Dual Imaging - a New Frontier in MRI (Interview with Dr. Ashok Ajoy)
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-04-11 |
| Journal | Berkeley Scientific Journal |
| Authors | Andrew Delaney, Lexie Ewer, Esther Lim |
| Institutions | Berkeley College, University of California, Berkeley |
| Analysis | Full AI Review Included |
Dual Imaging: A New Frontier in MRI - Technical Analysis and 6CCVD Solutions
Section titled âDual Imaging: A New Frontier in MRI - Technical Analysis and 6CCVD SolutionsâExecutive Summary
Section titled âExecutive SummaryâThis research highlights the revolutionary potential of using MPCVD diamond microparticles containing Nitrogen Vacancy (NV) centers to achieve âdual-mode imaging,â significantly enhancing Magnetic Resonance Imaging (MRI) capabilities for biological and physical sciences.
- Core Value Proposition: Utilizing laser-assisted hyperpolarization of 13C nuclear spins in diamond to overcome the fundamental sensitivity and resolution limits of conventional MRI.
- Key Achievement: Demonstrated simultaneous high-resolution optical imaging (via NV fluorescence) and high-sensitivity 13C MRI, enabling background-free visualization of diamond particles.
- Performance Gain: Hyperpolarization resulted in a signal increase up to a million times greater than alignment achieved using standard magnetic fields (1.5 T to 7 T).
- Mechanism: NV centers act as spin-photon couplers, transferring polarization from absorbed laser light to neighboring 13C nuclei, which are then detected by MRI.
- Application Focus: Developing quantum-enhanced NMR/MRI technologies for deep tissue imaging, molecular sensing, and early cancer detection.
- Material Requirement: High-quality, isotopically enriched 13C diamond material with precisely controlled NV defect concentrations is essential for maximizing polarization efficiency and coherence time.
Technical Specifications
Section titled âTechnical SpecificationsâThe following table extracts key performance metrics and experimental parameters relevant to the hyperpolarization and imaging techniques discussed.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Polarization Enhancement | Million-fold | Ratio | Compared to normal magnetic field alignment |
| Polarization Field (Bpol) | 38 - 40 | mT | Magnetic field required for laser-assisted hyperpolarization |
| Clinical MRI Field Strength | 1.5 and 3 | T | Standard magnets used in clinical imaging |
| Experimental MRI Field Strength | 7 | T | Magnet used for signal comparison (Figure 1) |
| Nuclear Spin Coherence Time (T2) | > 90 | s | Achieved in bulk hyperpolarized solid (Reference 2) |
| Current MRI Resolution | Millimeter to Centimeter | Length Scale | Current limitation in clinical practice |
| Target MRI Resolution | Molecular | Length Scale | Goal for quantum-enhanced MRI |
| Diamond Phantom Inner Diameter | 2 | mm | Dimensions used in background suppression experiment |
| Diamond Phantom Outer Diameter | 4.2 | mm | Dimensions used in background suppression experiment |
Key Methodologies
Section titled âKey MethodologiesâThe dual-mode imaging technique relies on precise material engineering and quantum control protocols:
- Material Selection: Utilizing diamond microparticles or nanodiamonds specifically enriched with 13C isotopes to serve as the hyperpolarizable nuclear spin source.
- NV Center Creation: Engineering Nitrogen Vacancy (NV) centersâpoint defects consisting of a substitutional nitrogen atom adjacent to a lattice vacancyâto act as the spin-photon interface.
- Optical Excitation: Shining low-power laser light onto the diamond material to excite the NV centers, aligning their electron spins.
- Spin Transfer: Employing dynamic nuclear polarization (DNP) techniques to transfer the high electron spin polarization from the NV centers to the neighboring 13C nuclear spins.
- Dual Readout: Simultaneously acquiring high-resolution optical images (via NV fluorescence) and high-sensitivity MRI signals (via hyperpolarized 13C spins).
- Scaffolding Development (Future Work): Creating porous diamond structures (âdiamond spongesâ) to facilitate contact and subsequent spin transfer to external analytes (e.g., water, molecular markers) for in vivo applications.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials required to replicate and extend this pioneering research in quantum sensing and enhanced imaging.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the high spin polarization and long coherence times necessary for quantum-enhanced MRI, researchers require highly specialized diamond substrates. 6CCVD offers:
| Material Specification | Application Focus | 6CCVD Capability |
|---|---|---|
| Isotopically Enriched PCD | Bulk hyperpolarization, high-density 13C spin sources, porous scaffolds. | MPCVD growth of Polycrystalline Diamond (PCD) enriched with 99.99% 13C for maximum nuclear spin density. |
| NV-Optimized SCD/PCD | Controlled NV center density for optimal spin-photon coupling. | Custom nitrogen doping during growth or post-growth irradiation/annealing protocols to achieve desired NV concentrations. |
| High-Purity SCD | Fundamental physics, long coherence time (T2) studies, quantum computing. | Single Crystal Diamond (SCD) plates with ultra-low native nitrogen (< 1 ppb) for superior spin coherence properties. |
| Boron-Doped Diamond (BDD) | Electrochemical sensing and alternative hyperpolarization platforms. | Custom BDD films and wafers available for exploring other hyperpolarized solid mechanisms (as mentioned in the paper). |
Customization Potential
Section titled âCustomization PotentialâThe success of this research relies on precise material dimensions and surface quality, areas where 6CCVD excels:
- Custom Dimensions: While the paper used microparticles, 6CCVD can supply large-area diamond wafers up to 125mm (PCD), which can be processed into high-volume microparticles or used as bulk substrates.
- Precision Fabrication: We offer advanced laser cutting and etching services to create custom geometries, such as the specific 2mm/4.2mm ring structures used in the phantom experiments, ensuring high geometric accuracy for microfluidic integration.
- Polishing Excellence: Achieving high-quality surfaces is critical for minimizing spin decoherence. 6CCVD guarantees ultra-smooth surfaces: Ra < 1nm for SCD and Ra < 5nm for inch-size PCD.
- Metalization Services: For integrating diamond sensors into microwave (MW) loops or electronic readout systems (as shown in Figure 2), 6CCVD provides in-house metalization capabilities, including deposition of Au, Pt, Pd, Ti, W, and Cu films.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs technical sales team and in-house PhD material scientists are experts in tailoring MPCVD diamond growth recipes to meet specific quantum and biomedical requirements. We provide consultation on:
- Optimizing 13C enrichment levels versus cost constraints.
- Selecting the appropriate diamond grade (SCD vs. PCD) based on required coherence time and volume.
- Developing custom metalization stacks for integration into complex Quantum Sensing and Dual-Mode Imaging devices.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
His research team focuses on utilizing physical chemistry to develop âquantum-enhancedâ NMR and MRI technologies, pushing past the current resolution and signal limitations.Beyond his research, Dr. Ajoy is very enthusiastic about his students and emphasizes the importance of the contributions made by his graduate and undergraduate researchers.Having become a professor during the SARS-CoV-2 pandemic, he is especially grateful for his students and expressed that the multiple papers published by his lab are due to the hard work of everyone on his team.Sophie Conti, one of Dr. Ajoyâs research assistants who works on the nitrogen vacancy center magnetometry in microfluidics project, said of the Ajoy lab, âIâve really loved working in the Ajoy lab thus far because of the supportive community and amazing opportunities for learning.I think our lab is really unique in that undergraduates are really encouraged and supported by the other lab members to further their own learning and research if it interests them.â In this interview, we explore how the use of diamond microparticles can enhance MRI and optical imaging, resulting in a form of dual imaging that has revolutionary impacts for the fields of medicine, biology, and the physical sciences.