bluuebunny/crossref_metadata_2025_split huggingface dataset:
TU‐C‐BRD‐05: Carbon Nanotube Field Emission Based Imaging and Irradiation Technology Development for Basic Cancer Research
Authors: Chang S , Zhou O 
Published: April 2010

Caron nanotube (CNT) field emission is an emerging nanotechnology enabling the development of novel x‐ray imaging and radiation delivery systems for basic cancer research and clinical application. In this presentation a brief overview of the CNT nanotechnology and its recent development in the application of micro‐CT imaging, micro‐RT, cellular and tissue level microbeam irradiation will be presented.The CNT field emission technology based systems have clear potential advantages over conventional imaging and irradiation systems based on thermionic emission. Micro‐RT and micro‐CT systems that are based on thermionic emission technology commonly rely on a single radiation source and the imaging and irradiation depend on source rotation and thus can lead to poor temporal resolution for small animal research. The CNT field emission based systems employ individually addressable multipixel cathode array radiation sources and thus are capable of high temporal resolution, static (no rotation) imaging and electronically shaping a small radiation field and its intensity map. In clinical application, a CNT field emission based imaging and irradiation system can also improve treatment/imaging efficiency and improve patient throughput.Learning Objectives:1. Understand basic principle of carbon nanotube field emission technology and its potential in imaging and irradiation technology development for cancer research and clinical application2. Understand current status of the CNT field emission based imaging and irradiation technology development3. Understand the basic achievements and challenges in the technology development.The research projects are supported grants from NIH R21 CA118351, U54‐CA119343‐01, R21CA128510, NC Biotechnology Center MRG‐1111, R33EB004204, and XintekConflict of interest: Zhou is the Chairman of Xintek, Inc. and a board member of XinRay Systems, LLC
TU‐C‐BRB‐01: Junior Investigator Winner: Outcome Prediction of Cervical Cancer: Kinetic Model of Tumor Regression During Radiation Therapy
Authors: Huang Z , Mayr N , Yuh W , Lo S , Montebello J , Lu L , Li K , Zhang H , Gupta N , Wang J 
Published: April 2010

Purpose: A kinetic model on describing tumor response to radiation therapy (RT) was developed to analyze the tumor regression data and predict the RT outcome for cervical cancer. Methods and Materials: Eighty patients of cervical cancer (stages IB2‐IVA) completed four sequential magnetic resonance imaging (MRI) scans before, during and after RT. The median follow‐up time is 5.5 years (range 0.2–9.4 years). A kinetic model incorporating three major effects: radiation cell killing, dead‐cell resolving, and tumor repopulation, was developed to fit the volumetric regression data measured by serial MRI scans. The derived radiobiological parameters were correlated with long‐term clinical outcome.Results: The tumor regression kinetics was significantly different for the two outcome groups: local control vs. local failure. The tumor regression rate and model parameters correlated significantly with the treatment outcome (p<0.001), with a median 2‐Gy surviving fraction (S2) of 0.65 and a median half‐time of dead‐cell resolving (T1/2) of 7.9 days for locally controlled tumors, vs. S2=0.70 and T1/2=18 days for locally recurrent tumors. The 6‐year local tumor control rate was 87% vs. 54% for patients with S2<0.70 vs. ⩾0.70 (p=0.001), and 95% vs. 57% for patients with T1/2 <22 days vs. ⩾22 days (p<0.001), respectively. Similarly the 6‐year disease‐free survival was 73% vs. 41% for the patients with S2<0.70 vs. ⩾0.70 (p=0.025), and 87% vs. 52% for patients with T1/2<22 days vs. ⩾22 days (p=0.002), respectively. Conclusion: The kinetic model well fits the temporal change of 3D tumor volume measured by serial MRI. Our data demonstrated that the locally recurrent tumors were not only radioresistant, but also had slow dead‐cell resolving probably due to the poor tumor microcirculation. This approach shows promise for volume‐based tumor response modeling and potential to refine outcome prediction.
TU‐C‐304A‐10: Effects of KVp On Dose‐Normalized Contrast‐To‐Noise Ratio Relevant to Pediatric CT
Authors: Feng W , MacDougall R , Schultz C , Drake D , Bakalyar D 
Published: April 2010

