keyword
MENU ▼
Read by QxMD icon Read
search

Gafchromic film

keyword
https://www.readbyqxmd.com/read/28436134/measurement-of-skin-surface-dose-distributions-in-radiation-therapy-using-poly-vinyl-alcohol-cryogel-dosimeters
#1
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
#2
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
#3
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
#4
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-sup-192-sup-ir-hdr-brachytherapy-treatment-planning
#5
Eleftherios Pappas, Emmanouil Zoros, Argyris Moutsatsos, Vassiliki 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 <sup>192</sup>Ir brachytherapy treatment planning systems (TPSs), and this work investigates whether it can be met. A PMMA phantom was prepared to accommodate material inhomogeneities (air and Teflon), 4 plastic brachytherapy catheters, as well as 84 LiF TLD dosimeters (MTS-100M 1x1x1 mm<sup>3</sup> microcubes), 2 radiochromic films (Gafchromic EBT3) and a plastic 3D dosimeter (PRESAGE)...
March 29, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28338819/unlaminated-gafchromic-ebt3-film-for-ultraviolet-radiation-monitoring
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
https://www.readbyqxmd.com/read/28297286/the-dose-penumbra-of-a-custom-made-shield-used-in-hemibody-skin-electron-irradiation
#16
Charlotte I Rivers, Ismail AlDahlawi, Iris Z Wang, Anurag K Singh, Matthew B Podgorsak
We report our technique for hemibody skin electron irradiation with a custom-made plywood shield. The technique is similar to our clinical total skin electron irradiation (TSEI), performed with a six-pair dual field (Stanford technique) at an extended source-to-skin distance (SSD) of 377 cm, with the addition of a plywood shield placed at 50 cm from the patient. The shield is made of three layers of standard 5/8" thick plywood (total thickness of 4.75 cm) that are clamped securely on an adjustable-height stand...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297285/deriving-detector-specific-correction-factors-for-rectangular-small-fields-using-a-scintillator-detector
#17
Yujiao Qin, Hualiang Zhong, Ning Wen, Karen Snyder, Yimei Huang, Indrin J Chetty
The goal of this study was to investigate small field output factors (OFs) for flattening filter-free (FFF) beams on a dedicated stereotactic linear accelerator-based system. From this data, the collimator exchange effect was quantified, and detector-specific correction factors were generated. Output factors for 16 jaw-collimated small fields (from 0.5 to 2 cm) were measured using five different detectors including an ion chamber (CC01), a stereotactic field diode (SFD), a diode detector (Edge), Gafchromic film (EBT3), and a plastic scintillator detector (PSD, W1)...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296313/determination-of-mlc-model-parameters-for-monaco-using-commercial-diode-arrays
#18
Paul Kinsella, Laura Shields, Patrick McCavana, Brendan McClean, Brian Langan
Multileaf collimators (MLCs) need to be characterized accurately in treatment planning systems to facilitate accurate intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). The aim of this study was to examine the use of MapCHECK 2 and ArcCHECK diode arrays for optimizing MLC parameters in Monaco X-ray voxel Monte Carlo (XVMC) dose calculation algorithm. A series of radiation test beams designed to evaluate MLC model parameters were delivered to MapCHECK 2, ArcCHECK, and EBT3 Gafchromic film for comparison...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28273357/energy-and-field-size-dependence-of-a-silicon-diode-designed-for-small-field-dosimetry
#19
Mehran Yarahmadi, Sonja Wegener, Otto A Sauer
PURPOSE: To investigate the energy dependence/spectral sensitivity of silicon diodes designed for small-field dosimetry and obtain response factors (RFs) for arbitrary photon spectra using Monte Carlo (MC) simulations. METHODS: The EGSnrc user-code DOSRZnrc was used to calculate the dose deposition in water and in the active volume of a stereotactic diode field detector (SFD). Then the RFs of the SFD were calculated for several circular field sizes and energies at 5 cm depth in water...
March 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28212708/development-and-performance-evaluation-of-a-three-dimensional-clinostat-synchronized-heavy-ion-irradiation-system
#20
Hiroko Ikeda, Hikaru Souda, Anggraeini Puspitasari, Kathryn D Held, Jun Hidema, Takeshi Nikawa, Yukari Yoshida, Tatsuaki Kanai, Akihisa Takahashi
Outer space is an environment characterized by microgravity and space radiation, including high-energy charged particles. Astronauts are constantly exposed to both microgravity and radiation during long-term stays in space. However, many aspects of the biological effects of combined microgravity and space radiation remain unclear. We developed a new three-dimensional (3D) clinostat synchronized heavy-ion irradiation system for use in ground-based studies of the combined exposures. Our new system uses a particle accelerator and a respiratory gating system from heavy-ion radiotherapy to irradiate samples being rotated in the 3D clinostat with carbon-ion beams only when the samples are in the horizontal position...
February 2017: Life Sciences in Space Research
keyword
keyword
66186
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"