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Matejcek, C.* ; Winter, J. ; Aulenbacher, K.* ; Dimroth, A.* ; Natour, G.* ; Bartzsch, S.

A novel electron source for a compact x-ray tube for microbeam radiotherapy with very high dose rates.

Phys. Med. 106:102532 (2023)
DOI PMC
Microbeam radiotherapy (MRT) is a novel concept in radiation oncology with arrays of alternating micrometer-wide high-dose peaks and low-dose valleys. Preclinical experiments have shown a lower normal tissue toxicity for MRT with similar tumor control rates compared to conventional radiotherapy. A promising candidate for the demanded compact radiation source is the line-focus x-ray tube. Here, we present the setup of a prototype for an electron accelerator being able to provide a suitable x-ray beam for the tube. Several beam dynamic calculations and simulations were performed concerning particle tracking, thermal and electrostatic properties of the electron source, resulting in a proper beamline, including the cathode, the pierce electrode (PE) and the focusing magnets. These parts are discussed separately. The simulations showed that a rectangular cathode with a small width of 0.4mm is mandatory. To quickly shut down the electron beam, an additional voltage of -600V must be applied to the PE. Moreover, the electric field inside the vacuum chamber stays below 10MVm-1 to minimize the risk of field emission. The thermal simulation validates a small displacement of 0.1mm of the heated cathode with respect to the PE, which must be considered during manufacturing of the cathode-PE assembly. The simulations lead to an adequate choice of cathode, electrodes and beamline to achieve the required focal spot of 0.05×20mm2 with a beam current of 0.3A and an electron energy of 300keV. With this setup first MRT experiments with high dose rates up to 10Gys-1 can be executed.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter Electron Source ; Electrostatic Simulation ; Line-focus X-ray Tube ; Microbeam Radiation Therapy ; Thermal Simulation ; Tracking Simulation; Radiation-therapy
ISSN (print) / ISBN 1120-1797
e-ISSN 1724-191X
Zeitschrift Physica Medica: European Journal of Medical Physics
Quellenangaben Band: 106, Heft: , Seiten: , Artikelnummer: 102532 Supplement: ,
Verlag Elsevier
Verlagsort The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, Oxon, England
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Institute of Radiation Medicine (IRM)
Helmholtz AI - FZJ (HAI - FZJ)
Förderungen German Research Foundation (Deutsche Forschungsgemeinschaft)