bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐EF‐207‐01: FEATURED PRESENTATION and BEST IN PHYSICS (IMAGING): Task‐Driven Imaging for Cone‐Beam CT in Interventional Guidance
Authors: Gang G , Stayman J , Ouadah S , Ehtiati T , Siewerdsen J 
Published: June 2015

Purpose:This work introduces a task‐driven imaging framework that utilizes a patient‐specific anatomical model, mathematical definition of the imaging task, and a model of the imaging system to prospectively design acquisition and reconstruction techniques that maximize task‐based imaging performance. Utility of the framework is demonstrated in the joint optimization of tube current modulation and view‐dependent reconstruction kernel in filtered‐backprojection reconstruction and non‐circular orbit design in model‐based reconstruction.Methods:The system model is based on a cascaded systems analysis of cone‐beam CT capable of predicting the spatially varying noise and resolution characteristics as a function of the anatomical model and a wide range of imaging parameters. Detectability index for a non‐prewhitening observer model is used as the objective function in a task‐driven optimization. The combination of tube current and reconstruction kernel modulation profiles were identified through an alternating optimization algorithm where tube current was updated analytically followed by a gradient‐based optimization of reconstruction kernel. The non‐circular orbit is first parameterized as a linear combination of bases functions and the coefficients were then optimized using an evolutionary algorithm. The task‐driven strategy was compared with conventional acquisitions without modulation, using automatic exposure control, and in a circular orbit.Results:The task‐driven strategy outperformed conventional techniques in all tasks investigated, improving the detectability of a spherical lesion detection task by an average of 50% in the interior of a pelvis phantom. The non‐circular orbit design successfully mitigated photon starvation effects arising from a dense embolization coil in a head phantom, improving the conspicuity of an intracranial hemorrhage proximal to the coil.Conclusion:The task‐driven imaging framework leverages a knowledge of the imaging task within a patient‐specific anatomical model to optimize image acquisition and reconstruction techniques, thereby improving imaging performance beyond that achievable with conventional approaches.2R01‐CA‐112163; R01‐EB‐017226; U01‐EB‐018758; Siemens Healthcare (Forcheim, Germany)
WE‐EF‐207‐10: Striped Ratio Grids: A New Concept for Scatter Estimation
Authors: Hsieh S 
Published: June 2015

Purpose:To propose a new method for estimating scatter in x‐ray imaging. We propose the “striped ratio grid,” an anti‐scatter grid with alternating stripes of high scatter rejection (attained, for example, by high grid ratio) and low scatter rejection. To minimize artifacts, stripes are oriented parallel to the direction of the ramp filter. Signal discontinuities at the boundaries between stripes provide information on local scatter content, although these discontinuities are contaminated by variation in primary radiation.Methods:We emulated a striped ratio grid by imaging phantoms with two sequential CT scans, one with and one without a conventional grid, and processed them together to mimic a striped ratio grid. Two phantoms were scanned with the emulated striped ratio grid and compared with a conventional anti‐scatter grid and a fan‐beam acquisition, which served as ground truth. A nonlinear image processing algorithm was developed to mitigate the problem of primary variation.Results:The emulated striped ratio grid reduced scatter more effectively than the conventional grid alone. Contrast is thereby improved in projection imaging. In CT imaging, cupping is markedly reduced. Artifacts introduced by the striped ratio grid appear to be minimal.Conclusion:Striped ratio grids could be a simple and effective evolution of conventional anti‐scatter grids. Unlike several other approaches currently under investigation for scatter management, striped ratio grids require minimal computation, little new hardware (at least for systems which already use removable grids) and impose few assumptions on the nature of the object being scanned.
WE‐EF‐210‐00: Advances in Ultrasound Imaging Technology
Authors: Zagzebski James 
Published: June 2015

