How Does Pencil-Beam Scanning Treat Cancer?

Get answers to frequently asked questions about pencil-beam scanning

Scripps Health Proton Therapy.

Get answers to frequently asked questions about pencil-beam scanning

Scripps Proton Therapy Center offers the most advanced proton radiation technology available. It’s also the only facility of its kind in San Diego and the only facility in the nation to have pencil-beam scanning in all treatment rooms.

Learn the benefits of proton therapy pencil-beam scanning, a highly precise form of cancer treatment.

What is pencil-beam scanning?

Pencil-beam scanning is an advanced and targeted way to treat cancerous and non-cancerous tumors. The technology allows proton therapy to be delivered in a single, narrow proton beam that is about 4-5 millimeters in diameter. Pencil-beam scanning deposits the radiation dose, layer-by-layer, like a painter’s brush strokes. It forms to the specific shape of a tumor and can be adjusted for intensity to achieve the desired dose distribution.

What are the benefits of pencil-beam scanning?

Due to its accuracy, pencil-beam scanning is ideal for complex cancers, in which the tumor is located near critical structures. Because of the precision, healthy surrounding tissue can be spared, reducing the risk of secondary cancers or other complications common to other forms of cancer treatment .

How is pencil-beam scanning therapy delivered?

Pencil-beam therapy is delivered through three main components – a cyclotron, a beam transport system and a gantry.

  • Cyclotron
  • The proton beam is generated in a cyclotron, which is approximately 6 feet tall by 9 feet wide, and weighs approximately 90 tons. This is where a plasma stream is created using hydrogen and oxygen. The protons are then extracted and accelerated to approximately 100,000 miles per second, which is about half the speed of light.
  • Beam transport system
  • A series of electromagnets — magnets that employ electric current to produce their magnetic fields — steer the proton beam with a vacuum line from the cyclotron to each treatment room.
  • Gantry
  • Of the five treatment rooms at the center, three are equipped with a gantry. These three-story devices guide the proton beam to the delivery nozzle, allowing the patient to be treated from different angles.

Why choose Scripps?

As the only proton treatment center in San Diego, Scripps Proton Therapy Center’s team of physicians and physicists has more than 90 years of combined experience treating patients with cancer. The center is a state-of-the-art facility and features the most advanced proton radiation therapy technology available to treat cancer.

Scripps Proton Center also offers the latest generation of imaging technology and is the first center in the nation to place those tools within the treatment center itself. This results in greater convenience for the patient as it allows the medical team to perform all treatment planning in one site.