Houston Methodist. Leading Medicine.
Houston Methodist. Leading Medicine


Intensity Modulated Radiation Therapy

Intensity Modulated Radiation Therapy (IMRT)

In March 1994, Houston Methodist Hospital became the first institution in the world to offer intensity modulated radiation therapy (IMRT) to patients.

Prior to IMRT, radiation technology used large portals, or windows, which offered no ability to view or define the shape of the target or normal tissues in 3-D. Treatment was usually delivered in an imprecise way, exposing healthy tissues to unnecessary radiation.

IMRT breaks those large windows into 40 small windows, which open and close as they rotate around the patient in an arc. This creates dose deposition and avoidance patterns described as “painting” or “sculpting” of the dose. The radiation oncologist can deliver precise and effective doses of radiation to irregularly shaped areas of the tumor, while avoiding healthy areas - even with the presence of normal body movements (such as breathing). This precision also minimizes side effects.

Houston Methodist has a number of machines, each with special capabilities, for IMRT. The Department of Radiation Oncology continues its tradition of innovation with technologies such as Anatom-e, a revolutionary mapping system developed in part and implemented by Radiation Oncology Chairman and Medical Director Dr. Brian Butler.

Intensity Modulated Radiation Therapy (IMRT) - Anatom-e System

Houston Methodist Hospital’s physicians are proud to have been involved in the development and implementation of a detailed anatomical mapping system known as Anatom-e. Houston Methodist was the first facility in the world to apply this cutting-edge system for cancer treatment.

The Anatom-e system’s interactive, highly detailed diagrams are used with CT scans and IMRT to streamline the diagnostic process and help target radiation therapy.

For example, since tumor cells spread through lymphatic (tissues and organs) pathways, defining the location of these pathways on an axial CT scan helps the radiation oncologist pinpoint the tumor location. The Anatom-e system maps out all the lymphatics in the human body. This helps to prevent the exposure of a larger amount of tissue than is necessary, preventing more side effects for the patient.