Development of an ultrasound training phantom of the thyroid gland: physical characteristics of TMM.

The objective of this research was to synthesize a thyroid phantom with ultrasound properties similar to those of tissue-mimicking materials (TMM). This was done so that an ultrasound thyroid-training phantom could be developed. A polymer urethane TMM was made by using the following materials: C, CCR, TiO(2), silver, tungsten, and graphite, in the hope that it would have the same properties as soft tissue. To confirm this similarity, several tests were undertaken, including penetration, gray scale, propagated speed, and attenuation back comparison. The results of this study were as follows: (1) The propagated speed of C, CCR, and graphite-type TMM were 1,460-1,580 m/s. Attenuation was 0.5-0.7 dB/cm/MHz, and a homogeneous echo pattern similar to that of thyroid gland was noted. (2) The TiO(2) TMM seemed similar to that of thyroid even in low echo. The surrounding area also showed similar patterns. (3) The silver TMM showed an echo pattern similar to that of prostate. (4) The tungsten TMM showed a visible heterogeneous echo pattern. (5) The C-type TMM was compared with human thyroid and also tested via ultrasound imaging. It is hoped that this research will be useful in the future in ultrasonography training and in providing a better thyroid-training phantom and phantoms of other organs.