Any and varied instruments have been devised to permit the rapid changing of films or cassettes for special procedures in roentgen diagnosis, particularly in the field of angiography. One of the most commonly used types of apparatus for this purpose embodies a magazine loaded with a roll of film; the latter is moved rapidly between intensifying screens. The device will permit two exposures per second. Each year has brought forth several such pieces of apparatus, attesting to the fact that none available on the market are entirely satisfactory. Since such devices are expensive and as presently constructed are very limited in their utility, they are not commonly found outside of large institutions. The use of roll film for conventional x-ray examinations has had very little experimentation. At one time x-ray paper of 14 × 17-inch size was prepared on a roll for the rapid radiography of the chest, as a survey procedure, but this has largely been superseded by photofluorography. In the latter, roll film has been utilized. The economy of time in the radiography of large numbers of individuals, which is attained by the use of a continuous strip of film, is one of the major benefits accomplished by photofluorography. A rapid film-changing unit, utilizing a continuous roll of film, which would permit as many as five exposures per second, when necessary, and yet would be useful for general conventional radiography would seem to be a highly desirable development. The equipment available at present is not suitable for several reasons. First, it is made only in one size; secondly, and more important, it is extremely difficult and cumbersome to interrupt the procedure before the entire roll is exposed. For the past year or more Robert Sardeson and Karl Kallenberg of the Pako Corporation, of Minneapolis, at the suggestion of and with the co-operation of the Department of Radiology of the University of Minnesota, have been working to devise a unit which will overcome many of the difficulties now affecting rapid film-changing mechanisms, in order to permit their use in general routine radiography. Such a unit should supplant the cumbersome, expensive, time-consuming procedure of making each x-ray exposure on a separate cassette—in fact, it should supplant the cassette entirely wherever there is a reasonably substantial volume of radiographic work. The unit utilizes roll film which is advanced through a pair of intensifying screens at a maximum speed of five films per second. As each succeeding film is advanced into the exposure area, the previously exposed film is cut off by a motordriven knife, so timed that its action will occur as the screens come into contact for the following exposure. The cut film is then transported to a receiving magazine as the next frame is being brought into the exposure area.
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Sep 1, 1956
C C Cole + 1
