IEC 80601-2-71:2025

FINAL DRAFT
International
Standard
IEC/FDIS
80601-2-71
ISO/TC 121/SC 3
Medical electrical equipment —
Secretariat: ANSI
Part 2-71:
Voting begins on:
2024-09-20
Particular requirements for
the basic safety and essential
Voting terminates on:
2024-11-15
performance of functional near-
infrared spectroscopy (functional
NIRS) equipment
Appareils électromédicaux —
Partie 2-71: Exigences particulières pour la sécurité de base
et les performances essentielles des appareils d'imagerie
spectroscopique proche infrarouge (NIRS)
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
This draft is submitted to a parallel vote in ISO and in IEC.
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
IEC/FDIS 80601-2-71:2024(en) © IEC 2024

FINAL DRAFT
IEC/FDIS 80601-2-71:2024(en)
International
Standard
IEC/FDIS
80601-2-71
ISO/TC 121/SC 3
Medical electrical equipment —
Secretariat: ANSI
Part 2-71:
Voting begins on:
Particular requirements for
2024-09-20
the basic safety and essential
Voting terminates on:
2024-11-15
performance of functional near-
infrared spectroscopy (functional
NIRS) equipment
Appareils électromédicaux —
Partie 2-71: Exigences particulières pour la sécurité de base
et les performances essentielles des appareils d'imagerie
spectroscopique proche infrarouge (NIRS)
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2024
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
This draft is submitted to a parallel vote in ISO and in IEC.
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
IEC/FDIS 80601-2-71:2024(en) © IEC 2024

© IEC 2024 – All rights reserved
ii
– 2 – IEC FDIS 80601-2-71 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
201.1 Scope, object and related standards . 8
201.2 Normative references . 10
201.3 Terms and definitions . 10
201.4 General requirements . 14
201.5 General requirements for testing ME EQUIPMENT . 14
201.6 Classification of ME EQUIPMENT and ME SYSTEMS . 14
201.7 ME EQUIPMENT identification, MARKING and documents . 14
201.8 Protection against electrical HAZARDS from ME EQUIPMENT . 15
201.9 Protection against MECHANICAL HAZARDS of ME EQUIPMENT and ME SYSTEMS. 16
201.10 Protection against unwanted and excessive radiation HAZARDS . 16
201.11 Protection against excessive temperatures and other HAZARDS . 16
201.12 Accuracy of controls and instruments and protection against hazardous
outputs . 18
201.13 HAZARDOUS SITUATIONS and fault conditions for ME EQUIPMENT. 28
201.14 PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS) . 28
201.15 Construction of ME EQUIPMENT . 28
201.16 ME SYSTEMS . 29
201.17 Electromagnetic compatibility of ME EQUIPMENT and ME SYSTEMS . 29
201.101 Requirements for the FUNCTIONAL NIRS EQUIPMENT ACCESSORIES . 29
202 Electromagnetic disturbances – Requirements and tests . 29
206 Useability . 30
Annexes . 31
Annex C (informative) Guide to MARKING and labelling requirements for ME EQUIPMENT
and ME SYSTEMS . 32
Annex AA (informative) Particular guidance and rationale . 34
ANNEX BB (normative) Evaluating ME EQUIPMENT performance using the FUNCTIONAL
NIRS PHANTOM . 38
ANNEX CC (informative) Skin temperature at the FUNCTIONAL NIRS PROBE . 47
Annex DD (informative) Reference to the IMDRF essential principles and labelling
guidance . 48
Bibliography . 50
Index of defined terms . 54

Figure 201.101 – FULL WIDTH AT HALF MAXIMUM OF SPECTRAL POWER DISTRIBUTION . 11
Figure 201.102 – Measurement of the AVERAGE OPTICAL POWER. 19
Figure 201.103 – Measurement of PEAK WAVELENGTH and FWHM . 20
Figure 201.104 – Measurement of the signal stability . 21
Figure 201.105 – Measurement of the RESPONSE TIME . 22
Figure 201.106 – Rise time and fall time in the RESPONSE TIME . 23

