FLASH Irradiations

Flash at RARAF

RARAF offers FLASH irradiations in two modalities: 1) a decomissioned Varian Clinac accelerator system for electrons and 2) our Track-Segment and Horizontal Irradiation platform for protons. Both systems are available for users.

Electron FLASH with the Varian Clinac

The Varian Clinac accelerator system was decomissioned from patient thearpy at the Weill-Cornell Medical Center and relocated to RARAF. This systme is designed to propvice electon beams at set energies onto a coppor target to generate x-ray beams that are modulated and shaped to irradiate cancer in patients. There is also a mode that the copper target can be removed and the electron beam used directly in irradiation. We have modified the system to generate the electron beam at the intensistes typically used in the x-ray mode through the electron mode providing the dose rate needed for FLASH irradiation.

The Varian Clinac FLASH system has been used to look at cell cultures, ex-vivo blood samples, small animals, and novel detector systems for FLASH control. A publication describing the Varian Clinac FLASH system by Garty, et.al. is avaiable.

The modified Varian Clinac accelerator system at RARAF.

Staging area of the modified Varian Clinac for Conventional and FLASH irradiation modes.

Staging for small animals at the Varian Clinac

Mounting and staging solutions for different sample types at the Varian Clinac for FLASH irradiation.

Varian Clinac staging for different sample types.

Depth Dose measurements for different electron energies at the Varian Clinac.

Depth Dose measurement for different electron energies in FLASH.

Dicentric example from FLASH irradiation. Control on the Left and irradiated sample on the Right with dicentrics at arrows.

Chart demonstrating the difference in dicentric yield at 3 and 8 Gy looking at dose delivery time from Conventional dose rates to FLASH dose rates.

Dicentric yield in Conventional and FLASH modes

Proton FLASH

Proton FLASH at RARAF has been performed on the Track-Segment irradiation platform and our Horizontal beam line. The Track-Segment FLASH irradiation is a normal operation with a significantly higher dose rate and dish speed. The Horizontal FLASH system is a unique beam line at RARAF depicted below.

The Proton FLASH systems are limited to our maximum proton range in biological samples of ~0.5 mm making this system ideal for for cell culture experiments looking at end of range for therapy proton irradiators.

We have a pair of publications about this system by Grilj and Buonanno.