• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.179-185
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• 2007

Backgroud : Urinary tract infection (UTI) is common in children. The available gold standard methods for diagnosis, Tc-99m dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) are invasive and expensive. This study was performed to assess the role of power Doppler ultrasound (PDU) for diagnosis of acute pyelonephritis (APN). Materials and Methods : A prospective study was conducted in 25 children with aged 2 weeks to 5 years who were hospitalized with the first episode of febrile UTI suggesting acute pyelonephritis. All children were examined in the first 3-5 days of admission by PDU and Tc-99m DMSA scan. The comparison between PDU and DMSA scan was performed on the basis of patients. Results : The sensitivity and specificity of PDU for the detection of affected kidneys were 38.1% and 50.0%, and the positive predictive value and negative predictive value were 61.9% and 50.0%, respectively. Vesicoureteral refluxes (VUR) were identified in 11 patients (44.4%) and 18 kidneys (36%). The PDU and DMSA scan showed a matching perfusion defect in 23.8% and 50.0% respectively. Conclusion : These data indicate the PDU has a relatively low sensitivity and specificity for differentiating APN from lower UTI but may be a complement tool to DMSA scan for the prediction of VUR in infants and children.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.124-129
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• 2018

This study was conducted to investigate the penetration dose and shielding rates of tungsten shields used in apron material by changing the type of source used in the nuclear medicine department, thickness of shielding material and distance between the source and detector. For the experiment, the source, shield, and detector were arranged in a straight line and measured with an inspector at a height of 100 cm. The highest shielding effect of tungsten was measured for $^{201}Tl$, while $^{123}I$ showed a higher shielding effect than $^{99m}Tc$. For the sources used in the experiment, the penetration dose decreased with distance and the shielding rate was measured with thicker thickness. However, the shielding rate of $^{13}1I$ and $^{18}F$ sources was found to be lower than when there was no shielding at 0.25 mmPb shield. Therefore, even if the radiation shielding effect of tungsten is high, considering the characteristics according to the type of source and the thickness of the shielding material, it may be helpful to reduce the exposure.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.1
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• pp.62-73
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• 2015

We developed an evans blue-indocyanine green-$^{99m}Tc$-human serum albumin conjugate for sentinel lymph node mapping and we describe its unique potential usage for clinical implications. This conjugate has combined the strengths of visible blue dye, near-infrared fluorescence and radioisotope into one single conjugate without any additional weakness/disadvantage. All the components of evans blue-indocyanine green-$^{99m}Tc$-human serum albumin are safe and of low cost, and they have already been clinically used. This conjugate was stable in the serum, it showed a long retention time in the lymphatic system and the lymph nodes showed a much higher signal-to-noise ratio after the conjugate was injected intradermally into the paw of mice. Both the single-photon emission computed tomography and near-infrared fluorescent images of the mice were successfully obtained at the same time as the excised sentinel lymph nodes showed blue color. The visual color, near-infrared fluorescence and gamma ray from this agent could be complementary for each other in all the steps of sentinel lymph node sampling: exploring and planning sentinel lymph node before excision with visualization of the exact sentinel lymph node location during an operation. Therefore, the triple modal agent will possibly be very ideal for sentinel lymph node mapping because of the high signal-to-noise ratio for non-invasive imaging and its complementary multimodal nature, easy preparation and safety. It is promising for clinical applications and it may have great advantages over the traditional single modal methods.

• The Korean Journal of Nuclear Medicine
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• v.25 no.1
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• pp.61-67
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• 1991

The usefulness of $^{99m}Tc-labeled$ RBC single photon emission CT (SPECT) scanning in the diagnosis of hepatic heminagiomas was evaluated in 22 patients with various focal hepatic lesions including 15 cases of hemangiomas, 3 cases each of hepatomas and metastasis and 1 case of abscess. The diagnoses were based on ultrasonography and/or CT scanning, clinical stability of lesion for at least 6 months or surgical exploration. Seven cases of 15 hemangiomas were detected by delayed planar RBC scanning, whereas 4 cases were detected by delayed RBC-SPECT scanning. The smallest hemangioma shown by delayed RBC-SPECT scanning was 1.0 cm in diameter. compared with 2.2 cm by planar RBC scanning. One small hemangioma (2.0 cm) located adjacent to the heart was not found by either method. The sensitivities in detecting the hemangioma according to the site by planar imaging were 16.6% $(1.0\sim1.9cm)$, 66.7% $(2.0\sim2.9cm)$ and 83.3% (more than 3.0 cm) and by SPECT were 50.0%, 66.7% and 100%, respectively. Seven cases of non-hemangiomatous lesions did not show any significant increase in activity in the delayed blood pool images. It is concluded that $^{99m}Tc-RBC$ blood-pool SPECT scanning is clearly more sensitive in detecting small hemangioma than planar scanning and is, therefore, a choice of method for the detection of hepatic hemangioma.

