1. A three-dimensional spectral imaging system comprising: a source of collimated radiation disposed at a proximal side of an object; the collimated radiation having a predetermined wavelength; a scanning angle changer operatively connected to at least one of the radiation source and the object; a radiation detector disposed at a distal side of the object; and a processor coupled to the radiation detector, the processor receiving information from the radiation detector and generating a three dimensional spectral image of the object based upon a principal component analysis of the received information.