Rotating frame imaging system
OwnerAlbert Macovskiinventor
Life of this patent
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Abstract
Following the polarizing of the magnetic moments in an object using a pulsed field the moment distribution is imaged in the rotating frame by exciting the magnetic moments using a radio-frequency gradient field and a radio-frequency bias field whose phase is cyclically oscillated to prevent the loss of signal due to inhomogeniety. To increase the signal-to-noise ratio coils are used to pick up the signals at quadrature positions. A constant gradient is used for spatial selectivity through saturation.
Claims26
In a method for imaging the magnetic moment density in an object the steps of:
- polarizing the magnetic moments with a pulsed magnetic field;
- spatially selectively rotating the magnetic moments using radio frequency gradient fields pointing normal to the pulsed magnetic field;
- receiving signals from the rotating magnetic moments;
- and
- processing the received signals to form an image of the object.
In a method for imaging the magnetic moment density in an object the steps of:
- polarizing the magnetic moments with a first magnetic field;
- spatially selectively rotating the magnetic moments using radio frequency gradient fields pointing normal to the first magnetic field;
- applying a radio frequency bias field in the same direction as the gradient field and including the step of cyclically reversing the phase of the bias field to provide immunity to inhomogeniety;
- receiving signals from the rotating magnetic moments;
- and
- processing the received signals to form an image of the object.
Apparatus for imaging the magnetic moment density in an object comprising:
- means for polarizing the magnetic moments with a pulsed magnetic field;
- means for spatially selectively rotating the magnetic moments using radio frequency gradient fields pointing normal to the pulsed magnetic field;
- means for receiving signals from the rotating magnetic moments;
- and
- means for processing the received signals to form an image of the object.
Apparatus for imaging the magnetic moment density in an object comprising:
- means for polarizing the magnetic moments with a first magnetic field;
- means for spatially selectively rotating the magnetic moments using radio frequency gradient fields pointing normal to the first magnetic field;
- means for applying a radio frequency bias field in the same direction as the gradient field and means for cyclically reversing the phase of the bias field to provide immunity to inhomogeniety;
- means for receiving signals from the rotating magnetic moments;
- and
- means for processing the received signals to form an image of the object.
Apparatus for imaging the magnetic moment density in an object comprising:
- means for polarizing the magnetic moments with a pulsed magnetic field;
- means for spatially selectively rotating the magnetic moments using radio frequency gradient fields pointing normal to the first magnetic field;
- means for receiving signals from the rotating magnetic moments using two receiving coils in substantial spatial quadrature relationship to each other;
- and
- means for processing the received signals to form an image of the object.
Dependencies are inferred from the claim text.