• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.69-74
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• 2001

Purpose: $^{99m}Tc$-HMPAO is a radiopharmaceutical for imaging cerebral blood flow. HMPAO (RR, SS)-4.8-diaza-3,6,6,9-tetramethylundecan-2,10- dione bisoxime) has three stereoismers such as, meso-. d-, and l-HMPAO. Techentium complexes of meso-HMPAO and d,l-HMPAO are known to have different in vivo brain uptakes. In this study, enantiomers of HMPAO (d-HMPAO and l-HMPAO) were separated from d,l-HMPAO. These enantiomers were labeled with $^{99m}Tc$ and the biodistribution studies were performed in mice. Materials and Methods: An intermediate imine product was produced from 2,3-butanedione monooxime and 2,2-dimethyl-1,3-propanediamine (54% yield) and was reduced into a mixture of three isomers (35% yield). The meso-isomer was separated from d,l-mixture by repeated fractional crystallization (11 % yield). The d- and l-enantiomers were subsequently separated by co-crystallization with optical isomers of tartaric acid (25% and 5% yield. respectively). Each enantiomeric HMPAO was labeled with $^{99m}Tc$ by reacting with $SnCI_2{\cdot}2H_2O\;and\;^{99m}Tc$-pertechnetate. Biodistribution study was performed 1 hr after tail vein injection to ICR mice. Results: Radiochemical purities of each compound were over 80%. In biodistribution study. the brain uptakes of d,l- d- and l-form were 1.34, 1.12 and 1.67% ID/g, respectively. In case of l-lsomer the brain uptake was higher (1.5 fold) than d-isomer. Conclusion: We successfully purified each enantiomeric HMPAO. In biodistribution study of stereoismers of $^{99m}Tc$-HMPAO in mice, l-HMPAO may show better brain image than d,l-HMPAO which was supplied in a commercial kit.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.555-562
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• 2002

Isomers based on the RS and EZ geometrical isomerism of the neutral, deprotonated species of HMPAO and their complexes with zinc(Ⅱ) ion have been investigated by semiempirical AM1 optimization method. The Hartree-Fock energies on AM1 geometries o f HMPAO species were calculated with HF/6-31G* methods. Twenty-two isomers of the neutral and twenty isomers of the deprotonated species of HMPAO have been found. The presence of four EE-series isomers of both zinc(Ⅱ) complexes with the neutral and deprotonated HMPAO have been expected and the SREE typical isomer of both types of complexes is the most stable isomer. Energies of complexation of zinc(Ⅱ)/HMPAO isomers with AM1 geometries were calculated by HF/ 6-31G*method. Due to the complexations with zinc(Ⅱ), the structural reorganizations of some isomers of the neutral HMPAO have been occurred. The optimized geometrical parameters of the related conformations have been discussed in terms of their stabilities and existences.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.131-134
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• 2012

Purpose : The labeling efficiency of radiopharmaceuticals in nuclear medicine is important in terms of accuracy and reliability of the examination. Usually $^{99m}Tc$-HMPAO used for brain SPECT scan is chemically unstable since lots of impurities are existing. Therefore, occurrence of loss of labeling efficiency is easy to appear. In this paper, labeling and use of $^{99m}Tc$-HMPAO should be helpful through experiments on factors affecting the labeling efficiency of $^{99m}Tc$-HMPAO. Materials and Methods : Domestic HMPAO vials (Dong-A) used for brain SPECT scan were tested. Domestic Samyeong Generator 55.5 GBq (1,500 mCi), TLC measurement sets (ITLC-SG, butanone, saline, TLC chamber) and radio-TLC scanner (Advantest, Bioscan) were used. In the first experiment, after eluting generator at 1, 8, 16, 24, 28 hours apart, each eluted $^{99m}Tc$-pertechnetate were labeled with HMPAO and the labeling efficiency was measured. In the second experiment, after eluting $^{99m}Tc$-pertechnetate from a generator, $^{99m}Tc$-pertechnetate was drawn at 0, 1, 3, 6 hours. And each drawn $^{99m}Tc$-pertechnetate were labeled with HMPAO for measuring labeling efficiency. In the third experiment, labeling efficiency was measured at 0, 0.5, 3, 5, 7 hours after labeling $^{99m}Tc$-HMPAO. Results : In the first experiment, measured values were appeared 95.05, 94.64, 94.94, 95.64, 96.76% in passing order of time. In the second experiment, measured values were appeared 94.38, 94.23, 93.26, 91.03% in passing order of time. In the third experiment, measured values were appeared 95.76, 94.17, 88.19, 83.6, 76.86% in passing order of time. Conclusion : In the first experiment of this paper, labeling efficiency of $^{99m}Tc$-HMPAO labeled with $^{99m}Tc$-pertechnetate eluted after 24 hours from first elution. Additional experiments will be needed to discuss for usability. In the second experiment, the labeling efficiency was slightly decreased in chronological order, but it was measured higher than 90%. Also, additional experiments will be needed to discuss for usability. In the third experiment, the labeling efficiency was decreased considerably. Especially, within 3 hours after the labeling is recommended to use $^{99m}Tc$-HMPAO

