An instant dose obtainable in situ calorimeter

The development of a computer-linked water calorimeter is described. The advantages of this system are twofold: (i) instant dose determination is possible; and (ii) the calorimeter operation is much simpler than conventional null balance techniques. The entire calorimeter measurement procedure from the set-up to the dose determination for 10 runs was finished in approximately 2 1/2 h. A smaller calorimeter which could be kept in the treatment room for equilibrium, should permit further reduction of the time. The use of a smaller, portable computer would allow local data taking and analysis, eliminating the need for modems, phone lines and long cables. This would lead to a completely self-contained set-up at the treatment room. Although the technique is described for a polystyrene-water calorimeter, it should be equally applicable for a water calorimeter as well as a conventional isolated calorimeter. (author)