A Study on the Shoulder of Cell Survival Curve in Relation With Repair Capacity of Cells After Being Irradiated

Aim - to show that not ail survival curves without shoulder are not able to repair or have lost the ability for the accumulation of sublethal damage. Background:- the shoulder of the survival curve is considered as a region of accumulation of sublethal damage also as an indicator for cell capacity to repair. The size can be influenced by the change of the slope of the linear portion of the survival curve. Results:- we have shown that a survival curve with shoulder size of 1.5 Gy can be a straight line when the slope of the exponential part is changed so the same region of the low dose of the same survival fraction can show shoulder at one time and with no shoulder at another. Conclusion:- we have shown that in some cases cell survival curve could lose its shoulder without the necessity of losing its capacity for repair.