Physical Performance Parameters of Intraoperative Probes

In 1951, the neurosurgeon William Sweet described the value of intraoperative gamma probes to demarcate brain tumors in the operating room (1). Since then the increase of applications, especially sentinel lymph node biopsy, has prompted a number of commercial manufacturers to offer intraoperative probes for radioguided surgery (2). Their basic physical principle relies on a radiation detector (usually a scintillator or semiconductor detector) and associated electronics to provide a visual and auditory signal related to the amount of radiation detected (3). Many investigators have compared the performance of these instruments (4)–(9), and some have suggested using a figure of merit (10)–(12). This chapter summarizes the most important characteristics of non-imaging intraoperative gamma probes. The performance of the most widely used models is discussed in detail, to assist in the selection of one that best fits a specific application. In order to make such a comparison rigorously objective, a set of well defined experimental conditions was developed, and this goal constitutes the core of the Italian protocol for quality control of intraoperative probes.