The relation relates to a method and a radiological imaging device. A subject (4) is illuminated by a luminous flux (1) generated by an X-ray source (2). This luminous flux (1) is a pulse having a duration t.sub.p shorter than 1 ms. The signals S derived from the interaction of the luminous flux (1) with the subject (4) are then detected by means of an X-ray detector (5) having a response time t.sub.r shorter than 0.1 ms.Applications possible in medical imaging (mammography, dental care, . . . ).