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Claims  |
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We claim:
1. In a lithotripter having a source for emitting a shockwave pulse and
means for focussing the shockwave pulse along a central axis, said
lithotripter including first and second ultrasonic transmission and
reception means being arranged on the focussing means in a fixed spatial
relationship, the improvements comprising both ultrasonic transmission and
reception means being constructed as sector scanners having scanning
planes, said scanning planes describing a prescribed angle with one
another and proceeding through the central axis, and mounting means for
supporting the first and second ultrasonic transmission and reception
means for movement around the central axis, said mounting means including
displacement means for moving the means for focussing along the central
axis with movement of at least a portion of each of said first and second
ultrasonic transmission and reception means, said mounting means providing
means to enable swivelling of the means for focussing and said portions of
the first and second ultrasound transmission and reception means around a
swivel axis extending perpendicular to the central axis and lying in the
same plane as the scanning plane of the second ultrasonic transmission and
reception means.
2. In a lithotripter according to claim 1, wherein the angle between the
two scanning planes is 90.degree..
3. In a lithotripter according to claim 1, wherein the focussing means is a
lens on which said portion of both of the ultrasound transmission and
reception means are secured.
4. In a lithotripter according to claim 1, wherein the mounting means
includes a member having an opening covered by a coupling membrane and
said mounting means mounts the focussing means adjacent to said coupling
membrane.
5. In a lithotripter according to claim 4, wherein the mounting means
comprises a housing having a first sub-housing including the member with
the coupling membrane and a second sub-housing supporting the shockwave
source.
6. In a lithotripter according to claim 5, wherein both sub-housings are
mounted for rotatable relationship to one another by means of a
cylindrical bearing.
7. In a lithotripter according to claim 6, wherein the second sub-housing
has a non-pivotable first part forming a portion of the cylindrical
bearing with the first sub-housing and a second part mounted for pivotable
movement on said swivel axis relative to the first part, said second part
having a base on which the shockwave source is mounted and said first and
second parts being interconnected by a bellows.
8. In a lithotripter according to claim 7, wherein said bellows forms a
liquid-tight connection between said first and second parts so that the
first and second sub-housing form a liquid-tight chamber for receiving a
liquid dielectric.
9. In a lithotripter according to claim 7, wherein the displacement means
for the focussing means is mounted on the second part of the second
sub-housing.
10. In a lithotripter according to claim 9, wherein the displacement means
comprises threaded members.
11. In a lithotripter according to claim 1, which includes means for an
equiphase ultrasound image registration and shockwave triggering.
12. In a lithotripter according to claim 11, wherein the means for
equiphase ultrasound image registration and shockwave triggering includes
means for sensing patient conditions, selected from respiration states and
ECG.
13. In a lithotripter according to claim 12, wherein the means for
equiphase ultrasound image registration and shockwave triggering includes
a common triggering mechanism for actuating the ultrasound image
registration, as well as the shockwave triggering at a respectively same
respiratory position.
14. In a lithotripter according to claim 1, wherein the portions of the
ultrasound transmission and reception means are positioned on an edge of
the focussing means.
15. In a lithotripter having a housing, means for generating a shockwave
pulse mounted on said housing, means for focussing the shockwave pulse
along a central axis, a first and second means for ultrasound transmission
and reception being mounted in said housing with portions on the focussing
means in a fixed, spatial relationship, the improvement comprising both
the first and second means for ultrasound transmission and reception being
constructed as sector scanners having scan planes describing a prescribed
angle with one another and proceeding through the central axis, said
housing having a first sub-housing and a second sub-housing, said second
sub-housing having first and second parts, said first part of the second
sub-housing and said first sub-housing forming a cylindrical bearing to
enable rotation of the second sub-housing around the central axis relative
to the first sub-housing, said second part mounted for pivotal movement in
the first part around a pivot axis extending perpendicular to the central
axis, said means for generating a shockwave pulse being mounted on the
second part, mounting means for mounting the focussing means on said
second part for movement therewith and the scan plane of the second means
being in the same plane as the pivot axis, said mounting means including
means for displacing the focussing means and at least an ultrasound head
of each of said first and second means along the central axis so that the
focus point for the shockwave is positioned on a stone by first rotating
the second sub-housing until the scan plane of the first means coincides
with the stone to be located, then pivoting the second part to move the
second scan plane to lie on said stone and subsequently displacing the
focussing means to move the focus point for the shockwaves to lie on the
stone.
