X-ray diagnostic apparatus with an automatic exposure timer

#The present invention relates to an X-ray diagnostic installation which includes an automatic exposure timer.

#An X-ray diagnostic installation is currently known which is constituted of a portable X-ray generator and a cassette drawer within which an X-ray film cassette is insertable, and which is placed below the patient. As viewed in the ray direction, in back of the X-ray film there is located the measuring probe of an automatic exposure timer in this cassette drawer. This measuring probe may be positioned in conformance with the desired measuring area. The X-ray generator contains a light visor which facilitates the X-radiation to be so focused whereby only the X-ray film is struck by X-radiation.

#In the known X-ray diagnostic installation it is disadvantageous in that the positioning of the measuring probe is difficult inasmuch as its location is not ascertainable from the exterior and, consequently, cannot be adjusted from exteriorly in conformance with the desired measuring area. The positioning of the measuring probe in the known X-ray diagnostic installation is carried out with an opened cassette drawer. The measuring probe is thereby maintained in its present position by means of an adhesive magnet.

#Further advantages and details of the invention may now be ascertained from the following description of an exemplary embodiment thereof, taken in conjunction with the accompanying drawings; in which:

#FIG. 1 is a schematic representation of an X-ray diagnostic installation which is constructed pursuant to the invention;

#FIG. 1a shows a detail of the installation of FIG. 1;

#In FIG. 1 there is illustrated a housing within which there is located an X-ray tube 2. The X-radiation passes through a shutter or diaphragm housing 3 in which there is located a primary X-ray focusing diaphragm which facilitates the focusing of a rectangularly-shaped area. Of the primary X-ray focusing diaphragm, visible are the aperture plates 4. The X-radiation passes through a patient 5 who is lying on a patient support pallet 6. Arranged between the patient 5 and the support pallet 6 is a cassette drawer 7, in which there is located an X-ray film cassette 8. The cassette drawer 7 further contains the measuring probe 9 of an automatic exposure timer which is a component of an X-ray generator 10 supplying the X-ray tube 2.

#The measuring probe 9 detects the ray dosage and, together with the automatic exposure timer, effects the switching off of the X-ray tube 2 pursuant to a predetermined dosage corresponding to an optimum film darkening. An X-ray apparatus which includes an automatic exposure timer is described, for example, in U.S. Pat. No. 2,929,000.

#A light source 11 is located in the diaphragm housing 3, which beams on the patient 5, by means of an optical system 12 and a mirror 13, through the outlet aperture 14 of the diaphragm housing 3. The reproduced rectangularly-shaped area 15 according to FIG. 2 is hereby identical with the ray area which has been focused during the preparation of an X-ray tube, and may be correlated with the cassette 8 by means of the primary ray focusing diaphragm 4. The light visor which is constituted of components 11 through 13, in a known manner, thus facilitates an exact setting of the primary ray focusing diaphragm.