Radiation dose for routine clinical adult brain CT: Variability on different scanners at one institution.

Published

Journal Article

OBJECTIVE: The purpose of this study was to determine, using an anthropomorphic phantom, whether patients are subject to variable radiation doses based on scanner assignment for routine CT of the brain. MATERIALS AND METHODS: Twenty metal oxide semiconductor field effect transistor dosimeters were placed in the brain of a male anthropomorphic phantom scanned three times with a routine clinical brain CT protocol on four scanners from one manufacturer in four configurations and on one 64-MDCT scanner from another manufacturer. Absorbed organ doses were measured for skin, cranium, brain, lens of the eye, mandible, and thyroid. Effective dose was calculated on the basis of the dose-length product recorded on each scanner. RESULTS: Organ dose ranges were as follows: cranium, 2.57-3.47 cGy; brain, 2.34-3.78 cGy; lens, 2.51-5.03 cGy; mandible 0.17-0.48 cGy; and thyroid, 0.03-0.28 cGy. Statistically significant differences between scanners with respect to dose were recorded for brain and lens (p < 0.05). Absorbed doses were lowest on the single-detector scanner. In the comparison of MDCT scanners, the highest doses were found on the 4-MDCT scanner and the dual-source 64-MDCT scanner not capable of gantry tilt. Effective dose ranged from 1.22 to 1.86 mSv. CONCLUSION: According to the phantom data, patients are subject to different organ doses in the lens and brain depending on scanner assignment. At our institution with existing protocols, absorbed doses at brain CT are lowest with the single-detector CT scanner, followed by MDCT scanners capable of gantry tilt. On scanners without gantry tilt, CT of the brain should be performed with careful head positioning and shielding of the orbits. These precautions are especially true for patients who need repeated scanning and for pediatric patients.

Full Text

Duke Authors

Cited Authors

  • Jaffe, TA; Hoang, JK; Yoshizumi, TT; Toncheva, G; Lowry, C; Ravin, C

Published Date

  • August 2010

Published In

Volume / Issue

  • 195 / 2

Start / End Page

  • 433 - 438

PubMed ID

  • 20651201

Pubmed Central ID

  • 20651201

Electronic International Standard Serial Number (EISSN)

  • 1546-3141

International Standard Serial Number (ISSN)

  • 0361-803X

Digital Object Identifier (DOI)

  • 10.2214/ajr.09.3957

Language

  • eng