Prospective inter- and intra-tracer repeatability analysis of radiomics features in [68Ga]Ga-PSMA-11 and [18F]F-PSMA-1007 PET scans in metastatic prostate cancer

Jake Kendrick, Roslyn Francis, Ghulam Mubashar Hassan, Pejman Rowshan Farzad, Jeremy S.L. Ong, Robert Jeraj, Nathaniel Barry, Tammy Hagan, Martin Ebert

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This study aimed to quantify both the intra- and inter tracer repeatability of lesion-level radiomics features in [68Ga]Ga-PSMA-11 and [18F]F-PSMA-1007 PET scans.
Eighteen patients with metastatic prostate cancer (mPCa) were prospectively recruited for the study and randomised to one of three test-retest groups: (i) intra tracer [68Ga]Ga-PSMA-11 PET, (ii) intra tracer [18F]F-PSMA-1007 PET or (iii) inter tracer between [68Ga]Ga-PSMA-11 and [18F]F-PSMA-1007 PET. Four conventional PET metrics (SUVmax, SUVmean, SUVtotal and volume) and 107 radiomics features were extracted from 75 lesions and assessed using the repeatability coefficient (RC) and the ICC. Radiomic feature repeatability was also quantified after the application of 16 filters to the PET image.
Test-retest scans were taken a median of 5 days apart (range: 2–7 days). SUVmean demonstrated the lowest RC limits of the conventional features, with RCs of 7.9%, 14.2 and 24.7% for the [68Ga]Ga-PSMA-11 PET, [18F]F-PSMA-1007 PET, and inter tracer groups, respectively. 69%, 66 and 9% of all radiomics features had good or excellent ICC values (ICC ≥0.75) for the same groups. Feature repeatability therefore diminished considerably for the inter tracer group relative to intra tracer groups.
In this study, robust biomarkers for each tracer group that can be used in subsequent clinical studies were identified. Overall, the repeatability of conventional and radiomic features were found to be substantially lower for the inter tracer group relative to both intra tracer groups, suggesting that assessing patient response quantitatively should be done using the same radiotracer where possible.
Original languageEnglish
Article number20221178
Number of pages11
JournalThe British journal of radiology
Issue number1152
Early online date24 Oct 2023
Publication statusPublished - Dec 2023

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