Chest CT Performed with Z-Axis Modulation: Scanning Protocol and Radiation Dose

Kalra, Mannudeep K.; Rizzo, Stefania; Maher, Michael M.; Halpern, Elkan F.; Toth, Thomas L.; Shepard, Jo Anne O.; Aquino, Suzanne L.

doi:10.1148/radiol.2371041227

Cited by 152 publications

(81 citation statements)

References 17 publications

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“…These findings are in agreement with previously published reports regarding CT of the chest, abdomen, and pelvis with use of ATCM. [6][7][8][9][10][11] In August 2001, the Society of Pediatric Radiology organized a multidisciplinary ALARA conference in that the consensus was a statistically significant, albeit small, individual risk for excess cancer in children from ionizing doses of radiation used in helical CT. On the basis of new and more extensive data, the Committee on the Biologic Effects of Ionizing Radiation VII supported a "linear-no-threshold" model, which states that the risk for cancer in humans proceeds in a linear fashion at lower doses without a "safe" threshold, and that even the smallest dose has the potential to cause a small increase in risk to humans. 13 Although reduction in radiation dose is an important exercise, maintaining high quality of a diagnostic imaging study is also essential to provide an accurate and definitive diagnosis.…”

Section: Discussionmentioning

confidence: 99%

“…[6][7][8][9][10][11] To our knowledge, there is no published study evaluating its use in imaging of the head and neck, and no publication addresses radiation dose and image quality with 64-section multidetector row CT (MDCT). Thus, the purposes of this study were to assess whether the ATCM technique reduces radiation dose compared with the fixedtube current technique without compromising image quality in a 64-section MDCT of the neck.…”

mentioning

confidence: 99%

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Balancing Radiation Dose and Image Quality: Clinical Applications of Neck Volume CT

Russell¹,

Fink²,

Rebeles³

et al. 2008

AJNR Am J Neuroradiol

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Balancing Radiation Dose and Image Quality: Clinical Applications of Neck Volume CT

Russell¹,

Fink²,

Rebeles³

et al. 2008

AJNR Am J Neuroradiol

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“…Also, despite the drastic advancement in the latest CT systems with advanced strategies in reducing the overall radiation dose to the patient, making the implementation of bismuth shields less frequent (Kalra et al, 2004(Kalra et al, , 2005Lee et al, 2010), the efficacy of reducing the eye lens dose during CT brain imaging by a bismuth shield and organ-based tube current modulation was similar (Wang et al, 2012).…”

Section: Current Strategies To Reduce the Eye Lens Dose During Ct Bramentioning

confidence: 99%

Reducing the radiation dose to the eye lens region during CT brain examination: the potential beneficial effect of the combined use of bolus and a bismuth shield

et al. 2015

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-Objective:Computed Tomography (CT) is the leading contributor to medical exposure to ionizing radiation. Although the use of CT brain scans for patients with head injuries and convulsions has shown a tremendous growth, it has raised substantial concerns in the general public because of the risk of radiation-induced cataracts: the current available strategies to reduce the radiation dose to the eye lens region are limited. Therefore, the present research project was initiated with the aim of evaluating the potential benefit of the combined use of bolus and a bismuth shield on reducing the radiation dose to the eye lens region during CT brain examination. Materials and methods: We conducted a series of phantom studies to measure the entrance surface dose (ESD) that is delivered to the eye lens region during CT brain examination under the effect of different scanning and shielding setups. Results: Our results indicated, during CT brain examination: (1) a drastic reduction of 92.5% in the ESD to the eye lens region was found when the CT gantry was tilted from 0• (overall ESD = 30.7 mGy) to 30• cranially (overall ESD = 2.4 mGy), and (2) when the CT gantry was positioned at 0• (the common practice in the clinical setting), the setups with the application of a) a bismuth shield, b) a bismuth shield with a face shield (air gap), c) a bismuth shield with bolus, and d) a bismuth shield with bolus and an air gap can result in an acceptable level of image quality with a smaller overall ESD delivered to the eye lens region (overall ESD = 23.2 mGy, 24 mGy, 21 mGy and 19.9 mGy, respectively) than the setup without the bismuth shield applied (overall ESD = 30.7 mGy). Conclusion: When the primary beam scanning through the eye lens region is unavoidable during CT brain examination, the combined use of a bismuth shield with bolus and a face shield is an easyto-use and inexpensive shielding setup to reduce the radiation dose delivered to the eye lens region while maintaining the correct CT number and a low degree of image noise in the resultant image.

