Affiliations: Center for Bioengineering and School of Electrical and
Computer Engineering, University of Oklahoma, Norman, OK, USA | Department of Radiology, University of Alabama at
Birmingham, Birmingham, AL, USA
Note: [] Corresponding author: Hong Liu, Center for Bioengineering and
School of Electrical and Computer Engineering, University of Oklahoma, 110 West
Boyd Street, Devon Energy Hall 150, Norman, OK 73019, USA. Tel.: +1 405 325
4286; Fax: +1 405 325 7066; E-mail: liu@ou.edu
Abstract: The goal of this preliminary study was to investigate the effects of
x-ray beam hardening on the detective quantum efficiency (DQE) and the
radiation dose of an inline x-ray imaging system. The ability to decrease the
risk of harmful radiation to the patient without compromising the detection
capability would more effectively balance the tradeoff between image quality
and radiation dose, and therefore benefit the fields of diagnostic x-ray
imaging, especially mammography. The DQE and the average glandular dose were
both calculated under the same experimental conditions for a range of beam
hardening levels, corresponding to no added beam hardening and two thicknesses
each of Rhodium (Rh) and Molybdenum (Mo) filters. The dose calculation results
demonstrate a reduction of 15% to 24% for the range of beam hardening
levels. The comparison of all quantities comprising the DQE exhibit very close
correlation between the results obtained without added beam hardening to the
results corresponding to the range of beam hardening levels. For the specific
experimental conditions utilized in this preliminary study, the results are an
indication that the use of beam hardening holds the potential to reduce the
radiation dose without decreasing the performance of the system. Future studies
will seek to apply this method in a clinical environment and perform a
comprehensive image quality evaluation, in an effort to further evaluate the
potential of beam hardening to balance the tradeoff between dose and image quality.
Keywords: Diagnostic x-ray imaging, beam hardening, radiation dose, detective quantum efficiency (DQE), noise equivalent quanta (NEQ), modulation transfer function (MTF), noise power spectrum (NPS)
