Construction and Characterization of a Novel Single Pixel Beta Detector for Intraoperative Guidance in Breast-Conserving Surgery

Breast-conserving surgery is imprecise requiring re-excision in up to 40% of cases. One potential method of improving breast-conserving surgery accuracy is to use a beta particle detector to evaluate the surface of the excised tissue for any cancerous deposits, intraoperatively. Patients could be injected with a radiopharmaceutical that emits beta particles and preferentially accumulates within cancer cells. Cancer cells found on the surface of the excised tissue indicate that the surgery is incomplete. The purpose of this paper is to develop and analyze a novel single pixel beta sensitive detector. The detector is made up of a calcium fluoride europium doped [CaF
²
(Eu)] scintillation crystal, which is coupled to a silicon photomultiplier. A computational model of the detector response was derived from an empirically generated, 2-D, detector sensitivity map. This study determined that a CaF
²
(Eu) scintillator of 0.5-mm thickness provided superior beta to gamma detection ratio. According to the detector response, it is expected that with an acquisition time of 30 s, the tumor-to-background ratio of 5 or higher, and a normal breast tissue activity of 1.69 kBq/ml, less than 1 mm
²
tumor detection is achievable. The result of this paper indicates that the radio-guided surgery with a CaF
²
(Eu) scintillation detector could be feasible to intraoperatively assess tumor margin involvement.