NPL contributions to the standardisation and validation of contemporary medical thermometry methods

Since the advent of reliable mercury-in-glass thermometers in the latter part of the 19th century the practice of clinical thermometry was thought to be a solved issue. However with advances in technology there has, in recent decades, been a proliferation of temperature measurement methods applied to medical science. Many of these have been introduced because of the clinical benefit they confer, nevertheless, in some cases the metrological foundation and infrastructure to ensure sound measurement was not in place. This paper will focus on the standardisation activity undertaken by the UK's National Physical Laboratory (NPL) to support reliable temperature measurement, using a number of innovative methods, in a clinical setting.

Thermodynamic temperature assignment to the point of inflection of the melting curve of high-temperature fixed points

The thermodynamic temperature of the point of inflection of the melting transition of Re-C, Pt-C and Co-C eutectics has been determined to be 2747.84 ± 0.35 K, 2011.43 ± 0.18 K and 1597.39 ± 0.13 K, respectively, and the thermodynamic temperature of the freezing transition of Cu has been determined to be 1357.80 ± 0.08 K, where the ± symbol represents 95% coverage. These results are the best consensus estimates obtained from measurements made using various spectroradiometric primary thermometry techniques by nine different national metrology institutes. The good agreement between the institutes suggests that spectroradiometric thermometry techniques are sufficiently mature (at least in those institutes) to allow the direct realization of thermodynamic temperature above 1234 K (rather than the use of a temperature scale) and that metal-carbon eutectics can be used as high-temperature fixed points for thermodynamic temperature dissemination. The results directly support the developing mise en pratique for the definition of the kelvin to include direct measurement of thermodynamic temperature.

Dissemination of thermodynamic temperature above the freezing point of silver

The mise-en-pratique for the definition of the kelvin at high temperatures will formally allow dissemination of thermodynamic temperature either directly or mediated through high-temperature fixed points (HTFPs). In this paper, these two distinct dissemination methods are evaluated, namely source-based and detector-based. This was achieved by performing two distinct dissemination trials: one based on HTFPs, the other based on absolutely calibrated radiation thermometers or filter radiometers. These trials involved six national metrology institutes in Europe in the frame of the European Metrology Research Programme joint project 'Implementing the new kelvin' (InK). The results have shown that both dissemination routes are possible, with similar standard uncertainties of 1-2 K, over the range 1273-2773 K, showing that, depending on the facilities available in the laboratory, it will soon be possible to disseminate thermodynamic temperatures above 1273 K to users by either of the two methods with uncertainties comparable to the current temperature scale.

Streptococcal necrotising myositis of obturator internus and piriformis in a type 2 diabetic patient presenting as sepsis of unknown origin

This report describes a case of necrotising myositis of the obturator internus and piriformis muscles. Necrotising myositis is a rare result of group A streptococcal infection. It is usually fatal and has not been described previously in the obturator internus and piriformis. We describe how, following presentation to an emergency department, rapid diagnosis was arrived at by clinically guided radiological investigation. The report considers the possible aetiology of the condition, the diagnosis and its management, and reviews the relevant literature.