Repair in mouse lung between multiple small doses of X rays

Journal Article · Sun May 01 00:00:00 EDT 1983 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575967· OSTI ID:5504609

Travis, E L ^[1]; Parkins, C S; Down, J D; Fowler, J F; Thames, H D

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1. National Inst. of Health, Bethesda

Multiple fraction experiments have been carried out to determine the response of mouse lung to repeated small doses of 240 kV X rays down to 150 rad/fraction using breathing rate and lethality to assess damage. Two experimental approaches were used to measure the effect of small doses in vivo: (1) multiple equal doses and (2) multiple priming doses followed by a large test dose. Analysis was performed using the multitarget two-component model and the linear test dose. The amount of repair was calculated as a function of either dose per fraction (F/sub R/) or total dose (F/sub rec/). Both F/sub R/ and F/sub rec/ increased with decreasing dose per fraction but the change in F/sub R/ was small. The advantage of F/sub rec/ was that it varied more rapidly with dose per fraction than F/sub R/, so that possible differences between tissue repair capabilities are more visible on plots of repair as a function of dose per fraction. F/sub R/ and F/sub rec/ both decreased with the level of single-dose isoeffect injury; thus neither parameter is acceptable for comparing repair capability of different normal tissues with widely differing single-dose end point levels. Beta/alpha values were calculated and found to be a more acceptable index of repair capability than either F/sub R/ or F/sub rec/ because unlike those two parameters, ..beta../..cap alpha.. varied little with level of damage. Beta/alpha values of 1.7 to 4.2 krad/sup -1/ were obtained for both lung death and increased breathing rate and are clearly intermediate between the lower ..beta../..cap alpha.. ratios for acute reactions, i.e., skin and intestine, and the higher values for late reactions in kidney and spinal cord.

• OSTI ID: 5504609
• Journal Information: Radiat. Res.; (United States), Vol. 94:2
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
LUNGS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL REPAIR
DOSE-RESPONSE RELATIONSHIPS
EXPERIMENTAL DATA
FRACTIONATED IRRADIATION
LETHAL DOSES
MICE
X RADIATION
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RECOVERY
BODY
DATA
DOSES
ELECTROMAGNETIC RADIATION
INFORMATION
IONIZING RADIATIONS
IRRADIATION
MAMMALS
NUMERICAL DATA
ORGANS
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
560152* - Radiation Effects on Animals- Animals