From: scerir (scerir@libero.it)
Date: Tue Aug 12 2003 - 14:08:10 MDT
While still at a very early stage, a small company
in the US is turning to antimatter as a potential
form of particle therapy. PBar Medical is currently
using antiproton beams at CERN to investigate the
effects of antiprotons in biological material.
Antiprotons exhibit the same Bragg peak as protons,
but when they meet protons and neutrons at the treatment
site, they annihilate to produce gamma rays and high energy
particles that cause further damage to cancerous cells.
Antiprotons might therefore be much more effective than
protons, although this remains to be demonstrated.
- Physics World March, 2003 p12 -
"For antiprotons no data on dose profile vs. depth in biological medium
exist and we can therefore not determine the absolute absorbed dose for
the different slices. Furthermore, the requested beam time is not
sufficient to measure the dose profile. Instead, we introduce a new
quantity, the biological effective dose ratio (BEDR), which will allow
us to extract meaningful biological data without absolute dosimetry.
Because antiprotons behave nearly identical to protons in the plateau
region we can use standard dosimetry methods to determine the relative
plateau dose."
http://doc.cern.ch//archive/electronic/cern/preprints/spsc/public/
spsc-2003-020.pdf
"Just as with protons or heavy ions, antiprotons can be used to deliver
radiation to the body in a controlled way; however antiprotons will
exhibit additional energy deposition due to annihilation of the
antiprotons within the body. The slowing down of antiprotons in matter
is similar to that of protons except at the very end of the range beyond
the Bragg peak."
http://doc.cern.ch//archive/electronic/cern/preprints/spsc/public/
spsc-p-324.pdf
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