Pencil beam scanning (Medical physics)

Ionizing radiation

Ionizing radiation photon

Photon

In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...

s or x-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

s (IMRT) use pencil beam scanning to precisely target a tumor. Bone scan densitometry uses a fan scan system that replaces a pencil beam system. Radiation treatment planning

Radiation treatment planning

In radiotherapy, radiation treatment planning is the process in which a team consisting of radiation oncologists, radiation therapist, medical physicists and medical dosimetrists plan the appropriate external beam radiotherapy or internal brachytherapy treatment technique for a patient with...

has pencil beam scanning as one of its modalities. mean free path

Mean free path

In physics, the mean free path is the average distance covered by a moving particle between successive impacts which modify its direction or energy or other particle properties.-Derivation:...

is involved in IMRT planning. Also used in Monte Carlo method for photon transport

Monte Carlo method for photon transport

Modeling photon propagation with Monte Carlo methods is a flexible yet rigorous approach to simulate photon transport. In the method, local rules of photon transport are expressed as probability distributions which describe the step size of photon movement between sites of photon-tissue interaction...

. Another three sources are: Hybrid theory for photon transport in tissue

Hybrid theory for photon transport in tissue

Hybrid Theory for photon transport in tissue uses the advantages and eliminates the deficiencies of both the Monte Carlo method and the Diffusion Theory for photon transport to model photons traveling through tissue both accurately and efficiently....

which is a combination of Diffusion theory and the Monte Carlo method

Monte Carlo method

Monte Carlo methods are a class of computational algorithms that rely on repeated random sampling to compute their results. Monte Carlo methods are often used in computer simulations of physical and mathematical systems...

all using, in part, pencil beam scanning. Photon pencil beam scans are defined as crossing of two beams to a fine point.

Charged particles

Several charged particle

Charged particle

In physics, a charged particle is a particle with an electric charge. It may be either a subatomic particle or an ion. A collection of charged particles, or even a gas containing a proportion of charged particles, is called a plasma, which is called the fourth state of matter because its...

s devices used with Proton therapy

Proton therapy

Proton therapy is a type of particle therapy which uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. The chief advantage of proton therapy is the ability to more precisely localize the radiation dosage when compared with other types of external beam...

cancer centers use pencil beam scanning. The newer proton therapy machines use a pencil beam scanning technology.
This technique is also called spot scanning. The Paul Scherrer Institute

Paul Scherrer Institute

The Paul Scherrer Institute is a multi-disciplinary research institute which belongs to the Swiss ETH-Komplex covering also the ETH Zurich and EPFL...

was the developer of spot beam.

Ionizing radiation

Charged particles

See also