18F autoradiography with the Mimosa-28: Characterisation and Application

Autoradiography (AR) is a technique used to record the spatial distribution of a radiotracer into an ex-vivo tissue slice. Within the section, the radioactive molecules emit charged particles from specific binding sites. These particles pass through the tissue before being detected by a sensor. AR gives the distribution of a radioactive molecule with a spatial resolution of approximately one hundred microns. In this article, we investigated the feasibility of AR with a CMOS-APS sensor using radioactive isotope 18F. This sensor works in digital mode by collecting charges. It presents a linear response with isotope 18F for activity between 1 kBq and 1 MBq. The detection efficiency is 44,0 ± 0.5% for this range of activity with a spatial resolution of 144 ± 3 $\mu \text{m}$ by using the absorber edge method. The Mimosa-28 sensor performs AR imaging with a rose leaf and a mouse brain section which has a thickness of $50~\mu \text{m}$ and an activity of 4 kBq in the slice.