[New Method of Paired Comparison for Improved Observer Shortage Using Deep Learning Models].

Purpose: The aim of this study was to validate the potential of substituting an observer in a paired comparison with a deep-learning observer.

Methods: Phantom images were obtained using computed tomography. Imaging conditions included a standard setting of 120 kVp and 200 mA, with tube current variations ranging from 160 mA, 120 mA, 80 mA, 40 mA, and 20 mA, resulting in six different imaging conditions.

[Study of X-ray Beam Quality and Contrast-to-Noise Ratio of Lung Nodules in Chest FPD Radiography: Monte Carlo Simulation Using Chest Model Phantom].

Objectives: Contrast-to-noise ratio (CNR) of four X-ray beams (90 kV with 0.15-mm Cu filter, 90 kV with 0.2-mm Cu filter, 120 kV without filter and 120 kV with 0.

[Image quality and detection performance of a direct digital radiography system].

The physical characteristics of a direct amorphous Selenium (a-Se) digital fluoroscopy and radiography system were investigated. Pre-sampled modulation transfer functions (MTF) were measured using a slit method. Noise power spectra were determined for different input exposures by fast Fourier transform of uniformly exposed samples.

Physical imaging properties and low-contrast performance of a newly developed flat-panel digital radiographic system.

We investigated the clinical usefulness of a newly developed flat-panel detector (FPD) system by comparing its physical imaging properties and low-contrast detectability with those of a current FPD system. The newly developed CsI-based indirect FPD (Canon, CXDI-40C) and current Gd(2)O(2)S-based FPD (Canon CXDI-11) systems were used. Characteristic curves, resolution properties, radiographic noise, detective quantum efficiencies (DQEs) and low-contrast detectability for both systems were measured.

[CR-mammography with pixel size of 50 microm and dual-sided reading system: effect of the oblique incident of the X-ray beam on imaging properties and detection].

In mammography units, the X-ray tube focal spot is located directly above the chest wall edge of the detector. Therefore, the X-ray beam is incident at a different angle along the cathode-anode axis. When the X-ray beam is incident on the imaging plate (IP) at a relatively large angle, the resolution property of a new imaging plate with dual-sided reading system would be degraded compared with the conventional imaging plate because of the parallax effect, which produces a shift in the image on two sides of the imaging plate.

New CR system with pixel size of 50 microm for digital mammography: physical imaging properties and detection of subtle microcalcifications.

Purpose: To investigate the physical imaging properties and detection of simulated microcalcifications of a new computed radiography (CR) system with a pixel size of 50 microm for digital mammography.

Materials And Methods: New and conventional CR were employed in this study. The new CR system included a high-resolution imaging plate coupled with the FCR5000MA (50 microm pixel pitch) including transparent support and a dual-sided reader.

[Full-field digital mammography with amorphous silicon-based flat- panel detector: physical imaging characteristics and signal detection].

The physical characteristics of a clinical amorphous silicon-based flat-panel imager for full-field digital mammography were investigated. Pre-sampled modulation transfer functions (MTF) were measured by using a slit method. Noise power spectra were determined for different input exposures by fast Fourier transform.

[ROC analysis of detection of interval changes in interstitial lung diseases on digital chest radiographs using the temporal subtraction technique].

Purpose: To demonstrate the clinical usefulness of a temporal subtraction technique for the detection of interval changes in various interstitial lung diseases on digital chest radiographs.

Materials And Methods: One hundred pairs of chest radiographs in 34 patients (63 with and 37 without interval changes) with various interstitial lung diseases were selected. All cases were confirmed by serial chest computed tomography (CT) and ascertained by radiologists.

[Usefulness of the opposite direction for Stenvers' method].

In otorthinolaryngology, Stenvers' method is employed in radiography of the pyramid (internal acoustic meatus and semicircular canals). However, in cases of dizziness, where the prone position is difficult to achieve, we occasionally use the opposite Stenvers' method instead of the conventional one. This makes it possible to perform radiography with the patient in the supine position.

[Canon's flat-panel detector].

We measured and evaluated digital, pre-sampling and overall imaging properties (characteristic curve, modulation transfer function (MTF), Wiener spectrum (WS), noise equivalent quanta (NEQ) ) for Cannon's flat-panel detector (FPD), Fuji computed radiography (FCR) and screen-film (S/F) systems, respectively. First, the digital and overall characteristic curves of FPD and FCR systems were more wide dynamic range than that of the S/F system. Second, the pre-sampling and overall MTF of FPD system were better than those of FCR system a little at lower spatial frequencies than 0.