§ Mr. Masonasked the Minister of Health to what extent dosemeters, as used by radiologists in the National Health Service, have been under-registering when measuring the strength of radiations given off by X-rays; how long these dosemeters have been faulty; when the discovery of this defect was made; and if he will make a statement.
§ Miss Hornsby-SmithMy right hon. Friend is advised that as a result of scientific research both in this country and in the U.S.A., early in 1953, it was found desirable to calibrate dosemeters in terms of a modified standard, differing from the old standard by a few per cent. This does not mean that dosemeters themselves were faulty. As regards hospital treatment, the radio-therapist will still give the same dose as he would have done before 1953, knowing the new calibration. The scientific work leading to the changes is now well known and is the basis of current calibration.