How Proton Radiation Works
A Layman’s Version
Proton therapy does not use light rays like conventional radiation.
Proton radiation uses positively charged particles taken from hydrogen gas. You take hydrogen gas and push a little bit into an injector. Then it gets hit with the equivalent of a lightning bolt of electricity. That splits the atoms.
A hydrogen atom is simple in that it has a proton in the middle and one electron floating around the outside. The electric charge splits the negatively charged electron from the positively charged proton.
The electrons get eliminated and the protons are kept and this is done every two seconds. About 20 billion protons are created at a time.
The protons are pushed into a big aluminum pipe (called a synchrotron) and they start circling around super fast. The protons get up to 60 percent of the speed of light that’s several times around the earth in a second.
The high-energy protons then proceed down the beamline to the gantry, where the patient is treated. In the case of M. D. Anderson there are four gantries.
Then a specialist manipulates and shapes the positively charged proton beam so it is the exact same shape as the target (tumor) it’s designed to hit. The invisible beam penetrates the skin, leaving no mark (sometimes the skin will appear a bit darker at the entry point almost like a tan), and explodes right inside the target.
The protons have the ability to penetrate to various depths within the patient’s body where they produce sharp “peaks” of energy. To make them usable clinically, the proton beam passes through a “modulator wheel”, which has stairsteps of different thickness. This creates a spread out “mesa” of energy, or a “box” of radiation that can be used for radiation therapy. That box is shaped in 3D with the brass aperture and the acrylic compensator and conforms to your anatomy.
One guy said it very well: ‘I didn’t know I was sick. I didn’t know if I was being treated. And I don’t know if I’m well, but what the heck. Proton therapy treats many kinds of cancer. It is not used for bone cancer or cancer that has spread into the bones. It has not been used on cervical cancer yet.
The above extracted from descriptions written by Loma Linda Hospital and M. D. Anderson
