An automated module for the separation and purification of cyclotron-produced 99mTcO4-.
BACKGROUND
The shortage of reactor-produced molybdenum-99 ((99)Mo, t(½)=66 h) has renewed interest in alternative production methods of its daughter isotope, technetium-99m ((99m)Tc, t(½)=6.02 h). While adsorption chromatography serves as a mechanism for selective elution of sodium pertechnetate from technetium generators, this method of purification is not sufficient for many alternative production methods. Several ion-separation/solid phase extraction chromatography methods are known, yet none have been demonstrated on cyclotron-produced [(99m)Tc]TcO(4)(-). Herein we describe the design, manufacture and optimization of a remotely operated module for the purification of sodium pertechnetate from a bulk solution of molybdate.


METHODS
The automated purification module was designed to separate [(99m)Tc]TcO(4)(-) using either Dowex 1x8 or an Aqueous Biphasic Extraction Chromatography (ABEC) resin. (100)Mo composite targets were irradiated with 18.5 MeV protons for 10 μA·h using an ASCI TR19 cyclotron. Once purified, the radiopharmaceutical quality of (99m)TcO(4)(-) isolated from each process (Dowex and/or ABEC) was established by assaying for molybdate breakthrough, alumina levels and, in the case of the Dowex approach, residual organics.


RESULTS
The separation processes are efficient (75% for Dowex, 90% for ABEC) and complete in less than 30 min. Overall, up to 2.1 GBq of (99m)Tc was produced using the (100)Mo(p,2n)(99m)Tc transformation, processed using the separation module and subjected to a detailed chemical and radionuclidic analysis. Due to its expense and limited availability, (100)MoO(4)(2-) was recovered in >90% yield using a precipitation/filtration/lyophilization approach.


CONCLUSIONS
Na[(99m)Tc]TcO(4) was produced using a medical cyclotron, recovered using an automated purification module and found to exceed all established quality control parameters.
Nuclear Medicine, TRIUMF, Vancouver, BC, Canada.
Thomas J
TJ
Morley
Maurice
M
Dodd
Katherine
K
Gagnon
Vicky
V
Hanemaayer
John
J
Wilson
Stephen A
SA
McQuarrie
Wade
W
English
Thomas J
TJ
Ruth
François
F
Bénard
Paul
P
Schaffer
D001331:Automation; D005591:Chemical Fractionation / Q000379:methods*; D002852:Chromatography, Ion Exchange; D017357:Cyclotrons; D007475:Ion Exchange Resins / Q000737:chemistry; D008982:Molybdenum / Q000302:isolation & purification; D011786:Quality Control; D013670:Sodium Pertechnetate Tc 99m / Q000737:chemistry / Q000302:isolation & purification*
D007475:Ion Exchange Resins; C044659:molybdate; D008982:Molybdenum; D013670:Sodium Pertechnetate Tc 99m