Abstract:
BACKGROUND AND PURPOSE:Differential baseline shifts between primary tumor and involved lymph nodes in locally advanced lung cancer patients compromise the accuracy of radiotherapy. The purpose of this study was to evaluate the performance of an average anatomy model (AAM) derived from repeat imaging and deformable registration to reduce these geometrical uncertainties. METHODS AND MATERIALS:An in-house implementation of a B-Spline deformable image registration (DIR) algorithm was first validated using three different validation approaches: (a) a circle method to test the consistency of the DIR, (b) fiducial marker target registration error, and (c) the recovery of a known deformation vector field (DVF). Subsequently, AAM was generated by first averaging five DVFs resulting from cone beam CT (CBCT) to planning CT (pCT) DIR and second by applying the inverse of the average DVF to the pCT. The proposed method was evaluated on 15 locally advanced lung cancer patients receiving daily motion compensated CBCT and a repeat CT (rCT) for adaptive radiotherapy. Reduction of systematic baseline shifts of the primary tumor were quantified for the fractions used to build the AAM as well as over the whole treatment and compared to the performance of the rCT. RESULTS:The deformable registration accuracy was ≤ 2 mm vector length for the first two validation methods and about 3 mm for the third method. The systematic baseline shifts over the five fractions prior to the rCT used to build the AAM reduced from 5.9 mm vector length relative to the pCT to 2.3 and 4.2 mm relative to the AAM and rCT, respectively. The overall systematic errors in the left-right, cranio-caudal, and anterior-posterior directions were [3.4, 3.8, 3.3] mm, [2.3, 2.9, 2.6] mm, and [2.3, 3.1, 2.7] mm for the pCT, AAM, and rCT, respectively. CONCLUSIONS:The AAM mitigates systematic errors occurring during treatment due to differential baseline shifts between the primary tumor and involved lymph nodes similar to (or even better than) rCT. The superior performance of the AAM in terms of the systematic error derived from the initial fractions indicates that further analysis of the optimum intervention time is required. This model has the potential to be used as an efficient and accurate alternative for rCT in adaptive radiotherapy of locally advanced lung cancer patients, obviating the need for rescanning and recontouring.
journal_name
Med Physjournal_title
Medical physicsauthors
Abdoli M,Van Kranen SR,Stankovic U,Rossi MMG,Belderbos JSA,Sonke JJdoi
10.1002/mp.12271subject
Has Abstractpub_date
2017-07-01 00:00:00pages
3570-3578issue
7eissn
0094-2405issn
2473-4209journal_volume
44pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::Analytic microdosimetry using Fourier transform techniques has been applied to internal alpha emitters. These techniques need revision and simplification for use with short-lived radionuclides such as those which may be useful for radioimmunotherapy. Analytic methods may have advantages over Monte Carlo methods in som...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596770
更新日期:1992-11-01 00:00:00
abstract:PURPOSE:In previous work, the authors developed and demonstrated the concept of an image reconstruction procedure aimed to unify gated and dynamic nuclear cardiac imaging, which the authors have termed five-dimensional (5D) SPECT. Gated imaging permits the clinician to evaluate wall motion and, through the use of stres...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3481507
更新日期:2010-09-01 00:00:00
abstract::The determination of the radiation exposure history of the population has become increasingly important in the study of the effects of low-level radiation. The present work was started to try to obtain an in vivo dosimeter that could give an indication of radiation exposure. Dental enamel is the only living tissue whi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595768
更新日期:1985-05-01 00:00:00
abstract::A slat collimator in single photon emission computed tomography consists of a set of parallel slats. As the collimator spins, the detector measures a one-dimensional projection data set. A complete data set can be obtained by rotating the detector/collimator assembly around the object (patient) while the collimator sp...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1485057
更新日期:2002-07-01 00:00:00
abstract:PURPOSE:Intensity-modulated proton therapy (IMPT) is known to be sensitive to patient setup and range uncertainty issues. Multiple robust optimization methods have been developed to mitigate the impact of these uncertainties. Here, we propose a new robust optimization method, which provides an alternative way of robust...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13276
更新日期:2019-01-01 00:00:00
