• The Korean Journal of Nuclear Medicine Technology
• /
• v.16 no.1
• /
• pp.80-85
• /
• 2012

Purpose: The whole body bone scan is an examination that visualizing physiological change of bones and using bone-congenial radiopharmaceutical. The patients are intravenous injected radiopharmaceutical which labeled with radioactive isotope ($^{99m}Tc$) emitting 140 keV gammarays and scanned after injection. The 3 principles of radiation protection from external exposureare time, distance and shielding. On the 3 principles of radiation protection basis, radiopharmaceutical might just as well be injected rapidly for reducing radiation because it might be the unopened radiation source. However the radiopharmaceuticals are injected into patient directly and there is a limitation of distance control. This study confirmed the change of radiation exposure as change of distance from radiopharmaceutical and observed the change of radiation exposure afte rsetting a shelter for help to control radio-technician's exposure. Materials & methods: For calculate the average of injection time, the trained injector measured the injection time for 50 times and calculated the average (2 minutes). We made a source as filled the 99mTc-HDP 925 MBq 0.2 mL in a 1 mL syringe and measured the radiation exposure from 50 cm,100 cm,150 cm and 200 cm by using Geiger-Mueller counter (FH-40, Thermo Scientific, USA). Then we settled a lead shielding (lead equivalent 6 mm) from the source 25 cm distance and measured the radiation exposure from 50 cm distance. For verify the reproducibility, the measurement was done among 20 times. The correlation between before and after shielding was verified by using SPSS (ver. 18) as paired t-test. Results: The radiation doses according to distance during 2 minutes from the source without shielding were $1.986{\pm}0.052{\mu}$ Sv in 50 cm, $0.515{\pm}0.022{\mu}$ Sv in 100 cm, $0.251{\pm}0.012{\mu}$ Sv in 150 cm, $0.148{\pm}0.006{\mu}$ Sv in 200 cm. After setting the shielding, the radiation dose was $0.035{\pm}0.003{\mu}$ Sv. Therefore, there was a statistical significant difference between the radiation doses with shielding and without shielding ($p$<0.001). Conclusion: Because the great importance of whole body bone scan in the nuclear medicine, we should make an effort to reduce radiation exposure during radiopharmaceutical injections by referring the principles of radiation protection from external exposure. However there is a limitation of distance for direct injection and time for patients having attenuated tubules. We confirmed the reduction of radiation exposure by increasing distance. In case of setting shield from source 25 cm away, we confirmed reducing of radiation exposure. Therefore it would be better for reducing of radiation exposure to using shield during radiopharmaceutical injection.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.1
• /
• pp.42-48
• /
• 2007

Purpose: The purpose of this study is to image metastaic lung melanoma model with optimal pre-conditions for animal handling by using $[^{18}F]FDG$ small animal PET and clinical CT. Materials and Methods: The pre-conditions for lung region tumor imaging were 16-22 h fasting and warming temperature at $30^{\circ}C$. Small animal PET image was obtained at 60 min postinjection of 7.4 MBq $[^{18}F]FDG$ and compared pattern of $[^{18}F]FDG$ uptake and glucose standard uptake value (SUVG) of lung region between Ketamine/Xylazine (Ke/Xy) and Isoflurane (Iso) anesthetized group in normal mice. Metastasis tumor mouse model to lung was established by intravenous injection of B16-F10 cells in C57BL/6 mice. In lung metastasis tumor model, $[^{18}F]FDG$ image was obtained and fused with anatomical clinical CT image. Results: Average blood glucose concentration in normal mice were $128.0{\pm}23.87$ and $86.0{\pm}21.65\;mg/dL$ in Ke/Xy group and Iso group, respectively. Ke/Xy group showed 1.5 fold higher blood glucose concentration than Iso group. Lung to Background ratio (L/B) in SUVG image was $8.6{\pm}0.48$ and $12.1{\pm}0.63$ in Ke/Xy group and Iso group, respectively. In tumor detection in lung region, $[^{18}F]FDG$ image of Iso group was better than that of Ke/Xy group, because of high L/B ratio. Metastatic tumor location in $[^{18}F]FDG$ small animal PET image was confirmed by fusion image using clinical CT. Conclusion: Tumor imaging in small animal lung region with $[^{18}F]FDG$ small animal PET should be considered pre-conditions which fasting, warming and an anesthesia during $[^{18}F]FDG$ uptake. Fused imaging with small animal PET and CT image could be useful for the detection of metastatic tumor in lung region.

