Reply to 'Comments on Cerenkov radiation allows in vivo optical imaging of positron emitting radiotracers'

In this reply, we address the criticisms by Drs Mitchell, Gill and Cherry (Mitchell et al 2010 Phys. Med. Biol. 55 L43-4) regarding our paper recently published in Physics Medicine and Biology (Spinelli et al 2010 Phys. Med. Biol. 55 483-95). In our paper we showed that it is possible to acquire Cerenkov radiation images of mice injected with 18F-FDG using an optical imaging device. We also showed two different approaches that can be used in order to estimate the depth of the Cerenkov radiation source inside the mouse. More precisely, we will discuss the criticisms regarding the proposed model of the Cerenkov radiation spectrum for positron emitters and the estimation methods of the radiation source depth by providing further experimental results. (letter to the editor)