A scintigraphic device includes a case open at an application end, and coated by a shielding shell; a collimator positioned inside the case, made of a material with high atomic number and high density and having a plurality of collimation channels extending mutually parallel according to a predefined direction of measurement; a measuring member positioned inside the case in proximity to the collimator and including a scintillation crystal for converting each ionizing radiation originating from a source in exam into light radiation, and at least one photosensor, for determining the energy and the position of each detected event. The measuring member and the collimator are relatively movable to increase and/or reduce the distance between the converter and the application end and consequently to vary the total length of the collimator. The collimator may include two or more blocks at least one of which is movable relative to the others.