Impact of Low-Dose CT Radiation on Gene Expression and DNA Integrity

Area of Science:

• Medical Imaging
• Radiation Biology
• Molecular Diagnostics

Background:

• Computed tomography (CT) is a primary source of medical imaging radiation exposure.
• Assessing risks from low-dose radiation is challenging, often relying on the linear no-threshold model.
• Understanding cellular responses to low-dose radiation is crucial for accurate risk assessment.

Purpose of the Study:

• To investigate radiation-induced transcriptomic and DNA damage alterations in peripheral blood cells following CT scans.
• To compare gene expression changes between in vivo and ex vivo blood sample incubation.
• To evaluate the potential of transcriptional biomarkers as biodosimetry tools for low-dose radiation exposure.

Main Methods:

• Collected peripheral whole blood from 60 patients before and after CT scans.
• Quantified gene expression of radiation-responsive genes using qRT-PCR.
• Assessed DNA double-strand breaks (DSB) via γ-H2AX + 53BP1 focus staining in a subset of patients.

Main Results:

• Differential gene expression varied significantly between in vivo and ex vivo incubation, with ex vivo masking true low-dose effects.
• In vivo samples showed significant upregulation of genes including EDA2R, MIR34AHG, PHLDA3, DDB2, FDXR, and AEN.
• A linear dose-dependent upregulation was observed for several genes, with AEN and FDXR showing high explained variance.
• DSB analysis indicated a slight, non-significant increase in damage post-exposure.

Conclusions:

• Transcriptional biomarkers are sensitive indicators of low-dose radiation exposure from medical imaging.
• In vivo gene expression analysis is more reflective of actual radiation effects than ex vivo.
• These biomarkers show promise as clinically applicable biodosimetry tools, highlighting the need for dose optimization in CT scans.