IEC 60601-2-68:2025

Medical electrical equipment - Part 2-68: Particular requirements for the basic safety and essential performance of X-ray-based image-guided radiotherapy equipment for use with electron accelerators, light ion beam therapy equipment and radionuclide beam therapy equipment

IEC 60601-2-68:2025 applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of X-ray based IMAGE-GUIDED RADIOTHERAPY equipment for use with EXTERNAL BEAM EQUIPMENT (EBE). This document covers safety aspects of kilovoltage (kV) and megavoltage (MV) X-ray imaging devices integrated in a specified geometrical relationship with EBE for the purpose of IGRT. It covers aspects of communication and relationships between the EXTERNAL BEAM EQUIPMENT and X-ray imaging devices, attached or not directly attached to, but in the same RADIATION shielded area as, and dedicated for use only with, the EXTERNAL BEAM EQUIPMENT. This document deals with equipment for OFFLINE X-IGRT, ONLINE X-IGRT and REAL-TIME X-IGRT. It covers procedures to reduce the risk of over-reliance on the X-IGRT EBE SYSTEM. For example, in the case of ONLINE X-IGRT, the MANUFACTURER will provide an interactive interface for user interaction with the correction suggested by the system. This document does not apply to CT SCANNERS, X-RAY EQUIPMENT for RADIOGRAPHY, and X-RAY EQUIPMENT for RADIOSCOPY, which are not intended for use for IGRT. Requirements that are being tested according to another standard can be identified by the manufacturer and if equivalent do not require retesting, instead evidence can refer to the CT SCANNER, X-RAY EQUIPMENT for RADIOGRAPHY, or X-RAY EQUIPMENT for RADIOSCOPY EQUIPMENT manufacturer's providing compliance statements or test reports. If the X-IGRT EQUIPMENT is combined with an MEE, any requirement that is the same for the X-IGRT EQUIPMENT and the MEE, such as a PATIENT POSITIONER, is not required to be tested twice, but can be accepted as tested by the MEE. This document applies for X-ray equipment for radiography, radioscopy, and COMPUTER tomography used for IGRT. If a clause or subclause is specifically intended to be applicable to X-IGRT EBE SYSTEMS, the content of that clause or subclause will say so. Where that is not the case, the clause or subclause applies only to X-IGRT EQUIPMENT.
This document, with the inclusion of TYPE TESTS and SITE TESTS, applies respectively to the MANUFACTURER and some installation aspects of X-IGRT EBE SYSTEMS intended to be:
• for NORMAL USE, operated under the authority of the RESPONSIBLE ORGANIZATION by QUALIFIED PERSONS having the required skills for a particular medical application, for particular specified clinical purposes, e.g., STATIONARY RADIOTHERAPY or MOVING BEAM RADIOTHERAPY,
• maintained in accordance with the recommendations given in the INSTRUCTIONS FOR USE, and
• subject to regular quality assurance performance and calibration checks by a QUALIFIED PERSON.
IEC 80601-2-68:2024 cancels and replaces the first edition published in 2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) alignment with the new editions of the relevant standards:
– IEC 60601-2-1:2020;
– IEC 60601-2-44:2009, IEC 60601-2-44:2009/AMD1:2012 and IEC 60601-2-44:2009/AMD2:2016;
– IEC 60601-2-64:2014;
b) clarification of the use of IEC 60601-2-68 for CT SCANNERS, X-RAY EQUIPMENT for RADIOGRAPHY and RADIOSCOPY used in the same room with an EXTERNAL BEAM EQUIPMENT (EBE);
c) introduction of updated requirements related to MECHANICAL HAZARDS, RADIATION HAZARDS, PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS), ACCOMPANYING DOCUMENTATION of an ME SYSTEM, and REMOTE OPERATION.

Appareils électromédicaux - Partie 2-68: Exigences particulières pour la sécurité de base et les performances essentielles des appareils de radiothérapie à rayonnement X assistée par imagerie médicale, destinés à être utilisés avec les accélérateurs d'électrons, les appareils de thérapie par faisceau d'ions légers et les appareils de thérapie par faisceau de radionucléides