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“…Dose modulation can be performed in the z-axis where tube current changes along the length of the patient, in the xy-plane (angular modification), or can be a combination of the 2 (xyz-dose modulation). Recent studies demonstrated that dose modulation is capable of providing a reduction in radiation dose without significant image compromise, [16][17][18][19][20] including for neuroradiology CT protocols, where up to 60% dose reduction was achieved for noncontrast CT of the brain in adult and pediatric patients; for CT studies of the cervical spine; and for CTA studies. 21 Implementation of dose modulation requires a team effort between radiologists, technicians, and physicists, who have to select a preset noise index (NI) that describes the level of noise acceptable to the radiologist for a given CT examination.…”

Section: Physics Reviewmentioning

confidence: 99%

Radiation Dose-Reduction Strategies for Neuroradiology CT Protocols

Smith¹,

Dillon²,

Gould³

et al. 2007

American Journal of Neuroradiology

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SUMMARY:Within the past 2 decades, the number of CT examinations performed has increased almost 10-fold. This is in large part due to advances in multidetector-row CT technology, which now allows faster image acquisition and improved isotropic imaging. The increased use, along with multidetector technique, has led to a significantly increased radiation dose to the patient from CT studies. This places increased responsibility on the radiologist to ensure that CT examinations are indicated and that the "as low as reasonably achievable" concept is adhered to. Neuroradiologists are familiar with factors that affect patient dose such as pitch, milliamperes, kilovolt peak (kVp), collimation, but with increasing attention being given to dose reduction, they are looking for additional ways to further reduce the radiation associated with their CT protocols. In response to increasing concern, CT manufacturers have developed dose-reduction tools, such as dose modulation, in which the tube current is adjusted along with the CT acquisition, according to patient's attenuation. This review will describe the available techniques for reducing dose associated with neuroradiologic CT imaging protocols.T he increase in the number of CT studies in the United States and Europe 1,2 that followed the introduction of multidetector-row technology has led to a significant increase in the radiation dose related to CT scanning.3-6 CT scanning comprises approximately 15% of radiologic examinations but represents the largest single source of medical radiation exposure, accounting for up to 70% of the radiation dose to patients. 7 Patients are becoming more aware of the radiation dose related to CT scanning due to increasing coverage in the lay press. 8 The radiation risk to children is of particular concern; the estimated lifetime cancer risk for a 1-year-old child from the radiation exposure of a head CT is 0.07%. 9The potential health risks associated with radiation have placed increasing pressure on the radiology community to ensure that CT imaging protocols are optimized for diagnostic image quality at the lowest radiation dose possible ("as low as reasonably achievable"). Because the latest generation of CT scanners automatically records the CT dose for each study and archives this as part of the patient's permanent medical record, exaggerated delays in implementing dose-reduction strategies may also have medical-legal implications. The purpose of this review is to discuss available methods to achieve dose reduction for neuroradiology CT protocols while preserving the diagnostic quality of imaging studies. CT-Associated Radiation-Dose MeasurementIn 2001, in response to the growing concern over CT-associated radiation dose, the US Food and Drug Administration published guidelines to address this issue, especially in pediatric patients and in the small-adult population. These guidelines give recommendations on how to optimize CT protocols and encourage the elimination of inappropriate referrals for CT as well as the reduction of the numbe...

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Chest CT Performed with Z-Axis Modulation: Scanning Protocol and Radiation Dose

Cited by 152 publications

References 17 publications

Balancing Radiation Dose and Image Quality: Clinical Applications of Neck Volume CT

Balancing Radiation Dose and Image Quality: Clinical Applications of Neck Volume CT

Reducing the radiation dose to the eye lens region during CT brain examination: the potential beneficial effect of the combined use of bolus and a bismuth shield

Radiation Dose-Reduction Strategies for Neuroradiology CT Protocols

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