1. Introduction to Modern Medical Imaging
Allen T. Newton, Ph.D.
Institute of Imaging Science, Department of Radiology
Vanderbilt University
PAVE 2014

2. Medical Imaging
The goal is to better visualize structure or function in the living or non-living organism, animal or human
Involves collaborations with mathematicians, physicists, engineers, chemists and biologists
Work with physicians to meet their diagnostic and treatment evaluation needs
Look at a couple of key components of medical imaging
Look at some examples from MRI, ultrasound, CT

3. Imaging Science Physics Chemistry Biology Medicine Computer Science
Math
Engineering

4. Physicist/engineer (PhD) 4 yrs of college 5-7 yrs of graduate school
Radiologists (MD)
4 yrs of college
4 yrs of medical school
Physicist/engineer (PhD)
4 yrs of college
5-7 yrs of graduate school
improve
interpret
Medical Imaging
Then, to end the lecture, the final message is the definition of imaging science. We can guide them into helping us define imaging science since through the lecture we have showed them that its is a multidisciplinary science, and we can name all or most of the different fields of science that have a role in imaging, I believe that we have a slide for that, and that imaging can be use for research and for medical purposes.
create
Technologists (RT)
2-4 yrs of college
2 yrs of technical school

5. How do we make medical images?
X-ray images are made using x-rays, which are waves like radiowaves or ultraviolet light but with higher frequency and smaller wavelength.

6. Magnetic Resonance Imaging (MRI)
The Major Imaging Modalities
Magnetic Resonance Imaging (MRI)
X-ray Imaging
Computed Tomography (CT)
Positron Emission Tomography (PET)
Ultrasound (US)

7. X-ray Imaging The Major Imaging Modalities
Magnetic Resonance Imaging (MRI)
X-ray Imaging
Computed Tomography (CT)
Positron Emission Tomography (PET)
Ultrasound (US)

8. Computed Tomography (CT)
The Major Imaging Modalities
Magnetic Resonance Imaging (MRI)
X-ray Imaging
Computed Tomography (CT)
Positron Emission Tomography (PET)
Ultrasound (US)

9. Positron Emission Tomography (PET)
The Major Imaging Modalities
Magnetic Resonance Imaging (MRI)
X-ray Imaging
Computed Tomography (CT)
Positron Emission Tomography (PET)
Ultrasound (US)

10. So, you are playing soccer…
… you collide with another player, and collapse in pain on the ground
You have pretty intense pain in your lower left leg
How bad is it and how do we find out?

11. So, you go to the Emergency Room…
… and the attending physician orders an X-ray of your injured leg
What are they looking for?
What will the X-ray show?
 The X-ray shows a bad break in your tibia
General Message:
What is the problem?
Can imaging solve the problem?
How?
Image adapted from

12. Spatial Resolution 32x32, 7.5 mm2 64x64, 3.75 mm2 128x128, 1.87 mm2

13. Spatial resolution
7T MRI, 0.6x0.6x1.0 mm3 resolution

14. Contrast

15. A Magnetic Resonance Imaging Scanner

16. Magnetic Resonance imaging
Can generate 2D and 3D views in any plane
Uses no ionizing radiation
Extremely versatile modality
Spatial resolution: humans~100, animals~25 microns
Coronal
Sagittal
Axial

17. Magnetic Resonance imaging

18. Magnetic Resonance imaging
MRI showing blood vessels in brain

20. Assessing brain white matter tracks
Magnetic Resonance imaging
Assessing brain white matter tracks
Bright in coherent white matter
Darker where
1) Fibers diverge/cross, or
2) No preferred orientation
Orientation is color code by direction
 Red = Right/Left
 Green = Anterior/Posterior
 Blue = Superior/Inferior
Reveals structure within white matter
Adam Anderson, Ph.D. 20

21. Finding white matter tracks
Magnetic Resonance imaging
Finding white matter tracks
 Establishes connections between different brain regions
Adam Anderson, Ph.D. 21

22. Some examples from cancer imaging

23. Signal Intensity time courses
MRI in cancer imaging
Signal Intensity time courses
3D rendering of tumor
anatomical MRI

24. X-rays in cancer imaging, 1/2
Mammogram displaying calcification, increased density
Mrs. Röntgen's hand, the first X-ray picture of the human body ever taken

25. X-rays in cancer imaging, 2/2
Standard radiography yields a 2-D projection of a 3D object, whereas CT allows for true 3-D image acquisition
CT acquires a series of projections from many angles around the subject; each set of projections is then reconstructed via a “backprojection” algorithm
Developed by Sir Godfrey Houndsfield, won 1972 Nobel Prize in Medicine/Physiology
Spatial resolution: humans~200 microns, animals~35 micron
Munden, et al, Radiology, 2005; 237:803-18

26. PET in cancer imaging, 1/2
Some radioactive isotopes (18F, 15O, etc) emit positrons:
Such elements can be incorporated into metabolically relevant compounds
Emitted positron encounters electron, they annihilate leaving 2 photons traveling in opposite directions which are measured by ring of detectors
Images generated using very similar computations as in CT
Spatial resolution: humans and animals ~2 mm
Most common PET tracer is FDG (flourodeoxyglucose), a glucose analog
18FDG
(blood)
(tissue)
18FDG-6-PO4
(cells) X

27. PET in cancer imaging, 2/2 CT PET CT/PET Dominique Delbeke
Dominique Delbeke
CT PET CT/PET

28. This week Today: Overview Tuesday: X-Ray & Computed Tomography (CT)
Wednesday: Ultrasound, SPECT, PET
Thursday: MRI
Friday: fMRI lab !!!!!!