Abstract:
PURPOSE:Manual delineation of head and neck (H&N) organ-at-risk (OAR) structures for radiation therapy planning is time consuming and highly variable. Therefore, we developed a dynamic multiatlas selection-based approach for fast and reproducible segmentation. METHODS:Our approach dynamically selects and weights the appropriate number of atlases for weighted label fusion and generates segmentations and consensus maps indicating voxel-wise agreement between different atlases. Atlases were selected for a target as those exceeding an alignment weight called dynamic atlas attention index. Alignment weights were computed at the image level and called global weighted voting (GWV) or at the structure level and called structure weighted voting (SWV) by using a normalized metric computed as the sum of squared distances of computed tomography (CT)-radiodensity and modality-independent neighborhood descriptors (extracting edge information). Performance comparisons were performed using 77 H&N CT images from an internal Memorial Sloan-Kettering Cancer Center dataset (N = 45) and an external dataset (N = 32) using Dice similarity coefficient (DSC), Hausdorff distance (HD), 95th percentile of HD, median of maximum surface distance, and volume ratio error against expert delineation. Pairwise DSC accuracy comparisons of proposed (GWV, SWV) vs single best atlas (BA) or majority voting (MV) methods were performed using Wilcoxon rank-sum tests. RESULTS:Both SWV and GWV methods produced significantly better segmentation accuracy than BA (P < 0.001) and MV (P < 0.001) for all OARs within both datasets. SWV generated the most accurate segmentations with DSC of: 0.88 for oral cavity, 0.85 for mandible, 0.84 for cord, 0.76 for brainstem and parotids, 0.71 for larynx, and 0.60 for submandibular glands. SWV's accuracy exceeded GWV's for submandibular glands (DSC = 0.60 vs 0.52, P = 0.019). CONCLUSIONS:The contributed SWV and GWV methods generated more accurate automated segmentations than the other two multiatlas-based segmentation techniques. The consensus maps could be combined with segmentations to visualize voxel-wise consensus between atlases within OARs during manual review.
journal_name
Med Physjournal_title
Medical physicsauthors
Haq R,Berry SL,Deasy JO,Hunt M,Veeraraghavan Hdoi
10.1002/mp.13854subject
Has Abstractpub_date
2019-12-01 00:00:00pages
5612-5622issue
12eissn
0094-2405issn
2473-4209journal_volume
46pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:To evaluate two deformable image registration (DIR) algorithms for the purpose of contour mapping to support image guided adaptive radiotherapy (IGART) with 4D cone beam CT (4DCBCT). METHODS:Eleven locally advanced non-small cell lung cancer (NSCLC) patients underwent one planning 4D fan- beam CT (4DFBCT) and ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735821
更新日期:2012-06-01 00:00:00
abstract::An analytic expression is derived for the transmission of isotropic scattered radiation incident upon an ideal parallel grid. It is found that the expression for the transmission usually found in the literature overestimates the transmission by approximately a factor of two. ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594877
更新日期:1981-11-01 00:00:00
abstract:PURPOSE:In this study the Octavius detector 729 ionization chamber (IC) array with the Octavius 4D phantom was characterized for flattening filter (FF) and flattening filter free (FFF) static and rotational beams. The device was assessed for verification with FF and FFF RapidArc treatment plans. METHODS:The response o...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4817482
更新日期:2013-09-01 00:00:00
abstract:PURPOSE:Automatic breast ultrasound (ABUS) imaging has become an essential tool in breast cancer diagnosis since it provides complementary information to other imaging modalities. Lesion segmentation on ABUS is a prerequisite step of breast cancer computer-aided diagnosis (CAD). This work aims to develop a deep learnin...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14569
更新日期:2020-10-30 00:00:00
abstract:PURPOSE:We studied the sensitivity of a novel transmission fiber scintillator array designed and built for in line treatment verification. The purpose of this project is to assess the capability of the fiber detector array technology to detect treatment errors in real time without false positives to enhance patient saf...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735217
更新日期:2012-06-01 00:00:00
abstract::For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2168067
更新日期:2006-03-01 00:00:00
