Modern methods of high-precision irradiation
Our Clinical Department is the only institution in the region that offers the entire spectrum of modern high-precision radiation (including all methods of electron and photon radiation [3D-CRT, IMRT/VMAT, IGRT, SGRT], head and body stereotaxis as well as brachytherapy and whole-body irradiation) at an internationally high level.
The basis of 3D-conformal radiation planning istomography of the body region in which the treatment is to take place. The radiotherapist defines and three-dimensionally reconstructs both the target areas - such as the tumor region - and the surrounding healthy tissue, which should be spared as much as possible, on these tomograms.
A medical physics expert then uses complex planning software to calculate the optimum alignment and limitation of the individual radiation fields based on the physician's dose specifications using the target dose in the tumor area and tolerance doses for normal tissue.
By applying several radiation fields from different irradiation directions during one irradiation session, the target area is "caught in the crossfire" and the surrounding normal tissue is spared.
In addition, the treatment beam is adapted to the shape of the target area to be treated using individually adapted multi-lamella collimators. In contrast to the previously common two-dimensional radiation planning (orientation on bony landmarks with standard settings - transfer of the CT information "subjectively and mentally"), with 3D-conformal radiation, the detection of the target area and the protection of the surrounding healthy tissue can be precisely reproduced and realized in every layer and every level of the body.
Intensity-modulated radiotherapy(IMRT) is a further development of 3D-conformal radiotherapy. In addition to the irradiation direction and shape of the irradiation field, the dose within the irradiation field can also be modulated. This is achieved, among other things, by dividing the individual radiation fields into many small "sub-fields" - so-called sub-segments. This may allow even better protection of the normal tissue surrounding the tumor, and the radiation dose in the tumor tissue may also be increased in order to improve the chance of healing.
VMAT (Volumetric Modulated Arc Therapy) is a form of intensity-modulated radiotherapy. This involves volume-modulated rotational radiation. The irradiation device rotates around the patient during irradiation and changes (=modulates) the shape of the irradiation field and the dose rate delivered at the same time with computer support. Irradiation is theoretically possible from any number of directions. The specified irradiation volume is recorded with high precision and surrounding organs and tissue are optimally protected, as with IMRT. The precision of this irradiation corresponds to that of IMRT. By rotating the irradiation device around the patient, the duration of irradiation can be shortened if necessary.
IMRT / VMAT radiation treatments are very complex to calculate, carry out and monitor, and require highly specialized personnel (physicians, medical physics experts, MTRAs) and state-of-the-art equipment. In addition, before the start of each treatment, the IMRT / VMAT plan created individually for each patient is checked for correctness before being applied to the patient (so-called "verification"). The above-mentioned circumstances also explain the considerable additional time required compared to conventional 3D-conformal irradiation. It should be noted that IMRT / VMAT is not actually superior to conventional 3D-conformal radiation in every individual case. For each patient, the technique that will benefit him/her the most is determined individually as part of the radiation planning process.
In the context of high-precision irradiation, it is essential that the patient is in exactly the same position during irradiation as during the tomography scans (computer tomography) as part of the irradiation planning. Therefore, tomography scans are performed again directly before the first irradiation on the irradiation machine itself (and then regularly at least once a week during the irradiation series).
This is possible because the modern radiation machines contain imaging technologies, for example for carrying out computer tomography. The current images are then immediately compared by the radiotherapist with the images from the planning phase and, if necessary, the positioning is optimized before the treatment. This ensures exact positioning during high-precision radiotherapy.
It is important to note that the images taken on the radiation machines are not of diagnostic quality and may therefore only be used for exact positioning.
As a rule, it is therefore not possible to make reliable statements about tumor progression on the basis of the images (diagnostic imaging by a radiologist is required for this).
Stereotactic radiotherapy uses image-guided positioning of the patient with millimeter precision and thus manages with very small safety margins around the planned target volume. This makes it possible to irradiate a relatively high single dose to a small area and thus destroy it in a targeted manner, comparable to the result of an operation.
The number and dose of the respective irradiations depends on the tumor entity and size. The procedure is used for various tumors in the brain, lungs or liver, among others.
Surface-guided radiation therapy (SGRT) uses a surface scanning system that enables continuous monitoring of patients by means of surface scanners and can compensate for small movements. The continuous observation and control of the patient's surface allows the patient to be positioned precisely and the correct position to be monitored during radiation without the use of additional X-rays. This technique is used, for example, for deep inspiration breath hold (DIBH) irradiation, which is primarily used for young patients with left-sided breast cancer with the aim of optimally protecting the heart and lungs.
In brachytherapy, a sealed radioactive source is used to irradiate very precisely and selectively "from the inside".
We offer the entire therapy spectrum.
Tumors are treated intracavitally, using natural body cavities (oesophagus, vagina, intestine) for temporary insertion of the radioactive emitter. We also offer interstitial techniques in which tumor tissue is irradiated directly from the inside through the insertion of hollow needles. In both cases, the adjacent normal tissue can be optimally protected.
Patients do not absorb any radioactive radiation and do not have to isolate themselves after treatment.
In the case of complex therapy procedures, treatment is usually carried out under anesthesia with admission to our ward.