Abstract:
PURPOSE:Tumor motion during radiotherapy can cause a reduction in target dose coverage and an increase in healthy tissue exposure. Tumor motion is not strictly translational and often exhibits complex six degree-of-freedom (6DoF) translational and rotational motion. Although the dosimetric impact of prostate tumor translational motion is well investigated, the dosimetric impact of 6DoF motion has only been studied with simulations or dose reconstruction. This study aims to experimentally quantify the dose error caused by 6DoF motion. The experiment was designed to test the hypothesis that 6DoF motion would cause larger dose errors than translational motion alone through gamma analyses of two-dimensional film measurements. METHODS:Four patient-measured intrafraction prostate motion traces and four VMAT 7.25 Gy/Fx SBRT treatment plans were selected for the experiment. The traces represented typical motion patterns, including small-angle rotations (<4°), transient movement, persistent excursion, and erratic rotations (>6°). Gafchromic film was placed inside a custom-designed phantom, held by a high-precision 6DoF robotic arm for dose measurements in the coronal plane during treatment delivery. For each combination of the motion trace and treatment plan, two film measurements were made, one with 6DoF motion and the other with the three-dimensional (3D) translation components of the same trace. A gamma pass rate criteria of 2% relative dose/2 mm distance-to-agreement was used in this study and evaluated for each measurement with respect to the static reference film. Two test thresholds, 90% and 50% of the reference dose, were applied to investigate the difference in dose coverage for the PTV region and surrounding areas, respectively. The hypothesis was tested using a Wilcoxon signed-rank test. RESULTS:For each of the 16 plan and motion trace pairs, a reduction in the gamma pass rate was observed for 6DoF motion compared with 3D translational motion. With 90% gamma-test threshold, the reduction was 5.8% ± 7.1% (P < 0.01). With 50% gamma-test threshold, the reduction was 4.1% ± 4.8% (P < 0.01). CONCLUSION:For the first time, the dosimetric impact of intrafraction prostate rotation during SBRT treatment was measured experimentally. The experimental results support the hypothesis that 6DoF tumor motion causes higher dose error than translation motion alone.
journal_name
Med Physjournal_title
Medical physicsauthors
Shi K,Dipuglia A,Booth J,Alnaghy S,Kyme A,Keall P,Nguyen DTdoi
10.1002/mp.14502subject
Has Abstractpub_date
2020-12-01 00:00:00pages
6068-6076issue
12eissn
0094-2405issn
2473-4209journal_volume
47pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::A fully automatic radiophotoluminescent glass rod dosimeter (GRD) system has recently become commercially available. This article discusses the dosimetric properties of the GRD including uniformity and reproducibility of signal, dose linearity, and energy and directional dependence in high-energy photon beams. In addi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1758351
更新日期:2004-07-01 00:00:00
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, deflectio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3539623
更新日期:2011-02-01 00:00:00
abstract:PURPOSE:To provide a fast computational method, based on the proximal graph solver (POGS) - A convex optimization solver using the alternating direction method of multipliers (ADMM), for calculating an optimal treatment plan in rotating shield brachytherapy (RSBT). RSBT treatment planning has more degrees of freedom th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12486
更新日期:2017-10-01 00:00:00
abstract:PURPOSE:Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenienc...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3566067
更新日期:2011-04-01 00:00:00
abstract:PURPOSE:Efficient and accurate segmentations of 3D end-firing transrectal ultrasound (TRUS) images play an important role in planning of 3D TRUS guided prostate biopsy. However, poor image quality of the input 3D TRUS images, such as strong imaging artifacts and speckles, often makes it a challenging task to extract th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4906129
更新日期:2015-02-01 00:00:00
abstract:PURPOSE:The accuracy and precision of computed tomography (CT) pulmonary ventilation imaging with conventional CT scanners are limited by breathing variations. We propose a method to correct for the effect of breathing variations in CT ventilation imaging based on external respiratory signals acquired throughout a scan...
