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Gafchromic film

Simon J Woodings, J J Bluemink, J H Wilfred de Vries, Yury Niatsetski, Bob van Veelen, Joost Schillings, Jan G M Kok, Jochem W H Wolthaus, Sara L Hackett, Bram van Asselen, Helena Maria van Zijp, Stefan Pencea, David A Roberts, Jan J W Lagendijk, Bas W Raaymakers
As a prerequisite for clinical treatments it was necessary to characterize the Elekta 1.5 T MRI-linac 7 MV FFF radiation beam. Following acceptance testing, beam characterization data were acquired with Semiflex 3D (PTW 31021), microDiamond (PTW 60019), and Farmer-type (PTW 30013 and IBA FC65-G) detectors in an Elekta 3D scanning water phantom and a PTW 1D water phantom. EBT3 Gafchromic film and ion chamber measurements in a buildup cap were also used. Special consideration was given to scan offsets, detector effective points of measurement and avoiding air gaps...
March 9, 2018: Physics in Medicine and Biology
Hannu Jarvinen, Jad Farah, Teemu Siiskonen, Olivera Ciraj-Bjelac, Jérémie Dabin, Eleftheria Carinou, Joanna Domienik-Andrzejewska, Dariusz Kluszczynski, Željka Knežević, Renata Kopec, Marija Majer, Francoise Malchair, Anna Negri, Piotr Pankowski, Sandra Sarmento, Annalisa Trianni
PURPOSE: The feasibility of setting-up generic, hospital-independent dose alert levels to initiate vigilance on possible skin injuries in interventional procedures was studied for three high-dose procedures (chemoembolization (TACE) of the liver, neuro-embolization (NE) and percutaneous coronary intervention (PCI)) in 9 European countries. METHODS: Gafchromic® films and thermoluminescent dosimeters (TLD) were used to determine the Maximum Skin Dose (MSD). Correlation of the online dose indicators (fluoroscopy time, kerma- or dose-area product (KAP or DAP) and cumulative air kerma at interventional reference point (Ka,r )) with MSD was evaluated and used to establish the alert levels corresponding to a MSD of 2 Gy and 5 Gy...
February 2018: Physica Medica: PM
Yunhe Xie, Christopher Ainsley, Lingshu Yin, Wei Zou, James McDonough, Timothy D Solberg, Alexander Lin, Boon-Keng Kevin Teo
A major source of uncertainty in proton therapy is the conversion of Hounsfield unit (HU) to proton stopping power ratio relative to water (SPR). In this study, we measured and quantified the accuracy of a stoichiometric dual energy CT (DECT) SPR calibration. We applied a stoichiometric DECT calibration method to derive the SPR using CT images acquired sequentially at [Formula: see text] and [Formula: see text]. The dual energy index was derived based on the HUs of the paired spectral images and used to calculate the effective atomic number (Zeff ), relative electron density ([Formula: see text]), and SPRs of phantom and biological materials...
March 7, 2018: Physics in Medicine and Biology
Hosein Azimian, Mahdieh Dayyani, Mohammad Taghi Bahreyni Toossi, Mahmoud Mahmoudi
Objectives: Radiotherapy is one of the most effective modalities of cancer therapy, but clinical responses of individual patients varies considerably. To enhance treatment efficiency it is essential to implement an individual-based treatment. The aim of present study was to identify the mechanism of intrinsic apoptosis pathway on radiosensitivity and normal tissue complications caused by the radiotherapy. Materials and Methods: Peripheral blood mononuclear cells from ten breast cancer patients were exposed to 6MV X-rays to deliver 1 and 2 Gy...
March 2018: Iranian Journal of Basic Medical Sciences
Nada Tomic, Pavlos Papaconstadopoulos, Saad Aldelaijan, Juha Rajala, Jan Seuntjens, Slobodan Devic
PURPOSE: We compare image quality parameters derived from phantom images taken on three commercially available radiotherapy CT simulators. To make an unbiased evaluation, we assured images were obtained with the same surface dose measured using XR-QA2 model GafChromic™ film placed at the imaging phantom surface for all three CT-simulators. METHODS: Radiotherapy CT simulators GE LS 16, Philips Brilliance Big Bore, and Toshiba Aquilion LB were compared in terms of spatial resolution, low contrast detectability, image uniformity, and contrast to noise ratio using CATPHAN-504 phantom, scanned with Head and Pelvis protocols...
January 2018: Physica Medica: PM
Yasuyuki Shimizu, Hiroaki Akasaka, Daisuke Miyawaki, Naritoshi Mukumoto, Masao Nakayama, Tianyuan Wang, Saki Osuga, Sachiko Inubushi, Ryuichi Yada, Yasuo Ejima, Kenji Yoshida, Takeaki Ishihara, Ryohei Sasaki
In cancer research, small animal models, for example, mice, rats, or rabbits, facilitate the in-depth study of biological processes and the effects of radiation treatment that can lead to breakthrough discoveries. However, the physical quality of small animal irradiation systems has not been previously evaluated. In this study, we evaluate the quality of a small animal irradiation system using GAFCHROMIC™ film and a Tough Water Phantom. The profiles and percentage depth dose curves for several irradiation conditions were measured to evaluate the quality of the irradiation system...
