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Sample records for brain single-photon emission

  1. Brain single photon emission computed tomography in neonates

    International Nuclear Information System (INIS)

    This study was designed to rate the clinical value of [123I]iodoamphetamine (IMP) or [99mTc] hexamethyl propylene amine oxyme (HM-PAO) brain single photon emission computed tomography (SPECT) in neonates, especially in those likely to develop cerebral palsy. The results showed that SPECT abnormalities were congruent in most cases with structural lesions demonstrated by ultrasonography. However, mild bilateral ventricular dilatation and bilateral subependymal porencephalic cysts diagnosed by ultrasound were not associated with an abnormal SPECT finding. In contrast, some cortical periventricular and sylvian lesions and all the parasagittal lesions well visualized in SPECT studies were not diagnosed by ultrasound scans. In neonates with subependymal and/or intraventricular hemorrhage the existence of a parenchymal abnormality was only diagnosed by SPECT. These results indicate that [123I]IMP or [99mTc]HM-PAO brain SPECT shows a potential clinical value as the neurodevelopmental outcome is clearly related to the site, the extent, and the number of cerebral lesions. Long-term clinical follow-up is, however, mandatory in order to define which SPECT abnormality is associated with neurologic deficit

  2. Brain single photon emission computed tomography in neonates

    Energy Technology Data Exchange (ETDEWEB)

    Denays, R.; Van Pachterbeke, T.; Tondeur, M.; Spehl, M.; Toppet, V.; Ham, H.; Piepsz, A.; Rubinstein, M.; Nol, P.H.; Haumont, D. (Free Universities of Brussels (Belgium))

    1989-08-01

    This study was designed to rate the clinical value of ({sup 123}I)iodoamphetamine (IMP) or ({sup 99m}Tc) hexamethyl propylene amine oxyme (HM-PAO) brain single photon emission computed tomography (SPECT) in neonates, especially in those likely to develop cerebral palsy. The results showed that SPECT abnormalities were congruent in most cases with structural lesions demonstrated by ultrasonography. However, mild bilateral ventricular dilatation and bilateral subependymal porencephalic cysts diagnosed by ultrasound were not associated with an abnormal SPECT finding. In contrast, some cortical periventricular and sylvian lesions and all the parasagittal lesions well visualized in SPECT studies were not diagnosed by ultrasound scans. In neonates with subependymal and/or intraventricular hemorrhage the existence of a parenchymal abnormality was only diagnosed by SPECT. These results indicate that ({sup 123}I)IMP or ({sup 99m}Tc)HM-PAO brain SPECT shows a potential clinical value as the neurodevelopmental outcome is clearly related to the site, the extent, and the number of cerebral lesions. Long-term clinical follow-up is, however, mandatory in order to define which SPECT abnormality is associated with neurologic deficit.

  3. Radiopharmaceuticals for single-photon emission computed tomography brain imaging.

    Science.gov (United States)

    Kung, Hank F; Kung, Mei-Ping; Choi, Seok Rye

    2003-01-01

    In the past 10 years, significant progress on the development of new brain-imaging agents for single-photon emission computed tomography has been made. Most of the new radiopharmaceuticals are designed to bind specific neurotransmitter receptor or transporter sites in the central nervous system. Most of the site-specific brain radiopharmaceuticals are labeled with (123)I. Results from imaging of benzodiazepine (gamma-aminobutyric acid) receptors by [(123)I]iomazenil are useful in identifying epileptic seizure foci and changes of this receptor in psychiatric disorders. Imaging of dopamine D2/D3 receptors ([(123)I]iodobenzamide and [(123)I]epidepride) and transporters [(123)I]CIT (2-beta-carboxymethoxy-3-beta(4-iodophenyl)tropane) and [(123)I]FP-beta-CIT (N-propyl-2-beta-carboxymethoxy-3-beta(4-iodophenyl)-nortropane has proven to be a simple but powerful tool for differential diagnosis of Parkinson's and other neurodegenerative diseases. A (99m)Tc-labeled agent, [(99m)Tc]TRODAT (technetium, 2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo [3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino] ethanethiolato(3-)]oxo-[1R-(exo-exo)]-), for imaging dopamine transporters in the brain has been successfully applied in the diagnosis of Parkinson's disease. Despite the fact that (123)I radiopharmaceuticals have been widely used in Japan and in Europe, clinical application of (123)I-labeled brain radiopharmaceuticals in the United States is limited because of the difficulties in supplying such agents. Development of (99m)Tc agents will likely extend the application of site-specific brain radiopharmaceuticals for routine applications in aiding the diagnosis and monitoring treatments of various neurologic and psychiatric disorders. PMID:12605353

  4. Evaluation of a 99Tcm bound brain scanning agent for single photon emission computed tomography

    DEFF Research Database (Denmark)

    Andersen, A R; Hasselbalch, S G; Paulson, O B;

    1986-01-01

    D,L HM-PAO-99Tcm (PAO) is a lipophilic tracer complex which is avidly taken up by the brain. We have compared the regional distribution of PAO with regional cerebral blood flow (CBF). CBF was measured by single photon emission computed tomography (SPECT) by Tomomatic 64 after 133Xe inhalation in 41...

  5. Statistical parametric mapping in brain single photon computed emission tomography after carbon monoxide intoxication.

    Science.gov (United States)

    Watanabe, N; Nohara, S; Matsuda, H; Sumiya, H; Noguchi, K; Shimizu, M; Tsuji, S; Kinuya, S; Shuke, N; Yokoyama, K; Seto, H

    2002-04-01

    The purpose of this retrospective study was to assess regional cerebral blood flow in patients after carbon monoxide intoxication by using brain single photon emission computed tomography and statistical parametric mapping. Eight patients with delayed neuropsychiatric sequelae and ten patients with no neuropsychiatric symptoms after carbon monoxide intoxication were studied with brain single photon emission tomography imaging with 99mTc-hexamethyl-propyleneamine oxime. Forty-four control subjects were also studied. We used the adjusted regional cerebral blood flow images in relative flow distribution (normalization of global cerebral blood flow for each subject to 50 ml x 100 g(-1) x min(-1) with proportional scaling) to compare these groups with statistical parametric mapping. Using this technique, significantly decreased regional cerebral blood flow was noted extensively in the bilateral frontal lobes as well as the bilateral insula and a part of the right temporal lobe in the patients with delayed neuropsychiatric sequelae as compared with normal volunteers (Pparametric mapping is a useful technique for highlighting differences in regional cerebral blood flow in patients following carbon monoxide intoxication as compared with normal volunteers. The selectively reduced blood flow noted in this investigation supports the contention that the decrease following carbon monoxide intoxication may be prolonged and further worsen in the frontal lobe. In addition, the present study may help to clarify the characteristics of the pathophysiological alteration underlying delayed neuropsychiatric sequelae.

  6. Brain blood flow studies with single photon emission computed tomography in patients with plateau waves

    International Nuclear Information System (INIS)

    The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem : a cross section 25 deg over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves. (author)

  7. Single-photon emission tomography.

    Science.gov (United States)

    Goffin, Karolien; van Laere, Koen

    2016-01-01

    Single-photon emission computed tomography (SPECT) is a functional nuclear imaging technique that allows visualization and quantification of different in vivo physiologic and pathologic features of brain neurobiology. It has been used for many years in diagnosis of several neurologic and psychiatric disorders. In this chapter, we discuss the current state-of-the-art of SPECT imaging of brain perfusion and dopamine transporter (DAT) imaging. Brain perfusion SPECT imaging plays an important role in the localization of the seizure onset zone in patients with refractory epilepsy. In cerebrovascular disease, it can be useful in determining the cerebrovascular reserve. After traumatic brain injury, SPECT has shown perfusion abnormalities despite normal morphology. In the context of organ donation, the diagnosis of brain death can be made with high accuracy. In neurodegeneration, while amyloid or (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) are the nuclear diagnostic tools of preference for early and differential diagnosis of dementia, perfusion SPECT imaging can be useful, albeit with slightly lower accuracy. SPECT imaging of the dopamine transporter system is widely available in Europe and Asia, but since recently also in the USA, and has been accepted as an important diagnostic tool in the early and differential diagnosis of parkinsonism in patients with unclear clinical features. The combination of perfusion SPECT (or FDG-PET) and DAT imaging provides differential diagnosis between idiopathic Parkinson's disease, Parkinson-plus syndromes, dementia with Lewy bodies, and essential tremor. PMID:27432669

  8. 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.)

  9. A study of cerebral perfusion using single photon emission computed tomography in neonates with brain lesions

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, J.; Contantinesco, A.; Brunot, B.; Messer, J. (Hospital Universitaire de Strasbourg (France))

    1994-03-01

    In this study the authors used a single photon emission computed tomography technique (SPECT) with radiolabelled [sup 99m]Tc HMPAO to assess cerebral perfusion in newborn infants with documented cerebral lesions and to determine to what extent brain SPECT might be useful in the neonatal period. A total of 15 newborn infants with the following cerebral pathologies were enrolled: severe parietal bilateral periventricular leucomalacia; moderate parietal bilateral PVL; intraventricular haemorrhage grade II with unilateral parietal parenchymal extension; cerebral infarction in the zone of middle cerebral artery; and post-haemorrhagic hydrocephalus. Follow-up was available in all infants. Alterations in cerebral perfusion were seen in only 12 of 15 infants and at the location of severe PVL, PE and CI. It was noted that the regions of diminished perfusion extended beyond the apparent extent of cerebral pathology delineated by ultrasound or magnetic resonance imaging. Markedly diminished perfusion was seen in one infant with hydrocephalus, which recovered following placement of ventriculo-peritoneal shunt. Regarding outcome, SPECT data failed to provide additional information than that of neuroradiological investigations. It is concluded that the use of SPECT, under these conditions, to assess alteration of cerebral perfusion in the neonatal period will not provide any additional information than that of neuroradiological investigations. 17 refs., 3 figs., 1 tab.

  10. Two Cases of Legionella pneumophila Pneumonia with Prolonged Neurologic Symptoms and Brain Hypoperfusion on Single-Photon Emission Computed Tomography

    Science.gov (United States)

    Miura, You; Seto, Akira; Kanazawa, Minoru; Nagata, Makoto

    2016-01-01

    Cerebral and cerebellar symptoms are frequently associated with Legionnaires' disease. However, corresponding brain lesions are difficult to demonstrate using either computed tomography (CT) or magnetic resonance imaging (MRI). We report here two patients with Legionella pneumophila pneumonia accompanied by prolonged neurologic symptoms. In contrast to brain CT and MRI, which failed to detect any abnormalities, single-photon emission computed tomography (SPECT) showed multiple sites of hypoperfusion within the brains of both patients. These cases suggest that vasculopathy, which is detectable by SPECT, might be one of the causes of neurologic symptoms in patients with Legionnaires' disease.

  11. Two Cases of Legionella pneumophila Pneumonia with Prolonged Neurologic Symptoms and Brain Hypoperfusion on Single-Photon Emission Computed Tomography.

    Science.gov (United States)

    Ohta, Hiromitsu; Yamazaki, Susumu; Miura, You; Seto, Akira; Kanazawa, Minoru; Nagata, Makoto

    2016-01-01

    Cerebral and cerebellar symptoms are frequently associated with Legionnaires' disease. However, corresponding brain lesions are difficult to demonstrate using either computed tomography (CT) or magnetic resonance imaging (MRI). We report here two patients with Legionella pneumophila pneumonia accompanied by prolonged neurologic symptoms. In contrast to brain CT and MRI, which failed to detect any abnormalities, single-photon emission computed tomography (SPECT) showed multiple sites of hypoperfusion within the brains of both patients. These cases suggest that vasculopathy, which is detectable by SPECT, might be one of the causes of neurologic symptoms in patients with Legionnaires' disease. PMID:27478660

  12. Two Cases of Legionella pneumophila Pneumonia with Prolonged Neurologic Symptoms and Brain Hypoperfusion on Single-Photon Emission Computed Tomography

    Directory of Open Access Journals (Sweden)

    Hiromitsu Ohta

    2016-01-01

    Full Text Available Cerebral and cerebellar symptoms are frequently associated with Legionnaires’ disease. However, corresponding brain lesions are difficult to demonstrate using either computed tomography (CT or magnetic resonance imaging (MRI. We report here two patients with Legionella pneumophila pneumonia accompanied by prolonged neurologic symptoms. In contrast to brain CT and MRI, which failed to detect any abnormalities, single-photon emission computed tomography (SPECT showed multiple sites of hypoperfusion within the brains of both patients. These cases suggest that vasculopathy, which is detectable by SPECT, might be one of the causes of neurologic symptoms in patients with Legionnaires’ disease.

  13. Brain perfusion single photon emission computed tomography in children after acute encephalopathy

    International Nuclear Information System (INIS)

    We studied single photon emission computed tomography (SPECT) of 15 children with acute encephalopathy after more than 1 year from the onset, using technetium-99 m-L, L-ethyl cystinate dimer (99mTc-ECD) and a three-dementional stereotaxic region of interest template. Regional cerebral blood flow was evaluated and divided in three groups according to the severity of disability: absent or mild, moderate, and severe. There was no abnormality on SPECT in the patients without disability or with mild disability. Diffuse hypoperfusion was shown in the groups with moderate and severe disability. The patients with severe disability showed hypoperfusion in the pericallosal, frontal and central areas which was more pronounced than in the patients with moderate disability. (author)

  14. Establishment of a brain perfusion single photon emission computed tomography database in children by statistical imaging analysis

    International Nuclear Information System (INIS)

    We made a 3-dimensional, 99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) database in children by a statistical analysis. We selected 52 individuals between 1 and 15 years of age whose brain SPECT and brain MRI findings were normal, and divided them into three age groups: 1-5, 6-10 and 11-15 years. By comparing databases obtained for each group, an age-dependent change of regional cerebral blood flow was investigated. The results showed that the relative blood flow increases in the frontal lobe and cerebeller hemisphere and decrease in the occipital lobe with increasing age, findings consistent with those of previous reports. This database enabled us to easily find 3-dimensional brain perfusion abnormality in individual patient by SPECT, and may help elucidate the pathophysiology of many brain disorders. (author)

  15. Effect of expression of P-glycoprotein on technetium-99m methoxyisobutylisonitrile single photon emission computed tomography of brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Yasushi; Matsumura, Akira; Nose, Tadao [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine

    2002-08-01

    The expression of P-glycoprotein was investigated imunohistochemically in 26 brain tumor tissues and compared with the findings of technetium-99m methoxyisobutylisonitrile single photon emission computed tomography ({sup 99m}Tc-MIBI SPECT) to clarify the effect of P-glycoprotein on the diagnostic accuracy. P-glycoprotein labeling index of both tumor cells and vascular endothelial cells showed no clear relationship with the findings of {sup 99m}Tc-MIBI SPECT imaging. Expression of P-glycoprotein has no effect on the diagnostic accuracy of {sup 99m}Tc-MIBI SPECT. (author)

  16. Metabolism of [123I]epidepride may affect brain dopamine D2 receptor imaging with single-photon emission tomography.

    Science.gov (United States)

    Bergström, K A; Yu, M; Kuikka, J T; Akerman, K K; Hiltunen, J; Lehtonen, J; Halldin, C; Tiihonen, J

    2000-02-01

    Iodine-123 labelled epidepride is a novel radiopharmaceutical for the study of cerebral dopamine D2 receptors using single-photon emission tomography (SPET). A lipophilic labelled metabolite of [123I]epidepride which may enter the brain and hamper the quantitation of receptors has been observed in human plasma. In the present study, gradient high-performance liquid chromatography (HPLC) was used to investigate the plasma concentration of the lipophilic labelled metabolite and its correlation to SPET imaging of striatal dopamine D2 receptors. A linear regression fit showed a negative correlation between the amount of the lipophilic labelled metabolite and the striatum to cerebellum ratio (n=16, R=-0.58, Pepidepride. PMID:10755727

  17. Metabolism of [123I]epidepride may affect brain dopamine D2 receptor imaging with single-photon emission tomography

    International Nuclear Information System (INIS)

    Iodine-123 labelled epidepride is a novel radiopharmaceutical for the study of cerebral dopamine D2 receptors using single-photon emission tomography (SPET). A lipophilic labelled metabolite of [123I]epidepride which may enter the brain and hamper the quantitation of receptors has been observed in human plasma. In the present study, gradient high-performance liquid chromatography (HPLC) was used to investigate the plasma concentration of the lipophilic labelled metabolite and its correlation to SPET imaging of striatal dopamine D2 receptors. A linear regression fit showed a negative correlation between the amount of the lipophilic labelled metabolite and the striatum to cerebellum ratio (n=16, R=-0.58, P2 receptors with SPET using [123I]epidepride. (orig.)

  18. Single Photon Emission Computed Tomography (SPECT)

    Science.gov (United States)

    ... Tools & Resources Stroke More Single Photon Emission Computed Tomography (SPECT) Updated:Sep 11,2015 What is a ... Heart Attack Myocardial Perfusion Imaging (MPI) Positron Emission Tomography (PET) Radionuclide Ventriculography, Radionuclide Angiography, MUGA Scan Heart ...

  19. Complementary single photon emission computed tomography of the brain: Xe-133 and iodoamphetamine

    International Nuclear Information System (INIS)

    Xe-133 and I-123 iodoamphetamin (IMP) emission computed tomography studies of 32 patients with neurologic (n = 7) or psychiatric (n = 25) diagnoses were used to determine whether the modalities yield complementary diagnostic information. The images, interpreted by two observers, differed in 15 (47%) cases. In schizophrenic patients, 11(61%) abnormalities were identified by Xe-133 imaging and 15(83%) by IMP. The abnormalities involved principally the frontal lobes and were identified in eight (73%) cases by Xe-133 imaging and in ten (67%) cases by IMP. In all four patients with arteriovenous malformations the imaging results were abnormal: Xe-133 showed increased flow while IMP revealed localized decreased activity in one patient. Imaging patterns for seizures, depression and psychoses also differed. Thus, Xe-133 and IMP appear complementary in their portrayal of brain function

  20. Evaluation of dysthymic disorder with technetium-99 m hexamethylpropylene amine oxime brain single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sarikaya, A.; Cermik, T.F. [Department of Nuclear Medicine, Trakya University, Faculty of Medicine, Edirne (Turkey); Karasin, E.; Abay, E. [Department of Psychiatry, Trakya University, Faculty of Medicine, Edirne (Turkey); Berkarda, S.

    1999-03-01

    Dysthymic disorder is a chronic disorder characterised by the presence of a depressed mood and is classified as a distinct category in DSM-IV, separately from major depression. Although brain imaging studies have been performed in major depressive disease, there have to date been no reports of such studies in dysthymic disorder. In this study 36 patients with dysthymic disorder were compared with 16 normal subjects using technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography. A relative blood flow ratio was calculated for each region of interest using the average tissue activity in the region divided by activity in the cerebellum. There were significant differences in the bilateral inferior frontal, bilateral parietal, right superior frontal and left posterior temporal regions in the patients with dysthymic disorder compared with the healthy controls. These findings support the hypothesis that the biological bases for dysthymic disorder and major depression are similar. Recognition of these regional abnormalities may have clinical utility in both the diagnosis and the treatment of dysthymic disorder. Further studies are needed to confirm our results and to assess the influence of treatment in patients with dysthymic disorder. (orig.) With 1 fig., 1 tab., 26 refs.

  1. Single photon emission computed tomography of the brain with a rotating gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Biersack, H.J.; Knopp, R.; Winkler, C.; Wappenschmidt, J.

    1981-08-01

    In 471 patients SPECT of the brain was performed in addition to conventional serial brain scintigraphy using a rotating gamma camera (GAMMATOME T 9000). 23 patients had tumorous lesions, 26 had vascular lesions, and 422 patients revealed normal brain findings. 5 of the 23 patients with tumorous lesion and 5 of the 12 patients with vascular lesion (anamnesis shorter than 4 weeks) showed positive SPECT results but false negative conventional brain scans. Specificity could be improved up to 98% (412 out of 422 patients) using SPECT and conventional scintigraphy.

  2. Single-photon emission computed tomography imaging for brain death donor counseling

    Science.gov (United States)

    Palaniswamy, Vijayanand; Sadhasivam, Suganya; Selvakumaran, Cibi; Jayabal, Priyadharsan; Ananth, S. R.

    2016-01-01

    Organ donation awareness is very poor in India. We have a high demand for transplant organs with poor supply. Apnea test is the confirmatory test for brain death in our country. The Transplantation of Human Organs Act does not support any ancillary testing for the confirmation of brain death in our country. Radionuclide scan is used widely in western countries as a confirmatory test. We in our institution used this as a tool for family counseling with successful conversion rate. PMID:27630461

  3. Clinical studies of brain functional images by motor activation using single photon emission computed tomography

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    Kawaguchi, Masahiro [Gifu Univ. (Japan). School of Medicine

    1998-09-01

    Thirty participants (10 normal controls; group A, 5 patients with brain tumors located near central sulcus without hemiparesis; group B, 10 patients with brain tumors located near central sulcus with hemiparesis; group C, and 5 patients with brain tumors besides the central regions with hemiparesis; group D) were enrolled. The images were performed by means of split-dose method with {sup 99m}Tc-ECD at rest condition (SPECT 1) and during hand grasping (SPECT 2). The activation SPECT were obtained by subtracting SPECT 1 from SPECT 2, and the functional mapping was made by the strict registration of the activation SPECT with 3D MRI. To evaluate the changes of CBF (%{Delta}CBF) of the sensorimotor and supplementary motor areas on the functional mapping, ratio of the average counts of SPECT 1 and SPECT 2 was calculated and statistically compared. The functional activation paradigms caused a significant increase of CBF in the sensorimotor area contra-lateral to the stimulated hand, although the sensorimotor area and the central sulcus in groups B and C were dislocated, compared with hemisphere of non-tumor side. The sensorimotor area ipsi-lateral to the stimulated hand could be detected in almost of all subjects. The supplementary motor area could be detected in all subjects. In group A, the average %{Delta}CBF were up 24.1{+-}4.3% in the contra-lateral sensorimotor area, and 22.3{+-}3.6% in the supplementary motor area, respectively. The average %{Delta}CBF in the contra-lateral sensorimotor area of group D was significantly higher than that of group A. The brain functional mapping by motor activation using SPECT could localize the area of cortical motor function in normal volunteers and patients with brain tumors. The changes of regional CBF by activation SPECT precisely assess the cortical motor function even in patients with brain tumors located near central sulcus. (K.H.)

  4. In vivo imaging of brain dopaminergic neurotransmission system in small animals with high-resolution single photon emission computed tomography

    International Nuclear Information System (INIS)

    High-resolution single photon emission computed tomography (SPECT) provides a unique capability to image the biodistribution of radiolabeled molecules in small laboratory animals. Thus, we applied the high-resolution SPECT to in vivo imaging of the brain dopaminergic neurotransmission system in common marmosets using two radiolabeled ligands, [123I]2β-carbomethoxy-3β-(4-iodophenyl)tropane (β-CIT) as a dopamine transporter(DAT) ligand and [123I]iodobenzamide (IBZM) as a dopamine D2 receptor (D2R) ligand. Specific images of the striatum, a region with a high density of dopaminergic synapses, were obtained at 240 min and 60 min after injection of [123I]β-CIT and [123I]IBZM, respectively. Furthermore, a significantly low accumulation of [123I]β-CIT in the striatum was observed in MPTP-treated animals compared with results for a control group, and a similar accumulation in the control group was observed with the pretreatment of deprenyl in the MPTP-treated animals. However, the striatal accumulation of [123I]IBZM showed no changes among the control, MPTP-treated, and deprenyl-MPTP-treated groups. These SPECT imaging results agreed well with those of DA concentration and motor behavior. Since MPTP destroys nigrostriatal dopamine nerves and produces irreversible neurodegeneration associated with Parkinsonian syndrome, SPECDT imaging data in this study demonstrated that deprenyl shows its neuroprotective effect on Parkinsonism by protecting against the destruction of presynaptic dopamine neutrons. (author)

  5. Dual-isotope single-photon emission computed tomography for dopamine and serotonin transporters in normal and parkinsonian monkey brains

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    Li, I-H. [Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei 114, Taiwan (China); Huang, W.-S. [Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, 114, Taiwan (China); Yeh, C.-B. [Department of Psychiatry, Tri-Service General Hospital, Taipei, 114, Taiwan (China); Liao, M.-H.; Chen, C.-C.; Shen, L.-H. [Division of Isotope Application, Institute of Nuclear Energy Research, Taoyaun, 325 Taiwan (China); Liu, J.-C. [Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan (China); Ma, K.-H. [Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan (China)], E-mail: kuohsing91@yahoo.com.tw

    2009-08-15

    Introduction: Parkinson's disease (PD) affects both dopaminergic and serotonergic systems. In this study, we simultaneously evaluated dopamine and serotonin transporters in primates using dual-isotope single-photon emission computed tomography (SPECT) imaging and compared the results with traditional single-isotope imaging. Methods: Four healthy and one 6-OHDA-induced PD monkeys were used for this study. SPECT was performed over 4 h after individual or simultaneous injection of [{sup 99m}Tc]TRODAT-1 (a dopamine transporter imaging agent) and [{sup 123}I]ADAM (a serotonin transporter imaging agent). Results: The results showed that the image quality and uptake ratios in different brain regions were comparable between single- and dual-isotope studies. The striatal [{sup 99m}Tc]TRODAT-1 uptake in the PD monkey was markedly lower than that in normal monkeys. The uptake of [{sup 123}I]ADAM in the midbrain of the PD monkey was comparable to that in the normal monkeys, but there were decreased uptakes in the thalamus and striatum of the PD monkey. Conclusions: Our results suggest that dual-isotope SPECT using [{sup 99m}Tc]TRODAT-1 and [{sup 123}I]ADAM can simultaneously evaluate changes in dopaminergic and serotonergic systems in a PD model.

  6. Single-photon emission tomography imaging of serotonin transporters in the nonhuman primate brain with [{sup 123}I]ODAM

    Energy Technology Data Exchange (ETDEWEB)

    Acton, P.D.; Mu, M.; Ploessl, K.; Hou, C.; Siciliano, M.; Zhuang Zhi-Ping; Oya, Shunichi; Choi, S.R. [Dept. of Radiology, University of Pennsylvania, Philadelphia, PA (United States); Kung, H.F. [Dept. of Radiology, University of Pennsylvania, Philadelphia, PA (United States); Department of Pharmacology, University of Pennsylvania, Philadelphia (United States)

    1999-10-01

    We have described previously a selective serotonin transporter (SERT) radioligand, [{sup 123}I]IDAM. We now report a similarly potent, but more stable IDAM derivative, 5-iodo-2-[2-[(dimethylamino)methyl]phenoxy]benzyl alcohol ([{sup 123}I]ODAM). The imaging characteristics of this radioligand were studied and compared against [{sup 123}I]IDAM. Dynamic sequences of single-photon emission tomography (SPET) scans were obtained on three female baboons after injection of 375 MBq of [{sup 123}I]ODAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 120 min after injection of [{sup 123}I]ODAM. Total integrated brain uptake of [{sup 123}I]ODAM was about 30% higher than [{sup 123}I]IDAM. After 60-120 min, the regional distribution of tracer within the brain reflected the characteristic distribution of SERT. Peak specific binding in the midbrain occurred 120 min after injection, with an equilibrium midbrain to cerebellar ratio of 1.50{+-}0.08, which was slightly lower than the value for [{sup 123}I]IDAM (1.80{+-} 0.13). Both the binding kinetics and the metabolism of [{sup 123}I]ODAM were slower than those of [{sup 123}I]IDAM. Following injection of a competing SERT ligand, (+)McN5652, the tracer exhibited washout from areas with high concentrations of SERT, with a dissociation kinetic rate constant k{sub off}=0.0085{+-}0.0028 min{sup -1} in the midbrain. Similar studies using nisoxetine and methylphenidate showed no displacement, consistent with its low binding affinity to norepinephrine and dopamine transporters, respectively. These results suggest that [{sup 123}I]ODAM is suitable for selective SPET imaging of SERT in the primate brain, with higher uptake and slower kinetics and metabolism than [{sup 123}I]IDAM, but also a slightly lower selectivity for SERT. (orig.)

  7. Quantification of dopamine transporters in the mouse brain using ultra-high resolution single-photon emission tomography

    International Nuclear Information System (INIS)

    Functional imaging of small animals, such as mice and rats, using ultra-high resolution positron emission tomography (PET) and single-photon emission tomography (SPET), is becoming a valuable tool for studying animal models of human disease. While several studies have shown the utility of PET imaging in small animals, few have used SPET in real research applications. In this study we aimed to demonstrate the feasibility of using ultra-high resolution SPET in quantitative studies of dopamine transporters (DAT) in the mouse brain. Four healthy ICR male mice were injected with (mean±SD) 704±154 MBq [99mTc]TRODAT-1, and scanned using an ultra-high resolution SPET system equipped with pinhole collimators (spatial resolution 0.83 mm at 3 cm radius of rotation). Each mouse had two studies, to provide an indication of test-retest reliability. Reference tissue kinetic modeling analysis of the time-activity data in the striatum and cerebellum was used to quantitate the availability of DAT. A simple equilibrium ratio of striatum to cerebellum provided another measure of DAT binding. The SPET imaging results were compared against ex vivo biodistribution data from the striatum and cerebellum. The mean distribution volume ratio (DVR) from the reference tissue kinetic model was 2.17±0.34, with a test-retest reliability of 2.63%±1.67%. The ratio technique gave similar results (DVR=2.03±0.38, test-retest reliability=6.64%±3.86%), and the ex vivo analysis gave DVR=2.32±0.20. Correlations between the kinetic model and the ratio technique (R2=0.86, P2=0.92, P=0.04) were both excellent. This study demonstrated clearly that ultra-high resolution SPET of small animals is capable of accurate, repeatable, and quantitative measures of DAT binding, and should open up the possibility of further studies of cerebral binding sites in mice using pinhole SPET. (orig.)

  8. Induced arousal following zolpidem treatment in a vegetative state after brain injury in 7 cases Analysis using visual single photon emission computerized tomography and digitized cerebral state monitor

    Institute of Scientific and Technical Information of China (English)

    Bo Du; Aijun Shan; Di Yang; Wei Xiang

    2008-01-01

    BACKGROUND: Several studies have reported the use of zolpidem for induced arousal after permanent vegetative states. However, changes in brain function and EMG after zolpidem treatment requires further investigation. OBJECTIVE: To investigate the effect of zolpidem, an unconventional drug, on inducing arousal in patients in a permanent vegetative state after brain injury using visual single photon emission computerized tomography and digitized cerebral state monitor. DESIGN: A self-controlled observation. SETTING: Shenzhen People's Hospital.PARTICIPANTS: Seven patients in a permanent vegetative state were selected from the Department of Neurosurgery, Shenzhen People's Hospital from March 2005 to May 2007. The group included 5 males and 2 females, 24–55 years of age, with a mean age of 38.5 years. All seven patients had been in a permanent vegetative statement for at least six months. The patient group included three comatose patients, who had sustained injuries to the cerebral cortex, basal ganglia, or thalamus in motor vehicle accidents, and four patients, who had suffered primary/secondary brain stem injury. Informed consents were obtained from the patients’ relatives. METHODS: The patients brains were imaged by 99Tcm ECD single photon emission computerized tomography prior to treatment with zolpidem [Sanofi Winthrop Industrie, France, code number approved by the State Food & Drug Administration (SFDA) J20040033, specification 10 mg per tablet. At 8:00 p.m., 10 mg zolpidem was dissolved with distilled water and administered through a nasogastric tube at 1 hour before and after treatment and 1 week following treatment, respectively. Visual analysis of cerebral perfusion changes in the injured brain regions before and after treatment was performed. Simultaneously, three monitoring parameters were obtained though a cerebral state monitor, which included cerebral state index, electromyographic index, and burst suppression index. MAIN OUTCOME MEASURES: Comparison

  9. Metabolism of [{sup 123}I]epidepride may affect brain dopamine D{sub 2} receptor imaging with single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, K.A.; Yu, M.; Kuikka, J.T.; Aakerman, K.K. [Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio (Finland); Hiltunen, J. [MAP Medical Technologies Oy, Tikkakoski (Finland); Lehtonen, J. [Department of Psychiatry, University of Kuopio (Finland); Halldin, C. [Karolinska Institute, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Hospital, Stockholm (Sweden); Tiihonen, J. [Department of Forensic Psychiatry, University of Kuopio, Niuvanniemi Hospital, Kuopio (Finland)

    2000-02-01

    Iodine-123 labelled epidepride is a novel radiopharmaceutical for the study of cerebral dopamine D{sub 2} receptors using single-photon emission tomography (SPET). A lipophilic labelled metabolite of [{sup 123}I]epidepride which may enter the brain and hamper the quantitation of receptors has been observed in human plasma. In the present study, gradient high-performance liquid chromatography (HPLC) was used to investigate the plasma concentration of the lipophilic labelled metabolite and its correlation to SPET imaging of striatal dopamine D{sub 2} receptors. A linear regression fit showed a negative correlation between the amount of the lipophilic labelled metabolite and the striatum to cerebellum ratio (n=16, R=-0.58, P<0.02), suggesting that plasma metabolite analysis is essential when imaging dopamine D{sub 2} receptors with SPET using [{sup 123}I]epidepride. (orig.)

  10. Striatal and extrastriatal imaging of dopamine D{sub 2}receptors in the living human brain with [ {sup 123}I]epidepride single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kuikka, J.T. [Department of Clinical Physiology, Kuopio University Hospital, Kuopio (Finland); Aakerman, K.K. [Department of Clinical Physiology, Kuopio University Hospital, Kuopio (Finland); Hiltunen, J. [MAP Medical Technologies Inc., Tikkakoski (Finland); Bergstroem, K.A. [Department of Clinical Physiology, Kuopio University Hospital, Kuopio (Finland); Raesaenen, P. [Department of Forensic Psychiatry, University of Kuopio and Niuvanniemi Hospital, Kuopio (Finland); Vanninen, E. [Department of Clinical Physiology, Kuopio University Hospital, Kuopio (Finland); Halldin, C. [Karolinska Institutet, Department of Clinical Neuroscience, Karolinska Hospital, Stockholm (Sweden); Tiihonen, J. [Department of Forensic Psychiatry, University of Kuopio and Niuvanniemi Hospital, Kuopio (Finland)

    1997-05-01

    The iodine-123 labelled ligand benzamide epidepride was evaluated as a probe for in vivo imaging of striatal and extrastriatal dopamine D{sub 2}receptor sites in the human brain. Four healthy males were imaged with a high-resolution single-photon emission tomography scanner. Striatal radioactivity peaked at 3 h after injection. The specific binding in the striatum was 0.91 {+-}0.03 at 3 h and this ratio steadily increased with time. Extrastriatal radioactivity was highest in the thalamus, in the midbrain and in the temporal cortex, and peaked at 45-60 min after injection of tracer. A smaller amount of radioactivity was found in the parietal, frontal and occipital cortices. Two radioactive metabolites were observed, of which one was more lipophilic than the parent compound. The radiation burden to the patient was 0.035 mSv/MBq (effective dose equivalent). The preliminary results showed that [ {sup 123}I]epidepride can be used for imaging striatal and extrastriatal dopamine D {sub 2}receptor sites in the living human brain. (orig.). With 5 figs., 1 tab.

  11. Striatal and extrastriatal imaging of dopamine D2 receptors in the living human brain with [123I]epidepride single-photon emission tomography.

    Science.gov (United States)

    Kuikka, J T; Akerman, K K; Hiltunen, J; Bergström, K A; Räsänen, P; Vanninen, E; Halldin, C; Tiihonen, J

    1997-05-01

    The iodine-123 labelled ligand benzamide epidepride was evaluated as a probe for in vivo imaging of striatal and extrastriatal dopamine D2 receptor sites in the human brain. Four healthy males were imaged with a high-resolution single-photon emission tomography scanner. Striatal radioactivity peaked at 3 h after injection. The specific binding in the striatum was 0.91+/-0.03 at 3 h and this ratio steadily increased with time. Extrastriatal radioactivity was highest in the thalamus, in the midbrain and in the temporal cortex, and peaked at 45-60 min after injection of tracer. A smaller amount of radioactivity was found in the parietal, frontal and occipital cortices. Two radioactive metabolites were observed, of which one was more lipophilic than the parent compound. The radiation burden to the patient was 0.035 mSv/MBq (effective dose equivalent). The preliminary results showed that [123I]epidepride can be used for imaging striatal and extrastriatal dopamine D2 receptor sites in the living human brain. PMID:9142727

  12. Striatal and extrastriatal imaging of dopamine D2receptors in the living human brain with [ 123I[epidepride single-photon emission tomography

    International Nuclear Information System (INIS)

    The iodine-123 labelled ligand benzamide epidepride was evaluated as a probe for in vivo imaging of striatal and extrastriatal dopamine D2receptor sites in the human brain. Four healthy males were imaged with a high-resolution single-photon emission tomography scanner. Striatal radioactivity peaked at 3 h after injection. The specific binding in the striatum was 0.91 ±0.03 at 3 h and this ratio steadily increased with time. Extrastriatal radioactivity was highest in the thalamus, in the midbrain and in the temporal cortex, and peaked at 45-60 min after injection of tracer. A smaller amount of radioactivity was found in the parietal, frontal and occipital cortices. Two radioactive metabolites were observed, of which one was more lipophilic than the parent compound. The radiation burden to the patient was 0.035 mSv/MBq (effective dose equivalent). The preliminary results showed that [ 123I[epidepride can be used for imaging striatal and extrastriatal dopamine D 2receptor sites in the living human brain. (orig.). With 5 figs., 1 tab

  13. Evaluation of intracranial space-occupying lesion with Tc99m-glucoheptonate brain single photon emission computed tomography in treatment-naïve patients

    Directory of Open Access Journals (Sweden)

    Jaiswal S

    2009-01-01

    Full Text Available Background : Glucoheptonate is a glucose analog with strong affinity for neoplastic brain tissues. Though extensively used as a tracer for detection of brain tumor recurrence, it′s utility for characterization of intracranial lesions as neoplastic or otherwise has not been evaluated in treatment-naοve patients. Aim : The study was conducted to determine if glucoheptonate has sufficient specificity for neoplastic lesions of brain so that it can be utilized as a single photon emission computed tomography (SPECT-tracer for differentiating neoplastic intracranial lesions from non-neoplastic ones in treatment-naοve patients. Settings and Design : A cross-sectional analysis of treatment-naοve patients with intracranial space-occupying lesion done in a tertiary care hospital. Materials and Methods : Fifty-four consecutive patients with clinical and radiological features of space-occupying lesion were included in this study. Glucoheptonate brain SPECT was performed before any definitive therapeutic intervention. Histopathological verification of diagnosis was obtained in all cases. Statistical Analysis Used : Descriptive statistics and student′s ′t′ test. Result : Increased glucoheptonate uptake over the site of radiological lesion was noted in 41 patients and no uptake was noticed in 13 patients. Histopathology of 12 out of the 13 glucoheptonate non-avid lesions turned out to be non-neoplastic lesion; however, one lesion was reported as a Grade-2 astrocytoma. Histology from all the glucoheptonate concentrating lesions was of mitotic pathology. The sensitivity, specificity and accuracy of glucoheptonate for neoplastic lesion was 97.6%, 100% and 98.1%. Conclusions : Glucoheptonate has high degree of specificity for neoplastic tissues of brain and may be used as a tracer for SPECT study to differentiate neoplastic intracranial lesions from non-neoplastic ones.

  14. 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.

  15. Perfusion impairments in infantile autism on technetium-99m ethyl cysteinate dimer brain single-photon emission tomography: comparison with findings on magnetic resonance imaging

    International Nuclear Information System (INIS)

    The neuro-anatomical substrate of autism has been the subject of detailed investigation. Because previous studies have not demonstrated consistent and specific neuro-imaging findings in autism and most such studies have been performed in adults and school-aged children, we performed a retrospective review in young children in search of common functional and anatomical abnormalities with brain single-photon emission tomography (SPET) using technetium-99m ethyl cysteinate dimer (ECD) and correlative magnetic resonance imaging (MRI). The patient population was composed of 23 children aged 28-92 months (mean: 54 months) who met the diagnostic criteria of autism as defined in the DSM-IV and CARS. Brain SPET was performed after intravenous injection of 185-370 MBq of 99mTc-ECD using a brain-dedicated annular crystal gamma camera. MRI was performed in all patients, including T1, T2 axial and T1 sagittal sequences. SPET data were assessed visually. Twenty patients had abnormal SPET scans revealing focal areas of decreased perfusion. Decreased perfusion of the cerebellar hemisphere (20/23), thalami (19/23), basal ganglia (5/23) and posterior parietal (10/23) and temporal (7/23) areas were noted on brain SPET. By contrast all patients had normal MRI findings without evidence of abnormalities of the cerebellar vermis, cerebellar hemisphere, thalami, basal ganglia or parietotemporal cortex. In conclusion, extensive perfusion impairments involving the cerebellum, thalami and parietal cortex were found in this study. SPET may be more sensitive in reflecting the pathophysiology of autism than MRI. However, further studies are necessary to determine the significance of thalamic and parietal perfusion impairment in autism. (orig.)

  16. A technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography study in adolescent patients with major depressive disorder

    Energy Technology Data Exchange (ETDEWEB)

    Tutus, A. [Department of Nuclear Medicine, Erciyes University School of Medicine, Kayseri (Turkey); Kibar, M. [Department of Nuclear Medicine, Cukurova University School of Medicine, Kayseri (Turkey); Sofuoglu, S.; Basturk, M.; Goenuel, A.S. [Department of Psychiatry, Erciyes University School of Medicine, Kayseri (Turkey)

    1998-06-01

    We have not encountered any brain single-photon emission tomography (SPET) study performed in adolescent depressed patients in the literature. Therefore, we used technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) brain SPET in adolescent patients with major depressive disorder (MDD) to examine the possible changes in cerebral perfusion and the possible association between perfusion indices and clinical variables. Fourteen adolescent out-patients (nine females, five males; mean{+-}SD age: 13.11{+-}1.43 years; range: 11-15 years) fulfilling the DSM-IV criteria for MDD and 11 age-matched healthy control subjects (six females, five males; mean{+-}SD age: 13.80{+-}1.60 years; range: 12-15 years) were included in the study. {sup 99}Tc-HMPAO brain SPET was performed twice in the patient group and once in the control group. The first SPET investigation was performed under non-medicated conditions and the second was performed after depressive symptoms had subsided. A relative perfusion index (PI) was calculated as the ratio of regional cortical activity to the whole brain activity. We found significant differences between the PI values of the untreated depressed patients and those of the controls, indicating relatively reduced perfusion in the left anterofrontal and left temporal cortical areas. No significant differences in regional PI values were found between the remitted depressed patients and the controls. Our study suggests that adolescent patients with MDD may have regional cerebral blood flow deficits in frontal regions and a greater anterofrontal right-left perfusion asymmetry compared with normal subjects. The fact that these abnormalities in perfusion indices have a trend toward normal values with symptomatic improvement suggests that they may be state-dependent markers for adolescent MDD. (orig.) With 3 figs., 2 tabs., 37 refs.

  17. Perfusion impairments in infantile autism on technetium-99m ethyl cysteinate dimer brain single-photon emission tomography: comparison with findings on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Y.H.; Lee, J.D.; Yoon, P.H.; Kim, D.I. [Division of Nuclear Medicine, Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Lee, H.B.; Shin, Y.J. [Department of Psychiatry, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1999-03-01

    The neuro-anatomical substrate of autism has been the subject of detailed investigation. Because previous studies have not demonstrated consistent and specific neuro-imaging findings in autism and most such studies have been performed in adults and school-aged children, we performed a retrospective review in young children in search of common functional and anatomical abnormalities with brain single-photon emission tomography (SPET) using technetium-99m ethyl cysteinate dimer (ECD) and correlative magnetic resonance imaging (MRI). The patient population was composed of 23 children aged 28-92 months (mean: 54 months) who met the diagnostic criteria of autism as defined in the DSM-IV and CARS. Brain SPET was performed after intravenous injection of 185-370 MBq of {sup 99m}Tc-ECD using a brain-dedicated annular crystal gamma camera. MRI was performed in all patients, including T1, T2 axial and T1 sagittal sequences. SPET data were assessed visually. Twenty patients had abnormal SPET scans revealing focal areas of decreased perfusion. Decreased perfusion of the cerebellar hemisphere (20/23), thalami (19/23), basal ganglia (5/23) and posterior parietal (10/23) and temporal (7/23) areas were noted on brain SPET. By contrast all patients had normal MRI findings without evidence of abnormalities of the cerebellar vermis, cerebellar hemisphere, thalami, basal ganglia or parietotemporal cortex. In conclusion, extensive perfusion impairments involving the cerebellum, thalami and parietal cortex were found in this study. SPET may be more sensitive in reflecting the pathophysiology of autism than MRI. However, further studies are necessary to determine the significance of thalamic and parietal perfusion impairment in autism. (orig.) With 2 figs., 1 tab., 33 refs.

  18. A technetium-99m hexamethylpropylene amine oxime brain single-photon emission tomography study in adolescent patients with major depressive disorder

    International Nuclear Information System (INIS)

    We have not encountered any brain single-photon emission tomography (SPET) study performed in adolescent depressed patients in the literature. Therefore, we used technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) brain SPET in adolescent patients with major depressive disorder (MDD) to examine the possible changes in cerebral perfusion and the possible association between perfusion indices and clinical variables. Fourteen adolescent out-patients (nine females, five males; mean±SD age: 13.11±1.43 years; range: 11-15 years) fulfilling the DSM-IV criteria for MDD and 11 age-matched healthy control subjects (six females, five males; mean±SD age: 13.80±1.60 years; range: 12-15 years) were included in the study. 99Tc-HMPAO brain SPET was performed twice in the patient group and once in the control group. The first SPET investigation was performed under non-medicated conditions and the second was performed after depressive symptoms had subsided. A relative perfusion index (PI) was calculated as the ratio of regional cortical activity to the whole brain activity. We found significant differences between the PI values of the untreated depressed patients and those of the controls, indicating relatively reduced perfusion in the left anterofrontal and left temporal cortical areas. No significant differences in regional PI values were found between the remitted depressed patients and the controls. Our study suggests that adolescent patients with MDD may have regional cerebral blood flow deficits in frontal regions and a greater anterofrontal right-left perfusion asymmetry compared with normal subjects. The fact that these abnormalities in perfusion indices have a trend toward normal values with symptomatic improvement suggests that they may be state-dependent markers for adolescent MDD. (orig.)

  19. Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients Correlation with disease severity and symptom factors

    Institute of Scientific and Technical Information of China (English)

    Heeyoung Kim; In Joo Kim; Seong-Jang Kim; Sang Heon Song; Kyoungjune Pak; Keunyoung Kim

    2012-01-01

    This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients (16 males, 11 females) with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pallidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity (total scores of Hamilton Depression Rating Scale) was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients.

  20. Brain MRI and single photon emission computed tomography in severe athetotic cerebral palsy. A comparative study with mental and motor disorders

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Kazutaka; Tsuzura, Shigenobu [Metropolitan Medical Center of the Severely Handicapped, Fuchu, Tokyo (Japan); Matsuda, Hiroshi

    1995-07-01

    Single photon emission computed tomography (SPECT) using N-isopropyl-p-[{sup 123}I]-iodoamphetamine ({sup 123}I-IMP) was performed in twelve patients with severe athetotic cerebral palsy (Ath; 5 males and 7 females) who had both motor delay (unable to move) and mental retardation (I.Q, or D.Q, below 30). The neuroimaging findings of those patients were compared with those of patients mental and motor disorders. In five caes suffering from neonatal asphyxia, SPECT demonstrated a decreased regional cerebral blood flow (rCBF) in corpus striatum, thalamus, orbitofrontal areas, pericentral gyrus areas, prefrontal areas and medial temporal areas. In seven cases suffering from neonatal jaundice, SPECT demonstrated a decreased rCBF in orbito-frontal areas, prefrontal areas and medial temporal areas. SPECT showed hypoperfusion of peri-central gyrus areas in cases with complications of spastic palsy. The decreased rCBF in medial temporal areas mostly corresponded to an alteration in hippocampal formation as assessed by magnetic resonance imaging (MRI). Cases with hypoperfusion of bilateral medial temporal areas showed a lower score of language understanding than those with the unilateral damage. In cases with hypofusion of bilateral prefrontal areas and bilateral medial temporal areas, the grade of understanding of language was almost below 12 months. In cases with hypoperfusion of orbitofrontal areas, psychomotor hypersensitivity had been observed. Those results suggest that IMP-SPECT and MRI of the brain is useful tool for neurological assessment in handicapped patients with athetotic cerebral palsy. (author).

  1. Brain MRI and single photon emission computed tomography in severe athetotic cerebral palsy. A comparative study with mental and motor disorders

    International Nuclear Information System (INIS)

    Single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) was performed in twelve patients with severe athetotic cerebral palsy (Ath; 5 males and 7 females) who had both motor delay (unable to move) and mental retardation (I.Q, or D.Q, below 30). The neuroimaging findings of those patients were compared with those of patients mental and motor disorders. In five caes suffering from neonatal asphyxia, SPECT demonstrated a decreased regional cerebral blood flow (rCBF) in corpus striatum, thalamus, orbitofrontal areas, pericentral gyrus areas, prefrontal areas and medial temporal areas. In seven cases suffering from neonatal jaundice, SPECT demonstrated a decreased rCBF in orbito-frontal areas, prefrontal areas and medial temporal areas. SPECT showed hypoperfusion of peri-central gyrus areas in cases with complications of spastic palsy. The decreased rCBF in medial temporal areas mostly corresponded to an alteration in hippocampal formation as assessed by magnetic resonance imaging (MRI). Cases with hypoperfusion of bilateral medial temporal areas showed a lower score of language understanding than those with the unilateral damage. In cases with hypofusion of bilateral prefrontal areas and bilateral medial temporal areas, the grade of understanding of language was almost below 12 months. In cases with hypoperfusion of orbitofrontal areas, psychomotor hypersensitivity had been observed. Those results suggest that IMP-SPECT and MRI of the brain is useful tool for neurological assessment in handicapped patients with athetotic cerebral palsy. (author)

  2. Clinical usefulness of scatter and attenuation correction for brain single photon emission computed tomography (SPECT) in pediatrics

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Itaru; Doi, Kenji; Komori, Tsuyoshi; Hou, Nobuyoshi; Tabuchi, Koujirou; Matsui, Ritsuo; Sueyoshi, Kouzou; Utsunomiya, Keita; Narabayashi, Isamu [Osaka Medical Coll., Takatsuki (Japan)

    1998-01-01

    This investigation was undertaken to study clinical usefulness of scatter and attenuation correction (SAC) of brain SPECT in infants to compare the standard reconstruction (STD). The brain SPECT was performed in 31 patients with 19 epilepsy, 5 cerebro-vascular disease, 2 brain tumor, 3 meningitis, 1 hydrocephalus and psychosis (mean age 5.0{+-}4.9 years old). Many patients was necessary to be injected sedatives for restraining body motion after Technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) was injected at the convulsion or rest. Brain SPECT data were acquired with triple detector gamma camera (GCA-9300 Toshiba Japan). These data were reconstructed by filtered backprojection after the raw data were corrected by triple energy windows method of scatter correction and Chang filtered method of attenuation correction. The same data was reconstructed by filtered backprojection without these corrections. Both SAC and STD SPECT images were analyzed by the visual interpretation. The uptake ratio of cerebral basal nuclei was calculated by the counts of the thalamus or lenticular nuclei divided by the cortex. All images of SAC method were excellent than that of STD method. The thalamic uptake ratio in SAC method was higher than that of STD method (1.22{+-}0.09>0.87{+-}0.22 p<0.01). The lenticular nuclear uptake ratio in SAC method was higher than that of STD method (1.26{+-}0.15>1.02{+-}0.16 p<0.01). Transmission scan is the most suitable method of absorption correction. But the transmission scan is not adequate for examination of children, because this scan needs a lot of time and the infants are exposed by the line source radioisotope. It was concluded that these scatter and absorption corrections were most suitable method for brain SPECT in pediatrics. (author)

  3. Importance of computerized tomography by single photon emission of brain perfusion in the diagnosis and prognostic of migraines

    International Nuclear Information System (INIS)

    The objective of this investigation was to establish the usefulness of ECD-99mTc brain perfusion SPECT in the evaluation of the diagnosis of functional alterations of Vascular Headaches of migrainous origin and to determine the changes in regional cerebral blood flow (FSCr) during the headache phase. A population of 21 female patients, 5 controls, of the same age and sex, aged between 20 and 76 years, with clinical evidence of headache with or without aura, with a duration of 8 to 72 hours, pulsating pain, associated to nausea, photophobia, phonophobia, that does not resolve with common analgesics and characterized by increase of the pain with physical activity. Brain perfusion SPECT was practiced on them at the moment of crisis, independent of the presence of aura or pain, and without crisis. ECD-99mTc was administered at a dose of 925 to 1110 MBq. Images were analyzed by the semi quantification method. SPECT detected 13 hypo-captures on the 16 patients studied. With a 81% sensitivity and 100% specificity, with a precision value of 86%. Analysis through X Binomial Aleatory Variable showed a precision of 90% (p= < 0,023) for the isotopic test, with a significance level of 5%. In conclusion, the results of this study confirm that brain SPECT is a neuroimaging technique capable of identifying migrainous patients, being able to reevaluate the type of hypo perfusion that each patient has, during crisis or out of crisis, and correlate the cortical perfusion deficits (Au)

  4. Differences in cerebral perfusion deficits in mild traumatic brain injury and depression using single photon emission computed tomography

    Directory of Open Access Journals (Sweden)

    Kristoffer eRomero

    2014-08-01

    Full Text Available Background: Numerous studies have shown decreased perfusion in the prefrontal cortex following mild traumatic brain injury (mTBI. However, similar hypoperfusion can also be observed in depression. Given the high prevalence of depressive symptoms following mTBI, it is unclear to what extent depression influences hypoperfusion in TBI.Methods: Mild TBI patients without depressive symptoms (mTBI-noD, n = 39, TBI patients with depressive symptoms (mTBI-D, n = 13, and 15 patients with major depressive disorder, but no TBI (MDD were given 99-m T-ECD SPECT scans within 2 weeks of injury. All subjects completed tests of information processing speed, complex attention, and executive functioning, and a self-report questionnaire measuring symptoms of psychological distress. Between group comparisons of quantified SPECT perfusion were undertaken, using univariate and multivariate (partial least squares analyses.Results: mTBI-D and mTBI-noD groups did not differ in terms of cerebral perfusion. However, patients with MDD showed hypoperfusion in several frontal (orbitofrontal, middle frontal, and superior frontal cortex, superior temporal, and posterior cingulate regions. The mTBI-D group showed poorer performance on a measure of complex attention and working memory, compared to both the mTBI-noD and MDD groups.Conclusions: These results suggest that depressive symptoms do not affect SPECT perfusion in the sub-acute phase following a mild TBI. Conversely, MDD is associated with hypoperfusion primarily in frontal regions.

  5. Contribution to the development of an absolute quantification method in Single Photon Emission Tomography of the brain

    International Nuclear Information System (INIS)

    Recent technical advances in SPECT have focused on the use of transmission imaging and on the development of new iterative algorithms for attenuation correction. These new tools can be coupled to approaches which compensate for scattering and spatial resolution, in order to quantify the radioactive concentration values in vivo. The main objective of this work was to investigate a quantification method of radioactivity uptake in small cerebral structures using SPECT. This method was based on the correction of attenuation using transmission data. Compton events were estimated and subtracted by positioning a lower energy window. Spatial resolution effects have been corrected using Fourier deconvolution. The radiation dose received by patients during transmission scans was evaluated using anthropomorphic phantoms and suitable dosimeters. A preliminary evaluation of the quantification method was carried out using an anthropomorphic head phantom. In a second phase, in vivo acquisitions were performed in baboon. The values of the percent injected doses per millilitre of tissue in baboon striata were compared under similar experimental conditions using SPECT and PET radiotracers specific for the D2 dopamine receptors. Experiments carried with anthropomorphic phantoms have indicated that the clinical use of transmission scans in SPECT is not limited by radiation doses. Measurements have demonstrated that attenuation dramatically affects quantification in brain SPECT. This effect can be corrected using a map of linear attenuation coefficients obtained through transmission scans and an iterative reconstruction algorithm. After correcting for attenuation, scatter and spatial resolution effects, the accuracy of activity concentration values measurement in the 'striata' of phantom is greatly improved. Results obtained in vivo show that the percent injected doses per millilitre of tissue can be measured with errors similar to those found in PET. This work demonstrates

  6. Single-photon emission tomography imaging of serotonin transporters in the non-human primate brain with the selective radioligand [{sup 123}I]IDAM

    Energy Technology Data Exchange (ETDEWEB)

    Acton, P.D.; Kung Mei-Ping; Mu Mu; Ploessl, K.; Hou, C.; Siciliano, M.; Oya Shunichi [Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States); Kung, H.F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States)]|[Department of Pharmacology, University of Pennsylvania, Philadelphia (United States)

    1999-08-01

    A new radioligand, 5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol ([{sup 123}I]IDAM), has been developed for selective single-photon emission tomography (SPET) imaging of SERT. In vitro binding studies suggest a high selectivity of IDAM for SERT (K{sub i}=0.097 nM), with considerably lower affinities for norepinephrine and dopamine transporters (NET K{sub i}= 234 nM and DAT K{sub i}>10 {mu}M, respectively). In this study the biodistribution of SERT in the baboon brain was investigated in vivo using [{sup 123}I]IDAM and SPET imaging. Dynamic sequences of SPET scans were performed on three female baboons (Papio anubis) after injection of 555 MBq of [{sup 123}I]IDAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 90-120 min after injection of [{sup 123}I]IDAM. Similar studies were performed using a NET inhibitor, nisoxetine, and a DAT blocker, methylphenidate. After 60-120 min, the regional distribution of tracer within the brain reflected the characteristic distribution of SERT, with the highest uptake in the midbrain area (hypothalamus, raphe nucleus, substantia nigra), and the lowest uptake in the cerebellum (an area presumed free of SERT). Peak specific binding in the midbrain occurred at 120 min, with a ratio to the cerebellum of 1.80{+-}0.13. At 30 min, 85% of the radioactivity in the blood was metabolite. Following injection of a competing SERT ligand, (+)McN5652, the tracer exhibited rapid washout from areas with high concentrations of SERT (dissociation rate constant in the midbrain, averaged over three baboons, k{sub off}=0.025{+-}0.002 min{sup -1}), while the cerebellar activity distribution was undisturbed (washout rate 0.0059{+-} 0.0003 min{sup -1}). Calculation of tracer washout rate pixel-by-pixel enabled the generation of parametric images of the dissociation rate constant. Similar studies using nisoxetine and methylphenidate had no effect on the distribution of [{sup 123}I]IDAM in the brain

  7. Single-photon emission tomography imaging of serotonin transporters in the non-human primate brain with the selective radioligand [[sup 123]I]IDAM

    Energy Technology Data Exchange (ETDEWEB)

    Acton, P.D.; Kung Mei-Ping; Mu Mu; Ploessl, K.; Hou, C.; Siciliano, M.; Oya Shunichi (Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States)); Kung, H.F. (Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States) Department of Pharmacology, University of Pennsylvania, Philadelphia (United States))

    1999-08-01

    A new radioligand, 5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol ([[sup 123]I]IDAM), has been developed for selective single-photon emission tomography (SPET) imaging of SERT. In vitro binding studies suggest a high selectivity of IDAM for SERT (K[sub i]=0.097 nM), with considerably lower affinities for norepinephrine and dopamine transporters (NET K[sub i]= 234 nM and DAT K[sub i]>10 [mu]M, respectively). In this study the biodistribution of SERT in the baboon brain was investigated in vivo using [[sup 123]I]IDAM and SPET imaging. Dynamic sequences of SPET scans were performed on three female baboons (Papio anubis) after injection of 555 MBq of [[sup 123]I]IDAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 90-120 min after injection of [[sup 123]I]IDAM. Similar studies were performed using a NET inhibitor, nisoxetine, and a DAT blocker, methylphenidate. After 60-120 min, the regional distribution of tracer within the brain reflected the characteristic distribution of SERT, with the highest uptake in the midbrain area (hypothalamus, raphe nucleus, substantia nigra), and the lowest uptake in the cerebellum (an area presumed free of SERT). Peak specific binding in the midbrain occurred at 120 min, with a ratio to the cerebellum of 1.80[+-]0.13. At 30 min, 85% of the radioactivity in the blood was metabolite. Following injection of a competing SERT ligand, (+)McN5652, the tracer exhibited rapid washout from areas with high concentrations of SERT (dissociation rate constant in the midbrain, averaged over three baboons, k[sub off]=0.025[+-]0.002 min[sup -1]), while the cerebellar activity distribution was undisturbed (washout rate 0.0059[+-] 0.0003 min[sup -1]). Calculation of tracer washout rate pixel-by-pixel enabled the generation of parametric images of the dissociation rate constant. Similar studies using nisoxetine and methylphenidate had no effect on the distribution of [[sup 123]I]IDAM in the brain

  8. Evaluation of brain perfusion with technetium-99m bicisate single-photon emission tomography in patients with depressive disorder before and after drug treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kocmur, M. [Department of Psychiatry, University Medical Centre, Ljubljana (Slovenia); Milcinski, M.; Budihna, N.V. [Department of Nuclear Medicine, University Medical Centre, Ljubljana (Slovenia)

    1998-10-01

    Depression is one of the most common psychiatric illnesses. Its influence on brain perfusion has been demonstrated, but conflicting data exist on follow-up after drug treatment. The aim of our study was to evaluate the effects of antidepressant drugs on regional cerebral blood flow (rCBF) in patients with depression after 3 weeks and 6 months of drug therapy. Clinical criteria for depression without psychosis were met according to psychiatric evaluation. Severity of depression was evaluated with the Hamilton Depression Rating Scale (HAMD) before every scintigraphic study. rCBF was assessed using technetium-99m bicisate (Neurolite) brain single-photon emission tomography in nine patients with severe depression before the beginning of antidepressant drug therapy and 3 weeks and six months after initiation of therapy. Only patients with no change in antidepressant medication during the study were included. No antipsychotic drugs were used. Cerebellum was used as the reference region. rCBF was evaluated for eight regions in each study in three consecutive transversal slices. Follow-up studies were compared with the baseline study. The mean HAMD score was 25.5 points initially, 16 at the second examination and 8.8 after 6 months. Global CBF was decreased compared with the reference region in drug-free patients. Perfusion of left frontal and temporal regions was significantly lower (P<0.005) in comparison with the contralateral side. After therapy, a moderate decrease in perfusion was seen in the right frontal region (P<0.05). Perfusion decreased further after 6 months in the right frontal (P<0.005) and temporal regions (P<0.01). The highly significant asymmetry in perfusion between the left and right frontal and temporal lobes almost disappeared during treatment. Our findings implicate dysfunction of the frontal and temporal cortex in clinically depressed patients before specific drug treatment. Clinical improvement and decreases in HAMD score after 3 weeks and after 6

  9. Dopamine transporter distribution in patients with Parkinson disease of different stages detected using single-photon emission computed tomography brain imaging

    Institute of Scientific and Technical Information of China (English)

    Jiwu Zhang; Lijuan Zhu; Jianqiang Du; Bo Liu

    2007-01-01

    . Following injection, image was collected using scanner for single photon emission computed tomography (ADAC Company, USA). Matrix was 64 × 64, each detecting head revolved 180 ° ,1 frame/60 s. Sixty-four frames were collected with double detecting heads, 50 K/frame. Faultages with clearest image of corpora striatum were selected. Regions of interest (ROI) of caudate nucleus, anterior and posterior putamen and thalamic region in bilateral corpora striata were radioactively counted, and mean value of radioactive counting of ROI was used as the mean value of pixel in each region of bilateral corpora striata.MAIN OUTCOME MEASURES: Comparison of radioactive uptake in each region of brain between healthy persons and patients with PD.RESULTS: Thirty patients with PD and six healthy persons who received body examination participated in the final result. Comparison of radioactive uptake in each region between healthy persons and patients with PD: ①In the healthy persons, high-density radioactive uptake was found in bilateral corpora striata;Structures of caudate nucleus, anterior and posterior putamen, and thalamus were clear with eudipleural radioactive distribution, and the background of peripheral brain tissue was very low. ②Radioactive intakes in opposite anterior and posterior putamen of patients with mild PD were significantly inferior to those in homolateral ones(70.45 ±3.35, 87.64±2.65, t =15.82, P < 0.05). Structures of bilateral caudate nucleus and Corresponding author: Jiwu Zhang,Department of Imageology, Second Hospital Affiliated to Guangzhou University of Chinese Medicine, Guangzhou 510120, Guangdong Province, China E-mail:zh-j-u@sohu.comthalamus were clear with eudipleural radioactive distribution (P > 0.05). ③ Radioactive intakes in anterior and posterior putamen and thalamus of patients with moderate PD were significantly reduced as compared with healthy persons. There were significant differences in mean radioactive counting of ROI between patients

  10. Dopamine transporter distribution in patients with Parkinson disease of different stages detected using single-photon emission computed tomography brain imaging

    Institute of Scientific and Technical Information of China (English)

    Jiwu Zhang; Lijuan Zhu; Jianqiang Du; Bo Liu

    2007-01-01

    . Following injection, image was collected using scanner for single photon emission computed tomography (ADAC Company, USA). Matrix was 64 × 64, each detecting head revolved 180 ° ,1 frame/60 s. Sixty-four frames were collected with double detecting heads, 50 K/frame. Faultages with clearest image of corpora striatum were selected. Regions of interest (ROI) of caudate nucleus, anterior and posterior putamen and thalamic region in bilateral corpora striata were radioactively counted, and mean value of radioactive counting of ROI was used as the mean value of pixel in each region of bilateral corpora striata.MAIN OUTCOME MEASURES: Comparison of radioactive uptake in each region of brain between healthy persons and patients with PD.RESULTS: Thirty patients with PD and six healthy persons who received body examination participated in the final result. Comparison of radioactive uptake in each region between healthy persons and patients with PD: ①In the healthy persons, high-density radioactive uptake was found in bilateral corpora striata;Structures of caudate nucleus, anterior and posterior putamen, and thalamus were clear with eudipleural radioactive distribution, and the background of peripheral brain tissue was very low. ②Radioactive intakes in opposite anterior and posterior putamen of patients with mild PD were significantly inferior to those in homolateral ones(70.45 ±3.35, 87.64±2.65, t =15.82, P < 0.05). Structures of bilateral caudate nucleus and Corresponding author: Jiwu Zhang,Department of Imageology, Second Hospital Affiliated to Guangzhou University of Chinese Medicine, Guangzhou 510120, Guangdong Province, China E-mail:zh-j-u@sohu.comthalamus were clear with eudipleural radioactive distribution (P > 0.05). ③ Radioactive intakes in anterior and posterior putamen and thalamus of patients with moderate PD were significantly reduced as compared with healthy persons. There were significant differences in mean radioactive counting of ROI between patients

  11. Electrically pumped single-photon emission up to 80 K—Towards a commercial single-photon emitting device

    Science.gov (United States)

    Reischle, M.; Beirne, G. J.; Schulz, W.-M.; Eichfelder, M.; Roßbach, R.; Jetter, M.; Michler, P.

    2010-01-01

    We report electically pumped single-photon emission in the visible spectral range up to 80 K using InP quantum dots embedded in AlGaInP barriers. In order to confirm that the emission is from a single quantum dot we performed second-order autocorrelation measurements and observed strong antibunching at zero time delay. Deviations from a perfect single-photon emitter could be explained by detector limitations and background signal.

  12. Monitoring CBF in clinical routine by dynamic single photon emission tomography (SPECT) of inhaled xenon-133

    DEFF Research Database (Denmark)

    Sugiyama, H; Christensen, J; Skyhøj Olsen, T;

    1986-01-01

    A very simple and low-cost brain dedicated, rapidly rotating Single Photon Emission Tomograph SPECT is described. Its use in following patients with ischemic stroke is illustrated by two middle cerebral artery occlusion cases, one with persistent occlusion and low CBF in MCA territory, and one with...

  13. Single photon emission computed tomography: A clinical experience

    International Nuclear Information System (INIS)

    In the past decade, single photon emission computed tomography (SPECT) has evolved from an experimental technique used only in academic settings to a routine clinical examination performed in many community hospitals. Responding to reports of increased diagnostic efficacy, many nuclear medicine physicians have chosen to make SPECT imaging a routine technique for bone, liver, spleen, heart, and brain imaging. However, the enthusiasm for SPECT is not universal. Most nuclear medicine physicians continue to rely primarily on planar imaging, with little or no routine use of SPECT. This milieu has left many physicians asking themselves the following practical questions: Can SPECT be done easily in my hospital? Will not doing SPECT reduce the competitiveness of my nuclear medicine laboratory? The authors' experience at an institution heavily committed to SPECT for over 5 years may be helpful in answering these types of questions. The first rotating gamma camera at the Milwaukee Regional Medical Center was installed in late 1981. At present the authors have eight gamma cameras, of which four routinely perform SPECT examinations. Between 1981 and 1986, over 4,000 SPECT examinations have been performed

  14. Proceedings of clinical SPECT [single photon emission computed tomography] symposium

    International Nuclear Information System (INIS)

    It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluation of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With respect to the technical aspect of the program we have selected the key areas which demand awareness and attention in order to make SPECT operational in clinical practice. These include selection of equipment, details of uniformity correction, utilization of phantoms for equipment acceptance and quality assurance, the major aspect of algorithms, an understanding of filtered back projection and appropriate choice of filters and an awareness of the most commonly generated artifacts and how to recognize them. With respect to the acquisition and interpretation of organ images, the faculty will present information on the major aspects of hepatic, brain, cardiac, skeletal, and immunologic imaging techniques. Individual papers are processed separately for the data base

  15. Proceedings of clinical SPECT (single photon emission computed tomography) symposium

    Energy Technology Data Exchange (ETDEWEB)

    1986-09-01

    It has been five years since the last in-depth American College of Nuclear Physicians/Society of Nuclear Medicine Symposium on the subject of single photon emission computed tomography (SPECT) was held. Because this subject was nominated as the single most desired topic we have selected SPECT imaging as the basis for this year's program. The objectives of this symposium are to survey the progress of SPECT clinical applications that have taken place over the last five years and to provide practical and timely guidelines to users of SPECT so that this exciting imaging modality can be fully integrated into the evaluation of pathologic processes. The first half was devoted to a consideration of technical factors important in SPECT acquisition and the second half was devoted to those organ systems about which sufficient clinical SPECT imaging data are available. With respect to the technical aspect of the program we have selected the key areas which demand awareness and attention in order to make SPECT operational in clinical practice. These include selection of equipment, details of uniformity correction, utilization of phantoms for equipment acceptance and quality assurance, the major aspect of algorithms, an understanding of filtered back projection and appropriate choice of filters and an awareness of the most commonly generated artifacts and how to recognize them. With respect to the acquisition and interpretation of organ images, the faculty will present information on the major aspects of hepatic, brain, cardiac, skeletal, and immunologic imaging techniques. Individual papers are processed separately for the data base. (TEM)

  16. Brain single-photon emission tomography with 99mTc-HMPAO in neuropsychiatric systemic lupus erythematosus: relations with EEG and MRI findings and clinical manifestations

    International Nuclear Information System (INIS)

    In the reported study the role of single-photon emission tomography (SPET) with technetium-99m hexamethylpropylene amine oxime (HMPAO) in the evaluation of CNS involvement in SLE was assessed and the relations between SPET perfusion defects, EEG examination, magnetic resonance imaging (MRI) findings and clinical presentation were examined. Twenty SLE patients with different NP manifestations were studied. Multiple areas of hypoperfusion, especially in the territory of the middle cerebral artery, were demonstrated by SPET analysis in all 20 patients. The number of hypoperfused areas and the degree of hypoperfusion, expressed by an asymmetry index (AI), were more marked in patients with multiple NP manifestations. MRI and EEG evaluations were positive for 14 of 18 and for 12 of 20 patients, respectively. In the patients with positive SPET and MRI, 87 MRI focal lesions and 63 hypoperfused areas were found, and for 51 of these 63 at least one MRI lesion was found in the same anatomical region. SPET examination of patients with a normal EEG showed fewer hypoperfused areas and a lower degree of asymmetry compared to patients with an abnormal EEG. SPET of patients with focal EEG abnormalities showed more hypoperfused areas (difference not statistically significant) and a higher AI than did SPET of the patients with diffuse EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities had co-localized hypoperfused areas and in two of these seven no detectable MRI lesions were found. The analysis of SPET and NP manifestations showed that 12 of 20 patients had at least one positive correlation, always involving the areas with the highest AI. In total, 51/88 (58%) hypoperfused areas correlated with the MRI findings and 31/88 (35%) with NP manifestations; for seven of the latter no concurrent MRI lesions were detected in the same anatomical region. (orig.)

  17. Single Photon Subradiance: Quantum control of spontaneous emission and ultrafast readout

    OpenAIRE

    Scully, Marlan O.

    2015-01-01

    Recent work has shown that collective single photon emission from an ensemble of resonate two-level atoms, i.e. single photon superradiance, is a rich field of study. The present paper addresses the flip side of superradiance, i.e. subradiance. Single photon subradiant states are potentially stable against collective spontaneous emission and can have ultrafast readout. In particular it is shown how many atom collective effects provide a new way to control spontaneous emission by preparing and...

  18. Reconstruction Algorithms for Positron Emission Tomography and Single Photon Emission Computed Tomography and their Numerical Implementation

    CERN Document Server

    Fokas, A S; Marinakis, V

    2004-01-01

    The modern imaging techniques of Positron Emission Tomography and of Single Photon Emission Computed Tomography are not only two of the most important tools for studying the functional characteristics of the brain, but they now also play a vital role in several areas of clinical medicine, including neurology, oncology and cardiology. The basic mathematical problems associated with these techniques are the construction of the inverse of the Radon transform and of the inverse of the so called attenuated Radon transform respectively. We first show that, by employing mathematical techniques developed in the theory of nonlinear integrable equations, it is possible to obtain analytic formulas for these two inverse transforms. We then present algorithms for the numerical implementation of these analytic formulas, based on approximating the given data in terms of cubic splines. Several numerical tests are presented which suggest that our algorithms are capable of producing accurate reconstruction for realistic phanto...

  19. Single Photon Emission Tomography Imaging in Parkinsonian Disorders: A Review

    Directory of Open Access Journals (Sweden)

    Paul D. Acton

    2000-01-01

    Full Text Available Parkinsonian symptoms are associated with a number of neurodegenerative disorders, such as Parkinson’s disease, multiple system atrophy and progressive supranuclear palsy. Pathological evidence has shown clearly that these disorders are associated with a loss of neurons, particularly in the nigrostriatal dopaminergic pathway. Positron emission tomography (PET and single photon emission tomography (SPECT now are able to visualise and quantify changes in cerebral blood flow, glucose metabolism, and dopaminergic function produced by parkinsonian disorders. Both PET and SPECT have become important tools in the differential diagnosis of these diseases, and may have sufficient sensitivity to detect neuronal changes before the onset of clinical symptoms. Imaging is now being utilised to elucidate the genetic contribution to Parkinson’s disease, and in longitudinal studies to assess the efficacy and mode of action of neuroprotective drug and surgical treatments. This review summarises recent applications of SPECT imaging in the study of parkinsonian disorders, with particular reference to the increasing role it is playing in the understanding, diagnosis and management of these diseases.

  20. Single photon emission computed tomography-guided Cerenkov luminescence tomography

    Science.gov (United States)

    Hu, Zhenhua; Chen, Xueli; Liang, Jimin; Qu, Xiaochao; Chen, Duofang; Yang, Weidong; Wang, Jing; Cao, Feng; Tian, Jie

    2012-07-01

    Cerenkov luminescence tomography (CLT) has become a valuable tool for preclinical imaging because of its ability of reconstructing the three-dimensional distribution and activity of the radiopharmaceuticals. However, it is still far from a mature technology and suffers from relatively low spatial resolution due to the ill-posed inverse problem for the tomographic reconstruction. In this paper, we presented a single photon emission computed tomography (SPECT)-guided reconstruction method for CLT, in which a priori information of the permissible source region (PSR) from SPECT imaging results was incorporated to effectively reduce the ill-posedness of the inverse reconstruction problem. The performance of the method was first validated with the experimental reconstruction of an adult athymic nude mouse implanted with a Na131I radioactive source and an adult athymic nude mouse received an intravenous tail injection of Na131I. A tissue-mimic phantom based experiment was then conducted to illustrate the ability of the proposed method in resolving double sources. Compared with the traditional PSR strategy in which the PSR was determined by the surface flux distribution, the proposed method obtained much more accurate and encouraging localization and resolution results. Preliminary results showed that the proposed SPECT-guided reconstruction method was insensitive to the regularization methods and ignored the heterogeneity of tissues which can avoid the segmentation procedure of the organs.

  1. Single photon emission computed tomography in periatric frontal epilepsy

    International Nuclear Information System (INIS)

    Neuroradiological examinations were made in 9 pediatric patients with frontal epilepsy by using single photon emission computed tomography (SPECT), cat scanning (CT) and magnetic resonance imaging (MRI). Two patients (22%) had abnormal findings on both CT and MRI; and 6 patients (67%) had them on SPECT, two of whom had findings corresponding to focal sites on EEG. Among the 6 patients, 5 were suspected of having decreased regional cerebral blood flow (rCBF), corresponding to 84%-94% of the contralateral blood flow. Two patients were evaluable before and after seizures; one had increased rCBF at the time of frequent seizures and returned to normal after seizures; and the other had no abnormality in the early stage of epilepsy, but had decreased rCBF after seizures. SPECT appears to provide a simple, useful tool in evaluating cerebral hemodynamics in infantile epilepsy, although serial hemodynamic changes with developmental process of central nerves and the time of examination must be considered according to individual patients. (N.K.)

  2. Single-Photon Emission Computed Tomography (SPECT) in childhood epilepsy

    International Nuclear Information System (INIS)

    The success of epilepsy surgery is determined strongly by the precise location of the epileptogenic focus. The information from clinical electrophysiological data needs to be strengthened by functional neuroimaging techniques. Single photon emission computed tomography (SPECT) available locally has proved useful as a localising investigation. It evaluates the regional cerebral blood flow and the comparison between ictal and interictal blood flow on SPECT has proved to be a sensitive nuclear marker for the site of seizure onset. Many studies justify the utility of SPECT in localising lesions to possess greater precision than interictal scalp EEG or anatomic neuroimaging. SPECT is of definitive value in temporal lobe epilepsy. Its role in extratemporal lobe epilepsy is less clearly defined. It is useful in various other generalized and partial seizure disorders including epileptic syndromes and helps in differentiating pseudoseizures from true seizures. The need for newer radiopharmaceutical agents with specific neurochemical properties and longer shelf life are under investigation. Subtraction ictal SPECT co-registered to MRI is a promising new modality. (author)

  3. Single photon image from position emission tomography with insertable collimator for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo Young; Yoo, Do Kun; Suh, Tae Suk [Dept. of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of); Hong, Key Jo [Molecular Imaging Program at Stanford (MIPS), Dept. of Radiology, Stanford University, Stanford (United States)

    2014-04-15

    The aim of our proposed system is to confirm the feasibility of extraction of two types of images from one positron emission tomography (PET) module with an insertable collimator for brain tumor treatment during the boron neutron capture therapy (BNCT). The BNCT theory and conceptual diagram of our proposed system are shown fig.1. Data from the PET module, neutron source, and collimator was entered in the Monte Carlon-particle extende source code. We attempted to acquire the PET and SPECT images simultaneously using only PET without an additional isotope. Single photon images were acquired using an insertable collimator on a PET detector.

  4. Adverse effects of intravenous acetazolamide administration for evaluation of cerebrovascular reactivity using brain perfusion single-photon emission computed tomography in patients with major cerebral artery steno-occlusive diseases

    International Nuclear Information System (INIS)

    Adverse effects of intravenous acetazolamide administration for evaluation of cerebrovascular reactivity using brain perfusion single-photon emission computed tomography (SPECT) were prospectively investigated in 100 patients with major cerebral artery, atherosclerotic, and steno-occlusive diseases. All patients underwent two SPECT studies (with and without acetazolamide challenge) at an interval of 2 or 3 days, received a questionnaire immediately after each SPECT study, and returned the answered questionnaire within 7 days after the study. None of the 100 patients studied experienced any symptoms during the SPECT study without acetazolamide challenge. Sixty-three patients (63%) developed symptoms during the SPECT study with acetazolamide challenge, such as headache, nausea, dizziness, tinnitus, numbness of the extremities, motor weakness of the extremities, and general malaise 1-3 hours (mean 1.6 hours) after administration of acetazolamide, and these symptoms lasted for 0.5-72 hours (mean 7.9 hours). Multivariate statistical analysis revealed that younger age (95% confidence interval [CI] 0.896-0.980, p=0.0047) and female sex (95% CI 1.178-16.129, p=0.0274) were significantly associated with development of symptoms with acetazolamide challenge. The incidences of the development of symptoms with acetazolamide challenge were 91% (21/23) and 41% (12/29) in subgroups of women <70 years and men ≥70 years, respectively. Patients should be informed of such adverse effects of intravenous acetazolamide administration prior to the acetazolamide challenge test for evaluation of cerebrovascular reactivity. (author)

  5. Study of 99m Tc-TRODAT-1 Imaging on Human Brain with Children Autism by Single Photon Emission Computed Tomography

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective: Evaluate the application values of 99mTc-2 β [ N, N'-bis( 2-mercaptoethy1 ) ethylenediamino ] methyl, 3 β -(4-chlorophenyl) tropane ( TRODAT-1 ) dopamine transporter (DAT) SPECT imaging in children autism, and offer the academic foundation to etiology, mechanism and clinical therapy of autism. Methods:Ten autistic children and ten healthy controls were examined with 99mTc-TRODAT-1 DAT SPECT imaging.Striatal specific uptake of 99mTc-TRODAT-1 was calculated with region of interest analysis according to the ratios between striatum and cerebellum [ (STR-BKG)/BKG]. Results:There was no difference in semiquantitative dopamine transporter between bilateral striatum in autistic children ( P = 0. 562) and in normal controls ( P = 0. 573 ); dopamine transporter in brain of patients with autism increased more significantly than that in normal controls ( P = 0. 017 ). Conclusion: Dopaminergic nervous system is dysfunction in human brain with children autism, and DAT 99mTc-TRODAT-1 SPECT imaging on human brain will help the imaging diagnosis of children autism.

  6. Single photon emission computed tomography using 99Tcm-HMPAO in Alzheimer's disease

    International Nuclear Information System (INIS)

    Brain single photon emission computed tomography (SPET) using 99mTcm-hexamethylpropyleneamine oxime (HMPAO) was performed in 37 patients satisfying standard clinical criteria of Alzheimer's disease (AD), correlating results with patient's age of onset, duration of illness, severity of dementia, neuropsychological impairment, computed tomography (CT) and EEG findings. All had abnormal SPET: 23 were bilaterally symmetric, 10 bilaterally asymmetric and four showed unilateral low regional cerebral perfusion. Low perfusion in bilateral parietal regions was the most consistent finding and was present alone or with other abnormal regions in 31 patients (84%). The only significant clinical correlation was found between asymmetric SPECT changes and onset of disease before the age of 65 years. 50% of patients with presenile onset, but only 19% with senile onset had asymmetric low regional cerebral perfusion. Fifteen of the 36 patients had normal brain CT scans, and 9 of 31 patients receiving EEG examination had normal results. (author)

  7. Hot water epilepsy: Phenotype and single photon emission computed tomography observations

    Directory of Open Access Journals (Sweden)

    Mehul Patel

    2014-01-01

    Full Text Available We studied the anatomical correlates of reflex hot water epilepsy (HWE using multimodality investigations viz. magnetic resonance imaging (MRI, electroencephalography (EEG, and single photon emission computed tomography (SPECT. Five men (mean age: 27.0 ΁ 5.8 years with HWE were subjected to MRI of brain, video-EEG studies, and SPECT scan. These were correlated with phenotypic presentations. Seizures could be precipitated in three patients with pouring of hot water over the head and semiology of seizures was suggestive of temporal lobe epilepsy. Ictal SPECT showed hyperperfusion in: left medial temporal - one, left lateral temporal - one, and right parietal - one. Interictal SPECT was normal in all five patients and did not help in localization. MRI and interictal EEG was normal in all the patients. The clinical and SPECT studies suggested temporal lobe as the seizure onset zone in some of the patients with HWE.

  8. Single photon emission CT perfusion imaging of cerebral blood flow of early syphilis patients

    Institute of Scientific and Technical Information of China (English)

    施辛; 吴锦昌; 刘增礼; 唐军; 苏玉华

    2003-01-01

    Objective To injvestigate the cerebral blood flow of patients with early syphilis. Methods 99Tcm-ECD as brain perfusion imaging agent was used in single photon emission computed tomography (SPECT) for 32 patients with early syphilis and 15 controls. Visual analyses were made on every BSPECT image. Results The 32 patients with early syphilis had general, patchy hypoperfusion of cerebral blood flow. Fourteen of the 32 patients had 48 episodes of marked patchy hypoperfusion of rCBF. The responsible areas of hypoperfusion in a patchy distribution involved the left frontal lobe (6 episodes), right frontal lobe (3), left parietal lobe (7), right parietal lobe (6), left temporal lobe (11), right temporal lobe (5), left occipital lobe (3), left basal ganglia (3), cerebellum (1), and nerve nuceus (1). No abnormality was found in the control group.Conclusions Cerebral blood flow abnormalities exist in patients with early syphilis. General patchy hypoperfusion on SPECT imaging is common.

  9. Cerebral functional imaging of Waiguan (SJ 5) acupoint specificity using single-photon emission computed tomography

    Institute of Scientific and Technical Information of China (English)

    Yong Huang; Yangjia Lu; Ganlong Li; Xinsheng Lai; Hong Zhang; Chunzhi Tang; Junjun Yang

    2011-01-01

    The action of needling in acupoint therapy has to first be regulated and integrated by the brain, and then it affects the target organ and manifests its therapeutic effects, which is dependent on the specificity of the acupoints. The authors put forward the hypothesis of the "acupoint-related brain". Single-photon emission computed tomography was used to explore the activation of brain regions following true needling in true acupoint Waiguan (SJ 5), sham needling in true acupoint Waiguan, true needling in a sham point, and sham needling in a sham point. The relative specificity of Waiguan in normal persons was analyzed by observing changes in regional cerebral blood flow. Compared with the sham needling in true acupoint group and sham needling in the sham point group, acupuncture at Waiguan can activate brain regions controlling movement. Compared with true needling in the sham point group, acupuncture at Waiguan can also activate brain regions controlling movement. The results suggest that the specificity of needling at an acupoint is related to certain activated cerebral functional regions, which are associated with the clinical application of the acupoint.

  10. Single-photon emission computed tomography and positron-emission tomography assays for tissue oxygenation.

    Science.gov (United States)

    Chapman, J D; Schneider, R F; Urbain, J L; Hanks, G E

    2001-01-01

    Radiotherapy prescription can now be customized to target the major mechanism(s) of resistance of individual tumors. In that regard, functional imaging techniques should be exploited to identify the dominant mechanism(s). Tumor biology research has identified several mechanisms of tumor resistance that may be unique to radiation treatments. These fall into 3 broad areas associated with (1) tumor hypoxic fraction, (2) tumor growth rate, (3) and the intrinsic radiosensitivity of tumor clonogens. Imaging research has markers in various stages of development for quantifying relevant information about each of these mechanisms, and those that measure tumor oxygenation and predict for radioresistance are the most advanced. Positron-emission tomography (PET) measurement of oxygen 15 has yielded important information, particularly about brain tissue perfusion, metabolism, and function. Indirect markers of tumor hypoxia have exploited the covalent binding of bioreductive intermediates of azomycin-containing compounds whose uptakes are inversely proportional to intracellular oxygen concentrations. Pilot clinical studies with single-photon emission computed tomography (SPECT) and PET detection of radiolabeled markers to tumor hypoxia have been reported. Recently, other studies have attempted to exploit the reduction properties of both technetium and copper chelates for the selective deposition of radioactive metals in hypoxic tissues. A growing number of potentially useful isotopes are now available for labeling several novel chemicals that could have the appropriate specificity and sensitivity. Preclinical studies with "microSPECT" and "microPET" will be important to define the optimal radiodiagnostic(s) for measuring tissue oxygenation and for determining the time after their administration for optimal hypoxic signal acquisition. Radiolabeled markers of growth kinetics and intrinsic radiosensitivity of cells in solid tumors are also being developed. We conclude that

  11. Design of highly efficient metallo-dielectric patch antennas for single-photon emission.

    Science.gov (United States)

    Bigourdan, F; Marquier, F; Hugonin, J-P; Greffet, J-J

    2014-02-10

    Quantum emitters such as NV-centers or quantum dots can be used as single-photon sources. To improve their performance, they can be coupled to microcavities or nano-antennas. Plasmonic antennas offer an appealing solution as they can be used with broadband emitters. When properly designed, these antennas funnel light into useful modes, increasing the emission rate and the collection of single-photons. Yet, their inherent metallic losses are responsible for very low radiative efficiencies. Here, we introduce a new design of directional, metallo-dielectric, optical antennas with a Purcell factor of 150, a total efficiency of 74% and a collection efficiency of emitted photons of 99%.

  12. Controlling light emission from single-photon sources using photonic nanowires

    DEFF Research Database (Denmark)

    Gregersen, Niels; Chen, Yuntian; Mørk, Jesper;

    2012-01-01

    are used to tailor the far-field emission pattern. This non-resonant approach relaxes the demands to fabrication perfection, allowing for record-high measured efficiency of fabricated nanowire single-photon sources. We review recent progress in photonic nanowire technology and present next generation...

  13. Single-Photon Emission from a Single InAs Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    DOU Xiu-Ming; SUN Bao-Quan; HUANG She-Song; NI Hai-Qiao; NIU Zhi-Chuan

    2008-01-01

    Excitation power-dependent micro-photoluminescence spectra and photon-correlation measurement are used to study the optical properties and photon statistics of single InAs quantum dots.Exciton and biexciton emissions,whose photoluminescence intensities have linear and quadratic excitation power dependences,respectively,are identified.Under pulsed laser excitation,the zero time delay peak of second order correlation function corresponding to exciton emission is well suppressed,which is a clear evidence of single photon emission.

  14. Towards an optimal reference region in single-photon emission tomography difference images in epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Boussion, N.; Ryvlin, P.; Isnard, J.; Mauguiere, F. [Neurologie Fonctionnelle et Epilepsie, Hopital Neurologique, Lyon (France); Houzard, C. [Centre de Medecine Nucleaire, Hopital Neuro-Cardiologique, Lyon (France); Cinotti, L. [Neurologie Fonctionnelle et Epilepsie, Hopital Neurologique, Lyon (France); Centre de Medecine Nucleaire, Hopital Neuro-Cardiologique, Lyon (France); CERMEP, Hopital Neuro-Cardiologique, Lyon (France)

    2000-02-01

    There is marked variability in the cerebral blood flow (CBF) between the ictal and interictal state in epilepsy, and it would therefore be desirable to increase the reliability of ictal/interictal single-photon emission tomography (SPET) difference images. We aimed to improve the step of quantitative normalization of images by finding the best possible reference region. In 16 patients (11 with lateralization of the epileptogenic focus, five with bilateral foci) both ictal and inter-ictal SPET scans were performed after injection of technetium-99m labelled tracer. Then, each region among a selected set (brain+cerebellum, brain, cerebellum, hemispheres, and for patients with an expected lateralization, cortical lobe containing the focus and symmetrical contralateral lobe) was investigated by comparison of the regional ictal/inter-ictal variance in counts. Among patients with a suspected lateralized focus, the distribution of CBF in the contralateral cortical lobe appeared to vary less between ictal and inter-ictal states than in other investigated areas. As a consequence, this latter region constitutes the best choice as a reference region. For patients with bilateral foci, the cerebellum appears to be a good compromise even though it presents with significant CBF changes. (orig.)

  15. Ultrafast Room-Temperature Single Photon Emission from Quantum Dots Coupled to Plasmonic Nanocavities.

    Science.gov (United States)

    Hoang, Thang B; Akselrod, Gleb M; Mikkelsen, Maiken H

    2016-01-13

    Efficient and bright single photon sources at room temperature are critical components for quantum information systems such as quantum key distribution, quantum state teleportation, and quantum computation. However, the intrinsic radiative lifetime of quantum emitters is typically ∼10 ns, which severely limits the maximum single photon emission rate and thus entanglement rates. Here, we demonstrate the regime of ultrafast spontaneous emission (∼10 ps) from a single quantum emitter coupled to a plasmonic nanocavity at room temperature. The nanocavity integrated with a single colloidal semiconductor quantum dot produces a 540-fold decrease in the emission lifetime and a simultaneous 1900-fold increase in the total emission intensity. At the same time, the nanocavity acts as a highly efficient optical antenna directing the emission into a single lobe normal to the surface. This plasmonic platform is a versatile geometry into which a variety of other quantum emitters, such as crystal color centers, can be integrated for directional, room-temperature single photon emission rates exceeding 80 GHz. PMID:26606001

  16. Diamond based light-emitting diode for visible single-photon emission at room temperature

    Science.gov (United States)

    Lohrmann, A.; Pezzagna, S.; Dobrinets, I.; Spinicelli, P.; Jacques, V.; Roch, J.-F.; Meijer, J.; Zaitsev, A. M.

    2011-12-01

    Diamond-based p-i-n light-emitting diodes capable of single-photon emission in the visible spectral region at room temperature are discussed. The diodes were fabricated on a high quality single crystal diamond grown by chemical vapor deposition. Implantation of boron and phosphorus ions followed by annealing at a temperature of 1600 °C has been used for doping p-type and n-type areas, respectively. Electrical characterization of the devices demonstrates clear diode behavior. Spectra of electroluminescence generated in the i-area reveal sole emission from the neutral nitrogen-vacancy (NV) defects. Photon antibunching implies single-photon character of this emission when generated by individual NV defects.

  17. 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.

  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 tab

  19. Single photon emission computed tomography in Alzheimer's disease. Abnormal iofetamine I 123 uptake reflects dementia severity

    International Nuclear Information System (INIS)

    To determine whether abnormalities in regional cerebral functional activity estimated by iofetamine hydrochloride I 123 and single photon emission computed tomography can be detected in mild or moderate as well as severe cases of Alzheimer's disease (AD), we performed iofetamine I 123-single photon emission computed tomography in 37 patients with probable AD (nine patients with mild, 18 patients with moderate, and ten patients with severe dementia) and nine age-matched control subjects. Iofetamine I 123 uptake was measured in right and left frontal, temporal, parietal, and occipital cortices. Mean (right and left) iofetamine I 123 activity was lowest in the parietal region of patients with AD and was significantly reduced in the other three regions compared with control subjects. Only in the parietal region was lower relative iofetamine I 123 activity associated with an impaired level of patient function and with cognitive deficit

  20. Potential new approaches for the development of brain imaging agents for single-photon applications

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, F.F. Jr.; Srivastava, P.C.

    1984-01-01

    This paper describes new strategies for the brain-specific delivery of radionuclides that can be used to evaluate regional cerebral perfusion by single photon imaging techniques. A description of several examples of interesting new strategies that have recently been reported is presented. A new approach at this institution for the brain-specific delivery of radioiodinated iodophenylalkyl-substituted dihyronicotinamide systems is described which shows good brain uptake and retention in preliminary studies in rats. Following transport into the brain these agents appear to undergo facile intracerebral oxidation to the quaternized analogues which do not recross the intact blood-brain barrier and so are effectively trapped in the brain. 49 refs., 9 figs., 1 tab.

  1. Advances in Single-Photon Emission Computed Tomography Hardware and Software.

    Science.gov (United States)

    Piccinelli, Marina; Garcia, Ernest V

    2016-02-01

    Nuclear imaging techniques remain today's most reliable modality for the assessment and quantification of myocardial perfusion. In recent years, the field has experienced tremendous progress both in terms of dedicated cameras for cardiac applications and software techniques for image reconstruction. The most recent advances in single-photon emission computed tomography hardware and software are reviewed, focusing on how these improvements have resulted in an even more powerful diagnostic tool with reduced injected radiation dose and acquisition time.

  2. Combined single photon emission computerized tomography and conventional computerized tomography: Clinical value for the shoulder surgeons?

    OpenAIRE

    Hirschmann, Michael T.; Rahel Schmid; Ranju Dhawan; Jiri Skarvan; Helmut Rasch; Friederich, Niklaus F.; Roger Emery

    2011-01-01

    With the cases described, we strive to introduce single photon emission computerized tomography in combination with conventional computer tomography (SPECT/CT) to shoulder surgeons, illustrate the possible clinical value it may offer as new diagnostic radiologic modality, and discuss its limitations. SPECT/CT may facilitate the establishment of diagnosis, process of decision making, and further treatment for complex shoulder pathologies. Some of these advantages were highlighted in cases that...

  3. Degenerative dementia: nosological aspects and results of single photon emission computed tomography

    International Nuclear Information System (INIS)

    Ten years ago, the diagnosis discussion of a dementia case for the old patient was limited to two pathologies: the Alzheimer illness and the Pick illness. During these last years, the frame of these primary degenerative dementia has fallen into pieces. The different diseases and the results got with single photon emission computed tomography are discussed. for example: fronto-temporal dementia, primary progressive aphasia, progressive apraxia, visio-spatial dysfunction, dementia at Lewy's bodies, or cortico-basal degeneration. (N.C.)

  4. Surface acoustic wave regulated single photon emission from a coupled quantum dot-nanocavity system

    CERN Document Server

    Weiß, Matthias; Reichert, Thorsten; Finley, Jonathan J; Wixforth, Achim; Kaniber, Michael; Krenner, Hubert J

    2016-01-01

    A coupled quantum dot--nanocavity system in the weak coupling regime of cavity quantumelectrodynamics is dynamically tuned in and out of resonance by the coherent elastic field of a $f_{\\rm SAW}\\simeq800\\,\\mathrm{MHz}$ surface acoustic wave. When the system is brought to resonance by the sound wave, light-matter interaction is strongly increased by the Purcell effect. This leads to a precisely timed single photon emission as confirmed by the second order photon correlation function $g^{(2)}$. All relevant frequencies of our experiment are faithfully identified in the Fourier transform of $g^{(2)}$, demonstrating high fidelity regulation of the stream of single photons emitted by the system. The implemented scheme can be directly extended to strongly coupled systems and acoustically drives non-adiabatic entangling quantum gates based on Landau-Zener transitions.

  5. Single photon emission tomography in neurological studies: Instrumentation and clinical applications

    International Nuclear Information System (INIS)

    One triple head and two single head gamma camera systems were used for single photon emission tomography (SPET) imaging of both patients and brain phantoms. Studies with an anatomical brain phantom were performed for evaluation of reconstruction and correction methods in brain perfusion SPET studies. The use of the triple head gamma camera system resulted in a significant increase in image contrast and resolution. This was mainly due to better imaging geometry and the use of a high resolution collimator. The conventional Chang attenuation correction was found suitable for the brain perfusion studies. In the brain perfusion studies region of interest (ROI) based semiquantitation methods were used. A ROI map based on anatomical areas was used in 70 elderly persons (age range 55-85 years) without neurological diseases and in patients suffering from encephalitis or having had a cardiac arrest. Semiquantitative reference values are presented. For the 14 patients with encephalitis the right-to-left side differences were calculated. Defect volume indexes were calculated for 64 patients with brain infarcts. For the 30 cardiac arrest patients the defect percentages and the anteroposterior ratios were used for semiquantitation. It is concluded that different semiquantitation methods are needed for the various patient groups. Age-related reference values will improve the interpretation of SPET data. For validation of the basal ganglia receptor studies measurements were performed using a cylindrical and an anatomical striatal phantom. In these measurements conventional and transmission imaging based non-uniform attenuation corrections were compared. A calibration curve was calculated for the determination of the specific receptor uptake ratio. In the phantom studies using the triple head camera the uptake ratio obtained from simultaneous transmission-emission protocol (STEP) acquisition and iterative reconstruction was closest to the true activity ratio. Conventional

  6. Single-Photon Emission Computerized Tomography (SPECT in Neuropsychiatry: A Review

    Directory of Open Access Journals (Sweden)

    B. K. Puri

    1992-01-01

    Full Text Available Cranial single-photon emission computerized tomography (SPECT or SPET can now give regional cerebral blood flow images with a resolution approaching that of positron emission tomography (PET. In this paper, the use of high resolution SPECT neuroimaging in neuropsychiatric disorders, including Alzheimer's disease, multi-infarct dementia, Pick's disease, progressive supranuclear palsy, Korsakoff's psychosis, Creutzfeld-Jakob disease, Parkinson's disease, Huntington's disease, schizophrenia, mood disorders, obsessive–compulsive disorder, HIV infection and AIDS is reviewed. Finally, further potential research and clinical uses, based on ligand studies, are outlined.

  7. Cerebral blood flow single-photon emission tomography with 123I-IMP in vascular dementia

    International Nuclear Information System (INIS)

    Cerebral blood flow differences between patients with vascular dementia, patients with multiple lacunar infarction without cognitive dysfunction, and age-matched controls were examined. Thirty four patients with vascular dementia (VD) were selected from consecutive referrals to the Memory Clinic at Narita Memorial Hospital. All the patients had routine assessment including history, physical and neurological examinations, neuropsychological assessment, blood tests, EEG, head MRI, and single photon emission computed tomography (SPECT). All of them fulfilled the NINDS-AIREN diagnostic criteria for vascular dementia. Thirty nine patients with multiple lacunar infarction without cognitive dysfunction and 110 age-matched controls were included in this study. Mean cerebral blood flow (mCBF) and regional cerebral blood flow (rCBF) were measured using N-isopropyl-P-123I-iodoamphetamine (123I-IMP) and SPECT imager. The mCBF in VD was 27.6±5.3 ml/100 g/min, while those in the control group and multiple lacunar infarction without cognitive dysfunction were 36.6±6.1 ml/100 g/min and 32.5±5.5 ml/100 g/min, respectively. The patients with VD demonstrated significantly reduced mCBF and rCBF in twenty regions including both cerebellar hemispheres as compared with those of the control group. Although there was no significant rCBF differences in bilateral inferior occipital regions and the right cerebellar hemisphere between patients with VD and multiple lacunar infarction without cognitive dysfunction, we could find significant lower rCBF in the remaining brain areas. In spite of the severity of VD, the diffuse decrease of cerebral blood flow was recognized in all patients with VD. (author)

  8. Dead time correction in positron emission tomograph. A method using single photon rate

    Energy Technology Data Exchange (ETDEWEB)

    Senda, Michio; Yonekura, Yoshiharu; Mukai, Takao; Fujita, Toru; Torizuka, Kanji

    1987-06-01

    The count rate linearity and dead time count losses were evaluated in Positologica III, a wholebody multislice positron emission tomograph, using several kinds of phantoms. A wide variation was observed in the relationship between count loss and true coincidence count rate depending on the source distribution, and the dead time correction using the count rate itself was unsuccessful. Since most count losses of this PET scanner occur when the single photon signals were encoded at the circuitry, we measured the single rate to correct for the count loss. This method enabled dead time correction independent of the distribution of source and attenuation material.

  9. Single photon emission computed tomography (SPECT of anxiety disorders before and after treatment with citalopram

    Directory of Open Access Journals (Sweden)

    Seedat Soraya

    2004-10-01

    Full Text Available Abstract Background Several studies have now examined the effects of selective serotonin reuptake inhibitor (SSRI treatment on brain function in a variety of anxiety disorders including obsessive-compulsive disorder (OCD, posttraumatic stress disorder (PTSD, and social anxiety disorder (social phobia (SAD. Regional changes in cerebral perfusion following SSRI treatment have been shown for all three disorders. The orbitofrontal cortex (OFC (OCD, caudate (OCD, medial pre-frontal/cingulate (OCD, SAD, PTSD, temporal (OCD, SAD, PTSD and, thalamic regions (OCD, SAD are some of those implicated. Some data also suggests that higher perfusion pre-treatment in the anterior cingulate (PTSD, OFC, caudate (OCD and antero-lateral temporal region (SAD predicts subsequent treatment response. This paper further examines the notion of overlap in the neurocircuitry of treatment and indeed treatment response across anxiety disorders with SSRI treatment. Methods Single photon emission computed tomography (SPECT using Tc-99 m HMPAO to assess brain perfusion was performed on subjects with OCD, PTSD, and SAD before and after 8 weeks (SAD and 12 weeks (OCD and PTSD treatment with the SSRI citalopram. Statistical parametric mapping (SPM was used to compare scans (pre- vs post-medication, and responders vs non-responders in the combined group of subjects. Results Citalopram treatment resulted in significant deactivation (p = 0.001 for the entire group in the superior (t = 4.78 and anterior (t = 4.04 cingulate, right thalamus (t = 4.66 and left hippocampus (t = 3.96. Deactivation (p = 0.001 within the left precentral (t = 4.26, right mid-frontal (t = 4.03, right inferior frontal (t = 3.99, left prefrontal (3.81 and right precuneus (t= 3.85 was more marked in treatment responders. No pattern of baseline activation distinguished responders from non-responders to subsequent pharmacotherapy. Conclusions Although each of the anxiety disorders may be mediated by different

  10. High-performance imaging of stem cells using single-photon emissions

    Science.gov (United States)

    Wagenaar, Douglas J.; Moats, Rex A.; Hartsough, Neal E.; Meier, Dirk; Hugg, James W.; Yang, Tang; Gazit, Dan; Pelled, Gadi; Patt, Bradley E.

    2011-10-01

    Radiolabeled cells have been imaged for decades in the field of autoradiography. Recent advances in detector and microelectronics technologies have enabled the new field of "digital autoradiography" which remains limited to ex vivo specimens of thin tissue slices. The 3D field-of-view (FOV) of single cell imaging can be extended to millimeters if the low energy (10-30 keV) photon emissions of radionuclides are used for single-photon nuclear imaging. This new microscope uses a coded aperture foil made of highly attenuating elements such as gold or platinum to form the image as a kind of "lens". The detectors used for single-photon emission microscopy are typically silicon detectors with a pixel pitch less than 60 μm. The goal of this work is to image radiolabeled mesenchymal stem cells in vivo in an animal model of tendon repair processes. Single-photon nuclear imaging is an attractive modality for translational medicine since the labeled cells can be imaged simultaneously with the reparative processes by using the dual-isotope imaging technique. The details our microscope's two-layer gold aperture and the operation of the energy-dispersive, pixellated silicon detector are presented along with the first demonstration of energy discrimination with a 57Co source. Cell labeling techniques have been augmented by genetic engineering with the sodium-iodide symporter, a type of reporter gene imaging method that enables in vivo uptake of free 99mTc or an iodine isotope at a time point days or weeks after the insertion of the genetically modified stem cells into the animal model. This microscopy work in animal research may expand to the imaging of reporter-enabled stem cells simultaneously with the expected biological repair process in human clinical trials of stem cell therapies.

  11. DE-BLURRING SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY IMAGES USING WAVELET DECOMPOSITION

    Directory of Open Access Journals (Sweden)

    Neethu M. Sasi

    2016-02-01

    Full Text Available Single photon emission computed tomography imaging is a popular nuclear medicine imaging technique which generates images by detecting radiations emitted by radioactive isotopes injected in the human body. Scattering of these emitted radiations introduces blur in this type of images. This paper proposes an image processing technique to enhance cardiac single photon emission computed tomography images by reducing the blur in the image. The algorithm works in two main stages. In the first stage a maximum likelihood estimate of the point spread function and the true image is obtained. In the second stage Lucy Richardson algorithm is applied on the selected wavelet coefficients of the true image estimate. The significant contribution of this paper is that processing of images is done in the wavelet domain. Pre-filtering is also done as a sub stage to avoid unwanted ringing effects. Real cardiac images are used for the quantitative and qualitative evaluations of the algorithm. Blur metric, peak signal to noise ratio and Tenengrad criterion are used as quantitative measures. Comparison against other existing de-blurring algorithms is also done. The simulation results indicate that the proposed method effectively reduces blur present in the image.

  12. Strain-Engineered Low-Density InAs Bilayer Quantum Dots for Single Photon Emission

    Institute of Scientific and Technical Information of China (English)

    LI Zhan-Guo; LIU Guo-Jun; LI Lin; FENG Ming; LI Mei; LU Peng; ZOU Yong-Gang; LI Lian-He; GAO Xin

    2010-01-01

    @@ We investigate the growth of strain-engineered low-density InAs bilayer quantum dots(BQDs)on GaAs bymolecular beam epitaxy.Owing to increasing dot size and In composition of the upper QDs,low-density BQDs in a GaAs matrix with an emission wavelength up to 1.4 μm at room temperature are achieved.Such a wavelength is larger than that of conventional QDs in a GaAs matrix(generally of about 1.3 μm).The optical properties of the BQDs are sensitive to annealing temperature used after spacer layer growth.Significant decrease of integrated PL intensity is observed as the annealing temperature increases.At IO K,single photon emission from the BQDs with wavelength around 1.3μm is observed.

  13. Strain-Engineered Low-Density InAs Bilayer Quantum Dots for Single Photon Emission

    International Nuclear Information System (INIS)

    We investigate the growth of strain-engineered low-density InAs bilayer quantum dots (BQDs) on GaAs by molecular beam epitaxy. Owing to increasing dot size and In composition of the upper QDs, low-density BQDs in a GaAs matrix with an emission wavelength up to 1.4 μm at room temperature are achieved. Such a wavelength is larger than that of conventional QDs in a GaAs matrix (generally of about 1.3 μm). The optical properties of the BQDs are sensitive to annealing temperature used after spacer layer growth. Significant decrease of integrated PL intensity is observed as the annealing temperature increases. At 10K, single photon emission from the BQDs with wavelength around 1.3 μm is observed. (condensed matter: structure, mechanical and thermal properties)

  14. Accelerated single photon emission from dye molecule-driven nanoantennas assembled on DNA.

    Science.gov (United States)

    Busson, Mickaël P; Rolly, Brice; Stout, Brian; Bonod, Nicolas; Bidault, Sébastien

    2012-07-17

    A photon interacts efficiently with an atom when its frequency corresponds exactly to the energy between two eigenstates. But at the nanoscale, homogeneous and inhomogeneous broadenings strongly hinder the ability of solid-state systems to absorb, scatter or emit light. By compensating the impedance mismatch between visible wavelengths and nanometre-sized objects, optical antennas can enhance light-matter interactions over a broad frequency range. Here we use a DNA template to introduce a single dye molecule in gold particle dimers that act as antennas for light with spontaneous emission rates enhanced by up to two orders of magnitude and single photon emission statistics. Quantitative agreement between measured rate enhancements and theoretical calculations indicate a nanometre control over the emitter-particle position while 10 billion copies of the target geometry are synthesized in parallel. Optical antennas can thus tune efficiently the photo-physical properties of nano-objects by precisely engineering their electromagnetic environment.

  15. Development of radioiodinated receptor ligands for cerebral single photon emission tomography

    International Nuclear Information System (INIS)

    In the last decade the use of radiolabeled ligands for the imaging of cerebral receptors by emission computed tomography (ECT) has seen rapid growth. The opportunity to routinely perform cerebral single photon emission tomography (SPET) with iodine-123-labeled ligands depends on the availability of receptor ligands into which iodine can be introduced without decreasing the required high target receptor specificity. The use of iodine-123-labeled receptor-specific ligands also depends on the availability of high purity iodine-123 at reasonable costs and the necessary imaging instrumentation. In this paper, the development and current stage of evaluation of various iodine-123-labeled ligands for SPET imaging of dopaminergic, serotonergic and muscarinic acetylcholinergic receptor classes are discussed

  16. Single-photon emission associated with double electron capture in F9+ + C collisions

    CERN Document Server

    Elkafrawy, Tamer; Tanis, John A; Warczak, Andrzej

    2016-01-01

    Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.

  17. Single photon emission computed tomography and albumin colloid imaging of the liver

    International Nuclear Information System (INIS)

    A single photon emission computed tomography (ECT) system using the GE 400T Anger camera with 37 PM tubes and the SPECTS software has been used in the study of liver imaging with Tc-99m albumin colloid and other agents. Patients were injected with 3-4 mCi (ca 120 MBq) of colloid; five standard liver-spleen views and a 64-image ECT study were acquired. A series of normal and abnormal patients have been studied and the data analyzed. The significant change in the technique of ECT imaging is the elliptical motion of the camera head which allows a better approximation of the patient contour and improves the spatial resolution of the images. (Auth.)

  18. Single photon emission computed tomography study of human pulmonary perfusion: preliminary findings

    International Nuclear Information System (INIS)

    Single photon emission computed tomography (SPECT) was performed with 99Tcsup(m)-albumin macroaggregates to study human pulmonary perfusion in healthy subjects and patients with respiratory diseases such as chronic obstructive pulmonary disease (COPD) and lung neoplasms. The reconstructed SPECT data was displayed in coronal, transverse, sagittal plane sections and compared to conventional perfusion scans. The SPECT data gave more complicated anatomical information about the extent of damage and morphology of the pulmonary vascular bed. In healthy subjects and COPD patients, qualitative and quantitative assessment of pulmonary perfusion could be obtained from serial SPECT scans with respect to distribution and relative concentration of the injected radiopharmaceutical. Furthermore, SPECT of pulmonary perfusion has been useful in detecting the extent of damage to the pulmonary circulation. This is useful for the preoperative evaluation and staging of lung cancer. (author)

  19. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs

    International Nuclear Information System (INIS)

    The single photon emission microscope (SPEM) is an instrument developed to obtain high spatial resolution single photon emission computed tomography (SPECT) images of small structures inside the mouse brain. SPEM consists of two independent imaging devices, which combine a multipinhole collimator, a high-resolution, thallium-doped cesium iodide [CsI(Tl)] columnar scintillator, a demagnifying/intensifier tube, and an electron-multiplying charge-coupling device (CCD). Collimators have 300- and 450-µm diameter pinholes on tungsten slabs, in hexagonal arrays of 19 and 7 holes. Projection data are acquired in a photon-counting strategy, where CCD frames are stored at 50 frames per second, with a radius of rotation of 35 mm and magnification factor of one. The image reconstruction software tool is based on the maximum likelihood algorithm. Our aim was to evaluate the spatial resolution and sensitivity attainable with the seven-pinhole imaging device, together with the linearity for quantification on the tomographic images, and to test the instrument in obtaining tomographic images of different mouse organs. A spatial resolution better than 500 µm and a sensitivity of 21.6 counts·s-1·MBq-1 were reached, as well as a correlation coefficient between activity and intensity better than 0.99, when imaging 99mTc sources. Images of the thyroid, heart, lungs, and bones of mice were registered using 99mTc-labeled radiopharmaceuticals in times appropriate for routine preclinical experimentation of <1 h per projection data set. Detailed experimental protocols and images of the aforementioned organs are shown. We plan to extend the instrument's field of view to fix larger animals and to combine data from both detectors to reduce the acquisition time or applied activity

  20. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs

    Energy Technology Data Exchange (ETDEWEB)

    Mejia, J. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Reis, M.A. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Laboratório Interdisciplinar de Neurociências Clínicas, Departamento de Psiquiatria, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Miranda, A.C.C. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Batista, I.R. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Laboratório Interdisciplinar de Neurociências Clínicas, Departamento de Psiquiatria, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Barboza, M.R.F.; Shih, M.C. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Fu, G. [GE Global Research, Schenectady, NY (United States); Chen, C.T. [Department of Radiology, University of Chicago, Chicago, IL (United States); Meng, L.J. [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois, Urbana-Champaign, IL (United States); Bressan, R.A. [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil); Laboratório Interdisciplinar de Neurociências Clínicas, Departamento de Psiquiatria, Universidade Federal de São Paulo, São Paulo, SP (Brazil); Amaro, E. Jr [Hospital Israelita Albert Einstein, Instituto do Cérebro, São Paulo, SP (Brazil)

    2013-11-06

    The single photon emission microscope (SPEM) is an instrument developed to obtain high spatial resolution single photon emission computed tomography (SPECT) images of small structures inside the mouse brain. SPEM consists of two independent imaging devices, which combine a multipinhole collimator, a high-resolution, thallium-doped cesium iodide [CsI(Tl)] columnar scintillator, a demagnifying/intensifier tube, and an electron-multiplying charge-coupling device (CCD). Collimators have 300- and 450-µm diameter pinholes on tungsten slabs, in hexagonal arrays of 19 and 7 holes. Projection data are acquired in a photon-counting strategy, where CCD frames are stored at 50 frames per second, with a radius of rotation of 35 mm and magnification factor of one. The image reconstruction software tool is based on the maximum likelihood algorithm. Our aim was to evaluate the spatial resolution and sensitivity attainable with the seven-pinhole imaging device, together with the linearity for quantification on the tomographic images, and to test the instrument in obtaining tomographic images of different mouse organs. A spatial resolution better than 500 µm and a sensitivity of 21.6 counts·s{sup -1}·MBq{sup -1} were reached, as well as a correlation coefficient between activity and intensity better than 0.99, when imaging {sup 99m}Tc sources. Images of the thyroid, heart, lungs, and bones of mice were registered using {sup 99m}Tc-labeled radiopharmaceuticals in times appropriate for routine preclinical experimentation of <1 h per projection data set. Detailed experimental protocols and images of the aforementioned organs are shown. We plan to extend the instrument's field of view to fix larger animals and to combine data from both detectors to reduce the acquisition time or applied activity.

  1. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs

    Directory of Open Access Journals (Sweden)

    J. Mejia

    2013-11-01

    Full Text Available The single photon emission microscope (SPEM is an instrument developed to obtain high spatial resolution single photon emission computed tomography (SPECT images of small structures inside the mouse brain. SPEM consists of two independent imaging devices, which combine a multipinhole collimator, a high-resolution, thallium-doped cesium iodide [CsI(Tl] columnar scintillator, a demagnifying/intensifier tube, and an electron-multiplying charge-coupling device (CCD. Collimators have 300- and 450-µm diameter pinholes on tungsten slabs, in hexagonal arrays of 19 and 7 holes. Projection data are acquired in a photon-counting strategy, where CCD frames are stored at 50 frames per second, with a radius of rotation of 35 mm and magnification factor of one. The image reconstruction software tool is based on the maximum likelihood algorithm. Our aim was to evaluate the spatial resolution and sensitivity attainable with the seven-pinhole imaging device, together with the linearity for quantification on the tomographic images, and to test the instrument in obtaining tomographic images of different mouse organs. A spatial resolution better than 500 µm and a sensitivity of 21.6 counts·s-1·MBq-1 were reached, as well as a correlation coefficient between activity and intensity better than 0.99, when imaging 99mTc sources. Images of the thyroid, heart, lungs, and bones of mice were registered using 99mTc-labeled radiopharmaceuticals in times appropriate for routine preclinical experimentation of <1 h per projection data set. Detailed experimental protocols and images of the aforementioned organs are shown. We plan to extend the instrument's field of view to fix larger animals and to combine data from both detectors to reduce the acquisition time or applied activity.

  2. Single-Photon Emission at Liquid Nitrogen Temperature from a Single InAs/GaAs Quantum Dot

    Institute of Scientific and Technical Information of China (English)

    DOU Xiu-Ming; SUN Bao-Quan; CHANG Xiu-Ying; XIONG Yong-Hua; HUANG She-Song; NI Hai-Qiao; NIU Zhi-Chuan

    2008-01-01

    We report on the single photon emission from single InAs/GaAs self-assembled Stranski-Krastanow quantum dots up to 80 K under pulsed and continuous wave excitations. At temperature 80 K, the second-order correlation function at zero time delay, g(2)(0), is measured to be 0.422 for pulsed excitation. At the same temperature under continuous wave excitation, the photon antibunching effect is observed. Thus, our experimental results demonstrate a promising potential application of self-assembled InAs/GaAs quantum dots in single photon emission at liquid nitrogen temperature.

  3. Clinical deficits in Huntington disease correlate with reduced striatal uptake on iodine-123 epidepride single-photon emission tomography

    International Nuclear Information System (INIS)

    Huntington disease (HD) is characterized by severe abnormalities in neurotransmitter concentrations and neuroreceptor density. Quantitative changes in dopamine D2 receptors occur in the early stages of HD and may be detectable with functional neuroimaging techniques. The aim of this study was to determine whether dopamine D2 receptor imaging with single-photon emission tomography (SPET) identifies preclinical abnormalities in HD. The study population comprised 32 subjects from families affected by HD: 11 were genetically normal while 21 were genetically positive for HD (seven asymptomatic, six early, three moderate and five advanced findings). Disease severity was determined using a standardized quantitative neurological examination (QNE) and the mini-mental status examination (MMSE). Subjects underwent brain SPET imaging 120 min following intravenous injection of iodine-123 epidepride. Ratios of target (striatal) to nontarget (occipital or whole-brain) uptake were calculated from the reconstructed image data. Striatum to occiput and striatum to whole-brain count ratios correlated negatively with disease stage (P=0.002 and P=0.0002) and QNE (P2 receptor density can be detected with 123I epidepride at moderate or advanced stages of HD. In contrast to other reports, we could not identify abnormalities in clinically unaffected or early stages of HD. (orig.)

  4. Clinical deficits in Huntington disease correlate with reduced striatal uptake on iodine-123 epidepride single-photon emission tomography.

    Science.gov (United States)

    Leslie, W D; Greenberg, C R; Abrams, D N; Hobson, D

    1999-11-01

    Huntington disease (HD) is characterized by severe abnormalities in neurotransmitter concentrations and neuroreceptor density. Quantitative changes in dopamine D(2) receptors occur in the early stages of HD and may be detectable with functional neuroimaging techniques. The aim of this study was to determine whether dopamine D(2) receptor imaging with single-photon emission tomography (SPET) identifies preclinical abnormalities in HD. The study population comprised 32 subjects from families affected by HD: 11 were genetically normal while 21 were genetically positive for HD (seven asymptomatic, six early, three moderate and five advanced findings). Disease severity was determined using a standardized quantitative neurological examination (QNE) and the mini-mental status examination (MMSE). Subjects underwent brain SPET imaging 120 min following intravenous injection of iodine-123 epidepride. Ratios of target (striatal) to nontarget (occipital or whole-brain) uptake were calculated from the reconstructed image data. Striatum to occiput and striatum to whole-brain count ratios correlated negatively with disease stage (P=0.002 and P=0.0002) and QNE (Pepidepride at moderate or advanced stages of HD. In contrast to other reports, we could not identify abnormalities in clinically unaffected or early stages of HD. PMID:10552088

  5. Enhanced single-photon emission from a diamond–silver aperture

    KAUST Repository

    Choy, Jennifer T.

    2011-10-09

    Solid-state quantum emitters, such as the nitrogen-vacancy centre in diamond, are robust systems for practical realizations of various quantum information processing protocols2-5 and nanoscale magnetometry schemes6,7 at room temperature. Such applications benefit from the high emission efficiency and flux of single photons, which can be achieved by engineering the electromagnetic environment of the emitter. One attractive approach is based on plasmonic resonators8-13, in which sub-wavelength confinement of optical fields can strongly modify the spontaneous emission of a suitably embedded dipole despite having only modest quality factors. Meanwhile, the scalability of solid-state quantum systems critically depends on the ability to control such emitterg-cavity interaction in a number of devices arranged in parallel. Here, we demonstrate a method to enhance the radiative emission rate of single nitrogen-vacancy centres in ordered arrays of plasmonic apertures that promises greater scalability over the previously demonstrated bottom-up approaches for the realization of on-chip quantum networks. © 2011 Macmillan Publishers Limited. All rights reserved.

  6. The distribution of cerebral muscarinic acetylcholine receptors in vivo in patients with dementia. A controlled study with 123IQNB and single photon emission computed tomography

    International Nuclear Information System (INIS)

    A high-affinity muscarinic receptor antagonist, 123IQNB (3-quinuclidinyl-4-iodobenzilate labeled with iodine 123), was used with single photon emission computed tomography to image muscarinic acetylcholine receptors in 14 patients with dementia and in 11 healthy controls. High-resolution single photon emission computed tomographic scanning was performed 21 hours after the intravenous administration of approximately 5 mCi of IQNB. In normal subjects, the images of retained ligand showed a consistent regional pattern that correlated with postmortem studies of the relative distribution of muscarinic receptors in the normal human brain, having high radioactivity counts in the basal ganglia, occipital cortex, and insular cortex, low counts in the thalamus, and virtually no counts in the cerebellum. Eight of 12 patients with a clinical diagnosis of Alzheimer's disease had obvious focal cortical defects in either frontal or posterior temporal cortex. Both patients with a clinical diagnosis of Pick's disease had obvious frontal and anterior temporal defects. A region of interest statistical analysis of relative regional activity revealed a significant reduction bilaterally in the posterior temporal cortex of the patients with Alzheimer's disease compared with controls. This study demonstrates the practicability of acetylcholine receptor imaging with 123IQNB and single photon emission computed tomography. The data suggest that focal abnormalities in muscarinic binding in vivo may characterize some patients with Alzheimer's disease and Pick's disease, but further studies are needed to address questions about partial volume artifacts and receptor quantification

  7. Electrically driven single photon emission from a CdSe/ZnSSe single quantum dot at 200 K

    Energy Technology Data Exchange (ETDEWEB)

    Quitsch, Wolf; Kümmell, Tilmar; Bacher, Gerd [Werkstoffe der Elektrotechnik and CENIDE, Universität Duisburg-Essen, Bismarckstraße 81, 47057 Duisburg (Germany); Gust, Arne; Kruse, Carsten; Hommel, Detlef [Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28334 Bremen (Germany)

    2014-09-01

    High temperature operation of an electrically driven single photon emitter based on a single epitaxial quantum dot is reported. CdSe/ZnSSe/MgS quantum dots are embedded into a p-i-n diode architecture providing almost background free excitonic and biexcitonic electroluminescence from individual quantum dots through apertures in the top contacts. Clear antibunching with g{sup 2}(τ = 0) = 0.28 ± 0.20 can be tracked up to T = 200 K, representing the highest temperature for electrically triggered single photon emission from a single quantum dot device.

  8. Few-view single photon emission computed tomography (SPECT) reconstruction based on a blurred piecewise constant object model

    DEFF Research Database (Denmark)

    Wolf, Paul A.; Jørgensen, Jakob Sauer; Schmidt, Taly G.;

    2013-01-01

    A sparsity-exploiting algorithm intended for few-view Single Photon Emission Computed Tomography (SPECT) reconstruction is proposed and characterized. The algorithm models the object as piecewise constant subject to a blurring operation. To validate that the algorithm closely approximates the true...

  9. A quantum dot single-photon source with on-the-fly all-optical polarization control and timed emission

    OpenAIRE

    Heinze, Dirk; Breddermann, Dominik; Zrenner, Artur; Schumacher, Stefan

    2015-01-01

    Sources of single photons are key elements in the study of basic quantum optical concepts and applications in quantum information science. Among the different sources available, semiconductor quantum dots excel with their straight forward integrability in semiconductor based on-chip solutions and the potential that photon emission can be triggered on demand. Usually, the photon emission event is part of a cascaded biexciton-exciton emission scheme. Important properties of the emitted photon s...

  10. Intracranial blood flow measured with single photon emission computer tomography (SPECT) during transient -6 degrees head-down tilt.

    Science.gov (United States)

    Satake, H; Konishi, T; Kawashima, T; Matsunami, K; Uno, T; Imai, S; Yamada, H; Hirakawa, C

    1994-02-01

    Regional cerebral blood flow (CBF) during a transient head-down tilt of -6 degrees (-6 degrees HDT) was measured with single photon emission computer tomography (SPECT). CBF was measured and averaged for both sides of the brain areas; e.g., the bilateral anterior cerebral artery (bACA) area, the middle cerebral artery (bMCA) area, the posterior cerebral artery (bPCA) area, bilateral basal ganglia, and the cerebellum. Among these areas, a significant increase in CBF was observed in the basal ganglia and the cerebellum during -6 degrees HDT compared to pre-HDT. When CBF was measured separately in the left or right brain area, these significances disappeared, although a trend of increase or decrease was still observable. A trend of increase was observed in the left anterior cerebral artery (IACA) area, the right middle cerebral artery (rMCA) area, the right posterior cerebral artery (rPCA) area, the left and right basal ganglia, and the cerebellum. In rACA, IMCA and IPCA areas, a slight decrease in CBF was observed. At the same time, cardiac parameters were measured. Heart rate (HR), stroke volume (SV) and cardiac output (CO) did not change significantly, although SV slightly increased and HR slightly decreased during -6 degrees HDT.

  11. Single Photon Emission Computed Tomography (SPECT) Experience with (S)-5-[123I]iodo-3-(2-azetidinylmethoxy)pyridine (5-[123I]IA) in the Living Human Brain of Smokers and Nonsmokers

    OpenAIRE

    BRAŠIĆ, JAMES ROBERT; Zhou, Yun; MUSACHIO, JOHN L.; Hilton, John; Fan, Hong; CRABB, ANDREW; Endres, Christopher J.; REINHARDT, MELVIN J.; DOGAN, AHMET S.; Alexander, Mohab; Rousset, Olivier; MARIS, MARIKA A.; GALECKI, JEFFREY; Nandi, Ayon; Wong, Dean F.

    2009-01-01

    (S)-5-[123I]iodo-3-(2-azetidinylmethoxy)pyridine (5-[123I]IA), a novel potent radioligand for high-affinity α4β2* neuronal nicotinic acetylcholine receptors (nAChRs), provides a means to evaluate the density and the distribution of nAChRs in the living human brain. We sought in healthy adult smokers and nonsmokers to (1) evaluate the safety, tolerability, and efficacy of 5-[123I]IA in an open nonblind trial and (2) to estimate the density and distribution of α4β2* nAChRs in the brain. Single ...

  12. QUANTUM CRYPTOGRAPHY: Single Photons.

    Science.gov (United States)

    Benjamin, S

    2000-12-22

    Quantum cryptography offers the potential of totally secure transfer of information, but as Benjamin discusses in this Perspective, its practical implementation hinges on being able to generate single photons (rather than two or more) at a time. Michler et al. show how this condition can be met in a quantum dot microdisk structure. Single molecules were also recently shown to allow controlled single-photon emission.

  13. 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.

  14. 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

  15. Thallium-201 single-photon emission tomography in the treatment follow-up of nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    In order to assess the usefulness of thallium-201 single-photon emission tomography (SPET) in the treatment follow-up of nasopharyngeal carcinoma (NPC), a total of 75 201Tl SPET studies were performed in 18 patients with histologically proven NPC. The findings were compared with those of magnetic resonance imaging (MRI) before and after therapy. Four patients received radiotherapy alone while the other 14 received concurrent chemo-radiotherapy. Treatment response was classified as complete (CR) or partial (PR) based on the findings of MRI and 201Tl SPET. Intense 201Tl uptake by the tumour was seen in all 18 patients before treatment. After treatment, MRI showed seven CRs and 11 PRs, whereas 201Tl SPET showed 13 CRs and five PRs. In 12 patients, the results of 201Tl SPET were in agreement with those of MRI. In six patients MRI showed PR but 201Tl showed CR. Follow-up (mean 10.6 months) MRI and 201Tl SPET studies of these six patients revealed that tumour gradually decreased and finally vanished in three patients. This preliminary study indicates that 201Tl SPET has potential in the assessment of early response to treatment of patients with NPC when compared with MRI. (orig.)

  16. The identification of spinal pathology in chronic low back pain using single photon emission computed tomography

    International Nuclear Information System (INIS)

    Single photon emission computed tomography (SPECT) findings were investigated in 80 consecutive patients (aged 18-70 years, median 44) referred to a rheumatology outpatient clinic with low back pain persisting for more than 3 months. Lesions of the lumbar spine were demonstrated in 60% of patients using SPECT but in only 35% with planar imaging. Fifty-one per cent of all lesions were only detected by SPECT, and lesions visualized on SPECT could be precisely localized to the vertebral body, or different parts of the posterior elements. Fifty per cent of lesions involved the facetal joints of which almost 60% were identified on SPECT alone. X-rays of the lumbar spine, with posterior oblique views, failed to demonstrate abnormalities corresponding to almost all SPECT posterior element lesions although it identified abnormalities corresponding to over 60% of anterior SPECT lesions. Computed tomography (CT) was performed in 30 patients with a SPECT lesion and sites of facetal joint activity corresponded to facetal osteoarthritis in 82%. (author)

  17. Multicenter evaluation of single-photon emission computed tomography quantification with third-party reconstruction software.

