Mammosite is given twice a day for 5 to 7 days, depending on your set up. They would implant a receptacle that is later removed. The positive points of mammosite is you are done with it in a week and it does impart the radiation right to where it needs to be! However, you are also to stay away from people for an amount of time while you are doing the mammosite as you are somewhat "radioactive" and it does require a minimal surgery.
External beam radiation isn't as accurate but there is no surgery or implant and no radioactive time period. With this type, anything in it's path gets radiated even though they angle it to target the cancer/lymphnode area. And you go once a day, Mon - Fri for 7 to 8 weeks, depending.
If you ask me am I a fan of chemo and radiation, my answer is no. And I never will be. As a cancer survivor, I'm glad I did both to reduce my chance of recurrence. Thirty years later, there are a lot of strides in cancer treatment. Sadly, no cure. But the ladies that went before me and have passed on have given me and others like me a time tested clinical trial with their lives that prove that radiation helps to remission. They gave their lives so we could have one. God bless them all. Best wishes to you. Listen to your Doctors, take the other with a grain of salt.
Please check out your previous question, where I left a comment yesterday.