Infrared thermal imaging camera to measure low temperature thermal fields.

To measure low-temperature thermal fields, we have developed a single-element cooled thermal imaging camera for a spectral range of 8-14 µm with an internal shutter for radiometric calibration. To improve the accuracy of measuring the temperature of cold objects, we used a shutter with a combined emissivity as an internal reference source of radiation at the input of the device optical unit. With this aim a small mirror was fixed in the center on its surface covered black, thereby ensuring an efficient reflection of radiation in a wide spectral range of wavelengths. When processing the signal for each pixel of the thermal image, the differential value of the detector response to the shutter blackened and mirror areas was used as a reference. A relative measurement error of 3% was obtained for the studied objects with a temperature of -150 °C. The device was successfully used for remote study of thermal field dynamics during freeze-thawing of biological tissues in vivo.

INFRARED THERMAL IMAGING CONTROL OF RADIATION DERMATITIS DYNAMICS.

BACKGROUND: Radiation-induced dermatitis impairs the quality of life of cancer patients and may lead to the need of interrupting radiotherapy. The grade of dermatitis is subjectively assessed by the visual examination. There is an urgent need for both objective and quantitative methods for assessing the current grade of dermatitis and predicting its severity at an early stage of radiotherapy. AIM: The aim of the study was to evaluate the advantages and limitations of infrared thermography for monitoring the current level of radiation-induced dermatitis and predicting its severity by quantitative analysis of the thermal field dynamics in the irradiated zone. MATERIALS AND METHODS: 30 adult patients were examined by infrared thermography during the course of 2D conventional radiotherapy for malignant tumors of various types and localizations. Our approach for quantifying the thermal field caused by dermatitis alone was applied. A statistical (correlation and ROC) analysis was performed. RESULTS: Dermatitis of varying severity was observed in 100% of the patients studied. The dynamics in the intensity of the anomalous thermal fields in the irradiated zone correlated with the dynamics of dermatitis grades, excluding the case of a radiosensitive tumor (correlation coefficient 0.74÷0.84). It was found that the maximum toxicity (dermatitis grade ≥ 3) develops in patients who how significant hyperthermia in the area of interest (≥ 0.7 °C) at an early stage of radiotherapy. The ROC analysis demonstrated the "good quality" of the prognosis method (AUC = 0.871). CONCLUSIONS: The non-invasive and cheap infrared thermography is a suitable tool for objective quantitative monitoring the current dermatitis grade during radiotherapy as well as predicting its severity for any tumor location.

A broadband imaging system for research applications.

We have developed a compact, computer-piloted, high sensitivity broadband imaging system for laboratory research that is compatible with various detectors. Mirror optics allow application from the visible to the far infrared spectral range. A prototype tested in conjunction with a mercury cadmium telluride detector exhibits a peak detectivity of 6.7x10(10) cm Hz(1/2)/W at a wavelength of 11.8 microm. Temperature and spatial resolutions of 0.06 K and 1.6 mrad, respectively, were demonstrated.