9 p.  Reprinted from: Archives of Dermatology and Syphilology, Vol. 9, No. 6, June 192

Kingery, Lyle B.

University of Oregon Scholars' Bank

Precision in Dermatologic RoentgenTherapyTHE VALUE OF RECENT REFINEMENTS IN APPARATUS:PRELIMINARY REPORTLYLE B. KINGERY, M.D.PORTLAND, ORE,Reprinted from the Archives of Dermatology and SyphilologyJune, 1924, Vol. 9, pp. 738-745COPYRIGHT, 1924AMERICAN MEDICAL ASSOCIATIONFIVE HUNDRED AND THIRTY-FIVE NORTH DEARBORN STREETCHICAGOPRECISION IN DERMATOLOGIC ROENTGENTHERAPYTHE VALUE OF RECENT REFINEMENTS IN APPARATUS:PRELIMINARY REPORT *LYLE B. K1NGERY, M.D.PORTLAND, ORE,Ever since the experimental therapeutic use of the roentgen ray wasstimulated by the recognition of its occasional accidental, associatedaction on cutaneous structures, the medical press has constantly con-tained a generous literature describing the therapeutic value of the agentand the proper methods of its application. For many years there werealmost as many technics of application and measurement as there wereoperators, with the result that the popularity of the agent was as fluc-tuating as were the results obtained from its usage. As is the historywith many discoveries, out of the confusion that first clouds true valuesthere emerged a general principle which, if conscientiously adhered toand tempered by judgment and experience, brought about a fair per-centage of favorable results. Thus, while indefinite in many respects,the so-called fractional method of treatment for many years was therecognized technic. Briefly, this method was one by which maximumeffects were gradually obtained by the administration of small doses,repeated at short intervals, and continued over a long period of time.Somewhat later, results favorably comparable to the foregoing wereobtained by adherence to a principle differing radically from the pre-ceding. By the later method, the maximum effect of the rays wasobtained at one sitting and the dose not repeated for an extended period.To this technic the term "massive dosage" has been given. With thisgrowing tendency toward larger dosage, an increasing demand forgreater accuracy of estimation arose. It would now seem one has athis disposal a method meeting these requirements—that of MacKee'smathematical estimation of roentgen-ray dosage. In spite of this epoch-marking work, one still hears voiced by others, or meets in his ownexperience, an occasional variation in expected clinical results, for whichmathematical factors cannot be called to account.Heretofore, such variable factors as tissue tolerance, individual sus-ceptibility, age, complexion, and especially idiosyncrasy, have been theexplanations offered for the foregoing variations. However, treatmentgoverned by the application of available and established facts hasapparently fairly satisfactorily overcome most of these influences.* From the Department of Dermatology and Syphilology, University ofOregon Medical School.2Regarding the exact status and definite influence of idiosyncrasy, theliterature of those most experienced in the work reveals a significantvariance of opinion. With the- development of the new short-raytherapy, special apparatus, theoretically more accurate, has become avail-able. Incidental to the use of this apparatus, possible mechanicalinaccuracies of previous apparatus have been revealed, over whichmathematical formulas have no control. It is on the possible influenceof such a factor that the present study has been undertaken.During the practical and scientific investigations following Roent-gen's original communication, an increasing interest centered about thedevelopment of new exciting apparatus and instruments of precisionor of measurement. As a result of this work, it was the custom for anumber of years to estimate the quantity of radiation affecting a giventissue mass by establishing various so-called constants. These includedmilliamperage, spark gap, number of interruptions per second, distancefrom anode to skin, etc. Before the present degree of perfection wasattained in tubes and transformers, this was a difficult and even haz-ardous procedure ; so much so in fact that a feeling of dissatisfactionexisted generally. With Kienbock's work establishing the law that"the degree of reaction depends upon the quantity of X-ray absorbedby the skin," and later a law stating that "the intensity of the rays variesinversely as the square of the distance," the so-called direct method ofmeasurement of quantity was developed. This was accompanied byHolzknecht's announcement of the chrornoradiometer in 1902. Theoriginal instrument was not a success, and was soon withdrawn fromthe market. The principle, however, modified by various workers andapplied to different instruments still exists as the direct method ofdosage measurement, applied by either the photographic or chemicalmethod.Parallel with, and even preceding, this progress, there developed aso-called indirect method of measurement. As before mentioned, thisestimation depended for its accuracy on the factors of voltage, milli-amperage, time and distance. In the beginning it proved so unreliablethat it soon gave way to the direct technic. With the advent of theinterrupterless transformer and the Coolidge tube, however, the prac-ticability and flexibility of the method rapidly became so evident that itsoon reached, and has since maintained, an application perhaps moreuniversal than that of the method by which it was formerly replaced.With a proper appreciation and a practical method of simple arith-metical computation, it appeared that little was left to be desired,providing the foregoing factors of milliamperage, voltage, time anddistance were always and invariably to be relied on as constants duringany given operation. Naturally, the possibility of variation in thefactors of time and distance is obviated. In the past, fluctuations in3clinical results seemed more easily explained on the basis of individualvariation rather than by any possible change in the value of factors ofmilliamperage and voltage. Regarding the former, one has only towatch the dial of the meter in many cases to see how rarely it is at rest;while up to the present the estimation of voltage has seemed satisfac-Fig. 1.