Pencil-beam scanning explained

Pencil beam scanning is the practice of steering a beam of radiation or charged particles across an object. It is often used in proton therapy, to reduce unnecessary radiation exposure to surrounding non-cancerous cells.

Ionizing radiation

Ionizing radiation photons or x-rays (IMRT) use pencil beam scanning to precisely target a tumor.^[1] Photon pencil beam scans are defined as crossing of two beams to a fine point.

Charged particles

Several charged particles devices used with Proton therapy cancer centers use pencil beam scanning.^[2] The newer proton therapy machines use a pencil beam scanning technology.^[3] This technique is also called spot scanning.^[4] The Paul Scherrer Institute was the developer of spot beam.^[5]

Intensity Modulated Proton Therapy

Varian's IMPT system uses all pencil-beam controlled protons where the beam intensity can also be controlled at this small level. This can be done by going back and forth over a previously radiated area during the same radiation session.

See also

• Pencil (mathematics)
• Pencil (optics)
• Radiation treatment planning
• mean free path
• Monte Carlo method for photon transport
• Hybrid theory for photon transport in tissue
• Diffusion theory
• Monte Carlo method
• Varian Medical Systems

Notes and References

1. 8220974 . 66 . 790 . Dual X-ray absorptiometry: a comparison between fan beam and pencil beam scans . October 1993 . Blake GM, Parker JC, Buxton FM, Fogelman I . Br J Radiol . 902–6. 10.1259/0007-1285-66-790-902 .
2. Book: The Physics of Radiation Therapy. 9780781788564. Khan. Faiz M.. 2010.
3. http://www.accessdata.fda.gov/cdrh_docs/pdf10/K100766.pdf page4
4. Web site: 03-30-09 - Advances in Proton Therapy, Pencil Beam Technology Reach Patient Care - MD Anderson Cancer Center . www.mdanderson.org . dead . https://web.archive.org/web/20110303060629/http://www.mdanderson.org/newsroom/news-backgrounders/03-30-09-advances-in-proton-therapy-pencil-beam-technology-reach-patient-care.html . 2011-03-03.
5. Web site: The PSI Proton Therapy Facility . radmed.web.psi.ch . dead . https://web.archive.org/web/20020106111302/http://radmed.web.psi.ch/asm/gantry/scan/n_scan.html . 2002-01-06.