Development of Portable Digital Radiography System with a Device for Monitoring X-ray Source-Detector Angle and Its Application in Chest Imaging.

This study developed a device measuring the X-ray source-detector angle (SDA) and evaluated the imaging performance for diagnosing chest images. The SDA device consisted of Arduino, an accelerometer and gyro sensor, and a Bluetooth module. The SDA values were compared with the values of a digital angle meter. The performance of the portable digital radiography (PDR) was evaluated using the signal-to-noise (SNR), contrast-to-noise ratio (CNR), spatial resolution, distortion and entrance surface dose (ESD). According to different angle degrees, five anatomical landmarks were assessed using a five-point scale. The mean SNR and CNR were 182.47 and 141.43. The spatial resolution and ESD were 3.17 lp/mm (157 µm) and 0.266 mGy. The angle values of the SDA device were not significantly difference as compared to those of the digital angle meter. In chest imaging, the SNR and CNR values were not significantly different according to the different angle degrees. The visibility scores of the border of the heart, the fifth rib and the scapula showed significant differences according to different angles (p < 0.05), whereas the scores of the clavicle and first rib were not significant. It is noticeable that the increase in the SDA degree was consistent with the increases of the distortion and visibility score. The proposed PDR with a SDA device would be useful for application in the clinical radiography setting according to the standard radiography guidelines.

Reduced radiation dose and improved image quality using a mini mobile digital imaging system in a neonatal intensive care unit.

This study was aimed to assess the radiation dose and image quality of a mini-mobile digital imaging (mini-DI) system for neonatal chest radiography and compared to conventional digital radiography (DR). A total of 64 neonates were examined and anatomical landmarks were assessed. The entrance surface dose of mini DI and conventional DR was 26.64±0.15 µGy and 49.11±1.46 µGy, respectively (p<0.001). The mean SNR values for mini-DI and DR were 233.2±5.1 and 31.6±1.2, and 10% MTF values were 131 and 161µm. A newly developed mini-DI is capable of preserving the diagnostic information with dose reduction in neonates under intensive care.

Performance of mobile digital X-ray fluoroscopy using a novel flat panel detector for intraoperative use.

BACKGROUND: Technologies employing digital X-ray devices are developed for mobile settings. OBJECTIVE: To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms. METHODS: An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients. RESULTS: The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 µ m) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 µ Gy and 0.1 µ Gy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 µ Gy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee). CONCLUSIONS: The proposed MDF is suitable for imaging in operating rooms.

Dedicated mobile volumetric cone-beam computed tomography for human brain imaging: A phantom study.

BACKGROUND: Mobile computed tomography (CT) with a cone-beam source is increasingly used in the clinical field. Mobile cone-beam CT (CBCT) has great merits; however, its clinical utility for brain imaging has been limited due to problems including scan time and image quality. OBJECTIVE: The aim of this study was to develop a dedicated mobile volumetric CBCT for obtaining brain images, and to optimize the imaging protocol using a brain phantom. METHODS: The mobile volumetric CBCT system was evaluated with regards to scan time and image quality, measured as signal-to-noise-ratio (SNR), contrast-to-noise-ratio (CNR), spatial resolution (10% MTF), and effective dose. Brain images were obtained using a CT phantom. RESULTS: The CT scan took 5.14 s at 360 projection views. SNR and CNR were 5.67 and 14.5 at 120 kV/10 mA. SNR and CNR values showed slight improvement as the x-ray voltage and current increased (p < 0.001). Effective dose and 10% MTF were 0.92 mSv and 360 µ m at 120 kV/10 mA. Various intracranial structures were clearly visible in the brain phantom images. CONCLUSIONS: Using this CBCT under optimal imaging acquisition conditions, it is possible to obtain human brain images with low radiation dose, reproducible image quality, and fast scan time.