A fast 4D IMRT/VMAT planning method based on segment aperture morphing.

abstract：PURPOSE:Quantification of body composition plays an important role in many clinical and research applications. Radiologic imaging techniques such as Dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) imaging make accurate quantification of the body composition possibl...

journal_title：Medical physics

authors： Liu T,Udupa JK,Miao Q,Tong Y,Torigian DA

更新日期：2019-03-01 00:00:00

abstract：PURPOSE:Couch and MLC tracking are two promising methods for real-time motion compensation during radiation therapy. So far, couch and MLC tracking experiments have mainly been performed by different research groups, and no direct comparison of couch and MLC tracking of volumetric modulated arc therapy (VMAT) plans has...

journal_title：Medical physics

authors： Hansen R,Ravkilde T,Worm ES,Toftegaard J,Grau C,Macek K,Poulsen PR

更新日期：2016-05-01 00:00:00

abstract：:Monte Carlo simulation dosimetry is used to compare 169Yb to 192Ir for breast high dose rate (HDR) brachytherapy applications using multiple catheter implants. Results for bare point sources show that while 169Yb delivers a greater dose rate per unit air kerma strength at the radial distance range of interest to brach...

journal_title：Medical physics

authors： Lymperopoulou G,Papagiannis P,Angelopoulos A,Karaiskos P,Georgiou E,Baltas D

更新日期：2006-12-01 00:00:00

abstract：PURPOSE:The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). METHODS:A cust...

journal_title：Medical physics

authors： Sieren JP,Newell JD,Judy PF,Lynch DA,Chan KS,Guo J,Hoffman EA

更新日期：2012-09-01 00:00:00

abstract：:Studies suggest that clinical outcomes are improved in repeat trigeminal neuralgia (TN) Gamma Knife radiosurgery if a different part of the nerve from the previous radiosurgery is treated. The MR images taken in the first and repeat radiosurgery need to be coregistered to map the first radiosurgery volume onto the sec...

journal_title：Medical physics

authors： Li X,Zhang P,Brisman R,Kutcher G

更新日期：2005-07-01 00:00:00

abstract：PURPOSE:To develop an individually optimized contrast-enhanced (CE) 4D-computed tomography (CT) for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA). METHODS:Ten PDA patients were enrolled. Each underwent three CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT ...

journal_title：Medical physics

authors： Choi W,Xue M,Lane BF,Kang MK,Patel K,Regine WF,Klahr P,Wang J,Chen S,D'Souza W,Lu W

更新日期：2016-10-01 00:00:00

abstract：PURPOSE:It is important for many quantitative brain studies to label meaningful anatomical regions in MR brain images. However, due to high complexity of brain structures and ambiguous boundaries between different anatomical regions, the anatomical labeling of MR brain images is still quite a challenging task. In many ...

journal_title：Medical physics

authors： Ma G,Gao Y,Wu G,Wu L,Shen D

更新日期：2016-02-01 00:00:00

abstract：:An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are ...

journal_title：Medical physics

authors： Rice JR,Milbrandt RH,Madsen EL,Frank GR,Boote EJ,Blechinger JC

更新日期：1998-07-01 00:00:00

abstract：PURPOSE:To reduce image noise and radiation dose in Digital Breast Tomosynthesis (DBT) reconstructions. METHODS:A retrospective study was performed on clinical data sets acquired at a normal dose with Hologic Selenia Dimensions DBT systems. The Prior Image Constrained Compressed Sensing (PICCS) algorithm was used to r...

journal_title：Medical physics

authors： Garrett J,Tang J,Zhang Y,Ruth C,Jing Z,Chen GH

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To propose a method to calculate the tissue phantom ratio (TPR) using the depth dose and to compare the proposed method with two other methods. METHODS:An analytical dose model from Bjärngard was used to describe the depth dose and the TPR. The parameters of the model were derived from depth dose measurements,...

