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Gafchromic film

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https://www.readbyqxmd.com/read/28513854/verification-of-dose-profiles-generated-by-the-convolution-algorithm-of-the-gamma-knife-%C3%A2-radiosurgery-planning-system
#1
Hyun-Tai Chung, Jeong-Hoon Park, Kook Jin Chun
PURPOSE: A convolution algorithm that takes into account electron-density inhomogeneity was recently introduced to calculate dose distributions for the Gamma Knife (GK) Perfexion(™) treatment planning program. The accuracies of the dose distributions computed using the convolution method were assessed using an anthropomorphic phantom and film dosimetry. METHODS: Absorbed-dose distributions inside a phantom (CIRS Radiosurgery Head Phantom, Model 605) were calculated using the convolution method of the GK treatment-planning software (Leksell Gamma Plan(®) version 10...
May 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28479873/comparison-of-surface-dose-delivered-by-7%C3%A2-mv-unflattened-and-6%C3%A2-mv-flattened-photon-beams
#2
Ashokkumar Sigamani, Arunai Nambiraj
AIM: The purpose of this study is to determine the central-axis dose in the buildup region and the surface dose delivered by a 6 MV flattened photon beam (6 MV-FB) and a higher energy unflattened (7 MV-FFF) therapeutic photon beam for different-sized square fields with open fields and modifying filters. MATERIALS AND METHODS: The beams are produced by a Siemens Artiste linear accelerator with a NACP-02 ionization chamber and the dose is measured by using GafChromic film and two different, commonly used, dosimeters: a p-type photon semiconductor dosimeter (PFD) and a cylindrical ionization chamber (CC13)...
May 2017: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/28470819/tuning-of-acurosxb-source-size-setting-for-small-intracranial-targets
#3
Stephen J Gardner, Siming Lu, Chang Liu, Ning Wen, Indrin J Chetty
This study details a method to evaluate the source size selection for small field intracranial stereotactic radiosurgery (SRS) deliveries in Eclipse treatment planning system (TPS) for AcurosXB dose calculation algorithm. Our method uses end-to-end dosimetric data to evaluate a total of five source size selections (0.50 mm, 0.75 mm, 1.00 mm, 1.25 mm, and 1.50 mm). The dosimetric leaf gap (DLG) was varied in this analysis (three DLG values were tested for each scenario). We also tested two MLC leaf designs (standard and high-definition MLC) and two delivery types for intracranial SRS (volumetric modulated arc therapy [VMAT] and dynamic conformal arc [DCA])...
May 4, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28464743/monte-carlo-simulations-of-a-low-energy-proton-beamline-for-radiobiological-experiments
#4
Tordis J Dahle, Anne Marit Rykkelid, Camilla H Stokkevåg, Andrea Mairani, Andreas Görgen, Nina J Edin, Eivind Rørvik, Lars Fredrik Fjæra, Eirik Malinen, Kristian S Ytre-Hauge
BACKGROUND: In order to determine the relative biological effectiveness (RBE) of protons with high accuracy, radiobiological experiments with detailed knowledge of the linear energy transfer (LET) are needed. Cell survival data from high LET protons are sparse and experiments with low energy protons to achieve high LET values are therefore required. The aim of this study was to quantify LET distributions from a low energy proton beam by using Monte Carlo (MC) simulations, and to further compare to a proton beam representing a typical minimum energy available at clinical facilities...
June 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28457741/commissioning-of-applicator-guided-stereotactic-body-radiation-therapy-boost-with-high-dose-rate-brachytherapy-for-advanced-cervical-cancer-using-radiochromic-film-dosimetry
#5
Saad Aldelaijan, Shada Wadi-Ramahi, Ahmad Nobah, Belal Moftah, Slobodan Devic, Noha Jastaniyah
PURPOSE: To describe an EBT3 GAFCHROMIC film-based dosimetry method to be used in commissioning of a combined HDR brachytherapy (HDRB) and stereotactic body radiation therapy (SBRT) boost for treatment of advanced cervical cancer involving extensive residual disease after external beam treatment. METHODS AND MATERIALS: A cube phantom was designed to firmly fit an intrauterine tandem applicator and EBT3 radiochromic film pieces. A high-risk clinical target volume (CTVHR, Total) was contoured with an extended arm at one side...
