In General

One of the trends noted at the American Society of Radiation Oncology (ASTRO) 2018 meeting was the move towards pencil beam scanning.

The move towards pencil beam scanning is driven by research showing the advantages of pencil beam scanning over passive scattering.

What is pencil beam scanning?

Pencil beam scanning is the most precise form of proton beam delivery. Using an electronically guided scanning system and magnets, pencil beam scanning delivers proton therapy treatment via a proton beam that is just millimeters wide.

Advantages of pencil beam scanning

With pencil beam scanning, beam position and depth are able to be controlled, allowing for highly precise deposition of radiation to be delivered in all three dimensions of the tumor.

Due to the superior dose sculpting and high beam efficiencies, pencil beam scanning delivers lower doses of radiation to critical structures and healthy tissue than other proton beam delivery methods. This reduces side effects and improves long-term outcomes for patients and improves the patient’s quality of life.1, 2

Another important consideration is that unlike other methods of beam delivery, pencil beam scanning does not require the use of patient-specific or field-specific devices (apertures, compensators) in the delivery of proton therapy treatment. This eliminates treatment delays, reduces treatment time, reduces costs, increases flexibility in treatment delivery, and reduces patient exposure to secondary radiation produced when the beam hits a device.

Interested in learning more about pencil beam scanning? Download our factsheet and check out our clinical efficacy page. The clinical efficacy page includes research published between 2016 and 2018 that underscore the benefits of proton therapy for certain cancer patients. The majority of the studies employ pencil beam scanning.


1 W P Levin, H Kooy, J S Loeffler, T F DeLaney. “Proton Beam Therapy.” Br J Cancer. 2005 Oct 17; 93(8): 849–854. 

2 University of Pennsylvania School of Medicine. “Studies point to clinical advantages of proton therapy: Studies demonstrated lower toxicities, positive survival outcomes for lung, pancreatic and spine cancers.” ScienceDaily. Published online 2015. Oct 19.