Various CT-scanners have been designed and built at the University of Rome "La Sapienza" since 1980, also in cooperation with the Research Center EMBRAPA-NPDIA, Sao Carlos, S.P., Brazil, and with the financial support of the European Communities. These CT-scanners were mainly devoted to non-medical applications (soil physics, archaeometry, industrial applications) or to test new imaging methods (differential tomography, microtomography, XRF-tomography and so on). Besides the first CT-scanner, constructed in 1980, and the Sao Carlos scanner, constructed in 1986, both characterized by an Am241 source emitting 60keV radiation, and by non-sophisticated mechanics, the more recent scanners consist of: -a X-ray tube of 160kV and 10mA for tomographs of largeobjects (approximately from 1cm to 40cm diameter) and a X-ray tube of 50kV and 30mA for tomogra[hs of small objects or microtomographs (approximately from few mm to 1cm)%-a sophisticated translation-rotation system, able to make movements with micrometer precision%-a single X-ray detector, such as Nal(TI)-scintillator, or a Si-PIN photodiode, or a HpGe for special applications where a high energy resolution is required, or -a multidetector system, such as an image intensifier for images of large objects, or a photodiode-array, for microtomography%various types of PC's, of the 286 and 486 type, for both driving the mechanics, andcollecting the transmission data, and for image reconstruction and filtering...