• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.20-24
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• 2009

Objective: In this study, the differences between two reconstruction methods were analyzed by comparing image uniformity and contrast according to Iteration and Subset, which were altered through the Iterative method and True X method, used in Siemens' PET/CT studies. Methods: The Phantom images were obtained by exposure for two minutes per one bed. To determine the image uniformity, the Coefficient of variance was used. Also, in order to compare the contrast value, we measured and analyzed the ratio of the SUV mean of Phantom image's hot spheres and the background. Results: Under the same reconstruction conditions (Iteration and Subset) of CV, the Iterative method was higher than the True X method. In the comparison of the SUV mean ratio of the background and hot sphere, the True X method had a closer rate than the Iterative method. Conclusion: The newly developed True X reconstruction method is better than the previously used Iterative method in terms of uniformity and contrast. However, the date for this study was only obtained using the Phantom device. In order to obtain more accurate and useful information from the experiment, further research should be conducted. Also, it is necessary to find the appropriate standards for Iteration and Subset for further experimentation.

• Radiation Oncology Journal
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• v.6 no.1
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• pp.63-73
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• 1988

One hundred fifty-four patients with the carcinoma of the uterine cervix were studied retrospectively to assess the result and impact of treatment at Department of Radiation Oncology, Korea University, Hae-Wha Hospital from Feb 1981 through Dec. 1986. Prior to radiotherapy, the patients were evaluated and staged by recommendation of FIGO including physical examination, pelvic examination, cystoscopy, rectosigmoidoscopy, chest X-ray, IVP. Ba enema. Also, an additional pelvic CT scan was obtained for some of the patients. The patients were treated by radiotherapy alone or adjuvant postoperative irradiation; in case of radiation therapy only, whole pelvic irradiation was given with Co-60 teletherapy unit via AP and PA parallel opposing fields or 4-oblique fields, 180 cGy per day, 5 days per week and intracavitary insertion was performed. In satges Ia, Ib, and IIa with small primary lesion, external irradiation was initially given to pelvis up to $2,000\~3,000\;cGy/2frac{1}{2}\;-3frac{1}{2}$ weeks and then intracavitary insertion was performed using Fletcher-Mini-Declos Applicator with cesium-137 cources and followed by external irradiation of $1,000\~2,000\;cGy/1frac{1}{2}\;-2frac{1}{2}$weeks via AP and PA parallel opposing fields with midline shield to spare of bladder and rectum. However, if the primary lesion is large, external irradiation was given without midline shield. More than stages IIb, the patients were treated by external beam irradiation up to 5,400cGy/30f for 6 weeks via 4-oblique portals and at the dose of 5,040cGy/28f the field was cut 5cm from the top margin for spare of small bowel, and followed by intracavitary irradiation, If there was residual tumor an additional dose of $900\~l,200cGy/5\~7f$ was given to parametrium and/or residual tumor area. Total dose of radiation to A and B-point were as follows; A-point; In early stages, Ia, Ib, IIa; $8,000\~9,000$ B-point $5,000\~6,000 cGy$ A-point; In advanced stages IIb, IIIa, IIIb; $9,000\~10,000$ B-point $60,000\~7,000cGy$ The results were obtained and as fellows; 1 The patients distribution according to FIGO staging system were stage Ia 6, Ib 27, IIa 28, IIb 54, IIIa 12, IIIb 18, and stage IVa 9. 2. Value of CT scan were demonstration of cervix tumor mass, parametrial and pelvic side wall tumor spread, pelvic and inguinal lymph nodes metastases, and hydronephrosis. Three dimensional quantitative demonstration of tumor volume is also important in planning radiation therapy. Another advantage of CT scan was detection of recurrent tumor after radiation or surgery. 3. Local control rate of tumor according to the size was $91.3\%$ for less than 5cm in size and $44.6\%$ in tumor over 5cm (p<0.0068). 4. Thirty out of 50 recurrent sites has locoregional failures and 17 cases has distant metastases. And the para-aortic lymph nodes were the most common site for distant metastases. 5. The most common complication was temporal rectal bleeding which was controlled most by conservative management. However, 4 patients required for endoscopic cauterization. 6. The 5-year survival rates showed; stage la and Ib $95\%,\;stage\;IIa\;81\%\;stage\;lIb\;67\%,\;stage\;IIIa\;37.7\%,\;stage\;IIIb\;23\%$ and 3-year survival rate of stage IVa showed $11.6%$, retrospectively.

