An imaging and treatment head for imaging and treating an organ or tissue of a living being, and usable in particular for treating tumors of the prostate or the thyroid. The head includes an ultrasonic probe suitable for emitting waves or radiation so as to provide an imaged representation of an organ or tissue for treatment. The head also includes a treatment mechanism suitable for treating the organ or tissue locally. The treatment mechanism is suitable for emitting waves or radiation so as to treat the organ or the tissue. The head is characterized in that the ultrasonic probe is mounted in a removable manner on an adapter that ensures positioning of the ultrasonic probe relative to the treatment mechanism.