MEDICAL INSTALLATION, AND METHOD FOR CONTROLLING A MEDICAL APPARATUS THEREIN

Abstract

In a method to control a medical apparatus of an installation having: a contact device for a patient, at least one electrical potential sensor that can be coupled to the body of said patient is integrated into the contact device. A signal evaluation device is provided with measurement signals generated with the electrical potential sensor for evaluation. The medical apparatus is connected with the signal evaluation device, and measurement signals that relate to the breathing and/or cardiac activity of the patient are acquired with the at least one electrical potential sensor coupled to the body of said patient upon contact of the patient with the contact device. Trigger signals are generated with the signal evaluation device based on the measurement signals that relate to the breathing cycle and/or the cardiac cycle of the patient. Operation of the medical apparatus is controlled based on the trigger signals.

Claims

1. A method to control a medical apparatus of a medical installation, said medical apparatus having an interior opening in which an interaction region of the medical apparatus is located, in which radiation is emitted into a patient in the opening or radiation is detected from a patient in the opening, said method comprising: placing a clothed patient on a movable patient support surface in said medical apparatus, said patient support surface being selected from the group consisting of a patient support plate of a patient support table, and a placement mat configured to be arranged on a patient support plate of a patient support table, said patient support surface comprising a plurality of electrical potential sensors integrated therein to form a two-dimensional signal matrix, that each interact with the body of the clothed patient, each electrical potential sensor being comprised of at least three electrodes that are each capacitively coupled to the patient; with at least one electrical potential sensor in said plurality of electrical potential sensors coupled to the body of the patient, generating a measurement signal that represents a physiological activity of the clothed patient selected from the group consisting of breathing activity and cardiac activity, by operating two of said electrodes of said at least one electrical potential sensor as active electrodes and a third of said electrodes of said at least one electrical potential sensor as a reference electrode with respect to said active electrodes, in order to sense a dynamic distance variation between a body surface of the patient and said active electrodes; in a signal evaluation processor supplied with said measurement signal, evaluating said measurement signal to obtain an evaluation result and, from said evaluation result, generating trigger signals; in said signal evaluation processor, also determining a position of the heart of the patient, with respect to the patient support bed, by evaluating respective measurement signals from multiple electrical potential sensors in said plurality of electrical potential sensors; in said signal evaluation processor, from the position of the heart of the patient that has been determined with respect to said patient support surface, also determining at least one of a positional attitude of the patient on the patient support surface, an alignment of the patient on the patient support surface, and a portion of the body of the patient with respect to the patient support surface; from said signal evaluation processor, controlling movement of said patient support surface, with said clothed patient thereon, in order to position said clothed patient on said patient support surface relative to said interaction region so as to cause a selected anatomical portion of the clothed patient to be situated in said interaction region; and from said signal evaluation processor, controlling operation of said medical apparatus based on said trigger signals to emit radiation or detect radiation in a timed relation to said physiological activity while said selected anatomical portion of the clothed patient is situated in said interaction region.

2. A method as claimed in claim 1 comprising, in said signal evaluation processor, generating said measurement signal that represents said physiological activity of the patient as a difference between signals respectively obtained between said active electrodes and said reference electrode.

3. A method as claimed in claim 1 comprising, in said signal evaluation processor, evaluating said measurement signal of said at least one electrical potential sensor by implementing an analysis selected from the group consisting of Fourier analysis and wavelet analysis, in order to obtain said evaluation result.

4. A method as claimed in claim 1 comprising multiplexing respective measurement signals from said multiple electrical potential sensors for supply to said processor.

5. A method as claimed in claim 1 comprising, in said signal evaluation processor, determining the position of the heart of the patient with respect to the patient support device by implementing a cross-correlation analysis of respective measurement signals originating respectively from electrical potential sensors, among said multiple electrical potential sensors, that are adjacent to each other.

6. A method as claimed in claim 1 wherein said medical apparatus is a medical imaging apparatus, and comprising, from said signal evaluation processor, controlling said operation of said imaging medical apparatus based on said trigger signals in order to operate the medical imaging apparatus to acquire image data from said anatomical portion of the clothed patient situated in said interaction region.

7. A method as claimed in claim 6 comprising selecting said medical imaging apparatus from the group consisting of x-ray computed tomography (CT) apparatuses, magnetic resonance tomography (MRT) apparatuses, positron emission tomography (PET) apparatuses, and single-photon emission computed tomography (SPECT) apparatuses.

