Weiyuan Sun

All Publications

• Robust treatment planning for small animal radio-neuromodulation using focused kV x-ray beams. Medical physics Qiu, C., Gu, W., Yan, H., Sun, W., Wang, Y., Wen, Q., Sheng, K., Liu, W. 2024

  Abstract

  In preclinical radio-neuromodulation research, small animal experiments are pivotal for unraveling radiobiological mechanism, investigating prescription and planning techniques, and assessing treatment effects and toxicities. However, the target size inside a rat brain is typically in the order of sub-millimeters. The small target inside the visual cortex neural region in rat brain with a diameter of around 1 mm was focused in this work to observe the physiological change of this region. Delivering uniform doses to the small target while sparing health tissues is challenging. Focused kV x-ray technique based on modern x-ray polycapillary focusing lens is a promising modality for small animal radio-neuromodulation.The current manual planning method could lead to sub-optimal plans, and the positioning uncertainties due to mechanical accuracy limitations, animal immobilization, and robotic arm motion are not considered. This work aims to design a robust inverse planning method to optimize the intensities of focused kV x-ray beams located in beam trajectories to irradiate small mm-sized targets in rat brains for radio-neuromodulation.Focused kV x-ray beams were generated through polycapillary x-ray focusing lenses on achieving small (≤0.3 mm) focus perpendicular to the beam. The beam trajectories were manually designed in 3D space in scanning-while-rotating mode. Geant4 Monte Carlo (MC) simulation generated a dose calculation matrix for each focused kV x-ray beam located in beam trajectories. In the proposed robust inverse planning method, an objective function combining a voxel-wise stochastic programming approach and L1 norm regularization was established to overcome the positioning uncertainties and obtain a high-quality plan. The fast iterative shrinkage thresholding algorithm (FISTA) was utilized to solve the objective function and obtain the optimal intensities. Four cases were employed to validate the feasibility and effectiveness of the proposed method. The manual and non-robust inverse planning methods were also implemented for comparison.The proposed robust inverse planning method achieved superior dose homogeneity and higher robustness against positioning uncertainties. On average, the clinical target volume (CTV) homogeneity index (HI) of robust inverse plan improved to 13.3 from 22.9 in non-robust inverse plan and 53.8 in manual plan if positioning uncertainties were also present. The average bandwidth at D90 was reduced by 6.5 Gy in the robust inverse plan, compared to 9.6 Gy in non-robust inverse plan and 12.5 Gy in manual plan. The average bandwidth at D80 was reduced by 3.4 Gy in robust inverse plan, compared to 5.5 Gy in non-robust inverse plan and 8.5 Gy in manual plan. Moreover, the dose delivery time of manual plan was reduced by an average reduction of 54.7% with robust inverse plan and 29.0% with non-robust inverse plan.Compared to manual and non-robust inverse planning methods, the robust inverse planning method improved the dose homogeneity and delivery efficiency and was resistant to the uncertainties, which are crucial for radio-neuromodulation utilizing focused kV x-rays.

  View details for DOI 10.1002/mp.17023

  View details for PubMedID 38461033

• Grating-free quantitative phase retrieval for x-ray phase-contrast imaging with conventional sources. Biomedical physics & engineering express Sun, W., Pyakurel, U., MacDonald, C. A., Petruccelli, J. C. 2022; 8 (5)

  Abstract

  X-ray phase-contrast imaging can display subtle differences in low-density materials (e.g. soft tissues) more readily than conventional x-ray imaging. However, producing x-ray phase images requires significant spatial coherence of the beam which in turn requires highly specialized sources such as synchrotrons, small and low power microfocus sources, or complex procedures, such as multiple exposures with several carefully stepped precision gratings. To find appropriate approaches for producing x-ray phase-contrast imaging in a clinically meaningful way, we employed a grating-free method that utilized a low-cost, coarse wire mesh and simple processing. This method relaxes the spatial coherence constraint and allows quantitative phase retrieval for not only monochromatic but also polychromatic beams. We also combined the mesh-based system with polycapillary optics to significantly improve the accuracy of quantitative phase retrieval.

