These are great questions for your health care team... First - will you have a single or double mastectomy? Second - will you have reconstruction?
It depends on how things go for you... But, my guess is this.... If you are having a single mastectomy with no reconstruction, you are likely to be able to manage quite well on your own at home. If you are having a double mastectomy with no reconstruction, it's definitely still possible to manage on your own at home, but it will really depend on you. How much pain you have and how much mobility you have. I had a double mastectomy, and I had no problem managing my own drains and bandages, much to the annoyance of my better half who simply wanted to be helpful. But, being the stubborn human being that I am... I said - I can do it myself!
The drains themselves are easy as they are rather long tubes... and it doesn't require much twisting or turning to reach them and empty them out periodically.
If you are having reconstruction (I did not), then more pain is expected, according to others I've talked to about this. Hopefully, some folks who did reconstruction can weigh in here. With reconstruction, there are mobility restrictions about how high you should raise your arms and so on. So, you might need assistance at home due to those restrictions.
The injection at nuclear medicine is for determining which of your lymph nodes is the FIRST node for lymph drainage from your breast. That lets the surgical team minimize the number of nodes removed from your body. The goal is to keep the number of nodes removed as small as possible as lymph node removal can cause future problems, like lymphedema.
So, they inject a solution containing a marker that they can then image... and where you get a high concentration of the marker - that is your "sentinel node" - that is the first (and hopefully ONLY) node they will remove during surgery. Then, they will examine the lymph node right then and there to see whether they can detect the presence of cancer.
During the surgery, they may also use a blue dye to doubly confirm which node is the sentinel node. By the way, don't be surprised if your pee after surgery is blue...
So, there are some additional questions you should consider asking your health care team.
If the lymph node is positive for cancer, what will be the next step?
Options might include a full axilliary node dissection (removal of many lymph nodes) or radiation treatments after healing up from the mastectomy.
Another thing - the nurses should be able to teach you how to handle your drains and bandages. Ask loads of questions.
Did they tell you how long you should expect to be in the hospital? Seems like non recon folks stay 1-2 nights... and recon folks stay like 2-3 nights. I think that's mainly due to differences in pain management.
Well, I think that's about all I have... I hope this is helpful. Ask more questions!!! I'll do my best to answer according to my own experience and what folks have shared with me.