RT Journal Article
SR Electronic
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.
FD Society of Nuclear Medicine
SP 214
OP 218
DO 10.2967/jnmt.117.192849
VO 45
IS 3
A1 Norikazu Matsutomo
A1 Masaaki Fukunaga
A1 Hideo Onishi
A1 Tomoaki Yamamoto
YR 2017
UL http://tech.snmjournals.org/content/45/3/214.abstract
AB This study aimed to determine whether a bismuth-coated latex shield (B-shield) could protect the eyes during brain SPECT/CT. Methods: A shield containing the heavy metal bismuth (equivalent to a 0.15-mm-thick lead shield) was placed over a cylindric phantom and the eyes of a 3-dimensional brain phantom filled with 99mTc 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 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 coefficients of variation did not significantly differ between phantoms with and without the B-shield, and the relative 99mTc 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 can help protect pediatric patients and patients with eye diseases who undergo SPECT imaging.