The bone scan being that your sister has cancer I do believe is to check the bones to see if the cancer has spread there. I think a cat-scan does not show if the cancer is in the bone. It will show the bones in the scan but not the cancer. Hope this gives you a better idea. Always ask as many question as you need to get your answers. Hope you have a good day.

Father with Kidney cancer and bone scan shows its gotten in more of his bones. I dont believe this is good. As kidney cancer has few treatment options.
:angel: