J Breast Cancer.  2013 Mar;16(1):90-96.

Dose Reduction in Automatic Optimization Parameter of Full Field Digital Mammography: Breast Phantom Study

• Ko MS
• Kim HH
• Cha JH
• Shin HJ
• Kim JH
• Kim MJ

Abstract

PURPOSE
We evaluated the impact of three automatic optimization of parameters (AOP) modes of digital mammography on the dose and image quality.
METHODS
Computerized Imaging Reference Systems phantoms were used. A total of 12 phantoms with different thickness and glandularity were imaged. We analyzed the average glandular dose (AGD) and entrance surface exposure (ESE) of 12 phantoms imaged by digital mammography in three modes of AOP; namely standard mode (STD), contrast mode (CNT), and dose mode (DOSE). Moreover, exposure factors including kVp, mAs, and target/filter combination were evaluated. To evaluate the quality of the obtained digital image, two radiologists independently counted the objects of the phantoms.
RESULTS
According to the AOP modes, the score of masses and specks was sorted as CNT>STD=DOSE. There was no difference in the score of fiber among the three modes. The score of image preference was sorted as CNT>STD>DOSE. The AGD, ESE, and mAs were sorted as CNT>STD>DOSE. The kVp was sorted as CNT=STD>DOSE. The score of all test objects in the phantom image was on a downtrend with increasing breast thickness. The score of masses was different among the three groups; 20-21%>30%>50% glandularity. The score of specks was sorted as 20-21%=30%>50% glandularity. The score of fibers was sorted as 30%>20-21%=50% glandularity. The score of image preference was not different among the three glandularity groups. The AGD, ESE, kVp, and mAs were correlated with breast thickness, but not correlated with glandularity.
CONCLUSION
The DOSE mode offers significant improvement (19.1-50%) in dose over the other two modes over a range of breast thickness and breast glandularity with acceptable image quality. Owning knowledge of the three AOP modes may reduce unnecessary radiation exposure by utilizing the proper mode according to its purpose.

Keyword

Breast; Imaging phantom; Mammography; Radiation dosage

MeSH Terms

Breast
Mammography
Phantoms, Imaging
Radiation Dosage

Figure

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  Figure 1 Schematic diagram of a Computerized Imaging Reference Systems (CIRS) phantom. The phantom breast detail component consists of 12 CaCO3 specks groups of different sizes, 7 hemispheric masses of different diameters, and 5 nylon fibers of different diameters.

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  Figure 2 The image quality of all types among the three modes. Image quality is the number of fibers, specks, masses visualized, or image preference. STD=standard mode; CNT=contrast mode; DOSE=dose mode; M=mass; F=fiber; S=specks; P=image perference.

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  Figure 3 Relationship between image quality and breast thickness. STD=standard mode; CNT=contrast mode; DOSE=dose mode; M=mass; F=fiber; S=specks; P=image perference.

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  Figure 4 (A-D) The relationship between the image quality over a range of breast thickness and glandularity according to the automatic optimization of parameters (AOP) modes. Image quality is the dose-normalized scores of fibers, specks, masses visualized, or image preferences (lesion scores/average glandular dose [AGD]). STD=standard mode; CNT=contrast mode; DOSE=dose mode.

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