YY 9706.268-2022 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 (English)
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
YY 9706.268-2022 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 applies, except as follows:
201.1.1 Scope
Replacement:
This document 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 in a known geometrical relationship with EBE for the purpose of image-guided radiotherapy (IGRT). It covers aspects of communication and relationships between the EBE 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 EBE.
This document deals with equipment for real-time X-IGRT, online X-IGRT and offline X-IGRT. It covers procedures to reduce the risk of over-reliance on the X-IGRT external beam system (X-IGRT EBS). For example, the manufacturer will provide an interactive interface for user interaction with the correction suggested by the system.
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. If 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 appropriately licensed or 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;
subject to regular quality assurance performance and calibration checks by a qualified person.
Note: In this document, all references to installation refer to 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 the general standard and Clause 201.2 of this document.
GB 9706.103 and YY/T 9706.106 apply as modified in Clause 203 and Clause 206 respectively. YY 9706.108, IEC 60601-1-9, YY/T 9706.110 and YY 9706.111 do not apply. All other published collateral standards in the 9706 series apply as published.
Collateral standards published after the date of publication of this document shall only apply subject to further amendment to this document.
201.1.4 Particular standards
Replacement:
In the 9706 series, particular standards may modify, replace or delete requirements contained in the general standard 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 the general standard.
For brevity, GB 9706.1 is referred to in this document 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 the general standard with the prefix "201" (e.g. 201.1 in this document addresses the content of Clause 1 of the general standard) or applicable collateral standard with the prefix "20×", where × 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 YY 9706.102 collateral standard, 203.4 in this document addresses the content of Clause 4 of the GB 9706.103 collateral standard, etc.). The changes to the text of the general standard are specified by the use of the following words:
"Replacement" means that the clause or subclause of the general standard 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 the general standard or applicable collateral standard.
"Amendment" means that the clause or subclause of the general standard or applicable collateral standard is amended as indicated by the text of this document.
Subclauses, figures or tables which are additional to those of the general standard are numbered starting from 201.101. However, due to the fact that definitions in the general standard are numbered 3.1 through 3.147, 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 20×, where “×” is the number of the collateral standard, e.g. 202 for YY 9706.102, 203 for GB 9706.103, etc.
The term "this standard" is used to make reference to the general standard, any applicable collateral standard and this document taken together.
Where there is no corresponding clause or subclause in this document, the clause or subclause of the general standard or applicable collateral standard, although not relevant, applies without modification; where it is intended that any part of the general standard or applicable collateral standard, although relevant, is not to be applied, a statement to that effect is given in this document.
201.2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 the general standard applies, except as follows:
Amendment:
GB 9706.103-2020 Medical electrical equipment - Part 1-3: General requirements for basic safety and essential performance - Collateral standard: Radiation protection in diagnostic X-ray equipment (IEC 60601-1-3:2013, MOD)
YY/T 9706.106-2021 Medical electrical equipment - Part 1-6: General requirements for basic safety and essential performance - Collateral standard: Usability (IEC 60601-1-6:2013, MOD)
Addition:
GB 9706.1-2020 Medical electrical equipment - Part 1: General requirements for basic safety and essential performance (IEC 60601-1:2012, MOD)
GB 9706.201-2020 Medical electrical equipment - Part 2-1: Particular requirements for the basic safety and essential performance of electron accelerators in the range 1MeV to 50MeV (IEC 60601-2-1:2014, MOD)
GB 9706.244-2020 Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography (IEC 60601-2-44:2016, MOD)
GB/T 18987-2015 Radiotherapy equipment - Coordinates, movements and scales (IEC 61217:2008, IDT)
YY/T 0910.1-2013 Medical electrical equipment - Medical image display systems - Part 1: Evaluation methods (IEC 62563-1:2009, IDT)
YY 9706.102-2021 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic compatibility - Requirements and tests
ISO 12052 Health informatics - Digital imaging and communication in medicine (DICOM) including workflow and data management
IEC/TR 60788:2004 Medical electrical equipment - Glossary of defined terms
201.3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB 9706.201, GB 9706.1-2020 and IEC/TR 60788:2004 and the following apply.
