so, the united states preventative services task force in 2009 came out with a proposal to revise guidelines saying that perhaps women aged 40 to 50, there's no cost benefit really for that age group in terms of having mammogram of average risk, so recommended that women start mammography at age ao where the benefits really out weigh the risk, you don't have 40 years left in your life span at that point perhaps, you have 30, you're at a less vulnerable stage of life so there are a lot more benefits for life, your breast cancer risks are higher, so you know, the age 40 to 50, there's still a lot of debate about that and women need to discuss this with their own health care providers, but recent research has found that women who are at high risk of breast cancer because of braque of mutation who then screening at earlier and earlier ages may be particularly vulnerable to radiation, so for them, alternatives to radiation based screening need to be, you know, used either in lieu of or in addition to and that's a very personal decision and a medical decision, but that added risk for those women w