• Clinical and Experimental Pediatrics
• /
• v.45 no.6
• /
• pp.773-782
• /
• 2002

Purpose : To identify the necessity of more reasonable diagnostic criteria and the possibility of early prediction of coronary involvement in the higher risk group, we investigated and compared clinical and laboratory findings in the acute phase and coronary involvements in those younger (n=17) and older(n=53) than one year of age in Kawasaki disease(KD). Methods : Retrospective chart reviews were performed on 70 patients with KD who were admitted to the Chung-Ang University Hospital from April 1997 to May 2001. Results : Male were significantly higher in the younger age group(M : F ratio 3.3 : 1 vs. 1.0 : 1, P=0.004). Fever durations before intravenous immunoglobulin(IVIG) and echocardiography were significantly shorter in the younger group($4.6{\pm}1.3$ vs. $6.2{\pm}2.5$, P=0.004 vs. 0.01, respectively). Cases meeting typical diagnostic criteria were significantly less in the younger group(P=0.006). In the laboratory findings, serum albumin, BUN and $K^+$ levels in the acute febrile phase were significantly higher in the younger group(P=0.002, 0.006, <0.001, respectively) and incidences of coronary artery dilatation in the acute phase were significantly higher in the younger group(P=0.01). Conclusion : Although less met the typical diagnostic criteria of KD, infants younger than one year of age are more susceptible to coronary artery change in the acute febrile phase. Therefore, KD should be entertained as a diagnostic possibility in young infants with prolonged fever without distinct fever focus, and echocardiography should be considered as part of the evaluation of these patients, and then early diagnosis and prompt IVIG should be conducted.

• Nuclear Medicine and Molecular Imaging
• /
• v.40 no.5
• /
• pp.263-270
• /
• 2006

Purpose: Several radioisotope-labeled thymidine derivatives such as $[^{11}C]$thymidine was developed to demonstrate cell proliferation in tumor. But it is difficult to track metabolism with $[^{11}C]$thymidine due to rapid in vivo degradation and its short physical half-life. 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) was reported to have the longer half life of fluorine-18 and the lack of metabolic degradation in vivo. Here, we described the synthesis of the 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) and compared with $([^{18}F]FET)\;and\;([^{18}F]FDG)$ in cultured 9L cell and obtained the biodistribution and PET image in 9L tumor hearing rats. Material and Methods: For the synthesis of $[^{18}F]$FLT, 3-N-tert-butoxycarbonyl-(5'-O-(4,4'-dimet hoxytriphenylmethyl)-2'-deoxy-3'-O-(4-nitrobenzenesulfonyl)-${\beta}$-D-threopentofuranosyl)thymine was used as a FLT precursor, on which the tert-butyloxycarbonyl group was introduced to protect N3-position and nitrobenzenesulfonyl group. Radiolabeling of nosyl substitued precursor with $^{18}F$ was performed in acetonitrile at $120^{\circ}C$ and deproteced with 0.5 N HCI. The cell uptake was measured in cultured 9L glioma cell. The biodistribution was evaluated in 9L tumor bearing rats after intravenous injection at 10 min, 30 min, 60 min and 120 min and obtained PET image 60 minutes after injection. Results: The radiochemical yield was about 20-30% and radiochemical purity was more than 95% after HPLC purification. Cellular uptake of $[^{18}F]$FLT was increased as time elapsed. At 120 min post-injection, the ratios of tumor/blood, tumor/muscle and tumor/brain were $1.61{\pm}0.34,\;1.70{\pm}0.30\;and\;9.33{\pm}2.22$, respectively. The 9L tumor was well visualized at 60 min post injection in PET image. Conclusion: The uptake of $[^{18}F]$FLT in tumor was higher than in normal brain and PET image of $[^{18}F]$FLT was acceptable. These results suggest the possibility of $[^{18}F]$FLT at an imaging agent for brain tumor.

