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Effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral pediatric and adult CT angiography: a phantom study.
Invest Radiol. 2013 Apr; 48(4):192-9.IR

Abstract

OBJECTIVES

The aim of the present phantom study was to investigate the effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral computed tomographic (CT) angiographic examinations of pediatric and adult individuals.

MATERIALS AND METHODS

Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old children and the RANDO phantom that simulates the average adult individual were used. Cylindrical vessels were bored along the brain-equivalent plugs of each physical phantom. To simulate the brain vasculature, vessels of 0.6, 1, 2, and 3 mm in diameter were created. These vessels were filled with contrast medium (CM) solutions at different iodine concentrations, that is, 5.6, 4.2, 2.7, and 1.4 mg I/mL. The phantom heads were scanned at 120, 100, and 80 kV. The applied quality reference tube current-time product values ranged from a minimum of 45 to a maximum of 680. The CT acquisitions were performed on a 16-slice CT scanner using the automatic exposure control system. Image quality was evaluated on the basis of image noise and contrast-to-noise ratio (CNR) between the contrast-enhanced iodinated vessels and the unenhanced regions of interest. Dose reduction was calculated as the percentage difference of the CT dose index value at the quality reference tube current-time product and the CT dose index at the mean modulated tube current-time product.

RESULTS

Image noise that was measured using the preset tube current-time product settings varied significantly among the different phantoms (P < 0.0001). Hounsfield unit number of iodinated vessels was linearly related to CM concentration (r² = 0.907) and vessel diameter (r² = 0.918). The Hounsfield unit number of iodinated vessels followed a decreasing trend from the neonate phantom to the adult phantom at all kilovoltage settings. For the same image noise level, a CNR improvement of up to 69% and a dose reduction of up to 61% may be achieved when CT acquisition is performed at 80 kV compared with 120 kV. For the same CNR, a reduction by 25% of the administered CM concentration may be achieved when CT acquisition is performed at 80 kV compared with 120 kV.

CONCLUSIONS

In cerebral CT angiographic studies, appropriate adjustment of the preset tube current-time product settings is required to achieve the same image noise level among participants of different age. Cerebral CT angiography at 80 kV significantly improves CNR and significantly reduces radiation dose. Moreover, at 80 kV, a considerable reduction of the administered amount of the CM may be reached, thus reducing potential risks for contrast-induced nephropathy.

Authors+Show Affiliations

Department of Medical Physics, University Hospital of Heraklion, Crete, Greece. apapadak@edu.med.uoc.grNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23344518

Citation

Papadakis, Antonios E., et al. "Effect of X-ray Tube Parameters and Iodine Concentration On Image Quality and Radiation Dose in Cerebral Pediatric and Adult CT Angiography: a Phantom Study." Investigative Radiology, vol. 48, no. 4, 2013, pp. 192-9.
Papadakis AE, Perisinakis K, Raissaki M, et al. Effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral pediatric and adult CT angiography: a phantom study. Invest Radiol. 2013;48(4):192-9.
Papadakis, A. E., Perisinakis, K., Raissaki, M., & Damilakis, J. (2013). Effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral pediatric and adult CT angiography: a phantom study. Investigative Radiology, 48(4), 192-9. https://doi.org/10.1097/RLI.0b013e31827efc17
Papadakis AE, et al. Effect of X-ray Tube Parameters and Iodine Concentration On Image Quality and Radiation Dose in Cerebral Pediatric and Adult CT Angiography: a Phantom Study. Invest Radiol. 2013;48(4):192-9. PubMed PMID: 23344518.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral pediatric and adult CT angiography: a phantom study. AU - Papadakis,Antonios E, AU - Perisinakis,Kostas, AU - Raissaki,Maria, AU - Damilakis,John, PY - 2013/1/25/entrez PY - 2013/1/25/pubmed PY - 2013/8/24/medline SP - 192 EP - 9 JF - Investigative radiology JO - Invest Radiol VL - 48 IS - 4 N2 - OBJECTIVES: The aim of the present phantom study was to investigate the effect of x-ray tube parameters and iodine concentration on image quality and radiation dose in cerebral computed tomographic (CT) angiographic examinations of pediatric and adult individuals. MATERIALS AND METHODS: Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old children and the RANDO phantom that simulates the average adult individual were used. Cylindrical vessels were bored along the brain-equivalent plugs of each physical phantom. To simulate the brain vasculature, vessels of 0.6, 1, 2, and 3 mm in diameter were created. These vessels were filled with contrast medium (CM) solutions at different iodine concentrations, that is, 5.6, 4.2, 2.7, and 1.4 mg I/mL. The phantom heads were scanned at 120, 100, and 80 kV. The applied quality reference tube current-time product values ranged from a minimum of 45 to a maximum of 680. The CT acquisitions were performed on a 16-slice CT scanner using the automatic exposure control system. Image quality was evaluated on the basis of image noise and contrast-to-noise ratio (CNR) between the contrast-enhanced iodinated vessels and the unenhanced regions of interest. Dose reduction was calculated as the percentage difference of the CT dose index value at the quality reference tube current-time product and the CT dose index at the mean modulated tube current-time product. RESULTS: Image noise that was measured using the preset tube current-time product settings varied significantly among the different phantoms (P < 0.0001). Hounsfield unit number of iodinated vessels was linearly related to CM concentration (r² = 0.907) and vessel diameter (r² = 0.918). The Hounsfield unit number of iodinated vessels followed a decreasing trend from the neonate phantom to the adult phantom at all kilovoltage settings. For the same image noise level, a CNR improvement of up to 69% and a dose reduction of up to 61% may be achieved when CT acquisition is performed at 80 kV compared with 120 kV. For the same CNR, a reduction by 25% of the administered CM concentration may be achieved when CT acquisition is performed at 80 kV compared with 120 kV. CONCLUSIONS: In cerebral CT angiographic studies, appropriate adjustment of the preset tube current-time product settings is required to achieve the same image noise level among participants of different age. Cerebral CT angiography at 80 kV significantly improves CNR and significantly reduces radiation dose. Moreover, at 80 kV, a considerable reduction of the administered amount of the CM may be reached, thus reducing potential risks for contrast-induced nephropathy. SN - 1536-0210 UR - https://www.unboundmedicine.com/medline/citation/23344518/Effect_of_x_ray_tube_parameters_and_iodine_concentration_on_image_quality_and_radiation_dose_in_cerebral_pediatric_and_adult_CT_angiography:_a_phantom_study_ L2 - https://doi.org/10.1097/RLI.0b013e31827efc17 DB - PRIME DP - Unbound Medicine ER -