Abstract
The mean quality factor (Q̄) and the dose mean linear energy transfer [LET (L̄(d))] a few centimeters outside a neutron therapy beam have been measured using a high-pressure ionization chamber. Measurements have been carried out in air, 5 and 100 cm outside the treatment field edge on the patient plane for p(46)-Be neutrons and are compared with the results obtained at the same points with a low-pressure proportional counter (Rossi counter) and a Bonner spheres system. General agreement is found between these independent methods. The dose equivalent at 5 and 100 cm distances outside the field edge is 2% and 0.4% of the dose equivalent at the isocenter. Measurements were also performed at the same points as a function of proton energy on the Be target. Proton energies of 25-46 MeV on Be were applied. The results indicate increase in the mean quality factor at proton energies below 30 MeV.
Original language | English (US) |
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Pages (from-to) | 84-86 |
Number of pages | 3 |
Journal | Medical Physics |
Volume | 17 |
Issue number | 1 |
DOIs | |
State | Published - 1990 |
ASJC Scopus subject areas
- Biophysics