S2705
RTT - Patient preparation, immobilisation, and verification protocols
ESTRO 2026
demonstrate the impact when using no NMOC and yerba mate on duodenal conspicuity (blue arrows), respectively, in the same participant.T1-weighted imaging: Yerba mate increased duodenal conspicuity versus control (median Δ =+1 [IQR 0.25], r=0.90, p=0.023). Water produced a gain in pancreatic conspicuity (median Δ =+0.5, r=0.91, p=0.046) versus control.T2-weighted imaging: Baseline conspicuity was high; no consistent NMOC benefit was observed.Artefacts: No NMOC-related increase in artefacts; medians remained 3 – 4 (T1w) and 4 (T2w).Acceptability: 87% of responses reflected a positive sentiment across the palatability of all NMOCs (Likert 3 – 4), indicating overall acceptability. Nausea was not reported. Water rated best for texture. Yerba mate’s smell was least preferred but remained generally acceptable. No adverse events occurred.
Digital Poster 1153 Non-medicinal oral contrast to enhance gastrointestinal conspicuity for MR-guided liver SABR planning: a proof-of-concept healthy volunteer study. Matthew R Beasley 1 , Janine Bestall 2 , Vivian P Cosgrove 3 , Ann M Henry 4,5 , Louise J Murray 4,5 , Carole Burnett 6,7 1 Radiotherapy, Leeds Cancer Centre, Leeds, United Kingdom. 2 Leeds Institute of Health Sciences, University of Leeds, Leeds, United Kingdom. 3 Medical Physics & Engineering, Leeds Cancer Centre, Leeds, United Kingdom. 4 Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom. 5 Department of Clinical Oncology, Leeds Cancer Centre, Leeds, United Kingdom. 6 NIHR Leeds BRC, NIHR Leeds BRC, Leeds, United Kingdom. 7 Research and Innovation, Leeds Cancer Centre, Leeds, United Kingdom Purpose/Objective: To evaluate inexpensive non-medicinal oral contrasts (NMOCs) as a means to improve visibility of upper- abdominal structures on MRI sequences relevant to liver SABR planning, and to assess participant acceptability. Material/Methods: A single-centre, within-subject study including eight healthy volunteers was conducted (ethical approval: HRA 23/WM/0070). Each volunteer completed four MRI exams in a random order with i) no NMOC, ii) water, iii) pineapple juice and iv) yerba mate. A volume of 200mL of each NMOC was ingested 20 minutes before scanning; IV hyoscine butylbromide (Buscopan) was administered immediately before imaging. A 1.5T scanner was used to acquire axial T1-weighted breath- hold gradient echo (dual-echo in/out of phase) and axial T2-weighted respiratory-gated turbo spin echo. Two blinded radiographers (diagnostic and therapeutic) scored conspicuity of liver, stomach, duodenum, pancreas, and bowel, artefact severity and overall image quality on a 4-point Likert scale, including 1=impossible to use, 2=poor quality, 3=satisfactory, 4=excellent. Paired Wilcoxon tests compared each NMOC with control (no NMOC; α =0.10; effect size, r). A participant acceptability questionnaire captured sentiment of nausea, taste, texture, smell, and adequacy of prior information on a 4-point Likert scale including: 1=strongly disagree, 2=disagree, 3=agree, 4=strongly agree. Results: All volunteers completed all scans, yielding 64 evaluable images. Overall image quality was at least satisfactory in 62/64 scans (96.9%). Figures 1 and 2
Conclusion: Yerba mate demonstrated a T1-weighted
improvement in duodenal conspicuity. Water may aid pancreatic conspicuity on T1-weighted imaging. Given the small sample and multiple testing, these findings are hypothesis-generating. A liver SABR patient study to evaluate the effect of NMOCs on clinically relevant outcomes, including inter-observer contour agreement and any dosimetric impact, should follow. Keywords: MR-guided SABR, oral contrast, image quality
Poster Discussion
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