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Gafchromic film

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https://www.readbyqxmd.com/read/27909929/signal-to-noise-ratio-and-dose-to-the-lens-of-the-eye-for-computed-tomography-examination-of-the-brain-using-an-automatic-tube-current-modulation-system
#1
Supawitoo Sookpeng, Chitsanupong Butdee
PURPOSE: The study aimed to evaluate the image quality in terms of signal-to-noise ratio (SNR) and dose to the lens of the eye and the other nearby organs from the CT brain scan using an automatic tube current modulation (ATCM) system with or without CT gantry tilt is needed. METHODS: An anthropomorphic phantom was scanned with different settings including use of different ATCM, fixed tube current time product (mAs) settings and degree angles of gantry tilt. Gafchromic film XR-QA2 was used to measure absorbed dose of the organs...
December 2, 2016: Emergency Radiology
https://www.readbyqxmd.com/read/27908161/technical-note-magnetic-field-effects-on-gafchromic-film-response-in-mr-igrt
#2
Francisco J Reynoso, Austen Curcuru, Olga Green, Sasa Mutic, Indra J Das, Lakshmi Santanam
PURPOSE: Magnetokinetic changes may affect crystal orientation and polymerization within the active layer of radiochromic film (RCF). This effect is investigated in a magnetic resonance image-guided radiotherapy unit within the context of film dosimetry. METHODS: Gafchromic EBT2 RCF was irradiated in a 30 × 30 × 30 cm(3) solid water phantom using a Co-60 MRI guided radiotherapy system (B = 0.35 T) under normal operating conditions, and under the exact conditions and setup without a magnetic field...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908156/development-of-a-four-axis-moving-phantom-for-patient-specific-qa-of-surrogate-signal-based-tracking-imrt
#3
Nobutaka Mukumoto, Mitsuhiro Nakamura, Masahiro Yamada, Kunio Takahashi, Mami Akimoto, Yuki Miyabe, Kenji Yokota, Shuji Kaneko, Akira Nakamura, Satoshi Itasaka, Yukinori Matsuo, Takashi Mizowaki, Masaki Kokubo, Masahiro Hiraoka
PURPOSE: The purposes of this study were two-fold: first, to develop a four-axis moving phantom for patient-specific quality assurance (QA) in surrogate signal-based dynamic tumor-tracking intensity-modulated radiotherapy (DTT-IMRT), and second, to evaluate the accuracy of the moving phantom and perform patient-specific dosimetric QA of the surrogate signal-based DTT-IMRT. METHODS: The four-axis moving phantom comprised three orthogonal linear actuators for target motion and a fourth one for surrogate motion...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27842981/effect-of-verification-imaging-on-in-vivo-dosimetry-results-using-gafchromic-ebt3-film
#4
Trent Aland, Rebecca Moylan, Tanya Kairn, Jamie Trapp
In this work, the apparent treatment dose that kV planar or CBCT imaging contributes to Gafchromic EBT3 film used for in vivo dosimetry, was investigated. Gafchromic EBT3 film pieces were attached to a variety of phantoms and irradiated using the linear accelerator's built-in kV imaging system, in both kV planar mode and CBCT mode. To evaluate the sensitivity of the film in the clinical scenario where dose contributions are received from both imaging and treatment, additional pieces of film were irradiated using base doses of 50cGy and then irradiated using selected kV planar and CBCT techniques...
November 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27806597/influence-of-standard-rf-coil-materials-on-surface-and-buildup-dose-from-a-6-mv-photon-beam-in-magnetic-field
#5
A Ghila, B G Fallone, S Rathee
PURPOSE: Magnetic resonance guided teletherapy systems aspire to image the patient concurrently with the radiation delivery. Thus, the radiofrequency (RF) coils used for magnetic resonance imaging, placed on or close to patient skin and in close proximity to the treatment volume, would be irradiated leading to modifications of radiation dose to the skin and in the buildup region. The purpose of this work is to measure and assess these dose modifications due to standard off-the-shelf RF coil materials...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27782733/technical-note-calibrating-radiochromic-film-in-beams-of-uncertain-quality
#6
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/27756536/in-phantom-assessment-of-superficial-doses-under-tomotherapy-irradiation
#7
Margherita Zani, Cinzia Talamonti, Marta Bucciolini, Marco Marinelli, Gianluca Verona-Rinati, Pierluigi Bonomo, Fabiola Paiar, Stefania Pallotta
PURPOSE: Aim of this work is the assessment of build-up and superficial doses of different clinical Head&Neck plans delivered with Helical TomoTherapy (HT) (Accuray, Sunnyvale, CA). Depth dose profiles and superficial dose points were measured in order to evaluate the Treatment Planning System (TPS) capability of an accurate dose modeling in regions of disequilibrium. Geometries and scattering conditions were investigated, similar to the ones generally encountered in clinical treatments...
