ASTM F2052-06e1
(Test Method)Standard Test Method for Measurement of Magnetically Induced Displacement Force on Medical Devices in the Magnetic Resonance Environment
Standard Test Method for Measurement of Magnetically Induced Displacement Force on Medical Devices in the Magnetic Resonance Environment
SIGNIFICANCE AND USE
This test method is one of those required to determine if the presence of a medical device may cause injury to individuals during an MR examination and in the MR environment. Other safety issues which should be addressed include but may not be limited to magnetically induced torque (see Test Method F 2213) and RF heating (see Test Method F 2182). The terms and icons in Practice F 2503 should be used to mark the device for safety in the magnetic resonance environment.
If the device deflects less than 45°, then the magnetically induced deflection force is less than the force on the device due to gravity (its weight). For this condition, it is assumed that any risk imposed by the application of the magnetically induced force is no greater than any risk imposed by normal daily activity in the Earth’gravitational field.
A deflection of less than 45° at the location of the maximum static magnetic field gradient in one MR system does not preclude a deflection exceeding 45° in a system with a higher field strength or larger static field gradients.
This test method alone is not sufficient for determining if a device is safe in the MR environment.
SCOPE
1.1 This test method covers the measurement of the magnetically induced displacement force produced by static magnetic field gradients on medical devices and the comparison of that force to the weight of the medical device.
1.2 This test method does not address other possible safety issues which include but are not limited to issues of magnetically induced torque, RF heating, induced heating, acoustic noise, interaction among devices, and the functionality of the device and the MR system.
1.3 This test method is intended for devices that can be suspended from a string. Devices which cannot be suspended from a string are not covered by this test method. The weight of the string from which the device is suspended during the test must be less than 1 % of the weight of the tested device.
1.4 This test method shall be carried out in a system in which the direction of the magnetically induced deflection force is horizontal.
1.5 The values stated in SI units are to be regarded as standard. Values in parentheses are for information only.
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 requirements prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: F2052 − 06
StandardTest Method for
Measurement of Magnetically Induced Displacement Force
on Medical Devices in the Magnetic Resonance
Environment
This standard is issued under the fixed designation F2052; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Paragraph X1.3 was added editorially in May 2006.
1. Scope F2119 Test Method for Evaluation of MR Image Artifacts
from Passive Implants
1.1 This test method covers the measurement of the mag-
F2182 Test Method for Measurement of Radio Frequency
netically induced displacement force produced by static mag-
Induced Heating On or Near Passive Implants During
netic field gradients on medical devices and the comparison of
Magnetic Resonance Imaging
that force to the weight of the medical device.
F2213 Test Method for Measurement of Magnetically In-
1.2 This test method does not address other possible safety
duced Torque on Medical Devices in the Magnetic Reso-
issues which include but are not limited to issues of magneti-
nance Environment
cally induced torque, RF heating, induced heating, acoustic
F2503 Practice for Marking Medical Devices and Other
noise, interaction among devices, and the functionality of the
Items for Safety in the Magnetic Resonance Environment
device and the MR system.
2.2 Other Standards:
1.3 This test method is intended for devices that can be
IEC 60601–2–33 Ed. 2.0 Medical Electronic Equipment—
suspended from a string. Devices which cannot be suspended
Part2:ParticularRequirementsfortheSafetyofMagnetic
from a string are not covered by this test method. The weight
Resonance Equipment for Medical Diagnosis
ofthestringfromwhichthedeviceissuspendedduringthetest
ISO 13485:2003(E) Medical Devices—Quality Manage-
must be less than 1 % of the weight of the tested device.
ment Systems—Requirements for Regulatory Purposes,
definition 3.7
1.4 This test method shall be carried out in a system in
which the direction of the magnetically induced deflection
force is horizontal. 3. Terminology
1.5 The values stated in SI units are to be regarded as 3.1 Definitions:
standard. Values in parentheses are for information only. 3.1.1 diamagnetic material—a material whose relative per-
meability is less than unity.
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.1.2 ferromagnetic material—a material whose magnetic
responsibility of the user of this standard to establish appro-
moments are ordered and parallel producing magnetization in
priate safety and health practices and determine the applica- one direction.
bility of regulatory requirements prior to use.
3.1.3 magnetic field strength (H in A/m)—strength of the
applied magnetic field.
