What are the 5 Rs of radiobiology?

What are the 5 Rs of radiobiology?

In conventional radiotherapy (RT), the relative biologic effectiveness of radiation is influenced by radiobiological determinants, the so-called ‘5Rs’: Repair, Repopulation, Redistribution, Reoxygenation, and Radiosensitivity.

What is the role of radiobiology?

Radiobiology studies the interactions of ionizing radiation on atomic and molecular structures and consequently their induced effects on cells, tissues, and organs, both normal and diseased. As such, radiobiology enhances the understanding of biological outcome (harm or benefit) from ionizing radiation exposure.

What are the principles of radiotherapy?

Radiotherapy ionises chemicals within cells. The crucial lesion is DNA strand breakage which may be repaired or fixed and lead to apoptotic or mitotic cell death. Different types of normal and malignant cells vary in their susceptibility to ionising radiation.

Which cells are the most radiosensitive?

Amongst the body cells, the most sensitive are spermatogonia and erythroblasts, epidermal stem cells, gastrointestinal stem cells. The least sensitive are nerve cells and muscle fibers. Very sensitive cells are also oocytes and lymphocytes, although they are resting cells and do not meet the criteria described above.

What are the principles of radiobiology?

The fundamental principles of radiobiology are repair, redistribution, reoxygenation, and repopulation. These are known as the “Four Rs” of radiobiology. The concept of split dose repair was operationally described by Elkind in the 1960s.

What are the 4 R of radiobiology?

In general, success or failure of standard clinical radiation treatment is determined by the 4 R’s of radiobiology: repair of DNA damage, redistribution of cells in the cell cycle, repopulation, and reoxygenation of hypoxic tumor areas.

What are the three principles of radiation safety?

ALARA means avoiding exposure to radiation that does not have a direct benefit to you, even if the dose is small. To do this, you can use three basic protective measures in radiation safety: time, distance, and shielding.

What factors affect radiosensitivity?

Radiosensitivity depends on several factors. These factors include the ability to repair damage, hypoxia, cell cycle position, and growth fraction. In addition, the volume of the initial tumor has been demonstrated to influence the ability to eradicate tumors.

What is cell radiosensitivity?

Radiosensitivity is the relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation. In general, it has been found that cell radiosensitivity is directly proportional to the rate of cell division and inversely proportional to the degree of cell differentiation.

What is the study of radiation called?

Radiobiology (also known as radiation biology, and uncommonly as actinobiology) is a field of clinical and basic medical sciences that involves the study of the action of ionizing radiation on living things, especially health effects of radiation.