April 27, 2017: Brachytherapy
https://www.readbyqxmd.com/read/28436134/measurement-of-skin-surface-dose-distributions-in-radiation-therapy-using-poly-vinyl-alcohol-cryogel-dosimeters
#6
Molham M Eyadeh, Marcin Wierzbicki, Kevin R Diamond
In external beam radiation therapy (EBRT), skin dose measurement is important to evaluate dose coverage of superficial target volumes. Treatment planning systems (TPSs) are often inaccurate in this region of the patient, so in vivo measurements are necessary for skin surface dose estimation. In this work, superficial dose distributions were measured using radiochromic translucent poly(vinyl alcohol) cryogels. The cryogels simultaneously served as bolus material, providing the necessary buildup to achieve the desired superficial dose...
April 24, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28433589/low-dose-out-of-field-radiotherapy-part-1-measurement-of-scattered-doses
#7
M Kruszyna, S Adamczyk, A Skrobała, M Skórska, W Suchorska, K Zaleska, A Kowalik, W Jackowiak, J Malicki
PURPOSE: To measure out-of-field doses in a phantom model to better quantify this radiation. MATERIAL AND METHODS: The individual contribution of photons and neutrons to the total out-of-field dose for 6 MV and 20 MV photons at open beam were measured in a purpose-designed water phantom. Radiation doses were measured at seven separate points (P1-P7) in the phantom with thermoluminescent detectors (TLD 100, 600, and 700) and GAFchromic™ EBT films. RESULTS: At a prescribed dose of 75Gy to the isocentre, the photon dose level in the close-to-field area (P2) ranged from 2...
April 19, 2017: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28427800/the-effect-of-optune%C3%A2-tumor-treating-fields-transducer-arrays-on-skin-radiation-dose-during-radiotherapy
#8
Edward Bender, Kevin Kozak, Steven Howard, Lori Hayes, John Bayouth, H Ian Robins
A Phase 3 clinical study demonstrated that the addition of 200kHz Tumor Treating Fields (TTF) to temozolomide in the post-radiation (RT) phase of therapy in newly diagnosed glioblastoma increases progression free and overall survival (resulting in FDA and European Union approval). Preclinical studies have demonstrated the ability of TTF to act as a radiosensitizer, suggesting concurrent TTF and RT may have clinical utility. The removal and replacement of TTF transducer arrays from the scalps of patients on a daily basis, i...
April 17, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28370086/modeling-the-dose-dependence-of-the-vis-absorption-spectrum-of-ebt3-gafchromic-%C3%A2-films
#9
Maarten Bert Callens, Wouter Crijns, Tom Depuydt, Karin Haustermans, Frederik Maes, Emiliano D'Agostino, Martine Wevers, Helge Pfeiffer, Koen Van Den Abeele
PURPOSE: The aim of this work is to model the dose dependence of the darkening of GafChromic(™) EBT3 films by combining the optical properties of the polydiacetylene polymer phases, and a modified version of the single-hit model, which will take the stick-like shape of the monomer microcrystals into account. Second, a comparison is made between the quantification of the film darkening by flatbed scanning and by UV-vis absorption spectroscopy. METHOD: GafChromic(™) EBT3 films were irradiated with a 6 MV photon beam at dose levels between 0 and 50 Gy...
March 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28353447/on-the-experimental-validation-of-model-based-dose-calculation-algorithms-for-192-ir-hdr-brachytherapy-treatment-planning
#10
Eleftherios P Pappas, Emmanouil Zoros, Argyris Moutsatsos, Vasiliki Peppa, Kyveli Zourari, Pantelis Karaiskos, Panagiotis Papagiannis
There is an acknowledged need for the design and implementation of physical phantoms appropriate for the experimental validation of model-based dose calculation algorithms (MBDCA) introduced recently in (192)Ir brachytherapy treatment planning systems (TPS), and this work investigates whether it can be met. A PMMA phantom was prepared to accommodate material inhomogeneities (air and Teflon), four plastic brachytherapy catheters, as well as 84 LiF TLD dosimeters (MTS-100M 1  ×  1  ×  1 mm(3) microcubes), two radiochromic films (Gafchromic EBT3) and a plastic 3D dosimeter (PRESAGE)...