8. A method as claimed in claim 1 wherein said medical apparatus is a radiation therapy apparatus, and comprising, from said signal evaluation processor, controlling said operation of said radiation therapy apparatus based on said trigger signals in order to cause said radiation therapy apparatus to administer radiation therapy to said selected anatomical portion of the clothed patient situated in said interaction region.

9. A medical installation comprising: a medical apparatus having an interior opening in which an interaction region of the medical apparatus is located, in which radiation is emitted into a patient in the opening or radiation is detected from a patient in the opening; a movable patient support surface in said medical apparatus, said patient support surface being selected from the group consisting of a patient support plate of a patient support table, and a placement mat configured to be arranged on a patient support plate of a patient support table, said patient support surface being adapted to receive a clothed patient thereon and said patient support surface comprising a plurality of electrical potential sensors integrated therein to form a two-dimensional signal matrix, that each interact with the body of the clothed patient, each electrical potential sensor being comprised of at least three electrodes that are each capacitively coupled to the patient; at least one electrical potential sensor in said plurality of electrical potential sensors coupled to the body of the patient being configured to generate a measurement signal that represents a physiological activity of the clothed patient selected from the group consisting of breathing activity and cardiac activity, with two of said electrodes of said at least one electrical potential sensor operated as active electrodes and a third of said electrodes of said at least one electrical potential sensor operated as a reference electrode with respect to said active electrodes, in order to sense a dynamic distance variation between a body surface of the patient and said active electrodes; a signal evaluation processor supplied with said measurement signal, configured to evaluate said measurement signal to obtain an evaluation result and, from said evaluation result, to generate trigger signals; said signal evaluation processor being configured to also determine a position of the heart of the patient, with respect to the patient support bed, by evaluating respective measurement signals from multiple electrical potential sensors in said plurality of electrical potential sensors; said signal evaluation processor, being also configured to determine, from the position of the heart of the patient that has been determined with respect to said patient support surface, at least one of a positional attitude of the patient on the patient support surface, an alignment of the patient on the patient support surface, and a portion of the body of the patient with respect to the patient support surface; said signal evaluation processor being configured to control movement of said patient support surface, with said clothed patient thereon, in order to position said clothed patient on said patient support surface relative to said interaction region so as to cause a selected anatomical portion of the clothed patient to be situated in said interaction region; and said signal evaluation processor being configured to control operation of said medical apparatus based on said trigger signals to emit radiation or detect radiation in a timed relation to said physiological activity while said selected anatomical portion of the clothed patient is situated in said interaction region.

10. A medical installation as claimed in claim 9 wherein said processor is configured to generate said measurement signal that represents said physiological activity of the patient as a difference between signals respectively obtained between said active electrodes and said reference electrode.

11. A medical installation as claimed in claim 9 wherein said signal evaluation processor is configured to evaluate said measurement signal of said at least one electrical potential sensor by implementing an analysis selected from the group consisting of Fourier analysis and wavelet analysis, in order to obtain said evaluation result.

12. A medical installation as claimed in claim 9 comprising a multiplexor that multiplexes respective measurement signals from said multiple electrical potential sensors for supply to said processor.

13. A medical installation as claimed in claim 9 wherein said signal evaluation is configured to determine the position of the heart of the patient with respect to the patient support device by implementing a cross-correlation analysis of respective measurement signals originating respectively from electrical potential sensors, among said multiple electrical potential sensors, that are adjacent to each other.

14. A medical installation as claimed in claim 9 wherein said medical apparatus is a medical imaging apparatus, and wherein said signal evaluation processor is configured to control said operation of said medical imaging apparatus based on said trigger signals in order to operate the medical imaging apparatus to acquire image data from said anatomical portion of the clothed patient situated in said interaction region.

15. A medical installation as claimed in claim 14 wherein said medical imaging apparatus is selected from the group consisting of x-ray computed tomography (CT) apparatuses, magnetic resonance tomography (MRT) apparatuses, positron emission tomography (PET) apparatuses, and single-photon emission computed tomography (SPECT) apparatuses.

16. A medical installation as claimed in claim 9 wherein said medical apparatus is a radiation therapy apparatus, and wherein said signal evaluation processor is configured to control said operation of said radiation therapy apparatus based on said trigger signals in order to cause said radiation therapy apparatus to administer radiation therapy to said selected anatomical portion of the clothed patient situated in said interaction region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 illustrates a medical apparatus in accordance with the invention in the form of a computed tomography apparatus.

[0038] FIG. 2 shows the patient support plate of the computed tomography apparatus of FIG. 1, with a number of integrated electrical potential sensors arranged in a two-dimensional matrix.

