bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prevalence and Correlates of Sleep‐Disordered Breathing in Older Men: Osteoporotic Fractures in Men Sleep Study
Authors: Mehra Reena , Stone Katie L. , Blackwell Terri , Ancoli Israel Sonia , Dam Thuy‐Tien L. , Stefanick Marcia L. , Redline Susan ,   for the Osteoporotic Fractures in Men Study
Published: July 2007

OBJECTIVES: To determine the prevalence and distribution of sleep‐disordered breathing and associated correlates in a large cohort of older men using several standardized definitions.DESIGN: Cross‐sectional analyses.SETTING: Six U.S. communities.PARTICIPANTS: Polysomnography was performed on 2,911 participants of the Outcomes of Sleep Disorders in Older Men Sleep Study (mean age±standard deviation 76.38±5.53; body mass index 27.17±3.8 kg/m2).MEASUREMENTS: Three outcomes were assessed: sleep‐disordered breathing (respiratory disturbance index ≥15), obstructive apnea (obstructive apnea index ≥5), and central apnea (central apnea index ≥5).RESULTS: The prevalence of moderate–severe sleep‐disordered breathing was estimated to be 21.4% to 26.4%. Multivariable logistic regression models demonstrated that age (adjusted odds ratio (AOR) per 5‐year increase =1.24, 95% confidence interval (CI)=1.15–1.34), obesity (AOR=2.54, 95% CI=2.09–3.09), Asian versus Caucasian race (AOR=2.14, 95% CI=1.33–3.45), snoring (AOR=2.01, 95% CI=1.62–2.49), sleepiness (AOR=1.41, 95% CI=1.11–1.79), hypertension (AOR=1.26, 95% CI=1.06–1.50), cardiovascular disease (AOR=1.24, 95% CI=1.19–1.29), and heart failure (AOR=1.81, 1.31–2.51) were independently associated with sleep‐disordered breathing; snoring (AOR=2.10, 95% CI=1.67–2.70), age (AOR per 5‐year increase=1.27, 95% CI=1.18–1.38), obesity (AOR=1.48, 95% CI=1.21–1.82), and heart failure (AOR=1.60, 95% CI=1.15–2.24) were associated with obstructive apnea; and age (AOR=1.33, 1.17–1.50) and heart failure (AOR=1.88, 95% CI=1.17–3.04) were associated with central apnea.CONCLUSION: Regardless of definition, a high prevalence of sleep disorders is observed in community‐dwelling older men. Qualitatively similar associations were observed between sleep disorders and snoring, obesity, and comorbidities, as reported for middle aged populations. Asian race was associated with sleep‐disordered breathing.
Transient elastography for patients with chronic hepatitis B and C virus infection: Non‐invasive, quantitative assessment of liver fibrosis
Authors: Ogawa Eiichi , Furusyo Norihiro , Toyoda Kazuhiro , Takeoka Hiroaki , Otaguro Shigeru , Hamada Maki , Murata Masayuki , Sawayama Yasunori , Hayashi Jun 
Published: July 2007

Aim/Methods: The aim of the present study was to compare the diagnostic performance of transient elastography (FibroScan) with that of serum fibrosis markers and stages of hepatic fibrosis by biopsy in 68 patients with chronic hepatitis B virus (HBV) and in 161 patients with hepatitis C virus (HCV) infection.Results: The serum levels of hyaluronic acid (r = 0.601) and type IV collagen (r = 0.663) significantly positively associated with the FibroScan values (allP < 0.05). Classified by fibrosis stages, the median values of FibroScan were 3.5 kPa for F0, 6.4 kPa for F1, 9.5 kPa for F2, 11.4 kPa for F3, and 15.4 kPa forF4 in patients with chronic HBV infection, and were 6.3 kPa for F0, 6.7 kPa for F1, 9.1 kPa for F2, 13.7 kPa for F3, and 26.4 kPa for F4 in those with chronic HCV infection. The values were significantly correlated with fibrosis stage for both (HBV,r = 0.559,P = 0.0093, and HCV,r = 0.686,P < 0.0001).Conclusion: These results suggest that FibroScan is an efficient and simple method for evaluating liver fibrosis in patients with chronic infection, both for HBV and HCV.
SU‐DD‐A4‐03: A Validation Study of Concurrent Multimodality Segmentation
Authors: El Naqa I , Mutic S , Yang D , Khullar D , Deasy J 
Published: July 2007

