Abstract：
PURPOSE:We propose a new metric called Distance Discordance (DD), which is defined as the distance between two anatomic points from two moving images, which are co-located on some reference image, when deformed onto another reference image. METHODS:To demonstrate the concept of DD, we created a reference software phantom which contains two objects. The first object (1) consists of a hollow box with a fixed size core and variable wall thickness. The second object (2) consists of a solid box of fixed size and arbitrary location. 7 different variations of the fixed phantom were created. Each phantom was deformed onto every other phantom using two B-Spline DIR algorithms available in Elastix and Plastimatch. Voxels were sampled from the reference phantom [1], which were also deformed from moving phantoms [2…6], and we find the differences in their corresponding location on phantom [7]. Each voxel results in a distribution of DD values, which we call distance discordance histogram (DDH). We also demonstrate this concept in 8 Head & Neck patients. RESULTS:The two image registration algorithms produced two different DD results for the same phantom image set. The mean values of the DDH were slightly lower for Elastix (0-1.28 cm) as compared to the values produced by Plastimatch (0-1.43 cm). The combined DDH for the H&N patients followed a lognormal distribution with a mean of 0.45 cm and std. deviation of 0.42 cm. CONCLUSIONS:The proposed distance discordance (DD) metric is an easily interpretable, quantitative tool that can be used to evaluate the effect of inter-patient variability on the goodness of the registration in different parts of the patient anatomy. Therefore, it can be utilized to exclude certain images based on their DDH characteristics. In addition, this metric does not rely on 'ground truth' or the presence of contoured structures.
journal_name
Med Physjournal_title
Medical physicsauthors
Berns Edoi
10.1118/1.4736139subject
Has Abstractpub_date
2012-06-01 00:00:00pages
3954issue
6Part27eissn
0094-2405issn
2473-4209journal_volume
39pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:Breast magnetic resonance imaging is highly sensitive but not very specific for the detection of breast cancer. Opportunities exist to supplement the image acquisition with a more specific modality provided the technical challenges of meeting space limitations inside the bore, restricted breast access, and elec...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4820361
更新日期：2013-10-01 00:00:00
abstract：PURPOSE:Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite elemen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4942813
更新日期：2016-04-01 00:00:00
abstract：:Purpose To investigate narrow, elongated magnetically focused proton beams and compare their properties with passively collimated beams using Monte Carlo simulation. METHODS:We performed Geant4 Monte Carlo simulations involving a single quadrapole focusing magnet, thereby creating a flattened beam with an elongated e...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735386
更新日期：2012-06-01 00:00:00
abstract：:Calibration of an imported strontium-90 ophthalmic applicator at the U.S. National Bureau of Standards (now the National Institute of Standards and Technology) has disclose a significant discrepancy in dose rate calibration (32%-35%) with that quoted by the manufacturer. The University of Wisconsin has investigated th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596702
更新日期：1991-03-01 00:00:00
abstract：:The method of magnetic resonance imaging (MRI) was an extension of nuclear magnetic resonance (NMR) spectroscopy that was enabled by computational systems capable of performing the Fast Fourier Transform. Initially, a diverse group of methods were proposed for producing images with NMR, with the multi-slice spin-warp ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4736176
更新日期：2012-06-01 00:00:00
abstract：:Conventional IMRT dose verification using film and ion chamber measurements is useful but limited with respect to the actual dose distribution received by the patient. The Monte Carlo simulation has been introduced as an independent dose verification tool for IMRT using the patient CT data and MLC leaf sequence files,...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2208916
更新日期：2006-07-01 00:00:00
abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1773631
更新日期：2004-08-01 00:00:00
abstract：PURPOSE:To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. METHODS:A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was use...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4932364
更新日期：2015-11-01 00:00:00
abstract：PURPOSE:For almost four decades bead and wire ramps have been used in the evaluation of slice width as part of QA testing for CT scanners. While each of these approaches have been recognized and accepted as reliable, in this paper we investigate the differences, advantages and limitations of these tools. Moreover, we s...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734753
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The authors' objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-sp...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892606
更新日期：2014-09-01 00:00:00
abstract：:The effectiveness of film-screen mammography is limited by tradeoffs between latitude and contrast, film granularity, and the need to increase dose when antiscatter methods are used. We are currently developing a scanned-projection digital mammography (SPDM) system to overcome these limitations. The system consists of...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596147
更新日期：1987-09-01 00:00:00
abstract：:Pixel size is of great interest in the flat-panel detector design because of its potential impact on image quality. In the particular case of angiographic x-ray fluoroscopy, small pixels are required in order to adequately visualize interventional devices such as guidewires and stents which have wire diameters as smal...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2169907
更新日期：2006-03-01 00:00:00
abstract：PURPOSE:Atherosclerosis of peripheral cerebral arteries can lead to stroke either by stenosis formation or plaque rupture. This pathology is initiated by the alteration of arterial wall mechanical properties shown to be assessable by ultrasound elastography. Recently, noninvasive vascular elastography (NIVE) was introd...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3539701
更新日期：2011-02-01 00:00:00
