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KMID : 0861420120160010027
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Korean Journal of Nuclear Medicine Technology
2012 Volume.16 No. 1 p.27 ~ p.33
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The Consideration of the Region of Interest on 99mTc-DMSA Renal Scan in Pediatric Hydronephrosis Patients
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Namkoong Hyuk
Lee Dong-Hyuk
Oh Shin-Hyun
Cho Seok-Won
Park Hoon-Hee
Kim Jung-Yul
Kim Jae-Sam
Lee Chang-Ho
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Abstract
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Purpose: Most of diagnosis in the pediatric hydronephrosis patients have been performed 99mTc-DMSA renal
scan. Then the region of interest (ROI) is set for comparative analysis of uptake ratio in left-right kidney after acquiring the image. But if the equipment set an automatic ROI, the ROI could include expanded renal pelvis due to hydronephrosis and the uptake ratio of left-right kidney will be incorrect result. Therefore this study compared both ROIs including expanded renal pelvis and excluding renal pelvis through experiment using normal kidney phantom and expanded renal pelvis phantom and suggested setting method of improved ROI. In addition, this study have been helped by readout doctor for investigate distinction radiopharmaceutical uptake between renal cortex and remained urine by expanded renal pelvis.
Materials and Methods: The both of renal phantoms were filled with water and shacked with 99mTcO4 111 MBq. In order to describe the expanded renal pelvis, the five latex balloon were all filled with 10 mL water and each of balloon was mixed with 99mTcO4 18.5, 37, 55.5, 74, 92.5 MBq. And we made phantom with fixed 99mTcO4 activity of 37 MBq and mixed water 5, 10, 15, 20, 25 mL in each balloon. The left kidney was fixed its shape and the right kidney was modified like as hydronephrosis kidney by attached the latex balloons. And the acquiring counts were 2 million. After acquisition, we compared the image of ROI with Expanded renal pelvis and the image of ROI without renal pelvis for analyzing difference in the uptake ratio of left-right kidney and for reproducibility, set the ROI 5 times in the same images. Patients were injected 99mTc-DMSA 1.5~1.9 MBq/㎏ and scanned 3 to 4 hours after injection. The each of 3 skillful radio technologists performed the comparing estimation by setting ROI. To determine statistical significance between two data, SPSS (ver. 17) Wilcoxon Signed Ranks Test was used.
Results: As a result of renal phantom’s experiment, we compared with average of counts Background (BKG) ratios in the setting of ROI including expanded renal pelvis and setting of excluding expanded renal pelvis. Therefore, they can obtain changed counts and changed ratios. Patient also can obtain same results. In addition, the radiopharmaceutical uptake in expanded renal pelvis was come out the remained urine that couldn’t descend to ureter by the help of readout doctor.
Conclusion: As above results, the case of setting ROI including expanded renal pelvis was more abnormally
increasing uptake ratio than the case of setting ROI excluding expanded renal pelvis in analysis the uptake ratio in left-right kidney of hydronephrosis. Because of the work convenience and prompted analysis, the automatic ROI is generally used. But in case of the hydronephrosis study, we should set the manual ROI without expanded renal pelvis for an accurate observation of the uptake ratio of left-right kidney since the radiopharmaceutical uptake in expanded renal pelvis is the remained urine.
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KEYWORD
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Hydronephrosis, Region of interest, 99mTc-DMSA, Uptake rate
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