Purpose: The acquisition of multiple images of varied yet complementary information is rapidly becoming the norm in radiotherapy treatment planning. Beside CT data sets, PET and/or MRI or MRS images are also being used to aid in the definition of the target volume (or normal structures) for treatment optimization. We have been developing new methods to integrate available imaging information (anatomical and/or physiological) for concurrent target registration and segmentation. Towards this goal, we have investigated several clustering and active contour methods for simultaneous 2D/3D segmentation/registration of multi‐modality images consisting of combinations of PET, CT, or MRI datasets. In this work, we present a phantom validation study of this approach. Method and Materials: A commercial anthropomorphic head phantom of average human size was used. Targets consisting of plastic spheres and rods were placed throughout the cranium section of the phantom. Tap water was used for CT imaging. For MRI and PET imaging, the water inside the phantom was doped with CuNO3 and 18F‐FDG, respectively. The cold spots spheres were considered as the segmentation targets (four spheres each is 25.4 mm in diameter). The rods were used as landmarks to assist in alignment. A geometric deformable model known as the multi‐valued level set (MVLS) method was applied as our computational vehicle. Results: The MVLS algorithm achieved 90% segmentation accuracy and less than 2% volume error when integrating all of the three modalities. This is contrasted with 74% segmentation accuracy and 4.4% volume error when using CT‐based systems only. Conclusion: We have validated a semi‐automatic method for integrating information from different imaging modalities. Our phantom study demonstrates the feasibility of the proposed image integration approach. This approach could potentially provide radiologists/oncologists with reliable and efficient tools to analyze simultaneously different modality data in different cancer sites.This work was supported by ACS‐IRG‐58‐010‐50 grant.
SU‐FF‐I‐58: A Software Toolkit for Multi‐Image Registration and Segmentation in IGRT and ART
Authors: Foskey M , Gash A , Han Q , Tracton G , Joshi S , Pizer S , Chaney E 
Published: July 2007

Purpose: Extracting information from images for image‐guided and adaptive radiation therapy usually involves segmentation and/or registration with a reference image. The purpose of this research was to develop and make freely available a software toolkit for research use that combines several registration and segmentation methods and is applicable to problems involving multiple sequential images. Method and Materials: Two automatic approaches have been integrated with standard interactive methods. One automatic approach solves PDEs describing visco‐elastic flow to register a set of target images with a reference image. Segmentations can then be transferred from the reference image to target images via corresponding deformation fields. The second method segments images via Bayesian posterior optimization of a 3D deformable shape model called an m‐rep. User efficiency has been improved by the ability to queue, view, work with, and compare multiple images and segmentations during a single session. The software was developed in C++ and runs on Windows and Linux. Results: The GUI, including a window with panes for standard orthogonal 2D views linked to a second 3D window, preserves a common look and feel for all three approaches. A set of treatment images of the same patient initially are rigidly registered to a reference image. The images are then segmented by the methods of choice. Unsatisfactory automatic results are edited with conventional methods. Registered images and segmentations are output in DICOM RT format. Conclusion: The toolkit combines multiple approaches for image registration and segmentation in a system specifically designed to support research on IGRT and ART. A cost‐free license to download and use the software is available at http://planunc.radonc.unc.edu.Research supported by NCI/NCRR R01 RR 01861501.
SU‐FF‐I‐76: Slot Scan Imaging Versus Anti‐Scatter Grid Method in Digital Chest Imaging‐ a 4‐AFC Study
Authors: Lai C , Shaw C , Liu X , Altunbas M , Chen L , Wang T , Han T 
Published: July 2007