• Neonatal Medicine
• /
• v.18 no.1
• /
• pp.82-88
• /
• 2011

Purpose: This study aims to describe the clinical characteristics of adrenal insufficiency-associated hypotension in preterm infants and the effects of hydrocortisone therapy on their cardiovascular system and serum electrolytes. Methods: Twelve preterm infants less than 32 gestational weeks admitted to neonatal intensive care unit (NICU) of the Seoul National University Bundang Hospital from January 2007 to August 2009 with clinical and laboratory findings suggestive of adrenal insufficiency were analyzed retrospectively. Results: Gestational age was 27.8${\pm}$2.5 weeks and birth weight was 1,110${\pm}$307 g. Postnatal age, postmenstrual age, weight at the onset of adrenal insufficiency-associated hypotension were 19${\pm}$7 day, 30.6${\pm}$2.4 weeks, 1,285${\pm}$365 g. In preterm infants who showed vasopressor resistance, intravenous hydrocortisone was started with a stress dose of 4 mg/kg/day, maintained for 2.2${\pm}$0.7 days, and then tapered. Serum cortisol concentration before hydrocortisone administration was 11.6${\pm}$4.1 mg/dL. Mean blood pressure increased from 25.0${\pm}$5.4 mmHg to 35.0${\pm}$5.3 mmHg, 38.3${\pm}$8.0 mmHg and 41.9${\pm}$6.5 mmHg at time of hydrocortisone administration and 2, 4 and 6 hours after hydrocortisone administration. Urine output increased from 0.9${\pm}$0.6 mL/kg/hr to 4.1${\pm}$3.4 mL/kg/hr. Twelve hours after the administration of hydrocortisone, dopamine requirement decreased from 11.0${\pm}$2.9 $\mu$g/kg/min to 8.0${\pm}$2.3 $\mu$g/kg/min, and to 5.5${\pm}$3.4 ${\mu}g$/kg/min after 24 hours. Serum sodium concentration was increased from 130${\pm}$4 mEq/L to 136${\pm}$4 mEq/L, serum potassium concentration was decreased from 6.1${\pm}$1.1 mEq/L to 4.6${\pm}$0.6 mEq/L before and 12 hours after hydrocortisone administration. Conclusion: In preterm infants with adrenal insufficiency-associated hypotension, hydrocortisone administration improved blood pressure and urine output, decreased vasopressor requirement, and normalized serum electrolyte abnormalities.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.5
• /
• pp.393-402
• /
• 2000

Purpose: Tc-99m-MIBI (MIBI) and Tc-99m-Tetrofosmin (TF) are commonly used for scintimammog (SMM). We compared the diagnostic ability of SMM using Tc-99m-MIBI and Tc-99m-TF for the diagnosis of breast mass. Materials and Methods: The study subjects were comprised of 123 breast lesior 86 normal breasts of 114 patients who underwent SMM. Bilateral prone images and anterior supine images obtained at 5 minutes and 1 or 3 hours after intravenous injection of 740 MBq of either MIBI or TF. of tumors were not significantly different between the MIBI and TF groups. First, two observers read the SMM without clinical information (1st interpretation), then read again with information about location (2nd interpretation). Sensitivity and specificity of each radiopharmaceutical for the diagnosis of cancer were evaluated in terms of image acquisition time, tumor size, and location. Results: The SMM a good agreement between two observers for 1st and 2nd interpretation, except for TF SMM at 3 hr. first interpretation, the sensitivities at 5 min, 1 hr, and 3 hr were not significantly different between MIBI TF SMM (81.6%, 80.0%, 60.9% in MIBI vs. 88.9%, 80.6%, 42.9% in TF), although the sensitivities of images were significantly lower than 5 min images in both MIBI and TF SMM. The specificity of TF at was superior to that of MIBI (81.5%, 90.0%, 82.9% in MIBI vs. 96.7%, 100%, 90.0% in TF, p<0.01 MIBI TF at 5 min). For the second interpretation with information of mass location, the sensitivities at 3 hr were significantly lower than 5 min images (86.8%, 86.7%, 78.3% in MIBI vs. 88.9%, 93.5%, 57.1% between MIBI and TF SMM. However, there was no significant difference in the specificity (60.0%, 75.0% for MIBI vs. 86.7%, 100%, 100% for TF). MIBI and TF SMM showed lower sensitivities for the with less than 1 cm than tumors with more than 1 cm. However, the location of tumors did not sensitivity and specificity between MIBI and TF SMM. Conclusion: The ability for the differential of breast tumor is similar between MIBI and TF SMM, and delayed image is not necessary. TF may be than MIBI considering the specificity of SMM without clinical information and labeling convenience.

