Take a look inside
A central aspect of modern medical treatment is the ability to see inside the body and identify lesions or illnesses in a non-invasive manner. The first major advance in this regard was not achieved until the late 19th century with the discovery of X-rays by German physicist Wilhelm Röntgen. These use a form of electromagnetic radiation to provide clear images of bones and of certain organs, such as lungs.
X-rays provided a major advance in medicine but have drawbacks, in particular exposure to radiation that has a carcinogenic effect. Röntgen was conscious of this potential risk and wore protective lead shields, much like those in use today.
A significant improvement in imaging procedures was provided by using high-frequency sound waves and their echoes. Images of internal organs can be produced by measuring the distances covered by the reflected waves, a technique similar to that used to detect submarines.
Improved techniques have been developed to produce 3D images that allow a better look at the organ examined and to calculate blood flow using Doppler ultrasound, which can measure a moving solid or liquid matter. Ultrasound imaging is expanding faster than any other form of medical imaging. However, the use of ultrasound in the medical domain has been extended beyond imaging to include surgery and therapy, dental care, and even the cleaning of certain pieces of medical equipment.
The need for Standards
Work on medical ultrasonic safety Standards started back in 1955, in the early days of clinical use of ultrasounds, within a WG (Working Group) of TC (Technical Committee) 29: Acoustics. This WG was upgraded to SC (Subcommittee) 29D: Ultrasonics, in 1966 and transformed into the full TC 87 in 1985.
Its remit is "to prepare standards related to the characteristics, methods of measurement, safety and specifications of fields, equipment and systems in the domain of ultrasonics". TC 87 brings together experts from 15 participating and 19 observer IEC member countries.
Its publications cover the whole range of equipment used in medical ultrasonics, such as the various types of ultrasonic transducers, which convert energy into ultrasound, and hydrophones, as well as a means of reporting the acoustic output of medical diagnostic ultrasonic equipment. They also cover test procedures and the characteristics of, or requirements for, ultrasonic equipment used for diagnosis, surgery, therapy or physiotherapy.
The safety aspects of medical electrical equipment and systems do not fall within the scope of TC 87 but of IEC TC 62: Electrical equipment in medical practice, and its SCs. TC 87 therefore maintains close liaison with TC 62 in fields of common interest. It uses Standards created by SC 62D/MT 18: Therapy equipment, and is a provider of Standards to that SC.
TC 87 is also a supplier of Standards to the following TC 62 SCs:
- SC 62A: Common aspects,
- SC 62B: Diagnostic imaging equipment, which is working on a revision of IEC 60601-2-37, Particular requirements for the basic safety and essential performance of ultrasonic medical diagnostic and monitoring equipment,
- SC 62D: Electromedical equipment, which includes work on extracorporeal lithotripsy equipment used to treat kidney stones.
Safe imaging and other applications
Ultrasonic imaging is invaluable in obtaining views of soft tissues and muscles and does not have known long-term side effects; it is also relatively inexpensive in comparison with other imaging modes such as MRI (magnetic resonance imaging) or X-ray CT (computed tomography). It is generally considered very safe, including for foetuses. As a result, it is the only imaging method used widely during pregnancy in obstetrics and neonatal medicine.
The range of ultrasonic applications in the medical field has now extended well beyond imaging and diagnostics to include surgery, non-invasive therapeutic applications and targeted drug delivery (see article in this e-tech for details of ultrasonics use in medicine).
However, if the most visible and demanding ultrasonic applications today are in the medical field, TC 87 prepares also Standards outside the medical field, these include:
- underwater acoustics, with Standards for hydrophones, used in equipment such as sonar devices, systems for tracking shoals of fish and other deepwater-based survey tools.
- cleaning equipment, TC 87 published IEC/TR 60886, a Standard to test the effectiveness of ultrasonic cleaners, which are not only used in medical but also in industrial applications.
- transducers, as these are not unique to medical usage, but can be incorporated in any relevant application.
Standardization to sustain growth
Given this expansion in the range of medical ultrasonic applications and its rapid pace of growth, helping drive a steady rise of the market from an estimated USD 5,6 billion in 2011 to a predicted USD 8,1 billion by 2017, standardization for ultrasonic medical equipment is increasingly important.
As a result, the 94 TC 87 experts, currently preparing International Standards in the ultrasonic field can expect to have a busy agenda in coming years.