    Science.gov (United States)

    Kangasmaa, Tuija S; Constable, Chris; Hippeläinen, Eero; Sohlberg, Antti O

    2016-09-01

    Reliable and reproducible quantification is essential in many clinical situations. Previously, single-photon emission computed tomography (SPECT) has not been considered a quantitative imaging modality, but recent advances in reconstruction algorithm development have made SPECT quantitative. In this study, we investigate the reproducibility of SPECT quantification with phantoms in a multicenter setting using novel third-party reconstruction software. A total of five hospitals and eight scanners (three GE scanners and five Siemens scanners) participated in the study. A Jaszczak phantom without inserts was used to calculate counts to activity concentration conversion factors. The quantitative accuracy was tested using the NEMA-IEC phantom with six spherical inserts (diameters from 10 to 37 mm) filled to an 8 : 1 insert-background concentration ratio. Phantom studies were reconstructed at one central location using HERMES HybridRecon applying corrections for attenuation, collimator-detector response, and scatter. Spherical volumes of interest with the same diameter as the inserts were drawn on the images and recovery coefficients for the spheres were calculated. The coefficient of variation (CoV) of the NEMA-IEC phantom recovery coefficients ranged from ∼19 to 5% depending on the insert diameter so that the lowest CoV was obtained with the largest spheres. The intersite CoV was almost equal to intrasite CoV. In conclusion, quantitative SPECT is reproducible in a multicenter setting with third-party reconstruction software. PMID:27128824

  18. Single photon emission computed tomography in the diagnosis of Alzheimer`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Hanyu, Haruo; Asano, Tetsuichi; Abe, Shin`e; Arai, Hisayuki; Iwamoto, Toshihiko; Takasaki, Masaru; Shindo, Hiroaki; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    1997-06-01

    Studies with single photon emission computed tomography (SPECT) have shown temporoparietal (TP) hypoperfusion in patients with Alzheimer`s disease (AD). We evaluated the utility of this findings in the diagnosis of AD. SPECT images with {sup 123}I-iodoamphetamine were analyzed qualitatively by a rater without knowledge of the subject`s clinical status. Sixty-seven of 302 consecutive patients were judged as having TP hypoperfusion by SPECT imaging. This perfusion pattern was observed in 44 of 51 patients with AD, in 5 with mixed dementia, 8 with cerebrovascular disease (including 5 with dementia), 4 with Parkinson`s disease (including 2 with dementia), 1 with normal pressure hydrocephalus, 1 with slowly progressive aphasia, 1 with progressive autonomic failure, 2 with age-associated memory impairment, and 1 with unclassified dementia. The sensitivity for AD was 86.3% (44 of 51 AD), and the specificity was 91.2% (229 of 251 non-AD). Next, we looked for differences in perfusion images between patients with AD and without AD. Some patients without AD had additional hypoperfusion beyond TP areas: deep gray matter hypoperfusion and diffuse frontal hypoperfusion, which could be used to differentiate them from the patients with AD. Others could not be distinguished from patients with AD by their perfusion pattern. Although patients with other cerebral disorders occasionally have TP hypoperfusion, this finding makes the diagnosis of AD very likely. (author)

  19. Dynamic single photon emission computed tomography of Tl-201 with exercise loading

    International Nuclear Information System (INIS)

    Single photon emission computed tomography (SPECT) with Tl-201 has been reported to provide accurate means for diagnosis of coronary artery disease (CAD). The purpose of this study is to examine the serial changes in regional myocardial activity of Tl-201 injected during exercise loading in CAD using a multidetector SPECT system. Four cases without coronary stenosis (N) and 17 patients with CAD including 9 cases with prior myocardial infarction (MI) were studied. Tl-201 was injected during submaximal exercise loading with a bicycle ergometer. Serial dynamic SPECT scan was performed every 5 min until 30 min after injection, followed by additional 3 scans for 10 min at 1 hr, 2 hr and 3 hr after injection. These SPECT images were corrected for the acquisition time, but no corrections were made for photon attenuation and scattering. N revealed uniform distribution throughout the study, and rapid washout was observed from the early period in 3/4 cases (10 to 24 % for initial 25 min). CAD showed various patterns of abnormal distribution and washout. In addition, the changes in regional distribution of Tl-201 were observed during the early period. These preliminary results indicate the significance of the early washout during the 30 min after injection of Tl-201, and careful consideration should be taken in calculating the washout rate by a conventional SPECT system with a rotating gamma camera. (author)

  20. Two-dimensional restoration of single photon emission computed tomography images using the Kalman filter

    International Nuclear Information System (INIS)

    The discrete filtered backprojection (DFBP) algorithm used for the reconstruction of single photon emission computed tomography (SPECT) images affects image quality because of the operations of filtering and discretization. The discretization of the filtered backprojection process can cause the modulation transfer function (MTF) of the SPECT imaging system to be anisotropic and nonstationary, especially near the edges of the camera's field of view. The use of shift-invariant restoration techniques fails to restore large images because these techniques do not account for such variations in the MTF. This study presents the application of a two-dimensional (2-D) shift-variant Kalman filter for post-reconstruction restoration of SPECT slices. This filter was applied to SPECT images of a hollow cylinder phantom; a resolution phantom; and a large, truncated cone phantom containing two types of cold spots, a sphere, and a triangular prism. The images were acquired on an ADAC GENESYS camera. A comparison was performed between results obtained by the Kalman filter and those obtained by shift-invariant filters. Quantitative analysis of the restored images performed through measurement of root mean squared errors shows a considerable reduction in error of Kalman-filtered images over images restored using shift-invariant methods

  1. Advances in pinhole and multi-pinhole collimators for single photon emission computed tomography imaging.

    Science.gov (United States)

    Islamian, Jalil Pirayesh; Azazrm, AhmadReza; Mahmoudian, Babak; Gharapapagh, Esmail

    2015-01-01

    The collimator in single photon emission computed tomography (SPECT), is an important part of the imaging chain. One of the most important collimators that used in research, preclinical study, small animal, and organ imaging is the pinhole collimator. Pinhole collimator can improve the tradeoff between sensitivity and resolution in comparison with conventional parallel-hole collimator and facilities diagnosis. However, a major problem with pinhole collimator is a small field of view (FOV). Multi-pinhole collimator has been investigated in order to increase the sensitivity and FOV with a preserved spatial resolution. The geometry of pinhole and multi-pinhole collimators is a critical factor in the image quality and plays a key role in SPECT imaging. The issue of the material and geometry for pinhole and multi-pinhole collimators have been a controversial and much disputed subject within the field of SPECT imaging. On the other hand, recent developments in collimator optimization have heightened the need for appropriate reconstruction algorithms for pinhole SPECT imaging. Therefore, iterative reconstruction algorithms were introduced to minimize the undesirable effect on image quality. Current researches have focused on geometry and configuration of pinhole and multi-pinhole collimation rather than reconstruction algorithm. The lofthole and multi-lofthole collimator are samples of novel designs. The purpose of this paper is to provide a review on recent researches in the pinhole and multi-pinhole collimators for SPECT imaging. PMID:25709537

  2. Single-photon emission computed tomographic findings and motor neuron signs in amyotrophic lateral sclerosis

    International Nuclear Information System (INIS)

    123I-amphetamine-single photon emission computed tomography (SPECT) was performed on 16 patients with amyotrophic lateral sclerosis (ALS) to investigate the correlation between regional cerebral blood flow (rCBF) and upper motor neuron signs. Significant decreased blood flow less than 2 SDs below the mean of controls was observed in the frontal lobe in 4 patients (25%) and in the frontoparietal lobe including the cortical motor area in 4 patients, respectively. The severity of extermity muscular weakness was significantly correlate with decrease in blood flow through the frontal lobe (p<0.05) and through the frontoparietal lobe (p<0.001). A significant correlation was also noted to exist between the severity of bulbar paralysis and decrease in blood flow through the frontoparietal lobe. No correlation, however, was observed between rCBF and severity of spasticity, presence or absence of Babinski's sign and the duration of illness. Although muscular weakness in the limbs and bulbar paralysis are not pure upper motor neuron signs, the observed reduction in blood flow through the frontal or frontoparietal lobes appears to reflect extensive progression of functional or organic lesions of cortical neurons including the motor area. (author)

  3. Regional cerebral blood flow analysis of vascular dementia by the single photon emission computed tomography

    International Nuclear Information System (INIS)

    In order to evaluate the relationship between the regional cerebral blood flow (CBF) and cerebrovascular dementia, eleven patients with vascular dementia and eight patients with non-demented infarction were studied and regional CBF were measured quantitatively with single photon emission computed tomography (SPECT) by using N-isopropyl-p-(I-123) iodoamphetamine. All cases were basal infarction and vascular dementia were diagnosed by less than 21.5 of the Hasegawa's dementia score and more than 7 of Hachinsk's ischemic score. The results of the present study were as follows: (1) Cerebrovascular dementia showed lower mean CBF value compared with non-demented group. (2) Regional CBF of bilateral frontal areas and affected basal ganglia were significantly reduced than occipital area in the dementia group. (3) A comparison of regional CBF and the Hasegawa's dementia score revealed a statistically significant correlation at the bilateral frontal areas in the dementia group. It is possible that measuring the regional CBF quantitatively by IMP-SPECT is useful for clinical analysis of vascular dementia. (author)

  4. Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography

    Science.gov (United States)

    Wong, Ka-Kit; Gandhi, Arpit; Viglianti, Benjamin L; Fig, Lorraine M; Rubello, Domenico; Gross, Milton D

    2016-01-01

    AIM: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders. METHODS: We performed MEDLINE and PubMed searches using the terms: “SPECT/CT”; “functional anatomic mapping”; “transmission emission tomography”; “parathyroid adenoma”; “thyroid cancer”; “neuroendocrine tumor”; “adrenal”; “pheochromocytoma”; “paraganglioma”; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology. RESULTS: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for 99mTc-sestamibi parathyroid scintigraphy and 99mTc-pertechnetate thyroid scintigraphy, 123I- or 131I-radioiodine for staging of differentiated thyroid carcinoma, 111In- and 99mTc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, 131I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and 123I- or 131I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma. CONCLUSION: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy

  5. Perfusion single photon emission computed tomography in a mouse model of neurofibromatosis type 1: towards a biomarker of neurologic deficits.

    Science.gov (United States)

    Apostolova, Ivayla; Niedzielska, Dagmara; Derlin, Thorsten; Koziolek, Eva J; Amthauer, Holger; Salmen, Benedikt; Pahnke, Jens; Brenner, Winfried; Mautner, Victor F; Buchert, Ralph

    2015-08-01

    Neurofibromatosis type 1 (NF1) is a single-gene disorder affecting neurologic function in humans. The NF1+/- mouse model with germline mutation of the NF1 gene presents with deficits in learning, attention, and motor coordination, very similar to NF1 patients. The present study performed brain perfusion single-photon emission computed tomography (SPECT) in NF1+/- mice to identify possible perfusion differences as surrogate marker for altered cerebral activity in NF1. Cerebral perfusion was measured with hexamethyl-propyleneamine oxime (HMPAO) SPECT in NF1+/- mice and their wild-type littermates longitudinally at juvenile age and at young adulthood. Histology and immunohistochemistry were performed to test for structural changes. There was increased HMPAO uptake in NF1 mice in the amygdala at juvenile age, which reduced to normal levels at young adulthood. There was no genotype effect on thalamic HMPAO uptake, which was confirmed by ex vivo measurements of F-18-fluorodeoxyglucose uptake in the thalamus. Morphologic analyses showed no major structural abnormalities. However, there was some evidence of increased density of microglial somata in the amygdala of NF1-deficient mice. In conclusion, there is evidence of increased perfusion and increased density of microglia in juvenile NF1 mice specifically in the amygdala, both of which might be associated with altered synaptic plasticity and, therefore, with cognitive deficits in NF1. PMID:25785829

  6. Artificial neural networks that use single-photon emission tomography to identify patients with probable Alzheimer's disease

    International Nuclear Information System (INIS)

    Single-photon emission tomographic (SPET) images using technetium-99m labelled hexamethylpropylene amine oxime were obtained from 97 patients diagnosed as having Alzheimer's disease, as well as from a comparison group of 64 normal subjects. Multiple linear regression was used to predict subject type (Alzheimer's vs comparison) using scintillation counts from 14 different brain regions as predictors. These results were disappointing: the regression equation accounted for only 33.5% of the variance between subjects. However, the same data were also used to train parallel distributed processing (PDP) networks of different sizes to classify subjects. In general, the PDP networks accounted for substantially more (up to 95%) of the variance in the data, and in many instances were able to distinguish perfectly between the two subjects. These results suggest two conclusions. First, SPET images do provide sufficient information to distinguish patients with Alzheimer's disease from a normal comparison group. Second, to access this diagnostic information, it appears that one must take advantage of the ability of PDP networks to detect higher-order nonlinear relationships among the predictor variables. (orig.)

  7. Single photon emission computed tomography before and after treatment of anxiety using a selective serotonin reuptake inhibitor

    International Nuclear Information System (INIS)

    Background: The selective serotonin reuptake inhibitors (SSRIs) are currently recommended as first line medications for a number of different anxiety disorders, including obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), and social anxiety disorder (social phobia) (SAD). This raises the question of what effects these agents have on the functional neuroanatomy of anxiety disorders. Methods: Single photon emission computed tomography (SPECT) brain scanning was undertaken in patients with OCD, PTSD, and SAD before and after treatment with citalopram, the most selective of the SSRIs. Statistical parametric mapping (SPM) was used to compare scans (pre- vs post-medication, and responders vs nonresponders) in the combined group of subjects. Results: Citalopram pharmacotherapy resulted in significant deactivation within anterior and superior cingulate and left hippocampus. Deactivation within the anterior cingulate, left paracingular cortex, and right inferior frontal cortex was more marked in treatment responders. Baseline activation did not, however, predict response to pharmacotherapy. Conclusion: Although each of the anxiety disorders may be mediated by different neurocircuits, there are some overlaps in the functional neuroanatomy of their response to SSRI treatment. The current data is consistent with previous work demonstrating the importance of limbic circuits in this spectrum of disorders. These play a crucial role in cognitive-affective processing, and are innervated by serotonergic neurons

  8. Clinical deficits in Huntington disease correlate with reduced striatal uptake on iodine-123 epidepride single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Leslie, W.D.; Abrams, D.N.; Hobson, D. [Manitoba Univ., Winnipeg, MB (Canada); Dept. of Medicine, St. Boniface General Hospital, Winnipeg (Canada); Greenberg, C.R. [Manitoba Univ., Winnipeg, MB (Canada)

    1999-11-01

    Huntington disease (HD) is characterized by severe abnormalities in neurotransmitter concentrations and neuroreceptor density. Quantitative changes in dopamine D{sub 2} receptors occur in the early stages of HD and may be detectable with functional neuroimaging techniques. The aim of this study was to determine whether dopamine D{sub 2} receptor imaging with single-photon emission tomography (SPET) identifies preclinical abnormalities in HD. The study population comprised 32 subjects from families affected by HD: 11 were genetically normal while 21 were genetically positive for HD (seven asymptomatic, six early, three moderate and five advanced findings). Disease severity was determined using a standardized quantitative neurological examination (QNE) and the mini-mental status examination (MMSE). Subjects underwent brain SPET imaging 120 min following intravenous injection of iodine-123 epidepride. Ratios of target (striatal) to nontarget (occipital or whole-brain) uptake were calculated from the reconstructed image data. Striatum to occiput and striatum to whole-brain count ratios correlated negatively with disease stage (P=0.002 and P=0.0002) and QNE (P<0.002 and P=0.0002), and positively with the MMSE (P=0.001 and P<0.001). Uptake was significantly reduced in the moderate-advanced subjects but was still normal for the asymptomatic and early symptomatic stages. It is concluded that reductions in striatal dopamine D{sub 2} receptor density can be detected with {sup 123}I epidepride at moderate or advanced stages of HD. In contrast to other reports, we could not identify abnormalities in clinically unaffected or early stages of HD. (orig.)

  9. A Study on Determination of an Optimized Detector for Single Photon Emission Computed Tomography.

    Science.gov (United States)

    Khoshakhlagh, Mohammad; Islamian, Jalil Pirayesh; Abedi, Mohammad; Mahmoudian, Babak; Mardanshahi, Ali Reza

    2016-01-01

    The detector is a critical component of the single photon emission computed tomography (SPECT) imaging system for giving accurate information from the exact pattern of radionuclide distribution in the target organ. The SIMIND Monte Carlo program was utilized for the simulation of a Siemen's dual head variable angle SPECT imaging system with a low energy high resolution (LEHR) collimator. The Planar and SPECT scans for a (99m)Tc point source and a Jaszczak Phantom with the both experiment and simulated systems were prepared and after verification and validation of the simulated system, the similar scans of the phantoms were compared (from the point of view of the images' quality), namely, the simulated system with the detectors including bismuth germanate (BGO), yttrium aluminum garnet (YAG:Ce), Cerium-doped yttrium aluminum garnet (YAG:Ce), yttrium aluminum perovslite (YAP:Ce), lutetium aluminum garnet (LuAG:Ce), cerium activated lanthanum bromide (LaBr3), cadmium zinc telluride (CZT), and sodium iodide activated with thallium [NaI(Tl)]. The parameters of full width at half maximum (FWHM), energy and special resolution, sensitivity, and also the comparison of images' quality by the structural similarity (SSIM) algorithm with the Zhou Wang and Rouse/Hemami methods were analyzed. FWHMs for the crystals were calculated at 13.895, 14.321, 14.310, 14.322, 14.184, and 14.312 keV and the related energy resolutions obtained 9.854, 10.229, 10.221, 10.230, 10.131, and 10.223 %, respectively. Finally, SSIM indexes for comparison of the phantom images were calculated at 0.22172, 0.16326, 0.18135, 0.17301, 0.18412, and 0.20433 as compared to NaI(Tl). The results showed that BGO and LuAG: Ce crystals have high sensitivity and resolution, and better image quality as compared to other scintillation crystals. PMID:26912973

  10. Phantom evaluation of simultaneous thallium-201/technetium-99m acquisition in single-photon emission tomography

    International Nuclear Information System (INIS)

    This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70±10% keV, 140±10% keV, 100±10% KeV, and 103±16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered 99mTc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered 99mTc counts that were comparable to the primary 201Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding 201Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered 99mTc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered 99mTc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous 201Tl/99mTc acquisition in clinical practice. (orig.). With 6 figs., 3 tabs

  11. SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY STUDY OF REGIONAL CEREBRAL BLOOD FLOW IN PATIENTS WITH HEMISPATIAL NEGLECT

    Institute of Scientific and Technical Information of China (English)

    尹雅芙; 任艳; 李亚明

    2003-01-01

    Objective.To explore the correlations between the occurrence and severity of neglect and the region,range or extent of the decrease in regional cerebral blood flow(rCBF). Methods. Nineteen dextromanual patients who were diagnosed as unilateral stroke clinically and hemispatial neglect by a neglect test battery received single photon emission computed tomography(SPECT) scans. Results. On images,the damages of patients with neglect were seen most frequently in the frontal cortex,and then in turn in the parietal cortex,occipital cortex,temporal cortex,basal ganglia and thalamus. Most patients with neglect had two or more regions damaged. The most significant region was temporal-parietal-occipi-tal(TPO)junction. The correlation coefficient between rCBF and the severity of neglect was -0.34(t=-1.5,P>0.05),and that between the decrease percentage of rCBF and the severity of neglect was 0.34(t=1.47,P>0.05). The correlation coefficients between the range,number of foci,the flow deficit size and the severity of neglect were 0.71(t=4.13,P<0.01),0.70(t=4.07,P<0.01)and 0.64(t=3.40, P<0.01),respectively. Conclusions. The severity of neglect correlates with rCBF and the decrease percentage of rCBF insignificantly,but correlates positively with the range,number of foci and the flow deficit size significantly. Hemispatial neglect is caused by the damage of multiple sites and combined damage results in more severe neglect.

  12. Safety of ventilation/perfusion single photon emission computed tomography for pulmonary embolism diagnosis

    International Nuclear Information System (INIS)

    The aim of this management outcome study was to assess the safety of ventilation/perfusion single photon emission computed tomography (V/Q SPECT) for the diagnosis of pulmonary embolism (PE) using for interpretation the criteria proposed in the European Association of Nuclear Medicine (EANM) guidelines for V/Q scintigraphy. A total of 393 patients with clinically suspected PE referred to the Nuclear Medicine Department of Brest University Hospital from April 2011 to March 2013, with either a high clinical probability or a low or intermediate clinical probability but positive D-dimer, were retrospectively analysed. V/Q SPECT were interpreted by the attending nuclear medicine physician using a diagnostic cut-off of one segmental or two subsegmental mismatches. The final diagnostic conclusion was established by the physician responsible for patient care, based on clinical symptoms, laboratory test, V/Q SPECT and other imaging procedures performed. Patients in whom PE was deemed absent were not treated with anticoagulants and were followed up for 3 months. Of the 393 patients, the prevalence of PE was 28 %. V/Q SPECT was positive for PE in 110 patients (28 %) and negative in 283 patients (72 %). Of the 110 patients with a positive V/Q SPECT, 78 (71 %) had at least one additional imaging test (computed tomography pulmonary angiography or ultrasound) and the diagnosis of PE was eventually excluded in one patient. Of the 283 patients with a negative V/Q SPECT, 74 (26 %) patients had another test. The diagnosis of PE was finally retained in one patient and excluded in 282 patients. The 3-month thromboembolic risk in the patients not treated with anticoagulants was 1/262: 0.38 % (95 % confidence interval 0.07-2.13). A diagnostic management including V/Q SPECT interpreted with a diagnostic cut-off of ''one segmental or two subsegmental mismatches'' appears safe to exclude PE. (orig.)

  13. Development of correction methods for variable pinhole single-photon emission computed tomography

    Science.gov (United States)

    Bae, S.; Bae, J.; Lee, H.; Lee, K.

    2016-02-01

    We propose a novel pinhole collimator in which the pinhole shape can be changed in real-time, and a new single-photon emission computed tomography (SPECT) system that utilizes this variable pinhole (VP) collimator. The acceptance angle and distance between the collimator and the object of VP SPECT are varied so that the optimum value of the region-of-interest (ROI) can be obtained for each rotation angle. Because of these geometrical variations, new correction methods are required for image reconstruction. In this study, we developed two correction methods. The first is the sensitivity-correction algorithm, which minimizes the variation of a system matrix caused by varying the acceptance angle for each rotation angle. The second is the acquisition-time-correction method, which reduces the variation of uniformity caused by varying the distance between the collimator and the object for each rotation angle. A 3D maximum likelihood expectation maximization (MLEM) algorithm was applied to image reconstruction, and two digital phantoms were studied to evaluate the resolution and sensitivity of the images obtained using the proposed methods. The images obtained by using the proposed correction methods show higher uniformity and resolution than those obtained without using these methods. In particular, the results of the resolution phantom study show that hot rods (0.8-mm-diameter) can be clearly distinguished using the proposed correction methods. A quantitative analysis of the ROI phantom revealed that the mean square error (MSE) was 0.42 without the acquisition-time-correction method, and 0.04 with the acquisition-time-correction method. The MSEs of the resolution phantom without and with the acquisition-time-correction method were calculated as 55.14 and 14.69, respectively.

  14. Development of correction methods for variable pinhole single-photon emission computed tomography

    International Nuclear Information System (INIS)

    We propose a novel pinhole collimator in which the pinhole shape can be changed in real-time, and a new single-photon emission computed tomography (SPECT) system that utilizes this variable pinhole (VP) collimator. The acceptance angle and distance between the collimator and the object of VP SPECT are varied so that the optimum value of the region-of-interest (ROI) can be obtained for each rotation angle. Because of these geometrical variations, new correction methods are required for image reconstruction. In this study, we developed two correction methods. The first is the sensitivity-correction algorithm, which minimizes the variation of a system matrix caused by varying the acceptance angle for each rotation angle. The second is the acquisition-time-correction method, which reduces the variation of uniformity caused by varying the distance between the collimator and the object for each rotation angle. A 3D maximum likelihood expectation maximization (MLEM) algorithm was applied to image reconstruction, and two digital phantoms were studied to evaluate the resolution and sensitivity of the images obtained using the proposed methods. The images obtained by using the proposed correction methods show higher uniformity and resolution than those obtained without using these methods. In particular, the results of the resolution phantom study show that hot rods (0.8-mm-diameter) can be clearly distinguished using the proposed correction methods. A quantitative analysis of the ROI phantom revealed that the mean square error (MSE) was 0.42 without the acquisition-time-correction method, and 0.04 with the acquisition-time-correction method. The MSEs of the resolution phantom without and with the acquisition-time-correction method were calculated as 55.14 and 14.69, respectively

  15. Safety of ventilation/perfusion single photon emission computed tomography for pulmonary embolism diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Le Roux, Pierre-Yves; Palard, Xavier; Robin, Philippe; Abgral, Ronan; Querellou, Solene; Salaun, Pierre-Yves [Universite Europeenne de Bretagne, Brest (France); Universite de Brest, Brest (France); CHRU de la Cavale Blanche, Service de medecine nucleaire, Brest (France); Delluc, Aurelien; Couturaud, Francis [Universite Europeenne de Bretagne, Brest (France); Universite de Brest, Brest (France); CHRU de la Cavale Blanche, Departement de medecine interne et de pneumologie, Brest (France); Le Gal, Gregoire [Universite Europeenne de Bretagne, Brest (France); University of Ottawa, Ottawa Hospital Research Institute, Ottawa (Canada); CHRU de la Cavale Blanche, Departement de medecine interne et de pneumologie, Brest (France); Universite de Brest, Brest (France)

    2014-10-15

    The aim of this management outcome study was to assess the safety of ventilation/perfusion single photon emission computed tomography (V/Q SPECT) for the diagnosis of pulmonary embolism (PE) using for interpretation the criteria proposed in the European Association of Nuclear Medicine (EANM) guidelines for V/Q scintigraphy. A total of 393 patients with clinically suspected PE referred to the Nuclear Medicine Department of Brest University Hospital from April 2011 to March 2013, with either a high clinical probability or a low or intermediate clinical probability but positive D-dimer, were retrospectively analysed. V/Q SPECT were interpreted by the attending nuclear medicine physician using a diagnostic cut-off of one segmental or two subsegmental mismatches. The final diagnostic conclusion was established by the physician responsible for patient care, based on clinical symptoms, laboratory test, V/Q SPECT and other imaging procedures performed. Patients in whom PE was deemed absent were not treated with anticoagulants and were followed up for 3 months. Of the 393 patients, the prevalence of PE was 28 %. V/Q SPECT was positive for PE in 110 patients (28 %) and negative in 283 patients (72 %). Of the 110 patients with a positive V/Q SPECT, 78 (71 %) had at least one additional imaging test (computed tomography pulmonary angiography or ultrasound) and the diagnosis of PE was eventually excluded in one patient. Of the 283 patients with a negative V/Q SPECT, 74 (26 %) patients had another test. The diagnosis of PE was finally retained in one patient and excluded in 282 patients. The 3-month thromboembolic risk in the patients not treated with anticoagulants was 1/262: 0.38 % (95 % confidence interval 0.07-2.13). A diagnostic management including V/Q SPECT interpreted with a diagnostic cut-off of ''one segmental or two subsegmental mismatches'' appears safe to exclude PE. (orig.)

  16. Evaluation of isovolemic hemodilution therapy in acute ischemic stroke by means of single photon emission CT

    International Nuclear Information System (INIS)

    Thirteen patients who were started on isovolemic hemodilution within forty-eight hours of the onset of an ischemic stroke were studied. All patients had vascular lesions of the internal carotid artery or the middle cerebral artery. We measured the cerebral blood flow (CBF) using single photon emission CT and 133-Xe inhalation before and after the hemodilution. Neurological assessment was made according to the scoring system set up in the protocol of the Scandinavian Stroke Study Group. Scoring was done on admission, on the third day, and on the seventh day. According to the results, the patients were divided into two groups according to whether the treatment was judged as being either effective or ineffective. Of the thirteen patients, six were considered to have been effectively treated, while the remaining seven showed no significant improvement. Age, sex, the length of time from the onset to the start of hemodilution, changes in the hematocrit, and the volume of venesection were observed to be insignificant in both the effectively and ineffectively treated groups. In the effectively treated group, the mean CBF in both the affected and nonaffected hemispheres increased significantly, from 47.2±10.5 and 56.3±6.8 ml/100 g/minute to 58.5±10.8 and 62.5±9.0 ml/100 g/minute respectively. In the ineffectively treated group, however, only the mean CBF in the nonaffected hemisphere increased significantly - from 55.1±7.2 to 59.9±6.5 ml/100 g/minute. Based on these results, we conclude that a further evaluation of isovolemic hemodilution using refined patient selection is indicated. (author)

  17. Single-photon emission computed tomography/computed tomography in abdominal diseases.

    Science.gov (United States)

    Schillaci, Orazio; Filippi, Luca; Danieli, Roberta; Simonetti, Giovanni

    2007-01-01

    Single-photon emission computed tomography (SPECT) studies of the abdominal region are established in conventional nuclear medicine because of their easy and large availability, even in the most peripheral hospitals. It is well known that SPECT imaging demonstrates function, rather than anatomy. It is useful in the diagnosis of various disorders because of its ability to detect changes caused by disease before identifiable anatomic correlates and clinical manifestations exist. However, SPECT data frequently need anatomic landmarks to precisely depict the site of a focus of abnormal tracer uptake and the structures containing normal activity; the fusion with morphological studies can furnish an anatomical map to scintigraphic findings. In the past, software-based fusion of independently performed SPECT and CT or magnetic resonance images have been demonstrated to be time consuming and not useful for routine clinical employment. The recent development of dual-modality integrated imaging systems, which provide SPECT and CT images in the same scanning session, with the acquired images co-registered by means of the hardware, has created a new scenario. The first data have been mainly reported in oncology patients and indicate that SPECT/CT is very useful because it is able to provide further information of clinical value in several cases. In SPECT studies of abdominal diseases, hybrid SPECT/CT can play a role in the differential diagnosis of hepatic hemangiomas located near vascular structures, in precisely detecting and localizing active splenic tissue caused by splenosis in splenectomy patients, in providing important information for therapy optimization in patients submitted to hepatic arterial perfusion scintigraphy, in accurately identifying the involved bowel segments in patients with inflammatory bowel diseases, and in correctly localizing the bleeding sites in patients with gastrointestinal bleeding. PMID:17161039

  18. Phantom evaluation of simultaneous thallium-201/technetium-99m acquisition in single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cao Zongjian [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Chen, C.C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Maunoury, C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Holder, L.E. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Abraham, T.C. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States); Tehan, A. [Department of Diagnostic Radiology, University of Maryland Medical Center, Baltimore, MD (United States)

    1996-11-01

    This study investigated downscatter effects in cardiac single-photon emission tomographic studies with simultaneous thallium-201/technetium-99m acquisition, and evaluated a previously proposed subtraction technique for downscatter compensation. Ten studies were carried out with different defect sizes and locations and varying activity distributions using four energy windows: 70{+-}10% keV, 140{+-}10% keV, 100{+-}10% KeV, and 103{+-}16% keV. The subtraction technique used the 100- or 103-keV data to remove scattered {sup 99m}Tc counts from the 70-keV data. The size and contrast of infarcts in the dual-isotope 70-keV image were artificially decreased compared to those in the 140-keV image, caused by scattered {sup 99m}Tc counts that were comparable to the primary {sup 201}Tl counts in the 70-keV window. The subtraction technique produced larger defects and more heterogeneous activity in the myocardial wall in dual-isotope 70-keV images compared to the corresponding {sup 201}Tl-only images. These artifacts were caused by the markedly different spatial distributions of scattered {sup 99m}Tc counts in the 100-keV (or 103-keV) window as compared with the 70-keV window. It is concluded that scattered {sup 99m}Tc photons may cause overestimation of ischemia and myocardial viability in simultaneous dual-isotope patient studies. The proposed subtraction technique was inaccurate and produced image artifacts. Adequate downscatter compensation methods must be developed before applying simultaneous {sup 201}Tl/{sup 99m}Tc acquisition in clinical practice. (orig.). With 6 figs., 3 tabs.

  19. Proton magnetic resonance spectroscopy and single photon emission CT in patients with olivopontocerebellar atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Naomi [Yamaguchi Univ., Ube (Japan). School of Medicine

    1998-04-01

    Using proton magnetic resonance spectroscopy ({sup 1}H-MRS) and single photon emission CT (SPECT), the cerebellum of patients with olivopontocerebellar atrophy (OPCA) and of age-matched control subjects was studied. A spectrum was collected from a 27 cm{sup 3} (3 x 3 x 3 cm) voxel in the cerebellum containing white and gray matters in order to measure the distribution and relative signal intensities of N-acetylaspartate (NAA), creatine (Cre) and choline (Cho). In the cerebellum of the patients with OPCA, mean NAA/Cre ratios for OPCA patients were significantly decreased compared with normal control subjects (OPCA, 1.01{+-}0.247; controls, 1.526{+-}0.144: p<0.001). Mean NAA/Cho ratios for OPCA patients were slightly decreased (OPCA, 1.285{+-}0.228; controls 1.702{+-}0.469: p<0.06). Cho/Cre ratios valued in the cerebellum of OPCA patients were not significantly different from those in normal controls (OPCA, 0.793{+-}0.186; controls, 0.946{+-}0.219). The ratio of RI count in the cerebellum to that in the occipital lobe was significantly decreased in OPCA patients (OPCA, 0.947{+-}0.096; controls, 1.06{+-}0.063: p<0.01). Cerebellar signs were assessed including gait ataxia, limb ataxia, dysarthria, saccadic pursuit, and nystagmus separately or in combination. In patients with more severe ataxic gait and dysarthria, MRS revealed slightly lowered NAA/Cre ratio. There was no significant correlation between NAA/Cre ratio and severity of other clinical signs. The MRS and SPECT findings give a confirmative evidence of hypofunction in cerebellum of patients with OPCA. (author)

  20. Interictal "patchy" regional cerebral blood flow patterns in migraine patients. A single photon emission computerized tomographic study

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, J; Iversen, Helle Klingenberg;

    1994-01-01

    In 92 migraine patients and 44 healthy control subjects we recorded regional cerebral blood flow (rCBF) with single photon emission computerized tomography and (133) Xe inhalation or with i.v. (99m) Tc-HMPAO. Migraine patients were studied interictally. A quantitated analysis of right-left asymme......In 92 migraine patients and 44 healthy control subjects we recorded regional cerebral blood flow (rCBF) with single photon emission computerized tomography and (133) Xe inhalation or with i.v. (99m) Tc-HMPAO. Migraine patients were studied interictally. A quantitated analysis of right...... patients having attacks with aura and from 19% of patients without aura attacks was scored as containing abnormal right-left asymmetries by the visual analysis. Images from healthy controls were all scored to be normal. In 37% of the images (all from patients) there was lack of consensus among observers (κ...

  1. Influence of the excitation pulse width on the purity of single-photon emission from light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hargart, Fabian; Kessler, Christian; Reischle, Matthias; Schulz, Wolfgang-Michael; Eichfelder, Marcus; Rossbach, Robert; Jetter, Michael; Michler, Peter [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, Allmandring 3, 70569 Stuttgart (Germany); Gartner, Paul; Florian, Matthias; Gies, Christopher; Jahnke, Frank [Institut fuer Theoretische Physik, Universitaet Bremen, Postfach 330 440, 28334 Bremen (Germany)

    2012-07-01

    For many applications in quantum information single-photons on demand are desirable. Electrically driven semiconductor quantum dots (QDs) are a promising solution due to their tailorable emission energy and the integration in well-known semiconductor devices. Pulsed lasers afford an almost instantaneous excitation of the QDs compared to their decay time. In contrast, electrical pulse generators feature pulse-widths only down to several 10 ps. Therefore we determine the influence of the excitation pulses on the purity of single-photon emission from InP/GaInP quantum dots. For rising widths we observe an increasing g{sup (2)}(0)-value, which we relate to an increasing probability of further excitations during one single cycle. Using autocorrelation measurements with high temporal resolution we can distinguish the background contribution from re-excitation processes on the non-vanishing g{sup (2)}(0)-value. Theoretical investigations are in a good agreement with the experimental results.

  2. Measurements of wavelength-dependent double photoelectron emission from single photons in VUV-sensitive photomultiplier tubes

    CERN Document Server

    Faham, C H; Currie, A; Dobi, A; Sorensen, P; Gaitskell, R J

    2015-01-01

    Measurements of double photoelectron emission (DPE) probabilities as a function of wavelength are reported for Hamamatsu R8778, R8520, and R11410 VUV-sensitive photomultiplier tubes (PMTs). In DPE, a single photon strikes the PMT photocathode and produces two photoelectrons instead of a single one. It was found that the fraction of detected photons that result in DPE emission is a function of the incident photon wavelength, and manifests itself below $\\sim$250 nm. For the xenon scintillation wavelength of 175 nm, a DPE probability of 18--24\\% was measured depending on the tube and measurement method. This wavelength-dependent single photon response has implications for the energy calibration and photon counting of current and future liquid xenon detectors such as LUX, LZ, XENON100/1T, Panda-X and XMASS.

  3. Combined single photon emission computerised tomography and conventional computerised tomography (SPECT/CT) in patellofemoral disorders: a clinical review

    OpenAIRE

    Hirschmann, Michael T.; Davda, Kinner; Iranpour, Farhad; Rasch, Helmut; Friederich, Niklaus F.

    2010-01-01

    Patellofemoral disorders are common conditions seen in a knee clinic but can present a great diagnostic challenge to the orthopaedic surgeon. Combined single photon emission computerised tomography with conventional computer tomography (SPECT/CT) provides the clinician with precise anatomical and physiological information of the patellofemoral joint. We present a clinical review that highlights the value of SPECT/CT in patients with patellofemoral disorders, where other modalities such as rad...

  4. Sentinel Lymph Node Detection by 3D Freehand Single-Photon Emission Computed Tomography in Early Stage Breast Cancer

    OpenAIRE

    Salih Sinan Gültekin; Ahmet Oğuz Hasdemir; Emine Öztürk

    2016-01-01

    We herein present our first experience obtained by 3D freehand single-photon emission computed tomography (SPECT) (F-SPECT) guidance for sentinel lymph node detection (SLND) in two patients with early stage breast cancer. F-SPECT guidance was carried out using one-day protocol in one case and by the two-day protocol in the other one. SLND was performed successfully in both patients. Histopathologic evaluation showed that the excised nodes were tumor negative. Thus, patients underw...

  5. Impact of ventilation/perfusion single-photon emission computed tomography on treatment duration of pulmonary embolism

    OpenAIRE

    Begic, Amela; Opanković, Emina; Cukić, Vesna; Rustempašić, Medzida; Bašić, Amila; Miniati, Massimo; Jögi, Jonas; Bajc, Marika

    2014-01-01

    Purpose The aim of the study was to establish whether the duration of anticoagulant (AC) therapy can be tailored, on an objective basis, by using ventilation/perfusion single-photon emission computed tomography (V/P SPECT) and to assess the extent of residual perfusion defects over time. In particular, we addressed the following: (a) is the extent of perfusion recovery at 3 months of initial pulmonary embolism (PE) diagnosis a satisfactory criterion for deciding the duration of oral AC? (b) I...

  6. Single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I]-iodoamphetamine in epilepsy

    International Nuclear Information System (INIS)

    In order to delineate a seizure focus and to clarify the cerebral blood flow in epilepsy, single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) was performed on 38 patients (14 symptomatic and 24 idiopathic epilepsy including one patient who was studied on both ictal and interictal phase), and the findings of 123I-IMP SPECT were compared with those of X-ray computed tomography (X-CT) and electroencephalogram (EEG). Abnormality of accumulation of 123I-IMP was observed in 13 out of the 14 symptomatic, 16 out of the 23 interictal idiopathic and all of the 2 ictal idiopathic epileptic patients. On the other hand, in idiopathic epilepsy the detectability (2/24) of focal abnormality in the brain by X-CT was found to be lower than that of 123I-IMP SPECT. In 6 out of the 10 interictal idiopathic epileptic patients, showing normal EEG, the abnormality of accumulation of the radionuclide was observed on 123I-IMP SPECT. Among these 6 idiopathic epileptic patients, however, the pattern of the accumulation of the radionuclide was variable; some patients showed the increased accumulation in the seizure focus, others did the decreased perfusion. Furthermore, some cases showed the decreased perfusion in the different areas from the lesions of epileptic discharge on EEG. Although the mechanism of accumulation of 123I-IMP in the seizure foci is not completely clear, 123I-IMP SPECT was thought to be useful in the detection of focal abnormality in brain in epilepsy. (author)

  7. Characterization of [[sup 123]I]IDAM as a novel single-photon emission tomography tracer for serotonin transporters

    Energy Technology Data Exchange (ETDEWEB)

    Kung Mei-Ping; Hou, C.; Oya Shunichi; Mu Mu; Acton, P.D. (Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States)); Kung, H.F. (Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States) Department of Pharmacology, University of Pennsylvania, Philadelphia (United States))

    1999-08-01

    Development of selective serotonin transporter (SERT) tracers for single-photon emission tomography (SPET) is important for studying the underlying pharmacology and interaction of specific serotonin reuptake site inhibitors, commonly used antidepressants, at the SERT sites in the human brain. In search of a new tracer for imaging SERT, IDAM (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol) was developed. In vitro characterization of IDAM was carried out with binding studies in cell lines and rat tissue homogenates. In vivo binding of [[sup 125]I]IDAM was evaluated in rats by comparing the uptakes in different brain regions through tissue dissections and ex vivo autoradiography. In vitro binding study showed that IDAM displayed an excellent affinity to SERT sites (K[sub i]=0.097 nM, using membrane preparations of LLC-PK[sub 1] cells expressing the specific transporter) and showed more than 1000-fold of selectivity for SERT over norepinehrine and dopamine (expressed in the same LLC-PK[sub 1] cells). Scatchard analysis of [[sup 125]I]IDAM binding to frontal cortical membrane homogenates prepared from control or p-chloroamphetamine (PCA)-treated rats was evaluated. As expected, the control membranes showed a K[sub d] value of 0.25 nM[+-]0.05 nM and a B[sub max] value of 272[+-]30 fmol/ mg protein, while the PCA-lesioned membranes displayed a similar K[sub d], but with a reduced B[sub max] (20[+-]7 fmol/ mg protein). Biodistribution of [[sup 125]I]IDAM (partition coefficient =473; 1-octanol/buffer) in the rat brain showed a high initial uptake (2.44%dose at 2 min after i.v. injection) with the specific binding peaked at 60 min postinjection (hypothalamus-cerebellum/cerebellum =1.75). Ex vivo autoradiographs of rat brain sections (60 min after i.v. injection of [[sup 125]I]IDAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus

  8. Characterization of [{sup 123}I]IDAM as a novel single-photon emission tomography tracer for serotonin transporters

    Energy Technology Data Exchange (ETDEWEB)

    Kung Mei-Ping; Hou, C.; Oya Shunichi; Mu Mu; Acton, P.D. [Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States); Kung, H.F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States)]|[Department of Pharmacology, University of Pennsylvania, Philadelphia (United States)

    1999-08-01

    Development of selective serotonin transporter (SERT) tracers for single-photon emission tomography (SPET) is important for studying the underlying pharmacology and interaction of specific serotonin reuptake site inhibitors, commonly used antidepressants, at the SERT sites in the human brain. In search of a new tracer for imaging SERT, IDAM (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol) was developed. In vitro characterization of IDAM was carried out with binding studies in cell lines and rat tissue homogenates. In vivo binding of [{sup 125}I]IDAM was evaluated in rats by comparing the uptakes in different brain regions through tissue dissections and ex vivo autoradiography. In vitro binding study showed that IDAM displayed an excellent affinity to SERT sites (K{sub i}=0.097 nM, using membrane preparations of LLC-PK{sub 1} cells expressing the specific transporter) and showed more than 1000-fold of selectivity for SERT over norepinehrine and dopamine (expressed in the same LLC-PK{sub 1} cells). Scatchard analysis of [{sup 125}I]IDAM binding to frontal cortical membrane homogenates prepared from control or p-chloroamphetamine (PCA)-treated rats was evaluated. As expected, the control membranes showed a K{sub d} value of 0.25 nM{+-}0.05 nM and a B{sub max} value of 272{+-}30 fmol/ mg protein, while the PCA-lesioned membranes displayed a similar K{sub d}, but with a reduced B{sub max} (20{+-}7 fmol/ mg protein). Biodistribution of [{sup 125}I]IDAM (partition coefficient =473; 1-octanol/buffer) in the rat brain showed a high initial uptake (2.44%dose at 2 min after i.v. injection) with the specific binding peaked at 60 min postinjection (hypothalamus-cerebellum/cerebellum =1.75). Ex vivo autoradiographs of rat brain sections (60 min after i.v. injection of [{sup 125}I]IDAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus

  9. 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;

    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 by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon...... myocardial infarction, the AUC was 0.90 (95% CI: 0.87-0.94) and in patients without prior CAD the AUC for combined CTA-CTP was 0.93 (95% CI: 0.89-0.97). For the combination of a CTA stenosis ≥50% stenosis and a CTP perfusion deficit, the sensitivity, specificity, positive predictive, and negative predicative...

  10. Single-photon emission from a type-B InP/GaInP quantum dot

    Science.gov (United States)

    Beirne, G. J.; Michler, P.; Jetter, M.; Schweizer, H.

    2005-11-01

    Type-B InP/GaInP quantum dots are expected to exhibit a type-II electronic structure. Evidence for this is provided by the variation in decay time of the ensemble as a function of excitation power density. Photon correlation measurements were subsequently performed on a single type-B InP/GaInP quantum dot using a Hanbury-Brown and Twiss setup [Nature 178, 1447 (1956)]. Autocorrelation measurements were carried out under both continuous-wave and pulsed excitation conditions with single-photon emission observed in each case. The continuous-wave measurements display a pronounced antibunching dip at zero time delay while pulsed measurements enable the triggered generation of single photons on demand at a wavelength of approximately 750 nm.

  11. Detection of hypoxic brain tissue around the cerebral infarction by 99mTc-HL91 single photon emission computerized tomography%99mTc-HL91单光子计算机断层扫描对脑梗死灶周围乏氧组织的检测

    Institute of Scientific and Technical Information of China (English)

    刘耿熙; 杨友松

    2012-01-01

    Objective To investigate the detection of hypoxic brain tissue around the cerebral infarction (CI) by 99mTc-HL91 single photon emission computerized tomography (SPECT) . Methods Brain imanging detection were applied in 29 CI patients and 5 healthy controls by 99mTc-HL91 SPECT. The blood pressure, the levels of blood sugar and plasma fibrinogen (Fib) were checked in AC1 patients. Results SPECT.showed that 18 cases (62. 1% ) in ACI group were hypoxia imaging positive, while there were all negative in normal control group. Hypoxic imaging positive range in ACI patients with infarct lesion volume≤30 cm3 was negative correlated with the time of SPECT check (r= -0.624, P < 0.05); and positive correlated with the infarction lesion volume ( r =0.715, P< 0. 001 ). Conclusions 99mTc-HISl SPECT can show the hypoxic brain tissue around the focus of cerebral infarction. When ACI patients with infarct lesion volume ≤30 cm3, the earlier checking with SPECT, the higher positive rates of hypoxic imaging.%目的 探讨99mTc-HL91单光子计算机断层扫描(SPECT)对脑梗死灶周围乏氧组织的检测.方法 应用99mTc-HL91 SPECT对29例脑梗死患者和5名健康对照者进行脑显像检测,并对脑梗死患者进行血压、血糖和血浆纤维蛋白原(Fib)水平检查.结果 SPECT示脑梗死组脑组织乏氧显像阳性18例(62.1%),正常对照组均阴性.Spearman秩相关分析显示,梗死体积≤30 cm3的患者乏氧显像阳性范围与SPECT检测时间呈负相关(r(3)=-0.624,P<0.05),与脑梗死体积呈正相关(r(x)=0.715,P<0.001).结论 99mTc-HL91SPECT检测可显示脑梗死灶周围乏氧组织.梗死灶体积≤30 ml的脑梗死患者SPECT检测时间越早,则乏氧显像的阳性率越高.

  12. Coherent properties of single quantum dot transitions and single photon emission

    Energy Technology Data Exchange (ETDEWEB)

    Ester, Patrick

    2008-04-23

    of the first laser pulse. The relative phase of the QDs exciton can be controlled externally via the bias voltage. This effect is the basis for the observation of RAMSEY-fringes, which are presented in this work. The coherent manipulation of the p-shell is the basis for a novel excitation scheme for single photon emission. In this work it is shown that the first excited state can be coherently manipulated, similar to the ground state. (orig.)

  13. 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

  14. 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

  15. Quality of myocardial perfusion single-photon emission tomography imaging: multicentre evaluation with a cardiac phantom.

    Science.gov (United States)

    Heikkinen, J; Ahonen, A; Kuikka, J T; Rautio, P

    1999-10-01

    The aim of the study was to evaluate quality of myocardial perfusion single-photon emission tomography (SPET) imaging in Finnish hospitals. Nineteen nuclear medicine departments participated in the study. A myocardial phantom simulating clinical stress and rest conditions was filled with routinely used isotope solution (technetium-99m or thallium-201). The cardiac insert included three reversible defects (simulating ischaemia): 30x30x14 mm(3) septal (90% recovery at rest), 30x20x14 mm(3) posterobasal (full recovery) and 20x20x14 mm(3) lateral (full recovery). There were two fixed defects (simulating infarct): 30x20x14 mm(3) postero-apical and 10x10x6 mm(3) apical. The phantom was imaged and interpreted as a myocardial perfusion patient. Reconstruction, printout and reporting were performed according to the clinical routine of each centre. Three nuclear medicine specialists anonymously evaluated the quality of the image sets. The visual scores of the experts were ranked from 1 to 5. Additionally, points from 0 to 8 were given to research reports according to how well perfusion defects were detected. Quantitative points were calculated by comparing background-subtracted and -normalized counts from 12 regions of interest between stress and rest images. Results for technetium studies (12 departments) were better than those for thallium (7 departments). The average visual scores of the experts were 3.7+/-0. 9 for all image sets, 3.2+/-0.5 for thallium users and 3.9+/-0.6 for technetium users (P=0.003). Five laboratories received a low score which, according to the specialists, is barely sufficient for limited clinical use. Average points for the reports were 5.6+/-2.1, 4.9+/-1.5 and 6.5+/-1.7 (P=0.051), and for the quantitation 8.2+/-1. 0, 7.9+/-0.4 and 8.4+/-1.1 (P=0.185), respectively. Seven out of 22 interpreters did not detect the lateral 20x20x14 mm(3) defect; five of them used thallium. This study demonstrated the heterogeneity of myocardial perfusion SPET in

  16. Quality of myocardial perfusion single-photon emission tomography imaging: multicentre evaluation with a cardiac phantom

    Energy Technology Data Exchange (ETDEWEB)

    Heikkinen, J. [Dept. of Nuclear Medicine, Etela-Savo Hospital District, Mikkeli Central Hospital, Mikkeli (Finland); Ahonen, A. [Dept. of Nuclear Medicine, Oulu University Hospital (Finland); Kuikka, J.T. [Dept. of Clinical Physiology, Kuopio University Hospital and Niuvanniemi Hospital, Kuopio (Finland); Rautio, P. [Dept. of Clinical Physiology, North Karelia Central Hospital, Joensuu (Finland)

    1999-10-01

    The aim of the study was to evaluate quality of myocardial perfusion single-photon emission tomography (SPET) imaging in Finnish hospitals. Nineteen nuclear medicine departments participated in the study. A myocardial phantom simulating clinical stress and rest conditions was filled with routinely used isotope solution (technetium-99m or thallium-201). The cardiac insert included three reversible defects (simulating ischaemia): 30 x 30 x 14 mm{sup 3} septal (90% recovery at rest), 30 x 20 x 14 mm{sup 3} posterobasal (full recovery) and 20 x 20 x 14 mm{sup 3} lateral (full recovery). There were two fixed defects (simulating infarct): 30 x 20 x 14 mm{sup 3} postero-apical and 10 x 10 x 6 mm{sup 3} apical. The phantom was imaged and interpreted as a myocardial perfusion patient. Reconstruction, printout and reporting were performed according to the clinical routine of each centre. Three nuclear medicine specialists anonymously evaluated the quality of the image sets. The visual scores of the experts were ranked from 1 to 5. Additionally, points from 0 to 8 were given to research reports according to how well perfusion defects were detected. Quantitative points were calculated by comparing background-subtracted and -normalized counts from 12 regions of interest between stress and rest images. Results for technetium studies (12 departments) were better than those for thallium (7 departments). The average visual scores of the experts were 3.7{+-}0.9 for all image sets, 3.2{+-}0.5 for thallium users and 3.9{+-}0.6 for technetium users (P=0.003). Five laboratories received a low score which, according to the specialists, is barely sufficient for limited clinical use. Average points for the reports were 5.6{+-}2.1, 4.9{+-}1.5 and 6.5{+-}1.7 (P=0.051), and for the quantitation 8.2{+-}1.0, 7.9{+-}0.4 and 8.4{+-}1.1 (P=0.185), respectively. Seven out of 22 interpreters did not detect the lateral 20 x 20 x 14 mm{sup 3} defect; five of them used thallium. This study demonstrated

  17. Coherent properties of single quantum dot transitions and single photon emission

    International Nuclear Information System (INIS)

    of the first laser pulse. The relative phase of the QDs exciton can be controlled externally via the bias voltage. This effect is the basis for the observation of RAMSEY-fringes, which are presented in this work. The coherent manipulation of the p-shell is the basis for a novel excitation scheme for single photon emission. In this work it is shown that the first excited state can be coherently manipulated, similar to the ground state. (orig.)

  18. Bright Room-Temperature Single Photon Emission from Defects in Gallium Nitride

    CERN Document Server

    Berhane, Amanuel M; Bodrog, Zoltán; Fiedler, Saskia; Schröder, Tim; Triviño, Noelia Vico; Palacios, Tomás; Gali, Adam; Toth, Milos; Englund, Dirk; Aharonovich, Igor

    2016-01-01

    Single photon emitters play a central role in many photonic quantum technologies. A promising class of single photon emitters consists of atomic color centers in wide-bandgap crystals, such as diamond silicon carbide and hexagonal boron nitride. However, it is currently not possible to grow these materials as sub-micron thick films on low-refractive index substrates, which is necessary for mature photonic integrated circuit technologies. Hence, there is great interest in identifying quantum emitters in technologically mature semiconductors that are compatible with suitable heteroepitaxies. Here, we demonstrate robust single photon emitters based on defects in gallium nitride (GaN), the most established and well understood semiconductor that can emit light over the entire visible spectrum. We show that the emitters have excellent photophysical properties including a brightness in excess of 500x10^3 counts/s. We further show that the emitters can be found in a variety of GaN wafers, thus offering reliable and s...

  19. High-resolution single photon planar and spect imaging of brain and neck employing a system of two co-registered opposed gamma imaging heads

    Science.gov (United States)

    Majewski, Stanislaw; Proffitt, James

    2011-12-06

    A compact, mobile, dedicated SPECT brain imager that can be easily moved to the patient to provide in-situ imaging, especially when the patient cannot be moved to the Nuclear Medicine imaging center. As a result of the widespread availability of single photon labeled biomarkers, the SPECT brain imager can be used in many locations, including remote locations away from medical centers. The SPECT imager improves the detection of gamma emission from the patient's head and neck area with a large field of view. Two identical lightweight gamma imaging detector heads are mounted to a rotating gantry and precisely mechanically co-registered to each other at 180 degrees. A unique imaging algorithm combines the co-registered images from the detector heads and provides several SPECT tomographic reconstructions of the imaged object thereby improving the diagnostic quality especially in the case of imaging requiring higher spatial resolution and sensitivity at the same time.

  20. Assessment of cardiac single-photon emission computed tomography performance using a scanning linear observer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana [College of Optical Sciences, University of Arizona, Tucson, Arizona 85721 (United States); GE Healthcare, Haifa 39120 (Israel)

    2013-01-15

    Purpose: Single-photon emission computed tomography (SPECT) is widely used to detect myocardial ischemia and myocardial infarction. It is important to assess and compare different SPECT system designs in order to achieve the highest detectability of cardiac defects. Methods: Whitaker et al.'s study ['Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,' Opt. Express 16(11), 8150-8173 (2008)] on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than with reconstruction data. Thus, this observer model assesses the overall hardware performance independent of any reconstruction algorithm. In addition, the computation time of image quality studies is significantly reduced. In this study, three systems based on the design of the GE cadmium zinc telluride-based dedicated cardiac SPECT camera Discovery 530c were assessed. This design, which is officially named the Alcyone Technology: Discovery NM 530c, was commercialized in August, 2009. The three systems, GE27, GE19, and GE13, contain 27, 19, and 13 detectors, respectively. Clinically, a human heart can be virtually segmented into three coronary artery territories: the left-anterior descending artery, left-circumflex artery, and right coronary artery. One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can accurately predict in which territory the defect exists [http://www.asnc.org/media/PDFs/PPReporting081511.pdf, Guideline from American Society of Nuclear Cardiology]. A good estimation of the extent of the defect from the projection images is also very helpful for determining the seriousness of the myocardial ischemia. In this study, both the location and extent of defects were estimated by the SLO, and the system performance was assessed by

  1. Single-photon emission CT in the assessment of low back pain in young athletes

    International Nuclear Information System (INIS)

    Fifty-two teenage and young adult athletes (ages 12-24 years) with low back pain (LBP) underwent routine lumbar radiography and bone scintigraphy including planar and single-photon CT and SPECT imaging. This paper illustrates the significant limitations of routine radiography and the importance of SPECT bone scintigraphy in evaluating young athletes with LBP and suspected spondylolysis; the increased sensitivity and specificity of SPECT compared to planar scintigraphy in the diagnosis of spondylolysis; and the potential utility of follow-up SPECT studies in evaluating success of therapy in athletes with initially positive diagnostic indicators for spondylolysis or impending spondylolysis

  2. Incremental value of single photon emission tomography/computed tomography in 3-phase bone scintigraphy of an accessory navicular bone

    International Nuclear Information System (INIS)

    Accessory navicular bone is one of the supernumerary ossicles in the foot. Radiography is non diagnostic in symptomatic cases. Accessory navicular has been reported as a cause of foot pain and is usually associated with flat foot. Increased radio tracer uptake on bone scan is found to be more sensitive. We report a case highlighting the significance of single photon emission tomography/computed tomography in methylene diphosphonate bone scan in the evaluation of symptomatic accessory navicular bone where three phase bone scan is equivocal

  3. Sentinel Lymph Node Detection by 3D Freehand Single-Photon Emission Computed Tomography in Early Stage Breast Cancer

    Directory of Open Access Journals (Sweden)

    Salih Sinan Gültekin

    2016-06-01

    Full Text Available We herein present our first experience obtained by 3D freehand single-photon emission computed tomography (SPECT (F-SPECT guidance for sentinel lymph node detection (SLND in two patients with early stage breast cancer. F-SPECT guidance was carried out using one-day protocol in one case and by the two-day protocol in the other one. SLND was performed successfully in both patients. Histopathologic evaluation showed that the excised nodes were tumor negative. Thus, patients underwent breast-conserving surgery alone.

  4. Single photon emission and quantum ring-cavity coupling in InAs/GaAs quantum rings

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, E; Nowak, A K; Sanvitto, D; Meulen, H P van der; Calleja, J M [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); MartInez, L J; Prieto, I; Alija, A R; Granados, D; Taboada, A G; GarcIa, J M; Postigo, P A [Instituto de Microelectronica de Madrid, Centro Nacional de MicrotecnologIa, CSIC, Isaac Newton 8, PTM Tres Cantos, E-28760 Madrid (Spain); Sarkar, D, E-mail: eva.gallardo@uam.e [Department of Physics and Astronomy, University of Sheffield, S3 7RH (United Kingdom)

    2010-02-01

    Different InAs/GaAs quantum rings embedded in a photonic crystal microcavity are studied by quantum correlation measurements. Single photon emission, with g{sup (2)}(0) values around 0.3, is demonstrated for a quantum ring not coupled to the microcavity. Characteristic rise-times are found to be longer for excitons than for biexcitons, resulting in the time asymmetry of the exciton-biexciton cross-correlation. No antibunching is observed in another quantum ring weakly coupled to the microcavity.

  5. Detection of hepatic tumor by means of single photon emission computed tomography, Gray scale ultrasonography, and computed tomography

    International Nuclear Information System (INIS)

    We have studied the hepatic tumor detection by single photon emission computed tomography (SPECT) using rotatory chair and gamma camera. SPECT were taken by multiple section slice not only in transaxial view, but also in frontal and sagital. The results were superior in detectability to conventional liver scintiphoto (CLS). In cases of obstructive jaundice, ultrasonography (US) and/or computed axial tomography (CAT) should be taken before SPECT, because there are various probabilities of evaluation like as false positive by means of SPECT. Simultaneous interpretation of SPECT, US, and CAT was more helpful than independent interpretation

  6. Iodine-131 meta-iodobezylguanidine single photon emission computed tomography/computerized tomography in diagnosis of neuro-endocrine tumors

    International Nuclear Information System (INIS)

    Metaiodobenzyl guanidine (MIBG) is a derivative of guanethidine and acts as an analogue of nor-epinephrine and is widely used in the imaging of tumors of neuro-endocrine origin. Iodine-123 MIBG has ideal imaging characteristics but is expensive with limited availability. Iodine-131 MIBG is widely used in India and is cheap. Hybrid single photon emission computed tomography (SPECT)/computerized tomography (CT) allows for anatomico-functional imaging and is being tried in MIBG studies. However, the experience with I-131 MIBG is limited. We present a pictorial assay of I-131 MIBG SPECT/CT findings in various MIBG avid tumors

  7. Electrically driven single photon emission from a CdSe/ZnSSe/MgS semiconductor quantum dot

    International Nuclear Information System (INIS)

    We demonstrate electrically driven single photon emission from a CdSe/ZnSSe/MgS single quantum dot embedded in a resonant cavity light emitting diode. Patterned Pd/Au top contacts are used to inject the charge carriers locally. Single quantum dot electroluminescence is obtained at T = 4 K from nanoapertures lithographically defined in the top contacts. At low current densities, antibunching with a value of g(2)(0) = 0.16 is achieved. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Electrically driven single photon emission from a CdSe/ZnSSe/MgS semiconductor quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Quitsch, Wolf; Kuemmell, Tilmar; Bacher, Gerd [Werkstoffe der Elektrotechnik and CENIDE, Universitaet Duisburg-Essen, Bismarckstrasse 81, 47057 Duisburg (Germany); Gust, Arne; Kruse, Carsten; Hommel, Detlef [Institut fuer Festkoerperphysik, Universitaet Bremen, Otto-Hahn-Allee 1, 28334 Bremen (Germany)

    2014-07-15

    We demonstrate electrically driven single photon emission from a CdSe/ZnSSe/MgS single quantum dot embedded in a resonant cavity light emitting diode. Patterned Pd/Au top contacts are used to inject the charge carriers locally. Single quantum dot electroluminescence is obtained at T = 4 K from nanoapertures lithographically defined in the top contacts. At low current densities, antibunching with a value of g{sup (2)}(0) = 0.16 is achieved. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Synthesis of heterodimer radionuclide nanoparticles for magnetic resonance and single-photon emission computed tomography dual-modality imaging

    Science.gov (United States)

    Zhu, Jing; Zhang, Bin; Tian, Jian; Wang, Jiaqing; Chong, Yu; Wang, Xin; Deng, Yaoyao; Tang, Minghua; Li, Yonggang; Ge, Cuicui; Pan, Yue; Gu, Hongwei

    2015-02-01

    We report a facile synthesis of bifunctional Fe3O4-Ag125I heterodimers for use as dual-modality imaging agents in magnetic resonance (MR) and single-photon emission computed tomography (SPECT). We introduced 125I, which is a clinically used radioisotope, as a SPECT reporter, into Fe3O4-Ag heterodimer nanoparticles to provide a new type of bifunctional contrast agent for MRI and SPECT imaging.We report a facile synthesis of bifunctional Fe3O4-Ag125I heterodimers for use as dual-modality imaging agents in magnetic resonance (MR) and single-photon emission computed tomography (SPECT). We introduced 125I, which is a clinically used radioisotope, as a SPECT reporter, into Fe3O4-Ag heterodimer nanoparticles to provide a new type of bifunctional contrast agent for MRI and SPECT imaging. Electronic supplementary information (ESI) available: Details of general experimental procedures, TEM image. See DOI: 10.1039/c4nr07255c

  10. Single photon emission computed tomography (SPECT): Clinical routine diagnosis of cerebral malfunction

    International Nuclear Information System (INIS)

    Positron emission tomography is the gold standard for in vivo research in neurophysiology and pathology. The introduction of SPECT and the development of such tracers as 99mTc-HMPAYO (99mTc-d,l-hexamethylpropylenaminoxim) and, more recently, 123I-iomazenil and 123I-IBZM (123I-3-iodo-6-methoxybenzamide) allowed closer examination of the perfusion of the brain and neuroreceptor density mapping in more than the few institutions that can afford PET and the production of special tracers marked with a positron emitting nucleus. Nuclear medicine's future will be based on neuroreceptor density mapping, as further tracers will become commercially available and no other technique can probably show such low concentrations of the receptors. Probably MR techniques will be used for brain's perfusion measurement in future. For examination of a limited cerebral region xenon-enhanced CT is an alternative to perfusion measurements with HMPAO, or a very interesting supplement. Of the old techniques in nuclear medicine, examination of the liquor dynamics is still feasible and well supplemented by SPECT. (orig./MG)

  11. Single photon emission computed tomography (SPECT) findings using N-isopropyl-p-[{sup 123}I]iodoamphetamine ({sup 123}I-IMP) in schizophrenia and atypical psychosis

    Energy Technology Data Exchange (ETDEWEB)

    Suga, Hidemichi; Hayashi, Takuji; Mitsugi, Ohara [Aichi Medical Univ., Nagakute (Japan)

    1994-12-01

    As a basis for possible classification of schinzophrenic psychoses into schizophrenia and atypical psychosis, we studied the brain functional differences among 16 schizophrenic patients, 16 atypical psychosis patients and 16 healthy volunteers by single photon emission computed tomography (SPECT) using N-isopropyl-p-[{sup 123}I] iodoamphetamine. As a result, schizophrenics showed hypofrontality. On the other hand, atypical psychotics had no such hypofrontality but showed a reduced uptake rate in the right thalamic region. No influence of sex, duration of illness and medication was confirmed by the findings. The results suggest that schizophrenics might have some lesions in the frontal regions, whereas atypical psychotics might have no such lesions, but dysfunction in the right thalamic region. Consequently, the SPECT findings as least indicate possibly different etiologies for schizophrenia and atypical psychosis. (author).

  12. Iterative three-dimensional expectation maximization restoration of single photon emission computed tomography images: Application in striatal imaging

    International Nuclear Information System (INIS)

    Single photon emission computed tomography imaging suffers from poor spatial resolution and high statistical noise. Consequently, the contrast of small structures is reduced, the visual detection of defects is limited and precise quantification is difficult. To improve the contrast, it is possible to include the spatially variant point spread function of the detection system into the iterative reconstruction algorithm. This kind of method is well known to be effective, but time consuming. We have developed a faster method to account for the spatial resolution loss in three dimensions, based on a postreconstruction restoration method. The method uses two steps. First, a noncorrected iterative ordered subsets expectation maximization (OSEM) reconstruction is performed and, in the second step, a three-dimensional (3D) iterative maximum likelihood expectation maximization (ML-EM) a posteriori spatial restoration of the reconstructed volume is done. In this paper, we compare to the standard OSEM-3D method, in three studies (two in simulation and one from experimental data). In the two first studies, contrast, noise, and visual detection of defects are studied. In the third study, a quantitative analysis is performed from data obtained with an anthropomorphic striatal phantom filled with 123-I. From the simulations, we demonstrate that contrast as a function of noise and lesion detectability are very similar for both OSEM-3D and OSEM-R methods. In the experimental study, we obtained very similar values of activity-quantification ratios for different regions in the brain. The advantage of OSEM-R compared to OSEM-3D is a substantial gain of processing time. This gain depends on several factors. In a typical situation, for a 128x128 acquisition of 120 projections, OSEM-R is 13 or 25 times faster than OSEM-3D, depending on the calculation method used in the iterative restoration. In this paper, the OSEM-R method is tested with the approximation of depth independent

  13. Fundamental studies of myocardial defect size quantification using positron emission tomography and single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yoneyama, Tatsuya [Kanazawa Univ. (Japan). School of Medicine

    2001-04-01

    In Flurine-18 fluorodeoxyglucose ({sup 18}F-FDG) positron emission tomography (PET) acquisition, a transmission scan is usually performed before the PET tracer injection (cold transmission method), followed by a subsequent emission scan. However, this procedure is time consuming. An alternative approach, in which the transmission scan is performed after the emission scan (hot transmission method), would significantly reduce the time required for data acquisition. Recently, three-dimensional PET acquisition (3D PET) has become available. The counting sensitivity is much higher in 3D PET than in conventional two-dimensional PET (2D PET), resulting in a shorter acquisition time and reduced radiation exposure for the patient. On the other hand, {sup 18}F-FDG imaging using single photon emission computed tomography (SPECT), a more widely available method than PET, has emerged as an alternative to PET. The purpose of this study was to investigate the accuracy of measurement of myocardial defect sizes by these new techniques, using a chest phantom. Acquisitions were performed using an elliptical cylinder chest phantom. Plastic inserts, ranging in size from 2-60% of the myocardium (n=12), were used as simulated models of transmural myocardial infarction. Fluorine-18 was given into each part of the phantom. PET imaging with cold and hot transmission methods, 3D PET, and SPECT imaging were performed with different acquisition times and different radioisotope concentrations. All PET and SPECT data were analyzed using a semiquantitative polar map approach. Defect sizes were quantified using various cutoff thresholds, and were expressed as a percentage of the left ventricular myocardium. The PET and SPECT measurements were compared with the true defect sizes. Among the various cutoff levels tested, the mean absolute difference between the measured and true defect sizes was minimal at 50% of peak activity for both PET and SPECT. The PET measurements with the hot transmission

  14. Development and application of an automated analysis method for individual cerebral perfusion single photon emission tomography images

    CERN Document Server

    Cluckie, A J

    2001-01-01

    Neurological images may be analysed by performing voxel by voxel comparisons with a group of control subject images. An automated, 3D, voxel-based method has been developed for the analysis of individual single photon emission tomography (SPET) scans. Clusters of voxels are identified that represent regions of abnormal radiopharmaceutical uptake. Morphological operators are applied to reduce noise in the clusters, then quantitative estimates of the size and degree of the radiopharmaceutical uptake abnormalities are derived. Statistical inference has been performed using a Monte Carlo method that has not previously been applied to SPET scans, or for the analysis of individual images. This has been validated for group comparisons of SPET scans and for the analysis of an individual image using comparison with a group. Accurate statistical inference was obtained independent of experimental factors such as degrees of freedom, image smoothing and voxel significance level threshold. The analysis method has been eval...

  15. Few-view single photon emission computed tomography (SPECT) reconstruction based on a blurred piecewise constant object model

    CERN Document Server

    Wolf, Paul A; Schmidt, Taly G; Sidky, Emil Y

    2012-01-01

    A sparsity-exploiting algorithm intended for few-view Single Photon Emission Computed Tomography (SPECT) reconstruction is proposed and characterized. The algorithm models the object as piecewise constant subject to a blurring operation. To validate that the algorithm closely approximates the true object in the noiseless case, projection data were generated from an object assuming this model and using the system matrix. Monte Carlo simulations were performed to provide more realistic data of a phantom with varying smoothness across the field of view. Reconstructions were performed across a sweep of two primary design parameters. The results demonstrate that the algorithm recovers the object in a noiseless simulation case. While the algorithm assumes a specific blurring model, the results suggest that the algorithm may provide high reconstruction accuracy even when the object does not match the assumed blurring model. Generally, increased values of the blurring parameter and TV weighting parameters reduced noi...

  16. 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.

  17. Influence of pure dephasing on emission spectra from single photon sources

    DEFF Research Database (Denmark)

    Næsby Rasmussen, Andreas; Skovgård, Troels Suhr; Kristensen, Philip Trøst;

    2008-01-01

    We investigate the light-matter interaction of a quantum dot with the electromagnetic field in a lossy microcavity and calculate emission spectra for nonzero detuning and dephasing. It is found that dephasing shifts the intensity of the emission peaks for nonzero detuning. We investigate...... the characteristics of this intensity shifting effect and offer it as an explanation for the nonvanishing emission peaks at the cavity frequency found in recent experimental work....

  18. Measurement of regional cerebral blood flow with single photon emission computed tomography in patients with aphasia

    International Nuclear Information System (INIS)

    5 cases are demonstrated of patients with aphasia whose brain perfusion as measured regionally by SPECT using 133Xe was correlated to the lesions seen in the CT study. Perfusion reductions exceeded the CT visible lesions, such as, that in cortical lesions perfusion in the region of basal ganglia is diminished and vice versa. The findings are discussed in relation to recent work on brain perfusion and metabolism. (orig.)

  19. Engineered Quantum Dot Single Photon Sources

    CERN Document Server

    Buckley, Sonia; Vuckovic, Jelena

    2012-01-01

    Fast, high efficiency, and low error single photon sources are required for implementation of a number of quantum information processing applications. The fastest triggered single photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single photon emission, have made QD single photon sources more practical. Here we discuss the applications of single photon sources and their various requirements, before reviewing the progress made on a quantum dot platform in meeting these requirements.

  20. Purcell-enhanced single-photon emission from nitrogen-vacancy centers coupled to a tunable microcavity

    CERN Document Server

    Kaupp, Hanno; Mader, Matthias; Schlederer, Benedikt; Benedikter, Julia; Haeusser, Philip; Chang, Huan-Cheng; Fedder, Helmut; Hänsch, Theodor W; Hunger, David

    2016-01-01

    Optical microcavities are a powerful tool to enhance spontaneous emission of individual quantum emitters. However, the broad emission spectra encountered in the solid state at room temperature limit the influence of a cavity, and call for ultra-small mode volume. We demonstrate Purcell-enhanced single photon emission from nitrogen-vacancy (NV) centers in nanodiamonds coupled to a tunable fiber-based microcavity with a mode volume down to $1.0\\,\\lambda^{3}$. We record cavity-enhanced fluorescence images and study several single emitters with one cavity. The Purcell effect is evidenced by enhanced fluorescence collection, as well as tunable fluorescence lifetime modification, and we infer an effective Purcell factor of up to 2.0. With numerical simulations, we furthermore show that a novel regime for light confinement can be achieved, where a Fabry-Perot mode is combined with additional mode confinement by the nanocrystal itself. In this regime, effective Purcell factors of up to 11 for NV centers and 63 for si...

  1. Influence of respiratory gating, image filtering, and animal positioning on high-resolution electrocardiography-gated murine cardiac single-photon emission computed tomography

    NARCIS (Netherlands)

    Wu, Chao; Vaissier, Pieter E. B.; Vastenhouw, Brendan; de Jong, Johan R.; Slart, Riemer H. J. A.; Beekman, Freek J.

    2015-01-01

    Cardiac parameters obtained from single-photon emission computed tomographic (SPECT) images can be affected by respiratory motion, image filtering, and animal positioning. We investigated the influence of these factors on ultra-high-resolution murine myocardial perfusion SPECT. Five mice were inject

  2. Upper limit for the probability of single-photon emission following proton-induced double K-shell ionization of rubidium

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghazi, M.S.A.L.; Birchall, J.; McKee, J.S.C.

    1982-06-01

    The theoretical description of double ionization followed by the emission of a single photon is critically examined. Some numerical calculations based on existing models are carried out and the results obtained subjected to an experimental test in a suitably designed experiment. Some doubt is cast on the accuracy with which the existing theoretical models describe the process.

  3. Value of I-123-subtraction and single-photon emission computed tomography in addition to planar Tc-99m-MIBI scintigraphy before parathyroid surgery

    NARCIS (Netherlands)

    Jorna, Francisca H.; Jager, Pieter L.; Que, Tjin H.; Lemstra, Clara; Plukker, John T. M.

    2007-01-01

    Purpose. To find out if single-photon emission computed tomography (SPECT) and I-123-subtraction can enhance the findings of Tc-99-methoxyisobutylisonitrile (MIBI) scintigraphy for the preoperative localization of parathyroid (PT) tumors. Methods. Among the 111 consecutive patients who underwent pre

  4. In vivo measurement of haloperidol affinity to dopamine D2/D3 receptors by [123I]IBZM and single photon emission computed tomography

    DEFF Research Database (Denmark)

    Videbaek, C; Toska, K; Friberg, L;

    2001-01-01

    This study examines the feasibility of a steady-state bolus-integration method with the dopamine D2/D3 receptor single photon emission computer tomography (SPECT) tracer, [123I]IBZM, for determination of in vivo affinity of haloperidol. The nonspecific binding of [123I]IBZM was examined in the rat...

  5. Noninvasive diagnosis of coronary artery stenosis in women with limited exercise capacity: comparison of dobutamine stress echocardiography and 99mTc sestamibi single-photon emission CT

    NARCIS (Netherlands)

    A. Elhendy (Abdou); J.J. Bax (Jeroen); P.R. Nierop; M.L. Geleijnse (Marcel); M.M. Ibrahim; J.R.T.C. Roelandt (Jos); R.T. van Domburg (Ron)

    1998-01-01

    textabstractOBJECTIVES: To compare the accuracy of dobutamine stress echocardiography (DSE) and simultaneous 99mTc sestamibi (MIBI) single-photon emission CT (SPECT) imaging for the diagnosis of coronary artery stenosis in women. PATIENTS: Seventy women with limited exe

  6. Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode

    OpenAIRE

    Braun, T; V. Baumann; Iff, O.; Hoefling, S.; Schneider, C.; Kamp, M.

    2015-01-01

    We report on the enhancement of the spontaneous emission in the visible red spectral range from site-controlled InP/GaInP quantum dots by resonant coupling to Tamm-plasmon modes confined beneath gold disks in a hybrid metal/semiconductor structure. The enhancement of the emission intensity is confirmed by spatially resolved micro-photoluminescence area scans and temperature dependent measurements. Single photon emission from our coupled system is verified via second order autocorrelation meas...

  7. Absolute quantitation of iodine-123 epidepride kinetics using single-photon emission tomography: comparison with carbon-11 epidepride and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, P. [CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot; Hospital Garcia de Orta, Servico de Medicina Nuclear, Pragal, Almada (Portugal); Ribeiro, M.J. [CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot; Servico de Biofisica, IBILI, Faculdade de Medicina de Coimbra (Portugal); Bottlaender, M.; Loc' h, C.; Langer, O.; Strul, D.; Maziere, B.; Bendriem, B. [CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot; Hugonnard, P.; Grangeat, P. [CEA Centre d' Etudes Nucleaires de Grenoble, 38 (France). Lab. d' Electronique de Technologie et d' Instrumentation

    1999-12-01

    Epidepride labelled with iodine-123 is a suitable probe for the in vivo imaging of striatal and extrastriatal dopamine D{sub 2} receptors using single-photon emission tomography (SPET). Recently, this molecule has also been labelled with carbon-11. The goal of this work was to develop a method allowing the in vivo quantification of radioactivity uptake in baboon brain using SPET and to validate it using positron emission tomography (PET). SPET studies were performed in Papio anubis baboons using {sup 123}I-epidepride. Emission and transmission measurements were acquired on a dual-headed system with variable head angulation and low-energy ultra-high resolution (LEUHR) collimation. The imaging protocol consisted of one transmission measurement (24 min, heads at 90 ), obtained with two sliding line sources of gadolinium-153 prior to injection of 0.21-0.46 GBq of {sup 123}I-epidepride, and 12 emission measurements starting 5 min post injection. For scatter correction (SC) we used a dual-window method adapted to {sup 123}I. Collimator blurring correction (CBC) was done by deconvolution in Fourier space and attenuation correction (AT) was applied on a preliminary (CBC) filtered back-projection reconstruction using 12 iterations of a preconditioned, regularized minimal residual algorithm. For each reconstruction, a calibration factor was derived from a uniform cylinder filled with a {sup 123}I solution of a known radioactivity concentration. Calibration and baboon images were systematically built with the same reconstruction parameters. Uncorrected (UNC) and (AT), (SC+AT) and (SC+CBC+AT) corrected images were compared. PET acquisitions using 0.11-0.44 GBq of {sup 11}C-epidepride were performed on the same baboons and used as a reference. The radioactive concentrations expressed in percent of the injected dose per 100 ml (%ID/100 ml) obtained after (SC+CBC+AT) in SPET are in good agreement with those obtained with PET and {sup 11}C-epidepride. A method for the in vivo

  8. Absolute quantitation of iodine-123 epidepride kinetics using single-photon emission tomography: comparison with carbon-11 epidepride and positron emission tomography.

    Science.gov (United States)

    Almeida, P; Ribeiro, M J; Bottlaender, M; Loc'h, C; Langer, O; Strul, D; Hugonnard, P; Grangeat, P; Mazière, B; Bendriem, B

    1999-12-01

    Epidepride labelled with iodine-123 is a suitable probe for the in vivo imaging of striatal and extrastriatal dopamine D2 receptors using single-photon emission tomography (SPET). Recently, this molecule has also been labelled with carbon-11. The goal of this work was to develop a method allowing the in vivo quantification of radioactivity uptake in baboon brain using SPET and to validate it using positron emission tomography (PET). SPET studies were performed in Papio anubis baboons using 123I-epidepride. Emission and transmission measurements were acquired on a dual-headed system with variable head angulation and low-energy ultra-high resolution (LEUHR) collimation. The imaging protocol consisted of one transmission measurement (24 min, heads at 90 degrees), obtained with two sliding line sources of gadolinium-153 prior to injection of 0.21-0.46 GBq of 123I-epidepride, and 12 emission measurements starting 5 min post injection. For scatter correction (SC) we used a dual-window method adapted to 123I. Collimator blurring correction (CBC) was done by deconvolution in Fourier space and attenuation correction (AT) was applied on a preliminary (CBC) filtered back-projection reconstruction using 12 iterations of a preconditioned, regularized minimal residual algorithm. For each reconstruction, a calibration factor was derived from a uniform cylinder filled with a 123I solution of a known radioactivity concentration. Calibration and baboon images were systematically built with the same reconstruction parameters. Uncorrected (UNC) and (AT), (SC + AT) and (SC + CBC + AT) corrected images were compared. PET acquisitions using 0.11-0.44 GBq of 11C-epidepride were performed on the same baboons and used as a reference. The radioactive concentrations expressed in percent of the injected dose per 100 ml (% ID/100 ml) obtained after (SC + CBC + AT) in SPET are in good agreement with those obtained with PET and 11C-epidepride. A method for the in vivo absolute quantitation of 123

  9. Absolute quantitation of iodine-123 epidepride kinetics using single-photon emission tomography: comparison with carbon-11 epidepride and positron emission tomography

    International Nuclear Information System (INIS)

    Epidepride labelled with iodine-123 is a suitable probe for the in vivo imaging of striatal and extrastriatal dopamine D2 receptors using single-photon emission tomography (SPET). Recently, this molecule has also been labelled with carbon-11. The goal of this work was to develop a method allowing the in vivo quantification of radioactivity uptake in baboon brain using SPET and to validate it using positron emission tomography (PET). SPET studies were performed in Papio anubis baboons using 123I-epidepride. Emission and transmission measurements were acquired on a dual-headed system with variable head angulation and low-energy ultra-high resolution (LEUHR) collimation. The imaging protocol consisted of one transmission measurement (24 min, heads at 90 ), obtained with two sliding line sources of gadolinium-153 prior to injection of 0.21-0.46 GBq of 123I-epidepride, and 12 emission measurements starting 5 min post injection. For scatter correction (SC) we used a dual-window method adapted to 123I. Collimator blurring correction (CBC) was done by deconvolution in Fourier space and attenuation correction (AT) was applied on a preliminary (CBC) filtered back-projection reconstruction using 12 iterations of a preconditioned, regularized minimal residual algorithm. For each reconstruction, a calibration factor was derived from a uniform cylinder filled with a 123I solution of a known radioactivity concentration. Calibration and baboon images were systematically built with the same reconstruction parameters. Uncorrected (UNC) and (AT), (SC+AT) and (SC+CBC+AT) corrected images were compared. PET acquisitions using 0.11-0.44 GBq of 11C-epidepride were performed on the same baboons and used as a reference. The radioactive concentrations expressed in percent of the injected dose per 100 ml (%ID/100 ml) obtained after (SC+CBC+AT) in SPET are in good agreement with those obtained with PET and 11C-epidepride. A method for the in vivo absolute quantitation of 123I

  10. Dynamic single photon emission computed tomography using N-isopropyl-p-(/sup 123/I)iodoamphetamine for cerebrovascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Takashi; Kinoshita, Kazuo; Watanabe, Katsushi; Hoshi, Hiroaki; Jinnouchi, Seishi

    1988-03-01

    Continuous sequential single photon emission computed tomography (dynamic SPECT) with N-isopropyl-p-(/sup 123/I)iodoamphetamine (IMP) was perfomed in 17 patients with cerebrovascular diseases (three with transient ischemic attack, four with cerebral infarction, two with ruptured aneurysms, two with arteriovenous malformations (AVM), one with an unruptured giant aneurysm, and five with moyamoya disease). Dynamic SPECT scans were obtained with a circular-detector array emission CT instrument at a fixed level parallel to the orbitomeatal plane. The scans were taken over a 20-minute period, at 2-minute intervals, immediately after intravenous injection of IMP. Time courses of activity ratio of the affectednon-affected areas were calculated. Accumulation of IMP in ischemic areas was consistently suppressed to approximately 70 to 80% that in the non-affected areas. IMP accumulation in infarcted regions was less than 40 to 50% that in non-affected areas. In the regions of AVM and giant aneurysm, accumulation of IMP was rapid and relatively high, but its removal was prompt. Dynamic IMP SPECT appears useful in the assessment of cerebral perfusion and may have numerous applications in neurosurgery.

  11. The contribution of single photon emission computed tomography in the clinical assessment of Alzheimer type dementia; Apport de la tomographie d'emission monophonique cerebrale dans l'evaluation des demences de type Alzheimer

    Energy Technology Data Exchange (ETDEWEB)

    Boudousq, V.; Collombier, L.; Kotzki, P.O. [Centre Hospitalier Universitaire de Nimes, 30 (France)

    1999-12-01

    Interest of brain single-photon emission computed tomography to support clinical diagnosis of Alzheimer-type dementia is now established. Numerous studies have reported a decreased perfusion in the association cortex of the parietal lobe and the posterior temporal regions. In patients with mild cognitive complaints, the presence of focal hypoperfusion may increase substantially the probability of the disease. In addition, emission tomography emerges as a helpful tool in situation in which there is diagnostic doubt. In this case, the presence of temporo-parietal perfusion deficit associated with hippocampal atrophy on MRI or X-ray computed tomography contributes to diagnostic accuracy. However, some studies suggest that emission tomography may be useful for preclinical prediction of Alzheimer's disease and to predict cognitive decline. (author)

  12. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of {sup 99m}Tc-HMPAO single-photon emission tomography in clinical practice

    Energy Technology Data Exchange (ETDEWEB)

    Chang Chia-Cheng; Kuwana, Nobumasa; Noji, Masato; Tanabe, Yutaka; Koike, Y. [Department of Neurosurgery, Yokohama Minami Kyosai Hospital, Yokohama (Japan); Ikegami, Tadashi [Department of Radiology, Yokohama Minami Kyosai Hospital, Yokohama (Japan)

    1998-09-01

    The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography ({sup 99m}Tc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using {sup 99m}Tc-HMPAO SPET is reliable in clinical evaluations. (orig.) With 3 tabs., 10 refs.

  13. Single photon emission computed tomography (SPECT) findings using N-isopropyl-p-[[sup 123]I]iodoamphetamine ([sup 123]I-IMP) in schizophrenia and atypical psychosis

    Energy Technology Data Exchange (ETDEWEB)

    Suga, Hidemichi (Aichi Medical Univ., Nagakute (Japan))

    1993-05-01

    Sixteen schizophrenic patients, 16 atypical psychosis patients, and 16 healthy volunteers were subjected to single photon emission computed tomography (SPECT) of the brain using N-isopropyl-p-[[sup 123]I]iodoamphetamine ([sup 123]I-IMP). The basal ganglia region was in particular examined not only in transverse sections, but in coronal sections. Schizophrenics showed significantly decreased uptake rates in the bilateral frontal regions and increased uptakes in the bilateral basal ganglia. On the other hand, atypical psychotics had a reduced uptake rate only in the right thalamic region, compared to the controls. The increased uptake rates in the basal ganglia were associated with auditory hallucination, but gender difference, duration of illness and dose of neuroleptics had no influence on these SPECT findings. The results suggest that schizophrenics might have some lesions in the frontal area of the brain, whereas atypical psychotics might have no lesion in the frontal region but dysfunction in the right thalamic region. Subsequently, using only SPECT findings, all the cases were divided by cluster analysis into 4 groups and a residue group. Schizophrenics distributed mainly in the 2 groups that have lesion in the frontal regions. Atypical psychotics distributed principally in the other 2 groups that have alterations in the bilateral thalamic region. The present study suggests that schizophrenia and atypical psychosis might have different etiologies. (author).

  14. Monoamine oxidase B single-photon emission tomography with [123I]Ro 43-0463: imaging in volunteers and patients with temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Imaging of monoamine oxidase of subtype B (MAO B) is of interest in various neurological diseases. In the past non-invasive assessment of MAO B has only been possible with positron emission tomography (PET) ligands. Given the limited availability of PET, a single-photon emission tomography (SPET) ligand would be desirable. In this study SPET imaging with the new MAO B inhibitor [123I]Ro 43-0463 was performed in five volunteers and nine patients with temporal lobe epilepsy (TLE). In two volunteers a second study was performed 12 h following blockade with deprenyl. In the TLE patients the tracer was administered as bolus (n = 4) or as prolonged infusion (n = 5). The regional uptake pattern correlated well with the known distribution of MAO B. In the two blocking studies ligand uptake was substantially reduced compared with baseline. In the TLE patients increased uptake was found in the ipsilateral mesial temporal lobe and, surprisingly, in the ipsilateral putamen. This study indicates the potential of the new SPET ligand [123I]Ro 43-0463 to map MAO B concentration in the human brain. The new finding of increased MAO B in the putamen of TLE patients needs further studies to elucidate its exact pathophysiology. (orig.)

  15. Telecommunication Wavelength-Band Single-Photon Emission from Single Large InAs Quantum Dots Nucleated on Low-Density Seed Quantum Dots.

    Science.gov (United States)

    Chen, Ze-Sheng; Ma, Ben; Shang, Xiang-Jun; He, Yu; Zhang, Li-Chun; Ni, Hai-Qiao; Wang, Jin-Liang; Niu, Zhi-Chuan

    2016-12-01

    Single-photon emission in the telecommunication wavelength band is realized with self-assembled strain-coupled bilayer InAs quantum dots (QDs) embedded in a planar microcavity on GaAs substrate. Low-density large QDs in the upper layer active for ~1.3 μm emission are fabricated by precisely controlling the indium deposition amount and applying a gradient indium flux in both QD layers. Time-resolved photoluminescence (PL) intensity suggested that the radiative lifetime of their exciton emission is 1.5~1.6 ns. The second-order correlation function of g (2)(0) < 0.5 which demonstrates a pure single-photon emission. PMID:27576522

  16. Telecommunication Wavelength-Band Single-Photon Emission from Single Large InAs Quantum Dots Nucleated on Low-Density Seed Quantum Dots

    Science.gov (United States)

    Chen, Ze-Sheng; Ma, Ben; Shang, Xiang-Jun; He, Yu; Zhang, Li-Chun; Ni, Hai-Qiao; Wang, Jin-Liang; Niu, Zhi-Chuan

    2016-08-01

    Single-photon emission in the telecommunication wavelength band is realized with self-assembled strain-coupled bilayer InAs quantum dots (QDs) embedded in a planar microcavity on GaAs substrate. Low-density large QDs in the upper layer active for ~1.3 μm emission are fabricated by precisely controlling the indium deposition amount and applying a gradient indium flux in both QD layers. Time-resolved photoluminescence (PL) intensity suggested that the radiative lifetime of their exciton emission is 1.5~1.6 ns. The second-order correlation function of g 2(0) < 0.5 which demonstrates a pure single-photon emission.

  17. Dopamine transporter single-photon emission computerized tomography supports diagnosis of akinetic crisis of parkinsonism and of neuroleptic malignant syndrome.

    Science.gov (United States)

    Martino, G; Capasso, M; Nasuti, M; Bonanni, L; Onofrj, M; Thomas, A

    2015-04-01

    Akinetic crisis (AC) is akin to neuroleptic malignant syndrome (NMS) and is the most severe and possibly lethal complication of parkinsonism. Diagnosis is today based only on clinical assessments yet is often marred by concomitant precipitating factors. Our purpose is to evidence that AC and NMS can be reliably evidenced by FP/CIT single-photon emission computerized tomography (SPECT) performed during the crisis. Prospective cohort evaluation in 6 patients. In 5 patients, affected by Parkinson disease or Lewy body dementia, the crisis was categorized as AC. One was diagnosed as having NMS because of exposure to risperidone. In all FP/CIT, SPECT was performed in the acute phase. SPECT was repeated 3 to 6 months after the acute event in 5 patients. Visual assessments and semiquantitative evaluations of binding potentials (BPs) were used. To exclude the interference of emergency treatments, FP/CIT BP was also evaluated in 4 patients currently treated with apomorphine. During AC or NMS, BP values in caudate and putamen were reduced by 95% to 80%, to noise level with a nearly complete loss of striatum dopamine transporter-binding, corresponding to the "burst striatum" pattern. The follow-up re-evaluation in surviving patients showed a recovery of values to the range expected for Parkinsonisms of same disease duration. No binding effects of apomorphine were observed. By showing the outstanding binding reduction, presynaptic dopamine transporter ligand can provide instrumental evidence of AC in Parkinsonism and NMS.

  18. Assessment of endogenous dopamine release by methylphenidate challenge using iodine-123 iodobenzamide single-photon emission tomography

    International Nuclear Information System (INIS)

    This double-blind, placebo-controlled study assessed pharmacologically induced endogenous dopamine (DA) release in healthy male volunteers (n=12). Changes in endogenous DA release after injection of the psychostimulant drug methylphenidate were evaluated by single-photon emission tomography (SPET) and constant infusion of iodine-123 iodobenzamide ([123I[IBZM), a D2receptor radioligand that is sensitive to endogenous DA release. Methylphenidate induced displacement of striatal [ 123I[IBZM binding, resulting in a significantly decrease in the specific to non-specific [ 123I[IBZM uptake ratio (average: 8.6%) in comparison with placebo (average: -1.9%). Moreover, injection of methylphenidate induced significant behavioural responses on the following items: excitement, anxiety, tension, and mannerisms and posturing. The results of this study demonstrate the feasibility of using constant infusion of [ 123I[IBZM and SPET imaging to measure endogenous DA release after methylphenidate challenge and to investigate neurochemical aspects of behaviour. (orig.). With 2 figs., 1 tab

  19. Bronchopulmonary dysplasia: clinical grading in relation to ventilation/perfusion mismatch measured by single photon emission computed tomography.

    Science.gov (United States)

    Kjellberg, Malin; Björkman, Karin; Rohdin, Malin; Sanchez-Crespo, Alejandro; Jonsson, Baldvin

    2013-12-01

    Bronchopulmonary dysplasia (BPD) is a significant cause of morbidity in the preterm population. Clinical severity grading based on the need for supplemental oxygen and/or need for positive airway pressure at 36 weeks postmenstrual age does not yield reproducible predictive values for later pulmonary morbidity. Single photon emission computed tomography (SPECT) was used to measure the distribution of lung ventilation (V) and perfusion (Q) in 30 BPD preterm infants at a median age of 37 weeks postmenstrual age. The V and Q were traced with 5 MBq Technegas and Technetium-labeled albumin macro aggregates, respectively, and the V/Q match-mismatch was used to quantify the extent of lung function impairment. The latter was then compared with the clinical severity grading at 36 weeks, and time spent on mechanical ventilation, continuous positive airway pressure (CPAP) and supplemental oxygen. Of those with mild and moderate BPD 3/9 and 3/11 patients, respectively, showed significant V/Q mismatches. By contrast, 4/10 patients with severe BPD showed a satisfactory V/Q matching distribution. An unsatisfactory V/Q match was not correlated with time spent on supplemental oxygen or CPAP, but was significantly negatively correlated with time spent on mechanical ventilation. SPECT provides unique additional information about regional lung function. The results suggest that the current clinical severity grading can be improved and/or complemented with SPECT. PMID:23359534

  20. Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy

    International Nuclear Information System (INIS)

    The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed. 99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM. On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE. Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE. (author)

  1. Thallium-201 single photon emission computed tomography (SPECT) in patients with Duchenne's progressive muscular dystrophy. A histopathologic correlation study

    International Nuclear Information System (INIS)

    The pathomorphologic mechanism responsible for abnormal perfusion imaging during thallium-201 myocardial single photon emission computed tomography (201Tl-SPECT) in patients with Duchenne's progressive muscular dystrophy (DMD) was investigated. Hearts from 7 patients with DMD were evaluated histopathologically at autopsy and the results correlated with findings on initial and delayed resting 201Tl-SPECT images. The location of segments with perfusion defects correlated with the histopathologically abnormal segments in the hearts. Both the extent and degree of myocardial fibrosis were severe, especially in the posterolateral segment of the left ventricle. Severe transmural fibrosis and severe fatty infiltration were common in segments with perfusion defects. In areas of redistribution, the degree of fibrosis appeared to be greater than in areas of normal perfusion; and intermuscular edema was prominent. Thus, the degree and extent of perfusion defects detected by 201Tl-SPECT were compatible with the histopathology. The presence of the redistribution phenomenon may indicate ongoing fibrosis. Initial and delayed resting 201Tl-SPECT images can predict the site and progress of myocardial degeneration in patients with DMD. (author)

  2. Accuracy of ventricular volume and ejection fraction measured by gated Tl-201 perfusion single photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Moon, Dae Hyuk [University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2005-02-15

    Electrocardiogram-gated single photon emission computed tomography (SPECT) provides valuable information in the assessment of both myocardial perfusion and ventricular function. Tl-201 is a suboptimal isotope for gating. Tl-201 images are more blurred compared with Tc-99m tracers due to the increased amount of scattered photons and use of a smooth filter. The average myocardial count densities are approximately one-half those of conventional technetium tracers. However, Tl-201 is still widely used because of its well-established utility for assessing myocardial perfusion, viability and risk stratification. Gated SPECT with Tl-201 enables us to assess both post-stress and rest left ventricular volume and function. Previous studies with gated Tl-201 SPECT measurements of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) have shown high correlation with first-pass radionuclide angiography, gated blood pool scan, Tc-99m-MIBI gated SPECT, contrast ventriculography, echocardiography, and 3-dimensional magnetic resonance imaging. However, problems related to these studies include few agreement data of EDV and ESV, use of a reference method that is likely to have the same systemic errors (gated Tc-99 m-MIBI SPECT), and other technical factors related to the count density of gated SPECT. With optimization of gated imaging protocols and more validation studies, gated Tl-201 SPECT would be an accurate method to provide perfusion and function information in patients with coronary artery disease.

  3. Few-view single photon emission computed tomography (SPECT) reconstruction based on a blurred piecewise constant object model

    Science.gov (United States)

    Wolf, Paul A.; Jørgensen, Jakob S.; Schmidt, Taly G.; Sidky, Emil Y.

    2013-08-01

    A sparsity-exploiting algorithm intended for few-view single photon emission computed tomography (SPECT) reconstruction is proposed and characterized. The algorithm models the object as piecewise constant subject to a blurring operation. To validate that the algorithm closely approximates the true object in the noiseless case, projection data were generated from an object assuming this model and using the system matrix. Monte Carlo simulations were performed to provide more realistic data of a phantom with varying smoothness across the field of view and a cardiac phantom. Reconstructions were performed across a sweep of two primary design parameters. The results demonstrate that the algorithm recovers the object in a noiseless simulation case. While the algorithm assumes a specific blurring model, the results suggest that the algorithm may provide high reconstruction accuracy even when the object does not match the assumed blurring model. Generally, increased values of the blurring parameter and total variation weighting parameters reduced streaking artifacts, while decreasing spatial resolution. The proposed algorithm demonstrated higher correlation with respect to the true phantom compared to maximum-likelihood expectation maximization (MLEM) reconstructions. Images reconstructed with the proposed algorithm demonstrated reduced streaking artifacts when reconstructing from few views compared to MLEM. The proposed algorithm introduced patchy artifacts in some reconstructed images, depending on the noise level and the selected algorithm parameters. Overall, the results demonstrate preliminary feasibility of a sparsity-exploiting reconstruction algorithm which may be beneficial for few-view SPECT.

  4. Primary lymphedema of the lower limb: The clinical utility of single photon emission computed tomography/CT

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Mayo; Baumeister, Ruedinger G. H.; Frick, Andreas; Wallmichrath, Jens; Bartenstein, Peter; Rominger, Axel [Ludwig-Maximilians-University of Munich, Muenchen (Germany)

    2015-02-15

    The aim of this prospective study was to determine whether the additional use of the single photon emission computed tomography/CT (SPECT/CT) technique improves the diagnostic value of planar lymphoscintigraphy in patients presenting with primary lymph edema of the lower limb. For a defined period of three years (April 2011-April 2014) a total of 34 consecutive patients (28 females; age range, 27-83 years) presenting with swelling of the leg(s) suspicious of (uni- or bilateral, proximal or distal) primary lymphedema were prospectively examined by planar lymphoscintigraphy (lower limbs, n = 67) and the tomographic SPECT/CT technique (anatomical sides, n = 65). In comparison to pathological planar scintigraphic findings, the addition of SPECT/CT provided relevant additional information regarding the presence of dermal backflow (86%), the anatomical extent of lymphatic disorders (64%), the presence or absence of lymph nodes (46%), and the visualization of lymph vessels (4%). As an adjunct to planar lymphoscintigraphy, SPECT/CT specifies the anatomical correlation of lymphatic disorders and thus improves assessment of the extent of pathology due to the particular advantages of tomographic separation of overlapping sources. The interpretation of scintigraphic data benefits not only in baseline diagnosis, but also in physiotherapeutical and microsurgical treatments of primary lymphedema.

  5. Evaluation of dilated cardiomyopathy by /sup 201/Tl myocardial single photon emission computed tomography. Morphological and quantitative analysis

    Energy Technology Data Exchange (ETDEWEB)

    Futagami, Yasuo; Makino, Katsutoshi; Ichikawa, Takehiko

    1984-08-01

    To estimate dilated cardiomyopathy (DCM)morphologically and quantitatively, /sup 201/Tl myocardial single photon emission computed tomography (SPECT) was performed in 14 DCM and 5 normal cases. Using a rotating dual-gamma camera system, resting SPECT data were collected for 6 minutes. Quantitative analysis of clinical cases was based on phantom studies. Marked spherical left ventricular (LV) dilatation (14/14), localized-diffuse low uptake or defect (12/14), and right ventricular visualization (6/14) were characteristic features in DCM. Differentiation of DCM from ischemic heart disease by SPECT was possible through the feature indicating disproportionately large LV cavity to defect size or degree. Quantitative analysis When DCM was compared with normal control (n-5), following 3 features were impressive: DCM was significantly higher in LV myocardial /sup 201/Tl uptake ratio and LV volume than normal control; DCM was significantly lower in LV myocardial /sup 201/Tl uptake ratio of unit volume (1 ml) than normal control; DCM was significantly lower in mean myocardial count/mean lung count.ratio than normal control.

  6. Evaluation of myocardial infarction size with three-dimensional speckle tracking echocardiography: a comparison with single photon emission computed tomography.

    Science.gov (United States)

    Wang, Qiushuang; Zhang, Chunhong; Huang, Dangsheng; Zhang, Liwei; Yang, Feifei; An, Xiuzhi; Ouyang, Qiaohong; Zhang, Meiqing; Wang, Shuhua; Guo, Jiarui; Ji, Dongdong

    2015-12-01

    To assess whether global and regional myocardial strains from three-dimensional speckle tracking echocardiography (3D-STE) correlate with myocardial infarction size (MIS) detected by single photon emission computed tomography (SPECT). Fifty-seven patients with a history of ST-segment elevation myocardial infarction (MI) within 3-6 months were enrolled, alongside 24 healthy volunteers. Left ventricular (LV) global area strain, global longitudinal strain (GLS), global radial strain, global circumferential strain, left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) were measured and compared with the corresponding SPECT-detected MISs. Patients were sub-grouped into massive MIS group (MIS ≥ 12%) and small MIS group (MIS Myocardial strains of all the LV segments were compared with the corresponding MIS. Global myocardial strain parameters, LVEF and WMSI of the patients were significantly different from the control group (all P myocardial strain parameters were found between the massive and small MIS groups (all P myocardial strain parameters were observed between segments with and without transmural MIs (P myocardial strain parameters evaluated LV global MIS, 3D GLS had the highest diagnostic value. It also preliminarily gauged the degree of ischemia and necrosis of regional myocardial segments.

  7. The clinical meaning of gastric-wall hyperactivity observed on sestamibi cardiac single-photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cote, C.; Dumont, M. [Centre Hospitalier Universitaire de Quebec, Dept. of Nuclear Medicine, Quebec, Quebec (Canada)]. E-mail: christian.cote@chuq.qc.ca

    2004-06-01

    To evaluate prospectively the incidence and clinical meaning, if any, of gastric-wall hyperactivity observed on sestamibi cardiac single-photon emission computed tomography (SPECT). This phenomenon is completely different from the well-known intraluminal gastric reflux of sestamibi. A group of 819 patients who underwent sestamibi cardiac SPECT was studied from January 2000 to October 2000. Gastric-wall activity was graded qualitatively. Only patients with gastric-wall activity near or equivalent to their heart activity were considered for subsequent analysis. The medical records of patient candidates were reviewed, and their family physicians were asked to respond to a questionnaire by telephone when further information was needed. We identified 13 patients with significant gastric-wall hyperactivity, which was more intense on rest images. Our review of the clinical data shows that all these patients were suffering from dyspepsia and were taking gastric medication. These 13 cases were assigned to 3 groups: gastroesophageal reflux, chronic functional dyspepsia and nonspecific gastritis. Significant gastric-wall hyperactivity is an infrequent observation on sestamibi cardiac SPECT. Our results indicate that the presence of significant gastric-wall hyperactivity is associated with dyspepsia. It is important to realize that this gastric-wall hyperactivity by its proximity to the inferior myocardial wall could in some circumstances lead to either false-negative or false-positive findings, representing a diagnostic problem. Although infrequent, this situation could be avoided by proper quality control, including a systematic review of the raw cine data before reading the images. (author)

  8. Assessment of endogenous dopamine release by methylphenidate challenge using iodine-123 iodobenzamide single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Booij, J. [Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Korn, P. [Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Linszen, D.H. [Department of Psychiatry, Academic Medical Center, Tafelbergweg 25, 1105 BC Amsterdam (Netherlands); Royen, E.A. van [Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands)

    1997-06-10

    This double-blind, placebo-controlled study assessed pharmacologically induced endogenous dopamine (DA) release in healthy male volunteers (n=12). Changes in endogenous DA release after injection of the psychostimulant drug methylphenidate were evaluated by single-photon emission tomography (SPET) and constant infusion of iodine-123 iodobenzamide ([{sup 123}I]IBZM), a D{sub 2}receptor radioligand that is sensitive to endogenous DA release. Methylphenidate induced displacement of striatal [ {sup 123}I]IBZM binding, resulting in a significantly decrease in the specific to non-specific [ {sup 123}I]IBZM uptake ratio (average: 8.6%) in comparison with placebo (average: -1.9%). Moreover, injection of methylphenidate induced significant behavioural responses on the following items: excitement, anxiety, tension, and mannerisms and posturing. The results of this study demonstrate the feasibility of using constant infusion of [ {sup 123}I]IBZM and SPET imaging to measure endogenous DA release after methylphenidate challenge and to investigate neurochemical aspects of behaviour. (orig.). With 2 figs., 1 tab.

  9. 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.)

  10. 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.

  11. Degenerative dementia: nosological aspects and results of single photon emission computed tomography; Les demences degeneratives: aspects nosologiques et resultats de la tomographie d'emission monophotonique

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, B.; Habert, M.O. [Hopital Pitie-Salpetriere, 75 - Paris (France)

    1999-12-01

    Ten years ago, the diagnosis discussion of a dementia case for the old patient was limited to two pathologies: the Alzheimer illness and the Pick illness. During these last years, the frame of these primary degenerative dementia has fallen into pieces. The different diseases and the results got with single photon emission computed tomography are discussed. for example: fronto-temporal dementia, primary progressive aphasia, progressive apraxia, visio-spatial dysfunction, dementia at Lewy's bodies, or cortico-basal degeneration. (N.C.)

  12. Room Temperature Single-Photon Emission from Individual Perovskite Quantum Dots.

    Science.gov (United States)

    Park, Young-Shin; Guo, Shaojun; Makarov, Nikolay S; Klimov, Victor I

    2015-10-27

    Lead-halide-based perovskites have been the subject of numerous recent studies largely motivated by their exceptional performance in solar cells. Electronic and optical properties of these materials have been commonly controlled by varying the composition (e.g., the halide component) and/or crystal structure. Use of nanostructured forms of perovskites can provide additional means for tailoring their functionalities via effects of quantum confinement and wave function engineering. Furthermore, it may enable applications that explicitly rely on the quantum nature of electronic excitations. Here, we demonstrate that CsPbX3 quantum dots (X = I, Br) can serve as room-temperature sources of quantum light, as indicated by strong photon antibunching detected in single-dot photoluminescence measurements. We explain this observation by the presence of fast nonradiative Auger recombination, which renders multiexciton states virtually nonemissive and limits the fraction of photon coincidence events to ∼6% on average. We analyze limitations of these quantum dots associated with irreversible photodegradation and fluctuations ("blinking") of the photoluminescence intensity. On the basis of emission intensity-lifetime correlations, we assign the "blinking" behavior to random charging/discharging of the quantum dot driven by photoassisted ionization. This study suggests that perovskite quantum dots hold significant promise for applications such as quantum emitters; however, to realize this goal, one must resolve the problems of photochemical stability and photocharging. These problems are largely similar to those of more traditional quantum dots and, hopefully, can be successfully resolved using advanced methodologies developed over the years in the field of colloidal nanostructures. PMID:26312994

  13. Cortical perfusion response to an electrical stimulation of the auditory nerve in profoundly deaf patients: Study with technetium-99m hexamethylpropylene amine oxime single photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Le Scao, Y.; Robier, A.; Beuter, P. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Otorhinolaryngology); Baulieu, J.L.; Pourcelot, L. (Centre Hospitalier Universitaire, 37 - Tours (France). Dept. of Nuclear Medicine)

    1992-04-01

    Brain activation procedures associated with single photon emission tomography (SPET) have recently been developed in healthy controls and diseased patients in order to help in their diagnosis and treatment. We investigated the effects of a promontory test (PT) on the cerebral distribution of technetium-99m hexamethyl-propylene amine oxime ({sup 99m}Tc-HMPAO) in 7 profoundly deaf patients, 6 PT+ and PT-. The count variation in the temporal lobe was calculated on 6 coronal slices using the ratio (R{sub stimulation}-R{sub deprivation})/R{sub deprivation} where R=counts in the temporal lobe was observed in all patients and was higher in all patients with PT+ than in the patient with PT-. The problems of head positioning and resolution of the system were taken into account, and we considered that the maximal count increment was related to the auditory cortex response to the stimulus. Further clinical investigations with high-resolution systems have to be performed in order to validate this presurgery test in cochlear implant assessment. (orig.).

  14. Increased perfusion in motor areas after constraint-induced movement therapy in chronic stroke: a single-photon emission computerized tomography study.

    Science.gov (United States)

    Könönen, Mervi; Kuikka, Jyrki T; Husso-Saastamoinen, Minna; Vanninen, Esko; Vanninen, Ritva; Soimakallio, Seppo; Mervaala, Esa; Sivenius, Juhani; Pitkänen, Kauko; Tarkka, Ina M

    2005-12-01

    Hemiparesis is the most common deficit after cerebral stroke. Constraint-induced movement therapy (CIMT) is a new neurorehabilitation method that emphasizes task-relevant repetitive training for the stroke hand. Twelve chronic stroke patients were studied with single-photon emission computerized tomography at rest before and after the two-week CIMT period. Increased perfusion was found in motor control related areas. The specific areas with an increase in perfusion in the affected hemisphere were in the precentral gyrus, premotor cortex (Brodmann's area 6 (BA6)), frontal cortex, and superior frontal gyrus (BA10). In the nonaffected hemisphere, perfusion was increased in the superior frontal gyrus (BA6) and cingulate gyrus (BA31). In the cerebellum increased perfusion was seen bilaterally. The brain areas with increased perfusion receive and integrate the information from different sensory systems and plan the movement execution. Regional cerebral perfusion decreased in the lingual gyrus (BA18) in the affected hemisphere. In the nonaffected frontal cortex, two areas with decreased perfusion were found in the middle frontal gyrus (BA8/10). Also, the fusiform gyrus (BA20) and inferior temporal gyrus (BA37) in the nonaffected hemisphere showed decreased perfusion. Intensive movement therapy appears to change local cerebral perfusion in areas known to participate in movement planning and execution. These changes might be a sign of active reorganization processes after CIMT in the chronic state of stroke. PMID:15931162

  15. Rapid and efficient radiosynthesis of [{sup 123}I]I-PK11195, a single photon emission computed tomography tracer for peripheral benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Pimlott, Sally L. [Department of Clinical Physics, West of Scotland Radionuclide Dispensary, Western Infirmary, G11 6NT Glasgow (United Kingdom)], E-mail: s.pimlott@clinmed.gla.ac.uk; Stevenson, Louise [Department of Chemistry, WestCHEM, University of Glasgow, G12 8QQ Glasgow (United Kingdom); Wyper, David J. [Institute of Neurological Sciences, Southern General Hospital, G51 4TF Glasgow (United Kingdom); Sutherland, Andrew [Department of Chemistry, WestCHEM, University of Glasgow, G12 8QQ Glasgow (United Kingdom)

    2008-07-15

    Introduction: [{sup 123}I]I-PK11195 is a high-affinity single photon emission computed tomography radiotracer for peripheral benzodiazepine receptors that has previously been used to measure activated microglia and to assess neuroinflammation in the living human brain. This study investigates the radiosynthesis of [{sup 123}I]I-PK11195 in order to develop a rapid and efficient method that obtains [{sup 123}I]I-PK11195 with a high specific activity for in vivo animal and human imaging studies. Methods: The synthesis of [{sup 123}I]I-PK11195 was evaluated using a solid-state interhalogen exchange method and an electrophilic iododestannylation method, where bromine and trimethylstannyl derivatives were used as precursors, respectively. In the electrophilic iododestannylation method, the oxidants peracetic acid and chloramine-T were both investigated. Results: Electrophilic iododestannylation produced [{sup 123}I]I-PK11195 with a higher isolated radiochemical yield and a higher specific activity than achievable using the halogen exchange method investigated. Using chloramine-T as oxidant provided a rapid and efficient method of choice for the synthesis of [{sup 123}I]I-PK11195. Conclusions: [{sup 123}I]I-PK11195 has been successfully synthesized via a rapid and efficient electrophilic iododestannylation method, producing [{sup 123}I]I-PK11195 with a higher isolated radiochemical yield and a higher specific activity than previously achieved.

  16. Single photon emission tomography (SPET) imaging of dopamine D2 receptors in the course of dopamine replacement therapy in patients with nocturnal myoclonus syndrome (NMS)

    International Nuclear Information System (INIS)

    Single photon emission tomography (SPET) permits the in vivo measurements of regional cerebral radioactivity in the human brain following the administration of compounds labeled with photon-emitting isotopes. According to our SPET findings of a reduced binding of [123I]labeled (S)-2-hydroxy-3-iodo-6-methoxy-([1-ethyl-2-pyrrolidinyl]methyl) benzamide (IBZM) (a highly selective CNS D2 dopamine receptor ligand) to D2 dopamine receptors in striatal structures in untreated patients with nocturnal myoclonus syndrome (NMS) it seemed to be of interest to investigate whether there are changes in D2 receptor binding under dopamine replacement therapy or not. We studied the uptake and distribution of [123I]IBZM before and in the course of dopamine replacement therapy in four patients with severe insomnia caused by nocturnal myoclonus syndrome (NMS). We found an increase of the IBZM binding to D2 receptors in the course of treatment, which was associated with an improvement of sleep quality. Reasons for this are discussed. The [123I]IBZM SPET technique in conclusion offers an interesting tool for in vivo investigations of functional changes in the dopaminergic neurotransmitter system in longitudinal studies. (author)

  17. Use Of Clinical Decision Analysis In Predicting The Efficacy Of Newer Radiological Imaging Modalities: Radioscintigraphy Versus Single Photon Transverse Section Emission Computed Tomography

    Science.gov (United States)

    Prince, John R.

    1982-12-01

    Sensitivity, specificity, and predictive accuracy have been shown to be useful measures of the clinical efficacy of diagnostic tests and can be used to predict the potential improvement in diagnostic certitude resulting from the introduction of a competing technology. This communication demonstrates how the informal use of clinical decision analysis may guide health planners in the allocation of resources, purchasing decisions, and implementation of high technology. For didactic purposes the focus is on a comparison between conventional planar radioscintigraphy (RS) and single photon transverse section emission conputed tomography (SPECT). For example, positive predictive accuracy (PPA) for brain RS in a specialist hospital with a 50% disease prevalance is about 95%. SPECT should increase this predicted accuracy to 96%. In a primary care hospital with only a 15% disease prevalance the PPA is only 77% and SPECT may increase this accuracy to about 79%. Similar calculations based on published data show that marginal improvements are expected with SPECT in the liver. It is concluded that: a) The decision to purchase a high technology imaging modality such as SPECT for clinical purposes should be analyzed on an individual organ system and institutional basis. High technology may be justified in specialist hospitals but not necessarily in primary care hospitals. This is more dependent on disease prevalance than procedure volume; b) It is questionable whether SPECT imaging will be competitive with standard RS procedures. Research should concentrate on the development of different medical applications.

  18. Reliability of low-frequency auditory stimulation studies associated with technetium-99m hexamethylpropylene amine oxime single-photon emission tomography

    International Nuclear Information System (INIS)

    Development of auditory stimulation tests associated with single-photon emission tomography (SPET) shows evidence of variations in perfusion related to the stimuli. Three brain SPET examinations with technetium-99m hexamethylpropylene amine oxime were performed on eight right-handed adults with normal hearing, the first one without stimulation and the other two associated with a 500-Hz/30-dB stimulation of the right ear. Temporal regions of interest covering auditory areas, as well as parietal ones (internal control), were drawn on three successive coronal slices. A cortico-cerebellar index R was calculated, and the variation in activity was defined for each subject using the ratio Rpoststimulation - Rprestimulation/Rprestumulation. A significant increase in the temporal cortex count occurred in all subjects. This increase was bilateral, except for one subject in whom it was not significant on the right side. This result recurred during the second stimulation study. Overall the response of the left temporal cortex was stronger, although the asymmetry was not significant. The asymmetry repeated itself after each stimulation. The perfursion response is globally reliable in our study. We must ascertainhow sensitive this test is with regard to deaf adults and adults with normal hearing before extending its use to children. (orig.)

  19. Single-photon source characterization with infrared-sensitive superconducting single-photon detectors

    CERN Document Server

    Hadfield, R H; Nam, S W; Stevens, M J; Hadfield, Robert H.; Mirin, Richard P.; Nam, Sae Woo; Stevens, Martin J.

    2006-01-01

    Single-photon sources and detectors are key enabling technologies in quantum information processing. Nanowire-based superconducting single-photon detectors (SSPDs) offer single-photon detection from the visible well into the infrared with low dark counts, low jitter and short dead times. We report on the high fidelity characterization (via antibunching and spontaneous emission lifetime measurements) of a cavity-coupled single-photon source at 902 nm using a pair of SSPDs. The twin SSPD scheme reported here is well-suited to the characterization of single-photon sources at telecom wavelengths (1310 nm, 1550 nm).

  20. Cerebral amobarbital sodium distribution during Wada testing: utility of digital subtraction angiography and single-photon emission tomography

    International Nuclear Information System (INIS)

    We aimed to determine if the cerebral distribution of anesthetic during Wada testing is reflected by findings on digital subtraction angiography (DSA) and single-photon emission computed tomography (SPECT) and if the findings on these studies are relevant to the outcome of the Wada test. We carried out selective internal carotid artery (ICA) DSA on 29 patients underwent studies prior to a Wada test. In patients without angiographic cross-filling, amobarbital and a radiotracer were injected into each ICA, beginning with the epileptogenic side. In patients with cross-filling, the ICA ipsilateral to the epileptogenic focus was injected with amobarbital and radiotracer while other was injected with amobarbital alone. We analyzed the DSA studies for cross-filling and filling of the posterior cerebral arteries (PCA). We reviewed the SPECT for activity in the territories of the anterior, middle cerebral, and posterior cerebral arteries. We compared the results of both studies with the success or failure of the neuropsychological portion of the Wada test. In 20 patients without cross-filling, the results of DSA and SPECT were comparable: symmetrical hemisphere activity was seen. In nine patients with cross-filling, SPECT showed bilateral, almost symmetrical activity. Filling or nonfilling of the PCA correlated with activity (or lack of it) in the medial temporal and occipital regions in all patients. The Wada test was considered successful in all patients. The findings on SPECT did not alter interpretation of the Wada test and we suggest that it may not be needed in all patients undergoing Wada testing. (orig.)

  1. Cerebral amobarbital sodium distribution during Wada testing: utility of digital subtraction angiography and single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, M.; Mukherji, S.K.; McCartney, W.H. [Department of Radiology, University of North Carolina School of Medicine, Chapel Hill, NC (United States)

    2000-11-01

    We aimed to determine if the cerebral distribution of anesthetic during Wada testing is reflected by findings on digital subtraction angiography (DSA) and single-photon emission computed tomography (SPECT) and if the findings on these studies are relevant to the outcome of the Wada test. We carried out selective internal carotid artery (ICA) DSA on 29 patients underwent studies prior to a Wada test. In patients without angiographic cross-filling, amobarbital and a radiotracer were injected into each ICA, beginning with the epileptogenic side. In patients with cross-filling, the ICA ipsilateral to the epileptogenic focus was injected with amobarbital and radiotracer while other was injected with amobarbital alone. We analyzed the DSA studies for cross-filling and filling of the posterior cerebral arteries (PCA). We reviewed the SPECT for activity in the territories of the anterior, middle cerebral, and posterior cerebral arteries. We compared the results of both studies with the success or failure of the neuropsychological portion of the Wada test. In 20 patients without cross-filling, the results of DSA and SPECT were comparable: symmetrical hemisphere activity was seen. In nine patients with cross-filling, SPECT showed bilateral, almost symmetrical activity. Filling or nonfilling of the PCA correlated with activity (or lack of it) in the medial temporal and occipital regions in all patients. The Wada test was considered successful in all patients. The findings on SPECT did not alter interpretation of the Wada test and we suggest that it may not be needed in all patients undergoing Wada testing. (orig.)

  2. Property of electrocardiogram gated single photon emission tomography by sup 99m Tc-methoxy isobutyl isonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Kamon; Nishio, Yukari; Araki, Yasushi; Saito, Satoshi; Ozawa, Yukio; Yasugi, Tadao; Hagiwara, Kazuo; Kamata, Rikisaburo (Nihon Univ., Tokyo (Japan). School of Medicine)

    1992-06-01

    {sup 99m}Tc-methoxy isobutyl isonitrile (MIBI) is a new developed myocardial perfusion imaging agent. Because this compound has higher photon energy than thallium (Tl), electrocardiogram gated single photon emission tomography (SPECT): end-diastolic (ED) and end-systolic (ES) short axis (SA) images could be taken. To investigate property of gated MIBI SPECT, MIBI myocardial scintigraphy, Tl scintigraphy (TMS) and analysis of left ventricular wall motion were performed in 6 patients with myocardial infarction. Left ventricule was divided into 8 segments. Perfusion defect (PD) was scored: '0' (normal), '1' (hypo-perfusion), '2' (defect). Wall motion abnormality (WMA) was also scored: '0' (normo-kinesis), '1' (hypo-kinesis), '2' (a-, dys-kinesis). Severity and extent of PD and WMA were calculated. Severity of WMA was 3.0{+-}2.0 (M{+-}SD), severity of PD was 3.3{+-}1.7 in TMS, 3.7{+-}1.3 in no-gated MIBI, 5.0{+-}0.6 in ES-MIBI, 7.3{+-}2.0 in ED-MIBI. Extent of WMA was 2.3{+-}1.0. Extent of PD was 2.5{+-}1.3 in TMS, 3.0{+-}1.6 in no-gated MIBI, 3.5{+-}0.8 in ES-MIBI, 4.8{+-}1.0 in ED-MIBI. Compared with wall motion abnormality, severity and extent of PD in ED-MIBI was larger. From our data, it is concluded that perfusion defect in ED-MIBI was overestimated significantly. When we evaluate gated MIBI image, we must consider this property. (author).

  3. Regional cerebral blood flow in acute stage ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki (Akita Univ. (Japan). School of Medicine)

    1989-03-01

    During the period from February 1984 through June 1985, single photon emission computerized tomography (SPECT) with xenon-133 inhalation method has been performed for the measurement of regional cerebral blood flow (rCBF) during the first 48 hours of onset of cerebral infarction (n=71) and transient ischemic attack (n=21). X-ray CT (CT) and carotid arteriography were concurrently performed in all the patients. In repeated studies performed for 15 normal volunteers, rCBF measurement by SPECT was found reproducible. Mean values of rCBF for the right and left cerebral hemispheres were 60.3{plus minus}6.52 and 61.8{plus minus}6.91 ml/100 g/min, respectively. For cerebral infarction, ischemic foci corresponding to clinical symptoms were detected more frequently on SPECT than on CT (93% vs 63%). In all of the evaluable 35 patients with cerebral infarction, rCBF within the first 8 hours of onset was decreased: 31.0 ml/100 g/min for the internal carotid artery (ICA) occlusion and 36.0 ml/100 g/min for the middle cerebral artery (MCA) occlusion. Crossed cerebellar diaschisis was observed in 50% (9/18) for ICA occlusion and 37% (14/38) for MCA occlusion. For transient ischemic attack, there was no significant difference in the detection of ischemic foci between SPECT and CT (38% vs 43%). In detecting small foci especially in the deep regions such as the basal ganglia, SPECT was inferior to CT. Mean rCBF for transient ischemic attack tended to be lower than the normal rCBF (50.7 ml/100 g/min for the right cerebral hemisphere and 50.6 ml/100 g/min for the left cerebral hemisphere). SPECT may aid in predicting prognosis and chosing treatment strategy, as well as in determining cerebral hemodynamics. (N.K.).

  4. The Prognostic Role of Magnetic Resonance Imaging and Single-Photon Emission Computed Tomography in Viral Encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Misra, U.K.; Kalita, J.; Srivastav, A.; Pradhan, P.K. (Depts. of Neurology and Nuclear Medicine, Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India))

    2008-09-15

    Background: There is a paucity of studies evaluating the prognostic role of magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) changes in viral encephalitis. Purpose: To study MRI and SPECT changes in patients with viral encephalitis, and to correlate these changes with clinical findings and outcome. Material and Methods: During 1997-2006, 31 encephalitis patients (aged 2-60 years; nine females, 22 males) underwent both MRI and SPECT studies. Their demographic and clinical data and 6-month outcome were recorded. For the diagnosis of encephalitis, polymerase chain reaction (PCR) and IgM enzyme-linked immunosorbent assay (ELISA) were carried out. Cranial MRI was done on a 1.5 T scanner, and 99mTc ethylene cysteine dimer (ECD) SPECT using a gamma camera. Outcome was defined at 6 months as complete, partial, or poor recovery. Results: 19 patients had Japanese encephalitis (JE), one had herpes simplex encephalitis (HSE), and 11 had nonspecific encephalitis. Movement disorders were present in 21, parkinsonian features in 19, and dystonia in 16 patients. MRI was abnormal in 20 patients, and revealed thalamic involvement in 17, basal ganglia in eight, brainstem in 11, and cortical in two. SPECT revealed hypoperfusion in 22 patients, which was cortical in 11, thalamic in 10, basal ganglia in six, and midbrain in one. Cortical involvement was more frequently found by SPECT and brainstem involvement by MRI. Outcome of encephalitis did not differ in the different groups of encephalitis and MRI changes. Conclusion: MRI and SPECT show a spectrum of findings in encephalitis, but these do not correlate with 6-month outcome

  5. 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

  6. Polarization fine structure and enhanced single-photon emission of self-assembled lateral InGaAs quantum dot molecules embedded in a planar microcavity

    Science.gov (United States)

    Hermannstädter, C.; Witzany, M.; Beirne, G. J.; Schulz, W.-M.; Eichfelder, M.; Rossbach, R.; Jetter, M.; Michler, P.; Wang, L.; Rastelli, A.; Schmidt, O. G.

    2009-06-01

    Single lateral InGaAs quantum dot molecules have been embedded in a planar microcavity in order to increase the luminescence extraction efficiency. Using a combination of metal-organic vapor phase and molecular beam epitaxy samples could be produced that exhibit a 30 times enhanced single-photon emission rate. We also show that the single-photon emission is fully switchable between two different molecular excitonic recombination energies by applying a lateral electric field. Furthermore, the presence of a polarization fine structure splitting of the molecular neutral excitonic states is reported which leads to two polarization split classically correlated biexciton-exciton cascades. The fine structure splitting is found to be on the order of 10 μeV.

  7. Voxel-Based Correlation between Coregistered Single-Photon Emission Computed Tomography and Dynamic Susceptibility Contrast Magnetic Resonance Imaging in Subjects with Suspected Alzheimer Disease

    Energy Technology Data Exchange (ETDEWEB)

    Cavallin, L.; Axelsson, R.; Wahlund, L.O.; Oeksengard, A.R.; Svensson, L.; Juhlin, P.; Wiberg, M. Kristoffersen; Frank, A. [Division of Radiology, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden)

    2008-12-15

    Background: Current diagnosis of Alzheimer disease is made by clinical, neuropsychologic, and neuroimaging assessments. Neuroimaging techniques such as magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) could be valuable in the differential diagnosis of Alzheimer disease, as well as in assessing prognosis. Purpose: To compare SPECT and MRI in a cohort of patients examined for suspected dementia, including patients with no objective cognitive impairment (control group), mild cognitive impairment (MCI), and Alzheimer disease (AD). Material and Methods: 24 patients, eight with AD, 10 with MCI, and six controls, were investigated with SPECT using {sup 99m}Tc-hexamethylpropyleneamine oxime (HMPAO, Ceretec; GE Healthcare Ltd., Little Chalsont UK) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with a contrast-enhancing gadobutrol formula (Gadovist; Bayer Schering Pharma, Berlin, Germany). Voxel-based correlation between coregistered SPECT and DSC-MR images was calculated. Region-of-interest (ROI) analyses were then performed in 24 different brain areas using brain registration and analysis of SPECT studies (BRASS; Nuclear Diagnostics AB, Stockholm (SE)) on both SPECT and DSC-MRI. Results: Voxel-based correlation between coregistered SPECT and DSC-MR showed a high correlation, with a mean correlation coefficient of 0.94. ROI analyses of 24 regions showed significant differences between the control group and AD patients in 10 regions using SPECT and five regions in DSC-MR. Conclusion: SPECT remains superior to DSC-MRI in differentiating normal from pathological perfusion, and DSC-MRI could not replace SPECT in the diagnosis of patients with Alzheimer disease.

