Ann Katherine Carton PhD, Presenter: Nothing to Disclose

Sara C. Chen MD, Abstract Co-Author: Nothing to Disclose

Michael Albert PhD, Abstract Co-Author: Nothing to Disclose

Emily Fox Conant MD, Abstract Co-Author: Nothing to Disclose

Mitchell Dennis Schnall MD, Abstract Co-Author: Nothing to Disclose

Andrew D. A. Maidment PhD, Abstract Co-Author: Nothing to Disclose

To investigate optimal target/filter, kVp, image quality and MGD for contrast-enhanced digital breast tomosynthesis (CE-DBT). To evaluate this technique with clinical cases.

Technique optimization was performed on a Senographe 2000D (GE, Milwaukee, WI) modified to perform CE-DBT. The choice of the target/filter and kVp was based on exploiting the high attenuation of the iodinated contrast agent (Omnipaque-300, Amersham Healthcare, Princeton, NJ) just above its K-edge at 33 keV. Spectra of Molybdenum and Rhodium targets were extrapolated (Med.Phys. 1997 (12) 1863-1874) to 40-49kVp. The extrapolated spectra were validated against measured aluminum attenuation curves and by comparison to an EGS Monte Carlo simulation of the x-ray source. Various filters were considered to achieve an optimal energy spectrum and to achieve adequate tube-output. MGD were derived for each spectrum from measured tube-outputs, measured HVL and mono-energetic DgN coefficients (Med.Phys. 2002 (29) 869-875) adjusted for the non-perpendicular incidence of the x-ray beam on the breast. Phantoms were fabricated for calibrating the concentration of iodine in terms of the observed x-ray signal in subtracted images form pre- and post-contrast series.

Tube output and HVL were assessed as function of energy. As an example, a Rh target filtered with 0.3mm Cu at 49kVp results in a tube-output at the detector level of 3.9μGy/mAs and a HVL of 3.37mm Al. One pre-contrast and one post-contrast CE-DBT series with this technique for an 8cm 50% glandular-50% fat compressed breast can be performed with a radiation dose similar to that for a 2-view digital mammography exam of 1 breast. In one CE-DBT case of a biopsy-proven malignancy obtained using this technique, a mass-like lesion showed a maximum enhancement of iodine in an area corresponding to the known location of the lesion and MRI findings.

CE-DBT appears practical based on radiation dose and contrast agent sensitivity. Early clinical evidence appears to show a benefit to revealing vascular characteristics of breast lesions.

Carton, A, Chen, S, Albert, M, Conant, E, Schnall, M, Maidment, A, Technical Development of Contrast-enhanced Digital Breast Tomosynthesis.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4418883.html