Dr. Walter Huda Profile

Dr. Walter Huda

Professor of Radiology at Medical Univ of South Carolina

SPIE Involvement:

Author

Publications (59)

Proceedings Article | 3 March 2012 Paper

Monte Carlo simulation of photon energy and dose-image quality in x-ray imaging

Wenjun He, Eugene Mah, Walter Huda, Hai Yao

Proceedings Volume 8313, 83135C (2012) https://doi.org/10.1117/12.911232

KEYWORDS: Skin, Image quality, Monte Carlo methods, X-rays, Photon transport, X-ray imaging, Diagnostics, X-ray sources, Radiology, Iodine

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Proceedings Article | 3 March 2012 Paper

MCNP simulation of absorbed energy and dose by iodinated contrast agent

Wenjun He, Eugene Mah, Walter Huda, Hai Yao

Proceedings Volume 8313, 83131O (2012) https://doi.org/10.1117/12.911426

KEYWORDS: Optical spheres, Monte Carlo methods, Iodine, X-rays, Diagnostics, Absorption, Computer simulations, Mass attenuation coefficient, Photon transport, Radiology

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Proceedings Article | 17 March 2011 Paper

Monte Carlo modeling of the scatter radiation doses in IR

Eugene Mah, Wenjun He, Walter Huda, Hai Yao, Bayne Selby

Proceedings Volume 7961, 79613H (2011) https://doi.org/10.1117/12.878303

KEYWORDS: Monte Carlo methods, X-rays, Infrared radiation, Photon transport, Infrared imaging, Backscatter, Particles, X-ray sources, Medical imaging, Computer simulations

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Purpose: To use Monte Carlo techniques to compute the scatter radiation dose distribution patterns around patients undergoing Interventional Radiological (IR) examinations. Method: MCNP was used to model the scatter radiation air kerma (AK) per unit kerma area product (KAP) distribution around a 24 cm diameter water cylinder irradiated with monoenergetic x-rays. Normalized scatter fractions (SF) were generated defined as the air kerma at a point of interest that has been normalized by the Kerma Area Product incident on the phantom (i.e., AK/KAP). Three regions surrounding the water cylinder were investigated consisting of the area below the water cylinder (i.e., backscatter), above the water cylinder (i.e., forward scatter) and to the sides of the water cylinder (i.e., side scatter). Results: Immediately above and below the water cylinder and in the side scatter region, values of normalized SF decreased with the inverse square of the distance. For z-planes further away, the decrease was exponential. Values of normalized SF around the phantom were generally less than 10-4. Changes in normalized SF with x-ray energy were less than 20% and generally decreased with increasing x-ray energy. At a given distance from region where the x-ray beam enters the phantom, the normalized SF was higher in the backscatter regions, and smaller in the forward scatter regions. The ratio of forward to back scatter normalized SF was lowest at 60 keV and highest at 120 keV. Conclusion: Computed SF values quantify the normalized fractional radiation intensities at the operator location relative to the radiation intensities incident on the patient, where the normalization refers to the beam area that is incident on the patient. SF values can be used to estimate the radiation dose received by personnel within the procedure room, and which depend on the imaging geometry, patient size and location within the room. Monte Carlo techniques have the potential for simulating normalized SF values for any arrangement of imaging geometry, patient size and personnel location and are therefore an important tool for minimizing operator doses in IR.

Proceedings Article | 16 March 2011 Paper

MCNP simulation of radiation doses distributions in water phantoms simulating interventional radiology patients

Wenjun He, Eugene Mah, Walter Huda, Bayne Selby, Hai Yao

Proceedings Volume 7961, 79613P (2011) https://doi.org/10.1117/12.878271

KEYWORDS: X-rays, Monte Carlo methods, Image-guided intervention, X-ray sources, Image quality, Blood vessels, Photons, Radiology, Image intensifiers, Einsteinium

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Purpose: To investigate the dose distributions in water cylinders simulating patients undergoing Interventional Radiological examinations. Method: The irradiation geometry consisted of an x-ray source, dose-area-product chamber, and image intensifier as currently used in Interventional Radiology. Water cylinders of diameters ranging between 17 and 30 cm were used to simulate patients weighing between 20 and 90 kg. X-ray spectra data with peak x-ray tube voltages ranging from 60 to 120 kV were generated using XCOMP3R. Radiation dose distributions inside the water cylinder (D_w) were obtained using MCNP5. The depth dose distribution along the x-ray beam central axis was normalized to free-in-air air kerma (AK) that is incident on the phantom. Scattered radiation within the water cylinders but outside the directly irradiated region was normalized to the dose at the edge of the radiation field. The total absorbed energy to the directly irradiated volume (E_p) and indirectly irradiated volume (E_s) were also determined and investigated as a function of x-ray tube voltage and phantom size. Results: At 80 kV, the average D_w/AK near the x-ray entrance point was 1.3. The ratio of D_w near the entrance point to D_w near the exit point increased from ~ 26 for the 17 cm water cylinder to ~ 290 for the 30 cm water cylinder. At 80 kV, the relative dose for a 17 cm water cylinder fell to 0.1% at 49 cm away from the central ray of the x-ray beam. For a 30 cm water cylinder, the relative dose fell to 0.1% at 53 cm away from the central ray of the x-ray beam. At a fixed x-ray tube voltage of 80 kV, increasing the water cylinder diameter from 17 to 30 cm increased the E_s/(E_p+E_s) ratio by about 50%. At a fixed water cylinder diameter of 24 cm, increasing the tube voltage from 60 kV to 120 kV increased the E_s/(E_p+E_s) ratio by about 12%. The absorbed energy from scattered radiation was between 20-30% of the total energy absorbed by the water cylinder, and was affected more by patient size than x-ray beam energy. Conclusion: MCNP offers a powerful tool to study the absorption and transmission of x-ray energy in phantoms that can be designed to represent patients undergoing Interventional Radiological procedures. This ability will permit a systematic investigation of the relationship between patient dose and diagnostic image quality, and thereby keep patient doses As Low As Reasonably Achievable (ALARA).

