9. The Physics of Protons



The cyclotron came from IBA, a Belgiun company and world leader in radiation equipment.





The cyclotron has four gaps that accelerate the protons.




The beam line is the pipe that goes from the red supermagnet on the left through the smaller blue magnets. The blue ones organize the beam. The red one bends it.




This is the control room for the engineers that monitor and test the protons twenty-four hours a day every day (even on weekends when patients aren't being treated.)









Behind the scenes this huge sixty-ton gantry turns along with the nozzle on the patient side of the wall. It remains a puzzle to me why it must be so big.











Here is a photo of a whole gantry in Heidelberg, Germany.







This gantry for charged ions is also in Heidelberg, the largest such equipment in the world (670 tons). Note the size on the man in the bottom of the photo.















This brass aperture is used to conform the double scattered beam to the shape of the prostate. The newer technology, pencil beam scanning, doesn't require an aperture as it lays down a series of spots which can be controlled individually.





This chart shows the superior benefits of pencil beam scanning (PBS). The previous technology, double scattering, comprises the bar at the bottom where it says "Standard Indications." This and the next chart show why PBS represents the treatment of the future, which is available today!






PBS increases the number of cancers treted by proton therapy from 20% to 80%.






The two technologies for proton therapy work quite differently. The top one scatters the beam into a field of protons which are onformed with an aperture to hit the target. Note the blue area in fron of the target in which peripheral health tissue gets a full dose of protons.

PBS lays down a series of dots and so does not affect the healthy tissue to the same extent.



This illustration is not in the book. It more clearly shows how double scatterig works. This is the technology used by the majority of proton therapy centers built before 2014, and even some newer ones.






This bonus illustration shows how PBS works. I guess I should have put these in the book. Maybe in a future edition. You can see how the spots build up in layers, hence the term "scanning."







This photo shows me on the treatment table, taken from down by my feet. My right arm hangs off the table. You can see the close proximity of the snout (on the left) to my thigh. Note the laser beam that indicates proper alignment. The range shifter screen sits on the front of the snout, right next to my arm, with a bar code to identify it. Again, photos like these are what distinguish this book from others about proton therapy.





You may also be interested in our list of proton centers around the United States, found at:

Return to Photos.

Return Home.