  View details for DOI 10.1088/2057-1976/ac741d

  View details for PubMedID 35623335

• Phase and dark field imaging with mesh-based structured illumination and polycapillary optics. Medical physics Pyakurel, U., Sun, W., Cheung, P., D'Moore, D., Zhang, X., MacDonald, C. A., Petruccelli, J. C. 2021

  Abstract

  PURPOSE: X-ray phase and dark field imaging have been shown to improve the diagnostic capabilities of x-ray systems. However, these methods have found limited clinical use due to the need for multiple precision gratings with limited field of view or requirements on x-ray coherence that may not be easily translated to clinical practice. This work aims to develop a practicable x-ray phase and dark field imaging system that could be translated and practiced in the clinic.METHODS: This work employs a conventional source to create structured illumination with a simple wire mesh. A mesh-shifting algorithm is used to allow wider Fourier windowing to enhance resolution. Deconvolution of the source spot width and camera resolution improves accuracy. Polycapillary optics are employed to enhance coherence. The effects of incorporating optics with two different focal lengths are compared. Information apparent in enhanced absorption images, phase images and dark field images of fat embedded phantoms were compared and subjected to a limited ROC study. The dark field images of the moist and dry porous object (sponges) were compared.RESULTS: The mesh-based phase and dark field imaging system constructs images with three different information types: scatter free absorption images, differential phase images and scatter magnitude/dark field images, simultaneously from the same original image. The polycapillary optic enhances the coherence of the beam. The deblurring technique corrects the phase signal error due to geometrical blur and the limitation of the camera MTF and removes image artifacts to improve the resolution in a single shot. The mesh-shifting method allows the use of a wider Fourier processing window, which gives even higher resolution, at the expense of increased dose. The limited ROC study confirms the efficacy of the system over the conventional system. Dark field images of moist and dry porous object show the significance of the system in the imaging of lung infections.CONCLUSION: The mesh-based x-ray phase and dark field imaging system is an inexpensive and easy setup in terms of alignment and data acquisition and can produce phase and dark field images in a single shot with wide field of view. The system shows a significant potential use for diagnostic imaging in a clinical setting. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/mp.15247

  View details for PubMedID 34554583

• Dosimetry Modeling of Focused kV X-ray Radiotherapy for Wet Age-related Macular Degeneration. Medical physics Yan, H. n., Sun, W. n., Mruthyunjaya, P. n., Beadle, B. n., Yu, W. n., Kanwal, B. n., MacDonald, C. A., Liu, W. n. 2020

  Abstract

  Wet (neovascular) age-related macular degeneration (AMD) is the leading cause of blindness in the USA. The mainstay treatment requires monthly intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs, associated with multiple visits, high cost, and the risk of procedural injury and infection. Anti-VEGF drugs inhibit the formation of neovasculature but do not directly attack it. Radiotherapy can destroy neovasculature and potentially also inhibit wet-AMD associated inflammation and fibrosis not addressed by VEGF inhibitors. However, the current collimation-based radiotherapy device uses fixed 4 mm beams, which are prone to overtreat or undertreat the choroidal neovascularization (CNV) lesions because of their various sizes and shapes. This simulation study evaluates personalized conformal treatment with focused kV radiation using cutting-edge polycapillary x-ray optics.Simulation of the polycapillary optics was achieved via Monte Carlo (MC)-based 3D geometric ray tracing. Phase-space files modeling the focused photons were generated. The method was previously verified by phantom measurements. The ultrasmall ~0.2 mm beam focal spot perpendicular to the beam direction enables spatially fractionated grid therapy, which has been shown to preferentially damage abnormal neovascular blood vessels vs normal ones. Geant4-based MC simulations of scanning while rotating beam delivery were performed to conformally treat three clinical cases of large, medium, and small CNV lesions with regular and grid deliveries. Dose delivery uncertainties due to positioning errors were analyzed, including ±0.75 mm displacement in the three orthogonal directions and ±5° vertical/horizontal rotation of the eyeball.The simulated CNV treatments by 60 kVp focused x-ray beams show highly-conformal delivery of dose to the lesion plus margin (0.75 mm) with sharp dose fall-offs and controllable spatial modulation patterns. The 90%-10% isodose penumbra is <0.5 mm. With a 16 Gy prescription dose to the lesions, the critical structure doses are well below the tolerance. The average CNV dose varies within 10% (mostly within 4%) due to 0.75-mm linear displacements and 5-degree gaze angle rotation of the eyeball.Focused kV technique allows personalized treatment of CNV lesions and reduces unwanted radiation to adjacent healthy tissue. The simulated dose distribution is superior to currently available techniques.

