• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.151-158
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• 2004

Background : When a non small cell lung caner patient at the $_cT_{1-2}N_0M_0$ stage is diagnosed with intrapulmonary nodule(s), the treatment plan and prognosis of the patient largely depend on whether the nodule is benign or malignant. In most cases, however, it is hard to conduct a biopsy on such a nodule, due to its small size. Furthermore, the predictive factors that may imply benignancy or malignancy of the nodules remain unknown. As such, the purpose of our study was to validate the incidence of malignant nodules in such cases, and find if there are any predictive factors. Methods : Chest computed tomography(CT) scans and the medical records of 444 patients, who had undergone non small cell lung cancer surgery, between July, 2001 and September, 2003, at Seoul National University Hospital, were retrospectively reviewed. Among $_cT_{1-2}N_0M_0$ non small cell lung cancer patients, with intrapulmonary nodule(s), only those cases where a CT scan or a biopsy of the nodules had been conducted, and had been followed up at intervals of more than 6 months were included. However, patients who had received chemotherapy or radiation therapy, pre- or post-operatively, or with calcified nodules, were excluded. Results : Our study group consisted of 39 patients, divided into two groups. The first group, 33 patients, had benign nodules, and the second group, 6 patients, had malignant nodules. The two groups were compared with regard to gender, age, cell type, pathologic stage, shape, size, location and number of nodules and presence of calcification around the nodules. There was no statistically significant difference between the two groups. Conclusion : The intrapulmonary nodules in non small cell lung cancer patients at the $_cT_{1-2}N_0M_0$ stage were mostly benign. Therefore, surgical treatment for such patients can be considered. Moreover, without predictive factors, pathological confirmation of the diagnosed nodules should be sought in all patients.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.479-485
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• 2007

Background: The purpose of this study was to evaluate the differences in CT findings according to sputum smear-positive or -negative results in patients with active pulmonary tuberculosis having a single cavity. Methods: A total of 32 patients with active pulmonary tuberculosis having a single cavity on CT were classified into two groups: smear-positive (n=19) and smear-negative (n=13). The CT findings were reviewed retrospectively. The presence of consolidation, the number of lobes showing consolidation, ground-glass opacity, micronodules and nodule, the maximum diameter of the cavity, and the shape and maximum thickness of the cavity wall were assessed. Result: The maximum diameter of the cavity was $33.84{\pm}13.65mm$ and $27.08{\pm}9.04mm $ in the smear-positive and -negative groups, respectively (p>0.05). The amount of consolidation and the number of lobes with consolidation were found to be 89.5% and 30.8% (p=0.01) and $1.37{\pm}0.90$ and $0.31{\pm}0.48$ (p=0.0002) in the smear-positive and -negative groups, respectively. Consolidations in two or more lobes were only noted in 31.6% of in the sputum smear- positive group (p< 0.05). There were no other significant differences between the two groups. The sensitivity, specificity, positive and negative predictive values for the presence of consolidation were 89.5%, 69.2%, 73.9%, and 81.8%, respectively. Conclusion: While the absence of consolidation on CT may be associated with sputum smear-negative results in patients with active pulmonary tuberculosis having a single cavity, the presence of consolidation in two or more lobes on CT may be associated with spear-positive results in these patients.

• Tuberculosis and Respiratory Diseases
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• v.65 no.5
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• pp.390-395
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• 2008

Background: Since the early 1980s, interferon-alpha ($IFN-{\alpha}$) has been used as adjuvant therapy in pediatric patients with recurrent respiratory papillomatosis (RRP). However, its efficacy in adults needs to be validated. Since 2002, Samsung Medical Center's guidelines have mandated regular injection of $IFN-{\alpha}$ in patients with RRP to prevent recurrence. To evaluate these guidelines, patient data were investigated. Methods: Five patients diagnosed as having RRP by bronchoscopy and histopathology were included. After initial bronchoscopic intervention, including laser cauterization, all patients received subcutaneous injection of 6 million units of $IFN-{\alpha}$ every 2 months. Further bronchoscopic intervention was carried out as needed. Patients were regularly evaluated using bronchoscopy or computed tomography. Results: The median age of the patients was 44 years (range 13~68), and the median duration of papillomatosis was 31 years (range 1~45). Three and two patients had juvenile-onset and adult-onset disease, respectively. Two patients had a history of tracheostomy at the time of diagnosis. The median duration of $IFN-{\alpha}$ therapy was 56 months (range 12~66). Two patients showed complete remission at 12 and 36 months after $IFN-{\alpha}$ injection, respectively. The other three patients showed partial remission, and the number of laser therapy sessions was significantly reduced.Conclusion: Intermittent $IFN-{\alpha}$ injection is effective in patients with long-standing RRP and can reduce the number of laser therapy sessions required in their treatment.

