ESTRO 2024 - Abstract Book

S4989

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

Results:

14 patients were recruited into study. 11 patients had complete data sets i.e. 5 weekly scans. However, 3 patients had 2 or more scans missing due to scheduling difficulties or poor imaging quality. Only mean D factor in GTV between first (Mean D factor = 1.216 x 10-3 mm/s2) and last fraction (Mean D factor = 1.481 x 10-3 mm/s2) was found to be significant (p<0.001) demonstrating an increase following treatment, which can be interpreted as a response to treatment. An increasing trend in f is also seen within the GTV, but no significance is seen between first and last fraction (16.9% vs 22.5%; p=0.37). No trend is seen for D* in GTV. In comparison no trends are seen in any factor in normal rectal tissue, further reinforcing that changes seen within the GTV are likely due to response to treatment.

Conclusion:

This preliminary work on IVIM factors on MR-Linac, in particular the model parameters D and f, appears to detect biological change in cervical cancer which may be interpreted as a response to treatment. In comparison, no changes can be seen in normal rectal tissue which provides further support to treatment response changes may be detected within the GTV. Further work is required to stratify trends according to patient outcomes as there is heterogeneity amongst patients. Although population changes may not be significant, individual patient responses may be observable which could allow IVIM parameters on MR-Linac to be used as imaging biomarkers.