Clinical trials with new radiation modalities.

I would suggest that the investigation of a new clinical modality involves a major commitment by the whole clinical group of the department involved and not just by the people chosen to be the primary investigators. As a base for comparison, it requires a detailed knowledge of the results and sites of failures and complications of the therapy used by that department. To make adequate relative biologic effect studies for the new modality, suitable comparative, quantitative tissue and tumor assays have to be done with photons and these could be done and established before the new modality came on line. For the Phase III trial, which is usually considered a randomized comparative trial, it can be argued (and a method is proposed) for the use of a non-randomized study to make the maximum use of patients coming to the centre.