Journal article Open Access

A Study of Dose Distribution and Image Quality under an Automatic Tube Current Modulation (ATCM) System for a Toshiba Aquilion 64 CT Scanner Using a New Design of Phantom

S. Sookpeng; C. J. Martin; D. J. Gentle

Automatic tube current modulation (ATCM) systems are available for all CT manufacturers and are used for the majority of patients. Understanding how the systems work and their influence on patient dose and image quality is important for CT users, in order to gain the most effective use of the systems. In the present study, a new phantom was used for evaluating dose distribution and image quality under the ATCM operation for the Toshiba Aquilion 64 CT scanner using different ATCM options and a fixed mAs technique. A routine chest, abdomen and pelvis (CAP) protocol was selected for study and Gafchromic film was used to measure entrance surface dose (ESD), peripheral dose and central axis dose in the phantom. The results show the dose reductions achievable with various ATCM options, in relation with the target noise. The doses and image noise distribution were more uniform when the ATCM system was implemented compared with the fixed mAs technique. The lower limit set for the tube current will affect the modulations especially for the lower dose option. This limit prevented the tube current being reduced further and therefore the lower dose ATCM setting resembled a fixed mAs technique. Selection of a lower tube current limit is likely to reduce doses for smaller patients in scans of chest and neck regions.

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  • Kalender W A. Computed Tomography Fundamentals, System Technology, Image Quality, Applications. 2nd ed. Erlangen: Publicis Corporate Publishing; 2005.
  • Kalra M K, Maher M M, Toth T L, Schmidt B, Westerman B L, Morgan H T, et al. Techniques and applications of automatic tube current modulation for CT. Radiology 2004; 233(3): 649-57.
  • Kalra M, Maher M, Toth T, Kamath R, Halpern E, Saini S. Comparison of Z-axis automatic tube current modulation technique with fixed tube current CT scanning of abdomen and pelvis. Radiology 2004; 232(2): 347-53.
  • Lee E J, Lee S K, Agid R, Howard P, Bae J M, terBrugge K. Comparison of image quality and radiation dose between fixed tube current and combined automatic tube current modulation in craniocervical CT angiography. American Journal of Neuroradiology 2009; 30(9): 1754-9.
  • Lee S, Yoon SW, Yoo SM, Ji YG, Kim KA, Kim SH, Lee JT. Comparison of image quality and radiation dose between fixed tube current and combined automatic tube current modulation. Acta Radiologica 2011; 52(10):1101-6. [10] Martin C J, Gentle D J, Sookpeng S, Loveland J. Application of Gafchromic film in the study of dosimetry methods in CT phantoms. Journal of Radiological Protection 2011; 31(4): 389-409. [11] Angel E. Sure Exposure: Low dose diagnostic image quality. Toshiba America Medical Systems; 2009. [12] Ferreira T, Rasband W. The ImageJ User Guide - Version 1.44.2011 (cited 2011 10 February); Available from: http://imagej.nih.gov/ij/docs/user-guide.pdf.
  • Papadakis A E, Perisinakis K and Damilakis J. Automatic exposure control in pediatric and adult multidetector CT examinations: a phantom study on dose reduction and image quality. Medical Physics 2008; 35 4567-76.
  • Peng Y, Li J, Ma D, Zhang Q, Liu Y, Zeng J, et al. Use of automatic tube current modulation with a standardized noise index in young children undergoing chest computed tomography scans with 64-slice multidetector computed tomography. Acta Radiologica 2009; 50(10): 1175-81.
  • Rizzo S, Kalra M, Schmidt B, Dalal T, Suess C, Flohr T, et al. Comparison of angular and combined automatic tube current modulation techniques with constant tube current CT of the abdomen and pelvis. American Journal of Roentgenology 2006; 186(3): 673-9.
  • Soderberg M, Gunnarsson M. Automatic exposure control in computed tomography-an evaluation of systems from different manufacturers. Acta Radiologica 2010; 6: 625-34.
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