Acquisition, Storage, Analysis and Retrieval of IR-Thermal Images For Medical Diagnostics

Antoni Nowakowski

Department of Biomedical Engineering

Gdansk University of Technology

ul. Narutowicza 11/12, 80-952 Gdansk, Poland

antowak@biomed.eti.pg.gda.pl

ABSTRACT:

Active Dynamic Thermography, the InfraRed thermal imaging based on analysis of thermal transients after external excitation, heating or cooling, is a new visualisation modality in medical applications. It is especially important in diagnostics of superficial structures, easy reacting to heat transfers, because this is a fully safe and aseptic modality. Therefore our research is oriented to diagnostics of skin burns, surgery interventions and even open-chest cardiosurgery procedures.

The data acquisition procedure requires application of a modern measurement thermal camera, with the resolution at least 0,1 ⁰C and the image frame rate at the level of 30 s^-1, synchronised with an external heating or cooling source. Usually series of thermal images are acquired at the phase of natural relaxation after excitation.

To store such series of images, not loosing basic information of measurement conditions, the DICOM standard was adapted. This is again a new approach as up today DICOM was not including thermal cameras.

For analysis of the knowledge hidden in series of thermal images, which are showing thermal transient processes, a proper model of a tested organ/tissue is of high importance. This is the first step for development of thermal tomography procedures. Simulation of the measurement procedure for a model and comparison the result with measurement data allows to modify the model, leading finally to reconstruction of the measurement object.

Another approach is calculation of parametric images from series of thermograms, such as images of thermal time constants. Then, using knowledge of former data and recognised, well-described cases and experiment results the procedure of classification and automatic recognition of affected regions may be applied. This procedure allows e.g. classification of regions for surgical intervention in skin burn treatment.

Some results of animal experiments as well as clinical data of cardiosurgery procedure monitoring and of skin burn diagnostics will illustrate the presentation.