Radiobiology

Radiobiology is the science that evaluates the radiation effects in living organisms. In the clinical oncology practice, radiobiology investigates the interactions between ionizing radiation and living systems and their interaction consequences. Atoms form molecules, molecules make macromolecules, macromolecules build complex organic structures, and finally cells which are the main tissue structure component reflecting all life features are formed. Cells are specialized according to their specific tissue functions and locations. Radiobiology in radiotherapy orientation dominantly focuses on electromagnetic spectrum with sufficient energy to induce ionization of atoms. Chemical bonds are ultimately broken leading to damage to important biomolecules. Basic concepts that are crucial to understanding radiotherapy-oriented radiobiology are reviewed in depth in this chapter.