Abstract:
PURPOSE:Very fast Monte Carlo (MC) simulations of proton transport have been implemented recently on graphics processing units (GPUs). However, these MCs usually use simplified models for nonelastic proton-nucleus interactions. Our primary goal is to build a GPU-based proton transport MC with detailed modeling of elastic and nonelastic proton-nucleus collisions. METHODS:Using the cuda framework, the authors implemented GPU kernels for the following tasks: (1) simulation of beam spots from our possible scanning nozzle configurations, (2) proton propagation through CT geometry, taking into account nuclear elastic scattering, multiple scattering, and energy loss straggling, (3) modeling of the intranuclear cascade stage of nonelastic interactions when they occur, (4) simulation of nuclear evaporation, and (5) statistical error estimates on the dose. To validate our MC, the authors performed (1) secondary particle yield calculations in proton collisions with therapeutically relevant nuclei, (2) dose calculations in homogeneous phantoms, (3) recalculations of complex head and neck treatment plans from a commercially available treatment planning system, and compared with (GEANT)4.9.6p2/TOPAS. RESULTS:Yields, energy, and angular distributions of secondaries from nonelastic collisions on various nuclei are in good agreement with the (GEANT)4.9.6p2 Bertini and Binary cascade models. The 3D-gamma pass rate at 2%-2 mm for treatment plan simulations is typically 98%. The net computational time on a NVIDIA GTX680 card, including all CPU-GPU data transfers, is ∼ 20 s for 1 × 10(7) proton histories. CONCLUSIONS:Our GPU-based MC is the first of its kind to include a detailed nuclear model to handle nonelastic interactions of protons with any nucleus. Dosimetric calculations are in very good agreement with (GEANT)4.9.6p2/TOPAS. Our MC is being integrated into a framework to perform fast routine clinical QA of pencil-beam based treatment plans, and is being used as the dose calculation engine in a clinically applicable MC-based IMPT treatment planning system. The detailed nuclear modeling will allow us to perform very fast linear energy transfer and neutron dose estimates on the GPU.
journal_name
Med Physjournal_title
Medical physicsauthors
Wan Chan Tseung H,Ma J,Beltran Cdoi
10.1118/1.4921046subject
Has Abstractpub_date
2015-06-01 00:00:00pages
2967-78issue
6eissn
0094-2405issn
2473-4209journal_volume
42pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::A method is presented for calculation of transmission functions for high energy photon beams through patients. These functions are being used in our clinic for prediction of portal dose images (PDIs) which are compared with PDIs measured with an electronic portal imaging device (EPID). The calculations are based on th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598293
更新日期:1998-06-01 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 cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides exce...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4914860
更新日期:2015-04-01 00:00:00
abstract:PURPOSE:Wide bore CT scanners use extended field-of-view (eFOV) reconstruction algorithms to attempt to recreate tissue truncated due to large patient habitus. Radiation therapy planning systems rely on accurate CT numbers in order to correctly plan and calculate radiation dose. This study looks at the impact of eFOV r...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13299
更新日期:2019-02-01 00:00:00
abstract:PURPOSE:To automatically detect and isolate areas of low and high stiffness temporal stability in shear wave elastography (SWE) image sequences and define their impact in chronic liver disease (CLD) diagnosis improvement by means of clinical examination study and deep learning algorithm employing convolutional neural n...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13521
更新日期:2019-05-01 00:00:00
abstract::Attention is given to means of sensing ultrasonic energy distributions over an area. Under the restraints appropiate to real-time imaging of deep body organs, piezoelectric arrays offer the most promising method. Adaptation of integrated circuit techniques to array assembly permits very large arrays of small elements ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594247
更新日期:1976-09-01 00:00:00
abstract:PURPOSE:The quality of tomographic images is directly affected by the system model being used in image reconstruction. An accurate system matrix is desirable for high-resolution image reconstruction, but it often leads to high computation cost. In this work the authors present a maximum a posteriori reconstruction algo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3284980
更新日期:2010-02-01 00:00:00
abstract:PURPOSE:To increase diagnostic accuracy of breast MRI by increasing temporal resolution and more accurately sampling the early kinetics of contrast media uptake. We tested the feasibility of accelerating bilateral breast DCE-MRI by reducing the FOV, allowing aliasing, and unfolding the resulting images. METHODS:Previo...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12747
更新日期:2018-03-01 00:00:00
abstract:PURPOSE:Two diodes which do not require correction factors for small field relative output measurements are designed and validated using experimental methodology. This was achieved by adding an air layer above the active volume of the diode detectors, which canceled out the increase in response of the diodes in small f...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4894728
更新日期:2014-10-01 00:00:00
