In external beam

Radiotherapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...

, transverse and longitudinal dose measurements are taken by a radiation detector in order to characterise the radiation beams from medical

linear accelerators A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beam ...

. Typically, an

ionisation chamber The ionization chamber is the simplest type of gas-filled radiation detector, and is widely used for the detection and measurement of certain types of ionizing radiation, including X-rays, gamma rays, and beta particles. Conventionally, the term ...

and water phantom are used to create these radiation dose profiles.

Water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

is used due to its tissue equivalence. Transverse dose measurements are performed in the x (crossplane) or y (inplane) directions perpendicular to the radiation beam, and at a given depth (z) in the phantom. These are known as dose profiles. Dose measurements taken along the z direction create radiation dose distribution known as a depth-dose curve.

References

{{Reflist Cancer treatments Radiation Radiation therapy Medical physics

See also

References