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Sample records for 99mtc-mibi single-photon emission

  1. Single photon emission computerized tomography

    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.)

  2. Single-photon emission tomography.

    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

  3. Single Photon Emission Computed Tomography (SPECT)

    ... 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 ...

  4. Experimental study on 13N-NH3 and 99MTc-MIBI myocardial perfusion imaging in rabbits with subacute myocardial infarction of ischemic reperfusion

    Purpose: To explore the relationship between 13N-NH3 and 99mTc-MIBI myocardial perfusion imaging in rabbits with subacute myocardial infarction of ischemic reperfusion. Methods: Eight male New Zealand White rabbits of which left anterior descending (LAD) coronary arteries were completely occluded for 45 min followed by 7-10 d reperfusion. One week later, the rabbits after an overnight fast were anaesthetized with sodium pentobarbital (30 mg/kg), and LAD arteries were religated for 45 min followed by 2 h reperfusion. Then the animals were positioned on the LS-PET/CT (4 row spirals CT, Discovery GE. US) table. Myocardial blood flows were obtained with 148 MBq 13N-NH3 administered via a marginal ear vein over 20 s. According to PET imaging procedure, PET/CT acquisition of dynamic scans began 5 min after injection and was accomplished within 10 min. Two hours after PET imaging the rabbits were injected with 148 MBq 99mTc-MIBI via a marginal ear vein, 30 min later myocardial perfusion imaging was performed under a single-photon emission computed tomography (SPECT). PET imaging ZOOM value was generally amplified 6 times while that of SPECT was 3 times. Tomographic images along the vertical long, horizontal long and short axes were created. Tomographic reconstruction was then performed by dividing the PET and SPECT image of the LV on a polar map into 9 segments for semi- quantitative analysis. The changes of infarct size were determined by triphenyl tetrazolium chloride (TTC) staining. The ultra-structural damage of myocardial cells in infarct and periphery areas were observed under transmission electron microscope. Results: Infarct size (24.2±1.9)% of LV mass by TTC staining, while (23.7±2.3)% vs. (20.5± 2.5)% (P < 0.001) by 99mTc-MIBI Hawkeye-SPECT and 13N-NH3 PET/CT respectively. Serious myocardial cell damages including myocardial cell denaturalization, texture, and karyolysis in infracted area and myocardial cells swelling in the periphery of infracted area was

  5. Single photon emission computed tomography (SPECT)

    The functional state of organs can be imaged by their accumulation of single photon emitter like 99mTc (γ-ray energy 140 keV), 201Tl (73 keV) and 201I (159 keV) with computed tomography. The emitted γ-ray is collimated to reach the NaI (Tl) detector for specifying its direction, which is called as the scintillation camera or gamma camera. The camera rotating around the patient gives the SPECT images. The NaI (Tl) detector is suitable for converting 60-300 keV γ-ray to fluorescence through the photoelectric effect. Photomultiplier receiving the fluorescence outputs X/Y signals for the emitting position and Z signal (energy) separately, giving imaging data. 3D images can be re-constructed by either method of the filtered back projection or maximum likelihood-expectation maximization. For quantitative reconstruction, correction of γ-ray absorption in water, of scattering and of collimator opening is necessary. Recently, semiconductor-detectors like CdZnTe and CdTe are being utilized in place of NaI for better resolution, which will reduce the size of the camera. Further, a camera with coincidence circuit for positron has appeared and will be applicable for both SPECT and PET. Compton camera having 2-step detectors without collimator is now under development. (N.I.)

  6. Single photon emission computed tomography (SPECT): Fundamentals, technique, clinical applications

    The fundamentals of SPECT (Single Photon Emission Computed Tomography) are presented, and the requirements on rotating SPECT systems are listed. SPECT with a rotating gamma camera has found general acceptance as an imaging method in nuclear medicine. Compared with conventional, two-dimensional imaging techniques, SPECT offers higher contrast and three-dimensional transversal, sagittal, coronal or oblique sectional images. (orig./MG)

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

    Acton, Paul D.; P. David Mozley

    2000-01-01

    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 metabolis...

  8. Directional emission of single photons from small atomic samples

    Miroshnychenko, Yevhen; V. Poulsen, Uffe; Mølmer, Klaus

    2013-01-01

    We provide a formalism to describe deterministic emission of single photons with tailored spatial and temporal profiles from a regular array of multi-level atoms. We assume that a single collective excitation is initially shared by all the atoms in a metastable atomic state, and that this state i...... coupled by a classical laser field to an optically excited state which rapidly decays to the ground atomic state. Our model accounts for the different field polarization components via re-absorption and emission of light by the Zeeman manifold of optically excited states.......We provide a formalism to describe deterministic emission of single photons with tailored spatial and temporal profiles from a regular array of multi-level atoms. We assume that a single collective excitation is initially shared by all the atoms in a metastable atomic state, and that this state is...

  9. Clinical results of quantitative single photon emission tomography

    In addition to the traditional skills of pattern recognition in the interpretation of images, it is necessary to add quantitative techniques, particularly in difficult problems, to determine normal and abnormal variation. Single photon emission tomography, SPET, overcomes the problems of tissue background and superficial tissue overlying a suspect lesion. Nevertheless, the goal of absolute quantitation is important in the solution to several clinical problems. The use and success of quantitative SPET in the liver, heart, adrenal and pituitary glands are reviewed. (author)

  10. Single-Photon Emission Computed Tomography in Neurotherapeutics

    Devous, Michael D.

    2005-01-01

    Summary: The measurement of regional cerebral blood flow (rCBF) by single-photon emission computed tomography (SPECT) is a powerful clinical and research tool. There are several clinical applications now documented, a substantial number under active investigation, and a larger number yet to be studied. Standards regarding patient imaging environment and image presentation are becoming established. This article reviews key aspects of SPECT functional brain imaging in clinical practice, with a ...

  11. Enhanced Single Photon Emission from a Diamond-Silver Aperture

    Choy, Jennifer T; Babinec, Thomas M; Bulu, Irfan; Khan, Mughees; Maletinsky, Patrick; Yacoby, Amir; Lončar, Marko

    2011-01-01

    We have developed a scalable method for coupling single color centers in diamond to plasmonic resonators and demonstrated Purcell enhancement of the single photon emission rate of nitrogen-vacancy (NV) centers. Our structures consist of single nitrogen-vacancy (NV) center-containing diamond nanoposts embedded in a thin silver film. We have utilized the strong plasmon resonances in the diamond-silver apertures to enhance the spontaneous emission of the enclosed dipole. The devices were realized by a combination of ion implantation and top-down nanofabrication techniques, which have enabled deterministic coupling between single NV centers and the plasmonic modes for multiple devices in parallel. The plasmon-enhanced NV centers exhibited over six-fold improvements in spontaneous emission rate in comparison to bare nanoposts and up to a factor of 3.6 in radiative lifetime reduction over bulk samples, with comparable increases in photon counts. The hybrid diamond-plasmon system presented here could provide a stabl...

  12. SPECT single photon emission computed tomography: A primer

    This book aims to assist nuclear medicine technologists in expanding their knowledge of nuclear medicine to include SPECT. The text of this primer is written with the assumption that the reader is proficient in most elements of nuclear medicine technology; therefore, the information is limited to data that will answer the basic questions of single-photon emission computed tomography .... The authors' goal is to bring the basics of this material together in a manner that would answer the technologist's fundamental questions. The authors have designed this primer in a generic manner to be used as an extension of the manufacturer's operating manual .... A glossary is included which contains some of the terminology relevant to the specialty, and reading lists are provided at the end of each chapter to direct the reader to more comprehensive text on specific subjects

  13. Signs of cerebral atrophy on single-photon emission tomography.

    Wong, C O; Meyerrose, G E; Sostre, S

    1994-05-01

    Cerebral atrophy often coexists with other brain disorders and by itself may alter the pattern of cerebral perfusion. If unrecognized, it may confound diagnoses based on brain single-photon emission tomography (SPET). In this retrospective study, we describe and evaluate criteria for the diagnosis of cerebral atrophy on technetium-99m hexamethylpropylene amine oxime brain SPET studies. The SPET scans of 11 patients with cerebral atrophy and ten controls were evaluated for the presence of a prominent interhemispheric fissure, presence of prominent cerebral sulci, separation of thalamic nuclei, and pronounced separation of caudate nuclei. The SPET studies were interpreted by two independent observers blind to the findings of magnetic resonance imaging, which provided the final diagnosis of cerebral atrophy. The combination of the four scintigraphic signs was accurate in the diagnosis of cerebral atrophy in 95% of the cases and had a sensitivity of 91% and a specificity of 100%. PMID:8062851

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

    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...

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

    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.

  16. Single photon emission tomography imaging in parkinsonian disorders: a review.

    Acton, P D; Mozley, P D

    2000-01-01

    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. PMID:11455039

  17. Single photon emission computed tomography in periatric frontal epilepsy

    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.)

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

    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)

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

    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.

  20. Brain single photon emission computed tomography in neonates

    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

  1. Brain single photon emission computed tomography in neonates

    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.

  2. Single photon emission computed tomography: A clinical experience

    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

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

    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

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

    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)

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

    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

  6. Photophysics of single silicon vacancy centers in diamond: implications for single photon emission

    Neu, Elke; Becher, Christoph

    2012-01-01

    Single silicon vacancy (SiV) color centers in diamond have recently shown the ability for high brightness, narrow bandwidth, room temperature single photon emission. This work develops a model describing the three level population dynamics of single SiV centers in diamond nanocrystals on iridium surfaces including an intensity dependent de-shelving process. Furthermore, we investigate the brightness and photostability of single centers and find maximum single photon rates of 6.2 Mcps under continuous excitation. We investigate the collection efficiency of the fluorescence and estimate quantum efficiencies of the SiV centers.

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

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

    2012-01-01

    The photonic nanowire has recently emerged as an promising alternative to microcavity-based single-photon source designs. In this simple structure, a geometrical effect ensures a strong coupling between an embedded emitter and the optical mode of interest and a combination of tapers and mirrors 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...

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

    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...

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

    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...

  10. First experiences from Copenhagen with paediatric single photon emission computed tomography/computed tomography

    Mortensen, Jann; Bech, Birthe Højlund; Højgaard, Liselotte;

    2011-01-01

    OBJECTIVE: This study evaluates the diagnostic value of single photon emission computed tomographic (SPECT)/multislice computed tomographic (MSCT) fusion images compared with planar scintigraphy in children. METHODS: Fifteen children [eight girls, mean age 13 years (range 2-17 years)] who were...

  11. A number of clinical applications of single photon emission tomography

    Since a number of years, emission computed tomography has enabled the reconstruction of three dimensional images of structures and processes in the body from projection images, obtained from patients with the aid of X-rays or gamma radiation. A number of these reconstructed images are presented which illustrate the clinical applications of this technique. The principles, procedure and instrumentation are also outlined. (C.F.)

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

    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...

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

    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

  14. Single-photon emission in the near infrared from diamond colour centre

    Optically active colour centres based on nickel-nitrogen impurities are observed in natural diamond under continuous-wave excitation. The spectral analysis shows that the single emitters have a narrow band emission in the near infrared, around 780 nm, which is almost entirely concentrated in the zero phonon line even at room temperature. The colour centre excited-state lifetime is as short as 2 ns, and the photoluminescence light is linear polarized. These striking features pave the way to the realization of a triggered single-photon source based on this colour centre emission well suited for open-air single-photon Quantum Key Distribution operating in day-light conditions

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

    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

  16. 201Tl single photon emission tomography in the evaluation of residual and recurrent astrocytoma

    Twenty-five patients with malignant astrocytoma, either postoperatively (15 cases) or with recurrent tumour versus gliosis (10 cases) were included in this study. 201T1 single photon emission computed tomography (SPECT) was performed with the calculation of early and delayed uptake values and retention index. There was a higher sensitivity in detection of tumour viability by 201T1 SPECT of 100% versus 80% using computed tomographic scanning and in the differentiation between recurrent tumour and postradiation gliosis. (author)

  17. [sup 201]Tl single photon emission tomography in the evaluation of residual and recurrent astrocytoma

    Moustafa, H.M.; Ziada, G.A.; El-Ghonimy, E.G. (Cairo Univ., El Mansura (Egypt). Faculty of Medicine); Omar, W.M.; Ezzat, I. (Cairo Univ. (Egypt). Cancer Inst.)

    1994-03-01

    Twenty-five patients with malignant astrocytoma, either postoperatively (15 cases) or with recurrent tumour versus gliosis (10 cases) were included in this study. [sup 201]T1 single photon emission computed tomography (SPECT) was performed with the calculation of early and delayed uptake values and retention index. There was a higher sensitivity in detection of tumour viability by [sup 201]T1 SPECT of 100% versus 80% using computed tomographic scanning and in the differentiation between recurrent tumour and postradiation gliosis. (author).

  18. Image Reconstruction from Truncated Data in Single-Photon Emission Computed Tomomgraphy with Uniform Attenuation

    Noo, Frederic; Defrise, Michel; Pack, Jed; Clackdoyle, Rolf

    2007-01-01

    We present a mathematical analysis of the problem of image reconstruction from truncated data in two-dimensional (2D) single-photon emission computed tomography (SPECT). Recent results in classical tomography have shown that accurate reconstruction of some parts of the object is possible in the presence of truncation. We have investigated how these results extend to 2D parallel-beam SPECT, assuming that the attenuation map is known and constant in a convex region $\\Omega$ that includes all ac...

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

    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...

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

    Michael T Hirschmann

    2011-01-01

    Full Text Available 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 are frequently seen in most shoulder clinics.

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

    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 99mTc point source and a Jaszczak Phantom with the both experiment and si...

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

    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.)

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

    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.

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

    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.

  5. Brain receptor single-photon emission computer tomography with 123I Datscan in Parkinson's disease

    Clinical aspects of Parkinson's disease are not enough for the early diagnosis of the disease. Positron emission tomography and the receptor single - photon emission tomography can be used for imaging functional integrity of nigrostriatal dopaminergic structures. 24 patient (17 men and 7 women) were investigated. 20 of them are with Parkinson's disease and 4 are with essential tremor. The radiopharmaceutical - 123I-Datscan (ioflupane, bind with 123I) represent a cocaine analogue with selective affinity to dopamine transporters, located in the dopaminergic nigrostriatal terminals in the striatum. Single - photon emission computer tomography was performed with SPECT gamma camera (ADAC, SH Epic detector). The scintigraphic study was made 3 to 6 hours after intravenous injection of the radiopharmaceutical - 123I- Datscan in dose 185 MBq. 120 frames are registered with duration of each one 22 seconds and gamma camera rotation 360. After generation of transversal slices we generated two composites pictures. The first composite picture image the striatum, the second - the occipital region. Two ratios were calculated representing the uptake of the radiopharmaceutical in the left and right striatum. Qualitative and quantitative criteria were elaborated for evaluating the scintigraphic patterns. Decreased, nonhomogeneous and asymmetric uptake of the radiopharmaceutical coupled with low quantitative parameters in range from 1.44 to 2.87 represents the characteristic scintigraphic pattern for Parkinson's disease with clear clinical picture. Homogenous with high intensity and symmetric uptake of the radiopharmaceutical in the striatum coupled with his clear frontier and with quantitative parameters up to 4.40 represent the scintigraphic pattern in two patients with essential tremor. Receptor single - photon emission computer tomography with 123I - Datscan represents an accurate nuclear-medicine method for precise diagnosis of Parkinson's disease and for its differentiation from

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

    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.

  7. Corticobasal degeneration: structural and functional MRI and single-photon emission computed tomography

    We studied seven patients with corticobasal degeneration (CBD) from a clinical and imaging perspective. We describe the main morphological features of CBD and, using functional MRI, try to define the possible role of the parietal lobe in simple and complex learned motor sequences. We showed decreased activation of the parietal lobe contralateral to the more affected arm, when movements, simple or complex, are performed with that hand. Moreover we found that functional imaging can demonstrate parietal and motor cortex dysfunction before structural, and even single-photon emission computed tomography changes become evident. (orig.)

  8. Corticobasal degeneration: structural and functional MRI and single-photon emission computed tomography

    Ukmar, M. [Department of Radiology, University of Trieste (Italy); Moretti, R.; Bava, A. [Department of Physiology and Pathology, University of Trieste (Italy); Torre, P.; Antonello, R.M. [Department of Internal Medicine and Clinical Neurology, University of Trieste (Italy); Longo, R. [Department of Physics, University of Trieste (Italy)

    2003-10-01

    We studied seven patients with corticobasal degeneration (CBD) from a clinical and imaging perspective. We describe the main morphological features of CBD and, using functional MRI, try to define the possible role of the parietal lobe in simple and complex learned motor sequences. We showed decreased activation of the parietal lobe contralateral to the more affected arm, when movements, simple or complex, are performed with that hand. Moreover we found that functional imaging can demonstrate parietal and motor cortex dysfunction before structural, and even single-photon emission computed tomography changes become evident. (orig.)

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

    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.

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

    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.

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

    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)

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

    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

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

    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.

  14. Synthesis and evaluation of novel serotonin 4 receptor radiotracers for single photon emission computed tomography.

    Lalut, Julien; Tournier, Benjamin B; Cailly, Thomas; Lecoutey, Cédric; Corvaisier, Sophie; Davis, Audrey; Ballandonne, Céline; Since, Marc; Millet, Philippe; Fabis, Frédéric; Dallemagne, Patrick; Rochais, Christophe

    2016-06-30

    Despite its implication in several physiological and pathological processes the serotonin subtype-4 receptor (5-HT4R) has seen limited effort for the development of radiolabeling agent especially concerning single photon emission computed tomography (SPECT). Bearing an ester function, the available ligands are rapidly susceptible to hydrolysis which limits their use in vivo. In this study the synthesis of iodinated benzamide and ketone analogs were described. Their affinity for the 5-HT4R and their lipophilicity were evaluated and the most promising derivatives were evaluated ex vivo for their binding to the receptor and for their ability to displace the reference ligand [(125)I]-SB207710. PMID:27060761

  15. Single photon emission computed tomography scanning in the diagnosis of knee pathology.

    Vellala RP

    2004-06-01

    Full Text Available PURPOSE. To evaluate the role of single photon emission computed tomography (SPECT bone scan for the diagnosis of knee lesions in routine clinical practice. METHODS. 40 consecutive case records were examined in patients who underwent a SPECT scan prior to knee arthroscopy in routine clinical practice. The accuracy of clinical examination, SPECT scan results, and arthroscopic findings (as the gold standard in diagnosing knee lesions were compared. RESULTS. The sensitivity of SPECT scans in detecting medial meniscal, lateral meniscal, anterior cruciate ligament lesions, osteochondral defects, and chondromalacia patellae was 77%, 14%, 33%, 50%, and 74%, respectively. The specificities for the same structural lesions were high at 89%, 94%, 97%, 94%, and 69%, respectively. CONCLUSION. SPECT bone scan appears to be useful in the diagnosis of knee pathology in routine practice and in selecting patients for arthroscopy, especially most useful for the diagnosis of medial meniscal tears.

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

    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)

  17. Krypton-81m single photon emission tomography and the collateral circulation in carotid occlusion

    Cerebral perfusion images were investigated in patients with carotid artery occlusion, using single photon emission computed tomography with the infusion of krypton-81m into the internal, common carotid and vertebral arteries. The contribution of the circle of Willis and cerebral cortical anastomoses to the maintenance of adequate blood supply into the involved hemisphere was analysed. It was concluded that the cerebral perfusion image is superior to angiography in evaluating collateral circulation, and in the case of carotid occlusion, the circle of Willis is important in preventing infarction in the territory of the perforating arteries, while the cerebral cortex mainly receives its blood supply through the cortical leptomeningeal anastomoses, illustrating the major role of the leptomeningeal anastomosis as a collateral channel. (orig.)

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

    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.)

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

    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.

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

    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)

  1. Depression following intracerebral hemorrhage and the evaluation of cerebral blood flow by single photon emission tomography

    The authors studied patients who presented depression and apathy following intracerebral hemorrhage (ICH). Twelve patients who were admitted in our hospital were divided into two groups according to the presence of post-stroke depression (PSD). Five patients with PSD are in group A, and another seven patients without PSD are in group B. Zung-self depression scale (SDS) and apathy scale were used for screening of depression and apathy. PSD was recognized in 5 (42%) of patients following ICH. Single photon emission tomography (SPECT) suggested the reduction of cerebral blood flow (CBF) in the frontal lobe in all patients of the group A (100%), whereas only 29% of patients of the group B. The reduction of CBF in the frontal lobe might be involved in the mechanism of depression following ICH in subacute stage. (author)

  2. Brain perfusion single photon emission computed tomography in major psychiatric disorders: From basics to clinical practice

    Brain single photon emission computed tomography (SPECT) is a well-established and reliable method to assess brain function through measurement of regional cerebral blood flow (rCBF). It can be used to define a patient's pathophysiological status when neurological or psychiatric symptoms cannot be explained by anatomical neuroimaging findings. Though there is ample evidence validating brain SPECT as a technique to track human behavior and correlating psychiatric disorders with dysfunction of specific brain regions, only few psychiatrists have adopted brain SPECT in routine clinical practice. It can be utilized to evaluate the involvement of brain regions in a particular patient, to individualize treatment on basis of SPECT findings, to monitor the treatment response and modify treatment, if necessary. In this article, we have reviewed the available studies in this regard from existing literature and tried to present the evidence for establishing the clinical role of brain SPECT in major psychiatric illnesses

  3. Myocardial stunning in hypertrophic cardiomyopathy: recovery predicted by single photon emission computed tomographic thallium-201 scintigraphy

    A young woman with hypertrophic cardiomyopathy confirmed by echocardiography and cardiac catheterization presented with chest pain and features of a large left ventricular aneurysm. The initial diagnosis was myocardial ischemia with either an evolving or an ancient myocardial infarction. Subsequently, verapamil therapy was associated with complete resolution of the extensive left ventricular wall motion abnormalities, normalization of left ventricular ejection fraction and a minimal myocardial infarction. Normal thallium uptake on single photon emission computed tomographic scintigraphy early in the hospital course predicted myocardial viability in the region of the aneurysm. Thus, orally administered verapamil may reverse spontaneous extensive myocardial ischemia in hypertrophic cardiomyopathy and possibly limit the extent of myocardial infarction in such circumstances

  4. An artificial neural net and error backpropagation to reconstruct single photon emission computerized tomography data.

    Knoll, P; Mirzaei, S; Müllner, A; Leitha, T; Koriska, K; Köhn, H; Neumann, M

    1999-02-01

    At present, algorithms used in nuclear medicine to reconstruct single photon emission computerized tomography (SPECT) data are usually based on one of two principles: filtered backprojection and iterative methods. In this paper a different algorithm, applying an artificial neural network (multilayer perception) and error backpropagation as training method are used to reconstruct transaxial slices from SPECT data. The algorithm was implemented on an Elscint XPERT workstation (i486, 50 MHz), used as a routine digital image processing tool in our departments. Reconstruction time for a 64 x 64 matrix is approximately 45 s/transaxial slice. The algorithm has been validated by a mathematical model and tested on heart and Jaszczak phantoms. Phantom studies and very first clinical results ((111)In octreotide SPECT, 99mTc MDP bone SPECT) show in comparison with filtered backprojection an enhancement in image quality. PMID:10076982

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

    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)

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

    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.

  7. A prospective evaluation of thallium-201 single photon emission computerized tomography for brain tumor burden

    Purpose: The follow-up of patients with malignant brain tumors after surgery, radiation, and/or chemotherapy has been inadequate for evaluating brain tumor burden using computerized tomography (CT) or magnetic resonance imaging (MRI). Thallium-201 has been shown to concentrate in viable tumor, and Tl-201 single photon emission computerized tomography (SPECT) imaging can identify tumor burden more accurately than CT. Methods and Materials: Thirty-one patients with glioblastoma and three patients with low grade astrocytoma were studied with Tl-201 SPECT. Histololgic diagnosis was obtained in all patients by biopsy and all patients had CT scans within 2 weeks of the SPECT study. Seventeen patients were followed with one or more SPECT and CT evaluations. Results: Single photon emission computerized tomography studies, after surgery, radiotherapy, and/or chemotherapy, were more accurate than CT in identifying progression or regression of disease. Twenty-three patients had evidence of disease and 11 patients had no evidence of recurrent disease in the initial Tl-201 SPECT study following therapy. Computerized tomography identified 20 of the 23 patients with disease and 6 of 11 patients with no recurrent disease. Follow-up with Tl-201 SPECT in 17 patients suggested progression of disease in 9 patients, while CT showed progression in only 3 patients. Clinical examinations and repeat CT studies confirmed the accuracy of Tl-201 SPECT images. Conclusion: We found Tl-201 SPECT more accurate than CT scans in a prospective evaluation of 34 patients with brain tumor. Follow-up studies with both Tl-201 SPECT and CT imaging in 17 patients demonstrated that SPECT was more reliable than CT in identifying progression, improvement, or no change in brain tumor burden

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

    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.

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

    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.

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

    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...

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

    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...

  12. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  13. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    Tommila, J.; Hakkarainen, T. V.; Schramm, A., E-mail: andreas.schramm@tut.fi; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland); Belykh, V. V.; Sibeldin, N. N. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Heinonen, E. [Center of Microscopy and Nanotechnology, University of Oulu, P.O. Box 7150, FIN-90014 Oulu (Finland)

    2014-05-26

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  14. Statistical evaluation of single-photon emission computed tomography image using smoothed bootstrap method

    Many of the neurodegenerative diseases associated with a decrease in regional cerebral blood flow (rCBF) are untreatable, and the appropriate therapeutic strategy is to slow the progression of the disease. Therefore, it is important that a definitive diagnosis is made as soon as possible when such diseases are suspected. Diagnostic imaging methods, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT), play an important role in such a definitive diagnosis. Since several problems arise when evaluating these images visually, a procedure to evaluate them objectively is necessary, and studies of image analyses using statistical evaluations have been suggested. However, the assumed data distribution in a statistical procedure may occasionally be inappropriate. Therefore, to evaluate the decrease of rCBF, it is important to use a statistical procedure without assumptions about the data distribution. In this study, we propose a new procedure that uses nonparametric or smoothed bootstrap methods to calculate a standardized distribution of the Z-score without assumptions about the data distribution. To test whether the judgment of the proposed procedure is equivalent to that of an evaluation based on the Z-score with a fixed threshold, the procedure was applied to a sample data set whose size was large enough to be appropriate for the assumption of the Z-score. As a result, the evaluations of the proposed procedure were equivalent to that of an evaluation based on the Z-score. (author)

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

    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.