Purpose: The purpose of this research was to systematically explore the change in contrast‐noise ratio (CNR) for a variety of substances as a function of kV in CT examinations for small body habitus under the condition of constant dose. Method and Materials: The head module of a Gammex RMI 461A Head/Body phantom (constructed from solid water) was suspended from the end of the table of a Philips Brilliance 6‐slice CT scanner. An ion chamber introduced into the center of the phantom was used to adjust the mAs at kVp values of 90, 120 and 140 so that the exposure at the center was the same at all kVp values. Fifteen materials were tested at the center of the phantom for each of the kVp values with the CT number mean and standard deviation (SD) measured for each of the resulting 45 scans. A control area in the solid water was also tested for each scan using an identical ROI. Related tests were performed on all samples at once using other scanners.Results: For all 45 scans, the SD was independent of kVp demonstrating that the noise was a function of dose only and not kV. For high density materials, lowering the kV improved the CNR in a predictable way. For materials with CT numbers not far from water, however, in some cases the CNR became worse with decreasing kVp while in others, the CNR improved. Conclusion: While lowering the kVp vs. lowering the mAs in small body habitus may result in an improved CNR, it should not be assumed that this is always the case. Dose reduction strategies for particular situations may benefit more by reducing the beam intensity and keeping the kV high.
TU‐E‐210A‐04: Dual Energy CT Image Reconstruction Algorithms and Performance
Authors: O'Sullivan JA 
Published: April 2010

Dual energy X‐ray computed tomography (CT) is becoming more important, in part due to the availability of multi‐row scanners that collect data using two source energy spectra. An X‐ray source emits a spectrum of energies for each setting of the source. The energy dependence of Beer's Law leads to the relationship between the overall attenuation function and the mean measured data; the statistics of the data given the mean data determine a more accurate model. In many approaches, linear approximations to these inherently nonlinear phenomena are used to derive algorithms.The data can be used to form two attenuation images that can be interpreted as coefficients corresponding to component attenuation spectra; given additional constraints such as nonnegative attenuation and a sum of fractional contributions equal to one, a third attenuation image can be recovered. Component attenuation spectra may correspond to physical processes (photoelectric and Compton effects), to known materials (for example, fat and bone), or to spectra that nearly span the set of spectra (for example, computed using a singular value decomposition).Three classes of dual‐energy algorithms are discussed: prereconstruction, postreconstruction, and statistical iterative reconstruction (SIR), the latter recovering multiple images simultaneously using all data. The tradeoffs in performance of these algorithms are discussed. Analytical techniques for bounding achievable performance based on data models may be used in system analysis and design. Performance in actual systems may vary somewhat from the analytical predictions, due to inevitable differences between the model used for computing reconstructions and the clinical devices. This discrepancy in actual and predicted performance can be quantified in many situations. The approaches described extend in a straightforward fashion to data acquisitions using three or more energy bands.Learning Objectives:1. Understand the assumptions underlying dual‐energy image reconstructions.2. Understand the centrality of the nonlinear data model in dual‐energy CT.3. Understand the different methods that may be used to compute the image reconstructions.4. Understand the role of image performance prediction and limitations of performance prediction.
WE‐SAM‐BRB‐01: Image Processing in Radiation Therapy: A Play in Three Acts
Authors: Kessler M , Siewerdsen J , Sonke JJ 
Published: April 2010

