Local dose-effect relations for lung perfusion post stereotactic body radiotherapy.
Radiother Oncol
; 107(3): 398-402, 2013 Jun.
Article
em En
| MEDLINE
| ID: mdl-23623727
ABSTRACT
PURPOSE:
To model the local dose-effect relation for lung perfusion reduction in lung cancer patients treated with stereotactic body radiotherapy (SBRT). MATERIALS ANDMETHODS:
Forty-two patients having upper-lobe peripheral tumours <5 cm treated with SBRT (3×18 Gy) underwent single-photon emission computed-tomography (SPECT) scans to measure the lung perfusion 2 weeks pre-SBRT, 4-months post-SBRT, and for 8 patients 15-months post-SBRT. The relation between the calculated relative local perfusion reduction and the normalised total dose (α/ß=3 Gy) at 4-months post-SBRT was modeled by 3-parameter logistic model and 2-parameter linear-maximum model.RESULTS:
The relation between local dose and perfusion reduction at 4-months post-SBRT showed a maximum effect of 42.6% at doses >100 Gy and was best described by the logistic model with parameters (95% CI) M=42.6% (40.7-44.6), D50=28.7 Gy (26.3-31.1) and k=2.2 (1.8-2.5). A significant increase of this maximum effect to 65.2% was found at 15-months post-SBRT.CONCLUSIONS:
The relation between local dose and perfusion reduction in patients treated with SBRT can be modeled by a 3-parameter logistic model. This demonstrated relationship 4-months post-SBRT approaches a plateau for doses >100 Gy, where 90% of the maximum lung-perfusion reduction is observed at NTD=78 Gy. A further perfusion reduction compared to 4-months post-SBRT was observed fifteen months post-SBRT.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Radiocirurgia
/
Pulmão
/
Neoplasias Pulmonares
Tipo de estudo:
Risk_factors_studies
Limite:
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Radiother Oncol
Ano de publicação:
2013
Tipo de documento:
Article