Pediatric oncologist + a family?

i REALLY want to be a pediatric oncologist but I dont want to be one if I am on call 24/7 and cant do anything but be stuck in a hospital. I wont be working in my own private office but with a hospital like St. Jude or something similar. Would I still be on call 24 hours a day or will someone else be there during the night or something? I really want t o help kids fight cancer but I also want a husband and kids and a life of my own along with it. but is it possible? thnx!