The time factor and repopulation in tumors and normal tissues

The tolerance of most normal tissues and the radioresistance of some and maybe most tumors increases as overall treatment time increases. In most cases this increase appears to be proportional to time. The time factor is measured by the additional dose that has to be delivered for a given additional time period to achieve the same effect, and is quantitated as Gy/d. Typical values for the time factor in human tumors, particularly squamous cell...