[0039] FIG. 3 shows the basic design of an electrical potential sensor.

[0040] FIG. 4 shows a medical apparatus in accordance with the invention in the form of a radiation therapy apparatus.

[0041] FIG. 5 shows a patient support plate or a placement mat with only one electrical potential sensor.

[0042] FIG. 6 shows the computed tomography apparatus of FIG. 1, in an embodiment wherein a belt with an electrical potential sensor is placed on the patient.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Identical or functionally identical elements in figures are provided throughout with the same reference characters. The representations in figures are schematic and not necessarily true to scale. In the exemplary embodiments of the invention, the medical apparatuses are a computed tomography apparatus and a radiation therapy apparatus which are discussed in the following and without limitation of the invention only insofar as is deemed necessary for comprehension of the invention.

[0044] The computed tomography apparatus 1 shown in FIG. 1 has a gantry 2 with a stationary part 3 and with a schematically indicated part 4 that can be rotated around a system axis 5. The part 4 is borne by means of a support (not shown in FIG. 1) such that it can rotate relative to the stationary part 3. In the exemplary embodiment of the invention, the rotatable part 4 has an x-ray system formed by an x-ray source 6 and an x-ray radiation detector 7 that are arranged opposite one another at the rotatable part 4. In the operation of the computed tomography apparatus 1, x-ray radiation 8 emanates from the x-ray source 6 in the direction of the x-ray radiation detector 7, penetrates a measurement subject and is detected by the x-ray radiation detector 7 in the form of detector measurement data or detector measurement signals.

[0045] The computed tomography apparatus 1 furthermore has a patient bed 9 to support a patient P to be examined. The patient bed 9 has a bed base 10 on which is arranged a patient support plate 11 provided to actually support the patient P. The patient support plate 11 can be displaced in a motorized fashion in the direction of the system axis 5 relative to the bed base 10 such that it, together with the patient P, can be introduced into the opening 12 of the gantry 2 for the acquisition of 2D x-ray projections of the patient P, for example in a spiral scan.

[0046] The computational processing of the 2D x-ray projections acquired with the x-ray system or, respectively, the reconstruction of slice images, 3D images or a 3D data set based on the detector measurement data or the detector measurement signals of the 2D x-ray projections takes place with an image computer 13 (schematically presented) of the computed tomography apparatus 1.

[0047] The computed tomography apparatus 1 has a computer 14 with which computer programs can be and are executed to operate and control the computed tomography apparatus 1. The computer 14 does not need to be designed as a separate computer 14, but can be integrated into the computed tomography apparatus 1.

[0048] In the exemplary embodiment of the invention, a computer program 15 that realizes the method according to the invention to control a medical apparatus (presently the computed tomography apparatus 1) is loaded into the computer 14. The computer program 15 represents a special operating mode (among others) for the computed tomography apparatus 1 and can have been loaded into the computer 14 from a portable data medium (from a CD 16 or from a memory stick, for example) or from a server 17 via a network 18 (which can be a public network and also a network internal to the clinic or hospital).

[0049] In the exemplary embodiment of the invention, a number of electrical potential sensors 20 that are arranged in a two-dimensional matrix is integrated as a contact device for the patient P into the patient support plate 11. FIG. 2 shows in a schematic view, the arrangement of the electrical potential sensors 20 inside the patient support plate 11. The arrangement of the electrical potential sensors 20 inside the patient support plate 11 is such that a coupling of the electrical potential sensors 20 to the body surface of the patient P takes place upon placement of the patient P on the patient support plate 11, such that measurement signals can be generated with the electrical potential sensors 20.

[0050] FIG. 3 shows the principle design of one of the electrical potential sensors 20 that is used in the case of the present exemplary embodiment of the invention. The electrical potential sensor 20 includes three electrodes 41 through 43 that can be, or presently already are, coupled capacitively to the body of the patient P, of which three electrodes 41 through 43 the electrodes 41 and 42 are active electrodes. The electrode 43 is a reference electrode or what is known as a “driven ground plane”. All three electrodes are provided at the patient with an insulating layer 44 through 46 and are customarily coupled to the body of the patient P across the clothing of the patient P. Difference measurement signals are generated based on the signals of the two active electrodes 41, 42.

[0051] For the present invention, it is primarily the dynamic distance variation between the body surface of the patient P and the electrodes of the electrical potential sensors 20 due to the cardiac activity of the patient P as well as the rise and fall of the ribcage as a result of breathing of the patient P that are relevant.

