Gantry angle dependence in IMRT pre-treatment patient-specific quality controls.
Phys Med
; 29(2): 204-7, 2013 Mar.
Article
en En
| MEDLINE
| ID: mdl-22281096
ABSTRACT
Intensity Modulated Radiation Therapy (IMRT) is a complex treatment modality that requires pre-treatment patient-specific quality control (QC) in order to assess a correct treatment delivery. The aim of this work is to investigate pre-treatment patient-specific per-field QCs performed with an on-board EPID at the gantry angle of 0° and at the treatment ones, and to asses if measurements executed at 0° are able to guarantee a correct treatment. Ten patients with prostate cancer were evaluated. Two "verification" plans were created for each patient in order to calculate the dose at the EPID surface one with all fields positioned at 0° and one with all fields at the actual treatment angles. EPID's mechanical shifts due to gravity effects were always taken into account and corrected. 0 and no-0 plans were compared using a gamma-index method (3%, 3 mm). The gamma index was found dependent on gantry angles but the difference between 0 and no-0 samples was small (-0.3% mean value) and the criteria of acceptability of the gamma method was always satisfied for every field delivered at angles different from 0. Therefore patient-specific pre-treatment QCs should be done at treatments angles, but, if periodical quality assurance is performed on dynamic MLC for different gantry angles, this requirement was shown not strictly mandatory and pre-treatment IMRTQC can be reasonably executed at 0° angles too.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Planificación de la Radioterapia Asistida por Computador
/
Radioterapia de Intensidad Modulada
/
Medicina de Precisión
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Phys Med
Asunto de la revista:
BIOFISICA
/
BIOLOGIA
/
MEDICINA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Italia