{"entity":{"id":"vhee-radiotherapy","kind":"technology","name":"Very-high-energy electron therapy","aka":[],"tldr":"VHEE radiotherapy fires electrons at 100 to 250 MeV, energies that reach deep tumours and can be steered by magnets, aiming to deliver FLASH-speed radiation from a machine smaller and cheaper than a proton facility. It is still at the accelerator-development and preclinical stage: no patient had been treated by September 2026.","summary":"Electrons in the 100-250 MeV range penetrate deeply, are steerable by magnets, and can be delivered at the ultra-high dose rates associated with the FLASH effect, in principle for a fraction of the cost of a proton facility. Work is at the accelerator-development and preclinical stage at CHUV/CERN, SLAC and elsewhere; the FLASH studies that exist in humans use conventional-energy electrons for skin lesions (for example NCT06549439, completed) or protons. No VHEE patient treatment had been reported by September 2026.","status":"preclinical","asOf":"2026-09-08","links":[{"label":"eFLASH skin melanoma study (NCT06549439)","url":"https://clinicaltrials.gov/study/NCT06549439"}],"tags":["frontier","radical"],"related":[],"cancers":[],"sections":["radiation"],"technologies":["flash-rt","proton-therapy","carbon-ion","imrt-igrt"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Very-high-energy electrons deposit a relatively flat depth dose that can be shaped magnetically, enabling deep targets and millisecond delivery.","strengths":["Potential FLASH sparing at depth","Magnetic scanning is fast and precise","Cheaper and smaller than proton or carbon facilities"],"limitations":["No clinical machine yet","Dosimetry at ultra-high dose rate is unsolved","FLASH sparing itself remains unproven in humans"]},"route":"/technologies/vhee-radiotherapy/","neighbours":{"section":[{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"technology":[{"id":"carbon-ion","kind":"technology","name":"Carbon-ion therapy","route":"/technologies/carbon-ion/"},{"id":"flash-rt","kind":"technology","name":"FLASH radiotherapy","route":"/technologies/flash-rt/"},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"proton-therapy","kind":"technology","name":"Proton therapy","route":"/technologies/proton-therapy/"}],"roadmap":[{"id":"frontier-2035","kind":"roadmap","name":"Radical oncology: what could change the war by 2035","route":"/roadmaps/frontier-2035/"},{"id":"radiation-roadmap","kind":"roadmap","name":"Radiotherapy roadmap: X-rays → shaped beams → fewer fractions, particles and FLASH","route":"/roadmaps/radiation-roadmap/"}]}}