1. 1Faculty of Technical Physics, Poznan University of Technology, Piotrowo 3, 60-965 Poznań, Poland
2. 2Institute of Physics, Kazimierz Wielki University, Powstańćow Wielkopolskich 2, 85-090 Bydgoszcz, Poland
3. 3Medical Physics Department, Oncology Center, I. Romanowskiej 2, 85-796 Bydgoszcz, Poland