Fluorescence Lifetime Techniques for Label Free Intraoperative Delineation of Tumor-Resection Margins

Transcription

1 Fluorescence Lifetime Techniques for Label Free Intraoperative Delineation of Tumor-Resection Margins Laura Marcu, PhD Professor of Biomedical Engineering and Neurological Surgery University of California Davis EPIC - July 2014 Brain Tumors Head/Neck Tumors

2 The problem Biopsy tissue 1-3 specimens/patient Where should I cut? How much? Did I cut enough? I need to check! Histopathology Lab $$ Frozen section There is no tool to tell the surgeon in real-time where to cut Tumor There is no tool to tell the surgeon in real-time if all tumor was removed Pathologist - $$$$

3 Native Fluorescence Contrast in Biological Tissues (label free) Fluorescent endogenous bio - molecules Structural proteins (tissues): Elastin, Collagens Enzyme co-factors (cell metabolism): NAD(P)H, FAD Amino-acids (proteins): Tryptophan, Tyrosine Lipids Vitamins Porphyrin Pathologic transformation in tissues are associated with biochemical, functional and structural changes of biomolecular complexes in tissues and cells.

4 Fluorescence Measurements Light Source (laser) Fluorescence Detection Module Time-Resolved Fluorescence Spectroscopy (TRFS) Fluorescence Intensity / Spectrum Φ = Γ/ (Γ+k) E λ(i) = hν(i) Lifetime τ =1/(Γ+k) Fang et al, Rev Sci Instrum (2004)

5 Why Fluorescence Lifetime Measurements? Lifetimes can provide effective means of discrimination among fluorophores fluorophores with overlapping emission spectra but with different fluorescence decay times can be discriminated Lifetimes are minimally affected by the variation of excitation intensity or other factors that nonlinearly affect the fluorescence intensity endogenous absorbers, photobleaching, changes in excitation-collection geometry, etc.

6 Fluorescence Lifetime Systems Used in Clinical Settings Time-Resolved Fluorescence Spectroscopy (TRFS) Fluorescence Lifetime Imaging Microscopy (FLIM) Computational models for recovery of fluorescence decay Point-spectroscopy Pulse sampling Wide-field microscopy Time-gated detection IRF expansion on the Laguerre basis Model-free Fast Multiple parameters System Identification & Classification

7 Intraoperative TRFS: Brain Tumor Tumor cavity (resection margins) Cortex surface Normal White Matter Low Grade Glioma TRFS of Gliomas L. Marcu et al. Photobiol. Photochem, 2004 W.H. Yong et al. Front. Biosciences, 2006 P.V. Butte et al. JBO, 2010 P.V. Butte et al. Neuroimage, 2011

8 Fluorophores in normal brain and brain tumor Emission spectra Fluorescence lifetime Fluorophore Excitation (nm) Emission (nm) Lifetime (ns) Pyridoxamine Phosphate? NADH Glutamate Decarboxylase? Collagen

9 TRFS: Gliomas Classification (35 patients, 73 point measurements) Low Grade Glioma (LGG): Oligodendoglioma Oligostocytoma Diffuse astrocytoma Fluorescence Spectroscopy NC NW LGG HGG High Grade Glioma (HGG): Glioblastomas Anaplastic oligodendroglioma Sens. (%) Spec. (%) NC (n = 33) NWM (n = 13) LGG (n = 9) HGG (n = 18) safety of resection = high specificity Butte et al. Neuroimage, 2011 Butte et al. Journal of Biomedical Optics, 2010

10 Intraoperative FLIM Glioma delineation (10 patients) Sun et al. Journal of Biomedical Optics (2010), 2010 Normal λ em = 460±25 nm Tumor

11 TRFS of Head and Heck Cancer Example : Vocal Cord Normal 100µm Tumor 100µm Otolaryngology Head and Neck Surgery, ~400 nm 440~470 nm Lifetime (ns) LEC-2 Lifetime (ns) LEC-2 Normal (n=7) 1.69± ± ± ±0.004 Cancer (n=6) 1.29± ± ± ±0.003 P-value

12 FLIM Head and Neck Cancer Intensity Lifetime Microscopy and Microanalysis, patients Sensitivity 83% Specificity: 97%

13 Is the problem solved? NO! What do we need? Brain tumors 60 patients Head and Neck tumors 20 patients Mathematical models for fast and accurate analysis of fluorescence data Faster data acquisition / analysis 30 seconds less than 1 second Clinical data to demonstrate the feasibility of the technique in a variety of clinical situations New ways to validate the optical data histopathology challenge

14 DM: Dichroic mirror BP: Bandpass filter Multispectral TRFS (ms-trfs): Point Scanning Imaging 370 nm DM 425 nm DM 515 nm DM 610 nm DM 630/50 nm BP Sample Pulsed UV Laser 355 nm, 80 ps Digital Oscilloscope 40G Sample/sec Ref: Optics Letters, 2008 Review of Scientific Instruments, /40 nm BP 460/50 nm BP 550/50 nm BP 10 m 1 m Gated MCP-PMT Pre-amplifier Bandwidth 2.5GHz 19 m Rise time 0.27 ns 28 m 4 Ch1 Ch2 Ch3 Ch4 5 3 Faster tissue sampling through acquiring multiple 5 2 colors and lifetimes from 5 each single laser pulse! Point Measurement 1D Line Scan 390 nm 2D FLIM Image

15 Initial Proof-of-Concept ms-trfs as a tool for brain tumor diagnosis Surgical interventions Streotactic biopsy ms-trfs as a diagnostic tool in robotic surgery Head and neck tumors

16 Surgical Interventions Simulation Agar + Coumarin 120 Real-time display of fluorescence characteristics Fiberoptic 400 µm core 0.22 NA 710 µm stainless steel tube White light UV light Fluorescent bead: Coumarin 1 - tumor

17 Stereotactic Biopsy Simulation Real-time display of brain phantom fluorescence characteristics icestereotactic.htm html (MONTERIS)

18 Intraoperative assessment of the head & neck cancer Trans Oral Robotic Surgery Base of tongue resection Collaboration with Dr. Gregory Farwell (UC Davis) and Intuitive Surgical

19 Real-time ms-trfs integrated with da Vinci surgical robot ns

20 Conclusion: ms-trfs based diagnostic Flexible implementation: from point spectroscopy to scanning Nondestructive no tissue is removed Label free no need for administration of contrast agents Real time tissue diagnosis during interventions

21 Acknowledgement National Institutes of Health Grants: R01-HL6737, R21-EB3628, R42-CA117268, R21-RR NIH Clinical Translation Science Center (CTSC) Comprehensive Cancer Center UC Davis Boston Scientific Corporation Intuitive Surgical Inc. UCOP PC Biophotonics Lab Diego Yankelevich, PhD Julien Bec Jennifer Phipps, PhD Dimitris Gorpas, PhD Jing Liu, PhD Hussain Fatakdawala Nisa Hatami Matthew Yee Adrian Lam Matthew Lam Fei Fei Zhou Alumni Javier Jo, PhD Qiyin Fang, PhD T. Papaionnou, PhD Jesung Park, PhD Pramod Butte, PhD Yinghua Sun, PhD Yang Sun, PhD Hongtao Xie, PhD Collaborators Daniel S. Elson, PhD (ICL) William Ferrier, VMD (UCD) Keith L. Black, MD (CSMC) Jeffrey Southard, MD (UCD) Gregory Farwell, MD (UCD) Rudy Schrot, MD (UCD) Jonathan Sorger (Intuitive Surgical)