# US 10,768,247 B2 · System, apparatus and method for achieving scanning safety for a magnetic resonance conditionally safe implant

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- Number: US 10,768,247 B2
- Document ID: US10768247B2
- Status: Granted
- Kind: B2
- Application number: 16/118,674
- Filed: 2018-08-31
- Published: 2019-03-07
- Granted: 2020-09-08
- Earliest claimed: 2017-09-01
- Assignees: Siemens Healthcare GmbH
- Applicants: Siemens Healthcare GmbH
- Inventors: Jianzhang Jia; Jun Wang
- Web page: https://patentgrep.com/patent/US10768247B2

## CPC

- G01R 33/288: {Provisions within MR facilities for enhancing safety during MR, e.g. reduction of the specific absorption rate [SAR], detection of ferromagnetic objects in the scanner room}
- G01R 33/543: {Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription (G01R33/546 takes precedence)}
- H03F 1/52: Circuit arrangements for protecting such amplifiers {(monitoring arrangements G01R31/28; increasing reliability in communication systems, e.g. using redundancy H04B1/74)}
- H03F 3/19: with semiconductor devices only
- H03F 3/21: with semiconductor devices only {(H03F3/245 takes precedence)}
- G01R 33/285: {Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR}
- G01R 33/3614: {RF power amplifiers}
- G01R 33/3852: {Gradient amplifiers; means for controlling the application of a gradient magnetic field to the sample, e.g. a gradient signal synthesizer}
- H03F 2200/321: Use of a microprocessor in an amplifier circuit or its control circuit
- H03F 2200/426: the amplifier comprising circuitry for protection against overload
- H03F 2200/451: the amplifier being a radio frequency amplifier
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H03F: AMPLIFIERS

## Abstract

In a system, apparatus and method for achieving scanning safety for a magnetic resonance conditionally safe implant, an FPO processor converts an RF power signal received from an RF power sensor of an MR scanner into an RF power parameter, and converts a gradient power signal received from an MR gradient power sensor of the MR scanner into a gradient power parameter. Upon detecting that the RF power parameter exceeds an RF power limit value or/and the gradient power parameter exceeds a gradient power limit value, the FPO processor sends a shutdown signal, to shut down an RF power amplifier or/and a gradient power amplifier in the MR scanner. The MR scanner is thereby enabled to realize the FPO mode, without altering MR scanner software, and the workload is small and easy to carry out.

## Claims

### Claim 1

A system for achieving scanning safety for a magnetic resonance (MR) conditionally safe implant, said system comprising:
an MR scanner comprising a radio-frequency (RF) power amplifier and an RF sensor that generates an RF power signal representing RF power emitted by said RF power amplifier, and a gradient power amplifier and a gradient power sensor that emits a gradient power sensor signal representing gradient power emitted by said gradient amplifier;
a fixed parameter option (FPO) processor configured to operate the MR scanner in an FPO mode in order to comply with requirements for safely scanning a subject having a conditionally safe implant therein;
said FPO processor comprising an interface that receives said RF power signal and said gradient power signal, said FPO processor being configured to convert said RF power signal into an RF power parameter and to convert said gradient power signal into a gradient power parameter;
said FPO processor being configured to determine when at least one of said RF power parameter exceeds an RF power limit value or said gradient power parameter exceeds a gradient power limit value;
said FPO processor being configured, when said RF power parameter exceeds said RF power limit value, to emit a shutdown signal that causes operation of said RF power amplifier to be discontinued; and
said FPO processor being configured, when said gradient power parameter exceeds said gradient power limit value, to emit a shutdown signal that causes operation of said gradient power amplifier to be discontinued.

### Claim 2 (depends on 1)

A system as claimed in claim 1 comprising a controller configured to control operation of said RF power sensor, said gradient power sensor, said RF power amplifier and gradient power amplifier, said controller comprising a switch in a series connection path between said controller and said radio-frequency power amplifier, said gradient power amplifier, and wherein said controller is configured to receive said shutdown signal from said FPO processor in order to control said switch to discontinue said operation of at least one of said radio-frequency power amplifier and said gradient power amplifier.

### Claim 3 (depends on 1)

A system as claimed in claim 1 wherein said RF power sensor is structurally independent of said radio-frequency power amplifier.

### Claim 4 (depends on 1)

A system as claimed in claim 1 wherein said RF power sensor is integrated in said radio-frequency power amplifier.

### Claim 5 (depends on 1)

A system as claimed in claim 1 wherein said gradient power sensor is structurally independent of said gradient power amplifier.

### Claim 6 (depends on 1)

A system as claimed in claim 1 wherein said gradient power sensor is integrated in said gradient power amplifier.

### Claim 7 (depends on 1)

A system as claimed in claim 1 wherein:
said FPO processor is configured to convert said RF power signal into said RF power parameter so that said RF power parameter comprises an RF power peak value and a mean value calculated from said RF power signal, and wherein said RF power limit value comprises an RF power peak value limit value and a mean value limit value; and
said FPO processor is configured to convert said gradient power signal into said gradient power parameter so that said gradient power parameter comprises a gradient power peak value and a mean value calculated from said gradient power signal, and wherein gradient power limit value comprises a gradient power peak value limit value and gradient power mean limit value.

### Claim 8

An apparatus for achieving scanning safety for a magnetic resonance (MR) conditionally safe implant, said apparatus comprising:
a power signal processing processor configured to convert an RF power signal, received from an RF power sensor in an MR scanner into an RF power parameter, and to convert a gradient power signal, received from a gradient power sensor in said MR scanner, into a gradient power parameter;
a digital control processor in communication with said power signal processing processor, said digital control processor being configured to receive the RF power parameter and gradient power parameter from said power signal processing processor and to detect whether said RF power parameter exceeds an RF power limit value and whether said gradient power parameter exceeds a gradient power limit value;
said digital control processor being configured, when said RF power parameter exceeds said RF power limit value, to emit an shutdown signal that discontinues operation of an RF power amplifier that produces RF power represented by said RF power signal; and
said digital control processor being configured, when said gradient power parameter exceeds said gradient power limit value, to emit a shutdown signal that discontinues operation of a gradient power amplifier that produces gradient fields having a gradient power represented by said gradient power signal.

### Claim 9 (depends on 8)

An apparatus as claimed in claim 8 wherein:
said power signal processing processor is configured to convert said RF power signal into said RF power parameter so that said RF power parameter comprises an RF power peak value and a mean value calculated from said RF power signal, and wherein said RF power limit value comprises an RF power peak value limit value and a mean value limit value; and
said power signal processing processor is configured to convert said gradient power signal into said gradient power parameter so that said gradient power parameter comprises a gradient power peak value and a mean value calculated from said gradient power signal, and wherein gradient power limit value comprises a gradient power peak value limit value and gradient power mean limit value.

### Claim 10 (depends on 8)

An apparatus as claimed in claim 8 wherein:
said power signal processing processor comprises an RF power signal processor and a gradient power signal processor;
said RF power signal processor being integrated in said RF power sensor in said MR scanner and being configured to convert said RF power signal into said RF power parameter; and
said gradient power signal processor being integrated in said gradient power sensor in said MR scanner, and being configured to convert said gradient power signal to said gradient power parameter.

### Claim 11 (depends on 8)

An apparatus as claimed in claim 8 comprising a memory in communication with said power signal processing processor and said digital control processor, in which said digital control processor and said power signal processing processor are configured to store said RF power signal, said gradient power signal, said RF power parameter, and said gradient power parameter.

### Claim 12 (depends on 8)

An apparatus as claimed in claim 8 wherein said digital control processor comprises a user interface configured to receive and present information relevant to operation of said digital control processor.

### Claim 13 (depends on 8)

An apparatus as claimed in claim 8 comprising a power supply monitoring and watchdog processor configured to monitor a power supply state of at least one of said digital control processor and said power signal processing processor, and to discontinue operation of said radio-frequency power amplifier and said gradient power amplifier when said power supply state does not comply with a predetermined requirement, and to monitor a survival state of said digital control processor and, when necessary, to reset said digital control processor, if software operating said digital control processor fails.

### Claim 14 (depends on 8)

An apparatus as claimed in claim 8 comprising a universal input/output interface allowing external communication to and from at least said digital control processor.

### Claim 15

A method for achieving scanning safety for a magnetic resonance (MR) conditionally safe implant, during an MR scan conducted by an MR scanner comprising a radio-frequency (RF) power amplifier and an RF sensor that generates an RF power signal representing RF power emitted by said RF power amplifier, and a gradient power amplifier and a gradient power sensor that emits a gradient power sensor signal representing gradient power emitted by said gradient amplifier, said method comprising:
with a fixed parameter option (FPO) processor, operating the MR scanner in an FPO mode in said scan in order to comply with requirements for safely scanning a subject having a conditionally safe implant therein;
providing said RF power signal and said gradient power signal to said FPO processor and, in said FPO processor, converting said RF power signal into an RF power parameter and converting said gradient power signal into a gradient power parameter;
in said FPO processor, determining when at least one of said RF power parameter exceeds an RF power limit value or said gradient power parameter exceeds a gradient power limit value;
when said FPO processor determines that said RF power parameter exceeds said RF power limit value, emitting a shutdown signal from the FBO processor that causes operation of RF power amplifier to be discontinued; and
when said FPO processor determines that said gradient power parameter exceeds said gradient power limit value, emitting a shutdown signal from said FPO processor that causes operation of said gradient power amplifier to be discontinued.

### Claim 16 (depends on 15)

A method as claimed in claim 15 comprising:
in said FPO processor, converting said RF power signal into said RF power parameter so that said RF power parameter comprises an RF power peak value and a mean value calculated from said RF power signal, and wherein said RF power limit value comprises an RF power peak value limit value and a mean value limit value; and
in said FPO processor, converting said gradient power signal into said gradient power parameter so that said gradient power parameter comprises a gradient power peak value and a mean value calculated said gradient power signal, and wherein gradient power limit value comprises a gradient power peak value limit value and gradient power mean limit value.