Fatores de correção volumétrica na medição de atividade de 99mTc e 123I em calibradores de radionuclídeos / Volume corrections factors in the measurement of 99mTc and 123I activities in radionuclide calibrators

OBJETIVO: Determinar os fatores de correção para a variação volumétrica dos radiofármacos contidos em recipientes de diferentes geometrias. Comparar a influência desses fatores na determinação da atividade de 99mTc e 123I utilizando dois tipos de calibradores: um com câmara de ionização e outro com detector Geiger-Müller (G-M). Avaliar o desempenho de calibradores de alguns serviços de medicina nuclear em medição de atividade de 99mTc e 123I. MATERIAIS E MÉTODOS: Foram utilizados oito calibradores, frascos de vidro 10R, seringas de plástico de 3 e 5 mL e soluções de 99mTc e 123I. Os fatores de correção foram determinados a partir das medições práticas da variação da leitura do calibrador com a variação do volume da solução no recipiente. O desempenho foi avaliado em relação ao critério de aceitação de ±10% de exatidão exigida pela norma brasileira. RESULTADOS: A variação da resposta do calibrador com a variação do volume do frasco foi bem maior no calibrador que utiliza G-M. Ela também foi maior para 123I do que para 99mTc. CONCLUSÃO: Os resultados confirmam que a resposta dos calibradores depende do volume contido nos recipientes. Essa dependência é mais crítica para os calibradores equipados com detector G-M e para 123I quando comparado com 99mTc.

OBJECTIVE: To determine correction factors for the variation in volume of radiopharmaceuticals in containers of different geometries, comparing the influence of such factors on the determination of 99mTc and 123I activity with two types of calibrators - one with ionization chamber and another with Geiger-Müller (G-M) detector -; and to evaluate calibrators performance in the measurement of 99mTc and 123I activities. MATERIALS AND METHODS: Eight calibrators, 10R glass vials, 3 and 5 mL plastic syringes and 99mTc and 123I solutions were utilized. The correction factors were determined with basis on practical measurements of the variation in the calibrators' response according to the volume of radionuclide solution in the glass vials. The performance was evaluated according to the acceptance criterion of ±10% accuracy required by the Brazilian standard. RESULTS: The variation of the calibrators' response according to the variation in radionuclide volume was reasonably greater in the calibrator with G-M detector. It was also greater for 123I than for 99mTc. CONCLUSION: The results confirm that the calibrators' response depends on the radionuclide volume contained in the vials. Such dependence is more critical for the calibrators equipped with G-M detector and for 123I as compared with 99mTc.

Comparison of Radioactivity Measurement with Radionuclide Calibrators in Nuclear Medicine Centers / 의학물리

To acquire good image quality and to minimize unnecessary radiation dose to patients, it is important to ensure that the radiopharmaceutical administered is accurately measured. Quality control of radionuclide calibrators should be performed to achieve these goals. The purpose of this study is to support the quality control of radionuclide calibrators in nuclear medicine centers and to investigate the level of measurement accuracy of the radionuclide calibrators. 58 radionuclide calibrators from 45 nuclear medicine centers, 74 radionuclide calibrators from 58 nuclear medicine centers, and 60 radionuclide calibrators from 45 nuclear medicine centers were tested with I-131, Tc-99m and I-123, respectively. The results showed that 81% of calibrators for I-131, 61% of calibrators for Tc-99m and 67% of calibrators for I-123 were within +/-5%. 17% of calibrators for I-131, 20% of calibrators for Tc-99m and 15% of calibrators for I-123 had a deviation in the range 5%10%. Follow-up measurements were performed on the calibrators whose error exceeded the +/-10% limit. As a result, some of the calibrator showed an improvement and their deviation decreased below the +/-10% limit. The results have shown that such comparisons are necessary to improve the accuracy of the measurement and to identify malfunctioning radionuclide calibrators.

