An X-ray or infrared imagery apparatus that performs a large sweep while reducing the irradiation or illumination dose. It comprises a support, an X-ray or light ray source that emits a beam through a slit of a dose limiter which is driven in translation, a detector irradiated or illuminated by the beam in order to detect an intensity attenuated along the X-ray or light ray propagation path through the body, an analog-to-digital converter to convert the detected intensities into data in order to determine an attenuation of the X-rays or light rays by the body, and a programmed computer to process the data in order to obtain an image representing the attenuation of the X-rays or light rays. The dose limiter either is driven in translation at a speed proportional to the detector or driven in translation at the same speed than the detector in front of a reflector.