Optical tomography in the diagnosis of rheumatoid arthritis - method and implementation

Optical tomography is a method sensitively responding to changes in the finger joints in the early stage of rheumatoid arthritis. To improve the clearness of both the findings and the spatial resolution of the images, as much information as possible is to be obtained on the radiation transport through the joint and put into the image reconstruction procedure. Compared to time integral measurements, a frequency domain transillumination method offers additional measurands based on which an improved representation can be expected. As the image reconstruction is based on the calculation of the radiation transport inside the body, the limits of the body transilluminated have to be exactly known. Therefore, the acquisition of the outer finger geometry is of particular importance. In order to test the reconstruction algorithms and for the reproducibility of test measurements, the use of suitable phantoms of different abstraction degree is indispensable.