  8. Voxel-Based Correlation between Coregistered Single-Photon Emission Computed Tomography and Dynamic Susceptibility Contrast Magnetic Resonance Imaging in Subjects with Suspected Alzheimer Disease

    Energy Technology Data Exchange (ETDEWEB)

    Cavallin, L.; Axelsson, R.; Wahlund, L.O.; Oeksengard, A.R.; Svensson, L.; Juhlin, P.; Wiberg, M. Kristoffersen; Frank, A. (Division of Radiology, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden))

    2008-12-15

    Background: Current diagnosis of Alzheimer disease is made by clinical, neuropsychologic, and neuroimaging assessments. Neuroimaging techniques such as magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) could be valuable in the differential diagnosis of Alzheimer disease, as well as in assessing prognosis. Purpose: To compare SPECT and MRI in a cohort of patients examined for suspected dementia, including patients with no objective cognitive impairment (control group), mild cognitive impairment (MCI), and Alzheimer disease (AD). Material and Methods: 24 patients, eight with AD, 10 with MCI, and six controls, were investigated with SPECT using 99mTc-hexamethylpropyleneamine oxime (HMPAO, Ceretec; GE Healthcare Ltd., Little Chalsont UK) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with a contrast-enhancing gadobutrol formula (Gadovist; Bayer Schering Pharma, Berlin, Germany). Voxel-based correlation between coregistered SPECT and DSC-MR images was calculated. Region-of-interest (ROI) analyses were then performed in 24 different brain areas using brain registration and analysis of SPECT studies (BRASS; Nuclear Diagnostics AB, Stockholm (Sweden)) on both SPECT and DSC-MRI. Results: Voxel-based correlation between coregistered SPECT and DSC-MR showed a high correlation, with a mean correlation coefficient of 0.94. ROI analyses of 24 regions showed significant differences between the control group and AD patients in 10 regions using SPECT and five regions in DSC-MR. Conclusion: SPECT remains superior to DSC-MRI in differentiating normal from pathological perfusion, and DSC-MRI could not replace SPECT in the diagnosis of patients with Alzheimer disease

  9. All-Optical Fiber Hanbury Brown & Twiss Interferometer to study 1300 nm single photon emission of a metamorphic InAs Quantum Dot

    Science.gov (United States)

    Muñoz-Matutano, G.; Barrera, D.; Fernández-Pousa, C. R.; Chulia-Jordan, R.; Seravalli, L.; Trevisi, G.; Frigeri, P.; Sales, S.; Martínez-Pastor, J.

    2016-06-01

    New optical fiber based spectroscopic tools open the possibility to develop more robust and efficient characterization experiments. Spectral filtering and light reflection have been used to produce compact and versatile fiber based optical cavities and sensors. Moreover, these technologies would be also suitable to study N-photon correlations, where high collection efficiency and frequency tunability is desirable. We demonstrated single photon emission of a single quantum dot emitting at 1300 nm, using a Fiber Bragg Grating for wavelength filtering and InGaAs Avalanche Photodiodes operated in Geiger mode for single photon detection. As we do not observe any significant fine structure splitting for the neutral exciton transition within our spectral resolution (46 μeV), metamorphic QD single photon emission studied with our all-fiber Hanbury Brown & Twiss interferometer could lead to a more efficient analysis of entangled photon sources at telecom wavelength. This all-optical fiber scheme opens the door to new first and second order interferometers to study photon indistinguishability, entangled photon and photon cross correlation in the more interesting telecom wavelengths.

  10. Red single-photon emission from an InP /GaInP quantum dot embedded in a planar monolithic microcavity

    Science.gov (United States)

    Roßbach, Robert; Reischle, Matthias; Beirne, Gareth J.; Jetter, Michael; Michler, Peter

    2008-02-01

    Using micro-photoluminescence, we demonstrate single-photon emission in the visible (red) spectral range using self-assembled InP quantum dots embedded in a planar microcavity realized by monolithically grown high reflectivity AlGaAs distributed Bragg reflectors. A full width at half maximum of 130μeV at 5K was observed from a single quantum dot coupled to the fundamental cavity resonance. Photon correlation measurements performed under continuous wave excitation show a clear antibunching behavior [g(2)(0)=0.13] as expected for a single-photon emitter. Saturation count rates up to 1.5MHz (8.1MHz into the first lens, with an extraction efficiency of 4.1%) were observed.

  11. Increased single-photon emission from InP/AlGaInP quantum dots grown on AlGaAs distributed Bragg reflectors

    Science.gov (United States)

    Roßbach, R.; Schulz, W.-M.; Reischle, M.; Beirne, G. J.; Jetter, M.; Michler, P.

    2008-11-01

    InP/GaInP quantum dots emitting in the red spectral range have been grown on an AlGaAs distributed Bragg reflector in order to increase the single-photon emission efficiency. We have observed an increase in ensemble photoluminescence by a factor of 28 in comparison to the reference InP/GaInP quantum dots grown without such a reflector underneath. Photon correlation measurements performed under pulsed excitation show a clear antibunching behavior ( g(0)=0.17) as expected for a single-photon emitter. Using aluminum containing barriers to surround the quantum dots the ensemble luminescence intensity could be increased by a factor of 500 at 240 K in comparison to the reference sample at 240 K.

  12. Superconducting Single Photon Detectors

    NARCIS (Netherlands)

    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 fluoresc

  13. Utility of single photon emission computed tomography/computed tomography imaging in evaluation of chronic low back pain

    International Nuclear Information System (INIS)

    Abnormal morphologic findings in imaging were thought to explain the etiology of low back pain (LBP). However, it is now known that variety of morphologic abnormalities is noted even in asymptomatic individuals. Single photon emission computed tomography/computed tomography (SPECT/CT) could be used to differentiate incidental findings from clinically significant findings. This study was performed to define the SPECT/CT patterns in patients with LBP and to correlate these with clinical and magnetic resonance imaging (MRI) findings. Thirty adult patients with LBP of duration 3 months or more were prospectively evaluated in this study. Patients with known or suspected malignancy, trauma or infectious processes were excluded. A detailed history of sensory and motor symptoms and neurologic examination was performed. All the patients were subjected to MRI and bone scintigraphy with hybrid SPECT/CT of the lumbo-sacral spine within 1 month of each other. The patients were classified into those with and without neurologic symptoms, activity limitation. The findings of clinical examination and imaging were compared. MRI and SPECT/CT findings were also compared. Thirty patients (18 men and 12 women; mean age 38 years; range 17-64 years) were eligible for the study. Clinically, 14 of 30 (46%) had neurologic signs and or symptoms. Six of the 30 patients (20%) had positive straight leg raising test (SLRT). Twenty-two of the 30 patients (73%) had SPECT abnormality. Most frequent SPECT/CT abnormality was tracer uptake in the anterior part of vertebral body with osteophytes/sclerotic changes. Significant positive agreement was noted between this finding and MRI evidence of degenerative disc disease. Only 13% of patients had more than one abnormality in SPECT. All 30 patients had MRI abnormalities. The most frequent abnormality was degenerative disc disease and facet joint arthropathy. MRI showed single intervertebral disc abnormality in 36% of the patients and more than one

  14. ASSESSMENT OF MYOCARDIAL VIABILITY WITH CONTRASTENHANCED MAGNETIC RESONANCE IMAGING AND COMPARISON WITH SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    Yi-ning Wang; Zheng-yu Jin; Zhu-hua Zhang; Ling-yan Kong; Li-bo Chen; Lu Zhou; Hong-yi Sun; Heng Zhang; Qi Miao

    2006-01-01

    Objective To compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease.Methods Twenty patients with suspected chronic ischemic heart disease underwent ceMRI and technetium-99m sestamibi single-photon emission computed tomography (SPECT).Patients with positive SPECT results also underwent 18F-fluorodeoxyglucose (FDG) SPECT.In a 17-segment model,the segmental extent of hyperenhancement (SEH) by ceMRI was compared with segmental FDG and sestamibi uptake by SPECT.Correlation between the extent of hyperenhancement by ceMRI and left ventricular function was analyzed.Results Seven patients got negative results both in ceMRI and technetium-99m sestamibi SPECT.The rest 13 patients with positive results then underwent 18F-FDG SPECT.In 221 segments of 13 patients,SEH was (2.1±8.2)%,(25.0±13.7)%,and (57.7±23.6)% in segments with normal metabolism/perfusion,metabolism/perfusion mismatch,and matched defects,respectively,and there were significant differences between either two of them (all P<0.05).By receiver operating characteristic curve analysis,the area under the curve was 0.95 for the differentiation between viable and non-viable segments.At the cutoff value of 34%,SEH optimally differentiated viable from non-viable segments defined by SPECT.Using this threshold,the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by SPECT were 92% and 93%,respectively.Hyperenhancement size by ceMRI was correlated negatively with the left ventricular ejection fraction (r=-0.90,P<0.01) and positively with left ventricular volumes (r=0.62 for end-diastolic volume,r=0.75 for end-systolic volume,both P<0.05).Conclusion CeMRI allows assessment of myocardial viability with a high accuracy in patients with chronic ischemic heart disease.

  15. Single photon emission computer tomography of dopamine transporters in monkeys and humans with 99mTc-TRODAT-1

    Institute of Scientific and Technical Information of China (English)

    胡平; 陈玲; 张海琴; 黎锦如; 梁宏

    2004-01-01

    Background The diagnosis of Parkinson's disease is presently based on non-specific symptoms. However, radionuclide dopamine transporters imaging can provide specific diagnostic tool for Parkinson's disease. This study was designed to investigate the effects of imaging of dopamine transporters with 99mTc-TRODAT-1 in early diagnosis or differential diagnosis of Parkinson's disease.Methods Nine normal monkeys were used to establish N-methyl-4-phenyl-1, 2, 3, 6-tetra-hydropyridine (MPTP) hemi-Parkinsonian animal models, and they were subjected to imaging. Twenty-nine patients with Parkinson's disease, 12 age-matched healthy volunteers, and 18 age-matched patients with Parkinson's syndrome were investigated. Single photon emission computer tomography (SPECT) was performed 3 hours after intravenous injection of 740 MBq 99mTc-TRODAT-1. Striatum specific uptake of 99mTc-TRODAT-1 was calculated according to the ratio of striatum (ST) to cerebellum (CB)in dopamine transporters uptake.Results In normal monkeys, bilateral ratio of ST/CB was 2.34±0.41. After the injection of MPTP, uptake rate of 99mTc-TRODAT-1 at damaged region was much lower than that at the contralateral region, resulting in a significant difference in the ratio of ST/CB (right: ST/CB=1.73±0.35; left: ST/CB=1.90±0.30), especially in hemi-Parkinsonian model monkeys (right: ST/CB=1.29±0.17; left: ST/CB=1.80±0.33). The ratios of ST/CB were 1.57±0.17 and 1.61±0.14 for the right and left respectively in the healthy volunteers, 1.04±0.29 and 1.06±0.30 in the age-matched patients with Parkinson's disease, and 1.56±0.17 and 1.59±0.18 in the age-matched patients with Parkinson's disease syndrome. A significant difference was noted between group of Parkinson's disease, normal controls and Parkinson's disease syndrome. Conclusion The results suggest that 99mTc-TRODAT-1 dopamine transporters SPECT has clinical application value in early diagnosis or differential diagnosis of Parkinson's disease.

  16. Protection of lung function by introducing single photon emission computed tomography lung perfusion image into radiotherapy plan of lung cancer

    Institute of Scientific and Technical Information of China (English)

    YIN Yong; CHEN Jin-hu; LI Bao-sheng; LIU Tong-hai; LU jie; BAI Tong; DONG Xiao-ling; YU Jin-ming

    2009-01-01

    Background The lung functional status could be displayed on lung perfusion images. With the images, the radiotherapy plans of lung cancer could be guided to more optimized. This study aimed to assess quantitatively the impact of incorporating functional lung imaging into 3-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy (IMRT) planning for non-small cell lung cancer (NSCLC).Methods Ten patients with NSCLC who had undergone radiotherapy were included in this study. Before radiotherapy,each patient underwent CT simulation and lung perfusion imaging with single photon emission computed tomography (SPECT). The SPECT images were registered with simulation planning CT and used to contour functional lung (lung-F) and non-functional lung (lung-NF). Two 3DCRT plans and two IMRT plans were designed and compared in each patient:two anatomic plans using simulation CT alone and two functional plans using SPECT-CT in addition to the simulation CT.Dosimetric parameters of the four types of plans were compared in terms of tumor coverage and avoidance of normal tissues. Total radiation dose was set at 66 Gy (2 Gy×33 fractions).Results In incorporating perfusion information in 3DCRT and IMRT planning, the reductions on average in the mean doses to the functional lung in the functional plan were 168 cGy and 89 cGy, respectively, compared with those in the anatomic plans. The median reductions in the percentage of volume irradiated with >5 Gy, >10 Gy, >20 Gy, >30 Gy and >40 Gy for functional lung in the functional plans were 6.50%, 10.21%, 14.02%, 22.30% and 23.46% in 3DCRT planning,respectively, and 3.05%, 15.52%, 14.16%, 4.87%, and 3.33% in IMRT planning, respectively. No greater degree of sparing of the functional lung was achieved in functional IMRT than in 3DCRT.Conclusion Function-guided 3DCRT and IMRT plannings both appear to be effective in preserving functional lung in NSCLC patients.

  17. Single-photon imaging

    CERN Document Server

    Seitz, Peter

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

  18. Technetium-99m hexamethylpropylene amine oxime single-photon emission tomography of regional cerebral blood flow in insulin-dependent diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Keymeulen, B. [Dept. of Internal Medicine, Academic Hospital VUB, Brussels (Belgium); Metz, K. de [Dept. of Nuclear Medicine, Academic Hospital VUB, Brussels (Belgium); Cluydts, R. [Dept. of Psychology, Academic Hospital VUB, Brussels (Belgium); Bossuyt, A. [Dept. of Nuclear Medicine, Academic Hospital VUB, Brussels (Belgium); Somers, G.

    1996-02-01

    The study was performed to investigate subclinical abnormalities in regional cerebral blood flow (rCBF) in patients with insulin-dependent diabetes mellitus (IDDM) and to correlate them with patients` characteristics. After intravenous injection of technetium-99m hexamethylpropylene amine oxime (HMPAO), tracer uptake of the prefrontal, frontal and parieto-occipital zones was measured with a triple-head single-photon emission tomography (SPET) camera system in 35 IDDM patients outside an episode of hypolycaemia. Tracer uptake values in 16 age- and sex-matched healthy volunteers served as reference values. Compared with healthy subjects, increased tracer uptake of both prefrontal regions and the left frontal region could be shown in diabetes. Tracer uptake was negatively correlated with the duration of diabetes in all investigated regions. In diabetic patients with a disease duration of more than 5 years (n=26), stepwise regression analysis revealed a significant positive correlation between their HbA1c levels and tracer uptake. Long-term diabetic patients with reduced (pre)frontal tracer uptake (n=8) had lower HbA1c levels than those without (8.4%{+-}0.2% vs 9.3%{+-}0.3%, P<0.05) and tended to have more frequently a history of hypoglycaemic coma (6/8 v 6/18, P=0.06). It can be concluded that duration of diabetes contributes to subclinical changes in basal rCBF in IDDM as detected with HMPAO SPET of the brain. The positive correlation between the presence of regional hypoperfusion and lower HbA1c levels in long-term diabetic patients may be interpreted in the light of presumed higher incidence of hypoglycaemia as metabolic control improves. (orig.)

  19. Possibilities of the new hybrid technology single photon emission computer technology/computer tomography (SPECT/CT) and the first impressions of its application

    International Nuclear Information System (INIS)

    With the help of the new hybrid technique SPECT/ CT it is possible, using the only investigation, to acquire a combine image of the investigated organ, visualizing its function and structure. Combining the possibilities of the new multimodality method, which combines the possibilities of the Single Photon Emission Computer Tomography - SPECT and Computer Tomography - CT, it is possible to precisely localize the pathologically changed organs function. With the further combination of the tomographic gamma camera with diagnostic CT, a detailed morphological evaluation of the finding was possible. The main clinical application of the new hybrid diagnostic is in the fields of cardiology, oncology, orthopedics with more and more extension of those, not connected with oncology, such as - thyroid, parathyroid, brain (especially localization of the epileptic foci), visualization of local infection and recently for the purposes of the radiotherapy planning. According to the literature data, around 35% of SPECT-investigations have to be combined with CT in order to increase the specificity of the diagnosis, which changes the interpretation of the result in 56% of the cases. After installation of the SPECT/CT camera in the University hospital 'Alexandrovska' in January 2009, the following changes have been done: the number of the investigated patients have increased, including number of heart, thyroid (especially scintigraphy with 131I), bones and parathyroid glands. As a result of the application of the hybrid technique, a shortage of the investigated time was realized and a decrease prize in comparison with the individual application of the investigations. Summarizing the literature data and the preliminary impression of the first multimodality scanner in our country in the University hospital 'Alexandrovska' it could be said, that there is continuously increasing information for the new clinical applications of SPECT/CT. It is now accepted, that its usage will increase in

  20. Decrease in benzodiazepine receptor binding in a patient with Angelman syndrome detected by iodine-123 iomazenil and single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Odano, Ikuo [Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan); Anezaki, Toshiharu [Dept. of Neurology, Brain Research Inst., Niigata Univ., Niigata (Japan); Ohkubo, Masaki [Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan); Yonekura, Yoshiharu [Nihon Medi-Physics Co. Ltd., Hyogo (Japan); Onishi, Yoshihiro [Biomedical Imaging Research Center, Fukui Medical School, Fukui (Japan); Inuzuka, Takashi [Dept. of Neurology, Brain Research Inst., Niigata Univ., Niigata (Japan); Takahashi, Makoto [Dept. of Radiology, Niigata Univ. School of Medicine, Niigata (Japan); Tsuji, Shoji [Dept. of Neurology, Brain Research Inst., Niigata Univ., Niigata (Japan)

    1996-05-01

    A receptor mapping technique using iodine-123 iomazenil and single-photon emission tomography (SPET) was employed to examine benzodiazepine receptor binding in a patient with Angelman syndrome (AS). AS is characterized by developmental delay, seizures, inappropriate laughter and ataxic movement. In this entity there is a cytogenic deletion of the proximal long arm of chromosome 15q11-q13, where the gene encoding the GABA{sub A} receptor {beta}3 subunit (GABRB3) is located. Since the benzodiazepine receptor is constructed as a receptor-ionophore complex that contains the GABA{sub A} receptor, it is a suitable marker for GABA-ergic synapsis. To determine whether benzodiazepine receptor density, which indirectly indicates changes in GABA{sub A} receptor density, is altered in the brain in patients with AS, we investigated a 27-year-old woman with AS using {sup 123}I-iomazenil and SPET. Receptor density was quantitatively assessed by measuring the binding potential using a simplified method. Regional cerebral blood flow was also measured with N-isopropyl-p-[{sup 123}]iodoamphetamine. We demonstrated that benzodiazepine receptor density is severely decreased in the cerebellum, and mildly decreased in the frontal and temporal cortices and basal ganglia, a result which is considered to indicate decreased GABA{sub A} receptor density in these regions. Although the deletion of GABRB3 was not observed in the present study, we indirectly demonstrated the disturbance of inhibitory neurotransmission mediated by the GABA{sub A} receptor in the investigated patient. {sup 123}I-iomazenil with SPET was useful to map benzodiazepine receptors, which indicate GABA{sub A} receptor distribution and their density. (orig.)

  1. Single photon quantum cryptography.

    Science.gov (United States)

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

    2002-10-28

    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 color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

  2. SemiSPECT: A small-animal single-photon emission computed tomography (SPECT) imager based on eight cadmium zinc telluride (CZT) detector arrays

    OpenAIRE

    Kim, Hyunki; Furenlid, Lars R.; Crawford, Michael J.; Wilson, Donald W.; Barber, H. Bradford; Todd E. Peterson; Hunter, William C. J.; Liu, Zhonglin; Woolfenden, James M.; Barrett, Harrison H.

    2006-01-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm × 2.7 cm × ~ 0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 × 64 pixel array by photolithography. The ASIC is attached to ...

  3. An Incidentally Found Inflamed Uterine Myoma Causing Low Abdominal Pain, Using Tc-99m-Tektrotyd Single Photon Emission Computed Tomography-CT Hybrid Imaging

    OpenAIRE

    Zandieh, Shahin; Schütz, Matthias; Bernt, Reinhard; Zwerina, Jochen; Haller, Joerg

    2013-01-01

    We report the case of a 50-year-old woman presented with a history of right hemicolectomy due to an ileocecal neuroendocrine tumor and left breast metastasis. Owing to a slightly elevated chromogranin A-level and lower abdominal pain, single photon emission computed tomography-computer tomography (SPECT-CT) was performed. There were no signs of recurrence on the SPECT-CT scan, but the patient was incidentally found to have an inflamed intramural myoma. We believe that the slightly elevated ch...

  4. An interesting case of polyostotic fibrous dysplasia: The “pirate sign” evaluated with Tc-99m methylene diphosphonate single-photon emission computed tomography/computerized tomography

    International Nuclear Information System (INIS)

    Polyostotic fibrous dysplasia is a rare progressive benign disorder of the bone. Bone scintigraphy is extremely useful in the initial evaluation for identifying the extent of disease. We report a case presenting with pathological fracture of the shaft of the right femur. After treatment of the fracture, bone scintigraphy revealed involvement of multiple bones including the skull and facial bones. The utility of single-photon emission computed tomography/computerized tomography in the evaluation of the extent of skull base involvement is highlighted

  5. A single photon emission computed tomography scan study of striatal dopamine D2 receptor binding with 123I-epidepride in patients with schizophrenia and controls.

    OpenAIRE

    Tibbo, P; Silverstone, P H; McEwan, A. J.; Scott, J; Joshua, A; Golberg, K

    1997-01-01

    The usefulness of 123I-epidepride as a single photon emission computed tomography (SPECT) scan D2 receptor ligand was examined in vivo in 13 medicated patients with schizophrenia and age- and sex-matched normal controls. To establish the effect of endogenous dopamine on 123I-epidepride binding, 4 of the 13 controls also received 20 mg D-amphetamine. The results showed that 123I-epidepride had high specific binding to the striatum in both patients with schizophrenia and normal controls. There ...

  6. Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode

    International Nuclear Information System (INIS)

    We report on the enhancement of the spontaneous emission in the visible red spectral range from site-controlled InP/GaInP quantum dots by resonant coupling to Tamm-plasmon modes confined beneath gold disks in a hybrid metal/semiconductor structure. The enhancement of the emission intensity is confirmed by spatially resolved micro-photoluminescence area scans and temperature dependent measurements. Single photon emission from our coupled system is verified via second order autocorrelation measurements. We observe bright single quantum dot emission of up to ∼173 000 detected photons per second at a repetition rate of the excitation source of 82 MHz, and calculate an extraction efficiency of our device as high as 7%

  7. Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode

    Energy Technology Data Exchange (ETDEWEB)

    Braun, T.; Baumann, V.; Iff, O.; Schneider, C.; Kamp, M. [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); Höfling, S. [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany); SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-01-26

    We report on the enhancement of the spontaneous emission in the visible red spectral range from site-controlled InP/GaInP quantum dots by resonant coupling to Tamm-plasmon modes confined beneath gold disks in a hybrid metal/semiconductor structure. The enhancement of the emission intensity is confirmed by spatially resolved micro-photoluminescence area scans and temperature dependent measurements. Single photon emission from our coupled system is verified via second order autocorrelation measurements. We observe bright single quantum dot emission of up to ∼173 000 detected photons per second at a repetition rate of the excitation source of 82 MHz, and calculate an extraction efficiency of our device as high as 7%.

  8. A combined nuclear medicine protocol, including dynamic renal scintigraphy and single photon emission computed tomography (SPECT/CT) in patients with urolithiasis

    International Nuclear Information System (INIS)

    Full text: The aim is to present a combined nuclear medicine protocol, applied for the firs time in the Clinic of Nuclear Medicine, University Hospital Alexandrovska, including Dynamic Renal Scintigraphy and Single Photon Emission Computed Tomography (SPECT/CT) for the diagnosis of urolithiasis and its complications. The imaging protocol included the following procedures included dynamic renal scintigraphy (DRS) in supine position, performed by the injection of 74-185 MBq 99mTc-MAG 3, matrix 128x128 and a low energy high resolution collimator, followed by Single Photon Emission Tomography/Computed Tomography (SPECT/CT) of the kidneys, ureters, and urinary bladder, performed immediately after the end of the DRS in the same position of the patient. The combined protocol is applied in 50 patients with known or suspected urolithiasis.A functional time/activity curves were derived - renograms form each kidney. The basic quantitative and semi-quantitative parameters were calculated. The CT images were reconstructed in 5 mm intervals on abdominal and bone window with B20s smooth filter. The proposed combined nuclear medicine protocol allows for complex diagnosis of urolithiasis, including not only functional, but also morphological information through CT visualization of renal structures and exact localization of the stones

  9. Semi-automatic quantification of regional cerebral perfusion in primary degenerative dementia using 99mTc-HMPAO and single photon emission tomography

    International Nuclear Information System (INIS)

    A new semi-automatic method for quantifying regional cerebral uptake of 99mTc-HMPAO was used to assess single photon emission tomograms from 5 normal subjects, 14 patients with Alzheimer's disease, 14 patients with dementia of frontal lobe type and 4 patients with dementia with motor neurone disease. Uptake in both posterior cortical regions, although not in other regions, was significantly lower (P<0.05) in Alzheimer's disease than in normal controls. Conversely in both dementia of frontal lobe type and dementia with motor neurone disease, uptake was significantly reduced (P<0.05) compared with controls in all anterior cortical regions but not in posterior regions. Numerical findings in each disease mirrored the pattern of reduced tracer uptake previously reported by visual assessment. Nine patients were re-examined after an interval of at least 1 year. Comparison of follow-up scans with original images showed significant decreases in mid-anterior, left anterior and left posterior cortical uptake (P<0.01) in patients with Alzheimer's disease and in left middle, left posterior and right posterior cortical uptake (P<0.01) in patients with dementia of frontal lobe type. The method of quantification may be a useful adjunct to the visual assessment of single photon emission tomograms. (orig.)

  10. Single photon emission up to liquid nitrogen temperature from charged excitons confined in GaAs-based epitaxial nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Dusanowski, Ł., E-mail: lukasz.dusanowski@pwr.edu.pl; Syperek, M.; Maryński, A.; Misiewicz, J.; Sęk, G. [Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław (Poland); Li, L. H. [Ecole Polytechnique Fédérale de Lausanne, Institute of Quantum Electronics and Photonics, Station 3, CH-1015 Lausanne (Switzerland); Höfling, S. [Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, University of Würzburg, Am Hubland, D-97074 Würzburg (Germany); SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, KY16 9SS St. Andrews (United Kingdom); Kamp, M. [Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, University of Würzburg, Am Hubland, D-97074 Würzburg (Germany); Fiore, A. [Ecole Polytechnique Fédérale de Lausanne, Institute of Quantum Electronics and Photonics, Station 3, CH-1015 Lausanne (Switzerland); COBRA Research Institute, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2015-06-08

    We demonstrate a non-classical photon emitter at near infrared wavelength based on a single (In,Ga)As/GaAs epitaxially grown columnar quantum dot. Charged exciton complexes have been identified in magneto-photoluminescence. Photon auto-correlation histograms from the recombination of a trion confined in a columnar dot exhibit sub-Poissonian statistics with an antibunching dip yielding g{sup (2)}(0) values of 0.28 and 0.46 at temperature of 10 and 80 K, respectively. Our experimental findings allow considering the GaAs-based columnar quantum dot structure as an efficient single photon source operating at above liquid nitrogen temperatures, which in some characteristics can outperform the existing solutions of any material system.

  11. Simple partial status epilepticus localized by single-photon emission computed tomography subtraction in chronic cerebral paragonimiasis.

    Science.gov (United States)

    Joo, Eun Yeon; Kim, Jee Hyun; Tae, Woo Suk; Han, Sun Jung; Kim, Seunghwan; Kim, Myoung-Hee; Byun, Hong Sik; Hong, Seung Bong

    2004-10-01

    A patient with chronic cerebral paragonimiasis began to have new motor seizures of the right face manifested by clonic contractions that occurred several hundred times a day, consistent with simple partial status epilepticus. Ictal electroencephalogram discharges started from the left frontal region and then spread to the left hemisphere with left frontal maximum. But clinical seizures were limited to the right face. The frequent partial seizures were controlled by the intravenous infusion of phenytoin. Brain magnetic resonance imaging showed multiple conglomerated round nodules with encephalomalacia in the left temporal and occipital lobes. Applying the technique of ictal-interictal single-photo emission computed tomography subtraction, the authors were able to localize the focal ictal-hyperperfusion on left precentral cortex adjacent to the lesions that correspond to the anatomical distribution of left face motor area.

  12. Narrow-band single photon emission at room temperature based on a single Nitrogen-vacancy center coupled to an all-fiber-cavity

    CERN Document Server

    Albrecht, Roland; Pauly, Christoph; Mücklich, Frank; Schell, Andreas W; Engel, Philip; Schröder, Tim; Benson, Oliver; Reichel, Jakob; Becher, Christoph

    2014-01-01

    We report the realization of a device based on a single Nitrogen-vacancy (NV) center in diamond coupled to a fiber-cavity for use as single photon source (SPS). The device consists of two concave mirrors each directly fabricated on the facets of two optical fibers and a preselected nanodiamond containing a single NV center deposited onto one of these mirrors. Both, cavity in- and output are directly fiber-coupled and the emission wavelength is easily tunable by variation of the separation of the two mirrors with a piezo-electric crystal. By coupling to the cavity we achieve an increase of the spectral photon rate density by two orders of magnitude compared to free-space emission of the NV center. With this work we establish a simple all-fiber based SPS with promising prospects for the integration into photonic quantum networks.

  13. Direct evidence of single quantum dot emission from GaN islands formed at threading dislocations using nanoscale cathodoluminescence: A source of single photons in the ultraviolet

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Berger, Christoph; Veit, Peter; Metzner, Sebastian; Bertram, Frank; Bläsing, Jürgen; Dadgar, Armin; Strittmatter, André; Christen, Jürgen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, 39106 Magdeburg (Germany); Callsen, Gordon; Kalinowski, Stefan; Hoffmann, Axel [Institute of Solid State Physics, Technical University Berlin, 10623 Berlin (Germany)

    2015-06-22

    Intense emission from GaN islands embedded in AlN resulting from GaN/AlN quantum well growth is directly resolved by performing cathodoluminescence spectroscopy in a scanning transmission electron microscope. Line widths down to 440 μeV are measured in a wavelength region between 220 and 310 nm confirming quantum dot like electronic properties in the islands. These quantum dot states can be structurally correlated to islands of slightly enlarged thicknesses of the GaN/AlN quantum well layer preferentially formed in vicinity to dislocations. The quantum dot states exhibit single photon emission in Hanbury Brown-Twiss experiments with a clear antibunching in the second order correlation function at zero time delay.

  14. Initial experience with SPECT (single-photon computerized tomography) of the brain using N-isopropyl I-123 p-iodoamphetamine: concise communication

    International Nuclear Information System (INIS)

    Forty-six patients were studied with N-isopropyl I-123 p-iodoamphetamine (IMP) and the Harvard Scanning Multidetector Brain System. In nine control patients, good differentiation between the gray and white matter of the cerebral cortex and the basal ganglia was evident. Regional uptake was affected by physiologic maneuvers (visual stimulation). In 24 patients studied for stroke, IMP images demonstrated areas that were involved in acute infarction in eight patients whose initial transmission computerized tomography (TCT) was normal; IMP also showed perfusion abnormalities larger than the TCT abnormality in ten patients. Perfusion abnormalities were present in 23/24 of these patients. Seven patients studied with a history of TIA had normal TCT and IMP images. In three patients studied during seizure activity, regions of hyperperfusion corresponded to the EEG seizure focus. Markedly decreased activity was present in three patients with brain tumor and corresponded to the focal abnormality on the TCT study. Our study demonstrates the feasibility of assessing regional brain perfusion using a radiopharmaceutical that is lipid soluble and has a high extraction fraction in the brain, together with single-photon ECT

  15. Phantom study to evaluate quantitative changes in myocardial radioisotope concentration for single photon emission computed tomography; Comparison between Tl-201 and Tc-99m

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Takashi; Kitabata, Yoshiki; Tanaka, Takeshi; Hasegawa, Mitsuo; Kato, Kazuzo (Cardiovascular Inst., Tokyo (Japan)); Okabe, Akifumi

    1990-01-01

    Quantitative changes in Tl-201 and Tc-99m in myocardial single photon emission computed tomography (SPECT) were evaluated using phantom studies. The absorption rate of gamma ray by the tissues surrounding the myocardium was less for Tc-99m (maximum, 61.2%) than Tl-201 (maximum, 70.8%). In studies on quantification of defects with various concentrations of the radioisotopes, Tc-99m was found superior to Tl-201. In comparing a focal defect in the anterior wall near the surface of the thorax (Defect A) with that in the posterior wall deep in the thorax (Defect B), Defect A had a better quantification than Defect B. Absorber, scattering, and background, however, precluded quantification, especially in Defect B. Although scatter subtraction may in part improve quantification, quantification seemed to be dependent on algorithm in image reconstruction, as well as spatial resolution of the equipment. (N.K.).

  16. Benzodiazepine receptor equilibrium constants for flumazenil and midazolam determined in humans with the single photon emission computer tomography tracer [123I]iomazenil

    DEFF Research Database (Denmark)

    Videbaek, C; Friberg, L; Holm, S;

    1993-01-01

    twice, once without receptor blockade and once with a constant degree of partial blockade of the benzodiazepine receptors by infusion of nonradioactive flumazenil (Lanexat) or midazolam (Dormicum). Single photon emission computer tomography and blood sampling were performed intermittently for 6 h after...... bolus injection of [123I]iomazenil. The tracer in plasma was determined by high-pressure liquid chromatography and also by a simple octanol extraction procedure. The free concentration of flumazenil and midazolam in plasma water averaged 52% and 3.5% of that in whole plasma. The Kd values for the entire...... cortical rim for flumazenil were 7.4, 10.0, 10.3 and 17.7 nmol/l plasma water and, for midazolam, 73, 76, 58 and 30 nmol/l plasma water. The variation exceeds random methodological error and is probably due to interindividual differences in receptor affinity. The Kd level of midazolam is considerably...

  17. 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)

  18. Normal regional distribution of cerebral blood flow in dogs: comparison between (99m) Tc-ethylcysteinate dimer and (99m) Tc- hexamethylpropylene amine oxime single photon emission computed tomography.

    Science.gov (United States)

    Adriaens, Antita; Polis, Ingeborgh; Waelbers, Tim; Vandermeulen, Eva; Dobbeleir, André; De Spiegeleer, Bart; Peremans, Kathelijne

    2013-01-01

    Functional imaging provides important insights into canine brain pathologies such as behavioral problems. Two (99m) Tc-labeled single photon emission computed tomography (SPECT) cerebral blood flow tracers-ethylcysteinate dimer (ECD) and hexamethylpropylene amine oxime (HMPAO)-are commonly used in human medicine and have been used previously in dogs but intrasubject comparison of both tracers in dogs is lacking. Therefore, this study investigated whether regional distribution differences between both tracers occur in dogs as is reported in humans. Eight beagles underwent two SPECT examinations first with (99m) Tc-ECD and followed by (99m) Tc-HMPAO. SPECT scanning was performed with a triple head gamma camera equipped with ultrahigh resolution parallel hole collimators. Images were reconstructed using filtered backprojection with a Butterworth filter. Emission data were fitted to a template permitting semiquantification using predefined regions or volumes of interest (VOIs). For each VOI, perfusion indices were calculated by normalizing the regional counts per voxel to total brain counts per voxel. The obtained perfusion indices for each region for both tracers were compared with a paired Student's T-test. Significant (P < 0.05) regional differences were seen in the subcortical region and the cerebellum. Both tracers can be used to visualize regional cerebral blood flow in dogs, however, due to the observed regional differences, they are not entirely interchangeable.

  19. Padrões de ativação cerebral em idosos sadios durante tarefa de memória verbal de reconhecimento: a single-photon emission computerized tomography study Brain activation patterns during verbal recognition memory in elderly healthy volunteers

    Directory of Open Access Journals (Sweden)

    Geraldo Busatto Filho

    2001-06-01

    Full Text Available INTRODUÇÃO: Estudos que utilizam as técnicas de PET, SPECT e ressonância magnética funcional têm permitido o mapeamento dos circuitos cerebrais ativados durante diversas tarefas cognitivas. O campo da memória declarativa tem sido um dos mais intensamente estudados. No presente estudo, usa-se a técnica de mapeamento do fluxo sangüíneo cerebral regional (FSCr por SPECT para investigar mudanças na atividade cerebral durante uma tarefa de memória episódica, em voluntários idosos sadios (n=15. MÉTODOS: Duas avaliações de SPECT foram realizadas na mesma sessão, usando a técnica de dose dividida do traçador 99 m-Tc-HMPAO. Medidas de FSCr foram registradas durante uma tarefa de reconhecimento de material verbal previamente aprendido e durante uma tarefa-controle mais simples. Comparações de FSCr foram realizadas automaticamente, utilizando o programa Statistical Parametric Mapping (SPM. RESULTADOS: Observou-se aumento de FSCr durante a tarefa de memória em várias regiões cerebrais, incluindo: córtex pré-frontal lateral bilateralmente (mais acentuadamente à esquerda; porções posteriores e mediais de córtex parieto-occipital à esquerda; hemisférios cerebelares bilateralmente; e córtex temporal lateral bilateralmente (pINTRODUCTION: PET, SPECT and functional magnetic resonance imaging studies have allowed the delineation of brain circuits activated during several types of cognitive tasks. The field of declarative memory has been one of the most extensively investigated. In the present study, the regional cerebral blood flow (rCBF SPECT technique was used to investigate changes in brain activity during a verbal memory task in a group of elderly healthy volunteers (n=15. METHODS:Two SPECT acquisitions were performed in the same session, using the split-dose 99mTc-HMPAO technique. Measures of rCBF were taken during a recognition memory task and a simpler control task. Between-task comparisons were performed automatically

  20. Imaging of soft-tissue tumors using L-3-[iodine-123]iodo-alpha-methyl-tyrosine single photon emission computed tomography : Comparison with proliferative and mitotic activity, cellularity, and vascularity

    NARCIS (Netherlands)

    Jager, PL; Plaat, BEC; de Vries, EGE; Molenaar, WM; Vaalburg, W; Piers, DA; Hoekstra, HJ

    2000-01-01

    The radiolabeled amino acid L-3.[I-123]-iodo-alpha-methyl-tyrosine (IMT) is a new tumor tracer that accumulates in many tumors and is suitable for single photon emission computed tomography (SPECT) imaging. Using IMT SPECT, we studied 32 patients with a soft-tissue tumor suspected to be a soft-tissu

  1. Imaging of soft-tissue tumors using L-3-[iodine-123]iodo-alpha-methyl-tyrosine single photon emission computed tomography: comparison with proliferative and mitotic activity, cellularity, and vascularity.

    NARCIS (Netherlands)

    Jager, P L; Plaat, B E; Vries, E G de; Molenaar, W M; Vaalburg, W; Piers, D A; Hoekstra, H J

    2000-01-01

    The radiolabeled amino acid L-3-[123I]-iodo-alpha-methyltyrosine (IMT) is a new tumor tracer that accumulates in many tumors and is suitable for single photon emission computed tomography (SPECT) imaging. Using IMT SPECT, we studied 32 patients with a soft-tissue tumor suspected to be a soft-tissue

  2. N-isopropyl-p-123I iodoamphetamine single photon emission computed tomography study of Parkinson's disease with dementia

    International Nuclear Information System (INIS)

    Intellectual deterioration occurs in 10-40% of patients with Parkinson's disease. However, there are many conflicting studies on its relation with brain perfusion and the nature of this dementing process remains controversial. The objective of this study was to compare cortical perfusion by SPECT using 123I-IMP between Parkinson's disease patients with dementia and those without dementia and to investigate the correlation between dementia in Parkinson's disease and brain perfusion in various areas. Fifty-two cases of Parkinson's disease and 10 control cases were studied. The Parkinson's disease with dementia group included 30 cases and the Parkinson's disease without dementia group included 22 cases. By multiple logistic regression method, we demonstrated significant hypoperfusion in the occipital cortex in Parkinson's disease with dementia. The cause of dementia in Parkinson's disease may vary. We demonstrated that occipital hypoperfusion was closely correlated to dementia in Parkinson's disease compared to frontal, parietal and temporal perfusion. (author)

  3. CdSe quantum dot in vertical ZnSe nanowire and photonic wire for efficient single-photon emission

    DEFF Research Database (Denmark)

    Cremel, Thibault; Bellet-Amalric, Edith; Cagnon, Laurent;

    conformal dielectric coating of Al2O3 on the NW-QDs using Atomic Layer Deposition so that a photonic wire is formed with the CdSe QD deterministically positioned on its axis. The collection enhancement effect is studied by measuring the emission (with pulse excitation, at saturation intensity) of single...

  4. 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.)

  5. Prediction of traumatic avascular necrosis of the femoral head by single photon emission computerized tomography and computerized tomography: an experimental study in dogs

    Directory of Open Access Journals (Sweden)

    SHEN Feng

    2012-02-01

    Full Text Available 【Abstract】 Objective: To evaluate the femoral head perfusion and to predict the traumatic avascular necrosis (AVN of the femoral head by single photon emission computerized tomography and computerized tomography (SPECT/CT. Methods: Totally 18 adult beagle dogs were divided randomly into three equal-sized (n=6 groups. Subsequently different degrees of ischemia model were developed by destroying blood vessels of the femoral head. The left hip received sham operation as normal control and the right hip underwent blood interruption. In Group A, the ligamentum teres was cut off. In Group B, the marrow cavity of the right femoral neck was destroyed while in Group C, the soft tissues at the base of the femoral neck were stripped in addition to the resection of the ligamentum teres and destruction of the marrow cavity. Three hours after surgery, SPECT/CT was performed. Laser Doppler Flowmetry (LDF measurements were also obtained at three different time points (before operation, immediately and three hours after operation in order to assess the change process of blood supply to the femoral head. Results: SPECT/CT showed no significant difference in the radionuclide uptake between the right and left femoral heads in Group A (t=-0.09, P=0.94 and Group B (t= 0.52, P=0.62. However, in Group C, it was 261±62 for the right femoral head, only 12% of that in the left femoral head. LDF measurements indicated that the femoral head perfusion was decreased from (45.0±3.3 PU to (39.1±3.7 PU in Group A, from (44.0±2.7 PU to (34.3±2.6 PU in Group B, and from (47.3±2.1 PU to (4.96±0.6 PU in Group C immediately after operation. However, the perfusion was restored and returned to normal values three hours after operation except in Group C. Conclusion: SPECT/CT could assess the perfusion of the femoral head semiquantitatively, which might be useful in predicting the development of traumatic AVN. Key words: Femur head necrosis; Femoral head; Tomography, emission

  6. Bright Single Photon Emitter in Silicon Carbide

    Science.gov (United States)

    Lienhard, Benjamin; Schroeder, Tim; Mouradian, Sara; Dolde, Florian; Trong Tran, Toan; Aharonovich, Igor; Englund, Dirk

    Efficient, on-demand, and robust single photon emitters are of central importance to many areas of quantum information processing. Over the past 10 years, color centers in solids have emerged as excellent single photon emitters. Color centers in diamond are among the most intensively studied single photon emitters, but recently silicon carbide (SiC) has also been demonstrated to be an excellent host material. In contrast to diamond, SiC is a technologically important material that is widely used in optoelectronics, high power electronics, and microelectromechanical systems. It is commercially available in sizes up to 6 inches and processes for device engineering are well developed. We report on a visible-spectrum single photon emitter in 4H-SiC. The emitter is photostable at both room and low temperatures, and it enables 2 million photons/second from unpatterned bulk SiC. We observe two classes of orthogonally polarized emitters, each of which has parallel absorption and emission dipole orientations. Low temperature measurements reveal a narrow zero phonon line with linewidth < 0.1 nm that accounts for more than 30% of the total photoluminescence spectrum. To our knowledge, this SiC color emitter is the brightest stable room-temperature single photon emitter ever observed.

  7. MediSPECT: Single photon emission computed tomography system for small field of view small animal imaging based on a CdTe hybrid pixel detector

    Science.gov (United States)

    Accorsi, R.; Autiero, M.; Celentano, L.; Chmeissani, M.; Cozzolino, R.; Curion, A. S.; Frallicciardi, P.; Laccetti, P.; Lanza, R. C.; Lauria, A.; Maiorino, M.; Marotta, M.; Mettivier, G.; Montesi, M. C.; Riccio, P.; Roberti, G.; Russo, P.

    2007-02-01

    We describe MediSPECT, a new scanner developed at University and INFN Napoli, for SPECT studies on small animals with a small field of view (FOV) and high spatial resolution. The CdTe pixel detector (a 256×256 matrix of 55 μm square pixels) operating in single photon counting for detection of gamma-rays with low and medium energy (e.g. 125I, 27-35 keV, 99mTc, 140 keV), is bump bonded to the Medipix2 readout chip. The FOV of the MediSPECT scanner with a coded aperture mask collimator ranges from 6.3 mm (system spatial resolution 110 μm at 27-35 keV) to 24.3 mm. With a 0.30 mm pinhole the FOV ranges from 2.4 to 29 mm (where the system spatial resolution is 1.0 mm at 27-35 keV and 2.0 mm at 140 keV). MediSPECT will be used for in vivo imaging of small organs or tissue structures in mouse, e.g., brain, thyroid, heart or tumor.

  8. Microscopic theory of indistinguishable single-photon emission from a quantum dot coupled to a cavity: The role of non-Markovian phonon-induced decoherence

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Lodahl, Peter; Jauho, Antti-Pekka;

    2013-01-01

    We study the fundamental limit on single-photon indistinguishability imposed by decoherence due to phonon interactions in semiconductor quantum dot-cavity quantum electrodynamics systems. Employing an exact diagonalization approach we find large differences compared to standard methods...

  9. Effect of partial volume correction on muscarinic cholinergic receptor imaging with single-photon emission tomography in patients with temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Animal experiments and preliminary results in humans have indicated alterations of hippocampal muscarinic acetylcholine receptors (mAChR) in temporal lobe epilepsy. Patients with temporal lobe epilepsy often present with a reduction in hippocampal volume. The aim of this study was to investigate the influence of hippocampal atrophy on the quantification of mAChR with single photon emission tomography (SPET) in patients with temporal lobe epilepsy. Cerebral uptake of the muscarinic cholinergic antagonist [123I]4-iododexetimide (IDex) was investigated by SPET in patients suffering from temporal lobe epilepsy of unilateral (n=6) or predominantly unilateral (n=1) onset. Regions of interest were drawn on co-registered magnetic resonance images. Hippocampal volume was determined in these regions and was used to correct the SPET results for partial volume effects. A ratio of hippocampal IDex binding on the affected side to that on the unaffected side was used to detect changes in muscarinic cholinergic receptor density. Before partial volume correction a decrease in hippocampal IDex binding on the focus side was found in each patient. After partial volume no convincing differences remained. Our results indicate that the reduction in hippocampal IDex binding in patients with epilepsy is due to a decrease in hippocampal volume rather than to a decrease in receptor concentration. (orig.). With 2 figs., 2 tabs

  10. Demonstration of a reduction in muscarinic receptor binding in early Alzheimer's disease using iodine-123 dexetimide single-photon emission tomography

    International Nuclear Information System (INIS)

    Decreased muscarinic receptor binding has been suggested in single-photon emission tomography (SPET) studies of Alzheimer's disease. However, it remains unclear whether these changes are present in mildly demented patients, and the role of cortical atrophy in receptor binding assessment has not been investigated. We studied muscarinic receptor binding normalized to neostriatum with SPET using [123I[4-iododexetimide in five mildly affected patients with probable Alzheimer's disease and in five age-matched control subjects. Region of interest (ROI) analysis was performed in a consensus procedure blind to clinical diagnosis using matched magnetic resonance (MRI) images. Cortical atrophy was assessed by calculating percentages of cerebrospinal fluid in each ROI. An observer study with three observers was conducted to validate this method. Alzheimer patients showed statistically significantly less [123I[4-iododexetimide binding in left temporal and right temporo-parietal cortex compared with controls, independent of age, sex and cortical atrophy. Mean intra-observer variability was 3.6% and inter-observer results showed consistent differences in [123I[4-iododexetimide binding between observers. However, differences between patients and controls were comparable among observers and statistically significant in the same regions as in the consensus procedure. Using an MRI-SPET matching technique, we conclude that [123I[4-iododexetimide binding is reduced in patients with mild probable Alzheimer's disease in areas of temporal and temporo-parietal cortex. (orig.). With 1 fig., 4 tabs

  11. A study of cerebral hemodynamics in various cerebrovascular disorders by means of rCBF measurement with single photon emission computed tomography

    International Nuclear Information System (INIS)

    Using single photon emission computed tomography (SPECT) with Xe-133 inhalation method, regional cerebral blood flow (rCBF) was measured for the purpose of analyzing the pathophysiology of various cerebrovascular disorders. Included in this series were 38 normal volunteers (N), 72 patients with ischemic cerebrovascular disease (ICD), 16 with subarachnoid hemorrhage (SAH), 9 with arteriovenous malformation (AVM), 6 with Moyamoya disease (MD), and 4 with hypertensive intracerebral hematoma (HIH). In the N group, rCBF was independent of sex and laterality. Increased rCBF was observed in the frontal region, as compared with other regions. A significantly increased rCBF was observed in the thirties decade of life; the difference in rCBF was, however, not statistically significant above the age of 30 years. In the ICD group, rCBF decreased in association with severer disorder. In cases of severe disorder, a significantly decreased rCBF was observed in the whole area, as compared with the control group. SPECT allowed early detection of decreased rCBF due to vaso-spasm in the SAH group. The groups of AVM, MD, and HIH showed decreased rCBF in the surrounding areas of the lesions. (Namekawa, K.)

  12. Immunotargeting of Integrin α6β4 for Single-Photon Emission Computed Tomography and Near-Infrared Fluorescence Imaging in a Pancreatic Cancer Model

    Directory of Open Access Journals (Sweden)

    Winn Aung MBBS, PhD

    2016-01-01

    Full Text Available To explore suitable imaging probes for early and specific detection of pancreatic cancer, we demonstrated that α6β4 integrin is a good target and employed single-photon emission computed tomography (SPECT or near-infrared (NIR imaging for immunotargeting. Expression levels of α6β4 were examined by Western blotting and flow cytometry in certain human pancreatic cancer cell lines. The human cell line BxPC-3 was used for α6β4-positive and a mouse cell line, A4, was used for negative counterpart. We labeled antibody against α6β4 with Indium-111 (111In or indocyanine green (ICG. After injection of 111In-labeled probe to tumor-bearing mice, biodistribution, SPECT, autoradiography (ARG, and immunohistochemical (IHC studies were conducted. After administration of ICG-labeled probe, in vivo and ex vivo NIR imaging and fluorescence microscopy of tumors were performed. BxPC-3 tumor showed a higher radioligand binding in SPECT and higher fluorescence intensity as well as a delay in the probe washout in NIR imaging when compared to A4 tumor. The biodistribution profile of 111In-labeled probe, ARG, and IHC confirmed the α6β4 specific binding of the probe. Here, we propose that α6β4 is a desirable target for the diagnosis of pancreatic cancer and that it could be detected by radionuclide imaging and NIR imaging using a radiolabeled or ICG-labeled α6β4 antibody.

  13. Skull base osteomyelitis in otitis externa: The utility of triphasic and single photon emission computed tomography/computed tomography bone scintigraphy

    International Nuclear Information System (INIS)

    Skull base osteomyelitis (SBO) refers to infection that has spread beyond the external auditory canal to the base of the skull in advanced stages of otitis externa. Clinically, it may be difficult to differentiate SBO from severe otitis externa without bony involvement. This study was performed to determine the role of three phase bone scintigraphy (TPBS) and single photon emission tomography/computed tomography (SPECT/CT) in detecting SBO. We retrospectively analyzed records of 20 patients (14 M, 6 F) with otitis externa and suspected SBO. TPBS and SPECT/CT of the skull were performed. Findings were correlated with clinical, laboratory and diagnostic CT scan findings. All patients were diabetic with elevated erythrocyte sedimentation rate. A total of 18 patients had bilateral and two unilateral symptoms. Cranial nerves were involved in eight patients and microbiological culture of ear discharge fluid positive in seven. Early images showed increased temporal vascularity in nine patients and increased soft-tissue uptake in 10, while delayed images showed increased bone uptake in 19/20 patients. Localized abnormal tracer uptake was shown by SPECT/CT in the mastoid temporal (15), petrous (11), sphenoid (3) and zygomatic (1) and showed destructive changes in five. Thus, TPBS was found positive for SBO in 10/20 patients and changed the management in four. Our study suggests that TPBS with SPECT/CT is a useful non-invasive investigation for detection of SBO in otitis externa

  14. Can Dynamic Susceptibility Contrast Magnetic Resonance Imaging Replace Single-Photon Emission Computed Tomography in the Diagnosis of Patients with Alzheimer's Disease? A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Cavallin, L.; Danielsson, R.; Oeksengard, A.R.; Wahlund, L.O.; Julin, P.; Frank, A.; Engman, E.L.; Svensson, L.; Kristoffersen Wiberg, M. [Karolinska Univ. Hospital, Stockholm (Sweden). Div. of Radiology

    2006-11-15

    Purpose: To compare single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) in a cohort of patients examined for suspected dementia, including patients with no objective cognitive impairment (control group), mild cognitive impairment (MCI), and Alzheimer's disease (AD). Material and Methods: Twenty-four patients, eight with AD, 10 with MCI, and six controls were investigated with SPECT using {sup 99m}Tc-hexamethylpropyleneamine oxime (HMPAO) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with gadobutrol. Three observers performed a visual interpretation of the SPECT and MR images using a four-point visual scale. Results: SPECT was superior to DSC-MRI in differentiating normal from pathological. All three observers showed statistically significant results in discriminating between the control group, AD, and MCI by SPECT, with a P value of 0.0006, 0.04, and 0.01 for each observer. The statistical results were not significant for MR (P values 0.8, 0.1, and 0.2, respectively). Conclusion: DSC-MRI could not replace SPECT in the diagnosis of patients with Alzheimer's disease. Several patient- and method-related improvements should be made before this method can be recommended for clinical practice.

  15. Comparative study of thallium-201 single-photon emission computed tomography and electrocardiography in Duchenne and other types of muscular dystrophy

    International Nuclear Information System (INIS)

    Single-photon emission computed tomography (SPECT) using thallium-201 was compared with 12-lead electrocardiography (ECG) in patients with Duchenne (29), facioscapulohumeral (7), limb-girdle (6) and myotonic (5) dystrophies, by dividing the left ventricular (LV) wall into 5 segments. SPECT showed thallium defects (37 patients, mostly in the posteroapical wall), malrotation (23), apical aneurysm (5) and dilatation (7). ECG showed abnormal QRS (36 patients), particularly as a posterolateral pattern (13). Both methods of assessment were normal in only 7 patients. The Duchenne type frequently showed both a thallium defect (particularly in the posteroapical wall) and an abnormal QRS (predominantly in the posterolateral wall); the 3 other types showed abnormalities over the 5 LV wall segments in both tests. The percent of agreement between the 2 tests was 64, 66, 70, 72 and 72 for the lateral, apical, anteroseptal, posterior and inferior walls, respectively. The 2 tests were discordant in 31% of the LV wall, with SPECT (+) but ECG (-) in 21% (mostly in the apicoinferior wall) and SPECT (-) but ECG (+) in 10% (mostly in the lateral wall). Some patients showed large SPECT hypoperfusion despite minimal electrocardiographic changes. ECG thus appeared to underestimate LV fibrosis and to reflect posteroapical rather than posterolateral dystrophy in its posterolateral QRS pattern. In this disease, extensive SPECT hypoperfusion was also shown, irrespective of clinical subtype and skeletal involvement

  16. Comparison of 180° and 360° Arc Data Acquisition to Measure Scintigraphic Parameters from Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging: Is There Any Difference?

    Directory of Open Access Journals (Sweden)

    Hamid Javadi

    2016-02-01

    Full Text Available Objective: The aim of the current study was to compare 180° and 360° data collection modes to measure end diastolic volume (EDV, end systolic volume (ESV and ejection fraction (EF values of the cardiac system by gated myocardial perfusion tomography. Methods: Thirty-three patients underwent gated myocardial perfusion tomography. Single photon emission computed tomography data of patients’ heart were acquired by 180°, 45° left posterior oblique to 45° right anterior oblique, and 360° to obtain EDV, ESV, EF and cardiac volume changes (V1, V2, V3, V4, V5, V6, V7 and V8 throughout each cardiac cycle. Results: Results of the current study indicated that there were no significant differences between 180° and 360° angular sampling in terms of measuring EDV, ESV and EF in myocardial perfusion imaging. Cardiac volume change patterns during a cardiac cycle were also similar in 360° and 180° scans. We also observed that there was no difference in EDV, ESV and EF values between the group with stress induced by exercise and the group with stress imposed by dipyridamole. Conclusion: As there is no difference between 180°and 360° cardiac scanning in terms of EDV, ESV and EF, half-orbit scan is recommended to study these cardiac system parameters because it offers more comfort to patients and a shorter scanning time.

  17. Head sinuses, melon, and jaws of bottlenose dolphins, Tursiops truncatus, observed with computed tomography structural and single photon emission computed tomography functional imaging

    Science.gov (United States)

    Ridgway, Sam; Houser, Dorian; Finneran, James J.; Carder, Don; van Bonn, William; Smith, Cynthia; Hoh, Carl; Corbeil, Jacqueline; Mattrey, Robert

    2003-04-01

    The head sinuses, melon, and lower jaws of dolphins have been studied extensively with various methods including radiography, chemical analysis, and imaging of dead specimens. Here we report the first structural and functional imaging of live dolphins. Two animals were imaged, one male and one female. Computed tomography (CT) revealed extensive air cavities posterior and medial to the ear as well as between the ear and sound-producing nasal structures. Single photon emission computed tomography (SPECT) employing 50 mCi of the intravenously injected ligand technetium [Tc-99m] biscisate (Neurolite) revealed extensive and uptake in the core of the melon as well as near the pan bone area of the lower jaw. Count density on SPECT images was four times greater in melon as in the surrounding tissue and blubber layer suggesting that the melon is an active rather than a passive tissue. Since the dolphin temporal bone is not attached to the skull except by fibrous suspensions, the air cavities medial and posterior to the ear as well as the abutment of the temporal bone, to the acoustic fat bodies of each lower jaw, should be considered in modeling the mechanism of sound transmission from the environment to the dolphin ear.

  18. Assessment of Gastric Accommodation in Patients with Functional Dyspepsia by 99mTc-Pertechtenate Single Photon Emission Computed Tomography Imaging: Practical but not Widely Accepted

    Directory of Open Access Journals (Sweden)

    Taghi Amiriani

    2015-10-01

    Full Text Available Objective: Impaired gastric accommodation is one of the main symptoms in patients with functional dyspepsia. The aim of the present study was to assess gastric accommodation in patients with functional dyspepsia using single photon emission computed tomography (SPECT imaging. Methods: Twenty-four patients with functional dyspepsia and 50 healthy volunteers as control group were enrolled in this study. All participants were given 5 mCi 99mTc-pertechtenate intravenously, served with a low fat meal, and underwent SPECT scanning 20 minutes after the meal. Results: Based on the scintigraphic data, gastric volumes were found to be significantly increased after food ingestion in both patient and control groups. We also found that while there was no significant difference between patient and control groups in terms of fasting gastric volumes, postprandial gastric volume was significantly lower in patients as compared to healthy individuals (p<0.05. Conclusion: Measuring gastric volume by using SPECT can be a valuable method in the detection of functional dyspepsia and in differentiation of this entity from other organic disorders.

  19. Thallium-201 single photon emission computed tomography (SPECT) in patients with Duchenne's progressive muscular dystrophy. A histopathologic correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Toru; Yanagisawa, Atsuo; Sakata, Konomi; Shimoyama, Katsuya; Yoshino, Hideaki; Ishikawa, Kyozo [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine; Sakata, Hitomi; Ishihara, Tadayuki

    2001-02-01

    The pathomorphologic mechanism responsible for abnormal perfusion imaging during thallium-201 myocardial single photon emission computed tomography ({sup 201}Tl-SPECT) in patients with Duchenne's progressive muscular dystrophy (DMD) was investigated. Hearts from 7 patients with DMD were evaluated histopathologically at autopsy and the results correlated with findings on initial and delayed resting {sup 201}Tl-SPECT images. The location of segments with perfusion defects correlated with the histopathologically abnormal segments in the hearts. Both the extent and degree of myocardial fibrosis were severe, especially in the posterolateral segment of the left ventricle. Severe transmural fibrosis and severe fatty infiltration were common in segments with perfusion defects. In areas of redistribution, the degree of fibrosis appeared to be greater than in areas of normal perfusion; and intermuscular edema was prominent. Thus, the degree and extent of perfusion defects detected by {sup 201}Tl-SPECT were compatible with the histopathology. The presence of the redistribution phenomenon may indicate ongoing fibrosis. Initial and delayed resting {sup 201}Tl-SPECT images can predict the site and progress of myocardial degeneration in patients with DMD. (author)

  20. A single photon emission computed tomography scan study of striatal dopamine D2 receptor binding with 123I-epidepride in patients with schizophrenia and controls.

    Science.gov (United States)

    Tibbo, P; Silverstone, P H; McEwan, A J; Scott, J; Joshua, A; Golberg, K

    1997-01-01

    The usefulness of 123I-epidepride as a single photon emission computed tomography (SPECT) scan D2 receptor ligand was examined in vivo in 13 medicated patients with schizophrenia and age- and sex-matched normal controls. To establish the effect of endogenous dopamine on 123I-epidepride binding, 4 of the 13 controls also received 20 mg D-amphetamine. The results showed that 123I-epidepride had high specific binding to the striatum in both patients with schizophrenia and normal controls. There was a trend for the total striatal binding of medicated patients with schizophrenia, as measured by total basal ganglia: frontal cortex (TBG:FC) ratios, to be less than the binding of controls (P = 0.053). This trend confirms previous work showing that antipsychotic medication decreases the number of D2 receptors available for binding to the radioligand. Interestingly, there was also a significant relationship between 123I-epidepride binding ratios and global functioning scales (Global Assessment of Functioning scale [GAF]) for schizophrenia (r = 0.56, P = 0.045), although there was no such relationship with the Brief Psychiatric Rating Scale (BPRS). In addition, our results showed that amphetamine-induced dopamine release did not alter 123I-epidepride binding, confirming the high specific binding of 123I-epidepride to the D2 receptor. We conclude that 123I-epidepride appears to be a very useful SPECT ligand for imaging the D2 receptor. PMID:9002391

  1. Regional cerebral blood flow in acute stage with ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki; Iino, Katsuro; Kojima, Hisashi; Saito, Hitoshi; Suzuki, Mikio; Watanabe, Kazuo; Kato, Toshiro

    1987-05-01

    Single photon emission computed tomography (SPECT) with xenon-133 inhalation method was undertaken within 48 hr after the onset in 68 patients with ischemic cerebrovascular disease. The results for regional cerebral blood flow (rCBF) were compared with concurrently available computed tomography (CT) scans. In patients with cerebral infarction, SPECT detected ischemic lesions earlier than CT, with the detectability being 92 %. The area with a decreased blood flow, as seen on SPECT, was more extensive than the low density area on CT, with a concomitant decrease in blood flow in the contralateral cerebral hemisphere. Crossed cerebellar diaschisis was associated with stenosis of the internal carotid artery in 50 % (7/14), and with stenosis of the middle cerebral artery in 35 % (9/26). Abnormal SPECT findings were seen in 47 % (8/17) of the patients with transient ischemic attack (TIA). Five TIA patients had a decreased rCBF on SPECT, which was not provided by CT scans. On the contrary, small infarct lesions in the cerebral basal ganglia, as observed in 4 patients, was not detected by SPECT, but detected by CT. This may imply the limitations of SPECT in the detection of deep-seated lesions of the cerebrum. The results led to the conclusion that SPECT can be performed safely even in acute, seriously ill patients to know changes in rCBF because it is noninvasive and is capable of being repeated in a short time. (Namekawa, K.).

  2. Phantom study of thallium-201 myocadial single photon emission computed tomography for evaluating its ability to quantify residual myocardium in infarct area

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Tohru; Watanabe, Toshiaki; Kosaka, Noboru; Momose, Toshimitsu; Nishikawa, Junichi; Iio, Masahiro

    1988-03-01

    We studied the relationship between the count of myocardial wall in single photon emission computed tomography (SPECT) image and the thickness of wall or the concentration of Thallium-201 (Tl) in wall. For this purpose, we used phantom of thorax and myocardium. Thoracic phantom consists of mediastinum filled with low concentrated Tl solution and lung filled with wooden tip. Myocardial phantom consists of eight parts (upper and lower parts of anterior wall, septum, posteroinferior wall and lateral wall). In one phantom we changed the thickness of wall (10 mm, 7.5 mm, 5 mm, 2.5 mm, 0 mm) and in another phantom we changed the Tl concentration (100 %, 75 %, 50 %, 25 %, 0 %). In our results, the thickness and the concentration correlated well with the count and five grades (100 %, 75 %, 50 %, 25 %, 0 %) were well separated though it was said that SPECT is inaccurate in quantification. But in 180 deg half scan, the count of upper part was 10 - 15 % lower than that of lower part and the count of posteroinferior wall was about 10 % lower than that of anterior wall. We have to take it into account in quantification. In conclusion, using Tl-201 myocardial SPECT residual myocardium in infarct area can be evaluated from the severity of defect, and from that the severity of ischemia can be evaluated.

