US4788834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system for controlling magnetic field generating unit in magnetic resonance imaging apparatus
Assignee: Toshiba Corp
•
Filing: 1987-11-10
•
Granted: 1988-12-06
•
Expires: 2007-11-10
Abstract
Abstract To reduce the running cost of an MRI apparatus, power supplied to a normal conductive coil from a pre-regulator is reduced in an idling mode. This reduction in power also reduces the heat generated in the normal conductive coil and a shunt resistor. A computer controls a cooling unit according to the amount of the heat reduced in order to reduce to flow rate of a cooling medium. In this manner, the temperatures of the normal conductive coil and shunt resistor can be maintained at constant levels. Further, if a current value is set to maintain the temperatures of the normal conductive coil and shunt resistor at the constant levels only by natural heat radiating, circulation of the cooling medium can be stopped.
Inventors
- 👤 Yoshiyuki Usui
- 👤 Koji Kitamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:42
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/3804
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
161 words
A method for controlling a magnetic field generating unit in a magnetic resonance imaging apparatus comprising the steps of: inputting selectively a signal to specify one of a scanning mode and an idling mode in the magnetic resonance imaging apparatus; supplying a power to a normal conductive coil for generating a static magnetic field in the scanning mode; detecting temperatures of a shunt resistor and the normal conductive coil that are heated by the supplied power; controlling the temperatures of the normal conductive coil and the shunt resistor by operating a flow rate of a cooling medium in accordance with the detected temperatures; reducing the power supplied to the normal conductive coil in the idling mode; detecting temperatures of the normal conductive coil and the shunt resistor due to reduction in the power; and controlling the temperatures of the normal conductive coil and the shunt resistor by operating the flow rate of the cooling medium in accordance with the detected temperatures.
Claim 2
Independent Claim
161 words
A method for controlling a magnetic field generating unit in a magnetic resonance imaging apparatus comprising the steps of: inputting selectively a signal to specify one of a scanning mode and an idling mode in the magnetic resonance imaging apparatus; supplying a power to a normal conductive coil for generating a static magnetic field in the scanning mode; detecting temperatures of a shunt resistor and the normal conductive coil that are heated by the supplied power; controlling the temperatures of the normal conductive coil and the shunt resistor by operating a flow rate of a cooling medium in accordance with the detected temperatures; reducing the power supplied to the normal conductive coil in the idling mode; detecting temperatures of the normal conductive coil and the shunt resistor due to reduction in the power; and controlling the temperatures of the normal conductive coil and the shunt resistor by operating the flow rate of the cooling medium in accordance with the detected temperatures.
Claim 3
Dependent Claim
37 words
The method according to claim 1, wherein a value for current flowing through the normal conductive coil in the scanning mode is set to a current value necessary to generate a magnetic field with a predetermined intensity.
Claim 4
Dependent Claim
45 words
The method according to claim 1, wherein a value for current flowing through the normal conductive coil in the idling mode is set to such a value as an amount of heat generated from the normal conductive coil equals an amount of heat naturally radiated.
Claim 5
Dependent Claim
33 words
The method according to claim 1, wherein temperatures of the normal conductive coil and the shunt resistor are detected by measuring a temperature of the cooling medium using a plurality of temperature sensors.
Claim 6
Dependent Claim
28 words
The method according to claim 1, wherein the flow rate of the cooling medium is controlled by driving at least one pump and at least one electromagnetic valve.
Claim 7
Dependent Claim
23 words
The method according to claim 1, wherein the flow rate of the cooling medium is controlled by driving only at least one pump.
Claim 8
Independent Claim
172 words
A system for controlling a magnetic field generating unit in a magnetic resonance imaging apparatus, comprising: means for inputting selectively a signal to specify one of a scanning mode and an idling mode in the magnetic resonance imaging apparatus; means for supplying a power to a normal conductive coil for generating a static magnetic field in the scanning mode; means for detecting temperatures of a shunt resistor and the normal conductive coil that are heated by the supplied power; means for controlling the temperatures of the normal conductive coil and the shunt resistor by operating a flow rate of a cooling medium in accordance with the detected temperatures; means for reducing the power supplied to the normal conductive coil in the idling mode; means for detecting temperatures of the normal conductive coil and the shunt resistor due to reduction in the power; and means for controlling the temperatures of the normal conductive coil and the shunt resistor by operating the flow rate of the cooling medium in accordance with the detected temperatures.
Claim 9
Independent Claim
172 words
A system for controlling a magnetic field generating unit in a magnetic resonance imaging apparatus, comprising: means for inputting selectively a signal to specify one of a scanning mode and an idling mode in the magnetic resonance imaging apparatus; means for supplying a power to a normal conductive coil for generating a static magnetic field in the scanning mode; means for detecting temperatures of a shunt resistor and the normal conductive coil that are heated by the supplied power; means for controlling the temperatures of the normal conductive coil and the shunt resistor by operating a flow rate of a cooling medium in accordance with the detected temperatures; means for reducing the power supplied to the normal conductive coil in the idling mode; means for detecting temperatures of the normal conductive coil and the shunt resistor due to reduction in the power; and means for controlling the temperatures of the normal conductive coil and the shunt resistor by operating the flow rate of the cooling medium in accordance with the detected temperatures.
Claim 10
Dependent Claim
40 words
The system according to claim 7, wherein a value for current flowing through the normal conductive coil in the scanning mode is obtained by means for setting a current value necessary to generate a magnetic field with a predetermined intensity.
Claim 11
Dependent Claim
49 words
The system according to claim 7, wherein a value for current flowing through the normal conductive coil in the idling mode is obtained by means for setting such a value as an amount of heat generated from the normal conductive coil equal to an amount of heat naturally radiated.
Claim 12
Dependent Claim
35 words
The system according to claim 7, wherein temperatures of the normal conductive coil and the shunt resistor are detected by means for measuring a temperature of the cooling medium using a plurality of temperature sensors.
Claim 13
Dependent Claim
30 words
The system according to claim 7, wherein the flow rate of the cooling medium is controlled by means for driving at least one pump and at least one electromagnetic valve.
Claim 14
Dependent Claim
25 words
The system according to claim 7, wherein the flow rate of the cooling medium is controlled by means for driving only at least one pump.
References Cited (Backward Citations)
US3022641A
Cited
US3434299A
Cited
US3803864A
Cited
US4590428A
Cited
US4652824A
Cited
US4658593A
Cited
US4595899A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |