How To Choose a Probe

Abstract

Intra-operative gamma probes are increasingly used to localise the first draining lymph node from a tumour, the sentinel node, in melanoma and breast cancer [1 – 5]. A wide range of probe systems are available with different detector materials, detector sizes and collimation, and evaluation is required prior to purchase and use. The basic physical probe performance can be described by the spatial resolution, sensitivity and count rate linearity [6]. Comparison of these parameters allows us to rank different systems in terms of relative performance for each parameter, but give us little insight into relative performance in localising sentinel nodes. For example, which probe is superior if one has a spatial resolution 5.6 mm better than the other but a 20% poorer sensitivity? This paper describes, validates and applies a methodology to allow comparison of probe performance in practical terms related to the task of sentinel node localisation in melanoma and breast cancer.

First published in Eur J Nucl Med 26,1999.