Assessment of response of brain metastases to radiotherapy by PET imaging of apoptosis with 18F-ML-10
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Early assessment of tumor response to therapy is vital for treatment optimization for the individual cancer patient. Induction of apoptosis is an early and nearly universal effect of anticancer therapies. The purpose of this study was to assess the performance of 18F-ML-10, a novel PET radiotracer for apoptosis, as a tool for the early detection of response of brain metastases to whole-brain radiation therapy (WBRT).
Materials and methods
Ten patients with brain metastases treated with WBRT at 30 Gy in ten daily fractions were enrolled in this trial. Each patient underwent two 18F-ML-10 PET scans, one prior to the radiation therapy (baseline scan), and the second after nine or ten fractions of radiotherapy (follow-up scan). MRI was performed at 6–8 weeks following completion of the radiation therapy. Early treatment-induced changes in tumor 18F-ML-10 uptake on the PET scan were measured by voxel-based analysis, and were then evaluated by correlation analysis as predictors of the extent of later changes in tumor anatomical dimensions as seen on MRI scans 6–8 weeks after completion of therapy.
In all ten patients, all brain lesions were detected by both MRI and the 18F-ML-10 PET scan. A highly significant correlation was found between early changes on the 18F-ML-10 scan and later changes in tumor anatomical dimensions (r = 0.9).
These results support the potential of 18F-ML-10 PET as a novel tool for the early detection of response of brain metastases to WBRT.
KeywordsPositron emission tomography Response assessment Whole-brain radiation therapy Brain metastases Apoptosis
This trial was financially supported by Aposense Ltd.
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