Method and Materials. Radiopaque 3D printed patient head and neck phantoms manufactured with potassium iodide doped ink were used for simulation of patient imaging. Two tube voltage settings, six tube current settings, and three pitch settings were systematically combined. Images were reconstructed with filtered back projection (FBP) and iterative reconstruction (IR). Image quality was evaluated with rater experiments (ten radiologist readers) and contrast-to-noise ratios. Dose reduction was evaluated with multiple phantoms with different anatomies and compared with patients that were retrospectively identified from our clinical database. A protocol with fixed 120 kVp, AEC (SD 7.5), a pitch of 0.8, and iterative reconstruction was used as reference to illustrate protocol optimization potential. 54 data sets were acquired and analyzed. Inter-rater reliability of the image grading experiments was excellent (ICC = 0.921; 95%CI 0.882 to 0.950). The benefit-to-risk ratio in terms of achievable image quality and required dose exposure was optimal with ATVS, AEC (SD 14), a pitch of 0.8, and IR. However, image quality was limited (46% for subjective and 26% for objective image quality). An optimal balance between dose and high image quality was achieved with lower noise level AEC (SD 7.5). This protocol required 37% lower dose than the reference protocol. The retrospective analysis of patients that were imaged with different protocol settings yielded similar dose reduction.
Method and Materials. We enrolled a hundred and thirty patients with known oncological diseases; all patients were examined, during their clinical follow- up, with both a low-dose CT performed on 256-row scanner,with 100 kV and automated mAs modulation (depending on patient weight),and a standard-dose CT performed on 256-row scanner, with 120 kV and automated mAs modulation. Images were reconstructed with IMR for the low-dose CT protocols and iDose algorithm for the standard-dose CT studies. In both studies we measured density values and image noise in liver and spleen and we calculated the signal-to-noise ratio(SNR) and the radiation dose exposure. The diagnostic quality evaluation was also performed with a 4-point scale.
Method and Materials. The homogeneous module of the ACR CT phantom (model 464, Gammex-RMI, Wisconsin) was scanned on a GE revolution HD 64- slice CT at 3.6 mGy (CTDI-16 cm). Each scan was repeated twice for NPS calculation. Radiation exposure was increased from 3.6 to 72 mGy to simulate ideal noise reduction without PS or ASir-V. We designed a set of deconvolution filters for the various strengths of ASir-V, followed by PS and name this approach as ASir-VDPS. The images of the ASir-V and ASir-VDPS settings from 10 to 100% and the PS settings of 1 to 9 were compared. Noise magnitude ratio (NMR) was taken between the areas under the NPS curve of the noise reduction and the baseline FBP images to indicate the amount of noise removed by the reconstruction. Smaller NMR means more noise reduction. A desirable noise reduction shall maintain CFR of close to 1 and a NMR of close to 0. When the radiation exposure was increased from 3.6 to 72 mGy, NMR can be reduced without any change of CFR for the ideal noise reduction. At 3.6 mGy, noise reduction was better achieved by either ASir-VDPS or PS, followed by XXxx-X. However, the results of ASir-VDPS (80 to 100%) demonstrated that our current design of deconvolution was not sufficient for resolution recovery introduced by XXxx-X.
Method and Materials. As the objective is to analyze the APA decisions from the point of view of EU State aid rules, doctrinal legal research is the main method used. Doctrinal legal research includes critical analysis of the relevant legislation and case law and using this analysis to treat the research questions.33 In order to find out whether the APA decisions are in line with EU law, there is a need to analyze the legislation concerning State aid. For this purpose, doctrinal legal research and systematizing is needed.34 Although doctrinal legal research is the basis for this dissertation, teleological interpretation is also used. Teleological interpretation plays a part especially when analyzing if State aid rules are fitting to treat measures such as the APA rulings and if it is justified that the APA rulings 32 Xxxxxxx 2014, 220. 33 Xxxxxxxxxx 2014, 584. 34 Hirvonen 2011, 21 and 25; are deemed selective State aid. The objectives behind State Aid rules play a role in this analysis, since the Article 107 TFEU is highly objective-based. The objectives of State Aid rules are, inter alia, to prevent the distortion of competition in the internal market and create a level playing field for undertakings.35 Therefore, “external” economic perspective on EU State aid rules is needed when analyzing the APA rulings in the light of the objectives of State aid rules.36 These objectives are taken into account by the ECJ when assessing State aid cases, and this should play its part when analyzing the APA decisions. The theoretical framework of the dissertation is based on the analysis of academic articles of legal scholars and EU legal sources. To answer the first research question I need to find out what in practice means the wording of Article 107 TFEU, “favouring certain undertakings or the production of certain goods”, and how does it relate to the APA decisions. In order to find out the answer, I will analyze the applicable legal norms concerning the selectivity condition in State aid law and apply the findings to the APA decisions. There is a lot of previous ECJ case law concerning the selectivity condition in general and also in the context of tax benefits. Also when it comes to answering the second research question, the ECJ case law will be largely used. For this purpose, legal analogy is used when applying the ECJ case law when analyzing the APA decisions, since there is not yet ECJ case law directly on individual APA rulings.37 As stated above, the APA decisions have triggered ...
Method and Materials
