Transcript Radiation-Johnson-1

What is the Research Question?
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Teacher - Cindy Johnson
School - Palacios High School
Mentor – Dr. John Ford
Department of Nuclear Engineering
(Radiation Biologist)
• Partner in Research – Bret
Breitenkamp
The Answer:
HOW DO LOW DOSES OF
BACKGROUND OR EXOTIC PARTICLE
RADIATION AFFECT THE RISK OF
CANCER OR TISSUE INJURY IN
HUMANS
INTRODUCTION AND BACKGROUND
• Type of Engineering in lab - Nuclear
• Field of Application - Biology, Physics, Medicine
• Background Information on Research
 Uses thyroid, trachea, and other cells from
rats
 Exposes them to low levels of radiation
 Such as x-rays, alpha sources or beams,
proton beams, ion beams, and gamma
sources
 Uses different exposure methods such as
single cell suspensions, monolayer cultures,
or whole excised trachea
Background continued
 CR-39 (plastic polymer) is placed along
side, front or back of the tissue
 Expose tissue to radiation
 Cut, examine, and evaluate the tissue
 Transplant cells back into rat and evaluate
at different time periods
 Develop, examine, photograph, score, and
measure the CR-39 slide for radiation hits
The ASSAY
 Assay - the data measured in the research
 Number of tumors in transplant
 Colonies that survived in culture
 Changes in proteins or cells that could
lead to cancer (preneoplastic
transformation)
 Number of Gap junction
communications
Research Results
• Some of transplanted tissue formed
tumors after irradiation
• Preneoplastic transformation is cell density
dependent
• Neutrons can cause tumors in transplants
• Alpha particles are not effective at
inducing preneoplastic transformations
• Bystander effects were observed between
cells irradiated and those that were not
Comparison of Normal and
Transplant Follicles
Transplant Tumor
Relevance of the Research
• Little is known about the effects of low
level radiation on humans
• Exposure to low levels of radiation occurs
daily in medicine and space
• Observed effects in rat cells could be
beneficial to cancer research and
medicine in humans
• Use to determine the amount of low dose
radiation human tissue could be exposed
to without damage.
Relevance continued
• Determine if the guidelines for low dose
radiation need to be lowered for human
safety
• Establish the importance of control
guidelines for disposal of low dose
radiation and equipment containing low
dose radioactive material
• Develop materials to protect astronauts
from space radiation
Dr. John Ford’s
Background
• BS and MS in Nuclear Engineering from
Mississippi State University
• Ph.D in Biomedical Sciences from University of
Tennessee at Knoxville
• 1987-1993 Research at Oak Ridge National Lab
• 1994-1998 Research at MRC-Radiation and
Genome Stability Unit in the United Kingdom
• 1998-present Texas A and M
Overview of My Research Activities
• Activity 1-Develop and analyze irradiated
CR-39 slides
• Activity 2- Determine more information
about the radiation environment of the
polymer that contained irradiated tissue
• Activity 3- My class project or projects:
– Determine which polymer would make the
best low level radiation detector
– Determine which polymer would be best at
stopping alpha particles
Research Protocol
• Source of radiation is counted using a
Gieger-Mueller tube
• CR-39 polymer is cut into microscopic
slide size with a scalpel and labeled.
• CR-39 is exposed to the source by placing
the source face down onto the slide.
(different sources could be used)
• After the determined time period, the
source is removed by inverting the slide.
Developing CR-39
• After exposure the slides are placed in
6.5N NaOH and incubated for 4 hours at
65-70 degrees Celsius.
• The NaOH is changed at 2 hrs.
• The slides are then washed for several
minutes under running water
• Slides are air dried and 3-10 fields of view
at 450x are photographed for scoring and
1-2 at 750x are obtained for measurement.
Heavy ion streak in plastic
Alpha particle penetrations
Data Information
• Data Generated:
– Count holes in several fields of view in a
microscope
– Estimated the number of holes on the slide in
mm squared
– Do this for each type of polymer used
• Data Interpreted:
– Compare and graph the data collected from
the different types of polymers
– Determine which polymer is the best at
detecting radiation and blocking alpha
particles
– Determine which polymer would be the most
cost effective to use
Importance of Research
• Best polymer to use in radiation detectors
• Best low cost polymer that blocks radiation
• Use to determine radiation found in homes
or space
• Increase understanding of low dose
radiation and its effects for my students
Summary
• Dr. Ford is working on how low dose
radiation affects cells.
• This can be used to determine how much
low dose radiation is acceptable for the
human cell
• The data could also be used to determine
controls for low dose radioactive waste
and disposal of that waste
• I can adapt this research to use in my
Chemistry class by evaluating the effects
of radiation on different polymers
Chemistry Class Lesson
• Introduce Nuclear Chemistry as part of the
unit on Atoms
• Students experiment to determine the
sensitivity of polymers to alpha radiation
• Students experiment to determine which
polymer would shield alpha particles the
best
• Students use a Gieger counter to
determine environmental materials that
contain radiation and determine the
amount of radiation given off
• Students determine their annual exposure
to background and low dose radiation
Acknowledgements
• Dr. John Ford for research, pictures and
help
• Texas A&M University for opportunity
• National Science Foundation for financial
support and opportunity
• South Texas Nuclear Power Plant