Patent ID: 8366657

Claim:
A high-pressure fluid injection system for targeted delivery of fluid to a treatment site within a patient, the injection system comprising: a rechargeable injection chamber comprising a proximal end, a distal end, and an internal opening extending from the proximal end to the distal end; a plunger slideably engaged with the internal opening of the injection chamber; a first sealing member and a second sealing member, both of which are operatively engaged with the plunger, wherein a distance that the first sealing member is positioned from a distal end of the plunger is smaller than a distance that the second sealing member is spaced from the distal end of the plunger; an injection tube extending from the distal end of the injection chamber and in fluidic communication with the internal opening of the injection chamber; and a check valve between the proximal and distal ends of the injection chamber, wherein the internal opening comprises a first zone adjacent to the check valve and having a first diameter, and a second zone proximal to the first zone and having a second diameter that is larger than the first diameter, and wherein the first sealing member is spaced from an inner wall surface of the second zone when the first and second sealing members are positioned in the second zone.