Abstract：
:The assessment of differential left and right lung function is important for patients under consideration for lung resection procedures such as single lung transplantation. We developed an automated, knowledge-based segmentation algorithm for purposes of deriving functional information from dynamic computed tomography (CT) image data. Median lung attenuation (HU) and area measurements were automatically calculated for each lung from thoracic CT images acquired during a forced expiratory maneuver as indicators of the amount and rate of airflow. The accuracy of these derived measures from fully automated segmentation was validated against those from segmentation using manual editing by an expert observer. A total of 1313 axial images were analyzed from 49 patients. The images were segmented using our knowledge-based system that identifies the chest wall, mediastinum, trachea, large airways and lung parenchyma on CT images. The key components of the system are an anatomical model, an inference engine and image processing routines, and segmentation involves matching objects extracted from the image to anatomical objects described in the model. The segmentation results from all images were inspected by the expert observer. Manual editing was required to correct 183 (13.94%) of the images, and the sensitivity, specificity, and accuracy of the knowledge-based segmentation were greater than 98.55% in classifying pixels as lung or nonlung. There was no significant difference between median lung attenuation or area values from automated and edited segmentations (p > 0.70). Using the knowledge-based segmentation method we can automatically derive indirect quantitative measures of single lung function that cannot be obtained using conventional pulmonary function tests.
journal_name
Med Physjournal_title
Medical physicsauthors
Brown MS,Goldin JG,McNitt-Gray MF,Greaser LE,Sapra A,Li KT,Sayre JW,Martin K,Aberle DRdoi
10.1118/1.598898subject
Has Abstractpub_date
2000-03-01 00:00:00pages
592-8issue
3eissn
0094-2405issn
2473-4209journal_volume
27pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：OBJECTIVE:Carbon ion particle therapy delivers sharp Bragg's peaks, and hence can produce dose delivery of very high precision and conformality. To complement this characteristic, particle therapy centers implement a number of technologies unique to these centers, and are not commonly known to the medical physics commu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735351
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:To investigate the feasibility of using the high Zeff storage phosphor material BaFBrI:Eu2+ in conjunction with the low Zeff storage phosphor material KCl:Eu2+ for simultaneous proton dose and linear energy transfer (LET) measurements by 1) measuring the fundamental optical and dosimetric properties of BaFBrI:E...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14748
更新日期：2021-02-01 00:00:00
abstract：:Linac calibration is done in water, but patients are comprised primarily of soft tissue. Conceptually, and specified in NRG/RTOG trials, dose should be reported as dose-to-muscle to describe the dose to the patient. Historically, the dose-to-water of the linac calibration was often converted to dose-to-muscle for pati...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13995
更新日期：2020-03-01 00:00:00
abstract：PURPOSE:Different low-signal correction (LSC) methods have been shown to efficiently reduce noise streaks and noise level in CT to provide acceptable images at low-radiation dose levels. These methods usually result in CT images with highly shift-variant and anisotropic spatial resolution and noise, which makes the par...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12855
更新日期：2018-05-01 00:00:00
abstract：:Quantitation of planar radionuclide images is hampered by structures containing radioactivity which overlie or underlie the organ of interest. The introduction of single photon emission computerized tomography (SPECT) overcame this problem to a large extent and enhanced the contrast of the images. Attenuation of photo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596684
更新日期：1991-05-01 00:00:00
abstract：PURPOSE:To investigate the dosimetric robustness of dynamically collimated proton therapy (DCPT) treatment plans delivered using a dynamic collimation system (DCS) with respect to random uncertainties in beam spot and collimator position as well as systematic offsets in the DCS mounting alignment. This work also demons...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14208
更新日期：2020-08-01 00:00:00
abstract：PURPOSE:Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. METHODS:A graph cuts segmentation metho...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3682171
更新日期：2012-03-01 00:00:00
abstract：PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12374
更新日期：2017-09-01 00:00:00
abstract：:This paper investigates the effect of the waterproofing sleeve on the calibration of kilovoltage photon beams (50-300 kV). The sleeve effect correction factor, ps has been calculated using the Monte Carlo method as the ratios of the air kerma in an air cavity of a cylindrical chamber without the waterproofing sleeve t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598039
更新日期：1997-09-01 00:00:00
abstract：PURPOSE:Modulated electron radiation therapy (MERT) can offer significant advantages for breast treatments over conventional radiotherapy in terms of sparing distal critical structures. While intensity modulated radiation therapy (IMRT) has the advantage of achieving better dose homogeneity inside the target combining ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735665
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The automated segmentation of each lung and trachea in CT scans is commonly taken as a solved problem. Indeed, existing approaches may easily fail in the presence of some abnormalities caused by a disease, trauma, or previous surgery. For robustness, we present ALTIS (implementation is available at http://lids....
