TissueDB/Materials/Agar
License: CC-BY-SA-2.0 by Fred Miller, U of A System Division of Agriculture
Agar (also known as agar-agar, kanten, E406) is a gel-forming substance derived from red seaweed (algae). It is used in medical simulation for tissue phantom construction.[1][2][3][4] Agar does not require refrigeration once set, which is what makes it suitable for resource-limited and austere environments.[1]
Tissues
| Tissue | Visual | Tactile | Simulator | Notes |
|---|---|---|---|---|
| Vessels (vascular access) | A five percent by-mass agar gel, set at room temperature, produced an ultrasound image the source describes as remarkably resembling real tissue. Vessel analogues are water-filled latex Penrose drains and latex balloons embedded in the gel, not rigid tubing. The same source measured roughly 20 needle passes before the 5% agar model failed, against about 3 for gelatine.[1] | |||
| Muscle | 2% w/v agar + 2.1% w/v silica dioxide + 40% v/v evaporated milk — the source's stated muscle-tissue recipe. Note: the paper's own abstract prints the muscle silica figure as 2%, while its Results, Table 2 and Conclusions all print 2.1%; the 2.1% figure is used here because three places carry it against the abstract's one. Its companion brain recipe is 2% agar / 1.2% silica dioxide / 25% evaporated milk. The silica dioxide sets acoustic scattering and the evaporated milk sets attenuation.[2] The same three-part gel is characterised further by Drakos et al.[3] | |||
| Breast lesions | A "round pie" of black-ink coloured agar–agar gel with several green olives floating inside as the lesions, used for ultrasound skills and core-needle biopsy practice. The source lists as a limitation that the phantom does not realistically resemble the human breast — it is a lesion-finding target, not an anatomical model.[4] | |||
| Liver | Agar–albumin phantoms used to validate hepatic radiofrequency ablation simulation (17 phantoms).[5] |
Troubleshooting
- Procedures requiring elastic recoil — one source weighing casting materials for a laryngeal model states that "gelatin and agar are fragile and require a complicated mold to cast", and chose silicone instead.[6]
- Setting temperature — the sources differ by method and both are recorded rather than averaged. One sets 5% agar at room temperature (28 °C) in 15–20 minutes.[1] The other heats the mixture to 90 °C and cools it, the gel forming at about 50 °C.[3]
- Drying out is not the failure mode it is often assumed to be — the one source that measured it reports agar as resistant to spoiling and desiccation: a sample left uncovered for a week shrank about 0.5 cm with no cracking, and a covered sample did not shrink at all.[1]
Alternatives
| Alternative | Best For | Trade-offs |
|---|---|---|
| Gelatin Mix | Where a softer, more deformable gel is wanted | Animal-derived, and requires refrigeration both to set and to limit spoilage. |
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 Earle M, Portu G, DeVos E. Agar ultrasound phantoms for low-cost training without refrigeration. African Journal of Emergency Medicine 2016;6(1):18–23. DOI: 10.1016/j.afjem.2015.09.003. PMID 30456059. PMC PMC6233231.
- ↑ 2.0 2.1 Menikou G, Damianou C. Acoustic and thermal characterization of agar based phantoms used for evaluating focused ultrasound exposures. Journal of Therapeutic Ultrasound 2017;5:14. DOI: 10.1186/s40349-017-0093-z. PMID 28572977. PMC PMC5452295.
- ↑ 3.0 3.1 3.2 Drakos T, Antoniou A, Evripidou N, Alecou T, Giannakou M, Menikou G, Constantinides G, Damianou C. Ultrasonic attenuation of an agar, silicon dioxide, and evaporated milk gel phantom. Journal of Medical Ultrasound 2021;29(4):239–249. DOI: 10.4103/JMU.JMU_145_20. PMID 35127403. PMC PMC8772477.
- ↑ 4.0 4.1 Schmidt G, Gerlinger C, Endrikat J, Gabriel L, Müller C, Baus S, Volk T, Findeklee S, Solomayer EF, Hamza A, Ströder R. Teaching breast ultrasound skills including core-needle biopsies on a phantom enhances undergraduate student's knowledge and learning satisfaction. Archives of Gynecology and Obstetrics 2021;304(1):197–202. DOI: 10.1007/s00404-021-06016-8. PMID 33728537. PMC PMC8164585.
- ↑ Hoffer EK, Borsic A, Patel SD. Validation of software for patient-specific real-time simulation of hepatic radiofrequency ablation. Academic Radiology 2022;29(10):e219–e227. DOI: 10.1016/j.acra.2021.12.018. PMID 35039220. PMC PMC9276838.
- ↑ Lee M, Ang C, Andreadis K, Shin J, Rameau A. An open-source three-dimensionally printed laryngeal model for injection laryngoplasty training. The Laryngoscope 2021;131(4):E890–E895. DOI: 10.1002/lary.28952. PMID 32750164.
| Authors | Arturopelayo |
|---|---|
| License | CC-BY-SA-4.0 |
| Cite as | Arturopelayo (2026). "TissueDB/Materials/Agar". Appropedia. Retrieved August 22, 2026. |