Radiation responses of cancer and normal cells to split dose fractions with uniform and grid fields: increasing the therapeutic ratio.

The findings show that the intra-fractional dose schedule with medium time delay offers an opportunity to increase the toxicity of radiation to cancer cells, relative to a single radiation delivery. For all cancer cell lines, a grid field gives a greater toxic effect than a uniform field. The split dose treatment offers an increase in cancer toxicity while preserving normal cells, improving the outcomes of a treatment.