• The Korean Journal of Nuclear Medicine
• /
• v.28 no.3
• /
• pp.384-390
• /
• 1994

Authors retrospectively compared the 99mTc MDP bone scans and corresponding MR imagings in 20 patients with histologically proven malignancy, Mean interval of the two studies was 16.6 days, Cancer diagnosis Included 8 lung, 2 each of colon, breast, stomach, 1 each of prostate, thyroid, malignant lymphoma and 3 adenocarcinoma of unknown primary site. Of the 105 regions compared, :t6 regions were positive for metastases in bone scans or MR imagings. 30 regions(65.2%) were positive by bone scan and 44 regions(95.7%) by MR imaging. 87 regions(82.9%) were concordantly positive or negative by bone scan and MR imaging, but 18 regions(17.1%) were discordant. In the discordant regions, 16 regions positive in MR imaging were negative in bone scan. The greatest number of discordant findings occured in the cervical region and in the patient with stomach cancer. Our results suggest that the sensitivity of MR Imaging is greater than that of bone scan in detecting spinal metastases. And bone scan is useful screening test of metastasis for evaluating entire skeleton including spine.

• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.5
• /
• pp.386-394
• /
• 2009

Purpose: We aimed to assess the myocardial velocity on gated myocardial perfusion SPECT (gated MPS), to compare myocardial velocity between patients without coronary artery disease (CAD) and CAD patients and to assess the correlation of myocardial velocity and perfusion and wall thickening on CAD group. Materials and Methods: Seventeen patients without CAD (M:F=9:8, mean age $61.8{\pm}11.1$ yrs: group A) and thirty-nine patients with CAD (M:F=18:21, mean age $66.9{\pm}8.1$ yrs : group B) had undergone one-day adenosine stress gated MPS. In twenty segment model, 12 segments (except apical and basal segments) of each patient were included. We obtained systolic and diastolic gate ratio in left ventricular volume curve by eight frames per cardiac cycle on gated MPS. Using the systolic and diastolic gate ratio and R-R time of each patient, we obtained systolic and diastolic time ratio. The myocardial velocity was defined as wall thickening over systolic or diastolic time. Results: We presented normal range of myocardial velocities according segments and territories of coronary artery. The myocardial velocity of group B was significantly lower than group A (p=0.00). There was no significant difference between the myocardial velocity of group B with preserved EF and group A. The stress systolic velocity significantly correlated with regional myocardial perfusion in group B with preserved EF (p=0.00) as well as decreased EF (p=0.01). In group B, stress perfusion of segments which had decreased wall thickening and decreased myocardial velocity was significantly lower than segments which had decreased wall thickening and preserved myocardial velocity (p=0.01). Conclusion: The new functional index of velocity will be used as an useful of gated MPS.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.1
• /
• pp.19-25
• /
• 2014

