ECSE-6963 Biological Image Analysis. Lecture #7: Common Medical Imaging Instrument: MRI & PET Scanner Badri Roysam Rensselaer Polytechnic Institute, Troy, New York 12180. Center for Sub-Surface Imaging & Sensing. Recap. Probes, media, and objects Basic types of microscopes
Common Medical Imaging Instrument:
MRI & PET Scanner
Rensselaer Polytechnic Institute, Troy, New York 12180.
Center for Sub-Surface Imaging & Sensing
1952 Nobel Prize: Felix Bloch and Edward Purcell
1991 Nobel Prize: Richard R. Ernst
Nuclei with highest biological abundance
T1 = spin-lattice relaxation time
T2 = spin-spin relaxation time
Fourier Transform the FID signal to obtain a frequency spectrum for each angle
Backproject the frequency spectra to reconstruct image!
Cheap & Fast
Good resolution with bone
Hard to distinguish soft tissues without contrast agent
Can’t distinguish atoms beyond their X-Ray cross-section
X-Rays harmful to body
Expensive & Slow
Can distinguish bone and various soft tissues
Can distinguish specific atoms
No known health hazards to MR imagingCT vs. MRI
Showing a tumor
3-camera SPECT instrument
Gamma Photon #1
Gamma Photon #2
1. Create a simple 2-D phantom like the one shown in Lecture 6, and use the “radon” and “iradon” functions in MATLAB to simulate a CT scanner with 1, 2, 4, 48, and 96 angles. In other words, generate an example like the one shown in class. http://www.mathworks.com/access/helpdesk/help/toolbox/images/transfo9.shtml.
Note: You should be able to do the above exercise simply by following the instructions in the tutorials on the mathworks website. They do not need specialized mathematics knowledge.
2. Search the Internet for a sample MRI image of the human brain. Plot a histogram of T1, T2 and Proton density values from this image.
3. Search the Internet for a sample PET image, and an MRI image for the same patient. Generate an overlay of the PET image over the MRI image using MATLAB or an image viewer such as PaintShop Pro or Adobe Photoshop.
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