Method and device for calculating a mass on a patient table, patient table system and medical system

Abstract

The invention relates to the calculation of a mass or weight on an electrically movable patient table. For this purpose, the frequency response of a drive system for the patient table is determined, an asymptote for the frequency response is determined in a given frequency range, and the mass or weight on the patient table is calculated from this asymptote.

Description

[0001] The present invention relates to a method and a device for calculating a mass on a patient table, in particular an electrically movable patient table. The present invention further relates to a patient table system and a medical system comprising such a patient table system.

[0002] Although the present invention is preferably described below in connection with a patient table for an angiography system, the present invention is not limited thereto. Rather, the basic principle of the invention can also be applied to other systems. The principle of the invention enables the mass or weight of objects on electrically movable support components to be determined based on mass inertia.

[0003] Knowing a patient's weight is important for numerous medical applications. For example, a patient's weight may be needed to adjust the dosage of a medication or to adjust the parameters of a medical device to a patient. If no current data on the patient's weight is available, this weight must be determined before a patient can be treated. For example, the patient's weight is also required to configure an angiography system and, if necessary, to determine the correct dose for a contrast agent, etc.

[0004] Angiography systems, like many other medical devices, may include a patient table on which the patient can be positioned. This patient table can be moved by one or more electric drives. For example, the patient table can be height-adjustable and / or moved laterally in one or more spatial directions. Rotational movements of the patient table are also possible if necessary.

[0005] To control an electrically driven, adjustable patient table, suitable control components (NCU, numerical control unit) can be used, such as Sinumerik one, NCU 1750 from Siemens or other control components that have a measuring function for determining the behavior of an axis and / or from which data from a Bode diagram can be derived. In addition to familiar tasks for control and motion control, such units can also already have implemented measuring and optimization functions. One such optimization function is so-called "Auto Servo Tuning". This function can be used to display the mechanical behavior of a mechatronic axis from the drive's perspective in the frequency domain. The result can be displayed, for example, in the form of a Bode diagram. In particular, the system's natural frequencies can also be determined automatically.

[0006] Based on this, it is an object of the present invention to determine the mass or weight of a patient on an electrically driven patient table. In particular, it is an object to determine the mass of a patient on an electrically driven patient table using information from the electrical drive system and / or without measuring the weight (or reading in a weight).

[0007] To this end, the present invention provides a method and a device for calculating a mass on an electrically movable patient table, a patient table system, and a medical system having the features of the independent patent claims. Further advantageous embodiments are the subject of the dependent patent claims.

[0008] According to a first aspect, a method for calculating a mass on an electrically movable patient table is provided. The method comprises a step for determining a frequency response of a drive system for the patient table. This can in particular be the frequency response of a speed controller in the drive system. The frequency response can in particular be determined during a movement of the patient table with the mass to be determined. The frequency response can be determined, for example, using a control interface of the drive system. Furthermore, the method comprises a step for determining an asymptote in the determined frequency response. The asymptote can in particular be determined in a predetermined frequency range of the frequency response. In principle, any suitable mathematical or numerical methods can be used for this purpose.The method further comprises a step of calculating the mass on the patient table. The calculation of the mass on the patient table can be carried out, in particular, using the previously determined asymptote.

[0009] According to a further aspect, a device for calculating a mass on an electrically movable patient table is provided. The device is intended to carry out the method according to the invention. The device comprises a frequency response determination module and a computing unit. The frequency response determination module is intended to determine a frequency response of a drive system for the patient table. The frequency response can, in particular, be the frequency response of a speed controller in the drive system. The computing unit is intended to determine an asymptote in a curve of a predetermined frequency range of the determined frequency response. Furthermore, the computing unit is intended to calculate the mass on the patient table. In particular, the computing unit is intended to determine the mass on the patient table using the predetermined asymptote.

