Science.gov

Sample records for single-photon emission computerized

  1. SPECT (Single-Photon Emission Computerized Tomography) Scan

    MedlinePlus

    SPECT scan Overview By Mayo Clinic Staff A single-photon emission computerized tomography (SPECT) scan lets your doctor analyze the function of some of your internal organs. A SPECT scan is a type of nuclear imaging test, ...

  2. Single photon emission computerized tomography (SPECT) in detecting neurodegeneration in Huntington's disease.

    PubMed

    Reynolds, N C; Hellman, R S; Tikofsky, R S; Prost, R W; Mark, L P; Elejalde, B R; Lebel, R; Hamsher, K S; Swanson, S; Benezra, E E

    2002-01-01

    Single photon emission computerized tomography (SPECT) studies were performed on 34 manifest Huntington's disease (HD) patients at various stages of clinical pathology ranging from early chorea to late dystonia with or without signs of dementia and 12 pre-symptomatic patients with abnormal terminal CAG expansions. Thirty HD patients with obvious clinical signs and seven pre-symptomatic patients without signs or symptoms of HD displayed selective caudate hypoperfusion by direct visual inspection. Such qualitative, selective striatal hypoperfusion patterns can be indicative of early and persistent metabolic changes in striatal neuropathology. SPECT studies can be useful in documenting early pre-clinical changes in patients with abnormal terminal CAG expansions and in confirming the presence of caudate pathology in patients with clinical signs of HD.

  3. Definition of hepatic tumor microcirculation by Single Photon Emission Computerized Tomography (SPECT)

    SciTech Connect

    Gyves, J.W.; Ziessman, H.A.; Ensminger, W.D.; Thrall, J.H.; Niederhuber, J.E.; Keyes, J.W. Jr.; Walker, S.

    1984-09-01

    Single photon emission computerized tomography coupled with Tc-99m MAA hepatic-arterial perfusion scintigraphy has been used to examine the density of the functional microcirculation of hepatic tumors relative to normal liver in 24 patients. In both colorectal and carcinoid tumors the authors have demonstrated an average three-fold greater arteriolar-capillary density in areas of tumor proliferation. The depth of the evoked tumor hypervascularity was found to extend about 4 cm. Tumors greater than 8-9 cm in diameter were uniformly found to have a central hypovascular core. These observations are of importance in the design of selective strategies utilizing therapeutic microspheres directed against the hypervascular proliferating regions of human tumors.

  4. Central representation of phantom limb phenomenon in amputees studied with single photon emission computerized tomography.

    PubMed

    Liaw, M Y; You, D L; Cheng, P T; Kao, P F; Wong, A M

    1998-01-01

    To explore the possible mechanisms of phantom limb discomfort after amputation, three amputees with phantom limb pain were studied. This study examined the change of regional cerebral blood flow using technetium-99m hexamethylpropyleneamine oxime-single photon emission computerized tomography, which was arranged at the time of severe phantom limb discomfort and after the discomfort subsided or was completely relieved. Nine representative transverse slices parallel to the orbitomeatal line were selected for quantification. The cortical ribbon (2-cm thickness) was equally subdivided into 12 symmetrical pairs of sector regions of interest in each slice. The irregularly shaped regions of interest were drawn manually around the right thalamus and basal ganglion and then mirrored to the left thalamus and basal ganglion. The contralateral to ipsilateral ratio of regional cerebral blood flow for each area was calculated. The intensity of phantom limb pain was evaluated on a 0 to 10 visual analog scale. In Cases 1 and 2, the contralateral to ipsilateral regional cerebral blood flow ratios of multiple areas of the frontal, temporal, or parietal lobes were increased at the time of more severe phantom limb pain, and the ratios were normalized or even decreased when the phantom limb pain subsided. In Case 3, increased contralateral to ipsilateral regional cerebral blood flow ratios were also found over the frontal, temporal, and parietal lobe. However, most of the increased regional cerebral blood flow ratios of regions of interest in the first study persisted in the follow-up study. Also, the regional cerebral blood flow ratios of greater number of regions of interest of the same gyrus and new gyrus were increased. There was no significant right-left difference of regional cerebral blood flow over bilateral thalami and basal ganglia in all three cases. The results suggested that phantom limb pain might be associated with cortical activation involving the frontal, temporal, or

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

    PubMed Central

    Harisankar, Chidambaram Natrajan Balasubramanian; Mittal, Bhagwant Rai; Bhattacharya, Anish; Kashyap, Raghava; Bhansali, Anil

    2012-01-01

    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. PMID:23599604

  6. Evaluation of the effects of functional orthopaedic treatment on temporomandibular joints with single-photon emission computerized tomography.

    PubMed

    Güner, D D; Oztürk, Y; Sayman, H B

    2003-02-01

    The aims of this investigation were to evaluate the temporomandibular joints (TMJs) with single-photon emission computerized tomography (SPECT) in subjects treated with a mandibular advancement repositioning splint (MARS), and to compare the results with the total effect on dento-facial morphology. The study was undertaken on 17 Class II division 1 malocclusion subjects (nine males, eight females) with mandibular retrusion. Ten patients (five males, five females) formed the treatment group and seven (four males, three females) were used as the control. SPECT was performed only in the treatment group. Cephalometric evaluation showed significant increases in NAPog (P < 0.001) and SNB (P < 0.05) angles. Increased bone formation in theTMJs was analysed with the aid of pre- and post-treatment scintigraphic studies. The results indicate that new bone formation in the mandibular condyles seems to contribute to the increase in mandibular prognathism resulting from functional jaw orthopaedics.

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

    PubMed Central

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

    2014-01-01

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

  8. A novel three-dimensional image reconstruction method for near-field coded aperture single photon emission computerized tomography

    PubMed Central

    Mu, Zhiping; Hong, Baoming; Li, Shimin; Liu, Yi-Hwa

    2009-01-01

    Coded aperture imaging for two-dimensional (2D) planar objects has been investigated extensively in the past, whereas little success has been achieved in imaging 3D objects using this technique. In this article, the authors present a novel method of 3D single photon emission computerized tomography (SPECT) reconstruction for near-field coded aperture imaging. Multiangular coded aperture projections are acquired and a stack of 2D images is reconstructed separately from each of the projections. Secondary projections are subsequently generated from the reconstructed image stacks based on the geometry of parallel-hole collimation and the variable magnification of near-field coded aperture imaging. Sinograms of cross-sectional slices of 3D objects are assembled from the secondary projections, and the ordered subset expectation and maximization algorithm is employed to reconstruct the cross-sectional image slices from the sinograms. Experiments were conducted using a customized capillary tube phantom and a micro hot rod phantom. Imaged at approximately 50 cm from the detector, hot rods in the phantom with diameters as small as 2.4 mm could be discerned in the reconstructed SPECT images. These results have demonstrated the feasibility of the authors’ 3D coded aperture image reconstruction algorithm for SPECT, representing an important step in their effort to develop a high sensitivity and high resolution SPECT imaging system. PMID:19544769

  9. Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study.

    PubMed

    Van de Kelft, Erik; Verleye, Gino; Van de Kelft, An-Sofie; Melis, Koen; Van Goethem, Johan

    2017-10-01

    The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP. To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II). A prospective comparative study. Two hundred patients were enrolled: 96 in Group I and 104 in Group II. Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records. Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest. The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this

  10. Crossed cerebellar diaschisis in ischemic stroke: a study of regional cerebral blood flow by /sup 133/Xe inhalation and single photon emission computerized tomography

    SciTech Connect

    Meneghetti, G.; Vorstrup, S.; Mickey, B.; Lindewald, H.; Lassen, N.A.

    1984-06-01

    Seventy measurements of CBF were performed in 12 stroke patients by /sup 133/Xe inhalation and a rapidly rotating single photon emission computerized tomograph. CBF was measured every other day during the acute phase and at 2- and 6-month follow-up visits. A persistent contralateral cerebellar blood flow depression was evident in five patients with severe hemispheric low flow areas, which correlated with large, hypodense lesions on the computerized tomographic scan. In a sixth patient with a small, deep infarct, a transient crossed cerebellar low flow was observed, while the clinical symptoms persisted. It is concluded from this serial study that crossed cerebellar diaschisis is a common finding in completed stroke. It is probably caused by disconnection of the corticopontine pathways, a disconnection that tends to persist. The phenomenon is in fact less variable than the stroke-related CBF changes in the infarcted hemisphere, in which a period of relative hyperemia is frequently seen.

  11. Single photon emission computerized tomography and histological evaluation in the validation of a new technique for closure of oro-antral communication: an experimental study in pigs.

    PubMed

    Ogunsalu, C O; Rohrer, M; Persad, Hari; Archibald, A; Watkins, J; Daisley, H; Ezeokoli, C; Adogwa, A; Legall, C; Khan, O

    2008-03-01

    Various bone regeneration techniques have evolved recently but controversies regarding vascularization and integration of such bone grafting techniques have led occasionally to animal experiment to validate such techniques. The objective of this study was to evaluate the evidence of vascularization and osseo-integration of a new bone regeneration technique utilized for the closure of oro-antral communication (OAC) by an experimental model in which Single Photon Emission computerized Tomography and histological studies were conducted in pigs. We conclude that the sandwich technique used for the closure of OAC results in a vascularized new bone formation which eventually osseo-integrate with the surrounding bone. Also, this experimental study confirmed that autogeneous bone graft was superior to xenografts when used within the sandwich unit.

  12. Single photon emission computed tomography

    SciTech Connect

    Piez, C.W. Jr.; Holman, B.L.

    1985-07-01

    Single photon emission computed tomography (SPECT) is becoming an increasingly important part of routine clinical nuclear medicine. By providing tomographic reconstructions in multiple planes through the patient, SPECT expands the clinical applications in nuclear medicine as well as providing better contrast, edge definition and separation of target from background activities. Imaging techniques have been developed for the evaluation of regional cerebral blood flow using radiolabeled amines. Thus, cerebral functional imaging can be used in the diagnosis of acute cerebral infarction, cerebral vascular disease, dementia and epilepsy. SPECT plays a complementary role in the evaluation of coronary artery disease, particularly when it is coupled with thallium-201 and exercise testing. SPECT extends our diagnostic capabilities in additional areas, such as liver and bone scintigraphy as well as tumor imaging with gallium-67.

  13. A Family with Von Hippel-Lindau Syndrome: The Findings of Indium-111 Somatostatin Receptor Scintigraphy, Iodine-123 Metaiodobenzylguanidine Scintigraphy and Single Photon Emission Computerized Tomography

    PubMed Central

    Arıcan, Pelin; Okudan Tekin, Berna; Naldöken, Seniha; Şefizade, Rıza; Berker, Dilek

    2017-01-01

    Von Hippel-Lindau syndrome (VHLS) is an autosomal dominant hereditary familial disorder characterized by development of malignant and benign neoplasms. Differential diagnosis of the adrenal and pancreatic masses are difficult in patients with VHLS. Iodine-123 metaiodobenzylguanidine (I-123 MIBG) and indium-111 somatostatin receptor scintigraphies (In-111 SRS) have important roles in the differential diagnosis of adrenal and pancreatic masses in those patients. In this case report, we present the findings of I-123 MIBG single-photon emission computerized tomography (SPECT/CT) and In-111 SRS SPECT/CT in three members of a family with VHLS. In case 1, a residual neuroendocrine tumor (NET) was detected in the head of pancreas on In-111 SRS SPECT/CT images. In case 2 and 3, I-123 MIBG SPECT/CT confirmed the adrenal masses as pheochromocytoma, and the extra-adrenal mass as NET, before surgery. We thought that In-111 SRS and I-123 MIBG scan might be helpful in the routine work up of VHLS patients for diagnostic and therapeutic purposes. Hybrid SPECT/CT system may improve diagnostic accuracy of planar images since it assesses morphologic and functional information together. PMID:28291009

  14. Clinical significance of right ventricular activity on treadmill thallium-201 myocardial single-photon emission computerized tomography using cadmium-zinc-telluride cameras.

    PubMed

    Ko, Kuan-Yin; Wu, Yen-Wen; Liu, Chia-Ju; Cheng, Mei-Fang; Yen, Ruoh-Fang; Tzen, Kai-Yuan

    2016-06-01

    Identification of right ventricular (RV) abnormalities is important in patients with suspected coronary artery disease (CAD). RV activity can be better visualized on myocardial single-photon emission computerized tomography (SPECT) using a higher sensitivity cadmium-zinc-telluride (CZT) detector. The aim of this study was to investigate the clinical significance of RV/left ventricular (LV) uptake ratios during exercise thallium-201 SPECT using CZT detectors. A total of 102 patients underwent treadmill ECG-gated SPECT, coronary angiography, and echocardiography. SPECT myocardial perfusion was interpreted using a 17-segment model and a 0-4-point scale. RV/LV uptake ratios were calculated on the basis of maximum counts per pixel within the entire RV and LV walls. The relationships between RV/LV uptake ratio and gated SPECT, presence of CAD (≥50% stenosis in the left main or ≥70% in the main branches), demographics, and echocardiographic parameters were analyzed. Stress RV/LV ratios correlated positively with the presence of left main or multivessel disease, and tricuspid regurgitation maximum pressure gradient. After multivariate regression, stress/rest RV/LV ratios correlated positively with mitral flow deceleration time, age, female sex, and use of β-blockers. RV/LV uptake ratios on the basis of exercise myocardial perfusion SPECT imaging using CZT cameras are useful for the detection of severe CAD and could serve as an indicator of pulmonary hypertension and LV diastolic dysfunction.

  15. Technetium-99m dimercaptosuccinic acid scan in evaluation of renal cortical scarring: Is it mandatory to do single photon emission computerized tomography?

    PubMed Central

    Saleh Farghaly, Hussein Rabie; Mohamed Sayed, Mohamed Hosny

    2015-01-01

    Objectives: Renal cortical scintigraphy with technetium-99m (Tc-99m) dimercaptosuccinic acid (DMSA) is the method of choice to detect acute pyelonephritis and cortical scarring. Different acquisition methods have been used: Planar parallel-hole or pinhole collimation and single photon emission tomography (SPECT). This study compared planar parallel-hole cortical scintigraphy and dual-head SPECT for detection of cortical defects. Patients and Methods: We retrospectively reviewed 190 consecutive patients with 380 kidneys and 200 DMSA scans referred to rule out renal cortical scarring. The diagnoses were 52 vesicoureteric reflux, 61 recurrent urinary tract infection, 39 hydronephrosis, 20 renal impairment, and 18 hypertension. All patients were imaged 3 h after injection of Tc-99m DMSA with SPECT and planar imaging (posterior, anterior, left, and right posterior oblique views). For each patient, planar and SPECT images were evaluated at different sittings, in random order. Each kidney was divided into three cortical segments (upper, middle and lower) and was scored as normal or reduced uptake. The linear correlation coefficient for the number of abnormal segments detected between planner and SPECT techniques was calculated. Results: From 200 DMSA scans, 100 scans were positive for scar in SPECT images, from which only 95 scans were positive for scar in planner imaging. Out of the five mismatched scans, three scans were for patients with renal impairment and high background activity and two scans were for very small scars. No significant difference was seen in the average number of abnormal segments detected by planar versus SPECT imaging (P = 0.31). The average correlation coefficient between was high (r = 0.91 – 0.92). Conclusions: Tc-99m DMSA renal cortical scanning using SPECT offers no statistically significant diagnostic advantage over multiple views planar imaging for detection of cortical defect. PMID:25589802

  16. Single photon emission based on coherent state preparation

    NASA Astrophysics Data System (ADS)

    Ester, P.; Lackmann, L.; Michaelis de Vasconcellos, S.; Hübner, M. C.; Zrenner, A.; Bichler, M.

    2007-09-01

    The authors report here on deterministic single photon emission after coherent optical state preparation in the p-shell of a single InGaAs /GaAs quantum dot. In the approach, they use p-shell Rabi flopping followed by relaxation to the s-shell ground state with subsequent spontaneous single photon emission. Pulsed photon correlation experiments show complete suppression of the correlation peak at zero time delay and hence demonstrate clean single photon emission.

  17. High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease)

    SciTech Connect

    De Chiara, S.; Lassen, N.A.; Andersen, A.R.; Gade, A.; Lester, J.; Thomsen, C.; Henriksen, O.

    1987-01-01

    Pure sensory stroke (PSS) is typically caused by a lacunar infarct located in the ventral-posterior (VP) thalamic nucleus contralateral to the paresthetic symptoms. The lesion is usually so small that it cannot be seen on computerized tomography (CT), as illustrated by our case. In our moderately hypertensive, 72-year-old patient with PSS, CT scanning and conventional nuclear magnetic resonance imaging (NMRI) scanning using a 7-mm-thick slice on a 1.5 Tesla instrument all failed to visualize the thalamic infarct. Using the high-resolution mode with 2-mm slice thickness it was, however, clearly seen. In addition, NMRI unexpectedly showed diffuse periventricular demyelinization as well as three other lacunar infarcts, i.e., findings characteristic of subcortical arteriosclerotic encephalopathy (SAE). This prompted psychometric testing, which revealed signs of mild (subclinical) dementia, in particular involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric distribution of cerebral blood flow (CBF), with an 18% lower value in the right parietal cortex compared to the left side; this indicated asymmetric disconnection of the cortex by the SAE. Thus, the tomograms of the functional parameter, CBF, correlated better with the deficits revealed by neuropsychological testing than by CT or NMRI.

  18. Single photon emission computed tomography (SPECT) in epilepsy

    SciTech Connect

    Leroy, R.F.

    1991-12-31

    Epilepsy is a common neurologic disorder which has just begun to be studied with single photon emission computerized tomography (SPECT). Epilepsy usually is studied with electroencephalographic (EEG) techniques that demonstrate the physiologic changes that occur during seizures, and with neuroimaging techniques that show the brain structures where seizures originate. Neither method alone has been adequate to describe the pathophysiology of the patient with epilepsy. EEG techniques lack anatomic sensitivity, and there are no structural abnormalities shown by neuroimaging which are specific for epilepsy. Functional imaging (FI) has developed as a physiologic tool with anatomic sensitivity, and SPECT has been promoted as a FI technique because of its potentially wide availability. However, SPECT is early in its development and its clinical utility for epilepsy still has to be demonstrated. To understand this role of SPECT, consideration must be given to the pathophysiology of epilepsy, brain physiology, types of seizure, epileptic syndromes, and the SPECT technique itself. 44 refs., 2 tabs.

  19. Single photon emission computed tomography in AIDS dementia complex

    SciTech Connect

    Pohl, P.; Vogl, G.; Fill, H.; Roessler, H.Z.; Zangerle, R.; Gerstenbrand, F.

    1988-08-01

    Single photon emission computed tomography (SPECT) studies were performed in AIDS dementia complex using IMP in 12 patients (and HM-PAO in four of these same patients). In all patients, SPECT revealed either multiple or focal uptake defects, the latter corresponding with focal signs or symptoms in all but one case. Computerized tomography showed a diffuse cerebral atrophy in eight of 12 patients, magnetic resonance imaging exhibited changes like atrophy and/or leukoencephalopathy in two of five cases. Our data indicate that both disturbance of cerebral amine metabolism and alteration of local perfusion share in the pathogenesis of AIDS dementia complex. SPECT is an important aid in the diagnosis of AIDS dementia complex and contributes to the understanding of the pathophysiological mechanisms of this disorder.

  20. Single-photon emission computed tomography (SPECT): Applications and potential

    SciTech Connect

    Holman, B.L.; Tumeh, S.S. )

    1990-01-26

    Single-photon emission computed tomography has received increasing attention as radiopharmaceuticals that reflect perfusion, metabolism, and receptor and cellular function have become widely available. Perfusion single-photon emission computed tomography of the brain provides functional information useful for the diagnosis and management of stroke, dementia, and epilepsy. Single-photon emission computed tomography has been applied to myocardial, skeletal, hepatic, and tumor scintigraphy, resulting in increased diagnostic accuracy over planar imaging because background activity and overlapping tissues interfere far less with activity from the target structure when tomographic techniques are used. Single-photon emission computed tomography is substantially less expensive and far more accessible than positron emission tomography and will become an increasingly attractive alternative for transferring the positron emission tomography technology to routine clinical use.

  1. Single photon emission from ZnO nanoparticles

    SciTech Connect

    Choi, Sumin; Ton-That, Cuong; Phillips, Matthew R.; Aharonovich, Igor; Johnson, Brett C.; Castelletto, Stefania

    2014-06-30

    Room temperature single photon emitters are very important resources for photonics and emerging quantum technologies. In this work, we study single photon emission from defect centers in 20 nm zinc oxide (ZnO) nanoparticles. The emitters exhibit bright broadband fluorescence in the red spectral range centered at 640 nm with polarized excitation and emission. The studied emitters showed continuous blinking; however, bleaching can be suppressed using a polymethyl methacrylate coating. Furthermore, hydrogen termination increased the density of single photon emitters. Our results will contribute to the identification of quantum systems in ZnO.

  2. Diagnosis of dementia with single photon emission computed tomography

    SciTech Connect

    Jagust, W.J.; Budinger, T.F.; Reed, B.R.

    1987-03-01

    Single photon emission computed tomography is a practical modality for the study of physiologic cerebral activity in vivo. We utilized single photon emission computed tomography and N-isopropyl-p-iodoamphetamine iodine 123 to evaluate regional cerebral blood flow in nine patients with Alzheimer's disease (AD), five healthy elderly control subjects, and two patients with multi-infarct dementia. We found that all subjects with AD demonstrated flow deficits in temporoparietal cortex bilaterally, and that the ratio of activity in bilateral temporoparietal cortex to activity in the whole slice allowed the differentiation of all patients with AD from both the controls and from the patients with multi-infarct dementia. Furthermore, this ratio showed a strong correlation with disease severity in the AD group. Single photon emission computed tomography appears to be useful in the differential diagnosis of dementia and reflects clinical features of the disease.

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

    PubMed

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

    2015-12-01

    Chronotropic incompetence, measured by the percentage (%) of heart rate (HR) reserve achieved (%HR reserve), abnormal HR recovery, reduced exercise capacity (EC), and myocardial perfusion single-photon emission computerized tomography (SPECT MPS) abnormalities are known predictors of all-cause mortality (ACM) and cardiac death (CD). The aim of this study was to determine if EC, %HR reserve, and HR recovery add incremental value to MPS in the prediction of ACM and CD. A total of 11,218 patients without valvular disease and not on β blockers underwent symptom-limited exercise MPS. %HR reserve was (peak HR - rest HR)/(220 - age - rest HR) × 100, with %HR reserve <80 defined as low. HR recovery was peak HR - recovery HR. An HR recovery <22 beats/min at 2 minutes after peak exercise was considered abnormal. Poor EC was defined as exercise duration ≤6 minutes (7 metabolic equivalents). Summed stress scores (SSSs) were calculated using a 20-segment, 5-point MPS model. Statistical analysis was performed using Cox regression models. There were 445 deaths (148 CD) during a mean follow-up of 3.2 ± 2.5 years. In multivariate analysis, the independent predictors of ACM were age, χ(2) = 154.81; EC, χ(2) = 74.00; SSS, χ(2) = 32.99; %HR reserve, χ(2) = 24.74; abnormal electrocardiogram at rest, χ(2) = 23.13; HR recovery, χ(2) = 18.45; diabetes, χ(2) = 17.75; and previous coronary artery disease, χ(2) = 11.85 (p ≤0.0006). The independent predictors of CD were SSS, χ(2) = 54.25; EC, χ(2) = 49.34; age, χ(2) = 46.45; abnormal electrocardiogram at rest, χ(2) = 30.60; previous coronary artery disease, χ(2) = 20.69; Duke treadmill score, χ(2) = 19.50; %HR reserve, χ(2) = 11.43; diabetes, χ(2) = 10.23 (all p ≤0.0014); and HR recovery, χ(2) = 5.30 (p = 0.0214). The exercise variables showed increases in Harrell's C static and net improvement reclassification, with EC showing the strongest incremental improvement in predicting ACM and CD (respective C-index 76

  4. Single photon emission computed tomography in seizure disorders.

    PubMed Central

    Denays, R; Rubinstein, M; Ham, H; Piepsz, A; Noël, P

    1988-01-01

    Fourteen children with various seizure disorders were studied using a cerebral blood flow tracer, 123I iodoamphetamine (0.05 mCi/kg), and single photon emission computed tomography (SPECT). In the five patients with radiological lesions, SPECT showed congruent or more extensive abnormalities. Five of the nine children with a normal scan on computed tomography had abnormal SPECT studies consisting of focal hypoperfusion, diffuse hemispheric hypoperfusion, multifocal and bilateral hypoperfusion, or focal hyperperfusion. A focal lesion seen on SPECT has been found in children with tonic-clonic seizures suggesting secondarily generalised seizures. Moreover the pattern seen on SPECT seemed to be related to the clinical status. An extensive impairment found on SPECT was associated with a poor evolution in terms of intellectual performance and seizure frequency. Conversely all children with a normal result on SPECT had less than two seizures per year and normal neurological and intellectual development. Images Figure PMID:3264135

  5. The investigation of Alzheimer's disease with single photon emission tomography.

    PubMed Central

    Burns, A; Philpot, M P; Costa, D C; Ell, P J; Levy, R

    1989-01-01

    Twenty patients satisfying standard clinical criteria for Alzheimer's disease (AD) and six age-matched normal controls were studied using 99mTc hexamethyl-propyleneamine oxime and single photon emission tomography. The AD patients had lower regional cerebral blood flow (rCBF) in the temporal and posterior parietal lobes compared to controls. AD patients with apraxia and aphasia had lower rCBF in the lateral temporal and posterior parietal lobes than AD patients without these features. Within the AD group, correlations were found between neuropsychological tests and rCBF: praxis correlated with posterior parietal activity, memory with left temporal lobe activity and language with activity throughout the left hemisphere. Images PMID:2467967

  6. Brain single-photon emission CT physics principles.

    PubMed

    Accorsi, R

    2008-08-01

    The basic principles of scintigraphy are reviewed and extended to 3D imaging. Single-photon emission computed tomography (SPECT) is a sensitive and specific 3D technique to monitor in vivo functional processes in both clinical and preclinical studies. SPECT/CT systems are becoming increasingly common and can provide accurately registered anatomic information as well. In general, SPECT is affected by low photon-collection efficiency, but in brain imaging, not all of the large FOV of clinical gamma cameras is needed: The use of fan- and cone-beam collimation trades off the unused FOV for increased sensitivity and resolution. The design of dedicated cameras aims at increased angular coverage and resolution by minimizing the distance from the patient. The corrections needed for quantitative imaging are challenging but can take advantage of the relative spatial uniformity of attenuation and scatter. Preclinical systems can provide submillimeter resolution in small animal brain imaging with workable sensitivity.