• The Korean Journal of Nuclear Medicine
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• v.25 no.1
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• pp.87-94
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• 1991

To evaluate the diagnostic usefulness of quantitative sacroiliac joint scintigraphy and its clinical significance in the ankylosing spondylitis, we measured SIS ratio (Sacroiliac Joint/Sacrum Uptake ratio) by region of interest method in 52 patients with ankylosing spondylitis. As compared with radiological grade, SIS ratio was significantly elevated in the early stage of ankylosing spondylitis and returned to normal range in the late stage. Scintigraphic finding of focal uptakes of radiotracer at multiple spinal apophyseal joints was characteristic and proximal large joints were more involved than distal joints. The incidence and extent of the arthropathy revealed by scnitigraphy exceeded that which was clinically evident, and scintigraphy was more sensitive to detect symptomatic lesion than radiography. Therefore, it is suggested that bone scan is useful for the early diagnosis and the assessment of clinical activity of involved joints of ankylosing spondylitis.

• The Korean Journal of Nuclear Medicine
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• v.26 no.2
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• pp.333-337
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• 1992

In order to establish the clinical significance of pubic bone uptake of radionuclide on $^{99m}Tc-MDP$ bone scintigraphs, we analyzed uptake patterns of normal adult pubic bone in 300 randomly sampled subjects. Bone scintigraphy was performed in each patient for the reasons other than pubic or pelvic problems. One-hundred-fifty-four were men and 146 women. The age ranged from 8 to 78 years. The pubic uptake was graded arbitrarily into 4 grades by comparing the pubic uptake density with that of L5 vertebra. Thus, grade I was defined as the L5 density greater than the pubic density, grade II as the L5 density equals to the pubic density, grade III as the L5 density less than the pubic cdensity, and grade IV as the L5 density much less than the pubic density. Statistical analysis revealed negative trend in the pubic uptake from grade IV to grade I with age. There was no sexual difference in the pubic uptake. The women in the 3rd and 4th decades disclosed higher pubic uptake (grades III, IV) probably due to pregnancy and labor.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.47-55
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• 1996

Progressive supranuclear palsy (PSP) is a parkinson-plus syndrome characterized clinically by supranuclear ephthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormality and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using $^{99m}Tc$-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.257-261
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• 2004

A coded-aperture gamma camera was developed to increase the sensitivity of a pin hole camera made with a pixellated CsI(Tl) scintillator and a position-sensitive photomultiplier tube. The modified round-hole uniformly redundant array of pixel size $13{\times}11$ was chosen as a coded mask considering the detector spatial resolution. The performance of the coded-aperture camera was compared with the pin hole camera using various forms of Tc-99m source to see the improvement of signal-to-noise ratio or the improvement of the sensitivity. The image quality is much improved despite of a slight degradation of the spatial resolution. Though the camera and the test were made for low energy case, but the concept of the coded-aperture gamma camera could be effectively used for the radioactive environmental monitoring and other applications.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.287-293
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• 1995

Anterior temporal lobectomy has become a widely used resective surgery in patients with medically intractable temporal lobe epilepsies. Prerequisites of this resection include the accurate localization of the epileptogenic focus and the determination that the proposed resection would not result in unacceptable postoperative memory or language deficits. The purpose of this study was to evaluate the performance of ictal SPECT compared to MRI findings for localization of epiletogenic foci in this group of patients. 11 patients who had been anterior temporal lobectomy were evaluated with ictal $^{99m}Tc$-HMPAO SPECT and MRI. MRI showed 8/11(73%) concordant lesion to the side of surgery and ictal SPECT also showed 8/11(73%) concordant hyperperfusion. In 3 cases with incorrect or nonlocalizing findings of MRI, ictal SPECT showed concordant hyperperfusion. In 2 cases confirmed by pre-resectional invasive EEG, MRI showed bilateral and contralateral lesion but ictal SPECT showed concordant hyperperfusion. 3 delayed injection of ictal SPECT showed discordant hyperperfusion. Thus, ictal SPECT was a useful method for localizing epileptogenic foci in temporal lobe epilepsis and appeared complementay to MRI.

• Progress in Medical Physics
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• v.13 no.4
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• pp.229-233
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• 2002

We have tested a combined CT/SPECT system with a single CZT detector for x-ray and gamma-ray medical imaging. The size of detector is 10$\times$10$\times$5 ㎣, and the anodes are pixellated as a 4$\times$4 array with a pixel dimension of $1.5\times$1.5 $\textrm{mm}^2$. The cathode was coated with a continuous Au-plated. We have characterized the system performance by scanning a radiographic resolution phantom and the Hoffman Brain phantom. Pulse counting electronics with very short shaping time (50 ㎱) are used to satisfy high photon rates in x-ray imaging, and response linearity up to 3$\times$10$^{5}$ counts per second per detector element is achieved. Energy resolution of 10.4% and 5.3% FWHM at Tc-99m 140 keV peak are obtained for the 50 ㎱ and 2 $mutextrm{s}$ shaping times, respectively. The spatial resolutions of CT and SPECT are about 1mm and 9mm, respectively. Photopeak efficiency of detector systems are 41.0% for 50㎱ and 72.5% for 2 $mutextrm{s}$ shaping time.