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Home , Ultra high frequency

Cataracts and Ultra-High- Radiation_j

DAVI·~ G. COGAN, M.D.; STEPHEN J. FRICKER, Sc.D.; MARTIN LUBIN, M.D., Ph.D.; DAVE-· D. ~SON, M.D., and HARRIET HAR:>Y, M.D., Boston - ]) I R,.lar and communication installations The. objectiw in the present study was to are , ,aking use of increasing amounts of detennine whether or not cataracts might pow, ·. · As· a rcs~lt, military and civilian result from exposure of ·tJ1e whole body to popu':1tions· may be· expo~d to larger doses radi.ation at similar to those of r:v:io frequency ener.gy_ .. S.uch.exposui:es .... used ••in wme···higfr-power ·installations. The ·will i,e to the body as 'a~whole; The fre- . inuned_iate concern was·with a frequency in qu;n,ies used probably will range from the the range o·f 400 megacycles (Mc;).. Par­ ·ultra-high-frequency band, a(a few hundred ticular interest lay iri · comparing the dose ·111ega, ycks per second, to the which produces· cataracts with that which band at several thousand megacycles per causes dt:·ath, for if the cataractogenic dose >t"COll

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E FOR PURPOSES OF S;UD; OR RESEARCH IN LIEU OF LEN_°.ING THE ~RIGl1' .~·· .. /. • I •.·.•1' ••

·.t•·-\: ~ -1 • r:~·: ~ .. ..,,,. Calaracts and Ultra-Hi'gh-Frc,1uency Radiatiol!J

oAvrr, G. COGAN, M.D.; STEPHEN J, FRICKER, Sc.D.; MARTIN LUBIN, M.D., Ph.D., QAVlt, D. DONALDSON, tt\.D., and HARR.IET HARDY, M.D., Ba1tan

R:11::u· and rnmi1iunication · installations The ohjectin: in the present study was to arc ,. .,ki.ng use of increasing amounts· of detcnnine whether or not cataracts might po11•,· As a n·sult, military and civilian result from exposure een made with comparable 1iral i nportance · in human beings since _.l!:_~tJencies 6 in the ultra-high-frequency micnr, we radiation is usl,d therapeutically band. No cataracts were obsened in any of al~Jut he eye. There is one repoiitd case these animals, ·although they recei,·ed radia­ of cat:,, 1cts in a human being, allegedly due tion i.n near lethal amounts. However, the to miu,J\\ave irradiation/ but this probably paucity of reported observations directed ranriot be accep!cd as proved. In this re- to the problem of eye damage and the prac­ ported ,ase, the r.idiation intensity reaching tical importance of the problem warranted the ey,·, was difficult to estimate. Moreover, further study using present methods of the m,,rphologic changes in tht lenses were quantitati\-e ill\'estigation. nuclear cataracts and not what one· expects with r:•diation.* Material and Methods ---Am,,1,·d for publication Jan. 17, 1958. Most The ,. ·search in this document was ·supported of the exposures were carried out 11 i intly J.: the Army, Navy, and Air Force under in a waveguide system, but some were made ro111rac1 .·,ith the Massachusetts Institute of Tech­ in "free space." The term "free space" '~•logy, : .inroln Lahoratory. must be interprtted with some reservation. Howt Lahoratory of· Ophthalmology, Har\'ard In an attempt lledical •-;d,ool and Massacliu,setts Eye and Ear to duplicate actual exposure lnfinnar, ( Ors. Cogan and LJonaldson) ; Massa- conditions, the test animals were contained 0111se1ts ·, 11stitute of Technology, Lincoln Labora- in a small Lucite box placi:d in the vicinity 1111')· (D, Fricker); Occupational Medical Service, of the radiating antenna .. It was not possible liass:icl,;,:;e11~ Institute of Technology (Drs. Lubin to measure the power andHarciy). . absorbed by the ani­ mals _under these conditions. 'Since ti,e morphologic changes in rabbits' eyes \Vith the. wave­ /•roduced i,r ionizing and microwave irradiation are ~ide system, all of the energy was confined "milar, one would expect posterior subcapsular within known limits, so that power meas­ '.ataracts in human beings from microwa\'e radia­ urements could be made. Exposure in a tion simil:ir to those caused hy ionizing radiation. waveguide is not the same as exposure in

