Prof. Ingvar Andersson: Breast Tomosynthesis in practice
One of the factors limiting the sensitivity of conventional mammography (analogue and digital) is the obscuring effect of dense breast tissue over and underlying a tumour. The problem could be reduced by a Tomographic technique. Tomosynthesis implies acquiring multiple projection images over a certain angular range with mathematical reconstruction of slices parallel to the detector plane. This technique is made possible by the recent development of digital detectors with high efficiency which are capable of acquiring lowdose images with fast read-out and minimal image lag.
Within our group, optimisation studies of Tomosynthesis have been performed regarding factors such as angular range, number of projection images, data collection mode etc.
Tomosynthesis had also been under clinical evaluation in our institution for approx two years. We have analysed a series of breast cancer patients selected on the basis of difficult 2D mammogarms and graded the visibility of the malignancies on digital mammography as well as on tomosynthesis. Furthermore, we have classified the findings according to BIRADS.
The results showed significantly better tumour visibility and more accurate BIRADS classification with Tomosynthesis. Accordingly, the results suggest that Tomosynthesis is a more sensistive technique for the detection of breast cancer than conventional digital mammography. Further studies of the sensitivity and specificity of Tomosynthesis are under way, as well as studies of optimal compression force and radiation dose.
We believe that Tomosynthesis will play an important role in the detection and diagnosis of breast cancer in the future.