X-ray Apparatus For Screening And Radiographs In Two Directions

Abstract

X-ray apparatus including a first X-ray tube and associated image intensifier for mylographic examination to which a second X-ray tube and the associated image intensifier are detachably coupled; X-ray beams from the two X-ray tubes are alignable to traverse the patient-supporting table, and movable lengthwise and laterally relative to a patient.

Description

The invention relates to an X-ray apparatus for fluorescopic examination, or screening, and making radiographs in two orthogonal directions; the apparatus comprises a first image intensifier secured to a frame of an X-ray beam centering device and aligned with a first X-ray source. A carriage movable on the frame has an upright column releasably secured thereto, and an image intensifier and an additional X-ray source for lateral screening or fluorescopic examination provided to be displaceable together with the centering apparatus in the direction of length of the table.

Such apparatus are particularly suitable for use in myolography, i.e. for visual inspection by X-ray reproduction of the vertebral column channel of the human body. The contrast to be reproduced radiographically is obtained by means of liquid (positive) or gaseous (negative) contrast means. These contrast agents are usually introduced into the lower part of the vertebral column channel and their course in said channel is followed on a display screen. Since liquid contrast agents tend to accumulate always at the lowest point in the verte bral column channel, this channel can be screened or visually inspected in two directions in a satisfactory manner only when the patient does not move. The patient has therefore to be subjected to penetration of X-rays simultaneously or alternately from one side and from the front or the rear side. When gaseous contrast agents are employed, only fairly weak contrasts are obtained and therefore the geometric lack of sharpness has to be minimized. This requires use of a radiographic cassette in the examinations or the screen has to be disposed near the object, which is not readily possible in known apparatus. If liquid contrast agents absorbable by the body are employed, a rapid examination is required, since these agents spread through the body within a short period of time. Liquid contrast agents not absorbed by the body, for example "Pantopaque" have to be removed from the channel after the examination, the removal being constantly checked. Therefore the vertebral column of the patient has to be accessible from the outside during X-ray examination. Moreover, the apparatus should preferably not be restricted solely to examinations in two directions, as in the case of myolographic examinations. For this purpose the additional x-ray tube and the associated image intensifier required for lateral x-ray observation have to be removable in a simple manner from the apparatus.

An X-ray apparatus according to the invention is intended to further satisfy the above requirements, and is characterized in that the image intensifier for lateral screening is detachably coupled with a vertically displaceable frame coupled with a carriage of the x-ray centering apparatus the additional X-ray source can be detachably secured to the tower of the centering apparatus, to the centering apparatus itself, or to a holder rigidly secured to the centering apparatus. This apparatus permits arranging the cassette of the fluorescent screen comparatively near the patient, while the vertebral column is readily accessible for the examination.

The invention will be described more fully hereinafter with reference to an embodiment shown in the drawing.

FIG. 1 shows a known apparatus for myolographic examination.

FIG. 2 shows diagrammatically an apparatus in accordance with the invention and

FIG. 3 shows a coupling for the lateral X-ray source in accordance with the invention.

The apparatus shown in FIG. 1 comprises a patient table 1, with an X-ray source 3 arranged beneath the top plate of the table. An image of the object produced by the X-ray source 3 is projected onto the screen of an image intensifier 6, attached to a x-ray centering apparatus 5. This apparatus is adapted to be displaced laterally upwards, or downwards (in the vertical direction) as well as at right angles to the plane of the drawing. A further X-ray source 7 and the associated image intensifier 8 are fastened laterally beneath the centering apparatus. The connections thereof with the display apparatus are detachable.

Central rays from the X-ray sources 3 and 7 intersect each other at a point 9, which is located in the apparatus at a fixed distance from the input screen of the image intensifiers 6 and 8. The distance of the point of intersection 9 from the display screen of the image intensifier 6 is comparatively large in order to allow a downward movement of the lateral image intensifier 8 together with the associated X-ray source 7 without the centering apparatus 5 touching the patient 4, when the point of intersection of the central beam has to be displaced downwards to near the table top 2. For the same reason the point of intersection 9 of the central beam has to be at a comparatively large distance from the display screen of the lateral image intensifier 8. Therefore the geometric fading determined by the finite dimensions of the focus of the X-ray tube is in both directions comparatively great.

For reducing the geometric fading in this case it is not possible to arrange the centering apparatus 5 near the patient and then screen only in the vertical directions; the horizontal lateral central beam would then be at a very low level, even beneath the table top 2, after which the centering apparatus could be moved upwards for examination in the horizontal direction, but usually there is no time available for such an examination.

In an X-ray apparatus according to the invention, as is shown in FIG. 2, the sighting or X-ray centering frame 11 is connected via an angular member 12 with a turret or column 13, which is fastened to a longitudinally movable carriage 14 of the centering apparatus, said carriage holding the X-ray source 15. The X-ray source 15 is centered to an image intensifier 10, arranged on the centering frame 11.

The centering frame is adapted to be displaced in the carriage 14 within a given range in the direction of length of the table top - and in a transversely movable carriage (not shown) - in a direction transverse of the table top; moreover, the centering apparatus is movable in the vertical direction, the connecting member 12 being guided in guide rails 31 of the column 13.

