title: ECAT: a new computerized tomographic imaging system for positron-emitting radiopharmaceuticals.
abstract: The ECAT was designed and developed as a positron imaging system capable of providing high contrast, high resolution, quantitative images in two-dimensional (2-D) and tomographic formats. The flexibility in its variety of imaging problems. High (HR), medium (MR), and low (LR) tomographic resolutions are 0.95 +/- 0.1, 1.3 +/- 0.1, and 1.7 +/- 0.1 cm FWHM; high, medium, and low resolutions in 2-D images are 0.85 +/- 0.1, 1.3 +/- 0.1 and 1.7 +/- 0.1, depending on resolution mode employed. ECT system efficiency is 30,100, 15,900, and 9,200 c/sec/muCi/cc with a 20-cm diameter phantom at LR, MR, and HR. Because of the geometric, detector, electronic and shielding design of the system, count-rate capability and linearity are high, with minimum detection of scattered radiation and random coincidence. Measured error agrees well with theoretical statistical predictions down to a level of 1.4% standard deviation. The redundant sampling scheme of this system significantly reduces errors caused by motion and detector instability. Scan times are variable from 10 sec to several min/slice and multiple levels are automatically performed by computer control of patient bed. A variety of human studies illustrate image quality, resolution, and efficiency of both ECT and 2-D imaging mode. Examples of the noninvasive study method have been made possible through development of ECT.
mesh_terms: D001859:Bone Neoplasms / Q000000981:diagnostic imaging; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation; D005461:Fluorine; D005710:Gallium Radioisotopes; D006689:Hodgkin Disease / Q000000981:diagnostic imaging; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000000981:diagnostic imaging; D008875:Middle Aged; D009590:Nitrogen Radioisotopes; D011868:Radioisotopes; D011877:Radionuclide Imaging / Q000295:instrumentation*; D014054:Tomography / Q000295:instrumentation*
chemical_list: D002250:Carbon Radioisotopes; D005710:Gallium Radioisotopes; D009590:Nitrogen Radioisotopes; D011868:Radioisotopes; D005461:Fluorine