Standards Development

Scope

Clause 1 of the general standard[1]) applies, except as follows:Replacement:This International Standard applies to the basic safety and essential performance of CT scanners, hereafter also referred to as me equipment.If a clause or subclause is specifically intended to be applicable to me equipment only, or to me systems only, the title and content of that clause or subclause will say so. If that is not the case, the clause or subclause applies both to me equipment and to me systems, as relevant.NOTE 1 See also 4.2 of the general standard.The scope of this document is limited to CT scanners intended to be used for head and/or body imaging characterised by an enclosure of the X-ray source(s) and imaging detector(s) in a common protective cover in the shape of a toroid. It includes safety requirements for the X-ray generators used in CT scanners, including those where high-voltage generators are integrated with an X-ray tube assembly.NOTE 2 This standard does not intend to address interventional systems as described in IEC 60601-2-43 and cone-beam CT scanners integrated into a radiotherapy systems as described in IEC 60601-2-68 and dental cone-beam CT scanners as described in IEC 60601-2-63.NOTE 3 Requirements for X-ray generators and for associated equipment, which were previously specified in IEC 60601-2-7 and IEC 60601-2-32, have been included in either IEC 60601-1:2005 (Ed3) or previous edition of IEC 60601-2-44. Therefore IEC 60601-2-7 and IEC 60601-2-32 are not part of the 4th edition scheme for computed tomography.NOTE 4 The body includes cardiac, extremities, neck, etc.The scope of this International Standard excludes radiotherapy simulators and systems where the image is created by a source other than an X-ray tube.Replacement:The object of this particular standard is to establish particular basic safety and essential performance requirements for CT scanners as defined in 201.3.201, to ensure safety, and to specify methods for demonstrating compliance with those requirements, for CT scanners.NOTE 1 Requirements for reproducibility, linearity, constancy and accuracy are given because of their relationship to the quality and quantity of the ionizing radiation produced and are confined to those considered necessary for safety.NOTE 2 Both the levels for compliance and the tests prescribed to determine compliance reflect the fact that the safety of high‑voltage generators is not sensitive to small differences in levels of performance. The combinations of loading factors specified for the tests are therefore limited in number but chosen from experience as being appropriate in most cases. It is considered important to standardize the choice of combinations of loading factors so that comparison can be made between tests performed in different places on different occasions. However, combinations other than those specified could be of equal technical validity.NOTE 3 The safety philosophy on which this standard is based is described in the introduction to the general standard and in IEC TR 60513.NOTE 4 Concerning radiological protection, it is assumed that manufacturers and responsibile organizations accept the general principles of justification, optimisation, and application of dose limits of the International Commission on Radiological Protection as stated in ICRP 103, 2007, paragraph 203, [12][2]) namely:(a) “The principle of justification: Any decision that alters the radiation exposure situation should do more good than harm.”(b) “The principle of optimisation of protection: The likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors.”(c) “The principle of application of dose limits: The total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed the appropriate limits recommended by the Commission.”(d) "Application of dose limits for the patient dose might be to the patient’s detriment. Therefore, dose limits should not be applied to medical exposures. However, considerations should be given to the use of dose constraints or investigation levels for some common diagnostic procedures. This concept, now renamed as diagnostic reference levels, has been introduced in a large number of countries."NOTE 5 It is recognized that many of the judgements necessary to follow the ICRP general principles have to be made by the responsible organizations and not by the manufacturer of the me equipment.Addition:This particular standard refers to those applicable collateral standards that are listed in Clause 2 of the general standard and Clause 201.2 of this particular standard.A requirement of a particular standard takes priority over applicable collateral standards. IEC 60601-1-2:2014+AMD1:2020 and IEC 60601-1-3:2008+AMD1:2013+AMD2:2021 apply as modified in Clauses 202 and 203. IEC 60601-1-8, IEC 60601-1-9, IEC 60601-1-10[3]), IEC 60601-1-11[4]) and IEC 60601-1-12[5]) do not apply.All other published collateral standards in the IEC 60601-1 series apply as published.If a CT-SCANNER is intended for use in EMERGENCY MEDICAL SERVICES ENVIRONMENT, this situation shall be taken into account in the RISK MANAGEMENT FILE.If an ECG monitor is integrated into the ct system for the sole purposes of providing triggers for cardiac and vascular examinations and other examinations affected by cardiac motion, the ECG monitor does not need to conform to IEC 60601-2-27.For collateral standards published after this particular standard, manufacturers need to determine the applicability in accordance with the risk management process. Replacement:In the IEC 60601 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, IEC 60601-1 is referred to in this particular standard as the general standard. Collateral standards are referred to by their document numbers.The numbering of clauses and subclauses of this particular standard corresponds to that of the general standard with the prefix “201” (e.g. 201.1 in this standard addresses the content of Clause 1 of the general standard) 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 particular standard addresses the content of Clause 4 of the 60601-1-2 collateral standard, 203.4 in this particular standard addresses the content of Clause 4 of the 60601-1-3 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 particular standard."Addition" means that the text of this particular standard 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 particular standard.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 3.154, additional definitions in this standard 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.The term "this standard" is used to make reference to the general standard, any applicable collateral standards and this particular standard taken together.Where there is no corresponding section, clause or subclause in this particular standard, the section, clause or subclause of the general standard or applicable collateral standard, although possibly not relevant, applies without modification; where it is intended that any parts of the general standard or applicable collateral standard, although possibly relevant, is not to be applied, a statement to that effect is given in this particular standard.