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Find video protocols related to scientific articles indexed in Pubmed.
Risk of secondary cancers from scattered radiation during intensity-modulated radiotherapies for hepatocellular carcinoma.
Radiat Oncol
PUBLISHED: 03-17-2014
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To evaluate and compare the risks of secondary cancers from therapeutic doses received by patients with hepatocellular carcinoma (HCC) during intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and tomotherapy (TOMO).
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Proton-radiography-based quality assurance of proton range compensator.
Phys Med Biol
PUBLISHED: 09-03-2013
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The aim of this work was to study the feasibility of proton radiography (pRad) as a patient-specific range compensator (RC) quality assurance (QA) tool and to validate its clinical utility by performing QA on RCs having three kinds of possible defects. In order to achieve pRad for a single EBT film, proton beam currents were modulated with new weighting factors, maximizing the linearity of optical-density-to-thickness ratio. Two RCs, examined to be accurately manufactured as planned, were selected to estimate the feasibility of our pRad. The optical densities of the EBT film on which the RC was irradiated with the modulated proton beam were digitized to pixel values (pv) and then converted to thickness using a thickness-pv calibration curve. The thickness information on the pRad was compared with plan data that had been extracted from treatment planning system. The mean thickness difference (TD) over the flat RC regions was calculated as 0.39 mm, and the standard deviation as 0.22 mm, and the proton scattering effect was analyzed by step phantom measurement. Even proton scattering effected a TD of over 1 mm in the large gradient region, the percentage of pixels over the acceptance criterion was only within 1.11% and 3.49%, respectively, when a 1 mm distance to agreement tolerance limit was applied. The QA results for both precisely and imprecisely manufactured RCs demonstrated the high potential utility and clinical applicability of the pRad-based RC QA tool.
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Estimation of optimal margin for intrafraction movements during frameless brain radiosurgery.
Med Phys
PUBLISHED: 05-03-2013
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To examine the dosimetric effect of intrafraction movements occurred during image-guided frameless brain radiosurgery and to derive the optimal margin recipe to compensate the movement.
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Compensation method for respiratory motion in proton treatment planning for mobile liver cancer.
J Appl Clin Med Phys
PUBLISHED: 03-09-2013
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We evaluated the dosimetric effect of a respiration motion, and sought an effective planning strategy to compensate the motion using four-dimensional computed tomography (4D CT) dataset of seven selected liver patients. For each patient, we constructed four different proton plans based on: (1) average (AVG) CT, (2) maximum-intensity projection (MIP) CT, (3) AVG CT with density override of tumor volume (OVR), and (4) AVG CT with field-specific proton margin which was determined by the range difference between AVG and MIP plans (mAVG). The overall effectiveness of each planning strategy was evaluated by calculating the cumulative dose distribution over an entire breathing cycle. We observed clear differences between AVG and MIP CT-based plans, with significant underdosages at expiratory and inspiratory phases, respectively. Only the mAVG planning strategy was fully successful as the field-specific proton margin applied in the planning strategy complemented both the limitations of AVG and MIP CT-based strategies. These results demonstrated that respiration motion induced significant changes in dose distribution of 3D proton plans for mobile liver cancer and the changes can be effectively compensated by applying field-specific proton margin to each proton field.
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Risk of second cancer from scattered radiation of intensity-modulated radiotherapies with lung cancer.
Radiat Oncol
PUBLISHED: 02-24-2013
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To compare the risk of secondary cancer from scattered and leakage doses following intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with lung cancer.
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Radiochromic film based transit dosimetry for verification of dose delivery with intensity modulated radiotherapy.
Med Phys
PUBLISHED: 02-08-2013
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To evaluate the transit dose based patient specific quality assurance (QA) of intensity modulated radiation therapy (IMRT) for verification of the accuracy of dose delivered to the patient.
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Secondary neutron dose measurement for proton eye treatment using an eye snout with a borated neutron absorber.
Radiat Oncol
PUBLISHED: 01-10-2013
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We measured and assessed ways to reduce the secondary neutron dose from a system for proton eye treatment.
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The effect of a contrast agent on proton beam range in radiotherapy planning using computed tomography for patients with locoregionally advanced lung cancer.
Int. J. Radiat. Oncol. Biol. Phys.
PUBLISHED: 02-06-2011
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We evaluated the effect of a contrast agent (CA) on proton beam range in a treatment planning system (TPS) for patients with locoregionally advanced lung cancer.
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Improved quantitative analysis of mass spectrometry using quadratic equations.
J. Proteome Res.
PUBLISHED: 03-25-2010
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Protein quantification is one of the principal computational problems in mass spectrometry (MS) based proteomics. For robust and trustworthy protein quantification, accurate peptide quantification must be preceded. In recent years, stable isotope labeling has become the most popular method for relative quantification of peptides. However, some stable isotope labeling methods may carry a critical problem, which is an overlap of isotopic clusters. If the mass difference between the light- and heavy-labeled peptides is very small, the overlap of their isotopic clusters becomes larger as the mass of original peptide increases. Here we propose a new algorithm for peptide quantification that separates overlapping isotopic clusters using quadratic equations. It can be easily applied in Trans-Proteomic Pipeline (TPP) instead of XPRESS. For the mTRAQ-labeled peptides obtained by an Orbitrap mass spectrometer, it showed more accurate ratios and better standard deviations than XPRESS. Especially, for the peptides that do not contain lysine, the ratio difference between XPRESS and our algorithm became larger as the peptide masses increased. We expect that this algorithm can also be applied to other labeling methods such as (18)O labeling and acrylamide labeling.