  7. Optical nanoantennas: controlled emission of single photon sources

    NASA Astrophysics Data System (ADS)

    van Hulst, Niek

    2011-03-01

    Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles, due to their omnidirectional interaction with freely propagating light and due to limits of diffraction. Optical nanoantennas offer both nanoscale localization and efficient interaction. Here we focus on the control of the interaction of single photon emitters (molecules, quantum dots) with radiation through metal nanorod antennas. First a novel analytical model is presented, which shows the continuous evolution of the properties of optical antennas as they become increasingly bound, i.e. plasmonic. The model accurately describes the complete emission process, the radiative decay rate, quantum efficiency, and angular emission, moreover gives a quantitative description of the gradual emergence of sub-radiant, super-radiant, and dark modes. Next we investigate experimentally the coupling of a single quantum dot to a nanorod of increasing length. The angular luminescence of the quantum dot is detected through increasingly higher order antenna modes. Simultaneously the emission is strongly polarized and enhanced. Direct confrontation with theory allows to determine the coupling efficiency of the quantum dot to the antenna. Finally, we present unidirectional emission of a single emitter by coupling to a nanofabricated Yagi-Uda antenna. A quantum dot is placed in the near field of the antenna so that it drives the resonant feed element of the antenna. The resulting quantum-dot luminescence is strongly polarized and highly directed into a narrow forward angular cone. The directionality of the quantum dot can be controlled by tuning the antenna dimensions. Thus our results show the potential of optical antennas to communicate energy to, from, and between nano-emitters. A.G.Curto et al., Science 329, 930 (2010)

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

    SciTech Connect

    Not Available

    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)

  9. Stress-first single photon emission computed myocardial perfusion imaging

    PubMed Central

    Aquino, C I; Scarano, M; Squame, F; Casaburi, G; Nori, S L; Pace, L

    2016-01-01

    Background Myocardial perfusion imaging (MPI) with single photon emission tomography (SPET) is widely used in coronary artery disease evaluation. Recently major dosimetric concerns have arisen. The aim of this study was to evaluate if a pre-test scoring system could predict the results of stress SPET MPI, thus avoiding two radionuclide injections. Methods All consecutive patients (n=309) undergoing SPET MPI during the first 6 months of 2014 constituted the study group. The scoring system is based on these characteristics: age >65 years (1 point), diabetes (2 points), typical chest pain (2 points), congestive heart failure (3 points), abnormal ECG (4 points), male gender (4 points), and documented previous CAD (5 points). The patients were divided on the basis of the prediction score into 3 classes of risk for an abnormal stress-first protocol. Results An abnormal stress SPET MPI was present in 7/31 patients (23%) with a low risk score, in 24/90 (27%) with an intermediate score risk, and in 124/188 (66%) with an high score risk. ROC curve analysis showed good prediction of abnormal stress MPI. Conclusions Our results suggest an appropriate use of a pre-test clinical prediction formula of abnormal stress MPI in a routine clinical setting. PMID:27896227

  10. Brain single photon emission computed tomography in neonates

    SciTech Connect

    Denays, R.; Van Pachterbeke, T.; Tondeur, M.; Spehl, M.; Toppet, V.; Ham, H.; Piepsz, A.; Rubinstein, M.; Nol, P.H.; Haumont, D. )

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Single-photon emission of two-level system via rapid adiabatic passage

    NASA Astrophysics Data System (ADS)

    Miao, Qiang; Zheng, Yujun

    2016-09-01

    In this paper, we present a high quality single-photon source based on the two-level system undergoing rapid adiabatic passage (RAP). A trigger strategy (sweet region) is suggested to optimize the single-photon emission and explain a counter-intuitive phenomenon on the optimal parameters. The RAP strategy of single-photon source is robust against control error and environmental fluctuation.

  13. Single-photon emission of two-level system via rapid adiabatic passage

    PubMed Central

    Miao, Qiang; Zheng, Yujun

    2016-01-01

    In this paper, we present a high quality single-photon source based on the two-level system undergoing rapid adiabatic passage (RAP). A trigger strategy (sweet region) is suggested to optimize the single-photon emission and explain a counter-intuitive phenomenon on the optimal parameters. The RAP strategy of single-photon source is robust against control error and environmental fluctuation. PMID:27601295

  14. Single photon emission computed tomography (SPECT) and SPECT/low-dose computerized tomography did not increase sensitivity or specificity compared to planar bone scintigraphy for detection of bone metastases in advanced breast cancer.

    PubMed

    Haraldsen, Ate; Bluhme, Henrik; Røhl, Lisbeth; Pedersen, Erik Morre; Jensen, Anders Bonde; Hansen, Eva Boysen; Nellemann, Hanne; Rasmussen, Finn; Morsing, Anni

    2016-01-01

    To evaluate and compare the diagnostic performance of whole-body planar bone scintigraphy (WBS), single photon emission computed tomography (SPECT), SPECT/low-dose computerized tomography (SPECT/ldCT) and SPECT/contrast enhanced diagnostic CT (SPECT/cdCT) in the staging of patients with advanced breast cancer. Seventy-eight patients with recurrence of biopsy-proven breast cancer and suspicion of disseminated disease were investigated with WBS, SPECT, SPECT/ldCT, SPECT/cdCT and MRI performed on the same day in this prospective study. Images were separately analysed in a blinded fashion by radiologists and nuclear medicine physicians regarding the presence of pathological findings. MRI served as reference standard. According to reference standard, 38 of 73 patients had bone metastases. The sensitivity was 87%, 87%, 79%, and 84% and specificity 63%, 71%, 63% and 83% for WBS, SPECT, SPECT/ldCT and SPECT/cdCT. A significantly increased specificity of SPECT/cdCT compared to WBS and SPECT/ldCT was found, and other parameters did not differ significantly between modalities. Additional two patients had bone metastases solely located outside the MRI scan field and seven patients had soft tissue metastases, but no skeletal changes on MRI. WBS, SPECT and SPECT/ldCT were less sensitive than MRI and equally specific for the detection of bone metastases in patients with advanced breast cancer. Based on our findings, we suggest that initial staging include WBS, MRI of the spine and CT for soft tissue evaluation. Further studies may clarify the potential benefits of whole-body MRI and 18F-NaF PET/CT or 18F-FDG PET/CT. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  15. Ictal single photon emission computed tomography of myoclonic absence seizures.

    PubMed

    Ikeda, Hiroko; Imai, Katsumi; Ikeda, Hitoshi; Matsuda, Kazumi; Takahashi, Yukitoshi; Inoue, Yushi

    2017-08-16

    Epilepsy with myoclonic absences (EMAs) is a rare epileptic disorder characterized by a predominant type of seizures, myoclonic absences (MAs). The pathophysiology of MAs in patients with EMAs remains unknown. Here, we report the first characterization of the ictal phase of MAs by single photon emission computed tomography (SPECT). We evaluated 1 male (Patient 1) and 1 female (Patient 2) patient with EMAs, aged 8 and 4years at first SPECT investigation, respectively. We performed ictal and interictal (99 m)Tc-ethyl cysteinate dimer (ECD) SPECT. We then generated images of subtraction ictal SPECT co-registered to MRI (SISCOM) from the interictal and ictal data to evaluate topographic changes in cerebral blood flow (CBF) during MAs as compared to the interictal state. In Patient 1, the CBF increased in the perirolandic areas, thalamus, caudate nucleus, and precuneus, and decreased in the middle frontal gyrus and bilateral orbitofrontal regions. In Patient 2, CBF increased in the thalamus, putamen, and globus pallidus. In contrast to the CBF in Patient 1, CBF was decreased in the precuneus. Using SPECT, we showed that, in addition to the thalamus and basal ganglia, the perirolandic cortical motor area is involved in MAs. We hypothesize that in MAs the blood perfusion in the perirolandic cortical motor area might have changed under the influence of the cortico-thalamic network oscillation features. The CBF properties observed by means of our SPECT procedure may represent key features of the pathophysiological mechanisms underlying MAs. Copyright © 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  16. [Ventricular volumes determined by single-photon emission computed tomography].

    PubMed

    Katohno, E; Ono, K; Owada, K; Fujino, A; Watanabe, N; Sato, M; Konno, I; Yaoita, H; Tsuda, F; Kariyone, S

    1987-06-01

    To determine right (RV) and left ventricular (LV) volumes, a new technique was developed using ECG-gated single-photon emission computed tomography (SPECT). RV volumes of nine patients and LV volumes of 22 patients measured by SPECT and biplane contrast cineangiography were compared. In addition, volume and ejection fraction (EF) of the RV and LV were obtained by SPECT for 10 normal controls, 21 patients with old myocardial infarction (OMI), eight patients with hypertrophic cardiomyopathy (HCM) and 12 patients with dilated cardiomyopathy (DCM), and these results were compared. The intracardiac blood pool was labeled with Tc-99m sodium pertechnetate and 32 images were recorded through 180 degrees by a rotating gamma-camera. End-diastolic and end-systolic counts during 50 msec were recorded during 50 or 60 cardiac cycles. These counting data were reconstructed as tomographic images of vertical long-axial slices with thickness of a pixel without any attenuation correction. The numbers of voxels within the % cut-off level were summed, and the sum was multiplied by the one voxel volume. The cut-off level for ventricular delineation was determined as 45% by phantom studies. 1. The values obtained from SPECT and contrast angiography correlated well. 2. In normal controls, LV end-diastolic and end-systolic volumes were significantly less than those of the RV (p less than 0.05, p less than 0.001) and LVEF was significantly greater than the RVEF (p less than 0.001). 3. In OMI (single vessel disease), both end-diastolic and end-systolic volumes of the LV were significantly greater than those of normals (p less than 0.01, p less than 0.001) and LVEF was significantly less. In HCM end-systolic volumes of the RV were significantly less (p less than 0.05) than those of the normals. 4. LV volume was greater and LVEF was extremely low both in DCM and in OMI (multivessel disease) compared to that of the normals. In DCM, RV end-systolic volumes was greater and RVEF was lower than

  17. Quantum information-holding single-photon router based on spontaneous emission

    NASA Astrophysics Data System (ADS)

    Yan, GuoAn; Qiao, HaoXue; Lu, Hua; Chen, AiXi

    2017-09-01

    In this paper, we propose a single-photon router via the use of a four-level atom system coupled with two one-dimensional coupled-resonator waveguides. A single photon can be directed from one quantum channel into another by atomic spontaneous emission. The coherent resonance and the photonic bound states lead to the perfect reflection appearing in the incident channel. The fidelity of the atom is related to the magnitude of the coupling strength and can reach unit when the coupling strength matches g a = g b . This shows that the transfer of a single photon into another quantum channel has no influence on the fidelity at special points.

  18. Single photon emission from deep-level defects in monolayer WS e2

    NASA Astrophysics Data System (ADS)

    Ye, Yanxia; Dou, Xiuming; Ding, Kun; Chen, Yu; Jiang, Desheng; Yang, Fuhua; Sun, Baoquan

    2017-06-01

    We report an efficient method to observe single photon emissions in monolayer WS e2 by applying hydrostatic pressure. The photoluminescence peaks of typical two-dimensional excitons show a nearly identical pressure-induced blueshift, whereas the energy of pressure-induced discrete emission lines (quantum emitters) demonstrates a pressure insensitive behavior. The decay time of these discrete line emissions is approximately 10 ns, which is at least one order longer than the lifetime of the broad localized (L ) excitons. These characteristics lead to a conclusion that the excitons bound to deep-level defects can be responsible for the observed single photon emissions.

  19. Brain uptake of iomazenil in cirrhotic patients: a single photon emission tomography study.

    PubMed

    Kapczinski, F; Quevedo, J; Curran, H V; Fleminger, S; Toone, B; Cluckie, A; Lader, M

    1999-01-01

    Brain uptake of 123I-iomazenil was studied in seven cirrhotic patients and eight normal controls using single photon emission computerized tomography. The highest concentration of the ligand was found in the occipital cortex, which corresponds to the brain region with the highest concentration of benzodiazepine receptors. The peak uptake was delayed in patients across all brain regions. The uptake in occipital cortex was higher in low albumin cirrhotics. Patients with low albumin also presented a more delayed peak uptake in occipital cortex and a higher volume of distribution of iomazenil in plasma, compared to patients with normal albumin levels and controls. The changes in brain uptake (delayed peak uptake and increased maximal uptake in occipital cortex) appears to reflect changes in the pharmacokinetics of the ligand, particularly in cirrhotics with low levels of plasma albumin. The curve of brain uptake of the tracer was modelled into a two compartments equation, which seems to provide a practical and reliable method to calculate the slopes of acquisition and decay, time to peak and maximal acquisition.

  20. Quantum-confined single photon emission at room temperature from SiC tetrapods.

    PubMed

    Castelletto, Stefania; Bodrog, Zoltán; Magyar, Andrew P; Gentle, Angus; Gali, Adam; Aharonovich, Igor

    2014-09-07

    Controlled engineering of isolated solid state quantum systems is one of the most prominent goals in modern nanotechnology. In this letter we demonstrate a previously unknown quantum system namely silicon carbide tetrapods. The tetrapods have a cubic polytype core (3C) and hexagonal polytype legs (4H)--a geometry that creates spontaneous polarization within a single tetrapod. Modeling of the tetrapod structures predicts that a bound exciton should exist at the 3C-4H interface. The simulations are confirmed by the observation of fully polarized and narrowband single photon emission from the tetrapods at room temperature. The single photon emission provides important insights into understanding the quantum confinement effects in non-spherical nanostructures. Our results pave the way to a new class of crystal phase nanomaterials that exhibit single photon emission at room temperature and therefore are suitable for sensing, quantum information and nanophotonics.

  1. Quantum-confined single photon emission at room temperature from SiC tetrapods

    NASA Astrophysics Data System (ADS)

    Castelletto, Stefania; Bodrog, Zoltán; Magyar, Andrew P.; Gentle, Angus; Gali, Adam; Aharonovich, Igor

    2014-08-01

    Controlled engineering of isolated solid state quantum systems is one of the most prominent goals in modern nanotechnology. In this letter we demonstrate a previously unknown quantum system namely silicon carbide tetrapods. The tetrapods have a cubic polytype core (3C) and hexagonal polytype legs (4H) - a geometry that creates spontaneous polarization within a single tetrapod. Modeling of the tetrapod structures predicts that a bound exciton should exist at the 3C-4H interface. The simulations are confirmed by the observation of fully polarized and narrowband single photon emission from the tetrapods at room temperature. The single photon emission provides important insights into understanding the quantum confinement effects in non-spherical nanostructures. Our results pave the way to a new class of crystal phase nanomaterials that exhibit single photon emission at room temperature and therefore are suitable for sensing, quantum information and nanophotonics.Controlled engineering of isolated solid state quantum systems is one of the most prominent goals in modern nanotechnology. In this letter we demonstrate a previously unknown quantum system namely silicon carbide tetrapods. The tetrapods have a cubic polytype core (3C) and hexagonal polytype legs (4H) - a geometry that creates spontaneous polarization within a single tetrapod. Modeling of the tetrapod structures predicts that a bound exciton should exist at the 3C-4H interface. The simulations are confirmed by the observation of fully polarized and narrowband single photon emission from the tetrapods at room temperature. The single photon emission provides important insights into understanding the quantum confinement effects in non-spherical nanostructures. Our results pave the way to a new class of crystal phase nanomaterials that exhibit single photon emission at room temperature and therefore are suitable for sensing, quantum information and nanophotonics. Electronic supplementary information (ESI) available

  2. p-Shell Rabi-flopping and single photon emission in an InGaAs/GaAs quantum dot

    NASA Astrophysics Data System (ADS)

    Ester, P.; Lackmann, L.; Hübner, M. C.; Michaelis de Vasconcellos, S.; Zrenner, A.; Bichler, M.

    2008-04-01

    Very clean single photon emission from a single InGaAs/GaAs quantum dot is demonstrated by the use of a coherent optical state preparation. We present a concept for single photon emission, which uses p-shell Rabi-flopping followed by a sequence of relaxation and recombination. The proof of the (clean) single photon emission is performed by photon correlation measurements.

  3. Polarisation-controlled single photon emission at high temperatures from InGaN quantum dots.

    PubMed

    Wang, T; Puchtler, T J; Zhu, T; Jarman, J C; Nuttall, L P; Oliver, R A; Taylor, R A

    2017-07-13

    Solid-state single photon sources with polarisation control operating beyond the Peltier cooling barrier of 200 K are desirable for a variety of applications in quantum technology. Using a non-polar InGaN system, we report the successful realisation of single photon emission with a g((2))(0) of 0.21, a high polarisation degree of 0.80, a fixed polarisation axis determined by the underlying crystallography, and a GHz repetition rate with a radiative lifetime of 357 ps at 220 K in semiconductor quantum dots. The temperature insensitivity of these properties, together with the simple planar epitaxial growth method and absence of complex device geometries, demonstrates that fast single photon emission with polarisation control can be achieved in solid-state quantum dots above the Peltier temperature threshold, making this system a potential candidate for future on-chip applications in integrated systems.

  4. Kinetics of single-photon emission from electrically pumped NV centers in diamond

    NASA Astrophysics Data System (ADS)

    Khramtsov, I. A.; Agio, M.; Fedyanin, D. Yu.

    2017-09-01

    Nitrogen-vacancy centers in diamond are considered to be promising building blocks for emerging quantum technologies. At the same time, practical applications require them to be excited and controlled electrically. However, there is a lack of knowledge about their behavior in electrical driven systems. Here, we introduce a physical model to address the single-photon emission dynamics of electrically pumped NV center in diamond in a quantitative manner and present a detailed study of the single-photon emitting diode based on NV centers.

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

    NASA Astrophysics Data System (ADS)

    Weiß, M.; Kapfinger, S.; Reichert, T.; Finley, J. J.; Wixforth, A.; Kaniber, M.; Krenner, H. J.

    2016-07-01

    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 fSAW ≃ 800 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.

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

    PubMed

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

    2014-02-10

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

  7. Single-Photon Emission of a Hydrogenlike Atom

    NASA Astrophysics Data System (ADS)

    Skobelev, V. V.

    2016-11-01

    Implementing a previously obtained, original solution of the Dirac equation for an electron in the field of a nucleus ( Ze) expressed in terms of the wave function of the corresponding Schrödinger equation and its derivatives in spherical coordinates and the spin projection operator Σ3 associated with the eigenfunction, taking into account in each component of the spinor the leading term of the expansion in the small parameter ( Zα), α = e 2 / ħc ≈ 1 / 137, the partial probabilities W of emission of a photon ( Zα)* → ( Zα) + γ have been calculated. Here two orthogonal states of the linear polarization of the photon, and also the spin states of the electron, which previously had not been taken into consideration, have been taken into account in the transverse gauge. It turns out that the probabilities W of emission of a photon per unit time for any allowed transitions are proportional to (Zα)4, as was previously accepted, and the selection rules for the quantum number m have the usual form ∆ m = 0,±1. It was found that a spin flip does not take place during emission. In contrast to the customary situation with the selection rules for the quantum number l being of the form ∆ l = ±1, for ∆ m = ±1 there also exist integrals over dcosθ which are not equal to zero for undetermined odd values of ∆ l. In this, and also in a fundamentally different dependence of the amplitude on the quantum numbers consist the differences from the traditional approach to the problem. Necessary conditions are formulated, under the fulfillment of which the selection rules for l are not changed, having values ∆ l = ±1 for arbitrary ∆ m, but it was not possible, however, to give a complete proof of these rules.

  8. Positron emission tomography and single-photon emission computed tomography in substance abuse research.

    PubMed

    Volkow, Nora D; Fowler, Joanna S; Wang, Gene-Jack

    2003-04-01

    Many advances in the conceptualization of addiction as a disease of the brain have come from the application of imaging technologies directly in the human drug abuser. New knowledge has been driven by advances in radiotracer design and chemistry and positron emission tomography (PET) and single-photon emission computed tomography (SPECT) instrumentation and the integration of these scientific tools with the tools of biochemistry, pharmacology, and medicine. This topic cuts across the medical specialties of neurology, psychiatry, oncology, and cardiology because of the high medical, social, and economic toll that drugs of abuse, including the legal drugs, cigarettes and alcohol, take on society. This article highlights recent advances in the use of PET and SPECT imaging to measure the pharmacokinetic and pharmacodynamic effects of drugs of abuse on the human brain.

  9. Calorimetry in Medical Applications: Single-Photon Emission Computed Tomography and Positron Emission Tomography

    SciTech Connect

    Chen, C.-T.

    2006-10-27

    Positron emission tomography (PET) and single-photon emission computed tomography (SPECT), two nuclear medicine imaging modalities broadly used in clinics and research, share many common instrumentation, detector, and electronics technology platforms with calorimetry in high-energy physics, astronomy, and other physics sciences. Historically, advances made in calorimetry had played major roles in the development of novel approaches and critical technologies essential to the evolution of PET and SPECT. There have also been examples in which PET/SPECT developments had led to new techniques in calorimetry for other application areas. In recent years, several innovations have propelled advances in both calorimetry in general and PET/SPECT in particular. Examples include time-of-flight (TOF) measurements, silicon photomultipliers (SiPMs), etc.

  10. Dynamics of Single-Photon Emission from Electrically Pumped Color Centers

    NASA Astrophysics Data System (ADS)

    Khramtsov, Igor A.; Agio, Mario; Fedyanin, Dmitry Yu.

    2017-08-01

    Low-power, high-speed, and bright electrically driven true single-photon sources, which are able to operate at room temperature, are vital for the practical realization of quantum-communication networks and optical quantum computations. Color centers in semiconductors are currently the best candidates; however, in spite of their intensive study in the past decade, the behavior of color centers in electrically controlled systems is poorly understood. Here we present a physical model and establish a theoretical approach to address single-photon emission dynamics of electrically pumped color centers, which interprets experimental results. We support our analysis with self-consistent numerical simulations of a single-photon emitting diode based on a single nitrogen-vacancy center in diamond and predict the second-order autocorrelation function and other emission characteristics. Our theoretical findings demonstrate remarkable agreement with the experimental results and pave the way to the understanding of single-electron and single-photon processes in semiconductors.

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

    PubMed

    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.

  12. Cascaded emission of single photons from the biexciton in monolayered WSe2

    PubMed Central

    He, Yu-Ming; Iff, Oliver; Lundt, Nils; Baumann, Vasilij; Davanco, Marcelo; Srinivasan, Kartik; Höfling, Sven; Schneider, Christian

    2016-01-01

    Monolayers of transition metal dichalcogenide materials emerged as a new material class to study excitonic effects in solid state, as they benefit from enormous Coulomb correlations between electrons and holes. Especially in WSe2, sharp emission features have been observed at cryogenic temperatures, which act as single photon sources. Tight exciton localization has been assumed to induce an anharmonic excitation spectrum; however, the evidence of the hypothesis, namely the demonstration of a localized biexciton, is elusive. Here we unambiguously demonstrate the existence of a localized biexciton in a monolayer of WSe2, which triggers an emission cascade of single photons. The biexciton is identified by its time-resolved photoluminescence, superlinearity and distinct polarization in micro-photoluminescence experiments. We evidence the cascaded nature of the emission process in a cross-correlation experiment, which yields a strong bunching behaviour. Our work paves the way to a new generation of quantum optics experiments with two-dimensional semiconductors. PMID:27830703

  13. Nursing benefits of using an automated injection system for ictal brain single photon emission computed tomography.

    PubMed

    Vonhofen, Geraldine; Evangelista, Tonya; Lordeon, Patricia

    2012-04-01

    The traditional method of administering radioactive isotopes to pediatric patients undergoing ictal brain single photon emission computed tomography testing has been by manual injections. This method presents certain challenges for nursing, including time requirements and safety risks. This quality improvement project discusses the implementation of an automated injection system for isotope administration and its impact on staffing, safety, and nursing satisfaction. It was conducted in an epilepsy monitoring unit at a large urban pediatric facility. Results of this project showed a decrease in the number of nurses exposed to radiation and improved nursing satisfaction with the use of the automated injection system. In addition, there was a decrease in the number of nursing hours required during ictal brain single photon emission computed tomography testing.

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

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Mueller, S.P.; Rosen, T.J.; English, R.; Nagel, J.S.; Growdon, J.H.

    1988-04-01

    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.

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

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Mueller, S.P.; Rosen, T.J.; English, R.; Nagel, J.S.; Growdon, J.H.

    1988-04-01

    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. Single photon emission computed tomography-CT in ectopic parathyroid adenoma

    PubMed Central

    Kumar, K. V. S. Hari; Jha, Sangeeta; Shaikh, Altamash; Modi, K. D.

    2011-01-01

    Primary hyperparathyroidism often presents with protean manifestations, resulting in delayed diagnosis. At times, aberrant development and migration of the gland leads to ectopic location leading to problems in localization. Judicious use of combination methods of localization is recommended in treatment failure or recurrent disease. We report the use of single photon emission computed tomography-CT in precise localization of parathyroid adenoma in a patient with failed initial surgery. PMID:22029007

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

    PubMed

    Piccinelli, Marina; Garcia, Ernest V

    2016-02-01

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

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

    SciTech Connect

    Sugiyama, H.; Christensen, J.; Skyhoj Olsen, T.; Lassen, N.A.

    1986-11-01

    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 early lysis of the occlusion having high CBF (massive luxury perfusion) for some weeks. Evidence of this kind may be essential in the evaluation of therapeutic measures in ischemic stroke.

  19. Iofetamine I 123 single photon emission computed tomography is accurate in the diagnosis of Alzheimer's disease

    SciTech Connect

    Johnson, K.A.; Holman, B.L.; Rosen, T.J.; Nagel, J.S.; English, R.J.; Growdon, J.H. )

    1990-04-01

    To determine the diagnostic accuracy of iofetamine hydrochloride I 123 (IMP) with single photon emission computed tomography in Alzheimer's disease, we studied 58 patients with AD and 15 age-matched healthy control subjects. We used a qualitative method to assess regional IMP uptake in the entire brain and to rate image data sets as normal or abnormal without knowledge of subjects'clinical classification. The sensitivity and specificity of IMP with single photon emission computed tomography in AD were 88% and 87%, respectively. In 15 patients with mild cognitive deficits (Blessed Dementia Scale score, less than or equal to 10), sensitivity was 80%. With the use of a semiquantitative measure of regional cortical IMP uptake, the parietal lobes were the most functionally impaired in AD and the most strongly associated with the patients' Blessed Dementia Scale scores. These results indicated that IMP with single photon emission computed tomography may be a useful adjunct in the clinical diagnosis of AD in early, mild disease.

  20. Surface acoustic wave regulated single photon emission from a coupled quantum dot–nanocavity system

    SciTech Connect

    Weiß, M.; Kapfinger, S.; Wixforth, A.; Krenner, H. J.; Reichert, T.; Finley, J. J.; Kaniber, M.

    2016-07-18

    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{sub SAW} ≃ 800 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{sup (2)}. All relevant frequencies of our experiment are faithfully identified in the Fourier transform of g{sup (2)}, demonstrating high fidelity regulation of the stream of single photons emitted by the system.

  1. Single photon emission from diamond nanocrystals in an opal photonic crystal.

    PubMed

    Stewart, L A; Zhai, Y; Dawes, J M; Steel, M J; Rabeau, J R; Withford, M J

    2009-09-28

    We present the first optical measurement of a single nitrogen-vacancy (NV) center in a three-dimensional photonic crystal. The photonic crystal, fabricated by self-assembly of polystyrene microspheres, exhibits a photonic stopband that overlaps the NV photoluminescence spectrum. A modified emission spectrum and photon antibunching were measured from the NV centers. Time-resolved fluorescence measurements revealed a 30% increase in the source lifetime. Encapsulation of single NV centers in a three-dimensional photonic crystal is a step towards controlling emission properties of a single photon source.

  2. Tunable and high-purity room temperature single-photon emission from atomic defects in hexagonal boron nitride.

    PubMed

    Grosso, Gabriele; Moon, Hyowon; Lienhard, Benjamin; Ali, Sajid; Efetov, Dmitri K; Furchi, Marco M; Jarillo-Herrero, Pablo; Ford, Michael J; Aharonovich, Igor; Englund, Dirk

    2017-09-26

    Two-dimensional van der Waals materials have emerged as promising platforms for solid-state quantum information processing devices with unusual potential for heterogeneous assembly. Recently, bright and photostable single photon emitters were reported from atomic defects in layered hexagonal boron nitride (hBN), but controlling inhomogeneous spectral distribution and reducing multi-photon emission presented open challenges. Here, we demonstrate that strain control allows spectral tunability of hBN single photon emitters over 6 meV, and material processing sharply improves the single photon purity. We observe high single photon count rates exceeding 7 × 10(6) counts per second at saturation, after correcting for uncorrelated photon background. Furthermore, these emitters are stable to material transfer to other substrates. High-purity and photostable single photon emission at room temperature, together with spectral tunability and transferability, opens the door to scalable integration of high-quality quantum emitters in photonic quantum technologies.Inhomogeneous spectral distribution and multi-photon emission are currently hindering the use of defects in layered hBN as reliable single photon emitters. Here, the authors demonstrate strain-controlled wavelength tuning and increased single photon purity through suitable material processing.

