Radiation Therapy (IMRT)
Intensity-Modulated Radiation Therapy and how is it used?
radiation therapy (IMRT) is a mode of radiotherapy that utilizes
computer-controlled x-ray accelerators to deliver precise radiation doses to a
malignant tumor or specific areas within the tumor. The radiation dose is
designed to conform to the three-dimensional (3-D) shape of the tumor by
modulating—or controlling—the intensity of the radiation. In the IMRT planning
process, treatment planning computers use "inverse planning" techniques to
maximize the dose to the target and minimize the dose to sensitive structures.
In the process, the multileaf collimator (MLC) is set to a multitude of sizes
from different beam angles to obtain the required dose distribution. After the
plan is approved, it is sent to the treatment machine where the linear
accelerator will deliver the planned treatment.
The radiation physicist ensures the linear accelerator delivers the precise
radiation dose and that computerized dose calculations are accurate. Treatment
sessions are similar to convention treatments and usually take between 15 and