뇌와 뇌간의 모든 기능이 정지되어 인공적으로 심폐 기능은 유지되고 있더라도 뇌의 혈액순환은 중지되고 전체 뇌에 경색이 있어 회복이 불가능한 상태를 뇌사라 한다. 이렇게 뇌와 뇌간의 모든 기능이 정지된 이후에는 곧 심장 정지가 뒤따른다. 심장과 폐의 기능 정지에 의해 죽음을 정의하는 것은 심폐소생 장치 및 생명유지 장치의 효과적인 발달로 이제는 뇌자체의 기능을 평가하는 것으로 대치되게 되었다. 최근 장기 이식술의 발달로 혈액순환을 비롯한 식물적인 기능은 인공적으로 유지되는 상태에서 가능한한 빠른시간내에 적용할 수 있는 뇌사판정 방법의 필요성이 대두되었다. 그래서 이러한 판정을 하는데 소요되는 시간을 줄이기 위한 뇌사를 확신할 수 있는 여러가지 진단 방법에 대한 관심이 고조되었다. 동위원소 뇌혈관촬영술도 이런 진단방법중 하나로 뇌혈액순환의 정지를 보여줌으로써 임상적으로 뇌사를 진단하는 데 보조적인 방법으로 사용될 수 있다.

Patterns of abnormality in regional cerebral perfusion and its relation to clinical severity was evaluated with 32 head injury patients using $^{99m}Tc-HMPAO$ single photon emission tomography (SPECT). The findings were compared with computed tomography (CT) done within 48 hours of each SPECT study. The initial SPECT study was done within 7 days of injury in 16 cases, between 1 week and 2 months in 12, and after over 2 months in 4. Nineteen of the patients underwent followup SPECT and CT after a mean interval of 1 to 2 months. The initial SPECT showed abnormalities in 96% (31/32) of the patients while CT showed abnormal findings in only 81% (26/32). There were a total of 54 supratentorial SPECT lesions in all. Ninity percent (49/54) of these were of regional hypoperfusion, while 5 lesions showed focal hyperperfusion. The lesions were most often localized in the frontal and temporal lobes. Fifty five percent (30/54) were areas not detected as a lesion on CT. Cerebellar diaschisis was observed in 50% (16/32) of the patients. The degree of perfusion abnormality was quantified by the product of differential activity and a size factor. Correlation between the degree of perfusion abnormality and the clinical severity (Glasgow coma scale) failed to show statistical significance (p=0.053). The amount of change in the degree of perfusion abnormality on follow up SPECT was compared to the amount of change in clinical severity. Perfusion abnormality showed a tendancy to improve in most patients, and the degree of improvement showed significant correlation with the amount of clinical improvement (p < 0.01).

Both interictal and ictal $^{99m}Tc-HMPAO$ brain SPECT were performed in 22 patients with medically intractable epilepsy. Localization of epileptic foci in our patients was made by combined results of EEG and other tests, including Wada test, magnetic resonance imaging, and neuropsychometric test. Among them, ictal $^{99m}Tc-HMPAO$ SPECT, localized epilptic foci in 20 of 22 patients and provided evidence of epileptic focus in 12 patients by demonstrating maximally increased regional cerebral perfusion (rCP) in epileptic foci during the ictal study with decreased rCP in interictal study. Ictal $^{99m}Tc-HMPAO$ SPECT was particularly useful for investigating epileptic foci, and when correlated with simultaneously recorded ictal EEG, provided further insight for localizing epileptic foci. Conclusively, $^{99m}Tc-HMPAO$ SPECT is. a useful, noninvasive method of localizing epileptic activity which may be particularly important for presurgical investigations, especially in those patients without large morphological lesions.

Regional cerebral blood flow were measured in 10 patients with Parkinson's disease and 12 normal persons using $^{99m}Tc-HMPAO$ SPECT. Reconstructed images were interpreted qualitatively and were compared with those findings of CT. For the quantitative analysis, six pairs of region of interest matched with the perfusion territories of large cerebral arteries and cerebellar hemisphere were determined. From the count values, indices showing the degree of asymmetry between right and left cerebral or cerebellar hemisphere, cerebral asymmetry index (ASI) and percent index of cerebellar asymmetry (PIA), and an index showing change of each region, region to cerebellum ratio (RCR) were obtained. ASI of normal persons and patients were $0.082{\pm}0.033$ and $0.108{\pm}0.062$, respectively and PIA were $-0.4{\pm}0.7%$ and $-0.7{\pm}1.0%$, respectively, which showed no statistically significant difference between normal persons and patients. Among 10 RCR's, those of both regions of basal ganglia and both regions of anterior cerebral artery were significantly reduced. We concluded that the most significant reduction of regional cerebral blood flow in patients with Parkinson's disease was observed in the regions of basal ganglia and in the regions of anterior cerebral artery, and the degree of change in hemispheric blood flow was similar in both hemisphere.

