If you are considering radiation therapy, you must first meet with a radiation oncologist to see if radiation therapy is right for you. During your first visit, your doctor will evaluate your need for radiation therapy and its likely results. This includes reviewing 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. You may also be seen by a medical student, a resident (radiation oncologist in training), a nurse practitioner, a physician's assistant or a nurse.
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.
To be most effective, radiation therapy must be aimed precisely at the same target or targets each and every time treatment is given. The process of measuring your body and marking your skin to help your team direct the beams of radiation safely and exactly to their intended locations is called simulation.
During simulation, your radiation oncologist and radiation therapist place you on the simulation machine in the exact position you will be in during the actual treatment. Your radiation therapist, under your doctor's supervision, then marks the area to be treated directly on your skin or on immobilization devices. 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 either with a bright, temporary paint or a set of small, permanent tattoos.
Your radiation oncologist may request that special blocks or shields be made for you. These blocks or shields are put in the external beam therapy machine before each of your treatments and are used to shape the radiation to your tumor and keep the rays from hitting normal tissue. Multileaf collimators may also be used to shape the beam and achieve safe delivery of your radiation treatment.
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 to develop a treatment plan. Often, a special treatment planning CT scan is done to help with the simulation and treatment planning. This CT scan is in addition to your diagnostic CT scan. Frequently, sophisticated treatment-planning computer software is used to help design the best possible treatment plan. After reviewing all of this information, your doctor will write a prescription that outlines exactly how much radiation you will receive and to what parts of your body.