bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐D‐18A‐01: Evaluation of Three Commercial Metal Artifact Reduction Methods for CT Simulations in Radiation Therapy Treatment Planning
Authors: Huang J , Kerns J , Nute J , Liu X , Stingo F , Followill D , Mirkovic D , Howell R , Kry S 
Published: July 2014

Purpose:To evaluate three commercial metal artifact reduction methods (MAR) in the context of radiation therapy treatment planning.Methods:Three MAR strategies were evaluated: Philips O‐MAR, monochromatic imaging using Gemstone Spectral Imaging (GSI) dual energy CT, and monochromatic imaging with metal artifact reduction software (GSIMARs). The Gammex RMI 467 tissue characterization phantom with several metal rods and two anthropomorphic phantoms (pelvic phantom with hip prosthesis and head phantom with dental fillings), were scanned with and without (baseline) metals. Each MAR method was evaluated based on CT number accuracy, metal size accuracy, and reduction in the severity of streak artifacts. CT number difference maps between the baseline and metal scan images were calculated, and the severity of streak artifacts was quantified using the percentage of pixels with >40 HU error (“bad pixels”).Results:Philips O‐MAR generally reduced HU errors in the RMI phantom. However, increased errors and induced artifacts were observed for lung materials. GSI monochromatic 70keV images generally showed similar HU errors as 120kVp imaging, while 140keV images reduced errors. GSI‐MARs systematically reduced errors compared to GSI monochromatic imaging. All imaging techniques preserved the diameter of a stainless steel rod to within ±1.6mm (2 pixels). For the hip prosthesis, O‐MAR reduced the average % bad pixels from 47% to 32%. For GSI 140keV imaging, the percent of bad pixels was reduced from 37% to 29% compared to 120kVp imaging, while GSI‐MARs further reduced it to 12%. For the head phantom, none of the MAR methods were particularly successful.Conclusion:The three MAR methods all improve CT images for treatment planning to some degree, but none of them are globally effective for all conditions. The MAR methods were successful for large metal implants in a homogeneous environment (hip prosthesis) but were not successful for the more complicated case of dental artifacts.
WE‐D‐18A‐06: Estimating Local Noise Power Spectrum From a Few CT Scans
Authors: Zeng R , Gavrielides M , Li Q , Petrick N , Sahiner B , Myers K 
Published: July 2014

Purpose:The traditional way to estimate CT NPS is by averaging the power spectrum of many noisy scans. When only a few scans are available, regions of interests are often extracted from different locations to obtain sufficient samples to estimate NPS, thus ignoring the nonstationarity of CT noise. This approach to estimating NPS does not accurately reflect the location‐variant characteristics of CT noise. The purpose of this work is to develop a method to estimate local NPS from only a few CT scans.Methods:As a result of the FBP reconstruction algorithm, the CT NPS presents the following radial property: the shape of the radial profile of the NPS is almost constant, determined by the reconstruction filter, and the magnitude varies with angle depending on the object attenuation map. Therefore, a shape function and an angular magnitude function are sufficient to describe the CT NPS. Based on this property, the dimensionality of the NPS is greatly reduced and we are able to derive a radial NPS method to estimate the NPS from only a few scans.Results:We applied the radial NPS method to simulated CT scans of a nonuniform object. The results showed that the local NPS estimated from only 6 scans using the radial method was very close to the NPS estimated using the traditional method from 400 scans, according to normalized mean squared error (NMSE) and the signal detectability based on an NPS‐prewhitening Hoteling model observer. We also applied this method to physical phantom scans. Good accuracy was again achieved from only 6 scans using the radial NPS method.Conclusion:The radial NPS method was shown to be accurate and efficient in estimating the local NPS of FBP reconstructed CT images. This method is readily extendable to estimating the NPS of helical CT scans.
WE‐D‐9A‐03: CSDF: A Color Extension of the Grayscale Standard Display Function
Authors: Kimpe T , Avanaki A , Marchessoux C , Rostang J , Espig K , Piepers B , Xthona A 
Published: July 2014

