Nowy standard w badaniach przesiewowych stanów zapalnych przy użyciu termowizji
New Standard for Fever Screening with Infrared Thermography
E.F.J.Ring, A Jung, J Zuber

    Medical Imaging Research Unit, Faculty of Advanced Technology, University of Glamorgan Wales, United Kingdom.
    Influenza virus infections are a regular part of human life, but periodically a more virulent strain occurs with rapid and fatal consequences for humans. Since the outbreak of severe Acute Respiratory Syndrome SARS in China in 2002-3, infrared imaging has been used in some airports in South East Asia for screening passengers before travelling whilst suffering from a fever.
    In 2004 Singapore Standards authority SPRING produced two documents as technical references. Thermal Imagers for Temperature Screening part1 requirements and test methods, and Part 2 Implementation Guidelines, were the first documents to focus on the required information for the application of this technology for fever screening. These were used as the basis for a new working group for the International Standards Organization. The content of the Singapore documents were updated and expanded to provide a new standard for the correct deployment of thermal imaging for fever detection.
    Many of the first installations were (and still are) positioned in a way that reduces the efficiency of temperature measurement. Strict protocols, as in medical thermography, are the key to reliable and reproducible use of the technique. Proper understanding of the conditions for installation and use are essential, as are the regular testing of camera performance and training of personnel involved. The new document is called "Particular requirements for the basic safety and essential performance of screening thermographs for human febrile temperature screening" IEC80601-2-59and ISO subcommittee SC3. and was published after an international vote in September 2008.
    A second document based on the SPRING document Part 2, was published in March 2009. This is not an international standard as such, but a technical guide to the "Deployment, implementation and operational guidelines for identifying humans using a screening thermograph". ISO/IEC TC 121/SC 3 N.
    The ISO standard sets out the technical minimal performance required for a thermographic system used for fever screening. It refers to a number of existing standards relating to calibration of cameras, use of black body radiators etc. and the optimal performance needed to image to face and measure as accurately as possible. The inner canthi area of the eyes is a preferred and recommended site to represent core temperature. The procedure requires correct positioning so that the face fills the majority area of the image. It also requires a minimal number of pixels in the measured area, to derive the temperature. This contrasts with many of the pictures shown in the media where the camera may be directed at groups of people, and maximum temperature displayed in a thermogram may be based on a single pixel. Many images shown in thermograms drawn from image libraries by the media are of low resolution, probably out of focus, and the subject is too far away to measure temperature. The main items of these documents will be described and their importance to the future use of medical thermography will be discussed. At the present time the H1N1/A virus alert has resulted in more thermography installations, although it is likely that many will not yet be used in compliance to the new standard.
    A consortium of European experts is proposing to further investigate the issues surrounding the types of temperature measurement that ca be used for fever detection, and to apply the new standard for thermographic screening as should be applied in an airport location. A current study in Warsaw with thermographic studies on the face in children, indicates that the inner canthi of the eyes are an excellent location for temperature detection in fever cases, that correlates with clinical thermometry.