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Proton range uncertainty due to bone cement injected into the vertebra in radiation therapy planning.
Med Dosim
PUBLISHED: 02-18-2010
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We wanted to evaluate the influence of bone cement on the proton range and to derive a conversion factor predicting the range shift by correcting distorted computed tomography (CT) data as a reference to determine whether the correction is needed. Two CT datasets were obtained with and without a bone cement disk placed in a water phantom. Treatment planning was performed on a set of uncorrected CT images with the bone cement disk, and the verification plan was applied to the same set of CT images with an effective CT number for the bone cement disk. The effective CT number was determined by measuring the actual proton range with the bone cement disk. The effects of CT number, thicknesses, and position of bone cement on the proton range were evaluated in the treatment planning system (TPS) to draw a conversion factor predicting the range shift by correcting the CT number of bone cement. The effective CT number of bone cement was 260 Hounsfield units (HU). The calculated proton range for native CT data was significantly shorter than the measured proton range. However, the calculated range for the corrected CT data with the effective CT number coincided exactly with the measured range. The conversion factor was 209.6 [HU · cm/mm] for bone cement and predicted the range shift by approximately correcting the CT number. We found that the heterogeneity of bone cement could cause incorrect proton ranges in treatment plans using CT images. With an effective CT number of bone cement derived from the proton range and relative stopping power, a more actual proton range could be calculated in the TPS. The conversion factor could predict the necessity for CT data correction with sufficient accuracy.
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Prediction of output factor, range, and spread-out bragg peak for proton therapy.
Med Dosim
PUBLISHED: 02-17-2010
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In proton therapy, patient quality assurance (QA) requires measuring the beam range, spread-out Bragg peak (SOBP), and output factor. If these values can be predicted by using sampling measurements or previous QA data to find the correlation between beam setup parameters and measured data, efforts expended on patient QA can be reduced. Using sampling data, we predicted the range, SOBP, and output factor of the proton beam. To obtain sampling data, we measured the range, SOBP, and output factor for 14 data points at each of 24-beam range options, from 4-28 cm. Prediction conformity was evaluated by the difference between predicted and measured patient QA data. Results indicated that for 60% of patients, the values could be predicted within 3% of dose uncertainty.
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Single-dose versus fractionated stereotactic radiotherapy for brain metastases.
Int. J. Radiat. Oncol. Biol. Phys.
PUBLISHED: 01-11-2010
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To evaluate the efficacy of stereotactic radiotherapy in patients with brain metastases by comparing two different treatment regimens, single-dose radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT).
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Characteristics of movement-induced dose reduction in target volume: a comparison between photon and proton beam treatment.
Med Dosim
PUBLISHED: 08-04-2009
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We compared the main characteristics of movement-induced dose reduction during photon and proton beam treatment, based on an analysis of dose-volume histograms. To simulate target movement, a target contour was delineated in a scanned phantom and displaced by 3 to 20 mm. Although the dose reductions to the target in the 2 treatment systems were similar for transverse (perpendicular to beam direction) target motion, they were completely different for longitudinal (parallel to beam direction) target motion. While both modalities showed a relationship between the degree of target shift and the reduction in dose coverage, dose reduction showed a strong directional dependence in proton beam treatment. Clinical simulation of target movement for a prostate cancer patient showed that, although coverage and conformity indices for a 6-mm lateral movement of the prostate were reduced by 9% and 16%, respectively, for proton beam treatment, they were reduced by only 1% and 7%, respectively, for photon treatment. This difference was greater for a 15-mm target movement in the lateral direction, which lowered the coverage and conformity indices by 34% and 54%, respectively, for proton beam treatment, but changed little during photon treatment. In addition, we found that the equivalent uniform dose (EUD) and homogeneity index show similar characteristics during target movement. These results suggest that movement-induced dose reduction differs significantly between photon and proton beam treatment. Attention should be paid to the target margin in proton beam treatment due to the distinct characteristics of heavy ion beams.
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Microscopic gold particle-based fiducial markers for proton therapy of prostate cancer.
Int. J. Radiat. Oncol. Biol. Phys.
PUBLISHED: 02-04-2009
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We examined the feasibility of using fiducial markers composed of microscopic gold particles and human-compatible polymers as a means to overcome current problems with conventional macroscopic gold fiducial markers, such as dose reduction and artifact generation, in proton therapy for prostate cancer.
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Three-dimensional radiochromic film dosimetry of proton clinical beams using a gafchromic EBT2 film array.
Radiat Prot Dosimetry
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In this work, three-dimensional (3D) film-based proton beam measurements were used for the first time to verify the patient-specific radiation dose distribution, beam range and compensator shape. Three passively scattered proton beams and one uniform scanning proton beam were directed onto an acrylic phantom with inserted Gafchromic EBT films. The average gamma index for a comparison of the dose distributions was less than one for 97.2 % of all pixels from the passively scattered proton beams and 98.1 % of all pixels for the uniform scanning proton beams, with a 3 % dose and a 3 mm distance-to-dose agreement tolerance limit. The results also showed that the average percentage of points within the acceptance criteria for proton beam ranges was 94.6 % for the passively scattered proton beams. Both the dose distribution and the proton beam range determined by the 3D EBT film measurement agreed well with the planning system values.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.