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Radiochromic film

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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/28436094/dosimetric-validation-of-a-magnetic-resonance-image-gated-radiotherapy-system-using-a-motion-phantom-and-radiochromic-film
#2
James M Lamb, John S Ginn, Dylan P O'Connell, Nzhde Agazaryan, Minsong Cao, David H Thomas, Yingli Yang, Mircea Lazea, Percy Lee, Daniel A Low
PURPOSE: Magnetic resonance image (MRI) guided radiotherapy enables gating directly on the target position. We present an evaluation of an MRI-guided radiotherapy system's gating performance using an MRI-compatible respiratory motion phantom and radiochromic film. Our evaluation is geared toward validation of our institution's clinical gating protocol which involves planning to a target volume formed by expanding 5 mm about the gross tumor volume (GTV) and gating based on a 3 mm window about the GTV...
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
#3
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/28395963/dosimetric-impact-assessment-using-a-general-algorithm-in-geant4-simulations-for-a-complex-shaped-multileaf-collimator
#4
Á Perales, M A Cortés-Giraldo, H Miras, R Arráns, M I Gallardo
PURPOSE: We have developed an inhouse algorithm for the multileaf collimator (MLC) geometry model construction with an appropriate accuracy for dosimetric tests. Our purpose is to build a complex type of MLC and analyze the influence of the modeling parameters on the dose calculation. METHODS: Using radiochromic films as detector the following tests were done: (I) Density test field: to compare measured and calculated dose distributions in order to determine the tungsten alloy physical density value...
April 7, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28361478/commissioning-a-hobby-cutting-device-for-radiochromic-film-preparation
#5
Somayeh Zolfaghari, Kirby E Francis, Tanya Kairn, Scott B Crowe
In addition to a high spatial resolution and well characterised dose response, one of the major advantages of radiochromic film as a dosimeter is that sheets of film can be cut into pieces suitable for use as calibration films, and for in vivo and phantom measurements. The cutting of film is typically done using scissors or a guillotine, and this process can be time-consuming, limited in precision, requires extensive handling and does not allow holes to be cut from the film without cutting from an existing edge...
March 30, 2017: Australasian Physical & Engineering Sciences in Medicine
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
#6
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/28331147/basic-study-on-visibility-and-water-equivalency-of-a-new-colorless-transparent-bolus-for-electron-radiotherapy
#7
Daiki Maruyama, Shinichi Yamazaki, Emi Honda, Eiji Suzuki, Kouji Hommatsu, Ryo Oshiba, Noboru Sato
Boluses used in electron radiotherapy need to have radiation field visibility and water equivalence. In this report, we have examined field visibility and water equivalence of a new colorless transparent bolus. We examined field visibility, water equivalence, and dose profile. Field visibility was evaluated by comparison to conventional bolus. Water equivalence was investigated by a measured fluence scaling factor. The dose profile was measured by using radiochromic film with the bolus and an ionization chamber in water...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28317325/experimental-verification-of-advanced-collapsed-cone-engine-for-use-with-a-multichannel-vaginal-cylinder-applicator
#8
Brie Cawston-Grant, Hali Morrison, Geetha Menon, Ron S Sloboda
Model-based dose calculation algorithms have recently been incorporated into brachytherapy treatment planning systems, and their introduction requires critical evaluation before clinical implementation. Here, we present an experimental evaluation of Oncentra(®) Brachy Advanced Collapsed-cone Engine (ACE) for a multichannel vaginal cylinder (MCVC) applicator using radiochromic film. A uniform dose of 500 cGy was specified to the surface of the MCVC using the TG-43 dose formalism under two conditions: (a) with only the central channel loaded or (b) only the peripheral channels loaded...
