TECHNOLOGICAL (R)EVOLUTIONS WILL BOOST PROTON THERAPY

A comprehensive white paper on technology trends explains how and why proton therapy is gaining increasing importance as a cancer treatment option. In part III, Spot Scanning or Pencil Beam Scanning (PBS) is put forward as a game-changing technology in the world of PT.

Spot scanning or Pencil Beam Scanning (PBS) is one of the technological improvements that will alter the market. Although it requires dependable equipment, it eliminates the need for additional tools, increases the number of clinical indications for proton therapy and contributes to minimizing the overall radiation dose.

It is important to point out that 90 to 95% of the patients so far have not been treated with this feature but rather with passive scattering, which only allows for the irradiation of uniform fields. This means that all clinical data so far is mainly based on less optimal use of proton therapy.

Increase number of clinical indications

PBS offers much more robust field characteristics, increasing the number of patients for whom proton therapy becomes the preferred treatment. Of course, this is an even more complex technology, making it more demanding for the equipment as well as the medical staff. Real-time human supervision becomes virtually impossible with PBS, because things move so fast during the treatment.

Passive scattering still makes it possible to oversee treatment prescription on a sheet of paper, allowing for verification on the spot. With PBS, up to ten thousand points are delivered to the tumor, each having its own specifications assembled in the treatment computer prescription file. There is no way to humanly verify if the system is doing as asked as these thousands of points are delivered at a tremendous speed for the purpose of limiting the time of treatment. The only way to do simultaneous verification is by having a second computer checking the computer that is feeding treatment specifications to the beaming equipment, so it requires very trustworthy equipment. As it nevertheless eliminates the need for patient-specific brass collimators to block the radiation shower from going beyond the treatment field, it saves on work hours to measure and produce these. This makes PBS a costsaving addition to any proton therapy installation.

Restrict the dose

Minimizing the overall exposure and radiation to healthy tissue has always been an important aspect of radiation therapy. This is where proton therapy offers a real advantage and has a huge clinical potential. A nuclear reaction making neutrons disperse through the body when sending proton beams inside is unavoidable, but the method of deliverance can make a big difference in volume and radius. Although the amount of neutrons is near-negligible compared to the protons delivered to the tumor, growing evidence that unnecessary radiation induces secondary cancer requires improved methods to avoid irradiation outside the field. These secondary cancers develop with a delay of decades, making them inconsequential in treatment of elderly people, but a major issue when it comes to treatment of youngsters. These findings are relatively recent, but make it essential to continue research regarding delivery methods, PBS being the most appropriate at the moment.

Read the complete white paper on technology trends http://goo.gl/AW5c7k