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Optimizing the Response and Cost of a DNA Double-Strand Break Dosimeter

M Obeidat

M Obeidat, K Cline , S Stathakis , N Papanikolaou , K Rasmussen , A Gutierrez , CS Ha , SE Lee , EY Shim* , N Kirby* , University of Texas HSC SA, San Antonio, TX, *Co-Principal Investigators


TH-CD-201-11 (Thursday, August 4, 2016) 10:00 AM - 12:00 PM Room: 201

Purpose:A DNA double-strand break (DSB) dosimeter was developed to measure the biological effect of radiation. The goal here is to refine the fabrication method of this dosimeter to reproducibly create a low coefficient of variation (CoV) and reduce the cost for the dosimeter.

Methods:Our dosimeter consists of 4 kilo-base pair DNA strands (labeled on one end with biotin and on the other with fluorescein) attached to streptavidin magnetic beads. The final step of the DNA dosimeter fabrication is to suspend these attached beads in phosphate-buffered saline (PBS). The amount of PBS used to suspend the attached beads and the relative volume of the DNA strands to the beads both affect the CoV and dosimeter cost. We diluted the beads attached with DNA in different volumes of PBS (100, 200, and 400 μL) to create different concentrations of the DNA dosimeter. Then we irradiated these dosimeters (50 μL samples) in a water-equivalent plastic phantom at 25 and 50 Gy (three samples per dose) and calculated the CoV for each dosimeter concentration. Also, we used different masses of DNA strands (1, 2, 8, 16, 24, and 32 μg) to attach to the same volume of magnetic beads (100 μL) to explore how this affects the cost of the dosimeter.

Results:The lowest CoV was produced for the highest concentration of dosimeter (100 μL of PBS), which created CoV of 2.0 and 1.0% for 25 and 50 Gy, respectively. We found that the lowest production cost for the dosimeter occurs by attaching 16 μg of DNA strands with 100 μL of beads.

Conclusion:: We optimized the fabrication of the DNA dosimeter to produce low CoV and cost, but we still need to explore ways to further improve the dosimeter for use at lower doses.

Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by Yarmouk University (Irbid, Jordan) and CPRIT (RP140105)

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