New screening device provides images with 6 times better contrast of breast tumors and approximately half the radiation dose of standard mammography. These results were presented at the 2016 Society of Nuclear Medicine and Molecular Imaging Annual Meeting.1
Approximately half of women who follow standard mammography screening protocol for 10 years will receive a false-positive result requiring additional screening. Dense breast tissue is more likely to produce a false-positive result. Imaging based on nuclear medicine can be used as a successful secondary screening to mammography to reduce the number of false-positive results.
The variable angle slant hole (VASH) collimator is a new device that provides better image quality, precise depth information within the breast, and lower radiation doses. The 3D molecular breast images this device produces have a higher resolution than current 2D images and can be used in conjunction with 3D digital mammography.
The VASH collimator replaces a component in current molecular breast imagers. Molecular breast imagers show function of tissues. Since hypermetabolism characterizes tumors, tumors consume some compounds more quickly than healthy tissues. When such compounds are radioactively labeled, they accumulate rapidly in tumors and emit gamma rays. A molecular breast imager can detect these gamma rays.
The VASH collimator replaces the traditional collimator of a molecular breast imager with one made from stacked tungsten sheets, with each sheet containing an identical array of square holes. The sheets have angled edges on 2 sides. Two small motors slide the individual sheets to modulate the angle of the array of square holes, producing systematic changes to the collimator’s angle of focus during imaging.
A trial of the system used a plastic, artificial breast with 4 beads simulating tumors of varying diameters. The beads were marked with radiotracers. Researchers revealed contrast of breast tumors was 6 times better in images from the VASH collimator, used with a breast molecular imaging system. The improved contrast allows radiation doses to be halved.
“These results really focus on the breast. We hope to build on this to perhaps improve the imaging of other organs,” said Andrew Weisenberger, PhD, chief technology officer at Thomas Jefferson National Accelerator Facility, Newport News, Virginia, and co-author of the study.
1. Guo C, Welch B, Weisenberger A, et al. Performance evaluation of a prototype gamma camera for molecular breast imaging. Oral presentation at: 2016 Society of Nuclear Medicine and Molecular Imaging Annual Meeting; June 11-15, 2016; San Diego, CA. Abstract 256.