DE102011084444A1 - Method for determining limitation information describing spatial expansion of patient and e.g. ECG-device in region of X-Ray device in radiography application, involves using time-of-flight cameras as measuring device - Google Patents

Abstract

The method involves using time-of-flight cameras (14) as a measuring device. Limitation information is determined from measuring data of the measuring device. The limitation information is considered for avoiding collision of a moving component i.e. C-arm, of a medical imaging and/or treating device i.e. X-Ray device (1), with a patient (8) and/or an object (13). The limitation information is evaluated relative to a collision probability with the patient and/or the object. A region around the patient and/or the object is defined based on the limitation information. An independent claim is also included for a medical imaging and/or treating device.

Description

The invention relates to a method for determining at least one limit information from measurement data of a measuring device that describes the spatial extent of a patient and / or an object in the region of a medical imaging and / or treatment device, in particular an X-ray device. In addition, the invention relates to a medical imaging and / or treatment device, comprising a measurement data receiving measuring device.

In the environment of medical imaging and / or treatment facilities, it may be provided for various reasons to determine the position of the patient and / or other objects, in particular the spatial limitations of the patient, at least partially and / or at least approximated. For this purpose, usually measuring devices, in particular sensors, are used to record measurement data, from which the required limiting information can be derived. Particularly useful are such limitation information in X-ray devices, which have a C-arm as a movable component.

Thus, collision avoidance systems are known precisely in the field of such X-ray devices with C-arm, in which it is to be avoided that the moving C-arm collides with the patient or objects. A medical imaging system and a collision protection method for such, for example, from DE 10 2005 023 165 A1 known. Therein, the movement of a movable part, for example a C-arm, is stopped or slowed down when the part enters an individual protection zone enveloping the patient. This is calculated individually from the surface of the patient detected by an optical sensor for each patient, wherein the optical sensor preferably comprises a light source and at least one camera and a three-dimensional shape determination is proposed based on observation of stripe patterns projected onto the patient. From this, for example, a three-dimensional model of the patient can be created, which approximates the surface of triangles.

Another system using limitation information is off DE 10 2009 021 239 A1 which relates to a method for monitoring the x-ray dose administered to a patient by a radiation source in an x-ray device. It is proposed that a location-dependent dose value be determined on the surface of the patient described by a patient model, taking into account parameters that describe the acquisition geometry and the radiation administered to an x-ray device. In this way, the skin dose should be tracked on the surface of the patient, so that the doctor can take into account the dose burden of the patient's skin when planning his admission. It is proposed to determine a positioning of the patient by a measuring means, whereby a simple patient model can be adapted. However, it is also possible, in particular with a camera and / or ultrasound, to record measured values / images that can be used to create and / or adapt the patient model or to determine the surface of the patient.

Also known for the skin dose calculation are systems in which models are created with the aid of cylinders and balls, which are adapted to the individual anatomical conditions based on the size and weight of the patient, the patient data are entered manually by the doctor and the patients below be positioned on the table in order to obtain meaningful results in the context of the skin dose calculation.

In the known possibilities for determining limitation information, it is disadvantageous that a very large evaluation effort is required in order to determine three-dimensional boundary information from the images or measured values obtained by the cameras or other measuring means, and thus two-dimensional information. The known algorithms are error-prone and inaccurate, so that nowadays usually the movement speed is limited in a C-arm, since no sufficiently reliable and / or collision detection is possible.

The invention is therefore based on the object to obtain an improved method for determining limiting information in the context of medical imaging and / or treatment with a medical imaging and / or treatment device.

To solve this problem, it is provided according to the invention in a method of the type mentioned that a time-of-flight camera is used as a measuring device.