• Korea Journal of Hospital Management
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• v.2 no.1
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• pp.1-21
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• 1997

In order to analyze the shifts in the volume and profits of Computed Tomography(CT) and Magnetic Resonance Imaging(MRI) utilization for a year before and after the implementation of insurance coverage for CT, this study has been undertaken examining CT and MRI cost data from 'Y' University Hospital situated in Seoul, Korea. Following are the results of this study: 1. The medical insurance payment for CT, implemented on January 1, 1996, increased CT utilization from January 1996 to April 1996 due to low insurance premiums: however, from May 1996 the number of CT cases significantly decreased as a result of strengthened medical cost reviews and the new 'Detailed standards for approval of CT' announced near the end of April 1996 by the insurer. 2. Since the implementation of insurance coverage for CT, CT fee reduction rates for reimbursements by the insurer to the hospital were 50% and 40% for January and February, respectively, and 31% and 15% for March and April. A significant point in the lowering of the reduction rate was reached in May at 11%; furthermore, since June the reduction rate fell below the average reduction rate for reimbursements for all procedures. If the 'Detailed standards for approval of CT' had been announced before the implementation of insurance coverage for CT, CT utilization would not have been so high due to the need to meet those 'standards'. In addition, loss of hospital profits resulting from the reduction for reimbursements would not have occurred. 3. The shifts in MRI utilization showed that there was no particular change with the beginning of insurance coverage for CT, and the introduction of the 'Detailed standards for approval of CT' made MRI utilization increase because MRI is free of restrictions imposed by the insurer. 4. The relationship between CT utilization and MRI utilization showed that they were supplementary to each other before insurance coverage for CT, but that CT was substituted for MRI because of strengthened medical cost reviews after t~e beginning of insurance coverage for CT. 5. The shifts in volume by patient characteristics showed that the number of inappropriate case patients, according to the insurer's "Standards for approval", decreased more than the number of appropriate case patients after the introduction of insurance coverage for CT. Therefore, the health insurance fee schemes for CT have influenced patient care. 6. The shifts in profits from CT utilization showed a net profit decrease of 31.6%. In order to match the pre-coverage profit level, 5,471 more cases would need to be seen and productivity would need to be increased by 32.7%. This profit decrease resulted from a decrease of CT utilization and low reimbursements. With insurance coverage, net profits from CT were 24.4%, and a margin of safety ratio was 39.6%. Because of the net profits and margin of safety ratio, CT utilization fees for insured appropriate cases could not be considered inappropriate. 7. The shifts in profits from MRI utilization before and after the introduction of CT coverage showed that in order to match pre-CT coverage profit levels, 2,011 more cases would need to be seen and productivity would need to be increased by 9.2%. The reasons for needing to increase the number of cases and productivity result from cost burdens created by adding new MRI units. But with CT coverage already begun, MRI utilization increased. Combined with a minor increase in the MRI fee schedule, MRI utilization showed a net profit increase of 18.5%. Net profits of 62.8% and a 'margin of safety ratio' of 43.1% for MRI utilization showed that the hospital relied on this non-covered procedure for profits. 8. The shifts in profits from CT and MRI utilization showed the net profits from CT decreased by 2.33billion Won while the net profits from MRI increased by 815.7million Won. Overall, these two together showed a net profit decrease of 1.51billion Won. The shifts in utilization showed a functional substitutionary relationship, but the shifts in profits did not show a substitutionary relationship. From these results, We can conclude that if insurance is to be expanded to include previously uncovered procedures using expensive medical equipment, detailed standards should be prepared in advance. The decrease in profits from the shifts in coverage and changes in fees is a difficult burden that should be shared, not carried by the hospital alone. Also, a new or improved fee schedule system should include revised standards between items listed and the appropriateness of the fee schedule should constantly be ensured. This study focused on one university hospital in Seoul and is therefore limited in general applicability. But it is valuable for considering current issues and problems, such as the influence of CT coverage on hospital management. Future studies will hopefully expand the scope of the issues considered here.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.123-133
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• 2007

Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of multi-detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, $70{\sim}450\;mA$). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, 2-axis modulation resulted in reduction of CTDIvol (range, $-6.5%{\sim}-35.6%$) and DLP (range, $-0.2%{\sim}-20.2%$). Compared with manually selected fixed tube current, 2-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5259-5264
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• 2014

Background: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Materials and Methods: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose ($D_{Max}$) to rectum was the highest recorded dose at one of these five points. Using the HDRplus 2.6 brachyhtherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded ($D_{2cc}$) for all individual fractions. The mean $D_{2cc}$ of rectum was compared to the means of ICRU rectal point and rectal $D_{Max}$ using the Student's t-test. The mean $D_{2cc}$ of bladder was compared with the mean ICRU bladder point using the same statistical test. The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (${\alpha}/{\beta}$ value of 10 Gy for target, 3 Gy for organs at risk). Results: The total prescribed dose was $77.5Gy{\alpha}/{\beta}10$. The mean dose to the rectum was $4.58{\pm}1.22Gy$ for $D_{2cc}$, $3.76{\pm}0.65Gy$ at $D_{ICRU}$ and $4.75{\pm}1.01Gy$ at $D_{Max}$. The mean rectal $D_{2cc}$ dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48-1.19Gy). The mean EQD2 was $68.52{\pm}7.24Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$, $61.71{\pm}2.77Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$ and $69.24{\pm}6.02Gy_{{\alpha}/{\beta}3}$ at $D_{Max}$. The mean ratio of $D_{2cc}$ rectum to $D_{ICRU}$ rectum was 1.25 and the mean ratio of $D_{2cc}$ rectum to $D_{Max}$ rectum was 0.98 for all individual fractions. The mean dose to the bladder was $6.00{\pm}1.90Gy$ for $D_{2cc}$ and $5.10{\pm}2.03Gy$ at $D_{ICRU}$. However, the mean $D_{2cc}$ dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25Gy). The mean EQD2 was $81.85{\pm}13.03Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$ and $74.11{\pm}19.39Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$. The mean ratio of $D_{2cc}$ bladder to $D_{ICRU}$ bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose. Conclusions: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the $D_{2cc}$ and rectal $D_{Max}$ for $D_{2cc}$. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the $D_{2cc}$.

• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.160-166
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• 2012

Purpose: The aim of this study was to determine the patterns of the stress distribution within the reconstructed anterior cruciate ligament (ACL) double bundles in response to an anterior tibial load and rotatory load at $45^{\circ}$ flexed knee model by use of a 3-dimensional finite element analysis (FEM). Materials and Methods: The $0^{\circ}$ and $45^{\circ}$ flexed 3-D knee model were reconstructed based on the high resolution computed tomography (CT) images from the right knee of a healthy male subject. To simulate double bundle ACL reconstruction, in $0^{\circ}$ analytic model, four 7 mm diameter tunnels were created at the center of each anteromedial (AM) and posterolateral (PL) footprints on the femur and tibia. The grafts were inserted into the corresponding bone tunnels and then reconstructed knee model was flexed to $45^{\circ}$. As a next step, the 5 mm anterior tibial load and internal rotational load of $10^{\circ}$ were applied on the final Computer aided design (CAD) model. And then stress patterns of each bundle were assessed using a finite element analysis. Results: In response to the 5 mm of anterior tibial load, the AM bundle showed increased stresses around the tibial and femoral attachment sites; especially in the anterior aspect of the bundle. In the PL bundle, the highest stress concentration was also noticed on the anterior aspect of the bundle. Under $10^{\circ}$ internal rotational load, the stress concentration was predominant around the anterior aspect of the tibial attachment site within the AM bundle. The PL bundle also showed highest stress concentration on the anterior aspect of the bundle. Conclusion: Although the stress patterns were not identical among the AM and PL bundle, there were common trends in the stress distribution. The stress concentration was predominant on the anterior aspect of both bundles in response to the anterior tibial load and rotatory load.

