Fast Gamma-Ray Event Interaction Position Estimation Using K-D Tree - A Simulation Study

We have developed a gamma-ray interaction-position estimation method using k-d tree search, which can achieve efficiency and accuracy at the same time. This method can be combined with various kinds of closeness metrics such as Euclidean distance, and maximum-likelihood estimation. The time complexity of the k-d tree search method is O(log(2)(N)), where N represents the number of entries in the reference data set. The accuracy of the k-d tree search is equivalent to that of the exhaustive search method which has the highest achievable accuracy. Most importantly, this method has no requirement on the shapes of mean-detector-response functions (MDRFs), which means that it is also very robust, and can be applied widely without restrictions.