Transmission imaging with a compact gamma camera: initial results for mammotomography

A dedicated single photon emission prototype imaging system is intended for fully 3D Application Specific Emission and Transmission Tomography (ASETT), where one specific application is dedicated breast imaging. In breast imaging, this dual-modality system may be useful for (1) improving detectability of low contrast lesions with X-ray CT imaging, (2) emission quantification using the transmission images, and (3) better interpretation of the reconstructed emission data by facilitating objective region selection. Each imaging component needs independent development, optimization and characterization. The prototype SPECT component using a NaI(Tl) based gamma camera has been built and initially evaluated with small, low contrast breast lesions; resolution and sampling issues ire under investigation with the arbitrary orbits possible with the hemispherical positioning capability.