Abstract:
PURPOSE:The limited-angle intrafractional verification (LIVE) system was developed to track tumor movement during stereotactic body radiation therapy (SBRT). However, the four-dimensional (4D) MV/kV imaging procedure results in additional radiation dose to patients. This study is to quantify imaging radiation dose from optimized MV/kV image acquisition in the LIVE system and to determine if it exceeds the American Association of Physicists in Medicine Task Group Report 180 image dose threshold. METHODS:TrueBeam™ platform with a fully integrated system for image guidance was studied. Monte Carlo-simulated kV and MV beams were calibrated and then used as incident sources in an EGSnrc Monte Carlo dose calculation in a CT image-based patient model. In three representative lung SBRT treatments evaluated in this study, tumors were located in the patient's posterior left lung, mid-left lung, and right upper lung. The optimized imaging sequence comprised of arcs ranging from 2 to 7, acquired between adjacent three-dimensional (3D)/IMRT beams, with multiple simultaneous kV (125 kVp) and MV (6 MV) image projections in each arc, for different optimization scenarios. The MV imaging fields were generally confined to the treatment target while kV images were acquired with a normal open field size with a full bow-tie filter. RESULTS:In a seven-arc acquisitions case (highest imaging dose scenario), the maximum kV imaging doses to 50% of the tissue volume (D50 from DVHs), for spinal cord, right lung, heart, left lung, and the target, were 0.4, 0.4, 0.6, 0.7, and 1.4 cGy, respectively. The corresponding MV imaging doses were 0.1 cGy to spinal cord, right lung, heart, and left lung, and 11 cGy to target. In contrast, the maximum radiation dose from two cases treated with two Volumetric-Modulated Arc Therapy (VMAT) fields and two-arc image acquisitions is approximately 30% of that of the seven-arc acquisition. CONCLUSIONS:We have evaluated the additional radiation dose resulting from optimized LIVE system MV/kV image acquisitions in two best (least imaging dose) and one worst (highest imaging dose) lung SBRT treatment scenarios. The results show that these MV/kV imaging doses are comparable to those resulting from current imaging procedures used in Image-Guided Radiation Therapy (IGRT) and are within the dose threshold of 5% target dose as recommended by the AAPM TG-180 report.
journal_name
Med Physjournal_title
Medical physicsauthors
Ding GX,Zhang Y,Ren Ldoi
10.1002/mp.13511subject
Has Abstractpub_date
2019-06-01 00:00:00pages
2709-2715issue
6eissn
0094-2405issn
2473-4209journal_volume
46pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:To improve image quality and reduce imaging dose in CBCT for radiation therapy applications and to realize near real-time image reconstruction based on use of a fast convergence iterative algorithm and acceleration by multi-GPUs. METHODS:An iterative image reconstruction that sought to minimize a weighted leas...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735747
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Ultrasound-induced mild hyperthermia has advantages for noninvasive, localized and controlled drug delivery. In this study, a tissue-mimicking agarose-based phantom with a thermally sensitive indicator was developed for studying the spatial drug delivery profile using ultrasound-induced mild hyperthermia. METH...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4813299
更新日期:2013-08-01 00:00:00
abstract:PURPOSE:Identification of calcifications and hemorrhages is essential for the etiological diagnosis of cerebral lesions. The purpose of this work was to develop a robust method for characterization of para- and diamagnetic intracerebral lesions based on clinical gradient-echo magnetic resonance phase data acquired at 1...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3481505
更新日期:2010-10-01 00:00:00
abstract::Significant advances have been made in recent years to improve photon dose calculation. However, accurate prediction of dose perturbation effects near the interfaces of different media, where charged particle equilibrium is not established, remain unsolved. Furthermore, changes in atomic number, which affect the multi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597611
更新日期:1995-07-01 00:00:00
abstract:PURPOSE:For the purpose of size-specific dose estimation, information regarding patient attenuation is required. The purpose of this work is to describe a method for measuring patient attenuation and expressing the results in terms of a water cylinder, with cross sectional area A(w), which would absorb the same average...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4754303
更新日期:2012-11-01 00:00:00
abstract::The purpose of the present study is to characterize electron contamination in photon beams in different clinical situations. Variations with field size, beam modifier (tray, shaping block) and source-surface distance (SSD) were studied. Percentage depth dose measurements with and without a purging magnet and replacing...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1895793
更新日期:2005-05-01 00:00:00
abstract::In this investigation, five experimental data sets are used to evaluate the ability of the EGSnrc Monte Carlo code to calculate the change in chamber response associated with changes in wall material and cavity dimension at 60Co energies. Calculations of the ratios of response per unit mass of air as a function of cav...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3013701
更新日期:2008-12-01 00:00:00
abstract::The geometric accuracy and precision of an image-guided treatment system were assessed. Image guidance is performed using an x-ray volume imaging (XVI) system integrated with a linear accelerator and treatment planning system. Using an amorphous silicon detector and x-ray tube, volumetric computed tomography images ar...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2143141
更新日期:2006-01-01 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 dosimetry of 192Ir linear sources with a commercial treatment planning computer system has been evaluated. Reference dose rate data were selected from the literature and normalized in a manner consistent with our clinical and dosimetric terminology. The results of the computer calculations are compared to the refe...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595685
更新日期:1985-09-01 00:00:00
abstract:PURPOSE:The aim of this work is to investigate the predictive power of a common conventional intensity modulated radiation therapy (IMRT) quality assurance (QA) performance metric, the gamma passing rate (%GP), through the analysis of the sensitivity and of the correlation between %GP and different dose discrepancies b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4767763
