• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.25-28
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• 2011

Purpose: The aim of study is to find accuracy of pocket dosimeter in measuring exposed dose in compared with survey meter and to compare exposed dose according as Nuclear medicine exams. Materials and Method: First, radiation dose to point source(185 MBq,370 MBq, ${\ldots}$, 1665 MBq, 1850 MBq) were measured in using a pocket dosimeter and a survey meter. Second, radiation dose to 12 patients injected $^{18}F$-FDG 370 MBq were measured in using a pocket dosimeter and a survey meter. Third, radiation dose to 10 patients injected $^{99m}Tc$-DPD 925 MBq were measured in using a pocket dosimeter and a surveymeter. Result: The average is $70.12{\pm}39.36{\mu}Sv/h$ in measurement of point source with Surveymeter and $5{\pm}3.06{\mu}Sv$ in measurement of point source with Pocket dosimeter. The average is $25.04{\pm}6.16{\mu}Sv/h$ in measurement of PET/CT patients with Surveymeter and $2.41{\pm}0.51{\mu}Sv$ in measurement of PET/CT with Pocket dosimeter. The average is $8.58{\pm}0.96{\mu}Sv/h$ in measurement of Bone Scan patients with Surveymeter and $1{\mu}Sv$ in measurement of Bone Scan patients with Pocket dosimeter. Significant difference found between Survey meter value and Pocket dosimeter value in all experimentation (p<0.001). Conclusion: Accoring to rusult Wearing Pocket dosimeter is usefulnee in manerage of exposed dose in nucler medicine exams.

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.60-66
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• 2003

Purpose : Neonatal hydronephrosis has been detected with increasing frequency with the widespread use of prenatal ultrasonography, but the consensus about its postnatal management has not yet been reached, especially about surgical intervention. We attempted to determine the guideline of follow-up study and surgical intervention of hydronephrosis by analyzing clinical outcomes of neonates with hydronephrosis. Materials and Methods : Between 1994 and 2000, 128 hydronephrotic kidneys were postnatally confirmed. Cases associated with other urologic anomalies were excluded and 90 unilateral hydronephrotic kidneys with a minimum follow-up of 12 months were enrolled in this study. We classified the patients into 6 groups according to the anterior posterior pelvic diameter(APPD) at initial ultrasonography(USG) within 1 month after birth. Renal USG and $Tc^{99m}-mercaptoacetyl$ triglycerine(MAG3) scan were done according to a set protocol, and pyeloplasty was performed when indicated according to our protocol. Results : Most cases whose APPD were below 10 mm improved or resolved. Only few cases with APPD above 20 mm showed spontaneous improvement and most(88%) had undergone operation. Those with initial APPD within 10-19 mm showed variable outcomes. When the risk factors for irreversible renal functional deterioration were analyzed, the age at pyeloplasty and pre-operative functional deficit were significant. Conclusion : We concluded that in infants with initial APPD below 10 mm, consideration of surgery is not needed, and in those with initial APPD above 20 mm, early operation is recommended. Our set protocol based on initial USG is useful, but the cut-off value of relative renal function(RRF) for operation might be increased to 40% to improve post operative RRF.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.364-370
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• 2001

Purpose: In the revascuarization of ischemic dysfunctional myocardium, stunned myocardium was reported to recover function earlier than hibernating myocardium. It was also suggested that stunning and hibernation could be discriminated by reversibility of perfusion impairment on myocardial SPECT. In this study, we investigated the time course of functional recover after CABG according to reversibility of perfusion impairment. Materials and Methods: In 92 patients with coronary artery disease, Tl-201 rest/dipyridamole stress Tc-99m-MIBI gated SPECT was performed before, 3 months after, and 17 months after CABG. Using a 20-segment model, segmental perfusion and systolic thickening were automatically quantified. Perfusion-impaired segments with abnormal thickening were classified by reversibility into reversible (REV) and irreversible (IRREV) groups. The proportions of function-recovered segments were compared between groups and also between 3 months and 17 months in each group. Results: A total of 129 segments were Included In the analysis, and 76 were REV and 53 were IRREV. At 3 months after CABG, 61 segments (80%) in REV group showed functional recovery while 28 segments (53%) in IRREV group did (p<0.001). However, at 17 months after CABG, 60 segments (79%) in REV group and 37 segments (70%) un IRREV group showed functional recovery (p=n.s.). When comparing 3 months and 17 months in each group, REV group showed no difference, while IRREV group showed significant further improvement (p<0.05). Conclusion: In viable myocardium with ischemic myocardial dysfunction, the segments with reversible perfusion impairment recover function earlier after revascularization than irreversible segments.