[0010] According to a further aspect, a patient table system is provided. The patient table system comprises a patient table, an electric drive system, a control interface, and an analysis interface. The patient table system can be understood as a mechatronic system. The patient table is designed to accommodate a patient. For example, the patient can be placed on the patient table for treatment or examination. The electric drive system is designed to move the patient table mechanically. For this purpose, one or more drive elements for a lateral and / or rotational movement of the patient table can be provided, for example. A drive element can in particular comprise a motor or an electric drive and, if appropriate, a gear. The control interface is designed to determine a frequency response of the drive system for the patient table.The analysis interface is designed to determine an asymptote in a curve of the determined frequency response. In particular, the analysis interface is designed to determine the asymptote in a predetermined frequency range of the determined frequency response. Furthermore, the analysis interface is designed to calculate a mass on the patient table. In particular, the analysis interface is designed to calculate the mass on the patient table using the predetermined asymptote. The control interface and / or the analysis interface can, for example, be integrated into a device for controlling the electric drive system. However, it is also possible to implement the control interface and / or the analysis interface outside the device for controlling the electric drive system.In particular, it is also possible, for example, to implement the functionality of the control interface within the control system for the electric drive system, to transmit the information about the frequency response, resonance frequency and / or other characteristic data via a suitable communication connection to a separate analysis interface.

[0011] According to yet another aspect, a medical system is provided. The medical system comprises a patient table system according to the invention. Furthermore, the medical system can comprise a dosing device. The dosing device is designed to set a dosage for a medication. In particular, the dosage can be set using the calculated mass on the patient table. Additionally or alternatively, the medical system can comprise a medical, in particular radiological, examination device. The radiological examination device is designed, for example, to set a radiation output using the calculated mass on the patient table.

[0012] The present invention is based on the realization that the weight of a patient is of great importance for numerous medical applications. Furthermore, the present invention is based on the realization that patients are often placed on an electrically adjustable patient table during an examination or treatment. Based on these considerations, one idea of ​​the present invention is to create a concept which, using an electrically adjustable patient table, can determine the weight on the patient table, i.e. the mass of the patient on the table. For this purpose, the invention uses information which is already available via the electrical drive system of the patient table, in particular the control system used therein, or which can be easily obtained with only minor modifications to the system.

[0013] In particular, the inventive concept allows the mass on the patient table and thus the patient's weight to be determined without a load cell or similar device and / or without reading weight data via a data interface. The mass on the patient table is preferably determined exclusively based on the principle of mass inertia and does not take gravitational forces into account.

[0014] The mass to be determined on the patient table can be any (variable) mass, in particular a mass that is temporarily arranged on the patient table. This mass can in particular be a removable or detachable object, such as a person, in particular a patient. The object or person can in principle be arranged in any area and / or in any position (i.e., with any center of mass) on a table surface of the patient table.

[0015] To determine the mass on a patient table, the patient table and its drive system are considered a multi-mass oscillator, in particular, for example, a two-mass oscillator. Due to elasticities such as a coupling between the motor and a threaded spindle during a translational movement of the tabletop of the patient table, the system can, in the simplest case, be considered a two-mass oscillator, in which the first mass of the patient table with the patient is variable, while the (intermediate) second mass (patient table without patient) can be considered constant. For the following description, the mass of the patient table with the patient is referred to as the load mass m_L and the intermediate second load is referred to as the motor mass m_M.

[0016] By modeling an electrically movable patient table as a multi- or dual-mass oscillator, it is possible to determine the load mass by analyzing the frequency response and, if necessary, further considering known system components (e.g., the motor mass). In this context, it is also advantageous that modern control systems generally already have suitable functionalities for determining the frequency response of the drive system and providing corresponding data on the frequency response. This data from the drive system's control system can therefore be used to quickly and easily determine the load mass and thus the mass on the patient table.

