# FLASH research accelerators (Oriatron, Mobetron FLASH, ProBeam FLASH)

Source: https://onco.cc/technologies/flash-research-accelerators/  
OnCo record `flash-research-accelerators` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Machines built or modified to deliver a whole radiation dose in a fraction of a second, so scientists can test whether ultra-fast dosing spares healthy tissue in people the way it does in animals.

## Summary

Ordinary linacs deliver a few gray a minute; FLASH needs dose rates of tens of gray a second, so it requires either a purpose-built electron accelerator, a proton system with its beam current and scanning re-engineered, or an intraoperative electron machine run in a special mode. The Oriatron eRT6, a 6 MeV electron linac built by PMB-Alcen for Lausanne University Hospital, gave the first human FLASH treatment in 2018 to a patient with a cutaneous lymphoma lesion. IntraOp's Mobetron mobile electron linac offers a FLASH mode for research, and PMB-Alcen's spin-off THERYQ is developing a dedicated FLASHKNiFE electron system and, with CERN and Lausanne, very high energy electron machines for deep tumours. Varian modified a ProBeam proton system for the FAST-01 trial at the Cincinnati Children's/UC Health proton centre, the first proton FLASH trial in people, treating painful bone metastases, followed by FAST-02.

These machines are research instruments: electron FLASH reaches only a few centimetres deep, proton FLASH so far uses transmission beams that pass through the patient rather than stopping in the tumour, dosimetry at these rates needs new detectors, and the sparing effect has yet to be shown in a randomised trial. If the biology holds, the payoff would be higher tumour doses with fewer side effects and treatment so fast that organ motion stops mattering.

## Fields

- Kind: Technology
- Status: phase-1
- Last checked: 2026-09-17
- Tags: machines-wave2
- Principle: High-current electron linacs or re-engineered proton systems deliver dose rates above roughly 40 gray a second so that an entire fraction is completed in milliseconds, the regime in which preclinical studies show normal-tissue sparing.
- Since: 2018
- Strengths: Tests a potentially large normal-tissue sparing effect; Delivery too fast for breathing motion to matter; Adaptable from existing electron and proton platforms
- Limitations: Electron beams reach only superficial targets; Dosimetry at ultra-high dose rate is unproven; No randomised evidence in patients yet

## Sources

- Bourhis et al., Treatment of a first patient with FLASH-radiotherapy (Radiotherapy and Oncology 2019): https://doi.org/10.1016/j.radonc.2019.06.019
- Mascia et al., Proton FLASH radiotherapy for the treatment of symptomatic bone metastases: the FAST-01 trial (JAMA Oncology 2023): https://doi.org/10.1001/jamaoncol.2022.5843

## Connected records

- technologies: [C-arm medical linear accelerators (TrueBeam, Versa HD and others)](https://onco.cc/technologies/c-arm-linac/), [Electron beam therapy systems (linac electrons, total skin electron units, mobile electron IORT)](https://onco.cc/technologies/electron-beam-therapy-systems/), [FLASH radiotherapy](https://onco.cc/technologies/flash-rt/), [In vivo dosimetry and patient-specific quality assurance](https://onco.cc/technologies/in-vivo-dosimetry/), [Proton therapy machines: cyclotrons, synchrotrons and single-room systems](https://onco.cc/technologies/proton-therapy-systems/), [Radiotherapy QA phantoms and dosimeters (Sun Nuclear, IBA Dosimetry, PTW)](https://onco.cc/technologies/radiotherapy-qa-phantoms-dosimeters/)
- cancers: [Cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)](https://onco.cc/cancers/cutaneous-t-cell-lymphoma/), [Head and neck squamous cell carcinoma](https://onco.cc/cancers/head-and-neck/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)
- terms: [Bone metastases and skeletal-related events](https://onco.cc/terms/bone-metastases/)
- fronts: [Devices & Physical Therapies](https://onco.cc/fronts/devices/), [Radiation Therapy](https://onco.cc/fronts/radiation/)
- companies: [IntraOp Medical](https://onco.cc/companies/intraop-medical/), [Varian (Siemens Healthineers)](https://onco.cc/companies/varian/)

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