IEC FDIS 80601-2-71 © IEC 2024 – 3 –
Figure 201.107 – Measurement of the signal-to-noise ratio of the detected light
intensity . 24
Figure 201.108 – Measurement of signal-to-noise ratio of the PATHLENGTH-DEPENDENT
............................................................................................................ 26
HAEMOGLOBIN CHANGE
Figure 201.109 – Measurement of SIGNAL CROSS-TALK . 27
Figure BB.1 – The FUNCTIONAL NIRS PHANTOM in two states with different detected light
intensities . 41
Figure BB.2 – FUNCTIONAL NIRS PHANTOM measurement using the reference system . 42
Figure BB.3 – FUNCTIONAL NIRS PHANTOM measurement using the ME EQUIPMENT to be
evaluated . 42
Figure BB.4 – Schematic for measurement of OPTICAL LOSS . 46

Table 201.101 ─ Distributed ESSENTIAL PERFORMANCE requirements . 14
Table 201.102 – Performance tests employing the FUNCTIONAL NIRS EQUIPMENT or
attenuator and the required OPTICAL LOSS . 18
Table 201.C.101 – MARKING on the outside of FUNCTIONAL NIRS EQUIPMENT or their parts . 32
Table 201.C.102 – ACCOMPANYING DOCUMENTS general . 32
Table 201.C.103 – INSTRUCTIONS FOR USE . 33
Table 201.C.104 – TECHNICAL DESCRIPTION . 33
Table DD.1 – Correspondence between this document and the IMDRF essential
principles . 48
Table DD.2 – Correspondence between this document and the IMDRF labelling
principles . 49

– 4 – IEC FDIS 80601-2-71 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-71: Particular requirements for
the basic safety and essential performance of
functional near-infrared spectroscopy (NIRS) equipment

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC and ISO draw attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC and ISO take no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, IEC and ISO had not received notice of
(a) patent(s), which may be required to implement this document. However, implementers are cautioned that this
may not represent the latest information, which may be obtained from the patent database available at
https://patents.iec.ch and www.iso.org/patents. IEC and ISO shall not be held responsible for identifying any or
all such patent rights.
IEC 80601-2-71 has been prepared by a Joint Working Group of IEC subcommittee 62D:
Particular medical equipment, software, and systems, of IEC technical committee 62: Medical
equipment, software, and systems, and ISO subcommittee SC3: Respiratory devices and
related equipment used for patient care, of ISO technical committee 121: Anaesthetic and
respiratory equipment. It is an International Standard.
This second edition cancels and replaces the first edition published in 2015. This edition
constitutes a technical revision.

IEC FDIS 80601-2-71 © IEC 2024 – 5 –
This edition includes the following significant technical changes with respect to the previous
edition:
a) alignment with IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012,
IEC 60601-1:2005/AMD2:2020, IEC 60601-1-8:2006, IEC 60601-1-8:2006/AMD1:2012,
IEC 60601-1-8:2006/AMD2:2020, IEC 60601-1-2:2014, IEC 60601-1-2:2014/AMD1:2020,
IEC 60601-1-6:2010, IEC 60601-1-6:2010/AMD1:2013 and
IEC 60601-1-6:2010/AMD2:2020;
b) added requirements for ESSENTIAL PERFORMANCE;
c) added requirements for PRIMARY OPERATING FUNCTIONS;
d) added requirements for protection against excessive temperatures;
e) added requirements for the display legibility for OPERATORS wearing personal protective
equipment;
f) harmonization with ISO 20417, where appropriate.
This publication is published as a double logo standard.
The text of this International Standard is based on the following documents of IEC:
Draft Report on voting
62D/XXX/FDIS 62D/XXX/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table. In ISO, the document was approved by XXX P members out of YYY having
cast a vote.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
In this document, the following print types are used:
– requirements and definitions: roman type.
– test specifications: italic type.
– informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS defined in Clause 3 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 AND
IEC 60601-1:2005/AMD2:2020, IN THIS DOCUMENT OR AS NOTED: SMALL CAPITALS.
In referring to the structure of this document, the term
– "clause" means one of the seventeen numbered divisions within the table of contents,
inclusive of all subdivisions (e.g. Clause 7 includes subclauses 7.1, 7.2, etc.);
– "subclause" means a numbered subdivision of a clause (e.g. 7.1, 7.2 and 7.2.1 are all
subclauses of Clause 7).
References to clauses within this document are preceded by the term "Clause" followed by the
clause number. References to subclauses within this particular standard are by number only.
In this document, the conjunctive "or" is used as an "inclusive or" so a statement is true if any
combination of the conditions is true.

