PORTFOLIO

Radiation therapy (RT) is one of the main therapies for cancer treatment. An overall cancer cure rate of approximately 50% is presently achievable. From those, 50% of curable cases need RT as part of the treatment regimen. The exact amount of radiation and the correct spatial distribution of radiation dose in a cancer patient are absolutely crucial for a successful therapy and represent a strong focus in mod-ern medical physics. Unfortunately, current systems used to measure those quantities (electronic de-tector arrays or film detectors) are inaccurate (low spatial resolution, low dose sensitivity, low dose dis-tribution resolution), present properties which depend on irradiation energy, and/or require complex steps of correction/development during use.
The aim of our project is to develop a simple, yet highly accurate film dosimetry detector system to be used during RT. Our approach will rely on recent advances in microfluidics and smart, optically-respon-sive polymers to develop films with high sensitivity and improved signal quality. A high-speed coating technique (spin coating) will be used to guarantee production of highly homogeneous thin films. Moreover, the recent developments in medical physics will be used to design an innovative analysis and data processing methodology for RT. The Radiopol project is a collaboration among material sci-entists of Empa and a medical physicist of KSSG. The successful completion of this project will have significant impacts for the whole society in terms of improved treatment of cancer patients, reduction of cancer-related healthcare costs, and promotion of the economic landscape of Switzerland.

Our originality lies in the application of concepts that are new in the field of radiation sensitive poly-mers, including the use of 2 techniques that are at the forefront of Mater. Sci., namely, microfluidic wet spinning processing and optically responsive polymers. Our innovation should be implemented in the market for ionizing radiation dosimetry, overcoming the weak link between the sole provider of radiochromic films with the medical physics community. It is a technological development, which will lead to the creation of a knowledge-intensive start-up. Ultimately, our films should bring benefit to society, the healthcare system, and the economy of Switzerland. We will promote a more personalized, safe, precise and cost effective use of ionizing radiation.

In the first half of Radiopol, we concentrated our efforts on investigating in detail the coating tech-nique in order to obtain films with the desired morphology as well as response to ionizing radiation. We identified the parameters who influence the optical properties of the films. We managed to in-crease the sensitivity of the film and understand how to steer the process. We also synthesized alterna-tive molecules that may have enhanced sensitivity when compared to the state-of-the-art.
In the second half, we then used the obtained deeper understanding to improve and optimize the fab-rication process, focusing on obtaining films with good responsiveness to radiation, reproducibility, smoothness, homogeneity over large areas, and transparency. We obtained laminated films whose sensitivity to 5Gy radiation could grant their use in radiochromic films, since they perform approxi-mately same as the commerical film used as high dose benchmark (EBT XD) and could be produced in large areas (100cm2). Further research will be dedicated on improving even further the responsiveness and homogeneity of the novel radiochromic films.