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Gafchromic film

D Krzempek, G Mianowska, N Bassler, L Stolarczyk, R Kopec, B Sas-Korczynska, P Olko
Gafchromic EBT3 films are applied in proton radiotherapy for 2D dose mapping because they demonstrate spatial resolution well below 1 mm. However, the film response must be corrected in order to reach the accuracy of dose measurements required for the clinical use. The in-house developed AnalyseGafchromic software allows to analyze and correct the measured response using triple channel dose calibration, statistical scan-to-scan fluctuations as well as experimentally determined dose and LET dependence. Finally, the optimized protocol for evaluation of response of Gafchromic EBT3 films was applied to determine 30 × 40 cm2 dose profiles of the scanning therapy unit at the Cyclotron Centre Bronowice, CCB in Krakow, Poland...
January 17, 2018: Radiation Protection Dosimetry
E Spelleken, S B Crowe, B Sutherland, C Challens, T Kairn
Gafchromic EBT3 film is widely used for patient specific quality assurance of complex treatment plans. Film dosimetry techniques commonly involve the use of transmission scanning to produce TIFF files, which are analysed using a non-linear calibration relationship between the dose and red channel net optical density (netOD). Numerous film calibration techniques featured in the literature have not been independently verified or evaluated. A range of previously published film dosimetry techniques were re-evaluated, to identify whether these methods produce better results than the commonly-used non-linear, netOD method...
January 17, 2018: Australasian Physical & Engineering Sciences in Medicine
Grzegorz Zwierzchowski, Grzegorz Bieleda, Janusz Skowronek
Background: Fast and easily repeatable methods for commissioning procedures for brachytherapy (BT) treatment planning systems (TPS) are needed. Radiochromic film dosimetry with gamma analysis is widely used in external beam quality assurance (QA) procedures and planar film dosimetry is also increasingly used for verification of the dose distribution in BT applications. Using the gamma analysis method for comparing calculated and measured dose data could be used for commissioning procedures of the newly developed TG-186 and MBDCA calculation algorithms...
December 2017: Radiology and Oncology
Nils Kadesjö, Randi Lynds, Mats Nilsson, Xie-Qi Shi
OBJECTIVES: To compare the radiation dose to children examined for impacted canines, using two-dimensional examinations (panoramic and periapical radiographs) and cone-beam computed tomography (CBCT). METHODS: Organ doses were determined using an anthropomorphic 10-year child phantom. Two CBCT devices, a ProMax3D and a NewTom5G, were examined using thermoluminescent dosimeters. For the panoramic radiograph, a Promax device was used and for periapical radiographs, a Prostyle device with a ProSensor digital sensor was used...
January 5, 2018: Dento Maxillo Facial Radiology
Somayeh Gholami, Hassan Ali Nedaie, Francesco Longo, Mohammad Reza Ay, Sharifeh A Dini, Ali S Meigooni
Purpose: The clinical efficacy of Grid therapy has been examined by several investigators. In this project, the hole diameter and hole spacing in Grid blocks were examined to determine the optimum parameters that give a therapeutic advantage. Methods: The evaluations were performed using Monte Carlo (MC) simulation and commonly used radiobiological models. The Geant4 MC code was used to simulate the dose distributions for 25 different Grid blocks with different hole diameters and center-to-center spacing...
October 2017: Journal of Medical Physics
Brie Cawston-Grant, Hali Morrison, Ron S Sloboda, Geetha Menon
PURPOSE: To experimentally assess the performance of the Advanced Collapsed-cone Engine (ACE) for 192Ir high-dose-rate brachytherapy treatment planning of nonmelanoma skin cancers of the scalp. METHODS AND MATERIALS: A layered slab phantom was designed to model the head (skin, skull, and brain) and surface treatment mold using tissue equivalent materials. Six variations of the phantom were created by varying skin thickness, skull thickness, and size of air gap between the mold and skin...
November 24, 2017: Brachytherapy
Teerth Raj Verma, Nirmal K Painuly, Surendra P Mishra, Navin Singh, M L B Bhatt, Naseem Jamal, M C Pant
AIM: To evaluate dose calculation accuracy of various algorithms in lung equivalent inhomogeneity comprising tumor within it and comparison with Gafchromic film data. MATERIALS AND METHODS: Gafchromic film measured central axis absorbed dose in lung insert (-700 Hounsfield unit [HU]), in racemosa wood cylindrical inhomogeneity (-725 HU) and at three surfaces of tumor (-20 HU) created in cylindrical inhomogeneity, put in the cavity of computerized imaging reference systems (CIRS) thorax phantom were compared with convolution (CON), superposition (SP), fast SP (FSP), and X-ray voxel Monte Carlo (XVMC) algorithms calculated dose using 6 MV beams of field size 2 cm × 2 cm, 3 cm × 3 cm, 4 cm × 4 cm, 5 cm × 5 cm, and 8 cm × 8 cm...
