DE3330894A1 - X-ray diagnosis device - Google Patents

Abstract

The invention relates to an X-ray diagnosis device having an image-intensifier television relay link which, for conversion of the X-ray image into a sequence of television signals, contains an arrangement (7) of detectors to be scanned line by line. To achieve sufficient resolution and effective conversion of the X-rays (1.1) with short scanning times, the invention envisages the use of two-dimensional image pick-up arrays (20.0 to 20.6) which are arranged in two rows (22, 23) at intervals from one another, the second row (23) being staggered with respect to the first row (22) and the intervals of the arrays being wide enough for them to be able to receive the inactive zones (21), which enclose the arrays, and that means (10, 11) are provided which direct the scanning of the arrays in such a way that an uninterrupted sequence of television signals which can be reproduced on a monitor (9) is obtained. The invention is suitable in particular for use in X-ray diagnosis (X-ray television). <IMAGE>

Description

X-ray diagnostic facility

The invention relates to an X-ray diagnostic device according to the Preamble of claim 1. Such a device is known from American Journal of Radiology 139: 1045-1050, December 1982, particularly p 1045, penultimate paragraph.

In X-ray diagnostics one is because of the extended possibilities of Image manipulation, especially for improved reproduction of weak contrasts, came to the acquisition of digitized X-ray images. Facilities for this have so far been built with an X-ray image intensifier television system as a radiation detector. Here particularly disturbs the large image fields (thorax 40 x 40 cm) caused by the television chain Restriction of the spatial resolution due to the limited number of lines and bandwidth.

One is therefore the aforementioned in X-ray diagnostic devices Art came to the implementation of the primary image in a television signal sequence by means of to carry out opto-electronic solid-state image converter. In addition to matrices made of photodiodes Charge-coupled (CCD) image converters have recently become increasingly important, for example in the magazine "Electronic Design" from 03/15/1976 to the Pages 70 to 75 are described in detail. Such converters are about in one Diagnostic device according to US-PS 43 65 269 known. The disadvantage here has been proved that today only conversion area of 800 x 800 picture elements ("pixels) available are. However, due to the insufficient number of pixels, such devices also do not show any sufficient spatial resolution.

There are CCD lines with a sufficient number of elements (2000 to 4000), with which an X-ray image, for example from an X-ray screen, an X-ray film or from Output screen of an X-ray image intensifier could be scanned in high resolution. However, this is because of the narrow width (e.g. 25 to 50 µm) of the active surface of the CCD line is ineffective and would, with the normally achievable X-ray output, i.e. a few lOOIuR per second, in the input level of the detector at long sampling times (many seconds) because each of the approximately 2000 to 4000 pixel lines in the scanning direction (i.e. perpendicular to the CCD line) with approx. 15 to 50 / uR must be applied so that the image quality is not limited too much by the quantum noise.

The invention is therefore based on the object of an X-ray diagnostic device of the type mentioned, effective conversion of the X-rays and short scanning times to reach. This object is achieved according to the invention by the features in the characterizing part of the claim 1 resolved.

The invention assumes that you can also use two-dimensional Image acquisition arrays to suffice the image areas can come if you have several CCD matrices are coupled to one another in one direction (x direction, line direction) and scans the x-ray screen image in the direction perpendicular to it (y-direction). Man such a digitizable slot receiving device (see e.g.

~ Radiology "120 (1976) pages 705 to 712, especially 706, fig 2) obtained when the object to be examined is displayed with a correspondingly fan-assisted x-ray beam. It just has to be on it Care should be taken to use multiple CCD matrices, each dead by one Zone (i.e. an inactive area that is necessary for holding and contacting) are surrounded, if possible without visible disturbing transitions in one direction (x-direction) to be lined up and thus a coherent picture, i.e.

a sufficiently high number of picture elements to be obtained in the x-direction.

Further details and advantages are given below with reference to the in The embodiments illustrated in the figures are further explained.

In FIG. 1, one is schematically offset in a diagram arranged image converters as recording devices equipped X-ray diagnostic device -in Figure 2, the offset arrangement of image converters and in FIGS. 3 and 4, optical deflection devices for supplying parts of the image to the staggered image converters.

