bluuebunny/crossref_metadata_2025_split huggingface dataset:
WE‐A‐202‐01: Dose and Image Quality in C‐Arm CT Rotational Angiography
Authors: Fahrig R , Girard‐Hughes E , Ganguly A , Tognolini A , Kothary N 
Published: August 2010

Conebeam CT using C‐arm mounted large area flat panels (FPs) is becoming more commonly used in neuro‐ and body‐interventional suites. The ability to visualize vascular geometry in 3D along with soft tissue during an intervention is providing information that may increase accuracy, shorten procedure time and may even change the course of treatment. However, acquisition of the projection data required for volume imaging requires dose to the patient, and understanding the trade‐offs between acquisition parameters, dose and image quality is critical to the appropriate adoption of this imaging technique.Unlike conventional CT, the beam length in conebeam CT can cover the entire length of the object to be imaged or can be varied with the use of collimation, and the concept of CTDI is not, therefore, the metric of choice for measurement of dose. In addition, most C‐arm conebeam CT systems use a short‐scan (pi plus fan‐angle) acquisition, and the dose distribution within the object is not cylindrically symmetric. Finally, since FP design has been optimized for fluoroscopy, image quality when used for CT must be carefully evaluated.This lecture will describe a dose metric that is appropriate for conebeam CT and allows direct comparison with the CTDIw of conventional CT, and will summarize dose‐image quality trade‐offs. A discussion of measured dose metrics and recently published Monte Carlo‐based Effective Dose calculations for head and body applications will be presented. New results from our ongoing clinical study investigating the overall dose impact of 3D C‐arm CT on body interventions will be summarized. Research sponsored by Siemens AG, Healthcare Sector, by NIH grant R01 HL087917 and by the Lucas Foundation.Learning Objectives:1. Understand how differences in acquisition geometry between conebeam and conventional CT affect dose measurement and dose distribution.2. Understand the necessary dose‐image‐quality trade‐offs when using C‐arm CT in the interventional suite
WE‐SAM‐201B‐01: PET/CT Technology Update, Quality Assurance and Applications
Authors: Mawlawi O 
Published: August 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‐SAM‐201B‐02: SPECT/CT: Basics, Quality Assurance, and Clinical Applications
Authors: Kappadath S C 
Published: August 2010

Single‐photon emission computed tomography (SPECT) together with computed tomography (CT), commonly referred to as SPECT/CT, is rapidly becoming a mainstream imaging modality and creating a new paradigm for SPECT imaging. The ability to contemporaneously acquire electro‐mechanically registered dual‐modality SPECT and CT scans improves the SPECT image quality due to CT‐based attenuation correction and enhances the diagnostic confidence of SPECT by providing a CT‐based anatomical overlay. The utilization of SPECT/CT has been mainly in the field of oncology with applications including: tumor localization, differential diagnosis, staging and response to treatment, pre‐surgical planning, radiation therapy treatment planning, and quantitative SPECT/CT‐based internal radionuclide therapy dosimetry/treatment planning. SPECT/CT is also being utilized for cardiac and skeletal imaging and imaging of other non‐malignant diseases.This lecture will review the physics principles underlying SPECT and SPECT/CT imaging, discuss quality assurance of SPECT/CT systems, and present several examples of the clinical application of SPECT/CT.Learning Objectives:1. To understand the physics principles underlying SPECT/CT image acquisition, processing and reconstruction2. To understand the quality assurance procedures specific to hybrid SPECT/CT system3. To become familiar with clinical applications of SPECT/CT imaging
WE‐C‐204B‐07: Real‐Time MRI for Soft‐Tissue‐Based IGRT of Moving and Deforming Lung Tumors
Authors: Sawant A , Pauly K Butts , Alley M , Vasanawala S , Loo B , Joshi S , Hinkle J , Keall P 
Published: August 2010

