Radiological imaging device comprising - a gantry defining an analysis zone suitable to contain at least the portion of the patient to be analysed and a circular trajectory of extension extending around a central axis; - said gantry comprising ∘ an image acquisition unit comprising at least a detector suitable to receive an emission after said emission has traversed at least part of said analysis zone; and ∘ a casing defining a housing volume for said at least one detector; - characterised in that said casing is of the telescopic type and comprises - a curved base module, - at least one curved mobile module (232a, 232b) movable relative to said curved base module so as to vary the angular extension of said casing and, thus, of said housing volume while maintaining said image acquisition unit inside said housing volume; - said least one curved mobile module (232a, 232b) having a cross section different from the cross section of said curved base module so as to be at least partially superimposed on said curved base module; - and in that said gantry comprises, housed inside said housing volume, - at least one carriage (24a, 24b) to which said image acquisition unit is attached; - a base guideway integral with said base module and defining a base sliding trajectory for said at least one carriage (24a, 24b) in said base module; and - a mobile guideway integral with and inside the at least one curved mobile module (232a, 232b) and defining a mobile sliding trajectory for said at least one carriage (24a, 24b) in said curved mobile module (232a, 232b). - a gantry defining an analysis zone suitable to contain at least the portion of the patient to be analysed and a circular trajectory of extension extending around a central axis; - said gantry comprising ∘ an image acquisition unit comprising at least a detector suitable to receive an emission after said emission has traversed at least part of said analysis zone; and ∘ a casing defining a housing volume for said at least one detector; ∘ an image acquisition unit comprising at least a detector suitable to receive an emission after said emission has traversed at least part of said analysis zone; and ∘ a casing defining a housing volume for said at least one detector; - characterised in that said casing is of the telescopic type and comprises - a curved base module, - at least one curved mobile module (232a, 232b) movable relative to said curved base module so as to vary the angular extension of said casing and, thus, of said housing volume while maintaining said image acquisition unit inside said housing volume; - said least one curved mobile module (232a, 232b) having a cross section different from the cross section of said curved base module so as to be at least partially superimposed on said curved base module; - and in that said gantry comprises, housed inside said housing volume, - at least one carriage (24a, 24b) to which said image acquisition unit is attached; - a base guideway integral with said base module and defining a base sliding trajectory for said at least one carriage (24a, 24b) in said base module; and - a mobile guideway integral with and inside the at least one curved mobile module (232a, 232b) and defining a mobile sliding trajectory for said at least one carriage (24a, 24b) in said curved mobile module (232a, 232b).