Arthritis inflammation monitored by subcutaneous millimeter wave thermography

A new technique for remote, noninvasive mapping of temperature elevations of the human joints is described; it uses the mm wave radiation emitted by the human body. A solid state switched scanner for 68 GHz is described which overcomes the depth limitations of conventional, infrared thermographs and can measure to subcutaneous depths of several mm with a temperature resolution of 0.25 degrees C. Measurements on rheumatoid arthritic knee joints are presented which show little correlation with simultaneously measured skin temperatures. Significant longterm thermographic changes induced by steroid injection indicate a potential for objective patient monitoring and development of new treatment methods.