What imaging tests are used to check for skin cancer spread?

When we need to check if a skin cancer is spread, there are a number of different imaging tests which we can use depending on what we're looking for. A CT scan can be used to check for internal organs or bony change. An MRI is useful to look at brain and soft tissues and sometimes a PET CT scan is used when a small amount of a radioactive tracer is injected to look for active cancer cells within the body. We sometimes use a test called a sentinel lymph node biopsy to test the first lymph node which a cancer would travel to and by biopsying this lymph node this can help stage the cancer and we also sometimes use ultrasound particularly when we want to look at lymph nodes.