– 6 – IEC FDIS 80601-2-71 © IEC 2024
The verbal forms used in this document conform to usage described in Clause 7 of the ISO/IEC
Directives, Part 2. For the purposes of this document, the auxiliary verb:
– "shall" means that compliance with a requirement or a test is mandatory for compliance with
this document;
– "should" means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this document;
– "may" is used to describe a permissible way to achieve compliance with a requirement or
test.
An asterisk (*) as the first character of a title or at the beginning of a paragraph or table title
indicates that there is guidance or rationale related to that item in Annex AA.
A list of all parts of the IEC 60601 and IEC 80601 series, published under the general title
Medical electrical equipment, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
NOTE The attention of the users of this document is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised IEC or
ISO publication in which to make products in accordance with the new requirements and to equip themselves for
conducting new or revised tests. It is the recommendation of the committees that the content of this publication be
adopted for implementation nationally not earlier than 3 years from the date of publication.

IEC FDIS 80601-2-71 © IEC 2024 – 7 –
INTRODUCTION
The minimum safety requirements specified in this document are considered to provide for a
practical degree of safety in the operation of FUNCTIONAL NIRS EQUIPMENT.
The requirements are followed by specifications for the relevant tests.
A "Particular guidance and rationale" text giving some explanatory notes, where appropriate,
about the more important requirements is included in Annex AA. It is considered that knowledge
of the reasons for these requirements will not only facilitate the proper application of the
standard but will, in due course, expedite any revision necessitated by changes in clinical
practice or as a result of developments in technology. However, this annex does not form part
of the requirements of this document.

– 8 – IEC FDIS 80601-2-71 © IEC 2024
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-71: Particular requirements for
the basic safety and essential performance of
functional near-infrared spectroscopy (NIRS) equipment

201.1 Scope, object and related standards
Clause 1 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
201.1.1 Scope
Replacement:
This part of IEC 80601 applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of FUNCTIONAL
NIRS EQUIPMENT, as defined in 201.3.205, intended to be used by itself, or as a part of an ME
SYSTEM hereinafter referred to as ME EQUIPMENT.
HAZARDS inherent in the intended physiological function of ME EQUIPMENT or ME SYSTEMS within
the scope of this document are not covered by specific requirements in this document except
in IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020,
7.2.13 and 8.4.1.
NOTE Additional information can be found in IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020, 4.2.
This document is not applicable to
– equipment for the measurement of oxygen saturation of the haemoglobin in the micro
vessels (capillaries, arterioles and venules), i.e. tissue oximeters;
– frequency-domain and time-domain equipment for functional near-infrared spectroscopy;
– equipment for the measurement of changes in the concentration of chromophores other than
oxy- and deoxy-haemoglobin;
– equipment for the measurement of changes in the concentration of oxy- and deoxy-
haemoglobin in tissues other than the brain.
This document does not specify the requirements for:
– cerebral tissue oximeter equipment, which are given in ISO 80601-2-85 [1] ; and
– pulse oximeter equipment, which are given in ISO 80601-2-61 [2].
201.1.2 Object
Replacement:
The object of this document is to establish particular BASIC SAFETY and ESSENTIAL PERFORMANCE
requirements for FUNCTIONAL NIRS EQUIPMENT as defined in 201.3.205.
NOTE This document has been prepared to address the relevant essential principles [3] and labelling principles [4]
of the International Medical Devices Regulators Forum (IMDRF) as indicated in Annex DD.
___________
Numbers in square brackets refer to the Bibliography.

