Design and manufacturing of anthropomorphic thyroid-neck phantom for use in nuclear medicine centres in Chile

Abstract

Anthropomorphic phantoms are used in nuclear medicine for imaging quality control, calibration of gamma spectrometry system for the study of internal contamination with radionuclides and for internal dosimetric studies. These are constructed of materials that have radiation attenuation coefficients similar to those of the different organs and tissues of the human body. The material usually used for the manufacture of phantoms is polymethyl methacrylate. Other materials used for this purpose are polyethylene, polystyrene and epoxy resin. This project presents the design and manufacture of an anthropomorphic thyroid-neck phantom that includes the cervical spine, trachea and oesophagus, using a polyester resin (ρ = 1.1 g cm(-3)). Its linear and mass attenuation coefficients were experimentally determined and simulated by means of XCOM software, finding that this material reproduces the soft tissue ICRU-44 in a range of energies between 80 keV and 11 MeV, with less than a 5 % difference.

A Neck-Thyroid Phantom with Small Sizes of Thyroid Remnants for Postsurgical I-123 and I-131 SPECT/CT Imaging

“…In previous studies, either water containers with hollow inserts down to 5 mL were used to simulate remnants [8][9][10] or neck-thyroid phantoms with hollow thyroid glands with or without other anatomical structures [12][13][14][15] were used in Tc-99m and I-131 SPECT studies. In this study, a neck-thyroid phantom with different sizes of small (0.5-10 mL) thyroid remnants at clinically relevant positions, including all relevant anatomical structures, and able to simulate different background-to-remnant activity ratios, was developed to specifically study postsurgical thyroid-remnant SPECT/CT imaging procedures.…”

“…Physical phantoms with thyroid glands have been developed and evaluated in previous studies [12][13][14][15]. In particular, solid cylindrical phantoms, with and without other structures such as the trachea, esophagus and cylindrical cervical spine, and a detachable section of the thyroid gland have been developed and evaluated using Tc-99m or I-131 SPECT images [14,15].…”

“…Physical phantoms with thyroid glands have been developed and evaluated in previous studies [12][13][14][15]. In particular, solid cylindrical phantoms, with and without other structures such as the trachea, esophagus and cylindrical cervical spine, and a detachable section of the thyroid gland have been developed and evaluated using Tc-99m or I-131 SPECT images [14,15]. Alqahtani et al [15] developed a hollow head-neck phantom which includes the trachea, cylindrical cervical spine, a non-detachable thyroid gland and different sizes of sentinel lymph nodes.…”

Design and Production of Two-Piece Thyroid-Neck Phantom by the Concurrent Use of Epoxy Resin and Poly(Methyl Methacrylate) Soft Tissue Equivalent Materials

“…The radioactivity of such sources can be measured using quantitative imaging, direct measurement in the whole body or specific organs, or by indirect measurement in biological specimens especially in urine. The absorbed dose in the target tissue can also be calculated by Monte Carlo simulations [ 5 - 7 ] or Kernel Point doses [ 8 ].…”

“…The phantom can be used in the calibration of gamma camera for in-vivo measurements in order to determine patient-specific therapeutic activity. It can be further used to control the quality of gamma spectrometry system utilized in nuclear medicine [ 8 ].…”