A reduction in overall treatment time without change in total dose is known as:

The correct answer refers to a treatment approach where the total dose of radiation remains the same, but the overall treatment time is reduced by increasing the frequency of treatments. This method is known as accelerated fractionation.

In accelerated fractionation, patients receive additional doses of radiation in a given timeframe, which can lead to a more effective treatment outcome by minimizing the time cancer cells have to recover between doses. This strategy is particularly beneficial for certain types of tumors where rapid treatment can improve local control and potentially enhance patient prognosis.

The other treatment options mentioned serve different purposes. Hypofractionation involves delivering a higher dose per session over fewer sessions but is not specifically about reducing the overall treatment time while maintaining the same total dose. Protraction refers to the method of spreading the total dose over a longer period, which is the opposite of what is being asked. Elapsed day reduction is not a standard term used in radiation therapy to describe a treatment strategy, particularly one focused on maintaining total dose while decreasing duration.