What is alpha beta ratio in radiotherapy?
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 the common α β ratio for cancer cells?
However, the α/β ratio for fibroblasts (0.6-6 Gy) was far lower compared to that for the cancer cells (11-43 Gy), compatible with the overall clinical and experimental estimation of the α/β values in connective tissues (fibrosis), which is around 4 Gy (5,9-11).
What does a low alpha beta ratio mean?
Low alpha/beta ratios (1-3) indicate that the accumulation of multiple single hits produces increased lethality for higher doses. Cell survival plots for low alpha/beta ratio cells have a greater curvature. Data from Technical Basis of Radiation Therapy, 5th Edition Table 1. Tissue Type.
What is the alpha beta ratio for spinal cord?
Conclusion. The study suggests that the spinal cord has a similar α/β ratio for patients, rats and other large animals, such as dogs, monkeys, and pigs. The α/β ratio is close to 3.9 Gy, with a 95 % CI of (3.0, 4.9) for the combined group, and (2.2, 8.2) for the patient only group.
What is a major disadvantage of the therapeutic ratio?
01) What is a major disadvantage of the therapeutic ratio? Feedback: The therapeutic ratio is an indication of the relative dose levels of a drug which will be effective, versus those which will be lethal. It gives no indication of chronic or non-lethal toxicity.
What is relation between alpha beta and gamma?
The relation between alpha, beta, and gamma is given in the form of a ratio and the ratio is 1:2:3 and can be expressed as: α = β 2 = γ 3.
What is a relation between alpha and beta?
β=1−αα
What is a thecal sac?
Thecal sac is the outer covering of the spinal cord. This means there are bone spurs on the back of the spinal bones, putting pressure on or affecting the front part of the outer layer of the (neck) cervical spinal cord.
Does the presence of oxygen increase or decrease radiation damage?
The effect is used in medical physics to increase the effect of radiation therapy in oncology treatments. Additional oxygen abundance creates additional free radicals and increases the damage to the target tissue.
Is it better to have a high or low therapeutic index?
A higher therapeutic index is preferable to a lower one: a patient would have to take a much higher dose of such a drug to reach the toxic threshold than the dose taken to elicit the therapeutic effect.
Is a higher or lower therapeutic index better?
The larger the therapeutic index (TI), the safer the drug is. If the TI is small (the difference between the two concentrations is very small), the drug must be dosed carefully and the person receiving the drug should be monitored closely for any signs of drug toxicity.
What is the ratio of a ß and γ?
Derivation of the relation between alpha, beta, and gamma in thermal expansion is α:β:γ=1:2:3.
What is the most appropriate relation between alpha and beta?
β=1−α Complete step-by-step answer: Alpha of a transistor is defined as the current gain in the common base configuration which is in turn defined as the ratio of change in the collector current to change in the emitter current.