How is radioactivity used in medicine

Applications in medicine, technology and research

When doctors examine internal organs, archaeologists date scrolls or computer manufacturers manufacture processors, they often resort to methods that are based directly on the findings of hadron and nuclear physics.

The social relevance of hadron and nuclear physics extends far beyond basic research. Their methods have long since found their way into medical technology, materials research, production, energy and safety technology and numerous other scientific and economic areas. For example, accelerators are used to produce tailor-made radionuclides for examining practically all human organs - an aid for medical diagnostics that can hardly be overestimated.

Scanning technique of irradiation

Radionuclides are used in biological research, for example to make processes and structures in cells visible. New imaging methods are based on the direct visualization of nuclear physical processes, such as positron emission tomography (PET) and nuclear spin or magnetic resonance tomography (MRT). Both procedures have become indispensable in medical diagnostics.

New methods in medicine

For the irradiation of tumors that are difficult to treat, increasingly protons and, for a few years now, carbon ions are used. The advantage over the usual gamma rays is that these particle beams only release the majority of their energy at the end of their range in the tissue. The range depends on the energy and can therefore be adjusted with the help of the accelerator so that the particles in the tumor are stopped and destroy it. This protects the surrounding healthy tissue.

By deflecting the beam and varying its energy, the volume of the tumor is completely and precisely scanned. Researchers at the GSI Helmholtz Center for Heavy Ion Research have developed this grid technique using magnetic fields. Since 1997, around 440 patients with tumors mainly on the base of the skull have been irradiated with carbon ions. The procedure has been in routine use at the Heidelberg Ion Beam Therapy Center (HIT) since 2009. About 1300 patients can be treated there annually.

The Nebra Sky Disc

Archeology, cultural history and art

Radiocarbon dating with carbon-14 has been used routinely for a long time to precisely determine the age of dead organic substances over a period of many thousands of years. Especially the development of accelerator mass spectroscopy makes it possible today to analyze the smallest samples and thus to date archaeological objects, grave finds such as the glacier mummy Ötzi, works of art or objects of cultural significance such as the Turin shroud in a non-destructive manner.

Proton and ion beams make it possible to obtain information about materials and their chemical composition without taking samples. The non-destructive ion beam analysis makes it possible, for example, to identify layer sequences of art-historical or archaeological objects, to gain knowledge of the pigments used or to make structures hidden in deeper layers visible.

Materials research and solid state physics

By irradiating with high-energy particles - protons, neutrons, ions - microscopic and macroscopic material properties can be changed. That is why ion beam processes have become indispensable in our technologically highly developed society and are routinely used in numerous industrial areas. In particular, they are indispensable for producing materials with tailor-made properties.

This includes the doping of semiconductor elements, the hardening of metallic materials or the high-precision machining of solid surfaces. Ion beams can be aligned very precisely and their energy can be precisely adjusted. That is why they are also an important tool for the synthesis of nanostructures for novel applications such as electronic, optical, optoelectronic or sensor components.

Space technology in a practical test

Simulation of cosmic rays

Accelerator facilities also offer unique possibilities for simulating cosmic particle radiation. Radiation-insensitive components and electronic components are required for space missions, for example for reliable data transmission. These devices are tested in radiation experiments in the laboratory by bombarding them with ions such as those found in cosmic rays. For manned space travel, systematic studies on biological cells are also indispensable in order to assess the risks and radiation damage in long-term missions in advance.

Earth sciences, environmental physics and climate research

The age of rocks, sediments, meteorites and the earth itself can be precisely determined with the help of long-lived radioactive nuclides. Erosion rates and processes in the atmosphere can be tracked over a wide time range by analyzing specific radionuclides such as beryllium-10, aluminum-26 and manganese-53. With the help of accelerators, mass spectrometry has been developed into a highly sensitive technology that allows the detection of tiny concentrations of trace elements or pollutant molecules in the earth, water and the atmosphere down to a relative concentration of well below 10-15, that's the equivalent of one atom or molecule for one trillion of other particles. In Lake Constance, for example, the method could still be used to detect alcohol, even if only a single glass had been poured into it.

For the climate discussion, findings that are gained with nuclear physics methods are very important. In mighty ice cores in the Arctic and Antarctic, the isotope ratio of oxygen-16 and oxygen-18 is used to precisely analyze the mean annual temperature over a range of many thousands of years. The data also make it possible, among other things, to determine long-term changes in solar radiation and their possible effects on the earth's climate in the past.