A METHOD FOR ASSESSING CATHETER PATENCY IN IMPLANTED PUMPS FOR LONG-TERM INTRAPERITONEAL INSULIN DELIVERY

Catheter complications are a common problem during long-term insulin t herapy with implanted pumps. The purpose of this study was to test the feasibility of imaging intraperitoneal catheters with technetium (Tc) 99m in implantable devices for insulin delivery. Testing physical sta bility of an insulin/Tc 99 mixture did not show formation of insulin a ggregates during a period up to 48 h on a rotating wheel. Five hundred microCurie (equal to 18 MBq) of Tc 99m were injected in the flush por t of a pump for intraperitoneal insulin delivery implanted in patients with type I (insulin dependent) diabetes mellitus, and gamma camera i mages were obtained for 30 min. In patent catheters the tracer rapidly imaged the whole length of the catheter while in occluded catheters t he tracer remained in the flush port, imaging only the portion of the catheter before the occlusion. In patent catheters in which insulin ab sorption was impaired, the tracer rapidly imaged the whole length of t he catheter, but its removal from the peritoneum was delayed. Tc 99m i maging of intraperitoneal catheters for insulin delivery can be used t o assess catheter patency and impaired delivery into the peritoneal ca vity.