Automatic Exposure Control in Multidetector-row CT

Part of the Medical Radiology book series (MEDRAD)


Automatic exposure control (AEC) is one of the most important aspects of radiation dose and image quality optimization for CT scanning. It is important to use this technique appropriately in order to obtain CT examinations with required image quality and/or radiation dose levels as improper use can lead to much lower or much higher radiation doses to patients undergoing CT examinations. There is similarity in basic principle behind different AEC techniques across different CT vendors but there are considerable differences between how the techniques are applied on platforms of different CT vendors. This chapter discusses various techniques of AEC available for use on clinical CT equipments.


Tube Current Modulation Adaptive Statistical Iterative Reconstruction Automatic Exposure Control Noise Index Automatic Tube Current Modulation 
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  1. Althen JN (2005) Automatic tube-current modulation in CT—a comparison between different solutions. Radiat Prot Dosim 114:308–312CrossRefGoogle Scholar
  2. Brink M, de Lange F, Oostveen LJ, Dekker HM, Kool DR, Deunk J, Edwards MJ, van Kuijk C, Kamman RL, Blickman JG (2008) Arm raising at exposure-controlled multidetector trauma CT of thoracoabdominal region: higher image quality, lower radiation dose. Radiology 249:661–670PubMedCrossRefGoogle Scholar
  3. Brisse HJ, Robilliard M, Savignoni A, Pierrat N, Gaboriaud G, De Rycke Y et al (2009) Assessment of organ absorbed doses and estimation of effective doses from pediatric anthropomorphic phantom measurements for multi-detector row CT with and without automatic exposure control. Health Phys 97:303–314PubMedCrossRefGoogle Scholar
  4. Campbell J, Kalra MK, Rizzo SMR, Maher MM, Shepard J (2005) Scanning beyond anatomic limits of thorax in chest CT: findings, radiation dose and automatic tube current modulation. Am J Roentgenol 185:1525–1530CrossRefGoogle Scholar
  5. Chapman VM, Kalra MK, Grottkau BE, Albright M, Jaramillo D (2005) 16-Slice multidetector CT of the post-traumatic pediatric elbow: optimum parameters and associated radiation dose. Am J Roentgenol 185:516–521Google Scholar
  6. Cody D, McCollough CM (2011) American association of physicists in medicine (AAPM) working group on standardization of CT nomenclature and protocols. AAPM CT Lexicon version 1.1 8/31/2011. Accessed 3 Nov 2011
  7. Dalal T, Kalra MK, Rizzo SM, Schmidt B, Suess C, Flohr T et al (2005) Metallic prosthesis: technique to avoid increase in CT radiation dose with automatic tube current modulation in a phantom and patients. Radiology 236:671–675PubMedCrossRefGoogle Scholar
  8. Giacomuzzi SM, Erckert B, Schopf T, Freund MC, Springer P, Dessl A et al (1996) The smart-scan procedure of spiral computed tomography: a new method for dose reduction. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 165:10–16PubMedCrossRefGoogle Scholar
  9. Greess H, Wolf H, Baum U, Kalender WA, Bautz W (1999) Dosage reduction in computed tomography by anatomy-oriented attenuation-based tube-current modulation: the first clinical results. Rofo 170:246–250PubMedGoogle Scholar
  10. Greess H, Baum U, Wolf H, Lell M, Nomayr A, Schmidt B et al (2001) Dose reduction in spiral-CT: detection of pulmonary coin lesions with and without anatomically adjusted modulation of tube current. Rofo 173:466–470PubMedCrossRefGoogle Scholar
  11. Greess H, Nomayr A, Wolf H, Baum U, Lell M, Bowing B et al (2002) Dose reduction in CT examination of children by an attenuation-based on-line modulation of tube current (CARE Dose). Eur Radiol 12:1571–1576PubMedCrossRefGoogle Scholar
  12. Greess H, Lutze J, Nomayr A, Wolf H, Hothorn T, Kalender WA et al (2004) Dose reduction in subsecond multislice spiral CT examination of children by online tube current modulation. Eur Radiol 14:995–999PubMedCrossRefGoogle Scholar
  13. Jakobs TF, Becker CR, Ohnesorge B, Flohr T, Suess C, Schoepf UJ et al (2002) Multislice helical CT of the heart with retrospective ECG gating: reduction of radiation exposure by ECG-controlled tube current modulation. Eur Radiol 12:1081–1086PubMedCrossRefGoogle Scholar
  14. Kalra MK, Prasad S, Saini S, Blake MA, Varghese J, Halpern EF et al (2002) Clinical comparison of standard-dose and 50% reduced-dose abdominal CT: effect on image quality. Am J Roentgenol 179:1101–1106Google Scholar
  15. Kalra MK, Maher MM, Prasad SR, Hayat MS, Blake MA, Varghese J et al (2003a) Correlation of patient weight and cross-sectional dimensions with subjective image quality at standard dose abdominal CT. Korean J Radiol 4:234–238CrossRefGoogle Scholar
  16. Kalra MK, Maher MM, Saini S (2003b) What is the optimum position of arms for acquiring scout images for whole-body CT with automatic tube current modulation? Am J Roentgenol 181:596–597Google Scholar
  17. Kalra MK, Maher MM, Toth TL, Hamberg LM, Blake MA, Shepard JA et al (2004a) Strategies for CT radiation dose optimization. Radiology 230:619–628CrossRefGoogle Scholar
  18. Kalra MK, Maher MM, Toth TL, Schmidt B, Westerman BL, Morgan HT et al (2004b) Techniques and applications of automatic tube current modulation for CT. Radiology 233:649–657CrossRefGoogle Scholar
  19. Kalra MK, Maher MM, Kamath RS, Horiuchi T, Toth TL, Halpern EF et al (2004c) Sixteen-detector row CT of abdomen and pelvis: study for optimization of Z-axis modulation technique performed in 153 patients. Radiology 233:241–249CrossRefGoogle Scholar
  20. Kalra MK, Maher MM, Toth TL, Kamath RS, Halpern EF, Saini S (2004d) Comparison of Z-axis automatic tube current modulation technique with fixed tube current CT scanning of abdomen and pelvis. Radiology 232:347–353CrossRefGoogle Scholar
  21. Kalra MK, Maher MM, Toth TL, Kamath RS, Halpern EF, Saini S (2004e) Radiation from “extra” images acquired with abdominal and/or pelvic CT: effect of automatic tube current modulation. Radiology 232:409–414CrossRefGoogle Scholar
  22. Kalra MK, Rizzo SM, Novelline RA (2005a) Reducing radiation dose in emergency computed tomography with automatic exposure control techniques. Emerg Radiol 11:267–274CrossRefGoogle Scholar
  23. Kalra MK, Naz N, Rizzo SM, Blake MA (2005b) Computed tomography radiation dose optimization: scanning protocols and clinical applications of automatic exposure control. Curr Probl Diagn Radiol 34:171–181CrossRefGoogle Scholar
  24. Kopka L, Funke M, Breiter N, Hermann KP, Vosshenrich R, Grabbe E (1995) An anatomically adapted variation of the tube current in CT: studies on radiation dosage reduction and image quality. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 163:383–387PubMedCrossRefGoogle Scholar
  25. Lehmann KJ, Wild J, Georgi M (1997) Clinical use of software-controlled X-ray tube modulation with “Smart-Scan” in spiral CT. Aktuelle Radiol 7:156–158PubMedGoogle Scholar
  26. Lim HK, Lee KH, Kim SY, Kim KJ, Kim B, Lee H et al (2011) Does the amount of tagged stool and fluid significantly affect the radiation exposure in low-dose CT colonography performed with an automatic exposure control? Eur Radiol 21:345–352PubMedCrossRefGoogle Scholar
  27. Mastora I, Remy-Jardin M, Delannoy V, Duhamel A, Scherf C, Suess C et al (2004) Multi-detector row spiral CT angiography of the thoracic outlet: dose reduction with anatomically adapted online tube current modulation and preset dose savings. Radiology 230:116–124PubMedCrossRefGoogle Scholar
