Abstract: A portable radiological cassette is designed to equip a digital radiological system. The cassette comprises a digital ionizing radiation detector in the form of a flat panel which makes it possible to provide an image which depends on the radiation received, with an electronic board ensuring the control of the digital detector, and a casing ensuring the mechanical protection of the detector and the electronic board. The cassette additionally comprises a flat seating which supports the detector on a first one of its main faces, and supports the electronic board on a second one of its main faces, the two main faces being opposite. The seating is formed by a heterogeneous stack produced such that the surface thermal conductivity of the seating is greater than the transverse thermal conductivity of the seating.