United States Patent ( 19 ) Unger ( 54 ) LOW DENSITY MICROSPHERES AND THER USE AS CONTRASTAGENTS FOR COMPUTED TOMOGRAPHY 76 Inventor :

(22 Filed: Apr. 5, 1991 51) Int, Cl........................... A61B5/05; A61B6/03; C08J 9/16 52 U.S. C. ................................. 128/653.4; 128/654; 424/489; 424/501; 52.1/54; 521/56; 521/59; 521/74; 521/78; 521/136; 521/137; 521/142; 521/145; 521/146; 521/149; 521/150; 526/72; 526/313; 526/317.1; 526/320,528/87;528/102 58) Field of Search ....................... 521/54, 56, 59,74, 521/78, 136, 137, 145, 142, 146, 147, 149, 150; 526/320, 72, 194, 313,317.1; 528/87, 102; 128/653.4, 654; 424/489, 501