EasyPET is a simple, user friendly and portable didactic PET system developed for high-level education, which allows exploring the physical and technological principles of the conventional human PET scanners, using the same basic detectors of state-of- the-art systems. The Positron Emission Tomography (PET) scanner is the state-of-the-art medical imaging system, capable of providing detailed functional information of physiological processes inside the human body. Functional imaging has a great impact in cancer diagnostics, monitoring of therapy effects and cancer drug development. The underlying principle to PET systems is the detection of high energy radiation emitted from a chemical marker, a molecule labelled with a radioisotope, administered to a patient. The radioisotope emits positrons which, after annihilating with atomic electrons, result in the isotropic emission of two photons back to back with an energy of 511 keV. The two photons are detected by a ring of detectors, which allows a pair of them to detect two back to back photons in any direction.