IEC FDIS 80601-2-71 © IEC 2024 – 9 –
201.1.3 Collateral standards
Addition:
This document refers to those applicable collateral standards that are listed in Clause 2 of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 and
Clause 201.2 of this document.
IEC 60601-1-3 and IEC 60601-1-10 [5] do not apply. All other published collateral standards in
the IEC 60601-1 series apply as published.
201.1.4 Particular standards
Addition:
In the IEC 60601 series, particular standards may modify, replace or delete requirements
contained in IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020, including the collateral standards, as appropriate for the
particular ME EQUIPMENT under consideration, and may add other BASIC SAFETY or ESSENTIAL
PERFORMANCE requirements.
A requirement of a particular standard takes priority over IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 and applicable collateral
standards.
The numbering of clauses and subclauses of this particular standard corresponds to that of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 with the
prefix "201" (e.g. 201.1 in this document addresses the content of Clause 1 of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020) or
applicable collateral standard with the prefix "20x" where x is the final digit(s) of the collateral
standard document number (e.g. 202.4 in this document addresses the content of Clause 4 of
the IEC 60601-1-2 collateral standard, 203.6 in this document addresses the content of
Clause 6 of the IEC 60601-1-3 collateral standard, etc.). The changes to the text of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 are
specified by the use of the following words:
"Replacement" means that the clause or subclause of IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or applicable collateral
standard is replaced completely by the text of this document.
"Addition" means that the text of this document additional to the requirements of
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or
applicable collateral standard.
"Amendment" means that the clause or subclause of IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or applicable collateral
standard is amended as indicated by the text of this document.
Subclauses, figures or tables which are additional to those of IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 are numbered starting from
201.101. However due to the fact that definitions in IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 are numbered 3.1 through
3.154, additional definitions in this document are numbered beginning from 201.3.201.
Additional annexes are lettered AA, BB, etc., and additional items aa), bb), etc.
Subclauses, figures or tables which are additional to those of a collateral standard are
numbered starting from 20x, where "x" is the number of the collateral standard, e.g. 202 for
IEC 60601-1-2, 203 for IEC 60601-1-3, etc.

– 10 – IEC FDIS 80601-2-71 © IEC 2024
Where there is no corresponding clause or subclause in this document, the clause or subclause
of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 or
applicable collateral standard, although possibly not relevant, applies without modification;
where it is intended that any part of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 or applicable collateral standard, although possibly relevant, is
not to be applied, a statement to that effect is given in this document.
201.2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
Clause 2 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
Addition:
IEC 60601-1:2005, Medical electrical equipment – Part 1: General requirements for basic safety
and essential performance
IEC 60601-1:2005/AMD1:2012
IEC 60601-1:2005/AMD2:2020
IEC 60825-1:2014, Safety of laser products – Part 1: Equipment classification and requirements
IEC 62471:2006, Photobiological safety of lamps and lamp systems
IEC 62570:2014, Standard practice for marking medical devices and other items for safety in
the magnetic resonance environment
ISO 17664-1:2021, Processing of health care products – Information to be provided by the
medical device manufacturer for the processing of medical devices – Part 1: Critical and semi-
critical medical devices
ISO 17664-2:2021, Processing of health care products – Information to be provided by the
medical device manufacturer for the processing of medical devices – Part 2: Non-critical
medical devices
ISO 20417:2021, Medical devices – Information to be supplied by the manufacturer
201.3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012, IEC 60601-1:2005/AMD2:2020, ISO 17664-2:2021,
ISO 20417:2021 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp

