TI: Regional Oxygenation and Radiotherapy: A Study of the Degradation of Infused Hydrogen Peroxide I. Infusate mixing DT: December 7, 1970 AU: James I. MacNaughton SO: Int. J. Radiat. Bilog., 1971, Vol. 19, No. 5, pp 405-413 AB: To ascribe the therapeutic benefits following simultaneous peroxide infusion and radiotherapy to the oxygen effect is to assume that the infused peroxide breaks down very rapidly. The literature gives disparate values for the rate of decomposition of peroxide, one supporting the oxygen effect, the other consonant with a "peroxide effect". In vitro experiments with model systems simulating in vivo flow conditions have been used to examine the mixing of infusate in a stream of flowing fluid. Mixing has been shown to be imperfect even after one second has elapsed. The effect of imperfect mixing on the decomposition rate has been discussed. Infusion through an epidural cannula produces little or no turbulence to assist mixing. It was observed that two reactive chemical species (peroxide and permanganate) can coexist in stream form within a tube. Similar behaviour between blood catalase and infused peroxide may also be possible. The decomposition of peroxide infused into flowing blood is examined directly in the following paper (Oxy94.txt).