• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.2
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• pp.171-181
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• 2009

The objective of this study was to analyse stress distribution of maxillary complex by use of face mask. The construction of the three-dimensional FEM model was based on the computed tomography(CT) scans of 13.5 years-old male subject. The CT image were digitized and converted to the finite element model by using the mimics program, with PATRAN. An anteriorly directed force of 500g was applied at the first premolar 45 degrees downwards to the FH plane and at the first molar 20 degrees downwards to the FH plane. When 45 degrees force was applied at maxillary first premolar, there were observed expansion at molar part and constriction at premolar part. The largest displacement was 0.00011mm in the x-axis. In the y-axis, anterior displacement observed generally 0.00030mm at maximum. In the z-axis, maxillary complex was displaced 0.00036 mm forward and downward. When 20 degrees force was applied at maxilla first molar, there were observed expansion at lateral nasal wall and constriction at molar part. The largest displacement was 0.001mm in the X-axis. In the Y-axis, anterior displacement observed generally 0.004mm at maximum. In the Z-axis, ANS was displaced upward and pterygoid complex was displaced downward. The largest displacement was 0.002mm.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.30-38
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• 2001

Background: The purpose of this study was to evaluate the usefulness of diffusion-weighted magnetic resonance imaging for monitoring the response to radiation therapy in metastatic bone marrow of the spines. Materials and Methods: Twenty-one patients with metastatic bone marrow of the spines were examined with MRI. Diffusion-weighted and spin-echo MRI were performed in 10 patients before and after radiation therapy with or without systemic chemotherapy, and performed in 11 patients after radiation therapy alone. Follow up spin-echo and diffusion-weighted MRI were obtained at 1 to 6 months after radiation therapy according to patients' condition. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the metastatic bone marrows before and after radiation therapy on conventional spin-echo sequence MRI and diffusion-weighted MRI were evaluated. Bone marrow contrast ratios and signal-to-noise ratios before and after radiation therapy of diffusion- weighted MRI were analyzed. Results: All metastatic bone marrow of the spinal bodies were hyperintense to normal bone marrow of the spinal bodies on pretreatment diffusion-weighted MRI and positive bone marrow contrast ratios(p<0.001), and hypointense to normal spinal bodies on posttreatment diffusion-weighted MRI and negative bone marrow contrast ratios(p<0.001). The signal to noise ratios after treatment decreased comparing with those of pretreatment. Decreased signal intensity of the metastatic bone marrows on diffusion-weighted MRI began to be observed at average more than one month after the initiation of the radiation therapy. Conclusion: These results suggest that diffusion-weighted MRI would be an excellent method for monitoring the response to therapy of metastatic bone marrow of the spinal bodies, however, must be investigated in a larger series of patients with longer follow up period.

• Journal of Yeungnam Medical Science
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• v.20 no.1
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• pp.71-78
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• 2003

Unilateral absence of a pulmonary artery (UAPA) is a rare congenital anomaly that is frequently associated with other cardiovascular anomalies first reported by Fraentzel in 1968. Most patients who have no associated cardiac anomalies have only minor or absent symptoms. We experienced a case of isolated UAPA in a young female presenting hemoptysis. The chest radiograph showed a small left lung volume and high resolutional CT of chest showed multiple subpleural nodules and centrilobular nodules in parenchyma. The video-assisted thoracoscopic biopsy revealed diffuse dilated vessels in visceral pleura. The pulmonary angiogram confirmed the absence of the left main pulmonary artery.

• Tuberculosis and Respiratory Diseases
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• v.40 no.1
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• pp.58-66
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• 1993

Mucoepidermoid carcinoma of the lung can be divided into low grade and high grade varieties, like their major salivary glands counterparts. This carcinoma comprises only. about 0.5% of all pulmonary neoplasma. Their clinical and biologic behaviors are closely related with histologic grade of carcinoma. We have experienced two cases of mucoepidermoid carcinoma. Case 1 occurred in a 16 years old male and showed the histologic features of low grade type. This carcinoma arised from the right upper lobe bronchus which was removed by the right upper lobectomy. Case 2 occurred in a 41 year old male was the high grade carcinoma located at the distal left main bronchus which was removed by the left pnemonectomy.

• Journal of the Korean Society of Radiology
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• v.9 no.5
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• pp.279-285
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• 2015

The eye of human is a radiation sensitive organ and this organ should be shielded from radiation exposure during brain CT procedures. In the brain CT procedures, bismuth protector using to reduce the radiation exposure dose for eye. But protecting the bismuth always accompanies problem of the image quality reduction including artifact. This study aim is the eye radiation exposure dose and image quality evaluation of the new tube current modulation such as new organ based-tube current modulation, longitudinal-TCM, angular-TCM between shielding scan technique using bismuth and lead glasses. As a result, radiation dose of eye is reduced 25.88% in new OB TCM technique then reference scan technique and SNR new OB TCM is 6.05 higher than bismuth shielding scan technique and lower than reference scan technique. In clinical brain CT, new OB TCM technique will contribute to reduction of radiation dose for eye without decrease of image quality.

