A NEW APPROACH TO VERY HIGH-RESOLUTION MINI-BRAIN PET USING A SMALL NUMBER OF LARGE DETECTORS

A new very high resolution Positron Emission Tomography using only a small number of large detectors in a circular ring format with collimating apertures is proposed and a design example is given. The proposed system is ideally suited for very high resolution brain imaging i.e. close to 2 mm fwhm resolution and can be converted to a medium resolution system by simply changing the size of collimating aperture if higher sensitivity operation is desired. The basic concept of the system design is the optimization of the detector size and system diameter. The former relates to the detection efficiency and photon spillage and penetration to adjacent crystals, while the latter (system diameter) relates to the overall system sensitivity. Since conventional sampling schemes are unlikely to satisfy the sampling requirements for such a system where only a small number of large detectors are arranged in a circular ring format, therefore, we have developed a Sequentially arranged Collimating Aperture Rotating-ring Detector (SCARD) scheme which allows us to sample the object space fine enough for image reconstruction. Copyright © 1990 by The Institute of Electrical and Electronics Engineers, Inc.