Performance of a Gamma Detection Unit with Likelihood-Based Localization Method

In this paper a new gamma detector for combination with ultrasound imaging to localize radioactively marked lymph nodes is presented. The detector consists of six silicon photomultiplier diodes arranged around a rectangle, to fit an ultrasound device in the center. The localization is calculated depending on a probability field. The system was evaluated with a Co-57 gamma source, which was positioned in a 3 times 3 matrix for three different distances. The position estimation achieves an euclidean error of 2 - 47 mm dependent on the position and distance.