abstract:PURPOSE:A prototype in-house program was developed to assist deriving image guidance shifts clinically using our 4DCT method for lung SBRT. METHODS:Our in-house prototype program was implemented in MATLAB. The 4D DICOM CT dataset of interest is imported by the program from AW and subsequently accepts input from the us...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735493
更新日期:2012-06-01 00:00:00
abstract::As a potentially important technology for medical x-ray computed tomography (CT), lambda tomography (LT) is to reconstruct a gradient-like image only from local projection data. Based on our recently derived exact fan-beam LT formula, [H. Y. Gu and G. Wang, Int. J. Biomed. Imaging 2006(1), 1-9 (2006)] here we propose ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2348767
更新日期:2006-10-01 00:00:00
abstract::The purpose of this study is to develop a 4D inverse planning strategy capable of controlling the appearance of the implanted fiducial(s) in segmented IMRT fields for cine MV or combined MV/kV image-guided IMRT. This work is focused on enhancing the visibility of the implanted fiducial(s) in 4D IMRT inverse planning, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3121425
更新日期:2009-06-01 00:00:00
abstract::Use of dynamic multileaf collimation (DMLC) for intensity modulated radiation therapy (IMRT) is accelerating. Delivery systems have the ailment of interleaf leakage (IL). This is compounded by the inefficiency of IMRT delivery, estimated to be a factor of 5 for DMLC. With IL on the order of 4%, it is possible to deliv...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1388216
更新日期:2001-08-01 00:00:00
abstract::The bremsstrahlung spectrum from an 8-MeV linear accelerator has been measured using a NaI(T1) spectrometer system. The spectrum shows a low-energy cutoff at 0.4 MeV and the maximum photon energy to be approximately 6% greater than the nominal energy. The maximum emission of energy fluence was 1.6 and 1.8 MeV for meas...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594221
更新日期:1976-05-01 00:00:00
abstract:PURPOSE:A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. METHODS:We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4729708
更新日期:2012-07-01 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::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::We propose the use of conic and cubic surface equations (surfaces of second and third order) to directly approximate the dual-energy equations (the integral equations for the dual-energy log-signal functions, i.e., the negative logarithms of the relative detector signals, considered as functions of the basis-material ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596512
更新日期:1990-05-01 00:00:00
abstract:PURPOSE:In computed tomography (CT), organ dose, effective dose, and risk index can be estimated from volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) using conversion coefficients. Studies have investigated how these coefficients vary across scanner models, scan parameters, and patient size. Howe...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4754584
更新日期:2012-11-01 00:00:00
abstract::The performance of a diode array (Profiler) was evaluated by comparing its enhanced dynamic wedge (EDW) profiles measured at various depths with point measurements using a 0.03 cm3 ionization chamber on a commercial linear accelerator. The Profiler, which covers a 22.5 cm width, was used to measure larger field widths...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598019
更新日期:1997-07-01 00:00:00
abstract:PURPOSE:Prostate biopsy, performed using two-dimensional (2D) transrectal ultrasound (TRUS) guidance, is the clinical standard for a definitive diagnosis of prostate cancer. Histological analysis of the biopsies can reveal cancerous, noncancerous, or suspicious, possibly precancerous, tissue. During subsequent biopsy s...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3298010
更新日期:2010-02-01 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: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::Absorbed doses from main charged-particle beams and charged-particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; microdosimetric ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2767933
更新日期:2007-09-01 00:00:00
abstract:PURPOSE:Intensity modulated proton therapy (IMPT) is sensitive to errors, mainly due to high stopping power dependency and steep beam dose gradients. Conventional margins are often insufficient to ensure robustness of treatment plans. In this article, a method is developed that takes the uncertainties into account duri...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3556559
更新日期:2011-03-01 00:00:00
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: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:PURPOSE:The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file i...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13579
更新日期:2019-07-01 00:00:00
abstract::Techniques have been developed for reducing motion blurring artifacts by using respiratory gated computed tomography (CT) in sinogram space and quantitatively evaluating the artifact reduction. A synthetic sinogram was built from multiple scans intercepting a respiratory gating window. A gated CT image was then recons...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2074187
更新日期:2005-11-01 00:00:00
abstract:PURPOSE:Many clinical applications depend critically on the accurate differentiation and classification of different types of materials in patient anatomy. This work introduces a unified framework for accurate nonlinear material decomposition and applies it, for the first time, in the concept of triple-energy CT (TECT)...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12933
更新日期:2018-07-01 00:00:00