Dose Rate Determination of Gamma Rays Emitted by Thallium-201 and Technetium-99m Using a Modified Horseradish Peroxidase Based Biosensing System

In the presence of low energy gamma emitter radioisotopes of thallium-201 (201Tl) or technetium-99m (99mTc), H2O2 was generated via radiolysis of water. The produced H2O2 was amperometrically determined using an anthraquinone 2-carboxylic acid modified horseradish peroxidase on glassy carbon electrode. In the presence of each radioisotope, the cathodic current produced due to the amperometric detection of H2O2, was designated as biosensor response. At the applied potential of -550 mV (vs. Ag/AgCl), the biosensor showed the sensitivities of 1.937 and 2.278 nA h �µGy-1 towards H2O2 produced by 201Tl and 99mTc respectively. Finally, the calibration curves for dose rate determination of 201Tl and 99mTc have been presented and the correlations between biosensor response to H2O2 and the gamma emitter dose rates for 201Tl and 99mTc are established.