In this study, we used the Monte Carlo-based software, GATE, to model the Spot scanning proton therapy system (SIEMENS IONTRIS Spot scanning dedicated nozzle) installed at the Shanghai Proton and Heavy Ion facility. Within the nozzle, apart from entrance and exit windows and the two ion chambers, the beam traverses through the vacuum, allowing for a convergent beam downstream of the nozzle exit. We model the angular, spatial, and energy distributions of the beam phase space at the nozzle exit with single Gaussians, controlled by eight energy-dependent parameters. The parameters were determined from measured profiles and depth dose distributions. Verification of the beam model was done by comparing measured data and GATE acquired relative dose distributions, using plan specific log files from the machine to specify beam Spot positions and energy. The MC simulations showed good agreement with measurements for the depth-dose curve and SOBP plans. The absolute comparison of the absorbed dose difference between the MC and the measurement was ±, 1%. This work describes a method for adapting a MC simulation model for a Spot scanning proton delivery system. The excellent agreement between the measurements and simulations shows that the MC modeling in this work is a precise and reputable method.

Collision of protons with background gas and beamline wall in proton therapy causes the creation of secondary particles, e. g. neutrons, which results in more difficulties in curing the tumors. In the present simulation-based study, the optimum diameter of proton beamline was determined to minimize the production of secondary particles in the presence of electric field with the magnitude of 50 kV/m, perpendicular equal magnetic fields of 0. 7 T, and background gas of argon under Bounce boundary conditions via finite element method. The results showed that the optimum diameter of the beamline for minimization of the secondary particles in the Spot scanning proton therapy in the aforementioned conditions was 7 mm. Also, the values of drift velocities of protons were plotted in different time steps of 10 ns to 50 ns for the optimized size of the beamline. Due to few interactions of forwarding particles with background gas, the results showed that the forwarding particles in the propagation direction have greater velocities than those of rear particles. The results can be used in Spot scanning proton therapy for curing the localized cancers.

The Spot-scan based methods are expected to perform better than other methods for proton therapy in delivering the dose to the intended target. In this study, the GATE computer code is used to evaluate important dosimetric quantities in proton therapy, such as Full width at half maximum, peak position, range and peak-to-entrance dose ratio (percentage depth dose) in the proton therapy process under the same conditions based on Spot scanning and passive scattering. Water phantom was selected and system energy parameters were measured using a set of depth-dose curve in the energy range of 120 to 235 MeV. Bragg peaks were generated with an accuracy of 0. 7 mm in range. Spread out Bragg-peak were produced with 7 cm modulation and 10 mm range accuracy and peak-to-entrance dose ratio difference at an input dose of 8%. To evaluate the versatility of the beam, the Full width at half-maximum was evaluated with a maximum difference of 7% between the two methods. As a result, based on the simulations performed for different beam delivery systems, the ability of the Spot scanning method in adapting to the target volume, better control over dose distribution and less extra-tumor dose was demonstrated.

Confocal microscopy is an established light microscopical technique for imaging fluorescently labeled specimens with significant three-dimensional structure. Laser scanning confocal microscopy has become an invaluable tool for a wide range of investigations in the biological and medical sciences for imaging thin optical sections in living and fixed specimens ranging in thickness up to 100 micrometers. Modern instruments are equipped with 3-5 laser systems controlled by high-speed filters, which allow very precise regulation of wavelength and excitation intensity. Coupled with photomultipliers that have high quantum efficiency in the near-ultraviolet, visible and near-infrared spectral regions, these microscopes are capable of examining fluorescence emission ranging from 400 to 750 nanometers. Instruments equipped with spectral imaging detection systems further refine the technique by enabling the examination and resolution of fluorophores with overlapping spectra as well as providing the ability to compensate for autofluorescence. Recent advances in fluorophore design have led to improved synthetic and naturally occurring molecular probes, including fluorescent proteins and quantum dots, which exhibit a high level of photostability and target specificity.

Examining housing quality issues, among other things, is one of the key issues in housing planning. Housing is a physical place that is considered as a shelter and basic need of the family. The quantity and quality of housing reflects the socio-economic status of the city and many realities of society. Housing is an integrated part of the development of the national economy. Addressing housing indicators as the main planning tool can be considered as one of the most sensitive stages of planning. In order to ensure social growth, the housing sector, in addition to the housing unit itself, also includes the environment around it. Certainly, identifying housing quality levels in different urban areas is an effective step in explaining the quality of life and the sense of satisfaction of city dwellers. The indicators examined in the present study include indicators related to safe housing with sustainability and structural durability and a suitable living space. In the present article, an attempt is made to evaluate the quality of housing in Urmia metropolis based on available statistics. For this purpose, descriptive and analytical methods have been used based on the data available in the Statistics Center of Iran. The raw data in the Excel spreadsheet was converted to 35 indicators and entered into the SPSS software to perform factor analysis on them. To perform factor analysis, eight factors were identified, four of which were primary and the other secondary. The factors were then entered into the GIS environment and analyzed. The results indicate an unequal and inappropriate distribution of quality housing indicators in the city of Urmia. The results showed that 18. 21% of the statistical areas are among the most deprived areas, 18. 18% are deprived, 53. 53% are average, 18. 13% and 57. 9% are completely deprived. It seems that more attention should be paid to areas 1, 2 and 3 to reduce inequalities to some extent. The results of this study showed that deprived clusters are appeared in regions 3 and 2, and delighted clusters in regions 1 and 4. This situation indicates the existence of class distance and dichotomy in urban space and the difference in having the studied indicators in 2011.