Technique to obtain positron emission mammography images in registration with x‐ray mammograms

Abstract

X-ray mammograms reveal abnormal tissue densities, while metabolic images identify regions of abnormal metabolism. Conventional nuclear medicine and radiologic breast images must be acquired at different times with different patient positions making coregistration difficult. Accurate coregistration of metabolic and x-ray images of the breast is likely to be important when acquiring information about the location and diagnosis of suspicious lesions or tumors. Our PEM-1 (positron emission mammography) system detects metabolic activity within the breast. The two planar detectors are integrated into a conventional x-ray mammography unit. This arrangement simplifies the image registration process by allowing a breast metabolic image to be acquired immediately after performing an x-ray mammogram. The patient is not moved between procedures. A coregistration tool has also been developed. A thin plastic sheet with a wire frame protrudes from the side of the upper PEM detector. With the tool positioned over the suspicious area of the breast, a magnified film density image is made using the available x-ray equipment. A radio-opaque rectangular outline of the wire frame is visible on the film image. During a positron emission metabolic scan, detectors acquire a 49 x 59 mm2 image of the same region. The PEM detectors can be positioned anywhere along the width of the breast. This provides an image of a particular region of interest. Several contiguous images may be combined to provide a complete scan.

Quantification in positron emission mammography (PEM) with planar detectors: contrast resolution measurements using a custom breast phantom and novel spherical hot-spots

“…We have reported previously on the technical details of the instrument[ 11, [2] and more recently on the image coregistration [3] and preliminary clinical trials [4]. We have shown that the system can successfully detect regions of high focal uptake of 'V-FDG with high resolution and 100% specificity.…”

Design and evaluation of an LSO PET detector for breast cancer imaging

“…A number of groups have developed [10][11][12][13][14] or are developing [15][16][17][18] dedicated PET systems that seek to take advantage of the high specificity of FDG PET imaging, at the same time improving sensitivity for breast cancer detection by improving the image resolution and sensitivity relative to whole body PET scanners. One approach has utilized a segmented bismuth germanate ͑BGO͒ scintillator block coupled to a large area position-sensitive photomultiplier tube to create a 7.5ϫ7.5 cm 2 detector.…”

“…One approach has utilized a segmented bismuth germanate ͑BGO͒ scintillator block coupled to a large area position-sensitive photomultiplier tube to create a 7.5ϫ7.5 cm 2 detector. [10][11][12][13] Two of these detectors have been integrated into a conventional Philips mammography system to allow co-registration of PET and mammographic images. They have implemented focal-plane tomography to reconstruct the images.…”

“…However, there is no reason in principle why the detectors described in this paper, arranged in smaller plates, could not be incorporated into existing x-ray systems for planar or limited angle imaging as proposed by others. [11][12][13]18…”

Nuclear imaging of the breast: Translating achievements in instrumentation into clinical use

“…This was the case for the initial PEM designs 61,[98][99][100] and for the original Gamma Medica LumaGem MBI detector. 101 In the breast, coregistration of anatomy and function may be more important than in other organs because breast tissue is so deformable, with few anatomical landmarks.…”