Granted Patent
Utility
US 5,281,408 · App. 07/980,594
Low density microspheres and their use as contrast agents for computed tomography
Inventor:
Evan C. Unger
Patented Case
View Patent ↗
Granted: Jan 25, 1994
Filed: Jan 19, 1993
Inventor
Evan C. Unger
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.