Proceedings Article | 3 March 2011 Paper

Image processing of head CT images using neuro best contrast (NBC) and lesion detection performance

Sameer Tipnis, Diana Vincent, Zoran Rumboldt, Walter Huda

Proceedings Volume 7966, 79661F (2011) https://doi.org/10.1117/12.877574

KEYWORDS: Image processing, Head, Computed tomography, X-ray computed tomography, Image filtering, Image quality, Reconstruction algorithms, CT reconstruction, Diagnostics, Image enhancement

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Purpose: The purpose of this study was to objectively compare lesion detection performance of head CT images reconstructed using filtered back projection (FBP) algorithms with those reconstructed using NBC. Method: The observer study was conducted using the 2-AFC methodology. An AFC experiment consists of 128 observer choices and permits the computation of the intensity needed to achieve 92% correct (I_92%). High values of I_92% corresponds to a poor level of detection performance, and vice versa. Head CT images were acquired at an x-ray tube voltage of 120 kVp with a CTDI_vol value of 75 mGy in a helical scan. Nine randomly selected normal images from three patients and at three anatomical head locations were reconstructed using filtered back projection (FBP) and neuro-best-contrast (NBC) processing. Circular lesions were generated by projecting spheres onto the image plane, followed by blurring function, with lesion sizes of 2.8 mm, 6.5 mm and 9.8 mm used in these experiments. Four readers were used, with 18 experiments performed by each observer (2 processing techniques × 3 lesion sizes × 3 repeats). The experimental order of the 18 experiments was randomized to eliminate learning curve and/or observer fatigue. The ratio R of the I_92% value for NBC to the corresponding I_92% value for FBP was calculated for each observer and each lesion size. Values of R greater than unity indicate that NBC is inferior to FBP, and vice versa. Results: Analysis of data from each observer showed that a total of four data points had R less than unity, and eight data points were greater than unity. Eleven of the twelve individual observer R values with one standard deviation of unity. When data for the four observers were pooled, the resultant average R values were 0.98 ± 0.38, 0.96 ± 0.33 and 1.15 ± 0.45, for the 2.8 mm, 6.5 mm and 9.8 mm lesions respectively. The overall average R for all three lesions sizes was 1.03 ± 0.67. Conclusion: Our AFC investigation has shown no evidence that use of Neuro Best Contrast to process head CT images improves detection of circular, low contrast lesions less than 10 mm.

Proceedings Article | 23 March 2010 Paper

Search field size and lesion detection performance

Sameer Tipnis, Walter Huda, Andrew Hardie, Kent Ogden

Proceedings Volume 7622, 76224U (2010) https://doi.org/10.1117/12.843596

KEYWORDS: Liver, Abdomen, Computed tomography, X-ray computed tomography, Tissues, X-ray imaging, X-rays, Optical spheres, Radiology, Medical imaging

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In this study, we evaluated the ability of an observer to identify abnormal foci on CT and how that ability is affected by changing the search field size from a whole abdomen to the liver region alone. A 2-Alternate Forced Choice (2 AFC) experimental paradigm was used to quantify observer detection performance. Each AFC experiment yielded the intensity needed to achieve 92% accuracy in lesion detection (I92%). Abdominal images were obtained at an x-ray tube voltage of 120 kV with a CTDIvol of 20 mGy. Circular lesions were generated by projecting spheres onto the image plane, followed by blurring function. Five lesion sizes (5 mm, 7 mm, 10 mm, 12 mm, and 15 mm), and four readers who were extensively trained in AFC methodology, were used in the 2AFC experiments. Each experiment was repeated 4 times to improve the experimental precision, as well as to provide an estimate of experimental uncertainty. For each observer, the experimental order of the 40 experiments was randomized to eliminate learning curve and/or observer fatigue. We measured contrast detail slopes for both Abdomen and Liver search field size, and determined ratio of I92% value for Abdomen search field to the corresponding I92% for the Liver search field (i.e., R_abd:liv). Values of Rabd:liv provides quantitative indicator of the relative difficulty of detection lesions in the whole Abdomen relative to lesion detection restricted to the Liver. The slope of the contrast detail curve for the Abdomen search field was -0.03, whereas the corresponding slope for the Liver search field was -0.18. R_abd:liv ranged between 1.3 and 1.6, with an average of 1.4 ± 0.1. The value of Rabd:liv monotonically increased from 1.35 for 5 mm lesions to nearly 1.6 for the largest 15 mm lesion. The results of our study indicate that limiting the area of search to the liver on a CT of the abdomen improves the detection of mass lesions. This finding is almost certainly related to the fact that the liver provides a relatively homogenous background for identifying abnormalities, while the rest of the abdomen is much more heterogeneous. The clinical relevance of our findings is that CT can have limitations for detection of mass lesions outside of the liver, and sizes of masses necessary for detection are larger outside the liver than within.