Diagnostic approaches such as angiography, ultrasound, computed tomography and nuclear magnetic resonance have limitation for contributing to the early clinical diagnosis of atherosclerosis. Recently, $^{99m}Tc-labelled$ low density lipoprotein was developed to detect early atherosclerotic lesion by external imaging with gamma camera. To determine whether $^{99m}Tc-LDL$ scintigraphy can visualize the active atherosclerotic lesion, rabbits were injected with $^{99m}Tc-LDL$, 3 months after feeding dietary fat (lanolin) and we obtained following results. 1) Labelling efficiency of $^{99m}Tc-LDL$ was $79\sim88%$. 2) Biodistribution study of normal rabbits with $^{99m}Tc-LDL$ revealed the high activities in spleen, adrenal gland, liver, kidney which are major organs of high metabolic rate of LDL. 3) Three months after feeding lanolin, serum cholesterol was markedly increased from $74{\pm}17mg/dl$ to $979{\pm}153mg/dl$ and histologic study of aorta after sacrificing the rabbit demonstrated marked atherosclerotic changes. 4) Atherosclerotic lesion of abdominal aorta which was confirmed with histologic study could be demonstrated in $^{99m}Tc-LDL$ scintigraphy after feeding lanolin for 3 months. In conclusion, the results of this preliminary investigation suggest that it may be possible to image active atheromatous lesion with $^{99m}Tc-LDL$. It is anticipated that this promising agent may allow the in vivo monitoring of preclinical atherosclerotic lesions and may be useful to evaluate the metabolic pathway of LDL in humans.

Rest gated blood pool scan (Rest GBP scan) and dipyridamole $^{99m}Tc-MIBI$ SPECT were Performed in 34 patients with or suspected coronary artery disease. Both studies were performed within $2\sim32$ days (mean 8.1 days). A significant correlation was present between left ventricular ejection fraction (r= -0.7356, p<0.001) and peak ejection rate and peak filling rate in rest GBP scan and perfusion defect in MIBI SPECT. And there were acceptable correlations (0.05$26.2{\pm}10.8%$, severe hypokinesia, akinesia or dyskinesia in 16 regions: $78.2{\pm}23.7$, p<0.001). These data indicate there is a significant coupling between the degree of myocardial perfusion and the myocardial functional change in coronary artery disease.

Clinical role of $^{99m}Tc-MIBI$ myocardial scintigraphy in the diagnosis of coronary artery disease (CAD) is now well accepted, however, the role of it in the identification of viable myocardium in patients with chronic CAD has not yet been clarified. To determine the usefulness of rest-injected $^{99m}Tc-MIBI$ scan as a marker of myocardial viability, the regional uptake of this agent at rest was compared with that of $^{201}Tl$ on reinjection and 24 hours after reinjection images. Subject patients were 13 chronic CAD patients who showed irreversible perfusion defect(s) on standard pharmacologic (dipyridamole) stress-redistribution images. Immediately after the redistribution images were obtained, 37 MBq thallium was injected at rest, and images were reacquired at 10 minutes and 24 hours after reinjection. After then 740 MBq $^{99m}Tc-MIBI$ was injected, and 1 hour later rest MIBI myocardial imaging was performed. Five sets of imagestress, redistribution, reinjection, delayed images of thallium, and rest image of MIBI) were then analyzed qualitatively and quantitatively. Left ventricle was arbitrarily divided into 9 segments (apex, basal and apical portions of anterior, septal, inferior, and lateral walls). Seven patients and 30 regions showed a fixed perfusion defect on the stress-redistribution images. Among 30 regions, 15 showed positive uptakes and 6 showed negative uptakes on both $^{201}Tl$ reinjection/delayed images and $^{99m}Tc-MIBI$ rest images. Five regions showed only thallium uptake and were regarded as viable clinically. Of four regions which showed only $^{99m}Tc-MIBI$ uptake, two were regarded as viable, while the other two were regarded as a nonviable scar tissue clinically. In conclusion, $^{201}Tl$ reinjection technique was more reliable in the identification of viable myocardium. However, the role of $^{99m}Tc-MIBI$ in identification of viable myocardium was still remained to be clarified because 2 of 9 regions showed only $^{99m}Tc-MIBI$ uptake and were regarded as viable tissues.

