Abstract:
:Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM3), a novel method for prostate motion reconstruction in volumetric modulated arc therapy. The purpose of this method is to reconstruct in-treatment prostate motion trajectory using projected positions of implanted fiducial markers measured in kV x-ray projection images acquired during treatment delivery. We formulated this task as a quadratic optimization problem. The objective function penalized the distance from the reconstructed 3D position of each fiducial marker to the corresponding straight line, defined by the x-ray projection of the marker. Rigid translational motion of the prostate and motion smoothness along the temporal dimension were assumed and incorporated into the optimization model. We tested the motion reconstruction method in both simulation and phantom experimental studies. We quantified the accuracy using 3D normalized root-mean-square (RMS) error defined as the norm of a vector containing ratios between the absolute RMS errors and corresponding motion ranges in three dimensions. In the simulation study with realistic prostate motion trajectories, the 3D normalized RMS error was on average [Formula: see text] (range from [Formula: see text] to [Formula: see text]). In an experimental study, a prostate phantom was driven to move along a realistic prostate motion trajectory. The 3D normalized RMS error was [Formula: see text]. We also examined the impact of the model parameters on reconstruction accuracy, and found that a single set of parameters can be used for all the tested cases to accurately reconstruct the motion trajectories. The motion trajectory derived by PM3 may be incorporated into novel strategies, including 4D dose reconstruction and adaptive treatment replanning to address motion-induced dose deviation.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Chi Y,Rezaeian NH,Shen C,Zhou Y,Lu W,Yang M,Hannan R,Jia Xdoi
10.1088/1361-6560/aa6e37subject
Has Abstractpub_date
2017-07-07 00:00:00pages
5509-5530issue
13eissn
0031-9155issn
1361-6560journal_volume
62pub_type
杂志文章abstract::In vitro dielectric properties of ageing porcine tissues were measured in the frequency range of 50 MHz-20 GHz, and the total combined uncertainties of the measurements were assessed. The results show statistically significant reduction with age in both permittivity and conductivity of 10 out of 15 measured tissues. A...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/2/004
更新日期:2009-01-21 00:00:00
abstract::Respiratory gating can reduce the apparent respiratory motion during imaging and treatment; however, residual motion within the gating window remains. Respiratory training can improve respiratory reproducibility and, therefore, the efficacy of respiratory-gated radiotherapy. This study was conducted to determine wheth...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/20/015
更新日期:2006-10-21 00:00:00
abstract::For proton therapy, an accurate conversion of CT HU to relative stopping power (RSP) is essential. Validation of the conversion based on real tissue samples is more direct than the current practice solely based on tissue substitutes and can potentially address variations over the population. Based on a novel dose exti...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa782c
更新日期:2017-06-23 00:00:00
abstract::The goals of this study were (1) to characterize the optical artefacts affecting measurement accuracy in a volumetric liquid scintillator detector, and (2) to develop methods to correct for these artefacts. The optical artefacts addressed were photon scattering, refraction, camera perspective, vignetting, lens distort...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/1/23
更新日期:2014-01-06 00:00:00
abstract::Calculating the dynamic properties of magnetization of single-domain particles is of great importance for the tomographic imaging modality known as magnetic particle imaging (MPI). Although the assumption of instantaneous thermodynamic equilibrium (Langevin function) after application of time-dependent magnetic fields...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aaa186
更新日期:2018-01-22 00:00:00
abstract::The treatment of lung cancer with radiation therapy is hindered by respiratory motion. Real-time adjustments to compensate for this motion are hampered by mechanical system latencies and imaging-rate restrictions. To better understand tumour motion behaviour for adaptive image-guided radiation therapy of lung cancer, ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/12/005
更新日期:2010-06-21 00:00:00
abstract::Irradiation of moving targets using a scanned ion beam can cause clinically intolerable under- and overdosages within the target volume due to the interplay effect. Several motion mitigation techniques such as gating, beam tracking and rescanning are currently investigated to overcome this restriction. To enable detai...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/8/2235
更新日期:2012-04-21 00:00:00
abstract::In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 microm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity....
