Radiation dose considerations by intra-individual Monte Carlo simulations in dual source spiral coronary computed tomography angiography with electrocardiogram-triggered tube current modulation and adaptive pitch
- 275 Downloads
To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine.
Coronary CTA was performed for 56 patients with electrocardiogram-triggered tube current modulation (TCM) and heart-rate (HR) dependent pitch adaptation. Individual Monte Carlo (MC) simulations were performed for dose assessment. Retrospective simulations with constant tube current (CTC) served as reference. Lung tissue was segmented and used for organ and effective dose (ED) calculation.
Estimates for mean relative ED was 7.1 ± 2.1 mSv/100 mAs for TCM and 12.5 ± 5.3 mSv/100 mAs for CTC (P < 0.001). Relative dose reduction at low HR (≤60 bpm) was highest (49 ± 5%) compared to intermediate (60–70 bpm, 33 ± 12%) and high HR (>70 bpm, 29 ± 12%). However lowest ED is achieved at high HR (5.2 ± 1.5 mSv/100 mAs), compared with intermediate (6.7 ± 1.6 mSv/100 mAs) and low (8.3 ± 2.1 mSv/100 mAs) HR when automated pitch adaptation is applied.
Radiation dose savings up to 52% are achievable by TCM at low and regular HR. However lowest ED is attained at high HR by pitch adaptation despite inferior radiation dose reduction by TCM.
• Monte Carlo simulations allow for individual radiation dose calculations.
• ECG-triggered tube current modulation (TCM) can effectively reduce radiation dose.
• Slow and regular heart rates allow for highest dose reductions by TCM.
• Adaptive pitch accounts for lowest radiation dose at high heart rates.
• Women receive higher effective dose than men undergoing spiral coronary CT-angiography.
KeywordsDual source computed tomography ECG-pulsing Adaptive pitch Coronary angiography Monte Carlo radiation dose simulation
We are grateful to Werner Bautz, Katharina Anders and Gerd Muschiol for their support in the clinical investigation and Marcel von Straten for his technical support in running the Monte Carlo simulations and providing the dose estimations. This study was supported by the German Government, Bundesministerium für Bildung und Forschung (01EX1012B, “Spitzencluster Medical Valley”).
- 3.Muenzel D, Noel PB, Dorn F, Dobritz M, Rummeny EJ, Huber A (2011) Step and shoot coronary CT angiography using 256-slice CT: effect of heart rate and heart rate variability on image quality. Eur Radiol. doi: 10.1007/s00330-011-2185-4
- 4.Moscariello A, Takx RA, Schoepf UJ et al (2011) Coronary CT angiography: image quality, diagnostic accuracy, and potential for radiation dose reduction using a novel iterative image reconstruction technique-comparison with traditional filtered back projection. Eur Radiol 21:2130–2138PubMedCrossRefGoogle Scholar
- 20.Protection ICoR (1990) ICRP Publication 60: 1990 Recommendations of the ICRP. Annals of the ICRP Volume 21/1–3. International Commission on Radiological ProtectionGoogle Scholar
- 24.Ketelsen D, Fenchel M, Buchgeister M et al (2011) Estimation of radiation exposure of different dose saving techniques in 128-slice computed tomography coronary angiography. Eur J Radiol. doi: 10.1016/j.ejrad.2011.01.052
- 33.Bischoff B, Hein F, Meyer T et al (2010) Comparison of sequential and helical scanning for radiation dose and image quality: results of the Prospective Multicenter Study on Radiation Dose Estimates of Cardiac CT Angiography (PROTECTION) I Study. AJR Am J Roentgenol 194:1495–1499PubMedCrossRefGoogle Scholar
- 41.Dewey M, Vavere AL, Arbab-Zadeh A et al (2010) Patient characteristics as predictors of image quality and diagnostic accuracy of MDCT compared with conventional coronary angiography for detecting coronary artery stenoses: CORE-64 Multicenter International Trial. AJR Am J Roentgenol 194:93–102PubMedCrossRefGoogle Scholar
- 42.Protection ICoR (2007) P103: the 2007 Recommendations of the International Commission on Radiological Protection. Annals of the ICRP. ICRP, pp 37(32–34): p 31–332Google Scholar