• Korean Journal of Radiology
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• v.24 no.11
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• pp.1142-1150
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• 2023

Objective: To evaluate ^99mtechnetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid (^99mTc-3PRGD₂) single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging for diagnosing lymph node metastasis of primary malignant lung neoplasms. Materials and Methods: We prospectively enrolled 26 patients with primary malignant lung tumors who underwent ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT imaging. Both imaging methods were analyzed in qualitative (visual dichotomous and 5-point grades for lymph nodes and lung tumors, respectively) and semiquantitative (maximum tissue-to-background radioactive count) manners for the lymph nodes and lung tumors. The performance of the differentiation of lymph nodes with and without metastasis was determined at the per-lymph node station and per-patient levels using histopathological results as the reference standard. Results: Total 42 stations had metastatic lymph nodes and 136 stations had benign lymph nodes. The differences between metastatic and benign lymph nodes in the visual qualitative and semiquantitative analyses of ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-FDG PET/CT were statistically significant (all P < 0.001). The area under the receiver operating characteristic curve (AUC) in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT was 0.908 (95% confidence interval [CI], 0.851-0.966), and the sensitivity, specificity, positive predictive value, and negative predictive value were 0.86 (36/42), 0.88 (120/136), 0.69 (36/52), and 0.95 (120/126), respectively. Among the 26 patients (including two patients each with two lung tumors), 15 had pathologically confirmed lymph node metastasis. The difference between primary lung lesions in patients with and without lymph node metastasis was statistically significant only in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT (P = 0.007), with an AUC of 0.807 (95% CI, 0.641-0.974). Conclusion: ^99mTc-3PRGD₂ SPECT/CT imaging may notably perform in the direct diagnosis of lymph node metastasis of primary malignant lung tumors and indirectly predict the presence of lymph node metastasis through uptake in the primary lesions.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.285-293
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• 2000

Purpose: A prospective comparison was made between imaging with Tc-99m pertechnetate (Tc-99m) and Ioine-131 (I-131) for the detection of residual and metastatic tissue after total thyroidectomy in patients with well-differentiated thyroid carcinoma. Materials and Methods: Initially our patients had imaging with Tc-99m, followed by I-131 within 3 days. The study included 21 patients who had ablation with high dose of I-131 ranging from 100 mCi to 150 mCi. Planar and pinhole images were acquired for both Tc-99m and I-131. Diagnostic images of Tc-99m and I-131 were compared with post-therapy images. Degree of uptake on Tc-99m and I-131 images was scored by four point scale and compared. Results: The results of the Tc-99m study were: 16 of 19 studies (84%) were positive on simple planar images, but 19 of 20 studies (95%) were positive on pinhole images. Conventional I-131 diagnostic imaging on the other hand showed that all studies (100%) were positive on both planar and pinhole images. There was a significant difference in degree of uptake between Tc-99m and I-131 planar images (p<0.05). Only one case of Tc-99m scintigraphy was negative on both planar and pinhole studies (false negative). There was no distant metastasis on the therapeutic I-131 images. Conclusion: Tc-99m scan using pinhole in certain clinical situations is an alternative to the I-131 scan in detecting thyroid or lymph node metastasis prior to the first ablative treatment after thyroidectomy for well-differentiated thyroid carcinoma.

• Childhood Kidney Diseases
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• v.23 no.2
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• pp.128-133
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• 2019

Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP) is a systemic vasculitis characterized by purpura, arthritis, abdominal pain, and nephritis. Gastrointestinal involvement can manifest as pain, intussusception, intestinal bleeding, and intestinal perforation. We report a case of fulminant HSP at an age of eight in 1994, with multiple complications of intra-thoracic bleeding, massive intestinal perforation, nephritis, and various skin rashes. The brisk bleeding findings of intestinal on Technetium-99m-labeled red blood cell scan ($^{99m}Tc$ RBC scan) were well matched to those of the emergency laparotomy and the resected intestine. The patient's abdominal conditions improved gradually but nodular skin eruptions developed newly apart from improving preexisting lower limb rashes and the urine findings continued abnormal, so skin and kidney biopsy were done for the diagnosis. After cyclosporine therapy, skin eruptions and urine findings returned to normal gradually. On a follow-up after 25 years in 2019, the patient is 33-year-old, healthy without any abnormality on blood chemistries and urine examination.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.248-253
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• 2023

Directly, it is not possible to measure the absorbed dose of radiopharmaceuticals in the organs of the human body. Therefore, simulation methods are utilized to estimate the dose in distinct organs. In this study, individual organs were separately considered as the source organ or target organ to calculate the mean absorption dose, which SAF and S factors were then calculated according to the target uptake via MIRD method. Here, ^99mTc activity distribution within the target was analyzed using the definition and simulation of ideal organs by summing the fraction of cumulative activities of the heart as source organ. Thus, GATE code was utilized to simulate the Zubal humanoid phantom. To validate the outcomes in comparison to the similar results reported, the accumulation of activity in the main organs of the body was calculated at the moment of injection and cardiac rest condition after 60 min of injection. The results showed the highest dose absorbed into pancreas was about 21%, then gallbladder 18%, kidney 16%, spleen 15%, heart 8%, liver 8%, thyroid 7%, lungs 5% and brain 2%, respectively, after 1 h of injection. This distinct simulation model may also be used for different periods after injection and modifying the prescribed dose.

