TECHNIQUE TO OBTAIN POSITRON EMISSION MAMMOGRAPHY IMAGES IN REGISTRATION WITH X-RAY MAMMOGRAMS

X-ray mammograms reveal abnormal tissue densities, while metabolic ima ges identify regions of abnormal metabolism. Conventional nuclear medi cine and radiologic breast images must be acquired at different times with different patient positions making coregistration difficult. Accu rate coregistration of metabolic and x-ray images of the breast is lik ely to be important when acquiring information about the location and diagnosis of suspicious lesions or tumors. Our PEM-I (positron emissio n mammography) system detects metabolic activity within the breast. Th e two planar detectors are integrated into a conventional x-ray mammog raphy 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 proce dures. A coregistration tool has also been developed. A thin plastic s heet with a wire frame protrudes from the side of the upper PEM detect or. With the tool positioned over the suspicious area of the breast, a magnified film density image is made using the available x-ray equipm ent. A radio-opaque rectangular outline of the wire frame is visible o n the film image. During a positron emission metabolic scan, detectors acquire a 49 x 59 mm(2) image of the same region. The PEM detectors c an be positioned anywhere along the width of the breast. This provides an image of a particular region of interest. Several contiguous image s may be combined to provide a complete scan. (C) 1998 American Associ ation of Physicists in Medicine. [S0094-2405(98)01311-X].