Purpose:Use of color images in medical imaging has increased significantly the last few years. As of today there is no agreed standard on how color information needs to be visualized on medical color displays, resulting into large variability of color appearance and it making consistency and quality assurance a challenge. This paper presents a proposal for an extension of DICOM GSDF towards color.Methods:Visualization needs for several color modalities (multimodality imaging, nuclear medicine, digital pathology, quantitative imaging applications…) have been studied. On this basis a proposal was made for desired color behavior of color medical display systems and its behavior and effect on color medical images was analyzed.Results:Several medical color modalities could benefit from perceptually linear color visualization for similar reasons as why GSDF was put in place for greyscale medical images. An extension of the GSDF (Greyscale Standard Display Function) to color is proposed: CSDF (color standard display function). CSDF is based on deltaE2000 and offers a perceptually linear color behavior. CSDF uses GSDF as its neutral grey behavior. A comparison between sRGB/GSDF and CSDF confirms that CSDF significantly improves perceptual color linearity. Furthermore, results also indicate that because of the improved perceptual linearity, CSDF has the potential to increase perceived contrast of clinically relevant color features.Conclusion:There is a need for an extension of GSDF towards color visualization in order to guarantee consistency and quality. A first proposal (CSDF) for such extension has been made. Behavior of a CSDF calibrated display has been characterized and compared with sRGB/GSDF behavior. First results indicate that CSDF could have a positive influence on perceived contrast of clinically relevant color features and could offer benefits for quantitative imaging applications.Authors are employees of Barco Healthcare
WE‐D‐9A‐05: Medical Hyperspectral Imaging for the Detection of Head and Neck Cancer in Animal Models
Authors: Fei B , Lu G , Pike R , Wang D , Chen G 
Published: July 2014

Purpose:The objective of this study is to develop hyperspectral imaging technology and advanced image analysis methods for the detection of head and neck cancer.Methods:A head and neck tumor xenograft model was used in the experiment. The M4E head and neck cancer cells with green fluorescence protein (GFP) were injected into nude mice. Hyperspectral images were acquired from the tumor‐bearing mice using a CRI Maestro invivo imaging camera. The wavelength setting was defined within the range of 450–950 nm with 2 nm increments. Two advanced image classification methods were developed to classify normal and cancer tissue on hyperspectral images. In the first method, a tensor‐based computation and modeling framework was proposed for the analysis of hyperspectral images for cancer detection. In the second classification method, support vector machines were incorporated into a minimum spanning forest algorithm for differentiating cancer tissue from normal tissue. The classification results were validated by the GPP images of the same animals.Results:The tensor‐based classification method can distinguish between malignant tissue and healthy tissue with an average sensitivity of 97.0% and an average specificity of 91.4% in tumor‐bearing mice. The minimum spanning forest algorithm also achieved a high accuracy of more than 97.0% in the animal model.Conclusion:The hyperspectral imaging and classification technology has been demonstrated in animal models and can have many potential applications in cancer research and management.This research is supported in part by NIH grants (R01CA156775, R21CA176684, and P50CA128301) and Georgia Cancer Coalition Distinguished Clinicians and Scientists Award.
WE‐D‐9A‐06: Open Source Monitor Calibration and Quality Control Software for Enterprise Display Management
Authors: Bevins N , Vanderhoek M , Lang S , Flynn M 
Published: July 2014

Purpose:Medical display monitor calibration and quality control present challenges to medical physicists. The purpose of this work is to demonstrate and share experiences with an open source package that allows for both initial monitor setup and routine performance evaluation.Methods:A software package, pacsDisplay, has been developed over the last decade to aid in the calibration of all monitors within the radiology group in our health system. The software is used to calibrate monitors to follow the DICOM Grayscale Standard Display Function (GSDF) via lookup tables installed on the workstation. Additional functionality facilitates periodic evaluations of both primary and secondary medical monitors to ensure satisfactory performance. This software is installed on all radiology workstations, and can also be run as a stand‐alone tool from a USB disk. Recently, a database has been developed to store and centralize the monitor performance data and to provide long‐term trends for compliance with internal standards and various accrediting organizations.Results:Implementation and utilization of pacsDisplay has resulted in improved monitor performance across the health system. Monitor testing is now performed at regular intervals and the software is being used across multiple imaging modalities. Monitor performance characteristics such as maximum and minimum luminance, ambient luminance and illuminance, color tracking, and GSDF conformity are loaded into a centralized database for system performance comparisons. Compliance reports for organizations such as MQSA, ACR, and TJC are generated automatically and stored in the same database.Conclusion:An open source software solution has simplified and improved the standardization of displays within our health system. This work serves as an example method for calibrating and testing monitors within an enterprise health system.
WE‐E‐BRD‐01: HDR Brachytherapy I: Overview of Clinical Application and QA
Authors: Libby B , Showalter T 
Published: July 2014

