File:Archives of physical medicine and rehabilitation (1920) (14754828094).jpg

Identifier: archivesofphysic04ameruoft (find matches)
Title: Archives of physical medicine and rehabilitation
Year: 1920 (1920s)
Authors: American Academy of Physical Medicine and Rehabilitation American College of Radiology and Physiotherapy American Congress of Physical Medicine and Rehabilitation Radiological Society of North America
Subjects: Physical therapy
Publisher: (Chicago, etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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is notoften that we find it necessary to usethis ray to a greater degree than about52.5 degrees from the central beam. We have made a rather careful studyof the distribution of rays from the tar-gets of six tubes and from this in-vestigation I am convinced that the in-tensity of the radiation 65 degrees fromthe central ray of the average Coolidgetube is not materially less than that at20 degrees from the central ray or atthe central ray itself. The one factorwhich seems to alter the distributionof the ray from the surface of the targetas reported by Dr. Coolidge, and itcan readily be understood by all of us,is the character of the pitting of thetarget, and we can readily understandhow the target may be so deeply pittedthat there may be an appreciable varia-tion in the amount of radiation over thearea illustrated by Figure 1, and sincethe appearance of the target will notgive us a very definite idea as to thealteration of this distribution of ray itis at once apparent that the mere me-
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245 chanical setting of the target for se-curing the radiation of two patients atone time is not a scientific process, andtherefore the setting of the position ofthe tube must be accomplished by theaid of some method of measuring theradiation. The author has employed the ioniza-tion process by the use of electroscopesand also the galvanometer as describedby Duane, and I believe the Duaneprocess to be most suitable for the useof roentgenologists. A method may be adopted to treattwo patients from one tube, utilizing aleaning wall. In this there is the sug- DEPARTMEXT OF TECHNIQUE gestion to the patient of being undersomething which may fall, and it doesnot permit of such perfect ventilation ofthe treatment room nor is it so con-venient for making measurements ofradiation as the perpendicular wall,particularly if water phantoms are used.Figure 4 illustrates the authors owninstallation and is shown particularly toindicate those important things whichthe operator is able to observe fromone

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