A
system for treating a selected dermatologic problem and a head for use with such
system are provided. The head may include an optical
waveguide having a first end to which EM
radiation appropriate for treating the condition is applied. The
waveguide also has a
skin-contacting second end opposite the first end, a temperature sensor being located within a few millimeters, and preferably within 1 to 2 millimeters, of the second end of the
waveguide. A temperature sensor may be similarly located in other
skin contacting portions of the head. A mechanism is preferably also provided for removing heat from the waveguide and, for preferred embodiments, the second end of the head which is in contact with the
skin has a reflection aperture which is substantially as great as the
radiation back-scatter aperture from the patient's skin. Such aperture may be the aperture at the second end of the waveguide or a reflection plate or surface of appropriate size may surround the waveguide or other light path at its second end. The portion of the back-scattered
radiation entering the waveguide is substantially internally reflected therein, with a reflector being provided, preferably at the first end of the waveguide, for returning back-
scattered light to the patient's skin. The reflector may be angle dependent so as to more strongly reflect back
scattered light more perpendicular to the
skin surface than back scattered radiation more parallel to the
skin surface. Controls are also provided responsive to the
temperature sensing for determining temperature at a predetermined depth in the patient's skin, for example at the DE junction, and for utilizing this information to detect good
thermal contact between the head and the patient's skin and to otherwise
control treatment. The head may also have a mechanism for forming a reflecting chamber under the waveguide and drawing a fold of skin therein, or for providing a second enlarged waveguide to expand the optical aperture of the radiation.