Abstract：
PURPOSE:The aim of this study is to understand the characteristics of secondary electrons generated from the interaction of gold nanoparticles (GNPs) with x-rays as a function of nanoparticle size and beam energy and thereby further the understanding of GNP-enhanced radiotherapy. METHODS:The effective range, deflection angle, dose deposition, energy, and interaction processes of electrons produced from the interaction of x-rays with a GNP were calculated by Monte Carlo simulations. The GEANT4 code was used to simulate and track electrons generated from a 2, 50, and 100 nm diameter GNP when it is irradiated with a 50 kVp, 250 kVp, cobalt-60, and 6 MV photon beam in water. RESULTS:When a GNP was present, depending on the beam energies used, secondary electron production was increased by 10- to 2000-fold compared to an absence of a GNP. Low-energy photon beams were much more efficient at interacting with the GNP by two to three orders of magnitude compared to MV energies and increased the deflection angle. GNPs with larger diameters also contributed more dose. The majority of the energy deposition was outside the GNP, rather than self-absorbed by the nanoparticle. The mean effective range of electron tracks for the beams tested ranged from approximately 3 microm to 1 mm. CONCLUSIONS:These simulated results yield important insights concerning the spatial distributions and elevated dose in GNP-enhanced radiotherapy. The authors conclude that the irradiation of GNP at lower photon energies will be more efficient for cell killing. This conclusion is consistent with published studies.
journal_name
Med Physjournal_title
Medical physicsauthors
Leung MK,Chow JC,Chithrani BD,Lee MJ,Oms B,Jaffray DAdoi
10.1118/1.3539623subject
Has Abstractpub_date
2011-02-01 00:00:00pages
624-31issue
2eissn
0094-2405issn
2473-4209journal_volume
38pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:Empirical functions that describe primary beam profiles for radiotherapy treatment planning systems generally account for finite source size only on beams unmodified by blocks, wedges, or compensating filters. To incorporate the effects of extended sources on such modified beams and to treat the effect of an extended ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596222
更新日期：1988-09-01 00:00:00
abstract：PURPOSE:The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercia...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12469
更新日期：2017-10-01 00:00:00
abstract：PURPOSE:X-ray fluorescence computed tomography (XFCT) experiments have typically used pencil beams for data acquisition, which yielded good quality images of gold nanoparticles (AuNP) but prolonged the imaging time. Here we propose three novel collimator geometries for use with faster sheet beam XFCT data acquisition. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12893
更新日期：2018-06-01 00:00:00
abstract：:We are investigating computerized methods to ultimately characterize bone trabecular pattern from clinical skeletal radiographs. In this paper, we present a "phantom" for potential use in the development and evaluation of computerized methods for characterizing radiographic trabecular patterns and ultimately bone stre...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598743
更新日期：1999-11-01 00:00:00
abstract：:The EGS4 Monte Carlo code has been used to investigate the response of a PTW/diamond detector irradiated in both clinical and monoenergetic megavoltage electron beams ranging in energy from 5 to 20 MeV. The sensitive volume of the PTW/diamond detector simulated has a thickness of 0.4 mm and a diameter of 4.4 mm. Irrad...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598593
更新日期：1999-05-01 00:00:00
abstract：PURPOSE:To study the impact of target geometrical and linac operational parameters, such as target material and thickness, electron beam size, repetition rate, and mean current on the ability of the radiotherapy treatment head to deliver high-dose-rate x-ray irradiation in the context of novel linear accelerators capab...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12615
更新日期：2017-12-01 00:00:00
abstract：:A combination of Monte Carlo, convolution, and experimental techniques have been used to investigate bremsstrahlung production at 50 MeV in full-range targets to produce narrow elementary photon beams for scanning. Calculations using the ITS 3.0 Monte Carlo system for various target designs, including particle transpo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597681
更新日期：1996-04-01 00:00:00
abstract：PURPOSE:The authors investigate the extent to which Response Evaluation Criteria in Solid Tumors (RECIST) can predict tumor volumes in ideal geometric settings and using clinical data. METHODS:The authors consider a hierarchy of models including uniaxial ellipsoids, general ellipsoids, and composites of ellipsoids, us...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3577602
更新日期：2011-05-01 00:00:00
abstract：:Setting up and maintaining video display monitors properly will help to reduce display variation and improve overall presentation of the radiological image. Display monitor gray-scale characteristics were examined using the SMPTE test pattern. This test pattern may be used as a standard for adjusting brightness and co...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596846
更新日期：1992-05-01 00:00:00
abstract：PURPOSE:The primary feasibility steps of demonstrating the ability of microwave-induced thermoacoustic (TA) in phantoms have been previously reported. However, none were shown to target a diseased site in living subjects in thermoacoustic tomography (TAT) field so far. To determine the expressions of oncogenic surface ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3466696
更新日期：2010-08-01 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
pub_type： 杂志文章
doi：10.1118/1.597960
更新日期：1997-11-01 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：PURPOSE:Manual delineation of head and neck (H&N) organ-at-risk (OAR) structures for radiation therapy planning is time consuming and highly variable. Therefore, we developed a dynamic multiatlas selection-based approach for fast and reproducible segmentation. METHODS:Our approach dynamically selects and weights the a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13854
更新日期：2019-12-01 00:00:00
