International Standards and Conformity Assessment for all electrical, electronic and related technologies

May 2013

 

Dr Robot needs standards too!

With more robots used in medical care, International Standards are vital for safety

Gurvinder S. Virk, Convenor IEC SC 62A/JWG 9

Robotic systems have been around in industry for more than 50 years. Their introduction to the medical and healthcare environment around the world is much more recent and carries the obvious need to ensure safe usage for patients and medical staff alike. A 2011 created IEC/ISO Joint Working Group prepares International Standards for Medical electrical equipment and systems using robotic technology.

Necessary cooperation

New applications for robots are emerging in the medical sector. Many medical device regulatory regimes, such as the European Commission’s Medical Device Directive, classify these robots as medical equipment or medical devices.

 

The SCs (Subcommittees) and WGs (Working Groups) of IEC TC 62: Electrical equipment in medical practice, have been responsible for carrying out the bulk of the medical equipment standardization work required to produce the IEC 60601 family of standards. These cover the safety requirements for ME (medical electrical) equipment and MES (medical electrical systems) in current use.

 

The introduction of robots to manufacturing in the early 1960s carried with it the need, satisfied by ISO (International Organization for Standardization), for development of a number of standards. They included standards for robotic vocabulary and characteristics, safety requirements, performance assessment and interfaces. The standards allow for industrial robot regulation as well as for the safe operation of robots as machines that are housed in real or virtual cages to separate them from humans and so prevent harm occurring.

 

Recently, personal care robots have been introduced. In providing a range of services to people, many of their designated tasks involve close robot-human interaction. This has led to their classification and regulation as machinery and relevant standards are being prepared by ISO TC (Technical Committee) 184/SC (Subcommittee) 2: Robots and robotic devices.

No need to reinvent the wheel

Discussions centring on medical robot standardization issues took place between ISO TC 184/SC 2 and IEC SC 62A: Common aspects of electrical equipment used in medical practice, and demonstrated that both had a valuable role to play in the work. Combining the existing industrial and service robot expertise of ISO TC 184/SC 2 with the medical electrical equipment expertise of IEC TC 62 enabled the key issues to be investigated. This also allowed the medical robot standards needed to fit into the IEC 60601 family to be produced without having to start from scratch and "reinvent the wheel".

 

It was decided that the first step should be to develop a horizontal medical robot standard, making the link between robots and medical electrical equipment; once this had been done, the work could be followed with a variety of vertical standards for different types of medical robots. In April 2011, IEC TC SC 62A and ISO TC 184/SC 2 set up JWG (Joint Working Group) 9: Medical electrical equipment and systems using robotic technology.

 

JWG 9’s remit is to "develop general requirements and guidance related to the safety of medical electrical equipment and systems that utilize robotic technology. The work encompasses medical applications (including aids for the disabled) covering invasive and non-invasive procedures such as surgery, rehabilitation therapy, imaging and other robots for medical diagnosis and treatment". The group started with 33 experts from 11 countries, it has now 57 experts from 16 countries.

Substantial work so far

JWG 9 brings together experts in the fields of machine safety and medical device safety. The group has been investigating the fundamental difference between ME equipment as defined in IEC 60601-1, Medical electrical equipment, and the emerging medical robots so as to find a common basis for the standardization work on medical robots.

 

According to its definition, ME equipment is intended for use in the diagnosis, treatment, or monitoring of a patient, or to compensate for or alleviate the effects of disease, injury or disability. As medical robots have the same intended functions, the differences between the two categories need identifying so as to ascertain specifications for the new standardization work. JWG 9 has investigated the issues and has concluded that the key difference is the "degree of autonomy". The expression is found in the ISO 8373 robot vocabulary standard which defines the term "robot" as an "actuated mechanism programmable in two or more axes with a degree of autonomy, moving within its environment, to perform intended tasks". The ISO standard further defines autonomy as the "ability to perform intended tasks based on current state and sensing, without human intervention". Although JWG 9 has recognized that these definitions might need some refinement for medical applications, it is clear that use of the term "medical robot" automatically includes the possibility of autonomous capabilities for ME equipment. This point is not fully addressed within the IEC 60601 family of documents.

