• Nuclear Medicine and Molecular Imaging
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• v.40 no.1
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• pp.28-32
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• 2006

Purpose: Conventional chest X-ray and pulmonary function test cannot sensitively detect inhalation injury. Bronchoscopy is known to be the gold standard but it is invasive method. We evaluated whether lung inhalation/perfusion scans can sensitively detect inhalation injury of fire victims. Materials and Methods: Nineteen patients (male 9, female 10, mean age 31.6 yr) of fire victims were enrolled in this study. Inhalation lung scan was performed 2 days later after inhalation injury with $^{99m}Tc$-technegas. Perfusion lung scan was performed 4 days later with $^{99m}Tc$- MAA (macroaggregated albumin). Follow up lung scans were performed 16 and 18 days later for each. Chest X-ray was performed in all patients and bronchoscopy was performed in 17 of 19 patients at the same period. Pulmonary function test was performed in 9 patients. Results: Four of 19 patients showed inhalation and perfusion defects and one showed inhalation defect but, normal perfusion scan findings. These five patients with abnormal scan findings showed abnormal bronchoscopic findings and severe respiratory symptoms. On chest X-ray, 2 of them had pulmonary tuberculosis and one of them showed pulmonary congestion. FEV1 /FVC was abnormal in 3 patients. On the follow up scan, all patients with abnormal initial scan findings showed improved findings and they had improved clinical state. Conclusion: Inhalation/perfusion lung scans can detect inhalation burn injury noninvasively in early stage and may be useful in therapeutic decision making and follow up of patients.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.201-208
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• 2007

Purpose: We investigated whether the diagnostic performance of SPECT scintimammography (SMM) can be improved by adding computer-aided diagnosis (CAD) of ultrasonography (US). Materials and methods: We reviewed breast SPECT SMM images and corresponding US images from 40 patients with breast masses (21 malignant and 19 benign tumors). The quantitative data of SPECT SMM were obtained as the uptake ratio of lesion to contralateral normal breast. The morphologic features of the breast lesions on US were extracted and quantitated using the automated CAD software program. The diagnostic performance of SPECT SMM and CAD of US alone was determined using receiver operating characteristic (ROC) curve analysis. The best discriminating parameter (D-value) combining SPECT SMM and the CAD of US was created. The sensitivity, specificity and accuracy of combined two diagnostic modalities were compared to those of a single one. Results: Both SPECT SMM and CAD of US showed a relatively good diagnostic performance (area under curve = 0.846 and 0.831, respectively). Combining the results of SPECT SMM and CAD of US resulted in improved diagnostic performance (area under curve =0.860), but there was no statistical differerence in sensitivity, specificity and accuracy between the combined method and a single modality. Conclusion: It seems that combining the results of SPECT SMM and CAD of breast US do not significantly improve the diagnostic performance for diagnosis of breast cancer, compared with that of SPECT SMM alone. However, SPECT SMM and CAD of US may complement each other in differential diagnosis of breast cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.435-443
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• 2008

