title: Tracking Patterns of Nonadherence to Prescribed CT Protocol Parameters.
abstract: OBJECTIVE
  Quantification of the frequency, understanding the motivation, and documentation of the changes made by CT technologists at scan time are important components of monitoring a quality CT workflow.
  
  
  METHODS
  CT scan acquisition data were collected from one CT scanner for a period of 1 year. The data included all relevant acquisition parameters needed to define the technical side of a CT protocol. An algorithm was created to sort these data in groups of irradiation events with the same combinations of scan acquisition parameters. For scans modified at scan time, it was hypothesized that these examinations would show up only once in the organized data. A classification scheme was developed to place each "one-off" examination into a category related to what motivated the scan-time change.
  
  
  RESULTS
  A total of 132,707 irradiation events were organized into 434 groups of unique scan acquisition parameters. One hundred forty-four irradiation events had acquisition parameters that showed up only once in the data. These "one-offs" were classified as follows: 25% represented rarely used protocols, 17% were due to service scans, 16% were changed for unknown and therefore undesired reasons, 15% were changed by technologists trying to adapt protocol to patient size, 12% were allowable scan-time changes, 8% of scans had tube current maxed out, and 6% of scans were changed to a higher dose mode as requested by radiologists.
  
  
  CONCLUSIONS
  The outcome of this study suggests many areas of needed technologist training and chances for optimizing this institution's CT protocols.
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin; Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin. Electronic address: tszczykutowicz@uwhealth.org.
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Szczykutowicz
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Annelise
authors.initials: A
authors.lastname: Malkus
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin; Amanda Ciano is now an employee of GE Healthcare, Chicago, Illinois.
authors.forename: Amanda
authors.initials: A
authors.lastname: Ciano
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Myron
authors.initials: M
authors.lastname: Pozniak
mesh_terms: D019983:Guideline Adherence / Q000706:statistics & numerical data*; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000592:standards* / Q000706:statistics & numerical data; D011785:Quality Assurance, Health Care / Q000379:methods* / Q000592:standards; D000069079:Radiation Exposure / Q000517:prevention & control* / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000592:standards* / Q000706:statistics & numerical data*; D014922:Wisconsin
keywords: CT; Protocol review; compliance; protocol optimization