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Illuminating the "Black Box"

Wednesday, May 04, 2016

By Jamie Blom, M.D.

To most patients (and many physicians, frankly), the whole concept of radiation oncology might as well be a big black box.  Most patients understand surgery pretty well.  Many patients at least have a general impression of chemotherapy (“I’m going to lose my hair and vomit”).  These impressions may or may not be accurate, but for many patients having some concept of what possibly could happen at least gives them some sense of comfort.  Anxiety over the unknown is a powerful emotion.  Very few people, however, have any accurate pre-conception of what is in store for them if they have to undergo radiation therapy… but they’ve heard all kinds of stories!  Allow me to shed some light into this black box.

First of all, it’s important to realize that “radiation therapy” is an extraordinarily diverse experience.  A gentleman with prostate cancer, versus a woman with breast cancer, versus a person with throat cancer will all manifest dramatically different experiences.  Moreover, even among patients with what appear to be the “same” cancers, there can be very significant differences and reactions.  For this reason, we encourage all patients to be very proactive in asking questions of their radiation oncologist.  You need to keep in mind that we are here for YOU.  Your radiation oncologist is the one person who knows the most about your particular situation from the radiation perspective.  He or she is therefore in the best position to answer your question as best we can.  Our job is to be your resource; please use us!  Our patients don’t have to like the decisions or treatments they decide to take, but we strive to do all we can to make them comfortable with the decisions they make.

The treatments themselves can vary tremendously.  Some are single dose; some can be up to eight or nine weeks long.  The machines and techniques with which you may be treated can vary tremendously as well.  You should feel comforted that our physicians have at our disposal the most sophisticated technology in all of radiation oncology.  Some of the names you may hear are “IMRT”, “TomoTherapy”, “CyberKnife”, and “High Dose Rate brachytherapy.” Since we are blessed with this breadth of state-of-the-art equipment, your radiation oncologist will match the most appropriate technology and technique to your individual situation, and we will be happy to explain why we make the decisions we do.

Treatments do have some commonalities, however.  Treating any patient’s cancer is predicated upon the ability to 1) identify the tumor or area of interest within the body, and 2) ensure that we can deliver radiation in an extraordinarily precise fashion to this target.  The process starts with what is referred to as “simulation.”  Simulation is so named because the machine “simulates” the treatment machine; much as a flight simulator imitates a cockpit.  The actual purpose of the simulation, however, is to allow us to establish a reproducible patient position and acquire images from which we can localize your target and devise a plan to treat it.  Almost all radiation treatments require you to simply lie on a table.  Many patients have seen a CT scanner; both the simulation and treatment tables are very much like those on a CT scanner.  There may be different devices we may create which will help you to lie comfortably on those tables in a very reproducible fashion.  They can even include masks and bean bags within which you will lie.  We also will use lasers to ensure you are lying flat and straight.

Next, we establish what is known as an “isocenter.” An isocenter is essentially one known point in space within your body.  A CT scan of the appropriate region is then obtained.  That CT scan is “registered” to the “isocenter” which we just established with those lasers.  From this CT scan and that isocenter, we can then use our computers to move our treatment volumes anywhere we want (up/down, in/out, left/right) within your body in order to very precisely identify the body parts in which we are interested. 

You may have heard about radiation oncology patients getting tattoos. Basically, a tattoo is a small drop of ink which we put on your skin and then gently flick with a small needle.  It leaves a tiny blue dot.  We use those tattoos to mark on your skin where the lasers define the isocenter (we use tattoos because magic marker would wash off!).  Usually it’s one on each side and one in the front.  Don’t worry, they really don’t hurt and they just look like a little blue freckle!  That whole planning process takes 30-40 minutes of your time.  The data we acquire will be what we use to then do all the planning for your treatment.  Depending on the complexity, this could mean a few hours to many days for us to get your treatment plan as perfect as it can be made.  Once your plan is derived, it undergoes rigorous additional checks of all the physics and other quality assurance measures. 

On your first day, you will be positioned on the treatment machine exactly as you were on the simulator.  Further imaging will be obtained on the treatment machine, with you lying in the exact treatment position.  Each and every treatment field will then be verified by one of our doctors before you are ever permitted to receive your first dose.  The actual radiation itself is just an invisible beam.  It’s just like when you get a chest xray.  Similarly, you don’t see the radiation, don’t feel the radiation, you won’t get hot, and you’re not going to be radioactive.  You will not pose any safety hazard to any friends nor family.

Beyond this point, the variations of side effects or likely experiences become too great from patient to patient to reasonably discuss in this format.  Rest assured, however, each patient will meet with one of our doctors at least weekly (or any time more frequently if you have a question or problem) to monitor your progress and address any issues as they arise.

Hopefully this little note will give you some idea at least of what getting your radiation therapy treatments underway will be like. We understand that “radiation” is often the least understood and therefore the most “scary” part of your entire journey.  We can’t promise that your course of therapy won't still be a bit spooky, but we can promise that we’ll be right there for you!