摘要:
In the magnetic resonance imaging device, the distance between the first and second coils is different in the circumferential direction and has a first region (A1) (θ=0, π) and a second region (A2) (θ=π/2) narrower than the first region (A1). In the first coil, wiring patterns (17a, 17b) on the side of a zero-plane (F0) passing through the center of the first coil and perpendicular to the axis direction (z-axis direction) meander in the circumferential direction such that the wiring patterns (17a, 17b) depart from the zero-plane (F0) in the first region (A1) and approach the zero-plane (F0) in the second region (A2). This provides a gradient magnetic field coil capable of configuring wiring patterns without using a loop coil that does not pass through the z-axis.
摘要:
In a gradient magnetic field coil device including: a plurality of main coils generating in an imaging region of a magnetic field resonance imaging device a magnetic field distribution in which an intensity linearly inclines; and a plurality of shield coils, arranged on an opposite side of the imaging region across the main coils, suppressing residual magnetic field generated by the main coils on the opposite side. The plurality of main coils and the plurality of shield coils are connected in series. The device further includes a plurality of current adjusting devices, connected to the shield coils in parallel, independently adjusting currents flowing through the shield coils, respectively, to enhance symmetry of the residual magnetic field. The gradient magnetic field coil device is provided which can suppress generation of eddy current magnetic field even if there is a relative position deviation between the main coils and shield coils.
摘要:
In the magnetic resonance imaging device, the distance between the first and second coils is different in the circumferential direction and has a first region (A1) (θ=0, π) and a second region (A2) (θ=π/2) narrower than the first region (A1). In the first coil, wiring patterns (17a, 17b) on the side of a zero-plane (F0) passing through the center of the first coil and perpendicular to the axis direction (z-axis direction) meander in the circumferential direction such that the wiring patterns (17a, 17b) depart from the zero-plane (F0) in the first region (A1) and approach the zero-plane (F0) in the second region (A2). This provides a gradient magnetic field coil capable of configuring wiring patterns without using a loop coil that does not pass through the z-axis.
摘要:
The gradient coil for a magnetic resonance imaging apparatus is adapted to encode information on a spatial position of a subject to be inspected into a nuclear magnetic resonance signal. The gradient coil includes a primary gradient coil and a shielded gradient coil. The primary gradient coil generates a gradient magnetic field in the imaging area. The shielded gradient coil is located on the side opposite to the imaging area relative to the primary gradient coil and cancels the gradient magnetic field generated by the primary magnetic field. The shielded gradient coil has a first area including a central axis perpendicularly extending through the central portion of the imaging area and a second area located on the side of the outer circumference of the first area. The second area is more inclined toward the imaging area than the first area.
摘要:
In a gradient magnetic field coil device including: a plurality of main coils generating in an imaging region of a magnetic field resonance imaging device a magnetic field distribution in which an intensity linearly inclines; and a plurality of shield coils, arranged on an opposite side of the imaging region across the main coils, suppressing residual magnetic field generated by the main coils on the opposite side. The plurality of main coils and the plurality of shield coils are connected in series. The device further includes a plurality of current adjusting devices, connected to the shield coils in parallel, independently adjusting currents flowing through the shield coils, respectively, to enhance symmetry of the residual magnetic field. The gradient magnetic field coil device is provided which can suppress generation of eddy current magnetic field even if there is a relative position deviation between the main coils and shield coils.
摘要:
The gradient coil for a magnetic resonance imaging apparatus is adapted to encode information on a spatial position of a subject to be inspected into a nuclear magnetic resonance signal. The gradient coil includes a primary gradient coil and a shielded gradient coil. The primary gradient coil generates a gradient magnetic field in the imaging area. The shielded gradient coil is located on the side opposite to the imaging area relative to the primary gradient coil and cancels the gradient magnetic field generated by the primary magnetic field. The shielded gradient coil has a first area including a central axis perpendicularly extending through the central portion of the imaging area and a second area located on the side of the outer circumference of the first area. The second area is more inclined toward the imaging area than the first area.
摘要:
When the gradient magnetic field 9 is generated, a low magnetic field region 22 and a high magnetic field region 21 are generated where a magnetic field crossing at least one of the first forward coil 11a, a second forward coil 11b, first revere coil 11e, and a second reverse coil 11d has different intensities between the low and high magnetic field regions and the intensity in the high magnetic region is higher than the intensity in the low magnetic field region. A line width Dlh of the coil line in the high magnetic field region 21 is narrower than the line width Dll of the coil line 24 in the low magnetic field region 22. There is provided a gradient magnetic field coil can suppress in a usable range heat generations due to eddy current and due to a pulse large current which steeply varies.
摘要:
When the gradient magnetic field 9 is generated, a low magnetic field region 22 and a high magnetic field region 21 are generated where a magnetic field crossing at least one of the first forward coil 11a, a second forward coil 11b, first revere coil 11e, and a second reverse coil 11d has different intensities between the low and high magnetic field regions and the intensity in the high magnetic region is higher than the intensity in the low magnetic field region. A line width Dlh of the coil line in the high magnetic field region 21 is narrower than the line width Dll of the coil line 24 in the low magnetic field region 22. There is provided a gradient magnetic field coil can suppress in a usable range heat generations due to eddy current and due to a pulse large current which steeply varies.
摘要:
A gradient coil device includes a major axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a major axis direction of the ellipse at a magnetic field space; and a minor axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a minor axis direction of the ellipse at the magnetic field space. A length of the minor axis field coil in the center axis direction is shorter than a length of the major axis gradient coil in the center axis direction. A maximum value of a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space is equal to or smaller than a maximum value of a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space.
摘要:
There is provided a gradient coil device which can suppress any generation of an error magnetic field and thus an eddy current, and which can improve the image quality of a cross-sectional image. An MRI device includes a first coil generating a linear magnetic field distribution at an imaging region of the MRI device, and a second coil which suppresses any leakage of a magnetic field from the first coil to a static-magnetic-field coil device that generates a uniform magnetic field distribution at the imaging region.