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/24/003
更新日期:2006-12-21 00:00:00
abstract::Monte Carlo simulation with PENELOPE (version 2003) is applied to calculate Leksell Gamma Knife dose distributions for heterogeneous phantoms. The usual spherical water phantom is modified with a spherical bone shell simulating the skull and an air-filled cube simulating the frontal or maxillary sinuses. Different sim...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/23/018
更新日期:2005-12-07 00:00:00
abstract::Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/11/3273
更新日期:2012-06-07 00:00:00
abstract::Characterization of both malignant and benign lesions in the female breast is presented as the result of a clinical study that involved more than 190 subjects in the framework of the OPTIMAMM European project. All the subjects underwent optical mammography, by means of a multi-wavelength time-resolved mammograph, in t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/11/004
更新日期:2005-06-07 00:00:00
abstract::We propose a hybrid multiobjective (MO) evolutionary optimization algorithm (MOEA) for intensity-modulated radiotherapy inverse planning and apply it to optimize the number of incident beams, their orientations and intensity profiles. The algorithm produces a set of efficient solutions, which represent different clini...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/5/007
更新日期:2004-03-07 00:00:00
abstract::This study verifies the concept of the super-omni wedge by validating its equations for effective wedge orientation and wedge angle and by comparing the dose distributions it produces with those produced by other wedge techniques. To validate the equations, we calculated dose distributions for 20 combinations of wedge...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/46/9/313
更新日期:2001-09-01 00:00:00
abstract::Proton therapy is very sensitive to daily density changes along the pencil beam paths. The purpose of this study is to develop and evaluate an automated method for adaptation of IMPT plans to compensate for these daily tissue density variations. A two-step restoration method for 'densities-of-the-day' was created: (1)...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5c12
更新日期:2017-06-07 00:00:00
abstract::In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/5/315
更新日期:1999-05-01 00:00:00
abstract::The use of thermographic techniques has increased as infrared detector technology has evolved and improved. For laser-tissue interactions, thermal cameras have been used to monitor the thermal response of tissue to pulsed and continuous wave irradiation. It is important to note that the temperature indicated by the th...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/45/2/319
更新日期:2000-02-01 00:00:00
abstract::Quantitative Yttrium-90 ((90)Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging has shown great potential to provide reliable estimates of (90)Y activity distribution for targeted radionuclide therapy dosimetry applications. One factor that potentially affects the reliability of the activity ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/12/3711
更新日期:2012-06-21 00:00:00
abstract::We couple standardized low-resolution electromagnetic tomography, an inverse solution for electroencephalography (EEG) and the common spatial pattern, which is here conceived as a data-driven beamformer, to classify the benchmark BCI (brain-computer interface) competition 2003, data set IV. The data set is from an exp...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/8/002
更新日期:2006-04-21 00:00:00
abstract::In recent years, optical techniques based on diffusion approximation have demonstrated their ability to gain rich spectral information about bone. However, these methods normally assume homogeneity, while cancellous bone and marrow form a highly heterogeneous two-phase medium. This paper studies the limitations of thi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/17/003
更新日期:2010-09-07 00:00:00
abstract::Monitoring the spatio-temporal characteristics of microcirculation is crucial for studying the functional activities of biotissue and the mechanism of disease. However, conventional methods used to measure blood flow suffer from limited spatial resolution or the injection of exogenous substances or the need of scannin...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/7/020
更新日期:2004-04-07 00:00:00
abstract::Densitometric quantification of coronary artery stenoses in angiographic images can be problematic for two reasons: (i) the x-rays are inadequately oriented with respect to the vessel segments of interest at image acquisition; (ii) non-linear effects due for instance to beam hardening, scattered radiation and veiling ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/12/011
更新日期:1997-12-01 00:00:00
abstract::The quality of thorax and pelvis transmission scans and therefore of attenuation correction in PET depends on patient thickness and transmission rod source strength. The purpose of the present study was to assess the feasibility of using count-based transmission scans, thereby guaranteeing more consistent image qualit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/4/n01
更新日期:2004-02-21 00:00:00
abstract::Statistically based iterative image reconstruction methods have been developed for emission tomography. One important component in iterative image reconstruction is the system matrix, which defines the mapping from the image space to the data space. Several groups have demonstrated that an accurate system matrix can i...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/14/007
更新日期:2005-07-21 00:00:00
abstract::Investigate 3D (spatial and temporal) convolutional neural networks (CNNs) for real-time on-the-fly magnetic resonance imaging (MRI) reconstruction. In particular, we investigated the applicability of training CNNs on a patient-by-patient basis for the purpose of lung tumor segmentation. Data were acquired with our 3 ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab408e
更新日期:2019-09-23 00:00:00
abstract::The reproducibility of polyacrylamide gel (PAG) dosimetry has been evaluated when used to verify two radiotherapy treatment plans of increasing complexity. The plans investigated were a three-field coplanar arrangement, using the linac jaws for field shaping, and a four-field, conformal, non-coplanar plan using precis...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/45/5/309
更新日期:2000-05-01 00:00:00
abstract::Numerical computations are used to evaluate electric field dosimetry for high-resolution anatomically based inhomogeneous models of a human male child, and male and female rats and mice, under exposure to 60 Hz uniform magnetic field sources of three perpendicular orientations. The goal is to compare the child data to...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/14/313
更新日期:2002-07-21 00:00:00
abstract::Determining a multidimensional velocity field within microscale opaque fluid flows is needed in areas such as microfluidic devices, biofluid mechanics and hemodynamics research in animal studies. The ultrasonic particle image velocimetry (EchoPIV) technique is appropriate for measuring opaque flows by taking advantage...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/20/003
更新日期:2010-10-21 00:00:00
abstract::Monolithic scintillation detectors for positron emission tomography and single-photon emission computed tomography (SPECT) imaging have many advantages over pixelated detectors. The use of monolithic crystals allows for reducing the scintillator cost per unit volume and increasing the sensitivity along with the energy...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/14/4807
更新日期:2013-07-21 00:00:00
abstract::The aim of the present work was to implement the kinetics of cisplatin into a previously developed tumour growth model and to simulate the combined cisplatin-radiotherapy treatment with the emphasis on time sequencing and scheduling of drug and radiation. An investigation into whether the effect of cisplatin-radiation...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/15/002
更新日期:2006-08-07 00:00:00
abstract::The cerebral arteries are difficult to reproduce from first principles, featuring interwoven territories, and intricate layers of grey and white matter with differing metabolic demand. The aim of this study was to identify the ideal configuration of arteries required to sustain an entire brain hemisphere based on mini...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab2479
更新日期:2019-06-21 00:00:00