. The principles and practice of roentgenological technique . y light transmitted from whitebackground. A neutral tinted standard isplaced in the left hand frame between the eyeand pastille for studying the efl:ects of smalldoses so as to increase the accuracy of readingwhen daylight is used. Bordier. In this form of measuring device, five stand-ard tints are provided. To make the compari-son easier, the pastilles are square and are in-serted into a rectangular opening in the stand-ard tints. HohkuccJit radiometer (Fig. 149) The index is a tinted celluloid band. Thereaction pastilles are a pla
. The principles and practice of roentgenological technique . y light transmitted from whitebackground. A neutral tinted standard isplaced in the left hand frame between the eyeand pastille for studying the efl:ects of smalldoses so as to increase the accuracy of readingwhen daylight is used. Bordier. In this form of measuring device, five stand-ard tints are provided. To make the compari-son easier, the pastilles are square and are in-serted into a rectangular opening in the stand-ard tints. HohkuccJit radiometer (Fig. 149) The index is a tinted celluloid band. Thereaction pastilles are a platino-barium cya-nide compound 5 millimeters in diameter. Theestimation is made by placing an unexposedhalf pastille under the colored celluloid band injuxtaposition to the half pastille which hasbeen exposed to the x-ray. Both these halfpastilles are moved up and down until the halfdiscolored by exposure matches the tint of theimexposed half moving under the colored cel-luloid. The instrument is calibrated for fourvarieties of pastilles. 108 HAMPSONS METHOD. Fig. 149.—Holzknecht radiometer. C. Sc. reddishbrown color band, under which a semi-circularpiece of screen, carried on Sk. St. is exposed pastille is carried on R. St., moveson Schl. but under a clear piece of is moved until both semi-circles forma circle of the same color. Then the scalewhich is indicated automatically is read in thenotch of the R. St. The other scales arefor pastille pieces which have a slightly differentinitial tint. of Sabouraud and Noire radiometer. The Hunits are accurate only when a medium ray isemployed. The biological effects of- tintB, (S and N) are different from 5 H becausethe S and N scale is calibrated for harder usually required about 9 H of a harder rayto produce the same skin results as are ob-tained with 6 H and a softer ray.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradiogr, bookyear1920
