• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.77-78
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• 2008

A 71-year-old woman was assigned to our department for Tc-99m myocardial perfusion SPECT(MPS) and coronary CT angiography. She admitted for substernal pain, via the ER, 2 days ago. The heart was scanned after intravenous injection of 925 MBq of $^{99m}Tc$-sestamibi adenosine-induced stress SPECT using dual head gamma camera (Hawkeye, GE healthcare. USA). The MPS shows decreased tracer uptake in the apical & mid area of anterior & lateral wall and mid & basal inferior wall. Coronary CT angiograph was obtained using Discovery VCT (GE healthcare). 3D angiography portrayed significant stenosis of ramus intermedius(RI) and posterolateral branch of right coronary artery(PLB) with fibrocalcified plaque. Two images were fused using Cardiac IQ fusion softwear package (Advantage workstation 4.4, GE healthcare) The fusion images explain the perfusion defect of anterior, lateral and inferior wall is due to stenosis of the RI and PLB. And 3 days later, coronary angiography was done and revealed the marked stenosis of RI and PLB. Then balloon angioplasty and stent was instituted in RI. Cardiac SPECT/CT fusion imaging provides additional information about hemodynamic relevance and facilitates lesion interpretation by allowing exact allocation of perfusion defects to its subtending coronary artery.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.2
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• pp.15-24
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• 2021

Purpose SPECT/CT was noted for its excellent correction method and qualitative functions based on fusion images in the early stages of dissemination, and interest in and utilization of quantitative functions has been increasing with the recent introduction of companion diagnostic therapy(Theranostics). Unlike PET/CT, various conditions like the type of collimator and detector rotation are a challenging factor for image acquisition and reconstruction methods at absolute quantification of SPECT/CT. Therefore, in this study, We want to find out the effect on the radioactivity concentration estimate by the increase or decrease of the total acquisition time according to the number of projections and the acquisition time per projection among SPECT/CT imaging conditions. Materials and Methods After filling the 9,293 ml cylindrical phantom with sterile water and diluting 99mTc 91.76 MBq, the standard image was taken with a total acquisition time of 600 sec (10 sec/frame × 120 frames, matrix size 128 × 128) and also volume sensitivity and the calibration factor was verified. Based on the standard image, the comparative images were obtained by increasing or decreasing the total acquisition time. namely 60 (-90%), 150 (-75%), 300 (-50%), 450 (-25%), 900 (+50%), and 1200 (+100%) sec. For each image detail, the acquisition time(sec/frame) per projection was set to 1.0, 2.5, 5.0, 7.5, 15.0 and 20.0 sec (fixed number of projections: 120 frame) and the number of projection images was set to 12, 30, 60, 90, 180 and 240 frames(fixed time per projection:10 sec). Based on the coefficients measured through the volume of interest in each acquired image, the percentage of variation about the contrast to noise ratio (CNR) was determined as a qualitative assessment, and the quantitative assessment was conducted through the percentage of variation of the radioactivity concentration estimate. At this time, the relationship between the radioactivity concentration estimate (cps/ml) and the actual radioactivity concentration (Bq/ml) was compared and analyzed using the recovery coefficient (RC_Recovery Coefficients) as an indicator. Results The results [CNR, radioactivity Concentration, RC] by the change in the number of projections for each increase or decrease rate (-90%, -75%, -50%, -25%, +50%, +100%) of total acquisition time are as follows. [-89.5%, +3.90%, 1.04] at -90%, [-77.9%, +2.71%, 1.03] at -75%, [-55.6%, +1.85%, 1.02] at -50%, [-33.6%, +1.37%, 1.01] at -25%, [-33.7%, +0.71%, 1.01] at +50%, [+93.2%, +0.32%, 1.00] at +100%. and also The results [CNR, radioactivity Concentration, RC] by the acquisition time change for each increase or decrease rate (-90%, -75%, -50%, -25%, +50%, +100%) of total acquisition time are as follows. [-89.3%, -3.55%, 0.96] at - 90%, [-73.4%, -0.17%, 1.00] at -75%, [-49.6%, -0.34%, 1.00] at -50%, [-24.9%, 0.03%, 1.00] at -25%, [+49.3%, -0.04%, 1.00] at +50%, [+99.0%, +0.11%, 1.00] at +100%. Conclusion In SPECT/CT, the total coefficient obtained according to the increase or decrease of the total acquisition time and the resulting image quality (CNR) showed a pattern that changed proportionally. On the other hand, quantitative evaluations through absolute quantification showed a change of less than 5% (-3.55 to +3.90%) under all experimental conditions, maintaining quantitative accuracy (RC 0.96 to 1.04). Considering the reduction of the total acquisition time rather than the increasing of the image acquiring time, The reduction in total acquisition time is applicable to quantitative analysis without significant loss and is judged to be clinically effective. This study shows that when increasing or decreasing of total acquisition time, changes in acquisition time per projection have fewer fluctuations that occur in qualitative and quantitative condition changes than the change in the number of projections under the same scanning time conditions.

