Publications by authors named "Xiangkun Xu"
Bioluminescence tomography (BLT) improves upon commonly-used 2D bioluminescence imaging by reconstructing 3D distributions of bioluminescence activity within biological tissue, allowing tumor localization and volume estimation-critical for cancer therapy development. Conventional model-based BLT is computationally challenging due to the ill-posed nature of the problem and data noise. We introduce a self-supervised hybrid neural network (SHyNN) that integrates the strengths of both conventional model-based methods and machine learning (ML) techniques to address these challenges.
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- Recent advancements in radiotherapy for pancreatic cancer highlight the need for better research models to enhance our understanding of radiation treatment's effects on this cancer type.
- Cone-beam CT imaging is limited in its ability to provide soft tissue contrast and is affected by pancreatic motion, leading to potential damage to healthy tissues during treatment.
- The new bioluminescence tomography (BLT)-guided system shows improved localization accuracy for pancreatic tumors and allows for more precise radiation planning while minimizing damage to surrounding healthy tissue.
Article Synopsis
- Cone-beam computed tomography (CBCT) techniques face challenges in targeting soft tissue, which limits accuracy in small animal radiation studies.
- To improve localization, the researchers developed a new bioluminescence tomography-guided system (BLT, MuriGlo) aimed at enhancing imaging for pre-clinical research.
- The study included various tests to evaluate the system's performance and precision, ultimately providing a guideline for researchers on using BLT in radiation studies.
Article Synopsis
- Researchers developed a bioluminescence tomography (BLT) system to identify soft tissue targets in preclinical radiotherapy studies.
- The system uses specific thresholds and margins to define target volumes, enhancing targeting accuracy.
- This technology allows for more precise conformal irradiation of cancerous tissues.
Mobile bioluminescence tomography-guided system for pre-clinical radiotherapy research.
Biomed Opt Express
September 2022
Article Synopsis
- A cone-beam computed tomography system is less effective at identifying soft tissue targets due to low imaging contrast, prompting the development of a mobile bioluminescence tomography (BLT) system for improved localization in small animal irradiation.
- The BLT combines a light propagation model with optimization to generate detailed images of internal bioluminescent sources, achieving target localization accuracy within 1 mm.
- This technology offers researchers a new approach for precise, biology-guided radiation treatment for cancerous tissues by selecting optimal threshold and margin settings for target volumes.
Article Synopsis
- Bioluminescence imaging and tomography (BLT) are techniques used to study biological activities in mice, but their accuracy is limited by unknown optical properties of the tissues involved.
- A new optimization algorithm has been developed to simultaneously determine both the optical properties and the location of bioluminescent sources using surface measurements.
- The algorithm can accurately locate bioluminescence sources within 1 mm, achieving results comparable or superior to existing methods that require prior knowledge of optical parameters, thus enhancing molecular imaging capabilities.
Article Synopsis
- Several groups are working on small-animal irradiators that mimic human radiation therapy, primarily using cone-beam computed tomography (CBCT) for guidance.
- While CBCT is effective, it struggles with identifying soft tissue targets due to low image contrast; bioluminescence imaging (BLI) offers better contrast but is limited when used on the animal's surface.
- To overcome these challenges, the authors introduce a method called quantitative bioluminescence tomography (QBLT), which integrates 3D imaging with the small animal radiation research platform (SARRP) to improve tumor volume quantification for precise irradiation guidance.
Quantitative Bioluminescence Tomography-Guided Conformal Irradiation for Preclinical Radiation Research.
Int J Radiat Oncol Biol Phys
December 2021
Article Synopsis
- The study developed a high-contrast quantitative bioluminescence tomography (QBLT) system to improve target localization in radiation therapy, addressing limitations of conventional cone beam computed tomography (CBCT) that struggles with soft tissue imaging.
- QBLT utilizes advanced imaging techniques to accurately quantify bioluminescence signals in vivo, significantly enhancing radiation treatment planning for brain tumors like glioblastoma.
- Results showed QBLT could localize tumors with an accuracy of within 1 mm, improving tumor coverage from 75% to 97.9% and effectively delivering the prescribed radiation dose while minimizing damage to surrounding healthy tissue.
Article Synopsis
- A genetically engineered mouse model (GEMM) for pancreatic ductal adenocarcinoma (PDAC) is being used to enhance our understanding of radiotherapy techniques suitable for pancreatic cancer treatment.
- The study highlights the limitations of cone beam CT (CBCT) for localizing PDAC, particularly in low-contrast environments, and introduces bioluminescence tomography (BLT) as a more effective alternative for guiding radiation treatment.
- Initial findings indicate that BLT can accurately determine the tumor's location within 2 mm and volume within 25% accuracy, providing a solid foundation for future radiation research using the PDAC-GEMM model.
Article Synopsis
- The proposed mobile fluorescence tomography (mFT) system aims to enhance pre-clinical radiotherapy research.
- It will help accurately locate tumors and functional targets for radiation treatment.
- Additionally, the mFT system will allow for ongoing evaluation of treatment effectiveness over time.
In Vivo Bioluminescence Tomography Center of Mass-Guided Conformal Irradiation.
Int J Radiat Oncol Biol Phys
March 2020
Article Synopsis
- - The study introduces a new method of using three-dimensional bioluminescence tomography (BLT) in conjunction with a small animal radiation research platform (SARRP) to improve targeting accuracy for radiation therapy in a glioblastoma mouse model, particularly where poor imaging contrast exists.
- - By optimizing the optical absorption coefficients in BLT, the researchers aimed to enhance the localization of the tumor's center of mass, ultimately allowing for more precise delivery of radiation therapy.
- - Results indicated that the BLT-guided method successfully achieved a target volume estimated to cover over 95% of the tumor, with a deviation of approximately 1 mm between the BLT method and traditional imaging techniques.
Quantum adiabatic evolutions find a broad range of applications in quantum physics and quantum technologies. The traditional form of the quantum adiabatic theorem limits the speed of adiabatic evolution by the minimum energy gaps of the system Hamiltonian. Here, we experimentally show using a nitrogen-vacancy center in diamond that, even in the presence of vanishing energy gaps, quantum adiabatic evolution is possible.
View Article and Find Full Text PDFQuantitative bioluminescence tomography using spectral derivative data.
Biomed Opt Express
September 2018
Article Synopsis
- Bioluminescence imaging (BLI) is an optical technique that measures light emitted from biological activity, often used in studies to track disease progression and develop treatments, particularly in cancer research.
- The goal of bioluminescence tomography (BLT) is to create accurate maps of light source distribution within the body, which requires overcoming challenges in light propagation modeling and detector optics.
- A new method introduced in this study utilizes the spectral derivative of BLI images to significantly reduce reconstruction errors, improving the accuracy of source intensity mapping from 49% to 4%.
The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation.
View Article and Find Full Text PDFThe measurement of the microwave field is crucial for many developments in microwave technology and related applications. However, measuring microwave fields with high sensitivity and spatial resolution under ambient conditions remains elusive. In this work, we propose and experimentally demonstrate a scheme to measure both the strength and orientation of the microwave magnetic field by utilizing the quantum coherent dynamics of nitrogen vacancy centres in diamond.
View Article and Find Full Text PDFIt is theoretically known that the quantum interference of a long sequence of Landau-Zener transitions can result in Rabi oscillations. Because of its stringent requirements, however, this phenomenon has never been experimentally observed in the time domain. Using a nitrogen-vacancy (NV) center spin in isotopically purified diamond, we observed the Rabi oscillations resulting from more than 100 Landau-Zener processes.
View Article and Find Full Text PDFIn order to achieve reliable quantum-information processing results, we need to protect quantum gates along with the qubits from decoherence. Here we demonstrate experimentally on a nitrogen-vacancy system that by using a continuous-wave dynamical decoupling method, we might not only prolong the coherence time by about 20 times but also protect the quantum gates for the duration of the controlling time. This protocol shares the merits of retaining the superiority of prolonging the coherence time and at the same time easily combining with quantum logic tasks.
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