[0017] On the basis of the determined frequency response, as it can be provided, for example, by a control interface for the drive system of the patient table, characteristic properties such as phase responses, resonance frequencies and / or absorber frequencies or similar can be determined. In principle, any suitable analysis method is possible for this purpose. For example, such information can be determined by numerically evaluating the data from the frequency response. In particular, it is possible, for example, to determine an asymptote of the frequency response in a predetermined range of the frequency response, i.e. an approximately linear curve, in particular for the amplitude of the frequency response. This can also be done, for example, using a suitable numerical or mathematical method.

[0018] Since the frequency response, particularly the amplitude of the frequency response and an asymptote in this range, varies significantly depending on the load mass and thus the patient weight, especially for relatively low frequencies, for example, for a frequency range between zero and a predetermined cutoff frequency, the patient weight can be determined from the properties in such a range of the frequency response, especially at relatively low frequencies. Thus, a relatively simple analysis of the frequency response allows for the calculation of the patient's weight on the patient table.

[0019] The analysis of the frequency response, in particular the determination of an asymptote in the frequency response and the calculation of the mass on the patient table, can be performed using any suitable analysis interface. In particular, for example, the functionalities of the control interface for determining the frequency response for the drive system and the functionalities for evaluating the frequency response and calculating the mass on the patient table can be combined in a common device. Alternatively, it is also possible to transfer the frequency response data upstream of the control interface to a separate analysis interface via a suitable communication connection, such as a data bus or similar.

[0020] The asymptote is determined over a predefined frequency range. The frequency range can be determined using suitable measures (e.g., user interface / UI or data interface, etc.). The asymptote refers to the total moment of inertia of the patient table including the drive system.

[0021] According to one embodiment, the mass on the patient table is calculated using previously stored reference data. For this purpose, the reference data can be stored, for example, in a suitable storage device, for example a reference data memory or similar, and made available for calculating the mass on the patient table. For example, the reference data can be determined in an initialization phase. Such an initialization phase can, for example, be carried out during a start-up procedure for the patient table system or once before its commissioning. Furthermore, it is also possible to carry out such an initialization phase later, after commissioning and / or during operation, for example after a modification to the patient table. For this purpose, the initialization phase can, for example, be triggered or executed manually or automatically after a modification is detected.Additionally or alternatively, it is also possible to store reference data persistently. This may make it unnecessary to determine reference data, for example with each restart. By using stored reference data, the frequency with which reference data is determined can be reduced, for example. The reference data can be generated during a reference measurement of the frequency response. In particular, reference data can be generated during a reference measurement of the frequency response when the patient table is moving without the mass to be determined. However, while the reference data is being determined, other attachments and / or additional components may be attached to the patient table. In particular, attachments and / or additional components may be attached that are also attached to the patient table during the mass determination.The mass can be calculated, for example, by determining the deviation between the determined asymptote from the frequency response with the mass on the patient table and a reference asymptote. Such a reference asymptote can be determined, for example, based on the reference measurement. In this way, the calculation of the mass on the patient table can be carried out very easily. In particular, such a method places only minimal demands on the hardware for calculating the mass.

[0022] According to one embodiment, the initialization phase can be performed during a startup process. Additionally or alternatively, it is also possible to perform the initialization phase after attaching or removing an attachment to the patient table or after another modification to the patient table. Through such initialization, the system can be adapted to its current configuration. Thus, the system can be very easily recalibrated after a modification in order to determine correct data for the patient's mass. Furthermore, repeated, particularly regular, initialization can also take aging effects into account.

[0023] According to one embodiment, the mass on the patient table is calculated using a model for a multi-mass oscillator. In particular, the calculation can be performed using a two-mass oscillator, wherein the two-mass oscillator is formed from a first mass of the drive system (motor mass) and a second mass of the patient table (load mass). Such modeling enables a very good and easy-to-use representation for determining a mass on the patient table. In particular, existing models for the mathematical and physical relationships of such a multi- or two-mass oscillator can thus be used.

[0024] According to one embodiment, the predetermined frequency range in which the asymptote is determined has an upper limit frequency that is lower than a resonant frequency of the drive system. Particularly when modeled as a two-mass oscillator, there is significant variation in this frequency range depending on the load on the patient table. Therefore, considering this frequency range is very well suited for analyzing the mass on the patient table.