Proceedings Article | 23 March 2010 Paper

Dose reduction and lesion delectability in abdominal CT

Sameer Tipnis, Walter Huda, Andrew Hardie, Kent Ogden

Proceedings Volume 7622, 76222Q (2010) https://doi.org/10.1117/12.843600

KEYWORDS: X-rays, X-ray computed tomography, Liver, X-ray imaging, Head, Abdomen, Optical simulations, Imaging systems, Diagnostics, X-ray detectors

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Proceedings Article | 23 March 2010 Paper

Iterative reconstruction in image space (IRIS) and lesion detection in abdominal CT

Sameer Tipnis, Ashok Ramachandra, Walter Huda, Andrew Hardie, Joseph Schoepf, Philip Costello, Thomas Flohr, Martin Sedlmair

Proceedings Volume 7622, 76222K (2010) https://doi.org/10.1117/12.843787

KEYWORDS: IRIS Consortium, Computed tomography, Reconstruction algorithms, CT reconstruction, Signal to noise ratio, Image filtering, Image enhancement, Image restoration, Image processing, Diagnostics

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Proceedings Article | 24 February 2010 Paper

Effect of background detail on CD curve slope in CT head images

Kent Ogden, Walter Huda, Sameer Tipnis, Marsha Roskopf

Proceedings Volume 7627, 76271A (2010) https://doi.org/10.1117/12.844425

KEYWORDS: Computed tomography, Head, Critical dimension metrology, Diagnostics, CT reconstruction, Image quality, Scanners, Brain, Liver, Performance modeling

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Proceedings Article | 14 March 2009 Paper

The effect of dose reductions on lesion detection in head CT

Saeed Elojeimy, Walter Huda, Kent Ogden, Ryan Owen, Ehsan Samei, Zoran Rumboldt

Proceedings Volume 7258, 72584Q (2009) https://doi.org/10.1117/12.812051

KEYWORDS: X-ray computed tomography, Head, X-rays, Radiation effects, X-ray imaging, Brain, Basal ganglia, Radiology, Imaging systems, Computed tomography

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Proceedings Article | 13 March 2009 Paper

Contrast detail curves in head CT examinations

Saeed Elojeimy, Walter Huda, Kent Ogden, Ryan Owen, Ehsan Samei, Zoran Rumboldt

Proceedings Volume 7263, 726313 (2009) https://doi.org/10.1117/12.811660

KEYWORDS: Computed tomography, Head, Neck, Tissues, X-ray computed tomography, Basal ganglia, Brain, Radiology, X-ray imaging, X-rays

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Proceedings Article | 25 March 2008 Paper

A comparison of three CT voltage optimization strategies

Kent Ogden, Walter Huda, Mohammad Khorasani, Ernest Scalzetti

Proceedings Volume 6913, 691351 (2008) https://doi.org/10.1117/12.773305

KEYWORDS: X-rays, Tissues, Image quality, Lung, X-ray imaging, X-ray computed tomography, Chest, Diagnostics, Imaging systems, Signal attenuation

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Proceedings Article | 6 March 2008 Paper

Inter-reader variability in alternate forced choice studies

W. Huda, K. Ogden, E. Samei, E. Scalzetti, R. Lavallee, M. Roskopf

Proceedings Volume 6917, 691711 (2008) https://doi.org/10.1117/12.770618

KEYWORDS: Computed tomography, Radiology, Data modeling, Abdomen, Diagnostics, Scanners, Medical imaging, CT reconstruction, Solids, X-ray imaging

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Proceedings Article | 6 March 2008 Paper

Reconstruction filters and contrast detail curves in CT

W. Huda, K. Ogden, E. Samei, E. Scalzetti, R. Lavallee, M. Roskopf, G. Groat

Proceedings Volume 6917, 691710 (2008) https://doi.org/10.1117/12.770530

KEYWORDS: Image filtering, Tissues, Bone, CT reconstruction, X-ray computed tomography, Signal to noise ratio, Computed tomography, Scanners, Performance modeling, Optical filters

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Proceedings Article | 19 March 2007 Paper

How do kV and mAs affect CT lesion detection performance?

W. Huda, K. Ogden, K. Shah, C. Jadoo, E. Scalzetti, R. Lavallee, M. Roskopf

Proceedings Volume 6510, 65104P (2007) https://doi.org/10.1117/12.708498

KEYWORDS: X-rays, X-ray computed tomography, X-ray imaging, Image quality, Performance modeling, Signal to noise ratio, Scanners, CT reconstruction, Tissues, X-ray detectors

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Proceedings Article | 8 March 2007 Paper

A method for analyzing contrast-detail curves

K. Ogden, W. Huda, K. Shah, E. Scalzetti, R. Lavallee, M. Roskopf

Proceedings Volume 6515, 65151H (2007) https://doi.org/10.1117/12.708483

KEYWORDS: Critical dimension metrology, Data acquisition, Data modeling, Computed tomography, Software development, Error analysis, Pathology, Image quality, Signal to noise ratio, Diagnostics

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Proceedings Article | 17 March 2006 Paper

How does mass lesion detection vary with display window width and radiation exposure in computed radiography?

K. Ogden, W. Huda, V. Garg, M. Khan, M. Reichel, M. Roskopf

Proceedings Volume 6146, 614611 (2006) https://doi.org/10.1117/12.650735

KEYWORDS: Radiography, Chromium, Visibility, Image processing, Performance modeling, Optical spheres, Target detection, Sensors, X-ray imaging, X-rays

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Proceedings Article | 17 March 2006 Paper

Incorporating detection tasks into the assessment of CT image quality

E. Scalzetti, W. Huda, K. Ogden, M. Khan, M. Roskopf, D. Ogden

Proceedings Volume 6146, 61460F (2006) https://doi.org/10.1117/12.650746

KEYWORDS: Image quality, Computed tomography, Lung, Liver, Diagnostics, X-ray computed tomography, Chest, Image quality standards, Opacity, Lymphatic system

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Proceedings Article | 2 March 2006 Paper