—Left, erythema dose, spark gap estimation; right, erythema dose,sphere gap estimation. These reactions developed simultaneously and remainedpractically equivalent throughout the period of treatment.torily accomplished by the point spark gap. An investigation of therecognized standard requirements for this instrument is of interest.It is to be noted that it should be equipped with needle points; thatthese should be changed after each spark over ; and that they shouldbe approximated in a very definite manner. Finally, it is also to be4noted that even under such conditions the readings may be influencedby temperature, humidity, altitude and surrounding objects. Further-more, given the standard conditions, it seems to be the consensus oftechnical opinion that the reliability of the instrument is subject toserious question above a potential of 50,000 volts. It is thus to be seenthat the instrument on the ordinary machine falls far short of theserequirements ; that there may well be wide variations in machines of thesame and different manufacutres. In proof of such theoretical con-siderations, Ullmann,' using the ordinary point gap., was able to showkilovolt fluctuations as high as 30 per cent., occurring with equivalentfactors, but applied to different machines. If such voltage variationsare possible with the point gap, it seems not unusual that unexpectedclinical results may well occur with an explanation of voltage fluctua-tion as applicable as those hitherto offered.As a result of this lack of uniformity in testing results from variouslaboratories, and a growing realization of the possible causes of errorin the point gap method of estimation, especially with high voltages,electrical engineers have rather recently developed an instrument knownas the sphere gap. This likewise is required to meet certain standardsof construction, but apparently these standards are fairly easily satisfied,even under conditions of office or institutional practice. In addition,the corona discharge, and the influence of humidity, altitude, etc., appar-ently objections to the point gap, are to a large extent avoided. Inother words, theoretically,at least, the sphere gap would seem to be aninstrument available for practical purposes and capable of giving usaccurate information regarding one of the dosage factors which are soessential to constant clinical results. In addition, the fluctuations in themilliamperage may now be satisfactorily controlled by the so-calledstabilizer. With these two improvements at our disposal, it wouldappear that previous possible variations in dosage factors were, to alarge extent, eliminated, and that by their usage more constant clinicalresults might be predicted and obtained.For this preliminary work, twenty-six persons have been used, theexposures being made purely experimentally, and not for the treatmentof any existent disease condition. These persons were chosen at randomfrom dispensary material, without reference to age, sex, complexion,etc. In other words, an attempt was made to imitate an ordinary office1. Ullmann, H. J.: Am, J. Roentgenol. 8:195; American Institute of Elec-trical Engineers Standard, 1922, pp. 20 to 23. Farnsworth, F. W., and Fortescue,C. L.: The Sphere Gap, Tr. A. I. E. E. 32:733 to 737, Pt. 1. Chubb, W. L., andFortescue, C. L.: Tr. A. I. E. E., 32, Pt. 1. Peek, F. W.; Skinner, C. E.; Sands-ford, Jr., J. A.; Steinmetz, C. P., and Others: Discussions, Tr. A. I. E. E. 32,Pt. 1. Peek, F. W.: Dielectric Phenomena in High Voltage Engineering, pp.87 to 116.Fig. 2BFig. 2.—Left, er y thema dose, spark gap estimation ; right, erythema dose,sphere gap estimation.	 J. eight days following exposure. Note absence ofreaction on left.	 1?, slight reaction on left after fourteen days. Present ateight days on right.6or dispensary practice, and at the same time to provide opportunity forinfluence of individual variation. For the most part, each personreceived multiple exposures, with two sets of factors : 6sp 28 :j a 3t and6si) 4ma 1%t. In every instance the stabilizer was used. All exposures8dwere made in parallel, and so far as possible all conditions wereidentical, except that of voltage estimation. In one series the pointgap was used, in the other the equivalent kilovoltage as measured bythe sphere gap. The patients were observed usually at from three tofour day intervals. Because of the outstanding features, and becausethe work is still tinder progress, the results only at certain intervals areincluded.The intervals arbitrarily chosen for observation were the seven andeight day period and the fourteen day period ; that is, the presence orabsence of definite color change at these intervals following exposureformed the basis of the readings enumerated below. This, in the firstplace, excluded the complications of the early so-called "electric reac-tion" sometimes observed, and at the same time excluded those reactionsdelayed longer than the usual time between exposure and physicalresponse. No case was included in one group or the other unless adefinite color change was present. If the presence of such a changewas still questionable at the tenth day, but present at the fourteenth, theresult was included in the latter group.Observed with these points in mind, it was found that certain casesreacted definitely at the end of one or both intervals following exposure.These were clear-cut reactions