Download Physics of Imaging Systems (ROE, CT, MRI)

RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 1
Master‘s Program in Medical Physics
Physics of
Imaging Systems (ROE, CT, MRI)
Prof. Dr. Lothar Schad
Chair in Computer Assisted Clinical Medicine
Faculty of Medicine Mannheim
University of Heidelberg
Theodor-Kutzer-Ufer 1-3
D-68167 Mannheim, Germany
[email protected]
www.ma.uni-heidelberg.de/inst/cbtm/ckm/
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 2
www.ma.uni-heidelberg.de/inst/cbtm/ckm/
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 3
Introduction
Introduction
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 4
Nobel Prize 2003
Nobel Prize is awarded for MRI technology
landmark achievement transformed healthcare in 20th century
Paul Lauterbur
(1929 - 2007)
Sir Peter Mansfield
(1933 - )
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 5
Diagnostic Imaging: Milestones
1901
W. C. Röntgen (Germany, 1845 - 1923)
discovery of X-rays
1952
Felix Bloch (USA, 1905 - 1983)
Edward M. Purcell (USA, 1912 - 1997)
development of a new precision method of nuclear magnetism (NMR)
1979
Allan M. Cormack (USA, 1924 - 1998)
Godfrey N. Hounsfield (UK, 1919 - )
development of Computer-Tomography (CT)
1991
Richard R. Ernst (CH, 1933 - )
development of high resolution magnetic resonance spectroscopy (MRS)
2003
Paul C. Lauterbur (USA, 1929 - 2007)
Peter Mansfield (UK, 1933 - )
development of magnetic resonance imaging (MRI)
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 6
Diagnostic Imaging: Pioneers
ROE
PET
“The Making of a Science”
CT
MRI
source: ECR Newsletter 1/2003
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 7
Motivation
Why do we need imaging systems ?
„Addiction“ to image information ?
source: Siemens “100 Jahre Röntgen” 1995
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 8
Information Flow of Sense Organs
- information recording of all sense organs from our surroundings:
self-aware data processing: 100 bit/s
short-term storage:
10 bit/s
long-term storage:
1 bit/s
≈ 109 bit/s
→ selection and filtering 1:10 million !
information flow
see
hear
108 bit/s
5×104 bit/s
smell
102 bit/s
taste
10 bit/s
CNS
flowing capacity to shortterm storage: 16 bit/s
is recognized by the human
awareness
source: Drischel. „Einführung in die Biokybernetik“, Akademie-Verlag 1972
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 9
Conclusion
Imaging Systems are
supporting the most effective
and powerful sensor !
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 10
Physicians´ Ranking of Innovations 2001
Fuchs and Sox. Health Affairs - Sept/Oct 2001
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 11
Diagnostic Imaging: Principal
object
(human, animal, plant, ...)
radiation source(s)
detector(s)
external
X-rays (Röntgen)
ultrasound (US)
radiofrequency (NMR)
external
film (Röntgen)
piezo-crystal (US)
RF-coil (NMR)
internal
radioactive tracers
(PET, SPECT)
internal
RF-coil
source: http://bio.physik.uni-würzburg.de/public/medphys
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 12
Goal
To look into the object without cutting or
destroying (non-invasively) !
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 13
Diagnostic Imaging: Definition
definition:
• interaction of energy with biological tissue in order to get spatially
resolved information about the physical properties of the underlying
biological structure
• energy has to penetrate through the body for interaction (absorption,
scattering, …)
interpretation of imaging information:
• importance of measured physical properties with respect to
differentiate between normal and diseased tissue (pathology)
• not fully understood
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 14
Diagnostic Imaging: Electromagnetic Wave
PET and MRI are at the end of the spectrum
OCT
NIRF
Visible
Infrared
nuclear medicine / PET
100keV
10keV
Ultraviolet
X-ray
10
19
TV satellite
dish
Hz 10 18 Hz 10 17Hz
16
10 Hz
15
10 Hz
14
10 Hz
Millimeter
THz Gap
gap
13
10 Hz
12
10 Hz
11
10 Hz
Micro-
wave
and RF
10
10 Hz
Frequency
X-ray / CT
imaging
terahertz pulse
imaging (TPI)
ionizing
non-ionizing
magnetic
resonance
imaging
MRI
different energies means different interaction with tissue
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 15
Electromagnetic Wave Penetration
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 16
Diagnostic
Imaging: Overview
Bildgebende
Verfahren
without ionizing
radiation
Nuclear Magnetic
Resonance
spectroscopy
(MRS)
tomography
(MRI)
with ionizing
radiation
Ultrasound
X-rays
planar
tomography
(CT)
Nuclear Medical
Techniques
planar
emission
tomography
(PET)
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 17
Diagnostic Imaging: Anatomy
image by courtesy of Helmut Newton
source: ECR Newsletter 4/2002
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 18
Diagnostic Imaging: Pathology
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 19
Diagnostic Imaging: Animals
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 20
Diagnostic Imaging: System Combination
- anatomic / metabolic imaging
PET / MRI
Set-up of the McPET system inside the 1.5 T clinical scanner.
McPET’s ring of detectors is placed inside the MRI coil (white
arrow) and transmits its output to the MC-PMTs, enclosed in the
RF-shielded box in the foreground, via doubleclad optical fibers
(black arrow).
PET / CT
The brain shows a large, left posterior / temporal / parietal
metastasis. In the transaxial views, a hyper-metabolic area,
measuring 2.2 x 2.1 cm with a solid center, is seen,
surrounded by edema (arrow on fused image details
hypermetabolic area).
A pair of PET (a) and MR (b) images contemporaneously
obtained from the C-phantom at 1.5 T.
source: GE Medical Systems
Farahani et al. JMR 1999
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 21
Biomedical Imaging
source: ECR Newsletter 4/2002
RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 22
Diagnostic Imaging: Field of Application
main focus of diagnostic imaging
• diagnostic
• therapy-planning and -monitoring
• screening
• monitoring of interventions
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RUPRECHT-KARLSUNIVERSITY HEIDELBERG
Computer Assisted Clinical Medicine
Prof. Dr. Lothar Schad
12/9/2008 | Page 23
Diagnostic Imaging: Properties
X-Ray
CT
MR
US
+++
–/+
++
–
–
+++
–
++
–
++
+
++
++
++
++
–
+
+
++
+
*
+
+
++
psychological stress
physical stress
invasiv
small
high
no
medium
high
no
high
small
no
small
small
no
costs (EUR)
ca. 40
ca. 100
ca. 400
ca. 10
imaging of
bone
soft tissue
vessel
function
volume
real-time
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