Purpose: Integrated PET/MRI has been developed recently has become a lot of help to the point oncologic, neological, cardiological nuclear medicine. By using this PET/MRI, a ${\mu}-map$ is created some special MRI sequence which may be divided parts of the body for attenuation correction. However, because an MRI contrast agent is necessary in order to obtain an more MRI information, we will evaluate to see an effect of SUV on PET image that corrected attenuation by MRI with contrast agent. Materials and Methods: As PET/MRI machine, Biograph mMR (Siemens, Germany) was used. For phantom test, 1mCi $^{18}F-FDG$ was injected in cylinderical uniformity phantom, and then acquire PET data about 10 minutes with VIBE-DIXON, UTE MRI sequence image for attenuation correction. T1 weighted contrast media, 4 cc DOTAREM (GUERBET, FRANCE) was injected in a same phatnom, and then PET data, MRI data were acquired by same methodes. Using this PET, non-contrast MRI and contrast MRI, it was reconstructed attenuation correction PET image, in which we evanuated the difference of SUVs. Additionally, for let a high desity of contrast media, 500 cc 2 plastic bottles were used. We injected $^{18}F-FDG$ with 5 cc DOTAREM in first bottle. At second bottle, only $^{18}F-FDG$ was injected. and then we evaluated a SUVs reconstructed by same methods. For clinical patient study, rectal caner-pancreas cancer patients were selected. we evaluated SUVs of PET image corrected attenuastion by contrast weighted MRI and non-contrast MRI. Results: For a phantom study, although VIBE DIXON MRI signal with contrast media is 433% higher than non-contrast media MRI, the signals intensity of ${\mu}-map$, attenuation corrected PET are same together. In case of high contrast media density, image distortion is appeared on ${\mu}-map$ and PET images. For clinical a patient study, VIBE DIXON MRI signal on lesion portion is increased in 495% by using DOTAREM. But there are no significant differences at ${\mu}-map$, non AC PET, AC-PET image whether using contrast media or not. In case of whole body PET/MRI study, %diff between contras and non contrast MRAC at lung, liver, renal cortex, femoral head, myocardium, bladder, muscle are -4.32%, -2.48%, -8.05%, -3.14%, 2.30%, 1.53%, 6.49% at each other. Conclusion: In integrated PET/MRI, a segmentation ${\mu}-map$ method is used for correcting attenuation of PET signal. although MRI signal for attenuation correciton change by using contrast media, ${\mu}-map$ will not change, and then MRAC PET signal will not change too. Therefore, MRI contrast media dose not affect for attenuation correction PET. As well, not only When we make a flow of PET/MRI protocol, order of PET and MRI sequence dose not matter, but It's possible to compare PET images before and after contrast agent injection.

• Journal of Radiation Protection and Research
• /
• v.35 no.1
• /
• pp.34-42
• /
• 2010

With the expanded use of radiation in modern medical practices, the most important issue in regards to efforts to reduce individual exposure dose is quality assurance. Therefore in order to study the present condition of quality assurance, the Gwangju Metropolitan City area was divided into five districts each containing ten hospitals. Four experiments were conducted: a reproducibility experiment for kVp, mA, and examination time (sec) intensity of illumination; half-value layer (HVL) measurement; and beam perpendicularity test matching experiment. The tube voltage reproducibility experiment for all fifty hospitals resulted in a 95.33% passing rate and mA and examination time both resulted in a 77.0% passing rate. The passing rate for intensity of illumination was 86.0% and 52.0% for HVL, which was the lowest passing rate of all four factors. For the beam perpendicularity test matching experiment, generally the central flux is matched to within $1.5^{\circ}$. Of all fifty hospitals 30.0% were beyond $3^{\circ}$. The results of the survey showed that 58% responded that they knew about quality assurance cycle. All fifty respondents stated that they have not received any training in regards to quality assurance at their current place of employment. Although quality assurance is making relative progress, the most urgent issue is awareness of the importance of quality assurance. Therefore, the implementation of professional training focusing on safety management and accurate quality assurance of radiation will reduce the exposure to radiation for radiologists and patients and higher quality imaging using less dosage will also be possible.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2002.06a
• /
• pp.148-155
• /
• 2002

Multithreaded models improve the efficiency of parallel systems by combining inner parallelism, asynchronous data availability and the locality of von Neumann model. This model executes thread code which is generated by compiler and of which quality is given by the method of generation. But multithreaded models have the demerit that execution model is restricted to a specific platform. On the contrary, Java has the platform independency, so if we can translate from threads code to Java bytecode, we can use the advantages of multithreaded models in many platforms. Java executes Java bytecode which is intermediate language format for Java virtual machine. Java bytecode plays a role of an intermediate language in translator and Java virtual machine work as back-end in translator. But, Java bytecode which is translated from multithreaded models have the demerit that it is not secure. This paper, multhithread code whose feature of platform independent can execute in java virtual machine. We design and implement translator which translate from thread code of multithreaded code to Java bytecode and which check secure problems from Java bytecode.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.2
• /
• pp.111-119
• /
• 1999