16. In a lithotripter according to claim 15, wherein the first sub-housing
has an opening covered by a coupling membrane and said means for mounting
the focussing means positions the focussing means adjacent said membrane.
17. In a lithotripter according to claim 16, wherein the first and second
parts of the second sub-housing are interconnected by a bellows to provide
a fluid-tight chamber formed by the first and second sub-housings for
receiving a coupling fluid.
18. In a lithotripter having shockwave means for emitting a shockwave pulse
and means for focussing the shockwave pulse along a central axis, said
lithotripter including first and second means for ultrasonic transmission
and reception being arranged on the focussing means in a fixed spatial
relationship, the improvements comprising said focussing means being a
lens, both the first and second means being constructed as sector scanners
with a scanner head and scanning plane, at least said scanner heads being
mounted on the lens with the scanning planes describing a prescribed angle
with one another and proceeding through the central axis, and mounting
means for supporting the lens and the scanning head of the first and
second means for movement around the central axis, said mounting means
including displacement means for moving the lens with the scanner heads
along the central axis relative to the shockwave means, said mounting
means providing means to enable swivelling of the second means around a
swivel axis extending perpendicular to the central axis and lying in the
plane of the scanning plane of the second means. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention is directed to a lithotripter or lithotripsy device
comprising a focussing means for a shockwave pulse emitted along a central
axis, said lithotripter having first and second ultrasound transmission
and reception apparatuses, which are arranged adjacent a focussing means
in a fixed, three-dimensional relationship to aid in positioning the
calculi or stone to be disintegrated.
A lithotripter is disclosed in German publication No. 27 22 252. This
publication discloses a device having a reflector in the form of a
ellipsoid, which is provided as focussing means. Two ultrasound
transducers are secured to the housing wall of the reflector. The
ultrasound transducers are adjusted so that they intersect the second
focal point of the ellipsoid at an angle of about 30.degree.. The calculus
or stone is identified according to the A-image method. In the exemplary
embodiment described in the German application, the patient is arranged in
a water bath so that displacement of the lithotripter does not involve any
problems when coupling the shockwaves to the patient.
The situation is different when the lithotripter is coupled to the patient
via a membrane and what is referred to as a "dry coupling", such as
disclosed in U.S. Pat. No. 4,674,505, whose disclosure is incorporated by
reference thereto and which patent claims priority from German Patent
Application No. 33 28 051. When utilizing a "dry coupling", care must be
exercised to see that the coupling membrane lies against the patient
optimally unmodified during the locating procedure. Moreover, no
difficulties should occur at a lithotripter when locating calculi in a
complicated position, as can occur to a particular degree given, for
example, gall stones.
U.S. Pat. No. 4,669,483, whose disclosure is incorporated by reference and
which claims priority from German Patent Application No. 34 27 001,
discloses a locating and positioning apparatus which works with an
ultrasound resonator guided by a cardanic suspension. A three-dimensional
spatial locating can be carried out here only with considerable outlay for
the apparatus.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a lithotripter of the
above-known types, wherein complicated calculi positions can also be
reliably spatially located without the condition and position of the
coupling membrane at the patient having to be modified.
This object is inventively achieved in a lithotripter having a focussing
means for a shockwave pulse emitted along a central axis, a first and a
second ultrasonic transmission and reception means for locating the
calculi being arranged in a fixed spatial relationship relative to the
focussing means. The improvements are that the ultrasound transmission and
reception means are constructed as sector scanners whose scanning planes
describe a prescribed angle relative to one another and proceed through
the central axis, that the first ultrasound transmission and reception
means is rotatable around the central axis, and the second ultrasound
transmission and reception means is movable therewith, said focussing
means being mounted by means for displacement along the central axis and
with said displacement means moving both the first and second ultrasonic
transmission and reception means.