The 20-minute $^{99m}Tc-pertechnetate$ uptake became readily available for routine use and it replaced $^{131}I$ for thyroid imaging. However measuring thyroid uptake during a 5-minute minimizes pertechnetate uptake by the salivary glands and presence of contaminated saliva from those glands in to the pharynx and esophagus. A study was carried out to determine the suitability of the utility of a S-minute and 20-minute interval from administration of $^{99m}Tc-pertechnetate$ to imaging and uptake measurement as a replacement for the 24 hour standard originally established with $^{131}I$, and to evaluate the relationship between 5-minute $^{99m}Tc-pertechnetate$ uptake and other thyroid functions. A 5-minute and 20-minute uptake of $^{99m}Tc-pertechnetate$ were measured in 70 patients with thyroid disease at Yeungnam University Hospital from March 1, 1991 to Feb. 29, 1992. The results were as follows. 1) The 5-minute $^{99m}Tc-pertechnetate$ uptake in Graves' disease, Hashimoto's thyroiditis, simple goiter, non toxic nodular goiter, subacute thyroiditis and euthyroid were 18.2%, 14.6%, 2.8%, 3.2%, 1.2% and 1.1%, respectively. There was a significant difference between the mean of the euthyroid group and the mean of the Graves' disease. So differenciation between them can be easily made. 2) The 5 minute $^{99m}Tc-pertechnetate$ thyroid uptake was well correlated with 24 hour $^{131}I$ thyroid uptake (r=0.75, p<0.001). These data provided an equation for estimating the 24 hour uptake of iodide given the 5 minute pertechnetate uptake: Estimated 24-hour $^{131}I$ thyroid Uptake= 7.188*ln (5 minute $^{99m}Tc-pertechnetate$ uptake)+16.94 3) The 20-minute $^{99m}Tc-pertechnetate$ thyroid uptake was well correlated with 24-hour $^{131}I$ uptake (r=0.72, p<0.001) and 5-minute $^{99m}Tc-pertechnetate$ thyroid uptake (r=0.96, p<0.001). 4) In the Graves' disease, The 5-minute $^{99m}Tc-pertechnetate$ thyroid uptake was well correlated with serum $T_3-resin$ uptake (r=0.46, p<0.01), serum total $T_3$ (r=0.55, p<0.05), serum total $T_4$ (r=0.46, p<0.05). These results suggest that 5-minute ${99m}Tc-pertechnetate$ thyroid uptake has been found at least as useful as 24-hour $^{131}I$ uptake for diagnostic confirmation at our hospital, the logistical advantages of completing the diagnosis. The exam in 5-minutes led us to abandon the 24-hour study in the majority of patients, but the 24-hour $^{131}I$ uptake is still obtained in patients with planned or potential radioiodine therapy.

Although early diagnosis of urinary tract infection is important, the radiologic evaluation is still controversial because of the low sensitivity and the lack of cost-effectiveness. This study was carried out to evaluate the clinical utility of high resolution triple head $^{99m}Tc-DMSA$ SPECT imaging in urinary tract infection. We prospectively performed $^{99m}Tc-DMSA$ planar and SPECT imaging, ultrasound of kidney (US), intravenous pyelography (IVP) and voiding cystourethrography (VCU) in all 60 adult patients with UTI [26 with first episode of acute pyelonephritis (APN), 22 with recurrent APN, and 12 persistent asymptomatic pyuria] and 25 normal persons. To assess reversibility of the renal cortical defect (RCD), $^{99m}Tc-DMSA$ SPECT was repeated 1 to 8 months later in those patients with abnormal initial findings. Overall detection rate of $^{99m}Tc-DMSA$ SPECT imaging was 83% (50/60), but planar, US, IVP and VCU showed abnormal findings in 68%, 28%, 32% and 13%, respectively. 25 out of 27 patients with normal or single RCD were all normal in other radioligic studies. Only two patients showed vesicoureteral reflux (VUR) on VCU (grade I) and mild hydronephrosis on IVP. But, high proportion of those with multiple RCD showed abnormal findings on US (17/33), IVP (18/33), and VCU (7/33): 67% in any of these 3 studies. Especially, 3 out 7 patients with VUR showed multiple RCD on $^{99m}Tc-DMSA$ SPECT without any abnormality on IVP or US. 25 normal persons showed normal findings in all studies except one false positive finding on $^{99m}Tc-DMSA$ SPECT imaging. Follow-up $^{99m}Tc-DMSA$ SPECT was done in 28 patients (13 with single RCD, 15 with multiple RCD). All 13 patients with single RCD showed improvement. Those with multiple RCD presented improvement in 4, no change in 10, and aggravation in 1 on follow-up studies. With these results, we conclude: 1) $^{99m}Tc-DMSA$ SPECT imaging is superior to planar imaging, US, IVP or VCU in detection of renal lesion in urinary tract infection. $^{99m}Tc-DMSA$ SPECT is useful as a initial diagnostic tool in adult patients with urinary tract infection. 2) The multiple RCD on $^{99m}Tc-DMSA$ SPECT represent the high probability of irreversible tissue change and need of extensive urological work-up.