With the increased usage of high dose rate (HDR) brachytherapy and the introduction of dedicated image guided brachytherapy suites, it is necessary to review the processes and procedures associated with safely delivering these treatments in the expedited time scales that dedicated treatment suites afford.The speakers will present the clinical aspects of switching from LDR to HDR treatments, including guidelines for patient selection, and the clinical outcomes comparing LDR to HDR. The speakers will also discuss the HDR treatment process itself, because the shortened clinical timeline involved with a streamlined scan/plan/treat workflow can introduce other issues. Safety and QA aspects involved with the streamlined process, including increased personnel required for parallel tasks, and possible interfering tasks causing delays in patient treatments will also be discussed.Learning Objectives:

To understand the clinical aspects of HDR Brachytherapy, including common clinical indications, patient selection, and the evolving evidence in support of this therapeutic modality
To review the current prominent clinical trials for HDR brachytherapy
To interpret the established guidelines for HDR brachytherapy quality assurance for implementation into practical clinical settings.
To introduce the basic requirements for image guided brachytherapy
WE‐E‐9A‐01: Ultrasound Elasticity
Authors: Emelianov S , Hall T , Bouchard R 
Published: July 2014

Principles and techniques of ultrasound‐based elasticity imaging will be presented, including quasistatic strain imaging, shear wave elasticity imaging, and their implementations in available systems. Deeper exploration of quasistatic methods, including elastic relaxation, and their applications, advantages, artifacts and limitations will be discussed. Transient elastography based on progressive and standing shear waves will be explained in more depth, along with applications, advantages, artifacts and limitations, as will measurement of complex elastic moduli. Comparisons will be made between ultrasound radiation force techniques, MR elastography, and the simple A mode plus mechanical plunger technique. Progress in efforts, such as that by the Quantitative Imaging Biomarkers Alliance, to reduce the differences in the elastic modulus reported by different commercial systems will be explained.Dr. Hall is on an Advisory Board for Siemens Ultrasound and has a research collaboration with them, including joint funding by R01CA140271 for nonlinear elasticity imaging.Learning Objectives:

Be reminded of the long history of palpation of tissue elasticity for critical medical diagnosis and the relatively recent advances to be able to image tissue strain in response to an applied force.
Understand the differences between shear wave speed elasticity measurement and imaging and understand the factors affecting measurement and image frame repletion rates.
Understand shear wave propagation effects that can affect measurements, such as essentially lack of propagation in fluids and boundary effects, so important in thin layers.
Know characteristics of available elasticity imaging phantoms, their uses and limitations.
Understand thermal and cavitational limitations affecting radiation force‐based shear wave imaging.
Have learning and references adequate to for you to use in teaching elasticity imaging to residents and technologists.
Be able to explain how elasticity measurement and imaging can contribute to diagnosis of breast and prostate cancer, staging of liver fibrosis, age estimation of deep veinous fhrombosis, confirmation of thermal lesions in the liver after RF ablation.
WE‐E‐16A‐01: Medical Physics Economics Update
Authors: Goodwin J , Dirksen B , White G 
Published: July 2014

Radiology and Medical Physics reimbursement for Medicare services is constantly changing. In this presentation we will review the proposed reimbursement rules and levels for 2015 and compare them with those currently in effect for 2014. In addition, we will discuss the challenges that may lie ahead for the medical physics profession as the Centers for Medicare and Medicaid Services (CMS) moves away from a fee for service payment model and towards one of prospective payment.Learning Objectives:

Understand the differences in the Medicare reimbursement systems for outpatient departments as opposed to physicians and free standing centers.
Learn the proposed Medicare rules for 2015 and how they may affect Radiology and Medical Physics revenues.
Be aware of possible long term changes in reimbursement and how they may affect our employers, our pocket books and our profession.
WE‐E‐BRE‐01: An Image‐Based Skeletal Dosimetry Model for the ICRP Reference Adult Female – Internal Electron Sources
Authors: O' Reilly S , Sinclair L , Maynard M , Rajon D , Wayson M , Marshall E , Bolch W 
Published: July 2014

Purpose:Limitations seen in previous skeletal dosimetry models, which are still employed in commonly used software today, include the lack of consideration of electron escape and cross‐fire from cortical bone, the modeling of infinite spongiosa, the disregard of the effect of varying cellularity on active marrow self‐irradiation, and the lack of use of the more recent ICRP definition of a 50 micron surrogate tissue region for the osteoprogenitor cells – shallow marrow. These limitations were addressed in the present dosimetry model.Methods:Electron transport was completed to determine specific absorbed fractions to active marrow and shallow marrow of the skeletal regions of the adult female. The bone macrostructure was obtained from the whole‐body hybrid computational phantom of the UF series of reference phantoms, while the bone microstructure was derived from microCT images of skeletal region samples taken from a 45 year‐old female cadaver. The target tissue regions were active marrow and shallow marrow. The source tissues were active marrow, inactive marrow, trabecular bone volume, trabecular bone surfaces, cortical bone volume and cortical bone surfaces. The marrow cellularity was varied from 10 to 100 percent for active marrow self‐irradiation. A total of 33 discrete electron energies, ranging from 1 keV to 10 MeV, were either simulated or modeled analytically.Results:The method of combining macro‐ and microstructure absorbed fractions calculated using MCNPX electron transport was found to yield results similar to those determined with the PIRT model for the UF adult male in the Hough et al. study.Conclusion:The calculated skeletal averaged absorbed fractions for each source‐target combination were found to follow similar trends of more recent dosimetry models (image‐based models) and did not follow current models used in nuclear medicine dosimetry at high energies (due to that models use of an infinite expanse of trabecular spongiosa).
WE‐E‐BRE‐04: Dual Focal Spot Dose Painting for Precision Preclinical Radiobiological Investigations
Authors: Stewart J , Lindsay P , Jaffray D 
Published: July 2014

Purpose:Recent progress in small animal radiotherapy systems has provided the foundation for delivering the heterogeneous, millimeter scale dose distributions demanded by preclinical radiobiology investigations. Despite advances in preclinical dose planning, delivery of highly heterogeneous dose distributions is constrained by the fixed collimation systems and large x‐ray focal spot common in small animal radiotherapy systems. This work proposes a dual focal spot dose optimization and delivery method with a large x‐ray focal spot used to deliver homogeneous dose regions and a small focal spot to paint spatially heterogeneous dose regions.Methods:Two‐dimensional dose kernels were measured for a 1 mm circular collimator with radiochromic film at 10 mm depth in a solid water phantom for the small and large x‐ray focal spots on a recently developed small animal microirradiator. These kernels were used in an optimization framework which segmented a desired dose distribution into low‐ and high‐spatial frequency regions for delivery by the large and small focal spot, respectively. For each region, the method determined an optimal set of stage positions and beam‐on times. The method was demonstrated by optimizing a bullseye pattern consisting of 0.75 mm radius circular target and 0.5 and 1.0 mm wide rings alternating between 0 and 2 Gy.Results:Compared to a large focal spot technique, the dual focal spot technique improved the optimized dose distribution: 69.2% of the optimized dose was within 0.5 Gy of the intended dose for the large focal spot, compared to 80.6% for the dual focal spot method. The dual focal spot design required 14.0 minutes of optimization, and will require 178.3 minutes for automated delivery.Conclusion:The dual focal spot optimization and delivery framework is a novel option for delivering conformal and heterogeneous dose distributions at the preclinical level and provides a new experimental option for unique radiobiological investigations.Funding Support: this work is supported by funding the National Sciences and Engineering Research Council of Canada, and a Mitacs‐accelerate fellowship.Conflict of Interest: Dr. Lindsay and Dr. Jaffray are listed as inventors of the small animal microirradiator described herein. This system has been licensed for commercial development.
WE‐E‐BRE‐12: Tumor Microenvironment Dynamics Following Radiation
Authors: Campos D , Niles D , Adamson E , Torres A , Kissick M , Eliceiri K , Kimple R 
Published: July 2014

