Use of a CMOS image sensor for beta-emitting radionuclide measurements

Radio-Guided Surgery enables the surgeon to identify tumor residuals in real time, with millimetric resolution. This technique takes advantage of a radiopharmaceutical as tracer and a probe as detector. The employment of β⁻ emitters as tracers, instead of γ or β⁺, reduces the background from the healthy tissues and the medical exposition risk. The performances of a CMOS sensor, the MT9V011, originally designed for visible light imaging, as β⁻ radiation detector have been investigated. In particular, we have studied the impact of an infra-red filter placed in front of the sensor in the existing commercial devices, and we have determined the sensitivity and spatial resolution of the sensor, in the presence of a localized ionization source of variable size. Finally, by evaluating the sensitivity to clinical-like activities and geometries we conclude that even with the small size of the sensor, that can potentially be increased, the acquisition time required to discriminate a tumor residual from healthy tissues is of a few seconds for transverse dimensions greater than 3 mm.