Abstract:
:The total system error (TSE) of a CyberKnife® system was measured using two phantom-based methods and one patient-based method. The standard radiochromic film (RCF) end-to-end (E2E) test using an anthropomorphic head and neck phantom and isocentric treatment delivery was used with the 6Dskull, Fiducial and Xsight® spine (XST) tracking methods. More than 200 RCF-based E2E results covering the period from installation in 2006 until 2017 were analyzed with respect to tracking method, system hardware and software versions, secondary collimation system, and years since installation. An independent polymer gel E2E method was also applied, involving a 3D printed head phantom and multiple spherical target volumes widely distributed within the brain. Finally, the TSE was assessed by comparing the delineated target in the planning computed tomography images of a patient treated for a thalamic functional target with the radiation-induced lesion defined on the six-month follow-up magnetic resonance (MR) images. Statistical analysis of the RCF-based TSE results showed mean ± standard deviation values of 0.40 ± 0.18 mm, 0.40 ± 0.19 mm, and 0.55 ± 0.20 mm for the 6Dskull, Fiducial, and XST tracking methods, respectively. Polymer gel TSE values smaller than 0.66 mm were found for seven targets distributed within the brain, showing that the targeting accuracy of the system is sustained even for targets situated up to 80 mm away from the center of the skull. An average clinical TSE value of 0.87 ± 0.25 mm was also measured using the FSE T2 and FLAIR post-treatment MR image data. Analysis of the long-term RCF-based E2E tests showed no changes of TSE over time. This study is the first to report long-term (>10 years) analysis of TSE, TSE measurement for targets positioned at large distances from the virtual machine isocenter, or a clinical assessment of TSE for the CyberKnife system. All of these measurements demonstrate TSE consistently < 1 mm.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Pantelis E,Moutsatsos A,Antypas C,Zoros E,Pantelakos P,Lekas L,Romanelli P,Zourari K,Hourdakis CJdoi
10.1088/1361-6560/aad516subject
Has Abstractpub_date
2018-08-20 00:00:00pages
165015issue
16eissn
0031-9155issn
1361-6560journal_volume
63pub_type
杂志文章abstract::In conventional gating approaches for positron emission tomography (PET), a single number of gates is predetermined for the whole field of view (FOV) regardless of spatially variant motion blurring effects, which compromises image quality by under-gating regions of large motion and over-gating static regions. To achie...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aac71b
更新日期:2018-08-10 00:00:00
abstract::Sparse phased array ultrasound transducers with millimetre length scale elements have previously been proposed for generating hyperthermia but not for imaging. Numerical simulation with a pseudospectral solver was used to investigate: (a) how the position of the maximum pressure in the focal region changed with elemen...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aace07
更新日期:2018-07-16 00:00:00
abstract::A three-dimensional spherical inclusion model that approximates a lesion bonded to a tissue matrix is proposed for biomedical elastography. Analytical formulae describing spatial strain and stress distributions generated in infinite media by uniform loading are given under a linear, homogeneous, isotropic elasticity a...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/43/1/001
更新日期:1998-01-01 00:00:00
abstract::Lung tumors treated in breath-hold are subject to inter- and intra-breath-hold variations, which makes tumor position monitoring during each breath-hold important. A markerless technique is desirable, but limited tumor visibility on kV images makes this challenging. We evaluated if template matching + triangulation ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aac1a9
更新日期:2018-05-29 00:00:00
abstract::Monte Carlo simulations are used to investigate skin dose resulting from chest wall radiotherapy with bolus. A simple model of a female thorax is developed, which includes a 2 mm-thick skin layer. Two representative 6 MV source models are considered: a tangents source model consisting of a parallel opposed pair of med...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab95dc
更新日期:2020-08-11 00:00:00
abstract::A mathematical model has been constructed to simulate the response of cells in vitro to fractionated doses of radiation. The model is capable of describing most of the radiobiological functions that are commonly studied. Input data are measurable cell properties. The details of the model and methods of acquiring the i...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/21/5/011
更新日期:1976-09-01 00:00:00
abstract::The metabolic content of urine from NIH III nude mice (n = 22) was analysed before and after inoculation with human glioblastoma multiforme (GBM) cancer cells. An age- and gender-matched control population (n = 14) was also studied to identify non-tumour-related changes. Urine samples were collected daily for 6 weeks,...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/3/002
更新日期:2011-02-07 00:00:00
abstract::Electron depth-dose curves and spectra have been measured from an experimental accelerator on which both energy and spectral shape could be varied independently. The measurements were made at nominal energies of 6 and 12 MeV, with the energy spread (FWHM) varied from 1.7% to over 10% of average energy. Changes in dept...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/28/12/005