당뇨병 환자에서 $^{99m}Tc-colloid$ labeled scrambled egg와 hamberger를 이용한 고형식의 위배출 양상의 변화를 동위원소를 이용하여 고찰한 결과 당뇨병성 신경증의 정도, 특히 자율신경계 침습 유무, 이환기간 및 망막증의 정도와 관련이 있었고 혈당농도 및 조절상태와는 무관한 것으로 나타나 당뇨병 환자에서 신경장애가 심할수록 이환기간이 길수록 위장운동 장애가 심한 것을 나타내있다. 당뇨병성 위마비증도 자율신경계 침습이 있는 경우에 잘 발생하였고 Cisapride는 당뇨병 환자의 위 배출시간 및 위저류율을 호전시켰다. $^{99m}Tc-colloid$ labeled scrambled egg와 hamberger를 이용한 고형식의 핵의학적 정사 방법은 barium을 이용한 방사선학적 청사보다 정량화하기 쉽고 생리 식염수 부하검사보다 비침습적이며 당뇨병 환자의 실재 일회 식사량과 비슷한 500kCal의 열량으로 임상상을 잘 반영한다고 사료된다.

Anorexia, nausea, and vomiting are one of the most frequent symptoms in viral hepatits patients. These may be due to poorly detoxified substances by dysfunctioned hepatocytes or by gastritis, but the pathophysiology is not totally understood. The symptoms interfere with adequate nutrient intake and are managed by metoclopramide, which accelerates gastric emptying. Thus delayed gastric emptying may well be a contributing factor to such symptoms. To determine such a relationship, we measured gastric emptying time in 11 normal subjects,9 acute (AVH), and 12 chronic B viral hepatitis (CVH) patients. All were males with a mean age of 23 years. An egg was labeled with 0.5 mCi of $^{99m}Tc-sulfur$ colloid, fried, then eaten between 2 slices of bread with 100 cc of water. Anterior and posterior images were taken at 20 minute intervals over a 2 hour period. A geometric mean of activity pertaining to the gastric region was measured, and $T_{1/2}$ was calculated from the time activity curve. $T_{1/2}$ for normal the group was $57.8{\pm}6.3$ minutes while that for the AVH and CVH group was $58.2{\pm}8.2$ (p=0.40) and $64.1{\pm}10.5$ (p=0.09), respectively. There was 1 AVH Patient and 4 CVH patients with prolonged $T_{1/2}$. Anorexia and nausea was seen in 71% and 46% of the patients, respectively. 80% and 60% of the patients with prolonged $T_{1/2}$ had anorexia and nausea, respectively.

To evaluate the sensitivity and specificity of captopril renal scan for renovascular hypertension, we employed the captopril renal scan in conjunction with renal angiography in 81 patients, 159 kidneys, who were referred to evaluate the cause of hypertension. We defined the renovascular hypertension by the criteria of demonstration of renal artery stenosis by angiography, and improvement or cure of hypertension by revascularization. Visual and quantitative evaluation of $^{99m}Tc-DTPA$ renal scan was peformed pre and post captopril administration. The prevalence rate of renovascular hypertension was 40% in comparing with renal angiography, and 70% in confirmed cases. The causes of renovascular hypertension in 81 patients were Takayasu's arteritis, fibromuscular dysplasia, atherosclerosis, essential hypertension, chronic pyetonephritis etc. The sensitivity and specificity of captopril renal scan in comparing with renal angiography were 80%, 86.5%, respectively and also 84.2%, 72.6% in confirmed cases of renovascular hypertension, respectively. The causes of false negative cases were nonfunctioning kidney due to complete obstruction or long duration of disease in basal scan, segmental branch artery stenosis, unknown causes, and suspicious true negative cases without confirmation. The false positive cases were abdominal aortic stenosis or aneurysm, dehydration, unknown causes, and suspicious true positive cases. We conclude that captopril renal scintigraphy is highly sensitive, reasonably specific diagnostic method and comparable to other techniques very favorably.