Addition:
201.3.201
computed tomography dose index 100
CTDI100
integral of the dose profile representative of a single axial scan along a line perpendicular to the tomographic plane divided by N×T (the number of tomographic sections × the nominal tomographic section thickness) according to the following:
for N×T less than or equal to 40mm:
for N×T greater than 40mm (all CT conditions of operation except collimation are kept the same for these measurements):
where,
D(y)——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 201.102.5.2);
(N×T)Ref——a specific N×T of 20mm or the largest N×T available not greater than 20mm;
DRef(y)——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 201.102.5.2) for (N×T)Ref;
CTDIfree air,N×T——the CTDIfree air (201.3.202) for a specific value of N×T;
CTDIfree air,Ref——the CTDIfree air (201.3.202) for (N×T)Ref;
N——the number of tomographic sections produced in a single axial scan of the X-ray source;
T——the nominal tomographic section thickness.
Note 1: 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: This definition assumes that the dose profile is centered on y=0.
Note 3: 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: 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 by 0.5×N×T.
Note 5: Typically the y-axis is the axis of rotation (the y-axis corresponds to the z-axis in the DICOM coordinate system.)
Note 6: The CTDI100 is designed to include most of the scattered radiation.
Note 7: See GB 9706.244-2020, Annex CC for more explanation.
Note 8: It is assumed for CBCT that an appropriate calibrated pencil chamber is used.
[Source: GB 9706.244-2020, 201.3.203, modified]
201.3.202
computed tomography dose index free-in-air
CTDIfree air
integral of the dose profile representative of a single axial scan along a line through isocenter and perpendicular to the tomographic plane divided by N×T (the number of tomographic sections × the nominal tomographic section thickness) according to the following:
where,
D(y)——the dose profile representative of a single axial scan along a line through isocenter 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——the number of tomographic sections produced in a single axial scan of the X-ray source;
T——the nominal tomographic section thickness;
L——at least (N×T)+40mm, but not less than 100mm.
Note 1: This definition assumes that the dose profile is centered on y=0. The y-axis corresponds to the z-axis in the DICOM coordinate system.
Note 2: 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 by 0.5×N×T.
Note 3: Typically a radiation detector of length L or longer is used. Annex DD provides an example for alternate measurements.
Note 4: 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: It is assumed for MV CBCT that an appropriate calibrated pencil chamber or ionization chamber, and a build-up cap is used.
[Source: GB 9706.244-2020, 201.3.215, modified]
201.3.203
cone beam computed tomography; CBCT
computed tomography performed using a cone beam of X-radiation
Contents
Foreword i
Introduction iii
201.1 Scope, object and related standards
201.2 Normative references
201.3 Terms and definitions
201.4 General requirements
201.5 General requirements for testing ME equipment
201.6 Classification of ME equipment and ME systems
201.7 ME equipment identification, marking and documents
201.8 Protection against electrical hazards from ME equipment
201.9 Protection against mechanical hazards of ME equipment and ME systems
201.10 Protection against unwanted and excessive radiation hazards
201.11 Protection against excessive temperatures and other hazards
201.12 Accuracy of controls and instruments and protection against hazardous outputs
201.13 Hazardous situations and fault conditions for ME equipment
201.14 Programmable electrical medical systems (PEMS)
201.15 Construction of ME equipment
201.16 ME systems
201.17 Electromagnetic compatibility of ME equipment and ME systems
201.101 Reference data for X-IGRT
201.102 IGRT imaging
201.103 IGRT analysis and correction
203 Radiation protection in diagnostic X-ray equipment
203.4 General requirements
203.6 Radiation management
203.8 Limitation of the extent of the X-ray beam and relationship between X-ray field and image reception area
203.10 Attenuation of the X-ray beam between the patient and the X-ray image receptor
203.11 Protection against residual radiation
203.13 Protection against stray radiation
206 Usability
Annexes
Annex B (Informative) Sequence of testing
Annex I (Informative) ME systems aspects
Annex AA (Informative) Particular guidance and rationale
Annex BB (Informative) Measuring CTDIfree air
Bibliography
Standard
YY 9706.268-2022 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 (English)
Standard No.
YY 9706.268-2022
Status
valid
Language
English
File Format
PDF
Word Count
21000 words
Translation Price(USD)
630.0
Implemented on
2025-6-1
Delivery
via email in 1 business day
Detail of YY 9706.268-2022
Standard No.