  View details for DOI 10.1002/mp.14404

  View details for PubMedID 32683708

• Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Sun, X., Liu, Z., Sun, T., Yi, L., Sun, W., Li, F., Jiang, B., Ma, Y., Ding, X. 2015; 802: 5-9

  View details for DOI 10.1016/j.nima.2015.08.043

  View details for Web of Science ID 000362283200002

• Numerical design of X-ray tabletop Talbot interferometer using polycapillary optics as two-dimensional gratings with high aspect ratio OPTICS COMMUNICATIONS Sun, W., Liu, Z., Sun, T., Sun, X., Li, F., Jiang, B., Ding, X. 2015; 356: 202-207

  View details for DOI 10.1016/j.optcom.2015.07.076

  View details for Web of Science ID 000362603600035

• Numerical design of polycapillary X-ray optics as both a focusing X-ray lens and a vacuum window VACUUM Jiang, B., Liu, Z., Sun, W., Sun, X., Li, F., Ma, Y., Sun, T. 2015; 121: 1-4

  View details for DOI 10.1016/j.vacuum.2015.07.010

  View details for Web of Science ID 000362619000001

• Application of polycapillary x ray lens to eliminate both the effect of x ray source size and scatter of the sample in laboratory tomography CHINESE OPTICS LETTERS Sun, X., Liu, Z., Sun, T., Yi, L., Sun, W., Li, F., Jiang, B., Ma, Y., Ding, X. 2015; 13 (9)

  View details for DOI 10.3788/COL201513.093401

  View details for Web of Science ID 000362843500020

• A confocal three-dimensional micro X-ray scattering technology based on Rayleigh to Compton ratio for identifying materials with similar density and different weight percentages of low-Z elements RADIATION PHYSICS AND CHEMISTRY Li, F., Liu, Z., Sun, T., Yang, C., Sun, X., Sun, W., He, J., Ding, X. 2015; 112: 163-168

  View details for DOI 10.1016/j.radphyschem.2015.03.042

  View details for Web of Science ID 000354139700025

• In situ analysis of electrocrystallization process of metal electrodeposition with confocal energy dispersive X-ray diffraction based on polycapillary X-ray optics NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Li, F., Liu, Z., Sun, T., Yang, C., Sun, W., Sun, X., Ma, Y., Ding, X. 2015; 785: 201-205

  View details for DOI 10.1016/j.nima.2015.03.015

  View details for Web of Science ID 000352815400031

• Application of confocal X-ray fluorescence micro-spectroscopy to the investigation of paint layers APPLIED RADIATION AND ISOTOPES Sun, T., Liu, Z., Wang, G., Ma, Y., Peng, S., Sun, W., Li, F., Sun, X., Ding, X. 2014; 94: 109-112

  Abstract

  A confocal micro X-ray fluorescence (MXRF) spectrometer based on polycapillary X-ray optics was used for the identification of paint layers. The performance of the confocal MXRF was studied. Multilayered paint fragments of a car were analyzed nondestructively to demonstrate that this confocal MXRF instrument could be used in the discrimination of the various layers in multilayer paint systems.

