David A. Scaduto, PhD, DABR

Portland, Maine-based medical physicist. Research Instructor of Radiology at Stony Brook Medicine interested in contrast-enhanced breast imaging, diagnostic imaging, art, design and beautiful ideas.

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2️⃣0️⃣1️⃣2️⃣🏃🏻‍♂️2️⃣0️⃣2️⃣1️⃣ In 2012, I trained for my first marathon while studying for Part 1 of the American Board of Radiology Medical Physicist certifying exam. Last weekend, in recognition and celebration of successfully completing the Part 3 Oral exam in May (and because I like numerical anagrams), I ran the same marathon as a Board-certified Medical Physicist. Proud and privileged to push my mind, body and spirit to the limits. (at Maine Marathon) https://www.instagram.com/p/CU0DZe9L5PlW_gh-l7j2-juVcm2uz_wLJwxNvQ0/?utm_medium=tumblr

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An Opinion Writer Argued Jill Biden Should Drop the ‘Dr.’ (Few Were Swayed.)

Many women said Joseph Epstein’s suggestion in The Wall Street Journal was blatantly sexist and underscored the way men often dismiss women’

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‎The Anthropocene Reviewed: Humanity's Temporal Range on Apple Podcasts

‎Show The Anthropocene Reviewed, Ep Humanity's Temporal Range - Mar 26, 2020

Beautiful, haunting, hopeful.

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‘Everything Is Uncharted’: New Yorkers Confront Life Amid a Coronavirus Shutdown

With restrictions tightened on businesses and daily activity, residents are grappling with uncertainty about resources, health care and thei

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Optimized Technique for Reducing Breast Compression in Digital Breast Tomosynthesis

David A. Scaduto, PhD, Stony Brook Medicine, Stony Brook, New York

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Western Bay, Maine

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I had a great time presenting my abstracts on minimal compression and angular range in digital breast tomosynthesis at this year’s RSNA. Thanks for all of the feedback and for a great conference!

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The Republican tax plan could financially devastate graduate students

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Experimental Characterization of a Direct Conversion Amorphous Selenium Detector with Thicker Conversion Layer for Dual‐Energy Contrast‐Enhanced Breast Imaging

David A. Scaduto, Olivier Tousignant, Wei Zhao

Abstract

Purpose

Dual-energy contrast-enhanced imaging is being investigated as a tool to identify and localize angiogenesis in the breast, a possible indicator of malignant tumors. This imaging technique requires that x-ray images are acquired at energies above the k-shell binding energy of an appropriate radiocontrast agent. Iodinated contrast agents are commonly used for vascular imaging, and require x-ray energies greater than 33 keV. Conventional direct conversion amorphous selenium (a-Se) flat panel imagers for digital mammography show suboptimal absorption efficiencies at these higher energies.

Methods

We use spatial-frequency domain image quality metrics to evaluate the performance of a prototype direct conversion flat panel imager with a thicker a-Se layer, specifically fabricated for dual-energy contrast-enhanced breast imaging. Imaging performance was evaluated in a prototype digital breast tomosynthesis (DBT) system. The spatial resolution, noise characteristics, detective quantum efficiency and temporal performance of the detector were evaluated for dual-energy imaging for both conventional full-field digital mammography (FFDM) and DBT.

Results

The zero-frequency detective quantum efficiency of the prototype detector is improved by approximately 20% over the conventional detector for higher-energy beams required for imaging with iodinated contrast agents. The effect of oblique entry of x-rays on spatial resolution does increase with increasing photoconductor thickness, specifically for the most oblique views of a DBT scan. Degradation of spatial resolution due to focal spot motion was also observed. Temporal performance was found to be comparable to conventional mammographic detectors.

Conclusions

Increasing the a-Se thickness in direct conversion flat panel imagers results in better performance for dual-energy contrast-enhanced breast imaging. The reduction in spatial resolution due to oblique entry of x-rays is appreciable in the most extreme clinically relevant cases, but may not profoundly affect reconstructed images due to the algorithms and filters employed. Degradation to projection domain spatial resolution is thus outweighed by the improvement in detective quantum efficiency for high-energy x-rays.

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Hooded!

