Influence of different treatment techniques and clinical factors over the intrafraction variation on lung stereotactic body radiotherapy
Clin. transl. oncol. (Print)
; 18(10): 1011-1018, oct. 2016. tab, graf
Article
in English
| IBECS
| ID: ibc-155964
Responsible library:
ES1.1
Localization: BNCS
ABSTRACT
Purpose:
In the present study we compared three different Stereotactic body radiation therapy (SBRT) treatment delivery techniques in terms of treatment time (TT) and their relation with intrafraction variation (IFV). Besides that, we analyzed if different clinical factors could have an influence on IFV. Finally, we appreciated the soundness of our margins. Materials andmethods:
Forty-five patients undergoing SBRT for stage I lung cancer or lung metastases up to 5 cm were included in the study. All underwent 4DCT scan to create an internal target volume (ITV) and a 5 mm margin was added to establish the planning target volume (PTV). Cone-beam CTs (CBCTs) were acquired before and after each treatment to quantify the IFV. Three different treatment delivery techniques were employed fixed fields (FF), dynamically collimated arcs (AA) or a combination of both (FA). We studied if TT was different among these modalities of SBRT and whether TT and IFV were correlated. Clinical data related to patients and tumors were recorded as potential influential factors over the IFV.Results:
A total of 52 lesions and 147 fractions were analyzed. Mean IFV for x-, y- and z-axis were 1 ± 1.16 mm, 1.29 ± 1.38 mm and 1.17 ± 1.08 mm, respectively. Displacements were encompassed by the 5 mm margin in 96.1 % of fractions. TT was significantly longer in FF therapy (24.76 ± 5.4 min), when compared with AA (15.30 ± 3.68 min) or FA (17.79 ± 3.52 min) (p < 0.001). Unexpectedly, IFV did not change significantly between them (p = 0.471). Age (p = 0.003) and left vs. right location (p = 0.005) were related to 3D shift ≥2 mm. In the multivariate analysis only age showed a significant impact on the IFV (OR = 1.07, p = 0.007).Conclusions:
The choice of AA, FF or FA does not impact on IFV although FF treatment takes significantly longer treatment time. Our immobilization device offers enough accuracy and the 5 mm margin may be considered acceptable as it accounts for more than 95 % of tumor shifts. Age is the only clinical factor that influenced IFV significantly in ouranalysis:
RESUMEN
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Collection:
National databases
/
Spain
Database:
IBECS
Main subject:
Radiosurgery
/
Carcinoma, Non-Small-Cell Lung
/
Lung Neoplasms
Limits:
Humans
Language:
English
Journal:
Clin. transl. oncol. (Print)
Year:
2016
Document type:
Article
Institution/Affiliation country:
Clínica Universidad de Navarra/Spain
/
Complejo Hospitalario de Navarra/Spain