Purpose: As mesial temporal lobe epilepsy (TLE) shows hypometabolism of medial and lateral temporal lobe, we investigated whether symmetric uptake of F-18-FDG in medial temporal lobes can differentiate mesial from lateral TLE. Materials and Methods: In 113 patients (83 mesial TLE, 30 lateral TLE) who underwent anterior temporal lobectomy and/or corticectomy with good surgical outcome, we performed F-18-FDG PET and compared F-18-FDG uptake of medial and lateral temporal lobes. All the patients with mesial TLE had hippocampal sclerosis except one congenital abnormal hippocampus. Patients with lateral TLE revealed cerebromalacia, microdysgenesis, arteriovenous malformation, old contusion, and cortical dysplasia. Results: Sensitivity of F-18-FDG PET and MR for mesial TLE was 84% (70/83) and 73% (61/83), respectively. Sensitivity of F-18-FDG PET and MR for lateral TLE was 90% (27/30) and 66% (20/30), respectively. Twelve patients were normal on F-18-FDG PET. 101 patients had hypometabotism of lateral temporal lobe. Among 88 patients who showed hypometabolism of medial temporal lobe as well as lateral temporal lobe, 70 were mesial TLE patients and 18 were lateral TLE on pathologic examination. Positive predictive value of medial temporal hypometabolism for mesial TLE was 80%. Among 13 patients who showed hypometabolism of only lateral temporal lobe, 4 were mesial TLE and 9 were lateral TLE. Positive predictive value of hypometabolism of lateral temporal lobe for the diagnosis of lateral TLE was 69% (9/13). Normal MR findings stood against medial TLE, whose negative predictive value was 66%. Conclusion: Lateral temporal lobe epilepsy should be suspected when there is decreased F-18-FDG uptake in lateral temporal lobe with normal uptake in medial temporal lobe.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.5
• /
• pp.410-417
• /
• 2000

Purpose: Idoxifene is currently entering phase II clinical trials for the treatment of advanced breast cancer. The radiolabeled idoxifene using $[^{123}I]$ provides an opportunity for clinical pharmacology with single photon emission computed tomography (SPECT). The purpose of this study was to prepare radiolabeled idoxifene using $[^{123}I]$ and to determine its cell uptake of breast cancer cell line. Materials and Methods: With a view to evaluating new anticancer drugs, we are investigating the novel antiestrogen pyrrolidino-4-iodotamoxifen (idoxifene). $[^{123}I]$Idoxifene has been prepared in no-carrier-added form using a tributyl stannylated precursor which has been synthesized by means of (2-chloroethoxy)benzene with (${\pm}$)-2-phenylbutanoic acid on the basis of previously reported standard methods. The biodistribution and dynamic behavior of the compound were investigated using the comparative breast cancer cell line, MCF-7 (estrogen receptor-positive) and MDA-MB-468 (non-estrogen receptor). Results and Conclusion: Acylation of (2-chloroethoxy)benzene with (${\pm}$)-2-phenylbutanoic acid gave the versatile ketone (81%) which reacted with 1,4-diiodobenzene to give triphenylethylene as a mixture of E and Z geometric isomers, which were separated by the recrystallization in ethanol. The E-isomer was treated with pyrrolidine to give idoxifene (67%). In order to incorporate radioactive iodine into the 4-position, the 4-stannylated precursor was prepared (30%). The yield of radioiodination was 90-92% with a high radiochemical purity greater than 98%. The ratio of tumor uptake of the breast cancer cell line between MCF-7 and MDA-MB-468 was about 1.7.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.2
• /
• pp.131-142
• /
• 1999

