Proton therapy. Whereas conventional radiotherapy uses beams of photons or electrons, proton therapy consists of a beam of protons – elementary particles carrying a positive charge – obtained from an accelerator.
The advantage of protons is that they do not scatter much in the tissue. The beam is focused on the target cells without causing too much damage to the surrounding tissue.
The dose delivered to the tissue is maximized by the "Bragg's Peak" phenomenon, named after the physicist William Henry Bragg who discovered how a proton beam behaves.
The protons pass through matter to deposit almost all their energy at a given depth, and then come to a dead stop. They scatter very little along the path of the beam resulting in a beam with an almost cell-level precision.
Using these properties, by determining the initial energy of the protons, the depth and exact location to be reached in the tissue can be determined.
To do this, however, a 3D representation of the target area must be created from the scanned images. This model is used to guide the proton beam during the operation. However, there is no live return of the image of the actually destroyed cells.
Innovation. Based on the work on gamma rays carried out as part of the CMS experiment (named after the Compact Muon Solenoid Detector) at CERN, the founders of Terapet have developed a technology for analysing the trajectory of these gamma rays.
Two types of gamma rays are emitted when a proton beam interacts with cells. By intersecting the trajectories of these rays, the start-up found a way to represent in real-time and in three dimensions the exact location of the proton beam in a patient's body without even having to use a contrast medium.
According to company co-founder Christina Vallgren:
"We give eyes to doctors who use proton therapy."
Terapet is in the process of filing three patents on this technology.
What's next. The funds raised and the research programme with CERN financed by Innosuisse will enable the company to develop its first prototype on an industrial scale.
Such a device is essential for conducting clinical trials on patients to demonstrate the safety and effectiveness of the technology.
A booming market. More than 200,000 patients have been treated worldwide with protons.
The textbook case is the treatment of ocular melanoma. Proton therapy is the only method capable of treating this cancer while preserving sight. The Paul Scherrer Institute in Aargau, the only proton therapy centre in Switzerland, is a pioneer in this type of treatment.
The indications for proton therapy are rapidly expanding, particularly in paediatrics and even in the cardiovascular field with another CERN spin-off: EBAMed.