Purpose: Integrated MRI+Linacs can potentially provide real‐time soft‐tissue‐based image‐guidance for lung cancer IGRT. Towards this, we investigate guidance strategies using prospective rapid lung MRI coupled with deformable image registration. Method and Materials: All experiments were performed on a 1.5 T MRI scanner, using a 4‐channel cardiac coil, under free‐breathing conditions, without extrinisic contrast. A balanced steady‐state free precession (b‐SSFP) imaging sequence was optimized for prospective imaging and reconstruction. Two lung cancer patients (Pt#l: 4 cm tumor, right lower lobe, Pt#2: 6 cm tumor, left upper lobe) were imaged. A viscous fluid‐flow‐based deformable registration was applied to each MRI time series in order to determine motion trajectories of voxels within the field of view. These trajectories were used to characterize:(i) motion of the tumor centroid.(ii) relative trajectories of the tumor centroid and the diaphragmrelative trajectories of different points on the tumor — characterizing tumor rotation/deformation.Results: The modified b‐SSFP sequence yielded acquisition times of ∼0.16s and ∼1.5s for 2D and 3D acquisition, respectively.Tumor trajectory analysis:(i) significant cycle‐to‐cycle variation in tumor motion was observed in both patients(ii) For Pt#l, the tumor centroid showed good correlation with diaphragmatic motion. For Pt#2, this correlation was relatively poor(iii) Pt#l did not exhibit significant tumor rotation/deformation. In Pt.#2, the trajectories of two points on the tumor showed maximum deviations of ∼8 mm (superior‐inferior) and 3.4 mm (anterior‐posterior), indicating non‐negligible rotation/deformation likely due to the influence of the adjacent cardiac wall.Conclusion: To our knowledge, this is the first demonstration of MRI for real‐time imaging of lung cancer. The incorporation of these strategies into MRI+Linacs offers image‐guidance capabilities that are not possible using current techniques: (i) soft‐tissue‐based rather than surrogate‐based monitoring (ii) no fiducial implantation or imaging dose (iii) arbitrary slice selection and (iv) ability to monitor complex motion.
WE‐C‐201C‐01: Perspective on the Developing Modalities for Breast Cancer Imaging
Authors: Karellas A , Vedantham S 
Published: August 2010

Perspective on the Developing Modalities for Breast Cancer Imaging Digital mammography has already become the new standard, replacing screen‐film for breast cancer screening, and for diagnostic work‐up of suspicious findings. New digital imaging technologies may use x‐ray beam characteristics such as tungsten target, silver filtration, and higher kVp; in ways that represent a departure from the long established screen‐film techniques. Representing a logical evolution from two‐dimensional to tomographic and 3D imaging of the breast, breast tomosynthesis and dedicated breast CT are currently investigated as potential replacements or adjuncts to mammography. Mammography (screen‐film or digital) is the single most effective tool for the detection of occult breast cancer with an overall sensitivity as high as about 85% for older women and about 60% or lower for women under the age of 50 years (Rosenberg RD et al. Radiology. 1998;209:511–8, Pisano E et al. N. Engl. J. Med. 2005;353: 1773–83). Attempts to increase sensitivity have included the use of intravenously injected (IV) contrast with digital mammography, tomosynthesis or breast CT but these efforts are in the research stage. With improved hardware and image acquisition techniques, the role of IV contrast injected MRI is gradually expanding as a diagnostic tool, and it is also recommended for screening of high risk patients, due to its high sensitivity. Ultrasound, a well established modality for diagnostic work‐up is evolving from the conventional pulse echo‐based approach to elasticity imaging and ultrasound CT of the breast. Breast scintigraphy with a dedicated camera is now in clinical use and it receives much attention as an adjunct to mammography. Other technologies that include diffuse optical tomography as a stand‐alone modality or in conjunction with MRI or with x‐ray imaging are currently under investigation. We are likely to see an increasing use of alternative imaging approaches in conjunction with mammography, ultrasound and MRI, the three essential modalities for breast cancer detection and for diagnostic work‐up of positive findings.Learning Objectives:1. Appreciate recent advances in the physics and engineering in x‐ray detector technology that contributed to the development of digital mammography, tomosynthesis and dedicated breast CT.2. Recognize the potential quantitative applications and important limitations of the x‐ray based breast imaging modalities.3. Appreciate recent technological developments in current clinical non‐x‐ray modalities such as MRI and ultrasound and their increasingly important role in breast cancer imaging.4. Gain perspective on some emerging modalities such as optical diffuse tomography and their potential role in the detection and diagnosis of breast cancer.
WE‐C‐201C‐02: Advances in Breast MRI: Clinical and Scientific Perspective
Authors: Schnall M 
Published: August 2010