[0025] According to one embodiment, the method further comprises a step of outputting the calculated mass, in particular outputting the calculated mass on a display device. Additionally or alternatively, the calculated mass can also be output to a processing device. Such a processing device can, for example, then automatically make adjustments or determine and output recommendations for suitable settings. Such settings can, for example, include the dosage of a medication or a setting on another device, in particular a medical device, such as a radiological examination device.

[0026] According to one embodiment, the method comprises a step of calculating a dosage for a medication using the calculated mass on the patient table. The calculated dosage of the medication can then, for example, be automatically set as a preselected default setting on another medical device. Alternatively, the calculated dosage can also be displayed to a user on a display device.

[0027] According to one embodiment, the method comprises a step of setting an operating parameter for a medical device. In particular, an operating parameter can be set on a medical device, for example, a radiological examination device, using the calculated mass on the patient table.

[0028] Automatically determining a suitable dosage for a medication and adjusting the settings of a medical device based on the calculated patient weight enables rapid configuration of the required parameters. Furthermore, this can prevent potential errors in calculating operating parameters and / or entering them into another device through automatic transmission. For this purpose, suitable communication interfaces, such as a data bus or similar, can be provided between a device for determining the dosage or a suitable operating parameter and other medical components.

[0029] According to one embodiment, the patient table can comprise a multi-tilt patient table, in particular a patient table for an angiography system. Such patient tables already have an electric drive system as standard and are therefore suitable for determining a mass on the patient table based on a frequency response. This is particularly advantageous because, especially for angiography applications, a current, correct patient weight is always required.

[0030] According to one embodiment, the mass on the patient table is calculated without data from a weight sensor. A weight sensor can be any sensor component that determines the mass on the patient table based on gravity. Such a weight sensor can be a load cell or similar device, for example. Furthermore, the mass on the patient table can also be calculated without data from an external scale or another system that determines data based on weight. In other words, the mass on the patient table can be calculated exclusively based on the effects of mass inertia.

[0031] In the following detailed description of the figures, non-limiting embodiments with their features and further advantages are discussed with reference to the drawing. Fig. 1: a schematic representation of a medical system with a patient table system according to an embodiment; Fig. 2 : a schematic representation of a frequency response of a drive system for a patient table using the example of a two-mass oscillator according to an embodiment; Fig. 3 : a schematic representation illustrating the position of asymptotes in the frequency response for different patient weights; Fig. 4: a schematic representation of a block diagram of a device for determining a weight on a patient table according to an embodiment; and Fig. 5: a flowchart illustrating a method for calculating a mass on a patient table according to one embodiment.

[0032] In the following, the invention is described in more detail using exemplary embodiments in conjunction with the figures. Description of embodiments

[0033] In this disclosure, the solution to the problem is described with reference to the method and / or the device or system. Features, advantages, or alternative embodiments mentioned therein are also to be transferred to the other claimed subject matter, and vice versa. In other words, the subject claims (which are directed, for example, to a device, a system, or a computer program product) can also be developed with the features described or claimed in connection with the method, and vice versa. The corresponding functional features of the method are implemented by corresponding subject modules, in particular by hardware modules or microprocessor modules, of the system or product, and vice versa.The preferred embodiments of the invention described in connection with the method are not explicitly repeated for the device, but can also be applied within the scope of the device and vice versa. In general, in computer science, a software implementation and a corresponding hardware implementation (e.g., as an embedded system) are equivalent. For example, a method step for "storing" data can be carried out using a memory unit and corresponding instructions for writing data to the memory. To avoid redundancy, the device is therefore not explicitly described again, although it can also be used in the alternative embodiments described with reference to the method. In principle, the claimed device is designed to carry out the claimed method.

