• The Korean Journal of Nuclear Medicine
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• v.13 no.1_2
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• pp.45-53
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• 1979

Bone scans with $^{99m}Tc$-MDP (methylene diphosphonate) was analysed in 112 patients with various type of biopsy proven malignant tumor who visited Seoul National University Hospital from March 1979 to August 1979. The results were as follows; 1. Of the 112 cases, bone scans were positive in 61 cases (54.1%), while only 27 cases (24.1%) were positive in roentgenogram. 2. Of the 61 cases with positive bone scan, bone metastases were found in 25 cases by roentgenogram. Of the 51 cases with negative bone scan, bone metastasis was found in only 1 case by roentgenogram. 3. In comparison of bone scan and roentgenogram by number of regions, 137 regions were positive in bone scan or roentgenogram. Of these, 46 regions (33.5%) were both bone scan and roentgenogram positive, 89 regions (65.0%) were bone scan positive roentgenogram negative, and 2 regions were bone scan negative roentgenogram positive. 4. Bone scan and roentgenographic findings had significant correlation with the presence of bone pain but no significant correlation with the elevated level of serum alkaline phosphatase, acid phosphatase, Ca, and P. From above result, we found that bone scan was more sensitive than roentgenogram in early detection of bone metastasis in malignant tumors.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.1-10
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• 2004

Statement of problem : Tooth wear is physiological phenomenon. Ninety-seven percent of normal people have tooth wear and about 7% has pathologic teeth wear. If we know the amount of tooth surface loss caused by pathologic tooth wear, we may restore it ideally Purpose : Recently measurement of tooth wear by using 3D scan has been increasing. Therefore, we need to know how accurate 3D scan is. Past accuracy test on 3D scan was about linear change, but as we know that tooth wear is volume change. Thus, the purpose of this study is to know how accurate 3D scan is. Material and Methods : For accuracy test of 3D scanner volume values measured by 3D scanner and micro-balance were compared. For test I, preliminary, 3 ball samples and 3 circular cones were made with pattern resin. For test II, 10 teeth shape rubber samples were used. Results and Conclusion : 1. The result of the accuracy test on 3D scan with 3 ball samples and 3 circular cones made of pattern resin has no significant difference(p<0.05). 2. The result of the accuracy test on 3D scan with 10 samples of tooth shape rubber has no significant difference (p<0.05). As a result, we may concluded the analysis of quantifying tooth wear used by 3D scan is useful in the clinic.

• Progress in Medical Physics
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• v.13 no.3
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• pp.139-148
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• 2002

The measured attenuation correction with transmission (Tx) scans produced quantitatively accurate images. However, it was not clear for optimal emission (Ex) and Tx scan time in PET imaging. This study was to evaluate acceptable Ex and Tx scan time by simulating clinical situations using various phantoms. Cylindrical and NEMA phantom were used for $^{18}$ F-PET scan using 2D protocol in GE Advance PETTM scanner. Cylindrical phantom was filled with 136 MBq 18F, and five regions of interests (ROI) were drawn on 23 slices. NEMA phantom had three inserts containing water, air and polytetrafluoro-ethylene (PTFE). Outside of these inserts were filled with 309 MBq of $^{18}$ F, and total 12 ROIs were drawn on 23 slices. Scans were carried out according to five Ex scan times: 2, 5, 10, 15, and 30 min, and nine Tx scan times: 2, 3, 4, 5, 7, 10, 15, 20, and 30 min. Images were reconstructed using measured attenuation correction, and ROI analyses were performed for all images, and mean, standard deviation (SD), coefficient of variation and percent errors were calculated. For cylindrical phantom study, ROI mean and SD were decreased as Ex and Tx time increased. Coefficients of variation were kept constant, when Tx was greater than 10 min. The amount of error decreased for the increment of Ex time from 10 min to 15 min was almost the same to that from 15 min to 30 min. In NEMA phantom Tx 15 min showed the lowest er개r level when the percent errors for three inserts were summed for all of the Ex times. This study suggested that Ex 15 min and Tx 15 min were acceptable as optimal scan time for the scanning protocol and the dose of radiopharmaceuticals used in these phantom study.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.212-217
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• 2015

