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Title:
X-RAY APPARATUS EQUIPPED WITH AN INCLINOMETER
Document Type and Number:
WIPO Patent Application WO/2013/090481
Kind Code:
A1
Abstract:
An X-ray apparatus comprising an X-ray tube (2), an X-ray detector (4) disposed opposite the X- ray tube in a direction of emission of X-rays, a mobile device (8) capable of moving the X-ray apparatus on which the X-ray tube (2) and the X-ray detector (4) are mounted, and a positioning system (11, 13), designed for determining the position of the apparatus within an examination room. The positioning system (11, 13) comprises means (14) for correcting the position of the apparatus determined by the positioning system as a function of the inclination of the apparatus with respect to the ground.

Inventors:
BOUVIER BERNARD (FR)
Application Number:
PCT/US2012/069334
Publication Date:
June 20, 2013
Filing Date:
December 13, 2012
Export Citation:
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Assignee:
GEN ELECTRIC (US)
International Classes:
A61B6/00
Foreign References:
EP1782735A22007-05-09
DE102005052784B32007-07-26
FR2953119A12011-06-03
FR2945724A12010-11-26
Attorney, Agent or Firm:
GNIBUS, Michael, M. et al. (Global Patent Operation2 Corporate Drive, Suite 64, Shelton CT, US)
Download PDF:
Claims:
CLAIMS

What Is Claimed Is:

1. An X-ray apparatus, comprising:

an X-ray tube (2);

an X-ray detector (4) disposed opposite the X-ray tube in a direction of emission of X- rays;

a mobile device (8) capable of moving the X-ray apparatus on which the X-ray tube and the X-ray detector are mounted; and

a positioning system (11, 13) designed for determining the position of the apparatus within an examination room, characterized in that the positioning system (11, 13) comprises means (14) for correcting the position of the apparatus determined by the positioning system (11, 13) as a function of the inclination of the apparatus with respect to the ground.

2. The X-ray apparatus according to Claim 1, characterized in that the X-ray apparatus comprises a means for measurement of inclination (14) placed within the apparatus.

3. The X-ray apparatus according to Claim 2, characterized in that the inclination measurement means comprise an inclinometer.

4. The X-ray apparatus according to either of Claims 2 and 3, characterized in that the inclination measurement means is connected to a processor (15) designed to determine the true position of the apparatus from the position delivered by the positioning system and from the angle of inclination of the apparatus delivered by the inclination measurement means.

5. The X-ray apparatus according to Claim 4, characterized in that the processor (15) is associated with a cartography (16) in which is stored a set of position offset values as a function of values of inclination delivered by the inclination measurement means.

6. The X-ray apparatus according to Claim 4, characterized in that the inclination measurement means is designed to supply an inclination measurement solid angle, the processor (15) comprising trigonometric calculation means for generating a position offset value.

7. The X-ray apparatus according to any one of Claims 1 to 6, characterized in that the X-ray apparatus comprises means (15) for comparing a measurement of angle of inclination with a safety threshold value for causing the mobile device (8) to stop as soon as the measured value of the angle of inclination exceeds the said threshold value.

Description:
X-RAY APPARATUS EQUIPPED WITH AN INCLINOMETER

BACKGROUND OF THE INVENTION

[0001] The present invention generally relates to X-ray devices notably used in the field of medical imaging.

[0002] It relates more particularly to X-ray devices installed on a mobile system and accordingly capable of moving automatically, notably independently.

[0003] As is known, X-ray devices conventionally comprise an X-ray tube and an X-ray detector disposed opposite the X-ray tube in a direction of emission of the X-rays. The tube and the detector are generally placed on two mutually opposing ends of an arm.

[0004] Such devices are used for angiographic examinations for diagnostic or surgical intervention purposes.

[0005] During these examinations, X-ray radiographies need to be taken of a region of interest on the body of a patient. For this purpose, with the patient lying on an examination table, the X-ray tube and the detector are positioned facing the region to be X-ray imaged.

[0006] In the prior art, there exist several types of X-ray devices allowing X-ray images to be taken.

[0007] X-ray devices fixed to the ground are first of all known, in which the arms supporting the X-ray tube and the detector comprise several degrees of freedom allowing the X-ray beam to be positioned facing the region of interest.

[0008] This type of apparatus however has a major drawback relating to the fact that the X- ray images are only needed at the start and at the end of an operation. In the meantime, it is the access to the patient that must take precedent. They cannot therefore be moved away from the examination table when they are not used. In particular, the transfer and the installation of the patient onto the examination table are impeded by the presence of this cumbersome system.

[0009] There furthermore exist X-ray devices referred to as "surgical mobile units" that are moveable manually. In this case, they are mounted on a trolley with a certain number of batteries on board used to supply power to the X-ray tube. This type of apparatus is not then suitable for angiographic examinations in the sense that the required power delivered by the X-ray tube is no longer sufficient for obtaining a sufficient quality of image or, in particular, a sufficient contrast.