  3. Narrow-band single-photon emission in the near infrared for quantum key distribution.

    PubMed

    Wu, E; Jacques, Vincent; Zeng, Heping; Grangier, Philippe; Treussart, François; Roch, Jean-François

    2006-02-06

    We present a detailed study of photophysical properties of single color centers in natural diamond samples emitting in the near infrared under optical excitation. Photoluminescence of these single emitters has several striking features, including narrow-band (FWHM 2 nm) fully polarized emission around 780 nm, a short excited-state lifetime of about 2 ns, and perfect photostability at room temperature under our excitation conditions. Development of a triggered single-photon source relying on this single color center is discussed for application to quantum key distribution.

  4. Painful spondylolysis or spondylolisthesis studied by radiography and single-photon emission computed tomography

    SciTech Connect

    Collier, B.D.; Johnson, R.P.; Carrera, G.F.; Meyer, G.A.; Schwab, J.P.; Flatley, T.J.; Isitman, A.T.; Hellman, R.S.; Zielonka, J.S.; Knobel, J.

    1985-01-01

    Planar bone scintigraphy (PBS) and single-photon emission computed tomography (SPECT) were compared in 19 adults with radiographic evidence of spondylolysis and/or spondylolisthesis. SPECT was more sensitive than PBS when used to identify symptomatic patients and sites of painful defects in the pars interarticularis. In addition, SPECT allowed more accurate localization than PBS. In 6 patients, spondylolysis or spondylolisthesis was unrealted to low back pain, and SPECT images of the posterior neural arch were normal. The authors conclude that when spondylolysis or spondylolisthesis is the cause of low back pain, pars defects are frequently heralded by increased scintigraphic activity which is best detected and localized by SPECT.

  5. Single photon emission computed tomography/computed tomography of the skull in malignant otitis externa.

    PubMed

    Chakraborty, Dhritiman; Bhattacharya, Anish; Kamaleshwaran, Koramadai Karuppusamy; Agrawal, Kanhaiyalal; Gupta, Ashok Kumar; Mittal, Bhagwant Rai

    2012-01-01

    Malignant otitis externa is a severe, rare infective condition of the external auditory canal and skull base. The diagnosis is generally made from a range of clinical, laboratory, and imaging findings. Technetium 99m methylene diphosphonate bone scintigraphy is known to detect osteomyelitis earlier than computed tomography. The authors present a patient with bilateral malignant otitis externa where the extent of skull base involvement was determined on 3-phase bone scintigraphy with single photon emission computed tomography/computed tomography. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography.

    PubMed

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Simulation Study of Single Photon Emission Computed Tomography for Industrial Applications

    SciTech Connect

    Roy, Tushar; Sarkar, P. S.; Sinha, Amar

    2008-09-26

    SPECT (Single Photon Emission Computed Tomography) provides for an invaluable non-invasive technique for the characterization and activity distribution of the gamma-emitting source. For many applications of radioisotopes for medical and industrial application, not only the positional information of the distribution of radioisotopes is needed but also its strength. The well-established X-ray radiography or transmission tomography techniques do not yield sufficient quantitative information about these objects. Emission tomography is one of the important methods for such characterization. Application of parallel beam, fan beam and 3D cone beam emission tomography methods have been discussed in this paper. Simulation studies to test these algorithms have been carried out to validate the technique.

  9. Imaging in breast cancer: Single-photon computed tomography and positron-emission tomography

    PubMed Central

    Bénard, François; Turcotte, Éric

    2005-01-01

    Although mammography remains a key imaging method for the early detection and screening of breast cancer, the overall accuracy of this test remains low. Several radiopharmaceuticals have been proposed as adjunct imaging methods to characterize breast masses by single-photon-emission computed tomography (SPECT) and positron-emission tomography (PET). Useful in characterizing indeterminate palpable masses and in the detection of axillary metastases, these techniques are insufficiently sensitive to detect subcentimetric tumor deposits. Their role in staging nodal involvement of the axillary areas therefore currently remains limited. Several enzymes and receptors have been targeted for imaging breast cancers with PET. [18F]Fluorodeoxyglucose is particularly useful in the detection and staging of recurrent breast cancer and in assessing the response to chemotherapy. Several other ligands targeting proliferative activity, protein synthesis, and hormone and cell-membrane receptors may complement this approach by providing unique information about biological characteristics of breast cancer across primary and metastatic tumor sites. PMID:15987467

  10. Dementias appear to have individual profiles in single photon emission computed tomography

    SciTech Connect

    Not Available

    1989-02-17

    A number of researchers are seeking clinical applications for single photon emission computed tomographic (SPECT) images of demented patients. They have found that dementias have somewhat individual SPECT profiles. The challenge now, they say, is to determine if the SPECT information is meaningful to the clinician and to develop more specific radiotracers, such as tracers for individual neuroreceptors. The initial work was done with positron emission tomography (PET), a sometimes more sensitive, but much more expensive technique. Recently, a number of centers began trying to duplicate the PET findings using SPECT. Developing SPECT could actually make dementia scanning fairly available, they say. Radiologists estimate that three fourths of the nation's nuclear medicine departments have SPECT scanning machines-either rotating or multiaperature gamma cameras.

  11. Brain single photon emission computed tomography: Newer activation and intervention studies

    SciTech Connect

    Tikofsky, R.S.; Hellman, R.S. )

    1991-01-01

    Single-photon emission computed tomography (SPECT) regional cerebral blood flow (rCBF) findings using non-xenon 133 tracers in combination with activation and intervention techniques are reviewed. Examination of the currently available data indicates that it is possible to detect the effects of a variety of activations and interventional procedures using SPECT rCBF with non-xenon 133 tracers. There are still many issues to be resolved before SPECT can reach the level of sophistication attained by xenon 133 and positron emission tomography in studying rCBF during activation or intervention. However, research to date indicates that SPECT rCBF studied with tracers other than xenon 133 has an excellent potential for increasing the ability to differentiate normal and pathological states. 97 refs.

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

    SciTech Connect

    Knapp, F.F. Jr.; McPherson, D.W.

    1992-01-01

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

    SciTech Connect

    Knapp, F.F. Jr.; McPherson, D.W.

    1992-03-01

    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.

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

    SciTech Connect

    Fine, D.G.; Clements, I.P.; Callahan, M.J.

    1989-05-01

    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.

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

    PubMed Central

    Patel, Mehul; Satishchandra, Parthasarathy; Aravinda, Hanumanthapura; Bharath, Rose D.; Sinha, Sanjib

    2014-01-01

    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. PMID:25506178

  16. Tc99m HM-PAO single photon emission computed tomography in temporal lobe epilepsy.

    PubMed

    Duncan, R; Patterson, J; Hadley, D M; Wyper, D J; McGeorge, A P; Bone, I

    1990-04-01

    We present the results of single photon emission computed tomography (SPECT) in 40 patients with temporal lobe epilepsy and normal computed transmission tomography (CT). Abnormalities of regional cerebral blood flow were found in 26 patients. There was focal hypoperfusion alone in 14, focal hyperperfusion alone in 6, and both types of abnormality in 6. In 4 patients there were bilateral abnormalities. Repeat SPECT showed persistence of interictal hyperperfusion in 5/12 patients. There were no significant correlations between SPECT findings and clinical parameters, and no relation between the persistence of interictal hyperperfusion and time since last seizure or seizure frequency. Where SPECT and multiple surface EEG recordings were both lateralising, agreement between them was good. The results of this study support the usefulness of HMPAO SPECT in detecting lateralising abnormalities in temporal lobe epilepsy. Interictal hyperperfusion may be commoner than previous publications suggest, and may be persistent in some cases.

  17. High-energy two-electron capture with emission of a single photon

    SciTech Connect

    Drukarev, E. G.; Mikhailov, A. I.; Mikhailov, I. A.; Scheid, W.

    2007-12-15

    We investigate the two-electron capture with emission of a single photon to the ground state in the Coulomb field of a heavy nucleus in its collision with a light atom. Describing electron-electron interactions in the bound state perturbatively, we obtained an analytical formula for the high-energy limit of the cross section. In combination with previous results obtained in the same approach we calculated the cross section in a broad interval of energies of the collision. We show that the amplitude of the process at high energy depends on the behavior of the bound state wave function near the triple coalescence point. We analyze the properties of the approximate wave functions which are necessary for the description of the high-energy limit.

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

    PubMed Central

    Santra, Amburanjan; Kumar, Rakesh

    2014-01-01

    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. PMID:25400359

  19. Detection of avascular necrosis in adults by single photon emission computed tomography

    SciTech Connect

    Collier, B.D.; Johnston, R.P.; Carrera, G.; Isitman, A.T.; Hellman, R.S.; Zielonka, J.S.

    1984-01-01

    Twenty-one adult patients with the clinical diagnosis of avascular necrosis (AVN) of the femoral head were examined with planar bone scintigraphy (high resolution collimator) and single photon emission computed tomography (SPECT). The duration of hip pain ranged from 1 day to 18 months. Risk factors (including steroids, renal transplantation, alcoholism, and trauma) were present in 17 cases. A final diagnosis of AVN (20 hips), osteochondral facture, or stress fracture, was established for 17 patients. The 4 remaining patients, who were radiographically normal and did not complain of pain 3 months later, were thought to have no significant bone pathology. SPECT and planar bone scintigraphy were reported as positive for AVN only if a photopenic bony defect could be identified. In particular, uniformly increased activity throughout the femoral head was not considered to be diagnostic of AVN. The authors conclude that by identifying a photopenic defect which is not evident on planar bone scintigraphy, SPECT can contribute to accurate diagnosis of AVN.

  20. Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yılmaz; Vatankulu, Betül; Uslu, Lebriz; Halac, Metin

    2016-01-01

    An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images. PMID:27385906

  1. Single-photon emission computed tomography in human immunodeficiency virus encephalopathy: A preliminary report

    SciTech Connect

    Masdeu, J.C.; Yudd, A.; Van Heertum, R.L.; Grundman, M.; Hriso, E.; O'Connell, R.A.; Luck, D.; Camli, U.; King, L.N. )

    1991-08-01

    Depression or psychosis in a previously asymptomatic individual infected with the human immunodeficiency virus (HIV) may be psychogenic, related to brain involvement by the HIV or both. Although prognosis and treatment differ depending on etiology, computed tomography (CT) and magnetic resonance imaging (MRI) are usually unrevealing in early HIV encephalopathy and therefore cannot differentiate it from psychogenic conditions. Thirty of 32 patients (94%) with HIV encephalopathy had single-photon emission computed tomography (SPECT) findings that differed from the findings in 15 patients with non-HIV psychoses and 6 controls. SPECT showed multifocal cortical and subcortical areas of hypoperfusion. In 4 cases, cognitive improvement after 6-8 weeks of zidovudine (AZT) therapy was reflected in amelioration of SPECT findings. CT remained unchanged. SPECT may be a useful technique for the evaluation of HIV encephalopathy.

  2. Single photon emission computed tomography (SPECT) findings of a patient with a novel prion mutation.

    PubMed

    Matsuzono, Kosuke; Morihara, Ryuta; Sato, Kota; Hishikawa, Nozomi; Yamashita, Toru; Deguchi, Kentaro; Abe, Koji

    2015-01-01

    We experienced a unique case of familial prion disease with a prion gene mutation that caused pan-autonomic failure, sensory neuropathy and mild cognitive impairment. No abnormal sites of intensity were observed on diffusion-weighted magnetic resonance image (MRI) over six to 11 years or fluid attenuated inversion recovery MRI at six or nine years. However, (99m)Tc-ethylcysteinate dimer single photon emission computed tomography (SPECT) showed a decreased cerebral blood flow in the bilateral parietal and occipital lobes at nine years, which then expanded at 11 years, corresponding to mild atrophy in these areas on MRI. In some cases of prion mutations, particularly the slowly progressive type, SPECT may show abnormalities, while MRI does not.

  3. Diagnosis of partial and total physeal arrest by bone single-photon emission computed tomography.

    PubMed

    Wioland, M; Bonnerot, V

    1993-09-01

    Bone single-photon emission computed tomography (SPECT), capable of creating maps of the distribution of osteoblastic activity in every spatial plane of a physis, should provide images of diagnostic value in the case of patients suffering from growth arrests (epiphysiodeses). Seventy-five bone SPECT scans were obtained in 64 children suspected to have developed physeal arrests. The transaxial slices of the physis, in the case of partial epiphysiodeses: (a) indicated the percentage of the remaining normal physis, (b) located the bony bridge within the physis and (c) showed the slowdown of the growth of the remaining normal physis induced by the bony bridge in some children. Misdiagnosis occurred in six patients. For total epiphysiodeses, the radionuclide diagnosis was confirmed in 20 of 21 patients. Radionuclide, x-ray and MRI examinations in the study of growth disturbances were found to be complementary.

  4. Room-temperature triggered single photon emission from a III-nitride site-controlled nanowire quantum dot.

    PubMed

    Holmes, Mark J; Choi, Kihyun; Kako, Satoshi; Arita, Munetaka; Arakawa, Yasuhiko

    2014-02-12

    We demonstrate triggered single photon emission at room temperature from a site-controlled III-nitride quantum dot embedded in a nanowire. Moreover, we reveal a remarkable temperature insensitivity of the single photon statistics, and a g((2))[0] value at 300 K of just 0.13. The combination of using high-quality, small, site-controlled quantum dots with a wide-bandgap material system is crucial for providing both sufficient exciton confinement and an emission spectrum with minimal contamination in order to enable room temperature operation. Arrays of such single photon emitters will be useful for room-temperature quantum information processing applications such as on-chip quantum communication.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Solid-state quantum emitters, such as the nitrogen-vacancy centre in diamond, are robust systems for practical realizations of various quantum information processing protocols and nanoscale magnetometry schemes 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 resonators, 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 emitter-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.

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

    SciTech Connect

    Quitsch, Wolf; Kümmell, Tilmar; Bacher, Gerd; Gust, Arne; Kruse, Carsten; Hommel, Detlef

    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.

  7. Tunable room-temperature single-photon emission at telecom wavelengths from sp3 defects in carbon nanotubes

    DOE PAGES

    He, Xiaowei; Hartmann, Nicolai F.; Ma, Xuedan; ...

    2017-07-31

    Generating quantum light emitters that operate at room temperature and at telecom wavelengths remains a significant materials challenge. To achieve this goal requires light sources that emit in the near-infrared wavelength region and that, ideally, are tunable to allow desired output wavelengths to be accessed in a controllable manner. Here, we show that exciton localization at covalently introduced aryl sp3 defect sites in single-walled carbon nanotubes provides a route to room-temperature single-photon emission with ultrahigh single-photon purity (99%) and enhanced emission stability approaching the shot-noise limit. Moreover, we demonstrate that the inherent optical tunability of single-walled carbon nanotubes, present inmore » their structural diversity, allows us to generate room-temperature single-photon emission spanning the entire telecom band. Furthermore, single-photon emission deep into the centre of the telecom C band (1.55 um) is achieved at the largest nanotube diameters we explore (0.936 nm).« less

  8. Accuracy of coregistration of single-photon emission CT with MR via a brain surface matching technique.

    PubMed

    Hogan, R E; Cook, M J; Kilpatrick, C J; Binns, D W; Desmond, P M; Morris, K

    1996-04-01

    We describe a technique of brain surface matching of single-photon emission CT and MR images in human subjects and document the accuracy of this technique with the use of fiduciary markers. This mismatch averaged 4.3 mm as measured by the fiduciary markers and 2.1 mm as measured by the root mean square distance.

  9. Scintimammography and single-photon emission computed tomography for postoperative image guidance for radiation treatment planning in breast cancer patients.

    PubMed

    Piperkova, E; Chavdarova, L; Garanina, Z; Gocheva, L; Parvanova, V; Tzonevska, A; Dimitrova, M

    2011-01-01

    To evaluate post-surgical tumor-metabolic regions outside of the computed tomography (CT)-defined volume for radiation therapy (RT) planning using functional imaging of scintimammography (SMG) ± single photon emission computerized tomography (SPECT) in breast cancer (BC) patients. 62 operated high-risk BC females, mean age 50.45 years, underwent SMG±SPECT before RT planning. Twenty-one and twelve patients with stage I and IIa respectively had lumpectomy (LT) with axillary lymph node dissection (ALND), and modified radical mastectomy (Patay) + ALND was realized in 29 stage IIb-III patients. All SMG images, positive for viable tumor tissue (VTT) or metastatically involved lymph nodes (LNs) were verified cytologically/ histologically. Three early planar and delayed images were acquired after i.v. administration of 550-740 MBq 99mTc- MIBI or 99mTc-TF. Uptake values (UV) > 1.65 revealed VTT. Data in 49 (79%) of 62 patients were characterized as true-negative (TN; UV<1.35). In 13 (21%) patients SMG visualized 22 true-positive (TP) malignant lesions: 2 residual VTT in scars, 1 newly defined BC in the contralateral breast and 18 regional LN metastases (6 axillary, 6 parasternal, 1 sub- and 5 supraclavicular). All 22 TP VTT lesions were imaged by scintigraphy using different tumor-seeking radiopharmaceuticals: 99mTc-MIBI - 17 (77%) and 99mTc- TF - 5 (23%) of the TP lesions. One false-positive (FP) (inflammation: UV>1.65) and one false-negative (FN) (UV<1.35) foci were found. Applying SMG±SPECT for BC restaging after surgery, the RT volume was changed in 13 of 62 (21%) patients. SMG is a reliable imaging method for evaluating residual VTT, LN metastases or altered biological activity in the scars after BC surgery and could modify the irradiated volume, optimizing the therapeutic effect and minimizing RT side effects.

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

    PubMed

    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.

  11. Image-Guided Drug Delivery with Single-Photon Emission Computed Tomography: A Review of Literature

    PubMed Central

    Chakravarty, Rubel; Hong, Hao; Cai, Weibo

    2014-01-01

    Tremendous resources are being invested all over the world for prevention, diagnosis, and treatment of various types of cancer. Successful cancer management depends on accurate diagnosis of the disease along with precise therapeutic protocol. The conventional systemic drug delivery approaches generally cannot completely remove the competent cancer cells without surpassing the toxicity limits to normal tissues. Therefore, development of efficient drug delivery systems holds prime importance in medicine and healthcare. Also, molecular imaging can play an increasingly important and revolutionizing role in disease management. Synergistic use of molecular imaging and targeted drug delivery approaches provides unique opportunities in a relatively new area called `image-guided drug delivery' (IGDD). Single-photon emission computed tomography (SPECT) is the most widely used nuclear imaging modality in clinical context and is increasingly being used to guide targeted therapeutics. The innovations in material science have fueled the development of efficient drug carriers based on, polymers, liposomes, micelles, dendrimers, microparticles, nanoparticles, etc. Efficient utilization of these drug carriers along with SPECT imaging technology have the potential to transform patient care by personalizing therapy to the individual patient, lessening the invasiveness of conventional treatment procedures and rapidly monitoring the therapeutic efficacy. SPECT-IGDD is not only effective for treatment of cancer but might also find utility in management of several other diseases. Herein, we provide a concise overview of the latest advances in SPECT-IGDD procedures and discuss the challenges and opportunities for advancement of the field. PMID:25182469

  12. On-chip time resolved detection of quantum dot emission using integrated superconducting single photon detectors

    PubMed Central

    Reithmaier, G.; Lichtmannecker, S.; Reichert, T.; Hasch, P.; Müller, K.; Bichler, M.; Gross, R.; Finley, J. J.

    2013-01-01

    We report the routing of quantum light emitted by self-assembled InGaAs quantum dots (QDs) into the optical modes of a GaAs ridge waveguide and its efficient detection on-chip via evanescent coupling to NbN superconducting nanowire single photon detectors (SSPDs). The waveguide coupled SSPDs primarily detect QD luminescence, with scattered photons from the excitation laser onto the proximal detector being negligible by comparison. The SSPD detection efficiency from the evanescently coupled waveguide modes is shown to be two orders of magnitude larger when compared with operation under normal incidence illumination, due to the much longer optical interaction length. Furthermore, in-situ time resolved measurements performed using the integrated detector show an average QD spontaneous emission lifetime of 0.95 ns, measured with a timing jitter of only 72 ps. The performance metrics of the SSPD integrated directly onto GaAs nano-photonic hardware confirms the strong potential for on-chip few-photon quantum optics using such semiconductor-superconductor hybrid systems. PMID:23712624

  13. Comparison of Ga-67 planar imaging and single photon emission computed tomography in malignant chest disease

    SciTech Connect

    Tumeh, S.S.; Rosenthal, D.; Kaplan, W.D.; English, R.E.; Holman, B.L.

    1985-05-01

    To determine the value of Ga-67 single photon emission computed tomography (SPECT) in patients (pts) with malignant chest disease, the authors compared Ga-67 planar scans (ps) and SPECT with the medical records in twenty-five consecutive patients. Twenty-three examinations were performed on 17 pts with Hodgkin's disease (HD) and three pts with non-Hodgkin's lymphoma. Five examinations were performed on 5 pts with bronchogenic carcinoma (BC). The two modalities were evaluated for (1) presence or absence of disease, (2) number of foci of abnormal uptake and (3) extent of disease. In pts with lymphoma, SPECT defined the extent of disease better than planar imaging in eight examinations; it demonstrated para-cardial involvement in one pt, separated hilar from mediastinal disease in 4, and demonstrated posterior mediastinal disease in 3. SPECT clarified suspicious foci on planar images in seven examinations, correctly ruled out disease in two pts with equivocal planar images and did not exchange planar image findings in six examinations. In pts with bronchogenic carcinoma, both medalities correctly ruled out mediastinal involvement in three pts. SPECT detected mediastinal lymph node involvement in one pt with equivocal planar images. Both SPECT and planar imaging missed direct tumor extension to the mediastinum in one pt. They conclude that Ga-67 with SPECT is better than planar images for staging of chest lymphoma and BC. Since it defines different lymph node groups it carries a good potential for staging as well as follow up of those pts.

  14. Single photon emission computed tomography: An alternative imaging modality in left ventricular evaluation

    PubMed Central

    Yalçin, Hulya; Maza, Sofiane; Yalçin, Fatih

    2008-01-01

    Various diagnostic imaging modalities have been used for quantitative left ventricular (LV) parameters. Because of the suboptimal value of the most widely used technology, two-dimensional (2D) echocardiography, 3D ultrasonographic imaging has improved accuracy for LV volume and function. Single photon emission computed tomography (SPECT) is another diagnostic method where LV volumetric and functional parameters can be accurately provided by gated myocardial perfusion tomographic slices. First pass radionuclide venticulography is another imaging modality which has some practical limitations. Despite lower ejection fraction (EF) values compared with invasive approach, noninvasive techniques are accurate in determination of normal and depressed EF. Noninvasive techniques with 3D approach including gated SPECT are beneficial for not only global but also regional LV evaluation. It has been mentioned that the slight difference between echocardiography and SPECT could be caused by the diverse population studied. The results of diagnostic stress tests support that SPECT is feasible to use in evaluation of LV volume and functional analysis. Magnetic resonance imaging is an expensive modality to use routinely, but it preserves its importance in selected patients for providing precise LV geometric data. PMID:19183754

  15. Rapid calculation of detectability in Bayesian single photon emission computed tomography

    NASA Astrophysics Data System (ADS)

    Xing, Yuxiang; Hsiao, Ing-Tsung; Gindi, Gene

    2003-11-01

    We consider the calculation of lesion detectability using a mathematical model observer, the channelized Hotelling observer (CHO), in a signal-known-exactly/background-known-exactly detection task for single photon emission computed tomography (SPECT). We focus on SPECT images reconstructed with Bayesian maximum a posteriori methods. While model observers are designed to replace time-consuming studies using human observers, the calculation of CHO detectability is usually accomplished using a large number of sample images, which is still time consuming. We develop theoretical expressions for a measure of detectability, the signal-to-noise-ratio (SNR) of a CHO observer, that can be very rapidly evaluated. Key to our expressions are approximations to the reconstructed image covariance. In these approximations, we use methods developed in the PET literature, but modify them to reflect the different nature of attenuation and distance-dependent blur in SPECT. We validate our expressions with Monte Carlo methods. We show that reasonably accurate estimates of the SNR can be obtained at a computational expense equivalent to approximately two projection operations, and that evaluating SNR for subsequent lesion locations requires negligible additional computation.

  16. Advances in Pinhole and Multi-Pinhole Collimators for Single Photon Emission Computed Tomography Imaging

    PubMed Central

    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

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

    PubMed

    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.

  18. Scintigraphic appearance of focal fatty infiltration of the liver using single-photon emission computed tomography

    SciTech Connect

    Kudo, M.; Hirasa, M.; Ibuki, Y.; Takakuwa, H.; Fujimi, K.; Veda, S.; Tomita, S.; Komori, H.; Todo, A.; Kitaura, Y.

    1984-01-01

    Fatty infiltration of the liver had been considered to assume a uniform distribution until quite recently. However, the development of X-ray computed tomography (XCT) and the ultrasound (US) has proven that fatty infiltration of the liver may sometimes assume a nonuniform distribution (focal fatty infiltration (FFI)). This investigation was undertaken to evaluate the scintigraphic appearance of FFI using single-photon emission computed tomography (SPECT) with a GE Maxicamera 400T. Radionuclide images including SPECT were evaluated in 12 cases with FFI which were diagnosed by XCT and US. Most of them were histrogically confirmed to be positive fatty infiltration in the liver. The results were as follows. The fatty infiltrated area was visualized as a hot spot in one case, a defect in 2 cases, a low uptake in one case and a normal uptake in 8 cases. Radionuclide imaging of FFI shows a large variety of findings and it suggests that Kupffer cell function varies with the causes or stage of fatty infiltration. And one can understand the pathological state of FFI from a viewpoint of Kupffer cell function only by radionuclide imaging including SPECT, which is very useful to compare the images with XCT images.

  19. Single photon emission computed tomograms of the liver: normal vascular intrahepatic structures.

    PubMed

    Pettigrew, R I; Witztum, K F; Perkins, G C; Johnson, M L; Burks, R N; Verba, J W; Halpern, S E

    1984-01-01

    Because of the high target-to-background contrast obtained with single photon emission computed tomography (SPECT), normal intrahepatic vessels approximately 2 cm in diameter may appear as distinct focal defects in tomographic sections throughout the liver even though normal vessels rarely cause such defects on planar images. To assess this problem, five subjects without evidence of liver disease underwent tomography of the liver with Tc-99m sulfur colloid (TSC) and on a separate occasion tomography of the intrahepatic blood pool with Tc-99m autologous red blood cells (RBC). In each case, well demarcated defects were obvious in contiguous TSC liver tomograms in various planes. Direct comparison with RBC tomograms showed that all of these defects corresponded to intrahepatic veins, typically the right portal vein, its posterior branch, and the left portal vein. Knowledge of the intrahepatic vascular anatomy in a variety of tomographic planes, with examination of each defect in multiple orthogonal planes is necessary to avoid false positive interpretations. In some instances a study with RBC may also be required for more conclusive evaluation of defects seen on TSC liver tomograms.

  20. Design of a serotonin 4 receptor radiotracer with decreased lipophilicity for single photon emission computed tomography.

    PubMed

    Fresneau, Nathalie; Dumas, Noé; Tournier, Benjamin B; Fossey, Christine; Ballandonne, Céline; Lesnard, Aurélien; Millet, Philippe; Charnay, Yves; Cailly, Thomas; Bouillon, Jean-Philippe; Fabis, Frédéric

    2015-04-13

    With the aim to develop a suitable radiotracer for the brain imaging of the serotonin 4 receptor subtype (5-HT4R) using single photon emission computed tomography (SPECT), we synthesized and evaluated a library of di- and triazaphenanthridines with lipophilicity values which were in the range expected to favour brain penetration, and which demonstrated specific binding to the target of interest. Adding additional nitrogen atoms to previously described phenanthridine ligands exhibiting a high unspecific binding, we were able to design a radioiodinated compound [(125)I]14. This compound exhibited a binding affinity value of 0.094 nM toward human 5-HT4R and a high selectivity over other serotonin receptor subtypes (5-HTR). In vivo SPECT imaging studies and competition experiments demonstrated that the decreased lipophilicity (in comparison with our previously reported compounds 4 and 5) allowed a more specific labelling of the 5-HT4R brain-containing regions. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  1. Periprosthetic bone turnover after primary total hip arthroplasty measured by single-photon emission computed tomography.

