Understanding CT Dose Display

The Russell H. Morgan Department of Radiology and Radiological Science, John Hopkins University School of Medicine, Baltimore, Maryland.
Journal of the American College of Radiology: JACR (Impact Factor: 2.84). 09/2012; 9(9):669-71. DOI: 10.1016/j.jacr.2012.06.003
Source: PubMed
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    ABSTRACT: Purpose: The aims of this study were to measure the effectiveness of a multidisciplinary CT dose optimization committee and estimate its costs and to describe a radiation stewardship quality improvement initiative in one CT department at a medium-sized community hospital system that used a participatory design committee methodology. Methods: A CT dose optimization committee was conceived, funded, and formed, consisting of the following stakeholders: radiologists, technologists, consultant medical physicists, and an administrator. Volume CT dose index (CTDIvol) and repeat rate were monitored for 1 month, for one scan type, during which iterative protocol adjustments were made through committee interaction. Effects on repeat rate and CTDIvol were quantified and benchmarked against national diagnostic reference levels after retrospective medical record review of 100 consecutive patients before and after the intervention. Labor hours were reported and wage resources estimated. Results: Over 3 months, the committee met in person twice and exchanged 128 e-mails in establishing a process for protocol improvement and measurement of success. Repeat rate was reduced from 13% (13 of 100) to 0% (0 of 100). Scans meeting the ACR reference level for CTDIvol (75 mGy) improved by 34% (38 of 100 before, 51 of 100 after; Fisher's exact 2-tailed P = .09), and those meeting ACR pass/fail criterion (80 mGy) improved by 29% (58 of 100 before, 75 of 100 after; Fisher's exact 2-tailed P = .01). Committee evolution and work, and protocol development and implementation, required 57 person-hours, at an estimated labor cost of $12,488. Conclusions: An efficient process was established as a proof of concept for the use of a multidisciplinary committee to reduce patient radiation dose, repeat rate, and variability in image quality. The committee and process ultimately improved the quality of patient care, fostered a culture of safety and ongoing quality improvement, and calculated costs for such an endeavor.
    No preview · Article · Mar 2013 · Journal of the American College of Radiology: JACR
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    ABSTRACT: Risks associated to ionising radiation from medical imaging techniques have focused the attention of the medical society and general population. This risk is aimed to determine the probability that a tumour is induced as a result of a computed tomography (CT) examination since it makes nowadays the biggest contribution to the collective dose. Several models of cancer induction have been reported in the literature, with diametrically different implications. This article reviews those models, focusing on the ones used by the scientific community to estimate CT detriments. Current estimates of the probability that a CT examination induces cancer are reported, highlighting its low magnitude (near the background level) and large sources of uncertainty. From this objective review, it is concluded that epidemiological data with more accurate dosimetric estimates are needed. Prediction of the number of tumours that will be induced in population exposed to ionising radiation should be avoided or, if given, it should be accompanied by a realistic evaluation of its uncertainty and of the advantages of CTs. Otherwise they may have a negative impact in both the medical community and the patients. Reducing doses even more is not justified if that compromises clinical image quality in a necessary investigation. Key Points • Predictions of radiation-induced cancer should be discussed alongside benefits of imaging. • Estimates of induced cancers have noticeable uncertainties that should always be highlighted. • There is controversy about the acceptance of the linear no-threshold model. • Estimated extra risks of cancer are close to the background level. • Patients should not be alarmed by potential cancer induction by CT examinations.
    No preview · Article · Nov 2013 · European Radiology
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    ABSTRACT: Improving patient safety by minimizing CT radiation dose, while maintaining diagnostic image quality, has become an important skill in diagnostic radiology. The aim of this study was to examine the value of an educational workshop for optimizing CT protocols in an academic department, and to assess its impact on resident education. The CT Dose Reduction Workshop met monthly for 1 year, to teach and implement dose reduction strategies. Changes were made to CT protocols through group consensus while participants kept up to date with current literature. A survey was sent to 48 radiology residents and 32 attending radiologists in the department, including both participants and nonparticipants, after completion of the workshop, to assess its utility. The survey used a 5-point Likert-type scale. Average doses for a specific CT protocol before and after the workshop were compared. About 80% of respondents agreed or strongly agreed that the workshop was essential. Workshop participants expressed greater confidence in their knowledge of dose reduction techniques, with a mean score of 3.74 (95% confidence interval, 3.35-4.13), compared with nonparticipants, who had a mean score of 3.00 (95% confidence interval, 2.64-3.36) (P < .01). Dose reductions were established across numerous CT protocols. For instance, the average total dose-length product in renal mass protocol CT examinations decreased by 54% (P < .0001). A CT dose reduction workshop increases participants' confidence in knowledge of dose reduction techniques, fosters a culture of safety and quality improvement in the department, and reduces radiation dose to patients. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.
    No preview · Conference Paper · Jan 2014
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