Magnetic resonance method and apparatus for reducing RF heating in the patient
First Claim
1. A magnetic resonance imaging system comprising:
- a magnetic resonance data acquisition unit comprising a basic field magnet with an opening therein adapted to receive an examination subject therein, said examination subject carrying, extracorporeally or intracorporeally, a foreign object at least partially formed of electrically conductive material;
said magnetic resonance data acquisition unit comprising a gradient coil system and a radio-frequency (RF) coil system that at least partially surround the examination subject in said opening, said RF coil system having a coil design;
an RF transmit system connected to said RF coil system that supplies current to said RF coil system to radiate an RF field in the examination subject disposed in said opening, said RF field contributing to production of an electric field in the examination subject that causes RF heating of the examination subject;
a gradient coil control system connected to said gradient coil system that supplies current to said gradient coil system to produce gradient magnetic fields in said examination subject;
a sequence controller connected to said RF transmit system and said gradient coil control system, said sequence controller being configured to operate said RF transmit system and said gradient coil control system to activate and deactivate said RF field and said gradient magnetic fields in a sequence to produce, spatially encode, and read out magnetic resonance signals in said examination subject;
an input unit in communication with said sequence controller configured to provide said sequence controller with information describing electrically conductive characteristics of said foreign object; and
said sequence controller being configured to use said information to set said sequence, in combination with said design of said RF coil, to steer or modify said electric field to minimize RF heating in the examination subject due to the presence of said foreign object.
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Accused Products
Abstract
In a magnetic resonance data acquisition method and system for acquiring data from a patient who carries, either intracorporeally or extracorporeally, a foreign object at least partially composed of electrically conductive material, RF heating to the patient due to the presence of the foreign object is minimized by radiating the patient with RF energy by an RF coil that has a coil design. The sequence of pulses to which the patient is subjected to acquire magnetic resonance data from the patient is configured, in combination with the coil design of the RF coil to steer or modify the electric field that arises in the patient so that RF heating in the patient due to the presence of the foreign object is minimized.
24 Citations
15 Claims
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1. A magnetic resonance imaging system comprising:
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a magnetic resonance data acquisition unit comprising a basic field magnet with an opening therein adapted to receive an examination subject therein, said examination subject carrying, extracorporeally or intracorporeally, a foreign object at least partially formed of electrically conductive material; said magnetic resonance data acquisition unit comprising a gradient coil system and a radio-frequency (RF) coil system that at least partially surround the examination subject in said opening, said RF coil system having a coil design; an RF transmit system connected to said RF coil system that supplies current to said RF coil system to radiate an RF field in the examination subject disposed in said opening, said RF field contributing to production of an electric field in the examination subject that causes RF heating of the examination subject; a gradient coil control system connected to said gradient coil system that supplies current to said gradient coil system to produce gradient magnetic fields in said examination subject; a sequence controller connected to said RF transmit system and said gradient coil control system, said sequence controller being configured to operate said RF transmit system and said gradient coil control system to activate and deactivate said RF field and said gradient magnetic fields in a sequence to produce, spatially encode, and read out magnetic resonance signals in said examination subject; an input unit in communication with said sequence controller configured to provide said sequence controller with information describing electrically conductive characteristics of said foreign object; and said sequence controller being configured to use said information to set said sequence, in combination with said design of said RF coil, to steer or modify said electric field to minimize RF heating in the examination subject due to the presence of said foreign object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for operating a magnetic resonance imaging system comprising the steps of:
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placing an examination subject in an opening of a magnetic resonance data acquisition unit, said examination subject carrying, extracorporeally or intracorporeally, a foreign object at least partially formed of electrically conductive material; supplying current to an RF coil system substantially surrounding said opening in said data acquisition unit, said RF coil system being configured to exhibit a substantially linear sensitivity profile at least in a portion of said opening occupied by said examination subject, to radiate an RF field in the examination subject disposed in said opening, said RF field contributing to production of an electric field in the examination subject that causes RF heating of the examination subject; also supplying current to a gradient coil system of the data acquisition unit to produce gradient magnetic fields in said examination subject; with a sequence controller, activating and deactivating said RF field and said gradient magnetic fields in a sequence to produce, spatially encode, and read out magnetic resonance signals in said examination subject; providing said sequence controller with information describing electrically conductive characteristics of said foreign object; and in said sequence controller using said information to set said sequence, in combination with said linear sensitivity of said RF coil, to steer said electric field to minimize RF heating in the examination subject due to the presence of said foreign object. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. An implant-compatible electrical device comprising:
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a source of a radio-frequency (RF) field; a device that causes said RF field to interact with a living subject carrying, extracorporeally or intracorporeally, a foreign object that is at least partially formed of electrically conductive material; and a control device supplied with information describing electrically conductive characteristics of said foreign object, said control device being configured to steer or modify said electrical field, dependent on said information, to minimize RF heating in said subject due to the presence of the foreign object.
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15. A method for reducing RF heating in a living subject comprising the steps of:
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in an electrical device, generating a radio-frequency (RF) field; placing said device relative to a living subject carrying, extracorporeally or intracorporeally, a foreign object that is at least partially formed of electrically conductive material, to cause said electrical field to interact with said living subject; and supplying a control device with information describing electrically conductive characteristics of said foreign object, and from said control device, steering or modifying said electrical field, dependent on said information, to minimize RF heating in said subject due to the presence of the foreign object.
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Specification