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Detectability and intra-fraction motion of individual elective lymph nodes in head and neck cancer patients on the Magnetic Resonance Image guided linear accelerator.
- Source :
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Physics and imaging in radiation oncology [Phys Imaging Radiat Oncol] 2024 Jan 04; Vol. 29, pp. 100532. Date of Electronic Publication: 2024 Jan 04 (Print Publication: 2024). - Publication Year :
- 2024
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Abstract
- Background and Purpose: Individual elective lymph node irradiation instead of elective neck irradiation is a new concept for head-and-neck cancer (HNC) patients developed for the Magnetic Resonance Image guided linear accelerator (MR-linac). To prepare this, the detectability, volume changes and intra-fraction motion of elective lymph nodes on the MR-linac was assessed.<br />Materials and Methods: A total of 15 HNC patients underwent diagnostic pre-treatment MRI. Additionally, two MR-linac scans were obtained with a 10-minute time difference in the first week of radiation treatment. Elective lymph node contours inside lymph node levels (Ib-V) were segmented on the pre-treatment MRI and the MR-linac scans and compared on number and maximal transversal diameter. Intra-fraction motion of elective lymph nodes on the MR-linac was estimated using Center of Mass (COM) distances and incremental isotropic expansion of lymph node segmentations.<br />Results: Of all 679 detected lymph nodes on the pre-treatment MRI, eight lymph nodes were not detectable on the first MR-linac scan and 16 new lymph nodes were detected. Lymph node diameters between the pre-treatment MRI scan and the MR-linac scan varied from -0.19 to + 0.13 mm. COM distances varied from 1.2 to 1.7 mm and lymph node contours had to be expanded with 3 mm.<br />Conclusions: Nearly all elective lymph nodes were detectable on the 1.5T MR-linac scan with no major changes in target volumes compared to the pre-treatment MRI. Simulated intra-fraction motion during the MR-linac scans was smaller than the 5-mm margin that will be used in the first elective lymph node radiation treatment.<br />Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (© 2024 Published by Elsevier B.V. on behalf of European Society of Radiotherapy & Oncology.)
Details
- Language :
- English
- ISSN :
- 2405-6316
- Volume :
- 29
- Database :
- MEDLINE
- Journal :
- Physics and imaging in radiation oncology
- Publication Type :
- Academic Journal
- Accession number :
- 38317852
- Full Text :
- https://doi.org/10.1016/j.phro.2024.100532