Can an operation be carried out in space?

How does radiation therapy work?

Biological effect

X-rays can damage and kill cells. However, the cells of our body are used to small amounts of X-rays because they hit us constantly (e.g. from space). However, if a certain amount is exceeded, the cells can no longer fully repair the damage caused by the X-rays. This "repair limit" is usually relatively low in cancer cells, i.e. cancer cells can tolerate less X-rays than healthy cells in the body. If the amount of radiation is properly “portioned” (technical term: fractionation), radiation can be used successfully for cancer treatment. The cancer cells are killed, but the healthy tissue can fully recover.

What has to be irradiated?

Tumors spread to the surrounding area; the tumor is almost always larger on a microscopic examination than it appears to the naked eye. These microscopic settlements respond well to X-rays. Even if a tumor has been completely removed (shown in the picture by the black line), small tumor cell nests may have remained in the area. Then post-irradiation makes sense. Even if no surgery is performed, it is always necessary to also irradiate the area around the tumor, which appears healthy, with a low dose.

Success through radiation therapy

Radiation therapy is often used in combination with an operation, usually after the operation, to destroy microscopic remains of the tumor. Radiation therapy can improve the chances of success of the operation and can often replace a major operation. With breast cancer, for example, small breast-conserving surgery plus radiation is more effective against cancer than radical removal of the breast. Radiation often also offers an alternative to surgery and is gentler than major surgery (e.g. for prostate cancer) or enables organs and functions to be preserved (e.g. for larynx cancer or bladder cancer). And radiation can also achieve a cure in some situations in which it is no longer possible to control the disease through surgery and / or chemotherapy.

Radiation therapy technique

The irradiation takes place mostly from the outside ("external irradiation"). For a precise irradiation one needs strong X-rays that can penetrate deeply and also penetrate bone. Normal X-rays that are used for imaging cannot be used. The device is therefore a Electron linear accelerator (see picture) used.

The X-rays are generated in the radiator head (focus). The device can rotate around a virtual point in space (isocenter). The position of the isocenter (exactly 1000mm away from the focus) is marked by laser systems. During the irradiation, the patient is placed on the couch, and the couch is then positioned in such a way that the geometric center of the target area (this was therefore calculated beforehand with computer planning) coincides with the isocenter. The device always “looks” at the center of the target area. In this way, the target area is always precisely irradiated.

During the treatment, the patient remains alone in the treatment room and is monitored with cameras and microphones.

Today, the radiation is calculated by specially trained physicists and engineers using planning programs. Due to the progress in computer technology, even very complicated radiation techniques can be calculated quickly and reliably; Nevertheless, we always estimate several days for irradiation planning in order to be able to calculate the best irradiation in each case. The end result is a 3D radiation plan that shows the doctor not only the distribution of radiation in the target area, but also the radiation exposure of all other important organs.

The illustrations show parts of the treatment plan. In this case the patient had an inoperable tumor in the base of the tongue (throat) with extensive lymph node metastases on both sides of the neck. The treatment was a combination of radiation and simultaneous chemotherapy to intensify radiation (radiochemotherapy). In these cases, a particularly complicated technique (so-called IMRT = intensity-modulated radiotherapy) is always used for the irradiation. The colors show doctors and physicists the distribution of radiation. The radiation dose is automatically calculated on every healthy organ (recognizable from the dose-volume histogram at the top right). So the treatment is very precise and safe.

The “real exposure time” (i.e. the time in which the device irradiates the patient) is around 1-2 minutes for each daily radiation session. The rays themselves cannot be felt by the patient. With the technology used today, the risk of complications is very small. Radiation therapy is often a gentle alternative to cancer surgery and can also be used in elderly patients or patients with a high risk of anesthesia.

If you have any further questions, we, the clinic's doctors, technologists and physicists, are at your disposal.