Abstract The development of orthogonal planar strip high purity germanium (HPGe) detectors offers the advantages of good energy and three dimensional spatial resolution of photon interactions. The use of such devices for Positron emission Tomography (PET) are being investigated by the SmartPET collaboration. This paper presents initial results for algorithms developed to analyse the detector signals which recover the interaction position and energy, and the effects of strip geometry on these quantities. The aim is to develop a tool to aid design decisions, provide estimates of uncertainty, and resolve event position to better than 1 mm.