scholarly journals Application of Different methods for Reducing Radiation Dose to Breast during MDCT

2018 ◽  
Author(s):  
M Keshtkar ◽  
V Saba ◽  
M A Mosleh-Shirazi
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Income ◽  
Low Income Countries ◽  
Radiological Protection ◽  
Reconstruction Algorithms ◽  
Radiation Induced Cancer ◽  
Bismuth Shielding ◽  
Ct Scanners ◽  
Radiosensitive Organs

The increased use of computed tomography (CT) and its high radiation dose have led to great concerns about its potential for radiation induced cancer risks. Breast is a radiosensitive tissue based on tissue weighting factors assigned by the International Commission on Radiological Protection (ICRP). Moreover, the dose is maximal on the surface of the patient. Therefore, strategies should be taken to reduce radiation dose to the breast. The aim of this review is to introduce methods used for reducing radiation dose to breast in thoracic CT and review related performed studies. The literature indicates that bismuth shielding increases image noise and CT numbers as well as introducing streak artifacts. Tube current modulation (TCM) technique and iterative reconstruction algorithms can provide some levels of dose reduction to radiosensitive organs and superior image quality without the disadvantages of bismuth shielding. However, they are not available on all CT scanners, especially in low-income countries. Such centers may have to continue using bismuth shields to reduce the dose until these superior techniques become available at lower costs in all CT scanners. Furthermore, design and manufacture of new shields with the lower impact on image quality are desirable.

Reducing CT radiation dose with iterative reconstruction algorithms: The influence of scan and reconstruction parameters on image quality and CTDIvol

2014 ◽  
Vol 83 (9) ◽  
pp. 1645-1654 ◽  
Author(s):  
Thorsten Klink ◽  
Verena Obmann ◽  
Johannes Heverhagen ◽  
Alexander Stork ◽  
Gerhard Adam ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Reconstruction Algorithms ◽  
Ct Radiation

Acquisition time, radiation dose, subjective and objective image quality of dual-source CT scanners in acute pulmonary embolism: a comparative study

2020 ◽  
Vol 30 (5) ◽  
pp. 2712-2721 ◽  
Author(s):  
Waleed Abdellatif ◽  
Eric Esslinger ◽  
Kevin Kobes ◽  
Amanda Wong ◽  
Jennifer Powell ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Comparative Study ◽  
Acute Pulmonary Embolism ◽  
Acquisition Time ◽  
Dual Source Ct ◽  
Dual Source ◽  
Ct Scanners

Radiation dose and image quality inK-edge subtraction computed tomography of lungin vivo

2014 ◽  
Vol 21 (6) ◽  
pp. 1305-1313 ◽  
Author(s):  
S. Strengell ◽  
J. Keyriläinen ◽  
P. Suortti ◽  
S. Bayat ◽  
A. R. A. Sovijärvi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Signal To Noise Ratio ◽  
Regional Distribution ◽  
Lung Ventilation ◽  
Structural Features ◽  
Reconstruction Algorithms ◽  
Human Thorax

K-edge subtraction computed tomography (KES-CT) allows simultaneous imaging of both structural features and regional distribution of contrast elements inside an organ. Using this technique, regional lung ventilation and blood volume distributions can be measured experimentallyin vivo. In order for this imaging technology to be applicable in humans, it is crucial to minimize exposure to ionizing radiation with little compromise in image quality. The goal of this study was to assess the changes in signal-to-noise ratio (SNR) of KES-CT lung images as a function of radiation dose. The experiments were performed in anesthetized and ventilated rabbits using inhaled xenon gas in O2at two concentrations: 20% and 70%. Radiation dose, defined as air kerma (Ka), was measured free-in-air and in a 16 cm polymethyl methacrylate phantom with a cylindrical ionization chamber. The dose free-in-air was varied from 2.7 mGy to 8.0 Gy. SNR in the images of xenon in air spaces was above the Rose criterion (SNR > 5) whenKawas over 400 mGy with 20% xenon, and over 40 mGy with 70% xenon. Although in human thorax attenuation is higher, based on these findings it is estimated that, by optimizing the imaging sequence and reconstruction algorithms, the radiation dose could be further reduced to clinically acceptable levels.

