【私のイチオシ！】RSNA2011注目の演題：辻岡 勝美先生(藤田保健衛生大学）

【私のイチオシ！】コーナーでは、先生方が注目する面白そうなセッションや口演・ポスター発表等についてご紹介します。

辻岡 勝美先生(藤田保健衛生大学医療科学部放射線学科）が注目するセッションはこちらです!

SSA20-02
Design for a Dynamic Bowtie Achieving a Piecewise-Linear Attenuation Profile
S. S . Hsieh et al
DATE: Sunday, November 27 2011
TIME: 10:55 AM – 11:05 AM
LOCATION: S404AB
●PURPOSE
A dynamic CT bowtie filter capable of modulating its attenuation profile with time may provide superior image quality and reduced patient dose when compared to static bowties. We present a design for such a dynamic bowtie, which may be especially relevant when used with photon-counting detectors, because the reduction in dynamic range enabled by the dynamic bowtie may translate into the usability of detectors with modest count rate capability.

SSA20-04
Volume-of-Interest Imaging for High Image Quality at Reduced Dose in Dedicated Female Breast CT
D. Kolditz et al
DATE: Sunday, November 27 2011
TIME: 11:15 AM – 11:25 AM
LOCATION: S404AB
●PURPOSE
Generally, the complete breast cross-section is scanned in breast CT to avoid truncation artifacts in the reconstructed images. The aim of this study was to develop and evaluate a volume-of-interest (VOI) approach to increase image quality for a sub-volume at reduced total dose.

SSA20-08
Effect of Shaped Filters Designed for Breast CT on Dose and Image Quality
F. Lueck et al
DATE: Sunday, November 27 2011
TIME: 11:55 AM – 12:05 PM
LOCATION: S404AB
●PURPOSE
The purpose of this study was to investigate the effect of shaped filters specifically designed for a dedicated breast CT scanner on dose and image quality.

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Dual-Energy CT
William P . Shuman et al
DATE: Tuesday, November 29 2011
TIME: 07:15 AM – 08:15 AM
LOCATION: E352
●LEARNING OBJECTIVES
1) Improve basic knowledge and skills relevant to the clinical practice of dual energy CT. 2) Access the results of very recent research into dual energy CT and assess applications to routine clinical practice. 3) Apply principles of critical thinking to ideas on the latest applications from experts in the field of dual energy CT of the liver, pancreas, heart, lungs, adrenals, kidneys/GU, and joints. 4) Assess the potential of Dual energy CT to enhance clinical practice and problem-solving.

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SSG14-02
Fully Four-Dimensional Motion Estimation and Motion Compensation of Cardiac CT
Q. Tang et al
DATE: Tuesday, November 29 2011
TIME: 10:40 AM – 10:50 AM
LOCATION: S403B
●PURPOSE
To develop a new class of fully 4-dimensional image reconstruction algorithm for cardiac CT: an iterative algorithm that alternates two methods, motion estimation (ME) method to estimate the time-dependent motion vector field (MVF) of the heart from image data, and motion compensated reconstruction (MCR) method to reconstruct images using the estimated MVF and projection data.

SSG14-05
Deconvolution-based Quantitative Myocardial Perfusion Measurement with Dual-Energy CT Perfusion Imaging
A. So et al
DATE: Tuesday, November 29 2011
TIME: 11:10 AM – 11:20 AM
LOCATION: S403B
●PURPOSE
We compared quantitative myocardial perfusion (MP) measurement between dual-energy CT (DECT) and single-energy CT (SECT) without and with beam hardening (BH) correction (BHC).

SSG14-06
Simulate Left Ventricle Motion: Design and Development of a Pulsating Cardiac Phantom with a Twist Mechanism
H. Cao et al
DATE: Tuesday, November 29 2011
TIME: 11:20 AM – 11:30 AM
LOCATION: S403B
●PURPOSE
The pulsating cardiac phantom is a useful tool for evaluation image quality of cardiac applications. The current cardiac phantom only moves in 2D (X-Y) dimensions, but real Left Ventricle (LV) motion is in 4D dimensions (X, Y, Z and twist motion). The purpose of this paper is to demonstrate the design and fabrication of new pulsating cardiac phantom with a twist mechanism to simulate real LV motion.

