Photon dose perturbations due to small inhomogeneities
- 1 January 1987
- journal article
- research article
- Published by Wiley in Medical Physics
- Vol. 14 (1), 78-83
- https://doi.org/10.1118/1.596106
Abstract
An apparatus capable of measuring small fractional changes in ionization current has been used to study the effect of small inhomogeneities on photon dose in water. Small ring-shaped inhomogeneities were introduced into a water phantom and measurements have been made for 4-, 6-, and 18-MV x-rays. The results show (1) beyond the range of secondary electrons, the dose perturbation is basically a photon transport phenomenon which becomes less important as the beam energy increases; (2) within the range of secondary electrons, dose perturbation also involves electron transport, which has a strong dependence on atomic number and could result in a substantially large effect on dose deposition.Keywords
Funding Information
- National Cancer Institute (R01-CA41574-01)