L'IEC 60601-2-68:2025 s'applique à la SECURITE DE BASE et aux PERFORMANCES ESSENTIELLES des APPAREILS DE RADIOTHERAPIE A RAYONNEMENT X ASSISTEE PAR IMAGERIE MEDICALE destinés à être utilisés avec les APPAREILS DE RADIOTHERAPIE EXTERNES (EBE). Le présent document couvre les aspects de sécurité des dispositifs d'imagerie à rayonnement X sous kilotension (kV) et sous mégatension (MV) intégrés dans une relation géométrique spécifiée avec les EBE à des fins de RADIOTHERAPIE ASSISTEE PAR IMAGERIE MEDICALE. Il couvre les aspects de communication et les relations entre les APPAREILS DE RADIOTHERAPIE EXTERNES et les dispositifs d'imagerie à rayonnement X fixés ou non directement fixés, mais présents dans la même zone protégée contre le RAYONNEMENT que les APPAREILS DE RADIOTHERAPIE EXTERNES, et destinés à être utilisés uniquement avec ces appareils. Le présent document traite des APPAREILS DE RADIOTHERAPIE A RAYONNEMENT X ASSISTEE PAR IMAGERIE MEDICALE HORS LIGNE, EN LIGNE et EN TEMPS REEL. Il couvre les procédures de réduction du risque de confiance excessive envers le SYSTEME EBE X-IGRT. Par exemple, dans le cas d'une RADIOTHERAPIE A RAYONNEMENT X ASSISTEE PAR IMAGERIE MEDICALE EN LIGNE, le FABRICANT fournit une interface interactive destinée à l'interaction des utilisateurs avec la correction proposée par le système. Le présent document ne s'applique pas aux TOMODENSITOMETRES, aux APPAREILS A RAYONNEMENT X pour la RADIOGRAPHIE et aux APPAREILS A RAYONNEMENT X pour la RADIOSCOPIE, qui ne sont pas conçus pour être utilisés pour la RADIOTHERAPIE ASSISTEE PAR IMAGERIE MEDICALE. Les exigences soumises à l'essai conformément à une autre norme peuvent être identifiées par le fabricant. Lorsque ces exigences sont équivalentes, de nouveaux essais ne sont pas exigés, mais la conformité peut être prouvée par les déclarations de conformité ou les rapports d'essai relatifs aux TOMODENSITOMETRES, aux APPAREILS A RAYONNEMENT X pour la RADIOGRAPHIE ou aux APPAREILS A RAYONNEMENT X pour les APPAREILS DE RADIOSCOPIE fournis par le fabricant.
Lorsqu'un APPAREIL DE RADIOTHERAPIE A RAYONNEMENT X ASSISTEE PAR IMAGERIE MEDICALE est combiné à un APPAREIL ELECTROMEDICAL, toutes les exigences communes à l'APPAREIL DE RADIOTHERAPIE A RAYONNEMENT X ASSISTEE PAR IMAGERIE MEDICALE et à l'APPAREIL ELECTROMEDICAL (par exemple, un POSITIONNEUR DE PATIENT) n'ont pas besoin d'être soumises à l'essai deux fois, mais peuvent être admises comme ayant été soumises à l'essai par l'APPAREIL ELECTROMEDICAL. Le présent document s'applique aux APPAREILS A RAYONNEMENT X pour la RADIOGRAPHIE, la RADIOSCOPIE et la TOMODENSITOMETRIE utilisées pour la RADIOTHERAPIE ASSISTEE PAR IMAGERIE MEDICALE. Si un article ou un paragraphe est destiné spécifiquement à s'appliquer aux SYSTEMES EBE X IGRT, le contenu de cet article ou de ce paragraphe l'indique de manière explicite. Si tel n'est pas le cas, l'article ou le paragraphe s'applique uniquement aux APPAREILS X-IGRT.
Le présent document, y compris les ESSAIS DE TYPE et les ESSAIS SUR LE SITE, s'applique respectivement au FABRICANT et à certains aspects d'installation des SYSTEMES EBE X-IGRT destinés à être:
• pour une UTILISATION NORMALE, manipulés, sous la responsabilité de l'ORGANISME RESPONSABLE, par des PERSONNES QUALIFIEES qui disposent des compétences exigées pour une application médicale particulière, à des fins cliniques spécifiées particulières, par exemple RADIOTHERAPIE A CHAMP FIXE ou RADIOTHERAPIE CINETIQUE,
• entretenus selon les recommandations données dans les INSTRUCTIONS D'UTILISATION, et
• vérifiés périodiquement par une PERSONNE QUALIFIEE selon un programme d'assurance qualité qui porte sur le contrôle des performances et de l'étalonnage.
L'IEC 60601-2-68:2025 annule et remplace la première édition parue en 2014. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) alignement sur les nouvelles éditions des n

General Information

• Status: Published
• Publication Date: 03-Feb-2025
• ICS: 11.040.60 - Therapy equipment
• Technical Committee: SC 62C - Equipment for radiotherapy, nuclear medicine and radiation dosimetry
• Drafting Committee: WG 1 - TC 62/SC 62C/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 04-Feb-2025
• Completion Date: 10-Jan-2025

Relations

• Revises: IEC 60601-2-68:2014 - Medical electrical equipment - Part 2-68: Particular requirements for the basic safety and essential performance of X-ray-based image-guided radiotherapy equipment for use with electron accelerators, light ion beam therapy equipment and radionuclide beam therapy equipment
• Effective Date: 05-Sep-2023

Overview

IEC 60601-2-68:2025 is the 2nd edition international standard specifying the basic safety and essential performance requirements for X‑ray based Image‑Guided Radiotherapy (X‑IGRT) equipment used with External Beam Equipment (EBE) - including electron accelerators, light ion beam therapy and radionuclide beam therapy systems. It covers kilovoltage (kV) and megavoltage (MV) X‑ray imaging devices when used in a defined geometrical relationship with EBEs for IGRT, and applies to OFFLINE, ONLINE and REAL‑TIME X‑IGRT workflows.

