Abstract:
:Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse rawdata and provides more stable results than volume-to-volume approaches. By applying the proposed registration approach to low dose tomographic fluoroscopy it is possible to improve the temporal resolution and thus to increase the robustness of low dose tomographic fluoroscopy.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Flach B,Brehm M,Sawall S,Kachelrieß Mdoi
10.1088/0031-9155/59/24/7865subject
Has Abstractpub_date
2014-12-21 00:00:00pages
7865-87issue
24eissn
0031-9155issn
1361-6560journal_volume
59pub_type
杂志文章abstract::Does the posture of a patient have an effect on the organ and tissue absorbed doses caused by x-ray examinations? This study aims to find the answer to this question, based on Monte Carlo (MC) simulations of commonly performed x-ray examinations using adult phantoms modelled to represent humans in standing as well as ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/15/014
更新日期:2010-08-07 00:00:00
abstract::Estimation of a set of parameters that describe the geometry of the cone-beam computed tomography system plays an important role in the geometrical calibration. In the calibration process, the helical phantom consisting of spherical markers arranged on a helical trajectory has been widely applied. To directly determin...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/19/5667
更新日期:2014-10-07 00:00:00
abstract::The National Physical Laboratory (NPL) provides a high-energy photon calibration service using 4-19 MV x-rays and 60Co gamma-radiation for secondary standard dosemeters in terms of absorbed dose to water. The primary standard used for this service is a graphite calorimeter and so absorbed dose calibrations must be con...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/3/306
更新日期:2002-02-07 00:00:00
abstract::The purpose of this study was to determine the performance of a single lutetium oxy-orthosilicate (LSO) crystal layer High Resolution Research Tomograph (HRRT) positron emission tomography (PET) scanner. The HRRT is a high resolution PET scanner designed for human brain and small animal imaging. The scanner consists o...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/48/4/302
更新日期:2003-02-21 00:00:00
abstract::Registration of different imaging modalities such as CT, MRI, functional MRI (fMRI), positron (PET) and single photon (SPECT) emission tomography is used in many clinical applications. Determining the quality of any automatic registration procedure has been a challenging part because no gold standard is available to e...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/10/N01
更新日期:2005-05-21 00:00:00
abstract::The implementation of two algorithms for calculating dose distributions for radiation therapy treatment planning of intermediate energy proton beams is described. A pencil kernel algorithm and a depth penetration algorithm have been incorporated into a commercial three dimensional treatment planning system (Helax-TMS,...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/45/1/302
更新日期:2000-01-01 00:00:00
abstract::Short- and long-term side effects following the treatment of cancer with radiation are strongly related to the amount of dose deposited to the healthy tissue surrounding the tumor. The characterization of the radiation field outside the planned target volume is the first step for estimating health risks, such as devel...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/8/2111
更新日期:2014-04-21 00:00:00
abstract::A method will be described for determining the centre of rotation of a mechanically scanned reflection ultrasound computed tomography system. It is based on the principle of obtaining opposing images of a test object containing many point targets. The method is automatic in the sense that the centre of rotation is cal...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/39/12/017
更新日期:1994-12-01 00:00:00
abstract::Optically stimulated luminescent dosimeters (OSLDs) are becoming increasingly popular for measuring an absorbed dose in clinical radiotherapy. OSLDs have known energy dependence, and this is accounted for by either calibrating the OSLD with a specific nominal energy, or using a standard energy correction factor to acc...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/9/2505
更新日期:2012-05-07 00:00:00
abstract::To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5452
更新日期:2017-04-21 00:00:00
abstract::Sparse phased array ultrasound transducers with millimetre length scale elements have previously been proposed for generating hyperthermia but not for imaging. Numerical simulation with a pseudospectral solver was used to investigate: (a) how the position of the maximum pressure in the focal region changed with elemen...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aace07
更新日期:2018-07-16 00:00:00
abstract::Dynamic PET image reconstruction is a challenging issue due to the low SNR and the large quantity of spatio-temporal data. We propose a robust state-space image reconstruction (SSIR) framework for activity reconstruction in dynamic PET. Unlike statistically-based frame-by-frame methods, tracer kinetic modeling is inco...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/8/010
更新日期:2011-04-21 00:00:00
abstract::Uncemented prosthetic joint implants used in orthopaedic surgery are usually coated with a porous surface to encourage bone ingrowth. Better contact between the endosteal bone and the porous surface improves ingrowth, and such contact may be increased if the joint further subsides into position in the first weeks foll...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/38/2/009
更新日期:1993-02-01 00:00:00
abstract::New values of the factors required to convert the reading of a radiation dosemeter calibrated in terms of air kerma (or exposure) into absorbed dose to water for medium-energy x-radiation were given in a code of practice published by the IAEA in 1987. These are not considered to possess sufficient support from other s...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/36/8/001
更新日期:1991-08-01 00:00:00
abstract::A semi-empirical theory has been derived that relates the aluminum equivalence of various materials used in diagnostic radiology to their attenuation coefficients. The dependence of the aluminum hardness (AHE) and attenuation (AAE) equivalent on the beam quality is described in terms of effective energy. This 'aluminu...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/31/12/006
更新日期:1986-12-01 00:00:00
abstract::A technique is presented to allow a breathing pattern to be obtained from any multi-slice CT, cone-beam or other series of sequential chest x-ray image sets. The technique requires no extra signals to be recorded and does not need specific external or internal oscillating structures to be visible in the field of view....
