Ⅲ. MATERIAL AND METHODS

1. roi0 roi1 간 / 신 장 섭 취 비 율 조제 후 주사시간 정적신장검사 시 99mTc-DMSA(dimercaptosuccinic acid) 표지 후 주사시간에따른 간/신장의섭취비율변화 연세의료원세브란스병원핵의학과 이한울ㆍ박훈희ㆍ김정열ㆍ강천구ㆍ최영숙ㆍ임한상ㆍ김재삼ㆍ이창호 Ⅰ. ABSTRACT Purpose 99mTc-DMSA (dimercaptosuccinic acid) that is used for static renal scintigraphy is a radiopharmaceutical product to get very good images of renal cortex. About 40-50% of the injected amount of 99mTc-DMSA is taken up by the kidney cortex, and less than 3% of the injected amount is taken up by the liver. However, when exposed to the air, 99mTc-DMSA reacts with oxygen, resulting in a decrease in the kidney uptake and increase in the liver uptake. In this study, we are intended to find out the change in the rates of liver/kidney uptake depending on the time of injection after the product labeling for static renal scintigraphy. Materials and Methods Children under the age of seven (mean age 2.5 ± 2.1 years old), 31 patients (male: 17, female: 14) were studied. After verifying the time of labeling 99mTc-DMSA and the time of injection after labeling (56 ± 42 min), we performed the examinations in average 206 ± 21 min after injection, obtaining the images using the equipment INFINIA (General Electric Healthcare, Wisconsin, MI, USA). We measured the average uptake (Average Count) by setting the region of interests (ROIs) on the anterior image in the liver and the left kidney, respectively, and then we compared the liver/kidney uptake rates. However, we evaluated the patients with both kidneys forming symmetrical size and the uptake rates belonging to the normal range. We used SPSS ver.12 for statistical analysis. Results We analyzed the average uptake of liver/kidney for 31 patients who were examined. The average count rates of liver/kidney depending on the time of injection after labeling were not correlated (r = 0.098), and there was no statistically significant difference (p> 0.05). Conclusion The 99mTc-DMSA measured in 56 ± 42 minutes after the injection in this study did not show any correlation in the changes in liver/kidney uptake. Therefore, if it is used within 4 hours as recommended in the manufacturer's manual, it will not affect the uptake rates of liver/kidney in the obtained images, and it would be able to provide useful clinical information. Fig. 3 The dose for children is adjusted according to body weight. Fig. 4 INFINIA(General Electric Healthcare, Wisconsin, MI, USA) Fig. 5 We measured the Average count in the liver and the left kidney, and then we compared the liver/kidney uptake rates. 영상분석방법 Designed ROIs Anterior Image Liver Avg Count Lt.Kidney Avg Count Fig. 6 ROIs were designed anterior image in liver and right kidney with patients. 획득된영상 중 전면상에서간과간의약품섭취정도에영향을받지않는좌측신장을대상으로각각의관심영역(ROIS; Region Of Interests)을 설정하여평균섭취계수(Avg Count)를 측정하였으며, 간/신장의섭취비율을비교하였다(Fig. 5). 통계 분석 에는 SPSS ver. 12를 이용하였다. Ⅱ. INTRODUCTION 정적신장검사 시 사용되는99mTc-DMSA(dimercaptosuccinic acid)는 매우높은신장피질의섭취로인하여좋은영상을얻을 수 있어서피질의섭취결손을예민하게진단할 수 있으며신장의위치이상이나, 신장내의덩어리를피질기둥(Column OF Bertin)과 구별하기위하여사용되는 방사성의약품이다.1-2)99mTc-DMSA는 약 40 % ~ 50 % 의 주사된양이신장피질내에섭취되며, 약 3 % 이하의주사된양이간에섭취된다. 하지만99mTc-DMSA는 공기와접촉 시 산소와반응하여체내에서의분포가달라져신장섭취가감소하고, 간 섭취가증가한다. 본 연구에서는정적신장검사 시 사용되는99mTc-DMSA 용기와공기의접촉을고려하여약품표지 후 주사시간에따른 간/신장의섭취비율의변화를알아보고자하였다. Ⅳ. RESULTS 총 31개의 획득된 영상에서간/신장의평균섭취계수를분석하였다(Fig. 7). 표지 후 주사시간에따른 간/신장의평균섭취계수비율은일정한상관관계를가지고있지않았고(r = 0.098), 통계적으로유의한차이를보이지않았다(p> 0.05)(Fig. 8). Obtained Image Ⅲ. MATERIAL AND METHODS 환자정보 • Table 1. Characteristics of Patients 양쪽신장의크기가대칭을이루며섭취비율이정상범위(44~56%)에 속하는7세 이하의소아환자31명을 대상으로하였다(Table 1). 30 min after labeling 60 min after labeling 120 min after labeling 180 min after labeling Fig. 7 The images were appeared the change in the rates of liver/kidney uptake depending on the time of injection after the product labeling. Flow Chart 99mTc-DMSA LABELLING INJECTION 3~4 Hrs RESTING IMAGE ACQUISITION Fig. 1. All patients were injected 99mTc-DMSA after verifying the time of labeling 99mTc-DMSA and then scan was performed 3-4 hours later. Fig. 8 The result graph was analyzed the average count rates of liver/kidney depending on the time of injection after labeling. 영상획득방법 방사성의약품은Technetium (99mTc) - succimer(TechneScanDMSA)를 사용하여정적신장검사를시행하였으며소아환자의몸무게에따라투여량을조절하였다(Fig. 2, Fig. 3). 99mTc-DMSA의 표지시간과표지 후 주사시간(56 ± 42분)을 확인하고, 주사 후 평균206 ± 21분에 검사를시행하였으며, 기기는INFINIA (General Electric Healthcare, Wiscon, Mi, USA)를 사용하였고, Matrix는512 x 512이며, 환자를바로눕힌상태에서전면상 과 후면상을각각150만 계수를하여영상을획득하였다(Fig. 4). Ⅴ. CONCLUSION 본 연구에서측정된표지 후 주사시간56 ± 42분에서의 99mTc-DMSA는 간/신장의섭취계수의변화가일정한상관관계를보이지않았다. 그러므로제조업체의메뉴얼에서권장하는표지 후 4시간 이내에약품을사용한다면, 획득영상에서의 간/신장섭취비율에영향을미치지않을것이며, 이는임상적으로유용한정보제공이가능할것으로사료된다. Ⅵ. REFERENCE Fig. 2. 99mTc-succimer was used for static renal scintigraphy. 1. 정준기, 이명철. 고창순핵의학제3판. 고려의학, 2008. 2. Amy Piepsz, Paula Colarinha, lsky Gordon, et all. Guidelines on 99mTc-DMSA scintigraphy in children. Eur J Nucl Med. 2001 Mar;28(3):BP37-41.