In FIG. 1, 1 denotes an X-ray tube, which is of a X-ray generator 2 is operated. An X-ray beam produced in this way 1.1 goes from the X-ray tube 1 and penetrates a patient 3, so that on the Entrance luminescent screen of an X-ray image intensifier 4 creates a fluoroscopic image. This is done at the end of the X-ray image intensifier 4 with an optical device 6 occurring output image to a Arrangement 7 opto-electronic Transfer solid-state imager. These image converters can, for example, each consist of a matrix of photodiodes or a CCD image converter (see Fig 2). The television signal sequence obtained from the arrangement 7 is used in a video amplifier 8 processed, amplified and finally fed to a monitor 9.

The scanning of those accommodated in the arrangement 7 offset from one another Image converter is controlled in such a way that the emerging television signal sequence with the Television standard is synchronized, so that a conventional monitor 9 to play back the Television picture can be used.

The arrangement of CCD image converters is shown in FIG. They are labeled 20.0 to 20.6. The converters are 20.1, 20.3 and 20.5 at a distance from one another in a line 22 and the converters 20.0, 20.2, 20.4 and 20.6 in the next line 23 below, offset to a gap. The transducers 20.1 to 20.6 each have 200 x 500 sensitive elements. the Lines 22 and 23 are 5 mm apart, while the transducers in in the same direction have an extension and spacing of 5 mm each. Included come the inactive edges with respect to the creation of television samples 21, which extend in the distances to be so that in the line direction each the active end of one transducer, e.g. 20.1, above the active beginning of the next, is located in the underlying line 23 transducer 20.2. Above that The end of the active part of the transducer 20.2 lies in an analogous manner in the one above it Line 22 the active start of converter 20.3 etc.

The scanning comes at a scanning speed of 1000 mm / sec of the one half line 22 in each case after 10 msec in the other half line 23 'and vice versa. It only has to be ensured that on the arranged in one plane Converter 20.1 to 20.6 the corresponding parts of the output screen of the image intensifier 4 that appear.

This can be done so that by means of the clock generator 10 a Deflection generator 11 (Figure 1) is put into operation, with which a deflection device 15, which is located on the image intensifier 4, is stimulated to generate the output image of the image intensifier 4 to move so that when scanning the first When the end of the first line is reached, the image converter 20.1 has shifted the image so far is that the continuation is in the first line of the converter 20.2, whereupon a Shift back to the first line of converter 20.3 etc. takes place until the end the line 1 of the transducer 20.6 is reached, whereupon the scanning of the second line begins in converter 20.1.

For example, when recording with a slot recording device are useful Get pictures without distraction.

For this purpose, the CCDs 20.1 to 20.6, as shown in FIG. 2, are shown in Lines 22 and 23 are staggered.

The projected in the y-direction indicated by an arrow 24 Edges of respective neighboring elements then just abut one another or are if possible lined up seamlessly. Primary collimator and secondary diaphragm (moving slit) of the Slot receiving devices are - projected towards the X-ray focus - the arrangement from 20.0 to 20.6 similarly divided into correct intervals. Through this Only the active areas from 20.0 to 20.6 are masked out, i.e. the detector areas, irradiated. It is accepted that when scanning in the y-direction 24 respective Neighboring stripe elements are shown somewhat shifted in time. This is like even permitted for other non-distraction arrangements if the speed of movement in the object 3 is small compared to the effective scanning speed, because then no blurring in the figure, i.e.

no motion blurring, become disruptive.

It is also possible to use generators without an electronic deflection device 5 10 and 11 get by when in the beam path of the imaging optics 6 optical means are attached, which the image parts on the staggered image converter conduct. Such a deflection means can, according to FIG. 3, for example be an optical prism 30 as shown in FIG. 3 and denoted by 30. That of one X-ray tube outgoing beam 31, which penetrates a diaphragm 32, is as in FIG. 1, amplified in an image intensifier 4.1 and then reaches the fluorescent exit screen 33. The prism 30 is located there and directs the corresponding image part 34 opposite Figure 35 running straight ahead without prism 30. With a so-called Slot radiography device (X-ray fan beam 31 perpendicular to the plane of the paper) it is sufficient to alternate a piece of the screen 33 with a prism 30 to provide and to leave the following piece free, so that at points 34 and 35 the corresponding transducers of an arrangement 7 can be located. When choosing the prisms 30 one can assume that d = (n - 1) a (for small angles a) d = deflection angle a = vertex angle of the prism n = refractive index of the prism with n = 1.5 obtained one d = 0.5 a.

