Ultra-high dose rate radiation production and delivery systems intended for FLASH
Higher dose rates, a trend for radiotherapy machines, can be beneficial in shortening treatment times for radiosurgery and mitigating the effects of motion. Recently, even higher doses (e.g., 100 times greater) have become targeted because of their potential to generate the FLASH effect (FE).
In a recent article published in Medical Physics, former OMA Fellow Sud Srinivasan and colleagues explore the production and delivery systems of ultra-high dose rate radiation (UHDR) for FLASH.
Comparison of PBS transmission (proton cyclotron) vs conformal (proton linac) 21 Gy single fraction UHDR plans for a 2 cm diameter brain and lung target (produced with RayStation, RaySearch AB, Stockholm).
The complete relationship between UHDR and the FE is unknown, but UHDR systems are needed to explore the relationship further and to deliver clinical UHDR treatments where indicated. Despite the challenging set of unknowns, the authors seek to make reasonable assumptions to probe how existing and developing technology can address the UHDR conditions needed to provide beam generation capable of producing the FE in preclinical and clinical applications.
As a preface, the paper discusses the known and unknown relationships between UHDR and the FE. Based on these, different accelerator and ionizing radiation types are then discussed regarding the relevant UHDR needs. The details of UHDR beam production are discussed for existing and potential future systems such as linacs, cyclotrons, synchrotrons, synchrocyclotrons, and laser accelerators. In addition, various UHDR delivery mechanisms are discussed, along with required developments in beam diagnostics and dose control systems.
Full article:
Farr, Jonathan; Grilj, Veljko; Malka, Victor; Sudharsan, Srinivasan; Schippers, Marco, “Ultra-high dose rate radiation production and delivery systems intended for FLASH”, MEDICAL PHYSICS 49(7), 4875 – 4911 (2022) https://doi.org/10.1002/mp.15659