October 2017: Journal of Cancer Research and Therapeutics
Maud Jaccard, Maria Teresa Durán, Kristoffer Petersson, Jean-François Germond, Philippe Liger, Marie-Catherine Vozenin, Jean Bourhis, François Bochud, Claude Bailat
PURPOSE: The Oriatron eRT6 is an experimental high dose-per-pulse linear accelerator (linac) which was designed to deliver an electron beam with variable dose-rates, ranging from a few Gy/min up to hundreds of Gy/s. It was built to study the radiobiological effects of high dose-per-pulse/dose-rate electron beam irradiation, in the context of preclinical and cognitive studies. In this work, we report on the commissioning and beam monitoring of the Oriatron eRT6 prototype linac. MATERIALS AND METHODS: The beam was characterized in different steps...
December 5, 2017: Medical Physics
Silvia Calusi, Linhsia Noferini, Livia Marrazzo, Marta Casati, Chiara Arilli, Antonella Compagnucci, Cinzia Talamonti, Silvia Scoccianti, Daniela Greto, Lorenzo Bordi, Lorenzo Livi, Stefania Pallotta
PURPOSE: We present the γTools, a new phantom designed to assess geometric and dosimetric accuracy in Gamma Knife treatments, together with first tests and results of applications. METHODS: The phantom is composed of two modules: the imaging module, a regular grid of 1660 control points to evaluate image distortions and image registration result and the dosimetry module for delivered dose distribution measurements. The phantom is accompanied by a MatLab routine for image distortions quantification...
November 2017: Physica Medica: PM
Nicholas Ade, F C P du Plessis
PURPOSE: To investigate the degree of 18 and 22MeV electron beam dose perturbations caused by unilateral hip titanium (Ti) prosthesis. METHODS: Measurements were acquired using Gafchromic EBT2 film in a novel pelvic phantom made out of Nylon-12 slices in which a Ti-prosthesis is embedded. Dose perturbations were measured and compared using depth doses for 8×8, 10×10 and 11×11cm2 applicator-defined field sizes at 95cm source-surface-distance (SSD). Comparisons were also made between film data at 100cm SSD for a 10×10cm2 field and dose calculations made on CMS XiO treatment planning system utilizing the pencil beam algorithm...
October 2017: Physica Medica: PM
W L Jong, N M Ung, Ath Vannyat, A B Rosenfeld, J H D Wong
Challenges in treating lung tumours are related to the respiratory-induced tumour motion and the accuracy of dose calculation in charged particle disequilibrium condition. The dosimetric characteristics near the interface of lung and Perspex media in a moving phantom during respiratory-gated and non-gated radiotherapy were investigated using Gafchromic EBT2 and the MOSkin detector. The MOSkin detectors showed good agreement with the EBT2 films during static and gated radiotherapy. In static radiotherapy, the penumbral widths were found to be 3...
October 2017: Physica Medica: PM
Saad Aldelaijan, Nada Tomic, Pavlos Papaconstadopoulos, James Schneider, Jan Seuntjens, Shelley Shih, David Lewis, Slobodan Devic
PURPOSE: To evaluate the response of the newest XR-QA2 GafChromic(™) film model in terms of post-exposure signal growth and energy response in comparison with the older XR-QA (Version 2) model. METHODS: Pieces of film were irradiated to air kerma in air values up to 12 cGy with several beam qualities (5.3-8.25 mm Al) commonly used for CT scanning. Film response was scored in terms of net reflectance from scanned film images at various points in time post-irradiation ranging from 1 to 7 days and 5 months post exposure...
November 22, 2017: Medical Physics
Cliff G Hammer, Benjamin Saul Rosen, Jessica M Fagerstrom, Wesley S Culberson, Larry A DeWerd
PURPOSE: To determine experimentally the intrinsic energy response, kbq , of EBT3 GafChromic(®) radiochromic film with kilovoltage x-rays,(137) Cs, and (60) Co in therapeutic and diagnostic dose ranges through direct measurement with an accompanying mathematical approach to describe the physical processes involved. METHODS: EBT3 film was irradiated to known doses using (60) Co, (137) Cs, and 13 NIST-matched kilovoltage x-ray beams. Seven dose levels, ranging from 57 to 7002 mGy, were chosen for this work...