Ga-67 citrate scan has been requested for detection or follow-up of inflammatory or neoplastic disease. Visualization of Ga-67 citrate in the kidneys at 48 and 72 hr post injection is usually interpreted as evidence of renal pathology. But precise mechanisms of abnormal Ga-67 uptake in kidneys were unknown. We undertook a study to determine the clinical value of Ga-67 citrate imaging of the kidneys in 68 patients with primary or secondary nephropathy confirmed by renal biopsy and 66 control patients without renal disease. Renal uptake in 48 to 72 hr images was graded as follows: Grade 0=back-ground activity:1=faint uptake greater than background;2=definite uptake, but less than lumbar vertebrae; 3=same uptake as lumbar vertebrae, but less than liver; 4=same or higher uptake than liver. The results were as follows. 1) 42 of 65 (62%) patients with noninfectious nephritis showed grade 2 or higher Ga-67 renal uptake but only 10 percent of control patients showed similar uptake. 2) In 14 patients with systemic lupus erythematosus, 8 of 9 (89%) patients with lupus nephritis exhibited marked renal uptake 3) 36 of 41 patients (88%) with combined nephrotic syndrome showed Grade 2 or higher renal uptake. 4) Renal Ga-67 uptake was correlated with clinical severity of nephrotic syndrome determined by serum albumin level, 24 hr urine protein excretion and serum lipid levels. 5) After complete remission of nephrotic syndrome, renal uptake in all 8 patients who were initially Grade 3 or 4, decreased to Grade 1 or 0. In conclusion, we think that the mechanism of renal Ga-67 uptake in nephrotic syndrome might be related to the pathogenesis of nephrotic syndrome. In systemic lupus erythematosus, Ga-67 citrate scan is useful in predicting renal involvement.

$^{99m}Tc-dimercaptosuccinic$ acid (DMSA) 주사후 일정시간에 측정한 절대적 신섭취량은 기능이 살아있는 신피질량과 관계있다. 소아의 신기능은 출생후 계속 성숙되어 생후 약 $1\sim2$년에 성인의 기능에 도달하는데 DMSA섭취도 성인과는 다른 양상을 보일 것으로 기대되며 신질환에서 절대적 신섭취율의 평가는 연령을 고려해야 할 것이다. 저자들은 DMSA 스캔을 시행한 소아 환자를 대상으로 스캔상 피질 결손이 없으며 양측신의 섭취율이 비슷하고 혈중 크레아티닌치가 정상인 경우를 대조군으로 하여 연령별 DMSA의 절대적 신섭취율을 구하였고 방광요관역류를 가진 환아를 대상으로 DMSA스캔을 시행하고 신섭취율을 조사하였다. 1) 대조군은 모두 65명으로 좌우측 신섭취율의 유의한 차이는 없었으며 연령에 따라 2세경에 플라토에 도달하였는데 한쪽 신장의 평균섭취율은 3개월 미만이 $14.5{\pm}3.1%$ ID, 3개월에서 6개월 미만이 $17.2{\pm}2.1%$ID, 6개월에서 1년 미만이 $18.4{\pm}1.3%$ID, 1년에서 1년6개월 미만이 $19.3{\pm}1.1%$ID, 1년 6개월에서 2년 미만이 $21.9{\pm}2.0%$ID, 2세이상 15세이하가 $20.1{\pm}0.6%$ID였으며 전체 평균섭취율은 $19.4{\pm}0.5%$ID (injected dose, $mean{\pm}S.E.$)였다. 2) 방광요관역류를 가진 환아는 55명 (일측성 56명, 양측성 29명)으로 109신장을 대상으로 하였다. 방광요관역류의 정도와 피질결손의 수와는 대체로 비례관계가 있었으나 방광요관역류가 없으면서 피질결손이 있는 경우가 25신장중 2예 (8%)였으며, 방광요관역류가 있는 84신장중 27예 (32.1%), 이중에서 방광요관역류가 3도 이상인 62신장중 13예 (21%)에서는 피질결손이 없었다. 3) 이환신의 DMSA 섭취율을 연령에 따른 대조군의 섭취율에 대한 비(섭취율비)로 나타내면 한쪽에 역류가 있을 때 이환신의 경우 $0.55{\pm}0.06$, 정상신의 경우 $1.34{\pm}0.05$이었으며, 양쪽에 역류가 있을 때는 평균 $0.82{\pm}0.08$ $(mean{\pm}S.E.)$ 이었다. 4) 피질결손이 있는 신장의 절대 DMSA 신섭취율은 감소되어 있었고 상대측 신장의 섭취율은 피질 결손이 있더라도 대상적인 증가의 경향을 보였다. 이상의 결과로 소아에서 DMSA 절대적 신섭취율의 연령에 따른 변화를 알 수 있었으며 방광요관역류의 정도와 피질결손의 정도가 반드시 비례하지만은 않아서 시간경과에 따른 추후 검사가 필요하리라 생각된다. 또한 방광요관역류가 있는 환아에서 DMSA 섭취율로 신기능을 평가할 때, 특히 영유아에서 연령에 따른 고려가 있어야 할 것으로 보인다.

