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Optimal beam quality for chest flat panel detector system: realistic phantom study

  • Chie Kuwahara
  • Takatoshi AokiEmail author
  • Nobuhiro Oda
  • Jun Kawabata
  • Koichiro Sugimoto
  • Michiko Kobayashi
  • Masami Fujii
  • Yukunori Korogi
Chest
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Abstract

Objective

To investigate optimal beam quality for chest flat panel detector (FPD) system by semi-quantitatively assessment using a realistic lung phantom.

Materials and methods

Chest FPD radiographs were obtained on a realistic lung phantom with simulated lung opacities using various X-ray tube voltage levels (90–140 kV) with/without copper filter. Entrance skin dose was set to maintain identical for all images (0.1 mGy). Three chest radiologists unaware of the exposure settings independently evaluated the image quality of each simulated opacity and normal structure using a 5-point scale (+ 2: clearly superior to the standard; + 1: slightly superior to the standard; 0: equal to the standard; − 1: slightly inferior to the standard; − 2: clearly inferior to the standard). The traditional FPD image obtained at a tube voltage of 120 kV was used as the standard. The scores of image quality were statistically compared using the Wilcoxon rank test with Bonferroni correction.

Results

FPD images using 90-kV shot with copper filter were superior to the traditional 120-kV shot without filter with respect to the visibility of vertebra, pulmonary vessels, and nodules overlapping diaphragm and heart (p < 0.05). There was no significant difference with respect to the visibility of all other simulated lung opacities (lung nodules except for overlying diaphragm/heart and honeycomb opacity) between each tube voltage level with/without copper filter and the traditional 120-kV shot without filter.

Conclusion

Image quality of FPD images using 90 kV with copper filtration is superior to that using standard tube voltage when dose is identical.

Key Points

• FPD image quality using 90 kV with filter is superior to that using traditional beam.

• Ninety-kilovolt shot with copper filter may be suitable for chest FPD image.

• Clinical study dealing with chest FPD beam optimization would be warranted.

Keywords

Digital radiography Chest radiography Physics Dose Image quality 

Abbreviations

CNRs

Contrast-to-noise ratios

CR

Computed radiography

DR

Digital radiography

ESD

Entrance skin dose

FPD

Flat panel detector

ICC

Intraclass correlation coefficients

PMMA

Polymethyl methacrylate

Notes

Funding

The authors state that this work has not received any funding.

Compliance with ethical standards

Guarantor

The scientific guarantor of this publication is Takatoshi Aoki.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Informed consent was waived because of phantom study.

Ethical approval

Institutional Review Board approval was not required because of phantom study.

Methodology

• experimental

• performed at one institution

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Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Chie Kuwahara
    • 1
  • Takatoshi Aoki
    • 1
    Email author
  • Nobuhiro Oda
    • 2
  • Jun Kawabata
    • 1
  • Koichiro Sugimoto
    • 1
  • Michiko Kobayashi
    • 1
  • Masami Fujii
    • 1
  • Yukunori Korogi
    • 1
  1. 1.Department of RadiologyUniversity of Occupational and Environmental HealthKitakyushuJapan
  2. 2.Department of Radiological TechnologyKyoto College of Medical ScienceKyotoJapan

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