October 15, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27744352/patient-dosimetry-during-interventional-cardiac-procedures-in-a-dedicated-catheterization-laboratory
#8
Satish C Uniyal, Vineet Chaturvedi, Sunil D Sharma, Anurag Rawat
Cardiac interventions often result in high radiation dose to patient's skin, so a reliable indicator in terms of a commonly used dose descriptor is required to monitor skin exposures. In the present study, Gafchromic XR-RV3 film was used to measure the peak skin dose (PSD) during 40 coronary angiography (CA) and 50 percutaneous transluminal coronary angioplasty (PTCA) procedures. Corresponding values of kerma-area product (PKA), fluoroscopy time (FT) and reference air-kerma (Ka,r) were recorded and correlated with PSD...
October 15, 2016: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/27730458/novel-application-of-3d-printing-in-brachytherapy-using-med610-3d-printed-insert-for-i-125-ropes-eye-plaque
#9
L Sim
The purpose of this study was to evaluate if MED610 3D printed material can be used as a surrogate for acrylic in the manufacturing of a replacement insert used in an eye plaque brachytherapy applicator. Measurement of the dose distributions from a standard acrylic insert were compared with dose obtained from MED610 3D printed replica using GafChromic(®) EBT3 films. The study used a 15 mm Radiation Oncology Physics and Engineering Services, Australia (ROPES) type eye plaque applicator loaded with I-125 (model 6711) seeds...
October 11, 2016: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/27720205/a-novel-conformal-superficial-high-dose-rate-brachytherapy-device-for-the-treatment-of-nonmelanoma-skin-cancer-and-keloids
#10
Clara Ferreira, Daniel Johnson, Karl Rasmussen, Clinton Leinweber, Salahuddin Ahmad, Jae Won Jung
PURPOSE: To develop a novel conformal superficial brachytherapy (CSBT) device as a treatment option for the patient-specific radiation therapy of conditions including superficial lesions, postsurgical positive margins, Dupuytren's contractures, keloid scars, and complex anatomic sites (eyelids, nose, ears, etc.). METHODS AND MATERIALS: A preliminary CSBT device prototype was designed, built, and tested using readily available radioactive seeds. Iodine-125 ((125)I) seeds were independently guided to the treatment surface to conform to the target...
October 3, 2016: Brachytherapy
https://www.readbyqxmd.com/read/27716632/characterization-of-al2o3-optically-stimulated-luminescence-films-for-2d-dosimetry-using-a-6-mv-photon-beam
#11
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/27716323/precise-film-dosimetry-for-stereotactic-radiosurgery-and-stereotactic-body-radiotherapy-quality-assurance-using-gafchromic%C3%A2-ebt3-films
#12
Ning Wen, Siming Lu, Jinkoo Kim, Yujiao Qin, Yimei Huang, Bo Zhao, Chang Liu, Indrin J Chetty
PURPOSE: The purpose of this study is to evaluate the dosimetric uncertainty associated with Gafchromic™ (EBT3) films and establish a practical and efficient film dosimetry protocol for Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT). METHOD AND MATERIALS: EBT3 films were irradiated at each of seven different dose levels between 1 and 15 Gy with open fields and standard deviations of dose maps were calculated at each color channel for evaluation...
October 4, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27685135/characterization-of-a-2-5-mv-inline-portal-imaging-beam
#13
James L Grafe, 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...
2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27648087/film-based-verification-of-calculation-algorithms-used-for-brachytherapy-planning-getting-ready-for-upcoming-challenges-of-mbdca
#14
Grzegorz Zwierzchowski, Grzegorz Bielęda, Janusz Skowronek, Magdalena Mazur
PURPOSE: Well-known defect of TG-43 based algorithms used in brachytherapy is a lack of information about interaction cross-sections, which are determined not only by electron density but also by atomic number. TG-186 recommendations with using of MBDCA (model-based dose calculation algorithm), accurate tissues segmentation, and the structure's elemental composition continue to create difficulties in brachytherapy dosimetry. For the clinical use of new algorithms, it is necessary to introduce reliable and repeatable methods of treatment planning systems (TPS) verification...
