What are the 5Rs 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 principles of radiobiology?
The fundamental principles of radiobiology are repair, redistribution, reoxygenation, and repopulation. These are known as the “Four Rs” of radiobiology.
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.
What is reassortment radiotherapy?
Reassortment between fractions redistributes surviving cells over cell-cycle phases thus avoiding repeated irradiation in resistant phases. Repair influences the biological effects of dose rate and time between fractions. Reoxygenation is important for tumours containing acutely hypoxic fractions of malignant cells.
Which cells are the most radiosensitive?
The differentiated fixed postmitotic cells are the most radioresistant. This class includes the long-lived neurons, skeletal muscle cells and erythrocytes.
What is the purpose 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 is the importance of radiobiology?
Major applications of radiobiology In general, radiobiology has two major applications where it is essential that intellectual capital be maintained, (1) the understanding and management of radiobiological risks to human populations and (2) the use of radiotherapy in the treatment of cancer.
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.
Why do I have Hypofractionation?
It’s called hypofractionation. Using hypofractionation, or hypofractionated radiation therapy, more doses of radiation are delivered per treatment, so patients can complete their course of radiation therapy much faster than conventional treatment and costs patients less money.