Intensity Modulated Radiotherapy (IMRT)
Intensity modulated radiotherapy, available at Martha Jefferson Hospital since 2006, takes advantage of recent innovations in treatment planning software and computer controlled linear accelerators with multileaf collimators to provide extremely conformal radiotherapy. IMRT planning starts with delineation of the target as well as the normal tissues. The radiation oncologist determines the dose to the target and the dose limitations for the normal structures. Then inverse treatment planning is done, in which the computer runs through thousands of iterations to arrive at the optimal treatment that meets the planning criteria. IMRT involves the use of varying intensities of hundreds of small radiation beams (beamlets) to produce more precise dose distributions than possible with 3D conformal radiotherapy. This technique permits the delivery of higher tumor doses with increased sparing of normal tissues which has resulted in improved cure rates for prostate cancer as well as head and neck cancer. It also has markedly reduced the radiation side effects for patients with cancers of the head and neck, anal canal and rectum.