IMRT is a relatively new radiotherapy delivery technique that was developed in the early 1990's with widespread implementation by 2000. IMRT is the logical progression of 3DCRT with the primary goal of improving radiation dose conformality around irregularly shaped tumor target volumes. IMRT creates many small radiation beams of differing intensity that allow for planning of highly complex radiation dose distributions around curved, doughnut shaped and other non-geometric tumor target volumes. The widespread implementation of IMRT was made possible in large part due to the dramatic increase in computing speed and efficiency of the 1990's. IMRT integrates 3DCRT with advanced computerized treatment planning software and advanced treatment delivery techniques that allow for radiation beam intensity modulation. This combination results in radiotherapy treatment that approaches the best possible delivery of radiotherapy.
IMRT for Mesothelioma
Radiotherapy of malignant pleural mesothelioma (MPM) presents significant challenges in planning and delivery. In particular, the large size of the treatment area (encompassing the entire thoracic cavity on the affected side) and the close proximity of several critical organs (heart, opposite side lung, liver and kidneys) necessitate the use of a technique that can conform radiation doses tightly to the tumor target volume. IMRT can potentially be used to provide improved local tumor control while still sparing nearby critical tissues. However, very close interaction is required between the thoracic surgeon, radiation oncologist and the radiation physicist for proper implementation of IMRT for radiotherapy of MPM after surgery (EPP). The thoracic surgeon must provide detailed guidance to the radiation oncologist and radiation physicist as to the nature and extent of the post-surgical disease site to be treated with radiation.