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 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 is the main goal of radiobiology?
Molecular Targets and Radiosensitivity A major goal of radiobiology is to achieve selective radiosensitization of cancer cells by modulating the molecular response to radiation injury.
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.
Which cells are the most radiosensitive?
Rapidly proliferating non-differentiated cells are the most radiosensitive. Well known representatives of this class of cells are the stem cells of the hematopoietic tissues and the cells of the intestinal crypts. The differentiated fixed postmitotic cells are the most radioresistant.
What is a common complication of stereotactic radiosurgery?
Tiredness and fatigue may occur for the first few weeks after stereotactic radiosurgery. Swelling. Swelling in the brain at or near the treatment site can cause signs and symptoms such as headache, nausea and vomiting.
What is bed in radiobiology?
BED = Biologically Effective Dose. • BED commonly used for isoeffective dose calculations. • BED is a measure of the true biological dose delivered. by a particular combination of dose per fraction and. total dose to a particular tissue characterized by a.
What is the study of radiobiology?
Radiobiology is a branch of science that deals with the action of ionizing radiation on biological tissues and their cellular and molecular components (Hall and Giacca, 2006).
What is redistribution in radiotherapy?
Redistribution: is defined by cells that survive a dose of radiation due to synchronisation in resistant phases of the division cycle and redistributing into more sensitive phases of the cell cycle during subsequent doses of radiation.
What tissue is the most sensitive to radiation therapy?
Lymphocytes (white blood cells) and cells which produce blood are constantly regenerating, and are, therefore, the most sensitive.
Which organ is the most sensitive to radiation?
Radiation in high doses can be dangerous no matter what, but some parts of the body are more sensitive than others. The most sensitive parts of the human body are the lymphoid organs, bone marrow, blood, testes, ovaries and intestines, according to the Collaboration for Nondestructive Testing[1].
What is alpha beta ratio in radiobiology?
The alpha/beta ratio is the dose where the linear as well as the quadratic component cause the same amount of cell killing. Generally speaking, the higher the alpha/beta ratio is, the more linear the cell survival curve is.
What is Bed and EQD2?
The important difference between BED and EQD2 is that BED reports an effective dose, while EQD2 gives the equivalent dose needed in 2 Gy/fx to achieve that effective dose.
What is the history of radiobiology?
The history of radiation biology started shortly after the discovery of X-rays in 1895 by Wilhelm Conrad Röntgen, who was awarded the first Nobel Prize in Physics in 1901. Within short time, X-rays were being used not only to take pictures of the internal organs of living people but also to treat a variety of diseases.
Who discovered radiobiology?
Hermann Joseph Muller
In 1927 Hermann Joseph Muller published research showing genetic effects, and in 1946 was awarded the Nobel prize for his findings. More generally, the 1930s saw attempts to develop a general model for radiobiology.
Why is radiotherapy therapy fractionated?
Radiotherapy is split into a number of treatments called fractions that are given over several weeks. Delivering a small fraction of the total radiation dose allows time for normal cells to repair themselves between treatments, thereby reducing side effects.
What organ is least sensitive to radiation?
Reproductive and gastrointestinal cells are not regenerating as quickly and are less sensitive. The nerve and muscle cells are the slowest to regenerate and are the least sensitive cells.
What is stereotactic radiosurgery, and what conditions does it treat?
Stereotactic radiosurgery is a very precise form of therapeutic radiation that can be used to treat abnormalities in the brain and spine, including cancer, epilepsy, trigeminal neuralgia and arteriovenous malformations. Stereotactic radiosurgery does not involve an incision or opening; it carefully
What are the side effects of stereotactic radiotherapy?
– Fatigue. Tiredness and fatigue may occur for the first few days after SBRT. – Swelling. Swelling at or near the treatment site can cause signs and symptoms such as a temporary increase in pain. – Nausea or vomiting.
What are the side effects of stereotactic radiosurgery?
There is a low risk of developing a second cancer in or near the radiation field.
What are the risks of stereotactic radiosurgery?
Risks. Stereotactic radiosurgery doesn’t involve surgical incisions, so it’s generally less risky than traditional surgery. In traditional surgery, you may have risks of complications with anesthesia, bleeding and infection. Early complications or side effects are usually temporary. They may include: Fatigue.