• Proceedings of the Korean Society of Medical Physics Conference
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• 2005.04a
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• pp.71-74
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• 2005

To introduce the four-dimensional computed tomography (4DCT, Light Speed RT, General Electric, USA) scanner newly installed in our department and evaluate its feasibility for gated radiotherapy. Respiratory signal measured by real-time position management (RPM$^{\circledR}$, Varian Medical, USA) was recorded in synchronization with the 4DCT scanner. 4DCT data were acquired in axial cine mode and sorted retrospective image based on respiratory phase. PTVs delineated from helical CT and 4DCT images were compared. The PTV delineated from conventional helical CT images was 2 cc larger than that from 4DCT images. Dose in PTV of the plan from retrospective CT was 99.3% (minimum=72.0%, maximum=106.5%) and that of helical CT plan was 95.2% (minimum=24.1%, maximum=106.4%) of prescribed dose. Comparing with DVHs of both plan, the coverage for 4CDT plan was 3.7% improved. It is expected that 4DCT could improve tumor control and reduce radiation toxicity for liver cancer.

• The Korean Journal of Pain
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• v.8 no.2
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• pp.286-292
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• 1995

Buerger's disease(Thromboangiitis Obliterans) is characterized by peripheral arterial occlusion of the extremities in young smokers, and leading to ischemia of the tissue and gangrene. Most of these patients suffered from severe pain. therapy for Buerger's disease not enable to undergo reconstructive arterial surgery has been discouraging while multiple modes of analgesics have advanced. Eight subjects who had been operated due to Buerger's disease or diagnosed with this disease were evaluated retrospectively. Continuous epidural block was done at L 2~3 or L3~4 intervertebral space and multiday continuous infusor was connected to epidural catheter. The content of the infusor was clonidine-bupivacaine or clonidine-morphine-bupivacaine mixture. The minimum dose of clonidine was 75 ${\mu}g/day$ and the maximum 450 ${\mu}g/day$. The results were as follows: The analgesia produced by clonidine was superior to any other analgesics. 2) The incidence of the side effects produced by clonidine-bupivacaine mixture were less than that of clonidine-morphine-bupivacaine mixture. 3) Minimum dose of clonidine for the pain relief was required more than 225 ${\mu}g$ per day. From the above results, we recommend that clonidine is an effective agent to provide pain relief for the patients with Buerger's disease.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.2
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• pp.99-109
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• 2023

Purpose: CT scan makes up for the weak point of the nuclear medicine image having a low resolution and also were used for attenuation correction on image reconstruction. Recently, many studies try to make use of CT images additionally, one of them is to measure the bone mineral density(BMD) using Quantitative CT(QCT) software. BMD exams are performed to scan lumbar and femur with DXA(Dual-Energy X-Ray Absorptiometry) in order to diagnose bone disease such as osteopenia, osteoporosis. The purpose of this study is to identify the usefulness of QCT_BMD analyzed with low dose CT images on L-spine Bone SPECT/CT comparing with DXA_BMD. Materials and Methods: Fifty five women over 50 years old (mean 66.4 ± 9.1) who took the both examinations(L-spine Bone SPECT/CT with SIEMENS Intevo 16 and DXA scan with GE Lunar prodigy advance) within 90 days from April 2017 to July 2022, BMD, T-score and disease classification were analyzed. Three-dimensional BMD was analyzed with low dose CT images acquired on L-spine Bone SPECT/CT scan on Mindways QCT PRO^TM software and two-dimensional BMD was analyzed on DXA scan. Basically, Lumbar 1-4 were analyzed and the patients who has lesion or spine implants on L-spine were excluded for this study. Pearson's correlation analysis was performed in BMD and T-score, chi-square test was performed in disease classification between QCT and DXA. Results: On 55 patients, the minimum of QCT_BMD was 18.10, maximum was 166.50, average was 82.71 ± 31.5 mg/cm³. And the minimum of DXA-BMD was 0.540, maximum was 1.302, average was 0.902 ± 0.201 g/cm², respectively. The result shows a strong statistical correlation between QCT_BMD and DXA_BMD(p<0.001, r=0.76). The minimum of QCT_T-score was -5.7, maximum was -0.1, average was -3.2 ± 1.3 and the minimum of DXA_T-score was -5.0, maximum was 1.7, average was -2.0 ± 1.3, respectively. The result shows a statistical correlation between QCT T-score and DXA T-score (p<0.001, r=0.66). On the disease classification, normal was 5, osteopenia was 25, osteoporosis was 25 in QCT and normal was 10, osteopenia was 25, osteoporosis was 20 in DXA. There was under-estimation of bone decrease relatively on DXA than QCT, but there was no significant differences statistically by chi-square test between QCT and DXA. Conclusion: Through this study, we could identify that the QCT measurement with low dose CT images QCT from L-Spine Bone SPECT/CT was reliable because of a strong statistical correlation between QCT_BMD and DXA_BMD. Bone SPECT/CT scan can provide three-dimensional information also BMD measurement with CT images. In the future, rather than various exams such as CT, BMD, Bone scan are performed, it will be possible to provide multipurpose information via only SPECT/CT scan. In addition, it will be very helpful clinically in the sense that we can provide a diagnosis of potential osteoporosis, especially in middle-aged patients.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1033-1039
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• 2023

