What is meant by "intensity modulation"? Pg. 430
In the traditional external beam photon radiation therapy, most treatments are delivered with radiation beams that are of uniform intensity across the field (within the flatness specification limits). Occasionally, wedges or compensators are used to modify the intensity profile to offset contour irregularities and/or produce more uniform composite dose distributions such as in techniques using wedges. This process of changing beam intensity profiles to meet the goals of a composite plan is called intensity modulation.