IEC 60601-2-33:2010/AMD2:2015

IEC 60601-2-33 ®
Edition 3.0 2015-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AM ENDMENT 2
AM ENDEMENT 2
Medical electrical equipment –
Part 2-33: Particular requirements for the basic safety and essential performance
of magnetic resonance equipment for medical diagnosis

Appareils électromédicaux –
Partie 2-33: Exigences particulières pour la sécurité de base et les performances
essentielles des appareils à résonance magnétique utilisés pour le diagnostic
médical
IEC 60601-2-33:2010-03/AMD2:2015-06(en-fr)

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IEC 60601-2-33 ®
Edition 3.0 2015-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AM ENDMENT 2
AM ENDEMENT 2
Medical electrical equipment –

Part 2-33: Particular requirements for the basic safety and essential performance

of magnetic resonance equipment for medical diagnosis

Appareils électromédicaux –
Partie 2-33: Exigences particulières pour la sécurité de base et les performances

essentielles des appareils à résonance magnétique utilisés pour le diagnostic

médical
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.55 ISBN 978-2-8322-2700-8

– 2 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
FOREWORD
This amendment has been prepared by subcommittee 62B: Diagnostic imaging equipment, of
IEC technical committee 62: Electrical equipment in medical practice.
The text of this amendment is based on the following documents:
FDIS Report on voting
62B/977/FDIS 62B/987/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
_____________
INTRODUCTION TO AMENDMENT 2
This Amendment 2 has been developed to increase the FIRST LEVEL CONTROLLED OPERATING
MODE limit for the static field from 4 T to 8 T taking into account FDA, ICNIRP and other peer
reviewed scientific literature. In addition, a non-compulsory option, FIXED PARAMETER
OPTION:BASIC (FPO:B), is introduced to limit RF and gradient field outputs (peak and RMS) for
scanning PATIENTS with MR conditional implants. Consequently, text is proposed for the
Instructions for use to guide users in scanning PATIENTS with MR conditional implants.
Furthermore, references to newly published collateral standards have been updated.
201.1.3 Collateral standards
Replace, in the first sentence of the second paragraph, the reference to "IEC 60601-1-2:2007"
with "IEC 60601-1-2:2014”.
201.2 Normative references
Replace, under “Replacement”, the reference to "IEC 60601-1-2:2007" with the following:

© IEC 2015
IEC 60601-1-2:2014, Medical electrical equipment – Part 1-2: General requirements for basic
safety and essential performance – Collateral standard: Electromagnetic disturbances –
Requirements and tests
Add, under “Replacement”, the following new references:
IEC 60601-1-6:2010, Medical electrical equipment – Part 1-6: General requirements for basic
safety and essential performance – Collateral standard: Usability
IEC 60601-1-6:2010/AMD1:2013
IEC 60601-1-8:2006, Medical electrical equipment – Part 1-8: General requirements for basic
safety and essential performance – Collateral standard: General requirements, tests and
guidance for alarm systems in medical electrical equipment and medical electrical systems
IEC 60601-1-8:2006/AMD1:2012
201.3 Terms and definitions
* 201.3.201
B rms
1+
Delete, in the first line of the definition, “the MR relevant radiofrequency magnetic induction”.
Replace, in the last line of the definition, “evaluation time” with “integration time”.
Replace, in the last line of the definition “, and is estimated at the RF transmit coil centre”
with “, which shall be any 10 s period over the duration of the entire sequence”
Add the following new note to entry:
Note 1 to entry: B is derived from the flip angle averaged over an adjustment volume, which is typically
1+
represented by the axial central slab wherein MR signal is generated.
201.3.203
CONTROLLED ACCESS AREA
Replace the existing text of the definition with the following:
area around the MR SYSTEM, to which access is controlled to prevent HARM from the magnetic
field
Note 1 to entry: The CONTROLLED ACCESS AREA is not identical to the SPECIAL ENVIRONMENT or SPECIAL LOCATION
as defined in IEC 60601-1-2:2014.
201.3.234
TIME RATE OF CHANGE OF THE MAGNETIC FIELD
dB/dt
Add, at the end of the definition, the following note to entry:
Note 1 to entry: The time rate of change of the magnetic field dB/dt is assumed to be evaluated in a suitably low
frequency range (e.g. < 5 kHz) to disregard effects of switching amplifier ripple.
Add the following new terms:
201.3.242
FIXED PARAMETER OPTION
FPO
option within existing modes (i.e. NORMAL OPERATING MODE or FIRST LEVEL CONTROLLED
OPERATING MODE), which specifies a set of operational limit values for the allowable RF field
and GRADIENT OUTPUT and the specified B of the MR EQUIPMENT in a MR EXAMINATION
– 4 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
201.3.243
FIXED PARAMETER OPTION:BASIC
FPO:B
“basic” denotes a specific implementation of FPO, exclusively for 1,5 T MR SYSTEMS
Note 1 to entry: The note to entry in French concerning the source of the abbreviation “FPO:B” concerns the French
text only.
201.3.244
B
1+
component of the RF field in the rotating frame that is effective for tilting of the nuclear
magnetization
201.3.245
B PEAK
1+
peak amplitude of B
1+
* 201.3.246
(|dB/dt| PEAK)
FPO
maximum time rate of change of the magnitude of the magnetic field during the MR
EXAMINATION, evaluated at the location defined for FPO, i.e. a surface providing 5 cm clearance
to the outline of the PATIENT accessible volume
* 201.3.247
(|dB/dt| RMS)
FPO
root mean square (rms) of the magnitude of the time rate of change of the magnetic field for
FPO
t
x dB
FPO
dt
| |
( )
∫
dB
dt
(| | RMS) =
FPO
dt t
x
Where t is time, and t is the integration time. dB /dt is a conservative model estimate of
x FPO
the magnetic field associated with the switching gradients
201.3.248
SLEW PERCENTAGE
fraction of time that any gradient is slewing at any rate
201.3.249
CIRCULARLY POLARIZED RF
RF excitation where the two principal electromagnetic modes of the VOLUME RF TRANSMIT COIL
are driven with equal amplitude and 90° phase difference
Note 1 to entry: This drive operation is denoted as “CP” on user interfaces and in ACCOMPANYING DOCUMENTS.
Note 2 to entry: Circularly polarized RF is also commonly referred to as quadrature drive
* 201.3.250
SPATIAL FIELD GRADIENT
SFG