IEC FDIS 80601-2-71 © IEC 2024 – 11 –
201.3.201
AVERAGE OPTICAL POWER
temporal average power of continuous light or repeated light pulses from each discrete
wavelength, from the EMITTER OPTODE connected to the FUNCTIONAL NIRS MONITOR
201.3.202
DETECTOR OPTODE
part of the FUNCTIONAL NIRS PROBE which detects light from the living tissue that forms part of
the APPLIED PART
2201.3.203
EMITTER OPTODE
part of the FUNCTIONAL NIRS PROBE which emits light to the living tissue that forms part of the
APPLIED PART
Note 1 to entry: An EMITTER OPTODE can contain two or more light sources (e.g. laser diodes or light-emitting
diodes) operating at different NOMINAL wavelengths.
201.3.204
FWHM
FULL WIDTH AT HALF MAXIMUM OF SPECTRAL POWER DISTRIBUTION
difference of the wavelength between the two points whose corresponding power values are
equal and 3 dB lower than the values at each PEAK WAVELENGTH
Note 1 to entry: FWHM is a measure of the width of the spectral power distribution emitted by the EMITTER OPTODE
connected to the FUNCTIONAL NIRS MONITOR. Figure 201.101 provides a visual representation. If there are more than
two wavelengths where power VALUE is 3 dB lower than the values at each PEAK WAVELENGTH, FWHM shall be
calculated from the difference between minimum and maximum wavelengths.

Figure 201.101 – FULL WIDTH AT HALF MAXIMUM OF SPECTRAL POWER DISTRIBUTION
201.3.205
FUNCTIONAL NIRS EQUIPMENT
FUNCTIONAL NEAR-INFRARED SPECTROSCOPY EQUIPMENT
ME EQUIPMENT that estimates PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGES in living tissue by
illuminating tissue with continuous light and detecting changes in the infrared and visible light
intensity diffusively reflected from the tissue

– 12 – IEC FDIS 80601-2-71 © IEC 2024
201.3.206
FUNCTIONAL NIRS MONITOR
FUNCTIONAL NEAR-INFRARED SPECTROSCOPY MONITOR
MONITOR
part of the FUNCTIONAL NIRS EQUIPMENT that encompasses the electronics, display and operator-
EMITTER OPTODES and DETECTOR OPTODES
equipment interface excluding the
Note 1 to entry: The FUNCTIONAL NIRS MONITOR typically encompasses the electronics, display and OPERATOR-
EQUIPMENT INTERFACE. It can consist of a separate control unit, a computer and a display. Electronics or a control
unit integrated in the APPLIED PART are not part of the FUNCTIONAL NIRS MONITOR.
201.3.207
FUNCTIONAL NIRS PROBE
FUNCTIONAL NEAR-INFRARED SPECTROSCOPY PROBE
PROBE
part of the functional NIRS EQUIPMENT that includes the APPLIED PART
Note 1 to entry: This definition of PROBE is consistent with the definition of PROBE for cerebral tissue oximeters as
given in ISO 80601-2-85.
Note 2 to entry: The PROBE contains single or multiple EMITTER OPTODES and DETECTOR OPTODES. A reflectance
PROBE design is the typical configuration.
201.3.208
FUNCTIONAL NIRS PHANTOM
apparatus that simulates a PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGE by giving the ME
EQUIPMENT a specified known change in attenuation to evaluate the difference between the
measured VALUE of the pseudo PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGE obtained from the
measurement on the phantom and the reference VALUE calculated from the attenuation change
Note 1 to entry: The FUNCTIONAL NIRS PHANTOM plays a role in determining the performance of FUNCTIONAL NIRS
EQUIPMENT, especially PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGE measurement. A description of the function
and specifications regarding the manufacturing of the FUNCTIONAL NIRS PHANTOM is found in Annex BB.
Note 2 to entry: A FUNCTIONAL NIRS PHANTOM is developed during design and is used at the time of inspection in
manufacturing or after being placed into service.
Note 3 to entry: The change in attenuation corresponds to a change in OPTICAL LOSS of the FUNCTIONAL NIRS
PHANTOM of the same magnitude.
201.3.209
MEASUREMENT CHANNEL
CHANNEL
combination of an EMITTER OPTODE and a DETECTOR OPTODE that provide an output
201.3.210
OPTICAL LOSS
ratio of the total optical power exiting the FUNCTIONAL NIRS PHANTOM or attenuator through a
specified aperture, to the optical power emitted by the EMITTER OPTODE connected to the
FUNCTIONAL NIRS MONITOR and placed on the entrance side of the FUNCTIONAL NIRS PHANTOM or
attenuator
–X/10
Note 1 to entry: The OPTICAL LOSS is denoted in dB. X dB OPTICAL LOSS is equivalent to 10 .
Note 2 to entry: The optical power exiting the EMITTER OPTODE and the FUNCTIONAL NIRS PHANTOM can be measured
with an optical power meter.
Note 3 to entry: For details of the measurement of the OPTICAL LOSS, refer to BB.3.3.
201.3.211
PATHLENGTH-DEPENDENT DEOXYHAEMOGLOBIN CHANGE
VALUE calculated from the changes in detected light intensities, equal to the product of the
apparent change in the concentration of DEOXYHAEMOGLOBIN and the mean optical pathlength

