Abstract：
:Available deformable registration methods are often inaccurate over large organ variation encountered, for example, in the rectum and bladder. The authors developed a novel approach to accurately and effectively register large deformations in the prostate region for adaptive radiation therapy. A software tool combining a fast symmetric demons algorithm and the use of masks was developed in C++ based on ITK libraries to register CT images acquired at planning and before treatment fractions. The deformation field determined was subsequently used to deform the delivered dose to match the anatomy of the planning CT. The large deformations involved required that the bladder and rectum volume be masked with uniform intensities of -1000 and 1000 HU, respectively, in both the planning and treatment CTs. The tool was tested for five prostate IGRT patients. The average rectum planning to treatment contour overlap improved from 67% to 93%, the lowest initial overlap is 43%. The average bladder overlap improved from 83% to 98%, with a lowest initial overlap of 60%. Registration regions were set to include a volume receiving 4% of the maximum dose. The average region was 320 x 210 x 63, taking approximately 9 min to register on a dual 2.8 GHz Linux system. The prostate and seminal vesicles were correctly placed even though they are not masked. The accumulated doses for multiple fractions with large deformation were computed and verified. The tool developed can effectively supply the previously delivered dose for adaptive planning to correct for interfractional changes.
journal_name
Med Physjournal_title
Medical physicsauthors
Godley A,Ahunbay E,Peng C,Li XAdoi
10.1118/1.3095777subject
Has Abstractpub_date
2009-04-01 00:00:00pages
1433-41issue
4eissn
0094-2405issn
2473-4209journal_volume
36pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:Couch-mounted cone-beam computed tomography (CBCT) imaging devices with independently rotatable x-ray source and flat-panel detector arms for acquisitions of arbitrary regions of interest (ROI) have recently been introduced in image-guided radiotherapy (IGRT). This work analyzes mechanical limitations and gravi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12033
更新日期：2017-01-01 00:00:00
abstract：:Compared with slice-by-slice approaches for SPECT reconstruction, three-dimensional iterative methods provide a more accurate physical model and an improved SPECT image. Clinical application of these methods, however, is limited primarily to their computational demands. This paper investigates the methods for approxim...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598030
更新日期：1997-09-01 00:00:00
abstract：PURPOSE:Anatomical variations occur during head and neck (H&N) radiotherapy treatment. kV cone-beam computed tomography (CBCT) images can be used for daily dose monitoring to assess dose variations owing to anatomic changes. Deep learning methods (DLMs) have recently been proposed to generate pseudo-CT (pCT) from CBCT ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14387
更新日期：2020-10-01 00:00:00
abstract：PURPOSE:Sterile radiation reduction gloves have been widely used in the past decade to provide modest decreases in operator hand dose when the hands are placed in the field of view (FOV). While multiple publications have quantified the potential dose reduction from the use of such gloves, possible effects on the patien...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734747
更新日期：2012-06-01 00:00:00
abstract：:The anti-scatter grid has been widely used to reject scatter and increase the perceptibility of a low-contrast object in chest radiography; however, it also attenuated the primary x-rays, resulting in a substantial loss of information and an increased relative noise level in heavily attenuated regions. A more dose eff...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2739805
更新日期：2007-07-01 00:00:00
abstract：PURPOSE:To assess and compare the dosimetric impact of dynamic multileaf collimator (DMLC) tracking and gating as motion correction strategies to account for intrafraction motion during conventionally fractionated prostate radiotherapy. METHODS:A dose reconstruction method was used to retrospectively assess the dose d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892605
更新日期：2014-09-01 00:00:00
abstract：:An in vitro radiographic technique which uses saline/iodine displacement has been developed to study the thickness of bone-equivalent and soft-tissue-equivalent materials within atherosclerotic plaques in arterial specimens which have been cut open longitudinally and laid flat. Results concerning the optimization of t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597916
更新日期：1997-01-01 00:00:00
abstract：PURPOSE:The aim of this study was to implement a Dirichlet process mixture (DPM) model for automatic tumor edge identification on (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) images by optimizing the parameters on which the algorithm depends, to validate it experimentally, and to test its robus...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4947123
更新日期：2016-05-01 00:00:00
abstract：PURPOSE:This work is to evaluate the effects of Compton current generation in three small-volume ionization chambers on measured beam characteristics for electron fields. METHODS:Beam scans were performed using Exradin A16, A26, and PTW 31014 microchambers. Scans with varying chamber components shielded were performed...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4929555
更新日期：2015-10-01 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：:The dosimetry for radiocolloid therapy of cystic craniopharyngiomas is investigated. Analytical calculations based on the Loevinger and the Berger formulas for electrons and photons, respectively, are compared with Monte Carlo simulations. The role of the material of which the colloid introduced inside the craniophary...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1599653
更新日期：2003-09-01 00:00:00
abstract：PURPOSE:This paper presents the design of a micro-CT guided small animal robotic needle positioning system. In order to simplify the robotic design and maintain a small targeting error, a novel implementation of the remote center of motion is used in the system. The system has been developed with the objective of achie...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4771958
更新日期：2013-01-01 00:00:00
