DNA dosimeter measurements of beam profile using a novel simultaneous processing technique

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Molecular Biology

Background:

• A DNA dosimeter (DNAd) was previously developed for measuring radiation dose using DNA double-strand breaks (DSBs).
• Existing methods have been validated under transient-charged particle equilibrium (TCPE) conditions.
• Quantification of DSBs relies on the probability of double strand break (PDSB_o).

Purpose of the Study:

• To develop a novel technique for processing and analyzing DNAd samples.
• To establish a new metric, PDSB_n, for quantifying DNA-DSBs under non-TCPE conditions.
• To improve the efficiency and accuracy of DNAd-based radiation dosimetry.

Main Methods:

• Simultaneous processing of multiple DNAd samples using a 384-well plate.
• Application of a new probability of double strand break (PDSB_n) formulation.
• Testing in a non-TCPE scenario using beam penumbra measurements at the edge of a 10 × 10 cm field.
• Comparison of PDSB_n measurements with film dosimetry.

Main Results:

• The new PDSB_n metric demonstrated improved agreement with film measurements in the beam penumbra compared to PDSB_o.
• Distances to agreement for PDSB_n were as low as 0.06 cm, significantly better than PDSB_o (0.26 cm).
• The developed separation technique reduced sample analysis time from 200 minutes to 30 minutes for 25 samples.

Conclusions:

• The novel DNAd processing and analysis technique, incorporating PDSB_n, enhances radiation dose quantification accuracy, particularly in non-TCPE conditions.
• The improved efficiency of the new method makes DNAd a more practical tool for radiation dosimetry.
• This advancement offers a more precise method for assessing radiation exposure in complex scenarios.