# Survival Curves Radiation Biology

*Does low or high LET radiation show the shoulder. At the Y axis, what does a non threshold curve mean. It is also convention to express BED in units of Gy/ to indicate the effects to which the result apply. The shoulder, what does the shoulder represent, an area where the radiation is killing cells but is still accumulating damage. *

## Cell survival curve - SlideShare Module 6 Survival curves - inpp, Ohio University

What is the normal n number for humans. What is the n number on the cell survival curve representing. And Determination 100 D Survival 10-1 D Dose, Gy24.

LET Low-LET radiations: low dose region survival shoulder region appears high dose region survival curve becomes linear bars and surviving fraction to an exponential function of dose surviving fraction is a dual exponential S survival e-( D D2)34. Dose rate effect. M Terms of Service - what you can, what you should not etc.

### Cell Survival Curve - Virginia

The shoulder, what does the shoulder represent, an area where the radiation is killing cells but is still accumulating damage.

Linear Quadratic Model 2 S e-( D D ) where: S represents the fraction of cells surviving D represents dose and are constants that characterize the slopes of the two l portions of the semi-log survival curve biological endpoint is cell death.

D1,reduces survivivig fraction.37.

Composite survival curves for 40 Human Cell Lines Less variation Low Dose Rate: Survival Curves show greater variation, Greater range in repair skills times. OER is lower for types of radiation predisposed to killing cells by single-hit mechanisms. Fractionation If the dose is delivered as equal fractions with sufficient Dq time,repair of sub-lethal n expDq / D0 damage ocurs 104 103 Elkind s cars Recovery takes place 102 between radiation exposure, Dq 101 cell act as fresh target. Cell Death Estimation of Survival / Plating Efficiency Nature of Cell killing etc.

High-LET radiations: survival curve is linear surviving fraction is a pure exponential function of dose S e-( D). Radioresistant, a non threshold curve would begin where on a graph. Terminal portion follow exponential relationship means same dose increment result into equal reduction in surviving fraction. Age response:Cell Cycle Late Sleast sens. It means there is a dose of radiation below which there is no biological response. From stock culture and placed in seed dishes Then irradiated (0 Gy to 6 Gy)and allowed to grow into colonies for 1-2 weeks Colonies have been counted for survival data.

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### Basic radiobiology - irsn

Something does not work as expected? Vandana, King Georges Medical University, Lucknow. The survival curve for a multifraction regimen is also an exponential function of dose. The Oxygen Effect Oxygen modifies the biological effects of ionizing radiation 02 effect does not require that 02 be present during radiation just added within 5 msec after generation of free radical OER oxygen enhancement ratio: ratio of hypoxic: aerated doses needed to achieve the. Create a clipboard You just clipped your first slide!

Survival data are fitted by many models. View and manage file attachments for this page. Derivation of Survival Curves Always will have a control Cells have been taken batch to determine.