abstract：PURPOSE:Pulse pileup occurring at high x-ray fluxes can severely degrade the energy resolution provided by a photon counting detector, which can represent a problem in spectroscopic CT when performing quantitative material discrimination tasks. As the effects of pileup can be most easily seen as a degradation of a dete...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4820535
更新日期：2013-10-01 00:00:00
abstract：:This paper describes a multileaf collimator, designed to obtain irregularly shaped neutron fields, that fits into an existing fixed field-size collimator system. The shape of the desired portal field is obtained by appropriately setting the position of each leaf of the collimator. The collimator consists of 40 polyeth...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596084
更新日期：1987-03-01 00:00:00
abstract：PURPOSE:Modern clinical accelerators are capable of producing ion beams from protons up to neon. This work compares the depth dose distribution and corresponding dose averaged linear energy transfer (LET) distribution, which is related to the biological effectiveness, for different ion beams (¹H, ⁴He, ⁶Li, ⁸Be, ¹⁰B, ¹²...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3662911
更新日期：2011-12-01 00:00:00
abstract：:A method for optimizing MR imaging pulse sequence parameters in a statistical framework is presented. Parameters are defined to be optimal when the resulting scalar images yield optimal image segmentations using Bayesian pixel classification. Thus, Bayes risk is used as the objective function to minimize. Approximatio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597425
更新日期：1995-10-01 00:00:00
abstract：:In this paper, a unified framework of iterative algebraic reconstruction for emission computed tomography (ECT) and its application to positron emission tomography (PET) is presented. The unified framework is based on an algebraic image restoration model and contains conventional iterative algebraic reconstruction alg...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596954
更新日期：1993-11-01 00:00:00
abstract：PURPOSE:When an intensity-modulated radiation beam is delivered to a moving target, the interplay effect between dynamic beam delivery and the target motion due to miss-synchronization can cause unpredictable dose delivery. The portal dose image in electronic portal imaging device (EPID) represents radiation attenuated...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4799941
更新日期：2013-05-01 00:00:00
abstract：:Fourier transform infrared (FTIR) microspectroscopic imaging and small angle x-ray scattering (SAXS) were combined to investigate the supramolecular structure of collagen from 27 tissue sections from patients undergoing mastectomy, excisional biopsy, or mammoplasty. Both techniques were correlated by matching the scat...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2890391
更新日期：2008-05-01 00:00:00
abstract：:When treating prostate cancer using high dose rate (HDR) brachytherapy, overdosing the rectal wall may lead to post-treatment rectal complications. An area of concern is related to how the rectal wall dose is calculated by treatment planning systems (TPSs). TPSs are used to calculate the dose delivered to the rectal w...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3031111
更新日期：2009-01-01 00:00:00
abstract：PURPOSE:Four-dimensional volumetric modulated arc therapy (4D VMAT) and four-dimensional intensity-modulated radiotherapy (4D IMRT) are developing radiation therapy treatment strategies designed to maximize dose conformality, minimize normal tissue dose, and deliver the treatment as efficiently as possible. The patient...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12778
更新日期：2018-04-01 00:00:00
abstract：PURPOSE:Bone strength is the key factor impacting fracture risk. Assessment of bone strength from high-resolution (HR) images have largely relied on linear micro-finite element analysis (μFEA) even though failure always occurs beyond the yield point, which is outside the linear regime. Nonlinear μFEA may therefore be m...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4802085
更新日期：2013-05-01 00:00:00
abstract：PURPOSE:To develop and validate a multivariate statistical method to optimize scanning parameters for material quantification in spectral x-rayimaging. METHODS:An optimization metric was constructed by extensively sampling the thickness space for the expected number of counts for m (two or three) materials. This resul...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734708
更新日期：2012-06-01 00:00:00
abstract：:Digital tomosynthesis is an imaging technique to produce a tomographic image from a series of angular digital images in a manner similar to conventional focal plane tomography. Unlike film focal plane tomography, the acquisition of the data in a C-arm geometry causes the image receptor to be positioned at various angl...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2219090
更新日期：2006-08-01 00:00:00
abstract：PURPOSE:IAEA TRS-398 notes that cylindrical ionization chambers are preferred for reference proton dosimetry. If a cylindrical ionization chamber is used in a phantom to measure the dose as a function of depth, the effective point of measurement (EPOM) must be taken into account. IAEA TRS-398 recommends a displacement ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4921617
更新日期：2015-07-01 00:00:00
abstract：:A fast method of seed matching and reconstruction in prostate brachytherapy is proposed. Previous approaches have required all seeds to be matched with all other seeds in other projections. The fast cross-projection algorithm for the reconstruction of seeds (Fast-CARS) allows for matching of a given seed with a subset...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1489044
更新日期：2002-07-01 00:00:00
abstract：:In previous work it has been shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, it is demonstrated that an artificial neural network (ANN) trained on a s...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597586
更新日期：1995-05-01 00:00:00
abstract：:Permanent implants of 125I seeds at Memorial Sloan-Kettering Cancer Center are performed by the method of "dimension averaging" to determine the total activity to be implanted; that is, the activity (in mCi) is taken to be five times the average dimension (in cm) of the target region. A nomograph has recently been dev...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594269
更新日期：1976-01-01 00:00:00
abstract：PURPOSE:It is estimated that 7% of women in the western world will develop palpable breast cysts in their lifetime. Even though cysts have been correlated with risk of developing breast cancer, many of them are benign and do not require follow-up. We develop a method to discriminate benign solitary cysts from malignant...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12110
更新日期：2017-03-01 00:00:00
