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Sample records for 201tl myocardial single-photon

  1. Assessment of left ventricular function using 201Tl electrocardiogram-gated myocardial single photon emission computed tomography

    International Nuclear Information System (INIS)

    Advances in computed tomography (CT) technology make it possible to obtain left ventricular wall motion using 3D reconstruction. In this study, we compared the images obtained from CT and 201Tl electrocardiogram (ECG) gated single photon emission computed tomography (SPECT). In 20 patients with ischemic heart disease, we performed 201Tl ECG gated SPECT (GE Healthcare Millennium VG) and ECG gated CT (Philips Medical Systems Brilliance iCT) to evaluate of left ventricular wall motion during the resting phase. In SPECT, left ventricular images were reconstructed using quantitative gated SPECT (QGS) software. In CT, the images were reconstructed using Virtual Place (AZE Software). The left ventricle was classified into five regions (anterior, lateral, inferior, septal, and apical). The amplitude of the wall motion was classified into five grades according to AHA classification. The values of the wall motion were separately checked by two radiographers. Assessment of left ventricular function myocardial wall movement using the three-dimensional movie display with ECG gated myocardial SPECT data was in agreement with the evaluation by cardiac CT inspection, and corresponded with wall motion in 88 of all 100 segments. SPECT analysis has the same quantity as that of obtained from CT for evaluation of left ventricular wall motion. (author)

  2. Effects of smoking on myocardial injury in patients with conservatively treated acute myocardial infarction. A study with resting 123I-15-iodophenyl 3-methyl pentadecanoic acid/201Tl myocardial single photon emission computed tomography

    International Nuclear Information System (INIS)

    Many reports have demonstrated that smokers who have suffered an acute myocardial infarction (AMI) have a better prognosis than nonsmokers. The present study investigated the effects of current smoking on myocardial injury with resting 123I-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/201Tl myocardial single photon emission computed tomography in 103 patients with conservatively treated AMI. The left ventricular myocardium was divided into 9 segments and BMIPP and 201Tl defects were scored using a 5-point grading system (0=normal and 4=no uptake). The sum of the defect scores was defined as the total defect score. There was no significant difference in either the baseline severity of the coronary artery discase or the total defect scores for BMIPP and 201Tl between the current smoker and nonsmoker groups. The difference between the total defect scores for BMIPP and 201Tl tended to be larger in the current smoker group than in the nonsmoker group (2.0±1.9 vs 1.3±1.6, p=0.056). Forty-one (53%) of 77 patients in the current smoker group exhibited a BMIPP/201Tl mismatch, whereas only 8 (31%) of 26 patients in the nonsmoker group did (p=0.047). In conclusion, current smokers had more likelihood of salvageable myocardium in areas at risk, as demonstrated by BMIPP/201Tl mismatch, in AMI than nonsmokers. (author)

  3. Single photon emission computed tomography using rotating dual gamma-camera for 201Tl myocardial imaging in patients with ischemic heart disease

    International Nuclear Information System (INIS)

    Exercise 201Tl myocardial scintigraphy was performed for comparison between single photon emission computed tomography (SEPCT) and the conventional planar method. The detection rate for ischemic heart diseases was 98% by SPECT and 86% by the planar method. The detection rate of transient ischemia in the myocardial infarction group was 70% by SPECT, 34% by the planar method and 40% by ECG (ST depression). In segmental analysis the sensitivity for the left anterior descending artery, left circumflex artery and right coronaty artery was 86%, 68% and 83%, respectively, by SPECT and 61%, 60% and 57% by the planar method. SPECT thus elevated the sensitivity in ischemic heart diseases and allowed estimation of coronary artery diseases. (Chiba, N.)

  4. Relationship between the mismatch of 123I-BMIPP and 201Tl myocardial single-photon emission computed tomography and autonomic nervous system activity in patients with acute myocardial infarction

    International Nuclear Information System (INIS)

    The purpose of this study was to elucidate the relationship between the mismatch of thallium-201 (Tl) and iodine-123-beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial single-photon emission computed tomography (SPECT) and autonomic nervous system activity in myocardial infarction (MI) patients. The subjects were 40 patients (34 males, 6 females) who underwent examinations by 123I-BMIPP and 201Tl myocardial SPECT imaging and 24-hour Holter monitoring within a 3-day period 3 weeks after the onset of their first MI. R-R intervals were analyzed every hour over a period of 24 hours by fast Fourier transformation (FFT). High frequency (HF) and low frequency (LF) were defined as markers of cardiac vagal activity in the former and the LF/HF ratio as sympathetic activity. Greater or more extensive decreases in the BMIPP image than that in the Tl image were defined as a positive mismatch. Patients were divided into positive and negative mismatch groups of 20 patients each. There were no significant differences between the 2 groups in age, sex, site of infarction, max CK (creatine kinase), max CK-MB, or left ventricular ejection fraction. The incidences of clinical signs suggesting residual myocardial ischemia were significantly greater in the positive than in the negative mismatch group (P123I-BMIPP and 201Tl myocardial SPECT 3 weeks after a first acute myocardial infarction with uncomplicated moderate or severe heart failure and decreased heart rate variability are related to residual myocardial ischemia. A combined assessment of heart rate variability in 24 hour Holter electrocardiogram (ECG) monitoring and perfusion-metabolism mismatch in 123I-BMIPP and 201Tl myocardial SPECT is useful for determining residual myocardial ischemia in the follow-up of those with acute myocardial infarction. (author)

  5. Usefulness and limitation of stress 201Tl myocardial single photon emission computed tomography (SPECT) for diagnosis of ischemic heart disease

    International Nuclear Information System (INIS)

    Stress 201-T1-myocardial single photon emission computed tomography (SPECT) proved to have significantly higher sensitivity than planar scintigraphy for the detection of ischemic heart disease (IHD), each affected artery, multi-vessel disease and three-vessel disease. It also permitted the detection of ventricular aneurysm. Diagnostic accuracy was influenced by the presence and severity of infarction, the number of affected vessels, and infarct site. Transient ischemia in the infarct site and ventricular aneurysm seemed to make it difficult to detect multi-vessel disease in cases of infarction. These resu lts indicated that SPECT is a noninvasive useful technique for detecting IHD, each affected artery, multi-vessel disease (especially, postero-inferior myocardial infarction), three-vessel disease, and ventricular aneurysm. However, SPECT seemed to have the limitation for detecting multi-vessel disease accompanied by anterior myocardial infarction and angina pectoris. (Namekawa, K.)

  6. Evaluation of Agreement between 64-slice Computed Tomography Angiography and 201-Tl Single Photon Emission Computed Tomography-myocardial Perfusion Imaging in the Diagnosis of Significant Coronary Artery Disease

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    Ma, Jee Hyun; Kang, Doo Kyoung [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, Su Jin; An, Young Sil [Dept. of Nuclear Medicine, Ajou University School of Medicine, Suwon (Korea, Republic of); Lim, Hong Seok [Dept. of Cardiology, Ajou University School of Medicine, Suwon (Korea, Republic of)

    2011-06-15

    To compare coronary computed tomography angiography (CTA) with single photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) for the detection of physiologically significant coronary artery disease (CAD). We evaluated 202 patients undergoing 64-slice coronary CTA and 201-Tl SPECT-MPI within a 3-month time interval. In addition, 68 patients underwent invasive coronary angiography (ICA). Coronary artery stenoses with luminal narrowing {>=} 50% were defined as 'significant' on CTA and ICA. All myocardial segments were classified as reversible or fixed perfusion defects and normal segments on 201-Tl SPECT-MPI, and were allocated to the corresponding coronary vessels. Agreement and diagnostic performance between each imaging modality for physiologically significant CAD was calculated using the kappa ({kappa}) statistic and receiver operating characteristic analysis, respectively. The sensitivity and specificity of CTA for the detection of physiologically significant CAD were 88% and 86% by patient-based analysis, and 84% and 91% by vessel-based analysis as compared to 201-Tl SPECT-MPI, respectively. The agreement between CTA and SPECTMPI was good ({kappa} = 0.647) and moderate ({kappa} = 0.558) by patientand vessel-based analyses, respectively. The accuracy of CTA for predicting perfusion defects on SPECT-MPI was comparable (area under the curve; 0.814 vs. 0.819, p=0.902 on patient-based analysis, and 0.808 vs. 0.749, p=0.197 on vessel-based analysis) to ICA. Coronary stenosis {>=} 50% on coronary CTA shows good agreement with perfusion defects in SPECT-MPI.

  7. Myocardial scintigraphy with 201Tl in angiosarcoma of the heart

    International Nuclear Information System (INIS)

    The appearance of angiosarcoma of the heart in the myocardial image with 201Tl is described on hand of an casuistic example. This diagnostic procedure may be important for follow-up of therapeutic effects. (orig.)

  8. 123I-labelled BMIPP fatty acid myocardial scintigraphy in patients with hypertrophic cardiomyopathy: SPECT comparison with stress 201Tl

    International Nuclear Information System (INIS)

    123I-labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) was performed in 17 patients with hypertrophic cardiomyopathy, and was compared with 201Tl exercise stress myocardial perfusion (SPECT) images. Fourteen patients showed asymmetrical hypertrophy, and three demonstrated apical hypertrophy. SPECT was performed 20 min and 3 h after injection of 111 MBq 123I-BMIPP at rest. Exercise stress 201Tl SPECT was performed at 10 min and 3 h after injection and was compared with BMIPP imaging. In 13 patients BMIPP accumulation in the hypertrophied area in the 20 min image was lower that that of 3 h 201Tl uptake. Interestingly, six patients demonstrated 201Tl redistribution in the region where the uncoupling of BMIPP uptake at 20 min and 201Tl accumulation at 3 h after exercise was observed. These findings suggest that impaired fatty acid metabolism or utilization in hypertrophic myocardium and ischaemia or impaired coronary flow reserve may be one of the causes of the abnormality of fatty acid accumulation. (Author)

  9. Effects of smoking on lung uptake of 201Tl during exercise myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Objective: To investigate the influence of smoking on lung uptake of 201Tl during myocardial perfusion imaging. Methods: Ninety-two healthy subjects, with normal 201Tl myocardial perfusion imaging findings but no evidence of left ventricular hypertrophy and pulmonary disease, were divided into three groups, smoker, nonsmoker and quitted smoker groups. Exercise/delay 201Tl myocardial perfusion imaging was performed on all subjects included. Lung/heart ratio was defined on the anterior planar image obtained during exercise tomography. Results: Both the lung/heart ratios during exercise in smoker (0.40 ± 0.07, F=10.635, P201Tl lung/heart ratios in smokers are higher than in nonsmokers and this must be kept in mind when 201Tl lung/heart ratios are used clinically, even in quitted smokers

  10. Value of dipyridamole stress 201Tl myocardial SPECT in detecting dysfunction of coronary microcirculation

    International Nuclear Information System (INIS)

    Objective: To evaluate the value of dipyridamole stress 201Tl myocardial SPECT in detecting dysfunction of coronary microcirculation. Methods: Forty-eight patients diagnosed with cardiac syndrome X underwent dipyridamole stress 201Tl myocardial SPECT. Dipyridamole (0.56 mg/kg) was intravenously injected over 4 min followed by 201Tl (111 MBq) injection at 2 min after dipyridamole administration. Image was acquired at 10 min and 240 min post-injection and co-analyzed by over two experienced doctors in nuclear medicine after three-dimensional reconstruction. The patients with 'reverse redistribution' underwent repeated dipyridamole stress 201Tl SPECT after medical therapy for 2 weeks. The clinical symptoms and results of the treadmill exercise test pre-and post-therapy were compared. Results: Forty two patients (42/48, 87.50%) showed segmental defects: 'reverse redistribution' on delayed (240 min)201Tl images. After medical treatment, 36 cases of the 42 'reverse redistribution' patients had improvement in both clinical symptoms and treadmill exercise test. Post-treatment 201Tl imaging showed improvement in 45/49 (91.84%) defect segments. Six of the 42 patients had no improvement in clinical symptoms and/or treadmill exercise test. Post-treatment 201Tl imaging showed no improvement in all the 7 defect segments on the first scan. Conclusion: Dipyridamole stress 201Tl myocardial SPECT may be valuable in evaluation of impaired coronary microcirculation associated with cardiac syndrome X. (authors)

  11. 201Tl in myocardial diagnosis: studies on the influence of dipyridamole, dobutamine ergometer exercise and background subtraction on the 201Tl myocadial scintiscam

    International Nuclear Information System (INIS)

    Changes in 201Tl myocardial scintiscans upon administration of dipyridamole or dobutamine and upon ergometer exercise relative to scintiscans at rest were investigated as well as the influence of myocardial background subtraction on scintiscan quality and information. A total of 90 201Tl examinations were carried out in 59 patients. 18 patients had no myocardial disease, 30 patients had a coronary disease, 5 patients suffered from cardiomyopathy and 6 from left ventricular hypertrophy. The findings are discussed in detail. (orig.)

  12. Assessment of myocardial viability with 201Tl myocardial SPECT 24 hours after injection

    International Nuclear Information System (INIS)

    Recently many investigators reported that conventional stress-redistribution myocardial scintigraphy with 201Tl underestimated the presence of ischemia but viable myocardium. We studied single photon emission computed tomography (SPECT) to assess myocardial viability and investigated the factors affecting the quality of 24 hour SPECT images. Study patients were comprised of 70 patients with old myocardial infarction (OMI), 72 patients with angina pectoris without OMI (AP), and 43 patients with angiographically proven normal coronary arteries. To obtain SPECT images, 10 minute and 4 hour imagings were sampled 30 seconds per projection. Twenty-four hour imaging was sampled 60 seconds per projection. Twenty-four hour images were visually interpreted as good, moderate, and poor quality. Then study patients were divided into 2 groups, group A with good 24 hour images and group B with moderate or poor 24 hour images. One hundred and fifty-eight patients (85.4%) of study patients had 24 hour SPECT images on a good quality. Only 4 patients (2.2%) had poor quality SPECT. All of these 4 patients had broad myocardial infarction. In patients with OMI 61 patients (87.1%) in AP 63 patients (87.5%) and in normal 35 patients (81.4%) had a good 24 hour SPECT. Total sampling counts and myocardial ROI counts were significantly higher in group A than in group B. Body weight was significantly higher and there were more male patients in group B than in group A. Late redistribution was seen in 20 patients (28.5%) with OMI and in 11 patients (15.3%) with AP. In most patients with OMI and AP we can get 24 hour SPECT on a good quality. In patients with moderate or poor 24 hour SPECT sampling counts were significantly reduced. So, it may be possible to get good quality 24 hour image with longer sampling time. (author)

  13. Dipyridamole 201Tl myocardial SPECT imaging in patients with dilated cardiomyopathy

    International Nuclear Information System (INIS)

    Objective: To explore the characteristics of dipyridamole 201Tl myocardial perfusion imaging (MPI) SPECT in patients with dilated cardiomyopathy. Methods: Thirty patients with dilated cardiomyopathy underwent pharmacological stress 201Tl MPI SPECT after intravenous infusion of dipyridamole (0.56 mg/kg) for 4 min. The early and delayed SPECT images were acquired respectively at 10 and 240 min after 201Tl injection. The images were analyzed and reported by two or three experienced nuclear medicine physicians. Results: All patients were found to have abnormal perfusion patterns at delay imaging, however 90.00% (27/30) were also abnormal at early images. Six patients had reverse redistribution. Conclusion: Dipyridamole 201Tl MPI SPECT imaging may be of some value for the assessment of patients with dilated cardiomyopathy. (authors)

  14. Degradation of myocardial perfusion SPECT images caused by contaminants in thallous (201Tl) chloride

    International Nuclear Information System (INIS)

    Thallous (201Tl) chloride is a single-photon emission computed tomography (SPECT) tracer mainly used for assessing perfusion and viability of myocardial tissue. 201Tl emits X-rays around 72 keV and gammas at 167 keV, and has a half-life of 73 h. Regulations allow an intrinsic contamination up to 3-5%, which is mainly caused by 200Tl (368 keV; 26 h) and by 202Tl (439 keV; 12.2 days). Contra-intuitive to the low-level percentages in which these contaminants are present, their impact may be significant because of much higher gamma camera sensitivity for these high-energy photon emissions. Therefore, we investigate the effects of the contaminants in terms of detected fractions of photons in projections and contrast degradation in reconstructed images. Acquisitions of a digital thorax phantom filled with thallous (201Tl) chloride were simulated with a validated Monte Carlo tool, thereby, modelling 1% of contamination by 200Tl and 202Tl each. In addition, measurements of a thorax phantom on a dual-headed gamma camera were performed. The product used was contaminated by 0.17% of 200Tl and 0.24% of 202Tl at activity reference time (ART). This ART is specified by the manufacturer, thereby, accounting for the difference in half-lives of 201Tl and its contaminants. These measurements were repeated at different dates associated with various contamination levels. Simulations showed that, with 1% of 200Tl and 202Tl, the total contamination in the 72 keV window can rise up to one out of three detected photons. For the 167keV window, the contamination is even more pronounced: more than four out of five detections in this photopeak window originate from contaminants. Measurements indicate that cold lesion contrast in myocardial perfusion SPECT imaging is at maximum close to ART. In addition to a higher noise level, relative contrast decreases 15% 2 days early to ART, which is explained by an increase in 200Tl contamination. After ART, contrast decreased by 16% when the 202Tl contamination increased to the maximal allowed limit. Contra-intuitive to the low-level percentages in which they are typically present, penetration and downscatter of high-energy photons from 200Tl and 202Tl significantly contribute to thallous (201Tl) chloride images, thereby, reducing contrast and adding noise. These findings may prompt for improved production methods, for updated policies with regard to timing of usage, and they also render the usefulness of adding the high photopeak window (167 keV) questionable. A window-based correction method for this contamination is advisable. (orig.)

  15. Detecting viable hibernating myocardium in chronic coronary artery disease. A comparison of resting {sup 201}Tl single photon emission computed tomography (SPECT), {sup 99m}Tc-methoxy-isobutyl isonitrile SPECT after nitrate administration, and {sup 201}Tl SPECT after {sup 201}Tl-glucose-insulin infusion

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    Toyama, Takuji; Hoshizaki, Hiroshi; Isobe, Naoki; Adachi, Hitoshi; Naito, Shigeto; Oshima, Shigeru; Taniguchi, Koichi [Gunma Prefectural Cardiovascular Center, Maebashi (Japan)

    2000-12-01

    To identify and quantify the amount of viable hibernating myocardium in patients with chronic coronary artery disease, resting {sup 201}Tl single photon emission computed tomography (SPECT) was compared with {sup 99m}Tc-methoxy-isobutyl isonitrile (MIBI) SPECT after nitrate infusion (nitrate-{sup 99m}Tc-MIBI) and {sup 201}Tl SPECT after {sup 201}Tl with glucose-insulin-potassium infusion ({sup 201}Tl-GIK) in 25 patients. Twenty-one patients also underwent completely left ventriculography beforehand and 5{+-}4 months afterwards. SPECT images were divided into 9 segments and scored visually from 0 (normal uptake) to 3 (absent). The defect score was calculated as the summation of the total scores (TDS) in each patient. The TDS of nitrate-{sup 99m}Tc-MIBI images (6.3{+-}4.3) and {sup 201}Tl-GIK images (5.8{+-}4.2) were significantly lower than the 7.4{+-}4.3 of resting {sup 201}Tl images (p<0.01). Based on the improvement of wall motion after coronary revascularization, the sensitivity of {sup 201}Tl-GIK imaging (85%) was significantly higher (p<0.05), and that of nitrate-{sup 99m}Tc-MIBI imaging (79%) also tended to be higher (p=0.08), than that of {sup 201}Tl imaging (62%) in detecting viable myocardium. The specificity of the 3 methods was almost the same. The nitrate-{sup 99m}Tc-MIBI and {sup 201}Tl-GIK methods were more useful than the resting {sup 201}Tl method for evaluating viable hibernating myocardium. Furthermore, the {sup 201}Tl-GIK method may provide a more accurate estimate of the amount of viable myocardium than the nitrate-{sup 99m}Tc-MIBI method. (author)

  16. Myocardial scintigraphy with 201Tl in coronary disease

    International Nuclear Information System (INIS)

    106 normal subjects, infarct patients or patients with signs of ischemic ECG were examined by 201Tl-scintigraphy. A dosis of 1.5 mCi immediately resulted in satisfactory scintiscanner images, as well as with the gamma camera. 81% of the patients with anterior infarction, 63% of patients with inferior infarction and 22% of patients with sub-epicardial ischemia showed characteristic scintigraphic anomalies. 201Tl was therefore demonstrated to be a valuable tracer for anterior infarction diagnosis. It was found to be less exact in inferior infarction, although still superior to the 131Cs hitherto used by the authors

  17. Evaluation of infantile ventricular tachycardia by sup 201 Tl myocardial SPECT

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    Akanabe, Hiroshi; Sakuma, Sadayuki (Nagoya Univ. (Japan). Faculty of Medicine); Ohshima, Motoo

    1992-04-01

    {sup 201}Tl myocardial SPECT findings in infantile ventricular tachycardia (VT) were examined. The subjects were 4 cases of infantile VT subjected exercise-loading {sup 201}Tl scintigraphy in 1990. These cases (3 males and 1 female) were aged 11-14 years, being persistent and non-persistent type VT (2 cases each). Echocardiography revealed no abnormal findings in these 4 cases. Exercise-loading was performed by means of sitting ergometer. ECG revealed sinus arrhythmia except for one case which throughout its course of treatment, had already been presenting ventricular extrasystole from before the excercise-loading. Myocardial SPECT revealed persistent defects (antero-septal wall defects in three cases). The above suggests that {sup 201}Tl myocardial SPECT enables us to search for etiology of VT, prognosis and the like. (author).

  18. Usefulness of {sup 201}Tl/{sup 123}I-BMIPP myocardial SPECT to evaluate myocardial viability and area at risk in acute myocardial infarction. Comparison with {sup 201}Tl/{sup 99m}Tc-PYP dual SPECT

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    Isobe, Naoki; Toyama, Takuji; Hoshizaki, Hiroshi; Oshima, Shigeru; Taniguchi, Koichi [Gunma Prefectural Cardiovascular Center, Maebashi (Japan)

    1997-04-01

    To evaluate the area at risk and the myocardial viability of acute myocardial infarction (AMI), we compared rest {sup 123}I-beta-methyl iodophenyl pentadecanoic acid ({sup 123}I-BMIPP) and {sup 201}Tl myocardial SPECT with {sup 201}Tl/{sup 99m}Tc-PYP dual SPECT (D-SPECT) in 65 patients (mean age 64{+-}11 years) with AMI. D-SPECT was performed in 3 to 5 days, {sup 123}I-BMIPP myocardial SPECT in 5 to 7 days, and left ventriculography on 1 month after onset of AMI. Furthermore, {sup 201}Tl/{sup 123}I-BMIPP myocardial SPECT and left ventriculography were performed on 4 months after onset of AMI. The area which showed the reduced {sup 123}I-BMIPP uptake was larger than that showed the accumulation of {sup 99m}Tc-PYP. The improvement of regional wall motion on 4 months after onset of AMI tended to be more closely correlated with the existence of discrepancy zone between {sup 201}Tl and {sup 123}I-BMIPP uptake than that of overlap zone between {sup 201}Tl and {sup 99m}Tc-PYP uptake in acute period. We conclude that {sup 201}Tl/{sup 123}I-BMIPP myocardial SPECT is more useful to evaluate the area at risk and myocardial viability of AMI than D-SPECT. (author)

  19. Quantitative analysis of 123I-BMIPP imaging in relation to exercise-redistribution 201Tl in patients with old myocardial infarction

    International Nuclear Information System (INIS)

    Myocardial kinetics of 123I-labeled 15-(p-iodophenyl) 3R, S-methylpentadecanoic acid (BMIPP) was evaluated with BMIPP imaging in conjunction with stress-201Tl. We studied 20 patients with old myocardial infarction. BMIPP SPECT was obtained at 20 min and 3 h after injection. On a separate day, exercise stress-201Tl SPECT was performed at 10 min and 3 h after injection. Then, left ventricular myocardium was divided into 20 segments. For quantitative analysis, in each SPECT data, the maximum value (average counts per pixel) of all 20 myocardial segments was taken as 100%; the other values were calculated as a percentage of this maximum (Relative regional uptake, RRU). On the basis of stress-201Tl pattern, the myocardial segments were classified into 4 groups; normal 201Tl uptake, reversible 201Tl defect, fixed 201Tl defect and 201Tl defect with reverse redistribution. The 20 min BMIPP showed reduced activity compared with 3 h-201Tl (p201Tl redistribution (50/111 segments, 45%), implicating impaired fatty acid utilization at resting condition. The washout rate of the segments with reversible 201Tl defect (-1.6±13.9%) was significantly lower than that of the segments with normal 201Tl uptake (9.0±9.8%) and fixed 201Tl defect (3.8±12.9). Thus, BMIPP in combination with stress 201Tl imaging provides precise information on impaired myocardial fatty acid utilization in patients with old myocardial infarction. (author)

  20. Scintigraphy of the heart with the aid of 201Tl in diagnosis of acute myocardial infarction

    International Nuclear Information System (INIS)

    In patients with acute myocardial infarction of different localization by the method of heart scitigraphy using 201Tl irradiation doses, extraction factors in myocardium, 201Tl distribution in the heart are considered. A good correlation between ECG data and scintigraphy as to myocardium localization is pointed out. Advantages (availability, acceptable radiation doses, high sensitivity for the first 12-24 hours after the appearence of first symptoms etc.) and disadvantages (impossibility of the differentiating of acute, developing or ''chronic'' infarction) of the method are shown

  1. Long term retention and excretion of 201Tl in a patient after myocardial perfusion imaging

    International Nuclear Information System (INIS)

    201Tl is widely used in nuclear medicine to carry out myocardial perfusion imaging (MPI). However, very limited data is available on long-term distribution in the body, excretion and corresponding dose. In this study we performed a 2 month follow-up of a patient who underwent MPI, by urine analysis and in vivo measurements. The biological half-life of thallium was consequently estimated to be 11.6-27 d, which is in partial agreement with previous studies. We also estimated excretion and retention of 200Tl, 201Tl and 202Tl isotopes using the biokinetic parameters from ICRP publication 53 and compared the forecast result with actual measurements. The latter demonstrated a higher urinary excretion and a higher body retention than what was expected. Our results therefore suggest that the long-term retention and consequently the effective dose coefficient for 201Tl considered in ICRP publications 53 and 80 may be slightly underestimated. (authors)

  2. Long term retention and excretion of 201Tl in a patient after myocardial perfusion imaging.

    Science.gov (United States)

    Blanchardon, E; Challeton-de Vathaire, C; Boisson, P; Célier, D; Martin, J-C; Cassot, S; Herbelet, G; Franck, D; Jourdain, J R; Biau, A

    2005-01-01

    201Tl is widely used in nuclear medicine to carry out myocardial perfusion imaging (MPI). However, very limited data is available on long-term distribution in the body, excretion and corresponding dose. In this study we performed a 2 month follow-up of a patient who underwent MPI, by urine analysis and in vivo measurements. The biological half-life of thallium was consequently estimated to be 11.6-27 d, which is in partial agreement with previous studies. We also estimated excretion and retention of 200Tl, 201Tl and 202Tl isotopes using the biokinetic parameters from ICRP publication 53 and compared the forecast result with actual measurements. The latter demonstrated a higher urinary excretion and a higher body retention than what was expected. Our results therefore suggest that the long-term retention and consequently the effective dose coefficient for 201Tl considered in ICRP publications 53 and 80 may be slightly underestimated. PMID:15671052

  3. The role of 201Tl SPECT in detecting myocardial viability in patients undergoing trans-myocardial laser revascularization

    International Nuclear Information System (INIS)

    Objective: To evaluate the value of detecting viable myocardium by 201Tl SPECT myocardial imaging in trans-myocardial laser revascularization (TMLR). Methods: 19 patients with prior myocardial infarction and unstable angina confirmed by coronary angiography underwent TMLR. Before TMLR, dipyridamol stress test (ST)-'redistribution' (RD)-nitroglycerin (NTG) infusion re-injecting (NTG+RI)201Tl SPECT myocardial imaging were performed on all 19 patients. Of 56 segments of left ventricle with myocardial ischemia or infarction found by 201Tl SPECT imaging, 45 segments (physicians' decision) underwent TMLR using a high energy (800 W) CO2 laser. TMLR was performed on the free walls of the left ventricle of the beating heart. The average numbers of trans-myocardial channels on various segments were: 8.3 +- 2.9 on anterior wall, 6.5 +- 2.5 on lateral wall, 5.4 +- 2.0 on inferior wall, 5.3 +- 4.4 on apex. 3, 6 to 12 months after TMLR, ST-RD-NTG+RI 201Tl SPECT imaging was repeated in 19 patients, and then followed up for 3 months in 17 cases, 6 months in 11 cases, 1 year in 5 cases. Results: Of 45 segments which had TMLR, 18 segments (40%) showed improved perfusion of myocardium. Of 18 segments showed marked redistribution before TMLR, 14 segments (77.8%) were improved in myocardial perfusion after TMLR. All of 8 segments showed marked redistribution in RD imaging before TMLR showed improved myocardial perfusion after TMLR. Among 27 segments without redistribution in RD-NTG+RI 201Tl myocardial imaging, only 4 segments (14.8%) showed improved perfusion after TMLR. Conclusions: Stress test-redistribution-NTG infusion + reinjection 201Tl myocardial imaging is a valuable procedure to select patients for TMLR and to evaluate results of TMLR therapy

  4. Detection of coronary artery stenosis in children with Kawasaki disease. Usefulness of pharmacologic stress 201Tl myocardial tomography

    International Nuclear Information System (INIS)

    This study determined the feasibility and accuracy of quantitative 201Tl myocardial single-photon emission computed tomography (SPECT) after dipyridamole infusion to detect coronary obstructive lesions in children with Kawasaki disease. 201Tl distribution after dipyridamole infusion was measured in 23 normal children, and with these normal values, quantitative analysis of SPECT was performed in 49 patients. Thirty-four patients had coronary stenosis 90% or greater on angiograms. Side effects resulting from systemic vasodilation were observed in about 70%. Angina pectoris and ischemic ST changes were observed only in patients with coronary stenosis. These symptoms disappeared after aminophylline infusion. Results of visual and quantitative analysis of SPECT were compared. SPECT data were shown on two-dimensional polar maps, and the extent and severity scores were calculated. The sensitivity of SPECT for detection of overall coronary stenosis was 91% (visual analysis) and 88% (quantitative analysis). The specificity of SPECT was 60% visually and 93% quantitatively. The sensitivity of quantitative analysis to detect individual coronary stenosis was similar to that of visual analysis. However, the specificity of visual analysis to detect individual coronary artery stenosis was significantly less than that of quantitative analysis. From these data, we conclude that quantitative analysis of myocardial SPECT after dipyridamole infusion is a safe and accurate diagnostic method for identifying coronary stenosis in children with Kawasaki disease

  5. ATP-loading 201Tl myocardial SPECT for the detection of ischemic heart disease

    International Nuclear Information System (INIS)

    To evaluate the usefulness for the detection of ischemic heart disease, ATP myocrdial SPECT was performed in 35 patients (mean; 59±9.4 years) with angina pectoris or old myocardial infarction. Coronary angiography (CAG) was performed in all patients. The ultra-short half-life of ATP required a continuous infusion for its use. ATP was infused intravenously at a rate of 0.16 mg/kg/min for 5 min, with 201Tl injection taking place at 3 min. Myocardial SPECT imaging was begun 5 min and 4 hr later after the end of ATP infusion. ATP caused a significant decrease in arterial blood pressure (p201Tl myocardial SPECT for the detection of coronary artery disease (CAD) was evaluated using CAG as a golden standard. The sensitivity and specificity for CAD detection were 82% and 90%, respectively. ATP myocardial SPECT is a promising new test for the detection of ischemic heart disease. (author)

  6. Effect of wall thickness of left ventricle on 201Tl myocardial SPECT images. Myocardial phantom study

    International Nuclear Information System (INIS)

    201Tl myocardial SPECT is known for better sensitivity, specificity, and accuracy than planar images in detecting coronary artery disease and diagnosing myocardial viability. SPECT images arc also superior to planar images in diagnostic sensitivity and anatomical orientation. However, as limitation of the spatial resolution of the machine, we often encounter poor SPECT plower image quality in patients with decreased wall thickness. To test the accuracy of SPECT images in patients with marked thinning of the left ventricular wall, as occurs in dilated cardiomyopathy, we performed a experimental study using myocardial phantom with 7 mm wall thickness. Tomographic image of the phantom images were rather heterogeneous, though no artificial defect was located Dilated cardiomyopathy is thought to be characterized by patchy defects in the left ventricle. Careful attention should be given to elucidating myocardial perfusion in patients with a thin left ventricle wall, as there are technical limitations in addition to clinical features. (author)

  7. Quantitative assessment of myocardial blood flow by measurement of fractional myocardial uptake of 201Tl

    International Nuclear Information System (INIS)

    Fractional Myocardial uptake of 201Tl was measured for the quantitative assessment of myocardial blood flow in coronary artery disease (CAD). 10 normals and 28 CAD, 7 of which have less than 50% stenosis (CAD I) and 21 of which have more than 50% stenosis (CAD II) in the proximal portion of coronary arteries, were studied at rest and with submaximal exercise loading by bicycle ergometer. After intravenous injection of 201Tl, its rapid transport process was recorded during the initial 5 minutes by a scintillation camera and a minicomputer. Total injected dosage (T) was obtained from the counts of the entire chest region during the initial passage of the tracer through the heart and lung. Myocardial uptake (M) was counted with the same geometry from the subsequent accumulation within the myocardial region with subtraction of the background activities in the upper mediastinal region (B). The fractional myocardial uptake of 201Tl ((M-B)/T) is assumed to be proportional to the fractional myocardial blood flow to cardiac output (MBF/CO) according to the indicator fractionation principle. The average value of MBF/CO at rest in CAD (4.11 +- 1.12%) was significantly greater than in normals (3.36 +- 0.49%), which may be caused by an increased left ventricular mass in CAD. Change rate of MBF/CO on the exercise loading was significantly less in CAD I (1.36 +- 0.14) and in CAD II (1.11 +- 0.21) than in normals (1.75 +- 0.11). MBF/CO increased proportionally to the increment of the double product of heart rate and systolic blood pressure by exercise loading in normals, whereas it didn't in CAD. The sensitivity of this method was superior to the stress electrocardiogram and the stress myocardial perfusion imaging, not only in CAD II but also in CAD I. This result indicated that this type of global assessment of the myocardial reserve capacity is valuable in addition to the simple stress myocardial perfusion imaging. (author)

  8. Is the cardiac function improvement after PTCA predictable by the quantitative indices from exercise stress 201Tl myocardial SPECT, in patients with old myocardial infarction?

    International Nuclear Information System (INIS)

    We examined whether the improvement of left ventricular function after percutaneous transluminal coronary angioplasty (PTCA) in patients with one diseased vessel can be predicted by the quantitative indices from exercise stress 201Tl single photon emission computed tomography (SPECT) and radionuclide angiography (RNA) before PTCA. Exercise stress 201Tl myocardial SPECT and RNA were performed before and after PTCA in 28 patients with old myocardial infarction (OMI). The patients were divided into two groups according to the results of coronary angiogram performed at 3 to 6 months after PTCA; patency was confirmed in 22 patients (Group P) and restenosis was observed in the remaining 6 patients (Group S). In Group P, the count ratios defined as 201Tl uptake in the PTCA region divided by the uptake in the normal region were significantly improved at 1 week and 3 to 6 months after PTCA in the initial image. 201Tl washout rates in the normal regions were significantly increased at 1 week after PTCA in Group S, and these rates in the PTCA regions were significantly increased at 1 week after PTCA in Group P. Left ventricular ejection fractions (LVEF) obtained from RNA were significantly improved 1 week and 3 to 6 months after PTCA in Group P. The changes of LVEF between pre-PTCA and 3 to 6 months after PTCA (?LVEF) were significantly correlated with the count ratios of both initial and delayed SPECT images in Group P (r=0.652; p<0.01, r=0.645; p<0.01 respectively). From the multiple regression analysis using stepwise methods, the count ratio in delayed image and the LVEF before PTCA were selected as independent predictive variables for ?LVEF (multiple correlation coefficient=0.776). Thus, the improvement of LVEF after PTCA may be predictable by the count ratio in the delayed SPECT image and LVEF before PTCA when the treated vessel is persistently patent. (author)

  9. Clinical evaluation of efonidipine hydrochloride in angina pectoris. Evaluation in exercise 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    Clinical usefulness of once-daily administration of 20 to 60 mg of efonidipine hydrochloride and coronary hemodynamics during exercise 201Tl myocardial scintigraphy were investigated in patients with angina pectoris. Out of 11 patients enrolled in this study, 9 patients were included in the evaluation of patients' impression, in improvement rating in subjective symptoms, in the analysis of the exercise test, in the improvement rating of images on 201Tl myocardial scintigraphy, and in the global improvement rating, while 10 patients were included in the overall safety rating. Four patients in improvement rating in subjective symptoms, 2 in improving rating in the exercise test, and 5 in the global improvement rating were rated 'improved' or better. In the improvement rating on the exercise 201Tl myocardial scintigraphy image, reduction of the image was observed in 5 patients, 3 out of which were evaluated as 'improved' or better. A distinctive reduction of ischemic regions was observed in 2 patients out of the 3. A significant decrease in the number of angina pectoris events and a decreasing tendency in consumption of fast-acting nitrates were observed in spite of the low number of the patients studied. An adverse effect was observed in 1 patient and abnormal laboratory values were observed in 2 patients which were improved promptly after withdrawal of the drug. It was in 7 patients evaluated as 'no problem', while in 4 patients it was evaluated as 'useful' or more. (author)

  10. Evaluation of viability of infarcted myocardium by low dose dobutamine stress echocardiography. Comparison with exercise stress 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    Exercise stress 201Tl myocardial single-photon emission computed tomography (SPECT) is recognized to be a excellent method for identifying viability after myocardial infarction, but it is expensive and needs a longer time for data acquisition than echocardiography. We therefore performed this study to evaluate the effectiveness of low dose (5-10 ?g/kg/min) dobutamine stress echocardiography (DSE) in 30 patients (61±8 years old: 24 men and 6 women) within 4 weeks after myocardial infarction in identifying viable myocardium, compared to results obtained by SPECT. Defining an akinetic or dyskinetic segment obtained by rest echocardiography as a definite infarct area, altogether 96 segments out of 716 segments were shown to be infarct areas. Of these, 75 (78%) segments were identified as viable by DSE, and 77 (80%) by SPECT. Only 2 segments were shown to be discrepant on DSE and SPECT. Subsequently, the sensitivity, specificity and accuracy rates for DSE were 96%, 100% and 96%, respectively. In conclusion, DSE is as effective and useful as SPECT in the evaluation of viability after myocardial infarction. (author)

  11. Gamma radiation measurements and Monte Carlo computations following myocardial perfusion imaging with 201Tl

    International Nuclear Information System (INIS)

    In the current study, the time-dependent retention of 201Tl-thallous chloride (111 MBq) was measured in a 56-y-old man undergoing myocardial perfusion imaging. For 23 d following the 201Tl injection, total-body retained activity was measured by (i) in situ gamma spectrometry using a portable high-purity germanium (HPGe) detector and (ii) ex vivo urine radioassay using a shielded HPGe detector. The time-dependent decrease in total-body activity followed a monoexponential function, exp(-0.011 t), with an excellent correlation (R2=0.9988) between the experimental data and the fitted values. The effective half-life, Teff, of 201Tl (physical half-life, Tph: 72.9 h) was therefore 63 h and the biological half-life, Tb, 463 h=19.3 d, identical to those measured in the same patient in 1997 (i.e. 14 y ago). The time-dependent decrease in the urine activity concentration, which followed a monoexponential function, exp(-0.0115 t), corroborated the foregoing results. The correlation (R2=0.9939) between the experimental data and the fitted values was again excellent. The effective half-life, Teff, was 60.26 h and the biological half-life, Tb, 348 h = 14.5 d. Monte Carlo simulation using a simple model of the patient as a unit-density cylinder filled with water and containing a uniform distribution of 201Tl yielded photon flux results in reasonable agreement with the measured data. (authors)

  12. Myocardial reversibility detection. Rest NTG 99mTc-MIBI versus 201Tl reinjection. Preliminary results

    International Nuclear Information System (INIS)

    This study test whether sublingual administration of nitroglycerin (NTG) could improve the capability of 99mTc-MIBI to detect reversibility in exercise-induced perfusion defects and to compare it with the 201Tl stress-redistribution-reinjection protocol. Twenty-one patients with previous myocardial infarction were submitted to exercise, rest and NTG rest 99mTc-MIBI imaging (3-day protocol). The patients also underwent exercise, redistribution and reinjection 201Tl myocardial scintigraphy. A total of 273 myocardial segments were analyzed: 76 (28%) had irreversible defects on stress-rest 99mTc-MIBI, 60 (79%) appeared as fixed defects and 16 (21%) were reversible on NTG rest 99mTc-MIBI. Of the 78 myocardial segments with irreversible defects on standard stress-redistribution thallium cardiac imaging, 63 (81%) did not change and 15 (19%) demonstrated enhanced uptake of thallium after reinjection. Data show that rest NTG 99mTc-MIBI study improves the detection of reversible myocardium versus standard exercise/rest 99mTc-MIBI and achieve similar results than 201TI reinjection protocol. (author)

  13. Behaviors of cost functions in image registration between 201Tl brain tumor single-photon emission computed tomography and magnetic resonance images

    International Nuclear Information System (INIS)

    We studied the behaviors of cost functions in the registration of thallium-201 (201Tl) brain tumor single-photon emission computed tomography (SPECT) and magnetic resonance (MR) images, as the similarity index of image positioning. A marker for image registration [technetium-99m (99mTc) point source] was attached at three sites on the heads of 13 patients with brain tumor, from whom 42 sets of 99mTc-201Tl SPECT (the dual-isotope acquisition) and MR images were obtained. The 201Tl SPECT and MR images were manually registered according to the markers. From the positions where the two images were registered, the position of the 201Tl SPECT was moved to examine the behaviors of the three cost functions, i.e., ratio image uniformity (RIU), mutual information (MI), and normalized MI (NMI). The cost functions MI and NMI reached the maximum at positions adjacent to those where the SPECT and MR images were manually registered. As for the accuracy of image registration in terms of the cost functions MI and NMI, on average, the images were accurately registered within 3 deg of rotation around the X-, Y-, and Z-axes, and within 1.5 mm (within 2 pixels), 3 mm (within 3 pixels), and 4 mm (within 1 slice) of translation to the X-, Y-, and Z-axes, respectively. In terms of rotation around the Z-axis, the cost function RIU reached the minimum at positions where the manual registration of the two images was substantially inadequate. The MI and NMI were suitable cost functions in the registration of 201Tl SPECT and MR images. The behavior of the RIU, in contrast, was unstable, being unsuitable as an index of image registration. (author)

  14. Thallium chloride 201Tl combined with single photon emission computed tomography (SPECT) in the evaluation of vestibular schwannoma growth

    DEFF Research Database (Denmark)

    Charabi, Samih Ahmed; Lassen, N A; Thomsen, J; Tos, M; Rossen, Karina Jervelund; Jacobsen, G K

    1997-01-01

    Thallium chloride 201Tl combined with SPECT was performed in a series of 29 patients with neuroradiological evidence of vestibular schwannoma (VS). The relative tumor uptake (U) and relative tumor concentration (C) of the radiotracer 201Tl was determined, and the cerebellum served as a reference. The relative tracer concentration and uptake were correlated to tumor volume determined by gadolinium DTPA enhanced MR, to prediagnostic duration of symptoms, to tumor vascularity expressed by the avera...

  15. Absolute quantitation of myocardial blood flow with 201Tl and dynamic SPECT in canine: optimisation and validation of kinetic modelling

    International Nuclear Information System (INIS)

    201Tl has been extensively used for myocardial perfusion and viability assessment. Unlike 99mTc-labelled agents, such as 99mTc-sestamibi and 99mTc-tetrofosmine, the regional concentration of 201Tl varies with time. This study is intended to validate a kinetic modelling approach for in vivo quantitative estimation of regional myocardial blood flow (MBF) and volume of distribution of 201Tl using dynamic SPECT. Dynamic SPECT was carried out on 20 normal canines after the intravenous administration of 201Tl using a commercial SPECT system. Seven animals were studied at rest, nine during adenosine infusion, and four after beta-blocker administration. Quantitative images were reconstructed with a previously validated technique, employing OS-EM with attenuation-correction, and transmission-dependent convolution subtraction scatter correction. Measured regional time-activity curves in myocardial segments were fitted to two- and three-compartment models. Regional MBF was defined as the influx rate constant (K1) with corrections for the partial volume effect, haematocrit and limited first-pass extraction fraction, and was compared with that determined from radio-labelled microspheres experiments. Regional time-activity curves responded well to pharmacological stress. Quantitative MBF values were higher with adenosine and decreased after beta-blocker compared to a resting condition. MBFs obtained with SPECT (MBFSPECT) correlated well with the MBF values obtained by the radio-labelled microspheres (MBFMS) (MBFSPECT = -0.067 + 1.042 x MBFMS, p 201Tl and dynamic SPECT. (orig.)

  16. Emission computed tomography using rotating gamma cameras for stress 201Tl myocardial imaging

    International Nuclear Information System (INIS)

    The purpose of this study is to evaluate the efficacy of emission computed tomography (ECT) for stress 201Tl myocardial imaging to localize coronary artery disease (CAD) in comparison with planar (PL) images. In a series of 14 normal subjects and 53 patients with CAD proved coronary arteriography, ECT and PL imaging were performed successively. ECT data were collected for 90 projections in a 64 x 64 matrix form with a total aquisition time of 6 munutes over 1800 of opposed dual cameras ratation and tomographic sections oriented perpendicular and parallel to the long axis of left ventricle were reconstructed. PL images were obtained for left lateral, left anterior oblique (300 and 450) and anterior projections. Both ECT and PL myocardial images were divided into 8 segments and segmental analysis was performed by visual interpretation. The ECT images remarkably increased sensitivity over the PL images in left anterior descending (LAD) artery (from 56% to 76%), right coronary artery (RCA) (from 50% to 96%), and circumflex artery (CX) (from 56% to 69%) lesions. The specificity for ECT images, as compared with PL images, was higher in LAD (88% against 85%) but slightly lower in RCA (70% ag ainst 72%) and CX (84% against 88%). Overall accuracy, therefore, was improved in LAD (from 67% to 81%) and RCA (from 64% to 79%) but equal in CX (81%). We conclude that stress 201Tl ECT imaging result in a remarkable improvement in the localization of CAD, especially in patients with RCA lesions and multi-vessel disease. (author)

  17. Influence of increased 201Tl lung uptake on the myocardial viability of the patients with dilated cardiomyopathy under congestive heart failure

    International Nuclear Information System (INIS)

    Influence of increased 201Tl lung uptake on the myocardial viability was studied in 15 patients with dilated cardiomyopathy under congestive heart failure. Rest and 4 hours delayed 201Tl SPECT were obtained. At the same time anterior planar images were collected. In 10 patients of 15 patients 201Tl lung heart ratio in SPECT (LHR) was larger than that in planar images. Maximal 201Tl lung uptake was noted at the lower left lung adjacent to the heart. In the delayed images 201Tl lung uptake diminished. In 10 patients the value of LHR in the delayed images was less than 0.5. By comparing initial images with delayed images it was proved to be difficult to determine the myocardial margin adjacent to the increased 201Tl lung uptake. In 2 patients lateral defects were concealed by the increased 201Tl lung uptake. In the remaining patients lateral wall was similar to the hypertrophic myocardium. The effect of scatter due to the increased 201Tl lung uptake was noted in the neighboring myocardium. In most cases %201Tl uptake in the septum was relatively depressed by increased %201Tl uptake in the lateral wall. In the delayed images pseudo-redistribution was noted in the septum. Mean value of differences in %201Tl uptake between initial and delayed images was 8(2-15)%. It was concluded that in case of increased 201Tl lung uptake SPECT could not accurately estimate myocardial viability by initial images and delayed images were necessary for precise estimation. (author)

  18. Myocardial imaging with 201Tl: an analysis of clinical usefulness based on Bayes' theorem

    International Nuclear Information System (INIS)

    Rest-exercise thallium-201 (201Tl) myocardial imaging and rest-exercise electrocardiography were performed in 137 patients with suspected coronary artery disease (CAD). The final diagnosis of coronary disease was made by arteriography. Sensitivity and specificity for the ECG and thallium studies alone or combined were then determined. Based on these data, the posttest probability of CAD with a normal or abnormal test was calculated using Bayes' theorem for disease prevalences ranging from 1% to 99%. The difference between the probability of disease with a normal test and the probability of disease with an abnormal test was also calculated for each prevalence range. The results demonstrate that 201Tl imaging discriminates between disease absence or presence better than does the ECG. However, both the ECG and thallium studies provide rather poor discrimination between disease and no disease when the disease prevalence is low (less than 0.20) or high (greater than 0.70). Because of this characteristic, it is unlikely that screening tests for CAD will prove useful unless the disease prevalence in the group under study is in the moderate (0.20 to 0.70) range

  19. Myocardial imaging with 201Tl at rest and during exercise. Comparison with coronary arteriography and resting and stress electrocardiography

    International Nuclear Information System (INIS)

    Myocardial imaging with intravenous thallium-201 (201Tl) was performed at rest and following maximal treadmill exercise in 101 patients with suspected coronary artery disease. Results were interpreted from Polaroid scintiphotos by three independent observers with complete interobserver agreement in 79%. Of 25 patients with no or insignificant coronary artery disease (201Tl image defect, one (4%) had an exercise 201Tl defect, none had an ECG Q wave, and four (16%) had exercise ST-segment depression. Among 76 patients with coronary artery disease (greater than or equal to 50% diameter stenosis), 58 (76%) had a defect on either the rest or exercise 201Tl image. The proportion of patients with an exercise image defect (50/76, 66%) was greater than the proportion with exercise ST depression alone (34/76, 45%; P 201Tl is easily accomplished with readily available imaging equipment. The image data enhanced the diagnostic sensitivity of stress electrocardiography, and provided spatial identification of the abnormal segment(s) of myocardium

  20. Crosstalk analysis of simultaneously acquired dual-isotope 201tl myocardial perfusion SPECT and 99Tcm-RBC equilibrium ventricle imaging

    International Nuclear Information System (INIS)

    Objective: To analysis the crosstalk between the 20'1Tl and 99Tcm while the myocardial SPECT imaging with 201Tl and the equilibrium ventricle imaging with 99Tcm-RBC are simultaneously acquired, and to search after a method to reduce the down scatter of 99Tcm in the 201Tl window. Methods: Myocardial perfusion images were acquired using a cardiac phantom, which can present various levels of ischemia. The pulse height analysis was performed before the SPECT acquisition. The down scatter ratio of different 201Tl doses was calculated on each project with variable acquisition energy window. After the raw data were reconstructed with Butterworth filter, the defect-to-myocardium count ratios from different 201Tl acquisition window and variable defect levels were compared. Results: During the dual-isotope acquisition with 201Tl and 99Tcm the main crosstalk was the down scatter of 99Tcm in 201Tl window, which was considerably reduced while using higher dosage of 201Tl. The down scatter was also inhibited by applying more specific energy window of 201Tl. The defect-to-myocardium ratio analysis showed that only the data acquired under 15% energy window were affected on the contrast of the defects in short axis slice. The window of 201Tl and the extent of the ischemia influenced the defect-to-myocardium ratios of mimic ischemia segments differently. The completely defect group appeared insensible to the change of acquisition window. Between the defect-to-myocardium ratio of 33% filled group and the 66% filled group considerable difference was demonstrated while the acquisition window of 20% was used. Conclusions: The down scatter of 99Tcm is the major factor which influences the simultaneous dual-isotope acquisition. The stain can be reduced either using more specific 201Tl energy acquisition window or applying higher dosage of 201Tl. But due to the long half-life of 201Tl, the authors can not increase the dosage discretionarily. As the more specific window of 201Tl can avoid the influence of the judgement of defect, and provide higher resolution of images, the authors recommend +-10% 201Tl energy window for 201Tl/99Tcm simultaneous acquisition

  1. Quantitative evaluation of right ventricular overload in cor pulmonale using 201Tl myocardial SPECT

    International Nuclear Information System (INIS)

    To determine quantitatively the discriminant and characteristics of cor pulmonale, 201Tl myocardial perfusion SPECT was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and 7 with restrictive pulmonary disease (RPD). One section of the short-axis SPECT image in which the right ventricle was most clearly visualized was selected. Tl-score was defined as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid, and posterior regions of the right ventricular free wall to the sum of counts in ROI at the posterior, lateral, and anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. In the group of COPD patients, Tl-score was positively correlated with mean pulmonary arterial pressure (mPAP), total pulmonary vascular resistance (TPR), and arterial carbon dioxide tension (PaCO2), while it was inversely correlated with arterial oxygen tension (PaO2). However, there was no significant correlation between Tl-score and mPAP, TPR, PaCO2, and PaO2 in the group of RPD patients. In assessing pulmonary hypertension as defined by mPAP over 20 mmHg, a Tl-score greater than 0.25 was useful with a sensitivity of 69% and a specificity of 90%. The occurrence of cor pulmonale is a major factor in determining the prognosis of COPD patients. It was concluded that 201Tl myocardial SPECT is useful for evaluating right ventricular overload quantitatively, as well as for assessing core pulmonale, especially in COPD patients, since the ratio of Tl counts in the right and left ventricles was significantly correlated with right cardiopulmonary hemodynamic parameters. (N.K.)

  2. Effects of diltiazem in patients with ischemic heart disease evaluation by exercise stress test and 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    In 15 ischemic heart disease patients including 6 with myocardial infarction, the effect of Diltiazem, a Ca-antagonist, was evaluated by exercise stress tests using an ergometer and by exercise stress 201Tl myocardial scintigraphy. Administration of Diltiazem significantly increased the exercise tolerance time from 6.6 +- 3.3 min. to 8.5 +- 3.2 min. (p 0.01). During exercise stress, heart rate was significantly decreased below the level of the controls and rate-pressure product, which is considered to be oxygen consumption index, was also decreased, while no significant change occurred in systolic pressure. Exercise stress 201Tl myocardial scintigraphy revealed some improvement of the defect in 5 of 8 cases. (Ueda, J.)

  3. Effect of wall thickness of left ventricle on {sup 201}Tl myocardial SPECT images. Myocardial phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Koto, Masanobu; Kawase, Osami [Kobe Univ. (Japan). Hospital; Namura, Hiroyuki; Yamasaki, Katsuhito; Kono, Michio

    1996-07-01

    {sup 201}Tl myocardial SPECT is known for better sensitivity, specificity, and accuracy than planar images in detecting coronary artery disease and diagnosing myocardial viability. SPECT images arc also superior to planar images in diagnostic sensitivity and anatomical orientation. However, as limitation of the spatial resolution of the machine, we often encounter poor SPECT plower image quality in patients with decreased wall thickness. To test the accuracy of SPECT images in patients with marked thinning of the left ventricular wall, as occurs in dilated cardiomyopathy, we performed a experimental study using myocardial phantom with 7 mm wall thickness. Tomographic image of the phantom images were rather heterogeneous, though no artificial defect was located Dilated cardiomyopathy is thought to be characterized by patchy defects in the left ventricle. Careful attention should be given to elucidating myocardial perfusion in patients with a thin left ventricle wall, as there are technical limitations in addition to clinical features. (author)

  4. Value of myocardial 201Tl scintigraphy for the diagnosis of coronary heart disease in patients with blocked left peduncle of His' bundle

    International Nuclear Information System (INIS)

    Possible use of loading myocardial 201Tl scintigraphy is considered for patients with blocked left peduncle of His' bundle. The procedure is shown to be of considerable value for the prognosis of coronary heart disease in such patients

  5. Myocardial scintigraphy using 99m-Tc-methoxyisobutylisonitrile (Tc-MIBI): A full substitution of 201-Tl?

    International Nuclear Information System (INIS)

    The results of selective coronary angiography, myocardial 201-Tl scintigraphy (stress and redistribution) and after 99m-Tc-methoxyisobutylisonitrile stress and rest injections (Tc-MIBI, Cardiolite, DuPont de Nemours, USA) were compared in 19 patients with manifest ischemic heart disease in identical three projections and after same ergometric load. 16 patients had significant stenoses of 1-3 main coronary arteries inclusive of left coronary artery main stem, insignificant stenoses (<50%) were present in the remaining 3 patients. Scintigraphic localizations of accumulation defects in both Tc-MIBI and 201-Tl stress scintigraphy were in agreement in 70.6% of evaluated left ventricular wall segments. A positive 201-Tl redistribution and rest-stress Tc-MIBI scintigraphic difference agreed in 52.6% of images of all three projections with verified accumulation defects. The sensitivity of ischemic area detection in reference to coronary angiography was nearly identical in 201-Tl (75%) and Tc-MIBI scintigraphy (81.2%). Better physical properties of 99m-Tc from the point of view of a gamma camera detection, a possibility to get markedly higher counting rate and sufficient accumulation of the radiopharmaceutical in the perfused myocardium enable to reach scintigraphic pictures with a high contrast after labelled Tc-MIBI injection, even in case of sequential impulse summation during heart cycle (gating). (author) 1 tab., 1 fig., 14 refs

  6. 201-Tl myocardial scintigraphy using SPECT. Clinical evaluation based on the Bayes' theorem

    International Nuclear Information System (INIS)

    The results of 201-Tl myocardial scintigraphy using SPECT were analyzed by means of the Bayes' theorem with respect to the positive and negative predictive value. A first evaluation was performed on a case by case basis with respect to the decision coronary heart disease (CHD) yes or no comprising the total number of patients. Furthermore two subgroups were formed a) patients with myocardial infarction or b) without. In the second part segmental findings of the leftventricular myocardium were analyzed applying the same subdivision. The values of the post-test-probability were calculated and plotted as a function of 2 parameters: 1) the pre-test-probability and 2) the outcome of the test. The maximum of the probability-difference-curve and thus the highest gain in diagnostic information was achieved with positive test results for medium pre-test-probability (about 50%). A prefered application of myocardial scintigraphy using SPECT therefore is the diagnosis of patients with a medium pre-test-probability of CHD as well as therapy planning and follow-up. (orig.)

  7. Improvement of myocardial perfusion detected by 201Tl scintigraphy on cardiac rehabilitation for patients with coronary artery disease

    International Nuclear Information System (INIS)

    The effect of cardiac rehabilitation (mean 70±48 months) on myocardial perfusion was assessed using thallium-201 (201Tl) exercise study in 63 patients with coronary artery disease (CAD). Subjects were those in a rehabilitation group (Rh=42) participating in supervised sports training two to three times per week and the control group (Ct=21) not taking active daily exercise. The interval between two 201Tl SPECT studies was 19±16 months. After physical training, total duration of the exercise test increased from 443±112 to 536±121 seconds (+19%) in the Rh group, and from 484±129 to 432±115 seconds in the Ct group (-10.7%) (p2 to 269.8±58 x 102 in the Rh group and decreased from 218.7±40 x 102 to 216.6±76 x 102 (p201Tl myocardial perfusion defect on exercise improved more in 54.8% (stress 59.5%, rest 35.7%) in the Rh group than in the Ct group (9.5%, p201Tl perfusion defect decreased from 68 (23.1%) to 49 regions (16.7%) of 294 total myocardial regions in the Rh group on exercise. However. it increased from 39 (26.5%) to 44 (29.9%) regions of 147 regions in the Ct group (p<0.01). Thus, cardiac rehabilitation increases exercise tolerance with improvement of myocardial perfusion. suggesting that cardiac rehabilitation is an advisable and effective treatment for patients with ischemic heart disease. (author)

  8. Evaluation of the graft flow reserve after coronary artery bypass grafting by stress {sup 201}Tl myocardial SPECT. Comparison between arterial grafts and venous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Akihiro; Taki, Junichi; Nakajima, Kenichi; Kawasuji, Michio; Tonami, Norihisa [Kanazawa Univ. (Japan). School of Medicine

    1997-01-01

    We performed stress {sup 201}Tl myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress {sup 201}Tl myocardial SPECT one month after CABG. Each patient`s myocardium was divided into 9 segments and visually evaluated using five grade scoring system (0=defect, 1=severe decrease, 2=moderate decrease, 3=mild decrease, 4=normal uptake). Eleven of 133 (8.27%) segments covered by patent venous grafts showed reversible {sup 201}Tl defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible {sup 201}Tl defect. This finding was observed more significantly in arterial grafts than in venous grafts (p<0.001). These finding suggests that arterial grafts have lower flow capacity than venous grafts at peak exercise. (author)

  9. Thallium chloride 201Tl combined with single photon emission computed tomography (SPECT) in the evaluation of vestibular schwannoma growth

    DEFF Research Database (Denmark)

    Charabi, Samih Ahmed; Lassen, N A

    1997-01-01

    Thallium chloride 201Tl combined with SPECT was performed in a series of 29 patients with neuroradiological evidence of vestibular schwannoma (VS). The relative tumor uptake (U) and relative tumor concentration (C) of the radiotracer 201Tl was determined, and the cerebellum served as a reference. The relative tracer concentration and uptake were correlated to tumor volume determined by gadolinium DTPA enhanced MR, to prediagnostic duration of symptoms, to tumor vascularity expressed by the average number of intratumoral vessels using the endothelial marker CD31, and to the proliferative activity in the tumors expressed by positive staining with the monoclonal antibody MIB-1 for Ki-67. A positive 201TI enhancement was detected in 17 tumors (n = 17). Tumors U and C were statistically unrelated to tumor volume (p = 0.236 and p = 0.439). SPECT demonstrated all tumors > 0.8 cm3, but it had its limitation as a diagnostic modality of small intracanalicular tumors, when compared with gadolinium DTPA enhanced MR. Relating U and C in all tumors (n = 29) and the prospectively registered data on the prediagnostic duration of symptoms, a statistical significance was found (p = 0.012 and p = 0.015). No statistically significant correlation was observed between U and C and the proliferative activity of the tumors expressed by positive staining with the monoclonal antibody MIB-1 for Ki-67 (p = 0.063 and p = 0.086). A statistically significant correlation was noted between C and U in the operated group (n = 12) and tumor vascularity expressed by the average number of the intratumoral vessels (p = 0.003 and p = 0.014). SPECT was found to be superior to MR in determining VS growth potentials as it expresses tumor vascularity, which is essential for tumor growth. It seems that we now have an in vivo functional radiological modality capable of providing data on VS vascularity and determination of growth potential in the individual tumor. A high radioactive tracer uptake in the tumor corresponded to high tumor vascularity, indicating a high growth rate and vice versa.

  10. Low-dose single acquisition rest {sup 99m}Tc/stress {sup 201}Tl myocardial perfusion SPECT protocol: phantom studies and clinical validation

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Thomas [RWTH Aachen University, Institute of Imaging and Computer Vision, Aachen (Germany); Backus, Barbra E.; Romijn, R.Leo [St. Antonius Hospital, Department of Nuclear Medicine, Nieuwegein (Netherlands); Wieczorek, Herfried [Philips Research, Eindhoven (Netherlands); Verzijlbergen, J.F. [St. Antonius Hospital, Department of Nuclear Medicine, Nieuwegein (Netherlands); Erasmus Medical Center, Department of Nuclear Medicine, Rotterdam (Netherlands)

    2014-03-15

    We developed and tested a single acquisition rest {sup 99m}Tc-sestamibi/stress {sup 201}Tl dual isotope protocol (SDI) with the intention of improving the clinical workflow and patient comfort of myocardial perfusion single photon emission computed tomography (SPECT). The technical feasibility of SDI was evaluated by a series of anthropomorphic phantom studies on a standard SPECT camera. The attenuation map was created by a moving transmission line source. Iterative reconstruction including attenuation correction, resolution recovery and Monte Carlo simulation of scatter was used for simultaneous reconstruction of dual tracer distribution. For clinical evaluation, patient studies were compared to stress {sup 99m}Tc and rest {sup 99m}Tc reference images acquired in a 2-day protocol. Clinical follow-up examinations like coronary angiography (CAG) and fractional flow reserve (FFR) were included in the assessment if available. Phantom studies demonstrated the technical feasibility of SDI. Artificial lesions inserted in the phantom mimicking ischaemia could be clearly identified. In 51/53 patients, the image quality was adequate for clinical evaluation. For the remaining two obese patients with body mass index > 32 the injected {sup 201}Tl dose of 74 MBq was insufficient for clinical assessment. In answer to this the {sup 201}Tl dose was adapted for obese patients in the rest of the study. In 31 patients, SDI and {sup 99m}Tc reference images resulted in equivalent clinical assessment. Significant differences were found in 20 patients. In 18 of these 20 patients additional examinations were available. In 15 patients the diagnosis based on the SDI images was confirmed by the results of CAG or FFR. In these patients the SDI images were more accurate than the {sup 99m}Tc reference study. In three patients minor ischaemic lesions were detected by SDI but were not confirmed by CAG. In one of these cases this was probably caused by pronounced apical thinning. For two patients no relevant clinical follow-up information was available for evaluation. The proposed SDI protocol has the potential to improve clinical workflow and patient comfort and suggests improved accuracy as demonstrated in the clinical feasibility study. (orig.)

  11. Low-dose single acquisition rest 99mTc/stress 201Tl myocardial perfusion SPECT protocol: phantom studies and clinical validation

    International Nuclear Information System (INIS)

    We developed and tested a single acquisition rest 99mTc-sestamibi/stress 201Tl dual isotope protocol (SDI) with the intention of improving the clinical workflow and patient comfort of myocardial perfusion single photon emission computed tomography (SPECT). The technical feasibility of SDI was evaluated by a series of anthropomorphic phantom studies on a standard SPECT camera. The attenuation map was created by a moving transmission line source. Iterative reconstruction including attenuation correction, resolution recovery and Monte Carlo simulation of scatter was used for simultaneous reconstruction of dual tracer distribution. For clinical evaluation, patient studies were compared to stress 99mTc and rest 99mTc reference images acquired in a 2-day protocol. Clinical follow-up examinations like coronary angiography (CAG) and fractional flow reserve (FFR) were included in the assessment if available. Phantom studies demonstrated the technical feasibility of SDI. Artificial lesions inserted in the phantom mimicking ischaemia could be clearly identified. In 51/53 patients, the image quality was adequate for clinical evaluation. For the remaining two obese patients with body mass index > 32 the injected 201Tl dose of 74 MBq was insufficient for clinical assessment. In answer to this the 201Tl dose was adapted for obese patients in the rest of the study. In 31 patients, SDI and 99mTc reference images resulted in equivalent clinical assessment. Significant differences were found in 20 patients. In 18 of these 20 patients additional examinations were available. In 15 patients the diagnosis based on the SDI images was confirmed by the results of CAG or FFR. In these patients the SDI images were more accurate than the 99mTc reference study. In three patients minor ischaemic lesions were detected by SDI but were not confirmed by CAG. In one of these cases this was probably caused by pronounced apical thinning. For two patients no relevant clinical follow-up information was available for evaluation. The proposed SDI protocol has the potential to improve clinical workflow and patient comfort and suggests improved accuracy as demonstrated in the clinical feasibility study. (orig.)

  12. Comparison of adenosine stress and exercise stress 201Tl myocardial perfusion imaging for diagnosis of coronary heart disease

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to compare the diagnostic values of adenosine and exercise stress 201Tl myocardial perfusion imaging for detecting coronary heart disease (CHD). Methods: 41 patients with suspected CHD were randomly divided into two groups. In one group adenosine stress was submitted, the exercise stress myocardial SPECT was performed in another. Coronary angiography (CAG) was performed in each patient within 2 weeks before or after SPECT. The result of CAG was taken as 'gold standard of CHD. They compared the diagnostic value of two methods. Results: In adenosine group, the sensitivity, specificity, positive predictive value, negative predictive value, accuracy are 92.86%, 57.14%, 81.25%, 80.00%, 80.95% respectively. In exercise stress group, are 100%, 60.0%, 71.43%, 100%, 80.00% respectively. Detection rates of coronary artery lesions were 66.67% and 72.22% in two groups respectively. Conclusion Adenosine stress testing and exercise stress testing 201Tl myocardial perfusion imaging may provide similar value for detection of CHD. (authors)

  13. Clinical implications of increased lung uptake of 201Tl during exercise scintigraphy 2 weeks after myocardial infarction

    International Nuclear Information System (INIS)

    To determine the prevalence and clinical significance of increased lung 201Tl uptake during submaximal exercise myocardial scintigraphy performed 2 weeks after acute myocardial infarction, 61 patients underwent submaximal exercise testing (target heart rate, 120 beats/min), multigated blood pool imaging at rest and coronary angiography before hospital discharge. Thallium lung uptake on the initial anterior projection image was graded qualitatively by comparing the intensity of 201Tl activity in the lungs with that in the mediastinum. In 39 patients (64 percent), it was normal (equal to mediastinal activity) and in 22 (36 percent), it was increased (greater than mediastinal activity). Compared with patients with normal lung uptake, those with increased uptake had a greater prevalence of prior infarction (13 versus 36 percent, probability [p] less than 0.05), less global cardiac reserve as assessed by the four level New York Heart Association classification (p less than 0.05), more advanced Killip class in the coronary care unit (p less than 0.05), a higher Norris coronary prognostic index (2.6 +/- 1.9 versus 4.6 +/- 2.3 [mean +/- standard deviation], p less than 0.01), failure to achieve the target heart rate because of dyspnea, fatigue or angina (36 versus 86 percent, p less than 0.01), a greater prevalence of exercise-induced S-T segment depression (18 versus 45 percent, p less than 0.05), a greater number of anterior 201Tl myocardial defects (p less than 0.05); a lower radionuclide ejection fraction at rest (50.4 +/- 6.1 versus 39.6 +/- 9.3 percent, p less than 0.01) and a greater number of asynergic left ventricular segments (p less than 0.05). Thus, the occurrence of increased lung 201Tl uptake during submaximal exercise scintigraphy in the early postinfarction period is frequent and appears to be a marker of severe and functionally more important coronary artery disease associated with left ventricular dysfunction

  14. Comparison of correction techniques for simultaneous {sup 201}Tl/{sup 99m}Tc myocardial perfusion SPECT imaging: a dog study

    Energy Technology Data Exchange (ETDEWEB)

    Knesaurek, Karin; Machac, Josef [Division of Nuclear Medicine, The Mount Sinai Medical Center, New York (United States)

    2000-11-01

    We compared two correction methods for simultaneous {sup 201}Tl/{sup 99m}Tc dual-isotope single-photon emission computed tomography (SPECT). Both approaches use the information from the third energy window placed between the photopeak windows of the {sup 201}Tl and {sup 99m}Tc. The first approach, described by Moore et al, corrects only for the contribution of the {sup 99m}Tc to the {sup 201}Tl primary 70 keV window. We developed the three-window transformation dual-isotope correction method, which is a simultaneous cross-talk correction. The two correction methods were compared in a simultaneous {sup 201}Tl/{sup 99m}Tc sestamibi cardiac dog study. Three separate acquisitions were performed in this dog study: two single-isotope and one dual-isotope acquisition. The {sup 201}Tl single-isotope images were used as references. The total number of counts, and the contrast between the left ventricular cavity (LVC) and the myocardium, were used in 70 keV short-axis slices as parameters for evaluating the results of the dual-isotope correction methods. Three consecutive short-axis slices were used to calculate averaged contrast and the averaged total number of counts. The total number of the counts was 667 000 {+-} 500 and 414 500 {+-} 400 counts for the dual-isotope ({sup 201}Tl + {sup 99m}Tc) and single-isotope ({sup 201}Tl-only) 70 keV images, respectively. The corrected dual-isotope images had 514 700 {+-} 700 and 368 000 {+-} 600 counts for Moore's correction and our approach, respectively. Moore's method improved contrast in the dual-isotope 70 keV image to 0.14 {+-} 0.03 from 0.11 {+-} 0.02, which was the value in the 70 keV non-corrected dual-isotope image. Our method improved the same contrast to 0.22 {+-} 0.03. The contrast in the {sup 201}Tl single-isotope 70 keV image was 0.28 {+-} 0.02. Both methods improved the 70 keV dual-isotope images. However, our approach provided slightly better images than Moore's correction when compared with {sup 201}Tl-only 70 keV images. (author)

  15. Assessment of myocardial viability by exercise stress myocardial tomography with 201Tl

    International Nuclear Information System (INIS)

    Exercise stress (Ex) and redistribution (RD) myocardial tomography with Tl-201 has been widely used for evaluating myocardial viability. But recent studies have demonstrated that reinjection (ReI) study following RD study is necessary for detecting reversible ischemic myocardium. On the other hand, decreased myocardial washout of Tl-201 after Ex is an indicator of myocardial ischemia. So we have studied the usefulness of myocardial Tl-201 washout rate (WOR) for the evaluation of myocardial viability by comparing it with ReI images. Ex and RD myocardial tomographies were obtained immediately after Ex and 3 hours later. After RD study a small amount of Tl-201 was injected and ReI imaging was repeated. We studied 64 myocardial segments (in 58 patients with coronary artery disease) in which Ex-induced perfusion defects persisted in RD images. According to the changes of perfusion defects between Ex, RD and ReI images, they were classified into 3 types: Type I; perfusion defect on the RD image was identical to ReI image (75%). Type I was divided into 2 subgroups whether perfusion defect at Ex was unchanged (Ia, 42%) or improved (Ib, 33%) on the RD image. Type II; perfusion defect at Ex was reduced on the RD image and it improved furthermore at ReI image (17%). Type III; perfusion defect was the same at Ex and RD but it was reduced on the ReI image (8%). WOR less than 30% was defined as abnormal when Ex heart rate exceeded 120 bpm and lung-myocardial Tl-201 uptake ratio was less than 0.45. The differentiation between Type Ia and Type III is of great importance. History of myocardial infarction, effort angina and Ex induced ST depression could not differentiate these 2 groups. WOR abnormality was observed in all of Type III, but WOR was normal in Type Ia. In conclusion, WOR abnormality in Ex-RD myocardial imaging is useful for evaluating myocardial viability. ReI imaging is necessary for the precise evaluation of viable muscle mass and for inadequate Ex. (author)

  16. [sup 123]I-MIBG myocardial scintigraphy in diabetic patients. Relationship with [sup 201]Tl uptake and cardiac autonomic function

    Energy Technology Data Exchange (ETDEWEB)

    Nagamachi, Shigeki; Jinnouchi, Seishi; Kurose, Takeshi; Ohnishi, Takashi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Shozo; Matsukura, Shigeru (Miyazaki Medical Coll., Kiyotake (Japan))

    1998-12-01

    The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by [sup 201]Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after [sup 123]I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of [sup 123]I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the [sup 201]Tl image and the [sup 123]I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score ([Delta]TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding [Delta]TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for [Delta]TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

  17. 123I-MIBG myocardial scintigraphy in diabetic patients. Relationship with 201Tl uptake and cardiac autonomic function

    International Nuclear Information System (INIS)

    The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by 201Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after 123I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of 123I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the 201Tl image and the 123I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score (?TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding ?TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for ?TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

  18. {sup 123}I-MIBG myocardial scintigraphy in diabetic patients. Relationship with {sup 201}Tl uptake and cardiac autonomic function

    Energy Technology Data Exchange (ETDEWEB)

    Nagamachi, Shigeki; Jinnouchi, Seishi; Kurose, Takeshi; Ohnishi, Takashi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Shozo; Matsukura, Shigeru [Miyazaki Medical Coll., Kiyotake (Japan)

    1998-12-01

    The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by {sup 201}Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after {sup 123}I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of {sup 123}I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the {sup 201}Tl image and the {sup 123}I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score ({Delta}TUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding {Delta}TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for {Delta}TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)

  19. Myocardial gammagraphy with 201Tl chloride in diagnosis of ischaemic heart disease

    International Nuclear Information System (INIS)

    In a group of 60 patients, the diagnostic reliability was compared of perfusion gammagraphy of the heart muscle with 201Tl chloride at exercise and of the ECG exercise test, with that of X-ray coronarography as the standard diagnostic method for ischaemic heart disease. The method of thallium perfusion gammagraphy of the heart muscle was as to its effectiveness very close to the method of standard diagnosis and its results in the diagnosis of ischaemic heart disease were significantly better than the results of the ECG exercise test. (author)

  20. Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of 201Tl gated SPECT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    In 201Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use 201Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest 201Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, ?5, summed rest score, SRS, 201Tl gated SPECT MPI. (orig.)

  1. Comparison study of left ventricular ejection fraction measured by 201Tl gated myocardial imaging and 99mTc-red blood cell gated blood-pool imaging

    International Nuclear Information System (INIS)

    Objective: To explore the correlation of automatic quantification of left ventricular ejection fraction (LVEF) from gated myocardial perfusion SPECT with 201Tl and rest equilibrium gated blood- pool imaging with 99mTc-red blood cell. Methods: Rest gated myocardial perfusion SPECT with 201Tl was performed on 72 cases. AUTOQUANT 4.21 software was used to measure LVEF. Rest equilibrium gated blood-pool imaging was also performed within 24 h. The values of LVEF measured by two methods were calculated and compared. Results: (1)There were strong correlation between the LVEF measured by rest gated myocardial perfusion SPECT and rest equilibrium gated blood-pool imaging(r=0.554, P=0.000). There was no significant difference between the two methods (t=1.194, P>0.05). (2) There was no significant difference between the two methods among different disease groups. (3) The values of LVEF measured by two methods were (64.68 ± 10.77)% and (62.46±8.99)%. The values of LVEF measured by gated myocardial perfusion SPECT was higher 3.55% than rest equilibrium gated blood-pool imaging. Conclusion: There was good correlation between the LVEF measured with gated myocardial perfusion SPECT by AUTOQUANT 4.21 software and gated blood-pool imaging. The LVEF can be accurately evaluated using gated myocardial perfusion SPECT with 201Tl. The value of LVEF measured by gated myocardial perfusion SPECT was higher than rest equilibrium gated blood-pool imaging. (authors)

  2. assessment of the clinical role of simultaneous 99mTc-MIBI and 201Tl dual-isotopic myocardial perfusion SPECT imaging in the patients wit hypertension

    International Nuclear Information System (INIS)

    Objective: To study the clinical role of Simultaneous rest technetium-99m sestamibi (99mTc-MIBI) and stress thallium-201 (201Tl) Dual-isotopic myocardial perfusion SPECT imaging in the patients with hypertension. Methods: 116 patients with high blood pressure underwent simultaneous dual-isotopic myocardial perfusion SPECT imaging with 99mTc-MIBI and 201Tl. 99mTc-MIBI was injected at rest, 15 min later dobutamine was instilled into vein begin with 5 mg/kg/min, before and after instilling the base ECG, blood pressure, heart rate was recorded. when the maximal dose of Dobutamine was achieved, thallium-201 was injected, the dual-isotopic simultaneously SPECT imagine was performed. The stress and rest imagine was obtained. After tomographic reconstruction, the images were interpreted by two experienced observers without previous knowledge of results of other studies. Coronary angiography was performed in two weeks. All of 116 patients were found normal. Results: (1) All of 116 patients with high blood pressure were divided as three group by the course of disease: A group (20 year), 15. The heart/lung ratios of A, B, C group were 2.651±0.246, 2.546±0.231, 2.490±0.36 (mean±SD)respectively, no significant difference was noted among three group. Normal heart/lung ratios is 2.50±0.28 among of control group of 20. (2) The overall sensitivity for the dual-isotopic simultaneously myocardial SPECT imagine of high blood pressure was 46.55%(54/116). (3) Anterior, lateral, inferior, apex, interventricular septal segment were regarded as a whole segment, 111 segments display abnormal 201Tl uptake. 63, 30, 18 segments were in A, B, C group respectively, and no significant difference was noted among three group. 4 85 segments reveal reduced stressing 201Tl uptake and no typical redistribution was observed in the delay 201Tl imagines. 20, 24, 14, 12, 15 segments were in anterior, lateral, inferior, apex, interventricular septal segment respectively. 26 segments display inverse 201Tl redistribution, 2, 14, 3, 3, 4 segments were m anterior, lateral, inferior, apex, interventricular septal segment respectively. 5 all rest 99mTc-MIBI imagines display normal uptake. Conclusion: Simultaneous rest 99mTc-MIBI and stress 201Tl dual-isotopic myocardial perfusion SPECT imaging is an effective auxiliary method in the detection of hypertension and identification of Coronary Artery Disease. (authors)

  3. Absolute quantitation of myocardial blood flow with {sup 201}Tl and dynamic SPECT in canine: optimisation and validation of kinetic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Hidehiro; Kim, Kyeong-Min; Nakazawa, Mayumi; Sohlberg, Antti; Zeniya, Tsutomu; Hayashi, Takuya; Watabe, Hiroshi [National Cardiovascular Center Research Institute, Department of Investigative Radiology, Suita City, Osaka (Japan); Eberl, Stefan [National Cardiovascular Center Research Institute, Department of Investigative Radiology, Suita City, Osaka (Japan); Royal Prince Alfred Hospital, PET and Nuclear Medicine Department, Camperdown, NSW (Australia); Tamura, Yoshikazu [Akita Kumiai General Hospital, Department of Cardiology, Akita City (Japan); Ono, Yukihiko [Akita Research Institute of Brain, Akita City (Japan)

    2008-05-15

    {sup 201}Tl has been extensively used for myocardial perfusion and viability assessment. Unlike {sup 99m}Tc-labelled agents, such as {sup 99m}Tc-sestamibi and {sup 99m}Tc-tetrofosmine, the regional concentration of {sup 201}Tl varies with time. This study is intended to validate a kinetic modelling approach for in vivo quantitative estimation of regional myocardial blood flow (MBF) and volume of distribution of {sup 201}Tl using dynamic SPECT. Dynamic SPECT was carried out on 20 normal canines after the intravenous administration of {sup 201}Tl using a commercial SPECT system. Seven animals were studied at rest, nine during adenosine infusion, and four after beta-blocker administration. Quantitative images were reconstructed with a previously validated technique, employing OS-EM with attenuation-correction, and transmission-dependent convolution subtraction scatter correction. Measured regional time-activity curves in myocardial segments were fitted to two- and three-compartment models. Regional MBF was defined as the influx rate constant (K{sub 1}) with corrections for the partial volume effect, haematocrit and limited first-pass extraction fraction, and was compared with that determined from radio-labelled microspheres experiments. Regional time-activity curves responded well to pharmacological stress. Quantitative MBF values were higher with adenosine and decreased after beta-blocker compared to a resting condition. MBFs obtained with SPECT (MBF{sub SPECT}) correlated well with the MBF values obtained by the radio-labelled microspheres (MBF{sub MS}) (MBF{sub SPECT} = -0.067 + 1.042 x MBF{sub MS}, p < 0.001). The three-compartment model provided better fit than the two-compartment model, but the difference in MBF values between the two methods was small and could be accounted for with a simple linear regression. Absolute quantitation of regional MBF, for a wide physiological flow range, appears to be feasible using {sup 201}Tl and dynamic SPECT. (orig.)

  4. 201Tl-myocardial SPECT - first experiences with a simultaneous transmission emission acquisition for non-uniform patient-related attenuation correction

    International Nuclear Information System (INIS)

    In this study our first clinical experiences with simultaneous transmission and emission acquisition in 201Tl myocardial SPECT (T/E-SPECT) are discussed. The non-uniform attenuation (AK) was carried out with a triple-head camera (PRISM 3000, Picker Inc.) correction equipped with fanbeam collimators. A line source of 750 MBq 99mTc was used to construct the transmission profile. Prior to investigation patients got 80-120 MBq 201Tl-chloride intraveneously injected. The study comprises the evaluation of 40 patients, derived from the clinical routine. The investigation followed an usual one day protocol. Our results using T/E-SPECT reveal an almost equilibrated activity distribution between anterior and posterior myocardial wall. For this reason it is to be expected that T/E-SPECT provides more reliable information about the posterior myocardial wall, than the usual SPECT technique without attenuation correction. (orig./MG)

  5. Quantified myocardial SPECT: Comparative evaluation of 201Tl-chloride and 99mTc-hexakis-(2-methoxy-isobutyl-nitrile) (RP 30) in coronary multivascular disorder

    International Nuclear Information System (INIS)

    Ten patients with multivascular coronary disorder were selected for the comparative SPECT examinations using 99mTc-RP 30 or 201Tl-chloride, under stress and at rest. Good agreement of myocardial uptake of the two substances was observed under stress, but there were deviations from the computed redistribution indexes of both substances. The redistribution index of myocardial regions supplied by stenosed coronary arteries was above 40 p.c. The results obtained so far show an equal, if not superior sensitivity of 99mTc-RP 30 SPECT as compared to the thallium compound, for detection of myocardial stress-induced ischemia. (orig./MG)

  6. Relationship between insufficient redistribution in exercise thallium-201 myocardial single-photon emission computed tomography and reverse redistribution at rest

    International Nuclear Information System (INIS)

    It is widely accepted that perfusion defects in 3 to 4-h delayed images in exercise thallium-201 (201Tl) myocardial scintigraphy underestimate the viability of myocardium in the infarct region. In the present study, to examine the contribution of the condition of myocardium which demonstrates reverse redistribution in resting scintigraphy to the insufficiency of redistribution in the 4-h delayed image in exercise scintigraphy, we performed exercise and resting 201Tl myocardial single-photon emission computed tomography in 58 patients with acute myocardial infarction and a single diseased coronary artery. Twenty eight patients demonstrated reverse redistribution (group RR) and 28 showed a fixed defect (group FD) in resting scintigraphy. Redistribution in the 4-h delayed image in exercise scintigraphy was significantly more insufficient in group RR than in group FD (p<0.01), and the degree of the insufficiency of redistribution in exercise scintigraphy closely correlated with the degree of reverse redistribution in resting scintigraphy (r=0.79, p<0.001). We conclude that in patients with acute myocardial infarction, the condition of myocardium which demonstrates reverse redistribution in resting myocardial scintigraphy is related to the insufficiency of redistribution in the delayed image in exercise scintigraphy. (author)

  7. Development and clinical application of an expert system for supporting diagnosis of 201Tl stress myocardial SPECT

    International Nuclear Information System (INIS)

    A consultation expert system which supports our computer aided reporting system was developed. The system was used for the evaluation of the two dimensional polar (bull's eye) display of 201Tl myocardial SPECT. The system consists of patients management (PM) and consultation expert systems (ES). The former is connected to image processors coupled with scinticameras. The bull's eye display of myocardial SPECT is transfered from image processor to the data base of PM. When inference request is made, the feature extraction program extracts information on localization, extent and severity of focal defects comparing count-rates pixel by pixel with the reference obtained from seven normal controls. The inference engine is activated to determine presence of focal defects utilizing diagnostic rules in the knowledge base. The results are sent back to PM and reported with the probability of assurance. Fifty eight patients with old myocardial infarction (OMI), angina pectoris (AP) and other diseases as well as normal controls were included in the study. The decision for presence or absence of focal defects by ES agreed with that by nuclear physicians (NP) in 301 segments among 330 (91%) in stress images. The presence of redistribution in delayed images agreed in 43 segments among 67 (64%). Image interpretation by ES agreed well with that of NP in patients with OMI (19/20) and AP (9/11). Seven were interpreted as normal by both ES and NP. The system is useful, as it provides NP with complementary and supportive information applicable to decision making and reporting. Further clinical experiences can improve knowledge base for better ES function. (author)

  8. Estimation of perioperative myocardial infarction in patients under aorto-coronary bypass grafts with plasma level of myosin light chain I and 201Tl SPECT

    International Nuclear Information System (INIS)

    After aorto-coronary bypass grafts surgery plasma level of myosin light chain I, determined with monoclonal antibodies to myosin light chain I (LC-I), were studied in 12 patients (pts) without electrocardiographical perioperative myocardial infarction. Rest 201Tl myocardial images were collected before and after surgery. LC-I increased and reached peak levels (15±7 ng/ml) at 91±29 minutes after the aortic declamp. From peak levels LC-I rapidly decreased with fast half-time disappearance (1.4±0.9 hours). In 5 pts of 12 pts LC-I recovered to normal range and MB reached maximum levels (34±23 IU/L) at 18±9 hours after declamp. In 4 pts 201Tl images showed no changes. In 7 pts of 12 pts LC-I decreased to minimum levels (2.7±0.6 ng/ml) at 12±6 hours and then gradually increased to peak levels (5.6±0.9 ng/ml) on day 3±0.9. MB reached maximum level (61±20 IU/L) at 3.2±1 hours. In 201Tl images 3 pts showed suspected new lesion, 2 pts showed no changes and 2 pts showed improvement. No correlation was noted between peak LC-I level and duration of aortic declamp. No significant relation was suspected between early LC-I peak and irreversible myocardial cell injury. From close relationship between aortic declamp and appearance of LC-I peak, it was concluded that LC-I, accumulated during aortic clamp, was washed out by aortic declamp. Relation was suspected between ealy LC-I peak and myocardial injury during myocardial protection. Late LC-I peak may be useful for estimation of perioperative irreversible myocardial injury. (author)

  9. Differential diagnosis of idiopathic congestive cardiomyopathy and ischemic heart disease by echocardiography and 201Tl-myocardial scintigraphy

    International Nuclear Information System (INIS)

    The usefulness of various non-invasive methods such as electrocardiography, echocardiography and 201Tl myocardial scintigraphy in the differential diagnosis of idiopathic congestive cardiomyopathy (CCM) and ischemic heart disease (IHD) were evaluated. Eighteen cases with CCM and 9 cases with IHD were subjected. For this study patients with IHD showing dilated cavity (LVDd over 66 mm) and diffuse hypokinesis of the left ventricle in the echocardiogram were selected. Cardiothoracic ratio of CCM and IHD were 59.6 +- 6.3% and 58.3 +- 6.3% in average, respectively. In CCM, mean LVDd was 76.0 +- 5.6 mm and mean LVDs was 63.4 +- 7.3 mm. In IHD, mean LVDd was 74.7 +- 8.1 mm and mean LVds was 63.2 +- 4.6 mm. Both cardiothoracic ratios and echocardiographic findings showed no difference between CCM and IHD. Incidence of an abnormal Q wave in ECG was higher in IHD (2.72 leads per a case) than that in CCM (1.33 leads per a case). An abnormal Q wave in aVL was frequently (28%) observed in CCM but none in IHD. However, these ECG findings did not seem to be contributory to the differential diagnosis. Myocardial scintigraphic study revealed that 10 of 18 cases with CCM showed no perfusion defect or sparse uptake and others showed small and isolated defect in the apex or postero-lateral wall of the left ventricle, while 7 of 9 cases with IHD showed large perfusion defect over 15% in the anterior and inferior areas. However, small localized defects less than 14% in the apex were observed in both groups, 5 cases (27.8%) with CCM, and 2 cases (22.2%) with IHD, suggesting limitation of this method for the differential diagnosis. (J.P.N.)

  10. Effect of long-term cholesterol-lowering treatment with HMG-CoA reductase inhibitor (Simvastatin) of myocardial perfusion evaluated by thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    Fifteen patients with either angina pectoris or old myocardial infarction, who had positive 201Tl single photon emission computed tomography (SPECT) imaging and coronary sclerosis of more than 50%, were treated with an HMG-CoA reductase inhibitor (simvastatin) for more than 1 year. They were compared with an untreated control group (n=25). Total cholesterol decreased 22% and high-density lipoprotein (HDL) increased 9% with simvastatin; both changes were significantly different from those in controls. Long-term simvastatin induced improvement of myocardial perfusion on 201Tl SPECT images both during exercise and at rest, which was also significantly different from controls. In addition, the improvement of myocardial perfusion on 201Tl SPECT images was clearly related to the improvements in cholesterol values, especially nonHDL cholesterol. Thus, the greater the decrease in nonHDL cholesterol, the greater the improvement in myocardial perfusion at rest or during exercise with long-term treatment using an HMG-CoA reductase inhibitor. These findings indicate that the improvements in cholesterol values caused by HMG-CoA reductase inhibitor therapy are related to improvements of myocardial perfusion seen on 201Tl SPECT images. (author)

  11. Clinical investigation of large perfusion defect cases with 201Tl exercise myocardial scintigraphy

    International Nuclear Information System (INIS)

    We investigated retrospectively the clinical significance of large perfusion defect on 201Thallium myocardial scintigraphy from the records of 833 patients during the past 3 years from 1991 to 1994. The patients were divided into 3 groups according to the extent of perfusion defect; cases with normal perfusion (n=561), with small perfusion defect (n=211) and with large perfusion defect (n=61). We found that the proportions of cases with large perfusion defect was significantly larger than that of cases with small perfusion defect in myocardial disease (MD; hypertrophic cardiomyopathy, dilated cardiomyopathy, and post myocarditis combined) (P201Thallium myocardial scintigraphy and that complication of diabetes mellitus and clinical symptoms may be useful in differentiating IHD from MD. (author)

  12. Quantitative analysis of exercise 201Tl myocardial emission CT in patients with coronary artery disease

    International Nuclear Information System (INIS)

    The clinical usefulness of quantitative analysis of exercise thallium-201 myocardial emission computed tomography (ECT) was evaluated in coronary artery disease (CAD). The subjects consisted of 20 CAD patients and five normal controls. All CAD patients underwent coronary angiography. Tomographic thallium-201 myocardial imaging was performed with a rotating gamma camera, and long-axial and short-axial myocardial images of the left ventricle were reconstructed. The tomographic images were interpreted quantitatively using circumferential profile analysis. Based on features of regional myocardial thallium-201 kinetics, two types of abnormalities were studied: (1) diminished initial distribution (stress defect) and (2) slow washout of thallium-201, as evidenced by patients' initial thallium-201 uptake and 3-hour washout rate profiles which fell below the normal limits, respectively. Two diagnostic criteria including the stress defect and a combination of the stress defect and slow washout were used to detect coronary artery lesions of significance (>=75 % luminal narrowing). The ischemic volumes were also evaluated by quantitative analysis using thallium-201 ECT. The diagnostic accuracy of the stress defect criterion was 95 % for left anterior descending, 90 % for right, and 70 % for left circumflex coronary artery lesions. The combined criteria of the stress defect and slow washout increased detection sensitivity with a moderate loss of specificity for identifying individual coronary artery lesion. A relatively high diagnostic accuracy was obtained using the stress defect criterion for multiple vessel disease (75 %). Ischemic myocardial volume was significantly larger in triple vessel than in single vessel disease (p < 0.05) using the combined criteria. It was concluded that quantitative analysis of exercise thallium-201 myocardial ECT images proves useful for evaluating coronary artery lesions. (author)

  13. Clinical studies on thallium-201 myocardial single-photon emission computed tomography in patients with ischemic heart disease

    International Nuclear Information System (INIS)

    In order to evaluate briefly the relative 3-dimensional distribution of 201Tl in the myocardium, a 2-dimensional polar map was developed from short axis tomograms of single-photon emission computed tomography (SPECT) using circumferential profile analysis. The data collected from 180 deg rotational scan around a body were used in clinical study to acquire the projection data in a short time, although, with a heart phantom study, there was more uniformity with the 360 deg collection than with 180 deg collection. So, the polar map of relative distribution and % washout rate (% WR) were created from 180 deg data collection. To detect ischemic area, the lower limit (M-SD) of the profile curve in 10 normal subjects was processed and compared with that of patients. Then, abnormal 201Tl distribution and % WR were identified comparing each patient's profile with the corresponding normal lower limits. In 24 patients with myocardial infarction, defect score (DS), estimated as infarcted size from the relative polar map, was compared with the size of abnormal wall motion in left ventriculography. There was a good correlation (r = 0.834) between them. Also, there were close correlations between DS and regional contraction (r = -0.869), and between DS and left ventricular ejection fraction (r = -0.775) respectively. In 24 patients with non-MI angina pectoris, the diagnostic sensitivity of exercise induced ischemia was 65 % and accuracy was 76 % by relative distribution map. However, the sensitivity of % WR map was superior (84 %) to that of relative map, especially in the patients with mild ischemia and multi-vessel disease. In conclusion, this comprehensive polar map method represented well a 3-dimensional myocardial distribution of 201Tl. The clinical usefulness in determination of infarct size and in diagnosis of myocardial ischemia were evaluated. (author)

  14. Quantitative analysis of 201Tl myocardial scintigraphy in ischemic heart disease

    International Nuclear Information System (INIS)

    Seventy two patients with myocardial infarction (MI), 13 with angina pectoris (AP), and 10 without ischemic heart disease were investigated by the quantitative analysis of Tl-201 myocardial scintigraphy. In the group of MI patients, defects of Tl-201 uptake was observed in 89.7% on planar images and 91.2% on SPECT images. Patients without Tl defect had no evidence of abnormal Q wave. For 62 patients undergoing coronary angiography and left ventriculography, defect size was well consistent with culprit lesions, particularly in the left anterior descending artery. Both extent score (ES) and severity score (SS), obtained by planar images and bull's-eye SPECT images, were significantly correlated with peak creatine phosphokinase (CPK) in plasma and ejection fraction. Redistribution magnitudes of Tl-201 uptake (?ES and ?SS) 3 hr after exercise were much greater in patients with exercise-induced ST depression than those with either unchanged or elevated ST segments. Some of the patients with no evidence of ST depression had high ?ES and ?SS. Similarly, these indices were high in patients with residual stenosis of culprit coronary artery. Six MI patients treated with percutaneous transluminal coronary angioplasty (PTCA) were found to have the decrease in both ?ES and ?SS. Decreased % Tl-201 uptake and % washout rate were also improved by PTCA. Similar improvement in these indices was seen in 15 AP patients successfully treated with PTCA. Reverse redistribution (RR) was seen in 5 patients with no significant stenosis of culprit coronary artery. Three other MI patients had also RR after PTCA. Areas corresponding to RR had higher washout rate than the other areas. In conclusion, quantitative analysis of Tl-201 myocardial scintigraphy seems to be useful in estimating infarction size and viable myocardium, as well as in evaluating the improvement of myocardial ischemia after PTCA. (N.K.)

  15. The evaluation of left ventricular eccentric hypertrophy by 201Tl-myocardial scintigraphy

    International Nuclear Information System (INIS)

    In order to elucidate the mechanism of left ventricular eccentric hypertrophy in conditions of volume overload, Tl-201 myocardial scintigraphy was performed in patients with aortic valve regurgitation and mitral valve regurgitation. There was a good relationship between the severity of Tl-defects, as determined by Tl-201 myocardial scintigraphy, and the changes in the T wave on the ECG on the one hand and the NYHA functional classification of heart diseases. In 17 of 18 patients where LVDd increased with increasing severity of Tl-defects and the defects were moderate to severe, LVDd was 65 mm or larger. There was a significant negative correlation between the washout rate for the whole circumference of the left ventricle, as determined by exercise Tl-201 SPECT, and LVDd (r=-0.603, p<0.01). The phenomenon of redistribution as determined by exercise Tl-201 myocardial scintigraphy was observed relatively early. Our results suggest that mechanical volume overload and ischemic changes are involved in left ventricular wall damage in left ventricular eccentric hypertrophy. For patients with moderate to severe Tl-defects valve replacement is indicated, no matter whether they may have heart failure or arrhythmia. (author)

  16. Quantitative evaluation of myocardial stress/rest 201Tl SPECT: Results of a ROI-based method in 108 patients with CHD

    International Nuclear Information System (INIS)

    ROI-based polar maps (33 ROIs) were employed to evaluate quantitatively stress/rest myocardial 201Tl SPECT in 108 patients with angiographically proven coronary heart disease (CHD) in comparison with 30 controls. Sensitivity in detecting a CHD with stenoses of > 50% of luminal diameter was determined versus normal regional values (± 2.5 SD) employing vitality (VI) and wash-out corrected redistribution (RD). The method was evaluated referring to the severity of the disease, to the number of ROIs displaying changes (a) 1 ROI, (b) > 2 ROIs, to validity of VI, RD or a combination thereof, and for specificity. Wash-out values were found to depend on degree of stress individually achieved and thus were not used as a threshold criterion. Sensitivity in supply areas with old myocardial infarctions was 95% (a) and 86% (b), resp. With no infarction, it was 96% (a) and 79% (b), resp. VI in stenosis > 75% was more sensitive than RD. However, combined evaluation of VI and RD yielded sensitivities from 91-100% (a) and 77-94% (b), resp. for different main supply areas. In stenosis 201Tl kinetics in myocardial SPECT, aimed at detecting and describing CHD. (orig.)

  17. Assessment of myocardial damage and metabolic disorder in the left ventricle in patients with mitral stenosis using {sup 201}Tl and {sup 123}I-BMIPP myocardial SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Kazuki; Tanabe, Takuji; Yuba, Tatsuya; Doue, Tomoki; Adachi, Yoshihiko; Katoh, Shuuji [Asahi Univ., Gifu (Japan). Murakami Memorial Hospital; Sugihara, Hiroki; Azuma, Akihiro; Nakagawa, Masao

    2001-07-01

    This study was designed to evaluate the myocardial damage and metabolic disorder of the left ventricle in patients with mitral stenosis. We studied 15 patients with mitral stenosis. Their grade of chronic heart failure using New York Heart Association classification were class I: 5 patients, class II: 5, class III: 3, class IV: 2, respectively. The severely stenotic group (valve area <1.5 cm{sup 2}) included 6 patients, mildly stenostic group (1.5 cm{sup 2}{<=} valve area <2.5 cm{sup 2}) included 9. A 111 MBq of {sup 123}I-BMIPP was intravenously injected at rest, SPECT images were obtained at 15 min and 3 hours after injection. A 111 MBq of {sup 201}Tl was intravenously injected at rest, and SPECT images were obtained at 15 min after injection. Washout rate (WR) of {sup 123}I-BMIPP from the whole left ventricle was obtained using polar maps. The concentration of norepinephrine (NE: pg/ml) in the blood at rest was measured. The mean values of pulmonary artery pressure was measured in ten patients using Swan-Ganz catheter. {sup 123}I-BMIPP myocardial SPECT and measurement of NE were reexamined in 5 patients after mitral valvuloplasty. NE values were 476{+-}72 and 793{+-}286 in classes I+II and III+IV, respectively. NE values was increased in the severe heart failure group (p<0.05). NE values were 480{+-}69 and 743{+-}295 in the mildly and severely stenotic groups, respectively. NE value was increased in severely stenotic group (p<0.05). Twelve patients showed normal uptake on both {sup 201}Tl and {sup 123}I-BMIPP myocardial SPECT. Three patients showed slightly reduced uptake on both {sup 201}Tl and {sup 123}I-BMIPP myocardial SPECT. WR was 27.2{+-}4.8% and 44.3{+-}6.7% in class I+II and class III+IV, respectively. WR was increased in severe heart failure group (p<0.05). WR was 27.8{+-}6.0% and 41.3{+-}9.4% in the mildly and severely stenotic group, respectively. WR was increased in the severely stenotic group (p<0.05). NE was correlated with WR (p<0.001). In patients with mitral valvuloplasty, WR was 44.3{+-}6.7% and 31.4{+-}4.7% before and after mitral valvuloplasty, respectively. NE values were 857{+-}266 and 574{+-}165, respectively. Both WR and NE were decreased after mitral valvuloplasty (p<0.01). In patients with mitral stenosis, WR was increased in the severe heart failure group and severely stenotic group without apparent myocardial damage. Myocardial metabolism in the left ventricle might be influenced by right heart failure through, for example, NE and neurohormonal factors. (author)

  18. Results of RNV studies and 201Tl myocardial scintigraphy in patients with progressive systemic scleroderma (PSS)

    International Nuclear Information System (INIS)

    Prognosis of progressive systemic scleroderma (PSS) depends directly on the extent of visceral organ involvement, and in particular, on the cardiac, renal and pulmonary appearance. Therapeutic approaches therefore require periodic followup with non-invasive methods to evaluate the actual course of disease and the success of therapy. Tl-201 scintigraphy showed pathologic heart abnormalities in 47% and RNV in 23% of the PSS patients. Our results and published data reveal the sensitivity of both myocardial scans and RNV in the evaluation of patients with PSS. Other current methods for the diagnosis of heart diseases, however, such as echocardiography should also be performed. In patients with PSS coronary angiography, however, usually shows normal coronary vessels. (orig.)

  19. Importance of 201Tl scintigraphy during exercise for diagnosis of silent myocardial ischemia

    International Nuclear Information System (INIS)

    Using thallium scintigraphy during exercise (TSE), suspect silent myocardial ischemia (SIM) was diagnosed in subjects without angina pectoris. 21 active pilots with suspect SIM were examined after previous exercise ECG as well as 33 patients with diabetes type I and II. In six pilots (28.6%) TSE showed accumulation defects suggesting ischemic disorders of the large coronary arteries. Five pilots showed obvious depressions of the ST segment in ECG during submaximal exercise TSE. In another group of five pilots small depressions of the ST segment were associated with normal TSE. Twelve diabetic patients (36.4%) had minor accumulation defects on TSE. Only two showed a ST depression under 2 mm in ECG during TSE. Based on data in the literature suggesting higher sensitivity and specificity of exercise thallium scintigraphy as compared with exercise ECG and the possibility of a false positive diagnosis of SIM from exercise ECG alone, it is recommended to also use TSE. A more detailed diagnosis of SIM is essential not only with regard to the assessment of work capacity but also for a long-term follow-up of patients with SIM for assessment of its incidence, impact and prognosis in the population. (author). 4 figs., 4 tabs., 25 refs

  20. Dual myocardial scintigraphic imaging using 123I-BMIPP and 201Tl in patients with Duchenne's progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Dual single photon emission computed tomography (SPECT) was performed in 30 patients with Duchenne's muscular dystrophy (DMD) using 201 thallium (Tl) for myocardial perfusion 123I-?-methyl-p-iodophenylpentadecanoic acid (BMIPP) for myocardial fatty acid metabolism scintigraphy. The left ventricle was divided into 9 regions, and accumulation of the radiotracers was assessed visually for each region to calculate defect score for each tracer. There was some degree of decrease in the myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP, 70%; Tl, 63%), followed by the posterior wall, lateral wall, and anterior wall. It was less common on the apical side of the ventricular septum for both tracers (BMIPP, 3%; Tl, 17%). Accumulation of Tl was lower than BMIPP in 18/30 patients (60%) and higher in 9 (30%), while both tracers showed equal accumulation in 3 (10%). BMIPP showed higher accumulation than Tl in all regions but the septum. A significant negative correlation was found between the defect scores for both tracers and the left ventricular ejection fraction (LVEF) (r=-0.629 for Tl; r=-0.567 for BMIPP). The strongest negative correlation was that between the sum of the Tl and BMIPP defect scores and the LVEF (r=-0.681). Dual SPECT myocardial scintigraphy with Tl and BMIPP provided an accurate evaluation of the progression of cardiac lesions in DMD by detecting abnormalities of the myocardial metabolism of each substance thereby enabling the assessment of left ventricular function. (author)

  1. Exercise and rest myocardial scintigraphy with 201TlCl/99mTc-MIBI dual energy acquisition using triple-energy window scatter correction

    International Nuclear Information System (INIS)

    We carried out dual 201Tl/99mTc-MIBI imaging to reduce the time required for exercise myocardial scintigraphy. We investigated 4 different protocols. In protocol (A), Tl was injected at rest followed by the injection of MIBI at peak exercise. Dual SPECT images were obtained by 201Tl/99mTc simultaneous acquisition. Protocol (B) means reverse either, in which MIBI was injected at rest followed by the administration of Tl at peak exercise. In protocol (C), exercise was performed first with MIBI-injection, and then Tl was injected at rest one hour later. Simultaneous acquisition was also performed. In protocol (D), after the rest Tl-imaging, MIBI was injected at peak exercise, and then the MIBI-imaging was done. In protocol (A), (B) and (C), simultaneous acquisition was performed using TEW (Triple-Energy Window) scatter correction. Thanks to using dual isotopes, all procedures could be completed within 1-2 hours, which was much shorter than the conventional myocardial perfusion imaging. Scatter correction was useful for accurate diagnoses, when the simultaneous imaging is performed. (author)

  2. Role of ultrashort-lived radionuclides in cardiovascular studies: /sup 195m/Au ventriculography and simultaneous 201Tl myocardial imaging

    International Nuclear Information System (INIS)

    The advantages of ultrashort-lived radionuclides (USRN's) are multiple: (1) bedside production, (2) reduction of patient radiation exposure, (3) possibility of administering larger doses of radionuclides, (4) multiple, rapid, sequential, background-free studies, and (5) multiple, simultaneous radionuclide administrations. Simultaneous injection of thallium-201 and gold-195m at maximal exercise and at rest in 24 patients with coronary artery disease (CAD) are described. A bolus of approximately 20 mCi of /sup 195m/Au was followed 1 or 2 sec later by 2 mCi of thallium-201. During the first 25 sec, imaging of first-pass ventriculography was performed in the 260-keV window. Five minutes later /sup 195m/Au had decayed, and conventional planar imaging of 201Tl was performed. Sensitivity for diagnosis of CAD in stress first-pass radionuclide ventriculography was 83%, of wall motion 79%, and 201Tl stress myocardial perfusion was 83%. It was concluded that first-pass ventriculography and simultaneous myocardial perfusion determinations (1) are feasible procedures and (2) appear to offer the possibility of a high-sensitivity and high-specificity test for coronary artery disease

  3. Aspects of recovery from regional wall motion abnormalities after exercise in patients with ischemic heart disease using 201Tl myocardial dynamic SPECT

    International Nuclear Information System (INIS)

    Using 201Tl myocardial dynamic SPECT (dynamic SPECT), we studied various aspects of the recovery from exercise-induced ischemia, particularly the mechanism of delayed recovery from wall motion abnormality. The subjects were 23 patients with ischemic heart disease who underwent coronary angiography, exercise stress two-dimensional echocardiography (ESE), and dynamic SPECT. Using a 3-head SPECT system, dynamic SPECT was performed for 33 min consecutively from 5 min after the intravenous injection of 201TlCl (Tl). The regional early washout rate (early WR) was determined at 20, 29, and 38 min after Tl injection, and the delayed washout rate (delayed WR) was determined at 240 min. From the duration of regional wall motion abnormalities on ESE, the patients were divided into Group A (wall motion abnormalities persisting for ?20 min, n=8) and Group B (<20 min, n=15). At each point of assessment, early WR was significantly lower in Group A than in the control group (5 healthy subjects) and Group B (p<0.01). In addition, the early WR at 20 min was negative in all Group A patients. The present study suggests that a persistent relative and reduction in myocardial blood flow is one factor responsible for prolonged abnormal regional wall motion. (author)

  4. Diagnostic accuracy of supine and prone thallium-201 stress myocardial perfusion single-photon emission computed tomography to detect coronary artery disease in inferior wall of left ventricle

    International Nuclear Information System (INIS)

    Prone thallium-201 (201Tl) myocardial perfusion single-photon emission computed tomography (SPECT) reduces false-positive rates when evaluating inferior wall abnormalities by minimizing diaphragmatic attenuation. The present study investigates the diagnostic validity of prone 201Tl stress myocardial perfusion SPECT for detecting coronary artery disease in the inferior wall of the left ventricle in Japanese patients. Of the 104 consecutive patients who underwent 201Tl stress myocardial perfusion SPECT to diagnose coronary artery disease, we evaluated 46 who underwent image acquisition in both the supine and prone positions, and coronary angiography within 3 months thereafter. Images were acquired in the routine supine position immediately following 201Tl (111 MBq) injection and 4 h following early acquisition. Images were acquired in the prone position only during the early phase following supine acquisition. We evaluated the SPECT images of the inferior half segments of the left ventricle using a five-point defect scoring system. According to the coronary angiographic findings, we investigated the diagnostic accuracy of stress-rest supine, stress supine, stress prone, and combined supine-prone images. Reduced uptake in the stress supine image of the combined images was considered as attenuation when uptake was normal in the prone image. The sensitivity of the stress-rest supine, stress supine, stress prone, and stress-combined supine-prone images was 77%, 86%, 55%, and 55%, and the specificity was 71%, 54%, 79%, and 83%, respectively. Diagnostic accuracy was the highest in stress-rest supine images. Prone images tended to improve the specificity of detecting coronary artery disease in the inferior wall, but not diagnostic accuracy compared with stress-rest supine images because of decreased sensitivity. (author)

  5. Precision of electrocardiographic diagnosis of myocardial infarction in the ventricular septal area. Comparison with 201-TlCl scintigraphy and coronary angiography

    International Nuclear Information System (INIS)

    The purpose of this study was to clarify the diagnostic accuracy of 3 electrocardiographic (ECG) indexes including Q waves in V1[QV1(+)], Q waves in V1 and V2 [QV1V2(+)], and absence of septal q waves in V6 [qV6(-)] for prediction of myocardial infarction (MI) in the interventricular septal area (IVS) using 201-TlCl myocardial scintigraphy. In addition, we also evaluated the relationship between these ECG indexes and the site of the culprit lesions in the left anterior descending artery (LAD). This study consisted of 115 patients (100 males; mean age, 60 years) with anteroseptal MI who underwent 201-TlCl myocardial scintigraphy in our hospital between January 1994 and December 1997. One hundred six of them also underwent coronary angiography (CAG). On extent maps obtained from SPECT images of 201-TlCl scintigraphy, the area of MI occupying the IVS area, using the proportion of the defect area in the IVS, was expressed as % defect area (%DA). Three patterns of %DA were defined as follows. A: 50%?%DA?100%; B: 70%?%DA?100%; and C: 90%?%DA?100%. On scintigraphic evaluations, %DA in patients with each of the 3 ECG indexes was significantly larger than %DA in patients without them (p=0.0002, p=0.0008, and p=0.0008, respectively). QV1(+) and qV6(-) showed good sensitivities only for pattern C (79% and 75%, respectively), but all ECG indexes showed low sensitivities for patterns A and B. Regarding specificity, QV1V2(+) showed the best values (76% for pattern A, 68% for pattern B, and 68% for pattern C) among the 3 ECG indexes. For prediction of the culprit lesions located proximal to the origin of the first septal branch, qV6(-) showed a relatively good sensitivity (67%) and specificity (67%). For prediction of MI in the IVS area, QV1(+) and qV6(-) showed good sensitivities when the MI was sufficiently large in size. QV1V2(+) showed relatively good specificities irrespective of the MI size. qV6(-) was the best predictive index for the culprit lesions located in the proximal site of the LAD. (author)

  6. Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of {sup 201}Tl gated SPECT myocardial perfusion imaging

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    Chen, Chien-Cheng; Shen, Thau-Yun [Show Chwan Memorial Hospital, Department of Cardiology, Changhua (China); Chang, Ming-Che [Changhua Christian Hospital, Department of Nuclear Medicine, Changhua (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Wan-Chen [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Changhua (China); Kao, Chia-Hung [China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China); Chen, Ji [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States)

    2012-12-15

    In {sup 201}Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use {sup 201}Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony. Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest {sup 201}Tl gated SPECT MPI. The early post-stress scan was started 5 min after injection, and followed by the rest scan 4 h later. The patients were divided into three groups: ischemia group (N = 25, summed stress score, SSS, {>=}5, summed rest score, SRS, <5), infarct group (N = 16, SSS {>=}5, SRS {>=}5) and normal group (N = 34, SSS <5, SRS <5). LV dyssynchrony parameters were calculated by phase analysis, and compared between the stress and rest images. In the ischemia group, LV dyssynchrony was significantly larger during stress than during rest. On the contrary, LV dyssynchrony during stress was significantly smaller than during rest in the normal and infarct groups. LV dyssynchrony during rest was significantly larger in the infarct group than in the normal and ischemia groups. There were no significant differences in LV dyssynchrony during rest between the normal and ischemia groups. Stress-induced myocardial ischemia caused dyssynchronous contraction in the ischemic region, leading to a deterioration in LV synchrony. Normal myocardium had more synchronous contraction during stress. The different dyssynchrony pattern between ischemic and normal myocardium early post-stress may aid the diagnosis of coronary artery disease using {sup 201}Tl gated SPECT MPI. (orig.)

  7. Clinical significance of diffuse slow washout pattern (DSWO) on the exercise stress 201Tl SPECT myocardial imaging: Correlative study with influencing factors

    International Nuclear Information System (INIS)

    DSWO shown on the Bull's eye images was found in 98 of 1234 patients suspected of having coronary artery disease and examined with 201Tl myocardial SPECT imaging. 48 of these 98 patients underwent coronary arteriography. Comparison studies were performed between Bull's eye SPECT image, coronary arteriography and laboratory data. DSWO was found in 11 cases with single vessel disease (1VD), 18 cases with double vessel disease (2VD) and 21 cases with triple vessel disease (3VD). Three of 58 cases with stenosis of a cardiomyopathy. In the CAD group, DSWO appeared frequently accompanying hypertension, hyperlipemia and diabetes mellitus. These complications tended to increase in patients with 1VD and the stenosis less than 75%

  8. 201Tl labelled myocardium tomoscanning

    International Nuclear Information System (INIS)

    A new device, the J and P Tomoscanner, enables us to obtain the transverse scintigraphic section of any organ labelled by a single photon emitting radionuclide. For the time being, this technique has been used mainly for brain and liver studies. This work explores the ability of this tomograph to furnish sections of the 201Tl labelled myocardium by comparing them with the scintillation gamma-camera images. Towards this aim, witnesses and patients with documented anterior or lateral infarctus have been studied. Our actual results show a high correlation between the two explorations. But, by means of the section, both the site and size of the necrosis are visualized. However, only a single tomographic image was obtained in each patient because of the time necessary for its retranscription on paper. In the near future, when it will be possible to perform routinely several sections, a better size estimation will be possible

  9. Quantitative rotational tomography with 201Tl and 99mTc 2-methoxy-isobutyl-isonitrile. A direct comparison in normal individuals and patients with coronary artery disease

    International Nuclear Information System (INIS)

    We tested the hypothesis that 99mTc 2-methoxy-isobutyl-isonitrile (99mTc MIBI), a new radiopharmaceutical for myocardial perfusion imaging, provides accurate noninvasive detection of coronary artery disease (CAD). Imaging in patients after exercise and at rest with 99mTc MIBI was compared with imaging after exercise and redistribution with 201Tl in 12 normal subjects and 38 patients with angiographic documentation of CAD (greater than or equal to 50% diameter stenosis). We used single-photon emission computed tomography (SPECT) and computer quantitation of regional tracer distribution. The quality of reconstructed images with 99mTc MIBI judged visually was superior to that of 201Tl in 88% of all studies performed and was comparable in the others. With the limits of normal as 2.5 SD below the mean of gender-matched normal volunteers, 201Tl SPECT identified 32 and 99mTc MIBI identified 36 patients with CAD (p = 0.2). 201Tl SPECT identified 45 of 75 (60%) and 99mTc MIBI identified 59 of 75 (79%) stenosed coronary arteries (p less than 0.05). The quantitative severity of perfusion defects was similar for the two tracers. 201Tl SPECT identified 104 reversibly ischemic myocardial segments compared with 134 with 99mTc MIBI (p less than 0.05). Thus, SPECT myocardial perfusion imaging with 99mTc MIBI and computer quantitation provides an accurate method for the noninvasive detection of significant coronary artery disease. Furthermore, image quality is generally superior to 201Tl, and reversibly ischemic myocardial segments may be better identified with 99mTc MIBI

  10. Acute and reperfused myocardial infarction: relations between 'reverse redistribution' of 201Tl at rest, micro-perfusion and myocardial viability

    International Nuclear Information System (INIS)

    The mechanism of 'reverse redistribution' (RR) of thallium after myocardial infarction remains obscure. In fact, the fixation of thallium depends on the coronary flow rate, microcirculation and cellular viability. We have studied the RR in 18 patients with normal coronary flow rate after reperfusion of artery of acute phase infarction but with a large range of micro-circulation alteration (evaluated by intracoronary contrast echography (ICCE)) and necrosis size. A thallium rest-redistribution achieved at the eighth day (8D) and 42D was compared with a perfusion score established by ICCE and analyses of the echographic regional kinetics achieved at 0D, 8D and 42D. At 8D a RR was observed in 16/18 patients with a 15 minute average defect of 25 ± 15% of myocardium extended up to 34 ± 13% at 4 hours. At 42D only 6/18 patients retained a RR while the average changes in the size of defect were not significant. The defect measured at 8D on the 15 min. image alone showed to be significantly correlated with the perfusion score while the patients with bad micro-perfusion had defects significantly larger than the others. On the other side the size of the same defect at 15 min. showed to be correlated to that of redistribution at 42D as well as the number of the akinetic segments at 42D. In conclusion, a large a RR is present at 8D after acute reperfusion of a myocardial infarction and tends to vanish at 42D. The 15 minute images reflect essentially the micro-perfusion. The last one being a necessary condition of myocardial salvation, the size of the 15 minute defect is also correlated to the viability indices evaluated at 42D

  11. Impaired coronary flow reserve is the most important marker of viable myocardium in the myocardial segment-based analysis of dual-isotope gated myocardial perfusion single-photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Woo [Dept. of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); So, Young [Dept. of Nuclear Medicine, Konkuk University School of Medicine, Seoul (Korea, Republic of); Kim, Ki Bong; Lee, Dong Soo [Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-04-15

    The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), {sup 201}Tl perfusion status at rest, {sup 201}Tl 24 hours redistribution and systolic wall thickening of {sup 99m}Tc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 ± 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. The left ventricular ejection fraction (LVEF) significantly increased from 37.8 ± 9.0% to 45.5 ± 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and {sup 201}Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.

  12. Quality control 201TlCl solution obtained at IPEN-CNEN/SP through the direct method of 201Tl preparation

    International Nuclear Information System (INIS)

    The radiopharmaceutical 201TlCl is used in Nuclear medicine for myocardial visualization. The solution of 201TlCl was prepared using 201Tl obtained by irradiating a natural mercury target with protons. This radionuclide was subjected to different quality control processes to verify the purity required for its use in Medicine. Some of these controls concerned the determination of 200Tl, 201Tl and 202Tl; the chemical identification of 201Tl+1; the hydrazine concentration, mercury contamination and the presence of phosphate. Furthermore, the biologic distribution in Wistar rats and tests for sterility, pyrogens and for toxicity were carried out. It was verified that the solution obtained was in the form of thallous chloride. This radiopharmaceutical can give a good heart image in animals but due to the contamination of 201Tl with 200Tl and 202Tl its use in human beings is not possible unless enriched 202Hg is used as target of irradiation. (author)

  13. Relation between myocardial damage and disease activity in patients with systemic lupus erythematosus by exercise {sup 201}Tl scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Kuzumoto, Masayuki [Nara Medical Univ. (Japan)

    1997-08-01

    Myocardial damage in patients with systemic lupus erythematosus (SLE) was evaluated using exercise thallium-201 myocardial scintigraphy, and the relationship between myocardial damage and disease activity of SLE was examined. Twenty-seven patients (26 women and 1 man, mean age 43 years), in whom extramural coronary artery lesions were excluded by coronary angiogram or presumed to be excluded by exercise electrocardiogram, were enrolled in this study. The mean duration of disease and the mean duration of corticosteroid therapy in these patients were 94 and 77 months, respectively. Exercise thallium-201 scintigraphy was performed twice (mean interval, 30 months) to evaluate the progression of myocardial damage. Myocardial ischemia as an index of myocardial damage was evaluated by visual analysis and ischemic score (IS). The changes in myocardial ischemia were categorized into 3 groups: improved, unchanged or worsened. The disease activity of SLE was determined by the SLE Disease Activity Index (SLEDAI), and the changes in this index were classified into the same three categories, as evaluated every six months between the two scintigraphic examinations. Disease activity was significantly correlated with myocardial ischemia (p<0.05), and with myocardial ischemia as diagnosed by {Delta}IS (difference in ischemic score between the first and second thallium-201 scintigrams: p<0.005). But neither the duration of disease nor the duration of corticosteroid therapy was correlated with IS at the first scintigraphy. These results indicate that control of SLE disease activity may be critical in the treatment of myocardial damage resulting from vascular lesions, especially intramyocardial small-artery disease, in patients with SLE. (author)

  14. Relation between myocardial damage and disease activity in patients with systemic lupus erythematosus by exercise 201Tl scintigraphy

    International Nuclear Information System (INIS)

    Myocardial damage in patients with systemic lupus erythematosus (SLE) was evaluated using exercise thallium-201 myocardial scintigraphy, and the relationship between myocardial damage and disease activity of SLE was examined. Twenty-seven patients (26 women and 1 man, mean age 43 years), in whom extramural coronary artery lesions were excluded by coronary angiogram or presumed to be excluded by exercise electrocardiogram, were enrolled in this study. The mean duration of disease and the mean duration of corticosteroid therapy in these patients were 94 and 77 months, respectively. Exercise thallium-201 scintigraphy was performed twice (mean interval, 30 months) to evaluate the progression of myocardial damage. Myocardial ischemia as an index of myocardial damage was evaluated by visual analysis and ischemic score (IS). The changes in myocardial ischemia were categorized into 3 groups: improved, unchanged or worsened. The disease activity of SLE was determined by the SLE Disease Activity Index (SLEDAI), and the changes in this index were classified into the same three categories, as evaluated every six months between the two scintigraphic examinations. Disease activity was significantly correlated with myocardial ischemia (p<0.05), and with myocardial ischemia as diagnosed by ?IS (difference in ischemic score between the first and second thallium-201 scintigrams: p<0.005). But neither the duration of disease nor the duration of corticosteroid therapy was correlated with IS at the first scintigraphy. These results indicate that control of SLE disease activity may be critical in the treatment of myocardial damage resulting from vascular lesions, especially intramyocardial small-artery disease, in patients with SLE. (author)

  15. Myocardial infarction in rats: High-resolution single-photon emission tomographic imaging with a pinhole collimator

    Energy Technology Data Exchange (ETDEWEB)

    Yukihiro, Masashi [Dept. of Nuclear Medicine, Gunma Univ. School of Medicine (Japan); Inoue, Tomio [Dept. of Nuclear Medicine, Gunma Univ. School of Medicine (Japan); Iwasaki, Tsutomu [Second Dept. of Internal Medicine, Gunma Univ. School of Medicine (Japan); Tomiyoshi, Katsumi [Dept. of Nuclear Medicine, Gunma Univ. School of Medicine (Japan); Erlandsson, K. [Radiation Physics Dept., Lund Univ. (Sweden); Endo, Keigo [Dept. of Nuclear Medicine, Gunma Univ. School of Medicine (Japan)

    1996-08-01

    The purpose of this study was to evaluate the accuracy of myocardial imaging by means of high-resolution single-photon emission tomography (SPET) with a pinhole collimator in rats with experimental infarction. Myocardial infarctions were induced in male Wistar rats by ligation of the left coronary artery for 30 min, followed by reperfusion. Two days after the reperfusion, pinhole SPET was performed after the intravenous administration of 111 MBq of thallium-201 chloride, using a rotating gamma camera equipped with a pinhole insert (2.0-mm aperature) in a low-energy pinhole collimator. SPET projection data were collected at 6 increments over 360 using a 4-cm radius of rotation to reconstruct the short- and long-axis images. Projection data were acquired in 15 or 30 s, the SPET imaging being accomplished within 40 min after the injection of {sup 201}Tl. After SPET, the rats were sacrificed to remove the hearts for autoradiography (ARG) and nitroblue tetrazolium (NBT) staining as a visual correlative study. Quantitative correlative studies between pinhole SPET and ARG were performed with linear regression analysis for infarct size and distribution properties (relative counts on SPET images and relative density on autoradiographs) on the short-axis sections. All infarcts (4 mm in minimum diameter) in seven rats were detected by pinhole SPET. The SPET images in rats with or without myocardial infarction were consistent within the findings of ARG and NBT staining. There were significant correlations between pinhole SPET and ARG with respect to the infarct size (r=0.933, P<0.001; n=15) and the relative radiotracer distribution (r=0.931, P<0.001; n=68). This study therefore confirmed the accuracy of myocardial pinhole SPET imaging in rats with myocardial infarction. This method may partially substitute for ARG and prove useful for assessing new myocardial imaging agents in vivo in small laboratory animals. (orig.)

  16. 201Tl heart studies

    International Nuclear Information System (INIS)

    At the annual meeting of the Society of Nuclear Medicine there was a preponderance of papers dealing with the heart. The most impressive papers detailed the use of monovalent cation 201Tl in the evaluation of coronary artery disease. Thallium-201 behaves like potassium in that it enters heart muscle quickly and persists in that organ for several hours. It is unlike most radioactive potassium analogues used for heart studies in that: (1) its gamma energy peaks (69 keV and 80 keV) are more easily collimated with resultant image improvement, (2) its physical half life of 72 hours is sufficiently short to attain high counting rates without too much radiation and is sufficiently long so that storage is not prohibitive, (3) its short half life and lack of Beta radiation results in lower radiation to the patient, and (4) its uptake in heart is greater and uptake in liver and stomach less than other potassium analogues

  17. Incremental value of 24-hour delayed imaging in 201Tl stress myocardial perfusion studies (MPS) with an 'early rest reinjection' protocol

    International Nuclear Information System (INIS)

    Full text: One hundred patients (pts) undergoing stress MPS had 24 h imaging for fixed defects at 4 h delayed imaging. 53 had prior myocardial infarction (MI) and 71 were males. Stress employed isotonic exercise with dipyridamole (0.56 mg kg-1) infusion in 57 pts, exercise alone in 33 and dipyridamole alone in 10. All pts with stress defects had rest-reinjection of 40 MBq of 201Tl after stress imaging had been completed, and most had sublingual nitrate therapy 10 min before reinjection. MPS from the 100 pts (15% of total) were read without clinical data, using a 20 segment scoring system. 51 pts showed -2 segments improvement between 4 and 24 h scores, but 22 pts had shown reversibility between stress and 4 h imaging and the further change did not alter interpretation. The other 29 pts (group A) showed clinically important change in 24 h scores, leaving 71 pts without clinical change (group B). Segmental improvement between 4 and 24 h in group A was 4.62 ± 2.18 and 1.18 ± 1.48 in group B (P = 0.02). Group A stress defect scores were not greater (10.90 ± 3.60) or more severe (3.72 ± 3.06) than in group B (8.92 ± 4.34 and 2.79 ± 3.11); 18 group A pts had MI compared with 38 group B pts. No significant correlation was found between improved 4-24 h scores and parameters of stress-LV dysfunction. There is benefit from 24 h, 201TI MPS in patients with persisting 4 h defects, despite early rest-reinjection and acute nitrate therapy

  18. Incidental Detection of Shoulder Peripheral T-Cell Lymphoma During the Redistribution Phase of 201Tl Myocardial Perfusion Scintigraphy.

    Science.gov (United States)

    Chen, Yu-Ren; Hsieh, Te-Chun; Yen, Kuo-Yang; Kao, Chia-Hung

    2015-10-01

    A 74-year-old woman underwent Tl myocardial perfusion scan for cardiac symptoms; increased radiotracer accumulation in the left shoulder was found in the redistribution images only, and the shoulder was normal in the stress images. Suspecting septic arthritis subsequent investigations were performed, and peripheral T-cell lymphoma was diagnosed. Attention should also be paid to extracardiac sites in interpreting redistribution images taken as late as 4 hours apart from stress images because some clinically pertinent ancillary findings may be found in redistribution images only. PMID:26018700

  19. Comparison of adenosine and exercise stress 201Tl myocardial perfusion imaging for diagnosing coronary heart disease in women

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic value of adenosine and exercise stress myocardial perfusion imaging (MPI) for detecting coronary heart disease (CHD) in women. Methods: One hundred and thirty-eight patients with CHD were randomly divided into two groups: adenosine stress group (n=69)and exercise stress group (n=69). All patients underwent myocardial SPECT evaluation. Coronary angiography (CAG), referred as 'gold standard' , was performed in each patient within 1 week before or after MPI. The diagnostic value of the two stress MPI was compared with ?2 test or Fisher's exact test. Results: In adenosine stress group, the sensitivity, negative predictive value and accuracy were 88.2% (45/51), 72.7% (16/22), 88.4% (61/69), respectively, which were not significantly different from those of the exercise stress group (91.7% (44/48), 66.7% (8/12), 81.2% (52/64); ?2 =0.571, 0.714, 0.249, P>0.05). However, the false positive rate of adenosine stress (11.1%, 2/18) was significantly lower than that of exercise stress (50.0%, 8/16), P=0.023. Conclusions: Adenosine and exercise stress MPI have similar value for CHD diagnosis in women, however, adenosine stress MPI may have an advantage of low false positive rate. (authors)

  20. Clinical assessment of effects of nitroglycerin ointment in patients with angina pectoris by quantitative stress 201Tl myocardial scintigraphy

    International Nuclear Information System (INIS)

    The effects of nitroglycerin ointment (NGO) on angina pectoris (AP), especially the increase in regional coronary blood flow were clinically examined using stress Tl-201 myocardial scintigraphy in 26 patients with AP. Scintigraphic findings included: (1) an improvement of perfusion defect due to an increased Tl-201 uptake in ischemic areas, (2) an improvement of defect in spite of unchanged uptake in ischemic areas, and (3) no improvement of defect. From these findings, two mechanisms of NGO action are considered in the presence or absence of the coronary artery response (spasm or an increased coronary artery tonus) which plays an important role in the occurrence of AP. That is, there seems to be an increased regional coronary blood flow resulting from the dilatation of the coronary artery, or the lowered pre- or post-cardiac load. (Namekawa, K.)

  1. Comparison of exercise-stress single photon emission computed tomography with thallium-201 reinjection and postextrasystolic potentiation to assess myocardial viability in patients with myocardial infarction

    International Nuclear Information System (INIS)

    Myocardial viability was examined in 20 patients with myocardial infarction 24±3 (mean±standard deviation) days after onset. Postextrasystolic potentiation (PESP) was measured by left ventriculography and thallium-201 (Tl) single photon emission computed tomography (SPECT) redistribution was assessed after stress loading and reinjection of Tl. The results were compared with the improvement of left ventricular segmental wall motion after coronary revascularization which was performed successfully in all patients. The uptake of Tl was impaired initially in 41 segments, classified into three groups: normal group, 13 segments with smooth reversion to normal; new fill-in group, 15 segments with a new fill-in after reinjection of Tl; no fill-in group, 13 segments with no fill-in after reinjection. When evaluated by the PESP before coronary revascularization, segmental wall motion was significantly augmented in all segments in the normal group and new fill-in group (p<0.001), but not in the no fill-in group. After coronary revascularization, left ventriculography revealed that segmental wall motion was significantly improved in normal group and new fill-in group, but not in the no fill-in group except for mild improvement in five segments. The sensitivity and specificity of PESP (90% and 93%) and Tl SPECT (80% and 100%) for improvement of segmental wall motion after the coronary revascularization were very high, with the accuracy of either method attaining 87%. This result indicates that both Tl SPECT and PESP are useful for detecting viable myocardium in patients with recent myocardial infarction. (author)

  2. Comparative study of 201Tl-scintigraphic image and endomyocardial biopsy findings in patients with dilated cardiomyopathy

    International Nuclear Information System (INIS)

    201Tl-SPECT image was compared with the findings of endomyocardial biopsy in patients with dilated cardiomyopathies (DCM), and diagnostic value of 201Tl pathy pattern image for fibrosis with DCM was evaluated. Serial 22 patients diagnosed as DCM with endomyocardial biopsy findings were selected for this study (age: 50±17 y.o., male/female=17/5). Patchy pattern of 201Tl-SPECT image was visually classified into 4 stages according to the severity of inhomogeneous defect, and pathologic findings of fibrosis was also classified into 4 according to the severity of fibrosis (0: none, 1: mild, 2: moderate, 3: severe). Ejection fraction calculated from left ventriculography and end-diastolic dimension by echocardiography were also compared with 201Tl-SPECT image. Out of 22 patients, 21 patients (95%) showed fibrosis, and 18 patients (82%) showed patchy pattern with 201Tl-SPECT. Severity of patchy pattern was not in good relation to that of fibrosis (r=0.374). 201Tl image was not related to the function nor dimension. Four autopsy studies revealed a good relation of macroscopic severity, spatial distribution of fibrosis and inhomogeneous 201Tl-defect pattern before death. Patchy pattern of 201Tl-SPECT image will show the myocardial fibrosis in patients with DCM, and is independent of the function. 201Tl-SPECT may show more clinically useful findings of spatial distribution and severity of fibrosis with focal myocardial biopsy. (author)

  3. Assessment of coronary hemodynamics and myocardial perfusion in patients with syndrome X by digital subtraction angiography and 201Tl-myocardial scintigraphy

    International Nuclear Information System (INIS)

    To evaluate coronary hemodynamics and myocardial perfusion, left coronary digital subtraction angiography (DSA) and Tl-201 myocardial scintigraphy were performed in patients with syndrome X. The coronary circulation time (CCT) was significantly prolonged after the injection of isosorbide dinitrate and contrast medium i.c. Apical T1/2 was also prolonged on ergonovine malate provocation test. We suspected that the vascular response of the coronary peripheral artery was impaired, and microvascular spasm probably existed in patients with syndrome X. The prevalence of abnormal myocardial perfusion defect on exercise Tl-201 SPECT in syndrome X was very high, and coronary hemodynamics was significantly disturbed in the group of syndrome X with abnormal Tl-201 SPECT. Tl-201 lung/heart count ratio significantly increased in syndrome X on treadmill test. Because of this, exercise induced left ventricular dysfunction was suspected. We concluded that the main pathophysiological finding of impaired coronary circulation in syndrome X was microvascular spasm. (author)

  4. Assessment of coronary hemodynamics and myocardial perfusion in patients with syndrome X by digital subtraction angiography and [sup 201]Tl-myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Kentaro; Nakase, Emiko; Serizawa, Takashi; Kubota, Shinobu; Kawai, Ichiro; Saito, Takayuki; Haiyama, Tohru (Kyoto Minami Hospital (Japan))

    1992-08-01

    To evaluate coronary hemodynamics and myocardial perfusion, left coronary digital subtraction angiography (DSA) and Tl-201 myocardial scintigraphy were performed in patients with syndrome X. The coronary circulation time (CCT) was significantly prolonged after the injection of isosorbide dinitrate and contrast medium i.c. Apical T1/2 was also prolonged on ergonovine malate provocation test. We suspected that the vascular response of the coronary peripheral artery was impaired, and microvascular spasm probably existed in patients with syndrome X. The prevalence of abnormal myocardial perfusion defect on exercise Tl-201 SPECT in syndrome X was very high, and coronary hemodynamics was significantly disturbed in the group of syndrome X with abnormal Tl-201 SPECT. Tl-201 lung/heart count ratio significantly increased in syndrome X on treadmill test. Because of this, exercise induced left ventricular dysfunction was suspected. We concluded that the main pathophysiological finding of impaired coronary circulation in syndrome X was microvascular spasm. (author).

  5. The new method of evaluation for the regional myocardial function using the regional wall thickening curve obtained by ECG-gated [sup 201]Tl planar myocardial scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Masahiko; Ozaki, Masaharu; Furutani, Yuhji; Saiki, Atsushi; Matsuzaki, Masanori (Yamaguchi Univ., Ube (Japan). School of Medicine); Takahashi, Yohjiro

    1994-01-01

    A new method was developed for obtaining an increase rate of regional myocardial systolic wall thickness (%WT) in ECG-gated Tl-201 myocardial scintigraphy. Its value was assessed in the clinical setting in comparison with %WT obtained by echocardiography. The subjects were a total of 18 patients with cardiac diseases, including angina pectoris (7), hypertension (3), dilated cardiomyopathy (4), aortic valve stenosis (2), aortic valve regurgitation (one) and sick sinus syndrome (one). Left ventricular septal and posterolateral segments were defined as regions of interest (ROI) on LAO 45deg planar images to correspond to the sites on echocardiographic left ventricular short axial M mode images. In addition, rectangular ROI, which directly crossed the ventricular wall, was assigned to determine changes in myocardial wall thickness, whereby time-activity curve (TAC) was prepared. TAC obtained so far was analogous to that obtained by ultrasound crystal method in an animal experiment. Thus the TAC was supposed to reflect changes in regional myocardial wall thickness. Furthermore, enddiastolic count (EDC) and endsystolic count (ESC) were obtained. %WT was obtained by a formula of (ESC - EDC)/EDC*100. %WT obtained in this way correlated positively with that obtained by echocardiography, for both septal segment (r=0.78) and posterolateral segment (r=0.77). These findings suggested that the regional wall thickening curve can be used in the clinical setting. (N.K.).

  6. A comparison between terminally radioiodinated hexadecenoic acid (sup(*)I-HA) and 201Tl-thallium chloride in the dog heart

    International Nuclear Information System (INIS)

    The regional myocardial distribution of 131I-16-iodo-9-hexadecenoic acid (131I-HA) and 201Tl-thallium chloride (201TlCl) was determined in normal dogs and after occlusion of a coronary artery. The uptake of 131I-HA was about 20% lower than that of 201TlCl but the ratio 201Tl/131I was the same for the whole myocardium within narrow limit for normal as well as infarcted tissue. The potential of 123I-HA as a radiopharmaceutical for diagnosis of myocardial defects is discussed. (orig.)

  7. Prognostic value of myocardial perfusion single-photon emission computed tomography for the prediction of future cardiac events in a Japanese population. A middle-term follow-up study

    International Nuclear Information System (INIS)

    The prognostic value of rest 201Tl/stress 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography (SPECT) for the prediction of future hard cardiac events, including acute myocardial infarction (AMI), unstable angina (UAP) and cardiac death, and the implications for risk stratification has not yet been defined in a Japanese population. The 1,988 patients who underwent rest 201Tl/stress 99mTc-tetrofosmin SPECT were identified and followed up for the occurrence of AMI, UAP and cardiac death. The mean follow-up interval was 26.9±15.8 months. The 142 patients were revascularized within 60 days after SPECT and they were censored from the prognostic analysis. Summed stress score (SSS), summed rest score and summed difference score (SDS) were calculated using a 5-point scoring (Normal: 0, No uptake: 4) and a 20-segment model; 22 cases of myocardial infarction, 31 of UAP and 22 cardiac deaths occurred (1.2%, 1.7% and 1.2%, respectively). Multivariate Cox regression analysis showed that hypertension (Wald 6.37, p<0.05) and SDS (Wald 8.77, p<0.01) were independent predictors of AMI and UAP. Advanced age (Wald 16.0, p<0.001), SSS (Wald 10.9, p<0.01) and SDS (Wald 4.58, p<0.05) were independent predictors of cardiac death. Myocardial perfusion SPECT yields prognostic information toward the identification of acute coronary syndrome and cardiac death. (author)

  8. The interpolated projection data estimation method improves the image quality of myocardial perfusion SPECT with a short acquisition time

    International Nuclear Information System (INIS)

    The interpolated projection data estimation processing (IPDE) method increases the amount of projection data by interpolation of the projection data. We examined the usefulness of the IPDE method for 201Tl myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) with a short acquisition time. Forty patients with suspected ischemic heart disease underwent stress 201Tl-MPI SPECT. Both stress and delayed images were acquired with 4 cycles of 360 deg continuous rotation with a 90-direction setting for 14 min. The projection data used for reconstruction were all cycle data (Tl-90-14 min), 2 cycles of data (Tl-90-7 min), and 2 cycles of data processed using the IPDE method (Tl-180IPDE-7 min). This study compared the detection of the perfusion defect by the uptake score and the image quality of 201Tl-MPI SPECT using the normalized mean square error (NMSE). The uptake score of Tl-180IPDE-7 min was significantly more concordant with Tl-90-14 min in comparison to the Tl-90-7 min (p201Tl-MPI SPECT than for the stress 201Tl-MPI SPECT (p201Tl-MPI SPECT for a short acquisition time. Furthermore, the IPDE method is a simple software program that does not require any expensive equipment or use advanced algorithms. These results suggest that the IPDE method may be useful as an adjunctive method for shortening the acquisition time of 201Tl-MPI SPECT. (author)

  9. Usefulness of 201Tl SPECT in the evaluation of treatment effect for primary lung cancer

    International Nuclear Information System (INIS)

    Thallium-201 single photon emission computed tomography (201Tl SPECT) was performed on 20 patients with primary lung cancer before and after treatment (radiotherapy alone or combination of chemotherapy and radiotherapy). They were divided into early recurrence group and no recurrence group by presence of local tumor regrowth within 6 months after treatment. Retention index (Ret. I) after treatment was significantly lower (p201Tl SPECT indicated viability of residual mass, so it was useful in the evaluation of treatment effect for primary lung cancer. (author)

  10. Diagnostic significance of positive I-123 BMIPP despite negative stress Tl-201 myocardial imaging in patients with suspected coronary artery disease

    International Nuclear Information System (INIS)

    There is frequently discordance in the interpretation of myocardial single-photon emission computed tomography images using both rest iodine-123 15-(p-iodophenyl)-3-(R, S) methylpentadecanoic acid (BMIPP) and stress thallium-201 (201Tl); that is, negative BMIPP vs positive 201Tl studies. However, little attention has been paid to reverse discordance (ie, positive BMIPP despite negative stress 201Tl). In the present study 105 consecutive patients with suspected coronary artery disease (CAD) who underwent both rest BMIPP and stress 201Tl imaging were evaluated. No patient with previous myocardial infarction was included. Scintigraphic studies revealed that BMIPP was in concordance with 201Tl in 71 patients: both were positive in 38 and negative in 33, whereas both were discordant in 20 and reverse discordant in 14. In patients with reverse discordance, the pattern of BMIPP abnormality was segmental in 8 and spotty in 6; the former was related to coronary territory. Based on the BMIPP findings and clinical symptoms, 7 patients with positive BMIPP despite negative 201Tl underwent coronary angiography: 3-vessel CAD was found in 3 patients, 2-vessel CAD in 1, coronary spasm in 2, and insignificant lesions in 1. In the remaining 7 patients, no cardiac event was observed during 2-year follow-up. In patients showing positive BMIPP despite negative 201Tl, a segmental BMIPP perfusion abnormality indicates a high likelihood for CAD, despite normal stress 201Tl imaging. Thus, adding BMIPP to 201Tl imaging may help to better identify patients with significant CAD, including multivessel disease. (author)

  11. Determination of [{sup 201}Tl]Tl(III) in [{sup 201}Tl]TlCl solutions using HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Akhlaghi, M. [Nuclear Medicine Group, Agriculture, Medicine and Industrial Research School (AMIRS), Nuclear Science and Technology Research Institute, Moazzen Blvd., Rajaeeshahr, P.O. Box 31485-498, Karaj (Iran, Islamic Republic of)], E-mail: makhlaghi@nrcam.org; Kamalidehghan, M.; Jalilian, A.R.; Shadanpoor, N. [Nuclear Medicine Group, Agriculture, Medicine and Industrial Research School (AMIRS), Nuclear Science and Technology Research Institute, Moazzen Blvd., Rajaeeshahr, P.O. Box 31485-498, Karaj (Iran, Islamic Republic of)

    2008-04-15

    A high-performance liquid chromatography technique has been presented to measure the [{sup 201}Tl]TlCl{sub 3} impurity in [{sup 201}Tl]TlCl radiopharmaceutical for precise determination of radiochemical purity. Diethylene tetraamine pentaacetic acid (DTPA) has been used for complete complexation of [{sup 201}Tl]Tl(III). [{sup 201}Tl]Tl(III)-DTPA was analyzed in the presence of [{sup 201}Tl]Tl(I) using a cation exchange HPLC column.

  12. Exercise myocardial perfusion scintigraphy is useful for evaluating myocardial ischemia even in the elderly

    International Nuclear Information System (INIS)

    Pharmacologic stress testing is recommended to elderly patients as a valuable alternative to exercise testing. We examined whether exercise testing is as useful for evaluating myocardial ischemia in the elderly as in the young. The consecutive 1,508 patients who underwent exercise 201Tl single-photon emission computed tomography (SPECT) were divided into six age groups: 6-29 years (n=56), 30-44 (n=143), 45-54 (n=311), 55-64 (n=498), 65-74 (n=402), and 75-88 (n=98). Both heart rate and rate-pressure product at peak exercise were significantly lower in patients aged 75-88 than in the other five groups. The frequency of ischemic ST depression was higher in patients aged 75-88 than in those aged 6-74, although the difference was not significant. Moreover, the frequency of 201Tl transient defect was significantly higher in patients aged 75-88 than in those aged 6-74. On the other hand, the sensitivity of ischemic ST depression for 201Tl transient defect was similar among the six groups, but the specificity was significantly lower in patients aged 75-88 than in those aged 6-74. In conclusion, exercise 201Tl SPECT is useful for evaluating myocardial ischemia even in the elderly, but exercise electrocardiography has limitations such as lower specificity in the elderly than 201Tl SPECT. (author)

  13. Quantification of the extent and severity of myocardial ischemia in single-vessel disease using stress-redistribution thallium-201 single-photon emission computerized tomography

    International Nuclear Information System (INIS)

    Single-vessel coronary artery (CA) disease (SVD) is not uniformly benign: long-term prognosis is likely to be related to the extent (E) and severity (S) of myocardial ischemia (isch). To assess the ability of stress thalium-201 (Tl) single photon emission computerized tomography (SPECT) to quantify E and S of isch, the authors studied 15 patients (pts) without myocardial infarction who had SVD (8 LAD, 4 RCA, and 3 LCX). SPECT cuts were analyzed using maximum count circumferential profiles (CPs) which were compared with previously established normal (nl) limits derived from 20 nl pts. E of isch was defined as the % of the CP points falling below nl, S and depth (D) of ischemia respectively expressed the total and the mean % by which the abnormal points fell below normal limits. Although all pts had SVD, the range of E, S and D of isch was wide (0 to 48% and 0 to 38% and 0 to 20% respectively). CA scores (CS) were derived using a 15-point system accounting for the distribution of the diseased CA, location, and degree of stenosis, and collateral supply. CS varied from 1.2 to 8. E and S significantly correlated with CS (r=.74,p=.001, and r=.78, p=.000, respectively). The 6 pts with a D ? .1 had 75% CA stenosis whereas 5 of the 9 pts with D <.1 had only 50-75% stenosis. Thus, the authors conclude that: 1) pts with SVD have highly differing degrees of isch; 2) E, S and D scores from Tl SPECT correlate favorably with the angiographic extent and severity of disease; and 3) SPECT offers potential for quantification of the magnitude of isch and may become a useful, noninvasive prognostic indicator

  14. Efficacy of iodine-123-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid single photon emission computed tomography imaging in detecting myocardial ischemia in children with Kawasaki disease

    International Nuclear Information System (INIS)

    To evaluate its efficacy in detecting myocardial ischemia in children, iodine-123-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) imaging was performed in 16 pediatric patients with Kawasaki disease (KD, 11 male, 5 female; mean age and range: 13 years 8 months and 8 years 11 months to 17 years 7 months). Five children with chest pain and no cardiac disease were studied as controls (2 male, 3 female; mean age and range: 13 years 4 months and 9 years 4 months to 17 years 11 months). Selective coronary angiography was also performed in the 16 patients to evaluate the location of coronary stenosis and coronary aneurysms. The SPECT images were expressed as polar maps (Bull's eye maps) and the 'defect' area was defined as where the uptake of BMIPP was less than the standardized BMIPP images of the 5 control children. In the 16 patients, 33 segments had coronary aneurysms and 10 (10/33: 30.3%) had significant coronary stenosis on selective coronary angiography. Nine of the 10 (90%) segments with significant coronary stenosis showed a defect on the BMIPP image whereas only 6 of the 23 (26.1%) segments without coronary stenosis showed a defect on BMIPP imaging. The sensitivity of BMIPP SPECT imaging for detection of coronary stenosis was 90% (9/10) and its specificity was 73.9% (17/23), whereas the sensitivity of 201Tl SPECT imaging was 80% (8/10) and its specificity was 60% (14/23). There was no significant difference between the BMIPP and 201Tl SPECT images in either the sensitivity or specificity for the detection of coronary stenosis. In the present series, only one case had discordant BMIPP uptake (BMIPP uptake201Tl uptake) in which there was a large coronary aneurysm and re-canalization after complete obstruction at segment 1 of the right coronary artery. This discordant BMIPP uptake reflects the possibility of ischemic but viable myocardium after re-canalization of a large aneurysm in KD. In conclusion, BMIPP SPECT imaging is useful for detecting the areas of ischemic myocardium caused by coronary artery stenosis in children with KD. (author)

  15. 201Tl scintiscanning of the myocardium following radiotherapy of the thoracic region

    International Nuclear Information System (INIS)

    40 patients were examined by 201Tl scintiscanning after radiotherapy of the thoracic region in breast cancer and metastasizing testicular tumors, resp. The results allowed to evaluate the clinical and electrocardiographic findings in 105 follow-up patients. From 40 patients with the greater part having no cardiac symptoms, 22 revealed irreversible 201Tl fixation disturbances and 10 storage deficiency under stress with repletion after rest. These findings are interpreted as myocardial fibrosis or ischemic reaction due to radiotherapy and conclusions for follow-up checks are recommended

  16. Examinations of ischemic heart diseases by sup(201)Tl perfusion under stress

    International Nuclear Information System (INIS)

    Scintigraphic examinations of the myocardial perfusion was carried out by means of sup(201)Tl perfusion. The results obtained in 23 cases are correlated with data of coronarography carried out subsequently. The sensitivity of the new non-invasive technique was found to be 77%, its specificity 90%. (L.E.)

  17. Quantitative analysis of myocardial tracer distribution in patients with ischemic heart disease. Comparison of 201Tl and 123I-15-(p-iodophenyl)-3-methylpentadecanoic acid (BMIPP)

    International Nuclear Information System (INIS)

    Quantitative assessment of myocardial tracer uptake in stress-delayed thallium and resting BMIPP imaging was performed in 24 patients with coronary artery disease. Each distribution was displayed on the bull's eye polar map and % uptake of each distribution was calculated as a mean value in 9 myocardial segments on the polar map. Redistribution index (% delayed uptake minus % stress uptake on thallium images) and discordance index (% delayed thallium uptake minus % BMIPP uptake) were also calculated. Each parameter was compared to the visual uptake score and wall motion score on contrast left ventriculography. Excellent correlations were obtained between % uptake and the uptake score in each tracer. The % thallium and BMIPP uptake also correlated with regional wall motion score. Furthermore, a significant correlation was observed between redistribution and discordance indexes in the mildly hypoperfused segments. These data indicate that the quantitative analysis of thallium and BMIPP distributions seems to be valuable to understand relationship between perfusion and regional wall motion. The discordant BMIPP uptake may represent asynergic but viable segments. However, several important factors, such as attenuation factor should be also taken into consideration for such quantitative analysis. (author)

  18. Thallium-201 myocardial single photon emission computed tomography after isoproterenol infusion in diagnosing ischemia heart disease

    International Nuclear Information System (INIS)

    Patients with obstructive atherosclerotic disease of the peripheral arteries are often unable to undergo a standard Treadmill test for evaluation of concomitant coronary artery diseases. To establish an alternative method of testing, 27 patients had intravenous infusion of isoproterenol, up to 1.0 ?g/kg, in conjugation with myocardial thallium-201 single photon emission computed tomography (SPECT). All underwent coronary angiography. Thallium-201 myocardial SPECT after isoproterenol infusion was found to have 100 % sensitivity and 100 % specificity for detecting coronary artery diseases (stenotic or occluded coronary arteries with or without myocardial infarction) and 87 % sensitivity and 100 % specificity for detecting stenotic coronary arteries with viable regional myocardium. No major complication was experienced during and after this study. It is concluded that serial thallium-201 myocardial SPECT after isoproterenol infusion is safe, reliable and useful for detecting coronary artery disease when standard exercise test is not feasible. (author)

  19. 201Tl-redistribution analysis in early and delayed myocordial scintigrams of patients with coronary heart disease (CHD)

    International Nuclear Information System (INIS)

    Scans were performed on 8 healthy subjects and 25 with coronary heart disease proven by angiography and ventriculography including 6 with previous myocardial infarction at rest, exercise, and 1 and 2 h after exercise. Data were collected by a gamma camera interfaced to a data collection system. In healthy subjects 201Tl distribution was homogeneous at rest and after exercise, the count rate ranging between 100% - as set in the region of maximum - and 80% over other regions of myocardium. In 19 patients with coronary heart disease it was uniform only at rest; 6 patients with previous myocardial infarction had locally diminished 201Tl uptake even at rest. In patients with coronary heart disease without previous myocardial infarction, scans made immediately after exercise showed significant 201Tl hypofixation in region of minimum, the count rate of which was less than 80% of the count rate as determined over region of maximum, 201Tl uptake. Scans made 1 and 2 h after exercise had filling-in of 201Tl within the region of minimum the count rate of which returned to the normal range of at least 80% of the count rate measured over region of maximum uptake. This return to resting distribution was called 201Tl redistribution. Six patients with coronary heart disease and previous myocardial infarction had 201Tl defects larger after exercise than at rest, without redistribution being observed. Redistribution in late postexercise scans is a sign of reversible ischemia in coronary heart disease. Scans at rest may be omitted in coronary heart disease, because transient ischemia is undetectable, unless spontaneous angina occurs during scan procedure. (orig.)

  20. Clinical evaluation of single-photon emission computed tomography for Tl-201 myocardial imaging

    International Nuclear Information System (INIS)

    Single-photon emission computed tomography (SPECT) for Tl-201 myocardial imaging using a rotating gamma camera was evaluated for clinical diagnostic efficacy of myocardial infarction. Thirty-three cases with prior myocardial infarction and 28 cases without myocardial infarction were injected with 2 - 4 mCi of Tl-201 at rest. Planar imaging was performed for 5 views (ANT, LAO-30, 45, 60, L-LAT) and followed by SPECT. Overall time of the studies was within one hour. Results were as follows: (1) Sensitivity, specificity and overall accuracy for myocardial infarction diagnosis of SPECT system showed 96.9%, 78.6% and 88.5% respectively. In comparison with planar imaging, SPECT significantly improved sensitivity, however decreased specificity and slightly improved accuracy. (2) Overall interpretation of transaxial, coronal and sagittal images were required for the detection of myocardial infarction. (3) SPECT images showed more clearly findings of infarction than planar imaging and extension of myocardial infarction on SPECT images showed relatively well correlation with ECG diagnosis. (author)

  1. Computer-aided diagnosis in two-phase 201Tl-SPECT of thoracic lesions

    International Nuclear Information System (INIS)

    Aim: the retention index, a traditionally quantitative analysis of two-phase 201Tl single photon emission computed tomography (SPECT) of the chest, is manually calculated by experienced physicians from comparable 2-D ROI. However, a 3-D ROI would provide more information than a 2-D ROI extracted from a single frame of SPECT. We propose a new diagnostic system, computer-aided diagnosis (CAD), to automatically detect suspicious lesions as 3-D objects on chest 201Tl-SPECT, and assist the physician in interpreting these images. Patients, methods: seventy patients with thoracic lesions and confirmed diagnoses were enrolled to test this automatic CAD system. The reliability of the CAD system in detecting lesions as 3-D objects was compared to the 2-D ROI of 201Tl-SPECT found by the manually visualized method. Furthermore, we also proposed a novel index, the retention index using the heart (RIH), to differentiate high retention (slow clearance, increasing target to heart ratio) as a criterion for a malignant lesion, from low retention (faster clearance, small or no increase of the target to heart ratio) for benign lesions. Results: the CAD system can achieve a detection rate of 100% in automatically searching for thoracic lesions in 201Tl-SPECT. In diagnostic performance, the CAD system with the RIH of comparable 3-D objects has an area under the ROC curve of 0.86, higher than the 0.78 of the traditional RI method (p = 0.198). Conclusion: the CAD system of two-phase 201Tl-SPECT is a promising tool for detecting and diagnosing thoracic lesions with a diagnostic accuracy of 0.81. (orig.)

  2. Comparison of myocardial Perfusion imaging by thallium-201 single-photon emission computed tomography with SUNY4001 (adenosine) and exercise. Crossover clinical trial at multi-center

    International Nuclear Information System (INIS)

    We compared the ischemic diagnosis ability and adverse events of 201Tl myocardial perfusion imaging with SUNY4001 (adenosine) stress to that with exercise (ergometer) stress both on random crossover trial. Thirty one known or suspected chronic stable angina patients who are able to exercise and 10 healthy volunteers were enrolled for the trial. The early and delayed images were obtained by SPECT imaging. The concordance of diagnoses [ischemia vs. no ischemia] between the two types of stresses was 97.3% (36/37) [Kappa: 0.9068]. The sensitivity and specificity based on the exercise test were 100% (6/6) and 96.8% (30/31) respectively. The incidence of adverse events caused by SUNY4001 and the exercise were 44.7% (17/38) and 52.6% (20/38), respectively. Major adverse events caused by SUNY4001 were blood pressure (BP) decrease, flushing and headache. And those by exercise were ST decrease, dyspnea and chest pain. None of the adverse events required the intervention or caused life-threatening complication in the trial. The trial showed that the ischemic diagnosis ability and safety of 201Tl scintigraphy with SUNY4001 stress are almost equal to those of the exercise stress that is considered as the standard stress method. We concluded that 201Tl imaging with SUNY4001 is safe and useful for detecting ischemic heart disease, especially for patients unable to exercise adequately. (author)

  3. Myocardial infarct quantification in the dog by single photon emission computed tomography

    International Nuclear Information System (INIS)

    Radionuclide techniques for sizing acute myocardial infarction have been hampered by the intrinsic limitations of the scintillation camera. Emission computed tomography can overcome these limitations. Single photon emission computed tomograms of the distribution of technetium-99m pyrophosphate in acute anterior and posterior infarcts were obtained in 16 dogs after death. Tomograms were also obtained in 10 dogs during life without gating. The size of the infarcts was determined by staining gross sections of the heart with nitro blue tetrazolium, dissecting out the infarcted tissue and weighing it. Infarct sizes were determined from the tomographic images and compared with the measured infarct sizes. Good images showing the location and three-dimensional extent of the infarcts were obtained in all dogs. The measured and calculated infarct sizes correlated well (r = 0.85). Comparison of the calculated sizes in the living (non-gated) and dead (physiologically gated) animals showed reasonable agreement (r = 0.87). Single photon emission computed tomography is a feasible and useful technique for localizing and sizing acute myocardial infarctions

  4. Gated single photon emission computer tomography for the detection of silent myocardial ischemia

    International Nuclear Information System (INIS)

    Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT) for the screening of silent myocardial ischemia in type 2 diabetic patients. Material and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. All subjects were also subjected to a coronary angiography, whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specificity, accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT. There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873). Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia

  5. Comparative study of 201Tl reinjection tomography and combined use of 13N-ammonia and 18F-fluorodeoxyglucose positron emission tomography for detection of viable myocardium

    International Nuclear Information System (INIS)

    Objective: To compare the clinical value of 201Tl reinjection tomography and combined use of 13N-ammonia (NH3) regional myocardial perfusion and 18F-fluorodeoxyglucose (FDG) positron emission tomography transfer function and for the myocardium. Methods: The authors performed exercise 201Tl SPECT (Tl SPECT) on 20 patients with myocardial infarction and obtained standard 201Tl exercise-redistribution images. 201Tl was reinjected immediately after redistribution study, and the images were then acquired as also. The 20 patients also underwent PET imaging with 13N-NH3 and 18F-FDG (NH3-FDG PET) within one week of the above study. Vertical and horizontal long axis cuts were divided into nine segments, and uptakes of radioisotope were evaluated into four classes visually (Defect score, DS) (0:normal uptake, 3:severely reduced). Quantitative evaluation was performed on the vertical and horizontal long axis cuts of 201Tl redistribution, reinjection and FDG PET images using regions of interest. The relative myocardial 201Tl uptake and 18F-FDG uptake (% ID) were expressed as the percentage of this reference region accounted for of the maximal counts. Results: In 48 segments identified as viable by the NH3-FDG PET images, 45 (93.8%) segments were also identified as viable by the 201Tl redistribution imaging. Of 24 segments with severe irreversible defects on the 201Tl redistribution imaging, 87.5% of the segments were concordantly confirmed by 201Tl reinjection and NH3-FDG PET images with 37.5% identified as viable and 50% identified as scar. There was no significant difference in the average % ID, furthermore, regression analysis revealed a high positive correlation in the segmental % ID between 201Tl reinjection and FDG PET images in the 61 segments with myocardial infarction (r = 0.722). Conclusions: The results show that 201Tl reinjection tomography is of similar accuracy with NH3-FDG PET for detection of viable myocardium and possess important clinical practice value

  6. Abnormal 201Tl limb scan due to unilateral tremor

    International Nuclear Information System (INIS)

    A abnormal intra- and interextremity distribution pattern on 201Tl was observed on the limb scan of a patient with a unilateral tremor. This is ascribed to the increased blood flow in the muscles responsible for the tremor. The suggestion is made that the existence of tremor should be considered as a possible explanation for unexpected abnormalities on 201Tl limb scintigrams

  7. Gated single-photon emission tomography imaging protocol to evaluate myocardial stunning after exercise

    International Nuclear Information System (INIS)

    This study was designed to apply ECG-gating to stress myocardial perfusion single-photon emission tomography (SPET) for the evaluation of myocardial stunning after exercise. Technetium-99m sestamibi was selected as the perfusion agent and a rest/exercise 1-day protocol was employed. Fourteen patients without coronary stenosis and 33 patients with coronary stenosis were enrolled in the study. We carried out three data acquisitions with ECG-gating: a 15-min data acquisition starting 30 min after the rest injection (AC1), a 5-min acquisition starting 5 min after the stress injection (AC2) and a 15-min acquisition starting 20 min after the stress injection (AC3). Calculation of left ventricular ejection fraction (LVEF) values was performed by means of automatic determination of the endocardial surface for all gating intervals in the cardiac cycle. Measured global EF values in 14 patients without coronary stenosis were 52.3%±7.6% (AC1), 60.6%±8.9% (AC2) and 55.6%±5.6% (AC3), and those in 11 patients with severe ischaemia were 53.6%±8.0% (AC1), 45.6%±12.1% (AC2) and 49.7%±10.7%. The magnitude of the depression of post-stress LVEF relative to the rest LVEF correlated with the severity of ischaemia (r=0.594, P=0.002), and segments manifesting post-stress functional depression were associated with ischaemic segments showing reversible perfusion defects. Stress myocardial perfusion SPET with ECG-gating is a feasible method for the evaluation of myocardial stunning as well as exercise-induced ischaemia. (orig.)

  8. The optimum technique for 201Tl tomography of myocardium: an investigation using phantoms

    International Nuclear Information System (INIS)

    Rotating gamma-camera tomography is used for 201Tl perfusion imaging to detect myocardial ischaemia or infarction. Variables which can affect the utility of the images include acquisition time, collimator sensitivity and resolution, spatial filtering, reconstruction matrix and display parameters. An 'Iowa' design myocardial phantom containing 201Tl, with a defect representing an unperfused area, was used to study the effect of these variables. Receiver operator characteristic (ROC) curves and contrast ratios indicated that filtering the acquisition data with a count-dependent (Metz) filter before reconstruction and using a narrow slice width gave best results. No single collimator was superior for all four defect locations investigated but low-energy general purpose and high-resolution collimators were preferred to those with greater sensitivity. Reducing acquisition time by a factor of four compared with that for routine patient imaging affected contrast ratio, uniformity and area under ROC curves insignificantly, provided the optimum reconstruction was used. Displaying tomographic sections in colour gave no improvement in ROC curves over monochrome images. Data acquisition time or administered 201Tl radioactivity might therefore be reduced below the 25 min and 80 MBq often used for patient studies. (author)

  9. Development of [201Tl](III-DTPA-human polyclonal antibody complex for inflammation detection

    Directory of Open Access Journals (Sweden)

    A.R. Jalilian

    2006-06-01

    Full Text Available Objectives: There are a couple of radiotracers used in the detection of inflammation and infection in human, but just a few of them have been widely used in routine clinical trials. 111In-labeled HIG has been extensively tested in a large number of clinical studies. Due to interesting physical properties and wide availability of thallium-201 as a SPECT radionuclide, the idea of incorporation of this nuclide into human polyclonal immunoglubin (HIgG was targeted. Methods:Thallium-201 (T1/2=3.04 d in Tl+ form was converted to Tl3+ cation in presence of O3 in 6M HCl controlled by RTLC/gel electrophoresis methods. Human polyclonal antibody (HIgG was successively labeled with 201Tl-thallium chloride after residulation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 ml of a HIgG pharmaceutical solution (5 mg/ml, in phosphate buffer, pH=8 to a glass tube pre-coated with DTPA-dianhydride (0.01 mg at 25?C with continuous mild stirring for 30 min. Preliminary in vivo studies in turpentine-oil induced inflammation in rat model was performed to determine complex distribution of the radioimmunoconjugate. Results: Total labeling and formulation of [201Tl](III-DTPA-HIgG took about 60 minutes, with a yield of 99%. A suitable specific activity product was formed via insertion of 201Tl cation. No unlabelled and/or labeled conjugates were observed upon RTLC analysis of the final preparations. The radio-labeled complex was stable in mice serum for at least 24 hours and no significant amount of free 201Tl as well as 201Tl-DTPA was observed. Trace amounts of 201Tl-thallium chloride (?1% were detected by TLC (radiochemical yield of >99%, specific activity =38 TBq/mM, radiochemical purity?98%. The preliminary SPECT at the 33.8 degree shows the absorbtion of the immunoconjugate in the dorsal inflammed lesion. The target/skin and target/blood ratio was 3 after 28h, showing the high selectivity of the radiopharmaceutical for the inflammatory lesions. The final preparation was administered to normal rats and biodistribution of the radiopharmaceutical was checked 1 and 6 hours later by scarification. Conclusion: there are lots of upportunities for radiopharmacist and interested nuclear medicine students to look at Tl-201 not only as a myocardial tracer but as a new radionulclide for kit formulations.

  10. Preparation and biodistribution of [201Tl](III vancomycin complex in normal rats

    Directory of Open Access Journals (Sweden)

    A.R. Jalilian

    2006-06-01

    Full Text Available Objectives: Thallium-201 (T1/2=3.04d has been used in clinical nuclear cardiology and oncology for 3 decades. The development of [201Tl](IIIradiopharmaceuticals could provide many advantages: the chemistry of [201Tl](IIIcomplexation molecule is simple and the complexation constant for most of Tl(III complexes are among the highest. A wide variety of radiopharmaceuticals have been proposed for the scintigraphic detection of inflammatory and infectious disease. [67Ga]Citrate, being the most primitive radiotracer for this purpose, has a high sensitivity for both acute and chronic infections and noninfectious inflammation. Based on our previous experiences on the production and biological evaluation of radiolabelled glycopeptide antibiotics and vast clinical application of vancomycin for therapeutic purposes, we were interested in preparation of radiolabelled vancomycin as a possible infection imaging agent. Methods: Thallium-201 (T1/2=3.04 d in Tl+ form was converted to Tl3+ cation in presence of O3 in 6M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with vancomycin (VAN in water to yield [201Tl](IIIVAN after mixing the reactants followed by SPE purification using Si Sep-Pak. Radiochemical purity and stability of 201Tl-VAN in the preparation and in presence of human serum was determined up to 5.5 d. Biodistribution study of 201Tl(III-vancomycin in normal rats was performed up to 52 h. Results: The best results were obtained at room temperature in water after 30min with a radiochemical yield>99%, The studies showed that thallic ion is mostly incorporated into vancomycin with a radiochemical purity of more than 98?1% by RTLC. A specific activity of about 1.2 Ci/mmol was obtained. This pattern was also observed after IV injection to the normal rats at the same time intervals. Conclusion: [201Tl](IIIvancomycin, can be SPECT radiotracer with a rather long half life, meeting radiopharmaceutical standards for use in remote nuclear medicine centers. There are lots of opportunities for radiopharmacists and interested nuclear medicine students to look at Tl-201 not only as a myocardial tracer but as a new radionulclide for kit formulations.

  11. Detection of myocardial infarction with dual energy CT myocardial iodine maps and perfusion myocardial single photon emission computed tomography scintigraphy: an experimental study in canine

    International Nuclear Information System (INIS)

    Objective: To investigate the feasibility and accuracy of dual energy CT myocardial iodine maps in detecting acute myocardial infarction in canine model. Methods: Myocardial ischemia model was made by ligaturing left anterior descending coronary arteries (LAD) after thoracotomy in six dogs, while another 3 dogs undergoing thoracotomy not ligaturing LAD as control group. Before and three hours after operation, dual-source CT (DSCT) was performed, followed by resting 99Tcm-MIBI single photon emission computed tomography myocardial perfusion imaging. Then, dogs were sacrificed, and the hearts were removed, triphenyketrazolium chloride staining and conventional HE staining were performed. CT number of non-ischemic and ischemic regions were measured and analyzed. The wall of the left ventricle in the short axis was divided into 17 segments, the segments of myocardial perfusion defect in DSCT myocardial iodine maps, SPECT, and pathology were determined. Student t test was used to analyze the difference of CT number between infarcted and non-infarcted myocardium. Kappa test was used for the accuracy of DSCT myocardial iodine maps and SPECT in detecting myocardial ischemia according to the pathological results. Results: No abnormal regions were detected using DSCT myocardial iodine maps in preoperative control and infarction group. After thoracotomy, partial sparse or defective perfusion was consistently noted in six dogs' apical anterior and partition wall in both DSCT myocardial iodine maps and SPECT. In the infarcted group, the attenuation of infarction region (34.75±16.66) HU was significantly decreased compared with preoperative measurements (123.18±15.38 ) HU (t=10.526, P<0.01); decreased perfusion in the infarcted region was also noted in the DSCT myocardial iodine maps and SPECT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT myocardial iodine maps and SPECT were 85.0% (34/40), 84.1% (95/113), 65.4% (34/52), 94.0% (95/101), and 82.5% (33/40), 90.3% (102/113), 75.0% (33/44), 93.6% (102/109), respectively. Kappa values were 0.63 and 0.71 for the agreement of DSCT myocardial iodine maps and SPECT. Conclusion: DSCT myocardial iodine maps is comparable diagnostic accuracy with rest SPECT myocardial perfusion imaging in detection of acute myocardial infarction in a canine model. (authors)

  12. Microcystic meningioma with late-phase accumulation on Thallium-201 single-photon emission computed tomography. Case report

    International Nuclear Information System (INIS)

    Microcystic meningiomas are rare but benign brain tumors. Previous reports have shown that Thallium-201 single-photon emission computed tomography (201Tl SPECT) demonstrated a higher late-phase accumulation of 201Tl in malignant or recurrent meningiomas than in nonaggressive meningiomas. No study has reported 201Tl SPECT findings in microcystic meningiomas. We here describe a case of a microcystic meningioma with a high 201Tl SPECT retention rate in a 62-year-old woman who complained of headache. Computed tomography revealed an intracranial tumor in the right frontal lobe. Moreover, 201Tl SPECT revealed a high uptake of 201Tl in the tumor, which was particularly prominent in the delayed phase. The uptake index on an early image was 1.46 and that on a delayed image was 1.35. Therefore, the retention index was 0.92. After 2 years of tumor growth, we performed successful radical resection, and histological examination revealed the presence of a microcystic meningioma. Therefore, we concluded that 201Tl SPECT may be useful for the preoperative diagnosis of microcystic meningiomas and that late-phase accumulation of 201Tl is not a specific finding of malignant brain tumors. Therefore, we need to be careful in the evaluation and judgment of high retention in a delayed image of 201Tl SPECT. (author)

  13. Value of 123I-BMIPP scintigraphy in patients with ischemic heart disease. Comparison with exercise 201Tl SPECT

    International Nuclear Information System (INIS)

    To evaluate 123I labeled beta-methyl-branched fatty acid (BMIPP) myocardial uptake at rest in the segment with and without stress induced ischemia in patients with coronary artery disease, 123I-beta-methyl-branched fatty acid myocardial scintigraphy was performed at rest and was compared with the findings of stress-reinjection 201Tl myocardial scintigraphy in 31 patients with coronary artery disease. In 159 ischemic myocardial segments, equally decreased uptake on both reinjection 201Tl and fatty acid images was observed in 64 segments, more severely decreased uptake of fatty acid in 76 segments, and more severely decreased uptake of reinjection thallium in 19 segments. On the other hand, in 53 non-reversible defects, each patterns was observed in 41, 3, and 9 segments respectively. When comparing the ischemic segments with more reduced uptake of fatty acid than reinjection thallium (Group 1) and the ischemic segments with equally or less reduced fatty acid uptake than reinjection thallium (Group 2), wall motion was more severely impaired in Group 1 than in Group 2 (severe hypo- to dyskinesis was present in 32 of 54 segments in group 1 and in 21 of 75 segments in group 2, p201Tl in the segments with stress induced ischemia and wall motion was more impaired in these segments. BMIPP myocardial imaging may provide information on metabolic alterations at rest independent of perfusion abnormalities in patients with coronary artery disease. (author)

  14. Analysis of coronary hemodynamics in exercise by 201Tl scintigraphy

    International Nuclear Information System (INIS)

    From our observation that initial distribution of 201Tl in tissue is mainly dependent on blood flow distribution, we designed the method to obtain the rates of change of coronary blood flow and coronary vascular resistance and applied it to the analysis of coronary hemodynamics in patients with ischemic heart disease during submaximal exercise. We measured the rates of change of cardiac output (? CO) and myocardial blood flow distribution (? Fract) in two occasions by the sequential two injections of Tl, and obtained the rate of change of coronary blood flow (? Flow) from ? CO and ? Fract. Using the rate of change of mean blood pressure, we calculated also the rate of change of coronary vascular resistance (? CVR). The initial components of histograms of the right ventricle by the first and second injections of Tl were fitted into gamma function curve. S1 and S2 were the areas bounded by the curve and baseline of the first and second injections, and then the cardiac output ratio was estimated by R x S1/S2, where R was the dose ratio measured by another camera system. The five min count rates on the myocardium by the first (H1) and second (H2) injections of Tl were calculated five min after the injection. H2 was approximately H1 x R in the same condition of Tl injection but H2 was not equal to H1 x R, when the Tl injection was done in the different loading condition. Therefore the rate of change of myocardial blood flow distribution was calculated as ? Fract = (H1 x R - H2)/H2. With submaximal exercise the increases in ? CO, ? Fract and ? Flow were smaller in patients with ischemic heart disease (IHD) than those in control subjects. In the patients with IHD, there was response of lesser degree in ? Flow under increased myocardial oxygen demand, suggesting low coronary reserve in this condition. (author)

  15. Sympathetic reinnervation following heart transplantation: a double-tracer study with 123I-MIBG and 201Tl

    International Nuclear Information System (INIS)

    Sympathetic reinnervation was evaluated in 15 patients 2-69 months after heart transplantation using a double-tracer technique with 123I-MIBG and 201Tl. Since MIBG is accumulated in the same manner as norepinephrine it may serve as a tracer of the integrity and function of the sympathetic nervous system. 201Tl was used for landmarking. Planar anterior imaging was performed 15 min and 4 h after i.v. injection of 220 MBq 123I-MIBG and 37 MBq 201Tl. Image quantitation was based on the ratio of myocardial to mediastinal MIBG-uptake. Cardiac regions of interest were defined according to the 201Tl uptake. There was no evidence of sympathetic reinnervation in 8 patients 2-34 months after transplantation. Increased MIBG-uptake could be observed in the anterior basal region in 6 long-term cardiac transplants (37-69 months). One patient with a 59-month-old transplanted heart did not reinnervate. Increased MIBG-uptake in the anterior basal region indicating partial sympathetic reinnervation could be shown in 40% of the investigated patients with an average organ age of 51 months. (orig.)

  16. Technetium-99m tetrofosmin myocardial perfusion single photon emission computed tomography in syndrome X. A preliminary report

    International Nuclear Information System (INIS)

    Syndrome X is used to describe patients with chest pain and a normal coronary angiogram. We reviewed technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion single photon emission computed tomography (SPECT) results and clinical data of 43 syndrome X patients and 30 healthy controls with normal left ventricular ejection fraction and no cardiac abnormalities. The Tc-99m TF myocardial perfusion SPECT results showed 12 (27.9%) syndrome X patients had normal myocardial perfusion and 31 (72.1%) had abnormal myocardial perfusion, including 6 (14.0%) patients with fixed defects, 20 (46.5%) patients with transient defects, and 5 (11.6%) patients with reverse defects. The results of exercise electrocardiogram (ECG) were not related to perfusion defects in Tc-99m TF myocardial perfusion SPECT. In contrast, all of the 30 (100.0%) healthy controls had normal myocardial perfusion SPECT results. We conclude that abnormal Tc-99m TF myocardial perfusion SPECT is common in syndrome X and does not correlate well with the exercise ECG. However, further studies with larger case numbers and long term follow up in patients with myocardial events are necessary to support our findings. (author)

  17. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Almquist, H

    2000-01-01

    The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correctionwere artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 {+-} 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer {sup 133}Xe. Because of the low energy of {sup 133}Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study.

  18. Attenuation correction in pulmonary and myocardial single photon emission computed tomography

    International Nuclear Information System (INIS)

    The objective was to develop and validate methods for single photon emission computed tomography, SPECT, allowing quantitative physiologic and diagnostic studies of lung and heart. A method for correction of variable attenuation in SPECT, based on transmission measurements before administration of an isotope to the subject, was developed and evaluated. A protocol based upon geometrically well defined phantoms was developed. In a mosaic pattern phantom count rates were corrected from 39-43% to 101-110% of reference. In healthy subjects non-gravitational pulmonary perfusion gradients observed without attenuation correction were artefacts caused by attenuation. Pulmonary density in centre of right lung, obtained from the transmission measurement, was 0.28 ± 0.03 g/ml in normal subjects. Mean density was lower in large lungs compared to smaller ones. We also showed that regional ventilation/perfusion ratios could be measured with SPECT, using the readily available tracer 133Xe. Because of the low energy of 133Xe this relies heavily upon attenuation correction. A commercially available system for attenuation correction with simultaneous emission and transmission, considered to improve myocardial SPECT, performed erroneously. This could lead to clinical misjudgement. We considered that manufacturer-independent pre-clinical tests are required. In a test of two other commercial systems, based on different principles, an adapted variant of our initial protocol was proven useful. Only one of the systems provided correct emission count rates independently on phantom configuration. Errors in the other system were related to inadequate compensation of the influence of emission activity on the transmission study

  19. Evaluating image denoising methods in myocardial perfusion single photon emission computed tomography (SPECT) imaging

    International Nuclear Information System (INIS)

    The statistical nature of single photon emission computed tomography (SPECT) imaging, due to the Poisson noise effect, results in the degradation of image quality, especially in the case of lesions of low signal-to-noise ratio (SNR). A variety of well-established single-scale denoising methods applied on projection raw images have been incorporated in SPECT imaging applications, while multi-scale denoising methods with promising performance have been proposed. In this paper, a comparative evaluation study is performed between a multi-scale platelet denoising method and the well-established Butterworth filter applied as a pre- and post-processing step on images reconstructed without and/or with attenuation correction. Quantitative evaluation was carried out employing (i) a cardiac phantom containing two different size cold defects, utilized in two experiments conducted to simulate conditions without and with photon attenuation from myocardial surrounding tissue and (ii) a pilot-verified clinical dataset of 15 patients with ischemic defects. Image noise, defect contrast, SNR and defect contrast-to-noise ratio (CNR) metrics were computed for both phantom and patient defects. In addition, an observer preference study was carried out for the clinical dataset, based on rankings from two nuclear medicine clinicians. Without photon attenuation conditions, denoising by platelet and Butterworth post-processing methods outperformed Butterworth pre-processing for large size defects, while for small size defects, as well as with photon attenuation conditions, all methods have demonstrated similar denoising performance. Under both attenuation conditions, the platelet method showed improved performance with respect to defect contrast, SNR and defect CNR in the case of images reconstructed without attenuation correction, however not statistically significant (p > 0.05). Quantitative as well as preference results obtained from clinical data showed similar performance of the denoising methods studied. In conclusion, the multi-scale platelet denoising method applied on raw projection images provides more efficient noise reduction while preserving image quality in a myocardial phantom SPECT imaging as compared to the Butterworth filter applied either on projection or reconstructed images. However, this trend in favour of the platelet denoising method was not observed on clinical data reconstructed either without or with attenuation correction

  20. Evaluating image denoising methods in myocardial perfusion single photon emission computed tomography (SPECT) imaging

    Science.gov (United States)

    Skiadopoulos, S.; Karatrantou, A.; Korfiatis, P.; Costaridou, L.; Vassilakos, P.; Apostolopoulos, D.; Panayiotakis, G.

    2009-10-01

    The statistical nature of single photon emission computed tomography (SPECT) imaging, due to the Poisson noise effect, results in the degradation of image quality, especially in the case of lesions of low signal-to-noise ratio (SNR). A variety of well-established single-scale denoising methods applied on projection raw images have been incorporated in SPECT imaging applications, while multi-scale denoising methods with promising performance have been proposed. In this paper, a comparative evaluation study is performed between a multi-scale platelet denoising method and the well-established Butterworth filter applied as a pre- and post-processing step on images reconstructed without and/or with attenuation correction. Quantitative evaluation was carried out employing (i) a cardiac phantom containing two different size cold defects, utilized in two experiments conducted to simulate conditions without and with photon attenuation from myocardial surrounding tissue and (ii) a pilot-verified clinical dataset of 15 patients with ischemic defects. Image noise, defect contrast, SNR and defect contrast-to-noise ratio (CNR) metrics were computed for both phantom and patient defects. In addition, an observer preference study was carried out for the clinical dataset, based on rankings from two nuclear medicine clinicians. Without photon attenuation conditions, denoising by platelet and Butterworth post-processing methods outperformed Butterworth pre-processing for large size defects, while for small size defects, as well as with photon attenuation conditions, all methods have demonstrated similar denoising performance. Under both attenuation conditions, the platelet method showed improved performance with respect to defect contrast, SNR and defect CNR in the case of images reconstructed without attenuation correction, however not statistically significant (p > 0.05). Quantitative as well as preference results obtained from clinical data showed similar performance of the denoising methods studied. In conclusion, the multi-scale platelet denoising method applied on raw projection images provides more efficient noise reduction while preserving image quality in a myocardial phantom SPECT imaging as compared to the Butterworth filter applied either on projection or reconstructed images. However, this trend in favour of the platelet denoising method was not observed on clinical data reconstructed either without or with attenuation correction.

  1. Preparation of 201Tl for medical use from 203Tl enriched target

    International Nuclear Information System (INIS)

    Cyclotron production of 201Tl from 203Tl enriched targets has made possible the preparation of 201Tl for medical use. The optimal proton activation conditions, a new radiochemical separation and analytical controls of 201Tl are described in detail. (author)

  2. Safety of and tolerance to adenosine infusion for myocardial perfusion single-photon emission computed tomography in a Japanese population

    International Nuclear Information System (INIS)

    Adenosine has been available for use in myocardial perfusion single-photon emission computed tomography (SPECT) in Japan since 2005. The purpose of this study was to evaluate the safety of and tolerance to thallium-201 myocardial perfusion SPECT with intravenous adenosine infusion in Japanese patients with suspected coronary artery disease. Two hundred and six consecutive patients who underwent an adenosine infusion (120 ?g·kg-1·min-1) SPECT at Sumitomo Besshi Hospital (Niihama, Japan) were investigated. The effects of adenosine infusion were monitored for each patient. A coronary angiography was performed in 81 patients. Adenosine infusion significantly decreased blood pressure and increased heart rate. Adverse reactions were observed in 161 patients (78.2%). Most reactions were transient, disappearing soon after the termination of adenosine infusion. No serious adverse reactions, such as acute myocardial infarction or death, occurred. Adenosine infusion was terminated in 3 patients (1.5%) because of near syncope or sustained 2:1 atrioventricular block. Electrocardiographic changes occurred in 15 patients (7.3%). Self-assessed scoring after SPECT showed that the patients were very tolerant (74.6% of 177 patients) of adenosine infusion myocardial SPECT. The sensitivity and specificity were 75.0% and 69.7%, respectively. Adenosine infusion myocardial SPECT is safe and well tolerated in the Japanese population, despite the frequent occurrence of minor adverse reactions. (author)

  3. Comparison of 11C-methionine PET and 201Tl SPECT in the detection of lymph node metastases from lung cancer

    International Nuclear Information System (INIS)

    A comparative study of positron emission tomography (PET) using 11C-methionine and single photon emission tomography (SPECT) of thallium chloride-201Tl was performed to detect hilar and mediastinal lymph node metastasis from non-small cell lung cancer. 11C-methionine PET and 201Tl SPECT were used in 22 patients with primary lung cancer before surgery. The findings of two modalities were compared with the pathologic findings. PET was judged, using tumor/muscle radioactivity ratio (TMR), by semiquantitative analysis. SPECT was judged visually. The sensitivity of 11C-methionine PET in detecting lymph node metastasis was 79.2%, specificity 91.5% and accuracy 87.3%. Comparative figures for 201Tl SPECT were 62.5%, 89.3% and 79.5% respectively. PET actually detected four of five metastatic lymph nodes, the size of which ranged from 7 mm to 9 mm in the short axis and were judged as negative by CT. This indicates that PET can detect even small metastatic lymph nodes. PET distinguishes adjacent metastatic nodes as separate nodes because of its high resolution, and enables us to evaluate each lymph node by semiquantitative analysis. The sensitivity of 11C-methionine PET was superior to that of 201Tl SPECT. (author)

  4. Use of ECG-gated single-photon emission tomography to assess the evolution of perfusion after acute myocardial infarction

    International Nuclear Information System (INIS)

    Serial improvement in myocardial perfusion images from the acute or subacute to the chronic stage of acute myocardial infarction (AMI) has been attributed to improved coronary microcirculation or cell function after acute ischaemia and reperfusion. However, conventionally used non-gated imaging cannot eliminate the effect of improved regional contraction. We studied the possibility that such scintigraphic improvement reflects the functional recovery by using ECG-gated myocardial perfusion imaging with technetium-99m sestamibi. Nineteen AMI patients who received acute reperfusion therapy underwent ECG-gated myocardial single-photon emission tomography (SPET) in the subacute and chronic stages. Serial changes in regional image count distributions were analysed on the non-gated, end-diastolic (ED) and end-systolic (ES) images by using segmental mean percent peak activity (MPA) and ?MPA (MPA in chronic stage - MPA in subacute stage) on bull's-eye polar maps. These changes were compared with those in regional wall motion on biplane left ventriculography (LVG) from the acute (just after reperfusion) to the chronic stage. During the follow-up, regional wall motion remained the same in 42 (group A) but improved in 17 (group B) of the 59 ischaemically compromised segments. MPA showed no improvement in group A but significant improvement in group B on the non-gated and ES images (P<0.0001 and P<0.001, respectively). However, MPA on the ED images showed no improvement in either group. In the follow-up study of AMI, the scintigraphic improvement documented on the non-gated myocardial images appears to be mainly related to the recovery of wall thickening and not to a real improvement in myocardial perfusion. Therefore, ECG-gated myocardial imaging, which enables simultaneous assessment of changes in perfusion and contraction, is preferable to conventional non-gated imaging for follow-up of AMI. (orig.)

  5. Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice

    Directory of Open Access Journals (Sweden)

    Sundaram P

    2009-01-01

    Full Text Available Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event-free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPIradiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases.

  6. Role of myocardial perfusion single photon emission computed tomography in pediatric cardiology practice

    International Nuclear Information System (INIS)

    Diagnostic and prognostic power of myocardial perfusion imaging in patients with coronary artery disease has been demonstrated with planar imaging which was further improvised with addition of gated SPECT and newer Technetium labeled myocardial perfusion tracers like SestaMIBI, Tetrofosmin. Myocardial perfusion abnormalities at rest and after stress are considered to be the best predictors of cardiac event–free survival in adults with ischemic heart disease. This article highlights various myocardial perfusion imaging (MPI) radiopharmaceuticals, exercise procedures, pharmacological stress protocols, indications for MPI and myocardial perfusion patterns in children with some of the common congenital and acquired heart diseases

  7. Utility of 123I-?-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial scintigraphy in the diagnosis of the cardiac involvement in sarcoidosis

    International Nuclear Information System (INIS)

    We evaluated the utility of myocardial scintigraphy using 123I-?-methyl iodophenyl pentadecanoic acid (123I-BMIPP) in the diagnosis of cardiac sarcoidosis. Myocardial single photon emission computed tomographies (SPECT) with 123I-BMIPP and 201Tl were performed in 26 patients with sarcoidosis. Each of basal and mid left ventricular levels of the short axis image of SPECT was divided into 6 segments, and the apical lesion obtained from the long axis image of SPECT was added making 13 segments in all. Then we got the defect score including four steps from normal uptake to defect. We examined the correlation between the defect score of 123I-BMIPP and that of 201Tl. Significant correlations were observed between defect score of 123I-BMIPP and 201Tl. The reduction of uptake in myocardial SPECT with 123I-BMIPP reflects cardiac involvement in the patients with sarcoidosis. The results suggest the usefulness of the myocardial scintigraphy with 123I-BMIPP in the diagnosis of cardiac involvement in sarcoidosis. (author)

  8. Effect of scatter correction on quantification of myocardial SPECT and application to dual-energy acquisition using triple-energy window method

    International Nuclear Information System (INIS)

    Triple-energy window (TEW) method is a simple and practical approach for correcting Compton scatter in single-photon emission tracer studies. The fraction of scatter correction, with a point source or 30 ml-syringe placed under the camera, was measured by the TEW method. The scatter fraction was 55% for 201Tl, 29% for 99mTc and 57% for 123I. Composite energy spectra were generated and separated by the TEW method. Combination of 99mTc and 201Tl was well separated, and 201Tl and 123I were separated within an error of 10%; whereas asymmetric photopeak energy window was necessary for separating 123I and 99mTc. By applying this method to myocardial SPECT study, the effect of scatter elimination was investigated in each myocardial wall by polar map and profile curve analysis. The effect of scatter was higher in the septum and the inferior wall. The count ratio relative to the anterior wall including scatter was 9% higher in 123I, 7-8% higher in 99mTc and 6% higher in 201Tl. Apparent count loss after scatter correction was 30% for 123I, 13% for 99mTc and 38% for 201Tl. Image contrast, as defined myocardium-to-left ventricular cavity count ratio, improved by scatter correction. Since the influence of Compton scatter was significant in cardiac planar and SPECT studies; the degree of scatter fraction should be kept in mind both in quantification and visual interpretation. (author)

  9. Myocardial uptake of thallium-201 diethyldithiocarbamate (Tl-201-DDC) in cultured heart cells and in humans

    International Nuclear Information System (INIS)

    We assessed the feasibility of SPECT imaging with 201Tl-diethyldithiocarbamate (201Tl-DDC), a new cerebral blood flow tracer with little redistribution, expecting to observe less extensive redistribution than with 201Tl-chloride. Myocardial sections were obtained in three patients presenting with documented coronary artery disease and injected at peak exercise with 100 MBq 201Tl-DDC. In two patients there was a clear redistribution phenomenon at four h after injection. In cultured myocardial cells of newborn rats, the uptake and washout of 201Tl-chloride and 201Tl-DDC were compared. The 201Tl-DDC uptake was lower than 201Tl-chloride (transmembrane gradients were respectively 89±10 and 4.1±0.2, mean±sem, n=14, P201Tl-chloride in the cells was 4% vs 19% for 201Tl-DDC. It is concluded that although myocardial imaging is feasible with 201Tl-DDC, this agent redistributes significantly with time. (orig.)

  10. Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus

    International Nuclear Information System (INIS)

    In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with 99mTc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images (''reverse redistribution pattern''). Coronary angiography was performed in eight patients with positive 99mTc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that 99mTc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole 99mTc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.)

  11. Technetium-99m sestamibi single-photon emission tomography detects subclinical myocardial perfusion abnormalities in patients with systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Schillaci, O. [Nuclear Medicine, University of l`Aquila (Italy); Lagana, B.; Gentile, R.; Tubani, L.; Baratta, L. [Department of Clinical Medicine, University ``La Sapienza``, Rome (Italy); Danieli, R.; Scopinaro, F. [Section of Nuclear Medicine, Department of Experimental Medicine and Pathology, University ``La Sapienza``, Rome (Italy)

    1999-07-01

    In patients with systemic lupus erythematosus, involvement of the cardiovascular system is the third leading cause of death. However, although autopsy studies have demonstrated a high incidence of abnormalities in both the myocardium and coronary vessels, clinical manifestations have been reported in only a small percentage of cases. The aim of this study was to evaluate myocardial perfusion in asymptomatic lupus patients using technetium-99m sestamibi single-photon emission tomography (SPET). Twenty-eight patients without overt cardiac involvement and risk factors were studied with {sup 99m}Tc-sestamibi SPET at rest and after dipyridamole infusion. Perfusion abnormalities were detected in 18 cases: six had persistent defects, three had reversible defects, seven had both persistent and reversible defects, and two showed rest defects which normalized on dipyridamole images (``reverse redistribution pattern``). Coronary angiography was performed in eight patients with positive {sup 99m}Tc-sestamibi SPET, and showed normal epicardial vessels in all the cases. These results indicate that {sup 99m}Tc-sestamibi SPET reveals a high prevalence (18 out of 28 patients in this study, i.e. 64%) of myocardial perfusion abnormalities in asymptomatic lupus patients, probably due to the primary immunological damage of this autoimmune disease. In conclusion, rest/dipyridamole {sup 99m}Tc-sestamibi SPET can be a useful non-invasive method to identify subclinical myocardial involvement in systemic lupus erythematosus, and patients potentially at risk of later cardiac events. (orig.) With 2 figs., 2 tabs., 21 refs.

  12. Physiological basis for stress-induced myocardial stunning as assessed by gated single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Postischemic myocardial stunning as assessed by gated single-photon emission computed tomography (SPECT) has been criticized for being a perfusion-associated artifact caused by false endocardial tracking. We hypothesized that if severe perfusion defects all cause false wall motion abnormality, they should be observed regardless of the underlying mechanisms of perfusion abnormality. We evaluated 132 patients with stress-induced perfusion defects of moderate severity or more after exercise (n=84) or adenosine triphosphate disodium (ATP) stress (n=48) were evaluated using gated 99mTc-sestamibi SPECT. Summed stress and difference scores were similar in the 2 groups. However, the overall incidence of post-stress stunning was 54% in the exercise group, but only 19% in the ATP group (p<0.0001). Furthermore, based on the severity of coronary artery stenosis in 43 patients with 1-vessel disease, the prevalence of post-stress stunning was 77% in patients with ?99% coronary stenosis, 67% in those with 90% stenosis, and 29% in those with 75% stenosis after exercise stress, whereas it was 57% in those with ?99% stenosis, 17% in those with 90% stenosis, and 0% in those with 75% stenosis after ATP stress (p=0.003). The predominant mechanism of post-stress wall motion abnormality observed by gated SPECT was thought to be severe myocardial ischemia, but not a perfusion-associated artifact. Thus, this scintigraphic finding was regarded as actual myocardial stunning. (author)

  13. Utility of QGS for 201Tl electrocardiogram-gated SPECT in cardiac function evaluations

    International Nuclear Information System (INIS)

    QGS (quantitative gated SPECT) was applied to 201Tl SPECT, whose images are inferior to those of Tc SPECT, and its utility was evaluated. More specifically, the cardiac function index was calculated by QGS, and local wall motion was evaluated visually. Accuracy was assessed by comparison with left ventriculography. The subjects were 29 patients (21 males, 8 females; 6 with myocardial infarction, 18 with stenocardia, 2 with pericardial disease, 3 with other heart diseases) who had undergone myocardial scintigraphy and left ventriculography between February and May, 2000. 201Tl (74 or 111 MBq) was administered to all patients. The resting image was obtained 10 minutes later, and the delayed image during loading was obtained 4 hours later. The conditions for acquiring the images were as follows. Two detectors were arranged at a 90-degree angle in the form of an L. The 180 degrees from 45 degrees right anterior oblique (RAO) to 45 degrees left posterior oblique (LPO) were divided into 30 sections at 6-degree intervals, and the image in each section was acquired for 60 seconds. The matrix was 64 x 64. As a cardiac function index, the left ventricular ejection function (LVEF) obtained by electrocardiogram-gated SPECT (QGS-EF) at the rest (14 cases) and the QGS-EF on the delayed images (15 cases) were compared with the LVEF determined by left ventriculography (LVG-EF). There was an excellent positive correlation between the data obtained by two methods, with a correlation coefficient of r=0.93 (y=1.04x-0.04). Most of the difference between the values fell within two standard deviations, and the error was in the clinically allowable range. There was no significant difference between the correlation coefficient at rest and during loading or between the cases that showed an obvious defect on the image and those that did not. The local wall motion of the left ventricle was visually evaluated in five stages in two directions (RAO, 30 degrees, and LAO, 60 degrees). The motion scores in the QGS image and the LVG image agreed in 124 (67.4%) of 184 areas. A difference of one level in the score was shown in 42 areas (22.8%) and a difference of 2 or more levels in the score in 18 areas (9.8%). The results demonstrated that evaluation of myocardial blood-flow functions by 201Tl electrocardiogram gated SPECT is possible. (K.H.)

  14. Utility of QGS for {sup 201}Tl electrocardiogram-gated SPECT in cardiac function evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Shimazaki, Hiroshi; Oono, Ryuichi [Sapporo Kosei Hospital (Japan)

    2001-07-01

    QGS (quantitative gated SPECT) was applied to {sup 201}Tl SPECT, whose images are inferior to those of Tc SPECT, and its utility was evaluated. More specifically, the cardiac function index was calculated by QGS, and local wall motion was evaluated visually. Accuracy was assessed by comparison with left ventriculography. The subjects were 29 patients (21 males, 8 females; 6 with myocardial infarction, 18 with stenocardia, 2 with pericardial disease, 3 with other heart diseases) who had undergone myocardial scintigraphy and left ventriculography between February and May, 2000. {sup 201}Tl (74 or 111 MBq) was administered to all patients. The resting image was obtained 10 minutes later, and the delayed image during loading was obtained 4 hours later. The conditions for acquiring the images were as follows. Two detectors were arranged at a 90-degree angle in the form of an L. The 180 degrees from 45 degrees right anterior oblique (RAO) to 45 degrees left posterior oblique (LPO) were divided into 30 sections at 6-degree intervals, and the image in each section was acquired for 60 seconds. The matrix was 64 x 64. As a cardiac function index, the left ventricular ejection function (LVEF) obtained by electrocardiogram-gated SPECT (QGS-EF) at the rest (14 cases) and the QGS-EF on the delayed images (15 cases) were compared with the LVEF determined by left ventriculography (LVG-EF). There was an excellent positive correlation between the data obtained by two methods, with a correlation coefficient of r=0.93 (y=1.04x-0.04). Most of the difference between the values fell within two standard deviations, and the error was in the clinically allowable range. There was no significant difference between the correlation coefficient at rest and during loading or between the cases that showed an obvious defect on the image and those that did not. The local wall motion of the left ventricle was visually evaluated in five stages in two directions (RAO, 30 degrees, and LAO, 60 degrees). The motion scores in the QGS image and the LVG image agreed in 124 (67.4%) of 184 areas. A difference of one level in the score was shown in 42 areas (22.8%) and a difference of 2 or more levels in the score in 18 areas (9.8%). The results demonstrated that evaluation of myocardial blood-flow functions by {sup 201}Tl electrocardiogram gated SPECT is possible. (K.H.)

  15. Computerized study with 201Tl of the gold thyroid node

    International Nuclear Information System (INIS)

    Because of its physical and potassium-metabolic characteristics 201Tl is more suitable than 131Cs for radioisotopic studies of the cold thyroid nodule, with the further diagnostic possibility of quantitatively assessing intranodular behaviour for a specific differentiation among different kinds of neoformations. Using a gamma-camera on line with a computer data processing device, sequential scintiscans were recorded for the first 20-30 min after i.v. administration of 15-20 ?Ci/kg of radiothallium; delayed sequences were taken at 40-60 min if intranodular uptake appeared. A quantitative appraisal was made of the differential 201Tl uptake-ratio between nodule and healthy thyroid tissue (density-index) and the multiparameter analysis of thyroid time/activity curves generated on the relative regions of interest (ROIs). This computerized study, in 120 out of 293 patients submitted to this radiothallium test, has shown a) diagnostic agreement between clinical-histological and radioisotopic findings in 76 out of 79 colloid-cystic or degenerative neoformations, in all 16 malignant and in 23 out of 25 hyperplastic benign nodules; b) significant statistical difference of the density-index in solid versus cystic but not between benign and malignant nodules; c) different 201Tl kinetics behaviour in different kinds of solid thyroid lesions with a satisfactory statistical difference of the radiothallium nodular dissappearance-index. (orig.)

  16. A new dynamic myocardial phantom for the assessment of left ventricular function by gated single-photon emission tomography

    International Nuclear Information System (INIS)

    Gated myocardial perfusion single-photon emission tomography (SPET) has been used for the measurement of left ventricular (LV) function and validated by means of comparison with other imaging modalities. We have designed a new dynamic myocardial phantom in order to validate the LV function as assessed by the use of gated myocardial perfusion SPET. The phantom consists of two half-ellipsoids (an endocardial surface and an epicardial surface) and a thorax. The myocardial space is filled with a radioactive solution. The endocardial surface moves continuously towards and away from the epicardial surface in the longitudinal axis to vary the LV volume [143 ml at end-diastole (ED), 107 ml at end-systole (ES)] and thickness (apex 8 mm at ED and 26 mm at ES, midplane 8 mm). The mean values of wall motion (WM) for the apical midplane region and the basal midplane region were 5 mm and 2 mm, respectively. Gated myocardial SPET was performed during 8 and 16 intervals. These projection data sets were processed using a Butterworth filter with an order of 5 and a critical frequency of 0.34 cycles/cm. LV function was calculated using the quantitative gated SPET (QGS) algorithm. The LV function values estimated by gated SPET during 16 intervals [22% for ejection fraction (EF), 3.7 mm for WM of the apical midplane, 1.7 mm for WM of the basal midplane] closely resembled actual LV functions [25% for EF, 5 mm for WM of the apical midplane, 2 mm for WM of the basal midplane]. However, the estimated values during 8 intervals were smaller than those during 16 intervals (19% for EF, 3.3 mm for WM of the apical-midplane, 1.1 mm for WM of the basal-midplane). The estimated LV volumes closely correlated with the actual volumes (r=0.99 for 16 intervals, r=0.95 for 8 intervals). Utilizing this phantom, LV function estimated using gated myocardial SPET can be compared with actual values. (orig.)

  17. A new dynamic myocardial phantom for the assessment of left ventricular function by gated single-photon emission tomography.

    Science.gov (United States)

    Kubo, N; Morita, K; Katoh, C; Shiga, T; Konno, M; Tsukamoto, E; Morita, Y; Tamaki, N

    2000-10-01

    Gated myocardial perfusion single-photon emission tomography (SPET) has been used for the measurement of left ventricular (LV) function and validated by means of comparison with other imaging modalities. We have designed a new dynamic myocardial phantom in order to validate the LV function as assessed by the use of gated myocardial perfusion SPET. The phantom consists of two half-ellipsoids (an endocardial surface and an epicardial surface) and a thorax. The myocardial space is filled with a radioactive solution. The endocardial surface moves continuously towards and away from the epicardial surface in the longitudinal axis to vary the LV volume [143 ml at end-diastole (ED), 107 ml at end-systole (ES)] and thickness (apex 8 mm at ED and 26 mm at ES, midplane 8 mm). The mean values of wall motion (WM) for the apical midplane region and the basal midplane region were 5 mm and 2 mm, respectively. Gated myocardial SPET was performed during 8 and 16 intervals. These projection data sets were processed using a Butterworth filter with an order of 5 and a critical frequency of 0.34 cycles/cm. LV function was calculated using the quantitative gated SPET (QGS) algorithm. The LV function values estimated by gated SPET during 16 intervals [22% for ejection fraction (EF), 3.7 mm for WM of the apical midplane, 1.7 mm for WM of the basal midplane] closely resembled actual LV functions [25% for EF, 5 mm for WM of the apical midplane, 2 mm for WM of the basal midplane]. However, the estimated values during 8 intervals were smaller than those during 16 intervals (19% for EF, 3.3 mm for WM of the apical-midplane, 1.1 mm for WM of the basal-midplane). The estimated LV volumes closely correlated with the actual volumes (r=0.99 for 16 intervals, r=0.95 for 8 intervals). Utilizing this phantom, LV function estimated using gated myocardial SPET can be compared with actual values. PMID:11083542

  18. Impact of Co-morbidity on the Risk of First-Time Myocardial Infarction, Stroke, or Death After Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging

    DEFF Research Database (Denmark)

    Schelde, Astrid Blicher; Schmidt, Morten

    2014-01-01

    The impact of co-morbidity on the cardiovascular risk after single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) remains unclear. We examined the association between a normal versus abnormal SPECT MPI scan on 10-year risk of myocardial infarction, stroke, and all-cause death, overall and according to co-morbidity level. We identified all patients without previous myocardial infarction or cerebrovascular disease, who had an SPECT MPI performed at Aarhus University Hospital Skejby during 1999 to 2011. We categorized the SPECT MPI scan as normal (no defects) or abnormal (reversible and/or fixed defects). Using nationwide medical registries, we obtained information on co-morbidity level (using Charlson co-morbidity index) and outcomes. We used Cox regression to compute hazard ratios with 95% confidence intervals (CIs), adjusting for gender, age, and co-morbidity level. Among 7,040 patients, 4,962 (70%) had normal scans and 2,078 (30%) abnormal scans. Patients with a normal versus abnormal scan had a 10-year risk of 5.7% versus 10.9% for myocardial infarction, 6.0% versus 7.8% for stroke, and 16.5% versus 29.0% for all-cause death. After adjustment, an abnormal scan was associated with increased risk of myocardial infarction (adjusted hazard ratio 1.73, 95% CI 1.37 to 2.18) and all-cause death (1.42, 95% CI 1.23 to 1.65) but not stroke (1.12, 95% CI 0.86 to 1.45). Co-morbidity level did not affect substantially the association between the scan result and the outcomes. In conclusion, independently of co-morbidity level, an abnormal SPECT MPI scan was associated with an increased 10-year risk of myocardial infarction and all-cause death but not stroke.

  19. Single photon emission computed tomography of technetium-99m tetrofosmin myocardial perfusion imaging in patients with systemic lupus erythematosus-A preliminary report

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the utility of single-photon emission computed tomography (SPECT) of technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion imaging to detect myocardial involvement in patients with systemic lupus erythematosus (SLE). Three groups of subjects-group 1: 25 SLE female patients with non-specific cardiac symptoms and signs, group 2: 25 female SLE patients without any cardiac symptoms and signs, and group 3: 25 female healthy controls-were evaluated by comparing rest and dipyridamole-stress Tc-99m TF myocardial perfusion SPECT. Tc-99m TF myocardial perfusion SPECT revealed perfusion defects in 88% and 40% of the cases in groups 1 and 2, respectively. However, no cases in group 3 demonstrated myocardial perfusion defects. Tc-99m TF myocardial perfusion SPECT is a useful noninvasive imaging modality to detect cardiac involvement in SLE patients with or without cardiac symptoms and signs. (author)

  20. Single photon emission computed tomography of technetium-99m tetrofosmin myocardial perfusion imaging in patients with systemic lupus erythematosus-A preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jen-Jhy; Hsu, Hsiu-Bao; Sun, Shung-Shung; Kao, Chia-Hung [China Medical Coll., Taichung, Taiwan (China). Hospital; Wang, Jhi-Joung [Chi-Mei Medical Center, Tainan, Taiwan (China); Ho, Shung-Tai [National Defense Medical Center, Taipei, Taiwan (China). School of Medicine

    2003-01-01

    The purpose of this study was to evaluate the utility of single-photon emission computed tomography (SPECT) of technetium-99m tetrofosmin (Tc-99m TF) myocardial perfusion imaging to detect myocardial involvement in patients with systemic lupus erythematosus (SLE). Three groups of subjects-group 1: 25 SLE female patients with non-specific cardiac symptoms and signs, group 2: 25 female SLE patients without any cardiac symptoms and signs, and group 3: 25 female healthy controls-were evaluated by comparing rest and dipyridamole-stress Tc-99m TF myocardial perfusion SPECT. Tc-99m TF myocardial perfusion SPECT revealed perfusion defects in 88% and 40% of the cases in groups 1 and 2, respectively. However, no cases in group 3 demonstrated myocardial perfusion defects. Tc-99m TF myocardial perfusion SPECT is a useful noninvasive imaging modality to detect cardiac involvement in SLE patients with or without cardiac symptoms and signs. (author)

  1. Quantification of myocardial infarct size by thallium-201 single-photon emission computed tomography: experimental validation in the dog

    International Nuclear Information System (INIS)

    To evaluate the potential advantages of thallium-201 (201T1) single-photon emission computerized tomography (SPECT) to assess myocardial infarct size in the experimental animal, six normal dogs and 14 dogs with 6 to 8 hr closed-chest coronary occlusion (eight left anterior descending and six left circumflex) were studied. Ten minutes after intravenous administration of 2 mCi of 201T1, 30 projections were obtained over 1800. The dogs were killed and their hearts sliced and stained by triphenyl tetrazolium chloride (TTC). Pathologic infarct size was calculated for each slice and for the entire left ventricular myocardium as percent weight. Tomograms were quantified by automatically generating maximum-count circumferential profiles, which were compared with normal limit profiles derived from the six normal dogs. Tomographic infarct size was defined as the percentage of circumferential points falling below normal for each tomogram. SPECT and TTC infarct size on 71 slices correlated highly (mean +/- SD 27.9 +/- 23.4% and 26.7 +/- 25.3%, respectively; r = .93, p less than .001, SEE = 9.4%). To determine SPECT infarct size as percent total left ventricular myocardial weight, infarct sizes from each slice were added to one another after each was multiplied by a coefficient that reflected the contribution of that slice to the total left ventricular weight. SPECT and TTC infarct size for the entire left ventricle correlated closely (mean +/- SD 20.5 +/- 7.6% and 19.3 +/- 8.3%, respectively; r = .86, p less than .001, SEE = 4.5%). It is concluded that 201T1 SPECT is a valid method for the noninvasive assessment of experimental myocardial infarct size

  2. Cardiofocal collimators for gated single-photon emission tomographic myocardial perfusion imaging

    International Nuclear Information System (INIS)

    In this article the feasibility and accuracy of gated SPET myocardial perfusion imaging using a triple-head camera equipped with CFC, is evaluated. Twenty patients with a history of myocardial infarction were studied. SPET myocardial perfusion images, gated in eight time bins, were acquired in a random sequence with a PHC and a CFC for each patient. Imaging was started 60 min after the injection of 925 MBq of technetium-99m tetrofosmin at rest. The extent (EXT) and severity (SEV) of perfusion defects were quantified on polar maps using the non-gated data. Left ventricular volumes [end-diastolic volume (EDV), end-systolic volume (ESV)] and ejection fraction (LVEF) were calculated from gated data using the Cedars-Sinai program. In 17 of 20 patients the complete left ventricle was positioned within the useful field of view of the CFC. The results in respect of perfusion, volumes and ejection fraction were almost identical to those obtained with the PHC. The mean difference±SD between the CFC and the PHC was -2.30±7.16 (% of LV area) for EXT, -0.48±2.90 for SEV (arbitrary units), -1,50±5.25 (ml) for EDV and 0.53±4.10 (%) for LVEF. The largest differences in EXT and LV volumes were observed in patients in whom a part of the LV was not positioned within the useful field of view. We conclude that, for the mfjority of patients, identical information with regard to both perfusion and function can be derived from gated SPET myocardial perfusion studies obtained with PHCs or with CFCs. Because of the greater sensitivity, however, a much shorter acquisition time is required with CFCs. (orig.)

  3. Comparative study of myocardial perfusion imaging by TL-201 single-photon ECT and N-13 ammonia positron CT

    International Nuclear Information System (INIS)

    Thallium (Tl) single-photon emission CT (SPECT) has been available for three-dimensional evaluation of myocardial perfusion. To assess the value and limitation of Tl SPECT, the images were compared with N-13 ammonia positron CT(PCT) in phantom and clinical studies. SPECT was performed by gamma camera rotation over 1800 after Tl 2 mCi injection. PCT was performed using 4 detector ring whole-body PCT device after N-13 ammonia 20 mCi injection. Acquisition time was 16 min for SPECT and 20 min (transmission) plus 10 min (emission) for PCT. No attenuation correction was done in SPECT, while in PCT it was accurately performed from the transmission data. Collected counts in a single slice were 100-180K by SPECT and 5-12M by PCT. The spatial resolution was about 16 mm for SPECT and 8 mm for PCT in FWHM. Because of better resolution and higher count statistics, PCT delineated fine cardiac structures, such as papillary muscles and apical thinning, while the myocardium looked thicker in SPECT due to poorer resolution. Regional distribution was comparatively evaluated by circumferential profile methods in the same plane in 5 normal cases. As compared to PCT, Tl distribution was less in the septal and posterior regions, and more in the lateral region due to photon attenuation. The authors conclude that Tl SPECT provides poorer images due to inadequate count density with poor resolution, as compared to PCT. It has severe limitation for quantitative evaluation of myocardial perfusion. However, one of the advantages of SPECT is that cardiac short-axis and long-axis sections can easily be reorganized

  4. The dobutamine stress Tl-201 myocardial single photon emission computed tomography for coronary artery stenosis caused by Kawasaki disease

    International Nuclear Information System (INIS)

    Noninvasive cardiac imaging with pharmacologic stress Tl-201 single photon emission computed tomography (SPECT) as an alternative to exercise test is now getting popular for patients with Kawasaki disease. Dobutamine infusion produces hemodynamic change which is quite similar to exercise induced hemodynamic change. Material consisted of 17 patients (13 males, 4 females) with coronary occlusion or significant coronary stenosis (?75% diameter stenosis) caused by Kawasaki disease. After step-wise infusion of dobutamine up to 40 ?g/kg/min., quantitative analysis of Tl-201 SPECT was obtained. No patient had a symptomatic arrhythmia or severely stress-induced ischemia. The sensitivity and specificity of dobutamine induced perfusion defects were 65% (11 to 17) and 92% (1 of 13) respectively. The sensitivity was 87% (7 of 8) in patients with the left coronary artery lesions and 46% (6 of 13) in patients with the right coronary artery lesions. We conclude that a quantitative analysis of Tl-201 SPECT after step-wise infusion of dobutamine is a safe and clinically useful method for detection of stress-induced myocardial ischemia in coronary artery stenosis caused by Kawasaki disease. (author)

  5. Myocardial sestamibi single-photon emission tomography: variations in reference values with gender, age and rest versus stress?

    International Nuclear Information System (INIS)

    Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise 99mTc-sestamibi SPET with a 2-day protocol and 180 elliptical rotation. The normalized activity values of 99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in 99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary. (orig.). With 3 figs., 3 tabs

  6. Transverse CAT of the myocardium with 201 Tl

    International Nuclear Information System (INIS)

    A new computerized axial tomographic (CAT) scanner (J and P Tomoscanner) which enables the transverse section viewing of any organ labelled by one of the monophotonic gamma-ray emitting tracers commonly used in Nuclear Medicine, has been recently commercialized. Its abilities in visualing the 201 Tl labelled myocardium are evaluated with normal hearts and patients with documented infarctions. Positive results have been obtained, allowing an interesting approach to the estimation of the anatomical extent of necrosis. (orig.) 891 MG/orig. 892 MBE

  7. Non-invasive evaluation of myocardial reperfusion by transthoracic Doppler echocardiography and single-photon emission computed tomography in patients with anterior acute myocardial infarction

    Directory of Open Access Journals (Sweden)

    Celutkiene Jelena

    2011-05-01

    Full Text Available Abstract Background The study was designed to evaluate whether the preserved coronary flow reserve (CFR 72 hours after reperfused acute myocardial infarction (AMI is associated with less microvascular dysfunction and is predictive of left ventricular (LV functional recovery and the final infarct size at follow-up. Methods In our study, CFR was assessed by transthoracic Doppler echocardiography (TDE in 44 patients after the successful percutaneous coronary intervention during the acute AMI phase. CFR was correlated with contractile reserve assessed by low-dose dobutamine echocardiography and with the total perfusion defect measured by single-photon emission computed tomography 72 hours after reperfusion and at 5 months follow-up. The ROC analysis was performed to determine test sensitivity and specificity based on CFR. Categorical data were compared by an ?2 analysis, continuous variables were analysed with the independent Student's t test. In order to analyse correlation between CFR and the parameters of LV function and perfusion, the Pearson correlation analysis was conducted. The linear regression analysis was used to assess the relationship between CFR and myocardial contractility as well as the final infarct size. Results We estimated the CFR cut-off value of 1.75 as providing the maximal accuracy to distinguish between patients with preserved and impaired CFR during the acute AMI phase (sensitivity 91.7%, specificity 75%. Wall motion score index was better in the subgroup with preserved CFR as compared to the subgroup with reduced CFR: 1.74 (0.29 vs. 1.89 (0.17 (p Conclusion The early measurement of CFR by TDE can be of high value for the assessment of successful reperfusion in AMI and can be used to predict LV functional recovery, myocardial viability and the final infarct size.

  8. Comparative evaluation of some analyses of stress-redistribution thallium-201 myocardial SPECT for myocardial ischemia

    International Nuclear Information System (INIS)

    Stress-redistribution thallium-201 (201Tl) myocardial single photon emission CT was performed in 55 patients with effort angina and 10 normal subjects. Visual interpretation and some quantitative expressions, which were maximum-count circumferential profile for myocardial distribution of 201Tl, segmental washout rate and each Bull's eye display, were analyzed to evaluate detectability for the territories of stenotic coronary arteries. The sensitivity of the visual method for detection of disease in LAD and RCA was fairly good and the specificity in each of the coronary artery was the highest in every analyses. However, the sensitivity for LCX and detectability in patient with multiple vessel disease were low. Accuracies of circumferential profile analysis and two Bull's eye display were equal or low as compared with visual method. Sensitivity of segmental washout rate was the highest value in every analyses and showed good results even in the patient with LCX lesion or multiple vessel disease. Washout rate score, which was calculated as the area between the washout rate profile curve and normal lower limits in the abnormal region, correlated well with severity of % coronary artery lumen diameter reduction. So we conclude that the visual method in combination with washout rate analysis is useful diagnostic method for detecting and evaluating patient with effort angina. (author)

  9. Effect of ribose on thallium-201 myocardial redistribution

    International Nuclear Information System (INIS)

    Myocardial 201Tl redistribution after transient ischemia may be too slow to allow identification of a reversible myocardial defect within the routine 201Tl imaging period. To determine whether 201Tl redistribution could be affected by a metabolic intervention, intravenous ribose was administered postischemia. Seventeen domestic swine were subjected to a 10-min ischemic period followed by either a 30-min i.v. ribose (n = 8) or saline (n = 9) infusion. Thallium-201 was injected during ischemia and myocardial 201Tl activity was continuously monitored in ischemic and nonischemic regions with miniature CdTe radiation detection probes. Coronary flow in the ischemic region was reduced to 25% of that in the nonischemic regions in both saline and ribose groups. The 201Tl time-activity curves demonstrated a significant enhancement of % 201Tl redistribution in the ribose-treated animals at the end of ribose infusion: Ribose (48 +/- 11%), Saline (20 +/- 4%), p less than 0.05. Alteration of 201Tl kinetics by ribose may permit earlier recognition of 201Tl myocardial redistribution after transient ischemia

  10. Comparison of post-exercise and post-vasodilator stress myocardial stunning as assessed by electrocardiogram-gated single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m (99mTc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning. To evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent 99mTc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall motion were evaluated. Post-stress myocardial stunning occurred in 24 patients (13%): 22 after exercise and 2 after ATP stress. The magnitude of the transient wall motion abnormality after exercise was greater in patients with severe ischemia, compared with those with mild-to-moderate ischemia (p99mTc-sestamibi gated SPECT, myocardial stunning is frequently observed after exercise and correlates with the severity of myocardial ischemia, but this does not occur with ATP, which is regarded as a specific marker for severe CAD. (author)

  11. The progress of assessment of myocardial viability by delayed-enhanced magnetic resonance imaging and positron emission tomography and single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Coronary artery disease (CAD)is one of the most common diseases that results in the different degree of myocardial damage. Thus, only viable myocardium in patients can get benefit from the myocardial revascularization. The accurate differentiation of viable and nonviable myocardium is crucial for therapy planning in patients with coronary artery disease and left ventricular dysfunction. Clinically, traditional techniques such as echocardiography, positron emission tomography, and single photon emission computed tomography have established roles. With the recent MRI technical developments allowing for a combined assessment of perfusion and irreversible damage with late enhancement imaging, MRI will now play a major role in the assessment of myocardial viability. Through the technique of delayed-enhancement MRI (DE-MRI), viable and infarcted myocardium can be simultaneously identified in a manner that closely correlates with histopathology findings. (authors)

  12. Clinical usefulness of 201Tl-chloride scintigraphy for the diagnosis of bone metastases

    International Nuclear Information System (INIS)

    Fifty-five patients with bone lesions underwent 201Tl-chloride (201Tl) scintigraphy to evaluate its findings and usefulness for the diagnosis of bone metastases. 201Tl scintigraphy was performed 15 minutes (early scan) and 2 hour (delayed scan) after iv injection of 5.55 MBq/kg of 201Tl-chloride. To evaluate the degree of tracer retention at the lesions, we calculated retention index after setting regions of interest in each lesion demonstrated tracer uptake in both early and delayed scans. Among 118 pathologically and/or clinically comfirmed bone metastases, 201Tl planar images disclosed 90 (76.3%) and 88 (74.6%) lesions on early and delayed scans, respectively. SPECT images were preferable for the evaluation of the lesions in the spine, thoracic cage and pelvis. Correlation of tumor size with findings on 201Tl images demonstrated 90.5% sensitivity for the metastases more than 7 cm3. No correlational difference was seen in the sensitivity depending on primary cancers. The overall retention index of bone metastases was -21.4±47.1. Bone metastases of pulmonary adenocarcinomas and small cell carcinomas demonstrated higher retention index than pulmonary squamous cell carcinomas and breast cancers. On 201Tl images, no abnormal tracer uptake was seen in benign lesions detected by 99mTc-hydroxymethylene diphosphonate (99mTc-HMDP) images except 5 lesions. The retention index of the benign lesions demonstrated abnormal uptakes of -48.3±15.9 on 201Tl images, showing no significant difference between that of metastases. For vertebral compression fractures, abnormal tracer uptakes were demonstrated in 9 of the 12 pathologic fractures against 2 of the 10 benign ones. Those 2 benign fractures proved to be vertebral tuberculosis. The results suggest 201Tl scintigraphy can find out false positive lesions of 99mTc-HMDP scintigraphy and contribute to diagnosis of bone metastases with combination of other images. (author)

  13. Statistical indices of 201Tl distribution in the myocardium in various diseases

    International Nuclear Information System (INIS)

    A study was made of the diagnostic potentialities of a histogram analysis of scintillation counting distribution on myocardium scans using 201Tl in 9 patients with dilatational cardiomyopathy, 12 patients with coronary heart disease and 6 patients with primary pulmonary hypertension. Scans were recorded 10 min., 4 and 24 h after a single administration of 201Tl at rest in the front-forward, 45 deg left forward oblique and left lateral projections. The author showed a possibility of group distinction by scintillation counting distribution in the heart area on myocardium scans using 201Tl, the distinguishing information being within the interval of 41-80% of maximum intensity in this area

  14. Myocardial perfusion abnormality and effects of Ca channel blockers on myocardial ischemia in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the frequency of myocardial ischemia and characteristic regions of myocardial hypoperfusion during stress in patients with hypertrophic cardiomyopathy. Furthermore, the effects of Ca channel blocker (verapamil, diltiazem) on myocardial ischemia were studied. One hundred patients with hypertrophic cardiomyopathy underwent exercise 201Tl SPECT. Sixty-eight patients had one or more 201Tl abnormalities. Of the 68 patients with 201Tl abnormalities, 56 had reversible 201Tl abnormalities and 12 had fixed defect. 201Tl abnormalities were frequently distributed in the anterior and posterior areas of junction between the ventricular septum and the free wall and the apex. Of the 56 patients with reversible 201Tl abnormalities, 40 patients underwent one more exercise 201Tl SPECT after 8 weeks of oral administration of verapamil or diltiazem. The 201Tl defect was visually scored as the defect score. Transient dilation index was calculated as an index of subendocardial ischemia. The mean defect score decreased significantly from 9.80±4.35 to 5.50±4.63 after verapamil and from 9.90±5.17 to 5.50±4.89 after diltiazem. Mean transient dilation index decreased from 1.20±0.12 to 1.08±0.09 after treatment with verapamil and from 1.16±0.10 to 1.02±0.09 after treatment with diltiazem. (K.H.)

  15. Myocardial metabolic, hemodynamic, and electrocardiographic significance of reversible thallium-201 abnormalities in hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, R.O. 3d.; Dilsizian, V.; O' Gara, P.T.; Udelson, J.E.; Schenke, W.H.; Quyyumi, A.; Fananapazir, L.; Bonow, R.O. (National Institutes of Health, Bethesda, MD (USA))

    1991-05-01

    Exercise-induced abnormalities during thallium-201 scintigraphy that normalize at rest frequently occur in patients with hypertrophic cardiomyopathy. However, it is not known whether these abnormalities are indicative of myocardial ischemia. Fifty patients with hypertrophic cardiomyopathy underwent exercise {sup 201}Tl scintigraphy and, during the same week, measurement of myocardial lactate metabolism and hemodynamics during pacing stress. Thirty-seven patients (74%) had one or more {sup 201}Tl abnormalities that completely normalized after 3 hours of rest; 26 had regional myocardial {sup 201}Tl defects, and 26 had apparent left ventricular cavity dilatation with exercise, with 15 having coexistence of these abnormal findings. Of the 37 patients with reversible {sup 201}Tl abnormalities, 27 (73%) had metabolic evidence of myocardial ischemia during rapid atrial pacing compared with four of 13 patients (31%) with normal {sup 201}Tl scans (p less than 0.01). Eleven patients had apparent cavity dilatation as their only {sup 201}Tl abnormality; their mean postpacing left ventricular end-diastolic pressure was significantly higher than that of the 13 patients with normal {sup 201}Tl studies (33 +/- 5 versus 21 +/- 10 mm Hg, p less than 0.001). There was no correlation between the angiographic presence of systolic septal or epicardial coronary arterial compression and the presence or distribution of {sup 201}Tl abnormalities. Patients with ischemic ST segment responses to exercise had an 80% prevalence rate of reversible {sup 201}Tl abnormalities and a 70% prevalence rate of pacing-induced ischemia. However, 69% of patients with nonischemic ST segment responses had reversible {sup 201}Tl abnormalities, and 55% had pacing-induced ischemia. Reversible {sup 201}Tl abnormalities during exercise stress are markers of myocardial ischemia in hypertrophic cardiomyopathy and most likely identify relatively underperfused myocardium.

  16. Myocardial metabolic, hemodynamic, and electrocardiographic significance of reversible thallium-201 abnormalities in hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Exercise-induced abnormalities during thallium-201 scintigraphy that normalize at rest frequently occur in patients with hypertrophic cardiomyopathy. However, it is not known whether these abnormalities are indicative of myocardial ischemia. Fifty patients with hypertrophic cardiomyopathy underwent exercise 201Tl scintigraphy and, during the same week, measurement of myocardial lactate metabolism and hemodynamics during pacing stress. Thirty-seven patients (74%) had one or more 201Tl abnormalities that completely normalized after 3 hours of rest; 26 had regional myocardial 201Tl defects, and 26 had apparent left ventricular cavity dilatation with exercise, with 15 having coexistence of these abnormal findings. Of the 37 patients with reversible 201Tl abnormalities, 27 (73%) had metabolic evidence of myocardial ischemia during rapid atrial pacing compared with four of 13 patients (31%) with normal 201Tl scans (p less than 0.01). Eleven patients had apparent cavity dilatation as their only 201Tl abnormality; their mean postpacing left ventricular end-diastolic pressure was significantly higher than that of the 13 patients with normal 201Tl studies (33 +/- 5 versus 21 +/- 10 mm Hg, p less than 0.001). There was no correlation between the angiographic presence of systolic septal or epicardial coronary arterial compression and the presence or distribution of 201Tl abnormalities. Patients with ischemic ST segment responses to exercise had an 80% prevalence rate of reversible 201Tl abnormalities and a 70% prevalence rate of pacing-induced ischemia. However, 69% of patients with nonischemic ST segment responses had reversible 201Tl abnormalities, and 55% had pacing-induced ischemia. Reversible 201Tl abnormalities during exercise stress are markers of myocardial ischemia in hypertrophic cardiomyopathy and most likely identify relatively underperfused myocardium

  17. Evaluation of thallium-201 washout in patients with ischemic heart disease using ring-type single photon emission CT

    International Nuclear Information System (INIS)

    With the emergence of single photon emission computed tomography (SPECT), thallium-201 (Tl) myocardial scanning has become the important diagnostic procedure of choice for ischemic heart disease; however, clinical and diagnostic aspects still remain unclear. The present study explored kinetics of Tl within the myocardium using ring-type SPECT that allows rapid sequential scanning. Three groups containing five patients with effort angina pectoris (EAP), old myocardial infarction (OMI), or chest pain syndrome (CPS), were scanned during exercise five times at five min intervals after injection of 2.5 - 4.0 mCi of Tl, and subsequently scanned at one, two, and three hr later. Time-activity curves and washout rates in five regions of interest were examined. At 30 min, washout rate was 10 % in the EAP and OMI groups and 0.2 % in the CPS group, showing significant difference between the former two groups and the latter group. This implies that ring-type SPECT may play an important role in elucidating the mechanism of Tl washout and myocardial blood flow, although it has still disadvantages of limited transaxial three scans and inability to correct scattered rays. (Namekawa, K.)

  18. Clinical evaluation of 201Tl-chloride scintigraphy for breast tumors

    International Nuclear Information System (INIS)

    Fifty-two patients with breast tumors were scintigraphed with 201Tl-chloride. Each one was given a histological diagnosis after surgery or excisional biopsy. In 39 cases of primary breast cancer, 27 cases (69.2 %) showed a positive figure by 201Tl-chloride scintigraphy. In five cases of local recurrent breast cancer, four cases (80 %) showed a positive figure. In examining each histological type of primary breast cancer, in 10 cases of papillotubular carcinoma, seven (70 %) were positive with 201Tl-chloride. In 20 patients with medullary tubular carcinoma, 17 cases (85 %) revealed a positive figure. In nine cases of scirrhous carcinoma, only three cases (33.3 %) were positive. Some cases showed an accumulation in the metastatic lymph nodes of the axilla with 201Tl-chloride. In three cases of phyllodes tumor, two cases (66.7 %) were positive. On the other hand, all cases of benign breast tumors showed a negative figure by 201Tl-chloride scintigraphy. As to the uptake ratio of 201Tl-chloride into the breast carcinoma tissue, it was observed that papillotubular carcinoma absorbed 5.8 times as much as normal mammary gland tissue, medullary tubular carcinoma absorbed 4.7 times as much, scirrhous carcinoma absorbed 3.3 times as much as normal mammary gland tissue. In recurrent breast cancer, 201Tl-chloride scintigraphy is a useful procedure in determining the malignant area and in judging the effect of treatment. From the above mentioned results, it was concluded that 201Tl-chloride has specific affinity for malignant breast tumors and it is also very useful tumor-seeking agent to detect the early recurrent breast cancer. (author)

  19. Effect of diltiazem on myocardial infarct size estimated by enzyme release, serial thallium-201 single-photon emission computed tomography and radionuclide angiography

    International Nuclear Information System (INIS)

    Diltiazem is a calcium antagonist with demonstrated experimental cardioprotective effects. Its effects on myocardial infarct size were studied in 34 patients admitted within 6 hours after the first symptoms of acute myocardial infarction. These patients were randomized, double-blind to placebo or diltiazem (10-mg intravenous bolus followed by 15 mg/hr intravenous infusion during 72 hours, followed by 4 X 60 mg during 21 days). Myocardial infarct size was assessed by plasma creatine kinase and creatine kinase-MB indexes, perfusion defect scores using single-photon emission computed tomography with thallium-201 and left ventricular ejection fraction measured by radionuclide angiography. Tomographic and angiographic scanning was performed serially before randomization, after 48 hours and 21 days later. Groups were comparable in terms of age, sex, inclusion time and baseline infarct location and size. Results showed no difference in creatine kinase and creatine kinase-MB data between controls and treated patients, a significant decrease in the perfusion defect scores in the diltiazem group (+0.1 +/- 3.0 placebo vs -2.2 +/- 1.9 diltiazem, p less than 0.02) and a better ejection fraction recovery in the diltiazem group (-4.2 +/- 7.4 placebo vs +7.7 +/- 11.2 diltiazem, p less than 0.05). Myocardial infarct size estimates from perfusion defect scores and enzyme data were closely correlated. These preliminary results suggest that diltiazem may reduce ischemic injury in acute myocardial infarction

  20. Dual myocardial single photon emission computed tomography (SPECT) using thallium-201 and I-123-?-methyl-i-pentadecanoic acid in patients with Duchenne's progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Dual single photon emission computed tomography (SPECT) was performed in 31 patients with Duchenne's progressive muscular dystrophy (DMD) using 123I-?-methyl pentadecanoic acid (BMIPP) for myocardial fatty acid metabolism and 201thallium (Tl)-chloride for myocardial perfusion. The left ventricle was divided into 9 segments, and accumulation of the radiotracers was assessed visually for each segment to calculate defect score for each tracer. There was some degree of decrease in myocardial accumulation of both tracers in all DMD patients. Reduced accumulation was most common at the apex (BMIPP: 67%, Tl: 63%), followed by the posterior wall, lateral wall, and anterior wall. On the other hand, reduced accumulation was less common at the septum. BMIPP showed a higher accumulation than Tl in all segments but the septum. When BMIPP defect score was larger than Tl defect score, BMIPP defect score tended to increase during 4 years follow-up (p Tl defect score revealed a slight fibrosis or normal myocardium. It can be concluded that the dual SPECT myocardial scintigraphy using BMIPP and Tl provides accurate information about disease progression of the heart in patients with DMD by detecting abnormalities of the myocardial metabolism of each substance, thereby enabling the assessment of left ventricular function. (author)

  1. Stress 201Tl-scintigraphy of the myocardium - comparison with veloergometry and selective coronary arteriography in patients with chronic ischeemic heart disease

    International Nuclear Information System (INIS)

    The study has been carried out on 53 patients with complaints of pain with anterior thoracal localization, clinically diagnosed as stable angina pectoris at mild physical efforts; 31 of the patients had a case history of passed myocardial infarction. All patients have been subjected to right-and left-side cardiac catheterization, left ventricular ventriculography and standard selective coronary arteriography 3 to 20 days before or after stress scintigraphy (SS) with 201Tl-chloride. SS is carried out on a static veloergometer by stepwise loading; every 6 min a registration of the 6 thorax ECG-deviations is made and the arterial pressure is mesured. 201Tl-chloride (74 MBk) is injected at the pick of the physical burden. The myocardial perfusion is visualized on 'Nuclear Ohio' gamma camera with a parallel collimator in 3 projections in the course of 6 min for each projection, which allows to evaluate the perfusion of 9 segments of the myocardium. Two hours after the physical loading the myocardial perfusion at rest is studied by the same method. The comparative study shows a considerable advantage of the Tl-SS compared to veloergometry of patients with insignificant haemodynamic coronary stenosis: it allows a precise evaluation of the myocardial perfusion in cases when the appraisal of ECG-changes after a physical loading is difficult. 3 tabs., 5 refs

  2. Effects of CT-based attenuation correction of rat microSPECT images on relative myocardial perfusion and quantitative tracer uptake

    International Nuclear Information System (INIS)

    Purpose: Our goal in this work was to investigate the impact of CT-based attenuation correction on measurements of rat myocardial perfusion with 99mTc and 201Tl single photon emission computed tomography (SPECT). Methods: Eight male Sprague-Dawley rats were injected with 99mTc-tetrofosmin and scanned in a small animal pinhole SPECT/CT scanner. Scans were repeated weekly over a period of 5 weeks. Eight additional rats were injected with 201Tl and also scanned following a similar protocol. The images were reconstructed with and without attenuation correction, and the relative perfusion was analyzed with the commercial cardiac analysis software. The absolute uptake of 99mTc in the heart was also quantified with and without attenuation correction. Results: For 99mTc imaging, relative segmental perfusion changed by up to +2.1%/?1.8% as a result of attenuation correction. Relative changes of +3.6%/?1.0% were observed for the 201Tl images. Interscan and inter-rat reproducibilities of relative segmental perfusion were 2.7% and 3.9%, respectively, for the uncorrected 99mTc scans, and 3.6% and 4.3%, respectively, for the 201Tl scans, and were not significantly affected by attenuation correction for either tracer. Attenuation correction also significantly increased the measured absolute uptake of tetrofosmin and significantly altered the relationship between the rat weight and tracer uptake. Conclusions: Our results show that attenuation correction has a small but statistically significant impact on the relative perfusion measurements in some segments of the heart and does not adversely affect reproducibility. Attenuation correction had a small but statistically significant impact on measured absolute tracer uptake

  3. Clinical studies on thallium-201 myocardial perfusion imaging in patients with ischemic heart disease

    International Nuclear Information System (INIS)

    201Tl myocardial perfusion imaging in patients with ischemic heart disease was discussed. Infarcted areas, which had been diagnosed with electrocardiograms and coronary arteriograms of 27 patients with cardial infarction, were visualized as a decrease or a defect of myocardial uptake of 201Tl on their rest myocardial perfusion images (MPI). The pictures of them obtained from rest MPI were well correlated with their coronary arteriograms. Myocardial uptake of 201Tl was increased by exercise in normal subjects, but decreased uptake of RI was observed on stress MPI of 12 patients with effort angina and 5 of 6 patients with cardial infarction. These findings were also observed in their postexertion electrocardiogram. To visualize images more clearly, an phantom experiment was performed and clear images close to the actual size were obtained. Ratio of myocardial uptake of 201Tl in ischemic areas after exercise was decreased significantly in patients with angina and cardiac infarction, though myocardial uptake of 201Tl in healthy subjects was not changed by exercise. A defect of myocardial uptake of 201Tl was induced by methacholine in 4 patients with a variant form of angina and was induced by exercise in 2. Improvement of myocardial uptake of 201Tl was observed on images of patients in whom blood flow in local myocardium had been improved after the operation to make bypass. (Tsunoda, M.)

  4. Different thallium-201 single-photon emission tomographic patterns in benign and aggressive meningiomas

    Energy Technology Data Exchange (ETDEWEB)

    Tedeschi, E. [Dipartimento di Diagnostica per Immagini, Centro CNR per la Medicina Nucleare, Napoli (Italy); Soricelli, A. [Dipartimento di Diagnostica per Immagini, Centro CNR per la Medicina Nucleare, Napoli (Italy); Brunetti, A. [Dipartimento di Diagnostica per Immagini, Centro CNR per la Medicina Nucleare, Napoli (Italy); Romano, M. [Dipartimento di Diagnostica per Immagini, Centro CNR per la Medicina Nucleare, Napoli (Italy); Bucciero, A. [Istituto di Neurochirurgia, Universita `Federico II`, Napoli (Italy); Iaconetta, G. [Istituto di Neurochirurgia, Universita `Federico II`, Napoli (Italy); Alfieri, A. [Istituto di Neurochirurgia, Universita `Federico II`, Napoli (Italy); Postiglione, A. [Dipartimento di Clinica Medica, Universita `Federico II`, Napoli (Italy); Salvatore, M. [Dipartimento di Diagnostica per Immagini, Centro CNR per la Medicina Nucleare, Napoli (Italy)

    1996-11-01

    To evaluate the possibility of preoperatively obtaining an index of aggressiveness for intracranial meningiomas, we prospectively studied 22 patients with computed tomographic or magnetic resonance imaging evidence of meningeal tumour, using single-photon emission tomography (SPET) of the brain and thallium-201 ({sup 201}Tl). On a brain-dedicated SPET scanner, a rapid acquisition protocol with early, short scans was started simultaneously with the intravenous administration of 111 MBq {sup 201}Tl, covering the initial intratumoral distribution of the tracer. Twenty minutes post injection, a delayed SPET scan was also obtained. On the reconstructed and attenuation-corrected images we calculated the {sup 201}Tl concentration in tumour and normal contralateral brain tissue, and compared intratumoral tracer concentration in the initial and the final part of the rapid acquisition protocol. Benign and malignant meningiomas were classified as such based on histological examination. In malignant lesions, the ratio of the {sup 201}Tl concentration at 2-4 min post injection to that at 14-16 min was found to be significantly higher than in non-aggressive neoplasms (mean{+-}1 SD: 1.14{+-}0.31 and 0.56{+-}0.13, respectively, P <0.01). Conversely, in the delayed scan, most lesions showed high tracer concentration, and the two groups could not be distinguished. In addition, three recurrent meningiomas displayed the same imaging behaviour as the malignant group, i.e. had similar {sup 201}Tl concentration values at 2-4 and at 14-16 min. Our findings suggest that the comparative assessment of intratumoral {sup 201}Tl concentration at 2-4 and at 14-16 min post injection could provide a fast, simple method to differentiate preoperatively intracranial meningiomas with different biological behaviour. (orig.). With 3 figs., 1 tab.

  5. Comparison of flow capacities of arterial and venous grafts for coronary artery bypass grafting: evaluation with exercise thallium-201 single-photon emission tomography

    International Nuclear Information System (INIS)

    Stress thallium-201 tomography was performed to compare the flow capacities of arterial and saphenous vein grafts in patients with coronary artery bypass grafting (CABG). One hundred and seven consecutive patients (95 male and 12 female; mean age 58±9.1 years) underwent exercise-redistribution 201Tl myocardial single-photon emission tomography 4-5 weeks after CABG. When a reversible perfusion defect was present in the area covered by a patent bypass graft, the flow capacity of the graft was defined as insufficient. Of all 285 grafts, 211 were considered as complete bypass. Reversible perfusion defects were present in 29 (27%) of 108 myocardial areas supplied by patent arterial grafts but in only 5 (5%) of 103 myocardial areas supplied by patent saphenous vein grafts (P<0.0001). In the LAD area reversible defects were observed in 22 of 82 areas covered by arterial grafts, in contrast to only 1 of 29 areas covered by venous grafts (P<0.01); in the RCA area reversible defects were observed in 7 of 17 and 4 of 41 areas respectively (P<0.01). There was no difference between the native coronary artery stenosis bypassed by patent arterial and venous grafts (88%±12% vs 86%±14% respectively, P=0.27). In conclusion, flow capacities during peak myocardial demand were more frequently insufficient in arterial bypass grafts than in saphenous vein grafts. (orig.)

  6. Effects of exercise training on myocardial fatty acid metabolism in rats with depressed cardiac function induced by transient ischemia

    International Nuclear Information System (INIS)

    The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wistar Kyoto rats were subjected either to a 30-min left coronary artery occlusion followed by reperfusion or to a sham operation. At 4 weeks after operation, the rats were randomly assigned either to sedentary conditions or to exercise training for 6 weeks. In the ischemic rats, pinhole SPECT (single photon emission computed tomography) imaging with thallium-201 (201Tl) and 123I-(?-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) showed a reduction of both myocardial perfusion and fatty acid metabolism in the risk zone of the left ventricle (LV). The LV was dilated and the ejection fraction was decreased after ischemic injury. The severity score showed a significant decrease on both 201Tl and BMIPP (201Tl, from 19.9±2.7 to 17.0±2.2, p<0.05; BMIPP, from 21.5±2.4 to 18.6±1.9, p<0.05) after exercise training in the ischemic trained rats, but did not change significantly in their sedentary counterparts. Plasma levels of free fatty acids normalized in the ischemic trained rats, but elevated in the ischemic sedentary rats (0.53±0.05 vs 0.73±0.06 mmol/L, p<0.05). Furthermore, the trained rats had a significant increase in LV stroke volume (0.25±0.02 vs 0.21±0.01 ml/beat, p<0.05) and adaptive cardiac hypertrophy. These findings demonstrate that adaptive improvements in myocardial perfusion, fatty-acid metabolism and LV function were induced by exercise training after transient ischemia. (author)

  7. 99mTc-MIBI and 201Tl imaging of thyroid with cold nodule

    International Nuclear Information System (INIS)

    Objective: To investigate clinical value of 99mTc-MIBI and 201Tl imaging of thyroid with cold nodule. Methods: 87 patients with cold thyroid nodule were imaged with 99mTc-MIBI (early 15 min, delayed 60 min) and 201Tl (early 15 min, delayed 120 min). Results of interest (ROIs) were generated over the cold nodule and normal tissue on each image by semi-quantification method. The semi-quantitative analysis was performed by using a lesion to non-lesion ratio of early (ER) and delayed (DR) images. Retention index (RI) was calculated by dividing delayed-early subtraction to product ER. Results: there was significant difference in the ER, DR and RI between malignant and benign lesions for 99mTc-MIBI and 201Tl (p0.05), but there was significant difference between carcinoma and cystic adenoma for 201Tl imaging (p99mTc-MIBI and 201Tl imaging of thyroid cold nodule using ER, DR and RI have good clinical application value

  8. Assessment of ischemic heart disease by dipyridamole stress electrocardiographic gated myocardial single photon emission computed tomography with technetium-99m tetrofosmin

    International Nuclear Information System (INIS)

    Simultaneous assessment of stress perfusion and rest function is possible with gated single photon emission computed tomography (SPECT) using stress injected technetium-99m (99mTc) tetrofosmin (TF). The feasibility of dipyridamole stress electrocardiographic gated myocardial SPECT (GSPECT) with TF was examined as an alternative to conventional stress/rest imaging. Fifty-one patients underwent stress GSPECT. 740 MBq of TF was administered 3 min after dipyridamole infusion. GSPECT acquisition was performed one hour after the injection. Additional rest SPECT was performed on another day only in patients with abnormal perfusion on stress images. Perfusion and thickening were analyzed visually on 17 segments of the left ventricle. Percentage of wall thickening (%WT) was also calculated in 17 segments of the polar map. Thirty-two of 51 patients (63%) had normal stress perfusion and normal rest thickening. Nineteen of 51 patients (37%) had abnormal perfusion on stress images. Among 157 abnormal perfusion segments of the 19 patients, 139 segments (89%) had thickening and the rest (11%) had no thickening. %WT was higher in the reversible segments with or without thickening. There was better agreement for the identification of normal segments and the presence of reversibility between stress GSPECT and the conventional stress/rest study in patients without previous myocardial infarction than in those with previous myocardial infarction (89% vs 79%). These results suggest that stress GSPECT may substitute for conventional stress/rest perfusion study in patients without previous myocardial infarction, allowing shorter examination time and lower cost. However, stress GSPECT does not replace the need for rest perfusion study in patients with previous myocardial infarction, because of underestimation of viability, but %WT may eliminate this underestimation. (author)

  9. Study of the predictors and lesion characteristics of ischemic heart disease patients with false negative results in stress myocardial perfusion single-photon emission tomography

    International Nuclear Information System (INIS)

    The predictors and lesion morphology of patients with ischemic heart disease testing false negative results in stress myocardial perfusion single-photon emission computed tomography (SPECT) was investigated. Subjects were 58 consecutive patients who underwent coronary angiography (CAG), even though they showed normal findings in stress myocardial perfusion SPECT. Age, gender, methods of stress, perfusion agent, coronary risk factors, angina symptoms, and electrocardiographic changes were investigated as predictors by multivariate analysis. For lesion morphology, significant stenotic lesions were studied for morphological characteristics and reference diameter (RD), percentage diameter stenosis (%DS), minimum lumen diameter (MLD), and lesion length (LL) were measured. CAG revealed 30 significant stenotic lesions in 18 patients. Logistic regression analysis revealed significant predictors to be age (odds ratio (OR) 1.118, p<0.05), typical anginal pain (OR 21.09, p<0.01), and hypertension (OR 8.336, p<0.05). For lesion morphology, there were only 2 diffuse lesions and the mean RD, %DS, MLD, and LL were 3.03±0.9 mm, 63.1±9.3%, 1.13±0.49 mm, and 13.2±7.0 mm, respectively. Sufficient caution is believed necessary in the interpretation of normal findings of stress myocardial perfusion SPECT when the patient is elderly, complains of typical anginal pain, or has hypertension. In regard to characteristics of lesion morphology, there were hardly any diffuse lesions. (author)

  10. Prognostic value of post-ischemic stunning as assessed by gated myocardial perfusion single-photon emission computed tomography. A subanalysis of the J-ACCESS study

    International Nuclear Information System (INIS)

    To determine the prognostic value of post-ischemic stunning, the Japanese assessment of cardiac event and survival study by quantitative gated myocardial single-photon emission computed tomography (SPECT) (J-ACCESS) study was reevaluated. Of the 4,031 patients of the J-ACCESS, the present study evaluated 1,089 who completed gated SPECT both after stress and at rest. To assess post-ischemic stunning, the following measurements (left ventricular volumes after stress minus volumes at rest) were made: ?end-systolic volume (?ESV), ?end-diastolic volume (?EDV) and ?ejection fraction (?EF). Myocardial stunning defined either as ?ESV ?5 ml, ?EDV ?5 ml or ?EF ?-5% was observed in 21%, 22%, or 26%, respectively. During a 3-year follow-up, 101 cardiac events occurred. Kaplan-Meier survival estimation indicated worse event-free survival rates in patients with dilated ESV, dilated EDV, left ventricular ejection fraction (LVEF) ?45% ?ESV ?5 ml or ?EDV ?5 ml than in those without, whereas ?EF ?-5% did not predict events. Multivariate analysis demonstrated that LVEF ?45% was the independent predictor for cardiac events. Nevertheless, ?EDV ?5 ml was also an independent parameter, in addition to LVEF ?45%, to predict the combined endpoint of cardiac death, myocardial infarction, and revascularization, but excluding heart failure. These results indicate that post-ischemic stunning, as assessed by gated SPECT, is a marker for poor prognosis, particularly for ischemic cardiac events. (author)

  11. Evaluation of cellular viability by quantitative autoradiographic study of myocardial uptake of a fatty acid analogue in isoproterenol-induced focal rat heart necrosis

    International Nuclear Information System (INIS)

    Previous studies led us to hypothesize that a fatty acid analogue, 15-p-iodophenyl-?-methyl pentadecanoic acid (IMPPA or BMIPP), which is taken up but not quickly metabolized by heart cells, would be a more suitable tracer of cellular viability that 201Tl. Biodistribution studies of 1-14C-IMPPA in conscious, freely moving rats showed that the concentration ratio of radioactivity in the heart with respect to the blood was about 8 for at least 60 min after intravenous administration, permitting its use as a putative tracer in these conscious, freely moving rats. Thereafter, the myocardial uptake of 14C-IMPPA was studied in isoproterenol-treated rats (daily treatment for 10 days in order to induce cardiac hypertrophy and necrotic foci) with respect to control ones. Comparison of myocardial localizations by quantitative autoradiography of the uptake of 201Tl and 14C-IMPPA with that of triphenyltetrazolium chloride (TTC) staining enabled comparative evaluation of nutritional blood flow, localization and uptake of 14C-IMPPA and necrotic foci size. Distributions of 14C-IMPPA and 201Tl in control rats' hearts were homogenous, like TTC staining. In infarcted hearts, areas of decreased 14C-IMPPA uptake were nearly the same (100%±5%) as those unstained by TTC. These areas were larger than those showing a decrease in thallium uptake (about 70%±5% of the total scar size). Therefore, IMPPA seems to be a more accurate and sensitive indicator of necrosis localization compared with thallium. It may be a useful agent for assessment of myocardial viability by single photon emission tomography (SPET) imaging. (orig.)

  12. Reverse redistribution in dipyridamole-loading thallium-201 images using single photon emission computed tomography

    International Nuclear Information System (INIS)

    Dipyridamole was infused intravenously at a rate of 0.142 mg/kg per min for four min, and a stress image was obtained 10 min after the injection of two mCi 201Tl. The myocardial image of Tl was analyzed by single photon emission computed tomography and its washout rate was calculated by the segmental ROI method. Myocardial function and the motion of the left ventricular wall were analyzed by 99mTc-RBC-gated cardiac pool imaging. Reverse redistribution was noted in 27 (21.6 %) of 125 consecutive Tl dipyridamole and redistribution myocardial imaging studies. The stress image demonstrated normal perfusion (group 1) and reduced perfusion (group 2) of Tl. Group 1 consisted of 17 patients with diabetes mellitus, supraventricular arrhythmias, hypertension, and others. Group 2 consisted of 10 patients with subendocardial infarction, diabetes mellitus, and hypertension, and others. The percentage prevalence of reverse redistribution among patients with supraventricular arrhythmia was 62.5 % (five of eight patients), with subendocardial infarction 60.0 % (three of five), with hypertension 42.8 % (six of 14), and with diabetes mellitus 40.0 % (eight of 20), while in those with transmyocardial infarction and angina pectoris no reverse redistribution percentage was found. The washout rate of Tl in normal perfusion areas was 44.0 ± 12.8 %, the reverse redistribution of group 1 was 47.4 ± 12.8 %, and of group 2 was 51.2 ± 8.2 %. The washout rate of the reverse redistribution of group 2 was significantly greater than that of the normal areas. In gated cardiac pool imaging, patients in group 2 had significantly larger areas showing abnormal contraction of the left ventricular wall and significantly lower ejection fraction than did group 1. In the electrocardiogram ST segment depression was noted more frequently in group 2 than group 1. No Q wave was present in the corresponding reverse redistribution area. (J.P.N.)

  13. Evaluating the sensitivity and specificity of 201Tl SPECT in intracranial tumoral pathology

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the sensitivity of SPECT with 201Tl in detecting the cerebral tumors. A hundred and forty nine explorations were carried out (107 SPECT in patients clinically suspected and/or cerebral tumor radiography, 42 SPECT in patients treated for cerebral tumor to evaluate the persistence of the tumoral tissue immediately post-operation, or the presence of a tumoral recurrence). The SPECTs were achieved 15 minutes after the IV injection of 185 MBq of 201Tl with a double head Elscint Helix HR camera with fan collimators. The reconstructions were obtained by retro-projection with a Metz 3.13 filter. As the brain normally do not capture 201Tl, any fixation of 201Tl was considered an positive examination. The final diagnosis was based either on the histology (n = 41) or on clinical evolution (n = 149). The pathologies recorded were: 33 glial tumors, 32 metastases (51 lesions), 14 meningiomas, 1 hypophyseal adenoma, 1 cranio-pharyngogioma, 1 malign lymphoma, 1 gr.4 neurinomas, 1 arachnoid cyst, 34 AVCs, 24 normal, 2 complete surgical extirpations, and 5 necroses after treatment. In our population the sensitivity of SPECT with 201Tl for the diagnosis of intracranial tumors was calculated to be 91.5% and the specificity, 98.5%. We have met a false positive (recent hemorrhagic AVC) and 7 false negatives (4 metastases of which 3 were under 1 cm and another largely necrotic, 3 patients presenting residual tumoral tissue immediately post-operation, presently in recurrence). These excellent results prove the utility of SPECT with 201Tl both for positive diagnosis of cerebral tumors and for evaluation of these tumors after treatment

  14. Effects of exercise on kinetics and distribution of 43K and 201Tl in isolated myocardium: concise communication

    International Nuclear Information System (INIS)

    Kinetics and distribution of K-43 and Tl-201 were studied in isolated myocardial tissue from rats to assess the effects of exercise. The experimental design was as follows. Rats in some groups were forced to swim for 2 hr; immediately after swimming, they were injected with 0.2 mCi of 43KCl or 201TlCl; at 0.5 or 3 hr after injection they were killed and a myocardial segment was obtained and subjected to washouts with nonradioactive Krebs fluid in a special chamber. The radioactivity remaining in the tissue was recorded continuously for 1 hr. In control groups (''rested'') the exercise was omitted. Altogether there were four groups of ten animals each for both K-43 and Tl-201. A three-compartment model (extracellular, main intracellular, and subcellular) was used; transport rate constants and relative compartment sizes were determined. The most striking finding was the unchangeability of K-43 parameters with regard to experimental condition (rest compared with exercise) and sampling time (0.5 compared with 3 hr after radionuclide injection). On the other hand, Tl-201 parameters were modified by exercise and sampling time. Notable differences between K-43 and Tl-201 kinetics were found. The hypothesis that alterations at the cellular level may affect regional myocardial distribution of a radionuclide is discussed

  15. Estimation of Myocardial Ischemia by Diastolic Strain Analysis in Exercise Stress Echocardiography. Comparison with exercise thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    The feasibility of detecting persistent regional left ventricular abnormal relaxation due to myocardial ischemia using strain echocardiography several minutes after exercise was investigated. Consecutive 27 patients (mean age 65±9 years, 21 males, 6 females) with suspected coronary artery disease were enrolled. Strain echocardiographic images were acquired at the mid segments of the left ventricular wall before and 5 min after exercise in the apical long-axis, two-chamber and four-chamber views. Strain curves were obtained at each segment, and peak values of strain at the closure of aortic valve (A) and at one third of diastolic duration (B) were measured. Strain diastolic index (SDI) was calculated as (A-B)/A x 100%. The ratio of SDI before exercise to that after exercise was defined as the SDI ratio and compared with exercise thallium-201 single photon emission computed tomography (SPECT) as the reference standard to detect myocardial ischemia. A total of 162 segments were evaluated. Based on the results of exercise SPECT, 119 segments were classified as non-ischemic segments, and 43 as ischemic segments. Ischemic segments showed significant decreases in SDI before and after exercise, whereas non-ischemic segments showed no significant differences in SDI before and after exercise. SDI ratio was significantly decreased in ischemic segments, but not in non-ischemic segments. SDI ratio with a cut off value of 0.51 had a sensitivity of 91% and a specificity of 89% to detect myocardial ischemia in the receiver-operating characteristics. Strain echocardiography can provide quantitative assessment of myocardial ischemia by detecting post-ischemic regional left ventricular delayed relaxation even 5 min after exercise. (author)

  16. High-contrast film copying for 201Tl cardiac image processing

    International Nuclear Information System (INIS)

    To evaluate the usefulness of high-contrast film copying as an economical means of enhancing contrast in 201Tl cardiac images, stress and rest studies of 47 patients with and 19 patients without coronary artery disease were evaluated. A total of 66 sets of four different image formats were independently interpreted by five observers. The analysis of the receiver operating characteristic curves suggested that the high-contrast film copies were superior to their original analog images and comparable with computer-processed images in diagnostic yield. It appears that contrast enhancement by simple film copying can improve the accuracy of 201Tl image interpretation

  17. 201Tl brain SPECT in differentiating central nervous system lymphoma from toxoplasmosis in AIDS patients

    International Nuclear Information System (INIS)

    In AIDS patients, toxoplasmosis and lymphoma are the leading causes of CNS mass lesions. It is important to make the correct diagnosis expeditiously, since the two diseases require markedly different treatments and have different prognoses. In general, CT and MR imaging have failed to provide specific distinguishing characteristics to differentiate CNS lymphoma from toxoplasmosis, and it is difficult to differentiate these entities clinically. We performed 201Tl brain SPECT in order to differentiate two diseases. Counts ratio of a lesion to the normal brain (L/N ratio) was elevated in patients of lymphoma compared in patients of toxoplasmosis. 201Tl brain SPECT is useful to differentiate CNS lymphoma from toxoplasmosis. (author)

  18. Different thallium-201 single-photon emission tomographic patterns in benign and aggressive meningiomas

    International Nuclear Information System (INIS)

    To evaluate the possibility of preoperatively obtaining an index of aggressiveness for intracranial meningiomas, we prospectively studied 22 patients with computed tomographic or magnetic resonance imaging evidence of meningeal tumour, using single-photon emission tomography (SPET) of the brain and thallium-201 (201Tl). On a brain-dedicated SPET scanner, a rapid acquisition protocol with early, short scans was started simultaneously with the intravenous administration of 111 MBq 201Tl, covering the initial intratumoral distribution of the tracer. Twenty minutes post injection, a delayed SPET scan was also obtained. On the reconstructed and attenuation-corrected images we calculated the 201Tl concentration in tumour and normal contralateral brain tissue, and compared intratumoral tracer concentration in the initial and the final part of the rapid acquisition protocol. Benign and malignant meningiomas were classified as such based on histological examination. In malignant lesions, the ratio of the 201Tl concentration at 2-4 min post injection to that at 14-16 min was found to be significantly higher than in non-aggressive neoplasms (mean±1 SD: 1.14±0.31 and 0.56±0.13, respectively, P 201Tl concentration values at 2-4 and at 14-16 min. Our findings suggest that the comparative assessment of intratumoral 201Tl concentration at 2-4 and at 14-16 min post injection could provide a fast, simple method to differentiate preoperatively intracranial meningiomas with different biological behaviour. (orig.). With 3 figs., 1 tabTo evaluate the possibility of preoperatively obtaining an index of aggressiveness for intracranial meningiomas, we prospectively studied 22 patients with computed tomographic or magnetic resonance imaging evidence of meningeal tumour, using single-photon emission tomography (SPET) of the brain and thallium-201 (201Tl). On a brain-dedicated SPET scanner, a rapid acquisition protocol with early, short scans was started simultaneously with the intravenous administration of 111 MBq 201Tl, covering the initial intratumoral distribution of the tracer. Twenty minutes post injection, a delayed SPET scan was also obtained. On the reconstructed and attenuation-corrected images we calculated the 201Tl concentration in tumour and normal contralateral brain tissue, and compared intratumoral tracer concentration in the initial and the final part of the rapid acquisition protocol. Benign and malignant meningiomas were classified as such based on histological examination. In malignant lesions, the ratio of the 201Tl concentration at 2-4 min post injection to that at 14-16 min was found to be significantly higher than in non-aggressive neoplasms (mean±1 SD: 1.14±0.31 and 0.56±0.13, respectively, P <0.01). Conversely, in the delayed scan, most lesions showed high tracer concentration, and the two groups could not be distinguished. In addition, three recurrent meningiomas displayed the same imaging behaviour as the malignant group, i.e. h

  19. Usefulness of rapid low-dose/high-dose 1-day 99mTc-sestamibi ECG-gated myocardial perfusion single-photon emission computed tomography

    International Nuclear Information System (INIS)

    The clinical usefulness of a rapid rest low-dose/stress high-dose (dose ratio=1:5) 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) protocol for the detection of coronary artery disease was evaluated. In 89 patients, rest images were obtained immediately after the injection of 99mTc-sestamibi (256.1±28.4 MBq) followed by drinking water (400 ml). Exercise or vasodilator stress test was performed immediately after the completion of rest imaging with the injection of 99mTc-sestamibi (1312.3±167.6 MBq). Prior to the post-stress imaging, patients were asked again to drink water (400 ml) in order to eliminate subdiaphragmatic tracer activity. The myocardial count ratio (stress/rest) of 99mTc-sestamibi was calculated. Image quality was scored using a 4-point scale system (4=excellent, 3=good, 2=poor, 1=unacceptable). Coronary angiography was performed in 56 patients within 1 month of the SPECT scan. All patients successfully performed the protocol and total examination time was 108±7 min. The myocardial count ratio of 99mTc-sestamibi was always greater than 6. The image quality was satisfactory both at rest (3.4±0.9) and after stress (3.9±0.2). The sensitivity and specificity to detect coronary artery stenosis >50% was 84% and 97%, respectively. This rapid one-day 99mTc-sestamibi protocol provides adequate image quality and diagnostic accuracy for detecting coronary artery disease. (author)

  20. False-positive defects in technetium-99m sestamibi myocardial single-photon emission tomography in healthy athletes with left ventricular hypertrophy

    International Nuclear Information System (INIS)

    Exercise ECG and myocardial single-photon emission tomography (SPET) are fundamental in the non-invasive evaluation of patients suspected of having coronary artery disease (CAD). The purpose of the present study was to investigate the influence of physiological left ventricular hypertrophy (LVH) on myocardial sestamibi SPET in healthy young and old athletes. Eighteen young male elite athletes (ten rowers, five power/weight lifters and three triathletes) and 14 well-trained elderly rowers were studied. All underwent a bicycle test as part of a 2-day sestamibi SPET protocol. Attenuation correction was not performed. The studies were evaluated visually and quantitatively analysed by the CEqual program with its reference files and with a file from a local non-athletic age-matched population. Echocardiographic LVH was an inclusion criterion in the young athletes. Exercise ECG was normal in all subjects. In at least three of the young athletes a reversible defect was observed by visual analysis. On quantitative analysis one-third of the young athletes had ''significant'' (>10 pixels) defects compared with both the local reference base and the CEqual reference population. Nearly all defects were found in the anterior or inferior wall. The remaining subjects, including all old rowers, had normal SPET findings. Anterior and inferior wall defects are so common in healthy athletes with physiological LVH that the specificity of myocardial SPET, in contrast to exercise ECG, seems to be too low for evaluation of chest pain in this group. The mechanism of anterior and inferior defects may be related to hot spots (papillary muscles?) in the lateral wall. The specificity of SPET is maintained in athletes without LVH. (orig.)

  1. Effect of eating on thallium myocardial imaging

    International Nuclear Information System (INIS)

    To determine if eating between initial and delayed thallium images alters the appearance of the delayed thallium scan, a prospective study was performed; 184 subjects sent for routine thallium imaging were randomized into two groups, those who ate a meal high in carbohydrates between initial and delayed thallium myocardial images (n = 106), and those who fasted (n = 78). The 201Tl images were interpreted in blinded fashion for global myocardial and pulmonary clearance of 201Tl myocardial defects. The eating group had a significantly lower incidence of transient myocardial defects compared to the noneating group (7 percent vs 18 percent, respectively; p less than 0.05). The time between initial and delayed images and the incidence of exercise-induced ischemic ST-segment depression or pathologic Q waves on the electrocardiogram were not significantly different between the two groups. These data suggest that eating a high-carbohydrate meal between initial and delayed 201Tl images causes increased 201Tl myocardial clearance rates and may alter 201Tl myocardial redistribution over time

  2. The role of 201Tl scintigraphy in evaluating proliferative activity in thyroid neoplasms

    International Nuclear Information System (INIS)

    To identify the relationship between the uptake of 201Tl and the proliferative activity in thyroid neoplasms, 201Tl scintigraphy was performed in 57 patients with thyroid neoplasms. 201Tl uptake ratio was calculated in both the early and the delayed images and then compared with factors representing cellular or practical proliferative activity of the lesions. The labeling index (LI) for proliferating cell nuclear antigen (PCNA) was determined quantitatively by flow cytometry. There was a significant correlation between the uptake ratio and LI for PCNA. The correlation coefficient for the delayed ratio (DR) vs. LI was better than that for the early ratio (ER) vs. LI. As parameters for practical proliferation, the surgical stage in primary thyroid carcinoma or 131I uptake in recurrent thyroid carcinoma was focused on. DR was strongly related to these parameters, regardless of the histopathological features or size of the lesions. Our results suggest that 201Tl uptake in delayed thyroid scan is useful in assessing proliferative activity in thyroid neoplasms. (author)

  3. Segmental analysis of 201-Tl emission computerized tomography of the heart. Evaluation by coronarographic data

    International Nuclear Information System (INIS)

    Segmental analysis of SPECT 201-Tl stress study of the heart is a very sensitive and specific method highly predictive for coronary arteriosclerotic disease in the studied population. Distinction between single and multivessel disease was possible in 75% of the cases. In comparison with planar scintigraphy anomalies of the infero-posterior wall are better visualized

  4. Evaluation of 201Tl-DDC as a cerebral blood flow tracer

    International Nuclear Information System (INIS)

    We studied rCBF in 28 patients (cerebrovascular disease, epilepsy, migraine, dementia) by means of 201Tl-DDC (Diethyldithiocarbamate) and SPECT and, for comparison, all patients underwent also a control SPECT study with IMP or HMPAO. DDC-SPECT images are comparable to SPECT images using IMP or HMPAO. In addition, DDC seems to offer some advantages. (orig./MG)

  5. Significance of exercise-induced ST segment depression in patients with myocardial infarction involving the left circumflex artery. Evaluation by exercise thallium-201 myocardial single photon emission computed tomography

    International Nuclear Information System (INIS)

    The significance of exercise-induced ST segment depression in patients with left circumflex artery involvement was investigated by comparing exercise electrocardiography with exercise thallium-201 single photon emission computed tomography (Tl-SPECT) and the wall motion estimated by left ventriculography. Tl-SPECT and exercise electrocardiography were simultaneously performed in 51 patients with left circumflex artery involvement (angina pectoris 30, myocardial infarction 21). In patients with myocardial infarction, exercise-induced ST depression was frequently found in the V2, V3 and V4 leads. In patients with angina pectoris, ST depression was frequently found in the II, III, aVF, V5 and V6 leads. There was no obvious difference in the leads of ST depression in patients with myocardial infarction with ischemia and without ischemia on Tl-SPECT images. In patients with myocardial infarction, the lateral wall motion of the infarcted area evaluated by left ventriculography was more significantly impaired in the patients with ST depression than without ST depression (p<0.01). Exercise-induced ST depression in the precordial leads possibly reflects wall motion abnormality rather than ischemia in the lateral infarcted myocardium. (author)

  6. Sex-specific criteria for interpretation of thallium-201 myocardial uptake and washout studies

    International Nuclear Information System (INIS)

    A study was undertaken to determine the effect of gender on criteria for the quantitative analysis of exercise-redistribution 201Tl myocardial scintigraphy. The studies of 26 normal females and 23 normal males were subjected to bilinear interpolative background subtraction and horizontal profile analysis. Significant sexual differences were found in both regional uptake ratios and washout rates. These differences primarily reflected a proportionately decreased anterior and upper septal uptake in females, and faster washout in females. Faster myocardial 201Tl washout rates in females could not be clearly ascribed to either a physiological or artifactual explanation. It is concluded that since important differences exist between males and females in the detected pattern of 201Tl myocardial uptake and washout, sex-specific criteria may enhance the predictive accuracy of exercise-redistribution 201Tl myocardial scintigraphy

  7. Thallium-201 myocardial SPECT findings at rest in sarcoidosis

    International Nuclear Information System (INIS)

    In 41 patients with sarcoidosis (diagnosed according to criteria recommended by the Committee on Diffuse Pulmonary Disease, Ministry of Health and Welfare, Japan 1988), thallium-201 (201Tl) myocardial SPECT was performed to investigate: the ability of 201Tl SPECT to detect cardiac involvement of sarcoidosis with images recorded at rest and 2 hours later, and the relationships between 201Tl myocardial SPECT findings and the activity of sarcoidosis or endomyocardial biopsy findings. As to the abnormal findings in 201Tl myocardial SPECT, a low density area was seen in 13 of 41 cases (31.7%) and non-uniform uptake was found in 17 cases (41.5%), the mean washout ratio (n=39) was 16.5±7.4%, which is significantly lower than that found in normal subjects, 23.9±7.5% (n=10). Of the 19 patients judged visually to be normal, 5 patients had a reduced mean washout ratio less than 12%. Thus, the incidence of abnormal findings including all types of abnormality in sarcoidosis was 63.4% (26/41 cases). As measured by the serum ACE (angiotensin converting enzyme) or lysozyme level, or the presence of more than 30% symphocyte fraction in BALF (broncho-alveolar lavage fluid), 20 (80%) of 25 cases with 201Tl abnormality were judged to be active sarcoidosis, while only 6 (37.5%) of 16 cases with normal findings on 201Tl SPECT were judged to be active. This suggest that there is a significant relationship between the presence or absence of an abnormal finding on 201Tl myocardial SPECT and the activity of sarcoidosis. Among 13 patients examined by endomyocardial biopsy, 10 patients had abnormal findings on 201Tl myocardial SPECT and 7 of these 10 patients had no histological evidence of cardiac sarcoidosis. In all of these 7 patients, however, sarcoidosis was judged to be active. This suggest that endomyocardial biopsy is of limited value in the diagnosis of cardiac sarcoidosis. (author)

  8. An experimental animal model of chronic myocardial hibernation: comparative study of cine-MR, myocardial single photon emission computed tomography and pathology

    International Nuclear Information System (INIS)

    Objective: To establish the chronic low-flow myocardial hibernation animal model in pigs, and to assess the diagnostic value for myocardial hibernation by using various imaging methods. Methods: A total of 13 miniswine (30-40 kg) were used. All animals underwent general anesthesia and orotracheal intubation while the animals were mechanically ventilated. Under sterile conditions, left ventriculography and coronary angiography were performed by introduction of catheter into the right femoral artery. Further, a left anterolateral thoracotomy was performed in the third intercostal space. The proximal LCX was dissected free to allow placement of an ameroid constrictor. More than 1 month later, left ventriculography and coronary angiography were performed again, followed by cine-MRI at rest and during stress with low-dose of dobutamine (5?g·kg-1·min-1), respectively. Traditional and/or breath-hold cine-MRI were used to evaluate regional left ventricular wall motion, corresponding to basal, midventricular and apical short-axis tomograms. Regional wall motion score index (WMSI) was calculated. At the same time 99mTc-MIBI myocardial SPECT was performed at rest and during nitroglycerin administration, respectively. All animals were finally sacrificed for pathological examination. Triphenyl tetrazolium chloride (TTC) staining was used to assess the myocardial infarction. Electron microscopy was used to identify myocardial cellular changes characteristic of hibernating myocardium. Results: Three pigs died during surgery or within two weeks after surgery. One pig died of anesthesia during SPECT examination, 1 pig suffered from aneurysm, and another one pig showed negative findings. The other 7 pigs were found with hypokinetic (n=4) or akinetic (n=3) myocardial regions related to stenosed LCX (70%-99%). Resting cine-MRI demonstrated decreased regional motion of the lateral and posteroinferior walls (ischemic regions) of the left ventricle (n=7), compared with the nonischemic anteroseptal regions; but the low dose dobutamine (5?g·kg-1·min-1) could recover those hypokinetic or akinetic myocardial regions, characteristic of hibernating myocardium. Resting 99mTc-MIBI myocardial SPECT (n=6) showed a fixed perfusion defect on the corresponding ischemic areas, which became reversible on the nitrate-augmented myocardial perfusion imaging. It also indicated myocardial viability presented at the ischemic areas. TTC staining revealed patchy infarction of the area-at-risk localized to the endocardial surface (n=3), and no myocardial infarction (n=4). Electron microscopy of sections from the hibernating regions revealed loss of contractile materials, increased numbers of small mitochondria, and glycogen accumulation within viable cardiomyocytes, which had been described as hallmarks of hibernating myocardium. Conclusion: Chronic low-flow myocardial hibernation can be reproduced in an animal model during progressive coronary stenosis caused by ameroid constrictor

  9. Thallium-201 single photon emission computed tomography imaging of meningioma cells in hyperostosis

    International Nuclear Information System (INIS)

    Hyperostosis is a well-known bony reaction associated with meningioma. However, it is difficult to determine preoperatively whether meningioma cells have invaded the bone, and if so, the extent of tumor invasion. Preoperative thallium-201 chloride single photon emission computed tomography (201Tl SPECT) was performed in four patients with meningioma and hyperostosis. The presence of meningioma cells in bone biopsy specimens was also investigated using standard histological techniques. 201Tl SPECT revealed increased uptake in three of the four patients. Biopsy specimens from these three patients revealed invasion of the bony lesions by meningioma cells in accordance with the 20lTl SPECT findings. 20lTl SPECT found no abnormal uptake in the other patient, in which there was also no histological evidence of tumor invasion of bone. Preoperative 20lTl SPECT can provide information on bone invasion by meningioma, which will facilitate preoperative planning of the extent of bony resection required at meningioma surgery. (author)

  10. Canine myocardial images by 201Thallium-Cl scintigraphy after coronary occlusion with and without reperfusion

    International Nuclear Information System (INIS)

    Ligation of the coronary artery was performed in 30 dogs. Twelve dogs underwent reperfusion, and in all dogs 201Tl scintigraphy was performed in addition to examination with sodium fluorescein and pathohistological studies. Uptake of 201Tl was seen to decrease with the period of ligation. In long term ligation, the range of the 201Tl defect in the canine heart was narrow and differentiation was difficult, but pathohistologically remarkable thinning of the ventricular wall was observed. In 3 dogs which received preligation administration of 201Tl and heart resection 15 minutes after ligation, fluorescent defects were observed in the occluded areas but there was no noticeable decrease in 201Tl. In all reperfused cases, regardless of the reperfusion time, the decrease of 201Tl uptake disappeared within 6 hours and no defects were observed on sodium fluorescein studies after reperfusion. In cases reperfused after 12 hours-6 days ligation, decrease in 201Tl uptake and irreversible pathohistological changes were observed. These results showed that 201Tl uptake accurately reflected circulatory and myocardial disturbance. (author)

  11. Incomplete redistribution in delayed thallium-201 single photon emission computed tomographic (SPECT) images: an overestimation of myocardial scarring

    International Nuclear Information System (INIS)

    To determine if incomplete redistribution at 4 h in exercise tomographic thallium-201 studies is always due to a myocardial scar, 141 patients were evaluated before and after a total of 160 successful percutaneous transluminal coronary angioplasty procedures. Thallium studies were analyzed using polar bull's-eye maps. For both immediate and delayed images, abnormalities were quantified as a thallium score by calculating a standard deviation-weighted sum of pixels greater than 2.5 SD below gender-matched normal limits. One hundred forty-four of 160 studies indicated abnormalities before angioplasty. Of these 144, incomplete redistribution occurred in 111 (77%): 16 (14%) in patients with and 95 (86%) in patients without prior Q wave myocardial infarction. After angioplasty, improvement in delayed image score occurred in 8 (50%) of 16 patients with prior infarction and 72 (76%) of 95 patients without prior infarction (p less than 0.05). After angioplasty, delayed images were normal in 1 (6%) of 16 patients with prior infarction and 32 (34%) of the 95 without (p less than 0.05). Before angioplasty, delayed image scores were positively correlated with scores in the immediate postexercise images in patients with (r = 0.84) and those without (r = 0.69) prior infarction. To determine if additional delayed images could help differentiate scar from ischemia, an 8 to 24 h delayed image was obtained in each of 40 other patients with incomplete redistribution at 4 h. Of 28 patients without prior infarction, 15 had no redistribution, and 13 had further redistribution at 8 to 24 h

  12. Iodine-123 N-methyl-4-iododexetimide: a new radioligand for single-photon emission tomographic imaging of myocardial muscarinic receptors

    International Nuclear Information System (INIS)

    Cardiac muscarinic receptor ligands suitable for positron emission tomography have previously been characterised. Attempts to develop radioligands of these receptors suitable for single-photon emission tomographic (SPET) imaging have not been successful due to high lung retention and high non-specific binding of previously investigated potential tracers. The purpose of this study was to evaluate the biodistribution and in vivo imaging characteristics of a new radiopharmaceutical, [123I]N-methyl-4-iododexetimide. Biodistribution studies performed in rats showed high cardiac uptake (2.4% ID/g) 10 min after injection with a heart to lung activity ratio of 5:1. Specificity and stereoselectivity of cardiac binding were demonstrated using blocking experiments in rats. Dynamic imaging studies in anaesthetised greyhounds demonstrated rapid and high myocardial uptake and low lung binding with stable heart to lung activity ratios of >2.5:1 between 10 and 30 min, making SPET imaging feasible. Administration of an excess of an unlabelled muscarinic antagonist, methyl-quinuclidinyl benzylate rapidly displaced myocardial activity to background levels and the pharmacologically inactive enantiomer, [123I]N-methyl-4-iodolevetimide, had no detectable cardiac uptake, indicating specific and stereoselective muscarinic receptor binding. SPET revealed higher activity in the inferior than in the anterior wall, this being consistent with previously described regional variation of cardiac parasympathetic innervation. [123I]N-methyl-4-iododexetimide shows promise as an imaging agent for muscarinic receptor distribution in the heart and may be helpful in evaluating diverse cardiac diseases associated with altered muscarinic receptor function, including heart failure and diabetic heart disease. (orig.)

  13. Myocardial infarction determined by technetium-99m pyrophosphate single-photon tomography complicating elective coronary artery bypass grafting for angina pectoris

    International Nuclear Information System (INIS)

    The incidence of acute myocardial infarction (AMI) complicating coronary artery bypass grafting (CABG) has previously been based on concordance of electrocardiographic, enzymatic and scintigraphic criteria. Technetium-99m pyrophosphate (Tc-PPi) single-photon emission computed tomography now enables detection of AMI with high sensitivity and specificity. Using this technique, perioperative AMI was detected in 12 of 58 patients (21%) undergoing successful elective CABG for stable angina pectoris. Stepwise multivariate logistic regression analysis was performed to compare the predictive value of preoperative (New York Heart Association class, left ventricular ejection fraction and use of beta blockers) and intraoperative (number of grafts constructed, use of internal mammary anastomoses, use of sequential saphenous vein grafts, smallest grafted distal vessel lumen caliber and aortic cross-clamp time) variables. Preoperative New York Association class (p = 0.04) and smallest grafted distal vessel lumen caliber (p = 0.03) were significant multivariate predictors of perioperative AMI. Only 1 perioperative patient with AMI (and 1 pyrophosphate-negative patient) developed new Q waves. Serum creatine kinase-MB was higher in patients with AMI by repeated measures analysis of variance (p = 0.0003). Five AMIs occurred in myocardial segments revascularized using sequential saphenous vein grafts, and 7 in segments perfused by significantly stenosed epicardial vessels with distal lumen diameter and perfusion territory considered too small to warrant CABG. At 6-month follow-up, the mean left ventricular ejection fraction increased from 0.61 to 0.65 in Tc-PPI-negative patients (p = 0.01), but not in perioperative patients with AMI

  14. Medium- to long-term prognostic impact of dipyridamole thallium-201 myocardial single-photon emission computed tomography in elderly patients

    International Nuclear Information System (INIS)

    Dipyridamole thallium-201 single-photon emission computed tomography (SPECT) has not been extensively evaluated for risk stratification and the medium- to long-term prognostic value in elderly cardiac patients who are unable to exercise. The present study group comprised 210 consecutive patients aged at least 70 years with known or suspected coronary artery disease (CAD). The SPECT findings were classified as a reversible, fixed, or combined (reversible and fixed) defect. Of the 210 patients, 201 (77±5 years, 85 male) were successfully followed for 49±26 months. Thirteen (7%) patients had cardiac events: cardiac death (n=10), non-fatal myocardial infarction (n=1), or coronary artery bypass grafting (n=2). Cardiac events occurred in 3 of 112 patients with normal SPECT and in 10 of 89 patients with an abnormal scan (0.7%/year vs 2.8%/year, p=0.01). Stepwise Cox regression analysis revealed that the significant predictors of cardiac events were combined defects (relative risk 7.3) and the number of defect areas (relative risk 4.4). The predictive value of dipyridamole thallium-201 SPECT is maintained over 4 years in mixed populations of elderly CAD patients who are unable to exercise. (author)

  15. Effect of thallium-201 blood levels on reversible myocardial defects

    International Nuclear Information System (INIS)

    To determine if 201Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise 201Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H2O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H2O and 210 min after eating/H2O. Between initial and immediate post eating/H2O images 201Tl reversible defects occurred in 27/38 regions in the H2O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma 201Tl activity was significantly higher in the H2O test than eating test (p less than 0.05). In conclusion, early reversal of 201Tl defects may, in part, be the result of higher plasma 201Tl activity early after initial postexercise 201Tl imaging

  16. Correlation of myocardial perfusion single photon emission computed tomography with coronary artery calcium score in coronary artery disease- An Indian perspective

    International Nuclear Information System (INIS)

    Full text: Objectives: The consequences of atherosclerosis can be detected by coronary artery calcium score (CACS) and stress induced myocardial ischemia on myocardial perfusion single photon emission computed tomography (MPS). We assessed the relationship between stress induced myocardial ischemia on (MPS) and magnitude of CACS by 64 slice computed tomography (CT) in patients undergoing both tests. Methods: Our study included 59 patients with no earlier history of coronary artery disease (CAD) of both sexes (males-47, females-12) in age group of 34-69 years. Our patients were referred by cardiologists after they underwent CACS. Of these 37 patients (63%) presented with symptoms which included chest pain (non-anginal, anginal, atypical) presence or absence of shortness of breath, and rest (37%) were asymptomatic. For each patient coronary risk factors were noted. All these patients underwent CACS and rest and stress MPS one-day protocol with Tc99m sestamibi within 7 days. According to CACS and symptoms, patients were divided into four groups, group A - asymptomatic 100 n=13, group D - symptomatic >100 (n=11). The incidence of inducible ischemia in MPS was compared to the magnitude of CACS abnormality. Results: There were 21 patients (36%) with ischemic MPS. According to groups, group A - 11%(n=1), groupB- 38%(n=10), groupC- 30%(n=4) and group D- 54%(n=6) had ischemic MPS. From the above we observed that incidence of ischemic MPS is more with increasing CACS. And also it is noted that it is more frequent in patients who presented with symptoms irrespective of CACS who are at short-term risk. In negative MPS, CACS may be useful in long term risk stratification in finding out subclinical atherosclerosis. Conclusion: The general perception is that the CACS is a good tool for long-term risk stratification but it may be applicable to those patients with no significant risk factors. When there are risk factors MPS is a better indicator for risk stratification for CAD irrespective of CACS. Further studies incorporating prognostic follow- up are required. (author)

  17. Initial multicentre experience of high-speed myocardial perfusion imaging: comparison between high-speed and conventional single-photon emission computed tomography with angiographic validation

    International Nuclear Information System (INIS)

    High-speed (HS) single-photon emission computed tomography (SPECT) with a recently developed solid-state camera shows comparable myocardial perfusion abnormalities to those seen in conventional SPECT. We aimed to compare HS and conventional SPECT images from multiple centres with coronary angiographic findings. The study included 50 patients who had sequential conventional SPECT and HS SPECT myocardial perfusion studies and coronary angiography within 3 months. Stress and rest perfusion images were visually analysed and scored semiquantitatively using a 17-segment model by two experienced blinded readers. Global and coronary territorial summed stress scores (SSS) and summed rest scores (SRS) were calculated. Global SSS ?3 or coronary territorial SSS ?2 was considered abnormal. In addition the total perfusion deficit (TPD) was automatically derived. TPD >5 % and coronary territorial TPD ?3 % were defined as abnormal. Coronary angiograms were analysed for site and severity of coronary stenosis; ?50 % was considered significant. Of the 50 patients, 13 (26 %) had no stenosis, 22 (44 %) had single-vessel disease, 6 (12 %) had double-vessel disease and 9 (18 %) had triple-vessel disease. There was a good linear correlation between the visual global SSS and SRS (Spearman's ? 0.897 and 0.866, respectively; p < 0.001). In relation to coronary angiography, the sensitivities, specificities and accuracies of HS SPECT and conventional SPECT by visual assessment were 92 % (35/38), 83 % (10/12) and 90 % (45/50) vs. 84 % (32/38), 50 % (6/12) and 76 % (38/50), respectively (p < 0.001). The sensitivities, specificities and accuracies of HS SPECT and conventional SPECT in relation to automated TPD assessment were 89 % (31/35), 57 % (8/14) and 80 % (39/49) vs. 86 % (31/36), 77 % (10/13) and 84 % (41/49), respectively. HS SPECT allows fast acquisition of myocardial perfusion images that correlate well with angiographic findings with overall accuracy by visual assessment better than conventional SPECT. Further assessment in a larger patient population may be needed to confirm this observation. (orig.)

  18. Myocardial perfusion assessed by contrast echocardiography and single photon emission computed tomography in the evaluation of patients with acute chest pain and normal electrocardiogram

    International Nuclear Information System (INIS)

    Aim : Evaluation of diagnostic accuracy of myocardial contrast echocardiography (MCE) in comparison with single-photon emission computed tomography (SPECT) for the detection of myocardial ischemia in patients with acute chest pain. Material and Methods : Eighteen patients (pts) with chest pain lasting ?30 minutes, occurring within 6 hours of emergency room presentation and a normal or no diagnostic electrocardiogram were studied. Pts underwent rest MCE and SPECT. For both exams myocardial perfusion was assessed in the same 7 segments (apical, anterior, inferior, anteroseptal, inferoseptal, lateral and posterior) of left ventricle. A total of 126 segments were analyzed. Images were classified as positive for ischemia if they had a perfusion defect. Coronary angiography was performed if MCE or SPECT images were classified as positive for ischemia or by clinical indication. Otherwise the patients underwent stress SPECT. Significant coronary artery disease (CAD) was defined as ?70% stenosis in a major coronary artery or its branches. Final diagnosis of an acute coronary event (ACE) was established in the presence of positive findings in MCE or SPECT in addition to significant CAD in the corresponding territory. Kappa statistics were calculated to evaluate the concordance between MCE and SPECT. ? values of ?0.4, >0.4 and >0.7 indicate fair, good and excellent agreement, respectively. Results: Thirteen out of 18 pts underwent coronary angiography (seven pts had positive findings on SPECT, 2 on MCE, 2 on both exams and 1 had clinical indication). Significant CAD was detected on six. Five pts underwent stress SPECT and no perfusion defect was detected. Therefore, six pts (33.3%) had an ACE and 12 (66.6%) had not. There were no statistical differences between groups according to age, gender, duration of pain, free pain interval, presence of risk factors and antecedents. Concordance between MCE and SPECT for evaluation of perfusion defects showed a ? coefficient of 0.04. Sensitivity, specificity, negative and positive predictive values for SPECT were, respectively, 100%, 75%, 100% and 60%. For MCE these values were, respectively, 20%, 76%, 71.4% and 50%. Conclusion: SPECT demonstrated to be a reliable technique in the discrimination of patients with an ACE among those who were admitted with acute chest pain at emergency room. MCE was less useful in this setting

  19. Initial multicentre experience of high-speed myocardial perfusion imaging: comparison between high-speed and conventional single-photon emission computed tomography with angiographic validation

    Energy Technology Data Exchange (ETDEWEB)

    Neill, Johanne [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); The Prince Charles Hospital, Brisbane (Australia); Prvulovich, Elizabeth M.; Bomanji, Jamshed B. [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); Fish, Matthews B. [Sacred Heart Medical Center (SHMC), Springfield, OR (United States); Berman, Daniel S.; Slomka, Piotr J. [Cedars-Sinai Medical Center, Los Angeles, CA (United States); Sharir, Tali [Procardia Maccabi Healthcare Services (PMHS), Tel Aviv (Israel); Martin, William H. [Vanderbilt University Medical Center (VUMC), Nashville, TN (United States); DiCarli, Marcelo F. [Brigham and Women' s Hospital (BWH), Boston, MA (United States); Ziffer, Jack A. [Baptist Hospital of Miami (BHM), Miami, FL (United States); Shiti, Dalia [Spectrum-Dynamics, Caesarea (Israel); Ben-Haim, Simona [University College London Hospital, Institute of Nuclear Medicine, London (United Kingdom); Chaim Sheba Medical Center, Department of Nuclear Medicine, Tel-Hashomer (Israel)

    2013-07-15

    High-speed (HS) single-photon emission computed tomography (SPECT) with a recently developed solid-state camera shows comparable myocardial perfusion abnormalities to those seen in conventional SPECT. We aimed to compare HS and conventional SPECT images from multiple centres with coronary angiographic findings. The study included 50 patients who had sequential conventional SPECT and HS SPECT myocardial perfusion studies and coronary angiography within 3 months. Stress and rest perfusion images were visually analysed and scored semiquantitatively using a 17-segment model by two experienced blinded readers. Global and coronary territorial summed stress scores (SSS) and summed rest scores (SRS) were calculated. Global SSS {>=}3 or coronary territorial SSS {>=}2 was considered abnormal. In addition the total perfusion deficit (TPD) was automatically derived. TPD >5 % and coronary territorial TPD {>=}3 % were defined as abnormal. Coronary angiograms were analysed for site and severity of coronary stenosis; {>=}50 % was considered significant. Of the 50 patients, 13 (26 %) had no stenosis, 22 (44 %) had single-vessel disease, 6 (12 %) had double-vessel disease and 9 (18 %) had triple-vessel disease. There was a good linear correlation between the visual global SSS and SRS (Spearman's {rho} 0.897 and 0.866, respectively; p < 0.001). In relation to coronary angiography, the sensitivities, specificities and accuracies of HS SPECT and conventional SPECT by visual assessment were 92 % (35/38), 83 % (10/12) and 90 % (45/50) vs. 84 % (32/38), 50 % (6/12) and 76 % (38/50), respectively (p < 0.001). The sensitivities, specificities and accuracies of HS SPECT and conventional SPECT in relation to automated TPD assessment were 89 % (31/35), 57 % (8/14) and 80 % (39/49) vs. 86 % (31/36), 77 % (10/13) and 84 % (41/49), respectively. HS SPECT allows fast acquisition of myocardial perfusion images that correlate well with angiographic findings with overall accuracy by visual assessment better than conventional SPECT. Further assessment in a larger patient population may be needed to confirm this observation. (orig.)

  20. Quantitative evaluation of myocardial single-photon emission tomographic imaging: application to the measurement of perfusion defect size and severity

    International Nuclear Information System (INIS)

    A new method is described for precise quantitative analysis of the relative three-dimensional distribution of myocardial tracers. The system uses a 360 elliptical sampling of radial slices to create activity profiles. These are then positioned onto a common centre at the same angular coordinates as the corresponding radial slice reconstruction planes to generate a two-dimensional polar summary display. Abnormal distribution is then identified by automatic comparison of the patient polar map with the threshold of a normal database defined on a pixel by pixel basis as the normal mean -2.5 SD. Our stress and rest databases currently comprise 34 and 24 studies for sestamibi and tetrofosmin respectively. The present method differs from currently available software in two major respects. Calculation of defect extent takes into account the surface distortion resulting from planar projection by using pixel by pixel weighted factors but it is otherwise overestimated as a result of the limited resolution of the imaging system. Integrating defect severity and extent, our hypoperfusion index appeared to accurately estimate the true defect size in our phantom model (r=0.993). The reproducibility of analysis was 6.24% in phantom studies and 3.10% in patient studies including repeated acquisitions. Applied to a well-documented population of 80 patients, this method resulted in an 86% sensitivity and a 78% specificity for overall coronary artery disease detection with reference to thery disease detection with reference to the angiographic data. (orig.). With 14 figs., 2 tabsA new method is described for precise quantitative analysis of the relative three-dimensional distribution of myocardial tracers. The system uses a 360 elliptical sampling of radial slices to create activity profiles. These are then positioned onto a common centre at the same angular coordinates as the corresponding radial slice reconstruction planes to generate a two-dimensional polar summary display. Abnormal distribution is then identified by automatic comparison of the patient polar map with the threshold of a normal database defined on a pixel by pixel basis as the normal mean -2.5 SD. Our stress and rest databases currently comprise 34 and 24 studies for sestamibi and tetrofosmin respectively. The present method differs from currently available software in two major respects. Calculation of defect extent takes into account the surface distortion resulting from planar projection by using pixel by pixel weighted factors but it is otherwise overestimated as a result of the limited resolution of the imaging system. Integrating defect severity and extent, our hypoperfusion index appeared to accurately estimate the true defect size in our phantom model (r=0.993). The reproducibility of analysis was 6.24% in phantom studies and 3.10% in patient studies including repeated acquisitions. Applied to a well-documented population of 80 patients, this method resulted in an 86% sensitivity and a 78% specificity for overall coronary artery disease detection with reference to t

  1. Classification of 201TL and sup(99m)Tc-pertechnetate leg scan patterns and evaluation of their clinical significance

    International Nuclear Information System (INIS)

    Classification of the 201Tl and sup(99m)Tc-pertechnetate (sup(99m)TcOsub(4-)) leg scan patterns and their clinical significance were evaluated in the patients with ischemic diseases of the lower extremities (IDL) Five patterns were distinguished in both 201Tl and sup(99m)TcOsub(4-) leg scans; A: decreased activity throughout the affected leg, B: localized decreased activity in the affected leg, C: localized decreased activity associated with increased activity in the affected leg, D: generalized of localized increased activity in the affected leg and E: no laterality of the activity. 201Tl and sup(99m)TcOsub(4-) leg scan patterns were agreed in 55% of the patients. 201Tl leg scan had tendency to correlate the level of the vascular lesion in pattern B and C,However, diagnosis of the level of the lesion was difficult from the leg scan. Pattern D of the 201Tl leg scan was associated with increased blood flow in the affected leg on radionuclide angiography in 42% of the patients. After surgery, sup(99m)TcOsub(4-) leg scan tended to show pattern D, especially in the patients with lumbar sympathectomy. Patterns A, B and C were thought to suggest the ischemia. Patterns C and D were thought to express reactive hyperemia induced by the ischemic lesion. In the 60 preoperative IDL, sensitivity of 201Tl leg scan alone was 76% and that of combined use of 201Tl and sup(99m)TcOsub(4-) leg scans was 85%. Addition of radionuclide angiography increased sensitivity of IDL upto 98% and accuracy was 98%. Combined use of 201Tl and sup(99m)TcOsub(4-) leg scans and radionuclide angiography was useful for detection of IDL, and was also useful for evaluation of the results of the surgical intervention. (J.P.N.)

  2. Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates

    International Nuclear Information System (INIS)

    Gated single-photon emission computed tomography (SPECT) imaging of myocardium by 99mTc and 201Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by 99mTc-labelled tracers than in 201Tl. Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. (orig.)

  3. Dosimetry of four heart-imaging radionuclides: 43K, 81Rb, 129Cs, and 201Tl

    International Nuclear Information System (INIS)

    In conjunction with research into the relative clinical suitability of radionuclides for heart imaging, estimates of the radiation dose from 43K, 81Rb, 129Cs, and 201Tl were calculated. Estimates of absorbed radiation dose for the heart, kidneys, liver, lungs, testes, and whole body of the standard man were computed from published distribution data in rats via the MIRD method by assuming that the concentration in each organ per initial mean whole-body concentration is the same in rats and humans. The whole-body absorbed radiation doses from 81Rb, 129Cs, 201Tl, and 43K are 0.08, 0.17, 0.24, and 0.60 rads/mCi administered intravenously. In general, the organ doses for the four radionuclides follow the same order

  4. Usefulness of 99mTc-methoxy-iso-butyl-isonitrile myocardial single photon emission computed tomography during infusion of low-dose dobutamine and nitroglycerin. Evaluation of myocardial viability

    International Nuclear Information System (INIS)

    This study evaluated myocardial viability with 99mTc-methoxy-iso-butyl-isonitrile (MIBI) single photon emission computed tomography (SPECT) during infusion of low-dose of dobutamine (DOB) and nitroglycerin (NTG). The subjects were 13 patients with coronary artery disease associated with wall motion abnormalities. Myocardial SPECT with MIBI was performed during infusion of NTG followed by infusion of DOB. Rest MIBI study was also performed on a separate day. The regional uptake of MIBI was visually evaluated by scoring (from 0=normal to 3=defect) in 9 regions of left ventricular wall in comparison with LVG or echocardiography data. The regional uptake of MIBI was quantitatively evaluated in 33 segments of left ventricular wall by a computer. The uptake of MIBI during infusion of both DOB and NTG was compared with that at rest study in the region of wall motion abnormalities. The mean uptake score of MIBI during infusion of both DOB and NTG and that of MIBI at rest was 1.8 and 2.1, respectively. The uptake of MIBI was significantly improved by infusion of both DOB and NTG (p<0.01). Percent of the peak activity of MIBI during infusion of both DOB and NTG and that of MIBI at rest in the region where the uptake score had been improved was 76.6±12.7% versus 74.0±13.1% (p<0.01). Percent of the peak activity of MIBI in the region where the uptake score had not been improved was 60.1±18.1% versus 60.7±18.7% (NS). Quantitative study also showed a significant improvement of MIBI uptake on the study of DOB and NTG. These results suggest that MIBI SPECT during infusion of both DOB and NTG infusion might be useful for evaluating myocardial viability. (S.Y.)

  5. Therapeutic effects of coenzyme Q10 on dilated cardiomyopathy. Assessment by 123I-BMIPP myocardial single photon emission computed tomography (SPECT). A multicenter trial in Osaka University Medical School Group

    International Nuclear Information System (INIS)

    To evaluate therapeutic effects of Coenzyme Q10 (CoQ10), 15 patients with dilated cardiomyopathy were investigated by 123I-BMIPP myocardial single photon emission computed tomography (SPECT). The BMIPP defect score was determined semiquantitatively by using representative short and long axial SPECT images. Mean BMIPP defect score with CoQ10 treatment was significantly low, 7.7±6.1 compared to 12.7±7.4 without CoQ10 treatment. On the other hand, in 8 patients of dilated cardiomyopathy, % fractional shortening using echocardiography was not different before and after CoQ10 treatment. In conclusion, 123I-BMIPP myocardial SPECT was proved to be sensitive to evaluate the therapeutic effects of CoQ10, which improve myocardial mitochondrial function, in the cases of dilated cardiomyopathy. (author)

  6. Superconducting Single Photon Detectors:

    OpenAIRE

    Dorenbos, S. N.

    2011-01-01

    This thesis is about the development of a detector for single photons, particles of light. New techniques are being developed that require high performance single photon detection, such as quantum cryptography, single molecule detection, optical radar, ballistic imaging, circuit testing and fluorescence spectroscopy. Superconducting single photon detectors (SSPDs) are sensitive to single photons from the ultraviolet to the near infrared. In this thesis steps has been taken towards improvi...

  7. The value of gallium-67 and thallium-201 whole-body and single-photon emission tomography images in dialysis-related {beta}{sub 2}-microglobulin amyloid

    Energy Technology Data Exchange (ETDEWEB)

    Yen Tzuchen; Tzen Kaiyuan [Dept. of Nuclear Medicine, Chang Gung Memorial Hospital, Taipei Medical Center and School of Medicine, Chang Gung University (Taiwan); Chen Kuosu; Tsai Chijuen [Dept. of Nephrology, Chang Gung Memorial Hospital at Keelung (Taiwan)

    2000-01-01

    The aim of this study was to investigate the value of gallium-67 and thallium-201 whole-body and single-photon emission tomography (SPET) images in long-term dialysis patients in whom dialysis-related {beta}{sub 2}-microglobulin amyloid ({beta}{sub 2}-MA) was clinically suspected. Twenty-three patients who had received dialysis for at least 10 years were included in the study. A technetium-99m methylene diphosphonate (MDP) whole-body scan was performed in all of the patients. If there was any MDP accumulation in the articular and/or peri-articular region, {sup 67}Ga and {sup 201}Tl whole-body and SPET images were then acquired. If any {sup 67}Ga and/or {sup 201}Tl uptake was observed, a CT-guided biopsy was done. In those patients who had articular and/or peri-articular uptake of {sup 99m}Tc MDP, {sup 67}Ga and/or {sup 201}Tl and who were pathologically proven to have {beta}{sub 2}-MA, {sup 99m}Tc MDP, {sup 67}Ga and {sup 201}Tl whole-body scans and SPET were carried out again, both 3 months and 1 year after initiation of treatment. This served to evaluate the therapeutic effect and allowed comparison with the clinical findings. Of the 23 patients, eight had abnormal {sup 99m}Tc MDP uptake. Among these eight, six had intense {sup 99m}Tc MDP, {sup 67}Ga and {sup 201}Tl uptake in the articular and peri-articular regions before medication. Three months after the start of treatment, there were very marked decreases in uptake on both the {sup 67}Ga and {sup 201}Tl scans but less obvious changes in uptake of {sup 99m}Tc-MDP. In comparison with the other clinical manifestations such as limitation in range of motion, the more the painful disability improved, the less was the uptake on both {sup 67}Ga and {sup 201}Tl scans. There were virtually no differences in uptake pattern between the three scans of each radiopharmaceutical obtained for each patient in both 3 months and 1 year after initial of treatment. It is concluded that {sup 99m}Tc-MDP whole-body bone scan can both detect active and pre-existing inactive deposits of {beta}{sub 2}-MA. {sup 67}Ga and {sup 201}Tl scans are helpful to differentiate active from inactive deposits of {beta}{sub 2}-MA and to evaluate the therapeutic effect on these patients. SPET images are usually needed to distinguish articular and peri-articular lesions from bone lesions. (orig.)

  8. The value of gallium-67 and thallium-201 whole-body and single-photon emission tomography images in dialysis-related ?2-microglobulin amyloid

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the value of gallium-67 and thallium-201 whole-body and single-photon emission tomography (SPET) images in long-term dialysis patients in whom dialysis-related ?2-microglobulin amyloid (?2-MA) was clinically suspected. Twenty-three patients who had received dialysis for at least 10 years were included in the study. A technetium-99m methylene diphosphonate (MDP) whole-body scan was performed in all of the patients. If there was any MDP accumulation in the articular and/or peri-articular region, 67Ga and 201Tl whole-body and SPET images were then acquired. If any 67Ga and/or 201Tl uptake was observed, a CT-guided biopsy was done. In those patients who had articular and/or peri-articular uptake of 99mTc MDP, 67Ga and/or 201Tl and who were pathologically proven to have ?2-MA, 99mTc MDP, 67Ga and 201Tl whole-body scans and SPET were carried out again, both 3 months and 1 year after initiation of treatment. This served to evaluate the therapeutic effect and allowed comparison with the clinical findings. Of the 23 patients, eight had abnormal 99mTc MDP uptake. Among these eight, six had intense 99mTc MDP, 67Ga and 201Tl uptake in the articular and peri-articular regions before medication. Three months after the start of treatment, there were very marked decreases in uptake on both the 67Ga and 201Tl scans but less obvious changes in uptake of 99mTc-MDP. In comparison with the other clinical manifestations such as limitation in range of motion, the more the painful disability improved, the less was the uptake on both 67Ga and 201Tl scans. There were virtually no differences in uptake pattern between the three scans of each radiopharmaceutical obtained for each patient in both 3 months and 1 year after initial of treatment. It is concluded that 99mTc-MDP whole-body bone scan can both detect active and pre-existing inactive deposits of ?2-MA. 67Ga and 201Tl scans are helpful to differentiate active from inactive deposits of ?2-MA and to evaluate the therapeutic effect on these patients. SPET images are usually needed to distinguish articular and peri-articular lesions from bone lesions. (orig.)

  9. Evaluation of 201TlCl per rectum scintigraphy in biliary atresia

    International Nuclear Information System (INIS)

    To study whether or not 201TlCl per rectum scintigraphy is clinically useful for evaluating portosystemic shunt in biliary atresia (BA), we reviewed 13 patients with biliary atresia already in the postoperative state. The patients' details were as follows: age, 4 years 6 months-18 years 7 months (mean: 12 years 7 months); male, 3 cases; females, 10 cases; type III BA, 11 cases; type I-cyst BA, 2 cases. A radioisotope (RI) of 201TlCl (18.5 or 37.0 MBq) was administered via the rectum. Heart and liver counts per area were calculated respectively 30-60 minutes after RI administration, and the ratio of heart and liver (H/L ratio) was adopted as a indicator of portosystemic shunt. There was no correlation between the H/L ratio and laboratory examinations (total bilirubin, alanine aminotransferase, cholinesterase, white blood cell and platelet). There was positive correlation between the H/L ratio and splenomegaly. Splenomegaly was evaluated using gray-scale ultrasonography. There was a positive correlation between the H/L ratio and existence of esophageal varices. Esophageal varices were evaluated using barium meal upper gastrointestinal examination. There was a remarkable positive correlation between the H/L ratio and the patient's age. This group of patients was restricted to that in which the laboratory liver function test was abnormal. The use of 201TlCl via rectum scintigraphy and quantitatively conducted H/L ratio are clinically useful for evaluating the portosystemic shunt in biliary atresia. The portosystemic shunt might gradually increase with patients' age independently of the liver function, which should support our daily clinical observations. (author)

  10. [Myocardial tissue vitality: clinical relevance, pathophysiology and identification].

    Science.gov (United States)

    Bax, J J; Cornel, J H; Poldermans, D; van Eck-Smit, B L; van der Wall, E E

    1998-01-10

    Heart failure is an increasing clinical problem because of the rising frequency of admissions and the high mortality. Excellent long-term results are obtained with heart transplantation, whereas the long-term prognosis is poor when patients are treated medically. It has recently been demonstrated that, in patients with depressed left ventricular (LV) function, revascularization may be an alternative form of therapy, since improvement of LV function, which is an important prognostic factor, may occur after coronary revascularization. Recovery of LV function after revascularization may occur in patients with dysfunctional but viable myocardium, whereas no recovery can be expected in patients with scar tissue. Improvement of LV function after revascularization can be explained on the basis of the concept of myocardial tissue vitality': chronically ischaemic myocardium temporarily loses the facility to contract, but the contraction is regained after revascularization (once the ischaemia is eliminated). For the selection of patients who may profit by a revascularization procedure, techniques have been developed for the identification of dysfunctional but viable tissue. The myocardial glucose metabolism can be visualized by administration of 18F desoxyglucose (FDG) and imaging by positron emission tomography or 'single photon emission computer tomography'. Vital tissue shows diminished perfusion with intact glucose metabolism (FDG perfusion mismatch); a vital tissue shows diminished perfusion without glucose metabolism (FDG perfusion match). Scintigraphy of the membrane of the myocardial cell can also be investigated using 201Tl scintigraphy. Reserve contractility of the myocardium can be visualized by echocardiography during administration of dobutamine. PMID:9556996

  11. Accuracy of preoperative pinhole subtraction single photon emission computed tomography for patients with primary and recurrent hyperparathyroidism in an endemic goiter area

    International Nuclear Information System (INIS)

    Bilateral parathyroid exploration is still the standard therapeutic procedure for primary and recurrent hyperparathyroidism (HPTH). Since a unilateral surgical strategy that reduces surgical complications should not increase the risk of missing enlarged parathyroid glands, reliable preoperative imaging is the first requirement for this approach. This study was conducted to assess the accuracy of preoperative 99mTcO4-201Tl pinhole subtraction single photon emission computed tomography (SPECT) compared with sonography. The study population consisted of 15 patients with primary (n=13) or recurrent (n=2) HPTH who underwent preoperative 99mTcO4-201Tl pinhole subtraction SPECT. Preoperative sonography was also done in 14 of these patients. 99mTcO4-201Tl pinhole subtraction SPECT was significantly more accurate than sonography. It had an overall accuracy of 80% in detection of enlarged parathyroid glands. The accuracy of localization increased to 92.3% in patients with solitary adenomas, and to 100% in those with solitary adenomas and no previous parathyroid exploration. The high accuracy of preoperative localization with 99mTcO4-201Tl pinhole subtraction SPECT in patients with primary and recurrent HPTH allows for an imaging-guided unilateral operative strategy in most patients, even those with concomitant nodular goiters. This may reduce the risk of surgical complications and expand the use of minimally invasive techniques in parathyroid surgery. (author)

  12. Detection of myocardial viability by means of Single Proton Emission Computed Tomography (Perfused SPECT) dual 201 Tl (rest of 15 minutes, 24 late hours and 24 hours reinjection) and gated-SPECT 99m Tc-SESTAMIBI in effort or stimulation of the coronary reserves

    International Nuclear Information System (INIS)

    The objective of this work was to determine if the images of SPECT 201 TI in rest of 15 minutes, 24 late hours and Gated-SPECT 99m Tc-SESTAMIBI in effort or stimulation of coronary reservation correlate with the study of 24 hours post reinjection of 201TI to determine the presence of having knitted viable myocardium. Material and methods: 29 patients were studied with coronary arterial illness (EAC) to who are carried out SPECT 201 TI in rest with images of 15 minutes, 24 late hours and 24 hours reinjection, by means of the administration of 201TI to dose of 130 MBq and reinjection with 37 MBq. and Gated-SPECT 99mTc-SESTAMIBI in effort or stimulation of coronary reservation, later to the administration of 1110 MBq. Results: 29 patients were included according to inclusion approaches and exclusion, of those which 22 (75.86%) they correspond at the masculine sex and 7 (24.13%) to the feminine one, with an average of 62.1 year-old age, 2320 segments myocardial were analysed so much it is phase post-effort as rest; they were diagnosed a total of 264 segments with heart attack, of which viability myocardium was observed in 174 segments. The statistical tests are analysis of frequencies. The non parametric test of Wilcoxon and Mann-Whitney. Conclusions: the viability myocardial at the 24 late hours and 24 hours reinjection was similar; significant difference exists between the study of 15 minutes and 24 hours reinjection, ischemic illness was also demonstrated in territories different to the heart attack area in the studies of 15 minutes, late 24 hours and 24 hours reinjection. (Author)

  13. Comparison of the myocardial uptake of a technetium-labeled isonitrile analogue and thallium

    International Nuclear Information System (INIS)

    The myocardial transmicrovascular transport of thallium-201 (201Tl) and technetium-99m hexakis(2-methoxyisobutylisonitrile) (MIBI) were compared during variable blood flow levels in nine blood-perfused, isolated rabbit hearts. Seventeen injections of radiolabeled albumin and EDTA as well as 201Tl and MIBI were performed by indicator-dilution techniques. When coronary flow was varied from 0.52 to 3.19 ml/g/min, myocardial extraction for MIBI averaged 0.38 +/- 0.09 (SD) whereas 201Tl myocardial extraction averaged 0.73 +/- 0.10 (p less than 0.001). Net extraction, which was calculated using end points of 1.8-4.9 minutes, averaged 0.41 +/- 0.15 for MIBI and was less than the 201Tl net extraction of 0.57 +/- 0.13 (p less than 0.001). The mean capillary permeability-surface area product for MIBI (0.44 +/- 0.13 ml/g/min) was one third of 201Tl (1.30 +/- 0.45 ml/g/min; p less than 0.001). However, parenchymal cell permeability-surface area product for MIBI (47.58 +/- 25.85 ml/g/min) was much higher than 201Tl (6.52 +/- 6.51 ml/g/min; p less than 0.0001), and apparent cellular volume of distribution for MIBI (15.15 +/- 3.31 ml/g) was also higher than 201Tl (10.19 +/- 4.00 ml/g; p less than 0.01). These data suggest that capillary permeability for 201Tl is greater than MIBI, but the reverse is true at the parenchymal cell wall. In addition, a new blood-perfused preparation is used for indicator-dilution techniques, and previously developed modeling analyses are also extended to these experiments

  14. Computer simulation of temperature distribution on a solid target for 201Tl production

    International Nuclear Information System (INIS)

    Thallium-201 is of great interest in nuclear medicine for diagnostic purposes. It is produced by the 203Tl(p,3n)201Pb nuclear reaction. Since the target for 201Tl production is a solid target and the maximum beam current for the irradiation has a direct relation with its temperature surface, therefore, the control of temperature during the irradiation is essential. Designing a proper cooling system is one of the important and determining parameters in radionuclide production efficiency. Non-controlled temperature would cause melting and consequently loss of target materials that could be very costly especially when an isotopically enriched material is used. In this study, the heat transfer and temperature distribution on the target has been simulated based on a computational fluid dynamics (CDF) code for the thermal behavior of the target during the irradiation and under the different beam currents, cooling flow rates and target designing. The results on the routinely used target for the production of 201Tl in AMIRS, showed that there was a good linearity between proton beam currents (in the range of 100-350 ?A) and maximum temperature on the thallium target (345-458 K). The results also showed that the flow rate of the cooling water can be brought down (from routinely used 45 L/min) to 15 L/min without any risk of melting of target material. (authors)

  15. Serial changes in myocardial perfusion and function after successful percutaneous transluminal coronary angioplasty, examined by stress thallium-201 myocardial scintigraphic and stress radionuclide ventriculographic studies

    International Nuclear Information System (INIS)

    In order to study the early and late effects of percutaneous transluminal coronary angioplasty (PTCA), 201Tl myocardial perfusion scintigraphy and exercise 99mTc ventriculography were performed in 25 patients who successfully received PTCA. Before PTCA, reduced myocardial perfusion on stress 201Tl image was observed in all 25 patients, while abnormal regional wall motion during exercise was seen in 22 cases. On stress 201Tl images, reduced myocardial perfusion was demonstrated in 11 cases at 3-7 days after PTCA, but in none at 3 months after the procedure. On the other hand, abnormal exercise regional wall motion was not observed in any case after successful PTCA even in the early phase. When the patients were divided into two groups according to the presence or absence of perfusion abnormalities on stress 201Tl images in the early post-PTCA phase, no difference was seen in clinical and coronary angiographic findings, exercise tolerance, 201Tl uptake score, wall motion score or left ventricular ejection fraction before the procedure. Thus, abnormal myocardial perfusion without impairment of regional left ventricular wall motion is frequently seen in the early post-PTCA phase. But this finding does not necessarily indicate associated myocardial ischemia. (author)

  16. Relationship between 123I-BMIPP imaging and cardiac function in acute myocardial infarction

    International Nuclear Information System (INIS)

    We evaluated the relationship between free fatty acid metabolism using 123I beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and cardiac function in acute myocardial infarction. Twenty-five patients were examined with 123I-BMIPP and 201Tl dual SPECT. The 123I-BMIPP images were compared with the 201Tl images and the left ventricular wall motions. The 123I-BMIPP images showed a larger uptake defect than the 201Tl images. This was marked in the patients after revascularization therapy. The uptake decrease of 123I-BMIPP was in good agreement with the decrease in regional wall motion. The incidence of accordance was 79% of the wall segments. The correlation between 123I-BMIPP defect size and ejection fraction was higher (r=-0.54) than that of 201Tl (r=-0.44). Subtraction of ejection fractions four weeks and soon after infarction correlated well with the subtraction of 123I-BMIPP and 201Tl defect sizes (r=0.55). In conclusion, 123I-BMIPP is more closely related to wall motion than 201Tl and might be valuable in predicting the functional improvement of acute myocardial infarction. (author)

  17. Utilidad de la tomografía computarizada de emisión de fotón único sincronizada con el electrocardiograma para la detección de isquemia miocárdica silente en diabéticos tipo 2 / Gated single photon emission computer tomography for the detection of silent myocardial ischemia

    Scientific Electronic Library Online (English)

    Yamilé, Peña Q; Marco Antonio, Coca P; Juan Felipe, Batista C; José, Fernández-Britto R; Rodobaldo, Quesada P; Andria, Peña C.

    2009-08-01

    Full Text Available [...] Abstract in english Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT) for the screening of silent myocardial ischemia in type 2 diabetic patients. Materi [...] al and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. AH subjects were also subjected to a coronary angiography whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specifity accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873). Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia.

  18. Utilidad de la tomografía computarizada de emisión de fotón único sincronizada con el electrocardiograma para la detección de isquemia miocárdica silente en diabéticos tipo 2 Gated single photon emission computer tomography for the detection of silent myocardial ischemia

    Directory of Open Access Journals (Sweden)

    Yamilé Peña Q

    2009-08-01

    Full Text Available Background: Asymptomatic patients with severe coronary atherosclerosis may have a normal resting electrocardiogram and stress test. Aim: To assess the yield of Gated Single Photon Emission Computer Tomography (SPECT for the screening of silent myocardial ischemia in type 2 diabetic patients. Material and methods: Electrocardiogram, stress test and gated-SPECT were performed on 102 type 2 diabetic patients aged 60 ± 8 years without cardiovascular symptoms. AH subjects were also subjected to a coronary angiography whose results were used as gold standard. Results: Gated-SPECT showed myocardial ischemia on 26.5% of studied patients. The sensibility, specifity accuracy, positive predictive value and negative predictive value were 92.3%, 96%, 95%, 88.8%, 97.3%, respectively. In four and six patients ischemia was detected on resting electrocardiogram and stress test, respectively. Eighty percent of patients with doubtful resting electrocardiogram results and 70% with a doubtful stress test had a silent myocardial ischemia detected by gated-SPECT There was a good agreement between the results of gated-SPECT and coronary angiography (k =0.873. Conclusions: Gated-SPECT was an useful tool for the screening of silent myocardial ischemia.

  19. Evaluation of myocardial viability using sequential dual-isotope single photon emission tomography imaging with rest Tl-201/stress Tc-99m tetrofosmin in the prediction of wall motion recovery after revascularization

    International Nuclear Information System (INIS)

    In patients with coronary artery disease (CAD), differentiation between severely ischemic but potentially viable myocardium and irreversibly infarcted tissue is clinically important, particularly when revascularization procedures are considered. Although thallium (Tl) cardiac imaging has been shown to be a good tool for investigating myocardial viability in CAD, this tracer shows physical limitations, such as a low photon energy and long half-life. We assessed the results of a rest Tl-201/stress Tc-99m tetrofosmin protocol in subjects with prior anterior myocardial infarction. All of the patients had an akinetic or dyskinetic area and more than 75% stenosis in the left anterior descending artery. All of the patients underwent revascularization after the examination. We evaluated the improvement in wall motion after revascularization using the centerline method with contrast left ventricular angiography. Fourteen patients showed reversible defects with the rest Tl-201/stress Tc-99m tetrofosmin protocol or in additional Tl-201 24 h redistribution images. All 14 patients showed a significant improvement in wall motion after revascularization. Dual-isotope rest Tl-201/stress Tc-99m tetrofosmin single photon emission tomography data, acquired separately, may give fast and complete information about myocardial perfusion during stress and at rest, and on about myocardial viability. (author)

  20. Feasibility of simultaneous dual-isotope myocardial perfusion acquisition using a lower dose of sestamibi

    International Nuclear Information System (INIS)

    The feasibility of simultaneous dual-isotope myocardial perfusion imaging was assessed using a ca. 12 mCi dose of technetium-99m sestamibi (MIBI) and ca. 3 mCi thallium-201. Planar and single-photon emission tomographic (SPET) data from 40 patients (41 studies) imaged with both a single- and a dual-isotope protocol were analyzed. Rest injected 201Tl (pure-Tl) images were acquired using 20% windows at 70 and 166 keV about 15 min after the 201Tl injection. Patients were then stressed, and at peak stress 99mTc-sestamibi was injected. About 30 min later 99mTc data were recorded with a 20% window center at 140 keV, and simultaneous 201Tl (dual-Tl) data were recorded with a single 20% window centered at 80 keV. Total myocardial counts based on SPET data in the dual-T1 images were increased by 18.61%±2.91% (SEM) (range: -12.8% to 84.1%) compared to pure-Tl images. Region of interest analysis revealed the greater increase in counts in the apical region and the least in the lateral wall. Pure Tl and dual-Tl images were visually evaluated for image quality (IQ) on a five-point scale (0=uncacceptable to 4=excellent). Dual-Tl IQ was lower than that of pure-Tl in 61% of cases, and similar in 37% (12% of the pure-Tl and 41% of the dual-Tl images fell into the 0 and 1 categories). Thallium perfusion abnormalities were of similar extent in 70% of segments, less severe in 18%, and more severe in 12%. There was an inverse correlation with patient weight, such that patients weighing more than 180 lbs had substantially worse images than those below this cutoff value. While dual-tracer images are of lower quality, they are interpretable if the patient is not severely overweight. (orig.)

  1. Absorbed radiation to the nuclear medicine nurses from patients administered 201Tl and 99mTc- MIBI

    International Nuclear Information System (INIS)

    People who have administrated radiopharmaceuticals could be a source of radiation to their relatives, medical nurses, and people who have contact them. In this study, the dose rates at various distances of 5, 10,50 and 100cm from 70 patients, who were administered diagnostic amounts of 201Tl-Chloride and 99mTc-MIBI, was measured using an ionization chamber. For determination of external radiation dose to the nurses the radiations in three deferent interval times have measured. The maximum values of external dose rates of 201Tl and 99mTc- MIBI were 11.2?Sv/h ±2.3 and 43.1?Sv/h ±11.9 respectively at 5cm from the patients. Significant exposure from patients after injection of 99mTc-MIBI was limited on the day of administration. Departure doses rate of 201Tl fell gradually so by 3 days after administration was significant. Maximum and average absorbed dose of nuclear medicine staff for one 201Tl scan was 4.6 and 2.7?Sv/h, and for 99mTc-MIBI was 18.1 and 9.8?Sv/h in a working day. (author)

  2. Absorbed radiation to the nuclear medicine nurses from patients administered 201Tl and 99mTc- MIBI

    International Nuclear Information System (INIS)

    People who have administrated radiopharmaceuticals could be a source of radiation to their relatives, medical nurses, and people who have contact them. In this study, the dose rates at various distances of 5, 10,50 and 100 cm from 70 patients, who were administered diagnostic amounts of 201Tl -Chloride and 99mTc -MIBI, was measured using an ionization chamber. For determination of external radiation dose to the nurses the radiations in three deferent interval times have measured. The maximum values of external dose rates of 201Tl and 99mTc-MIBI were 11.2?Sv/h ±2.3 and 43.1?Sv/h ±11.9 respectively at 5 cm from the patients. Significant exposure from patients after injection of 99mTc -MIBI was limited on the day of administration. Departure doses rate of 201Tl fell gradually so by 3 days after administration was significant. Maximum and average absorbed dose of nuclear medicine staff for one 201Tl scan was 4.6 and 2.7?Sv/h, and for 99mTc-MIBI was 18.1 and 9.8?Sv/h in a working day. (author)

  3. A new classification of lung cancer from a nucleomedical viewpoint using quantitative 201Tl and 67Ga scans in relation to histological type

    International Nuclear Information System (INIS)

    The possibility of nucleomedically classifying lung cancer was studied with quantitative 201Tl and 67Ga scans. Fundamental experiments with phantoms were performed to correct 201Tl and 67Ga uptake by tumors, and a clinical study based on these experiments was carried out on 31 patients with lung cancer. The classification of lung cancer was impossible by measuring either 201Tl uptake or 67Ga uptake alone, but was possible by calculating the Crude Uptake Ratio (CUR), the ratio of 201Tl uptake to 67Ga uptake by tumors on the same patients. Fifteen adenocarcinomas had a high CUR of 1.45 +- 0.77, many of them taking up more 201Tl than 67Ga. Nine epidermoid carcinomas had a CUR of 0.34 +- 0.25, significantly lower than adenocarcinomas (p67Ga than 201Tl. Two adenosquamous carcinomas had a CUR of 0.95 +- 0.19, intermediate between adenocarcinomas and epidermoid carcinomas. CURs varied greatly ranging from 0.03 to 4.31 and the 31 patients showed a continuous arrangement from low-CUR epidermoid carcinoma to high-CUR adenocarcinoma. The measurement of 201Tl and 67Ga uptake by the tumors was found to enable not only the nucleomedical classification but the presumption of various histogeneses in lung cancer. (author)

  4. Pathophysiology of technetium-99m stannous pyrophosphate and thallium-201 scintigraphy of acute anterior myocardial infarcts in dogs

    International Nuclear Information System (INIS)

    In 17 dogs with acute myocardial infarcts produced by ligation of the proximal left anterior descending coronary artery, a comparative study was made of myocardial scintigrams obtained with technetium-99m stannous pyrophosphate (/sup 99m/Tc-PYP) and thallium-201 (201Tl), tissue levels of /sup 99m/Tc-PYP and 201Tl uptake, histopathologic alterations, and regional myocardial perfusion measured with radioactive microspheres. Nine of the 10 hearts examined histologically had transmural infarcts with outer peripheral, inner peripheral, and central zones characterized by distinctive histopathologic features. A progressive reduction in myocardial blood flow was demonstrated between normal myocardium and the centers of the infarcts, and correlated well with progressive reduction in 201Tl uptake in the same regions. Marked /sup 99m/Tc-PYP concentration occurred in areas with partial to homogeneous myocardial necrosis and residual perfusion located in the outer peripheral regions of the infarcts. The latter areas also were characterized by the presence of muscle cell calcification. The patterns of distribution of /sup 99m/Tc-PYP and 201Tl explained the filling defects on 201Tl myocardial scintigrams and the doughnut patterns on /sup 99m/Tc-PYP myocardial scintigrams in dogs with transmural infarcts. One dog with a subendocardial infarct had a small homogeneous area of activity on the /sup 99m/Tc-PYP myocardial scintigram; and showed marked uptake of /sup 99m/Tc-PYP in subendocardial areas of extensive necrosis and calcification still receiving some coronary perfusion. Thus, the data indicate that the status of regional myocardial perfusion is a key determinant for the occurrence of distinctive patterns of myocardial necrosis and for the scintigraphic detection of acute myocardial infarcts with /sup 99m/Tc-PYP and 201Tl

  5. Single photon quantum cryptography

    OpenAIRE

    Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, Andre; Poizat, Jean-Philippe; Grangier, Philippe

    2002-01-01

    We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 9500 bits/s. The overall performances of our system reaches a domain where single photons have a measurab...

  6. Clinical significance of stress-induced ST segment changes in patients with previous myocardial infarction

    International Nuclear Information System (INIS)

    To explain the clinical significance of stress(st)-induced ST-segment (ST) changes postinfarction, 93 patients with previous myocardial infarction (MI) were performed st-201Tl myocardial single photon emission computed tomography (SPECT) and compared ST changes with SPECT, coronary arteriographic and left ventriculographic findings. 30 out of 93 cases (32%) had ST depression, 20 (21.5%) had ST elevation, 9 (10%) had both ST depression and elevation and remaining 34 (36.5 %) had no significant ST changes. In single vessel disease, ST depression were noted in 29% (12/42), while in multivessel disease, 53% (27/51). 35 out of 39 cases (90%) with ST depression had transient perfusion defect but no apparent relation was noted between location of ST depression on ECG and region of transient perfusion defect in SPECT. All of 28 cases with ST elevation were noted in anterior MI cases, and 26 out of these showed severe LV wall motion abnormality in contrast left ventriculography and broad anterior permanent defect in SPECT. Only 15 cases (54%) showed slight redistribution. Thus, we conclude that in patients with previous MI, st-induced ST depression seems to reflect myocardial ischemia and ST elevation possibly related abnormal LV wall motion. (author)

  7. Clinical study on myocardial imaging with ?-methyl-p-(123I)-iodophenyl-pentadecanoic acid in patients with mitochondrial myopathy

    International Nuclear Information System (INIS)

    Myocardial imaging with ?-methyl-p-(123I)-iodophenyl-pentadecanoic acid (123I-BMIPP), a new radiopharmaceutical designed to evaluate myocardial fatty acid metabolism, was performed in 7 patients with mitochondrial myopathy to detect their myocardial damages in comparison with 201Tl myocardial imaging. These patients were divided into 4 chronic progressive external ophthalmoplegia (CPEO) cases, 2 mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) cases and 1 myoclonus epilepsy with ragged-red fibers (MERRF). In visual assessment, we observed more myocardial segments with decreased uptake of 123I-BMIPP compared to 201Tl in MELAS cases than in CPEO cases. The mean myocardial uptake of 123I-BMIPP was higher than that of 201Tl in CPEO cases. On the other hand, in MELAS and MERRF cases, the mean myocardial uptake of 123I-BMIPP was lower than that of 201Tl. Abnormal findings suggesting myocardial damages were observed in echocardiogram and/or in electrocardiogram in MELAS and MERRF cases, while no such abnormal findings were observed in CPEO cases. Along with the previously reported experimental result that the impairment of rat myocardial mitochondria decreased myocardial uptake of 123I-BMIPP, these results suggest that 123I-BMIPP may be useful to detect myocardial damages in patients with mitochondrial myopathy. (author)

  8. Evaluation of myocardial perfusion by scanner and by gamma camera with computer ES 1020

    International Nuclear Information System (INIS)

    The regional myocardial perfusion was studied in 660 patients with myocardial infraction, stenocardia and myocardio-sclerosis. 408 patients were examined by scanner with 131Cs chloride, 95 patients with 201Tl chloride and 78 ones by gamma radiation camera and scanner with 201Tl chloride. Scanning with both radiocolloids reveals directly perfusion disturbances of a large and moderate size. The gamma radiation camera with computer reveals perfusion disturbances of a small and micro size which cannot be detected by the scanner. This technique is more precise and gives a more detailed information concerning the localization, degree and size of the perfusion disturbances. It is suggested that examination of myocardial perfusion by gamma radiation camera with computer using radiocolloid 201Tl chloride gives the best results and should be preferred

  9. Single photon emission computerized tomography

    International Nuclear Information System (INIS)

    In this thesis two single-photon emission tomographic techniques are presented: (a) longitudinal tomography with a rotating slanting-hole collimator, and (b) transversal tomography with a rotating gamma camera. These methods overcome the disadvantages of conventional scintigraphy. Both detection systems and the image construction methods are explained and comparisons with conventional scintigraphy are drawn. One chapter is dedicated to the determination of system parameters like spatial resolution, contrast, detector uniformity, and size of the object, by phantom studies. In separate chapters the results are presented of detection of tumors and metastases in the liver and the liver hilus; skeletal diseases; various pathological aberrations of the brain; and myocardial perfusion. The possible use of these two ect's for other organs and body areas is discussed in the last chapter. (Auth.)

  10. Myocardial uptake of thallium and rubidium during alterations in perfusion and oxygenation in isolated rabbit hearts

    International Nuclear Information System (INIS)

    The comparative effects of altered cellular function and coronary perfusion on myocardial 201Tl and 83Rb uptake were evaluated in three groups of isolated rabbit hearts having isovolumic contractions. Paired-indication dilution experiments were performed with 201Tl, 83Rb, and 111In-labeled albumin as an intravascular reference marker. In Group A hearts (n = 12), isotope transport was determined during control, hypoxia, and ischemia. In Group B hearts (n = 8), isotope transport was measured at control flow and again at a 50% and 80% reduction. In Group C hearts (n = 8) only 201Tl uptake was determined at control and following coronary reperfusion. Myocardial 201Tl and 83Rb transport were not significantly different and were proportional to flow. Although all interventions caused significant hemodynamic alterations, neither tracer was affected by hypoxia at constant flow. Thallium-201 permeation, however, was transiently decreased immediately after coronary reperfusion. We conclude that myocardial uptake of 201Tl and 83Rb are similar and directly related to flow, but do not reflect hypoxia induced cellular dysfunction

  11. Prediction of Changes in Left Ventricular Ejection Fraction after Off-Pump Coronary Artery Bypass Grafting Surgery by Myocardial Perfusion Single-Photon Emission Computed Tomography

    Directory of Open Access Journals (Sweden)

    Maryam Mirzaie

    2015-09-01

    Full Text Available Introduction: Left ventricular ejection fraction (LVEF is considered to be the single most important prognostic factor in patients with previous myocardial infarction. LVEF is not improved in all patients after coronary artery bypass grafting (CABG. This study aimed to assess the possibility of prediction of LVEF changes after CABG using myocardial perfusion gated signle photon emission computed tomography (GSPECT. Materials and Methods: Overall, 48 patients with mean LVEF of 30.2% (±4.7 underwent Echocardiography and GSPECT after injection of Tc-99m-MIBI at rest. Myocardial uptake was evaluated in 17 myocardial segments and was compared with age and gender matched normal data pool. The risks and benefits of CABG were explained to the patients and 16 cases (15 male and 1 female with the mean age of 61.1 years (±10.8 accepted to undergo off-pump CABG. All the patients were followed-up for at least six months and echocardiography and GSPECT were repeated at the end of follow up. Results: The mean LVEF was increased from of 31.1% (±3.5 to 34.5% (±3.6 after surgery (P

  12. Comparison between 360 and 180 data sampling in thallium-201 rest-redistribution single-photon emission tomography to predict functional recovery after revascularization

    International Nuclear Information System (INIS)

    The aim of this study was to perform a direct comparison between 180 and 360 data sampling in cardiac Tl-201 SPET to detect viable myocardium in patients undergoing revascularization; in order to allow optimal detection of viability a rest-redistribution protocol was used. The 201Tl results were compared with improvement of regional wall motion abnormalities after the revascularization, which was considered as the ''gold standard'' for myocardial viability. Thirty-two patients, scheduled for revascularization, underwent rest-redistribution 201Tl SPET, using a 360 arc. Raw data along a 180 arc (45 RAO to LPO) were selected from the original 360 data sets (both early an late 201Tl images). All SPET data were analysed semiquantitatively using circumferential profiles of the short-axis images; the data were displayed in polar maps. Criteria for viability included percentage 201Tl redistribution and percentage 201Tl activity on the late image. Regional wall motion was assessed with two-dimensional echocardiography before and 3 months after revascularization. The sensitivities of 360 and 180 imaging for the prediction of functional recovery were 82% and 89%, respectively, whereas the specificities were 51% and 55%, respectively. The diagnostic accuracy of 360 imaging was 62% and that of 180 imaging 67%. This study shows that 360 and 180 imaging have comparable diagnostic accuracy in the prediction of functional recovery after revascularization. With the newer dual-head gamma camera systems with each detector opposing each other, 360 imaging may be preferred. (orig./VHE). With 4 figs., 4 tabs

  13. Value of 201Tl imaging in predicting therapeutic 131I uptake in patients with thyroglobulin-positive but 131I scan-negative differentiated thyroid carcinoma

    International Nuclear Information System (INIS)

    Background: Serum thyroglobulin assay and 131Iodine (1311) whole body scan are considered complementary in detecting malignant thyroid tissue or metastases. A large number of patients, however, are encountered presenting with scan-negative, thyroglobulin-positive differentiated thyroid carcinoma posing a dilemma in therapeutic management. One of the first alternative scanning agents to be employed is 201Thallium (201Tl). Recent studies have demonstrated its usefulness in identifying lesions that are not visualized with traditional 131I whole body scan. It is not clear, however, whether 201Tl scan helps in the decision-making for subsequent 131I therapy. This study was conducted to determine if 201Tl scan can predict therapeutic 131I uptake and to define the clinical role of 201Tl scanning in these patients. Methods and results: A total of 12 patients (20-63 y/o), 5 males and 7 females, underwent surgery for differentiated thyroid cancer and all had serum thyroglobulin values above 10 ng/ml and normal TPO autoantibodies. Pre-therapy 131I scan using 111 MBq (3mCi) of 131I were obtained. As required for inclusion, all patients had negative pre-therapy scan and negative TPO autoantibody results and underwent 20lTl scanning within 3 weeks. All patients were given 131I therapy (3.7-5.5 GBq or 100-150 mCi) between one to two months after 201Tl scanning. Within a week after therapy, all patients underwent whole body 1311 scanning. 201Tl imaging demonstrated thyroid remnants in 9 out of 12 patients having positive 201Tl scan but negative pre-therapy 1311 scan. However, only 2 of the positive 201Tl scans showed 131I uptake post-therapy (positive predictive value of 20%). None of the subjects presented with a negative 201Tl scan and a positive post-therapy 131I scan. Conclusion: Our study suggests that evidence of remnants or metastases on 201Tl scanning may be an inappropriate basis for the decision to proceed with 131I therapy. The role of 20lTl imaging in this subset of patients may be limited to localization of metastases for surgical excision or localized radiation therapy. (authors)

  14. Effect of attenuation correction on myocardial thallium-201 distribution in patients with a low likelihood of coronary artery disease

    International Nuclear Information System (INIS)

    Regional variation of tracer distribution is seen in uncorrected thallium-201 images of normal hearts. This study evaluates the effect of attenuation correction on myocardial 201Tl distribution in patients with low risk of coronary artery disease. An L-shaped dual-detector single-photon emission tomographic system equipped with a pair gadolinium-153 scanning line sources was used for sequential emission/transmission imaging in 36 patients (14 men and 22 women) with less than 5% risk for coronary artery disease. Uncorrected emission images were reconstructed using filtered backprojection (FBP) whereas the attenuation corrected (AC) images were iteratively reconstructed using the attenuation map computed form the transmission data. Both sets of images were reorientated into short axis, vertical long axis and horizontal long axis images. For quantification data were reconstructed into polar plots and count density estimated in 17 myocardial segments. The population % standard deviation for each segment of AC data was significantly smaller than that for FBP data, indicating improved homogeneity of tracer distribution. In men the anterior-basal inferior activity ratio improved from 1.20 for FBP to 0.96 for AC (stress) and from 1.23 for FBP to 0.98 for AC (delay) (P201Tl distribution in patients with low risk of coronary artery disease. An L-shaped dual-detector single-photon emission tomographic system equipped with a pair gadolinium-153 scanning line sources was used for sequential emission/transmission imaging in 36 patients (14 men and 22 women) with less than 5% risk for coronary artery disease. Uncorrected emission images were reconstructed using filtered backprojection (FBP) whereas the attenuation corrected (AC) images were iteratively reconstructed using the attenuation map computed form the transmission data. Both sets of images were reorientated into short axis, vertical long axis and horizontal long axis images. For quantification data were reconstructed into polar plots and count density estimated in 17 myocardial segments. The population % standard deviation for each segment of AC data was significantly smaller than that for FBP data, indicating improved homogeneity of tracer distribution. In men the anterior-basal inferior activity ratio improved from 1.20 for FBP to 0.96 for AC (stress) and from 1.23 for FBP to 0.98 for AC (delay) (P<0.0001). In women the anterior-basal inferior activity ratio changed from 1.08 for FBP to 0.94 for AC (stress) and from 1.08 for FBP to 0.93 for AC (delay) (P<0.001). The apex of AC images showed a d

  15. Evaluation of coronary artery disease using myocardial thallium-201 imaging with single photon emission computed tomography during adenosine induced coronary vasodilation

    International Nuclear Information System (INIS)

    Adenosine-loaded Tl-201 myocardial SPECT was performed in consecutive 55 patients with suspected ischemic heart disease. Among these patients, 22 had cuncurrently exercise Tl-201 myocardial SPECT imaging for comparison. Adenosine was intravenously injected at a dose of 0.14 mg/kg/min continuously for 6 min, and 3 min after the stard of injection Tl-201 was injected via the different vein. Myocardial SPECT images were acquired at 5 min and 3 hr after the completion of intravenous injection of adenosine. Perfusion defect and the presence or absence of redistribution (RD) were visually interpreted from the short- and long-axial tomograms. Relative Tl-201 regional uptake ratios were quantitatively determined. Decreased systolic arterial pressure, increased heart rate, and slightly increased rate-pressure product were observed with adenosine injection. Chest pain (13 patients), head-ache (7), ST depression (17), and A-V block II were also seen; however, these symptoms rapidly disappeared with the withdrawal of adenosine. The findings by adenosine loading were concordent with those by exercise loading (91% for perfusion defect and 86% for presence or absence of RD). According to segments, both loading tests were concordent in 90% for persusion and 89% for RD. Both adenosine- and exercise-loaded imagings correlated well with regional Tl uptake by segements, the lowest value of Tl-201 defect, and extent score of Tl-201 defect. Adenosine-loaded imaging had a sensitivity of 100%, a specificity of 88%, and an accuracy of 97% for detecting parenchymal coronary lesions in evaluable 39 patients. In evaluable 22 patients, the sensitivity, specificity, and accuracy were 100%, 83%, and 95% for adenosine-loaded imaging and 88%, 83%, and 86% for exercise-loaded imaging. Thus, adenosine-loaded Tl-201 myocardial SPECT may be a safety and useful method for diagnosing ischemic heart disease. (N.K.)

  16. Single-photon sources

    International Nuclear Information System (INIS)

    The concept of the photon, central to Einstein's explanation of the photoelectric effect, is exactly 100 years old. Yet, while photons have been detected individually for more than 50 years, devices producing individual photons on demand have only appeared in the last few years. New concepts for single-photon sources, or 'photon guns', have originated from recent progress in the optical detection, characterization and manipulation of single quantum objects. Single emitters usually deliver photons one at a time. This so-called antibunching of emitted photons can arise from various mechanisms, but ensures that the probability of obtaining two or more photons at the same time remains negligible. We briefly recall basic concepts in quantum optics and discuss potential applications of single-photon states to optical processing of quantum information: cryptography, computing and communication. A photon gun's properties are significantly improved by coupling it to a resonant cavity mode, either in the Purcell or strong-coupling regimes. We briefly recall early production of single photons with atomic beams, and the operation principles of macroscopic parametric sources, which are used in an overwhelming majority of quantum-optical experiments. We then review the photophysical and spectroscopic properties and compare the advantages and weaknesses of various single nanometre-scale objects used as single-photon sources: atoms or ions in the gas phase and, in condensed matter, organic molecules, defect centres, semiconductor nanocrystals and heterostructures. As new generations of sources are developed, coupling to cavities and nano-fabrication techniques lead to improved characteristics, delivery rates and spectral ranges. Judging from the brisk pace of recent progress, we expect single photons to soon proceed from demonstrations to applications and to bring with them the first practical uses of quantum information

  17. Adsorption kinetics of 201Tl and migration of 99mTc in natural soils

    International Nuclear Information System (INIS)

    The safety is very important in facilities where radioactive wastes are stored. One of the necessary characteristics of the site where these wastes will be disposed is the soil permeability, since a waterproof terrain avoids the diffusion and radionuclide transport in the leakages case. The objective of this work is to study the adsorption kinetics of 201Tl and the migration of 99mTc in natural soil samples. The adsorption kinetics was determined starting from the obtaining of the retention coefficient of the thallium (static method) at different contact times. The technetium diffusion was studied by means of the dynamic method with different soil particles sizes. The results showed that the thallium is totally adsorbed starting from 20 h of contact among this and the mean. On the other hand, the technetium is very mobile in the soil, since it was possible to extract the majority of the tracer with little solvent. Also, it was found that for each soil gram the double water will be needed to leach the technetium almost in its entirety. Moreover, influence exists of the particle size in the migration velocity from the radiotracer to the most mobile being in major sizes than 2 mm that in minor size. (Author)

  18. Evaluation of bone and soft tissue lesion using 99mTc-MIBI. Comparison with 201Tl and the relation to chemotherapeutic effect

    International Nuclear Information System (INIS)

    Thirty-five patients with bone and soft tissue lesions were studied with 99mTc-MIBI and 201Tl to compare the uptake of two tracers. Planar images were obtained 15 min (early image) and 3 hr (delayed image) after the injection of both tracers. Images were evaluated visually and quantitatively using uptake ratio (lesion/background). In visual analysis, 23 of 35 patients showed similar uptake of both tracers, 9 showed more intense uptake of 99mTc-MIBI than 201Tl, and 3 showed more intense uptake of 201Tl than 99mTc-MIBI on early images. On delayed images, 21 of 32 patients showed similar uptake of both tracers, 3 showed more intense uptake of 99mTc-MIBI than 201Tl, and 8 showed more intense uptake of 201Tl than 99mTc-MIBI. In quantitative analysis, similar 201Tl and 99mTc-MIBI uptake ratios were obtained on early images. On delayed images, 99mTc-MIBI uptake ratios are less than that of 201Tl, but the difference was not significant. In some cases, 99mTc-MIBI accumulation was washed out on delayed images, therefore the early image is essential to evaluate 99mTc-MIBI accumulation. In all cases with the uptake ratios less than 1.20 on delayed 99mTc-MIBI images, chemotherapy was not effective. In malignant tumors, decreased uptake of 99mTc-MIBI accumulation on delayed images may inMIBI accumulation on delayed images may indicate that chemotherapy is not effective. Delayed 99mTc-MIBI image may be a potential marker predicting chemotherapeutic effect in malignant bone and soft tissue tumors. (author)Thirty-five patients with bone and soft tissue lesions were studied with 99mTc-MIBI and 201Tl to compare the uptake of two tracers. Planar images were obtained 15 min (early image) and 3 hr (delayed image) after the injection of both tracers. Images were evaluated visually and quantitatively using uptake ratio (lesion/background). In visual analysis, 23 of 35 patients showed similar uptake of both tracers, 9 showed more intense uptake of 99mTc-MIBI than 201Tl, and 3 showed more intense uptake of 201Tl than 99mTc-MIBI on early images. On delayed images, 21 of 32 patients showed similar uptake of both tracers, 3 showed more intense uptake of 99mTc-MIBI than 201Tl, and 8 showed more intense uptake of 201Tl than 99mTc-MIBI. In quantitative analysis, similar 201Tl and 99mTc-MIBI uptake ratios were obtained on early images. On delayed images, 99mTc-MIBI uptake ratios are less than that of 201Tl, but the difference was not significant. In some cases, 99mTc-MIBI accumulation was washed out on delayed images, therefore the early image is essential to evaluate 99mTc-MIBI accumulation. In all cases with the uptake ratios less than 1.20 on delayed 99mTc-MIBI images, chemotherapy was not effective. In malignant tumors, decreased uptake of 99mTc-MIBI accumulation on delayed images may i

  19. Evaluation of left ventricular function and volume in patients with dilated cardiomyopathy : gated myocardial single-photon emission tomography (SPECT versus echocardiography.

    Directory of Open Access Journals (Sweden)

    Berk Fatma

    2005-01-01

    Full Text Available Background: Left ventricular function, volumes and regional wall motion provide valuable diagnostic information and are of long-term prognostic importance in patients with dilated cardiomyopathy (DCM. This study was designed to compare the effectiveness of 2D-echocardiography and gated single-photon emission tomography (SPECT for evaluation of these parameters in patients with DCM. Patients and Methods: Gated SPECT and 2D-echocardiography were performed in 33 patients having DCM. Gated SPECT data, including left ventricular volumes and left ventricular ejection fraction (LVEF, were processed using an automated algorithm. Standard technique was used for 2D-echocardiography. Regional wall motion was evaluated using both modalities and was scored by two independent observers using a 16-segment model with a 5-point scoring system. Results: The overall agreement between the two imaging modalities for the assessment of regional wall motion was 56% (298/528 segments. With gated SPECT, LVEF, end-diastolic volume (EDV, and end-systolic volume (ESV were 27±9%, 217±77 mL, and 163±73 mL, respectively, and 30±8%, 195±58 mL, and 137±48 mL with echocardiography. The correlation between gated SPECT and 2D-echocardiography was good (r=0.76, P< 0.01 for the assessment of LVEF. The correlation for EDV and ESV were also good, but with wider limits of agreement (r=0.72, P< 0.01 and r=0.73, P< 0.01, respectively and significantly higher values were obtained with gated SPECT (P< 0.01. Conclusions: Gated SPECT and 2D-echocardiography correlate well for the assessment of LV function and LV volumes. Like 2D-echocardiography, gated SPECT provides reliable information about LV function and dimension with the additional advantage of perfusion data.

  20. Comparison of technetium-99m MIBI and thallium-201 chloride myocardial scintigraphy in infants

    International Nuclear Information System (INIS)

    Myocardial perfusion scintigraphy was performed with both 201Tl and a new six coordinate monocationic isonitrile complex of 99mTc, [99mTc]2-methoxyisobutylisonitrile (MIBI), on 11 infants who had undergone the arterial switch procedure for transposition of the great arteries. Unlike 201Tl which can show rapid and variable rates of washout from myocardium, 73% of the initial first-pass activity of the isonitrile complex in the myocardium remains 1 hr after intravenous administration. The images obtained with [99mTc]MIBI required a shorter recording time, entailed less radiation exposure to the patient, and were qualitatively at least as good as those obtained with 201Tl. No infant had perfusion abnormalities. The potential applications of the isonitrile complexes for myocardial perfusion scintigraphy in children are discussed

  1. Myocardial technetium-99m sestamibi single-photon emission tomography as a prognostic tool in coronary artery disease: multivariate analysis in a long-term prospective study

    International Nuclear Information System (INIS)

    A prospective study was started in 1988 and at present 176 consecutive, and thus unselected, patients have been enrolled. All of them have been submitted to stress-rest MIBI SPET for the diagnosis or evaluation of CAD; 147 patients (121 males and 26 females, aged 53±9 years) have completed a surveillance period of at least 36 months following the scintigraphic study (range 36-60 months, mean 43). Sixty-one patients had a documented previous myocardial infarction. The mean pre-test likelihood of CAD was 44% in the patients without prior infarction. The main anamnestic, clinical, EKG and scintigraphic findings were evaluated and statistically correlated with the incidence of ensuing cardiac events using both univariate (chi-square test) and multivariate analysis (logistic regression model). Twenty-nine patients suffered from a cardiac event during the follow-up period (i.e. three cardiac deaths, six myocardial infarctions and 20 cases of unstable angina). Statistical multivariate analysis identified MIBI scan as the only highly significant and independent prognostic predictor. In detail, the most important scintigraphic parameters were the presence of a reversible defect and the extension of the stress perfusion defect. The presence of typical angina proved to be a slightly significant predictor, while no other examined parameter showed a significant correlation with a bad prognosis. In conclusion, MIBI SPET can be considered a useful tool in the risk stratification of CAD patients. (orig.). With 3 tabs

  2. Cardiac functional mapping for thallium-201 myocardial perfusion, washout, wall motion and phase using single-photon emission computed tomography (SPECT)

    International Nuclear Information System (INIS)

    A method for three-dimensional functional mapping of Tl-201 myocardial uptake, washout, wall motion and phase was developed using SPECT. Each parameter was mapped using polar display in the same format. Normal values were determined in Tl-201 exercise study in 16 patients. Myocardial counts were lower in the septum and inferior wall and the difference of counts between anterior and inferior walls were greater in man compared with the perfusion pattern in woman. Washout was slower at septum and inferior wall in man, and slightly slower at inferior wall in woman. In gated blood-pool tomography, length-based and count-based Fourier analyses were applied to calculate the parameters of contraction and phase. The results of both Fourier analyses generally agreed; however, the area of abnormality was slightly different. Phase maps were useful for the assessment of asynergy as well as in patients with conduction disorders. These cardiac functional maps using SPECT were considered to be effective for the understanding of three-dimensional informations of cardiac function. (author)

  3. Single-photon Optomechanics

    CERN Document Server

    Nunnenkamp, A; Girvin, S M

    2011-01-01

    Optomechanics experiments are rapidly approaching the regime where the radiation pressure of a single photon displaces the mechanical oscillator by more than its zero-point uncertainty. We show that in this limit the power spectrum has multiple sidebands and that the cavity response has several resonances in the resolved-sideband limit. Using master-equation simulations, we also study the crossover from the weak-coupling many-photon to the single-photon strong-coupling regime. Finally, we find non-Gaussian steady-states of the mechanical oscillator when multi-photon transitions are resonant. Our study provides the tools to detect and take advantage of this novel regime of optomechanics.

  4. Indistinguishability of independent single photons

    OpenAIRE

    Sun, F. W.; Wong, C W

    2008-01-01

    The indistinguishability of independent single photons is presented by decomposing the single photon pulse into the mixed state of different transform limited pulses. The entanglement between single photons and outer environment or other photons induces the distribution of the center frequencies of those transform limited pulses and makes photons distinguishable. Only the single photons with the same transform limited form are indistinguishable. In details, the indistinguish...

