SNM procedure guidelines for Meckels diverticulum in 10 cpert and 20 case controlled gpert patients post thyroidectomy. Qualitative and quantitative comparisons of biodistribution were obtained by 2 blinded nm physicians.

Results No hematological or biochemical toxicity was associated with the cpert injections. Qualitative and quantitative analysis showed identical biodistribution with no features allowing differentiation of the 2 tracers. Case control comparison showed that uptake, clearance and biodistribution were identical for cpert and pert.

Conclusions Cpert is a clinically valid substitute for gpert in routine clinical imaging and offers a future route of Tco4 supply.

Research Support NRCan NISP gran