WO2008138962A1

WO2008138962A1 - Miniaturized device

Info

Publication number: WO2008138962A1
Application number: PCT/EP2008/055946
Authority: WO
Inventors: Rainer Kuth; Horst Siebold; Rainer Graumann
Original assignee: Siemens Aktiengesellschaft
Priority date: 2007-05-16
Filing date: 2008-05-15
Publication date: 2008-11-20
Also published as: DE102007023059A1

Abstract

The invention relates to a miniaturized device (1) comprising a probe (5) and a first sensor (S1) which determines a first position information, and a second sensor (S2) which determines a second position information, the first sensor (S1) and the second sensor (S2) being independent from each other.

Description

description

Miniaturized device

The invention relates to a miniaturized device.

Such a miniaturized device is e.g. As a technical endoscope (cavity viewing device) executed and allows, for example, the technical testing of difficult to access cavities or components in engines, machinery and vehicles and aircraft, equipment and structures, without having to perform elaborate disassembly or demolition.

In US 2001/0049497 Al a miniaturized device is known, which is designed as a medical endoscope. The known endoscope is used to treat internal bleeding or to close open cuts in the body of a living organism and is equipped with a clip. The clip has a pair of pliers which is mounted in a guide associated with the medical endoscope. To clamp the internal bleeding or to close the incision, the clip is moved out of the guide of the medical endoscope, wherein after activation of the clip, the tissue enclosed by the forceps clamped and the bleeding is stopped or the incisional wound is closed.

Furthermore, DE 100 12 560 A1 discloses a miniaturized device designed as a robotic endoscope for performing medical endoscopy. The known robot endoscope has a plurality of segments which are interconnected via a flexible link connections. By means of a plurality of flexible linear drive elements, which are mounted obliquely laterally in the circumferential direction around each segment with respect to the longitudinal axis of the robot endoscope and which are pneumatically or hydraulically pressure-driven, the robot endoscope is moved within a human or animal hollow organ. From DE 101 42 253 Cl a miniaturized medical device is known which is designed as a magnetically navigable endoscopy capsule (endorobot). A bar magnet is arranged in the housing of the known endo-robot and interacts with defined magnetic fields from an external magnet coil system, which also includes a magnetic field control system, whereby the endorobot can be navigated in the cavity of a patient. The magnetic force acting on the endorobot depends on the position of the magnetic dipole to the external magnetic field. Only if this is known, the magnetic force can be optimally dosed.

The endo-robot known from DE 101 42 253 C1 can not be held in a predetermined position with the aid of magnetic fields in a freely suspended manner. The reason for this is that according to the Earnshaw Theorem (see Transactions of the Cambridge Philosophical Society, Vol. 7, 1842, pages 97 to 120) any such configuration is unstable in at least one direction. Free-floating is thus never stable, but requires constant stabilization and application of correction forces that can not be applied without knowing the position of the miniaturized medical device (endoscopy capsule, catheter).

The problem described above arises to a particular extent when interventional procedures are to be undertaken with the miniaturized medical device, for example biopsies. In such interventional interventions it is necessary to hold the miniaturized medical device very precisely at a certain position, for which also fine deflections have to be detected exactly.

In EP 1 543 766 A1, a system for the in-vivo position determination of an endoscopy capsule is known, which can also be designed as a magnetically navigable endorobot. In this system, the assignment of an image recording of a capsule-internal camera to the respective spatial position (location and orientation) of the endoscopy capsule or endo-robot during this image acquisition

The system according to EP 1 543 766 A1 comprises a magnetic field generator, which is located outside a body and generates a strongly varying alternating magnetic field in the region in which the endoscopy capsule or the endorobot and moves images (gradient field, Quadrupole field). The frequency of this alternating magnetic field is of the order of a few kHz, so that this alternating field penetrates the human body almost without interference. In order to make the endoscopy capsule or the endorobot nevertheless sensitive to this alternating field, the endoscopy capsule or the endorobot is equipped with a sensor coil which is dimensioned such that the magnetic alternating field is detected by this sensor coil. The sensor coil has five or six degrees of freedom, which are measured as a function of the spatially strongly varying alternating field. The measurement defines the location and the orientation of the capsule-internal sensor coil in the alternating field and thus the position of the endoscopy capsule or the endo-robot relative to the body or relative to the surrounding space.