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

    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

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

    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)

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

    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.

  19. Astigmatic single photon emission computed tomography imaging with a displaced center of rotation

    A filtered backprojection algorithm is developed for single photon emission computed tomography (SPECT) imaging with an astigmatic collimator having a displaced center of rotation. The astigmatic collimator has two perpendicular focal lines, one that is parallel to the axis of rotation of the gamma camera and one that is perpendicular to this axis. Using SPECT simulations of projection data from a hot rod phantom and point source arrays, it is found that a lack of incorporation of the mechanical shift in the reconstruction algorithm causes errors and artifacts in reconstructed SPECT images. The collimator and acquisition parameters in the astigmatic reconstruction formula, which include focal lengths, radius of rotation, and mechanical shifts, are often partly unknown and can be determined using the projections of a point source at various projection angles. The accurate determination of these parameters by a least squares fitting technique using projection data from numerically simulated SPECT acquisitions is studied. These studies show that the accuracy of parameter determination is improved as the distance between the point source and the axis of rotation of the gamma camera is increased. The focal length to the focal line perpendicular to the axis of rotation is determined more accurately than the focal length to the focal line parallel to this axis. copyright 1998 American Association of Physicists in Medicine

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

    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

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

    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.)

  2. Quantification of left ventricular size on exercise thallium-201 single-photon emission tomography

    The purposes of this study were to determine whether quantification of the left ventricular size on exercise thallium-201 single-photon emission tomography (SPET) correlates with echocardiographic measurements, whether the quantification reflects the severity of coronary artery disease, and whether it can provide supplementary information regarding the severity of coronary artery disease. In 42 control subjects and 110 patients who underwent coronary angiography, we performed exercise 201Tl SPET and quantified six non-regional markers: Lung 201Tl uptake on an initial planar image (Lung/Heart), left ventricular width on a tomogram (Width), change in the Width from the initial to delayed tomograms (ΔWidth), count ratio of the left ventricular cavity to the myocardium (C/M), count ratio of the lung to the myocardium (L/M), and count ratio of the lung to the left ventricular cavity (L/C). In 76 patients, furthermore, the Width was compared with echocardiographic measurements. The Width correlated with echocardiographic measurements (P201Tl SPET correlated with echocardiogrpahic measurements and reflected the severity of coronary artery disease, but may be replaced with quantitation of the lung 201Tl uptake. (orig.)

  3. Evaluation of auto region of interest settings for single photon emission computed tomography findings

    It has been noted that the manual settings of region of interest (ROI) to the single-photon-emission-computed-tomography (SPECT) slice lacked objectivity when the fixed quantity value of regional cerebral blood flow (rCBF) was measured previously. Therefore, we jointly developed software Brain ROI' with Daiichi Radioisotope Laboratories, Ltd. (Present name: FUJIFILM RI Pharma Co., Ltd.) The software normalized an individual brain to a standard brain template by using Statistical Parametric Mapping 2 (SPM 2) of the easy Z-score Imaging System ver. 3.0 (eZIS Ver. 3.0), and the ROI template was set to a specific slice. In this study, we evaluated the accuracy of this software with an ROI template that we made of useful size and shape, in some clinical samples. The method of automatic setting of ROI was the objective. However, we felt that we should use the shape of the ROI template without the influence of brain atrophy. Moreover, we should see normalization of the individual brain and confirm the accuracy of normalization. When normalization failed, we should partially correct the ROI or set everything by manual operation for the operator. However, it was thought that this software was useful if the tendency was understood because examples of failure were few. (author)

  4. [Restoration filtering based on projection power spectrum for single-photon emission computed tomography].

    Kubo, N

    1995-04-01

    To improve the quality of single-photon emission computed tomographic (SPECT) images, a restoration filter has been developed. This filter was designed according to practical "least squares filter" theory. It is necessary to know the object power spectrum and the noise power spectrum. The power spectrum is estimated from the power spectrum of a projection, when the high-frequency power spectrum of a projection is adequately approximated as a polynomial exponential expression. A study of the restoration with the filter based on a projection power spectrum was conducted, and compared with that of the "Butterworth" filtering method (cut-off frequency of 0.15 cycles/pixel), and "Wiener" filtering (signal-to-noise power spectrum ratio was a constant). Normalized mean-squared errors (NMSE) of the phantom, two line sources located in a 99mTc filled cylinder, were used. NMSE of the "Butterworth" filter, "Wiener" filter, and filtering based on a power spectrum were 0.77, 0.83, and 0.76 respectively. Clinically, brain SPECT images utilizing this new restoration filter improved the contrast. Thus, this filter may be useful in diagnosis of SPECT images. PMID:7776546

  5. Restoration filtering based on projection power spectrum for single-photon emission computed tomography

    To improve the quality of single-photon emission computed tomographic (SPECT) images, a restoration filter has been developed. This filter was designed according to practical 'least squares filter' theory. It is necessary to know the object power spectrum and the noise power spectrum. The power spectrum is estimated from the power spectrum of a projection, when the high-frequency power spectrum of a projection is adequately approximated as a polynomial exponential expression. A study of the restoration with the filter based on a projection power spectrum was conducted, and compared with that of the 'Butterworth' filtering method (cut-off frequency of 0.15 cycles/pixel), and 'Wiener' filtering (signal-to-noise power spectrum ratio was a constant). Normalized mean-squared errors (NMSE) of the phantom, two line sources located in a 99mTc filled cylinder, were used. NMSE of the 'Butterworth' filter, 'Wiener' filter, and filtering based on a power spectrum were 0.77, 0.83, and 0.76 respectively. Clinically, brain SPECT images utilizing this new restoration filter improved the contrast. Thus, this filter may be useful in diagnosis of SPECT images. (author)

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

    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)

  7. Critical examination of the uniformity requirements for single-photon emission computed tomography.

    O'Connor, M K; Vermeersch, C

    1991-01-01

    It is generally recognized that single-photon emission computed tomography (SPECT) imposes very stringent requirements on gamma camera uniformity to prevent the occurrence of ring artifacts. The purpose of this study was to examine the relationship between nonuniformities in the planar data and the magnitude of the consequential ring artifacts in the transaxial data, and how the perception of these artifacts is influenced by factors such as reconstruction matrix size, reconstruction filter, and image noise. The study indicates that the relationship between ring artifact magnitude and image noise is essentially independent of the acquisition or reconstruction matrix sizes, but is strongly dependent upon the type of smoothing filter applied during the reconstruction process. Furthermore, the degree to which a ring artifact can be perceived above image noise is dependent on the size and location of the nonuniformity in the planar data, with small nonuniformities (1-2 pixels wide) close to the center of rotation being less perceptible than those further out (8-20 pixels). Small defects or nonuniformities close to the center of rotation are thought to cause the greatest potential corruption to tomographic data. The study indicates that such may not be the case. Hence the uniformity requirements for SPECT may be less demanding than was previously thought. PMID:2046604

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

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

  9. Quantification of leg muscle perfusion using thallium-201 single photon emission computed tomography

    The purpose of this study is to quantify leg muscle perfusion with 201Tl single photon emission computed tomography (SPECT). Six normal controls and 21 patients with peripheral arterial disease underwent this examination. Thallium-201 leg SPECT of both stress and redistribution was performed using a dual-headed digital gamma camera. Each slice of transverse images was normalized with pixels and whole-body counts. In normal controls, the activity of posterior tibial muscle components was significantly higher than that of anterior tibial muscle components (p less than 0.001). In 14 components, where patients had insignificant lesions, profile curves were normal in 10 (71%). In 62 components, where patients had arteriographically significant lesions, stress profile curves were abnormal in 57 (92%) compared with normal controls. Approximately, in half (28/62) components which had significant lesions, profile curves showed redistribution after 3 hr compared with normal redistribution curves. In three patients who underwent successful bypass graftings, the activity of each muscle component returned to a normal range

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

    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)

  11. Gated single-photon emission computed tomography detects subendocardial ischemia in hypertrophic cardiomyopathy

    Patients with hypertrophic cardiomyopathy (HCM) sometimes develop subendocardial ischemia (SEI) in the left ventricle (LV). In the present study it was examined whether volumetric variables obtained by gated single-photon emission computed tomography (SPECT) are useful in detecting exercise-induced SEI in patients with HCM. Exercise 99mTc-tetrofosmin myocardial scintigraphy was performed in 26 HCM patients having non-obstruction and mild hypertrophy with a ventricular septal thickness ≤20 mm. SEI was quantified using software developed previously, and the results were correlated with volumetric variables obtained using Quantitative Gated SPECT software. Exercise-induced percentage change in LV end-systolic volume was higher in 9HCM patients with SEI (25.8±3.1%) than in 17 patients without (10.0±25% p=0.009), although the percentage change in LV end-diastolic volume was similar in the 2 groups. The receiver-operator characteristics curve of the percentage changes in LV end-systolic volume for the detection of SEI showed that the optimal cutoff was 17%. This cutoff point yielded a good diagnostic value for the presence of SEI with a sensitivity of 89%, specificity 82%, and likelihood ratio 5.04. Gated SPECT technique is useful in detecting SEI during exercise in a select population of HCM patients. (author)

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

    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

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

    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)

  14. Pinhole single-photon emission tomography reconstruction based on median root prior

    The maximum likelihood expectation maximisation (ML-EM) algorithm can be used to reduce reconstruction artefacts produced by filtered backprojection (FBP) methods in pinhole single-photon emission tomography (SPET). However, ML-EM suffers from noise propagation along iterations, which leads to quantitatively unpleasant reconstruction results. To avoid this increase in noise, the median root prior (MRP) algorithm for pinhole SPET was implemented. Projection data of a line source and Picker's thyroid phantom were collected using a single-head gamma camera with a pinhole collimator. MRP was added to existing pinhole ML-EM reconstruction algorithm and the phantom studies were reconstructed using MRP, ML-EM and FBP for comparison. Coefficients of variation, contrasts and full-widths at half-maximum were calculated and showed a clear reduction in noise without significant loss of resolution or decrease in contrast when MRP was applied. MRP also produced visually pleasing images even with high iteration numbers, free of the checkerboard-type noise patterns which are typical of ML-EM images. (orig.)

  15. Brain Single Photon Emission Computed Tomography in Anosmic Subjects Ater Closed Head Trauma

    Roozbeh Banan

    2011-01-01

    Full Text Available Anosmia following head trauma is relatively common and in many cases is persistent and irreversible. The ability to objectively measure such a decline in smelling, for both clinical and medicolegal goals, is very important. The aim of this study was to find results of brain Single Photon Emission Computed Tomography (SPECT in anosmic subjects after closed head trauma. This case-control cross sectional study was conducted in a tertiary referral University Hospital. The brain perfusion state of nineteen anosmic patients and thirteen normal controls was evaluated by means of the SPECT with 99mtc- ECD infusion- before and after olfactory stimulation. The orbitofrontal lobe of the brain was assumed as the region of interest and changes in perfusion of this area before and after the stimulations were compared in two groups. The mean of brain perfusion in controls before and after the stimulation was 8.26% ± 0.19% and 9.89% ± 0.54%, respectively (P < 0.0001. Among patients group, these quantities were 7.97% ± 1.05% and 8.49% ± 1.5%, respectively (P < 0.004. The difference between all the measures in cases and controls were statistically significant (P < 0.0001. There were no differences in age and sex between two groups. The brain SPECT is an objective technique suitable for evaluating anosmia following the head trauma and it may be used with other diagnostic modalities

  16. Single-photon emission tomography imaging of monoamine transporters in impulsive violent behaviour

    Several studies have shown that impulsive violent and suicidal behaviour is associated with a central serotonin deficit, but until now it has not been possible to use laboratory tests with high sensitivity and specificity to study this kind of deficit or to localize the sites of serotonergic abnormalities in the living human brain. The aim of this study was to test the hypothesis that monoamine transporter density in brain is decreased in subjects with impulsive violent behaviour. We studied serotonin (5-HT) and dopamine (DA) transporter specific binding in 52 subjects (21 impulsive violent offenders, 21 age- and sex-matched healthy controls, and ten non-violent alcoholic controls) with single-photon emission tomography (SPET) using iodine-123-labelled 2β-carbomethoxy-3β(4-iodophenyl)tropane ([123I]β-CIT) as the tracer. The blind quantitative analysis revealed that the 5-HT specific binding of [123I]β-CIT in the midbrain of violent offenders was lower than that in the healthy control subjects (P<0.005; t test) or the non-violent alcoholics (P<0.05). The results imply that habitual impulsive aggressive behaviour in man is associated with a decrease in the 5-HT transporter density. (orig.)

