A focused very high energy electron beam for fractionated stereotactic radiotherapy

• Published in: Scientific reports 2021-03, Vol.11 (1), p.5844-5844, Article 5844
• Main Authors: Svendsen, Kristoffer, Guénot, Diego, Svensson, Jonas Björklund, Petersson, Kristoffer, Persson, Anders, Lundh, Olle
• Format: Article
• Language: English
• Subjects: 639/166/985; 639/624/1020; 639/766/1960/1135; 639/766/25; 692/4028; Clinical Medicine; Dose Fractionation, Radiation; Electromagnetic Phenomena; Electrons; Energy; Humanities and Social Sciences; Klinisk medicin; Medical and Health Sciences; Medicin och hälsovetenskap; Mimicry; multidisciplinary; Particle Accelerators; Phantoms, Imaging; Radiation therapy; Radiologi och bildbehandling; Radiology, Nuclear Medicine and Medical Imaging; Radiometry; Radiosurgery; Science; Science (multidisciplinary); Slabs
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-85451-8

An electron beam of very high energy (50–250 MeV) can potentially produce a more favourable radiotherapy dose distribution compared to a state-of-the-art photon based radiotherapy technique. To produce an electron beam of sufficiently high energy to allow for a long penetration depth (several cm), very large accelerating structures are needed when using conventional radio-frequency technology, which may not be possible due to economical or spatial constraints. In this paper, we show transport and focusing of laser wakefield accelerated electron beams with a maximum energy of 160 MeV using electromagnetic quadrupole magnets in a point-to-point imaging configuration, yielding a spatial uncertainty of less than 0.1 mm, a total charge variation below 1 % and a focal spot of 2.3 × 2.6 mm 2 . The electron beam was focused to control the depth dose distribution and to improve the dose conformality inside a phantom of cast acrylic slabs and radiochromic film. The phantom was irradiated from 36 different angles to obtain a dose distribution mimicking a stereotactic radiotherapy treatment, with a peak fractional dose of 2.72 Gy and a total maximum dose of 65 Gy. This was achieved with realistic constraints, including 23 cm of propagation through air before any dose deposition in the phantom.