  5. Therapeutic effect of co-enzyme Q10 on idiopathic dilated cardiomyopathy: assessment by iodine-123 labelled 15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid myocardial single-photon emission tomography

    International Nuclear Information System (INIS)

    It has been reported that myocardial mitochondrial function can be improved by the administration of co-enzyme Q10 (CoQ10). Recently, iodine-123 labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) was developed for metabolic imaging using single-photon emission tomography (SPET). This study was conducted to determine whether the therapeutic effects of CoQ10 on idiopathic dilated cardiomyopathy can be evaluated by BMIPP myocardial SPET. Fifteen patients, comprising 14 men and one woman (mean age: 64±12 years), were examined. CoQ10 was administered at 30 mg/day for a period of 35.7±12.4 days. BMIPP myocardial SPET was carried out before and after CoQ10 treatment. The count ratio of the heart (H) to the upper mediastinum (M) (H/M ratio) was calculated using a region of interest method with anterior planar imaging. Representative short-axis tomograms were divided into 27 segments (three slices x nine segments). Each segmental score was analysed semiquantitatively using a four-point scoring system (normal=0, mild low uptake=1, severe low uptake=2, defect=3). The H/M ratio showed a significant improvement, from 2.39±0.39 to 2.54±0.47, after treatment (P<0.05). The BMIPP total defect score after CoQ10 treatment was significantly decreased to 10.1±4.3, compared to 13.9±4.5 without CoQ10 treatment (P<0.001). However, the percent fractional shortening measured using echocardiography was not significantly different before and after CoQ treatment (19.2±8.1 vs 19.7±7.1). BMIPP myocardial SPET was confirmed to be sensitive in evaluating the therapeutic effects of CoQ10 in patients with idiopathic dilated cardiomyopathy. This method is unique, since the therapeutic effects can be estimated from the perspective of metabolic SPET imaging. (orig.). With 5 figs., 1 tab

  6. Analysis of heavy metals in [201Tl]TlCl injection using polarography

    International Nuclear Information System (INIS)

    Thallous-201 chloride produced at Korea Cancer Center Hospital(KCCH) is used in detecting cardiovascular disease and cancer. Thallium impurity can cause emesis, catharsis and nausea, so the presence of thallium and other metal impurities should be determined. According to USP and KP, their amounts must be less than 2 ppm in thallium and 5 ppm in total. In this study, the detection method of trace amounts of metal impurities in [201Tl]TlC1 injection with polarography was optimized without environmental contamination. For the detection of metal impurities, Osteryoung Square Wave Stripping Voltammetry method was used in Bio-Analytical System (BAS) 50W polarograph. The voltammetry was composed of Dropping Mercury Electrode (DME) as a working electrode, Ag/AgCl as a reference electrode and Pt wire as a counter electrode. Square wave stripping method, which makes use of formation and deformation of amalgam, was adopted to determine the metal impurities, and pH 7 phosphate buffer was used as supporting electrolyte. T1, Cu and Pb in thallous-201 chloride solution were detected by scanning from 300mV to -800mV. Calibration curves were made by using TINO3, CuSO4 and Pb(NO3)2 as standard solutions. T1 was confirmed at -450mV peak potential and Cu at -50mV. Less than 2 ppm of T1 and Cu was detected and Pb was not detected in KCCH-produced thallous-201 chloride injection. Detection limit of thallium and copper is approximately 50 ppb with this method. As a result of this experiment, thallium and other metal impurities in thallous-201 chloride injection, produced at Korea Cancer Center Hospital, are in the regulation of USP and KP. Polarograph could be applied for the determination of metal impurities in the quality control of radiopharmaceuticals conveniently without environmental contamination.=20

  7. Clinical studies on the thallium-201 myocardial scintiphotography in the patients with ischemic heart diseases

    International Nuclear Information System (INIS)

    Thallium-201 (201Tl) myocardial scintiphotography was performed in 34 patients with myocardial infarction and 13 with angina pectoris. Changing pattern of 201Tl activity in various organs observed. Myocardial blood flow was calculated from the relation of these activities. The body surface radioactivity of 201Tl decreased rapidly in initial phase, it gradually slowed down then reached to plateau on the heart and the lungs, while it increased gradually on the liver and kidneys. In patients with congestive heart failure, blood clearance of 201Tl was delayed and radioactivity on the lung area was increased compared with normal case. MBF/CO (%) ratio was calculated by the following way. Soon after the injection of 201Tl, serial images including whole chest were taken one frame in each one second during 30 seconds. Total injected dose was calculated from the maximum radioactivity in the frame. Myocardial uptake was calculated by the anterior view subtracting the mediastinal activity as the background at 5 minutes after the injection. MBF/CO (%) ratio was calculated as the myocardial uptake divided by the activity of total injected dose. Its mean value were 3.49 +- 0.45% in normals, 2.84 +- 0.47% in myocardial infarction and 3.00 +- 0.37% in angina pectoris, respectively, which showed significant low values in the latter two groups. MBF (ml/min/m2) = MBF/CO (%) x Cardiac index (CI). The mean value of MBF was 100.4 +- 12.7 ml/min/m2 in normals, 80.5 +- 21.1 in myocardial infarction and 77.3 +- 15.4 in angina pectoris, respectively, showing also significant low values in the latter two groups. Especially, MBF was most significant low in the groups of myocardial infarction with high serum CPK values. (author)

  8. Comparison of low-dose dobutamine stress echocardiography and single photon emission computed tomography and delayed contrast MRI in the diagnosis of myocardial viability: Meta-analysis

    International Nuclear Information System (INIS)

    Objective: To assess the diagnostic value of different imaging methods including low- dose dobutamine stress echocardiography, SPECT and contrast enhancement MRI with Meta-analysis in the diagnosis of myocardial viability. Methods: Articles published from 1998 to 2008 were searched in Cochrane library, Medline, Embase database, OVID database and CNKI for relevant English and Chinese articles. According to the criteria for diagnostic research published by Cochrane Method Group on screening and diagnostic tests, each article was critically screened and appraised, including the absolute numbers of true-positive, false-negative, tree-negative, and false-positive. Statistical analysis was performed employing Meta-test. Heterogeneity was tested, pooled weighted sensitivity and specificity and the corresponding 95% CI were calculated. Characteristic (SROC) curve was performed and the area under the curve was calculated. Finally, sensitivity analysis was performed. Results: Twenty-one of 438 retrieved articles were included, in which there were ten articles about Low-dose dobutamine stress echocardiography, and six articles about 99Tcm-MIBL/99Tcm-Tetrofosmin SPECT, and six articles about contrast enhancement MRI, and one of both 99Tcm-MIBL/99Tcm-tetrofosmin SPECT and contrast enhancement MRI. All groups had heterogeneity, and a random effects regression was developed. The pooled weighted sensitivity and specificity and area under SROC curve for low-dose dobutamine stress echocardiography to diagnose myocardial viability was 0.73(0.62-0.82)/0.82 (0.77-0.86) and 87.07% respectively. They were 0.82 (0.59-0.94)/ 0.77 (0.64-0.86) and 86.97% for 99Tcm-MIBI/99Tcm-Tetrofosmin SPECT respectively, while they were 0.94 (0.86-0.97)/0.75 (0.66-0.83) and 91.41% for contrast enhancement MRI respectively. Conclusion: As noninvasive testing technologies, low-dose dobutamine stress echocardiography and 99Tcm-MIBI/99Tcm-tetrofosmin SPECT and delayed contrast enhanced MRI allow the identification of viable myocardium, but delayed contrast enhanced MRI showed significant different pooled sensitivity in comparison to low-dose dobutamine stress echocardiography. (authors)

  9. Kinetic analysis of 18F-fluorodihydrorotenone as a deposited myocardial flow tracer: Comparison to thallium-201.

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Robert C.; Powers-Risius, Patricia; Reutter, Bryan W.; O' Neil, James P.; La Belle, Michael; Huesman, Ronald H.; VanBrocklin, Henry F.

    2004-03-01

    The goal of this investigation was to assess the accuracy of 18F-fluorodihydrorotenone (18F-FDHR) as a new deposited myocardial flow tracer and compare the results to those for 201Tl. Methods. The kinetics of these flow tracers were evaluated in 22 isolated, erythrocyte- and albumin-perfused rabbit hearts over a flow range encountered in patients. The two flow tracers plus a vascular reference tracer (131I-albumin) were introduced as a bolus through a port just above the aortic cannula. Myocardial extraction, retention, washout, and uptake parameters were computed from the venous outflow curves using the multiple indicator dilution technique and spectral analysis. Results. The mean initial extraction fractions of 18F-FDHR (0.85 +- 0.07) and 201Tl (0.87 +- 0.05) were not significantly different, although the initial extraction fraction for 18F-FDHR declined with flow (P < 0.0001), whereas the initial extraction fraction of 201Tl did not. Washout of 201Tl was faster (P < 0.001) and more affected by flow (P < 0.05) than 18F-FDHR washout. Except for initial extraction fraction, 18F-FDHR retention was greater (P < 0.001) and less affected by flow (P < 0.05) than 201Tl retention. Reflecting its superior retention, net uptake of 18F-FDHR was better correlated with flow than 201Tl uptake at both one and fifteen minutes after tracer introduction (P < 0.0001 for both comparisons). Conclusion. The superior correlation of 18F-FDHR uptake with flow indicates that it is a better flow tracer than 201Tl in the isolated rabbit heart. Compared to the other currently available positron-emitting flow tracers (82Rb, 13N-ammonia, and 15O-water), 18F-FDHR has the potential of providing excellent image resolution without the need for an on-site cyclotron.

  10. Study on different imaging time of late 201Tl thyroid imaging to differentiate malignant from benign thyroid nodules

    International Nuclear Information System (INIS)

    This study was undertaken to clarify better time to initiate the late 201Tl thyroid imaging to differentiate malignant thyroid nodules from benign ones. Thyroid images were obtained at 5 min, 1 and 3 hr after i.v. injection of 74 MBq of 201Tl chloride. The early (5 min) and late (1 or 3 hr) 201Tl images were compared in pathologically proven 38 malignant and 48 benign nodules of 83 patients. The lesion activity (LA) on the early image was visually graded as no uptake (-), slight uptake less than the surrounding thyroid tissue uptake (SITU) (±), uptake equal to the STTU (+), and uptake more than the STTU (++). The change of LA relative to the STTU from the early image to the late image was visually graded as decreasing (D), unchanged (U) or increasing (I) pattern when the LA was (±) to (++). The benign or malignant possibility at 1 hr and 3 hr in each lesion pattern was as follows: When the LA was (-) or D, the benign possibility was 95% (35/37) and 85% (39/46). When the LA was I, the malignant possibility was 96% (27/28) and 91% (21/23). When the LA is U, the diagnosis was equivocal: malignancy; 43% (9/21) at 1 hr and 59% (10/17) at 3 hr. The positive LA had a tendency to decrease with time irrespective of tumor character. The 1 hr image was statistically better than the 3 hr image as a late image. Comparative diagnosis of 5 min and 1 hr images with the criteria of I and U lesions being malignant and others being benign seems to be the best not to overlook malignant nodules: negative predictive value of 95% and sensitivity 95%. (author)

  11. Investigation of the biokinetics of thallium-201 and technetium-99m-stannous-pyrophosphate by experimentally induced myocardial infarction of the cat

    International Nuclear Information System (INIS)

    The radionuclide distributions of the imaging agents 201Tl and sup(99m)Tc-Sn-PyP were studied in the infarcted heart of the cat. After 24 h. experimentally induced myocardial infarction, tracer concentrations of about 100 myocardial tissue samples taken from each heart were determined. The distribution patterns of the two radionuclides were compared. (author)

  12. Experimental study of hypoxic preconditioning on 99Tcm-MIBI and 201Tl kinetics in cultured neonatal rat cardio-myocytes

    International Nuclear Information System (INIS)

    Objective: To study the effect of hypoxic preconditioning (HPC) on 99Tcm-MIBI and 201Tl kinetics in cultured neonatal rat cardio-myocytes. Methods: The protection of HPC was assayed on the model of hypoxia/reoxygenation (H/R) of cultured neonatal rat cardio-myocytes and the Trypan blue exclusion method was used to assess cell viability. Normal, hypoxic preconditioning and hypoxia/reoxygenation cardio-myocytes groups were studied. By measuring the diffused and released radioactivity of myocytes in different time intervals, the effect of HPC on 99Tcm-MIBI and 201Tl uptake and clearance kinetics in the myocytes was observed in various conditions. Results: Compared with H/R, the number of viable cells after HPC [(75.31 +- 3.45)% vs (55.50 +- 3.13)%, P 99Tcm-MIBI and 201Tl to a plateau level with a half-time of 12.8 min and 6.5 min, respectively. HPC caused a significant increase in uptake of 99Tcm-MIBI [normal control, (4852 +- 491) counts·min-1·mg-1 protein to HPC group, (6103 +- 170) counts·min-1·mg-1 protein; P 201Tl uptake [normal control, (3190 +- 183) counts·min-1·mg-1 protein to HPC group, (2120 +- 202) counts·min-1·mg-1 protein; P 99Tcm-MIBI and 201Tl were both retarded. Conclusions: These results suggested that the neonatal rat cardio-myocytes after HPC offered more capacity to tolerate the H/R damage and HPC could influence the 99Tcm-MIBI and 201Tl uptake and clearance

  13. Single photons on demand

    International Nuclear Information System (INIS)

    Quantum cryptography and information processing are set to benefit from developments in novel light sources that can emit photons one by one. Quantum mechanics has gained a reputation for making counter-intuitive predictions. But we rarely get the chance to witness these effects directly because, being humans, we are simply too big. Take light, for example. The light sources that are familiar to us, such as those used in lighting and imaging or in CD and DVD players, are so huge that they emit billions and billions of photons. But what if there was a light source that emitted just one photon at a time? Over the past few years, new types of light source that are able to emit photons one by one have been emerging from laboratories around the world. Pulses of light composed of a single photon correspond to power flows in the femtowatt range - a million billion times less than that of a table lamp. The driving force behind the development of these single-photon sources is a range of novel applications that take advantage of the quantum nature of light. Quantum states of superposed and entangled photons could lead the way to guaranteed-secure communication, to information processing with unprecedented speed and efficiency, and to new schemes for quantum teleportation. (U.K.)

  14. Precordial ST-segment depression during acute inferior myocardial infarction: clinical, scintigraphic and angiographic correlations

    International Nuclear Information System (INIS)

    The cause and associated pathophysiology of precordial ST-segment depression during acute inferior myocardial infarction (IMI) are controversial. To investigate this problem, electrocardiographic findings in 48 consecutive patients with acute IMI were prospectively compared with results of coronary angiography, submaximal exercise thallium-201 (201Tl) scintigraphy and multigated blood pool imaging, all obtained 2 weeks after IMI, and with clinical follow-up at 3 months. Patients were classified according to the admission ECG obtained 3.3 +/- 3.1 hours after the onset of chest pain. Twenty-one patients (group A) had no or 201Tl perfusion abnormalities (p201Tl defects or wall motion abnormalities in anterior or septal segments

  15. Detection of coronary artery disease using 12-lead electrocardiogram and simultaneous dual myocardial imaging with iodine-123-?-methyl iodophenyl-pentadecanoic acid (BMIPP) and thallium-201 in patients with unstable angina

    International Nuclear Information System (INIS)

    We investigated the usefulness of 12-lead electrocardiogram and simultaneous single-photon emission computed tomography (SPECT) with 123I-?-methyl iodophenyl-pentadecanoic acid (BMIPP) and thallium-201 (201Tl) for detecting coronary artery disease (CAD) in 54 consecutive patients with unstable angina. Discordant BMIPP uptake was defined as less 123I-BMIPP uptake than 201Tl uptake in 123I-BMIPP/201Tl dual SPECT. In the detection of CAD, ischemic electrocardiographic change during anginal attack had high sensitivity and low specificity, while discordant BMIPP finding had low sensitivity and high specificity. In patients showing ST depression during anginal attack, discordant BMIPP uptake showed high sensitivity and high specificity for detecting CAD. In conclusion, both 12-lead electrocardiogram during anginal attack and discordant BMIPP uptake are useful in detecting CAD in patients with unstable angina. (author)

  16. Defect images in stress thallium-201 myocardial scintigraphy in patients with complete left bundle branch block. Comparison of exercise stress and pharmacological stress

    International Nuclear Information System (INIS)

    Stress thallium-201 (201Tl) myocardial scintigraphy can demonstrate perfusion abnormalities, especially in the septum in patients with complete left bundle branch block (CLBBB) even with angiographically normal coronary arteries. Differences in the images between exercise and pharmacological stress 201Tl myocardial scintigraphy were evaluated in patients with CLBBB and normal coronary arteries. Forty-five patients with CLBBB underwent exercise stress using treadmill or pharmacological (adenosine triphosphate) stress 201Tl myocardial scintigraphy from October 1997 to February 2003. Patients with myocardial diseases were excluded, such as cardiomyopathy and coronary artery diseases detected by echocardiography and/or cardiac catheterization. The myocardial segment was classified according to the American Heart Association style for coronary artery disease. Peak blood pressure levels and heart rates were significantly higher in the exercise stress group than in the pharmacological stress group (p201Tl myocardial scintigraphy according to the stress method. Moreover, defects also occurred in areas other than the septum. Blood pressure and heart rate were involved in the mechanisms of defects in left bundle branch block. (author)

  17. Single photon source characterization with a superconducting single photon detector

    CERN Document Server

    Hadfield, R H; Miller, A J; Mirin, R P; Nam, S W; Schwall, R E; Stevens, M J; Gruber, Steven S.; Hadfield, Robert H.; Miller, Aaron J.; Mirin, Richard P.; Nam, Sae Woo; Schwall, Robert E.; Stevens, Martin J.

    2005-01-01

    Superconducting single photon detectors (SSPD) based on nanopatterned niobium nitride wires offer single photon counting at fast rates, low jitter, and low dark counts, from visible wavelengths well into the infrared. We demonstrate the first use of an SSPD, packaged in a commercial cryocooler, for single photon source characterization. The source is an optically pumped, microcavity-coupled InGaAs quantum dot, emitting single photons on demand at 902 nm. The SSPD replaces the second silicon Avalanche Photodiode (APD) in a Hanbury-Brown Twiss interferometer measurement of the source second-order correlation function, g (2) (tau). The detection efficiency of the superconducting detector system is >2 % (coupling losses included). The SSPD system electronics jitter is 170 ps, versus 550 ps for the APD unit, allowing the source spontaneous emission lifetime to be measured with improved resolution.

  18. Comparison of myocardial imaging with iodine-123-iodophenyl-9-methyl pentadecanoic acid and thallium-201-chloride for assessment of patients with exercise-induced myocardial ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Chouraqui, P.; Maddahi, J.; Henkin, R.; Karesh, S.M.; Galie, E.; Berman, D.S. (Cedars-Sinai Medical Center, Los Angeles, CA (USA))

    1991-03-01

    Iodine-123-iodophenyl-9-methyl-pentadecanoic acid (({sup 123}I)MPDA) and thallium-201 ({sup 201}Tl) were sequentially injected in 11 patients during exercise-induced myocardial ischemia. Simultaneous dual-energy planar images were obtained at 5 min, 3 and 5 hr. All studies were concordantly either positive (8/11) or negative (3/11) by both radionuclides. Exact agreement for segmental uptake was 93%, 94% and 94% for 5-min, 3- and 5-hr images, respectively. Exact agreement for defect reversibility by 3 and 5 hr were 95% and 92%. The initial defect contrasts and myocardial-to-lung ratios were similar by both agents but myocardial-to-liver ratio was lower by ({sup 123}I)MPDA at 5 min, which became similar to {sup 201}Tl at 5 hr. Normal percent myocardial clearances of both agents were comparable and significantly higher than those in defect zones. Thus ({sup 123}I)MPDA is suitable for myocardial imaging and correlates closely with {sup 201}Tl for initial postexercise myocardial uptake and defect reversibility. Defect reversibility appears to result from differential myocardial clearance from normal and ischemic regions.

  19. Prognostic Contribution of Exercise Capacity, Heart Rate Recovery, Chronotropic Incompetence, and Myocardial Perfusion Single-Photon Emission Computerized Tomography in the Prediction of Cardiac Death and All-Cause Mortality.

    Science.gov (United States)

    Arbit, Boris; Azarbal, Babak; Hayes, Sean W; Gransar, Heidi; Germano, Guido; Friedman, John D; Thomson, Louise; Berman, Daniel S

    2015-12-01

    Chronotropic incompetence, measured by the percentage (%) of heart rate (HR) reserve achieved (%HR reserve), abnormal HR recovery, reduced exercise capacity (EC), and myocardial perfusion single-photon emission computerized tomography (SPECT MPS) abnormalities are known predictors of all-cause mortality (ACM) and cardiac death (CD). The aim of this study was to determine if EC, %HR reserve, and HR recovery add incremental value to MPS in the prediction of ACM and CD. A total of 11,218 patients without valvular disease and not on ? blockers underwent symptom-limited exercise MPS. %HR reserve was (peak HR - rest HR)/(220 - age - rest HR) × 100, with %HR reserve exercise was considered abnormal. Poor EC was defined as exercise duration ?6 minutes (7 metabolic equivalents). Summed stress scores (SSSs) were calculated using a 20-segment, 5-point MPS model. Statistical analysis was performed using Cox regression models. There were 445 deaths (148 CD) during a mean follow-up of 3.2 ± 2.5 years. In multivariate analysis, the independent predictors of ACM were age, ?(2) = 154.81; EC, ?(2) = 74.00; SSS, ?(2) = 32.99; %HR reserve, ?(2) = 24.74; abnormal electrocardiogram at rest, ?(2) = 23.13; HR recovery, ?(2) = 18.45; diabetes, ?(2) = 17.75; and previous coronary artery disease, ?(2) = 11.85 (p ?0.0006). The independent predictors of CD were SSS, ?(2) = 54.25; EC, ?(2) = 49.34; age, ?(2) = 46.45; abnormal electrocardiogram at rest, ?(2) = 30.60; previous coronary artery disease, ?(2) = 20.69; Duke treadmill score, ?(2) = 19.50; %HR reserve, ?(2) = 11.43; diabetes, ?(2) = 10.23 (all p ?0.0014); and HR recovery, ?(2) = 5.30 (p = 0.0214). The exercise variables showed increases in Harrell's C static and net improvement reclassification, with EC showing the strongest incremental improvement in predicting ACM and CD (respective C-index 76.5% and 83.3% and net reclassification index 0.3201 and 0.4996). In conclusion, EC, %HR reserve, and HR recovery are independent predictors of ACM and CD and add incremental prognostic value to extent and severity of MPS. PMID:26482180

  20. Thallium-201 myocardial imaging in unstable angina and variant angina

    International Nuclear Information System (INIS)

    It is of clinical relevance in the coronary care unit to evaluate the potential role of 201Tl scintigraphy in patients with unstable angina. In the present chapter the authors discuss 1) the pattern of 201Tl scintigraphy in patients with unstable angina; and 2) the potential predictive value of 201Tl scintigraphy in identifying patients with unstable angina who have a poorer prognosis or greater tendency to subsequently develop acute myocardial infarction. All patients with unstable angina pectoris were purposely studied during the pain free period. It seemed conceivable that injecting 201Tl during an anginal attack would result in a high percentage of scintigraphic defects and probably diminish a potential discriminative value of the method. Moreover in clinical practice the majority of patients arrive at the coronary care unit some time after the last anginal attack. If a diagnostic test performed at this time could distinguish high and low risk patients, important therapeutic decisions might be made at the earliest possible times. (Auth.)

  1. Nanodiamond Emitters of Single Photons

    Directory of Open Access Journals (Sweden)

    Vlasov I.I.

    2015-01-01

    Full Text Available Luminescence properties of single color centers were studied in nanodiamonds of different origin. It was found that single photon emitters could be realized even in molecularsized diamond (less than 2 nm capable of housing stable luminescent center “silicon-vacancy.” First results on incorporation of single-photon emitters based on luminescent nanodiamonds in plasmonic nanoantennas to enhance the photon count rate and directionality, diminish the fluorescence decay time, and provide polarization selectivity are presented.

  2. Caffeine reduces dipyridamole-induced myocardial ischemia

    International Nuclear Information System (INIS)

    The mechanism of action of coronary vasodilation after dipyridamole may be based on inhibition of cellular uptake of circulating endogenous adenosine. Since caffeine has been reported to be a competitive antagonist of adenosine we studied the effect of caffeine on the outcome of dipiridamole-201Tl cardiac imaging in one patient. During caffeine abstinence dipyridamole induced myocardial ischemia with down-slope ST depressions on the ECG, and reversible perfusion defects on the scintigrams. When the test was repeated 1 wk later on similar conditions, but now shortly after infusion of caffeine (4 mg/kg), the ECG showed nodepressions, and the scintigrams only slight signs of ischemia. We conclude that when caffeine abstinence is not sufficient, the widespread use of coffee and related products may be responsible for false-negative findings in dipyridamole-201Tl cardiac imaging

  3. A study of thallium scintigraphy for myocardial infarction performed within 72 hours of attack

    International Nuclear Information System (INIS)

    In 40 cases undergoing 201Tl myocardial scanning within 72 hours of attack of myocardial infarction, a significant correlation was found between the infarct size determined by myocardial scanning and the size of the infarction estimated on the basis of ECG findings and serum enzymes. The group with high pulmonary capillary wedge pressure was the group with low Tl scores. The group showing dyskinesis and aneurysm in left ventriculography showed low Tl scores and a significant correlation between the ejection fraction calculated from left ventriculograms and the Tl score. The above date indicate that 201Tl myocardial scanning in the acute phase after attack of infarction reflects the infarction size and cardiac function. (Chiba, N.)

  4. Comparison of myocardial thallium and ?-methyl iodophenyl pentadecanoic acid (BMIPP) distribution in cardiomyopathy hamster

    International Nuclear Information System (INIS)

    The usefulness of fatty acid imaging in the detection of cardiomyopathy was evaluated by comparing thallium and BMIPP myocardial distribution in Bio 14.6 Syrian Hamster (25 week ages). Autoradiography was performed in 3 using 3.7 MBq (100 ?Ci) of 125I-BMIPP and 37 MBq (1 mCi) of 201TlCl. In vivo pin-hole imaging was performed in 3 using 37 MBq (1 mCi) of 123I-BMIPP and 37 MBq (1 mCi) of 201TlCl. In all cardiomyopathy hamsters, decreased uptake of BMIPP compared to that of thallium was demonstrated. These findings suggest dilated cardiomyopathy is associated with severe focal alternation in the substrate used for the performance of myocardial work. In conclusion, myocardial imaging using BMIPP may be useful for early detection of myocardial degeneration compared to thallium in patients with dilated cardiomyopathy. (author)

  5. [Myocardial involvement in rhabdomyolysis caused by acute heroin intoxication].

    Science.gov (United States)

    Melandri, R; De Tommaso, I; Zele, I; Rizzoli, D; Rapezzi, C; Pezzilli, R; Re, G; Fontana, G

    1991-06-01

    It is well known that heroin overdose may cause rhabdomyolysis. Sometimes a myocardial involvement complicates its course. We report a case of heroin intoxication followed by rhabdomyolysis associated with myocardial injury, with symptoms, laboratory findings, ECG and echocardiography features of non-Q wave infarction. However, a 201 Tl myocardial scintigraphy, performed after patient discharging, did not show any abnormality. We think that heroin has a direct myotoxic effect on both myocardium and skeletal muscle. Yet we cannot exclude that hypoxia, acidosis, vasoconstrictive substances released by muscle necrosis, or hypersensitivity reactions associated with heroin or some of its adulterants are involved in myocardial injury. PMID:1924987

  6. Study on the assessment and improvement of diagnostic efficacy of myocardial scintigraphy for ischemic heart diseases

    International Nuclear Information System (INIS)

    In order to improve the diagnostic efficacy of two nuclides, sup(99m)technetium pyrophoshate (sup(99m)Tc-PYP) and thallium 201 (201Tl) in the diagnosis of coronary ischemic diseases, their quantitative evaluation and loading methods were studied, and the scintigrams with these nuclides were compared with coronary angiograms (CA). With sup(99m)Tc-PYP, 22 cases (5 normals and 17 patients with coronary heart diseases (CHD)) were examined through the myocardium/thoracic vertebra (M/Th) ratio. The positive M/Th ratio was more than 1.2 and the best imaging time was 60-90 minutes after injection. The specificity of the sup(99m)Tc-PYP scintigram correlated well with CA but its sensitivity did not. The 201Tl uptake with the 201Tl scintigram using the regional cardiac muscle blood flow method was examined in 61 patients with CHD. In comparison with CA, the specificity of the 201Tl scintigram was 97-100% and its sensitivity was 50%. By experimental studies it was found, by using the myocardium/liver ratio on 12 dogs and the isocount display method on 10 patients with angina pectoris, that the glucose-insulin tolerance method increased the 201Tl uptake in the myocardium. It can be concluded that the M/Th ratio is useful in the diagnosis of unstable angina, but the quantitative method of 201Tl is not adequate to use as a diagnostic device. From the metabolic point of view, the further study, such as using PET, is needed because these scintigrams clearly reflect not only the coronary blood flow but also the myocardial metabolism. (author)

  7. Comparison of positron tomography and scintigraphy with 201Tl for delineation of the myocardium

    International Nuclear Information System (INIS)

    In a preliminary study, the delineation of myocardial infarctions using thallium-201 with a conventional gamma camera has been compared with the results obtained with a tomographic positron camera using rubidium-81. Six patients with documented myocardial infarcts were studied with both methods, collecting 300,000 counts per image. The four projections obtained sequentially with thallium required about 60 minutes. Four tomographic planes recorded simultaneously with positron system required about 20 minutes imaging time. The image quality was approximately the same for both systems, which demonstrated the lesions well. The positron system thus appears to be superior in performance and, in connection with digital methods, is capable of flexible extension to any number of simultaneous planes of focus and to reconstructive imaging

  8. Ramsey interference with single photons

    CERN Document Server

    Clemmen, Stéphane; Ramelow, Sven; Gaeta, Alexander L

    2016-01-01

    Interferometry using discrete energy levels in nuclear, atomic or molecular systems is the foundation for a wide range of physical phenomena and enables powerful techniques such as nuclear magnetic resonance, electron spin resonance, Ramsey-based spectroscopy and laser/maser technology. It also plays a unique role in quantum information processing as qubits are realized as energy superposition states of single quantum systems. Here, we demonstrate quantum interference of different energy states of single quanta of light in full analogy to energy levels of atoms or nuclear spins and implement a Ramsey interferometer with single photons. We experimentally generate energy superposition states of a single photon and manipulate them with unitary transformations to realize arbitrary projective measurements, which allows for the realization a high-visibility single-photon Ramsey interferometer. Our approach opens the path for frequency-encoded photonic qubits in quantum information processing and quantum communicati...

  9. Single-photon decision maker

    CERN Document Server

    Naruse, Makoto; Drezet, Aurelien; Huant, Serge; Aono, Masashi; Hori, Hirokazu; Kim, Song-Ju

    2015-01-01

    Decision making is critical in our daily lives and for society in general and is finding evermore practical applications in information and communication technologies. Herein, we demonstrate experimentally that single photons can be used to make decisions in uncertain, dynamically changing environments. Using a nitrogen-vacancy in a nanodiamond as a single-photon source, we demonstrate the decision-making capability by solving the multi-armed bandit problem. This capability is directly and immediately associated with single-photon detection in the proposed architecture, leading to adequate and adaptive autonomous decision making. This study makes it possible to create systems that benefit from the quantum nature of light to perform practical and vital intelligent functions.

  10. Single-photon decision maker

    Science.gov (United States)

    Naruse, Makoto; Berthel, Martin; Drezet, Aurélien; Huant, Serge; Aono, Masashi; Hori, Hirokazu; Kim, Song-Ju

    2015-08-01

    Decision making is critical in our daily lives and for society in general and is finding evermore practical applications in information and communication technologies. Herein, we demonstrate experimentally that single photons can be used to make decisions in uncertain, dynamically changing environments. Using a nitrogen-vacancy in a nanodiamond as a single-photon source, we demonstrate the decision-making capability by solving the multi-armed bandit problem. This capability is directly and immediately associated with single-photon detection in the proposed architecture, leading to adequate and adaptive autonomous decision making. This study makes it possible to create systems that benefit from the quantum nature of light to perform practical and vital intelligent functions.

  11. Adsorption kinetics of {sup 201}Tl and migration of {sup 99m}Tc in natural soils; Cinetica de adsorcion de {sup 201}Tl y migracion de {sup 99m}Tc en suelos naturales

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez N, C. E. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Fraccionamiento La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Monroy G, F.; Fernandez R, E.; Anguiano A, J., E-mail: estefany_rodriguezn@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    The safety is very important in facilities where radioactive wastes are stored. One of the necessary characteristics of the site where these wastes will be disposed is the soil permeability, since a waterproof terrain avoids the diffusion and radionuclide transport in the leakages case. The objective of this work is to study the adsorption kinetics of {sup 201}Tl and the migration of {sup 99m}Tc in natural soil samples. The adsorption kinetics was determined starting from the obtaining of the retention coefficient of the thallium (static method) at different contact times. The technetium diffusion was studied by means of the dynamic method with different soil particles sizes. The results showed that the thallium is totally adsorbed starting from 20 h of contact among this and the mean. On the other hand, the technetium is very mobile in the soil, since it was possible to extract the majority of the tracer with little solvent. Also, it was found that for each soil gram the double water will be needed to leach the technetium almost in its entirety. Moreover, influence exists of the particle size in the migration velocity from the radiotracer to the most mobile being in major sizes than 2 mm that in minor size. (Author)

  12. Development of a computer-aided diagnosis system using fuzzy inference in 201TlCl exercise myocardial scintigraphy

    International Nuclear Information System (INIS)

    We have been working on the development of a computer-aided diagnosis system for images in nuclear medicine by using artificial neural networks. A physician's diagnosis of coronary artery disease in nuclear cardiology is performed not only on the basis of imaging data but also includes other factors such as measurement data from exercise scintigraphy. Therefore, we propose an expert system that uses fuzzy inference to estimate the number of abnormal vessels in cases of single- or multi-vessel disease (including normal vessels) of the coronary arteries. The main characteristic of this system is that it integrates information from various sources, including the physician's impressions. In this study, we investigated the system's clinical effectiveness. Results indicated a rate of agreement between the system's confidence level of inference and the physician's diagnosis of 62.2% and a rate of sensitivity of 83% for coronary artery disease. The computer made it possible to utilize vague factors such as a physician's assessment based on experience and intuition. These results demonstrate the usefulness of our proposed technique. (author)

  13. Myocardial uptake of meta-(/sup 123/I)-iodobenzylguanidine ((/sup 123/I)-MIBG) in patients with myocardial infarct

    Energy Technology Data Exchange (ETDEWEB)

    Fagret, D.; Comet, M.; Wolf, J.E.

    1989-09-01

    Meta-/sup 123/I-iodobenzylguanidine (/sup 123/I-MIBG), which is an analog of norepinephine, can be used to evaluate the integrity and function of sympathetic nerve endings in the heart. Myocardial uptake of /sup 123/I-MIBG was studied in 30 myocardial infarction patients and compared with the distribution of blood flow assessed with /sup 201/Tl. It was found that when a cold defect appeared on the /sup 201/Tl scintigram, its localization was identical to the cold defect on the /sup 123/I-MIBG scintigram. On the other hand, in three cases, a defect was found on the /sup 123/I-MIBG scintigram, corresponding to the electrocardiographic localization of the infarct, whereas the /sup 201/Tl scintigram was normal. Most strikingly, the present study shows that drugs (antagonists of the adrenergic receptors, calcium antagonists, amiodarone) decrease or even abolish (as in the case of labetalol) myocardial uptake of /sup 123/I-MIBG. Consequently, any interpretation of the /sup 123/I-MIBG scintigram must take into account the treatment administered. (orig.).

  14. Usefulness of 201Tl chloride quantitative gated SPECT in patients with cardiac sarcoidosis

    International Nuclear Information System (INIS)

    To examine the usefulness of thallium-201 quantitative gated SPECT (QGS) in patients with cardiac sarcoidosis, thirteen patients with systemic sarcoidosis, were examined by thallium-201 QGS and echocardiography. They were divided into two groups, A and B, with or without cardiac involvement of sarcoidosis according to the Japanese Ministry of Health and Welfare guidelines for cardiac sarcoidosis. Distribution abnormality was detected both in group A and group B, suggesting cardiac involvement caused by sarcoidosis in both groups, and the unreliability of these guidelines. The left ventricular (LV) wall was divided into 5 segments. The overall agreement between thallium-201 QGS and echocardiography for regional wall motion assessment of the LV was 72% (44/65 segments) suggesting the reliability of thallium-201 QGS for regional wall motion measurement. Among 44 segments with distribution abnormality, 17 segments had wall motion abnormality. Distribution abnormality with wall motion abnormality may reflect irreversible myocardial damage such as scar-like lesion, whereas distribution abnormality without wall motion abnormality may reflect the inflammatory stage, which can respond to steroid therapy. Thallium-201 QGS plays an important role in the diagnosis and follow up of cardiac involvement in patients with sarcoidosis, since this method is noninvasive, can be performed repeatedly and is suitable for simultaneous assessment of regional/total function and myocardial damage of the left LV. (author)

  15. Myocardium scanning with 201TL-chloride in ischemic heart disease

    International Nuclear Information System (INIS)

    Results of myocardial scanning with 210TL-chloride in ischemic herart disease are repoorted. An avearge dose of 500 microcurie and antero-posterior or lateral projection scanning with coloured registration are recommended. The scintigraphic pattern of the normal myocardium and the pathological changes, manifested by reduced isotope fixation, depending on the severity of the damage, are described. The diffuse pathological changes in the myocardium in ischemic heart disease are manifested by diffuse hypofixation of the radionuclide. The focal lesions in ischemic heart disease were manifested by characteristic changes: the infarctions of the posterior wall show a relatively clear scanographic picture on antero-posterior projection, with cold or cool zones in the median sections of the myocardium picture. Infarctions of the anterior myocardial wall, depending on how sizable they are, on antero-posterior projection are seen to occupy the lateral and central parts of the heart muscle. In the left oblique projection the pathologic process is projected frontally and centrally. (A.B.)

  16. Single photon searches at PEP

    Energy Technology Data Exchange (ETDEWEB)

    Hollebeek, R.

    1985-12-01

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented.

  17. Single photon searches at PEP

    International Nuclear Information System (INIS)

    The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented

  18. Exercise study of thallium-201 myocardial imaging and coronary arteriography

    International Nuclear Information System (INIS)

    Myocardial imaging with intravenous thallium-201 (Tl) was performed following bycycle ergometer exercise (Ex) and redistribution study (Rd) was performed after 4 hours of injection in 16 patients suspected coronary artery disease (CAD). Of 5 patients with no or insignificant CAD (= 75% diameter stenosis, 6 with angina pectoris, 5 with old myocardial infarction), 6(55%) had Ex Tl defect (Sensitivity 55%), 5 of 6 patients (83%) had significant collateral circulation, and 7(64%) had Ex ST-segment depression. We conclude that positive Ex Tl-myocardial imaging is highly suggestive of CAD (Predictive value 100%). (author)

  19. False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion

    Energy Technology Data Exchange (ETDEWEB)

    Smits, P.; Corstens, F.H.; Aengevaeren, W.R.; Wackers, F.J.; Thien, T. (University Hospital Nijmegen (Netherlands))

    1991-08-01

    The vasodilator effect of intravenously administered dipyridamole may be caused by an increase in endogenous plasma adenosine levels. The authors evaluated the effect of caffeine, an adenosine receptor antagonist, on the diagnostic results of dipyridamole-201Tl myocardial imaging in eight patients with coronary artery disease. Caffeine infusion significantly attenuated the dipyridamole-induced fall in blood pressure and the accompanied increase in heart rate. The infusion of dipyridamole alone resulted in chest pain and ST-segment depressions on the electrocardiogram in four patients, whereas none of these problems occurred when the tests were repeated after caffeine. In six of eight patients, caffeine was responsible for false-negative dipyridamole-201Tl tests. Semiquantitive scores of the dipyridamole-induced 201Tl perfusion defects were decreased by caffeine from 9.0 {plus minus} 0.9 to 2.0 {plus minus} 1.1 points (p less than 0.05). Computerized analysis revealed a caffeine-mediated reduction in the percent reversibility of the images from 46% {plus minus} 16% to 6% {plus minus} 10% (p less than 0.05). They conclude that the use of caffeinated products prior to dipyridamole-201Tl testing may be responsible for false-negative findings.

  20. False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion

    International Nuclear Information System (INIS)

    The vasodilator effect of intravenously administered dipyridamole may be caused by an increase in endogenous plasma adenosine levels. The authors evaluated the effect of caffeine, an adenosine receptor antagonist, on the diagnostic results of dipyridamole-201Tl myocardial imaging in eight patients with coronary artery disease. Caffeine infusion significantly attenuated the dipyridamole-induced fall in blood pressure and the accompanied increase in heart rate. The infusion of dipyridamole alone resulted in chest pain and ST-segment depressions on the electrocardiogram in four patients, whereas none of these problems occurred when the tests were repeated after caffeine. In six of eight patients, caffeine was responsible for false-negative dipyridamole-201Tl tests. Semiquantitive scores of the dipyridamole-induced 201Tl perfusion defects were decreased by caffeine from 9.0 ± 0.9 to 2.0 ± 1.1 points (p less than 0.05). Computerized analysis revealed a caffeine-mediated reduction in the percent reversibility of the images from 46% ± 16% to 6% ± 10% (p less than 0.05). They conclude that the use of caffeinated products prior to dipyridamole-201Tl testing may be responsible for false-negative findings

  1. Use of myocardial perfusion imaging and estimation of associated radiation doses in Germany from 2005 to 2012

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, O.; Burchert, W. [University Hospital of the Ruhr University Bochum, Institute of Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Bad Oeynhausen (Germany); Bengel, F.M. [Hanover Medical School, Department of Nuclear Medicine, Hanover (Germany); Hacker, M. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Vienna (Austria); Schaefer, W. [Kliniken Maria Hilf GmbH, Clinic of Nuclear Medicine, Moenchengladbach (Germany); Collaboration: Working Group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine

    2014-05-15

    For several years the Working Group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine has been performing a regular survey to obtain information on technique, utilization and development of myocardial perfusion scintigraphy (MPS). Currently, data of six surveys from 2005 to 2012 are available. The aim of this paper is to deliver a general and comprehensive overview of all surveys documenting the course of patient doses over time and the development of the method. A one-page questionnaire with number of MPS patients, number of stress and rest MPS, referral structure and several technical issues was sent to all centres performing MPS in Germany and evaluated. With the data on protocol utilization, effective MPS patient doses were estimated. MPS per million population (pmp) varied between 2,380 and 2,770. In 2012, MPS pmp showed a slight increase for the first time. From 2005 to 2009 the angiography to MPS ratio increased from 3.4 to 4.4, and the revascularization to MPS ratio decreased from 0.66 to 0.53. In 2012, both indices demonstrated an opposite trend for the first time (4.1 and 0.55). A total of 108 centres participated in all surveys. They showed an increase in MPS patients of 4.0 % over the reporting period. In 2012, more than 50 % of the centres experienced no change or an increase in MPS numbers. The leading single competitor was MRI, followed by angiography and stress echocardiography. {sup 201}Tl studies have decreased since 2005 from 20 to 5 %. {sup 99m}Tc MPS studies showed a mild increase in 2-day protocols. In 2012, the average effective dose per patient was estimated at 7.4 mSv. Due to the decreasing use of {sup 201}Tl, a mild decline over the observation period can be documented. Dynamic exercise stress was the most common stress test and adenosine the leading pharmacological stress agent, with a growing percentage. In 2012, the regadenoson percentage was 9 %. Gated single photon emission computed tomography (SPECT) noted an increasing acceptance with >70 % in 2012. The segmental scoring of perfusion studies had a low acceptance. Ambulatory care cardiologists represented the major referral group. Germany has a moderate to moderate-high MPS utilization rate. Nevertheless, coronary artery disease (CAD) diagnosis and disease management are dominated by angiography. The survey data reveal a positive trend in MPS and a decrease in average patient dose reflecting good practice with guideline adherence, the implementation of technical improvements and success in training. (orig.)

  2. Teleportation using squeezed single photons

    OpenAIRE

    Branczyk, Agata M.; Ralph, T C

    2008-01-01

    We present an analysis of squeezed single photon states as a resource for teleportation of coherent state qubits and propose proof-of-principle experiments for the demonstration of coherent state teleportation and entanglement swapping. We include an analysis of the squeezed vacuum as a simpler approximation to small-amplitude cat states. We also investigate the effects of imperfect sources and inefficient detection on the proposed experiments.

  3. Imaging of cocaine-induced global and regional myocardial ischemia

    International Nuclear Information System (INIS)

    Severe and often fatal cardiac complications have been reported in cocaine users with narrowed coronary arteries caused by atherosclerosis as well as in young adults with normal coronaries. The authors have found that in normal dogs cocaine induces severe temporary hypoperfusion of the left ventricle as indicated by a significantly lower 201Tl concentration compared to the baseline state. The most significant decrease in uptake occurred 5 min after injection and was more pronounced in the septal and apical segments. Following intravenous administration of cocaine, instead of gradual disappearance of 201Tl from the left ventricle, there was continuous increase in 201Tl concentration in the left ventricle. These imaging experiments indicate that the deleterious effects of cocaine on the heart are probably due to spasm of the coronaries and decreased myocardial perfusion. Since spasm of the large subpericardial vessels does not seem to explain the magnitude of the increased coronary resistance and decreased coronary flow after cocaine as described in the literature, it is suggested that microvascular spasm of smaller vessels plays a major role in the temporary decrease in perfusion. The data may also suggest that severe temporary myocardial ischemia is probably the initiating factor for the cardiac complications induced by cocaine

  4. Myocardial perfusion imaging for the detection of coronary heart disease

    International Nuclear Information System (INIS)

    A method of myocardial perfusion imaging using 201Tl is described. Thallium is able to substitute for potassium in biological systems including transport by the sodium--potassium ATP-ase system. The high extraction efficiency of the heart for 201Tl offers a method whereby a tracer may be administered intravenously and is concentrated to a significant degree by the heart. However, only about 3 to 4 percent of the dose administered lodges in the myocardium. Experiments with dogs indicated that the regional distribution of Tl in the heart reflects the regional distribution of blood flow. The goal is to develop a procedure that can detect those patients with significant disease prior to the onset of a catastrophic event and studies are being undertaken to improve the sensitivity of the method for the detection of smaller lesions in the myocardium

  5. Myocardial SPECT in children with sickle cell disease

    International Nuclear Information System (INIS)

    Aim: While cerebral and bones strokes are well documented in children with sickle cell disease (SCD), impairment of myocardial perfusion is an unknown complication. Conventional techniques such as exercise testing and echocardiography have a low sensitivity and specificity to detect myocardial ischemia in patients with SCD. The aim of this prospective study was to assess myocardial perfusion with 201Tl SPECT in children with SCD. Materials and Methods: Twenty-two patients, aged 12 ± 4 years, were included. Myocardial perfusion was assessed by 201Tl SPECT after stress and 3 hours later after reinjection on a single head gammacamera equipped with a LEAP collimator (64x64 matrix size format, 30 projections over 1800, 30 seconds per step). Left ventricular ejection fraction (LVEF) was assessed by equilibrium radionuclide angiography at rest on the same day. Results: Myocardial perfusion was impaired in 13/22 patients: 8 had reversible defects and 5 had fixed defects. The left ventricular cavity was dilated in 13/22 patients. The mean LVEF was 63 ± 9%. There was no relationship between myocardial perfusion and left ventricular dilation or function. Conclusion: Myocardial perfusion is frequently impaired in children with SCD. Treatment with hydroxyurea should be considered in SCD patients with perfusion defects

  6. Assessment of myocardial fatty acid metabolism in patients with vasospastic angina using 123I-BMIPP myocardial SPECT

    International Nuclear Information System (INIS)

    Myocardial perfusion and fatty acid metabolism may be unpaired in the patients of vasospastic angina (VSA), because abnormal regional wall motion of left ventricle has been shown in some cases of VSA without apparent history of myocardial infarction. To study the clinical utility of 123I-BMIPP scintigraphy in diagnosis of myocardial ischemia in VSA, both 123I-BMIPP (rest) and 201Tl (exercise) SPECT were performed in the 20 patients of VSA diagnosed by coronary angiography. Defect scores were calculated visually from the 17 segments of myocardial images and were compared with patient's anginal history, period from last attack, numbers of attack, left ventricular (LV) ejection fraction and severity of regional LV wall motion abnormality. 123I-BMIPP SPECT images showed decreased tracer uptake in 14 cases of 20 (70%) VSA patients. Exercise 201Tl SPECT images showed decreased tracer uptake in 3 cases of 20 (15%) of patients. Severity of regional LV wall motion abnormality was correlated with defect score of BMIPP. Though total defect score of BMIPP did not correlate with patient's anginal history, number of symptoms and LV ejection fraction, correlated inversely with period from last attack. It was suggested that 123I-BMIPP myocardial SPECT images in VSA patients showed 'memories' of myocardial ischemic damages induced by vasospasm. In summary, 123I-BMIPP myocardial SPECT images could be a useful test for diagnosis and evaluation of VSA. (author)

  7. Factors affecting the myocardial activity acquired during exercise SPECT with a high-sensitivity cardiac CZT camera as compared with conventional Anger camera

    International Nuclear Information System (INIS)

    Injected doses are difficult to optimize for exercise SPECT since they depend on the myocardial fraction of injected activity (MFI) that is detected by the camera. The aim of this study was to analyse the factors affecting MFI determined using a cardiac CZT camera as compared with those determined using conventional Anger cameras. Factors affecting MFI were determined and compared in patients who had consecutive exercise SPECT acquisitions with 201Tl (84 patients) or 99mTc-sestamibi (87 patients) with an Anger or a CZT camera. A predictive model was validated in a group of patients routinely referred for 201Tl (78 patients) or 99mTc-sestamibi (80 patients) exercise CZT SPECT. The predictive model involved: (1) camera type, adjusted mean MFI being ninefold higher for CZT than for Anger SPECT, (2) tracer type, adjusted mean MFI being twofold higher for 201Tl than for 99mTc-sestamibi, and (3) logarithm of body weight. The CZT SPECT model led to a +1 ± 26 % error in the prediction of the actual MFI from the validation group. The mean MFI values estimated for CZT SPECT were more than twofold higher in patients with a body weight of 60 kg than in patients with a body weight of 120 kg (15.9 and 6.8 ppm for 99mTc-sestamibi and 30.5 and 13.1ppm for 201Tl, respectively), and for a 14-min acquisition of up to one million myocardial counts, the corresponding injected activities were only 80 and 186 MBq for 99mTc-sestamibi and 39 and 91 MBq for 201Tl, respectively. Myocardial activities acquired during exercise CZT SPECT are strongly influenced by body weight and tracer type, and are dramatically higher than those obtained using an Anger camera, allowing very low-dose protocols to be planned, especially for 99mTc-sestamibi and in non-obese subjects. (orig.)

  8. Analysis of papillary muscle images on planar thallium-201 myocardial scintigrams in various heart diseases

    International Nuclear Information System (INIS)

    201Tl myocardial imaging can, noninvasively, visualize the various cardiac structures such as the left ventricle, right ventricle and, occasionally, the atrium. We have noted that certain patients exhibit a prominent appearance of the papillary muscle on a scintigram. Thus, we analyzed 201Tl myocardial scintigrams for evidence of activity which corresponded to the anterolateral (A-PM) and posteromedial (P-PM) papillary muscles. Twenty normal subjects, 81 patients with ischemic heart disease (IHD), 11 with hypertrophic cardiomyopathy (HCM) and 13 with dilated cardiomyopathy (DCM) were examined. Patients with DCM had rest imaging only, while the remaining ones performed exercise studies. The prevalence of a positive A-PM image was not high (9%-23%) and there was no significant difference among groups. The P-PM was seen in only 15% of the normal group and in 18% of the HCM group, while the prevalence was high in the IHD (34.6%) and DCM (53.8%) groups. In the IHD, the positive images of the P-PM were largely from the sub-group with single vessel left anterior descending (LAD) coronary artery disease (78.9%). However, even in the presence of a defect in the left ventricular wall supplied by the LAD coronary artery, the patients with multi-vessel coronary artery disease did not tend to disclose the P-PM on the scintigram (30.8%). Thus, we conclude that positive P-PM imaging on a planar 201Tl myocardial scintigram is frequently observed under some cardiac states and seems to be related to reduced wall motion, sound blood supply to the P-PM and the existence of a defect in the anterior left ventricular wall overlapping the P-PM. When we analyze the planar 201Tl myocardial scintigram, not only the left and right ventricles, but also the PM should be assessed. (orig.)

  9. Effect of nicardipine on painless myocardial ischemia

    International Nuclear Information System (INIS)

    201Tl myocrdial scintigraphy was performed in 29 patients with coronary heart diseaes and painless myocardial ischemic episodes revealed during a long-term monitoring of ST segment. The paintless ST segment depression episodes and long high-amplitude painless ST segment elevations were found to be indicative of a significant severity of pathological processes in the myocardium. A 12-day nicardipine monotherapy produced antianginal and hypotensive effects and contributed to decrease in the frequency, duration, and amplitude of painless ST-segment depressions and in the duration of paintless ST-segment elevations

  10. Better Randomness with Single Photons

    CERN Document Server

    Oberreiter, Lukas

    2014-01-01

    Randomness is one of the most important resources in modern information science, since encryption founds upon the trust in random numbers. Since it is impossible to prove if an existing random bit string is truly random, it is relevant that they be generated in a trust worthy process. This requires specialized hardware for random numbers, for example a die or a tossed coin. But when all input parameters are known, their outcome might still be predicted. A quantum mechanical superposition allows for provably true random bit generation. In the past decade many quantum random number generators (QRNGs) were realized. A photonic implementation is described as a photon which impinges on a beam splitter, but such a protocol is rarely realized with non-classical light or anti-bunched single photons. Instead, laser sources or light emitting diodes are used. Here we analyze the difference in generating a true random bit string with a laser and with anti-bunched light. We show that a single photon source provides more r...

  11. Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    The effect of verapamil myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated exercise myocardial 201TlSPECT (EX-Tl). EX-Tl was performed before and after 8.1±6.1 weeks of oral administration of verapamil (240 mg/day) on 20 patients with HCM who showed transient 201Tl perfusion defects under control conditions. SPECT images were divided into nine segments. The 201Tl perfusion defect was visually scored and evaluated for four grades in each segment and the sum total grade was calculated as the defect score. Transient dilation index was calculated as a reflection of subendocardial ischemia. Improvements in defect score were demonstrated in 18 of 20 patients after administration of verapamil. The mean defect score decreased significantly from 5.1±2.3 to 2.5±2.4 (p<0.001). Although 18 of 20 patients showed abnormal transient dilation index under control conditions, 16 showed improvement and 12 were normalized after verapamil therapy. Mean transient dilation index decreased from 1.24±0.19 to 1.08±0.10 (p<0.01). Verapamil improves myocardial ischemia on patients with HCM. (author)

  12. Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Effect of verapamil on myocardial ischemia in patients with hypertrophic cardiomyopathy (HCM) was evaluated by exercise stress myocardial 201Tl SPECT (EX-Tl). EX-Tl was performed before and after 8.8 weeks of oral verapamil (240 mg/day) in 12 patients with HCM who showed transient 201Tl perfusion defects under control conditions. 201Tl perfusion defect was visually scored and judged for 4 grades as normal (0), mild defect (1), moderate defect (2), and severe defect (3). Transient dilation index (TDI) was calculated as an index of subendocardial ischemia. Improvements of defect score were demonstrated in 10 patients after administration of verapamil. Two patients showed no change of defect score. Mean defect score decreased significantly from 5.50 to 3.03 (p<0.001). Although 11 of 12 patients showed abnormal TDI under control conditions, 10 of these revealed improvements of TDI and 7 of the 10 disclosed normal TDI after verapamil. Mean TDI decreased from 1.263 to 1.090 significantly (p<0.01). In conclusion, verapamil may improve myocardial ischemia in patients with HCM. (author)

  13. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous 99mTc/201Tl SPECT imaging: A Monte Carlo simulation study

    International Nuclear Information System (INIS)

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous 99mTc/201Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of 201Tl (77±10% keV) and 99mTc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results

  14. Using adaptive neuro-fuzzy inference system technique for crosstalk correction in simultaneous 99mTc/201Tl SPECT imaging: A Monte Carlo simulation study

    Science.gov (United States)

    Heidary, Saeed; Setayeshi, Saeed

    2015-01-01

    This work presents a simulation based study by Monte Carlo which uses two adaptive neuro-fuzzy inference systems (ANFIS) for cross talk compensation of simultaneous 99mTc/201Tl dual-radioisotope SPECT imaging. We have compared two neuro-fuzzy systems based on fuzzy c-means (FCM) and subtractive (SUB) clustering. Our approach incorporates eight energy-windows image acquisition from 28 keV to 156 keV and two main photo peaks of 201Tl (77±10% keV) and 99mTc (140±10% keV). The Geant4 application in emission tomography (GATE) is used as a Monte Carlo simulator for three cylindrical and a NURBS Based Cardiac Torso (NCAT) phantom study. Three separate acquisitions including two single-isotopes and one dual isotope were performed in this study. Cross talk and scatter corrected projections are reconstructed by an iterative ordered subsets expectation maximization (OSEM) algorithm which models the non-uniform attenuation in the projection/back-projection. ANFIS-FCM/SUB structures are tuned to create three to sixteen fuzzy rules for modeling the photon cross-talk of the two radioisotopes. Applying seven to nine fuzzy rules leads to a total improvement of the contrast and the bias comparatively. It is found that there is an out performance for the ANFIS-FCM due to its acceleration and accurate results.

  15. 99mTc-MIBI (RP-30) to define the extent of myocardial ischemia and evaluate ventricular function

    International Nuclear Information System (INIS)

    99mTc-MIBI, a new myocardial perfusion agent, is a technetium labeled isonitrile derivative. We have taken advantage of the physical characteristics of 99mTc to combine at rest, post infarction, ventricular function studies with analysis of perfusion. We have studied at rest and at stress, 22 patients with coronary artery disease selected on the basis of an abnormal coronary angiogram or on the basis of a positive exercise ECG stress test for symptomatic angina. We have also studied at rest only, 20 patients with a previous myocardial infarction. A comparative thallium planar scintigraphy was obtained for all patients. The sensitivity of 99mTc-MIBI scintigraphy for detecting individual vessel lesions at stress was 88% as compared with 83% for 201Tl. Sensitivity was higher in patients with previous myocardial infarction (93% for the 2 isotopes) than in patients without (85% for 99mTc-MIBI versus 81% for 201Tl). Segmental myocardial correspondence between 99mTc-MIBI and 201Tl was very close (92%). The overall sensitivity for the detection of acute myocardial infarction reached respectively 91% for 99mTc MBIB and 87% for 201Tl. The specificity in the regions corresponding to arteries not involved was excellent for both tracers as we did not observe any false positive result. The correlation between first pass left ventricular ejection fraction obtained with 99mTc-MIBI and equilibrium left ventricular ejection fraction obtained with 99mTc red cells was excellent (r=0.96). It was not as good but was still satisfactory for the right ventricle (r=0.75). By comparison of diastolic and systolic frames, gated tomography provides analysis of regional wall motion and wall thickening. (orig.)

  16. Single photon response of photomultiplier tubes

    International Nuclear Information System (INIS)

    Beta or gamma rays, when directly incident on the window of an optically shielded photomultiplier tube, yield a typical single photon spectrum. The single photons are possibly generated in the glass window of the photomultiplier tube through excitation of atoms in glass by electrons. The coincidence resolving time has also been measured with a 60Co gamma source and a pair of optically shielded photomultiplier tubes detecting single photons. (orig.)

  17. Spectral compression of single photons

    CERN Document Server

    Lavoie, Jonathan; Wright, Logan G; Fedrizzi, Alessandro; Resch, Kevin J

    2013-01-01

    Photons are critical to quantum technologies since they can be used for virtually all quantum information tasks: in quantum metrology, as the information carrier in photonic quantum computation, as a mediator in hybrid systems, and to establish long distance networks. The physical characteristics of photons in these applications differ drastically; spectral bandwidths span 12 orders of magnitude from 50 THz for quantum-optical coherence tomography to 50 Hz for certain quantum memories. Combining these technologies requires coherent interfaces that reversibly map centre frequencies and bandwidths of photons to avoid excessive loss. Here we demonstrate bandwidth compression of single photons by a factor 40 and tunability over a range 70 times that bandwidth via sum-frequency generation with chirped laser pulses. This constitutes a time-to-frequency interface for light capable of converting time-bin to colour entanglement and enables ultrafast timing measurements. It is a step toward arbitrary waveform generatio...

  18. Biokinetics of 201Tl

    International Nuclear Information System (INIS)

    In retention of Tl in blood is similar to that of K. Animal experiments and studies in humans have shown a half-life of 5 min for Tl elimination from blood. In contrast, renal clearance is only 4% during the first 24 h. After i.v. application, Tl is quickly distributed throughout the organism with the highest concentrations in the kidneys. In humans, the biological half-live is 9.8 d, i.e. the effective half-life is 5 h. Tl biokinetics can be influenced by various factors and by certain drugs. (MG)

  19. The value of dipyridamole 201TI SPECT myocardial perfusion imaging in ischemicc adult viral myocarditis

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to explore the characteristics of dipyridamole 201Tl SPECT myocardial perfusion imaging in patients clinically suspected of ischemic adult viral myocarditis (IAVM) based on electrocardiogram (ECG) changes. Methods: Seventy-nine patients.age range 19-55, were studied in their post. IAVM sequelae period. All patients underwent pharmacologically stressed 201Tl SPECT myocardial perfusion imaging after infusing 0.56 mg dipyridamole/kg intravenous iu 4 min. The early and delayed SPECT images were acquired respectively at 10 min and 240 min after 201Tl injection. Three-dimen-sional reconstructions of the original images were analyzed and reported by two or more experienced nuclear medicine physicians. The results of imaging between male and female genders were compared using ?2-test with SAS 8.1 software. Results: There were no abnormal myocardial perfusion findings in the early stress images in all patients. In the delayed study, however, 43.04% (34/79) of patients had abnormal results with reversed perfusion defects in 36 segments, including 9 segments (25.00%) in the anterior wall.11 segments (30.56%) in the inferior wall, 8 segments (22.22%) in the antero-septal wall, 4 segments (11.11%) in the antero-lateral wall, and 4 segments (11.11%) in the apex. The perfusion defect of single segment was found in 32 patients. Reversed defects were identified in 70.83% (17/24) of male and 30.91% (17/55) of female. There was a significant difference in proportion of abnormal findings between male and female genders (?2=10.86. P201Tl SPECT mvocardial perfusion imaging may have a value for diagnosis and treatment of the ischemic adult viral myocarditis. The ECG ST-T changes found in female may have higher false positive results and cautions should be taken. (authors)

  20. Clinical usefulness of the technetium-99m/thallium-201 overlap on simultaneous dual SPECT in reperfusion after thrombolytic therapy for acute myocardial infarction

    International Nuclear Information System (INIS)

    In this study, the clinical usefulness of the technetium-99m/thallium-201 (99mTc-PYP/201Tl-Cl) overlap on simultaneous dual SPECT in reperfusion after thrombolytic therapy for acute myocardial infarction was evaluated. The subjects were 14 patients with acute myocardial infarction who had not had myocardial infarction. All patients had chest pain that persisted more than 1 hour and showed electrocardiographic ST elevation. Myocardial scintigraphy was performed on the 4th day of the attack, at 81±35 hours after reperfusion on average. Three hours 50 min after intravenous injection of 740 Mbq 99mTc-PYP, 111 Mbq 201Tl-Cl was intravenously injected, and simultaneous dual SPECT was performed after 10 min. In all short axis SPECT image which showed 99mTc-PYP accumulation, the area of 99mTc-PYP accumulation (Tc hot), the overlap area of 99mTc-PYP and 201Tl-Cl accumulation (overlap), and the total area of 99mTc-PYP and 201Tl-Cl accumulation in the short axis SPECT images were calculated. The relationships between these parameters and the peak creatinine kinase (CK), changes in wall motion abnormalities observed by M-mode echocardiography, and the 4-hour delayed image by 201Tl-Cl exercise scintigraphy performed about one month after the attack were evaluated. The results were both parameters of overlap/Tc hot and overlap/total were negatively correlated with the peak CK, overlap/Tc hot and overlap/total were positively correlated with wall motion scores ratio (WMSR), and overlap/Tc hot was positively correlated with Tl uptake (d)/Tc hot, and the acute overlap region was evaluated to be viable cardiac muscles one month after the attack. These results demonstrated that the 99mTc-PYP/201Tl-Cl overlap on simultaneous dual SPECT in reperfusion after thrombolytic therapy for acute myocardial infarction indicates the presence of viable cardiac muscles, showing that this method is useful for judgment of the effects of reperfusion. (author)

  1. Study of single photon production at AMY

    International Nuclear Information System (INIS)

    Using 148 pb-1 data collected by the AMY detector, we have observed 4 single photon production events, while 4.0 events are expected from e+e- ? ???-bar. So far, we observed no significant excess of single photon production events over the Standard Model prediction. (J.P.N.)

  2. Hiding Single Photons with Spread Spectrum Technology

    International Nuclear Information System (INIS)

    We describe a proof-of-principal experiment demonstrating the use of spread spectrum technology at the single photon level. We show how single photons with a prescribed temporal shape, in the presence of interfering noise, may be hidden and recovered.

  3. Hiding Single Photons With Spread Spectrum Technology

    OpenAIRE

    Belthangady, Chinmay; Chuu, Chih-Sung; Yu, Ite A.; Yin, G. Y.; Kahn, J M; Harris, S.E.

    2010-01-01

    We describe a proof-of-principal experiment demonstrating the use of spread spectrum technology at the single photon level. We show how single photons with a prescribed temporal shape, in the presence of interfering noise, may be hidden and recovered.

  4. Physiological studies of environmental pollutants. Progress report, September 1, 1975--May 31, 1976. [/sup 210/Po, /sup 203/Pb, /sup 201/Tl, /sup 207/Bi, /sup 65/Zn

    Energy Technology Data Exchange (ETDEWEB)

    Lengemann, F W; Wentworth, R A

    1976-01-01

    In the past year we have looked at the transfer of some members of the actinide decay series into milk of goats. These were /sup 210/Po, /sup 203/Pb, /sup 201/Tl and /sup 207/Bi. All of these appeared in milk after oral ingestion but at levels less than 1 percent per liter. In addition we have looked at the transfer of /sup 65/Zn into milk of goats after oral and I.V. doses; the experiments are incomplete at this time. In controlled temperature studies it was found that 6.6 times as much radioiodine was secreted into milk when goats were at 33/sup 0/ as opposed to 5/sup 0/C. When radioiodine is put into the mammary gland the transfer from milk to body is rapid; more rapid than is the case for /sup 65/Zn. The analysis of these data indicate the need for a model capable of handling expansion of a compartment.

  5. Clinical evaluation of multidrug-resistance in lung cancers with dual-isotope 99Tcm-MIBI and 201Tl SPECT imaging

    International Nuclear Information System (INIS)

    Objective: Multidrug-resistance (MDR) may be a powerful impact on chemotherapy of lung cancers. In vivo detecting MDR of lung cancer using dual-isotope 99Tcm-methoxyisobutylisonitrile (MIBI) and 201Tl SPECT imaging was evaluated. Methods: Eighty patients with lung cancer underwent dual-isotope SPECT study before chemotherapy. Regions of interest (ROI) were placed over the tumors (T), contralateral normal lung tissue (N) and heart (H) on transverse view, and T/N uptake ratio, T/H uptake ratio, clearance rate and retention index of both isotopes were calculated. These results were compared with the efficacy of the chemotherapy according to the following classification. Tumor regression greater than 50%, tumor regression greater than 30% and less than 50%, tumor regression less than 30% and tumor enlargement was recorded as partial and complete response (PR and CR), median response (MR), no response (NR) and progression (PQ), respectively. Results: 1) All parameters of 201Tl were of no significant relationship with the efficacy of chemotherapy. 2) The parameters of 99Tcm -MIBI uptake ratio, 99Tcm-MIBI clearance rate and 99Tcm-MIBI retention index with heart as background were superior to that with contralateral normal lung tissue as background. The values of 99Tcm-MIBI retention index were 0.24 +- 0.08, 0.20 +- 0.11, 0.16 +- 0.08, 0.14 +- 0.05 in CR, MR, NR, PQ, respectively. 3) When 99Tcm -MIBI clearance rate >20% was used as positive threshold, the positive and negative predictive values for NR and PQ were 71.2% and 64.3%, respectively. And when 99Tcm-MIBI retention index 99Tcm-MIBI SPECT imaging is a useful method for in vivo detection of MDR of lung cancers

  6. Effect of beta blockade on single photon emission computed tomographic (SPECT) thallium-201 images in patients with coronary disease

    International Nuclear Information System (INIS)

    We evaluated the effect of beta blockers on thallium-201 (Tl-201) single photon emission computed tomographic (SPECT) imaging in 12 patients with coronary disease using an automated computer algorithm. Maximal exercise heart rate and blood pressure were reduced and exercise time was increased with beta blockers. Estimated stress defect size decreased from 47 +/- 36.3 gm during placebo treatment to 32 +/- 27.1 gm during beta blocker therapy (-32%; p less than 0.01). The placebo treatment redistribution defect was estimated to be 28 +/- 29.8 gm. It fell to 15 +/- 23.3 gm with beta blockade (-46%; p less than 0.005). All patients had a stress Tl-201 defect during placebo treatment and eight had redistribution defects consistent with residual scar. During beta blocker therapy, 2 of 12 patients had normal stress-redistribution studies and only five patients had redistribution defects. Beta blockade can reduce exercise and redistribution Tl-201 SPECT defect size significantly while simultaneously increasing exercise time and reducing angina. Beta blockers may unmask or may eliminate evidence of redistribution. Tl-201 SPECT imaging may be useful in defining the reduction in ischemia produced by cardiac drugs

  7. Effect of beta blockade on single photon emission computed tomographic (SPECT) thallium-201 images in patients with coronary disease

    Energy Technology Data Exchange (ETDEWEB)

    Narahara, K.A.; Thompson, C.J.; Hazen, J.F.; Brizendine, M.; Mena, I.

    1989-05-01

    We evaluated the effect of beta blockers on thallium-201 (Tl-201) single photon emission computed tomographic (SPECT) imaging in 12 patients with coronary disease using an automated computer algorithm. Maximal exercise heart rate and blood pressure were reduced and exercise time was increased with beta blockers. Estimated stress defect size decreased from 47 +/- 36.3 gm during placebo treatment to 32 +/- 27.1 gm during beta blocker therapy (-32%; p less than 0.01). The placebo treatment redistribution defect was estimated to be 28 +/- 29.8 gm. It fell to 15 +/- 23.3 gm with beta blockade (-46%; p less than 0.005). All patients had a stress Tl-201 defect during placebo treatment and eight had redistribution defects consistent with residual scar. During beta blocker therapy, 2 of 12 patients had normal stress-redistribution studies and only five patients had redistribution defects. Beta blockade can reduce exercise and redistribution Tl-201 SPECT defect size significantly while simultaneously increasing exercise time and reducing angina. Beta blockers may unmask or may eliminate evidence of redistribution. Tl-201 SPECT imaging may be useful in defining the reduction in ischemia produced by cardiac drugs.

  8. Purification of single-photon entanglement.

    Science.gov (United States)

    Salart, D; Landry, O; Sangouard, N; Gisin, N; Herrmann, H; Sanguinetti, B; Simon, C; Sohler, W; Thew, R T; Thomas, A; Zbinden, H

    2010-05-01

    Single-photon entanglement is a simple form of entanglement that exists between two spatial modes sharing a single photon. Despite its elementary form, it provides a resource as useful as polarization-entangled photons and it can be used for quantum teleportation and entanglement swapping operations. Here, we report the first experiment where single-photon entanglement is purified with a simple linear-optics based protocol. In addition to its conceptual interest, this result might find applications in long distance quantum communication based on quantum repeaters. PMID:20482160

  9. Effect of long-term exercise training on regional myocardial perfusion changes in patients with coronary artery disease

    International Nuclear Information System (INIS)

    The effect of long-term exercise training on myocardial perfusion in coronary artery disease (CAD) patients was assessed using 201Tl exercise studies at a baseline (4 months after the onset of CAD) and at a 1-year or more follow-up in 58 patients with stable CAD. The subjects had been divided into a training group (n=35) participating in supervised exercise 2 times per week for the follow-up period, and the control group (n=23). There was an improvement in the myocardial perfusion on stress 201Tl scintigraphy in 20 of the 35 (57.1%) trained patients and in 3 of the 23 (13.0%) of the control patients. The number of 201Tl stress myocardial perfusion defect segments was significantly decreased after the cardiac rehabilitation training (231 to 153 segments), but showed no change in the control group (158 to 156 segments). In spite of no significant differences in the number of involved coronary arteries, it improved (12/17 patients: 70.6%) more in the patients who had trained for more than 2 years compared to the patients who had trained for less than 2 years. The exercise tolerance increased in 25 of the 35 training group patients (71.4%), and in only 3 of the 23 control group patients (13.0%). The peak double products increased from 20,131±6,010 to 28,370±5,600 in the training group, and showed no change in the control group (20,567±5,112 to 20,964±7,728). The results indicated that the long-term physical training increased exercise tolerance and the double products of CAD patients. In addition, the training resulted in improved cardiac perfusion as evidenced by 201Tl scintigraphy. The findings suggest that exercise training is an advisable and effective treatment for patients with CAD. (K.H.)