Purpose: Gated myocardial perfusion SPECT provides not only myocardial perfusion status but also various functional parameters of left ventricle. We compared left ventricular ejection fraction, end-diastolic volume, LV mass by cardiac SPECT using Quantitative Gated SPECT (QGS), 4D-MSPECT software and standard 2D-echocardiography. Materials and Methods: One hundred fourteen patients (male 51, female 63; 29-85 years old, mean $61.3\;{\pm}\;13.3$ years old) with normal perfusion status on Tc-99m tetrofosmin gated myocardial perfusion SPECT were analyzed retrospectively. Ejection fraction (LVEF), End-diastolic volume (LVED), LV mass (LVM) were calculated using QGS, 4D-MSPECT, and LVEF, LVM using 2D-echocardiography. Statistical analysis including Bland-Altman plot was performed using $MedCalc^{(R)}$ (MedCalc software, Mariakerke, Belgium). Results: The correlation of LVEF between methods was good: 0.95/0.96 (stress/rest) between QGS and 4D-MSPECT, 0.79 between QGS and echocardiography, 0.79 between 4D-MSPECT and echocardiography (p<0.001). Using Bland-Altman plot, the 95% confidence interval of agreement between QGS and 4D-MSPECT ranged from -12.7% to 7.3% / from -12.2% to 6.5% (stress/rest). The agreement between QGS and echocardiography, 4D-MSPECT and echocardiography ranged from -17.4% to 24.0%, and -14.8% to 27.0% respectively. The correlation of LVM between methods was also good: 0.95 between QGS and 4D-MSPECT, 0.76 between QGS and echocardiography, 0.73 between 4D-MSPECT and echocardiography (p<0.001). The 95% confidence interval of agreement between QGS and 4D-MSPECT ranged from -33.8g to 14.1g (stress/rest), The 95% confidence interval of agreement between QGS and echocardiography, 4D-MSPECT and echocardiography ranged from -148.7 g to 21.8. g, and -142.8 g to 35.5 g, respectively. Conclusion: There was a good correlation for LVEF, LVEO, LVM among methods (QGS, 4D-MSPECT, echocardiography), but the variance between methods was big. Therefore, the functional parameters by each method cannot be used interchangeably.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.469-477
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• 2008

Purpose: The goal of this paper is to present the design and performance of a position encoding circuit for $16{\times}16$ array of position sensitive multi-anode photomultiplier tube for small animal PET scanners. This circuit which reduces the number of readout channels from 256 to 4 channels is based on a charge division method utilizing a resistor array. Materials and Methods: The position encoding circuit was simulated with PSpice before fabrication. The position encoding circuit reads out the signals from H9500 flat panel PMTs (Hamamatsu Photonics K.K., Japan) on which $1.5{\times}1.5{\times}7.0\;mm^3$ $L_{0.9}GSO$ ($Lu_{1.8}Gd_{0.2}SiO_{5}:Ce$) crystals were mounted. For coincidence detection, two different PET modules were used. One PET module consisted of a $29{\times}29\;L_{0.9}GSO$ crystal layer, and the other PET module two $28{\times}28$ and $29{\times}29\;L_{0.9}GSO$ crystal layers which have relative offsets by half a crystal pitch in x- and y-directions. The crystal mapping algorithm was also developed to identify crystals. Results: Each crystal was clearly visible in flood images. The crystal identification capability was enhanced further by changing the values of resistors near the edge of the resistor array. Energy resolutions of individual crystal were about 11.6%(SD 1.6). The flood images were segmented well with the proposed crystal mapping algorithm. Conclusion: The position encoding circuit resulted in a clear separation of crystals and sufficient energy resolutions with H9500 flat-panel PMT and $L_{0.9}GSO$ crystals. This circuit is good enough for use in small animal PET scanners.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.229-234
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• 2008

