Abstract:
PURPOSE:The authors describe the integration of optical imaging with a targeted small animal irradiator device, focusing on design, instrumentation, 2D to 3D image registration, 2D targeting, and the accuracy of recovering and mapping the optical signal to a 3D surface generated from the cone-beam computed tomography (CBCT) imaging. The integration of optical imaging will improve targeting of the radiation treatment and offer longitudinal tracking of tumor response of small animal models treated using the system. METHODS:The existing image-guided small animal irradiator consists of a variable kilovolt (peak) x-ray tube mounted opposite an aSi flat panel detector, both mounted on a c-arm gantry. The tube is used for both CBCT imaging and targeted irradiation. The optical component employs a CCD camera perpendicular to the x-ray treatment/imaging axis with a computer controlled filter for spectral decomposition. Multiple optical images can be acquired at any angle as the gantry rotates. The optical to CBCT registration, which uses a standard pinhole camera model, was modeled and tested using phantoms with markers visible in both optical and CBCT images. Optically guided 2D targeting in the anterior/posterior direction was tested on an anthropomorphic mouse phantom with embedded light sources. The accuracy of the mapping of optical signal to the CBCT surface was tested using the same mouse phantom. A surface mesh of the phantom was generated based on the CBCT image and optical intensities projected onto the surface. The measured surface intensity was compared to calculated surface for a point source at the actual source position. The point-source position was also optimized to provide the closest match between measured and calculated intensities, and the distance between the optimized and actual source positions was then calculated. This process was repeated for multiple wavelengths and sources. RESULTS:The optical to CBCT registration error was 0.8 mm. Two-dimensional targeting of a light source in the mouse phantom based on optical imaging along the anterior/posterior direction was accurate to 0.55 mm. The mean square residual error in the normalized measured projected surface intensities versus the calculated normalized intensities ranged between 0.0016 and 0.006. Optimizing the position reduced this error from 0.00016 to 0.0004 with distances ranging between 0.7 and 1 mm between the actual and calculated position source positions. CONCLUSIONS:The integration of optical imaging on an existing small animal irradiation platform has been accomplished. A targeting accuracy of 1 mm can be achieved in rigid, homogeneous phantoms. The combination of optical imaging with a CBCT image-guided small animal irradiator offers the potential to deliver functionally targeted dose distributions, as well as monitor spatial and temporal functional changes that occur with radiation therapy.
journal_name
Med Physjournal_title
Medical physicsauthors
Weersink RA,Ansell S,Wang A,Wilson G,Shah D,Lindsay PE,Jaffray DAdoi
10.1118/1.4894730subject
Has Abstractpub_date
2014-10-01 00:00:00pages
102701issue
10eissn
0094-2405issn
2473-4209journal_volume
41pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:Upgrade and benchmarking of a research 4D treatment planning system (4DTPS) suitable for realistic patient treatment planning and treatment simulations taking into account specific requirements for scanned ion beam therapy, i.e., modeling of dose heterogeneities due to interplay effects and range changes caused...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4800802
更新日期:2013-05-01 00:00:00
abstract::Positron emission tomography (PET) has shown an increase in both sensitivity and specificity over computed tomography (CT) in lung cancer. However, motion artifacts in the 18F fluorodioxydoglucose (FDG) PET images caused by respiration persists to be an important factor in degrading PET image quality and quantificatio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1448824
更新日期:2002-03-01 00:00:00
abstract:PURPOSE:This article presents a new reconstruction method for 3D imaging using a multiple 360 degrees circular orbit cone beam CT system, specifically a way to combine 3D volumes reconstructed with each orbit. The main goal is to improve the noise performance in the combined image while avoiding cone beam artifacts. M...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3484058
更新日期:2010-10-01 00:00:00
abstract:PURPOSE:To determine the accuracy of VMAT treatment planning and delivery for patients undergoing radiotherapy in the head and neck. METHOD AND MATERIALS:A dosimetric study of a typical head and neck treatment plan has been carried out using Chamber, film and TLD's placed inside an anthropomorphic phantom. Lateral and...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735478
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Lung cancer is a major cause of cancer deaths, and the 5-year survival rate of stage IV lung cancer patients is only 2%. However, the 5-year survival rate of stage I lung cancer patients significantly increases to 50%. As such, spiral computed tomography (CT) scans are necessary to diagnose high-risk lung cance...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12331
更新日期:2017-08-01 00:00:00
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::A method for finding optimal primary fluence profiles for multiple field external beam radiation therapy techniques has been developed using a radiobiologically based objective function that quantifies the probability of achieving complication-free tumor control, P+. The objective function P+ has the valuable property...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596971
更新日期:1993-07-01 00:00:00
abstract::The purpose of this study was to quantify in-stent restenoses with 3D B mode and power Doppler ultrasound (U.S.) imaging. In-stent restenoses were mimicked with vascular phantoms in which a nonferromagnetic prototype stent (Boston Scientific) and a ferromagnetic clinical stainless steel stent (Palmaz P295) were embedd...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3062944
更新日期:2009-02-01 00:00:00
abstract::The purpose of the present study is to characterize electron contamination in photon beams in different clinical situations. Variations with field size, beam modifier (tray, shaping block) and source-surface distance (SSD) were studied. Percentage depth dose measurements with and without a purging magnet and replacing...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1895793
更新日期:2005-05-01 00:00:00
abstract:PURPOSE:Melanoma is the most lethal of the three primary skin cancers, including also basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), which are less lethal. The accepted diagnosis process involves manually observing a suspicious lesion through a Dermascope (i.e., a magnifying glass), followed by a biopsy....
