First experiment by two-dimensional digital mammography with synchrotron radiation

Abstract

Two-dimensional digital mammography with synchrotron radiation was developed to obtain highcontrast images. The system consisted of a single-crystal monochromator with an asymmetrically re¯ecting silicon h311i crystal, an avalanche multiplication-type pick-up tube camera with ā uorescent plate and lens-coupling system, and a workstation. The preliminary experiment was carried out with a synchrotron light source at the Photon Factory, KEK, in Tsukuba. Breast phantom and human breast specimen were imaged using 20 keV monochromatic synchrotron X-rays. These images were compared with images obtained by a conventional mammography system. The minimal detectable diameter of microcalci®cation on the breast phantom was 165 mm by the two-dimensional synchrotron radiation imaging system and 196 mm by the conventional mammography system. In the breast specimens, microcalci®cation and soft-tissue masses were clearly imaged and their contrasts improved by about 18% and 38%, respectively, in the two-dimensional synchrotron radiation system. The entrance surface dose of the two-dimensional synchrotron radiation system was about 400 mR, which was almost the same value as the 420 mR delivered by the conventional mammography system. Two-dimensional synchrotron radiation digital mammography is considered to be a powerful imaging modality for diagnosing breast tumors.

<title>Optimization of air gap for two-dimensional imaging system using synchrotron radiation</title>

“…Previous SR mammographic experiment performed by Yu [9], showed less than 165 iim microcalicification at 4.5 cm thick breast phantom. Poor detectability of microcacification in our experiment was caused by (1) non-uniformity correction of IP, (2) non-uniformity of 2D incident monochromatic x-ray generated by large monochromator (slight irregularity of mirror surface), (3) instability of x-ray beam due to instability of electronic orbit in storage ring, (4) insufficient dynamic range of the 10 bits available data of IP and IP reader to detect low contrast targets [5], (5) scattered radiation from monochromator with asymmetrical reflection (distance between object and monochromator was only 70 cm due to narrow experimental hutch).…”

“…On the other hand, mammographic system using synchrotron radiation could obtain high resolution and high contrast images compared with conventional mammographic system [1][2][3][4][5][6][7][8][9]. SR has several excellent properties such as high brilliance, broad continuous energy spectrum and small divergence.…”

“…In Japan, 2D SR mammograms of breast phantom were obtained and small microcalcifications, which were not revealed by conventional mammography, are clearly depicted at 2OkeV energy [8,9]. The advantage of the 2D system is easy acquisition of large objects similar to conventional mammography without mechanical scanning apparatus.…”

Optimization of radiography applications using x‐ray beams emitted by compact accelerators. Part I. Monte Carlo study of the hard x‐ray spectrum

“…Theoretical and experimental studies have demonstrated the existence of an optimum energy range both for diagnostic radiology [28][29][30] and mammography examinations. [19][20][21][31][32][33] For example, improvement in image contrast and reduction of patient dose in mammography can be achieved using narrow energy-band x-ray beams in the range of 17-24 keV. Increasingly higher energies become more and more detrimental to the intrinsic image contrast, because of the vanishingly small difference between attenuation coefficients of lesions and normal tissues.…”

High Quality Image of Biomedical Object by X-ray Refraction Based Contrast Computed Tomography

“…This progress has been made on the improvement of detectors, and developments on source and optical elements. Some groups [10][11][12][13][14] have attempted at clinical application to use biomedical tissue as sample. Different optical arrangements and techniques, generally termed as phase-contrast radiography [2][3][4], diffraction-enhanced imaging (DEI) [5][6][7] or dark-field imaging (DFI) [8,9] are being used to increase the density of information carried by the X-ray beam that passes through object and reaches a detector.…”