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MARTIN HJELLSTRÖM
Dissertation defense: 5 June 2024 (click for details)
Doctoral thesis:
Research area: Medical Radiation 91̽��s
Sahlgrenska Academy, The Institute of Clinical 91̽��s

What is the background of your thesis?
“After a radiological or nuclear (RN) event, such as the Chernobyl disaster in 1986, there’s a need for significant measuring capacity to identify individuals who are radioactively contaminated and require medical care. It’s also important to identify those who aren’t contaminated and don’t need to worry,” says Martin Hjellström, a medical physicist currently pursuing a doctorate at the Institute of Clinical 91̽��s.

He continues, “Currently, Sweden lacks the measuring capacity that may be necessary. The research project essentially aims to enhance the national capability to estimate internal contamination of radioactive materials after an RN event.”

Developed a measurement method

What research have you done to increase Sweden’s measuring capacity?
“We have investigated the potential use of gamma cameras for this purpose. Gamma cameras are available in nuclear medicine departments at hospitals across the country. There are nearly 80 such systems. Implementing these systems would be a valuable addition to Sweden’s measuring capacity. The system that has been dedicated to estimating internal contamination of radioactive materials so far is known as whole-body counters. There are approximately 15 such systems available.”

What are the key research findings, and what practical benefits can they provide?
“We have developed a measurement method to estimate internal contamination using the gamma camera. Twenty-two gamma cameras have been calibrated to estimate internal contamination of the radioactive material Cesium-137, which is common in RN events. We have derived calibration factors for different types of gamma cameras. We expect that not yet calibrated systems should be able to use these results to estimate internal contamination,” says Martin Hjellström, adding:

“In other words, Sweden’s ability to estimate internal contamination has been enhanced, and the hope is that the gamma camera will be implemented as an instrument in the Swedish preparedness.”

“Growing concern for RN events”

What aspects of your doctoral project have been enjoyable and challenging?
“It has been enjoyable that there has been significant interest from various professions in the project and its results. But the reason for the interest stems from something very unfortunate, as Russia’s occupation of nuclear power plants in Ukraine increased concerns about the possibility of an RN event. This, of course, was also challenging because it created pressure to produce results as quickly as possible in the current security situation.”

Text: Jakob Lundberg