Abstract:
PURPOSE:To present a system for robotic 4D ultrasound (US) imaging concurrent with radiotherapy beam delivery and estimate the proportion of liver stereotactic ablative body radiotherapy (SABR) cases in which robotic US image guidance can be deployed without interfering with clinically used VMAT beam configurations. METHODS:The image guidance hardware comprises a 4D US machine, an optical tracking system for measuring US probe pose, and a custom-designed robot for acquiring hands-free US volumes. In software, a simulation environment incorporating the LINAC, couch, planning CT, and robotic US guidance hardware was developed. Placement of the robotic US hardware was guided by a target visibility map rendered on the CT surface by using the planning CT to simulate US propagation. The visibility map was validated in a prostate phantom and evaluated in patients by capturing live US from imaging positions suggested by the visibility map. In 20 liver SABR patients treated with VMAT, the simulation environment was used to virtually place the robotic hardware and US probe. Imaging targets were either planning target volumes (PTVs, range 5.9-679.5 ml) or gross tumor volumes (GTVs, range 0.9-343.4 ml). Presence or absence of mechanical interference with LINAC, couch, and patient body as well as interferences with treated beams was recorded. RESULTS:For PTV targets, robotic US guidance without mechanical interference was possible in 80% of the cases and guidance without beam interference was possible in 60% of the cases. For the smaller GTV targets, these proportions were 95% and 85%, respectively. GTV size (1/20), elongated shape (1/20), and depth (1/20) were the main factors limiting the availability of noninterfering imaging positions. The robotic US imaging system was deployed in two liver SABR patients during CT simulation with successful acquisition of 4D US sequences in different imaging positions. CONCLUSIONS:This study indicates that for VMAT liver SABR, robotic US imaging of a relevant internal target may be possible in 85% of the cases while using treatment plans currently deployed in the clinic. With beam replanning to account for the presence of robotic US guidance, intrafractional US may be an option for 95% of the liver SABR cases.
journal_name
Med Physjournal_title
Medical physicsauthors
Schlosser J,Gong RH,Bruder R,Schweikard A,Jang S,Henrie J,Kamaya A,Koong A,Chang DT,Hristov Ddoi
10.1118/1.4964454subject
Has Abstractpub_date
2016-11-01 00:00:00pages
5951issue
11eissn
0094-2405issn
2473-4209journal_volume
43pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::Lag and residual contrast have been quantified in an amorphous selenium (a-Se) active-matrix flat-panel imager (AMFPI) as a function of frame time, kilovoltage (kV) and megavoltage (MV) x-ray photon energies and amount of radiation incident on the detector. The AMFPI contains a 200 microm thick a-Se layer deposited on...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1713298
更新日期:2004-05-01 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:PURPOSE:An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. METHODS:Optimized ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12914
更新日期:2018-06-01 00:00:00
abstract:PURPOSE:It is estimated that 7% of women in the western world will develop palpable breast cysts in their lifetime. Even though cysts have been correlated with risk of developing breast cancer, many of them are benign and do not require follow-up. We develop a method to discriminate benign solitary cysts from malignant...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12110
更新日期:2017-03-01 00:00:00
abstract:PURPOSE:To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. METHODS:In dual-energy CT, besides the material-specific information, one may also synthesi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3658568
更新日期:2011-12-01 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::Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2000647
更新日期:2005-09-01 00:00:00
abstract:PURPOSE:To improve the dose homogeneity in patch-field proton therapy using beam current modulation. METHODS:MCNPX simulations were performed for various configurations of the Mevion S250 beamline. Spread-out Bragg peak (SOBP) dose distributions were calculated, and lateral and distal dose profiles were extracted for ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735806
更新日期:2012-06-01 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::With the increasing complexity of dose patterns external beam radiotherapy, there is a great need for new types of dosimeters. We studied the first prototype of a new dosimeter array consisting of water-equivalent plastic scintillating fibers for dose measurement in external beam radiotherapy. We found that this array...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2719363
更新日期:2007-05-01 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::Small photon fields are increasingly used in modern radiotherapy and especially in IMRT and SRS/SRT treatments. The uncertainties related to small field profile measurements can introduce significant systematic errors to the overall treatment process. These measurements are challenging mainly due to the absence of cha...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2977829
更新日期:2008-10-01 00:00:00
abstract::For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2168067
更新日期:2006-03-01 00:00:00
abstract::Transmission imaging is receiving increasing attention in SPECT due to the need to compensate for nonuniform attenuation in cardiac-chest SPECT. The quality of a transmission image has an important effect on the measured attenuation distribution. To improve image quality, knowledge of the performance characteristics o...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596752