[0052] In the exemplary embodiment of the invention, each electrical potential sensor 20 also has electrical structural elements for signal pre-processing. The signals of the active electrodes 41, 42 are thus supplied to an instrument preamplifier 48. Furthermore, filters 49 as well as an A/D converter 50 can be provided. However, the electrical potential sensors 20 do not necessarily need to have such structural elements or all cited structural elements for signal pre-processing or for signal processing. Insofar as it is feasible in terms of measurement technology, the signals of the active electrodes can also first be directed out of the patient support plate 11 and then be processed further.

[0053] In the exemplary embodiment of the invention, the electrical potential sensors 20 are connected with a signal evaluation device that has a multiplexer 21 and a computer to evaluate the difference measurement signals. In the case of the present exemplary embodiment of the invention, the computer 14 forms the computer of the signal evaluation device. The difference measurement signals of the electrical potential sensors 20 are supplied to the computer 14 via the multiplexer 21.

[0054] The computer 14 evaluates the difference measurement signals received from the multiplexer 21, wherein in the case of the present exemplary embodiment of the invention it subjects the difference measurement signals of each electrical potential sensor 20 to a Fourier and/or a wavelet analysis in order to in particular initially identify those electrical potential sensors 20 of the matrix whose difference measurement signals or whose signal portions of the difference measurement signals have a signal energy that is typical of cardiac activity and a frequency that lies within the frequency bandwidth that is associated with a human heart (approximately 60 to 140 beats per minute).

[0055] The position of the heart of the patient P in relation to the patient support plate 11 is determined via the electrical potential sensors 20 that are identified in such a manner. In the case of the present exemplary embodiment of the invention, a cross-correlation analysis of the difference measurement signals which originate from identified adjacent electrical potential sensors 20 additionally takes place in order to determine the precise position of the heart of the patient P in relation to the patient support plate 11.

[0056] The activity of the heart of the patient is determined based on the analysis of the difference measurement signals of the identified electrical potential sensors 20 arranged near the heart of the patient P. Ideally, the cardiac cycle of the patient P or, respectively, an electrocardiogram of the heart of the patient P is determined so that trigger pulses to establish an aforementioned “pulsing windows” can be generated based on the determined cardiac cycle or, respectively, the electrocardiogram. For example, in this way the acquisition of x-ray projections of the chest region (in particular of the heart of the patient P) can be controlled, meaning that x-ray projections in which the heart of the patient P makes practically no movement are acquired only during the “pulsing window” established by the trigger pulses.

[0057] If the attitude of the heart in relation to the patient support plate 11 is determined, those electrical potential sensors 20 whose difference measurement signals are best suited to determine the breathing cycle of the patient P can moreover be better identified or located. In particular, those electrical potential sensors 20 whose difference measurement signals pertain to chest breathing and those electrical potential sensors 20 whose difference measurement signals pertain to diaphragmatic breathing can be identified or, respectively, located.

[0058] The breathing cycle pertaining to chest breathing can inasmuch be determined based on the identified electrical potential sensors 20 whose difference measurement signals pertain to the chest breathing. Ultimately, trigger signals with which at least one time period of the breathing cycle is established for acquisition of x-ray projections of the chest region of the patient P (in particular of the lungs of the patient) can be generated using the breathing cycle pertaining to chest breathing.

[0059] The breathing cycle pertaining to the diaphragmatic breathing can be determined in a comparable manner based on the identified electrical potential sensors 20 whose difference measurement signals pertain to the diaphragmatic breathing. Ultimately, trigger signals with which at least one time period of the breathing cycle for acquisition of acquisition projections of the region of the abdomen of the patient P is established can be generated using the breathing cycle pertaining to the abdominal breathing.

[0060] With regard to the computed tomography apparatus 1, the respective determined or established trigger signals can be used both for the prospective image generation method that was already described—in which x-ray projections are only acquired when optimally no movement of the torso of the patient P takes place, which movement is inherently caused by the cardiac and/or breathing activity—and for a retrospective image generation method in which, after the acquisition of the x-ray projections based on the trigger signals, those x-ray projections that were acquired at a phase in which optimally no movement of the torso of the patient that was caused by the cardiac and/or breathing activity existed are selected for an image reconstruction.

[0061] The difference measurement signals of the electrical potential sensors 20 can furthermore be used to determine the alignment, the size, the attitude of at least one arm, the attitude of at least one leg, the attitude of the torso and/or the attitude of the head of the patient P in relation to the patient support plate 11. This preferably takes place with the cooperation of the patient P in that said patient P makes corresponding movements of the corresponding body parts so that defined difference measurement signals are generated whose evaluation on the part of the computer 14 supplies the desired information.

