Research on dual-modality imaging system for detection of breast cancer – Associate Prof Tania Douglas
Associate Prof Tania Douglas
MRC/UCT Medical Imaging Research Unit, Department of Human Biology, Faculty of Health Sciences, University of Cape Town
Does a dual-modality imaging system lead to improved detection of breast cancer?
A number of breast cancer indicators such as non-calcified masses can be missed by mammography. Although ultrasound does not have the spatial resolution of X-rays, it is able to differentiate tissues of different densities and has been used as an adjunct to X-ray mammography for more than fifty years. In fact, diagnostic breast ultrasound now plays a vitally important role in the detection of cancer. Recent studies based on large numbers of patients have shown that hand-held ultrasound (done in addition to X-ray mammography) has resulted in a significant increase in the breast cancer detection rate. Since hand-held ultrasound does not capture images in specific locations that can be revisited later, automated breast ultrasound systems have been developed.
We are collaborating with a local Cape Town based company, CapeRay Medical (Pty) Ltd, which has developed an innovative platform called the PantoScanner that integrates digital mammography and automated breast ultrasound into a single instrument.
The main objective of the study is to perform simultaneous mammography and ultrasound imaging of the breast using a single system and determine whether this improves the accuracy of diagnosis over using mammography alone. For this purpose, a dual-modality imaging system will be placed and tested in the mammography unit of Groote Schuur Hospital.
The study is intended to provide preliminary data, on the basis of which funding will be sought for a large scale trial to test the dual-modality system.
The X-ray imaging component of the imaging system (the Pantoscanner) has been evaluated in Groote Schuur Hospital. Conventional mammography images have been compared with images from the Pantoscanner. In terms of patient comfort, there were no significant differences between conventional mammography and the Pantoscanner, while an image quality study revealed areas where image quality could be improved – these are being addressed. The operating radiographer found the Pantoscanner to be favourable in terms of ease of use and workflow.
The combined X-ray/ultrasound imaging platform has been refined, by studying ways in which the interface between the breast and the machine can be improved so that the best quality images are obtained while patients enjoy the greatest level of comfort. Methods used to achieve this refinement include the building and imaging of test objects, comparing different imaging settings and selecting those that produce the best images, and simulating the performance of the imaging system under different conditions using specialised software.