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Clinically Translating Contrast-Enhanced Breast Imaging

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Optimization of contrast‐enhanced breast imaging: Analysis using a cascaded linear system model

Yue-Houng Hu, David A. Scaduto, Wei Zhao

Abstract

Purpose

Contrast-enhanced (CE) breast imaging involves the injection contrast agents (i.e., iodine) to increase conspicuity of malignant lesions. CE imaging may be used in conjunction with digital mammography (DM) or digital breast tomosynthesis (DBT) and has shown promise in improving diagnostic specificity. Both CE-DM and CE-DBT techniques require optimization as clinical diagnostic tools. Physical factors including x-ray spectra, subtraction technique, and the signal from iodine contrast, must be considered to provide the greatest object detectability and image quality. We developed a cascaded linear system model (CLSM) for the optimization of CE-DM and CE-DBT employing dual energy (DE) subtraction or temporal (TE) subtraction.

Methods

We have previously developed a CLSM for DBT implemented with an a-Se flat panel imager (FPI) and filtered backprojection (FBP) reconstruction algorithm. The model is used to track image quality metrics — modulation transfer function (MTF) and noise power spectrum (NPS) — at each stage of the imaging chain. In this study, the CLSM is extended for CE breast imaging. The effect of x-ray spectrum (varied by changing tube potential and the filter) and DE and TE subtraction techniques on breast structural noise was measured was studied and included as a deterministic source of noise in the CLSM. From the two-dimensional (2D) and three-dimensional (3D) MTF and NPS, the ideal observer signal-to-noise ratio (SNR), also known as the detectability index (d′), may be calculated. Using d′ as a FOM, we discuss the optimization of CE imaging for the task of iodinated contrast object detection within structured backgrounds.

Results

Increasing x-ray energy was determined to decrease the magnitude of structural noise and not its correlation. By performing DE subtraction, the magnitude of the structural noise was further reduced at the expense of increased stochastic (quantum and electronic) noise. TE subtraction exhibited essentially no residual structural noise at the expense of increased quantum noise, even over that of the DE case. For DE subtraction, optimization of dose weighting to the HE view (fh) results in the minimization of quantum noise. Both subtraction weighting factor (wSub) and the iodine contrast signal were dependent on the LE and HE x-ray spectra. To best detect a 5 mm Gaussian lesion with 5 mg/ml of iodine within a 4 cm thick breast, it was found that the high energy (HE) view should be acquired with a tube potential of 47 kVp (W/Ti spectrum) and the low energy (LE) view with a potential of 23 kVp (W/Rh spectrum). Due to the complete removal of structural noise, TE subtraction produced much higher d′ than DE subtraction both as a function of mean glandular dose and iodine concentration.

Conclusions

We have shown the effect of increasing x-ray energy as well as projection domain subtraction on breast structural noise. Further, we have exhibited the utility of the CLSM for DE and TE subtraction CE imaging in the optimization of imaging parameters such as x-ray energy, fh, and wSub as well as guiding the understanding of their effects on image contrast and noise.

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A Drone Tour Of One Of The Most Anticipated Buildings Of 2017

Herzog & de Meuron's Hamburg Concert Hall opens in January. See it only as a drone can.

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Beautiful view of Chicago from last night's Siemens event at the Shedd Aquarium at RSNA.

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The Government of the United States... gives to bigotry no sanction, to persecution no assistance.

George Washington, in his letter to the Hebrew Congregation at Newport, RI (1790)

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To commemorate the 119th anniversary of the discovery of x-rays on November 8, the Metropolitan Museum of Art shared this piece, made just months after Roentgen’s discovery in 1895. The date is also commemorated as the International Day of Radiology, coming just one day after the International Day of Medical Physics on November 7, itself chosen to commemorate the birthday of radiation pioneer Marie Curie.

X-Ray of Samples of Various Materials

Artist: Josef Maria Eder (Austrian, Krems an der Donau, 1855–1944 Kitzbühel) and Artist: Eduard Valenta (Austrian, 1857–1937) Date: 1896 Medium: Photogravure Dimensions: Image: 9 1/16 × 6 15/16 in. (23 × 17.7 cm) Plate: 10 5/16 × 8 ¼ in. (26.2 × 20.9 cm) Sheet: 17 5/16 × 13 15/16 in. (44 × 35.4 cm) Classification: Photographs Credit Line: Purchase, Alfred Stieglitz Society Gifts, Joyce F. Menschel Photography Library Fund, and Maureen and Noel Testa Gift, 2011 Accession Number: 2011.66.5

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Today is the 120th anniversary of Wilhelm Roentgen’s discovery of x-rays, as well as the International Day of Radiology!

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Happy International Day of Medical Physics! Learn about this profession at the cross-section of physics, medicine and technology.