GB777350A - Improvements in or relating to medical diagnoses - Google Patents

Abstract

777,350. Diagnostic apparatus. SCHWAMM, E., and REEH, J. J. June 14, 1954 [July 3, 1953; Oct. 20, 1953; Nov. 21, 1953; Dec. 16, 1953], No. 17467/54. Class 81(2) [Also in Group XL(b)] A diagnostic appliance comprises means for measuring the intensity of infra-red radiation at various frequencies emitted by particular parts of the body. Any form of radiation-sensitive element may be employed and, in the diagrammatic arrangement shown it consists of a coating of bismuth on a thin film 6, so placed in an evacuated bulb 4 as to receive radiation through a quartz window 5. Its resistance is balanced by a similar element 7 in a bridge circuit consisting also of resistances 8, 9. A.C. is applied across the bridge and the output is amplified by valve 11 and rectified by valve 16 to control a measuring instrument 17. The open end of a tube 19 is placed against the body and the particular band of frequencies being investigated is determined by an exchangeable filter 20. In modified forms provision is made for focusing the radiation on the sensitive element by lenses or mirrors and for the inclusion of a manually operable shutter. It is further proposed to surround the radiation-receiving end of the instrument with a cylindrical mass of metal, so as to prevent the temperature of the instrument rising as a result of continued exposure to radiation, and, in the case of relatively low frequency radiation, a rotating, apertured disc is set in the path of the received rays to modulate them at a desired freauency and thus make them more readily detectable.