Biological Tissue Modeling with Agar Gel Phantom for Radiation Dosimetry of <sup>99m</sup>Tc

Abstract

The biological tissue has been mimicked and replaced by other materials, which have shown certain radiological similarity determined by attenuation coefficient (μ), density and atomic number. Specifically, in molecular imaging and radiation therapy have been developed multifunctional radiopharmaceuticals which contain beta/gamma and/or light emitters to chronic degenerative diseases treatment. Therefore, it is necessary to develop phantoms that allow optical and radiometric characterization. Since the agar gel has shown to be a medium which allows to model biological tissue in phototherapy studies, the aim of this study is to determine whether the agar gel may be used as biological tissue substitutes in 99m Tc dosimetry. Agar gel was prepared to 1% and 2.3% (water:agar) and its radiologicalproperties as: linear attenuation coefficient obtained by narrow beam geometry and XCOM software, density and effective atomic number (Z eff) were determined. Using the determined μ, photontransmission was calculated by Monte Carlosimulation. The 99m Tc source region was immersed in a water phantom, two source regions were used, one source region was filled with water and another with agar gel. For both cases; the cumulated activity ( A) by conjugate view method, the absorbed doseper unitcumulated activity (S) and absorbed dose (D) were determined. The 2.3% concentration gel consistency facilitated its handling during a bigger irradiation time. A 0.151 0.02 1 cm

Acoustic Attenuation and Dispersion in Fatty Tissues and Tissue Phantoms Influencing Ultrasound Biomedical Imaging

“…Agar powder, 100% nature seaweed by ECO-TASTE, was used to make agar gels with 5 and 10 wt % concentrations. For 5 wt % agar gels, 5 g of agar powder was dissolved in 100 g of deionized and degassed water, and the mixture was heated up to the boiling point and kept for 2 min with constant stirring . The mixture was then cooled down at room temperature for 24 h. We used the same six-well plates to mold the agar gel phantom.…”

“…This study examined the acoustic properties, especially the dispersion coefficient of four widely used soft tissue-mimicking materials: gelatin, agar, silicone rubber, and agarose, using the proposed technique. Gelatin gels and agar gels are the earliest soft tissue-mimicking material for ultrasound imaging due to their closeness to soft tissue mechanical and acoustic properties, relatively low cost, and convenience. , Agarose is a natural polysaccharide polymer with unique biocompatibility, thermoreversible gelation behavior, and physiochemical feature used for tissue engineering applications. , Silicone rubber-based gels are mainly for skeletal muscle and breast-related research. , Moreover, researchers mix other ingredients into those gels to tune the acoustic properties. This study will also investigate the acoustic changes induced by adding evaporated milk into gelatin or mineral oil into silicone rubber at different concentrations.…”

Heating, Efficacy and Dose of Local Hyperthermia

“…The phantom (on the insert) volume is easy to be calculated ≈1.4 liter, which using the agar density [24] is 1.4 kg mass. So the absorbed power in this entire phantom is 70 × 1.4 = 98 W.…”

Dynamic nuclear polarization studies of nitroxyl spin probes in agarose gel using Overhauser‐enhanced magnetic resonance imaging

“…Agarose is a neutral and toxic‐free material, which is derived from seaweed and used in the construction of phantoms. Several research groups described the use of agarose gels as tissue equivalent material . The use of tissue‐equivalent phantoms made of this material will improve the quality of imaging.…”

“…Several research groups described the use of agarose gels as tissue equivalent material. [31][32][33] The use of tissueequivalent phantoms made of this material will improve the quality of imaging. The simplest and most versatile tissuemimicking phantom media are agarose gels doped with paramagnetic material.…”