    PubMed

    Venesmaa, P; Vanninen, E; Miettinen, H; Kröger, H

    2012-01-01

    Alterations in periprosthetic bone are common sequlae of prosthetic implants.This prospective 3-year study was performed to follow regional periprosthetic bone turnover after uncomplicated total hip arthroplasty (THA) using single-photon emission computed tomography (SPECT). Eighteen patients (nine men, nine women: mean age 61 years, range from 50 to 73 years) with primary hip osteoarthritis underwent either uncemented or cemented THA. The SPECT measurements were taken 6, 12, and 36 months after THA. Bone mineral density (BMD) measurements were performed on the patients during follow-up. The mean SPECT uptake ratios decreased significantly in the regions of interest (ROIs) during follow-up compared to baseline value, in the trochanter major (p = 0.006), the trochanter minor (p = 0.009) and the total area (p = 0.018). Despite these decreases the uptake ratios in the medial cortex (p = 0.014), tip (p = 0.002) and total area (p = 0.016) remained significantly higher in the operated side than in the contralateral side (non-operated) 3 years after THA. Changes in bone turnover in the vicinity of the implant did not correlate with changes in periprosthetic BMD. Local periprosthetic bone turnover decreased slowly after THA and did not recover to the level typical of non-operated hips. This led us to suggest that bone turnover around the femoral implants remains increased more than 3 years after THA even if there are no signs of failure of the prosthesis.

  2. Cardiac single-photon emission-computed tomography using combinedcone-beam/fan-beam collimation

    SciTech Connect

    Gullberg, Grant T.; Zeng, Gengsheng L.

    2004-12-03

    The objective of this work is to increase system sensitivity in cardiac single-photon emission-computed tomography (SPECT) studies without increasing patient imaging time. For imaging the heart, convergent collimation offers the potential of increased sensitivity over that of parallel-hole collimation. However, if a cone-beam collimated gamma camera is rotated in a planar orbit, the projection data obtained are not complete. Two cone-beam collimators and one fan-beam collimator are used with a three-detector SPECT system. The combined cone-beam/fan-beam collimation provides a complete set of data for image reconstruction. The imaging geometry is evaluated using data acquired from phantom and patient studies. For the Jaszazck cardiac torso phantom experiment, the combined cone-beam/fan-beam collimation provided 1.7 times greater sensitivity than standard parallel-hole collimation (low-energy high-resolution collimators). Also, phantom and patient comparison studies showed improved image quality. The combined cone-beam/fan-beam imaging geometry with appropriate weighting of the two data sets provides improved system sensitivity while measuring sufficient data for artifact free cardiac images.

  3. On-chip time resolved detection of quantum dot emission using integrated superconducting single photon detectors.

    PubMed

    Reithmaier, G; Lichtmannecker, S; Reichert, T; Hasch, P; Müller, K; Bichler, M; Gross, R; Finley, J J

    2013-01-01

    We report the routing of quantum light emitted by self-assembled InGaAs quantum dots (QDs) into the optical modes of a GaAs ridge waveguide and its efficient detection on-chip via evanescent coupling to NbN superconducting nanowire single photon detectors (SSPDs). The waveguide coupled SSPDs primarily detect QD luminescence, with scattered photons from the excitation laser onto the proximal detector being negligible by comparison. The SSPD detection efficiency from the evanescently coupled waveguide modes is shown to be two orders of magnitude larger when compared with operation under normal incidence illumination, due to the much longer optical interaction length. Furthermore, in-situ time resolved measurements performed using the integrated detector show an average QD spontaneous emission lifetime of 0.95 ns, measured with a timing jitter of only 72 ps. The performance metrics of the SSPD integrated directly onto GaAs nano-photonic hardware confirms the strong potential for on-chip few-photon quantum optics using such semiconductor-superconductor hybrid systems.

  4. Quantitation of postexercise lung thallium-201 uptake during single photon emission computed tomography

    SciTech Connect

    Kahn, J.K.; Carry, M.M.; McGhie, I.; Pippin, J.J.; Akers, M.S.; Corbett, J.R.

    1989-03-01

    To test the hypothesis that analysis of lung thallium uptake measured during single photon emission computed tomography (SPECT) yields supplementary clinical information as reported for planar imaging, quantitative analysis of lung thallium uptake following maximal exercise was performed in 40 clinically normal subjects (Group 1) and 15 angiographically normal subjects (Group 2). Lung thallium uptake was measured from anterior projection images using a ratio of heart-to-lung activities. Seventy subjects with coronary artery disease (CAD) (Group 3) determined by angiography (greater than or equal to 70% luminal stenosis) underwent thallium perfusion SPECT. Thirty-nine percent of these subjects had multivessel and 61% had single vessel CAD. Lung thallium uptake was elevated in 47 of 70 (67%) Group 3 subjects. Group 3 subjects with elevated lung thallium uptake did not differ from Group 3 subjects with normal lung thallium uptake with respect to extent or distribution of coronary artery disease, left ventricular function, or severity of myocardial ischemia as determined by exercise and redistribution thallium SPECT. Thus, the measurement of thallium lung uptake from anterior projection images obtained during SPECT frequently identifies patients with CAD, but it may not provide supplementary information regarding the extent of myocardial ischemia or ventricular dysfunction.

  5. An audit of manufacturers' implementation of reconstruction filters in single-photon emission computed tomography.

    PubMed

    Lawson, Richard S; White, Duncan; Cade, Sarah C; Hall, David O; Kenny, Bob; Knight, Andy; Livieratos, Lefteris; Nijran, Kuldip

    2013-08-01

    The Nuclear Medicine Software Quality Group of the Institute of Physics and Engineering in Medicine has conducted an audit to compare the ways in which different manufacturers implement the filters used in single-photon emission computed tomography. The aim of the audit was to identify differences between manufacturers' implementations of the same filter and to find means for converting parameters between systems. Computer-generated data representing projection images of an ideal test object were processed using seven different commercial nuclear medicine systems. Images were reconstructed using filtered back projection and a Butter worth filter with three different cutoff frequencies and three different orders. The audit found large variations between the frequency-response curves of what were ostensibly the same filters on different systems. The differences were greater than could be explained simply by different Butter worth formulae. Measured cutoff frequencies varied between 40 and 180% of that expected. There was also occasional confusion with respect to frequency units. The audit concluded that the practical implementation of filtering, such as the size of the kernel, has a profound effect on the results, producing large differences between systems. Nevertheless, this work shows how users can quantify the frequency response of their own systems so that it will be possible to compare two systems in order to find filter parameters on each that produce equivalent results. These findings will also make it easier for users to replicate filters similar to other published results, even if they are using a different computer system.

  6. Fragile X syndrome and cerebral perfusion abnormalities: single-photon emission computed tomographic study.

    PubMed

    Kabakus, Nimet; Aydin, Mustafa; Akin, Haluk; Balci, Tansel Ansal; Kurt, Abdullah; Kekilli, Ersoy

    2006-12-01

    Fragile X syndrome is an inherited disorder caused by a defective gene on the X chromosome. It is associated with developmental or behavioral symptoms and various degrees of mental retardation. Morphologic abnormalities and altered perfusion of various brain areas can underlie these functional disturbances. The aim of this study was to investigate the cerebral perfusion state in patients with fragile X syndrome using single-photon emission computed tomography (SPECT). Structural and functional assessment was also performed by magnetic resonance imaging (MRI) and electroencephalography (EEG). Eight boys with cytogenetically confirmed fragile X syndrome (mean age 8.8 +/- 4.4 years, range 5-18 years), were included. All patients had mental retardation, with a mean IQ of 58.9 +/- 8.8 (range 40-68), and additional neurobehavioral symptoms. SPECT revealed cerebral perfusion abnormalities in six patients (75%), most commonly in the frontoparietotemporal area and prominent in the right hemisphere. The SPECT and EEG findings were concordant: hypoperfused areas in SPECT corresponded to regions of persistent slow-wave paroxysms on EEG. On the other hand, cranial MRI was abnormal qualitatively only in two patients (25%) showing cerebellar and vermal hypoplasia and cerebral hemispheric asymmetry. Our results indicate that cerebral perfusion abnormalities, which are correlated with electrophysiologic findings but not necessarily with anatomic abnormalities, can underlie the pathogenesis of the clinical findings observed in fragile X syndrome.

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

    SciTech Connect

    Loutfi, I.; Frackowiak, R.S.; Myers, M.J.; Lavender, J.P.

    1987-01-01

    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.

  8. [Visualized study on acupuncture treatment of children autism using single photon emission computed tomography].

    PubMed

    Jia, Shao-Wei; Sun, Tao-Tao; Fan, Rong

    2008-10-01

    To provide the molecular iconographic evidence for acupuncture treatment of children autism (CA). Electric acupuncture (EA) was applied on acupoints of bilateral Hegu (LI4), Quchi (LI11), Zusanli (ST36) and Sanyinjiao (SP6) in 34 CA patients' with ABC scale > 57 scores. Using SIEMENS ECAM / ICON double head system, single photon emission computed tomography (SPECT) brain perfusion imaging were performed before and during EA with 99mTc-ECD. Then SPECT images were analyzed visually and quantitatively. Visual analysis showed that 114 foci of low cerebral perfusion and function were found in 34 CA patients before EA, 28 cases (82.35%) of them with abnormalities in left (or both) front lobes, left Broca area and left Wernicke area. During EA, the affected areas improved to different extent. Quantitative analysis showed that significant difference existed between pre-EA focal Ff and mirror-side Ff, pre-EA Ff and mid-EA Fe, focal BFCR% and mirror-side BFCR % (all P < 0.01). The improving analysis of cerebral perfusion and function showed that the efficacy of EA was 78.95%. Acupuncture was proved preliminarily effective in treating children autism.

  9. [Cost-effectiveness of stress-only myocardial perfusion single photon emission computed tomography (SPECT) imaging].

    PubMed

    Vallejo, Enrique; Acevedo, César; Varela, Samuel; Alburez, José Carlos; Bialostozky, David

    2012-01-01

    Single photon emission computed tomography (SPECT) myocardial perfusion imaging is widely used for diagnosing coronary artery disease (CAD). However, SPECT costs, imaging time, and radiation exposure, limit SPECT indications. Determine whether a stress-only SPECT imaging would be enough to obtain a diagnosis of CAD improving nuclear laboratory efficiency. 122 patients with unknown CAD were evaluated with stress-only SPECT imaging. In order to evaluate diagnostic accuracy and the prognostic value of the stress-only protocol, patients with abnormal SPECT underwent invasive angiography and patients with normal SPECT were followed-up during 3 years. Diagnosis time, SPECT cost, and radiopharmaceutical dosage were significantly lower as compared with the conventional SPECT imaging protocol (30, 40 and 55%, respectively). Diagnostic accuracy and cardiac prognosis information were comparable to those obtained with the conventional imaging protocol (positive predictive value for CAD of 85% and negative predictive value for cardiac events of 97%). In patients with intermediate risk for CAD, stress-only SPECT imaging will significantly improve nuclear laboratory efficiency, and with similar accuracy than that the one obtained with the conventional protocol.

  10. Quantitative and Qualitative Imaging in Single Photon Emission Tomography for Nuclear Medicine Applications.

    NASA Astrophysics Data System (ADS)

    Masoomi, Mojtaba (Arash).

    Available from UMI in association with The British Library. An important goal of single photon emission tomography (SPECT) is the determination of absolute regional radionuclide concentration as a function of time. Quantitative and qualitative studies of SPECT with regard to clinical application is the object of this work. Three basic approaches for image reconstruction and factors which affect the choice of a reconstruction algorithm have been reviewed, discussed and the reconstruction techniques, GRADY and CBP evaluated, based on computer modelling. A sophisticated package of computational subroutines, RECLBL, for image reconstruction and for generation of phantoms, which was fully implemented on PRIME was used throughout this study. Two different systems, a rotating gamma-camera and a prototype scanning-rig have been used to carry out tomography experiments with different phantoms in emission and transmission mode. Performance assessment and reproducibility of the gamma-camera was tested prior to the experimental work. SPECT studies are generally hampered for a number of reasons, the most severe being attenuation and scattering. The effect of scattered photons on image quality was discussed, three distinct techniques were utilised to correct the images and results were compared. Determination of the depth of the source, Am-241 and Tc-99m in the attenuating media, water and TEMEX by analysing the spectroscopic data base on the SPR and spatial resolution was studied, results revealed that both techniques had the same range of depth sensitivity. A method of simultaneous emission and transmission tomography was developed to correct the images for attenuation. The reproducibility of the technique was examined. Results showed that the technique is able to present a promising and a practical approach to more accurate quantitative SPECT imaging. A procedure to evaluate images, under certain conditions has been defined, its properties were evaluated using computer

  11. Controlled single-photon emission from a single trapped two-level atom.

    PubMed

    Darquié, B; Jones, M P A; Dingjan, J; Beugnon, J; Bergamini, S; Sortais, Y; Messin, G; Browaeys, A; Grangier, P

    2005-07-15

    By illuminating an individual rubidium atom stored in a tight optical tweezer with short resonant light pulses, we created an efficient triggered source of single photons with a well-defined polarization. The measured intensity correlation of the emitted light pulses exhibits almost perfect antibunching. Such a source of high-rate, fully controlled single-photon pulses has many potential applications for quantum information processing.

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

    PubMed Central

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

    2015-01-01

    Sources of single photons are key elements for applications in quantum information science. Among the different sources available, semiconductor quantum dots excel with their integrability in semiconductor on-chip solutions and the potential that photon emission can be triggered on demand. Usually, the photon is emitted from a single-exciton ground state. Polarization of the photon and time of emission are either probabilistic or pre-determined by electronic properties of the system. Here, we study the direct two-photon emission from the biexciton. The two-photon emission is enabled by a laser pulse driving the system into a virtual state inside the band gap. From this intermediate state, the single photon of interest is then spontaneously emitted. We show that emission through this higher-order transition provides a versatile approach to generate a single photon. Through the driving laser pulse, polarization state, frequency and emission time of the photon can be controlled on-the-fly. PMID:26436776

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

    PubMed Central

    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

  14. Single-photon emission computed tomography/computed tomography in brain tumors.

    PubMed

    Schillaci, Orazio; Filippi, Luca; Manni, Carlo; Santoni, Riccardo

    2007-01-01

    Anatomic imaging procedures (computed tomography [CT] and magnetic resonance imaging [MRI]) have become essential tools for brain tumor assessment. Functional images (positron emission tomography [PET] and single-photon emission computed tomography [SPECT]) can provide additional information useful during the diagnostic workup to determine the degree of malignancy and as a substitute or guide for biopsy. After surgery and/or radiotherapy, nuclear medicine examinations are essential to assess persistence of tumor, to differentiate recurrence from radiation necrosis and gliosis, and to monitor the disease. The combination of functional images with anatomic ones is of the utmost importance for a full evaluation of these patients, which can be obtained by means of imaging fusion. Despite the fast-growing diffusion of PET, in most cases of brain tumors, SPECT studies are adequate and provide results that parallel those obtained with PET. The main limitation of SPECT imaging with brain tumor-seeking radiopharmaceuticals is the lack of precise anatomic details; this drawback is overcome by the fusion with morphological studies that provide an anatomic map to scintigraphic data. In the past, software-based fusion of independently performed SPECT and CT or MRI demonstrated usefulness for brain tumor assessment, but this process is often time consuming and not practical for everyday nuclear medicine studies. The recent development of dual-modality integrated imaging systems, which allow the acquisition of SPECT and CT images in the same scanning session, and their co-registration by means of the hardware, has facilitated this process. In SPECT studies of brain tumors with various radiopharmaceuticals, fused images are helpful in providing the precise localization of neoplastic lesions, and in excluding the disease in sites of physiologic tracer uptake. This information is useful for optimizing diagnosis, therapy monitoring, and radiotherapy treatment planning, with a

  15. Abnormal 201Tl myocardial single photon emission computed tomography in energetic male patients with myocardial bridge.

    PubMed

    Huang, W S; Chang, H D; Yang, S P; Tsao, T P; Cheng, C Y; Cherng, S C

    2002-11-01

    Myocardial bridge is a relatively benign condition where a major coronary artery is bridged by a band of muscle and narrows during systole, particularly during rapid heart rates. Its clinical presentation and electrocardiogram (ECG) changes overlap with that of coronary artery disease. 201Tl myocardial perfusion imaging is thus frequently prescribed for further evaluation. This retrospective study was carried out to determine the 201Tl image patterns in patients with myocardial bridge. A total of 17 male patients (aged from 30 to 63 years) who had a positive exercise ECG and angiographic evidence of myocardial bridge in the mid-third of the left anterior descending coronary artery were recruited. Most of them were robust and received routine physical check-ups. They had no known heart disease or medication that affected cardiac function. The patients' clinical presentations, echocardiograph and exercise ECG findings were analysed. 201Tl single photon emission computed tomography (SPECT) was performed by intravenous injection of 201Tl (111 MBq) immediately following stress (treadmill or dipyridamole induced) and 4 h after stress, using a fixed, right angle camera equipped with a low energy, general purpose collimator. The images were interpreted independently by two experienced nuclear medicine physicians. Nine of the 17 patients had anterior chest pain during exercise. All patients had an abnormal ECG during exercise, including ST-T wave depression in leads II, III and aVF, and v4-6. Except for eight patients revealing reversible perfusion defect (R), 16 of the 17 patients also exhibited a partial reversible perfusion defect (PR) or a significant reverse redistribution (RR) scan pattern in the anterior or inferior walls of the left ventricle. Myocardial bridge should be taken into consideration in energetic male patients who had abnormal exercise ECGs and the corresponding patterns of Tl SPECT abnormalities including R, PR and RR.

  16. Incremental prognostic value of coronary flow reserve assessed with single-photon emission computed tomography.

    PubMed

    Daniele, Stefania; Nappi, Carmela; Acampa, Wanda; Storto, Giovanni; Pellegrino, Teresa; Ricci, Francesca; Xhoxhi, Evgjeni; Porcaro, Francesco; Petretta, Mario; Cuocolo, Alberto

    2011-08-01

    We assessed the prognostic value of coronary flow reserve (CFR) estimated by single-photon emission computed tomography (SPECT) in patients with suspected myocardial ischemia. Myocardial perfusion and CFR were assessed in 106 patients using dipyridamole/rest Tc-99m sestamibi SPECT and follow-up was obtained in 103 (97%) patients. Four early revascularized patients were excluded and 99 were assigned to normal (summed stress score <3) vs abnormal myocardial perfusion and to normal (≥2.0) vs abnormal CFR. During the follow-up (5.8 ± 2.1 years), 28 patients experienced a cardiac event (cardiac death, nonfatal myocardial infarction, and late revascularization). Abnormal perfusion (P < .01) and abnormal CFR (P < .05) were independent predictors of cardiac events at Cox proportional hazard regression analysis. Also in patients with normal perfusion, abnormal CFR was associated with a higher annual event rate compared with normal CFR (5.2% vs 0.7%; P < .05). CFR data improved the prognostic power of the model including clinical and myocardial perfusion data increasing the global chi-square from 18.6 to 22.8 (P < .05). Finally, at parametric survival analysis, in patients with normal perfusion the time to achieve ≥2% risk of events was >60 months in those with normal and <12 months in those with abnormal CFR. Myocardial perfusion findings and CFR at SPECT imaging are both independent predictors of cardiac events. Estimated CFR provides incremental prognostic information over those obtained from clinical and myocardial perfusion data, particularly in patients with normal perfusion findings.

  17. UK audit of single photon emission computed tomography reconstruction software using software generated phantoms.

    PubMed

    Jarritt, P H; Whalley, D R; Skrypniuk, J V; Houston, A S; Fleming, J S; Cosgriff, P S

    2002-05-01

    The purpose of this study was to undertake an audit of the quantitative characteristics of single photon emission computed tomography software using projection data from an analytically generated software phantom and a measured line source. The phantom consisted of three structures. A uniformly filled cylinder, a series of cylindrical rods of various diameters in a background activity with a rod to background ratio of 2:1 and lastly, a set of three concentric rings of activity in the ratio 1:0:1. The phantom contained no added statistical noise. No attenuation was imposed on the data. The phantom was generated analytically and projections were distributed at six different count densities. A single set of projections from a thin line source was also distributed. These data were distributed to centres throughout the UK. Centres were asked to reconstruct the data using a 'ramp only' reconstruction with no additional smoothing function applied. Data were requested for mean and standard deviation in the uniform cylinder, the maximum counts for each cylindrical rod and the mean counts in regions placed within the concentric rings. For the measured line source, centres were asked to measure the full width at half maximum and peak pixel counts for a profile through the reconstructed line. Results from 115 systems were obtained from 100 centres throughout the UK. These provided data from 12 software providers, 11 of these being commercial companies. Data were compared with the known input values and histograms of the distribution of results obtained. Significant differences in quantitative parameters were noted for the different input count densities as well as between suppliers and revisions of software from single suppliers.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Dynamic single photon emission computed tomography—basic principles and cardiac applications

    PubMed Central

    Gullberg, Grant T; Reutter, Bryan W; Sitek, Arkadiusz; Maltz, Jonathan S; Budinger, Thomas F

    2011-01-01

    The very nature of nuclear medicine, the visual representation of injected radiopharmaceuticals, implies imaging of dynamic processes such as the uptake and wash-out of radiotracers from body organs. For years, nuclear medicine has been touted as the modality of choice for evaluating function in health and disease. This evaluation is greatly enhanced using single photon emission computed tomography (SPECT), which permits three-dimensional (3D) visualization of tracer distributions in the body. However, to fully realize the potential of the technique requires the imaging of in vivo dynamic processes of flow and metabolism. Tissue motion and deformation must also be addressed. Absolute quantification of these dynamic processes in the body has the potential to improve diagnosis. This paper presents a review of advancements toward the realization of the potential of dynamic SPECT imaging and a brief history of the development of the instrumentation. A major portion of the paper is devoted to the review of special data processing methods that have been developed for extracting kinetics from dynamic cardiac SPECT data acquired using rotating detector heads that move as radiopharmaceuticals exchange between biological compartments. Recent developments in multi-resolution spatiotemporal methods enable one to estimate kinetic parameters of compartment models of dynamic processes using data acquired from a single camera head with slow gantry rotation. The estimation of kinetic parameters directly from projection measurements improves bias and variance over the conventional method of first reconstructing 3D dynamic images, generating time–activity curves from selected regions of interest and then estimating the kinetic parameters from the generated time–activity curves. Although the potential applications of SPECT for imaging dynamic processes have not been fully realized in the clinic, it is hoped that this review illuminates the potential of SPECT for dynamic imaging

  1. TOPICAL REVIEW: Dynamic single photon emission computed tomography—basic principles and cardiac applications

    NASA Astrophysics Data System (ADS)

    Gullberg, Grant T.; Reutter, Bryan W.; Sitek, Arkadiusz; Maltz, Jonathan S.; Budinger, Thomas F.

    2010-10-01

    The very nature of nuclear medicine, the visual representation of injected radiopharmaceuticals, implies imaging of dynamic processes such as the uptake and wash-out of radiotracers from body organs. For years, nuclear medicine has been touted as the modality of choice for evaluating function in health and disease. This evaluation is greatly enhanced using single photon emission computed tomography (SPECT), which permits three-dimensional (3D) visualization of tracer distributions in the body. However, to fully realize the potential of the technique requires the imaging of in vivo dynamic processes of flow and metabolism. Tissue motion and deformation must also be addressed. Absolute quantification of these dynamic processes in the body has the potential to improve diagnosis. This paper presents a review of advancements toward the realization of the potential of dynamic SPECT imaging and a brief history of the development of the instrumentation. A major portion of the paper is devoted to the review of special data processing methods that have been developed for extracting kinetics from dynamic cardiac SPECT data acquired using rotating detector heads that move as radiopharmaceuticals exchange between biological compartments. Recent developments in multi-resolution spatiotemporal methods enable one to estimate kinetic parameters of compartment models of dynamic processes using data acquired from a single camera head with slow gantry rotation. The estimation of kinetic parameters directly from projection measurements improves bias and variance over the conventional method of first reconstructing 3D dynamic images, generating time-activity curves from selected regions of interest and then estimating the kinetic parameters from the generated time-activity curves. Although the potential applications of SPECT for imaging dynamic processes have not been fully realized in the clinic, it is hoped that this review illuminates the potential of SPECT for dynamic imaging

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

    PubMed Central

    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 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. Prognostic value of single-photon emission tomography in acute ischaemic stroke.

    PubMed

    Weir, C J; Bolster, A A; Tytler, S; Murray, G D; Corrigall, R S; Adams, F G; Lees, K R

    1997-01-01

    Single-photon emission tomography (SPET) is widely used in the investigation of acute stroke. We investigated the relationship between SPET data and functional outcome in a large group of acute stroke patients. One hundred and eight patients underwent cerebral computed tomography (CT) and technetium-99m hexamethylpropylene amine oxime SPET after acute ischaemic stroke. We categorised the clinical presentation according to the Oxford classification of acute stroke. Outcome was measured 1 year after stroke using mortality and the Barthel Index for survivors. SPET scans were interpreted without reference to the clinical data using a semi-automatic technique. Three experienced observers determined the presence of luxury perfusion using suitably scaled SPET images in conjunction with the CT scan. Both SPET volume and severity of deficit were significantly negatively correlated with Barthel Index at 1 year (rs=-0.310, P<0.0001, and rs=-0.316, P<0.0001 respectively). In patients scanned with SPET within 16 h of stroke onset, the correlations were more strongly negative (rs=-0.606, P<0. 001, and rs=-0.492, P<0.005 respectively). Luxury perfusion was not associated (chi2=0.073, df=1, P=0.79) with good functional outcome (Barthel score >/=60). Stepwise logistic regression identified Oxford classification, total deficit volume and patient's age as significant predictors of functional outcome. Overall predictive accuracy was 72%. Predictive accuracy was better in patients who received SPET within 16 h of stroke onset. SPET provides useful information about the functional outcome of acute stroke at 1 year. However, the accuracy of prediction decreases the longer SPET is delayed. Prognostication using SPET in combination with clinical assessment and other investigations may also be considered.

  4. The Usefulness of Single-Photon Emission Computed Tomography in Defining Painful Upper Cervical Facet Arthropathy.

    PubMed

    Ravindra, Vijay M; Mazur, Marcus D; Bisson, Erica F; Barton, Craig; Shah, Lubdha M; Dailey, Andrew T

    2016-12-01

    Standard imaging techniques have low predictive value for identifying sources of neck pain. Single-photon emission computed tomography (SPECT) imaging in conjunction with computed tomography (CT) provides the sensitivity of bone scanning for areas of high metabolic activity with the sensitivity of CT for anatomic localization. We evaluated the usefulness of SPECT-CT imaging in identifying pain generators in upper cervical facet arthropathy. In a retrospective study, we reviewed 7 patients (mean age, 68.7 years) who underwent diagnostic SPECT-CT imaging for upper cervical neck pain at our institution from August 2011 to February 2015. We assessed SPECT-CT radiotracer uptake and postoperative neck disability index (NDI) and visual analog scale (VAS) scores. Mean preoperative NDI and VAS scores were 42% (range, 34%-72%) and 7/10 (range, 5-8), respectively. SPECT-CT showed increased radiotracer uptake and inflammation at the level of pain generation indicated by history and physical examination. Intraoperatively, all patients had corresponding facet hypertrophy with degeneration at the site of increased radiotracer uptake. The mean postoperative NDI and VAS scores at 9 months were 23% (0%-54%) and 2/10 (0-5), respectively, representing improvements of 20% (P = 0.025) and 4 (P = 0.0028), respectively. SPECT-CT imaging of the upper cervical spine is a potentially sensitive diagnostic test that can implicate pain generators with increased metabolic activity. We propose that SPECT-CT may be a useful adjunct in the workup for neck pain secondary to facet arthropathy that could obviate diagnostic injections. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement.