Differentiation of Parkinson's Disease and Essential Tremor on I-123 IPT(I-123-N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta(4-cholorophenyl) tropane) Brain SPECT / 핵의학분자영상

PURPOSE: The study was to assess I-123-N-(3-iodopropen-2-yl)-2[beta]-carbomethoxy-3[beta]-(4-cholorophenyl) tropane (IPT) SPECT in differential diagnosis among early stage of Parkinson's disease(PD) and essential tremor(ET) and normal control(NL) groups quantitatively. MATERIALS AND METHODS: I-123 IPT brain SPECT of 50 NL, 20 early PD, 30 advanced PD, and 20 ET were performed at 20 minutes and 2 hours. Specific/nonspecific binding of striatum was calculated by using right and left striatal specific to occipital non-specific uptake ratio (striatum-OCC/OCC). RESULTS: Mean value of specific/nonspecific binding ratio was significantly different between advanced PD group and NL group. However, significant overlap of striatal specific/nonspecific binding ratio was observed between PD group and ET group. Bilateral striatal specific/nonspecific binding ratios were decreased in advanced PD. Lateralized differences in the striatal uptake of I-123 IPT correlated with asymmetry in clinical findings in PD group. CONCLUSION: I-123 IPT SPECT may be a useful method for the diagnosis of PD and objective evaluation of progress of clinical stages. Care should be made in the differential diagnosis of early stage of PD and other motor disturbances mimicking PD such as ET in view of significant overlap in striatal I-123 specific/nonspecific binding ratio.

Optimal Imaging Time for Diagnostic I-123 Whole Body Scan in the Follow-up of Patients with Differentiated Thyroid Cancer: Comparison between 6- and 24-Hour Images of the Same Subjects / 핵의학분자영상

PURPOSE: To determine optimal imaging time for diagnostic I-123 whole body scan in the follow-up of patients with differentiated thyroid cancer (DTC), we compared the image quality of 6- and 24-hour images of the same subjects. MATERIALS AND METHODS: Four hundred ninety-eight patients (M:F=55:443, Age 47.6+/-12.9 years) with DTC who had undergone total thyroidectomy and I-131 ablation therapy underwent diagnostic whole body scanning 6 hour and 24 hour after oral ingestion of 185 MBq (5 mCi) of I-123. Serum thyroglobulin measurement and ultrasonography of the neck were performed at the time of imaging. In 40 patients underwent additional I-131 therapy, post-therapy I-131 images were obtained and compared with diagnostic I-123 images. RESULTS: In 440 patients (88.4%), 6- and 24-hour diagnostic I-123 images were concordant, and 58 patients (11.6%) showed discordant findings. Among 58 discordant patients, 31 patients showed abnormal tracer uptake on only 6-hour image, which turned out false-positive findings in all cases. In 12 patients with positive findings on only 24-hour image, remnant thyroid tissue (4 patients) and cervical lymph node metastasis (3 patients) were presented. Among 40 patients underwent additional I-131 therapy, 6-hour and 24-hour images were discordant in 13 patients. All 5 patients with abnormal uptake on only 6-hour image revealed false-positive results, whereas most of 24-hour images were concordant with post-therapy I-131 images. CONCLUSION: I-123 imaging at 24-hour could reduce false-positive findings and improve diagnostic accuracy, compared with 6-hour image in the follow-up of patient with DTC.

Determination of Therapeutic Dose of I-131 for First High Dose Radioiodine Therapy in Patients with Differentiated Thyroid Cancer: Comparison of Usefulness between Pathological Staging, Serum Thyroglobulin Level and Finding of I-123 Whole Body Scan / 핵의학분자영상

PURPOSE: Recently, a number of patients needed total thyroidectomy and high dose radioiodine therapy (HD-RAI) get increased more. The aim of this study is to evaluate whether pathological staging (PS) and serum thyroglobulin (sTG) level could replace the diagnostic I-123 scan for the determination of therapeutic dose of HD-RAI in patients with differentiated thyroid cancer. Materials and METHODS: Fifty eight patients (M:F=13;45, age 44.5+/-11.5 yrs) who underwent total thyroidectomy and central or regional lymph node dissection due to differentiated thyroid cancer were enrolled. Diagnostic scan of I-123 and sTG assay were also performed on off state of thyroid hormone. The therapeutic doses of I-131 (TD) were determined by the extent of uptakes on diagnostic I-123 scan as a gold standard. PS was graded by the criteria recommended in 6th edition of AJCC cancer staging manual except consideration of age. For comparison of the determination of therapeutic doses, PS and sTG were compared with the results of I-123 scan. RESULTS: All patients were underwent HD-RAI. Among them, five patients (8.6%) were treated with 100 mCi of I-131, fourty three (74.1%) with 150 mCi, six (10.3%) with 180 mCi, three (5.2%) with 200 mCi, and one (1.7%) with 250 mCi, respectively. On the assessment of PS, average TDs were 154+/-25 mCi in stage I (n=9), 175+/-50 mCi in stage II (n=4), 149+/-21 mCi in stage III (n=38), and 161+/-20 mCi in stage IV (n=7). The statistical significance was not shown between PS and TD (p=0.169). Among fifty two patients who had available sTG, 25 patients (48.1%) having below 2 ng/mL of sTG were treated with 149+/-26 mCi of I-131, 9 patients (17.3%) having 2< or =sTG <5 ng/mL with 156+/-17 mCi, 5 patients (9.6%) having 5< or =sTG<10 ng/mL with 156+/-13 mCi, 7 patients (13.5%) having 10< or =sTG<50 ng/mL with 147+/-24 mCi, and 6 patients (11.5%) having above 50 ng/mL with 175+/-42 mCi. The statistical significance between sTG level and TD (p=0.252) was not shown. CONCLUSION: In conclusion, PS and sTG could not replace the determination of TD using I-123 scan for first HD-RAI in patients with differentiated thyroid cancer.