• The Korean Journal of Nuclear Medicine
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• v.29 no.4
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• pp.511-517
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• 1995

Bone scan is a very sensitive diagnostic imaging test for detecting bone and joint disorders. So it might be useful in the diagnosis of temporomandibular disorders of the joint origin. Thus, the effectiveness of bone scan for detecting temporomandibular joint(TMJ) diseases and differentiating the TMJ disc displacement from the TMJ arthritis was evaluated. Bone scan was done in 21 patients with TMJ disc displacement(13 unilaterally affected, 8 bilaterally affected), 25 patients with TMJ arthritis(23 unilateral, 3 bilateral), and 39 volunteers with no signs, symtoms, or history of TMJ disease. TMJ simple uptake rate(SUR) and difference of both TMJ SUR were calculated from the 100,000 count lateral image of head and neck region in 99mTc MDP bone scan. Transcranial and panorama X-ray examination was also done in all patients. TMJ SUR(%) were $1.673{\pm}0.606$ in TMJs affected with arthritis, $1350{\pm}0.351$ in TMJs affected with disc displacement, and $1.084{\pm}0.172$ in TMJs of controls. Significant differences were demonstrated among them(p<0.01) Difference of bith TMJ SUR was highest in patients with unilateral TMJ arthritis($0.608{\pm}$0.533, p<001), and there is no significant difference between that of controls and that of unilateral TMJ dist displacement patients($0.062{\pm}0.063$ vs $0.122{\pm}0.100$). TMJ SUR of Joint with bone change on X-ray finding was not significantly different from that of joint with normal X-ray finding. Those in patients with unilateral TMJ disc displacement(696% and 87% vs 23.1% and 23%). The proportions of patients with increased TMJ SUR and difference of both TMJ SUR(>mean+2SD of controls) in unilateral TMJ arthritis patients were significantly higher than those in patients with unilateral TMJ disc displacement(69.6% and 87% vs 23.1% and 23%). Conclusively, bone scan nay help to detect TMJ disease and differentiate TMJ disc displacement from TMJ arthritis.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.149-152
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• 2014

Purpose: At our hospital blood is collected from a patient before an imaging test, with the concern of any effect possible when a nuclear medicine imaging test and an in-vitro test are carried out at the same time. However, occasionally, the blood collection is performed after an imaging test, with the reasons that the patient is not properly guided or the patient doesn't follow the guide correctly. In that case, we prefer to gather blood again after a few days. The purpose of this study is not only to see whether there is any effect of an imaging test on the result of the in-vitro test performed with the blood collected after the imaging test, but also to study how many days waiting after each test is appropriate to take a blood sample, if the effect exists. Materials and Methods: From September to October 2013, blood were collected from 13 patients in our hospital regardless of age and sex each time before and after the injection of the radioactive isotope from the tests : PET-CT, Gated Myocardial SPECT, and DTPA GFR Scan. Considering a half-life, AFP, CA19-9, CEA, TSH, and T3 were carried out right after the blood collection. In case of an iodine therapy, blood were taken each time before and after taking radioactive iodine, and, after AFP, CA19-9, and CEA, the difference between them in consistency and in cpm were compared. Results: With 10 patients after the imaging tests and 3 patients after the iodine therapy, their serum cpm was over 10,000. Over time, the cpm decreased in accordance with the half-life ($^{18}F$ 110minutes, $^{99}mTc$ 6hours, $^{201}Tl$ 72hours, $^{131}I$ 7days). Between the two cases, one before and the other after the injection of the radioactive isotope, the cpm and the results of AFP, CA19-9, CEA, TSH, and T3 from three patients each test, PET-CT, Gated Myocardial SPECT, and DTPA GFR Scan, were very similar. In addition, in case of an iodine therapy, there was also not a meaningful difference in the cpm and the results of AFP, CA19-9, and CEA, from three patients in an iodine therapy, between the two cases, one before and the other after taking the radioactive iodine. Conclusion: In case a blood collection was performed after the imaging test which required a radioactive isotope injection, the cpm increased, differently according to the kind of the radioactive isotope. However, the results of the in-vitro tests like AFP, CA19-9, CEA, TSH, T3, etc were nearly not affected. As the result, it's considered that there will not be any significant effect also from other tests, as the result from the performed seven tests.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.268-273
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• 2006