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.293-300
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• 1994

It is well known that Tc-99m HMPAO brain SPECT can reflect the functional lesions better than X-ray computerized tomography(CT) and magnetic resonance imaging(MRI) in the cerebral disorders. In order to evaluate the clinical utilities of Tc-99m HMPAO brain SPECT in patients with post-traumatic chronic organic mental disorder(OMD), we included 28 patients diagnosed as OMD in department of psychiatry after traumatic head injury. And we compared the results of Tc-99m HMPAO SPECT with those of MRI, EEG and MINI mental status ex amination(MMSE). The results were as follows 1) All patients diagnosed as OMD showed diffuse or focal decreased cerebral perfusion on Tc-99m HMPAO SPECT. 2) Most frequent lesion on brain Tc-99m HMPAO SPECT was decreased perfusion on both frontal lobe. And most frequent lesion on brain Tc-99m HMPAO SPECT showing normal brain MRI result was also decreased both frontal perfusion. 3) Eight of 28 patients showed focal brain MRI lesions(4 small frontal hygroma, 3 small cerebral infarction and 1 cerebellar encephalomalacia) which were not detected in brain Tc-99m HMPAO SPECT. 4) The patients showing less than 20 points on MMSE disclosed abnormal results of EEG more frequently than those disclosing more than 20 points. In conclusion, we think that Tc-99m HMPAO brain SPECT is sensitive method to detect functional lesions of the brains in patients with chronic post-traumatic organic mental disorder.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.389-392
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• 2001

Tc-99m HMPAO WBC scintigraphy is a highly sensitive and specific method for detection and localization of infection and abscess formation. Nevertheless, WBC accumulation in some neoplastic lesions has been reported. We experienced a case with unusual increased uptake of Tc-99m HMPAO WBC in chondrosarcoma. Although the exact cause ms unclear, the possible mechanism is discussed.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.252-258
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• 1991

With HMPAO we have synthesized in our laboratory, we labelled $^{99m}Tc$ to canine leukocytes. Experimental abscess made by subcutaneous injection with Staphylococcus aureus was imaged with these $^{99m}Tc$ labelled leukocytes. Labelling efficiency of HMPAO with $^{99m}Tc$ was $66.2%{\pm}14.6%$ (N=9). Labelling efficiency of leukocytes with $^{99m}Tc-HMPAO$ was $54%{\pm}7.7%$ (N=7). Cell bound radioactivity in $^{99m}Tc-HMPAO$ labelled leukocytes was around 80% when these cells were incubated in plasma in vitro at $37^{\circ}C$ for 5 hours. In vivo cell bound activity was over 80% at 24 hours after injection. One day and four days after inoculation, uptake at the inflammatory focus was found with $^{99m}Tc$ labelled leukocytes. Uptake showed up in 4 hour image, and the uptake at the lesion was most prominent in 24 hour image. These findings show that in-house-synthesized HMPAO could be used for labelling leukocytes with $^{99m}Tc$, and that s$^{99m}Tc-HMPAO-labelled$ leukocytes were so stable and viable that inflammatory focus could be visualized with these $^{99m}Tc-labelled$ leukocytes.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.570-575
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• 1996