更新日期:1992-09-01 00:00:00
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 regi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12271
更新日期:2017-07-01 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:PURPOSE:To measure the calibration curves of EBT3 dosimetry films in photon and proton beams and to quantify the related uncertainties from one beam type to another. METHODS:EBT3 Gafchromic films have similar properties than EBT2 with a symmetric construction and a matte polyester substrate to prevent Newton's ring ar...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735176
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Patient-specific QA of highly conformal radiotherapy treatments are usually conducted using 2D or 3D dosimetry of the incident dose distribution in a water-equivalent phantom. However, dosimeters typically used for this task usually lack in either spatial resolution or dose accuracy. The purpose of this work is...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4736526
更新日期:2012-08-01 00:00:00
abstract:PURPOSE:Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is correc...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4831757
更新日期:2013-12-01 00:00:00
abstract:PURPOSE:To use EGSnrc Monte Carlo simulations for magnetic field dosimetry to determine optimal measurement orientations, calculate beam quality conversion factors for 32 cylindrical and three parallel-plate (PP) ion chambers, evaluate the beam quality and angular dependence of these factors, and examine the magnetic f...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12716
更新日期:2018-02-01 00:00:00
abstract:PURPOSE:To quantify the inter fraction variation of spatial location of high dose regions of OARs in MR-image based cervix brachytherapy using rigid registration algorithm. METHODS:Retrospective analysis of 27 previously treated patients under EMBRACE multi-centric trial was evaluated. Each patient had two application...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735513
更新日期:2012-06-01 00:00:00
abstract::A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essen...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598839
更新日期:2000-02-01 00:00:00
abstract:PURPOSE:In this work, the fabrication, operation, and evaluation of a probe-format graphite calorimeter - herein referred to as Aerrow - as an absolute clinical dosimeter of high-energy photon beams while in the presence of a B = 1.5 T magnetic field is described. Comparable to a cylindrical ionization chamber (IC) in ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13968
更新日期:2020-03-01 00:00:00
abstract:PURPOSE:To study and compare the dose response curves of the new GafChromic EBT3 film for megavoltage and kilovoltage x-ray beams, with different spatial resolution. METHODS:Two sets of EBT3 films (lot#A101711-02) were exposed to each x-ray beam (6MV, 15MV and 50kV) at 8 dose values (50-3200cGy). The megavoltage beams...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735153
更新日期:2012-06-01 00:00:00
abstract::The purpose of this work is to calculate the dose perturbations due to the presence of iodine contrast media in catheter-based intravascular brachytherapy (IVBT). The EGSnrc Monte Carlo system was used to perform the calculation for the two most commonly used beta and gamma sources (90Sr and 192Ir as well as for a var...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1367279
更新日期:2001-05-01 00:00:00
abstract:PURPOSE:In 3D gradient echo magnetic resonance imaging (MRI), strong field gradients B0macro are visually observed at air/tissue interfaces. At low spatial resolution in particular, the respective field gradients lead to an apparent increase in intravoxel dephasing, and subsequently, to signal loss or inaccurate R2* es...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12318
更新日期:2017-07-01 00:00:00
abstract:PURPOSE:Real-time adaptive planning and treatment has been infeasible due in part to its high computational complexity. There have been many recent efforts to utilize graphics processing units (GPUs) to accelerate the computational performance and dose accuracy in radiation therapy. Data structure and memory access pat...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4895822
更新日期:2014-10-01 00:00:00
abstract::For radiation dosimetry calculations of radiolabeled monoclonal antibodies, (MAB), pharmacokinetics are critical. Specifically, pharmacokinetic modeling is a useful component of estimation of cumulated activity in various source organs in the body. It is thus important to formulate general methods of pharmacokinetic m...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.597047
更新日期:1993-03-01 00:00:00
abstract:PURPOSE:Deformable registration generally relies on the assumption that the sought spatial transformation is smooth. Yet, breathing motion involves sliding of the lung with respect to the chest wall, causing a discontinuity in the motion field, and the smoothness assumption can lead to poor matching accuracy. In respon...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3679009
更新日期:2012-02-01 00:00:00
abstract:PURPOSE:Due to the low contrast, blurry boundaries, and large amount of shadows in breast ultrasound (BUS) images, automatic tumor segmentation remains a challenging task. Deep learning provides a solution to this problem, since it can effectively extract representative features from lesions and the background in BUS i...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13268
更新日期:2019-01-01 00:00:00