External beam radiation is used in all stages of prostate cancer
Whereas external beam radiotherapy was long considered a poorer alternative to prostate removal, today, thanks to state-of-the-art technology, very high radiation doses can be delivered while sparing the neighboring organs as much as possible, since the load on healthy tissue can be calculated precisely before treatment begins.
Modern radiotherapy
Today, external radiation therapy is only performed with modern linear accelerators. A linear accelerator is comparable to a giant X-ray tube, with which a high-energy photon and electron radiation can be artificially generated. This radiation is capable of destroying rapidly growing tumor tissue. In order to ensure that the beam destroys the tumor in a very targeted and thus gentle manner, elaborate techniques are used to produce as few side effects as possible for the patient.
Conformal 3-D irradiation
3-D conformal irradiation of a tumor is the standard therapy currently used in Germany. In this process, a 3-D model is used to calculate an irradiation plan in the computer with special software, in which the individual irradiation fields are individually adapted or collimated to the patient's anatomy with a so-called Multi Leaf Collimator (MLC). Such an MLC consists of 120 individual lead lamellae, which can shape the beam individually and adapt (conform) it to the position of the tumor with millimeter precision. This can significantly reduce side effects.
Intensity Modulated Radiation Therapy (IMRT)
IMRT is a further development of 3-D conformal radiotherapy. In this innovative technique, the lead lamellae (MLC) can also move in and out of the beam path during irradiation and thus modulate the intensity of the radiation dose within the irradiation field. This technique has great advantages, especially in the irradiation of prostate cancer, as organs that are particularly sensitive to radiation, such as the intestine and the urinary bladder, can be spared even more.
Image Guided Radiation Therapy (IGRT)
Another new innovative technique of modern radiotherapy is "Image Guided Radiotherapy" (IGRT), with which 3-D imaging (Cone Beam CT) can be generated during the ongoing irradiation and thus the accuracy of the irradiation fields can be checked even more precisely. Thus, an extreme precision of irradiation can be achieved, which leads to a significantly lower side effect rate but also to an improved effect at the same time. This method offers great advantages, particularly in the irradiation of prostate carcinomas. Before starting the irradiation, 3 gold marker seeds are implanted in, which are detected by the Cone Beam CT and a deviation, no matter how small, can be corrected immediately.
Breath-guided irradiation (4-D irradiation)
When irradiating organs or tumors that can move during breathing, this technique makes it possible to detect the target region only when it is in a specific breathing position. This "breath gating" is particularly used in the irradiation of breast cancer to spare the lungs and in the treatment of lung tumors that move during radiation therapy.