Recent advances in ultrasound‐related technologies have had a significant impact on enhancing image quality as well as offering new approaches for quantitative ultrasonic imaging and therapeutic applications. The presentations associated with this session will provide an overview of advances in ultrasound image formation, the development of using nanoparticles for therapeutic ultrasound applications, as well as approaches for assessing the intrinsic viscoelastic properties of tissue and methods for monitoring tissue response to therapy.Learning Objectives:

Develop a general understanding of new technologies associated with enhanced ultrasound image formation and volume imaging.
Develop an understanding of new ultrasound‐based technologies for quantitative assessment of intrinsic tissue properties.
Develop an understanding of novel approaches for ultrasound‐mediated non‐invasive therapeutic applications.
Dr. Rao is an employee of Siemens Ultrasound
WE‐EF‐210‐04: Viscoelastic Response (VisR) Ultrasound for Noninvasively Assessing the Viscoelastic Properties of Tissue
Authors: Gallippi C. 
Published: June 2015

Recent advances in ultrasound‐related technologies have had a significant impact on enhancing image quality as well as offering new approaches for quantitative ultrasonic imaging and therapeutic applications. The presentations associated with this session will provide an overview of advances in ultrasound image formation, the development of using nanoparticles for therapeutic ultrasound applications, as well as approaches for assessing the intrinsic viscoelastic properties of tissue and methods for monitoring tissue response to therapy.Learning Objectives:

Develop a general understanding of new technologies associated with enhanced ultrasound image formation and volume imaging.
Develop an understanding of new ultrasound‐based technologies for quantitative assessment of intrinsic tissue properties.
Develop an understanding of novel approaches for ultrasound‐mediated non‐invasive therapeutic applications.
Dr. Rao is an employee of Siemens Ultrasound
WE‐F‐BRB‐01: The Power of Ontologies and Standardized Terminologies for Capturing Clinical Knowledge
Authors: Gabriel P. 
Published: June 2015

Advancements in informatics in radiotherapy are opening up opportunities to improve our ability to assess treatment plans. Models on individualizing patient dose constraints from prior patient data and shape relationships have been extensively researched and are now making their way into commercial products. New developments in knowledge based treatment planning involve understanding the impact of the radiation dosimetry on the patient. Akin to radiobiology models that have driven intensity modulated radiotherapy optimization, toxicity and outcome predictions based on treatment plans and prior patient experiences may be the next step in knowledge based planning. In order to realize these predictions, it is necessary to understand how the clinical information can be captured, structured and organized with ontologies and databases designed for recall. Large databases containing radiation dosimetry and outcomes present the opportunity to evaluate treatment plans against predictions of toxicity and disease response. Such evaluations can be based on dose volume histogram or even the full 3‐dimensional dose distribution and its relation to the critical anatomy.This session will provide an understanding of ontologies and standard terminologies used to capture clinical knowledge into structured databases; How data can be organized and accessed to utilize the knowledge in planning; and examples of research and clinical efforts to incorporate that clinical knowledge into planning for improved care for our patients.Learning Objectives:

Understand the role of standard terminologies, ontologies and data organization in oncology
Understand methods to capture clinical toxicity and outcomes in a clinical setting
Understand opportunities to learn from clinical data and its application to treatment planning
Todd McNutt receives funding from Philips, Elekta and Toshiba for some of the work presented
WE‐F‐BRB‐03: Inclusion of Data‐Driven Risk Predictions in Radiation Treatment Planning in the Context of a Local Level Learning Health System
Authors: McNutt T. 
Published: June 2015

Advancements in informatics in radiotherapy are opening up opportunities to improve our ability to assess treatment plans. Models on individualizing patient dose constraints from prior patient data and shape relationships have been extensively researched and are now making their way into commercial products. New developments in knowledge based treatment planning involve understanding the impact of the radiation dosimetry on the patient. Akin to radiobiology models that have driven intensity modulated radiotherapy optimization, toxicity and outcome predictions based on treatment plans and prior patient experiences may be the next step in knowledge based planning. In order to realize these predictions, it is necessary to understand how the clinical information can be captured, structured and organized with ontologies and databases designed for recall. Large databases containing radiation dosimetry and outcomes present the opportunity to evaluate treatment plans against predictions of toxicity and disease response. Such evaluations can be based on dose volume histogram or even the full 3‐dimensional dose distribution and its relation to the critical anatomy.This session will provide an understanding of ontologies and standard terminologies used to capture clinical knowledge into structured databases; How data can be organized and accessed to utilize the knowledge in planning; and examples of research and clinical efforts to incorporate that clinical knowledge into planning for improved care for our patients.Learning Objectives:

Understand the role of standard terminologies, ontologies and data organization in oncology
Understand methods to capture clinical toxicity and outcomes in a clinical setting
Understand opportunities to learn from clinical data and its application to treatment planning
Todd McNutt receives funding from Philips, Elekta and Toshiba for some of the work presented
WE‐G‐304‐00: It Can't Happen to Me! ‐ My Position Has Been Terminated, Now What?
Authors: Starkschall George 
Published: June 2015

In the past few years, several high‐profile medical physicists found their positions terminated. It is a fact that no medical physics job is a sinecure, and that individuals can be terminated through no fault of their own. Medical physicists need to be prepared for such an occurrence. Termination provisions in an employment contract, whether individually negotiated or as part of an employee manual, are important, and also generally overlooked when one is going into a new job. Coupled with the fact that most states are “at‐will,” that makes for a tough position for any physicist who finds his/her position terminated.In this course, a medical physicist who is also a practicing attorney will start the discussion with a description of the various types of employment situations and employment agreements. This will be followed by two high‐profile medical physicists who had their positions terminated in recent years, who will describe their experiences, including answering such questions asHow much time were you given before termination was effective?Did you have any foreshadowing of what was coming?How did you deal with the termination?Given hindsight, what would you have done differently to mitigate the effects of your termination?During job interviews, are there ways to open closets to find the skeletons?What advice would you give medical physicists if faced with a similar situation?What can you negotiate in a termination agreement?What kinds of termination agreements could be presented?The symposium will conclude with a panel discussion.Learning Objectives:

Identify the various types of employment contracts with an emphasis on termination provisions.
Recognize the implications of non‐compete clauses in employment contracts.
Recognize the possibility of termination of employment.
Identify ways to recognize possibly poor employment situations
Identify steps that one could take to mitigate the effects of termination.
WE‐G‐BRD‐06: Volumetric Cine MRI (VC‐MRI) Estimated Based On Prior Knowledge for On‐Board Target Localization
Authors: Harris W , Yin F , Cai J , Zhang Y , Ren L 
Published: June 2015

Purpose:To develop a technique to generate on‐board VC‐MRI using patient prior 4D‐MRI, motion modeling and on‐board 2D‐cine MRI for real‐time 3D target verification of liver and lung radiotherapy.Methods:The end‐expiration phase images of a 4D‐MRI acquired during patient simulation are used as patient prior images. Principal component analysis (PCA) is used to extract 3 major respiratory deformation patterns from the Deformation Field Maps (DFMs) generated between end‐expiration phase and all other phases. On‐board 2D‐cine MRI images are acquired in the axial view. The on‐board VC‐MRI at any instant is considered as a deformation of the prior MRI at the end‐expiration phase. The DFM is represented as a linear combination of the 3 major deformation patterns. The coefficients of the deformation patterns are solved by matching the corresponding 2D slice of the estimated VC‐MRI with the acquired single 2D‐cine MRI. The method was evaluated using both XCAT (a computerized patient model) simulation of lung cancer patients and MRI data from a real liver cancer patient. The 3D‐MRI at every phase except end‐expiration phase was used to simulate the ground‐truth on‐board VC‐MRI at different instances, and the center‐tumor slice was selected to simulate the on‐board 2D‐cine images.Results:Image subtraction of ground truth with estimated on‐board VC‐MRI shows fewer differences than image subtraction of ground truth with prior image. Excellent agreement between profiles was achieved. The normalized cross correlation coefficients between the estimated and ground‐truth in the axial, coronal and sagittal views for each time step were >= 0.982, 0.905, 0.961 for XCAT data and >= 0.998, 0.911, 0.9541 for patient data. For XCAT data, the maximum‐Volume‐Percent‐Difference between ground‐truth and estimated tumor volumes was 1.6% and the maximum‐Center‐of‐Mass‐Shift was 0.9 mm.Conclusion:Preliminary studies demonstrated the feasibility to estimate real‐time VC‐MRI for on‐board target localization before or during radiotherapy treatments.National Institutes of Health Grant No. R01‐CA184173; Varian Medical System
WE‐G‐BRB‐04: Leveraging Innovation to Design Future Clinical Trials
Authors: Michalski J. 
Published: June 2015

