Skip to main content
PMC home page
The British Journal of Cancer. Supplement logoLink to The British Journal of Cancer. Supplement
. 1984;6:263–269.

Tissue repair capacity and repair kinetics deduced from multifractionated or continuous irradiation regimens with incomplete repair.

H D Thames Jr, H R Withers, L J Peters
PMCID: PMC2149147  PMID: 6582915

Abstract

A model is proposed to account for cell survival after multiple doses, when the interfraction interval is insufficient for complete Elkind repair. In the limit of ever-increasing numbers of ever-smaller fractional doses, the model transforms into the accumulation model (Roesch, 1978) of survival after continuous irradiation. When it is adapted to describe tissue responses to isoeffective multifractionated regimens, wherein repair is incomplete, a generalization of the usually linear plot of reciprocal total dose versus dose per fraction is obtained, in which downward curvature is evident. There is some advantage in studying tissue responses to multifractionated regimens with incomplete repair in the interfraction intervals, or continuous exposures at various dose rates since in addition to determination of repair capacity (defined by beta/alpha) there is an estimate of repair kinetics (defined by the halftime T1/2 for repair of sublethal injury). There is a saving in overall treatment time with either method, thereby reducing the influence of regeneration on the interpretation of the results. The results of analyses of previously published data are presented to illustrate the use of the models. Estimated from the response of three acutely responding normal tissues in the mouse (jejunum, colon and bone marrow), repair halftimes ranged from 0.3-0.9 h and values of beta/alpha were approximately 0.1 Gy-1. From the response of mouse lung (LD50 for pneumonitis) to multifractionated regimens with incomplete repair, the repair halftime was estimated at 1.5 h and beta/alpha was 0.27 Gy-1. In the rat spinal cord beta/alpha was 0.7 Gy-1 and T 1/2 was 1.5 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Full text

PDF

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Douglas B. G., Fowler J. F. The effect of multiple small doses of x rays on skin reactions in the mouse and a basic interpretation. Radiat Res. 1976 May;66(2):401–426. [PubMed] [Google Scholar]
  2. Field S. B., Hornsey S., Kutsutani Y. Effects of fractionated irradiation on mouse lung and a phenomenon of slow repair. Br J Radiol. 1976 Aug;49(584):700–707. doi: 10.1259/0007-1285-49-584-700. [DOI] [PubMed] [Google Scholar]
  3. OLIVER R. A COMPARISON OF THE EFFECTS OF ACUTE AND PROTRACTED GAMMA-RADIATION ON THE GROWTH OF SEEDLINGS OF VICIA FABA. II. THEORETICAL CALCULATIONS. Int J Radiat Biol Relat Stud Phys Chem Med. 1964;8:475–488. doi: 10.1080/09553006414550581. [DOI] [PubMed] [Google Scholar]
  4. Simnett J. D., Heppleston A. G. Cell renewal in the mouse lung. The influence of sex, strain, and age. Lab Invest. 1966 Nov;15(11):1793–1801. [PubMed] [Google Scholar]
  5. Thames H. D., Jr, Peters L. J., Withers H. R., Fletcher G. H. Accelerated fractionation vs hyperfractionation: rationales for several treatments per day. Int J Radiat Oncol Biol Phys. 1983 Feb;9(2):127–138. doi: 10.1016/0360-3016(83)90089-5. [DOI] [PubMed] [Google Scholar]
  6. Thames H. D., Jr, Withers H. R., Peters L. J., Fletcher G. H. Changes in early and late radiation responses with altered dose fractionation: implications for dose-survival relationships. Int J Radiat Oncol Biol Phys. 1982 Feb;8(2):219–226. doi: 10.1016/0360-3016(82)90517-x. [DOI] [PubMed] [Google Scholar]
  7. Thames H. D., Jr, Withers H. R. Test of equal effect per fraction and estimation of initial clonogen number in microcolony assays of survival after fractionated irradiation. Br J Radiol. 1980 Nov;53(635):1071–1077. doi: 10.1259/0007-1285-53-635-1071. [DOI] [PubMed] [Google Scholar]
  8. Thames H. D., Jr, Withers R., Mason K. A., Reid B. O. Dose-survival characteristics of mouse jejunal crypt cells. Int J Radiat Oncol Biol Phys. 1981 Nov;7(11):1591–1597. doi: 10.1016/0360-3016(81)90091-2. [DOI] [PubMed] [Google Scholar]
  9. Travis E. L., Down J. D. Repair in mouse lung after split doses of X rays. Radiat Res. 1981 Jul;87(1):166–174. [PubMed] [Google Scholar]
  10. Tucker S. L., Withers H. R., Mason K. A., Thames H. D., Jr A dose-surviving fraction curve for mouse colonic mucosa. Eur J Cancer Clin Oncol. 1983 Mar;19(3):433–437. doi: 10.1016/0277-5379(83)90143-8. [DOI] [PubMed] [Google Scholar]
  11. Withers H. R., Mason K. A. The kinetics of recovery in irradiated colonic mucosa of the mouse. Cancer. 1974 Sep;34(3):suppl–suppl:903. doi: 10.1002/1097-0142(197409)34:3+<896::aid-cncr2820340717>3.0.co;2-p. [DOI] [PubMed] [Google Scholar]

Articles from The British Journal of Cancer. Supplement are provided here courtesy of Cancer Research UK

RESOURCES