Intensity-modulated radiotherapy (IMRT)

What is IMRT?

All cancer therapies are based on precise destruction of tumor cells while sparing adjacent organs and healthy tissue. Intensity-modulated radiotherapy allows the application of a larger radiation dose through optimized focussing of the radiation beams to the tumor.

How does IMRT work?

Three-dimensional mapping of the target area is based on CT imaging. Once the tumor has been defined, surrounding tissues are marked during planning with computed tomography so that they can be spared. Subsequently, the required radiation dose is calculated by a specialized medical physicist. Unlike conventional three-dimensional radiation therapy, this is followed by further segmentation of the target area into sub-areas. This way, central tumor areas can be exposed to more intensive radiation, while peripherally located structures close to sensitive adjacent organs receive a lower dose of radiation. By this spatial segmentation and temporal fractionation over several sessions, a uniformly high dose is delivered to the tumor mass, while minimizing irradiation time and damage to vital organs. Optimizations of IMRT have also been made since then: The VMAT method (volumetric intensity modulated arc therapy), employs a radiation source which rotates around the patient while permanently adjusting the target area as well as the beam intensity.

When to choose intensity-modulated radiotherapy?

Incorporating CT imaging in advance for accurate therapy planning requires a tremendous amount of time. This method is only advantageous for tumors that are located close to very sensitive tissues when compared to conventional, directly image-guided planning of the irradiation area. This is particularly worth the effort and expense when dealing with the face, head and neck region, breast cancer and lung tumors, as well as prostate and gynecologic cancers.

Which advantages are present?

Because the radiation dose diminishes significantly towards the margin of the tumor tissue, it is possible to effectively irradiate even complex structures, for example concave tumor sites, while preserving nearby tissues. This allows for optimal protection of the heart and large blood vessels in the chest. As normally the tissues are displaced with each breath the patient takes, the irradiation can be synchronized with the respiratory rhythm. Intensity modulated radiotherapy has become the gold standard also for irradiation of organs which are sensitive to excessive destruction as potency or viability of germ cells may be affected, for example the internal genital tract. With regard to irradiation of the face and head, the most important aspect is to protect the sensitive salivary glands from a high energy exposure to reduce frequent side effects of conventional methods, including xerostomia (dry mouth). Besides the genital organs, other tumors in the lower abdomen involve the rectum, another sensitive structure where optimal protection can help reduce side effects that impair the quality of life, such as bothersome incontinence.

Which doctors and clinics are specialists for the field of intensity-modulated radiotherapy?

If you're in need of a doctor, you expect the best medical care possible. So of course patients are curious to find out what clinic to go to. As there is no objective way to answer this question and a legitimate doctor would never claim to be the best, patients must rely on a doctor's experience.

Let us help you find an expert for your condition. All listed doctors and clinics have been reviewed by us for their outstanding specialization in the field of intensity-modulated radiotherapy (IMRT) and are looking forward to your inquiry or wish for treatment.