The time-dose relationship for radiation-induced lung damage in pigs.
The dose-time relationship of radiogenic pneumopathy was studied in 68 young pigs. The right lungs of the animals were irradiated by means of a telecobalt unit. Dose distribution calculations and the preparation and execution of irradiation were chosen to largely parallel the treatment of patients. The radiation response of the lungs was quantified by chest-X-rays, functional studies and histological and biochemical investigations of the autopsy specimens. The dose which produced unambiguous signs of radiation pneumopathy in at least 50% of the individuals (ED50), was used to draw an iso-effect plot. A steep slope of the iso-effect line was found when the number of fractions was increased from 5 to 15. In contrast, the iso-effect line showed only a small slope when the influence of overall time was investigated. Significant differences between doses for early and late reactions of the lungs could not be detected. The radiogenic lung reaction in pigs is adequately described by the relation D approximately N0.32 X T0.05 and an alpha/beta value of 3.7 Gy. These results are in a good agreement with those derived for mice by other investigators. The good comparability of the biological findings obtained with pigs to man points to the application of this dose-time relation in radiotherapeutical practice.
Herrmann
T
T
Voigtmann
L
L
Knorr
A
A
Lorenz
J
J
Johanssen
U
U
D000818:Animals; D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D008171:Lung Diseases / Q000209:etiology* / Q000473:pathology; D008433:Mathematics; D011833:Radiation Injuries, Experimental / Q000209:etiology* / Q000473:pathology; D011879:Radiotherapy Dosage; D013552:Swine; D013997:Time Factors
D003037:Cobalt Radioisotopes