Does ¹⁸F-sodium fluoride PET/CT have a role in the assessment of response to ²²³Ra therapy in men with prostatic bone metastases?

Authors

Glen M Blake, Ricardo Donners, Amelia E B Moore, Holly Tovey, Aude Espinasse, Matthew D Blackledge, Sue Chua, Yong Du, Emma Hall, Dow-Mu Koh, Emilia Nuzzaci, Nina Tunariu, Christopher C Parker, Gary J R Cook

Published in

European journal of nuclear medicine and molecular imaging. Jun 20, 2026. Epub Jun 20, 2026.

Abstract

The REASURE study investigated imaging biomarkers in men receiving ²²³Ra treatment for prostate cancer bone metastases. We used REASURE data to compare and contrast the roles of [¹⁸F]NaF PET/CT measurements of maximum standardised uptake value (SUVmax) and bone metabolic flux (Ki) as markers of response.
Thirty-four men with prostatic bone metastases received up to six cycles of ²²³Ra (55 or 88 kBq/kg) at four-weekly intervals. Whole-body diffusion-weighted MRI and [¹⁸F]NaF PET/CT images were acquired at baseline and 4, 12, and 24 weeks later. Values of the apparent diffusion coefficient (ADC, a measure of tumour response), SUVmax, and a novel surrogate measurement of Ki using a PET/CT SUV measurement in the left ventricle were monitored in up to 5 bone metastases in each participant. Multilinear regression analysis (MLR) was performed to determine if changes in ADC were predicted by changes in SUVmax or Ki. Radium dose and baseline SUVmax were additional independent variables.
ADC values increased throughout the study, while SUVmax and Ki decreased. MLR analysis showed that baseline SUVmax and ²²³Ra dose predicted ADC response (P < 0.001 and P < 0.01, respectively). Changes in SUVmax and Ki at 4, 12, and 24 weeks failed to predict the changes in ADC, showing decoupling between MRI and PET/CT measurements as markers of response. Changes in Ki were a highly significant predictor of changes in SUVmax (P < 0.001), reflecting the strong correlation between these two measurements.
Baseline SUVmax was the best predictor of ADC response, followed by ²²³Ra dose. Changes in SUVmax and Ki failed to predict changes in ADC, suggesting that the changes in the PET/CT variables reflected the effect of ²²³Ra uptake on osteoblasts rather than a tumoricidal effect. A decrease in SUVmax seen on post-therapy [¹⁸F]NaF PET/CT scans should not be interpreted as evidence of tumour regression.
ISRCTN ISRCTN17805587. Registered 21/01/15.

PMID:
42321542
Bibliographic data and abstract were imported from PubMed on 20 Jun 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.