According to the invention, it is therefore proposed to realize the optical patient and / or object detection with regard to limiting information (often also referred to as "shape detection") with the aid of a time-of-flight camera, in particular in the field of radio and angiography. Time-of-flight cameras (often also short TOF cameras) are basically known and form measuring devices that measure distances with the time of flight method and thus provide three-dimensional information. For this purpose, the scene to be recorded, in the present case the object and / or the patient, is illuminated by means of a light pulse and the time required for the light to reach the patient and / or object and back again is measured for each pixel, the required time is directly proportional to the distance. A specific example of TOF cameras is the so-called PMD (photonic mixing device) technique, which uses modulated, incoherent light (often infrared light). The light is reflected by visible objects and can be received, for example, in a matrix of solid state image sensors of CMOS technology. Finally, the received optical signal is compared with the reference signal of the modulated, incoherent illumination, so that the distance information results from the phase shift of the received signal.

Thus, TOF cameras already provide three-dimensional information from the inside, so that calculation times can be reduced and individual, patient or object-specific limiting information can be obtained. In particular, TOF cameras allow a very fast dynamic object detection, which also makes it possible to perform an immediate stop of moving components of the imaging and / or treatment device in an imminent collision, so that faster movement speeds of the components, in particular a C-arm, conceivable are.

In a particularly advantageous embodiment of the present invention can be provided that in an at least one moving component having imaging and / or treatment device, in particular an X-ray device with a C-arm, the limiting information to avoid collision of the moving component with the patient and / or the object is taken into account. Especially in the field of collision avoidance, the use of a TOF camera has particular advantages, as has already been shown. Thus, in a concrete embodiment, it can be provided, for example, that limiting information relating to the component is determined from the measured data during a movement of the component and evaluated with regard to a probability of collision with the patient and / or the object. Such an evaluation makes sense in particular in the case of dynamic monitoring of collision risks, which can be carried out practically in real time on the basis of the TOF camera supplying information directly in three dimensions. The detection range of the TOF camera is to be chosen such that at least one in particular collision-prone part of the patient and / or object as well as an environment of the patient and / or the object is contained therein, so that in the environment of the patient and / or Object emerging component can be detected and quickly assessed, so that, for example, when the collision probability exceeds a threshold value, an emergency stop of the component can be performed and the like.

In addition, it is also conceivable that an area around the patient and / or the object into which the component is not allowed to penetrate is defined on the basis of the boundary information and / or that the boundary information is taken into account during path planning of the component. For example, therefore, a kind of "protection zone" around the patient can be precisely defined on the basis of the limitation information, whereby such an area can already be taken into account particularly advantageously within the framework of path planning of the component. Thus, in the case of pre-planned movements of the component, in particular of a C-arm, a safe distance is always maintained around the patient. The described dynamic real-time monitoring as an additional security measure can thus be used to create an overall improved collision avoidance system.

As already mentioned, the limiting information determined from the measurement data of a time-of-flight camera is particularly suitable for determining and / or adapting a model describing the surface of the patient taking into account the limiting information. It is thus possible to use the limiting information particularly advantageously for determining a model of the patient, ie a patient model, it being noted at this point that such a patient model can also be used particularly advantageously in the context of a collision avoidance system. Different variants are conceivable, for example abstracted patient models constructed from cylinders and / or balls, which are adapted on the basis of the limiting information, but it is preferred if the surface information to be derived from the limiting information directly contributes to the creation of an individual, extremely accurate model of the surface of the patient is used, so that individual characteristics of the patient, such as loss of growth or the like, can be considered.

In this context, it is expedient to determine a location-dependent dose value on the surface of the patient described by the patient model and to display a representation of the dose value and / or a value derived therefrom in the case of an x-ray device taking into account parameters describing the radiation geometry and the administered radiation. The patient model can therefore ultimately a skin dose monitoring system will be provided which uses the precise information together with the radiation geometry and the type of radiation administered to determine as closely as possible a location-dependent dose value, the so-called skin dose, on the surface of the patient. A representation of the dose value or a value derived therefrom constitutes an extremely useful aid for the treating person, in particular a doctor, in order to judge how further images and / or treatments are to be performed in order to avoid skin damage and the like. Thus, the more accurate patient model provided by the time-of-flight camera readings allows better information on the skin dose to be obtained and thus distributes the radiation more homogeneously to the patient through the skin dose calculations. In this context, it can also be provided that proposals for further irradiation steps, for example further projections to be recorded with an X-ray device using a C-arm, are determined and also displayed to a treating person. The treating person can therefore influence the skin dose in the further course of the imaging or treatment.

