Vacuum technology in tumor, proton & heavy ion therapy
June 23, 2020
Proton Therapy is a new technology for cancer treatment that became qualified in the 1990s. Irradiation of human tissue by X-ray photons destroys healthy tissue on its path to the tumor and behind. In the case of proton beams, the protons decelerate only slowly until they reach the point at which the beam is stopped. Tissue in the beam path absorbs only a very small dose relative to photon beams. At the end of the range, the protons are stopped at the 'Bragg Peak' (see image 2) and transfer a large amount of energy to the tumor - and almost zero behind. Therefore, proton therapy is a powerful but gentle tool where damage to healthy tissue is minimized. It can avoid many surgeries and can be used for complicated treatments such as tumors in eyes to avoid complete removal!
Heavy Ion Therapy challenges vacuum technology with Ultra High Vacuum requirements.
It is an enhancement of proton therapy and uses heavier ions like C+ instead of protons. Destruction of cancer cells is even more efficient. The technology applied in heavy ion therapy is more complex: The ions are generated in an ion source, accelerated in a linear accelerator and then fed into a synchrotron. In the synchrotron, ions are further accelerated and guided by magnets in circular tracks before guided into the beamlines. The synchrotrons have circumferences of up to 100 m. A pressure well below 1 x 10-09 mbar is required to ensure ions travel such long distances without interaction. This leads to UHV technology, using ion pumps, dry roughing systems and even a bakeable beam guiding system. Since it is common today to use superconducting magnets in the synchrotron, the cold walls support the pumping.
Setting up a proton therapy center demands an extraordinary investment and the heavy ion therapy even more so. But this is justified by the outstanding prospect of healing success.
In this blog we have outlined the importance of vacuum technology in different medical procedures as well as the role various vacuum pumps play in their performance.