RT Journal Article
SR Electronic
T1 Lens Exposure during Brain Scans Using Multidetector Row CT Scanners: Methods for Estimation of Lens Dose
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 822
OP 826
DO 10.3174/ajnr.A1946
VO 31
IS 5
A1 Suzuki, S.
A1 Furui, S.
A1 Ishitake, T.
A1 Abe, T.
A1 Machida, H.
A1 Takei, R.
A1 Ibukuro, K.
A1 Watanabe, A.
A1 Kidouchi, T.
A1 Nakano, Y.
YR 2010
UL http://www.ajnr.org/content/31/5/822.abstract
AB BACKGROUND AND PURPOSE: Some recent studies on radiation lens injuries have indicated much lower dose thresholds than specified by the current radiation protection guidelines. The purpose of this research was to measure the lens dose during brain CT scans with multidetector row CT and to assess methods for estimating the lens dose. MATERIALS AND METHODS: With 8 types of multidetector row CT scanners, both axial and helical scans were obtained for the head part of a human-shaped phantom by using normal clinical settings with the orbitomeatal line as the baseline. We measured the doses on both eyelids by using an RPLGD during whole-brain scans including the orbit with the starting point at the level of the inferior orbital rim. To assess the effect of the starting points on the lens doses, we measured the lens doses by using 2 other starting points for scanning (the orbitomeatal line and the superior orbital rim). RESULTS: The CTDIvols and the lens doses during whole-brain CT including the orbit were 50.9–113.3 mGy and 42.6–103.5 mGy, respectively. The ratios of lens dose to CTDIvol were 80.6%–103.4%. The lens doses decreased as the starting points were set more superiorly. The lens doses during scans from the superior orbital rim were 11.8%–20.9% of the doses during the scans from the inferior orbital rim. CONCLUSIONS: CTDIvol can be used to estimate the lens dose during whole-brain CT when the orbit is included in the scanning range. CTDICT dose indexCTDIvolsvolume CT dose indicesDIORlens dose during whole-brain scanning from the inferior orbital rimDOMlens dose during scanning from the orbitomeatal lineDSORlens dose during scanning from the superior orbital rimICRPInternational Commission on Radiological ProtectionmAseffmAs divided by helical pitchRPLGDradiophotoluminescent glass dosimeter