• Journal of radiological science and technology
• /
• v.44 no.3
• /
• pp.195-203
• /
• 2021

Although intra oral dental x-ray is a lower dose than other radiological examinations, pediatric patients are known to have a higher risk of radiation damage than adults. For this reason, pediatric dental x-ray requires management of dose evaluation and imaging conditions during the examination. In this study, the dose calculation program ALARA-Dental(child/adult) was used to evaluate the organ dose and effective dose exposed to each examination site during intra oral imaging of children during dental radiographic examination, and dose analysis according to the imaging conditions was performed. As a result, the highest organ dose distribution was shown at 0.044 ~ 0.097 mGy in all are as of the mucous membrane of oral cavity except for the maxillary incisors and canines. Also, in the case of the thyroid gland, the maxillary canine and maxillary premolar examination showed 0.027 and 0.020 mGy, respectively, and the dose distribution was 15.4% to 70.0% higher than that of the mandibular examination. As for the effective dose calculated during intra oral imaging, the maxillary anterior and canine examinations showed the highest effective doses of 0.005 and 0.004 mSv, respectively, and the maxillary area examination showed a higher dose distribution on average than the mandible.

• Imaging Science in Dentistry
• /
• v.33 no.1
• /
• pp.21-26
• /
• 2003

Purpose: To investigate the characteristics of the newly marketed, Insight dental X-ray film. Materials and Methods: Kodak Ultraspeed (DF-58), E-speed, Agfa Dentus M2, and Kodak Insight (IP-21) films were radiographed using a Trophy intra-oral radiographic machine. 10 step exposure times were prepared and each step exposure was monitored using a FH 40G (ESM Eberline Instruments) dosimeter for each of the 4 types of intra-oral film. All films were manually processed and the radiographic densities at 6 sites of each processed film were measured, and the characteristic curves of each of the 4 types intra-oral films were created utilizing these dosimetric data and radiographic densities, based on ISO 5779. The film contrast, speed, and base plus fog density of Insight film were compared with those of the 3 other films examined in this experiment. Results : E-speed film showed greatest average gradients followed by Insight film. E-speed and Ultraspeed film showed great average gradients at low density levels. Insight film showed the fastest speed followed by E-speed, Dentus M2 and Ultraspeed film. Dentus M2 film showed greatest base plus fog density level followed by Insight film. Conclusion : Kodak Insight film showed fastest film speed with comparable film contrast on characteristic curve.

• Nuclear Engineering and Technology
• /
• v.33 no.5
• /
• pp.514-525
• /
• 2001

Optimum characteristics of digital X-ray sensor components were analyzed to develop intra- oral dental digital X-ray image sensor using indirect method. Parametric analysis was carried out to optimize the phosphor thickness and the fiber optic plate (FOP) coupling to charge coupled device (CCD). X-ray absorption and light diffusion in the phosphor layer were analyzed by the Monte Carlo method. Real time X-ray image was obtained with prototype X- ray image sensor using general CCD camera with 1∼10 Ip/mm resolution. It has been previously shown that large resolution degradation in X-ray images was caused by miss alignment of FOP to CCD and optical adhesive selection. In this study, we reported that X-ray image quality was greatly improved by using optimized characteristics of alignment device and phosphor thickness.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.5
• /
• pp.262-266
• /
• 2013

A new concept of periapical radiography, intra oral x-ray tube and detector system is introduced. It is new system that a miniature x-ray tube is inserted into mouse and it acquired digital image using external detector. In this study, we have investigated temperature and dose distribution of insertional x-ray tube for periapical radiography. To analyze temperature characteristic of x-ray tube, we attached the thermocouple to surface of x-ray tube and we measured the temperature according to distance. Also, we measured the dose distribution of a miniature x-ray tube according to distance. As a result, temperature was constant to $27^{\circ}C$ over 2mm without cooling system, dose distribution of x-ray tube was 3.14 and 1.84mGy in 3 and 5cm, respectively. Therefore, the proposed x-ray system works in lower dose than conventional dental x-ray system. Thus, it is considered that new concept of system will have a significant effect on medical imaging technology.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.48 no.4
• /
• pp.94-101
• /
• 2011

Various kinds of medical imaging devices have been studied to develop periapical radiography. However, there are some problems such as high x-ray exposure rate and pains for patients because of the problems caused by intra-oral sensor based radiography system. In this study, a new concept of periapical radiography, intra oral X-ray tube and detector system, is introduced to solve these problems. This system is made up of miniature X-ray tube based on subminiature thermal electron or cold electron, CMOS based detector, and a body including automatic position and system control devices. In order to confirm the possibility of proposed new concept to periapical radiography, miniature x-ray tube from XOFT corporation is used to develop new x-ray system, and the performance evaluation of this system is performed according to collimator. Also, dental images are compared after acquiring both images from existing system versus new concept of system. As a result, new concept of system showed excellent image. Thus, it is considered that new concept of system will have a significant effect on medical imaging technology.

