[The physical and technical outlook for neutron therapy in Germany]

All five fast neutron therapy centres in Germany use low energy cyclotrons or neutron generators and are, therefore, at the low energy end of the 21 neutron therapy facilities presently in use worldwide. The depth dose characteristics are worse than for 60Co gamma rays, the absorbed dose rate is too low and the treatment is technically restricted because of the lack of those modern features like multileaf collimators and full gantry rotation that are available with modern linear accelerators. A survey of the statistical and methodical data on the neutron treatment in Germany is presented. To avoid masking the potential biological benefits of high LET neutron irradiation by the use of suboptimal equipment and to utilise the real therapeutical benefit for specific tumor types, the German neutron therapy centres urgently need modernization of their outdated facilities. Specific recommendations of how to meet the requirements of modern neutron therapy are given.