Key topics and technical requirements

• Safety & essential performance: Requirements to minimise electrical, mechanical and radiation hazards and to ensure reliable imaging for treatment guidance.
• X‑IGRT imaging and workflows: Coverage of kV/MV imaging components, IGRT image acquisition, IGRT analysis and correction strategies for patient positioning and target localization.
• Communication & system relationships: Interfaces and interaction between the X‑ray imaging devices and the External Beam Equipment (EBE), including integration when devices are attached or co‑located in the same shielded treatment room.
• Risk of over‑reliance: Procedures and usability requirements to reduce over‑reliance on automated corrections; for ONLINE X‑IGRT the manufacturer must provide an interactive interface for user review and acceptance of suggested corrections.
• Testing requirements: Type tests (manufacturer responsibility) and site tests (installation aspects) to verify compliance, plus provisions for accepting equivalent test evidence from CT scanners, radiography or radioscopy equipment used for IGRT.
• Programmable Electrical Medical Systems (PEMS): Updated requirements for software control, PEMS safety and validation.
• Documentation & remote operation: Detailed accompanying documentation, Instructions for Use (IFU), usability considerations and guidance for operation from outside the facility.
• Quality assurance: Expectation that equipment will be operated by qualified personnel, maintained per IFU and subject to regular QA and calibration checks.

Applications and who uses this standard

• Manufacturers of X‑IGRT imaging systems and integrated IGRT‑EBE systems (design, testing, labeling, documentation).
• Regulatory and conformity assessors evaluating device safety and performance claims.
• Medical physicists, clinical engineers and hospital procurement teams specifying, installing and commissioning IGRT systems.
• Maintenance and QA teams implementing site tests, acceptance testing and ongoing calibration.

Benefits include improved patient safety, consistent IGRT performance, and clear manufacturer responsibilities for human‑machine interaction and system integration.

Related standards

• IEC 60601‑1 series (general ME equipment safety)
• IEC 60601‑2‑1:2020
• IEC 60601‑2‑44 (+AMD1/AMD2)
• IEC 60601‑2‑64:2014 These referenced IEC standards are aligned in this edition and provide complementary requirements for diagnostic CT, radiography and radioscopy when used in IGRT contexts.

Keywords: IEC 60601‑2‑68, image‑guided radiotherapy, IGRT, X‑IGRT, medical electrical equipment, kV, MV, external beam equipment, electron accelerator, light ion therapy, radionuclide beam therapy, PEMS, radiation protection, type tests, site tests.

Standards Content (Sample)

IEC 60601-2-68 ®
Edition 2.0 2025-02
REDLINE VERSION
INTERNATIONAL
STANDARD
Medical electrical equipment –
Part 2-68: Particular requirements for the basic safety and essential performance
of X-ray-based image-guided radiotherapy equipment for use with electron
accelerators, light ion beam therapy equipment and radionuclide beam therapy
equipment
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IEC 60601-2-68 ®
Edition 2.0 2025-02
REDLINE VERSION
INTERNATIONAL
STANDARD
Medical electrical equipment –
Part 2-68: Particular requirements for the basic safety and essential
performance of X-ray-based image-guided radiotherapy equipment for use with
electron accelerators, light ion beam therapy equipment and radionuclide beam
therapy equipment
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 11.040.60 ISBN 978-2-8327-0203-1

– 2 – IEC 60601-2-68:2025 RLV © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 2
201.1 Scope, object and related standards . 9
201.2 Normative references . 11
201.3 Terms and definitions . 13
201.4 General requirements . 23
201.5 General requirements for testing ME EQUIPMENT . 23
201.6 Classification of ME EQUIPMENT and ME SYSTEMS . 24
201.7 ME EQUIPMENT identification, marking and documents . 24
201.8 Protection against electrical HAZARDS from ME EQUIPMENT . 34
201.9 Protection against MECHANICAL HAZARDS of ME EQUIPMENT and ME SYSTEMS . 37
201.10 Protection against unwanted and excessive radiation HAZARDS . 46
201.11 Protection against excessive temperatures and other HAZARDS . 47
201.12 Accuracy of controls and instruments and protection against hazardous outputs . 48
201.13 Hazardous situations and fault conditions for ME EQUIPMENT . 48
201.14 PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS) . 49
201.15 Construction of ME EQUIPMENT . 50
201.16 ME SYSTEMS . 50
201.17 Electromagnetic compatibility of ME EQUIPMENT and ME SYSTEMS. 50
201.101 Reference data for X-IGRT . 51
201.102 X-IGRT imaging . 55
201.103 IGRT analysis and correction . 63
201.104 Operation of ME EQUIPMENT parts from outside the facility . 66
203 RADIATION protection in diagnostic X-RAY EQUIPMENT . 67
206 Usability . 69
Annexes . 70
Annex B (informative) Sequence of testing .
Annex A (informative) Sequence of testing. 71
Annex I (informative) ME SYSTEMS aspects . 72
Annex AA (informative) Particular guidance and rationale . 73
Annex BB (informative) Measuring CTDI . 76
free air
Bibliography . 77
Index of defined terms used in this document . 79

Figure AA.1 – Signals related to IGRT LATENCY . 74
Figure 201.101 – PATIENT SUPPORT movements .

