DOI: 10.1007/s00259-017-3744-yPages: 1832-1844

The potential of 223Ra and 18F-fluoride imaging to predict bone lesion response to treatment with 223Ra-dichloride in castration-resistant prostate cancer

1. Royal Marsden NHS Foundation Trust, Joint Department of Physics

2. The Institute of Cancer Research

3. Skåne University Hospital, Department of Radiation Physics

4. Royal Marsden NHS Foundation Trust, Department of Urology

5. Royal Marsden NHS Foundation Trust, Department of Nuclear Medicine

Correspondence to:
Iain Murray
Tel: +44(0)2086613715
Email: iain.murray@icr.ac.uk

Close

Abstract

Purpose

The aims of this study were to calculate bone lesion absorbed doses resulting from a weight-based administration of 223Ra-dichloride, to assess the relationship between those doses and corresponding 18F-fluoride uptake and to assess the potential of quantitative 18F-fluoride imaging to predict response to treatment.

Methods

Five patients received two intravenous injections of 223Ra-dichloride, 6 weeks apart, at 110 kBq/kg whole-body weight. The biodistribution of 223Ra in metastatic lesions as a function of time after administration as well as associated lesion dosimetry were determined from serial 223Ra scans. PET/CT imaging using 18F-fluoride was performed prior to the first treatment (baseline), and at week 6 immediately before the second treatment and at week 12 after baseline.

Results

Absorbed doses to metastatic bone lesions ranged from 0.6 Gy to 44.1 Gy. For individual patients, there was an average factor difference of 5.3 (range 2.5–11.0) between the maximum and minimum lesion dose. A relationship between lesion-absorbed doses and serial changes in 18F-fluoride uptake was demonstrated (r2 = 0.52). A log-linear relationship was demonstrated (r2 = 0.77) between baseline measurements of 18F-fluoride uptake prior to 223Ra-dichloride therapy and changes in uptake 12 weeks after the first cycle of therapy. Correlations were also observed between both 223Ra and 18F-fluoride uptake in lesions (r = 0.75) as well as between 223Ra absorbed dose and 18F-fluoride uptake (r = 0.96).

Conclusions

There is both inter-patient and intra-patient heterogeneity of absorbed dose estimates to metastatic lesions. A relationship between 223Ra lesion absorbed dose and subsequent lesion response was observed. Analysis of this small group of patients suggests that baseline uptake of 18F-fluoride in bone metastases is significantly correlated with corresponding uptake of 223Ra, the associated 223Ra absorbed dose and subsequent lesion response to treatment.

This article is freely available, click here to access the full text/PDF

  • Accepted: May 25, 2017
  • Online: Jun 13, 2017

Article Tools

eanm
EJNMMI Ad