(19)

(11)

EP 0 466 828 A1

(12)

(43) Date of publication: 22.01.1992 Bulletin 1992/04 (21) Application number: 90906721.0 (22) Date of filing: 09.04.1990

(51) International Patent Classification (IPC):  A61B 5/ 00( . ) (86) International application number: PCT/US1990/001914 (87) International publication number: WO 1990/012536 (01.11.1990 Gazette 1990/25)

(84) Designated Contracting States: CH DE FR GB IT LI (30) Priority: 14.04.1989 US 19890337935 (71) Applicant: MASSACHUSETTS INSTITUTE OF TECHNOLOGY Cambridge, MA 02139 (US)	(72) Inventors: RICHARDS-KORTUM, Rebecca Cambridge, MA 02142 (US) TONG, Lucene Hayward, CA 94545 (US) FELD, Michael, S. Waban, MA 02168 (US) (74) Representative: Holdcroft, James Gerald, Dr.  Graham Watt & Co. 3 Gray's Inn Square London WC1R 5AH London WC1R 5AH (GB)