期刊
MEDICAL PHYSICS
卷 32, 期 11, 页码 3395-3408出版社
WILEY
DOI: 10.1118/1.2064767
关键词
mammography; dual energy; calcifications; digital mammography
资金
- NCI NIH HHS [CA 104759] Funding Source: Medline
- NIBIB NIH HHS [EB000117] Funding Source: Medline
Mammographic images of small calcifications, which are often the earliest signs of breast cancer, can be obscured by overlapping fibroglandular tissue. We have developed and implemented a dual-energy digital mammography (DEDM) technique for calcification imaging under full-field imaging conditions using a commercially available aSi:H/Csl:Tl flat-panel based digital mammography system. The low- and high-energy images were combined using a nonlinear mapping function to cancel the tissue structures and generate the dual-energy (DE) calcification images. The total entrance-skin exposure and mean-glandular dose from the low- and high-energy images were constrained so that they were similar to screening-examination levels. To evaluate the DE calcification image, we designed a phantom using calcium carbonate crystals to simulate calcifications of various sizes (212-425 mu m) overlaid with breast-tissue-equivalent material 5 cm thick with a continuously varying glandular-tissue ratio from 0% to 100%. We report on the effects of scatter radiation and nonuniformity in x-ray intensity and detector response on the DE calcification images. The nonuniformity was corrected by normalizing the low- and high-energy images with full-field reference images. Correction of scatter in the low- and high-energy images significantly reduced the background signal in the DE calcification image. Under the current implementation of DEDM, utilizing the mammography system and dose level tested, calcifications in the 300-355 mu m size range were clearly visible in DE calcification images. Calcification threshold sizes decreased to the 250-280 mu m size range when the visibility criteria were lowered to barely visible. Calcifications smaller than similar to 250 mu m were usually not visible in most cases. The visibility of calcifications with our DEDM imaging technique was limited by quantum noise, not system noise. 0 2005 American Association of Physicists in Medicine.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据