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...

The concept mapping methodology aims to respond to the non trivial task of conceptualising abstract thoughts by means of a focus group composed by experts from the studied domain. The approach defines a set of general steps that allow experts to lead the generation of ideas, group the ideas in a conceptual map of interrelated concepts using clustering multidimensional scaling and clustering techniques, analysing the quality of the conceptual maps and deciding on a final interpretation. In this sense, this final decision is not trivial because clustering techniques provide a set of potentially conceptual maps so experts must select the one that fits best according to their opinion. For this reason, we present the global index of consensus as an indicator for filtering the most suitable clustering solutions using qualitative reasoning. It promotes the consensus of experts opinions and ensures objectivity in the final interpretation. The index outperforms three of the most well-known clustering validation indexes in a case study focused on the meaning of excellence in hospitality industry. This work presents the global index of consensus as an indicator for filtering the most suitable clustering solutions using qualitative reasoning that promotes the consensus of experts' opinions, which is one of the key aspects in the concept mapping methodology. The index outperforms three of the most well-known clustering validation indexes in a case study focused on the meaning of excellence in hospitality.

Mass tourism is growing uncontrolled in many destinations worldwide. Negative impacts emerge from it, transforming the city and influencing on locals’ lifestyle and well-being. However, debates and contradictions emerge on the real impact on communities. From that, a deeper analysis of this issue is needed to understand how people perceive tourism and its effects. A quantitative study was conducted in two mature destinations in Spain: Barcelona and Sevilla. One of the major findings from this research is the importance of locals’ support to manage tourism. Practical and managerial implications are suggested in order to promote more sustainable and participative development of destinations.

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