PURPOSE: TO DETERMINE WHETHER A SEX DIFFERENCE EXISTS FOR RADIATIONINDUCED LUNG CANCERS ACROSS ALL AVAILABLE EXPOSED POPULATIONS. TO ADDRESS THE ISSUES OF TRANSFERRING RISKS FROM ONE EXPOSED POPULATION (E.G. THE JAPANESE ATOMIC BOMB SURVIVORS) TO ANOTHER (I.E. THE ASTRONAUT POPULATION). TO EVALUATE THE OPTIMUM WAYS FOR INCORPORATING THE SEXSPECIFIC LUNG CANCER RISKS INTO THE NASA LIFETIME RISK PROJECTION MODEL. TO PUBLISH AN NCRP COMMENTARY WITH RECOMMENDATION ON THE SEX-SPECIFIC LUNG CANCER RISK COEFFICIENTS TRANSFER MODELS AND LIFETIME CANCER RISK PROJECTIONS.