title: Second-generation dual-energy computed tomography of the abdomen: radiation dose comparison with 64- and 128-row single-energy acquisition.
abstract: OBJECTIVE
  This study was designed to compare the radiation dose in abdominal dual-energy (DE) and single-energy (SE) acquisitions obtained in clinical practice with a second-generation DE computed tomography (DECT) and to analyze the dose variation in comparison with an SE acquisition performed with a 64-row SECT (SECT).
  
  
  METHODS
  A total of 130 patients divided into 2 groups underwent precontrast and portal abdominal 128-row CT examination. In group A, DE portal acquisition was performed using a detector configuration of 2 × 40 × 0.6 mm, tube A at 80 kVp and a reference value of 559 mAs, tube B at 140 kVp and a reference value of 216 mAs, pitch 0.6, and online dose modulation; group B underwent SE portal acquisition using a detector configuration of 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. Group C consisted of 32 subjects from group A previously studied with 64-row SECT using the following parameters: detector configuration 64 × 0.6 mm, 120 kVp and a reference value of 180 mAs, pitch 0.75, and online dose modulation. In each group, the portal phase dose-length product and radiation dose (mSv) were calculated and normalized for a typical abdominal acquisition of 40 cm.
  
  
  RESULTS
  After normalization to standard 40-cm acquisition, a dose-length product of 599.0 ± 133.5 mGy · cm (range, 367.5 ± 1231.2 mGy · cm) in group A, 525.9 ± 139.2 mGy · cm (range, 215.7-882.8 mGy · cm) in group B, and 515.9 ± 111.3 mGy · cm (range, 305.5-687.2 mGy · cm) in group C was calculated for portal phase acquisition.A significant radiation dose increase (P < 0.05) was observed in group A (10.2 ± 2.3 mSv) compared with group B (8.9 ± 2.4) and group C (8.8 ± 1.9 mSv). No significant difference (P > 0.05) was reported between SE 64- and 128-row acquisitions. A significant positive correlation between radiation dose and body mass index was observed in each group (group A, r = 0.59, P < 0.0001; group B, r = 0.35, P < 0.0001; group C, r = 0.20, P = 0.0098).
  
  
  CONCLUSIONS
  In clinical practice, abdominal DECT acquisition shows a significant but minimal radiation dose increase, on the order of 1 mSv, compared with 64- and 128-row SE acquisition. The slightly increased radiation dose can be justified if the additional information obtained using a spectral imaging approach directly impacts on patient management or reduce the overall radiation dose with the generation of virtual unenhanced images, which can replace the precontrast acquisition.
authors.affiliation: Department of Radiological Sciences, Oncology and Pathology, University of Rome Sapienza-Polo Pontino, Latina, Italy. carlodececco@gmail.com
authors.forename: Carlo Nicola
authors.initials: CN
authors.lastname: De Cecco
authors.forename: Anna
authors.initials: A
authors.lastname: Darnell
authors.forename: Napoleón
authors.initials: N
authors.lastname: Macías
authors.forename: Juan Ramón
authors.initials: JR
authors.lastname: Ayuso
authors.forename: Sonia
authors.initials: S
authors.lastname: Rodríguez
authors.forename: Jordi
authors.initials: J
authors.lastname: Rimola
authors.forename: Mario
authors.initials: M
authors.lastname: Pagés
authors.forename: Ángeles
authors.initials: Á
authors.lastname: García-Criado
authors.forename: Marco
authors.initials: M
authors.lastname: Rengo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Muscogiuri
authors.forename: Andrea
authors.initials: A
authors.lastname: Laghi
authors.forename: Carmen
authors.initials: C
authors.lastname: Ayuso
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001822:Body Burden; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011860:Radiography, Abdominal / Q000706:statistics & numerical data*; D015900:Radiography, Dual-Energy Scanned Projection / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D055815:Young Adult