Testing and performance standards for elevated skin temperature  (EST) screening systems using infrared cameras

Schmidt, Matthew F.; Liebmann, Frank; Menenberg, Max; Rahman, Syed Mizanur; Holz, Thomas A.; Bergstrom, Pete; Gust, Jeff

doi:10.1117/12.2589024

Cited by 4 publications

(4 citation statements)

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“…It features a multi‐spectral dynamic imaging (MSX) mode that merges visible light and thermal images to increase the level of detail in the image. It has thermal resolution of 160 × 120 pixels, visual resolution of 640 × 480 pixels, angle of view of 50° ± 1°/43° ± 1°, and thermal sensitivity/noise equivalent temperature difference (NETD) of 0.07°C/70 mK 17 . During the course of the SPT, the room temperature was maintained at 23°C.…”

Section: Methodsmentioning

confidence: 99%

“…It has thermal resolution of 160 × 120 pixels, visual resolution of 640 × 480 pixels, angle of view of 50° ± 1°/43° ± 1°, and thermal sensitivity/ noise equivalent temperature difference (NETD) of 0.07°C/70 mK. 17 During the course of the SPT, the room temperature was maintained at 23°C. The patient's forearms were positioned on a table with the smartphone-based thermal camera placed above them at a distance of 40 cm.…”

Section: Spt and Thermographical Imaging Measurementsmentioning

confidence: 99%

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Thermo‐SPT: A new skin prick test evaluation framework based on low‐cost, portable smartphone thermography

Goktas

Bostan

Gülseren

et al. 2023

Clin Experimental Allergy

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Background: Although the skin prick test (SPT) is a reliable procedure to confirm IgEdependent allergic sensitization in patients, the interpretation of the test is still performed manually, resulting in an error-prone procedure for the diagnosis of allergic diseases.Objective: To design and implement an innovative SPT evaluation framework using a low-cost, portable smartphone thermography, named Thermo-SPT, to significantly improve the accuracy and reliability of SPT outcomes.Methods: Thermographical images were captured every 60 s for a duration of 0 to 15 min using the FLIR One app, and then analysed with the FLIR Tool ® . The definition of 'Skin Sensitization Region' area was introduced to analyse the time-lapse thermal changes in skin reactions over several time periods during the SPT. The Allergic Sensitization Index (ASI) and Min-Max Scaler Index (MMS) formulae were also developed to optimize the identification of the peak allergic response time point through the thermal assessment (TA) of allergic rhinitis patients.Results: In these experimental trials, a statistically significant increase in temperature was detected from the fifth minute of TA for all tested aeroallergens (all p values < .001).An increase was observed in the number of false-positive cases, where patients with clinical symptoms not consistent with SPT were evaluated as positive on TA assessment, specifically for patients diagnosed with Phleum pratense and Dermatophagoides pteronyssinus. Our proposed technique, the MMS, has demonstrated improved accuracy in identifying P. pratense and D. pteronyssinus compared with other SPT evaluation metrics, specifically starting from the fifth minute. For patients diagnosed with Cat epithelium, although not statistically significant initially, an increasing trend was determined in the results at the 15 min (ΔT (T 15 − T 0 ), p = .07; ASI T15 , p < .001).

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Section: Methodsmentioning

confidence: 99%

Section: Spt and Thermographical Imaging Measurementsmentioning

confidence: 99%

Thermo‐SPT: A new skin prick test evaluation framework based on low‐cost, portable smartphone thermography

Goktas

Bostan

Gülseren

et al. 2023

Clin Experimental Allergy

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“…To our knowledge, all but one system for body thermometry (out of several dozen we are aware of) use a fixed correction factor that is not dependent on ambient temperature{16}. It is unclear why this is the case, but the relevant medical standards do not discuss any dependence of the correction factor on other confounds, again relying on clinical study to qualify a system as sufficiently accurate, among other issues recently raised regarding the ISO febrile standard{16,17,18}. The strength of an ISO consensus standard{7}, relying on diverse input in its creation, may have led scientists and system designers to assume a fixed offset was indeed sufficient.…”

Section: Introductionmentioning

confidence: 99%

“…The screening standard describes laboratory measurements for an IRT system comprised of either an IR camera with sufficient absolute accuracy or an IR camera paired with an IR calibration source (blackbody) to achieve a total system uncertainty of ±0.5C. Recent publications have pointed out shortcomings in the standard and proposed enhancements or modifications{16,17,18}. As discussed earlier in the introduction and results from our pilot study{36}, the lack of an ambient-dependent adjustment is a major confound for both IRT and NCIT devices.…”

Section: Introductionmentioning

confidence: 99%

Principles and test methods of non-contact body thermometry

Beall¹,

Askegaard

Berkesch

et al. 2022

Preprint

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Significance: Far infrared (IR) has a long history in thermometry and febrile screening. Concerns have been raised recently over the accuracy of non-contact body thermometry. Clinical testing with febrile individuals constitutes the standard performance assessment. This is challenging to replicate, which may have inadvertently allowed approval of IR systems that are unable to detect fevers. The ability to test performance without relying on febrile participants would have ramifications for public health, especially if this discovered undisclosed differences in accuracy in widely used devices. Aim: Identify foundational issues in, demonstrate principles of, and develop test methods for non-contact body thermometry. Approach: We review foundational literature and identify confounds impeding performance of IR thermography (IRT) and non-contact IR thermometry (NCIT) for febrile screening and demonstrate corrections for their effects, which would otherwise be unacceptable. Almost none of the devices we are aware of compensate for these confounds. We reverse-engineer surface-to-body temperature relations for several FDA-cleared NCITs. We note their similarity to recently reported bias-to-normal behavior in other devices and determine range of body temperatures for which the device would produce a "normal" (non-febrile) output. Finally, we generate predictable elevated face temperatures in healthy subjects and demonstrate this in several devices. Results: The surface-to-body relationships for two IRT and one NCIT were linear, while all others exhibited nonlinear bias-to-normal behavior that produce normal temperatures when presented with surface temperatures ranging from hypothermia to moderate-to-severe fever. The test method was used in healthy, non-febrile subjects to generate elevated temperatures corresponding to body temperatures from 97.35F to 102.45F. Three out of five systems had negligible sensitivity. Conclusions: This demonstrates an alternative evaluation method without the limitations and risks of febrile patients. These results indicate many devices may be unusable for body thermometry and may be providing a false sense of security for public health surveillance.

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Pixel luminance artifact measurement, calibration, and correction for accurate thermographic body temperature determination

Beall

2021

Infrared Sensors, Devices, and Applications XI

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Testing and performance standards for elevated skin temperature (EST) screening systems using infrared cameras

Cited by 4 publications

References 0 publications

Thermo‐SPT: A new skin prick test evaluation framework based on low‐cost, portable smartphone thermography

Thermo‐SPT: A new skin prick test evaluation framework based on low‐cost, portable smartphone thermography

Principles and test methods of non-contact body thermometry

Pixel luminance artifact measurement, calibration, and correction for accurate thermographic body temperature determination

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