Washington: Researchers have developed a new mammography device that allows 3-dimensional (3D) imaging of the breast, offering better image quality than current scans and halving the radiation dose to patients. In breast cancer screening, mammography is the gold standard. But about half of all women who follow standard screening protocol for 10 years will receive a false-positive result that will require additional screening, particularly women who have dense breast tissue, researchers said.
Used in conjunction with mammography, imaging based on nuclear medicine is currently being used as a successful secondary screening alongside mammography to reduce the number of false positive results in women with dense breasts and at higher risk for developing breast cancer, they said. Now, researchers from Thomas Jefferson National Accelerator Facility, Dilon Technologies and University of Florida in the US are hoping to improve this imaging technique, known as molecular breast imaging or breast specific gamma imaging, with better image quality and precise location within the breast, while reducing the amount of radiation dose to the patient for these procedures.
A new device called a variable angle slant hole (VASH) collimator provides all of these benefits and more. “When used in a molecular breast imager, the device has just demonstrated in early studies to capture 3D molecular breast images at higher resolution than current 2D scans in a format that may be used alongside 3D digital mammograms,” said Drew Weisenberger from Jefferson Lab. “These results really focus on the breast. We hope to build on this to perhaps improve the imaging of other organs,” he said.
The new device replaces a component in existing molecular breast imagers, researchers said. While a mammogram uses X-rays to show the structure of breast tissue, molecular breast imagers show tissue function. For instance, cancer tumours are fast growing, so they gobble up certain compounds more rapidly that healthy tissue.
A radiopharmaceutical made of such a compound will quickly accumulate in tumours. A radiotracer attached to the molecule gives off gamma rays, which can be picked up by the molecular breast imager, researchers said.
“You can image that accumulation external to the breast by using a gamma camera,” said Weisenberger. Current molecular breast imaging systems use a traditional collimator, which is essentially a rectangular plate of dense metal with a grid of holes, to “filter” the gamma rays for the camera, researchers said. The collimator only allows the system to pick up the gamma rays that come straight out of the breast, through the holes of collimator, and into the imager. This provides for a clear, well-defined image of any cancer tumours, they said.
Researchers found that using the VASH collimator with an existing breast molecular imaging system, they could get six times better contrast of tumours in the breast, which could potentially reduce the radiation dose to the patient by half from the current levels, while maintaining the same or better image quality.