Abstract:
PURPOSE:To evaluate the patient positioning accuracy and reproducibility of two commercially available immobilization systems for Stereotactic Body Radiotherapy (SBRT) treatment. METHODS:Forty one patients with lung (n=21) or liver (n=20) malignancies were assigned to one of the two immobilization devices: Elekta stereotactic body frame (SBF) with built-in stereotactic coordinate system and Civco modular indexing based frame (MIF) without stereotactic reference. All patients underwent the same simulation and planning procedure followed by cone beam CT (CBCT) guided treatment setup. A total of 151 CBCT images were analyzed. The systematic and random isocenter setup errors of the two systems were calculated and compared based on the daily setup corrections under CBCT guidance. RESULTS:There was not statistically significant difference between the two systems in terms of systematic setup errors in all three translational directions, for both lung and liver patients. The random errors for the lung patients under SBF setup were 1.8mm, 2.0mm and 2.9mm for the vertical, longitudinal and lateral directions, respectively compared to 3.6mm, 4.1mm, and 4.2mm for MIF. A similar trend was also observed for liver patients. The random errors of liver MIF setup reached 3.5mm, 6.1mm and 5.7mm for the vertical, longitudinal and lateral directions, respectively, with relatively smaller errors 1.7mm, 3.4mm and 2.6mm with SBF setup. Repeated CBCTs occurred for MIF system in 42.4% and 40.7% of the lung and liver treatment to verify couch corrections based on the institutional tolerance, resulting in prolonged setup time. Only 25% and 13.6% of the lung and liver treatment with SBF required with repeated CBCT. CONCLUSIONS:Without stereotactic coordinate reference, the body frame system tended to have larger random setup errors and patient positioning accuracy inevitably relies on the volumetric imaging guidance. Patient comfort and reproducibility should be clearly considered for selecting a system.
journal_name
Med Physjournal_title
Medical physicsauthors
Cao M,Cao N,Cardenes H,Fakiris A,Desrosiers C,Das Idoi
10.1118/1.4735009subject
Has Abstractpub_date
2012-06-01 00:00:00pages
3691-3692issue
6Part8eissn
0094-2405issn
2473-4209journal_volume
39pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:The authors previously introduced a methodology to generate a realistic three-dimensional (3D), high-resolution, computer-simulated breast phantom based on empirical data. One of the key components of such a phantom is that it provides a means to produce a realistic simulation of clinical breast compression. In...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3637500
更新日期:2011-10-01 00:00:00
abstract:PURPOSE:Current respiratory motion monitoring devices used for motion synchronization in medical imaging and radiotherapy provide either 1D respiratory signal over a specific region or 3D information based on few external or internal markers. On the other hand, newer technology may offer the potential to monitor the en...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3589131
更新日期:2011-06-01 00:00:00
abstract::A photon transport algorithm for fully three-dimensional radiotherapy treatment planning has been developed based on the discrete ordinates (SN) solution of the Boltzmann equation. The algorithm is characterized by orthogonal adaptive meshes, which place additional points where large gradients occur and a procedure to...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2960247
更新日期:2008-09-01 00:00:00
abstract:PURPOSE:Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12796
更新日期:2018-04-01 00:00:00
abstract:PURPOSE:The automated correct segmentation of left and right lungs is a nontrivial problem, because the tissue layer between both lungs can be quite thin. In the case of lung segmentation with left and right lung models, overlapping segmentations can occur. In this paper, the authors address this issue and propose a so...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4894817
更新日期:2014-10-01 00:00:00
abstract::A double-mirror multilayer monochromator was developed for the purpose of irradiating live cell cultures at the Synchrotron Radiation Center, University of Wisconsin-Madison. The monochromator is designed for the soft x-ray region with photon energies between 270 and 2400 eV. Multilayer mirrors with 55 bilayers of W/C...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598259
更新日期:1998-05-01 00:00:00
abstract:PURPOSE:To develop a real-time markerless 3D tumor tracking using kilovoltage (kV) cone-beam CT (CBCT) projection images during volumetric modulated arc therapy (VMAT) treatment of lung tumors. METHODS:The authors have developed a method to identify the position of lung tumors during VMAT treatment, where the current ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4821545
更新日期:2013-10-01 00:00:00
abstract:PURPOSE:The aim of this work is to search for new metrics that could give more reliable acceptance/rejection criteria on the IMRT verification process and to offer solutions to the discrepancies found among different conventional metrics. Therefore, besides conventional metrics, new ones are proposed and evaluated with...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4964796
更新日期:2016-11-01 00:00:00
abstract::With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this st...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1897464
更新日期:2005-05-01 00:00:00
abstract::This paper examines statistical errors in the measurement of arterial stenoses by digital videodensitometry. Images of vessel phantoms were acquired using digital subtraction angiographic techniques with low concentrations of an iodine contrast medium and low levels of x-ray exposure. Effects of the spatial and tempor...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595652
更新日期:1985-11-01 00:00:00
abstract::Calibrated C-arm fluoroscopy is used for a variety of surgical procedures where surgical tools and anatomical structures need to be located in space. Calibration can be performed online by combining measurements of the geometry of the image (center and radius) with measurements of a grid of fiducial markers. This arti...
