As I understand it, there are radiation treatments that do
use non-photon particles.  "Proton beam" and "very-high energy
electron therapy" do that.  There is some argument, and some
evidence, that these therapies have just the benefits you
suggest they might.

Why aren't more doctors using them?

I'm not sure of the answer to that, but I'm guessing there are
a number of factors.  Perhaps:

1. They're relatively new and doctors are conservative.
If high energy xrays are known to work, a lot of doctors
may not want to try something else until more proof has
accumulated.  Since cancer can recur years later, doctors
often want to see evidence that patients treated with the
new therapies are in good shape 5, 10, or 15 years down
the road as well as immediately after treatment.

2. Radiation oncologists don't yet have a lot of experience
with the new techniques.  Like all of us, doctors like
to stick with what they know.

3. Equipment is very expensive.  When a clinic already has
a million or two's worth of xray equipment, they may not be
eager to go buy a few million's worth of something else - at
least not until the old stuff breaks down or is shown to be
inferior.

But there are places where you can get these kinds of newer
treatments.  Keith Lundy on this newsgroup had proton beam
therapy and is satisfied with his treatment.  There may have
been some others here too.

   Alan

During my investigation phase I spoke to a radiation oncologist who
explianed it this way. External beam radiation requires a series of
treatments over several days. Therefore, the target accuracy must be
repeatble to a high degree. This repeatable accuracy is not possible
since the prostate gland is connected to other tissues and has some
degree of freedom to move around. Chances of hitting the exact same
spot for each treatment are not good. Chances of hitting something else
with the beam are possible. For example, you could damage the rectal
wall, bladder, or the urethra. This is one of the primary reasons I
decided against it. For radiation treatment, this doctor recommends
only seeding.

Pete

hi dave - since this was one of my fields of skill in the military,
maybe i can put it in easy to understand terms.  so here goes.

radiation energy is absorbed by water.  this is one of the tools that
they test the farmer's grain with, to know of the moisture content and
how much to pay him.  

this is also why you can't see through clouds because the cloud absorbs
the energy level and the droplets of moisture act like a prism and will
alter or deflect the radar's beam and spread  it out for a weaken return
echo.

but a long time ago, they found out something interesting.  that is when
RF energy is passed through a body, due to the frequency that it
operates in - the x-band which is 9500 megacycle - the rapid shifting of
the energy caused the molecules inside the body to vibrate and generate
heat - much like rubbing your hands together.

amana was one of the first manufactures to make use of this
characteristic and build the first microwave oven.  and that is the
theory behind microwave ovens today.  the energy of the microwave causes
the molecules in the product to vibrate so fast that they generate the
heat and cook themselves.  it doesn't make any difference whether it is
popcorn or a steak.

now, using this principle for wide spread beam radiation,  they want to
get the body to generate the heat needed to kill the pca cells without
killing the host.  because of this type of theory, it is important to
understand that radiation kills the good cells as well as the bad cells.

the use of the proton beam radiation is a bigger particle.  and because
of that reason,  they now have better control on the deep of penetration
in the human body

conventional radiation is giong to pass through the body and drop some
of it's energy shaking up the molecules, whereas, proton beam will spend
all of it's energy and stop inside the body.  the end result.  more
power where you need it and a better kill.

hope this all makes sense.

~ curtis

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
http://community.webtv.net/PALMER_ENT/doc