A deflection angle d of a few degrees is therefore easy to achieve. The dispersion is negligible for a small a.

If this is not the case, the arrangement of the CCDs 20.0 to 20.6 can nevertheless be maintained in the manner shown in FIG. 2, only a strip-shaped fluorescent screen must then be used by deflecting the partial light beam in sections be mapped so that his image is again in the equidistantly interrupted strips of lines 22 and -23 is split.

The image of a strip-shaped screen can be done with a lens 6 are carried out to the light beam emanating from every second screen section bend in such a way that the images alternate on the screen sections 20.1, 20.3 and 20.5 or 20.0, 20.2, 20.4 and 20.6 come. The distraction is done by the placed prisms 30, if the deflection is to take place essentially straight. Instead of a single lens 6, several can be used, when it comes down to it, an image with a higher degree of photometric efficiency to reach.

If you want a figure bent by 900, roughly the total length To shorten the arrangement, according to FIG. 4, a similar effect can also be achieved with mirrors 40 can be achieved. It is only necessary that the respective Row 22 and 23 corresponding mirrors 40 and 41 are inclined differently, so that images 42 and 43 move into line 22 or 23.

The same effect can also be achieved with corresponding prisms with total reflection can be achieved.

The "dead zones" 21 can be on the edges of the phosphor screen sections become small if the deflecting prisms 30 or mirrors 40 are as close as possible to the fluorescent screen of the image intensifier 4 are arranged. At the output screen of the image intensifier It is therefore advantageous to use a fiber optic plate 45 as the output screen carrier use. The deflecting prism can then be attached directly to the exit of this plate will.

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Claims (10)

Claims X-ray diagnostic device with an image intensifier television chain, to convert the X-ray image into a television signal sequence to be scanned line by line Includes detectors optically coupled to the image intensifier output, i a d u r c h e k e n n -z e i c h n e t that the converter of the input image in a television signal sequence has a recording surface made up of several sections is composed, in which the detectors are arranged in arrays in two-dimensional rows are, and that the scanning switching device of the detector arrays in the sense of joining of the rows of the arrays that belong together as parts of a television line is switched. 2. X-ray diagnostic device according to claim 1, d a -d u r c h g Note that the arrays are spaced at least two rows apart are arranged from each other, with the second row opposite to the first on gap and the distances are at least wide enough to accommodate the inactive zones which enclose the arrays. 3. X-ray diagnostic device according to claim 1, d a -d u r c h g It is not noted that the detector arrays act as sensors, so-called CCDs (Charge coupled devices) included. 4. X-ray diagnostic device according to claim 2, d a -d u r c h g I do not know that when using an electronic vacuum image intensifier an image shifting device is assigned to this as the image input, which shifts the image sideways by one line between the first and the second scan, and that the reproduction device contains means for combining the two scanning results in the sense of achieving closed lines. 5. X-ray diagnostic device according to claim 4, d a -d u r c h g It is not noted that the images are shifted optically. 6. X-ray diagnostic device according to claim 5, d a -d u r c h g I do not know that a strip-shaped luminescent screen is cut through in sections Deflect the partial light bundle is imaged so that its image in two equidistant interrupted strip is split up, which then reproduces a closed one Allow row. 7. X-ray diagnostic device according to claim 5, d a -d u r c h g e k e n n n n e i n e t that the optical image of a strip-shaped screen takes place with an objective and that proceeding from every second screen section Light bundle is optically kinked, using thin prisms as kink means so that two lines can be scanned, which is then a gapless one Allow illustration. 8. X-ray diagnostic device according to claim 7, d a -d u r c h g It is not noted that there is a bend of 900, including deflection prisms with total reflection or mirrors are used. 9. Diagnostic device according to claim 7, d a d u r c h g e k e n It should be noted that the optical deflection means are as close as possible to the luminescent screen are arranged, the carrier is preferably a fiber optic disk. 10. Diagnostic device according to claim 9, d a -d u r c h g e k e n n n z e i c h n e t that a deflection prism is attached directly to the object to be imaged.