Abstract Background A novel CT-linac (kilovolt fan-beam CT-linac) has been introduced into total marrow and lymphoid irradiation (TMLI) treatment. Its integrated kilovolt fan-beam CT (kV FBCT) can be used not only for image guidance (IGRT) but also to re-calculate the dose. Purpose This study reported our clinical routine on performing TMIL treatment on the CT-linac, as well as dose distribution comparison between planned and re-calculated based on IGRT FBCT image sets. Methods 11 sets of data from 5 male and 6 female patients who had underwent the TMLI treatment with uRT-linac 506c were selected for this study. The planning target volumes consist of all skeletal bones exclusion of the mandible and lymphatic sanctuary sites. A planned dose of 10 Gy was prescribed to all skeletal bones exclusion of the mandible in two fractions and 12 Gy in two fractions was prescribed to lymphatic sanctuary sites. Each TMLI plan contained two sub-plans, one dynamic IMRT for the upper body and the other VMAT for the lower extremity. Two attempts were made to obtain homogeneous dose in the overlapping region, i.e., applying two plans with different isocenters for the treatment of two fractions, and using a dose gradient matching scheme. The CT scans, including planning CT and IGRT FBCT, were stitched to a whole body CT scan for dose distribution evaluation. Results The average beam-on time of Planupper is 30.6 min, ranging from 24.9 to 37.5 min, and the average beam-on time of Planlower is 6.3 min, ranging from 5.7 to 8.2 min. For the planned dose distribution, the 94.79% of the PTVbone is covered by the prescription dose of 10 Gy (V10), and the 94.68% of the PTVlymph is covered by the prescription dose of 12 Gy (V12). For the re-calculated dose distribution, the 92.17% of the PTVbone is covered by the prescription dose of 10 Gy (V10), and the 90.07% of the PTVlymph is covered by the prescription dose of 12 Gy (V12). The results showed that there is a significant difference ( p < 0.05) between planning V10, V12 and delivery V10, V12. There is no significant difference ( p > 0.05) between planned dose and re-calculated dose on selected organs, except for right lens ( p < 0.05, Dmax). The actual delivered maximum dose of right lens is apparently larger than the planned dose of it. Conclusion TMLI treatment can be performed on the CT-linac with clinical acceptable quality and high efficiency. Evaluation of the recalculated dose on IGRT FBCT suggests the treatment was delivered with adequate target coverage.
A controllable multi-sector array beam is proposed in this Letter. The beam can be generated with the metalens phase. The intensity distribution of the beam at the focal plane is analyzed in detail. The influence of the parameters a and l on the focal field distribution is discussed. The theoretical and experimental results demonstrate that the parameter a affects the size of the beam, and the additional factor l can adjust the sub-region number of the multi-sector array beams. The beam shows potential for use in optical manipulation and image transmission.
Multimode interference (MMI) couplers based on silicon slot-waveguide structures have received widespread attention in recent years. The key issues that need to be addressed are the size and loss of such devices. This study introduces a 1 × 3 silicon-based slot-waveguide multimode interference power splitter. The device uses a gallium-nitride slot-waveguide structure to reduce the length of the coupling region and decrease additional losses. To reduce the width of the coupling region, the multimode interference coupling area is designed with a parabolic-shaped structure. The introduction of a tapered structure between the input/output waveguides and the coupling region improves additional losses and non-uniformity. Furthermore, we conducted an analysis of the fabrication tolerances of the coupling region. In this paper, we use mode solution to simulate the design of the device in the 1550 nm optical wavelength range. The eigenmode expansion method is used to simulate and optimize the parameters of the device. The device is simulated using the eigenmode expansion solver. The simulation results show that the total length of the coupling region for the device is only 4 μm. The normalized transmission of the device is 0.992, and its excess loss and imbalance are 0.036 dB and 0.003 dB, respectively. The proposed power splitter can be applied to integrated optical circuit design, optical sensing, and optical power measurement.
