I guess it's being used at Loma Linda U. Anybody know layman info about it? I tried reading the tech info but I don't understand alot of it. Something about protons instead of ? in the radiation beam. Appears to have a much tighter field than IMRT.

This one is best answered by Gary, our local radiation imaging and treatment guru....

IMRT and IMPT are very similar. They are both Intensity Modulated and capable of being programmed to attack the exact shape of the tumor. The "R" stands for radiation the "P" for proton.

There is a significant distinction between standard radiation treatment and proton therapy. If given in sufficient doses, conventional radiation techniques will control many cancers. But, because of the physician's inability to adequately conform the irradiation pattern to the cancer, healthy tissues may receive a similar dose and can be damaged. Consequently, a less- than-desired dose is frequently used to reduce damage to healthy tissues and avoid subsequent unacceptable side effects. The power of protons is that higher doses of radiation can be used to control cancer while significantly reducing damage to healthy tissue and vital organs.

Proton Beam Therapy, as the name implies, uses protons to fight cancer. Protons are stable, positively charged subatomic particles with a mass 1800 times that of an electron. These characteristics allow the proton's dose of radiation to be controlled to an exact shape and depth within the body.

The main difference between protons and X-rays is based on the physical properties of the beam itself. Protons are large particles with a positive charge that penetrate matter to a finite depth based on the energy of the beam. X-rays are electromagnetic waves that have no mass or charge and are able to penetrate completely through tissue while losing some energy. These physical properties have a significant bearing on the treatment of patients.

The photons or electrons used in conventional radiation therapy deposit most of their energy in the tissues they pass through before reaching the tumor and often deliver radiation beyond the targeted tumor to surrounding normal, healthy tissue. Although advanced techniques such as intensity-modulated radiation therapy can reduce the exposure of healthy tissue to radiation, with photon radiation therapy, the delivery of at least a small amount of radiation to these structures cannot be avoided.

Protons are energized to specific velocities, and these energies determine how deeply in the body the protons will deposit their maximum energy. Since proton beams are heavier than their conventional counterparts, they can be delivered more precisely and prescribed to cover the entire tumor. The result: proton beams can treat tumors deep within the body while producing minimal or no side effects in surrounding tissues.

M.D. Anderson feels good enough about it to invest 125 million in a whole new treatment center for it, scheduled to open in 2006.

If I had to do it over again, I would put this high on my list of potential treatment therapies to investigate. Over 33,000 patients have been treated with this technology since 1990 when it was introduced. Unfortunately only a few institutions are offering it at this time.

The treatment machine is over 200 tons and uses voltages as high as 250 mEV (million Electron Volts)(compared to 20mEV for a high powered LINAC) 6-12 mEV being typical for head & neck cancers. The rotating gantries are 35' in diameter and dwarf conventional LINACs which weigh in at a paltry 9 1/2 tons.

I believe that at least one member of the board was treated at LLUMC.

Long term data is still being developed for survival rates. LLUMC is preparing a 10 year study of prostate cancer patients. Like IMRT, IMPT was developed for prostate cancer and found a niche in the head & neck realm (among many others).

My personal feeling is that IMPT will eventually become the gold standard.

For those wishing further information type "proton therapy" in Google and you will access all of the articles I cited and quoted from. "IMPT" was not a very good search term.

Some of my sources were MD Anderson, Harvard University, LLUMC and Optivus. Used without permission.

Thanks Gary! Maybe I'll be taking a trip to sunny Cali!! I just don't know what to do. I've been in the consumer electronics industry for 20 some years & I've always been a trailing edge technology guy for my own personal stuff; best value, tried ,tested & proven, closeouts, refurbished goods, etc. This is kinda the same situation except that good enough might not be! My survival & quality of life are at stake! Like my 13 year old daughter would say, "Do ya feel me?" I'm glad everyone here speaks english & not the instant message language of the young generation!