∇B
spatial rate of change of the main magnetic field , expressed in [T/m]
Note 1 to entry: Attractive magnetic forces on magnetisable or saturated ferromagnetic objects scale linearly with
SFG.
© IEC 2015
Note 2 to entry: The note to entry in French concerning the source of the abbreviation “SFG” concerns the French
text only.
Table 201.101 – List of symbols
Replace the existing title with the following:
Table 201.101 – List of symbols and abbreviations
201.7 ME EQUIPMENT identification, marking and documents
201.7.2 Marking on the outside of ME EQUIPMENT or ME EQUIPMENT parts
201.7.2.13 Physiological effects (safety signs and warning statements)
Replace, in the first sentence of the first paragraph, ”ISO 7010-W005 and ISO 7010-W006”
with ”ISO 7010-W005 (see Table 201.D.101, safety sign 1) and ISO 7010-W006 (see Table
201.D.101, safety sign 2)”
201.7.9 ACCOMPANYING DOCUMENTS
201.7.9.2 Instructions for use
* 201.7.9.2.101 Instructions for use for MR EQUIPMENT
* d) Exposure of the PATIENT and MR WORKER to excessive acoustic noise
Add, at the end of the only sentence in Note 1, ”(see Table 201.D.101, safety sign 6)”
* f) Liquid and gaseous cryogens
Add, between the first and second bullet points under the last dash, the following new note:
NOTE Applicable safety signs ISO 7010-M004 (see Table 201.D.101, safety sign 7) and ISO 7010-M009 (see
Table 201.D.101, safety sign 8) are appropriate for placement near the location where the cryogen refill is
performed.
* h) Exposure of the PATIENT and MR WORKER to the static magnetic field
Replace, in the 4th dash, “4 T” with “8 T”.
Replace, in the 8th dash, “4 T” with “8 T”.
* t) Scanning of PATIENTs with active or passive implants.
Replace the entire text of this item with the following:
The instructions for use shall declare that MR scanning is contra-indicated for PATIENTS with
implants, the exception being PATIENTS with known MR safe or MR conditional implants that
can be scanned according to the conditions specified in the implant labelling. The instructions
for use shall describe the following RISKS associated with the scanning of PATIENTS with active
or passive implants containing metal or other magnetic and/or electrically conductive
materials:
– the electromagnetic fields might exert strong forces on such implants;
– the electromagnetic fields might interfere with the operation of active devices;
– the implants might cause significant artefacts in the MR image;

