TITLE:
Effect of Breathing on Exposed Lung Volumes and Doses in Patients with Breast Carcinoma Receiving Radiotherapy
AUTHORS:
Evren Ozan Göksel, Evrim Tezcanli, Melahat Garipağaoğlu, Öznur Şenkesen, Halil Küçücük, Meriç Şengoz, Nuran Beşe, Işık Aslay
KEYWORDS:
Radiotherapy; Treatment Planning; Breast Carcinoma; Lung Volume; Lung Dose; Breath Cycle
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.2 No.3,
July
30,
2013
ABSTRACT: Introduction: This study evaluates the changes in the lung volume (LV) exposed radiation during the breath cycle and whether these volume differences have an effect on both lung and target doses in breast carcinoma patients. Material and Methods: Ten patients with left breast carcinoma underwent breast conservative surgery or mastectomy receiving radiotherapy (RT) (breast or chest wall and regional lymph nodes) were included. For this study, planning computerized tomography (CT) images were obtained during deep inspiration (DI) and end of expiration (EE), besides free breathing (FB) to simulate breath cycles. Three-dimensional conformal or intensity-modulated RT planning was done to obtain dose-volume information using CT series taken FB, DI and EE. The treatment plan was done with FB images and exported to the DI and EE scans and re-calculated. Volume changes and calculated dose differences according to breath cycles were compared. Results: There were significant differences in the whole LV, ipsilateral LV and contralateral LV between FB-DI and EE-DI while no significant difference was seen between FB and EE. V20 was lower during DI than FB and EE but the difference was not significant. There was no significant variation in whole breast dose although significant dose variations were observed in mean MI, supraclaviculary and level III axillary lymph node doses between breath cycles. Conclusion: Breath cycle had no significant effect on whole breast dose although significantly changed regional lymph node doses in patients with breast carcinoma receiving whole breast and regional lymph nodes radio-therapy. V20 dose was lower during DI than FB and EE, but the difference was not significant.