Purpose: To investigate and compare the anti‐scatter grid and slot scanning methods for their effects on the observers' performance in digital chest imaging. Materials and Methods: Anthropomorphic chest phantom was imaged with an a‐Si/a‐Se flat‐panel based digital radiography system. The system was operated in both the slot scanning and full‐field modes. An anti‐scatter grid was used. Imaging technique was 120 kVp and 0.15 to 16 mAs for both modes. After that, the grid was removed and same imaging technique was applied to acquire phantom images for both modes. 1‐cm diameter computer‐simulated nodule with a nominal peak contrast ratio of 5% was used to generate simulated nodules at hilum and sub‐diaphragm locations by applying SPR values for all images. 4‐AFC experiment was conducted to measure the ratio of correct observations as a function of the exposure level for various imaging conditions and locations. 24 sets of four‐512×512 images were generated for each exposure level, resulting in generating 192 sets for each imaging condition and location. These images were displayed randomly on a review workstation. The ratios of correct observations versus exposure levels were computed for various imaging conditions and locations. Result: With low exposure, the observers' performance improved with the exposure level but reached the maximum at ∼4 mAs for all techniques. At the hilum location, slot scan imaging without grid performed the best, followed by full‐field imaging without grid. The use of an anti‐scatter grid in both full‐field and slot scan modes seemed to degrade the performance significantly. Conclusion: Improvement with the exposure level has been observed for all imaging techniques. However, the observers' performance reached the maximum at different rates depending on the nodule location and techniques.(This work was supported in part by a research grant EB000117 from the NIH‐NIBIB and a research grant CA104759 from the NIH‐NCI).
SU‐FF‐I‐82: Noise Cancellation and Onset Detection of Verbal Responses During Functional Magnetic Resonance Imaging
Authors: Sen A , Parrish T 
Published: July 2007

A method for scanner noise cancellation and detection of verbal responses during an fMRI experiment is presented. In recent fMRI experiments overt responses have been used to monitor the subject's response and the timing used in the statistical analysis.. Due to the presence of scanner noise, the subject's speech can be difficult to understand. Data were collected on a 3T scanner during EPI acquisition. A template of the scanner noise is created during the period of scanning that is used to allow the signal to reach equilibrium. For each TR intervals, correlation of the template is used to optimize the subtraction by a shift of +/− 5 pixels. A median filter (1×5) is used to remove spurious noise spikes resulting from an incomplete subtraction. Finally, a threshold is applied defined as 2 standard deviations above the baseline, to identify the verbal responses. The time position of each verbal response is obtained with respect to an initial setting.The result is an audio stream that is nearly free of scanner noise with a reduction in noise by 15 dB. The subject's voice is detectable. A spreadsheet of verbal response onsets is also created for use during analysis to improve the statistical model. Future implementation is aimed at having a real‐time version to monitor the subject during any form of imaging to provide additional levels of safety. The experimental data is sampled at a rate of 25000 samples/second. Figure 1, shows pictures of scanner signals, before and after the processing of an event related trial. Figure 2, shows the scanner signal before processing in one TR segment. Figure 3 shows the power spectrum plot of the audio signals, before and after processing. The result shows that it is possible to reduce the scanner noise by 15 db using this technique.
SU‐FF‐J‐58: Clinical Evaluation Using Digital Tomosynthesis for Positioning Verification of Breath‐Hold Liver Treatment
Authors: Fuller J , Wu Q , Godfrey D , Zhang J , Wang Z , Yoo S , Yin F 
Published: July 2007

Purpose: To demonstrate clinical feasibility of generating digital tomosynthesis (DTS) in a single breath‐hold (BH) period compared to multiple BH periods for CBCT acquisition and to examine on‐board BH‐DTS as an efficient alternative to BH‐CBCT for target localization of breath‐hold liver treatment. Methods & Materials: 3 patients receiving 3D conformal or IMRT treatments to the liver were retrospectively studied. Reference DTS images (RDTS) were generated using the BH planning CT and BH‐DTS images were reconstructed using the projection images acquired with BH‐CBCT. Matching between on‐board image set and reference image set was performed by (1) aligning bony anatomy near isocenter and (2) aligning target soft tissue using all image sets. Localization variations were calculated as the relative couch shifts in the vertical, longitudinal and lateral directions, as well as the relative couch rotations in pitch, yaw, and roll directions. Results: 10 – 40 degrees DTS images can be acquired within 1 single BH. Localization accuracy is in the range of 0.2 cm and 1.0 degree using the coronal‐view DTSs and is in the range of 0.35 cm and 1.6 degree using the for sagittal view DTS. The localization accuracy is comparable either using bony anatomy or using soft tissue. Conclusion: Rapid (< 10 sec.) BH‐DTS is more efficient than BH‐CBCT (> 5 min.) for daily 3D on‐board image guidance and localization of liver under breath‐hold radiation therapy.Partially supported by research grant from Varian Medical Systems.
SU‐FF‐T‐252: Improvement of Localization Accuracy by Using 3D Cone Beam CT for Stereotactic Body Radiation Therapy of Liver, Lung and Spine Lesions
Authors: Wang Z , Nelson J , Yoo S , Wu Q J , Kirkpatrick J , Larrier N , Meyer J , Willett C , Yin F 
Published: July 2007

