The device (10) comprises a first detector (16) for a measurement on a thyroid and a second detector (18) for a measurement on a thorax. It comprises a portable device (14) for supporting detectors, comprising: a transverse support crossmember (20), —at least one support leg (22) carrying said support cross-member (20), and —a support member (28), borne by the crossmember (20), including first (28A) and second (28B) portions movable relative to one another in a longitudinal direction (X), the first movable portion (28A) bearing the first detector (16), and the second movable portion (28B) bearing the second detector (18).