• Imaging Science in Dentistry
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• v.47 no.4
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• pp.227-231
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• 2017

Purpose: Sialolithiasis is one of the most prevalent large obstructive disorders of the submandibular glands. The aim of this study was to investigate submandibular sialolithiasis with computed tomography (CT) and scintigraphy, with a particular focus on the relationship between CT values of the submandibular glands and their excretion rate. Materials and Methods: Fifteen patients with submandibular sialolithiasis who underwent CT and salivary gland scintigraphy were included in this study. The relationship between the CT values of submandibular glands with and without sialoliths and salivary gland excretion measured using salivary gland scintigraphy was statistically analyzed. Dynamic images were recorded on the computer at 1 frame per 20 seconds. The salivary gland excretion fraction was defined as A (before stimulation test [counts/frame]) / B (after stimulation test [counts/frame]) using time-activity curves. Results: The CT values in the submandibular glands with and without sialoliths was $9.9{\pm}44.9$ Hounsfield units(HU) and $34.2{\pm}21.8HU$, respectively (P=.233). Regarding the salivary gland excretion fraction using scintigraphy, the A/B value in the submandibular glands with sialoliths ($1.09{\pm}0.23$) was significantly lower than in the submandibular glands without sialoliths($1.99{\pm}0.57$, P=.000). Conclusion: Assessments of the CT values and the salivary gland excretion fraction using scintigraphy in the submandibular glands seem to be useful tools evaluating submandibular sialolithiasis.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.21-26
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• 1999

To investigate the combined effect of radiation and pesticide on Tradescantia somatic cell mutations, potted plants of Tradescantia 4430 on which parathion had been sprayed evenly 24 hours before irradiation. Radiation doses were 0.3, 0.5, 1.0 and 2.0 Gy of gamma-ray. The plants irradiated only with the gamma-ray radiation were used as control groups (CT). Pink mutation frequency increased linearly proportional to the radiation dose and the peak interval of elevated mutation frequencies appeared during 7 ~ 11 days after irradiation in both CT and Pa +${\gamma}$ groups. The slope of dose -response curve in CT was 5.99 ($r^2$= 0.988), while it was 3.43 (r$x^-2$=0.981) in Pa+${\gamma}$. It seemed that parathion pretreatment had a protective effect against radiation-induced cell damages since it decreased the slope value by 43%. It is suggested that an adaptive response or radiomodification could be induced in irradiated stamen hair cells by parathion pretreatment.

• Journal of Environmental Science International
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• v.12 no.2
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• pp.201-205
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• 2003

The dechlorination of chlorinated methanes by iron powder and palladium coated iron (Pd/Fe) was studied in batch experiments. Iron powder dechlorinated carbon tetrachloride (CT) with a half-life of 4 days. Three chloromethane was found as major product and less chlorinated daughters. Mass balance found was to be about 93-99%. Pd/Fe showed very enhanced reactivity for CT in comparing with plain iron. The major dechlorination products of CT were also less chlorinated methanes with Pd/Fe. Pd/Fe also degrade the produced less chlorinated compounds. Sequential reactions were occurred on Pd/Fe. As the Pd/Fe content increased, the reaction rate was increased linearly.

• The Korean Journal of Nuclear Medicine
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• v.39 no.5
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• pp.269-277
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• 2005

Purpose: This study evaluated the diagnostic value of $^{18}F-FDG$ PET/CT in detecting cervical lymph node metastases in head and neck cancer patients. Materials & Methods: The patients were divided into two groups, 46 patients underwent PET/CT scan for initial staging before surgery, and 20 patients for restaging of recurrence after primary treatment. Increased FDG uptakes in cervical lymph nodes were evaluated retrospectively and correlated with the histopathologic results. Results: In the initial staging group, 21 lymph nodes were detected by PET/CT in 15 patients. 20 lymph nodes were confirmed as metastases with a mean peak SUV of 5.84, and the remaining one lymph node was an inflammatory lesion, with a peak SUV of 2.75. Seven metastatic lymph nodes were reported only by histopatholoay. The sensitivity, specificity, positive predictive value and negative predictive value were 74.0%, 99.6%, 95.2% and 97.3%, respectively. In the recurrence group, 11 lymph nodes were detected in 9 patients, and 8 nodes were true positive, with a mean peak SUV of 5.65. The other three were inflammatous lymph nodes, and the peak SUVs were 2.16, 2.94 and 3.53. One false negative lymph node was reported. The sensitivity, specificity, positive predictive value and negative predictive value were 88.8%, 97.7%, 72.7% and 92.9%, respectively. Conclusions: FDG-PET/CT shows higher positive predictive value in the initial staging group, and better sensitivity in the recurrence group. Therefore PET/CT could be useful for both initial staging and restaging of recurrent cervical lymph node metastases.

