We have demonstrated in previous paper that waterjet flow enabled mucosal incision of the stomach and esophagus and submucosal saline injection and it could be used for endoscopic treatment. We developed the catheter with special nozzle and injection syringe for endoscopic use. The caliber of the nozzle decreases so gradually that any whirl of the flow is hardly produced. Therefore pressure loss can be regarded to yield by mainly fluid frictional resistance. The pressure loss of nozzle was 4.9×10^5 Pa and that of catheter with the full length of two meter was 7.5×10^5 Pa. We developed a polyethersulfon syringe with much lower compliance than polypropirene for Auto injector 120 R (Nemoto Kyorindo Co., Ltd.) which was used was waterjet generator. We measured actual jet pressure at the nozzle tip, and we found it was over 3 Mpa and enough to cut the muscularis mucosae. We think that these devices make it possible to apply weterjet technology to endoscopic therapy.
