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John M Lewin

Publications and source records attributed to John M Lewin.

5 recordsLinked to original sources
PubMed2006

Single-shot dual-energy subtraction mammography with electronic spectrum splitting: feasibility.

We present a single-shot dual-energy subtraction mammography technique using an energy sensitive photon counting detector. An electronic threshold near the middle of the X-ray spectrum discriminates between high- and low-energy photons, and allows the simultaneous acquisition of high- and low-energy images which can be combined to suppress anatomical clutter. By setting the electronic threshold close to 33.2 keV (the k-edge of iodine) the system is optimized for dual-energy contrast-enhanced imaging of breast tumors. This method eliminates the need for separate exposures which might otherwise lead to motion artifacts. The method is illustrated in phantom images.

Artificial Intelligence↗
PubMed2004

Digital mammography.

Despite its technical advantages, early clinical trials comparing digital mammography with film mammography for screening have been somewhat disappointing. Digital mammography,however, is in its infancy and can be expected to improve more rapidly than film mammography. Some areas of improvement being observed now include the development of new detector technologies; more powerful and better-designed interpretation workstations; and novel advanced applications, such as tomosynthesis and contrast-enhanced mammography, which are not possible with standard film mammography.

Contrast Media↗
PubMed2003

Dual-energy contrast-enhanced digital subtraction mammography: feasibility.

A technique for demonstrating breast cancers, dual-energy contrast agent-enhanced digital subtraction mammography, was performed in 26 subjects with mammographic or clinical findings that warranted biopsy. The technique consists of high-energy and low-energy digital mammography after administration of iodinated contrast agent. Weighted subtraction of the logarithmic transform of these images is then performed to obtain an image that preferentially shows iodine. Of the 26 subjects, 13 had invasive cancers. Eleven of these tumors enhanced strongly, one enhanced moderately, and one enhanced weakly. The duct in one patient with ductal carcinoma in situ was weakly enhancing. In the other 12 patients, benign tissue enhanced diffusely in two and weakly focally in two. These results indicate that the technique is feasible and worthy of further study.

Adult↗
PubMed2002

Clinical comparison of full-field digital mammography and screen-film mammography for detection of breast cancer.

OBJECTIVE: The purpose of this work is to compare full-field digital mammography and screen-film mammography for the detection of breast cancer in a screening population. SUBJECTS AND METHODS: Full-field digital mammography was performed in addition to screen-film mammography in 6736 examinations of women 40 years old and older presenting for screening mammography at either of two institutions. Two views of each breast were acquired with each technique. The digital and screen-film mammograms were each interpreted independently. In addition to a clinical assessment, each finding was assigned a probability of malignancy for use in receiver operating characteristic analysis. In cases in which the digital and screen-film interpretations differed, a side-by-side analysis was performed to determine the reasons for the discrepancy. With few exceptions, findings detected on either technique were evaluated with additional imaging and, if warranted, biopsy. RESULTS: Additional evaluation was recommended on at least one technique in 1467 cases. These additional evaluations led to 181 biopsies and the detection of 42 cancers. Nine cancers were detected only on digital mammography, 15 were detected only on screen-film mammography, and 18 were detected on both. The difference in cancer detection is not statistically significant (p > 0.1). Digital mammography resulted in fewer recalls than did screenfilm mammography (799 vs 1007, p < 0.001). The difference between the receiver operating characteristic curve area for digital (0.74) and screen-film (0.80) mammography was not significant (p > 0.1). Reasons for discrepant interpretations of cancer were approximately equally distributed among those relating to lesion conspicuity, lesion appearance, and interpretation. CONCLUSION: No significant difference in cancer detection was observed between digital mammography and screen-film mammography. Digital mammography resulted in fewer recalls than did screen-film mammography.

Adult↗