  3. Estimation of infarct size by three-dimensional surface display method of myocardial single photon emission CT with /sup 201/Tl

    Energy Technology Data Exchange (ETDEWEB)

    Kubota, Masahiro; Tsuda, Takatoshi; Akiba, Hidenari; Morita, Kazuo; Hosoba, Minoru; Ban, Ryuichi; Hirano, Takako

    1987-11-01

    To estimate infarct size, we devised three-dimensional (3D) surface display method of /sup 201/Tl myocardial single photon emission CT (SPECT). The method was performed with maximum-count circumferential profiles (CPs) of short axis views of /sup 201/Tl myocardial SPECT. The counts of maximum-count CP were put into a pixel line with the calculated left ventricular circumferential length on each short axis slice. A 3D-surface display map was created by arrangement of these pixel lines from apex to base of left ventricle in order. The sizes of defects in myocardial phantom were calculated by this method. There was a high correlation between the real defect sizes and the calculated defect sizes. In 6 patients with anterior myocardial infarction, the infarct sizes were calculated by this method. The extent of abnormality was identified by automatic computer comparison of each patient's profiles with corresponding lower limits of normal profiles. The infarct sizes calculated by 3D-surface display method were closely correlated not only with the infarct sizes calculated by summation of defect sizes in short axis views, but also with left ventricular ejection fractions. We concluded that the 3D-surface display method of /sup 201/Tl myocardial SPECT is effective for noninvasive assessment of the extent of myocardial infarction.

  4. Investigation of the effects of attenuation correction on the compatibility of two single photon emission computed tomography systems with the use of segmentation through registration

    Science.gov (United States)

    Lampaskis, M.; Killilea, K.; Metherall, P.; Harris, A.; Barber, D.

    2011-09-01

    The aim of this work was to compare images acquired from two Single Photon Emission Computed Tomography (SPECT), performing attenuation correction using different systems, to evaluate the level at which images from these systems can be used on patients to assess myocardial perfusion. The two systems are the Siemens E-cam with profile attenuation correction and the General Electric Hawkeye system. This study was performed using an anthropomorphic torso phantom. The motivation was to examine if attenuation corrected images from these systems are comparable when assessing the myocardial function of patients, with different conditions regarding background (adjacent tissues) activity and the presence or not of defects on the cardiac wall. To perform the analysis of the acquired images specialized software were used to extract information relating to the activity distribution within the cardiac insert (simulated myocardium). This was based on standardized myocardial segmentation used clinically, by the application of image registration using an artificial reference model. The results show that adjacent tissue activity did not affect the ability to detect defects. Further, the application of attenuation correction may reduce the comparability of the two systems to a small degree.

  5. Detection of vulnerable atherosclerosis plaques with a dual-modal single-photon-emission computed tomography/magnetic resonance imaging probe targeting apoptotic macrophages.

    Science.gov (United States)

    Cheng, Dengfeng; Li, Xiao; Zhang, Chunfu; Tan, Hui; Wang, Cong; Pang, Lifang; Shi, Hongcheng

    2015-02-01

    Atherosclerosis (AS), especially the vulnerable AS plaque rupture-induced acute obstructive vascular disease, is a leading cause of death. Accordingly, there is a need for an effective method to draw accurate predictions about AS progression and plaque vulnerability. Herein we report on an approach to constructing a hybrid nanoparticle system using a single-photon-emission computed tomography (SPECT)/magnetic resonance imaging (MRI) multimodal probe, aiming for a comprehensive evaluation of AS progression by achieving high sensitivity along with high resolution. Ultrasmall superparamagnetic iron oxide (USPIO) was covered by aminated poly(ethylene glycol) (PEG) and carboxylated PEG simultaneously and then functionalized with diethylenetriaminepentacetate acid for (99m)Tc coordination and subsequently Annexin V for targeting apoptotic macrophages abundant in vulnerable plaques. The in vivo accumulations of imaging probe reflected by SPECT and MRI were consistent and accurate in highlighting lesions. Intense radioactive signals detected by SPECT facilitated focus recognization and quantification, while USPIO-based T2-weighted MRI improved the focal localization and volumetry of AS plaques. For subsequent ex vivo planar images, targeting effects were further confirmed by immunohistochemistry, including CD-68 and TUNEL staining; meanwhile, the degree of concentration was proven to be statistically correlated with the Oil Red O staining results. In conclusion, these results indicated that the Annexin V-modified hybrid nanoparticle system specifically targeted the vulnerable AS plaques containing apoptotic macrophages and could be of great value in the invasively accurate detection of vulnerable plaques. PMID:25569777

  6. Imaging of dopamine D2 and somatostatin receptors in vivo using single-photon emission tomography in a patient with a TSH/PRL-producing pituitary macroadenoma

    International Nuclear Information System (INIS)

    A 28-year-old man with a thyroid stimulating hormone/prolactin (TSH/PRL)-secreting pituitary macroadenoma is discussed in relation to dopamine D2 and somatostatin receptor single-photon emission tomography (SPET). Somatostatin and dopamine D2 receptors were present on the tumour as visualised by SPET with the ligands indium-111-DTPA-octreotide (111In-SMS) and iodine-123 iodobenzamide (123I-IBZM), respectively. Therefore, treatment with octreotide 150 μg t.i.d. subcutaneously and bromocriptine 10 mg b.i.d. orally was given for >12 and >6 weeks, respectively. Following this treatment the visual defects disappeared, although tumour size, as measured by CT scanning, and serum TSH levels did not decrease. SPET with 111In-SMS and 123I-IBZM after therapy relvealed no change or a possible increase in somatostatin receptor binding potential and a possible decrease in dopamine D2 receptor binding potential. The lack of long-term effects of the medical treatment is discussed. It is concluded that a high somatostatin and dopamine D2 receptor binding potential in vivo in a TSH/PRL-producing adenoma does not necessarily predict a successful outcome of medicaal treatment. (orig./MG)

  7. Studies on Tl-201 single photon emission computed tomography (SPECT) of myocardium in patients with ischemic heart disease

    International Nuclear Information System (INIS)

    Seventy-six patients with IHD were divided into 2 groups, A) angina pectoris (n=50) and B) previous myocardial infarction(n=26). Each group was classified into three subgroups, without considering hypertension, that is 1) without complication, 2) with hypercholesterolemia, and 3) with diabetes mellitus. We studied and compared the findings of ECG, Echocardiogram (ECHO) and Emission CT (ECT) in these patients at rest. In the previous myocardial infarction group (Group B), we could find 100% ischemic patterns on ECG, 100% asynergy of either IVS or the posterior wall on ECHO and higher percentages of various grade of perfusion defects on ECT compared with group A. In group A, the percentages of perfusion defects were similar in three subgroups. But interestingly, in the hypercholesterolemic group, we could find diffuse moth-eaten like low perfusion areas on ECT. Further study is required whether this finding is peculiar for angina pectoris with hypercholesterolemia or an artifact on ECT. The percentage of ischemic patterns on ECG was lower than in the other groups. In angina pectoris with diabetes mellitus, asynergy in ECHO finding was a significantly higher percentage, compared with other groups. We believe, that ECG, ECHO and ECT are of compensatory importance in the diagnosis of patients with IHD. (author)

  8. Simultaneous multivessel coronary artery spasm demonstrated by quantitative analysis of thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    Thallium-201 myocardial scintigraphy with quantitative analysis of emission computed tomography was performed during episodes of angina in 19 patients with variant angina and nearly normal coronary arteriographic findings. Eleven patients (group I) were shown by arteriography to have spasm in 2 or more large coronary arteries. Eight patients (group II) had spasm in only 1 coronary artery. In 7 patients in group I, significant diffuse perfusion defects simultaneously appeared in multiple coronary artery regions on the scintigram (group IA). The extent and severity of the perfusion defect as measured by thallium-201 tomography were significantly greater in group IA than in group II (p less than 0.001 and p less than 0.01, respectively). The duration of transient ST-segment elevation during the attack in group IA was significantly longer than in group II (p less than 0.001). The incidence of ventricular arrhythmias, including ventricular tachycardia, or complete atrioventricular block during the anginal attack was significantly higher (p less than 0.05) in group IA than in group II. In all study patients, neither attack nor scintigraphic perfusion defect appeared on the repeat test after oral administration of nifedipine. In conclusion, multivessel coronary artery spasm simultaneously appears and causes the attack in many patients with variant angina and nearly normal coronary arteriographic findings, and myocardial ischemia due to simultaneous multivessel coronary spasm is likely to be more extensive and severe, persist longer and have a higher frequency of potentially dangerous arrhythmias than that due to spasm of only 1 coronary artery

  9. Growth and characterization of InP/In0.48Ga0.52P quantum dots optimized for single-photon emission

    International Nuclear Information System (INIS)

    In this work the growth of self-assembled InP/InGaP quantum dots, as well as their optical and structural properties are presented and discussed. The QDs were grown on In0.48Ga0.52P, lattice matched to GaAs. Self-assembled InP quantum dots are grown using gas-source molecular beam epitaxy over a wide range of InP deposition rates, using an ultra-low growth rate of about 0.01 atomic monolayers/s, a quantum-dot density of 1 dot/μm2 is realized. The resulting isolated InP quantum dots are individually characterized without the need for lithographical patterning and masks on the substrate. Both excitonic and biexcitonic emissions are observed from single dots, appearing as doublets with a fine-structure splitting of 320 μeV. Hanbury Brown-Twiss correlation measurements for the excitonic emission under cw excitation show anti-bunching behavior with an autocorrelation value of g(2)(0)=0.2. This system is applicable as a single-photon source for applications such as quantum cryptography. The formation of well-ordered chains of InP quantum dots on GaAs (001) substrates by using self-organized In0.48Ga0.52P surface undulations as a template is also demonstrated. The ordering requires neither stacked layers of quantum dots nor substrate misorientation. The structures are investigated by polarization-dependent photoluminescence together with transmission electron microscopy. Luminescence from the In0.48Ga0.52P matrix is polarized in one crystallographic direction due to anisotropic strain arising from a lateral compositional modulation. The photoluminescence measurements show enhanced linear polarization in the alignment direction of quantum dots. A polarization degree of 66% is observed. The optical anisotropy is achieved with a straightforward heterostructure, requiring only a single layer of QDs.

  10. Imaging by single photon emission computed tomography: interest in the pre surgical check up of epilepsy; L'imagerie par tomographie d'emission monophotonique: interet dans le bilan pre-chirurgical de l'epilepsie

    Energy Technology Data Exchange (ETDEWEB)

    Biraben, A. [UPRES EA 2232, Cortex Cerebral et epilepsie, 35 - Rennes (France); Bernard, A.M. [Centre Eugene-Marquis, 35 - Rennes (France)

    1999-12-01

    With the single photon emission computed tomography, it is a more reliable technique that is at someone's disposal, especially to limit spatially the evolution of epilepsy crisis before any surgery act. The determination of the precise area is necessary to make sure that the crisis come really from this area and the determination of the functionality of this area is checked to be sure that the ablation of the zone will not lead to an unacceptable functional deficit. (N.C.)

  11. 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.)

  12. Measurement of temporal regional cerebral perfusion with single-photon emission tomography predicts rate of decline in language function and survival in early Alzheimer's disease

    International Nuclear Information System (INIS)

    We determined the relationship between regional cerebral blood flow (rCBF) measured with single-photon emission tomography (SPET) and decline in cognitive function and survival in Alzheimer's disease. In a prospective follow-up study, 69 consecutively referred patients with early probable Alzheimer's disease (NINCDS/ADRDA criteria) underwent SPET performed at the time of initial diagnosis using technetium-99m-labelled hexamethylpropylene amine oxime. Neuropsychological function was assessed at baseline and after 6 months and survival data were available on all patients, extending to 5.5 years of follow-up. Lower left temporal (P<0.01) and lower left parietal (P<0.01) rCBF were statistically significantly related to decline in language function after 6 months. The association between left temporal rCBF and survival was also statistically significant (P<0.05) using Cox proportional hazards regression analysis. Performing analysis with quartiles of the distribution, we found a threshold effect for low left temporal rCBF (rCBF<73.7%, P<0.01) and high risk of mortality. In this lowest quartile, median survival time was 2.7 years (follow-up to 5.2 years), compared with 4.4 years in the other quartiles (follow-up to 5.5 years). Kaplan-Meier survival curves showed statistically significant (P<0.05, log rank test) survival curves for the lowest versus other quartiles of left temporal rCBF. All results were unaffected by adjustment for age, sex, dementia severity, duration of symptoms, education and ratings of local cortical atrophy. We conclude that left temporal rCBF predicts decline in language function and survival in patients with early probable Alzheimer's disease, with a threshold effect of low rCBF and high risk of mortality. (orig.)

  13. Assessment of prognostic value of semiquantitative parameters on gated single photon emission computed tomography myocardial perfusion scintigraphy in a large middle eastern population

    International Nuclear Information System (INIS)

    Coronary artery disease is the leading cause of mortality worldwide. The goal of this study is to determine the prognostic value of semiquantitative parameters of electrocardiogram-gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a large Middle Eastern (Iranian) population. This study was a prospective study including all patients referred to our center for myocardial perfusion scan. The patients were followed annually up to 24 months and their survival information was collected. From 1148 patients, 473 (41.2%) men and 675 (58.8%) women, 40.6% had normal MPI, 13.3% near normal and 46.1% abnormal MPI. After follow-up of 929 patients, 97.4% of patients were alive, and 2.6% succumbed to cardiac deaths. Abnormal ejection fraction was related with cardiac events (P = 0.001), but neither transient ischemic dilation (TID) (P = 0.09) nor lung/heart ratio (P = 0.92) showed such relationship. Association between summed difference score (SDS) and soft cardiac events (P < 0.001) was significant. Summed motion score (SMS) and summed thickening score (STS) showed a significant relation with hard cardiac events, including myocardial infarction and cardiac death (P < 0.001 and P = 0.001, respectively). Totally, risk of all cardiac events was significantly higher in abnormal MPI group than normal group (P < 0.001, 0.02, and 0.025, respectively). No significant relationship was found between TID and total cardiac events (P = 0.478). Semiquantitative variables derived from gated SPECT MPI have independent prognostic value. Rate of total cardiac events is higher in patients with higher summed stress score and SDS. Total and hard cardiac events are higher in upper scores of functional parameters (SMS and STS). Total cardiac events are higher in patients with lower left ventricular ejection fraction

  14. Analysis of regional cerebral blood flow and distribution volume in Machado-Joseph disease by iodine-123I IMP single photon emission computed tomography

    International Nuclear Information System (INIS)

    Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Its clinical features vary greatly in different generations of the same family. Regional cerebral blood flow (rCBF) and distribution volume (Vd) in the pons, cerebellum, and cerebral cortex were measured in 12 patients with MJD by autoradiography (ARG) and the table look-up (TLU) method of iodine-123 IMP (123I-IMP) single photon emission computed tomography (SPECT). Representative cases were as follows: A 46-year-old woman first experienced gait ataxia at age 38. Computed tomography (CT) and magnetic resonance imaging (MRI) showed no atrophy in the pons or cerebellum, but rCBF measured by the 123I-IMP SPECT ARG method detected hypoperfusion in the pons, and cerebellar vermis and hemisphere. A 76-year-old woman first experienced gait ataxia at age 69. CT and MRI findings showed severe atrophy in the pons, and cerebellar vermis and hemisphere. Moreover, rCBF was decreased in the pons, whereas it was not decreased in the cerebellar vermis and hemisphere. In the pons of patients with MJD, rCBF was markedly decreased regardless of disease severity. Because this SPECT finding for the pons looked like a 'dot', we have called it the 'pontine dot sign'. In the MJD group, rCBF was significantly decreased in the pons (Student's t test, pd was also significantly decreased in the pons (pd for the pons and age at onset (r=0.59, pd in the cerebellar hemispheres and International Cooperative Ataxia Rating Scale (r=0.644, pd obtained by 123I-IMP SPECT for patients with MJD identified by gene analysis. Our study shows that SPECT measurement of rCBF and Vd is useful for understanding the pathophysiology of MJD. (author)

  15. Preliminary application of dynamic pulmonary xenon-133 single-photon emission tomography in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery

    Energy Technology Data Exchange (ETDEWEB)

    Suga, Kazuyoshi; Nishigauchi, Kazuya; Matsunaga, Naofumi; Matsumoto, Tsuneo; Kume, Norihiko [Univ. School of Medicine, Yamaguchi (Japan). Dept. of Radiol.; Sugi, Kazuro; Esato, Kensuke [First Department of Surgery, Yamaguchi University School of Medicine, Ube, Yamaguchi (Japan)

    1998-04-01

    Dynamic pulmonary xenon-133 single-photon emission tomography (SPET) with three-dimensional (3D) displays was preliminarily applied to select resection targets for thoracoscopic lung volume reduction surgery (LVRS) and to assess regional ventilatory changes following surgery. Dynamic SPET was performed using a triple-detector SPET system in 14 patients with pulmonary emphysema before and after LVRS. After reconstructing colour-illuminated, surface-rendered 3D images of equilibrium (EQ) and 3-min washout (WO{sub 3}), a single 3D fusion display was created from these two different time-course image sets, in which the 3D WO{sub 3} image indicating {sup 133}Xe retention was visible through the overlying 3D EQ image delineating lung contours. Volumetric extent of retention on this display was quantified by a {sup 133}Xe retention index, defined as the ratio (%) of total pixel numbers of segmented 3-min WO data to those of EQ data. {sup 133}Xe SPET and appropriately thresholded 3D displays efficiently localized a total of 36 retention sites; 19 (52.7%) of these sites were not localized by CT because they were within the widely or homogeneously spreading non-bullous emphysematous lung tissues. The 3D displays enhanced the perception of anatomical configurations and the extent of {sup 133}Xe retention compared with multislice tomograms. Postoperatively, 3D fusion display visualized the details of regional changes in retention, and changes in the retention index on the 3D display with a standardized threshold correlated well with changes in {sup 133}Xe clearance time (T{sub 1/2}) and %FEV{sub 1} (r = 0.881 and 0.856, respectively; P<0.0001). This preliminary study indicates that {sup 133}Xe SPET and appropriately thresholded, topographic 3D displays are of potential use in selecting resection targets for LVRS, and in evaluating the treatment effects on regional ventilation. (orig.) With 4 figs., 1 tab., 32 refs.

  16. Whole body bone scintigraphy and single photon emission computed tomography/computed tomography (SPECT/CT) as combined nuclear medicine protocol for the initial staging of prostate cancer

    International Nuclear Information System (INIS)

    Full text: The aim of the study was to apply a combined nuclear medicine protocol, including Whole Body Bone Scintigraphy (WBS) and Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) of the pelvis for the initial staging of patients with prostate cancer. We have examined 23 patients with newly diagnosed prostate cancer. the patients were divided in to three risk groups, respectively low risk group (5 patients, 22%), intermediate risk group (6 patients, 26%) and high risk group (12 patients, 52%). Pathological findings detected by WBS were reported in 16 (67%) of the patients. In 7 (30%) of them they were suspicious for metastases.After the SPECT/CT of the pelvis all suspicious foci from the WBS were confirmed to be osteosclerotic metastatic leasons. In addition, the CT scan visualized enlarged regional lymph nodes in 7 patients (30%) and seminal vesicles with altered morphology suspected for infiltration in 5 patients (22%). In four out of 7 patients with enlarged lymph nodes we found simultaneous bone metastases, while in the rest of them the lymphadenopathy was an isolated finding. As a result from the application of the combined nuclear medicine protocol in one of the patients from the low risk group and in one of those with intermediate risk, as well as in six high-risk patients the opportunity for surgery was rejected because of bone metastases and/or regional lymphadenopathy. In the remaining 15 patients, including also those with high risk, decision for radical prostatectomy was made. Our first experience with the application of the combined nuclear medicine protocol, including WBS and SPECT/CT of the pelvis demonstrated that the procedure allows for right initial staging of patients with prostate cancer as well as for choosing an appropriate treatment by performing a one-stop complex imaging examination

  17. Postoperative myocardial infarction documented by technetium pyrophosphate scan using single-photon emission computed tomography: Significance of intraoperative myocardial ischemia and hemodynamic control

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, D.C.; Chung, F.; Burns, R.J.; Houston, P.L.; Feindel, C.M. (Toronto Hospital, Ontario (Canada))

    1989-12-01

    The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 +/- 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative beta-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5 were shown to correlate with increased CPK-MB release (P less than 0.05) and tends to occur more frequently with lateral myocardial infarction.

  18. Preliminary application of dynamic pulmonary xenon-133 single-photon emission tomography in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery

    International Nuclear Information System (INIS)

    Dynamic pulmonary xenon-133 single-photon emission tomography (SPET) with three-dimensional (3D) displays was preliminarily applied to select resection targets for thoracoscopic lung volume reduction surgery (LVRS) and to assess regional ventilatory changes following surgery. Dynamic SPET was performed using a triple-detector SPET system in 14 patients with pulmonary emphysema before and after LVRS. After reconstructing colour-illuminated, surface-rendered 3D images of equilibrium (EQ) and 3-min washout (WO3), a single 3D fusion display was created from these two different time-course image sets, in which the 3D WO3 image indicating 133Xe retention was visible through the overlying 3D EQ image delineating lung contours. Volumetric extent of retention on this display was quantified by a 133Xe retention index, defined as the ratio (%) of total pixel numbers of segmented 3-min WO data to those of EQ data. 133Xe SPET and appropriately thresholded 3D displays efficiently localized a total of 36 retention sites; 19 (52.7%) of these sites were not localized by CT because they were within the widely or homogeneously spreading non-bullous emphysematous lung tissues. The 3D displays enhanced the perception of anatomical configurations and the extent of 133Xe retention compared with multislice tomograms. Postoperatively, 3D fusion display visualized the details of regional changes in retention, and changes in the retention index on the 3D display with a standardized threshold correlated well with changes in 133Xe clearance time (T1/2) and %FEV1 (r = 0.881 and 0.856, respectively; P133Xe SPET and appropriately thresholded, topographic 3D displays are of potential use in selecting resection targets for LVRS, and in evaluating the treatment effects on regional ventilation. (orig.)

  19. Assessment of the arterial input function for estimation of coronary flow reserve by single photon emission computed tomography: comparison of two different approaches

    Energy Technology Data Exchange (ETDEWEB)

    Storto, Giovanni [IRCCS, CROB, Rionero in Vulture (Italy); Soricelli, Andrea [Institute of Diagnostic and Nuclear Development, SDN Foundation, Naples (Italy); Pellegrino, Teresa; Cuocolo, Alberto [Institute of Biostructures and Bioimages, National Council of Research, University Federico II, Department of Biomorphological and Functional Sciences, Naples (Italy); Petretta, Mario [University Federico II, Department of Clinical Medicine, Cardiovascular and Immunological Sciences, Naples (Italy)

    2009-12-15

    Attempts to estimate coronary flow reserve (CFR) with single photon emission computed tomography (SPECT) tracers have been recently made. We compared two different methods for the estimation of CFR by SPECT imaging. Fourteen patients with coronary artery disease underwent dipyridamole {sup 99m}Tc-sestamibi SPECT and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the right pulmonary artery (PA) and left ventricular (LV) chamber, and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. Rest and stress MBF obtained using first transit counts from PA were higher compared to that from LV chamber (rest: 1.05 {+-} 0.38 vs 0.87 {+-} 0.34 counts/pixel per s, respectively, p < 0.01 and stress: 1.34 {+-} 0.45 vs 0.91 {+-} 0.20 counts/pixel per s, respectively, p < 0.05). In the study vessels, CFR by Doppler was 1.39 {+-} 0.42, and SPECT CFR obtained using first transit counts from PA and LV chamber were 1.36 {+-} 0.43 and 1.16 {+-} 0.39, respectively (p across categories NS). A significant relationship between SPECT CFR obtained using first transit counts from PA and CFR by Doppler was found (r = 0.85, p < 0.001). No relationship between SPECT CFR obtained using first transit counts from LV chamber and CFR by intracoronary Doppler was observed (r = 0.43, p = NS). SPECT-estimated CFR obtained using first transit counts from right PA is more accurate and correlates better with the results of intracoronary Doppler than estimated CFR obtained using arterial input function from LV chamber. (orig.)

  20. Clinical studies on thallium-201 myocardial single-photon emission computed tomography in patients with ischemic heart disease. Clinical evaluation using the polar map method

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Naohiko

    1987-06-01

    In order to evaluate briefly the relative 3-dimensional distribution of /sup 201/Tl 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 /sup 201/Tl 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 /sup 201/Tl. The clinical usefulness in determination of infarct size and in diagnosis of myocardial ischemia were evaluated.

  1. Correlative single photon emission computed tomography imaging of [{sup 123}I]altropane binding in the rat model of Parkinson's

    Energy Technology Data Exchange (ETDEWEB)

    Gleave, Jacqueline A. [Department of Pathology and Molecular Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario, L8N 3Z5 (Canada); Farncombe, Troy H.; Saab, Chantal [Department of Nuclear Medicine, Hamilton Health Sciences, Hamilton, Ontario, L8N 3Z5 (Canada); Doering, Laurie C., E-mail: doering@mcmaster.ca [Department of Pathology and Molecular Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario, L8N 3Z5 (Canada)

    2011-07-15

    Introduction: This study used the dopamine transporter (DAT) probe, [{sup 123}I]-2{beta}-carbomethoxy-3{beta}-(4-fluorophenyl)-N-(3-iodo-E-allyl)nortropane ([{sup 123}I]altropane), to assess the DAT levels in the 6-hydroxydopamine rat model of Parkinson's disease. We sought to assess if the right to left [{sup 123}I]altropane striatal ratios correlated with dopamine content in the striatum and substantia nigra and with behavioural outcomes. Methods: [{sup 123}I]altropane images taken pre- and postlesion were acquired before and after the transplantation of neural stem/progenitor cells. The images obtained using [{sup 123}I]altropane and single photon emission computed tomography (SPECT) were compared with specific behavioural tests and the dopamine content assessed by high-performance liquid chromatography. Results: [{sup 123}I]altropane binding correlated with the content of dopamine in the striatum; however, [{sup 123}I]altropane binding did not correlate with the dopamine content in the substantia nigra. There was a significant correlation of altropane ratios with the cylinder test and the postural instability test, but not with amphetamine rotations. The low coefficient of determination (r{sup 2}) for these correlations indicated that [{sup 123}I]altropane SPECT was not a good predictor of behavioural outcomes. Conclusion: Our data reveal that [{sup 123}I]altropane predicts the integrity of the striatal dopamine nerve terminals, but does not predict the integrity of the nigrostriatal system. [{sup 123}I]altropane could be a useful marker to measure dopamine content in cell replacement therapies; however, it would not be able to evaluate outcomes for neuroprotective strategies.

  2. 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 χ2 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.

  3. An effective tool to detect lesions causing unstable angina with multivessel disease. Iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fukuzawa, Shigeru; Inagaki, Masayuki; Morooka, Shigeru; Inoue, Toshihisa; Sugioka, Juji; Ozawa, Shun [Funabashi Municipal Medical Center, Chiba (Japan)

    1996-10-01

    Radiolabeled fatty acids such as iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid (BMIPP) have unique metabolic properties suggesting potential use as myocardial perfusion tracers. The uptakes of BMIPP and thallium 201 were compared using single photon emission computed tomography (SPECT) in 24 patients displaying unstable angina with multivessel disease at a mean of 3.4 days after admission. Coronary angiography was performed within a week. Uptake was considered normal if the activity was greater than 80% of the normal area, mildly reduced if 50% to 79%, and severely reduced if less than 50%. The regional activities in four quadrants in short-axis slices were measured from basal, mid and apical sets. We attempted to identify the causative lesion on dual SPECT imaging. We planned the following management of each patient based on the results of the dual SPECT study. BMIPP activity imaging found 4 segments (1.4%) with severe decrease, 70 (24.3%) with mild decrease, and 214 (74.3%) with normal uptake. In contrast, Tl activity imaging showed normal uptake in 68 of 74 abnormal BMIPP activity segments. Furthermore, all segments with abnormal BMIPP uptake were matched with locations of coronary artery stenosis by coronary angiography. Accordingly, coronary revascularization (percutaneous transluminal coronary angioplasty, coronary artery bypass grafting) was performed based on BMIPP SPECT. Reductions in BMIPP activity were common in patients with unstable angina with multivessel disease. BMIPP SPECT is an excellent tool for detecting the causative lesion in unstable angina. The subsequent intervention could be performed with less risk based on the strategy of dilating the only causative lesion which was detected by the BMIPP SPECT in patients with multivessel disease displaying unstable angina. (author)

  4. Comparative study of dobutamine stress echocardiography and dual single-photon emission computed tomography (Thallium-201 and I-123 BMIPP) for assessing myocardial viability after acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Yasugi, Naoko; Hiroki, Tadayuki [Fukuoka Univ., Chikushino (Japan). Chikushi Hospital; Koyanagi, Samon [National Fukuoka-Higashi Hospital, Koga (Japan). Clinical Research Inst.; Ohzono, Keizaburo; Sakai, Kikuo; Matsumoto, Takahiro; Sako, Shigeki; Homma, Tomoki; Azakami, Shirou [National Kyushu Medical Center, Fukuoka (Japan)

    2002-12-01

    Discordance between the {sup 123}I-labelled 15-iodophenyl-3-R, S-methyl pentadecanoic acid (BMIPP) and {sup 201}Tl findings may indicate myocardial viability (MV). This study compared dobutamine stress echocardiography (DSE) and single-photon emission computed tomography (SPECT) using the dual tracers for assessment of MV and prediction of functional recovery after acute myocardial infarction (AMI). DSE and dual SPECT were studied in 35 patients after AMI, of whom 28 underwent percutaneous coronary intervention in the acute stage. Dual SPECT was performed to compare the defect score of BMIPP and {sup 201}Tl. The left ventricular wall motion score (WMS) was estimated during DSE and 6 months later to assess functional recovery of the infarct area. The rate of agreement of MV between dual SPECT and DSE was 89% (p<0.01), and the sensitivity and specificity of DSE for dual SPECT in MV assessment was 86% and 93%, respectively. The positive and negative predictive values for functional recovery by dual SPECT were 76% and 67%, respectively, and by DSE were 90% and 79%, respectively. Four of 5 patients with positive MV by dual SPECT, but without functional recovery, had residual stenosis of the infarct-related artery. The WMS and defect scores of BMIPP and {sup 201}Tl were significantly smaller in patients with functional recovery than in those without. Assessment of MV using DSE concords with the results of dual SPECT in the early stage of AMI. DSE may have a higher predictive value for long-term functional recovery at the infarct area. However, a finding of positive MV by dual SPECT, without functional recovery, may indicate residual stenosis of the infarct-related artery, although the number of cases was small. Combined assessment by dual SPECT and DSE may be useful for detecting MV and jeopardized myocardium. Furthermore, the results suggest that functional recovery of dysfunctional myocardium may depend on the size of the infarct and risk area. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Bartram, P.; Hanel, B.; Gustafsson, F.; Mortensen, J.; Hesse, B. [Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital (Denmark); Toft, J. [Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital (Denmark)]|[Copenhagen City Heart Study, Epidemiological Research Unit (Denmark); Ali, S. [Dept. of Cardiology, Copenhagen University Hospital (Denmark)

    1998-09-01

    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.) With 1 fig., 26 tabs., 22 refs.

  6. Correlation of uptake patterns on single-photon emission computed tomography/computed tomography (SPECT/CT)and treatment response in patients with knee pain

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Geon; Hwang, Kyung Hoon; Lee, Hae Jin; Kim, Seog Gyun; Lee, Beom Koo [Gachon University Gil Hospital, Incheon (Korea, Republic of)

    2016-06-15

    To determine whether treatment response in patients with knee pain could be predicted using uptake patterns on single-photon emission computed tomography/computed tomography (SPECT/CT) images. Ninety-five patients with knee pain who had undergone SPECT/CT were included in this retrospective study. Subjects were divided into three groups: increased focal uptake (FTU), increased irregular tracer uptake (ITU), and no tracer uptake (NTU). A numeric rating scale (NRS-11) assessed pain intensity. We analyzed the association between uptake patterns and treatment response using Pearson's chi-square test and Fisher's exact test. Uptake was quantified from SPECT/CT with region of interest (ROI) counting, and an intraclass correlation coefficient (ICC) calculated agreement. We used Student' t-test to calculate statistically significant differences of counts between groups and the Pearson correlation to measure the relationship between counts and initial NRS-1k1. Multivariate logistic regression analysis determined which variables were significantly associated with uptake. The FTU group included 32 patients; ITU, 39; and NTU, 24. With conservative management, 64 % of patients with increased tracer uptake (TU, both focal and irregular) and 36 % with NTU showed positive response. Conservative treatment response of FTU was better than NTU, but did not differ from that of ITU. Conservative treatment response of TU was significantly different from that of NTU (OR 3.1; p 0.036). Moderate positive correlation was observed between ITU and initial NRS-11. Age and initial NRS-11 significantly predicted uptake. Patients with uptake in their knee(s) on SPECT/CT showed positive treatment response under conservative treatment.

  7. Anti-3-[18F]FACBC Positron Emission Tomography-Computerized Tomography and 111In-Capromab Pendetide Single Photon Emission Computerized Tomography-Computerized Tomography for Recurrent Prostate Carcinoma: Results of a Prospective Clinical Trial

    Science.gov (United States)

    Schuster, David M.; Nieh, Peter T.; Jani, Ashesh B.; Amzat, Rianot; Bowman, F. DuBois; Halkar, Raghuveer K.; Master, Viraj A.; Nye, Jonathon A.; Odewole, Oluwaseun A.; Osunkoya, Adeboye O.; Savir-Baruch, Bital; Alaei-Taleghani, Pooneh; Goodman, Mark M.

    2014-01-01

    Purpose We prospectively evaluated the amino acid analogue positron emission tomography radiotracer anti-3-[18F]FACBC compared to ProstaScint® (111In-capromab pendetide) single photon emission computerized tomography-computerized tomography to detect recurrent prostate carcinoma. Materials and Methods A total of 93 patients met study inclusion criteria who underwent anti-3-[18F]FACBC positron emission tomography-computerized tomography plus 111In-capromab pendetide single photon emission computerized tomography-computerized tomography for suspected recurrent prostate carcinoma within 90 days. Reference standards were applied by a multidisciplinary board. We calculated diagnostic performance for detecting disease. Results In the 91 of 93 patients with sufficient data for a consensus on the presence or absence of prostate/bed disease anti-3-[18F]FACBC had 90.2% sensitivity, 40.0% specificity, 73.6% accuracy, 75.3% positive predictive value and 66.7% negative predictive value compared to 111In-capromab pendetide with 67.2%, 56.7%, 63.7%, 75.9% and 45.9%, respectively. In the 70 of 93 patients with a consensus on the presence or absence of extraprostatic disease anti-3-[18F]FACBC had 55.0% sensitivity, 96.7% specificity, 72.9% accuracy, 95.7% positive predictive value and 61.7% negative predictive value compared to 111In-capromabpendetide with10.0%, 86.7%, 42.9%, 50.0% and 41.9%, respectively. Of 77 index lesions used to prove positivity histological proof was obtained in 74 (96.1%). Anti-3-[18F]FACBC identified 14 more positive prostate bed recurrences (55 vs 41) and 18 more patients with extraprostatic involvement (22 vs 4). Anti-3-[18F]FACBC positron emission tomography-computerized tomography correctly up-staged 18 of 70 cases (25.7%) in which there was a consensus on the presence or absence of extraprostatic involvement. Conclusions Better diagnostic performance was noted for anti-3-[18F]FACBC positron emission tomography-computerized tomography than for 111In

  8. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with 99mTc-methylene diphosphonate single photon emission computed tomography/computed tomography

    OpenAIRE

    Chakraborty, Partha Sarathi; Karunanithi, Sellam; Dhull, Varun Singh; Kumar, Kunal; Tripathi, Madhavi

    2015-01-01

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. 99mTc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission c...

  9. 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

    OpenAIRE

    Lee, Won Woo; So, Young; Kim, Ki-Bong; Lee, Dong Soo

    2014-01-01

    Objective The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), 201Tl perfusion status at rest, 201Tl 24 hours redistribution and systolic wall thickening of 99mTc-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 by...

  10. Reduced regional cerebral blood flow in aged noninsulin-dependent diabetic patients with no history of cerebrovascular disease: evaluation by N-isopropyl- sup 123 I-p-iodoamphetamine with single-photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wakisaka, M.; Nagamachi, S.; Inoue, K.; Morotomi, Y.; Nunoi, K.; Fujishima, M. (Higashi Hospital, (Japan))

    1990-10-01

    Regional cerebral blood flow was measured using N-isopropyl-{sup 123}I-iodoamphetamine with single-photon emission computed tomography (CT) in 16 aged patients with noninsulin-dependent diabetes mellitus (NIDDM, average age 72.8 years, average fasting plasma glucose 7.7 mmol/L), and 12 nondiabetic subjects (71.6 years, 5.3 mmol/L). None had any history of a cerebrovascular accident. Systolic blood pressure (SBP), total cholesterol, and triglyceride levels did not differ between groups. Areas of hypoperfusion were observed in 14 diabetic patients (12 patients had multiple lesions) and in 6 nondiabetic subjects (3 had multiple lesions). Areas where radioactivity was greater than or equal to 65% of the maximum count of the slice was defined as a region with normal cerebral blood flow (region of interest A, ROI-A), and areas where the count was greater than or equal to 45% were defined as brain tissue regions other than ventricles (ROI-B). The average ROI-A/B ratio of 16 slices was used as a semiquantitative indicator of normal cerebral blood flow throughout the entire brain. Mean ROI-A/B ratio was 49.6 +/- 1.7% in the diabetic group, significantly lower than the 57.9 +/- 1.6% at the nondiabetic group (p less than 0.005). The ratio was inversely correlated with SBP (r = -0.61, p less than 0.05), total cholesterol (r = -0.51, p less than 0.05), and atherogenic index (r = -0.64, p less than 0.01), and was positively correlated with high-density lipoprotein (HDL) cholesterol (r = 0.51, p less than 0.05) in the diabetic, but not the nondiabetic group. These observations suggest that the age-related reduction in cerebral blood flow may be accelerated by a combination of hyperglycemia plus other risk factors for atherosclerosis.

  11. Reduced regional cerebral blood flow in aged noninsulin-dependent diabetic patients with no history of cerebrovascular disease: evaluation by N-isopropyl-123I-p-iodoamphetamine with single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Regional cerebral blood flow was measured using N-isopropyl-123I-iodoamphetamine with single-photon emission computed tomography (CT) in 16 aged patients with noninsulin-dependent diabetes mellitus (NIDDM, average age 72.8 years, average fasting plasma glucose 7.7 mmol/L), and 12 nondiabetic subjects (71.6 years, 5.3 mmol/L). None had any history of a cerebrovascular accident. Systolic blood pressure (SBP), total cholesterol, and triglyceride levels did not differ between groups. Areas of hypoperfusion were observed in 14 diabetic patients (12 patients had multiple lesions) and in 6 nondiabetic subjects (3 had multiple lesions). Areas where radioactivity was greater than or equal to 65% of the maximum count of the slice was defined as a region with normal cerebral blood flow (region of interest A, ROI-A), and areas where the count was greater than or equal to 45% were defined as brain tissue regions other than ventricles (ROI-B). The average ROI-A/B ratio of 16 slices was used as a semiquantitative indicator of normal cerebral blood flow throughout the entire brain. Mean ROI-A/B ratio was 49.6 +/- 1.7% in the diabetic group, significantly lower than the 57.9 +/- 1.6% at the nondiabetic group (p less than 0.005). The ratio was inversely correlated with SBP (r = -0.61, p less than 0.05), total cholesterol (r = -0.51, p less than 0.05), and atherogenic index (r = -0.64, p less than 0.01), and was positively correlated with high-density lipoprotein (HDL) cholesterol (r = 0.51, p less than 0.05) in the diabetic, but not the nondiabetic group. These observations suggest that the age-related reduction in cerebral blood flow may be accelerated by a combination of hyperglycemia plus other risk factors for atherosclerosis

  12. Growth and characterization of InP/In{sub 0.48}Ga{sub 0.52}P quantum dots optimized for single-photon emission

    Energy Technology Data Exchange (ETDEWEB)

    Ugur, Asli

    2012-08-28

    In this work the growth of self-assembled InP/InGaP quantum dots, as well as their optical and structural properties are presented and discussed. The QDs were grown on In{sub 0.48}Ga{sub 0.52}P, lattice matched to GaAs. Self-assembled InP quantum dots are grown using gas-source molecular beam epitaxy over a wide range of InP deposition rates, using an ultra-low growth rate of about 0.01 atomic monolayers/s, a quantum-dot density of 1 dot/μm{sup 2} is realized. The resulting isolated InP quantum dots are individually characterized without the need for lithographical patterning and masks on the substrate. Both excitonic and biexcitonic emissions are observed from single dots, appearing as doublets with a fine-structure splitting of 320 μeV. Hanbury Brown-Twiss correlation measurements for the excitonic emission under cw excitation show anti-bunching behavior with an autocorrelation value of g{sup (2)}(0)=0.2. This system is applicable as a single-photon source for applications such as quantum cryptography. The formation of well-ordered chains of InP quantum dots on GaAs (001) substrates by using self-organized In{sub 0.48}Ga{sub 0.52}P surface undulations as a template is also demonstrated. The ordering requires neither stacked layers of quantum dots nor substrate misorientation. The structures are investigated by polarization-dependent photoluminescence together with transmission electron microscopy. Luminescence from the In{sub 0.48}Ga{sub 0.52}P matrix is polarized in one crystallographic direction due to anisotropic strain arising from a lateral compositional modulation. The photoluminescence measurements show enhanced linear polarization in the alignment direction of quantum dots. A polarization degree of 66% is observed. The optical anisotropy is achieved with a straightforward heterostructure, requiring only a single layer of QDs.

  13. Clinical applications of single photon emission tomography in neuromedicine. Pt. 2. Dementia, psychotic disorders, inflammation, trauma; Klinische Anwendungen der Single-Photon-Emissionstomographie in der Neuromedizin. T. 2. Dementielle Erkrankungen, Psychosen, Entzuendungen, Schaedelhirntrauma

    Energy Technology Data Exchange (ETDEWEB)

    Bartenstein, P.; Gruenwald, F.; Kuwert, T.; Tatsch, K.; Sabri, O.; Benkert, O.; Fahlbusch, R.; Gruender, G.; Herholz, K.; Weiller, C. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    2000-12-01

    This article gives in his second part a critical review of the clinical applications of SPECT with perfusion markers and receptor ligands in dementing disorders and psychosis. In addition this review discusses clinical applications of SPECT investigations with perfusion markers in inflammatory diseases of the central nervous system and in brain trauma. (orig.) [German] Die vorliegende Arbeit vermittelt in ihrem zweiten Teil eine kritisch wertende Uebersicht ueber die klinischen Anwendungsmoeglichkeiten von SPECT-Untersuchungen mit Perfusionsmarkern und Rezeptorliganden bei dementiellen Erkrankungen sowie affektiven und schizophrenen Psychosen. Darueber hinaus werden in dieser Uebersicht Anwendungen von SPECT-Untersuchungen mit Perfusionsmarkern bei Fragestellungen im Rahmen von Entzuendungen des zentralen Nervensystems und bei Schaedelhirntraumata diskutiert. (orig.)

  14. Respective roles of scatter, attenuation, depth-dependent collimator response and finite spatial resolution in cardiac single-photon emission tomography quantitation: a Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    El Fakhri, G.N.; Buvat, I.; Pelegrini, M.; Benali, H.; Todd-Pokropek, A.; Paola, R. di [Institut National de la Sante et de la Recherche Medicale (INSERM), Hopital Necker, 75 - Paris (France); Almeida, P.; Bendriem, B. [SHFJ, Groupe Instrumentation PET/SPET, Orsay (France)

    1999-05-01

    The purpose of this study was to investigate the relative influence of scatter, attenuation, depth-dependent collimator response and finite spatial resolution upon the image characteristics in cardiac single-photon emission tomography (SPET). An acquisition of an anthropomorphic cardiac phantom was performed together with corresponding SPET Monte Carlo simulations. The cardiac phantom and the Monte Carlo simulations were designed so that the effect of scatter, attenuation, depth-dependent collimator response and finite spatial resolution could be studied individually and in combination. The impact of each physical effect and of combinations of effects was studied in terms of absolute and relative quantitative accuracy, spatial resolution and signal-to-noise ratio (SNR) in the resulting images. No corrections for these effects were assessed. Results obtained from Monte Carlo simulations and real acquisitions were in excellent agreement. Attenuation introduced about 90% activity underestimation in a 10-mm-thick left ventricle wall while finite spatial resolution alone introduced about 30% activity underestimation. Scatter had a negligible impact on quantitative accuracy in the recontructed slices when attenuation was present. Neither bull`s eye map homogeneity nor contrast between a hot and a cold region were affected by depth-dependent collimator response or finite spatial resolution. Bull`s eye map homogeneity was severely affected by attenuation but not by scatter. Attenuation and scatter reduced contrast by about 20% each. Both attenuation and scatter increased the full-width at half-maximum (FWHM) characterizing the spatial resolution of the imaging system by {approx}1 mm each but the main effect responsible for the observed 11-mm FWHM spatial resolution was the depth-dependent collimator response. SNR was reduced by a factor of {approx}2.5 because of attenuation, while scattered counts increased SNR by {approx}10%. In conclusion, the quantification of the

  15. 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. κ 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

  16. Semi-quantitative ventilation/perfusion scintigraphy and single-photon emission tomography for evaluation of lung volume reduction surgery candidates: description and prediction of clinical outcome

    International Nuclear Information System (INIS)

    Ventilation/perfusion scans with single-photon emission tomography (SPET) were reviewed to determine their usefulness in the evaluation of lung volume reduction surgery (LVRS) candidates, and as a predictor of outcome after surgery. Fifty consecutive planar ventilation (99mTc-DTPA aerosol) and perfusion (99mTc-MAA) scans with perfusion SPET of patients evaluated for LVRS were retrospectively reviewed. Technical quality and the severity and extent of radiotracer defects in the upper and lower halves of the lungs were scored from visual inspection of planar scans and SPET data separately. An emphysema index (EI) (extent x severity) for the upper and lower halves of the lung, and an EI ratio for upper to lower lung were calculated for both planar and SPET scans. The ratios were compared with post-LVRS outcomes, 3, 6 and 12 months after surgery. All perfusion and SPET images were technically adequate. Forty-six percent of ventilation scans were not technically adequate due to central airway tracer deposition. Severity, extent, EI scores and EI ratios between perfusion and SPET were in good agreement (r = 0.52-0.68). The mean perfusion EI ratio was significantly different between the 30 patients undergoing biapical LVRS and the 17 patients excluded from LVRS (3.3±1.8 versus 1.2±0.7; P1 at 3 months (r = 0.37, P = 0.04), 6 months (r = 0.36, P = 0.05), and 12 months (r = 0.42, P = 0.03), and the transition dyspnea index at 6 months (r = 0.48, P = 0.014) after LVRS. It is concluded that patients selected to undergo LVRS have more severe and extensive apical perfusion deficits than patients not selected for LVRS, based on CT determination. SPET after aerosol V/Q imaging does not add significantly to planar perfusion scans. Aerosol DTPA ventilation scans are not consistently useful. Perfusion lung scanning may be useful in selecting patients with successful outcomes after LVRS. (orig.)

  17. 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

  18. Semi-quantitative ventilation/perfusion scintigraphy and single-photon emission tomography for evaluation of lung volume reduction surgery candidates: description and prediction of clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Jamadar, D.A.; Kazerooni, E.A. [Department of Radiology, University of Michigan Medical Center, Ann Arbor (United States); Martinez, F.J. [Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor (United States); Wahl, R.L. [Department of Radiology, University of Michigan Medical Center, Ann Arbor (United States)]|[Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor (United States)

    1999-07-01

    Ventilation/perfusion scans with single-photon emission tomography (SPET) were reviewed to determine their usefulness in the evaluation of lung volume reduction surgery (LVRS) candidates, and as a predictor of outcome after surgery. Fifty consecutive planar ventilation ({sup 99m}Tc-DTPA aerosol) and perfusion ({sup 99m}Tc-MAA) scans with perfusion SPET of patients evaluated for LVRS were retrospectively reviewed. Technical quality and the severity and extent of radiotracer defects in the upper and lower halves of the lungs were scored from visual inspection of planar scans and SPET data separately. An emphysema index (EI) (extent x severity) for the upper and lower halves of the lung, and an EI ratio for upper to lower lung were calculated for both planar and SPET scans. The ratios were compared with post-LVRS outcomes, 3, 6 and 12 months after surgery. All perfusion and SPET images were technically adequate. Forty-six percent of ventilation scans were not technically adequate due to central airway tracer deposition. Severity, extent, EI scores and EI ratios between perfusion and SPET were in good agreement (r = 0.52-0.68). The mean perfusion EI ratio was significantly different between the 30 patients undergoing biapical LVRS and the 17 patients excluded from LVRS (3.3{+-}1.8 versus 1.2{+-}0.7; P<0.0001), in keeping with the anatomic distribution of emphysema by which patients were selected for surgery by computed tomography (CT). The perfusion EI ratio correlated moderately with the change in FEV{sub 1} at 3 months (r = 0.37, P = 0.04), 6 months (r = 0.36, P = 0.05), and 12 months (r = 0.42, P = 0.03), and the transition dyspnea index at 6 months (r = 0.48, P = 0.014) after LVRS. It is concluded that patients selected to undergo LVRS have more severe and extensive apical perfusion deficits than patients not selected for LVRS, based on CT determination. SPET after aerosol V/Q imaging does not add significantly to planar perfusion scans. Aerosol DTPA ventilation

  19. Prediction of traumatic avascular necrosis of the femoral head by single photon emission computerized tomography and computerized tomography: an experimental study in dogs

    Institute of Scientific and Technical Information of China (English)

    SHEN Feng; YAN Zuo-qin; GUO Chang-an; SHI Hong-cheng; GU Yu-shen; ZENG Meng-su; LU Xiao-yu; LIU Jun

    2011-01-01

    Objective: To evaluate the femoral head perfusion and to predict the traumatic avascular necrosis (AVN) of the femoral head by single photon emission computerized tomography and computerized tomography (SPECT/CT). Methods: Totally 18 adult beagle dogs were divided randomly into three equal-sized (n=6) groups. Subsequently different degrees of ischemia model were developed by destroying blood vessels of the femoral head. The left hip received sham operation as normal control and the right hip underwent blood interruption. In Group A, the ligamentum teres was cut off. In Group B, the marrow cavity of the right femoral neck was destroyed while in Group C, the soft tissues at the base of the femoral neck were stripped in addition to the resection of the ligamentum teres and destruction of the marrow cavity. Three hours after surgery, SPECT/ CT was performed. Laser Doppler Flowmetry (LDF) measurements were also obtained at three different time points (before operation, immediately and three hours after operation) in order to assess the change process of blood supply to the femoral head. Results: SPECT/CT showed no significant difference in the radionuclide uptake between the right and left femoral heads in Group A (t=-0.09, P=0.94) and Group B (t= 0.52, P=0.62). However, in Group C, it was 261 ±62 for the right femoral head, only 12% of that in the left femoral head. LDF measurements indicated that the femoral head perfusion was decreased from (45.0±3.3) PU to (39.1±3.7) PU in Group A, from (44.0±2.7) PU to (34.3±2.6) PU in Group B, and from (47.3 ±2.1) PU to (4.96±0.6) PU in Group C immediately after operation. However, the perfusion was restored and returned to normal values three hours after operation except in Group C. Conclusion: SPECT/CT could assess the perfusion of the femoral head semiquantitatively, which might be useful in predicting the development of traumatic AVN.

  20. In vivo evaluation in mice and metabolism in blood of human volunteers of [123I]iodo-PK11195: a possible single-photon emission tomography tracer for visualization of inflammation

    International Nuclear Information System (INIS)

    We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brain and heart) in mice and the metabolism in blood of human volunteers of iodine-123 labelled 1-(2-iodophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinoline carboxamide ([123I]iodo-PK11195), a potential radioligand for visualization of inflammation in humans by single-photon emission tomography. In three series of 18 white mice (NMRI, 20-25 g), the concentration of radioactivity was measured during 48 h. Blood samples were taken, organs and intestines were excised, excretion was collected and all tissues were weighed and counted for radioactivity. The tissue uptake of radioactivity was measured as % of the injected activity/g of tissue. The excretion was expressed as % of the injected activity. Selective tissue uptake was investigated by pretreatment of another three series of 18 mice with cold PK11195 (1 mg/kg body weight). There was an inflow of [123I]iodo-PK11195 in the brain and among peripheral organs, heart (42.3%), lungs (133.5%) and kidneys (18.4%) had the highest uptake. After pretreatment with cold PK11195, there was a decrease in accumulation in the latter three organs, especially in heart (ca. 55%) and lungs (ca. 80%). Metabolite analysis was performed using high-performance liquid chromatography (HPLC). First, the extraction yield of [123I]iodo-PK11195 from blood and tissue was assessed, and found to be >90%. From blank blood samples and organs spiked with [123I]iodo-PK11195 it was concluded that no metabolization took place during the extraction procedure. Analysis of plasma, brain and heart of mice showed that 10 min p.i. [123I]iodo-PK11195 was the only significant (ca. 95%) radioactive compound in brain and heart where-as in plasma other radioactive products (>60%) appeared. Analysis of plasma samples of the three human volunteers at 7, 20, 37 and 50 min p.i. showed that [123I]iodo-PK11195 rapidly decomposes into two polar metabolites, which at these time

  1. In vivo evaluation in mice and metabolism in blood of human volunteers of [{sup 123}I]iodo-PK11195: a possible single-photon emission tomography tracer for visualization of inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Dumont, F.; Vos, F. de; Slegers, G. [Department of Radiopharmacy, Univ. of Gent (Belgium); Versijpt, J. [Division of Nuclear Medicine, University Hospital Gent (Belgium)]|[Department of Biological Psychiatry, University Hospital Groningen (Netherlands); Jansen, H.M.L.; Dierckx, R.A. [Division of Nuclear Medicine, University Hospital Gent (Belgium); Korf, J. [Department of Biological Psychiatry, University Hospital Groningen (Netherlands)

    1999-03-01

    We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brain and heart) in mice and the metabolism in blood of human volunteers of iodine-123 labelled 1-(2-iodophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinoline carboxamide ([{sup 123}I]iodo-PK11195), a potential radioligand for visualization of inflammation in humans by single-photon emission tomography. In three series of 18 white mice (NMRI, 20-25 g), the concentration of radioactivity was measured during 48 h. Blood samples were taken, organs and intestines were excised, excretion was collected and all tissues were weighed and counted for radioactivity. The tissue uptake of radioactivity was measured as % of the injected activity/g of tissue. The excretion was expressed as % of the injected activity. Selective tissue uptake was investigated by pretreatment of another three series of 18 mice with cold PK11195 (1 mg/kg body weight). There was an inflow of [{sup 123}I]iodo-PK11195 in the brain and among peripheral organs, heart (42.3%), lungs (133.5%) and kidneys (18.4%) had the highest uptake. After pretreatment with cold PK11195, there was a decrease in accumulation in the latter three organs, especially in heart (ca. 55%) and lungs (ca. 80%). Metabolite analysis was performed using high-performance liquid chromatography (HPLC). First, the extraction yield of [{sup 123}I]iodo-PK11195 from blood and tissue was assessed, and found to be >90%. From blank blood samples and organs spiked with [{sup 123}I]iodo-PK11195 it was concluded that no metabolization took place during the extraction procedure. Analysis of plasma, brain and heart of mice showed that 10 min p.i. [{sup 123}I]iodo-PK11195 was the only significant (ca. 95%) radioactive compound in brain and heart where-as in plasma other radioactive products (>60%) appeared. Analysis of plasma samples of the three human volunteers at 7, 20, 37 and 50 min p.i. showed that [{sup 123}I]iodo-PK11195 rapidly decomposes into two polar

  2. Microscopic theory of indistinguishable single-photon emission from a quantum dot coupled to a cavity: The role of non-Markovian phonon-induced decoherence

    OpenAIRE

    Nielsen, Per Kær; Lodahl, Peter; Jauho, Antti-Pekka; Mørk, Jesper

    2013-01-01

    We study the fundamental limit on single-photon indistinguishability imposed by decoherence due to phonon interactions in semiconductor quantum dot-cavity quantum electrodynamics systems. Employing an exact diagonalization approach we find large differences compared to standard methods. An important finding is that short-time non-Markovian effects limit the maximal attainable indistinguishability. The results are explained using a polariton picture that yields valuable insight into the phonon...

  3. 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.

  4. 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.

  5. 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...

  6. Analysis of regional cerebral blood flow and distribution volume in Machado-Joseph disease by iodine-{sup 123}I IMP single photon emission computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Tsunemi; Nakajima, Takashi; Fukuhara, Nobuyoshi [National Saigata Hospital, Ohagata, Niigata (Japan)

    2001-09-01

    Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia. Its clinical features vary greatly in different generations of the same family. Regional cerebral blood flow (rCBF) and distribution volume (V{sub d}) in the pons, cerebellum, and cerebral cortex were measured in 12 patients with MJD by autoradiography (ARG) and the table look-up (TLU) method of iodine-123 IMP ({sup 123}I-IMP) single photon emission computed tomography (SPECT). Representative cases were as follows: A 46-year-old woman first experienced gait ataxia at age 38. Computed tomography (CT) and magnetic resonance imaging (MRI) showed no atrophy in the pons or cerebellum, but rCBF measured by the {sup 123}I-IMP SPECT ARG method detected hypoperfusion in the pons, and cerebellar vermis and hemisphere. A 76-year-old woman first experienced gait ataxia at age 69. CT and MRI findings showed severe atrophy in the pons, and cerebellar vermis and hemisphere. Moreover, rCBF was decreased in the pons, whereas it was not decreased in the cerebellar vermis and hemisphere. In the pons of patients with MJD, rCBF was markedly decreased regardless of disease severity. Because this SPECT finding for the pons looked like a 'dot', we have called it the 'pontine dot sign'. In the MJD group, rCBF was significantly decreased in the pons (Student's t test, p<0.01) and cerebellar vermis (p<0.05). The V{sub d} was also significantly decreased in the pons (p<0.005) in comparison with that for normal subjects. Pearson's correlation analysis yielded a significant relationship between the rCBF in the pons and age at onset (r=0.578, p<0.05). There was a strong correlation between the V{sub d} for the pons and age at onset (r=0.59, p<0.05). Person's correlation analysis also showed a significant relationship between the V{sub d} in the cerebellar hemispheres and International Cooperative Ataxia Rating Scale (r=0.644, p<0.05). The pontine rCBFs in patients with early onset MJD

  7. Spontaneous and light-induced photon emission from intact brains of chick embryos

    Institute of Scientific and Technical Information of China (English)

    张锦珠; 于文斗; 孙彤

    1997-01-01

    Photon emission (PE) and light-induced photon emission(LPE) of intact brains isolated from chick embryos have been measured by using the single photon counting device. Experimental results showed that the intensi-ty level of photon emission was detected to be higher from intact brain than from the medium in which the brain was immerged during measuring, and the emission intensity was related to the developmental stages, the healthy situation of the measured embryos, and the freshness of isolated brains as well. After white light illumination, a short-life de-layed emission from intact brains was observed, and its relaxation behavior followed a hyperbolic rather than an expo-nential law. According to the hypothesis of biophoton emission originating from a delocalized coherent electromagnetic field and Frohlich’s idea of coherent long-range interactions in biological systems, discussions were made on the signifi-cance of photon emission in studying cell communication, biological regulation, living system’

  8. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with 99mTc-methylene diphosphonate single photon emission computed tomography/computed tomography

    International Nuclear Information System (INIS)

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. 99mTc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis

  9. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with (99m)Tc-methylene diphosphonate single photon emission computed tomography/computed tomography.

    Science.gov (United States)

    Chakraborty, Partha Sarathi; Karunanithi, Sellam; Dhull, Varun Singh; Kumar, Kunal; Tripathi, Madhavi

    2015-01-01

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. (99m)Tc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis.

  10. Combination of Single-Photon Emission Computed Tomography and Magnetic Resonance Imaging to Track ¹¹¹In-Oxine-Labeled Human Mesenchymal Stem Cells in Neuroblastoma-Bearing Mice

    OpenAIRE

    Cussó, Lorena; Mirones, Isabel; Peña-Zalbidea, Santiago; García-Vázquez, Verónica; García-Castro, Javier; Desco, Manuel

    2014-01-01

    Homing is an inherent, complex, multistep process performed by cells such as human bone marrow mesenchymal stem cells (hMSCs) to travel from a distant location to inflamed or damaged tissue and tumors. This ability of hMSCs has been exploited as a tumor-targeting strategy in cell-based cancer therapy. The purpose of this study was to investigate the applicability of ¹¹¹In-oxine for tracking hMSCs in vivo by combining single-photon emission computed tomography (SPECT) and magnetic resonance im...

  11. Hologram of a single photon

    Science.gov (United States)

    Chrapkiewicz, Radosław; Jachura, Michał; Banaszek, Konrad; Wasilewski, Wojciech

    2016-09-01

    The spatial structure of single photons is becoming an extensively explored resource to facilitate free-space quantum communication and quantum computation as well as for benchmarking the limits of quantum entanglement generation with orbital angular momentum modes or reduction of the photon free-space propagation speed. Although accurate tailoring of the spatial structure of photons is now routinely performed using methods employed for shaping classical optical beams, the reciprocal problem of retrieving the spatial phase-amplitude structure of an unknown single photon cannot be solved using complementary classical holography techniques that are known for excellent interferometric precision. Here, we introduce a method to record a hologram of a single photon that is probed by another reference photon, on the basis of a different concept of the quantum interference between two-photon probability amplitudes. As for classical holograms, the hologram of a single photon encodes the full information about the photon's ‘shape’ (that is, its quantum wavefunction) whose local amplitude and phase are retrieved in the demonstrated experiment.

  12. All-optical tailoring of single-photon spectra in a quantum-dot microcavity system

    CERN Document Server

    Breddermann, Dominik; Binder, Rolf; Zrenner, Artur; Schumacher, Stefan

    2016-01-01

    Semiconductor quantum-dot cavity systems are promising sources for solid-state based on-demand generation of single photons for quantum communication. Commonly, the spectral characteristics of the emitted single photon are fixed by system properties such as electronic transition energies and spectral properties of the cavity. In the present work we study single-photon generation from the quantum-dot biexciton through a partly stimulated non-degenerate two-photon emission. We show that frequency and linewidth of the single photon can be fully controlled by the stimulating laser pulse, ultimately allowing for efficient all-optical spectral shaping of the single photon.

  13. Metal-organic vapor-phase epitaxy-grown ultra-low density InGaAs/GaAs quantum dots exhibiting cascaded single-photon emission at 1.3 μm

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Matthias, E-mail: m.paul@ihfg.uni-stuttgart.de; Kettler, Jan; Zeuner, Katharina; Clausen, Caterina; Jetter, Michael; Michler, Peter [Institut für Halbleiteroptik und Funktionelle Grenzflächen, University of Stuttgart, Allmandring 3, 70569 Stuttgart (Germany)

    2015-03-23

    By metal-organic vapor-phase epitaxy, we have fabricated InGaAs quantum dots on GaAs substrate with an ultra-low lateral density (<10{sup 7} cm{sup −2}). The photoluminescence emission from the quantum dots is shifted to the telecom O-band at 1.31 μm by an InGaAs strain reducing layer. In time-resolved measurements, we find fast decay times for exciton (∼600 ps) and biexciton (∼300 ps). We demonstrate triggered single-photon emission (g{sup (2)}(0)=0.08) as well as cascaded emission from the biexciton decay. Our results suggest that these quantum dots can compete with their counterparts grown by state-of-the-art molecular beam epitaxy.

  14. 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.

  15. High brightness single photon sources based on photonic wires

    DEFF Research Database (Denmark)

    Claudon, J.; Bleuse, J.; Bazin, M.;

    2009-01-01

    We present a novel single-photon-source based on the emission of a semiconductor quantum dot embedded in a single-mode photonic wire. This geometry ensures a very large coupling (> 95%) of the spontaneous emission to the guided mode. Numerical simulations show that a photon collection efficiency as...

  16. Diffusion-weighted magnetic resonance imaging with short T1 inversion recovery-echo planar imaging combined with dual-head coincidence single photon emission computed tomography for diagnosing solitary pulmonary nodule

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; XU Jin-zhi; ZHANG Tong; SHEN Bao-zhong

    2010-01-01

    @@ Positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) has not been widely used in China for expensive cost ($1200). Dual-head coincidence single photon emission computed tomography (DHC-SPECT) can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost ($300 in China) than other imaging examination.

  17. Dual ectopic thyroid in the presence of atrophic orthotopic thyroid gland in a patient with acquired hypothyroidism: Evaluation with hybrid Single-Photon Emission Computed Tomography/Computed Tomography

    International Nuclear Information System (INIS)

    Ectopic thyroid tissue (ETT) refers to all cases in which the thyroid gland is present at a location other than its usual site. The prevalence of ETT is approximately one per 100,000 to 300,000 persons and is reported to occur in one in 4,000 to 8,000 patients with thyroid disease. Multiple ectopia of thyroid is extremely rare. Multiple ectopia in the presence of orthotopic thyroid gland is extremely rare. We report a 13-year-old boy with stunted growth and developmental delay caused due to acquired hypothyroidism. Technetium scan performed as per management protocol identified dual ectopia of thyroid. The role of hybrid Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) in the localization of the sites of ETT is also highlighted

  18. The use of technetium-99m hexamethylpropylene amine oxime labelled granulocytes with single-photon emission tomography imaging in the detection and follow-up of recurrence of infective endocarditis complicating transvenous endocardial pacemaker

    Energy Technology Data Exchange (ETDEWEB)

    Ramackers, J.M. [Department of Nuclear Medicine, CHU E. Herriot, Lyon (France); Kotzki, P.O. [Department of Nuclear Medicine, CHU Lapeyronie et A. de Villeneuve, Montpellier (France); Couret, I. [Department of Nuclear Medicine, CHU Lapeyronie et A. de Villeneuve, Montpellier (France); Messner-Pellenc, P. [Department of Cardiology, CHU Lapeyronie et A. Villeneuve, Montpellier (France); Davy, J.M. [Department of Cardiology, CHU Lapeyronie et A. Villeneuve, Montpellier (France); Rossi, M. [Department of Nuclear Medicine, CHU Lapeyronie et A. de Villeneuve, Montpellier (France)

    1995-11-01

    In this case report we present a patient with a recurrence of subacute bacterial infectious endocarditis (IE) complicating a transvenous endocardial pacemaker. Technetium-99m hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) labelled granulocytes were used for diagnosis and follow-up under medical treatment only, since surgical removal of the pacemaker lead was ruled out because of the general condition of the patient. Single-photon emission tomography (SPET) imaging displayed the active lesion previously suspected on echography. At the end of antibiotic therapy, SPET indicated a favourable disease outcome whereas echocardiographic abnormalities remained nearly unchanged. The medical treatment had eradicated the IE, and the patient did well for more than 1 year thereafter. (orig.)