• The Korean Journal of Nuclear Medicine
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• v.35 no.4
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• pp.268-273
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• 2001

Thymoma is the most common primary tumor of anterior mediastinum, accounting for 20% to 30% of all mediastinal tumors. The recurrence rate after total resection of the thymoma ranges 8% to 18%. We reported one patient of recurrent malignant thymoma imaged with Tc-99m MIBI, Tc-99m Tetrofosmin and Tc-99m (V) DMSA. Early and delayed Tc-99m MIBI and Tc-99m Tetrofosmin scintigraphies showed an increased uptake in the mediastinal area. Also, Tc-99m (V) DMSA scintigraphy revealed an increased uptake tn the corresponding area. Coronal SPECT images of Tc-99m MIBI, Tc-99m Tetrofosmin and Tc-99m (V) DMSA revealed increased uptake of each radiopharmaceutical in the tumor lesion corresponding to the mediastinal lesion on the chest CT. However, the normal blood pool activities of the heart and great vessels of Tc-99m (V) DMSA obscured the recurrent malignant thymoma. Although Tc-99m (V) DMSA is a useful tumor seeking agent, we recommend Tc-99m MIBI and Tc-99m Tetrofosmin SPECT rather than Tc-99m (V) DMSA to detect primary and recurrent malignant thymoma.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.190-191
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• 2006

A 44-year-old man with a past medical history of splenectomy came to hospital because of epigastric pain. Abdominopelvic computed tomography(CT) showed a soft tissue mass and multifocal variable-sized nodules as well as findings suggestive of cholecystitis. Subsequently, he underwent Tc-99m-labeled heat-denatured red blood cell(RBC) scintigraphy to evaluate the mass and nodules. The scintigraphy confirmed multifocal peritoneal splenosis in the abdominopelvic cavity.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.375-379
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• 2010

Purpose: The nasal bone is the most frequently fractured facial bone. Discordance between the CT reading by the radiologist and the diagnosis by the plastic surgeon is not uncommon. This study examined the discordance and proposes a method for reducing the rate of discordance. Methods: The CT readings by the radiologist were compared with the diagnosis by the plastic surgeon in 716 patients with a clinically suspected nasal bone fracture. The CT reading was classified as the following: a nasal bone fracture, suspicious nasal bone fracture, old nasal bone fracture, no nasal bone fracture. The sensitivity, specificity and positive predictive value of the CT reading were calculated. Results: A nasal bone fracture was diagnosed in 646 patients by the plastic surgeon and confirmed intraoperatively. The reading of a "nasal bone fracture", "suspicious nasal bone fracture", "old nasal bone fracture" and "no nasal bone fracture" was 85.8%, 4.6%, 0.6% and 9.1% respectively. The sensitivity and specificity of the CT reading were 95.0% and 92.9%, respectively. The positive predictive value of the CT reading was 99.3%. The reading of "nasal bone fracture" that was not a nasal bone fracture clinically was 17.1% (12 of 70), and the reading of "no nasal bone fracture" or "old nasal bone fracture" that was found to be a nasal bone fracture clinically was 3.3% (21 of 646). The discordance rate between the CT reading by the radiologist and the diagnosis by the plastic surgeon was 4.6%. Conclusions: To reduce the discordance rate, we propose to hold a meeting with the plastic surgery-radiology staff to communicate the information regarding a suspicious or old nasal bone fracture.

• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.109-117
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• 2021

Purpose: To investigate the reliability of CT and MRI for quantitative and qualitative analyses of lumbar paraspinal muscle fatty infiltration (PSFI) and correlation of PSFI with intervertebral disc pathology. Materials and Methods: Lumbar spine CT and MRI of 36 subjects were reviewed retrospectively. Two observers independently outlined lumbar paraspinal muscles at each mid-intervertebral disc level. Paraspinal muscles on CT and MRI were graded according to the Goutallier grading system (GGS). The area, mean value, and standard deviation (SD) of the Hounsfield unit (HU) were obtained. Intervertebral discs were assessed on axial image of T2WI at each level. Correlations between qualitative and quantitative data and intervertebral disc pathology, age, and sex were evaluated. Results: Inter- and intra-observer agreements for results of GGS on MRI were substantial (κ = 0.79) and moderate (κ = 0.59), respectively. Inter- and intra-observer agreements for results of GGS on CT were almost perfect (κ = 0.88) and substantial (κ = 0.66), respectively. Quantitative measurements of HU showed almost perfect inter- and intra-observer reliabilities (κ = 0.82 and κ = 0.99, respectively). There were statistically significant correlations between intervertebral disc pathology and PSFI at L1-2, L2-3, and L4-5 levels on MRI and at L1-2 and L3-4 levels on CT. Age showed significant correlation with results of GGS at all levels on CT and MRI. Conclusion: This study showed that GGS results and HU measurements could be useful for evaluating PSFI because they showed correlations with intervertebral disc pathology results at certain levels.