Twice-A-Day Irradiation

William M. Mendenhall, MD

By William M. Mendenhall, MD

Radiation therapy with external beam equipment is usually given once a day, 5 days a week, over a period of 6 to 8 weeks.  Altered fractionation schedules at the University of Florida consist of more than one treatment a day, most often two treatments per day, given over a slightly shorter time period in the range of 6 to 6½ weeks.

Another method is once-daily treatment, four days per week, and twice-daily treatment, one day per week, for six weeks. There is evidence that altered fractionation is associated with an improved chance of curing the cancer by decreasing the overall treatment time by a week to a week and a half. Altered fractionation may also reduce the risk of late complications by reducing the dose per treatment.

Twice-a-day irradiation has been employed at the University since 1978 for patients with cancers in a variety of tumor sites.  Data published from our institution, as well as elsewhere, indicate that in certain situations, twice-a-day radiotherapy is advantageous compared with once-daily conventional radiation treatment.

Before any treatment is started, the recommended treatment, the reasons it is recommended, the procedures to be carried out, the expected or possible side effects or complications, and the expected benefits are all explained to the patient and family. The patient must give permission for treatment, based on this knowledge (“informed consent”), before treatment is given.


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