What is the Research Question?

• Teacher - Cindy Johnson

• School - Palacios High School

• Mentor – Dr. John Ford

• Department of Nuclear Engineering

(Radiation Biologist)

• Partner in Research – Bret Breitenkamp

HOW DO LOW DOSES OF BACKGROUND OR EXOTIC PARTICLE

RADIATION AFFECT THE RISK OF CANCER OR TISSUE INJURY IN

HUMANS

The Answer:

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’sBackground

• 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