Does the temperature gradient correlate with the photodynamic diagnosis parameter numerical colour value (NCV)?

Photodynamic diagnosis (PDD) as well as thermovision belong to the category of non-invasive optical diagnosis techniques. Among many different skin cancer diseases, basal cell carcinoma (BCC) is the most frequently occurring one (almost 95% of all skin tumours). In contrast, seborrhoeic keratosis represents almost 70% of benign skin tumours. In this paper we present infrared thermography as an additional method, combined with PDD, to show the differentiation between these two skin mutations.

The photodynamic diagnosis studies were performed by using the autofluorescence diagnosis system Xillix Onco. As an additional non-invasive diagnosis technique, thermovision studies were performed. Thermal imaging was done by using a Thermovision Camera A40M with a sensitivity of 0.07K. The thermograms of the chosen areas were performed in a special room with a temperature of 22.5±1°C. All patients were treated in the Chair and Clinic of Internal Diseases, Angiology and Physical Medicine in Bytom. Thirteen skin lesions were studied: 9 diagnosed as basal cell carcinoma and 4 as seborrhoeic keratosis. All skin lesions were confirmed in histopathological examinations.

The results of the studies revealed significant differences in skin thermal mapping between patients suffering from basal cell carcinoma and seborrhoeic keratosis. It appears that benign skin lesions are characterised by a lower mean temperature than the surrounding healthy skin. To the contrary, cancerous skin mutations appeared on the thermal map at a higher mean temperature. Thermal images for the chosen skin lesions and temperature parameters derived from the thermograms are contiguous with the photodynamic diagnosis results and may give some additional diagnostic information.