- 27 ' “Sensitive to such intense localized radiation. C. C. ‘Lushbaugh reported on a lesion that developed as the result ‘of residual Pu-239 contained 0.08 ug from a puncture wouna’®, (0.005 uCi) The particle of Pu-239. “Commenting on the histological examination of the lesion, the authors state, "The autoradiographs showed precise confinement of alpha-tracks to the area of maximum damage and their penetration into the basal areas of the epidermis, where epithelial changes typical of ionizing radiation exposure were present. therefore, The .cause and effect relationship of these findings, seemed obvious. Although the lesion was minute, the changes in it were severe. Their similarity to known precancerous epidermal cytologic changes, of course, raised the question of the ultimate fate of such a lesion should it be allowed to exist without surgical intervention..." In this case, less than 0.1 ug of Pu-239 produced precancerous changes in human tissue. was Very intense. The dose to the surrounding tissue There is every reason to believe that a _._—o- smalier quantity of Pu-239 would have produced similar changes. This precancerous lesion indicates that a Single Pu-239 particle irradiates a significant (critical) volume of tissue and is capable of inducing cancer. 46/ Lushbaugh, C.C. and J. The Lushbaush study was Langham, Op. cit., po. 461-4164. s :