更新日期:1983-12-01 00:00:00
abstract::Catheter-based ultrasound devices provide a method to deliver 3D conformable heating integrated with HDR brachytherapy delivery. Theoretical characterization of heating patterns was performed to identify implant strategies for these devices which can best be used to apply hyperthermia to cervical cancer. A constrained...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/13/014
更新日期:2011-07-07 00:00:00
abstract::This is a review of the relatively recently developed field of intravascular brachytherapy of coronary arteries. It presents a brief overview of the discipline of coronary angioplasty describing the problem of restenosis and discusses the potential for ionizing radiation to overcome this problem. It examines the vario...
journal_title:Physics in medicine and biology
pub_type: 杂志文章,评审
doi:10.1088/0031-9155/47/4/201
更新日期:2002-02-21 00:00:00
abstract::The Compton camera is an imaging device which has been proposed to detect prompt gammas (PGs) produced by proton-nuclear interactions within tissue during proton beam irradiation. Compton-based PG imaging has been developed to verify proton ranges because PG rays, particularly characteristic ones, have strong correlat...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aab737
更新日期:2018-04-19 00:00:00
abstract::Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) sy...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/5/013
更新日期:2009-03-07 00:00:00
abstract::The sensitivity and detection limit for measurements of the concentration of cadmium in the kidney cortex of man in vivo have been investigated using the technique of X-ray fluorescence. An 11 GB1 241Am source was used to generate the characteristic K alpha X-rays of cadmium. The variation in the sensitivity for the d...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/26/1/004
更新日期:1981-01-01 00:00:00
abstract::It is not feasible to define very small or complex organs and tissues in the current voxel-type adult reference computational phantoms of the International Commission on Radiological Protection (ICRP), which limit dose coefficients for weakly penetrating radiations. To address the problem, the ICRP is converting the v...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5b72
更新日期:2017-03-21 00:00:00
abstract::Successful radiotherapy treatment depends heavily upon the accuracy of patient geometry captured during treatment simulation using computed tomography (CT) scans. Radiotherapy patients are often scanned under free breathing, and respiratory motion can cause severe artifacts in CT scans, including shortening, elongatio...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/3/018
更新日期:2009-02-07 00:00:00
abstract::This work applies a previously developed analytical algorithm to the reconstruction problem in a rotating multi-segment slant-hole (RMSSH) SPECT system. The RMSSH collimator has greater detection efficiency than the parallel-hole collimator with comparable spatial resolution at the expense of limited common volume-of-...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/13/024
更新日期:2009-07-07 00:00:00
abstract::Measurements of patient entrance surface dose rate provide valuable data for interpreting results from dose-area product studies on fluoroscopic x-ray equipment. Methods for measurement of entrance surface dose rate with backscatter and incident dose rate without backscatter have been investigated. Entrance surface do...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/40/5/008
更新日期:1995-05-01 00:00:00
abstract::Many models exist for predicting toxicities based on dose-volume histograms (DVHs) or dose-surface histograms (DSHs). This approach has several drawbacks as firstly the reduction of the dose distribution to a histogram results in the loss of spatial information and secondly the bins of the histograms are highly correl...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/7/013
更新日期:2011-04-07 00:00:00
abstract::Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is a valuable tool for assessing treatment response to novel cancer therapeutics. With appropriate data acquisition, quantitative functional parameter estimates can be obtained by fitting a model to the data. This research focuses on applying a dual-input ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/7/023
更新日期:2009-04-07 00:00:00
abstract::Two new detectors (0.015 cm3 ion chamber from PTW, 0.6 mm diameter diode from Scanditronix AB) designed specifically for use in small stereotactic fields were compared against similar, more routine, detectors (0.125 cm3 ion chamber, parallel plate chamber, shielded and unshielded diodes and film). Percentage depth dos...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/9/303
更新日期:1999-09-01 00:00:00
abstract::Imaging technologies that allow non-radiative visualization and quantification of apoptosis have a great potential for assessing therapy response, early diagnosis, and disease monitoring. Magnetic particle imaging (MPI), the direct imaging of magnetic nanoparticles as positive contrast agent and sole signal source, en...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/abad7c
更新日期:2020-09-24 00:00:00
abstract::We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized....
