What is the difference in External Beam
and IMRT????

Thanks

Patsy

Nothing - they are the same. External beam means primarily that the radiation source comes from outside (in contrast with brachytherapy which is "internal") such as a LINAC which delivers ionizing radiation (AKA Linear Accelerator).

IMRT stands for Intensity Modulated Radiation Therapy. It was introduced about 1994. It is a device that attaches to the primary collimator (beam forming device) of the LINAC and allows the beam to be broken into pencil sized beamlets (with a device called a MLC or Multi-Leaf Collimator) and these beamlets can be shaped and formed to conform to the actual tumor shape itself. It is even dynamic in that the beam can be continuously shaped during the treatment. An earlier form of this was called 3D conformal.

The advantage of IMRT is that there is less healthy tissue damage. Beam intensities can be moderated through radiation sensitive tissue areas. What this translates to is that often some salivary function can be spared. They can also save the thyroid in many cases.

An even earlier type of external beam radiation was XRT. It was developed in the 60's to replace Cobalt 60 machines which which could cause irreparable skin damage as the radioactive source aged and longer exposure times were required. The beam shaping is much less precise so a larger area is radiated as a result. In poorly differentiated cancers this may be the treatment of choice.

The very first type of external radiation was done with Cobalt 60 and the first successful treatment with external radiation for a head & neck cancer was in the late 1800's at the Curie Institue in Paris. Some foreign countries still use Cobalt 60 machines. It has been virtually eliminated as a treatment of choice in the US and replaced by the LINAC.

Proton Beam therapy was under development beginning in the early 90's, which uses a charged particle instead of ionizing radiation is the latest development in external beam radiation treatment modalities.

If we start our treatment at our Cancer Center they only use Ext. Beam, they do not have the IMRT yet (I justed asked that question today...boy have I got a lot to learn). I guess another reason to make sure that we go to a "Comprehensive Treatment Center" for the latest technique??? Maybe that is way the radiation doctor was jumping up and down to get all teeth removed?!?

Thanks for your explaination and wouldn't the IMRT be the perferred treatment?

Thanks for information is very much ppreciated.

Patsy

The right treatment is dependent on the location and type of cancer that you have. Gennerally IMRT can be used and would be preferred to avoid damage to healthy tissues as Gary indicated. However some treatments the IMRT may not help based on the location.
Again depending on where they need to treat the IMRT may help reduce some teeth exposure which may save some teeth. However if the teeth and jaw need to be treated, healthy teeth and gum a necessery to avoid problems latter if the teeth need to be extracted and then there could be healing of the gum problems which is why they are determining if you need to take some teeth out. I was lucky. My teeth (gums) were all 3+ probe reading and none needed to be extracted as well as the IMRT allowed minimim exposure of a large part of my jaw.

My husband's cancer is in the right tonsil.
he is T3N1MO.

Thanks for the info

PatsyJo,

I had general field radiation in 1989, before IMRT (and I probably wouldn't have been an IMRT candidate anyway, as my tumor was poorly differentiated). Still, I was able to keep all of my original teeth -- so having XRT doesn't necessarily mean lots of extractions. It's something that should be determined on a case by case basis, depending on the condition of the teeth and gums.

Cathy

If his cancer is differentiated, like mine was, he might be a candidate. I had no lymph node involvement however and that might make a difference. Actually many of the local and regional RT centers have been upgrading there LINACs for IMRT. I wouldn't let them pull my teeth unless they are in bad shape or he has gum disease. I kept all mine. The main reason they pull the teeth is to avoid Osteo Radio Necrosis (ORN) literally bone-radiation-death. It can happen about 10% of the time. I figured a 90% chance of NOT getting it didn't justify the quality of life issues, but once again the condition of gums & teeth is highly relevant. I have always seen a dental hygenist at least twice a year (more often now) and have taken really good care of my teeth. The "pull your all teeth" mantra seems to be standard policy but I personally think it is barbaric and uneccessary most of the time. Some people get ORN WITH all of their teeth pulled. They zapped a bunch of my lymph nodes as a precautionary measure so maybe they can treat him with IMRT. He will lose the parotid salivary gland behind the tonsil, but the other ones will make a comeback. It makes a huge difference. You will need to hurry and get a second opinion from a RO where they offer IMRT. RO's are not prone to recommend a treatment modality that they can't offer.

If I was in Texas, I would be going to MD Anderson anyway. They are one of the best. Be warned they probably won't touch once treatment is started so you must act fast.

This is one disease that is worth the effort to go the distance and get it right the first time. You're going to spend a little less than 2 monthes treating this - get the highest standard of care you can.
Institutions that call themselves "Comprehensive Cancer Centers" (CCC) or ones that call themselves "Cancer Centers" must meet specific NCCN and/or NCI standards of care. They will be on a list of institutions. I have posted this list many times - see if your cancer center is on the national list (try the NCI list for CC's)

Hello PatsyJo,

I had tonsil cancer also. Mine was a stage 4 NOMO. I had 33 treatments of IMRT 8 weeks after surgery even though my cancer was poorly differentiated. I had no teeth pulled as mine like Garys were in good shape. I do use Biotene toothpaste & Biotene mouthwash at least three times per day. Good oral care is a must after any type of oral cancer.
Good example of explaining the differences in radiation Gary. I learn something every time you post.

Best Wishes PatsyJo, Danny Boy

Ya'll are the best. Thanks for you continued support and help.

Our cancer is superficial fragments of invasive moderately differentiated squamous cell carcinoma focally invading skeletal muscle. ntraoperative diagnosis. Also the path. report indicated AFS1, right tonsil squamous cell carcinoma with at least microinvasion. T3N1M0. We are going to consult with new doctors. Still waiting on insurance answer from Loma Linda.

Whatever that all means...can someone spell it out for me?


Patsy

Patsy, what I spell out is that he has cancer. Pure and simple. Get to the best cancer you can afford and trust his doctors. They will know what to do.

Take care