J Korean Med Assoc.  2011 Nov;54(11):1172-1178.

Introduction of intensity modulated radiation therapy

• Ahn YC

Abstract

The role of radiation therapy (RT) in cancer management has grown remarkably during the past few decades. For successful RT, the most important factor is highly conformal radiation delivery focused to the tumor-bearing region while minimizing the surrounding normal tissue damage. RT has evolved from 2-dimensional and 3-dimensional techniques to intensity modulated RT (IMRT) along with the development of computer science and mechanical engineering. IMRT is a special form of 3-dimensional conformal RT techniques, by which the intensities of radiation coming though the beamlets are modulated so that conformal radiation dose distribution around the tumor-bearing region is achieved. IMRT has been covered by the Korean health insurance system since July 2001. The basic principles and process of IMRT are introduced.

Keyword

Intensity-modulated radiation therapy; Radiotherapy

MeSH Terms

Fibrinogen
Insurance, Health
Fibrinogen

Figure

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  Figure 1 Intensity modulated radiation therapy using the linear accelerator with multi-leaf collimator system. The shape and the intensity of radiation coming through the multi-leaf collimator are modulated to achieve a highly conformal radiation dose distribution around the target region, while limiting the radiation doses to the surrounding normal organs below the acceptable tolerance limits.

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  Figure 2 The design of tomotherapy. The radiation intensity is modulated while the megavoltage X-ray tube is continuously rotating, and the patient's couch is moving. CT, computed tomography.

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  Figure 3 An example case of nasopharynx cancer treated by tomotherapy. The radiation doses to the gross tumor volume (GTV), clinical target olume (CTV), and the normal organs (parotid glands, brainstem) are optimized.

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