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Radiochromic film

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https://www.readbyqxmd.com/read/27898748/-investigating-the-clinical-applicability-of-ebt2-self-developing-films
#1
Zsuzsánna Zongor, Dalma Béla, Réka Király, Gábor Stelczer, Tibor Major, Csilla Pesznyák
The purpose of the study was to investigate the physical properties of the EBT2 radiochromic films and define the conditions of its clinical applicability. We irradiated the films with different treatment techniques 3D conformal (3DCRT), intensity-modulated (IMRT) and stereotactic body radiotherapy with arc therapy (SBRT), and then compared the data with the dose distribution exported from the treatment planning system (Eclipse). Two film analysis softwares were investigated for the comparison: PTW Mephysto and FilmQA Pro...
November 29, 2016: Magyar Onkologia
https://www.readbyqxmd.com/read/27881295/measuring-dose-from-radiotherapy-treatments-in-the-vicinity-of-a-cardiac-pacemaker
#2
Samuel C Peet, Rachael Wilks, Tanya Kairn, Scott B Crowe
This study investigated the dose absorbed by tissues surrounding artificial cardiac pacemakers during external beam radiotherapy procedures. The usefulness of out-of-field reference data, treatment planning systems, and skin dose measurements to estimate the dose in the vicinity of a pacemaker was also examined. Measurements were performed by installing a pacemaker onto an anthropomorphic phantom, and using radiochromic film and optically stimulated luminescence dosimeters to measure the dose in the vicinity of the device during the delivery of square fields and clinical treatment plans...
November 21, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27842982/in-vivo-skin-dose-measurement-using-moskin-detectors-in-tangential-breast-radiotherapy
#3
W L Jong, N M Ung, J H D Wong, K H Ng, W Z Wan Ishak, R Abdul Malik, V C E Phua, D L Cutajar, P E Metcalfe, A B Rosenfeld, G F Ho
The purpose of this study is to measure patient skin dose in tangential breast radiotherapy. Treatment planning dose calculation algorithm such as Pencil Beam Convolution (PBC) and in vivo dosimetry techniques such as radiochromic film can be used to accurately monitor radiation doses at tissue depths, but they are inaccurate for skin dose measurement. A MOSFET-based (MOSkin) detector was used to measure skin dose in this study. Tangential breast radiotherapies ("bolus" and "no bolus") were simulated on an anthropomorphic phantom and the skin doses were measured...
November 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27782733/technical-note-calibrating-radiochromic-film-in-beams-of-uncertain-quality
#4
Samuel C Peet, Rachael Wilks, Tanya Kairn, Jamie V Trapp, Scott B Crowe
PURPOSE: The dose-response of radiochromic film has been shown to be dependent on the quality of the incident radiation, particularly at low energies. Difficulty therefore arises when a calibration is required for radiation of uncertain energy. This study investigates the ability of a recently published calibration method [see M. Tamponi et al., "A new form of the calibration curve in radiochromic dosimetry. Properties and results," Med. Phys. 43, 4435-4446 (2016)] to reduce the energy-dependence of radiochromic film...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27747975/a-novel-removable-cerrobend-beam-blocking-device-for-radiation-therapy-of-the-canine-head-and-neck-pilot-study
#5
Michael S Kent, Davide Berlato, Isabelle Vanhaezebrouck, Ira K Gordon, Katherine S Hansen, Alain P Theon, Randall W Holt, Earl A Trestrail
Radiation therapy of the head and neck can result in mucositis and other acute affects in the oral cavity. This prospective pilot study evaluated a novel, intraoral, beam-blocking device for use during imaging and therapeutic procedures. The beam-blocking device was made from a metal alloy inserted into a coated frozen dessert mold (Popsicle® Mold, Cost Plus World Market, Oakland, CA). The device was designed so that it could be inserted into an outer shell, which in turn allowed it to be placed or removed depending on the need due to beam configuration...
