A Prototype Intraoral Periapical Sensor with High Frame Rates for a 2.5D Periapical Radiography System

Abstract

X-ray radiography is currently used in dentistry and can be divided into two categories: two-dimensional (2D) radiographic images (e.g., using periapical film, cephalometric film, and panoramic X-ray) and three-dimensional (3D) radiographic images (e.g., using dental cone-beam computed tomography (CBCT)). Among them, 2D periapical film images are most commonly used. However, 2D periapical film compresses 3D image information into a 2D image, which means that depth cannot be identified from the image. Such compressed images lose a considerable amount of information, reducing their clinical applicability. A 2.5D periapical radiography system prototype was developed by our research team. Our previous study indicated that this prototype could be used to capture images at different depths of an object. However, the prototype was limited by its commercially available intraoral periapical sensor, which had a low temporal resolution and could not capture multiple images in a short period of time. Therefore, the total time required for image capture was too long for practical clinical application. The present study developed a high-frame-rate intraoral periapical sensor with a sensor imaging speed of up to 15 Hz. The primary components of the developed intraoral periapical sensor include a scintillator, complementary metal oxide semiconductor chip, component circuit board, and video processing board. The external dimensions of the sensor are 41×26×6.6 mm3. The performance of the developed high-frame-rate intraoral periapical sensor was verified through qualified and quantified analyses using line pairs. The results showed that the resolution of the developed intraoral periapical sensor could reach 18 lp/mm. The sensor was further installed in our 2.5D periapical radiography system to conduct image capturing. The results indicated that the developed sensor could be used for high-frame-rate imaging to incorporate tomosynthesis to obtain reconstructed slice images of different depths. The developed sensor has the potential for clinical dentistry applications in the future.

Geometrical Calibration of a 2.5D Periapical Radiography System

“…The long shooting time not only causes discomfort for patients but also generates artefacts in the reconstructed images due to natural breathing motions or unconscious tiny swings of patients during shooting. Therefore, our team also developed a high-frame-rate intraoral periapical sensor [12] which can reach a shooting speed of 15 Hz and reduce the shooting time to within 10 s.…”

“…Although the prototype of this proposed system can obtain reconstructed images in different depths, the shooting time is over 10 min because current commercially available digital X-ray sensors are unable to continuously shoot at high frame rates, rendering them inapplicable to clinical dentistry [9][10][11]. Therefore, our team developed a high-frame-rate sensor in 2019 [12]. This sensor can achieve a frame rate of up to 15 Hz, which substantially reduces the shooting time to under 10 s, thus increasing its clinical feasibility.…”