Low-dose chest CT, which is used as a lung screening test, also includes information on coronary artery calcification within the scan range. The purpose of this study was to investigate the usefulness of determining coronary artery calcification using Low-dose chest CT. Those who underwent low-dose chest CT and coronary artery calcification score CT on the same day were eligible. Coronary artery calcium score CT results were divided into 4 groups (Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS) by referring to the Coronary artery calcium score categories and risks. After selecting 30 people each group, five radiotechnologists with more than 15 years of experience in coronary artery calcium measurement retrospectively analyzed the presence or absence of coronary artery calcification in low-dose chest CT images. The results of the five observers' uniform interpretation of the low-dose chest CT image were consistent with the coronary artery calcium score CT results in Low group: 56%, Mild group: 96.6%, Moderate group: 100%, and High group: 100%. appeared. In the Low group, all 5 observers observed calcification in 17 out of 30 cases, and in 7 cases all 5 observers decided that calcification could not be identified. Coronary artery calcification could be observed in 100% of asymptomatic adults with a calcium score of 15 or higher in low-dose chest CT scans. The minimum calcium score that can be identified is 1, and it was found that even very small calcifications can be identified when the subject's body size is small or the scan is performed at a time when heart movement is minimal.

• The Korean Journal of Pain
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• v.5 no.1
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• pp.29-36
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• 1992

This study was objected to evaluate clinical progressions about both the degree of pain relief and the occurrence of morphine tolerance while the epidural analgesia with low dose of morphine, bupivacaine and antidepressant continued repeatedly at every 5 day intervals of the constant-rate infusion(0.5 ml/hr, 60 ml capacity). The subjects were divided to 56 cancer and 36 non-cancer patients who failed to respond to palliative treatments. Before the relief of pain, the pain severity was moderate(10%) and severe(90%). The dose escalation of morphine noted to 11(20%)patients in cancer pain and to one(5%) case only in non-cancer. During the epidural analgesia, the effect of pain relief was moderate(11%) and good(89%). It suggest that the morphine tolerance may be reduced to some degree such as an initial minimum dose of epidural morphine with local anesthetic and antidepressant should be adjusted on an individual basis using the constant-rate infusor, even though rapid dose escalation occurrs in some patients who the diseases progress over a short period of time.

• Korean Journal of Veterinary Research
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• v.48 no.3
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• pp.267-274
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• 2008

This study was to evaluate the efficacy of single dose Mycoplasma hyopneumoniae (M. hyo)-vaccination in the swine farms which had different serological patterns of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). A minimum of 240 pigs from each farm was applied, allocating M. hyo vaccinated and control groups. The PRRSV and PCV2 infections were analyzed by serological method (commercial ELISA kit). After administrating pigs a single dose of M. hyo vaccine or control saline at 3 weeks of age, serum antibodies to M. hyo, PRRSV and PCV2 were monitored at 4, 10, 16 and 22 weeks of age. Mortality, weight changes, feed conversion ratio (FCR) and lung score were also evaluated. A single-dose vaccination of M. hyo bacterin was efficacious to reduce mycoplasmal lung lesions and induce good humoral immune response. However, FCR was improved only in one of the three farms where showed seronegative status to both PRRSV and PCV2 in the period from 4 to 16 weeks of age. These results might imply that M. hyo vaccine alone could not overcome the PRRSV and PCV2 infection-associated wasting in the field condition. Therefore, the control of PRRSV and PCV2 should be considered to obtain the better effects of M. hyo vaccination.

