• Title/Summary/Keyword: 구내 방사선

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DIAGNOSTIC ABILITY OF THE PERIAPICAL RADIOGRAPHS AND DIGITAL IMAGE IN THE DETECTION OF THE ARTIFICIAL PROXIMAL CARIES (인공적 인접면 치아우식증의 구내방사선사진과 디지털 영상의 진단능 평가)

  • Heo Min-Suk;You Dong-Soo
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.24 no.2
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    • pp.439-450
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    • 1994
  • Recently, the digital image was introduced into radiological image. The digital image has the power of contrast enhancement, histogram control, and other digitally enhancement. At the point of the resolution, periapical radiograph is superior to the digital image, but enhanced digital procedure improves the diagnostic ability of the digital image. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries in conventional radiographs, digital radiographs and enhanced digital radiographs (histogram specification). ROC (Receiver Operating Characteristic) analysis and paired t-test were used for the evaluation of detectability, and following results were acquired: 1. The mean ROC area of conventional radiographs was 0.9274. 2. The mean ROC area of unenhanced digital image was 0.9168. 3. The mean ROC area of enhanced digital image was 0.9339. 4. The diagnostic ability of three imaging methods was not significant difference(p>0.05). So, the digital images had similar diagnostic ability of artificial proximal caries to conventional radiographs. If properly enhanced digital image, it may be superior to conventional radiographs.

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The radiographic depth of approximal root cavities : A comparative study of conventional and digital radiographs (인접면 치근 인공우식병소의 깊이 평가: 구내 일반 방사선사진과 디지털 방사선사진과의 비교)

  • Park Hyun-Jung;Cho Bong-Hae
    • Imaging Science in Dentistry
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    • v.33 no.1
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    • pp.15-20
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    • 2003
  • Purpose : To investigate the reproducibility of the conventional and digital radiographs to determine the depth of approximal root cavities. Materials and Methods : A total of 80 artificial root cavities were prepared in the approximal surfaces of premolars, maxillary and mandibular molars. Standardized radiographs were taken at the baseline (0° horizontal and 0° vertical) and at a horizontal angulation of 10° in both mesial and distal directions. Radiographic cavity depths were measured by both conventional and digital radiographs. Results: At 0° horizontal angulation, no statistically significant differences could be determined between the results of conventionally and digitally determined radiographic depths with respect to the actual cavity depths in all premolar, maxillary, and mandibular molar groups. All conventional and digital radiographic depths at both 10° mesial and distal angulations showed statistically significant increases in depth compared to the actual cavity depths (p < 0.05), with the exception of digital radiographic depth at 10° mesial angulation for premolars. There were no statistically significant differences between conventional and digital radiographic depths for all groups. Conclusion: The present study suggests that both conventional and digital radiographs provide reproducible assessment of the depth of the approximal root cavity. But horizontal X-ray beam movements are likely to result in increase in radiographic cavity depth.

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Chromosomal Aberrations Induced by in Vitro Irradiation of $^{131}I$ ($^{131}I$의 체외 방사선조사에 의한 염색체이상)

  • Kim, Eun-Sil;Kim, Myung-Seon;Seo, Doo-Seon;Jeong, Nae-In;Rho, Seung-Ik;Lee, Jae-Yong;Kim, Chong-Soon;Han, Seung-Soo;Kim, Hee-Geun;Kang, Duck-Won;Song, Myung-Jae
    • The Korean Journal of Nuclear Medicine
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    • v.28 no.1
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    • pp.133-140
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    • 1994
  • Recently, there are many considerations and studies on biological effects of radiations in radiation workers, as well as in accidentally or therapeutically irradiated persons. The most practical and reliable method of dosimetry for radiation accidents is the scoring of gross chromosomal aberrations in human lymphocytes (Ydr) as a biological dosimetry. By the way, although usual doses of $^{131}I$ administered therapeutically for thyroid cancer are ranging from 100 mCi to 200 mCi, there are differences of absorbed doses and Ydr, ranging from 0.004 to 0.04, on equally administered $^{131}I$ due to variations in metabolic characteristics, stage of tumors and physical status of subjects. In this study, We exert to obtain the dose-response relationships of $^{131}I$, as a good guide to evaluating acute effects of accidental irradiations and radiation induced leukemia or solid tumor, by in vitro induction of chromosomal aberrations. we studied the relationship between radiation dose (D) and the frequency of chromosomal aberrations (Ydr) obserbed in peripheral lymphocytes that were irradiated in vitro with $^{131}I$ at doses ranging from 0.05 to 6.00 Gy. By scoring cells with unstable chromosomal aberrations (dicentric chromosomes and ring chromosomes) we obtained this linear-quadratic dose response equation Ydr=0.064351 $D^2$-0.13143 D+0.045684 This dose-response relationship may be useful for evaluating acute and chronic $^{131}I$ induced biological effects.