October 17, 2016: Veterinary Radiology & Ultrasound
https://www.readbyqxmd.com/read/27740945/the-origin-of-the-flatbed-scanner-artifacts-in-radiochromic-film-dosimetry-key-experiments-and-theoretical-descriptions
#6
Andreas A Schoenfeld, Soeren Wieker, Dietrich Harder, Bjoern Poppe
The optical origin of the lateral response and orientation artifacts, which occur when using EBT3 and EBT-XD radiochromic films together with flatbed scanners, has been reinvestigated by experimental and theoretical means. The common feature of these artifacts is the well-known parabolic increase in the optical density OD(x)  =  -log10 I(x)/I 0(x) versus offset x from the scanner midline (Poppinga et al 2014 Med. Phys. 41 021707). This holds for landscape and portrait orientations as well as for the three color channels...
October 14, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27716632/characterization-of-al2o3-optically-stimulated-luminescence-films-for-2d-dosimetry-using-a-6-mv-photon-beam
#7
M F Ahmed, N Shrestha, E Schnell, S Ahmad, M S Akselrod, E G Yukihara
This work evaluates the dosimetric properties of newly developed optically stimulated luminescence (OSL) films, fabricated with either Al2O3:C or Al2O3:C,Mg, using a prototype laser scanning reader, a developed image reconstruction algorithm, and a 6 MV therapeutic photon beam. Packages containing OSL films (Al2O3:C and Al2O3:C,Mg) and a radiochromic film (Gafchromic EBT3) were irradiated using a 6 MV photon beam using different doses, field sizes, with and without wedge filter. Dependence on film orientation of the OSL system was also tested...
October 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27690300/correlation-analysis-between-2d-and-quasi-3d-gamma-evaluations-for-both-intensity-modulated-radiation-therapy-and-volumetric-modulated-arc-therapy
#8
Jung-In Kim, Chang Heon Choi, Hong-Gyun Wu, Jin Ho Kim, Kyubo Kim, Jong Min Park
The aim of this work was to investigate correlations between 2D and quasi-3D gamma passing rates. A total of 20 patients (10 prostate cases and 10 head and neck cases, H&N) were retrospectively selected. For each patient, both intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were generated. For each plan, 2D gamma evaluation with radiochromic films and quasi-3D gamma evaluation with fluence measurements were performed with both 2%/2 mm and 3%/3 mm criteria. Gamma passing rates were grouped together according to delivery techniques and treatment sites...
September 27, 2016: Oncotarget
https://www.readbyqxmd.com/read/27685125/evaluation-of-the-uncertainty-in-an-ebt3-film-dosimetry-system-utilizing-net-optical-density
#9
Elsa Y León Marroquin, José A Herrera González, Miguel A Camacho López, José E Villarreal Barajas, Olivia A García-Garduño
Radiochromic film has become an important tool to verify dose distributions for intensity-modulated radiotherapy (IMRT) and quality assurance (QA) procedures. A new radiochromic film model, EBT3, has recently become available, whose composition and thickness of the sensitive layer are the same as those of previous EBT2 films. However, a matte polyester layer was added to EBT3 to prevent the formation of Newton's rings. Furthermore, the symmetrical design of EBT3 allows the user to eliminate side-orientation dependence...
2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27672625/skin-dosimetry-in-radiotherapy-of-breast-cancer-a-comparison-between-ebt-and-ebt3-radiochromic-films
#10
M T Bahreyni Toosi, N Mohamadian, M Ghorbani, F Khorshidi, F Akbari, C Knaup
OBJECTIVE: Radiochromic EBT3 film is a later generation of radiochromic films. The aim of this study is to compare EBT and EBT3 radiochromic films in radiotherapy fields of breast cancer. METHODS: A RANDO phantom was irradiated by a 6 MV Siemens Primus linac with medial and lateral fields of radiotherapy of breast cancer. Dosimetry was performed in various points in the fields using EBT and EBT3 films. Films were scanned by a Microtek color scanner. Dose values from two films in corresponding points were compared...
