• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.4
• /
• pp.275-284
• /
• 2008

Purpose: We intended to evaluate myocardial oxygen consumption ($MVO_2)$ by applying recirculation correction and modified one-compartment model to have a reference range of $MVO_2$ in normal young population and to reveal the effect of recirculation on time-activity curve (TAC). Materials and Methods: In nine normal male volunteers with mean age of $26.3{\pm}4.0$, $MVO_2$ was estimated with 925 MBq (25mCi) of $^{11}C$-Acetate (Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, Korea) and PET/CT (Biograph 6, Siemens Medical Solution, Germany). Analysis software such as $MATLAB^{(R)}$ v7.1 (Mathworks, Inc., United States), $Excel^{(R)}$ 2007 (Microsoft, United States), and $SPSS^{(R)}$ v12.0 (Apache Software Foundation, United States) were used. Twenty three frames were of $12{\times}10$, $5{\times}60$, $3{\times}120$, $2{\times}300's$ duration, respectively. The modified one-compartmental model and the recirculation correction method were applied. Statistical analysis was performed by using Test of Normality, ANOVA and Post-Hoc (Scheffe's) analysis, and p-value less than 0.05 was considered as significant. Results: The normal reference ranges of $MVO_2$ were presented as $3.18-4.64\;{\times}\;10^{-4}\;ml/g/sec$, $1.91-3.94\;{\times}\;10^{-4}\;ml/g/sec$, $4.31-6.40\;{\times}\;10^{-4}\;ml/g/sec$, $2.84-4.53\;{\times}\;10^{-4}\;ml/g/sec$ and $3.42-5.00\;{\times}\;10^{-4}\;ml/g/sec$ in the septum, the inferior wall, the lateral wall, the anterior wall and the entire wall, respectively. In addition, it was noted that the dual exponentiality of the clearance curve is due to the recirculation effect and that the characteristic of the curve is essentially mono-exponential. Conclusion: $^{11}C$-Acetate is a radiotracer worthwhile to assess $MVO_2$. Re-circulated $^{11}C$ can influence TAC of $^{11}C$ in myocadia and so the recirculation correction must be considered when measuring $MVO_2$.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.4
• /
• pp.292-300
• /
• 2008

Purpose: Our purpose was to evaluate F-18 FDG uptake in pulmonary lymphangitic carcinomatosis (PLC) according to CT findings and histology of lung cancer. Materials and Methods: Thirty-three lung cancer patients with PLC were enrolled in this retrospective study. All the patients had a CT-based diagnosis of PLC. Chest CT findings of PLC were classified on the basis of involvement of axial interstitium. We categorized the involvement of axial interstitium as group 1, and the involvement of peripheral interstitium only as group 2. Visual and semiquantitative analyses by F-18 FDG PET/CT were performed in the PLC lesions. At first, we analyzed the F-18 FDG uptake in the PLC by visual assessment. If abnormal uptake was seen in the PLC, we drew regions of interest in the PLC lesions to obtain the maximum SUVs (maxSUVs). Results: Of the 33 patients, 22 had abnormal F-18 FDG uptake in the visual assessment. There was no significant difference in the frequency of abnormal F-18 FDG uptake between group 1 and group 2 (p=0.17), although the frequency of group 1 tended to be higher than group 2 (15/19 (78.9%) in group 1, 7/14 (50.0%) in group 2). However, group 1 had a higher maxSUV than group 2 (p<0.01, group 1: $2.9{\pm}1.4$, group 2: $1.5{\pm}0.6$). There was no significant difference in the frequency of abnormal F-18 FDG uptake and maxSUV among the histology of the lung cancers. Conclusion: The involvement of axial interstitium in the PLC by lung cancer has a higher maxSUV than the involvement of only peripheral interstitium.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.4
• /
• pp.314-322
• /
• 2008

Purpose: It is widely recognized that good quality control (QC) program is essential for adequate imaging diagnosis using gamma camera. The purpose of this study is to survey the current status of QC of gamma cameras in Republic of Korea for implementing appropriate nationwide quality control guidelines and programs. Methods: A collection of data is done for personnel, equipment and appropriateness of each nuclear medicine imaging laboratory's quality control practice. This survey is done by collection of formatted questionnaire by mails, emails or interviews. We also reviewed the current recommendations concerning quality assurance by international societies. Results: This survey revealed that practice of quality control is irregular and not satisfactory. The irregularity of the QC practice seems due partly to the lack of trained personnel, equipment, budget, time and hand-on guidelines. Conclusion: The implementation of QC program may cause additional burden to the hospitals, patients and nuclear medicine laboratories. However, the benefit of a good QC program is obvious that the hospitals can provide good quality nuclear medicine imaging studies to the patients. It is important to use least cumbersome QC protocol, to educate the nuclear medicine and hospital administrative personnel concerning QC, and to establish national QC guidelines to help each individual nuclear medicine laboratory.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.19 no.1
• /
• pp.3-11
• /
• 2015

Purpose It is hard to obtain high quality images of knee and T.M joint because of a lot of soft tissues in the knee and T.M joint area. Most conventional system for high resolution scintigraphy was used by 4 mm aperture pinhole collimator. Performance comparison of high-resolution pinhole SPECT for Micro deluxe phantom using conventional system. the aim of this study is to evaluate performance of each aperture according to the diameter size and the usefulness of 24-hour delayed bone scintigraphy. Materials and Methods In this study 6 mm, 8 mm diameter pinhole collimators were mounted on Siemens E.CAM systems. In order to evaluate performance evaluation of each aperture and Micro Deluxe phantom was used for performance comparison of conventional SPECT system, Projection data were obtained with 9 degree increment per 30 second. Transverse images were reconstructed using dedicated OSEM algorithm with recovery of detector blurring. $^{99m}Tc-HDP$ source was used for 24-hour delayed bone scintigraphy. Results The knee joint images obtained with 24-hour delay were improved more than those obtained with 3-hour delay in our study. The 6 mm and 8 mm pinhole collimators FWHM have improved by 28% SNR and Uniformity have improved by 35%, Contrast has improved by 7% in 24-hour delayed knee joint image. While in 24-hour delayed T.M joint image of the 6 mm and 8 mm pinhole collimators FWHM have decreased by 60% SNR has decreased by 20% and Uniformity has decreased by 25%, Contrast has decreased significantly. Conclusion Pinhole collimators with 6 mm and 8 mm diameter could offer a superior performance for 24-hour delayed bone scintigraphy. The use of 24-hour delayed image provides additional benefits for pinhole scintigraphy of knee joint. Therefore, we expect that it is useful for precise diagnosis of knee joint and it is applicable to others joint imaging.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.19 no.1
• /
• pp.62-66
• /
• 2015

Purpose Various database comparison methods(DCM) are used for analyzing functional neuro-imaging. It is possible to statistically evaluate decreased or increased metabolism of abnormal patient's brain by comparing with asymptomatic controls in DCM. And results of DCM are additionally used for easily explaining defect region. The aim of this study was to evaluate usefulness of statistical parametric mapping(SPM) and scenium. Materials and Methods Data of 15 patients($62.02{\pm}15.03year$) underwent $^{18}F-FDG$ brain PET/CT were collected and analyzed. Biograph TruePoint 40 with TrueV, (Siemens) was used as a PET/CT scanner. Scenium(version 4.0) in Syngo.via(version VA30A) and SPM99 were applied for statistical evaluation. Consistency between PET reading and result of DCM were evaluated by 5 nuclear medicine physicians through a questionnaire survey. SUV and SD changes were evaluated by changing iteration, gaussian filter and matrix size in scenium. And average required time for generating result of SPM99 and scenium was compared by 3 medical technologists. Results Consistency from the result of SPM99 and scenium showed 84% and 92.4% compare to PET reading. When iteration 4, FWHM 8 and matrix size 168, SUV and SD were decreased by 0.59%, 8.73%, 4.69%, 20.38% and 0.88%, 8.25% respectively compare to routine parameter(iteration 8, FWHM 2 and matrix size 336) of scenium. Average required time of SPM99 and Scenium took 282 seconds and 116 seconds to generate result. Conclusion Results of SPM99 and Scenium showed high consistency compare to PET reading. Various parameters can be controled by user when using SPM. However, normal database needs to be acquired. And it takes significant amount of time and effort for the first set up. On the other hand, Scenium provides normal database even though modifiable parameters are limited. Therefore, more informations could be provided for brain PET/CT if properly understanding and selecting each DCM.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.19 no.1
• /
• pp.57-61
• /
• 2015

