Irradiation with protons instead of X-rays is an important addition in the treatment of tumors. In order to optimize proton therapy, further research is needed into its precise radiobiological effects. To this end, researchers at Erasmus MC and TU Delft have developed a unique set-up to observe what happens in cells during proton therapy. The collaboration between different universities and disciplines is a fine example of convergence.

Magnified
At the Holland Proton Therapy Center (HollandPTC), an independent outpatient center founded by Erasmus MC, LUMC and TU Delft, there is a particle accelerator that generates a proton beam. Radiation physicist Dr. Marta Rovituso of HollandPTC supports researchers like Heemskerk with the physics aspects of their research. “I take care of absolute dosimetry: delivering exactly the desired radiation dose at the exact location of the cells. Tim then looks at the biological effects of the radiation. What’s unique about this project is that a microscope was placed in the beam line to watch the effects in real time.”

Perfectly in place
Within Erasmus MC, the Optical Imaging Centre (OIC) is the core facility for everything related to microscopy. The OIC faced a special task due to the request from Heemskerk, Essers and Rovituso. “The proton beam comes out of the wall horizontally,” says OIC specialist Dr. Johan Slotman. “So we had to tilt the microscope 90 degrees. That sounds simple, but it’s not trivial.” The challenge for Slotman and his colleague Dr. Gert-Jan Kremers was to position the cell culture vertically. “The glass plate with the cell culture has to be constantly heated at 37 degrees, so that the cells stay alive. Between the glass and the lens of the microscope there is also a thin layer of oil. All of that has to stay perfectly in place.” Together with Ernst van der Wal, team leader at TU Delft’s Electrical and Mechanical Support Office (DEMO), the necessary components were developed.