Purpose: A urea breath test (UBT) using C-14 or C-13 has been developed for identifying Helicobacter (H) pylori infection on the basis of urease production with release of labeled $CO_2$. We investigated if the C-14 and C-13 UBT have the difference to reflect the presence and degree of H. pylori infection detected by gastro-duodenoscopic biopsies (CBx) in the same patients. Materials and methods: Thirty eight patients (M:F = 28:10, age $53.4{\pm}13.0$ yrs) with upper gastrointestinal symptoms such as indigestion, gastric fullness or pain consecutively underwent C-14 UBT, GBx and C-13 UBT within one week before medications. For the C-14 UBT, a single breath sample was collected at 10 minutes after ingestion of C-14 urea (37 KBq) capsule and counting was done in a liquid scintillation counter for 1 minute, and the results were classified as positive (${\ge}$ 200 dpm), intermediate (50-199 dpm) or negative (50 dpm). For the C-13 UBT, the results were classified as positive (${\ge}2.5\%_{\circ}$) or negative ($<2.5\%_{\circ}$). The results of GBx with Giemsa stain were graded 0 (normal) to 4 (diffuse) according to the distribution of H. pylori by the Wyatt method. We compared C-14 UBT and C-13 UBT results with GBx grade as a gold standard. Results: The prevalence of H. pylori infection by GBx with Giemsa stain was 25/38 (65.8%). In the assessment of the presence of H. pylori infection, the C-14 UBT global performance yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 92.0%, 92.3%, 95.8%, 91.7% and 92.1%, respectively. However, the C-13 UBT had sensitivity, specificity, PPV, NPV and accuracy of 96.0%, 84.6%, 92.3%, 91.7% and 92.1%, respectively. The more significant correlation in C-14 than C-13 UBT (r=0.948 vs r=0.819, p <0.001) was found between the value of UBT and the grade of distribution of H. pylori infection. Conclusion: We conclude that the diagnostic performance between C-14 and C-13 UBT to detect H. pylori infection is not significantly different, but the value of C-14 UBT more significantly reflects the degree of bacterial distribution.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.41-44
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• 2010

Purpose: Along with recent advances in PET/CT instrumentation and imaging technology, the number of patients has also been steadily increasing. This resulted in the increased radiation exposure to radiation workers in PET/CT rooms. In this study, we installed a radiation shield and investigated whether it could reduce radiation exposure to the workers and thus enhance job satisfaction. Materials and Methods: A radiation shield is composed of 5 cm thick lead and has a structure in which a radiation worker sits and watches a patient through lead glass while injecting radiopharmaceutical to the patient. Quarterly absorbed dose of radiation workers was measured using thermoluminescence dosimeters (TLD) and the results were compared for six months each before and after installation of the radiation shield. Exposure dose was also measured using a pocket dosimeter placed at the same location in the front and the back of the radiation shield. In addition, frequency of use of the shield and job satisfaction of radiation workers were investigated using a survey. Results: Quarterly absorbed dose of radiation workers was 2.70 mSv on average before installation of new radiation shield, whereas that dropped to 2.13 mSv after installation of radiation shield, reducing radiation exposure dose by 21%. Exposure dose on the front side of the shield was 61.2 R, whereas that on the back side of shield was 2.8 R. According to the survey, 85% of workers used the shield and were satisfied with the outcome: each radiation worker made injections to patients average of 6.5 times/day and preferred sitting to standing while injecting radiopharmaceutical to patients. Conclusion: Use of radiation shield reduced the exposure dose of radiation workers, which is the ultimate goal of radiation protection to minimize radiation exposure and is an appropriate method for the improvement of hospital working environment. Furthermore, we found that use of radiation shield not only relieves physical and psychological burden of radiation workers but also enhances job satisfaction. This result indicates that use of radiation shield is important for improvement of the radiation workers' job environment in terms of radiation protection.

• Radiation Oncology Journal
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• v.28 no.1
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• pp.9-15
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• 2010

Purpose: This study was performed to examine the neck failure patterns after a complete response (CR) to definitive radiotherapy for advanced head and neck cancer patients, as well as evaluate the clinical significance of the results of this study. Materials and Methods: Between 1987 and 2008, the clinical data of patients who had been treated with radical radiotherapy for primary squamous cell carcinomas and enlarged cervical lymph nodes was analyzed retrospectively. Ultimately, the cases that showed CR of the cervical lymph node lesions to full-dose radiotherapy were included in this study. The recurrent rate and sites in the cervical lymphatic area were evaluated periodically by radiologic imaging studies, along with some factors which might have affected the rate of recurrence. Results: A total of 73 patients who achieved CR in neck area after radiotherapy were included in this study. The rate of subsequent neck failure among those patients was 19.2%. There was only a 5.5% failure rate in the 55 patients who underwent radiotherapy in their primary site. Eighty percent of the recurrent cases were found within 3 years (median follow-up, 68 months). The majority of neck recurrent cases (47%) were accompanied with the failure of the primary lesions. The initial response of the primary site and the method of radiotherapy simulation were significant prognostic factors associated with the nodal recurrence rate. Conclusion: The recurrence rate of cervical nodes in patients with CR to radiotherapy in the primary site and neck area was about 5%. These patients could be followed up with close observation without a planned neck dissection.