[0010] Moreover, this type of X-ray apparatus does not allow complex angular positioning because the diameter of the arm supporting the tube and the detector is not large enough. Similarly, these mobile X-ray devices do not reach high enough speeds of rotation to enable high-quality three-dimensional images to be reconstructed. Lastly, even if the weight of such an apparatus is twice as small as that of an X-ray apparatus designed for angiography, it remains very difficult to move owing to its relatively large dimensions and to its weight, which can reach 300 kg.

[0011] A system has furthermore been developed with the X-ray apparatus installed on a mobile device mounted on wheels automatically driven by drive motors under the control of a navigation system. With regard to this system, reference may be made to the document FR 2 945 724.

[0012] It has been observed that such a system is particularly effective for moving the X-ray apparatus in an operating theatre or examination room, notably to position the X-ray tube and the detector around the region of interest and to move it away when it is no longer used, in order to free up the space around the examination table.

[0013] These mobile X-ray devices are furthermore associated with a positioning system capable of precisely localizing the X-ray apparatus in the room and, notably, with respect to an examination table.

[0014] The positioning system may, for example, comprise a laser emitter coupled with a sensor and placed at the end of an arm rising vertically from the housing of the apparatus, a set of reflecting platelets disposed on the wall of the operating theatre and a processor capable of calculating the exact position of the apparatus based on a measurement of angle and/or of distance between the emitter and the platelets, using the radiation emitted by the laser emitter, reflected by the platelets and sensed by the sensor.

[0015] It has however been observed that variations, even minimal, of the flatness of the floor could generate relatively large shifts between the true position of the apparatus and the position determined by the positioning system.

[0016] For example, a shift of 4 mm between the true position of the apparatus and the position such as determined by the positioning system corresponds to an error of around 40% with respect to a position determined by the positioning system with a precision of the order of a centimetre.

[0017] The aim of the invention is thus to provide an X-ray apparatus that overcomes this drawback and that improves the precision of the localization determined by the positioning systems.

[0018] The subject of the invention is therefore an X-ray apparatus, comprising an X-ray tube, an X-ray detector disposed opposite the X-ray tube in a direction of emission of X-rays, a mobile device capable of moving the X-ray apparatus and on which the X-ray tube and the X-ray detector are mounted, and a positioning system designed for determining the position of the mobile apparatus within an examination room. BRIEF SUMMARY OF THE INVENTION

[0019] According to a general feature of the invention, the X-ray apparatus furthermore comprises means for correcting the position of the apparatus determined by the positioning system as a function of the inclination of the apparatus with respect to the ground.

[0020] An inclination measurement means will notably be used, notably an inclinometer placed within the apparatus.

[0021] According to yet another feature, the inclination measurement means is connected to a processor designed to determine the true position of the apparatus from the position delivered by the positioning system and from the angle of inclination of the apparatus delivered by the inclination measurement means.

[0022] For example, the processor is associated with a cartography in which is stored a set of position offset values as a function of values of inclination delivered by the inclination measurement means.

[0023] As a variant, the inclination measurement means is designed to supply an inclination measurement solid angle, the processor comprising trigonometric calculation means for generating a position offset value.

[0024] In one embodiment, the apparatus comprises means for comparing a measurement of angle of inclination with a safety threshold value and for causing the mobile device to stop as soon as the measured value of the angle of inclination exceeds the said threshold value.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other aims, features and advantages of the invention will become apparent upon reading the following description, presented solely by way of non-limiting example, and with reference to the appended drawings, in which:

[0026] Figure 1 is a schematic view of an X-ray apparatus having a mobile device equipped with correction means for correcting the position of the apparatus determined by a positioning system; and

[0027] Figure 2 is a schematic diagram of the processor for the apparatus in Figure 1, illustrating one example of generation of position offset values.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Figure 1 illustrates a mobile X-ray imaging apparatus 1 according to the invention.

[0029] As can be seen, this apparatus 1 essentially comprises an X-ray tube 2, capable of emitting a beam 3 of X-rays in a direction of emission, and an X-ray detector 4 disposed at the two mutually-opposing ends of an arm 5, here in the form of a bow arc, such that the X-rays emitted by the tube 2 are incident on the detector 4.

[0030] As can be seen, the arm 5 is installed in a sliding fashion on a second arm 6 mounted in a rotatable manner onto a fixed support 7, itself mounted onto a mobile device 8.

[0031] Thus, the support 7, the rotating arm 6 and the arm 5 are all three articulated with respect to one another in such a manner that the X-ray apparatus can move in three dimensions and thus acquire images of an organ to be examined under various angles of incidence.

[0032] During an X-ray imaging operation, the tube 2 and the detector 4 are positioned facing a region of interest on the body 9 of a patient lying on an examination table 10 such that, when the region of interest is interposed between the X-ray tube 2 and the detector 4, it is irradiated by the X-rays and the detector 4 produces data representative of features of the interposed region of interest. [0033] In the exemplary embodiment shown, the mobile device 8 comprises a housing C supported by a rolling bearing system comprising, for example, two lateral driving and steering wheels placed at the rear, two free front wheels, and means for powering the driving wheels disposed within the housing C and comprising a steering motor coupled to a drive motor. The mobile device 8 is a programmable device and is associated with a navigation device allowing the apparatus 1 to be precisely localized within the room and, notably, with respect to the examination table 10.