Acquisition, processing and analysis of medical image data are now fundamental parts of patient management in radiation therapy. Image data are used to aid diagnosis and staging, to guide treatment planning and delivery and to help monitor the patient during and after therapy. Most radiotherapy departments have dedicated CT scanners, some with 4D capabilities. Many departments also have or are contemplating dedicated MR and PET/CT scanners. More imaging devices are also appearing in the treatment room, with in‐room, on‐board and integrated imaging devices becoming commonplace. The availability of hybrid MR scanner/treatment units is not far off.Naturally, each imaging modality provides both benefits and challenges towards supporting and improving the radiotherapy process. In order to leverage the information in the various imaging studies, effective processing tools are needed to extract useful information and to combine and present it in a way that promotes a clear and efficient workflow. There are several classes of these tools including image enhancement, visualization, segmentation, registration and quantification. These tools may be used individually or in combination at many points in the radiotherapy process with the overall goal to create a more complete and accurate model of the patient so that an effective course of therapy can be devised and carried out.This course provides an overview of the different imaging modalities and procedures used in radiotherapy and highlights the benefits and challenges of each. A detailed description of the various image processing tools used to extract, combine and analyze the information from different imaging studies is also presented. Finally, the effective use of these tools at each step of the radiotherapy process is described and elucidated using numerous clinical examples.Learning Objectives:1. Act 1 Understand the benefits and challenges of the various imaging modalities used in radiation therapy.2. Act 2 Understand the mechanics of the different classes of image processing tools using in radiotherapy.3. Act 3 Understand how image processing tools are used to support and improve the radiotherapy process.
WE‐SAM‐304A‐01: PET/CT Technology Update, Quality Assurance and Applications
Authors: Mawlawi O 
Published: April 2010

In the past few years, positron emission tomography/computed tomography (PET/CT) imaging has increasingly been used for the diagnosis, staging, and restaging of malignant diseases. The success of this emerging modality has primarily been due to its ability to combine the advantages of both PET and CT imaging while minimizing their separate weaknesses. One of the main advantages of PET/CT imaging is its ability to generate functional images depicting the biodistribution of radioactive compounds that are correlated with anatomical landmarks thereby increasing the physicians' confidence in image interpretation and improving patient management.The aim of this lecture is to provide an overview of the basic physics principles of PET/CT imaging as well as the advantages and drawbacks of using CT for attenuation correction of PET data. In addition, the lecture will cover the latest in design specifics of commercially available PET/CT scanners from different manufacturers as well as review PET/CT quality control and assurance techniques.Learning Objectives:1. To learn the basic physics principles of PET/CT imaging2. To understand the advantages and drawbacks of using CT for attenuation correction of PET images.3. Become familiar with design specifics of commercially available PET/CT scanners.4. Learn quality control and assurance techniques for PET/CT imaging
WE‐A‐BRD‐01: Locating and Targeting Moving Tumors with Radiation Beams
Authors: Keall P , Cho B , Dieterich S , Poulsen P , Ruan D , Sawant A , Suh Y 
Published: April 2010

The current climate of rapid technological evolution is reflected in newer and better methods to modulate and direct radiation beams for cancer therapy. This Continuing Education lecture focuses on one aspect of this evolution, locating and targeting moving tumors. The two processes — locating and targeting tumors— are somewhat independent and in principle different implementations of these processes can be interchanged. Advanced localization and targeting methods have an impact on treatment planning, and also present new challenges for quality assurance (QA), that of verifying real‐time delivery. Some methods to locate and target moving tumors with radiation beams are currently FDA approved for clinical use — and this availability and implementation will increase with time. Extensions of current capabilities will be the integration of higher order dimensionality into the estimate of the patient pose and real‐time reoptimization and adaption of delivery to the dynamically changing anatomy of cancer patients.Learning Objectives:1. To describe the technology available to determine real‐time target position2. To review the systems for real‐time target‐beam alignment3. To discuss the practical considerations of real‐time target tracking systemsResearch sponsored by Accuray, Calypso, Cyberheart, GE, NIH/NCI, Philips and Varian.
WE‐A‐210A‐01: Fluoroscopic Imaging Equipment: Guidelines for Detector Input Dose Settings and Image Optimization
Authors: Rauch P 
Published: April 2010