Clinical Application of I-123 MIBG Cardiac Imaging / 대한핵의학회잡지

Cardiac neurotransmission imaging allows in vivo assessment of presynaptic reuptake, neurotransmitter storage and postsynaptic receptors. Among the various neurotransmitter, I-123 MIBG is most available and relatively well- established. Metaiodobenzylguanidine (MIBG) is an analogue of the false neurotransmitter guanethidine. It is taken up to adrenergic neurons by uptake-1 mechanism as same as norepinephrine. As tagged with I-123, it can be used to image sympathetic function in various organs including heart with planar or SPECT techniques. I-123 MIBG imaging has a unique advantage to evaluate myocardial neuronal activity in which the heart has no significant structural abnormality or even no functional derangement measured with other conventional examination. In patients with cardiomyopathy and heart failure, this imaging has most sensitive technique to predict prognosis and treatment response of betablocker or ACE inhibitor. In diabetic patients, it allow very early detection of autonomic neuropathy. In patients with dangerous arrhythmia such as ventricular tachycardia or fibrillation, MIBG imaging may be only an abnormal result among various exams. In patients with ischemic heart disease, sympathetic derangement may be used as the method of risk stratification. In heart transplanted patients, sympathetic reinnervation is well evaluated. Adriamycin-induced cardiotoxicity is detected earlier than ventricular dysfunction with sympathetic dysfunction. Neurodegenerative disorder such as Parkinson's disease or dementia with Lewy bodies has also cardiac sympathetic dysfunction. Noninvasive assessment of cardiac sympathetic nerve activity with I-123 MIBG imaging may be improve understanding of the pathophysiology of cardiac disease and make a contribution to predict survival and therapy efficacy.

Dopamine Transporter Density of the Basal Ganglia Assessed with I-123 IPT SPECT in Patients with Obsessive-Compulsive Disorder / 신경정신의학

OBJECTIVES: It has been suggested that dopamine as well as serotonin were related to the pathophysiology of obsessive-compulsive disorder (OCD). Thus, many studies were performed to nivestigate brain regions and their association with dopamine in OCD patients. Recently, we have been able to monitor the density of the dopamine transporter (DAT) in the basal ganglia using I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane (I-123 IPT) SPECT, to evaluate the activity of the presynaptic dopamine function. In present study, we investigated the DAT density of the basal ganglia using I-123 IPT SPECT in patients with OCD. METHODS: Fifteen patients with OCD and nineteen normal control group were included in this study. We performed brain SPECT 2 hours after the intravenous administration of I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane (I-123 IPT) and carried out both quantitative and qualitative analyses using the SPECT, which were reconstructed for the assessment of the specific/nonspecific DAT binding ratio in basal ganglia. We then investigated the correlation between the severity of OCD symptoms assessed with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the specific/nonspecific DAT binding ratio of basal ganglia. RESULTS: Patients with OCD showed a significantly increased specific/nonspecific DAT binding ratio in right basal ganglia compared with normal controls and did not show a significantly increased specific/nonspecific DAT binding ratio, and an increased tendency in the specific/nonspecific DAT binding ratio in left basal ganglia (Rt:Z=2.584, P=0.009, Lt:=1.873, P=0.060). We found no significant correlation between the total scores of the Y-BOCS and the specific/nonspecific DAT binding ratio of basal ganglia. CONCLUSIONS: The data of this study suggest that dopamine in basal ganglia plays an important role in fronto-subcortical circuit, which are already known as a site of the pathophysiological mechanism of OCD.