SSG14-07
Determining Temporal Noise Contributions in Dynamic Scans: Applications to 2D and 3D Functional Imaging
J. C . Gatenby et al
DATE: Tuesday, November 29 2011
TIME: 11:30 AM – 11:40 AM
LOCATION: S403B
●PURPOSE
In functional imaging, one of the main parameters in determining the quality of the scan is the temporal signal to noise ratio (tSNR), as opposed to the system signal to noise ratio (sSNR). tSNR is always lower than the sSNR due to temporal signal fluctuations caused mainly by physiological processes (respiration and cardiac). A simple formula for the partition of this noise is to define the total variance in the temporal signal as the sum of two independent noise sources. However it is not normally possible to separate these two sources. This abstract describes how this can be accomplished using noise scans.

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SSJ21-02
Semi-empirical Method to Formulate Tissue-equivalent Materials for Calibration and Quality Assurance in CT and Radiotherapy
I. Yohannes et al
DATE: Tuesday, November 29 2011
TIME: 03:10 PM – 03:20 PM
LOCATION: S403B
●PURPOSE
We propose a semi-empirical method to formulate tissue-equivalent materials (TEMs) that can be used for quality assurance procedures both in computed tomography (CT) and radiotherapy as well as to obtain the relationship between CT number and electron density or stopping power for photon or particle (electrons, protons and carbon ions) therapy planning systems, respectively.

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CODE:SSK16-01
Prediction of Human Observer Performance on a Lesion-detection Task in CT Using Channelized Hotelling Observer
L. Yu et al
DATE: Wednesday, November 30 2011
TIME: 10:30 AM – 10:40 AM
LOCATION: S403B
● PURPOSE
Efficient optimization of CT protocols demands a quantitative approach to predicting human observer performance on specific tasks at various scan settings. The goal of this work was to investigate how well a channelized Hotelling observer (CHO) can predict human observer performance on a 2-alternative forced choice (2AFC) lesion-detection task at various dose levels.

CODE:SSK16-02
Will X-ray Phase Contrast Imaging Revolutionize Diagnostic Imaging?
R. Raupach et al
DATE: Wednesday, November 30 2011
TIME: 10:40 AM – 10:50 AM
LOCATION: S403B
● PURPOSE
To quantify the inherent properties, the potential, and the limitations of X-ray phase contrast imaging (PCI).

CODE:SSK16-03
Imaging Performance of a Dedicated Cone-Beam CT System for Musculoskeletal Extremities
W. Zbijewski et al
DATE: Wednesday, November 30 2011
TIME: 10:50 AM – 11:00 AM
LOCATION: S403B
●PURPOSE
A prototype cone-beam CT (CBCT) scanner dedicated to musculoskeletal extremities has been developed, providing a compact platform for weight-bearing and combined planar and 3D imaging. The first performance evaluation is presented, including radiation dose, soft-tissue visibility, spatial resolution, artifacts, and image quality in cadaveric specimens.

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CODE:SSK15-03 10:50 AM
Implementation and Validation of a Real-time Monte Carlo Software Tool for Patient-specific Dose Calculations
W. Chen et al
DATE: Wednesday, November 30 2011
TIME: 10:50 AM – 11:00 AM
LOCATION: S403A
●PURPOSE
Monte Carlo simulation is an established technique for dose calculation in diagnostic radiology. The main drawback is its high computational cost. The aim of this study was to develop a real-time Monte Carlo software tool for patient-specific dose calculations using graphics processing units (GPUs).

