Radiation dosimetry for electron beam CT

Cynthia H McCollough, Frank E. Zink, Richard L. Morin

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

PURPOSE: To measure the radiation dose profile, multiple-scan average dose (MSAD), and computed tomography dose index (CTDI) for electron beam CT and to determine the accuracy of ionization-chamber and manufacturer estimates of patient dose. MATERIALS AND METHODS: High-resolution dose profiles along the longitudinal axis were acquired at several positions within the scan plane with use of radiographic film. The full-width-at-half-maximum values, peak radiation dose, CTDI, and MSAD were calculated from the digitized film profiles. CTDI was also measured with an ionization chamber. RESULTS: The full-width-half-maximum value of the radiation profiles were significantly wider than the nominal scan width for the 6-mm single-section and 8-mm multisection modes. In the single-section mode, the CTDI underestimated the MSAD by 15%-30%. The multisection radiation profile was nonuniform and asymmetric. CONCLUSION: Patient doses in electron beam CT are approximately 125% of the ionization-chamber CTDI measurements in the single-section mode. For the multisection mode, the average patient dose over the scan volume is approximately 70%-85% of the ionization-chamber CTDI measurements.

Original languageEnglish (US)
Pages (from-to)637-643
Number of pages7
JournalRadiology
Volume192
Issue number3
StatePublished - Sep 1994

Keywords

  • Computed tomography (CT), electron beam
  • Computed tomography (CT), radiation exposure
  • Coronary vessels, calcification

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology

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