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Composite x‐ray image assembly for large‐field digital mammography with one‐ and two‐dimensional positioning of a focal plane array
Author(s) -
Halama Gary,
McAdoo James,
Liu Hong
Publication year - 1998
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598177
Subject(s) - mammography , digital mammography , cardinal point , field (mathematics) , optics , medical imaging , plane (geometry) , image plane , medical physics , physics , image (mathematics) , computer vision , computer science , medicine , artificial intelligence , geometry , mathematics , breast cancer , cancer , pure mathematics
To demonstrate the feasibility of a novel large‐field digital mammography technique, a 1024 × 1024 pixel Loral charge‐coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one‐ and two‐dimensional scan sequences to obtain 950 × 1800 pixel and 3600 × 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high‐resolution, large‐field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x‐ray image, the mosaic must be repositioned four times, with an x‐ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x‐ray source and the patient. The high‐precision motorized translation stages and the fiber‐coupled‐scintillating‐screen–CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.