General Core of Radiography – Limited Scope Practice Test 2026 - Free Radiography Practice Questions and Study Guide

Radiosensitivity increases in cells that are actively dividing, are less differentiated, and have a long future capacity to divide. According to Bergonie and Tribondeau, these factors mean the cell is more vulnerable to radiation because its DNA is actively being replicated and its proliferative potential is high, so radiation-induced damage more readily disrupts its growth and survival.

Young and undifferentiated cells fit this profile: they are still in development, divide frequently, and haven’t specialized fully, giving them the greatest chance of radiation-induced lethality or dysfunction. In contrast, mature and differentiated cells have lower mitotic activity, old or nondividing cells are in a quiescent state, and cells with limited division potential are less radiosensitive.

So, the cells described as young and undifferentiated are the most radiosensitive.