Abstract:
PURPOSE:Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to provide the missing spatial information. 3D US image acquisition is mainly based on mechanical, electromagnetic, and freehand tracking of conventional 2D US transducers, or 2D array transducers available on high-end machines. These approaches share many problems during clinical use for interventional liver imaging due to lack of flexibility and compatibility with interventional equipment, limited field-of-view (FOV), and significant capital cost compared to the benefits they introduce. In this paper, a novel system for mechanical 3D US scanning is introduced to address these issues. METHODS:The authors have developed a handheld mechanical 3D US system that incorporates mechanical translation and tilt sector sweeping of any standard 2D US transducer to acquire 3D images. Each mechanical scanning function can be operated independently or may be combined to allow for a hybrid wide FOV acquisition. The hybrid motion mode facilitates registration of other modalities (e.g., CT or MRI) to the intraoperative 3D US images by providing a larger FOV in which to acquire anatomical information. The tilting mechanism of the developed mover allows image acquisition in the intercostal rib space to avoid acoustic shadowing from bone. The geometric and volumetric scanning validity of the 3D US system was evaluated on tissue mimicking US phantoms for different modes of operation. Identical experiments were performed on a commercially available 3D US system for direct comparison. To replicate a clinical scenario, the authors evaluated their 3D US system by comparing it to CT for measurement of angle and distance between interventional needles in different configurations, similar to those used for percutaneous ablation of liver tumors. RESULTS:The mean geometrical hybrid 3D reconstruction error measured from scanning of a known string phantom was less than 1 mm in two directions and 2.5 mm in the scanning direction, which was comparable or better than the same measurements obtained from a commercially available 3D US system. The error in volume measurements of spherical phantom models depended on depth of the object. For a 20 cm(3) model at a depth of 15 cm, a standard depth for liver imaging, the mean error was 3.6% ± 4.5% comparable to the 2.3% ± 1.8% error for the 3D US commercial system. The error in 3D US measurement of the tip distance and angle between two microwave ablation antennas inserted into the phantom was 0.9 ± 0.5 mm and 1.1° ± 0.7°, respectively. CONCLUSIONS:A 3D US system with hybrid scanning motions for large field-of-view 3D abdominal imaging has been developed and validated. The superior spatial information provided by 3D US might enhance image-guidance for percutaneous interventional treatment of liver malignancies. The system has potential to be integrated with other liver procedures and has application in other abdominal organs such as kidneys, spleen, or adrenals.
journal_name
Med Physjournal_title
Medical physicsauthors
Neshat H,Cool DW,Barker K,Gardi L,Kakani N,Fenster Adoi
10.1118/1.4824326subject
Has Abstractpub_date
2013-11-01 00:00:00pages
112903issue
11eissn
0094-2405issn
2473-4209journal_volume
40pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::To achieve increased image acquisition speed or better image quality, several read-out methods for a matrix ionization chamber system have been investigated. In this device, which is applied for portal imaging in radiation therapy, 256 x 256 small liquid-filled ionization chambers are scanned by switching the polarizi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596829
更新日期:1992-03-01 00:00:00
abstract:PURPOSE:The purpose of this study is to evaluate the feasibility of kilovoltage cone-beam CT (CBCT) images that are obtained with the Varian On-Board Imager in dose calculation at each radiation therapy. METHODS:CBCT images are commonly degraded by scattered radiations originating in the patient's body, and so the CT ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734936
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Quantitative cone-beam CT (CBCT) imaging is on increasing demand for high-performance image guided radiation therapy (IGRT). However, the current CBCT has poor image qualities mainly due to scatter contamination. Its current clinical application is therefore limited to patient setup based on only bony structure...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3693050
更新日期:2012-04-01 00:00:00
abstract::An important point to consider in a brachytherapy dosimetry study is the phantom size involved in calculations or experimental measurements. As pointed out by Williamson [Med. Phys. 18, 776-786 (1991)] this topic has a relevant influence on final dosimetric results. Presently, one-dimensional (1-D) algorithms and newl...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1759826
更新日期:2004-07-01 00:00:00
abstract:PURPOSE:The use of 4D computed tomography (4D-CT) of the lung is important in lung cancer radiotherapy for tumor localization and treatment planning. Sometimes, dense sampling is not acquired along the superior-inferior direction. This disadvantage results in an interslice thickness that is much greater than in-plane v...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4899185
更新日期:2014-11-01 00:00:00
abstract:PURPOSE:To obtain on-treatment volumetric patient anatomy during respiratory gated volumetric modulated arc therapy (VMAT). METHODS:On-board imaging device integrated with Linacs offers a viable tool for obtaining patient anatomy during radiation treatment delivery. In this study, the authors acquired beam-level kV im...
journal_title:Medical physics
pub_type: 信件
doi:10.1118/1.4794925
更新日期:2013-04-01 00:00:00
abstract::Hyperthermia, as an adjuvant with radiation and chemotherapy, has shown promise in the treatment of cancer. The relevant biological effects of a hyperthermia treatment are both time and temperature-dependent, creating a need for accurate thermometry. We present a novel noninvasive thermometry modality that combines a ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1782677
更新日期:2004-10-01 00:00:00
abstract:PURPOSE:Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckl...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4922206
更新日期:2015-07-01 00:00:00
abstract:PURPOSE:Diffusion magnetic resonance imaging (MRI) in combination with functional MRI promises a whole new vista for scientists to investigate noninvasively the structural and functional connectivity of the human brain-the human connectome, which had heretofore been out of reach. As with other imaging modalities, diffu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3700166
更新日期:2012-05-01 00:00:00
abstract::A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-microm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1523932
更新日期:2002-12-01 00:00:00
abstract::Rotational angiography (RA) gantries are used routinely to acquire sequences of projection images of patients from which 3D renderings of vascular structures are generated using Feldkamp cone-beam reconstruction algorithms. However, these systems have limited resolution (<4 lp/mm). Micro-computed tomography (micro-CT)...
