Radiation protection in medicine: There is still lots of work to be done

Medical radiation is a double-edged sword: from a diagnostic perspective, it allows us to look inside the human body, while it can also be used to treat cancer. However, each use exposes patients to radiation, which in turn can pose health risks and should, therefore, be avoided. This is where the European joint research program MEDIRAD comes in.

In this interview with COMPAMED-tradefair.com, Prof. Christoph Hoeschen explains how patients would benefit from a more customized radiation dose, describes what radiation protection in medicine could look like and details how MEDIRAD plans to support this issue.

Prof. Hoeschen, what does radiation protection in medicine entail for patients and physicians?

Prof. Christoph Hoeschen: There are actually three pillars. First, there are the structural protections. For example, radiation therapy requires a therapy room that is shielded with thick concrete walls. Thin protective lead layers that are installed on the walls like wallpaper are sufficient in diagnostic radiology. Second, there is personal protective equipment that is worn on the body such as lead aprons for example.

Having said that, the most effective measure is an optimal parameter setting for the radiation-based diagnostic technology and radiation therapy based on height, weight, age, gender, and pre-existing conditions of patients. Especially in diagnostics, the knowledge of the necessary parameters is still in its infancy, because the new product developments of device manufacturers also always offer new setting options. This also always goes along with weighing the benefits and risks of radiation-based diagnostics to avoid unwarranted examinations.

This is also a focus of the European research project MEDIRAD.

Hoeschen: The 33 partner institutions of MEDIRAD focus – among other things – on the different aspects of CT exams of the lungs and thorax. We want to assess how much the image quality changes if the parameters are modified and subsequently infer early recommendations for optimizing exams.

What patients warrant extra caution when they are exposed to radiation?

Hoeschen: Needless to say, everybody should receive equal protection. However, children and pregnant women require extra caution. You also have to consider whether patients have preexisting medical conditions pertaining to organs you want to examine and illustrate. In these cases, radiation could cause further damages or changes.

Generally speaking, it is difficult to make a statement about the dangers of radiation in medicine due to the data situation. Having said that, today we act on the assumption that damages like tumors may be more likely with higher doses of radiation we are exposed to in addition to our so-called background radiation. In Germany, the average annual dose of radiation we absorb via the air, food, and environment amounts to approximately two millisieverts. By comparison, a CT scan of the chest ranges between one and ten millisieverts. This is why we should keep doses of medical radiation as low as possible. This also applies to interventional radiology, which is studied here in Magdeburg as part of the Research Campus STIMULATE as it pertains to optimization options.

What are today's available options to regulate radiation?

Hoeschen: We are primarily able to regulate the quality of x-rays and how "hard" or "soft" they are, meaning how well they pass through the body. This can be achieved via voltage settings or by filtering x-ray photons. We can reduce the stray radiation dose in the body through an anti-scatter grid. And we can obviously also vary the number of x-ray photons, that being the dose of radiation. However, a lower dose also lets you see less, which is why we have to find the optimal balance between benefit and risk.

Generally speaking, medical imaging today essentially only uses digital systems, which enable us to also use edge enhancement or noise reduction to improve image quality. This allows us to see very different things, which can make a major difference in diagnostics.

Do manufacturers also contribute to optimize radiation dosage?

Hoeschen: For the past ten years, the importance of radiation protection has also increased for manufacturers. The radiation exposure from medical resources - at least in Germany – is still on average the biggest radiation exposure source. Having said that, a lot can be improved in this area in view of individualization of therapy and diagnostics, where existing technologies are optimally used and advanced.

When it comes to pediatric CT procedures, it would be especially beneficial to use very low doses of radiation, meaning soft radiation. There is still lots of work to be done in this area because we still have not achieved optimal settings in all situations from an equipment and application perspective. Europe is still a very long way away from being truly able to say that we are protecting all people as much as possible from ionizing radiation in medicine, while simultaneously fully unleashing the potential of ionizing radiation for diagnostic and therapeutic purposes.

What does optimal radiation protection in medicine look like in ten years if it were up to you?

Hoeschen: At least in Europe, we ideally would have a standard system with guidelines, which specify the diagnostic and therapeutic measures for specific issues.

We would collect all of the important patient parameters in an assistance system that makes recommendations based on these guidelines. The application is followed by a clinical evaluation of the diagnosis or treatment and documentation of the entire process. On the whole, all radiation protection measures that were defined as necessary and sensible would have to be applied, while patients would also be given a voice in the overall process.