Purpose: To compare treatment isocenter placement based on OBI 2D kV imaging and OBI 3D‐CBCT imaging for patients undergoing SBRT, and compare the CBCT based isocenter shifts among liver, lung and spine lesions. Material and Methods: 119 SBRT fractions were delivered to 40 lesions of 32 patients. The patients were initially localized with 2D orthogonal on‐board kV images. 3D on‐board CBCT images were then acquired to localize the isocenter for treatment. The shifts from 2D to 3D localization were recorded. Histograms, mean values and standard deviation of the isocenter shifts were calculated. Results: The isocenter shifts based on the 3D CBCT for all 119 SBRT fractions were 0.27 ± 0.25 cm, 0.19 ± 0.23 cm, and 0.23 ± 0.27 cm in the A‐P, C‐C, and M‐L direction, respectively. The mean values and standard deviations of the magnitudes of the shifts along AP, CC and ML directions were 0.30 ± 0.26 cm, 0.21 ± 0.20 cm, and 0.31 ± 0.35 cm for liver patients, 0.31 ± 0.29 cm, 0.30 ± 0.31 cm, and 0.28 ± 0.33 cm for lung patients, and 0.22 ± 0.21 cm, 0.13 ± 0.16 cm, and 0.18 ± 0.18 cm for spine patients. Conclusion: CBCT guidance enhances the setup accuracy of SBRT treatment by using 3D anatomical information.Partly supported by Varian Research Grant.
MO‐SAMS‐AUD‐01: Daily Localization — I: Kilovolt Imaging
Authors: Yin F , Yoo S , Moseley D , Sharpe M , Siewerdsen J 
Published: July 2007

As high‐precision 3‐D conformal radiation therapy and intensity‐modulated radiation therapy have become standard practice, radiographic imaging using kilovoltage (kV) x‐ray sources has been rapidly implemented for in‐room target localization and patient positioning to ensure conformal dose delivery. Various types of imaging devices are commercially available for clinical applications and their typical imaging functionalities include 2‐D radiographic and fluoroscopic imaging as well as 3‐D cone beam CT. There are substantial demands for fundamental understanding of what kind of systems can be used for clinical practice, when and what imaging systems should be used, how they can be properly used for daily target localization for different anatomical sites, and what kind of quality assurance programs are needed.In this session, we will briefly introduce the latest commercially available imaging systems using kV imaging for in‐room target localization and their imaging principles. Clinical applications and imaging protocols using these systems for accurate target localization and patient positioning will then be discussed. Finally, systematic quality assurance procedures will be presented.Objectives:1. Understand the latest commercially available technologies for in‐room kV radiography, fluoroscopy, and cone‐beam CT and their basic imaging principles.2. Understand the basic clinical imaging applications for daily localization.3. Understand the basic system limitations and QA components of a comprehensive QA program.
MO‐B‐BRA‐01: Practical Examples, Including IMRT, TBI, SRS
Authors: Rodgers J 
Published: July 2007

NCRP Report No. 151(December 2005), titled “Structural Shielding Design and Evaluation for Megavoltage X‐ and Gamma‐Ray Radiotherapy Facilities”, presents updated methods and data for radiation therapy room shielding design. These calculation methods are applied in examples representing the more common shielding design situations. A radiation therapy vault with a maze barrier and intended for use with IMRT and TBI procedures is the principal example. Detailed calculations of the barriers and door shielding structures are presented. Procedures for evaluating compliance with the NRC licensing constraint on dose equivalent in‐any‐one‐hour are presented. An example of a high‐energy room where photoneutron production is of concern is presented with focus on assessing the dose equivalent at the entrance and the maze door design.Objectives: Learn by worked examples (1) how to apply the methods and data presented in NCRP 151 for designing high energy therapy vault barriers; (2) how to determine prospectively if the barrier design is adequate to satisfy the public areas “2 mrem in‐any‐one‐hour” constraint when it is applicable.
MO‐D‐L100J‐09: A Multi‐Resolution, Multi‐Scale, Mutual Information Technique for Registration of High‐ and Low‐KVp Projections in Dual‐Energy Imaging
Authors: Dhanantwari A , Siewerdsen J , Shkumat N , Williams D , Moseley D , Paul N , Yorkston J , Van Metter R 
Published: July 2007

