[en] Recently, [I-123]IPT SPECT has been used for early diagnosis of Parkinson's patients (PP) by imaging dopamine transporter. The dynamic time activity curves in basal ganglia (BG) and occipital cortex(OCC) without blood samples were obtained for 2 hours. These data were then used to measure dopamine transporters by operationally defined ratio methods of (BG-OCC)/OCC at 2 hrs, binding potential R_v=k_3/k4 using graphic method or R_A=(ABBG-ABOCC)/ABOCC for 2 hrs, where ABBG represents accumulated binding activity in basal ganglia (∫^120min₀ BG(t)dt) and ABOCC represents accumulated binding activity in occipital cortex (∫^120min₀ OCC(t)dt). The purpose of this study was to examine the IPT pharmacokinetics and investigate the usefulness of simplified methods of (BG-OCC)/OCC, R_A, and R_v which are often assumed that these values reflect the true values of k₃/k₄. The rate constants K₁, k₂, k₃ and k₄ to be used for simulations were derived using [I-123]IPT SPECT and aterialized blood data with a standard three compartmental model. The sensitivities and time activity curves in BG and OCC were computed by changing K₁ and k₃(only BG) for every 5 min over 2 hours. The value (BG-OCC)/OCC, R_A, and R_v were then computed from the time activity curves and the linear regression analysis was used to measure the accuracies of these methods. The rate constants K₁, k₂, k₃, k₄ at BG and OCC were 1.26±5.41%, 0.044±19.58%, 0.031±24.36%, 0.008±22.78% and 1.36±4.76%, 0.170±6.89%, 0.007±23.89%, 0.007±45.09%, respectively. The Sensitivities for ((ΔS/S)/(Δk₃/k₃)) and ((ΔS/S)/(ΔK₁/K₁)) at 30 min and 120 min were measured as (0.19, 0.50) and (0.61, 0.23), respectively. The correlation coefficients and slopes of ((BG-OCC)/OCC,R_A, and R_V) with k₃/k₄ were (0.98, 1.00, 0.09) and (1.76, 0.47, 1.25), respectively. These simulation results indicate that a late [I-123]IPT SPECT image may represent the distribution of the dopamine transporters. Good correlations were shown between (BG-OCC)/OCC, R_A or R_v and true k₃/k₄, although the slopes between them were not unity. Pharmacokinetic computer simulations may be a very useful technique in studying dopamine transporter systems

[en] Radiation therapy using CT simulation technique can provide shielding for normal tissue and significantly reduce radiation-induced xerostomia in head and neck cancer patient(pt)s. The aim of this study was to assess the salivary dysfunction after radiation therapy in pts with head and neck cancer and to evaluate the salivary shielding effect of CT simulation technique by salivary scintigraphy. Fifteen pts (mean age: 48±15) who had been irradiated to head and neck for various malignancies (papillary thyroid cancer: 5, nasopharyngeal cancer: 4, lymphoma: 3, other: 4) underwent salivary scintigraphy with Tc-99m pertechnetate before and 4-6 months after radiation theraphy (mean interval: 158±33 days). The mean neck radiation dose was 58±11 cGy. Ten salivary glands (9 parotid glands, 1 submandibular gland) were shielded from radiation (less than 30 cGy of mean dose in 80% volume of gland). Using salivary scintigraphy, secretory function (uptake₂₀; glandular uptake at 20 minute/ background uptake) and excretory function (EF: %washout after stimulation of orange juice) of each glands were obtained. Fifty seven salivary glands were analyzed. In irradiated glands (n=47), the EF values of both parotid and submanidibular glands were significantly, decreased compared with before radiation (59.3±26.4 vs 15.9±28.4, 56.6±22.9 vs 12.6±21.9 respectively, p<0.005) and the uptake₂₀ values of both parotid and submandibular glands were also significantly decreased after radiation (4.0±1.8 vs2.4±0.9, p<0.001, 5.3±1.9 vs 4.2±1.4, p<0.05). The uptake₂₀ and EF values of shielded glands before and after radiation therapy showed no significant difference (3.9±1.9 vs 3.9±2.4, 56.97±27.8 vs 55.9±28.5, respectively). In radiation therapy of head and neck cancer, salivary dysfunction can be prevented using radiation shield by CT simulation technique. Salivary scintigraphy is a useful non-invasive tool for quantitative assessment of radiation-induced salivary dysfunction and shielding effect

