This work deals with the rejection of events interacting more than one time in a crystal array, by using the method introduced in the paper R. Scafè et al.(2016). In particular the grade of symmetry of charge distributions along the X and Y axes was successfully used for discrimination. Results are presented regarding a 10× 10 LuYAP: Ce array of 2× 2× 10 m m 3 crystal-pixels coupled to a H10966 Hamamatsu 8× 8 multi-anode assembly under gamma-ray irradiation from a Co-57 radioisotopic source. Filtered pulse-height spectra are shown characterized by relevant rejection of low-amplitude events. In this region of spectrum, asymmetrical charge distributions were measured due to lutetium and yttrium X-rays escape from lateral walls of crystal-pixels. Events from Lu-176 self activity above the Co-57 photoelectric peak were also rejected. Similar results are reasonably expected at PET photon energy.