2. Referenced Documents
3.1.4 magnetic induction or magnetic flux density (B in
2.1 ASTM Standards:
T)—that magnetic vector quantity which at any point in a
magnetic field is measured either by the mechanical force
experiencedbyanelementofelectriccurrentatthepoint,orby
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
the electromotive force induced in an elementary loop during
F04.15 on Material Test Methods.
any change in flux linkages with the loop at the point. The
Current edition approved April 28, 2006. Published March 2006. Originally
magnetic induction is frequently referred to as the magnetic
approved in 2000. Last previous edition approved in 2002 as F2052 – 02. DOI:
10.1520/F2052-06E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F2052 − 06
field. B isthestaticfieldinanMRsystem.Plaintypeindicates 3.1.13 paramagnetic material—a material having a relative
o
a scalar (for example, B) and bold type indicates a vector (for permeability which is slightly greater than unity, and which is
practically independent of the magnetizing force.
example,B).
3.1.14 tesla, (T)—the SI unit of magnetic induction equal to
3.1.5 magnetic resonance diagnostic device—a device in-
10 gauss (G).
tended for general diagnostic use to present images which
reflectthespatialdistributionormagneticresonancespectra,or
4. Summary of Test Method
both, which reflect frequency and distribution of nuclei exhib-
4.1 Amedical device is suspended by a string at the point in
iting nuclear magnetic resonance. Other physical parameters
a magnetic field that will produce the greatest magnetically
derived from the images or spectra, or both, may also be
induced deflection. The angular deflection of the string from
produced.
the vertical is measured. If the device deflects less than 45°,
3.1.6 magnetic resonance (MR) environment—volume
then the magnetically induced deflection force is less than the
within the 0.50 mT (5 gauss (G)) line of an MR system, which
force on the device due to gravity (its weight).
includes the entire three dimensional volume of space sur-
rounding the MR scanner. For cases where the 0.50 mT line is 5. Significance and Use
contained within the Faraday shielded volume, the entire room
5.1 This test method is one of those required to determine if
shall be considered the MR environment.
the presence of a medical device may cause injury to individu-
als during an MR examination and in the MR environment.
3.1.7 magnetic resonance equipment (MR equipment)—
Other safety issues which should be addressed include but may
medical electrical equipment which is intended for in-vivo
notbelimitedtomagneticallyinducedtorque(seeTestMethod
magnetic resonance examination of a patient. The MR equip-
F2213) and RF heating (see Test Method F2182). The terms
ment comprises all parts in hardware and software from the
and icons in Practice F2503 should be used to mark the device
supply mains to the display monitor. The MR equipment is a
for safety in the magnetic resonance environment.
Programmable Electrical Medical System (PEMS).
5.2 If the device deflects less than 45°, then the magneti-
3.1.8 magnetic resonance system (MR system)— ensemble
cally induced deflection force is less than the force on the
of MR equipment, accessories, including means for display,
device due to gravity (its weight). For this condition, it is
control, energy supplies, and the MR environment.
assumed that any risk imposed by the application of the
IEC 60601–2–33
magnetically induced force is no greater than any risk imposed
3.1.9 magnetic resonance examination (MR examination)—
by normal daily activity in the Earth’s gravitational field.
process of acquiring data by magnetic resonance from a
5.3 A deflection of less than 45° at the location of the
patient.
maximum static magnetic field gradient in one MR system
does not preclude a deflection exceeding 45° in a system with
3.1.10 magnetic resonance (MR)—resonant absorption of
a higher field strength or larger static field gradients.
electromagnetic energy by an ensemble of atomic particles
situated in a magnetic field.
5.4 This test method alone is not sufficient for determining
if a device is safe in the MR environment.
3.1.11 medical device—any instrument, apparatus,
implement, machine, appliance, implant, in vitro reagent or
6. Apparatus
calibrator, software, material, or other similar or related article,
6.1 The test fixture consists of a sturdy nonmagnetic struc-
intended by the manufacturer to be used, alone or in
ture capable of holding the test device in the proper position
combination, for human beings for one or more of the specific
withoutdeflectionofthetestfixtureandcontainingaprotractor
purpose(s) of:
with 1° graduated markings, rigidly mounted to the structure.
(1) diagnosis, prevention, monitoring, treatment, or allevia-
The 0° indicator on the protractor is oriented vertically. The
tion of disease,
(2) diagnosis, monitoring, treatment, alleviation of, or com-
testdeviceissuspendedfromathinstringthatisattachedtothe
pensation for an injury,
0° indicator on the protractor. In order for the weight of the
(3) investigation, replacement, modification, or support of the
stringtobeconsiderednegligiblewhencomparedtotheweight
anatomy or of a physiological process,
(4) supporting or sustaining life,
of the device, the weight of the string shall be less than 1 % of
(5) control of conception,
the weight of the device. The string shall be long enough so
(6) disinfection of medical devices, and
thatthedevicemaybesuspendedfromthetestfixtureandhang
(7) providing information for medical purposes by means of
in vitro examination of specimens derived from the hu-
freelyinspace.Motionofthestringshallnotbeconstrainedby
man body, and which does not achieve its primary in-
the support structure or the protractor. The string may be
tended action in or on the human body by
pharmacological, immunological, or metabolic means, attached to the device at any convenient location.
but which may be assisted in its function by such means.
