Feasibility and utility of infrared thermography as a thermometer: Comparison with oral and tympanic thermometry

Abstract

Study objectives: We determine the relationship between infrared thermography (IRT) acquired body surface temperature (BST) values and temperature values obtained by conventional measures (oral and tympanic). Methods: IRT images using a ThermaCAM P60 (FLIR Systems, North Billerica, MA) were obtained for 20 consecutive adult emergency department (ED) patients, regardless of complaint, in a tertiary care center. Patients also had their oral and tympanic temperature measured within 1 minute of IRT imaging. The camera has a spatial resolution of 320×240 pixels in focal plane array, scan integration rate of 60 Hz, and thermal sensitivity of 0.08°C per pixel. Focal distance was 1 m, with a sed in JPEG format. The mean BST using IRT over an area 4 cm 2 was collected and recorded for each patient in 3 distinct anatomic areas using specialized software. Body areas imaged with IRT were the glabella, the abdomen centered at the umbilicus, and the dorsum of a hand. The skin of the abdomen was exposed and allowed to equilibrate with the environment for 2 minutes before IRT, and the imaged hand was contralateral to any intravenous line. The temperature difference (ΔT) for tympanic thermometry and IRT was calculated against oral temperatures (where ΔT=oral temperature – mean BST by IRT for each body region per patient), and the mean ΔT±SD are reported. The coefficient of determination ( R 2 ) was also calculated for each IRT region data set. The institutional review board approved the study, and informed consent was obtained on all patients. All temperatures were recorded in °C. Results: For ΔT-tympanic, the mean was –0.2±0.5°C (SD), the ΔT-glabella mean was 2.2±0.7°C, the ΔT-abdomen mean was 3.3±1.6°C, and for ΔT-hand the mean was 4.4±1.7°C. R 2 values were tympanic 0.629, glabella 0.405, abdomen 0.163, and hand 0.035. Conclusion: With the exception of IRT images of the glabellar region, IRT regional mean BST values appear to correlate poorly with oral thermometry. Some of the variance may be due to technique and environmental temperature interference. Because IRT is fast and easy to obtain, is not associated with radiation, and may convey other important information, additional study to refine IRT technique is warranted.