journal_title：Medical physics

authors： Ramos Garcia LI,Almansa JF

更新日期：2011-05-01 00:00:00

abstract：PURPOSE:The aim of this study was to investigate the effect of scatter and its correction on kinetic parameters in dynamic brain positron emission tomography (PET) tumor imaging. The 2-tissue compartment model was used, and two different reconstruction methods and two scatter correction (SC) schemes were investigated. ...

journal_title：Medical physics

authors： Häggström I,Schmidtlein CR,Karlsson M,Larsson A

更新日期：2014-11-01 00:00:00

abstract：PURPOSE:Diabetic retinopathy (DR) is one of the most widespread causes of preventable blindness in the world. The most dangerous stage of this condition is proliferative DR (PDR), in which the risk of vision loss is high and treatments are less effective. Fractal features of the retinal vasculature have been previously...

journal_title：Medical physics

authors： Orlando JI,van Keer K,Barbosa Breda J,Manterola HL,Blaschko MB,Clausse A

更新日期：2017-12-01 00:00:00

abstract：:Spectrally resolved bioluminescence optical tomography is an approach to recover images of, for example, Luciferase activity within a volume using multiwavelength emission data from internal bioluminescence sources. The underlying problem of uniqueness associated with nonspectrally resolved intensity-based bioluminesc...

journal_title：Medical physics

authors： Dehghani H,Davis SC,Pogue BW

更新日期：2008-11-01 00:00:00

abstract：:To account for clinical divergent and polychromatic photon beams, we have developed kernel tilting and kernel hardening correction methods for convolution dose calculation algorithms. The new correction methods were validated by Monte Carlo simulation. The accuracy and computation time of the our kernel tilting and ke...

journal_title：Medical physics

authors： Liu HH,Mackie TR,McCullough EC

更新日期：1997-11-01 00:00:00

abstract：PURPOSE:Discuss optimised Accelerated Partial Breast Irradiation (APBI) using a Strut-Adjused Volume Implant (SAVI) applicator for patients with implanted pacemeker, without overdosing or relocating the pacemaker. METHODS:A right breast cancer patient with an in situ pacemaker (Medtronic model ADDR01) on the right sid...

journal_title：Medical physics

authors： Jacob D,Strasser J

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The variable resolution x-ray (VRX) CT scanner provides substantial improvement in the spatial resolution by matching the scanner's field of view (FOV) to the size of the object being imaged. Intercell x-ray cross-talk is one of the most important factors limiting the spatial resolution of the VRX detector. In ...

journal_title：Medical physics

authors： Arabi H,Asl AR,Ay MR,Zaidi H

更新日期：2011-03-01 00:00:00

abstract：PURPOSE:To balance dose reduction and image registration accuracy in breast setup imaging. In particular, the authors demonstrate the relationship between scan angle and dose delivery for cone beam tomosynthesis (CBTS) when employed for setup verification of breast cancer patients with surgical clips. METHODS:The dose...

journal_title：Medical physics

authors： Winey BA,Zygmanski P,Cormack RA,Lyatskaya Y

更新日期：2010-08-01 00:00:00

abstract：PURPOSE:To quantify the needle tip detection errors in ultrasound images due to bevel-tip orientation in relation to the location on template grid. METHODS:Transrectal ultrasound (TRUS) system (BK Medical) with physical template grid and 18-gauge bevel-tip (20-deg beveled angle) brachytherapy needle (Bard Medical, Cov...

journal_title：Medical physics

authors： Leu S,Ruiz B,Podder T

更新日期：2012-06-01 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

authors： Xu XL,Liow JS,Strother SC

更新日期：1993-11-01 00:00:00

abstract：:When a catheter is inserted through an artery, the wall shear stress increases and the secondary flow exhibits an increased number of instantaneous vortices. These effects become more evident when the annular gap between the catheter and the artery becomes more narrow. Accordingly it is suggested that these factors ma...

journal_title：Medical physics

authors： Karahalios GT

更新日期：1990-09-01 00:00:00

abstract：:We propose a new starting point for comparing planar dose distributions using a Jacobian-based measure. The measure is normalization independent, i.e., is sensitive to dose patterns while not being biased by global dose scaling. The measure is free of tunable parameters and is bounded between zero and one. We also pro...