The unique relationship between the position (location and orientation) of the sensor coil and the anatomy of the patient is established by a conventional registration procedure. The user selects anatomical landmarks (bones, organs) on the patient that are included in the anatomical images of different imaging modalities that support the measurement (for example computed tomography, C-arm,

Ultrasound, magnetic resonance imaging) can also be identified. An external navigation unit computationally links the signal of the capsule-internal sensor coil with the coordinate system defined by the registration. The registration method on which this system is based is relatively complicated because of the necessary anatomical landmarks in the body of the patient. In addition, the theoretical accuracy of the positioning of about 1 mm in a coordinate system defined by the registration is practically impossible to achieve. Practically, only an orienting accuracy (depending on the patient and examination area) of a few centimeters is given because there is a time-dependent deviation between the anatomy at the time of registration and the time of the current sensor coil measurement because of the always given organ movement.

DE 10 2005 032 577 A1 describes a method for determining the position of an endo-robot which can be navigated in a magnetic field which is generated by an external magnet system that can be controlled by a magnetic field control system. The known method comprises the following method steps:

1. specification of a desired value for a movement of the end robot to the magnetic field control system,

2. taking a first image of a target area before moving the end robot,

3. adjustment of the magnetic field by the magnetic field control system, whereby the movement of the end robot is carried out according to the target value,

4. taking a second image of the target area after the movement of the end robot,

5. determination of an actual value for the movement of the end robot from the first and the second image, 6. determination of the deviation of the actual value from a nominal value that can be predetermined by the magnetic field control system,

7. feedback of the deviation to the magnetic field control system,

8. Calculation of an optimized magnetic field from the deviation. This method performs only a relative and thus not very accurate position determination for Endoroboter from two recorded images, namely a first image of a target area before the movement of Endoroboters and a second image of this target area after the movement of Endoroboters.

The RU 2 278 356 Cl provides an arrangement for determining angular positions of moving objects (submarines, ships, aircraft). The known arrangement comprises a 3D magnetometer (magnetic field strength meter) with a magnetic sensor and four 3D accelerometers (accelerometers).

In US 5,237,753 and DE 41 06 932 Al sensors are known with which each of the current angle (inclination) can be measured relative to the direction of gravity.

From WO 2005/120345 A2 a position detection system for capsule endoscopes is known. The position sensing system includes a sensor coil that detects the induced magnetic field generated by a magnetic induction coil. The position detection system further comprises a control coil, by which the magnetization is controlled in an induction coil such that the magnetic field in the operating area from at least three different directions acts on the capsule endoscope.

WO 2006/064972 A1 discloses a position detection system for a capsule endoscope. The position detecting system includes a magnetic induction coil, a control coil generating an alternating magnetic field, magnetic sensors, a frequency detection unit and a position analysis unit.

From EP 1 723 898 A1 a position detecting system for a capsular medical device is known. The capsular medical device comprises a main body insertable into a living body. in the

Main body, a coil (capsule coil) is arranged, which generates a resonant circuit. Arranged around the living body are coils (control coils) which generate an alternating magnetic field and induce a magnetic field in the capsule coil. Further, the position detecting system includes a plurality of coils that detect the magnitude of an induced magnetic field generated in the capsule coil by the control coil. In US 2004/0207389 Al a method for the detection and compensation of eddy currents is known. The method comprises the determination of an undisturbed phase for at least one first and one second position signal, wherein inter alia a ratio between the amplitude of the first position signal at a first frequency and the amplitude of the second position signal at a second frequency is determined. Furthermore, in this method, the relationship between the eddy current phase of the first position signal and the eddy current phase of the second position signal is determined. This method can be used to improve the magnetic location in image-based medical applications, since the position determination determines the eddy current generated by the electrically conductive object.