Technology for Breast MRI continues to evolve. A major focus of technical development has been to improve the ability to manage the trade‐off between spatial and temporal resolution in the dynamic contrast enhanced series that is central to breast MRI. Improvement of coil technology, more aggressive use of parallel imaging and the application of novel K — space sampling approaches are all being implemented. In addition, there is significant work related to incorporation of diffusion and spectroscopy data into the breast MRI examination. Finally, there are many academic and commercial groups developing methods of analyzing the multidimensional data acquired as part of an MRI exam to predict diagnosis, characterize cancer and predict treatment response.Research sponsored by Siemens.Learning Objectives:1. Understand methods to improve breast MRI techniques2. Understand the potential role of diffusion and spectroscopy in Breast MRI3. Understand the clinical roles for breast MRI
WE‐C‐201C‐03: Tissue Discrimination Methods in Mammography and Tomosynthesis
Authors: Maidment A D A 
Published: August 2010

Breast imaging is undergoing a revolution towards quantitative tomographic methods. There is active research and development of both dedicated computed tomography, and digital breast tomosynthesis (DBT) or limited‐angle computed tomography. Numerous clinical DBT trials are in progress and two systems are available in Europe. DBT has been shown to have clear value in increasing the conspicuity of lesions by removing overlaying structures present in mammograms.We have recently installed a Hologic Dimensions DBT prototype that has been modified to allow contrast‐enhanced (CE) imaging. Both dual‐energy and temporal CE‐DBT are under investigation. Current research is focused on the development and validation of precise image‐derived metrics (image‐based biomarkers) with physiologically relevant parameters, including treatment response to interventions and clinical outcomes. Our work continues with technique optimization, reconstruction algorithm development, motion correction, and scatter and other signal dependent corrections.With appropriate corrections, CE‐DBT can accurately quantify contrast agent uptake. In previous work, we have shown that CE‐DBT can provide results concordant with dynamic contrast‐enhanced MR in a group of 17 women with known or suspected breast cancer. As such, we believe that CE‐DBT has potential in the same roles as MR. These roles include screening high‐risk populations, staging cancer patients through identification of multifocal, multicentric and contralateral cancer, and assessment of tumor response to neoadjuvant chemotherapy.Finally, there is a revolution in radiographic contrast agents. Taking inspiration from nuclear medicine and optical imaging, we are seeing an increase in research into radiographic contrast agents. These developments are made possible given recent advances in nanoparticles such as designer liposomes, polymersomes and nanospheres. Both blood‐pool and targeted contrast agents are under investigation.Learning Objectives:1. Review the state‐of‐the‐art in DBT system design2. Describe adaptations necessary to perform quantitative CE‐DBT3. Exemplify the clinical applications of CE‐DBTResearch support for this project has been provide in part by XCounter AB, General Electric Health Care, and Hologic Corp, in addition to the Komen for the Cure Foundation, the Department of Defense and the Radiological Society of North America.
WE‐C‐201C‐04: Breast Ultrasound Tomography: Clinical Results at the Karmanos Cancer Institute
Authors: Duric N 
Published: August 2010

