title: Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography.
abstract: BACKGROUND
  Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern.
  
  
  OBJECTIVE
  To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA.
  
  
  METHODS
  Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test.
  
  
  RESULTS
  Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR ≤65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed.
  
  
  CONCLUSIONS
  Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure.
authors.affiliation: CT and MRI Department, Hygeia Hospital, Athens, Greece. fotisdimi@yahoo.gr
authors.forename: Fotios
authors.initials: F
authors.lastname: Laspas
authors.forename: Dimitra
authors.initials: D
authors.lastname: Tsantioti
authors.forename: Arkadios
authors.initials: A
authors.lastname: Roussakis
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Kritikos
authors.forename: Roxani
authors.initials: R
authors.lastname: Efthimiadou
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kehagias
authors.forename: John
authors.initials: J
authors.lastname: Andreou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide