Publications by authors named "John W Wong"

Background: This study aims to present the feasibility of developing a synchrotron-based proton ultra-high dose rate (UHDR) pencil beam scanning (PBS) system.

Methods: The RF extraction power in the synchrotron system was increased to generate 142.4 MeV pulsed proton beams for UHDR irradiation at ~100 nA beam current.

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  • 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.
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Purpose: This work describes the first implementation and in vivo study of ultrahigh-dose-rate radiation (>37 Gy/s; FLASH) effects induced by kilovoltage (kV) x-ray from a rotating-anode x-ray source.

Methods And Materials: A high-capacity rotating-anode x-ray tube with an 80-kW generator was implemented for preclinical FLASH radiation research. A custom 3-dimensionally printed immobilization and positioning tool was developed for reproducible irradiation of a mouse hind limb.

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  • 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.
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  • 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.
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  • 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.
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  • 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.
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  • - FLASH irradiation significantly lowers normal tissue toxicity while keeping tumor control rates stable, but requires further lab studies for effective clinical application.
  • - A novel x-ray irradiation cabinet using high capacity fluoroscopy sources was developed to provide better preclinical research capabilities for FLASH irradiation.
  • - The system achieved high-dose delivery rates (40-240 Gy/s) with accurate depth-dose rates and uniformity, making it suitable for both FLASH and conventional irradiation methods for small animals and cell cultures.
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  • 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.
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  • 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.
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  • - 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.
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  • Researchers developed a new 2D image processing technique to improve motion tracking in ultrasound imaging, specifically for abdominal radiation therapy, overcoming previous limitations.
  • The study involved analyzing 57 anatomical features from 27 sets of 2D ultrasound sequences, including data from both healthy volunteers and a previous challenge dataset.
  • The new tracking method achieved a mean tracking error of 1.14 mm with a quick processing time of 15 ms per frame, showing better reproducibility with position-controlled probes compared to force-controlled ones.
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Objective: We explore whether a knowledge-discovery approach building a Classification and Regression Tree (CART) prediction model for weight loss (WL) in head and neck cancer (HNC) patients treated with radiation therapy (RT) is feasible.

Methods And Materials: HNC patients from 2007 to 2015 were identified from a prospectively collected database Oncospace. Two prediction models at different time points were developed to predict weight loss ≥5 kg at 3 months post-RT by CART algorithm: (1) during RT planning using patient demographic, delineated dose data, planning target volume-organs at risk shape relationships data and (2) at the end of treatment (EOT) using additional on-treatment toxicities and quality of life data.

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  • Researchers developed a bioluminescence tomography (BLT) system to improve imaging for soft-tissue targets in small animal radiation research, addressing limitations of traditional CT methods.
  • The study involved comparing the localization accuracy of this off-line BLT system with an on-line system using small animal irradiators, testing the impact of animal transport between the two imaging setups.
  • Results showed a strong correlation (over 0.95) between imaging from both systems and minimal positional offset (0.2 mm), supporting the feasibility of using an off-line BLT for accurate radiation guidance.
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  • The authors developed a spectrally resolved bioluminescence tomography (BLT) system to improve radiation guidance for soft tissue targets in small animal research, addressing limitations of traditional CT/CBCT methods.
  • The study involved both simulations and experiments to assess the BLT system's effectiveness in localizing single and multiple soft tissue sources, using techniques like multispectral measurements and an optimization algorithm for accurate source distribution reconstruction.
  • Results showed that the BLT system could achieve approximately 1 mm localization accuracy and successfully resolve neighboring sources in various depths, demonstrating its potential application in preclinical studies involving tumor imaging.
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  • This research presents a new online bioluminescence tomography (BLT) system that improves the localization of soft tissue targets for small-animal radiation therapy, addressing the limitations of traditional cone beam computed tomography (CBCT).
  • The BLT system integrates with a small-animal radiation research platform (SARRP), using a specialized 3-mirror setup and advanced algorithms for precise imaging and targeting during radiation delivery.
  • Results showed that BLT offers an average targeting accuracy of 1 mm, demonstrating greater effectiveness for guiding radiation compared to CBCT, with potential applications for various tumors and multiple targets in preclinical studies.
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Radiation therapy is an effective, personalized cancer treatment that has benefited from technological advances associated with the growing ability to identify and target tumors with accuracy and precision. Given that these advances have played a central role in the success of radiation therapy as a major component of comprehensive cancer care, the American Society for Radiation Oncology (ASTRO), the American Association of Physicists in Medicine (AAPM), and the National Cancer Institute (NCI) sponsored a workshop entitled "Technology for Innovation in Radiation Oncology," which took place at the National Institutes of Health (NIH) in Bethesda, Maryland, on June 13 and 14, 2013. The purpose of this workshop was to discuss emerging technology for the field and to recognize areas for greater research investment.

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  • The study describes the development of an integrated imaging system combining cone beam computed tomography (CBCT) and bioluminescence tomography (BLT) for enhanced tumor visualization and guidance during radiation therapy, improving research capabilities in lab settings.
  • It outlines the methods for calibrating the imaging system, which includes CBCT, diffuse optical tomography (DOT), and BLT, by utilizing phantoms and correcting for any imaging inconsistencies to ensure accurate results.
  • The successful calibration confirmed that the integrated system provides precise anatomical details without artifacts, allowing effective localization of tumors for improved radiotherapy outcomes.
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Background: Glioblastoma (GBM) is the most common malignant brain tumor in adults and is associated with a poor prognosis. Cytotoxic T lymphocyte antigen -4 (CTLA-4) blocking antibodies have demonstrated an ability to generate robust antitumor immune responses against a variety of solid tumors. 4-1BB (CD137) is expressed by activated T lymphocytes and served as a co-stimulatory signal, which promotes cytotoxic function.

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Asymmetric bioreduction of an ()-β-cyano-2,4-dienoic acid derivative by ene-reductases allowed a shortened access to a precursor of pregabalin [()-3-(aminomethyl)-5-methylhexanoic acid] possessing the desired configuration in up to 94% conversion and >99% . Deuterium labelling studies showed that the nitrile moiety was the preferred activating/anchor group in the active site of the enzyme over the carboxylic acid or the corresponding methyl ester.

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A reconstruction algorithm for diffuse optical tomography based on diffusion theory and finite element method is described. The algorithm reconstructs the optical properties in a permissible domain or region-of-interest to reduce the number of unknowns. The algorithm can be used to reconstruct optical properties for a segmented object (where a CT-scan or MRI is available) or a non-segmented object.

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  • The synthesis of a smoothened receptor inhibitor is achieved using an efficient, five-step process.
  • Key to this method is an enzymatic transamination combined with dynamic kinetic resolution, creating two stereogenic centers in one step.
  • The final product, an anti amine, is produced with a high diastereomeric ratio (>10:1) and excellent enantiomeric excess (>99%), yielding a 40% overall yield.
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4-{4-[4-Tetrahydrofuran-3-yloxy)-benzo[d]isoxazol-3-yloxymethyl]-piperidin-1-ylmethyl}-tetrahydropyran-4-ol (PF-4995274, TBPT) is a new agent that is a partial agonist of the human serotonin-4 (5-HT4) receptor and is under investigation for neurological disorders. Metabolism of TBPT was examined in vitro in human liver microsomes and human hepatocytes. Metabolites were also identified in the plasma of healthy human subjects in a phase 1 clinical study.

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The asymmetric bioreduction of a library of β-cyanoacrylate esters using ene-reductases was studied with the aim to provide a biocatalytic route to precursors for GABA analogues, such as pregabalin. The stereochemical outcome could be controlled by substrate-engineering through size-variation of the ester moiety and by employing stereochemically pure (E)- or (Z)-isomers, which allowed to access both enantiomers of each product in up to quantitative conversion in enantiomerically pure form. In addition, stereoselectivities and conversions could be improved by mutant variants of OPR1, and the utility of the system was demonstrated by preparative-scale applications.

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