    PubMed

    Lee, Hyunjong; Kim, Ji Hyun; Kang, Yeon-Koo; Moon, Jae Hoon; So, Young; Lee, Won Woo

    2016-07-01

    Technetium pertechnetate (TcO4) is a radioactive tracer used to assess thyroid function by thyroid uptake system (TUS). However, the TUS often fails to deliver accurate measurements of the percent of thyroid uptake (%thyroid uptake) of TcO4. Here, we investigated the usefulness of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) after injection of TcO4 in detecting thyroid function abnormalities. We retrospectively reviewed data from 50 patients (male:female = 15:35; age, 46.2 ± 16.3 years; 17 Graves disease, 13 thyroiditis, and 20 euthyroid). All patients underwent TcO4 quantitative SPECT/CT (185 MBq = 5 mCi), which yielded %thyroid uptake and standardized uptake value (SUV). Twenty-one (10 Graves disease and 11 thyroiditis) of the 50 patients also underwent conventional %thyroid uptake measurements using a TUS. Quantitative SPECT/CT parameters (%thyroid uptake, SUVmean, and SUVmax) were the highest in Graves disease, second highest in euthyroid, and lowest in thyroiditis (P < 0.0001, Kruskal-Wallis test). TUS significantly overestimated the %thyroid uptake compared with SPECT/CT (P < 0.0001, paired t test) because other TcO4 sources in addition to thyroid, such as salivary glands and saliva, contributed to the %thyroid uptake result by TUS, whereas %thyroid uptake, SUVmean and SUVmax from the SPECT/CT were associated with the functional status of thyroid. Quantitative SPECT/CT is more accurate than conventional TUS for measuring TcO4 %thyroid uptake. Quantitative measurements using SPECT/CT may facilitate more accurate assessment of thyroid tracer uptake.

  6. Predicting exercise capacity after lobectomy by single photon emission computed tomography and computed tomography.

    PubMed

    Nagamatsu, Yoshinori; Sueyoshi, Susumu; Sasahara, Hiroko; Oka, Yousuke; Kumazoe, Hiroyuki; Mitsuoka, Masahiro; Akagi, Yoshito

    2016-09-01

    This study compared the prediction of postoperative exercise capacity by employing lung perfusion scintigraphy images obtained with single photon emission computed tomography together with computed tomography (SPECT/CT) versus the common method of counting subsegments (SC method). In 18 patients scheduled for lobectomy, predicted postoperative maximum oxygen uptake per kilogram body weight ([Formula: see text]) was calculated by the SPECT/CT and SC methods. Correlations were examined between the [Formula: see text] predicted by SPECT/CT or the SC method, and the actual [Formula: see text] measured at 2 weeks (mean 15.4 ± 1.5 days) and 1 month (mean 29.1 ± 0.75 days) after surgery to determine whether SPECT/CT was more accurate than SC for predicting postoperative exercise capacity. There was a significant positive correlation between the [Formula: see text] predicted by SPECT/CT and the actual value at 2 weeks (r = 0.802, p < 0.0001) or 1 month (r = 0.770, p < 0.0001). There was also a significant positive correlation between the [Formula: see text] predicted by SC and the actual value at 2 weeks (r = 0.785, p < 0.0001) or 1 month (r = 0.784, p < 0.0001). This study showed that both SPECT/CT and the SC method were useful for predicting postoperative [Formula: see text] in the clinical setting.

  7. Evaluation of Technetium-99m glucoheptonate single photon emission computed tomography for brain tumor grading

    PubMed Central

    Alam, Syed Shafiq; Junaid, Syed; Ahmed, Syed Mushtaq

    2016-01-01

    Background: This study is designed to appraise the diagnostic value of technetium-99m glucoheptonate (Tc-99m GHA) single photon emission computed tomography (SPECT) in brain tumor grading. Subjects and Methods: The study was performed on 30 patients referred from the Department of Neurosurgery, who were from both urban and rural areas. Data were collected through interview, history taking, and clinical examination followed by recording the desired parameters and finally imaging. The study subjects were divided into five groups: Controls (n = 4), low-grade tumors (n = 8), high-grade tumors (n = 8), metastases (n = 5), and nonneoplastic lesions (n = 5). This division was based on the World Health Organization (WHO) classification postclinico-histological diagnosis. Each of the subjects underwent contrast-enhanced computed tomography/contrast-enhanced magnetic resonance and Tc-99m GHA SPECT preoperatively. All were followed up postoperatively, and histopathological reports were regarded as the gold standard for tumor grading wherever available. Results: It was found that high-grade tumors (Grades III/IV and IV/IV according to the WHO classification) showed significantly higher tumor to normal (T/N) ratios as well as Tmax/N ratios when compared with low-grade tumors (Grades I/IV and II/IV), metastases or nonneoplastic lesions. Conclusions: In summary, the results of this study suggest that in situations where a preoperative grading of tumor is required Tc-99m GHA can be used in tumor grading and its use should be encouraged. Semi-quantitative analysis using both T/N as well as Tmax/N can be used in differentiating high-grade tumors from low-grade ones. PMID:27057217

  8. Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement

    PubMed Central

    Lee, Hyunjong; Kim, Ji Hyun; Kang, Yeon-koo; Moon, Jae Hoon; So, Young; Lee, Won Woo

    2016-01-01

    Abstract Objectives: Technetium pertechnetate (99mTcO4) is a radioactive tracer used to assess thyroid function by thyroid uptake system (TUS). However, the TUS often fails to deliver accurate measurements of the percent of thyroid uptake (%thyroid uptake) of 99mTcO4. Here, we investigated the usefulness of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) after injection of 99mTcO4 in detecting thyroid function abnormalities. Materials and methods: We retrospectively reviewed data from 50 patients (male:female = 15:35; age, 46.2 ± 16.3 years; 17 Graves disease, 13 thyroiditis, and 20 euthyroid). All patients underwent 99mTcO4 quantitative SPECT/CT (185 MBq = 5 mCi), which yielded %thyroid uptake and standardized uptake value (SUV). Twenty-one (10 Graves disease and 11 thyroiditis) of the 50 patients also underwent conventional %thyroid uptake measurements using a TUS. Results: Quantitative SPECT/CT parameters (%thyroid uptake, SUVmean, and SUVmax) were the highest in Graves disease, second highest in euthyroid, and lowest in thyroiditis (P < 0.0001, Kruskal–Wallis test). TUS significantly overestimated the %thyroid uptake compared with SPECT/CT (P < 0.0001, paired t test) because other 99mTcO4 sources in addition to thyroid, such as salivary glands and saliva, contributed to the %thyroid uptake result by TUS, whereas %thyroid uptake, SUVmean and SUVmax from the SPECT/CT were associated with the functional status of thyroid. Conclusions: Quantitative SPECT/CT is more accurate than conventional TUS for measuring 99mTcO4 %thyroid uptake. Quantitative measurements using SPECT/CT may facilitate more accurate assessment of thyroid tracer uptake. PMID:27399139

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

    NASA Astrophysics Data System (ADS)

    Faham, C. H.; Gehman, V. M.; Currie, A.; Dobi, A.; Sorensen, P.; Gaitskell, R. J.

    2015-09-01

    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 ~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. Two-color single-photon emission from InAs quantum dots: toward logic information management using quantum light.

    PubMed

    Rivas, David; Muñoz-Matutano, Guillermo; Canet-Ferrer, Josep; García-Calzada, Raúl; Trevisi, Giovanna; Seravalli, Luca; Frigeri, Paola; Martínez-Pastor, Juan P

    2014-02-12

    In this work, we propose the use of the Hanbury-Brown and Twiss interferometric technique and a switchable two-color excitation method for evaluating the exciton and noncorrelated electron-hole dynamics associated with single photon emission from indium arsenide (InAs) self-assembled quantum dots (QDs). Using a microstate master equation model we demonstrate that our single QDs are described by nonlinear exciton dynamics. The simultaneous detection of two-color, single photon emission from InAs QDs using these nonlinear dynamics was used to design a NOT AND logic transference function. This computational functionality combines the advantages of working with light/photons as input/output device parameters (all-optical system) and that of a nanodevice (QD size of ∼ 20 nm) while also providing high optical sensitivity (ultralow optical power operational requirements). These system features represent an important and interesting step toward the development of new prototypes for the incoming quantum information technologies.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  13. [Analysis of single-photon emission computed tomography in patients with hypertensive encephalopathy complicated with previous hypertensive crisis].

    PubMed

    Kustkova, H S

    2012-01-01

    In cerebrovascular diseases pefuzionnaya single photon emission computed tomography with lipophilic amines used for the diagnosis of functional disorders of cerebral blood flow. Quantitative calculations helps clarify the nature of vascular disease and clarify the adequacy and effectiveness of the treatment. In this modern program for SPECT ensure conduct not only as to the calculation of blood flow, but also make it possible to compute also the absolute values of cerebral blood flow.

  14. Single photon emission computed tomography/computed tomography for malignant otitis externa: lesion not shown on planar image.

    PubMed

    Chen, Yu-Hung; Hsieh, Hung-Jen

    2013-01-01

    Malignant otitis externa is a severe and rare infection of the external acoustic meatus. Triphasic bone and (67)Ga scintigraphies are used to initial detect and follow-up the response of therapy. With single photon emission computed tomography/computed tomography images, the diagnostic sensitivity is higher. We presented a case with malignant otitis externa with initial negative planar scintigraphic finding. The lesion was detected by photon emission computed tomography/computed tomography images. We concluded that the photon emission computed tomography/computed tomography should be performed routinely for patients with suspected malignant otitis externa, even without evidence of lesion on planar images. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease

    PubMed Central

    2010-01-01

    Executive Summary In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities. After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website). The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography with Contrast for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis 64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Cardiac

  16. Emission tomography of the kidney

    SciTech Connect

    Teates, C.D.; Croft, B.Y.; Brenbridge, N.A.; Bray, S.T.; Williamson, B.R.

    1983-12-01

    Single photon emission computerized tomography (SPECT) was done on two patients with suspected renal masses. Nuclear scintigraphy was equivocal on two tumors readily identified by SPECT. Single photon tomography is cost effective and increases the reliability of nuclear scintigraphy.

  17. Cerebral Hypoperfusion in Hereditary Coproporphyria (HCP): A Single Photon Emission Computed Tomography (SPECT) Study

    PubMed Central

    Valle, Guido; Guida, Claudio Carmine; Nasuto, Michelangelo; Totaro, Manuela; Aucella, Filippo; Frusciante, Vincenzo; Di Mauro, Lazzaro; Potenza, Adele; Savino, Maria; Stanislao, Mario; Popolizio, Teresa; Guglielmi, Giuseppe; Giagulli, Vito Angelo; Guastamacchia, Edoardo; Triggiani, Vincenzo

    2016-01-01

    Background: Hereditary Coproporphyria (HCP) is characterized by abdominal pain, neurologic symptoms and psychiatric disorders, even if it might remain asymptomatic. The pathophysiology of both neurologic and psychiatric symptoms is not fully understood. Therefore, aiming to evaluate a possible role of brain blood flow disorders, we have retrospectively investigated cerebral perfusion patterns in Single Photon Emission Computed Tomography (SPECT) studies in HCP patients. Materials & Methods: We retrospectively evaluated the medical records of patients diagnosed as being affected by HCP. A total of seven HCP patients had been submitted to brain perfusion SPECT study with 99mTc-Exametazime (hexamethylpropyleneamine oxime, HMPAO) or with its functionally equivalent 99mTc-Bicisate (ECD or Neurolite) according with common procedures. In 3 patients the scintigraphic study had been repeated for a second time after the first evaluation at 3, 10 and 20 months, respectively. All the studied subjects had been also submitted to an electromyographic and a Magnetic Resonance Imaging (MRI) study of the brain. Results: Mild to moderate perfusion defects were detected in temporal lobes (all 7 patients), frontal lobes (6 patients) and parietal lobes (4 patients). Occipital lobe, basal ganglia and cerebellar involvement were never observed. In the three subjects in which SPECT study was repeated, some recovery of hypo-perfused areas and appearance of new perfusion defects in other brain regions have been found. In all patients electromyography resulted normal and MRI detected few unspecific gliotic lesions only in one patient. Discussion & Conclusions: Since perfusion abnormalities were usually mild to moderate, this can probably explain the normal pattern observed at MRI studies. Compared to MRI, SPECT with 99mTc showed higher sensitivity in HCP patients. Changes observed in HCP patients who had more than one study suggest that transient perfusion defects might be due to a brain

  18. Quantitative pulmonary single photon emission computed tomography (SPECT) with radiotherapy applications

    NASA Astrophysics Data System (ADS)

    Scarfone, Christopher

    1998-09-01

    The potential benefits of single photon emission computed tomography (SPECT) lung perfusion imaging for 3- dimensional radiation treatment planning and dose- response analysis, are currently being investigated. Accurate and precise SPECT quantification may facilitate the development of models to predict radiation-induced pulmonary dysfunction prior to treatment. The purpose of this research was to quantitatively evaluate the accuracy and precision of SPECT filtered backprojection (FBP) and maximum likelihood-expectation maximization (ML-EM) image reconstruction methods for measuring absolute and relative activity concentration estimates in the lungs. The investigation is conducted using Monte Carlo simulation and validation, experimental phantom studies and applications to patient data. The scatter response function and scatter fraction (SF) for the lung is measured using Monte Carlo simulation and experimental imaging of point and line sources surrounded by lung density media. The Monte Carlo (experimental) SF value for lung density material is determined to be 14.86% (14.01%) for the line source and 18.88% (20.32%) for the point source. Quantitative experimental evaluation of FBP and ML-EM reconstruction techniques is performed using an anthropomorphic torso phantom containing spherical defects (simulating areas of reduced perfusion) of inner diameters 1.4 cm, 3.4 cm, and 5.6 cm at sphere:background concentration ratios of 0:1, 0.38:1, 0.47:1, 0.51:1, 0.70:1. Quantification is examined as a function of attenuation, scatter constant (k, range = 0.45 to 2.00), total iteration number (5 → 500) and deconvolution (Metz) filter power (X, range = 2.0 to 10.0). Relative (to lung background) and absolute quantification is performed using region of interest (ROI) analysis. A dependence of quantitative accuracy on both defect diameter and density is observed. In general, percent bias increases as defect diameter and density decrease. Also, negative bias in the lung

  19. [Myocardial single photon emission tomography imaging of reporter gene expression in rabbits].

    PubMed

    Liu, Ying; Lan, Xiao-li; Zhang, Liang; Wu, Tao; Jiang, Ri-feng; Zhang, Yong-xue

    2009-06-01

    To explore the feasibility of single photon emission computed tomography (SPECT) detection of heart reporter gene expression and observed the optimal transfecting titer and imaging time by using herpes simplex virus 1-thymidine kinase (HSV1-tk) as reporter gene and 131I-2'-fluoro-2'-deoxy-1-beta-D-arabinofuranosyl-5-iodouracil (131I-FIAU) as reporter probe in rabbit myocardium. The recombinant Ad-tk carrying HSV1-tk gene and adenovirus (Ad) as vector was constructed and intramyocardially injected to rabbits at various concentrations (1 x 10(9) pfu, 5 x 10(8) pfu, 1 x 10(8) pfu, 5 x 10(7) pfu, 1 x 10(7) pfu). Two days later, rabbits were injected with 600 microCi 131I-FIAU in ear-margin vein and then underwent SPECT myocardium imaging for detection of HSV1-tk expression at 6 h, 24 h, 48 h and 72 h after injection, rabbits with 1 x 10(9) pfu Ad-tk injection were imaged at 96 h and 120 h. Rabbits were sacrificed after imaging and the total myocardial 131I-FIAU accumulation was quantified in percent of injected dose per gram myocardium (% ID/g). The myocardial Ad-tk expression was determined with RT-PCR. Reporter gene was detected by SPECT imaging in the injection site while not detected in the control myocardium and site remote from injection. RT-PCR results also evidenced HSV1-tk express in the injection site. The SPECT target/nontarget ratio was correlated with ex vivo gamma-counting (r2 = 0.933, P<0.01) and expression of HSV1-tk (r2 = 0.877, P<0.01). Myocardial accumulation could be identified at viral titers as low as 1 x 10(7) pfu by SPECT imaging. The cardiac SPECT reporter gene imaging with HSV1-tk as reporter gene and 131I-FIAU as reporter probe is feasible.

  20. Evaluating the role of single-photon emission computed tomography in the assessment of neurotologic complaints.

    PubMed

    Joglekar, Shruti S; Bell, Jason R; Caroline, Malka; Chase, Paul J; Domesek, James; Patel, Pinal S; Sataloff, Robert T

    2014-01-01

    We conducted a retrospective study to reexamine the value of single-photon emission computed tomography (SPECT) in the evaluation of patients with neurotologic complaints, and to assess the intra- and inter-radiologist variability of SPECT readings. Our study population was made up of 63 patients--23 men and 40 women, aged 34 to 91 years (mean: 59)--who had presented to a tertiary care otolaryngology practice and university hospital for evaluation of head trauma, sensorineural hearing loss, tinnitus, and/or vertigo. All patients had undergone brain scanning with SPECT during their evaluation, and almost all had also undergone magnetic resonance imaging (MRI) and standard computed tomography (CT). We compared the findings of all three imaging modalities in terms of their ability to detect neurotologic abnormalities. We found that detection rates were very similar among the three modalities; abnormalities were found in 24% of SPECT scans, 26% of MRIs, and 23% of CTs. Nevertheless, we did find that among 60 patients who underwent all three types of imaging, 13 (22%) exhibited areas of cerebral hypoperfusion on SPECT while their MRIs and CTs were read as either normal or nonspecific. In all, 18 of these 60 patients (30%) exhibited normal or nonspecific findings on all three types of imaging. In addition, when SPECT scans were read by the same radiologist at different times, different results were reported for 17 of the 63 scans (27%). Likewise, when SPECT scans were read by different radiologists, different results were reported for 21 of 63 scans (33%). We conclude that SPECT may be a valuable complementary diagnostic modality for making a comprehensive neurotologic evaluation and that it may detect abnormalities in some patients whose other imaging is read as normal. However, we did not find that SPECT was the most sensitive of the three modalities in neurotologic evaluation, as we had previously found in a preliminary study that the senior author (R.T.S.) published

  1. Cerebral Hypoperfusion in Hereditary Coproporphyria (HCP): A Single Photon Emission Computed Tomography (SPECT) Study.

    PubMed

    Valle, Guido; Guida, Claudio Carmine; Nasuto, Michelangelo; Totaro, Manuela; Aucella, Filippo; Frusciante, Vincenzo; Di Mauro, Lazzaro; Potenza, Adele; Savino, Maria; Stanislao, Mario; Popolizio, Teresa; Guglielmi, Giuseppe; Giagulli, Vito Angelo; Guastamacchia, Edoardo; Triggiani, Vincenzo

    2016-01-01

    Hereditary Coproporphyria (HCP) is characterized by abdominal pain, neurologic symptoms and psychiatric disorders, even if it might remain asymptomatic. The pathophysiology of both neurologic and psychiatric symptoms is not fully understood. Therefore, aiming to evaluate a possible role of brain blood flow disorders, we have retrospectively investigated cerebral perfusion patterns in Single Photon Emission Computed Tomography (SPECT) studies in HCP patients. We retrospectively evaluated the medical records of patients diagnosed as being affected by HCP. A total of seven HCP patients had been submitted to brain perfusion SPECT study with 99mTc-Exametazime (hexamethylpropyleneamine oxime, HMPAO) or with its functionally equivalent 99mTc-Bicisate (ECD or Neurolite) according with common procedures. In 3 patients the scintigraphic study had been repeated for a second time after the first evaluation at 3, 10 and 20 months, respectively. All the studied subjects had been also submitted to an electromyographic and a Magnetic Resonance Imaging (MRI) study of the brain. Mild to moderate perfusion defects were detected in temporal lobes (all 7 patients), frontal lobes (6 patients) and parietal lobes (4 patients). Occipital lobe, basal ganglia and cerebellar involvement were never observed. In the three subjects in which SPECT study was repeated, some recovery of hypo-perfused areas and appearance of new perfusion defects in other brain regions have been found. In all patients electromyography resulted normal and MRI detected few unspecific gliotic lesions only in one patient. Discussion & Conclusions: Since perfusion abnormalities were usually mild to moderate, this can probably explain the normal pattern observed at MRI studies. Compared to MRI, SPECT with 99mTc showed higher sensitivity in HCP patients. Changes observed in HCP patients who had more than one study suggest that transient perfusion defects might be due to a brain artery spasm possibly leading to psychiatric

  2. Single-photon emission from InAsP quantum dots embedded in density-controlled InP nanowires

    NASA Astrophysics Data System (ADS)

    Yanase, Shougo; Sasakura, Hirotaka; Hara, Shinjiro; Motohisa, Junichi

    2017-04-01

    We attempted to control the density and size of InP-based nanowires (NWs) and nanowire quantum dots (NW-QDs) during selective-area metalorganic vapor phase epitaxy. InP nanowire arrays with a 5 µm pitch and an average NW diameter d of 67 nm were successfully grown by optimization of growth conditions. InAsP quantum dots were embedded in these density-controlled InP NW arrays, and clear single-photon emission and exciton-biexciton cascaded emission were confirmed by excitation-dependent photoluminescence and photon correlation measurements.

  3. Optical patch antennas for single photon emission using surface plasmon resonances.

    PubMed

    Esteban, R; Teperik, T V; Greffet, J J

    2010-01-15

    Single photon sources can greatly benefit from specially designed structures that modify the properties of the photon emitter. Dielectric cavities are often discussed, but they require a compromise between the spectral width and Purcell factor. In this Letter, we introduce plasmonic cavities as promising alternatives. We first study how the emitter couples with the modes of such structures. We then show how a patch antenna configuration simultaneously presents a large Purcell factor, collection efficiency, and spectral width.

  4. Nearly Blinking-Free, High-Purity Single-Photon Emission by Colloidal InP/ZnSe Quantum Dots.

    PubMed

    Chandrasekaran, Vigneshwaran; Tessier, Mickaël D; Dupont, Dorian; Geiregat, Pieter; Hens, Zeger; Brainis, Edouard

    2017-10-11

    Colloidal core/shell InP/ZnSe quantum dots (QDs), recently produced using an improved synthesis method, have a great potential in life-science applications as well as in integrated quantum photonics and quantum information processing as single-photon emitters. Single-particle spectroscopy of 10 nm QDs with 3.2 nm cores reveals strong photon antibunching attributed to fast (70 ps) Auger recombination of multiple excitons. The QDs exhibit very good photostability under strong optical excitation. We demonstrate that the antibunching is preserved when the QDs are excited above the saturation intensity of the fundamental-exciton transition. This result paves the way toward their usage as high-purity on-demand single-photon emitters at room temperature. Unconventionally, despite the strong Auger blockade mechanism, InP/ZnSe QDs also display very little luminescence intermittency ("blinking"), with a simple on/off blinking pattern. The analysis of single-particle luminescence statistics places these InP/ZnSe QDs in the class of nearly blinking-free QDs, with emission stability comparable to state-of-the-art thick-shell and alloyed-interface CdSe/CdS, but with improved single-photon purity.

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

    NASA Astrophysics Data System (ADS)

    Nikkinen, Paivi Helena

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

  6. CO2BOLD assessment of moyamoya syndrome: Validation with single photon emission computed tomography and positron emission tomography imaging

    PubMed Central

    Pellaton, Alain; Bijlenga, Philippe; Bouchez, Laurie; Cuvinciuc, Victor; Barnaure, Isabelle; Garibotto, Valentina; Lövblad, Karl-Olof; Haller, Sven

    2016-01-01

    AIM To compare the assessment of cerebrovascular reserve (CVR) using CO2BOLD magnetic resonance imaging (MRI) vs positron emission tomography (PET) and single photon emission computed tomography (SPECT) as reference standard. METHODS Ten consecutive patients (8 women, mean age of 41 ± 26 years) with moyamoya syndrome underwent 14 pre-surgical evaluations for external-internal carotid artery bypass surgery. CVR was assessed using CO2BOLD and PET (4)/SPECT (11) with a maximum interval of 36 d, and evaluated by two experienced neuroradiologists. RESULTS The inter-rater agreement was 0.81 for SPECT (excellent), 0.43 for PET (fair) and 0.7 for CO2BOLD (good). In 9/14 cases, there was a correspondence between CO2BOLD and PET/SPECT. In 4/14 cases, CVR was over-estimated in CO2BOLD, while in 1/14 case, CVR was underestimated in CO2BOLD. The sensitivity of CO2BOLD was 86% and a specificity of 43%. CONCLUSION CO2BOLD can be used for pre-surgical assessment of CVR in patients with moyamoya syndrome and combines the advantages of absent irradiation, high availability of MRI and assessment of brain parenchyma, cerebral vessels and surrogate CVR in one stop. PMID:27928470

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

    SciTech Connect

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    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 localization

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

    PubMed Central

    Lee, Chih-Jie; Kupinski, Matthew A.; Volokh, Lana

    2013-01-01

    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 ’s study [“Estimating random signal parameters from noisy images with nuisance parameters: linear and scanning-linear methods,” Opt. Express 16(11), 8150–8173 (2008)]10.1364/OE.16.008150 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

  9. Diagnosis of sclerosing cholangitis with technetium 99m-labeled iminodiacetic acid planar and single photon emission computed tomographic scintigraphy

    SciTech Connect

    Rodman, C.A.; Keeffe, E.B.; Lieberman, D.A.; Krishnamurthy, S.; Krishnamurthy, G.T.; Gilbert, S.; Eklem, M.J.

    1987-03-01

    The purpose of this study was to determine whether /sup 99m/Tc-iminodiacetic acid planar biliary scintigraphy combined with single photon emission computed tomography could detect sclerosing cholangitis and provide additional information regarding the extent and severity of disease. Thirteen patients with sclerosing cholangitis and 13 normal control subjects were studied. Scintigraphic results were also compared with previously reported studies of patients with isolated common bile duct obstruction and with primary biliary cirrhosis. The planar scintigraphy in patients with sclerosing cholangitis showed beading or bandlike constrictions of the biliary tract corresponding to lesions seen on cholangiography, and the image pattern was distinctly different from images obtained from patients with isolated common bile duct obstruction or primary biliary cirrhosis. The single photon emission computed tomography images of the liver in patients with sclerosing cholangitis demonstrated multiple focal areas of /sup 99m/Tc-iminodiacetic acid retention, representing bile stasis in intrahepatic bile ducts. Compared to controls, the mean hepatic clearance half-time of /sup 99m/Tc-iminodiacetic acid was markedly delayed in patients with sclerosing cholangitis (6-10 times normal). Individual patients with sclerosing cholangitis had wider variation in isotope clearance half-time from three regions of the liver than patients with isolated common bile duct obstruction, consistent with regional difference in disease severity and variable impairment of bile flow. In 4 patients with sclerosing cholangitis with incomplete filling of the right and left hepatic ducts at cholangiography, planar and single photon emission computed tomographic scintigraphy provided evidence of significant intrahepatic sclerosing cholangitis.

  10. Domestic Development of Single-Photon Emission Computed Tomography (SPECT) Unit with Detector based on Silicon Photomultipliers

    NASA Astrophysics Data System (ADS)

    Grishakov, S.; Ryzhikova, O.; Sergienko, V.; Ansheles, A.; Novikov, S.

    2017-01-01

    The idea of creating a single-photon emission computed tomography unit with solid-state photomultipliers is not new [1], as the problems of analog-to-digital conversion with a lot of noise and a wide range of values of intrinsic spatial resolution of the detector in a center and relevant fields of view could not be solved by means of gamma-camera detector architectures based on vacuum photomultipliers. This paper offers a new SPECT imaging solution that is free from these problems.

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

    PubMed Central

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

    2016-01-01

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

  12. Single photon emission photography/magnetic resonance imaging (SPECT/MRI) visualization for frontal-lobe-damaged regions

    NASA Astrophysics Data System (ADS)

    Stokking, Rik; Zuiderveld, Karel J.; Hulshoff Pol, Hilleke E.; Viergever, Max A.