August 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/27642727/monte-carlo-based-investigations-of-electron-contamination-from-telecobalt-unit-head-in-build-up-region-and-its-impact-on-surface-dose
#15
A S Jagtap, T Palani Selvam, B J Patil, S T Chavan, S N Pethe, Gauri Kulkarni, S S Dahiwale, V N Bhoraskar, S D Dhole
A Telecobalt unit has wide range of applications in cancer treatments and is used widely in many countries all around the world. Estimation of surface dose in Cobalt-60 teletherapy machine becomes important since clinically useful photon beam consist of contaminated electrons during the patient treatment. EGSnrc along with the BEAMnrc user code was used to model the Theratron 780E telecobalt unit. Central axis depth dose profiles including surface doses have been estimated for the field sizes of 0×0, 6×6, 10×10, 15×15, 20×20, 25×25, 30×30cm(2) and at Source-to-surface distance (SSD) of 60 and 80cm...
September 12, 2016: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/27628942/an-open-source-solution-for-an-in-house-built-dynamic-platform-for-the-validation-of-stereotactic-ablative-body-radiotherapy-for-vmat-and-imrt
#16
Luis Munoz, Amy Ziebell, Jason Morton, Madhava Bhat
An in-house solution for the verification of dose delivered to a moving phantom as required for the clinical implementation of lung stereotactic ablative body radiation therapy was developed. The superior-inferior movement required to simulate tumour motion during a normal breathing cycle was achieved via the novel use of an Arduino Uno™, a low-cost open-source microcontroller board connected to a high torque servo motor. Slow CT imaging was used to acquire the image set and a 4D cone beam CT (4D-CBCT) verified the efficacy of contoured margins before treatment on the moving phantom...
September 15, 2016: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/27623695/heterogeneity-and-scatter-effects-on-ir-192-brachytherapy-dose-distribution
#17
Alexander F I Osman, Nabil Maalej, Khateeb Ul-Rahman, Wamied Abdel Rahman
We studied the effects of the presence of an air cavity and scatter due to patient size on dose distribution near an Iriduim-192 brachytherapy source (Ir-192). The source was modeled using Monte Carlo (MC) code MCNP5. The Radial dose, gL(r), and the anisotropy function, F(r,θ) specified by the AAPM TG-43 have been determined and compared with the consensus data (AAPM report No. 229). We compared our MC results to the measured dose distribution using an EBT3 Gafchromic® film measurement. The dose was determined in the presence of an air cavity of 3, 5, and 7mm diameters located at 2mm distance from Ir-192...
September 10, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27592531/3d-printed-applicators-for-high-dose-rate-brachytherapy-dosimetric-assessment-at-different-infill-percentage
#18
Rosalinda Ricotti, Andrea Vavassori, Alessia Bazani, Delia Ciardo, Floriana Pansini, Ruggero Spoto, Vittorio Sammarco, Federica Cattani, Guido Baroni, Roberto Orecchia, Barbara Alicja Jereczek-Fossa
PURPOSE: Dosimetric assessment of high dose rate (HDR) brachytherapy applicators, printed in 3D with acrylonitrile butadiene styrene (ABS) at different infill percentage. MATERIALS AND METHODS: A low-cost, desktop, 3D printer (Hamlet 3DX100, Hamlet, Dublin, IE) was used for manufacturing simple HDR applicators, reproducing typical geometries in brachytherapy: cylindrical (common in vaginal treatment) and flat configurations (generally used to treat superficial lesions)...
September 1, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27587049/technical-note-experimental-results-from-a-prototype-high-field-inline-mri-linac
#19
G P Liney, B Dong, J Begg, P Vial, K Zhang, F Lee, A Walker, R Rai, T Causer, S J Alnaghy, B M Oborn, L Holloway, P Metcalfe, M Barton, S Crozier, P Keall
PURPOSE: The pursuit of real-time image guided radiotherapy using optimal tissue contrast has seen the development of several hybrid magnetic resonance imaging (MRI)-treatment systems, high field and low field, and inline and perpendicular configurations. As part of a new MRI-linac program, an MRI scanner was integrated with a linear accelerator to enable investigations of a coupled inline MRI-linac system. This work describes results from a prototype experimental system to demonstrate the feasibility of a high field inline MR-linac...
September 2016: Medical Physics
https://www.readbyqxmd.com/read/27522056/assessment-of-patient-s-peak-skin-dose-using-gafchromic-films-during-interventional-cardiology-procedures-routine-experience-feedback
#20
J Greffier, G Moliner, F Pereira, L Cornillet, B Ledermann, L Schmutz, M Lomma, G Cayla, J P Beregi
To assess the interest of Gafchromic films in detection of patient's peak skin dose (PSD) in interventional cardiology. A prospective study of 112 patients was conducted (July-December 2015). Three diagnostic and therapeutic procedures were evaluated: coronary angiography (CA), coronary angiography and coronary angioplasty for one or two vessels disease (CA-PTCA) and coronary angioplasty of complex chronic total occlusion (CTO). Dosimetric indicators (DIs) were collected and PSD were measured with Gafchromic films...
August 13, 2016: Radiation Protection Dosimetry
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