Trial Information

A Comparison Study of Breast Tomosynthesis Images Reconstructed at 1 Millimeter and 5 Millimeter Slice Thicknesses

Early diagnosis is one of the most important factors in the survival of patients diagnosed
with breast cancer. To aid in the early detection of breast cancer, a new technology, called
tomosynthesis imaging is being developed. The idea behind tomosynthesis imaging is to "look"
at the breast from different points of view by obtaining x-ray flat images from different
angles while the breast does not move, and then mathematically combine these flat images
into a three-dimensional image. The benefit of these three dimensional images is that the
radiologist can look at the different tissues of the breast in their real positions, as
opposed to all the tissues being "flattened" into a flat image, like that of a normal
mammogram. The flat images in mammograms bring about the possibility that normal healthy
tissue sometimes covers up malignant tumors, making them harder, and sometimes impossible,
for the physician to see. In addition, this "flattening" sometimes generates what appears to
be suspicious tissue, but is in reality a superposition of normal healthy tissue. This
effect results in performing an increased number of biopsies that end up being negative for
breast cancer. Since tomosynthesis images of the breast show the tissues in their real
position, these effects can be avoided. It has already been shown by various research labs,
including ours, that this kind of imaging does in fact result in better visualization of
lesions compared to conventional two-dimensional imaging, even without performing
tomosynthesis under ideal conditions.

For tomosynthesis to reach its full potential, it is necessary to perform a large number of
studies to find the optimal way to acquire the tomosynthesis images and the optimal way to
mathematically combine these images to get the three dimensional image. In this study, we
are aiming to find if the resulting three dimensional image should be divided into slices or
layers each representing 1 millimeter (less than one 16th of an inch) of the breast or 5
millimeters (one 5th of an inch) of the breast. The difference between these two thicknesses
in how useful the images are to the radiologist could be important. Up to now, tomosynthesis
imaging has been performed with 1 millimeter slices, but there has been no scientific study
to prove that this is the best slice thickness. We will try to determine if slicing the
image of the breast into thicker slices will make the job of the radiologist easier or not
when deciding to recommend or not a biopsy (laboratory analysis) of what the previous
mammogram found. To find the answer to this question, we will image patients with our
tomosynthesis machine and look at the tomosynthesis images with the thin and thick slices.
The radiologists that read each image will decide if they would have recommended the patient
to get a biopsy based only in each of these images. The recommendations based on the images
with thin slices and the recommendations based on the images with thick slices will be
compared with what was actually recommended using the standard clinical tests. We hope to
show that the images with the thick slices will do as well if not better than those with the
thin slices. Even if the thick slices only do as well as the thin slices, this will show
that creating images with thicker slices is better, since these images can be read faster by
the radiologist.