Purpose We considered the correlation of Ejection Fraction (EF) which was analyzed by Multi Gated Blood Pool Scan (MUGA) and Echocardiography (ECHO) for the patients who were classified according to the condition of cardiac function. Materials and Methods We analyzed the patients (female 60) who were diagnosed with breast cancer and were examined by both MUGA and ECHO. The 30 patients (age: $58.27{\pm}13.48$) who were analyzed into less than 50% to 70% of EF were categorized as normal group and the other 30 patients (age: $53.70{\pm}8.45$) who were analyzed into less than 50% of EF were categorized as abnormal group. Statistical analysis with SPSS ver. 18 was applied. Results Each of the value of mean and standard deviation of normal group was $66.43{\pm}5.80$ (MUGA), $60.50{\pm}4.93$ (ECHO). There was a significant difference (p<0.001). Each of the value of mean and standard deviation of abnormal group was $41.93{\pm}7.58$ (MUGA), $41.70{\pm}11.49$ (ECHO). There was no significant difference (p>0.001). In the result, all 30 cases of normal group showed the same reading. 8 out of 30 cases in abnormal group showed inconsistency of the reading. Conclusion We could confirm the correlation of the EF in MUGA and ECHO statistically. There was difference between abnormal groups from the result of reading. If we are aware of the result according to the different cardiac function categorization, MUGA and ECHO can be used as even more accurate interchangeable test.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.24 no.1
• /
• pp.33-38
• /
• 2020

Purpose Vitamin D is essential for maintaining bone health, controling cell proliferation or differentiation, strengthening immune function by controlling calcium metabolism in the body. Vitamin D deficiency can lead to increase the risk of rickets, osteoporosis, cardiovascular disease, diabetes and cancer. Especially, South Korea is one of the highest population proportion of vitamin D deficiency. Accurate determination of levels of 25-OH-VitD or 25-OH-VitD3 in blood serum is required for the diagnosis and treatment of vitamin D deficiency. In this study, radioimmunoassay of 25-OH-VitD and 25-OH-VitD3 was performed and compared to evaluate the effectiveness of Vitamin D radioimmunoassay. Materials and Methods Serum 25-OH-VitD and 25-OH-VitD3 levels were measured using radioimmunoassay. The interrelationship, reproducibility and population distribution rate were evaluated. In addition, the internal quality control was performed at Asan Medical Center from April 2017 to June 2019 and the result of external quality control (Interagency proficiency evaluation) of first and second half of 2018 hosted by the Korean Society of Nuclear Medicine Technology (KSNMT). Both tests were measured by same manufacturer's reagent. Results 25-OH-VitD showed a strong positive correlation on 97 samples, as 25-OH-VitD3 x 0.9 + 0.3 (R>0.9). In repeated measurement, the average Diff(%) value of the reproducibility evaluation of 25-OH-VitD and 25-OH-VitD3 were 7.7% and 7.4%, respectively. Population distribution results showed no statistically significant differences(p>0.05). The resultant value of internal quality control, which measured from April, 2017 to June 2019 in Blood test room of Nuclear Medicine at Asan Medical Center, showed average (CV%) 6.2% and 6.8%, respectively. As a result of the external quality control (interagency proficiency evaluation) Z value obtained under 2.0, as shown below; Conclusion The interrelationship, reproducibility, population distribution rate, internal quality control and external quality control between 25-OH-VitD and 25-OH-VitD3 radioimmunoassay shows superior outcome. Radioimmunoassay, which can be alone measured in the blood as 25-OH-VitD or 25-OH-VitD3, is considered suitable screening tests for the diagnosis of vitamin D deficiency.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.24 no.1
• /
• pp.20-26
• /
• 2020

