MAGNETIC RESONANCE SYSTEM AND METHOD FOR CONTROLLING A POWER SUPPLY FOR A SUPERCONDUCTING COIL OF THE MAGNETIC RESONANCE SYSTEM

Abstract

A magnetic resonance (MR) apparatus has an MR scanner that includes a basic field magnet, which defines a patient receiving zone and that has at least one superconducting coil that generates a basic magnetic field in the MR scanner. The MR scanner has a power supply controlled by at least one control computer of the MR apparatus for the purpose of providing electrical power to the superconducting coil. The power supply is arranged on, and may be fixedly mounted to, the basic field magnet or integrated into the basic field magnet.

Claims

1. A magnetic resonance (MR) apparatus comprising: an MR data acquisition scanner comprising a basic field magnet that defines a patient receiving zone in said MR data acquisition scanner, said basic field magnet comprising at least one superconducting coil that generates a basic magnetic field in the MR data acquisition scanner; said MR data acquisition scanner comprising a power supply that is structurally combined in the MR data acquisition scanner by being situated on or integrated into said basic field magnet, said power supply being electrically connected to said superconducting coil; and a computer configured to operate the power supply to selectively provide electrical power to said superconducting coil.

2. An MR apparatus as claimed in claim 1 wherein said power supply is fixedly mounted to said superconducting coil.

3. An MR apparatus as claimed in claim 1 wherein said power supply is comprised of materials that make said power supply ferrite-free.

4. An MR apparatus as claimed in claim 1 wherein said power supply comprises a high-current generator that provides a galvanic current of greater than 100 A to said superconducting coil.

5. An MR apparatus as claimed in claim 4 wherein said high-current generator is a power pack.

6. An MR apparatus as claimed in claim 1 wherein said power supply comprises a communication interface to said control computer in order to receive control signals from said computer that control said power supply, said communication interface being selected from the group consisting of a communication interface combined with said power supply in a unitary structure, and a communication interface that is separate from said power supply, but is in communication with said power supply, and is mounted on or in said basic field magnet.

7. An MR apparatus as claimed in claim 6 wherein said MR data acquisition scanner is installed in a shielded room, and wherein said computer is situated outside of said shielded room.

8. An MR apparatus as claimed in claim 7 wherein said computer is configured to convert control signals for said power supply into proprietary protocols.

9. An MR apparatus as claimed in claim 7 comprising an operator control console having an input device that communicates with said computer.

10. An MR apparatus as claimed in claim 7 comprising an uninterruptible power supply that provides power at least to said computer.

11. An MR apparatus as claimed in claim 9 wherein said computer is configured, upon occurrence of a power failure being detected by said computer, to control said power supply in order to ramp down a current flow through the superconducting coil, using electrical power of said uninterruptible power supply.

12. An MR apparatus as claimed in claim 6 wherein said computer is configured to perform at least one of a ramp down of current flow through said superconducting coil if an emergency criterion is fulfilled, and to ramp up or ramp down the current flow through the superconducting coil dependent on a control signal received via said communication interface.

13. An MR system as claimed in claim 1 comprising a programmable time switch configured to transmit a control signal to said power supply in order to ramp down or ramp up a current flow through the superconducting coil at programmed times.

14. An MR apparatus as claimed in claim 12 wherein said programmable time switch is integrated into one of said basic field magnet, said control unit, or said power supply.

15. An MR apparatus as claimed in claim 1 wherein said computer comprises a network interface configured to place said computer in connection with a communication network in order to receive control signals for the power supply via the network interface, and wherein said computer is configured to control the power supply dependent on the control signals received via the network interface.

16. A method for controlling a power supply for a superconducting coil of a basic field magnet of a magnetic resonance (MR) scanner, wherein the power supply is structurally combined in the MR data acquisition scanner with the basic field magnet, said method comprising: from a computer in communication with said power supply, operating the power supply in order to ramp up current through the superconducting coil when a ramp-up criterion is fulfilled; and from said computer, ramping down the current flow through the superconducting coil when a ramp-down criterion is fulfilled.

17. A method as claimed in claim 15 wherein said ramp-up criterion or said ramp-down criterion is provided via a time switch at at least one programmed time.

18. A method as claimed in claim 15 wherein at least one of said ramp-up criterion or said ramp-down criterion is provided by an external computing device situated at a source remote from an installation site of the MR data acquisition scanner.

19. A method as claimed in claim 15 comprising transmitting at least one operating parameter from said power supply, which characterizes operation of said power supply, to said computer.

20. A method as claimed in claim 18 wherein said power supply transmits said at least one operating parameter after performance of a predetermined action prescribed to said power supply by a control signal.

21. A method as claimed in claim 15 comprising providing said control computer with control signals for said power supply via a source selected from a LAN and the Internet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 schematically illustrates a magnetic resonance apparatus according to the invention.