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SKIN ABSORBED DOSES FROM FULL MOUTH STANDARD INTRAORAL RADIOGRAPHY IN BISECTING ANGLE AND PARALLELING TECHNIQUES (각이등분법 및 평행법에 의한 전악 구내 표준 촬영시 두경부 피부 흡수선량 비교)

  • Kim Ae-Ji;Nah Kyung-Soo;Doh Shi-Hong;Kim Hyun-Ja;Yoo Meong-Jin
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.20 no.2
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    • pp.315-333
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    • 1990
  • This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography (l4 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator(60㎜ in diameter, 20㎝ in length) and rectangular collimator(35㎜ × 44㎜, 40㎝ in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rates of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling techniuqe, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

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Absorbed and effective dose from periapical radiography by portable intraoral x-ray machine (이동형 구내 방사선촬영기로 촬영한 치근단 방사선사진의 흡수선량 및 유효선량 평가)

  • Cho, Jeong-Yeon;Han, Won-Jeong;Kim, Eun-Kyung
    • Imaging Science in Dentistry
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    • v.37 no.3
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    • pp.149-156
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    • 2007
  • Purpose: The purpose of this study was to measure the absorbed dose and to calculate the effective dose for periapical radiography done by portable intraoral x-ray machines. Materials and Methods: 14 full mouth, upper posterior and lower posterior periapical radiographs were taken by wall-type 1 and portable type 3 intraoral x-ray machines. Thermoluminescent dosemeters were placed at 23 sites at the layers of the tissue-equivalent ART woman phantom for dosimetry. Average tissue absorbed dose and radiation weighted dose were calculated for each major anatomical site. Effective dose was calculated using 2005 ICRP tissue weighted factors. Results: On 14 full mouth periapical radiographs, the effective dose for wall-type x-ray machine was 30 Sv; for portable x-ray machines were 30 Sv, 22 Sv, 36 Sv. On upper posterior radiograph, the effective dose for wall-type x-ray machine was 4 Sv; for portable x-ray machines doses were 4 Sv, 3 Sv, 5 Sv. On lower posterior radiograph, the effective dose for wall type x-ray machine was 5 Sv; for portable x-ray machines doses were 4 Sv, 4 Sv, 5 Sv. Conclusion: Effective doses for periapical radiographs performed by portable intraoral x-ray machines were similar to doses for periapical radiographs taken by wall type intraoral x-ray machines.

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THE ACCURACY OF DIGORA SYSTEM, AN INDIRECT DIGITAL RADIOGRAPHIC SYSTEM, IN DETERMINING THE WORKING LENGTH (근관장 측정시 구내 디지털 방사선 시스템인 Digora System의 정확도에 관한 연구)

  • Han, Sang-Wook;Hang, Chan-Ui;Cho, Yong-Bum
    • Restorative Dentistry and Endodontics
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    • v.22 no.1
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    • pp.347-357
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    • 1997
  • An accurate working length is an essential factor in the success of endodontic treatment. There are several methods for determining working length; electronic apex locator, tactile sense by clinician, and radiography. Among these methods, the most commonly used method is radiography. But this method requires excessive radiation, long developing time, and many equipments. In additon, it could give an image distortion and two dimensional image. To improve these disadvantages, an intraoral digital radiographic system (Digora$^{(R)}$) which use an imaging plate instead of a film, was developed. The purpose of this investigation was to compare Digora imaging with conventional radiography in determining the working length. Maxillary first or second molars of human dried skull were used. Files were inserted into canals at randomly selected lengths, from 2mm short of the radiographic apex to 2rnm beyond. Radiographs and Digora images(Digora positive and Digora negative) were evaluated to determine the adjustment needed to place the file 0.5mm from the radiographic apex. The results were as follows ; 1. There was no significant difference in accuracy between those evaluated in ${\pm}0.5mm$ and those accurately evaluated in the 3 images. 2. When comparing the accuracy of each image without distinguishing the 3 images, in the group accurately determined within ${\pm}0.5mm$, the mesiobuccal group showed significantly higher accuracy compared to the palatal group(p<0.05).

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Zygoma-gear appliance for intraoral upper molar distalization (Zygoma-gear를 이용한 구치부 후방이동을 통한 비발치 치험례)

  • Nur, Metin;Bayram, Mehmet;Pampu, Alper
    • The korean journal of orthodontics
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    • v.40 no.3
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    • pp.195-206
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    • 2010
  • The aim of this report is to present an intraoral upper molar distalization system supported with zygomatic anchorage plates (Zygoma-gear Appliance, ZGA). This system was used for a 16-year-old female patient with a Class II molar relationship requiring molar distalization. The system consisted of bilateral zygomatic anchorage plates, an inner-bow and heavy intraoral elastics. Distalization of the upper molars was achieved in 3 months and the treatment results were evaluated from lateral cephalometric radiographs. According to the results of the cephalometric analysis, the maxillary first molars showed a distalization of 4 mm, associated with a distal axial inclination of $4.5^{\circ}$. The results of this study show that an effective upper molar distalization without anchorage loss can be achieved in a short time using the ZGA. We suggest that this new system may be used in cases requiring molar distalization in place of extraoral appliances.