In an advantageous development of the present invention, it can generally be provided that the time-of-flight camera records the measurement data by emitting and receiving light with a frequency of one THz or more than one THz. While, whenever the patient is uncovered on a patient table, imaging by the TOF camera in the optical range is sufficient, in other cases, it is extremely advantageous to use TOF cameras operating in the THz range. This makes it possible, for example, through blankets that are found over the patient to detect body contours and yet provide a more accurate patient model available. Such is not conceivable with conventional measuring devices.

In a further advantageous embodiment of the present invention can be provided that at least one patient information characterizing the patient, in particular a gender and / or a size and / or weight of the patient is determined from the limitation information, either by comparison with, in particular in the frame a patient registration and / or from an information system, present reference patient information is carried out a plausibility check or the patient information is used as part of a patient registration and / or in an information system. Consequently, a further evaluation of the limiting information and / or the measured data can be carried out to determine patient information, for example the sex, the size and / or a weight, for example by checking for specific characteristics with respect to sex, dimensions of the determined ones Surface area is determined and considered in terms of weight, the enclosed volume. This patient information can be of use in two ways. On the one hand, they can serve for checking the plausibility by taking a comparison with already existing reference patient information, which is usually entered as part of a patient registration or even retrieved from an information system, for example a hospital information system or a radiology information system. Thus, if a plausibility check is carried out in one direction, for example checking whether the correct patient has been placed on the patient table or, in the case of a plausibility check in the other direction, the reliability of the measured data and the limiting information can be assessed. Preference is given to a mutual plausibility check. In another, alternative embodiment, however, it is also conceivable that the patient information is used in the context of a patient registration and / or in an information system. This means, in particular in the context of patient registration, that a person to be treated or examined does not have to enter the data manually, but can also be automatically determined; in particular, current values can also be determined which are ultimately stored in an information system, for example in a hospital information system or a hospital Radiology information system, can be stored.

Furthermore, it is advantageous if markers arranged on a patient table, in particular three-dimensionally structured markers, are localized in the measurement data and from this a relative position information of the patient on the table is derived. Thus, if markers are attached to the patient table which are detected by the TOF camera in addition to the patient, the relative positioning of the patient on the table can also be checked, in particular with regard to infants as patients. The relative position information can be used, for example, to determine operating parameters of the imaging and / or treatment device and the like.

The time-of-flight camera may be arranged on a ceiling of a room in which the imaging and / or treatment device is arranged. With skillful positioning, for example, an entire patient table together with patients and / or objects positioned thereon can be just as located in the detection range of the TOF camera as movable components of the imaging and / or treatment device. Especially advantageous it is in this context, if at least two TOF cameras are used, which record the scenery from different angles. However, it is also conceivable to otherwise arrange the TOF camera, in particular moved along a movable component, in particular a C-arm, of the imaging and / or treatment device. For example, the TOF camera may also be used as a distance sensor or the like if its detection area is oriented in the direction of movement.

It should be noted at this point that the TOF camera can be calibrated with the imaging and / or treatment device, for example by using recognizable calibration bodies from both the TOF camera and the imaging and / or treatment device. In this way, measured data recorded by the TOF camera and limiting information determined therefrom can be easily transferred into the coordinate system of the imaging and / or treatment device.

