Traceability and calibration in temperature measurement: a clinical necessity

Simpson, Robert L.; Machin, G.; McEvoy, H C; Rusby, R. L.

doi:10.1080/03091900600711530

Cited by 26 publications

(20 citation statements)

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“…This has resulted in a decreased use of mercury in glass and an increased take-up of the electronic thermistor and infrared devices. Although issues of standardization and traceability were not initially addressed in respect to the newer electronic devices [4], from the user's point of view the electronic devices tend to be at least as easy to use as the mercury in glass thermometer. They also have the added advantages of being faster at producing a temperature *Corresponding author.…”

Section: Historical Perspectivementioning

confidence: 99%

The vagaries of ear temperature assessment

McCarthy

Heusch

2006

Journal of Medical Engineering & Technology

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There have been a growing number of reports suggesting that ear temperature measurement is unreliable and by implication so is the device. Examination of the measurement site, the tympanic membrane (eardrum) and the walls of the external auditory meatus (ear canal) reveals that at least some of the unreliability might derive from poor aiming of the infrared thermometer: the ear canal walls have a lower temperature than the eardrum. Additionally, anatomical properties of the ear canal may increase the difficulty of aiming the thermometer at the eardrum. Furthermore, the rich vascularization, innervation and variations in skin properties (thickness, oil secretion and hair) along the length of the ear canal affect the black body-like nature of the structure. It is concluded that such factors are more likely underlying reasons for the difficulties in reliably reproducing temperatures from this site. We conclude that concerns should extend beyond the reliability of the device and there should be greater study of the measurement site. The argument extends to all sites chosen for clinical assessment of the patient, as previous studies of the alternative temperature measurement sites are also unfortunately few and tend to be lacking in scientific rigour.

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Section: Historical Perspectivementioning

confidence: 99%

The vagaries of ear temperature assessment

McCarthy

Heusch

2006

Journal of Medical Engineering & Technology

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“…However, previous work by National Physical Laboratory (NPL) assessing the performance of thermal imagers used in medical thermography identified poor or non-existent traceability to ITS-90 with a temperature dispersion between the imagers in the region of ±2 • C [1]. The disparity was much larger than expected by the medical thermography community and would be very significant for any work involving absolute rather than relative temperature measurement, such as standardization, charting patient progress (either of the disease or of the response to treatment), and image comparison in-center and cross-center.…”

Section: Introductionmentioning

confidence: 95%

“…In response to this, NPL has been working with UK medical thermographers to put in place a robust traceability regime [1]. The developments described here are the next step in putting clinical thermography on a firm traceable basis.…”

Section: Introductionmentioning

confidence: 97%

In-Field-of-View Thermal Image Calibration System for Medical Thermography Applications

et al. 2008

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Medical thermography has become ever more accessible to hospitals, medical research, and clinical centers with the new generation of thermal cameras, which are easier to use and lower in cost. Some diagnostic techniques using thermal cameras are now regarded as standardized, such as the cold challenge test for Raynaud's phenomenon. The future for medical thermography appears to be improved accuracy, standardization, and establishment as a mainstream medical imaging methodology. Medical thermography standardization, quantitative measurements, image comparison, and multi-center research trials all require thermal cameras to provide a demonstrably traceable, accurate, and reliable temperature output. To this end, the National Physical Laboratory (NPL) has developed a multi-fixed-point source that serves as an in-image calibration system, thereby providing a reliable means for radiometric image validation. An in-field-of-view fixed-point validation system for thermal imaging has successfully been developed, tested, and validated at NPL and has undergone field trials at three clinical centers in the UK. The sources use the phase change plateaux of gallium-zinc eutectic, gallium, and ethylene carbonate. The fixed-point sources have an estimated cavity emissivity of greater than 0.998, a plateau longevity of nominally 3 h at ambient conditions, a stability of 0.1 • C, or better, over that period, a repeatability of 0.1 • C or better, and an estimated temperature uncertainty of ±0.4 • C (k = 2). In this article, the source specifications and design as well as testing, validation, and field trial results are described in detail.

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“…Some authors highlighted the key role of metrological traceability of sphygmomanometers as a tool for reducing healthcare costs and improving patient's care [13][14][15]. Similarly, other researchers pointed out the need for traceability in clinical temperature results [16][17][18]. With respect to ophthalmic diseases, the evaluation of metrological concerns related to tonometers is under investigation [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the role of metrological traceability in health care: a comparison study by statistical approach

Ferreira

Matos²,

Puga-Leal³

2015

Accred Qual Assur

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To evaluate the role of metrology in healthcare facilities, a study was performed among Portuguese hospitals to identify and analyze issues concerning the concept of metrological traceability. The discussion is structured around a dataset obtained from a survey questionnaire covering 44 public and private Portuguese hospitals. The principal results of our analysis include identifying some key indicators that apply to certified/accredited hospitals. Test reports and calibration certificates were the main metrological traceability documents required by the hospitals. The acquisition of medical measuring instruments with conformity reports depended on the type of hospital. Maintenance was considered the most relevant issue for private hospitals, whereas for the public hospitals, this issue is less important than trust in the supplier. For public hospitals, purchase price was the most important requirement. For hospitals that acquire calibrated measuring instruments, only 50 % perform in-house calibration. We conclude that trust in supplier is associated with a lower overall budget for maintenance operations. The protocol established by hospitals to acquire measurement instruments does not reflect metrological concerns, and the relationship between maintenance and metrological operation is not well established. Thus, we conclude that metrological traceability is largely absent in the daily considerations of healthcare professionals and facilities.

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Traceability and calibration in temperature measurement: a clinical necessity

Cited by 26 publications

References 1 publication

The vagaries of ear temperature assessment

The vagaries of ear temperature assessment

In-Field-of-View Thermal Image Calibration System for Medical Thermography Applications

Evaluation of the role of metrological traceability in health care: a comparison study by statistical approach

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