Intensity Modulated Radiation Therapy (IMRT)

Intensity-modulated radiation therapy (IMRT) is one of the advanced forms of high-precision radiotherapy that radiates high energy photons to destroy the cancer cells.  The device uses computer-controlled linear accelerators that deliver radiation doses to a tumor or surrounded tissues of the tumor. It also uses 3D imaging procedure that further helps by providing better three-dimensional image of the tumor during computed tomography (CT) or magnetic resonance images (MRI). The 3D view of the tumor assists the physician to plan for better calculation of the doses and intensity of the radiation therapy. The advantages of IMRT include

  • Application of higher and more effective radiation doses safely to the tumors with less side effects.
  • The combination of the multiple-intensity modulated fields allows control of the intensity of the dosages according to the requirement of the tissues.  
  • Potential reduction of treatment toxicity even during small dosages.
  • Restricts the development of the cancer cells and destroys the tumors.

Presently, the IMRT approach is most beneficial for treating prostate cancer or cancer of the head and neck or central nervous system. Sometimes it may be used for treating cancer of the breast, thyroid, lung, gastrointestinal or gynecological malignancies and certain sarcomas. Even for pediatric malignancies IMRT approach can be used.


The application of IMRT may require multiple or fractionated treatment sessions. The dosage and sessions of the IMRT depends on several factors including the type, location and size of the malignant tumor, doses to critical normal structures and the health of the patient.

The therapist positions the patient on the treatment table and marks the skin of the treatment area for accurate placement. Other imaging systems such as X-ray or CT scan may be used to check positioning and the marked location. Usually the treatment is given for 10 to 30 minutes.