Radiobiological effects of high-let particles: DNA strand breaks

Fundamental studies in radiation biology with high-LET charged particles involve a systematic study of the physical, chemical, molecular and cellular processes. Water molecules and DNA present inside a cell constitute the important targets for energy deposition which eventually lead to either cell death or mutation or transformation. High-LET charged particles are very efficient in causing these of damages. One of the primary lesions for causing injury to a cell is the production of DNA strand breaks. A good understanding of these breaks is essential before ultimate biological effects of heavy particles can be predicted. Based on known molecular mechanisms of the formation of strand breaks, a theoretical model is presented along with a comparison between the predictions of the model and experimental data. The studies have shown that LET is not a convenient physical parameter to relate the extent of strand breaks and one needs to know the microscopic distribution of energy (track structure). A discussion has also been presented to provide a background on various radiobiological characteristics of high-LET charged particles from the point of view of their uniqueness in damaging cancer cells