Korean J Radiol.  2012 Feb;13(1):1-11. 10.3348/kjr.2012.13.1.1.

CT Radiation Dose Optimization and Estimation: an Update for Radiologists

• Goo HW

• KMID: 1058787
• DOI: http://doi.org/10.3348/kjr.2012.13.1.1

Abstract

In keeping with the increasing utilization of CT examinations, the greater concern about radiation hazards from examinations has been addressed. In this regard, CT radiation dose optimization has been given a great deal of attention by radiologists, referring physicians, technologists, and physicists. Dose-saving strategies are continuously evolving in terms of imaging techniques as well as dose management. Consequently, regular updates of this issue are necessary especially for radiologists who play a pivotal role in this activity. This review article will provide an update on how we can optimize CT dose in order to maximize the benefit-to-risk ratio of this clinically useful diagnostic imaging method.

Keyword

CT radiation dose; Low dose CT; Radiation dose reduction; MDCT

MeSH Terms

Body Size
Cardiac-Gated Imaging Techniques/methods
Humans
*Radiation Dosage
Radiographic Image Interpretation, Computer-Assisted
Radiometry
Risk Assessment
Tomography, X-Ray Computed/*methods

Figure

• 

  Fig. 1 Axial contrast-enhanced chest CT images using dual-source CT system with different energy levels (A: 80 kVp, B: mixed with composition ratio of 0.4, C: 140 kVp with tin filter). Degree of contrast enhancement is higher at 80 kVp (A) than at 140 kVp with tin filter (C) as result of different X-ray linear attenuation coefficients between iodine and water. Images (A, C) reconstructed from single X-ray source appear to be noisier than mixed image (B) because of difference in radiation dose by factor of approximately two.

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  Fig. 2 Diagram illustrating overbeaming, overranging, and adaptive section collimation technology during spiral scanning.

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  Fig. 3 Volume-rendered cardiac CT images seen from feet. Compared with image using standard reconstruction algorithm (A), image using conventional noise-reducing reconstruction filter (B) shows degraded anatomic details of small peripheral pulmonary vessels.

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  Fig. 4 Graph showing difference in radiation dose between peak dose and CT dose index (modified from reference [60]). Dose from CT scanning without table increment is overestimated by factor of two or more with CT dose index (CTDI) values in comparison with point dose values.

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