Related Experiment Video
Updated: Jun 20, 2026
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Surface dose in the treatment of breast cancer with helical tomotherapy
Felix Zibold1, Florian Sterzing, Gabriele Sroka-Perez
1Department of Radiation Oncology, University of Heidelberg, Im Neuenheimer Feld 400, Heidelberg, Germany.
Purpose:
Investigation of the effects of breathing motion- and misregistration-induced errors on the superficial dose in the treatment of breast cancer using helical tomotherapy (HT).
Material And Methods:
Surface dose measurements were performed with thermoluminescence dosimetry (TLD). Two treatment plans with different planning target volume (PTV) definitions of the left breast were used: PTVskin had its ventral border exactly on skin level, while PTVair included also a 10-mm extension ventral to the PTVskin. With a thoracic static phantom, misregistration errors in an HT were simulated. A dynamic phantom was used to simulate a breathing patient during HT. Surface doses of breast cancer patients were measured both for an HT (179 points) and a conventional three-dimensional conformal treatment (70 points).
Results:
In the static phantom misregistration setup, dose deviations of -31.9% for PTVskin to +35.4% for PTVair could be observed. The dynamic phantom measurements resulted in surface dose deviations from those in a static position between 0.8% and 3.8% without a significant difference for the PTV definitions. The measured surface doses on patients averaged (mean +/- standard deviation) 1.65 +/- 0.13 Gy for the HT and 1.42 +/- 0.11 Gy for the three-dimensional conformal treatment.
Conclusion:
HT enables a homogeneous and reproducible surface dose with small dose deviations in the treatment of breast cancer. HT is a feasible method to treat breast cancer under free shallow breathing of the patient using a treatment plan with a ventral PTV border on the skin level.