Table 201.101 – Data required in the technical description . 27
Table 201.102 – Clauses and subclauses in this document that require the provision of
information in the ACCOMPANYING DOCUMENTS DOCUMENTATION, INSTRUCTIONS FOR USE
and the technical description . 29
Table 201.103 – Example test pattern for CTDI for kV . 60
free air
Table AA.1 – Clauses of the standard that contain requirements for X-IGRT IMAGING
COMPONENTS and related clauses of IEC 60601-2-44 and IEC 60601-2-54 with
equivalent requirements for CT SCANNER, x-RAY EQUIPMENT for RADIOGRAPHY, and X-RAY
EQUIPMENT for RADIOSCOPY . 73

– 4 – IEC 60601-2-68:2025 RLV © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-68: Particular requirements for the basic safety and essential
performance of X-ray-based image-guided radiotherapy equipment for use
with electron accelerators, light ion beam therapy equipment and
radionuclide beam therapy 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
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This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 60601-2-68:2014. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
IEC 60601-2-68 has been prepared by IEC subcommittee 62C: Equipment for radiotherapy,
nuclear medicine and radiation dosimetry, of IEC technical committee 62: Medical equipment,
software, and systems. It is an International Standard.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) alignment with the new editions of the relevant standards:
– IEC 60601-2-1:2020;
– IEC 60601-2-44:2009, IEC 60601-2-44:2009/AMD1:2012 and IEC 60601-2-
44:2009/AMD2:2016;
– IEC 60601-2-64:2014;
b) clarification of the use of IEC 60601-2-68 for CT SCANNERS, X-RAY EQUIPMENT for
RADIOGRAPHY and RADIOSCOPY used in the same room with an EXTERNAL BEAM EQUIPMENT
(EBE);
MECHANICAL HAZARDS, RADIATION HAZARDS,
c) introduction of updated requirements related to
PROGRAMMABLE ELECTRICAL MEDICAL SYSTEMS (PEMS), ACCOMPANYING DOCUMENTATION of an
ME SYSTEM, and REMOTE OPERATION.
The text of this International Standard is based on the following documents:
Draft Report on voting
62C/927/FDIS 62C/941/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
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 document are by number only.

– 6 – IEC 60601-2-68:2025 RLV © IEC 2025
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.
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 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.
INTRODUCTION
Modern RADIOTHERAPY practices utilize information from various imaging modalities, acquired
prior to initiating administration of the therapy, to plan the TREATMENT. The imaging provides
information about the location of the TARGET VOLUME and other anatomical features so that a
TREATMENT PLAN can be developed that provides an optimal dose distribution to have the best
chance of achieving the intended effect of TREATMENT while minimizing side effects.
However, difficulties arise when trying to administer the RADIATION, since TARGET
VOLUMES/critical structures are constantly moving within the body. For example, in parts of the
body moving with respiration, the TARGET VOLUMES/critical structures may change position or
shape during the RADIATION BEAM delivery throughout any given fraction. Furthermore, a course
of therapy may can extend over many days, during which the TARGET VOLUME/PATIENT may can
shrink or grow and/or move. Hence, the exact location of the TARGET VOLUME/critical structures
may can change between the time of TREATMENT PLANNING imaging and the actual administration
of a TREATMENT.
IMAGE-GUIDED RADIOTHERAPY (IGRT) combines planar or volumetric imaging during the course of
RADIOTHERAPY to adjust the TREATMENT delivery based on the PATIENT anatomy and PATIENT
position. This enables the OPERATOR AND/or EXTERNAL BEAM EQUIPMENT (EBE) to adjust the
RADIATION BEAM delivery based on the imaging information, such as the position of the TARGET
VOLUME, critical organs and/or other reference features, to compensate for anatomical changes
including internal organ motions and/or TREATMENT setup uncertainties. The increased accuracy
and precision achieved allows higher doses of RADIATION to be delivered to the TARGET VOLUME
and a reduction in the margin of healthy cells affected by the RADIATION. This is often used in
conjunction with other monitoring equipment.
This document establishes requirements to be complied with by MANUFACTURERS in the design
and construction of X-RAY IGRT EQUIPMENT (X-IGRT).
This document covers safety aspects of kilovoltage (kV) and megavoltage (MV) X-ray imaging
devices in a known geometrical relationship with an EXTERNAL BEAM EQUIPMENT such as an
ELECTRON ACCELERATOR, medical LIGHT ION BEAM MEDICAL ELECTRICAL EQUIPMENT or
RADIONUCLIDE BEAM THERAPY EQUIPMENT, for the purpose of IGRT. It covers aspects of
communication and relationships between the EXTERNAL BEAM EQUIPMENT and X-ray imaging
devices, attached or not directly attached to, but in the same RADIATION shielded area as, and
dedicated for use only with, the EXTERNAL BEAM EQUIPMENT.
This particular standard applies to X-ray based IGRT equipment used in-room for IGRT purposes.
This particular standard does not apply to standard CT scanners, which are not used for IGRT.
However if a CT scanner is used in-room with a linear (electron) accelerator (linac) for IGRT
then this particular standard applies.
When performing a HAZARD ANALYSIS, the MANUFACTURER should consider relevant diagnostic
standards. For example, the IMAGE DISPLAY DEVICE quality is specified in IEC documents in
regard to diagnostic use (e.g., IEC 62563-1:2009). However, since IGRT usage may or may does
not require necessarily have such high requirements, it is left to the MANUFACTURER to specify
what is required for use with their X-IGRT EQUIPMENT.
This document deals with the safety aspect of image acquisitions, image analysis, data transfer
and TREATMENT replanning or EBE/PATIENT repositioning.
This document deals with equipment for OFFLINE X-IGRT, ONLINE X-IGRT, and REAL-TIME X-IGRT.
X-IGRT EQUIPMENT is also related to the following current publications:
– IEC 60976, Medical electrical equipment – Medical electron accelerators – Functional
performance characteristics
– 8 – IEC 60601-2-68:2025 RLV © IEC 2025
– IEC TR 60977, Medical electrical equipment – Medical electron accelerators – Guidelines
for functional performance characteristics.
– IEC 60601-2-1
– IEC 60601-2-44
– IEC 60601-2-64
– IEC 62083
– IEC 61217
– IEC 62274
This particular standard may give rise to amendments to some of the above standards.
This document will focus on the safety aspects of the primary function of X-IGRT. It will not focus
on emerging technologies within the field so as to not hinder progress, yet it will define a safe
way of achieving X-IGRT.
MEDICAL ELECTRICAL EQUIPMENT –

