Presenter 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.
Author Of 3 Presentations
NEW R&D PLATFORM WITH UNIQUE CAPABILITIES FOR ELECTRON FLASH AND VHEE RADIATION THERAPY AND RADIATION BIOLOGY UNDER PREPARATION AT PITZ
Abstract
Background and Aims
At the Photo Injector Test facility at DESY in Zeuthen (PITZ, near Berlin, Germany), the realization of an R&D platform for electron FLASH radiation therapy, VHEE radiation therapy and radiation biology is under preparation. The name of the new platform is HP²eFLASH-RT@PITZ, which stands for high power, high performance electron FLASH radiation therapy at PITZ.
Methods
The beam parameters that PITZ can provide are unique in the world: ps scale electron bunches with up to 5nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms in length.
Results
The individual bunches can produce dose rates up to 1014 Gy/s and dose deposition up to 1000 Gy. Upon demand, each bunch of the bunch train can be guided to a different transverse location on the tumor, so that either a “painting” with micro beams, or a cumulative increase of absorbed dose using a wide beam distribution can be realized at the tumor. Full tumor treatment can hence be finished in a time interval of 1 ms, mitigating organ movement issues. Together with 20 years of operational experience at PITZ, and availability of detailed beam characterization and extremely flexible beam manipulation capabilities, this R&D platform will cover current parameter range of successfully demonstrated FLASH effects and extend the parameter range towards yet unexplored and unexploited short treatment times and high dose rates.
Conclusions
A summary of the plans for HP²eFLASH-RT@PITZ and the status of the preparations will be presented, with as goal to stimulate interest and broaden out our cooperation.
PROTON-FLASH – RADIATION EFFECTS OF ULTRAHIGH DOSE-RATE IRRADIATION
Abstract
Background and Aims
The application of radiation with ultra-high dose-rates in radiotherapy shows a sparing effect on healthy tissue compared to cancerous tissue. This so-called FLASH-effect is mainly studied by using electrons or x-rays. Radiotherapy using protons already shows benefits in the low dose-rate application compared to conventional treatment. Therefore, a combination of both the particle-based sparing and the FLASH-effect could further widen the therapeutic window. Here, we investigated the FLASH-effect in proton treatment using an in-vivo mouse ear model.
Methods
For the experiment the right ears of 63 Balb/c mice were irradiated with 20 MeV protons at the ion microprobe SNAKE at the 14 MV tandem accelerator in Garching near Munich by using three dose-rates (3.7 Gy/min, 558 Gy/min, and 55,800 Gy/min). Additionally, we compared the FLASH-effect at 23 Gy and 33 Gy. For quantification, we measured the ear thickness, desquamation, and erythema for 180 days.
Results
No difference in the 23 Gy group for the different dose-rates was visible, whereas for the 33 Gy group it was significant. For 558 Gy/min we received a 57 % reduction of ear swelling and a 40 % reduction for 55,800 Gy/min compared to the conventional dose-rate of 3.7 Gy/min. Desquamation and erythema were reduced by 68 % and 50 %.
Conclusions
By using FLASH-dose-rates for low LET proton irradiation a tissue-sparing effect can be achieved. This effect seems to be more significant with increased dose and was also observed at a dose-rate four times smaller than usually used FLASH-dose-rates (≥ 2400 Gy/min).
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.