Quantum dots excitation using pure beta minus radioisotopes emitting Cerenkov radiation.

Cerenkov radiation imaging has been recently introduced as a new pre-clinical imaging tool to investigate many pathologies in vivo. It is well known that Cerenkov radiation is more intense at shorter wavelength than at longer wavelength in the visible range and, thus, in order to improve the detectability in biological tissues a shift towards the red and near infrared emission is needed. The use of Quantum Dot (QD) nanoparticles as Stokes shifters has been previously suggested, but the interaction mechanism with Cerenkov radiation was not fully investigated. Our experimental results showed a good agreement with the inverse squared law and, thus, we conclude that the excitation of QDs with a beta emitter is quite similar to the fluorescence by unbound excitation from the luminescence mechanism