[0062] In the case of the exemplary embodiment of the invention, based on the obtained information about the size, the alignment, the attitude of the heart, the head, the arms and the legs of the patient P in relation to the patient support plate 11 the attitude of various internal organs (such as the attitude of the lungs, of the intestine etc.) or various other tissues of the patient P (such as the spinal column, the pelvis etc.) are determined in relation to the patient support plate 11, stored, and based on this—and under consideration of the known attitude and position of the patient support plate 11 and the gantry 2 relative to one another—various body segments or scan segments of the patient P can be established or defined in relation to the patient support plate 11 and stored, in which segments image information must respectively be acquired for an imaging of an internal organ or a tissue of the patient P. A function known as an “auto-align function” is thus achieved. If the heart of the patient P should be scanned, the scan region—thus the region in which x-ray projections of the heart must be acquired from different projection directions during rotation of the x-ray system around the system axis 5—is already established or, respectively, defined, and does not need to first be determined by means of an overview scan. The same is true for the other organs and tissue of the patient P.

[0063] Furthermore, movements of the patient, such as movements of an arm, a leg, the torso or the head of the patient P in relation to the patient support plate 11,—can be determined based on the difference measurement signals and the computer 14 (in particular during an acquisition of x-ray projections), and movement artifacts can be avoided in the reconstructed images of a tissue of the patient P under consideration of the determined movements.

[0064] The computed tomography apparatus 1 can be used not only for imaging but also for planning of procedures (or also to plan a radiation therapy) in order to correlate the movement of a tissue of a patient that is to be therapeutically treated, for example with the breathing phases of said patient.

[0065] The imaging medical apparatus can moreover also be a C-arm x-ray apparatus, a PET apparatus, a SPECT apparatus or a magnetic resonance apparatus.

[0066] For a use of the electrical potential sensors in a magnetic resonance apparatus, these can also be produced from a non-magnetic metal.

[0067] Moreover, the medical apparatus can also be a radiation therapy apparatus. FIG. 4 shows such a radiation therapy apparatus 31 in a significantly schematic presentation, which apparatus 31 comprises a gantry 32 with a stationary part 33 and with a schematically indicated part 34 that is rotatable around a system axis 35, which part 34 is borne by means of a support (not shown in FIG. 4) such that it can rotate relative to the stationary part 33. The rotatable part 34 has a therapeutic x-ray source 36 and an x-ray detector 37 arranged opposite this for MeV imaging. The remaining components of the radiation therapy apparatus 31 (such as the patient bed 9, etc.) essentially correspond to the components of the computed tomography apparatus 1, which is why these are provided with the same reference characters. The therapeutic x-ray source 36 serves to charge a tissue of the patient P that is to be treated therapeutically with therapeutic x-rays that have a photon energy in the MeV range.

[0068] In the case of a radiation therapy apparatus, the trigger signals generated from the difference measurement signals of the electrical potential sensors 20 of the patient support plate 11 are used to charge the tissue of the patient P with the therapeutic x-ray radiation only when optimally no movement (caused by the cardiac or breathing activity of the patient P) of the tissue to be therapeutically treated is present and/or when the tissue to be therapeutically treated is located in a defined therapy position, such that tissue that is not to be therapeutically treated is not also charged with x-ray radiation.

[0069] In contrast to the described exemplary embodiments of the invention, the electrical potential sensors do not necessarily need to be integrated into the patient support plate. The possibility also exists to arrange the electrical potential sensors in a placement mat that can be or, respectively, is placed on the patient support plate. This is particularly advantageous for already existing medical apparatuses that can simply be retrofitted in this manner.

[0070] Also, a matrix of electrical potential sensors does not necessarily need to exist. Insofar as it is appropriate, only one electrical potential sensor can also be presented in a patient support plate or placement mat. Using the patient support plate 11, FIG. 5 illustrates this simplified design in which only one electrical potential sensor 20 is present. In this case, no multiplexer is required.

[0071] Alternatively, at least one electrical potential sensor 20 can also be arranged in or be integrated into a belt 60 that is placed on the chest of a patient P. FIG. 6 shows this embodiment of the invention according to FIG. 1. In this case, the patient support plate 11 does not need to have any electrical potential sensors. The belt is normally elastic in order to ensure a good contacting of the electrical potential sensor 20 with the body of the patient P.

[0072] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.