and were classed as positives. Thesecond group of cases, as would be expected, reacted doubtfully at theend of the first period, but these cases were easily classed as definitereactions at the fourteenth day. The third group were indefinitethroughout, and so far as clinical results might be concerned, wereconsidered negative. Finally, some developed only the faintest possiblechange at the fourteenth day. Adhering to these criteria, it was foundthat out of the total, or twenty-six cases, receiving an erythema (loseas estimated by the point gap, only twenty-one, or approximately 81per cent., presented the expected clinical reaction at the end of the usualseven to ten day period. Following this group through, one case thathad only the faintest suggestion previously, at the fourteenth daypresented sufficient color change, making a total of 22 or 85 per cent.In addition, however, an interesting occurrence became manifest in thatone of the patients who had a strongly positive reaction at the seventhday, at the end of the fourteenth day presented a distinct dermatitis.The fact that this occurred, in spite of personal supervision and everyprecaution, is at least suggestive of certain possibilities. The remain-ing four cases, incidentally of various ages, showed no visible color7change throughout the period of observation. In other words, theexpected clinical results were obtained in only 85 per cent, of the casestreated, in spite of most conscientious attention to the factors on whichthe dosage was based.Passing to the reactions resulting from the use of the sphere gap,it was found that observation during the seven to ten day periodrevealed twenty-four, or 93 per cent., who presented definite reactions.The remaining two were suggestive, but could not be included, althoughfour days later one of these assumed the appearance of a definiteerythema. In other words, the percentage of positive results resultingFig. 3.—Left, erythema dose, sphere gap estimation; right, erythema dose,spark gap estimation. Note absence of reaction on right fourteen days afterexposure, while definite reaction is present on the leftfrom the use of the 'sphere gap at the end of the fourteenth day was96. What would seem to be even more important, however, was thatthe type of reaction was decidedly more constant, better defined, andsubject to much less question than the varying degrees observed in theformer cases. The accompanying Figures 1, 2 and 3 show some of thevariations observed. In brief, then, it was found, under the conditionsof the foregoing experiment, that certain variations are possible, eventhough the factors on which we are accustomed to depend were asconstant as personal care could make them. Further, while neithermethod is without fluctuation, the use of the sphere gap apparentlymakes possible a decidedly higher percentage of positive experimental8clinical results and a gratifying steadiness. While a similar series ofclinical experiments on various apparatus might well not give parallelresults, the laboratory findings of Ullmann and the clinical findingsherein given, indicative of the possible advantage of the sphere gap inits relation to clinical effects, make for its more universal application.By such universal application, the present objections to certain methodsmight well be obviated, and a country wide standardization of technicmade possible. The lack of such a standardization unfortunately hasseriously handicapped the progress of an agent which has, and still does,receive much undeserved criticism, but to which is due an unquestionedplace in modern therapeutics.SUMMARY AND COMMENTIt may be seen that the alternating periods of optimism and pessi-mism through which the roentgen ray has passed have been largelyclue to the relative accuracy of particular methods of control in vogueat a given time. In the beginning, there was the rational theory thatthe extent of the biologic effects of this unusual form of energy shouldbe, predicted by a proper estimation of certain factors. Because ofmechanical imperfections, the method was for a time replaced byphbtographic and chemical procedures. It was soon found, however,that even this method required a personal expertness in the judgmentof rather fleeting color changes, which made the method practicableonly for those with a properly directed and unusual experience. Withgreater perfection in apparatus, the older method again assumed theplace of choice. Depending, as it does, on the factors of milliamperage,voltage, distance and time, and based on the knowledge that these maybe mathematically computed, it leaves little to be desired and findseasy and practical application in the ordinary busy routine. An explana-tion of many of the present variations and disappointing results, itwould seem, must be sought rather in mechanical details of constructionthan in present methods of dosage estimation. In the foregoing, it ishoped one important source of such errors is established, and a practicalmethod of its elimination suggested.CONCLUSIONSI. Under the conditions of the foregoing experiment, variations involtage estimation may, and do, occur, of sufficient magnitude to causecorresponding variations in clinical reactions,2. The possibility of variations such as the foregoing is apparentlylessened by kilovolt estimation, using the sphere gap.3. -The foregoing method of kilovolt estimation applied to formulasherein discussed is suggested as a step toward a more satisfactorystandardization in our present technic.

Precision in Dermatologic Roentgen Therapy

https://scholarsbank.uoregon.edu/xmlui/bitstream/1794/5494/1/mscr_2_Precision_in_dermatologic_roentgen_therapy.pdf

Precision in Dermatologic Roentgen Therapy

Abstract

Similar works

Full text

Available Versions

University of Oregon Scholars' Bank