Berthelsenklemmensen1967
9 to 2.8 for GD-302M. Both RGD responses exhibited a good correlation with the Al-HVL for the given QI. K
measured by RGDs for each beam quality with a QI of 0.5 was in the range of -5%~0.8% for GD-352M and -1.8%~3% for GD-302M, relative to the chamber measurements.
The RGD response was indicated as a function of the Al-HVL for the given QI, and it presented a good correlation with the Al-HVL.
The RGD response was indicated as a function of the Al-HVL for the given QI, and it presented a good correlation with the Al-HVL.The lack of mailed dosimetry audits of proton therapy centres in Europe has encouraged researchers of EURADOS Working Group 9 (WG9) to compare response of several existing passive detector systems in therapeutic pencil beam scanning. Alanine Electron Paramagnetic Resonance dosimetry systems from 3 different institutes (ISS, Italy; UH, Belgium and IFJ PAN, Poland), natLiFMg, Ti (MTS-N) and natLiFMg, Cu, P (MCP-N) thermoluminescent dosimeters (TLDs), GD-352M radiophotoluminescent glass dosimeters (RPLGDs) and Al2O3C optically stimulated dosimeters (OSLDs) were evaluate. Dosimeter repeatability, batch reproducibility and response in therapeutic Pencil Beam Scanning were verified for implementation as mail auditing system. Alanine detectors demonstrated the lowest linear energy transfer (LET) dependence with an agreement between measured and treatment planning system (TPS) dose below 1%. The OSLDs measured on average a 6.3% lower dose compared to TPS calculation, with no significant difference between varying modulations and ranges. Both GD-352M and MCP-N measured a lower dose than the TPS and luminescent response was dependent on the LET of the therapeutic proton beam. Thermoluminescent response of MTS-N was also found to be dependent on the LET and a higher dose than TPS was measured with the most pronounced increase of 11%. As alanine detectors are characterized by the lowest energy dependence for different parameters of therapeutic pencil beam scanning they are suitable candidates for mail auditing in proton therapy. The response of luminescence detector systems have shown promises even though more careful calibration and corrections are needed for its implementation as part of a mailed dosimetry audit system.
The purpose of this work was to present a new single-arc mixed photon (6&18MV) VMAT (SAMP) optimization framework that concurrently optimizes for two photon energies with corresponding partial arc lengths.
Owing to simultaneous optimization of energy dependent intensity maps and corresponding arc locations, the proposed model poses nonlinearity. Unique relaxation constraints based on McCormick approximations were introduced for linearization. Energy dependent intensity maps were then decomposed to generate apertures. Feasibility of the proposed framework was tested on a sample of ten prostate cancer cases with lateral separation ranging from 34 cm (case no.1) to 52cm (case no.6). The SAMP plans were compared against single energy (6MV) VMAT (SE) plans through dose volume histograms (DVHs) and radiobiological parameters including normal tissue complication probability (NTCP) and equivalent uniform dose (EUD).
The contribution of higher energy photon beam optimized by the algorithm demonstrated an increase for cases with a lateral separation >40cm. SAMP-VMAT notably improved bladder and rectum sparing in large size cases. Compared to single energy, SAMP-VMAT plans reduced bladder and rectum NTCP in cases with large lateral separation. With the exception of one case, SAMP-VMAT either improved or maintained femoral heads compared to SE-VMAT. SAMP-VMAT reduced the nontarget tissue integral dose in all ten cases.
A single-arc VMAT optimization framework comprising mixed photon energy partial arcs was presented. Overall results underline the feasibility and potential of the proposed approach for improving OAR sparing in large size patients without compromising the target homogeneity and coverage.
A single-arc VMAT optimization framework comprising mixed photon energy partial arcs was presented. Overall results underline the feasibility and potential of the proposed approach for improving OAR sparing in large size patients without compromising the target homogeneity and coverage.The structural evolution of growing thin colloidal crystals in a confined space via the convective assembly technique has been investigated. The thin colloidal crystals were grown in a wedge-shaped cell, where the height of the cell increased with increased crystal growth. Triangle and square patterns, denoted as [111]- and [100]-oriented grains, respectively, were formed alternately as the height of the cell increased. The structural transformation was associated with an increase in the number of layers when the n-layer [100]-oriented grains changed to n + 1-layer [111]-oriented grains. Between the different grain structures, a stripe pattern was observed, which was a transitional region, where particle configuration gradually changed. The structural transformation occurred through the continuous change of particle configuration rather than through the abrupt formation of a grain boundary. The interval of the strip pattern lengthened as the number of layers increased, which is understood to be the structure with the highest packing density. The findings of the study give a better insight into convective assembly in a confined space, and also contribute to the greater structural control of colloidal crystals, useful for a number of applications.A metal-free carbon catalyst, melem-cyanuric acid complex (MCAC), was prepared by hydrogen bonding assembly and further explored as a novel bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The proposed MCAC network presented nanosheet-like structure, nitrogen-rich, and large specific surface area, which are close to the natures of graphitic carbon nitride (g-C3N4) and N-doped reduced graphene oxide (N-rGO), but giving much more defect active sites and regular framework structure. SBI-115 antagonist Compared with the g-C3N4, N-rGO and other reported carbon-nitride electrocatalysts, the MCAC nanosheets exhibited a lower overpotential of 1.45 V at a current density of 10 mA cm-2 for OER, along with a higher half-potential of 0.8 V and larger limit current density of -6.0 mA cm-2 for ORR. Density functional theory calculation revealed that the melem N atoms bonded with cyanurate greatly enhanced the OER activity by increasing the interaction between catalysts and intermediates. Furthermore, as a metal-free electrocatalyst, MCAC displayed superior reversible oxygen electrocatalytic activity, giving a small overpotential difference (0.