abstract：PURPOSE:To develop a fluoroscopy imaging based approach that can determine the magnitude and phase variation in respiratory motion against the treatment planning images in order to quantify the online patient setup deviation in thoracic cancer IGRT for the real time adaptive patient positionadjustment. METHODS:A numer...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734876
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:The authors investigate performance of thin-film cadmium telluride (CdTe) in detecting high-energy (6 MV) x rays. The utilization of this material has become technologically feasible only in recent years due to significant development in large area photovoltaic applications. METHODS:The CdTe film is combined w...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3438082
更新日期：2010-08-01 00:00:00
abstract：:The wall of an ionization chamber is commonly assumed to have a negligible effect on chamber response in electron beams. For cylindrical chambers with thin walls this assumption is valid. However, parallel-plate chambers commonly possess large mechanical supports which may affect chamber response in a manner not accou...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596165
更新日期：1988-01-01 00:00:00
abstract：:An algorithmic solution to the biological effective dose (BED) calculation from the Lea-Catcheside formula for a piecewise defined function is presented. Data from patients treated for metastatic thyroid cancer were used to illustrate the solution. The Lea-Catcheside formula for the G-factor of the BED is integrated n...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3070587
更新日期：2009-03-01 00:00:00
abstract：:Intensity modulated radiotherapy (IMRT) requires extensive knowledge of multileaf collimator (MLC) leaf positioning accuracy, precision, and long-term reproducibility. We have developed a technique to efficiently measure the absolute position of each MLC leaf, over the range of leaf positions utilized in IMRT, based o...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1564091
更新日期：2003-05-01 00:00:00
abstract：PURPOSE:Tissue textures have been recognized as biomarkers for various clinical tasks. In computed tomography (CT) image reconstruction, it is important but challenging to preserve the texture when lowering x-ray exposure from full- toward low-/ultra-low dose level. Therefore, this paper aims to explore the texture-dos...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14449
更新日期：2020-10-01 00:00:00
abstract：PURPOSE:Monte Carlo (MC) dose calculation is generally superior to analytical dose calculation (ADC) used in commercial TPS to model the dose distribution especially for heterogeneous sites, such as lung and head/neck patients. The purpose of this study was to provide a validated, fast, and open-source MC code, MCsquar...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13231
更新日期：2018-12-01 00:00:00
abstract：:Scanning film densitometry routinely used for obtaining dosimetric information about therapy treatment beams is subject to several sources of inaccuracies. The most significant of these are described and appropriate methods of testing are presented. This establishes the need for adequate acceptance testing followed by...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595407
更新日期：1983-09-01 00:00:00
abstract：PURPOSE:Magnetic particle imaging (MPI) is a relatively new method to image the spatial distribution of magnetic nanoparticle (MNP) tracers administered to the body with high spatial and temporal resolution using an inhomogeneous magnetic field. The spatial information of the MNP's is encoded using a field free point (...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13411
更新日期：2019-04-01 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
abstract：PURPOSE:To evaluate the accuracy of skin dose determination for composite multibeam 3D conformal radiation therapy (3DCRT) and intensity modulated radiation therapy (IMRT) treatments using optically stimulated luminescent dosimeters (OSLDs) and Eclipse treatment planning system. METHODS:Surface doses measured by OSLDs...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4890795
更新日期：2014-08-01 00:00:00
abstract：PURPOSE:To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we des...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13872
更新日期：2019-12-01 00:00:00
abstract：:The intensity modulated arc has been proposed as an alternative to tomotherapy. Treatment planing systems more typically model the conventional step and shoot or sliding window dynamic multileaf collimator (DMLC) deliveries, and may not support intensity modulated arc therapy (IMAT). As well, another potential drawbac...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1508110
更新日期：2002-10-01 00:00:00
abstract：:In x-ray spectral measurement using a semiconductor detector system, accurate positioning of the detector in front of the anode is very important. This needs accurate determination of the focal spot position on the target in an x-ray tube. We present a simple technique to determine the focal spot position accurately. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597122
更新日期：1993-07-01 00:00:00
abstract：PURPOSE:To develop a novel three-dimensional (3D) hybrid-encoding framework using compressed sensing (CS) and Toeplitz encoding with variable phase-scrambled radio-frequency (RF) excitation, which has the following advantages: low power deposition of RF pulses, reduction of the signal dynamic range, no additional hardw...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13987
更新日期：2020-04-01 00:00:00
abstract：PURPOSE:This work investigates the energy response and dose-response curve determinations for XR-QA2 radiochromic film dosimetry system used for synchrotron radiation work and for quality assurance in diagnostic radiology, in the range of effective energies 18-46.5 keV. METHODS:Pieces of XR-QA2 films were irradiated, ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4939063
更新日期：2016-01-01 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：:Carlo Fidani Peel Regional Cancer Center at the Credit Valley Site of the Credit Valley Hospital and Trillium Health Center is currently undergoing a redevelopment to build a brachytherapy suite and associated areas with a projected start date of April 2013. The new brachytherapy suite will be located in the PRCC, and...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4740117
更新日期：2012-07-01 00:00:00