One question. Can these two treatments be used to an area if you have already had general beam radiation to that area? I am under the impression that the IMRT can be used.

Eileen

Eileen, Loma Linda UMC 1-800-776-8667

Eileen,
that's a VERY good question. It would seem logical to me that it could be used in an area previously treated. IMRT can used sometimes to retreat but there are limitations.

Erik, I think it would be worth the trip...

hi,

i didn't pay much attention to details, but i recall that i was treated with both radiations at Hopkins in 2001... i don't know about the IM part of it.

i had the normal proceedure for the full 35 treatments... and for treatments from about 25-35 the proton machine was added. i was told that it was being used to kill cancer cells in muscle area without damaging my spinal cord.

this machine was mainly being used for folks with breast and prostate cancer. i didn't meet other head&neck folks in that waiting area. so
stupid me thought this was a low tech, not a hi tech machine - since not many of us head&neckers were using it.

i wonder if there is a 'low tech' proton machine?

cu,
larryb

I am having soon what they call at the hospital "boosters" till the end of treatment, (from #26 onwards). What are they, are they what we are talking about here?

Cheers!

tizz

Tizz,
"boosters" usually means that they are giving you "extra" radiation in specific targeted areas. Most folks have about 5000 cGy of radiation, "full boost" ups the ante to 7,000 cGy. If you have a late stage (like I did) they will always give you the full boatload.

Larry,
I did a fairly comprehensive search on Johns Hopkins site and could not find any reference to PBT or therapeutic protons. If you are treated on one of these you would know it. They would probably send you to counseling just to deal with the sheer size of it. This piece of equipment requires it's own unique building.

Proton therapy had been limited to physics centers until now. And like most new technologies, the prototype is a very expensive endeavor. However, more institutions have plans for proton therapy facilities in the near future including Harvard University at Massachusetts General Hospital. There are proton therapy facilities in Canada, Japan, Germany, Russia, South Africa, Switzerland, France and England.

Currently there are only 2 proton treatment centers in the United States.

The world's first hospital-based proton center opened in 1990 at Loma Linda University Medical Center in southern California. Loma Linda has treated more than 8,000 patients with proton beam radiation therapy in the last 12 years, mostly men with prostate cancer.

In 2000, the Northeast Proton Therapy Center at Massachusetts General Hospital opened and is treating cancer patients. MPRI will become the third proton center and will put the nation's midsection on the proton map and in the forefront of advanced medical treatment.

The future for more regional proton centers also looks bright. In the southwest, the highly respected cancer program at M.D. Anderson Cancer Center in Houston will add protons to its treatment mix. As will the University of Pennsylvania Medical Center in Philadelphia, and the University of Florida's Shands Medical Center in Jacksonville.

"After a decade of proving at Loma Linda that proton therapy actually works, its becoming a mainstream cancer treatment option," said Leonard Arzt, executive director of the National Association for Proton Therapy. "The public has become knowledgeable about the benefits of proton therapy. That's why we've seen a demand for more regional proton centers. People want to limit their travel time and stay closer to home."

Source: http://www.proton-therapy.org/pr19.htm

Yes Larry, I'm pretty sure there is a "low tech" proton treatment. I had the same thing almost three years ago for the last several treatments. I recall the Radiation Oncologist specifically telling me about the different type of radiation and that it had very controllable depth of penetration. The difference here is that the areas to be treated were defined by blocks of Lead not by computer controlled "Fingers".

Proton charged particles, as Gary said, have a very predictable penetration depth based upon the energy settings of the system. Lower energy (power), lower depth of penetration, Higher power, greater depth of penetration.

I AM EDITING MY POST. upon more reading, I realize that it is UNLIKELY that my treatments included PROTON radiation, so I'm going to have to call my RAD ONC DOC and ask what it was he did at the end of my treatments ???

Wish I had known about these machines 3 years ago, it might have saved my voice box.

Glad to see Penn is getting one, just in case I go down for a third time.

Thanks for all the useful information.

Eileen