X-ray tube voltage and image quality in adult and pediatric CT

W. Huda, K. M. Ogden, E. M. Scalzetti, R. L. Lavallee, E. Samei

Proceedings Volume 6142, 61422M (2006) https://doi.org/10.1117/12.649279

KEYWORDS: Tissues, Signal to noise ratio, X-rays, Signal attenuation, Bone, X-ray computed tomography, Lung, Image quality, Head, Abdomen

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Proceedings Article | 20 April 2005 Paper

Use of energy imparted as an optimization tool in CT

Ari Jonisch, Walter Huda, Kent Ogden

Proceedings Volume 5745, (2005) https://doi.org/10.1117/12.595607

KEYWORDS: X-ray computed tomography, Head, Scanners, X-rays, Copper, Computed tomography, Aluminum, Neck, Monte Carlo methods, Abdomen

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Proceedings Article | 15 April 2005 Paper

Quantifying the effect of monitor display settings on observer performance

Kent Ogden, Adam Oberlander, Walter Huda, Marsha Roskopf

Proceedings Volume 5748, (2005) https://doi.org/10.1117/12.594626

KEYWORDS: Image display, Digital imaging, Calibration, Standards development, Mammography, Breast, Medical imaging, Data acquisition, Visualization, Transform theory

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Proceedings Article | 6 April 2005 Paper

Contrast-detail curves in chest radiography

Kent Ogden, Ernest Scalzetti, Walter Huda, Jasjeet Saluja, Robert Lavallee

Proceedings Volume 5749, (2005) https://doi.org/10.1117/12.595578

KEYWORDS: Radiography, Chest, Lung, Chest imaging, Data modeling, Lung cancer, Pathology, Performance modeling, Image processing, Visualization

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Proceedings Article | 6 May 2004 Paper

Optimizing abdominal CT dose and image quality with respect to x-ray tube voltage

Walter Huda, Kent Ogden

Proceedings Volume 5368, (2004) https://doi.org/10.1117/12.535608

KEYWORDS: X-rays, X-ray computed tomography, X-ray imaging, Iodine, Bone, Image quality, Range imaging, X-ray detectors, Scanners, Diagnostics

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The objective of this study was to identify the x-ray tube voltage that results in optimum performance for abdominal CT imaging for a range of imaging tasks and patient sizes. Theoretical calculations were performed of the contrast to noise ratio (CNR) for disk shaped lesions of muscle, fat, bone and iodine embedded in a uniform water background. Lesion contrast was the mean Hounsfield Unit value at the effective photon energy, and image noise was determined from the total radiation intensity incident on the CT x-ray detector. Patient size ranging from young infants (10 kg) to oversized adults (120 kg), with CNR values obtained for x-ray tube voltages ranging from 80 to 140 kV. Patients of varying sizes were modeled as an equivalent cylinder of water, and the mean section dose (D) was determined for each selected x-ray tube kV value at a constant mAs. For each patient size and lesion type, we identified an optimal kV as the x-ray tube voltage that yields a maximum value of the figure of merit (CNR2/D). Increasing the x-ray tube voltage from 80 to 140 kV reduced lesion contrast by 11% for muscle, 21% for fat, 35% for bone and 52% for iodine, and these reductions were approximately independent of patient size. Increasing the x-ray tube voltage from 80 to 140 kV increased a muscle lesion CNR relative to a uniform water background by a factor of 2.6, with similar trends observed for fat (2.3), bone (1.9) and iodine (1.4). The improvement in lesion CNR with increasing x-ray tube voltage was highest for the largest sized patients. Increasing the x-ray tube voltage from 80 to 140 kV increased the patient dose by a factor of between 5.0 and 6.2 depending on the patient size. For small sized patients (10 and 30 kg) and muscle lesions, best performance is obtained at 80 kV; however, for adults (70 kg) and oversized adults (120 kg), the best performance would be obtained at 140 kV. Imaging fat lesions was best performed at 80 kV for all patients except for oversized adults, where 140 kV offers the best imaging performance. For high Z lesions of bone and iodine, imaging performance generally degrades with increasing kV for all patient sizes, with the degree of degradation largest for the smallest patients. We conclude that 80 kV is optimal with respect to radiation dose in abdominal CT for all pediatric patients. For adults, 80 kV is the x-ray voltage of choice for high Z lesions, whereas 140 kV would generally be the voltage of choice of lesions that have an atomic number similar to that of water.

Proceedings Article | 4 May 2004 Paper

How do radiographic techniques affect mass lesion detection performance in digital mammography?

Walter Huda, Kent Ogden, Ernest Scalzetti, Eric Dudley, David Dance

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.535672

KEYWORDS: X-rays, Digital mammography, Image quality, Digital imaging, Mammography, Breast, Solids, Performance modeling, X-ray imaging, Visibility

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Proceedings Article | 4 May 2004 Paper

How does the concentration of iodine in enhancing lesions relate to image quality in head CT?