Purpose: In dual‐energy (DE) imaging, double‐shot acquisition provides superior DQE and detectability index compared to sandwiched detectors, but introduces the potential for misregistration artifacts (e.g., respiratory, cardiac, and bulk motion). This paper reports a projection registration scheme operating at various levels of scale and resolution to resolve misregistration errors prior to DE decomposition. Method and Materials: The method is based on joint histograms of the high‐ and low‐kVp images (or ROIs therein), with optimal image transformations computed to maximize the mutual information between the images. The image is subdivided into a series of ROIs, with an optimal transformation computed for each ROI. Large ROIs are downsampled to reduce the computational complexity of the optimization. The ROI transformations are smoothed and interpolated to determine a pixel‐wise transformation for the entire image. This is repeated with progressively smaller ROIs. Results: The results demonstrate that large scale ROIs (400×400 pixel) are effective in correcting bulk patient motion such as drift or relaxation. A second pass with a smaller ROI (200×200 pixel) corrects breathing and cardiac motion. A final pass with yet smaller ROIs (100×100 pixels) is effective at correcting the motion of fine bronchio‐vascular structure. The combination of these in an iterative multi‐resolution, multi‐scale method effectively registers the high‐ and low‐kVp projections such that DE images exhibit significantly reduced motion artifacts — particularly in the scapulae, aorta, heart, liver, and bronchioles. Expert radiologist readings suggest a significant improvement in image quality and diagnostic performance. Conclusion: The iterative, multi‐resolution, multi‐scale registration corrects misregistration progressively at scales ranging from bulk anatomical drift down to smaller scale motion such as that of fine pulmonary vasculature. The approach is a vital part of the DE image processing chain that has been implemented for a clinical DE imaging trial with 200 patients.Research partly supported by Eastman Kodak Co.
MO‐D‐M100J‐05: Robust Optimization to Accommodate Effects of Systematic Treatment Uncertainties
Authors: Lee E , Cha K , Bortfeld T , Deasy J 
Published: July 2007

Uncertainties in the precise locations of tumor voxels are inherent for a variety of reasons. It is therefore desirable to take those uncertainties into account, and further, to derive treatment planning methodologies that directly utilize information (e.g. probability distributions or actual trajectories) about the location of the target, including spatial uncertainties, so that resulting treatment plans exhibit normal tissue dose reduction, and potentially higher tumor doses.Two novel robust approaches are investigated. 1)Under‐dose probability(UDP) estimates the probability of the tumor receiving a dose less than a user‐defined critical dose. It can be modeled using linear mixed‐integer programming techniques. 2)Probability dose generation(PDG) designs treatment plans in which the probability of a voxel located in a target is factored during the dose generation process. Utilizing 4D‐CT scans of lung/liver cancer patients during different breathing phases(phases 0–9, 0:full‐inhale, 5:full‐exhale), four treatment planning strategies are compared. 1)Standard planning with a static PTV based on a single selected phase (control). 2)The Internal Target Volume (ITV) approach, where ITV is defined as the union of CTVs in all breathing phases. 3)Plans obtained with UDP. 4)Plans obtained via PDG. Sophisticated computational optimization techniques are used to solve each of these models.Compared to Standard and ITV plans, UDP and PDG plans offer good coverage, comparable min‐PTV‐dose, improved PTV‐conformity, and higher PTV‐dose. In addition, in lung, PDG reduces normal‐lung‐mean‐dose by 13% and heart‐mean‐dose by 20%; and UDP reduces esophagus‐mean‐dose by 70% and heart‐mean‐dose by 49%. In liver, PDG reduces normal‐liver‐ mean‐dose by 8% and other‐normal‐tissue‐mean‐dose by 26%, whereas UDP reduces normal‐liver‐mean‐dose by 10%, both with improved PTV‐conformity of 7%.Thus, the UDP and PDG approaches can result in treatment plans of increased robustness, they allow a reduction in mean dose to organs‐at‐risk and normal tissue, and in some cases, deliver higher dose to the tumor volume.