The purpose of this study was to compare radiation dose estimates between state -of-the-art interventional fluoroscopy systems in vitro and in clinical cases. In vitro analysis included verifying system-reported air kerma rates (AKR; with a Radcal detector) and comparing AKR for simulated patient thicknesses (20-40cm) for different dose modes and clinical protocols on Philips 'AlluraClarity' (different generations) and Siemens 'Artis Q' systems (n=4). After IRB approval, system-reported radiation dose estimates i.e., cumulative air kerma (CAK) at the interventional reference point and kerma-area product (KAP), were extracted for interventional cases performed over a 16-month period from GE Centricity RIS and compared split by procedure type. Next, CAK and KAP for patients with metastatic uveal melanoma undergoing repeat chemo/immuno-embolization (potentially high radiation dose procedure) of the same liver lobe by the same physician on AlluraClarity and Artis Q were compared, accounting for differences in patient positioning, reference locations and digital acquisitions obtained from structured dose reports using DoseMetrix (Primordial) and CareAnalytics (Siemens). IBM's SPSS Statistics was used for parametric and non-parametric tests (with Bonferroni corrections for multiple comparisons ). In vitro analysis showed significant differences (p < 0.05) in verified AKR (25-45 mGy/min lower with AlluraClarity for thicknesses of 30-40 cm). Clinical data analysis comprised of 5113 cases; significant differences for CAK and KAP were seen for certain procedure (p < 0.05), with significantly lower values for AlluraClarity systems (differences in median: 34-61%). Subset analysis included 61 patients treated on both systems at different time points; accounting for differences in other parameters, CAK and KAP were significantly lower for AlluraClarity systems (p < 0.02; median for CAK lower by 44% and for KAP by 27%). Radiation dose differences observed in vitro between the AlluraClarity and Artis Q systems were reflected in clinical cases (even for same patients undergoing the same procedure). When the differences were significant, AlluraClarity systems showed relatively lower radiation utilization.