What to Expect Before Treatment

What Happens Before Cancer Treatment

Meeting With a Radiation Oncologist

During your initial consultation, your doctor will evaluate your need for radiation therapy. Your physician will review your current medical problems, past medical history, past surgical history, family history, medications, allergies and lifestyle. The doctor will also perform a physical exam to assess the extent of your disease and judge your general physical condition.

After reviewing your medical tests, including CT scans, MRI scans and PET scans, and completing a thorough examination, your radiation oncologist will discuss with you the potential benefits and risks of radiation therapy and answer your questions. For a list of questions that you may want to ask, please see the section “What Questions Should I Ask My Doctor?” (Links to Questions To Ask Your Doctor Page)


To be most effective, radiation therapy must be aimed precisely at the target or targets each and every time treatment is given. The process of planning your treatment requires obtaining a specialized CT scan.

During simulation, your radiation oncologist and radiation therapist place you on the CT scan machine in the exact position you will be in during the actual treatment. Your radiation therapist, under your doctor’s supervision, then places marks on your skin or on an immobilization device. Immobilization devices are molds, casts, headrests or other devices that help you remain in the same position during the entire treatment. The radiation therapist marks your skin and/or the immobilization devices with a temporary marker or a set of small, permanent tattoos.

Treatment Planning

Once you have finished with the simulation, your radiation oncologist and other members of the treatment team review the information they obtained during simulation along with your previous medical tests, such as MRIs, PET/CTs or CT scans, to develop a treatment plan.  Sophisticated treatment-planning computer software is used to help design the best possible treatment plan.