Dopamine Transporter Density of the Basal Ganglia in Children with Attention Deficit Hyperactivity Disorder Assessed with I-123 IPT PECT / 대한핵의학회잡지

PURPOSE: Attention deficit hyperactivity disorder (ADHD) has been known as psychiatric disorder in childhood associated with dopamine dysregulation. In present study, we investigated changes in dopamine transporter (DAT) density of the basal ganglias using I-123 N- (3-iodopropen-2-yl) -2-carbomethoxy-3beta- (4-chlorophenyl) tropane [I-123 IPT] SPECT in children with ADHD before and after methylphenidate treatment. MATERIALS AND METHOD: Nine drug-naive children with ADHD and seven normal children were included in the study. We performed brain SPECT two hours after the intravenous administration of I-123 IPT and made both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of specific/nonspecific DAT binding ratios in the basal ganglia. All children with ADHD reperformed [123I]IPT SPECT after treatment with methylphenidate (0.7mg/kg/d) during about 8 weeks. SPECT data reconstructed for the assessment of specific/nonspecific DAT binding ratio of the basal ganglia were compared between before and after treatment methylphenidate. We investigated correlation between the change of ADHD symptom severity assessed with ADHD rating scale-IV and specific/nonspecific DAT binding ratio of basal ganglia. RESULTS: Children with ADHD had a significantly greater specific/nonspecific DAT binding ratio of the basal ganglia comparing to normal children (Right: z = 2.057, p = 0.041; Left: z = 2.096, p = 0.032). Under treatment with methylphenidate in all children with ADHD, specific/nonspecific DAT binding ratio of both basal ganglia decreased significantly greater than before treatment with methylphenidate (Right: t = 3.239, p = 0.018; Left: t = 3.133, p = 0.020). However, no significant correlation between the change of ADHD symptom severity scores and specific/nonspecific DAT binding ratio of the basal ganglia were found. CONCLUSIONS: These findings support the complex dysregulation of the dopaminergic neurotransmitter system in children with ADHD.

Levosulpiride-induced Parkinsonim

The present report discusses four cases of chronic renal failure, which developed symptoms of parkinsonism in response to levosulpiride. The temporal relationship between levosulpiride discontinuation and the disappearance of parkinsonism suggests a causal link. In addition, decreased striatal dopamine transporter bindings assessed by [I-123] IPT SPECT were observed in two patients suggesting that a dopamine blocking agent causes the dysfunction of nigrostriatal dopaminergic neurons and that such injury may be involved in the pathogenesis of drug-induced parkinsonism.

Dopamine Transporter Density of the Basal Ganglia Assessed with 123IIPT SPECT in Drug-Naive Children with Tourette's Disorder / 신경정신의학

OBJECTIVES: Previous studies in patients with Tourette's disorder suggested presynaptic dopaminergic dysfunction, demonstrating increased dopamine densities. In present study, we investigated dopamine transporter densities using I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl)tropane(I-123-IPT)-SPECT in drug-naive children with Tourette's disorder and postulated that dopamine transporter density reflected dopamine concentrations. METHODS: Eight drug-naive children with Tourette's disorder and six normal children were included in the with the brain SPECT 2 hours after an intravenous administration of I-123-IPT. Obtained SPECT data were reconstructed for the assessment of specific/nonspecific dopamine transporter binding ratio of basal ganglia and were evaluated both quantitatively and qualitatively. We investigated correlation between total tic severity of children with Tourette's disorder assessed with YGTSS and specific/nonspecific binding ratio of basal ganglia. RESULTS: Drug-naive children with Tourette's disorder had a significantly greater increase of speciffic/nonspecific dopamine transporter binding ratio of left basal ganglia than normal children. However, no significant differences in specific/nonspecific dopamine transporter binding ratio of right basal ganglia were found between children with Tourette's disorder and normal children. Also, we found no significant correlation between total tic severity of children with Tourette's disorder and specific/ nonspecific binding ratio of basal ganglia. CONCLUSION: These findings support the hypothesis of dopamine dysregulation in presynaptic dopamine function of the basal ganglia in the pathophysiology of Tourette's disorder.