  28. Miyazaki O, Kitamura M, Masaki H, Nosaka S, Miyasaka M, Kashima K (2005) Current practice of pediatric MDCT in Japan: survey results of demographics and age-based dose reduction. Nippon Igaku Hoshasen Gakkai Zasshi 65:216–223PubMedGoogle Scholar
  29. Mulkens TH, Bellinck P, Baeyaert M, Ghysen D, Van Dijck X, Mussen E et al (2005) Use of an automatic exposure control mechanism for dose optimization in multi-detector row CT examinations: clinical evaluation. Radiology 237:213–223PubMedCrossRefGoogle Scholar
  30. Namasivayam S, Kalra MK, Pottala K, Waldrop S, Hudgins PA (2006) Optimization of z-axis automatic exposure control for multidetector row CT evaluation of neck and comparison with fixed tube current technique for image quality and radiation dose. Am J Neuroradiol 27:2221–2225Google Scholar
  31. Papadakis AE, Perisinakis K, Oikonomou I, Damilakis J (2011) Automatic exposure control in pediatric and adult computed tomography examinations: can we estimate organ and effective dose from mean MAS reduction? Invest Radiol 46:654–662PubMedCrossRefGoogle Scholar
  32. Paul J, Schell B, Kerl JM, Maentele W, Vogl TJ, Bauer RW (2011) Effect of contrast material on image noise and radiation dose in adult chest computed tomography using automatic exposure control: a comparative study between 16-, 64- and 128-slice CT. Eur J Radiol 79:e128–e132PubMedCrossRefGoogle Scholar
  33. Poll LW, Cohnen M, Brachten S, Ewen K, Modder U (2002) Dose reduction in multi-slice CT of the heart by use of ECG-controlled tube current modulation (“ECG pulsing”): phantom measurements. Rofo 174:1500–1505PubMedCrossRefGoogle Scholar
  34. Prakash P, Kalra MK, Kambadakone AK, Pien H, Hsieh J, Blake MA et al (2010a) Reducing abdominal CT radiation dose with adaptive statistical iterative reconstruction technique. Invest Radiol 45:202–210CrossRefGoogle Scholar
  35. Prakash P, Kalra MK, Digumarthy SR, Hsieh J, Pien H, Singh S et al (2010b) Radiation dose reduction with chest computed tomography using adaptive statistical iterative reconstruction technique: initial experience. J Comput Assist Tomogr 34:40–45CrossRefGoogle Scholar
  36. Rizzo SM, Kalra MK, Maher MM, Blake MA, Toth TL, Saini S (2005) Do metallic endoprostheses increase radiation dose associated with automatic tube-current modulation in abdominal-pelvic MDCT? A phantom and patient study. Am J Roentgenol 184:491–496Google Scholar
  37. Rizzo S, Kalra MK, Schmidt B, Suess C, Flohr TG, Blake MA et al (2006) Comparison of angular and combined automatic tube current modulation techniques with constant tube current CT scanning of the abdomen and pelvis. Am J Roentgenol 186:673–679Google Scholar
  38. Singh S, Kalra MK, Moore MA, Shailam R, Liu B, Toth TL et al (2009) Dose reduction and compliance with pediatric CT protocols adapted to patient size, clinical indication, and number of prior studies. Radiology 252:200–208PubMedCrossRefGoogle Scholar
  39. Söderberg M, Gunnarsson M (2010) Automatic exposure control in computed tomography—an evaluation of systems from different manufacturers. Acta Radiol 51:625–634PubMedCrossRefGoogle Scholar
  40. Tack D, De Maertelaer V, Gevenois PA (2003) Dose reduction in multidetector CT using attenuation-based online tube current modulation. Am J Roentgenol 181:331–334Google Scholar
  41. Terada M (2005) Optimization of image quality by CT scanner automatic exposure control systems. Nippon Hoshasen Gijutsu Gakkai Zasshi 61:1384–1386Google Scholar
  42. Wang ZJ, Chen KS, Gould R, Coakley FV, Fu Y, Yeh BM (2011) Positive enteric contrast material for abdominal and pelvic CT with automatic exposure control: what is the effect on patient radiation exposure? Eur J Radiol 79:e58–62PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Department of Radiology, Harvard Medical SchoolMassachusetts General HospitalBostonUSA

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