Intensity-modulated radiation therapy (IMRT)

Intensity-modulated radiation therapy (IMRT) is an advanced method of 3-D-conformal radiation therapy. In particular, in the treatment of tumors having a concave shape, in the bends of which there are healthy tissues sensitive to the effects of radiation, radiation therapy for a long time could not be fully applied. Intensity-modulated radiation therapy (IMRT) several years ago opened new prospects in this direction.

IMRT is a method of treatment that allows distributing optimally the dose of radiation throughout the tumor and ensure the most sparing effect on adjacent tissues. The irradiation field is divided into many smaller sections, each of which is irradiated separately and at different intensities. High-energy radiation can be targeted specifically on tumor tissue. The organs within the risk region can be bypassed to within a millimeter.

This was made possible due to multi-sheet collimators (MLC). Such a collimator consists of an adjustable diaphragm with separate mobile lead plates that are placed in front of the radiation source and can be located both in the trajectory of the rays and outside it. Thus, the intensity of the irradiation dose is modeled within the irradiation field and the formation of therapeutic radiation. While the radiation source moves around the tumor, the diaphragm of the collimator is set by the computer on the contours of the tumor in the appropriate direction of irradiation.

Due to this, particularly high doses of radiation can be used.

This method has special advantages in radiotherapy for prostate cancer, as it provides for more reliable protection of organs with a special susceptibility to radiation, such as the intestine and bladder. Radiation therapy with modulated intensity is also effective in the treatment of tumors in the head, neck and thorax.

IMRT for prostate cancer

Differences in IMRT and 3DCRT of prostate cancer