[en] Electrocardiogram-gated single photon emission computed tomography (SPECT) provides valuable information in the assessment of both myocardial perfusion and ventricular function. Tl-201 is a suboptimal isotope for gating. Tl-201 images are more blurred compared with Tc-99m tracers due to the increased amount of scattered photons and use of a smooth filter. The average myocardial count densities are approximately one-half those of conventional technetium tracers. However, Tl-201 is still widely used because of its well-established utility for assessing myocardial perfusion, viability and risk stratification. Gated SPECT with Tl-201 enables us to assess both post-stress and rest left ventricular volume and function. Previous studies with gated Tl-201 SPECT measurements of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) have shown high correlation with first-pass radionuclide angiography, gated blood pool scan, Tc-99m-MIBI gated SPECT, contrast ventriculography, echocardiography, and 3-dimensional magnetic resonance imaging. However, problems related to these studies include few agreement data of EDV and ESV, use of a reference method that is likely to have the same systemic errors (gated Tc-99 m-MIBI SPECT), and other technical factors related to the count density of gated SPECT. With optimization of gated imaging protocols and more validation studies, gated Tl-201 SPECT would be an accurate method to provide perfusion and function information in patients with coronary artery disease

[en] The purpose of this study was to evaluate the feasibility and efficacy of beta-radiation therapy with a rhenium-188-mercaptoacetyltriglycine (^I88Re-MAG₃) filled balloon to prevent tissue hyperplasia secondary to stent placement in a rabbit esophageal model. Fifteen rabbits were divided into the three study groups. The ten rabbits having the radioactive balloon dilation performed immediately after stent placement were scheduled to be sacrificed at six weeks; the 20 Gy (Group I, n = 5) or 40 Gy (Group II, n 5) at 1 mm away from the balloon surface were also sacrificed at six weeks. The remaining five rabbits that had conventional balloon dilation done immediately after stent placement were scheduled to be sacrificed six weeks later; this was the control group (Group III). At follow-up, we obtained esophagography and the histologic findings (epitheIial layer thickness, degree of destruction of the muscularis propria, and degree of submucosal inflammatory cell infiltration) at both the normal area and the mid-stent area for each esophageal specimen after sacrificing each rabbit. The differences among the three groups were statistically assessed using Kruskal-Wallis and Mann-Whitney U tests. There were no complications such as migration after stent placement. Nine of the rabbits died 1-3 weeks after stent placement and the stents were partially obstructed with a lot of residue, so it was impossible to compare the esophagographic findings among the three groups. Esophageal perforation (n = 6) and mucosal reddish changes (n = 5) of the esophagus adjacent to the stent were observed only for rabbits of group I or II. The esophageal mucosa displayed smoothness in group I and II, and the esophageal mucosa displayed nodularity in group III. The degree of destruction of the muscularis propria was significantly higher in group I or II when compared to group III (p<0.05). Beta-irradiation using a ^l88Re-MAG₃-filled balloon dilation has the potential for preventing tissue hyperplasia secondary to stent placement in a rabbit esophageal model

[en] We prepared 3'-deoxy-3'-[¹⁸F]fluorothymidine ([¹⁸F]FLT) from 3'-O-nosyl thymidine derivative 3 or its pyrimidine ring N-BOC-protected analogue 5 and optimized [¹⁸F]fluorination condition for a high radiochemical yield. The optimal condition for [¹⁸F]fluorination with precursor 3 was 30 mg (41.1 μmol)/300 μl CH₃CN at 130 degree sign C for 5 min, while precursor 5 required 34 mg (40 μmol)/300 μl CH₃CN at 110 degree sign C for 5 min. After HPLC purification at neutral pH, we achieved high radiochemical yields of 40 ± 5.2% and 42 ± 5.4% (decay-corrected) within 60 min of preparation time with radiochemical purities of >97%

