1. Oncology Center, Medical Physics Department, Bydgoszcz , Poland
2. Chair and Clinic Oncology and Radiotherapy, Nicolaus Copernicus University, Toruń , Poland
3. Institute of Physics, Nicolaus Copernicus University, Toruń , Poland
4. Faculty of Technical Physics, Poznan University of Technology, Poznan , Poland
5. Institute of Physics, Kazimierz Wielki University, Bydgoszcz , Poland