abstract:BACKGROUND:Deep learning methods for radiomics/computer-aided diagnosis (CADx) are often prohibited by small datasets, long computation time, and the need for extensive image preprocessing. AIMS:We aim to develop a breast CADx methodology that addresses the aforementioned issues by exploiting the efficiency of pre-tra...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12453
更新日期:2017-10-01 00:00:00
abstract:PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12854
更新日期:2018-05-01 00:00:00
abstract::The Radiological Physics Center (RPC) developed two heterogeneous anthropomorphic quality assurance phantoms for use in verifying the accuracy of radiation delivery: one for intensity-modulated radiation therapy (IMRT) to the pelvis and the other for stereotactic body radiation therapy (SBRT) to the thorax. The purpos...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2737158
更新日期:2007-06-01 00:00:00
abstract::Anisotropy of dose distributions around 103Pd, 125I, and 192Ir sources for interstitial brachytherapy was examined. Dose rates around 125I models 6702 and 6711 and 192Ir sources were measured using lithium fluoride thermoluminescence dosimeters (LiF TLDs) in a water-equivalent, solid phantom. From these measured data ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597110
更新日期:1993-09-01 00:00:00
abstract::Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2996288
更新日期:2008-11-01 00:00:00
abstract::A simple modification is presented for two commercially available hyperthermia applicators which dramatically improves the regulation and dynamic control of the temperature at the bolus/tissue interface. This alteration requires the addition of a variable speed pump, bubble trap, simple heat exchanger, and a few minor...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597196
更新日期:1994-09-01 00:00:00
abstract::Tumor cells can be killed by heating to 42.5 degrees C. It is convenient to localize heating by passing electric current at 500 kHz through tissue between a pair of electrodes. It is desirable to determine, for a given electrode-tissue configuration, what the resulting field and, therefore, current distribution will b...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594235
更新日期:1976-07-01 00:00:00
abstract:PURPOSE:To compare how the inclusion of the uncertainties in dose and optical density affects the results of the calibration of Gafchromic(®) EBT3 radiochromic films. METHODS:Five methods of least square minimization were compared for calibration of radiochromic films. These differed in the way in which the uncertaint...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4811238
更新日期:2013-07-01 00:00:00
abstract::The photon response of silicon-diode neutron detectors is analyzed theoretically and measured in the 15-25-MeV region. The main mechanism for producing a response in the diode is shown to be the displacement of silicon atoms by scattering of electrons. If the photon source is an electron accelerator target, the respon...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594403
更新日期:1978-01-01 00:00:00
abstract:PURPOSE:One of the promising options for motion management in radiation therapy (RT) is the use of LINAC-compatible robotic-arm-mounted ultrasound imaging system due to its high soft tissue contrast, real-time capability, absence of ionizing radiation, and low cost. The purpose of this work is to develop a novel deep l...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13510
更新日期:2019-05-01 00:00:00
abstract::Treatment planning for brachytherapy requires the acquisition of geometrical information of the implant applicator and the patient anatomy. This is typically done using a simulator or a computed tomography scanner. In this study, we present a different method by which orthogonal images from a C-arm fluoroscopic machin...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1598851
更新日期:2003-09-01 00:00:00
abstract:PURPOSE:The authors are developing a system for calibrated breast density measurements using full field digital mammography (FFDM). Breast tissue equivalent (BTE) phantom images are used to establish baseline (BL) calibration curves at time zero. For a given FFDM unit, the full BL dataset is comprised of approximately ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4903299
更新日期:2015-02-01 00:00:00
abstract:PURPOSE:Accurate detection of pulmonary nodules remains a technical challenge in computer-aided diagnosis systems because some nodules may adhere to the blood vessels or the lung wall, which have low contrast compared to the surrounding tissues. In this paper, the analysis of typical shape features of candidate nodules...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4907961
更新日期:2015-03-01 00:00:00