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201.3.212
PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGE
∆c∙L
collective term which signifies the product of apparent haemoglobin concentration change and
the mean optical pathlength inclusive of two chromophores (OXYHAEMOGLOBIN and
DEOXYHAEMOGLOBIN), as well as total haemoglobin
Note 1 to entry: The calculation of the PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGE from measured changes in
attenuation based on the multivariate modified Beer-Lambert law is described in BB.2.
Note 2 to entry: The concentration changes are termed "apparent" values since they are obtained from a
homogeneous model while the structure of the human head as well as the spatial distribution of haemoglobin
concentration changes are substantially heterogeneous.
Note 3 to entry: The total haemoglobin concentration is the sum of OXY- and DEOXYHAEMOGLOBIN concentrations.
201.3.213
PATHLENGTH-DEPENDENT OXYHAEMOGLOBIN CHANGE
VALUE calculated from the changes in detected light intensities, equal to the product of the
apparent change in the concentration of OXYHAEMOGLOBIN and the mean optical pathlength
Note 1 to entry: OXYHAEMOGLOBIN is the haemoglobin bonded with oxygen molecules.
201.3.214
PEAK WAVELENGTH
wavelength where the power is the largest in the spectral power distribution for each of the
distinct NOMINAL wavelengths in the light radiated from the EMITTER OPTODE
201.3.215
PRIMARY OPERATING FUNCTION
function that involves user interaction that is related to the safety of the medical device
Note 1 to entry: Often a PRIMARY OPERATING FUNCTION is interacted with by a series of tasks that can be broken
down into a series of user interactions.
Note 2 to entry: The concept of safety includes loss or degradation of performance resulting in an unacceptable
RISK to the PATIENT, including use error that prevents the user from effectively using the medical device to achieve
its intended medical purpose. In IEC 60601-1, this is referred to as ESSENTIAL PERFORMANCE.
[SOURCE: IEC 62366-1:2015, 3.11]
201.3.216
RESPONSE TIME
time required for the step response of the ME EQUIPMENT to move from its specified percentage
of the final steady-state VALUE to the other specified percentage
Note 1 to entry: The RESPONSE TIME is conventionally denoted by the rise time or fall time that represents the interval
between the times corresponding to 10 % and 90 % of the step response amplitude during the transition. See also
201.12.1.101.7 and Figure 201.106.
201.3.217
SIGNAL CROSS-TALK
signal contamination or interference from other light sources of the same or other EMITTER
OPTODES to the relevant CHANNEL

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201.4 General requirements
Clause 4 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
Additional subclause:
201.4.3.101 * Additional requirements for ESSENTIAL PERFORMANCE
Table 201.101 indicates the ESSENTIAL PERFORMANCE of FUNCTIONAL NIRS EQUIPMENT, unless the
MANUFACTURER identifies through their RISK MANAGEMENT PROCESS that the FUNCTIONAL NIRS
EQUIPMENT has no ESSENTIAL PERFORMANCE.
Table 201.101 ─ Distributed ESSENTIAL PERFORMANCE requirements
Requirement Subclause
a
Adequate reproduction of the temporal profiles of the PATHLENGTH-DEPENDENT

