Digital Signal and Image Processing in Jagiellonian Positron Emission TomographyPositron Emission Tomography (PET) is a key technique in the medical imaging area, which allows to diagnose the organism functions and to track the tumor changes. In PET measurement the patient is injected with radiotracer, containing a large number of metastable atoms of radionuclide, that emmits positrons. As the result of positron annihilation, the two photons travelling off with nearly opposite directions are produced and registered by detection