Method for excluding magnetic objects from magnetic resonance imaging facility
View Patent ↗A method to screen individuals specifically for paramagnetic or ferromagnetic objects they may be carrying or wearing, before they enter the high-field region of an MRI suite. The device used comprises either a screening portal or a compact, hand-held magnetic gradiometer and its electronics. The method places all of the sensor arrays in close proximity to all parts of a subject's body, for screening purposes.
1. A method for excluding objects from proximity to an MRI instrument, said method comprising:
providing an array of sensors adapted to detect a magnetic field of an object, said sensor array being provided as at least two sensor sub-arrays;
mounting a first said sensor sub-array on a movable horizontal member on a portal structure;
mounting a second said sensor sub-array on at least one vertical member on said portal structure;
passing said recumbent patient through said portal structure, beneath said horizontal member, to accomplish positioning of the entirety of said first sensor sub-array to scan all portions of said recumbent human subject;
processing signals from said first sensor sub-array to detect said object;
moving said horizontal member to clear a passageway through said portal structure for an upright human subject, said passageway being adjacent to said at least one vertical member;
passing said upright human subject through said passageway, adjacent to said at least one vertical member, to accomplish positioning of the entirety of said second sensor sub-array to scan all portions of said upright human subject; and
processing signals from said second sensor sub-array to detect said object.
2. A method for excluding objects from proximity to an MRI instrument, said method comprising:
providing an array of sensors adapted to detect a magnetic field of an object;
mounting said sensor array on a hand-held frame;
providing a source of an external magnetic field mounted to said hand-held frame;
orienting said sensor array relative to said hand-held frame to distinguish between said external magnetic field and an induced magnetic field of said object;
passing said hand-held frame over a human subject to thereby position the entirety of said sensor array to scan all portions of said human subject; and
processing signals from said sensor array to detect said object.
3. The method recited in claim 2 , further comprising:
providing an electromagnet mounted to said hand-held frame as said external magnetic field source; and
generating an electromagnetic external field with said electromagnet.
4. The method recited in claim 3 , further comprising:
providing an AC electromagnet mounted to said hand-held frame; and
generating said external magnetic field with said AC electromagnet.
5. The method recited in claim 3 , further comprising:
providing a DC electromagnet mounted to said hand-held frame; and
generating said external magnetic field with said DC electromagnet.
6. The method recited in claim 2 , further comprising:
providing a permanent magnet mounted to said hand-held frame as said external magnetic field source; and
generating an electromagnetic external field with said permanent magnet.