A comparison of dose and set-up accuracy between flexed and extended neck positions in Helical Tomotherapy of nasopharyngeal carcinoma.
Med Dosim
; 45(3): 235-240, 2020.
Article
em En
| MEDLINE
| ID: mdl-31982242
ABSTRACT
Nasopharyngeal carcinoma (NPC) patients treated with Helical Tomotherapy (HT) are commonly set up in an extended neck (EN) or a flexed neck (FN) position. This study investigated the dosimetric and set-up accuracy differences between these 2 set-up positions. Twenty NPC patients treated with HT from each set-up position were retrospectively recruited. HT plans were computed using the same target prescription and organs at risks (OARs) constraints for both set-up positions. The doses parameters of the target volumes and OARs were assessed. Daily megavoltage CT images were retrieved to obtain the set-up errors at 4th (C4) and 7th (C7) cervical levels. The mean values of these parameters were compared between the 2 set-up positions. The dose to NP target in FN group was more conformal than EN group, while the conformity of the neck targets in FN group were significantly lower. For the OARs, the temporal lobe, cerebellum, and hippocampus in FN group received significantly lower doses than the EN. However, the optic structures, brain stem, spinal cord, and parotid glands received higher doses in FN group. The systematic errors at C4 and C7 levels in FN group were larger in all translational directions except the ML direction at C7 level. With regard to radiotherapy of NPC patient using helical tomotherapy, FN position reduced doses to intracranial structures but increased doses to optic structures and other structures when compared with the EN position. In terms of set-up accuracy at the neck region, EN position was relatively better.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Postura
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Neoplasias Nasofaríngeas
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Radioterapia de Intensidade Modulada
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Posicionamento do Paciente
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Carcinoma Nasofaríngeo
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Pescoço
Tipo de estudo:
Observational_studies
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Risk_factors_studies
Limite:
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:
Med Dosim
Assunto da revista:
RADIOTERAPIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Hong Kong