US 12,007,456 B2
Limiting RF alternating magnetic field in MRI
Ying Lun Wang, Shenzhen (CN); Qiu Yi Zhang, Shenzhen (CN); and Zhi Bin Li, Shenzhen (CN)
Assigned to Siemens Healthineers AG, Erlangen (DE)
Filed by Siemens Healthcare GmbH, Erlangen (DE)
Filed on Dec. 12, 2022, as Appl. No. 18/079,525.
Claims priority of application No. 202111517254.7 (CN), filed on Dec. 13, 2021.
Prior Publication US 2023/0184857 A1, Jun. 15, 2023
Int. Cl. G01R 33/32 (2006.01); G01R 33/422 (2006.01)
CPC G01R 33/422 (2013.01) [G01R 33/32 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for limiting an RF (radio frequency) alternating magnetic field in MRI (magnetic resonance imaging), the method comprising:
measuring a perpendicular distance between a local coil placed on a scanned part of a patient and a center of a detection hole of an MR scanner;
based on the perpendicular distance between the local coil and the center of the detection hole, determining a deviation between a field strength of the RF alternating magnetic field at a position of the local coil during an MR scan and a field strength of the RF alternating magnetic field at the center of the detection hole;
based on the deviation, computing a conversion coefficient for conversion between the field strength of the RF alternating magnetic field at the position of the local coil and the field strength of the RF alternating magnetic field at the center of the detection hole; and
based on a field strength of the RF alternating magnetic field required when a surface temperature of the local coil is equal to a safe temperature upper limit and the conversion coefficient, computing a maximum permissible field strength of the RF alternating magnetic field at the center of the detection hole.