Part 2-68: Particular requirements for the basic safety and essential
performance of X-ray-based image-guided radiotherapy equipment for use
with electron accelerators, light ion beam therapy equipment and
radionuclide beam therapy equipment

201.1 Scope, object and related standards
Clause 1 of the general standard 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 60601 applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of X-ray based
IMAGE-GUIDED RADIOTHERAPY equipment for use with EXTERNAL BEAM EQUIPMENT (EBE).
This document covers safety aspects of kilovoltage (kV) and megavoltage (MV) X-ray imaging
devices integrated in a known specified geometrical relationship with EBE for the purpose of
IGRT. It covers aspects of communication and relationships between the EXTERNAL BEAM
EQUIPMENT and X-ray imaging devices, attached or not directly attached to, but in the same
RADIATION shielded area as, and dedicated for use only with, the EXTERNAL BEAM EQUIPMENT.
This document deals with equipment for OFFLINE X-IGRT, ONLINE X-IGRT and REAL-TIME X-IGRT. It
covers procedures to reduce the risk of over-reliance on the X-IGRT EXTERNAL BEAM EBE SYSTEM
(X-IGRT EBS). For example, in the case of ONLINE X-IGRT, the MANUFACTURER will provide an
interactive interface for user interaction with the correction suggested by the system.
This document does not apply to CT SCANNERS, X-RAY EQUIPMENT for RADIOGRAPHY, and X-RAY
EQUIPMENT for RADIOSCOPY, that are not intended for use for IGRT.
Requirements that are being tested according to another standard can be identified by the
manufacturer. If these requirements are equivalent, retesting is not required, but instead
evidence can refer to the CT SCANNER, X-RAY EQUIPMENT for RADIOGRAPHY, or X-RAY for
RADIOSCOPY manufacturer's compliance statements or test reports.
If the X-IGRT EQUIPMENT is combined with an MEE, any requirement that is the same for the X-
IGRT EQUIPMENT and the MEE, such as a PATIENT POSITIONER, is not required to be tested twice,
but can be accepted as tested by the MEE.
This document applies to X-RAY EQUIPMENT for RADIOGRAPHY, RADIOSCOPY, and COMPUTER
TOMOGRAPHY used for IGRT.
If a clause or subclause is specifically intended to be applicable to X-IGRT EBE SYSTEMS, the
content of that clause or subclause will say so. Where that is not the case, the clause or
subclause applies only to X-IGRT EQUIPMENT.
___________
The general standard is IEC 60601-1:2005 + IEC 60601-1:2005/AMD1:2012, Medical electrical equipment – Part
1: General requirements for basic safety and essential performance

