Breath gating

What is respiratory gating?

Respiratory gating is a term used to describe a special method of radiotherapy for cancer. This involves delivering radiation only during certain phases of your breathing, either during inhalation or exhalation. It is therefore also referred to as breath-controlled radiation.

Together with surgical removal of the cancerous tissue and chemotherapy, radiotherapy represents one of the most important treatment approaches in cancer therapy. It uses ionizing radiation to inhibit the growth of cells. As malignant cancer cells are characterized by uncontrolled and invasive growth, it is primarily used to treat malignant tumours.

Because irradiation can also harm healthy cells, it is important to precisely delimit the area of radiation to protect surrounding tissue from unwanted radiation exposure. Although modern imaging techniques make it possible to locate the position of the tumor more and more precisely, it is not possible to prevent all movements of the tumor during the radiotherapy session.

There are two main factors that influence this: firstly, the patient's own movements and secondly, the displacement of the organs due to breathing. By providing patients with proper information and offering the right positioning tools, it is generally possible to prevent changes in body position. Respiratory gating was developed to also take into account the respiratory displacement of the organs.

Special methods and computer programs can measure the position of the organs during inhalation and exhalation. Radiation is only delivered during the breathing phase during which the organ can be most effectively targeted without exposing the neighboring tissue to high levels of unwanted radiation.

Irradiation with respiratory gating: preparation and planning

Before any radiation treatment can take place, the precise volume and exact position of the tumor have to be determined. Based on this data, the so-called radiation plan is created, which also records the radiation dose used.

A range of imaging techniques are used to determine the exact dimensions of the tumor tissue, usually by means of a CT scan. When performing breath-controlled radiation, the patient's breathing is recorded additionally. Further technical equipment like an infrared camera or special body scanners may also be necessary.

As the process of planning continues, the breathing position is determined in which the tumor tissue can be optimally exposed to radiation. This is why the preparatory examinations are always carried out several days before the first radiotherapy session.

For which types of tumors can breath gating be used?

Breath gating is mainly used for tumor locations that would subject nearby organs to high doses of radiation if conventional radiotherapy methods were used. Above all, organs that are very sensitive to radiation must be spared. They include nerve tissue or intestinal loops, for example.

The organs which are displaced to a particularly large extent are the lungs themselves as well as organs located in the chest and abdominal cavity close to the diaphragm. Breath-guided radiotherapy can therefore be used mainly for breast and lung cancer as well as for cancers of the liver, stomach or kidneys.

How does breath-controlled radiotherapy work?

The procedure for breath-controlled radiotherapy differs between breath gating with and without a breath command. In essence, the procedure of breath-controlled radiation is similar to that of conventional radiotherapy.

Patients are kept in a precisely defined position. Then a CT scan is carried out again to verify the data set out in the radiation plan. Additionally, the patient's breathing is also recorded again. It is necessary for breathing to be detected for the entire duration of the irradiation.

If a breath command is given, the patient is asked to inhale as deeply as possible. Patients are advised to practise this at home beforehand. The irradiation will then only take place during this phase. Once the patient can no longer hold their breath, the radiation stops automatically.

In the case of breath gating without a breathing command, patients breathe in and out calmly. Again, irradiation is only carried out in a defined breathing position. The treatment session is slightly longer due to the interruptions, but usually lasts no more than 30 minutes.

What are the benefits of respiratory gating?

Respiratory gating offers a number of advantages for organs that are strongly displaceable by breathing and border on radiation-sensitive tissue. To ensure that these organs are irradiated with a sufficient dose during the various phases of respiration, there is always a safety margin. Breath-controlled radiation allows this safety margin to be significantly reduced around the relevant site to ensure better protection of the adjacent tissue.

As breath gating leads to a more targeted irradiation, it also reduces the risk of late complications due to unwanted radiation exposure to surrounding organs. The incidence of acute side effects is also reduced with this procedure.

What are the associated risks and side effects?

As with almost every invasive treatment method, breath-controlled radiation involves certain risks. There is a differentiation between acute radiation reactions and chronic radiation damage.

Acute radiation reactions may include skin and mucous membrane irritation of the area exposed to radiation. Short-term nausea, vomiting and severe fatigue may also occur. Radiation exposure of the bone marrow can cause disorders of blood formation. Radiation-induced pneumonia can develop in the lungs.

Chronic radiation damage is accompanied by a functional limitation of different organs such as the thyroid gland, bone marrow or reproductive organs. Another risk is fibrosis, which refers to a change of healthy tissue into connective tissue and the appearance of further tumors is possible, too.

Which doctors and clinics specialize in breath gating?

The treatment of cancer diseases demands interdisciplinary cooperation between specialists from oncology, radiotherapy and radiooncology.

Being diagnosed with cancer always represents a major challenge for patients. This is why patients wish to be able to rely on the expertise and experience of their treating physicians.

Our aim is to help you find the right practitioner for your condition, which is why we have carefully evaluated all the doctors listed here and approved them as highly competent. They are all experts in their respective fields with extensive experience in the planning and administration of breath-controlled radiotherapy. Take advantage of their experience and schedule your first appointment with one of our specialists quickly and easily.