journal_title:Medical physics
pub_type: 临床试验,杂志文章
doi:10.1002/mp.12634
更新日期:2018-01-01 00:00:00
abstract::The authors describe a method for directly digitizing optical images with a photostimulable phosphor (PSP) system. A PSP plate is initially charged with an exposure to a uniform x-ray field, and is then exposed to an optical image which discharges the plate in relation to the amount of incident light. Two applications...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596917
更新日期:1992-07-01 00:00:00
abstract:PURPOSE:To evaluate a simple, semi-automated lung mass estimation method on CT scans from a variety of acquisition techniques for mass correction of MIRD dose estimates. METHODS:CT scans from ten patients undergoing stereotactic body radiation therapy treatment planning on a GE DST PET/CT scanner were analyzed retrosp...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734654
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (M...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4868693
更新日期:2014-04-01 00:00:00
abstract::The assessment of the radiation dose to internal organs or to an embryo or fetus is required on occasion for risk assessment or for comparing imaging studies. Limited resources hinder the ability to accurately assess the radiation dose received to locations outside the tissue volume actually scanned during computed to...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1312809
更新日期:2000-10-01 00:00:00
abstract::Gd2O2S phosphor screens between 250 and 1000 mg/cm2 thick were evaluated for use in megavoltage imaging systems. The phosphor layers were placed on brass plates ranging from 1 to 5 mm thick, each with and without an optical back reflector (white paint). Light output and spatial resolution were measured at 6- and 23-MV...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597209
更新日期:1994-08-01 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:PURPOSE:The aim of this paper is to investigate the accuracy of a laser∕camera surface imaging system (Sentinel) when used on patients treated in the thorax or pelvic regions and to evaluate system employment conditions and patient setup procedures that provide more accurate results. METHODS:The system was tested on t...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4769428
更新日期:2013-01-01 00:00:00
abstract::A new energy selective detector for dual energy computed radiography has been developed that combines many of the advantages of x-ray tube voltage switching and single exposure double screen detectors. The new active detector utilizes electro-optical modulation of the response of the storage phosphor screens to allow ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597831
更新日期:1996-10-01 00:00:00
abstract::Available deformable registration methods are often inaccurate over large organ variation encountered, for example, in the rectum and bladder. The authors developed a novel approach to accurately and effectively register large deformations in the prostate region for adaptive radiation therapy. A software tool combinin...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3095777
更新日期:2009-04-01 00:00:00
abstract:PURPOSE:To investigate how the setting of optimization parameters, fractional dose and tuning structure in tomotherapy treatment planning affects plan dosimetric quality and treatment efficiency. METHODS:A digital phantom to simulate head and neck radiotherapy was constructed for this study. Tumor was 10cm long C-shap...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735724
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:To characterize the radiation dose and three-dimensional (3D) imaging performance of a recently developed mobile, isocentric C-arm equipped with a flat-panel detector (FPD) for intraoperative cone-beam computed tomography (CBCT) (Cios Spin 3D, Siemens Healthineers) and to identify potential improvements in 3D i...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13983
更新日期:2020-03-01 00:00:00
abstract:PURPOSE:Identification of calcifications and hemorrhages is essential for the etiological diagnosis of cerebral lesions. The purpose of this work was to develop a robust method for characterization of para- and diamagnetic intracerebral lesions based on clinical gradient-echo magnetic resonance phase data acquired at 1...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3481505
更新日期:2010-10-01 00:00:00
abstract::In this paper, a unified framework of iterative algebraic reconstruction for emission computed tomography (ECT) and its application to positron emission tomography (PET) is presented. The unified framework is based on an algebraic image restoration model and contains conventional iterative algebraic reconstruction alg...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596954
更新日期:1993-11-01 00:00:00
abstract:PURPOSE:Scatter contamination in cone-beam computed tomography (CBCT) degrades the image quality by introducing shading artifacts. A moving-blocker-based approach has been proposed to simultaneously estimate scatter and reconstruct the complete volume within field of view (FOV) from a single CBCT scan. Promising result...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4811086
更新日期:2013-07-01 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::A general expression is derived for the NMR signal from a fluid undergoing random directional flow such as encountered within the microcirculation. The dependence of the echo amplitude on flow velocity, sample morphology, and experimental parameters are described in terms of a temporal velocity autocorrelation functio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597170
更新日期:1994-04-01 00:00:00
abstract:PURPOSE:To investigate the acoustic radiation due to eddy current-cryostat interactions and perform a qualitative analysis on noise reduction methods. METHODS:In order to evaluate the sound pressure level (SPL) of the eddy current induced warm bore wall vibration, a Finite Element (FE) model was created to simulate th...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12261
更新日期:2017-06-01 00:00:00
abstract::Monte Carlo simulation dosimetry is used to compare 169Yb to 192Ir for breast high dose rate (HDR) brachytherapy applications using multiple catheter implants. Results for bare point sources show that while 169Yb delivers a greater dose rate per unit air kerma strength at the radial distance range of interest to brach...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2392408
更新日期:2006-12-01 00:00:00
abstract::The physical imaging performance of ST-V, ST-VA, and ST-VN computed radiography image plates, read with a Philips AC3 acquisition system, was investigated at 70 kVp with 0.5 mm of copper beam filtration for four different entrance air kerma values: 0.5, 2.6, 26, and 260 micro Gy. Measurements included characteristic r...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.598412
更新日期:1998-11-01 00:00:00
abstract:PURPOSE:In a recent paper by Bouchard et al. [Med. Phys. 36(10), 4654-4663 (2009)], a theoretical model of quality correction factors for idealistic so-called plan-class specific reference (PCSR) fields was proposed. The reasoning was founded on the definition of PCSR fields made earlier by Alfonso et al. [Med. Phys. 3...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3684952
更新日期:2012-03-01 00:00:00
abstract::A new scheme, called direct aperture deformation (DAD), for online correction of interfraction geometric uncertainties under volumetric imaging guidance is presented. Using deformable image registration, the three-dimensional geometric transformation matrix can be derived that associates the planning image set and the...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2374675
更新日期:2006-12-01 00:00:00
abstract:BACKGROUND:X-ray dark-field radiography could enhance mammography by providing more information on imaged tissue and microcalcifications. The dark field signal is a measure of small angle scattering and can thus provide additional information on the imaged materials. This information can be useful for material distinct...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14043
更新日期:2020-04-01 00:00:00
abstract:PURPOSE:Intensity-Modulated Radiation Therapy (IMRT), including its variations (including IMRT, Volumetric Arc Therapy (VMAT), and Tomotherapy), is a widely used and critically important technology for cancer treatment. It is a knowledge-intensive technology due not only to its own technical complexity, but also to the...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1002/mp.13526
更新日期:2019-06-01 00:00:00
abstract:PURPOSE:The objectives are: (i) assess the development of the impedance of some arteries during the first decades of life; (ii) determine the influence of pulse rate in arterial impedance; (iii) compare the structure of some arterial segments with optimized structures with respect to blood flow; and (iv) explain the el...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4876379
更新日期:2014-06-01 00:00:00