Unlike in other radiotherapy methods, in hadron therapy the protons and ions deposit most of their energy at the very end of their path. This makes it possible to target a well-defined cancerous region deep in the body. This precise focus can be tuned by adjusting the energy of the incident particle beam, with reduced damage to the surrounding healthy tissues. Selective tumour irradiation requires state-of-the-art medical imaging techniques, both prior to and during treatment. Real-time imaging is needed to provide fast feedback while the dose is being delivered. The ENVISION (European novel imaging systems for ion therapy) project developed cutting-edge imaging solutions for hadron therapy. It aimed at improving safety, outcome and lowering the cost of this highly advanced radiation therapy. A consortium of 16 European research centres and 1 industrial partner addressed the problems of online dose monitoring. Project members developed novel imaging modalities related to dose deposition and derived reliable indicators of the delivered dose. The real-time observation became feasible by detecting the characteristic secondary emissions of the proton beams interacting with the tissue. ENVISION also made considerable progress in refining existing techniques, such as in-beam positron emission tomography. The consortium also brought innovative technologies (in-beam single photon tomography) closer to clinical deployment, and performed proof-of-principle testing of new in-beam single-charged-particle tomography. The project developed and built a full-size prototype of a knife-edge slit prompt gamma camera, which is currently being evaluated with clinical partners. Upon successful evaluation, this camera will provide an effective solution to improve the quality of treatments. Scientists also developed and compared methods for automated evaluation of the treatment results, optimised detector design and advanced imaging protocols. Imaging tools designed by the ENVISION consortium offer the possibility of tumour removal with unparalleled accuracy. This, in turn, could promote hadron therapy as a safe and efficient anticancer therapy of the future.
Imaging, anticancer, hadron therapy, tumour cells, real-time imaging, ion therapy