• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.6
• /
• pp.538-544
• /
• 2000

A phased array ultrasonic nondestructive inspection system is being developed to obtain images of the interior of steel structures by modifying a medical ultrasound imaging system. The medical system consists of 64 individual transceiver channels that can drive 128 array elements. Several modifications of the system were required mainly due to the change of sound speed. It was necessary to fabricate array transducers for steel structure and to obtain A-scan signal that is necessary for the nondestructive testing. Boundary diffraction wave model was used for the prediction of radiation beam field from array transducers, which provided guidelines to design array transducers. And a RF data acquisition board was fabricated for the A-scan signal acquisition along a selected un line within an image. For the proper beam forming in the transmission and reception for steel structure, delay time was controlled. To demonstrate the performance of the developed system and fabricated transducers, images of artificial specimens and A-scan signals for selected scan lines were obtained in a real time fashion.

• Korean Journal of Optics and Photonics
• /
• v.31 no.1
• /
• pp.1-6
• /
• 2020

The chest wall, an organ directly affected by environmental particles through respiration, consists of ribs, a pleural layer and intercostal muscles. To diagnose early and treat disease in this body part, it is important to visualize the details of the chest wall, but the structure of the pleural layer cannot be seen by chest computed tomography or ultrasound. On the other hand, optical coherence tomography (OCT), with a high spatial resolution, is suited to observe pleural-layer response to talc, one of the fine materials. However, intensity-based OCT is weak in providing information to distinguish the detailed structure of the chest wall, and cannot distinguish the reaction of the pleural layer from the change in the muscle by the talc. Polarization-sensitive OCT (PS-OCT) takes advantage of the fact that specific tissues like muscle, which have optical birefringence, change the backscattered light's polarization state. Moreover, the birefringence of muscle associated with the arrangement of myofilaments indicates the muscle's condition, by measuring retardation change. The PS-OCT image is interpreted from three major perspectives for talc-exposure chest-wall imaging: a thickened pleural layer, a separation between pleural layer and muscle, and a phase-retardation measurement around lesions. In this paper, a rabbit chest wall after talc pleurodesis is investigated by PS-OCT. The PS-OCT images visualize the pleural layer and muscle, respectively, and this system shows different birefringence of normal and damaged lesions. Also, an analyisis based on phase-retardation slope supports results from the PS-OCT image and histology.

• Physical Therapy Rehabilitation Science
• /
• v.5 no.4
• /
• pp.210-214
• /
• 2016

Objective: The aim of this study was to measure the muscle architectural parameters of abdominal muscles in healthy individuals by rehabilitative ultrasound imaging (RUSI) and to investigate their changes after bridging exercise in various environments. Design: Cross-sectional study. Methods: The study included 40 healthy participants (19 men, 21 women). Subjects were randomly allocated to a stable surface group (SG, n=20) or an unstable surface group (UG, n=20). The participants assumed three positions in rest, bridging exercise with knee flexion $60^{\circ}$, and bridging exercise with knee flexion $90^{\circ}$ for the measurement of abdominal muscle thickness by RUSI. For the resting position, the participants held the head neutral in a hook-lying position and the dominant side was measured. For contraction, the participants performed the bridging exercise with the knee joint in $60^{\circ}$ and $90^{\circ}$ of flexion for 10 seconds each. Results: For transversus abdominis, external oblique muscle thickness, within the stable surface group and the unstable surface group, no significant contraction difference was observed in both the $60^{\circ}$ and $90^{\circ}$ bridge exercise conditions. Contraction difference of internal oblique muscle was significantly larger at $90^{\circ}$ than at $60^{\circ}$ within the SG (p<0.05). But within the UG, no significant contraction difference was shown. There was no significant contraction difference between the surface group and the unstable SG at $60^{\circ}$ condition and at $90^{\circ}$ condition in all measured muscles. Conclusions: The contraction difference is different for each muscle during bridge exercise with knee flexion $60^{\circ}$ and bridging exercise with knee flexion $90^{\circ}$. Muscle contraction difference is generally large when exercised on an unstable surface than a stable surface, but these are not statistically significant when bridging exercise is performed using dynamic air cushion for unstable surface.

• Korean Journal of Head & Neck Oncology
• /
• v.16 no.1
• /
• pp.64-68
• /
• 2000

Objectives: With the recent advances and increasing use of imaging techniques in examination of the neck, the incidence of incidentally discovered thyroid carcinoma has been increasing. This study was carried out to evaluate the clinicopathologic characteristics of incidental thyroid carcinomas and to find optimal therapeutic strategies for these lesions. Materials & Methods: From Jan. 1988 to Aug. 1998, 1,053 patients were operated on for thyroid cancer, of whom 127(12.1%) had incidentally discovered thyroid cancers which were identified during routine health checkups(n=40), diagnostic procedures for unrelated medical conditions(n=39) and mass screening for thyroid cancer(n=48). The preoperative diagnosis was obtained by ultrasound-guided FNAB and the extent of surgery was determined based on frozen section examinations, as well as prognostic factors and gross findings at the time of surgery. Results: There were 6 men and 121 women with a mean age of 45.9 years. Histopathological diagnosis included papillary carcinomas(n=1l9), follicular carcinomas(n=6), poorly differentiated carcinoma(n=l) and medullary carcinoma(n=1). Thirty patients(23.6%) had multifocallesions. The mean diameter of the tumors was 1.1 cm(0.2-3.4 cm). Capsular invasions were found in 53 patients(41.7%) and nodal metastases in 41(32.3%). The surgical procedures used were: 90 less-than total thyroidectomies and 37 total thyroidectomies with central neck node dissection. Lateral neck dissection was added in 5 patients. According to TNM staging, 79 patients(63.2%) were at stage I, 15(12.0%) at stage II, 31(24.8%) at stage III and 0(0.0%) at stage IV. By AMES scoring system, 102 patients(81.6%) were in the low-risk group and 23(18.4%) in the high-risk group. And by MACIS scoring system, 103(86.6%) of 119 papillary thyroid cancer patients were less than 6. Conclusions: The clinicopathological characteristics of incidentally discovered thyroid carcinomas are similar to ordinary thyroid carcinomas. The treatment of choice should be individualized based on the particular clinical situation encountered, as in ordinary thyroid carcinomas.

