Feasibility of a beta-gamma digital imaging probe for radioguided surgery

We report here on a novel design of a digital, intraoperative imaging probe intended for use in radio-guided surgical procedures in conjunction with radiolabels such as ¹³¹I and ¹⁸F. The probe allows the user to rapidly localize tumors by detecting the highly penetrating gamma rays, and then image the tumor with the short-range beta rays. The system provides a rapid, high-resolution, image of the interrogated area, fulfilling the need for clear delineation of tumors during radio-guided surgical procedures. The beta imaging sensor consists of a microcolumnar CsI(Tl) scintillator screen capable of providing very high detection efficiency, high light output and excellent spatial resolution coupled to a CCD via a flexible, coherent fiberoptic bundle. The gamma sensor is a shielded piece of crystalline CsI(Tl) coupled to a photodiode located behind the image sensitive front end. The feasibility of this design was studied by separately testing the beta imaging and gamma detection components. The operation of the components was characterized with intrinsic performance measurements of count rates, signal-to-noise ratios, spatial resolution, as well as time for acquiring useful images using radionuclide and anthropomorphic phantoms.