abstract:PURPOSE:Currently applied calibration approaches lead to satisfying 3D roadmapping overlay and 3D reconstruction accuracies; however, the required calibration times are extensive. The aim of this paper is the introduction of a novel model-based approach for geometric system calibrations, leading to a significant reduct...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4931964
更新日期:2015-11-01 00:00:00
abstract::Luminance scatter fractions were measured for patients and phantoms in various regions of the chest film. Scatter fractions were found to be highly variable, being quite high in the regions of the chest with a large equivalent tissue thickness (e.g. mediastinum, chest wall, and subdiaphragmatic areas). For example, ap...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595027
更新日期:1981-09-01 00:00:00
abstract::In this article, we present a characterization of the effect of difference of Gaussians (DoG) filters in the detection of mammographic regions. DoG filters have been used previously in mammographic mass computer-aided detection (CAD) systems. As DoG filters are constructed from the subtraction of two bivariate Gaussia...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2358326
更新日期:2006-11-01 00:00:00
abstract::Various radionuclides have been proposed for systemic tumor therapy. However, in most dosimetric analysis of proposed radionuclides the charged particles are taken into consideration while the potential photons are ignored. The photons will cause undesirable irradiation of normal tissue, and increase the probability o...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2229428
更新日期:2006-09-01 00:00:00
abstract:PURPOSE:To develop a hypothesis-generating framework for automatic extraction of dose-outcome relationships from an in-house, analytic oncology database. METHODS:Dose-volume histograms (DVH) and clinical outcomes have been routinely stored to the authors' database for 684 head and neck cancer patients treated from 200...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4922686
更新日期:2015-07-01 00:00:00
abstract::In proton therapy, it is important to evaluate the field irradiated with protons and the deposited dose distribution in a patient's body. Positron emitters generated through fragmentation reactions of target nuclei can be used for this purpose. By detecting the annihilation gamma rays from the positron emitters, the a...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2712572
更新日期:2007-05-01 00:00:00
abstract:PURPOSE:The objective of this study is to develop a computational model for simulating 915 MHz microwave ablation (MWA), and verify the simulation predictions of transient temperature profiles against experimental measurements. Due to the limited experimental data characterizing temperature-dependent changes of tissue ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12359
更新日期:2017-09-01 00:00:00
abstract:PURPOSE:The purpose of this study was to investigate the impact of transverse magnetic fields on the dose response of a radiophotoluminescent glass dosimeter (RGD) in megavoltage photon beams. METHODS:The RGD relative response (i.e., RGD dose per absorbed dose to water at the midpoint of the detector in the absence of...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14054
更新日期:2020-04-01 00:00:00
abstract::Imaging of radiation dose distribution in gel phantoms by magnetic resonance techniques has previously been reported. In this paper a method of producing gels in which the distributions of radiation dose can also be visualized as a color change is reported. The color developed depends qualitatively and quantitatively ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596676
更新日期:1991-03-01 00:00:00
abstract:PURPOSE:The feasibility of intensity modulated brachytherapy (IMBT) to improve dose conformity for irregularly shaped targets has been previously investigated by researchers by means of using partially shielded sources. However, partial shielding does not fully explore the potential of IMBT. The goal of this study is t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3456598
更新日期:2010-07-01 00:00:00
abstract::System modeling is used to investigate the effect of various system parameters on the image quality in CCD-based x-ray imaging systems. The systems considered consist of a typical phosphor-based scintillating screen coupled to a CCD through lens or fiberoptic taper. Two applications, chest radiography and mammography,...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598072
更新日期:1997-02-01 00:00:00
abstract::A proton dose computational algorithm, performing an analytical superposition of infinitely narrow proton beamlets (ASPB) is introduced. The algorithm uses the standard pencil beam technique of laterally distributing the central axis broad beam doses according to the Moliere scattering theory extended to slablike vary...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2064887
更新日期:2005-12-01 00:00:00