Document YjR133XXqBOxGEzGeXjqw5p4E

718 LEON F. CURTISS 5. Screening Complete Rooms In some situations it is desirable to line with lead, or equivalent material^ a complete room in which an x-ray tube is located to provide protection, in ad-i, jacent rooms, from the scattered radiation. Where this is done, the protective material should be joined in a lapped joint; and all perforations, such as nail, holes, should be adequately covered with lead. Lap joints that leave no unob'i structed path for x-rays also should be provided at the doors of such a room! The thickness of this material should conform approximately to the figures give* in Table 6. 6. Ventilation In x-ray installations where corona discharge may generate noxious gase such as oxides of nitrogen and ozone, forced ventilation is required. Such a co dition exists where high voltage conductors are exposed in the air. Under usif: conditions, the rate of change of air ordinarily recommended for general veil? tilation, four or five changes per hour, will be sufficient to reduce these ga' below the level where any discomfort or harmful exposure will result. % 7. Special Conditions It is impossible to suggest, within a reasonable space, rules that will am to all conditions. As conditions change, either regarding tolerance levels or tyg of generating equipment, the National Radiation Protection CommitteeUsr handbooks that cover the more important cases. A list of these handfcMK published by the National Bureau of Standards appears at the end oi.||T chapter. Where unusually high voltages are used, or other exceptional fea^j are present in ja generating installation, safety can be assured only by carbf measurements by specialists of exposure at stations occupied by personnel ,uh actual operating conditions. Lead thicknesses given by Kaye7 for x-ray voltag up to 5 Mev. are included in Table 6. ,ri|Sr 8. Unnecessary Hazards Under this title should be.con8ider.ed-those.uses-or misuses-of-xradiati|& serve no real purpose and unnecessarily expose individuals to poss.iWpj It is needless to say that all such procedures should be discouraged. IVb exfimp may be cited to illustrate. In some shoe stores, x-ray machines, under nq^e* supervision, are occasionally .used to permit customers to examine tKe.'Js ol their feet by means of a nuoroscope after fitting new shoes. Since 00'$!* is set on the duration of such exposures, it is surprising that numerous cag injury have not come to light. Another illustration occurred during World G. W. C. Kaye, Nature, 145, 370 (1940). RADIANT ENERGY 719 ggggjjjiMn a large industrial plant where employees were permitted to use a medical '`||ay installation to examine themselves for metal splinters, or make any other Sjfeyjjijati' of the machine that struck their fancy. This occasioned an outbreak of |jjj|l^t(Jere radiation dermatitis, and possibly other injuries that were not immediately btified by examining physicians. Considerable damage was done before a |^^p|fect diagnosis led to the cause and the practice of self-examination was dis- ggsjKjpntlinued. The obvious conclusion from all such incidents is that no x-ray $tt iMpchine should be operated by other than a trained technician well aware of gpJ||liinits of safe exposure and of the consequences of overexposure. Furthermore, ^^ffiitechnician should be responsible for the enforcement of adequately safe pro- in all operations involving the use of x-ray equipment. In no other way certain degree of carelessness, either through ignorance or foolhardiness, llfftevented. III. Infrared Radiation a A. GENERAL EFFECT The long wave lengths of infrared (heat) radiation can inflict no deep Sies in the human body, since they are readily absorbed by the surface Hues. Although the full effects on the surface tissues do not develop for al hours, there is almost immediately some discomfort associated with iexposure to this type of radiation. This discomfort gives adequate warning Jpas general bodily injury is concerned. The eyes, however, may suffer from aL,.exposures,.ta,infiar.e(L.radiation.,.that .is. well .below the level that 1,general discomfort or injury. There is some evidence that this may result Cataract.8 Dunn, however, found no cataract from infrared in the glass pltry. plthough only a small portion of the energy is absorbed in the. lens of the lens cannot lose heat readily. An additional injury is a permanent Is, of the retina, most likely to occur in unprotected.;eyes exposedto.veijilong ,1' at some distance from the source of radiation. ^OrtunatelyJlinSifiost (fobs where overexposure of eyes to infrared radiatiori Imay dcquh,divisible also is so intense as to require protective goggles.;,ihis mayr.notiaiways ei*Where sources of infrared are:eHbuntered in 'riciiE%iis''0p'ei'iii:jii'(i^l]^8UCh ^hp.eratur.eJ,hat45ttle^sMe^ght^isaemittMpspbaS'EltbSiSffi^ust'.i:Be. he protection of the eyes. B. PROTECTIVE. MEASURES . .... Hjifeteffects of excessive heat on bodily.icomfort'and resistanC'AOafi^fetieduced b^ta'kin^salfPtablefcs^-Ahd-^dSnkihg-^plehtj^bf--vSterS-fo'-^replaee- llSfirefttional losses due to perspiration (see page 119). ; ..... Js|^$i''Kealing, J. Pearson, J. Simons, and E. E. White, AMA. ArcK^Ind.'ttedti'h, 11,' Dunn, Arch. Jnd. Hyg. and Occupational Med., 1, 166 (1950).