Effects of internal and external scatter on the build-up characteristics of Monte Carlo calculated absorbed dose for electron irradiation.
Australas Phys Eng Sci Med
; 28(3): 165-71, 2005 Sep.
Article
en En
| MEDLINE
| ID: mdl-16250470
ABSTRACT
The effects of internal and external scatter on surface, build-up and depth dose characteristics simulated by Monte Carlo code EGSnrc for varying field size and SSD for a 10 MeV monoenergetic electron beam with and without an accelerator model are extensively studied in this paper. In particular, sub-millimetre surface PDD was investigated. The percentage depth doses affected significantly by the external scatter show a larger build-up dose. A forward shifted Dmax depth and a sharper fall-off region compared to PDDs with only internal scatter considered. The surface dose with both internal and external scatter shows a marked decrease at 110 cm SSD, and then slight further changes with the increasing SSD since few external scattered particles from accelerator model can reach the phantom for large SSDs. The sharp PDD increase for the 5 cm x 5 cm field compared to other fields seen when only internal scatter is considered is significantly less when external scatter is also present. The effect of external scatter on surface PDD is more pronounced for large fields than small fields (5 cm x 5 cm field).
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Radiometría
/
Algoritmos
/
Planificación de la Radioterapia Asistida por Computador
/
Artefactos
/
Radioterapia Conformacional
/
Electrones
/
Modelos Biológicos
Tipo de estudio:
Diagnostic_studies
/
Health_economic_evaluation
/
Prognostic_studies
/
Risk_factors_studies
Límite:
Humans
Idioma:
En
Revista:
Australas Phys Eng Sci Med
Año:
2005
Tipo del documento:
Article
País de afiliación:
China