January 17, 2018: Kobe Journal of Medical Sciences
Yair Hillman, Josh Kim, Indrin Chetty, Ning Wen
PURPOSE: Mobius 3D (M3D) provides a volumetric dose verification of the treatment planning system's calculated dose using an independent beam model and a collapsed cone convolution superposition algorithm. However, there is a lack of investigation into M3D's accuracy and effectiveness for stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) quality assurance (QA). Here, we collaborated with the vendor to develop a revised M3D beam model for SRS/SBRT cases treated with a 6X Flattening Filter Free (FFF) beam and high definition multiple leaf collimator (HDMLC) on an Edge linear accelerator...
February 12, 2018: Medical Physics
Shunsuke Yonai, Chinatsu Arai, Kaoru Shimoyama, Nathalie Fournier-Bidoz
Radiochromic film is a very useful tool for 2D dosimetric measurements in radiotherapy because it is self-developing and has very high-spatial resolution. However, considerable care has to be taken in ion beam radiotherapy owing to the quenching effect of high-linear energy transfer (LET) radiation. In this study, the dose responses of GAFchromic EBT3 and EBT-XD films were experimentally investigated using the clinical carbon ion beam at the Heavy Ion Medical Accelerator in Chiba. Results showed that the relations between absorbed dose and net optical density could be expressed well using an equation proposed by Reinhardt (2015)...
February 3, 2018: Radiation Protection Dosimetry
von Voigts-Rhetz Philip, Vorwerk Hilke, Zink Klemens
The electron fluence inside a parallel-plate ionization chamber positioned in a water phantom and exposed to a clinical electron beam deviates from the unperturbed fluence in water in absence of the chamber. One reason for the fluence perturbation is the "in-scattering effect" as described in ICRU 35. Aim of this work is a detailed experimental and with Monte Carlo simulations investigation of this effect. The experiments and Monte Carlo Simulations, with EGSnrc [1], were performed in a solid-water phantom (RW3) sized 30 × 30 × 30 cm3...
January 2018: Physica Medica: PM
Kwang-Ho Lee, Ji-Yong Shin, Eun-Hee Kim
Commercial alpha-emitting sources are fabricated mainly in a disc type. An alpha particle irradiator in Radiation Bioengineering Laboratory at Seoul National University was installed with an Am-241 disc source. Commercial Am-241 disc sources are fabricated by incorporating the radioactive element into a thin substrate layer. Those disc sources are utilized assuming that the radioactive element is uniformly distributed in the active layer of disc sources. In this study, we employed peeled-off Gafchromic EBT3 films to investigate the uniformity of areal radioactivity density over the disc source and to measure the effect of non-uniform activity distribution on dose distribution at the bottom of the cell culture dish positioned in a varying distance from the source...
January 31, 2018: Applied Radiation and Isotopes
C Fedon, M Caballo, R Longo, A Trianni, I Sechopoulos
PURPOSE: To investigate the performance, such as energy dependence and sensitivity, of thermoluminescent dosimeters (TLD), metal oxide semiconductor field-effect transistor dosimeters (MOSFET), and GafChromic™ films, and to validate the estimates of local dose deposition of a Monte Carlo (MC) simulation for breast dosimetry applications. METHODS: Experimental measurements were performed using a monoenergetic beam at the ELETTRA synchrotron radiation light source (Trieste, Italy)...
February 6, 2018: Medical Physics
J Greffier, J Goupil, A Larbi, X Stefanovic, F Pereira, G Moliner, S Ovtchinnikoff, J P Beregi, J Frandon
PURPOSE: To assess the value of the routine use of radiochromic films in abdominopelvic embolization procedures to improve patient follow-up. METHODS: A total of 55 patients who underwent transcatheter abdominopelvic embolization were prospectively included. Six types of procedures were evaluated including hepatic chemoembolization (HCE), gonadal veins embolization (GVE), uterine elective embolization (UEE), uterine urgent embolization (UUE), abdominal elective embolization (AEE), and abdominal urgent embolization (AUE)...
January 29, 2018: Diagnostic and Interventional Imaging
Ananda Giri Babu Alagar, Kadirampatti Mani Ganesh, Karunakaran Kaviarasu
Dose calculation for small field radiotherapy with heterogeneity often involves discrepancies, so that algorithms used by treatment planning systems (TPS) should be evaluated with reference to achieving optimal treatment results. Accuracy of two model based algorithms, AcurosXB (AcXB) and the analytical anisotropic algorithm (AAA) from Eclipse TPS, were here tested. Measurements are made using Gafchromic EBT3 films with indigenously generated lung phantoms irradiated with 6 MV photons. Lung phantoms contained two types of tumor plugs, one kept at an interface attached to the chest wall in right lung (RIT) and the other at the centre of the left lung (LCT)...
January 27, 2018: Asian Pacific Journal of Cancer Prevention: APJCP
O A Awunor
PURPOSE: The determination of source positions before treatment is an essential part of the quality assurance (QA) associated with high dose rate brachytherapy treatments. The purpose of this study was to design and commission a tool to allow the quantification of source positions across multiple transfer tube types. METHODS AND MATERIALS: A bespoke flexi-adapter jig, three transfer tube adapters, and a film piercing pointer were designed and built for source position QA across three transfer tube types-the standard, 6 French, and gynae transfer tubes...
January 15, 2018: Brachytherapy
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 (2D) examinations (panoramic and periapical radiographs) and cone beam CT (CBCT). METHODS: Organ doses were determined using an anthropomorphic 10-year-old 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 16, 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) for192 Ir 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...
March 2018: Brachytherapy
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