Fabrication of anthropomorphic thyroid-neck phantom for dosimetry study in nuclear medicine

摘要

The aim of this study was to fabricate an anthropomorphic thyroid-neck phantom for dosimetry study in nuclear medicine. The main structures of the anthropomorphic phantom comprise of neck, thyroid, trachea, oesophagus, cervical bone and spinal canal. Several slots for Optically Stimulated Luminescent Dosimeter (OSLD) for each organ was also fabricated to measure the absorbed dose received by thyroid and other organs at risk. The phantom was made from paraffin wax and sodium chloride (NaCl) compounds. The fabricated anthropomorphic phantom was then tested by administrating Tc-99m with an activity of 0.3 mCi and 2.0 mCi in thyroid and neck phantoms respectively. The phantom was scanned for 30 min with diagnostic thyroid imaging of SPECT to observe the distribution of Tc-99m. A comparison analysis between mass attenuation coefficient of samples and mass attenuation coefficient of human tissue obtained from ICRU report-44 was performed to validate the mass attenuation coefficient of samples obtained in this study. Relative percentage differences of mass attenuation coefficients of samples obtained from experimental and XCOM stimulation values were evaluated respectively. The absorbed dose to thyroid and other organs at risk was evaluated from OSLDs at 6 h (first half life), 12 h (second half life) and 24 h (fourth half-life) after the injection of Tc-99m.