Over the past 20 years the NIH has funded individual grants, program projects grants, and clinical trials which have been instrumental in advancing patient care. The ways that each grant mechanism lends itself to the different phases of translating research into clinical practice will be described. Major technological innovations, such as IMRT and proton therapy, have been advanced with R01‐type and P01‐type funding and will be discussed. Similarly, the role of program project grants in identifying and addressing key hypotheses on the potential of 3D conformal therapy, normal tissue‐guided dose escalation and motion management will be described. An overview will be provided regarding how these technological innovations have been applied to multi‐institutional NIH‐sponsored trials. Finally, the panel will discuss regarding which research questions should be funded by the NIH to inspire the next advances in radiation therapy.Learning Objectives:

Understand the different funding mechanisms of the NIH
Learn about research advances that have led to innovation in delivery
Review achievements due to NIH‐funded program project grants in radiotherapy over the past 20 years
Understand example advances achieved with multi‐institutional clinical trials
NIH
WE‐G‐BRA‐08: Failure Modes and Effects Analysis (FMEA) for Gamma Knife Radiosurgery
Authors: Xu Y , Bhatnagar J , Bednarz G , Flickinger J , Arai Y , Vacsulka J , Feng W , Monaco E , Niranjan A , Lunsford L Dade , Huq M Saiful 
Published: June 2015

Purpose:To perform a failure modes and effects analysis (FMEA) study for Gamma Knife (GK) radiosurgery processes at our institution based on our experience with the treatment of more than 13,000 patients.Methods:A team consisting of medical physicists, nurses, radiation oncologists, neurosurgeons at the University of Pittsburgh Medical Center and an external physicist expert was formed for the FMEA study. A process tree and a failure mode table were created for the GK procedures using the Leksell GK Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detection (D) for failure modes were assigned to each failure mode by each professional on a scale from 1 to 10. The risk priority number (RPN) for each failure mode was then calculated (RPN = OxSxD) as the average scores from all data sets collected.Results:The established process tree for GK radiosurgery consists of 10 sub‐processes and 53 steps, including a sub‐process for frame placement and 11 steps that are directly related to the frame‐based nature of the GK radiosurgery. Out of the 86 failure modes identified, 40 failure modes are GK specific, caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the GK helmets and plugs, and the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all radiation therapy techniques. The failure modes with the highest hazard scores are related to imperfect frame adaptor attachment, bad fiducial box assembly, overlooked target areas, inaccurate previous treatment information and excessive patient movement during MRI scan.Conclusion:The implementation of the FMEA approach for Gamma Knife radiosurgery enabled deeper understanding of the overall process among all professionals involved in the care of the patient and helped identify potential weaknesses in the overall process.
WE‐G‐303‐01: Physical Bases for Gold Nanoparticle Applications in Radiation Oncology and X‐Ray Imaging
Authors: Cho S. 
Published: June 2015