Image quality of low-radiation dose left atrial CT using filtered back projection and an iterative reconstruction algorithm: intra-individual comparison in unselected patients undergoing pulmonary vein isolation

2017 ◽  
Vol 59 (2) ◽  
pp. 161-169
Author(s):  
Ute Lina Fahlenkamp ◽  
Ivan Diaz Ramirez ◽  
Moritz Wagner ◽  
Carsten Schwenke ◽  
Alexander Huppertz ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dual Source Ct ◽  
Back Projection ◽  
Reconstruction Algorithms ◽  
Effective Radiation Dose ◽  
Subjective Image Quality ◽  
Low Radiation Dose ◽  
Dual Source ◽  
Effective Radiation

Background Computed tomography (CT) of the left atrium (LA) is performed prior to pulmonary vein isolation (PVI) to improve success of circumferential ablation for atrial fibrillation. The ablation procedure itself exposes patients to substantial radiation doses, therefore radiation dose reduction in pre-ablational imaging is of concern. Purpose To assess and compare diagnostic performance of low-radiation dose preprocedural CT in patients scheduled for PVI using two types of reconstruction algorithms. Material and Methods Forty-six patients (61 ± 10 years) scheduled for PVI were enrolled in this study irrespective of body-mass-index or cardiac rhythm at examination. An electrocardiographically triggered dual-source CT scan was performed. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. Images were integrated into an electroanatomic mapping (EAM) system. Subjective image quality was scored independently by two readers on a five-point scale for both reconstruction algorithms (1 = excellent to 5 = non-diagnostic). Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective radiation dose were calculated. Results Data acquisition and EAM integration were successful in all patients. Median image quality score was 1 for both FBP (quartiles = 1, 1.62; range = 1–3) and IR (quartiles = 1, 1.5; range = 1–3). Mean SNR was 7.61 ± 2.14 for FBP and 9.02 ± 2.69 for IR. Mean CNR was 5.92 ± 1.80 for FBP and 6.95 ± 2.29 for IR. Mean effective radiation dose was 0.3 ± 0.1 mSv. Conclusion At a radiation dose of 0.3 ± 0.1 mSv, high-pitch dual-source CT yields LA images of consistently high quality using both FBP and IR. IR raises SNR and CNR without significantly improving subjective image quality.

Radiation dose and image quality of computed tomography of the supra-aortic arteries: A comparison between single-source and dual-source CT Scanners

2018 ◽  
Vol 45 (2) ◽  
pp. 136-141 ◽  
Author(s):  
Luca Saba ◽  
Michele di Martino ◽  
Paolo Siotto ◽  
Michele Anzidei ◽  
Giovanni Maria Argiolas ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Dual Source Ct ◽  
Single Source ◽  
Dual Source ◽  
Ct Scanners

scholarly journals Diagnostic reference levels in low- and middle-income countries: early “ALARAm” bells?

2016 ◽  
Vol 58 (4) ◽  
pp. 442-448 ◽  
Author(s):  
Steven Meyer ◽  
Willem A Groenewald ◽  
Richard D Pitcher
Keyword(s):  
Quality Assurance ◽  
Low Income ◽  
Low Income Countries ◽  
Dose Optimization ◽  
Radiological Protection ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Middle Income ◽  
Middle Income Countries ◽  
Low And Middle Income

