dna analysis cervical and vaginal cancer cells during radiotherapy by rapid highresolution cytometry the dna content of the nuclei of cancer cells of 12 cases of cervical cancer and 2 cases of vaginal cancer treated with radiotherapy were studied in 50 specimens specimens were taken from each case before radiotherapy and at the totals of 1000 rad 2000 rad 3000 rad and 4500 rad or 5000 rad all specimens were stained by the papanicolaou method and were analyzed by rapid highresolution cytometry total optical density mean nuclear area and the 5nexceeding rate 5ner increased gradually following irradiation cancer cells disappeared in good response cases before 3000 rad eight smears with a 5ner under 100 at the dose of 3000 rad or more seemed to be poor response cases low 5ner and low mean nuclear areas were observed in both patients who died with persistent disease after radiotherapy as well as in one case treated with chemotherapy for persistent disease after radiotherapy