HAEMOGLOBIN CHANGES
or generation of an ALARM CONDITION
low signal of detected light intensity 201.12.1.101.11
high signal of detected light intensity 201.12.1.101.11
a
Subclause 202.8.1.101 indicates methods of evaluating the adequate reproduction of the temporal profiles of
the PATHLENGTH-DEPENDENT HAEMOGLOBIN CHANGES as acceptance criteria following specific tests required by
this document.
201.5 General requirements for testing ME EQUIPMENT
Clause 5 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies.
201.6 Classification of ME EQUIPMENT and ME SYSTEMS
Clause 6 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies.
201.7 ME EQUIPMENT identification, MARKING and documents
Clause 7 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
Additional subclauses:
201.7.1.101 Information to be supplied by the MANUFACTURER
a) The INFORMATION SUPPLIED BY THE MANUFACTURER of FUNCTIONAL NIRS EQUIPMENT and its
accessories shall conform with ISO 20417:2021.
b) In applying ISO 20417:2021, the terms in this document and those in IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020 shall be used as follows.
1) The term "ACCOMPANYING INFORMATION" shall assume the same meaning as
ACCOMPANYING DOCUMENTS.
2) The term "MEDICAL DEVICE" shall assume the same meaning as ME EQUIPMENT.
3) The term "USER" shall assume the same meaning as OPERATOR.
4) The term "PATIENT" shall include animals.

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Check conformance by application of ISO 20417:2021.
201.7.2.4.101 Additional requirements for ACCESSORIES
a) ACCESSORIES supplied separately shall:
1) fulfil the requirements of 201.101.1; and
2) be MARKED with an indication of any limitations or adverse effects of the ACCESSORY on
BASIC SAFETY or ESSENTIAL PERFORMANCE of the FUNCTIONAL NIRS EQUIPMENT, if
the
applicable. See also 201.7.2.101.
b) If MARKING the ACCESSORY is not practicable, this information can be placed in the
INSTRUCTIONS FOR USE.
RISK MANAGEMENT FILE for any limitations or
Check conformity by inspection, inspection of the
adverse effects of the ACCESSORY, and where applicable, inspection of the INSTRUCTIONS FOR
USE.
201.7.2.101 Additional requirements for MARKING on the outside of ME EQUIPMENT or ME
EQUIPMENT parts
a) The MARKING on the ME EQUIPMENT shall be CLEARLY LEGIBLE and shall include its
classification as specified in Clause 7 of IEC 60825-1:2014.
b) For FUNCTIONAL NIRS EQUIPMENT intended to be used in the magnetic resonance (MR)
OPERATOR-accessible parts or ACCESSORIES of FUNCTIONAL NIRS EQUIPMENT
environment,
shall have CLEARLY LEGIBLE MARKINGS in accordance with IEC 62570:2014 of the following:
1) SYMBOL 7.3.1 of IEC 62570:2014 Table 1 and Figures 1 and 2 for colour, Table 2 and
Figures 3 and 4 for black and white) for an 'MR Safe' FUNCTIONAL NIRS EQUIPMENT, or
2) SYMBOL 7.3.2 of IEC 62570:2014 (Table 1 and Figure 5 for colour, Table 2 and Figure 6
for black and white) for an 'MR Conditional' FUNCTIONAL NIRS EQUIPMENT.
Check conformity by inspection.
201.7.9.2.1 General
Amendment (add as fifth bullet following the first paragraph):
– the intended position of the operator.
Additional subclause:
201.7.9.2.14.101 Additional requirements for ACCESSORIES, supplementary equipment,
used material
The INSTRUCTIONS FOR USE of the FUNCTIONAL NIRS EQUIPMENT shall identify at least one set of
ACCESSORIES necessary for the FUNCTIONAL NIRS EQUIPMENT'S INTENDED USE.
Check conformity by inspection.
201.8 Protection against electrical HAZARDS from ME EQUIPMENT
Clause 8 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
Additional subclause:
201.8.3.101 Additional requirements for classification of APPLIED PARTS
The APPLIED PARTS of the FUNCTIONAL NIRS EQUIPMENT shall be TYPE BF or TYPE CF APPLIED PARTS.

