skip to main content

Title: Repair of sublethal radiation injury after multiple small doses in mouse kidney: an estimate of flexure dose

Functional kidney damage in mice was measured after a series of fractionated X-irradiations. Doses per fraction of 0.75-12.5 Gy were given as 2, 5, 10, 30, 40, 60, or 80 equal doses in a total treatment time of 4 weeks. Renal function (measured by clearance of /sup 51/CrEDTA or hematocrit levels) deteriorated progressively, in a dose related manner, from 20 to 46 weeks after the start of treatment. The changes in renal function versus time were fitted by a polynomial regression through all data and interpolated values for /sup 51/CrEDTA clearance were then calculated at 30 and 40 weeks after treatment. Steep dose response curves were obtained and these were used to calculate isoeffective doses for the different fractionation schedules. There was a marked increase in total isoeffective doses from 2-30 fractions and these data were well described by a linear quadratic (L.Q.) expression for damage with an alpha/beta ratio of 2.3 +/- 0.2 Gy. There was only a slight increase in the total isoeffect dose as the size of the dose per fraction was decreased below 2 Gy and the measured isoeffect doses after 40 to 80 fractions were lower than predicted on the basis of an L.Q. modelmore » assuming complete repair between successive irradiations. The flexure dose for mouse kidneys irradiated 3 times per day was, effectively, 1 to 2 Gy and hyperfractionation using lower doses per fraction did not lead to significant, additional repair.« less
Authors:
; ; ; ; ; ;
Publication Date:
OSTI Identifier:
6273200
Resource Type:
Journal Article
Resource Relation:
Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States); Journal Volume: 5
Research Org:
Netherlands Cancer Institute, Antoni van Leeuwenhoekhuis, Amsterdam
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; KIDNEYS; BIOLOGICAL FUNCTIONS; BIOLOGICAL RADIATION EFFECTS; RADIATION INJURIES; BIOLOGICAL REPAIR; CHROMIUM 51; DOSE-RESPONSE RELATIONSHIPS; EDTA; FRACTIONATED IRRADIATION; ISODOSE CURVES; MICE; X RADIATION; AMINO ACIDS; ANIMALS; BETA DECAY RADIOISOTOPES; BIOLOGICAL EFFECTS; BIOLOGICAL RECOVERY; BODY; CARBOXYLIC ACIDS; CHELATING AGENTS; CHROMIUM ISOTOPES; ELECTROMAGNETIC RADIATION; ELECTRON CAPTURE RADIOISOTOPES; EVEN-ODD NUCLEI; FUNCTIONS; INJURIES; INTERMEDIATE MASS NUCLEI; IONIZING RADIATIONS; IRRADIATION; ISOTOPES; MAMMALS; NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANS; RADIATION EFFECTS; RADIATIONS; RADIOISOTOPES; RECOVERY; REPAIR; RODENTS; VERTEBRATES 560152* -- Radiation Effects on Animals-- Animals