• Childhood Kidney Diseases
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• v.13 no.1
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• pp.40-48
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• 2009

Purpose : This study was performed to identify factors related to the resolution of primary vesicoureteral reflux (VUR) in infants. Methods : We reviewed 183 infants (M : F=149 : 34) diagnosed as urinary tract infection (UTI) between February 2002 and July 2007 at Sanggye Paik Hospital. The diagnosis of UTI was made by culture from a urine specimen obtained by suprapubic puncture (n=97), catheterization (n=83), or collection bag method (n=3, twice positive culture of same organism). All of the infants were performed renal ultrasonography, DMSA scan and voiding cystourethrography (VCUG) study. Follow-up imaging consisted of contrast VCUG or direct isotope VCUG at interval of 1 year. We evaluated the relationship of clinical and laboratory finding, radiologic finding in infants with VUR. Results : Among 51 VUR patients, 18 infants had grade I-II, 12 infants had grade III and the other 21 patients had grade IV-V. Abnormal findings including hydronephrosis on renal ultrasonography were not correlated with severity of VUR. However, the incidence of renal defect in the first DMSA scan showed a tendency of direct correlation with severity of VUR in female patients only (P<0.001). There was significant difference of resolution rate in three VUR groups (grade I-II, III, IV-V) in male patients only (P=0.025). Resolution rate was higher for male patients with unilateral VUR than bilateral (P<0.001). But unilaterality had not any affect on VUR resolution in female VUR patients (P=0.786). Resolution rate was higher for VUR patients without renal scar than VUR patients with renal scar (P<0.001). Conclusion : According to our findings, grade of VUR, laterality and renal scar are the factors that contribute to resolution of primary VUR in male and female infants differently.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.110-122
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• 2009

Purpose: Nowadays, A medical institution assesment could get more interest about a quality of medical services from many hospitals that developed the active activities for improving medical services. Also, there is an other additional issue which is the patients risk management. Uijeongbu ST. Mary's hospital Nuclear Medicine department has been changed many work process after PET-CT introduction and renovation of its place since 2008. Therefore, modified structure and the way of existing work process have contained risk factors. The purpose of this study would be the appropriate risk management process while imaging examination process, the removal risk factors and improved activities through the analysis risk factors. Materials and Methods: Nuclear Medicine department new process should analysis through many-sided, Firstly, make and trained risk management manual after then apply an actual work. Result analysis showed the number of risk accident occurrence that comparing the last year and after the improved activities. Secondly, producing risk management public relations film has been showed an applicable patient after then the customer service measurement checked for a hundred patient by questionnaire. Lastly, Risk factors were eliminated through the facilities participation improving activities which could change for the better risk factors. Results: The number of safety accident occurrence(medication error, fall and collision) were checked as zero after the improving activities both PET-CT and gamma camera examination. The results of questionnaire showed as follows; 74% marked as understanding of the test process and 81% checked "satisfaction" after the public relations film showing. The question "Did you consider about the risk factors?", both PET-CT and gamma camera checked as 94% and 89% respectively. Customer risk management could be accomplished effectively through the improving activities at the nuclear medicine department. Conclusions: The study would be an opportunity that spread risk factors were systematically showed and analyzied. Also, It showed the possibility of the minimized safety accident and its feedback, if application of the response manuel that could be a standard of radiology technician's work method to react safety accident. It was the more effective that visual material could be easy to approach as a methodology of risk factors. As far as I have concerned that It could help the safety and convenience through continuous and detailed activities that offer to patients.