    1994-09-01

    We present multi-modality visualization strategies to convey information contained in registered Single Photon Emission Photography (SPECT) and Magnetic Resonance (MR) images of the brain. Multi-modality visualization provides a means to retrieve valuable information from the data which might otherwise remain obscured. Here we use MRI as an anatomical framework for functional information acquired with SPECT. This is part of clinical research studying the change of functionality caused by a frontal lobe damaged region. A number of known and newly developed techniques for the integrated visualization of SPECT and MR images will be discussed.

  13. Room-temperature single-photon emission from zinc oxide nanoparticle defects and their in vitro photostable intrinsic fluorescence

    NASA Astrophysics Data System (ADS)

    Chung, Kelvin; Karle, Timothy J.; Khalid, Asma; Abraham, Amanda N.; Shukla, Ravi; Gibson, Brant C.; Simpson, David A.; Djurišic, Aleksandra B.; Amekura, Hiroshi; Tomljenovic-Hanic, Snjezana

    2017-01-01

    Zinc oxide (ZnO) is a promising semiconductor that is suitable for bioimaging applications due to its intrinsic defect fluorescence. However, ZnO generally suffers from poor photostability. We report room-temperature single-photon emission from optical defects found in ZnO nanoparticles (NPs) formed by ion implantation followed by thermal oxidation in a silica substrate. We conduct a thorough investigation into the photophysics of a particularly bright defect and identify other single emitters within the NPs. Photostability was observed when the NPs were removed from the growth substrate and taken up by skin cells for in vitro imaging.

  14. Right parietal stroke with Gerstmann's syndrome. Appearance on computed tomography, magnetic resonance imaging, and single-photon emission computed tomography.

    PubMed

    Moore, M R; Saver, J L; Johnson, K A; Romero, J A

    1991-04-01

    We examined a patient who exhibited Gerstmann's syndrome (left-right disorientation, finger agnosia, dyscalculia, and dysgraphia) in association with a perioperative stroke in the right parietal lobe. This is the first description of the Gerstmann tetrad occurring in the setting of discrete right hemisphere pathologic findings. A well-localized vascular lesion was demonstrated by computed tomography, magnetic resonance imaging, and single-photon emission computed tomographic studies. The patient had clinical evidence of reversed functional cerebral dominance and radiologic evidence of reversed anatomic cerebral asymmetries.

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

    PubMed

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

    2014-07-01

    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 navicular bone where three phase bone scan is equivocal.

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

    PubMed Central

    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 navicular bone where three phase bone scan is equivocal. PMID:25210293

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

    SciTech Connect

    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.

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

    SciTech Connect

    Hill, T.C.; Holman, B.L.; Lovett, R.; O'Leary, D.H.; Front, D.; Magistretti, P.; Zimmerman, R.E.; Moore, S.; Clouse, M.E.; Wu, J.L.; Lin, T.H.; Baldwin, R.M.

    1982-03-01

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

  19. Single Cesium Lead Halide Perovskite Nanocrystals at Low Temperature: Fast Single-Photon Emission, Reduced Blinking, and Exciton Fine Structure

    PubMed Central

    2016-01-01

    Metal-halide semiconductors with perovskite crystal structure are attractive due to their facile solution processability, and have recently been harnessed very successfully for high-efficiency photovoltaics and bright light sources. Here, we show that at low temperature single colloidal cesium lead halide (CsPbX3, where X = Cl/Br) nanocrystals exhibit stable, narrow-band emission with suppressed blinking and small spectral diffusion. Photon antibunching demonstrates unambiguously nonclassical single-photon emission with radiative decay on the order of 250 ps, representing a significant acceleration compared to other common quantum emitters. High-resolution spectroscopy provides insight into the complex nature of the emission process such as the fine structure and charged exciton dynamics. PMID:26771336

  20. Cascaded emission of linearly polarized single photons from positioned InP/GaInP quantum dots

    SciTech Connect

    Braun, T.; Unsleber, S.; Baumann, V.; Schneider, C.; Höfling, S.; Kamp, M.; Gschrey, M.; Rodt, S.; Reitzenstein, S.

    2013-11-04

    We report on the optical characterization of site-controlled InP/GaInP quantum dots (QDs). Spatially resolved low temperature cathodoluminescence proves the long-range ordering of the buried emitters, revealing a yield of ∼90% of optically active, positioned QDs and a strong suppression of emitters on interstitial positions. The emission of single QDs shows a pronounced degree of linear polarization along the [0,−1,1] crystal axis with an average degree of polarization of 94%. Photon correlation measurements of the emission from a single QD indicate the single-photon character of the exciton and biexciton emission lines as well as the cascaded nature of the photon pair.

  1. Purcell-Enhanced Single-Photon Emission from Nitrogen-Vacancy Centers Coupled to a Tunable Microcavity

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Optical microcavities are a powerful tool for enhancing the fluorescence of individual quantum emitters. However, the broad emission spectra encountered in the solid state at room temperature limit the influence of a cavity, calling for an ultrasmall mode volume. We demonstrate Purcell-enhanced single-photon emission from nitrogen-vacancy centers in nanodiamonds coupled to a tunable fiber-based microcavity with a mode volume down to 1.0 λ3. We record cavity-enhanced fluorescence images and study several single emitters with one cavity. The Purcell effect is evidenced by enhanced fluorescence collection and tunable lifetime modification, and we infer an effective Purcell factor of up to 2. Furthermore, we show an alternative regime for light confinement, where a Fabry-Perot mode is combined with additional mode confinement by the nanocrystal itself. Simulations predict effective Purcell factors of up to 11 for nitrogen-vacancy centers and 63 for silicon-vacancy centers, holding promise for bright single-photon sources and efficient spin readout under ambient conditions.

  2. Optic nerve sheath meningioma detected by single- photon emission computed tomography/computed tomography somatostatin receptor scintigraphy: a case report.

    PubMed

    Nussbaum-Hermassi, Lucie; Ahle, Guido; Zaenker, Chistophe; Duca, Camelia; Namer, Izzie Jacques

    2016-04-22

    Optic nerve sheath meningiomas account for only 2% of orbital lesions and 42% of optic nerve tumors. Diagnosis remains difficult because histologic confirmation carries a high risk of visual loss. Therefore, a less invasive and specific diagnostic method for differentiating optic nerve sheath meningiomas from other optic nerve lesions is needed to overcome the limitations of computed tomography and magnetic resonance imaging, and make the best individualized treatment decision. This case is a good illustration of the clinical and imaging difficulties inherent in this rare tumor, which may be hard to differentiate from other causes. A 51-year-old Caucasian woman developed a central scotoma, visual loss, and abnormal visual evoked potentials. The first magnetic resonance imaging scan classified the optic nerve damage as retrobulbar optic neuritis. After magnetic resonance imaging follow-up at 3 months, a negative lumbar puncture and biological workup, and clinical worsening, an optic nerve sheath meningioma was suspected. We confirmed this diagnosis with 111In-pentetreotide single-photon emission computed tomography, which is able to bind with very high affinity to somatostatin receptor subtype 2 expressed on meningiomas. In the diagnosis of optic nerve sheath meningiomas, [111In]-pentetreotide single-photon emission computed tomography-fused magnetic resonance imaging is a valuable additional tool, optimizing the diagnosis and obviating the need for a more invasive procedure.

  3. Method for Studying the Myocardial Blood Flow Reserve by Load Dynamic Single-Photon Emission Computed Tomography.

    PubMed

    Mochula, A V; Zavadovsky, K V; Lishmanov, Yu B

    2016-04-01

    We developed a method for collection and processing of scintigraphic data to estimate myocardial reserve in a gamma-chamber with cadmium-zinc-telluride detectors. Dynamic single-photon emission computed tomography of the heart with (99m)Tc-Technetril was performed in 16 coronary heart disease patients at rest and during pharmacological load. During data processing, regions of interest from the cavity and the myocardium of the left ventricle were formed and activity-time curves were constructed. The index of myocardial blood fl ow reserve was calculated as the difference between two ratios of the mean gamma-count from the myocardial area to the area under the left ventricle cavity curve (peak) during load and at rest. The mean indices of myocardial reserve in healthy volunteers and patients with coronary artery atherosclerosis were 1.86 (1.59; 2.20) and 1.39 (1.12; 1.69), respectively. The development of the method for studying myocardial reserve by single-photon emission computed tomography is an urgent problem and requires further investigations.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Efficient single photon emission from a high-purity hexagonal boron nitride crystal

    NASA Astrophysics Data System (ADS)

    Martínez, L. J.; Pelini, T.; Waselowski, V.; Maze, J. R.; Gil, B.; Cassabois, G.; Jacques, V.

    2016-09-01

    Among a variety of layered materials used as building blocks in van der Waals heterostructures, hexagonal boron nitride (hBN) appears as an ideal platform for hosting optically active defects owing to its large band gap (˜6 eV ). Here we study the optical response of a high-purity hBN crystal under green laser illumination. By means of photon correlation measurements, we identify individual defects emitting a highly photostable fluorescence under ambient conditions. A detailed analysis of the photophysical properties reveals a high quantum efficiency of the radiative transition, leading to a single photon source with very high brightness (˜4 ×106 counts s-1). These results illustrate how the wide range of applications offered by hBN could be further extended to photonic-based quantum information science and metrology.

  6. The role of single-photon emission computed tomography and SPECT/computed tomography in oncologic imaging.

    PubMed

    Brandon, David; Alazraki, Adina; Halkar, Raghuveer K; Alazraki, Naomi P

    2011-02-01

    Single-photon emission computed tomography (SPECT) and hybrid SPECT/computed tomography (SPECT/CT) cameras have emerged as a dominant technology providing invaluable tools in the diagnosis, staging, therapy planning, and treatment monitoring of multiple cancers over the past decade. In the same way that positron emission tomography (PET) benefited from the addition of CT, functional SPECT and anatomic CT data obtained as a single study have shown improvements in diagnostic imaging sensitivity and specificity by improving lesion conspicuity, reducing false positives, and clarifying indeterminate lesions. Furthermore, the anatomic imaging better localizes the functional data, which can be critical in surgical and therapy planning. As more disease-specific imaging agents become available, the role of SPECT/CT in the new paradigms of molecular imaging for personalized medicine will expand. Established and emerging uses of SPECT/CT in a wide variety of oncologic diseases, as well as radiation exposure issues, are reviewed. Published by Elsevier Inc.

  7. Nanoscale optical positioning of single quantum dots for bright and pure single-photon emission

    PubMed Central

    Sapienza, Luca; Davanço, Marcelo; Badolato, Antonio; Srinivasan, Kartik

    2015-01-01

    Self-assembled, epitaxially grown InAs/GaAs quantum dots (QDs) are promising semiconductor quantum emitters that can be integrated on a chip for a variety of photonic quantum information science applications. However, self-assembled growth results in an essentially random in-plane spatial distribution of QDs, presenting a challenge in creating devices that exploit the strong interaction of single QDs with highly confined optical modes. Here, we present a photoluminescence imaging approach for locating single QDs with respect to alignment features with an average position uncertainty <30 nm (<10 nm when using a solid-immersion lens), which represents an enabling technology for the creation of optimized single QD devices. To that end, we create QD single-photon sources, based on a circular Bragg grating geometry, that simultaneously exhibit high collection efficiency (48%±5% into a 0.4 numerical aperture lens, close to the theoretically predicted value of 50%), low multiphoton probability (g(2)(0) <1%), and a significant Purcell enhancement factor (≈3). PMID:26211442

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

    PubMed

    Larsson, S A; Jonsson, C; Pagani, M; Johansson, L; Jacobsson, H

    2000-02-01

    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 "real

  9. Single-photon quadratic optomechanics

    PubMed Central

    Liao, Jie-Qiao; Nori, Franco

    2014-01-01

    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 optomechanical coupling strength, the mechanical frequency, and the cavity-field decay rate. In particular, we clarify the conditions for the phonon sidebands to be visible. We also study the photon-phonon entanglement for the long-time emission and scattering states. The linear entropy is employed to characterize this entanglement by treating it as a bipartite one between a single mode of phonons and a single photon. PMID:25200128

  10. Long-term noninvasive single photon emission computed tomography monitoring of perfusional changes after EC-IC bypass surgery.

    PubMed Central

    Di Piero, V; Lenzi, G L; Collice, M; Triulzi, F; Gerundini, P; Perani, D; Savi, A R; Fieschi, C; Fazio, F

    1987-01-01

    The rCBF was evaluated using I-123 HIPDM and single photon emission computed tomography (SPECT) on 14 patients undergoing extracranial-intracranial (EC-IC) bypass surgery because of internal carotid artery (ICA) occlusion. Before surgery, all patients showed cortical areas of hypoperfusion over the affected cerebral hemisphere. Shortly after EC-IC bypass a rCBF increase was observed in six patients. However, at the 6 and 12 month follow-ups, with angiographic control of bypass patency, rCBF studies did not show any significant rCBF change. Long-term noninvasive tomographic monitoring of perfusion changes occurring after EC-IC bypass surgery failed to show a long-lasting improvement in perfusion. Images PMID:3498800

  11. Muscarinic cholinergic receptor binding: in vivo depiction using single photon emission computed tomography and radioiodinated quinuclidinyl benzilate

    SciTech Connect

    Drayer, B.; Jaszczak, R.; Coleman, E.; Storni, A.; Greer, K.; Petry, N.; Lischko, M.; Flanagan, S.

    1982-06-01

    An attempt was made to characterize, in vivo, specific binding to the muscarinic cholinergic receptor in the calf using the radioiodinated ligand quinuclidinyl benzilate (/sup 123/I-OH-QNB) and single photon detection emission computed tomography (SPECT). The supratentorial brain activity was significantly increased after the intravenous infusion of /sup 123/I-OH-QNB as compared to free /sup 123/I. Scopolamine, a muscarinic cholinergic receptor antagonist, decreased the measured brain activity when infused prior to /sup 123/I-OH-QNB consistent with pharmacologic blockade of specific receptor binding. Quantitative in vitro tissue distribution studies obtained following SPECT imaging were consistent with regionally distinct specific receptor binding in the striatum and cortical gray matter, nonspecific binding in the cerebellum, and pharmacologic blockade of specific binding sites with scopolamine. Although /sup 123/I-OH-QNB is not the ideal radioligand, our limited success will hopefully encourage the development of improved binding probes for SPECT imaging and quantitation.

  12. Left leg apraxia after anterior cerebral artery territory infarction: functional analysis using single-photon emission computed tomography.

    PubMed

    Ito, Ikuno; Ito, Kimiteru; Shindo, Naoko

    2013-01-01

    Left hand apraxia is known as a unique symptom of callosal apraxia, but lower limb symptoms are rarely mentioned. We report a patient who experienced left ideomotor apraxia affecting both the upper and lower limbs after a stroke in the territory of the right anterior cerebral artery. His spontaneous gait was normal, but he was unable to move his left leg intentionally either by verbal command or by imitation. His leg symptoms gradually improved over time. We evaluated the change in cerebral blood flow in this patient using single-photon emission computed tomography. The results showed an increase in blood flow in the posterior corpus callosum; therefore, we suggested that the callosal pathway might contribute to left leg as well as left hand volitional movement. Copyright © 2013 S. Karger AG, Basel.

  13. Design and Feasibility Study of a Single Photon Emission Microscope System for Small Animal I-125 Imaging

    PubMed Central

    Meng, L. J.; Clinthorne, N. H.; Skinner, S.; Hay, R. V.; Gross, M.

    2016-01-01

    This paper presents a design study of a single photon emission microscope (SPEM) system for small animal imaging using I-125 labelled radiotracers. This system is based on the use of a very-high resolution gamma camera coupled to a converging non-multiplexing multiple pinhole collimator. This enables one to “zoom” into a small local region inside the object to extract imaging information with a very high spatial resolution and a reasonable sensitivity for gamma rays emitted from this local region. The SPEM system also includes a pinhole (or multiple pinhole) gamma camera that has a full angular coverage of the entire object. The designed imaging spatial resolution for the SPEM system is between 250 μm to 500 μm FWHM.

  14. Laparoscopic Sentinel Node Biopsy Using Real-time 3-dimensional Single-photon Emission Computed Tomographic Guidance in Endometrial Cancer.

    PubMed

    Fernandez-Prada, Sara; Delgado-Sanchez, Elsa; De Santiago, Javier; Zapardiel, Ignacio

    2015-01-01

    In endometrial cancer, the histopathological analysis of the lymphatic nodes is essential to establish a correct prognosis and tailored adjuvant treatment. It is well-known that patients with early-stage endometrial cancer have a low incidence of nodal disease. In this group, systematic lymphadenectomy is not recommended. To improve the detection rate of sentinel nodes in clinical practice, new techniques are emerging like real-time 3-dimensional single-photon emission computed tomographic (SPECT) imaging. We report our experience using this innovative technique for intraoperative detection of sentinel nodes in endometrial cancer. The real-time 3-dimensional SPECT sentinel node biopsy seems to be feasible and accurate in endometrial cancer although further studies are needed to set the precision and predictive values compared with the current differed SPECT techniques and blue dye techniques. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

  15. Hepatic cavernous hemangioma: diagnosis with /sup 99m/Tc-labeled red cells and single-photon emission CT

    SciTech Connect

    Brodsky, R.I.; Friedman, A.C.; Maurer, A.H.; Radecki, P.D.; Caroline, D.F.

    1987-01-01

    During the performance of high-resolution real-time abdominal sonography, small echogenic hepatic masses are frequently discovered. A second imaging test to confirm the suspected diagnosis of hemangioma is often required. Planar labeled red-cell imaging will often not detect hemangiomas smaller than 3 cm. We studied 14 patients with labeled red-cell scintigraphy and single-photon emission CT (SPECT). Six hemangiomas were diagnosed by SPECT that would have been missed by planar imaging alone. All six were smaller than 2.5 cm. With the addition of SPECT, labeled red-cell scintigraphy has specificity and sensitivity that make it at least as reliable as dynamic CT for the noninvasive diagnosis of hepatic cavernous hemangioma.

  16. Evaluation of extracranial-to-intracranial bypass surgery using iodine 123 iodoamphetamine single-photon emission computed tomography

    SciTech Connect

    Kobayashi, H.; Hayashi, M.; Kawano, H.; Handa, Y.; Kabuto, M.; Maeda, H.; Ishii, Y. )

    1991-06-01

    Eleven patients with occlusive cerebrovascular diseases were imaged with N-isopropyl-p-I-123 iodoamphetamine. Preoperative and postoperative single-photon emission computed tomography was performed in 10 patients undergoing extracranial-to-intracranial bypass procedures. New images were reconstructed from the two images obtained on the different days by superimposition and division in each pixel to get the ratio of cerebral perfusion change. All patients with bypass procedures had an increase in cerebral blood flow in the affected areas, and nine of 10 had an increase in cerebral blood flow in the contralateral cortex. There was no increase in cerebral blood flow in one case with no operation. Neither our procedure nor the results in this small series prove that recovery of function is due to an increase in blood flow, but we believe this is the case.

  17. Breath-hold single-photon emission tomography and computed tomography for predicting residual pulmonary function in patients with lung cancer.

    PubMed

    Sudoh, Manabu; Ueda, Kazuhiro; Kaneda, Yoshikazu; Mitsutaka, Jinbo; Li, Tao-Sheng; Suga, Kazuyoshi; Kawakami, Yasuhiko; Hamano, Kimikazu

    2006-05-01

    We sought to evaluate the utility of integrated breath-hold single-photon emission tomography and computed tomography imaging compared with that of simple calculation with the lung segment-counting technique for predicting residual pulmonary function in patients undergoing surgical intervention for lung cancer. A prospective series of 22 patients undergoing anatomic lung resection for cancer were enrolled in this study. Postoperative residual forced expiratory volume in 1 second was predicted by measuring the radioactivity counts of the affected lobes or segments to be resected within the entire lungs by placement of regions of interest on single-photon emission tomography and computed tomography images. Residual forced expiratory volume in 1 second was also estimated by using the segment-counting technique. Both predicted values agreed well with postoperative forced expiratory volume in 1 second. Although the residual forced expiratory volume in 1 second predicted by means of single-photon emission tomography and computed tomography correlated well with that predicted by using segment counting, the values were significantly underestimated by the segment-counting technique in 4 outliers with severe emphysema. There were 2 patients with borderline pulmonary functional reserve whose residual forced expiratory volume in 1 second values were predicted more accurately by means of single-photon emission tomography and computed tomography than by using segment counting. Integrated breath-hold single-photon emission tomography and computed tomography images allow the accurate prediction of postoperative pulmonary function but without statistical superiority over the simple segment-counting technique. Further study of the usefulness of single-photon emission tomography and computed tomography in patients with severe emphysema and borderline lung function should prove valuable because the segment-counting technique underestimates pulmonary functional reserve in these

  18. Single Photon Emission Computed Tomography-Based Three-Dimensional Conformal Radiotherapy for Hepatocellular Carcinoma With Portal Vein Tumor Thrombus

    SciTech Connect

    Shirai, Shintaro; Sato, Morio Suwa, Kazuhiro; Kishi, Kazushi; Shimono, Chigusa; Kawai, Nobuyuki; Tanihata, Hirohiko; Minamiguchi, Hiroki; Nakai, Motoki

    2009-03-01

    Purpose: To evaluate the safety and efficacy of three-dimensional conformal radiotherapy (3D-CRT) using single photon emission computed tomography (SPECT) in unresectable hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT). Methods and Materials: Patients with HCC with PVTT in the first branch and/or main trunk were selected for this study. The optimal beam directions for 3D-CRT were explored using a Tc-99m-galactosyl human serum albumin SPECT image for guidance. The SPECT image was classified as either wedge type or localized type. The clinical target volume to a total dose of 45 or 50 Gy per 18-20 fractions included the main tumor and PVTT in the wedge type and PVTT alone in the localized type. Results: Twenty-six patients were enrolled: 18 with wedge type and 8 with localized type. Mean tumor size was 7.1 cm (range, 4.4-12.3 cm). Clinical target volumes of wedge type vs. localized type were 111.2 cm{sup 3} vs. 48.4 cm{sup 3} (p = 0.010), respectively. Mean dose to normal liver and mean dose to functional liver were 1185 cGy and 988 cGy (p = 0.001) in wedge type and 1046 cGy and 1043 cGy (p = 0.658) in localized type, respectively. Despite an incidence of Child-Pugh B and C of 57.7%, no patients experienced radiation-induced liver disease. The progression of PVTT was inhibited, with an incidence of 92.2%; survival rates at 1 and 2 years were 44% and 30%, respectively. Conclusion: Single photon emission computed tomography-based 3D-CRT enables irradiation of both the main tumor and PVTT with low toxicity and promising survival.

  19. Comparison of left ventricular ejection fraction values obtained using invasive contrast left ventriculography, two-dimensional echocardiography, and gated single-photon emission computed tomography

    PubMed Central

    Garg, Nadish; Dresser, Thomas; Aggarwal, Kul; Gupta, Vishal; Mittal, Mayank K; Alpert, Martin A

    2016-01-01

    Objectives: Left ventricular ejection fraction can be measured by a variety of invasive and non-invasive cardiac techniques. This study assesses the relation of three diagnostic modalities to each other in the measurement of left ventricular ejection fraction: invasive contrast left ventriculography, two-dimensional echocardiography, and quantitative gated single-photon emission computed tomography. Methods: Retrospective chart review was conducted on 58 patients hospitalized with chest pain, who underwent left ventricular ejection fraction evaluation using each of the aforementioned modalities within a 3-month period not interrupted by myocardial infarction or revascularization. Results: The mean left ventricular ejection fraction values were as follows: invasive contrast left ventriculography (0.44±0.15), two-dimensional echocardiography (0.46±0.13), and gated single-photon emission computed tomography (0.37±0.10). Correlations coefficients and associated p values were as follows: invasive contrast left ventriculography versus two-dimensional echocardiography (r=0.69, p<0.001), invasive contrast left ventriculography versus gated single-photon emission computed tomography (r=0.80, p<0.0001), and gated single-photon emission computed tomography versus two-dimensional echocardiography (r=0.69, p<0.001). Conclusion: Our results indicate that strong positive correlations exist among the three techniques studied. PMID:27621804

  20. Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography

    SciTech Connect

    Tamaki, N.; Yonekura, Y.; Senda, M.; Yamashita, K.; Koide, H.; Saji, H.; Hashimoto, T.; Fudo, T.; Kambara, H.; Kawai, C.

    1988-07-01

    The diagnostic value of exercise /sup 201/Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise (13N) ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injections.

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

    SciTech Connect

    Deshpande, Saniya; Frost, Thomas; Hazari, Arnab; Bhattacharya, Pallab

    2014-10-06

    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 In{sub 0.4}Ga{sub 0.6}N/GaN quantum dots exhibit a second-order correlation value g{sup (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.

  2. Quantum interference and radiative coupling in two-atom single-photon emission

    NASA Astrophysics Data System (ADS)

    Kurizki, G.; Ben-Reuven, A.

    1985-10-01

    The recent experiment by Grangier, Aspect, and Vigue on interference in the emission from fragments of electronically photodissociated molecules is treated as a special case of cooperative fluorescence (CF) from products of various molecular processes. This treatment relates time-resolved features of the CF to characteristics (such as orbital symmetry) of the dissociating parent molecule (PM), suggests various PM state preparations (including formation of subradiant states), and discusses the persistence of CF in systems of nonidentical fragments. The diagnostic potentialities of such studies are emphasized.

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

    PubMed

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

    2016-12-01

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

  4. Diagnostic accuracy of exercise thallium-201 single-photon emission computed tomography in patients with left bundle branch block.

    PubMed

    Larcos, G; Gibbons, R J; Brown, M L

    1991-09-15

    Recent reports have proposed that abnormal apical or anterior wall perfusion with exercise thallium-201 imaging may increase diagnostic accuracy for disease of the left anterior descending artery in patients with left bundle branch block (LBBB). To evaluate these suggestions, 83 patients with LBBB who underwent thallium-201 single-photon emission computed tomography and coronary angiography within an interval of 3 months were retrospectively reviewed. There were 59 men and 24 women aged 33 to 84 years (mean 65). Myocardial perfusion to the apex, anterior wall and anterior septum were scored qualitatively by consensus of 2 experienced observers and by quantitative analysis in comparison with a normal data base. The sensitivity, specificity and accuracy of perfusion defects in these segments were then expressed according to angiographic findings. Significant stenosis of vessels within the left anterior descending artery territory was present in 38 patients. By receiver-operator characteristic analysis, a fixed or reversible defect within the apex by the qualitative method was the best criterion for coronary artery disease. However, although highly sensitive (79 and 85% by the qualitative and quantitative methods, respectively), an apical defect was neither specific (38 and 16%, respectively), nor accurate (57 and 46%, respectively). Perfusion abnormalities in the anterior wall and septum were also of limited diagnostic accuracy. Thus, modified interpretative criteria in patients with LBBB are not clinically useful in the assessment of left anterior descending artery disease.

  5. The association between heroin expenditure and dopamine transporter availability--a single-photon emission computed tomography study.

    PubMed

    Lin, Shih-Hsien; Chen, Kao Chin; Lee, Sheng-Yu; Chiu, Nan Tsing; Lee, I Hui; Chen, Po See; Yeh, Tzung Lieh; Lu, Ru-Band; Chen, Chia-Chieh; Liao, Mei-Hsiu; Yang, Yen Kuang

    2015-03-30

    One of the consequences of heroin dependency is a huge expenditure on drugs. This underlying economic expense may be a grave burden for heroin users and may lead to criminal behavior, which is a huge cost to society. The neuropsychological mechanism related to heroin purchase remains unclear. Based on recent findings and the established dopamine hypothesis of addiction, we speculated that expenditure on heroin and central dopamine activity may be associated. A total of 21 heroin users were enrolled in this study. The annual expenditure on heroin was assessed, and the availability of the dopamine transporter (DAT) was assessed by single-photon emission computed tomography (SPECT) using [(99m)TC]TRODAT-1. Parametric and nonparametric correlation analyses indicated that annual expenditure on heroin was significantly and negatively correlated with the availability of striatal DAT. After adjustment for potential confounders, the predictive power of DAT availability was significant. Striatal dopamine function may be associated with opioid purchasing behavior among heroin users, and the cycle of spiraling dysfunction in the dopamine reward system could play a role in this association.

  6. Technetium-99m Methylene Diphosphonate Single-photon Emission Computed Tomography/Computed Tomography of the Foot and Ankle

    PubMed Central

    Upadhyay, Bhavin; Mo, Jonathan; Beadsmoore, Clare; Marshall, Tom; Toms, Andoni; Buscombe, John

    2017-01-01

    The complex anatomy and function of the foot and ankle can make it difficult to determine the cause of symptoms in patients with foot and ankle pathology. Following initial clinical and radiographic assessment, additional imaging with magnetic resonance imaging may be required, which is often seen as the modality of choice. Although sensitive to pathological changes in bone metabolism and vascularity, technetium-99m (Tc-99m) bone scintigraphy often lacks the specificity and resolution required to evaluate the structures of the foot and ankle. Tc-99m methylene diphosphonate single-photon emission computed tomography/computed tomography (SPECT/CT) combines this sensitivity with the superior anatomical detail of CT, enabling better localization of pathological uptake and evaluation of associated structural changes. As a result, SPECT/CT has been growing in popularity for the assessment of patients with foot and ankle pathology where it can provide additional information that may change the initial diagnosis and subsequent management plan. Studies have reported modification of the surgical approach and site of intra-articular local anesthetic injections following SPECT/CT with good results. Interpretation of SPECT/CT studies requires an understanding of the pathological changes that result in increased tracer accumulation in addition to the CT changes that may be seen. This review aims to highlight the advantages of SPECT/CT, potential applications and explain the imaging appearances of common pathologies that may be observed. PMID:28553174

  7. Radiolabeling, whole-body single photon emission computed tomography/computed tomography imaging, and pharmacokinetics of carbon nanohorns in mice

    PubMed Central

    Zhang, Minfang; Jasim, Dhifaf A; Ménard-Moyon, Cécilia; Nunes, Antonio; Iijima, Sumio; Bianco, Alberto; Yudasaka, Masako; Kostarelos, Kostas

    2016-01-01

    In this work, we report that the biodistribution and excretion of carbon nanohorns (CNHs) in mice are dependent on their size and functionalization. Small-sized CNHs (30–50 nm; S-CNHs) and large-sized CNHs (80–100 nm; L-CNHs) were chemically functionalized and radiolabeled with [111In]-diethylenetriaminepentaacetic acid and intravenously injected into mice. Their tissue distribution profiles at different time points were determined by single photon emission computed tomography/computed tomography. The results showed that the S-CNHs circulated longer in blood, while the L-CNHs accumulated faster in major organs like the liver and spleen. Small amounts of S-CNHs- and L-CNHs were excreted in urine within the first few hours postinjection, followed by excretion of smaller quantities within the next 48 hours in both urine and feces. The kinetics of excretion for S-CNHs were more rapid than for L-CNHs. Both S-CNH and L-CNH material accumulated mainly in the liver and spleen; however, S-CNH accumulation in the spleen was more prominent than in the liver. PMID:27524892

  8. THE ATTENUATED RADON TRANSFORM: APPLICATION TO SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY IN THE PRESENCE OF A VARIABLE ATTENUATING MEDIUM

    SciTech Connect

    Gullberg, Grant T.

    1980-03-01

    The properties of the attenuated Radon transform and its application to single-photon emission computed tomography (ECT) are analyzed in detail. In nuclear medicine and biological research, the objective of ECT is to describe quantitatively the position and strengths of internal sources of injected radiopharmaceuticals and radionuclides where the attenuation between the sources and detector is unknown. The problem is mathematically and practically quite different from well-known methods in transmission computed tomography (TCT) where only the attenuation is unknown. A mathematical structure using function theory and the theory of linear operators on Hilbert spaces is developed to better understand the spectral properties of the attenuated Radon transform. The continuous attenuated Radon transform is reduced to a matrix operator for discrete angular and lateral sampling, and the reconstruction problem reduces to a system of linear equations. For variable attenuation coefficients frequently found in imaging internal organs, the numerical methods developed in this paper involve iterative techniques of performing the generalized inverse. Its application to nuclear medicine is demonstrated by reconstructions of transverse sections of the brain, heart, and liver.

  9. Effect of caffeine on myocardial perfusion imaging using single photon emission computed tomography during adenosine pharmacologic stress.

    PubMed

    Kovacs, Daniela; Pivonka, Robert; Khosla, Pam G; Khosla, Sandeep

    2008-01-01

    Approximately 6 million cardiac stress tests are performed annually in the United States, of which 2.4 million are pharmacologic stress tests using agents such as adenosine. Adenosine induces differential coronary hyperemia in normal coronary arteries versus coronary arteries with atherosclerosis, allowing single photon emission computed tomography (SPECT) imaging to identify reduced coronary flow in segments subtended by diseased coronary arteries. The potential attenuation of pharmacologic effects of adenosine in the presence of caffeine is why patients are routinely instructed to abstain from caffeine for 12 to 24 hours prior to administration of an adenosine stress test. Failure to abstain from caffeine results in cancellation or delaying of cardiac stress testing, resulting in procedural delays and its impact on patient throughput. Recent studies have evaluated such interaction and suggested a lack of clinically significant effect of caffeine on adenosine-induced hyperemia during myocardial SPECT imaging. This article reviews the clinical pharmacology of caffeine, adenosine, and dipyridamole and effect of caffeine on myocardial stress testing using adenosine and dipyridamole in clinical cardiovascular medicine. The limited published data are conflicting, but some recent publications suggest that myocardial perfusion SPECT imaging using adenosine may not be clinically significantly altered by routine consumption of caffeine, such as a cup of coffee. Although prospective randomized studies would be required to obtain a definitive answer to this question, it appears on the basis of some of the studies reviewed in this article that caffeine consumption prior to myocardial perfusion imaging may not necessitate cancellation or rescheduling of adenosine stress testing.

  10. Bilateral symmetry aspects in computer-aided Alzheimer's disease diagnosis by single-photon emission-computed tomography imaging.

    PubMed

    Illán, Ignacio Alvarez; Górriz, Juan Manuel; Ramírez, Javier; Lang, Elmar W; Salas-Gonzalez, Diego; Puntonet, Carlos G

    2012-11-01

    This paper explores the importance of the latent symmetry of the brain in computer-aided systems for diagnosing Alzheimer's disease (AD). Symmetry and asymmetry are studied from two points of view: (i) the development of an effective classifier within the scope of machine learning techniques, and (ii) the assessment of its relevance to the AD diagnosis in the early stages of the disease. The proposed methodology is based on eigenimage decomposition of single-photon emission-computed tomography images, using an eigenspace extension to accommodate odd and even eigenvectors separately. This feature extraction technique allows for support-vector-machine classification and image analysis. Identification of AD patterns is improved when the latent symmetry of the brain is considered, with an estimated 92.78% accuracy (92.86% sensitivity, 92.68% specificity) using a linear kernel and a leave-one-out cross validation strategy. Also, asymmetries may be used to define a test for AD that is very specific (90.24% specificity) but not especially sensitive. Two main conclusions are derived from the analysis of the eigenimage spectrum. Firstly, the recognition of AD patterns is improved when considering only the symmetric part of the spectrum. Secondly, asymmetries in the hypo-metabolic patterns, when present, are more pronounced in subjects with AD. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Magnetic Resonance Spectroscopy and Single-Photon Emission Computed Tomography in the Evaluation of Cerebral Tumors: A Case Report

    PubMed Central

    Siasios, Ioannis; Valotassiou, Varvara; Kapsalaki, Eftychia; Tsougos, Ioannis; Georgoulias, Panagiotis; Fotiadou, Aggeliki; Ioannou, Maria; Koukoulis, Georgios; Dimopoulos, Vassilios; Fountas, Kostas

    2017-01-01

    In their daily clinical practice, physicians have to confront diagnostic dilemmas which cannot be resolved by the application of only one imaging technique. In this case report, we present a 66-year-old woman who was admitted to our institution for the surgical resection of a recently diagnosed brain tumor. The patient had a history of epileptic seizures and was hospitalized in the past for anti-phospholipid syndrome related to a non-Hodgkin lymphoma in remission. Magnetic resonance imaging (MRI) examination revealed an enhancing right parasagittal lesion with significant edema suggestive of a high grade glioma. Advanced MRI techniques including proton magnetic resonance spectroscopy (1H-MRS) showed findings compatible of glioma. An additional examination was performed as part of a protocol that we are routinely performing in our institution for all brain tumors including not only the gold standard advanced MRI techniques but also single-photon emission computed tomography (SPECT) with technetium-99m (Tc99m). Brain SPECT indicated the presence of a meningioma which was verified by the histopathology of the resected specimen. In conclusion, a multimodality approach for the pre-surgical assessment of brain tumors has significant advantages not only for the diagnosis but also for the evaluation of intracranial tumors histology. PMID:27924180

  12. Diagnostic accuracy of exercise thallium-201 single-photon emission computed tomography in patients with left bundle branch block

    SciTech Connect

    Larcos, G.; Gibbons, R.J.; Brown, M.L. )

    1991-09-15

    Recent reports have proposed that abnormal apical or anterior wall perfusion with exercise thallium-201 imaging may increase diagnostic accuracy for disease of the left anterior descending artery in patients with left bundle branch block (LBBB). To evaluate these suggestions, 83 patients with LBBB who underwent thallium-201 single-photon emission computed tomography and coronary angiography within an interval of 3 months were retrospectively reviewed. There were 59 men and 24 women aged 33 to 84 years (mean 65). Myocardial perfusion to the apex, anterior wall and anterior septum were scored qualitatively by consensus of 2 experienced observers and by quantitative analysis in comparison with a normal data base. The sensitivity, specificity and accuracy of perfusion defects in these segments were then expressed according to angiographic findings. Significant stenosis of vessels within the left anterior descending artery territory was present in 38 patients. By receiver-operator characteristic analysis, a fixed or reversible defect within the apex by the qualitative method was the best criterion for coronary artery disease. However, although highly sensitive (79 and 85% by the qualitative and quantitative methods, respectively), an apical defect was neither specific (38 and 16%, respectively), nor accurate (57 and 46%, respectively). Perfusion abnormalities in the anterior wall and septum were also of limited diagnostic accuracy. Thus, modified interpretative criteria in patients with LBBB are not clinically useful in the assessment of left anterior descending artery disease.

  13. Microcystic meningioma with late-phase accumulation on thallium-201 single-photon emission computed tomography: case report.

    PubMed

    Matano, Fumihiro; Adachi, Koji; Murai, Yasuo; Kitamura, Takayuki; Ohashi, Ryuji; Teramoto, Akira; Morita, Akio

    2014-01-01

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

  14. Predictors of positive thallium 201 single photon emission computed tomography in patients of end stage renal disease.

    PubMed

    Majeed, Irfan; Ayub, Muhammad; Abid, Abdul Rehman; Azhar, Muhammad

    2008-01-01

    To study coronary artery disease (CAD) risk factors predicting positive thallium-201 single photon emission computed tomography (SPECT) indicating underlying CAD among patients of end stage renal disease. PLACE AND DESIGN: This cross-sectional (analytical) study was done at Department of Cardiology, Punjab Institute of Cardiology, from April 2004 to Dec 2007. One hundred consecutive patients with ESRD undergoing thallium SPECT as a routine screening test before renal transplant were studied. Dipyridamole thallium SPECT was performed in patients who were unable to exercise. Thallium SPECT was positive in 47 (47%) cases. There were significant differences in age, underlying diabetic nephropathy and total cholesterol levels among patients positive and negative on thallium SPECT. Among the risk factors age and underlying diabetic nephropathy were significantly associated (p < 0.05) with a positive thallium SPECT in patients with ESRD. Positive thallium SPECT indicating underlying CAD was observed in a significant number of patients with ESRD awaiting renal transplant. Presence of advanced age and underlying diabetic nephropathy predict a positive thallium SPECT in this population.

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

    SciTech Connect

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

    1989-05-01

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

  16. Cilostazol improves symptomatic intracranial artery stenosis - Evaluation of cerebral blood flow with single photon emission computed tomography

    PubMed Central

    Kai, Yutaka; Watanabe, Masaki; Morioka, Motohiro; Hirano, Teruyuki; Yano, Shigetoshi; Ohmori, Yuki; Kawano, Takayuki; Hamada, Jun-Ichiro; Kuratsu, Jun-Ichi

    2011-01-01

    Background: To evaluate the effectiveness of cilostazol in patients with intracranial arterial stenosis, we used magnetic resonance angiography (MRA). The drug's effect on the cerebral blood flow (CBF) was examined by single photon emission computed tomography (SPECT). Methods: In this retrospective study, we evaluated the clinical outcomes of 20 patients with stenosis in the M1 segment of the middle cerebral artery (MCA) who had suffered ischemic stroke within 12 weeks or manifested asymptomatic stenosis exceeding 50%. All patients received cilostazol (100 mg twice daily). MRA and SPECT (at rest and after acetazolamide challenge) studies were performed before and 6 and 12 months after the start of cilostazol treatment. Results: In 5 patients the stenotic lesion showed improvement on MRA. Mean stenosis before cilostazol therapy was 71.7 ± 4.9%, which improved to 39.0 ± 3.2% at 6 months and to 27.2 ± 2.8% at 12 months. SPECT study showed that CBF was improved in 3 patients; in one there was improvement at rest and the other 2 manifested improvement upon acetazolamide challenge. Conclusions: Cilostazol had a remodeling effect on stenotic lesions due to arteriosclerotic changes and improved CBF in some patients. PMID:21297930

  17. Use of fuzzy edge single-photon emission computed tomography analysis in definite Alzheimer's disease - a retrospective study

    PubMed Central

    2010-01-01

    Background Definite Alzheimer's disease (AD) requires neuropathological confirmation. Single-photon emission computed tomography (SPECT) may enhance diagnostic accuracy, but due to restricted sensitivity and specificity, the role of SPECT is largely limited with regard to this purpose. Methods We propose a new method of SPECT data analysis. The method is based on a combination of parietal lobe selection (as regions-of-interest (ROI)), 3D fuzzy edge detection, and 3D watershed transformation. We applied the algorithm to three-dimensional SPECT images of human brains and compared the number of watershed regions inside the ROI between AD patients and controls. The Student's two-sample t-test was used for testing domain number equity in both groups. Results AD patients had a significantly reduced number of watershed regions compared to controls (p < 0.01). A sensitivity of 94.1% and specificity of 80% was obtained with a threshold value of 57.11 for the watershed domain number. The narrowing of the SPECT analysis to parietal regions leads to a substantial increase in both sensitivity and specificity. Conclusions Our non-invasive, relatively low-cost, and easy method can contribute to a more precise diagnosis of AD. PMID:20809946

  18. Characterization of simulated incident scatter and the impact on quantification in dedicated breast single-photon emission computed tomography

    PubMed Central

    Mann, Steve D.; Tornai, Martin P.

    2015-01-01

    Abstract. The objective was to characterize the changes seen from incident Monte Carlo-based scatter distributions in dedicated three-dimensional (3-D) breast single-photon emission computed tomography, with emphasis on the impact of scatter correction using the dual-energy window (DEW) method. Changes in scatter distributions with 3-D detector position were investigated for prone breast imaging with an ideal detector. Energy spectra within a high-energy scatter window measured from simulations were linearly fit, and the slope was used to characterize scatter distributions. The impact of detector position on the measured scatter fraction within various photopeak windows and the k value (ratio of scatter within the photopeak and scatter energy windows) useful for scatter correction was determined. Results indicate that application of a single k value with the DEW method in the presence of anisotropic object scatter distribution is not appropriate for trajectories including the heart and liver. The scatter spectra’s slope demonstrates a strong correlation to measured k values. Reconstructions of fixed-tilt 3-D acquisition trajectories with a single k value show quantification errors up to 5% compared to primary-only reconstructions. However, a variable-tilt trajectory provides improved sampling and minimizes quantification errors, and thus allows for a single k value to be used with the DEW method leading to more accurate quantification. PMID:26839906

  19. Comparison of deconvolution techniques using a distribution mixture parameter estimation: application in single photon emission computed tomography imagery

    NASA Astrophysics Data System (ADS)

    Mignotte, Max; Meunier, Jean; Soucy, Jean-Paul; Janicki, Christian

    2002-01-01

    Thanks to its ability to yield functionally rather than anatomically-based information, the single photon emission computed tomography (SPECT) imagery technique has become a great help in the diagnostic of cerebrovascular diseases which are the third most common cause of death in the USA and Europe. Nevertheless, SPECT images are very blurred and consequently their interpretation is difficult. In order to improve the spatial resolution of these images and then to facilitate their interpretation by the clinician, we propose to implement and to compare the effectiveness of different existing 'blind' or 'supervised' deconvolution methods. To this end, we present an accurate distribution mixture parameter estimation procedure which takes into account the diversity of the laws in the distribution mixture of a SPECT image. In our application, parameters of this distribution mixture are efficiently exploited in order to prevent overfitting of the noisy data for the iterative deconvolution techniques without regularization term, or to determine the exact support of the object to be restored when this one is needed. Recent blind deconvolution techniques such as the NAS--RIF algorithm, combined with this estimation procedure, can be efficiently applied in SPECT imagery and yield promising results.

  20. Variable activation of the DNA damage response pathways in patients undergoing single-photon emission computed tomography myocardial perfusion imaging.

    PubMed

    Lee, Won Hee; Nguyen, Patricia; Hu, Shijun; Liang, Grace; Ong, Sang-Ging; Han, Leng; Sanchez-Freire, Veronica; Lee, Andrew S; Vasanawala, Minal; Segall, George; Wu, Joseph C

    2015-02-01

    Although single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) has improved the diagnosis and risk stratification of patients with suspected coronary artery disease, it remains a primary source of low-dose radiation exposure for cardiac patients. To determine the biological effects of low-dose radiation from SPECT MPI, we measured the activation of the DNA damage response pathways using quantitative flow cytometry and single-cell gene expression profiling. Blood samples were collected from patients before and after SPECT MPI (n=63). Overall, analysis of all recruited patients showed no marked differences in the phosphorylation of proteins (H2AX, protein 53, and ataxia telangiectasia mutated) after SPECT. The majority of patients also had either downregulated or unchanged expression in DNA damage response genes at both 24 and 48 hours post-SPECT. Interestingly, a small subset of patients with increased phosphorylation had significant upregulation of genes associated with DNA damage, whereas those with no changes in phosphorylation had significant downregulation or no difference, suggesting that some patients may potentially be more sensitive to low-dose radiation exposure. Our findings showed that SPECT MPI resulted in a variable activation of the DNA damage response pathways. Although only a small subset of patients had increased protein phosphorylation and elevated gene expression postimaging, continued care should be taken to reduce radiation exposure to both the patients and operators. © 2015 American Heart Association, Inc.

  1. Standardization of techniques for using single-photon emission computed tomography (SPECT) for aerosol deposition assessment of orally inhaled products.

    PubMed

    Fleming, John; Bailey, Dale L; Chan, Hak-Kim; Conway, Joy; Kuehl, Philip J; Laube, Beth L; Newman, Stephen

    2012-12-01

    Single-photon emission computed tomography (SPECT) can be used to measure the three-dimensional (3D) distribution of inhaled aerosol deposition in the lungs. This is of value in evaluating and optimizing drug delivery by inhalation. 3D imaging has the advantage over planar scintigraphy of giving better data on the distribution of deposition within the lung. There are a variety of different methods of acquisition and analysis of the data, which makes interpretation of results difficult to compare between centers. This article describes a standardized protocol that aims to overcome this problem. Although not being completely prescriptive, it presents the key recommendations that are necessary to ensure consistency. In addition to radiolabel validation, these are (i) having some form of accountability of the activity measurements as quality control, (ii) producing quantitative images by performing attenuation and preferably scatter correction, (iii) defining volumes of interest and calculating parameters in the manner described, and (iv) describing in any report the details of technique used. When carefully used, SPECT imaging is able to produce high-quality quantitative data of the 3D distribution of drug deposition within the lungs. By establishing a standardized protocol, results of 3D imaging of the deposition of orally inhaled aerosols using SPECT should be more comparable, which should enhance collaborations between centers and insure that this form of imaging becomes acceptable to the regulatory authorities.

  2. Multimodal sentinel lymph node mapping with single-photon emission computed tomography (SPECT)/computed tomography (CT) and photoacoustic tomography.

    PubMed

    Akers, Walter J; Edwards, W Barry; Kim, Chulhong; Xu, Baogang; Erpelding, Todd N; Wang, Lihong V; Achilefu, Samuel

    2012-03-01

    The identification of cancer cells in the lymph nodes surrounding a tumor is important in establishing a prognosis. Optical detection techniques such as fluorescence and photoacoustic tomography (PAT) have been reported in preclinical studies for noninvasive sentinel lymph node (SLN) mapping. A method for validation of these techniques is needed for clinical trials. We report the use of a multimodal optical-radionuclear contrast agent as a validation tool for PAT in a preclinical model. Methylene blue (MB) was radiolabeled with (125)I for multimodal SLN mapping and used in conjunction with MB to assess the feasibility of multimodal SLN mapping in a rat model by PAT and single-photon emission computed tomography (SPECT). MB provided sufficient contrast for identifying SLNs noninvasively with a PAT system adapted from a clinical ultrasound imaging system. The signal location was corroborated by SPECT using (125)I labeled MB. The translation of PAT into the clinic can be facilitated by a direct comparison with established imaging methods using a clinically relevant dual SPECT and photoacoustic imaging agent. The new high-resolution PAT is a promising technology for the sensitive and accurate SLN detection in cancer patients. Copyright © 2012 Mosby, Inc. All rights reserved.

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

    PubMed Central

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

    2015-01-01

    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

  4. Hepatic clearance measured with (99m)Tc-GSA single-photon emission computed tomography to estimate liver fibrosis.

    PubMed

    Taniguchi, Masahiko; Okizaki, Atsutaka; Watanabe, Kenji; Imai, Koji; Uchida, Koichiro; Einama, Takahiro; Shuke, Noriyuki; Miyokawa, Naoyuki; Furukawa, Hiroyuki

    2014-11-28

    To evaluate the clinical utility of hepatic clearance (HC) measured with technetium-99m-diethylenetriaminepenta-acetic acid-galactosyl human serum albumin ((99m)Tc-GSA) single-photon emission computed tomography (SPECT) to estimate the degree of liver fibrosis. Seventy-eight consecutive patients who underwent initial hepatectomy due to hepatocellular carcinoma were enrolled in this study. Indocyanine green clearance (ICG R15), quantitative indices estimated by (99m)Tc-GSA [the receptor index (LHL15 and HH15) and HC via SPECT analysis], and conventional liver function tests were performed before hepatectomy. Correlations among the quantitative indices for liver functional reserve, conventional liver function tests, and the degree of liver fibrosis were evaluated. The degree of liver fibrosis was correlated with ICG R15, HH15, LHL15, and HC. HC showed the best correlation with conventional liver function tests. According to multivariate analysis, HC and LHL15 were significant independent predictors of severe fibrosis. HC was the most valuable index for predicting severe fibrosis. HC measured with (99m)Tc-GSA SPECT is a reliable index for assessing liver fibrosis before hepatectomy.

  5. Technetium-99m Methylene Diphosphonate Single-photon Emission Computed Tomography/Computed Tomography of the Foot and Ankle.

    PubMed

    Upadhyay, Bhavin; Mo, Jonathan; Beadsmoore, Clare; Marshall, Tom; Toms, Andoni; Buscombe, John

    2017-01-01

    The complex anatomy and function of the foot and ankle can make it difficult to determine the cause of symptoms in patients with foot and ankle pathology. Following initial clinical and radiographic assessment, additional imaging with magnetic resonance imaging may be required, which is often seen as the modality of choice. Although sensitive to pathological changes in bone metabolism and vascularity, technetium-99m (Tc-99m) bone scintigraphy often lacks the specificity and resolution required to evaluate the structures of the foot and ankle. Tc-99m methylene diphosphonate single-photon emission computed tomography/computed tomography (SPECT/CT) combines this sensitivity with the superior anatomical detail of CT, enabling better localization of pathological uptake and evaluation of associated structural changes. As a result, SPECT/CT has been growing in popularity for the assessment of patients with foot and ankle pathology where it can provide additional information that may change the initial diagnosis and subsequent management plan. Studies have reported modification of the surgical approach and site of intra-articular local anesthetic injections following SPECT/CT with good results. Interpretation of SPECT/CT studies requires an understanding of the pathological changes that result in increased tracer accumulation in addition to the CT changes that may be seen. This review aims to highlight the advantages of SPECT/CT, potential applications and explain the imaging appearances of common pathologies that may be observed.

  6. Stress scintigraphy using single-photon emission computed tomography in the evaluation of coronary artery disease

    SciTech Connect

    Nohara, R.; Kambara, H.; Suzuki, Y.; Tamaki, S.; Kadota, K.; Kawai, C.; Tamaki, N.; Torizuka, K.

    1984-05-01

    Twenty-seven patients with angina pectoris, 24 with postmyocardial infarction angina and 7 with normal coronary arteries were examined by exercise thallium-201 emission computed tomography (SPECT) and planar scintigraphy. Exercise SPECT was compared with the reperfusion imaging obtained approximately 2 to 3 hours after exercise. The sensitivity and specificity of demonstrating involved coronary arteries by identifying the locations of myocardial perfusion defects were 96 and 87% for right coronary artery, 88 and 89% for left anterior descending artery (LAD) and 78 and 100% for left circumflex artery (LC). These figures are higher than those for planar scintigraphy (85 and 87% for right coronary artery, 73 and 89% for LAD and 39 and 100% for LC arteries). In patients with 3-vessel disease, sensitivity of SPECT (100, 88 and 75% for right coronary artery, LAD and LC, respectively) was higher than planar imaging (88, 63 and 31%, respectively), with a significant difference for LC (p less than 0.05). In 1, 2 and 0-vessel disease the sensitivity and specificity of the 2 techniques were comparable. Multivessel disease was more easily identified as multiple coronary involvement than planar imaging with a significant difference in 3-vessel disease (p less than 0.05). In conclusion, stress SPECT provides useful information for the identification of LC lesions in coronary heart disease, including 3-vessel involvement.

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

    PubMed

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

    2015-10-27

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

  8. Single-photon property characterization of 1.3 μm emissions from InAs/GaAs quantum dots using silicon avalanche photodiodes

    PubMed Central

    Zhou, P. Y.; Dou, X. M.; Wu, X. F.; Ding, K.; Li, M. F.; Ni, H. Q.; Niu, Z. C.; Jiang, D. S.; Sun, B. Q.

    2014-01-01

    We developed a new approach to test the single-photon emissions of semiconductor quantum dots (QDs) in the optical communication band. A diamond-anvil cell pressure device was used for blue-shifting the 1.3 μm emissions of InAs/GaAs QDs to 0.9 μm for detection by silicon avalanche photodiodes. The obtained g(2)(0) values from the second-order autocorrelation function measurements of several QD emissions at 6.58 GPa were less than 0.3, indicating that this approach provides a convenient and efficient method of characterizing 1.3 μm single-photon source based on semiconductor materials. PMID:24407193

  9. Single-photon property characterization of 1.3 μm emissions from InAs/GaAs quantum dots using silicon avalanche photodiodes.

    PubMed

    Zhou, P Y; Dou, X M; Wu, X F; Ding, K; Li, M F; Ni, H Q; Niu, Z C; Jiang, D S; Sun, B Q

    2014-01-10

    We developed a new approach to test the single-photon emissions of semiconductor quantum dots (QDs) in the optical communication band. A diamond-anvil cell pressure device was used for blue-shifting the 1.3 μm emissions of InAs/GaAs QDs to 0.9 μm for detection by silicon avalanche photodiodes. The obtained g((2))(0) values from the second-order autocorrelation function measurements of several QD emissions at 6.58 GPa were less than 0.3, indicating that this approach provides a convenient and efficient method of characterizing 1.3 μm single-photon source based on semiconductor materials.