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

    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

  18. Single photon emission tomography approach for online patient dose assessment in boron neutron capture therapy

    A tomographic imaging system for the measurement of the spatial distribution of the absorbed dose during a Boron Neutron Capture Therapy (BNCT) session is presented. The 10B(n,α)7Li boron neutron capture reaction produces a 478 keV gamma ray in 94% of the cases. Therefore its detection can serve as a basis for a non-invasive online absorbed dose determination since the dose absorbed by the tumor and healthy tissue strongly depends on the boron uptake and the neutron flux. For this purpose, a dedicated tomographic imaging system based on Single Photon Emission Computed Tomography is proposed. Monte Carlo numerical simulations are used for the system design aimed to have a spatial resolution of 1 cm. Prototypes based on CdZnTe semiconductor detectors and LaBr3(Ce) scintillators with optimized shielding were designed with Monte Carlo simulations. They were built and tested in reactor and accelerator based BNCT facilities. A projection of a phantom with two tumors with 400 ppm of 10B was successfully measured at the accelerator facility of the University of Birmingham. (author)

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

    Terao, Shin-ichi; Sobue, Gen; Higashi, Naoki; Takahashi, Masahiko; Suga, Hidemichi; Mitsuma, Terunori [Aichi Medical Univ., Nagakute (Japan)

    1995-03-01

    {sup 123}I-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).

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

    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)

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

    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)

  2. Regional brain hematocrit in stroke by single photon emission computed tomography imaging

    Nineteen studies on 18 subjects were performed by single photon emission computed tomography (SPECT) of the head after the successive intravenous administration of a plasma label (/sup 99m/Tc-human serum albumin [HSA]) and /sup 99m/Tc-labeled autologous red blood cells (RBC). Two sets of cerebral tomographic sections were generated: for cerebral /sup 99m/Tc-HSA alone and for combined /sup 99m/Tc-HSA and /sup 99m/Tc-RBC. By relating counts in regions of interest from the cerebral tomograms to counts from blood samples obtained during each tomographic acquisition, regional cerebral haematocrit (Hct) was calculated by the application of a simple formula. Results show 1) lower cerebral Hct than venous Hct (ratio of HCT brain/Hct venous 0.65-0.90) in all subjects, and 2) comparison between right and left hemisphere Hct in 3/3 normal subjects, 6/6 patients with transient ischaemic attacks and 3/8 patients with stroke showed no significant difference. However, in 3/8 patients with stroke (most recent strokes) significant differences were found, the higher Hct value corresponding to the affected side

  3. Imaging of dopamine transporters in rats using high-resolution pinhole single-photon emission tomography

    To date, the vast majority of investigations on the dopaminergic system in small animals have been in vitro studies. In comparison with in vitro studies, single-photon emission tomography (SPET) or positron emission tomography (PET) imaging of the dopaminergic system in small animals has the advantage of permitting repeated studies within the same group of animals. Dopamine transporter imaging is a valuable non-invasive tool with which to investigate the integrity of dopaminergic neurons. The purpose of this study was to investigate the feasibility of assessing dopamine transporter density semi-quantitatively in rats using a recently developed high-resolution pinhole SPET system. This system was built exclusively for imaging of small animals. In this unique single-pinhole system, the animal rotates instead of the collimated detector. The system has proven to have a high spatial resolution. We performed SPET imaging with [123I]FP-CIT to quantify striatal dopamine transporters in rat brain. In all seven studied control rats, symmetrical striatal binding to dopamine transporters was seen 2 h after injection of the radiotracer, with striatal-to-cerebellar binding ratios of approximately 3.5. In addition, test/retest variability of the striatal-to-cerebellar binding ratios was studied and found to be 14.5%. Finally, in unilaterally 6-hydroxydopamine-lesioned rats, striatal binding was only visible on the non-lesioned side. Quantitative analysis revealed that striatal-to-cerebellar SPET ratios were significantly lower on the lesioned (mean binding ratio 2.2±0.2) than on the non-lesioned (mean ratio 3.1±0.4) side. The preliminary results of this study indicate that semi-quantitative assessment of striatal dopamine transporter density using our recently developed high-resolution single-pinhole SPET system is feasible in living rat brain. (orig.)

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

    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. Single-photon quadratic optomechanics

    Jie-Qiao Liao; Franco Nori

    2013-01-01

    We present exact analytical solutions to study the coherent interaction between a single photon and the mechanical motion of a membrane in quadratic optomechanics. We consider single-photon emission and scattering when the photon is initially inside the cavity and in the fields outside the cavity, respectively. Using our solutions, we calculate the single-photon emission and scattering spectra, and find relations between the spectral features and the system's inherent parameters, such as: the...

  6. 89Sr bremsstrahlung single photon emission computed tomography using a gamma camera for bone metastases

    Strontium-89 chloride (89Sr) bremsstrahlung single photon emission computed tomography (SPECT) imaging was evaluated for detecting more detailed whole body 89Sr distribution. 89Sr bremsstrahlung whole body planar and merged SPECT images were acquired using two-detector SPECT system. Energy window A (100 keV ± 50%) for planar imaging and energy window A plus adjacent energy window B (300 keV ± 50%) for SPECT imaging were set on the continuous spectrum. Thirteen patients with multiple bone metastases were evaluated. Bone metastases can be detected with 99mTc-HMDP whole body planar and merged SPECT images and compared with 89Sr bremsstrahlung whole body planar and merged SPECT images. Based on the location of metastatic lesions seen as hot spots on 99mTc-HMDP images as a reference, the hot spots on 89Sr bremsstrahlung images were divided into the same bone parts as 99mTc-HMDP images (a total of 35 parts in the whole body), and the number of hot spots were counted. We also evaluated the incidence of extra-osseous uptakes in the intestine on 89Sr bremsstrahlung whole body planar images. A total of 195 bone metastatic lesions were detected in both 99mTc-HMDP whole body planar and merged SPECT images. Detection of hot spot lesions in 89Sr merged SPECT images (127 of 195; 66%) was more frequent than in 89Sr whole body planar images (108 of 195; 56%), based on metastatic bone lesions in 99mTc-HMDP whole body planar and merged SPECT images. A large intestinal 89Sr accumulation was detected in 5 of the 13 patients (38%). 89Sr bremsstrahlung-merged SPECT imaging could be more useful for detailed detection of whole body 89Sr distribution than planar imaging. Intestinal 89Sr accumulation due to 89Sr physiologic excretion was detected in feces for 4 days after tracer injection. (author)

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

    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)

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

    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.

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

    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

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

    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.

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

    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

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

    Using proton magnetic resonance spectroscopy (1H-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 cm3 (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)

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

    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.)

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

    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.

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

    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

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

    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.)

  17. Automatic segmentation of dynamic neuroreceptor single-photon emission tomography images using fuzzy clustering

    The segmentation of medical images is one of the most important steps in the analysis and quantification of imaging data. However, partial volume artefacts make accurate tissue boundary definition difficult, particularly for images with lower resolution commonly used in nuclear medicine. In single-photon emission tomography (SPET) neuroreceptor studies, areas of specific binding are usually delineated by manually drawing regions of interest (ROIs), a time-consuming and subjective process. This paper applies the technique of fuzzy c-means clustering (FCM) to automatically segment dynamic neuroreceptor SPET images. Fuzzy clustering was tested using a realistic, computer-generated, dynamic SPET phantom derived from segmenting an MR image of an anthropomorphic brain phantom. Also, the utility of applying FCM to real clinical data was assessed by comparison against conventional ROI analysis of iodine-123 iodobenzamide (IBZM) binding to dopamine D2/D3 receptors in the brains of humans. In addition, a further test of the methodology was assessed by applying FCM segmentation to [123I]IDAM images (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio] benzyl alcohol) of serotonin transporters in non-human primates. In the simulated dynamic SPET phantom, over a wide range of counts and ratios of specific binding to background, FCM correlated very strongly with the true counts (correlation coefficient r2>0.99, P123I]IBZM data comparable with manual ROI analysis, with the binding ratios derived from both methods significantly correlated (r2=0.83, P<0.0001). Fuzzy clustering is a powerful tool for the automatic, unsupervised segmentation of dynamic neuroreceptor SPET images. Where other automated techniques fail completely, and manual ROI definition would be highly subjective, FCM is capable of segmenting noisy images in a robust and repeatable manner. (orig.)

  18. Blood flow measurement in human brain by 133Xe inhalation and single photon emission computed tomography

    Regional cerbral blood flow (rCBF) was studied tomographically in 39 volunteers in the resting state by single photon emission computed tomography with inhalation of 133Xe. In each study, rCBF in 3 slices of 2 cm thickness was measured simultaneously and changes of radioactivity in the brain were stored on the magnetic disk in 32 x 32 matrix. Activity in the arterial blood was measured by a stationary collimated scintillation detector kept over the upper chest on the right side. The algorithm for calculation of tomographic rCBF was based on a combination of ''sequence of picture method'' and ''early picture method''. Mean rCBF and its standard deviation were obtained in each pixel calculated from the rCBF value. The tomographic rCBF map having a resolution element of 17 x 17 x 20 mm were symmetrical in left and right pattern. The average cerebral and, cerebellar blood flow was 56+-8 and 54+-6 ml/100g/min respectively. Correlation between rCBF and PaCO2 was significant (P<0.01; r=0.7) and the one between rCBF and age was also significant (P<0.05; r=-0.3). When visual activation was made in one volunteer, rCBF in the occipital lobe increased and a slight increase was also noted in the frontal area. In auditory activation, rCBF in the temporal lobe increased on both sides. In stroke patients, abnormal findings appeared earlier in the rCBF study than in X-ray CT scan. (J.P.N.)

  19. Rapid renal single-photon emission tomography by continuous infusion of iridium-191m

    Continuous infusion of iridium-191m (t1/2 = 5 s), produced with an 191Os/191mIr generator, was used to obtain rapid high-resolution single-photon emission tomography (SPET) of renal blood flow in the rabbit. SPET scans of the abdomen were obtained with a triple-detector SPET system (MS3, Siemens Gammasonics). The generator was eluted at a flow rate of 3 ml/min, which delivered a steady-state dose of 170 MBq (4.5 mCi) of 191mIr. The total 191Os breakthrough was 850 kBq (23 μCi). A 5-min SPET acquisition recorded a total of 2.8 million counts, resulting in images of high technical quality. Volume-rendered images clearly showed the abdominal aorta, splenic artery, spleen, renal arteries, kidneys and splanchnic vasculature. Tomographic slices through the kidneys revealed tracer primarily within the renal cortices without visualization of the collecting system. The estimated effective dose equivalent for a 5 min infusion of 191mIr at a steady-state dose of 170 MBq is 0.74 mSv compared with 2.7 mSv from a 170 MBq dose of 99mTc-DMSA. This study demonstrates the feasibility of high-resolution SPET of regional renal perfusion in the rabbit by continuous intravenous infusion of 191mIr. The renal distribution of continuously infused 191mIr is largely within the cortices, with minimal or no detectable activity in the region of the renal pelvicalyceal system. Using this technique, cortical renal SPET can be completed much more rapidly (191mIr that occur in animal models of altered renal perfusion. (orig.)

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

    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)

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

    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

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

    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

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

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

  4. Regional cerebral blood flow in status epileptics measured by single photon emission computed tomography (SPECT)

    We have performed single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amineoxime (HM-PAO) to evaluate regional cerebral blood flow (rCBF) in status epileptics (SE) caused by a cerebral vascular accident. In addition, we have discussed the neurophysiology of SE based on the SPECT findings. A total of sixteen patients (5 males and 11 females, average age; 78.2 years old) with SE who were suffering from prolonged consciousness disturbance were investigated. When SPECT was performed in the ictal state, there was a remarkable increase in radio isotope (RI) uptake at the focus which correlated well with EEG findings. However, in other cortical regions, basal ganglia and thalamus, there was a relatively demonstrated decrease in RI uptake compared with that of the focus. Additionally in the interictal state, we found a decrease in RI uptake in the epileptic foci and normal recovery of the RI uptake level in other cerebral regions. We speculate that these characteristic patterns of cerebral blood flow distribution shown by SPECT scans in the ictal state reflect the state of consciousness disturbance due to SE. In general, in the elderly, it is difficult to make a differential diagnosis between prolonged consciousness disturbance due to nonconvulsive SE and other diseases such as cardiovascular diseases, dehydration, metabolic disorder, etc. Nevertheless, nonconvulsive SE causes diffuse cell loss and irreversible brain damage. Therefore the elderly who have suffered from prolonged consciousness disturbance due to SE need an exact diagnosis and immediate medical treatment. When we diagnose a nonconvulsive SE, the characteristic findings of SPECT scans in the ictal state are very clear and useful. In conclusion, SPECT is a very simple and non-invasive method that demonstrates abnormalities of brain function exactly. Therefore, we should perform not only EEC but also SPECT scans when making a diagnosis of SE. (author)

  5. Feasibility and value of fully 3D Monte Carlo reconstruction in single photon emission computed tomography

    The accuracy of Single Photon Emission Computed Tomography (SPECT) images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using 4 methods: filtered backprojection (FBP), MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20 to 70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation. (authors)

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

    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)

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

    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...... emission computed tomography (SPECT/MPI). Sixteen centres enroled 381 patients who underwent combined CTA-CTP and SPECT/MPI prior to conventional coronary angiography. All four image modalities were analysed in blinded independent core laboratories. The prevalence of obstructive CAD defined by combined ICA...... 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...

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

    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 ∼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

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

    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.

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

    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.

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

    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...

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

    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...

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

    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...

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

    Jain, Sachin; Karunanithi, Sellam; Agarwal, Krishan Kant; Kumar, Ganesh; Roy, Shambo Guha; Tripathi, Madhavi

    2014-01-01

    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 navicula...

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

    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...

