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 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.
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]
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.