journal_title:Medical physics
pub_type: 信件
doi:10.1118/1.2989989
更新日期:2008-10-01 00:00:00
abstract:PURPOSE:To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. METHODS:Data from 50 patients with lung lesions who underwent a CT fluoroscop...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4884231
更新日期:2014-07-01 00:00:00
abstract:PURPOSE:Transcranial magnetic resonance-guided focused ultrasound surgery is a noninvasive technique for causing selective tissue necrosis. Variations in density, thickness, and shape of the skull cause aberrations in the location and shape of the focal zone. In this paper, the authors propose a hybrid simulation-MR-AR...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4865778
更新日期:2014-03-01 00:00:00
abstract::Approximately 70-85% of breast biopsies are performed on benign lesions. To reduce this high number of biopsies performed on benign lesions, a case-based reasoning (CBR) classifier was developed to predict biopsy results from BI-RADS findings. We used 1433 (931 benign) biopsy-proven mammographic cases. CBR similarity ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1501140
更新日期:2002-09-01 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::The analysis and understanding of results of computed tomography (CT) require an understanding of photon attenuation in matter. The high sensitivity and resolution of these devices coupled with the use of a polychromatic photon source require a level and breadth of understanding about photon attenuation not usually re...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594199
更新日期:1975-11-01 00:00:00
abstract::Skin entrance doses of patients undergoing interventional x-ray procedures are capable of causing skin damage and should be monitored routinely. Single TLD chips are not suitable because the location of maximum skin exposure cannot be predicted. Most photographic films are too sensitive at diagnostic x-ray energies fo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597973
更新日期:1997-10-01 00:00:00
abstract::Fluoroscopy is a low dose imaging technique. As such, a very sensitive detector is required to create images of good quality. Present day flat panel active matrix read out systems introduce an amount of noise that inhibits present direct and indirect methods from producing optimal quality images at fluoroscopic exposu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1513157
更新日期:2002-11-01 00:00:00
abstract::Heating rate (HR) patterns in cylindrical structures were studied with inhomogeneous limb phantoms. These phantoms, arm and thigh models consisting of fat, bone, and muscle material, were heated with Clini-Therm L, M, and MS applicators at 915 MHz. The thigh model is 18 cm in diameter with 2.65-cm-thick fat on the out...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596627
更新日期:1991-11-01 00:00:00
abstract:PURPOSE:To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch tra...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13887
更新日期:2020-02-01 00:00:00
abstract:PURPOSE:Examine the use of TomoDose for Tomotherapy quality assurance. METHODS:Baseline TomoDose profiles are acquired annually in accordance with TG-148. During monthly quality assurance, TomoDose is irradiated with a static beam and referenced to baseline. Differences between superimposed profiles are evaluated mont...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735202
更新日期:2012-06-01 00:00:00
abstract::The scattered-photon part of pencil-beam dose kernels for high-energy x-ray beams can be derived experimentally by differentiating the broad-beam scatter-to-primary dose ratio as a function of radius. Formally, this requires a uniform and parallel beam, and the procedure is complicated by the nonideal, actual beam con...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597884
更新日期:1996-09-01 00:00:00
abstract:PURPOSE:To use machine-learning algorithms and blur measure (BM) operators to automatically detect motion blur in mammograms. Motion blur has been reported to reduce lesion detection performance and mask small abnormalities, resulting in failure to detect them until they reach more advanced stages. Automatic detection ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14069
更新日期:2020-04-01 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::Monte Carlo (MC) techniques can be used to build a simulation model of an electron accelerator to calculate output factors for electron fields. This can be useful during commissioning of electron beams from a linac and in clinical practice where irregular fields are also encountered. The Monte Carlo code BEAM/EGS4 was...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1373402
更新日期:2001-06-01 00:00:00
abstract:PURPOSE:A preobject grid can reduce and correct scatter in cone beam computed tomography (CBCT). However, half of the signal in each projection is blocked by the grid. A synchronized moving grid (SMOG) has been proposed to acquire two complimentary projections at each gantry position and merge them into one complete pr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4937934
更新日期:2016-01-01 00:00:00
abstract::The most favorable treatment for moving body anatomy should aim at utilizing organ motion to minimize the dose to sensitive structures without compromising the dose delivered to the target. The solution of the problem of appropriate intensity redistribution over different phases of body motion is achievable in dynamic...
journal_title:Medical physics
pub_type: 信件
doi:10.1118/1.2804722
更新日期:2007-12-01 00:00:00
abstract::Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597867
更新日期:1996-07-01 00:00:00
abstract:PURPOSE:Optically stimulated luminescence (OSL) dosimetry has been recently introduced in radiation therapy as a potential alternative to the thermoluminescent dosimeter (TLD) system. The aim of this study was to investigate the feasibility of using OSL point dosimeters in the energy range used in diagnostic imaging. ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3602456
更新日期:2011-07-01 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