A scatter correction method for contrast-enhanced dual-energy digital breast tomosynthesis

Abstract

Contrast-enhanced dual energy digital breast tomosynthesis (CE-DE-DBT) is designed to image iodinated masses while suppressing breast anatomical background. Scatter is a problem, especially for high energy acquisition, in that it causes severe cupping artifact and iodine quantitation errors. We propose a patient specific scatter correction (SC) algorithm for CE-DE-DBT. The empirical algorithm works by interpolating scatter data outside the breast shadow into an estimate within the breast shadow. The interpolated estimate is further improved by operations that use an easily obtainable (from phantoms) table of scatter-to-primary-ratios (SPR) - a single SPR value for each breast thickness and acquisition angle. We validated our SC algorithm for two breast emulating phantoms by comparing SPR from our SC algorithm to that measured using a beam-passing pinhole array plate. The error in our SC computed SPR, averaged over acquisition angle and image location, was about 5%, with slightly worse errors for thicker phantoms. The SC projection data, reconstructed using OS-SART, showed a large degree of decupping. We also observed that SC removed the dependence of iodine quantitation on phantom thickness. We applied the SC algorithm to a CE-DE-mammographic patient image with a biopsy confirmed tumor at the breast periphery. In the image without SC, the contrast enhanced tumor was masked by the cupping artifact. With our SC, the tumor was easily visible. An interpolation-based SC was proposed by (Siewerdsen et al., 2006) for cone-beam CT (CBCT), but our algorithm and application differ in several respects. Other relevant SC techniques include Monte-Carlo and convolution-based methods for CBCT, storage of a precomputed library of scatter maps for DBT, and patient acquisition with a beam-passing pinhole array for breast CT. Our SC algorithm can be accomplished in clinically acceptable times, requires no additional imaging hardware or extra patient dose and is easily transportable between sites.

Quantitative evaluation of breast density using a dual‐energy technique on a digital breast tomosynthesis system

“…Ducote et al used 49 and 28 kVp for their images, resulting in lower errors. (b) A correction for x‐ray scatter was absent in our study, even though this is the predominant source of error in breast density measurement . Encouragingly, even the nonuniform phantoms (well‐matched to actual breast tissue in density composition), in which we expected more systematic error, yielded a relatively ideal result with a RMSE value of only 4.49% (compared with 4.17% in uniform phantoms), even though this was the first used of a commercial DBT unit for breast density evaluation (Table ).…”

Phantom-based study exploring the effects of different scatter correction approaches on the reconstructed images generated by contrast-enhanced stationary digital breast tomosynthesis

“…Many of these tap libraries of scatter maps developed by simulation and historical measurements made on phantoms and breasts. 29,35 The maps are selected based on some anatomic features, such as breast thickness. Library-based scatter correction is appealing since additional imaging is not required at the time of the study.…”

“…Typically, this correction is made at the level of the projection image prior to reconstruction and involves applying a map of pixel-specific scatter values to the projection image. However, different algorithms have been proposed in the literature to generate the scatter map, based on applying direct scatter values 28,29 or values incorporating the scatter-to-primary ratio (SPR). 30 In this study, three approaches for generating pixel-specific scatter maps, referred to as ScatterMap direct , ScatterMap SPR , and ScatterMap filtered-SPR (ScatterMap fSPR ), were compared.…”

An update on carbon nanotube‐enabled X‐ray sources for biomedical imaging

“…Additionally, work remains to optimize the post‐acquisition mathematical processing steps that convert the series of 2D projection images into a reconstructed stack of slices that capture 3D information. Specifically, correction algorithms for scatter and noise are being developed, as both pose unique challenges during tomo …”