Quantum Orbital Resonance Spectroscopy

Transcription

1 Quantum Orbital Resonance Spectroscopy Philips Research: Remus Albu, Dan Elgort, Khalid Shahzad, Ramon Erkamp, Jean-Luc Robert, Shiwei Zhou UC Berkeley: David Attwood, Anne Sakdinawat NYU: David Grier, Tycho Sleator, Lisa Dixon November 18, 2010

2 Quantum Orbital Resonance Spectroscopy New modality for neurodiagnostic imaging and spectroscopy Philips Research N.A., November 18,

3 MRI and MRS MRI Conventional Magnetic Resonance Imaging (MRI) measures the spatial distribution of hydrogen protons in water. MRS Magnetic Resonance Spectroscopy (MRS) uses long measurement times and/or stronger magnetic fields to distinguish between protons in water and protons in different atomic or molecular species. Philips Research N.A., November 18,

4 NAA/Cre MRS for TBI Mild/moderate TBI can look normal on CT and MRI Diffuse axonal injury is a marker of TBI and visible in MRS N-acetylaspartate (NAA) decreases due to neuronal loss Choline (Cho) increases due to membrane repair, inflammation, or demyelination Lactate increases due to proliferation of astrocytes and glial cells Creatine (Cre) generally remains constant and enables normalization R Aupperle, et al. Hoglund Brain Imaging Cntr, U of Kansas Med Severely disabled No disability Proton MRS in TBI, Brain (2000) 123: Disability Rating Scale Philips Research N.A., November 18,

5 % polarization of 1H Limits of Conventional MRI and MRS Weak signal, ~5 protons per million Low sensitivity Low spatial resolution Long imaging times Quantum Orbital Resonance Spectroscopy Theory (Zeeman Splitting) Current SOA Superconducting magnets required Not portable Expensive ($1 to $3 million) Magnetic Field (T) Philips Research N.A., November 18,

6 Hyperpolarized MR Instead of powerful magnets, use alternate approach to align nuclei Currently, three methods exist: Dynamic Nuclear Polarization (DNP) Spin-exchange optical pumping (SEOP) Para-hydrogen induced polarization (PHIP) Up to 5 orders of magnitude increased MR Signal No method can directly hyperpolarize living tissue alanine bicarbonate pre post Pulmonary Diagnostic Exams (SEOP) Prostate Cancer Diagnosis (DNP) Imaging Myocardial Infarction (DNP) Philips Research N.A., November 18,

7 The Problem and Solution Since conventional MRI requires powerful magnets and hyperpolarized MRI cannot hyperpolarize living tissue MRI cannot be use to diagnose TBI on the battlefield Solution: Quantum Orbital Resonance Spectroscopy Philips Research N.A., November 18,

8 Quantum Orbital Resonance Spectroscopy Ultra-sensitive MR Spectroscopy Micron-scale spatial resolution Non-invasive measurements of brain tissue Portable device -- MRS without super conducting magnets X-Ray OAM generator and spatial scanner X-ray Beam Scanner Transmission Phase Hologram 0x,0y Scanner Quarter Wave Concave Mirrors Polarizer Illumination Cone Hyperpolarization Locus Surface Diagnose traumatic brain injury (TBI) and other disorders that affect brain chemistry Ultra-Soft X-ray Source Beam Colimator and X-ray La filter Spatial Filter Parabolic Mirror ` Focal Point Parabolic Mirror B 0 and RF receiving coils Optical aperture Electronic Control System Patient Skull Brain Matter Under Test Philips Research N.A., November 18,

9 Proposed QORS Device Characteristics Method of polarization Conventional MRI High magnetic field Functional MRI High magnetic field QORS Light with OAM X-Ray OAM generator and spatial scanner X-ray Beam Scanner Transmission Phase Hologram 0x,0y Scanner Quarter Wave Concave Mirrors Polarizer Illumination Cone Hyperpolarization Locus Surface Encoding of Spatial Information Encoded using magnetic field gradients Encoded using magnetic field gradients Hyperpolarized signal is restricted to focal point of beam Volumetric Volumetric OAM beam is scanned in 2D; 3D in slices Ultra-Soft X-ray Source Beam Colimator and X-ray La filter Spatial Filter Parabolic Mirror Parabolic Mirror ` Focal Point Contrast Density of 1 H in water Changes in blood supply due to neural activity Density of 1H in blood Use additional nuclear species (e.g. 13 C ) as new window to molecule B 0 and RF receiving coils Electronic Control System Optical aperture Patient Skull Brain Matter Under Test Measurement time for point sec Measurement 30min 30min 10min / <1min time for image Spatial Resolution mm 2 mm 2 m 2 / mm 2 ** Develop small, inexpensive and field-deployable system. Use commercially available compact X-ray source (size ~5cm) X-ray optics and MR detection system can be small Estimated cost to manufacture ~$100k **Using an array of 1 µm beams Imaging with QORS would be a significant advancement over MRI. Philips Research N.A., November 18,

