Nano-optical Imaging using Scattering Scanning Near-field Optical Microscopy
Meltem Izzetoglu Optical Brain Imaging Team
description
Transcript of Meltem Izzetoglu Optical Brain Imaging Team
Meltem IzzetogluOptical Brain Imaging Team
School of Biomedical Engineering, Science & Health Systems, Drexel University
Philadelphia, PA
Joint Studies with Britton Chance and His Team
Adult and Pediatric Applications of Optical Brain Imaging
June 3 & 4, 2011Philadelphia PA, USA
Britton Chance: Life, Times, & Legacy
Symposium and Workshop
Outline
Early joint studies with Dr. Chance and Optical Brain Imaging team at Drexel University Signal processing algorithm developments and various applications First prototype pediatric system development, testing and
applications
Influence of the early studies in the current algorithm developments, system designs and applications Algorithms for motion artifact removal and applications Evolution of the pediatric system to current wireless version and
applications Evolution of the phantom model and tests conducted
Algorithm developments and applications
Single trial evoked hemodynamic response extraction (Izzetoglu et al, 2005)
Anagram Protocol (a linguistic problem solving study of graded difficulty)
Model Fitting for Single Trial Hemodynamic Response Detectiono Oxygenation data (Oxy) is modeled as the summation of each single trial hemodynamic
functions (HF) related to stimulus:
o Each hemodynamic function is represented by a gamma function :
o Unknown parameters of HFs are found by minimizing the mean square error between Oxy data and the model by using least mean squares curve fitting:
N
iihfOxy
1
i i iti i ihf At e
AmplitudeFWHM
Time to Peak
2
1,,)(min
,
N
iiBA
hfOxyiiii
fNIR Sensor
Algorithm developments and applications Single trial evoked hemodynamic response extraction Results on 14 subject Anagram data collected at Dr. Chance’s Laboratory
Oxygenation rise times follow the same pattern as the behavioral response times (Pearson’s r = 0.92).
The rise time and maximum amplitude of oxygenation increase as the difficulty level of the anagram solutions increase
Av e rage d Re sponse and Rise Time s of the Sing le Tr ia l
He mo dyn amic Re spon se Estimate s
0.000
1.000
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3L-1st Set 4L-1st Set 5L 4L-2nd Set 3L-2nd Set
Ave Resp TAve RiseT
Av e ra g e d M a x im u m Am p litu d e o f th e S in g le Tir a l H e m o d yn a m ic R e s p o n s e Es tim ate s
0 .0 0 0
0 .0 5 0
0 .1 0 0
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3L -1 s t Se t 4 L -1 s t Se t 5 L 4L -2 nd Se t 3 L -2n d Se t
All Anagram Data: Correlation Coefficient=0.92; Slope=1.17
0.0001.0002.0003.0004.0005.0006.0007.0008.0009.000
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0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000Response Time
Rise
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Algorithm developments and applications Arithmetic and Geometric Mathematical Problem Solving Study
Higher bilateral oxygenation is observed during tasks with higher difficulty compared to control tasks with less difficulty.
fNIR findings of are inline with fMRI literature that indicates higher prefrontal cortex activation during problem solving
fNIR Sensor
Geometric Control Tangram Puzzle
Arithmetic Control Arithmetic Tasks
First prototype pediatric system developmentOne light source (with two built in LEDs at 730 and 850nm wavelengths) two detector wired pediatric system (Alper Bozkurt, Master’s thesis,2004)
Testing on phantoms and pediatric applicationsTesting on liquid phantom in Dr. Chance’s Laboratory (Bozkurt et al, 2005)
Pediatric Application - Hearing test (Rosen et al, 2005) NIRS measurements were obtained for 1 minute before, during, and 1 minutes
after NJ State mandated hearing screen evaluation from two healthy newborns.
Influence of the early studies in algorithm developments, system designs
and applications
Evolution of Signal Processing Algorithms and Applications
Motion Artifact Removal Adaptive, Wiener and Kalman Filters (Izzetoglu et al. 2005, 2010)
ICA/PCA based algorithm used in the operating room (Kurtulus Izzetoglu, Ph.D. thesis, 2008)
S-MAR used in BCI Settings and FAA Applications (Hasan Ayaz, Ph.D. thesis, 2010)
16-channel fNIR sensor
Evolution of the pediatric system to current wireless version with application to pediatric pain assessment
Wireless pediatric system
Pediatric pain assessment (Izzetoglu et al, 2010)
5 healthy term infants
2 heel-stick blood draws, 2 intra-muscular vaccination, 1 circumcision and vaccination.
HbO2 Hb
Texas Instrument’s ZigBee cc2430 System-on-Chip
60 feet wireless communication in open space 30 feet wireless communication in lab
environment Battery performance of 3 continuous hours
Evolution of the phantom model
Multi Layer Dynamic Liquid Phantom adult human head model with skin, skull, CSF and brain layers Dynamic changes in Hb and HbO2 can be established Allows measurement from skin and brain sides Targets can be placed within the brain layer
Tests conducted effects of superficial layers at different source detector separations
Hematoma and edema tests
1700 1800 1900 2000 2100 2200 2300 2400 2500 2600
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20Hematoma Test using new probe with 960nm
time (sec)
HbHbO2WaterBV
Deoxygenation Oxygenation
Hematoma
Hematoma
Thank You________________________________________________________
Meltem Izzetoglu
3141 Chestnut StPhiladelphia PA 19104Tel: 215-895-1988Fax: 215-895-4983Email: [email protected]
www.biomed.drexel.edu/fnir