Transcript 8 Radiography

Radiography
What are some ways we can see
inside of something?
X-Ray Imaging
 Electromagnetic radiation
between Ultraviolet and Gamma
rays
 Produced by accelerated
electrons colliding with tungsten
anode and projected at body part
 Calcium in bones and added
contrasts of barium or iodine
absorb x-rays
 Image receptor digital films
reads black where x-rays
penetrated through body
MRI
 Machine creates a magnetic
field that aligns the
magnetization of some atoms
in the body and radio
frequency fields further alter
the alignment. Nuclei produce
rotation magnetic field, which
is detected by the scanner
Primarily used to examine soft tissue in
body, brain, muscles, heart and cancers
No ionizing radiation
Ultrasound
 Cyclic sound pressure with frequency greater
than 20,000 hertz
 Transducer sends and receives
sound signals in medium
 Used by bats for hunting
 Medical sonography used
for soft tissue diagnosis,
fetuses, interventional
procedures
CT Scan
 X-ray Computed
Tomography (CT)
 Tomography-means
imaging by sections from
penetrating wave
 X-ray source rotates
helically about patient or
specimen to create 3D
image from sectioning
 Useful for preventative
medicine
PET Scan
 Positron Emission
Tomography
 Positron - antielectron
(positive electron)
 System uses a tracer (positronemitting radionuclide) to
detect gamma rays emitted by
the collision of these positrons
with electrons
 Fludeoxyglucose (sugar) is
commonly used as tracer
Attenuate
 Means to reduce or weaken
 The higher the attenuation coefficient the
greater the ability of the material to reduce
or weaken the radiation beam
 This can be done by scattering, absorption
 What attenuates x-rays during medical
procedures?
(0.025 eV)
Compare Different Materials
 Cadmium ( Cd )
 Lead ( Pb )
 Plastic ( (CH3)n )
Which will block the radiation?
Material
X-rays
Neutrons
Cadmium ( Cd )
Yes
Yes
Lead ( Pb )
Yes
No
Polyethylene ( (CH3)n )
No
Yes
Neutron Imaging System
Video output
Gamma rays
(photons)
neutrons
electrons
Reactor
D2O Tank
Phosphorescent screen (similar to
the one in your TV) converts
electrons to visible light.
Scintillation material
(GdO2S)converts neutrons
into gamma rays through
neutron capture reactions
Neutron Imaging System “3.5 hours slide”
courtesy of Danielle Hauck.5/17/2004- rev. 9/29/04 CCD
Photocathode
coverts photons to electrons
through photoelectric effect
CODE Box
Student Project to Demonstrate X-Ray/Neutron Radiography
Was originally in cardboard shoe box, but was replaced by more durable aluminum.
Cadmium
Lead
C OD E
X-Ray Image
Cadmium
Lead
Plastic
C OD E
P S U
Neutron Radiograph
Lion’s Paw
neutron video
Hydrogen Fuel Cell Imaging
Fuel Cell research
conducted at RSEC
Hydrogen Fuel Cell Imaging
Water Calibration Wedge
Hydrogen Fuel Cell Imaging
Figure it out
 Look at the next slide and see if you can
figure out what will show up on x-rays
Cad
Lead
Plastic
X-Ray
Figure it out neutrons
 Look at the picture again and figure out
what you will see with neutrons.
Neutron Radiograph
Cad
Lead
Plastic
X-Ray
Neutron Radiograph
Cadmium
Lead
Plastic
X-Ray
Neutron Radiograph
Cad
Lead
Plastic
X-Ray
Neutron Radiograph
WSHI design project
 Design a project using
cadmium, lead and
plastic that will look
different with x-rays
and neutrons
 Table shows what
material blocks the
radiation
Material
Cadmium
Lead
Plastic
X-rays
Yes
Yes
No
Neutrons
Yes
No
Yes
Resources
 Images courtesy of WikiMedia Commons and Breazeale Nuclear
Reactor
 Hubbell, J. H. "NIST: X-Ray Mass Attenuation Coefficients." National
Institute of Standards and Technology. Web. 17 Sept. 2011.
<http://www.nist.gov/pml/data/xraycoef/index.cfm>.
 Whaites, Eric; Roderick Cawson (2002). Essentials of Dental
Radiography and Radiology. Elsevier Health Sciences. pp.ﾊ15ﾐ20.
ISBNﾊ044307027X.
 Special Thanks to: Joanna Kinney and Jeremiah Lynch for preparing
this presentation at Penn State University, Radiation Science &
Engineering Center