Published in:
01-11-2020 | Cervical Cancer | Original Article
Impact of changes in body contours on radiation therapy dose distribution after uterine cervical cancer surgery
Authors:
Motoharu Sasaki, Hitoshi Ikushima
Published in:
Japanese Journal of Radiology
|
Issue 11/2020
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Abstract
Purpose
Patients receiving postoperative irradiation for uterine cervical cancer might not be able to eat during radiation therapy because of the effects of concurrent chemo-radiotherapy; this may lead to changes in the patient’s body shape during treatment. When performing image-guided radiotherapy, it is necessary to determine immediately whether treatment can be performed on the day or whether re-planning is required. The purpose of this study was to determine indicators for re-planning by examining the effects of changing body contours on radiation therapy dose.
Materials and methods
The original body contour was reduced by 1 cm in the front portion (structure-set 1). Based on the original dose distribution, the dose recalculation was performed with a structure set created using the body contour of structure-set 1. The difference between the original and recalculated dose distributions of structure-set 1 was evaluated through gamma analysis (GA).
Result
In the GA results for dose distribution obtained via recalculation with structure-set 1, a pass rate of 90% or more was obtained for a criterion of 2 mm/2% in all cases.
Conclusions
The results suggest that dose re-planning is rarely required when the body shape is reduced by only 1 cm in the front.