MICROWAVE TOMOGRAPHY - 2-DIMENSIONAL SYSTEM FOR BIOLOGICAL IMAGING

Microwave tomographic imaging is one of the new technologies which has the potential for important applications in medicine, Microwave tomog raphically reconstructed images may potentially provide information ab out the physiological state of tissue as well as the anatomical struct ure of an organ, A two-dimensional (2-D) prototype of a quasi real-tim e microwave tomographic system was constructed, It was utilized to rec onstruct images of physiologically active biological tissues such as a n explanted canine perfused heart, The tomographic system consisted of 64 special antennae, divided into 32 emitters and 32 receivers which were electronically scanned, The cylindrical microwave chamber had an internal diameter of 360 mm and was filled with various solutions, inc luding deionized water, The system operated on a frequency of 2.45 GHz , The polarization of the incident electromagnetic field was linear in the vertical direction, Total acquisition time was less than 500 ms. Both accurate and approximation methods of image reconstruction were u sed, Images of 2-D phantoms, canine hearts, and beating canine hearts have been achieved. In the worst-case situation when the 2-D diffracti on model was used for an attempt to ''slice'' three-dimensional (3-D) object reconstruction, we still achieved spatial resolution of 1 to 2 cm and contrast resolution of 5%.