The effect of delineation method and observer variability on bladder dose-volume histograms for prostate intensity modulated radiotherapy.
Radiother Oncol
; 101(3): 479-85, 2011 Dec.
Article
em En
| MEDLINE
| ID: mdl-21864921
PURPOSE: To quantify the effect of delineation method on bladder DVH, observer variability (OV) and contouring time for prostate IMRT plans. MATERIALS AND METHODS: Planning CT scans and IMRT plans of 30 prostate cancer patients were anonymized. For 20 patients, 1 observer delineated the bladder using 9 methods. The effect of delineation method on the DVH curve, discrete dose levels and delineation time was quantified. For the 10 remaining CTs, 6 observers delineated bladder wall using 4 methods. Observer-based volume variation and intraclass correlation coefficient (ICC) were used to describe the dosimetric effects of OV. RESULTS: Manual delineation of the bladder wall (BW_m) was significantly slower than any other method (mean: 20 min vs. ≤ 13 min) and the dosimetric effect of OV was significantly larger (V70 Gy ICC: 0.78 vs. 0.98). Only volumes created using a 2.5mm contraction from the outer surface, and a method providing a consistent wall volume, showed no notable dosimetric differences from BW_m in both absolute and relative volume. CONCLUSIONS: Automatic contractions from the outer surface provide quicker, more reproducible and reasonably accurate substitutes for BW_m. The widespread use of automatic contractions to create a bladder wall volume would assist in the consistent application of IMRT dose constraints and the interpretation of reported dose.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Próstata
/
Bexiga Urinária
/
Radioterapia de Intensidade Modulada
Tipo de estudo:
Observational_studies
Limite:
Humans
/
Male
Idioma:
En
Revista:
Radiother Oncol
Ano de publicação:
2011
Tipo de documento:
Article