Dose reduction in CT using bismuth shielding: measurements and Monte Carlo simulations

Chang, Kyung Hwan; Lee, Wonho; Choo, Dong Myung; Lee, Choon Sik; Kim, You-Hyun

doi:10.1093/rpd/ncp278

Cited by 30 publications

(12 citation statements)

References 12 publications

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“…11 Chang et al found artifacts to be minimal if the distance between bismuth shielding and organs (breast, thyroid, or eye) was greater than 1 cm. 12 In a series of 50 thoracic scans, Yilmaz et al observed no differences in image quality between shielded and unshielded lungs. 13 However, none of these studies quantitatively assessed image noise in organs being imaged.…”

Section: Discussionmentioning

confidence: 95%

Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography

Einstein

Elliston

Groves

et al. 2012

Journal of Nuclear Cardiology

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Background Coronary computed tomographic angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding offers the potential to significantly reduce dose to the breasts and nearby organs, but the magnitude of this reduction and its impact on image quality and radiation dose have not been evaluated. Methods Radiation doses from CCTA to critical organs were determined using metal-oxide-semiconductor field-effect transistors positioned in a customized anthropomorphic whole-body dosimetry verification phantom. Image noise and signal were measured in regions of interest (ROIs) including the coronary arteries. Results With bismuth shielding, breast radiation dose was reduced 46–57% depending on breast size and scanning technique, with more moderate dose reduction to the heart, lungs, and esophagus. However, shielding significantly decreased image signal (by 14.6 HU) and contrast (by 28.4 HU), modestly but significantly increased image noise in ROIs in locations of coronary arteries, and decreased contrast-to-noise ratio by 20.9%.. Conclusions While bismuth breast shielding can significantly decrease radiation dose to critical organs, it is associated with an increase in image noise, decrease in contrast-to-noise, and changes tissue attenuation characteristics in the location of the coronary arteries.

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Section: Discussionmentioning

confidence: 95%

Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography

Einstein

Elliston

Groves

et al. 2012

Journal of Nuclear Cardiology

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“…7 However, its use was replaced by bismuth shielding, which provided improved opportunities to reduce dose to superficial organs within the field of view. 8 While various studies have proven that lead and bismuth provide equivalent dose reductions [9][10][11] ; bismuth shields are designed for specific superficial organs and have the added benefit of being lightweight and easy to manoeuvre. 8 Recently, the use of bismuth shields has sparked debate in relation to issues caused during scans.…”

Section: Introductionmentioning

confidence: 99%

The Current Use and Effectiveness of Bismuth Shielding in Computed Tomography: A Systematic Review

Lawrence¹,

Seeram²

2017

Radiol Open J

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CitationThe increased use of computed tomography (CT) has raised concerns regarding the radiation dose received by radiosensitive organs. It is important that practical and reliable dose reduction strategies are implemented to reduce patient radiation exposure. Aims: The purpose of this article is to evaluate the current clinical use and effectiveness of bismuth shielding as a dose reduction technique and assess its impact on image quality, in an attempt to develop a recommendation for dose reduction in CT. Methods: A systematic review of current literature was conducted using the PubMed and Scopus databases. A total of 50 relevant articles were thoroughly assessed and evaluated.Results: This review found that whilst bismuth shielding proves to provide significant dose reductions to radiosensitive organs, numerous concerns exist including wasted radiation, reduced image quality and unpredictable results when combined with AEC. Alternative methods such as tube current modulation and iterative reconstruction algorithms can provide equivalent dose savings at superior image quality, without the limitations of bismuth shields. Conclusion: Until these alternative methods become available in all departments, bismuth shielding remains a viable dose reduction strategy.

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“…10 A thyroid collar was found to reduce radiation doses significantly during CT scanning of the head. [11][12][13][14] However, until now there have been no studies published to evaluate the radioprotective effects of thyroid collars during CBCT scanning. The aim of this study was to evaluate the radiation dose of CBCT when applying thyroid collars.…”

Section: Introductionmentioning

confidence: 99%

Dose reduction of cone beam CT scanning for the entire oral and maxillofacial regions with thyroid collars

Li²,

Sanderink³

et al. 2012

Dentomaxillofacial Radiology

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Objective: The aim of this study was to evaluate the influence of thyroid collars on radiation dose during cone beam CT (CBCT) scanning. Methods: Average tissue-absorbed dose for a NewTom 9000 CBCT scanner (Quantitative Radiology, Verona, Italy) was measured using thermoluminescent dosemeter chips in a phantom. The scans were carried out with and without thyroid collars. Effective organ dose and total effective dose were derived using International Commission on Radiological Protection 2007 recommendations. Results: The effective organ doses for the thyroid gland and oesophagus were 31.0 mSv and 2.4 mSv, respectively, during CBCT scanning without a collar around the neck. When the thyroid collars were used loosely around the neck, no effective organ dose reduction was observed. When one thyroid collar was used tightly on the front of the neck, the effective organ dose for the thyroid gland and oesophagus were reduced to 15.9 mSv (48.7% reduction) and 1.4 mSv (41.7% reduction), respectively. Similar organ dose reduction (46.5% and 41.7%) was achieved when CBCT scanning was performed with two collars tightly on the front and back of the neck. However, the differences to the total effective dose were not significant among the scans with and without collars around the neck (p 5 0.775). Conclusions: Thyroid collars can effectively reduce the radiation dose to the thyroid and oesophagus if used appropriately.

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Dose reduction in CT using bismuth shielding: measurements and Monte Carlo simulations

Cited by 30 publications

References 12 publications

Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography

Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography

The Current Use and Effectiveness of Bismuth Shielding in Computed Tomography: A Systematic Review

Dose reduction of cone beam CT scanning for the entire oral and maxillofacial regions with thyroid collars

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