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. 2009 Oct;1(1):65-84.
doi: 10.2217/iim.09.5.

Radiation dose reduction in computed tomography: techniques and future perspective

Lifeng Yu  1 , Xin Liu, Shuai Leng, James M Kofler, Juan C Ramirez-Giraldo, Mingliang Qu, Jodie Christner, Joel G Fletcher, Cynthia H McCollough
Affiliations

Radiation dose reduction in computed tomography: techniques and future perspective

Lifeng Yu et al. Imaging Med. 2009 Oct.

Abstract

Despite universal consensus that computed tomography (CT) overwhelmingly benefits patients when used for appropriate indications, concerns have been raised regarding the potential risk of cancer induction from CT due to the exponentially increased use of CT in medicine. Keeping radiation dose as low as reasonably achievable, consistent with the diagnostic task, remains the most important strategy for decreasing this potential risk. This article summarizes the general technical strategies that are commonly used for radiation dose management in CT. Dose-management strategies for pediatric CT, cardiac CT, dual-energy CT, CT perfusion and interventional CT are specifically discussed, and future perspectives on CT dose reduction are presented.

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Conflict of interest statement

Financial & competing interests disclosure

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Figures

Figure 1
Figure 1. An example of automatic exposure control in a helical scan
The tube current was automatically modulated according to the attenuation level at each x-ray projection view. Owing to the continuous translation of patient table through the computed tomography gantry in the helical scan, each table position corresponds to a projection view. When the attenuation level at a projection view is large, the tube current increases. When the attenuation level is small, the tube current decreases. The goal of the tube current modulation is to automatically maintain the same noise level or image quality irrespective of the attenuation level or patient size. The targeted noise level or image quality is predefined through noise index, quality reference mAs or other metrics, varying with the different implementations of automatic exposure control.
Figure 2
Figure 2. Patient scanned with a protocol at 120 kV (A) and 100 kV (B)
Note the improved contrast-to-noise ratio and visualization of mural stratification of the 100 kV image, despite a 23% radiation dose reduction. CTDIvol: Volume computed tomography dose index.
Figure 3
Figure 3. An example of computed tomography simulation for evaluating the possible dose reduction
(A) Liver computed tomography image at arterial phase with original dose level and (B–D) three images with lower dose levels obtained from computer simulation.
Figure 4
Figure 4. Renal perfusion computed tomography images with (A) routine dose level (80 kV, 160 mAs), (B) one-tenth of the dose level (80 kV, 16 mAs) and (C) highly constrained back projection local reconstruction processed with one-tenth of the dose level
Mean and standard deviation of computed tomography numbers at a selected region of interest (arrow) in the back muscles are also shown in the figure. The highlighted renal contour is the region of renal cortex. Reprinted with permission from [145].
See this image and copyright information in PMC

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