A particular advantage of the improvement lies in the ease in which the
apparatus can be manipulated when locating a calculus, particularly a gall
stone.
Other advantages and features of the invention will readily be apparent
from the following description of the preferred embodiments, the drawings
and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view through a lithotripter of the present
invention having a focussing means and two ultrasound sector scanner
means;
FIG. 2 is a diagrammatic presentation illustrating the step of bringing the
first scan plane into congruence with a calculus or stone;
FIG. 3a is a diagrammatic cross sectional view along the first scanning
plane showing the position of the second scanning plane relative to the
calculi;
FIG. 3b is a diagrammatic view of the image on the picture screen for the
second scanning plane;
FIG. 4a is a diagrammatic view showing tilting on a tilting axis to locate
the second plane on the calculi;
FIG. 4b is the image on the screen for the first scanning plane;
FIG. 4c is the image on the screen for the second scanning plane; and
FIG. 5 is a schematic diagram of the triggering system for both the
scanning means and the shockwave transducer for the lithotripter in
accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The principles of the present invention are particularly useful when
incorporated in a lithotripter, generally indicated at 1 in FIG. 1. The
lithotripter 1 is composed of a first sub-housing 3 and a second
sub-housing 5, which are essentially rotationally symmetrical. The
sub-housing 3 has an upper domed part 3a with a central opening 7, which
is covered by a coupling membrane 9, which is over the opening. Shockwave
pulses generated in the lithotripter 1 will emerge through this opening 7
via the coupling membrane 9 into a patient 11, which is to be treated. A
lower, essentially annular part 3b of the first sub-housing 3, is
rotatably connected to the second sub-housing 5 by a plain cylindrical
bearing 13.
The second sub-housing 5 includes a non-pivotable upper or first part 15,
which is fashioned as an annular member and whose outside surface is
received by the part 3b to form the cylindrical bearing 13. The
sub-housing 5 has a pivotable pot-shaped or second part 17, whose floor or
base has an opening 18 on which a shockwave source 19 is secured. The
shockwave source 19 can, preferably, be a shockwave tube, which is
disclosed in greater detail in U.S. Pat. No. 4,674,505.
The pivotable pot-shaped part 17 is pivotably mounted to tilt around a
swivel axis 21 by a pair of trunnions 22 which, as illustrated, lie in the
plane of the paper in FIG. 1. The exact arrangement of the swivel axis 21
shall be set forth in greater detail hereinafter. In order to achieve a
water-tightness of the lithotripter housing 3 and 5, the pivotable
pot-shaped part 17 and the non-pivotable part 15 are interconnected to one
another by an inwardly situated bellows 23. Given a pivot of the
pot-shaped part 17, one half of the bellows 23 will be compressed, while
the other half is pulled or stretched apart. A filling of the housing
parts 3 and 5 with a dielectric, such as, for example, water, is required
for reasons of the shockwave propagation.
The shockwave source 19 has a central axis Z, which coincides with the
central axis of a focussing means 25, which is mounted in the housing
parts 3 and 5 adjacent the membrane 9. The focussing means 25, as
illustrated in the exemplary embodiment, is a biconcave lens. The
convergent lens of the focussing means is arranged centrally relative to
the central axis Z and is mounted for displacement along the central axis
Z by displacement means 29. To this end, the displacement means comprises,
for example, three rotating rods 31 (only one being shown for purposes of
illustration in FIG. 1) having threads, which rods are offset by an angle
of 120.degree. relative to one another. The threads are cut into the upper
part of the revolving rod 31, which is received in a lower part 31a of the
revolving rod 31. The lower rod 31a is mounted in the floor or base of the
part 17 in a rotationally movable fashion. Two respective locking rings 30
hold every rod 31 axially rigid with respect to the part 17. To provide a
seal for the rod, an O-ring 32 is situated in an annular channel which is
formed in the part 31a between the locking rings 30.
The edges of the revolving threads 31 engage into the inside threads at an
outer edge 27 of the lens or focussing means 25. A uniform rotation of the
three revolving threads 31 displaces the lens 25 along the central axis Z
and, thus, perpendicular to the shockwave emission surface formed by the
membrane 9. A gear wheel 34 is mounted on the ends of each of the three
thread parts 31a to create this linear displacement. All three gear wheels
34 are driven by a common tooth belt (not shown), which is driven by a
motor (not shown).