Aaron Fischman, Robert Dixon, Walter Huda, Kent Ogden, Kristin Lieberman, Marsha Roskopf

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.535645

KEYWORDS: Iodine, Image enhancement, Computed tomography, Head, Signal to noise ratio, Image quality, Image processing, Receivers, Diagnostics, Tumors

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Patients undergoing head CT examinations with iodinated contrast received 100 cc of Iohexol 240 injected intravenously by hand. We developed a software package to align non-contrast and contrast head CT images, and obtain the “difference image” consisting of the iodine enhancement within a given lesion. This “difference image” of the iodine enhancement was added to the non-contrast study at reduced intensities. The signal to noise ratio (SNR) for detecting the added iodine was taken to be directly proportional to the concentration of contrast in the lesion. The visibility of the lesion enhancement in this composite image was compared with the original contrast image using a six-point scale ranging from 5 (no observable difference) to 0 (unacceptable). Two radiologists evaluated head CT images of eleven metastatic lesions. The iodine concentration required to generate an image quality rank of 3, deemed to be satisfactory for diagnosis (S), was determined. We also performed a Receiver Operating Characteristic (ROC) study to identify the iodine concentration corresponding to an area under the ROC curve of 0.95, which corresponds to the detection threshold (D) for each lesion. Reducing the intensity to 50% resulted in an average image qualtiy score S of 3, suggesting that it may be possible to reduce the administered iodine by a half in head CT examinations with no significant loss of diagnostic performance. The average iodine concentration at the detection threshold D was 16%. The average S:D ratio was 3.8 ± 1.7, and was similar for both readers. The value of S was independent of enhancement characteristics, whereas the detection threshold D correlated inversely with the size and intensity of the iodine enhancement. The resultant S:D ratio correlated with the lesion area (r² = 0.31), mean lesion intensity (r² = 0.44), and the product of the mean lesion intensity and the lesion area (r² = 0.37). Our results indicate that the SNR of enhancing lesions in head CT that is needed to satisfy radiologists is about a factor of four greater than the SNR required for iodine detection.

Proceedings Article | 5 June 2003 Paper

General approach to optimizing digital mammography with respect to radiation risk

Kent Ogden, Walter Huda, Ernest Scalzetti

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.479972

KEYWORDS: X-rays, Image quality, Digital mammography, Imaging systems, X-ray imaging, Radiology, Breast cancer, Diagnostics, Radiography, Mammography

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Proceedings Article | 22 May 2003 Paper

How does lesion location affect detection performance in digital mammography?

Walter Huda, Kent Ogden, Ernest Scalzetti, Joon Park, Roger Hunt, David Dance

Proceedings Volume 5034, (2003) https://doi.org/10.1117/12.480085

KEYWORDS: Mammography, Breast, Digital mammography, Signal detection, Convolution, Digital imaging, Radiography, Visibility, X-rays, Solids

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Proceedings Article | 3 May 2002 Paper

Optimizing the x-ray photon energy for digital radiographic imaging systems

Walter Huda, Harry Kissi, Kent Ogden, John Boone

Proceedings Volume 4682, (2002) https://doi.org/10.1117/12.465608

KEYWORDS: X-rays, X-ray imaging, Iodine, Calcium, Image quality, Quantum efficiency, Imaging systems, X-ray detectors, Radiography, Tissues

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Proceedings Article | 12 April 2002 Paper

Observer performance and radiographic technique factors in digital mammography

Anthony Sajewicz, Walter Huda, Denis Hseuh, Kent Ogden, Ernest Scalzetti, David Dance

Proceedings Volume 4686, (2002) https://doi.org/10.1117/12.462668

KEYWORDS: Visibility, Digital mammography, Mammography, X-rays, Medical imaging, Digital imaging, Breast, X-ray imaging, Imaging systems, Image sensors

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Proceedings Article | 7 August 2001 Paper

Clinical performance of a prototype flat-panel digital detector for general radiography

Walter Huda, Ernest Scalzetti, Marsha Roskopf, Robert Geiger

Proceedings Volume 4323, (2001) https://doi.org/10.1117/12.435506

KEYWORDS: Image quality, Image processing, Radiography, Sensors, Digital imaging, Bone, Digital image processing, Spine, X-rays, Chest

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Proceedings Article | 28 June 2001 Paper

How does magnification affect image quality and patient dose in digital subtraction angiography?

Nikolaos Gkanatsios, Walter Huda, Keith Peters

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430927

KEYWORDS: Image quality, Iodine, Angiography, Image intensifiers, Skin, Image acquisition, Digital imaging, Receptors, Medical imaging, Ionization

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Proceedings Article | 28 June 2001 Paper

Comparison of the imaging physics performance of a prototype flat-panel detector with a 400-speed screen-film system

Walter Huda, Kent Ogden, Marsha Roskopf, Charles Rush

Proceedings Volume 4320, (2001) https://doi.org/10.1117/12.430954

KEYWORDS: Sensors, Imaging systems, Digital imaging, Physics, X-rays, Spatial resolution, Image processing, Image resolution, Prototyping, Digital image processing

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Proceedings Article | 28 May 2001 Paper

Optimizing softcopy display of radiographic images acquired with a prototype flat-panel detector

Walter Huda, Kent Ogden, Ernest Scalzetti, Mahmoud El-kaissi

Proceedings Volume 4319, (2001) https://doi.org/10.1117/12.428091

KEYWORDS: Image quality, Sensors, Image processing, Prototyping, Radiography, Chest, Flat panel displays, Skull, Neck, X-ray detectors

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Proceedings Article | 25 April 2000 Paper

Radiographic technique factors and imaging performance in digital mammography

Walter Huda, Guoying Qu, Zhenxue Jing, Barbara Steinbach, Janice Honeyman-Buck

Proceedings Volume 3977, (2000) https://doi.org/10.1117/12.384532

KEYWORDS: X-rays, Digital mammography, Digital imaging, X-ray detectors, Sensors, Breast, Imaging systems, X-ray imaging, Mammography, Signal detection

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Proceedings Article | 14 April 2000 Paper

How does observer training affect imaging performance in digital mammography?