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!' I A. M. A .•·ll, am! talk directly in tenns of ahs,,rl,ed power,. 111 watts. Since it · is this arc different, but the advantages to bc~ gained power wh:•·h ·is rmiv~·rl(>t1. into heat, - it m;~y ha\·e· a more ul."·:ious from this were considered suf1ic1ently great physical _mtcqtrctation. However, thi·s q1t1n:ny is to justify its use. A brief disrnssiun of the ~l~)l rc~Hhl)~ 1nC:.L..,urc,J under free !-,pace com: :ions. electrical measurements and charar!l'ristics lhc s1tua11011 can he g-rcatly improved if ,;., RF of radiation follows. CJ1c.-rg'~_· can he confined in a rlosed sysiem :,;inn: then st;u11lanl tc'Clmiques arc availahle for .-.wrr Elrclriral Cl,,ir~ct,·rislics ,nf RF /?,ulialion mc;,su~etlll'nts: Tims, altJmug-h a cloSL~I sy.-.-:·m is RF radiation is a tcm1 covering a wide hand n~,t qmte the ~;unt· sysfem :ts tl~at which wo11. l gire of frequencies. For our JmrJ>.>ses the main regions. !1SC to a po~s1hlc hazard, its ;u.lva.ntag-c.,;;, fo, rncas­ arc the ultra-high-frequcnry 1,md. (UHF), up to nrcmcnl w~rc considcre1.1 grCat enough tu ,. 1~tih· approxiniately 1000 Mcps, ,u1d ·frrni1 1000 Mrp,s 111>­ its use. Some additional tests were carried ·,1ut i~ wards, usually referred to as the microwave re­ "free space." gion.t _ E:xpo.<11rc Teclmique When a dissipative dielectric is placed in. an (11) In W:l\'eguide: A waveguide is a h111low electromagnetic field, curr-ei~~~.are- induced in the metal pipe,. throi,gh \\'hich RF· power ca11-l;·.made dielectric. In· some few· idealized cases adequate .. to flow iu a well-defined p.,ttcn.1. \\/hen 11 mathematical representation will give the details :, ob­ st;1clc is pl;1ced in the guide of the process. However, .whatc~•<"r the · det.-tils, the pattem .,. ;,m·er flow is changed, since now there is son1e l the genl"ral principle remains:. e.tt~rents flowing in dcction as well as transmission. The basic ·featu:· · nf the dissipati,·c medium cause· heat to he produced. the exposure tcdmiquc 'is to take aicow1.t o: iht re­ Another factor to he considered coucems the re­ flection ·pr0tluced hy the obstacle by i11•,·•d11cing ·.r · I gions in which· the heat is producc"1. At· the f re- a tuning sect iuu, which essentially ·pro\'id,·; a can­ . que:ncy band in the experiments rCJ)()rtec expected that waveguide of cross section 15 X7¼ i~. .'. ·, personnel .... exposed to RF radiation will receive the (b) ln "Free Space": In this nw::,od RF exposure while in the viciniiy _of' an. antenna fed !lOwer was supplied to a horn radiator mounte" (UHF) for 300-300(>' Mcps, to those obtained with the >Vavq!;uide ex· posure. Because l and "super-high frequency" ( SHF) for 3000- of this and because oi the con· ~ 30,000 Mcps. It has been coinmon practice to refer venience of the w,iveguide system, m~st a1tention to the 3000 Mcps ceirion as "microwave," however, was given to the waveguide exposures. The and since most of th~ literature has ·follov.'ed this "free . space" exposures were carried out al a frequency of ~ practice it ·has been adopted here. 385 Mcps, rather than 4(.8 Mcps ;i; V ~I. 18, Ort., J958 ~ 300

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-~S A SINGLE PHOTOCOPY MADE BY THE NATIONAL LIBRARY OF MEDICI,.

