Biomedical Imaging

1. Biomedical Imaging

2. Molecular Imaging - Biomarker Localization Molecular Contrast Agent Image Beacon Target Protein Biological Targeting Molecular Image showing concentration of target protein

3. Ultrasound Imaging

4. Why Ultrasound for Molecular Imaging? PET/CT MRI Ultrasound • Low cost • No radiation • Non-invasive • Highly portable • Real time imaging

5. Microbubble (1 mm diameter) Link Over-expressed specific cellular receptor Antibody to specific cellular receptor Targeted Ultrasound Contrast Agent

6. Light & Sound at Molecular Scale • Molecular imaging combining ultrasonics with photoacoustics

7. 0 100 ns Photoacoustic Imaging Optical contrast at ultrasound resolution Reasonably large penetration depth (one way) 50um black bead Pulsed Laser Ultrasound detector

9. In-vivo PA imaging Photoacoustic image superimposed on ultrasonic image

10. Link Over-expressed specific cellular receptor Wavelength-dependent Optical absorber Antibody to specific cellular receptor Targeted Photoacoustic Contrast Agent

11. Targeted Photoacoustic Contrast Agent Endocytosis

12. Au Nanorods - Absorption Selectivity Prahl S, Oregon Medical Laser Center

13. IVC Aorta Right Renal Vein Left Renal Vein Surfactant (CTAB) Vascular Injury Cell Anti ICAM-1 ICAM-1 PAA ICAM-1 overexpressed Cell Bioconjugated Gold Nanorods Ultrasound-Photoacoustic Molecular Image Molecular PA image overlaid on top of US Image clearly showing site of vascular inflammation Potential Impact: US-PA imaging can guide over 1.5 M vascular interventions annually

14. US/PA Molecular Imaging Before injection After injection Pai-Chi Li - NTU

15. Molecular Therapy PA Temp – In vivo 20 x 10.5 mm 25 oC Temperature change 1 oC Stas Emelianov – UT-Austin

16. Are these signals nanoparticles or background ? PA Molecular Imaging: A Problem Tumor Before injection After injection

17. PA Imaging: A Problem Fundamental detection limit Tissue background PA Imaging: A Problem Saturation PA Signal Number of Particles / Voxel

18. Coupled Particles Coupled States Coupled States Coupled Agents: A Solution ?

19. Coupled States • Absorption modulation with light • Transient absorption vs. ground-state absorption • Differential-absorption photoacoustic (DAPA) imaging

20. Coupled States: Principle

21. PtOEP • Phosphorescence lifetime: hundreds of ns ~ tens of µs • Can be pumped at 532 nm • Can be used to estimate oxygen concentration with PA measurement

22. Experimental Setup

23. Proof of Concept

24. Imaging -43 dB

25. Transient Absorption vs. Pump Excitation probability

26. Excitation Probability vs. Depth (3 cm, 1− e−1) Oxyphor G2: σa,pmp = 1.9×10−16 cm2 at 633 nm

27. Conclusions: Coupled States • DAPA imaging can enhance PA contrast specificity by suppressing undesired background objects • DAPA imaging has the potential to provide sufficient imaging depths for biomedical applications

28. Coupled Particles Coupled Particles Coupled States Coupled Agents: A Solution ?

29. Background Tissue MNPs Coupled Magnetic Nanoparticles

30. Background Tissue MNPs Magnetic Field Coupled Magnetic Nanoparticles

31. Background Tissue MNPs Coupled Magnetic Nanoparticles

32. Differential PA Imaging • Image object with magnetic field off • Image object with magnetic field on • Use “motion” processing to differentiate regions of the image moving coherently with magnetic field

33. Differential PA Imaging Motion filtering mmPA imaging PA imaging Signal from coupled agent Signal from coupled agent Localized background Diffuse background

34. MNP-AU Core-Shell Agents Biomimetic synthesis of MNP-Au core-shell NPs using polypeptide as a template for directed Au nucleation and growth (Xiaohu Gao – BioE)

35. MNP-AU Core-Shell Agents • Core with finite magnetization • Shell with tunable optical absorption

36. MNP-AU Core-Shell Agents

37. Proof of Principle Pulsed laser UT water Preamplifier PVA FPGA GMNPs MNPs Rods Digitizer Electromagnet XY stage Function generator Current amplifier

38. Conventional Photoacoustic Image

39. Magnetic Manipulation

40. g a PA image sequence mmPA image Motion tracking b Pixel-wise displacement f Weighting image c d Max. V+ e Max. V- Displacement fitting

41. Motion-enhanced PA Imaging Greater than 40 dB suppression

42. Conclusions: Coupled Particles • Developed core-shell nanoparticle with magnetic core and gold shell exhibiting high absorption in the NIR (Gao) • Nanoparticles can be manipulated with external magnetic field • Motion processing can dramatically reduce background PA signal

43. Challenge for a Potential Application What if the initial concentration of a targeted cell type circulating in the vasculature is too low to be detected and the PA background signal from blood overwhelms the PA signal from the targeted cells?

44. Fibre Laser pulses Magnet Photoacoustic signals Skin Transducer Blood vessel Acoustic waves Captured CTCs In vivo magnetic enrichment and multiplex photoacoustic detection of circulating tumour cells Ekaterina I. Galanzha1,2, Evgeny V. Shashkov1,3, Thomas Kelly1,4, Jin-Woo Kim5, Lily Yang6 and Vladimir P. Zharov1* 1Phillips Classic Laser and Nanomedicine Laboratories, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA 2Saratov State University, Institute of Optics and Biophotonics, Saratov 410012, Russia 3Prokhorov General Physics Institute, Moscow 119991, Russia 4Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA 5Department of Biological and Agricultural Engineering and Institute for Nanoscale Materials Science and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA 6Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA *e-mail: zharovvladimirp@uams.edu Nature Nanotechnology, vol. 4, pp 855- 860 (2009)

45. Solution for a Potential Application?

46. Contrast-enhanced Photoacoustic Imaging mm mm Congxian Jia1, Jinjun Xia1, Ivan M Pelivanov1,2, Sheng-Wen Huang1, Yongdong Jin1, Chi Hyung Seo1, Lingyun Huang1, Janet F Eary1, Xiaohu Gao1, and Matthew O’Donnell1 1University of Washington, USA 2Moscow State University, Russian Federation

47. Experimental Setup Pulsed laser Probe water + milk VeraSonics PVA MNP Dual Magnets tube XY stage Computer FPGA

48. Accumulating PA Signal

49. Experimental Setup Pulsed laser Probe water + milk VeraSonics PVA MNP Dual Magnets tube XY stage Computer FPGA

50. Experimental Setup Pulsed laser Probe water + milk VeraSonics PVA MNP Dual Magnets tube XY stage Computer FPGA