[0031] FIG. 2 is a flowchart of an exemplary embodiment of the method according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] FIG. 1 is a schematic illustration of components of a magnetic resonance apparatus 1 according to the invention as well as components communicating with the apparatus. The magnetic resonance apparatus 1 has, as is generally known, a magnetic resonance scanner 2 situated within a shielded room 3. The magnetic resonance scanner 2 has a basic field magnet 4 in which at least one superconducting coil 5 for generating the basic magnetic field of the magnetic resonance scanner 2 is arranged. The superconducting coil 5 has a cooling device 6, possibly operating with helium as the coolant. In this case the cooling device 6 can be realized with a reduced volume of helium compared to conventional cooling devices or can even do without helium altogether.

[0033] The circumferentially running windings of the superconducting coil 5 serve to define a cylindrical patient receiving zone (not shown in further detail) into which a patient can be introduced by a patient bed 7 for the purpose of magnetic resonance imaging.

[0034] In addition to a further power supply (not shown) the magnetic resonance scanner 2 has, fixedly mounted on the basic field magnet unit 4, a power supply 8 for the superconducting coil 5, via which it is possible, when the power supply 8 is actuated accordingly, to increase (ramp up) and also decrease again (ramp down) the current flow through the superconducting coil 5 and consequently the basic magnetic field. In order for the designated value for the basic magnetic field, and therefore the designated magnetic resonance frequency, to be set exactly, the currents supplied by the power supply 8 and provided in it by a high-current generator embodied as a power pack must be set exactly. Such currents can amount to several hundred amperes, with cooling being additionally provided by passive cooling components 9. A direct-current feed voltage can be generated outside of the shielded room 3 by a voltage generator and conducted to the power supply 8 at low current levels so as to avoid high currents in the shielded room. The voltage generator is not equivalent to a power amplifier for gradient coils, which would be significantly overdimensioned. In order to monitor the operation of the power supply 8, the power supply 8 has a current measuring device 10 and a temperature sensor 11, which supply the current through the power supply 8 and the temperature of the passive cooling components 9 as operating parameters, which can also be passed on to a control computer (still to be discussed) of the magnetic resonance apparatus 1 as well as, where necessary, to external computers.

[0035] In order to minimize the effect on the magnetic resonance imaging within the shielded room 3 and particularly within the homogeneity volume of the magnetic resonance scanner 2, the entire power supply 8 is implemented as ferrite-free, which applies as well to the current measuring device 10, which makes use of shunt resistors.

[0036] The power supply 8, which may also be realized as part of the basic field magnet 4, i.e. integrated into the magnetic resonance scanner 2, can be actuated accordingly by the control computer of the magnetic resonance apparatus 1, which has a variety of components. Generally it may be said that the control computer of the magnetic resonance apparatus 1 actuates the power supply 8 in order to ramp down the current flow through the superconducting coil 5 when a ramp-down criterion is fulfilled, and to ramp up the current flow through the superconducting coil 5 when a ramp-up criterion is fulfilled.

[0037] The actuation is effected in this case by a control component 12 as a component of the control computer, which is provided on or in the basic field magnet 4 of the magnetic resonance scanner 2 and can also actuate other components of the scanner 2, for example the cooling device 6 and/or the patient bed 7, in their operation. The control component 12 receives its corresponding control signals via a communication link 13 to a control arrangement 15 of the control computer of the magnetic resonance apparatus 1 provided inside an electronics cabinet 14, the electronics cabinet 14 being provided outside of the shielded room 3 and therefore, as is generally known, a filter plate 16 being used in order to remove frequency bands, in particular around the magnetic resonance frequency, disrupting the magnetic resonance imaging or the processing by the control arrangement 15. A communication interface allowing external control of the power supply 8 is therefore created by the communication link 13 (and the control computer 12).

[0038] The control component 12 receives its control signals from a central control component 17 of the control arrangement 15 which translates, and therefore conditions, the control signals into proprietary protocols. It should be noted that an embodiment is also conceivable in which the power supply 8 receives its control signals directly from the control component 17.

[0039] The control arrangement 15 also includes further components, a computer 18, amplifiers 19 for a gradient coil array (not shown in further detail) of the magnetic resonance scanner 2 and a radiofrequency coil array (not shown in further detail) of the magnetic resonance scanner 2, transformers 20 and a main terminal 21 being shown as an example. The communication of the control component 17 with the outside world is implemented in this case by the computer 18, as is indicated by the arrow 22. The computer 18 is connected via a LAN connection 23 to an operator computing console 24 also belonging to the magnetic resonance apparatus 1, and consequently to the control device of the magnetic resonance apparatus 1. Via the operator computing console 24, an operator is able in person to exercise control locally, i.e. in particular within the institution using the magnetic resonance apparatus 1, over various components of the magnetic resonance apparatus 1, in particular also the power supply 8, for which purpose the operator computing console 24 of course has a corresponding input device 25.

[0040] In the present case, however, the computer 18 also provides a network interface 26, which permits a connection into a local communication network 27 (LAN) and, via the internet 28 as global communication network, also to a computing device 29 at the manufacturer and/or service provider end. It is also possible to use the computing device 29 associated with the manufacturer or service provider to implement a remote control of the components of the magnetic resonance apparatus 1, i.e. in particular also of the power supply 8, which in the reverse case can in turn transmit operating parameters for monitoring its activity by way of the control device of the magnetic resonance apparatus 1 to the outside, i.e. in particular to the operator computing console 24 or the computing device 29, where a corresponding information output is also to take place. It should be noted that operating parameters of the power supply 8 may also be employed within the control device of the magnetic resonance apparatus 1 itself in order to generate corresponding control signals for optimizing the operation of the power supply 8, for example to ramp more slowly if there is an imminent risk of overheating and the like. This means that the power supply 8 integrated in the magnetic resonance device 2 is also fully integrated into the control operation of the magnetic resonance apparatus 1.

[0041] Also provided on the part of the magnetic resonance apparatus 1 is furthermore a time switch device 30, which in the present case is realized within the control unit 12, but may also be realized by corresponding hardware and software components at some other location, though preferably in the basic field magnet 4 and/or the power supply 8. By way of the programmable time switch device 30 it is possible to pre-program times at which the power supply 8 is actuated in order to ramp up or ramp down the current flow through the superconducting coil 5 and consequently the basic magnetic field. The time switch device 30 is programmed by programming signals generated by the operator computing console 24 and/or of the computing device 29 on the basis of operator inputs, which programming signals are used accordingly by the control device of the magnetic resonance apparatus 1 in order to perform the programming. A programming signal therefore designates at least point in time and an action that is to be performed at that point in time. It is also possible for regularly recurring times, for example a ramp-down of the basic magnetic field every weekend, to be programmed.

[0042] Control signals for ramping up or ramping down the basic magnetic field can therefore be generated both by the operator computing console 24 and by the computing device 29 at the manufacturer or service provider end, the corresponding criterion, i.e. the ramp-down criterion or the ramp-up criterion, being fulfilled when the control signals are present; programming signals which are responsible for a corresponding programming of the time switch device 30 may additionally be generated there. Once a programmed time for a ramp-up or ramp-down is reached, the ramp-up criterion or ramp-down criterion is also fulfilled accordingly.

[0043] However, the fulfillment of the ramp-up criterion or in particular of the ramp-down criterion can also be determined based on emergency criteria that are monitored on the part of the control device of the magnetic resonance apparatus 1. For example, it can be checked within the scope of an emergency criterion whether the cooling device 6 is operational or not and/or even whether a total power failure is present. In order to enable an emergency criterion of said type, the magnetic resonance apparatus 1 furthermore has in addition an uninterruptible power supply 31, which maintains at least the control component 17 and the control unit 12 in operation even in the event of a total power failure. The electrical energy stored in the uninterruptible power supply or electrical energy provided by the latter is preferably also sufficient to enable—ultimately, therefore, to initiate (which is sufficient)—a full ramp-down operation by way of the power supply 8. A ramp-up is not necessary for the specific application scenario, so the uninterruptible power supply 31 can remain a small-dimensioned unit.

[0044] FIG. 2 shows a flowchart of an exemplary embodiment of the method according to the invention.

[0045] In a step S1, the control device of the magnetic resonance apparatus 1 continuously monitors for the possible occurrence of a ramp-up criterion when the basic magnetic field is deactivated and for the possible occurrence of a ramp-down criterion when the basic magnetic field is activated. The input data evaluated for this purpose comprises control signals 32, which can originate, for example, from one of the computing devices 24 and/or 29, trigger signals 33 of the time switch device 30 and also operating data 34 of the magnetic resonance system in order for example to enable a check to be made for the occurrence of an emergency criterion or whether an emergency criterion has ceased to be fulfilled.

[0046] If the ramp-up criterion or ramp-down criterion is fulfilled in step S1, in a step S2, the control device of the magnetic resonance system 1 actuates the power supply unit 8 accordingly in order to ramp down or ramp up the current flow through the superconducting coil 5 such that the basic magnetic field is deactivated or activated for a corresponding period of time. During this time, as indicated by step S3, a constant monitoring of the activity of the power supply 8 based on the evaluation of its operating parameters can take place on the part of the control device of the magnetic resonance system 1. An information output in relation to the operating parameters of the power supply 8 for the superconducting coil 5 can also be generated by the operator computing console 24 or the computing device 29. Once the ramp-down or ramp-up operation has been successfully terminated, the corresponding other criterion is monitored in step S1.

[0047] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the Applicant to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of the Applicant's contribution to the art.