A novel speckle reduction technique for digital holography is proposed.Multiple off-axis holograms are recorded using a circularly polarized illumination beam and a rotating linearly polarized reference beam.The speckle noise in the reconstructed images is suppressed by averaging these fields.We demonstrate the effectiveness of this technique experimentally and conduct additional statistical evaluation.
In the process of multi-energy system optimal scheduling, due to the high data processing requirements of the multi-energy devices and loads and the complexity of the operating states of the multi-energy devices, the scheduling optimization of the system is to some extent more difficult. To address this problem, this paper proposes a regional multi-energy system optimal scheduling model based on the theory of cloud-edge collaboration. First, based on intelligent data sensors, a cloud-edge cooperative scheduling framework of the regional multi-energy system is constructed. Then, the physical model of operating state data of multi-energy system equipment and the allocation mechanism of system scheduling tasks are studied. With the cloud service application layer and the edge computing layer as the upper and lower optimization scheduling layers, the double-layer optimization scheduling model of the regional multi-energy system is established. The objectives of the model are optimal scheduling cost and minimum delay of scheduling data transmission. The multi-objective whale optimization algorithm is used to solve the model. Finally, a simulation model is built for verification. The simulation results show that the scheduling model established in this paper can effectively improve the scheduling data processing capability and improve the economy of regional multi-energy system scheduling.
A Bessel-Gaussian beam carrying a new kind of power-exponent phase is proposed and demonstrated experimentally in this paper. The focal field, propagation characteristic and the transverse energy flow of the proposed beam are analyzed in detail. The results show that the number of intensity petals on the focal plane is dependent on the topological charge l and the transverse energy distribution in the focal region can be adjusted with the power exponent n. Furthermore, the intensity distribution can be also adjusted by the distribution factor β. The proposed Bessel-Gaussian beam with the new kind of power-exponent-phase vortices can be useful for optical manipulation.
Helico-conical vortex (HCV) beams are a kind of orbital angular momentum-carrying beam whose phase profile has a non-separable azimuthal and radial dependence. In this Letter, we introduce a lens phase into the helico-conical phase to measure the topological charge carried by the helico-conical beam. The focal-field intensity distributions of the beam obtained from the superimposition of the helico-conical phase and the lens phase are analyzed theoretically and experimentally. The experimental findings are in good agreement with the simulation results. The results demonstrate that a certain number of elliptical dark regions are embedded in the intensity patterns and the number of dark regions is equal to the amount of topological charge carried by the HCV beam. Meanwhile, the tilt direction of the elliptical dark regions can determine the sign of the topological charges. This method will have potential applications in the field of light field modulation.
We proposed a method to measure the topological charge of a vortex beam by using the self-rotating beam phase in this Letter. We investigated the far-field intensity patterns of the vortex beams passing through a phase hologram of the self-rotating beam with n = +2 theoretically and experimentally. The results demonstrate that the far-field intensity patterns cannot exhibit bright stripes when the topological charge of the vortex is positive (i.e., n ⋅ l > 0) and the calculated ratio relationship ξ can be used to identify the topological charge of the vortex beam. Differently, it can be found that the far-field intensity patterns exhibit several bright stripes when the topological charge of the vortex is negative (i.e., n ⋅ l < 0) and the number N of the bright stripes is equal to |l|−1(l represents the topological charge of the vortex beam). The experimental results are in good agreement with the theoretical ones. This method may inspire further research in the field of self-rotating beams.
A controllable helico-conical beam is proposed in this paper. The intensity patterns and the local spatial frequency of the controllable helico-conical beams in the focal region are analyzed in detail. The results show that the length of the helico-conical beams can be customized by the variable parameter k, and the angular dimension of the bored spiral trajectory is dependent on the proportion k/l. Moreover, the focal-field energy flow density and orbital angular momentum distributions of the controllable helico-conical beams are also analyzed. The proposed helico-conical beams with controllable lengths can be potentially applied in the field of optical guiding.
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