– 6 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
– MR scanning when an implant is present might cause HARM such as internal heating that
results in tissue damage, loss of physiologic function and serious injury.
The instructions for use shall also address the following related to MR scanning of PATIENTS
with MR conditional implants:
– the MR scan should only be conducted based on the result of a risk versus benefit
assessment by the RESPONSIBLE ORGANIZATION;
– the MR OPERATOR shall adhere to the conditions of use defined in the MR conditional
implant labelling as described in the ACCOMPANYING DOCUMENTS of the implant
MANUFACTURER;
– the instructions for use shall include a statement to explain the roles and responsibilities
of the MR MANUFACTURER, the implant MANUFACTURER and the MR OPERATOR in scanning of
PATIENTS with MR conditional implants.
NOTE 8 Sample text is provided in Annex AA
w) About function
Replace the existing text of the second dash by the following:
– Maximum SPATIAL FIELD GRADIENT of the static magnetic field [T/m] outside the FIXED
magnet covers
NOTE Historical labeling practice for MR conditional devices uses G/cm where 1 T/m is equivalent to 100 G/cm.
Providing the conversion factor and/or the quantities in both units may be appropriate.
Add, after the second dash, the following new dash:
– Maximum spatial encoding gradient amplitude [mT/m] and maximum slew rate [T/m/s],
both specified on a per axis basis
Replace the final dash with the following:
– Maximum combined GRADIENT OUTPUT [T/s] on a cylinder with a diameter of 0,2 m, 0,4 m
and bore-diameter minus 0,1 m
Add, at the end of subclause 201.7.9.2.101, the following new item:
x) FPO (FIXED PARAMETER OPTION)
If the system has FPO capabilities, the following information shall be given:
– a statement that FPO limits the gradient and RF output in terms of dB/dt and B ;
1+
– a statement that FPO requires OPERATOR activation;
– instructions on how to activate FPO;
– a statement that FPO limits may be part of MR conditional medical device labelling and that
other scanning limits and/or PATIENT preparation may be required in addition to FPO to fully
comply with the implant device MR conditional labelling;
– a statement that FPO does not alter previously established operating modes, i.e. FPO can
work in NORMAL OPERATING MODE and FIRST LEVEL CONTROLLED OPERATING MODE;
– a statement indicating that FPO is for use with devices that have MR conditional labelling
that specifies FPO and the use of FPO when scanning PATIENTS with medical devices that
do not have FPO labelling is potentially hazardous and may cause serious injury or death.
201.7.9.3 Technical description
201.7.9.3.101 Technical description of MR EQUIPMENT
a) CONTROLLED ACCESS AREA
Replace this subtitle as follows:

© IEC 2015
a) CONTROLLED ACCESS AREA and SPECIAL ENVIRONMENT
Replace, in the first paragraph, “permanently attached” with “FIXED magnet”.
Delete, in the same paragraph, “and/or an electromagnetic interference level that does not
comply with IEC 60601-1-2, “.
Add, at the end of the first dash, “ the static magnetic fringe field strength shall not exceed
0,5 mT;”
Delete existing items 1) and 2).
Add, in the third dash, before the words “magnetic fields”, the word “static”.
Add, after the third dash, the following new paragraph:
For those parts of the MR EQUIPMENT that require installation in a SPECIAL ENVIRONMENT, to
ensure compliance with IEC 60601-1-2:2014, the technical description shall describe the need
for adequate RF shielding, including the presence of an RF door switch and interlock
mechanism preventing undue RF emissions and immunity.
Add, after the new paragraph, the following new note:
NOTE 5 See also 202.5.2.2.2
* b) Compatibility technical specification sheet
Replace, in the third bullet under the first dash, the existing text of the first sentence with the
following:
“The position in locations outside the FIXED magnet covers where SPATIAL FIELD GRADIENT
(SFG) is maximum, and the values of B and the SFG at that location.”
Replace, in the fourth bullet under the first dash, the existing text of the first sentence with the
following:
“The position in locations outside the FIXED magnet covers where the product of the
magnitude of the static magnetic field B and the SFG is maximum and the value of B and
0 0
SFG at that location.”
201.9 Protection against MECHANICAL HAZARDS of ME EQUIPMENT and ME SYSTEMS
201.9.8 HAZARDS associated with support systems
Replace the existing title of this subclause with the following:
201.9.8 MECHANICAL HAZARDS associated with support systems
Add the following new subclause:
201.9.8.3 Strength of PATIENT or OPERATOR support or suspension systems
201.9.8.3.3 Dynamic forces due to loading from persons
Addition:
Where it is determined that the dynamic loading test of the general standard applies, the
following provides an alternative means of compliance.

