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CERN | CLEAR study paves the way for novel electron-based cancer therapy

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High-energy electron beams can be focused onto deep-seated cancerous tumours


The study, conducted at CERN’s CLEAR test facility, demonstrates how very high-energy electron beams can be focused onto deep-seated cancerous tumours.

There are some cancer tumours that not even surgery, chemotherapy or traditional radiation therapy can cure. These resistant tumours contribute to making the disease one of the main causes of mortality worldwide, but the scientific community is teeming with ideas to make cancer fatalities a thing of the past. Among the latest medical and technological innovations, progress in particle therapy – the process of irradiating tumours using highly energetic particle beams generated by a particle accelerator – allows the treatment of tumours that would otherwise have been fatal.

More than 10 000 small electron linear accelerators (linacs) are currently used for cancer treatment worldwide. Most of these machines rely on photon beams generated by electrons to irradiate their target. Some, however, use the electron beam itself for direct low-energy electron irradiation, although this can only reach superficial tumours. These methods differ from hadron therapya technique based on irradiation with protons or heavy ion beams.

A possible complement to hadron and low-energy electron therapy is the use of high-energy electron beams within the 50-200 MeV range, which can penetrate deep into tissues. However, this technique is rarely used due to the higher cost and larger size of the accelerator needed to produce them compared to photon facilities. In addition, their depth profile is less well defined than that achieved with hadron beams. Recent developments in high-gradient acceleration for compact linear accelerators, mainly driven by the CLIC study at CERN, have started to change the story.

A recent finding might constitute a further step towards the use of high-energy electron beams. Two studies involving the universities of Strathclyde and Manchester were carried out at CERN’s linear electron accelerator for research (CLEAR), a test facility that serves research and development efforts on accelerator technology. Researchers tested a new irradiation technique involving very high-energy electron (VHEE) beams focused on a small, dense spot.


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