  16. Brain hypoperfusion on Tc-99m-ethylene dicysteine diethyl ester single-photon emission computed tomography in Hashimoto's encephalopathy

    We present a 17-year-old female, previously diagnosed of autoimmune hyperthyroidism who had an acute neurological episode and presented high antithyroid antibodies titers, cerebral spinal fluid and electroencephalogram changes. 99mTc ethylene dicysteine diethyl ester brain single-photon emission computed tomography (SPECT) showed global and patchy hypoperfusion. With glucocorticoid therapy, clinical symptoms disappeared; there was a decrease in antithyroid antibody levels and repeat brain SPECT revealed improvement of perfusion. (author)

  17. Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

    Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

    1998-01-01

    Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

  18. Physical factors affecting single photon emission computed tomography (SPECT) applied in nuclear medicine

    many physical factors degrade single photon emission computed tomography (SPECT) images both qualitatively and quantitatively. Physical properties important for the assessment of the potential of emission computed tomography implemented by collimated detector systems include sensitivity, statistical and angular sampling requirements, attenuation compensation, resolution, uniformity, and multisection design constraints. SPECT has highlighted the used to improve gamma camera performance. Flood field nonuniformity is translated into tomographic the need to improve gamma camera performance. Flood field nonuniformity is translated into tomographic images as major artifacts because it distorts the data obtained at each projection. Also, poor energy resolution translates directly into degraded spatial resolution through reduced ability to reject scattered photons on the basic of pluses height analysis. The aim of this work is study the different and most important acquisition and processing parameters, which affect the quality of the SPECT images. The present study investigates the various parameters effecting SPECT images and experimental results demonstrate that: daily uniformity checks and evaluation are essential to ensure that the SPECT system is working properly. The Core used in the reconstruction process could be correct to avoid data misalignment. 60 mumblers of views gave the best image quality, rather than 20 or 30 views. Time per view (TPV) 30 or 20 sec gave a good image quality, rather than high-resolution collimator, is recommended in order to provide good spatial resolution. On the other hand patient motion could cause serious reconstruction artifacts. A cine display is recommended to identify movement artifacts. In the case of matrix size, matrix 128x128 give the best resolution than matrix 64x64. Energy window width, 15% compared with the standard 20% improved the resolution. Butter worth filter (cut off 0.57 cyc/cm with order 6 ) give the best resolution

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

    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

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

    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

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

    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.)

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

    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.)

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

    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

  4. The role of scintimammography with 99MTC-MIBI in evaluation of the breast lesions

    Introduction: The aim of this study was to determine diagnostic value of prone lateral 99mTc-MIBI scintigraphy in detection of primary breast cancer in patients with breast lesions. Materials and methods: We evaluated 142 patients with breast lesions and/or suspicious mammographic findings. In all patients, the diagnosis was established by pathology. Pattern of abnormal MIBI uptake ( focal or diffuse ) and quantitative measurement of the Ratio of Lesion to normal tissue uptake( T/N Ratio) was recorded. All lesions with abnormal focal uptake with T/N Ratio of more than 1.30 were considered as malignant lesion. Cases with normal homogeneous or abnormal diffusely increased uptake in the breast tissue were interpreted as negative for malignant lesion. Results: Of 142 patients, histopathologic study of 36 cases showed Malignancy which 34 cases of them had Positive MIBI scan. Of 106 cases of negative pathology ,cases had Negative MIBI scintimammography. Analysis of the findings showed high sensitivity, Specificity, accuray and Negative predictive value for 99m-MIBI scintimammography in detection of malignant breast lesion. Conclusion: We concluded that MIBI Scan can be used as complementary or even competitory imaging to the mammography in the evaluation of the breast lesions. (authors)

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

    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

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

    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

  7. Early and delayed single photon emission CT in various cerebral diseases using N-isopropyl-p-(123I)iodoamphetamine

    Early and delayed single photon emission computed tomography (SPECT) using N-isopropyl-p-(123I)iodoamphetamine (IMP) was performed on 28 subjects (2 normal, 12 with cerebrovascular diseases and 14 with brain tumors) to evaluate the reversibility of the cerebral abnormality and cerebral viability. The results were compared with X-ray T, 99mTc brain scintigraphy and rCBF by 133Xe inhalation method. Three types of IMP kinetics were observed. Initial hypoactivity that changed over 4 to 6 hours approaching a normal pattern suggests a hypofunctional parenchyma without significant tissue damage: Long-lasting abnormalities on IMP SPECT indicates cellular damage. (orig.)

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

    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

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

    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

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

    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.)

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

    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.)

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

    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.

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

    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.

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

    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

  15. Single photon emission tomography using sup(99m)Tc-HM-PAO in the investigation of dementia

    Single photon emission tomographic imaging of the brain using sup(99m)Tc HM-PAO was carried out in patients with a clinical diagnosis of Alzheimer's disease, non-Alzheimer frontal-lobe dementia, and progressive supranuclear palsy. Independent assessment of reductions in uptake revealed posterior hemisphere abnormalities in the majority of the Alzheimer group, and selective anterior hemisphere abnormalities in both other groups. The findings were consistent with observed patterns of mental impairment. The imaging technique has potential value in the differential diagnosis of primary cerebral atrophy. (author)

  16. Single photon emission tomography using sup(99m)Tc-HM-PAO in the investigation of dementia

    Neary, D.; Snowden, J.S.; Shields, R.A.; Burjan, A.W.I.; Northen, B.; Macdermott, N.; Prescott, M.C.; Testa, H.J.

    1987-09-01

    Single photon emission tomographic imaging of the brain using sup(99m)Tc HM-PAO was carried out in patients with a clinical diagnosis of Alzheimer's disease, non-Alzheimer frontal-lobe dementia, and progressive supranuclear palsy. Independent assessment of reductions in uptake revealed posterior hemisphere abnormalities in the majority of the Alzheimer group, and selective anterior hemisphere abnormalities in both other groups. The findings were consistent with observed patterns of mental impairment. The imaging technique has potential value in the differential diagnosis of primary cerebral atrophy.

  17. Small animal imaging by single photon emission using pinhole and coded aperture collimation

    The aim of this paper is to investigate the basic properties and limits of the small animal imaging systems based on single photon detectors. The detectors for radio imaging of small animals are challenging because of the very high spatial resolution needed, possibly coupled with high efficiency to allow dynamic studies. These performances are hardly attainable with single photon technique because of the collimator that limits both spatial resolution and sensitivity. In this paper we describe a simple desktop detector based on pixellated NaI(Tl) scintillator array coupled with a pinhole collimator and a PSPMT, the Hamamatsu R2486. The limits of such systems as well as the way to overcome them will be shown. In fact better light sampling at the anode level would allow better pixel identification for higher number of pixel that is one of the parameters defining the image quality. Also the spatial resolution would improve. The performances of such layout are compared with others using PSPMTs differing from R2486 for the light sampling at the anode level and different areas. We show how a further step, namely the substitution of the pinhole collimator with a coded aperture, will allow a great improvement in system sensitivity while maintaining very good spatial resolution, possibly submillimetric. Calculations and simulations show that sensitivity would improve by a factor of 50

  18. Small animal imaging by single photon emission using pinhole and coded aperture collimation

    Garibaldi, F.; Accorsi, R.; Cinti, M.N.; Colilli, S.; Cusanno, F.; De Vincentis, G.; Fortuna, A.; Girolami, B.; Giuliani, F.; Gricia, M.; Lanza, R.; Loizzo, A.; Loizzo, S.; Lucentini, M.; Majewski, S.; Santavenere, F.; Pani, R.; Pellegrini, R.; Signore, A.; Scopinaro, F.

    2005-06-01

    The aim of this paper is to investigate the basic properties and limits of the small animal imaging systems based on single photon detectors. The detectors for radio imaging of small animals are challenging because of the very high spatial resolution needed, possibly coupled with high efficiency to allow dynamic studies. These performances are hardly attainable with single photon technique because of the collimator that limits both spatial resolution and sensitivity. In this paper we describe a simple desktop detector based on pixellated NaI(Tl) scintillator array coupled with a pinhole collimator and a PSPMT, the Hamamatsu R2486. The limits of such systems as well as the way to overcome them will be shown. In fact better light sampling at the anode level would allow better pixel identification for higher number of pixel that is one of the parameters defining the image quality. Also the spatial resolution would improve. The performances of such layout are compared with others using PSPMTs differing from R2486 for the light sampling at the anode level and different areas. We show how a further step, namely the substitution of the pinhole collimator with a coded aperture, will allow a great improvement in system sensitivity while maintaining very good spatial resolution, possibly submillimetric. Calculations and simulations show that sensitivity would improve by a factor of 50.

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

    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

  20. A novel phantom design for emission tomography enabling scatter- and attenuation-''free'' single-photon emission tomography imaging

    A newly designed technique for experimental single-photon emission tomography (SPET) and positron emission tomography (PET) data acquisition with minor disturbing effects from scatter and attenuation has been developed. In principle, the method is based on discrete sampling of the radioactivity distribution in 3D objects by means of equidistant 2D planes. The starting point is a set of digitised 2D sections representing the radioactivity distribution of the 3D object. Having a radioactivity-related grey scale, the 2D images are printed on paper sheets using radioactive ink. The radioactive sheets can be shaped to the outline of the object and stacked into a 3D structure with air or some arbitrary dense material in between. For this work, equidistantly spaced transverse images of a uniform cylindrical phantom and of the digitised Hoffman rCBF phantom were selected and printed out on paper sheets. The uniform radioactivity sheets were imaged on the surface of a low-energy ultra-high-resolution collimator (4 mm full-width at half-maximum) of a three-headed SPET camera. The reproducibility was 0.7% and the uniformity was 1.2%. Each rCBF sheet, containing between 8.3 and 80 MBq of 99mTcO4- depending on size, was first imaged on the collimator and then stacked into a 3D structure with constant 12 mm air spacing between the slices. SPET was performed with the sheets perpendicular to the central axis of the camera. The total weight of the stacked rCBF phantom in air was 63 g, giving a scatter contribution comparable to that of a point source in air. The overall attenuation losses were <20%. A second SPET study was performed with 12-mm polystyrene plates in between the radioactive sheets. With polystyrene plates, the total phantom weight was 2300 g, giving a scatter and attenuation magnitude similar to that of a patient study. With the proposed technique, it is possible to obtain ''ideal'' experimental images (essentially built up by primary photons) for comparison with

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

    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...

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

    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...

  3. Measurement of cerebral blood flow by single photon emission tomography: principles and application to functional studies of the language areas

    Quantitative measurement of cerebral blood flow by single photon emission computerized tomography (SPECT) is a new technique which is particularly suitable for routine studies of cerebro-vascular diseases. SPECT can be used to examine the deep structures of the brain and cerebellum. The functional areas of the brain, which have hitherto been only accessible by clinical-anatomical methods, can be imaged by this technique, based on the correlation between cerebral blood flow and metabolism. The demonstration of preferential activation of temporal and frontal zones in the left hemisphere by active speech stimulation confirms the general principles of hemispheric lateralization of cerebral functions. In addition to this role in studying the physiology of normal subjects, the technique has practical pathological applications. Knowledge of hemispheric lateralization of spoken language should be a pre-operative test for cerebral lesion when there is a risk that surgical intervention may produce irreversible neuropsychological lesions

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

    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)

  5. Cerebral perfusion inhomogeneities in schizophrenia demonstrated with single photon emission computed tomography and Tc99m-hexamethylpropyleneamineoxim

    Cerebral blood flow was measured in relative terms with Tc99m-hexamethylpropyleneamineoxim (HMPAO) and single photon emission computed tomography (SPECT) in 28 female schizophrenic patients (20 acute and 8 chronic) classified according to DSM-III. Eleven normals served as controls. The acute patients were classified according to positive and negative symptoms. Patients with predominantly positive symptoms showed by and large normal and homogeneous cerebral isotope uptake. Those with negative symptoms, and the chronic patients, showed inhomogeneous tracer uptake with multiple regions of hypoperfusion in slices 4-6 cm above the orbitomeatal line. The findings support in principle the notion that schizophrenia with negative or chronic symptoms does not affect the whole brain homogeneously. Brain imaging with Tc99m-HMPAO and SPECT might be used to distinguish various types of schizophrenia. (author)

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

    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

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

    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.)

  8. Single photon emission computed tomography with 123I-N-isopropyl-p-iodoamphetamine in three cases of neuroleptic malignant syndrome

    Three patients with neuroleptic malignant syndrome underwent single photon emission computd tomography (SPECT) with I-123-N-isopropyl-p-iodoamphetamine (I-123 IMP). In two patients, there was bilateral difference in tracer uptake on early images: decreased uptake in the right basal ganglion and increased uptake in the left basal ganglion. In the third patient, similar findings were seen on early images; however, in contrast to early images, delayed images showed more noticeable tracer uptake in the right basal ganglion than the left basal ganglion. These findings were not associated with the recovery from neuroleptic malignant syndrome. This suggested that some abnormality in the basal ganglion may be involved in the occurrence of neuroleptic malignant syndrome. SPECT with I-123 IMP was considered useful in searching for pathophysiology of neuroleptic malignant syndrome. (N.K.)