• Radiation Oncology Journal
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• v.28 no.3
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• pp.166-176
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• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.768-776
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• 2010

This study was conducted to predict number and fresh weight of leaves, and total leaf area of a single-stemmed rose 'Vital' based on the accumulated thermal units, and to develop a model of shoot development for the prediction of the time when the flowering shoot reaches a phenological stage in a plant factory system. The base temperature ($T_b$), optimum temperature ($T_{opt}$), and maximum temperature ($T_{max}$) were estimated by regressing the rate of shoot development against the temperature gradient. The rate of shoot development ($R$, $d^{-1}$) for the phase from cutting to bud break (CT-BB) was best described by a linear model $R_b$ ($d^{-1}$) = -0.0089 + $0.0016{\cdot}temp$. The rate of shoot development for the phase from bud break to harvest (BB-HV) was fitted to the parabolic model $R_h$ ($d^{-1}$) = $-0.0001{\cdot}temp^2$ + $0.0054{\cdot}temp$ - 0.0484. The $T_b$, $T_{opt}$, and $T_{max}$ values were 5.56, 27.0, and $42.7^{\circ}C$, respectively. The $T_b$ value was used in the thermal unit computations for the shoot development. Number of leaves, leaf area (LA), and leaf fresh weight showed sigmoidal curves regardless of the cut time. The shoot development and leaf area model was described as a sigmoidal function using thermal units. Leaf area was described as LA = 578.7 $[1+(thermal units/956.1)^{-8.54}]^{-1}$. Estimated and observed shoot length and leaf fresh weight showed a reasonably good fit with 1.060 ($R^2=0.976^{***}$) and 1.043 ($R^2=0.955^{***}$), respectively. The average thermal units required from cutting to transplant and from transplant to harvest stages were $426{\pm}42^{\circ}C{\cdot}d$ and $783{\pm}24^{\circ}C{\cdot}d$, respectively.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.2
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• pp.29-37
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• 2019

Purpose DMIDR(Discovery Molecular Imaging Digital Ready, General Electric Healthcare, USA) is a PET/CT scanner designed to allow application of PSF(Point Spread Function), TOF(Time of Flight) and Q.Clear algorithm. Especially, Q.Clear is a reconstruction algorithm which can overcome the limitation of OSEM(Ordered Subset Expectation Maximization) and reduce the image noise based on voxel unit. The aim of this paper is to evaluate the performance of reconstruction algorithms and optimize the algorithm combination to improve the accurate SUV(Standardized Uptake Value) measurement and lesion detectability. Materials and Methods PET phantom was filled with $^{18}F-FDG$ radioactivity concentration ratio of hot to background was in a ratio of 2:1, 4:1 and 8:1. Scan was performed using the NEMA protocols. Scan data was reconstructed using combination of (1)VPFX(VUE point FX(TOF)), (2)VPHD-S(VUE Point HD+PSF), (3)VPFX-S (TOF+PSF), (4)QCHD-S-400((VUE Point HD+Q.Clear(${\beta}-strength$ 400)+PSF), (5)QCFX-S-400(TOF +Q.Clear(${\beta}-strength$ 400)+PSF), (6)QCHD-S-50(VUE Point HD+Q.Clear(${\beta}-strength$ 50)+PSF) and (7)QCFX-S-50(TOF+Q.Clear(${\beta}-strength$ 50)+PSF). CR(Contrast Recovery) and BV(Background Variability) were compared. Also, SNR(Signal to Noise Ratio) and RC(Recovery Coefficient) of counts and SUV were compared respectively. Results VPFX-S showed the highest CR value in sphere size of 10 and 13 mm, and QCFX-S-50 showed the highest value in spheres greater than 17 mm. In comparison of BV and SNR, QCFX-S-400 and QCHD-S-400 showed good results. The results of SUV measurement were proportional to the H/B ratio. RC for SUV is in inverse proportion to the H/B ratio and QCFX-S-50 showed highest value. In addition, reconstruction algorithm of Q.Clear using 400 of ${\beta}-strength$ showed lower value. Conclusion When higher ${\beta}-strength$ was applied Q.Clear showed better image quality by reducing the noise. On the contrary, lower ${\beta}-strength$ was applied Q.Clear showed that sharpness increase and PVE(Partial Volume Effect) decrease, so it is possible to measure SUV based on high RC comparing to conventional reconstruction conditions. An appropriate choice of these reconstruction algorithm can improve the accuracy and lesion detectability. In this reason, it is necessary to optimize the algorithm parameter according to the purpose.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.1
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• pp.115-121
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• 2010

