The main objective of this project is the development of breast cancer imaging methods using a rotating gamma camera for SPECT (single photon emission computed tomography). The gamma camera consists of a CdZnTe detector and a tungsten or lead slat collimator; therefore this solid-state detector does not use photomultiplier-tubes. Instead of using a parallel-hole collimator, a set of parallel slats that define a series of planes are used to collimate the incoming photons. As a result, the measured projection data are planar integrals as opposed to the line integrals that are generally encountered in traditional Anger camera applications. One advantage of this new gamma camera is its higher energy resolution (about 3% FWHM at 140 keV photopeak) than a regular Anger camera (about 10% FWHM at 140 keV photopeak). Therefore we are able to acquire nearly Compton scatter free data. Another advantage is that the resultant SPECT image will be local. This means that the reconstructed region-of-interest (ROI) is not affected by the radioactivities outside the ROI and in other organs. The radioactivities in the heart and liver are usually high and usually contaminate the projection data of the breast. Our reconstruction algorithm is able to exclude the activities outside the ROI. The overall goal of the project is to develop efficient and accurate three-dimensional SPECT reconstructions for breast imaging using the new CdZnTe camera. The work has the potential to significantly improve the detection of small cancerous lesions in the breast, and significantly improve the diagnostic capabilities of SPECT imaging of the breast. This proposal promotes the development of very novel (high risk, high gain) technologies, including continued support for their maturation and full exploitation, and promote system integration of technologies for targeted applications.
