Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding

Ming Fang Lin, Chia Yuen Chen, Yuan Hao Lee, Chia Wei Li, Leo E. Gerweck, Hao Wang, Wing P. Chan

Research output: Contribution to journalArticle

Abstract

Background: Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose: To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods: An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results: The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. Conclusion: Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.

Original languageEnglish
JournalActa Radiologica
DOIs
Publication statusAccepted/In press - Jan 1 2018

Fingerprint

Crystalline Lens
Antimony
Bismuth
Lenses
Nasal Bone
Barium Sulfate
Head
Tomography
Signal-To-Noise Ratio
Artifacts
Radiation
Noise
Orbit
Nose
Bone and Bones
Water

Keywords

  • Computed tomography
  • eye shields
  • image quality
  • radiation dose
  • radiation protection

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

Cite this

Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding. / Lin, Ming Fang; Chen, Chia Yuen; Lee, Yuan Hao; Li, Chia Wei; Gerweck, Leo E.; Wang, Hao; Chan, Wing P.

In: Acta Radiologica, 01.01.2018.

Research output: Contribution to journalArticle

@article{1dba9c63462646b5a62b0e816f4fa311,
title = "Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding",
abstract = "Background: Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose: To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods: An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results: The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0{\%} and 35.6{\%} reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6{\%} in the extraorbital region and the CNR by 7.2{\%} between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2{\%} and 27.2{\%}, respectively. Conclusion: Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.",
keywords = "Computed tomography, eye shields, image quality, radiation dose, radiation protection",
author = "Lin, {Ming Fang} and Chen, {Chia Yuen} and Lee, {Yuan Hao} and Li, {Chia Wei} and Gerweck, {Leo E.} and Hao Wang and Chan, {Wing P.}",
year = "2018",
month = "1",
day = "1",
doi = "10.1177/0284185118770894",
language = "English",
journal = "Acta Radiologica",
issn = "0284-1851",
publisher = "SAGE Publications Ltd",

}

TY - JOUR

T1 - Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding

AU - Lin, Ming Fang

AU - Chen, Chia Yuen

AU - Lee, Yuan Hao

AU - Li, Chia Wei

AU - Gerweck, Leo E.

AU - Wang, Hao

AU - Chan, Wing P.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Background: Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose: To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods: An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results: The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. Conclusion: Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.

AB - Background: Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose: To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods: An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results: The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. Conclusion: Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.

KW - Computed tomography

KW - eye shields

KW - image quality

KW - radiation dose

KW - radiation protection

UR - http://www.scopus.com/inward/record.url?scp=85045842885&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85045842885&partnerID=8YFLogxK

U2 - 10.1177/0284185118770894

DO - 10.1177/0284185118770894

M3 - Article

AN - SCOPUS:85045842885

JO - Acta Radiologica

JF - Acta Radiologica

SN - 0284-1851

ER -