차세대 무선 네트워크 (4G)는 새로운 무선 접속 기술의 개발과 함께 많은 연구가 필요한 분야이다. 그 중에서 특히 단말의 끊김없는 이동성을 제공해 주기 위한 핸드오버 기술이 가장 중요하다고 할 수 있다. 차세대 무선 네트워크는 새로운 무선 접속 기술과 함께 기존의 무선랜이나 이동통신망 등과 같이 사용될 것으로 예상되며, 네트워크 계층에서의 이동성 지원을 위하여 Mobile IPv6를 사용할 것으로 예상되는 네트워크이다. 이러한 네트워크에서 끊김없는 이동성을 제공해 주기 위해서는 현재까지 연구된 핸드오버 기능 및 구조에 대한 연구와 함께 보다 다양해진 네트워크 환경과 QoS 등을 고려한 종합적인 핸드오버 기능에 대한 연구가 필요하다. 본 논문에서는 차세대 무선 네트워크에서 단말의 끊김없는 핸드오버를 제공해 주기 위하여 필요한 기능들을 도출하고, 이들간의 유기적인 연관관계를 정의하여 다양한 네트워크 환경과 사용자의 우선순위, 어플리케이션의 QoS 요구 조건 등을 고려한 종합적인 핸드오버 기능 구조를 제안하고자 한다. 제안하는 핸드오버 구조는 Monitoring, Triggering, Handover의 세 가지 module로 나뉘어져 있으며, 각각은 필요에 따라 sub-module로 다시 세분화된다. 제안하는 핸드오버 구조의 가장 큰 특징은 핸드오버를 유발시킬 수 있는 여러 가지 요소를 종합적으로 고려하며 이들간의 수평적인 비교가 아닌 다단계 비교를 수행하여 보다 정확한 triggering이 가능하도록 한다. 또한 단말의 QoS 요구 사항을 보장하고 네트워크의 혼잡도(congestion) 및 부하 조절 (load balancing)을 위한 기능을 핸드오버 기능에 추가하여 효율적인 네트워크의 자원 사용이 가능하도록 설계하였다.서버로 분산처리하게 함으로써 성능에 대한 신뢰성을 향상 시킬 수 있는 Load Balancing System을 제안한다.할 때 가장 효과적인 라우팅 프로토콜이라고 할 수 있다.iRNA 상의 의존관계를 분석할 수 있었다.수안보 등 지역에서 나타난다 이러한 이상대 주변에는 대개 온천이 발달되어 있었거나 새로 개발되어 있는 곳이다. 온천에 이용하고 있는 시추공의 자료는 배제하였으나 온천이응으로 직접적으로 영향을 받지 않은 시추공의 자료는 사용하였다 이러한 온천 주변 지역이라 하더라도 실제는 온천의 pumping 으로 인한 대류현상으로 주변 일대의 온도를 올려놓았기 때문에 비교적 높은 지열류량 값을 보인다. 한편 한반도 남동부 일대는 이번 추가된 자료에 의해 새로운 지열류량 분포 변화가 나타났다 강원 북부 오색온천지역 부근에서 높은 지열류량 분포를 보이며 또한 우리나라 대단층 중의 하나인 양산단층과 같은 방향으로 발달한 밀양단층, 모량단층, 동래단층 등 주변부로 NNE-SSW 방향의 지열류량 이상대가 발달한다. 이것으로 볼 때 지열류량은 지질구조와 무관하지 않음을 파악할 수 있다. 특히 이러한 단층대 주변은 지열수의 순환이 깊은 심도까지 가능하므로 이러한 대류현상으로 지표부근까지 높은 지온 전달이 되어 나타나는 것으로 판단된다.의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$-transierrin이 감염 병소의 영상진단에 사용될 수 있을 것으로 기대된다.리를 정량화 하였다. 특히 선

• Progress in Medical Physics
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• v.7 no.1
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• pp.65-77
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• 1996

Using the 2-D and 3-D Hoffman brain phantom, 3-D Jaszczak phantom and Single Photon Emission Computed Tomography, the effects of data acquisition parameter, attenuation, noise, scatter and reconstruction algorithm on image quantitation as well as image quality were studied. For the data acquisition parameters, the images were acquired by changing the increment angle of rotation and the radius. The less increment angle of rotation resulted in superior image quality. Smaller radius from the center of rotation gave better image quality, since the resolution degraded as increasing the distance from detector to object increased. Using the flood data in Jaszczak phantom, the optimal attenuation coefficients were derived as 0.12cm$\^$-1/ for all collimators. Consequently, the all images were corrected for attenuation using the derived attenuation coefficients. It showed concave line profile without attenuation correction and flat line profile with attenuation correction in flood data obtained with jaszczak phantom. And the attenuation correction improved both image qulity and image quantitation. To study the effects of noise, the images were acquired for 1min, 2min, 5min, 10min, and 20min. The 20min image showed much better noise characteristics than 1min image indicating that increasing the counting time reduces the noise characteristics which follow the Poisson distribution. The images were also acquired using dual-energy windows, one for main photopeak and another one for scatter peak. The images were then compared with and without scatter correction. Scatter correction improved image quality so that the cold sphere and bar pattern in Jaszczak phantom were clearly visualized. Scatter correction was also applied to 3-D Hoffman brain phantom and resulted in better image quality. In conclusion, the SPECT images were significantly affected by the factors of data acquisition parameter, attenuation, noise, scatter, and reconstruction algorithm and these factors must be optimized or corrected to obtain the useful SPECT data in clinical applications.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.141-149
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• 2012