May 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28338819/unlaminated-gafchromic-ebt3-film-for-ultraviolet-radiation-monitoring
#11
David Welch, Gerhard Randers-Pehrson, Henry M Spotnitz, David J Brenner
Measurement of ultraviolet (UV) radiation is important for human health, especially with the expanded usage of short wavelength UV for sterilization purposes. This work examines unlaminated Gafchromic EBT3 film for UV radiation monitoring. The authors exposed the film to select wavelengths in the UV spectrum, ranging from 207 to 328 nm, and measured the change in optical density. The response of the film is wavelength dependent, and of the wavelengths tested, the film was most sensitive to 254 nm light, with measurable values as low as 10 µJ/cm2...
February 27, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28325019/frameless-stereotactic-radiosurgery-fsrs-end-to-end-test-with-ebt-xd-gafchromic-film
#12
Yulin Song, Ceferino Obcemea, Boris Mueller, Borys Mychalczak
Frame-based stereotactic radiosurgery (SRS) has been widely used to treat functional disorders, vascular lesions, and primary benign and malignant tumors. Recently, SRS is being increasingly used to treat solitary brain metastases. However, due to its highly invasive nature, frame-based SRS is being gradually replaced by frameless SRS (fSRS). fSRS aims at improving patient comfort and achieving stable patient immobilization with non-invasive means and accurate target localization with image guidance technique...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28303745/grid-therapy-using-high-definition-multileaf-collimators-realizing-benefits-of-the-bystander-effect
#13
Valery Peng, Natalka Suchowerska, Linda Rogers, Elizabeth Claridge Mackonis, Samantha Oakes, David R McKenzie
BACKGROUND: In microbeam radiotherapy (MRT), parallel arrays of high-intensity synchrotron x-ray beams achieve normal tissue sparing without compromising tumor control. Grid-therapy using clinical linacs has spatial modulation on a larger scale and achieves promising results for palliative treatments of bulky tumors. The availability of high definition multileaf collimators (HDMLCs) with 2.5 mm leaves provides an opportunity for grid-therapy to more closely approach MRT. However, challenges to the wider implementation of grid-therapy remain because spatial modulation of the target volume runs counter to current radiotherapy practice and mechanisms for the beneficial effects of MRT are not fully understood...
March 17, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28300373/sum-signal-dosimetry-a-new-approach-for-high-dose-quality-assurance-with-gafchromic-ebt3
#14
Davide Cusumano, Maria Luisa Fumagalli, Francesco Ghielmetti, Linda Rossi, Giuliano Grossi, Raffaella Lanzarotti, Laura Fariselli, Elena De Martin
Gafchromic EBT3 film dosimetry in radiosurgery (RS) and hypofractionated radiotherapy (HRT) is complicated by the limited film accuracy at high fractional doses. The aim of this study is to develop and evaluate sum signal (SS) film dosimetry to increase dose resolution at high fractional doses, thus allowing for use of EBT3 for dose distribution verification of RS/HRT treatments. To characterize EBT3 dose-response, a calibration was performed in the dose range 0.44-26.43 Gy. Red (RC) and green (GC) channel net optical densities were linearly added to produce the SS...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297418/characterization-of-a-2-5-mv-inline-portal-imaging-beam
#15
James L Gräfe, Jennifer Owen, J Eduardo Villarreal-Barajas, Rao F H Khan
A new megavoltage (MV) energy was recently introduced on Varian TrueBeam linear accelerators for imaging applications. This work describes the experimental characterization of a 2.5 MV inline portal imaging beam for commissioning, routine clinical use, and quality assurance purposes. The beam quality of the 2.5 MV beam was determined by measuring a percent depth dose, PDD, in water phantom for 10×10 cm2 field at source-to-surface distance 100 cm with a CC13 ion chamber, plane parallel Markus chamber, and GafChromic EBT3 film...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297357/correction-of-nonuniformity-error-of-gafchromic-ebt2-and-ebt3
#16