For brain perfusion SPECT imaging, $^{99m}Tc$-HMPAO and $^{99m}Tc$-ECD are commonly used. Although these two tracers usually show similar distribution, it is well known that discrepant finding might be noted between $^{99m}Tc$-HMPAO and $^{99m}Tc$-ECD imaging in some conditions. Luxury perfusion(perfusion/metabolism mismatch) is one of the examples and could be observed in subacute cerebral infarction. We report a case of subacute cerebral infarction that revealed luxury perfusion. Increased perfusion was found in $^{99m}Tc$-HMPAO SPECT and perfusion defect was found in $^{99m}Tc$-ECD SPECT. We found large area of mismatch with a consecutive acquisition-subtraction method. Crossed cerebellar diaschisis was observed in both SPECT images.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.17-26
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• 2012

Purpose: This study mainly focuses on the patients treated with chemically stable radiopharmaceutical product $^{99m}Tc$-HMPAO (d,l-hexamethylpropylene amine oxime) which yielded reduced image quality due to a decreased brain extraction rate. $^{99m}Tc$-HMPAO will be examined further to determine whether this product may be accounted as a factor for this cause. Material and Methods: From January 2010 until December 2010, out of 272 patients who were all subjected to $^{99m}Tc$-HMPAO brain blood flow SPECT scans resulting from Cerebral Infarction; 23 patients(ages $55.3{\pm}9$, 21 males, 3 females) with decreased tissue extraction rate were examined in detail. The radiopharmaceutical product $^{99m}Tc$-HMPAO was used on patients with normal brain tissue exchange rate as well as those with reduced rate in order to prove its' chemical stability. The patients' age, sex, blood pressure, existence of diabetes, drug use, current health status, known side effects from CT/MRI, examination of the patients' past SPECT before/after images were accounted to determine the factors and correlations affecting the rate of blood tissue extractions. Result: After multiple linear regression analysis, there were no unusual correlations between the 6 factors excluding sex, and before/after examination images. Male subjects showed reduced brain tissue extraction rate than the females ($p$ > 0.05) 91.3% male, 8.7% female. Wilcoxon Matched-Pairs Signed-Ranks Test was used on the before/after images which yielded a value of 0.06, which did not indicate a significant amount of difference on the 2 tests ($p$ > 0.05). As a result, the before/after images indicated similar brain tissue extraction rates, and there were variations depending on the individual patient. Conclusion: The effects of the chemically stable radiopharmaceutical product $^{99m}Tc$-HMPAO depended on the patient's personal characteristics and status, therefore was considered to be a factor in reducing brain tissue extraction rate. The related articles of $^{99m}Tc$-HMPAO cerebral blood flow SPECT speculates a cerebrovascular disease and factors resulting from portal veins, and it was not possible to pin point the exact cause of decreasing brain tissue extraction rate. However, the $^{99m}Tc$-HMPAO cerebral blood flow SPECT scan proved to be extremely useful in tracking and inspecting brain diseases, as well as offering accurate results from patients suffering from reduced brain tissue extraction rates.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.437-442
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• 2001

For ischemic cerebrovascular disease, it is well known that early luxury perfusion is related to a good clinical outcome and single photon emission computed tomography(SPECT) has the potential for providing useful information about regional cerebral blood flow. We report one case of Rt. MCA infarction mainly treated by oriental medicine and revealed luxury perfusion without thrombolysis. In acute stage, neurological deficits of the patient were very severe. 99mTc-HMPAO SPECT images obtained 10days after the attack showed large perfusion defect in the Rt. MCA territory. We followed up 99mTc-HMPAO SPECT 40days after the ictus. Despite of the poor early perfusion, we found considerably improved perfusion and neurological improvement.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.99-105
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• 2000

Computed tomography (CT) seems to be the best imaging modality to diagnose an enterovesical fistula, but is not always able to demonstrate enterovesical fistula itself. In this case report, we present Tc-99m HMPAO white blood cell (WBC) scintigraphic findings of an enterovesical fistula complicating Crohn's disease. A 22 year-old male presented with a one-month history of urinary symptoms such as dysuria, hematuria, and frequency. The patient had intermittent right lower quadrant pain, diarrhea and hematochezia. Enterovesical fistula was highly suggestive in pelvic CT which showed air density in the urinary bladder, but cystoscopy failed to find an opening of the fistula. Tc-99m HMPAO WBC scintigraphy for evaluation of inflammatory bowel disease incidentally demonstrated enterovesical fistular tract. Crohn's disease was later confirmed by histologic examination of the surgical specimen. In our patient, Tc-99m HMPAO WBC imaging was helpful in determining the location of the fistula as well as assessing the disease activity and extent of the Crohn's disease.