Dosimetric comparison of six epithermal neutron beams using an ellipsoidal water phantom

The physical performance of the epithermal neutron beams used by the principal NCT facilities to accrue clinical results in Western Europe and USA were assessed under equivalent irradiation conditions. Using a common dosimetry method variations in the separate dose components for the different facilities were quantified both in-air and in an ellipsoidal phantom. Figures of merit were generated to assess beam performance under realistic conditions akin to therapy. The overall performance characteristics of the different beams are generally not markedly different except for the available dose rates, which vary by a factor greater than six.