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The purpose of this report is to present some of the special radiological problems which arise when a nuclear reactor or atomic pile is used in medical research and experimental radiation therapy. While there are many and various ways in which this new tool can be used, the principal emphasis here will be toward the means and the devices which are utilized in order to control the energy spectrum of the external neutron stream and to direct it selectively to the treatment site. It has become possible to investigate these problems under practical conditions of use now that a nuclear reactor has been built expressly for and as an integral part of a Medical Research Center (1). Figure 1 shows the general external aspect of the Medical Research Center at Brookhaven National Laboratory, with the reactor housed in the cylindrical building in the background. The initial exploratory phase of its operation has turned up the acute problem of extracting from the machine the kinds and the numbers of neutrons required ...

The case of a girl who was born with a large retroauricular mass diagnosed clinically as hemangioma is presented. It responded well to x-ray therapy. When she was 11 years old, a sarcoma was removed from the cerebellum. No evidence could be found that the sarcoma had originated from the retroauricular tumor. After the use of nitrogen mustard locally and three courses of x-ray therapy to the tumor over a period of 91/2 months with a total radiation dose of approximately 7953 r the patient was growing moribund. During 4 neutron-capture treatments, which were directed chiefly toward the suboccipital region, striking improvement occurred-to such an extent that the patient was able for a time to sit up in a wheelchair and converse. As a result of the therapy, all tumor which had spread suboccipitally and into the neck vanished, as did also virtually all tumor in the dorsal third of the cerebellum, the region receiving the largest concentration of thermal neutrons. In the middle third of the cerebellum large and small tumor aggregates, some of them calcified, were necrotic and were walled off by hyperplastic connective tissue. In the ventral third of the cerebellum, in a region presumably out ofmore » the range of an effective concentration of thermal neutrons, the tumor grew unimpeded. Evidence indicated that the sarcoma in this case originated in the vascular sheath, chiefly about vessels in the granular layer of the cerebellum. Life was prolonged approximately 8 months by the neutron-capture therapy. (auth)« less

During the past several years at the Brookhaven National Laboratory the experimental procedure of neutron capture therapy of intracranial neoplasms has been and is continuing to be investigated, utilizing a nuclear reactor as a neutron source. 1-5, 8,9 In neutron capture therapy there are two main components of the therapeutic system—the capture, or target atom, and the thermal neutron, or triggering component. As a result of thermal neutron capture, an atomic transformation occurs with release of energy. When the target atom is boron-10, the thermal neutron capture triggers an immediate disintegration of the boron-10 into an energetic lithium-7 atom and an energetic alpha particle with a modest gamma ray emission totaling in all an energy release of 2.4 mev. The restricted distribution of the energy release to a volume of one average cell provides a selectivity of action that in principle will affect one cell suitably primed and loaded while