Experimental D-T neutron generator by Philips, in use from 1975 to 1981.
In 1975, the Philips experimental neutron generator comes into use at the Netherlands Cancer Institute (NKI) in megavoltage room 7 (current name A2). This device produces neutron radiation with an energy of 14 MeV originating from the collision of deuterium (D), accelerated to 250 kV, and tritium (T). The neutron output is 1012 neutrons/s.
This neutron generator resembles in many aspects the generator used by Daniel den Hoed in 1936 in the Philips NatLab to perform radiobiological research with neutrons. A new feature in the design is that the accelerator tube has been sealed in the factory and contains a fixed amount of deuterium and tritium. The lifetime of the tube is therefore limited and the tube has to be replaced regularly. The tube and technical systems of the generator are mounted on a rotateble gantry, thus allowing patient treatments from all directions. The gantry has been delivered by a Swiss vendor (Brown Boveri Company, BBC). It is the same gantry as used for the 40 MeV Betatron by BBC.
Control panel of the neutron generator, with radiation therapist Mariëlle Stuyt
Radiation oncologists are interested in using fast neutrons clinically because, for the same dose, they have a more pronounced biological effect than X-rays. This is related to the shorter distance travelled by neutrons to deposit their energy in human tissue. Also the radiobiological effect on tissues having a poor blood supply is larger compared to of orthovoltage X-rays or megavoltage photons. In theory therefore, fast neutrons are more effective than photons in producing biological damage and less dependent on factors affecting radiation sensitivity.
Automatic change of field size collimators through a floor shutter.
The collimators become radioactive by irradiating them with neutrons. After some storage time in the basement, the radioactivity is reduced sufficiently to use them again.
The neutron tube is exchanged.
The red container was used for the transport of the tubes from the factory of Philips in Eindhoven to the NKI and vice versa.
The experimental treatments take place between 1975 and 1981. Radiation oncologist Jan Battermann and physicist Ben Mijnheer demonstrate in a 4-year study that the neutron treatments resulted only in minor improvement or no improvement at all compared to megavoltage photon beam treatment. For some tumour sites the neutron results were even worse. Due to these disappointing results, combined with the high costs and efforts, the experiment was stopped.
At the position of the neutron generator a 14 MeV linear electron accelerator is installed (8 MV photon and 6-14 MeV electron beams).
In 1979, Jan Battermann receives the Wertheim Salomonson medal for his study of the clinical possibilities of neutron irradiation with the D-T generator of Philips in the NKI. After Daniel den Hoed (1933) and Betty Levie (1940) he is the third radiation oncologist from the NKI to receive this award.
Professor Jan J. Battermann.
Jan Battermann was trained as radiation oncologist in the Netherlands Cancer Institute by Professor Klaas Breur. In 1976 he finishes his training and is appointed as staff member with the main task of clinical supervision of the neutron therapy project.
After the accomplishment of the neutron project in 1981 he receives his doctorate with a thesis entitled "Clinical applications of fast neutrons, the Amsterdam experience" 
Until 1986 he works as radiation oncologist in the NK-AVL. In 1986 Jan Battermann is appointed professor in radiation oncology at the University of Utrecht, and becomes head of the Radiotherapy Department of the teaching hospital in Utrecht (Academisch Ziekenhuis Utrecht, AZU).
Ben Mijnheer (physicist, right) and Peter Visser (physics engineer, left) are responsible for the physics and technical aspects of the neutron therapy project.