Ultrasound is a widely accepted imaging modality that has gained a firm and universal foothold in medical imaging. However, in the case of breast imaging, it serves mainly an adjunctive role. It is not on the front lines of screening and diagnosis because of limitations that include operator dependence, small field of view, and relatively poor image quality compared to other imaging modalities. Research to overcome these limitations began over 30 years ago and has led to the development of ultrasound tomography (UST), an operator independent technique for imaging the breast. Initially, limited computational power and slow data acquisition prevented rapid development of this method. However, in recent years, much progress has been made and UST is now poised to appear on the clinical stage.We report on the performance of an experimental UST prototype at the Karmanos Cancer Institute (KCI) in Detroit, MI. Clinical data were collected under an IRB‐approved protocol from subjects recruited at KCI's Alexander J. Walt Comprehensive Breast Center. The data were used to generate stacks of cross‐sectional reflection images as well as images of the acoustic parameters of sound speed and attenuation. The combination of these images reveals major breast anatomy, including fat, parenchyma, fibrous stroma and masses. Fusion imaging, utilizing thresholding, is shown to visualize mass characteristics and facilitate differentiation of cancer from benign masses. These initial results indicate that operator‐independent whole‐breast imaging and the detection and characterization of cancerous breast masses are feasible using UST techniques. Clinical applications ranging from risk assessment to detection and treatment monitoring are discussed. This presentation will provide an overview of how UST is applied to breast imaging, ranging from theory to clinical use.Learning Objectives:1. Understand how tissue properties can be measured with UST2. Understand the differences between UST and other breast imaging modalities3. Understand the issues related to clinical applications of UST.
WE‐D‐BRB‐05: Dose‐Rate Constant Determination of the Xoft Axxent Electronic Brachytherapy Source Using Spectroscopic Methods
Authors: Pike T , Moga J , Davis S , DeWerd L 
Published: August 2010

Purpose: To use spectroscopic methods to determine the dose‐rate constant (DRC) of the Xoft Axxent® miniature x‐ray source. Method and Materials: Analytical methods have been used to determine the DRC of brachytherapy sources using spectroscopic methods. The method developed at Yale University (Med. Phys. 28, 86–96, 2001) was used with the Axxent® spectrum to calculate the spectroscopic DRC of the Axxent® source. While this method is useful its limitations are pronounced when applied to sources of considerable diameter, such as the Axxent® source. When source size increases the point‐ and line‐source approximations are insufficient for buildup or attenuation calculations. This investigation modifies the original method to account for source diameter and calculates the DRC with measured and Monte Carlo (MC) generated spectra. The Axxent® spectrum was measured at 1 m in air with a low‐energy germanium detector. The spectrum was corrected for detector response and air attenuation to obtain the emitted spectrum in vacuum. Results: The measured spectrum agreed well with the MC generated spectrum. Slight differences in the spectra can be attributed to the energy resolution of the detector. The spectroscopic DRC calculated with the original method produced DRCs that were up to 23% low when compared to the MC calculated DRC. The modified method corrected the attenuation and buildup calculations to account for source diameter and produced DRC that were within 5% of the MC calculated DRC. Conclusion: It was possible to measure and correct the photon spectrum of the Axxent® source. The original method for analytically determining the spectroscopic DRC works well for sources of very small diameter, but is insufficient when applied to sources of considerable diameter. The method must be modified to correct the attenuation and buildup determination in the monoenergetic DRC determination.Conflict of Interest: This research was partially sponsored by Xoft, Inc.
WE‐D‐201C‐01: Advanced Ultrasound Imaging in Interventional Medicine
Authors: Boctor E 
Published: August 2010

