Effect of CT scan protocols on x-ray-induced DNA double-strand breaks in blood lymphocytes of patients undergoing coronary CT angiography

• Published in: European radiology Vol. 20; no. 12; pp. 2917 - 2924
• Main Authors: Kuefner, M. A., Grudzenski, S., Hamann, J., Achenbach, S., Lell, Michael, Anders, K., Schwab, S. A., Häberle, L., Löbrich, M., Uder, M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.12.2010; Springer Nature B.V
• Subjects: Biological Assay - methods; Coronary Angiography - methods; Diagnostic Radiology; DNA - radiation effects; DNA Damage; Experimental; Female; Humans; Imaging; Internal Medicine; Interventional Radiology; Lymphocytes - physiology; Lymphocytes - radiation effects; Male; Medicine; Medicine & Public Health; Neuroradiology; Radiation Dosage; Radiology; Tomography, X-Ray Computed - methods; Ultrasound; γ-H2AX; Coronary CT angiography; Biological dose; DNA double-strand breaks; Dual-source CT
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-010-1873-9

Aims To compare in vivo DNA lesions induced during helical and sequential coronary computed tomography angiography (CTA) and to evaluate the effect of CT parameters on double-strand break (DSB) levels. Methods Thirty-six patients were examined with various CT protocols and modes (helical scan, n  = 27; sequential scan, n  = 9) either using a 64-slice dual-source or a 128-slice CT system. Blood samples were obtained before and 30 min after CT. Lymphocytes were isolated, stained against the phosphorylated histone variant γ-H2AX, and DSBs were visualised by using fluorescence microscopy. Results DSB yields 30 min after CTA ranged from 0.04 to 0.71 per cell and showed a significant correlation to DLP ( ρ  = 0.81, p  < 0.00001). Median DSB yield and median DLP were significantly lower after sequential compared to helical CT examinations (0.11 vs. 0.37 DSBs/cell and 249 vs. 958 mGy cm, p  < 0.00001). Additional calcium scoring led to an increase in DLP ( p  = 0.15) and DSB levels ( p  = 0.04). DSB levels normalised to the DLP showed a significant correlation to the attenuation of the blood ( ρ  = 0.53, p  = 0.01) and a negative correlation to the body mass index of the patients ( ρ  = −0.37, p  = 0.06). Conclusion γ-H2AX immunofluorescence microscopy allows one to determine dose-related effects on x-ray-induced DSB levels and to consider individual factors which cannot be monitored by physical dose measurements.