The Rontgen rays in the diagnosis of diseases of the chest. / by Hugh Walsham and G. Harrison Orton.

  • Walsham, Hugh.
Date:
1906
Catalogue details

Licence: In copyright

Credit: The Rontgen rays in the diagnosis of diseases of the chest. / by Hugh Walsham and G. Harrison Orton. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    by hand at the same time on the glass, which can afterwards be transferred to tracing-paper. Another piece of apparatus is that known as the orthodiagraph. With this instrument, by a sj^stem of articulated levers, the tube is made to follow exactly and easily the movements of the pencil which has previously been fixed opposite the anticathode. There are several models of this apparatus, which is used chiefly by German workers; Fig. 14 is perhaps the best form, and can be used both in the horizontal and vertical positions. A glance at Fig. 15 will explain the principle which underlies them all. A D D F G H H' i * 1 I BE E' Fig. 15. A is the bar supporting focus tube ; B is the bar supporting the pencil ; C, the bar connecting A and B ; D, the anticathode ; E, the pencil fixed opposite D ; F G, the object to be measured. The ray of “ normal incidence,” D H (see also A M, Fig. 12), touches the left border of F G, and projects this spot on H, which is then marked with pencil E. D is now moved to D', so that the normal ray D' H' touches the right border of F G at G, and projects this spot on H'. which is marked by the pencil E'. The image FI H' is equal to F G. The line on which H and H' are marked by E represents, of course, the glass or paper on which the tracing is being made. Stereoscopic radiography, by enabling us to obtain the third dimension in space, is in some cases of great service (see Plate I.). The method is simple, and can be carried out by means of a couch with a canvas top, with the tube either above or below the patient. It necessitates the use of two plates for each examination— an additional expense, which, when such large plates have to be employed, is against its general adoption in hospital work. Moreover, in the great majority of cases it is not needed for diagnosis. The procedure is as follows: The patient is placed on the