abstract：:The effects of small cavities on dose in water and the dose in a homogeneous nonunit density medium illustrate that inhomogeneities do not act independently in photon dose perturbation, and serve as two constraints which should be satisfied by approximate methods of computed tomography (CT) pixel-based dose calculatio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595294
更新日期：1983-03-01 00:00:00
abstract：:A theoretical analysis of the x-ray phase contrast imaging and its validation via synchrotron radiation imaging is here presented. Two different mathematical models have been followed: the simpler ray-optical approach and the more rigorous Fresnel-Kirchoff diffraction theory. Subsequently, the conditions upon which th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2126207
更新日期：2005-12-01 00:00:00
abstract：PURPOSE:Respiratory gating in PET is an approach used to minimize the negative effects of respiratory motion on spatial resolution. It is based on an initial determination of a patient's respiratory movements during a scan, typically using hardware based systems. In recent years, several fully automated databased algor...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3483784
更新日期：2010-10-01 00:00:00
abstract：:The use of characteristic-line radiation from rare-earth targets bombarded by high-energy (up to 1 MeV) electron beams has been evaluated as an x-ray source for dual energy K-edge subtraction imaging of the human coronary arteries. Two characteristic-line x-ray sources, one using the split K alpha 1 and K alpha 2 line...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596648
更新日期：1991-09-01 00:00:00
abstract：PURPOSE:Two types of tumor hypoxia most likely exist in human cancers: Chronic hypoxia due to the paucity of blood capillaries and acute hypoxia due to temporary shutdoWn of microvasculatures or fluctuation in the red cell flux. In a recent hypoxia imaging study using 18F-FMISO PET, the authors observed variation in tr...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3213092
更新日期：2009-10-01 00:00:00
abstract：PURPOSE:The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD). METHODS:Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and exp...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4813906
更新日期：2013-08-01 00:00:00
abstract：PURPOSE:In photon radiotherapy, respiratory-induced target motion can be accounted for by internal target volumes (ITV) or mid-ventilation target volumes (midV) defined on the basis of four-dimensional computed tomography (4D-CT). Intrinsic limitations of these approaches can result in target volumes that are not repre...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14023
更新日期：2020-04-01 00:00:00
abstract：:Digital tomosynthesis (DTS) is a fast, low-dose three-dimensional (3D) imaging approach which yields slice images with excellent in-plane resolution, though low plane-to-plane resolution. A stack of DTS slices can be reconstructed from a single limited-angle scan, with typical scan angles ranging from 10 degrees to 40...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2756941
更新日期：2007-08-01 00:00:00
abstract：PURPOSE:The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different...
journal_title：Medical physics
pub_type： 杂志文章,多中心研究
doi：10.1118/1.4901299
更新日期：2015-01-01 00:00:00
abstract：PURPOSE:Currently, in clinical practice of intensity-modulated proton therapy (IMPT), the influence of the minimum monitor unit (MU) constraint is taken into account through postprocessing after the optimization is completed. This may degrade the plan quality and plan robustness. This study aims to mitigate the impact ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12677
更新日期：2018-01-01 00:00:00
abstract：:Computed tomography dose index (CTDI) is a conventional indicator of the patient dose in CT studies. It is measured as the integration of the longitudinal single scan dose profile (SSDP) by using a 100-mm-long pencil ionization chamber and a single axial scan. However, the assumption that most of the SSDP is contained...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1835571
更新日期：2005-01-01 00:00:00
abstract：PURPOSE:This study (1) examines a variety of real-world cases where systematic errors were not detected by widely accepted methods for IMRT/VMAT dosimetric accuracy evaluation, and (2) drills-down to identify failure modes and their corresponding means for detection, diagnosis, and mitigation. The primary goal of detai...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4826166
更新日期：2013-11-01 00:00:00
abstract：:A scintillation dosemeter is calibrated for 90Sr/90Y beta rays from an ophthalmic applicator, using an extrapolation ionization chamber as a reference instrument. The calibration factor for the scintillation dosemeter agrees with that given by the manufacturer of the dosemeter within ca. 2%. The estimated overall unce...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1709490
更新日期：2004-05-01 00:00:00
abstract：:The purpose of this study was to implement the Monte Carlo method for clinical radiotherapy dose calculations. We used the EGS4/BEAM code to obtain the phase-space data for 6-20 MeV electron beams and 4, 6, and 15 MV photon beams for Varian Clinac 1800, 2100C, and 2300CD accelerators. A multiple-source model was used ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598729
更新日期：1999-10-01 00:00:00
abstract：:A 4-W, laser-based system for the positional readout of thermoluminescent (TL) plates was utilized to obtain dose profiles for a 60Co radiotherapy beam. Experimentally obtained glow curves for LiF resulting from the rapid heating rates characteristic of laser heating agreed well with results predicted using a first-or...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596580
更新日期：1990-05-01 00:00:00
abstract：PURPOSE:Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiotherapy by increasing photon energy and applying specialized beam-hard...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12927
更新日期：2018-07-01 00:00:00
abstract：PURPOSE:Multiple commercial, open-source, and academic software tools exist for objective quantification of lung density in computed tomography (CT) images. The purpose of this study was to evaluate the intersoftware reproducibility of CT lung density measurements. METHODS:Computed tomography images from 50 participan...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14130
更新日期：2020-07-01 00:00:00
