A new minor surgical procedure for ascites has been devised wherein a specially designated one way pressure activated valve is implanted to create a permanent peritoneo-venous shunt. The normally closed valves opens only when the peritoneal pressure rises 3-5 cm higher than the intrathoracic venous pressure thus preventing backflow of blood and closing the valve should the venous pressure rise from the over-infusion of ascitic fluid. The procedure has been performed on 45 patients but nine were terminal at the time of surgery. Prolonged relief of ascites occurred in 28 of 37 cases.

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Tumor blood flow, measured by an isotope dilution technique, is only 2% to 15% of that of the surrounding tissue. This sluggish circulation differentiates cancer from normal tissue and forms the basis for a new therapy that entails the transfer of radiofrequency (RF) energy for heating tissues locally. The heated tissue is cooled by the circulation of blood, which carries away the heat. Impaired perfusion, as in cancers, impedes cooling. Heating by RF elevated the temperatures of animal and human cancers by 5 to 9.5 C above that of healthy tissue. The heat eradicated the animal cancers without destruction of normal tissue. Radiofrequency therapy produced tissue necrosis or substantial regression of cancer in 21 patients.

A specially devised pressure-sensitive valve forms the basis for a new peritoneo-venous shunt operation which delivers ascitic fluid continuously into the venous system. It is effective in ascites attributed to different causes. The procedure is simple and brings a long lasting relief with recovery in strength and nutrition and improved kidney function. Hepatorenal syndrome in ascites is reversed.

A description is given of a computer simulation technique which predicts the specific absorption rate (SAR) distribution within the human body resulting from the application of radiofrequency electromagnetic energy. The method uses an extension to the principle of over-relaxation of electric potentials and the basis of the simulation is a realistic three-dimensional model derived from both dielectric and anatomical data. Two of the principal means of applying radiofrequency hyperthermia, namely the use of capacitive electrodes and inductive coils, have been provided for. The accuracy of the simulation has been favourably tested using an agar split-phantom and an infrared thermograph camera. The simulations can be used to assist the design and clinical use of radiofrequency applicators, and examples are given of the application of both an inductive coil and switched capacitive electrodes to heat the thorax.