• The Korean Journal of Nuclear Medicine
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• v.39 no.2
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• pp.94-99
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• 2005

Electrocardiogram-gated single photon omission 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-99m-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.

• The Korean Journal of Nuclear Medicine
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• v.23 no.2
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• pp.219-223
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• 1989

Inflammation scan using radiolabelled leukocytes has high sensitivity and specificity. Several methods for labelling leukocytes have been evaluated using P-32 diisopropyl fluorophosphate (DFP-32), H-3 thymidine, Cr-51 chromate, Ga-67 citrate and Tc-99m-sulfur colloid. In-111-oxine has proved so far to be the most reliable agent for labelling leukocytes. In-111-oxine is, however, expensive, not easily available when needed, and its radiation dose to leukocytes is relatively high. Moreover, resolution of the resultant image is relatively poor. Tc-99m is still the agent of choice because of, as compared with the indium, its favorable physical characteristics, lower cost and availability. Now the technique for labelling the leukocytes with technetium is successfully obtained using the lipophilic HAPAO with higher efficiency for granulocytes than for other cells. With this technique it is possible to label leukocytes in plasma to improve the viability of the leukocytes. Inflammation scan using Tc-99m-HMPAO has been evaluated in several laboratories, and difference in methods for separation and labelling accounts for difference in efficiency, viability and biodistribution of the labelled leukocytes. We performed inflammation scan using leukocytes labelled with Tc-99m-HMPAO in three dogs 24 hours after inoculation of live E. Coli and A. Aureus in their right abdominal wall. We separated mixed leukocytes by simple sedimentation using 6% hetastarch (HES) and labelled the leukocytes with Tc-99m-HMPAO in 20% cell free plama diluted with phosphate buffer solution(Fig. 1). Uptake was high in the liver and spleen but is was minimal in the lungs on whole body scan. Kidneys and intestine showed minimal activity although it was high in the urinary bladder(Fig. 2). Uptake of labelled leukocytes in the inflammation site was do(mite on 2 hour-postinjection scan and abscess was clearly delineated on 24 hour-delayed scan with high target-to-nontarget ratio(Fig. 3, 4). Inflammation scan using mixed leukocytes labelled with Tc-99m-HMPAO is very sensitive and specific in early detection of inflammation.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.3
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• pp.177-185
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• 2006

Purpose: Purpose of this study is to synthesize $^{99m}Tc$-labeled transferrin for injection imaging and to compare it with $^{67}Ga$-titrate for the detection of infectious foci. Materials and methods: Succinimidyl 6-hydrazino-nicotinate hydrochloride-chitosan-transferrin (Transferrin) was synthesized and radiolabeled with $^{99m}Tc$. Labeling efficiencies of $^{99m}Tc$-Transferrin were determined at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 8 hr. Biodistribution and imaging studies with $^{99m}Tc$-Transferrin and $^{67}Ga$-citrate were performed in a rat abscess model induced with approximately $2{\times}10^8$ colony forming unit of Staphylococcus aureus ATCC 25923. Results: Successful synthesis of Transferrin was confirmed by mass spectrometry. Labeling efficiency of $^{99m}Tc$-Transferrin was $96.2{\pm}0.7%,\;96.4{\pm}0.5%,\;96.6{\pm}1.0%,\;96.9{\pm}0.5%,\;97.0{\pm}0.7%\;and\;95.5{\pm}0.7%$ at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 8 hr, respectively. The injected dose per tissue gram of $^{99m}Tc$-Transferrin was $0.18{\pm}0.01\;and\;0.18{\pm}0.01$ in the lesion and $0.05{\pm}0.01\;and\;0.04{\pm}0.01$ in the normal muscle, and lesion-to-normal muscle uptake ratio was $3.7{\pm}0.6\;and\;4.7{\pm}0.4$ at 30 min and 3 hr, respectively. On image, lesion-to-background ratio of $^{99m}Tc$-Transferrin was $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45\;and\;5.59{\pm}0.40$ at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 10 hr and those of $^{67}Ga$-citrate was $3.06{\pm}0.84,\;4.12{\pm}0.54\;and\;4.55{\pm}0.74 $ at 2 hr, 24 hr and 48 hr, respectively. Conclusion: Transferrin is successfully labeled with $^{99m}Tc$, and its labeling efficiency was higher than 95% and stable for 8 hours. $^{99m}Tc$-Transferrin scintigraphy showed higher image quality in shorter time compared to $^{67}Ga$-citrate image. $^{99m}Tc$-transferrin is supposed to be useful in the detection of the infectious foci.

• The Korean Journal of Nuclear Medicine
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• v.34 no.5
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• pp.381-392
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• 2000

Purpose: We compared the reproducibility of $^{201}Tl\;and\;^{99m}Tc$-sestamibi (MIBI) gated SPECT measurement of myocardial function using the Germano algorithm Materials and Methods: Gated SPECT acquisition was repeated in the same position in 30 patients who received $^{201}Tl$ and in 26 who received $^{99m}Tc$-MIBI. The quantification of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) on $^{201}Tl\;and\;^{99m}Tc$-MIBI gated SPECT was processed independently using Cedars quantitative gated SPECT software. The reproducibility of the assessment of myocardial function on $^{201}Tl$ gated SPECT was compared with that of $^{99m}Tc$-MIBI gated SPECT Results: Correlation between the two measurements for volumes and EF was excellent by the repeated gated SPECT studies of $^{201}Tl$ (r=0.928 to 0.986; p<0.05) and $^{99m}Tc$-MIBI (r=0.979 to 0.997; p<0.05). However, Bland Altman analysis revealed the 95% limits of agreement (2 SD) for volumes and EF were tighter by repeated $^{99m}Tc$-MIBI gated SPECT (EDV: 14.1 ml, ESV: 9.4 ml and EF: 5.5%) than by repeated $^{201}Tl$ gated SPECT (EDV: 24.1 ml, ESV: 18.6 ml and EF: 10.3%). The root mean square (RMS) values of the coefficient of variation (CV) for volumes und EFs were smaller by repeated $^{99m}Tc$-MIBI gated SPECT (EDV: 2.1 ml, ESV 2.7 ml and EF: 2.3%) than by repeated $^{201}Tl$ gated SPECT (EDV: 3.2 ml, ESV: 3.5 ml and EF: 5.2%). Conclusion: $^{99m}Tc$-MIBI provides more reproducible volumes and EF than $^{201}Tl$ on repeated acquisition gated SPECT. $^{99m}Tc$-MIBI gated SPECT is the preferable method for the clinical monitoring of myocardial function.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.77-81
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• 1985

There are several methods for measurement of cerebral blood flow. A method using Tc-99m DTPA which was injected via antecubital vein and monitored extracranially with gamma camera is described here. In this method, the brain scan and CBF mesurement were performed with scan and CBF were usually studied separately. The results were as follow: 1) Total candidates were 53, male 34 and female 19, who have no evidence of neurologic, cardiac or kidney problems. 2) By this method, the normal CBF of Korean was $54.12{\pm}6.49ml/min/100g$ of brain tissue. 3) The CBF of male was $54.06{\pm}5.9ml/min/100g$ of brain tissue, female was $54.89{\pm}6.51ml/min/100g$, so there was no definite sex difference. 4) The CBF under 10 years of age was $54.12{\pm}2.5ml/min/100g$, $11\sim20years$ of age was $52.33{\pm}6.1ml/min/100g$, $21\sim60years$ of age was $52.86{\pm}5.06ml/min/100g$, and over 61years of age was $55.43{\pm}4.84ml/min/100g$, so there was no significant difference of CBF by age.

• Korean Journal of Biological Psychiatry
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• v.9 no.2
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• pp.152-158
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• 2002

Background & Purpose:Neuropsychological disorders after traumatic brain injury(TBI) are poorly correlated with structural lesions detected by structural neuroimaging techniques such as computed tomography(CT) scan or magnetic resonance imaging(MRI). It is well known that patients with TBI have cognitive and behavioral disorders even in the absence of structural lesions of the brain. This study investigated whether there are abnormalities of regional cerebral blood flow(rCBF) in TBI patients without structural abnormality on MRI, using technetium 99m ethyl cysteinate dimer(Tc-99m-ECD) single photon emission computed tomography(SPECT) scans. Materials and Methods:Twenty-eight TBI patients without structural abnormality on MRI(mild, n=13/moderate, n=9/severe, n=6) and fifteen normal controls were scanned by SPECT. A voxel-based analysis using statistical parametric mapping(SPM) was performed to compare the patients with the normal controls. Results:rCBF was reduced in the right uncus and the right lateral orbitofrontal gyrus in the TBI patients. However, no increase of rCBF was noted in the patients in comparison to the normal controls. Conclusions:These results suggest that the TBI patients, even in the absence of structural lesion of the brain, may have dysfunction of the brain, particularly of the orbitofrontal and anterior pole of the temporal cortex. They also suggest that SPECT can be a useful method to identify brain dysfunctions in combination with structural brain imaging and neuropsychological tests.