Intrafraction motion of the prostate during an IMRT session: a fiducial-based 3D measurement with Cone-beam CT.
Radiat Oncol
; 3: 37, 2008 Nov 05.
Article
en En
| MEDLINE
| ID: mdl-18986517
ABSTRACT
BACKGROUND:
Image-guidance systems allow accurate interfractional repositioning of IMRT treatments, however, these may require up to 15 minutes. Therefore intrafraction motion might have an impact on treatment precision. 3D geometric data regarding intrafraction prostate motion are rare; we therefore assessed its magnitude with pre- and post-treatment fiducial-based imaging with cone-beam-CT (CBCT).METHODS:
39 IMRT fractions in 5 prostate cancer patients after 125I-seed implantation were evaluated. Patient position was corrected based on the 125I-seeds after pre-treatment CBCT. Immediately after treatment delivery, a second CBCT was performed. Differences in bone- and fiducial position were measured by seed-based grey-value matching.RESULTS:
Fraction time was 13.6 +/- 1.6 minutes. Median overall displacement vector length of 125I-seeds was 3 mm (M = 3 mm, Sigma = 0.9 mm, sigma = 1.7 mm; M group systematic error, Sigma SD of systematic error, sigma SD of random error). Median displacement vector of bony structures was 1.84 mm (M = 2.9 mm, Sigma = 1 mm, sigma = 3.2 mm). Median displacement vector length of the prostate relative to bony structures was 1.9 mm (M = 3 mm, Sigma = 1.3 mm, sigma = 2.6 mm).CONCLUSION:
a) Overall displacement vector length during an IMRT session is < 3 mm.b) Positioning devices reducing intrafraction bony displacements can further reduce overall intrafraction motion.c) Intrafraction prostate motion relative to bony structures is < 2 mm and may be further reduced by institutional protocols and reduction of IMRT duration.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Próstata
/
Radioterapia de Intensidad Modulada
/
Tomografía Computarizada de Haz Cónico
Tipo de estudio:
Guideline
Límite:
Humans
/
Male
Idioma:
En
Revista:
Radiat Oncol
Asunto de la revista:
NEOPLASIAS
/
RADIOTERAPIA
Año:
2008
Tipo del documento:
Article
País de afiliación:
Alemania