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We claim as our invention:
1. A medical examination system, comprising a computer tomography apparatus
(1, 3) for producing transverse layer images; positioning means (4) for
positioning a patient (2) relative to said apparatus (1, 3); a
patient-targeting device (5) for operative association with said
positioning means (4) and adjustable to define a desired path orientation
relative to a patient positioned by said positioning means for the
introduction of an instrument (9) into the patient (2); and a phantom
apparatus (FIG. 4) comprising adjustable simulation parts (12, 13, 15
through 19) for simulating a path in a specified body location, and
providing for orientation of the targeting device by means of the
adjustment of the simulation parts (12, 13, 15 through 19) with the use of
patient transverse layer images produced by said computer tomography
apparatus (1, 3), said simulation parts having mechanically adjustable
marking means mounted thereon for physical adjustment in space to
respective locations in respective layer simulating planes corresponding
to respective locations in the patient transverse layer images, thereby to
define the desired path in space.
2. A medical examination system according to claim 1, characterized in that
said targeting device (5, 5') exhibits a support-mounting (6, 7, 8) for a
biopsy needle (9, 9') which permits a free adjustment of the biopsy needle
(9, 9') in space.
3. A medical examination system according to claim 1, characterized in that
each simulation part (12, 13, 15 through 19) comprises a wheel (12, 13),
and a mark (16, 18), adjustable in the plane of the wheel (12, 13), and
the wheel (12, 13) being adjustably mounted in the direction of its axis.
4. A medical examination system according to claim 1, with said phantom
apparatus further comprising a simulation targeting device (5') with a
simulation instrument (9') and adjustable correspondingly to said
patient-targeting device such that the orientation of the simulation
instrument (9') in the simulation targeting device (5') by means of the
adjustment of the simulation parts (12, 13, 15 through 19) is directly
transferable so as to provide for corresponding orientation of the patient
targeting device (5) to define a desired path orientation for the
introduction of the instrument (9).
5. A medical examination system according to claim 1, with said phantom
apparatus having means (20, 9') for releasably coupling said patient
targeting device (5) in predetermined operative association with said
adjustable simulation parts (12, 13, 15 thorugh 19) such that adjustment
of said simulation parts directly actuates said patient targeting device
to a corresponding orientation while the patient targeting device is
coupled with said simulation parts. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
In modern x-ray diagnostics, computer tomographs are increasingly employed
in which the patient is scanned in a transverse layer by means of a
measuring arrangement comprised of an x-ray source and a radiation
receiver. From the measured values, delivered by the radiation receiver,
which measured values correspond to the attenuation of the x-radiation in
the patient, a computer calculates an image of the scanned transverse
layer. An important field of application of a computer tomograph is the
examination of the cranium; for example, for the detection of tumors. If a
tumor is ascertained in the x-ray image, it is necessary to remove a
tissue specimen from the tumor tissue. The problem which arises here is to
guide a biopsy needle in a directed fashion through a bone gap in the
skull in such a fashion that said needle precisely reaches the location of
the tissue at which a tissue specimen is to be removed.
SUMMARY OF THE INVENTION
The object underlying the invention resides in producing a medical
examination installation which permits examinations to be conducted with
the aid of a computer tomograph and tissue specimens to be removed in a
targeted fashion on the basis of the computer tomography images.
In accordance with the invention, this object is achieved in that the
medical examination installation comprises a computer tomograph for
transverse layer images with patient positioning means, a patient
targeting device with means for introduction into the patient which are
capable of alignment (or orientation) by means of the targeting device,
and a phantom apparatus with adjustable simulation parts for specific body
locations, a simulation-targeting device, capable of alignment (or
orientation) to the simulation parts, or means for connection of the
patient targeting device with the phantom apparatus. In the case of the
inventive examination installation, the patient can be secured in a
nondislocatable fashion into the positioning means. With the aid of the
patient targeting device and a computer tomography image, an adjustment of
the phantom apparatus corresponding to the existing conditions is
possible. The simulation targeting device can then be aligned (or
orientated) to a specific body location and its alignment can be
transmitted to the patient targeting device. However, it is also possible
to align the patient targeting device on the phantom apparatus, to remove
it from this apparatus and to connect it with the positioning means for
the patient, so that only a single targeting device is necessary.
An embodiment of the invention has the feature that every targeting device
exhibits a support-mounting for a biopsy needle which permits a free
adjustment of the biopsy needle in space. In this embodiment, the removal
of tissue specimens, for example from a tumorous tissue, is possible with
the aid of a biopsy needle. It is furthermore advantageous to provide
every simulation part with a mark which is adjustable in a plane of a
wheel, and to adjustably mount the wheel for displacement in the direction
of its axis. Thus, for example, two wheels can be provided on the phantom
apparatus; one in order to simulate the bone gap in the skull of a patient
for the purpose of introducing a biopsy needle, and the other in order to
simulate the plane in which a tissue specimen is to be removed.
The invention shall be explained in greater detail in the following on the
basis of an exemplary embodiment illustrated on the accompanying drawing
sheets; and other objects, features and advantages will be apparent from
this detailed disclosure and from the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a computer tomograph with positioning means and a
patient targeting device of an examination installation in accordance with
the invention;
FIG. 2 illustrates a view of the targeting device according to FIG. 1;
FIG. 3 illustrates the targeting device according to FIGS. 1 and 2 from
above;
FIG. 4 illustrates a phantom apparatus of an examination installation in
accordance with the invention;
FIGS. 5 through 7 illustrate details of the phantom apparatus according to
FIG. 4;
FIGS. 8 through 12 illustrate tomographic images for the purpose of
explaining the adjustment of the targeting device; and
FIGS. 13 through 15 illustrate variants of the positioning means which are
particularly expedient.