– 8 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
NOTE 1 The mass is accelerated for 150 mm, and then decelerates during compression of the 60 mm of foam,
resulting in a force equivalent from 2 to 3 times the SAFE WORKING LOAD.
Where mechanical analysis proves that the following static load test is more severe than the
dynamic load test specified in the general standard, it is possible to waive the dynamic load
test based on RISK MANAGEMENT.
Compliance is checked by the following test:
Prior to performing this test, a PATIENT support/suspension system is positioned horizontally in
its most disadvantageous position in NORMAL USE WHERE PATIENT loading and unloading takes
place.
A mass which results in a force calculated to be greater than the dynamic load shall be placed
on the PATIENT support. The contact area of this mass is equivalent to that defined in
Figure 33 of the general standard and is applied for at least one minute. Any loss of function
or structural damage that could result in unacceptable RISK constitutes a failure.
NOTE 2 The foam described in Figure 33 of the general standard is not required for this test.
201.12 Accuracy of controls and instruments and protection against hazardous
outputs
* 201.12.4 Protection against hazardous output
201.12.4.101 Operating modes
201.12.4.101.2 All operating modes
Add, at the end of this subclause:
d) The MR EQUIPMENT shall, on request, display “CP” on the CONTROL PANEL if CIRCULARLY
POLARIZED RF is used for the scan. For systems capable of other types of driving the
VOLUME RF TRANSMIT COIL, means shall be provided to the MR OPERATOR to select
CIRCULARLY POLARIZED RF. If selected, CIRCULARLY POLARIZED RF shall be active over the
entire examination.
* 201.12.4.103 Protection against excessive radio frequency energy
* 201.12.4.103.2 Limits for SAR
Table 201.105 – SAR limits for volume transmit coils
Replace, in the 8th row, 1st column “Long MR EXAMINATION specific absorbed energy” with “MR
EXAMINATION specific absorbed energy”
Replace, in the 8th row, 2nd column, the entire text with:
“The max. energy dose (SAR × examination time) shall be limited, subject to the RISK
MANAGEMENT.”
Replace Note 3 with:
NOTE 3 The MR EXAMINATION specific absorbed energy limitation has been introduced because very long duration
PATIENT studies have become more common. It limits either the MR EXAMINATION duration or the SAR level of the
individual scans of this MR EXAMINATION and is applicable to all SAR limits and all operating modes. If there are
multiple, separate studies on a given day where the PATIENT has been given a reasonable rest, each study is
considered to be independent from a MR EXAMINATION specific absorbed energy perspective.
* 201.12.4.104 Protection against exposure to static magnetic fields
Replace, in the first paragraph of item b), “4 T” with “8 T”.

© IEC 2015
Delete the second paragraph of item b).
Replace, in item c, “4 T” with “8 T”.
Replace, in the paragraph after item c) starting with “Physiological effects”, both instances of
“shall” with “should”.
Add the following new subclause:
* 201.12.4.106 Fixed limits to physical outputs of MR EQUIPMENT
201.12.4.106.1 General
Scanning of a PATIENT with a device which is labelled MR conditional could require controlled
outputs of the MR EQUIPMENT to less than the system capabilities. The MANUFACTURER of the
MR EQUIPMENT may implement a FIXED PARAMETER OPTION (FPO) for this purpose. If
implemented, FPO shall be designed to comply with all requirements of 201.12.4.106. FPO
shall not interfere with proper application of the evaluation and reporting of the operating
modes (see 201.12.4.101).
A system that has implemented FPO guarantees that the controlled outputs will not exceed the
specified values. The safety of an MR conditional implant labelled for FPO cannot be assessed
in a system running FPO.
201.12.4.106.2 Limit values
The following limits shall be applied to RF field and GRADIENT OUTPUT when the MR EQUIPMENT
is operated in the FPO. The set of values provided in Table 201.107 shall be called FPO:B.
NOTE 1 B denotes “basic”. This reflects the possibility to add another FPO at a later point in time with other limit
values than those defined in 201.107
Table 201.107 – FPO limits applicable for cylindrical MR SYSTEMS
Physical Parameter FPO:B
Nominal static magnetic field strength 1,5 T
Applicable coils Birdcage WHOLE BODY RF TRANSMIT COIL
Birdcage HEAD RF TRANSMIT COIL
CIRCULARLY POLARIZED RF shall be applied.
B PEAK
<= 30 µT
1+
B RMS <= 3,2 µT
1+
(|dB/dt| PEAK)
<= 100 T/s
FPO
(|dB/dt| RMS)
<= 56 T/s
FPO
NOTE 2 Cylindrical MR systems with elliptical PATIENT apertures can meet requirements for FPO:B.
201.12.4.106.3 User interface
The MR EQUIPMENT shall provide a means on the CONTROL PANEL to activate FPO during
PATIENT registration. While active, the user interface shall indicate that FPO is enabled and
give the FPO version (e.g. FPO:B). FPO:B will remain active for the remainder of the
examination until the next PATIENT registration.