[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] 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] The prevalence of avascular necrosis (AVN) of femoral head in patients who receive immunosuppresive agents after renal transplantation is reported to be 4-29%. Among patients who develop AVN after renal transplantation, 80% become symptomatic within 2 years after transplantation. As the number of renal transplantation has been increased recently, early detection of femoral head AVN is very important because early surgical core decompression of femoral head can prevent collapse of the head. MRI is known to be very sensitive to diagnose femoral head AVN. However in three cases we report here, bone SPECT showed early changes of femoral head AVN, whereas MRI showed no specific abnormality. Case 1. A 53-year-old female received an allograft kidney transplantation in 1994. Preoperative bone scan was normal. She complained of both hip pain on Mar. 18 1997. Bone SPECT showed cold defect in both femoral heads but MRI showed no abnormality. After 3 months, bone SPECT and MRI showed AVN of both femoral heads. She underwent bilateral total hip replacement arthroplasty. AVN of femoral heads was confirmed by microscopic examination. Case 2. A 38-year-old female received an allograft kidney transplantation in Feb. 27 1997. Preoperative bone scan was normal. She ran a fever and creatinine was elevated from 1.2 to 2.8 mg/dL. She took high dose methylprednisolone therapy for acute reanl rejection. After two days, she complained pain in both hip joints and knee joints. Bone SPECT showed cold defects in both femoral heads but MRI showed no abnormality. A follow-up bone SPECT and MRI 20 days later revealed AVN of both femoral heads. Case 3. A 50-year-old male received an allograft kidney transplantation on Jul. 12 1995. Preoperative bone scan was normal. He complained of right hip pain on Jul, 26 1995. His bone SPECT showed cold defects in both femoral heads while MRI showed only minimal hip joint effusion. He also complained of left hip pain on Oct. 2 1995. He was admitted on Mar 17 1996 because of both hip pain and fever. MRI showed advanced AVN of femoral heads was confirmed by microscopic examination. Bone SPECT can diagnose early AVN of femoral head in renal allograft recipients when MRI could be normal

[en] The aim of our study was to determine the role of MR cholangiography (MRC) and hepatobiliary scintigraphy (HBS) in the assessemtn of recurrent bile duct obstruction after biliary surgery. Twenty-three patients (15 men and 8 women: mean age 49.8) with post-biliary operation state (16 biliary-enteric anastomoses and seven cholecystectomy) underwent a total of 28 MRC and 28 HBS using Tc-99m DISIDA within 3 days of each other. Interval between surgery and MRC or HBS ranged from 2 wk to 15 yr (median: 14 mon). MRC and HBS were analyzed for the presence of bile duct obstruction. The final diagnoses were cofirmed by percutaneous transhepatic biliary drainage or surgical operation in 11 of 28 cases and by the follow-up clinical course in the rests. Of 14 instances with bile duct obstruction (13 intrahepatic bile duct obstruction and 1 common bile duct obstruction), HBS showed complete intrahepatic bile duct (IHD) obstruction in 7, incomplete IHD obstruction in 5, parenchymal dysfuction in 1, and IHD dilation without obstructon in 1, resulting in sensitivity of 86% (12/14). MRC showed stone in 6, stricture in 4, IHD dilatation in 3, and normal in 1. The sensitivity of MRC was 71% (10/14). Fourteen instances were without obstruction. HBS showed no evidence of obstruction in all 14 instances (specificity 100%). However, stricture on MRC was found in 4 instances, resulting in specificity of 71% (10/14). HBS is useful in the diagnosis of recurrent bile duct obstruction after surgery. MRC is a useful modality for assessing the diagnosis of obstruction itself as well as the cause and location of bile duct obstruction. However, the specificity of MRC appears to be lower because of possible overestimation of stricture

[en] This prospective study was performed to evaluate the usefulness of preoperative radioimmunoscintigraphy and intraoperative scintimetric examination (radioimmunoguided surger: RIGS) using^99mTc-anti-CEA F(ab')₂ fragment. Nineteen patients with rectal cancer underwent preoperative whole body planar scintigraphy at 4 hours after injection of ^99mTc-anti-CEA F(ab')₂ fragment and SPECT imaging at 18 hours. Surgical operation was performed at 24 hours after injection. During laparotomy, radioactivities from intraabdominal viscera were measured by gamma probe. The radioactivities from excised tumor and lymph nodes were also measured and compared with pathology. All nineteen patients were confirmed to have adenocarcinomas in the rectum. Twenty-seven of 97 excised lymph node groups had metastasis and 2 patients had liver metastasis in pathology. Preoperative radioimmunoscintigraphy detected primary tumors in 11 patients (sensitivity 55%) and it could not detect any lymph nodes or liver metastasis. All patients showed high radioactivity in the kidneys, liver, spleen, and major vessels in intraoperative measurement by gamma probe, and tumor activity was not discriminated from background activity. However, radioactivity from excised tumor was higher than normal rectum (T/B ratio; 3,47±2.25). When excised lymph node activity/background activity ratio >1.5 was considered as positive criteria of metastasis, sensitivity, specificity, positive and negative predictive values were 78.6%, 73.9%, 55.0% and 89.5%, respectively. Radioimmunoscintigraphy using ^99mTc-anti-CEA F(ab')₂ has no additional value for preoperative staging and use of early RIGS using ^99mTc-anti-CEA F(ab')₂ is inappropriate. For early RIGS using ^99mTc labeled antibodies in rectal cancer patients, further development of more specific antibodies and methods to reduce background activity are needed.=20

