Pencil-beam scanning

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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[edit]

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[edit]

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[edit]

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[edit]


  1. ^ Blake GM, Parker JC, Buxton FM, Fogelman I (October 1993). "Dual X-ray absorptiometry: a comparison between fan beam and pencil beam scans". Br J Radiol. 66 (790): 902–6. doi:10.1259/0007-1285-66-790-902. PMID 8220974.
  2. ^ Khan, Faiz M. (2010). The Physics of Radiation Therapy. ISBN 9780781788564.
  3. ^ page4
  4. ^ "03-30-09 - Advances in Proton Therapy, Pencil Beam Technology Reach Patient Care - MD Anderson Cancer Center". Archived from the original on 2011-03-03.
  5. ^ "The PSI Proton Therapy Facility". Archived from the original on 2002-01-06.