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

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

    obtained 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...... a single photon source. We have grown vertically oriented ZnSe NWs (with typical diameter of 10 nm) by molecular beam epitaxy on a ZnSe(111)B buffer layer. The growth of a ZnMgSe passivating shell increases the (otherwise weak) ZnSe near-band-edge luminescence by two orders of magnitude. This has...

  10. State of the art in emission tomography equipment: a brief overview of emergence of single photon emission computed tomography as a powerful clinical method in Bangladesh

    The current state of the art in the single photon emission computed tomography (SPECT) equipment is based on development over last 35 years including those items necessary to make the devices clinically useful in SPECT most of the development has involved rotating gamma cameras, since this device could also be used for conventional planner imaging. Recent advances involve the use of multi headed SPECT cameras and have led to substantial increase in image quality with this devices. (author) 12 refs

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

    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

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

    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.

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

    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.

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

    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 char...... 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....

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

    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...

  16. Engineered Quantum Dot Single Photon Sources

    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.

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

    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...

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

    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

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

    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

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

    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...

  1. Diagnosis of Pick's disease with N-isopropyl-p-[I-123] iodoamphetamine single photon emission computed tomography

    Single photon emission computed tomography (SPECT) using N-isopropyl-p-[I-123]iodoamphetamine (IMP) was performed in 3 patients with Pick's disease (PD) and one patient with Alzheimer's disease (AD). Early and delayed SPECT images were obtained at 20 min and 4 hr, respectively, after iv injection of IMP. In the group of PD patients, early images showed markedly decreased uptake of IMP in the area extending from the frontal to lateral lobes, which corresponded to atrophy as seen on concurrently available magnetic resonance imaging (MRI). On delayed images, there was a trend for slightly increased uptake of IMP when atrophy was milder on MRI. In the case of AD, markedly decreased uptake of IMP was bilaterally observed in the lateral, parietal, and occipital lobes. This was not seen as specific MRI appearance, but was consistent with previously reported features of positron emission computed tomography. The results suggest the usefulness of IMP-SPECT as an adjunctive method for differentiating PD from AD because of the two different SPECT appearances. (Namekawa, K.)

  2. Electrically pumped single-photon emission at room temperature from a single InGaN/GaN quantum dot

    We demonstrate a semiconductor quantum dot based electrically pumped single-photon source operating at room temperature. Single photons emitted in the red spectral range from single In0.4Ga0.6N/GaN quantum dots exhibit a second-order correlation value g(2)(0) of 0.29, and fast recombination lifetime ∼1.3 ±0.3 ns at room temperature. The single-photon source can be driven at an excitation repetition rate of 200 MHz.

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

    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

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

    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)

  5. Abnormal response to mental stress in patients with Takotsubo cardiomyopathy detected by gated single photon emission computed tomography

    Persistent abnormalities are usually not detected in patients with Takotsubo cardiomyopathy (TTC). Since sympathetically mediated myocardial damage has been proposed as a causative mechanism of TTC, we explored whether mental stress could evoke abnormalities in these patients. One month after an acute event, 22 patients fulfilling all TTC diagnostic criteria and 11 controls underwent resting and mental stress gated single photon emission computed tomography (SPECT). Perfusion, wall motion, transient ischaemic dilation (TID) and left ventricular (LV) ejection fraction (EF) were evaluated. None of the controls showed stress-induced abnormalities. Mental stress evoked regional changes (perfusion defects and/or wall motion abnormality) in 16 TTC subjects and global abnormalities (LVEF fall >5% and/or TID >1.10) in 13; 3 had a completely negative response. TID, delta LVEF and delta wall motion score were significantly different in TTC vs control patients: 1.08 ± 0.20 vs 0.95 ± 0.11 (p < 0.05), -1.7 ± 6% vs 4 ± 5% (p < 0.02) and 2.5 (0, 4.25) vs 0 (0, 0) (p < 0.002), respectively. Mental stress may evoke regional and/or global abnormalities in most TTC patients. The abnormal response to mental stress supports the role of sympathetic stimulation in TTC. Mental stress could thus be helpful for TTC evaluation. (orig.)

  6. Real-time axial motion detection and correction for single photon emission computed tomography using a linear prediction filter

    We have developed an algorithm for real-time detection and complete correction of the patient motion effects during single photon emission computed tomography. The algorithm is based on a linear prediction filter (LPC). The new prediction of projection data algorithm (PPDA) detects most motions-such as those of the head, legs, and hands-using comparison of the predicted and measured frame data. When the data acquisition for a specific frame is completed, the accuracy of the acquired data is evaluated by the PPDA. If patient motion is detected, the scanning procedure is stopped. After the patient rests in his or her true position, data acquisition is repeated only for the corrupted frame and the scanning procedure is continued. Various experimental data were used to validate the motion detection algorithm; on the whole, the proposed method was tested with approximately 100 test cases. The PPDA shows promising results. Using the PPDA enables us to prevent the scanner from collecting disturbed data during the scan and replaces them with motion-free data by real-time rescanning for the corrupted frames. As a result, the effects of patient motion is corrected in real time. (author)

  7. Brain single-photon emission tomography with technetium-99m hexamethylpropylene amine oxime in adolscents with intial-stage schizophrenia

    Batista, J.F. [Centro de Investigaciones Clinicas, Ciudad Habana (Cuba); Galiano, M.C. [Clinica del Adolescente, Ciudad Habana (Cuba); Torres, L.A. [Centro de Investigaciones Clinicas, Ciudad Habana (Cuba); Hernandez, M.C. [Clinica del Adolescente, Ciudad Habana (Cuba); Sosa, F. [Centro de Investigaciones Clinicas, Ciudad Habana (Cuba); Perera, A. [Centro de Investigaciones Clinicas, Ciudad Habana (Cuba); Perez, M. [Centro de Investigaciones Clinicas, Ciudad Habana (Cuba)

    1995-11-01

    The objective of this study was to search for regional cerebral blood flow (rCBF) abnormalities in adolescents with initial-stage schizophrenia by means of brain single-photon emission tomography (SPET) using technetium-99m hexamethylpropylene amine oxime (HMPAO). SPET studies were performed on a homogeneous sample of 15 carefully selected adolescents with a recent diagnosis of schizophrenia, and without previous electroconvulsive or antipsychotic drug treatment. Computed tomography (CT) and electro-encephalographic (EEG) studies were performed in all patients. Qualitative and semiquantitative analysis of {sup 99m}Tc-HMPAO SPET studies showed an impaired rCBF in 12 patients (80%). The most common pattern was a decreased uptake of {sup 99m}Tc-HMPAO in the frontal lobes, usually in the left hemisphere. Conventional and quantitative EEG was positive in 12 (80%) and 15 (100%) patients, respectively. CT findings were positive in two patients (13%). There was a high level of concordance between SPET and EEG results and between SPET and clinical features (P > 0.05). This study suggests that previously untreated patients in the first stages of schizophrenia present functional abnormalities that are revealed by brain SPET. (orig.)

  8. Clinical characteristics in patients showing ischemic electrocardiographic changes during adenosine triphosphate loading single-photon emission computed tomography

    Although ischemic electrocardiographic (ECG) changes during dipyridamole or adenosine infusion have been reported as a marker for severe coronary artery disease (CAD), few studies have focused on ST-segment changes with adenosine triphosphate (ATP)-loading myocardial single-photon emission computed tomography (SPECT). Between January 2003 and August 2008, 4650 consecutive patients underwent ATP-loading SPECT. After 1412 patients with left bundle branch block, pacemaker rhythm, or previous coronary revascularization were excluded, 16 out of 3238 patients (0.5%) showed ischemic ST-segment depression during ATP-loading myocardial SPECT. They were aged 67±11 years; 10 were men and 6 women. Of these patients, 8 demonstrated perfusion abnormalities, whereas the remaining 8 showed normal myocardial perfusion imaging. In 6 of the 8 patients with abnormal SPECT, coronary angiography was performed, revealing left main trunk disease in 1 patient, 3-vessel disease in 4, 1-vessel disease with proximal left ascending artery occlusion in 1, and an insignificant lesion in 1. By contrast, no major cardiac event was observed in the 8 patients with normal SPECT during follow-up for an average of 2 years. The prevalence of ischemic ST-segment changes during ATP loading is very rare. However, this finding should be taken into account since almost half of the patients, particularly those with perfusion abnormalities, may have severe CAD which requires coronary revascularization. (author)

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

    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.

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

    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.)

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

    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.

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

    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.

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

    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

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

    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

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

    Dawson, M.R.W. [Dept. of Psychology, Univ. of Alberta, Edmonton (Canada); Dobbs, A. [Dept. of Psychology, Univ. of Alberta, Edmonton (Canada); Hooper, H.R. [Dept. of Nuclear Medicine, Cross Cancer Inst., Edmonton, AB (Canada); McEwan, A.J.B. [Dept. of Radiology and Diagnostic Imaging, Univ. of Alberta, Edmonton (Canada); Triscott, J. [Dept. of Family Medicine and Div. of Geriatric Medicine, Univ. of Alberta, Edmonton (Canada); Cooney, J. [Dept. of Psychiatry, Univ. of Alberta, Edmonton (Canada)

    1994-12-01

    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.)

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

    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)

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

    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)

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

    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.)

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

    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.

  20. Brain single-photon emission tomography with technetium-99m hexamethylpropylene amine oxime in adolscents with intial-stage schizophrenia

    The objective of this study was to search for regional cerebral blood flow (rCBF) abnormalities in adolescents with initial-stage schizophrenia by means of brain single-photon emission tomography (SPET) using technetium-99m hexamethylpropylene amine oxime (HMPAO). SPET studies were performed on a homogeneous sample of 15 carefully selected adolescents with a recent diagnosis of schizophrenia, and without previous electroconvulsive or antipsychotic drug treatment. Computed tomography (CT) and electro-encephalographic (EEG) studies were performed in all patients. Qualitative and semiquantitative analysis of 99mTc-HMPAO SPET studies showed an impaired rCBF in 12 patients (80%). The most common pattern was a decreased uptake of 99mTc-HMPAO in the frontal lobes, usually in the left hemisphere. Conventional and quantitative EEG was positive in 12 (80%) and 15 (100%) patients, respectively. CT findings were positive in two patients (13%). There was a high level of concordance between SPET and EEG results and between SPET and clinical features (P > 0.05). This study suggests that previously untreated patients in the first stages of schizophrenia present functional abnormalities that are revealed by brain SPET. (orig.)

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

    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)

  2. Breast cancer staqging using technitium-99m sestamibi and indium-111 pentetreotide single-photon emission tomography

    We evaluated the clinical usefulness of single-photon emission tomography (SPET) with technetium-99m sestamibi and indium-111 pentetrotide in breast cancer staging. Fifteen patients with clinical and/or mammographic findings suggesting Tl-2N0-l breast cancer were studied. SPET images were acquired 20 min after 99mTc-sestamibi injection and 4 and 24 h after 111In-pentetreotide injection. Patients underwent surgery the day after the later 111In-pentetrotide acquisition. Pathological examination showed 16 tumours in the 15 patients, with one bilateral carcinoma. The mean tumour diamter was 18.7 mm. Metastatic axillary involment was found in 6/16 tumours, with a mean of five metastatic nodes per axillary node involment. Both tracers correctly identified 15/16 primary tumours and five of the six cases of metastatic axillary node involvement. No difference between the tracers was observed in breast cancer staging. 99mTc-sestamibi seems to the better tracer in terms of physical characteristics, execution time and cost-effectivness. Our data suggest the future possibility of using nuclear medicine imaging to avoid axillary dissection in patiens with Tl breast cancer

  3. Single photon emission computed tomography using N-isopropyl-p(/sup 123/I)-iodoamphetamine in spinocerebellar degeneration

    Ono, Shimato; Fukunaga, Masao; Otsuka, Nobuaki and others

    1988-05-01

    Single photon emission computed tomography (SPECT) using N-isopropyl-p-(/sup 123/I)-iodoamphetamine (/sup 123/I-IMP) was performed in 16 patients with spinocerebellar degeneration (SCD), 3 patients with other disorders and 6 normal subjects. Furthermore, 5 SCD patients and 6 normals were investigated in post-administration of 2 mg TRH, and in some of them not only early but also delayed images were obtained. The /sup 123/I-IMP activity measured in region of interest over cerebella, temporal, occipital lobes and basal ganglia was normalized to the uptake in frontal lobes. SCD, in comparison to normals, showed the decreased accumulation of /sup 123/I-IMP in cerebella, with the severity increased. Three of 5 SCD revealed the increased or unchanged ratio of cerebella to frontal lobes after TRH load, while normals did the decreased ratio. However, it was uncertain whether TRH might promote the clearance of /sup 123/I-IMP in cerebella in SCD. Thus, /sup 123/I-IMP SPECT combined with TRH load appeared to be excellent tool for study of pathophysiology in SCD.

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

    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.)

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

    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

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

    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.

