Radiation Dose Metrics and the Effect of CT Scan Protocol Parameters

  • Sue Edyvean
  • Maria Lewis
  • Alan Britten
Part of the Medical Radiology book series (MEDRAD)


The CT scanner consists of many hardware and software features that affect patient dose. Many of these are controlled by the user, or are implicit within organ specific scan protocols. To understand many of these features and their implications on radiation dose to the patient, it is valuable to understand the CT dose indices that are commonly used and their limitations. This chapter begins by reviewing currently used, and accepted, dose descriptors for CT scanners, and outlines some of the limitations of these parameters whilst still advocating their valid use in the description of dose characteristics of CT scanners, and specifically in the comparison of CT scan protocols. The second part of the chapter discusses the effect of the scanner and scan protocol parameters on the dose to the patient. Specifically these are separated into some key hardware features, and then parameters which are usually selectable by the user within a scan protocol. A brief description and overview of these features are given, as well as aspects of their implications on image quality.


Image Noise Beam Width Patient Dose Dose Length Product Automatic Exposure Control 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Department of Physics and Clinical Engineering, St. George’s HospitalImPACT CT Scanner Evaluation CentreLondonUK

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