• Journal of Korean Neurosurgical Society
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• v.30 no.7
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• pp.876-882
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• 2001

Objectives : Meningeal hemangiopericytoma is a rare tumor. Clinical and radiological features are similar to those of an ordinary meningioma. But its biological behavior is quite different from those of a meningioma as it brings profuse bleeding in the operation field, frequent recurrence and metastasis to other systemic organs even in the case of gross total resection. In order to find out the prognostic factors and to compare longterm outcome after various treatment modalities, the authors reviewed consecutive 20 operated cases of meningeal hemangiopericytoma to characterize their clinical features, surgical outcomes and effectiveness of the radiation therapy. Methods : Twenty patients with a hemangiopericytoma were treated between 1982 and 1999 in our department. They are composed of 13 patients of hemangiopericytoma and 7 patients who were initially diagnosed as angioblastic type meningioma and then confirmed as a hemangiopericytoma after review of their previous histopathology slides. The mean follow-up period was 99 months(1-256 months). The long-term outcomes after various treatment modalities were evaluated according to recurrence-free survival and image follow-up. Recurrence-free survival curves are compared between the patient groups according to the extent of removal and radiation therapy. Results : There were 10 cases of recurrence and 4 cases of distant metastases ; lung, liver and femur(2 cases) respectively. The 5-year recurrence rate was 37%, while the 10-year recurrence rose to 77%. There was also statistically significant difference of median recurrence-free survival between the completely-resected group(Simpson grade 1 or 2) and partially-resected group(Simpson grade 3 or 4 or 5) ; 137 months compared to 47 months, respectively(p=0.009). The median recurrence-free period after subtotal resection of tumor and postoperative radiotherapy was 47 months compared to 117 months of the patients who underwent gross total resection of tumor and did not receive radiotherapy. But radiation therapy alone did not show significant difference in recurrence-free survival. Marked tumor volume reduction and easy removal of tumors without bleeding were found in 2 recurred cases. Conclusion : The extent of tumor resection and presence of metastasis are the most important factors related to long-term outcome of the patients with hemangiopericytoma. Radiation therapy after the first operation did not have a role in extending the recurrence-free survival, but it affected favorably to decrease the size of residual mass and intraoperative bleeding during the second operation.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1049-1056
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• 2021

The purpose of this study was to develop a respiratory synchronization device for X-ray (X-RSD) to increase the reproducibility of inspiration when examining the Chest X-ray of a patient who difficulty in breathing coordination. The X-RSD was self-made using an air pressure sensor and air was injected by connecting a ventilator to the mannequin for CPR. At this time, the amount of injected air was quantified using the SkillReporting device. After placing the X-RSD on the chest of the mannequin, the amount of air was tested in 6 steps from 200 to 700 cc by 100 cc increased. For the accuracy evaluation, the sensitivity of X-RSD was measured by repeating a total of 80 measurements, and the sensitivity was 100%, and very precise results were obtained. After that, the images examined while viewing the X-RSD of the chest lateral examination and the images obtained by the blind examination were compared and evaluated. The lung volume of X-RSD was larger than that of the blind test, and the deviation was smaller. Overall, the use of X-RSD can help with chest X-ray examination of patients who have difficulty in cooperating, and it is thought that it will be possible to contribute to the reduction of exposure dose by reducing the repeat rate of general X-ray examinations.

• Radiation Oncology Journal
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• v.22 no.3
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• pp.225-233
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• 2004