Walter Huda, Guoying Qu, Zhenxue Jing, Barbara Steinbach, Janice Honeyman-Buck

Proceedings Volume 3981, (2000) https://doi.org/10.1117/12.383117

KEYWORDS: Digital mammography, Breast, Digital imaging, Receivers, Mammography, Mendelevium, Radiology, Argon, Image acquisition, Image display

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Proceedings Article | 28 May 1999 Paper

Spatial-frequency-dependent DQE performance of a CsI:Tl-based x-ray detector for digital mammography

Zhenxue Jing, Walter Huda, James Walker, Won Choi

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349489

KEYWORDS: X-rays, X-ray detectors, Photons, Charge-coupled devices, Quantum efficiency, Sensors, Spatial frequencies, Digital mammography, Iodine, X-ray imaging

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Monte Carlo calculations were performed to generate the point spread functions of x-ray photons absorbed in a CsI:Tl x-ray detector at the x-ray energies normally used in mammography (i.e., 20 keV to 50 keV). The corresponding modulation transfer functions [MTF(f)] for the CsI:Tl screen were also computed, taking into account the optical spread of light within the CsI:Tl crystals. The computed MTF(f)s were dominated by scintillation light lateral dispersion within the CsI:Tl screen. For the photon energy range encountered in digital mammography, the MTF(f) was a minimum at an x-ray photon energy just above the k-edge of Iodine (33 keV). Noise propagation theory for a cascaded imaging system was subsequently used to derive a theoretical expression for the detector DQE(f), including the dependence of DQE(f) on the spatial distribution of x-ray photon energy deposition. Detector performance was investigated as a function of x-ray exposure, CCD electronic noise, coupling efficiency of the fiber optical coupler, and the CCD quantum efficiency. Although most of the x-rays are absorbed via the photoelectric effect, the deposited x-ray energy spread within the CsI:Tl screen from the emission of characteristic x-rays can have a marked effect on detector performance, and the DQE(f) was found to decrease rapidly with photon energy just above the Iodine K-edge. X-ray exposure levels to the detector should be greater than or equal to 5 mR with a CCD electronic noise of approximately 20 electrons rms to ensure that DQE(f) performance is not significantly degraded at the spatial frequencies important in digital mammography (i.e., 0 to 10 lp/mm). Light dispersion within the CsI:Tl crystals was the major factor degrading imaging system DQE(f) at higher spatial frequencies. Optical coupling efficiency and CCD quantum efficiency are important system design parameters, which need to be maintained at a relatively high value. An optical coupling efficiency of approximately 0.7, and a CCD quantum efficiency of approximately 0.4, would still permit system DQE values greater than 60% at a spatial frequency of 5 lp/mm.

Proceedings Article | 24 May 1999 Paper

Effects of radiation dose and display contrast on low-contrast phantom image visibility

Charles Chamberlain, Walter Huda, Andrij Wojtowycz

Proceedings Volume 3663, (1999) https://doi.org/10.1117/12.349661

KEYWORDS: Radiography, Chromium, Radiation effects, Digital imaging, Visibility, Interference (communication), Image enhancement, Image processing, Image display, Radiology

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Proceedings Article | 24 July 1998 Paper

Energy-selective laser-based x-ray source for mammography

Andrzej Krol, Jean-Claude Kieffer, Walter Huda, Zhiming Jiang, Charles Chamberlain, Jianfan Yu

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317088

KEYWORDS: X-rays, Electrons, X-ray sources, Mammography, Optical filters, Photons, Plasma, Laser energy, X-ray imaging, Solids

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Proceedings Article | 24 July 1998 Paper

Detective quantum efficiency of a CsI:Tl scintallator-based scanning slot x-ray detector for digital mammography

Zhenxue Jing, Walter Huda, James Walker, Won Choi

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317062

KEYWORDS: X-rays, X-ray detectors, Scintillators, Sensors, Charge-coupled devices, X-ray imaging, X-ray optics, Digital mammography, Fiber optics, Quantum efficiency

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Proceedings Article | 24 July 1998 Paper

Signal-to-noise ratio and radiation dose as a function of photon energy in mammography

Walter Huda, Andrzej Krol, Zhenxue Jing, John Boone

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317035

KEYWORDS: Signal to noise ratio, X-rays, Breast, Mammography, Monte Carlo methods, Photonic microstructures, Image quality, X-ray imaging, Radiology, Tissues

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Proceedings Article | 24 June 1998 Paper

Improved SPECT reconstruction of Tc-99m sestamibi distribution in breast tissue

Andrzej Krol, David Feiglin, George Gagne, Walter Huda, Gwen Tillapough-Fay, Bradford Hellwig, Deaver Thomas

Proceedings Volume 3338, (1998) https://doi.org/10.1117/12.310923

KEYWORDS: Breast, Tissues, Single photon emission computed tomography, Reconstruction algorithms, Magnetic resonance imaging, Heart, Image processing, Image restoration, Tomography, Visualization

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Proceedings Article | 26 March 1998 Paper

Wavelet CFAR detector for mass detection in mammography

Dongwei Chen, John Harris, Andrew Laine, Walter Huda

Proceedings Volume 3391, (1998) https://doi.org/10.1117/12.304916

KEYWORDS: Wavelets, Sensors, Mammography, Detection and tracking algorithms, Digital mammography, Signal detection, Breast cancer, Tumors, Wavelet transforms, Detection theory

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Proceedings Article | 2 May 1997 Paper

Performance of a CsI:TL-screen-based scanning slot detector for digital mammography

Zhenxue Jing, Walter Huda, James Walker, Won Choi

Proceedings Volume 3032, (1997) https://doi.org/10.1117/12.273994

KEYWORDS: X-rays, X-ray detectors, Sensors, Charge-coupled devices, Scintillation, Spatial resolution, Digital mammography, Prototyping, Signal detection, Polymer optical fibers

