Transcript Medical Imaging

Medical Imaging
Jessica Ramella-Roman Ph.D.
Instructor
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Office ---> Pangborn Hall -105B
Email ---> [email protected]
Office phone ----> 202 319 6247
Office hours ---> By appointment
Research ---> Biomedical Optics
Lab ---> Pangborn Hall, 118
Textbook & suggested reading
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The essential physics of medical
imaging, second edition, J.T.
Bushberg, J.A. Seibert, E.M.Leidholdt, JR.
J.M. Boone, Editor: Lippincott
Williams&Wilkins
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ISBN 0-683-30118-7
Grading
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40% Homework
30% Midterm Exam
30% Final Exam
http://policies.cua.edu/academicgrad/gradesfull.cfm#iii
CUA Grading System
http://policies.cua.edu/academicgrad/gradesfull.cfm#iii
Class Structure
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1 h 15 min - lecture
20 min break
1 h 15min – lecture
Class in snapshot
Class website
faculty.cua.edu/ramella
Click here
Password is: medical581
ONE WORD!
Class website
faculty.cua.edu/ramella
Notes
Schedule
Homework
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Every one or two weeks
Graded on effort – i.e. 100% if produced
in time
I will return only the answers to the
questions
Midterm / Final
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Close notes, close book
1.5 hr
1 or 2 questions from homework
general questions, example
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How does Xray work?
Medical imaging
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Includes many imaging modalities
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X-ray, Ultrasound, CT, PET, MRI, and
many others
Uses physics, math, engineering tools,
biology, (...) to image different part of the
interior of the human body.
Radiation is:
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Energy that travels through space and
matter
We are interested in electromagnetic
radiation
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Xray
Visible Waves
Gamma rays (…)
Electromagnetic spectrum
wavelength (nm)
1015
1012
109
106
103
100
10-3
10-6
frequency (Hz)
60
1012
16
1018
UV
Radio, TV, Radar, MRI
IR
g-Rays
X-Rays
Radiant Heat
10-12
energy (eV)
10-9
10-6
10-3
1024
100
visible
103
106
Cosmic Rays
109
X-Ray imaging
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Discovered by Wilhelm Roentgen Nov 8, 1895
Published December 12, 1895
Uses X-Rays (0.01-0.1 nm)
Ionizing radiation
10-100 KeV
Resolution: mm
Penetration: all body
Mammography is done with
low power X-rays
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* images from: http://imagers.gsfc.nasa.gov/ems/xrays.html
Magnetic resonance Imaging
(MRI)
Paul Lauterbur and Peter Mansfield 1970-1980
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Uses very powerful magnets (1.5 Tesla) and the nuclear magnetic
resonance properties of the proton
Detects the radio frequency emitted by the protons
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(Proton spin flip)
Tomographic imaging modality
10 minutes for a complete scan
* images from: http://nobelprize.org/medicine/laureates/2003/press.html
Computer Tomography (CT)
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Full body CT inventor 1970-2 Robert Lendley
Uses X-Rays, rotates the source & detector around the body
Very quick (10 sec)
Image soft tissue and vascular network
* images from: http://www.radiologyinfo.org
Ultrasound
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Inventor: Donald 1957, used on pregnant woman in 1958
Uses sound waves
Sound enters the tissues and is reflected by internal structures
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Echoes
It’s a scanning process
Much less harmful than ionizing mechanism
Doppler ultrasound is used to measure flow
* images from: http:///www.medical.philips.com
Nuclear Imaging
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Inventor: Many over the years John & Ernest Lawrence, Ager ...
Uses the decay (X-Ray or Gamma-Ray) of a isotope that was injected in a
patient to image internal organs (emission images)
Gives information on the physiology of the patient
PET-> Positron Emission Tomography
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Radioactive isotopes Fluorine18 and Oxygen 15 emits positrons (e+)
e+ combined to e- produces annihilation radiation
Annihilation radiation similar to gamma-ray but produces 2 photons ( in opposite
directions)
Uses a ring of detector to record the photon
Produces a tomographic image
SPECT-> Single Photon Emission Computed Tomography
Gamma ray or Xray emission from the patient is recorder at several
different angle. (tomography)
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Radioactive isotopes Fluorine18 and Oxygen 15 emits positrons (e+)
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* images from: http:///www.medical.philips.com
Next class is
September 6