COMPARISON BETWEEN INTRAORAL AND PANORAMIC RADIOGRAPHS IN THE EVALUATION OF ALVEOLAR BONE LOSS (치조골소실의 평가에 있어서 구내 X선사진과 파노라마 X선사진의 비교)

  • Park Mi-Kyung;Choi Karp-Shik
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.23 no.2
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    • pp.265-275
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    • 1993
  • The purpose of this study was to compare the interpretation results of the panoramic radiographs with those of intraoral radiographs in evaluation of alveolar bone loss. All radiographs were obtained from 100 patients who had visited the Dental Infirmary of Kyungpook National University Hospital for periodontal state evaluation. The results were as follows: The percentages of interpretable sites were 95.9%(94.6% in maxilla, 97.4% in mandible) on the intraoral radiographs, and 90.7%(84.0% in maxilla, 97.3% in mandible) on the panoramic radiographs. The concordance of interpretation scores of marginal bone loss between intraoral and panoramic radiographs was 66.3%(65.6% in maxilla, 66.8% in mandible). And according to the site, the highest concordance was in the distal surface of the mandibular 2nd premolar at 82.0%, and the distal surface of the mandibular 1st premolar(76.8%), the distal surface of the maxillary central incisor(75.8%), the mesial surface of the 2nd premolar (75.0%) in descending order of frequency. According to the interpretation scores of the marginal bone loss, the percentages of concordance between intraoral and panoramic radiographs were the highest on the score 10 at 76.4%, and the lowest on the score 8, 9. And the percentages of concordance were inverse proportional rate from the score 5 to the score 9. Number of the observed sites of the furcation involvement in bitewing and panoramic radiographs were 268 sites, and the percentage of interpretable sites was 92.9% in bitewing radiographs and 86.6% in panoramic radiographs. And the concordance rate of interpretation was 79.5%.

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Detection method of proximal caries using line profile in digital intra-oral radiography (디지털 구내방사선사진에서 라인 프로파일을 이용한 인접면우증식의 인지 방법)

  • Park, Jeong-Hoon;Choi, Yong-Suk;Kim, Gyu-Tae;Hwang, Eui-Hwan;Lee, Gi-Ja;Choi, Sam-Jin;Park, Hun-Kuk
    • Imaging Science in Dentistry
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    • v.39 no.4
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    • pp.185-189
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    • 2009
  • Purpose : The purpose of this study was to investigate how to detect proximal caries using line profile and validate linear measurements of proximal caries lesions by basic digital manipulation of radiographic images. Materials and Methods : The X-ray images of control group (15) and caries teeth (15) from patients were used. For each image, the line profile at the proximal caries-susceptible zone was calculated. To evaluate the contrast as a function of line profile to detect proximal caries, a difference coefficient (D) that indicates the relative difference between caries and sound dentin or intact enamel was measured. Results : Mean values of D were $0.0354{\pm}0.0155$ in non-caries and $0.2632{\pm}0.0982$ in caries (p<0.001). Conclusion : The mean values of caries group were higher than non-caries group and there was correlation between proximal dental caries and D. It is demonstrated that the mean value of D from caries group was higher than that of control group. From the result, values of D possess great potentiality as a new detection parameter for proximal dental caries.

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Measurement of Radon Daughters in Airborne Dust (공기부유진내(空氣浮游塵內)의 Radon 붕괴생성물(崩壞生成物)의 농도측정(濃度測定))

  • Kim, Pill-Soo;Min, Duck-Kee;Ro, Seung-Gy
    • Journal of Radiation Protection and Research
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    • v.2 no.1
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    • pp.9-16
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    • 1977
  • A simple method has been established for determining RaA, RaB and RaC concentrations in airborne dust. This is to evaluate the concentration from measurement of total alpha activities in three selected-time intervals after an air sample is taken from the membrane filter paper (mean pore size: $0.8{\mu}m$). As a preliminary trial, a time-variation of the concentrations has been determined using the single-filter method at the KAERI site (N. Lat. $37^{\circ}38'$ and E. Long $127^{\circ}15'$), Seoul, Korea. It appears that there is a large variation of the concentrations depending on the sampling time. Generally the highest value was observed in the morning that may coincide with the highest density of atmosphere in a day while the lowest value was obtained around fourteen o'clock.

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