The new general photography system is composed of overhang of SX-YB2 departed from the mainframe of HITACHI Digital Fluoroscpic(model 110XF),topmanagement system of FSK302-1 and FSB302-1 and leveled adiogaphy system of F78-III.The filament heater circuit,rotating anode startup and running circui and X-ray produce circuit are mainly changed,and some circuits in power and filament heat are added.

Objective To analyze the CT and MRI features of primary central nervous system lymphoma ( PCNSL) and improve the accuracy of MRI diagnosis.Methods MRI features of 13 cases with PCNSL confirmed by pathology were retrospectively analyzed.All the cases were accepted MRI plain scanning and enhanced scanning. Tumor location, tumor size, signal intensity, enhancement characteristics, age distribution, cystic changes and the presence of calcification and intratumoral hemorrhage were assessed.Results Single lesion was found in 5 cases,and multiple lesions were found in 8 cases.Supra-tentorial lesions were found in 11 cases,the lesions involved both supra and infra tentorial were found in two cases.18 lesions located in deep-brain tissues,such as the thalamus,basal gan-glia,corpus callosum,midbrain and pons.7 lesions located at the surface of the brain,such as the temporal lobe,fron-tal lobe,occipital lobe and parietal lobe.The PCNSLs were found varied shapes in MRI,17 PCNSLs manifested irregu-lar shape,5 PCNSLs manifested round or ovoid shape,3 manifested butterfly shape.The average size of these lesions was 4.8cm.The PCNSLs manifested uniform or low T1 WI signal,uniform or slight high T2 WI signal,slight high or high signal on FLAIR,and slight high signal on DWI.11 cases manifested uniform signal and 2 cases manifested non-uniform signal.Different degrees of edema and mass effect were found combined with the lesions.The CT scan showed 6 cases were slighted high density,4 cases were equal density,3 cases were showed low density.Cystic chan-ges and calcifications were not found.In all cases,significant homogeneous enhancement was shown in 3 cases,moder-ate heterogeneous enhancement was shown in 1 case and mild enhancement was shown in 1 case.In multifocal dis-ease,significant homogeneous enhancement was shown in 14 cases,moderate heterogeneous enhancement was shown in 6 cases and mild enhancement was not shown.Conclusion The CT and MRI features of PCNSL of immunocompe-tent patients are always uniformity, whether T1 WIor T2 WI, while of immunodeficiency patients are complicated, all these features are helpful to make correct diagnosis.