June 2016: Journal of Biomedical Physics & Engineering
https://www.readbyqxmd.com/read/27648086/clinical-implementation-of-a-novel-applicator-in-high-dose-rate-brachytherapy-treatment-of-esophageal-cancer
#11
Ivan M Buzurovic, Jorgen L Hansen, Mandar S Bhagwat, Desmond A O'Farrell, Scott Friesen, Thomas C Harris, Antonio L Damato, Robert A Cormack, Neil E Martin, Phillip M Devlin
PURPOSE: In this study, we present the clinical implementation of a novel transoral balloon centering esophageal applicator (BCEA) and the initial clinical experience in high-dose-rate (HDR) brachytherapy treatment of esophageal cancer, using this applicator. MATERIAL AND METHODS: Acceptance testing and commissioning of the BCEA were performed prior to clinical use. Full performance testing was conducted including measurements of the dimensions and the catheter diameter, evaluation of the inflatable balloon consistency, visibility of the radio-opaque markers, congruence of the markers, absolute and relative accuracy of the HDR source in the applicator using the radiochromic film and source position simulator, visibility and digitization of the applicator on the computed tomography (CT) images under the clinical conditions, and reproducibility of the offset...
August 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/27623043/breastdosimetry-of-99m-tc-balloon-in-complementary-radiotherapy
#12
Carla Flávia de Lima, Tarcísio P R Campos
: Dose reinforcement in primary tumor cavity can complement conventional radiotherapy in patients with early breast cancer. In this study, a dosimetric analysis was conducted by pertechnetate-(99m)Tc-filled balloon brachytherapy (TBB). METHODS: Dosimetry based on radiochromic films and on a computational voxel thorax model was performed. Calibration protocol achieved a mathematical relationship between dose and optical density in films placed on the surface at a distance of 0-9cm, 1cm between them, in which dose values were provided by MCNP® code...
August 6, 2016: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/27595366/characterization-of-noise-and-digitizer-response-variability-in-radiochromic-film-dosimetry-impact-on-treatment-verification
#13
Juan Antonio Vera Sánchez, Carmen Ruiz Morales, Antonio González López
PURPOSE: To study how noise and scanner response variability affect radiochromic film dosimetry. METHODS: Five treatment plans were analyzed in this work with two different multichannel protocols: the multichannel algorithm of Mayer et al. and the efficient protocol of Lewis et al. RESULTS AND CONCLUSION: The multichannel protocol of Mayer et al. is not able to compensate variability in scanner response, which is an important issue for radiochromic film dosimetry...
September 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27587043/a-tracking-system-to-calculate-patient-skin-dose-in-real-time-during-neurointerventional-procedures-using-a-biplane-x-ray-imaging-system
#14
V K Rana, S Rudin, D R Bednarek
PURPOSE: Neurovascular interventional procedures using biplane fluoroscopic imaging systems can lead to increased risk of radiation-induced skin injuries. The authors developed a biplane dose tracking system (Biplane-DTS) to calculate the cumulative skin dose distribution from the frontal and lateral x-ray tubes and display it in real-time as a color-coded map on a 3D graphic of the patient for immediate feedback to the physician. The agreement of the calculated values with the dose measured on phantoms was evaluated...
September 2016: Medical Physics
https://www.readbyqxmd.com/read/27587042/approaches-to-reducing-photon-dose-calculation-errors-near-metal-implants
#15
Jessie Y Huang, David S Followill, Rebecca M Howell, Xinming Liu, Dragan Mirkovic, Francesco C Stingo, Stephen F Kry
PURPOSE: Dose calculation errors near metal implants are caused by limitations of the dose calculation algorithm in modeling tissue/metal interface effects as well as density assignment errors caused by imaging artifacts. The purpose of this study was to investigate two strategies for reducing dose calculation errors near metal implants: implementation of metal-based energy deposition kernels in the convolution/superposition (C/S) dose calculation method and use of metal artifact reduction methods for computed tomography (CT) imaging...
