chapter  7
30 Pages

Quantitative Active Dynamic Thermal IR-Imaging and Thermal Tomography in Medical Diagnostics

Static infrared (IR) thermal imaging has a number of attractive properties for its practical applications in industry and medicine. The technique is noninvasive and harmless as there is no direct contact of the diagnostic tool to an object under test, the data acquisition is simple and the equipment is transportable and well adapted to mass screening applications. There are also some fundamental limitations concerning this technique. Only processes characterized by changes in temperature distribution on external surfaces

Nikolas: “9027_c007” — 2007/6/4 — 20:36 — page 2 — #2

directly accessible by an IR-camera can be observed. The absolute value of temperature measurement is usually not very accurate due to generally limited knowledge of the emission coefficient. Many harmful processes are not inducting any changes in surface temperature, for example, in industrial applications material corrosion or cracks are usually not visible in IR thermographs, in medicine in mammography inspection a cyst may mask cancer, etc. For such cases active dynamic thermal imaging methods with sources of external excitations are helpful. Therefore the nondestructive evaluation (NDE) of materials using active dynamic thermal IR-imaging is extensively studied; see, for example, proceedings of QIRT [1]. The method is already well developed in some of industrial applications but in medicine this technique is almost unknown.