title: 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.
abstract: OBJECTIVE
  To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  • 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.
authors: Department of Radiology, University of Erlangen, Maximiliansplatz 1, 91054 Erlangen, Germany. matthias.may@uk-erlangen.de
authors: Matthias S
authors: MS
authors: May
authors: Paul
authors: P
authors: Deak
authors: Axel
authors: A
authors: Kuettner
authors: Michael M
authors: MM
authors: Lell
authors: Wolfgang
authors: W
authors: Wuest
authors: Michael
authors: M
authors: Scharf
authors: Andrea K
authors: AK
authors: Keller
authors: Lothar
authors: L
authors: Häberle
authors: Stephan
authors: S
authors: Achenbach
authors: Martin
authors: M
authors: Seltmann
authors: Michael
authors: M
authors: Uder
authors: Willi A
authors: WA
authors: Kalender
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012189:Retrospective Studies; D012737:Sex Factors; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol