Radiation Medicine Today

The term radiation medicine (radiotherapeutics) encompasses a number of procedures and applications that deal diagnostically and/or therapeutically with ionizing radiation. This includes radiology, radiation therapy, and nuclear medicine (areas in which physicians can train to become specialists); in a broader sense, it also includes – more in the area of research – radiation biology, which deals with the biological effects of all forms of radiation.

Nuclear Medicine

In nuclear medicine, radioactive substances and nuclear physics techniques are used for functional and localization diagnosis of organs, tissues, and systems. Short-lived open radionuclides, i.e., radioactive atomic nuclei that decay under radiation of α-, ß-, or γ-radiation, are used in the treatment.

One nuclear medicine procedure that is used particularly frequently in practice is scintigraphy, which is used to examine organ functions – especially frequently on the thyroid, kidneys, bones, lungs, and heart muscle. Other nuclear medicine methods include positron emission tomography PET, the medical assessment of radioactivity that has entered the body in radiation accidents, and – as a form of radiation therapyradioiodine therapy and radionuclide treatment.

Radiology

In radiology, disorders are detected and treated using ionizing radiation, nuclear physics, and sonographic techniques. In addition to classic X-rays, the procedures include computed tomography, magnetic resonance imaging and spectroscopy, as well as the various ultrasound examinations (sonography).

Contrast agents such as insoluble barium salts, iodine compounds, air or carbon dioxide are added to better visualize organs or to delineate them from surrounding tissue. Contrast media are used primarily for examinations of the stomach and intestines or for imaging vessels. X-ray examinations without contrast agents are known mainly from images of the lungs (thorax), abdomen (abdomen), skeleton and bones, or from breast cancer screening mammograms.

Diagnostic radiology and interventional radiology

A distinction is made between diagnostic radiology and interventional radiology, which are minimally invasive therapeutic procedures performed using imaging techniques. These include, for example, the dilatation of vascular stenoses or the insertion of a catheter under fluoroscopic control (angiography), the treatment of acute bleeding, or puncturing with a cannula to obtain tissue or fluid.

Diagnostic and interventional measures often merge smoothly – for example, a tissue change can be detected during an ultrasound examination and simultaneously removed and thus treated.

Radiotherapy

The treatment of diseased tissue, especially malignant tumors, with ionizing radiation is called radiation therapy. Along with surgery (operations), chemotherapy and hormone therapy, it is one of the mainstay treatment methods for cancer. The basis of radiation therapy is the knowledge that tumor tissue is much more sensitive to radiation than healthy tissue. The genetic structure of the tumor cells is damaged by the high-energy forms of electromagnetic radiation or particle radiation, and the tumor is thus destroyed.

Unlike chemotherapy, in which the drug is distributed throughout the body, most forms of radiation therapy have a localized effect. However, there are also radioactive drugs (radiopharmaceuticals) that are distributed throughout the body via the bloodstream and contain substances that accumulate in the tumor due to special properties. For example, radioactive iodine is used to treat thyroid cancer, and strontium-89, which is chemically similar to bone minerals, is used to treat bone metastases.

In some cases, the radiation effect can be enhanced by drugs or other procedures that make tumor tissue more radiosensitive.