Rosana Turtos

Project title

Dose-i-colors: Solid-state nanodosimetry based on color centers operating at room temperature

What is your project about?

The project is about discovering a new way of measuring tiny amounts of energy deposited in matter when an atom or DNA molecules are broken by the interaction with ionizing radiation. Currently, these minute energy depositions, resulting from single or multiple ionization events, are the fundamental mechanisms responsible for radiation-induced damage, and this is key for killing cancer tumours in an important technique called radiotherapy. However up to now, physicist can only access what happens at the DNA scale when measuring far from living-human conditions and current techniques can only quantify the amount of damage within a single localized region for a single ionizing particle without any spatial information. The project will investigate the physical mechanisms and invent a new technique enabling scientists to directly image the fundamental interactions of ionizing radiation at the nanoscale in experimental conditions relevant to radiotherapy.

How did you become interested in your particular field of research?

Throughout my career, I have been fascinated by nature’s exquisite mechanisms that allow us to observe – and therefore measure – previously inaccessible forms of energy. Here, photons are particularly powerful carriers of information because they are massless and electrically neutral. During my PhD and fellowship at CERN, I studied how crystals can promptly generate photons, with applications in real-time cancer imaging. After moving to Aarhus, I investigated a complementary mechanism that stores part of the deposited energy and releases it as light on demand. This work enabled the first reusable material capable of verifying radiotherapy treatment plans in all three dimensions.  

The connection between precise measurements, imaging, and cancer treatment has shaped my career, which has been surrounded by fantastic colleagues, students and mentors. I now aim to explore a new luminescence mechanism that could reveal how ionizing radiation damages matter at the nanoscale.

What are the scientific challenges and perspectives in your project?

A main scientific challenge would be to prepare matter with a given number of atomic defects, so that ionizing radiation can generate specific constellations of complex defects, called colour centers, emitting light of different colours. This would allow us to play with the sensitivity of radiation-induced processes and obtain for the first time an ionization map that tells about the very beginning of radiation damage. In the lab, this will materialize in creating atomic defects in a crystal with a powerful laser and moving atoms from one place to another. We have recently sucedeed in doing this manipulation, as if we were ‘painting’ crystals and we are very excited about it. Such manipulation opens many possibilities for playing with matter and probing physics at the atomic scale.    

Now the scientific challenge lies in harnessing these new possibilities in a material that has the right electronic density but it is difficult to excite in a controlled way due to its electronic structure.

What is your estimate of the impact, which your project may have to society in the long term?

Measuring and making these ionization maps in conditions relevant for the clinic is essential for understanding complex damage and repair mechanisms at the cellular and systemic level, where the biology of living organisms takes over the physics.  The idea is to provide the community with a technique that would allow us to track how radiation damage evolve from its very origin, i.e. few attoseconds or femtosecond after the initial interaction up to many months after. This is key for designing the cancer treatments of the future where radiotherapy can be increasingly inspired by the living human.  

From the point of view of particle physics, the project would provide insight into new ways of sensing and radiation damage mechanims in inorganic matter, which are key for building radiation-hard detectors for future particle accelerators.

Which impact do you expect the Sapere Aude programme will have on your career as a researcher?

The Sapere Aude grant is an important step in my career, as it will allow me to consolidate both my research group and my laboratory, Exciton Lab. In addition, the program will enable me to hold an associate professorship for four years and bring me one step closer to my dream of building a successful academic career.  

The project will also strengthen the collaboration between partners at the Danish Center for Particle Therapy in Aarhus and CERN, where the Exciton group is part of a new collaboration on quantum sensors for particle physics.   As a female researcher, the grant also gives me the opportunity to influence and inspire a diverse group of people. I currently lead the Exciton group, which has a 50/50 gender distribution, and I am also part of a larger research group where women are strongly represented. Together with my talented colleagues at the Physics department, I want to continue the work of promoting both diversity and research excellence.