The road ahead

ME equipment manufacturers have begun adopting autonomous functionalities into MES, as do the IEC 60601 standards. Some of the results are enhanced outcomes for medical procedures (such as shorter treatment), improved economic value and improved consistency and reliability of MES.

 

Autonomy in ME equipment and MES however, also introduces additional hazards that need to be addressed more comprehensively than is currently the case with the IEC 60601 documents. This is why a horizontal type standard is being developed, with the title "Medical electrical equipment and medical electrical systems employing a degree of autonomy" rather than restricting attention to "medical robots" alone, although specific standardization work for different types of medical robots is also felt to be needed.

 

Medical robots have been defined as "robots or robotic devices intended to be used as ME equipment or as MES". So as to explore the various issues involved in in medical robot standardization, three types have been investigated by JWG 9: radiotherapy, surgery and rehabilitation robots.

 

Since it began meeting in 2011 JWG 9 has developed a working definition for the degree of autonomy as a "numerical metric based on the properties and capabilities of the ME equipment indicating the level of the autonomy". This provides a framework for handling autonomy of ME equipment via 4 sub-tasks:

  • Monitoring: assessing all information, sensing and other data relevant to assessing status of ME equipment, patient or operator
  • Generating: formulating options or task strategies for achieving predefined goals
  • Selection: deciding on a particular option or strategy; and
  • Execution: carrying out the chosen option through control actions at an interface

It is possible to organize these 4 steps in different ways and example methods have been developed, based on descriptive and numerically weighted approaches and characterizing the varying degree of autonomy, to assist manufacturers with the risk management process.

Emerging functionality calls for new TR

JWG 9 looked at existing ME equipment and MES that have robotic characteristics and examined the suitability of the existing standards in addressing hazards that might be associated with the systems' use. It was concluded that IEC 60601-1, Medical electrical equipment, ISO 14971, Application of risk management to medical devices, IEC 62366, Medical devices - Application of usability engineering to medical devices, and IEC 62304, Medical device software - Software life cycle processes, provide appropriate general requirements and guidance on how to address these hazards.

 

However, emerging functionality associated with increased autonomy in ME equipment may result in situations in which basic safety and essential performance during use can no longer be assured by the operator. Current ME equipment standards do not fully address this mode of operation and a new TR (Technical Report) is needed to provide guidance for manufacturers and others in this field. Incorporation of higher levels of autonomy in ME equipment and MES is still new and rapidly evolving and it is felt that the Technical Report does not currently lend itself to general standardization. In addition, the need for particular standards for the 3 types of medical robots identified (radiotherapy, surgery and rehabilitation robots) has been assessed with reference to ISO 13482, a new safety standard for personal care robots that is due to be published soon.

 

In view of these overall issues, JWG 9 has recently presented its report to the SC 62A plenary meeting (held in Shanghai from 8-19 April 2013) for the standardization work needed at horizontal and vertical levels. The proposals are as follows:

  • Technical Report on ME equipment and MES employing a degree of autonomy, with the intention of developing it to a Technical Specification and/or a horizontal Standard under SC62A in due course, and
  • specific standards on different categories of medical robots, e.g. Radiotherapy robots under SC 62C: Equipment for radiotherapy, nuclear medicine and radiation dosimetry, and Surgery robots and rehabilitation robots under SC 62D: Electromedical equipment

Full workload in coming years

In spite of their high purchase prices, medical robotic systems are cost-effective as they cut some hazards (such as surgical complications, postoperative infections or bleeding) and the overall length of hospitalization. The fact that they are now being introduced in many developing countries is further proof that they are seen as making economic sense.

 

Transparency Market Research has estimated the global medical robotic systems market at USD 5,48 billion in 2011, with surgical robots forming the largest segment at USD 3,77 billion. It expects the market to grow at a CAGR (compound annual growth rate) of 12,6% from 2012 to 2018 to reach USD 13,64 billion in 2018, with the market for surgical robots worth USD 8,47 billion.

 

This exceptional expansion of the medical robotic market suggests a heavy workload for IEC SC 62A/JWG 9 experts for years to come.

 

  • Surgeons operating using a da Vinci Si Surgical System (Photo: ©2011 Intuitive Surgical, Inc.)
  • Locomat robotic rehabilitation system (Photo: Hocoma, Switzerland)
  • Robotic exoskeleton (Photo: Ekso Bionics™).

 

 

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