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This document, with the inclusion of TYPE TESTS and SITE TESTS, applies respectively to the
MANUFACTURER and some installation aspects of X-IGRT EBE SYSTEMS intended to be
• for NORMAL USE, operated under the authority of appropriately licensed or the RESPONSIBLE
ORGANIZATION by QUALIFIED PERSONS by OPERATORS having the required skills for a particular
medical application, for particular specified clinical purposes, e.g., STATIONARY
RADIOTHERAPY or MOVING BEAM RADIOTHERAPY,
• maintained in accordance with the recommendations given in the INSTRUCTIONS FOR USE,
and
• subject to regular quality assurance performance and calibration checks by a QUALIFIED
PERSON.
NOTE In this document, all references to installation refer to the installation in the RESPONSIBLE ORGANIZATION'S
premises.
201.1.2 Object
Replacement:
The object of this document is to establish particular BASIC SAFETY and ESSENTIAL PERFORMANCE
requirements for X-IGRT EQUIPMENT and X-IGRT EBE SYSTEMS.
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 60601-1-6 apply as modified in Clause 203 and Clause 206
respectively. IEC 60601-1-8, IEC 60601-1-9, IEC 60601-1-10 and IEC 60601-1-11 do not apply.
All other published collateral standards in the IEC 60601-1 series apply as published.
Collateral standards published after the date of publication of this standard shall only apply
subject to further amendment to this standard.
All other published collateral standards in the IEC 60601-1 series apply as published.
201.1.4 Particular standards
Replacement:
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 and collateral standards as appropriate for the particular
ME EQUIPMENT under consideration, and may add other BASIC SAFETY and 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.
For brevity, IEC 60601-1 is referred to in this particular standard as the general standard.
Collateral standards are referred to by their document number.

The numbering of clauses and subclauses of this document 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, 203.4 in this document addresses the content of Clause
4 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 is 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 3.139154,
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, for example 202
for IEC 60601-1-2, 203 for IEC 60601-1-3, etc.
The term "this document" is used to make reference to IEC 60601-1:2005,
IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020, any applicable collateral
standards and this document taken together.
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
NOTE Informative references are listed in the bibliography.

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Clause 2 of IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012, and
IEC 60601-1:2005/AMD2:2020 applies, except as follows:
Replacement:
IEC 60601-1-3:2008, Medical electrical equipment – Part 1-3: General requirements for basic
safety and essential performance – Collateral Standard: Radiation protection in diagnostic X-ray
equipment
IEC 60601-1-3:2008/AMD1:2013
IEC 60601-1-3:2008/AMD2:2021
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
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 60601-2-1:20092020, Medical electrical equipment – Part 2-1: Particular requirements for
the basic safety and essential performance of electron accelerators in the range 1 MeV to
50 MeV
IEC 60601-2-4:2010, Medical electrical equipment – Part 2-4: Particular requirements for the
basic safety and essential performance of cardiac defibrillators
IEC 60601-2-44:2012, Medical electrical equipment – Part 2-44: Particular requirements for
the basic safety and essential performance of X-ray equipment for computed tomography
IEC 60731:2011, Medical electrical equipment – Dosimeters with ionization chambers as used
in radiotherapy
IEC TR 60788:2004, Medical electrical equipment – Glossary of defined terms
IEC 60976:2007, Medical electrical equipment – Medical electron accelerators – Functional
performance characteristics
IEC 61000-4-3, Electromagnetic compatibility (EMC) – Part 4-3 : Testing and measurement
techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61217:2011, Radiotherapy equipment – Coordinates, movements and scales
IEC 61223-3-5:2004, Evaluation and routine testing in medical imaging departments – Part 3-
5: Acceptance tests – Imaging performance of computed tomography X-ray equipment
IEC 61262-7:1995, Medical electrical equipment – Characteristics of electro-optical X-ray
image intensifiers – Part 7: Determination of the modulation transfer function
IEC 62083:2009, Medical electrical equipment – Requirements for the safety of radiotherapy
treatment planning systems
IEC 62274:2005, Medical electrical equipment – Safety of radiotherapy record and verify
systems
IEC 62366:2007, Medical devices – Application of usability engineering to medical devices
IEC 62396-1:2012, Process management for avionics – Atmospheric radiation effects – Part 1:
Accommodation of atmospheric radiation effects via single event effects within avionics
electronic equipment
IEC 62563-1:2009, Medical electrical equipment – Medical image display systems – Part 1:
Evaluation methods
CISPR 11, Industrial, scientific and medical equipment – Radio-frequency disturbance
characteristics – Limits and methods of measurement
NOTE Informative references are listed in the bibliography beginning on page 58.
201.3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60601-2-1:2020,
IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012, and IEC 60601-1:2005/AMD2:2020, and
IEC TR 60788:2004 apply, except as follows:
NOTE An index of defined terms is found at the end of the document.
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
Additional terms and definitions:
201.3.201
COMPUTED TOMOGRAPHY DOSE INDEX 100
CTDI
integral of the DOSE PROFILE representative of a single axial scan along a line perpendicular to
the TOMOGRAPHIC PLANE divided by N × T according to the following:
for N × T less than or equal to 40 mm
+50mm Dy
( )
CTDI = dy
∫
−50mm
N×T
for N × T greater than 40 mm (all CT CONDITIONS OF OPERATION IGRT IMAGING PROTOCOL except
collimation are kept the same for these measurements)
+50 mm
CTDI
D (y) free air, N×T
Ref
=  dz ×
CTDI
∫
(N ×T) CTDI
Ref free air, Ref
−50 mm
+50mm Dy CTDI
( )
Ref free air,  N×T
CTDI dy×
∫
−50mm
N×T CTDI
( )
free air,  Ref
Ref
where
D(y) is the DOSE PROFILE representative of a single axial scan along a line
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
(PMMA) dosimetry PHANTOM (see 201.102.56.2);
=
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(N × T) is a specific N × T of 20 mm or the largest N x T available not greater
Ref
than 20 mm;
D (y) is the DOSE PROFILE representative of a single axial scan along a line
Ref
perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as
ABSORBED DOSE in air and is evaluated within a polymethylmethacrylate
(PMMA) dosimetry PHANTOM (see 201.102.56.2) for (N × T) ;
Ref
CTDI is the CTDI (201.3.202) for a specific value of N × T;
free air, N × T free air
CTDI is the CTDI (201.3.202) for (N × T) ;
free air, Ref free air Ref
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan
of the X-ray source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.
Note 1 to entry: The dose is reported as ABSORBED DOSE to air, but for practical purposes the evaluation of ABSORBED
DOSE to air within a PMMA dosimetry PHANTOM is well approximated by measurement of the AIR KERMA.
Note 2 to entry: This definition assumes that the DOSE PROFILE is centred on y = 0.
Note 3 to entry: A single axial scan is typically a 360° rotation of the X-ray source. For CBCT partial rotations are
still considered as a single axial scan.
Note 4 to entry: When the TOMOGRAPHIC SECTIONS overlap, e.g., in CT SCANNERS with a "y-flying FOCAL SPOT" or
with CBCT modes that merge multiple scans, the denominator of the integral needs to be replaced by the total nominal
width along y of overlapping tomographic sections. For example, if the percentage of overlap is 50 %, then the
denominator would be replaced with 0,5 x N x T.
Note 5 to entry: Typically, the y-axis is the axis of rotation (the y-axis corresponds to the z-axis in the DICOM
coordinate system).
Note 6 to entry: The CTDI is designed to include most of the scattered RADIATION.
Note 7 to entry: See IEC 60601-2-44:2009/AMD1:2012, Annex CC for more explanation.
Note 8 to entry: It is assumed for MV CBCT that an appropriate calibrated pencil chamber is used.
Note 9 to entry: The note to entry concerning the origin of the abbreviation CTDI APPLIES TO THE FRENCH TEXT ONLY.
[SOURCE: IEC 60601-2-44:2009/AMD1:2012, 201.3.203, modified – Notes 3, 4 and 5 to entry
have been extended, and Note 8 to entry added.]
201.3.202
COMPUTED TOMOGRAPHY DOSE INDEX FREE-IN-AIR
CTDI
free air
integral of the DOSE PROFILE representative of a single axial scan along a line through the
ISOCENTRE and perpendicular to the TOMOGRAPHIC PLANE divided by N × T according to the
following
+L/2
Dy( )
CTDI = dy
free air
∫
−L/2
N×T
where
D(y) is the DOSE PROFILE representative of a single axial scan along a line through ISOCENTRE
and perpendicular to the TOMOGRAPHIC PLANE, where dose is reported as ABSORBED DOSE
in air and is evaluated free-in-air in the absence of a PHANTOM and the PATIENT SUPPORT;
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
L is at least (N × T) +40 mm, but not less than 100 mm.

