Experimental Platform for Ultra-high Dose Rate FLASH Irradiation of Small Animals Using a Clinical Linear Accelerator.
A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC).



We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head.



Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume.



We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community.
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Emil
E
Schüler
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Stefania
S
Trovati
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Gregory
G
King
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Frederick
F
Lartey
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Marjan
M
Rafat
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
Manuel
M
Villegas
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
A Joe
AJ
Praxel
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California. Electronic address: BWLoo@stanford.edu.
Billy W
BW
Loo
Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California. Electronic address: PMaxim@stanford.edu.
Peter G
PG
Maxim
D000005:Abdomen / Q000000981:diagnostic imaging; D000818:Animals; D002138:Calibration; D004867:Equipment Design / Q000379:methods; D005373:Film Dosimetry / Q000379:methods; D009010:Monte Carlo Method; D058958:Organs at Risk / Q000528:radiation effects; D010315:Particle Accelerators / Q000295:instrumentation*; D011833:Radiation Injuries, Experimental / Q000517:prevention & control; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D011879:Radiotherapy Dosage; D013909:Thorax / Q000000981:diagnostic imaging