  7. Single photon emission computed tomography using N-isopropyl-p[123I]-iodoamphetamine in spinocerebellar degeneration

    Single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) was performed in 16 patients with spinocerebellar degeneration (SCD), 3 patients with other disorders and 6 normal subjects. Furthermore, 5 SCD patients and 6 normals were investigated in post-administration of 2 mg TRH, and in some of them not only early but also delayed images were obtained. The 123I-IMP activity measured in region of interest over cerebella, temporal, occipital lobes and basal ganglia was normalized to the uptake in frontal lobes. SCD, in comparison to normals, showed the decreased accumulation of 123I-IMP in cerebella, with the severity increased. Three of 5 SCD revealed the increased or unchanged ratio of cerebella to frontal lobes after TRH load, while normals did the decreased ratio. However, it was uncertain whether TRH might promote the clearance of 123I-IMP in cerebella in SCD. Thus, 123I-IMP SPECT combined with TRH load appeared to be excellent tool for study of pathophysiology in SCD. (author)

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

    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

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

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

  10. Exercise-induced stunning continues for at least one hour: evaluation with quantitative gated single-photon emission tomography

    To elucidate the after-effect of exercise on left ventricular (LV) function, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were evaluated at 1 h after exercise and at rest by technetium-99m tetrofosmin gated myocardial single-photon emission tomography (SPET) using an automated program in 53 subjects. The subjects were grouped as follows: normal scan (n = 16), ischaemia (n = 19) and infarction (n = 18), based on the interpretation of perfusion images. Postexercise LVEF did not differ from resting LVEF in the groups with normal scan and infarction. In patients with ischaemia, postexercise EDV (90±17 ml, mean ±SD) and ESV (44±15 ml) were significantly higher than EDV (84±15 ml, P = 0.001) and ESV (36±14 ml, P<0.0005) at rest. LVEF was significantly depressed 1 h after exercise (53%±9% vs 58%±9%, P<0.0001). In ischaemic patients with depressed postexercise LVEF, LVEF difference between rest and postexercise showed a significant correlation with the sum of defect scores, which were reversible from exercise to rest perfusion images (r = 0.92, P<0.0001). These results indicate that exercise-induced LV dysfunction (myocardial stunning) continues for at least 1 h in ischaemic patients and that the extent of LVEF depression is determined by the severity of ischaemia. (orig.)

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

    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

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

    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)

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

    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.

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

    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.

  15. Choice of reference region in the quantification of single-photon emission tomography in primary degenerative dementia

    This study evaluated the effect of using two different reference regions in the quantification of single-photon emission tomography (SPET). SPET scans of 30 patients with Alzheimer's disease (AD) and 30 patients with frontotemporal dementia were compared with the scans of ten age-matched controls. Regions of interest (ROIs) were defined on transaxial slices by a semi-automatic method. Regional cerebral blood flow indices (rCBFi) in each ROI were determined by normalizing the count densities to both cerebellar and occipital cortex reference regions. Mean rCBFi for each ROI were calculated for the patient and control groups and significant group differences determined. The number and topographical distribution of ROIs with significant group differences varied depending upon the choice of reference region. The magnitude of these differences was greatest when the cerebellum was used as the reference region. The disparity between results obtained with the two reference regions was most apparent in the AD group. The reasons for these differences are discussed. (orig./MG)

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

    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.)

  17. Regional cerebral blood flow in patients with sickle cell disease: study with single photon emission computed tomography

    Neurological complications have been reported in patients with sickle-cell disease (SCD) using positron emission tomography (PET), magnetic resonance imaging (MRI), and computed tomography (CT), but not with single photon emission computed tomography (SPECT). The objective of this study was to investigate brain perfusion in the patients with SCD using SPECT after technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO), was administered and compare the findings with those of demography, physical examination, MRI and hematological profile. The study involved 21 patients (12 males, 9 females, age at study 8-45 years) who were known to be having SCD for a duration of at least 5 years. The patients were not in acute crisis and had normal neurological assessments with no known history of stroke or transient ischemic episode or previous abnormal CT or MRI brain scan, and were right-handed. The brain SPECT was performed after intravenous injection of 740 MBq (20 mCi) 99mTc-HMPAO in adults or an appropriate dose in pediatric patients. The scans were visually interpreted by two nuclear medicine physicians and a decision was reached by consensus. An MRI done 3 months later was interpreted by a radiologist. The demographic data and hematological profile were obtained from the medical records of the patients. Of the 21 patients, 7 (age 11-22 years) had brain perfusion deficit mostly in the frontal lobe either alone or in combination with temporal and/or parietal lobe. The MRI was abnormal in 2 patients. The brain perfusion deficit was not associated with the demographic data of the patients or hematological profiles. The findings show that SPECT was useful in detecting brain perfusion deficit in SCD patients, and such an early detection may be clinically useful in the subsequent follow-up of such patients, since it is known that cerebral perfusion deficit can lead to silent infarct and/or overt stroke, and affect cognitive skills. (author)

  18. Incorporating Quantitative Single Photon Emission Computed Tomography into Radiation Therapy Treatment Planning for Lung Cancer: Impact of Attenuation and Scatter Correction on the Single Photon Emission Computed Tomography-Weighted Mean Dose and Functional Lung Segmentation

    Purpose: To assess the impact of attenuation and scatter corrections on the calculation of single photon emission computed tomography (SPECT)-weighted mean dose (SWMD) and functional volume segmentation as applied to radiation therapy treatment planning for lung cancer. Methods and Materials: Nine patients with lung cancer underwent a SPECT lung perfusion scan. For each scan, four image sets were reconstructed using the ordered subsets expectation maximization method with attenuation and scatter corrections ranging from none to a most comprehensive combination of attenuation corrections and direct scatter modeling. Functional volumes were segmented in each reconstructed image using 10%, 20%, ..., 90% of maximum SPECT intensity as a threshold. Systematic effects of SPECT reconstruction methods on treatment planning using functional volume were studied by calculating size and spatial agreements of functional volumes, and V20 for functional volume from actual treatment plans. The SWMD was calculated for radiation beams with a variety of possible gantry angles and field sizes. Results: Functional volume segmentation is sensitive to the particular method of SPECT reconstruction used. Large variations in functional volumes, as high as >50%, were observed in SPECT images reconstructed with different attenuation/scatter corrections. However, SWMD was less sensitive to the type of scatter corrections. SWMD was consistent within 2% for all reconstructions as long as computed tomography-based attenuation correction was used. Conclusion: When using perfusion SPECT images during treatment planning optimization/evaluation, the SWMD may be the preferred figure of merit, as it is less affected by reconstruction technique, compared with threshold-based functional volume segmentation.

  19. Dual label single photon emission tomography: A new method to assess redistribution in regional coronary blood flow after nitroglycerin

    Liu, P.; Houle, S.; Kimball, B.; Burns, R.J.; Gilday, D.; Weisel, R.D.; Warbick-Cerone, A.; Johnston, L.; McLaughlin, P.R.

    1984-01-01

    The authors have developed a new method to quantitate changes in coronary blood flow (CBF) by single photon emission tomography (SPECT) of dual-labelled intracoronary human albumin microspheres (HAM) before and after an intervention. After initial validation in pigs, the authors studied 20 pts in the cath lab with 10 pts receiving saline to serve as controls, and 10 pts receiving nitroglycerin (NTG). Thermodilution coronary sinus flow (CSF) measurements were made at rest and after each intervention. After pacing to mild angina, serial injections of Tc-99m HAM, 40 ..mu..g of NTG or saline, and In-111 HAM were made in the left main coronary artery. After routine coronary arteriography, the pt underwent dual-peak SPECT with the image slices reconstructed along the longitudinal axis of the heart. Quantitative circumferential profiles were made for each slice by plotting the average count per pixel in each 18/sup 0/ segment of the left ventricle. After correction for absolute coronary blood flow, the difference between the pre- and post-NTG profile was obtained, and a significant change took place if it exceeded 2 S.D. from control. The segments were classified into normal, mildly, moderately or severely comprised territories according to upstream coronary anatomy. Results are presented. The authors conclude: (1) SPECT of intracoronary HAM combined with CSF measurement represents a powerful tool in assessing changes in regional CBF after an intervention; (2) By this method, NTG gave preferential redistribution of CBF to the mild and moderately ischemic zones of the heart.

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

    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)

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

    Introduction: This study used the dopamine transporter (DAT) probe, [123I]-2β-carbomethoxy-3β-(4-fluorophenyl)-N-(3-iodo-E-allyl)nortropane ([123I]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 [123I]altropane striatal ratios correlated with dopamine content in the striatum and substantia nigra and with behavioural outcomes. Methods: [123I]altropane images taken pre- and postlesion were acquired before and after the transplantation of neural stem/progenitor cells. The images obtained using [123I]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: [123I]altropane binding correlated with the content of dopamine in the striatum; however, [123I]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 (r2) for these correlations indicated that [123I]altropane SPECT was not a good predictor of behavioural outcomes. Conclusion: Our data reveal that [123I]altropane predicts the integrity of the striatal dopamine nerve terminals, but does not predict the integrity of the nigrostriatal system. [123I]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. The Prognostic Role of Magnetic Resonance Imaging and Single-Photon Emission Computed Tomography in Viral Encephalitis

    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

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

    We have described previously a selective serotonin transporter (SERT) radioligand, [123I]IDAM. We now report a similarly potent, but more stable IDAM derivative, 5-iodo-2-[2-[(dimethylamino)methyl]phenoxy]benzyl alcohol ([123I]ODAM). The imaging characteristics of this radioligand were studied and compared against [123I]IDAM. Dynamic sequences of single-photon emission tomography (SPET) scans were obtained on three female baboons after injection of 375 MBq of [123I]ODAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 120 min after injection of [123I]ODAM. Total integrated brain uptake of [123I]ODAM was about 30% higher than [123I]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 [123I]IDAM (1.80± 0.13). Both the binding kinetics and the metabolism of [123I]ODAM were slower than those of [123I]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 koff=0.0085±0.0028 min-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 [123I]ODAM is suitable for selective SPET imaging of SERT in the primate brain, with higher uptake and slower kinetics and metabolism than [123I]IDAM, but also a slightly lower selectivity for SERT. (orig.)

  4. Technetium-99m sestamibi and tetrofosmin myocardial single-photon emission tomography: can we use the same reference data base?

    The aim of this study was to compare technetium-99m labelled tetrofosmin and sestamibi myocardial perfusion single-photon emission tomography (SPET) with one common sestamibi reference file for bull's eye imaging, with quantitation of the extent and severity of perfusion defects. Twenty patients suspected or known to have coronary artery disease participated in the study. Patients first underwent routine sestamibi myocardial SPET over 2 days, receiving doses of 400-600 MBq at stress and 600-800 MBq at rest. Then within the same week a 1-day tetrofosmin myocardial SPET study was performed, with a dose of 300 MBq at stress, followed 2.5 h later by a dose of 750 MBq at rest. Bull's eye images were generated for visual evaluation. Black-out defects according to the Cequal software analysis were only recorded if they comprised more than 10 pixels in men and 20 in women. According to the Cequal program, extent score and severity scores were expressed as number of pixels and deviations below reference limits. Five patients had normal myocardial SPET imaging with both radiotracers, while 15 had reversible, irreversible or partially reversible defects. The concordance of the results was high. The only two significant differences were that one patient had a reversible defect which appeared to be located in different myocardial regions (LAD vs RCA), and another patient had a defect that was partially reversible with sestamibi but irreversible with tetrofosmin. The results showed very high correlation coefficients for the extent and severity scores (linear correlation coefficient values of 0.99 and 0.94, respectively). In conclusion, it appears that changing between sestamibi and tetrofosmin has little influence on the interpretation of bull's eye images from the data file of a common reference population using one of the tracers. (orig.). With 3 figs., 3 tabs

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

    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.)

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

    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.)

  7. Evaluation of single-photon emission computed tomography images obtained with and without copper filter by segmentation

    Kheruka, Subhash Chand; Aggarwal, Lalit Mohan; Sharma, Neeraj; Naithani, Umesh Chand; Maurya, Anil Kumar; Gambhir, Sanjay

    2016-01-01

    Background: Measurement of accurate attenuation of photon flux in tissue is important to obtain reconstructed images using single-photon emission computed tomography (SPECT). Computed tomography (CT) scanner provides attenuation correction data for SPECT as well as anatomic information for diagnostic purposes. Segmentation is a process of dividing an image into regions having similar properties such as gray level, color, texture, brightness, and contrast. Image segmentation is an important tool for evaluation of medical images. X-ray beam used in CT scan is poly-energetic; therefore, we have used a copper filter to remove the low energy X-rays for obtaining correct attenuation factor. Images obtained with and without filters were quantitatively evaluated by segmentation method to avoid human error. Materials and Methods: Axial images of AAPM CT phantom were acquired with 3 mm copper filter (low intensity) and without copper filter (high intensity) using low-dose CT (140 kvp and 2.5 mA) of SPECT/CT system (Hawkeye, GE Healthcare). For segmentation Simulated Annealing Based Fuzzy c-means, algorithm is applied. Quantitative measurement of quality is done based on universal image quality index. Further, for the validation of attenuation correction map of filtered CT images, Jaszczak SPECT phantom was filled with 500 MBq of 99mTc and SPECT study was acquired. Low dose CT images were acquired for attenuation correction to be used for reconstruction of SPECT images. Another set of CT images were acquired after applying additional 3 mm copper filter. Two sets of axial SPECT images were reconstructed using attenuation map from both the CT images obtained without and with a filter. Results and Conclusions: When we applied Simulated Annealing Based Fuzzy c-means segmentation on both the CT images, the CT images with filter shows remarkable improvement and all the six section of the spheres in the Jaszczak SPECT phantom were clearly visualized. PMID:27095859

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

    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. Iodine-123-labelled fatty acids for myocardial single-photon emission tomography: current status and future perspectives

    Renewed interest in the clinical use of iodine-123-labelled fatty acids is currently primarily focused on the use of iodine-123-labelled 15-(p-iodophenyl)pentadecanoic acid (IPPA) and ''modified'' fatty acid analogues such as 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) which show delayed myocardial clearance, thus permitting single-photon emission tomographic imaging. Interest in the use of BMIPP and similar agents results from the differences which have often been observed in various types of heart disease between regional myocardial uptake patterns of [123I]BMIPP and flow tracer distribution. Although the physiological basis is not completely understood, differences between regional fatty acid and flow tracer distribution may reflect alterations in important parameters of metabolism which can be useful for patient management or therapy planning. These tracers may also represent unique metabolic probes for correlation of energy substrate metabolism with regional myocardial viability. The two agents currently most widely used clinically are 123I-labelled IPPA and BMIPP. While [123I]IPPA is commercially available as a radiopharmaceutical in Europe (Cygne) and Canada (Nordion), multicenter trials are in progress in the United States as a prelude to approval for broad use. [123I]BMIPP was recently introduced as Cardiodine for commercial distribution in Japan (Nihon Medi-Physics, Inc.). [123I]BMIPP is also being used in clinical studies on an institutional approval basis at several institutions in Europe and the United States. In this review, the development of a variety of radioiodinated fatty acids is discussed. The results of clinical trials with [123I]IPPA and [123I]BMIPP are discussed in detail, as are the future prospects for fatty acid imaging. (orig.)

