Practical Requirements for the Treatment of Patients with Cancer

There is great world-wide interest in the possibilities of fast neutron therapy of cancer. In order to meet the increasing demands for fast neutrons to treat patients, cyclotrons, constructed for other purposes, are being adapted for clinical work. Many however, are essentially unsuitable for this purpose. Other cyclotrons which are being constructed are technically inferior to the modern megavoltage X-ray or ?-ray apparatus routinely available in Radiotherapy Departments. There is, therefore, a great risk that misleading information will result from clinical studies using such equipment since this could reflect more the inadequacy of the delivery of neutrons to the tumour than the effects of neutrons themselves. Six factors are proposed which must be included in the production of a neutron machine in order that patients may be treated in a manner comparable to that using photons from the megavoltage machines now in regular use throughout the world.