Purpose
Dynamic Chest Radiography (DCR) system has been clinically introduced since November 2018. DCR system consists of a conventional radiography system (RadSpeed Pro; Shimadzu, Kyoto, Japan), a flat-panel detector (FPD) (AeroDr fine; Konica Minolta, Tokyo, Japan), and a dedicated imaging workstation for DCR (DI-X1, Konica Minolta). This DCR system, which can achieve a short examination time for optimal productivity, can provide time-resolved radiographs (the maximum acquisition duration: 20 seconds [sec]) with a high frame rate (15 frames/sec) and a wide field of view (17 inches x...
Methods and materials
We used our original rotation phantom (a 20-cm-diameter acrylic disc) and a commercially available lung phantom (Lungman phantom; Kyoto Kagaku, Kyoto, Japan) (Figure 5) with simulated nodules and diaphragm (Figure 6) to perform the following three experiments with standard acquisition parameters used in clinical settings and all the pulse widths available with the DCR system: 1) quantitative evaluation of blurring and ghost artifact, 2) qualitative evaluation of nodule visibility, and 3) quantitative evaluation of diaphragmatic movement. The system specifications and acquisition parameters used in this...
Results
Quantitative evaluation of blurring and ghost artifact
Blurring percentages based on the FWHM at both 20 and 30 rpm were less than 1% at all the pulse widths and comparable among the different pulse widths (Table 2). Blurring percentages based on the area was 10.0% at 30 rpm and pulse width of 8 msec (Figure 15) but less than 5% with other combinations of the rotation speed and pulse width (Table 3). Ghost artifact percentages at the first to tenth frame at both 20 and...
Conclusion
Blurring, ghost artifact, and visibility of pulmonary nodules and measurement of diaphragmatic movement are almost independent of the pulse widths on DCR with standard acquisition parameters used in clinical settings. We thus recommend use of the pulse width of 4 msec to preserve adequate image noise level in clinical settings, because a significant blurring may be problematic for very swiftly moving objects at the pulse width of 8 msec.
Personal information and conflict of interest
N. Hashimoto:
Nothing to disclose
H. Machida:
Nothing to disclose
K. Yamashita:
Nothing to disclose
T. NAKAI:
Nothing to disclose
J. Yamaguchi:
Nothing to disclose
J. Shudo:
Nothing to disclose
A. Nakanishi:
Nothing to disclose
H. Takeuchi:
Nothing to disclose
K. Yokoyama:
Nothing to disclose
References
1. Hata A, Yamada Y, Tanaka R, Nishino M, Hida T, Hino T. Dynamic Chest X-Ray Using a Flat-Panel Detector System: Technique and Applications. Korean J Radiol. 2020;21:e189.
2. Yamada Y, Ueyama M, Abe T, Araki T, Abe T, Nishino M, et al. Difference in diaphragmatic motion during tidal breathing in a standing position between COPD patients and normal subjects: time-resolved quantitative evaluation using dynamic chest radiography with flat panel detector system (“dynamic X-ray phrenicography”). Eur J Radiol. 2017;87:76–82.
3. Hida T, Yamada Y, Ueyama...