10 Photonic Orbital Angular Momentum (OAM) p k S 1,0,1 L l l.., n, n 1,..,0,.., n, n 1,.. P Photon linear momentum S Photon spin momentum L Photon Orbital Angular Momentum (OAM) : a measure of light rotation around the propagation direction Experimental verification of the existence of light endowed with OAM Philips theoretical prediction and first experimental verification of hyperpolarization with light endowed with OAM 2015? - Hyperpolarized MRI and MRS with a portable device Philips Research N.A., November 18,

11 Hyperpolarization h KEY: JM Je JN N e N e 1. The photon exerts a torque on the molecule, rotating it along the propagation axis of incident light. 2. The electron spin orbital becomes saturated (i.e., all the electron spins are aligned along the propagation axis). 3. Via hyperfine coupling and spin-spin interactions between nuclei in the molecule, the molecular angular momentum is transferred to the nuclear spins, aligning them along the propagation axis. 4. Via hyperfine interaction between the electrons and the nucleus, the nuclear magnetic moment is oriented along the direction of light propagation A high degree of nuclear polarization is achieved through a series of reinforcing interactions. Philips Research N.A., November 18,

12 Photons with OAM to Rotate Molecules Predicted by many theoretical papers Hyperpolarization efficiency is strongly related to molecular rotation We evaluate a method for assessing molecular rotation imparted by photons with OAM Philips Research N.A., November 18,

13 Photon OAM interactions - Theory Schrodinger equations applied to the Hamiltonian of the electromagnetic wave potential vector interacting with fermions (spin ½ distinguishable particles with mass, charge, linear momentum, spin): n mol H t p A r t p A r t s A r t n1 2mn c c 2mnc V V V 1 e,,, n en en n n n n n n n NN NE EE probabilities of transitions between states are given by the Fermi golden rule: 2 2 T f H i M 2 2 f i r r f i p n, s n, m n,e n A(r n,t) T fi r V NN V NE V EE particle n linear momentum, spin, mass, charge light potential vector at point (r n,t) Transition probability from state i > to f> Final density of states total energy for nucleon-nucleon, electron-nucleon and electron-electron interactions Philips Research N.A., November 18,

14 Transitions matrix coefficients I il n M n, f i, l,0 in f fl, p rn e i rn 2,0 n II l M i n, f i, l,0 n l f i f RnFl,0 r n i w 0 R n III M i n, f i, l, p nk f Fl, p r n sn 1 i F l, p r n IV n f i l p n sn 1z Rn II,,, n, f i, l, p n, 1z M i l f M L i f i F r Philips Research N.A., November 18,

15 Transitions matrix coefficients 2 Fl,0 r n II M i n, f i, l,0 n l f i w 0 Rn For dipolar molecules with zero spin, no chirality, random distribution of the rotational direction our model predicts an increase of the NMR signal proportional to the square of the photon OAM value. 2 2 II T M r ~ C l f i n, f i, l,0 2 Philips Research N.A., November 18,

16 Photons with OAM to Polarize Nuclei Experimental Setup mW 488nm continuous light Computer Generated Hologram 0.35T permanent magnet Customized NMR 1l fluid sample ~1.. 20m diameter focal spot Philips Research N.A., November 18,

17 Photons with OAM to Polarize Nuclei Experimental Setup mW 488nm continuous light Computer Generated Hologram 0.35T permanent magnet Customized NMR 1l fluid sample ~1.. 20m diameter focal spot Philips Research N.A., November 18,

18 Experimental Results: NMR Signal vs. OAM Experimental measurements precisely match the relationship predicted by our theoretical model Philips Research N.A., November 18,

19 Confirmation of Results A duplicate experimental setup has been implemented by our program collaborators at NYU Goal is to duplicate and confirm the initial NMR findings Additional work at NYU will characterize the transfer of OAM from visible light to macroscopic particles 1.5 m Polystyrene spheres 20 mw, OAM = m Philips Research N.A., November 18,

20 Visible Light and X-rays A device for measuring TBI must hyperpolarize white matter ~5 cm below the surface of the head Visible light will only penetrate ~5mm into the head X-rays at ~20keV are required to reach the target anatomy Electromagnetic radiation at any wavelength can be endowed with OAM Refractive optics cannot be used with X-rays X-rays and visible light interact with matter differently Philips Research N.A., November 18,

