Proton TherapyBy: Alanna Kirkpatrick, Michael Mai, Corbin Osborne, and Matt Street

Purposey To compare the effects of proton

therapy and X-ray therapy for treating Cancer patients. y To compare the effectiveness of proton therapy with children vs. adults

Backgroundy 1919 Ernest Rutherford discovered the existence of the y

y y y y

proton. 1945- American physicist Robert R. Wilson, who worked with nuclear bombs, suggested that proton beams could be used as a treatment method. 1954 in California, a research particle accelerator was used for the first treatment. 1988- FDA approved proton therapy for treating patients. First hospital to use proton therapy was in California in 1990 Today there are 7 proton therapy centers and 5 under construction.

Costy Average cost per treatment ranges from $30K to

$40K

Example Cyclotron Facility

How it worksy High dose of concentrated beam of proton is shot a the y

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cancer tumor. When the protons come near the orbiting electrons of the atoms that make up the tumor the protons can pull off the electrons from their orbits effectively ionizing the atom. It damages the DNA and keeps the bad cells from spreading. The healthy cells can rebuild but the cancer cells can not. Both X-ray and Proton therapy work on the principle of selective destruction but proton therapy is more effective.

The Difference

Traditional X-Ray affects everything in its path which causes damage to healthy tissue cells, the beam also continues through the patients body. Proton therapy has better precision and provides a lower dose to healthy tissue. This allows higher doses to be delivered to the tumor.

The Difference Cont.Spare normal tissue, organs at risk, or previously irradiated tissue. Eliminate exit dose. Minimize entrance dose. Minimize integral dose.

Aiming for the tumor

SOBP- Spread out Bragg peak

PhysicsHigh velocity protons give up very little of their ionization energy. First slowed by electronic stoppingslowing down due to the inelastic collisions of electrons (coulomb force) When it slows down it has more time to grab an electron which damages the cell through ionization.

How Cyclotrons WorkCyclotrons accelerate charged particles using a highfrequency, alternating voltage (potential difference). A perpendicular magnetic field causes the particles to spiral almost in a circle so that they re-encounter the accelerating voltage many times.

Pros and Cons+Cyclotrons have a single electrical driver, which saves both money and power, since more expense may be allocated to increasing efficiency. +Cyclotrons produce a continuous stream of particles at the target, so the average power is relatively high. +The compactness of the device reduces other costs, such as its foundations, radiation shielding, and the enclosing building. -Cant accelerate into relativistic speeds.

Bethe formula

describes the energy loss per distance travelled of swift charged particles (protons, alpha particles, atomic ions, but not electrons) traversing matter

Conclusiony Proton therapy was approved by the FDA in 1988

for the treatment of cancer y It cost between $30K and $40K y Proton therapy is better than x-ray therapy because it is a more precise dose and does not damage other healthy cells in its path.