If you are using the Rad Child perk, be aware that taking Chemist improves how well RadAway works. I like to stay at a minimum of 400 rads for healing. I got up to 600 rads in a Vault and did not want to drop some items because I lost strength. I took RadAway and dropped down below 200 rads (-429 rads!) and would not regenerate any more. I had the character go sit in a puddle of waste and went off to make a sandwich. I stockpiled over 80 doses of RadAway and now I don't want to use it unless I get over 839 rads. I guess I have to switch to Fiery Purgative to stay between 400 and 600, but it has weight so I have to worry about how much to carry around.