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13773
更新日期：2019-11-01 00:00:00
abstract：PURPOSE:To use EGSnrc Monte Carlo simulations for magnetic field dosimetry to determine optimal measurement orientations, calculate beam quality conversion factors for 32 cylindrical and three parallel-plate (PP) ion chambers, evaluate the beam quality and angular dependence of these factors, and examine the magnetic f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12716
更新日期：2018-02-01 00:00:00
abstract：PURPOSE:Small animal immobilization devices facilitate positioning of animals for reproducible imaging and accurate focal radiation therapy. In this study, the authors demonstrate the use of three-dimensional (3D) printing technology to fabricate a custom-designed mouse head restraint. The authors evaluate the accuracy...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4933200
更新日期：2015-11-01 00:00:00
abstract：PURPOSE:This study investigated the dosimetry performance of a linear fiber-optic coupled dosimeter with a sensitive element varying from 3 to 15 cm in length. The dosimeter is comprised of a tissue equivalent plastic scintillating fiber coupled to a photomultiplier tube (PMT). The sensitive element has a length repres...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734756
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The authors have recently developed a cine-mode T2*/T1-weighted 4D-MRI technique and a sequential-mode T2-weighted 4D-MRI technique for imaging respiratory motion. This study aims at investigating which 4D-MRI image acquisition mode, cine or sequential, provides more accurate measurement of organ motion during ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4938066
更新日期：2016-01-01 00:00:00
abstract：:Direct comparisons of the National Institute of Standards and Technology's (NIST) Ritz 20 kV to 100 kV standard free-air ionization chamber and a portable variable-length free-air ionization chamber designed by the University of Wisconsin-Madison Accredited Dosimetry Calibration Laboratory (UW-ADCL) were made on NISTs...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598148
更新日期：1997-08-01 00:00:00
abstract：:An adaptive linear element (Adaline) was developed to estimate the two-dimensional scatter exposure distribution in digital portable chest radiographs (DPCXR). DPCXRs and quantitative scatter exposure measurements at 64 locations throughout the chest were acquired for ten radiographically normal patients. The Adaline ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596978
更新日期：1993-07-01 00:00:00
abstract：:The GEANT4 application for tomographic emission (GATE) is one of the most detailed Monte Carlo simulation tools for SPECT and PET. It allows for realistic phantoms, complex decay schemes, and a large variety of detector geometries. However, only a fraction of the information in each particle history is available for p...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3078045
更新日期：2009-04-01 00:00:00
abstract：PURPOSE:Measured values of ultrasound attenuation in bone represent a combination of different loss mechanisms. As a wave is transmitted from a fluid into bone, reflections occur at the interface. In the bone, mode conversion occurs between longitudinal and shear modes and the mechanical wave is scattered by its comple...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3668316
更新日期：2012-01-01 00:00:00
abstract：PURPOSE:Having been overlooked for many years, research is now starting to take into account the directional distribution of neutron workplace fields. Existing neutron dosimetry instrumentation does not account for this directional distribution, resulting in conservative estimates of dose in neutron workplace fields (b...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4964456
更新日期：2016-11-01 00:00:00
abstract：:In patients with lymphoma, identification and quantification of the tumor extent on serial CT examinations is critical for assessing tumor response to therapy. In this paper, we present a computer method to automatically match and segment lymphomas in follow-up CT images. The method requires that target lymph nodes in...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2404617
更新日期：2007-01-01 00:00:00
abstract：PURPOSE:In fluoroscopy-guided clinical procedures that involve tracking objects over long treatment times, there is a need for reducing the amount of imaging dose delivered to the patient and the operating staff. In this study, we introduce a feedback metric to minimize tube current while maintaining a targeting precis...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734878
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:This paper describes the low-kV spectral optimization of dual-energy CT (DECT) equipped with high-kV tin filtration for the quantitative acquisition of electron density information, which is essential for treatment planning in radiotherapy. In addition, an analytical DECT image simulation was preliminarily perf...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3584200
更新日期：2011-06-01 00:00:00
abstract：:A four-parameter Laplace transform pair model, which accurately reconstructs an experimental bremsstrahlung spectrum from attenuation data, is presented. Computed spectral values with both aluminum and copper attenuators generally agree with experimental 70-kVp data to better than 2%. Reconstructed spectra at other kV...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595193
更新日期：1982-11-01 00:00:00
abstract：PURPOSE:The goals of stereotactic radiosurgery (SRS) are the ablation of target tissue and sparing of critical normal tissue. We develop tools to aid in the selection of collimation and prescription (Rx) isodose line to optimize the dose gradient for single isocenter intracranial stereotactic radiosurgery (SRS) with Ga...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735542
更新日期：2012-06-01 00:00:00
abstract：:A contrast-detail (CD) experiment was performed to study the effect of lossy compression on computed radiographic (CR) images. Digital CR images of a phantom were compressed by quantizing the full-frame discrete cosine transform and Huffman encoding the result. Since low-contrast detectability is directly linked to an...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597489
更新日期：1995-06-01 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：:A suitable was phantom was designed for evaluating various film techniques used in subtraction radiography. Holes are drilled in a slab of wax and filled with various concentrations of iodinated wax, producing disk-shaped regions with diffuse borders. The technical details of construction and a representative applicat...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594371
更新日期：1977-05-01 00:00:00
abstract：:Separation of water from fat tissues in magnetic resonance imaging is important for many applications because signals from fat tissues often interfere with diagnoses that are usually based on water signal characteristics. Water and fat can be separated with images acquired at different echo time shifts. The three-poin...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2952644
更新日期：2008-08-01 00:00:00
abstract：PURPOSE:We have recently developed a dynamic tumor tracking irradiation system using Vero4DRT (MHI-Tm2 000). It is needed to create a 4D correlation model between a fiducial marker implanted near a tumor and an external surrogate as a function of time by continuously acquiring both fluoroscopy images and external surro...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734978
更新日期：2012-06-01 00:00:00