[0034] Fig. 1 shows a schematic representation of a patient table system 1 for a medical system according to one embodiment. In addition to the patient table 10, the patient table system 1 can comprise an electric drive system 13 as well as a control interface 14 and an analysis interface 15. The patient table 10 can comprise a first part 11, for example a lower part, and a second part 12, for example an upper part with a tabletop 12a. The first part can, for example, stand on the floor or be in contact with a solid surface or another solid component in any other way. For example, a patient 19 or, in principle, any other object can be placed or attached in some other way on the tabletop 12a of the upper part 12.

[0035] The patient table 10 can, in principle, be any electrically or electromechanically adjustable table suitable for accommodating an object, in particular a patient 19. For example, the patient table can be an electrically adjustable table for an angiography system or the like. The patient table 10 can, for example, be moved laterally in one or more directions by means of an electrical drive system 13 and / or rotated about one or more axes. Fig. In the embodiment shown in Figure 1, a table top 12a of the upper part 12 can be varied in height, for example, by means of an electric drive system 13. However, this is only an example to illustrate the basic principle of the invention and does not represent a limitation of the present invention.

[0036] The second part 12 is adjustable relative to the first part 11, for example, by means of the electric drive system 13. For example, the second part 12 can be extended or retracted using an electric motor and a gear. A control interface 14 can be provided to control the electric drive system 13. For example, the control interface 14 can be a SIMULINK ONE, NCU 1750 from Siemens. In principle, however, other suitable control interfaces 14 are also possible, in particular control interfaces 14 that have the option of improving the frequency response described below.

[0037] In addition to the basic functionalities for controlling the electric drive system 13, the control interface 14 can also provide additional applications. In particular, the control interface 14 can also determine a frequency response for controlling the electrical adjustment of the patient table 10. This frequency response can, in particular, be the frequency response of a speed controller for the control. This frequency response can be used for internal processing within the control interface 14. Furthermore, the frequency response can also be output to other components, such as an analysis interface 15, via a suitable communication connection, for example, a data bus or similar.

[0038] Due to elasticities, such as the coupling between a motor and a threaded spindle in the electric drive system 13, the patient table 10 can be modeled, for example, as a two-mass oscillator. For this purpose, the first part 11 forms a first region up to the electric drive system 13, and the second part 12 between the electric drive system 13 and the tabletop 12a with the patient 19 forms a second region. Accordingly, the tabletop 12a with the patient 19 can be considered a first mass (load mass, m_L), and the mass on the electric drive system 13 can be considered a second mass (motor mass, m_M). However, the basic mathematical and physical relationships of such a two-mass oscillator are assumed to be known at this point and therefore will not be described in detail.

[0039] In Fig. Figure 2 schematically illustrates a frequency response for such a patient table 10 using the example of a dual-mass oscillator, such as can be determined, for example, using a control interface 14 for the electric drive system 13 of the patient table 10. The upper section shows the amplitude versus frequency, and the lower section shows the phase versus frequency.

[0040] As in Fig. As can be seen in Figure 2, the amplitude initially decreases and reaches a minimum at a first frequency f_T. This first frequency f_T corresponds to a so-called absorber frequency. The amplitude then increases up to a second frequency f_Res and then decreases again. The second frequency f_Res corresponds to a resonance frequency. The first section up to the absorber frequency f_T and the third section starting at the resonance frequency f_Res can each be approximated by an asymptote of 110 and 120, respectively.

[0041] Studies have shown that, with knowledge of the system properties of the patient table system 1, the weight or mass of a patient 19 on the tabletop 12a can be determined from this frequency response, in particular from the amplitude of the frequency response. For this purpose, the frequency response up to the first frequency f_T or an asymptote 110 approximating this frequency response can be evaluated.