YY 9706.268-2022
English Name
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
YY 9706.268-2022 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 applies, except as follows:
201.1.1 Scope
Replacement:
This document 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 in a known geometrical relationship with EBE for the purpose of image-guided radiotherapy (IGRT). It covers aspects of communication and relationships between the EBE 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 EBE.
This document deals with equipment for real-time X-IGRT, online X-IGRT and offline X-IGRT. It covers procedures to reduce the risk of over-reliance on the X-IGRT external beam system (X-IGRT EBS). For example, the manufacturer will provide an interactive interface for user interaction with the correction suggested by the system.
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. If 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 appropriately licensed or 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;
subject to regular quality assurance performance and calibration checks by a qualified person.
Note: In this document, all references to installation refer to 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 the general standard and Clause 201.2 of this document.
GB 9706.103 and YY/T 9706.106 apply as modified in Clause 203 and Clause 206 respectively. YY 9706.108, IEC 60601-1-9, YY/T 9706.110 and YY 9706.111 do not apply. All other published collateral standards in the 9706 series apply as published.
Collateral standards published after the date of publication of this document shall only apply subject to further amendment to this document.
201.1.4 Particular standards
Replacement:
In the 9706 series, particular standards may modify, replace or delete requirements contained in the general standard 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 the general standard.
For brevity, GB 9706.1 is referred to in this document 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 the general standard with the prefix "201" (e.g. 201.1 in this document addresses the content of Clause 1 of the general standard) or applicable collateral standard with the prefix "20×", where × 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 YY 9706.102 collateral standard, 203.4 in this document addresses the content of Clause 4 of the GB 9706.103 collateral standard, etc.). The changes to the text of the general standard are specified by the use of the following words:
"Replacement" means that the clause or subclause of the general standard 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 the general standard or applicable collateral standard.
"Amendment" means that the clause or subclause of the general standard or applicable collateral standard is amended as indicated by the text of this document.
Subclauses, figures or tables which are additional to those of the general standard are numbered starting from 201.101. However, due to the fact that definitions in the general standard are numbered 3.1 through 3.147, 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 20×, where “×” is the number of the collateral standard, e.g. 202 for YY 9706.102, 203 for GB 9706.103, etc.
The term "this standard" is used to make reference to the general standard, any applicable collateral standard and this document taken together.
Where there is no corresponding clause or subclause in this document, the clause or subclause of the general standard or applicable collateral standard, although not relevant, applies without modification; where it is intended that any part of the general standard or applicable collateral standard, although relevant, is not to be applied, a statement to that effect is given in this document.
201.2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 the general standard applies, except as follows:
Amendment:
GB 9706.103-2020 Medical electrical equipment - Part 1-3: General requirements for basic safety and essential performance - Collateral standard: Radiation protection in diagnostic X-ray equipment (IEC 60601-1-3:2013, MOD)
YY/T 9706.106-2021 Medical electrical equipment - Part 1-6: General requirements for basic safety and essential performance - Collateral standard: Usability (IEC 60601-1-6:2013, MOD)
Addition:
GB 9706.1-2020 Medical electrical equipment - Part 1: General requirements for basic safety and essential performance (IEC 60601-1:2012, MOD)
GB 9706.201-2020 Medical electrical equipment - Part 2-1: Particular requirements for the basic safety and essential performance of electron accelerators in the range 1MeV to 50MeV (IEC 60601-2-1:2014, MOD)
GB 9706.244-2020 Medical electrical equipment - Part 2-44: Particular requirements for the basic safety and essential performance of X-ray equipment for computed tomography (IEC 60601-2-44:2016, MOD)
GB/T 18987-2015 Radiotherapy equipment - Coordinates, movements and scales (IEC 61217:2008, IDT)
YY/T 0910.1-2013 Medical electrical equipment - Medical image display systems - Part 1: Evaluation methods (IEC 62563-1:2009, IDT)
YY 9706.102-2021 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic compatibility - Requirements and tests
ISO 12052 Health informatics - Digital imaging and communication in medicine (DICOM) including workflow and data management
IEC/TR 60788:2004 Medical electrical equipment - Glossary of defined terms
201.3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB 9706.201, GB 9706.1-2020 and IEC/TR 60788:2004 and the following apply.
