Prospective Clinical Assessment of Ultrasound-Assisted Radiopharmaceutical Imaging Under Anesthesia for Oncologic Evaluation

Background: Ultrasound (US) is widely used in oncology, yet prospective clinical evidence for integrating US into radiopharmaceutical positron emission tomography/computed tomography (PET/CT) workflows remains limited. We assessed whether a standardized periprocedural US step under anesthesia improves lesion detectability and quantitative conspicuity without compromising safety. Methods: In a prospective single-arm trial, 39 patients were enrolled and 38 completed US-assisted PET/CT. Under general anesthesia with continuous monitoring, US was applied to the target region immediately before radiotracer administration, followed by whole-body PET/CT under uninterrupted anesthesia. Two blinded nuclear medicine physicians interpreted paired standard versus US-assisted datasets, scoring lesion detection and 5-point confidence. Primary endpoints were within-patient change in detection and confidence. Secondary endpoints included standardized uptake value/tumor-to-background ratio (TBR) metrics, management change, and Common Terminology Criteria for Adverse Events (CTCAE)-graded safety. Paired McNemar and Wilcoxon signed-rank tests were used; κ quantified interreader agreement. Results: US assistance increased lesion detection and improved reader confidence, with higher paired TBR and most patients showing clinically meaningful TBR gains. Management changed in 12/38 (31.6%). No CTCAE grade ≥3 events occurred; vitals remained stable, and stop criteria were not triggered. Conclusions: US integration into PET/CT under anesthesia was feasible and safe, improving imaging performance and clinical decision impact, aligning with clinical trial and risk-focused US oncology priorities.