ISO 13485
7. Test Specimens
3.1.12 magnetically induced displacement force— force
7.1 For purposes of device qualification, the device evalu-
produced when a magnetic object is exposed to the spatial ated according to this test method should be representative of
gradient of a magnetic field. This force will tend to cause the
manufactured medical devices that have been processed to a
object to translate in the gradient field. finished condition (for example, sterilized).
´1
F2052 − 06
7.2 For purposes of device qualification, the devices should
not be altered in any manner prior to testing.
8. Procedure
8.1 Any magnet with a horizontal magnetic field that
produces a large spatial gradient may be used for the test. Fig.
1 shows the test fixture mounted on the patient table of an MRI
system. The test device is suspended from a string attached to
the 0° indicator on the test fixture protractor. Position the test
fixture so that the center of mass of the device is at the location
where the deflection is a maximum (see Note 1). Mark the
location of the maximum deflection so all test repetitions will
be conducted at the same location. Hold the device so that the
string is vertical and then release it. Recordα, the deflection of
the device from the vertical direction to the nearest 1° (see Fig.
FIG. 2 Test Device in Magnetic Field
2).
8.2 Repeat the process in 8.1 a minimum of three times for
each device tested.
9. Calculations
8.3 The device should be constrained so that the bulk of the
9.1 Calculate the mean deflection angle using the absolute
device is at the point of maximum deflection (see Appendix
values of the values for deflection angle, α, measured in
X2). If anything (for example, tape) is used to constrain the
Section 8. (It is possible that instead of being attracted to the
device during the test, demonstrate that the added mass does
magnet,thedevicemightberepelledbythemagnet.Therefore,
not significantly affect the measurement.The combined weight
the absolute value of the deflection angle should be used when
of material used to constrain the device during the test shall be
calculating the mean deflection angle.)
less than 1 % of the weight of the device.
9.2 Calculate the mean magnetically induced deflection
8.4 If the device contains an electrical cord or some type of
force for the device using the mean value for the deflection
tether, arrange the device so the cord or tether has a minimal
angle α determined in 9.1 and the following relation (derived
effect on the measurement. For such devices, it may be
in Appendix X2): F = mg tanα, where m is the mass of the
m
necessary to perform a series of tests to characterize the
device and g is the acceleration due to gravity. If the mean
operating conditions that will produce the maximum deflec-
value for α is less than 45°, F , the magnetically induced
m
tion. (For instance, for an electrically powered device, tests in
deflection force, is less than the force on the device due to
anumberofstatesmaybenecessarytodeterminetheoperating
gravity (its weight).
condition that produces the maximum deflection. Possible test
configurations include but are not limited to: electrical cord
10. Report
only, device only, device with cord attached and device turned
10.1 The report shall include the following for each speci-
off, device with cord attached and device activated).
men tested:
NOTE 1—For devices below saturation, the location of maximum
10.1.1 Device product description, including dimensioned
deflection is at the point where |B||π B| is a maximum. Above the
magnetic saturation point, the maximum deflection will occur at the drawing(s) or photograph(s) with dimensional scale.
location where πB is a maximum.
10.1.2 A diagram or photograph showing the configuration
of the device during the test.
10.1.3 Device product identification (for example, batch, lot
number, type number, revision, serial number, date of manu-
facture).
10.1.4 Materials of construction (ASTM designation or
other).
10.1.5 Number of specimens tested with explanation for the
sample size used.
10.1.6 Cartesian coordinate (x, y, z) location of the center of
mass of the device during the test using a right handed
coordinate system with origin at the isocenter of the magnet.
Includeadiagramshowingthemagnetandthecoordinateaxes.
If the test magnet is an MR system, orient the coordinate
system so that the y-axis is vertical and the z-axis is parallel to
the patient table.
NOTE 1—The fixture may need to be offset to locate the position of
10.1.7 Valuesof|B|,themagnitudeofthemagneticfieldand
maximum deflection.
|πB|, the magnitude of the spatial gradient of the magnetic
FIG. 1 Test Fixture Mounted on the Patient Table of an MRI Sys-
tem field, at the test location.
´1
F2052 − 06
10.1.8 Measured deflection angle, α, at the test location for 11. Precision and Bias
each repetition of the test.
11.1 The precision and bias of this test method has not been
10.1.9 Mean deflection angle calculated using the absolute
established.
value of the measured values for deflection angle, α.
10.1.10 Weight of the tested device.
12. Keywords
10.1.11 Weightofthestringusedtosuspendthedevicefrom
t
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.