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| United States Patent | 4829986 |
| Link to this page | http://www.wikipatents.com/4829986.html |
| Inventor(s) | Eichler; Juergen (Nuremberg, DE);
Grasser; Franz (Eggolsheim, DE);
Oppelt; Sylvester (Bamberg, DE) |
| Abstract | A lithotripsy work station for disintegrating a calculus in a patient has a
patient support table on which the patient is disposed, a drive unit for
selectively positioning the table, a shock wave generator, an x-ray system
for generating a three dimensional visual representation of at least the
region of the patient in which the calculus is disposed. The location of
the focus of the shock wave generator is known with respect to the x-ray
representation. A mark generator generates at least one mark superimposed
on the x-ray representation, and also generates a signal which is supplied
to the drive unit which causes the drive unit to position the table based
on the position of the mark on the x-ray representation with respect to
the position of the focus. A mark positioner is also provided for manually
positioning the mark on the x-ray representation in coincidence with the
calculus, so that the table is moved to a position with the patient
thereon such that the focus coincides with the calculus for effective
disintegration or shattering thereof. |
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Title Information  |
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Drawing from US Patent 4829986 |
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Lithotripsy work station |
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| Publication Date |
May 16, 1989 |
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| Filing Date |
July 13, 1987 |
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| Priority Data |
Aug 22, 1986[DE]3628502 |
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Title Information |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a lithotripsy work station, and in
particular to such a work station having a three-dimensionally adjustable
patient support table, a drive unit for moving the table, a shock wave
generator for disintegrating calculi in a patient, and an x-ray
examination means for locating the calculi within the patient and an image
intensifier video chain for generating a visual image of the region of the
patient in which the calculus is disposed.
2. Description of the Prior Art
A lithotripsy work station is disclosed in German Utility Model
Registration No. 85 28 785 having two shock wave generators which can be
swiveled from a standby position to an operating position. For locating
the calculus to be disintegrated, the work station is equipped with an
x-ray diagnostics system having two x-ray sources which generate
respective intersecting x-ray beams. Each x-ray beam is converted into a
visually displayable image by respective image intensifier video chains.
The two x-ray beams intersect an an isocenter at which the shock wave
generators are focussed when in the operating position.
When the calculus, for example a kidney stone or a gallstone, is recognized
by the x-ray examination system, the calculus is brought to the isocenter,
and thus to the focus of the shock wave generators, by displacing the
patient support table. This is generally undertaken in the
transillumination mode, thus exposing the patient to an undesireably high
radiation dose.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a lithotripsy work
station of the type described above which permits the patient support
table to be displaced by means of stored x-ray exposures so as to bring
the calculus to be treated into the focus of the shcok wave generator
without unnecessarily exposing the patient to high radiation doses.
The above object is achieved in accordance with the principles of the
present invention in a lithotripsy work station wherein a mark generator
is provided for mixing a mark into each of the image intensifier vide
chains. The mark corresponds to a spatial point above the patient support
table, and a mark positioner is also provided so that the position of the
mark on each of the video displays can be manually adjusted. The mark
generator is also connected to the drive unit for the patient support
table for providing a signal thereto so as to move the table to a working
position wherein the spatial point is in the focus of the shock wave
generator. The position of the focus of the shock wave generator with
respect to each of the x-ray image displays is known, and the mark is
manually positioned to be coincident with the image of the calculus on the
x-ray image. The positon of the mark, and thus the position of the
calculus, with respect to the known position of the focus is then known,
and the patient support table is positioned accordingly.
Two x-ray images obtained in different planes can be stored at a beginning
of the treatment, and a displaceable mark can be superimposed on the
monitor for each image. Positioning of the mark, and thus positioning of
the patient support table, can then be undertaken based on the stored
images, without continually exposing the patient to radiation.
The working position which has been determined in this manner can then be
again achieved at any subsequent time without further transillumination of
the patient in an embodiment wherein the mark generator includes a memory
for the coordinates of the working position. A high resolution x-ray
exposure for documenting the intermediate status of the calculus, such as
when an initial shock treatment is to be followed by subsequent shock
treatments, can be moved in an embodiment of the work staion from a
standby position to an exposure position under the patient support table.
After the exposure has been made, the cassette holder can be moved back to
the standby positon, and the patient support table can be automatically
returned to the stored working position. The x-ray exposure cassette can
thus be moved to its optimum exposure position without being disturbed by
the shcok wave generator or the image intensifier, and after the exposure
has been made, the patient support table can be returned to the working
position for further treatment, if necessary.