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CODE:LL-PHS-WE11B
Comparison of 320-Row CT Image and 640-Row CT Image on Area Detector CT (ADCT): Improvement of Image Continuity on
Three-dimensional CT
K. Tsujioka et al
DATE: Wednesday, November 30 2011
TIME: 12:45 PM – 01:15 PM
LOCATION: Lakeside Learning Center
●SUMMARY
In case of 3D display with CT, proper evaluation can not be given only with the spatial resolution and slice thickness in the Z-axis direction. Even for a 320-row ADCT, implementation of 640-row image reconstruction provides far better 3D CT images. Image reconstruction shall be carried out in 640 rows for three dimensional CT of clinical cases.

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CODE:SSM20-02
Potential of High-Z Contrast Agents in Clinical Computed Tomography
T. Nowak et al
DATE: Wednesday, November 30 2011
TIME: 03:10 PM – 03:20 PM
LOCATION: S404AB
●PURPOSE
Currently, only iodine- and barium-based contrast media (CM) are used in clinical computed tomography (CT). However, high-Z metals such as ytterbium, tungsten or gold would produce a higher contrast at equal mass density for the X-ray spectra used in clinical CT. Using such materials might allow for significant dose reductions in contrast enhanced CT (CE-CT). The purpose of this study was to quantify the potential for dose reduction when using CM based on heavy metals.

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CODE:SSQ17-05
Clinical Evaluation of Phase-contrast Computed Tomography (PCCT) for Detection of Liver Tumors
P. B . Noel et al
DATE: Thursday, December 01 2011
TIME: 11:10 AM – 11:20 AM
LOCATION: S404AB
●PURPOSE
To evaluate the diagnostic value of phase-contrast computed tomography (PCCT) for detection of liver tumors. Cancer, especially in the liver, is one of the leading causes of death worldwide. Thus, early detection and precise treatment monitoring is crucial for full recovery of patients. Current computed tomography (CT) systems do not provide enough soft-tissue contrast for detection of soft-tissue tumors. These drawbacks result from the low sensitivity of CT or in other words from the minor differences in linear attenuation coefficients between tissues. On the contrary, PCCT has the potential to enhance the soft-tissue information even without injecting a contrast agent.

CODE:SSQ17-06
Scatter Properties of Compact Geometry Cone-Beam CT Systems
W. Zbijewskin et al
DATE: Thursday, December 01 2011
TIME: 11:20 AM – 11:30 AM
LOCATION: S404AB
●PURPOSE
New cone-beam CT (CBCT) systems (e.g., extremity and ENT imaging) involve a compact geometry with elevated x-ray scatter compared to other CBCT embodiments (e.g., C-arms) and more challenging scatter correction. We investigate the complex scatter distributions of compact-geometry CBCT via Monte Carlo calculations to elucidate the factors governing scatter magnitude, high-frequency heterogeneity, the performance of antiscatter grids, and strategies for scatter correction.

CODE:SSQ17-07 11:30 AM
Optimal Energy Thresholds for Breast CT Using Photon Counting Detectors
S. J . Glick et al
DATE: Thursday, December 01 2011
LOCATION: S404AB
●CONCLUSION
It was observed that projection based weighting can provide up to 40% improvement in SNR compared to energy integrating detectors for breast CT.

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CODE:LL-PHS-TH9B
Development of Automatic Contrast-enhanced Control (ACEC) for Abdominal CT Scan Using Scanography (Simulation of Injection
Amount of Contrast Media Using Quantitative Contrast Media Injection Data)
K. Tsujioka et al
DATE: Thursday, December 01 2011
TIME: 12:45 PM – 01:15 PM
LOCATION: Lakeside Learning Center
●PURPOSE
We have been proposing a method for determining the injection amount of contrast media (Auto Contrast Enhance Control: ACEC) through use of scanography. This method determines the injection amount of contrast media by calculating the X-ray absorption at each CT cross-section based on the scanographical data available in advance when conducting CT scan, and then estimating the CT value increase for the target organ. In this study, following the fundamental experiment using phantoms, we compared and considered the X-ray absorption index in the slice direction on the pre-obtained scanography and the CT value changes in the organ in a real-life clinical case wherein the contrast media amount was not changed.