更新日期:2012-12-01 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:PURPOSE:X-ray fluorescence (XRF) is a promising technique with sufficient specificity and sensitivity for identifying and quantifying features in small samples containing high atomic number (Z) materials such as iodine, gadolinium, and gold. In this study, the feasibility of applying XRF to early breast cancer diagnosi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4863510
更新日期:2014-03-01 00:00:00
abstract::In computer simulations of x-ray CT systems one can either use continuous geometrical descriptions for phantoms or a voxelized representation. The voxelized approach allows arbitrary phantoms to be defined without being confined to geometrical shapes. The disadvantage of the voxelized approach is that inherent errors ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1461841
更新日期:2002-04-01 00:00:00
abstract:PURPOSE:A high resolution, water equivalent, optical and passive x-ray dosimeter has been constructed using plastic scintillator and optical fiber. This dosimeter has a peak edge-on spatial resolution of 100 μm in one dimension, with a 10 μm resolution dosimeter under investigation. The dosimeter design has a potential...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12209
更新日期:2017-05-01 00:00:00
abstract::We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagn...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595878
更新日期:1986-05-01 00:00:00
abstract:PURPOSE:To build a statistical model to quantitatively correlate the anatomic features of structures and the corresponding dose-volume histogram (DVH) of head and neck (HN) Tomotherapy (Tomo) plans. To study if the model built upon one intensity modulated radiation therapy (IMRT) technique (such as conventional Linac) ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4828788
更新日期:2013-12-01 00:00:00
abstract::The use of electronic portal imaging devices (EPIDs) is a promising method for the dosimetric verification of external beam, megavoltage radiation therapy-both pretreatment and in vivo. In this study, a previously developed EPID back-projection algorithm was modified for IMRT techniques and applied to an amorphous sil...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2147744
更新日期:2006-02-01 00:00:00
abstract::The ability of Leksell GammaPlan to perform stereotactic space localizations with image sets where there is misalignment of the patient's head (stereotactic frame and fiducial apparatus) relative to the computed tomography (CT) scanner coordinate system was studied. Misalignment is sometimes necessary for patient comf...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2179751
更新日期:2006-04-01 00:00:00
abstract:PURPOSE:To estimate and correct for the volume averaging effect which results from the intra-chamber dose gradients when a Farmer ionization chamber (IC) is used for reference dosimetry in flattening-filter-free (FFF) MV photon beams. METHODS:An intra-chamber dose gradients correction factor (kicdg) to the charge read...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4958960
更新日期:2016-08-01 00:00:00
abstract::Variation of the photoactivation rate across radiation fields of three different bremsstrahlung beams of two medical accelerators has been measured, making use of the photonuclear reactions in natural indium probes: 115In(y,y')115mIn and 115In(y,n)114mIn. The third nuclear reaction, 115In(n,y)116mIn, was used to detec...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598558
更新日期:1999-04-01 00:00:00
abstract::The focal spot of a linear accelerator is often considered to have a fully stable position. In practice, however, the beam control loop of a linear accelerator needs to stabilize after the beam is turned on. As a result, some motion of the focal spot might occur during the start-up phase of irradiation. When acquiring...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1576229
更新日期:2003-06-01 00:00:00
abstract::A method to correct for geometric image distortion in the x-ray imaging chain, so-called dewarping, has been developed. A global two-dimensional polynomial model of which the degree is optimized is used. The performance of the method has been tested in a number of experiments using images of a plate with a 1 cm spaced...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598101
更新日期:1997-12-01 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::Current MRI nonuniformity correction techniques are reviewed and investigated. Many approaches are used to remedy this artifact, but it is not clear which method is the most appropriate in a given situation, as the applications have been with different MRI coils and different clinical applications. In this work four w...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.598357
更新日期:1998-09-01 00:00:00
abstract::The authors present an alternative approach to inverse planning optimization and apply it to volumetric modulated are therapy (VMAT) in one rotation with a prior knowledge about the type of leaf motions. The optimization is based on the projection theorem in inner product spaces. MLC motion is directly considered in t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3173815
更新日期:2009-08-01 00:00:00
abstract:PURPOSE:Micro-CT is widely used for small animal imaging in preclinical studies of cardiopulmonary disease, but further development is needed to improve spatial resolution, temporal resolution, and material contrast. We present a technique for visualizing the changing distribution of iodine in the cardiac cycle with du...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4736809
更新日期:2012-08-01 00:00:00
abstract:PURPOSE:The aim of this work was to provide a novel description of how the radiotherapy community configures treatment planning system (TPS) radiation beam models for clinically used treatment machines. Here we describe the results of a survey of self-reported TPS beam modeling parameter values across different C-arm l...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13892
更新日期:2020-01-01 00:00:00
abstract::The immediate goal of clinically based x-ray-transmission computed tomography (CT) is to provide a measurement of the x-ray linear attenuation coefficient in cross section with the ultimate goal of impacting on patient management and care. To do this with the accuracy needed for clinical goals requires the careful int...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.594381
更新日期:1977-03-01 00:00:00
abstract::Knowledge of the relative intensity distribution at the patient's surface is essential for pencil beam calculations of three-dimensional dose distributions for arbitrarily shaped electron beams. To calculate the relative intensity distribution, the spatial spread resulting from angular spread is convolved with a two-d...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596252
更新日期:1988-03-01 00:00:00