Physical Performance of an Intraoperative Beta Probe Dedicated to Glioma Radioguided Surgery

Abstract

The precise delineation and excision of brain tumor extent allows to improve survival outcome and quality of life of surgically treated patients. In order to refine the resection of gliomas, we are developing a novel intraoperative probe specifically dedicated to the localization of residual tumor after the bulk has been excised. The probe, built around clear and plastic scintillating fibers, was designed to detect positrons emitted from radiolabeled brain tissue in order to discriminate more specifically neoplastic from normal tissues. The probe was also built to be directly coupled to the excision tool leading to simultaneous detection and removal of tumor. We report here performances of the first radio-isotopic configuration of the intraoperative probe which consists of a detection head composed of eight detection elements held around the excision tool in a closed packed annular arrangement. This head is coupled to an optic fiber bundle that exports the scintillating light to a multi-channel photomultiplier tube. The ray background generated by the annihilation of + in tissues is eliminated by a real-time subtraction method. The detector exhibits a sensitivity of 139 cps/kBq and a ray rejection efficiency of 99.5%. The ability of the probe to detect residual lesions was evaluated with a realistic brain phantom representing the surgical cavity and the boundaries of the tumor. We showed that lesions as small as 5 mm in diameter can be detected for tumor to normal tissue uptake ratios of fluorinated tracers greater than 3.5. This ratio is achieved with radiopharmaceuticals like 18 F-FET or 18 F-choline. These promising results suggest that the features of our system are compatible with in situ localization of residual radiolabeled tumors.

Cerenkov radiation imaging as a method for quantitative measurements of beta particles in a microfluidic chip

“…Some devices were developed for imaging radioactivity distribution in tissue sections and have been commercialized (Cabello et al 2007, Kvinnsland et al 2002, Breskin 2000). Some were developed for intra-operative beta particle detection to assist in tumor localization during clinical surgery (Daghighian et al 1994, Raylmann 2000, Bogalhas et al 2008). However, few devices were optimized for microfluidic chip imaging (Cho et al 2006, 2007, Vu et al 2006, 2007, Laven et al 2004, 2005).…”

Characterization and Optimization of silicon photomultipliers for the development of intraoperative beta probes

“…4). This amount of scintillation light can only be collected by reducing the number of optical interfaces between the organic crystal and the photosensor and especially, by avoiding any light guide between them [8]. When extreme miniaturization of the detection system is not required, the 3 Â 3 mm 2 SiPM with 50 mm size cells appears as the best compromise between sensitivity and light collection.…”

“…The model was validated by comparison to measurements performed using an additional experimental setup that has been described in Ref. [8]. A 10 cm long, 2 mm diameter plastic scintillating fiber (BCF 12, Bicron) is optically coupled to the MPPC33-50 and irradiated with a 204 Tl source placed at 5 mm from its tip.…”

Quantitative assessment of Cerenkov luminescence for radioguided brain tumor resection surgery

“…An obvious use is to locate tumor margins during the course of oncologic surgery, and given the abundance of tumor-specific radionuclides (Gulyas and Halldin 2012), this is an appealing application. Radioguided surgery via e +/− or gamma detection has been actively explored (Hoffman et al 1999, Menard 2011, Bogalhas et al 2008, Povoski et al 2009). Additionally, several groups have also demonstrated instrumentation or feasibility of this concept using Cerenkov luminescence (Holland et al 2011, Liu et al 2012, Thorek et al 2014).…”