Get documents about "Biomedical Imaging
Document Sample
Biomedical Imaging 2
Class 1 – Introduction
01/22/08
BMI2 SS08 – Class 1 “Introduction” Slide 1
Course instructor
Dr. Harry L. Graber
Research Assistant Professor of Pathology / SUNY Downstate Medical
Center / Room BSB 4-132, (718) 270-1286 /
harry.graber@downstate.edu
A.B., Chemistry 1983, Washington University,
St. Louis, MO
Ph.D., Physiology and Biophysics 1998, SUNY Health Science
Center, Brooklyn, NY
Postdoctoral Fellow 1998, SUNY Downstate
Medical Center
Res. Asst. Professor 2001, SUNY Downstate
Medical Center
Research Focus: Optical Tomography - Image Reconstruction and
Signal Analysis
BMI2 SS08 – Class 1 “Introduction” Slide 2
Lecture hours / locations, credits
• Classes
– Location: SUNY DMC HSEB 8J
– Hours: Tuesday, 10:00 AM to 1:00 PM
• Credits
– Classroom Participation: 15%
– Homework: 20%
– Exam1: 30%
– Exam2: 35%
BMI2 SS08 – Class 1 “Introduction” Slide 3
Course materials
• No specific textbook
• Topic-specific readings (research papers, review papers, scientific
magazine articles, internet pages) will be provided as needed
• Lecture notes and copies of assigned readings will be posted for
download at http://OTG.downstate.edu/download.htm
BMI2 SS08 – Class 1 “Introduction” Slide 4
What is This Course About?
BMI2 SS08 – Class 1 “Introduction” Slide 5
Imaging Modalities Covered in BMI1
• X-ray Projection Radiography
• X-ray Computed Tomography
• Nuclear Imaging
– Planar Scintigraphy
– Positron Emission Tomography
– Single Photon Emission Computed Tomography
• Ultrasound
• Magnetic Resonance Imaging
– Structural MRI (anatomy)
BMI2 SS08 – Class 1 “Introduction” Slide 6
Imaging Modalities Covered in BMI1
• In brief, structural imaging (SI) techniques
– With one significant exception
BMI2 SS08 – Class 1 “Introduction” Slide 7
Imaging Modalities Covered in BMI2
• Functional imaging (FI) methods
– Diffuse Optical Tomography
– Optical Coherence Tomography
– Functional MRI (fMRI)
– Electroencephalographic Imaging
– Magnetoencephalography
– Combined, or multi-mode, imaging
• But what does “functional” mean?
BMI2 SS08 – Class 1 “Introduction” Slide 8
Meaning of “functional” is context-specific
• Always involves examination of what tissue is doing
– But how this examination is carried out is different for different
methods
– In some cases, functional imaging just means producing as
many structural images as you can, as fast as you can
• Example: functional x-ray CT
– Same goes for some kinds of functional ultrasound
• What about MRI?
BMI2 SS08 – Class 1 “Introduction” Slide 9
Varieties of fMRI
• Diffusion-weighted Imaging
• Perfusion Imaging
– Contrast-agent-based
– Magnetic Resonance Angiography / Venography
• Saturation-based
• Bipolar-gradient-based
– Arterial Spin Labeling
• Diffusion Tensor Imaging
• Magnetic Susceptibility Imaging
– Contrast-agent-based
– Blood Oxygen Level Dependent
BMI2 SS08 – Class 1 “Introduction” Slide 10
Some Modalities Are Inherently Functional
• A: Abdominal x-ray CT image (structural/anatomical)
• B: PET image of same tissue section (functional)
• C: Co-registered x-ray CT and PET images
BMI2 SS08 – Class 1 “Introduction” Slide 11
FI Usually Is More “Indirect” than SI
• Direct imaging = (essentially) no math needed
– Laws of physics do the work
– e.g., Project an image onto a piece of film with a lens
• Indirect imaging = lots of math required
– Computers used to process the measurement data and
reconstruct images
• “More indirect” means that additional, post-
reconstruction operations are needed
– Usually involves some type of comparison among images
from data collected at different times
BMI2 SS08 – Class 1 “Introduction” Slide 12
Instructional Emphasis
• Image contrast mechanisms
– How is energy interacting with matter (i.e., tissue)
– What is the image a picture of?
• Biological/clinical motivation
– Why do we care about the parameter(s) in the image?
– How is having this image going to help us?
• How will it affect the treatment our patient is getting?
• Data analysis “from soup to nuts”
– Pre-processing operations
– Image reconstruction
– Post-processing operations
– “Post-post-” processing operations
BMI2 SS08 – Class 1 “Introduction” Slide 13
Tentative Syllabus
1) Introduction; diffuse optical tomography (DOT)
01/22
2) DOT
01/29
3) Image post-processing & time-series analysis, Pt. 1
02/05
4) Optical coherence tomography (OCT)
02/12
5) fMRI – diffusion-weighted, perfusion
02/19
6) fMRI – perfusion
02/26
7) Exam1
03/04
8) fMRI – BOLD
03/11
9) OSA Conference, no class
03/18
10) Image post-processing & time-series analysis, Pt. 2
03/25
11) fMRI – diffusion-tensor imaging
04/01
12) EEG/MEG principles
04/08
13) EEG imaging
04/15
14) MEG imaging
04/22
15) DOT’s “relatives”: fluorescence OT, bioluminescence OT,
04/29
correlation tomography, optoacoustic tomography
16) 05/06 Exam2
17) 05/13 Wrap-up
BMI2 SS08 – Class 1 “Introduction” Slide 14
Electromagnetic spectrum
BMI2 SS08 – Class 1 “Introduction” Slide 15
Diffuse Optical tomography (DOT)
• Year discovered: ~1988
• Form of radiation: Near-infrared light (non-
ionizing)
• Energy / wavelength of radiation: ~1 eV / 600–1000 nm
• Imaging principle: Interaction (absorption, elastic
scattering) of light w/ tissue
• Imaging volume: ~103 cm3
• Resolution: Low (~1cm)
• Applications: Perfusion, functional imaging
BMI2 SS08 – Class 1 “Introduction” Slide 16
DOT and CT: Superficial Similarities, Essential
Differences
• Generation: x-ray tube Source
• Detection: Detector arrays (ion.-chambers,
scint. + photodiode)
• Computer reconstruction of 2D slices/ 3D
volumetric images
Object
Detector
BMI2 SS08 – Class 1 “Introduction” Slide 17
Principles of DOT
• Scattering dominated
• Limited penetration depth (~cm), low
res. (mm-cm)
• Economic, functional (hemodynamics)
screen / detector
screen / detector
light source
light source
light source detector
D
S
obstacle (absorber) obstacle (absorber)
Clear medium Scattering medium
S
D D
106
Molar extinction coeff. [cm M ]
-1
-1
105
104 Hb
103
HbO2 D D
2
10
400 500 600 700 800 900 1000
BMI2 SS08 – Class 1 “Introduction” Slide 18
Wavelength [nm]
DOT Instrumentation
Source / Detector 1
Detector 2
2-3 cm Detector 3
Scalp
Bone
CSF
Cortex
BMI2 SS08 – Class 1 “Introduction” Slide 19
DOT Applications
Brain SPECT
Breast
Arm
BMI2 SS08 – Class 1 “Introduction” Slide 20
