A microdosimetric characterization of a cyclotron-produced therapeutic neutron beam.
The therapeutic neutron beam of the Cyclotron Corporation's CP-42 negative-ion cyclotron is generated by protons of 42 MeV bombarding a thin beryllium target. Microdosimetric measurements were made for this neutron beam in a full-scatter water phantom at nine positions inside and outside the useful beam. The lineal energy distribution and the variations of dose-mean, frequency-mean, and saturated lineal energy are compared for these positions. The dose fraction due to gamma rays is also calculated at each of these positions, based upon previously published techniques. A theoretical relative biologic effectiveness, based upon the dual radiation action model of Kellerer and Rossi [Curr. Top. Radiat. Res. 8, 85 (1972)] is also shown for the positions of measurement.
Department of Radiation Physics, University of Texas M.D. Anderson Hospital and Tumor Institute, Houston 77030.
P M
PM
Stafford
J L
JL
Horton
P R
PR
Almond
D005720:Gamma Rays; D006801:Humans; D009502:Neutrons; D010315:Particle Accelerators; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage