The dosimetric impact of prostate rotations during electromagnetically guided external-beam radiation therapy.
Int J Radiat Oncol Biol Phys
; 85(1): 230-6, 2013 Jan 01.
Article
en En
| MEDLINE
| ID: mdl-22554583
ABSTRACT
PURPOSE:
To study the impact of daily rotations and translations of the prostate on dosimetric coverage during radiation therapy (RT). METHODS AND MATERIALS Real-time tracking data for 26 patients were obtained during RT. Intensity modulated radiation therapy plans meeting RTOG 0126 dosimetric criteria were created with 0-, 2-, 3-, and 5-mm planning target volume (PTV) margins. Daily translations and rotations were used to reconstruct prostate delivered dose from the planned dose. D95 and V79 were computed from the delivered dose to evaluate target coverage and the adequacy of PTV margins. Prostate equivalent rotation is a new metric introduced in this study to quantify prostate rotations by accounting for prostate shape and length of rotational lever arm.RESULTS:
Large variations in prostate delivered dose were seen among patients. Adequate target coverage was met in 39%, 65%, and 84% of the patients for plans with 2-, 3-, and 5-mm PTV margins, respectively. Although no correlations between prostate delivered dose and daily rotations were seen, the data showed a clear correlation with prostate equivalent rotation.CONCLUSIONS:
Prostate rotations during RT could cause significant underdosing even if daily translations were managed. These rotations should be managed with rotational tolerances based on prostate equivalent rotations.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Próstata
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Neoplasias de la Próstata
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Dosificación Radioterapéutica
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Campos Electromagnéticos
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Radioterapia de Intensidad Modulada
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Movimiento
Límite:
Humans
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Male
Idioma:
En
Revista:
Int J Radiat Oncol Biol Phys
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos