- 16 - * ee ¢ sd particle irradiation of deep respiratory tissue-?. The last two columns in Table III describe the radiation field around such a particle in the lung using Geesaman's lung mode17?, The dose rate to the entire organ is given in colum 2 of Table IIz for comparison. From Table III it is significant to note that with an assumed DF=1, the lung dose from the same particle varies by more than 8 orders of magnitude depending on whether one averages the dose over os the entire lung or calculates it on the basis of the tissue exposed, TABLE III Radiation Dose Rate Due to a Pu-239 Particle (1 u in diameter, 0.28 pci?) Soft -~Tissue 24 ’ Irradiated Mass of Tissue (0.4 ug _ Dose Rate (rem/yr) 21/ . 730,000 Lung Tissue Entire Ordan 1000 g Irradiated 27 0.0003 20 Alveoli 65 ug 19 ug 4000 11,000 Geesaman, Donald P., An Analyse from an Closest Inseciuscle plrohashrivvines fevers Lerotreeioin Respiratory Tissue, UCRL-303c7 anc UTRL-503 7 Lawrence Livermore Laboratory, Livermore, C Lift., 1965S.