The lens 25 has a focal point F, which, thus, remains on the central axis Z
during displacement.
The heads 33a and 35a of the two ultrasound transmission and reception
means 33 and 35, respectively, are fashioned as sector scanners and are
arranged on the edge 27 of the lens 25 with a relative offset to one
another by a rigidly prescribed angle alpha with respect to the axis Z. In
the illustrated embodiment, the angle alpha amounts to 90.degree.. The
first head 33a is shown in broken lines, since it is situated in front of
the plane of the observation with respect to the cross section of FIG. 1.
The scanning plane E1 of the first ultrasound transmission and reception
apparatus 33 extends perpendicular to the plane of the paper and proceeds
through the central axis Z.
The second scan plane E2, which is produced by the second sector scanner or
head 35a of the second ultrasound transmission and reception means lies in
the plane of the paper and is illustrated by lines including dashes and
three dots. The second scan plane E2 also extends through the axis Z. The
geometrical conditions for the scan planes E1 and E2, which extend
perpendicular to one another and both extend through the central axis Z of
the focussing means 25, are rigidly prescribed. The ultrasonic heads 33a
and 33b are illustrated as being inclined towards the focal point F and
are accommodated in the periphery or at the edge 27 of the lens 25 and
are, thus, firmly mounted therein.
Three or four reinforcements or bulges 37 (only one is shown) are provided
on the part 3b of the first sub-housing 3. Each of these bulges has a bore
39, which receives rods or members of a mounting means, which enable the
lithotripter 1 to be moved into and out of engagement with the patient 11.
The process or method of locating the lithotripter 1 is illustrated in
FIGS. 2-5. FIG. 2 illustrates a schematic plan view of the effective
focussing means 25, as well as the first sector scanner 33a with its first
scan plane E1 in the plane X-Z, and the second scanner head 35a with its
second scan plane E2, which is in the plane Y-Z. In order to pivot the
second scan plane E2 around the swivel axis 21 of FIG. 1, the Y axis is
provided with a symbolic swivel bearing 41. The sector-shaped scan planes
E1 and E2 can be viewed on a picture screen of the apparatus 33 or 35.
In broken lines, FIG. 2 shows a constellation of the axis X', Y' and Z',
wherein Z' is identical to Z of the lithotripter 1 relative to a calculus
K in the inside of the patient 11, as initially randomly derived when the
lithotripter is coupled to the patient still undirected when first
applied. The calculus or stone K lies at some location between the scan
planes E1' and E2', which are not yet aligned.
As a first step for the exact location of the stone K in a lithotripter
adjustment, the second sub-housing 5 is rotated around the central axis Z
with the assistance of the cylindrical bearing 13 upon entrainment of both
the apparatuses 33 and 35 until the calculus or stone K appears in the
first scan plane E1 of the first ultrasonic scanner head 33. This
corresponds to a solid line X, Y axis in FIG. 2. For the sake of clarity,
the apparatus 33 and 35 are shown outside of the lens 25, however, in the
present case, the overall arrangement of the lens 25, with the heads 35a
and 33a are all rotated together.
With the stone or calculus K lying in the plane E1, the apparatus will have
the configuration or cross section illustrated in FIG. 3a. The picture
screen image of the calculus K and the mixed-in focus F occurs, as
illustrated in FIG. 3b. However, the scan plane E2, which in FIG. 3a
extends perpendicular to the plane of the paper through the axis Z, still
misses the calculus or stone K. The picture screen for the second sector
scanner 35, thus, does not yet show the calculus K.
As illustrated in FIG. 4a, the next step is to pivot the shockwave source
19 and focussing means 25, plus the rigidly connected ultrasound
transmission and reception apparatuses 33 and 35 around the swivel axis
21, which extends perpendicular to the plane of the paper from the
position illustrated in broken lines to a position where the calculus K
will lie in the plane E2 and will appear in the picture screen of the
second sector scanner 35.