As already mentioned, it can advantageously be provided that at least two time-of-flight cameras are used. In this way, information can be obtained from different directions of view, which can be compared against each other on the one hand, but can also record different areas of the surface of the patient and / or object in order to contribute to an even better measurement. The accuracy of the measurement is further increased if, to determine the limiting information, a plurality of measurement data records recorded chronologically one after the other are statistically evaluated. In this way, inaccuracies in the time resolution, which can lead to measurement errors with respect to the distance of the pixel from the TOF camera, can be significantly reduced. Finally, it is still possible to improve the measurement accuracy by frequency variation, as is already known in the prior art.

In addition to the method, the invention also relates to a medical imaging and / or treatment device, comprising a measuring device receiving measurement data, which is designed as a time-of-flight camera, and one for determining the spatial extent of a patient and / or an object in the area of the medical imaging and / or treatment device descriptive limiting information formed from the measurement data control device. The medical imaging and / or treatment device is therefore designed to carry out the method according to the invention, so that all statements regarding the method according to the invention can also be applied to the medical imaging and / or treatment device according to the invention, with which the advantages of the present invention are also obtained can be.

It can be provided that the imaging and / or treatment device has at least one moving component, in particular the imaging and / or treatment device embodied as an X-ray device has a C-arm as a moving component. The limitation information can then be used particularly advantageously in the context of collision avoidance.

For this purpose, provision can be made for the imaging and / or treatment device to comprise a collision avoidance system, in particular comprising the control device, which is designed to utilize the limit information. As has already been explained with regard to the method according to the invention, dynamic real-time monitoring of the risk of collision can also be realized, in particular by means of the faster data acquisition and processing. Furthermore, provision can be made for the imaging and / or treatment device to have a monitoring system monitoring the skin dose administered to the patient, in particular the control device, which is designed to utilize the limiting information. In this case, but also in the context of the collision avoidance system, it is particularly advantageous if the control device is designed to determine and / or adapt a patient model on the basis of the limitation information. It can be obtained by means of a TOF camera extremely accurate information and thus a very accurate description of the surface of the patient, which can be used by collision avoidance systems and / or surveillance systems particularly advantageous.

It may further be provided that the time-of-flight camera is arranged on a ceiling of a space accommodating the imaging and / or treatment device and / or on a movable component of the imaging and / or treatment device, in particular a C-arm is. In addition, as already described with respect to the method, it is particularly advantageous that at least two time-of-flight cameras can be provided which view the patient and / or the object from different angles.

Further advantages and details of the present invention will become apparent from the embodiments described below and with reference to the drawing. Showing:

1 an X-ray device according to the invention in a first exemplary embodiment,

2 an inventive X-ray device in a second embodiment, and

3 a schematic diagram for carrying out the method according to the invention.

1 shows a schematic diagram of a first embodiment of an X-ray device according to the invention 1 as a medical imaging device. It includes one present on a robotic arm 2 arranged C-arm 3 on which there is an X-ray source opposite 4 and an x-ray detector 5 are arranged. The C-arm 3 is by means of the robot arm 2 and other drive means controlled by a control device 6 in different positions for receiving one on a patient table 7 arranged patients 8th movable. The control device 6 In addition to a non-illustrated input means also includes a display device 9 , here a monitor. She is using an information system via a network 10 , for example, a hospital information system and / or a radiology information system.

The X-ray device 1 is in a space indicated here only 11 with a blanket 12 arranged. On the ceiling 12 are now as measuring devices for recording measurement data relating to the patient 8th and further optionally in the path of movement of the C-arm 3 arranged as a movable component objects 13 For example, ECG devices, injectors, head holders and the like, time-of-flight cameras 14 provided, in the present case two at different angles the area of the patient table 7 capturing TOF cameras 14 , The TOF cameras 14 work in the THz range, ie at frequencies of the emitted light of a THz or higher, so that even in cases in which the patient 8th Under a blanket, information about its spatial extent can be obtained.

