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Introduction: During radiation therapy (RT) treatment, a real-time monitoring of the delivery could increase patients' safety. An independent monitor system was tested to prove the feasibility of real-time monitoring of calibration errors, malfunctions in multi-leaf collimator (MLC) or inappropriate setup parameter during VMAT plan. Material and Methods: 6 months of measures were carried out mounting the iQM® system below the gantry of an Elekta Synergy accelerator. The repeatability of the detector was tested in >70 quality assurance (QA) sessions. A dummy plan (17 segments 4 × 4 cm2 and 1 segment 10 × 10 cm2 with constant 50 MU per segments) and a complex Head and Neck (H&N) VMAT plan (1 arc with 140 control points, low gantry speed, high MU and low dose rate) were used. Sensitivity was tested by introducing specific dosimetric errors of MU (1÷20%) in the H&N plan. Correlation with gantry and collimator angles was evaluated. Results: Delivering the dummy plan in standard condition (gantry and collimator angles = 0°), a counts mean variability of 0.7 ± 1.0% was detected in comparison with the commissioning day. No statistical difference (ANOVA sign. ~1) was detected for all segments in rotational conditions (gantry angle: 0°–90°–180°–270° and collimator angle: 0°–45°–135°–225°–315°). Contrariwise, unexpected counts were observed in the H&N plan with low angle gantry (120° ÷ 240°), showing a mean dose discrepancy of 2.8 ± 1.0% from the original plan. The ad hoc MU introduced errors were detected within a range of [0.1–0.4%] with a linear trend (R2 = 0.99). Conclusion: The repeatability of measures highlights the robustness of the system. Uncorrected rotation of the gantry or increased MU delivered in comparison with the treatment plan was detected. Following the output for each beam segment with the differential and cumulative approach, the detector enables a real-time check during VMAT treatment finalized to patients' safety and to evaluate the daily condition of the machine during QA.

Purpose: Evaluate the feasibility to compare and calculate differences between rival plans, optimized and calculated with Tomotherapy and LINAC. The comparison with Tomotherapy software is not possible at the present. The assessment of multiple plans can help to obtain information regarding dose distribution and allows the selection of the best plan for patients Materials and methods:Treatment plans previously performed by non‐planar fields techniques with LINAC, in patients with prone set‐up have been redeveloped by Tomotherapy planning. The technique is based on the contouring of 2 volumes: PTV and PTVTx. Planned mobile junction is performed at PTVTx. To appreciate differences between the 2 levels of treatment, we have analysed plans performed by Tomotherapy, which allows the delivering of high doses with full sparing of OARs. Results:Data analysis shows that treatments performed by Tomotherapy allow a uniform irradiation not achievable with conventional LINAC. PTV and PTVTx coverage is equal to 100% of the dose required for a volume >95% and dose inhomogeneity does not exceed 105–107% of the prescribed dose. In the case of treatments with LINAC and mobile junction techniques, dose inhomogeneity was between 90–115% at volume of 90–95%. The comparison between the rivals plans demonstrates that gradient and high dose conformation obtained by Tomotherapy, does not allow set‐up mistakes. Tomotherapy allows dose uniformity otherwise not possible with LINAC‐based treatments. On average, for the OARs a saving of 20–30% of the volume is been observed. Conclusions: The results of the quantitative analysis confirms that Cranio‐Spinal irradiation using Tomotherapy is advantages for PTV's coverage, to sparing OARs, for dose uniformity distribution and to decrease the treatment time. Possibility of drawing up rival plans allows comparing and finding the best plan for each patient, based on quantitative data.

The constant growth of the studies on microchannel flows has brought under question the validity of the relations for heat transfer and fluid flow, which are usually employed at the macroscales. Rarefied flows in the slip-flow region have attracted much attention and solutions have been developed using first- and second-order boundary conditions. These models need to be experimentally validated through careful test in order to be able to use them for more complex problems and engineering applications. In the current work the error propagation analysis is applied to a set of error-free measurements artificially generated in order to assess the influence of the uncertainty on each of the measured quantities on the determination of the Poiseuille number for rarefied flows: it is shown that the most limiting factor is the accuracy on the tube diameter, while flowrate and pressure drop errors can be kept contained provided the measurement ranges for the transducers are suitably chosen. The total uncertainty is also calculated and the limit of the investigable Reynolds numbers defined. The possibility of experimentally evidencing the differences between first- and second-order boundary conditions is investigated and it is concluded that this is the case only for highly rarefied flows ( Kn > 0.5).

This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.

In this work the possible use of the μPIV technique for the experimental determination of the microchannel cross-section geometry has been investigated by means of a blind test in which a series of experimental measurements obtained using glass microchannels having a declared rectangular cross-section with a depth of 100 μm and width of 300 μm and a square microchannel with a 300 μm side have been compared with the direct SEM visualisation of the real cross section of the microchannels. For the (oPIV measurements water is used as working fluid. The laminar fully developed 2D velocity profile has been reconstructed by moving the focal plane of the microscope objective from the bottom to the top of the microchannel. The results shown in this paper demonstrate that the real cross section geometry of the microchannel can be predicted by minimizing the difference between the theoretical and the experimental 2D velocity profiles. When the right passage geometry is determined, the average difference between the theoretical and the experimental velocity is within 4-6%.