Purpose: The purpose of this study is to measure F-18 FDG with two different types of dose calibrator measuring radionuclide and radioactivity and investigate the effect of F-18 FDG on SUV (Standard Uptake Value) in human body. Materials and Methods: Two different dose calibrators used in this study are CRC-15 Dual PET (Capintec) and CRC-15R (Capintec). Inject 1 mL, 2 mL, 3 mL of F-18 FDG into three 2 mL syringes, respectively, and measure initial radioactivity from each dose calibrator. Then measure and record radioactivity at 30 minute interval for 270 minutes. According to the initial radioactivity, linearity between decay factor driven from radioactive decay formula and the values measured by dose calibrator have been analyzed by simple linear regression. Fine linear regression line optimizing values measured with CRC-15 through regression analysis on the basis of the volume of which the measured value is close to the most ideal one in CRC-15 Dual PET. Create ROI on lung, liver, and region part of 50 persons who has taken PET/CT test, applying values from linear regression equation, and find SUV. We have also performed paired t-test to examine statistically significant difference in the radioactivity measured with CRC-15 Dual PET, CRC-15R and its SUV. Results: Regression analysis of radioactivity measured with CRC-15 Dual PET and CRC-15R shows results as follows: in the case 1 mL, the r statistic representing correlation was 0.9999 and linear regression equation was y=1.0345x+0.2601; in 2 mL case, r=0.9999, linear regression equation y=1.0226x+0.1669; in 3 mL case, r=0.9999, linear regression equation y=1.0094x+0.1577. Based on the linear regression equation from each volume, t-test results show significant difference in SUV of ROI in lung, liver, region part in all three case. P-values in each case are as follows: in 1 mL case, lung, liver and region (p<0.0001); in 2 mL case, lung (p<0.002), liver and region (p<0.0001); in 3 mL case, lung (p<0.044), liver and region (p<0.0001). Conclusion: Radioactivity measured with CRC-15 Dual PET, CRC-15R, dose calibrator for F-18 FDG test, do not show difference correlation, while these values infer that SUV has significant differences in the aspect of uptake in human body. Therefore, it is necessary to consider the difference of SUV in human body when using these dose calibrator.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2443-2446
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• 2013

Published data have shown that the levels of vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (sVEGFR-1) in plasma and pleural effusion might be usefulness for lung cancer diagnosis. Here, we performed a prospective study to investigate the utility of VEGF and sVEGFR-1 in bronchoalveolar lavage fluid (BALF) for differential diagnosis of primary lung cancer. A total of 56 patients with solitary pulmonary massed by chest radiograph or CT screening were enrolled in this study. BALF and plasma samples were obtained from all patients and analyzed for VEGF and sVEGFR-1 using a commercially available sandwich ELISA kit. The results showed that the levels of VEGF in BALF were significantly higher in patients with a malignant pulmonary mass compared with patients with a benign mass (P < 0.001). However, no significant difference of sVEGFR-1 in BALF was found between malignant and non-malignant groups (P = 0.43). With a cut-off value of 214 pg/ml, VEGF showed a sensitivity and specificity of 81.8% and 84.2%, respectively, in predicting the malignant nature of a solitary pulmonary mass. Our study suggests that VEGF is significantly increased in BALF among patients with lung cancer than in benign diseases. Measurement of VEGF in BALF might be helpful for differential diagnosis of primary lung cancer.

• Journal of Korean Neurosurgical Society
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• v.59 no.2
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• pp.129-136
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• 2016

Objective : The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). Methods : A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. Results : Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. Conclusion : The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.651-656
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• 1996

We have experienced a case of sarcoidosis appearing asymmetrical diffuse interstitial lung lesions with multiple lymphadenopathy. This patient was a 57 year-old female who had been in good health until 2 months ago. At that time she noted the onset of an exertional dyspnea and weakness. Pulmonary function tests showed moderate obstructive pattern with mild decreased DLco. In the chest CT, multiple lymphadenopathy with small nodular lesions are scattered, and the impression was a metastatic lymph nodes with lymphangitic carcinomatosis. In bronchofiberscopy, we noted luminal narrowing by extrinsic compression in the right middle and lower lobe bronchi. And microscopic examination of by bronchofiberscopic biopsy showed chronic inflammation. Thus we performed subcarinal and tight supraclaviclar lymph nodes aspiration biopsy cytology, and that revealed class 0 and class 1, respectively. Finally, we performed an excisional biopsy for the right scalene lymph node, which revealed the specimen as a noncaseating granuloma. The angiotensin convecting enzyme level was overt two folds compared to normal value. And the patient had negative PPD skin test and hyperglobulinemia. After 18 weeks treatment with prednisone, the signs and symptoms which the patient clad suffered from, disappeared.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.67-72
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• 2010

The fracture toughness for the LBB analysis of piping is generally determined by the J-integral according to ASTM E1820. However, since this evaluates a base metal, the fracture toughness for narrow gap welding can be differently than the real value. This study evaluated the plastic  factor of the narrow gap welding part of a nuclear piping with SA508 Cl.1a and SA312 TP316. Also, it performed the fracture toughness test for the narrow gap welding part and applied the new plastic $\eta$ factor equation by Huh, et al. and then compared the results with those according with the ASTM standard.