– 10 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
*201.12.4.106.4 Implementation and demonstrating compliance for B PEAK
1+
The MR EQUIPMENT shall control the value of B PEAK for each RF pulse in every sequence,
1+
including adjustment sequences (prescan), not to exceed the values specified in Table
201.107.
Compliance is demonstrated by design review of the applied limits in the sequence pre-
calculation software, or by evaluation of pre-calculated B PEAK values for all RF pulses in
1+
sequences developed under FPO restrictions. Compliance shall be evaluated for all adjustment
sequences intended to be used with FPO enabled. In addition, run-time hardware and/or
software checks may be used in the MR EQUIPMENT to ensure that the actual B PEAK never
1+
exceeds the B PEAK values as specified in Table 201.107. A possible method to control
1+
B PEAK is described in the rationale.
1+
NOTE The spatially-localized amplitude of total B vector, especially in the off-centre position, may exceed the
nominal value of B PEAK by up to an order of magnitude.
1+
201.12.4.106.5 Implementation and demonstrating compliance for B RMS
1+
The MR EQUIPMENT shall control the value of B RMS for every sequence, including adjustment
1+
sequences (e.g. prescan), not to exceed the values specified in Table 201.107.
Compliance shall be demonstrated by design review.
NOTE The spatially-localized amplitude of total B RMS vector, especially in the off-centre position, may exceed
the nominal value of B RMS by up to an order of magnitude.
1+
201.12.4.106.6 Implementation and demonstrating compliance for (|dB/dt| PEAK)
FPO
The MR EQUIPMENT shall control the value of (|dB/dt| PEAK) whenever the gradient is
FPO
slewing, in every sequence, including adjustment sequences, not to exceed the values
specified in Table 201.107.
The values for (|dB/dt| PEAK) shall be controlled at a surface providing 5 cm clearance to
FPO
the outline of the PATIENT accessible volume.
The (|dB/dt| PEAK) value shall be calculated per sequence.
FPO
Compliance is demonstrated by application of calculation methods specified in
201.12.4.105.2.2 at the surface providing 5 cm clearance to the outline of the PATIENT
accessible volume. Based on symmetries, calculation in one octant of the gradient coil may be
sufficient to demonstrate compliance. Software validation for representative sequences shall
prove that calculated values do not exceed the value defined in Table 201.107. This can be a
measurement with a pick up coil at representative locations.
201.12.4.106.7 Implementation and demonstrating compliance for (|dB/dt| RMS)
FPO
The MR EQUIPMENT shall control the value of (|dB/dt| RMS) for every sequence, including
FPO
adjustment sequences, not to exceed the values specified in Table 201.107.The
MANUFACTURER shall select one of the following five tiers based on numerical evaluation of the
GRADIENT OUTPUT to implement control of (|dB/dt| RMS) .
FPO
a) Calculate maximum allowed SLEW PERCENTAGE using (|dB/dt| RMS) and (|dB/dt|
FPO
PEAK) from Table 201.107 where the relationship is (|dB/dt| RMS) = (|dB/dt|
FPO FPO
PEAK) *SQRT(SLEW PERCENTAGE). The MR EQUIPMENT shall ensure by evaluation of the
FPO
gradient waveforms that the actual SLEW PERCENTAGE in the sequence will not exceed the
maximum allowed SLEW PERCENTAGE.
b) Calculate peak |dB/dt| for each gradient slew using the method of 201.12.4.106.6,
determine the global maximum (|dB/dt| PEAK) of all gradient slews in the sequence,
FPO
and use that maximum to calculate (|dB/dt| RMS) = (|dB/dt| PEAK) *SQRT(SLEW
FPO FPO
© IEC 2015
PERCENTAGE), where the actual SLEW PERCENTAGE in the sequence is derived using
numerical evaluation of the sequence gradient waveform. The MR EQUIPMENT shall ensure
that (|dB/dt| RMS) does not exceed that value from Table 201.107.
FPO
c) Calculate peak |dB/dt| for each gradient slew using the method of 201.12.4.106.6. (|dB/dt|
RMS) shall be derived from a full integration of the values of peak |dB/dt| for the
FPO
individual slews, over the duration of the sequence. The MR EQUIPMENT shall ensure that
(|dB/dt| RMS) does not exceed that value from Table 201.107.
FPO
d) Calculate peak |dB/dt| for each gradient slew in all octants of the gradient coil. |dB/dt| RMS
shall be evaluated in each octant by full integration over the duration of the sequence of