Note 1 to entry: This definition assumes that the DOSE PROFILE is centred on y = 0. The y axis corresponds to the z
axis in the DICOM coordinate system.
Note 2 to entry: When the TOMOGRAPHIC SECTIONS overlap, e.g., in CT SCANNERS with a "y-flying FOCAL SPOT" or
with CBCT modes that merges multiple scans, the denominator of the integral needs to be replaced by the total
nominal width along y of overlapping tomographic sections. For example, if the percentage of overlap is 50 %, then
the denominator would be replaced by 0,5 × N × T.
Note 3 to entry: Typically, a RADIATION DETECTOR of length L or longer is used. Annex DD provides an example for
alternate measurements.
Note 4 to entry: For CBCT, the imaging is not slice based and N × T is the scan length along a line perpendicular to
the TOMOGRAPHIC PLANE with the NOMINAL collimation.
Note 5 to entry: It is assumed for MV CBCT that an appropriate calibrated pencil chamber or ion chamber, and a
build-up cap is used.
[SOURCE: IEC 60601-2-44:2009/AMD1:2012, 201.3.215, modified – Note 1 and 2 to entry have
been extended and Notes 4 and 5 to entry added.]
201.3.203
CONE BEAM COMPUTED TOMOGRAPHY
CBCT
computed tomography performed using a cone beam of X-RADIATION
201.3.204
CONTRAST TO NOISE RATIO
CNR
physical quantity describing the ability to distinguish between various contrast objects of a
digital image and the inherent noise within the image, defined as the difference of mean pixel
values of the contrast objects and image background, and divided by the standard deviation of
the image background pixel value
S – S
AB
C =
Note 1 to entry:
σ
S and S are signal intensities for the signal producing structures A and B in the region of interest and is the
σ
A B 0
standard deviation of the image noise. The MANUFACTURER specifies the structures defining A and B.
Note 2 to entry: The note to entry concerning the origin of the abbreviation CNR APPLIES TO THE FRENCH TEXT ONLY.
[SOURCE: IEC 61223-3-2:2007, 3.8, modified – Two notes to entry have been added.]
201.3.205
DOSE-LENGTH PRODUCT
DLP
index characterizing the product of the CTDI and the total length scanned
vol
a) For axial scanning
DLP = CTDI × ∆d × n
vol
where
∆d is the PATIENT SUPPORT travel in y-direction between consecutive scans;
n is the number of scans in the series.
b) For helical scanning
DLP = CTDI ×L
vol
where
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L is the table travel during the entire LOADING, adjusted for dynamic collimation modes
where applicable.
Note 1 to entry: L might be longer than the programmed scan length.
Note 2 to entry: The time weighted average of CTDI is to be used if CTDI is variable.
vol vol
Note 3 to entry: A way for obtaining L could be to use the FWHM along a line perpendicular to the TOMOGRAPHIC
PLANE at isocentre of the free-in-air DOSE PROFILE for the entire scan. In the absence of dynamic collimation this
is approximately equivalent to table travel during the entire LOADING.
c) For scanning without movement of the PATIENT SUPPORT
DLP = CTDI ×N×T
vol
where
N is the number of TOMOGRAPHIC SECTIONS PRODUCED in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS.
Note 4 to entry: For CBCT, usually only c) is applicable where N × T is the scan length along a line perpendicular
to the TOMOGRAPHIC PLANE with the NOMINAL collimation.
Note 5 to entry: Typically, the y-axis is the axis of rotation. The y axis corresponds to the z axis in the DICOM
coordinate system.
d) For axial scanning without gaps and helical scanning, both involving back-and-forth PATIENT
SUPPORT movement between two positions (shuttle mode)
DLP = CTDI × N×T + R
(( ) )
vol
where
N is the number of TOMOGRAPHIC SECTIONS produced in a single axial scan of the X-ray
source;
T is the NOMINAL TOMOGRAPHIC SECTION THICKNESS;
R is the distance between the two positions.
Note 6 to entry: The note to entry concerning the origin of the abbreviation DLP APPLIES TO THE FRENCH TEXT
ONLY.
[SOURCE: IEC 60601-2-44:2009 and IEC 60601-2-44:2009/AMD1:2012, 201.3.214, modified –
Notes 4 and 5 to entry have been added.]
201.3.206
DOSE PROFILE
representation of the dose as a function of position along a line
[SOURCE: IEC 60601-2-44:2009/AMD1:2012, 201.3.205]
201.3.207
EQUIPMENT REFERENCE POINT
ERP
point in space used for referencing dimensions and positions of equipment and performing
dosimetry measurements
201.3.207208
EXTERNAL BEAM EQUIPMENT
EBE
external RADIATION EQUIPMENT utilizing ELECTRON ACCELERATORS, light ion beam medical
electrical equipment or RADIONUCLIDE BEAM THERAPY EQUIPMENT

