Fast adaptive screening of breast cancer: Survey on dielectric and loss factor

In the conventional radiography, the image is formed by taking two dimensional projections from a three dimensional body. The imaging technique of X-ray computed tomography has caused a great revolution in the field of medical radiology. But later, combined with sophisticated computer signal processing the image of any cross section of a biological target could be obtained free of interfering shadows from structure within the cross section which cannot obstruct image formation. But gradual awareness of the danger of ionizing radiation made CT using X-ray unsuitable for mass screening of female breast for detection of cancerous tumors. As a result, in recent years much attention has been concentrated on imaging with alternative forms of energy like ultrasound, low level microwaves and NMR. Unfortunately, the qualities of tomographic reconstruction obtained with sound or electromagnetic radiation are inferior to those obtained with X-rays. The inherent success of CT using X-ray lies in the fact that X-rays, being non-diffracting travel in straight line and therefore the projection data measure the line integral of some object parameter along straight lines. This makes it possible to apply a Fourier Slice Theorem, which says that the Fourier Transform of a projection equals to the slice of 2D Fourier Transform of the object.