• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.248-261
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• 1999

In order to define a current set of Korean children norm with mixed dentition, following study was done. The subjects were 102 healthy dentition contestants(48boys, 54girls). Standardized lateral head roentgenograms were taken, and Ricketts analysis was done. Results were as follows: 1. Length of anterior cranial base, posterior facial height, corpus length were longer in male than in female(p<0.05), and Porion was located posteriorly in male than in female(p<0.01). 2. Through facial depth, Pogonion of male was more forwardly positioned(p<0.05), mandible was significantly steeper in female, and maxillary anterior teeth were significantly tipped forward in male(p<0.05). 3. Variables such as length of anterior cranial base, upper molar position(p<0.01) and corpus length(p<0.05) were significantly changed by age. 4. Maxillary height, facial depth, mandibular plane angle, convexity were changed by age, but not significantly(p>0.05).

• Progress in Medical Physics
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• v.14 no.2
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• pp.90-98
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• 2003

Purpose : A new virtual simulation technique for craniospinal irradiation (CSI) that uses a CT-simulator was developed to improve the accuracy of field and shielding placement as well as patient positioning. Materials and Methods : A CT simulator (CT-SIM) and a 3-D conformal radiation treatment planning system (3D-CRT) were used to develop CSI. The head and neck were immobilized with a thermoplastic mask while the rest of the body was immobilized with a Vac-Loc. A volumetric image was then obtained with the CT simulator. In order to improve the reproducibility of the setup, datum lines and points were marked on the head and body. Virtual fluoroscopy was performed with the removal of visual obstacles, such as the treatment table or immobilization devices. After virtual simulation, the treatment isocenters of each field were marked on the body and on the immobilization devices at the conventional simulation room. Each treatment fields was confirmed by comparing the fluoroscopy images with the digitally reconstructed radiography (DRR) and digitally composited radiography (DCR) images from virtual simulation. Port verification films from the first treatment were also compared with the DRR/DCR images for geometric verification. Results : We successfully performed virtual simulations on 11 CSI patients by CT-SIM. It took less than 20 minutes to affix the immobilization devices and to obtain the volumetric images of the entire body. In the absence of the patient, virtual simulation of all fields took 20 min. The DRRs were in agreement with simulation films to within 5 mm. This not only reducee inconveniences to the patients, but also eliminated position-shift variables attendant during the long conventional simulation process. In addition, by obtaining CT volumetric image, critical organs, such as the eyes and the spinal cord, were better defined, and the accuracy of the port designs and shielding was improved. Differences between the DRRs and the portal films were less than 3 m in the vertebral contour. Conclusion : Our analysis showed that CT simulation of craniospinal fields was accurate. In addition, CT simulation reduced the duration of the patient's immobility. During the planning process. This technique can improve accuracy in field placement and shielding by using three-dimensional CT-aided localization of critical and target structures. Overall, it has improved staff efficiency and resource utilization by standard protocol for craniospinal irradiation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.7-14
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• 1976

This study was done using the 45° oblique lateral old, 18 males and 27 females, with normal occlusion, premolars and molars on upper and lower jaws. Axial inclination to nasal floor, occlusal plane and inter-axial inclination were examined. In addition the position of each tooth was examined in height and depth in upper and lower jaws. The results were obtained as follows; 1. The inclination of long axis of upper 1st premolar was most nearly perpendicular, upper canine was tilted mesially, and 2nd premolar and molars were tilted distally. 2. The inclination of long axis of lowers molar were tilted mesially. 3. There were no severe variation on the inter-axial inclination of canine to mandibular plane, and 2nd molar.

• Journal of radiological science and technology
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• v.3 no.1
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• pp.21-27
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• 1980

It is the experimental report by using 17cm, 19cm in thickness water-phantom to investigate optimum tube voltage in taking skull roentgenography. The obtained results are as follows: 1. An adequate kVp for P-A projection is range from 80-90. 2. An adequate kVp for lateral projection is range from 75-85.

• The korean journal of orthodontics
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• v.40 no.6
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• pp.421-431
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• 2010

Objective: This study aimed to verify the intra-individual reproducibility of the natural head position (NHP) in adult Korean patients in the centric relation (CR) position and to prove the inter-individual variability of the Frankfurt horizontal (FH) plane and sella-nasion (SN) line compared to the true horizontal line (THL). In addition, the study aimed to investigate the correlations between linear measurements from A-point and B-point to the nasion true vertical line (NTVL) and angular measurements from A-point and B-point to the SN line. Methods: Two lateral cephalograms were taken of 116 subjects (23 males, 93 females) with CR wax bites in a NHP at a one-week interval. Results: Method errors of three variables and intraclass correlation coefficients of six parameters proved the intra-individual reproducibility of NHP (p < 0.001). The angle of the FH to the THL was not significantly different from $0^{\circ}$ (p > 0.05), but it was clinically variable (SD $3.89^{\circ}$) on the inter-individual level. Conversely, the angle of the SN line to the THL was significantly different from $7^{\circ}$ (p < 0.05). Very low correlation was found between the linear measurements and angular measurements of A-point and B-point (p < 0.01). Conclusions: The NTVL could be a useful reference line for assessing the antero-posterior position of the maxilla and mandible of Korean adult patients in NHP and CR.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.707-720
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• 1999