Note 1 to entry: The note to entry concerning the origin of the abbreviation EBE APPLIES TO THE FRENCH TEXT ONLY.
201.3.208209
IGRT EQUIPMENT
ME EQUIPMENT that provides IGRT functionality
201.3.210
* IGRT LATENCY
time from initiation of image acquisition to output signal by X-IGRT EQUIPMENT to the EBE
Note 1 to entry: It is expected that the EBE can also state its latency time from receiving the signal to providing the
correction.
Note 2 to entry: The IGRT LATENCY includes the hardware and software latencies.
Note 3 to entry: Network transfer times vary from one installation to another as there are too many factors involved
that are supplied by the RESPONSIBLE ORGANIZATION. Network transfer latency therefore is not considered as part of
the IGRT LATENCY time.
201.3.209211
IMAGE-GUIDED RADIOTHERAPY
IGRT
radiotherapy process by which the location of a radiotherapy beam relative to the intended
TARGET VOLUME within a patient's anatomy is determined by imaging of the TARGET VOLUME and
surrounding anatomical structures at the time of TREATMENT, so as to enable any necessary
positional corrections to the intended relative location of beam to TARGET VOLUME
Note 1 to entry: The note to entry concerning the origin of the abbreviation IGRT APPLIES TO THE FRENCH TEXT ONLY.
Note 1 to entry: The time period of "at the time of TREATMENT" is specified in the definitions of OFFLINE IGRT, ONLINE
IGRT and REAL-TIME IGRT.
[SOURCE: IEC 60976:2007, 3.8, modified ─ Addition of Note 1 to entry.]
201.3.212
IMAGING PROTOCOL
set of parameters necessary to perform imaging
Note 1 to entry: The following modes are examples of different types of imaging: radiography, radioscopy, helical,
axial, axial series, scanning without movement of the PATIENT P
...