Development and evaluation of a low-cost tofu-based ultrasound phantom and training methods for teaching...

Imaging phantoms simulate the ultrasonographic appearance of tissue and enable procedural skill training without animal use. Evidence for effective phantom-based training tools to teach ultrasound-guided fine needle aspiration (UG-FNA) in veterinary education is limited. This study developed and assessed an inexpensive tofu-based phantom simulating canine hepatic parenchyma with fluid-filled lesions that could be aspirated and compared three training methods for teaching UG-FNA to undergraduate veterinary students. Twelve veterinary professionals reviewed the phantom, and a six-item confidence questionnaire was developed and piloted alongside three training packages (face-to-face, video demonstration, written instructions). Thirty students were randomly allocated (n = 10 per group). Confidence was assessed pre- and post-training using generalised estimating equations with Bonferroni correction (corrected α = 0.0083). Competence was measured by volume of fluid aspirated and time to first successful aspiration, compared using Kruskal-Wallis analysis. Post-hoc power analysis demonstrated large effect sizes for competence outcomes (ε² = 0.200) and the primary confidence outcome (Cohen's f = 0.431). Professional review confirmed the phantom was realistic and suitable for teaching. Confidence improved significantly following all three methods (P < 0.001 for all items, surviving Bonferroni correction). Face-to-face training produced the greatest gains in confidence and competence; video demonstration achieved equivalent competence outcomes. Written instructions alone were insufficient. This is the first comparative evaluation of veterinary training methods for a UG-FNA phantom, demonstrating that this low-cost (£3.36 per unit) tofu-based model, paired with face-to-face or video instruction, effectively teaches UG-FNA, although findings should be interpreted as preliminary given the proof-of-concept design and small sample size. Effect size estimates are provided to inform future confirmatory studies.