abstract:PURPOSE:The standardized uptake value (SUV) is a quantitative measure of FDG tumor uptake frequently used as a tool to monitor therapeutic response. This study aims to (i) assess the reproducibility and uncertainty of SUV max and SUV mean, due to purely statistical, i.e., nonbiological, effects and (ii) to establish th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3578604
更新日期:2011-05-01 00:00:00
abstract:PURPOSE:To evaluate the energy dependence of Gafchromic EBT3 film for establishing a quality assurance method of bolus electron conformal radiotherapy. METHODS:We irradiated electron beam to EBT3 films, which were set in the water tank. The linear accelerator used was Varian Clinac 21EX. The energy of electron beams w...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735200
更新日期:2012-06-01 00:00:00
abstract::The data from Meisberger et al. [Radiology 90, 953-957 (1968)] are often used as a basis for dose calculations in brachytherapy. In order to describe the absorbed dose in water around a brachytherapy point source, Meisberger provided a polynomial fit for different isotopes taking into account the effect of attenuation...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597583
更新日期:1995-05-01 00:00:00
abstract::A new energy selective detector for dual energy computed radiography has been developed that combines many of the advantages of x-ray tube voltage switching and single exposure double screen detectors. The new active detector utilizes electro-optical modulation of the response of the storage phosphor screens to allow ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597831
更新日期:1996-10-01 00:00:00
abstract:BACKGROUND:Deep learning methods for radiomics/computer-aided diagnosis (CADx) are often prohibited by small datasets, long computation time, and the need for extensive image preprocessing. AIMS:We aim to develop a breast CADx methodology that addresses the aforementioned issues by exploiting the efficiency of pre-tra...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12453
更新日期:2017-10-01 00:00:00
abstract::Monte Carlo dose calculations will potentially reduce systematic errors that may be present in currently used dose calculation algorithms. However, Monte Carlo calculations inherently contain random errors, or statistical uncertainty, the level of which decreases inversely with the square root of computation time. Our...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598916
更新日期:2000-03-01 00:00:00
abstract::The proper evaluation of the accuracy of a new computer program for radiation-therapy dosimetry requires consideration of both the mathematical algorithm used in the program and the performance required in clinical applications. As an example, our evaluation of the irregular-fields dosimetry program currently marketed...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594344
更新日期:1977-11-01 00:00:00
abstract:PURPOSE:The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4892174
更新日期:2014-09-01 00:00:00
abstract::Due to practical limitations such as inter- and intraleaf transmission, nondivergent leaf end design, and leaf scatter, multileaf collimators (MLCs) are unable to accurately produce the ideal fluence patterns generated by inverse planning systems. Consequently, low dose regions receive substantially more radiation tha...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2779862
更新日期:2007-10-01 00:00:00
abstract::We report on some extensions and further developments of a well-known microcalcification detection algorithm based on adaptive noise equalization. Tissue equivalent phantom images with and without labeled microcalcifications were subjected to this algorithm, and analyses of results revealed some shortcomings in the ap...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1359245
更新日期:2001-04-01 00:00:00
abstract::The purpose of this work is to calculate the dose perturbations due to the presence of iodine contrast media in catheter-based intravascular brachytherapy (IVBT). The EGSnrc Monte Carlo system was used to perform the calculation for the two most commonly used beta and gamma sources (90Sr and 192Ir as well as for a var...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1367279
更新日期:2001-05-01 00:00:00
abstract::The concept of the radiological depth is central to all algorithms which calculate radiation dose in a heterogeneous medium. For a discrete heterogeneous medium, consisting of regions of inhomogeneity, the radiological depth is usually presented as the sum over segments of the product of the segment length and the inh...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595739
更新日期:1985-01-01 00:00:00
abstract:PURPOSE:The aim of this work is to search for new metrics that could give more reliable acceptance/rejection criteria on the IMRT verification process and to offer solutions to the discrepancies found among different conventional metrics. Therefore, besides conventional metrics, new ones are proposed and evaluated with...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4964796