[0042] For a system such as a patient table system 1, consideration of the frequency range up to approximately 1000 Hz is sufficient. In principle, however, depending on the application and system properties, different frequency ranges or bandwidths may also be suitable. For example, a bandwidth of up to 5000 Hz or 10 kHz can be selected. However, depending on the application, narrower bandwidths, for example 500 Hz, 400 Hz, 200 Hz or 100 Hz, may also be suitable. In one embodiment, for example, the frequency response can be discretely sampled with a bandwidth of approximately 1000 Hz with a predetermined number of sampling points, for example 1023 sampling points. Depending on the application and the desired accuracy, different settings with regard to bandwidth and / or number of sampling points are also possible. For example, depending on the application, more sampling points, for example 2048, 4096, or more, may be possible.Depending on the application, fewer support points can also be selected, for example 512, 256 or 128 support points.

[0043] The frequency response, as it can be determined, for example, using a suitable application within the control interface 14, can then be evaluated to draw conclusions about the mass of the patient 19 on the tabletop 12a. On the basis of the two-mass oscillator already mentioned, for example, the amplitude curve in a frequency range below the first frequency f_T can be evaluated. In particular, an asymptote 110 can be determined in this frequency curve. For this purpose, an offset and, if applicable, a gradient of this asymptote 110 can be determined by appropriate processing of the frequency response. The mass or weight of the patient 19 on the tabletop 12a can then be calculated from the frequency response and, in particular, from the asymptote 110, if necessary taking other system properties into account.

[0044] For example, during commissioning and / or during an initialization phase, relevant system properties, and in particular a frequency response, can initially be determined for the patient table system 10 without patient 19. For example, a reference asymptote can be determined during such an initialization. If the patient table 10 is then operated with a patient 19, the reference asymptote can be compared with another asymptote (reference symptom) that was determined for the patient table 10 with the patient 19. The mass of the patient 19 can thus be deduced from the offset between the reference asymptote without patient 19 and the asymptote during operation with patient 19. If necessary, further scaling or calibration parameters can be taken into account in order to deduce the mass or weight of the patient 19 from the offset of the asymptote.

[0045] Fig. 3 shows a schematic representation of an amplitude-frequency diagram with several asymptotes 111 to 113. For example, the lower asymptote 111 can be a reference asymptote that was determined without patient 19. For a patient of medium weight, for example, an asymptote 112 can result that is slightly shifted compared to the reference asymptote 111. With increasing weight, the asymptote can shift further, so that, for example, an asymptote 113 can result in a particularly heavy patient. Thus, by evaluating the asymptote curve, comparing it with an initial reference asymptote 111 and, if necessary, applying a suitable scaling, the mass or weight of patient 19 on the patient table system 10 can be calculated.

[0046] By performing a reinitialization, the patient table system 1 can be readjusted as needed. For example, during commissioning, for example, on the morning of a workday, an initialization phase can be performed to determine a reference asymptote 111, which can be used until a new initialization or until the patient table system 1 is switched off. In principle, however, other concepts for selecting the times for determining the reference asymptote 111 are also possible.

[0047] For example, even when the patient table system is modified, for example when additional components are added or removed to the patient table 10, a new initialization can be carried out to determine a new reference asymptote 111.

[0048] Fig. Figure 4 shows a schematic representation of a block diagram of a device 2 for determining a mass on an electrically movable patient table 1. The patient table 1 and the drive system 13 can, for example, be the components already described above or comparable components. In this respect, the statements made in this context also apply to the embodiment in Fig. 4.

[0049] The device 2 for determining the mass on the patient table 1 comprises a frequency response determination module 21 and a computing unit 22. The frequency response determination module 21 and the computing unit 22 can either be designed as separate components or, alternatively, implemented in a common unit. Analogous to the previous embodiments, the frequency response determination module 21 or its functionality can also be implemented in a control interface 14 or a control unit for the drive system 13.

[0050] The frequency response determination module 21 can determine a frequency response of the drive system 13 for the patient table 1 in accordance with the above explanations. In particular, the frequency response can be determined during a movement, for example, raising and / or lowering the tabletop 12a of the patient table. For this purpose, control signals and / or sensor-detected measured values, such as electrical currents and / or voltages, can be evaluated. In principle, any conventional or existing or even novel methods can be used for this purpose.