[en] We evaluated a rapid preparation procedures for the labeling and quality control of ^99mTc-ECD, MAG₃ and MIBI using microwave heating and Sep-Pak cartridges. ^99mTc labeling of ECD, MAG₃, and MIBI kit preparation was performed according to the package inserts with microwave heating modification. Heating time was 10-15 sec, and heating was performed with 3 mm plastic bottle with screw cap to prevent radiation contamination. Labeling efficiency was obtained with C₁₈ or Alumina N Sep-Pak cartridges. The radiochemical purity of 93 ∼ 96% for ^99mTc-ECD and 95 ∼ 99% for ^99mTc-MIBI was obtained using Alumina N Sep-Pak cartridge. The optimum irradiation time of microwave method for 3 ml ^99mTc-labeled radiopharmaceutical solution was 10 sec for ^99mTc-ECD and ^99mTc-MIBI, and 15 sec for ^99mTc-MAG₃. The results of quality control data with Sep-Pak cartridges were well correlated wth TLC method. The total preparation time of these radiopharmaceuticals was 5 ∼ 6 min including quality control procedure. This study demonstrates that radiopharmaceuticals preparation by microwave heating and quality control by Sep-Pak cartridges can be efficiently utilized as an alternative to the recommended method by manufacture's manual

[en] Clinical features of 406 patients with histologically verified thyroid carcinomas were investigated from May, 1978 to April, 1985 at the Seoul National University Hospital with the following results. 1) The incidence of thyroid cancer according to their histological classification was 79. 8% of papillary carcinoma, 14.5% of follicular carcinoma, 1.5% of medullary carcinoma, 2.2% of anaplastic carcinoma, 2 cases of squamous carcinoma and 3 cases of lymphoma. 2) The age distribution showed the peak incidence in the fourth decade (25.1%), followed by the fifth and the third decade. 3) The ratio of male to female patients was 1:6.1. The ratio is 1:5.9 in papillary carcinoma and 1:8.8 in follicular carcinoma. 4) The mean age was 40.2 year in papillary carcinoma, 37.4 year in follicular carcinoma, 36.5 year in medullary carcinoma, 60.3 year in anaplastic carcinoma, 62.0 year in squamous carcinoma, 59.7 year in lymphoma. 5) The diameter of the thyroid masses was smaller than 1.5 cm in 19.9% of the patients, from 1.5 cm to 5 cm in 50.5%, from 5 cm to 10 cm in 25.4% and larger than 10 cm in 25.4%. 6) Metastasis to the regional lymph nodes at diagnosis was noted in 44.2% of total patients, and distant metastasis was 5%, and local infiltration was 44.2%. 7) The clinical staging was revealed 42.1% of the patients in stage I, 9.1% in stage II, 35.7% in stage III, 5.2% in stage IV, and 7.9% in undetermined stage.

[en] We evaluated the factors affecting changes in the postoperative glomerular filtration rate (GFR) after unilateral nephrectomy in living kidney donors and patients with renal disease. We studied 141 subjects who underwent living donor nephrectomy for renal transplantation (n=75) or unilateral nephrectomy for renal diseases (n=66). The GFR of the individual kidney was determined by Tc-99m DTPA scintigraphy before and after nephrectomy. By performing multiple linear regression analysis, we evaluated the factors that are thought to affect changes in GFR, such as age, sex, body mass index (BMI), preoperative GFR, preoperative creatinine level, operated side, presence of diabetes mellitus (DM), presence of hypertension (HTN), and duration of follow-up. In both the donor nephrectomy and the disease nephrectomy groups, GFR increased significantly after nephrectomy (46.9±8.4 to 58.1±12.5 vs. 43.0±9.6 to 48.6±12.8 ml/min, p<0.05). In the donor nephrectomy group, age was significantly associated with change in GFR (β=-0.3, P<0.005). In the disease nephrectomy group, HTN, preoperative creatinine level, and age were significantly associated with change in GFR (β=-6.2, p<0.005; β=-10.9, p<0.01; β=-0.2, p<0.01, respectively). This compensatory change in GFR was not significantly related to sex, duration of follow-up, or operated side in either group. The compensatory change in the GFR of the remaining kidney declined with increasing age in both living kidney donors and patients with renal disease.