Addition:
201.3.201
computed tomography dose index 100
CTDI100
integral of the dose profile representative of a single axial scan along a line perpendicular to the tomographic plane divided by N×T (the number of tomographic sections × the nominal tomographic section thickness) according to the following:
for N×T less than or equal to 40mm:
for N×T greater than 40mm (all CT conditions of operation except collimation are kept the same for these measurements):
where,
D(y)——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 201.102.5.2);
(N×T)Ref——a specific N×T of 20mm or the largest N×T available not greater than 20mm;
DRef(y)——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 201.102.5.2) for (N×T)Ref;
CTDIfree air,N×T——the CTDIfree air (201.3.202) for a specific value of N×T;
CTDIfree air,Ref——the CTDIfree air (201.3.202) for (N×T)Ref;
N——the number of tomographic sections produced in a single axial scan of the X-ray source;
T——the nominal tomographic section thickness.
Note 1: 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: This definition assumes that the dose profile is centered on y=0.
Note 3: 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: 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 by 0.5×N×T.
Note 5: Typically the y-axis is the axis of rotation (the y-axis corresponds to the z-axis in the DICOM coordinate system.)
Note 6: The CTDI100 is designed to include most of the scattered radiation.
Note 7: See GB 9706.244-2020, Annex CC for more explanation.
Note 8: It is assumed for CBCT that an appropriate calibrated pencil chamber is used.
[Source: GB 9706.244-2020, 201.3.203, modified]
201.3.202
computed tomography dose index free-in-air
CTDIfree air
integral of the dose profile representative of a single axial scan along a line through isocenter and perpendicular to the tomographic plane divided by N×T (the number of tomographic sections × the nominal tomographic section thickness) according to the following:
where,
D(y)——the dose profile representative of a single axial scan along a line through isocenter 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——the number of tomographic sections produced in a single axial scan of the X-ray source;
T——the nominal tomographic section thickness;
L——at least (N×T)+40mm, but not less than 100mm.
Note 1: This definition assumes that the dose profile is centered on y=0. The y-axis corresponds to the z-axis in the DICOM coordinate system.
Note 2: 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 by 0.5×N×T.
Note 3: Typically a radiation detector of length L or longer is used. Annex DD provides an example for alternate measurements.
Note 4: 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: It is assumed for MV CBCT that an appropriate calibrated pencil chamber or ionization chamber, and a build-up cap is used.
[Source: GB 9706.244-2020, 201.3.215, modified]
201.3.203
cone beam computed tomography; CBCT
computed tomography performed using a cone beam of X-radiation
Contents of YY 9706.268-2022
Contents
Foreword i
Introduction iii
201.1 Scope, object and related standards
201.2 Normative references
201.3 Terms and definitions
201.4 General requirements
201.5 General requirements for testing ME equipment
201.6 Classification of ME equipment and ME systems
201.7 ME equipment identification, marking and documents
201.8 Protection against electrical hazards from ME equipment
201.9 Protection against mechanical hazards of ME equipment and ME systems
201.10 Protection against unwanted and excessive radiation hazards
201.11 Protection against excessive temperatures and other hazards
201.12 Accuracy of controls and instruments and protection against hazardous outputs
201.13 Hazardous situations and fault conditions for ME equipment
201.14 Programmable electrical medical systems (PEMS)
201.15 Construction of ME equipment
201.16 ME systems
201.17 Electromagnetic compatibility of ME equipment and ME systems
201.101 Reference data for X-IGRT
201.102 IGRT imaging
201.103 IGRT analysis and correction
203 Radiation protection in diagnostic X-ray equipment
203.4 General requirements
203.6 Radiation management
203.8 Limitation of the extent of the X-ray beam and relationship between X-ray field and image reception area
203.10 Attenuation of the X-ray beam between the patient and the X-ray image receptor
203.11 Protection against residual radiation
203.13 Protection against stray radiation
206 Usability
Annexes
Annex B (Informative) Sequence of testing
Annex I (Informative) ME systems aspects
Annex AA (Informative) Particular guidance and rationale
Annex BB (Informative) Measuring CTDIfree air
Bibliography
