Dosimetry of small electron fields shaped by lead.
Australas Phys Eng Sci Med
; 26(3): 119-24, 2003 Sep.
Article
em En
| MEDLINE
| ID: mdl-14626851
ABSTRACT
Electron radiotherapy fields are commonly used to treat superficial cancers. Field shaping can be achieved by placing lead on the patient surface to minimise the dose to surrounding areas. However, significant dosimetry changes under high density material edges for electron fields have been reported in the literature. This project evaluated the dosimetry of small dimension electron fields shaped with lead placed on the surface. Comparisons were made between circular lead cutouts placed on the skin and low melting point alloy cutouts placed in an applicator. Depth doses, profiles and output factors were measured using a diode detector in a water phantom. Film was also used to determine surface dose delivered when the lead cutouts were placed on the surface. Minimal differences were observed between the different setups for the depth dose curves, although significant differences were seen in the penumbra and the surface doses. The penumbra is smaller for the lead cutouts placed on the surface, however, significant dose increases at the edge of the field were observed for larger fields and energies; this may result in undesirable clinical effects.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radiometria
/
Planejamento da Radioterapia Assistida por Computador
/
Radioterapia de Alta Energia
/
Elétrons
/
Chumbo
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
Limite:
Humans
Idioma:
En
Revista:
Australas Phys Eng Sci Med
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Austrália