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Research paper : Improving the reliability of temperature measurements taken with clinical infrared ear thermometers (J. Ishii)−58−Synthesiology - English edition Vol.1 No.1 (2008) and was directly reflected in the uncertainty of calibration of working standard BBR. Therefore, since the realization of calibration uncertainty of 0.07 °C or less, which was set as a development goal, became difficult to achieve, we could not employ this calibration scheme. I think this method should be reconsidered if the transfer standard (radiation thermometer) with a higher stability and reproducibility can be successfully developed in the future.・On method of transporting blackbody cavityIn case of BBR for ear thermometer a blackbody cavity which is thermal radiation source is placed in a thermostatic water bath with sufficiently good temperature uniformity and stability, and temperature of water near the bottom of the cavity is measured using calibrated a reference thermometer. With the thermostatic fluid bath, it is possible to realize temperature uniformity of about 0.01 °C using devices available commercially, and for long-term management of performance, parameters such as the temperature distribution in the water bath can be checked regularly using a contact thermometer with high temperature resolution such as the reference thermometer.On the other hand, effective emissivity of the blackbody cavity is its performance index which is expected to change greatly not only due to the shape and the material of the cavity but also by the optical property and the deterioration of coating of the inner wall of the cavity, and it is not easy for thermometer manufacturers or testing institutions to quantitatively assess on their own. Therefore, it will actually be possible to calibrate the effective emissivity of blackbody cavity, if it is possible to remove the blackbody cavity from the working standard BBR of the manufacturer, transport it to AIST, install it in the thermostatic water bath of AIST in which the performance is examined, and conduct comparison measurements of radiance temperature with the BBR (blackbody cavity) of national standard. In this case, the client of the calibration service will have a merit of not having to transport large thermostatic water bath system, and will be also able to conduct the long-term measurement management within the company through a group management method by using a set of exchangeable (standard) blackbody cavities calibrated against national standard BBR.If this calibration scheme could be realized, it would have been a unique and practical traceability system in the world for the effective emissivity of blackbody cavity, but survey showed that existing working standard BBR at thermometer manufacturers have wide variation in shape and specification of blackbody cavity, and there were reports of difficulty in removing and transporting the cavity part in manufacturer’s BBR, so we could not put it to practice.3 Trend of international standardQuestion (Akira Ono)The main subject of this article was measurement standard for ear thermometer, but standardization (document standard) is also an important point. What is the state of international industrial standards for ear thermometers?Answer (Juntaro Ishii)As mentioned in the paper, JIS for Japan, ASTM for the United States, and EN for Europe are established as product standards for ear thermometer.From 2005, the work for new international standardization is in progress through a joint proposal by ISO and IEC, mainly for clinical electrical (thermistor) and ear thermometers. For this international standardization, the author is participating in an international working group activity as an expert member. The following committee draft document has been issued as of October 2007.ISO/IEC CD.2 80601-2-56, “Medical Electrical Equipment Part 2-56, Particular requirements for basic safety and essential performance of clinical thermometers for body temperature measurement”, ISO/IEC (2007).4 Use of ear thermometer for preventing spread of infectious diseaseQuestion (Akira Ono)We’ve been warned that if bird influenza virus mutates and spreads around the world, it will be a major threat to humankind. When SARS epidemic occurred in 2003, the experiences of Taiwan, Singapore, China, and Hong Kong where the infection spread within the country may be valuable for Japan in the future. What do you think are the important points for body temperature measurement in public places? Also what role do you think ear thermometers will play?Answer (Juntaro Ishii)Immediately after SARS epidemic became a social problem in the Asian region in 2003, the author actually visited the metrology institutes in Singapore and Taiwan, and gathered information on case studies for screening infected patients with fever at such as international airports. All countries screened patients with fever of 38.0 °C or higher, and inspection using infrared thermographic instruments and ear thermometers were conducted.From these case studies and discussion with persons involved, technical issues in public screening were: (1) maintaining stability of thermography and ear thermometer, and (2) efficient and reliable screening using combination of sensing devices. For (1), in contrast to laboratory with stable environmental condition, it was difficult to maintain reliability of the instrument (temperature reading) in places with severe fluctuations in environmental condition such as humidity and temperature. At the airport in Singapore, screening was done by installing improved thermography system in the passageway to the immigration counter, but the temperature reading of the thermograph image was not sufficiently stable. A simple BBR was placed behind the passageway, so people and blackbody cavity could be observed simultaneously by the thermography to make corrections of drifts of temperature scale of thermograph image. For (2), to conduct efficient and highly reliable screening on a large number of people, preliminary screening using thermography system was conducted, and full inspection using ear thermometer was conducted to people suspected of a fever, and this prevented giving stress to the travelers.These cases and technical issues would be highly suggestive for operating public screening in Japan.5 Shape and surface coating of standard blackbody cavityQuestion (Akira Ono)It is written that the blackbody cavity for ear thermometers Fig. c Standard blackbody cavity for ear thermometer developed by AISTunit:mm120 °50 °200φ60φ20

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