Purpose: Either gated myocardial perfusion SPECT or attenuation corrected SPECT can be used to improve specificity in the diagnosis of coronary artery disease. We investigated in this study whether gating or attenuation correction improved diagnostic performance of rest/stress perfusion SPECT in patients having intermediate pre-test likelihood of coronary artery disease. Materials and Methods: Sixty-eight patients underwent rest attenuation-corrected T1-20l/dipyridamole stress gated attenuation-corrected Tc-99m -MIBI SPECT using an ADAC vertex camera (M:F=29:39, aged $59{\pm}12$ years, coronary artery stenosis ${\geq}70%$, one vessel: 13, two vessel: 18, three vessel: 8, normal: 29). Using a five-point scale, three physicians graded the post-test likelihood of coronary artery disease for each arterial territory (1:normal, 2: possibly normal, 3:equivocal, 4. possibly abnormal, 5: abnormal). Sensitivity, specificity and area under receiver-operating-characteristic curves were compared for each operator between three methods : (A) non-attenuation-corrected SPECT; (B) gated SPECT added to (A): and (C) attenuation-corrected SPECT added to (B). Results: When grade 3 was used as the criteria for coronary artery disease, no differences in sensitivity and specificity were found between the three methods for each operator. Areas under receiver-operating-characteristic curves for diagnosis of coronary artery disease revealed no differences between each modality (p>0.05). Conclusion: In patients at intermediate risk of coronary artery disease, gated SPECT and attenuation- corrected SPECT did not improve diagnostic performance.

• The Korean Journal of Nuclear Medicine
• /
• v.33 no.2
• /
• pp.143-151
• /
• 1999

Purpose: Dermatolymphangioadenitis (DLA) is a common and serious complication of lymphedema which deteriorates lymphatic function. The purpose of this study was to assess the risk of DLA by lymphos-cintigraphy in patients with lower extremity lymphedema. Materials and Methods: The subjects were 59 edematous lower extremities of 50 patients without previous episode of DLA and 12 lower extremities of 6 controls. Whole body images were acquired 1 min and 2 hr after subcutaneous injection of 37 MBq of Tc-99m-antimony sulfide colloid into interdigital spaces of both feet before therapy for lymphedema. The lymphosintigraphic and clinical variables were compared between groups with or without occurrence of DLA during clinical follow up. Results: There were 20 episodes of DLA in 12 extremities during clinical follow-up (19 :6 months). On univariate analysis, there were significant differences in ilioinguinal lymph node uptake, uptake pattern of main lymphatic vessel, clinical stage and therapy compliance between the two groups. After multivariate analysis, only the uptake pattern of main lymphatic vessel and therapy compliance fore confirmed to be independent variables. In other words, non-visualized main lymphatic vessel and poor compliance to therapy were more frequent in extremities with subsequent occurrence of DLA. Conclusion: Lymphoscintigraphy can be used to predict the risk of DLA and may thus be helpful for determining the initial therapeutic plan in patients with lower extremity lymphedema.

• Journal of Veterinary Clinics
• /
• v.31 no.6
• /
• pp.495-501
• /
• 2014

The objective of this study was to evaluate the differences and reproducibility of Hounsfield unit (HU) value and volume measurements on different computed tomography (CT) scanner types and different collimations by using a gelatin phantom. The phantom consisting of five synthetic simulated calculus spanning diameters from 3.0 mm to 12.0 mm with 100 HU was scanned using a two-channel multi-detector row CT (MDCT) scanner, a four-channel MDCT scanner, and two 64-channel MDCT scanners. For all different scanner types, the thinnest possible collimation and the second thinnest collimation was used. The HU values and volumes of the synthetic simulated calculus were independently measured three times with minimum intervals of 2 weeks and by three experienced veterinary radiologists. ANOVA and Scheff$\acute{e}$ test for the multiple comparison were performed for statistical comparison of the HU values and volumes of the synthetic simulated calculus according to different CT scanner types and different collimations. The reproducibility of the HU value and volume measurements was determined by calculating Cohen's k. The reproducibility of HU value and volume measurements was very good. HU value varied between different CT scanner types, among different beam collimations. However, there was not statistically significant difference. The percent error (PE) decreased as the collimation thickness decreased, but the decrease was statistically insignificant. In addition, no statistically significant difference in the PEs of the different CT scanner types was found. It can be concluded that the CT scanner type insignificantly affects HU value and the volumetric measurement, but that a thinner collimation tends to be more useful for accurate volumetric measurement.