Dose optimization for the MRI-accelerator: IMRT in the presence of a magnetic field.
Phys Med Biol
; 52(23): 7045-54, 2007 Dec 07.
Article
en En
| MEDLINE
| ID: mdl-18029992
A combined system of a 6 MV linear accelerator and a 1.5 T MRI scanner is currently being developed. In this system, the patient will be irradiated in the presence of a 1.5 T magnetic field. This causes a strong dose increase at tissue-air interfaces. Around air cavities in the patient, these effects may become problematic. Homogeneous dose distributions can be obtained around regularly shaped symmetrical cavities using opposing beams. However, for more irregularly shaped cavities this approach may not be sufficient. This study will investigate whether IMRT can be used to cope with magnetic field dose effects, in particular for target volumes adjacent to irregularly shaped air cavities. Therefore, an inverse treatment planning approach has been designed based on pre-calculated beamlet dose distribution kernels. Using this approach, optimized dose distributions were calculated for B = 1.5 T and for B = 0 T. Investigated target sites include a prostate cancer, a laryngeal cancer and an oropharyngeal cancer. Differences in the dose distribution between B = 0 and 1.5 T were minimal; only the skin dose increased for B = 1.5 T. Homogeneous dose distributions were obtained for target structures adjacent to air cavities without the use of opposing beams. These results show that a 1.5 T magnetic field does not compromise the ability to achieve desired dose distributions with IMRT.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Próstata
/
Radiometría
/
Planificación de la Radioterapia Asistida por Computador
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Imagen por Resonancia Magnética
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Radioterapia Conformacional
/
Modelos Biológicos
Tipo de estudio:
Prognostic_studies
Límite:
Humans
/
Male
Idioma:
En
Revista:
Phys Med Biol
Año:
2007
Tipo del documento:
Article
País de afiliación:
Países Bajos
Pais de publicación:
Reino Unido