• Progress in Medical Physics
• /
• v.22 no.1
• /
• pp.42-51
• /
• 2011

Nuclear medicine images (SPECT, PET) were widely used tool for assessment of myocardial viability and perfusion. However it had difficult to define accurate myocardial infarct region. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct size using polar map with adaptive threshold. Rat myocardial infarction model was induced by ligation of the left circumflex artery. PET images were obtained after intravenous injection of 37 MBq $^{18}F$-FDG. After 60 min uptake, each animal was scanned for 20 min with ECG gating. PET data were reconstructed using ordered subset expectation maximization (OSEM) 2D. To automatically make the myocardial contour and generate polar map, we used QGS software (Cedars-Sinai Medical Center). The reference infarct size was defined by infarction area percentage of the total left myocardium using TTC staining. We used three threshold methods (predefined threshold, Otsu and Multi Gaussian mixture model; MGMM). Predefined threshold method was commonly used in other studies. We applied threshold value form 10% to 90% in step of 10%. Otsu algorithm calculated threshold with the maximum between class variance. MGMM method estimated the distribution of image intensity using multiple Gaussian mixture models (MGMM2, ${\cdots}$ MGMM5) and calculated adaptive threshold. The infarct size in polar map was calculated as the percentage of lower threshold area in polar map from the total polar map area. The measured infarct size using different threshold methods was evaluated by comparison with reference infarct size. The mean difference between with polar map defect size by predefined thresholds (20%, 30%, and 40%) and reference infarct size were $7.04{\pm}3.44%$, $3.87{\pm}2.09%$ and $2.15{\pm}2.07%$, respectively. Otsu verse reference infarct size was $3.56{\pm}4.16%$. MGMM methods verse reference infarct size was $2.29{\pm}1.94%$. The predefined threshold (30%) showed the smallest mean difference with reference infarct size. However, MGMM was more accurate than predefined threshold in under 10% reference infarct size case (MGMM: 0.006%, predefined threshold: 0.59%). In this study, we was to evaluate myocardial infarct size in polar map using multiple Gaussian mixture model. MGMM method was provide adaptive threshold in each subject and will be a useful for automatic measurement of infarct size.

• Radiation Oncology Journal
• /
• v.15 no.2
• /
• pp.121-128
• /
• 1997

Purpose : To evaluate the effect of postoperative adjuvant radiation therapy and chemotherapy on the survival, pattern of failure and complication for locally advanced rectal carcinoma Materials and Methods : From October 1992 to September 1995, twenty eight patients with rectal carcinoma were treated by postoperative adjuvant radiation therapy and chemotherapy Radiation therapy was delivered with 6MV and 15MV linear accelerator, 180c0y fractions 5 day per week. Total radiation doses were 5040cGy in $B_{2+3}$ and 5580cGy in $C_{2+3}$. Within 4 weeks after radical surgery. 5-FU$(400mg/m^2/day)\;and\;Leucovorin(20mg/m^2/day)$ were administered by intravenous injection for 4 days during the first and fifth week of radiation therapy. The median follow up was 19 months with a range 2 to 47 months. Results : The 2 year overall survival and disease free survival rates were $78.6\%\;and\;70.8\%$, respectively. The 2 year overall survival was $93.0\%\;in\;B_{2+3}$ and $76.2\%\;in\;C_{2+3}$(p=0.11) The 2 year disease free survival was $79.4\%\;in\;B_{2+3}\;and\;69.2\%\;in\;C_{2+3}(p=0.13)$. The overall failure rate was $21.42\%$(6/28) including $10.72\%$(3/28) locoregional recurrence, $3.62\%$(1/28) distant metastasis and $7.12\%$(2/28) locoregional recurrence with distant metastasis. The overall locoregional recurrence rate was $17.92\%$(5/28). The 2 year locoregional recurrence rates were $13.32\%(2/15)\;and\;23.12\%$(3/13) for respectively for $B_{2+3}\;and\;C_{2+3}$ The difference between the locoregional recurrence of $B_{2+3}\;and\;C_{2+3}$ patients was not significant(p=0.07). Complications developed in 13 patients$(46.42\%)$, including 8 dermatitis, 7 loose stool, 6 leukopenia, 4 tenesmus, 2 diarrhea. In Univariate analysis, there was no statistically significant factor except for tumor grade in locoregional recurrence, disease free survival and overall survival rate(p=0.04, 0.05, 0.04). Conclusion : This study sugges1s that postoperative adjuvant radiation therapy and chemotherapy is effective in patients with locally advanced rectal cancer. Therefore these results need to be confirmed with a long term follow-up and larger number of patients with the further clinical trials including prospective controlled studies.