peak |dB/dt| of every gradient slew. (|dB/dt| RMS) is the maximum of |dB/dt| RMS as
FPO
calculated in the individual octants. The MR EQUIPMENT shall ensure that (|dB/dt| RMS)
FPO
does not exceed that value from Table 201.107.
e) Calculate peak |dB/dt| between every gradient waveform control point in all octants of the
gradient coil. |dB/dt| RMS shall be evaluated in each octant by full integration over the
duration of the sequence. (|dB/dt| RMS) is the maximum of |dB/dt| RMS as calculated in
FPO
the individual octants. The MR EQUIPMENT shall ensure that (|dB/dt| RMS) does not
FPO
exceed that value from Table 201.107.
NOTE Each tier offers progressively more accuracy and sequence performance.
The (|dB/dt| RMS) evaluation interval shall not exceed 6 min. If the sequence exceeds 6
FPO
min, report the worst 6 min segment. If the sequence is less than 6 min, the (|dB/dt| RMS)
FPO
evaluation interval can be averaged over several sequences, but not to exceed 6 min.
Compliance is demonstrated by simulation of representative sequences.
* 202 Electromagnetic compatibility – Requirements and tests
Replace the entire existing text of the clause with the following:
IEC 60601-1-2:2014 applies except as follows:
202.2 Normative references
Amendment:
Delete the following normative references: IEC 60601-1-11:2010, IEC 60601-1-12, IEC 60601-
2-2:2009, IEC 60601-2-3:2012.
202.5 ME EQUIPMENT and ME SYSTEMS identification, marking and documents
202.5.1 Additional requirements for marking on the outside of ME EQUIPMENT and
ME SYSTEMS that are specified for use only in a shielded location SPECIAL
ENVIRONMENT
Replacement:
The SPECIAL ENVIRONMENT for the MR SYSTEM is defined as the room equipped with RF
shielding provisions containing the magnet, including the access door, penetration panels for
power and control cables, and an optional window. The RF shielding effectiveness of this
room shall be specified in the ACCOMPANYING DOCUMENTS.
202.5.2 ACCOMPANYING DOCUMENTS
202.5.2.1 Instructions for use
Amendment:
– 12 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
This subclause does not apply to the instructions for use but to the technical description of the
MR SYSTEM.
202.5.2.1.1 * General
Amendment:
Delete items c) and f).
202.5.2.2 Technical description
202.5.2.2.2 Requirements applicable to ME EQUIPMENT and ME SYSTEMS specified for
use only in a shielded location SPECIAL ENVIRONMENT
Amendment:
Delete item d).
Addition:
aa) recommended practices to help maintain the RF shielding effectiveness and integrity
of the RF shielded room for the EXPECTED SERVICE LIFE of the MR SYSTEM.
NOTE Examples of recommended practices include but are not limited to the following:
– periodic cleaning and inspection of the RF access door(s). RF shielding performance of access door(s) is
compromised if damaged or if dirt and debris is accumulated on the door perimeter;
– disallow any unauthorised electrical cables to enter the RF shielded room;
– disallow any unauthorised modifications to the RF shielded room.
202.7 ELECTROMAGNETIC EMISSIONS REQUIREMENTS FOR ME EQUIPMENT AND ME SYSTEMS
Addition:
202.7.101 ELECTROMAGNETIC EMISSIONS for MR EQUIPMENT
The MR EQUIPMENT outside the SPECIAL ENVIRONMENT shall comply with Clause 7 of
IEC 60601-1-2:2014.
Inside the SPECIAL ENVIRONMENT, Clause 7 of IEC 60601-1-2:2014 does not apply. The
requirements stated in 201.7.9.2.101 e) are applicable.
202.8 Electromagnetic IMMUNITY requirements FOR MR EQUIPMENT
Addition:
202.8.101 Electromagnetic IMMUNITY for MR EQUIPMENT
The MR EQUIPMENT outside the SPECIAL ENVIRONMENT shall comply with Clause 8 of
IEC 60601-1-2:2014.
All OPERATOR and PATIENT ACCESSIBLE PARTS of the MR EQUIPMENT in the SPECIAL ENVIRONMENT
shall comply with the ESD requirements in clause 8.1 of IEC 60601-1-2:2014.
The MANUFACTURER’S RISK MANAGEMENT PROCESS shall determine if components of the MR
EQUIPMENT used inside the SPECIAL ENVIRONMENT should comply with requirements of Clause 8
in order to maintain BASIC SAFETY and ESSENTIAL PERFORMANCE.
NOTE When selecting the immunity requirements inside the special environment, the manufacturer takes into
account the electromagnetic disturbances related to electromagnetic phenomena that could interfere with
provisions to ensure basic safety and essential performance.