• Nuclear Engineering and Technology
• /
• v.48 no.3
• /
• pp.799-804
• /
• 2016

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

• Imaging Science in Dentistry
• /
• v.42 no.2
• /
• pp.115-119
• /
• 2012

Today, ultrasound imaging is being widely used to assess soft tissue lesions in the maxillofacial region. However, ultrasound investigations of intra-osseous lesions are rare, especially for tumors of the jaws. This report emphasized the capability of this useful imaging modality in identification of the characteristics of malignant conditions involving the bone. Mesenchymal chondrosarcoama, one of the unusual malignant conditions of the jaw, was presented in a young male with significant facial swelling. Different imaging modalities parallel with the histopathologic investigation confirmed the diagnosis. Interestingly, destruction of the bony cortex and new bone formation with a characteristic "sun ray appearance", highly suggestive of sarcomas, was manifested on the ultrasonograph. Thus, this report presented the ultrasonographic features of chondrosarcoma of mandible and considered the ultrasonography to be a useful imaging modality to evaluate intra-osseous jaw lesions.

• The Journal of the Korean dental association
• /
• v.14 no.1
• /
• pp.29-31
• /
• 1976

90 Cases of diabetics who came to department of internal medicine and dental clinic, National Medical Center, and 90 Cases of patients who came to dental clinic without general symptom were examined with oral examination and intra-oral x-ray study, from May, 1975 to Oct. , 1975. The obtained results were as follow : In the diabetics, gingval inflammaory changes, alveolar bone resorption and tiih mobility were more severe than nondiabetics who had similar local initants in the oral cavities.

• The Journal of the Korean dental association
• /
• v.20 no.1 s.152
• /
• pp.59-62
• /
• 1982

290 cases of diabetics and 290 cases of non-diabetics who came to the department of Internal Medicine and Dental clinic in the National Medical Center were examined with oral examination and intra-oral x-ray study from February, 1977 to January, 1981. The obtained results were as follows; In the diabetics gingival inflammatory changes, alveolar bone resorption and tooth mobility were more severe than non-diabetics who had similar local irritants in the oral cavities.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.22 no.1
• /
• pp.87-94
• /
• 1992

The purpose of this study was to evaluate the effect of scatter radiation to dental x-ray film with long time-exposure in the different structures of the tooth, by using pinhole camera. For this study, pinhole camera, skull with tooth, and pocket dosimeter were used. The radiation with 70 and 90kVp and exposure time (minimum: 2.5 min., maximum 10 hrs.) was projected to the film in the pinhole camera. And density of the obtained x-ray film was measured with densitometer. In the intra-oral film taking, the amount of exposure of the scatter radiation affecting the thyroid gland area was measured with the dosimeter at the thyroid gland. The density of radiographs was compared in radiation projected with or without the metal cone of dental machine. The effect of the back scatter radiation to the film was also evaluated when the lead foil was removed. The obtained results were as follows: 1. A pinhole camera was a valuable device for locating the source of x-ray. 2. The scatter radiation affected the dental x-ray film when the radiation source was exposed. more than 5 hours'. In that case, the density of the scatter radiation could be observed visually. 3. The scatter radiation caused by short exposure of dental radiation didn't affect the diagnostic quality of the dental x-ray film. 4. The differences of densities between the tooth and the soft tissue according to exposure time showed 0.16 in 5 hours' exposure & 0.17 in 10 hours' exposure at 70 kVp & 0.12 in 5 hours' exposure & 0.13 in 10 hours' exposure at the 90kVp. 5. The differences of densities between the tooth and the soft tissue according to kVp showed no difference between 5 hours' exposure of tooth at 70 kVp and soft tissue at 90 kVp, but showed 0.05 high density in tooth when 10 hours' exposure at 90 kVp. 6. No difference of density was on radiographs taken with or without dental machine cone. 7. Back scatter radiation was recorded image of radiographs for only 3 min. 8. The amounts of the scatter radiation exposed to the thyroid gland in intraoral film taking were 1.12 mr in upper anterior, 0.55 mr in upper posterior, 2.75 mr in lower anterior, and 1.92 mr in lower posterior teeth.