The swivel axis 21 is aligned so that the calculus or stone K
simultaneously remains in the scan region of the first ultrasonic scanner
33a. This means that the axis 21 must be arranged to extend perpendicular
to the central axis Z and must also lie in the scan plane E2 of the second
ultrasonic scanner head 35a, which is imaged as lying in the back side of
the focussing means 25.
FIG. 4b is the image for the first sector scanner 33 with the position of
the calculus K shown in broken lines before the pivoting and the position
after pivoting is shown in bold lines. In FIG. 4c, the image for the
sector scanner 35 illustrating the position of the calculi after the
pivoting so that the calculi also lies in the plane E2. After the second
positioning step, which is the step of pivoting on the axis 21, the
lithotripter 1 is aligned so that the calculus or stone K lies on the
central axis Z and, thus, can be seen on both picture screens.
The depth position of the calculus K on the central axis Z, however, has
not coincided with the focal point F of the focussing means 25. The focal
point F is now displaced towards the calculus K in a third adjustment step
by turning the rotating threads or positioners 31 of the displacement
means 29. The focussing procedure is, thus, concluded and the first
shockwave pulses can now be triggered to disintegrate the stone K.
The displaceability of the focal point F, without having to modify the
position of the coupling membrane 9 relative to the patient 11 is an
advantage of the lithotripter of the present invention. The possibility of
turning and/or swivelling the scanning planes E1 and E2 of the ultrasound
scanners 33 and 35, respectively, creates the possibility of undertaking a
reliable positioning, even given complicated calculus positions, which
occurs particularly with gall stones.
The reliability to treatment is, thus guaranteed.
In the above description, it is assumed that the calculus was in a fixed
position. However, movement of the stone will occur because of breathing
activities, and this movement is a continual appearance and disappearance
in the two ultrasound images. The same, to a lesser degree, will also
occur due to the heart activity. It is, therefore, advantageous when the
registration of the ultrasound image respectively occurs in the same
respiration and/or each ECG position at which the shockwave is likewise to
be triggered. It is just as advantageous for the evaluation carried out by
the attending physician when only these ultrasound images are displayed.
In FIG. 5, a common trigger mechanism or means 50 is provided for this
purpose. This trigger mechanism is used both during the registration for
the ultrasound images, as well as when triggering the shockwaves. To this
end, a pickup or sensor 55 for the respiration and a pickup or sensor 57
for the heart activity (ECG) are arranged on the patient 11, who is
positioned on a patient supporting plate 51. As illustrated, the plate 51
has an opening 53, through which the lithotripter extends to apply the
shockwaves to the patient. The output signal of the sensors 55 and 57 are
supplied to correspondingly known evaluation devices or means 59 and 61,
respectively. The output signals of these evaluation devices or means are
conducted in common to a trigger mechanism 50 in the present installation.
It is adequate in many uses to only provide the one sensor 55 with its
evaluation means or device 59 for supervising respiration and to omit the
sensor, such as 57, and its evaluation means 61 for heart activity.
In a known way, the trigger mechanism 50 forms a trigger signal t from the
supplied signals, and this trigger signal t is then supplied via a
selective switch 63, either to a trigger mechanism or starting means 65
for the shockwaves, or to an exposure starting means 67 for the ultrasound
images. In the illustrated switch position, the shockwave supply or
generator means 69, which belongs to the shockwave source 19, is driven
with the trigger signal t. In the present case, the shockwave source 19 is
shown as a known shockwave tube.
In the other non-illustrated position of the switch 63, the trigger signal
t charges the exposure starting means or mechanism 67 for the ultrasound
images of the two ultrasound scanners 33 and 35. The echo signals picked
up by the heads 33a or, respectively, 35a are portrayed on the picture
screens (not shown) with the assistance of the apparatus or means 33 and
35, respectively. According to the arrangement of FIG. 5, the registration
of the two ultrasound images respectively occurs in a respiratory position
in which the shockwave will also be subsequently triggered. As explained,
this can also apply to phase relationship of the heart activity.
Although various minor modifications may be suggested by those versed in
the art, it should be understood that we wish to embody within the scope
of the patent granted hereon all such modifications as reasonably and
properly come within the scope of our contribution to the art.
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