© IEC 2015
Annex D Symbols on marking
Replace the entire existing text of the annex with the following:
Annex D of the general standard applies, except as follows:
Addition:
Additional safety signs and symbols that may be used for marking on or with MR SYSTEMS and
MR EQUIPMENT are found in Tables 201.D.101, 201.D.102 and 201.D.103.
Table 201.D.101 – MR safety signs
No. Safety sign Reference Title
1 ISO 7010-W005 Warning; Non-ionizing radiation

2 ISO 7010- W006 Warning; Magnetic field

No access for people with active implanted
3 ISO 7010-P007
cardiac devices
4 ISO 7010-P014 No access for people with metallic implants

5 ISO 7010-P008 No metallic articles or watches

– 14 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
No. Safety sign Reference Title
6 ISO 7010-M003 Wear ear protection

7 ISO 7010-M004 Wear eye protection

8 ISO 7010-M009 Wear protective gloves

The symbols shown in Table 201.D.102 may be used on RF coils to help identify the type of
coil it is.
© IEC 2015
Table 201.D.102 – RF coil symbols
No. Safety sign Safety sign (alternate) Reference Title
RF coil, transmit
NOTE The arrows may be in
IEC 60417-6191
red. The letter symbol T in
(2013-05)
red may be added adjacent to
the graphical symbol
RF coil, transmit and receive
NOTE The arrow heads
directed to the centre may be
in red, and those directed off-
IEC 60417-6192
centre may be in blue. The
(2013-05)
letter symbol T/R in red and
blue, respectively, may be
added adjacent to the
graphical symbol
RF coil, receive
NOTE The arrows may be in
IEC 60417-6193
blue. The letter symbol R in
(2013-05)
blue may be added adjacent
to the graphical symbol.
The symbols shown in Table 201.D.103 may be used on items that could be used in the
CONTROLLED ACCESS AREA. Additional information regarding the labelling requirements for
items that may be used in the CONTROLLED ACCESS AREA can be found in IEC 62570:2014
[144].
– 16 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
Table 201.D.103 – MR conditional symbols
No. Safety sign Reference Title

1 Or IEC 62570:2014 MR safe
MR conditional
NOTE For MR conditional items, additional
2 IEC 62570:2014
supplementary markings as defined in
IEC 62570:2014are required to identify the
conditions of use.
3 IEC 62570:2014 MR unsafe
NOTE When colour reproduction is not practical, the symbols in this table may be printed in black and white.
The use of the coloured symbols is strongly encouraged for the added visibility and information provided by the
colour.
Annex AA – Particular guidance and rationale
AA.1 Rationale for particular clauses and subclauses
Add the following three rationales:
Concerning 201.3.246 – (|dB/dt| peak)
FPO
The magnitude of TIME RATE OF CHANGE OF THE MAGNETIC FIELD |dB/dt| due to gradient
switching varies significantly as function of location inside the gradient coil. To protect MR
conditional devices that may be sensitive to gradient switching, the GRADIENT OUTPUT,
specifically |dB/dt|, must be evaluated for a sufficiently large volume inside the bore of the MR
SYSTEM. The required volume for evaluation of the GRADIENT OUTPUT for device interaction

© IEC 2015
(FPO) is typically bigger than the radius of the COMPLIANCE VOLUME appropriate for evaluation
of physiological effects (PNS OUTPUT), see 201.12.4.106.6.
|dB/dt| includes all vector field components of all GRADIENT UNITS. The peak value is derived
by evaluation of any slewing gradient in any part of the MR EXAMINATION at the location defined
for FPO, see 201.12.4.106.6. This peak value is particularly relevant to protect devices against
EMC issues and vibrations.
Concerning 201.3.247 – (|dB/dt| rms)
FPO
Protection of MR conditional devices against damage by gradient switching also requires a
root mean square limit for thermal issues. It is defined by the following formula
t
dB
x
FPO
dt
| |
( )
∫
dB dt
(| | RMS) =
FPO
dt t
x
where t is time, and t is the integration time. A multi-tier approach for the evaluation of –
x
(|dB/dt| rms) and this formula is defined in 201.12.4.106.7.
FPO
Concerning 201.3.250 SPATIAL FIELD GRADIENT (SFG)
The SPATIAL FIELD GRADIENT of the main field of the magnet (SFG) is given by
2 2

