Radioactivity counters and mono-channel probes

Over time, due to technological and methodological advances in medicine, surgical procedures have become increasingly precise and less invasive. Particularly, in the last decades, discoveries in chemistry and nuclear physics brought to groundbreaking advances in the oncological and diagnostic field. Considering surgery represents the principal treatment for cancer, several techniques and technologies are being developed to improve its effectiveness, mainly by enhancing the completeness of the tumor resection. In this context, the application of minimally invasive surgical techniques, where applicable, has become established because they result in greater tissue preservation, fewer side effects and morbidity, and comparably shorter recovery times. The radioguided surgery (RGS) concept, which was first developed some 60 years ago, can be seen as a result of this trend. It leads to minimally invasiveness by the utilization of a radiation detection device inside the operating room to identify in real-time the tissue with significant radioactive uptake due to the administration of an ad-hoc radiotracer to the patient beforehand. In the present chapter, various topics have been addressed, ranging from the origins of RGS to its clinical applications and, then, mentioning the historical and technological progress of radioactivity counters, classified into gamma and beta probes, whose operation has been concisely described. The chapter ends with a brief overview of the latest innovative counting probe detectors and a glimpse into the future of radioactivity counters taking into account performance and limitations and giving some perspectives that could guide future improvements and implementation of the probe in a clinical setting.