Standard Test Method for Measurement of Radio Frequency Induced Heating Near Passive Implants During Magnetic Resonance Imaging
|Publication Date:||10 November 2002|
|ICS Code (Implants for surgery, prosthetics and orthotics):||11.040.40|
This test method covers measurement of Radio Frequency (RF) induced heating near a passive medical implant and its surroundings during Magnetic Resonance Imaging (MRI).
This test method is one of those required to determine if the presence of a passive implant may cause injury to the person with the implant during an MRI procedure. Other safety issues that should be addressed include magnetically induced displacement force and torque.
The amount of RF-induced temperature rise for a given specific absorption rate (SAR) will depend on the RF frequency, which is proportional to the static magnetic field strength. Because of possible additional heating, particularly when device dimensions exceed a quarter wavelength, conclusions from measurements made at one frequency may not apply to other frequencies. While the focus in this test method is on 1.5 T cylindrical bore imagers, the RF-induced temperature rise in the open MRI systems can be evaluated by suitable modification of the methods described here.
This test method assumes that testing is done on devices that will be entirely inside the body.
This test method applies to whole body magnetic resonance equipment, as defined in section 2.2.103 of the IEC Standard 60601-2-33, Ed. 2.0, with a whole body RF transmit coil as defined in section 2.2.100. The RF coil is assumed to have quadrature excitation.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.