Evaluating positional accuracy using megavoltage cone-beam computed tomography for IMRT with head-and-neck cancer.
J Radiat Res
; 55(3): 568-74, 2014 May.
Article
en En
| MEDLINE
| ID: mdl-24449713
Accurate dose delivery is essential for the success of intensity-modulated radiation therapy (IMRT) for patients with head-and-neck (HN) cancer. Reproducibility of IMRT dose delivery to HN regions can be critically influenced by treatment-related changes in body contours. Moreover, some set-up margins may not be adaptable to positional uncertainties of HN structures at every treatment. To obtain evidence for appropriate set-up margins in various head and neck areas, we prospectively evaluated positional deviation (δ values) of four bony landmarks (i.e. the clivus and occipital protuberance for the head region, and the mental protuberance and C5 for the neck region) using megavoltage cone-beam computed tomography during a treatment course. Over 800 δ values were analyzed in each translational direction. Positional uncertainties for HN cancer patients undergoing IMRT were evaluated relative to the body mass index. Low positional accuracy was observed for the neck region compared with the head region. For the head region, most of the δ was distributed within ± 5 mm, and use of the current set-up margin was appropriate. However, the δ values for the neck region were within ± 8 mm. Especially for overweight patients, a few millimeters needed to be added to give an adequate set-up margin. For accurate dose delivery to targets and to avoid excess exposure to normal tissues, we recommend that the positional verification process be performed before every treatment.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Imagenología Tridimensional
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Radioterapia de Intensidad Modulada
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Tomografía Computarizada de Haz Cónico
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Posicionamiento del Paciente
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Radioterapia Guiada por Imagen
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Neoplasias de Cabeza y Cuello
Tipo de estudio:
Diagnostic_studies
Límite:
Adolescent
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Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
J Radiat Res
Año:
2014
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Reino Unido