To characterize the image quality and dose level of a cone-beam CT (CBCT) scanner dedicated to maxillo-facial intra-surgical navigation. Acquisition protocols for head imaging of average pediatric and adult patients were investigated. The detector response curve and the modulation transfer function (MTF) were assessed. The 3D image quality was evaluated using a commercial Catphan604 phantom in terms of accuracy of Hounsfield Unit (HU) estimates and slice uniformity. The MTF and the noise power spectrum (NPS) were assessed over the 3D reconstructed images. The weighted cone-beam dose index (CBDI_w) was used for dosimetric benchmarking, and TLD chips placed in two anthropomorphic phantoms provided insight into the patient dose distribution. The detector exhibited a response curve with a double natural logarithmic behavior and spatial resolutions up to 6.3 mm^-1. The 3D spatial resolution ranged from 0.70 mm^-1 at the scanner isocenter, for the pediatric protocol, to 0.46 mm^-1 at 7 cm from the isocenter for the adult protocol. Due to beam hardening and the scatter, discrepancies between expected and measured HU were observed, in particular for positive HU values (i.e. those for acrylic, bone, delrin and teflon inserts). The CBDI_w and dose distribution within anthropomorphic phantoms provided a dosimetric benchmark for the scanner. This study characterized a CBCT scanner in maxillo-facial surgery navigation. The findings support the definition of quality assurance protocols, providing methodologies and reference values for image quality and dose, while also highlighting limitations in spatial resolution and accuracy relevant for quantitative evaluations in clinical practice.

Background: Peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE has become a cornerstone in the management of neuroendocrine tumors (NETs). However, the efficiency of this targeted therapy is highly dependent on the radiopharmaceutical drug delivery system and its infusion kinetics, which influence systemic biodistribution and therapeutic efficacy. This study evaluates various gravity-based infusion fluid dynamics to optimize the drug delivery profile, ensuring standardized delivery while minimizing residual activity. Methods: A retrospective analysis of 127 administrations of ¹⁷⁷Lu-DOTATATE (7.4 GBq per cycle) was conducted across 35 patients with NETs to assess vial dilution kinetics. Four distinct infusion rate (IR) strategies were compared to evaluate mass balance and delivery efficiency: constant infusion rate (1-IR); a single rate increase at 10 min (2-IR); two rate increases at 10 and 30 min (3-IR); and three rate increases at 10, 30, and 40 min (4-IR). Results: Stepwise increases in the IR significantly accelerated the vial clearance kinetics and reduced radiopharmaceutical stagnation within the infusion lines. Successful delivery of the target dose (98% of the pre-infusion activity measured in each specific vial) was achieved in 56% of cases with the 1-IR protocol (9 injections) and increased to 87% with 2-IR (45 injections), 97% with 3-IR (60 injections), and 100% with 4-IR (13 injections). Conclusions: Modulating fluid dynamics through stepwise IR protocols significantly enhances radiopharmaceutical delivery efficiency. The 3-IR protocol offers a favorable balance between procedural efficiency and clinical safety.