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Record W2047504807 · doi:10.1118/1.1493216

Material‐specific analysis using coherent‐scatter imaging

2002· article· en· W2047504807 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueMedical Physics · 2002
Typearticle
Languageen
FieldEngineering
TopicAdvanced X-ray and CT Imaging
Canadian institutionsLondon Health Sciences CentreRobarts Clinical TrialsWestern University
Fundersnot available
KeywordsAttenuationOpticsImage intensifierMaterials scienceConvolution (computer science)Artifact (error)ScatteringNoise (video)PhysicsComputer scienceImage (mathematics)Artificial intelligence

Abstract

fetched live from OpenAlex

Coherent-scatter computed tomography (CSCT) is a novel imaging method we are developing to produce cross-sectional images based on the low-angle (<10 degrees) scatter properties of tissue. At diagnostic energies, this scatter is primarily coherent with properties dependent upon the molecular structure of the scatterer. This facilitates the production of material-specific maps of each component in a conglomerate. Our particular goal is to obtain quantitative maps of bone-mineral content. A diagnostic x-ray source and image intensifier are used to acquire scatter patterns under first-generation CT geometry. An accurate measurement of the scatter patterns is necessary to correctly identify and quantify tissue composition. This requires corrections for exposure fluctuations, temporal lag in the intensifier, and self-attenuation within the specimen. The effect of lag is corrected using an approximate convolution method. Self-attenuation causes a cupping artifact in the CSCT images and is corrected using measurements of the transmitted primary beam. An accurate correction is required for reliable density measurements from material-specific images. The correction is shown to introduce negligible noise to the images and a theoretical expression for CSCT image SNR is confirmed by experiment. With these corrections, the scatter intensity is proportional to the number of scattering centers interrogated and quantitative measurements of each material (in g/cm3) are obtained. Results are demonstrated using both a series of poly(methyl methacrylate) (PMMA) sheets of increasing thickness (2-12 mm) and a series of 5 acrylic rods containing varying amounts of hydroxyapatite (0-0.400 g/cm3), simulating the physiological range of bone-mineral density (BMD) found in trabecular bone. The excellent agreement between known and measured BMD demonstrates the viability of CSCT as a tool for densitometry.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.845
Threshold uncertainty score0.998

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0030.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.015
GPT teacher head0.230
Teacher spread0.215 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it