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Purpose/Objective: New definitions for some dosimetric parameters for use in quality assurance of flattening filter free (FFF) beams generated by medical linear accelerators have been suggested. The present study aims to validate these suggestions and to propose possible reference levels. Materials and Methods:The main characteristics of FFF photon beams were described in terms of: field size, penumbra, unflatness, slope and peak-position parameters. Data were collected for 6 and 10 MV-FFF beams from three different Varian TrueBeam linacs, and a Varian Clinac iX upgraded to FFF capability for its 6 MV. Measurements were performed with a 2D-array (Starcheck system from PTW-Freiburg), with a linear array (LA48 system from PTW-Freiburg) and with the portal dosimetry method GLAaS utilizing the build-in portal imager of TrueBeam.Results: All the parameters suggested to characterize the FFF beams were measured and evaluated Little variation was observed among the different linacs. Referring to two reference field sizes of 10x10 and 20x20cm 2 , at SDD=100cm and d=d max , from the portal imaging data converted into dose map with the GLAaS method, the following results were obtained, averaged on X and Y profiles. Field size: 9.95±0.02 cm and 19.98±0.03 cm (including allenergies. Penumbra: 2.7±0.3 mm and 2.9±0.3 mm for 6MV-FFF; 3.1±0.2 mmand 3.3±0.3 for 10MV-FFF. Unflatness: 1.11±0.01 and 1.25±0.01 for 6MV-FFF; 1.21±0.01 and1.50±0.01 for 10MV-FFF. Slope: 0.320±0.020 %/mm and 0.43±0.015 %/mm for 6MV-FFF; 0.657±0.023%/mm and 0.795±0.017 %/mm for 10MV-FFF. Peak Position: -0.2±0.2 mm and -0.4±0.2 mm for 6MV-FFF; -0.3±0.2 mm and 0.7±0.3 mmfor 10MV-FFF. Results would depend upon measurement depth. With thresholds set to at least 95% confidence level from the measured data, and to account for possible variations between detectors and methods and experimental settings, a tolerance set of: 1 mm for field size and penumbra, 0.04 for unflatness, 0.1 %/mm for slope and 1 mm for peak position could be proposed from our data. Conclusions:The parameters proposed to characterize the FFF profiles (in particular the unflatness, the slope and the peak position) appear to be a viable solution for routine checks, also presenting strong similarity to the conventional parameters used for flattened beams. The results from three different TrueBeams and a Clinac-iX suggested the robustness of the methods and the possibility to use general tolerances for the parameters. The data suggested also the reproducibility of beam characteristics among different systems (of the same vendor) and could therefore be possibly generalized.Purpose/Objective: A new method for IMRT verification with EBT3 has been developed, avoiding the need of a previous calibration. Performing a single scan gives the possibility to obtain results in less than one hour and avoids environmental and interscan variability. We have developed a method to evaluate measurements of two-dimensional dose distributions following the protocol described by Lewis et al, without the need of a prev...

Ambient Assisted Living environments provide support to people with disabilities and elderly people, usually at home. This concept can be extended to public spaces, where ubiquitous accessible services allow people with disabilities to access intelligent machines such as information kiosks. One of the key issues in achieving full accessibility is the instantaneous generation of an adapted accessible interface suited to the specific user that requests the service. In this paper we present the method used by the EGOKI interface generator to select the most suitable interaction resources and modalities for each user in the automatic creation of the interface. The validation of the interfaces generated for four different types of users is presented and discussed.