  10. Evaluation of acute myocardial infarction by 201Tl single-photon emission computed tomography using scoring system

    In 36 patients with acute myocardial infarction (AMI) 201Tl single photon emission computed tomography (SPECT) examinations were performed in a relatively early phase of AMI. The short and long axis views of the left ventricle (LV) were divided into 6 segments. Images of each segment were assigned scores (segmental scores) based on a visual evaluation of the extent of 201Tl accumulations. SPECT scores were compared with max GOT, max LDT, max CPK and max CK-MB, Killip classification and Forrester hemodynamic subset on admission, and LV ejection fraction (LVEF). Segmental scores were compared with LV wall motion evaluated by left ventriculography. The results are as follows: There were significant correlations between SPECT scores and max GOT, max LDH, max CPK and max CK-MB. SPECT scores in patients with Killip group III were significantly higher than in patients with Killip group I+II. However, no significant differences in max GOT, max LDH, max CPK and max CK-MB were observed between patients with Killip group III and those with Killip group I+II. SPECT scores were significantly higher in patients with Forrester group III+IV than in patients with Forrester group I+II. Segmental scores in segments evaluated as akinesis, dyskinesis and aneurysm by left ventriculography were significantly higher than those evaluated as hypokinesis or normal. Segmental scores in segments evaluated as hypokinesis were significantly high in comparison with normal segments. Significant correlations were observed between LVEF and SPECT scores. However, LVEF correlated poorly with max GOT, max LDH and max CPK, and no significant correlation was observed between LVEF and max CK-MB. SPECT examinations were performed in 11 patients in both the acute and chronic phase of AMI. SPECT scores in the chronic phase did not change in 4 patients, decreased in 5, increased in 2. These results suggest that SPECT scores and segmental scores can be useful indices in the evaluation of AMI. (J.P.N.)

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

    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.)

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

    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 evaluated for application to cerebral perfusion SPET imaging in ischaemic stroke. It has been shown that useful quantitative estimates, high sensitivity and high specificity may be obtained. Sensitivity and the accuracy of signal quantification were found to be dependent on the operator defined analysis parameters. Recommendations for the values of these parameters have been made. The analysis method developed has been compared with an established method and shown to result in higher specificity for the data and analysis parameter sets tested. In addition, application to a group of ischaemic stroke patient SPET scans has demonstrated its clinical utility. The influence of imaging conditions has been assessed using phantom data acquired with different gamma camera SPET acquisition parameters. A lower limit of five million counts and standardisation of all acquisition parameters has been recommended for the analysis of individual SPET scans. (author)

  13. Feasibility and value of fully 3D Monte Carlo reconstruction in single-photon emission computed tomography

    The accuracy of Single-Photon Emission Computed Tomography images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using four methods: filtered backprojection, MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20-70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation

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

    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

  15. Non-ossifying fibroma mimicking distant metastasis of osteosarcoma on 99mTc-methylene diphosphonate bone scintigraphy: Diagnosis with single photon emission tomography/computed tomography

    Non-ossifying fibromas (NOFs) are benign bone lesions with variable appearance on bone scintigraphy. Single photon emission tomography/computed tomography (SPECT/CT) can help in accurate characterization of these lesions. We present a case of 14-year-old boy with recurrent osteosarcoma where NOF was mimicking distant metastasis on 99mTc-methylene diphosphonate bone scintigraphy. SPECT/CT was able to correctly characterize the lesion as NOF, thereby altering the management

  16. Zolpidem-Induced Arousal by Paradoxical GABAergic Stimulation: A Case Report With F-18 Flumazenil Positron Emission Tomography and Single Photon Emission Computed Tomography Study

    Kim, Changjae; Nam, Ki Yeun; Park, Jin Woo; Lee, Ho Jun

    2016-01-01

    Zolpidem is a non-benzodiazepine drug that has selectivity for the gamma-aminobutyric acid (GABA) receptors. We experienced paradoxical effect of zolpidem in a 48-year-old male patient with hypoxic-ischemic brain injury after cardiac arrest. The patient was in stupor and could not communicate. His Glasgow Coma Scale (GCS) was E2M4V2 and Rancho Los Amigos (RLA) was grade III to IV. Zolpidem was prescribed to induce sedation but paradoxically, he became alert (GCS 15, RLA VII) and was able to communicate. The arousal lasted for 2 hours repeatedly following each administration of the medication. While he was alert, electroencephalogram showed the reversal of slow wave into beta range fast activity and F-18 flumazenil positron emission tomography (PET) showed increased GABAergic receptor activity in both frontoparietotemporal cortices. Single photon emission computed tomography (SPECT) also showed increased cerebral perfusion and reversal of cerebellar diaschisis. PMID:26949686

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

    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

  18. Comparison of single photon emission computed tomography-computed tomography, computed tomography, single photon emission computed tomography and planar scintigraphy for characterization of isolated skull lesions seen on bone scintigraphy in cancer patients

    The purpose of this study is to evaluate the added value of single photon emission computed tomography-computed tomography (SPECT-CT) over planar scintigraphy, SPECT and CT alone for characterization of isolated skull lesions in bone scintigraphy (BS) in cancer patients. A total of 32 cancer patients (age: 39.5 ± 21.9; male: female - 1:1) with 36 isolated skull lesions on planar BS, underwent SPECT-CT of skull. Planar BS, SPECT, CT and SPECT-CT images were evaluated in separate sessions to minimize recall bias. A scoring scale of 1-5 was used, where 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. With receiver operating characteristic analysis area under the curves (AUC) was calculated for each modality. For calculation of sensitivity, specificity and predictive values a Score ≤3 was taken as metastatic. Clinical/imaging follow-up and/or histopathology were taken as reference standard. Of 36 skull lesions 11 lesions each were on frontal, parietal and occipital bone while three lesions were in the temporal bone. Of these 36 lesions, 16 were indeterminate (Score-3) on planar and SPECT, five on CT and none on SPECT-CT. The AUC was largest for SPECT-CT followed by CT, SPECT and planar scintigraphy, respectively. Planar scintigraphy was inferior to SPECT-CT (P = 0.006) and CT (P = 0.012) but not SPECT (P = 0.975). SPECT was also inferior to SPECT-CT (P = 0.007) and CT (P = 0.015). Although no significant difference was found between SPECT-CT and CT (P = 0.469), the former was more specific (100% vs. 94%). SPECT-CT is better than planar scintigraphy and SPECT alone for correctly characterizing isolated skull lesions on BS in cancer patients. It is more specific than CT, but provides no significant advantage over CT alone for this purpose

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

    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.)

  20. Investigations of photon emission from plants exposed to UV-C-radiation and ozone by means of a portable single photon counter

    Photon emission is inherently associated with fundamental biological processes such as cell division, photosynthesis, stress or death of organisms. In green plants photon emission originates in chloroplasts. For demonstrating the potential use of photon emission for monitoring stress effects on plants I designed a portable single photon counter based on a red-sensitive photomultiplier with a suitable characteristic. The single photon counter is a cylindric detector unit fitted in a light-tight measuring chamber. The measuring signal is recorded with a counter device plugged in a laptop. Several plants (duckweed spirodela polyrhiza, winter wheat Triticum aestivum L. cv. Perlo and poplar Populus nigra) were analyzed for photon emission after light excitation (photoluminescence) and spontaneous emission (ultraweak photon emission or luminescence). The results show that photon emission of green plants acts as an indicator of UV-C and ozone stress response. Both photoluminescence and spontaneous luminescence were significantly changed in plants exposed to UV-C radiation (3 mW/m2 for 10-40 min) and ozone (440 ppb for 2 h and 80 ppb 8 h a day for several weeks) as compared to the control. Thus the new portable photon counter can be used successfully for detailed and sensitive in situ investigations of photon emission from stressed plants. This analytical method may complement other techniques used in plant physiology, especially those for studying effects on photosynthesis. (author)

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

    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.

  2. Limited performance of quantitative assessment of myocardial function by thallium-201 gated myocardial single-photon emission tomography

    We investigated the reproducibility between thallium-201 and technetium-99m methoxyisobutylisonitrile (MIBI) gated single-photon emission tomography (SPET) for the assessment of indices of myocardial function such as end-diastolic and end-systolic volume (EDV, ESV), ejection fraction (EF) and wall motion. Rest 201Tl (111 MBq) gated SPET was sequentially performed twice in 20 patients. Rest 201Tl gated SPET and rest 99mTc-MIBI (370 MBq) gated SPET were performed 24 h apart in 40 patients. Wall motion was graded using the surface display of the Cedars quantitative gated SPET (QGS) software. EDV, ESV and EF were also measured using the QGS software. The reproducibility of functional assessment on rest 201Tl gated SPET was compared with that on 99mTc-MIBI gated SPET, and also with that between 201Tl gated SPET and 99mTc-MIBI gated SPET performed on the next day. The two standard deviation (2 SD) values for EDV, ESV and EF on the Bland-Altman plot were 29 ml, 19 ml and 12%, respectively, on repeated 201Tl gated SPET, compared with 14 ml, 11 ml and 5.3% on repeated 99mTc-MIBI gated SPET. The correlations were good (r=0.96, 0.97 and 0.87) between the two measurements of EDV, ESV and EF on repeated rest studies with 201Tl and 99mTc-MIBI gated SPET. However, Bland-Altman analysis revealed that the 2 SD values between the two measurements were 31 ml, 23 ml and 12%. We were able to score the wall motion in all cases using the 3D surface display of the QGS on 201Tl gated SPET. The kappa value of the wall motion grade on the repeated 201Tl study was 0.35, while that of the wall motion grade on the repeated 99mTc-MIBI study was 0.76. The kappa value was 0.49 for grading of wall motion on repeated rest studies with 201Tl and 99mTc-MIBI. In conclusion, QGS helped determine EDV, ESV, EF and wall motion on 201Tl gated SPET. Because the EDV, ESV and EF were less reproducible on repeated 201Tl gated SPET or on 201Tl gated SPET and 99mTc-MIBI gated SPET on the next day than on repeated

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

    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

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

    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

  5. The value of quantitative gallium-67 single-photon emission tomography in the clinical management of malignant external otitis

    The objective of this study was to establish whether quantitative gallium-67 single-photon emission tomography (SPET) represents an accurate method for the assessment of infection and, moreover, for the monitoring of therapeutic effect. Eight patients (five males, three females) with the clinical diagnosis of MEO were studied. In three patients antibiotic treatment was prolonged for several weeks because visual analysis of gallium scintigraphy still showed slightly increased uptake in the affected area on the first follow-up scan. In one patient, it was decided to stop antibiotic treatment despite a slight increase in uptake on the second follow-up scan. Lesion to non-lesion (L/NL) ratios obtained from 67Ga SPET images at initial diagnosis and during follow-up were assessed in correlation with clinical and biochemical data and with the results of CT scans. In addition to a raised erythrocyte sedimentation rate (ESR), all patients showed increased uptake on the affected side, with L/NL ratios ranging from 1.4 to 3.6 at the time of diagnosis. CT scans failed to demonstrate abnormalities in four patients. Including four scans demonstrating slightly increased uptake in the affected area, L/NL ratios after 6-8 weeks of antibiotic treatment were 1.0±0.1. Despite a persistently elevated ESR in the majority of patients, none of them demonstrated local recurrence or complications during follow-up. In all patients, leucocyte count was within the normal range throughout the course. No relation was found between the slightly increased uptake on the follow-up scans and surgical treatment. It is concluded that in addition to the visual analysis of 67Ga SPET imaging, L/NL ratios should be calculated for a more accurate assessment of disease activity in MEO. Despite visually slightly increased uptake, L/NL ratios of 1.0±0.1 during follow-up are highly indicative of complete recovery, regardless of ESR values or leucocytosis. CT scans are of little value for diagnosis or for

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

    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.

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

    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.

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

    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

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

    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.

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

    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