RT Journal Article SR Electronic T1 EBONI: A tool for automated quantification of bone metastasis load in PSMA PET/CT JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.117.203265 DO 10.2967/jnumed.117.203265 A1 Jochen Hammes A1 Philipp Täger A1 Alexander Drzezga YR 2017 UL http://jnm.snmjournals.org/content/early/2017/12/13/jnumed.117.203265.abstract AB PSMA PET/CT has a high diagnostic accuracy for lesion detection in metastatic prostate cancer (MPC), including bone metastases. Novel therapeutic approaches require valid biomarkers for standardized disease staging, progression and therapy response. Here, we introduce EBONI (Evaluation of Bone Involvement), a software to automatically quantify bone metastasis load in PSMA PET/CT. Lesion quantity, mean and maximum lesional standardized uptake value (SUV), Z-Score and percentage of affected bone volume are determined. EBONI is open source and freely available. Methods: To validate EBONI, results of automated quantification of 38 PSMA PET/CT scans with different levels of bone involvement were compared to visual expert reading. Influence of SUV threshold (SUVT) and Hounsfield unit thresholds (HUT) were analyzed. Results: A very high correlation between bone lesion quantity as determined visually and automatically was found (SUVmax: r2=0.97, SUVmean: r2=0.88, lesion count: r2=0.97). HUT had no significant influence while a SUVT of 2.5 proved optimal for automated lesion quantification. The systematic error of false positive tissue misclassification is low, occurred mainly around the salivary and lacrimal gland and could easily be corrected for. There were no false negative ratings. Conclusion: EBONI-analysis is robust, quick (<3 minutes per scan) and 100% reproducible. It allows rater independent quantification of bone metastasis in MPC. It provides lesion quantification equivalent to visual assessment and complementary information. It can be easily implemented as an add-on to visual analysis of PSMA PET/CT scans and has the potential of reducing turnaround time.