Don't want much do you? Working out the fallout patterns from an attack took a large number of people running multiple scenarios back in the day, and then you have to apply decay curves for 50-odd isotopes and then make a bunch of assumptions about sources of food and water and then work out the effects on various organs. Remember that background radiation levels mean very little - what counts is the biological dose, and that is dependent both on the isotope and how it is absorbed. Even then, the biological dose doesn't translate very clearly into health effects - the linear no-threshold model is based on very little data indeed, with the low level dose effects being based on pure guesswork.