Toshizo Katsuda, Rumi Gotanda, Tatsuhiro Gotanda, Takuya Akagawa, Nobuyoshi Tanki, Tadao Kuwano, Kouichi Yabunaka
This study investigates an X-ray dose measurement method for computed tomography using Gafchromic films. Nonuniformity of the active layer is a major problem in Gafchromic films. In radiotherapy, nonuniformity error is reduced by applying the double-exposure technique, but this is impractical in diagnostic radiology because of the heel effect. Therefore, we propose replacing the X-rays in the double-exposure technique with ultraviolet (UV)-A irradiation of Gafchromic EBT2 and EBT3. To improve the reproducibility of the scan position, Gafchromic EBT2 and EBT3 films were attached to a 3-mm-thick acrylic plate...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297335/on-the-accuracy-of-dose-prediction-near-metal-fixation-devices-for-spine-sbrt
#17
Zhangkai J Cheng, Regina M Bromley, Brad Oborn, Martin Carolan, Jeremy T Booth
The metallic fixations used in surgical procedures to support the spine mechanically usually consist of high-density materials. Radiation therapy to palliate spinal cord compression can include prophylactic inclusion of potential tumor around the site of such fixation devices. Determination of the correct density and shape of the spine fixation device has a direct effect on the dose calculation of the radiation field. Even with the application of modern computed tomography (CT), under- or overestimation of dose, both immediately next to the device and in the surrounding tissues, can occur due to inaccuracies in the dose prediction algorithm...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297311/treatment-planning-for-metals-using-an-extended-ct-number-scale
#18
John P Mullins, Michael P Grams, Michael G Herman, Debra H Brinkmann, John A Antolak
Metal implants which saturate the CT number scale may require dosimetrist and physicist involvement to manually contour and assign an appropriate value to the metal for accurate dose calculation. This study investigated dose calculation based directly on extended CT scale images for different metals and geometries. The aim was to evaluate extended CT accuracy as a suitable alternative to standard CT methods in the presence of high-Z materials and artifacts, despite the reduced HU resolution of extended CT. Gafchromic film measurements were made for comparison to calculated doses...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297303/experimental-evaluation-of-a-gpu-based-monte-carlo-dose-calculation-algorithm-in-the-monaco-treatment-planning-system
#19
Moti R Paudel, Anthony Kim, Arman Sarfehnia, Sayed B Ahmad, David J Beachey, Arjun Sahgal, Brian M Keller
A new GPU-based Monte Carlo dose calculation algorithm (GPUMCD), developed by the vendor Elekta for the Monaco treatment planning system (TPS), is capable of modeling dose for both a standard linear accelerator and an Elekta MRI linear accelerator. We have experimentally evaluated this algorithm for a standard Elekta Agility linear accelerator. A beam model was developed in the Monaco TPS (research version 5.09.06) using the commissioned beam data for a 6 MV Agility linac. A heterogeneous phantom representing several scenarios - tumor-in-lung, lung, and bone-in-tissue - was designed and built...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297290/gafchromic-ebt-xd-film-dosimetry-characterization-in-high-dose-volumetric-modulated-arc-therapy
#20
Hideharu Miura, Shuichi Ozawa, Fumika Hosono, Naoki Sumida, Toshiya Okazue, Kiyoshi Yamada, Yasushi Nagata
Radiochromic films are important tools for assessing complex dose distributions. Gafchromic EBT-XD films have been designed for optimal performance in the 40-4,000 cGy dose range. We investigated the dosimetric characteristics of these films, including their dose-response, postexposure density growth, and dependence on scanner orientation, beam energy, and dose rate with applications to high-dose volumetric-modulated arc therapy (VMAT) verification. A 10 MV beam from a TrueBeam STx linear accelerator was used to irradiate the films with doses in the 0-4,000 cGy range...
November 2016: Journal of Applied Clinical Medical Physics
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