THREE DIMENSIONAL CONFORMAL RADIATION THERAPY (3D-CRT)
Tumors are not regular- they come in different shapes and sizes. Three-dimensional conformal radiation therapy, or 3D-CRT, uses computers and special imaging techniques to map the size, shape and location of the tumor. Computer Assisted Tomography (CT or CAT scans), Magnetic Resonance Imaging (MR or MRI scans) and/or Positron Emission Tomography (PET scans) are used, individually or by fusion, to create detailed, three-dimensional representations of the tumor and the surrounding organs. This uses a multi-leaf collimator (MLC) to frame precise radiation beam windows to a targeted area. The multi-leaf collimator is a device with a series of computer-controlled leaf-like rods. Because the radiation beams are very precisely directed, nearby normal tissues receive less radiation and are able to heal quickly. Hence, this treatment is superior to the conventional 2D treatment. The time taken for this planning is between 1-3 days.