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14471
更新日期:2020-11-01 00:00:00
abstract:PURPOSE:The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array,...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3694667
更新日期:2012-04-01 00:00:00
abstract:PURPOSE:The aim of this study is to investigate the performance of Sentinel(™), a patient setup verification device based on a laser/camera system, when used on rigid-body phantoms. METHODS:The Sentinel system consists of a scanner unit, containing the laser and the camera, and surface-matching registration software. ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3675973
更新日期:2012-02-01 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:To investigate the critical structure sparing achievable by biological optimization for modulated volumetric arc (VMAT) of head and neck (H&N) cancer. METHODS:Ten H&N VMAT patients who were originally planned and treated with simultaneous integrated boost technique using dose-volume based optimization, were se...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735671
更新日期:2012-06-01 00:00:00
abstract::The physical factors that govern 2D and 3D imaging performance may be understood from quantitative analysis of the spatial-frequency-dependent signal and noise transfer characteristics [e.g., modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3002414
更新日期:2008-12-01 00:00:00
abstract:PURPOSE:A joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12459
更新日期:2017-11-01 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::Ultrasound has been the greatest imaging modality worldwide for many years by equipment purchase value and by number of machines and examinations. It is becoming increasingly the front end imaging modality; serving often as an extension of the physician's fingers. We believe that at the other extreme, high-end systems...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1118/1.2992048
更新日期:2009-02-01 00:00:00
abstract::A new system of radiation dose mapping based on laser heating of thermoluminescent dosimetric plates (TLDP) has been developed. Application of this technique to intraoperative radiotherapy (IORT) has been investigated. Preliminary results show that TLDP are a possible alternative to radiological films and ionization c...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597725
更新日期:1996-08-01 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::Teletherapy with high linear energy transfer radiations (LET), perhaps more than with low LET types, requires careful beam collimation to limit effects to normal structures. Intensity modulated techniques may also hold promise in this regard. Accordingly, a remote computer-controlled, high-resolution multileaf collima...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2760026
更新日期:2007-09-01 00:00:00
abstract:PURPOSE:Partial scan reconstruction (PSR) artifacts are present in myocardial perfusion imaging using dynamic multidetector computed tomography (MDCT). PSR artifacts appear as temporal CT number variations due to inconsistencies in the angular data range used to reconstruct images and compromise the quantitative value ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3665767
更新日期:2012-01-01 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::Current dosimetry protocols for clinical protons do not take into account any secondary electron fluence perturbation in ion chambers. In this work, we performed a systematic study of secondary electron fluence perturbation factors for spherical and cylindrical ion chambers in proton beams (70-250 MeV). The electron f...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1406519
更新日期:2001-10-01 00:00:00
abstract:PURPOSE:To commission and benchmark a vendor-supplied (Varian Medical Systems) Monte Carlo phase-space data for the 6 MV flattening filter free (FFF) energy mode on a TrueBeam linear accelerator for the purpose of quality assurance of clinical volumetric modulated arc therapy (VMAT) treatment plans. A method for render...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4773883
更新日期:2013-02-01 00:00:00
abstract:PURPOSE:Proton computed tomography (pCT) will enable accurate prediction of proton and ion range in a patient while providing the benefit of lower radiation exposure than in x-ray CT. The accuracy of the range prediction is essential for treatment planning in proton or ion therapy and depends upon the detector used to ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4939255
更新日期:2016-02-01 00:00:00
abstract:PURPOSE:Deformable image registration (DIR) is often validated based on a distance-to-agreement (DTA) criterion of automatically propagated anatomical landmarks that were manually identified. Due to human observer variability, however, the performance of the registration method is diluted. The purpose of this study was...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4760990
更新日期:2012-11-01 00:00:00
abstract::The output factor for a therapy photon beam is defined as the dose per monitor unit relative to the dose per monitor unit in a reference field. Convolution models for photon dose calculations yield the dose in units normalized to the incident energy fluence with phantom scatter intrinsically modeled. Output factors ca...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596859
更新日期:1992-03-01 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::Deformable image registration is an important tool for image-guided radiotherapy. Physics-model-based deformable image registration using finite element analysis is one of the methods currently being investigated. The calculation accuracy of finite element analysis is dependent on given boundary conditions, which are ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1774131
更新日期:2004-09-01 00:00:00