• Pediatric Infection and Vaccine
• /
• v.14 no.2
• /
• pp.129-135
• /
• 2007

Purpose : Kikuchi disease is a subacute necrotizing lymphadenitis characterized by fever, cervical lymphadenopathy and benign self-limiting course in young women especially, but rare in children. Their etiopathology is still unknown, but involved viruses and autoimmune mechanism were proposed. We investigated the clinical and laboratory characteristics of Kikuchi disease in children. Methods : Five patients were diagnosed of Kikuchi disease from January 2001 to June 2006 in Kyunghee University Hospital. We reviewed their medical records retrospectively and analyzed clinical and laboratory findings. Results : The mean age of 5 patients (male to female ratio; 2:3) was 9 yr 9 mon(range: 8 yr 2 mon-12 yr 6 mon). The chief complaints were sustained fever and cervical lymph node that was unilateral, tender and swollen. All patients were treated with antibiotics before diagnosis was made, and rash developed in 2 patients. One patient showed necrotic change in ultrasound with which we suspected Kikuchi disease. Three patients were examined by CT scan additionally. The interval between admission and cervical lymph node excisional biopsy ranged from 6 days to 15 days, and mean period was 9.6 days. All pathological findings were compatible to necrotizing lymphandenitis. Conclusion : Unnecessary laboratory and imaging studies, and treatment with antibiotics tend to be done before making diagnosis, and that caused prolonged hospitalization. Therefore we studied the clinical and laboratory characteristics of Kikuchi disease in children.

• Journal of Yeungnam Medical Science
• /
• v.10 no.1
• /
• pp.127-134
• /
• 1993

Percutaneous needle biopsy of pulmonary lesion with use of fluoroscopic guidance is well established as a diagnostic tool but limited by the small size and inaccessibility of certain lesions. However, percutaneous needle biopsy has been used increasingly in relation to advance and the safty of smaller biopsy needle and new imaging modalities such as ultrasound and CT. CT, because of its characteristics of high resolution, allows tissue sampling with considerable safety from area that heretofore could not be visualized under fluoroscopy. The authors summarized 44 pulmonary lesions that underwent CT-guided transthoracic biopsy with fine-needle over a 14 month period and analyzed the sensitivity of PTNB. CT-guided PTNB was done with 20 gauge or 22 gauge Westcott biopoy needle(Manan medical products, USA). A diagnosis was made in 27 of 44 cases(61%) including malignany in 19 of 24 cases and benignancy in 8 of 20 cases. The pulmonary mass lesions were located at the peripheral zone of the lung field in 33 cases and at the central zone in 11 cases. Complications were observed in 2 cases which were pneumothorax and hemoptysis each but specific therapy was not required. The sensitivity of PTNB by one session was 61%(27/44). The sensitivity of malignancy was 79%(19/24) and benignancy was 40%(8/20). These results suggest the usefulness of PTNB using fine needles be increased in earlier diagnosis and improved staging of pulmonary nodular lesions without significant complications.

• Radiation Oncology Journal
• /
• v.26 no.2
• /
• pp.96-103
• /
• 2008

Purpose: To conduct a nationwide academic hospital patterns of the practice status and principles of radiotherapy for prostate cancer. The survey will help develop the framework of a database of Korean in Patterns of Case Study. Materials and Methods: A questionnaire about radiation treatment status and principles was sent to radiation oncologists in charge of prostate cancer treatment at thirteen academic hospitals in Korea. The data was analyzed to find treatment principles among the radiation oncologists when treating prostate cancer. Results: The number of patients with prostate cancer and treated with radiation ranged from 60 to 150 per academic hospital in Seoul City and 10 to 15 outside of Seoul City in 2006. The primary diagnostic methods of prostate cancer included the ultrasound guided biopsy on 6 to 12 prostate sites(mean=9), followed by magnetic resonance imaging and a whole body bone scan. Internal and external immobilizations were used in 61.5% and 76.9%, respectively, with diverse radiation targets. Whole pelvis radiation therapy(dose ranging from 45.0 to 50.4 Gy) was performed in 76.9%, followed by the irradiation of seminal vesicles($54.0{\sim}73.8$ Gy) in 92.3%. The definitive radiotherapy doses were increased as a function of risk group, but the range of radiation doses was wide(60.0 to 78.5 Gy). Intensity modulated radiation therapy using doses greater than 70 Gy, were performed in 53.8% of academic hospitals. In addition, the simultaneous intra-factional boost(SIB) technique was used in three hospitals; however, the target volume and radiation dose were diverse. Radiation therapy to biochemical recurrence after a radical prostatectomy was performed in 84.6%; however, the radiation dose was variable and the radiation field ranged from whole pelvis to prostate bed. Conclusion: The results of this study suggest that a nationwide Korean Patterns of Care Study is necessary for the recommendation of radiation therapy guidelines of prostate cancer.