A mask-compatible, radiolucent, 8-channel head and neck receive array for MRI-guided radiotherapy treatments and pre-treatment simulation.

Autor:	Zijlema SE; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.; Computational Imaging Group for MR Diagnostics & Therapy, Center for Image Sciences, University Medical Center Utrecht, The Netherlands., Breimer W; Tesla Dynamic Coils, Zaltbommel, The Netherlands., Gosselink MWJM; Department of Radiology, Division of Imaging & Oncology, University Medical Center Utrecht, The Netherlands., Bruijnen T; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.; Computational Imaging Group for MR Diagnostics & Therapy, Center for Image Sciences, University Medical Center Utrecht, The Netherlands., Arteaga de Castro CS; Tesla Dynamic Coils, Zaltbommel, The Netherlands., Tijssen RHN; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.; Department of Radiation Oncology, Catharina Hospital, Eindhoven, The Netherlands., Lagendijk JJW; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands., Philippens MEP; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands., van den Berg CAT; Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.; Computational Imaging Group for MR Diagnostics & Therapy, Center for Image Sciences, University Medical Center Utrecht, The Netherlands.
Jazyk:	angličtina
Zdroj:	Physics in medicine and biology [Phys Med Biol] 2022 Jun 24; Vol. 67 (13). Date of Electronic Publication: 2022 Jun 24.
DOI:	10.1088/1361-6560/ac6ebd
Abstrakt:	Immobilization masks are used to prevent patient movement during head and neck (H&N) radiotherapy. Motion restriction is beneficial both during treatment, as well as in the pre-treatment simulation phase, where magnetic resonance imaging (MRI) is often used for target definition. However, the shape and size of the immobilization masks hinder the use of regular, close-fitting MRI receive arrays. In this work, we developed a mask-compatible 8-channel H&N array that consists of a single-channel baseplate, on which the mask can be secured, and a flexible 7-channel anterior element that follows the shape of the mask. The latter uses high impedance coils to achieve its flexibility and radiolucency. A fully-functional prototype was manufactured, its radiolucency was characterized, and the gain in imaging performance with respect to current clinical setups was quantified. Dosimetry measurements showed an overall dose change of -0.3%. Small, local deviations were up to -2.7% but had no clinically significant impact on a full treatment plan, as gamma pass rates (3%/3 mm) only slightly reduced from 97.9% to 97.6% (clinical acceptance criterion: ≥95%). The proposed H&N array improved the imaging performance with respect to three clinical setups. The H&N array more than doubled (+123%) and tripled (+246%) the signal-to-noise ratio with respect to the clinical MRI-simulation and MR-linac setups, respectively. G -factors were also lower with the proposed H&N array. The improved imaging performance resulted in a clearly visible signal-to-noise ratio improvement of clinically used TSE and DWI acquisitions. In conclusion, the 8-channel H&N array improves the imaging performance of MRI-simulation and MR-linac acquisitions, while dosimetry suggests that no clinically significant dose changes are induced. (© 2022 Institute of Physics and Engineering in Medicine.)
Databáze:	MEDLINE
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