Development of a human-tissue-like phantom for 3.0-T MRI.

Purpose: A 3.0-T MRI phantom having human-tissue-equivalent relaxation times was developed. Methods: The ingredients of the phantom are carrageenan (for gelatinization), GdCl3 (as a T1-relaxation modifier), agarose (as a T2-relaxation modifier), and NaN3 (as an antiseptic agent). Numerous samples with varying concentrations of GdCl3 and agarose were prepared, and T1 and T2 were measured using 3.0-T MRI. Results: Relaxation times of the phantom samples ranged from 395 to 2601 ms for T1 values and 29 to 334 ms for T2 values. Based on the measured results, empirical formulae were devised to express the relationships between the concentrations of relaxation modifiers and relaxation times. Conclusions: Adjustment of GdCl3 and agarose concentrations allows arbitrary setting of relaxation times, and the creation of a phantom that can mimic relaxation times of human-tissue. Carrageenan is considered the most suitable as a gelling agent for an MRI phantom, as it permits the relatively easy and inexpensive production of a large phantom such as for the human torso, and which can be easily shaped with a knife.