  19. All-optical tailoring of single-photon spectra in a quantum-dot microcavity system

    OpenAIRE

    Breddermann, Dominik; Heinze, Dirk; Binder, Rolf; Zrenner, Artur; Schumacher, Stefan

    2016-01-01

    Semiconductor quantum-dot cavity systems are promising sources for solid-state based on-demand generation of single photons for quantum communication. Commonly, the spectral characteristics of the emitted single photon are fixed by system properties such as electronic transition energies and spectral properties of the cavity. In the present work we study single-photon generation from the quantum-dot biexciton through a partly stimulated non-degenerate two-photon emission. We show that frequen...

  20. Characterizing heralded single-photon sources with imperfect measurement devices

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, M; Soellner, I; Bocquillon, E; Couteau, C; Laflamme, R; Weihs, G [Institute for Quantum Computing, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1 (Canada)], E-mail: mrazavi@iqc.ca

    2009-06-14

    Any characterization of a single-photon source is not complete without specifying its second-order degree of coherence, i.e., its g{sup (2)} function. An accurate measurement of such coherence functions commonly requires high-precision single-photon detectors, in whose absence only time-averaged measurements are possible. It is not clear, however, how the resulting time-averaged quantities can be used to properly characterize the source. In this paper, we investigate this issue for a heralded source of single photons that relies on continuous-wave parametric down-conversion. By accounting for major shortcomings of the source and the detectors-i.e., the multiple-photon emissions of the source, the time resolution of photodetectors and our chosen width of coincidence window-our theory enables us to infer the true source properties from imperfect measurements. Our theoretical results are corroborated by an experimental demonstration using a PPKTP crystal pumped by a blue laser that results in a single-photon generation rate about 1.2 millions per second per milliwatt of pump power. This work takes an important step towards the standardization of such heralded single-photon sources.

  1. Photonic wires and trumpets for ultrabright single photon sources

    DEFF Research Database (Denmark)

    Gérard, Jean-Michel; Claudon, Julien; Bleuse, Joël;

    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....

  2. The Single-Photon Router

    CERN Document Server

    Hoi, Io-Chun; Johansson, Göran; Palomaki, Tauno; Peropadre, Borja; Delsing, Per

    2011-01-01

    We have embedded an artificial atom, a superconducting "transmon" qubit, in an open transmission line and investigated the strong scattering of incident microwave photons ($\\sim6$ GHz). When an input coherent state, with an average photon number $N\\ll1$ is on resonance with the artificial atom, we observe extinction of up to 90% in the forward propagating field. We use two-tone spectroscopy to study scattering from excited states and we observe electromagnetically induced transparency (EIT). We then use EIT to make a single-photon router, where we can control to what output port an incoming signal is delivered. The maximum on-off ratio is around 90% with a rise and fall time on the order of nanoseconds, consistent with theoretical expectations. The router can easily be extended to have multiple output ports and it can be viewed as a rudimentary quantum node, an important step towards building quantum information networks.

  3. 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...

  4. Limits on the deterministic creation of pure single-photon states using parametric down-conversion

    CERN Document Server

    Christ, Andreas

    2011-01-01

    Parametric down-conversion (PDC) is one of the most widely used methods to create pure single-photon states for quantum information applications. However little attention has been paid to higher-order photon components in the PDC process, yet these ultimately limit the prospects of generating single-photons of high quality. In this paper we investigate the impacts of higher-order photon components and multiple frequency modes on the heralding rates and single-photon fidelities. This enables us to determine the limits of PDC sources for single-photon generation. Our results show that a perfectly single-mode PDC source in conjunction with a photon-number resolving detector is ultimately capable of creating single-photon Fock states with unit fidelity and a maximal state creation probability of 25%. Hence an array of 17 switched sources is required to build a deterministic (>99% emission probability) pure single-photon source.

  5. Very Efficient Single-Photon Sources Based on Quantum Dots in Photonic Wires

    DEFF Research Database (Denmark)

    Gerard, Jean-Michel; Claudon, Julien; Bleuse, Joel;

    2014-01-01

    We review the recent development of high efficiency single photon sources based on a single quantum dot in a photonic wire. Unlike cavity-based devices, very pure single photon emission and efficiencies exceeding 0.7 photon per pulse are jointly demonstrated under non-resonant pumping conditions...... optical properties of "one-dimensional atoms"....

  6. Radioiodinated benzimidazole derivatives as single photon emission computed tomography probes for imaging of {beta}-amyloid plaques in Alzheimer's disease

    Energy Technology Data Exchange (ETDEWEB)

    Cui Mengchao [Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Ono, Masahiro, E-mail: ono@pharm.kyoto-u.ac.j [Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Kimura, Hiroyuki; Kawashima, Hidekazu [Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan); Liu Boli [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Saji, Hideo, E-mail: hsaji@pharm.kyoto-u.ac.j [Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501 (Japan)

    2011-04-15

    Five iodinated 2-phenyl-1H-benzo[d]imidazole derivatives were synthesized and evaluated as potential probes for {beta}-amyloid (A{beta}) plaques. One of the compounds, 4-(6-iodo-1H-benzo[d]imidazol-2-yl)-N,N-dimethylaniline (12), showed excellent affinity for A{beta}{sub 1-42} aggregates (K{sub i}=9.8 nM). Autoradiography with sections of postmortem Alzheimer's disease (AD) brain revealed that a radioiodinated probe [{sup 125}I]12, labeled A{beta} plaques selectively with low nonspecific binding. Biodistribution experiments with normal mice injected intravenously with [{sup 125}I]12 showed high uptake [4.14 percent injected dose per gram (% ID/g) at 2 min] into and rapid clearance (0.15% ID/g at 60 min) from the brain, which may bring about a good signal-to-noise ratio and therefore achieve highly sensitive detection of A{beta} plaques. In addition, [{sup 125}I]12 labeled amyloid plaques in vivo in an AD transgenic model. The preliminary results strongly suggest that [{sup 125}I]12 bears characteristics suitable for detecting amyloid plaques in vivo. When labeled with {sup 123}I, it may be a useful SPECT imaging agent for A{beta} plaques in the brain of living AD patients.

  7. Hiding Single Photons With Spread Spectrum Technology

    CERN Document Server

    Belthangady, Chinmay; 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.

  8. Image reconstruction of single photon emission computed tomography (SPECT) on a pebble bed reactor (PBR) using expectation maximization and exact inversion algorithms: Comparison study by means of numerical phantom

    Science.gov (United States)

    Razali, Azhani Mohd; Abdullah, Jaafar

    2015-04-01

    Single Photon Emission Computed Tomography (SPECT) is a well-known imaging technique used in medical application, and it is part of medical imaging modalities that made the diagnosis and treatment of disease possible. However, SPECT technique is not only limited to the medical sector. Many works are carried out to adapt the same concept by using high-energy photon emission to diagnose process malfunctions in critical industrial systems such as in chemical reaction engineering research laboratories, as well as in oil and gas, petrochemical and petrochemical refining industries. Motivated by vast applications of SPECT technique, this work attempts to study the application of SPECT on a Pebble Bed Reactor (PBR) using numerical phantom of pebbles inside the PBR core. From the cross-sectional images obtained from SPECT, the behavior of pebbles inside the core can be analyzed for further improvement of the PBR design. As the quality of the reconstructed image is largely dependent on the algorithm used, this work aims to compare two image reconstruction algorithms for SPECT, namely the Expectation Maximization Algorithm and the Exact Inversion Formula. The results obtained from the Exact Inversion Formula showed better image contrast and sharpness, and shorter computational time compared to the Expectation Maximization Algorithm.

  9. Validation of the Gate simulation platform in single photon emission computed tomography and application to the development of a complete 3-dimensional reconstruction algorithm

    International Nuclear Information System (INIS)

    Monte Carlo simulations are currently considered in nuclear medical imaging as a powerful tool to design and optimize detection systems, and also to assess reconstruction algorithms and correction methods for degrading physical effects. Among the many simulators available, none of them is considered as a standard in nuclear medical imaging: this fact has motivated the development of a new generic Monte Carlo simulation platform (GATE), based on GEANT4 and dedicated to SPECT/PET (single photo emission computed tomography / positron emission tomography) applications. We participated during this thesis to the development of the GATE platform within an international collaboration. GATE was validated in SPECT by modeling two gamma cameras characterized by a different geometry, one dedicated to small animal imaging and the other used in a clinical context (Philips AXIS), and by comparing the results obtained with GATE simulations with experimental data. The simulation results reproduce accurately the measured performances of both gamma cameras. The GATE platform was then used to develop a new 3-dimensional reconstruction method: F3DMC (fully 3-dimension Monte-Carlo) which consists in computing with Monte Carlo simulation the transition matrix used in an iterative reconstruction algorithm (in this case, ML-EM), including within the transition matrix the main physical effects degrading the image formation process. The results obtained with the F3DMC method were compared to the results obtained with three other more conventional methods (FBP, MLEM, MLEMC) for different phantoms. The results of this study show that F3DMC allows to improve the reconstruction efficiency, the spatial resolution and the signal to noise ratio with a satisfactory quantification of the images. These results should be confirmed by performing clinical experiments and open the door to a unified reconstruction method, which could be applied in SPECT but also in PET. (author)

  10. Localised excitation of a single photon source by a nanowaveguide

    Science.gov (United States)

    Geng, Wei; Manceau, Mathieu; Rahbany, Nancy; Sallet, Vincent; de Vittorio, Massimo; Carbone, Luigi; Glorieux, Quentin; Bramati, Alberto; Couteau, Christophe

    2016-01-01

    Nowadays, integrated photonics is a key technology in quantum information processing (QIP) but achieving all-optical buses for quantum networks with efficient integration of single photon emitters remains a challenge. Photonic crystals and cavities are good candidates but do not tackle how to effectively address a nanoscale emitter. Using a nanowire nanowaveguide, we realise an hybrid nanodevice which locally excites a single photon source (SPS). The nanowire acts as a passive or active sub-wavelength waveguide to excite the quantum emitter. Our results show that localised excitation of a SPS is possible and is compared with free-space excitation. Our proof of principle experiment presents an absolute addressing efficiency ηa ~ 10-4 only ~50% lower than the one using free-space optics. This important step demonstrates that sufficient guided light in a nanowaveguide made of a semiconductor nanowire is achievable to excite a single photon source. We accomplish a hybrid system offering great potentials for electrically driven SPSs and efficient single photon collection and detection, opening the way for optimum absorption/emission of nanoscale emitters. We also discuss how to improve the addressing efficiency of a dipolar nanoscale emitter with our system.

  11. Radiolabeled cyclic arginine-glycine-aspartic (RGD)-conjugated iron oxide nanoparticles as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Shengming; Zhang, Wei; Zhang, Bin, E-mail: zbnuclmd@126.com [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China); Hong, Ruoyu [Soochow University, College of Chemistry, Chemical Engineering and Materials Science & Key Laboratory of Organic Synthesis of Jiangsu Province (China); Chen, Qing; Dong, Jiajia [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China); Chen, Yinyiin [The First Affiliated Hospital of Soochow University, Department of Radiology (China); Chen, Zhiqiang; Wu, Yiwei, E-mail: wuyiwei3988@gmail.com [The First Affiliated Hospital of Soochow University, Department of Nuclear Medicine (China)

    2015-01-15

    Ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) modified with a novel cyclic arginine-glycine-aspartate (RGD) peptide were made and radiolabeled as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer. The probe was tested both in vitro and in vivo to determine its receptor targeting efficacy and feasibility for SPECT and MRI. The radiochemical syntheses of {sup 125}I-cRGD-USPIO were accomplished with a radiochemical purity of 96.05 ± 0.33 %. High radiochemical stability was found in fresh human serum and in phosphate-buffered saline. The average hydrodynamic size of {sup 125}I-cRGD-USPIO determined by dynamic light scattering was 51.3 nm. Results of in vitro experiments verified the specificity of the radiolabeled nanoparticles to tumor cells. Preliminary biodistribution studies of {sup 125}I-radiolabeled cRGD-USPIO in Bcap37-bearing nude mice showed that it had long circulation half-life, high tumor uptake, and high initial blood retention with moderate liver uptake. In vivo tumor targeting and uptake of the radiolabeled nanoparticles in mice model were visualized by SPECT and MRI collected at different time points. Our results strongly indicated that the {sup 125}I-cRGD-USPIO could be used as a promising bifunctional radiotracer for early clinical tumor detection with high sensitivity and high spatial resolution by SPECT and MRI.

  12. Ictal technetium-99 m ethyl cysteinate dimer single-photon emission tomographic findings in epileptic patients with polymicrogyria syndromes: A subtraction of ictal-interictal SPECT coregistered to MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Wichert-Ana, Lauro [University of Sao Paulo, Center for Epilepsy Surgery, Department of Neurology, Psychiatry and Clinical Psychology, Ribeirao Preto (Brazil); Hospital das Clinicas, USP, Centro de Cirurgia de Epilepsia, CIREP, Ribeirao Preto, SP (Brazil); Mazzoncini de Azevedo-Marques, Paulo; Santos, Antonio C.; Araujo, David [University of Sao Paulo, Center for Imaging Science and Medical Physics, Department of Internal Medicine, Ribeirao Preto (Brazil); Ferrari Oliveira, Lucas [Federal University of Pelotas, Informatics Department, Pelotas, RS (Brazil); Fernandes, Regina M.F.; Velasco, Tonicarlo R.; Sakamoto, Americo C. [University of Sao Paulo, Center for Epilepsy Surgery, Department of Neurology, Psychiatry and Clinical Psychology, Ribeirao Preto (Brazil); Kato, Mery [University of Sao Paulo, Division of Nuclear Medicine, Department of Internal Medicine from the Ribeirao Preto Medical School, Ribeirao Preto (Brazil); Muxfeldt Bianchin, Marino [Rio Grande do Sul Federal University, Neurology Division, HCPA, Porto Alegre, RS (Brazil)

    2008-06-15

    To describe the ictal technetium-99 m-ECD SPECT findings in polymicrogyria syndromes (PMG) during epileptic seizures. We investigated 17 patients with PMG syndromes during presurgical workup, which included long-term video-electroencephalographic (EEG) monitoring, neurological and psychiatry assessments, invasive EEG, and the subtraction of ictal-interictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM). The analysis of the PMG cortex, using SISCOM, revealed intense hyperperfusion in the polymicrogyric lesion during epileptic seizures in all patients. Interestingly, other localizing investigations showed heterogeneous findings. Twelve patients underwent epilepsy surgery, three achieved seizure-freedom, five have worthwhile improvement, and four patients remained unchanged. Our study strongly suggests the involvement of PMG in seizure generation or early propagation. Both conventional ictal single-photon emission computed tomography (SPECT) and SISCOM appeared as the single contributive exam to suggest the localization of the epileptogenic zone. Despite the limited number of resective epilepsy surgery in our study (n = 9), we found a strong prognostic role of SISCOM in predicting surgical outcome. This result may be of great value on surgical decision-making of whether or not the whole or part of the PMG lesion should be surgically resected. (orig.)

  13. Radiolabeled cyclic arginine-glycine-aspartic (RGD)-conjugated iron oxide nanoparticles as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer

    International Nuclear Information System (INIS)

    Ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) modified with a novel cyclic arginine-glycine-aspartate (RGD) peptide were made and radiolabeled as single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) dual-modality agents for imaging of breast cancer. The probe was tested both in vitro and in vivo to determine its receptor targeting efficacy and feasibility for SPECT and MRI. The radiochemical syntheses of 125I-cRGD-USPIO were accomplished with a radiochemical purity of 96.05 ± 0.33 %. High radiochemical stability was found in fresh human serum and in phosphate-buffered saline. The average hydrodynamic size of 125I-cRGD-USPIO determined by dynamic light scattering was 51.3 nm. Results of in vitro experiments verified the specificity of the radiolabeled nanoparticles to tumor cells. Preliminary biodistribution studies of 125I-radiolabeled cRGD-USPIO in Bcap37-bearing nude mice showed that it had long circulation half-life, high tumor uptake, and high initial blood retention with moderate liver uptake. In vivo tumor targeting and uptake of the radiolabeled nanoparticles in mice model were visualized by SPECT and MRI collected at different time points. Our results strongly indicated that the 125I-cRGD-USPIO could be used as a promising bifunctional radiotracer for early clinical tumor detection with high sensitivity and high spatial resolution by SPECT and MRI

  14. High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease)

    Energy Technology Data Exchange (ETDEWEB)

    De Chiara, S.; Lassen, N.A.; Andersen, A.R.; Gade, A.; Lester, J.; Thomsen, C.; Henriksen, O.

    1987-01-01

    Pure sensory stroke (PSS) is typically caused by a lacunar infarct located in the ventral-posterior (VP) thalamic nucleus contralateral to the paresthetic symptoms. The lesion is usually so small that it cannot be seen on computerized tomography (CT), as illustrated by our case. In our moderately hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen. In addition, NMRI unexpectedly showed diffuse periventricular demyelinization as well as three other lacunar infarcts, i.e., findings characteristic of subcortical arteriosclerotic encephalopathy (SAE). This prompted psychometric testing, which revealed signs of mild (subclinical) dementia, in particular involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric distribution of cerebral blood flow (CBF), with an 18% lower value in the right parietal cortex compared to the left side; this indicated asymmetric disconnection of the cortex by the SAE. Thus, the tomograms of the functional parameter, CBF, correlated better with the deficits revealed by neuropsychological testing than by CT or NMRI.

  15. Ictal technetium-99 m ethyl cysteinate dimer single-photon emission tomographic findings in epileptic patients with polymicrogyria syndromes: A subtraction of ictal-interictal SPECT coregistered to MRI study

    International Nuclear Information System (INIS)

    To describe the ictal technetium-99 m-ECD SPECT findings in polymicrogyria syndromes (PMG) during epileptic seizures. We investigated 17 patients with PMG syndromes during presurgical workup, which included long-term video-electroencephalographic (EEG) monitoring, neurological and psychiatry assessments, invasive EEG, and the subtraction of ictal-interictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM). The analysis of the PMG cortex, using SISCOM, revealed intense hyperperfusion in the polymicrogyric lesion during epileptic seizures in all patients. Interestingly, other localizing investigations showed heterogeneous findings. Twelve patients underwent epilepsy surgery, three achieved seizure-freedom, five have worthwhile improvement, and four patients remained unchanged. Our study strongly suggests the involvement of PMG in seizure generation or early propagation. Both conventional ictal single-photon emission computed tomography (SPECT) and SISCOM appeared as the single contributive exam to suggest the localization of the epileptogenic zone. Despite the limited number of resective epilepsy surgery in our study (n = 9), we found a strong prognostic role of SISCOM in predicting surgical outcome. This result may be of great value on surgical decision-making of whether or not the whole or part of the PMG lesion should be surgically resected. (orig.)

  16. 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)

  17. Assessment of cerebral perfusion with single-photon emission tomography in normal subjects and in patients with Alzheimer's disease: effects of region of interest selection

    International Nuclear Information System (INIS)

    We compared three different ROIs in a SPET study with 60 controls and in 48 patients with probable Alzheimer's disease diagnosed according to the NINCDS-ADRDA criteria. Regional cerebral blood flow (rCBF) was assessed with SPET using technetium-99m d,l-hexamethylpropylene amine oxime (99mTc-HMPAO), normalized to the mean activity in a cerebellar reference slice. The three different ROIs were: a multi-slice and a single-slice ROI with reference to the normal brain anatomy (using an anatomical atlas), and a rectangular (2x4 pixels) ROI in the frontal, temporal, temporoparietal and occipital cortices. No differences were observed for the means of rCBF values between the single-slice and multi-slice ROI's with reference to the normal anatomy, but some variability was present for individual comparisons. In contrast, significantly higher mean rCBF values were obtained with the single-slice rectangular ROIs in all four regions for both patients and controls and considerable variability was shown for individual subjects. After analysis with multivariate logistic regression and receiver operator characteristic curves, the ability of SPET to discriminate between controls and Alzheimer patients was similar in the three methods for mild and moderate Alzheimer patients (Global Deterioration Scale = GDS of 3 and 4). However, with increasing dementia severity (GDS>4) the rectangular ROIs showed lower ability to discriminate between groups compared to the single-slice and multi-slice anatomically defined ROIs. This study suggests that results of rCBF assessment with SPET using 99mTc-HMPAO in patients with severe Alzheimer's disease are influenced by the shape and size of the ROI. (orig.)

  18. Changes in distribution of reticuloendothelial function in transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC), estimated by single photon emission computed tomography (SPECT)

    Energy Technology Data Exchange (ETDEWEB)

    Taniai, Nobuhiko; Onda, Masahiko; Tajiri, Takashi; Kim, Tokuei [Nippon Medical School, Tokyo (Japan)

    1995-06-01

    In order to study the changes in distribution of reticuloendothelial function in transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC), the radioactivity of {sup 99m}Tc-phytate was calculated by the accumulation rate in the organs by means of the single emission computed tomography (SPECT). It was regarded as the reticuloendothelial function in the liver and spleen, and was evaluated independently. Before TAE, the significant increases were noted in both splenic activity and splenic volume in the cirrhotic patients, as compared with non-cirrhotic patients. After TAE, the activity in the liver was reduced at the first day after TAE, which returned to the normal level by 5 days. While that in the spleen increased immediately after TAE. After one day of TAE, reticuloendothelial functions of the spleen was significantly higher in the cirrhotic cases then in the non-cirrhotic cases. Furthermore, in the cirrhotic patients, it was significantly higher in the cases embolizated in more than two segments than in those embolizated in one segment only. In conclusion, the reticuloendothelial function of the liver was significantly reduced by the TAE in the cirrhotic patients as compared with non-cirrhotic patients. However the reduced reticuloendothelial function of the liver in the cirrhotic patients was compensated by the increased reticuloendothelial function of the spleen. (author).

  19. Ictal technetium-99m ethyl cysteinate dimer single-photon emission tomographic findings and propagation of epileptic seizure activity in patients with extratemporal epilepsies

    Energy Technology Data Exchange (ETDEWEB)

    Noachtar, S.; Arnold, S.; Werhahn, K.J. [Department Neurologie, Ludwig-Maximilians Universitaet, Muenchen (Germany); Yousry, T.A. [Muenchen Univ. (Germany). Abt. fuer Neuroradiologie; Bartenstein, P. [Department of Nuclear Medicine, Technical University of Munich, Munich (Germany); Tatsch, K. [Department of Nuclear Medicine, Ludwig-Maximilians University of Munich, Munich (Germany)

    1998-02-01

    We investigated the influence of the propagation of extratemporal epileptic seizure activity on the regional increase in cerebral blood flow, which is usually associated with epileptic seizure activity. Forty-two consecutive patients with extratemporal epilepsies were prospectively evaluated. All patients underwent ictal SPET studies with simultaneous electroencephalography (EEG) and video recordings of habitual seizures and imaging studies including cranial magnetic resonance imaging and positron emission tomography with 2-[{sup 18}F]-fluoro-2 deoxy-d-glucose. Propagation of epilptic seizure activity (PESA) was defined as the absence of hyperperfusion on ictal ECD SPET in the lobe of seizure onset, but its presence in another ipsilateral or contralateral lobe. Observers analysing the SPET images were not informed of the other results. PESA was observed in 8 of the 42 patients (19%) and was ipsilateral to the seizure onset in five (63%) of these eight patients. The time between clinical seizure onset and injection of the ECD tracer ranged from 14 to 61 s (mean 34 s). Seven patients (88%) with PESA had parieto-occipital epilepsy and one patient had a frontal epilepsy. PESA was statistically more frequent in patients with parieto-occipital lobe epilepsies (58%) than in the remaining extratemporal epilepsy syndromes (3%) (P<0.0002). These findings indicate that ictal SPET studies require simultaneous EEG-video recordings in patients with extratemporal epilepsies. PESA should be considered when interpreting ictal SPET studies in these patients. Patients with PESA are more likely to have parieto-occipital lobe epilepsy than seizure onset in other extratemporal regions. (orig./MG) (orig.) With 1 fig., 2 tabs., 23 refs.

  20. Room temperature triggered single-photon source in the near infrared

    International Nuclear Information System (INIS)

    We report the realization of a solid-state triggered single-photon source with narrow emission in the near infrared at room temperature. It is based on the photoluminescence of a single nickel-nitrogen NE8 colour centre in a chemical vapour deposited diamond nanocrystal. Stable single-photon emission has been observed in the photoluminescence under both continuous-wave and pulsed excitations. The realization of this source represents a step forward in the application of diamond-based single-photon sources to quantum key distribution (QKD) under practical operating conditions

  1. A highly efficient single-photon source based on a quantum dot in a photonic nanowire

    DEFF Research Database (Denmark)

    Claudon, Julien; Bleuse, Joel; Malik, Nitin Singh;

    2010-01-01

    The development of efficient solid-state sources of single photons is a major challenge in the context of quantum communication,optical quantum information processing and metrology1. Such a source must enable the implementation of a stable, single-photon emitter, like a colour centre in diamond2...... with carefully tailored ends13. Under optical pumping, we demonstrate a record source efficiency of 0.72, combined with pure single-photon emission. This non-resonant approach also provides broadband spontaneous emission control, thus offering appealing novel opportunities for the development of single...

  2. A novel high-efficiency single-mode quantum dot single photon source

    DEFF Research Database (Denmark)

    Gerard, J.M.; Gregersen, Niels; Nielsen, Torben Roland;

    2008-01-01

    We present a novel single-mode single photon source exploiting the emission of a semiconductor quantum dot (QD) located inside a photonic wire. Besides an excellent coupling (>95%) of QD spontaneous emission to the fundamental guided mode [1], we show that a single photon collection efficiency...... above 80% within a 0.5 numerical aperture can be achieved using a bottom Bragg mirror and a tapering of the nanowire tip. Because this photon collection strategy does not exploit the Purcell effect, it could also be efficiently applied to broadband single photon emitters such as F-centers in diamond....

  3. Localization of narrowband single photon emitters in nanodiamonds

    CERN Document Server

    Bray, Kerem; Elbadawi, Christopher; Fischer, Martin; Schreck, Matthias; Shimoni, Olga; Lobo, Charlene; Toth, Milos; Aharonovich, Igor

    2016-01-01

    Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bio-imaging. However, current understanding of the origin of these emitters is extremely limited. In this work we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond, and are directly relevant to fabrication of novel quantum optics devices and sensors.

  4. Stroing single-photons in microcavities arrays

    Science.gov (United States)

    Mirza, Imran M.; Enk, S. J. Van; Kimble, H. J.

    2014-03-01

    Coupling light to arrays of microcavities is one of the most promising avenues to store/delay classical light pulses [F. Krauss, Nat. Phot. 2, 448-450 (2008)]. However, from the perspective of benefiting quantum communication protocols, the same ideas in principle can be extended down to the single-photon (quantum) level as well. Particularly, for the purposes of entanglement purification and quantum repeaters a reliable storage of single photons is needed. We consider in our work [I. M. Mirza, S. Van Enk, H. Kimble JOSA B, 30,10 (2013)] cavities that are coupled through an optical fiber which is assumed to be forming a Markovian bath. For this study two powerful open quantum system techniques, Input-Output theory for cascaded quantum systems and the Quantum Trajectory approach are used in combination. For the confirmation of photon delays the Time-Dependent Spectrum of such a single photon is obtained. Interestingly this leads to a hole-burning effect showing that only certain frequency components in the single photon wavepackets are stored inside the cavities and hence are delayed in time. Since on-demand production of single photons is not an easy task we include in our description the actual generation of the single photon by assuming a single emitter in one the resonators.

  5. [{sup 123}I]-3-Iodcytisin as possible radiotracer for the imaging of nicotinic acetylcholine receptors using single photon emission computer tomography; [{sup 123}I]-3-Iodcytisin als moeglicher Radiotracer fuer die Darstellung der nikotinergen Acetylcholin Rezeptoren mittels Single-Photon-Emissions-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Paulik, Dagmar Julia

    2015-03-06

    For the synthesis of [{sup 123}I]-3-Iodcytisin as possible radiotracer for the imaging of nicotinic acetylcholine (nACh) receptors using SPECT two different technologies were used: the radio-iodination with iodogen and the radio-iodination with nitric acid. The latter one showed higher efficiency. The radiotracer will allow to detect degenerative processes and other nACh-depending diseases in the brain (Alzheimer, Parkinson) and to observe the progress. The autoradiography is aimed to the imaging of the nACh receptors in the brain bypassing the brain-blood barrier. The highest activity was measured in the thalamus of mice and rat brains.

  6. A brain phantom for studying contrast recovery in emission computerized tomography

    International Nuclear Information System (INIS)

    A brain phantom is described that is characterized by a high anatomical definition and by the possibility of varying the internal contrast with the use of a single radioactive solution. The experimental work was done with a single-photon emission tomographic (SPET) rotating camera. The phantom was used to study the contrast recovery of both the filtered back-projection and an iterative reconstruction algorithm. Moreover, it was also used to find a cross-calibration factor between activity concentrations in the SPET slices and an external reference. (orig.)

  7. Indium-111 pentetreotide single-photon emission tomography in patients with TSH-secreting pituitary adenomas: correlation with the effect of a single administration of octreotide on serum TSH levels

    Energy Technology Data Exchange (ETDEWEB)

    Losa, M. [Department of Neurosurgery, IRCCS San Raffaele, University of Milan (Italy); Magnani, P. [INB-CNR Department of Nuclear Medicine, IRCCS San Raffaele, University of Milan (Italy); Mortini, P. [Department of Neurosurgery, IRCCS San Raffaele, University of Milan (Italy); Persani, L. [Centro Auxologico Italiano IRCCS, University of Milan (Italy); Acerno, S. [Department of Neurosurgery, IRCCS San Raffaele, University of Milan (Italy); Giugni, E. [Department of Neurosurgery, IRCCS San Raffaele, University of Milan (Italy); Songini, C. [INB-CNR Department of Nuclear Medicine, IRCCS San Raffaele, University of Milan (Italy); Fazio, F. [INB-CNR Department of Nuclear Medicine, IRCCS San Raffaele, University of Milan (Italy); Beck-Peccoz, P. [Institute of Endocrine Sciences, Istituto Clinico Humanitas, University of Milan (Italy); Giovanelli, M. [Department of Neurosurgery, IRCCS San Raffaele, University of Milan (Italy)

    1997-07-01

    Few data are available on the visualization of somatostatin receptors in vivo in patients with thyrotropin (TSH)-secreting adenoma. We studied five patients with TSH-secreting adenomas using single-photon emission tomography (SPET) after administration of indium-111 pentetreotide. The intensity of {sup 111}In-pentetreotide uptake by the tumours was correlated with the degree of TSH suppression after a single administration of 100 {mu}g octreotide s.c. Five patients (three women and two men) aged 27-46 years were investigated. Except for one patient with acromegaly, all had pure TSH-secreting tumours. One patient was previously untreated, while two had received octreotide, one antithyroid drugs, and one radioiodine. In all patients SPET demonstrated increased uptake of {sup 111}In-pentetreotide by the pituitary adenoma. The target to non-target ratio (T/nT) of {sup 111}In-pentetreotide uptake was higher than 10 in three patients. Administration of 100 {mu}g octreotide s.c. caused a significant reduction in TSH levels from 4.8{+-}1.4 mU/l to a nadir of 3.1{+-}1.1 mU/l after 6 h (P<0.001 by ANOVA). Suppression of TSH secretion ranged from 30% to 60% of the baseline value. The T/nT ratio showed a trend toward a direct relationship with the degree of TSH inhibition after acute octreotide administration (r=0.67; P=NS). Our study showed that {sup 111}In-pentetreotide scan visualized somatostatin receptors in all five of the patients with TSH-secreting pituitary adenomas, confirming the frequent presence of somatostatin receptors in these rare tumours, even though the correlation with the TSH inhibition after a single administration of octreotide did not reach significance. (orig.). With 1 fig., 1 tab.

  8. Comparison of glucose-insulin-thallium-201 infusion single photon emission computed tomography (SPECT), stress-redistribution-reinjection thallium-201 SPECT and low dose dobutamine echocardiography for prediction of reversible dysfunction

    International Nuclear Information System (INIS)

    The usefulness of glucose-insulin-thallium-201 (GI-Tl) infusion single photon emission computed tomography (SPECT) in predicting reversible dysfunction has not been evaluated, so the present study recruited 20 patients with regional ischemic dysfunction for investigation. All patients underwent GI-Tl SPECT, post-stress Tl reinjection imaging and low dose dobutamine echocardiography. The diagnostic accuracy of these 3 techniques in predicting functional recovery was evaluated by receiver operating characteristic (ROC) analysis. In segments with functional recovery, regional Tl activities of GI-Tl SPECT were significantly higher than those of reinjection imaging (p<0.05), although there were no significant differences in segments without recovery. The area under the ROC curve for GI-Tl SPECT (0.75±0.06) was greater than that for reinjection imaging (0.68±0.07). The optimal cutoff values to identify viable myocardium were considered to be 55% of peak activity for GI-Tl SPECT and 50% for reinjection imaging. At this cutoff point, the sensitivity and specificity for detection of functional recovery were, respectively, 85% and 61% for GI-Tl SPECT, and 73% and 61% for reinjection imaging. Dobutamine echocardiography had the same sensitivity (85%), but lower specificity (48%) than GI-Tl SPECT. Continuous infusion of GI-Tl solution enhances regional Tl uptake compared with conventional post-stress reinjection imaging. This study suggests that GI-Tl SPECT is superior to reinjection imaging and dobutamine echocardiography in predicting functional recovery after ischemic left ventricular dysfunction. (author)

  9. A Pilot Study Measuring the Distribution and Permeability of a Vaginal HIV Microbicide Gel Vehicle Using Magnetic Resonance Imaging, Single Photon Emission Computed Tomography/Computed Tomography, and a Radiolabeled Small Molecule.

    Science.gov (United States)

    Fuchs, Edward J; Schwartz, Jill L; Friend, David R; Coleman, Jenell S; Hendrix, Craig W

    2015-11-01

    Vaginal microbicide gels containing tenofovir have proven effective in HIV prevention, offering the advantage of reduced systemic toxicity. We studied the vaginal distribution and effect on mucosal permeability of a gel vehicle. Six premenopausal women were enrolled. In Phase 1, a spreading gel containing (99m)technetium-DTPA ((99m)Tc) radiolabel and gadolinium contrast for magnetic resonance imaging (MRI) was dosed intravaginally. MRI was obtained at 0.5, 4, and 24 h, and single photon emission computed tomography with conventional computed tomography (SPECT/CT) at 1.5, 5, and 25 h postdosing. Pads and tissues were measured for activity to determine gel loss. In Phase 2, nonoxynol-9 (N-9), containing (99m)Tc-DTPA, was dosed as a permeability control; permeability was measured in blood and urine for both phases. SPECT/CT showed the distribution of spreading gel throughout the vagina with the highest concentration of radiosignal in the fornices and ectocervix; signal intensity diminished over 25 h. MRI showed the greatest signal accumulation in the fornices, most notably 1-4 h postdosing. The median (interquartile range) isotope signal loss from the vagina through 6 h was 29.1% (15.8-39.9%). Mucosal permeability to (99m)Tc-DTPA following spreading gel was negligible, in contrast to N-9, with detectable radiosignal in plasma, peaking at 8 h (5-12). Following spreading gel dosing, 0.004% (0.001-2.04%) of the radiosignal accumulated in urine over 12 h compared to 8.31% (7.07-11.01%) with N-9, (p=0.043). Spreading gel distributed variably throughout the vagina, persisting for 24 h, with signal concentrating in the fornices and ectocervix. The spreading gel had no significant effect on vaginal mucosal permeability. PMID:26077739

  10. Distribution of Functional Liver Volume in Hepatocellular Carcinoma Patients with Portal Vein Tumor Thrombus in the 1st Branch and Main Trunk Using Single Photon Emission Computed Tomography—Application to Radiation Therapy

    Directory of Open Access Journals (Sweden)

    Akira Ikoma

    2011-10-01

    Full Text Available Purpose: To analyze the distribution of functional liver volume (FLV in the margin volume (MV surrounding hepatocellular carcinoma (HCC with portal vein tumor thrombus (PVTT before radiation therapy (RT and to verify the safety of single photon emission computed tomography-based three-dimensional conformal radiotherapy (SPECT-B3DCRT by exploring the relation of FLV in MV to radiation-induced liver disease (RILD. Methods and Materials: Clinical target volume (CTV included main tumor and PVTT, and planning target volume (PTV included CTV with a 10 mm margin. MV was defined as PTV–CTV. FLV ratio in MV was calculated as FLV in MV/MV × 100 (%. The two high-dose beams were planned to irradiate FLV as little as possible. Fifty-seven cases of HCC (26/57, 46%; Child–Pugh grade B with PVTT underwent SPECT-B3DCRT which targeted the CTV to a total dose of 45 Gy/18 fractions. The destructive ratio was defined as radiation induced dysfunctional volume/FLV × 100 (%. Results: We observed a significant negative correlation between FLV ratio in MV and CTV (p < 0.001. Three cases with CTVs of 287, 587 and 1184 cm3 experienced transient RILD. The FLV ratio in MV was highest in patients with RILD: nine patients with CTV of 200–300 cm3, three with CTV of 500–600 cm3, and two with CTV of 1100–1200 cm3. The destructive ratio yielded a mean value of 24.2 ± 1.5%. Conclusions: Radiation planning that takes into account the distribution of FLV appears to result in the least possible RILD.

  11. Prognostic value of myocardial perfusion single photon emission computed tomography for major adverse cardiac cerebrovascular and renal events in patients with chronic kidney disease: results from first year of follow-up of the Gunma-CKD SPECT multicenter study

    International Nuclear Information System (INIS)

    Patients with chronic kidney disease (CKD) have an increased risk of adverse cardio-cerebrovascular events. We examined whether stress myocardial perfusion single photon emission computed tomography (SPECT) provides reliable prognostic markers for these patients. In this multicenter, prospective cohort trial from the Gunma-CKD SPECT study protocol, patients with CKD [estimated glomerular filtration rate (eGFR) < 60 min/ml per 1.73 m2] undergoing stress 99mTc-tetrofosmin SPECT for suspected or possible ischemic heart disease were initially followed for 1 year, with the following study endpoints: primary, the occurrence of cardiac deaths (CDs), and secondary, major adverse cardiac, cerebrovascular, and renal events (MACCREs). The summed stress score (SSS), summed rest score, and summed difference score (SDS) were estimated with the standard 17-segment, 5-point scoring model. Left ventricular end-diastolic volume, end-systolic volume (ESV), and ejection fraction were measured using electrocardiogram-gated SPECT. During the first year of follow-up, 69 of 299 patients experienced MACCREs (CD, n = 7; non-fatal myocardial infarction, n = 3; hospitalization for heart failure, n = 13; cerebrovascular accident, n = 1; need for revascularization, n = 38; and renal failure, i.e., hemodialysis initiation, n = 7). ESV and SSS were associated with CDs (p < 0.05), and eGFR and SDS were associated with MACCREs (p < 0.05), in multivariate logistic analysis. Patients with high ESV and high SSS had a significantly higher CD rate during the first year than the other CKD patient subgroups (p < 0.05). Patients with low eGFR and high SDS had a significantly higher MACCRE rate than the other subgroups (p < 0.05). Myocardial perfusion SPECT can provide reliable prognostic markers for patients with CKD. (orig.)

  12. Distribution of Functional Liver Volume in Hepatocellular Carcinoma Patients with Portal Vein Tumor Thrombus in the 1st Branch and Main Trunk Using Single Photon Emission Computed Tomography—Application to Radiation Therapy

    International Nuclear Information System (INIS)

    To analyze the distribution of functional liver volume (FLV) in the margin volume (MV) surrounding hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) before radiation therapy (RT) and to verify the safety of single photon emission computed tomography-based three-dimensional conformal radiotherapy (SPECT-B3DCRT) by exploring the relation of FLV in MV to radiation-induced liver disease (RILD). Clinical target volume (CTV) included main tumor and PVTT, and planning target volume (PTV) included CTV with a 10 mm margin. MV was defined as PTV–CTV. FLV ratio in MV was calculated as FLV in MV/MV × 100 (%). The two high-dose beams were planned to irradiate FLV as little as possible. Fifty-seven cases of HCC (26/57, 46%; Child–Pugh grade B) with PVTT underwent SPECT-B3DCRT which targeted the CTV to a total dose of 45 Gy/18 fractions. The destructive ratio was defined as radiation induced dysfunctional volume/FLV × 100 (%). We observed a significant negative correlation between FLV ratio in MV and CTV (p < 0.001). Three cases with CTVs of 287, 587 and 1184 cm3 experienced transient RILD. The FLV ratio in MV was highest in patients with RILD: nine patients with CTV of 200–300 cm3, three with CTV of 500–600 cm3, and two with CTV of 1100–1200 cm3. The destructive ratio yielded a mean value of 24.2 ± 1.5%. Radiation planning that takes into account the distribution of FLV appears to result in the least possible RILD

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

    Energy Technology Data Exchange (ETDEWEB)

    Shimoyama, Katsuya [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1999-10-01

    Dual single photon emission computed tomography (SPECT) was performed in 31 patients with Duchenne's progressive muscular dystrophy (DMD) using {sup 123}I-{beta}-methyl pentadecanoic acid (BMIPP) for myocardial fatty acid metabolism and {sup 201}thallium (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<0.042). However, when Tl defect score was larger than BMIPP defect score, an increase in Tl defect score was slight. A significant negative correlation was found between the sum of the BMIPP and Tl defect scores and the left ventricular ejection fraction (LVEF) (r=0.66, p<0.0001). According to the histo-pathological study of two autopsied hearts, severe myocardial fibrosis was seen in segments with fixed perfusion defect. In addition, the mismatched segments of BMIPP defect score > 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)

  14. Prognostic value of myocardial perfusion single photon emission computed tomography for major adverse cardiac cerebrovascular and renal events in patients with chronic kidney disease: results from first year of follow-up of the Gunma-CKD SPECT multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Kasama, Shu [Gunma University Graduate School of Medicine, Department of Medicine and Biological Science (Cardiovascular Medicine), Maebashi, Gunma (Japan); Cardiovascular Hospital of Central Japan (Kitakanto Cardiovascular Hospital), Department of Cardiovascular Medicine, Gunma (Japan); Toyama, Takuji [Department of Cardiovascular Medicine, Gunma Prefectural Cardiovascular Center, Maebashi (Japan); Sato, Makito [Gunma University Graduate School of Medicine, Department of Medicine and Biological Science (Cardiovascular Medicine), Maebashi, Gunma (Japan); Tatebayashi Kosei Hospital, Department of Internal Medicine, Gunma (Japan); Sano, Hirokazu [Gunma University Graduate School of Medicine, Department of Medicine and Biological Science (Cardiovascular Medicine), Maebashi, Gunma (Japan); Isesaki Municipal Hospital, Department of Cardiovascular Medicine, Isesaki (Japan); Ueda, Tetsuya [Fujioka General Hospital, Division of Cardiology, Fujioka (Japan); Sasaki, Toyoshi [Takasaki General Medical Center, Division of Cardiology, Takasaki (Japan); Nakahara, Takehiro; Kurabayashi, Masahiko [Gunma University Graduate School of Medicine, Department of Medicine and Biological Science (Cardiovascular Medicine), Maebashi, Gunma (Japan); Higuchi, Tetsuya; Tsushima, Yoshito [Gunma University Graduate School of Medicine, Department of Diagnostic Radiology and Nuclear Medicine, Maebashi (Japan)

    2016-02-15

    Patients with chronic kidney disease (CKD) have an increased risk of adverse cardio-cerebrovascular events. We examined whether stress myocardial perfusion single photon emission computed tomography (SPECT) provides reliable prognostic markers for these patients. In this multicenter, prospective cohort trial from the Gunma-CKD SPECT study protocol, patients with CKD [estimated glomerular filtration rate (eGFR) < 60 min/ml per 1.73 m{sup 2}] undergoing stress {sup 99m}Tc-tetrofosmin SPECT for suspected or possible ischemic heart disease were initially followed for 1 year, with the following study endpoints: primary, the occurrence of cardiac deaths (CDs), and secondary, major adverse cardiac, cerebrovascular, and renal events (MACCREs). The summed stress score (SSS), summed rest score, and summed difference score (SDS) were estimated with the standard 17-segment, 5-point scoring model. Left ventricular end-diastolic volume, end-systolic volume (ESV), and ejection fraction were measured using electrocardiogram-gated SPECT. During the first year of follow-up, 69 of 299 patients experienced MACCREs (CD, n = 7; non-fatal myocardial infarction, n = 3; hospitalization for heart failure, n = 13; cerebrovascular accident, n = 1; need for revascularization, n = 38; and renal failure, i.e., hemodialysis initiation, n = 7). ESV and SSS were associated with CDs (p < 0.05), and eGFR and SDS were associated with MACCREs (p < 0.05), in multivariate logistic analysis. Patients with high ESV and high SSS had a significantly higher CD rate during the first year than the other CKD patient subgroups (p < 0.05). Patients with low eGFR and high SDS had a significantly higher MACCRE rate than the other subgroups (p < 0.05). Myocardial perfusion SPECT can provide reliable prognostic markers for patients with CKD. (orig.)

  15. 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.

  16. Relationship of infarct size and severity versus left ventricular ejection fraction and volumes obtained from {sup 99m}Tc-sestamibi gated single-photon emission computed tomography in patients treated with primary percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Sciagra, Roberto; Imperiale, Alessio; Comis, Giannetto; Pupi, Alberto [Nuclear Medicine Unit, Department of Clinical Physiopathology, University of Florence, Viale Morgagni 85, 50134, Florence (Italy); Antoniucci, David; Migliorini, Angela; Parodi, Guido [Division of Cardiology, Careggi Hospital, Florence (Italy)

    2004-07-01

    The current technique of choice for perfusion imaging is gated single-photon emission computed tomography (SPECT), which allows the simultaneous assessment of perfusion and left ventricular (LV) function. We examined the relationships of infarct size and severity with LV ejection fraction (EF) and volumes in 215 myocardial infarction patients treated with primary percutaneous coronary intervention within 6 h of symptom onset. Patients were studied with resting gated SPECT 1 month later. Infarct size was expressed as LV percent, and infarct severity as the lowest activity ratio within the defect. LVEF, end-diastolic (ED) and end-systolic (ES) volume indexes (Vi) were calculated with commercial software. There was a significant correlation between infarct size and LVEF (r=-0.68, P<0.00001), EDVi (r=0.53, P<0.00001), and ESVi (r=0.62, P<0.00001). Slightly lower correlations were demonstrated using infarct severity. LVEF and volumes were related to infarct location. A significantly higher correlation was observed between infarct size and LVEF in anterior than in non-anterior infarctions (r=-0.75 vs -0.60, P<0.05). In multivariate analysis, infarct size and infarct location were significant predictors of LVEF (R{sup 2}=0.50) and ESV (R{sup 2}=0.40). Infarct size and infarct severity were significant predictors of EDVi (R{sup 2}=0.29). Infarct size (and severity) and LVEF (and volumes) derived from a single gated SPECT study correlate closely. Infarct location influences this relationship, with anterior infarctions showing a lower LVEF than inferior or lateral ones of the same extent. (orig.)

  17. Impact of intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction on left ventricular perfusion and function: a 6-month follow-up gated {sup 99m}Tc-MIBI single-photon emission computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Lipiec, Piotr [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Medical University of Lodz, 2nd Department of Cardiology, Bieganski Hospital, Lodz (Poland); Krzeminska-Pakula, Maria; Plewka, Michal; Kasprzak, Jaroslaw D. [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Kusmierek, Jacek; Plachcinska, Anna; Szuminski, Remigiusz [Medical University of Lodz, Department of Nuclear Medicine, Lodz (Poland); Robak, Tadeusz; Korycka, Anna [Medical University of Lodz, Department of Hematology, Lodz (Poland)

    2009-04-15

    We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p=0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score index did not differ significantly between the groups. Intracoronary injection of autologous mononuclear BMC in patients with STEMI improves myocardial perfusion at 6 months. The benefit in infarct area systolic function is less pronounced and there is no apparent improvement of global left ventricular systolic function. (orig.)

  18. 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)

  19. Positron emission tomography studies in the normal and abnormal ageing of human brain

    International Nuclear Information System (INIS)

    Until recently, the investigation of the neurophysiological correlates of normal and abnormal ageing of the human brain was limited by methodological constraints, as the technics available provided only a few parameters (e.g. electroencephalograms, cerebral blood flow) monitored in superficial brain structures in a grossly regional and poorly quantitative way. Lately several non invasive techniques have been developed which allow to investigate in vivo both quantitatively and on local basis a number of previously inaccessible important aspects of brain function. Among these techniques, such as single photon emission tomography imaging of computerized electric events, nuclear magnetic resonance, positron emission tomography stands out as the most powerful and promising method since it allows the in vivo measurement of biochemical and pharmacological parameters

  20. Efficient generation of indistinguishable single photons on-demand at telecom wavelengths

    Science.gov (United States)

    Kim, Jehyung; Cai, Tao; Richardson, Christopher; Leavitt, Richard; Waks, Edo

    Highly efficient single photon sources are important building blocks for optical quantum information processing. For practical use and long-distance quantum communication, single photons should have fiber-compatible telecom wavelengths. In addition, most quantum communication applications require high degree of indistinguishability of single photons, such that they exhibit interference on a beam splitter. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem in particular at telecom wavelengths. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. To obtain the efficient single quantum dot emission, we employ the higher order mode in L3 photonic crystal cavity that shows a nearly Gaussian transverse mode profile and results in out-coupling efficiency exceeding 46 % and unusual bright single quantum dot emission exceeding 1.5 million counts per second at a detector. We also observe Purcell enhanced spontaneous emission rate as large as 4 and high linear polarization ratio of 0.96 for the coupled dots. Using this source, we generate high purity single photons at 1.3 μm wavelength and demonstrate the indistinguishable nature of the emission using a two-photon interference measurement.

  1. A bright on-demand source of indistinguishable single photons at telecom wavelengths

    CERN Document Server

    Kim, Je-Hyung; Richardson, Christopher J K; Leavitt, Richard P; Waks, Edo

    2015-01-01

    Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. In many applications these photons must also be indistinguishable such that they exhibit interference on a beamsplitter, which implements effective photon-photon interactions. However, deterministic generation of indistinguishable single photons with high brightness remains a challenging problem. We demonstrate a telecom wavelength source of indistinguishable single photons using an InAs/InP quantum dot in a nanophotonic cavity. The cavity enhances the quantum dot emission, resulting in a nearly Gaussian transverse mode profile with high out-coupling efficiency exceeding 46%, leading to detected photon count rates that would exceed 1.5 million counts per second. We also observe Purcell enhanced spontaneous emission rate as large as 4. Using this source, we generate linearly polarized, high purity single photons at telecom-wavelength and demonstrate the indistinguishable nature o...

  2. Ultrafast room temperature single-photon source from nanowire-quantum dots.

    Science.gov (United States)

    Bounouar, S; Elouneg-Jamroz, M; Hertog, M den; Morchutt, C; Bellet-Amalric, E; André, R; Bougerol, C; Genuist, Y; Poizat, J-Ph; Tatarenko, S; Kheng, K

    2012-06-13

    Epitaxial semiconductor quantum dots are particularly promising as realistic single-photon sources for their compatibility with manufacturing techniques and possibility to be implemented in compact devices. Here, we demonstrate for the first time single-photon emission up to room temperature from an epitaxial quantum dot inserted in a nanowire, namely a CdSe slice in a ZnSe nanowire. The exciton and biexciton lines can still be resolved at room temperature and the biexciton turns out to be the most appropriate transition for single-photon emission due to a large nonradiative decay of the bright exciton to dark exciton states. With an intrinsically short radiative decay time (≈300 ps) this system is the fastest room temperature single-photon emitter, allowing potentially gigahertz repetition rates.

  3. Superconducting nanowire single-photon imager

    CERN Document Server

    Zhao, Qing-Yuan; Calandri, Niccolò; Dane, Andrew E; McCaughan, Adam N; Bellei, Francesco; Wang, Hao-Zhu; Santavicca, Daniel F; Berggren, Karl K

    2016-01-01

    Detecting spatial and temporal information of individual photons is a crucial technology in today's quantum information science. Among the existing single-photon detectors, superconducting nanowire single-photon detectors (SNSPDs) have been demonstrated with a sub-50 ps timing jitter, near unity detection efficiency1, wide response spectrum from visible to infrared and ~10 ns reset time. However, to gain spatial sensitivity, multiple SNSPDs have to be integrated into an array, whose spatial and temporal resolutions are limited by the multiplexing circuit. Here, we add spatial sensitivity to a single nanowire while preserving the temporal resolution from an SNSPD, thereby turning an SNSPD into a superconducting nanowire single-photon imager (SNSPI). To achieve an SNSPI, we modify a nanowire's electrical behavior from a lumped inductor to a transmission line, where the signal velocity is slowed down to 0.02c (where c is the speed of light). Consequently, we are able to simultaneously read out the landing locati...

  4. Solid-state single-photon emitters

    Science.gov (United States)

    Aharonovich, Igor; Englund, Dirk; Toth, Milos

    2016-10-01

    Single-photon emitters play an important role in many leading quantum technologies. There is still no 'ideal' on-demand single-photon emitter, but a plethora of promising material systems have been developed, and several have transitioned from proof-of-concept to engineering efforts with steadily improving performance. Here, we review recent progress in the race towards true single-photon emitters required for a range of quantum information processing applications. We focus on solid-state systems including quantum dots, defects in solids, two-dimensional hosts and carbon nanotubes, as these are well positioned to benefit from recent breakthroughs in nanofabrication and materials growth techniques. We consider the main challenges and key advantages of each platform, with a focus on scalable on-chip integration and fabrication of identical sources on photonic circuits.

  5. What are single photons good for?

    Science.gov (United States)

    Sangouard, Nicolas; Zbinden, Hugo

    2012-10-01

    In a long-held preconception, photons play a central role in present-day quantum technologies. But what are sources producing photons one by one good for precisely? Well, in opposition to what many suggest, we show that single-photon sources are not helpful for point to point quantum key distribution because faint laser pulses do the job comfortably. However, there is no doubt about the usefulness of sources producing single photons for future quantum technologies. In particular, we show how single-photon sources could become the seed of a revolution in the framework of quantum communication, making the security of quantum key distribution device-independent or extending quantum communication over many hundreds of kilometers. Hopefully, these promising applications will provide a guideline for researchers to develop more and more efficient sources, producing narrowband, pure and indistinguishable photons at appropriate wavelengths.

  6. What are single photons good for?

    CERN Document Server

    Sangouard, Nicolas

    2012-01-01

    In a long-held preconception, photons play a central role in present-day quantum technologies. But what are sources producing photons one by one good for precisely? Well, in opposition to what many suggest, we show that single-photon sources are not helpful for point to point quantum key distribution because faint laser pulses do the job comfortably. However, there is no doubt about the usefulness of sources producing single photons for future quantum technologies. In particular, we show how single-photon sources could become the seed of a revolution in the framework of quantum communication, making the security of quantum key distribution device independent or extending quantum communication over many hundreds of kilometers. Hopefully, these promising applications will provide a guideline for researchers to develop more and more efficient sources, producing narrowband, pure and indistinguishable photons at appropriate wavelengths.

  7. Coherent single-photon absorption by single emitters coupled to one-dimensional nanophotonic waveguides

    DEFF Research Database (Denmark)

    Chen, Yuntian; Wubs, Martijn; Mørk, Jesper;

    2011-01-01

    We study the dynamics of single-photon absorption by a single emitter coupled to a one-dimensional waveguide that simultaneously provides channels for spontaneous emission (SE) decay and a channel for the input photon. We have developed a time-dependent theory that allows us to specify any input ...... can be improved by a further 4% by engineering the dispersion. Efficient single-photon absorption by a single emitter has potential applications in quantum communication and quantum computation....

  8. 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

  9. 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

  10. Single-photon indistinguishability: influence of phonons

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Lodahl, Peter; Jauho, Antti-Pekka;

    2012-01-01

    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...

  11. 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.

  12. 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…

  13. Dissipation-enabled efficient excitation transfer from a single photon to a single quantum emitter

    Science.gov (United States)

    Trautmann, N.; Alber, G.

    2016-05-01

    We propose a scheme for triggering a dissipation-dominated highly efficient excitation transfer from a single-photon wave packet to a single quantum emitter. This single-photon-induced optical pumping turns dominant dissipative processes, such as spontaneous photon emission by the emitter or cavity decay, into valuable tools for quantum information processing and quantum communication. It works for an arbitrarily shaped single-photon wave packet with sufficiently small bandwidth provided a matching condition is satisfied which balances the dissipative rates involved. Our scheme does not require additional laser pulses or quantum feedback and does not rely on high finesse optical resonators. In particular, it can be used to enhance significantly the coupling of a single photon to a single quantum emitter implanted in a one-dimensional waveguide or even in a free space scenario. We demonstrate the usefulness of our scheme for building a deterministic quantum memory and a deterministic frequency converter between photonic qubits of different wavelengths.

  14. Electrically Driven InAs Quantum-Dot Single-Photon Sources

    Institute of Scientific and Technical Information of China (English)

    XIONG Yong-Hua; NIU Zhi-Chuan; DOU Xiu-Ming; SUN Bao-Quan; HUANG She-Song; NI Hai-Qiao; DU Yun; XIA Jian-Bai

    2009-01-01

    Electrically driven single photon source based on single InAs quantum dot (QDs) is demonstrated. The device contains InAs QDs within a planar cavity formed between a bottom AIGaAs/GaAs distributed Bragg reflector (DBR) and a surface GaAs-air interface. The device is characterized by Ⅰ-Ⅴ curve and electroluminescence, and a single sharp exciton emission line at 966 nm is observed. Hanbury Brown and Twiss (HBT) correlation measurements demonstrate single photon emission with suppression of multiphoton emission to below 45% at 80 K

  15. Observation of Single-Photon Switching

    CERN Document Server

    Chen, Y F; Liu, Y C; Yu, I A; Chen, Yong-Fan; Tsai, Zen-Hsiang; Liu, Yu-Chen; Yu, Ite A.

    2005-01-01

    We report an experimental demonstration of single-photon switching in laser-cooled $^{87}$Rb atoms. A resonant probe pulse with an energy per unit area of one photon per $\\lambda^2/2\\pi$ propagates through the optically thick atoms. Its energy transmittance is greater than 63% or loss is less than $e^{-1}$ due to the effect of electromagnetically induced transparency. In the presence of a switching pulse with an energy per unit area of 1.4 photons per $\\lambda^2/2\\pi$, the energy transmittance of the same probe pulse becomes less than 37% or $e^{-1}$. This substantial reduction of the probe transmittance caused by single switching photons has potential applications in single-photon-level nonlinear optics and the manipulation of quantum information.

  16. 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.

  17. Continuous variable teleportation of single photon states

    OpenAIRE

    Ide, Toshiki; Hofmann, Holger Friedrich; Kobayashi, Takayoshi; Furusawa, Akira

    2001-01-01

    The properties of continuous-variable teleportation of single-photon states are investigated. The output state is different from the input state due to the nonmaximal entanglement in the Einstein-Podolsky-Rosen beams. The photon statistics of the teleportation output are determined and the correlation between the field information b obtained in the teleportation process and the change in photon number is discussed. The results of the output photon statistics are applied to the transmission of...

  18. Diamond-based single-photon emitters

    International Nuclear Information System (INIS)

    The exploitation of emerging quantum technologies requires efficient fabrication of key building blocks. Sources of single photons are extremely important across many applications as they can serve as vectors for quantum information-thereby allowing long-range (perhaps even global-scale) quantum states to be made and manipulated for tasks such as quantum communication or distributed quantum computation. At the single-emitter level, quantum sources also afford new possibilities in terms of nanoscopy and bio-marking. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, as they are a photostable solid-state source of single photons at room temperature. In this review, we discuss the state of the art of diamond-based single-photon emitters and highlight their fabrication methodologies. We present the experimental techniques used to characterize the quantum emitters and discuss their photophysical properties. We outline a number of applications including quantum key distribution, bio-marking and sub-diffraction imaging, where diamond-based single emitters are playing a crucial role. We conclude with a discussion of the main challenges and perspectives for employing diamond emitters in quantum information processing.

  19. Recent Advances for High-Efficiency Sources of Single Photons Based on Photonic Nanowires

    DEFF Research Database (Denmark)

    Gerard, J. M.; Claudon, J.; Munsch, M.;

    2012-01-01

    Photonic nanowires have recently been used to tailor the spontaneous emission of embedded quantum dots, and to develop record efficiency single-photon sources. We will present recent developments in this field mainly 1) the observation of a strong inhibition of the spontaneous emission of quantum...... source, 4) progress toward high-efficiency electrical-driven sources....

  20. Superconducting nanowire single photon detector on diamond

    International Nuclear Information System (INIS)

    Superconducting nanowire single photon detectors are fabricated directly on diamond substrates and their optical and electrical properties are characterized. Dark count performance and photon count rates are measured at varying temperatures for 1310 nm and 632 nm photons. A multi-step diamond surface polishing procedure is reported, involving iterative reactive ion etching and mechanical polishing to create a suitable diamond surface for the deposition and patterning of thin film superconducting layers. Using this approach, diamond substrates with less than 300 pm Root Mean Square surface roughness are obtained

  1. Single-Photon Detection at Telecom Wavelengths

    Institute of Scientific and Technical Information of China (English)

    SUN Zhi-Bin; MA Hai-Qiang; LEI Ming; WANG Di; LIU Zhao-Jie; YANG Han-Dong; WU Ling-An; ZHAI Guang-Jie; FENG Ji

    2007-01-01

    A single-photon detector based on an InGaAs avalanche photodiode has been developed for use at telecom wavelengths. A suitable delay and sampling gate modulation circuit are used to prevent positive and negative transient pulses from influencing the detection of true photon induced avalanches. A monostable trigger circuit eliminates the influence of avalanche peak jitter, and a dead time modulation feedback control circuit decreases the afterpulsing. From performance tests we find that at the optimum operation point, the quantum efficiency is 12% and the dark count rate 1.5 × 10-6 ns-1, with a detection rate of 500 kHz.

  2. Purification of a single photon nonlinearity

    CERN Document Server

    Snijders, H; Norman, J; Bakker, M P; Gossard, A; Bowers, J E; van Exter, M P; Bouwmeester, D; Löffler, W

    2016-01-01

    We show that the lifetime-reduced fidelity of a semiconductor quantum dot-cavity single photon nonlinearity can be restored by polarization pre- and postselection. This is realized with a polarization degenerate microcavity in the weak coupling regime, where an output polarizer enables quantum interference of the two orthogonally polarized transmission amplitudes. This allows us to transform incident coherent light into a stream of strongly correlated photons with a second-order correlation function of g2(0)~40, larger than previous experimental results even in the strong-coupling regime. This purification technique might also be useful to improve the fidelity of quantum dot based logic gates.

  3. Ultrabright single-photon source on diamond with electrical pumping at room and high temperatures

    Science.gov (United States)

    Fedyanin, D. Yu; Agio, M.

    2016-07-01

    The recently demonstrated electroluminescence of color centers in diamond makes them one of the best candidates for room temperature single-photon sources. However, the reported emission rates are far off what can be achieved by state-of-the-art electrically driven epitaxial quantum dots. Since the electroluminescence mechanism has not yet been elucidated, it is not clear to what extent the emission rate can be increased. Here we develop a theoretical framework to study single-photon emission from color centers in diamond under electrical pumping. The proposed model comprises electron and hole trapping and releasing, transitions between the ground and excited states of the color center as well as structural transformations of the center due to carrier trapping. It provides the possibility to predict both the photon emission rate and the wavelength of emitted photons. Self-consistent numerical simulations of the single-photon emitting diode based on the proposed model show that the photon emission rate can be as high as 100 kcounts s‑1 at standard conditions. In contrast to most optoelectronic devices, the emission rate steadily increases with the device temperature achieving of more than 100 Mcount s‑1 at 500 K, which is highly advantageous for practical applications. These results demonstrate the potential of color centers in diamond as electrically driven non-classical light emitters and provide a foundation for the design and development of single-photon sources for optical quantum computation and quantum communication networks operating at room and higher temperatures.

  4. Ultrabright single-photon source on diamond with electrical pumping at room and high temperatures

    Science.gov (United States)

    Fedyanin, D. Yu; Agio, M.

    2016-07-01

    The recently demonstrated electroluminescence of color centers in diamond makes them one of the best candidates for room temperature single-photon sources. However, the reported emission rates are far off what can be achieved by state-of-the-art electrically driven epitaxial quantum dots. Since the electroluminescence mechanism has not yet been elucidated, it is not clear to what extent the emission rate can be increased. Here we develop a theoretical framework to study single-photon emission from color centers in diamond under electrical pumping. The proposed model comprises electron and hole trapping and releasing, transitions between the ground and excited states of the color center as well as structural transformations of the center due to carrier trapping. It provides the possibility to predict both the photon emission rate and the wavelength of emitted photons. Self-consistent numerical simulations of the single-photon emitting diode based on the proposed model show that the photon emission rate can be as high as 100 kcounts s-1 at standard conditions. In contrast to most optoelectronic devices, the emission rate steadily increases with the device temperature achieving of more than 100 Mcount s-1 at 500 K, which is highly advantageous for practical applications. These results demonstrate the potential of color centers in diamond as electrically driven non-classical light emitters and provide a foundation for the design and development of single-photon sources for optical quantum computation and quantum communication networks operating at room and higher temperatures.

  5. Looking at single photons using hybrid detectors

    Science.gov (United States)

    Bergamaschi, A.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Jungmann-Smith, J. H.; Mezza, D.; Mozzanica, A.; Schmitt, B.; Shi, X.; Tinti, G.

    2015-01-01

    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 μm pitch MÖNCH and the 75 μm 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.