• Progress in Medical Physics
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• v.26 no.1
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• pp.6-11
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• 2015

The purpose of this study was to analyze the rotational errors of roll, pitch, and yaw in the whole breast cancer treated by the three-dimensional radiation therapy (3D-CRT) using TomoDirect (TD). Twenty-patient previously treated with TD 3D-CRT was selected. We performed a retrospective clinical analysis based on 80 images of megavoltage computed tomography (MVCT) including the systematic and random variation with patient setup errors and treatment setup margin (mm). In addition, a rotational error (degree) for each patient was analyzed using the automatic image registration. The treatment margin of X, Y, and Z directions were 4.2 mm, 6.2 mm, and 6.4 mm, respectively. The mean value of the rotational error for roll, pitch, and yaw were $0.3^{\circ}$, $0.5^{\circ}$, $0.1^{\circ}$, and all of systematic and random error was within $1.0^{\circ}$. The errors of patient positioning with the Y and Z directions have generally been mainly higher than the X direction. The percentage in treatment fractions in less than $2^{\circ}$ at roll, pitch, and yaw are 95.1%, 98.8%, and 97.5%, respectively. However, the edge of upper and lower (i.e., bottom) based on the center of therapy region (point) will quite a possibility that it is expected to twist even longer as the length of treatment region. The patient-specific characters should be considered for the accuracy and reproducibility of treatment and it is necessary to confirm periodically the rotational errors, including patient repositioning and repeating MVCT scan.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.232-243
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• 2014

Purpose : To evaluate the incidence of secondary contiguous or non-contiguous subchondral bone impactions (SBI) in subaxial cervical spinal injury and associated primary injury patterns. Materials and Methods: A retrospective review of computed tomography, magnetic resonance imaging, and medical records was carried out for 47 patients who had sustained a subaxial cervical spinal injury. Presence, number, level, and sites of secondary contiguous or non-contiguous SBI were recorded. To evaluate primary injury patterns, the level and number of primary injury sites of subaxial cervical spine injury, injury morphology, anterior/posterior discoligamentous complex (ADC/PDC) injury, posterior ligamentous complex (PLC) injury, spinal cord injury, and mechanism of injury (MOI) were analyzed. Differences in primary injury pattern of subaxial cervical spine injury and MOI between patients with and without SBI, and between contiguous or non-contiguous SBI were analyzed using the Mann-Whitney U test, Pearson's chi square test and Fisher's exact test. Results: Eighteen patients (18/47, 38.29%) had developed contiguous (n=9) or non-contiguous (n=9) SBI, most commonly involving T3 (15/47, 31.91%) and 3 levels (6/18, 33.33%). All SBIs had developed near the anterosuperior region of the body and the superior endplate and were the result of a high-impact MOI. SBIs were statistically significant in association with injury morphology and PLC injury (P=0.001, P=0.009, respectively) at the primary injury site. Non-contiguous SBI was more frequently accompanied by upper cervical spinal injuries in association with PDC injuries, as opposed to contiguous SBI, with statistical significance (P=0.009), while no other statistically significant differences were found. Conclusion: Secondary SBIs are common and probably associated with subaxial cervical spinal injuries with high energy compressive flexion forces.

• Journal of Nutrition and Health
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• v.43 no.4
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• pp.374-381
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• 2010

This study was performed to examine the diet effect of green coffee bean extract on body fat reduction. Overweight/obese women (body mass index > $23\;kg/m^2$ or body fat > 27%) who were not diagnosed any type of disease were included in this study and subjects were randomly assigned to green coffee bean extract group (n = 23) or placebo group (n = 20). We measured anthropometric parameters, abdominal fat distribution by computed tomography and blood components before and after the 8-weeks intervention period. After supplementation, green coffee bean extract group showed a significant reduction of body weight (p < 0.01), body fat percent (p < 0.01), total fat area at L1 vertebra (-4.8%, p < 0.05) and visceral fat area at L4 vertebra was(-4.7%, p < 0.05). In addition, total fat area and visceral fat area at L1 vertebra decreased significantly in green coffee bean extract group compared with placebo group (p < 0.05, p < 0.05 respectively). The result of present study demonstrated that the supplementation of green coffee bean extract for 8 weeks can give beneficial effects on body fat reduction and visceral fat accumulation.