S2474
Physics - Radiomics, functional and biological imaging, and outcome prediction
ESTRO 2026
Results: Figure1 shows the variation of standard deviation and interquartile range for both AD and RD in the three times. Following a brief initial increase for the KiL group, an overall decrease after 3 months is observed (-2.42%AD, -18.51%RD and -36.88%AD, -51.76%RD for standard deviation and interquartile range, respectively); the KiH, instead, shows an increasing trend during all the evaluation time (+75.58%AD, +71.72%RD and +163.95%AD, +160.72%RD for standard deviation and interquartile range, respectively).
derived parameters may serve as prognostic biomarkers reflecting tumour proliferation. Further analysis on a larger patient’s cohort is necessary to confirm these preliminary results. References: Duan, W. et al. (2022) “Single-cell transcriptome profiling reveals intra-tumoral heterogeneity in human chordomas”, https://doi.org/10.1007/s00262-022- 03152-1Andersson, J.L.R. et al. (2016), “An integrated approach to correction for off-resonance effects and subject movement in diffusion MR imaging”, https://doi.org/10.1016/j.neuroimage.2015.10.019. Keywords: Temporal analysis, Advanced Diffusion MRI Multi-institutional in-vivo characterization of consensus measurement methods for T1 and T2 mapping on the 1.5T Unity MR-linac Travis C. Salzillo 1 , Erik van der Bijl 2 , Ryan P.B. Bonate 3 , Ergys D. Subashi 1 , Warren Foltz 4 , Marijn Kruiskamp 5 , Eric Paulson 3 , Bjorn Stemkens 6 , Marielle E.P. Philippens 7 , Michael J. van Rijssel 7 1 Radiation Oncology, UT MD Anderson Cancer Center, Houston, USA. 2 Radiotherapy, RadboudUMC, Nijmegen, Netherlands. 3 Radiation Oncology, MCW, Milwaukee, USA. 4 Radiation Oncology, UHN, Toronto, Canada. 5 MR Therapy, Philips, Best, Netherlands. 6 MR/RT, Elekta, Best, Netherlands. 7 Radiotherapy, UMC Utrecht, Utrecht, Netherlands Purpose/Objective: Magnetic resonance relaxation time measurements (T1, T2) have long-standing consideration as imaging biomarkers for tumor characterization and treatment response and are promising for adaptive radiation therapy applications [1]. To facilitate consistent and high-quality longitudinal trials between institutions, a working group was established to develop consensus protocols across the global Unity MR-Linac community [2]. The 1.5T Unity MR-Linac has a unique quantitative potential, because each patient is re-imaged throughout the course of treatment and each installation shares identical MRI hardware and methodologies [3]. This group has already evaluated protocols for accuracy, repeatability, and Mini-Oral 3869 reproducibility using the Eurospin standardization phantom at participating institutions [4]. This abstract provides a preliminary summary of T1 and T2 data quality across multiple institutions in healthy volunteers. Material/Methods: Candidate protocols for T1 relaxation (DESPOT1 and MIRACLE [5,6] ) and T2 relaxation (MEMS TSE, DESPOT2, and MIRACLE [5–8] ) were acquired in 3 male volunteers at least twice on 4 separate Unity MR-
Figure 2 shows a qualitative example of advanced DWI maps.
Conclusion: This study evaluated the variation of DWI directional diffusion parameters on patients with SBC at different times, after CIRT treatment. The findings suggest that
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