Gellan gum gel tissue phantoms and gel dosimeters with tunable electrical, mechanical and dosimetric properties

Gellan gum gels have been proposed as tissue- and water-mimicking materials (phantoms) applied in medical imaging and radiotherapy dosimetry. Phantoms often require ionic additives to induce desirable electrical conductivity, resistance to biological spoilage, and radical scavenging properties. However, gellan gum is strongly crosslinked by the typically used sodium salts, forming difficult-to-work with gels with reduced optical clarity. Herein we investigated lithium and tetramethylammonium chloride to induce the required electrical conductivity while maintaining optical clarity; lithium formate and methylparaben were used as a radical scavenger and antimicrobial additive, respectively. Using a multifactorial design of experiments, we studied and modeled the electrical and mechanical properties and liquid expulsion (syneresis) properties of the gels. Finally, by the addition of a radiation-sensitive tetrazolium salt, dosimeters with favorable properties were produced. The results described herein may be used to prepare tissue phantoms and dosimeters with tuned electrical, mechanical, and dosimetric properties.