Dopamine Transporter Density of the Basal Ganglia in Children with Attention Deficit Hyperactivity Disorder Assessed with I-123 IPT SPECT / 대한정신약물학회지

OBJECTIVE: ADHD has been known as a psychiatric disorder in childhood associated with dopamine dysregulation. In the present study, we investigated dopamine transporter (DAT) density using I-123N-(3-iodopropen-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane (I-123-IPT)-SPECT in children with ADHD on the hypothesis that alterations of DAT density in the basal ganglia were suggestive of dopaminergic dysfunction in children with ADHD. METHODS: Nine drug-naive children with ADHD and six normal children were included in the study. We performed brain SPECT two hours after the intravenous administration of I-123-IPT and made both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of specific/nonspecific DAT binding ratios in the basal ganglia. We then investigated the correlation between ADHD Rating Scale (ARS) scores of children with ADHD and specific/nonspecific DAT binding ratios in the basal ganglia. RESULTS: Children with ADHD had significantly greater specific/nonspecific DAT binding ratio of the basal ganglia comparing to normal children. However, no significant correlation were found between ARS scores of children with ADHD and specific/nonspecific DAT binding ratio of basal ganglia in children with ADHD. CONCLUSION: These findings support the complex dysregulation of the dopaminergic neurotransmitter system in children with ADHD.

Striatal dopamine transporter changes in patients with essential tremor and idiopathic Parkinson's disease

BACKGROUNDS: There have been controversies about the association between essential tremor (ET) and Parkinson's disease. To examine the nigrostriatal dopaminergic neurons in patients with ET, we measured the striatal dopamine transporter levels with [123I] N-(3-iodopropene-2-yl)-2?-carbomethoxy-3?-(4-chlorophenyl) tropane(IPT) single photon emission computed tomography (SPECT). METHODS: This study included nine patients with postural tremor, six patients with postural and rest tremor, 11 patients with idiopathic Parkinson's disease, and 21 age matches controls. Using triple headed gamma camera, brain SPECT scans were performed at 115 and 120 minutes after the injection of 6.23?1.37mCi(range 5-10mCi) of I123 labeled IPT. We averaged two images. Regions of interest were drawn on the middle set image at the level of basal ganglia (BG) for each subject. Amounts of striatal dopamine transporter were measured by calculating the ratio between the average counts of the basal ganglia minus occipital cortex (OCC) and the counts of the OCC((BG-OCC)/OCC). RESULTS: The mean of (BG-OCC)/OCC ratios of 9 isolated postural tremor patients (3.60?0.83) was not statistically different from that of the controls (P>0.05). However, the mean of (BG-OCC)/OCC ratios of 4 patients with postural and rest tremor (2.61?0.18) was significantly lower than that of the controls (P<0.01). Four of the six patients with postural and rest tremor had mean ratios lower than 2.0 standard deviations from the mean of the controls. CONCLUSION: In their later clinical courses, some patients with postural tremor may develop rest tremor in association with a damage in the nigrostriatal dopaminergic system.

Biodistribution and Metabolism of I-123 Labelled Fatty Acid ( I ) - 15-( p-iodophenyl ) pentadecanoic acid ( IPPA ) / 대한핵의학회잡지

I-123 labelled fatty acids are suitable for investigation of regional myocardial metabolism, so they are on the clinical trial. However, the precise properties of these materials are not characterized yet. We have synthesized phenylpentadecanoic acid and labeled this compound with I-123. The purpose of this study was to examine the stability, biodistribution, metabolism and SPECT imaging of [I-123]15-(p-iodophenyl)pentadecanoic acid(I-123-IPPA) that we made. The stability test of I-123-IPPA in serum of rat, mouse and human showed no free I-123 after 1 hour. In biodistribution study in mice for various time intervals after injection(5, 10, 15, 30, 60 minutes), uptake in myocardium was 14.5%ID/g(5 min), and 1.9%ID/heart(5 min), while uptake in muscles was 2.6%ID/g(5 min). Myocardium to blood ratio and myocardium to lung ratio increased for 5 min after injection and then decreased rapidly. Chromatographic data of rat blood and urine showed that little PPA was found in blood and urine 15-20 min after injection. The myocardial I-123-IPPA SPECT images of a dog with myocardial infarction showed defects similar to those of Tc-99m-MIBI and F-18-FDG. These data suggest that I-123-IPPA is quite stable in vitro and shows favorable biodistribution in mice. SPECT imaging with I-123-IPPA demonstrated infarct zone as photon defect in dog model of myocardial infarction. I-123-IPPA may be used for the evaluation of fatty acid metabolism in clinical trials in Korea.