March 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297440/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...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297327/small-field-detector-correction-factors-effects-of-the-flattening-filter-for-elekta-and-varian-linear-accelerators
#10
Madelaine K Tyler, Paul Z Y Liu, Christopher Lee, David R McKenzie, Natalka Suchowerska
Flattening filter-free (FFF) beams are becoming the preferred beam type for stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR), as they enable an increase in dose rate and a decrease in treatment time. This work assesses the effects of the flattening filter on small field output factors for 6 MV beams generated by both Elekta and Varian linear accelerators, and determines differences between detector response in flattened (FF) and FFF beams. Relative output factors were measured with a range of detectors (diodes, ionization chambers, radiochromic film, and microDiamond) and referenced to the relative output factors measured with an air core fiber optic dosimeter (FOD), a scintillation dosimeter developed at Chris O'Brien Lifehouse, Sydney...
May 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
#11
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/28296298/performance-evaluation-of-the-ritg148-set-of-tomotherapy-quality-assurance-tools-using-rtqa-2-radiochromic-film
#12
Eric C Lobb
Version 6.3 of the RITG148+ software package offers eight automated analysis routines for quality assurance of the TomoTherapy platform. A performance evaluation of each routine was performed in order to compare RITG148+ results with traditionally accepted analysis techniques and verify that simulated changes in machine parameters are correctly identified by the software. Reference films were exposed according to AAPM TG-148 methodology for each routine and the RITG148+ results were compared with either alternative software analysis techniques or manual analysis techniques in order to assess baseline agreement...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28279321/head-and-neck-radiation-dose-and%C3%A2-radiation-safety-for-interventional%C3%A2-physicians
#13
Kenneth Fetterly, Beth Schueler, Michael Grams, Glenn Sturchio, Malcolm Bell, Rajiv Gulati
OBJECTIVES: The first aim of this study was to assess the magnitude of radiation dose to tissues of the head and neck of physicians performing x-ray-guided interventional procedures. The second aim was to assess protection of tissues of the head offered by select wearable radiation safety devices. BACKGROUND: Radiation dose to tissues of the head and neck is of significant interest to practicing interventional physicians. However, methods to estimate radiation dose are not generally available, and furthermore, some of the available research relating to protection of these tissues is misleading...
March 13, 2017: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/28268058/investigating-the-spatial-accuracy-of-cbct-guided-cranial-radiosurgery-a-phantom-end-to-end-test-study
#14
Juan-Francisco Calvo-Ortega, Marcelino Hermida-López, Sandra Moragues-Femenía, Miquel Pozo-Massó, Joan Casals-Farran
PURPOSE: To evaluate the spatial accuracy of a frameless cone-beam computed tomography (CBCT)-guided cranial radiosurgery (SRS) using an end-to-end (E2E) phantom test methodology. METHODS AND MATERIALS: Five clinical SRS plans were mapped to an acrylic phantom containing a radiochromic film. The resulting phantom-based plans (E2E plans) were delivered four times. The phantom was setup on the treatment table with intentional misalignments, and CBCT-imaging was used to align it prior to E2E plan delivery...
March 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28259503/radiation-exposure-of-patients-and-interventional-radiologists-during-prostatic-artery-embolization-a-prospective-single-operator-study
#15
Gustavo Andrade, Helen J Khoury, William J Garzón, Felipe Dubourcq, Michel F Bredow, Lucas M Monsignore, Daniel G Abud
PURPOSE: To prospectively analyze the radiation exposure of patients and interventional radiologists during prostatic artery embolization (PAE). MATERIALS AND METHODS: Twenty-five consecutive PAE procedures performed with an Artis zee system in a single center by an interventional radiologist were prospectively monitored. The mean age, weight, and prostate volume of the patients were 65.7 year (range, 43-85 y), 71.4 kg (range, 54-88 kg), and 79 cm(3) (range, 36-157 cm(3)), respectively...
March 2, 2017: Journal of Vascular and Interventional Radiology: JVIR
https://www.readbyqxmd.com/read/28240218/an-anthropomorphic-breathing-phantom-of-the-thorax-for-testing-new-motion-mitigation-techniques-for-pencil-beam-scanning-proton-therapy
#16
R L Perrin, M Zakova, M Peroni, K Bernatowicz, C Bikis, A K Knopf, S Safai, P Fernandez-Carmona, N Tscharner, D C Weber, T C Parkel, A J Lomax
Motion-induced range changes and incorrectly placed dose spots strongly affect the quality of pencil-beam-scanned (PBS) proton therapy, especially in thoracic tumour sites, where density changes are large. Thus motion-mitigation techniques are necessary, which must be validated in a realistic patient-like geometry. We report on the development and characterisation of a dynamic, anthropomorphic, thorax phantom that can realistically mimic thoracic motions and anatomical features for verifications of proton and photon 4D treatments...