November 21, 2017: Medical Physics
Sarah J Alnaghy, Jarrad Begg, Trent Causer, Thahabah Alharthi, Laura Glaubes, Bin Dong, Armia George, Lois Holloway, Peter Metcalfe
PURPOSE: Longitudinal magnetic fields narrow beam penumbra and tighten lateral spread of secondary electrons in air cavities, including lung tissue. Gafchromic® EBT3 film was used to investigate differences between penumbra in solid water and solid lung, without a magnetic field (0 T) and with two field strengths (0.9 and 1.5 T). METHODS: The first prototype of the Australian MRI-linac consisted of a 1.5 T Siemens Sonata MRI and Varian industrial linatron (nominal 4 MV)...
November 20, 2017: Medical Physics
Tomohiro Ono, Yuki Miyabe, Kunio Takahashi, Mami Akimoto, Nobutaka Mukumoto, Yoshitomo Ishihara, Mitsuhiro Nakamura, Takashi Mizowaki, Masahiro Hiraoka
PURPOSE: The aim was to examine the feasibility of a dynamic tumor-tracking volumetric modulated arc therapy (DTT-VMAT) technique using a gimbal-mounted linac and assess its positional, mechanical and dosimetric accuracy. MATERIALS AND METHODS: DTT-VMAT was performed using a surrogated signal-based technique. The positional tracking accuracy was evaluated as the difference between the predicted and detected target positions for various wave patterns. Mechanical accuracy measurements included gantry, multileaf collimator (MLC) and gimbal positions...
November 11, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Hayley Wooding, Jing Yan, Ling Yuan, Te-Yu Chyou, Shanbao Gao, Iain Ward, Patries M Herst
OBJECTIVE: Mepitel Film significantly decreases acute radiation-induced skin reactions in breast cancer patients. Here we investigated the feasibility of using Mepitel Film in head and neck cancer patients (ACTRN12614000932662). METHODS: Out of a total of 36 head and neck cancer patients from New Zealand (NZ) (n=24) and China (n=12) recruited between June 2015 and December 2016, 33 patients complied with protocol. Of these, 11 NZ patients followed a management protocol; 11 NZ patients and 11 Chinese patients followed a prophylactic protocol...
October 26, 2017: British Journal of Radiology
Crijns Wouter, Vandenbroucke Dirk, Leblans Paul, Depuydt Tom
Optical stimulated luminescence (OSL) combines reusability, sub-mm resolution, and a linear dose response in a single radiation detection technology. Such a combination is currently lacking in radiotherapy dosimetry. But OSL-films have a strong energy dependent response to keV photons due to a relative high effective atomic number (Z eff). The current work studied the applicability of a 2D OSL-film with a reduced Z eff as (IMRT/VMAT) dosimeter. Based on their commercial OSL-film experience, Agfa Healthcare N...
October 19, 2017: Physics in Medicine and Biology
Somayeh Gholami, Francesco Longo, Hassan Ali Nedaie, Alessio Berti, Mehdi Mousavi, Ali S Meigooni
The Geant4 toolkit was used to develop a Monte Carlo (MC)-based engine for accurate dose calculations in small radiation field sizes. The Geant4 toolkit (version 10.1.p02) was used to simulate 6-MV photon beam of a Varian2100C linear accelerator that is being used for stereotactic radiosurgery (SRS) treatment with small radiation fields. Geometric models of 3 in-house designed radiosurgical divergent cones, with the diameters of their projections at the isocenter being 10, 20, and 30 mm, were simulated. The accuracy of the MC simulation technique was examined by reproducing several different simulated dosimetric parameters of the primary beams with the experimental data...
October 4, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Bradley M Oborn, Maegan A Gargett, Trent J Causer, Sarah J Alnaghy, Nicholas Hardcastle, Peter E Metcalfe, Paul J Keall
BACKGROUND AND PURPOSE: To present experimental evidence of lung dose enhancement effects caused by strong inline magnetic fields. MATERIALS AND METHODS: A permanent magnet device was utilised to generate 0.95T-1.2T magnetic fields that encompassed two small lung-equivalent phantoms of density 0.3g/cm(3). Small 6MV and 10MV photon beams were incident parallel with the magnetic field direction and Gafchromic EBT3 film was placed inside the lung phantoms, perpendicular to the beam (experiment 1) and parallel to the beam (experiment 2)...
October 3, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Nobuteru Nariyama
PURPOSE: Scanning of dosimeters facilitates dose distribution measurements with fine spatial resolutions. This paper presents a method of conversion of the scanning results to water-dose profiles and provides an experimental verification. METHODS: An Advanced Markus chamber and a diamond detector were scanned at a resolution of 6 μm near the beam edges during irradiation with a 25-μm-wide white narrow x-ray beam from a synchrotron radiation source. For comparison, GafChromic films HD-810 and HD-V2 were also irradiated...
September 22, 2017: Medical Physics
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