ASTM F2182-19e2
(Test Method)Standard Test Method for Measurement of Radio Frequency Induced Heating On or Near Passive Implants During Magnetic Resonance Imaging
Standard Test Method for Measurement of Radio Frequency Induced Heating On or Near Passive Implants During Magnetic Resonance Imaging
SIGNIFICANCE AND USE
5.1 This test method describes a test procedure for evaluating the ∆T associated with RF power deposition during an MR procedure, involving a specific frequency of RF irradiation of a passive implant. The method allows characterization of the heating propensity of an implant rather than the prediction of heating during a specific MR procedure in a patient. The results may be used as an input to a computational model for estimating ∆T due to the presence of that implant in a patient. The combination of the test results and the computational model results may then be used to help assess the safety of a patient with the implant during an MR examination.
SCOPE
1.1 This test method covers measurement of radio frequency (RF)-induced heating on or near a passive medical implant within a phantom during magnetic resonance imaging (MRI). The test method does not specify levels of heating considered to be safe to the patient and relies on users to define their own acceptance criteria.
1.2 This test method does not address other possible safety issues which include, but are not limited to: issues of magnetically-induced displacement, magnetically-induced torque, image artifact, acoustic noise, tissue heating, interaction among devices, and the functionality of the device and the MR system.
1.3 The amount of RF-induced temperature rise (∆T) for a given incident electric field will depend on the RF frequency, which is dependent on the static magnetic field strength of the MR system. While the focus in this test method is on 1.5 tesla (T) or 3 T MR systems, the ∆T for an implant in MR systems of other static magnetic field strengths or magnet designs can be evaluated by suitable modification of the method described herein.
1.4 This test method assumes that testing is done on devices that will be entirely inside the body. Testing for devices with other implantation conditions (e.g., external fixation devices, percutaneous needles, catheters or tethered devices such as ablation probes) is beyond the scope of this standard; for such devices, modifications of this test method may be necessary.
Note 1: RF-heating induced by any electrically conductive implanted device may be impacted by the presence of other metallic or otherwise electrically conductive devices present nearby.
1.5 This test method is written for several possible RF exposure systems, including Volume RF transmit coils. The exposure system needs to be properly characterized, within the stated uncertainties, in term of local background RF exposure for the implants which are tested.
1.6 The values stated in SI units are to be regarded as standard.
1.7 A device with deployed dimensions of less than 2 cm in all directions may not need to be tested with respect to RF-induced heating, as it is expected to generate ∆T of less than 2°C over 1 h of exposure at 1.5 T/64-MHz or 3 T/128-MHz frequencies (1, 2)2 and ANSI/AAMI/ISO 14708-3:2017). This condition is not valid when multiple replicas of the device (e.g., multiple anchors) are implanted within 3 cm of the device.
Note 2: The above values were derived from existing data and literature. The 3 cm distance is recommended to avoid any RF coupling with other neighboring devices.
1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: F2182 − 19
Standard Test Method for
Measurement of Radio Frequency Induced Heating On or
Near Passive Implants During Magnetic Resonance
1
Imaging
This standard is issued under the fixed designation F2182; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Editorially revised throughout in January 2020.
2
ε NOTE—Corrected editorially in April 2020.
1. Scope 1.5 This test method is written for several possible RF
exposure systems, including Volume RF transmit coils. The
1.1 This test method covers measurement of radio fre-
exposuresystemneedstobeproperlycharacterized,withinthe
quency (RF)-induced heating on or near a passive medical
stated uncertainties, in term of local background RF exposure
implant within a phantom during magnetic resonance imaging
for the implants which are tested.
(MRI). The test method does not specify levels of heating
consideredtobesafetothepatientandreliesonuserstodefine
1.6 The values stated in SI units are to be regarded as
their own acceptance criteria.
standard.
1.2 This test method does not address other possible safety
1.7 Adevice with deployed dimensions of less than 2 cm in
issues which include, but are not limited to: issues of
all directions may not need to be tested with respect to
magnetically-induced displacement, magnetically-induced
RF-induced heating, as it is expected to generate �T of less
torque, image artifact, acoustic noise, tissue heating, interac-
than 2°C over1hof exposure at 1.5 T/64-MHz or 3
tionamongdevices,andthefunctionalityofthedeviceandthe
2
T/128-MHz frequencies (1, 2) and ANSI/AAMI/ISO 14708-
MR system.
3:2017). This condition is not valid when multiple replicas of
1.3 The amount of RF-induced temperature rise (�T) for a
thedevice(e.g.,multipleanchors)areimplantedwithin3cmof
given incident electric field will depend on the RF frequency,
the device.
which is dependent on the static magnetic field strength of the
MR system. While the focus in this test method is on 1.5 tesla NOTE 2—The above values were derived from existing data and
literature. The 3 cm distance is recommended to avoid any RF coupling
(T) or 3 T MR systems, the �T for an implant in MR systems
with other neighboring devices.
of other static magnetic field strengths or magnet designs can
be evaluated by suitable modification of the method described
1.8 This standard does not purport to address all of the
herein.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.4 Thistestmethodassumesthattestingisdoneondevices
priate safety, health, and environmental practices and deter-
that will be entirely inside the body. Testing for devices with
mine the applicability of regulatory limitations prior to use.
other implantation conditions (e.g., external fixation devices,
percutaneous needles, catheters or tethered devices such as
1.9 This international standard was developed in accor-
ablation probes) is beyond the scope of this standard; for such dance with internationally recognized principles on standard-
devices, modifications of this test method may be necessary.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
NOTE 1—RF-heating induced by any electrically conductive implanted
mendations issued by the World Trade Organization Technical
device may be impacted by the presence of other metallic or otherwise
electrically conductive devices present nearby. Barriers to Trade (TBT) Committee.
1
ThistestmethodisunderthejurisdictionofASTMCommitteeF04onMedical
andSurgicalMaterialsandDevicesandisthedirectresponsibilityofSubcommittee
F04.15 on Material Test Methods.
Current edition approved Sept. 15, 2019. Published October 2019. Originally
2
approved in 2002. Last previous edition approved in 2011 as F2182–11a. DOI: The boldface numbers in parentheses refer to a list of references at the end of
10.1520/F2182-19E02. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2182 − 19
2. Referenced Documents The local background SAR can be derived from the tem-
3 perature with the following equation:
2.1 ASTM Standards:
B348Specification for Titanium and Titanium Alloy Bars ∆T
SAR 5lim c (1)
and Billets ∆t
t→0
F2052Test Method for Measurement of Magnetically
...
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