[Constant infusion system of 15O labeled-water]

The quantitative measurement of regional blood flow and regional extravascular lung water, called for a design of 15O labeled water production and administration under continuous and constant flow. In our search for simple methodology, suitable for clinical routine facilities, two remote-controlled systems were designed and their applicability for continuous and constant infusion of H215O were tested. In system (A), H215O was prepared from C15O2 based on the fast exchange reaction between carbon dioxide and carbonic acid. In the system (B), the reaction of 15O2 with H2 using palladium as a catalyst was adopted. In the both systems, the radioactivity level of the infusate was kept constant by using a buffer reservoir. Clinical applicability of both fully automated systems for the production of sterile H215O at a continuous and constant rate was discussed. Namely, system (A), being very simple seems more suitable for any closely located facility but system (B) is more suited for the production of higher radioactivity.