5 C3F8: Perfluoropropane
, PC: Photocoagulation, TA: Triamcinolone acetonide, Cryo: Cryotherapy, PPV: Pars plana vitrectomy, Si: Silicone, HM: Hand motions, CF: Counting fingers
When porphyrin lipid-shell microbubbles containing perfluoropropane
gas are bombarded by low-frequency ultrasound energy, they burst and release nanoparticles as small as five nanometres in diameter that can readily travel into a tumour's deepest recesses.
Two agents containing perfluoropropane
are currently approved in the United States for use in cardiology: Optison[R] (Mallinckrodt Inc.
which makes tiny, gas-filled bubbles by enclosing minute quantities of perfluoropropane
in fatty shells that are similar to cell membranes in humans.
5,855,865 to MBI, which describes methods for making protein microspheres encapsulating perfluorocarbon gases, such as perfluoropropane
, by ultrasonic or mechanical cavitation in the absence of oxygen.
However, most surgeons would prefer air and a nonexpansile concentration of sulfur hexafluoride (15%-20% SF6) first, reserving perfluoropropane
(12%-14% C3F8) that has longer resorption time for cases that fail to reattach with the other two gases, or those detached for a prolonged period of time.