The aims of this study are to assess external radiation exposed doses of body and hands of nuclear medicine workers who handle radiation sources, and to measure radiation exposed doses of the hands induced by a whole body bone scan with high frequency and handling a radioactive sources like $^{99m}Tc$-HDP and $^{18}F$-FDG in the PET/CT examination. Skillful workers, who directly dispense and inject from radiation sources, were asked to wear a TLD on the chest and ring finger. Then, radiation exposed dose and duration exposed from daily radiation sources for each section were measured by using a pocket dosimeter for the accumulated external doses and the absorbed dose to the hands. In the survey of four medical institutions in Incheon Metropolitan City, only one of four institutions has a radiation dosimeter for local area like hands. Most of institutions uses radiation shielding devices for the purpose of protecting the body trunk, not local area. Even some institutions were revealed not to use such a shielding device. The exposed doses on the hands of nuclear medicine workers who directly handles radioactive sources were approximately twice as much as those on the body. The radiation exposure level for each section of the whole body bone scan with high frequency and that of the PET/CT examination showed that radiation doses were revealed in decreasing order of synthesis of radioactive medicine and installation to a dispensing container, dispensing, administering and transferring. Furthermore, there were statistically significant differences of radiation exposure doses of the hands before and after wearing a syringe shielder in administration of a radioactive sources. In this study, although it did not reach the permissible effective dose for nuclear medicine, the occupational workers were exposed by relatively higher dose level than the non-occupational workers. Therefore, the workers, who closely exposed to radioactive sources should be in compliance with safety management regulations, and take actions to maximally reduce locally exposed dose to hands monitoring with ring TLD.

• Childhood Kidney Diseases
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• v.10 no.1
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• pp.33-39
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• 2006

Purpose : Neonatal hydronephrosis is diagnosed with an incidence of 4.5-7% of pregnancies. Recently, early detection of neonatal hydroneprosis with antenatal ultrasonography has be-come possible. But consensus about its management has not been reached, especially concerning surgical intervention. The purpose of this study is to analyze the natural course of neonatal hydronephrosis and to determine the guideline of surgical intervention and follow up study. Methods : Sixty nine hydronephrotic kidneys were confirmed from April 2001 to April 2005. All cases were rechecked by ultrasonography once at least and had a minimum follow-up of 6 months. We classified the patients into 4 groups according to the anterior posterior pelvic diameter(APPD) on perinatal ultrasonography. Ultrasonography to measure the APPD diameter and Society for Fetal Urology(SFU) grade, $^{99m}Tc-MAG3$ scan were done to a set protocol. Pyeloplasty was peformed according to the protocol. Results : Pyeloplasty was not needed in most cases where the APPD was below 10 mm and where the SFU grade were less than grade 3. Many cases with APPD 10 mm above or SFU grade III above had undergone pyeloplasty. We found a correlation between obstruction grade on MAG3 scan and whether surgery was performed or not. Conclusion : If APPD is above 10 mm, SFU grade is above grade 3 or urinary tract obstruction is suspected by MAG3 scan, pyeloplasty must be considered. In cases where APPD is below 10mm and SFU grade is less than grade 3, we can observe the natural course of neonatal hydronephrosis with consecutive follow-up. (J Korean Soc Pediatr Nephrol 2006;10:33-39)

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.181-188
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• 2003

Purpose : Vesicoureteral reflux(VUR) is known to be the main cause of childhood hypertension and renal failure. Knowing its familial occurrence, we determined the incidence of VUR and renal scar in asymptomatic siblings of Korean patients with primary VUR Methods : A total of 50 siblings from 37 index patients were included. Voiding cystourethro-graphy(VCUG) and renal scintigraphy using $^{99m}Tc-DMSA$ were peformed in these siblings from June, 1994 to May, 2001, Index patients were classified into two groups according to the presence of VUR in their siblings, and the clinical factors of the index patients such as age, sex, grade of reflux and renal cortical defect were compared between the groups. Results : Among the 50 siblings, VUR were found in 8(16%) and renal cortical defects were detected in 8(16%) siblings respectively. The incidence of renal cortical defects was 87.5%(7 out of 8) in the VUR(+) siblings. There was a case of VUR(-) cortical defect in one sibling, presumed as a scar from an old VUR. There was no relationship among age, sex, grade of reflux and renal cortical defect of the index patient to the presence of VUR in siblings. Conclusion : This study confirmed a significant incidence of VUR(16%) and renal cortical defects(16%) in the asymptomatic siblings of patients with primary VUR in Korea. It Is resonable to recommend screening studies to the siblings of patients with VUR for the early detection and prevention of probable reflux nephropathy. (J K orean Soc Pediatr Nephrol 2003;7:181-188)