[0051] The data of the determined frequency response are then received by the computing unit 22 of the device 2 for determining the mass and can be evaluated. In particular, the computing unit can determine an asymptote in a predetermined frequency range of the determined frequency response and, using this determined asymptote, calculate a mass on the patient table 10. This can be done, in particular, in accordance with the above explanations, for example, based on a modeling of a two-mass oscillator. The calculated mass can then be output by the computing unit 22.

[0052] To implement the functionality of the frequency response determination module 21 and the computing unit 22, one or more processors can be provided, for example. Furthermore, program code can be provided, for example, by one or more memory units communicatively coupled to the processor(s), which, when executed by the processor(s), executes the corresponding functionalities. Furthermore, any suitable interfaces for wired and / or wireless data exchange can be provided for data exchange.

[0053] The determined data for the mass or weight of the patient 19 on the tabletop 12a of the patient table 10 can be displayed to a user, for example, on a display device 31. The user can then, for example, read the patient's weight and take it into account in the further treatment of the patient. If necessary, further processing of the data relating to the patient weight can also take place within the display device 31. Alternatively, the preprocessing can also be implemented in the computing unit 22. In this case, the computing unit 22 can be designed to calculate and output, based on the determined mass on the patient table 10, a specification for a setting on another medical device, a specification for other technical measuring or examination systems, and / or other parameters relating to the weight on the patient table 10.For example, based on the determined patient weight, recommendations for configuring further settings on other medical devices such as an X-ray machine and / or for a dosage of medication or similar can be calculated and displayed.

[0054] Additionally or alternatively, it is also possible to provide the determined mass or weight of the patient 19 to a processing device 32, which can then automatically configure further (medical) devices. For example, a setting for the dosage of a medication can be automatically made based on the determined patient weight. Such a dosage can either be applied directly and automatically or initially set as a recommendation on the corresponding medical device. This recommendation can then be confirmed by a user, for example a physician, before the setting is finally applied.

[0055] In addition, other medical devices, such as a radiological examination device such as an X-ray machine, can also be configured based on the determined patient weight. Here, too, the setting can either be configured automatically or initially provided as a recommendation and only applied after further user acceptance.

[0056] Fig.5 shows a flowchart underlying a method for calculating a mass, in particular the mass of a patient 19 on an electrically loadable patient table 10 according to one embodiment. The method can, in principle, comprise any steps that may be suitable for implementation in connection with the previously described embodiments. Similarly, any components suitable for implementing the method described below can also be provided in the previously described embodiments with the patient table 10.

[0057] In a step S1, the frequency response of a drive system 13 for the patient table 10 can first be determined. The frequency response, in particular the amplitude for such a frequency response, can be determined, for example, using a frequency response determination module 21 or an application in a control interface 14 for the drive system 13. To determine the frequency response, the patient table 10 can be moved by means of the drive system 13. For example, the tabletop 12a of the patient table can be moved up, down, and / or sideways.

[0058] In step S2, an asymptote 110 can then be determined in the course of a predetermined frequency range of the determined frequency response. In particular, such an asymptote 110 can be determined in a frequency range up to a predetermined cutoff frequency. Determining the asymptote 110 can, for example, include determining an offset and / or a slope of the asymptote.

[0059] In step S3, a value for a mass on the tabletop 12a of the patient table system 10 can be calculated. The mass is calculated in particular using the asymptote 110 previously determined in step S2. Previously stored reference data can also be used for this purpose, if necessary. This reference data can be provided, for example, using a storage device designed for this purpose. The reference data can be determined beforehand, for example, during an initialization phase or a calibration process. The mass can be determined in particular on the basis of a model for a two-mass oscillator. A first mass forms, for example, a first part 11 up to the drive system 13, and a second part 12 is formed by the area between the drive system 13 and the tabletop 12a.