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Proceedings Article | 16 April 1997 Paper

ROC comparison between digital mammography and screen-film using an anthropomorphic breast phantom

Guoying Qu, Walter Huda, Barbara Steinbach, Janice Honeyman-Buck

Proceedings Volume 3036, (1997) https://doi.org/10.1117/12.271291

KEYWORDS: Digital mammography, Imaging systems, Breast, Mammography, Radiography, Receivers, Medical imaging, Visualization, Electronic filtering, Digital imaging

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Proceedings Article | 1 May 1996 Paper

RIS requirements to support a PACS infrastructure

Janice Honeyman-Buck, Meryll Frost, Robert Moser, Walter Huda, Edward Staab

Proceedings Volume 2711, (1996) https://doi.org/10.1117/12.239239

KEYWORDS: Picture Archiving and Communication System, Databases, Ultrasonography, Chromium, Radiology, Imaging systems, Computing systems, Digital imaging, Interfaces, Data acquisition

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The purpose of this research and development effort was to solve several image management problems in Picture Archiving and Communications Systems (PACS). First, the patient and study information associated with images was not always correct and only rarely complete. This was due to human error in entering information on a console, and from incomplete data entry forms on image producing equipment. Second, in at least one area, Computed Radiography, the task of data entry was so time consuming that throughput suffered. The third problem was image routing, both within the Department of Radiology and throughout the hospital. The last identified problem was the lack of a common key between the PACS database the Radiology Information System (RIS) database so reports and images could be associated with each other. An RIS/PACS interface was developed in which RIS packets were sent to a PACS process at the time request forms were printed. These packets were parsed to various acquisition computers based on the modality type where they were stored in a MSQL Database for use in validating studies as they were completed prior to being transferred to PACS. DICOM header information from incoming studies were `matched' to a database entry based on the medical record number and modality. Whenever possible, an additional match was made on an accession number stored in the header. A match could result in the DICOM header being completed with detailed information about the patient, patient location, requesting service, and the procedure or study. In the case of the Kodak CR unit, patient and study information were sent directly to the CR workstation where they were accessible using a bar code interface at the time plates were ready to be processed. Routing within the radiology department was determined by comparing the RIS procedure code with an MSQL table to locate the workstation(s) used for viewing this type of study. The data of birth was used to determine whether the study should also be routed to a pediatric workstation. Finally, the accession number as assigned by the RIS was placed in the image header to allow matching of images and reports. The RIS/PACS system now matches patient, study, and other RIS information to PACS images to have improve routing, display, information accuracy, and efficiency. This system was built using a legacy RIS system without an HL7 interface, but the processes were created in a modular fashion that will make them easy to convert to HL7 when an expected new RIS is put in place. In order for a PACS to operate efficiently in an information intensive environment, the data associated with images must be correct, complete, and must contain `hooks' to other information systems in a medical center. The RIS/PACS interface is crucial to a successful PACS implementation.

Proceedings Article | 11 April 1996 Paper

Significance of exposure data recognizer modes in computed radiography

Walter Huda, Richard Slone, Manuel Arreola, Beverly Hoyle, Zhenxue Jing

Proceedings Volume 2708, (1996) https://doi.org/10.1117/12.237823

KEYWORDS: Chromium, Image processing, Radiography, Skull, Imaging systems, Image quality, Computing systems, Collimation, Tissues, Manufacturing

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Proceedings Article | 11 April 1996 Paper

Imaging characteristics of plastic scintillating fiber screens for mammography

Zhenxue Jing, Walter Huda, James Walker, Won Choi

Proceedings Volume 2708, (1996) https://doi.org/10.1117/12.237827

KEYWORDS: X-rays, Spatial frequencies, Mammography, Tin, Quantum efficiency, Sensors, Digital mammography, Modulation transfer functions, Spatial resolution, Photons

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Proceedings Article | 27 March 1996 Paper

Optimizing the tonescale display of computed radiography images

Walter Huda, Richard Slone, Beverly Hoyle, Xhenxue Jing, Janice Honeyman-Buck

Proceedings Volume 2712, (1996) https://doi.org/10.1117/12.236850

KEYWORDS: Chromium, Chest imaging, Radiography, Imaging systems, Image display, Lung, Image quality, Chest, Manufacturing, Image processing

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Proceedings Article | 12 May 1995 Paper

Comparison of a dyadic wavelet image enhancement algorithm with unsharp masking and median filtering for mammography

Yunong Xing, Walter Huda, Andrew Laine, Jian Fan, Barbara Steinbach, Janice Honeyman-Buck

Proceedings Volume 2434, (1995) https://doi.org/10.1117/12.208745

KEYWORDS: Image processing, Signal to noise ratio, Wavelets, Digital filtering, Image enhancement, Mammography, Interference (communication), Image filtering, Computer simulations, Signal processing

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Proceedings Article | 8 May 1995 Paper

Computed radiography acceptance testing

Walter Huda, Manuel Arreola, Zhenxue Jing

Proceedings Volume 2432, (1995) https://doi.org/10.1117/12.208372

KEYWORDS: Chromium, Image processing, Spatial resolution, Radiography, Manufacturing, Computing systems, Image enhancement, Copper, Radiology, Image quality

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Proceedings Article | 27 April 1995 Paper

Preliminary evaluation of a high-resolution workstation for diagnostic interpretation of portable radiographs

Janice Honeyman-Buck, Walter Huda, Carole Palmer, Meryll Frost, Robert Moser, Edward Staab

Proceedings Volume 2431, (1995) https://doi.org/10.1117/12.207650

KEYWORDS: Diagnostics, Image quality, Chromium, Radiography, Radiology, Human-machine interfaces, Image resolution, Picture Archiving and Communication System, Digital imaging, Medicine