Purpose It is intended to figure out the errors derived from changes in depth and volume when measuring the Standard source and ^99mTc-pertechnetate by using a Dose calibrator. Then recommend appropriate measurement depth and volume. Materials and Methods As a Dose calibrator, CRC-15βeta and CRC-15R (Capintec, New Jersey, USA) was used, and the measurement sources were ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate was also adopted due to its high frequency of use. The Standard source was respectively measured the changes according to its depth without changing the volume, in a range of 0 cm to 15 cm from the bottom of the ion chamber. ^99mTc-pertechnetate was measured at each depth by changing the volume with 0.1 mL, 0.3 mL, 0.5 mL, 0.7 mL and 0.9 mL Respectively. And the depth range was from 0 cm to 15 cm at the bottom of the ion chamber. Results In the case of Standard source ⁵⁷Co, ¹³³Ba, ¹³⁷Cs and ^99mTc-pertechnetate, there were significant differences according to the measurement depth(p<0.05). ^99mTc-pertechnetate has a negative correlation coefficient according to the depth, and the error of the measured value was negligible at a depth from 0 cm to 7 cm at 0.3 mL and 0.5 mL, and the range of error increased as the volume increased. Conclusion In clinical practice, it is sometimes installed differently than the Standard depth recommended by the equipment company. If it's measured at the recommended depth and volume, it could be thought that unnecessary exposure of the operator and the patient will be reduced, and more accurate radiation exams will be possible in quantitative analysis.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.14 no.7
• /
• pp.586-603
• /
• 2004

One of the subtle problems that make noise control difficult for engineers is “the invisibility of noise or sound.” The visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical or numerical means to visualize the sound field have been attempted and as a result, a great deal of progress has been accomplished, for example in the field of visualization of turbulent noise. However, most of the numerical methods are not quite ready to be applied practically to noise control issues. In the meantime, fast progress has made it possible instrumentally by using multiple microphones and fast signal processing systems, although these systems are not perfect but are useful. The state of the art system is recently available but still has many problematic issues : for example, how we can implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently it is often difficult to determine the origin of the noise and the spatial shape of noise, as highlighted in the title. The first part of this paper introduces a brief history, which is associated with “sound visualization,” from Leonardo da Vinci's famous drawing on vortex street (Fig. 1) to modern acoustic holography and what has been accomplished by a line or surface array. The second part introduces the difficulties and the recent studies. These include de-Dopplerization and do-reverberation methods. The former is essential for visualizing a moving noise source, such as cars or trains. The latter relates to what produces noise in a room or closed space. Another mar issue associated this sound/noise visualization is whether or not Ivecan distinguish mutual dependence of noise in space : for example, we are asked to answer the question, “Can we see two birds singing or one bird with two beaks?"

• Korean Journal of Organic Agriculture
• /
• v.7 no.1
• /
• pp.115-127
• /
• 1998

Under the visual judgement of consumers, to reduce nitrate intake through vegetables, this experimentation analyzed the content of nitrate, in heading leaf vegetables such as chinese cabbage(Brassica campestris L. ssp. perkinensis (Lour.) Rupr), cabbage(Brassica oleracea L. var. capitata) and lettuce(Lactuca sativa L.) by the leaf number. And the result is summarized as follows In the nitrate content change by the leaf number, the nitrate content is increased as it goes by from inner leaf to outer leaf and the nitrate content in leaf midrib is higher than that in leaf blade. In case of chinese cabbage, the nitrate content in the leaf midrib from the most inner leaf to the most outer leaf changed 40-3,177ppm and in the leaf blade it changed 40-2,887ppm. But the nitrate content in the leaf blade of cabbage from the most inner leaf to the most outer leaf changed 89~2,297ppm and in the leaf blade it changed 25~765ppm. In case of lettuce, the nitrate content change of the leaf midrib by the leaf position was 419~4,349ppm, and in the leaf blade it changed 260~2894ppm. It was conclude that the outer leaf of chinese cabbage, cabbage and lettuce should be removed to keep the lower nitrate intake by population before it is consumed.