Lateral electron equilibrium and electron contamination in measurements of head-scatter factors using miniphantoms and brass caps. Med Phys 1995 Jul;22(7):1167-70
Date
07/01/1995Pubmed ID
7565391DOI
10.1118/1.597508Scopus ID
2-s2.0-0029159832 (requires institutional sign-in at Scopus site) 93 CitationsAbstract
The head-scatter factor (Sh) can be measured with a narrow miniphantom or a metal cap provided it is completely covered by the photon beam and its lateral size is thick enough to prevent electron contamination contributions. The effects of lateral electron equilibrium (LEE) and electron contamination on the Sh values were studied. The EGS4 Monte Carlo technique was used to calculate the minimum beam radii (rLEE) required to achieve complete LEE for photon beams ranging from 60Co to 24 MV. The measurement shows that the error introduced to the Sh value due to lateral electron disequilibrium is negligible. The radii of the miniphantoms or the sidewall thicknesses of the caps can be reduced below rLEE provided they are thick enough to prevent the effect of electron contamination.
Author List
Li XA, Soubra M, Szanto J, Gerig LHMESH terms used to index this publication - Major topics in bold
Biophysical PhenomenaBiophysics
Copper
Electrons
Humans
Monte Carlo Method
Phantoms, Imaging
Radiation Dosage
Radiometry
Scattering, Radiation
Zinc