  10. Detection of myocardial viability by means of Single Proton Emission Computed Tomography (Perfused SPECT) dual {sup 201} Tl (rest of 15 minutes, 24 late hours and 24 hours reinjection) and gated-SPECT {sup 99m} Tc-SESTAMIBI in effort or stimulation of the coronary reserves; Deteccion de viabilidad miocardica mediante tomografia por emision de foton unico (SPECT perfusorio) dual {sup 201} Talio (Reposo de 15 minutos, 24 horas tardio y 24 horas reinyeccion) y gated-SPECT {sup 99m} Tc-SESTAMIBI en esfuerzo o estimulo de reserva coronaria

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza V, R

    2004-07-01

    The objective of this work was to determine if the images of SPECT {sup 201} TI in rest of 15 minutes, 24 late hours and Gated-SPECT {sup 99m} Tc-SESTAMIBI in effort or stimulation of coronary reservation correlate with the study of 24 hours post reinjection of {sup 201}TI to determine the presence of having knitted viable myocardium. Material and methods: 29 patients were studied with coronary arterial illness (EAC) to who are carried out SPECT {sup 201} TI in rest with images of 15 minutes, 24 late hours and 24 hours reinjection, by means of the administration of {sup 201}TI to dose of 130 MBq and reinjection with 37 MBq. and Gated-SPECT {sup 99m}Tc-SESTAMIBI in effort or stimulation of coronary reservation, later to the administration of 1110 MBq. Results: 29 patients were included according to inclusion approaches and exclusion, of those which 22 (75.86%) they correspond at the masculine sex and 7 (24.13%) to the feminine one, with an average of 62.1 year-old age, 2320 segments myocardial were analysed so much it is phase post-effort as rest; they were diagnosed a total of 264 segments with heart attack, of which viability myocardium was observed in 174 segments. The statistical tests are analysis of frequencies. The non parametric test of Wilcoxon and Mann-Whitney. Conclusions: the viability myocardial at the 24 late hours and 24 hours reinjection was similar; significant difference exists between the study of 15 minutes and 24 hours reinjection, ischemic illness was also demonstrated in territories different to the heart attack area in the studies of 15 minutes, late 24 hours and 24 hours reinjection. (Author)

  11. Single photon emission computed tomography

    International Nuclear Information System (INIS)

    Exercise Tl-201 myocardial perfusion imaging has been widely used as a noninvasive technique for the identification and evaluation of patients with known or suspected coronary artery disease (CAD). However, planar Tl-201 imaging with visual analysis has been more successful in detecting the presence of coronary artery disease than it has in identifying the specific coronary arteries involved or the extent of disease. Furthermore, visual analysis of Tl-201 images is subject to marked observer variability. However, performance of planar imaging can be improved using quantitative Tl-201 analysis. The authors discuss how they have recently utilized both rotational Tl-201 tomography and quantification to develop and validate a new technique using polar coordinate maps to display regional uptake and redistribution of Tl-201

  12. Cavity-based single-photon sources

    OpenAIRE

    Kuhn, A; Ljunggren, D

    2010-01-01

    We introduce the basic concepts and characteristic properties of single-photon emitters based on resonator effects in optical cavities, and provide a review of the most prominent implementations. First we discuss the elementary principles of cavity quantum electrodynamics, which determine how single quantum systems couple to the quantised field modes of optical resonators, and then show how to exploit these principles in order to generate single photons on demand. Furthermore, we elucidate ho...

  13. Stable single photon source in near infrared

    OpenAIRE

    Gaebel, T.; Popa, I; Gruber, A; Domhan, M.; Jelezko, F; Wrachtrup, J.

    2004-01-01

    Owing to their unsurpassed photostability, defects in solids may be ideal candidates for single photon sources. Here we report on generation of single photons by optical excitation of a yet unexplored defect in diamond, the nickel-nitrogen complex (NE8) centre. The most striking feature of the defect is its emission bandwidth of 1.2 nm at room temperature. The emission wavelength of the defect is around 800 nm, which is suitable for telecom fibres. In addition, in this spect...

  14. Clinical study on the time courses of serum myosin light chain I levels in patients with acute myocardial infarction

    International Nuclear Information System (INIS)

    Changes of serum myosin light chain I (Myosin LCI) concentrations and creatine kinase (CK) activities were serially measured in 23 patients with acute myocardial infarction. Intracoronary thrombolysis was performed in 14 patients (ICT group) while the remaining 9 patients were treated in the conventional manner (non ICT group). The relationships between the maximum levels of serum Myosin LCI or CK and a myocardial infarct size index or left ventricular function were evaluated in 18 patients. The myocardial infarct size index was determined by 201Tl myocardial scintigrams performed in the chronic phase. Multiple peaks of Myosin LCI were observed in 64% (9/14) of the ICT group and the first peak in 6 of these patients appeared much earlier in the same time as CK peak than in the non-ICT group, while multiple peaks were seen only in one case in the non-ICT group. The infarct size index by 201Tl myocardial SPECT correlated with maximum Myosin LCI levels (r=0.88, p<0.001, n=10) and CK activities (r=0.67, p<0.05, n=10). These results indicate that the measurement of serum Myosin LCI is very useful for estimating the extent of myocardial damage and suggest that myocardial degeneration occurs at a very early phase of myocardial infarction. (author)

  15. Prognostic value of normal myocardial perfusion images using technetium-99m based compounds

    International Nuclear Information System (INIS)

    Full text: The prognostic value of 201Tl myocardial perfusion imaging is well established. The purpose of this study was to describe the clinical outcome of patients with known or suspected ischemic heart disease and a normal myocardial perfusion scan using 99mTc labelled agents (Sestamibi/Tetrofosmin). Fifty-three patients (29 males, 24 females, mean age 51.58 years) with known or suspected coronary artery disease (CAD) were stressed (3 with dipyridamole and 50 with bicycle ergometer) and gated SPECT myocardial perfusion scan obtained with triple head gamma camera. All patients had normal myocardial perfusion and wall motion. Patients were followed up for 21-24 months and follow up data was obtained from telephone interview. Cardiac events were defined as, hard events (myocardial infarct, unstable angina, death) or soft events (angioplasty or other revascularization). ST segment depression occurred in 11 (20.75%), 6 (11.32%) had pre-test angiographically significant CAD, 4 (7.55%) were studied post CABG and 3 (5.6%) patients had a normal post scan angiography. Cardiac events occurred in none of the patients. Our study confirms the benign outcome of patients with normal myocardial perfusion scan using 99mTc labelled agents, even in patients with angiographically significant CAD, consistent with prior observation for 201Tl cardiac imaging. The lesser number of patients who underwent coronary angiography following a normal perfusion scan shows the determination by treating physicians, that no further evaluation was necessary

  16. Assessment of acute myocardial necrosis after cardiopulmonary resuscitation and cardioversion by means of combined thallium-201/technetium-99m pyrophosphate tomography

    International Nuclear Information System (INIS)

    Simultaneous thallium-201/technetium-99m pyrophosphate (PYP) tomography was prospectively applied to 57 patients without typical clinical or electrocardiographic signs of acute myocardial infarction within 48 h after successful resuscitation from out-of-hospital cardiac arrest. Scintigraphic evidence of acute necrosis was present in 23/57 patients (40%). Increased 99mTc-PYP uptake in the pericardial tissue was found in 24 patients (42%). Maximal creatine kinase (CK) concentration was increased in 50/57 patients (88%). CK-MB activity averaged 68 ± 52 U/l in patients with positive and 17 ± 13 U/l in patients with negative tomograms (P 201Tl/99mTc-PYP tomography. It may be concluded that simultaneous 201Tl/99mTc-PYP tomography is a valuable tool for evaluation of myocardial necrosis after cardiopulmonary resuscitation including DC countershock. Acute myocardial necrosis, as indicated by scintigraphy, represents a potential trigger for the occurrence of ventricular fibrillation. Therefore, 201Tl/99mTc-PYP tomography can be recommended in order to guide further diagnostic and therapeutic interventions in patients after cardiopulmonary resuscitation in whom the underlying cause of the occurrence of ventricular fibrillation is obscure. (orig./MG)

  17. Validation of a short-scan-time imaging protocol for thallium-201 myocardial SPECT with a multifocal collimator

    International Nuclear Information System (INIS)

    IQ-SPECT (Siemens AG, Munich, Germany) is a highly sensitive single-photon-emission computed tomography (SPECT) myocardial perfusion imaging (MPI) system that uses a multifocal collimator. We searched for a suitable protocol for short-time imaging by IQ-SPECT in thallium-201 (Tl-201) MPI by evaluating phantom images and also by comparing human IQ-SPECT images with conventional SPECT images as reference standards. We assessed the image quality using the normalized mean square error (NMSE) and drew up count profiles in Tl-201 SPECT images acquired with IQ-SPECT in a phantom study. We also performed Tl-201 stress myocardial SPECT/CT in 21 patients and compared delayed images acquired by using IQ-SPECT with 36 or 17 views per head with images obtained by using conventional SPECT. The NMSE of SPECT images from IQ-SPECT with 36 views was approximately one-fifth of that with 17 views. The myocardial count profile of images with 17 views was lower than those of images with 36 or 104 views in some regions. Defect scores were significantly lower, and image quality scores higher, in images from conventional SPECT than in those from IQ-SPECT with 17 views. Defect scores and image quality scores were equivalent in images from conventional SPECT and those from IQ-SPECT with 36 views. Agreement with the results of conventional SPECT in terms of coronary artery territory-based defect judgment was the best in IQ-SPECT with 36 views with computed tomography-derived attenuation correction (CTAC): the kappa values for IQ-SPECT with 36 views were 0.76 (without CTAC) and 0.83 (with CTAC), and those for IQ-SPECT with 17 views were 0.62 (without CTAC) and 0.59 (with CTAC). The difference in quantitative tracer uptake between conventional SPECT images and IQ-SPECT images was significantly greater for IQ-SPECT images with 17 views than for those with 36 views. Scanning with 36 views per head with CTAC may be appropriate for Tl-201 MPI using IQ-SPECT, because it provides images equivalent to those using conventional SPECT. (author)

  18. Simple microcavity for single-photon generation.

    Science.gov (United States)

    Plakhotnik, Taras

    2005-04-18

    A new design of an optical resonator for generation of single-photon pulses is proposed. The resonator is made of a cylindrical or spherical piece of a polymer squeezed between two flat dielectric mirrors. The mode characteristics of this resonator are calculated numerically. The numerical analysis is backed by a physical explanation. The decay time and the mode volume of the fundamental mode are sufficient for achieving more than 96% probability of generating a single-photon in a single-mode. The corresponding requirement for the reflectivity of the mirrors (~99.9%) and the losses in the polymer (100 dB/m) are quite modest. The resonator is suitable for single-photon generation based on optical pumping of a single quantum system such as an organic molecule, a diamond nanocrystal, or a semiconductor quantum dot if they are imbedded in the polymer. PMID:19495201

  19. Stable single photon source in near infrared

    CERN Document Server

    Gaebel, T; Gruber, A; Domhan, M; Jelezko, F; Wrachtrup, J

    2004-01-01

    Owing to their unsurpassed photostability, defects in solids may be ideal candidates for single photon sources. Here we report on generation of single photons by optical excitation of a yet unexplored defect in diamond, the nickel-nitrogen complex (NE8) centre. The most striking feature of the defect is its emission bandwidth of 1.2 nm at room temperature. The emission wavelength of the defect is around 800 nm, which is suitable for telecom fibres. In addition, in this spectral region little background light from the diamond bulk material is detected. Consequently, a high contrast in antibunching measurements is achieved.

  20. Room temperature stable single-photon source

    OpenAIRE

    Beveratos, Alexios; Kuehn, Sergei; Brouri, Rosa; Gacoin, Thierry; Poizat, Jean-Philippe; Grangier, Philippe

    2001-01-01

    We report on the realization of a stable solid state room temperature source for single photons. It is based on the fluorescence of a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. Antibunching has been observed in the fluorescence light under both continuous and pulsed excitation. Our source delivers 2*10^4 single-photon pulses per second at an excitation repetition rate of 10 MHz. The number of two-photon pulses is reduced by a factor of five compared ...

  1. Clinical effectiveness of {sup 99m}Tc-MIBI in the evaluation of bone metastasis from primary lung cancer-comparative study with {sup 201}Tl

    Energy Technology Data Exchange (ETDEWEB)

    Nagamachi, Shigeki; Jinnouchi, Seishi; Nishii, Ryuichi; Flores, L.G. II; Nakahara, Hiroshi; Futami, Shigemi; Tamura, Shozo [Miyazaki Medical Coll., Kiyotake (Japan); Kawai, Keiichi

    1999-07-01

    We compared the diagnostic usefulness of {sup 99m} Tc-MIBI (MIBI) in detection of bone metastasis from lung cancer with {sup 201}Tl (Tl). The study group was composed of 36 primary lung cancer patients. Dual isotope scintigraphy was performed after intravenous infection of 600 MBq of MIBI and 111 MBq of Tl and visual analysis was made on the basis of the scintigraphic images. In the regional evaluation, spinal bone metastases were well visualized on MIBI scintigraphy (70%) while Tl detection was only 46%. In other regions, positive rates were under 30% with both radiopharmaceuticals. The positive rate was higher in MIBI than Tl (40.1% versus 25.0%). According to X-ray findings, 71.2% of lytic metastatic lesions were detected by MIBI. In contrast 47.8% of mixed metastatic lesions could be visualized by MIBI. Only 20.6% could be detected by MIBI in the lesions with normal X ray lesions. On the comparative study of clinical parameters between the MIBI positive group and the MIBI negative group, Alkali phosphatase was significantly higher in the MIBI positive group (317.9 versus 175.2). Histopathologically all large cell carcinomas and most small cell cancer was included in the MIBI positive group. (author)

  2. Clinical effectiveness of 99mTc-MIBI in the evaluation of bone metastasis from primary lung cancer-comparative study with 201Tl

    International Nuclear Information System (INIS)

    We compared the diagnostic usefulness of 99m Tc-MIBI (MIBI) in detection of bone metastasis from lung cancer with 201Tl (Tl). The study group was composed of 36 primary lung cancer patients. Dual isotope scintigraphy was performed after intravenous infection of 600 MBq of MIBI and 111 MBq of Tl and visual analysis was made on the basis of the scintigraphic images. In the regional evaluation, spinal bone metastases were well visualized on MIBI scintigraphy (70%) while Tl detection was only 46%. In other regions, positive rates were under 30% with both radiopharmaceuticals. The positive rate was higher in MIBI than Tl (40.1% versus 25.0%). According to X-ray findings, 71.2% of lytic metastatic lesions were detected by MIBI. In contrast 47.8% of mixed metastatic lesions could be visualized by MIBI. Only 20.6% could be detected by MIBI in the lesions with normal X ray lesions. On the comparative study of clinical parameters between the MIBI positive group and the MIBI negative group, Alkali phosphatase was significantly higher in the MIBI positive group (317.9 versus 175.2). Histopathologically all large cell carcinomas and most small cell cancer was included in the MIBI positive group. (author)

  3. Usefulness of the 201TlCl exercise leg perfusion scintigraphy in arteriosclerosis obliterans (ASO). With evaluation of leg perfusion comparing before and after PTA

    International Nuclear Information System (INIS)

    Twenty-eight patients of arteriosclerosis obliterans (ASO) complaining of intermittent claudication or pain at rest underwent symptom limited exercise leg perfusion scintigraphy using 201TlCl (Tl). Regions of interest (ROI) were drawn around each buttocks, thighs, calves and feet in whole body image, and we calculated Lesion/Normal Index (LNI) which was the devided value of the average count per pixel of each ROI of the affected side by that of the normal side. The average LNI of the foot was 0.81 and was smaller than other regions (p<0.05). Other region except foot showed Tl high uptake in affected side in some cases. Fifteen patients were compared after percutaneous transluminal angioplasty (PTA) with before PTA, and LNI of the foot statistically improved after PTA (p<0.005). The period suffering from disease of the group of Tl hight uptake in the affected leg was statistically shorter than that of the group of Tl non-high uptake (p<0.05). We supposed that the Tl uptake of the foot reflects ischemia of the leg sensitively, and high uptake of Tl in affected leg is concerned with compensatory change of microcirculation of ischemic leg in subacute period. This scintigraphy was thought to be useful to detect the ASO and to evaluate the effect of PTA, and was able to avail diagnosis and observation of the course of ASO patient. (author)

  4. Feasibility of single photon tomography with RB-82

    International Nuclear Information System (INIS)

    Rb-82 (t 1/2 = 75 sec) is a positron emitting myocardial perfusion tracer available from a long lived (t 1/2 = 25d) Sr-82 generator. The authors have imaged Rb-82 in the single photon mode using a Pho-TV gamma camera with a parallel hole rotating tungsten collimator but only one view of the heart is obtained with each Rb-82 injection. For exercise studies with Rb-82, tomographic myocardial imaging is desirable. Because of the limited availability of ECT instrumentation, the clinical utilization of this tracer will be enhanced by the development of suitable instrumentation for imaging high energy photons in standard nuclear medicine units. A 7 pinhole collimator capable of imaging high energy photons was designed for an LFOV camera. It was built with thick shielding (2 1/2'' of lead) which largely preserved the geometry of the original system designed for low energy tracers and myocardial images obtained with N-13 ammonia were previously reported. Using 4mm pinhole inserts of tungsten, Rb-82 imaging was performed at rest in 4 male subjects after injection of tracer intravenously in doses up to 60 mCi. A commercially available software program for a DEC Gamma-11 which was designed to avoid exaggeration of lesions was used to reconstruct activity imaged from 2 - 7 minutes after injection. Tomographic sections of good quality were obtained. Sequential rest and exercise studies should be feasible with this technique of tomographic myocardial imaging. The short half life of the tracer also allows detection of changing patterns during the redistribution phase with serial injections after exercise

  5. Interactive Screen Experiments with Single Photons

    Science.gov (United States)

    Bronner, Patrick; Strunz, Andreas; Silberhorn, Christine; Meyn, Jan-Peter

    2009-01-01

    Single photons are used for fundamental quantum physics experiments as well as for applications. Originally being a topic of advance courses, such experiments are increasingly a subject of undergraduate courses. We provide interactive screen experiments (ISE) for supporting the work in a real laboratory, and for students who do not have access to…

  6. Single Photon Experiments and Quantum Complementarity

    Directory of Open Access Journals (Sweden)

    Georgiev D. D.

    2007-04-01

    Full Text Available Single photon experiments have been used as one of the most striking illustrations of the apparently nonclassical nature of the quantum world. In this review we examine the mathematical basis of the principle of complementarity and explain why the Englert-Greenberger duality relation is not violated in the configurations of Unruh and of Afshar.

  7. Cardiac sarcoidosis: Reversion of myocardial perfusion abnormalities by dipyridamole

    International Nuclear Information System (INIS)

    A thallium Tl 201 scan was performed on one young patient who met all of the criteria for the diagnosis sarcoidosis. A resting scan before treatment showed marked defects which were not resolved on the redistribution scan, thus leading to the diagnosis of cardiac sarcoidosis, which was also suspected from clinical signs. After dipyridamole infusion (0.142 mg/kg per minute over 4 min), his 201Tl scan was quite normal. Haemodynamic investigation showed a low coronary sinus blood flow with a low lactate extraction: these abnormalities were fully reversed by i.v. dipyridamole infusion. Afterwards, the patient was given oral dipyridamole (450 mg/day) over 4 weeks; at the end of this treatment, his resting 201Tl scan was quite normal. These results suggest that myocardial perfusion abnormalities in sarcoidosis may be reversible after pharmacological vasodilation. Thus, in order to assess cardiac sarcoidosis, a resting myocardial scan should be performed before a scan after dipyridamole infusion. These results may have clinical, pathophysiological and therapeutic implications with regard to cardiac sarcoidosis. (orig.)

  8. Myocardial scintigraphy with thallium-201 and technetium-99m-hexakis-methoxyisobutylisonitrile in left bundle branch block: a study in patients with and without coronary artery disease

    International Nuclear Information System (INIS)

    In left bundle branch block (LBBB) thallium-201 myocardial scintigraphy frequently reveals septal abnormalities in the absence of coronary artery disease (CAD) and gives rise to 'false-positive' results in patients with suspected CAD. It has not yet been clarified which pathophysiological mechanism is responsible for these perfusion abnormalities. A total of 66 patients with constant LBBB were investigated with 201Tl or technetium-99m-hexakis-methoxyisobutylisonitrile (MIBI), 62 underwent coronary angiography. Of 12 patients without left anterior descending artery (LAD) or right coronary artery (RCA) stenoses, 11 had a reversible septal activity deficit after 201Tl stress injection, whereas 20 of 22 patients without relevant CAD showed a constant stress/rest septal deficit using MIBI. Regarding patients with significant LAD and/or RCA stenoses, both radio-pharmaceuticals almost always showed a 'reversible' septal deficit: With 201Tl in 15 of 16 individuals and with MIBI in 14 of 15. In 12 patients 201Tl was reinjected at rest. In those who had LAD or RCA stenoses (n=5), early septal activity uptake after stress injection was poorer than that after rest injection; in the absence of CAD (n=7), septal stress uptake corresponded with that of rest injection. It is concluded that septal perfusion abnormalities in LBBB and the absence of CAD are characterized by an exercise-independent reduction of septal blood flow per mass of viable myocardium and that stress/rest injection protocols of myocardial perfusion tracers are able to differentiate between LBBB with and without CAD. (orig.)

  9. Optimal positioning in the detection of inferior wall infarct size with myocardial perfusion scintigraphy: prone vs. supine

    Directory of Open Access Journals (Sweden)

    ?smail Do?an

    2010-12-01

    Full Text Available Objective: The prone position is commonly utilized to reduce false positive perfusion defects because this position overcomes the diaphragmatic inferior wall attenuation in single-photon emission computerized tomography (SPECT studies. We investigated whether the prone position had an important advantage over the supine position in determining the severity and extent of infarct in patients with acute inferior myocardial infarction (MI. Methods: Twenty-nine male patients (mean age 61±10 years with acute inferior MI were enrolled in the cross-sectional study. After injection of thallium-201 (201Tl under resting conditions, redistribution SPECT imaging was twicely performed in each subject, in both the supine and prone positions, consecutively. The extent and severity scores of the perfusion defects were calculated from the sum of individual segment scores. Myocardial infarction size was also evaluated using peak cardiac troponin T (cTnT levels. Wilcoxon rank and Spearman’s rank correlation tests were used for statistical analyses of data. Results: For the supine vs. prone positions, the median defect severity scores were 8 (4-13 vs. 5 (0.5-8.5 and the defect extent scores were 4 (3-5.5 vs. 3 (0.5-4.5, respectively. Both perfusion defect scores in the prone position were significantly lower than those in the supine position (p<0.001. The mean peak cTnT level during hospitalization was 7.2±3.9 ?g/l. Peak cTnT levels were correlated with all SPECT parameters. However, the correlation was greater in the prone position (defect severity: r=0.712, p<0.001 (defect extent: r=0.790, p<0.001 than in the supine position (defect severity: r=0.495, p<0.01 (defect extent: r=0.481, p<0.01. Conclusion: In patients with inferior MI, the SPECT results revealed a significant difference between the supine and prone images. The perfusion extent and severity scores of SPECT in the inferior wall with prone imaging correlates better with the peak troponin compared to the supine position. Comparative studies that use advanced imaging tools are needed to verify our present findings.

  10. Clinical significance of thallium-201 myocardial scintigraphy for the estimation of natural course in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    The present study estimated the natural course of hypertrophic cardiomyopathy (HCM) using thallium-201 (Tl) myocardial scintigraphy. Tl single photon emission computed tomography (SPECT) was performed once every six months for at least two years in 17 HCM patients. According to the changes in short axial tomograms between the first and the last SPECT, patients with HCM were divided into 3 groups: 1) increased group: Tl uptake increased more than 16% in at least one quarter of the total area of short axial tomograms during the follow-up period, 2) decreased group: Tl uptake decreased more than 16% in at least quarter of the total area of short axial tomograms and that Tl uptake in the decreased area was less than 52% of maximal Tl uptake, and 3) no change group: Tl uptake neither increased nor decreased. The total 12-lead QRS amplitude on electrocardiograms, and left ventricular end-diastolic and end-systolic dimensions (LVDd and LVDs) on M-mode echocardiograms between the initial and the latest recordings were also measured. The mean follow-up period was 34.4±18.6 months in Tl-SPECT, 71.4±25.5 months in EEG and 64.0±26.5 months in echocardiogram. Four patients with HCM (23.5%) belonged to the increased group, 9 patients (53%) to the decreased group and 4 patients (23.5%) to the no change group. The total QRS amplitude in decreased group significantly decreased from 29.1±9.8 mV to 22.8±6.5 mV (P<0.01), but in non-decreased group there was no significant change. The LVDd and LVDs levels in the decreased group significantly increased from 37.4±3.6 mm to 44.1±4.7 mm (P<0.01), and from 20.3±4.3 mm to 26.3±3.8 mm (P<0.05), respectively; but those in non-decreased group showed no significant change. These findings suggest that in the natural course of HCM, chronic myocardial damages are observed in more than 50% HCM patients; this process seems closely related to the progression from HCM into dilated cardiomyopathy-like features. (author)

  11. 131I, 99mTc, 67Ga, 201Tl: evaluation of dose calibrators in nuclear medicine services of Porto Alegre City over a period of 5 years

    International Nuclear Information System (INIS)

    A programme for the comparison of activity measurements of radionuclides, administered to patients in Nuclear Medicine Services with the purpose of diagnosis or therapy, is being conducted under the coordination of the Radioprotection and Dosimetry Institute of the Brazilian Nuclear Energy Commission. All Nuclear Medicine Services in Brazil are required to employ dose calibrators, also known as activity meters, to measure the activity of solutions containing radionuclides prior to the administration of these radiopharmaceuticals to patients for the purpose of either diagnosis or treatment of illnesses. It is important, however, to measure with accuracy the activity of the administered radiopharmaceuticals to ensure images with the desired quality without submitting patients to unnecessary or insufficient radiation exposures. In the present work, measurements of the activity of samples of 131I, 99mTc, 67Ga and 201Tl, employing 5 ml radioactive samples in penicillin flasks, were conducted in the dose calibrators of the Nuclear Medicine Services of the city of Porto Alegre, from 2004 until 2008. The performance of the dose calibrators was evaluated by means of the Ratio R, obtained by dividing the mean value of the measurements obtained in each Nuclear Medicine Services, by the mean reference value measured for each of the radioactive samples in an activity meter previously calibrated by Radioprotection and Dosimetry Institute. Values of R between 0,90 and 1,10 are considered to be in accordance with the requirements specified in the Brazilian Regulation. The results were analysed to evaluate the compliance with the applicable regulation and were also compared to data available in the literature and obtained in other Brazilian cities and regions. The performance of the activity meters in Porto Alegre is shown to be very good, which contributes to ensure the radiological protection of patients submitted to diagnosis or therapy with radiopharmaceuticals. (author)

  12. Optimized Heralding Schemes for Single Photons

    CERN Document Server

    Huang, Yu-Ping; Kumar, Prem

    2011-01-01

    A major obstacle to a practical, heralded source of single photons is the fundamental trade-off between high heralding efficiency and high production rate. To overcome this difficulty, we propose applying sequential spectral and temporal filtering on the signal photons before they are detected for heralding. Based on a multimode theory that takes into account the effect of simultaneous multiple photon-pair emission, we find that these filters can be optimized to yield both a high heralding efficiency and a high production rate. While the optimization conditions vary depending on the underlying photon-pair spectral correlations, all correlation profiles can lead to similarly high performance levels when optimized filters are employed. This suggests that a better strategy for improving the performance of heralded single-photon sources is to adopt an appropriate measurement scheme for the signal photons, rather than tailoring the properties of the photon-pair generation medium.

  13. Optimized heralding schemes for single photons

    International Nuclear Information System (INIS)

    A major obstacle to a practical, heralded source of single photons is the fundamental trade-off between high purity and high production rate. To overcome this difficulty, we propose applying sequential spectral and temporal filtering on the signal photons before they are detected for heralding. Based on a multimode theory that takes into account the effect of simultaneous multiple photon-pair emission, we find that these filters can be optimized to yield both high purity and a high production rate. While the optimization conditions vary depending on the underlying photon-pair spectral correlations, all correlation profiles can lead to similarly high performance levels when optimized filters are employed. This suggests that a better strategy for improving the performance of heralded single-photon sources is to adopt an appropriate measurement scheme for the signal photons, rather than tailoring the properties of the photon-pair generation medium.

  14. Advantages of gated silicon single photon detectors

    Science.gov (United States)

    Legré, Matthieu; Lunghi, Tommaso; Stucki, Damien; Zbinden, Hugo

    2013-05-01

    We present gated silicon single photon detectors based on two commercially available avalanche photodiodes (APDs) and one customised APD from ID Quantique SA. This customised APD is used in a commercially available device called id110. A brief comparison of the two commercial APDs is presented. Then, the charge persistence effect of all of those detectors that occurs just after a strong illumination is shown and discussed.

  15. Single photon double ionization of helium

    International Nuclear Information System (INIS)

    we have calculated the single photon double ionization cross section of helium using the fully correlated wave function for the ground state and partially correlated wave function for the final state. Our present theoretical investigation demonstrates that the inclusion of the full correlation in the initial as well as the final state wave function is indispensable in order to obtain reliable results in the close vicinity of the threshold. (author). 56 refs, 1 fig

  16. A Diamond Nanowire Single Photon Antenna

    OpenAIRE

    Babinec, Tom; Hausmann, Birgit J. M.; Khan, Mughees; Zhang, Yinan; Maze, Jero; Hemmer, Philip R.; Loncar, Marko

    2009-01-01

    The development of a robust light source that emits one photon at a time is an outstanding challenge in quantum science and technology. Here, at the transition from many to single photon optical communication systems, fully quantum mechanical effects may be utilized to achieve new capabilities, most notably perfectly secure communication via quantum cryptography. Practical implementations place stringent requirements on the device properties, including stable photon generati...

  17. Single-photon imaging in CMOS:

    OpenAIRE

    Charbon, Edoardo

    2010-01-01

    We report on the architectural design and fabrication of medium and large arrays of single-photon avalanche diodes (SPADs) for a variety of applications in physics, medicine, and the life sciences. Due to dynamic nature of SPADs, designs featuring a large number of SPADs require careful analysis of the target application for an optimal use of silicon real estate and of limited readout bandwidth. This paper describes the main trade-offs involved in architecting such chips and the solutions ado...

  18. Angle sensitive single photon avalanche diode

    International Nuclear Information System (INIS)

    An ideal light sensor would provide exact information on intensity, timing, location, and angle of incoming photons. Single photon avalanche diodes (SPADs) provide such desired high (single photon) sensitivity with precise time information and can be implemented at a pixel-scale to form an array to extract spatial information. Furthermore, recent work has demonstrated photodiode-based structures (combined with micro-lenses or diffraction gratings) that are capable of encoding both spatial and angular information of incident light. In this letter, we describe the implementation of such a grating structure on SPADs to realize a pixel-scale angle-sensitive single photon avalanche diode (A-SPAD) built in a standard CMOS process. While the underlying SPAD structure provides high sensitivity, the time information of the two layers of diffraction gratings above offers angle-sensitivity. Such a unique combination of SPAD and diffraction gratings expands the sensing dimensions to pave a path towards lens-less 3-D imaging and light-field time-of-flight imaging

  19. Angle sensitive single photon avalanche diode

    Science.gov (United States)

    Lee, Changhyuk; Johnson, Ben; Molnar, Alyosha

    2015-06-01

    An ideal light sensor would provide exact information on intensity, timing, location, and angle of incoming photons. Single photon avalanche diodes (SPADs) provide such desired high (single photon) sensitivity with precise time information and can be implemented at a pixel-scale to form an array to extract spatial information. Furthermore, recent work has demonstrated photodiode-based structures (combined with micro-lenses or diffraction gratings) that are capable of encoding both spatial and angular information of incident light. In this letter, we describe the implementation of such a grating structure on SPADs to realize a pixel-scale angle-sensitive single photon avalanche diode (A-SPAD) built in a standard CMOS process. While the underlying SPAD structure provides high sensitivity, the time information of the two layers of diffraction gratings above offers angle-sensitivity. Such a unique combination of SPAD and diffraction gratings expands the sensing dimensions to pave a path towards lens-less 3-D imaging and light-field time-of-flight imaging.

  20. Imaging of brain tumors in AIDS patients by means of dual-isotope thallium-201 and technetium-99m sestamibi single-photon emission tomography

    International Nuclear Information System (INIS)

    Our aim was to evaluate the use of dual-isotope thallium-201 (Tl) and technetium-99m sestamibi (sestamibi) simultaneous acquisition in brain single-photon emission tomography (SPET) for the differentiation between brain lymphoma and benign central nervous system (CNS) lesions in AIDS patients. Thirty-six consecutive patients with enhancing mass lesions on magnetic resonance (MR) imaging were included in the study. SPET of the brain was performed to obtain simultaneous Tl and sestamibi images. Regions-of-interest were drawn around the lesion and on the contralateral side to calculate uptake ratios. The final diagnosis was reached by pathologic findings in 17 patients and clinical and/or MR follow-up in 19 patients. Of the 36 patients, 11 had brain lymphoma, 1 glioblastoma multiforme, 15 toxoplasmosis and 9 other benign CNS lesions. Correlation between SPET and the final diagnosis revealed in 10 true-positive, 23 true-negative, 1 false-positive and 2 false-negative studies. All patients with toxoplasmosis had negative scans. A patient with a purulent infection had positive scans. Tl and sestamibi scans were concordant in every lesion. The same lesions that took up Tl were also visualized with sestamibi. However, sestamibi scans showed higher lesion-to-normal tissue uptake ratios (3.7±1.8) compared with those of Tl (2.3±0.8, P<0.002). Simultaneous acquisition of Tl and sestamibi can help differentiate CNS lymphoma from benign brain lesions in AIDS patients. (orig.)

  1. Tumour-like thallium-201 accumulation in brain infarcts, an unexpected finding on single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bernat, I. (Dept. of Neurology, Teaching Hospital of Semmelweis Univ. Medical School, Budapest (Hungary)); Toth, G. (Dept. of Neurology, Teaching Hospital of Semmelweis Univ. Medical School, Budapest (Hungary)); Kovacs, L. (Isotope Lab., Teaching Hospital of Semmelweis Univ. Medical School, Budapest (Hungary))

    1994-03-01

    In the present study our purpose was to investigate whether or not foci of [sup 201]Tl accumulation occur in reperfused areas with sustained morphological integrity indicated by computed tomography (CT) scans not showing hypodensity in the acute or sub-acute period. In 16 stroke patients with possible cortical embolic infarction, dual [sup 201]Tl and technetium-99m hexamethylpropylene amine oxime ([sup 99m]Tc-HMPAO) SPET was performed in both the acute and the subacute period. [sup 99m]Tc-HMPAO SPET was performed to detect reperfusion. Follow-up CT scans from the same period were also available. In five cases [sup 99m]Tc-HMPAO SPET ruled out reperfusion and [sup 201]Tl SPET was also negative. In four cases [sup 99m]Tc-HMPAO studies indicated reperfusion early in the acute phase (24-72 h), and comparative CT, without showing hypodensity in the acute or subacute period, also favoured the possibility of sustained metabolic activity. In these cases [sup 201]Tl SPET was negative in both the acute and the subacute period. In seven cases CT already showed necrosis in [sup 99m]Tc-HMPAO hypoperfused areas in the acute period, with negative results on corresponding [sup 201]Tl SPET. Later reperfusion occurred in the subacute period (8-14 days) as indicated by [sup 99m]Tc-HMPAO SPET, at which time an unexpected focal accumulation of [sup 201]Tl was detected. (orig./MG)

  2. Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

    International Nuclear Information System (INIS)

    The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving 201Tl (n = 120) or 99mTc-sestamibi injected at low dose at stress (99mTc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress (99mTc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, 201Tl 92 %, 99mTc-Low 86 %, 99mTc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p 201Tl or 99mTc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 ± 101 kcounts) and dramatically enhanced with CZT SPECT (+279 ± 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

  3. Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

    Energy Technology Data Exchange (ETDEWEB)

    Verger, Antoine; Karcher, Gilles [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Djaballah, Wassila [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Fourquet, Nicolas [Clinique Pasteur, Toulouse (France); Rouzet, Francois; Le Guludec, Dominique [AP-HP, Hopital Bichat, Department of Nuclear Medicine, Paris (France); INSERM U 773 Inserm and Denis Diderot University, Paris (France); Koehl, Gregoire; Roch, Veronique [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Imbert, Laetitia [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Centre Alexis Vautrin, Department of Radiotherapy, Vandoeuvre (France); Poussier, Sylvain [INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Fay, Renaud [INSERM, Centre d' Investigation Clinique CIC-P 9501, Nancy (France); Marie, Pierre-Yves [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); INSERM U961, Nancy (France); Hopital de Brabois, CHU-Nancy, Medecine Nucleaire, Vandoeuvre-les-Nancy (France)

    2013-03-15

    The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving {sup 201}Tl (n = 120) or {sup 99m}Tc-sestamibi injected at low dose at stress ({sup 99m}Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ({sup 99m}Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, {sup 201}Tl 92 %, {sup 99m}Tc-Low 86 %, {sup 99m}Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the {sup 201}Tl or {sup 99m}Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 {+-} 101 kcounts) and dramatically enhanced with CZT SPECT (+279 {+-} 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

  4. Evaluation of myocardial scintigraphy for the primary care of acute myocardial infarction

    International Nuclear Information System (INIS)

    We have evaluated the usefulness of myocardial scintigraphy in the primary care of patients with chest pain attack by performing the scintiscan at the earliest possible periods after attack. Materials included 16 patients with chest pain admitted through emergency room being diagnosed as AMI (12 cases) or suspected of AMI on the basis of clinical findings and conventional examinations including ECG and serum enzyme levels. Of 12 patients with AMI 11 revealed abnormal accumulation of sup(99m)Tc-PYP and focal defects in 201Tl myocardial imaging. One case gave false negative results in both studies with sup(99m)Tc-PYP and 201TlCl. Early nuclear medicine examinations in one patient with suspected AMI revealed negative result. The patient was diagnosed later as acute pericarditis. Among 3 other patients with suspected AMI 2 showed positive and one showed negative results for AMI in scintigraphies. We believe that the nuclear medicine procedures definitely contributed to the early diagnosis of AMI in 3 patients as they provided useful informations that ECG and serum enzyme did not provide. In two patients extremely useful informations would have been obtained, if scintigrams had been performed earlier. In 9 patients scintigrams supported the diagnosis made by conventional examinations. In two patients scintigraphy gave inconsistent results with those obtained by conventional procedures. Myocardial imaging should prove useful in early differential diagnosis of chest pain patients, if the opportunity to perform the procedures increases, which is extremely limited at present because of legal restriction to the use of radioisotopes at bed side. (author)

  5. Decreased perfusion in myocardial region of normal donor artery secondary to collateral development

    International Nuclear Information System (INIS)

    Thirty-one patients suffering from single vessel exertional angina with collaterals (Group A) were evaluated by stress 201Tl myocardial emission CT (Tl-SPECT) with 16 controls of severely stenotic single vessel exertional angina without collaterals (Group B). Group A included 21 patients (68%) who showed an extensive perfusion defect in double artery myocardial regions, including the normal donor artery myocardial region (DMR). However, there were no such cases in Group B, giving a significant difference between these 2 groups (p < 0.001). Four patients in Group A, having a perfusion defect both in DMR and in the collateral dependent myocardial region (CMR) underwent a successful percutaneous transluminal coronary angioplasty (PTCA) with disappearance of collaterals. Tl-SPECT findings after PTCA showed no perfusion defect either in CMR or in DMR. This has been explained on the basis that the coronary collaterals stole blood and produced perfusion defect in DMR. (orig.)

  6. Factors affecting the myocardial activity acquired during exercise SPECT with a high-sensitivity cardiac CZT camera as compared with conventional Anger camera

    Energy Technology Data Exchange (ETDEWEB)

    Verger, Antoine; Karcher, Gilles [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947 and Universite de Lorraine, Nancy (France); Nancyclotep experimental imaging platform, Nancy (France); Imbert, Laetitia [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep experimental imaging platform, Nancy (France); Centre Alexis Vautrin, Department of Radiotherapy, Vandoeuvre (France); Yagdigul, Yalcine; Roch, Veronique [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep experimental imaging platform, Nancy (France); Fay, Renaud [INSERM, Centre d' Investigation Clinique CIC-P 9501, Nancy (France); Djaballah, Wassila [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947 and Universite de Lorraine, Nancy (France); Rouzet, Francois; Le Guludec, Dominique [AP-HP, Hopital Bichat, Department of Nuclear Medicine, Paris (France); INSERM U 773 and Denis Diderot University, Paris (France); Fourquet, Nicolas [Clinique Pasteur, Toulouse (France); Poussier, Sylvain [INSERM U947 and Universite de Lorraine, Nancy (France); Nancyclotep experimental imaging platform, Nancy (France); Marie, Pierre-Yves [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep experimental imaging platform, Nancy (France); INSERM U1116 and Universite de Lorraine, Nancy (France); CHU-Nancy, Allee du Morvan, Medecine Nucleaire, Hopital de Brabois, Vandoeuvre-les-Nancy (France)

    2014-03-15

    Injected doses are difficult to optimize for exercise SPECT since they depend on the myocardial fraction of injected activity (MFI) that is detected by the camera. The aim of this study was to analyse the factors affecting MFI determined using a cardiac CZT camera as compared with those determined using conventional Anger cameras. Factors affecting MFI were determined and compared in patients who had consecutive exercise SPECT acquisitions with {sup 201}Tl (84 patients) or {sup 99m}Tc-sestamibi (87 patients) with an Anger or a CZT camera. A predictive model was validated in a group of patients routinely referred for {sup 201}Tl (78 patients) or {sup 99m}Tc-sestamibi (80 patients) exercise CZT SPECT. The predictive model involved: (1) camera type, adjusted mean MFI being ninefold higher for CZT than for Anger SPECT, (2) tracer type, adjusted mean MFI being twofold higher for {sup 201}Tl than for {sup 99m}Tc-sestamibi, and (3) logarithm of body weight. The CZT SPECT model led to a +1 ± 26 % error in the prediction of the actual MFI from the validation group. The mean MFI values estimated for CZT SPECT were more than twofold higher in patients with a body weight of 60 kg than in patients with a body weight of 120 kg (15.9 and 6.8 ppm for {sup 99m}Tc-sestamibi and 30.5 and 13.1ppm for {sup 201}Tl, respectively), and for a 14-min acquisition of up to one million myocardial counts, the corresponding injected activities were only 80 and 186 MBq for {sup 99m}Tc-sestamibi and 39 and 91 MBq for {sup 201}Tl, respectively. Myocardial activities acquired during exercise CZT SPECT are strongly influenced by body weight and tracer type, and are dramatically higher than those obtained using an Anger camera, allowing very low-dose protocols to be planned, especially for {sup 99m}Tc-sestamibi and in non-obese subjects. (orig.)

  7. Statistical analysis of the temporal single-photon response of superconducting nanowire single photon detection

    CERN Document Server

    He, Y -H; Zhang, W -J; Zhang, L; Wu, J -J; Chen, S -J; You, L -X; Wang, Z

    2015-01-01

    Counting rate is a key parameter of superconducting nanowire single photon detectors (SNSPD) and is determined by the current recovery time of an SNSPD after a detection event. We propose a new method to study the transient detection efficiency (DE) and pulse amplitude during the current recovery process by statistically analyzing the single photon response of an SNSPD under photon illumination with a high repetition rate. The transient DE results match well with the DEs deduced from the static current dependence of DE combined with the waveform of a single-photon detection event. This proves that the static measurement results can be used to analyze the transient current recovery process after a detection event. The results are relevant for understanding the current recovery process of SNSPDs after a detection event and for determining the counting rate of SNSPDs.

  8. Experimental and clinical study of cardiac hypertrophy by thallium-201 myocardial scintigraphy

    International Nuclear Information System (INIS)

    I studied experimentally the myocardial uptake of 201Tl in cardiac hypertrophy in rat, and clinically evaluated cardiac shape and dimension in the patients with various types of cardiac hypertrophy. Experimentally, both myocardial blood flow (MBF) and Tl uptake were increased with cardiac weight. There were negative correlations between the extraction fraction and MBF. Tl uptake in Hypertrophy is not always dependent on MBF and affected by the altered metabolism of hypertrophied myocardium. Clinical study was performed in 29 normal subjects and in 90 patients with heart disease. The measurements of left ventricular (LV) size by Tl scintigraphy were well correlated with them by echocardiography. Aortic stenosis and hypertensive heart disease showed thick wall and spherical shape. Both mitral (MR) and aortic (AR) regurgitation showed ventricular dilatation, spherical shape (in chronic MR) and ellipsoid shape (in acute MR and in AR). Decreased ventricular size but normal shape was observed in mitral stenosis and cor pulmonale. Hypertrophic cardiomyopathy showed thick wall with asymmetric septal hypertrophy, while congestive cardiomyopathy showed thin wall with marked ventricular dilatation and spherical shape. I conclude that heart disease has characteristic figures in dimension and shape which may be reflecting cardiac performance or compensating for the load to the heart, and that 201Tl scintigraphy is useful evaluating cardiac morphology as well as in diagnosing myocardial ischemia. (J.P.N.)

  9. Clinical studies on the thallium-201 myocardial scintiphotography in patient with ischemic heart disease

    International Nuclear Information System (INIS)

    Thallium-201 myocardial scintiphotography was performed in 41 patients with myocardial infarction, 13 with angina pectoris and 12 without coronary artery disease. 1) In patients with congestive heart failure, blood clearance of 201Tl was delayed and radioactivity on the lung area increased compared with normal cases. 2) The scintillation camera image on a globular model containing 0.5 mCi of 201Tl was recorded in a magnetic disk as 64 * 64 matrix. Myocardial area was estimated as an area where the count showed more than 55% of maximum counts of myocardium. On the myocardial area, cold area due to infarction was defined as an area where the count showed less than 70% of the maximum. 3) The infarct size (%) was calculated as an ratio of the number of matrix in cold area against to myocardial area on the images of ANT, LAO, and LAT view. The mean infarct size (%) was larger in the patient with cardiomegaly (CTR >= 55%) than those without it, and it was larger in the patients with high values of serum CPK or LDH than in those with low values of them. 4) The correlation coefficient between the mean infarct size (%) and direction of QRS vector at the maximum, 20 msec and 40 msec were r = 0.780, 0.672 and 0.766, respectively. 5) Mean values of MBF/CO (%) ratio were showing significant low in myocardial infarction and in angina pectoris. 6) The mean value of Myocardial blood flow (MBF) was showing significant low in myocardial infarction and in angina pectoris. MBF (ml/min/m2) value expressed the states of coronary blood flow better than MBF/CO (%). (J.P.N.)

  10. Adsorption of {sup 99m}Tc, {sup 201}Tl and {sup 24}Na in soil of the Storage Center of Radioactive Wastes; Adsorcion de {sup 99m}Tc, {sup 201}Tl y {sup 24}Na en suelo del Centro de Almacenamiento de Desechos Radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez N, C. E. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, 52140 Metepec, Estado de Mexico (Mexico); Monroy G, F.; Anguiano A, J.; De la Cruz S, E., E-mail: estefany_rodriguezn@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (MX)

    2011-11-15

    One of the alternatives for the radioactive wastes disposition is to confine them in the soil, due to the ion retention properties that it has. The objective of this work is to determine the soil adsorption capacity (kD) coming from a cavity of the Storage Center of Radioactive Wastes for two cations (thallium and sodium) and an anion (technetium); with the purpose of knowing the retention capacity of this soil type. The distribution coefficients were determined to different particle sizes of the soil and solvent volume relationships: land mass. Three radioactive tracers were used: {sup 201}Tl{sup 3+}, {sup 24}Na and {sup 99m}TcO{sub 4}{sup -}. Additionally the organic matter contained in the soil was determined. The results indicate that the soil of this site not adsorb technetium (anion), while present a great affinity for sodium and thallium (cations). At the same time, it was found that the sodium distribution coefficient is affected by the particle size of the soil, observing that when the size is bigger, the adsorption is major. On the other hand, it was found that the land adsorb more quantity of Tl-201 when the relationship solvent volume: land mass is equal to 10000. The quantity of organic matter present in the soil is not a parameter that affects the soil capacity of adsorb sodium, however is necessary to carry out more specific studies to confirm this result. (Author)

  11. A search for single photons at PETRA

    International Nuclear Information System (INIS)

    A search for single photons, produced in e+e- collisions together with particles interacting only weakly with matter, has been performed using the CELLO detector operating at the PETRA storage ring. From the absence of any signal, an upper limit is set at 15 (90% CL) on the number of light neutrino species, and lower limits on various supersymmetric particle masses are derived. For massless photinos, mass degenerate scalar partners of the left- and right-handed electrons are excluded below 37.7 GeV/c2 (90% CL). (orig.)

  12. Comparison of an adaptive neuro-fuzzy inference system and an artificial neural network in the cross-talk correction of simultaneous 99 m Tc / 201Tl SPECT imaging using a GATE Monte-Carlo simulation

    Science.gov (United States)

    Heidary, Saeed; Setayeshi, Saeed; Ghannadi-Maragheh, Mohammad

    2014-09-01

    The aim of this study is to compare the adaptive neuro-fuzzy inference system (ANFIS) and the artificial neural network (ANN) to estimate the cross-talk contamination of 99 m Tc / 201 Tl image acquisition in the 201 Tl energy window (77 ± 15% keV). GATE (Geant4 Application in Emission and Tomography) is employed due to its ability to simulate multiple radioactive sources concurrently. Two kinds of phantoms, including two digital and one physical phantom, are used. In the real and the simulation studies, data acquisition is carried out using eight energy windows. The ANN and the ANFIS are prepared in MATLAB, and the GATE results are used as a training data set. Three indications are evaluated and compared. The ANFIS method yields better outcomes for two indications (Spearman's rank correlation coefficient and contrast) and the two phantom results in each category. The maximum image biasing, which is the third indication, is found to be 6% more than that for the ANN.

  13. VIZIBLE SPECTRUM SINGLE PHOTON DETECTION MODULE

    Directory of Open Access Journals (Sweden)

    ALEXANDRU RUSU

    2010-06-01

    Full Text Available Experiments using entangled photons and their applications require the detection of extremely weak light beams: the incoming photons arrive to the detector one at a time.Visible spectrum single photon detection is a challenging problem because the photon energy can produce only one electron-hole pair and such a signal is less than the sum of the intrinsic noise of the semiconductor detector and the associated electronics. Nevertheless, a free electron can initiate an avalanche discharge within an avalanche photodiode (APD, reversely polarized at a value slightly higher than its breakdown voltage. The discharge quenching and the restoration of the APD voltage are necessary to enable another photon detection.The module we are talking about is using both the passive quenching – to limit the discharge current to small enough values, considered safe – and the active quenching – to increase the upper margin of the measuring range to values as high as 1,… 1.5 mega pulses per second.Some major technical problems we have dealt with, to create a single photon detection module are presented:- APD equivalent dynamic resistor evaluation;- shielding against background light;- controlling the APD working temperature.A selected list of module measured characteristics concludes the presentation.

  14. Looking at single photons using hybrid detectors

    International Nuclear Information System (INIS)

    The SLS detector group develops silicon hybrid detectors for X-ray applications used in synchrotron facilities all over the world. Both microstrip and pixel detectors with either single photon counting or charge integrating read out are being developed. Low noise charge integrating detectors can be operated in single photon regime, i.e. with low fluxes and high frame rates in order to detect on average less than one photon per cluster of 2×2 pixels. In this case, the analog signal read out for each single X-ray provides information about the energy of the photon. Moreover the signal from neighboring channels can be correlated in order to overcome or even take advantage of charge sharing. The linear charge collection model describing microstrip detectors and large pixels is unsuitable for the calibration of small pitch pixel detectors due to the large amount of charge sharing occurring also in the corner region. For this reason, the linear charge collection model is extended to the case of small pixels and tested with monochromatic X-ray data acquired using the 25 ?m pitch MÖNCH and the 75 ?m pitch JUNGFRAU detectors. The successful outcome of the calibration of the MÖNCH detector is proven by the high energy resolution of the spectrum obtained by accumulating the counts from more than 6000 channels after the correction of the gain mismatches using the proposed model

  15. Reevaluation of the accuracy of exercise and dipyridamole thallium-201 myocardial SPECT for detecting myocardial ischemia

    International Nuclear Information System (INIS)

    To reevaluate the accuracy of stress thallium-201 (Tl) myocardial SPECT, 100 subjects with ischemic heart disease underwent coronary arteriography (CAG), left ventriculography (LVG) and 2 D-echocardiography (2D-ECHO) and were classified into 2 groups ; the patient group examined by Tl myocardial SPECT following intravenous administration of dipyridamole (DIP Tl-SPECT ; n=50), and another patient group studied by Tl myocardial SPECT using exercise testing with bicycle ergometer (EX Tl-SPECT ; n=50). Significant coronary lesions were defined as exceeding 75% luminal diameter narrowing in CAG with viable ventricular wall motion in LVG or 2D-ECHO. Although the sensitivity and specificity for detecting myocardial ischemia were 60.4% and 94.2% in DIP Tl-SPECT, and were 83.7% and 91.6% in EX Tl-SPECT. The sensitivity of Tl imaging in EX Tl-SPECT was significantly higher than that in DIP Tl-SPECT. In both two groups, the sensitivity for ischemic lesion of left anterior descending branch was higher than those of left circumflex branch and right coronary artery. The positive and negative predictive values were both about 80% in DIP Tl-SPECT and both about 90% in EX Tl-SPECT respectively. The sensitivity of EX Tl-SPECT for detecting myocardial ischemia is relatively higher than that of DIP Tl-SPECT, but DIP Tl-SPECT may provide a useful alternative test for potential coronary artery disease patients unable to perform the exercise testing. (author)

  16. Economical Quantum Secure Direct Communication Network with Single Photons

    OpenAIRE

    Deng, Fu-Guo; Li, Xi-Han; Li, Chun-Yan; Zhou, Ping; Zhou, Hong-yu

    2006-01-01

    A scheme for quantum secure direct communication (QSDC) network is proposed with a sequence of polarized single photons. The single photons are prepared originally in the same state |0> by the servers on the network, which will reduce the difficulty for the legitimate users to check eavesdropping largely. The users code the information on the single photons with two unitary operations which do not change their measuring bases. Some decoy photons, which are produced by operat...

  17. Single photon quantum erasing: a demonstration experiment

    International Nuclear Information System (INIS)

    In the conventional interpretation of quantum mechanics the interference of particles in a two-beam interferometer is closely related to the problem of which-way information. One of the mysteries of quantum mechanics relies on the assumption that the wavefunction of each photon propagates simultaneously along both classically allowed paths, and that interference arises as a consequence of the indistinguishability of those paths. Any attempt to obtain which-way information by putting individual labels on the photons in each pathway inevitably destroys interference. However, even in cases in which the photons carry which-way labels, it is possible to erase those labels after the particle has left the interferometer. The erasing process (partly or completely) destroys the which-way information, and thereby restores interference. This phenomenon is known as quantum erasing. Here we present a lecture demonstration experiment of quantum erasing based on a Mach-Zehnder interferometer operated with single photons.

  18. Single-Photon Superradiance in Cold Atoms

    CERN Document Server

    de Oliveira, Rafael A; Martins, Weliton S; Saldanha, Pablo L; Tabosa, José W R; Felinto, Daniel

    2014-01-01

    The interaction of an ensemble of atoms with common vacuum modes may lead to an enhanced emission into these modes. This phenomenon, known as superradiance, highlights the coherent nature of spontaneous emission, resulting in macroscopic entangled states in mundane situations. The complexity of the typical observations of superradiance, however, masks its quantum nature, allowing alternative classical interpretations. Here we stress how this picture changed with the implementation ten years ago of a new process for single-photon generation from atomic ensembles. We present then the last piece of evidence for the superradiant nature of such process, reporting the observation of an accelerated emission of the photon with a rate that may be tuned by controllably changing the number of atoms in the ensemble. Such investigation paves the way to a new, bottom-up approach to the study of superradiance.

  19. Cockroach optomotor responses below single photon level.

    Science.gov (United States)

    Honkanen, Anna; Takalo, Jouni; Heimonen, Kyösti; Vähäsöyrinki, Mikko; Weckström, Matti

    2014-12-01

    Reliable vision in dim light depends on the efficient capture of photons. Moreover, visually guided behaviour requires reliable signals from the photoreceptors to generate appropriate motor reactions. Here, we show that at behavioural low-light threshold, cockroach photoreceptors respond to moving gratings with single-photon absorption events known as 'quantum bumps' at or below the rate of 0.1 s(-1). By performing behavioural experiments and intracellular recordings from photoreceptors under identical stimulus conditions, we demonstrate that continuous modulation of the photoreceptor membrane potential is not necessary to elicit visually guided behaviour. The results indicate that in cockroach motion detection, massive temporal and spatial pooling takes place throughout the eye under dim conditions, involving currently unknown neural processing algorithms. The extremely high night-vision capability of the cockroach visual system provides a roadmap for bio-mimetic imaging design. PMID:25472974

  20. Noiseless Conditional Teleportation of a Single Photon.

    Science.gov (United States)

    Fuwa, Maria; Toba, Shunsuke; Takeda, Shuntaro; Marek, Petr; Mišta, Ladislav; Filip, Radim; van Loock, Peter; Yoshikawa, Jun-Ichi; Furusawa, Akira

    2014-11-28

    We experimentally demonstrate the noiseless teleportation of a single photon by conditioning on quadrature Bell measurement results near the origin in phase space and thereby circumventing the photon loss that otherwise occurs even in optimal gain-tuned continuous-variable quantum teleportation. In general, thanks to this loss suppression, the noiseless conditional teleportation can preserve the negativity of the Wigner function for an arbitrary pure input state and an arbitrary pure entangled resource state. In our experiment, the positive value of the Wigner function at the origin for the unconditional output state, W(0,0)=0.015±0.001, becomes clearly negative after conditioning, W(0,0)=-0.025±0.005, illustrating the advantage of noiseless conditional teleportation. PMID:25494071

  1. Circuit electromechanics with single photon strong coupling

    Science.gov (United States)

    Xue, Zheng-Yuan; Yang, Li-Na; Zhou, Jian

    2015-07-01

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  2. Thallium-201 myocardial imaging in children with heart disease

    International Nuclear Information System (INIS)

    201-TlCl myocardial imaging studies were performed to evaluate systolic pressure of right ventricle on 107 patients including 89 patients with congenital cardiac disease, patients with primary pulmonary hypertension and 13 patients with history of MCLS with the age range of 2 months to 17 years. The congenital cardiac disease group included 30 patients with tetralogy of Fallot, 8 patients with pulmonary stenosis (included 1 patient with double chambered right ventricle), 20 patients with ventricular septal defect, 10 patients with patent ductus arteriosus, 9 patients with atrial septal defect and 12 patients with complete transposition of greate arteries. None of the patients with history of MCLS had coronary involvement. 50 ?Ci/kg of 201-TlCl was infused intravenously and after 15 minutes the images were obtained from 5 directions (anterior, LAO 30, LAO 45, LAO 60 and lateral). The angle was determined to demonstrate the intraventricular septum and ventricular free walls cleary separated. The image of end-diastolic phase was obtained with ECG syncronized gated method from that direction. The ROI (region of interest) was defined as a slice line by drawing two lines perpendicular to the septum and the counts of the left and right ventricular free wall (Cl and Cr) were analized to evaluate the pressure of right ventricle. The pressure of ventricles were obtained by cardiac catheterization performed at the same time with myocardial imaging. The ratio of Cl and Cr (Cr/Cl) had good correlation with the ratio of peak systolic pressure of left ventricle and right ventricle (regression equation Y=0.84X+0.08, r=0.87). In each congenital heart disease group, very good corelation was also demonstrated (Y=1.46X-0.30, r=0.96 in PS ; Y=0.70X0.20, r=0.91 in VSD ; Y=0.86X+0.15, r=0.78 in ASD and Y=0.72X+0.24, r=0.80 in PDA). Thus 201-TlCl myocardial imaging was useful method to evaluate right ventricular pressure noninvasively in congenital cardiac disease. (author)

  3. Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography

    DEFF Research Database (Denmark)

    Rochitte, Carlos E; George, Richard T; Chen, Marcus Y; Arbab-Zadeh, Armin; Dewey, Marc; Miller, Julie M; Niinuma, Hiroyuki; Yoshioka, Kunihiro; Kitagawa, Kakuya; Nakamori, Shiro; Laham, Roger; Vavere, Andrea L; Cerci, Rodrigo J; Mehra, Vishal C; Nomura, Cesar; Kofoed, Klaus F; Jinzaki, Masahiro; Kuribayashi, Sachio; de Roos, Albert; Laule, Michael; Tan, Swee Yaw; Hoe, John; Paul, Narinder; Rybicki, Frank J; Brinker, Jeffery A; Arai, Andrew E; Cox, Christopher; Clouse, Melvin E; Di Carli, Marcelo F; Lima, Joao A C

    2014-01-01

    AIMS: To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed tomography (SPECT). METHODS AND RESULTS: We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ?50% stenosis...

  4. Investigation of optimal acquisition time of myocardial perfusion scintigraphy using cardiac focusing-collimator

    Science.gov (United States)

    Niwa, Arisa; Abe, Shinji; Fujita, Naotoshi; Kono, Hidetaka; Odagawa, Tetsuro; Fujita, Yusuke; Tsuchiya, Saki; Kato, Katsuhiko

    2015-03-01

    Recently myocardial perfusion SPECT imaging acquired using the cardiac focusing-collimator (CF) has been developed in the field of nuclear cardiology. Previously we have investigated the basic characteristics of CF using physical phantoms. This study was aimed at determining the acquisition time for CF that enables to acquire the SPECT images equivalent to those acquired by the conventional method in 201TlCl myocardial perfusion SPECT. In this study, Siemens Symbia T6 was used by setting the torso phantom equipped with the cardiac, pulmonary, and hepatic components. 201TlCl solution were filled in the left ventricular (LV) myocardium and liver. Each of CF, the low energy high resolution collimator (LEHR), and the low medium energy general purpose collimator (LMEGP) was set on the SPECT equipment. Data acquisitions were made by regarding the center of the phantom as the center of the heart in CF at various acquisition times. Acquired data were reconstructed, and the polar maps were created from the reconstructed images. Coefficient of variation (CV) was calculated as the mean counts determined on the polar maps with their standard deviations. When CF was used, CV was lower at longer acquisition times. CV calculated from the polar maps acquired using CF at 2.83 min of acquisition time was equivalent to CV calculated from those acquired using LEHR in a 180°acquisition range at 20 min of acquisition time.

  5. Optimized Butterworth filters for 99mTc myocardial perfusion SPECT images. An evaluation

    International Nuclear Information System (INIS)

    We assessed the cut-off frequency (Fc) of the Butterworth filter in myocardial nuclear imaging. The RH-2 was used as a myocardial phantom. The parameters are nuclides (201Tl and 99mTc) and the collimators (LEGP and LEHR). Radius direction distribution function Pr(n) was applied to SPECT images for frequency space analysis, and NMSE (Normalized Mean Squared Error) method was used for assessment in real space. In both of these method of analysis, the optimal cut-off frequency varies depending on the nuclide and collimator: Fc in use of 201Tl are 0.245 (cycles/pixel) with LEGP, and 0.250 with LEHR. However, those in use of 99mTc are 0.25 with LEGP, and 0.27 with LEHR, respectively. The image spectrum varies depending also on the injected dose in 99mTc. With 185 MBq, the optimal cut-off frequency was less than that with 740 MBq. We concluded that the cut-off frequency of the Butterworth filter should be changed in reconstructing images according to the collimator, nuclide, and injected dose. (author)

  6. Value of 201-thallium serial myocardial imaging in coronary heart disease

    International Nuclear Information System (INIS)

    There has been clinical evidence that a perfusion defect on a stress image fills overtime. The diagnostic value of initial and 120 min post exercise redistribution thallium-201 myocardial images (RMI) was determined in 120 pts, with suspected coronary heart disease (CAD), all of whom had coronary arteriography. Significant (>= 75%) lesions were present in 88 pts. 30 pts. without CAD showed a normal tracer uptake immediately after exercise. Scintigrams taken 120 min after exercise revealed a decrease of 201-Tl concentration in every area of the myocardium. 80 pts. with CAD showed an area of decreased tracer uptake in the inital scans. 120 min RMI in 51 pts. revealed a significant increase (p > 0.01) of countrate time ratio in previous underperfused areas. In 37 pts. persistent defects were present, in every case the defect correlated with the site of a myocardial infarction as determined by the finding of an akinetic area in the left ventricular angiogram. Thus RMI following a single dose of 201 Tl can differentiate between scar- and exercise-induced transient ischemia. (orig.) 891 AJ/orig. 892 MB

  7. Evaluation of left ventricular hypertrophy using thallium-201 myocardial scintigraphy, echocardiography and vectorcardiography

    International Nuclear Information System (INIS)

    Thallium-201 (201Tl) myocardial scintigraphy was performed in 40 patients with left ventricular hypertrophy(LVH). Twelve out of 40 patients had pressure overloading (Aortic stenosis: 5, Hypertension: 7), 14 patients had volume overloading (Aortic regurgitation: 9, Mitral regurgitation: 5) and 14 had idiopathic cardiomyopathy (Hypertrophic type (HCM): 8, Congestive type (CCM): 6), respectively. LV area, LV uptake index and Wall uptake ratio were calculated from left anterior oblique view of 201Tl myocardial images. These three indices of both pressure overloading and volume overloading were significantly higher than those of controls. The degree of LVH was indicated by both LV area and LV uptake index. LV area was significantly larger in volume overloading than in pressure overloading. In idiopathic cardiomyopathy, these three indices of HCM and LV area and LV uptake index of CCM were significantly increased compared with those of controls. LV area of CCM was significantly larger than that of HCM, while Wall uptake ratio of HCM was significantly higher than that of CCM. LV uptake index and Wall uptake ratio of HCM became higher according as left ventricular cavity became smaller. LV area of CCM became larger in proportion as left ventricular cavity became larger and as left ventricular wall thickness became thinner. (author)

  8. Optimal preprocessing Butterworth-Wiener filter for Tl-201 myocardial SPECT

    International Nuclear Information System (INIS)

    The optimal frequency characteristic of Butterworth-Wiener filters (BWF) for improving the image quality of 201Tl myocardial SPECT was determined by a phantom experiment. Thirty-two projection images of the phantom containing 11.1 MBq of 201Tl with 4 different cold lesions were collected during a 1800 arc of a gamma camera. A set of the projection images were processed with each of 27 different BWFs, and SPECT images were reconstructed by Shepp-Logan filtered backprojection. The SPECT images were evaluated for their diagnostic ability to visibly detect the cold lesions by four nuclear medicine physicians. The lesion contrasts were used as an adjunctive tool to determine the optimum filter. The optimal combination of the parameters determining BWF characteristics (for the data of about 100 count/pixel at the myocardium) is: 1) cutoff of 0.25/pixel, 2) FWHM of 3 pixels, 3) noise/signal ratio of 0.02. FWHM and noise/signal ratio affected lesion contrast much less than cutoff frequency. Clinical myocardial SPECT images processed with the optimal BWF showed less noise and sharper delineation of the myocardium. (orig.)

  9. The characteristics of myocardial fatty acid metabolism in patients with left ventricular hypertrophy

    International Nuclear Information System (INIS)

    We evaluated the characteristics of myocardial fatty acid metabolism in patients with left ventricular hypertrophy (LVH). Myocardial imaging with 123I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) was performed in 28 patients with hypertrophic cardiomyopathy (HCM), 15 patients with hypertensive heart disease (HHD), 13 patients with aortic stenosis (AS) and 8 normal controls (NC). The patients with HCM consisted of 13 patients of asymmetric septal hypertrophy (ASH), 7 patients of diffuse hypertrophy (Diffuse-HCM) and 8 patients of apical hypertrophy (APH). Planar and SPECT images of BMIPP were acquired 15 minutes and 4 hours after tracer injection. Resting 201Tl SPECT images and echocardiography were also performed on other days. We calculated heart/mediastinum count ratio and washout rate of BMIPP by using planar image. In patients with LVH, the incidence of reduced BMIPP uptake was more frequent than that of reduced 201Tl uptake. In delayed images, more than 60% of patients with LVH reduced BMIPP uptake, especially remarkable for patients with ASH and APH. The washout rate of all cardiac hypertrophic disorders was tended to be higher than that of normal subjects. Reduced BMIPP uptake was frequently found in septal portion of anterior and inferior wall in patients with ASH, in inferior wall in patients with Diffuse-HCM and HHD, in apex in patients with APH and AS. These results suggest that BMIPP scintigraphy can differentiate three types of cardiac hypertrophy. (author)

  10. The diagnostic value for ischemic heart disease of thallium-201 myocardial scintigraphy by intravenous infusion of SUNY4001 (adenosine). The report of clinical trial at multi-center. Phase III

    International Nuclear Information System (INIS)

    With two hundreds and seven patients unable to exercise adequately, the diagnostic accuracy and adverse reaction of 201Tl myocardial scintigraphy with the pharmacologic stress by SUNY4001 (adenosine) infusion were studied. Adenosine was infused for six minutes at the rate of 120 ?g/kg/min, and then 201Tl was injected after three minutes from the start of infusion. The early and delayed images were obtained by SPECT imaging. According to angiography, ?American Heart Association (AHA) 90% stenosis was defined as significant. The sensitivity of detecting coronary artery disease was 87.1% and the specificity was 46.0%. Adverse reactions occurred in 66.7% of the patients, most of which disappeared shortly with no need for treatment. Major adverse reactions were chest pain/discomfort (30.4%), flushing/feeling of warmth (22.4%) and blood pressure decrease (17.4%). Adenosine infusion caused slight decrease in blood pressure and increase in heart rate. These hemodynamic changes were resolved within several minutes from the termination of adenosine infusion. We concluded that adenosine-201Tl imaging is safe and useful to detect coronary artery disease in patients unable to exercise adequately. (author)

  11. Single-photon emitting diode in silicon carbide

    Science.gov (United States)

    Lohrmann, A.; Iwamoto, N.; Bodrog, Z.; Castelletto, S.; Ohshima, T.; Karle, T. J.; Gali, A.; Prawer, S.; McCallum, J. C.; Johnson, B. C.

    2015-07-01

    Electrically driven single-photon emitting devices have immediate applications in quantum cryptography, quantum computation and single-photon metrology. Mature device fabrication protocols and the recent observations of single defect systems with quantum functionalities make silicon carbide an ideal material to build such devices. Here, we demonstrate the fabrication of bright single-photon emitting diodes. The electrically driven emitters display fully polarized output, superior photon statistics (with a count rate of >300 kHz) and stability in both continuous and pulsed modes, all at room temperature. The atomic origin of the single-photon source is proposed. These results provide a foundation for the large scale integration of single-photon sources into a broad range of applications, such as quantum cryptography or linear optics quantum computing.

  12. Single-photon emitting diode in silicon carbide.

    Science.gov (United States)

    Lohrmann, A; Iwamoto, N; Bodrog, Z; Castelletto, S; Ohshima, T; Karle, T J; Gali, A; Prawer, S; McCallum, J C; Johnson, B C

    2015-01-01

    Electrically driven single-photon emitting devices have immediate applications in quantum cryptography, quantum computation and single-photon metrology. Mature device fabrication protocols and the recent observations of single defect systems with quantum functionalities make silicon carbide an ideal material to build such devices. Here, we demonstrate the fabrication of bright single-photon emitting diodes. The electrically driven emitters display fully polarized output, superior photon statistics (with a count rate of >300?kHz) and stability in both continuous and pulsed modes, all at room temperature. The atomic origin of the single-photon source is proposed. These results provide a foundation for the large scale integration of single-photon sources into a broad range of applications, such as quantum cryptography or linear optics quantum computing. PMID:26205309

  13. Generation of Fourier-transform-limited heralded single photons

    International Nuclear Information System (INIS)

    In this paper we study the spectral (temporal) properties of heralded single photon wave packets, triggered by the detection of an idler photon in the process of parametric down conversion. The generated single photons are studied within the framework of the chronocyclic Wigner function, from which the single photon spectral width and temporal duration can be computed. We derive specific conditions on the two-photon joint spectral amplitude which result in both pure and Fourier-transform-limited heralded single photons. Likewise, we present specific source geometries which lead to the fulfillment of these conditions and show that one of these geometries leads, for a given pump bandwidth, to the temporally shortest possible heralded single photon wave packets

  14. Indistinguishable single photons with real-time-programmable electronic triggering

    CERN Document Server

    Dada, Adetunmise C; Malein, Ralph N E; Koutroumanis, Antonios; Ma, Yong; Zajac, Joanna M; Lim, Ju Y; Song, Jin D; Gerardot, Brian D

    2016-01-01

    A key ingredient for quantum photonic technologies is an on-demand source of indistinguishable single photons. State-of-the-art indistinguishable-single-photon sources typically employ resonant excitation pulses with fixed repetition rates, creating a string of single photons with predetermined arrival times. However, in future applications, an independent electronic signal from a larger quantum circuit or network will trigger the generation of an indistinguishable photon. Further, operating the photon source up to the limit imposed by its lifetime is desirable. Here we report on the application of a true on-demand approach in which we can electronically trigger the precise arrival time of a single photon as well as control the excitation pulse duration. We investigate in detail the effect of finite duration of an excitation $\\pi$ pulse on the degree of photon antibunching. Finally, we demonstrate that highly indistinguishable single photons can be generated using this on-demand approach, enabling maximum fle...