Purpose: For a single time-point hyperpolarized $^{13}C$ magnetic resonance spectroscopy imaging (MRSI) of animal models, scan-time window after injecting substrates is critical in terms of signal-to-noise ratio (SNR) of downstream metabolites. Pre-scans of time-resolved magnetic resonance spectroscopy (MRS) can be performed to determine the scan-time window. In this study, based on two-site exchange model, protocol-specific simulation approaches were developed for $^{13}C$ MRSI and the optimal scan-time window was determined to maximize the SNR of downstream metabolites. Materials and Methods: The arterial input function and conversion rate constant from injected substrates (pyruvate) to downstream metabolite (lactate) were precalibrated, based on pre-scans of time-resolved MRS. MRSI was simulated using two-site exchange model with considerations of scan parameters of MRSI. Optimal scan-time window for mapping lactate was chosen from simulated lactate intensity maps. The performance was validated by multiple in vivo experiments of BALB/C nude mice with MDA-MB-231 breast tumor cells. As a comparison, MRSI were performed with other scan-time windows simply chosen from the lactate signal intensities of pre-scan time-resolved MRS. Results: The optimal scan timing for our animal models was determined by simulation, and was found to be 15 s after injection of the pyruvate. Compared to the simple approach, we observed that the lactate peak signal to noise ratio (PSNR) was increased by 230%. Conclusion: Optimal scan timing to measure downstream metabolites using hyperpolarized $^{13}C$ MRSI can be determined by the proposed protocol-specific simulation approaches.

• Journal of Oral Medicine and Pain
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• v.25 no.2
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• pp.145-151
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• 2000

The present study was performed to investigate the relationship between the salivary flow rate and the interpretation results of salivary scan in the patients with dry mouth. Twenty-five patients with dry mouth who visited the Dept. of Oral Medicine & Oral Diagnosis, Seoul National University Dental Hospital, were included. The unstimulated whole salivary flow rate was determined by the spitting method and the stimulated whole salivary flow rate was measured with gum-base chewing. Salivary scan was performed after the infusion of $^{99m}technetium$ pertechnetate(Tc) and interpreted. The obtained results were as follows: 1. The unstimulated and stimulated whole salivary flow rate were significantly decreased compared to normal value, which reflected the extensive destruction of salivary gland function in the patients with dry mouth. 2. The unstimulated and stimulated whole salivary flow rate were decreased in the group with decreased function in salivary scan compared with the group with normal function in salivary scan. However, there was no statistical significance between groups. 3. The difference between the stimulated and unstimulated whole salivary flow rates was greater in the group with normal function in salivary scan compared with the group with decreased function in salivary scan. 4. There was significant positive correlation between the stimulated and unstimulated whole salivary flow rates. The level of correlation was higher in the group with decreased function in salivary scan than the group with normal function in salivary scan. Collectively, these data suggested that salivary scan had the limited value. The comprehensive evaluation including history taking, clinical examination, clinical laboratory as well as the measurement of salivary flow rate are need for patients with dry mouth.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.305-311
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• 2019

In this study, present the most useful delay scan time by statistical analysis of SUVm data for 30 suspected pancreatic cancer patients. Two statistical analysis and a mathematical model was applied to the theoretical formula by glucose and insulin mechanics, and a mathematical model was created. Statistical analysis was performed via Metlab p/g. Optimal delay scan time was suggested by Metlab p/g for the change of SUV value over time.In this study, for diagnosis pancreatic cancer by dual time point PET/CT, propose optimal delay scan time 131.5 minuts. The proposed delay scan time showed statistical reliability applicable to the diagnosis of pancreatic cancer (p<0.05). Delayed scanning with the suggested delay scan time of 131.5 minutes is considered to be useful for the diagnosis of pancreatic cancer compared to general PET / CT scan.hen the delayed test is performed with the proposed delay scan time 131.5 minuts, Compared with general PET/CT scans.

• Journal of the Korean Society of Radiology
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• v.6 no.4
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• pp.281-290
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• 2012

The difference of radiation dose of MDCT due to different protocols between hospitals was analyzed by CTDI, DLP, the number of Slice and the number of DLP/Slice in 30 cases of the head, the abdomen and the chest that have 10 cases each from MDCT examination of the department of diagnostic imaging of three general hospitals in Gyeongsangbuk-do. The difference of image quality, CTDI, DLP, radiation dose in the eye and radiation dose in thyroid was analyzed after both helical scan and normal scan for head CT were performed because a protocol of head CT is relatively simple and head CT is the most frequent case. Head CT was significantly higher in two-thirds of hospitals compared to A hospital that does not exceed a CTDI diagnostic reference level (IAEA 50mGy, Korea 60mGy) (p<0.001). DLP was higher in one-third of hospitals than a diagnostic reference level of IAEA 1,050mGy.cm and Korea 1,000mGy.cm and two-thirds exceeded the recommendation of Korea and those were significantly higher than A hospital that does not exceed a diagnostic reference level (p<0.001). Abdomen CT showed 119mGy that was higher than a diagnostic reference level of IAEA 25mGy and Korea 20mGy in one-third. DLP in all hospitals was higher that Korea recommendation of 700mGy.cm. Among target hospitals, C hospital showed high radiation dose in all tests because MPR and 3D were of great importance due to low pitch and high Tube Curren. To analyze the difference of radiation dose by scan methods, normal scan and helical scan for head CT of the same patient were performed. In the result, CTDI and DLP of helical CT were higher 63.4% and 93.7% than normal scan (p<0.05, p<0.01). However, normal scan of radiation dose in thyroid was higher 87.26% (p<0.01). Beam of helical CT looked like a bell in the deep part and the marginal part so thyroid was exposed with low radiation dose deviated from central beam. In addition, helical scan used Gantry angle perpendicularly and normal scan used it parallel to the orbitomeatal line. Therefore, radiation dose in thyroid decreased in helical scan. However, a protocol in this study showed higher radiation dose than diagnostic reference level of KFDA. To obey the recommendation of KFDA, low Tube Curren and high pitch were demanded. In this study, the difference of image quality between normal scan and helical scan was not significant. Therefore, a standardized protocol of normal scan was generally used and protective gear for thyroid was needed except a special case. We studied a part of CT cases in the local area. Therefore, the result could not represent the entire cases. However, we confirmed that patient's radiation dose in some cases exceeded the recommendation and the deviation between hospitals was observed. To improve this issue, doctors of diagnostic imaging or technologists of radiology should perform CT by the optimized protocol to decrease a level of CT radiation and also reveal radiation dose for the right to know of patients. However, they had little understanding of the situation. Therefore, the effort of relevant agencies with education program for CT radiation dose, release of radiation dose from CT examination and addition of radiation dose control and open CT contents into evaluation for hospital services and certification, and also the effort of health professionals with the best protocol to realize optimized CT examination.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.66-71
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• 2019

