TY  - JOUR
AU  - Boeke, Simon
AU  - Habrich, Jonas
AU  - Kübler, Sarah
AU  - Boldt, Jessica
AU  - Schick, Fritz
AU  - Nikolaou, Konstantin
AU  - Kübler, Jens
AU  - Gani, Cihan
AU  - Niyazi, Maximilian
AU  - Zips, Daniel
AU  - Thorwarth, Daniela
TI  - Longitudinal assessment of diffusion-weighted imaging during magnetic resonance-guided radiotherapy in head and neck cancer.
JO  - Radiation oncology
VL  - 20
IS  - 1
SN  - 1748-717X
CY  - London
PB  - BioMed Central
M1  - DKFZ-2025-00255
SP  - 15
PY  - 2025
AB  - For radiotherapy of head and neck cancer (HNC) magnetic resonance imaging (MRI) plays a pivotal role due to its high soft tissue contrast. Moreover, it offers the potential to acquire functional information through diffusion weighted imaging (DWI) with the potential to personalize treatment. The aim of this study was to acquire repetitive DWI during the course of online adaptive radiotherapy on an 1.5 T MR-linear accelerator (MR-Linac) for HNC patients and to investigate temporal changes of apparent diffusion coefficient (ADC) values of the tumor and subvolume levels.27 patients treated with curative RT on the 1.5 T MR-Linac with at least weekly DWI in treatment position were included into this prospective analysis and divided in four risk groups (HPV-status and localisation). Tumor and lymph node volumes (GTV-P/GTV-N) were delineated on b = 500 s/mm2 images while ADC maps were calculated using b = 150/200 and 500 s/mm2 images. Absolute and relative temporal changes of mean ADC values, tumor volumes and a high-risk subvolume (HRS) defined by low ADC tumor voxels (600 < ADC < 900 × 10-6 mm2/s) were analyzed. Relative changes of mean ADC values, tumor volumes and HRS were statistically tested using Wilcoxon-signed-rank test.Median pretreatment ADC value for all patients resulted in 1167 × 10-6 mm2/s for GTV-P and 1002 × 10-6 mm2/s for GTV-N while absolute pretreatment tumor volume yielded 9.1 cm3 for GTV-P and 6.0 cm3 for GTV-N, respectively. Pretreatment HRS volumes were 1.5 cm3 for GTV-P and 1.3 cm3 for GTV-P and GTV-N. Median ADC values increase during 35 fractions of RT was 49
KW  - Apparent diffusion coefficient (Other)
KW  - Head and neck cancer (Other)
KW  - MR-guided radiotherapy (Other)
KW  - Quantitative magnetic resonance imaging (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:39881423
DO  - DOI:10.1186/s13014-025-02589-9
UR  - https://inrepo02.dkfz.de/record/298354
ER  -