[0060] In summary, the present invention relates to the calculation of a mass or weight on an electrically movable patient table. For this purpose, the frequency response of a drive system for the patient table is determined, an asymptote for the frequency response is determined in a predetermined frequency range, and the mass or weight on the patient table is calculated from this asymptote. The mass is calculated without a weight sensor and is based solely on the effects of mass inertia, which are determined, in particular, exclusively from data and / or functions of the control system for the patient table.

[0061] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

Claims

[1] Method for calculating a mass on an electrically movable patient table (10), comprising the steps: - determining (S1) a frequency response of a drive system (13) for the patient table (10) when the patient table (10) moves with the mass to be determined; - determining (S2) an asymptote in a course of a predetermined frequency range of the determined frequency response; and - Calculating (S3) the mass on the patient table (10) using the previously determined asymptote. [2] Method according to claim 1, wherein the calculation (S3) of the mass on the patient table (10) is carried out using reference data determined and / or stored in an initialization phase, wherein the reference data are generated during a reference measurement of the frequency response during movement of the patient table (10) without the mass to be determined, and wherein the calculation (S3) of the mass is carried out by determining a deviation between the determined asymptote and a reference asymptote which is determined on the basis of the reference measurement. [3] Method according to the immediately preceding claim 2, wherein the initialization phase is carried out during a start-up process and / or after attaching or removing an attachment to the patient table (10). [4] Method according to one of the preceding claims 1 to 3, wherein the calculation (S3) of the mass on the patient table (10) is carried out using a model for a multi-mass oscillator, wherein the multi-mass oscillator is formed from at least a first mass of the drive system (13) and a second mass of the patient table (10). [5] Method according to one of the preceding claims 1 to 4, wherein the predetermined frequency range in which the asymptote is determined has an upper limit frequency which is lower than a resonance frequency of the drive system. [6] Method according to one of the preceding claims 1 to 5, comprising a step of outputting the calculated mass on a display device (31) and / or to a processing device (32) for evaluating the calculated mass. [7] Method according to one of the preceding claims 1 to 6, comprising a step of calculating a dosage for a medicament using the calculated mass on the patient table (10). [8] Method according to one of the preceding claims 1 to 7, comprising a step of setting an operating parameter for a medical device using the calculated mass on the patient table. [9] Method according to one of the preceding claims 1 to 8, wherein the patient table (10) is a multi-tilt patient table and / or comprises a patient table for an imaging system, in particular for an angiography system. [10] Method according to one of the preceding claims 1 to 9, wherein the calculation (S3) of the mass on the patient table (10) is carried out without data from a weight sensor, in particular a load cell, and without data from an external scale. [11] A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any one of claims 1 to 10. [12] Device (2) for determining a mass on an electrically movable patient table (10), which is intended to carry out a method according to the preceding method claims, comprising: - a frequency response determination module (21) intended for determining a frequency response of a drive system (13) for the patient table (10); - a computing unit (22) which is intended to determine an asymptote in a course of a predetermined frequency range of the determined frequency response and which is intended to calculate the mass on the patient table (10) using the previously determined asymptote. [13] Patient table system (1), with: - a patient table (10) designed to accommodate a patient (19); - an electric drive system (13) designed to mechanically move the patient table (10); - a control interface (14) to a control device which is designed to determine a frequency response of the drive system (13) for the patient table (10); and - an analysis interface (15) to an analysis device which is designed to determine an asymptote in a course of a predetermined frequency range of the determined frequency response and to calculate a mass on the patient table (10) using the previously determined asymptote. [14] Patient table system (1) according to claim 13, comprising an output device which is designed to output a value for the determined mass on the patient table (10) on a display device (31) and / or to an external processing device (32). [15] Medical system, with a patient table system (1) according to claim 13 or 14 and a dosing device configured to set a dosage for a medicament using the calculated mass on the patient table (10). [16] Medical system, with a patient table system (1) according to claim 13 or 14 and a radiological examination device, wherein the examination device is designed to adjust a radiation power using the calculated mass on the patient table.

Images