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  • NLST CT Images -- General Details

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New Series Descriptions consist of 11 coded comma-separated values, listed below.  Code value descriptions may be found in the attachment Series-Description-Details.xlsx.

  • (1) Screening Year
  • (2) Image Type
  • (3) Manufacturer
  • (4) Scanner Model
  • (5) Convolution Kernel
  • (6) Reconstruction Diameter
  • (7) Slice Thickness
  • (8) kVp
  • (9) mAs*
  • (10) Effective mAs*
  • (11) Pitch*

* In order to calculate 'effective mAs' (=mAs/pitch), one needs to first determine mAs and pitch.  Understanding both of these require extensive reading of manufacturer DICOM conformance statements and explanations from the manufacturers.  Values neede to determine mAs and pitch are sometimes stored in private attributes.  Discussions with manufacturers' engineers allowed us to interpret those private attributes and extract the information necessary to to determine effective mAs, mAs, and pitch. Extractions were made prioir to the removal of DICOM private tags because some contained protected health information (PHI). Where pitch could not be determined, a 'null' is reported.

DICOM Standard -- CT Image Module Attributes

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