journal_title：Medical physics

authors： Paniak LD,Charland PM

更新日期：2008-11-01 00:00:00

abstract：:In this report we evaluate an image registration technique that can improve the information content of intraoperative image data by deformable matching of preoperative images. In this study, pretreatment 1.5 tesla (T) magnetic resonance (MR) images of the prostate are registered with 0.5 T intraoperative images. The m...

journal_title：Medical physics

authors： Bharatha A,Hirose M,Hata N,Warfield SK,Ferrant M,Zou KH,Suarez-Santana E,Ruiz-Alzola J,D'Amico A,Cormack RA,Kikinis R,Jolesz FA,Tempany CM

更新日期：2001-12-01 00:00:00

abstract：PURPOSE:Task Group 119 (TG-119) has been adopted for evaluating the adequacy of intensity-modulated radiation therapy (IMRT) commissioning and for establishing patient-specific IMRT quality assurance (QA) passing criteria in clinical practice. TG-119 establishes 95% confidence limits (CLs), which help clinics identify ...

journal_title：Medical physics

authors： Kearney V,Solberg T,Jensen S,Cheung J,Chuang C,Valdes G

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:Dosimetry with ionization chambers in clinical ion beams for radiation therapy requires correction for recombination effects. However, common radiation protocols discriminate between initial and general recombination and provide no universal correction method for the presence of both recombination types in ion ...

journal_title：Medical physics

authors： Christensen JB,Tölli H,Bassler N

更新日期：2016-10-01 00:00:00

abstract：PURPOSE:Prostate cancer ranks as one of the most common malignancies and currently represents the second leading cancer-specific cause of death in men. The current use of single modality transrectal ultrasound (TRUS) for biopsy guidance has a limited sensitivity and specificity for accurately identifying cancerous lesi...

journal_title：Medical physics

authors： Wan Y,Borsic A,Heaney J,Seigne J,Schned A,Baker M,Wason S,Hartov A,Halter R

更新日期：2013-06-01 00:00:00

abstract：PURPOSE:Dynamic 18 F-FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least-squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model p...

journal_title：Medical physics

authors： Ben Bouallègue F,Vauchot F,Mariano-Goulart D

更新日期：2019-03-01 00:00:00

abstract：PURPOSE:The paper presents a complete computer-aided detection (CAD) system for the detection of lung nodules in computed tomography images. A new mixed feature selection and classification methodology is applied for the first time on a difficult medical image analysis problem. METHODS:The CAD system was trained and t...

journal_title：Medical physics

authors： Tan M,Deklerck R,Jansen B,Bister M,Cornelis J

更新日期：2011-10-01 00:00:00

abstract：PURPOSE:To develop a new design of an x-ray beam shaper for helical computed tomography (CT) that increases the dose utilization. METHODS:For typical reconstruction algorithms in helical CT, different data are utilized with different weights during back-projection. In particular, data of the outer detector rows, i.e.,...

journal_title：Medical physics

authors： Köhler T,Brendel B,Proksa R

更新日期：2011-07-01 00:00:00

abstract：:Some limitations of conventional two-dimensional computer programs used to plan radiation therapy are presented. These include: a lack of involvement in defining the clinical problem; deficiencies in the algorithms for computing dose; failure to compute dose throughout the volume of interest; an inability to handle tr...

journal_title：Medical physics

authors： Goitein M

更新日期：1982-07-01 00:00:00

abstract：PURPOSE:The previously described 2D standardized vessel-wall-plus-plaque thickness (VWT) maps constructed from 3D ultrasound vessel wall measurements using an arc-length (AL) scaling approach adjusted the geometric variability of carotid arteries and has allowed for the comparisons of VWT distributions in longitudinal ...

journal_title：Medical physics

authors： Chen Y,Chiu B

更新日期：2016-12-01 00:00:00