Purpose: The Ideal breast irradiation method should provide an optimal dose distribution In the treated breast volume and a minimum scatter dose to the nearby normal tissue. Physical wedges have been used to Improve the dose distribution In the treated breast, but unfortunately Introduce an Increased scatter dose outside the treatment yield, pavllculariy to the contralateral breast. The typical physical wedge (FW) was compared with 4he virtual wedge (VW) to do)ermine the difference In the dose distribution affecting on the treated breast and the contralateral breast, lung, heart and surrounding perlpheral soft tissue. Methods and Materials: The data collected consisted of a measurement taken with solid water, a Humanoid Alderson Rando phantom and patients. The radiation doses at the ipsllateral breast and skin, contralateral breast and skin, surrounding peripheral soft tissue, and Ipsllateral lung and heart were compared using the physical wedge and virtual wedge and the radiation dose distribution and DVH of the treated breast were compared. The beam-on time of each treatment technique was also compared Furthermore, the doses at treated breast skin, contralateral breast skin and skin 1.5 cm away from 4he field margin were also measured using TLD in 7 patients of tangential breast Irradiation and compared the results with phantom measurements. Results: The virtual wedge showed a decreased peripheral dose than those of a typical physical wedge at 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, and 60$^{\circ}$. According to the TLD measurements with 15$^{\circ}$ and 30$^{\circ}$ virtual wedge, the Irradiation dose decreased by 1.35$\%$ and 2.55$\%$ In the contralateral breast and by 0.87$\%$ and 1.9$\%$ In the skin of the contralateral breast respectively. Furthermore, the Irradiation dose decreased by 2.7$\%$ and 6.0$\%$ in the Ipsllateral lung and by 0.96$\%$ and 2.5$\%$ in the heart. The VW fields had lower peripheral doses than those of the PW fields by 1.8$\%$ and 2.33$\%$. However the skin dose Increased by 2.4$\%$ and 4.58$\%$ In the Ipsliateral breast. VW fields, In general, use less monitor units than PW fields and shoriened beam-on time about half of PW. The DVH analysis showed that each delivery technique results In comparable dose distribution in treated breast. Conclusion: A modest dose reduction to the surrounding normal tissue and uniform target homogeneity were observed using the VW technique compare to the PW beam in tangential breast Irradiation The VW field is dosmetrically superlor to the PW beam and can be an efficient method for minimizing acute, late radiation morbidity and reduce 4he linear accelerator loading bV decreasing the radiation delivery time.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.140-152
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• 1998

Background: Prone position improves oxygenation in patients with ARDS probably by reducing shunt Reduction of shunt in prone position is thought to be effected by lowering of the critical opening pressure (COP) of the dorsal lung because the pleural pressure becomes less positive in prone position compared to supine position. It can then be assumed that prone position would bring about greater improvement in oxygenation when PEEP applied in supine position is just beneath COP than when PEEP is above COP. Hemodynamically, prone position is expected to attenuate the lifting of cardiac fossa induced by PEEP. Based on these backgrounds, we investigated whether the effect of prone position on oxygenation differs in magnitude according to the level of PEEP applied in supine position, and whether impaired cardiac output in supine position by PEEP can be restored in prone position. Methods: In seven mongrel dogs, $PaO_2/F_1O_2$(P/F) was measured in supine position and at prone position 30 min. Cardiac output (CO), stroke volume (SV), pulse rate (PR), and pulmonary artery occlusion pressure (PAOP) were measured in supine position, at prone position 5 min, and at prone position 30 min. After ARDS was established with warmed saline lavage(P/F ratio $134{\pm}72$ mm Hg), inflection point was measured by constant flow method($6.6{\pm}1.4cm$ $H_2O$), and the above variables were measured in supine and prone positions under the application of Low PEEP($5.0{\pm}1.2cm$ $H_2O$), and Optimal PEEP($9.0{\pm}1.2cm$ $H_2O$)(2 cm $H_2O$ below and above the inflection point, respectively) consecutively. Results : P/F ratio in supine position was $195{\pm}112$ mm Hg at Low PEEP and $466{\pm}63$ mm Hg at Optimal PEEP(p=0.003). Net increase of P/F ratio at prone position 30 min, however, was far greater at Low PEEP($205{\pm}90$ mm Hg) than at Optimal PEEP($33{\pm}33$ mm Hg)(p=0.009). Compared to CO in supine position at Optimal PEEP($2.4{\pm}0.5$ L/min), CO in prone improved to $3.4{\pm}0.6$ L/min at prone position 5 min (p=0.0180) and $3.6{\pm}0.7$ L/min at prone position 30 min (p=0.0180). Improvement in CO was attributable to the increase in SV: $14{\pm}2$ ml in supine position, $20{\pm}2$ ml at prone position 5 min (p=0.0180), and $21{\pm}2$ ml at prone position 30 min (p=0.0180), but not to change in PR or PAOP. When the dogs were turned to supine position again, MAP ($92{\pm}23$ mm Hg, p=0.009), CO ($2.4{\pm}0.5$ L/min, p=0.0277) and SV ($14{\pm}1$ ml, p=0.0277) were all decreased compared to prone position 30 min. Conclusion: Prone position in a dog with saline-lavaged acute lung injury appeared to augment the effect of relatively low PEEP on oxygenation, and also attenuate the adverse hemodynamic effect of relatively high PEEP. These findings suggest that a PEEP lower than Optimal PEEP can be adopted in prone position to achieve the goal of alveolar recruitment in ARDS avoiding the hemodynamic complications of a higher PEEP at the same time.