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Radiochromic film

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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
José Fernando Pérez Azorin, Luis Isaac Ramos Garcia, Diego Maza Ozcoidi, Julio F Almansa
PURPOSE: To analyze the changes in the polarization state of the flatbed scanner light caused by the EBT3 films and to propose a new method for correcting the lateral effects. METHODS AND MATERIALS: The polarization changes induced by radiochromic films are analyzed using linear polarizing film. Based on the results, the linear polarizing films are used in the scanning process of the EBT3 films. This method is tested against the conventional EBT3 dosimetry using a series of simple regular beams and 21 cases of IMRT...
August 2016: Physica Medica: PM
S N Chen, M Gauthier, M Bazalova-Carter, S Bolanos, S Glenzer, R Riquier, G Revet, P Antici, A Morabito, A Propp, M Starodubtsev, J Fuchs
Radiochromic films (RCF) are commonly used in dosimetry for a wide range of radiation sources (electrons, protons, and photons) for medical, industrial, and scientific applications. They are multi-layered, which includes plastic substrate layers and sensitive layers that incorporate a radiation-sensitive dye. Quantitative dose can be retrieved by digitizing the film, provided that a prior calibration exists. Here, to calibrate the newly developed EBT3 and HDv2 RCFs from Gafchromic™, we used the Stanford Medical LINAC to deposit in the films various doses of 10 MeV photons, and by scanning the films using three independent EPSON Precision 2450 scanners, three independent EPSON V750 scanners, and two independent EPSON 11000XL scanners...
July 2016: Review of Scientific Instruments
Takeshi Kamomae, Masataka Oita, Naoki Hayashi, Motoharu Sasaki, Hideki Aoyama, Hiroshi Oguchi, Mariko Kawamura, Hajime Monzen, Yoshiyuki Itoh, Shinji Naganawa
The aim of this study is to investigate the dosimetric uncertainty of stochastic noise and the post-irradiation density growth for reflective-type radiochromic film to obtain the appropriate dose from the exactly controlled film density. Film pieces were irradiated with 6-MV photon beams ranging from 0 to 400cGy. The pixel values (PVs) of these films were obtained using a flatbed scanner at elapsed times of 1min to 120h between the end of irradiation and the film scan. The means and standard deviations (SDs) of the PVs were calculated...
July 26, 2016: Physica Medica: PM
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...
2016: Journal of Applied Clinical Medical Physics
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