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Physical and biological doses produced from neutron capture in a 235 U foil
Author(s) -
Liu Hungyuan B.,
Brugger Robert M.,
Laster Brenda H.,
Greenberg Dennis D.,
Gordon Chris R.,
Warkentien Lynne S.
Publication year - 1995
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597546
Subject(s) - dosimetry , foil method , nuclear physics , neutron , physics , radiochemistry , nuclear medicine , medical physics , materials science , medicine , chemistry , composite material
As a follow‐on study to the feasibility of neutron capture therapy (NCT) with 235 U brachytherapy seeds, physical doses were calculated and measured for the radiation from a 235 U foil in a lucite phantom which was irradiated at the epithermal neutron irradiation port of the Brookhaven Medical Research Reactor. In addition, cell survival experiments were performed to obtain the relative biological effectiveness (RBE) for the neutron part of the radiation. The calculated absorbed doses agree with the measured ones. From cell survival experiments, it is deduced that the fission neutrons from the 235 U foil have a RBE of 3.0 while the fast neutrons in the beam have a RBE of 3.8. Also observed is that, with the cells 7 mm from the foil, a significant amount of absorbed dose comes from the β rays of 235 U fission events. This absorbed dose from β rays is a significant addition to the therapeutic dose. Due to the limited ranges of β rays in tissue, this absorbed dose is restricted to the vicinity of the foil. This is the first demonstration of β rays as part of NCT.