This homework will focus predominantly on OER and dose fract

This homework will focus predominantly on OER and dose fractionation calculations A tumor which is 100% hypoxic is irradiated with a single X-ray dose of 18 Gy. The surviving fraction from this dose is measured to be 0.05. When a similar tumor in an air-breathing animal is given the same dose, the surviving action is found to be 0.01 in the second tumor. Calculate the fraction of hypoxic cells in second Two radiations were examined. For radiation type \"A\" D37 far cell survival (measured with oxygen present he system) was 2 Gy. Under the same circumstances, radiation type only 1 Sy tor the same result. the experiment was repeated using hypoxic conditions. For radiation type \"A\" the D37 was 6 Gy. and for type \"B\" t was 1.50y. What single actor is likely responsible for the different cell survival D 37 values of radiation A and B? This problem is intended for you to explore survival curves. Given a cell culture that has shown an alpha value of 0.17 and a beta value of 0.05 compare the alpha and beta contributions to cell killing, as well as the linear quadratic model for survival. Y answer should be in the form graph, and look something like this Comparison of Alpha and Beta Contributions to Cell Kling equal, The black dot represent real data, and indicate that at higher doses, the LQ model doesn\'t the data we Using the same alpha and beta values, create a plot that shows how dose fractionation enhances survival for this particular line. You should be able to create a graph that looks like this Effect of Dose

Solution

The surviving fraction S1 is 0.05% in those cells which are 100% hypoxic H1 for a single dose of 18Gy. The surviving fraction S2 of other cell is 0.01%, so the hypoxic level H2 for those cells would be

S1/S2 = H1/H2

0.05/0.01 = 100/H2

H2= 100/ 5 = 20%

20% cells were hypoxic in the second tumor.

For A type of radiation was 2 Gy and under same circumstances radiation for B type was 1Gy, which used for D37. Radiation is inversely proportional to survival of cells.

In case where D37 has given radiation A of 6Gy and type B has 1.5Gy, so A has radiation of

Now the D37 or 37% survival was for radiation A =2 Gy

So new survival rate = S1/ S2 = R2/R1 where R is radiation level and S is survival rate

37/S2 = 6/2

S2= 37/3 = 12.33%

For radiation B type

S1/S2 = 1.5/1

= 37/S2 = 1.5

S2 = 37/1.5 = 24.67%