Presenter of 1 Presentation
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).
Author Of 1 Presentation
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).