[0034] Thus, according to programmed phases or under the control of a control panel that can be manipulated by an operator, the X-ray apparatus is capable of automatically moving around within the operating theatre.

[0035] Such is in particular the case, notably, during the positioning of the X-ray apparatus facing the examination table in order to dispose the tube 2 and the detector 4 in front of a region of interest to be X-ray imaged or during the movement of the X-ray apparatus to a remote parking position when it is no longer in use.

[0036] The navigation device is for this purpose associated with a positioning system capable of precisely localizing the X-ray apparatus within the operating theatre and, notably, the X-ray tube and the detector with respect to the examination table.

[0037] The positioning system can, for example, be based on the use of a laser emitter/receiver 11 placed at the top end of an arm 12 protruding vertically from the apparatus together with a set of targets, such as 13, regularly disposed on the surrounding walls of the operating theatre.

[0038] A processor, installed onboard the X-ray apparatus 1 and duly programmed, calculates by telemetry the position of the apparatus based on the laser beams emitted by the emitter/receiver 11, reflected by the targets 13 and detected by a sensor associated with the transmitter/receiver 11.

[0039] Other positioning systems can however be used while still remaining within the scope of the invention.

[0040] Thus, as a variant, a positioning system could be used based on the use of an antenna placed at the top end of the arm 12 and capable of establishing a radio link with radio frequency identification devices placed on the wall of the operating theatre and comprising a memory chip designed to store, notably, position coordinates, a processor, and a radio antenna in such a manner that the apparatus is capable of positioning itself using the coordinates received coming from the targets.

[0041] The X-ray apparatus 1 is also equipped with means designed to correct the position of the apparatus such as determined by the positioning system, based on its inclination with respect to the ground.

[0042] As can be seen in Figure 1, the apparatus 1 is thus equipped with an inclination measurement means, notably an inclinometer 14. Any suitable sensor could however also be used to measure the inclination of the apparatus.

[0043] This inclinometer can be placed on an electronic board, for example situated at the rear of the apparatus. However, as shown, it may also be situated on the arm 12 close to the laser emitter/receiver 11. As will be described in detail hereinbelow, the positioning of the inclinometer 14 close to the emitter is advantageous when the correction is based on a calibration of the apparatus.

[0044] Indeed, the inclinometer 14 supplies values of angle of inclination of the apparatus with respect to the ground. According to a first exemplary embodiment, the processor installed onboard the X-ray apparatus 1, or potentially located remotely, acquires the measurements of angle of inclination supplied by the inclinometer 14, together with the directions of inclination in order to deduce from these, by trigonometric calculation, a shift in position with respect to the value of position coming from the positioning system based on the use of the laser emitter/receiver 11 and of the targets 13.

[0045] However, according to a second advantageous embodiment, and with reference to Figure 2, the processor 15 is associated with a cartography 16 in which are stored a set of position offset values Vij for each position of the apparatus determined by processing of the distance measurements coming from the laser emitter/receiver 11 , as a function of the values of angle of inclination coming from the inclinometer 14. Such values Vij are obtained by prior learning during an initial calibration phase of the X-ray apparatus 1 by positioning it, for example, on a perfectly flat pedestal and by recording, for various values of inclination of the pedestal, in two orthogonal directions, the measurements coming from the laser emitter/receiver 1 as a function of the angles of inclination obtained by the inclinometer 14. It is thus possible to correct the result of the measurement coming from the transmitter/receiver 11 using inclination data.

[0046] It has in particular been observed that the use of a navigation device comprising a positioning system coupled with an inclinometer allowed the position of the X-ray apparatus to be calculated with a precision of the order of 1 mm.

[0047] It will however be noted that the processor furthermore incorporates comparison means providing a calculation of comparison between the angle of inclination coming from the inclinometer 14 and a safety threshold value, stored in memory, in order to cause the mobile device to stop 8 when the measured value of angle of inclination exceeds the threshold value. [0048] This threshold value can for example be around 10°. The apparatus thus incorporates a safety function that can be implemented so as to stop the mobile device when a risk of the apparatus overturning occurs.

[0049] As will be apparent, the invention just described, which relates to an X-ray apparatus, comprising an X-ray tube, an X-ray detector disposed opposite the X-ray tube in a direction of emission of the X-rays, a mobile device capable of moving the X-ray apparatus and on which are mounted the X-ray tube and the X-ray detector, and a positioning system designed for determining the position of the mobile apparatus within an examination room and which comprises an inclinometer associated with a processor for correcting the position of the apparatus determined by the positioning system as a function of the inclination of the apparatus with respect to the ground, allows the localization precision provided by the positioning system to be considerably improved.