journal_title:Medical physics
pub_type: 杂志文章,多中心研究
doi:10.1118/1.1781331
更新日期:2004-09-01 00:00:00
abstract::In this paper, two new boundary tracing algorithms for segmentation of breast masses are presented. These new algorithms are based on the dynamic programming-based boundary tracing (DPBT) algorithm proposed in Timp and Karssemeijer, [S. Timp and N. Karssemeijer, Med. Phys. 31, 958-971 (2004)] The DPBT algorithm contai...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2791034
更新日期:2007-11-01 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::Two recently developed A 150 plastic-equivalent gas mixtures have been tested for suitability in proportional counter applications. Methane- and propane-based "tissue-equivalent" gases were also included for comparison purposes. Event-size weighted dose distributions were measured in a 14.8-MeV neutron beam. Resolutio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595536
更新日期:1984-07-01 00:00:00
abstract:PURPOSE:To improve the performance of a computer-aided detection (CAD) system for mass detection by using four-view information in screening mammography. METHODS:The authors developed a four-view CAD system that emulates radiologists' reading by using the craniocaudal and mediolateral oblique views of the ipsilateral ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3560462
更新日期:2011-04-01 00:00:00
abstract::A small, lightweight, single-focusing magnetic spectrometer was designed, assembled, and tested for analysis of electron beams from radiotherapy electron linacs. The objective was to develop a low cost, simple device that could be easily replicated in other medical centers, and to demonstrate the practicality of indiv...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597271
更新日期:1994-11-01 00:00:00
abstract::The purpose of this study is to incorporate the dosimetric effect of random patient positioning uncertainties directly into a commercial treatment planning system's IMRT plan optimization algorithm through probabilistic treatment planning (PTP) and compare coverage of this method with margin-based planning. In this wo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3176940
更新日期:2009-09-01 00:00:00
abstract::The observation of scattered radiations of larger wavelength than the primary had been repeatedly rejected or explained away by many researchers, including Compton. After years of vacillations, he recognized the effect named after him and was the first to develop a quantal equation predicting the wavelength of scatter...
journal_title:Medical physics
pub_type: 传,历史文章,杂志文章
doi:10.1118/1.595046
更新日期:1981-11-01 00:00:00
abstract:PURPOSE:To investigate how using different sets of decision criteria impacts the quality of intensity modulated radiation therapy (IMRT) plans obtained by multiobjective optimization. METHODS:A multiobjective optimization evolutionary algorithm (MOEA) was used to produce sets of IMRT plans. The MOEA consisted of two i...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3589128
更新日期:2011-06-01 00:00:00
abstract:PURPOSE:Currently, only iodine- and barium-based contrast media (CM) are used in clinical contrast-enhanced computed tomography (CE-CT). High-Z metals would produce a higher contrast at equal mass density for the x-ray spectra used in clinical CT. Using such materials might allow for significant dose reductions in CE-C...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3658738
更新日期:2011-12-01 00:00:00
abstract:PURPOSE:Imaging the knee under realistic load-bearing conditions can be carried out in a horizontal plane using a C-arm CT scanner. Human subjects can be scanned in a standing position and acquired data successfully reconstructed. However, reconstructing this data is a challenge due to significant artifacts that are in...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4736213
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Precise segmentation of clinical target volume (CTV) is the key to stomach cancer radiotherapy. We proposed a novel stochastic width - deep neural network (SW-DNN) for better automatically contouring stomach CTV METHODS: SW-DNN was an end-to-end approach, of which the core component was a novel SW mechanism tha...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14733
更新日期:2021-01-27 00:00:00
abstract:PURPOSE:Adequate evaluation of the results from multi-institutional trials involving light ion beam treatments requires consideration of the planning margins applied to both targets and organs at risk. A major uncertainty that affects the size of these margins is the conversion of x ray computed tomography numbers (XCT...
journal_title:Medical physics
pub_type: 杂志文章,多中心研究
doi:10.1118/1.4870956
更新日期:2014-06-01 00:00:00
abstract::A new calibration algorithm (GLAaS) to derive absolute dose maps from images acquired with the Varian PV-aS500 electronic portal imager (based on amorphous silicon detectors) has been developed incorporating the dependence of detector response on primary and transmitted radiation and on field size. Detector calibratio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2218314
更新日期:2006-08-01 00:00:00
abstract:PURPOSE:Most radiation therapy optimization problems can be formulated as an unconstrained problem and solved efficiently by quasi-Newton methods such as the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) algorithm. However, several next generation planning techniques such as total variation regularization- b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12165
更新日期:2017-04-01 00:00:00
abstract:PURPOSE:Radiochromic film provides dose measurement at high spatial resolution, but often is not preferred for routine evaluation of patient-specific intensity modulated radiation therapy (IMRT) plans owing to ease-of-use factors. The authors have established an efficient protocol that combines calibration and measurem...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4754797
更新日期:2012-10-01 00:00:00
abstract::An adaptive linear element (Adaline) was developed to estimate the two-dimensional scatter exposure distribution in digital portable chest radiographs (DPCXR). DPCXRs and quantitative scatter exposure measurements at 64 locations throughout the chest were acquired for ten radiographically normal patients. The Adaline ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596978
更新日期:1993-07-01 00:00:00
abstract:PURPOSE:Electronic portal imagers (EPIDs) with high detective quantum efficiencies (DQEs) are sought to facilitate the use of the megavoltage (MV) radiotherapy treatment beam for image guidance. Potential advantages include high quality (treatment) beam's eye view imaging, and improved cone-beam computed tomography (CB...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4927786
更新日期:2015-09-01 00:00:00
abstract:PURPOSE:As radiation therapy evolves toward more adaptive techniques, image guidance plays an increasingly important role, not only in patient setup but also in monitoring the delivered dose and adapting the treatment to patient changes. This study aimed to validate a method for evaluation of delivered intensity modula...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4903292
更新日期:2015-01-01 00:00:00
abstract::An improved reconstructed stereoscopic x-ray image display system, based on the principle of binocular parallax, is described. Pulse-synchronized operation of two triode x-ray tubes and one plumbicon TV camera is employed to separate the left and right images for presentation to the two eyes, respectively. The princip...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595365
更新日期:1983-09-01 00:00:00