Minimally invasive ultrasound‐guided ablative procedures are a promising therapeutic option in many patients with primary liver cancer or isolated hepatic metastases. However, the effectiveness of thermal ablation is currently limited by the lack of precision in the ablation probe placement at the tumor site, and the inability to monitor the progress and document success of the thermal lesion. In this presentation, we will introduce an integrated platform that can utilize 3D ultrasound imaging for both guidance and monitoring of ablative therapies. We will present a rapid US‐based approach to monitor ablative therapy based on elasticity imaging. Also, we will highlight new applications for elasticity imaging in guiding interventions, including multi‐modality registration, and visualization.Learning Objectives:1. Understand the limitations of current ablative monitoring methods.2. Review solutions based on ultrasound technology.3. Understand the potential advantages/disadvantages and future applications of elasticity imaging in monitoring and guiding ablative therapies.
WE‐D‐201C‐03: Ultrasound Modulation of the Blood‐Brain‐Barrier for Targeted Drug Delivery
Authors: McDannold N 
Published: August 2010

The blood‐brain barrier is a primary limitation to the use of many drugs in the central nervous system. This barrier, which normally serves to protect the brain, with few exceptions limits the delivery of only small molecules from the circulation. We have found that when relatively low‐intensity ultrasound bursts are combined with circulating microbubbles (commercially‐available ultrasound contrast agents) that the blood‐brain barrier is temporarily disrupted for a few hours with little or no other effects in the brain. The ultrasound beam can be applied transcranially, resulting in a potential noninvasive means to target drugs to the brain. To date we have demonstrated this technique in small animal models. If this technology can be translated to humans, it could provide new opportunities for the development and use of drugs in the brain.Learning Objectives:1. Learn how ultrasound and microbubbles are applied for blood‐brain barrier disruption2. Identify histological effects of the ultrasound exposures that have been observed in animal studies3. Learn about potential mechanisms that might be involved with the disruption4. Learn how ultrasound can be focused into the brain transcranially and potential methods to guide the procedure.
WE‐D‐201B‐02: Cardiovascular MR Imaging: Recent Improvements in Speed, Resolution, and Contrast
Authors: Riederer S 
Published: August 2010

Within the last decade a number of “parallel acquisition” methods have been developed which allow reduction of acquisition time in MRI. With these, the MRI signal is simultaneously measured by multiple receiver coils, and the redundancy of information allows reduction in the number of necessary measurements. Such methods are particularly well suited to cardiovascular imaging, for which 3D images are generally desired. The practical limit of acceleration is primarily limited by the geometry of the RF receiver coils. MRI systems having coil arrays consisting of several dozen or more elements are becoming commonplace. Of these elements, eight or more might be activated for any one scan. When used in conjunction with other techniques, accelerations of ten‐fold or more can be routinely obtained.Even with acceleration methods, the generation of a high spatial resolution 3D MRI data set still requires scan times on the order of ten seconds or more. However, the unique aspect of MRI compared to other modalities that the data are acquired in Fourier space allows the reconstructed image to appear as if it were acquired in a much smaller time. This is allowed by preferential sampling of the low order spatial frequencies of Fourier space. These advances in parallel acquisition and in effective ordering of Fourier sampling now permit contrast‐enhanced MR angiograms which are markedly superior in spatial and temporal resolution to what they were a decade ago. This thus addresses what is perhaps the principal disadvantage of MRI vs. other modalities for cardiovascular imaging, namely relatively long scan time. The intrinsic advantages of MRI thus can become a greater determinant of its ultimate utilization. These include the 3D nature of the data, the lack of ionizing radiation, the relatively small contrast dose, and the high vascular signal.This presentation will briefly review the physics of the acceleration techniques, discuss the unique synergistic benefits of implementation in cardiovascular imaging, and illustrate the various points with results from multiple in vivo imaging studies.Learning Objectives:1. Understand recently developed physics techniques which have allowed a 10x improvement in the speed of data acquisition for MR cardiovascular imaging2. Understand the impact of improved speed on improvements in image quality.3. Understand some of the relative advantages of MRI vs. other modalities in imaging the cardiovascular system.