'· [:/T.·INACTS AND ULTRA-1-//Gll-FRl:Q/JJ:NC}' RADIATION

Summary of Exposures le1hal doses. The rectal temper-«ture rose an aver­ age of 1.5-2 degrees ( C) during these exposuses. No;or \Veeks . Gro1_11,s A and B, no1ed l!a"'or No.of No.or or follow-Up in the t.al,le, represent a Exposure HuhUlts .Exposurt•s After Last to1al. of 184 cxJ,osun:s wi_th 23 r«bbits. An average . of the mcasi1nsnt111s on these animals gave a figure Group_,,,: Weekly 10 5-7 ,;f 8.1 walls/kilogram as the power absorbed, with wa,·eJ?;m•le at a. st;mdard deviai°ion of 1.25 watts/kilogram. Any oomwi11:-./cm •. 15 Controls particular 1or~m:1. ' measurement was accurate to within 10%, whi_le variations due lo movement of tl1e test Group J;· Dally 12 10 animal were of the same order of magnitude. l\;areJnf le at 15 Controls Power absnrpt oo ~1ni1 · :/cm•. ion measurements usually were taken lor~mk. at JO-minute intervals during each exposure. Rabbits in Group A received 60 mw/an.•, once Group C· Twice 10 4 weekly for. a to1al of five to seven weeks. Some ~•Free-sp:,te'~ ., . Weekly... 4. Controls- a1aoami-,;o · t. - rahbits·· die0sures (Tahle). Of 15 control ani­ These do ·s were nearly at th.e lethal level. mals, 4 died of infecli;ms disease. Autopsy results will be descril,ed in a future publication. in 1he P"ide, hut this difference in frequency is not In Group B ral,l,its were i'rradiated daily, with n-garde · as significant . the exr~1,1ion of a two-day week-end -interruption, Aduh male, albino rabhiis were used exclusi,·ely. for a total of JO exposures. The.se rabbits also The n1111-ber of rabbits used for eacl, exposure, the were given 60 mw/an.•, for 20 minutes at each nwnber ,,f exposures,_and the dosages are indicated exposure. Two of the controis bu1 none of the 12 in the ;, companying· table. irradiated animals died prior to the end of the ex­ The r :,_bits of groups A and B were sures were . carried out at 30 and 60 milli­ · irradia_tion ;md were as frequent in the con­ •,tts/on.', witl, the exposure durations arranged trol '' that th group as in the irradiated group. They e ra,11 nts· received. fairly. large but sub- were of such small dimensions that they r,g"" ti al. 301

E FORi P:t)RPOSES OF STUDY OR RESEARCH IN LIEU OF LEN_DING THE ~RIGI . • r>1 ,\..,,_ { - ... .;.. ' . " ' " -~· ... ·...... : ...... ,, -., ~.:..,~z'P'i•*~~·4·,;&.~.l~.;;J1;t:,:..;4;;;.,,>;;"-',--A<;;:,.,:,,;,:.\'.;ii;;.•-1:iclc:;p~f1#:4~;...ski#ti""e6·t9M&~li,rs;\Mi~~:_

A'. M. A. ARCHffl:.S OF INDUSTRIAL HE.41.TH

might well have been seen on one examina- ·_ le,iel. This radiation was distributed over tion and o,·erlooked on the i1ext. .. the whole body. . ( No cataracts rleveloped following thc ex- l ' Comment posures. Previous imestigators 3 applying local Mr. L. E. Bird ;u1d other members of L:iroln Laboratory were responsible for the exposi,· ,_. and microwave irradiation to. the eyes of rabbits care of the a,umals. have reported the threshold dose for cata­ 2 243 Charles St. ( 14). racts to be in the range of 120-220 mw/cm. • Our finding that ultra-high-frequency radia­ REFERENCES tion at an intensity of 60 mw/cm.2 is not _cataractogenic is consistent with this, but I. Rirha~dson, A. W.; Duane, T. D., and l lines, H. M.: Experimental Lenticular Opacitie,. Pro- further-l'o~i1i1a.rison.is.pr.oba.bly-un,varrai1ted. - di1ced·b:i,·Microwave-·Jrradiati_ons,-Arch.-P·hy,- :Med: in view of the different frequencies used. _29:765, 1948; A.'M.A. Arch. Ophth: 45-:3R 1951: However, one might ~xpe~t· that the- cata­ r. DaiJ5,; L., Jr:; _'Wakim, K. G. ;· HerrirJ, J. P., ractogenic dose would be · higher with and Parkhill, E. M.: Effects of Microwa, c Dia­ ultra-high:frequency radiation than with thenny on Eye," Am. J. Physiol. i55 :432, J

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