 
∂  ∂ ∂ 
2 2 2 2 2 2 2 2 2
SFG=∇B = B +B +B + B +B +B + B +B +B
     
x y z x y z x y z
∂x ∂y ∂z
   
 
The following derivation shows that this quantity is representative of the force exerted on a
ferromagnetic object or implant (neglecting torque).
A magnetizable object placed in the field of an MRI magnet will experience a net force. The
general formula for the total net force on an object of volume V is
      
F = (M⋅∇)BdV = (M∇B +M ∇B +M∇B)dV
x x y y z z
∫∫∫ ∫∫∫
V V
where F is the net force vector on the object, V the volume of the object, M the magnetization
vector, and B the magnetic field of the magnet. From this equation it can be seen that the
force depends directly on the gradients of B and not on the magnitude of B (in a homogenous
field, the net force is zero). However, indirectly the magnitude of B also enters the equation
because the magnetization M depends on B as the object is magnetized by the magnet. It
should be noted that M and B are both vectors that depend on the position in V. Further, M
and B in general have different directions. Although M is directly caused by B, there is no
direct relation between them, because the materials and shape of the object also play a role.
Analytical relations between M and B exist only for very specific cases, such as a linearly
magnetized sphere or a very thin rod. In short, evaluation of the equation for SFG is in general
difficult and requires numerical calculation with specialized software.
Although calculation of the exact force is difficult, estimation of the worst case force is
straightforward. A first approximation is that the size of the object is assumed to be small so
that it can be treated as a point source. In particular, the dimensions of the object shall be
smaller than the distance over which the gradients of B change substantially. In that case we
can speak about “the gradients” at the point where the object is located. In other words the

– 18 – IEC 60601-2-33:2010/AMD2:2015
© IEC 2015
field gradients indicated in the equation above can be considered constant over V and can
therefore be taken outside the integration. Also we can then evaluate M as a summation over
the volume leading to the so-called “magnetic moment” m of the object. One can consider m
as being the equivalent magnetic point dipole, like an infinitesimally small magnet, that
generates the same magnetic field as the actual magnetized object. The force is then given
by:
      
 ∂ ∂ ∂
F = (m⋅∇)B = m +m +m B = m∇B +m∇B +m∇B
 
x y z x x y y z z
∂x ∂y ∂z
 
or written in components of m and B, and using the fact that ∇B = 0 in volumes without
electrical current i.e. ∂Bx/∂y=∂By/∂x, ∂By/∂z=∂Bz/∂y, and ∂Bz/∂x=∂Bx/∂z:
∂B
  ∂B
 
∂B x ∂B 
   ∂B  y ∂B 
x x
x z
 
 
       
∂y
∂ ∂
∂x   z x
∂x   ∂x
F
         
x
 
∂B ∂B ∂B ∂B
  ∂B ∂B
 
 y y  y   y  
x z
F = m +m +m = m +m +m
 
y x y  z x y z
 
       
∂x ∂y ∂z ∂y ∂y ∂y
 
 
 
  
F     
∂B ∂B
 z
z ∂B z ∂B ∂B ∂B
z x y z
   
       
 
 
∂x ∂z
∂
  ∂y    ∂z   z 
 ∂z 
 
So we see that the force not only depends on all 9 spatial derivatives of B and the magnitude
of m, but also on the direction of m.
To further simplify the calculation, we assume that m has the same direction as B. This is a
critical assumption in the derivation which is justified because m is resulting from B, i.e. B
imposes the directionality of m. For lightly magnetic objects that are placed in the very strong
field of the MRI magnet, m and B are expected to have virtually identical directions in the first
place. Secondly, the object has the tendency to rotate in such a way that m becomes aligned
with B. So,
  

  
m B∇B +B∇B +B∇B

x x y y z z
F ≈ ( B⋅∇)B =m 
B B
or
   
B∇B +B∇B +B∇B
F
x x y y z z
≈


m
B
The value represented in this equation has the dimension of T/m, so this is effectively a
SPATIAL FIELD GRADIENT that expresses the magnitude of the force per unit of magnetic
moment.
For saturated objects, |m| is constant. The force is then proportional to the right-hand side of
the last equation. So, the right-hand side represents the SPATIAL FIELD GRADIENT. Note that the
first and last equations are indeed identical:
  
 B∇B +B∇B +B∇B
x x y y z z
∇B =

B
© IEC 2015
But it is unlikely that implants are magnetically saturated. To give an indication, saturated iron
objects already experience a 1 g force at low SPATIAL FIELD GRADIENTS of about 0,05 T/m. So,
implants made of such materials would always fail the 1 g test (ASTM F2052) in the MRI
magnet which has several T/m.
If the implant is made of non-mag
...