Purpose: The aim of this study was to investigate the biodistribution of (super-)selective trans-arterial radioembolization (TARE) with holmium-166 microspheres (¹⁶⁶Ho-MS), when administered as adjuvant therapy after RFA of HCC 2–5 cm. The objective was to establish a treatment volume absorbed dose that results in an absorbed dose of ≥ 120 Gy on the hyperemic zone around the ablation necrosis (i.e., target volume). Methods: In this multicenter, prospective dose-escalation study in BCLC early stage HCC patients with lesions 2–5 cm, RFA was followed by (super-)selective infusion of ¹⁶⁶Ho-MS on day 5–10 after RFA. Dose distribution within the treatment volume was based on SPECT-CT. Cohorts of up to 10 patients were treated with an incremental dose (60 Gy, 90 Gy, 120 Gy) of ¹⁶⁶Ho-MS to the treatment volume. The primary endpoint was to obtain a target volume dose of ≥ 120 Gy in 9/10 patients within a cohort. Results: Twelve patients were treated (male 10; median age, 66.5 years (IQR, [64.3–71.7])) with a median tumor diameter of 2.7 cm (IQR, [2.1–4.0]). At a treatment volume absorbed dose of 90 Gy, the primary endpoint was met with a median absorbed target volume dose of 138 Gy (IQR, [127–145]). No local recurrences were found within 1-year follow-up. Conclusion: Adjuvant (super-)selective infusion of ¹⁶⁶Ho-MS after RFA for the treatment of HCC can be administered safely at a dose of 90 Gy to the treatment volume while reaching a dose of ≥ 120 Gy to the target volume and may be a favorable adjuvant therapy for HCC lesions 2–5 cm. Trial registration: Clinicaltrials.gov NCT03437382.

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Introduction: Autonomous delivery robots are a promising alternative for last-mile delivery. To realise successful implementation of delivery robots in public spaces, it is important to study the interaction between robots and the traffic environment. The traffic environment includes the physical infrastructure and the objects using it like cars and people.

Methods: This research proposes an assessment method to determine the readiness of a traffic environment for autonomous delivery robots. A conceptual model is proposed that includes the factors that determine this so-called “roboreadiness”. The two key components of the model are the performance of the robot in the traffic environment and its social acceptance. A real-life experimental test case, expert interviews, and a survey are used to refine and validate the framework.

Results: The real-life test case showed for the basic variant a sufficient level both on performance and social acceptance. All other variants such as pillars, road narrowing, and bends did not lead to sufficient performance or social acceptance levels.

Discussion: The main outcome of this research is an assessment framework which allows to quantitatively assess traffic performance and social acceptance of sidewalk automated delivery robots. Suggestions for future work include further detailing and elaboration of the approach, scaling up experiments, and researching the possible influence of social acceptance on traffic performance.@en