In order to establish the clinical significance of pubic bone uptake of radionuclide on $^{99m}Tc-MDP$ bone scintigraphs, we analyzed uptake patterns of normal adult pubic bone in 300 randomly sampled subjects. Bone scintigraphy was performed in each patient for the reasons other than pubic or pelvic problems. One-hundred-fifty-four were men and 146 women. The age ranged from 8 to 78 years. The pubic uptake was graded arbitrarily into 4 grades by comparing the pubic uptake density with that of L5 vertebra. Thus, grade I was defined as the L5 density greater than the pubic density, grade II as the L5 density equals to the pubic density, grade III as the L5 density less than the pubic cdensity, and grade IV as the L5 density much less than the pubic density. Statistical analysis revealed negative trend in the pubic uptake from grade IV to grade I with age. There was no sexual difference in the pubic uptake. The women in the 3rd and 4th decades disclosed higher pubic uptake (grades III, IV) probably due to pregnancy and labor.

We evaluated the scintigraphic findings of sonographically atypical hemangioma, that is, a hypoechoic or heterogeneously hypoechoic nodule which contains hypoechoic areas more than 40% of the volume, and compared it with those of sonographically typical hemangioma in 26 patients with 31 nodules. Sonographically atypical hemangioma were 13 in 11 patients and sonographically typical hemangioma were 18 the 15 patients. Dynamic blood flow, planar and SPECT blood pool imaging was performed. In atypical hemangioma, increased blood pool activity was seen in 11 of 13 nodules on SPECT and in 10 of 13 nodules on planar image and increased blood flow was seen in 4 of 13 nodules on dynamic blood flow study. No significant difference in detecting increased blood pool activity between sonographically atypical and typical hemangioma. In conclusion, $^{99m}Tc-red$ blood cell SPECT is as useful in diagnosis of sonographically atypical hemangioma as in typical hemangioma and can be used as a confirmatory or complementary study.

서울대학교 의과대학에서 개발한 항 CEA항체에 대한 방사성옥소 및 $^{99m}Tc$의 표지법을 개발하고 이런 표지항체의 면역학적 특성을 분석하였다. 1) 8가지의 항 CEA의 단세포군 항체중 CEA-79항체와 CEA-92항체가 가장 좋은 면역학적 특성을 보였다. 표지항체의 면역반응성은 60% 정도이었고, 항원/항체 친화상수는 $1\sim2\times10^9l/m$ 이었다. 2) CEA-79항체는 chloramine-T법으로, CEA-92항체는 iodogen 법으로 방사성옥소를 표지 하는 것이 가장 좋은 표지효율 및 면역 반응성을 보였다. 3) CEA-79항체는 0.5 mCi/mg에서부터 100mCi/mg까지 비방사능을 변화시켰을 때 표지효율이나 면역 반응성에 유의한 차이는 발견할 수 없었다. 4) Glucarate를 이용한 pretargeting transchelation법으로 CEA-79항체를 $^{99m}Tc$로 표지하는 조건을 확립하였다. 표지효율은 $60\sim70%$ 이었다. 본 실험을 통하여 얻은 적절한 조건의 $^{131}I$과 $^{99m}Tc$표지방법의 확립은 앞으로 방사면역신티그라피와 방사면역치료법에 유용하게 사용될 수 있을 것으로 기대된다.

