Stefanie Girst (Germany)
Universität der Bundeswehr München Institute for applied physics and measurement technologyAuthor Of 1 Presentation
STATUS AND PERSPECTIVES OF COMBINING PROTON MINIBEAM WITH FLASH RADIOTHERAPY
Abstract
Background and Aims
Proton minibeam radiotherapy (pMBRT) is an external beam radiotherapy method with reduced side effects by taking advantage of spatial fractionation in the normal tissue. Due to scattering, the delivered small beams widen in the tissue ensuring a homogeneous dose distribution in the tumor. In the last decade, several preclinical studies have been conducted addressing normal tissue sparing and tumor control in-vitro and in-vivo, using human skin tissue and mouse or rat models. In some of the studies due to application requirements the dose-rates are high such that additionally the FLASH effect comes into play. The aim is to investigate how the two effects of spatial and temporal focussing can interact and further widen the therapeutic window.
Methods
This study sumarizes the knowledge gathered in the experimental studies performed on pMBRT. Furthermore biological and physical effects of this therapy method are explained. Additionally, technical feasibility and limitations will be discussed by looking at simulations as well as preclinical studies.
Results
With pMBRT, higher radiation tolerance of tissue can be achieved resulting in the possibility of using higher doses per fraction. Some of the studies shown, already used FLASH dose rates and the results are all positive.
Conclusions
This opens the possibility of hypofractionation, reducing costs as well as physical and mental stress for the patient. Additionally, pMB FLASH radiotherapy seems to be an even more promising therapeutic approach. Finally, the technology for producing such beams is already existing, but must be adapted to the special requirements of minibeam fractionation, interlacing and FLASH pMBRT.