IMRT, RapidArc
Intensity-modulated radiotherapy - IMRT
Intensity-modulated radiotherapy (IMRT) is the most modern radiotherapy technique, with which the radiation dose is precisely adapted to the region to be irradiated ("target volume"). This procedure enables the surrounding tissue to be spared as much as possible. It is the further development of 3-dimensionally planned radiotherapy (3D radiotherapy), which is also considered standard therapy. IMRT is typically carried out over 5-7 radiation fields (but possibly significantly more) from different directions. In contrast to conventional irradiation techniques, the intensity of the individual radiation fields is varied (modulated). This modulation is achieved using lead discs that adapt to different areas of the target volume during irradiation and are then irradiated with a higher or lower intensity. This technique is of great importance for complex-shaped tumours, especially tumours located in the immediate vicinity of organs at risk (such as the heart, lungs, small intestine, large intestine, spinal cord or bladder). Using this technique, the radiation can be optimally adapted to these organs at risk. This ultimately leads to a significantly reduced exposure of the organs at risk compared to previous conventional radiotherapy techniques. As a result, the likelihood of serious side effects occurring during treatment is significantly reduced compared to the past. As a result, the total dose of radiotherapy could be significantly increased for many target volumes, while still reducing the risk of severe late effects. These higher radiation doses have significantly improved the chances of cure for various types of cancer such as prostate cancer, lung cancer, head and neck cancer and certain brain tumours. For example, the risk of severe chronic inflammation of the bladder and rectum has been significantly reduced in the case of prostate cancer, while the late effects of pronounced dry mouth in the case of head and neck tumours, for example, are now much less pronounced. If you have any questions, please contact Dr Thamm.
Volumetric intensity modulated arc therapy ("VMAT")
RapidArc irradiation
The so-called "Volumetric intensity modulated arc therapy" (product name: "RapidArc" technique) is a further development of the IMRT described above, in which the radiator head rotates around the patient while continuously adjusting the irradiation field and dose rate. The target volume is irradiated with pinpoint accuracy by means of precise lamella adjustment. By using 360° irradiation angles and a variable dose rate that is individually adapted to the patient for each irradiation angle, the target volume can be irradiated at an even higher speed than with IMRT. Of particular importance for patients are the very short treatment times with the same irradiation efficiency. This rapid arc radiotherapy is used for around 70-80% of all patients and tumour entities. Due to the advantages mentioned, this procedure has replaced standing field IMRT in many cases. The faster application is particularly advantageous for patients with head and neck tumours or brain tumours who are irradiated in a mask position. However, patients also benefit considerably in the case of symptomatic complaints such as pain from bone metastases. Standing field IMRT, on the other hand, offers advantages for patients with breast cancer, for example, because it leads to better lung and possibly also heart protection than rapid arc radiotherapy. With the most modern techniques, complete radiotherapy can be carried out in less than 60 seconds when radiating prostate carcinoma. If you have any questions, please contact Dr Thamm.
The 360° rotation angle can be seen at the top left. The high dose area is coloured red. In particular, the bottom left and bottom right images show how the dose drops steeply within a few millimetres to the rectum (green/blue colour) and the urinary bladder.