The $^{67}Ga$ has somewhat long physical and biological half livies with 78 hours and 600 hours respectively, so we can get $^{67}Ga-scan$ images for 3 or more days after once injection of $^{67}Ga$. Furthermore $^{67}Ga$ scan would be useful to search some residual tumors after surgical removal of the tumors trapped with $^{67}Ga$. However $^{67}Ga$ bound with plasma proteins would be delayed in plasma clearance as approximately 10% of the dose remains in the plasma at 24 hours. If the remained $^{67}Ga$ in the plasma is redistributed into the surgical wound, we wouldn't evaluate the degree of the tumor remained after surgery. So the authors examined the amounts of the remained blood $^{67}Ga$ and the redistribution of the blood $^{67}Ga$ into the artificial wound with S or more centimeters in the diameter at the neck and chest of the rabbits. The results were as follows; 1) The $^{67}Ga$ remained in the plasma were 12%, 5.7%, 4.2% at 24, 48 and 72 hours after $^{67}Ga$ injection respectively. 2) The blood $^{67}Ga$ were redistributed into the artificial wound with 5.9% at 48 hours and 6.9% at 72 hours after $^{67}Ga$ injection.

Treatment for the brain tumors consist of surgery, chemotherapy, and a variety of methods of irradiation. Therapy is aimed to destroy the tumor, but necrosis and edema occur concurrently. Conventional structural imaging techniques such as CT or MRI are unable to reliably distinguish persistent and recurrent tumor from necrosis or edema. T1-201 has been shown to be useful in the evaluation of the myocardial viability by comparing the early uptake and redistribution image. The aim of this study is to evaluate the clinical usefulness of the early uptake and delayed washout images of the T1-201 brain SPECT in the brain tumors. In the pathologically diagnosed various brain tumor patients, brain SPECT was done with rotating gamma camera 15 minutes and 3 hours after T1-201 injection, and the T1-201 uptake in the tumor was compared with the skull and scalp activity. In the glioblastoma multiforme, meningioma and metastatic tumor, the T1-201 uptake was higher than low grade glioma in both 15 minute and 3 hour images (p<0.02). In the low grade glioma,3 hour T1-201 uptake was significantly lower than 15 minute uptake (p<0.05) but in the glioblastoma, meningioma and metastatic tumor there was no significant difference. There was no significant difference in the T1-201 uptake among the glioblastoma, meningioma and metastatic tumors. In one matastatic tumor, T1-201 uptake was decreased after radiation therapy. T1-201 brain SPECT could distinguish the benign and malignancy, and seems to be useful in the follow-up after treatment. But one of the early or delayed SPECT seems not to be necessary for these purposes.

Pheochromocytomas are catecholamine producing tumors of neuroectoderrnal origin. Diagnosis of pheochromocytoma is significant due to potentially curable hypertension. But they have a significant associated morbidity due to uncontrolled hypertension and mortality since 10% are malignant. From Aug. 1989 to Jul. 1992, 12 patients of our institution had $^{131}I-MIBG$ scan during work up of suspected primary or recurrent pheochromocytoma. In our studies conclude that $^{131}I-MIBG$ scan is recommended as the initial localizing study of choice (especially for the detection of extraadrenal disease and postoperative recurrence) as a guide for CT and/or MR and specific functional confirmation of their findings.