DETAILED DESCRIPTION
In FIGS. 1 and 3 a patient support 1 is illustrated on which a support
plate 1a with a patient 2 rests. The head of the patient 2 is fixed (or
positioned) in the opening of a schematically illustrated computer
tomograph 3 with the aid of positioning means 4. The positioning means 4
is provided with screw threaded elements arranged in a ring 4a, which abut
against the head of the patient 2 and hold the latter securely in
position. The ring 4a with a patient targeting device 5 is adjustable in
height relative to the support plate 1a. The patient targeting device 5 is
connected with the positioning means 4 and, according to FIG. 2, exhibits,
on an annular frame 6, a yoke (or cross bar) 7 which bears, in a
longitudinally-displaceable fashion, a holder 8 for a biopsy needle 9. The
biopsy needle 9 is mounted by the holder 8 for pivotal movement about two
axes 10, 1Oa (FIG. 2), which are perpendicular to one another, and is
therefore freely adjustable in space. The holder 8 may be fixed at a
desired position in space by means of set screws such as indicated at 10.
The phantom apparatus according to FIGS. 4 through 7 exhibits, on a base
11, simulation parts for specific body locations which are formed by
wheels 12, 13. The wheels 12, 13 are mounted on a shaft 14. The wheel 12
bears (or supports), according to FIG. 5, a mark 16 which is
longitudinally displaceable on a spoke 15; i.e., which is adjustable in
the plane of wheel 12 along the length of a diameter. Analogously to this,
wheel 13 bears a mark 18, FIG. 6, which is adjustable on a spoke 17 along
the length of a diameter. The mark 18 is formed by a hole (or aperture) in
a plate 19. On the shaft 14 a holder 20 is mounted which bears a targeting
device 5' which corresponds to the targeting device 5 of FIGS. 1 through
3.
For the removal of a tissue specimen by means of the biopsy needle 9, which
is freely adjustable on the targeting device 5, one proceeds in the
following fashion:
The biopsy needle 9 of the targeting device 5 is positioned in its
zero-position in which it lies along the center axis 22 of the targeting
device 5. Subsequently, by means of the computer tomograph 3, which, for
example, can be designed in accordance with the German No. OS 2,438,708, a
photographic exposure of the biopsy needle 9 is prepared which is
illustrated in FIG. 8. The biopsy needle, in this photographic exposure,
marks the reference center 9-1 which is of significance in terms of
further evaluation (or analysis). After this photographic exposure, the
apparatus can no longer be permitted to be displaced.
First the dimension A, FIG. 1, the distance between the reference plane 21
of the targeting device 5 and the bone gap 23 in the skull of the patient
2, is ascertained with the use of the targeting device 5. The dimension A
is adjusted on the phantom apparatus according to FIG. 4 through axial
displacement of the wheel 13 on shaft 14.
Subsequently, a photographic exposure of the bone gap 23 in the head of the
patient 2 is prepared with the computer tomograph 3. This photographic
exposure is illustrated in FIG. 9. It shows the transverse layer of the
head of the patient 2 in which the bone gap 23 lies and shows the location
of the bone gap at 23-1.
The images according to FIGS. 8 and 9 are superimposed and result in an
image according to FIG. 10. From the image according to FIG. 10, the angle
.alpha. and the distance r are ascertained and these values are adjusted
on the wheel 13 with the aid of the mark 18 (FIG. 6).
By means of the computer tomograph apparatus 3, an image is now formed of
that particular transverse layer in which the target point, for example a
tumor, lies. One obtains an image such as shown in FIG. 11. In the case of
this photographic exposure, the value B, namely the distance between the
transverse layer in which the bone gap 23 is disposed, and the transverse
layer in which the target point is disposed, must be read off and adjusted
in the phantom apparatus according to FIG. 4 through axial displacement of
the wheel 12.
If the images according to FIGS. 8 and 11 are superimposed, then the image
according to FIG. 12 is obtained, with imaged points 9-1 and 24. From this
image, the angle .alpha.' and the distance r' are ascertained and the mark
16 of the wheel 12 (FIG. 5) is adjusted corresponding to these values.
The biopsy needle 9' of the phantom apparatus is now so adjusted that it
runs through the mark 18 of the wheel 13 and points to (or aims at) the
mark 16 of the wheel 12.
Two possibilities now arise. In case the targeting devices 5, 5' are two
separate targeting devices, the values adjusted at the targeting device 5'
are transferred to the targeting device 5. Following this transfer, the
biopsy needle 9 has the correct position and its tip is disposed at the
location at which tissue is to be removed. The second possibility is to
provide only a single targeting device and to remove this targeting device
from the phantom apparatus subsequent to adjustment and to connect it with
the positioning device 4. Naturally, the values adjusted on the phantom
apparatus must here be fixed as by tightening of set screws or the like
prior to the transfer.
The positioning means illustrated in FIGS. 13 through 15 exhibit two
bolsters (or cushions) 26, 27, which are interconnected in an articulated
fashion by means of a hinge joint 25. The bolsters 26, 27 are mounted on
rigid base plates and can be pressed against the head of the patient by
means of adjustment screws 28, 29. For the purpose of further positioning,
two clamps 32, 33, which are longitudinally displaceable and arrestable
(or lockable) on guides 30, 31 (FIG. 15) are provided which have
extensions 32a, 33a introduced into the bone gap 23 and braced therein. In
addition, a bolster 35 (FIG. 14) is mounted on a holder 34, which bolster
is introduced into the mouth of the patient and fixed in position in the
upper jaw bone (or superior maxilla). The holder 34 can be displaced
relative to a mounting block 4a and arrested (or locked) in an adjusted
position by means of a set screw 35'.
It will be apparent that many modifications and variations may be effected
without departing from the scope of the novel concepts and teachings of
the present invention.
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