The purpose of this study was to evaluate racial differences In head posture and the influence of head posture to the craniofacial morphology. The sample group of this study was made up of 51 Korean males and 120 Scandinavian Caucasian males. From the comparison of the cranio-cervical angle and the variables of craniofacial morphology between them, the following results were obtained. 1. The cranio-cervical angle (NSL/OPT) was on average 9.28 degrees larger In Koreans. 2. The length of the anterior cranial base (N-S) was on average 4.66mm shorter in Koreans. 3. The length of the maxillary base (sp-pm and ss-pm) were on average 2.75mm and 4.65mm shorter in Koreans respectively, the anterior maxillary height (n-sp) was on average 2.60mm longer, the posterior dimension (s-pm) was found to be 2.06mm longer in Koreans, and the maxillary inclination (NSL/NL) was identical in both samples. 4. The mandibular body length (pg-tgo) and ramus height (ar-tgo) were identical in the two groups, but the genial angle (ML/RL) was 3.22 degrees smaller and the mandibular plane inclination (NSL/ML) was 2.44 degrees larger in Koreans 5. The maxillary prognathism (s-n-sp and s-n-ss) and the mandibular prognathism (s-n-sm) were identical in both samples. 6. The sagittal jaw relationship (ss-n-pg) was 1.44 degrees larger in the Korean sample, but the vortical jaw relationship (NL/ML) was not significantly different. 7. The anterior facial height (n-gn) was 5.57mm longer in the Korean sample. 8. The mandibular alveolar prognathism (CL/ML) was 5.71 degrees greater and the interincisal angle (ILs/ILi) was 3.08 degrees more acute in Koreans. Taken together these results, craniofacial morphology can be influenced by the head posture defined by cranio-cervical angulation.

• Journal of Oral Medicine and Pain
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• v.38 no.2
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• pp.203-213
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• 2013

Objecives : The purpose of the study was to evaluate treatment outcome of mandibular advancement device(MAD) in obstructive sleep apnea (OSA) patients using full night polysomnography and cephalometry. Methods : Twenty-seven OSA patients were confirmed by full night, lab-attended polysomnography. Cephalometric examinations were conducted to obtain SNA, ANB, $AH{\bot}MP$, AH-C3, SPT, PNS-U, NAS, SOAS, MOAS, and HAS. Mandibular advancement devices (MADs) were fabricated and delivered for all subjects. After acclimation period of MAD, the second polysomnographic examinations were conducted in the same manner. Polysomnographic variables were compared between before and after MAD placement. Also, correlation coefficients were calculated between apnea-hypopnea index (AHI) and each item of cephalometric parameters. Results : There were significant improvements in total AHI, lowest $SpO_2$, and total arousal index after MAD therapy. Also, there were significant improvements in NREM $SpO_2$ and NREM AHI, but not in REM $SpO_2$ and REM AHI with MAD. Stratifying the sleep stage, there were significant decrease in stage I and significant increases in stage II and REM, but change in stage III was not significant. SNA and SOAS were significantly correlated with total AHI and NAS was significantly correlated with supine AHI. ANB was significantly associate with the effect of MAD. Conclusions : MAD is an effective treatment in OSA patients comparing polysomnographic variables before and after treatment. Cephalometric examination can be useful to evaluate OSA patients and predict treatment outcome of MAD.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.941-946
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• 2019

Computed tomography (CT) has been increasing in frequency and indications for use in clinical diagnosis and treatment decisions. Multidetector CT has the advantage of shortening the inspection time and obtaining a high resolution image compared to a single detector CT, but has been pointed out the disadvantage of increasing the radiation exposure. In addition, when the low tube voltage is used to reduce the exposure dose in the CT, noise increases relatively. In the existing method, the method of finding the optimal image quality using the method of adjusting the parameters of the image reconstruction method is not a fundamental measure. In this study, we applied a double-tree complex wavelet algorithm and analyzed the results to maintain the normal signal and remove only noise. Experimental results show that the noise is reduced from 8.53 to 4.51 when using a complex oriented 2D method with 100kVp and 0.5sec rotation time. Through this study, it was possible to remove the noise and reduce the patient dose by using the optimal noise reduction algorithm. The results of this study can be used to reduce the exposure of patients due to the low dose of CT.

• Journal of Veterinary Clinics
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• v.26 no.1
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• pp.109-112
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• 2009

A three-week old female Chihuahua dog weighing 80 g was presented with the absence of skull palpation, suckling disability, and growth retardation. Physical examination revealed asymmetry of the lips slanting to the left side when feeding milk. Also there were head tilt to the left side and corneal ulcer of the left eye. The absence of the frontal and parietal bones were shown on radiographs. Lateral ventricular enlargement was identified on the ultrasonographic examination. On computed tomographs, frontal and parietal bone defect, ventricle enlargement, and intracranial arachnoid cyst were observed. The dog was dead after 1 day of presentation. The dog was diagnosed as the primary acalvaria by necropsy.

• Journal of Veterinary Clinics
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• v.27 no.4
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• pp.450-452
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• 2010

A 4-year-old male Yorkshire terrier was referred to us with signs of vomiting and unconsciousness due to a blunt head trauma. Gross examinations detected facial edema, subcutaneous hemorrhage and hypersalivation. A survey radiograph located an occipital fragment which was displaced caudally. A three-dimensional computed tomographic reconstruction demonstrated that the ventral portion of the fragment was attached incompletely. Because of the instability of the fragment, it was decided to perform an esquillectomy. After removing the fragment, the defect was reinforced with a muscular flap originating from the splenius muscle. The patient's condition gradually improved except for a slightly ataxic gait. At 20 months follow-up, there was no evidence of ataxia. The neurological status did not deteriorate before starting surgical intervention, although the patient sustained a skull fracture with severe intracranial hemorrhage. It is likely that the fragment being displaced outwardly played an important role in preventing an increase in intracranial pressure which could have led to neurological deterioration.