DESCRIPTION OF THE DRAWINGS
The single FIGURE is a schematic block diagram of a lithotripsy work
station constructed in accordance with the principles of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The lithotripsy work station shown in the drawing includes an x-ray
diagnostics system having two x-ray sources 1 and 2 which generate
respective x-ray beams which penetrate a patient 4 situated on a patient
support table 3. At least one shock wave generator 5 and two x-ray image
intensifiers 6 and 7 are arranged beneath the patient support table 3. The
x-ray source 1 and the x-ray image intensifier 7 may be arranged such that
a central ray of the x-ray beam from the x-ray source 1 is perpendicularly
incident on the patient 4 (a.p. projection). The x-ray source 2 and the
x-ray image intensifier 6 may be arranged obliquely with respect to the
first central ray such that the central ray from the x-ray source 2
intersects the central ray of the x-ray tube 1 at the isocenter inside the
patient 4 at an angle .alpha. of, for example, 45.degree. (c.c.
projection). Transillumination images are thus obtained from two different
projection directions, so that the patient can be three-dimensionally
shifted by means of the patient support table 3 to position an object 22
within the patient, for example a kidney stone or a gallstone, at the
isocenter, and thus in the focus of the shock wave generator 5.
An opening 25 is provided in the patient support table 3, and the shock
wave generator 5 can be swiveled from a standby position 5a shown in
dashed lines to the operating position shown in solid lines in the drawing
through this opening. When in the operating position, the focus of the
shock wave generator 5 is directed at the isocenter, so that shock wave
treatment can be undertaken in the operating position, and the object 22
can be disintegrated.
Video cameras 8 and 9 are respectively coupled to the x-ray image
intensifiers 6 and 7, the outputs of which are respectively entered in two
image memories 10 and 11. Respective output signals from the image
memories 10 and 11 are supplied to inputs of respective addition stages 12
and 13, the outputs of which are supplied to respective monitors 14 and 15
for visual reproduction of the x-ray images.
After transillumination of the patient, or at least a region thereof
wherein the object 22 is situated, has been undertaken using the x-ray
sources 1 and 2, the x-ray images are converted into video signals which
are stored in the image memories 10 and 11.
The patient support table 3 is three-dimensionally positionable (as
indicated by the three axes) by a drive unit 16 which controls the
operation of respective motors (not shown). The drive unit 6 also controls
positioning of an x-ray exposure means, for example, a cassette holder 17,
also disposed beneath the patient support table 3. The cassette holder 17
can be moved from the standby position shown in solid lines in the drawing
to an exposure position indicated by dashed lines by operation of the
drive unit 16. The drive unit 16 had an operating console 18 for entering
the required functions. For example, the patient support table 3 may be
three-dimensionally displaced by actuating an adjustment control 20, and
the current position of the patient support table 3 can be seen on the
operating console 18 by display means 21 for the three spatial coordinates
x, y and z.
A mark generator 19 is also connected to the drive unit 16, as well as to
respective inputs of the addition stages 12 and 13. The mark generator 19
generates a mark 28 which is mixed into each of the video change so as to
be superimposed on the x-ray images on the monitors 14 and 15. The mark 28
can be positioned on each of the displays by a mark positioner 23. For
example, the mark 28 can be displaced on the image on the monitor 15 by
the positioner 23 so that identification of the object 22 in the
x-direction and y-direction (horizontal directions) is determined.
Subsequently, the apparatus is switched so that the mark 28 on the monitor
14 can be positioned to be coincident with the image of the object 22, so
that the position of the object in the z-direction (vertical direction)
can be identified. When the marks 28 have been brought into coincidence
with the image of the object 22 on each screen, the current coordinates of
the marks 28 are stored in a memory 24 which may, for example, be
contained within the mark generator 19. The position of the isocenter
(illustrated by a graticule) with respect to each of the display images is
known, so that the distance of the mark 28 from the isocenter can be
calculated, and a signal corresponding to this distance can be generated
and stored. By actuating a trigger knob 26 on the operating console 18,
the patient support table 3 is then displaced by the drive unit 16 on the
basis of a signal provided by the mark generator 19 so that the object 22
is situated at the isocenter, and thus at the focus of the shock wave
generator 5. At the same time, the coordinates of this position of the
patient support table 3 are entered in the memory 24 as the working
position.
The mark positioner 23 may consist of a so-called track ball or "mouse."
The mark positioner 23, however, may alternatively be a light cursor,
respective potentiometers allocated to the three spatial coordinates, or a
resistance film.
After shock wave treatment has been undertaken, an x-ray exposure can be
made for intermediate supervision of the treatment, or for documenting the
final patient status. The patient support table 3 can then be moved from
the working position by actuating the trigger knob 27, so that the
cassette holder 17 can be displaced from the illustrated standby position
to the exposure position beneath the patient 4. The x-ray source 1 is then
triggered to make the exposure. The cassette holder 17 is then returned to
the standby position and the patient support table 3 is returned to the
working position on the basis of the coordinates stored in the memory 24,
so that the shock wave treatment can be continued as needed. The
lithotripsy work station disclosed herein thus permits the radiation load
on the patient to be maintained at a low level, because adjustment of the
patient support table need not be undertaken while the patient is
undergoing continuous transillumination.
Although modifications and changes may be suggested by those skilled in the
art it is the intention of the inventors to embody within the patent
warranted hereon all changes and modifications as reasonably and properly
come within the scope of their contribution to the art.
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Description |
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