  15. Excitation functions and yields of proton induced reactions at intermediate energies leading to important diagnostics radioisotopes of 52Fe, 77Br, 82Rb, 97Ru, 111In, 123I, 127Xe, 128Cs, 178Ta and 201Tl

    International Nuclear Information System (INIS)

    This report describes investigations of the excitation functions of the proton induced reactions on 14 targets (Mn, Co, Br, Rb, 99Tc, 113Cd, 114Cd, Cd, I, Cs, Ta, 206,207,208Pb) leading directly or indirectly to the formation of radionuclides 52Fe, 77Br, 82Rb, 97Ru, 111In, 123I, 127Xe, 128Cs, 178Ta and 201Tl frequently used in diagnostic procedures of nuclear medicine. The measurements of the excitation functions were made over a wide proton energy range from the reaction threshold up to 100 MeV using the stacked foil (or pellet) technique. Small energy steps were used to allow for accurate determination of the structure of excitation functions. For 97Ru, 111In and 127Xe formation with protons, new reaction channels and targets were used and data concerning this method are published for the first time. The data for 52Fe, 77Br, 82Rb, 123I, 128Cs and 201Tl obtained in the present work for the Ep=70-100 MeV region are also published for the first time. The measured excitation functions for the formation of desired (and undesired) radionuclides (altogether 28 excitation functions) are compared with the theoretical ones calculated on the basis of a hybrid model of nuclear reactions in the form of the Overlaid Alice computer code. In order to determine the contribution of the competitive reaction channels to the purity of the produced, desired radionuclide, the excitation functions of the accompanying reactions were also calculated. The 122 calculated excitation functions for the possible contaminant are given in the present work. The comparison of experimental excitation functions with the results of model calculations showed satisfactory agreement, especially if one considers, that no parameter adjustment for individual reaction products was undertaken. From the measured excitation functions the production yields for 28 radionuclides mentioned above have been determined (author). 262 refs, 65 figs, 34 tabs

  16. Evaluation of branched chain fatty acid, BMIPP (. beta. -methyl-. omega. -(p-iodophenyl)-pentadecanoic acid) for the myocardial imaging. Basic experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Yasuaki; Morishita, Takeshi; Yamazaki, Junichi and others

    1988-11-01

    Iodine-123 labeled branched chain fatty acid BMIPP (/sup ..beta../-methyl-..omega..-(p-iodophenyl)-pentadecanoic acid) was evaluated for the myocardial imaging experimentally. /sup 123/I-BMIPP was accumulated in the heart at 2 - 4 minutes after injection and retention in the heart was remarkable at 30 minutes. In the acute canine infarction model, infarcted area was recognized as a defect. Furthermore, in comparison between /sup 123/I-BMIPP and /sup 201/Tl-Cl, discrepancy between these images was recognized in the ischemic and infarcted area. BMIPP is of use in not only cardiomyopathy and hypertension, but ischemic heart desease.

  17. Heart rate induced changes of the 201Tl accumulation in the myocardium and pharmacological intervention with Saralasin at patients with VVI pacemakers

    International Nuclear Information System (INIS)

    The purpose of this study was to examine whether an increased heart rate and the resultant enhanced myocardial oxygen consumption in patients with VVI pacemakers are reflected in changes of myocardial Tl-201 uptake. In addition, we wanted to examine the direct action of the angiotensin II receptor blocker Saralasin on the myocardial Tl-201 distribution at increased pacing rates. We examined 13 unselected patients with transvenous VVI pacemakers. Fifteen minutes after increasing the pacing rate from 60/min. to 140/min (HR stress) we injected Tl-201, 2 mCi. After another 3 minutes camera images were obtained in the 300 LAO, 450 LAO, AP and LL views. In 6 patients (group I) Saralasin, 1g/kg/min. was injected at high pacing rates and additional myocardial images were recorded. Three hours after reducing the pacing rate to baseline resting scans were made. Of the 7 patients without Saralasin (group II), 4 showed areas of reduced uptake during the HR stress period, which were no longer demonstrable on the resting image. In 3 patients both the stress and the resting images were normal. In 5 patients of group I the rate-related areas of reduced uptake disappeared on Saralasin infusion inspite of the sustained HR stress. The scans were largely identical with the resting image. Three patients showed unchanged segmental defects throughout. At increased pacing rates and elevated myocardial oxygen consumption reversible uptake deficits were demonstrated. In these tachycardiainduced lesions, Saralasin was found to enhance the Thallium uptake. (Author)

  18. Plasmon enhanced single-photon detection

    Science.gov (United States)

    Szekeres, Gábor; Szenes, András.; Csete, Mária

    2013-09-01

    Novel infrared superconducting nanowire single-photon detectors (SNSPD) were designed, which comprise a meandered pattern of niobium-nitride (NbN) stripes and different integrated plasmonic structures on silica substrate. To enhance absorptance of 1550 nm wavelength p-polarized light, patterns with p=264 nm periodicity were investigated, while to enhance detection efficiency, patterns with P=792.5 nm periodicity commensurate with the wavelength of surface plasmon polaritons at silica-gold interface were also designed. In OC-SNSPDs integrated with ~quarter-photonicwavelength nano-optical cavity closed by a gold reflector, the highest 63/27 % absorptance was attained in p/P-pitch design at perpendicular incidence onto NbN patterns in P-orientation corresponding to incidence plane parallel to the stripes, due to the E-field antinode at the NbN-silica interface. In NCAI-SNSPDs, where each NbN stripe is located at the entrance of a quarter-plasmon-wavelength MIM nano-cavity, enhanced 85.1/34 % absorptance is attainable in p/Ppitch design at perpendicular incidence in S-orientation, when the incidence plane is perpendicular to the integrated pattern, due to collective resonances. The maximal 95.3/70.3 % absorptances are attained at large tilting corresponding to plasmonic Brewster angles via ultra-broadband tunneling. In NCDAI-SNSPDs the longer vertical gold segments with P-pitch, which can be embedded into the silica substrate via two-step lithography, enable to attain large absorptance at small polar angles in S-orientation, due to efficient grating-coupling phenomenon. The highest 92.7/75 % absorptances are attained at 19.85°/19.35° polar angles in p/P-pitch design. P-pitch NCDAI-SNSPD supporting coupled surface waves capable of ensuring synchronous E-field enhancement below the NbN stripes is proposed for detection efficiency maximization in specific spectral-bands.

  19. Radiation burst from a single ?-photon field

    International Nuclear Information System (INIS)

    The radiation burst from a single ?-photon field interacting with a dense resonant absorber is studied theoretically and experimentally. This effect was discovered for the fist time by P. Helisto et al.[Phys. Rev. Lett. 66, 2037 (1991)] and it was named the ''gamma echo''. The echo is generated by a 180° phase shift of the incident radiation field, attained by an abrupt change of the position of the absorber with respect to the radiation source during the coherence time of the photon wave packet. Three distinguishing cases of the gamma echo are considered; i.e., the photon is in exact resonance with the absorber, close to resonance (on the slope of the absorption line), and far from resonance (on the far wings of the resonance line). In resonance the amplitude of the radiation burst is two times larger than the amplitude of the input radiation field just before its phase shift. This burst was explained by Helisto et al. as a result of constructive interference of the coherently scattered field with the phase-shifted input field, both having almost the same amplitude. We found that out of resonance the scattered radiation field acquires an additional component with almost the same amplitude as the amplitude of the incident radiation field. The phase of the additional field depends on the optical thickness of the absorber and resonant detuning. Far from resonance this field interferes destructively with the phase-shifted incident radiation field and radiation quenching is observed. Close to resonance the three fields interfere constructively and the amplitude of the radiation burst is three times larger than the amplitude of the input radiation field.

  20. Imaging of brain tumors in AIDS patients by means of dual-isotope thallium-201 and technetium-99m sestamibi single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    De La Pena, R.C.; Ketonen, L.; Villanueva-Meyer, J. [Dept. of Radiology, Univ. of Texas, Galveston (United States)

    1998-10-01

    Our aim was to evaluate the use of dual-isotope thallium-201 (Tl) and technetium-99m sestamibi (sestamibi) simultaneous acquisition in brain single-photon emission tomography (SPET) for the differentiation between brain lymphoma and benign central nervous system (CNS) lesions in AIDS patients. Thirty-six consecutive patients with enhancing mass lesions on magnetic resonance (MR) imaging were included in the study. SPET of the brain was performed to obtain simultaneous Tl and sestamibi images. Regions-of-interest were drawn around the lesion and on the contralateral side to calculate uptake ratios. The final diagnosis was reached by pathologic findings in 17 patients and clinical and/or MR follow-up in 19 patients. Of the 36 patients, 11 had brain lymphoma, 1 glioblastoma multiforme, 15 toxoplasmosis and 9 other benign CNS lesions. Correlation between SPET and the final diagnosis revealed in 10 true-positive, 23 true-negative, 1 false-positive and 2 false-negative studies. All patients with toxoplasmosis had negative scans. A patient with a purulent infection had positive scans. Tl and sestamibi scans were concordant in every lesion. The same lesions that took up Tl were also visualized with sestamibi. However, sestamibi scans showed higher lesion-to-normal tissue uptake ratios (3.7{+-}1.8) compared with those of Tl (2.3{+-}0.8, P<0.002). Simultaneous acquisition of Tl and sestamibi can help differentiate CNS lymphoma from benign brain lesions in AIDS patients. (orig.) With 2 figs., 2 tabs., 34 refs.

  1. Single photon emission from ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sumin; Ton-That, Cuong; Phillips, Matthew R.; Aharonovich, Igor, E-mail: igor.aharonovich@uts.edu.au [School of Physics and Advanced Materials, University of Technology Sydney, Ultimo, New South Wales 2007 (Australia); Johnson, Brett C. [Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Castelletto, Stefania [School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria 3000 (Australia)

    2014-06-30

    Room temperature single photon emitters are very important resources for photonics and emerging quantum technologies. In this work, we study single photon emission from defect centers in 20?nm zinc oxide (ZnO) nanoparticles. The emitters exhibit bright broadband fluorescence in the red spectral range centered at 640?nm with polarized excitation and emission. The studied emitters showed continuous blinking; however, bleaching can be suppressed using a polymethyl methacrylate coating. Furthermore, hydrogen termination increased the density of single photon emitters. Our results will contribute to the identification of quantum systems in ZnO.

  2. Single photon emission from ZnO nanoparticles

    CERN Document Server

    Choi, Sumin; Castelletto, Stefania; Ton-That, Cuong; Phillips, Matthew R; Aharonovich, Igor

    2014-01-01

    Room temperature single photon emitters are very important resources for photonics and emerging quantum technologies. In this work we study single photon emission from defect centers in 20 nm zinc oxide (ZnO) nanoparticles. The emitters exhibit bright broadband fluorescence in the red spectral range centered at 640 nm with polarized excitation and emission. The studied emitters showed continuous blinking, however, bleaching can be suppressed using a polymethyl methacrylate (PMMA) coating. Furthermore, hydrogen termination increased the density of single photon emitters. Our results will contribute to the identification of quantum systems in ZnO.

  3. Single photon emission from ZnO nanoparticles

    International Nuclear Information System (INIS)

    Room temperature single photon emitters are very important resources for photonics and emerging quantum technologies. In this work, we study single photon emission from defect centers in 20?nm zinc oxide (ZnO) nanoparticles. The emitters exhibit bright broadband fluorescence in the red spectral range centered at 640?nm with polarized excitation and emission. The studied emitters showed continuous blinking; however, bleaching can be suppressed using a polymethyl methacrylate coating. Furthermore, hydrogen termination increased the density of single photon emitters. Our results will contribute to the identification of quantum systems in ZnO.

  4. Detection of myocardial lesions by dipyridamole thallium-201 scintigraphy in patients with rheumatoid arthritis

    International Nuclear Information System (INIS)

    Dipyridamole thallium-201 (Tl) scintigraphic studies to evaluate microcirculation of the heart were performed in 54 patients with rheumatoid arthritis (RA) who had neither cardiac complaints nor myocardial damages on ECG. Twenty seven of 54 RA patients showed some perfusion defects in this study. The values of ESR, CRP and rheumatoid factors of IgM and IgG classes were significantly higher in these patients with perfusion defect compared with those in the rest of RA patients with normal perfusion. The scintigraphic perfusion defects improved relating with the reduction of inflammatory activities of RA. The histological specimens of heart in 12 RA autopsy cases were reviewed to study the etiology of these perfusion defects. In 7 of 12 cases, microvasculitis and microthrombosis were observed without any macroscopic findings compatible with myocardial infarction. Our results suggest that RA patients have frequently microcirculatory disturbances in the heart due to microvasculitis without any clinical symptoms of ECG changes. (author)

  5. Thallium-201 myocardial imaging as a selection method for the coronary care unit

    International Nuclear Information System (INIS)

    In many patients admitted to the coronary care unit, the diagnosis of acute myocardial infarction is evident at the time of arrival at the hospital. Nevertheless, a substantial group of patients still remains in whom initial evaluation provides a questionable history and a nondiagnostic electrocardiogram. Results suggested that 201Tl scintigraphy may have potential value to serve as an appropriate means of selecting patients for admission to the coronary care unit. In order to evaluate this possibility, the authors performed a prospective study from September 1975 to September 1976. During this period 1861 patients were refered to the coronary care unit because of presumed acute myocardial infarction. The study concludes that for patients in whom the history and the electrocardiogram are of little help in decision making, thallium-201 scintigraphy can be viewed as an additional and important diagnostic method, which improves efficient management of patients with potential coronary artery disease syndrome. (Auth.)

  6. Preparation and evaluation of technetium-99m labeled cardiac glycoside derivatives as potential myocardial imaging agent

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Mridula; Sarkar, H.S.; Chatterjee, Mita; Banerjee, Somenath

    1988-01-01

    Three cardiac glycosides, two natural, cymarin and convallotoxin and one synthetic, strophanthidin-..beta..-D-glucoside were converted to their thiosemicarbazone and subsequently radiolabeled with sup(99m)Tc by chelation. The resulting radioactive chelate complexes were evaluated in animals to determine the suitability of this class of compounds for myocardial imaging. It was observed from the animal biodistribution data of the three radioactive compounds that there was a considerable variation in the heart to non-target organ uptake ratio. A possible explanation of this variation was offered in the light of their lipophilic character, protein binding ability and affinity towards non-target receptors. It is anticipated that this study may help to develop a sup(99m)Tc-cardiac glycoside complex with better distribution characteristics, and such a compound may offer a suitable alternative to /sup 201/Tl, which is at present used for myocardial imaging.

  7. Preparation and evaluation of technetium-99m labeled cardiac glycoside derivatives as potential myocardial imaging agent

    International Nuclear Information System (INIS)

    Three cardiac glycosides, two natural, cymarin and convallotoxin and one synthetic, strophanthidin-?-D-glucoside were converted to their thiosemicarbazone and subsequently radiolabeled with sup(99m)Tc by chelation. The resulting radioactive chelate complexes were evaluated in animals to determine the suitability of this class of compounds for myocardial imaging. It was observed from the animal biodistribution data of the three radioactive compounds that there was a considerable variation in the heart to non-target organ uptake ratio. A possible explanation of this variation was offered in the light of their lipophilic character, protein binding ability and affinity towards non-target receptors. It is anticipated that this study may help to develop a sup(99m)Tc-cardiac glycoside complex with better distribution characteristics, and such a compound may offer a suitable alternative to 201Tl, which is at present used for myocardial imaging. (author)

  8. Single-photon spectroscopy of a single molecule

    CERN Document Server

    Rezus, Y L A; Lettow, R; Renn, A; Zumofen, G; Goetzinger, S; Sandoghdar, V

    2011-01-01

    Exploring the interaction of light and matter at the ultimate limit of single photons and single emitters is of great interest both from a fundamental point of view and for emerging applications in quantum engineering. However, the difficulty of generating single photons with specific wavelengths, bandwidths and brightness as well as the weak interaction probability of a single photon with an optical emitter pose a formidable challenge toward this goal. Here, we demonstrate a general approach based on the creation of single photons from a single emitter and their use for performing spectroscopy on a second emitter situated at a distance. Although we used organic molecules as emitters, our strategy is readily extendable to other material systems such as quantum dots and color centers. Our work ushers in a new line of experiments that provide access to the coherent and nonlinear couplings of few emitters and few propagating photons.

  9. Performance of single-photon-counting PILATUS detector modules

    OpenAIRE

    P. Kraft; Bergamaschi, A.; Broennimann, Ch.; R. Dinapoli; Eikenberry, E F; Henrich, B.; JOHNSON, I; A. Mozzanica; Schlepütz, C M; Willmott, P. R.; Schmitt, B

    2009-01-01

    Characterization of PILATUS single-photon-counting X-ray detector modules regarding charge sharing, energy resolution and rate capability is presented. The performance of the detector was tested with surface diffraction experiments at the synchrotron.

  10. ASP: a search for single photon events at PEP

    International Nuclear Information System (INIS)

    The ASP search for events with a single photon and no other observed particles is reviewed. New results on the number of neutrino generations and limits on selectron, photino, squark and gluino masses are presented

  11. A plasmonic nanoantenna based triggered single photon source

    CERN Document Server

    Straubel, Jako; Rockstuhl, Carsten; S?owik, Karolina

    2015-01-01

    Highly integrated single photon sources are key components in future quantum-optical circuits. Whereas the probabilistic generation of single photons can routinely be done by now, their triggered generation is a much greater challenge. Here, we describe the triggered generation of single photons in a hybrid plasmonic device. It consists of a lambda-type quantum emitter coupled to a multimode optical nanoantenna. For moderate interaction strengths between the subsystems, the description of the quantum optical evolution can be simplified by an adiabatic elimination of the electromagnetic fields of the nanoantenna modes. This leads to an insightful analysis of the emitter's dynamics, entails the opportunity to understand the physics of the device, and to identify parameter regimes for a desired operation. Even though the approach presented in this work is general, we consider a simple exemplary design of a plasmonic nanoantenna, made of two silver nanorods, suitable for triggered generation of single photons.

  12. Secure communication with a heralded single-photon source

    International Nuclear Information System (INIS)

    Secure long distance communication over optical fibres requires robust data encryption. While the encryption itself can be conducted using classical algorithms, there is no unconditionally secure method of classical key distribution. Quantum key distribution (QKD), on the other hand, can provide users of the optical networks with unconditionally secure keys. Since QKD is based on single-photon transmission, one of the challenging tasks is to overcome the distance limitation imposed by the losses in optical fibres. In this work we show that single-photon based QKD outperforms the industry-standard weak coherent pulse approach. We also present our recent experimental results on building a heralded single-photon source based on spontaneous parametric down-conversion of CW light and discuss problems and challenges of heralded single-photon generation in the CW regime

  13. Controllable single photon stimulation of retinal rod cells

    CERN Document Server

    Phan, Nam Mai; Bessarab, Dmitri A; Krivitsky, Leonid A

    2013-01-01

    Retinal rod cells are commonly assumed to be sensitive to single photons [1, 2, 3]. Light sources used in prior experiments exhibit unavoidable fluctuations in the number of emitted photons [4]. This leaves doubt about the exact number of photons used to stimulate the rod cell. In this letter, we interface rod cells of Xenopus laevis with a light source based on Spontaneous Parametric Down Conversion (SPDC) [5], which provides one photon at a time. Precise control of generation of single photons and directional delivery enables us to provide unambiguous proof of single photon sensitivity of rod cells without relying on the statistical assumptions. Quantum correlations between single photons in the SPDC enable us to determine quantum efficiency of the rod cell without pre-calibrated reference detectors [6, 7, 8]. These results provide the path for exploiting resources offered by quantum optics in generation and manipulation of light in visual studies. From a more general perspective, this method offers the ult...

  14. Continuous variable teleportation of single photon states (Proceedings version)

    OpenAIRE

    Ide, Toshiki; Hofmann, Holger F; Kobayashi, Takayoshi; Furusawa, Akira

    2001-01-01

    We investigate the changes to a single photon state caused by the non-maximal entanglement in continuous variable quantum teleportation. It is shown that the teleportation measurement introduces field coherence in the output.

  15. Quantum teleportation of a single-photon wave packet

    OpenAIRE

    Molotkov, S. N.

    1998-01-01

    A quantum teleportation scheme based on the EPR-pair entangled with respect to the ``energy+time'' variables is proposed. Teleportation of the multimode state of a single-photon wave packet is considered.

  16. Single-photon indistinguishability: influence of phonons

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Lodahl, Peter

    2012-01-01

    Recent years have demonstrated that the interaction with phonons plays an important role in semiconductor based cavity QED systems [2], consisting of a quantum dot (QD) coupled to a single cavity mode [Fig. 1(a)], where the phonon interaction is the main decoherence mechanism. Avoiding decoherence effects is important in linear optical quantum computing [1], where a device emitting fully coherent indistinguishable single photons on demand, is the essential ingredient. In this contribution we present a numerically exact simulation of the effect of phonons on the degree of indistinguishability of photons emitted from a solid-state cavity QED system. Our model rigorously describes non-Markovian effects to all orders in the phonon coupling constant, being based on an exact diagonalization procedure accounting for the time evoluiton of one-time and two-time photon correlation funcitons. We compare to standard approaches for treating the phonon interaction, namely the Markovian Lindblad formalism and the long-time limit of the non-Markovian timeconvolution-less (TCL) approach, and find large quantitative and qualitative differences [3]. Figures 1(b) and (c) show the calculated indistingusihability as a function of the QD-cavity coupling strength for light emitted from the QD and the cavity, respectively, for all the employed methods. Both the Lindblad and TCL theories deviate significantly from our exact results, where, importantly, the exact results predict a pronounced maximum in the degree of indistinguishability, absent in the approximate theories. The maximum arises due to virtual processes in the highly non-Markovian short-time regime, which dominate the decoherence for small QD-cavity coupling, and phonon-mediated real transitions between the upper and lower polariton branches in the long-time regime, dominating the decoherence for large QD-cavity coupling. Our method captures the physics of the regime of small and as well as large QD-cavity coupling, both corresponding to experimentally relevant situations. Importantly, the commonly used Lindblad formalism fails completely in describing the variations of the indistinguishability predicted by the two other models.

  17. Ultrafast electrical control of a resonantly driven single photon source

    CERN Document Server

    Cao, Y; Ellis, D J P; Farrer, I; Ritchie, D A; Shields, A J

    2015-01-01

    We demonstrate generation of a pulsed stream of electrically triggered single photons in resonance fluorescence, by applying high frequency electrical pulses to a single quantum dot in a p-i-n diode under resonant laser excitation. Single photon emission was verifed, with the probability of multiple photon emission reduced to 2.8%. We show that despite the presence of charge noise in the emission spectrum of the dot, resonant excitation acts as a filter to generate narrow bandwidth photons.

  18. Single-Photon Techniques for Standard CMOS Digital ICs

    OpenAIRE

    Favi, Claudio

    2011-01-01

    The advent of single-photon detectors known as Single-Photon Avalanche Diodes in standard CMOS technology opened the way to new perspectives in integrating these ultra sensitive light sensors with digital logic. Light has some interesting properties that attracted researchers in computer and electronics for a long time. Its weightlessness nature makes it a candidate to replace electrons when it didn't already do so. This is particularly true for long ...

  19. Single photon counting imaging system via compressive sensing

    OpenAIRE

    Yu, Wen-Kai; Liu, Xue-feng; Yao, Xu-Ri; WANG, CHAO; Gao, Shang-Qi; Zhai, Guang-Jie; Zhao, Qing; Ge, Mo-lin

    2012-01-01

    An imaging system based on single photon counting and compressive sensing (ISSPCCS) is developed to reconstruct a sparse image in absolute darkness. The single photon avalanche detector and spatial light modulator (SLM) of aluminum micro-mirrors are employed in the imaging system while the convex optimization is used in the reconstruction algorithm. The image of an object in the very dark light can be reconstructed from an under-sampling data set, but with very high SNR and ...

  20. Fast quantum dot single photon source triggered at telecommunications wavelength

    OpenAIRE

    Rivoire, Kelley; Buckley, Sonia; Majumdar, Arka; Kim, Hyochul; Petroff, Pierre; Vuckovic, Jelena

    2010-01-01

    We demonstrate a quantum dot single photon source at 900 nm triggered at 300 MHz by a continuous wave telecommunications wavelength laser followed by an electro-optic modulator. The quantum dot is excited by on-chip-generated second harmonic radiation, resonantly enhanced by a GaAs photonic crystal cavity surrounding the InAs quantum dot. Our result suggests a path toward the realization of telecommunications-wavelength-compatible quantum dot single photon sources with speed...

  1. Single photon laser altimeter data processing, analysis and experimental validation

    Science.gov (United States)

    Vacek, Michael; Peca, Marek; Michalek, Vojtech; Prochazka, Ivan

    2015-10-01

    Spaceborne laser altimeters are common instruments on-board the rendezvous spacecraft. This manuscript deals with the altimeters using a single photon approach, which belongs to the family of time-of-flight range measurements. Moreover, the single photon receiver part of the altimeter may be utilized as an Earth-to-spacecraft link enabling one-way ranging, time transfer and data transfer. The single photon altimeters evaluate actual altitude through the repetitive detections of single photons of the reflected laser pulses. We propose the single photon altimeter signal processing and data mining algorithm based on the Poisson statistic filter (histogram method) and the modified Kalman filter, providing all common altimetry products (altitude, slope, background photon flux and albedo). The Kalman filter is extended for the background noise filtering, the varying slope adaptation and the non-causal extension for an abrupt slope change. Moreover, the algorithm partially removes the major drawback of a single photon altitude reading, namely that the photon detection measurement statistics must be gathered. The developed algorithm deduces the actual altitude on the basis of a single photon detection; thus, being optimal in the sense that each detected signal photon carrying altitude information is tracked and no altitude information is lost. The algorithm was tested on the simulated datasets and partially cross-probed with the experimental data collected using the developed single photon altimeter breadboard based on the microchip laser with the pulse energy on the order of microjoule and the repetition rate of several kilohertz. We demonstrated that such an altimeter configuration may be utilized for landing or hovering a small body (asteroid, comet).

  2. Heralded generation of single photons in pure quantum states

    OpenAIRE

    L. Zhang; Soeller, C; Cohen, O; Smith, BJ; Walmsley, IA

    2012-01-01

    Sources of single photons in pure quantum states are essential to many quantum optics applications. We explore a technique, known as group-velocity matching, that enables the heralded generation of pure single photons through nonlinear optical processes. It reduces or eliminates the requirement of spectral filtering that conventional sources rely on to achieve high purity, therefore increasing both heralding efficiency and photon flux. Implementation in both spontaneous parametric downconvers...

  3. Advances in single-photon counting and fiber metrology

    OpenAIRE

    Eraerds, Patrick

    2010-01-01

    Single-photon detectors on the one hand and optical fibers for telecommunication on the other are technical fields of high importance in science and daily life. With the advent of fiber-based quantum communication and fiber metrology applying single-photon detectors, a direct link has been established. The work presented in this thesis is devoted to new techniques and developments in this environment.

  4. Single-photon imaging in complementary metal oxide semiconductor processes

    OpenAIRE

    Charbon, E.

    2014-01-01

    This paper describes the basics of single-photon counting in complementary metal oxide semiconductors, through single-photon avalanche diodes (SPADs), and the making of miniaturized pixels with photon-counting capability based on SPADs. Some applications, which may take advantage of SPAD image sensors, are outlined, such as fluorescence-based microscopy, three-dimensional time-of-flight imaging and biomedical imaging, to name just a few. The paper focuses on architectures that are best suited...

  5. A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism.

    Science.gov (United States)

    Ko, Toshiyuki; Utanohara, Yuko; Suzuki, Yasuhiro; Kurihara, Makiko; Iguchi, Nobuo; Umemura, Jun; Sumiyoshi, Tetsuya; Tomoike, Hitonobu

    2014-09-13

    Simultaneous dual-isotope SPECT imaging with 201Tl and (123)I-?-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion-metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, (99m)Tc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of (99m)Tc and (123)I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between (99m)Tc and (123)I. In the subsequent clinical study, (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by (99m)Tc-MIBI and (123)I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional (201)TlCl/(123)I-BMIPP dual-isotope imaging, the use of (99m)Tc-MIBI instead of (201)TlCl improves image quality as well as lowers radiation exposure. PMID:25217037

  6. Usefulness of myocardial imaging by 123I-MIBG in assessment of diabetic neuropathy

    International Nuclear Information System (INIS)

    In diabetic patients with autonomic neuropathy, it is suggested that there is a reduced uptake of 123I-metaiodobenzylguanidine (MIBG) in the heart. We compared the difference of myocardial 123I-MIBG accumulation between 4 diabetic patients with triopathy and 6 patients without it. In all 10 patients, coronary angiography and 201Tl imaging (rest and 4 hours later) were performed. 123I-MIBG (111 MBq) was administered intravenously and its imaging was recorded on 15 minutes and 4 hours after injection. In all 4 cases with triopathy, 123I-MIBG imaging showed defect in apical and inferior region. In 2 out of 6 cases without triopathy, rapid clearance was noticed in apical and inferior region. There was no significant stenosis in right coronary artery and no defect in initial and delayed 201Tl images in all cases. We concluded that diabetic autonomic neuropathy in the heart was prominent in apical and inferior region and 123I-MIBG imaging might be useful for the evaluation of degrees in diabetic neuropathy. (author)

  7. Scintigraphic evaluation of regional myocardial sympathetic activity in patients with hypertrophic cardiomyopathy. Comparison between asymmetrical hypertrophic cardiomyopathy and apical hypertrophy

    International Nuclear Information System (INIS)

    Using 123I-MIBG (metaiodobenzylguanidine) and 201Tl imagings, an examination concerning the relation between the hypertrophic region and its sympathetic nervous function was done. Subjects were 12 normal adults (4 males and 8 females, mean age 61.3 yr), 13 patients with asymmetrical hypertrophic cardiomyopathy (10 males and 3 females, 63.9 yr) and 13 patients with apical hypertrophy (9 males and 4 females, 67.2 yr). The SPECT apparatus was Toshiba two-gated gamma camera GCA 7200A. At 20 min and 3 hr after intravenous injection of 111 MBq of 123I-MIBG, myocardial SPECT and planar images were obtained with collimator LEHR under following conditions: photoelectric peak 159 KeV, window width 20%, matrix size 64 x 64 (256 x 256 for the planar image), step angle 6deg, 40 sec/step and 180deg for 1 camera. In another day, 201Tl SPECT and planar imagings were performed 10 min after intravenous injection of 111 MBq of 201Tl for the photoelectric peak 72 KeV under similar conditions to above. SPECT images were reconstructed using Butterworth filter and Shepp and Logan filter. Images were examined for the defect score, myocardium/mediastinum ratio, whole heart washout rate and regional washout rate. In the asymmetrical hypertrophic myopathy, abnormal sympathetic nerve function was recognized on the regions regardless of their disease severity while in the apical hypertrophy, abnormality was restricted on the apical region. Therefore, the two diseases were found different from each other from the aspect of sympathetic nerve functions. (K.H.)

  8. Clinical evaluation of myocardial scanning in 125 patients

    International Nuclear Information System (INIS)

    125 patients admitted to the coronary care unit with suspicion of acute myocardial infarction received sup(99m)Tc-pyrophosphate intraveniously, 12-120 hours after onset of symptoms. In five patients 201Tl was administered and in 12 patients 13NH+4 also was given. The patients were examined in the anterior posterior position, and in the left anterior oblique position 300 with a mobile gamma camera. Scintigrams were obtained initially at injection and then 60-90 min after radioisotope injection. The scintigrams were valuated with regard to presence, localization and intensity of radionuclide uptake in the myocardial area. From 89 patients with acute myocardial infarction, uptake was found in 82 (90%) with good correlation between ECG and scintigraphic localization. 9 out of 14 patients with unstable angina pectoris also showed an uptake. 9 patients with other cardiac diseases as well as 13 patients with non-cardiac diseases did not show any radionuclide uptake. When sup(99m)Tc-pyrophosphate scintigraphy was combined with regional myocardial perfusion scintigraphy with either 202Tl or 13NH+4 in 17 patients, 13 concordant cases were found, 4 pyrophosphate scintigraphy remained normal. By sup(99m)Tc-pyrophosphate scintigraphy a safe method in separating acute ischemic heart diseases from other diseases in patients with chest pain; dual isotope study increases its reliability

  9. Enhancement of Single-Photon Sources with Metamaterials

    Science.gov (United States)

    Shalaginov, M. Y.; Bogdanov, S.; Vorobyov, V. V.; Lagutchev, A. S.; Kildishev, A. V.; Akimov, A. V.; Boltasseva, A.; Shalaev, V. M.

    2015-06-01

    Scientists are looking for new, breakthrough solutions that can greatly advance computing and networking systems. These solutions will involve quantum properties of matter and light as promised by the ongoing experimental and theoretical work in the areas of quantum computation and communication. Quantum photonics is destined to play a central role in the development of such technologies due to the high transmission capacity and outstanding low-noise properties of photonic information channels. Among the vital problems to be solved in this direction, are efficient generation and collection of single photons. One approach to tackle these problems is based on engineering emission properties of available single-photon sources using metamaterials. Metamaterials are artificially engineered structures with sub-wavelength features whose optical properties go beyond the limitations of conventional materials. As promising single-photon sources, we have chosen nitrogen-vacancy (NV) color centers in diamond, which are capable to operate stably in a single-photon regime at room temperature in a solid state environment. In this chapter, we report both theoretical and experimental studies of the radiation from a nanodiamond single NV center placed near a hyperbolic metamaterial (HMM). In particular, we derive the reduction of excited-state lifetime and the enhancement of collected single-photon emission rate and compare them with the experimental observations. These results could be of great impact for future integrated quantum sources, especially owing to a CMOS-compatible approach to HMM synthesis.

  10. Peak systolic blood pressure in exercise testing is associated with scintigraphic severity of myocardial ischemia in patients with exercise-induced ST-segment depression

    International Nuclear Information System (INIS)

    Some electrocardiographic variables, including the degree of maximal ST-segment depression (STD), may not necessarily indicate the severity of exercise-induced myocardial ischemia. The present study examined whether maximal STD correlates with the severity and extent of exercise-induced myocardial ischemia, as assessed by thallium-201 (201Tl) imaging, and which parameter of exercise testing reflects scintigraphic severity and extent in 270 patients who had a 1 mm or greater horizontal or down-sloping STD on exercise 201Tl imaging. The scintigraphic severity and extent of exercise-induced ischemia was assessed and correlated with maximal STD, number of positive leads, workload, peak heart rate, peak systolic blood pressure (SBP), rate-pressure product, chest pain and the Duke treadmill score. Most of the scintigraphic markers of the severity and extent of ischemia had significant but weak correlation with all of those parameters. Multivariate analysis demonstrated that peak SBP and the Duke treadmill score (chest pain in only simple variables model) correlated independently with scintigraphic severity and extent of ischemia. Furthermore, most of the patients with a peak SBP of 200 mmHg or more had milder and less extensive ischemia. In patients with exercise-induced STD, the scintigraphic severity and extent of ischemia may be estimated by peak SBP and the Duke treadmill score. (author)

  11. Effects of propranolol and nifedipine on exercise-induced attack in patients variant angina: assessment by exercise thallium-201 myocardial scintigraphy with quantitative rotational tomography

    International Nuclear Information System (INIS)

    To examine the effects of propranolol and nifedipine on exercise-induced attack in patients with variant angina, exercise 201Tl myocardial scintigraphy with quantitative analysis by emission-computed tomography was performed in 20 patients with variant angina after oral propranolol (80 mg), nifedipine (20 mg), and placebo. Exercise-induced attack occurred in 11 patients on placebo, in 14 on propranolol, and in none on nifedipine. The exercise duration was significantly shorter in those on propranolol (p less than .05), but significantly longer in patients on nifedipine (p less than .05) than in those on placebo. The peak rate-pressure product was significantly lower in patients on propranolol (p less than .01), but did not change in those on nifedipine, as compared with that in patients on placebo. The size of the perfusion defect as measured by 201Tl tomography was significantly greater in patients on propranolol (p less than .05), but significantly less in those on nifedipine (p less than .01) than in those on placebo. In conclusion, propranolol does not suppress but rather may aggravate exercise-induced attack in patients with variant angina, while nifedipine suppresses it. This unfavorable effect of propranolol on exercise-induced attack in patients with variant angina is likely to be due to a reduction of regional myocardial blood flow

  12. Tailoring Single and Multiphoton Probabilities of a Single Photon On-Demand Source

    OpenAIRE

    Migdall, A. L.; Branning, D; Castelletto, S.; Ware, M.

    2002-01-01

    As typically implemented, single photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted independently, enabling a much better approximation of a source of single photons on d...

  13. Superconducting single photon detectors integrated with diamond nanophotonic circuits

    CERN Document Server

    Rath, Patrik; Ferrari, Simone; Sproll, Fabian; Lewes-Malandrakis, Georgia; Brink, Dietmar; Ilin, Konstantin; Siegel, Michael; Nebel, Christoph; Pernice, Wolfram

    2015-01-01

    Photonic quantum technologies promise to repeat the success of integrated nanophotonic circuits in non-classical applications. Using linear optical elements, quantum optical computations can be performed with integrated optical circuits and thus allow for overcoming existing limitations in terms of scalability. Besides passive optical devices for realizing photonic quantum gates, active elements such as single photon sources and single photon detectors are essential ingredients for future optical quantum circuits. Material systems which allow for the monolithic integration of all components are particularly attractive, including III-V semiconductors, silicon and also diamond. Here we demonstrate nanophotonic integrated circuits made from high quality polycrystalline diamond thin films in combination with on-chip single photon detectors. Using superconducting nanowires coupled evanescently to travelling waves we achieve high detection efficiencies up to 66 % combined with low dark count rates and timing resolu...

  14. Single-photon observables and preparation uncertainty relations

    Science.gov (United States)

    Guarnieri, G.; Motta, M.; Lanz, L.

    2015-07-01

    We propose a procedure to define all single-photon observables in a consistent and unified picture based on operational approach to quantum mechanics. We identify the suppression of zero-helicity states as a projection from an extended Hilbert space onto the physical single-photon Hilbert space. We show that all single-photon observables are in general described by positive-operator valued measures (POVMs), obtained by applying this projection to opportune projection-valued measures (PVMs) defined on the extended Hilbert space. The POVMs associated to momentum and helicity reduce to PVMs, unlike those associated to position and spin. This fact reflects the intrinsic unsharpness of these observables. We apply this formalism to study the preparation uncertainty relations for position and momentum and to compute the probability distribution of spin, for a broad class of Gaussian states. Results show quantitatively the enhancement of the statistical character of the theory.

  15. A Waveguide-Coupled On-Chip Single Photon Source

    CERN Document Server

    Laucht, A; Günthner, T; Hauke, N; Saive, R; Frédérick, S; Bichler, M; Amann, M -C; Holleitner, A W; Kaniber, M; Finley, J J

    2012-01-01

    We investigate single photon generation from individual self-assembled InGaAs quantum dots coupled to the guided optical mode of a GaAs photonic crystal waveguide. By performing confocal microscopy measurements on single dots positioned within the waveguide, we locate their positions with a precision better than 0.5 \\mu m. Time-resolved photoluminescence and photon autocorrelation measurements are used to prove the single photon character of the emission into the propagating waveguide mode. The results obtained demonstrate that such nanostructures can be used to realize an on-chip, highly directed single photon source with single mode spontaneous emision coupling efficiencies in excess of \\beta~85 % and the potential to reach maximum emission rates >1 GHz.

  16. A Bright Single Photon Source Based on a Diamond Nanowire

    CERN Document Server

    Babinec, T; Khan, M; Zhang, Y; Maze, J; Hemmer, P R; Loncar, M

    2009-01-01

    The development of a robust light source that emits one photon at a time is an outstanding challenge in quantum science and technology. Here, at the transition from many to single photon optical communication systems, fully quantum mechanical effects may be utilized to achieve new capabilities, most notably perfectly secure communication via quantum cryptography. Practical implementations place stringent requirements on the device properties, including fast and stable photon generation, efficient collection of photons, and room temperature operation. Single photon light emitting devices based on fluorescent dye molecules, quantum dots, nanowires, and carbon nanotube material systems have all been explored, but none have simultaneously demonstrated all criteria. Here, we describe the design, fabrication, and characterization of a bright source of single photons consisting of an individual Nitrogen-vacancy color center (NV center) in a diamond nanowire operating in ambient conditions. The nanowire plays a posit...

  17. Photonic wires and trumpets for ultrabright single photon sources

    DEFF Research Database (Denmark)

    Gérard, Jean-Michel Commisariat Energie Atomique

    2013-01-01

    Photonic wires have recently demonstrated very attractive assets in the field of high-efficiency single photon sources. After presenting the basics of spontaneous emission control in photonic wires, we compare the two possible tapering strategies that can be applied to their output end so as to tailor their radiation diagram in the far-field. We highlight the novel “photonic trumpet” geometry, which provides a clean Gaussian beam, and is much less sensitive to fabrication imperfections than the more common needle-like taper geometry. S4Ps based on a single QD in a PW with integrated bottom mirror and tapered tip display jointly a record-high efficiency (0.75±0.1 photon per pulse) and excellent single photon purity. Beyond single photon sources, photonic wires and trumpets appear as a very attractive resource for solid-state quantum optics experiments.

  18. Single Photon Avalanche Diodes: Towards the Large Bidimensional Arrays

    Directory of Open Access Journals (Sweden)

    Emilio Sciacca

    2008-08-01

    Full Text Available Single photon detection is one of the most challenging goals of photonics. In recent years, the study of ultra-fast and/or low-intensity phenomena has received renewed attention from the academic and industrial communities. Intense research activity has been focused on bio-imaging applications, bio-luminescence, bio-scattering methods, and, more in general, on several applications requiring high speed operation and high timing resolution. In this paper we present design and characterization of bi-dimensional arrays of a next generation of single photon avalanche diodes (SPADs. Single photon sensitivity, dark noise, afterpulsing and timing resolution of the single SPAD have been examined in several experimental conditions. Moreover, the effects arising from their integration and the readout mode have also been deeply investigated.

  19. Study of narrowband single photon emitters in polycrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Sandstrom, Russell G.; Shimoni, Olga; Martin, Aiden A.; Aharonovich, Igor, E-mail: igor.aharonovich@uts.edu.au [School of Physics and Advanced Materials, University of Technology, Sydney, P.O. Box 123, Broadway, New South Wales 2007 (Australia)

    2014-11-03

    Quantum information processing and integrated nanophotonics require robust generation of single photon emitters on demand. In this work, we demonstrate that diamond films grown on a silicon substrate by microwave plasma chemical vapor deposition can host bright, narrowband single photon emitters in the visible—near infra-red spectral range. The emitters possess fast lifetime (?several ns), absolute photostability, and exhibit full polarization at excitation and emission. Pulsed and continuous laser excitations confirm their quantum behaviour at room temperature, while low temperature spectroscopy is performed to investigate inhomogeneous broadening. Our results advance the knowledge of solid state single photon sources and open pathways for their practical implementation in quantum communication and quantum information processing.

  20. Witnessing trustworthy single-photon entanglement with local homodyne measurements.

    Science.gov (United States)

    Morin, Olivier; Bancal, Jean-Daniel; Ho, Melvyn; Sekatski, Pavel; D'Auria, Virginia; Gisin, Nicolas; Laurat, Julien; Sangouard, Nicolas

    2013-03-29

    Single-photon entangled states, i.e., states describing two optical paths sharing a single photon, constitute the simplest form of entanglement. Yet they provide a valuable resource in quantum information science. Specifically, they lie at the heart of quantum networks, as they can be used for quantum teleportation, swapped, and purified with linear optics. The main drawback of such entanglement is the difficulty in measuring it. Here, we present and experimentally test an entanglement witness allowing one to say whether a given state is path entangled and also that entanglement lies in the subspace, where the optical paths are each filled with one photon at most, i.e., refers to single-photon entanglement. It uses local homodyning only and relies on no assumption about the Hilbert space dimension of the measured system. Our work provides a simple and trustworthy method for verifying the proper functioning of future quantum networks. PMID:23581297

  1. Sequential thallium-201 myocardial perfusion studies after successful percutaneous transluminal coronary artery angioplasty: delayed resolution of exercise-induced scintigraphic abnormalities

    International Nuclear Information System (INIS)

    To characterize the sequential changes of myocardial perfusion scintigraphy in patients with coronary artery disease (CAD) after complete revascularization, 43 patients underwent exercise thallium-201 (201Tl) myocardial perfusion scintigraphy before and at 9 +/- 5 days, 3.3 +/- 0.6, and 6.8 +/- 1.2 months after percutaneous transluminal coronary angioplasty (PTCA). Only patients with single-vessel CAD, without previous myocardial infarction, and without evidence of restenosis at 6 to 9 months after PTCA were included. Perfusion scans were analyzed blindly with the use of a new quantitative method to define regional myocardial perfusion in the topographic distribution of each coronary artery, which was shown to be reproducible (r = .94 or higher and SEE of 7% or less, between repeated measures by one and two operators). At 4 to 18 days after PTCA, the mean treadmill walking time increased by 123 +/- 42 sec, mean exercise-induced ST segment depression decreased by 0.6 +/- 0.3 mm, group maximal heart rate increased by 20 +/- 9 beats/min, and group systolic blood pressure at peak exercise increased by 24 +/- 10 mm Hg, compared with pre-PTCA values (p less than .001). However, no group differences were noted in these variables between the three post-PTCA stages. Myocardial perfusion in the distribution of the affected (dilated) coronary artery, on the other hand, improved progressively. In the 45 degree left anterior oblique view for instance, myocardial perfusion increased at 9 days after PTCA (from 68 +/- 24% before PTCA to 91 +/- 9%, p less than .001) and at 3.3 months after PTCA (101 +/- 8%, p less than .05 vs 9 days after PTCA), but no further significant changes were seen at 6.8 months after PTCA (102 +/- 8%). Similar changes were noted in the other two views. No relationship between minor complications during PTCA and delayed improvement on the 201Tl was observed

  2. Interferometric Quantum-Nondemolition Single-Photon Detectors

    Science.gov (United States)

    Kok, Peter; Lee, Hwang; Dowling, Jonathan

    2007-01-01

    Two interferometric quantum-nondemolition (QND) devices have been proposed: (1) a polarization-independent device and (2) a polarization-preserving device. The prolarization-independent device works on an input state of up to two photons, whereas the polarization-preserving device works on a superposition of vacuum and single- photon states. The overall function of the device would be to probabilistically generate a unique detector output only when its input electromagnetic mode was populated by a single photon, in which case its output mode would also be populated by a single photon. Like other QND devices, the proposed devices are potentially useful for a variety of applications, including such areas of NASA interest as quantum computing, quantum communication, detection of gravity waves, as well as pedagogical demonstrations of the quantum nature of light. Many protocols in quantum computation and quantum communication require the possibility of detecting a photon without destroying it. The only prior single- photon-detecting QND device is based on quantum electrodynamics in a resonant cavity and, as such, it depends on the photon frequency. Moreover, the prior device can distinguish only between one photon and no photon. The proposed interferometric QND devices would not depend on frequency and could distinguish between (a) one photon and (b) zero or two photons. The first proposed device is depicted schematically in Figure 1. The input electromagnetic mode would be a superposition of a zero-, a one-, and a two-photon quantum state. The overall function of the device would be to probabilistically generate a unique detector output only when its input electromagnetic mode was populated by a single photon, in which case its output mode also would be populated by a single photon.

  3. Assessment of myocardial washout of Tc-99m-sestamibi in patients with chronic heart failure. Comparison with normal control

    International Nuclear Information System (INIS)

    In contrast to 201TlCl, 99mTc-sestamibi shows very slow myocardial clearance after its initial myocardial uptake. In the present study, myocardial washout of 99mTc-sestamibi was calculated in patients with non-ischemic chronic heart failure (CHF) and compared with biventricular parameters obtained from first-pass and ECG-gated myocardial perfusion SPECT data. After administration of 99mTc-sestamibi, 25 patients with CHF and 8 normal controls (NC) were examined by ECG-gated myocardial perfusion SPECT and planar data acquisition in the early and delayed (interval of 3 hours) phase. Left ventricular ejection fraction (LVEF, %), peak filling rate (PFR, sec-1), end-diastolic volume (LVEDV, ml) and end-systolic volume (LVESV, ml) were automatically calculated from the ECG-gated SPECT data. Myocardial washout rates over 3 hours were calculated from the early and delayed planar images. Myocardial washout rates in the CHF group (39.6±5.2%) were significantly higher than those in the NC group (31.2±5.5%, p99mTc-sestamibi is considered to be a novel marker for the diagnosis of myocardial damage in patients with chronic heart failure. (author)

  4. The clinical impact of thallium-201 reinjection for the detection of myocardial hibernation

    International Nuclear Information System (INIS)

    Thallium-201 reinjection improves detection of hibernating myocardium in about 30%-50% of persisting defects. The main goal of cardiac revascularization techniques is amelioration of clinical symptoms such as angina and dyspnoea; however, improvement in regional and global pump function is an additional and important target. The aim of this study was to investigate whether fill-in in the reinjection study is correlated with improved contractile function after treatment (percutaneous transluminal coronary angioplasty/aortocoronary bypass surgery). We studied 32 patients with coronary heart disease and impaired regional wall motion (RWM). RWM and ejection fraction (EF) were assessed by analysing ventriculographic images using the centreline method (values in standard deviations from mean values found in a healthy control group). Three 201Tl single-photon emission tomographic studies (stress, redistribution and reinjection) were performed prior to revascularization and analysed using a bull's-eye scheme. Patients were divided into two groups (group FI-=no fill-in, n=16; group FI+=fill-in, n=16). Fifty-six percent of all patients showed persisting defects, and 56% of these defects showed fill-in after reinjection. Fill-in in our patient group was independent of the size of the persisting defects. After revascularization RWM increased significantly in group FI+ (from -1.9 to 0.0 SD, P201Tl reinjection image can predict recovery of RWM and EF after revascularization and should be used in all patients with impaired RWM and persisting defects independent of their extent. (orig.). With 7 figs., 2 tabs

  5. Investigation of Hamamatsu H8500 phototubes as single photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, R. A.; Hoek, M.; Lucherini, V.; Mirazita, M.; Orlandi, A.; Anefalos Pereira, S.; Pisano, S.; Rossi, P.; Viticchie, A.; Witchger, A.

    2015-08-01

    We have investigated the response of a significant sample of Hamamatsu H8500 MultiAnode PhotoMultiplier Tubes (MAPMTs) as single photon detectors, in view of their use in a ring imaging Cherenkov counter for the CLAS12 spectrometer at the Thomas Jefferson National Accelerator Facility. For this, a laser working at 407.2nm wavelength was employed. The sample is divided equally into standard window type, with a spectral response in the visible light region, and UV-enhanced window type MAPMTs. The studies confirm the suitability of these MAPMTs for single photon detection in such a Cherenkov imaging application.

  6. Photon statistics characterization of a single-photon source

    International Nuclear Information System (INIS)

    In a recent experiment, we reported the time-domain intensity noise measurement of a single-photon source relying on single-molecule fluorescence control. In this paper, we present data processing starting from photocount timestamps. The theoretical analytical expression of the time-dependent Mandel parameter Q(T) of an intermittent single-photon source is derived from ON?OFF dynamics. Finally, source intensity noise analysis, using the Mandel parameter, is quantitatively compared with the usual approach relying on the time autocorrelation function, both methods yielding the same molecular dynamical parameters

  7. New Generation of Superconducting Nanowire Single-Photon Detectors

    Directory of Open Access Journals (Sweden)

    Goltsman G.N.

    2015-01-01

    Full Text Available We present an overview of recent results for new generation of infrared and optical superconducting nanowire single-photon detectors (SNSPDs that has already demonstrated a performance that makes them devices-of-choice for many applications. SNSPDs provide high efficiency for detecting individual photons while keeping dark counts and timing jitter minimal. Besides superior detection performance over a broad optical bandwidth, SNSPDs are also compatible with an integrated optical platform as a crucial requirement for applications in emerging quantum photonic technologies. By embedding SNSPDs in nanophotonic circuits we realize waveguide integrated single photon detectors which unite all desirable detector properties in a single device.

  8. MCP-PMT timing property for single photons

    International Nuclear Information System (INIS)

    We have measured the performance, especially the timing properties, of micro-channel plate photo-multiplier tubes (MCP-PMTs) by irradiating with single photons with/without a magnetic field. A time resolution of ?=30-35 ps was obtained for single photons under 1.5 T. With an MCP-PMT, a small time-of-flight counter, by means of Cherenkov light radiation instead of scintillation light has been prepared, and a time resolution ??10 ps was attained for a high-energy ?-beam by multiple photons

  9. Interferometric measurement of the helical mode of a single photon

    Energy Technology Data Exchange (ETDEWEB)

    Galvez, E J; Coyle, L E; Johnson, E; Reschovsky, B J, E-mail: egalvez@colgate.edu [Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346 (United States)

    2011-05-15

    We present measurements of the helical mode of single photons and do so by sending heralded photons through a Mach-Zehnder interferometer that prepares the light in a helical mode with topological charge one, and interferes it with itself in the fundamental non-helical mode. Masks placed after the interferometer were used to diagnose the amplitude and phase of the mode of the light. Auxiliary measurements verified that the light was in a non-classical state. The results are in good agreement with theory. The experiments demonstrate in a direct way that single photons carry the entire spatial helical-mode information.

  10. Interferometric measurement of the helical mode of a single photon

    International Nuclear Information System (INIS)

    We present measurements of the helical mode of single photons and do so by sending heralded photons through a Mach-Zehnder interferometer that prepares the light in a helical mode with topological charge one, and interferes it with itself in the fundamental non-helical mode. Masks placed after the interferometer were used to diagnose the amplitude and phase of the mode of the light. Auxiliary measurements verified that the light was in a non-classical state. The results are in good agreement with theory. The experiments demonstrate in a direct way that single photons carry the entire spatial helical-mode information.

  11. Single-photon heat conduction in electrical circuits

    CERN Document Server

    Jones, P J; Tan, K Y; Möttönen, M

    2011-01-01

    We study photonic heat conduction between two resistors coupled weakly to a single superconducting microwave cavity. At low enough temperature, the dominating part of the heat exchanged between the resistors is transmitted by single-photon excitations of the fundamental mode of the cavity. This manifestation of single-photon heat conduction should be experimentally observable with the current state of the art. Our scheme can possibly be utilized in remote interference-free temperature control of electric components and environment engineering for superconducting qubits coupled to cavities.

  12. Diagnosis of coronary artery disease by thallium-201 myocardial scintigraphy with intravenous infusion of SUNY4001 (adenosine) in effort angina pectoris. The clinical trial report at multi-center. Phase II

    International Nuclear Information System (INIS)

    Forty-four patients with effort angina pectoris were evaluated with SUNY4001 (adenosine) thallium-201 (201Tl) myocardial scintigraphy to detect coronary artery disease. These patients had single-vessel disease (?American Heart Association (AHA) 90% stenosis) in either right coronary artery (RCA) or left anterior descending (LAD). Adenosine was infused at the rate of 120 or 140 ?g/kg/min for six minutes. One hundred eleven MBq of 201Tl was injected after three minutes of the start of the infusion. The early and delayed images were obtained by SPECT imaging. The sensitivity was 94.7% at 120 ?g/kg/min and 84.2% at 140 ?g/kg/min. Adenosine 201Tl myocardial scintigraphy showed high accuracy for detecting significant coronary artery disease. Adverse reactions occurred in 77.3% of the patients. Regarding the rates of the adverse reactions, there was no significant difference between 120 and 140 ?g/kg/min. Major adverse reactions were Chest pain/discomfort (52.3%) and Flushing/Feeling of warmth (27.3%). No serious complication was observed at any infusion rate. Most of adverse reactions disappeared shortly. Only two patients required treatment for moderate chest pain, which, however, disappeared in several minutes. One of the treatments was merely the termination of adenosine infusion, and the other was sublingual spray of nitroglycerin. Adenosine infusion caused slight decrease in blood pressure and increase in heart rate. The hemodynamic changes resolved within several minutes after the adenosine infusion. Decrease in systolic blood pressure of more than 20 mmHg from the base level occurred in 26.1% and 52.4% at 120 and 140 ?g/kg/min infusion rate respectively. Therefore, the adenosine infusion at 120 ?g/kg/min should be considered safe and useful for the diagnosis of coronary artery disease by pharmacologic stress imaging. (author)

  13. Ultrafast all-optical switching by single photons

    CERN Document Server

    Volz, Thomas; Winger, Martin; Badolato, Antonio; Hennessy, Kevin J; Hu, Evelyn L; Imamoglu, Atac

    2011-01-01

    An outstanding goal in quantum optics is the realization of fast optical non-linearities at the single-photon level. Such non-linearities would allow for the realization of optical devices with new functionalities such as a single-photon switch/transistor or a controlled-phase gate, which could form the basis of future quantum optical technologies. While non-linear optics effects at the single-emitter level have been demonstrated in different systems, including atoms coupled to Fabry-Perot or toroidal micro-cavities, super-conducting qubits in strip-line resonators or quantum dots (QDs) in nano-cavities, none of these experiments so far has demonstrated single-photon switching on ultrafast timescales. Here, we demonstrate that in a strongly coupled QD-cavity system the presence of a single photon on one of the fundamental polariton transitions can turn on light scattering on a transition from the first to the second Jaynes-Cummings manifold with a switching time of 20 ps. As an additional device application, ...

  14. Quantum-state tomography of single-photon entangled states

    Science.gov (United States)

    Burch, E. T.; Henelsmith, C.; Larson, W.; Beck, M.

    2015-09-01

    We have performed quantum-state tomography on several different single-photon entangled states, that is, states in which a single photon is shared between two possible paths. We begin by doing a tomographic reconstruction of density matrices in the subspace where a single photon is shared by two spatial modes. In this subspace we are able to create high-fidelity, path-entangled states. Also within this subspace we use the Akaike information criterion and Monte Carlo simulations to help us estimate the amount and source of state drift in our system. We find that the primary state drift is due to phase drifts and fluctuations on the order of ? /400 in our experimental apparatus. We then use the single-photon subspace density matrices and further measurements to estimate density matrices in the larger space consisting of two modes containing up to one photon each. In this larger space we find that the concurrence of the density matrices is C ?0.08 and is greater than 0 by at least 45 standard deviations, indicating that our states are indeed entangled.

  15. Quantum cryptography based on realistic "single-photon" source.

    Czech Academy of Sciences Publication Activity Database

    Pe?ina, Jan; Haderka, Ond?ej; Soubusta, Jan

    Rochester : Optical Society of America, 2004 - (Bigelow, N.; Eberly, J.; Stroud, C.; Walmsley, I.), --- [International Conference on Quantum Information. Rochester (US), 10.06.2003-13.06.2003] R&D Projects: GA MŠk(CZ) LN00A015 Keywords : quantum cryptography * single-photon source Subject RIV: BH - Optics, Masers, Lasers

  16. Single photon emission computed tomography and other selected computer topics

    Energy Technology Data Exchange (ETDEWEB)

    Price, R.R.; Gilday, D.L.; Croft, B.Y. (eds.)

    1980-01-01

    This volume includes an overview of single photon emission computed tomography and numerous papers that describe and evaluate specific systems and techniques. Papers cover such topics as Auger cameras; seven-pinhole and slant-hole collimators; brain; cardiac; and gated blood-pool studies; and the BICLET and SPECT systems.

  17. Towards parallel control of multiple single-photon emitters

    OpenAIRE

    Brainis, Edouard; Lambert, K; Cielen, K.; Licari, Adrian; Emplit, Philippe; Hens, Zeger

    2011-01-01

    We present a method that allows us to control many solidstate emitters in parallel. We apply our method to core/shell quantum dots such as CdSe/CdS, which are known to be good single-photon emitters at room-temperature.

  18. How to Measure the Nonlocal Phase of a Single Photon

    OpenAIRE

    Erez, Noam

    2005-01-01

    The relative phase between spatially separated component waves of a single photon can be measured by joint interference with a second photon emitted by a known source. In the case of a single such phase (i.e. two component waves), the probability for a successful measurement is one half. This method can be implemented with current experimental techniques.

  19. Quantum interference of independently generated telecom-band single photons

    International Nuclear Information System (INIS)

    We report on high-visibility quantum interference of independently generated telecom O-band (1310 nm) single photons using standard single-mode fibers. The experimental data are shown to agree well with the results of simulations using a comprehensive quantum multimode theory without the need for any fitting parameter

  20. ?-SPAD: a new red sensitive single-photon counting module

    Science.gov (United States)

    Kell, Gerald; Bülter, Andreas; Wahl, Michael; Erdmann, Rainer

    2011-05-01

    Single Photon Avalanche Diodes (SPADs) are valuable detectors in numerous photon counting applications in the fields of quantum physics, quantum communication, astronomy, metrology and biomedical analytics. They typically feature a much higher photon detection efficiency than photomultiplier tubes, most importantly in the red to near-infrared range of the spectrum. Very often SPADs are combined with Time-Correlated Single Photon Counting (TCSPC) electronics for time-resolved data acquisition and the temporal resolution ("jitter") of a SPAD is therefore one of the key parameters for selecting a detector. We show technical data and first application results from a new type of red sensitive single photon counting module ("?-SPAD"), which is targeted at timing applications, most prominently in the area of Single Molecule Spectroscopy (SMS). The ?-SPAD photon counting module combines Laser Components' ultra-low noise VLoK silicon avalanche photodiode with specially developed quenching and readout electronics from PicoQuant. It features an extremely high photon detection efficiency of 75% at 670 nm and can be used to detect single photons over the 400 nm to 1100 nm wavelength range. The timing jitter of the output of the ?-SPAD can be as low as 350 ps, making it suitable for time-resolved fluorescence detection applications. First photon coincidence correlation measurements also show that the typical breakdown flash of SPADs is of comparably low intensity for these new SPADs.

  1. Transform-limited single photons from a single quantum dot

    Science.gov (United States)

    Kuhlmann, Andreas V.; Prechtel, Jonathan H.; Houel, Julien; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D.; Warburton, Richard J.

    2015-01-01

    Developing a quantum photonics network requires a source of very-high-fidelity single photons. An outstanding challenge is to produce a transform-limited single-photon emitter to guarantee that single photons emitted far apart in the time domain are truly indistinguishable. This is particularly difficult in the solid-state as the complex environment is the source of noise over a wide bandwidth. A quantum dot is a robust, fast, bright and narrow-linewidth emitter of single photons; layer-by-layer growth and subsequent nano-fabrication allow the electronic and photonic states to be engineered. This represents a set of features not shared by any other emitter but transform-limited linewidths have been elusive. Here, we report transform-limited linewidths measured on second timescales, primarily on the neutral exciton but also on the charged exciton close to saturation. The key feature is control of the nuclear spins, which dominate the exciton dephasing via the Overhauser field. PMID:26348157

  2. Transform-limited single photons from a single quantum dot

    Science.gov (United States)

    Kuhlmann, Andreas V.; Prechtel, Jonathan H.; Houel, Julien; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D.; Warburton, Richard J.

    2015-09-01

    Developing a quantum photonics network requires a source of very-high-fidelity single photons. An outstanding challenge is to produce a transform-limited single-photon emitter to guarantee that single photons emitted far apart in the time domain are truly indistinguishable. This is particularly difficult in the solid-state as the complex environment is the source of noise over a wide bandwidth. A quantum dot is a robust, fast, bright and narrow-linewidth emitter of single photons; layer-by-layer growth and subsequent nano-fabrication allow the electronic and photonic states to be engineered. This represents a set of features not shared by any other emitter but transform-limited linewidths have been elusive. Here, we report transform-limited linewidths measured on second timescales, primarily on the neutral exciton but also on the charged exciton close to saturation. The key feature is control of the nuclear spins, which dominate the exciton dephasing via the Overhauser field.

  3. Comparative study of dobutamine stress electron-beam computed tomography and exercise thallium scintigraphy in the diagnosis of patients with suspected coronary artery disease

    International Nuclear Information System (INIS)

    To evaluate the diagnostic value of dobutamine stress electron-beam computed tomography (EBCT) as compared with exercise stress thallium-201 single-photon emission computed tomography (201Tl-SPECT) for the detection of myocardial ischemia, 10 patients with proven or suspected coronary artery disease underwent both tests. Nine of the 10 patients also underwent coronary angiography. EBCT images were analyzed objectively to evaluate systolic wall thickening and analyzed segmentally to determine the distribution of the coronary arteries. Dobutamine stress EBCT revealed the presence of ischemia in 59 segments, whereas exercise stress 201Tl-SPECT revealed ischemia in 51 segments (agreement=73%). The advantage of dobutamine stress EBCT was demonstrated in the inferior/posterior segments as compared with the results of exercise stress 201Tl-SPECT. The overall sensitivity for detecting ischemic regions supplied by coronary arteries with significant stenosis (diameter stenosis >50%) was 83% for dobutamine stress EBCT and 79% for exercise stress 201Tl-SPECT (p=NS), with specificities of 75% and 82% (p=NS). Thus, dobutamine stress EBCT presents a reasonable alternative to exercise stress 201Tl-SPECT for the objective assessment of patients with suspected coronary artery disease. (author)

  4. Clinical results of invasive coronarographie and metabolic myocardial scintigraphie

    International Nuclear Information System (INIS)

    A survey of 204 isotope coronary/myocardial examinations using perfusion scintigraphic (n=133) and non-invasive metabolic methods (n=71) is presented (62 scanner-, 142 scintillation camera investigations). In 30-40% of the cases the perfusion method provides additional information to the laevo-coronary angiography finding. This applied to initial investigations and therapy plan (n=63) as well as evaluating the efficacy of coronary surgical procedures (various types of aorto-coronary venous by-pass (n=63), indirect myocardial revascularisation (n=7)). The most informative modification appears to be selective double (as well as mono-) nuclide filling of both coronary branches, since the anatomic classification and collateral regions are most accurately visualized here and the demonstration of the least the bypass region in the postoperative phase. In 71 cases of 201 Tl examinations, 41 of the 43 cases with confirmed myocardial infarcts and their sequelae were recognized with variable intensity, independent of the time after the actual infarct (including 5 cases of multiple infarction, 5 cardiac aneurysms). In the group of patients having coronary disease without a confirmed infarct (n=13), the distribution pattern was normal 3 times, while of the remaining patients who underwent angiography discrete to marked aberrations appeared in the angiograms corresponding to grade II in one case, to grade III in 2 cases and to grade IV in one case. The delineation from non-coronary heart disease appears to be problematic

  5. Myocardial uptake of thallium-201 in rat with cardiac hypertrophy

    International Nuclear Information System (INIS)

    The thallium-201 (TL) has been used in order to diagnose myocardial infarction and ischemia. Although it is well known that TL distributes in the myocardium in proportion to the distribution of coronary blood flow, the biological property of TL in the loaded myocardium remains unclear. We studied the myocardial uptake of TL in rat with cardiac hypertrophy. Experiments were performed in 30 anesthetized rats devided into 3 groups; control group (C,N=14), hypertrophy group (H,N=6) and diltiazem group (D, 0.3 mg/kg/min. IV. N=10). Cardiac hypertrophy was produced with the banding of the ascending aorta. Myocardial blood flow (MBF) was measured by microspheres labeled with Strontium-85. Cardiac weight was increased in H, and both MBF and TL uptake were proportionally increased. MBF was negatively correlated with the extraction fraction in C (r=-0.71), in H (r=-0.66) and in D (r=-0.85), and this relationship in H was significantly different from it in C (p<0.05), but not in D. From these results, we concluded that TL uptake in H is not always dependant on MBF and affected by the altered metabolism of hypertrophied myocardium. (author)

  6. All-Optical Routing of Single Photons by a One-Atom Switch Controlled by a Single Photon

    CERN Document Server

    Shomroni, Itay; Lovsky, Yulia; Bechler, Orel; Guendelman, Gabriel; Dayan, Barak

    2014-01-01

    The prospect of quantum networks, in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons. Here we realize the most basic unit of such a photonic circuit: a single-photon activated switch, capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single 87Rb atom coupled to a fiber-coupled, chip-based microresonator, and is completely all-optical, requiring no other fields beside the in-fiber single-photon pulses. Nonclassical statistics of the control pulse confirm that a single reflected photon toggles the switch from high reflection (65%) to high transmission (90%), with average of ~1.5 control photons per switching event (~3 including linear losses). The fact that the control and target photons are both in-fiber and practically identical makes this scheme compatible with scalable architectures for quantum information processing.

  7. Thallium-201: enhanced diagnostic specificity and sensitivity by computerized myocardial imaging and color display

    International Nuclear Information System (INIS)

    While Thallium-201 (Tl-201) myocardial scanning represents a universally accepted non-invasive diagnostic method for cardiac pathology, the study still presents significant interpretation problems due to the lack of definition in its graphic display. This can be circumvented by interfacing the scintillation camera to a dedicated computer connected with a color television screen. Storing the image in digital form enables its manipulation through two computerized processes: a) Enlargement and normalization of the image and b) Smoothing the display of the image. The result of these operations displayed on a scale of 16 colors, yields much better diagnostic accuracy and correlation with data obtained through clinical, electrocardiographic and angiography findings, than the conventional black and white (BW) images

  8. Effect of eating on thallium-201 myocardial redistribution after myocardial ischemia

    International Nuclear Information System (INIS)

    To determine whether eating a high-carbohydrate meal between initial and delayed postexercise thallium-201 (Tl-201) imaging affects detection of Tl-201 redistribution during exercise stress testing, 16 patients with stable angina performed 2 Tl-201 treadmill exercise stress tests within a 14-day interval. Immediately after initial postexercise imaging, patients either drank a commercially available instant breakfast preparation for the intervention test or drank an equivalent volume of water for the control test. Comparable exercise workloads were achieved by exercising patients to the same heart rate for both tests. The order of the 2 (intervention and control) tests were randomized. All patients had at least 1 region of Tl-201 myocardial redistribution on either their eating or control test scans, although only 7 of the 16 had positive treadmill exercise test responses. Forty-six regions showing Tl-201 myocardial redistribution were identified in all 144 regions examined. Significantly more of these regions were identified on control test scans than on eating test scans: 11 of 46 on both test scans, 6 of 46 only on eating test scans and 29 of 46 only on control scans (p less than 0.001). Consistent with results of the quantitative regional analysis, the percentage of Tl-201 clearance over 4 hours in the 46 Tl-201 myocardial redistribution regions was 39 +/- 8% for the eating tests and 29 +/- 8% for control tests (mean +/- standard deviation, p less than 0.003). In 4 patients diagnosis of transient ischemia would have been missed because their 14 Tl-201 myocardial redistribution regions were detected only on the control test scans

  9. Patients with a normal exercise thallium-201 myocardial scintigram: always a good prognosis?

    International Nuclear Information System (INIS)

    The prognostic value of a normal exercise thallium-201 scintigram was determined in 211 patients with a normal exercise and resting scintigram. Endpoints were sudden cardiac death, nonfatal acute myocardial infarction and coronary artery bypass grafting or percutaneous transluminal coronary angioplasty. Forty patients (19%) had a history of a previous myocardial infarction and 40 (19%) were known to have had a previous percutaneous transluminal coronary angioplasty or coronary artery bypass grafting. Sixty-four patients (31%) were on treatment with ?-blocking agents. After a mean follow-up period of 23.5 months, 22 patients had had a cardiac event (1 cardiac death, 6 myocardial infarction, 15 revascularization). For the total group, the 1-year event rate for cardiac death, myocardial infarction, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting was 7.0%. For cardiac death or myocardial infarction alone the event rate was 2.8%. The only parameter independently predictive for cardiac events was the regular use of ?-blocking agents. The high event rate in patients on ?-blocking treatment is partly due to the fact that these patients were more symptomatic for coronary artery disease. The sustained ?-adrenergic blockade in this patient group, even in patients advised to stop medication, was suspected to interfere with the results of 201Tl scintigraphy. Therefore, more attention should be paid to patient instruction regarding the discontinuation of medication before the test. (orig.)