Over the last decade, there has been a growing interest in applying nanotechnology to cancer detection, treatment, and treatment monitoring. Advances in nanotechnology have enabled the fabrication of nanoparticles from various materials with different shapes and sizes. Nanoparticles can be accumulated preferentially within tumors by either “passive targeting” through a phenomenon typically known as “enhanced permeability and retention” or “active targeting” in which nanoparticles are conjugated with antibodies or peptides directed against tumor and/or stromal markers. The tumor specificity of nanoparticles in conjunction with their unique physicochemical properties offers many novel strategies for cancer treatment and detection. For example, notable approaches in the radiation oncology setting include the use of gold nanoparticles for radiation response modulation of tumor or normal tissue and thermal ablation or hyperthermia treatment of tumors. Some of these approaches are currently being tested either on humans or on animals and, very likely, will become the clinical reality in the near future. Various computational and experimental techniques have also been applied to address unique research issues associated with nanoparticles and may become the standard tools for future investigations and clinical translations. Therefore, both clinicians and researchers may need to be properly educated about the basic principles as well as the promise of nanoparticle‐based applications with regard to the future of cancer diagnostics and therapeutics.This symposium will familiarize the audience with the potential applications of nanoparticles in oncologic imaging and therapy using specific illustrative examples. The audience will be properly oriented by these illustrative examples to the multiple avenues for collaborative research amongst interdisciplinary teams of physicists, clinicians, engineers, chemists, and biologists in industry and academia.Learning Objectives:

Understand the physical bases of gold nanoparticle applications for radiosensitization and x‐ray fluorescence imaging
Understand the parameters that define gold nanoparticle‐mediated radiosensitization in biological systems
Understand the potential of magnetic nanoparticle characterization of the microenvironment
Understand the various strategies for radiolabeling of nanoparticles and their applications
S.C. and S.K. acknowledge support from MD Anderson Cancer Center, NIH (R01CA155446 and P30CA16672) and DoD (W81XWH‐12‐1‐0198); J.W. acknowledges support from NIH (U54CA151662‐01); W.C. acknowledges support from the University of Wisconsin‐Madison, NIH (R01CA169365, P30CA014520, and T32CA009206), DoD (W81XWH‐11‐1‐0644 and W81XWH‐11‐1‐0648), and ACS (125246‐RSG‐13‐099‐01‐CCE).
WE‐G‐204‐03: Photon‐Counting Hexagonal Pixel Array CdTe Detector: Optimal Resampling to Square Pixels
Authors: Shrestha S , Vedantham S , Karellas A , Bellazzini R , Spandre G , Brez A 
Published: June 2015

Purpose:Detectors with hexagonal pixels require resampling to square pixels for distortion‐free display of acquired images. In this work, the presampling modulation transfer function (MTF) of a hexagonal pixel array photon‐counting CdTe detector for region‐of‐interest fluoroscopy was measured and the optimal square pixel size for resampling was determined.Methods:A 0.65mm thick CdTe Schottky sensor capable of concurrently acquiring up to 3 energy‐windowed images was operated in a single energy‐window mode to include ≥10 KeV photons. The detector had hexagonal pixels with apothem of 30 microns resulting in pixel spacing of 60 and 51.96 microns along the two orthogonal directions. Images of a tungsten edge test device acquired under IEC RQA5 conditions were double Hough transformed to identify the edge and numerically differentiated. The presampling MTF was determined from the finely sampled line spread function that accounted for the hexagonal sampling. The optimal square pixel size was determined in two ways; the square pixel size for which the aperture function evaluated at the Nyquist frequencies along the two orthogonal directions matched that from the hexagonal pixel aperture functions, and the square pixel size for which the mean absolute difference between the square and hexagonal aperture functions was minimized over all frequencies up to the Nyquist limit.Results:Evaluation of the aperture functions over the entire frequency range resulted in square pixel size of 53 microns with less than 2% difference from the hexagonal pixel. Evaluation of the aperture functions at Nyquist frequencies alone resulted in 54 microns square pixels. For the photon‐counting CdTe detector and after resampling to 53 microns square pixels using quadratic interpolation, the presampling MTF at Nyquist frequency of 9.434 cycles/mm along the two directions were 0.501 and 0.507.Conclusion:Hexagonal pixel array photon‐counting CdTe detector after resampling to square pixels provides high‐resolution imaging suitable for fluoroscopy.