[en] Longterm F/U evaluation of cerebrovascular hemodynamic changes after EDAMS is important because childhood moyamoya disease has a progressive nature and EDAMS is an indirect revascularization method. We evaluated cerebro-vascular hemodynamic changes of moyamoya pts during 2 yr after EDAMS with Acz-SPECT and correlated with MRA finding. 23 operated cerebral hemispheres of the 21 childhood moyamoya pts (M/F: 10/11, mean age 8±3 yrs) were evaluated with Acz-SPECT using ^99mTc-ECD and MRA within 1 mo before, 1 yr ( 6 ±3 mo) and 2 yr (21 ±7 mo) after EDAMS. 10 pts also underwent frontal encephalo-galeo-synangiosis. Regional cerebral blood flow (rCBF) and cerebrovascular reserve (rCVR) of 8 cortical regions in each hemisphere (2 anterior cerebral artery (ACA), 4 mid-cerebral artery (MCA), and 2 posterior cerebral artery (PCA) territories) were scored as 5 grade scale (0=perfusion defect to 4=normal). Perfusion index (PI) was defined as the sum scores of rCBF and rCVR in each territory. Arterial stenosis and transdural collaterals were also evaluated. The changes of PIs in each territory and the changes of cerebral arterial stenosis with collateral formation at 1 and 2 yr F/U were correlated. Pre-operative stages of moyamoya disease were Suzuki type 1 in 1, 2 in 6, 3 in 7, and 4 in 9 cases. Mean PIs of each territory were summarized in the table. PIs of operated (MCA and ACA) territories were improved in 14, unchanged in 7, and aggravated in 2 cases at 1 yr F/U. PIs of PCA territory were improved in 4, unchanged in 16, and aggravated in 3 cases. At 2 yr F/U, PIs of operated territories were unchanged in 10 and improved in 12 cases including 2 with aggravation and 5 with no change at 1 yr F/U, but newly aggravated in 2 cases. Pis of PCA territory were improved in 5 or unchanged in 15, but further or newly aggravated in 3 cases. The arterial stenosis was progressed in 9 cases (5 MCA, 3 PCA, and/or 3 ACA). In these cases, PIs were aggravated in 3(2 operated and/or 2 PCA territories) with poor collateral formation, unchanged in 2, and improved in 4 cases during 2 yr F/U. Cerebral perfusion of MCA and ACA territories progressively improved during 2 yr F/U, even in cases aggravated or not improved at 1 yr after EDAMS p<0.05 (perop, vs 1 yr), p<0.05 ( 1 yr vs 2 yr), not significant

[en] Diuretic renography (DR) can be false negative with upper urinary tract obstruction due to low compliance of the renal pelvis. Delayed parenchymal transit (DPT) may be a valuable sign in case of false negative DR. We compared the diagnostic values of DR and DPT during Tc-99m MAG3 diuretic scan in adults with suspected unilateral obstructive uropathy. Fifty-four patients (male:female=30:24, age: 40.7±15.5 yrs) who underwent Tc-99m MAG3 diuretic scan due to suspicious unilateral obstructive uropathy were analyzed. DR with a T_1/2 of > 15 min was considered as positive for obstruction. DPT was considered to be present when there was delayed appearance of radioactivity in the renal pelvis and prolonged retention of radioactivity in the renal pelvis and prolonged retention of radioactivity in the renal parenchyma. The renal area ratio was defined as the ratio of pixel number of hydronephrotic after intervention, or aggravated hydronephrosis without intervention. Non-obstruction was defined as unchanged hydronephrosis over 6 months. Twenty-six renal units had obstruction and 28 no obstruction. The sensitivities of DR and DPT were 69% (18/26) and 50% (13/26) respectively. Two renal units with DPT but negative DR showed DPT had lower renal area ratio than 7 renal units without DPT (0.97±0.20 vs 1.30±0.41, p<0.05). Differential renal function was not significantly different between these groups. DPT correctly diagnosed all renal units with non-obstruction (specificity 100%), while the specificity of DR was 89% (25/28). DPT during Tc-99m MAG3 diuretic scan may be a valuable sign in diagnosing urinary obstruction especially in patients with false negative DR and early HN

[en] We describe here the synthesis of ^99mTc-ciprofloxacin by four different methods and its biodistribution. All of the methods gave high radiochemical yields of ≥90% and high stability of ≥90% at 6 h after preparation. However HPLC analysis, bacterial binding assay, and in vivo distribution for the four ^99mTc-ciprofloxacins showed different results. Among these methods, the use of formamidine sulfinic acid with microwave heating (Method A) was fast and easy, and gave more desirable biological properties than the other methods