Comparison of low-cost phantoms for ultrasound-guided fine-needle aspiration biopsy training

Abstract

Introduction: Phantoms and simulators are widely accepted methods to gain valuable experience and confidence for inexperienced trainees prior to seeing their patient and for refining their skills. A phantom model that is durable, simple, and inexpensive to produce and use would be ideal to train practitioners in ultrasound-guided fine-needle aspiration biopsy (USFNA) technique.

Materials and methods: In this study, we systematically compared several low-cost phantom models including gelatin, extra firm tofu, canned cooked pork, ballistics gel, and chicken breast for their haptic properties, echogenicity, teaching utility, and overall performance based on a Likert scale (1-5; 5 = best). Nine cytopathologists and cytopathology fellows who perform FNA regularly evaluated these models and completed the survey.

Results: The gelatin phantom, with a gelatin to water ratio of 1:8 by weight, was found to be the best for USFNA practice and overall performance, followed by the 1:10 gelatin phantom. Tofu and chicken breast phantoms were also good low-cost alternatives that needed only a few minutes of total preparation time.

Conclusions: Low-cost, homemade phantoms can serve as excellent alternatives to commercial phantoms for practicing and teaching USFNA.

Keywords: Cytopathology; Fine needle aspiration biopsy; Phantom; Training; Ultrasound.

Figure 1:

Images of gelatin phantom model from above (A) and cross section (B) to illustrate the placement of targets.

Figure 2:

Median scores of each homemade phantom models for haptic quality (A), echogenic quality (B), usefulness in USFNA practice (C), as well as overall impression (d) in USFNA training.

Figure 3:

Illustration of the echogenic quality of phantom models for visualizing various targets and needle path in each homemade phantoms on ultrasound images. A) Ballistics gel with a craft pom pom. B) Phantom made 1:8 gelatin to water ratio with a pitted olive. C) phantom made 1:10 gelatin to water ratio with a pitted olive. D) Chicken breast with a pitted olive. E) extra firm tofu with a cooked black bean. F) Canned cooked pork with a cooked black bean.

Figure 4:

Illustration of the echogenic quality of a commercial phantom with numerous needle tracks obscuring a target (A) and a ballistics gel phantom with abundant air bubbles obscuring a target and needle path (B).

Figure 5:

Homemade and commercial phantom models compared. A) From left, clockwise, commercial phantom, canned cooked pork, chicken breast, extra firm tofu. B) Ballistics gel phantom with craft pom poms as targets. C) Phantom made of 1:10 gelatin to water ratio with green food coloring, pitted olives, and cooked black beans. D) Phantom made of 1:8 gelatin to water ratio with blue food coloring, pitted olives, and cooked black beans.