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/16/003
更新日期:2009-08-21 00:00:00
abstract::Recent developments in the technique of constant infusion and in emission computed tomography have provided a new method for quantitative regional flow measurements. This paper re-examines critically the theoretical relationship between flow and radioactivity during constant infusion of short-lived isotopes. Sensitivi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/24/6/005
更新日期:1979-11-01 00:00:00
abstract::A method for simulating spot-scanned delivery to a moving tumour was developed which uses patient-specific image and plan data. The magnitude of interplay effects was investigated for two patient cases under different fractionation and respiratory motion variation scenarios. The use of volumetric rescanning for motion...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/20/003
更新日期:2011-10-21 00:00:00
abstract::Simultaneous near-infrared spectroscopy (NIRS) and magnetic resonance imaging (MRI) were used to investigate the correlation between tumour vascular oxygenation and tissue oxygen tension dynamics in rat breast 13762NF tumours with respect to hyperoxic gas breathing. NIRS directly detected global variations in the oxyg...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/1/004
更新日期:2006-01-07 00:00:00
abstract::Images of the human retina are routinely used in clinical practice for the diagnosis and management of eye disease. Increased permeability of retinal blood vessels, which is a clinically significant feature, can be visualized with a process known as fluorescein angiography as leakage of fluorescence dye into the surro...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/1/021
更新日期:1999-01-01 00:00:00
abstract::Two experimental investigations of the electromagnetic method to measure body composition are presented. In the first experiment, the impedance of a single-loop transmitting antenna, located at the centre of a 150 m helical receiving coil, was observed to have a sharp minimum at 2.40 MHz. The impedance of the antenna ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/40/4/011
更新日期:1995-04-01 00:00:00
abstract::The Monte Carlo method is the most accurate method for radiotherapy dose calculations, if used correctly. However, any Monte Carlo dose calculation is burdened with statistical noise. In this paper, denoising of Monte Carlo dose distributions with a three-dimensional adaptive anisotropic diffusion method was investiga...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/48/17/303
更新日期:2003-09-07 00:00:00
abstract::Distributions of linear pathlength measurements have been utilized in skeletal dosimetry of internally emitted short-range particles for over 30 years. This work reviews the methods for coupling these distributions to range-energy data. A revised methodology is presented for handling the insertion of the additional do...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/9/004
更新日期:2011-05-07 00:00:00
abstract::The dielectric properties of glycerol, propylene glycol, ethylene glycol and dimethyl sulphoxide have been measured in various aqueous concentrations generally sufficient to allow supercooling rather than freezing. The temperature range investigated is from -80 degrees C to +20 degrees C and the frequency range is 100...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/10/014
更新日期:1996-10-01 00:00:00
abstract::Dose factors for locations within a tissue-filled cylindrical cavity bounded by an infinite medium of bone labelled with an alpha-emitter are calculated by means of a Monte Carlo procedure. The calculational approach is general and allows us to determine dose factors for specific distances or target volumes defined by...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/34/3/007
更新日期:1989-03-01 00:00:00
abstract::Intensity modulated proton radiotherapy (IMPT) can reduce the dose to critical structures by optimizing the distribution and intensity of individual pencil beams. The IMPT can be delivered by dynamically scanning a pencil beam with variable intensity and energy across the tumor target volume. The lateral penumbra of a...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/6/016
更新日期:2008-03-21 00:00:00
abstract::Refraction contrast of simple objects obtained using diffraction enhanced imaging (DEI) was studied and compared to conventional radiographic contrast. Lucite cylinders and nylon wires were imaged using monochromatic synchrotron radiation at the National Synchrotron Light Source (http://nslsweb. nsls.bnl.gov/nsls/Defa...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/48/3/304
更新日期:2003-02-07 00:00:00
abstract::We have measured the bulk optical properties of healthy female breast tissues in vivo in the parallel plate, transmission geometry. Fifty-two volunteers were measured. Blood volume and blood oxygen saturation were derived from the optical property data using a novel method that employed a priori spectral information t...
journal_title:Physics in medicine and biology
pub_type: 临床试验,杂志文章
doi:10.1088/0031-9155/47/16/302
更新日期:2002-08-21 00:00:00
abstract::The dynamic magnetization of immobilized spherical single-domain magnetic nanoparticles (MNPs) with uniaxial or cubic magnetocrystalline anisotropy was studied computationally by executing simulations based on the Landau-Lifshitz-Gilbert (LLG) equation. For situations when a static magnetic field was suddenly applied ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab5b83
更新日期:2020-01-17 00:00:00
abstract::Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/18/009
更新日期:2010-09-21 00:00:00