In External Beam Radiotherapy, transverse and longitudinal dose measurements are taken by a radiation detector in order to characterise the radiation beams from medical linear accelerators. Radiation therapy (or radiotherapy) is the medical use of Ionizing radiation as part of Cancer treatment to control Malignant Typically, an ionisation chamber and water phantom are used to create these radiation dose profiles. An ionization chamber is a device used for two major purposes detecting particles in air (as in a Smoke detector) and for detection or measurement of Ionizing radiation Water is used due to its tissue equivalence. Water is a common Chemical substance that is essential for the survival of all known forms of Life.
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 dose profiles. Dose measurements taken along the z direction create radiation dose distribution known as a depth-dose curve.