TY - JOUR T1 - Corneal Dose Reduction Using a Bismuth-coated Latex Shield over the Eyes During Brain SPECT/CT JF - Journal of Nuclear Medicine Technology JO - J. Nucl. Med. Technol. DO - 10.2967/jnmt.117.192849 SP - jnmt.117.192849 AU - Norikazu Matsutomo AU - Masaaki Fukunaga AU - Onishi Hideo AU - Tomoaki Yamamoto Y1 - 2017/05/01 UR - http://tech.snmjournals.org/content/early/2017/05/03/jnmt.117.192849.abstract N2 - Objective: This study aimed to determine whether a bismuth-coated latex shield (B-shield) could protect the eyes during brain SPECT/CT. Methods: A B-shield containing the heavy metal bismuth (0.15 mm lead equivalent) was placed over a cylindrical phantom and the eyes of a three-dimensional brain phantom filled with Tc-99m solution. Subsequently, phantoms with and without the B-shield were compared using SPECT/CT. The CT parameters were 30-200 mA and 130 kV. The dose reduction achieved by the B shield was measured using a pencil-shaped ionization chamber. The protective effects of the B shield were determined by evaluating relative radioactivity concentration as well as artifacts (changes in CT number), linear attenuation coefficients, and coefficients of variation (CV) on SPECT images. Results: The radiation doses with and without the B-shield were 0.14–0.77 and 0.36–1.93 mGy, respectively, and the B-shield decreased the average radiation dose by about 60%. The B-shield also increased the mean CT number, but only at locations just beneath the surface of the phantom. Streaks of higher density near the underside of the B-shield indicated beam hardening. Linear attenuation coefficients and the CVs did not significantly differ between phantoms with and without the B-shield, and the relative Tc-99m radioactivity concentrations were not affected. Conclusion: The B-shield decreased the radiation dose without affecting estimated attenuation correction or radioactivity concentrations. Although surface artifacts increased with the B-shield, the quality of the SPECT images was acceptable. B-shields could help to protect pediatric patients and patients with eye diseases who undergo SPECT imaging. ER -