[en] Although α-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for α-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for α-fetoprotein (Riakey AFP IRMA CT^R, Sin-Jin Medics, Seoul, Korea). We evaluated intra-and inter-assay precision, recovery rate, parallelism, and sensitivity of serum α-fetoprotein measurement using Riakey AFP IRMA CT^R kit. The values of α-fetoprotein measured by Riakey AFP IRMA CT^R kit were compared with those measured by two foreign commercial kits (α-fetoproteina of Radim and α-feto.riabead of Abbott). Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within 100±10%. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of α-fetoprotein by Riakey AFP IRMA CT^R and that by two foreign commercial kits(r=3D0.98). The first Korean domestic immunoradiometric kit for α-fetoprotein, Riakey AFP IRMA CT^R, performed well for clinical use.=20

[en] We compared captopril renal scintigraphic criteria for the diagnosis of renovascular hypertension by unilateral renal artery stenosis. The study group consisted of 24 patients (m/f = 16/8, age: 39±18 years) with unilateral renal artery stenosis who underwent renal artery revascularization and captopril renal scintigraphy with ^99mTc-diethylenetriaminepentaacetic acid between May 1995 and April 2004. The blood pressure response was classified as cure/improvement or failure. We evaluated captopril-induced changes in relative function (BCfun) and renogram grade (0 to 5: 0 = normal, and 5 = renal failure pattern without measurable uptake) (CBren) and the difference of renograms between the normal and stenotic kidney on captopril scan (CNren). Eight of 24 patients were cured and 11 improved and 5 patients were classified as failed revascularization. Significant predictors of a cure or improvement of blood pressure were younger age, stenosis by fibromuscular dysplasia or arteritis, BCfun, CBren and CNren. Areas under the receiver operating characteristic curve of age, BCfun, CBren and CNren were not significantly different. Positive and negative predictive values of predictors were 100% and 42% (age ≤ 38); 92% and 50% (BCfun≥ 1 %); 92% and 75% (CBren≥ 1), and 90% and 60% (CNren≥ 1), respectively. Captopril induced changes in renal function and renogram can reliably predict hypertension response to revascularization. Renogram pattern on captopril scan can diagnose renovascular hypertension without baseline data in patients with unilateral renal artery stenosis

[en] In general, hot nodules on technetium scan are regarded as benign tumors, and usually no further work up for malignancy is indicated, if they are truly autonomous. The authors experienced two cases of thyroid carcinoma presenting as hot nodule on technetium-99m pertechnetate thyroid scintigraphy. One case with papillary carcinoma, and other case with follicular carcinoma are presented in addition to a review of the literature.

[en] Metabolic imaging with FDG has shown to be useful in the assessment of myocardial viability in patients with ischemic cardiomyopathy. However, FDG PET is dependent on substrate availability and hormonal level, and experience in diabetes is limited. The purpose of this study was to evaluate the predictive accuracy of reversible LV function by NH₃/FDG PET in patients with diabetes and severe LV dysfunction. The study population consisted of 7 patients with diabetes and severe multivessel coronary artery disease (LVEF of less than 30%), who underwent NH₃/FDG PET prior to CABG. Left ventricle was divided into 13 segments, and myocardial uptake of NH₃ or FDG in each segment was graded. Tissue viability was assessed by the combined interpretation of perfusion and metabolism. Uptake pattern of individual artery territory was classified as normal, mismatch or match according to segmental uptake patterns. Regional and global LV function were determined with echocardiography prior to and after CABG. Preoperative wall motion of 19 vascular territories was akinetic in 3, severe hypokinetic in 11, mild hypokinetic in 4, and normal in 1 territory. Postoperarive wall motion was severe hypokinetic in 5, mild hypokinetic in 5, and normal in 9 territories. According to patterns on NH₃/FDG PET, 8 were classified as mismatch, 10 as normal, and 1 as match. Of 18 vascular terriories with abnormal preoperative wall motion, regional wall motion improved in 6 of 8 mismatch (75%) and 5 of 9 (56%) normal territories resulting in sensitivity of 100%. In 1 territory with perfusion and metabolism match, there was no improvement of regional wall motion. The LVEF improve from 26±2% (mean ±SD) to 43±4% in all patients (p<0.001). Despite of the referral bias and small number of patients, these data suggest that FDG PET has comparable predictive accuracy of regional and global wall motion improvement after CABG in patients with diabetes