In this paper, a study was conducted on the method of using GPR data to predict rebar thickness inside a facility. As shown in the cases of poor construction, such as the use of rebars below the domestic standard and the construction of reinforcement, information on rebar thickness can be found to be essential for precision safety diagnosis of structures. For this purpose, the B-scan data of GPR was obtained by gradually increasing the diameter of rebars by making specimen. Because the B-scan data of GPR is less visible, the data was converted into the heatmap image data through migration to increase the intuition of the data. In order to compare the results of application of commonly used B-scan data and heatmap data to CNN, this study extracted areas for rebars from B-scan and heatmap data respectively to build training and validation data, and applied CNN to the deployed data. As a result, better results were obtained for the heatmap data when compared with the B-scan data. This confirms that if GPR heatmap data are used, rebar thickness can be predicted with higher accuracy than when B-scan data is used, and the possibility of predicting rebar thickness inside a facility is verified.

• Journal of Korean Foot and Ankle Society
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• v.22 no.2
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• pp.62-67
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• 2018

Purpose: To evaluate the clinical significance and usefulness of a bone scan in accessory navicular bone. Materials and Methods: Eighty-five patients with foot pain and accessory navicular bone on radiography, who underwent bone scan from 2012 to 2015, were analyzed retrospectively. The subjects was divided into a symptomatic and asymptomatic group according to the presence of navicular bone tenderness. The grade of bone scan uptake was divided into 3 grades. Age, gender, grade of bone scan and size of the accessory navicular bone were analyzed. The symptomatic group were divided into a low (grade 0, 1) and high uptake (grade 2) group to determine the appropriate treatment. The low uptake group was treated conservatively for 3 months. The high uptake group was initially treated conservatively for 3 months and surgery was performed if pain persisted. For the clinical evaluation, the visual analogue scale, American Orthopaedic Foot and Ankle Society midfoot scale were evaluated in the first examination and last follow-up date. The patient's satisfaction grade was also evaluated at the last follow-up. Results: The asymptomatic group mostly showed no uptake in the bone scan. On the other hand, some patients in the asymptomatic group showed an increase in uptake. In these patients, the size of accessory navicular bone was related to the grade of bone scan uptake, showing that the bone scan uptake grade can be predicted when applying different cut off values for the bone size. The symptomatic group mostly showed uptake in the bone scan and the grade of uptake had a positive correlation with the size of the accessory navicular bone (p<0.05). Age and gender were not related to the bone scan uptake. In the clinical evaluation, conservative and surgical treatment showed a good outcome. Conclusion: The bone scan uptake grade alone cannot be used to completely predict the symptoms. On the other hand, the size of the accessory bone can increase the bone scan uptake. Therefore, the size of the accessory bone, and patient symptoms should be considered in patients with a high uptake when deciding treatment.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1924-1937
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• 1996

In this paper, we propose a ESP(Extended Scan Path) architecture for multi- board testing. The conventional architectures for board testing are single scan path and multi-scan path. In the single scan path architecture, the scan path for test data is just one chain. If the scan path is faulty due to short or open, the test data is not valid. In the multi-scan path architecture, there are additional signals in multi-board testing. So conventional architectures are not adopted to multi-board testing. In the case of the ESP architecture, even though scan paths either short or open, it doesn't affect remaining other scan paths. As a result of executing parallel BIST and IEEE 1149.1 boundary scan test by using, he proposed ESP architecture, we observed to the test time is short compared with the single scan path architecture. Because the ESP architecture uses the common bus, there are not additional signals in multi-board testing. By comparing the ESP architecture with conventional one using ISCAS '85 bench mark circuit, we showed that the architecture has improved results.