By the US 6,553,326 Bl a method for detecting errors in a magnetic position determination (location, orientation) of a probe in an external magnetic field is known. The method includes a number of measured values of magnetic field intensity that depend on the location and orientation of a probe inserted in a human body. The position (location, orientation) of the probe is determined from an extremum of an optimization function. The optimization function depends on the differences between the measured magnetic field strength and the magnetic field strength determined from a model. If the determined difference lies within a preselected value range for which a disturbance of the magnetic field is defined, then this disturbance of the magnetic field is eliminated by appropriate measures.

The object of the present invention is to provide a miniaturized device whose probe can be exactly determined in its position.

The object is achieved by a miniaturized device according to claim 1. Advantageous embodiments The invention are each the subject of further claims.

The miniaturized device according to claim 1 comprises a probe and a first sensor, which determines a first position information, and a second sensor, which determines a second position information, wherein the first sensor and the second sensor are independent of each other.

In the miniaturized device according to the invention, a position information can be determined by two independent sensors. From these two independently determined position information then the exact position of the probe can be determined.

The two independent sensors can be arranged spatially at different locations both within the miniaturized device and on the outside or in the outer wall of the miniaturized device, with sensors arranged within the miniaturized device being the preferred variant.

In the context of the invention, the miniaturized device can be, for example, a technical device, for example a technical endoscope, or a medical device, e.g. Endoscope, endoscopy capsule or endorobot, act. An endoscopy capsule is passively, so transported by their ingestion solely because of peristalsis through the gastrointestinal tract. By contrast, an endorobot is a miniaturized medical device that can be actively navigated via an internal magnetic element by means of an external magnetic field. In the present invention, the term "endorobot" is thus understood to mean a magnetic endoscopy capsule, which is also referred to as a magnetic capsule endoscope.

In the miniaturized device, the first position information preferably comprises information about the location of the probe. de (eg in Cartesian coordinates) and the second position information preferably information about the solid angle of the probe (orientation in 3D space). With the location of the probe and the solid angle of the probe at this location, complete information about the position of the probe is available.

Within the scope of the invention, the first sensor and the second sensor can detect according to the same physical principle. Furthermore, the invention also includes embodiments in which the first sensor and the second sensor detect according to different physical principles.

According to a preferred embodiment of the miniaturized device, the first sensor is designed as a 3D Hall sensor and the second sensor as a 3D gravity direction sensor.

In this embodiment of the miniaturized device according to the invention, the 3D Hall sensor (first sensor) measures the flux density of a basic magnetic field which is used to determine, with the known amplitude of the magnetic flux, the location of the probe (first position information) in a cavity (eg in a hollow organ of a mammal or in a cavity of a plant). The 3D gravitational direction sensor (second sensor) measures the direction of gravity relative to an axis fixed to the probe (for example, the longitudinal, transverse or vertical axis), whereby the solid angle of the probe (second position information) can be determined.

The 3D gravitational direction sensor may in this case have various configurations.

Thus, the 3D gravity direction sensor may comprise at least one hollow sphere with a liquid which is freely movable and optically detectable therein and at least one optical detector for detecting the position of the optically detectable liquid. Furthermore, it is possible to execute the 3D gravity direction sensor as an acceleration sensor.

According to a further variant, the 3D gravity direction sensor comprises at least one mechanical element in which a deformation occurs under the influence of gravity, which is detectable.

According to a further advantageous embodiment, the 3D gravity direction sensor calculates its required information from data of an analytical model and / or determines its required information from a punctual detection of amplitude and flux density of a magnetic background field.

According to a further preferred embodiment of the miniaturized device, the first sensor is designed as a 3D Hall sensor and the second sensor as a gyroscope. The arrangement of a gyroscope in a miniaturized medical device, which is preferably designed as an endoscopy capsule or as an endo-robot, is known from DE 10 2005 031 652 A1. With regard to the 3D Hall sensor (first sensor), reference is made to the above statements. Together with the position information provided by the 3D Hall sensor, so that the position can be accurately determined.

The gyroscope provides information about changes in the solid angle of the probe (second position information) in the miniaturized device. Due to the precise positioning of an endoscopy capsule, which is moved solely by the peristalsis, thereby movements in the stomach and intestine or missing movements in the gastrointestinal tract are reliably detected. Thus, for example, diarrhea, constipation, obstruction or obturation can be reliably detected. The information recorded here by the gyroscope can be stored, for example, in at least one device-internal memory unit and / or via at least one device-internal memory unit. ne transmitting unit to a device external evaluation are transmitted.

