IEC 60601-1: Parents, Collaterals & Particulars
This column will appear occasionally in Sound Waves and will discuss topics concerning IEC (International Electrotechnical Commission), ISO (International Standards Organization), and international standards and how they affect the ultrasound community.
Within IEC the major safety standard for medical electrical equipment is
IEC 60601-1: Medical electrical equipment - Part 1: General requirements for safety
This standard establishes general safety requirements for all aspects of medical devices from light boxes to beds to high-end diagnostic equipment like ultrasound or magnetic resonance (MR). Included are test requirements, documentation, protection from electrical hazards, protection from mechanical hazards, protection against excessive or unwanted radiation, protection against temperature, fire prevention, ingress of liquids, disinfection, biocompatibility etc. IEC 60601-1 is presently at edition 2.2 and was last published in 1997. This standard is presently in the final stages of a major overhaul to edition 3 due out in mid-2005. As the release date gets closer, a separate column will discuss the key differences of this future revision.
IEC 60601-1 is referred to as a "parent" standard in IEC parlance. It is the "default" set of requirements for all medical electrical equipment. There are 2 types of "sibling" standards related to the 60601-2 parent:
- The Collateral Standard. The collateral standard contains requirements that are an addition to the parent. Collaterals are referred to as "dash-one" standards and are numbered IEC 60601-1-x. Collateral standards cover topics applicable to all medical electrical equipment-just like the parent standard. They may be published separately due to the unique nature of the topic, like EMC, or may simply be an issue that was not considered or not complete when the parent was last revised. At present there are 8 collaterals including medical systems, programmable systems, electromagnetic compatibility, alarms etc. As the parent is revised, existing collaterals are occasionally absorbed into the parent. The upcoming third edition of 60601-1 absorbs 2 of the existing collateral standards.
- The Particular Standard: The particular standard contains requirements that are exceptions to both the parent and the collateral standards. Particular standards are written for specific types of devices such as X-ray, MR, computed tomography (CT) and the like. Particulars are referred to as "dash-two" standards and are numbered IEC 60601-2-x. At present, there are 54 particular standards. The particular standard for the safety of ultrasonic medical diagnostic and monitoring equipment is IEC 60601-2-37. Particular standards identify changes to the parent standards and any applicable collateral standard, which are unique to that particular technology. In the case of ultrasound, the particular standard addresses such items as the feedback system provided to the operator (MI & TI display), unique EMC concerns caused by the transducer, and transducer surface temperature.
"Edition" numbers are 2 digits - the first is the present revision number of the standard and the second is the last amendment number. Amendments are first published separately and then may be combined into a single document if a new edition is several years out. Corrigenda are also published if needed to fix a particularly egregious typographical or editorial error.
The following 60601 standards are of interest to the design, use, and maintenance of diagnostic ultrasound imaging equipment:
IEC 60601-1 ed 2.2: Medical electrical equipment- Part 1: General requirements for safety
IEC 60601-1-1 ed 2.0: Medical electrical equipment- Part 1: General requirements for safety-1. Collateral standard: Safety requirements for medical electrical systems
IEC 60601-1-2 ed 1.0: Medical electrical equipment- Part 1: General requirements for safety-2. Collateral Standard: Electromagnetic compatibility - Requirements and tests
IEC 60601-1-4 ed 1.1: Medical electrical equipment-Part 1: General requirements for safety-4. Collateral standard: Programmable electrical medical systems
IEC 60601-2-37 ed 1.1: Medical electrical equipment- Part 2-37: Particular requirements for the safety of ultrasonic medical diagnostic and monitoring equipment
Further questions on this topic may be directed to the author at iec_iso@aium.org.
John Abbott, PhD,
IEC Liaison for the AIUM