The measurement data of the TOF cameras 14 be by means of the control device 6 to the surface of the patient 8th and / or the object 13 evaluated descriptive limiting information, which then for the patient 8th be converted into a patient model, which will be discussed in more detail below. The bounding information regarding the object 13 and the patient 8th as well as the patient model can then of a here only hinted collision avoidance system 15 and a skin dose monitoring system 16 be used. Such systems 15 . 16 are already known in the art and should not be further specified here if they go beyond the present invention.

On the patient table 7 are three-dimensionally structured markers 17 arranged, for example, may have different three-dimensional patterns and thus in the measurement data of the TOF cameras 14 can be detected and identified. With the help of these markers 17 It is also possible to have a relative position of the patient 8th on the patient table 7 to determine and, for example, to check a positioning or setting of operating parameters by the controller 6 be used. It should be noted at this point that when determining the limit information and other information from the measurement data of the TOF cameras 14 always several chronologically consecutive measured data sets are considered in order to improve the accuracy by a statistical evaluation. In addition, it can be provided that a frequency variation is performed in order to likewise obtain an improvement in the accuracy of the measurement.

2 shows a second embodiment of an X-ray device according to the invention 1 , except for the arrangement of time-of-flight cameras 14 the X-ray device 1 equivalent. At the X-ray device 1 are the TOF cameras 14 visible on the C-arm 3 arranged and are moved with this.

3 now shows a schematic diagram for carrying out the method according to the invention, to which the control devices 6 the X-ray equipment 1 . 1 are formed. It will be in one step 18 the measurement data taken and the limit information 19 related to the patient 8th or the object 13 , evaluated. This limit information 19 are now used in three ways. For one, they are in the collision avoidance system 15 used during a dynamic monitoring, that means during a movement of the C-arm 3 Measurement data is recorded, limit information 19 determined and evaluated so that a collision probability is determined. If this exceeds a threshold value, for example, in one step 20 an emergency stop of the C-arm 3 to be triggered.

In addition, based on the limiting information 19 a the surface of the patient 8th descriptive patient model 22 in one step 21 determined or adjusted. The patient model 22 should as accurately as possible the surface of the patient 8th describe. The patient model 22 will initially also the collision avoidance system 15 provided, for example, where this is an area around the patient 8th can be determined So a short-range zone or protection zone, in which the C-arm 3 not allowed to bring in. This area can then be taken into account during path planning or the like.

In addition, the patient model becomes 22 but also to the skin dose monitoring system 16 which, taking into account the radiation geometry, in this case the acquisition geometry, and the parameters describing the radiation administered, a location-dependent dose value (skin dose) on the basis of the patient model 22 described surface of the patient 8th determined and generates a representation of the dose value (or a value derived therefrom) and on the display device 9 displays. It can also be provided that the monitoring system 16 Proposals for future recorded projection images makes to achieve the most homogeneous distribution of the skin dose.

Finally it is still possible to step 23 that the limit information 19 in the control device 6 be processed to determine patient information, such as the gender, size and weight of the patient, which then, for example, with reference information of the patient information system 10 be reconciled within the framework of a mutual plausibility check. However, it is also possible, in particular when there is still no patient information, to use it directly in the context of patient registration so that the person having the treatment does not have to enter it.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

X-ray equipment

1

 X-ray equipment

2

robot arm

3

C-arm

4

X-ray

5

X-ray detector

6

control device

7

patient table

8th

patient

9

display device

10

information system

11

room

12

blanket

13

object

14

Time-of-flight camera

15

system

16

system

17

marker

18

step

19

limiting information

20

step

21

step

22

patient model

23

step

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005023165 A1 [0003]
• DE 102009021239 A1 [0004]

Claims (14)