Modern fluoroscopy imaging equipment is designed to simultaneously monitor x‐ray generator parameters, detector exposure rate, contrast‐to‐noise ratio, and x‐ray tube loading. Under programmed control, fluoroscopy systems automatically make adjustments to the parameters controlling x‐ray production, beam filtration, detector signal output, digital image processing, and image presentation. Any means intended to reduce patient dose should be implemented in a way that preserves image quality.For the clinical medical physicist, optimization of fluoroscopic equipment performance begins with an understanding of the variable system parameters, and the identification of the trigger points for changes in these parameters. Secondly, an understanding of how system parameters affect each other, affect image quality, and affect patient dose can lead to better choices in how the system should be set up for specific applications.A necessary requirement is an understanding of what detector input dose one should expect with an image intensifier fluoroscopy system, and how the detector dose should change when a flat panel detector is utilized. It is also necessary to understand how operational settings on the equipment can obviate superior detector performance as determined by detector type and metrics. This presentation will use imaging examples from installed systems to explore these issues. Also, a clear, concise guideline for determining the appropriate fluoroscopy detector input dose rate for both image intensifier and flat panel detectors will be presented.Learning Objectives:1. Provide an understanding of modern fluoroscopic imaging system component design and functionality2. Determine the appropriate fluoroscopy detector input dose rate for image intensifier and flat panel detectors3. Describe specific ways in which equipment settings can enhance or detract from optimum performance.
WE‐C‐BRB‐01: In Vivo Measurement of Proton Stopping Power Ratios in Patients Using Dual Energy Computed Tomography
Authors: Yang M , Virshup G , Clayton J , Zhu X , Mohan R , Dong L 
Published: April 2010

Purpose: To introduce a new method based on dual‐energy CT (DECT) for determining patient‐specific proton stopping power ratios (SPRs) required for accurate computation of proton dose distributions. Accurate determination of SPRs requires atomic number information, which cannot be deduced from conventional CT scans. Method and Materials: We have developed a two‐parameter model to extract electron density ratios (EDRs) and effective atomic number (EANs) from two CT scans acquired at different energies. Based on an empirical relationship we discovered between the known SPRs and EANs of human biological tissues of standard density and elemental compositions published in ICRU 44 and ICRP 23, we can estimate the SPR of any human biological tissue from its EDR and EAN values obtained from DECT scans. To validate this approach and compare it to existing practice, we introduced variations to the density and compositions of standard biological tissues to simulate unknown biological tissues. SPRs thus estimated using the DECT method are compared with their theoretical SPRs calculated using the Bethe‐Bloch equation and a clinical procedure introduced by Schneider et al. at Paul Scherrer Institute (the PSI method). Results: The accuracy of SPRs of standard human biological tissues estimated using the DECT method are substantially improved compared to those estimated using the PSI method: the maximum absolute (MAX) error and the root‐mean‐square (RMS) error are reduced from 3.19% and 0.89% to 1.10% and 0.29%, respectively. The DECT method is even more effective in SPR calculation when small perturbations were introduced in the standard tissue density and compositions: the MAX and RMS errors were reduced from 8.70% and 3.31% to 1.65% and 0.53%, respectively. Conclusion: The DECT approach is an effective method for accurate determination of voxel‐by‐voxel effective atomic numbers and SPRs of biological tissues.Conflict of Interest: Research sponsored, in part, by Varian Medical Systems, Inc.
WE‐C‐BRC‐02: Combined Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE‐MRI) and Magnetic Resonance Thermal Imaging (MRTI) for Optimal Hyperthermia Treatment of Advanced Extremity Sarcomas: Fifteen Patients Update
Authors: Craciunescu O , MacFall J , Soher B , Stauffer P , Maccarini P , Jones E , Larrier N , Wong T , Carroll M , Dewhirst M , Vujaskovic Z 
Published: April 2010

