Field-size dependence of doses of therapeutic carbon beams.
Med Phys
; 34(10): 4016-22, 2007 Oct.
Article
em En
| MEDLINE
| ID: mdl-17985647
ABSTRACT
To estimate the physical dose at the center of spread-out Bragg peaks (SOBP) for various conditions of the irradiation system, a semiempirical approach was applied. The dose at the center of the SOBP depends on the field size because of large-angle scattering particles in the water phantom. For a small field of 5 x 5 cm2, the dose was reduced to 99.2%, 97.5%, and 96.5% of the dose used for the open field in the case of 290, 350, and 400 MeV/n carbon beams, respectively. Based on the three-Gaussian form of the lateral dose distributions of the carbon pencil beam, which has previously been shown to be effective for describing scattered carbon beams, we reconstructed the dose distributions of the SOBP beam. The reconstructed lateral dose distribution reproduced the measured lateral dose distributions very well. The field-size dependencies calculated using the reconstructed lateral dose distribution of the therapeutic carbon beam agreed with the measured dose dependency very well. The reconstructed beam was also used for irregularly shaped fields. The resultant dose distribution agreed with the measured dose distribution. The reconstructed beams were found to be applicable to the treatment-planning system.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radiometria
/
Dosagem Radioterapêutica
/
Planejamento da Radioterapia Assistida por Computador
/
Carbono
/
Radioterapia de Alta Energia
Tipo de estudo:
Risk_factors_studies
Idioma:
En
Revista:
Med Phys
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Japão