Point/Counterpoint. Cone beam x-ray CT will be superior to digital x-ray tomosynthesis in imaging the breast and delineating cancer.

Radiology Department, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
Medical Physics (Impact Factor: 2.64). 03/2008; 35(2):409-11. DOI: 10.1118/1.2825612
Source: PubMed


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    • "In addition to being difficult for mobility challenged individuals, this positioning makes it difficult to effectively image the chest wall and axilla area [25]. Although dedicated breast CT [6] [30] [32] is being investigated as a viable breast imaging technique, many issues still remain to be addressed before it can be introduced in the clinical realm. "
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    ABSTRACT: Digital tomosynthesis imaging is becoming increasingly significant in a variety of medical imaging applications. Tomosynthesis imaging involves the acquisition of a series of projection images over a limited angular range, which, after reconstruction, results in a pseudo-3D representation of the imaged object. The partial separation of features in the third dimension improves the visibility of lesions of interest by reducing the eect of the superimposition of tissues. In breast cancer imaging, tomosynthesis is a viable alternative to standard mammography; however, current algorithms for image reconstruction do not take into account the polyenergetic nature of the x-ray source beam entering the object. This results in inaccuracies in the reconstruction, making quantitative analysis challenging and allowing for beam hardening artifacts. In this paper, we develop a mathematical framework based on a polyenergetic model and develop statistically based iterative methods for digital tomosynthesis reconstruction for breast imaging. By applying our algorithms to simulated data, we illustrate the success of our methods in suppressing beam hardening artifacts, and thus improving the quality of the reconstruction.
    Preview · Article · Jan 2010 · SIAM Journal on Imaging Sciences
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    • "In the case when such changes may be clinically significant, original radiotherapy plan should be adapted or modified to conform to the current (e.g. CBCT) images prior to further treatment to ensure that the intended dose delivery is achieved (Karellas et al 2008). Several studies on dose calculations based on CBCT images have been conducted investigating the feasibility of cone-beam-based plans for dosimetry calculations (Lee et al 2007, 2008, Ding et al 2007b, Nijkamp et al 2008, Yang et al 2007, Yoo and Yin 2006, Richter et al 2008). "
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    ABSTRACT: Cone-beam computed tomography (CBCT) is used for patient alignment before treatment and is ideal for use in adaptive radiotherapy to account for tumor shrinkage, organ deformation and weight loss. However, CBCT images are prone to artifacts such as streaking and cupping effects, reducing image quality and CT number accuracy. Our goal was to determine the optimum combination of cone-beam imaging options to increase the accuracy of image CT numbers. Several phantoms with and without inserts of known relative electron densities were imaged using the Varian on-board imaging system. It was found that CT numbers are most influenced by the selection of field-of-view and are dependent on object size and filter type. Image acquisition in half-fan mode consistently produced more accurate CT numbers, regardless of phantom size. Values measured using full-fan mode can differ by up to 7% from planning CT values. No differences were found between CT numbers of all phantom images with low and standard dose modes.
    Full-text · Article · Oct 2009 · Physics in Medicine and Biology
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    ABSTRACT: The purpose of this study was to investigate the effect of different acquisition parameters and to determine the optimal set of acquisition parameters of projection views (PVs) for the new developed digital breast tomosynthesis (DBT) system. The DBT imaging parameters were optimized using 32 different acquisition sets with six angular ranges (±5°, ±10°, ±13°, ±17°, ±21°, and ±25°) and eight projection views (5, 11, 15, 21, 25, 31, 41, and 51 prjections). In addition to the contrastto-noise ratio (CNR), the artifact spread function (ASF) was used to quantify the in-focus plane artifacts along the z-direction in order to explore the relationship between the acquisition parameters and the image quality. A commercially, available breast-mimicking phantom was imaged to qualitatively verify our results. Our results show that a wide angular range improved the reconstructed image quality in the z-direction. If a large number of projections are acquired, then the electronic noise may dominate the CNR due to reduce the radiation dose per projection. Although increasing angular range was found to improve the vertical resolution, due to greater effective breast thickness, the image quality of microcalcifications in the in-focus plane was also found not to be improved by increasing the noise. Therefore, potential trade-offs of these physical imaging properties must be considered to optimize the acquisition configuration of a DBT system. Our results suggest possible directions for further improvements in DBT systems for high quality imaging.
    No preview · Article · Dec 2012 · Journal- Korean Physical Society
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