Getting Zapped with Protons - Good if You Have Cancer
Roopinder Tara posted on September 25, 2017 |
Proton beam therapy is on the rise. Advanced Oncotherapy compact design aims to reduce cost of lifes...
 Shooting bad guys with ray guns may be science fiction. Zapping tumors with proton beams, however, is real. 
 Figure 1 -  Engineers that matter. Neil Parker, Quality and Improvement Manager, Advanced Oncotherapy. Picture from LinkedIn.

Engineers that matter. Neil Barker, Quality and Improvement Manager, Advanced Oncotherapy. Picture from LinkedIn.

Proton beam therapy can be very effective—and create far less collateral damage— than X-ray therapy, says Neil Barker at Autodesk’s Accelerate 2017 conference, where Barker is the keynote speaker. 

This is due to the proton beam’s unusual ability to stop and expend almost all of its energy exactly at the tumor, a phenomenon known as the Bragg Peak effect.

This effect gives protons an apparent improvement over X-rays that unleash their destructive energy almost immediately under the surface of the body, whether or not a tumor is there, and continue to ionize cells until they exit the other side. Since proton beam’s energy is localized, much more of it can be applied to kill the tumor, while minimizing damage to healthy tissue.


Figure 2- Bragg Peak effect shows the destructive energy of a proton concentrates at the tumor. (Picture courtesy of Advanced Oncotherapy).
Bragg Peak effect shows the destructive energy of a proton beam concentrates at the tumor. (Picture courtesy of Advanced Oncotherapy).
 Figure 3- Proton beams only go so deep, while X-rays will go through the whole body. Picture from ProTom International.
Proton beams only go so deep, while X-rays will go through the whole body. Picture from ProTom International.

 Size Matters 

When an engineer says size matters, it’s not a joke. Barker, a chartered engineer (UK’s version of a PE) says a multi-treatment room proton therapy center can cost hundreds of millions of dollars and take up the area of a football pitch (soccer field). That’s small compared to the Large Hadron Collider (at CERN), a 27 kilometer (17 mile) tunnel beneath the French-Swiss border.

But not small enough.

Advanced Oncotherapy means to reduce the size of and modify proton therapy centers so that the cost of treatment becomes more comparable to that for X-ray radiotherapy. 
Figure 4 - Instead of a circular accelerator, Advance Oncotherapy will be using a linear design. It takes more energy to make a proton go in a circle. A linear design will not require supercooling, also making the system less expensive to build and use. The speed of the proton increases with each unit added to the line. Three units, as shown, give the protons enough kinetic energy to penetrate to tumors deep inside the body, such as in the abdomen and the chest. Picture from Redshift.
Instead of a circular accelerator, Advanced Oncotherapy will be using a linear and modular design. A linear design will not require cryogenic cooling, which the more compact current systems may require,making the system less expensive to build and use. The maximum energy of the proton beam increases with each accelerating unit that is added. The configuration shown gives the protons enough kinetic energy to penetrate to tumors deep inside the body, such as in the abdomen and the chest. Picture from Redshift.com.

The maximum energy of the proton beam and, consequently, the depth to which it can penetrate and treat tumours, depends on the number of accelerating units in the linear accelerator.

“A kinetic energy of 230 megaelectron volts typically corresponds to a treatment depth of 32 cm. This energy is sufficient in most cases and more units can be added as required.”

Figure 5 - The patient is precisely positioned with the help of a numerically controlled, 5-axis seat. Not shown is how the patient may be restrained. “The degree of fixation varies,” says Neil Barker of Advanced Oncotherapy.
The patient is precisely positioned with the help of a numerically controlled, 6-axis seat. 

 An interview with Neil Barker, conducted at Accelerate 2017, is soon to follow.

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