• Radiation Oncology Journal
• /
• v.17 no.2
• /
• pp.113-119
• /
• 1999

Purpose : To evaluate possible acute toxicity and early response of concurrent radiation therapy and low dose daily cisplatin as a radiosensitizer in patients with locally advanced uterine cervical carcinomas. Materials and Method : From December 1996 to January 1999, 38 previously untreated Patients with locally advanced squamous cell carcinoma of the uterine cervix (from stage IIB to stage IIIB) were treated at Inha University Hospital. All patients underwent standard pretreatment staging Procedures after the initial evaluation by gynecologists and radiation oncologists. Sixteen Patients with huge cervical mass (>4 cm) were submitted to the group treated with concurrent radiation therapy and low dose daily cisplatin while the remainder was treated with radiation therapy alone. Radiation therapy consisted of 4500 cGy external beam irradiation to whole pelvis (midline block after 3000 cGy), 900$\~$1000 cGy boost to involved parametrium, and high dose-rate intracavitary brachytherapy (a total dose of 3000$\~$3500 cGy/500 cGy per fraction to point A, twice per week). In the group treated with low dose cisplatin concurrently, 10 mg of daily intravenous cisplatin was given from the 1st day of radiation therapy to the 20th day of radiation therapy. Acute toxicity was measured according to expanded common toxicity criteria of the NCI (C) Clinical Trials. Early response data were analyzed at minimum 4 weeks' follow-up after completion of the treatment protocol. Results: Hematolgic toxici쇼 was more prominent in patients treated with radiation therapy and cisplatin. Six of 16 patients (37.5$\~$) treated with radiation therapy and cisplatin and one of 22 patients (4.5$\~$) treated with radiation therapy alone experienced grade 3 leukopenia. In Fisher's exact test, there was statistically significant difference between two groups regarding leukopenia (P=0.030). There was no apparent difference in the frequency of gastrointestinal and genitourinary toxicity between two groups (P=0.066). Three of 16 patients (18.7$\~$) treated with radiation therapy and cisplatin and two of 22 patients (9.1$\~$) treated with radiation therapy alone experienced more than 5 kg weight loss during the treatment. There was no statistically significant difference on weight loss between two groups (P=0.63). Two patients on each group were not evaluable for the early response because of incomplete treatment. The complete response rate at four weeks' follow-up was 80$\~$(16/20) for the radiation therapy alone group and 78$\~$ (11/14) for the radiation therapy and cisplatin group. There was no statistically significant difference in early response between two treatment groups (P=0.126). Conclusion : This study led to the conclusion that the hematologic toxicity from the treatment with concurrent radiation therapy and low dose daily cisplatin seems to be more prominent than that from the treatment of radiation therapy alone. There was no grade 4 hematologic toxicity or mortality in both groups. The hematologic toxicity in both treatment groups seems to be well managable modically. Since the risk factors were not balanced between two treatment groups, the direct comparison of early response of both groups was not possible. However, preliminary results regarding early response for patients with bulky cervical tumor mass treated with radiation therapy and low dose daily cisplatin was encouraging. Longer follow-up is necessary to evaluate the survival data. A phase III study is needed to evaluate the efficacy of concurrent daily low dose cisplatin with radiation therapy in bulky cervical cancer.

• The Korean Journal of Nuclear Medicine
• /
• v.31 no.1
• /
• pp.73-82
• /
• 1997

Regional myocardial blood flow (rMBF) can be noninvasively quantified using N-13 ammonia and dynamic positron emission tomography (PET). The quantitative accuracy of the rMBF values, however, is affected by the distortion of myocardial PET images caused by finite PET image resolution and cardiac motion. Although different methods have been developed to correct the distortion typically classified as partial volume effect and spillover, the methods are too complex to employ in a routine clinical environment. We have developed a refined method incorporating a geometric model of the volume representation of a region-of-interest (ROI) into the two-compartment N-13 ammonia model. In the refined model, partial volume effect and spillover are conveniently corrected by an additional parameter in the mathematical model. To examine the accuracy of this approach, studies were performed in 9 coronary artery disease patients. Dynamic transaxial images (16 frames) were acquired with a GE $Advance^{TM}$ PET scanner simultaneous with intravenous injection of 20 mCi N-13 ammonia. rMBF was examined at rest and during pharmacologically (dipyridamole) induced coronary hyperemia. Three sectorial myocardium (septum, anterior wall and lateral wall) and blood pool time-activity curves were generated using dynamic images from manually drawn ROIs. The accuracy of rMBF values estimated by the refined method was examined by comparing to the values estimated using the conventional two-compartment model without partial volume effect correction rMBF values obtained by the refined method linearly correlated with rMBF values obtained by the conventional method (108 myocardial segments, correlation coefficient (r)=0.88). Additionally, underestimated rMBF values by the conventional method due to partial volume effect were corrected by theoretically predicted amount in the refined method (slope(m)=1.57). Spillover fraction estimated by the two methods agreed well (r=1.00, m=0.98). In conclusion, accurate rMBF values can be efficiently quantified by the refined method incorporating myocardium geometric information into the two-compartment model using N-13 ammonia and PET.