Purpose:This work aims to understand the radiation‐induced interplay between tumor oxygenation and metabolic activity. These dynamics can potentially serve as biomarkers in assessing treatment response allowing for patient‐specific adaptive radiotherapy.Methods:Using patient‐derived xenografts of head and neck cancer we assessed tumor oxygenation via fiber‐optic probe monitored hemoglobin saturation and Blood Oxygen Level Dependent (BOLD) MRI. Measurements were taken before and after a 10 Gy dose of radiation. Changes in metabolic activity were measured via Fluorescence Lifetime IMaging (FLIM) with the appropriate controls following a 10 Gy dose of radiation. FLIM can non‐invasively monitor changes in fluorescence in response to the microenvironment including being able to detect free and bound states of the intrinsically fluorescent metabolite NADH (Nicotinamide Adenine Dinucleotide). With this information FLIM can accurately quantify the metabolic state of cells that have been radiated. To model the observed changes, a two‐compartment, source‐sink simulation relating hemoglobin saturation and metabolic activity was performed using MATLAB.Results:Hemoglobin saturation as measured by interstitial probe and BOLD‐MRI decreased by 30% within 15 minutes following radiation. FLIM demonstrated a decrease in the mean fluorescence lifetime of NADH by 100 ps following 10 Gy indicating a shift towards glycolytic pathways. Simulation of radiation‐induced alterations in tumor oxygenation demonstrated that these changes can be the result of changes in either vasculature or metabolic activity.Conclusion:Radiation induces significant changes in hemoglobin saturation and metabolic activity. These alterations occur on time scales approximately the duration of common radiation treatments. Further understanding these dynamics has important implications with regard to improvement of therapy and biomarkers of treatment response.
WE‐E‐17A‐03: FDG‐PET‐Based Radiomics to Predict Local Control and Survival Following Radiotherapy
Authors: Oh J , Apte A , Folkerts M , Kohutek Z , Wu A , Rimmer A , Lee N , Deasy J 
Published: July 2014

Purpose:An exploding field in cancer research is “radiomics,” based on the hypothesis that there is statistical (hidden) information in medical images that is prognostic or predictive of outcomes. Our group has developed an efficient pipeline to extract and analyze quantitative image features from medical images as related to outcomes or diagnosis. In this work, we summarize our previous studies with positron emission tomography (PET) images and show the potential of the use of radiomics for outcomes research.Methods:We analyzed two cancer datasets, each consisting of pre‐radiotherapy‐treatment PET scans: 163 T1‐2N0M0 non‐small cell lung cancer (NSCLC) patients and 174 head and neck (H&N) cancer patients with stage III–IV. The PET scans were converted to Computational Environment for Radiological Research (CERR) format, and CERR was used to generate 24 shape, texture, and intensity‐histogram based image features. Data‐mining and logistic regression methods were then used to model local failure (LF) and overall survival (OS). Unbiased estimates of performance were generated using leave‐one‐out cross‐validation (LOOCV).Results:For predicting LF, the models with biologically equivalent dose (BED) and TLG (metabolic tumor volume (MTV) x SUVmean) in NSCLC, and skewness and MTV in H&N, achieved the best performance with AUC=0.818 (p<0.0001) and AUC=0.826 (p=0.0002), respectively. For predicting OS, the models with kurtosis and volume in NSCLC and SUVmax and homogeneity in H&N achieved the best performance with AUC=0.706 (p<0.0001) and AUC=0.656 (p=0.0003), respectively. On LOOCV, all these models retained significant predictive power. Interestingly, MTV was highly correlated with LF in both sites.Conclusion:PET‐based imaged features are promising tools for improving treatment management decision making. Much more research is needed to identify optimal radiomics metrics and to correlate imaging phenotype with other clinical or genomic information.