International Journal of Hematology and Oncology 2018, Vol 28, Num 4 Page(s): 201-207
Relationship Between Target Delineation and Surface Dose in Breast Radiotherapy Using Helical Tomotherapy

Suheyla Aytac ARSLAN1, Gonca Altinisik INAN2, Ipek Pınar ARAL2, Selcan CELIK2, Havva KARABUGA2, H. Furkan OZTURK2

1Yildirim Beyazit University, Faculty of Medicine, Department of Radiation Oncology, Ankara, TURKEY
2Atatürk Eğitim Araştırma Hastanesi, Department of Radiation Oncology, Ankara, TURKEY

Keywords: Delineation, Surface dose, Breast cancer, Helical Tomotherapy, Breathing
To investigate the effect of different planning target volumes (PTVs) and the breathing motion on the surface dose with Helical Tomotherapy (HT). Irradiations with different target volumes (PTV-3, PTV0, PTV+5) using a male randophantom placed on a dynamic platform were performed and measured with MOSFET. The irradiation of the phantom on the dynamic platform revealed that at least 75%, 91% and 104% of the predicted surface dose obtained for PTV-3, PTV 0 and PTV+5, respectively. Statistically significant difference was observed between static and dynamic measurements for PTV-3 (p= 0.02). Surface dose was decreased with increased breathing frequency and amplitude for PTV 0 without statistical significance. HT enables an effective surface dose in chest wall radiotherapy irrespective of the respiratory movement. The delineation is an important aspect of superficial moving targets such as chest wall in treatment with HT. The effect of breathing motion on surface dose is observed most obviously on cropped PTVs.