In the case of an endorobot that can be navigated via an external magnetic field, the rotations or small translations detected by the gyroscope can additionally be used to record the absolute position in the gastrointestinal tract, making it even more precisely possible to correct the position if necessary. In particular, if the endorobot is to be kept free-floating in the external magnetic field without "wobbling", the constant stabilization which requires the application of correction forces can be performed much more accurately.

The information of the gyroscope are thus used to correct the position of the miniaturized medical device. This can be done either in the miniaturized medical device itself, if this has internal options (own drive) for the position correction. Alternatively, the position of the miniaturized medical device can be corrected externally, for example via an external magnetic field generated by a navigation magnet.

Regardless of whether the movement of the miniaturized medical device by the peristalsis of the gastrointestinal tract (endoscopy capsule) or by a manual movement (endoscope) or by a device-internal drive or by an external magnetic field (Endoroboter), the position change be displayed by a suitable visual and / or acoustical signal. If the movement of the miniaturized medical device is initiated by an operator, then this can cause corresponding correction movements of the miniaturized medical device.

The preferably three-axis gyroscope can be embodied, for example, as a gyro gyroscope, as a CVG (Coriolis Vibratory Gyroscope) or as an optical gyroscope, for example a laser gyroscope. In a laser gyroscope, a laser beam is split by a mirror arrangement into two sub-beams, both of which pass through a ring and are detected by a detector. As the system rotates, the path lengths of the two sub-beams change as far as the detector, which results in a phase shift of the two sub-beams relative to one another ("Sagnac effect"). From this phase shift, the rotational speed of the gyroscope and, in turn, the solid angle of the probe can be determined.

Such miniaturized gyroscopes can be realized, for example, as MEMS (microelectromechanical systems). For example, the SIGEM project is concerned with the production of gyroscopes on the surface of conventional CMOS chips. In the future, the gyroscope functionality can be integrated into the already existing electronics (for example, for image processing).

According to a likewise preferred embodiment of the miniaturized device, the first sensor and the second sensor are each designed as a 3D Hall sensor, wherein the two independent 3D Hall sensors are spatially arranged at different locations of the miniaturized device. In addition to the 3D magnetic flux (flux density of a magnetic basic field) from which the first position information is determined, the two 3D Hall sensors thereby also detect the 3D magnetic flux gradient from which the second position information is determined.

Hereinafter, a schematically illustrated embodiment of a miniaturized device according to the invention is explained in more detail in the drawing, but without being limited thereto. The single figure shows the miniaturized device, which is designed as Endoroboter, in a longitudinal section.

1 shows an embodiment of a magnetically navigable endoscopy capsule (magnetic capsule endoscope, endorobot) which is possible within the scope of the invention. records. Endorobot 1 has a housing 2 made of biocompatible material resistant to digestive secretions occurring in the gastrointestinal tract.

The endorobot 1 further comprises a magnetic element 3, which is designed in the illustrated embodiment as perpendicular to the longitudinal axis of the housing 2 magnetized permanent magnet. As a result, the endorobot 1 can be navigated from the outside through a magnetic field, which is generated by external navigation magnets (not shown in FIG. 1). This magnetic field is usually a 6D base and gradient field generated in an examination area.

For magnetic navigation of an endo- robot, magnetic flux densities of up to 100 mT are typical

Magnetic field gradient of up to 400 itιT / m necessary. The values of the flux density gradients are currently approximately a factor of 10 above the typical values for a magnetic resonance tomography system.

The endorobot 1 according to the invention comprises a first sensor S1, which determines a first position information, and a second sensor S2, which determines a second position information. The first sensor Sl and the second sensor S2 are independent of each other.

In the illustrated embodiment, the first sensor Sl is designed as a 3D Hall sensor and the second sensor S2 as a 3D gravity direction sensor.