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/1/301
更新日期:2002-01-07 00:00:00
abstract::IMRT optimization is an iterative process in which many dose calculations may be necessary. A fast and accurate dose calculation engine is essential for the optimization program to converge to a reliable solution in a reasonable time. Previously we developed a fast dose calculation method for IMRT optimization based o...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/19/011
更新日期:2004-10-07 00:00:00
abstract::Stroke lesion volume is a key radiologic measurement in assessing prognosis of acute ischemic stroke (AIS) patients. The aim of this paper is to develop an automated segmentation method for accurately segmenting follow-up ischemic and hemorrhagic lesion from multislice non-contrast CT (NCCT) volumes of AIS patients. T...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aba166
更新日期:2020-11-05 00:00:00
abstract::In this paper we present a novel method of reducing the dosimetric effects of the finite leaf width of a multileaf collimator (MLC) in conformal and intensity modulated radiotherapy (IMRT). This is achieved by decomposing the required high-resolution fluence distribution into two orthogonal components, which are deliv...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/45/3/304
更新日期:2000-03-01 00:00:00
abstract::We have developed a model using Monte Carlo methods to simulate x-ray mammography. All possible physical processes of interaction of x-rays with matter have been taken into account. A simplified geometry of the mammographic apparatus has been considered along with a software phantom of compressed breast. The phantom m...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/43/11/012
更新日期:1998-11-01 00:00:00
abstract::A method for simulating spot-scanned delivery to a moving tumour was developed which uses patient-specific image and plan data. The magnitude of interplay effects was investigated for two patient cases under different fractionation and respiratory motion variation scenarios. The use of volumetric rescanning for motion...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/20/003
更新日期:2011-10-21 00:00:00
abstract::Determining plaque vulnerability is critical when selecting the most suitable treatment for patients with atherosclerotic plaque. Currently, clinical non-invasive ultrasound-based methods for plaque characterization are limited to visual assessment of plaque morphology and new quantitative methods are needed. In this ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/60/8/3151
更新日期:2015-04-21 00:00:00
abstract::Delivery of pencil beam scanning (PBS) requires the on-line measurement of several beam parameters. If the measurement is outside of specified tolerances and a binary threshold algorithm is used, the beam will be paused. Given instrumentation and statistical noise such a system can lead to many pauses which could incr...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/1/400
更新日期:2016-01-07 00:00:00
abstract::A dual-ended readout PET detector based on two Hamamatsu 16 × 16 arrays of 1 × 1 mm2 SiPMs coupled to both ends of a 25 × 25 array of 0.69 × 0.69 × 20 mm3 polished LYSOs was evaluated in terms of flood histogram, energy resolution, timing resolution, and DOI resolution. The SiPM arrays have a pitch size of 1.2 mm. Eac...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab9fc9
更新日期:2020-08-19 00:00:00