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A cost effectiveness study on the feasibility of using computed radiography (CR) instead of screen-film methods for portable radiographs indicates that we could only justify CR if film were eliminated. Before purchasing CR equipment, we needed to evaluate the use of softcopy to replace film for routine clinical use. The evaluation had to cover image quality, human factors, and efficiency measures. Screen-film radiographs were digitized and used to simulate CR in two studies. The first study evaluated the quality of digitized images and the workstation user interface. Twenty-one radiographs were selected at random from scopes in the radiology department, were digitized, and transferred to a megascan workstation. Five radiologists were asked to assess the quality of the images and the ease of operation of the workstation while an observer recorded their comments and scores. The second study evaluated the feasibility of using the workstation in a clinical environment. Four radiologists read adult and pediatric portable images in film and softcopy format. Reports were evaluated for differences and timing statistics were kept. The results of the first study indicate that image quality may be acceptable for diagnostic purposes and suggests some changes in the user interface. Newborn infant images were the least acceptable in softcopy, largely due to magnification artifacts introduced when viewing very small images. The evaluation was based on a digitizer as a simulator for a CR unit and the digitizer did not exhibit the same resolution characteristics as CR. Films that were unacceptable from the digitizer are expected to be acceptable with CR. The results of the second study indicated that the high resolution diagnostic workstation could be used in a clinical setting, and that the diagnostic readings were not significantly different between film and softcopy displays. The results also indicated that, depending on the radiologist and the type of images, more time was required to read from the workstation and that the increased time was spent using window/level and magnification/roam functions. This preliminary study suggests that the high resolution workstation developed at the University of Florida has adequate quality and functionality to be used for diagnostic interpretation of portable radiographs if given high resolution images. However, further investigation is indicated before we eliminate film in a CR environment.

Proceedings Article | 17 April 1995 Paper

Imaging performance and CR film density

Walter Huda, Jon Williams, Clifford Belden, Jonathan Williams

Proceedings Volume 2436, (1995) https://doi.org/10.1117/12.206850

KEYWORDS: Chromium, Image processing, Digital imaging, Radiography, Imaging systems, Radiology, Strontium, Image display, Ranging, X-rays

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Proceedings Article | 11 October 1994 Paper

Quantitative evaluation of wavelet-based image processing algorithms

Zhenxue Jing, Yisheng Zheng, Walter Huda, Andrew Laine, Jian Fan, Yunong Xing

Proceedings Volume 2303, (1994) https://doi.org/10.1117/12.188807

KEYWORDS: Image processing, Signal to noise ratio, Wavelets, Interference (communication), Image enhancement, Algorithm development, Mammography, Signal processing, Mathematical modeling, Visibility

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Proceedings Article | 8 July 1994 Paper

Simulated phantom images for optimizing wavelet-based image processing algorithms in mammography

Yunong Xing, Walter Huda, Andrew Laine, Jian Fan

Proceedings Volume 2299, (1994) https://doi.org/10.1117/12.179251

KEYWORDS: Image processing, Computer simulations, Wavelets, Mammography, Interference (communication), Signal detection, Image enhancement, Signal processing, Wavelet transforms, Algorithm development

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Proceedings Article | 1 May 1994 Paper

Performance of an ICU teleradiology system using computed radiography input

Walter Huda, Janice Honeyman-Buck, Carole Palmer, Meryll Frost, Edward Staab

Proceedings Volume 2164, (1994) https://doi.org/10.1117/12.174004

KEYWORDS: Chromium, Image processing, Image resolution, Spatial resolution, Image quality, Image transmission, Radiography, Computing systems, Teleradiology, Radiology

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Proceedings Article | 14 September 1993 Paper

Hexagonal wavelet processing of digital mammography

Andrew Laine, Sergio Schuler, Walter Huda, Janice Honeyman-Buck, Barbara Steinbach

Proceedings Volume 1898, (1993) https://doi.org/10.1117/12.154543

KEYWORDS: Mammography, Image enhancement, Image processing, Image filtering, Wavelets, Digital mammography, Fourier transforms, Breast, Wavelet transforms, Multiscale representation

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Proceedings Article | 8 September 1993 Paper

Network-bandwidth and archive-storage requirements model for PACS

Walter Huda, Janice Honeyman, Meryll Frost, Carole Palmer, Edward Staab

Proceedings Volume 1899, (1993) https://doi.org/10.1117/12.152885

KEYWORDS: Radiology, Picture Archiving and Communication System, Data acquisition, Mammography, Fluoroscopy, Data storage, Radiography, Chest, Magnetic resonance imaging, Data archive systems

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Proceedings Article | 29 July 1993 Paper

Adaptive multiscale processing for contrast enhancement

Andrew Laine, Shuwu Song, Jian Fan, Walter Huda, Janice Honeyman, Barbara Steinbach

Proceedings Volume 1905, (1993) https://doi.org/10.1117/12.148666

KEYWORDS: Mammography, Wavelet transforms, Wavelets, Breast, Digital mammography, Image enhancement, Visualization, Tissues, Multiscale representation, Pathology

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Proceedings Article | 30 June 1993 Paper

Importance of computed radiography image display parameters in orthopedic imaging

Walter Huda, W. Montgomery, Manuel Arreola, Beverly Hoyle, C. Bush

Proceedings Volume 1897, (1993) https://doi.org/10.1117/12.146960

KEYWORDS: Image processing, Chromium, Tissues, Image quality, Radiography, Image display, Orthopedic imaging, Radiology, Printing, Image enhancement

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