Evaluation of Performance of Dedicated, Compact Scintillation Cameras

摘要

As part of the development of dedicated scintillation cameras, we compared the performances of 2 dedicated cameras with a standard clinical camera (Siemens Orbiter, with high resolution collimator). The dedicated cameras were based on Position Sensitive Photomultipliers (PSPMTs): first, a single PSPMT coupled to a 6 by 6 by 0.6 cm NaI(Tl) crystal and second, multiple-PSPMTs coupled to a matrix of 2 by 2 by 6 mm NaI(Tl) crystal with hexagonal hole collimator. Image resolution was measured with all cameras as a function of depth. The ability of the cameras to measure small superficial tumors was tested with a phantom consisting of 6 hot cylindrical tumors of height 3 mm and varying diameters against a warm background of 4, 1 cm thick cylinders. Tumors were stepped through the background and imaged at each level, starting at the collimator face, using a tumor to background activity concentration ratio of 10:1 and adjusting the imaging time for each to compensate for decay. Images were made of an anthropomorphic human thorax phantom with simulated breast lesions and detectability between the multi-PSPMT camera and the clinical camera was compared. The improved performance of dedicated cameras in specific tasks suggests that these devices will have a role in scintimammography and assisting in O.R. procedures such as sentinel node dissection and other shallow depth of field applications.