GATE is an advanced opensource software developed by the international OpenGATE collaboration and dedicated to numerical simulations in medical imaging and radiotherapy. It currently supports simulations of Emission Tomography (Positron Emission Tomography - PET and Single Photon Emission Computed Tomography - SPECT), Computed Tomography (CT) and Radiotherapy experiments. Using an easy-to-learn macro mechanism to configurate simple or highly sophisticated experimental settings, GATE now plays a key role in the design of new medical imaging devices, in the optimization of acquisition protocols and in the development and assessment of image reconstruction algorithms and correction techniques. It can also be used for dose calculation in radiotherapy experiments.

The OpenGATE collaboration has been awarded in 2009 the Physics in Medicine and Biology (PMB) Citazions Prize for the research paper "GATE: a simulation toolkit for PET and SPECT". The annual prize is presented to the authors of the PMB research paper that received the most citations in the preceding five years (according to ISI).