How does IMRT work?
Conventional radiation therapy techniques use radiation beams of uniform intensity to destroy the tumor cells in a patient’s body. Although the tissues outside the radiation field can be protected by shaping the radiation beam to encompass the tumor, a column of tissue from the beam’s entrance to its exit is indiscriminately irradiated. Using the fact that not all tissue reacts to radiation in the same way, IMRT varies radiation intensity across the field. The radiation beam can also rotate around the patient, sending beams from a more favorable angle and location. By cross-firing the tumor with these beams of varying intensity from all possible angles and locations, a uniform dose of radiation is delivered to the tumor, while the effects on the sensitive structures surrounding the tumor are minimized. During the IMRT treatment planning process, a computer-generated planning system acquires information about the location of the tumor and its surrounding structures from a patient’s CT i