March 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28196271/dose-distribution-at-the-bragg-peak-dose-measurements-using-ebt-and-rtqa-gafchromic-film-set-at-two-positions-to-the-central-beam-axis
#17
Dorota Maria Borowicz, Julian Malicki, Gennady Mytsin, Konstantin Shipulin
AIM: To evaluate the impact of radiochromic film positioning relative to the central beam axis (CAX) in proton beam therapy. Secondarily, to compare the dosimetric measurements obtained by RTQA and EBT film and to compare these to the doses calculated by the treatment planning system (TPS). METHODS: The EBT and RTQA dosimetric radiochromic films were immersed in a water phantom and irradiated with a proton beam. The films were placed parallel to the CAX and at a 5° angle on the horizontal plane to assess the effect of film inclination on Bragg peak profiles...
February 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/28144120/simplified-method-for-creating-a-density-absorbed-dose-calibration-curve-for-the-low-dose-range-from-gafchromic-ebt3-film
#18
Tatsuhiro Gotanda, Toshizo Katsuda, Rumi Gotanda, Tadao Kuwano, Takuya Akagawa, Nobuyoshi Tanki, Akihiko Tabuchi, Tetsunori Shimono, Yasuyuki Kawaji
Radiochromic film dosimeters have a disadvantage in comparison with an ionization chamber in that the dosimetry process is time-consuming for creating a density-absorbed dose calibration curve. The purpose of this study was the development of a simplified method of creating a density-absorbed dose calibration curve from radiochromic film within a short time. This simplified method was performed using Gafchromic EBT3 film with a low energy dependence and step-shaped Al filter. The simplified method was compared with the standard method...
October 2016: Journal of Medical Physics
https://www.readbyqxmd.com/read/28133748/commissioning-of-the-leksell-gamma-knife-%C3%A2-icon%C3%A2
#19
Michele Zeverino, Maud Jaccard, David Patin, Nick Ryckx, Maud Marguet, Constantin Tuleasca, Luis Schiappacasse, Jean Bourhis, Marc Levivier, Francois O Bochud, Raphaël Moeckli
PURPOSE: The Leksell Gamma Knife (LGK) Icon has been recently introduced to provide Gamma Knife technology with frameless stereotactic treatments which use an additional cone-beam CT (CBCT) imaging system and a motion tracking system (IFMM, Intra-Fraction Motion Management). The system was commissioned for the treatment unit itself as well as the imaging system. METHODS: The LGK Icon was calibrated using an A1SL ionization chamber. EBT3 radiochromic films were employed to independently check the machine calibration, to measure the relative output factors (ROFs) and to collect dose distributions...
February 2017: Medical Physics
https://www.readbyqxmd.com/read/28102953/air-kerma-strength-determination-of-an-hdr-192-ir-source-including-a-geometric-sensitivity-study-of-the-seven-distance-method
#20
Blake R Smith, John A Micka, Manik Aima, Larry A DeWerd, Wesley S Culberson
PURPOSE: To perform an in-air air-kerma strength (SK) calibration of the Bebig model Ir2.A85-2 192Ir high-dose rate (HDR) brachytherapy source manufactured by Mallinckrodt Medical (Westerduinweg, Germany) with the NIST-traceable seven-distance technique established by the University of Wisconsin. A comparison was made between the reference air-kerma rate (RAKR) reported on a certificate from the Physikalisch-Technische Bundesanstalt (Berlin, Germany) (PTB) primary laboratory and the SK determined at the University of Wisconsin Madison Radiation Research Center (UWMRRC)...
January 2017: Medical Physics
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