RRR RADIATION STANDARDS, INCLUDING FALLOUT 19 tion admitted that approximately 90 percent of the medical and dental X-ray equipment was in disrepair; as a consequence, spreading more radiation than was calculated. Is this figure b on the theoretical performance of machinery in good condition or the actual performance in bad condition ? Dr. Tayzor. I can’t answer that. I know that at least in a few cases the information that were supplied was what you might call across-the-board equipment. I am sure that you will find isolated cases where the equipmentis not as good as it should be. On the other hand,with the great bulk of the equipment in the United States which has rather rapid obsolescence, we have quite good built-in inherent protection. The use of radiation equipment by the medical profession is something else again. This is something that is very hard to get at. Iam sure that you will find cases where radiation exposure is delivered unnecessarily. I don’t think that you can put a high degree of reliance on these figures but I doubt you will find they are out by a factor of more than two, and that is not very important. Representative Hosmer. Thefigures range from 10 to 50 percent of background ; you have lot of leeway. Dr. Taytor. That varies between countries. This is about the degree of uncertainty, as a matter of fact, in making the estimates. On the other hand, there is a fair certainty that it 1s somewhere in the neighborhood of 50 percent of background or less now as compared with the estimates a few years ago of 120 percent of background. Representative Hosmer. Is this an improvement in the estimates or an improvementin the techniques and equipment ? Dr. Taytor. I would say mainly an improvement in the estimates because I don’t think there have been enormous changes in equipmentin that length of time. Representative Hosmer. You just testified that there has been magnificent improvement. Representative Price. We will have testimony later on in the hearing on the equipment from Dr. Richard Chamberlain. I think he will cover the equipment. Representative Hosmer. I am trying to substantiate this figure, Mr. Chairman, which appears to be pretty much of a “guesstimate” rather than a real estimate. Senator Anperson. Could I ask one question there? _ I want to follow exactly what Mr. Hosmer has been asking, whether it is an estimate or a “guesstimate.” You are with the National Bureau of Standards. You said these were U.N. figures, How much did you check into the U.N. figures? Did you take them just as they came? Dr. Tayztor. The Bureau of Standards is not involved in this. Senator Anperson, Whois involved in it? Dr, Tartor. The International Commission on Radiological Protein has studied this and we have done some verification in the ICRU. Senator ANDERson. They met at Stockholm? Dr. Taytor. Yes. Senator Anperson. Did they accept these figures ? Dr. Tayzor. These figures were not discussed then. gesREEgiAGSERABIRSRRHEN

Select target paragraph3