Background In 1996 the International Commission on Radiological Protection (ICRP) introduced diagnostic reference levels (DRLs) as a quality assurance tool for radiation dose optimization. While many countries have published DRLs, available data are largely from high-income countries. There is arguably a greater need for DRLs in low- and middle-income-countries (LMICs), where imaging equipment may be older and trained imaging technicians are scarce. To date, there has been no critical analysis of the published work on DRLs in LMICs. Such work is important to evaluate data deficiencies and stimulate future quality assurance initiatives. Purpose To review the published work on DRLs in LMICs and to critically analyze the comprehensiveness of available data. Material and Methods Medline, Scopus, and Web of Science database searches were conducted for English-language articles published between 1996 and 2015 documenting DRLs for diagnostic imaging in LMICs. Retrieved articles were analyzed and classified by geographical region, country of origin, contributing author, year of publication, imaging modality, body part, and patient age. Results Fifty-three articles reported DRLs for 28 of 135 LMICs (21%), reflecting data from 26/104 (25%) middle-income countries and 2/31 (6%) low-income countries. General radiography (n = 26, 49%) and computerized tomography (n = 17, 32%) data were most commonly reported. Pediatric DRLs (n = 14, 26%) constituted approximately one-quarter of published work. Conclusion Published DRL data are deficient in the majority of LMICs, with the paucity most striking in low-income countries. DRL initiatives are required in LMICs to enhance dose optimization.

scholarly journals Bismuth Pelvic X-Ray Shielding Reduces Radiation Dose Exposure in Pediatric Radiography

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Bow Wang ◽  
Chien-Yi Ting ◽  
Cheng-Shih Lai ◽  
Yi-Shan Tsai
Keyword(s):  
Radiation Dose ◽  
Background Radiation ◽  
Radiation Doses ◽  
X Ray ◽  
Radiation Dose Exposure ◽  
Bismuth Shielding ◽  
Pediatric Radiography ◽  
Pelvic Radiography ◽  
Radiosensitive Organs ◽  
Pediatric Orthopedic

Background. Radiation using conventional X-ray is associated with exposure of radiosensitive organs and typically requires the use of protection. This study is aimed at evaluating the use of bismuth shielding for radiation protection in pediatric pelvic radiography. The effects of the anteroposterior and lateral bismuth shielding were verified by direct measurements at the anatomical position of the gonads. Methods. Radiation doses were measured using optically stimulated luminescence dosimeters (OSLD) and CIRS ATOM Dosimetry Verification Phantoms. Gonad radiographs were acquired using different shields of varying material (lead, bismuth) and thickness and were compared with radiographs obtained without shielding to examine the effects on image quality and optimal reduction of radiation dose. All images were evaluated separately by three pediatric orthopedic practitioners. Results. Results showed that conventional lead gonadal shielding reduces radiation doses by 67.45%, whereas dose reduction using one layer of bismuth shielding is 76.38%. The use of two layers of bismuth shielding reduces the dose by 84.01%. Using three and four layers of bismuth shielding reduces dose by 97.33% and 99.34%, respectively. Progressively lower radiation doses can be achieved by increasing the number of bismuth layers. Images obtained using both one and two layers of bismuth shielding provided adequate diagnostic information, but those obtained using three or four layers of bismuth shielding were inadequate for diagnosis. Conclusions. Bismuth shielding reduces radiation dose exposure providing appropriate protection for children undergoing pelvic radiography. The bismuth shielding material is lighter than lead, making pediatric patients more comfortable and less apt to move, thereby avoiding repeat radiography.

Image quality in coronary computed tomography angiography: influence of adaptive statistical iterative reconstruction at various radiation dose levels

2018 ◽  
Vol 59 (10) ◽  
pp. 1194-1202 ◽  
Author(s):  
Helle Precht ◽  
Oke Gerke ◽  
Jesper Thygesen ◽  
Kenneth Egstrup ◽  
Søren Auscher ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Quality Criteria ◽  
Left Ventricular ◽  
Reconstruction Algorithms ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Low Contrast ◽  
Statistical Iterative Reconstruction

Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32–0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02–1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01–1.12; P = 0.034) compared to FBP. Conclusion ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.

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