更新日期:2016-11-01 00:00:00
abstract:PURPOSE:The authors describe the integration of optical imaging with a targeted small animal irradiator device, focusing on design, instrumentation, 2D to 3D image registration, 2D targeting, and the accuracy of recovering and mapping the optical signal to a 3D surface generated from the cone-beam computed tomography (...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4894730
更新日期:2014-10-01 00:00:00
abstract::This article is the first in a series on the calculation of electron dose using multiple-scattering theory. In it we develop a unified theory, which we term Gaussian multiple-scattering theory, starting from a number of contributions already in the literature: the Fermi-Eyges multiple-scattering theory, the Yang path ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596166
更新日期:1988-03-01 00:00:00
abstract:PURPOSE:To track variations in the deformation of the arterial wall noninvasively by estimating the accumulated displacement and strain over a cardiac cycle may provide useful indicators of vascular health. METHODS:In this paper, we propose an approach to track a region of interest (ROI) locally and estimate arterial ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4722746
更新日期:2012-07-01 00:00:00
abstract:PURPOSE:Dynamic myocardial perfusion computed tomography (DM-PCT) imaging offers benefits over quantitative assessment of myocardial blood flow (MBF) for diagnosis and risk stratification of coronary artery disease. However, one major drawback of DM-PCT imaging is that a high radiation level is imparted by repeated sca...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12285
更新日期:2017-09-01 00:00:00
abstract::When parallel-plate chambers are used for dosimetry in electron fields, the AAPM dosimetry protocol recommends a value of 1.0 for the replacement correction factor, P(repl),pp,E, until further data become available. Here, P(repl),pp,E for five commercially available parallel-plate chambers was measured as a function o...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596740
更新日期:1991-11-01 00:00:00
abstract::The increasing complexity of modern radiation therapy planning and delivery challenges traditional prescriptive quality management (QM) methods, such as many of those included in guidelines published by organizations such as the AAPM, ASTRO, ACR, ESTRO, and IAEA. These prescriptive guidelines have traditionally focuse...
journal_title:Medical physics
pub_type: 共识发展会议,杂志文章,实务指引
doi:10.1118/1.4947547
更新日期:2016-07-01 00:00:00
abstract::Patient-specific intensity-modulated radiotherapy (IMRT) verifications require an accurate two-dimensional dosimeter that is not labor-intensive. We assessed the precision and reproducibility of film calibrations over time, measured the elemental composition of the film, measured the intermittency effect, and measured...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1852791
更新日期:2005-02-01 00:00:00
abstract:PURPOSE:Variations during breast tissue development can influence later breast cancer risk. In particular, prolonged nulliparity increases risk. The authors used optical spectroscopy to compare breast tissue in 115 nulliparous women aged 31-40 (group 2) to 140 nulliparous women aged 18-21 (group 1), and also to 36 paro...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3276737
更新日期:2010-02-01 00:00:00
abstract:PURPOSE:The authors investigated the potential of optimized noncoplanar irradiation trajectories for volumetric modulated arc therapy (VMAT) treatments of nasopharyngeal patients and studied the trade-off between treatment plan quality and delivery time in radiation therapy. METHODS:For three nasopharyngeal patients, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4914863
更新日期:2015-05-01 00:00:00
abstract::We are developing computerized methods for characterizing the bone texture pattern from digitized skeletal radiographs. For this method to be useful clinically, it must be able to distinguish between weak and strong bone under the range of exposure conditions potentially encountered in the clinical setting. In this st...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598858
更新日期:2000-01-01 00:00:00
abstract::The calibration (in rad/nC) of an air-filled tissue-equivalent ionization chamber for neutrons of 15-MeV average energy was determined by measuring absolute fluences and calculating the kerma per unit fluence. The neutron calibration determined from the gamma-ray calibration and application of the Bragg-Gray relation ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594310
更新日期:1977-03-01 00:00:00