Method for determining at least one of the spatial extent of a patient ( 8th ) and / or an object ( 13 ) in the region of a medical imaging and / or treatment device, in particular an X-ray device ( 1 . 1' ), descriptive limit information ( 19 ) from measurement data of a measuring device, characterized in that a time-of-flight camera ( 14 ) is used. A method according to claim 1, characterized in that in an at least one moving component having imaging and / or treatment device, in particular an X-ray device ( 1 . 1' ) with a C-arm ( 3 ), the limit information ( 19 ) for avoiding a collision of the moving component with the patient ( 8th ) and / or the object ( 13 ) is taken into account. A method according to claim 2, characterized in that during a movement of the component also a limitation information ( 19 ) with respect to the component is determined from the measured data and with regard to a probability of collision with the patient ( 8th ) and / or the object ( 13 ) and / or that on the basis of the limit information ( 19 ) an area around the patient ( 8th ) and / or the object ( 13 ), in which the component is not allowed to penetrate, is defined and / or that the limit information ( 19 ) is taken into account during path planning of the component. Method according to one of the preceding claims, characterized in that the surface of the patient ( 8th ) descriptive patient model ( 22 ) taking into account the limitation information ( 19 ) is determined and / or adjusted. Method according to claim 4, characterized in that in the case of an X-ray device ( 1 . 1' ), taking into account parameters which describe the radiation geometry and the administered radiation, a location-dependent dose value on the basis of the patient model ( 22 described surface of the patient ( 8th ) and a representation of the dose value and / or a value derived therefrom is displayed. Method according to one of the preceding claims, characterized in that the time-of-flight camera ( 14 ) receives the measurement data by emitting and receiving light having a frequency of one terahertz or more than one terahertz. Method according to one of the preceding claims, characterized in that at least one of the patients ( 8th ) characterizing patient information, in particular a gender and / or a size and / or a weight of the patient ( 8th ), from the limit information ( 19 ), either by comparison with, in particular in the context of a patient registration and / or from an information system ( 10 ), the reference patient information is checked for plausibility, or the patient information is provided as part of a patient registration and / or in an information system ( 10 ) is being used. Method according to one of the preceding claims, characterized in that on a patient table ( 7 ) ( 17 ), in particular three-dimensionally structured markers ( 17 ), localized in the measured data and from this a relative position information of the patient ( 8th ) on the patient table ( 7 ) is derived. Method according to one of the preceding claims, characterized in that one on a ceiling ( 12 ) of a room ( 11 ), in which the imaging and / or treatment device is arranged, and / or on a movable component, in particular a C-arm ( 3 ) in an X-ray device ( 1 . 1' ), the imaging and / or treatment device, arranged time-of-flight camera ( 14 ) is used. Method according to one of the preceding claims, characterized in that at least two time-of-flight cameras ( 14 ) and / or to determine the limit information ( 19 ) are evaluated statistically recorded several temporally successive measured data records. Medical imaging and / or treatment device, comprising a measuring data receiving measuring device, which is used as a time-of-flight camera ( 14 ) and one for determining the spatial extent of a patient ( 8th ) and / or an object ( 13 ) in the area of the medical imaging and / or treatment facility descriptive limiting information ( 19 ) control device formed from the measured data ( 6 ). Imaging and / or treatment device according to claim 11, characterized in that it comprises at least one moving component, in particular as X-ray device ( 1 . 1' ) trained imaging and / or treatment device as a moving component a C-arm ( 3 ) having. Imaging and / or treatment device according to claim 11 or 12, characterized in particular that the control device ( 6 ) comprehensive collision avoidance system ( 15 ), which is to use the limit information ( 19 ) is formed, and / or the the patient ( 8th ) administered skin dose, in particular the control device ( 6 ) comprehensive monitoring system ( 16 ), which is to use the limit information ( 19 ) is formed. Imaging and / or treatment device according to one of claims 11 to 13, characterized in that the time-of-flight camera ( 14 ) on a ceiling ( 12 ) of the imaging and / or treatment device receiving space ( 11 ) and / or on a movable component of the imaging and / or treatment device, in particular a C-arm ( 3 ) is arranged.

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