Relative effectiveness of 12-hourly fractionation and a non-uniform X-ray schedule in the optimum fractionation of C3H mouse mammary tumours
- 1 July 1975
- journal article
- Published by Oxford University Press (OUP) in The British Journal of Radiology
- Vol. 48 (571), 581-589
- https://doi.org/10.1259/0007-1285-48-571-581
Abstract
In previous experiments the highest proportions of tumours controlled for 150 days at a particular level of skin reaction were obtained with five or nine fractions of X rays in nine or ten days respectively. Poor results were obtained for the same numbers of fractions given in 4 or 18 days respectively. The present work reports results of three "non-standard" fractionation schedules: two with equal doses given at 12-hour intervals over four or nine days and one with eight decreasing doses given at decreasing intervals over 11 days. The two 12-hour interval schedules gave results which were equal to the best obtained by any other schedule tested. The 8F/11d non-uniform schedule, however, gave mediocre results in spite of being close to the previously optimum overall time. When these results are compared with previously published results from the same tumour system two, phases of optimum fractionation are demonstrated. At short overall times, up to four days, the situation is finely balanced, so that fraction size and interval matter greatly and results of the schedules vary from good to bad. At longer overall times, of nine days or more in these tumours, the response is no longer so variable. Eighteen days (two to three times the average volume doubling time) is too long for any successful treatment with this system, presumably because of proliferation in the tumour.Keywords
This publication has 7 references indexed in Scilit:
- Radiosensitization of C3H Mouse Mammary Tumours by a 2-Nitroimidazole DrugBritish Journal of Cancer, 1974
- Optimum fractionation in X-ray treatment of C3H mouse mammary tumoursThe British Journal of Radiology, 1974
- Skin Reactions in Mice after Multifraction X-irradiationInternational Journal of Radiation Biology and Related Studies in Physics, Chemistry and Medicine, 1974
- A simplification in the use of the NSD concept in practical radiotherapyThe British Journal of Radiology, 1973
- Changes in the rate of repopulation during multifraction irradiation of mouse skinThe British Journal of Radiology, 1973
- Fractionation with X rays and neutrons in mice: response of skin and C3H mammary tumoursThe British Journal of Radiology, 1972
- Dose, time and fractionation: A clinical hypothesisClinical Radiology, 1969