The thermo detector to measure mass includes a housing for holding an infrared sensor for detecting infrared radiation emitted by a patient. The emitted infrared radiation is used to distinguish between fat and muscle of the patient in a selected body part based upon variations in temperature represented by the detected infrared radiation. A laser is further disposed in the housing for projecting a scanning laser beam on the selected body part of the patient, and at least one laser sensor receives a reflected laser beam from the selected part of the patient. From the reflected laser beam, a volume of the fat and a volume of the muscle of the selected body part based on the reflected laser beam are determined. A mass of the fat and a mass of the muscle in the selected body part of the patient are then determined based on the detected volumes thereof.