• Journal of The Korean Dental Society of Anesthesiology
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• v.2 no.2 s.3
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• pp.97-100
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• 2002

Background: Patient-controlled sedation (PCS) has been blown for a safe and effective sedative method on the same pharmacological concepts of patient-controlled analgesia. Many different kinds of infusion devices have been used but they often have too long nominal infusion rate and lockout time. $Perfuser^{\circledR}$ fm (B. Braun, Germany) is a new PCA device with 999.9 ml/hr nominal infusion rate and minimum 1 min lockout time. In this study, the feasibility of propofol PCS using $Perfuser^{\circledR}$ fm was examined in order to provide a safe satisfactory sedation for dental patients. Methods: Eleven healthy patients presenting for oral surgery were studied. Propofol PCS was performed using $Perfuser^{\circledR}$ fm, which was set to deliver a bolus dose of 5 mg with 999.9 ml/hr nominal infusion rate and 1 min lockout time. Propofol loading dose was randomly assigned to a bolus dose ${\times}$ 0, 2, and 3 (initial bolus). Patients were told to press the bolus button as often as they needed to relieve discomfort. Results: Total infused dose of propofol was mean 1.8 mg/kg/hr and D (Delivery)/A (Attempt) ratio was mean 72.8%. All patients was awake and there were no clinically significant intraoperative side effects during the sedation. Almost all patients were very satisfied with this type of PCS. Conclusion: Propofol PCS using $Perfuser^{\circledR}$ fm infusion pump provided good conscious sedation for dental procedures.

• Progress in Medical Physics
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• v.27 no.3
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• pp.162-168
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• 2016

Proton therapy is increasingly being actively used in the treatment of cancer. In contrast to photons, protons have the potential advantage of delivering higher doses to the cancerous tissue and lower doses to the surrounding normal tissue. However, a range shifter is needed to degrade the beam energy in order to apply the pencil beam scanning technique to tumors located close to the minimum range. The secondary neutrons are produced in the beam path including within the patient's body as a result of nuclear interactions. Therefore, unintended side effects may possibly occur. The research related to the secondary neutrons generated during proton therapy has been presented in a variety of studies worldwide, since 2007. In this study, we measured the magnitude of the secondary neutron dose depending on the location of the detector and the use of a range shifter at the beam nozzle of the proton scanning mode, which was recently installed. In addition, the production of secondary neutrons was measured and estimated as a function of the distance between the isocenter and detector. The neutron dose was measured using WENDI-II (Wide Energy Neutron Detection Instruments) and a Plastic Water phantom; a Zebra dosimeter and 4-cm-thick range shifter were also employed as a phantom. In conclusion, we need to consider the secondary neutron dose at proton scanning facilities to employ the range shifter reasonably and effectively.

• Nuclear Engineering and Technology
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• v.49 no.8
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• pp.1752-1757
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• 2017

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration ($A_c$), minimum detectable activity, absorbed gamma dose rate, external hazard index ($H_{ex}$), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index ($H_{ex}$ and $H_{in}$, respectively) were estimated based on the measured radionuclide concentration of the $^{238}U$($^{226}Ra$) and $^{232}Th$ decay chains and $^{40}K$. The activity concentrations of the $^{238}U$, $^{232}Th$ decay series and $^{40}K$ of these samples varied from $45.11{\pm}3.1Bq/kg$ to $252.38{\pm}34.3Bq/kg$, from $64.65{\pm}6.1Bq/kg$ to $579.84{\pm}53.1Bq/kg$, and from $403.36{\pm}20.8Bq/kg$ to $527.47{\pm}23.1Bq/kg$, respectively. The activity concentration of $^{232}Th$ in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from $99.86{\mu}Sv/y$ to $612.31{\mu}Sv/y$, which are higher than the world average values of 59 nGy/h and $70{\mu}Sv/y$, respectively. The $H_{ex}$ values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of $H_{ex}$ for Sample 1 is significantly higher than the international acceptable limit of <1. The results are tabulated, depicted, and discussed within national and international frameworks, levels, and approaches.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.705-711
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• 2019

Currently, the brain CT scan of the latest equipment lacks the study of parameter change and dose change and especially of noise, uniformity analysis and dose change. Therefore, this study attempted to study the phenomenon that occurs at this time by analyzing tube voltage, slice thickness, and pitch change in exposure parameters when using high specification CT. Experimental results show that uniformity is better when using high voltage, thick slice thickness selection, and minimum pitch. As a result of the combination, the most uniformity condition was 140 kVp, 10 mm and pitch 0.5. Noise was found to be improved regardless of pitch by increasing tube voltage and slice thickness. The radiation dose increased linearly with tube voltage and pitch. Therefore, the results of this study will serve as a reference for the use of High specification brain CT.