• Journal of Trauma and Injury
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• v.25 no.4
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• pp.122-131
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• 2012

Purpose: Diffuse axonal injury (DAI) is clinically defined as a coma of over six hours in a head trauma victim without a focal mass lesion. The emergency physician usually resuscitates and stabilizes a comatose head trauma victim in the emergency Department. After assessment and treatment, the prognosis is very important to both the victim and the physician. The prognosis for DAI is based on Glasgow Coma Scale (GCS) and other imaging data. We investigated the prognostic value of computed tomography (CT) and gradient-echo magnetic resonance imaging (GRI) for head trauma victims with DAI. Methods: Fifty-three(53) head trauma victims of DAI were enrolled in this study from 2007 to 2012. During the study period of six years, data on trauma victims were collected retrospectively. We analyzed the differences in the Glasgow Outcome Scale (GOS) result between the CT and the GRI modalities. Results: We classified the study group by using GOS. Between the good outcome subgroup (GOS scores of 4 and 5) and the poor outcome subgroup (GOS score of 1-3), there were no statistical difference in sex, age, initial vital signs and initial GCS score. The good outcome subgroup had non-hemorrhage on CT(52%), which was correlated with good outcome and a shorter awakening time, while a larger number and a deeper location of hemorrhagic lesions on in GRI were correlated with poor outcome in DAI. Conclusion: We conclude that the existence of hemorrhagic lesions on CT, and the number and location of those lesions on GRI had good prognostic value for head trauma victims with DAI.

• Journal of Oral Medicine and Pain
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• v.33 no.4
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• pp.395-399
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• 2008

Orofacial pain and limited range of mouth opening as symptoms of temporomandibular disorder are mainly triggered by the structural and/or functional changes of temporomandibular joint and related structure itself. But careful diagnostic evaluation should be needed because they may be occurred by another pathologic conditions such as neoplasm in head and neck region. If there would be atypical pain characteristics or clinical features, systemic comorbid symptoms, or poor response to treatment, advanced imaging modalities such as CT or MRI will be mandatory for differential diagnosis. We experienced the case which was diagnosed as nasopharyngeal cancer mimicking temporomandibular disorder, and reviewed clinical considerations for proper differential diagnosis.

• Advances in pediatric surgery
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• v.11 no.2
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• pp.180-185
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• 2005

Superior mesenteric artery (SMA) syndrome is a rare disorder caused by extrinsic compression of the third portion of the duodenum by the SMA. The operative treatment of choice is bypassing the obstructed duodenal segment by duodenojejunostomy. We report one case of SMA syndrome treated by laparoscopic duodenojejunostomy and followed up by 3D-reconstructive CT scan. A fifteen-year-old boy with intermittent vomiting and weight loss was admitted. Ultrasonography showed narrowing of the distance between the SMA and aorta. Hypotonic duodenography showed dilatation of duodenal third portion and barium stasis. On 3Dreconstructive CT scan, the angle between SMA and aorta was $37^{\circ}$. The postoperative course was uneventful. Three months later, he had gained 3 kg of weight and the angle between SMA and aorta increased to $38-39^{\circ}$ on 3D reconstructive CT scan. Laparoscopic duodenojejunostomy for bypassing the obstructive duodenum in SMA syndrome is a feasible and safe method.

• Imaging Science in Dentistry
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• v.37 no.2
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• pp.87-92
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• 2007

Purpose: To measure the absorbed doses of cone beam computed tomography (CBCT), which is recently being more frequently used, and to compare them with those of panoramic radiography. Materials and Methods: To measure the absorbed doses of CBCT ($PSR-9000N^{TM}$, Asahi Roentgen Ind. Co., Japan), we placed TLD chips on the skin regions above the parotid and thyroid glands, and on the dorsum of tongue in a dental head phantom. We used two image acquisition modes of the Dental and Panoramic modes of CBCT, which differed in the field of view. Also, panoramic radiographs (Auto IIIN, Asahi Roentgen Ind. Co., Japan) were taken to compare with the absorbed doses of CBCT. Result: In the Dental mode of CBCT, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 3.53, 3.13, and 0.36 mGy, respectively. In the Panoramic mode of CBCT, they were 9.57, 9.15, and 0.85 mGy, respectively. The panoramic mode showed higher absorbed doses than those of the Dental mode. In the panoramic radiography, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 1.21, 1.19, and 0.16 mGy, respectively. And they were about 1/3 of the Dental mode and 1/9 of the Panoramic mode of CBCT. Conclusion: Absorbed doses of CBCT are higher than those of panoramic radiography, and dependent upon the field of view.

• Journal of radiological science and technology
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• v.45 no.3
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• pp.213-223
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• 2022

Although the number of computed tomography(CT) is increasing every year, it is insufficient to establish appropriate workload calculation standards of radiologic technologist to provide optimal medical services to patients, such as patient safety management and infection management. The purpose of this study is to present guidelines for calculating the appropriate workload of radiologic technologist by analyzing the work flow of CT procedures and the time required for CT examination in major hospitals. As for the study subjects and methods, the appropriate process for each step of CT examination was investigated to systematically present the process and time required for the actual examination, and the CT procedure time of 104,105 adult patients and 465 pediatric patients under the age of 6 were analyzed. For the time required, data according to the use of contrast medium, procedure type, and adult/child were collected and compared. The test time of CT examination using contrast medium took about 13 minutes when one radiologic technologist worked and about 9 minutes when two radiologic technologists worked. The time required for the procedures were statistically significant depending on the presence or absence of contrast medium, multi-phase procedure, and patient age (considering pediatric patients). As a result, in order to thoroughly perform patient safety and infection management, the appropriate workload increased by about 40% when there were two radiologic technologists. The limit workload was an average of 32 people per day with one radiologic technologist per 15 minutes, and 48 people per day with two radiologic technologist per 10 minutes. This is a marginal workload, and in the case of procedures that require more time to acquire radiographic images, the interval between reservations should be widened.