The lateral image intensifier 17 is mounted on a frame 18, which is coupled with the longitudinally movable carriage 14 of the centering apparatus so that it is movable together with the centering apparatus in the direction of length. The frame 18 may be readily disconnected from said carriage so that the apparatus may also be used for examinations from one direction. The image intensifier is journalled in a rotary collar 19, which is held by guides 20 (for example bars), in FIG. 2 only one bar is visible, the other is covered by the image intensifier 17, said guides being displaceable in a guide frame 21. The guide frame 21 is held by the frame 18 and is displaceable along it in a direction of height. The lateral image intensifier is therefore movable as follows:

By means of the bars 20 the rotary collar 19 or the image intensifier 17 can be displaced laterally so that the distance of the input screen of the image intensifier from the center of the table may be varied between 240 mm. and 400 mms. The guide frame 21 can be displaced together with the image intensifier 17 upwards or downwards so that the axis of the image intensifier may lie at a distance from 50 mms. and 250 mms. above the table. For this purpose a supporting ring 16 is used, which terminates the bars 20 and serves in addition as a stop for the lateral displacement. During the pivotal movement of the table top around a horizontal axis, the image intensifier maintains a fixed direction relative to the horizontal. This means that the position of the patient is determined by the position of the centering apparatus associated with the image intensifier 17 so that the examination is considerably simplified.

If desired, a supporting device for radiographic cassettes and fine rasters may be provided for the image intensifier so that radiographs can be made.

A diaphragm cassette 22 of the X-ray source 27 is provided with two transverse projections (FIG. 3) adapted to slide along rails 24, 25, fastened to the or column 13 of the sighting apparatus. Between the rails a recess 26 is provided through which the X-rays can pass through the column. The column and the connecting piece 12 are provided with notched clamping frames 28 and 29 respectively, into which can snap a stop lever 30, provided on the depth diaphragm and indicated in FIG. 3 by broken lines. The stop lever can be changed over so that the X-ray source can be coupled either with the connecting member and hence with the centering frame or with the column of the centering apparatus, the distance of the axis of the image intensifier from the table or from the centering frame then depending upon the notch in the frames 28 and 29 into which the stop lever 30 is inserted.

When the X-ray source is coupled with the column of the centering apparatus, its distance from the table top is fixed and the image intensifier can then be accurately centered to the central beam. The image intensifier 10 for vertical screening of the centering frame 11 can then be displaced in the vertical direction without affecting the position of the lateral central beam. The lateral image intensifier may be moved towards or away from the patient without resulting in a change of the position of the image intensifier 10. The two image intensifiers can thus be arranged near the patient so that only a slight geometric fading need be accepted. A further advantage of this construction resides in that at a movement of the centering frame in the vertical direction only the mass of the vertical screening apparatus has to be moved, whereas the mass of the horizontal screening apparatus remains stationary.

If required, the image intensifier 10 may be moved completely upwards and, after removal of a pawl, within the horizontal arm of the connecting member 12 to the right into a non-use position. In this way it is possible to carry out treatments of the patient while checking in the horizontal direction. If a vertical screening check is desired, the lateral image intensifier may be shifted downwards so that the patient is readily accessible from that side.

If with a diaphragm adjustment of the lateral X-ray beam, the course of a contrast agent through a strongly curved vertebral column has to be observed, the lateral image intensifier is effectively coupled with the clamping frame 29 and the centering apparatus so that by displacement of the centering apparatus in the vertical direction it can follow the spine. Since the diaphragm beam is very narrow, the fact that the axis of the image intensifier is then not always accurately centered to the central beam can hardly be disturbing. The risk of radiation passing alongside the lateral image intensifier may, however, by avoided by adjusting the lateral image intensifier to an average working height.

For examinations where a high working speed is not required a single image intensifier is sufficient. For this purpose the image intensifier is fastened by a detachable quick release at will to the sighting apparatus 11 or to the guide frame 18, 21 so that the examinations can be carried out one after the other in both directions.

Claims

I claim:

1. In an X-ray apparatus for fluorescopic examination of a patient positioned longitudinally on a supporting table, the apparatus including a base, a frame, a first image intensifier supported in a generally vertical orientation on the frame, a carriage displaceable on the base longitudinally relative to said patient, a first X-ray source carried by the carriage and alignable with said first intensifier, the apparatus further comprising an upright column extending from said carriage and means for releasably connecting the column to the frame, a second image intensifier detachably secured to said carriage, and second X-ray source detachably secured to said upright column and alignable with said second intensifier, the second X-ray source providing a laterally oriented X-ray beam for penetrating the patient.

2. Apparatus according to claim 1 wherein said second image intensifier and X-ray source have a central axis generally normal to that of the first intensifier and X-ray source.

3. Apparatus according to claim 1 further comprising guide means secured between said carriage and the second image intensifier for permitting movement of said second intensifier axially and horizontally relative to the corresponding second X-ray source.

4. In an x-ray apparatus for fluorescopic examination of a patient positioned on a supporting table, the apparatus described with respect to a horizontal-longitudinal axis of the table and a vertical axis, the apparatus including a frame, a first image intensifier, for vertical-axis examination, supported by the frame, a carriage movable lengthwise relative to said table, a first X-ray source supported by the carriage and for alignment with the first image intensifier, an upright column extending from the carriage, said frame adjustably secured to the column, a second image intensifier, for horizontal-axis examination, detachably secured to said carriage, and a second X-ray source detachably secured to said column.