A computer controlled automated dispensor for the eluting, calibrating and dispensing of 99Tcm-pertechnetate

This paper describes an automated 99Tcm-Dispensor, a computer controlled device for the programmed, automated elution of 99Tcm-sodium pertechnetate, its calibration, metered delivery and dilution. The elution can be programmed up to 7 days in advance. The total radioactivity of the eluate is assayed by a semiconductor counter integrated in the shielding of the pertechnetate reservoir. The volume of eluate actually available for dispensing is measured by capacitance and is monitored continuously. The specific concentration is calculated from total activity and volume, and is corrected for decay prior to each delivery. All activity bearing sections are shielded by lead-antimony covers specified to attenuate the radiation from generators up to 2 Ci 99Mo/99Tcm. The labelling vials are inserted into the dispensing chamber within a shielding vessel manually. The sodium pertechnetate solution is dispensed prior to the optional additional delivery of normal saline. The Tc-Dispensor maintains sterility, guards against accidental radioactive contamination, and is suited to reduce the radiation burden of personnel. All operations are recorded by the computer enabling the print-out of protocols. We found the Tc-Dispensor safe, precise and accurate.