September 2016: Medical Physics
https://www.readbyqxmd.com/read/27545010/dosimetric-quality-accuracy-and-deliverability-of-modulated-radiotherapy-treatments-for-spinal-metastases
#16
Tanya Kairn, Daniel Papworth, Scott B Crowe, Jennifer Anderson, David R H Christie
Cancer often metastasizes to the vertebra, and such metastases can be treated successfully using simple, static posterior or opposed-pair radiation fields. However, in some cases, including when re-irradiation is required, spinal cord avoidance becomes necessary and more complex treatment plans must be used. This study evaluated 16 sample intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans designed to treat 6 typical vertebral and paraspinal volumes using a standard prescription, with the aim of investigating the advantages and limitations of these treatment techniques and providing recommendations for their optimal use in vertebral treatments...
2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/27520403/grid-patterns-spatial-inter-scan-variations-and-scanning-reading-repeatability-in-radiochromic-film-dosimetry
#17
I Méndez, Ž Šljivić, R Hudej, A Jenko, B Casar
PURPOSE: When comparing different scans of the same radiochromic film, several patterns can be observed. These patterns are caused by different sources of uncertainty, which affect the repeatability of the scanner. The purpose of this work was to study these uncertainties. METHODS: The variance of the scanner noise, as a function of the pixel position, was studied for different resolutions. The inter-scan variability of the scanner response was analyzed taking into account spatial discrepancies...
September 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27487902/modification-and-validation-of-an-analytical-source-model-for-external-beam-radiotherapy-monte-carlo-dose-calculations
#18
Scott E Davidson, Jing Cui, Stephen Kry, Joseph O Deasy, Geoffrey S Ibbott, Milos Vicic, R Allen White, David S Followill
PURPOSE: A dose calculation tool, which combines the accuracy of the dose planning method (DPM) Monte Carlo code and the versatility of a practical analytical multisource model, which was previously reported has been improved and validated for the Varian 6 and 10 MV linear accelerators (linacs). The calculation tool can be used to calculate doses in advanced clinical application studies. One shortcoming of current clinical trials that report dose from patient plans is the lack of a standardized dose calculation methodology...
August 2016: Medical Physics
https://www.readbyqxmd.com/read/27487885/an-experimental-extrapolation-technique-using-the-gafchromic-ebt3-film-for-relative-output-factor-measurements-in-small-x-ray-fields
#19
Johnny E Morales, Martin Butson, Scott B Crowe, Robin Hill, J V Trapp
PURPOSE: An experimental extrapolation technique is presented, which can be used to determine the relative output factors for very small x-ray fields using the Gafchromic EBT3 film. METHODS: Relative output factors were measured for the Brainlab SRS cones ranging in diameters from 4 to 30 mm(2) on a Novalis Trilogy linear accelerator with 6 MV SRS x-rays. The relative output factor was determined from an experimental reducing circular region of interest (ROI) extrapolation technique developed to remove the effects of volume averaging...
August 2016: Medical Physics
https://www.readbyqxmd.com/read/27487869/use-of-radiochromic-film-as-a-high-spatial-resolution-dosimeter-by-raman-spectroscopy
#20
Jamal Ahmad Mirza, Hyeonsuk Park, So-Yeon Park, Sung-Joon Ye
PURPOSE: Due to increasing demand for high-spatial resolution dosimetry, radiochromic films have been investigated as potential candidates but are often limited by the scanning system, e.g., flatbed optical scanner. In this study, Raman spectroscopy in conjunction with a microscope was selected as an alternative method for high-spatial resolution dosimetry of radiochromic film. METHODS: Unlaminated Gafchromic™ EBT3 films were irradiated with doses between 0 and 50 Gy using 6 MV x-rays of a clinical linear accelerator...
August 2016: Medical Physics
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