A study on the shoulder of cell survival curve in relation with repair capacity of cells after being irradiated

الملخص EN

Aim -to show that not all survival curves without shoulder are not able to repair or have lost the ability for the accumulation of $ublethal damage.

Background :- the shoulder of the survival cuive ١٠٩ considered as a region of accumulation of sublethal damage also as an indicator for ccll capacity to repair.

The size can be influcnccd by the change of the slope of the linear portion of the survival curve.

Results :- we have shown that in a survival curve with shoulder size of 1.5 Gy can be a straight line when the slope of the exponential part is changcd so the same region of the low dose of the same survival fraction can show shoulder at one tinic and with no shoulder at another.

connclusion:- we have shown that in sonic cases cell survival curve could lose its shoulder without the necessity of losing its capacity for repair.