악성종양의 진단 및 치료에 있어서 특정 종양에 대한 항체를 이용하는 연구가 활발히 진행되고 있다. 단세포군항체를 이용한 방사면역신티그라피로 암의 조기 진단 및 영상화가 가능하고 나아가 방사면역치료는 암의 선택적 치료에 도움이 될 수 있다. 위암은 우리나라에서 가장 흔한 악성종양으로 방사면역신티그라피와 방사면역치료법이 새로운 방법으로 모색되고 있다. 이러한 진단 및 치료법의 성공여부를 결정하는 중요한 인자의 하나가 종양조직내에서 종양관련 항원의 농도와 분포이다. 따라서 본 연구에서는 단세포군 항체를 이용한 방사면역학적 방법의 임상 이용을 위한 기초 연구의 일환으로 in vitro quantitative autoradiography를 이용하여 종양 관련항원인 TAG-72와 CEA의 위암조직내 농도 및 분포를 측정하였다. 33예의 위암조직에서 얻은 동결절편을 $1.3\sim83.3$ nmol/liter의 $^{125}I$ 표지 항 TAG-72 단세포군 항체 B-72.3과 항 CEA 단세포군 항체 CEA-79로 반응시킨 후 이 표본들의 자가방사법 디지탈 영상을 H & E 염색과 immunoperoxidase염색 표본과 비교하였으며, 특정 단세포군 항체의 결합에 대한 컴퓨터 분석으로 조직내 항원의 농도와 분포를 측정하였다. TAG-72는 25예(75.7%)의 조직에서 검출되었으며 그 농도는 $8.4\sim525.3$ pmol/gram이었고, CEA는 32예 (96.9%)에서 검출되었으며 그 농도는 $8.8\sim592.9$ pmol/gram 이었다. CEA의 위암 조직내 발현농도는 중앙치가 101.7 pmol/gram 으로 TAG-72의 중앙치인 27.9 pmol/gram 보다 높았다. TAG-72의 조직내 분포는 41.4%에서 병변 부위의 암세포 분포와 일치하였고, CEA의 분포는 병변 부위의 80.5%에서 암세포와 일치하는 소견을 나타내었다. TAG-72의 농도는 점액성 선종(mucinous adenocarcinoma)과 점액함유 선종(mucin containing adenocarcinoma)에서 다른 선종보다 더 높았다. CEA의 농도는 위암의 병리학적 종류에 따른 유의한 차이가 없었다. 이상의 결과로 위암조직에서 TAG-72와 CEA항원이 다양하게 발현됨을 알 수 있었고 CEA는 TAG-72 보다 더 빈번하게 균일한 분포로 발현하는 것으로 나타났다.

This study was designed to evaluate a direct method of $^{99m}Tc$ labeling using $\beta-mercaptoethanol$ as a reducing agent, and to investigate whether $^{99m}Tc$ labeled specific monoclonal antibody against carcinoembryonic antigen (CEA-92) can be used for the scintigraphic localization of human colon cancer xenograft. Purified CEA-92 IgG was fragmented into F $(ab')_2$ and then labeled with $^{99m}Tc$ by transchelation method using glucarate as a chelator. Labeling efficiency, immunological reactivity and in vitro stability of $^{99m}Tc$ CEA-92 F $(ab')_2$ were measured and then injected intravenously into nude mice bearing human colon cancer (SNU-C4). Scintigrams were obtained at 24 hour after injection. Then nude mice were sacrificed and the radioactivity was measured Labeling efficiency of injected $^{99m}Tc$ CEA-92 F $(ab')_2$, immunoreative fraction and in vitro stability at 24 hour of injected $^{99m}Tc$ CEA-92 F $(ab')_2$ was 45.2%, 32.8% and 57.4%, respectively. At 24 hour after injection, % ID/g in kidney (46.77) showed high uptake, but %ID/g in tumor (1.65) was significantly higher than spleen (0.69), muscle (0.16), intestine (0.45), stomach (0.75), heart (0.48) and blood (0.45). There was no significant difference between tumor and liver (1.81). Tumor contrast as quantitated by tumor to blood ratio of $^{99m}Tc$ CEA-92 F $(ab')_2$ was increased significantly (p<0.005) until 24 hours (3.70), and there was no statistical differece from tumor to blood ratio of I-131 CEA-92 F $(ab')_2$. The scintigram demonstrated localization of radioactivity over transplanted tumor, but significant background radioactivity was also noted over kidney and abdomen. It is concluded that CEA-92 F $(ab')_2$ can be labeled with $^{99m}Tc$ by a direct transchelation method using $\beta-mercaptoethanol$ as a reducing agent and $^{99m}Tc$ labeled CEA-92 F $(ab')_2$ can be used for the scintigraphic localization of human colon cancer xenograft in nude mice model.

Hepatic hydrothorax is defined as the presence, in a cirrhotic patient, of a large pleural effusion in the absence of primary pulmonary or cardiac disease. Pleural effusions occur in 5% to 10% of patients with cirrhosis of the liver. The effusions are usually right-sided, but may be bilateral or left-sided. The precise mechanism of fluid accumulation is not clear. We reported a case of right hepatic hydrothorax occuring in the liver cirrhosis with ascites. Diagnosis was confirmed by the intraperitoneal and intrapleural injection of radioisotope $^{99m}Tc-tin$ colloid that demonstrated the one-way transdiaphragmatic flow of fluid from the peritoneal to pleural cavities.