Pencil Beam Continued

Rapid Fire with Exquisite Precision
The Proton Therapy Center, which began treating patients with pencil beam in May 2008, was the first in North America and one of only three clinical centers in the world to employ this technology. Because pencil beam does not require any shaping devices the treatment is less time consuming than passively scattered beams, with most treatments only taking a few minutes. •
Using rapidly fired pulses, the pencil beam hits each planned spot within the tumor with a set dose of radiation, starting at the deepest layer and working in succession, layer by layer, until the whole tumor is covered. Lee estimates that a typical tumor will have between 1,000 to 2,000 separate spots arranged in up to 24 layers in a single pencil beam treatment. “We are able to maximize the protons generated and deposit more energy directly into the tumor,” Lee said.
THOUSANDS OF TARGETED PROTON BEAMS
Powerful scanning magnets direct thousands of ultra fine proton beams, one by one, toward a patient’s tumor. Intricate treatment planning allows for the protons to deposit their potent dose of radiation to the exact dimensions of the tumor, leaving nearby healthy tissue and critical structures untouched.

He notes that pencil beam could ultimately be applied to any tumor site where proton therapy is used, including cancers of the prostate, eye and head and neck. It is an especially attractive future option for solid tumors in children, who are generally more sensitive to the adverse effects of radiation. “Without the apertures, pencil beam deflects fewer neutrons into healthy tissue, which have been shown to increase the risk of second malignancies in young, still growing patients.” M. D. Anderson has treated over 40 patients with pencil beam to date.

Have a good Wednesday.

Today is Tea Party Day. Enough is enough already.

Blessings,
Rick