  View details for DOI 10.1016/j.apradiso.2014.07.019

  View details for Web of Science ID 000345477700019

  View details for PubMedID 25151613

• Measurement of grain size of polycrystalline materials with confocal energy dispersive micro-X-ray diffraction technology based on polycapillary X-ray optics NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Sun, W., Liu, Z., Sun, T., Peng, S., Ma, Y., Li, F., Sun, X., Ding, X. 2014; 764: 1-6

  View details for DOI 10.1016/j.nima.2014.07.012

  View details for Web of Science ID 000341987000001

• Numerical design of in-line X-ray phase-contrast imaging based on ellipsoidal single-bounce monocapillary NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Sun, W., Liu, Z., Sun, T., Peng, S., Ma, Y., Ding, X. 2014; 746: 33-38

  View details for DOI 10.1016/j.nima.2014.02.013

  View details for Web of Science ID 000334073900006

• Application of confocal technology based on polycapillary X-ray optics in three-dimensional diffraction scanning analysis NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Sun, T., Liu, H., Liu, Z., Peng, S., Ma, Y., Sun, W., Luo, P., Ding, X. 2014; 323: 25-29

  View details for DOI 10.1016/j.nimb.2014.01.013

  View details for Web of Science ID 000333497800005

• Performance of polycapillary X-ray optics for confocal energy-dispersive small-angle X-ray scattering JOURNAL OF APPLIED CRYSTALLOGRAPHY Sun, T., Peng, S., Liu, Z., Sun, W., Ma, Y., Ding, X. 2013; 46: 1880-1883

  View details for DOI 10.1107/S0021889813027088

  View details for Web of Science ID 000327070000042

• Adjustment of confocal configuration for capillary X-ray optics with a liquid secondary target NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Peng, S., Liu, Z., Sun, T., Ma, Y., Sun, W., Zhao, W., He, J., Zhao, G., Ding, X. 2013; 729: 565-568

  View details for DOI 10.1016/j.nima.2013.08.044

  View details for Web of Science ID 000325753500079

• [Application of confocal micro-beam X-ray fluorescence in nondestructive scanning analysis of the distribution of elements in a single hair]. Guang pu xue yu guang pu fen xi = Guang pu Liu, H., Liu, Z., Sun, T., Peng, S., Zhao, W., Sun, W., Li, Y., Lin, X., Zhao, G., Luo, P., Ding, X. 2013; 33 (11): 3147-50

  Abstract

  The confocal micro X-ray fluorescence (XRF) based on polycapillary X-ray lens and conventional X-ray source was used to carry out the scanning analysis of the distribution of the elements in a single hair. The elemental distribution in the single hair was obtained. In the confocal micro XRF technology, the output focal spot of the polycapillary focusing X-ray lens and the input focal spot of the polycapillary parallel X-ray lens were adjusted confocally. The detector could only detect the X-rays from the overlapping foci. This confocal structure decreased the effects of the background on the X-ray spectra, and was accordingly helpful for improving the accuracy of this XRF technology. A polycapillary focusing X-ray lens with a high gain in power density was used to decrease the requirement of power of the X-ray source used in this confocal technology, and made it possible to perform such confocal micro XRF analysis by using the conventional X-ray source with low cost. Experimental results indicated that the confocal micro X-ray fluorescence based on polycapillary X-ray lens had potential applications in analyzing the elemental distribution of individual hairs.

  View details for PubMedID 24555400

• Performances for confocal X-ray diffraction technology based on polycapillary slightly focusing X-ray optics NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Liu, H., Liu, Z., Sun, T., Peng, S., Ma, Y., Sun, W., Li, Y., Lin, X., Zhao, W., Zhao, G., Luo, P., Pan, Q., Ding, X. 2013; 723: 1-4

  View details for DOI 10.1016/j.nima.2013.05.002

  View details for Web of Science ID 000321709700001