Agar ultrasound phantoms for low-cost training without refrigeration

Ultrasound is a technique that can be utilised to augment procedures to increase their safety and efficacy, but requires that health professionals be trained to use this imaging modality before it can be implemented. With the extremely high cost of manufactured phantoms, homemade alternatives are popular substitutes. Gelatine is commonly used as a matrix to suspend analogues and mimic tissue, but other substrates like ground meat can also be used. Both of these substrates require refrigeration and are subject to spoiling. Our research was designed to evaluate whether agar models would be superior to traditional Gelatine models in their sustainability and whether they would produce ultrasound images adequate for training.

Agar models of varying formulas (percent agar by weight with certain additives varied) were tested for acceptable fidelity to real tissue, ultrasound image quality, and durability compared to gelatine models and human tissue.

A five percent by-mass agar model augmented with small amounts of suspended wheat flour presented as a model that could generate an ultrasound image that remarkably resembled that of real tissue. This agar model does not require refrigeration, is resistant to spoiling and desiccation, mimics tissue texture well, is durable enough to withstand high-volume training, and can be recycled to make new models.

Agar phantoms are easy to make, do not require refrigeration, and have multiple distinct advantages over gelatine models for ultrasound training in austere conditions.