  6. Multidimensional time-correlated single photon counting

    Science.gov (United States)

    Becker, Wolfgang; Bergmann, Axel

    2006-10-01

    Time-correlated single photon counting (TCSPC) is based on the detection of single photons of a periodic light signal, measurement of the detection time of the photons, and the build-up of the photon distribution versus the time in the signal period. TCSPC achieves a near ideal counting efficiency and transit-time-spread-limited time resolution for a given detector. The drawback of traditional TCSPC is the low count rate, long acquisition time, and the fact that the technique is one-dimensional, i.e. limited to the recording of the pulse shape of light signals. We present an advanced TCSPC technique featuring multi-dimensional photon acquisition and a count rate close to the capability of currently available detectors. The technique is able to acquire photon distributions versus wavelength, spatial coordinates, and the time on the ps scale, and to record fast changes in the fluorescence lifetime and fluorescence intensity of a sample. Biomedical applications of advanced TCSPC techniques are time-domain optical tomography, recording of transient phenomena in biological systems, spectrally resolved fluorescence lifetime imaging, FRET experiments in living cells, and the investigation of dye-protein complexes by fluorescence correlation spectroscopy. We demonstrate the potential of the technique for selected applications.

  7. InP/(Al,Ga)InP quantum dots on GaAs- and Si-substrates for single-photon generation at elevated temperatures

    OpenAIRE

    Bommer, Moritz

    2013-01-01

    This work concentrates on optical investigation on single-photon generation for applications in communications, quantum cryptography, and quantum computing. Single-photon sources for commercial devices require robustness in their working conditions, e.g. temperature, pressure, etc. as well as high output rates and emission directionality. From the many possibilities of generating single-photons like single-atoms, parametric down-conversion, nitrogen vacancy centers in diamond etc., InP quantu...

  8. 单光子发射型CT检测抑郁症患者局部脑血流的变化%Changes of regional cerebral blood flow in patients with depressive disorder detected by single photon emission computerized tomography

    Institute of Scientific and Technical Information of China (English)

    江旭峰; 李培勇; 张剑戈; 陈刚; 于金玲; 李彪; 朱承谟

    2006-01-01

    BACKGROUND: Decrease of regional cerebral blood flow (rCBF) perfusion of different degree exists in depressive patients, but the decreased ranges were different, different cerebral cortical and subcortical regions are involved.OBJECTIVE: To observe the types of abnormal rCBF perfusion in patients with depressive disorder.DESIGN: A diagnosis-based case-control analysis.SETTINGS: Department of Nuclear Medicine, Ruijin Hospital Affiliated to the Medical College of Shanghai Jiaotong University; Staff Room of Biomedical Engineering, Medical College of Shanghai Jiaotong University;Putuo District Mental Health of Shanghai City.PARTICIPANTS: The patients with depressive disorder were selected from the Putuo District Mental Health Center from January 1999 to December 2000, and 19 normal subjects matched by age were selected from the medical staff of the hospital as normal controls.METHODS: The patients with depressive disorder and healthy subjects were examined by single photon emission computerized tomography (SPECT), ethyl cysteinate dimmer (99Tcm-ECD) was performed, and the images were analyzed with the statistical parametric mapping (SPM). All the SPECT images were converted into DICOM format or ANALYZE-7 format at first, and then the images were standardized by taking MRI template as the template and smoothed, and the significantly different regions were evaluated by the statistical analysis and inferences with the Gaussian random theory.MAIN OUTCOME MEASURES: The differences of the cerebral blood flow perfusion in specific region and the changes of average rCBF images were mainly observed in the depressive disorder group and normal control group.RESULTS: All the 12 patients with depressive disorder and 19 normal healthy subjects entered the analysis of results. The SPM showed that the blood flow perfusion was decreased in bilateral frontal lobes, left superior temporal gyrus, left Brodmann area 20, left mamillary body of thalamus,right cingulated gyrus and right

  9. High-quality asynchronous heralded single-photon source at telecom wavelength

    International Nuclear Information System (INIS)

    We report on the experimental realization and characterization of an asynchronous heralded single-photon source based on spontaneous parametric down-conversion. Photons at 1550 nm are heralded as being inside a single-mode fibre with more than 60% probability, and the multi-photon emission probability is reduced by a factor of up to more than 500 compared to Poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons, are compatible with practical applications needing very efficient and robust single-photon sources

  10. Near-unity efficiency, single-photon sources based on tapered photonic nanowires

    DEFF Research Database (Denmark)

    Bleuse, Joël; Munsch, Mathieu; Claudon, Julien;

    2012-01-01

    Single-photon emission from excitons in InAs Quantum Dots (QD) embedded in GaAs Tapered Photonic Wires (TPW) already demonstrated a 0.72 collection efficiency, with TPWs were the apex is the sharp end of the cone. Going to alternate designs, still based on the idea of the adiabatic deconfinement ...

  11. High-efficiency single-photon source: The photonic wire geometry

    DEFF Research Database (Denmark)

    Claudon, J.; Bazin, Maela; Malik, Nitin S.;

    2009-01-01

    We present a single-photon-source design based on the emission of a quantum dot embedded in a semiconductor (GaAs) nanowire. The nanowire ends are engineered (efficient metallic mirror and tip taper) to reach a predicted record-high collection efficiency of 90% with a realistic design. Preliminar...

  12. Generating single photons at gigahertz modulation-speed using electrically controlled quantum dot microlenses

    Energy Technology Data Exchange (ETDEWEB)

    Schlehahn, A.; Schmidt, R.; Hopfmann, C.; Schulze, J.-H.; Strittmatter, A.; Heindel, T., E-mail: tobias.heindel@tu-berlin.de; Reitzenstein, S. [Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin (Germany); Gantz, L.; Schmidgall, E. R.; Gershoni, D. [The Physics Department and the Solid State Institute, Technion-Israel Institute of Technology, 32000 Haifa (Israel)

    2016-01-11

    We report on the generation of single-photon pulse trains at a repetition rate of up to 1 GHz. We achieve this speed by modulating the external voltage applied on an electrically contacted quantum dot microlens, which is optically excited by a continuous-wave laser. By modulating the photoluminescence of the quantum dot microlens using a square-wave voltage, single-photon emission is triggered with a response time as short as (281 ± 19) ps, being 6 times faster than the radiative lifetime of (1.75 ± 0.02) ns. This large reduction in the characteristic emission time is enabled by a rapid capacitive gating of emission from the quantum dot, which is placed in the intrinsic region of a p-i-n-junction biased below the onset of electroluminescence. Here, since our circuit acts as a rectifying differentiator, the rising edge of the applied voltage pulses triggers the emission of single photons from the optically excited quantum dot. The non-classical nature of the photon pulse train generated at GHz-speed is proven by intensity autocorrelation measurements with g{sup (2)}(0) = 0.3 ± 0.1. Our results combine optical excitation with fast electrical gating and thus show promise for the generation of indistinguishable single photons at rates exceeding the limitations set by the intrinsic radiative lifetime.

  13. Electromagnetic fields, size, and copy of a single photon

    CERN Document Server

    Liu, Shan-Liang

    2016-01-01

    We propose the expressions of electromagnetic fields of a single photon which properly describe the known characteristics of a photon, derive the relations between the photon size and wavelength on basis of the expressions, reveal the differences between a photon and its copy, and give the specific expressions of annihilation and creation operators of a photon. The results show that a photon has length of half the wavelength, and its radius is proportional to square root of the wavelength; a photon and its copy have the phase difference of {\\pi} and constitute a phase-entangled state; the N-photon phase-entangled state, which is formed by the sequential stimulated emission and corresponds to the wave train in optics, is not a coherent state, but it is the eigenstate of the number operator of photons.

  14. 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

  15. Circuit electromechanics with single photon strong coupling

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Zheng-Yuan, E-mail: zyxue@scnu.edu.cn; Yang, Li-Na [Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Zhou, Jian, E-mail: jianzhou8627@163.com [Department of Electronic Communication Engineering, Anhui Xinhua University, Hefei 230088 (China); Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, and School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2015-07-13

    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.

  16. Multimode theory of single-photon subtraction

    Science.gov (United States)

    Averchenko, V.; Jacquard, C.; Thiel, V.; Fabre, C.; Treps, N.

    2016-08-01

    We develop a general theory to describe the manipulation of a multimode quantum state of light via the subtraction of a single photon. The theory is applicable for various types of subtraction schemes independent of the physical nature of the light modes, their number or the embedded quantum states. We show that different subtraction schemes can be described in a unified approach through the characterization of their intrinsic subtraction modes. The conditional state of the multimode quantum light after the photon subtraction is defined by the number of subtraction modes and their matching with the light modes. We propose the manipulation of light states by controlling the subtraction modes. Performing a photon subtraction on a multimode quantum resource is promising for the implementation of a number of quantum information protocols in all-optical, multiplexed and scalable way.

  17. Atomic metasurfaces for manipulation of single photons

    CERN Document Server

    Zhou, Ming; Kats, Mikhail; Yu, Zongfu

    2016-01-01

    Metasurfaces are an emerging platform for the manipulation of light on a two-dimensional plane. Existing metasurfaces comprise arrays of optical resonators such as plasmonic antennas or high-index nanoparticles. In this letter, we describe a new type of metasurface based on electronic transitions in two-level systems (TLSs). Specifically, we investigated a sheet of rubidium (Rb) atoms, whose energy levels can be tuned with structured illumination from a control laser, which enables dynamically tunable single-photon steering. These metasurface elements are lossless and orders of magnitude smaller than conventional optical resonators, which allows for the overlapping of multiple metasurfaces in a single plane, enabling multi-band operation. We demonstrate that atomic metasurfaces can be passive optical elements, and can also be utilized for beaming of spontaneously emitted photons. Though conceptually similar to conventional metasurfaces, the use of TLSs, which are inherently Fermionic, will lead to numerous ne...

  18. Circuit electromechanics with single photon strong coupling

    International Nuclear Information System (INIS)

    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

  19. Shaping single photons and biphotons by inherent losses

    Science.gov (United States)

    Su, Wei-Ming; Chinnarasu, Ravikumar; Kuo, Chang-Hau; Chuu, Chih-Sung

    2016-09-01

    Inherent loss is always to be avoided in generating single photons or biphotons, but interestingly it provides opportunities for manipulating the photon wave packet. In this paper we show how inherent loss in parametric down-conversion can be employed to tailor the wave packets of single photons and biphotons. As an example, we propose a scheme to realize a single photon in a single cycle using inherent loss. Our work has potential applications in quantum communication, quantum computation, and quantum interface.

  20. Near-infrared single-photon spectroscopy of a whispering gallery mode resonator using energy-resolving transition edge sensors

    CERN Document Server

    Förtsch, Michael; Stevens, Martin J; Strekalov, Dmitry; Schunk, Gerhard; Fürst, Josef U; Vogl, Ulrich; Sedlmeir, Florian; Schwefel, Harald G L; Leuchs, Gerd; Nam, Sae Woo; Marquardt, Christoph

    2014-01-01

    We demonstrate a method to perform spectroscopy of near-infrared single photons without the need of dispersive elements. This method is based on a photon energy resolving transition edge sensor and is applied for the characterization of widely wavelength tunable narrow-band single photons emitted from a crystalline whispering gallery mode resonator. We measure the emission wavelength of the generated signal and idler photons with an uncertainty of up to 2 nm.

  1. Generation and Detection of Infrared Single Photons and their Applications

    Institute of Scientific and Technical Information of China (English)

    ZENG He-ping; WU Guang; WU E; PAN Hai-feng; ZHOU Chun-yuan; WU E.,F.Treussart; J.-F.Roch

    2006-01-01

    Unbreakable secret communication has been a dream from ancient time.It is quantum physics that gives us hope to turn this wizardly dream into reality.The rapid development of quantum cryptography may put an end to the history of eavesdropping.This will be largely due to the advanced techniques related to single quanta,especially infrared single photons.In this paper,we report on our research works on single-photon control for quantum cryptography,ranging from single-photon generation to single-photon detection and their applications.

  2. Prostate cancer and abdomino-pelvic masses with {sup 99m}Tc-HDP uptake. Contribution of the single photon emission computerized tomography guided by computerized tomography (SPECT/CT); Cancer de la prostate et masses abdominopelviennes fixant le {sup 99m}Tc-HDP. Apport de la tomographie d'emission monophotonique couplee a la tomodensitometrie (TEMP-TDM)

    Energy Technology Data Exchange (ETDEWEB)

    Granier, P.; Mourad, M. [Centre Hospitalier Antoine-Gayraud, Service de Medecine Nucleaire, 11 - Carcassonne (France)

    2009-06-15

    We report the case of a 63-year-old man, investigated for staging of a prostatic cancer, diagnosed by biopsy, following a rise in the prostatic specific antigen (P.S.A.) on a systematic assessment. The interrogation before examination revealed signs of beginning right crural neuropathy. The hydroxy-methylene diphosphonate technetium 99 m-labeled ({sup 99m}Tc-H.D.P.) whole-body bone scintigraphy highlighted two extraosseous uptake images, the first of moderated intensity in the right iliac area, the second milder, in the abdominal median area. Osseous metastases were not visualized. The single photon emission computerized tomography guided by computerized tomography (SPECT/CT) identified the median abdominal mass which corresponded to a bulky aneurysm of the under renal abdominal aorta. The right iliac mass could be accurately analyzed and differentiated from the various organs of the abdomino-pelvic cavity. Its lymphatic origin was hypothesized, but the diagnosis of lymphatic metastasis of the prostatic cancer was obtained by the pathologic examination of CT scan-guided biopsy. (authors)

  3. A single photon emission computed tomograph based on a limited dumber of detectors for fluid flow visualization; Tomographie d'emission gamma a partir d'un nombre limite de detecteurs appliquee a la visualisation d'ecoulements

    Energy Technology Data Exchange (ETDEWEB)

    Legoupil, S

    1999-07-01

    We present in this work a method for fluid flow visualization in a system using radioactive tracers. The method is based on single photon emission computed tomography techniques, applied to a limited number of discrete detectors. We propose in this work a method for the estimation of the transport matrix of photons, associated to the acquisition system.This method is based on the modelization of profiles acquired for a set of point sources located in the imaged volume. Monte Carlo simulations allow to separate scattered photons from those directly collected by the system. The influence of the energy tracer is exposed. The reconstruction method is based on the maximum likelihood - expectation maximization algorithm. An experimental device, based on 36 detectors was realised for the visualization of water circulation in a vessel. A video monitoring allows to visualize the dye water tracer. Dye and radioactive tracers are injected simultaneously in a water flow circulating in the vessel. Reconstructed and video images are compared. Quantitative and qualitative analysis show that fluid flow visualization is feasible with a limited number of detectors. This method can be applied for system involving circulations of fluids. (author)

  4. Quantum Communication with Continuum Single-Photon Pulses

    OpenAIRE

    Rios, F. F. S.; Ramos, R. V.

    2014-01-01

    In this work, we analyze the behavior of continuum single-photon pulses in some quantum communication schemes. In particular, we consider the single-photon interference in a Mach-Zenhder interferometer, the HOM interference and the quantum bit commitment protocol.

  5. Single-photon imaging in complementary metal oxide semiconductor processes

    NARCIS (Netherlands)

    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 senso

  6. Characterization of APDs for single photon counting

    Energy Technology Data Exchange (ETDEWEB)

    Buglak, Wladimir; Hannen, Volker; Joehren, Raphael; Surholt, Martin; Vollbrecht, Jonas; Weinheimer, Christian [Muenster Univ. (Germany). Inst. fuer Kernphysik; Noertershaeuser, Wilfried [Mainz Univ. (Germany). Inst. fuer Kernchemie; GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Sanchez, Rodolfo [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2013-07-01

    For the SPECTRAP experiment at GSI, Germany, a detector system with single-photon counting capability operating in the wavelength region from 300 nm up to 1100 nm has been developed at the University of Muenster. The detector system utilises a silicon avalanche photo diode (APD) cooled to liquid nitrogen temperatures and operated near the breakdown voltage to obtain high gain values. While the current setup uses a 2 x 2 mm{sup 2} APD (type RMD S0223), it would be advantageous to have a larger active area for easier adjustment of the experiment optics. On the other hand a larger active area is accompanied by increased thermal noise which might harm the photon counting performance of the device. The characterization of a 8 x 8 mm{sup 2} APD (RMD S0814) is the subject of this poster. Furthermore a signal analysis software was developed to supress noise signals, e.g. caused by microphonic effects. The software processes signal waveforms recorded by a Flash ADC and should allow for a lower trigger threshold and thus higher detection efficiency.

  7. 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...

  8. Single-photon absorber based on strongly interacting Rydberg atoms

    CERN Document Server

    Tresp, Christoph; Mirgorodskiy, Ivan; Gorniaczyk, Hannes; Paris-Mandoki, Asaf; Hofferberth, Sebastian

    2016-01-01

    Removing exactly one photon from an arbitrary input pulse is an elementary operation in quantum optics and enables applications in quantum information processing and quantum simulation. Here we demonstrate a deterministic single-photon absorber based on the saturation of an optically thick free-space medium by a single photon due to Rydberg blockade. Single-photon subtraction adds a new component to the Rydberg quantum optics toolbox, which already contains photonic logic building-blocks such as single-photon sources, switches, transistors, and conditional $\\pi$-phase shifts. Our approach is scalable to multiple cascaded absorbers, essential for preparation of non-classical light states for quantum information and metrology applications, and, in combination with the single-photon transistor, high-fidelity number-resolved photon detection.

  9. Photon Statistics of Single-Photon Quantum States in Real Single Photon Detection

    Institute of Scientific and Technical Information of China (English)

    李刚; 李园; 王军民; 彭堃墀; 张天才

    2004-01-01

    @@ Single photon detection (SPD) with high quantum efficiency has been widely used for measurement of different quantum states with different photon distributions.Based on the direct single SPD and double-SPD of HBT configuration, we discuss the effect of a real SPD on the photon statistics measurement and it shows that the measured photon distributions for different quantum states are corrected in different forms.The results are confirmed by experiment with the strongly attenuated coherent light and thermal light.This system can be used to characterize the photon statistics of the fluorescence light from single atom or single molecular.

  10. Quantum Transduction of Telecommunications-band Single Photons from a Quantum Dot by Frequency Upconversion

    CERN Document Server

    Rakher, Matthew T; Slattery, Oliver; Tang, Xiao; Srinivasan, Kartik

    2010-01-01

    The ability to transduce non-classical states of light from one wavelength to another is a requirement for integrating disparate quantum systems that take advantage of telecommunications-band photons for optical fiber transmission of quantum information and near-visible, stationary systems for manipulation and storage. In addition, transducing a single-photon source at 1.3 {\\mu}m to visible wavelengths for detection would be integral to linear optical quantum computation due to the challenges of detection in the nearinfrared. Recently, transduction at single-photon power levels has been accomplished through frequency upconversion, but it has yet to be demonstrated for a true single-photon source. Here, we transduce the triggered single-photon emission of a semiconductor quantum dot at 1.3 {\\mu}m to 710 nm with a total detection (internal conversion) efficiency of 21% (75%). We demonstrate that the 710 nm signal maintains the quantum character of the 1.3 {\\mu}m signal, yielding a photon anti-bunched second-ord...

  11. An integral gated mode single photon detector at telecom wavelengths

    International Nuclear Information System (INIS)

    We demonstrate an integral gated mode single photon detector at telecom wavelengths. The charge number of an avalanche pulse rather than the peak current is monitored for single photon detection. The transient spikes in conventional gated mode operation are cancelled completely by integrating, which enables one to effectively improve the performance of single photon detector with the same avalanche photodiode. This method achieved a detection efficiency of 29.9% at the dark count probability per gate equal to 5.57 x 10-6/gate (1.11 x 10-6 ns-1) at 1550 nm

  12. Quantum Overloading Cryptography Using Single-Photon Nonlocality

    Institute of Scientific and Technical Information of China (English)

    TAN Yong-Gang; CAI Qing-Yu; SHI Ting-Yun

    2007-01-01

    @@ Using the single-photon nonlocality, we propose a quantum novel overloading cryptography scheme, in which a single photon carries two bits information in one-way quantum channel. Two commutative modes of the single photon, the polarization mode and the spatial mode, are used to encode secret information. Strict time windows are set to detect the impersonation attack. The spatial mode which denotes the existence of photons is noncommutative with the phase of the photon, so that our scheme is secure against photon-number-splitting attack. Our protocol may be secure against individual attack.

  13. 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.

  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. Extraction of a single photon from an optical pulse

    Science.gov (United States)

    Rosenblum, Serge; Bechler, Orel; Shomroni, Itay; Lovsky, Yulia; Guendelman, Gabriel; Dayan, Barak

    2016-01-01

    Removing a single photon from a pulse is one of the most elementary operations that can be performed on light, having both fundamental significance and practical applications in quantum communication and computation. So far, photon subtraction, in which the removed photon is detected and therefore irreversibly lost, has been implemented in a probabilistic manner with inherently low success rates using low-reflectivity beam splitters. Here we demonstrate a scheme for the deterministic extraction of a single photon from an incoming pulse. The removed photon is diverted to a different mode, enabling its use for other purposes, such as a photon number-splitting attack on quantum key distribution protocols. Our implementation makes use of single-photon Raman interaction (SPRINT) with a single atom near a nanofibre-coupled microresonator. The single-photon extraction probability in our current realization is limited mostly by linear loss, yet probabilities close to unity should be attainable with realistic experimental parameters.

  16. Correction of ultraviolet single photon counting image distortion

    Institute of Scientific and Technical Information of China (English)

    Xinghua Zhang; Baosheng Zhao; Zhenhua Miao; Wei Li; Xiangping Zhu; Yong'an Liu; Wei Zou

    2008-01-01

    Single photon counting imaging technology has been widely used in space environment detection, astronomy observation, nuclear physics, and ultraweak bioluminescence. However, the distortion of the single photon counting image will badly affect the measurement results. Therefore, the correction of distortion for single photon counting image is very significant. Ultraviolet single photon imaging system with wedge and strip anode is introduced and the influence factor leading to image distortion is analyzed. To correct original distorted image, three different image correction methods, namely, the physical correction, the global correction, and the local correction, are applied. In addition, two parameters, i.e, the position index and the linearity index, are defined to evaluate the performance of the three methods. The results suggest that the correction methods can improve the quality of the initial image without losing gray information of each counting light spot. And the local correction can provide the best visual inspections and performance evaluation among the three methods.

  17. Category theoretic analysis of single-photon decision maker

    CERN Document Server

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

    2016-01-01

    Decision making is a vital function in the era of artificial intelligence; however, its physical realizations and their theoretical fundamentals are not yet known. In our former study [Sci. Rep. 5, 513253 (2015)], we demonstrated that single photons can be used to make decisions in uncertain, dynamically changing environments. The multi-armed bandit problem was successfully solved using the dual probabilistic and particle attributes of single photons. Herein, we present the category theoretic foundation of the single-photon-based decision making, including quantitative analysis that agrees well with the experimental results. The category theoretic model unveils complex interdependencies of the entities of the subject matter in the most simplified manner, including a dynamically changing environment. In particular, the octahedral structure in triangulated categories provides a clear understanding of the underlying mechanisms of the single-photon decision maker. This is the first demonstration of a category the...

  18. The analysis of the integral gated mode single photon detector

    Institute of Scientific and Technical Information of China (English)

    Wei Zheng-Jun; Li Kai-Zhen; Zhou Peng; Wang Jin-Dong; Liao Chang-Jun; Guo Jian-Ping; Liang Rui-Sheng; Liu Song-Hao

    2008-01-01

    This paper critically analyses and simulates the circuit configuration of the integral gated mode single photon detector which is proposed for eliminating the transient spikes problem of conventional gated mode single photon detector.The relationship between the values of the circuit elements and the effect of transient spikes cancellation has been obtained.With particular emphasis,the bias voltage of the avalanche photodiode and the output signal voltage of the integrator have been calculated.The obtained analysis results indicate that the output signal voltage of the integrator only relates to the total quantity of electricity of the avalanche charges by choosing the correct values of the circuit elements and integral time interval.These results can be used to optimize the performance of single photon detectors and provide guides for the design of single photon detectors.

  19. A Versatile Source of Single Photons for Quantum Information Processing

    CERN Document Server

    Förtsch, Michael; Wittmann, Christoffer; Strekalov, Dmitry; Aiello, Andrea; Chekhova, Maria V; Silberhorn, Christine; Leuchs, Gerd; Marquardt, Christoph

    2012-01-01

    The quantum state of a single photon stands amongst the most fundamental and intriguing manifestations of quantum physics. At the same time single photons and pairs of single photons are important building blocks in the fields of linear optical based quantum computation and quantum repeater infrastructure. These fields possess enormous potential and much scientific and technological progress has been made in developing individual components, like quantum memories and photon sources using various physical implementations. However, further progress suffers from the lack of compatibility between these different components. Ultimately, one aims for a versatile source of single photons and photon pairs in order to overcome this hurdle of incompatibility. Such a photon source should allow for tuning of the spectral properties (wide wavelength range and narrow bandwidth) to address different implementations while retaining high efficiency. In addition, it should be able to bridge different wavelength regimes to make...

  20. Coupling and single-photon purity of a quantum dot-cavity system studied using hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, P. Y.; Wu, X. F.; Ding, K.; Dou, X. M.; Zha, G. W.; Ni, H. Q.; Niu, Z. C.; Zhu, H. J.; Jiang, D. S. [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhao, C. L. [College of Physics and Electronic Information, Inner Mongolia University for Nationalities, Tongliao 028043 (China); Sun, B. Q., E-mail: bqsun@semi.ac.cn [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); College of Physics and Electronic Information, Inner Mongolia University for Nationalities, Tongliao 028043 (China)

    2015-01-07

    We propose an approach to tune the emission of a single semiconductor quantum dot (QD) to couple with a planar cavity using hydrostatic pressure without inducing temperature variation during the process of measurement. Based on this approach, we studied the influence of cavity mode on the single-photon purity of an InAs/GaAs QD. Our measurement demonstrates that the single-photon purity degrades when the QD emission resonates with the cavity mode. This negative influence of the planar cavity is mainly caused by the cavity feeding effect.

  1. Reach of Environmental Influences on the Indistinguishability of Single Photons from Quantum Dots

    CERN Document Server

    Huber, Tobias; Föger, Daniel; Solomon, Glenn; Weihs, Gregor

    2015-01-01

    In this letter, we present a detailed, all optical study of the influence of different excitation schemes on the indistinguishability of single photons from a single InAs quantum dot. For this study, we measure the Hong-Ou-Mandel interference of consecutive photons from the spontaneous emission of an InAs quantum dot state under various excitation schemes and different excitation conditions and give a comparison.

  2. Single photon, spin, and charge manipulation of diamond quantum register

    International Nuclear Information System (INIS)

    Single-photon sources that provide non-classical light states on demand have a broad range of application in quantum communication, quantum computing, and metrology. Recently, significant progresses have been shown in semiconductor quantum-dots. However, a major obstacle is the requirement of cryogenic temperatures. Here we show the realization of a stable room temperature electrically driven single-photon source based on a single NV centre in a diode structure. (author)

  3. Higgs boson decays into single photon plus unparticle

    International Nuclear Information System (INIS)

    The decay of the standard model Higgs boson into a single photon and a vector unparticle through a one-loop process is studied. For an intermediate-mass Higgs boson, this single photon plus unparticle mode can have a branching ratio comparable with the two-photon discovery mode. The emitted photon has a continuous energy spectrum encoding the nature of the recoil unparticle. It can be measured in precision studies of the Higgs boson after its discovery.

  4. 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).

  5. Photon statistics characterization of a single photon source

    OpenAIRE

    Alleaume, Romain; Treussart, Francois; Courty, Jean-Michel; Roch, Jean-Francois

    2003-01-01

    n a recent experiment, we reported the time-domain intensity noise measurement of a single photon source relying on single molecule fluorescence control. In this article 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 ONOFF dynamics . Finally, source intensity noise analysis using the Mandel parameter is quantitatively compared to the usual...

  6. Quasi-secure quantum dialogue using single photons

    Institute of Scientific and Technical Information of China (English)

    YANG; YuGuang; WEN; QiaoYan

    2007-01-01

    A quasi-secure quantum dialogue protocol using single photons was proposed. Different from the previous entanglement-based protocols, the present protocol uses batches of single photons which run back and forth between the two parties. A round run for each photon makes the two parties each obtain a classical bit of information. So the efficiency of information transmission can be increased. The present scheme is practical and well within the present-day technology.

  7. Experimental generation of single photons via active multiplexing

    International Nuclear Information System (INIS)

    An on-demand single-photon source is a fundamental building block in quantum science and technology. We experimentally demonstrate the proof of concept for a scheme to generate on-demand single photons via actively multiplexing several heralded photons probabilistically produced from pulsed spontaneous parametric down-conversions (SPDCs). By utilizing a four-photon-pair source, an active feed-forward technique, and an ultrafast single-photon router, we show a fourfold enhancement of the output photon rate. Simultaneously, we maintain the quality of the output single-photon states, confirmed by correlation measurements. We also experimentally verify, via Hong-Ou-Mandel interference, that the router does not affect the indistinguishability of the single photons. Furthermore, we give numerical simulations, which indicate that photons based on multiplexing of four SPDC sources can outperform the heralding based on highly advanced photon-number-resolving detectors. Our results show a route for on-demand single-photon generation and the practical realization of scalable linear optical quantum-information processing.

  8. Brain SPECT with Tl-201 DDC

    International Nuclear Information System (INIS)

    The development, animal and human experiments and the first clinical results of a new blood flow tracer thallium-201 diethyldithiocarbamate (Tl-201 DDC) are discussed for functional brain imaging with single-photon emission computed tomography (SPECT). 325 refs.; 43 figs.; 22 tabs

  9. Mapping human brain activity in vivo.

    OpenAIRE

    Mazziotta, J.C.

    1994-01-01

    A wide range of structural and functional techniques now exists to map the human brain in health and disease. These approaches span the gamut from external tomographic imaging devices (positron-emission tomography, single photon-emission computed tomography, magnetic resonance imaging, computed tomography), to surface detectors (electroencephalography, magnetoencephalography, transcranial magnetic stimulation), to measurements made directly on the brain's surface or beneath it (intrinsic sign...

  10. Bright and stable visible-spectrum single photon emitter in silicon carbide

    CERN Document Server

    Lienhard, Benjamin; Mouradian, Sara; Dolde, Florian; Tran, Toan Trong; Aharonovich, Igor; Englund, Dirk R

    2016-01-01

    Single photon sources are of paramount importance in quantum communication, quantum computation, and quantum metrology. In particular, there is great interest to realize scalable solid state platforms that can emit triggered photons on demand to achieve scalable nanophotonic networks. We report on a visible-spectrum single photon emitter in 4H-silicon carbide (SiC). The emitter is photostable at room- and low-temperature enabling photon counts per second (cps) in excess of 2$\\times$10$^6$ from unpatterned, bulk SiC. It exists in two orthogonally polarized states, which have parallel absorption and emission dipole orientations. Low temperature measurements reveal a narrow zero phonon line (linewidth $30~$% of the total photoluminescence spectrum.

  11. Downconversion quantum interface for a single quantum dot spin and 1550-nm single-photon channel

    CERN Document Server

    Pelc, Jason S; De Greve, Kristiaan; McMahon, Peter L; Natarajan, Chandra M; Esfandyarpour, Vahid; Maier, Sebastian; Schneider, Christian; Kamp, Martin; Höfling, Sven; Hadfield, Robert H; Forchel, Alfred; Yamamoto, Yoshihisa; Fejer, M M

    2012-01-01

    Long-distance quantum communication networks require appropriate interfaces between matter qubit-based nodes and low-loss photonic quantum channels. We implement a downconversion quantum interface, where the single photons emitted from a semiconductor quantum dot at 910 nm are downconverted to 1560 nm using a fiber-coupled periodically poled lithium niobate waveguide and a 2.2-$\\mu$m pulsed pump laser. The single-photon character of the quantum dot emission is preserved during the downconversion process: we measure a cross-correlation $g^{(2)}(\\tau = 0) = 0.17$ using resonant excitation of the quantum dot. We show that the downconversion interface is fully compatible with coherent optical control of the quantum dot electron spin through the observation of Rabi oscillations in the downconverted photon counts. These results represent a critical step towards a long-distance hybrid quantum network in which subsystems operating at different wavelengths are connected through quantum frequency conversion devices and...

  12. Bright single photon source based on self-aligned quantum dot-cavity systems.

    Science.gov (United States)

    Maier, Sebastian; Gold, Peter; Forchel, Alfred; Gregersen, Niels; Mørk, Jesper; Höfling, Sven; Schneider, Christian; Kamp, Martin

    2014-04-01

    We report on a quasi-planar quantum-dot-based single-photon source that shows an unprecedented high extraction efficiency of 42% without complex photonic resonator geometries or post-growth nanofabrication. This very high efficiency originates from the coupling of the photons emitted by a quantum dot to a Gaussian shaped nanohill defect that naturally arises during epitaxial growth in a self-aligned manner. We investigate the morphology of these defects and characterize the photonic operation mechanism. Our results show that these naturally arising coupled quantum dot-defects provide a new avenue for efficient (up to 42% demonstrated) and pure (g(2)(0) value of 0.023) single-photon emission. PMID:24718190

  13. A high-temperature single-photon source from nanowire quantum dots.

    Science.gov (United States)

    Tribu, Adrien; Sallen, Gregory; Aichele, Thomas; André, Régis; Poizat, Jean-Philippe; Bougerol, Catherine; Tatarenko, Serge; Kheng, Kuntheak

    2008-12-01

    We present a high-temperature single-photon source based on a quantum dot inside a nanowire. The nanowires were grown by molecular beam epitaxy in the vapor-liquid-solid growth mode. We utilize a two-step process that allows a thin, defect-free ZnSe nanowire to grow on top of a broader, cone-shaped nanowire. Quantum dots are formed by incorporating a narrow zone of CdSe into the nanowire. We observe intense and highly polarized photoluminescence even from a single emitter. Efficient photon antibunching is observed up to 220 K, while conserving a normalized antibunching dip of at most 36%. This is the highest reported temperature for single-photon emission from a nonblinking quantum-dot source and principally allows compact and cheap operation by using Peltier cooling.

  14. Regional cerebral blood flow in aged diabetic patients without a history of cerebrovascular accident, determined by N-isopropyl- sup 123 I-p-iodoamphetamine with single photon emission CT

    Energy Technology Data Exchange (ETDEWEB)

    Wakisaka, Masanori; Nagamachi, Shigeki; Inoue, Kenjiro; Morotomi, Yasuyuki (National Sanatorium Miyazaki Higashi Hospital (Japan)); Nunoi, Kiyohide; Fujishima, Masatoshi

    1989-07-01

    N-isopropyl-{sup 123}I-p-iodoamphetamine (IMP) was used to determine the regional cerebral blood flow in 9 diabetic patients (average age: 71.8 years) and 9 non-diabetic subjects (average age: 71.7 years), none of whom had a history of cerebrovascular accident. There were no significant differences in the physiological or laboratory data between the diabetic and non-diabetic groups except in fasting plasma glucose and HbA{sub 1}c levels. Areas of hypoperfusion of the cerebral hemispheres were observed in 7 diabetic patients, 5 of whom showed multiple lesions. On the other hand, areas of hypoperfusion were observed only in 4 of the non-diabetic subjects and only 1 of these demonstrated multiple lesions. We evaluated the cerebral blood flow semiquantitatively as follows: the area where the radioactive count was 65% or more of the maximum count of the slice was defined as a region of normal cerebral blood flow (ROI-A); the area where the count was 45% or more as region of brain tissue except for ventricles (RUI-B). The numbers of pixels of ROI-A and ROI-B were counted in each slice and the ROI-A/B ratios of 16 slices were averaged individually. The average percent ROI-A/B ratio was significantly lower in the diabetic group than that in the control group (49.4+-1.9 (Mean+-SEM) vs 56.6+-1.9%, p<0.05). These observations suggest that the area of normal regional cerebral blood flow is reduced in aged diabetics, even in the absence of a history of cerebrovascular accident. (author).

  15. Regional cerebral blood flow in aged diabetic patients without a history of cerebrovascular accident, determined by N-isopropyl-123I-p-iodoamphetamine with single photon emission CT

    International Nuclear Information System (INIS)

    N-isopropyl-123I-p-iodoamphetamine (IMP) was used to determine the regional cerebral blood flow in 9 diabetic patients (average age: 71.8 years) and 9 non-diabetic subjects (average age: 71.7 years), none of whom had a history of cerebrovascular accident. There were no significant differences in the physiological or laboratory data between the diabetic and non-diabetic groups except in fasting plasma glucose and HbA1c levels. Areas of hypoperfusion of the cerebral hemispheres were observed in 7 diabetic patients, 5 of whom showed multiple lesions. On the other hand, areas of hypoperfusion were observed only in 4 of the non-diabetic subjects and only 1 of these demonstrated multiple lesions. We evaluated the cerebral blood flow semiquantitatively as follows: the area where the radioactive count was 65% or more of the maximum count of the slice was defined as a region of normal cerebral blood flow (ROI-A); the area where the count was 45% or more as region of brain tissue except for ventricles (RUI-B). The numbers of pixels of ROI-A and ROI-B were counted in each slice and the ROI-A/B ratios of 16 slices were averaged individually. The average percent ROI-A/B ratio was significantly lower in the diabetic group than that in the control group (49.4±1.9 (Mean±SEM) vs 56.6±1.9%, p<0.05). These observations suggest that the area of normal regional cerebral blood flow is reduced in aged diabetics, even in the absence of a history of cerebrovascular accident. (author)

  16. PET image reconstruction with system matrix based on point spread function derived from single photon incidence response

    CERN Document Server

    Xin, Fan; Ming-Kai, Yun; Xiao-Li, Sun; Xue-Xiang, Cao; Shuang-Quanm, Liu; Pei, Chai; Dao-Wu, Li; Long, Wei

    2014-01-01

    In positron emission tomography (PET) imaging, statistical iterative reconstruction (IR) techniques appear particularly promising since they can provide accurate physical model and geometric system description. The reconstructed image quality mainly depends on the system matrix model which describes the relationship between image space and projection space for the IR method. The system matrix can contain some physics factors of detection such as geometrical component and blurring component. Point spread function (PSF) is generally used to describe the blurring component. This paper proposes an IR method based on the PSF system matrix, which is derived from the single photon incidence response function. More specifically, the gamma photon incidence on a crystal array is simulated by the Monte Carlo (MC) simulation, and then the single photon incidence response functions are obtained. Subsequently, using the single photon incidence response functions, the coincidence blurring factor is acquired according to the...

  17. 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

  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. 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...

  20. Single-photon observables and preparation uncertainty relations

    International Nuclear Information System (INIS)

    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. (paper)

  1. Video recording true single-photon double-slit interference

    Science.gov (United States)

    Aspden, Reuben S.; Padgett, Miles J.; Spalding, Gabriel C.

    2016-09-01

    Commercially available cameras do not have a low-enough dark noise to directly capture double-slit interference at the single photon level. In this work, camera noise levels are significantly reduced by activating the camera only when the presence of a photon has been detected by the independent detection of a time-correlated photon produced via parametric down-conversion. This triggering scheme provides the improvement required for direct video imaging of Young's double-slit experiment with single photons, allowing clarified versions of this foundational demonstration. We present video data of the evolving interference patterns. Also, we introduce variations on this experiment aimed at promoting discussion of the role spatial coherence plays in such a measurement, emphasizing complementary aspects of single-photon measurement and highlighting the roles of transverse position and momentum correlations between down-converted photons, including examples of "ghost" imaging and diffraction.

  2. 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...

  3. Single photon superradiance and cooperative Lamb shift in an optoelectronic device

    CERN Document Server

    Frucci, Giulia; Vasanelli, Angela; Dailly, Baptiste; Todorov, Yanko; Sirtori, Carlo; Beaudoin, Grégoire; Sagnes, Isabelle

    2016-01-01

    Single photon superradiance is a strong enhancement of spontaneous emission appearing when a single excitation is shared between a large number of two-level systems. This enhanced rate can be accompanied by a shift of the emission frequency, the cooperative Lamb shift, issued from the exchange of virtual photons between the emitters. In this work we present a semiconductor optoelectronic device allowing the observation of these two phenomena at room temperature. We demonstrate experimentally and theoretically that plasma oscillations in spatially separated quantum wells interact through real and virtual photon exchange. This gives rise to a superradiant mode displaying a large cooperative Lamb shift.

  4. 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.

  5. Single-photon interference experiment for high schools

    Science.gov (United States)

    Bondani, Maria

    2014-07-01

    We follow the reductio ad absurdum reasoning described in the book "Sneaking a Look at God's Cards" by Giancarlo Ghirardi to demonstrate the wave-particle duality of light in a Mach-Zehnder interferometric setup analog to the conventional Young double-slit experiment. We aim at showing the double nature of light by measuring the existence of interference fringes down to the single-photon level. The setup includes a strongly attenuated laser, polarizing beam splitters, half-waveplates, polarizers and single-photon detectors.

  6. Single-photon transistor in circuit quantum electrodynamics.

    Science.gov (United States)

    Neumeier, Lukas; Leib, Martin; Hartmann, Michael J

    2013-08-01

    We introduce a circuit quantum electrodynamical setup for a "single-photon" transistor. In our approach photons propagate in two open transmission lines that are coupled via two interacting transmon qubits. The interaction is such that no photons are exchanged between the two transmission lines but a single photon in one line can completely block or enable the propagation of photons in the other line. High on-off ratios can be achieved for feasible experimental parameters. Our approach is inherently scalable as all photon pulses can have the same pulse shape and carrier frequency such that output signals of one transistor can be input signals for a consecutive transistor.

  7. Combustion study with synchrotron radiation single photon ionization technique

    Institute of Scientific and Technical Information of China (English)

    YANG Rui; WANG Jing; HUANG Chaoqun; YANG Bin; WEI Lixia; SHAN Xiaobin; SHENG Liusi; ZHANG Yunwu; QI Fei

    2005-01-01

    Here we report a combustion endstation at National Synchrotron Radiation Laboratory (NSRL) and some primary experimental results. Synchrotron radiation can provide the tunable vacuum ultraviolet (VUV) photon with the high intensity and the good collimation. VUV photoionization is a single-photon ionization process. Combined with molecular-beam mass spectrometry (MBMS), the VUV single-photon ionization can be applied to detect the combustion products, especially the intermediates and free radicals produced from combustion process. This method is proved to be a powerful tool for combustion study, which could be helpful for developing combustion kinetic models and understanding the mechanism of combustion reactions.

  8. CMOS-compatible photonic devices for single-photon generation

    Directory of Open Access Journals (Sweden)

    Xiong Chunle

    2016-09-01

    Full Text Available Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal–oxide–semiconductor (CMOS-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

  9. CMOS-compatible photonic devices for single-photon generation

    Science.gov (United States)

    Xiong, Chunle; Bell, Bryn; Eggleton, Benjamin J.

    2016-09-01

    Sources of single photons are one of the key building blocks for quantum photonic technologies such as quantum secure communication and powerful quantum computing. To bring the proof-of-principle demonstration of these technologies from the laboratory to the real world, complementary metal-oxide-semiconductor (CMOS)-compatible photonic chips are highly desirable for photon generation, manipulation, processing and even detection because of their compactness, scalability, robustness, and the potential for integration with electronics. In this paper, we review the development of photonic devices made from materials (e.g., silicon) and processes that are compatible with CMOS fabrication facilities for the generation of single photons.

  10. A view on progress of silicon single-photon avalanche diodes and quenching circuits

    Science.gov (United States)

    Cova, Sergio; Ghioni, Massimo; Zappa, Franco; Rech, Ivan; Gulinatti, Angelo

    2006-10-01

    Silicon Single-Photon Avalanche-Diodes (SPAD) are nowadays considered a solid-state alternative to Photomultiplier Tubes (PMT) in single photon counting (SPC) and time-correlated single photon-counting (TCSPC) over the visible spectral range up to 1 micron wavelength. SPADs implemented in planar epitaxial technology compatible with CMOS circuits offer the typical advantages of microelectronic devices (small size, ruggedness, low voltage and low power, etc.). Furthermore, they have inherently higher photon detection efficiency, since they do not rely on electron emission in vacuum from a photocathode as PMT, but instead on the internal photoelectric effect. However, PMTs offer much wider sensitive area, which greatly simplifies the design of optical systems; they provide position-sensitive photon detection and imaging capability; they attain remarkable performance at high counting rate and offer picosecond timing resolution with Micro-Channel Plate (MCP) models. In order to make SPADs more competitive in a broader range of SPC and TCPC applications it is necessary to face both semiconductor technology issues and circuit design issues, which will be here dealt with. Technology issues will be discussed in the context of two possible approaches: employing a standard industrial high-voltage compatible CMOS technology or developing a dedicated CMOS-compatible technology. Circuit design issues will be discussed taking into account problems arising from conflicting requirements set by various required features, such as fast and efficient avalanche quenching and reset, high resolution photon timing, etc.

  11. Generation of single photons with highly tunable wave shape from a cold atomic quantum memory

    CERN Document Server

    Farrera, Pau; Albrecht, Boris; Ho, Melvyn; Chávez, Matías; Teo, Colin; Sangouard, Nicolas; de Riedmatten, Hugues

    2016-01-01

    We report on a single photon source with highly tunable photon shape based on a cold ensemble of Rubidium atoms. We follow the DLCZ scheme to implement an emissive quantum memory, which can be operated as a photon pair source with controllable delay. We find that the temporal wave shape of the emitted read photon can be precisely controlled by changing the shape of the driving read pulse. We generate photons with temporal durations varying over three orders of magnitude up to 10 {\\mu}s without a significant change of the read-out efficiency. We prove the non-classicality of the emitted photons by measuring their antibunching, showing near single photon behavior at low excitation probabilities. We also show that the photons are emitted in a pure state by measuring unconditional autocorrelation functions. Finally, to demonstrate the usability of the source for realistic applications, we create ultra-long single photons with a rising exponential or doubly peaked wave shape which are important for several quantum...

  12. Theory of single photon on demand from a single molecule source.

    Science.gov (United States)

    He, Yong; Barkai, Eli

    2006-11-21

    We consider the theory of single photon on demand from a two level atom or molecule source. Using optical Bloch equations and the generating function formalism we investigate three approaches to single photon control: (i) the square laser pulse; (ii) the square modulation of absorption frequency; and (iii) the rapid adiabatic following approach investigated in the experiments of Brunel et al., Phys. Rev. Lett., 1999, 83, 2722. We discuss the conditions for obtaining the maximum of the probability of emission of a single photon and a pair of photons, under the constrains of finite field strength and finite interaction time with excitation field. We obtain analytical expression for the probability of emitting zero, one, and two photons for the square pulse, and discuss semi-classical and strongly quantum limiting cases. Numerical results obtained from the generating function formalism are compared with experimental results showing that the two level system approach is suitable for the description of cryogenic temperature single molecules, and that experiments were conducted very close to the optimal conditions.

  13. 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

  14. Single-photon production at the CERN ISR

    International Nuclear Information System (INIS)

    A measurement of single photon production from p-p collisions at ISR energies is presented. A signal comparable to single π0 production is found at large p/sub T/. A study of associated particles favors production dominated by the first-order QCD process of gluon-valence quark production q g → q γ

  15. Potential of semiconductor nanowires for single photon sources

    NARCIS (Netherlands)

    Harmand, J.-C.; Liu, L.; Patriarche, G.; Tchernycheva, M.; Akopian, N.; Perinetti, U.; Zwiller, V.

    2009-01-01

    The catalyst-assisted growth of semiconductor nanowires heterostructures offers a very flexible way to design and fabricate single photon emitters. The nanowires can be positioned by organizing the catalyst prior to growth. Single quantum dots can be formed in the core of single nanowires which can

  16. Quantum interference of independently generated telecom-band single photons

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Monika [Center for Photonic Communication and Computing, Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3112 (United States); Altepeter, Joseph B.; Huang, Yu-Ping; Oza, Neal N. [Center for Photonic Communication and Computing, Department of Electrical Engineering and Computer Science, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3118 (United States); Kumar, Prem [Center for Photonic Communication and Computing, Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3112, USA and Center for Photonic Communication and Computing, Department of Electrical Engineering (United States)

    2014-12-04

    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.

  17. Programming Single-Photon Wavefronts for Quantum Authentication

    NARCIS (Netherlands)

    Pinkse, P.W.H.; Huisman, T.J.; Huisman, S.R.; Wolterink, T.A.W.; Mosk, A.P.

    2014-01-01

    We demonstrate the ability to program the wavefront of single-photon states produced by spontaneous parametric down conversion into complex two-dimensional patterns with a spatial light modulator for application in quantum authentication and quantum communication. © 2014 OSA

  18. Deterministic teleportation using single-photon entanglement as a resource

    DEFF Research Database (Denmark)

    Björk, Gunnar; Laghaout, Amine; Andersen, Ulrik L.

    2012-01-01

    We outline a proof that teleportation with a single particle is, in principle, just as reliable as with two particles. We thereby hope to dispel the skepticism surrounding single-photon entanglement as a valid resource in quantum information. A deterministic Bell-state analyzer is proposed which...

  19. Room temperature mid-IR single photon spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2012-01-01

    room temperature dark noise is 0.2 photons/spatial element/second, which is a billion times below the dark noise level of cryogenically cooled InSb cameras. Single photon imaging and up to 200 x 100 spatial elements resolution is obtained reaching record high continuous wave quantum efficiency of about...

  20. Multiple-Event, Single-Photon Counting Imaging Sensor

    Science.gov (United States)

    Zheng, Xinyu; Cunningham, Thomas J.; Sun, Chao; Wang, Kang L.

    2011-01-01

    The single-photon counting imaging sensor is typically an array of silicon Geiger-mode avalanche photodiodes that are monolithically integrated with CMOS (complementary metal oxide semiconductor) readout, signal processing, and addressing circuits located in each pixel and the peripheral area of the chip. The major problem is its single-event method for photon count number registration. A single-event single-photon counting imaging array only allows registration of up to one photon count in each of its pixels during a frame time, i.e., the interval between two successive pixel reset operations. Since the frame time can t be too short, this will lead to very low dynamic range and make the sensor merely useful for very low flux environments. The second problem of the prior technique is a limited fill factor resulting from consumption of chip area by the monolithically integrated CMOS readout in pixels. The resulting low photon collection efficiency will substantially ruin any benefit gained from the very sensitive single-photon counting detection. The single-photon counting imaging sensor developed in this work has a novel multiple-event architecture, which allows each of its pixels to register as more than one million (or more) photon-counting events during a frame time. Because of a consequently boosted dynamic range, the imaging array of the invention is capable of performing single-photon counting under ultra-low light through high-flux environments. On the other hand, since the multiple-event architecture is implemented in a hybrid structure, back-illumination and close-to-unity fill factor can be realized, and maximized quantum efficiency can also be achieved in the detector array.

  1. Technology development for a single-photon source

    International Nuclear Information System (INIS)

    m to 1.5 μm was obtained. To achieve high collection efficiency, the quantum dots should be embedded into photonic crystals. An ArCl2-etch-process was developed which enables the etch of small features in AlxGayIn1-x-yAs material system to transfer the Si3N4-pattern into the semiconductor. Using this process the fabricated photonic crystals with L3-cavities had Q-factors around 2200. Any concept using a cavity needs a mechanism to control the frequency-detuning between the mode and the quantum dots, due to the inhomogeneous frequency broadening of the quantum dots. Thus an in-situ tuning mechanism is required for adjusting the emission wavelength of the quantum dot or cavity mode, respectively. This concept intents to use the quantum confined Stark effect (QCSE) to force the emission of a single photon out of a quantum dot into the photonic crystal mode. This is realized using a reversed biased Schottky contact to cause a red-shift of the emission of a single quantum dot. Electroluminescence measurements on the device show, that even with very low currents of 14.5 μA the saturation intensity of single quantum dots could be reached. (orig.)

  2. EXPLORING THE REGIONAL CEREBRAL BLOOD FLOW IN A PATIENT WITH ANOREXIA NERVOSA USING 99mTc-ECD SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY%神经性厌食99mTc-ECD局部脑血流变化初探

    Institute of Scientific and Technical Information of China (English)

    金珏; 马莹华; 唐一源; 冯洪波; 于庆宝; 张晔; 杜雪梅; 张延军

    2007-01-01

    神经性厌食(Anorexia Nervosa,AN)是一种病因未明的心理行为综合症,社会文化及生物学因素间的交互作用被认为是该病的病因,脑成像体现出一些病理相关改变,但国内尚未见针对此病的成像报道.为给临床辅助诊断AN提供依据,采用经济、易获得的脑功能显像技术--单光子发射计算机断层显像(Single Photon Emission Computed Tomography,SPECT),扫描3位典型青年女性AN患者的大脑.通过统计参数图(Statistical Parametric Mapping,SPM2),基于体素的局部脑血流灌注分析,与25名正常青年女性脑图相比较发现,患者的前扣带和前额内侧、双侧额叶背外侧、后顶叶、颞叶中上部和小脑血流灌注降低,下丘脑、双侧颞叶中下部血流灌注增高,可能与神经递质回路有关,提示社会学因素可能只是该病的诱因,而生物学人格易感性才是该病的主要原因,同时说明SPECT脑血流成像有助于AN的临床辅助诊断.

  3. 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.

  4. Quantum key distribution over 120 km using ultrahigh purity single-photon source and superconducting single-photon detectors

    Science.gov (United States)

    Takemoto, Kazuya; Nambu, Yoshihiro; Miyazawa, Toshiyuki; Sakuma, Yoshiki; Yamamoto, Tsuyoshi; Yorozu, Shinichi; Arakawa, Yasuhiko

    2015-09-01

    Advances in single-photon sources (SPSs) and single-photon detectors (SPDs) promise unique applications in the field of quantum information technology. In this paper, we report long-distance quantum key distribution (QKD) by using state-of-the-art devices: a quantum-dot SPS (QD SPS) emitting a photon in the telecom band of 1.5 μm and a superconducting nanowire SPD (SNSPD). At the distance of 100 km, we obtained the maximal secure key rate of 27.6 bps without using decoy states, which is at least threefold larger than the rate obtained in the previously reported 50-km-long QKD experiment. We also succeeded in transmitting secure keys at the rate of 0.307 bps over 120 km. This is the longest QKD distance yet reported by using known true SPSs. The ultralow multiphoton emissions of our SPS and ultralow dark count of the SNSPD contributed to this result. The experimental results demonstrate the potential applicability of QD SPSs to practical telecom QKD networks.

  5. Time-reversal-symmetric single-photon wave packets for free-space quantum communication.

    Science.gov (United States)

    Trautmann, N; Alber, G; Agarwal, G S; Leuchs, G

    2015-05-01

    Readout and retrieval processes are proposed for efficient, high-fidelity quantum state transfer between a matter qubit, encoded in the level structure of a single atom or ion, and a photonic qubit, encoded in a time-reversal-symmetric single-photon wave packet. They are based on controlling spontaneous photon emission and absorption of a matter qubit on demand in free space by stimulated Raman adiabatic passage. As these processes do not involve mode selection by high-finesse cavities or photon transport through optical fibers, they offer interesting perspectives as basic building blocks for free-space quantum-communication protocols.

  6. Interfering Heralded Single Photons from Two Separate Silicon Nanowires Pumped at Different Wavelengths

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2016-08-01

    Full Text Available Practical quantum photonic applications require on-demand single photon sources. As one possible solution, active temporal and wavelength multiplexing has been proposed to build an on-demand single photon source. In this scheme, heralded single photons are generated from different pump wavelengths in many temporal modes. However, the indistinguishability of these heralded single photons has not yet been experimentally confirmed. In this work, we achieve 88% ± 8% Hong–Ou–Mandel quantum interference visibility from heralded single photons generated from two separate silicon nanowires pumped at different wavelengths. This demonstrates that active temporal and wavelength multiplexing could generate indistinguishable heralded single photons.

  7. Widely Tunable Single-Photon Source from a Carbon Nanotube in the Purcell Regime

    Science.gov (United States)

    Jeantet, A.; Chassagneux, Y.; Raynaud, C.; Roussignol, Ph.; Lauret, J. S.; Besga, B.; Estève, J.; Reichel, J.; Voisin, C.

    2016-06-01

    The narrow emission of a single carbon nanotube at low temperature is coupled to the optical mode of a fiber microcavity using the built-in spatial and spectral matching brought by this flexible geometry. A thorough cw and time-resolved investigation of the very same emitter both in free space and in cavity shows an efficient funneling of the emission into the cavity mode together with a strong emission enhancement corresponding to a Purcell factor of up to 5. At the same time, the emitted photons retain a strong sub-Poissonian statistics. By exploiting the cavity feeding effect on the phonon wings, we locked the emission of the nanotube at the cavity resonance frequency, which allowed us to tune the frequency over a 4 THz band while keeping an almost perfect antibunching. By choosing the nanotube diameter appropriately, this study paves the way to the development of carbon-based tunable single-photon sources in the telecom bands.

  8. Video recording true single-photon double-slit interference

    CERN Document Server

    Aspden, Reuben S; Spalding, Gabriel C

    2016-01-01

    As normally used, no commercially available camera has a low-enough dark noise to directly produce video recordings of double-slit interference at the photon-by-photon level, because readout noise significantly contaminates or overwhelms the signal. In this work, noise levels are significantly reduced by turning on the camera only when the presence of a photon has been heralded by the arrival, at an independent detector, of a time-correlated photon produced via parametric down-conversion. This triggering scheme provides the improvement required for direct video imaging of Young's double-slit experiment with single photons, allowing clarified versions of this foundational demonstration. Further, we introduce variations on this experiment aimed at promoting discussion of the role spatial coherence plays in such a measurement. We also emphasize complementary aspects of single-photon measurement, where imaging yields (transverse) position information, while diffraction yields the transverse momentum, and highligh...

  9. Authenticated Quantum Key Distribution with Collective Detection using Single Photons

    Science.gov (United States)

    Huang, Wei; Xu, Bing-Jie; Duan, Ji-Tong; Liu, Bin; Su, Qi; He, Yuan-Hang; Jia, Heng-Yue

    2016-05-01

    We present two authenticated quantum key distribution (AQKD) protocols by utilizing the idea of collective (eavesdropping) detection. One is a two-party AQKD protocol, the other is a multiparty AQKD protocol with star network topology. In these protocols, the classical channels need not be assumed to be authenticated and the single photons are used as the quantum information carriers. To achieve mutual identity authentication and establish a random key in each of the proposed protocols, only one participant should be capable of preparing and measuring single photons, and the main quantum ability that the rest of the participants should have is just performing certain unitary operations. Security analysis shows that these protocols are free from various kinds of attacks, especially the impersonation attack and the man-in-the-middle (MITM) attack.

  10. Quantum private query based on single-photon interference

    Science.gov (United States)

    Xu, Sheng-Wei; Sun, Ying; Lin, Song

    2016-08-01

    Quantum private query (QPQ) has become a research hotspot recently. Specially, the quantum key distribution (QKD)-based QPQ attracts lots of attention because of its practicality. Various such kind of QPQ protocols have been proposed based on different technologies of quantum communications. Single-photon interference is one of such technologies, on which the famous QKD protocol GV95 is just based. In this paper, we propose two QPQ protocols based on single-photon interference. The first one is simpler and easier to realize, and the second one is loss tolerant and flexible, and more practical than the first one. Furthermore, we analyze both the user privacy and the database privacy in the proposed protocols.

  11. Authenticated Quantum Key Distribution with Collective Detection using Single Photons

    Science.gov (United States)

    Huang, Wei; Xu, Bing-Jie; Duan, Ji-Tong; Liu, Bin; Su, Qi; He, Yuan-Hang; Jia, Heng-Yue

    2016-10-01

    We present two authenticated quantum key distribution (AQKD) protocols by utilizing the idea of collective (eavesdropping) detection. One is a two-party AQKD protocol, the other is a multiparty AQKD protocol with star network topology. In these protocols, the classical channels need not be assumed to be authenticated and the single photons are used as the quantum information carriers. To achieve mutual identity authentication and establish a random key in each of the proposed protocols, only one participant should be capable of preparing and measuring single photons, and the main quantum ability that the rest of the participants should have is just performing certain unitary operations. Security analysis shows that these protocols are free from various kinds of attacks, especially the impersonation attack and the man-in-the-middle (MITM) attack.

  12. Quantum computing with distant single photon sources with insurance

    CERN Document Server

    Lim, Y L; Kwek, L C; Lim, Yuan Liang; Beige, Almut; Kwek, Leong Chuan

    2004-01-01

    We demonstrate the possibility to perform quantum computations using only single photon sources, linear optics elements and photon detectors. In contrast to common linear optics quantum computing proposals, the described scheme can be operated with insurance without relying on highly entangled ancilla photons. Universality is achieved by employing the properties of certain single photon sources, namely the fact that it is possible to encode the logical qubit within the state of a source as well as in the state of the generated photon. The proposed Ising gate allows to build cluster states for one-way quantum computing. Furthermore we describe the implementation of the quantum parity filter, enabling teleportation with insurance, and the generation of multiphoton entanglement on demand.

  13. Hyperbolic Metamaterial Nano-Resonators Make Poor Single Photon Sources

    CERN Document Server

    Axelrod, Simon; Wong, Herman M K; Helmy, Amr S; Hughes, Stephen

    2016-01-01

    We study the optical properties of quantum dipole emitters coupled to hyperbolic metamaterial nano-resonators using a semi-analytical quasinormal mode approach. We show that coupling to metamaterial nano-resonators can lead to significant Purcell enhancements that are nearly an order of magnitude larger than those of plasmonic resonators with comparable geometry. However, the associated single photon output $\\beta$-factors are extremely low (around 10%), far smaller than those of comparable sized metallic resonators (70%). Using a quasinormal mode expansion of the photon Green function, we describe how the low $\\beta$-factors are due to increased Ohmic quenching arising from redshifted resonances, larger quality factors and stronger confinement of light within the metal. In contrast to current wisdom, these results suggest that hyperbolic metamaterial nano-structures make poor choices for single photon sources.

  14. Nanoantenna enhancement for telecom-wavelength superconducting single photon detectors

    CERN Document Server

    Heath, Robert M; Drysdale, Timothy D; Miki, Shigehito; Giannini, Vincenzo; Maier, Stefan A; Hadfield, Robert H

    2015-01-01

    Superconducting nanowire single photon detectors are rapidly emerging as a key infrared photon-counting technology. Two front-side-coupled silver dipole nanoantennas, simulated to have resonances at 1480 nm and 1525 nm, were fabricated in a two-step process. An enhancement of 50% to 130% in the system detection efficiency was observed when illuminating the antennas. This offers a pathway to increasing absorption into superconducting nanowires, creating larger active areas, and achieving more efficient detection at longer wavelengths.

  15. Telecom-wavelength single-photon sources for quantum communications

    International Nuclear Information System (INIS)

    This paper describes the progress towards the realization of efficient single-photon sources based on semiconductor quantum dots (QDs), for application in quantum key distribution and, more generally, quantum communications. We describe the epitaxial growth of QD arrays with low areal density and emitting in the telecom wavelength range, the nanofabrication of single-QD structures and devices, and their optical and electro-optical characterization. The potential for integration with monolithic microcavities is also discussed

  16. Superconducting nanowire single photon detectors for quantum information and communications

    OpenAIRE

    Wang, Zhen; Miki, Shigehito; Fujiwara, Mikio

    2010-01-01

    Superconducting nanowire single photon detectors (SNSPD or SSPD) are highly promising devices in the growing field of quantum information and communications technology. We have developed a practical SSPD system with our superconducting thin films and devices fabrication, optical coupling packaging, and cryogenic technology. The SSPD system consists of six-channel SSPD devices and a compact Gifford-McMahon (GM) cryocooler, and can operate continuously on 100 V ac power without the need for any...

  17. Engineering single photon emitters by ion implantation in diamond

    OpenAIRE

    Naydenov, B.; Kolesov, R.; Batalov, A.; Meijer, J; Pezzagna, S.; Rogalla, D.; Jelezko, F.; Wrachtrup, J.

    2009-01-01

    Diamond provides unique technological platform for quantum technologies including quantum computing and communication. Controlled fabrication of optically active defects is a key element for such quantum toolkit. Here we report the production of single color centers emitting in the blue spectral region by high energy implantation of carbon ions. We demonstrate that single implanted defects show sub-poissonian statistics of the emitted photons and can be explored as single photon source in qua...

  18. Single photon detection with self-quenching multiplication

    Science.gov (United States)

    Zheng, Xinyu (Inventor); Cunningham, Thomas J. (Inventor); Pain, Bedabrata (Inventor)

    2011-01-01

    A photoelectronic device and an avalanche self-quenching process for a photoelectronic device are described. The photoelectronic device comprises a nanoscale semiconductor multiplication region and a nanoscale doped semiconductor quenching structure including a depletion region and an undepletion region. The photoelectronic device can act as a single photon detector or a single carrier multiplier. The avalanche self-quenching process allows electrical field reduction in the multiplication region by movement of the multiplication carriers, thus quenching the avalanche.

  19. Advanced active quenching circuits for single-photon avalanche photodiodes

    Science.gov (United States)

    Stipčević, M.; Christensen, B. G.; Kwiat, P. G.; Gauthier, D. J.

    2016-05-01

    Commercial photon-counting modules, often based on actively quenched solid-state avalanche photodiode sensors, are used in wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single photon arrival time resolution (jitter), however they usually do not specify the conditions under which these parameters are constant or present a sufficient description. In this work, we present an in-depth analysis of the active quenching process and identify intrinsic limitations and engineering challenges. Based on that, we investigate the range of validity of the typical parameters used by two commercial detectors. We identify an additional set of imperfections that must be specified in order to sufficiently characterize the behavior of single-photon counting detectors in realistic applications. The additional imperfections include rate-dependence of the dead time, jitter, detection delay shift, and "twilighting." Also, the temporal distribution of afterpulsing and various artifacts of the electronics are important. We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the system's performance. Specifically, we discuss implications of these new findings in a few applications in which single-photon detectors play a major role: the security of a quantum cryptographic protocol, the quality of single-photon-based random number generators and a few other applications. Finally, we describe an example of an optimized avalanche quenching circuit for a high-rate quantum key distribution system based on time-bin entangled photons.

  20. Single-photon ultrashort-lived radionuclides: symposium proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Paras, P.; Thiessen, J.W. (eds.)

    1985-01-01

    The purpose was to define the current role and state-of-the-art regarding the development, clinical applications, and usefulness of generator-produced single-photon ultrashort-lived radionuclides (SPUSLR's) and to predict their future impact on medicine. Special emphasis was placed on the generator production of iridium-191, gold-195, and krypton-81. This report contains expanded summaries of the included papers. (ACR)