21 OAM X-rays Interaction with Molecules and Nuclei 9keV X-rays change the nuclear polarization (multipolar transition) Orbital interactions (Xrays absorption with energies less than the ionization limit) induce polarization dichroism Philips Research N.A., November 18,

22 X-ray OAM generation: Spiral Zone plates Zone plates designed and produced by Dr. Sakdinawat/UCB OAM charges 10,20,40 for 20keV Outermost zone widths are 100 nm Au height: ~ 2m Unprecedented form factor ~20:1 Philips Research N.A., November 18,

23 QORS X-ray Qualification QORS analysis and qualification will use Argonne National Labs ALS Synchrotron ID34 20keV X-ray beam line and X-ray analysis instrumentation Diffraction grating & Fresnel plate focal length ~75mm 20keV X-ray OAM beam waist ~100nm Philips Research N.A., November 18,

24 DARPA Program Phase I Plan (currently in month 12 of 18) Validate the QORS concept with visible light Characterize the physics using visible light Perform QORS with X-rays Demonstrate X-ray QORS with clinically relevant penetration depths Estimate X-ray dose and safety implications Phase II Plan (18 months) In vivo evaluation of technique with increased measurement volume Phase III Plan (18 months) Build portable prototype Philips Research N.A., November 18,

25 Phase I Progress To Date OAM can be transferred to matter and influence molecular rotation Increasing levels of OAM will generate an increased NMR signal The increase in NMR signal due to OAM agrees with theory Future NMR experiments will enable quantitative measurements of the degree of nuclear hyperpolarizaton Future X-ray OAM experiments will enable confirmation of theoretical predictions regarding NMR with OAM X-ray photons Philips Research N.A., November 18,

26 Future Potential Portable devices for MR imaging and spectroscopy MR measurements of nuclei other than Hydrogen 13 C, 17 O, 31 P, 23 N Inexpensive QORS scanners tailored for specific anatomy GP Practices, Medical Centers in developing counties, sports medicine New chemical diagnostic tool for medical specialties including neurology, oncology, and cardiology (e.g. QORS In Vivo Biopsy) Powerful benchtop NMR spectroscopy systems Philips Research N.A., November 18,

27 Acknowledgements We would like to thank the DARPA DSO and our program manager: Dr. Matt Goodman and his SETA support team: Dr. Lindsey Hillesheim Mr. Michael Armillay Philips Research N.A., November 18,

28 Philips Research N.A., November 18, 2010

29 QORS Versus DNP Operating Temperature Polarization Mechanics Concept Validation Allowable Target Materials Hyperpolarize living tissue DNP solid state polarization Microwaves saturate electrons at ultra-low temp and high magnetic field, transfer to nuclear polarization proven principle, 50% polarization achieved routinely special chemistry, electron donor, filtering required No Photonic OAM fluid phase at room temperature Orbital angular momentum (OAM) of photons transferred to molecules, converted to magnetic moment early experimental phase, proof of concept in small sample volume no specific chemistry / no catalyst, easier approval Yes Portable device No Yes Philips Research N.A., November 18,

30 X-rays scattering coefficient The scattering is higher at lower wavelengths. Philips Research N.A., November 18,

31 X-rays photo ionization effects New theoretical model (Jean Luc Robert Philips) refines the photon OAM interaction with molecules modeled as dipoles with rotational modes Model gives the probability of interaction of the molecule with photon s OAM: ap l l w0 DZ dipole size Photon OAM charge scalar Photon wavelength scalar in vacuum OAM beam waist sample thickness As the wavelength decreases, w 0 (beam waist) decreases and the probability of interaction increases At ionization a p (the dipole size) increases, therefore the probability of interaction increases with a p 4. The ionized state has a very short lifetime Philips Research N.A., November 18, 2010

32 Photoionization with OAM Recent paper (thanks to Anne) shows an increase of the amplitude of the interaction of the OAM with the orbital's, while photons endowed with OAM are energetic enough to produce ionization. This confirms that X-rays endowed with OAM produce a stronger OAM transfer to the molecule, i.e. a stronger hyerpolarization than observed by visible light Philips Research N.A., November 18,

33 NMR Experiments Experiment flow and data processing: 1. Measure the time delay corresponding to the null point of blocked light 2. For the same time delay, repeat for light ON, and different OAM values 3. Measure the average peak integral of the NMR line 4. Measure the power and the radius of the OAM beam. Philips Research N.A., November 18,

34 Beam Diameter / Power at sample vs. OAM CW 488nm laser line Philips LCoS panel (20m pixels) Philips Research N.A., November 18,