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Check conformance by inspection.
201.9 Protection against MECHANICAL HAZARDS of ME EQUIPMENT and ME SYSTEMS
Clause 9 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies.
201.10 Protection against unwanted and excessive radiation HAZARDS
Clause 10 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
201.10.4 Lasers
Replacement:
a) Depending on the light sources used in the EMITTER OPTODE, the FUNCTIONAL NIRS EQUIPMENT
shall comply with the relevant requirements of:
1) IEC 60825-1:2014; or
2) IEC 62471:2006.
NOTE IEC 60601-2-57[6] does not apply because there are no intended photobiological effects.
Check conformance by application of the requirements of IEC 60825-1:2014 or IEC 62471:2006,
as applicable.
201.11 Protection against excessive temperatures and other HAZARDS
Clause 11 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and
IEC 60601-1:2005/AMD2:2020 applies, except as follows.
201.11.1.2.2 APPLIED PARTS not intended to supply heat to a PATIENT
Amendment (add at the end of 11.1.2.2):
a) The FUNCTIONAL NIRS PROBE-tissue interface shall be evaluated for each FUNCTIONAL NIRS
MONITOR and FUNCTIONAL NIRS PROBE indicated in the INSTRUCTIONS FOR USE.
1) The evaluation of the worst-case temperature rise shall take into consideration the
potential for tissue injury due to the combined effect of conduction from the PROBE and
photothermally induced temperature rise.
NOTE 1 Additional information is found in Annex CC.
b) If the surface temperature of the FUNCTIONAL NIRS PROBE at the tissue interface can exceed
41 °C, then:
1) the FUNCTIONAL NIRS PROBE shall have an OPERATOR-adjustable control for activating any
elevated temperature mode that exceeds 41 °C;
i) A deliberate sequence of OPERATOR actions shall be required to activate this mode.
ii) The INSTRUCTIONS FOR USE shall describe this sequence of OPERATOR actions.
2) the FUNCTIONAL NIRS EQUIPMENT shall provide a means to limit the duration of an elevated
temperature mode in excess of 41 °C;
i) The duration of the elevated temperature mode shall not exceed 4 h at 43 °C or 8 h
at 42 °C.
3) the INSTRUCTIONS FOR USE shall include a statement to the effect that the use of
temperature settings greater than 41 °C requires special attention to PATIENTS with
susceptible skin, such as neonates, geriatric PATIENTS or burn victims;

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4) the FUNCTIONAL NIRS EQUIPMENt shall indicate when it is in the elevated temperature
mode; and
5) the TECHNICAL DESCRIPTION shall describe the test method used to measure the maximum
FUNCTIONAL NIRS PROBE-tissue interface.
temperature at the
i) When performing the temperature measurements for the FUNCTIONAL NIRS PROBE-
tissue interface, as specified in IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012
and IEC 60601-1:2005/AMD2:2020, 11.1.3, the test method disclosed in the
TECHNICAL DESCRIPTION can be utilized.
NOTE 2 Additional information is found in CC.3.
201.11.1.3 Measurements
Amendment (add at the end of 11.1.3):
aa) Evaluate the FUNCTIONAL NIRS PROBE-tissue interface with the skin temperature initially at
35 ±1 °C.
201.11.6.6 CLEANING and DISINFECTION of ME EQUIPMENT and ME SYSTEM
Amendment (add additional requirement as the last requirement and replace the conformance
test):
a) Unless SINGLE USE, critical or semi-critical FUNCTIONAL NIRS PROBES shall be designed to
allow for CLEANING and DISINFECTION to reduce to acceptable levels the RISK of cross infection
of the next PATIENT.
b) PROCESSING instructions for critical or semi-critical FUNCTIONAL NIRS PROBES shall:
1) conform with ISO 17664-1:2021; and
2) be disclosed in the INSTRUCTIONS FOR USE.
c) FUNCTIONAL NIRS EQUIPMENT ENCLOSURES and unless SINGLE USE, non-critical FUNCTIONAL
NIRS PROBES shall be designed to allow for surface CLEANING and DISINFECTION to reduce to
acceptable levels the RISK of cross infection of the next PATIENT.
NOTE ISO 14159:2002 [7] provides guidance for the design of ENCLOSURES.
dd) PROCESSING instructions for FUNCTIONAL NIRS EQUIPMENT ENC
...