Purpose: To deliver optimal hyperthermia (HT) treatments for patients with advanced extremity sarcomas using DCE‐MRI and MRTI Method and Materials: Patients were treated on a protocol using radiotherapy consisting of 45 Gy and once a week HT for 5 weeks in a setting that allows the use of a 1.5 T GE magnet for imaging. Pre‐ and post first HT treatment DCE‐MR images were acquired and analyzed with software from iCAD Inc. (Nashua, NH) based on a full time point pharmacokinetics (PK) analysis that measures tumor's permeability (Ktrans) and extracellular volume fraction (Ve). Multi‐slice temperature rise images were obtained using the proton resonance frequency shift technique during heating in a 140 MHz phased array HT applicator and compared to invasive temperature measurements. Thermal dose metrics were calculated and correlated with response and with the PK parameters. Results: Fifteen patients were enrolled on this protocol; ten patients were heated. Permeability maps derived from DCE‐MR images were used to guide the placement of the invasive catheter to span regions varying from high to low perfusion. The MRTI images were used to steer the power, with the intent of heating the tumor uniformly while maintaining surrounding normal tissue at lower temperatures. From the evaluable HT treatments, we achieved excellent correlation (ΔT<1°C) between the MRTI and invasive measurements. As a trend, patients that were either pathological complete or partial responders had a decrease in Ktrans. The Ve parameter showed no clear trend with pathological response or % necrosis. As expected, tumors that were more vascularized (higher Ktrans) heated less than tumors with a high degree of necrosis or fluid pockets. Conclusion: DCE‐MRI coupled with MRTI provides information on tumor environment that can improve planning, delivery, and evaluation of HT treatments.Supported by a grant from the NCI CA42745.
WE‐D‐210A‐04: Novel PET Probes to Image the Immune System and Cancer — From Discovery to Clinical Applications
Authors: Radu C 
Published: April 2010

Monitoring immune function using molecular imaging could significantly impact the diagnosis and treatment evaluation of immunological disorders and therapeutic immune responses. Positron Emission Tomography (PET) is a molecular imaging modality with applications in cancer and other diseases. PET studies of immune function have been limited by a lack of specialized probes. We identified [18F]FAC (1‐(2′‐deoxy‐2′‐[18F]fluoroarabinofuranosyl) cytosine) by differential screening as a new PET probe for the deoxyribonucleotide salvage pathway. [18F]FAC PET enabled visualization of lymphoid organs and was sensitive to localized immune activation in a mouse model of anti‐tumor immunity. [18F]FAC microPET also detected early changes in lymphoid mass in systemic autoimmunity and allowed evaluation of immunosuppressive therapy. We have also developed a series of [18F]FAC analogs with improved pharmacokinetic properties. Data in animal models and preliminary studies in humans support the use of [18F]FAC and its analogs for immune monitoring by PET and suggest a wide range of clinical applications in immune disorders and in certain types of cancer.Research sponsored in part by Sofie Biosciences through a UC Discovery grant.
WE‐D‐213A‐02: Establishing a Stereotactic Body Radiation Therapy (SBRT) Clinical Program, Part 2: Clinical and Radiobiological Considerations
Authors: Read P , Kavanagh B 
Published: April 2010

Stereotactic Body Radiation Therapy (SBRT) has emerged as an important form of cancer therapy with broad application across a spectrum of tumor types in the primary and metastatic settings. The capability of safely administering a very high dose of therapeutic radiation to discrete extracranial tumor sites has raised new questions about the radiobiology of high dose per fraction treatment. Accumulating clinical experiences are yielding new insights into practical aspects of tumor and normal tissue responses to high dose per fraction treatment.The current practice of SBRT has evolved to some extent from knowledge gained from principles learned from the practice of cranial stereotactic radiosurgery (SRS). For the integration of SBRT into clinical practice, medical physicists and radiation oncologists are advised to collaborate closely to establish clear guidelines for normal tissue dose constraints and tumor dose prescription practices that are suitable to their own clinical environment. Published literature relevant to this objective will be discussed. A consistent strategy for contouring sensitive organs is encouraged. The technological challenges introduced by the high dose and high precision paradigm of SBRT are presented and the vital relationship between physicist and physician in this context cannot be overemphasized.The radiobiological issues that have been parsed by this new paradigm of treatment will be explored, including understanding of conventional, hypofractionated and single dose treatments, radiobiological modeling, and the concepts of equivalent doses. Future trends in SBRT will be discussed. Clinical outcomes after SBRT in a variety of setting will be summarized.Learning Objectives:1. Review and understand the major issues related to the use SBRT for, including key strategies for uniform contouring and determination of organ tolerances.2. Review and understand the common clinically observed normal tissue responses to SBRT and the inferences to be drawn regarding the practical radiobiology of high dose per fraction therapy3. Discuss these new paradigms of fractionation as they relate to conventional regimes, including hypofractionation and single dose treatments and their radiobiological threshold effects.4. Review potential future application of SBRT