In this embodiment of the endo-robot 1, the SD Hall sensor S1 measures the flux density of a basic magnetic field which is used to determine, with the known amplitude of the magnetic flux, the location of the endo-robot 1 (first position information) in a hollow organ of a mammal.

The 3D gravity direction sensor S2 measures relative to an axis fixed with respect to the probe (for example Longitudinal, transverse or vertical axis) the direction of gravity, whereby the solid angle of the endorobot 1 (second position information) can be determined.

In the illustrated embodiment, the 3D gravity direction sensor S2 comprises at least one mechanical element 4, in which under the influence of gravity occurs a deformation that is detectable.

The endorobot 1 shown in FIG. 1 further comprises a detector device 5 for acquiring medically relevant data. In the exemplary embodiment shown, the detector device 5 comprises an objective 6 with a CCD chip 7 located behind it. Images are absorbed by the objective 6 and the CCD chip 7 from the environment, that is to say from the inner wall of the human or animal hollow organ. For this purpose, the endo robot 1 has a transparent dome 8 on its front side. Within the scope of the invention, instead of the CCD chip 7, a CMOS component can also be used.

Within the scope of the invention, alternatively or additionally, other sensor devices, e.g. Sensor devices having a pH sensor, a pressure sensor or a sensor for detecting the electrolyte concentration may be present.

The medically relevant data detected by the sensor device 5 are stored in an in-capsule memory unit 9, optionally processed in an in-capsule processor unit 10 and if required via an RF transmitter / receiver 11 with an antenna 12 to a not shown in the drawing given external receiver.

In the embodiment shown, the first position information of the first sensor S 1 and the second position information of the second sensor S 2 are also transmitted to the external receiver via the antenna 12 External information and control commands can also be given to the processor unit 10 arranged in the endoscopy capsule 1 via the antenna 12 and the RF transmitter / HF receiver 11.

The data exchange within the endorobot 1 and with external devices (external memory unit, external control device) takes place via an I / O interface 13, which is assigned to the processor unit 10 in the exemplary embodiment shown.

Claims

claims

1. Miniaturized device (1) with a probe (5) and with a first sensor (S1), which determines a first position information, and with a second sensor (S2), which determines a second position information, wherein the first sensor (S1) and the second sensor (S2) are independent of each other.

2. Miniaturized device (1) according to claim 1, wherein the first position information information about the location of

Probe and the second position information comprises information about the solid angle of the probe (5).

3. Miniaturized device (1) according to claim 1 or 2, wherein the first sensor (S1) and the second sensor (S2) detect according to the same physical principle.

4. Miniaturized device (1) according to claim 1 or 2, wherein the first sensor (1) and the second sensor (S2) detect according to different physical principles.

5. Miniaturized device (1) according to claim 1 or 2, wherein the first sensor (Sl) as a 3D Hall sensor and the second sensor

(S2) is designed as a 3D gravitational direction sensor.

6. Miniaturized device (1) according to claim 1 or 2, wherein the first sensor is designed as a 3D Hall sensor and the second sensor as a gyroscope.

7. Miniaturized device (1) according to claim 1 or 2, wherein the first sensor is designed as a 3D Hall sensor and the second sensor as a 3D Hall sensor.

8. miniaturized device (1) according to claim 5, wherein the 3D gravity direction sensor comprises at least one hollow sphere with a freely movable and optically detectable liquid therein and at least one optical detector for detecting the position of the optically detectable liquid.

9. miniaturized device (1) according to claim 5, wherein the 3D gravity direction sensor is designed as an acceleration sensor.

10. Miniaturized device (1) according to claim 5, wherein the 3D gravity direction sensor (S2) comprises at least one mechanical element (4) which is deformable under the influence of gravity, wherein the deformation occurring is detectable.

11. Miniaturized device (1) according to claim 5, 6 or 7, wherein the second sensor calculates its required position information at least partially from an analytical model and / or determined from a punctual detection of amplitude and flux density of a magnetic background field.

12. Miniaturized device (1) according to claim 1, which is designed as a medical device.

13. Miniaturized device (1) according to claim 12, which is designed as Endoscopy capsule.

14. Miniaturized device (1) according to claim 12, which is designed as a doroboter.