If a dose is delivered over a long period rather than all at once, the biological effect is:

If a dose is delivered over a long period rather than all at once, the biological effect is:

• A. Less Than If Delivered All at Once
• B. The Effect Will Be Greater Than a Single Dose
• C. The Effect Will Be the Same
• D. Unpredictable

Answer: (A)

The amount of biological effect from radiation depends not only on the total dose but also on how quickly it is delivered. If the dose is spread out over a longer period, cells have time to repair sublethal DNA damage between exposures. That repair reduces the overall damage, so the same total dose causes less biological effect than if it were delivered all at once. Delivering the dose in a single, rapid burst accumulates damage with little time for repair, leading to a greater effect.

The amount of biological effect from radiation depends not only on the total dose but also on how quickly it is delivered. If the dose is spread out over a longer period, cells have time to repair sublethal DNA damage between exposures. That repair reduces the overall damage, so the same total dose causes less biological effect than if it were delivered all at once. Delivering the dose in a single, rapid burst accumulates damage with little time for repair, leading to a greater effect.