  10. The usefulness of combined brain perfusion single-photon emission computed tomography, Dopamine-transporter single-photon emission computed tomography, and (123) I-metaiodobenzylguanidine myocardial scintigraphy for the diagnosis of dementia with Lewy bodies.

    PubMed

    Kobayashi, Seiju; Makino, Kanae; Hatakeyama, Shigeki; Ishii, Takao; Tateno, Masaru; Iwamoto, Tomo; Tsujino, Hanako; Kawasaki, Kazuhito; Mikuni, Kouhei; Ukai, Wataru; Murayama, Tomonori; Hashimoto, Eri; Utsumi, Kumiko; Kawanishi, Chiaki

    2017-07-01

    Current diagnostic criteria recommend neuroimaging as a diagnostic support tool for the clinical diagnosis of dementia with Lewy bodies (DLB). Because DLB causes characteristic impairments and disabilities, such as neuroleptic hypersensitivity, which may significantly increase morbidity and mortality, its prompt and correct diagnosis is very important. The aim of this study was to evaluate the extent to which diagnostic accuracy can be increased by using different combinations of brain perfusion single-photon emission computed tomography (bp-SPECT), (123) I-metaiodobenzylguanidine myocardial scintigraphy (MIBG scintigraphy), and DAT-SPECT. Taking finances and patient burden into consideration, we compared the tests to determine priority. Thirty-four patients with probable DLB (75.0 ± 8.3 years old; 14 men, 20 women) underwent bp-SPECT, MIBG scintigraphy, and DAT-SPECT. Our comparison of three functional imaging techniques indicated that MIBG scintigraphy (79%) and Dopamine-transporter (DAT) SPECT (79%) had better sensitivity for characteristic abnormalities in DLB than bp-SPECT (53%). The combination of the three modalities could increase sensitivity for diagnosis of DLB to 100%. Additionally, the ratio of patients with rapid eye movement sleep behaviour disorder was significantly higher in the positive finding group on MIBG scintigraphy than in the negative finding group. In terms of stand-alone diagnostic means, priority should be placed on MIBG scintigraphy or DAT-SPECT for the diagnosis of DLB. However, our results suggest that the combination of bp-SPECT, MIBG scintigraphy, and DAT-SPECT increased the accuracy of the clinical diagnosis of DLB. © 2017 Japanese Psychogeriatric Society.

  11. 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

    SciTech Connect

    Yin Lingshu; Shcherbinin, Sergey; Celler, Anna

    2010-10-01

    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 V{sub 20} 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.

  12. Heart failure diagnostics based on ventilation/perfusion single photon emission computed tomography pattern and quantitative perfusion gradients.

    PubMed

    Jögi, Jonas; Palmer, John; Jonson, Björn; Bajc, Marika

    2008-08-01

    Left heart failure (LHF) is a common and frequently overlooked condition owing to insufficient diagnostic methods. This can potentially delay onset of treatment. Our clinical experience with ventilation/perfusion single photon emission computed tomography (V/P SPECT) indicates that perfusion shows an antigravitational distribution pattern in LHF. The aim of the study was to test the hypothesis that LHF diagnosis can be made on the basis of V/P SPECT, and to develop and perform a first evaluation of objective parameters for LHF diagnostics in terms of perfusion gradients. This retrospective study included 247 consecutive patients with clinical suspicion of pulmonary embolism (PE), who were examined with V/P SPECT. Perfusion gradients were developed and quantified in dorso-ventral and cranio-caudal directions. Quantitative results were compared with visual interpretation of patients with normal and heart failure patterns. Patients with LHF pattern were retrospectively followed up by review of medical records to confirm or discard heart failure diagnosis at the time of V/P SPECT examination. LHF pattern on V/P SPECT was identified in 36 patients (15%), normal ventilation/perfusion pattern was found in 67 patients (27%), and PE in 62 patients (25%). The follow-up confirmed heart failure diagnosis in 32 of the 36 cases with LHF pattern, leading to a positive predictive value of 88% for LHF diagnosis based on V/P SPECT. Dorso-ventral perfusion gradients discriminated normal from LHF patients. In patients with suspected PE, LHF is common. Appropriate V/P SPECT pattern recognition, supported by objectively determined dorso-ventral perfusion gradients, allows the diagnosis of LHF. A positive perfusion gradient in the dorso-ventral direction should lead to consideration of heart failure as a possible explanation for the symptoms in these patients.

  13. Alterations in myocardial thallium-201 distribution in patients with chronic systemic hypertension undergoing single-photon emission computed tomography

    SciTech Connect

    DePuey, E.G.; Guertler-Krawczynska, E.; Perkins, J.V.; Robbins, W.L.; Whelchel, J.D.; Clements, S.D.

    1988-08-01

    To characterize thallium-201 distribution in single-photon emission computed tomography (SPECT) cardiac images and polar bullseye maps, 100 patients with chronic systemic hypertension due to end-stage renal disease were studied and the results compared with those in 35 normotensive control subjects. Thallium-201 SPECT was performed after exercise in all control subjects and 70 hypertensive patients, and after intravenous dipyridamole in 30 patients. A frequent finding in hypertensive patients was a fixed decrease in the normal lateral-to-septal count density ratio in immediate thallium-201 SPECT images (1.02 +/- 0.10 vs 1.17 +/- 0.08 in control subjects, p less than 0.00001) and in 3-hour delayed images (1.02 +/- 0.11 vs 1.11 +/- 0.08 in control subjects, p less than 0.00001). No significant difference in count density ratio was present in patients undergoing treadmill versus diypridamole intervention. In 35 patients the count density ratio was greater than 2.0 standard deviations below the normal mean, creating the false impression of a fixed lateral defect (i.e., myocardial infarction). In 12 patients, myocardial wall thickness was measured at end-diastole by 2-dimensional echocardiography. Wall thickness was increased (greater than 11 mm) in all patients. The mean lateral-to-septal wall thickness ratio was 1.08 +/- 1.11; in no patient was the ratio less than 0.76 to indicate selective septal hypertrophy. The lateral-to-septal wall thickness and lateral-to-septal thallium-201 count density ratios correlated poorly (r = 0.43).

  14. Factors determining altered perfusion after acute pulmonary embolism assessed by quantified single-photon emission computed tomography-perfusion scan

    PubMed Central

    Meysman, Marc; Everaert, Hendrik; Vincken, Walter

    2017-01-01

    AIM OF THE STUDY: The aim of the study was to analyze the evolution of perfusion (Q)-defects in patients treated for acute pulmonary embolism (PE), correlation with baseline parameters and evaluation of recurrence risk. METHODS: This is a single-center prospective observational cohort study in symptomatic normotensive PE. Comparison of the ventilation/perfusion single-photon emission computed tomography (V/Q-SPECT) acquired at baseline with a quantified SPECT (Q-SPECT) repeated at 1 week and 6 months. The Q-defect extent (percentage of total lung volume affected) was measured semiquantitatively. Data collected at baseline were age, gender, body mass index (BMI), history of previous venous thromboembolism (HVTE), Charlson's Comorbidity Score (CcS), plasma troponin-T and D-dimer levels, PE Severity Index, and tricuspid regurgitation jet (TRJ) velocity. RESULTS: Forty-six patients (22 men/24 women, mean age 61.7 years (± standard deviation 16.3)) completed the study. At 1 week, 13/46 (28.3 %) and at 6 months 22/46 (47.8%) patients had completely normalized Q-SPECT. Persistence of Q-defects was more frequent in female patients in univariate and multivariate analysis. We found no correlation between the persistence of Q-defects on Q-SPECT and HVTE, BMI, plasma troponin-T, and CcS. However, lower TRJ and younger age were statistically significantly linked to normalization of Q-scans after 6 months of treatment only in univariate analysis. There is no difference in the frequency of recurrent PE in relation to the persistence of Q-defects. CONCLUSION: Acute PE patients of female, older age, and higher TRJ in univariate analysis and patients of female in multivariate analysis seem to have a higher risk of persistent Q-defects after 6 months treatment. The presence of residual Q-abnormalities at 6 months was not associated with an increased risk for recurrent PE. PMID:28197219

  15. The value of combining single photon emission computerised tomography and computerised tomography in the investigation of spondylolysis.

    PubMed

    Gregory, P L; Batt, M E; Kerslake, R W; Scammell, B E; Webb, J F

    2004-10-01

    The aim of this study was to assess the diagnostic value of combining single photon emission computerised tomography (SPECT) with reverse gantry computerised tomography (rg-CT) in the investigation of spondylolysis. Patient characteristics and imaging results in 118 patients, aged 8-44 years, with low back pain (LBP) were analysed. SPECT showed increased scintigraphic uptake in 80 patients, and spondylolysis was identified on rg-CT in 53. The Cohen Kappa ratio of 0.362 (95% CI: 0.198-0.526) suggests only fair agreement for the result of increased scintigraphic activity with the finding of spondylolysis on rg-CT. We conclude that these investigations give mutually exclusive information, which leads to four diagnostic categories. When there was increased scintigraphic activity on SPECT, 58.8% (95% CI: 48.0-69.5%) of patients had spondylolysis on rg-CT. With rest from provoking activities, these lesions may heal. We interpret the findings of increased scintigraphic activity, but no spondylolysis demonstrated on rg-CT as indicating a bone stress response. These also require rest from provoking activity to prevent a stress fracture developing. In this study, 84.2% (95% CI: 72.67-95.8%) of those patients without increased activity on SPECT had no spondylolysis identified on rg-CT. These patients may need further investigations such as magnetic resonance imaging (MRI) to diagnose pathology, which typically does not involve the posterior elements--but rest from sport may not be so important. There were five patients in our study, without increased scintigraphic activity, but in whom bilateral chronic-appearing (wide separation, smooth sclerotic bone margins) spondylolyses were identified at L5. These all were anticipated from previous plain radiographs or MRI. This group will almost certainly not heal, and if the spondylolyses are the cause of pain these vertebrae will need stabilisation by surgery if physiotherapy fails.

  16. Assessment of left ventricular diastolic function by gated single-photon emission tomography: comparison with Doppler echocardiography.

    PubMed

    Yamano, Tetsuhiro; Nakamura, Tomoki; Sakamoto, Kenzo; Hikosaka, Takato; Zen, Kan; Nakamura, Takeshi; Sawada, Takahisa; Azuma, Akihiro; Nishimura, Tsunehiko; Nakagawa, Masao

    2003-11-01

    Gated single-photon emission tomography (SPET) is not yet an established procedure for the evaluation of left ventricular (LV) diastolic function. This study examined diastolic function derived from gated SPET in comparison with an established diagnostic tool, Doppler echocardiography. We examined 37 consecutive patients with normal sinus rhythm who underwent gated technetium-99m tetrofosmin SPET. A gated SPET program was used with a temporal resolution of 32 frames per R-R interval. We obtained the Doppler transmitral flow velocity waveform immediately before gated SPET image acquisition. Patients who showed a ratio of peak early transmitral flow velocity to atrial flow velocity (E/A) of >1 or whose R-R intervals differed by >5% between Doppler echocardiography and gated SPET were excluded from this investigation. We compared diastolic indices and presumed corresponding intervals in diastole using the two methods. The peak filling rate (PFR) derived from gated SPET correlated with the Doppler peak velocity of the early transmitral flow (E) wave ( r=0.65) and deceleration of the E wave ( r=0.71). The time to PFR and percent atrial contribution to LV filling from gated SPET correlated excellently with the Doppler LV isovolumic relaxation time ( r=0.93) and the E/A ratio ( r=-0.85), respectively. There was a significant linear correlation in all the intervals from the R wave to the presumed corresponding diastolic points. The point of PFR in gated SPET and the peak of the E wave in Doppler echocardiography generally coincided. The onset of filling in gated SPET tended to be closer to the second heart sound than the start of the E wave in Doppler echocardiography. We conclude that gated SPET permits the assessment of not only myocardial perfusion and LV systolic function but also diastolic function, although there may be some errors in detection of the precise beginning of LV filling.

  17. Prediction of Cognitive Decline from White Matter Hyperintensity and Single-Photon Emission Computed Tomography in Alzheimer's Disease.

    PubMed

    Tabei, Ken-Ichi; Kida, Hirotaka; Hosoya, Tetsuo; Satoh, Masayuki; Tomimoto, Hidekazu

    2017-01-01

    While several studies support an association of white matter hyperintensity (WMH) volume and regional cerebral blood flow (rCBF) with cognitive decline in Alzheimer's disease (AD), no reports have simultaneously considered the effects of both factors on cognitive decline. The purpose of the present study was to compare WMH volume and rCBF in relation to cognitive function by developing a new software program to fuse magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) data. We used MRI, SPECT, and neuropsychological data from 182 serial outpatients treated at the memory clinic of our hospital. Twenty-nine AD patients fulfilled the inclusion criteria (18 females, mean age: 73.1 ± 7.9 years, mean Mini-Mental State Examination: 23.1 ± 3.0). Analysis of variance revealed that posterior deep WMH (DWMH) volume was significantly larger than both anterior periventricular hyperintensity (PVH) and DWMH, and posterior PVH volumes. Multivariate regression analysis showed that increased volumes of the anterior PVH and the posterior DWMH and decreased rCBF of the parietal cortex negatively affected cognitive function. The other areas had no significant negative effects on cognitive function. Our findings show that the volume of the posterior WMH was significantly larger than that of other areas, and the increased posterior WMH volume and decreased rCBF of the parietal cortex negatively affected cognitive function. Therefore, the posterior WMH volume and the parietal rCBF are key parameters of cognitive decline in AD patients.

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

    PubMed

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

    2015-12-01

    To assess whether global and regional myocardial strains from three-dimensional speckle tracking echocardiography (3D-STE) correlate with myocardial infarction size (MIS) detected by single photon emission computed tomography (SPECT). Fifty-seven patients with a history of ST-segment elevation myocardial infarction (MI) within 3-6 months were enrolled, alongside 24 healthy volunteers. Left ventricular (LV) global area strain, global longitudinal strain (GLS), global radial strain, global circumferential strain, left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) were measured and compared with the corresponding SPECT-detected MISs. Patients were sub-grouped into massive MIS group (MIS ≥ 12%) and small MIS group (MIS < 12%). Myocardial strains of all the LV segments were compared with the corresponding MIS. Global myocardial strain parameters, LVEF and WMSI of the patients were significantly different from the control group (all P < 0.05) and correlated well with MISs, most significantly for GLS (r = 0.728, P < 0.01). Significant differences in myocardial strain parameters were found between the massive and small MIS groups (all P < 0.05). Receiver operating characteristic curve analysis indicated that GLS had a highest diagnostic value and when the cutoff was -13.8%, the area under the curve was 0.84, with the 70.6% sensitivity and 87.5% specificity. Significant differences of myocardial strain parameters were observed between segments with and without transmural MIs (P < 0.01). 3D-STE myocardial strain parameters evaluated LV global MIS, 3D GLS had the highest diagnostic value. It also preliminarily gauged the degree of ischemia and necrosis of regional myocardial segments.

  19. Chronic thromboembolic pulmonary hypertension: Comparison of dual-energy computed tomography and single photon emission computed tomography in canines.

    PubMed

    Tang, Chun Xiang; Yang, Gui Fen; Schoepf, U Joseph; Han, Zong Hong; Qi, Li; Zhao, Yan E; Wu, Jiang; Zhou, Chang Sheng; Zhu, Hong; Stubenrauch, Andrew C; Mangold, Stefanie; Zhang, Long Jiang; Lu, Guang Ming

    2016-02-01

    To compare diagnostic accuracy between dual-energy CT lung perfused blood volume (Lung PBV) imaging and single photon emission computed tomography (SPECT) in detecting chronic thromboembolic pulmonary hypertension (CTEPH) with histopathological results as reference standard in a canine model. Eighteen CTEPH canines were included into this experimental study. All procedures including paracentesis, embolization, scanning, pressure measurement and feeding medicine were repeated each two weeks, until systolic/diastolic pressure in canines was ≥ 30/15 mm Hg or mean pulmonary artery pressure ≥ 20 mm Hg, and then sacrificed for histopathology examination. Two radiologists (readers 1 and 2) and two nuclear radiologists (readers 3 and 4) analyzed images of conventional CT pulmonary angiography in dual-energy CT mode, Lung PBV imaging and SPECT, respectively. The presence, numbers, and locations of pulmonary emboli (PE) were recorded on a per-lobe basis. Pathological examination was served as reference standard. Sensitivity, specificity and accuracy of Lung PBV and SPECT were calculated. Kappa statistics were used to quantify inter-reader agreement. With histopathological results as reference standard, the sensitivities of 72.2%, 78.8%, 81.2%, specificities of 75.9%, 87.5%, 84.8%, accuracies of 73.8%, 83.1%, 83.1%, for readers 1, 2 and both with Lung PBV, respectively. Readers 3, 4 and both had sensitivities of 14.3%, 25.7%, 33.3%, specificities of 90.0%, 86.7%, 93.3%, accuracies of 49.2%, 53.8%, 60.0% with SPECT for detecting CTEPH. Inter-reader agreements were good for dual-energy CT (kappa=0.662) and SPECT (k=0.706) for detecting CTEPH. Dual-energy CT had a higher accuracy to detect CTEPH than SPECT in this canine model study. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Quality of brain perfusion single-photon emission tomography images: multicentre evaluation using an anatomically accurate three-dimensional phantom.

    PubMed

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

    1998-10-01

    The aim of the study was to evaluate the quality of routine brain perfusion single-photon emission tomography (SPET) images in Finnish nuclear medicine laboratories. Twelve laboratories participated in the study. A three-dimensional high resolution brain phantom (Data Spectrum's 3D Hoffman Brain Phantom) was filled with a well-mixed solution of technetium-99m (110 MBq), water and detergent. Acquisition, reconstruction and printing were performed according to the clinical routine in each centre. Three nuclear medicine specialists blindly evaluated all image sets. The results were ranked from 1 to 5 (poor quality-high quality). Also a SPET performance phantom (Nuclear Associates' PET/SPECT Performance Phantom PS 101) was filled with the same radioactivity concentration as the brain phantom. The parameters for the acquisition, the reconstruction and the printing were exactly the same as with the brain phantom. The number of detected "hot" (from 0 to 8) and "cold" lesions (from 0 to 7) was visually evaluated from hard copies. Resolution and contrast were quantified from digital images. Average score for brain phantom images was 2.7 +/- 0.8 (range 1.5-4.5). The average diameter of the "hot" cylinders detected was 16 mm (range 9.2-20.0 mm) and that of the "cold" cylinders detected, 11 mm (5.9-14.3 mm) according to visual evaluation. Quantification of digital images showed that the hard copy was one reason for low-quality images. The quality of the hard copies was good only in four laboratories and was amazingly low in the others when comparing it with the actual structure of the brain phantom. The described quantification method is suitable for optimizing resolution and contrast detectability of hard copies. This study revealed the urgent need for external quality assurance of clinical brain perfusion SPET images.

  1. Quantitative exercise thallium-201 single photon emission computed tomography for the enhanced diagnosis of ischemic heart disease

    SciTech Connect

    Mahmarian, J.J.; Boyce, T.M.; Goldberg, R.K.; Cocanougher, M.K.; Roberts, R.; Verani, M.S. )

    1990-02-01

    The clinical utility of exercise thallium-201 single photon emission computed tomography was investigated in 360 consecutive patients who had concomitant coronary arteriography. Tomographic images were assessed visually and from computer-quantified polar maps. Sensitivity for detecting coronary artery disease was comparably high using quantitative and visual analysis, although specificity tended to improve using the former method (87% versus 76%, p = 0.09). Quantitative analysis was superior to the visual method for identifying left anterior descending (81% versus 68%, p less than 0.05) and circumflex coronary artery (77% versus 60%, p less than 0.05) stenoses and detected most patients (92%) with multivessel coronary artery disease. Multivessel involvement was correctly predicted in 65% of the patients with more than one critically stenosed vessel. Exercise variables in patients with significant coronary artery disease were similar whether the tomographic images were normal or abnormal. However, patients with coronary stenoses and normal versus abnormal tomograms had a trend toward more single vessel disease (79% versus 62%, p = 0.07) and moderate coronary stenosis (66% versus 28%, p less than 0.001), but had less proximal left anterior descending artery involvement (8% versus 34%, p = 0.05). Computer-quantified perfusion defect size was directly related to the extent of coronary artery disease. Intra- and interobserver agreement for quantifying defects were excellent (r = 0.98 and 0.97, respectively). In conclusion, quantitative thallium-201 tomography offers improved detection of coronary artery disease, localization of the anatomic site of coronary stenosis, prediction of multivessel involvement and accurate determination of perfusion defect size, while maintaining a high specificity.

  2. Tetrofosmin early time gated post-stress single-photon emission computed tomography imaging: feasibility and potential benefits.

    PubMed

    Philippe, Laurent; Mérino, Bertrand; Blaire, Tanguy; Bailliez, Alban; Casset-Senon, Danielle; Levy, Maurice; Halley, Arnaud; Divry, Guillaume

    2011-02-01

    The purpose of this study is to evaluate the feasibility, the image quality, and the clinical relevance of an early gated post-stress (GPS) single-photon emission computed tomography (SPECT) tetrofosmin (Myoview™-GE Healthcare) acquisition protocol. Time delay between myocardial technetium-labeled tracer administration and SPECT acquisition is usually about 30 minutes after stress, and 45 to 60 minutes at rest: because of the absence of significant redistribution, perfusion images are related to stress even 30 minutes after stress injection, while function and thickening data obtained with gated acquisition 30 minutes after stress are mainly related to rest conditions. 194 patients were prospectively included and analyzed, in a multicenter registry. Three gated-SPECT 99(m)Tc-Tetrofosmin studies were performed per patient: GPS-SPECT, 30 minutes post-stress (GS30), and at rest (GR30). GPS image quality was excellent/good (93.9%), and similar to GS30 images (96.6%). The presence of adjacent myocardial sub-diaphragmatic activity on GPS images was similar to GS30 images (24% vs 22%), and less frequent than on GR30 images (31%). For perfusion, thickening, and motion scores, there was no significant difference between early and 30 minute post-stress in the global patient population, but significant differences were observed between GPS and GS30 for LVEF (65% ± 15% vs 63% ± 14%). In the ischemic patients, with the stress-rest protocol, the perfusion score was 14.2 on GPS images and 12.4 on GS30 images (P = .002). Tetrofosmin early GPS-SPECT is feasible without impairment of image quality (better count rate). Ischemic defect size on early post-stress images is slightly more pronounced than at 30 minutes: this could modify therapeutic decision. This technique produces reliable function information during early post-stress period, and might be useful for disclosing transient motion abnormalities.

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

    SciTech Connect

    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.

  4. Incremental value of single-photon emission computed tomography/computed tomography in the diagnosis of active condylar hyperplasia.

    PubMed

    Agarwal, Krishan Kant; Mukherjee, Anirban; St, ArunRaj; Tripathi, Madhavi; Bal, Chandrasekhar

    2017-01-01

    To evaluate the incremental value of technetium-99m methylene diphosphonate (Tc-MDP) single-photon emission computed tomography/computed tomography (SPECT/CT) over planar bone scintigraphy (BS) and SPECT for the diagnosis of active condylar hyperplasia (CH). Data of 21 patients (mean age: 21.9±5.3 years, 10 males, 11 females) who underwent Tc-MDP BS along with regional SPECT/CT for the diagnosis of active CH were retrospectively evaluated. Planar BS, SPECT, and SPECT/CT images were evaluated by two nuclear medicine physician in consensus. Radioactive counts were measured per region of interest and the respective ratios were calculated. A percentage of condylar uptake 55% or higher, generating differences of 10% or more between condyles, was considered to be indicative of active unilateral condylar hyperactivity. Sensitivity, specificity, and positive and negative predictive values were calculated separately for planar BS, SPECT, and SPECT/CT. Clinical/imaging follow-up and histopathology was considered the reference standard. Planar BS, SPECT, and SPECT-CT of 21 patients with suspected CH were retrospectively evaluated. Planar BS was positive in eight patients, of whom six had active CH as the final diagnosis. SPECT was positive in 14 patients, of whom 12 patients had CH. Out of 14 patients who were positive in SPECT, two patients were considered negative in SPECT-CT. The diagnostic accuracy was the lowest for planar BS (47.6%) and the highest for SPECT/CT (85.8%). SPECT/CT and SPECT had similar sensitivity (80%), whereas SPECT-CT had the highest specificity (100%). SPECT/CT is superior to planar BS and SPECT for the diagnosis of active CH.

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

    PubMed

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

    2016-01-01

    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. 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 (99m)Tc 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. 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.

  6. Normal range of osteoblastic activity in total hip arthroplasties on single-photon emission computed tomography bone scintigraphy.

    PubMed

    Jin, Senpei; Boktor, Raef R; Kc Man, Kenneth; Pitman, Alexander G

    2016-09-01

    Knowledge of the normal range of periprosthetic osteoblastic activity around total hip arthroplasties is required for rational diagnosis of complications. The aim of this study was to establish such a normal range for single-photon emission computed tomography (SPECT). Clinical utility of such a range is confident differentiation of normal from abnormal arthroplasties. A total of 122 asymptomatic acetabular cups (age: 0-22 years) and 71 femoral stems (age: 0-20 years) were scanned with SPECT/CT. Two acetabular and three femoral activity ratios to normal reference bone were defined [acetabular axial (AA/RA), acetabular coronal (AC/RA), RA=reference acetabulum; femoral calcar (FC/RF), femoral mid-stem (FM/RF), femoral stem tip (FS/RF), RF=reference femur]. Upper cut-off of normal was defined as mean +3 SD (rounded). Two time breakpoints were analysed (12 and 24 months). The upper cut-off for the normal range was 1.0 for AA/RA, 1.5 for AC/RA and 2.2 for all thee of FC/RF, FM/RF and FS/RF. AA/RA, FM/RF and FS/RF showed no statistically significant temporal trends. AC/RA showed stabilization of activity after 12 months and FC/RF after 24 months. Measured activity ratios that fall within our normal range are likely to represent normal periprosthetic osteoblastic activity. Measured activity ratios that fall above the upper cut-offs of our normal range are likely to be abnormal. The cut-offs are robust in clinical practice and have utility in discriminating normal from abnormal stabilized arthroplasties where visual interpretation is ambiguous. Elevated AC/RA under 12 months and FC/RF under 24 months may represent normal periprosthetic activity and should be interpreted with caution.

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

    PubMed Central

    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. Brain areas involved in acupuncture needling sensation of de qi: a single-photon emission computed tomography (SPECT) study.

    PubMed

    Chen, Jia-Rong; Li, Gan-Long; Zhang, Gui-Feng; Huang, Yong; Wang, Shu-Xia; Lu, Na

    2012-12-01

    De qi is a sensory response elicited by acupuncture stimulation. According to traditional Chinese medicine (TCM), de qi is essential for clinical efficacy. However, the understanding of the neurobiological basis of de qi is still limited. To investigate the relationship between brain activation and de qi by taking a single-photon emission computed tomography (SPECT) scan while applying acupuncture at TE5. A total of 24 volunteers were randomly divided into 4 groups, and received verum or sham acupuncture at true acupuncture point TE5 or a nearby sham point according to grouping. All subjects then received a (99m)Tc-ethylcysteinate dimer (ECD) SPECT scan. All six subjects in the verum acupuncture at true acupuncture point group experienced de qi sensation; in contrast, all six subjects in the sham acupuncture at the sham point group responded with nothing other than non-sensation. Compared to the scan results from subjects who experienced non-sensation, SPECT scans from subjects with de qi sensation demonstrated significant activated points mainly located in brodmann areas 6, 8, 19, 21, 28, 33, 35, 37, 47, the parahippocampal gyrus, lentiform nucleus, claustrum and red nucleus; deactivated points were seen in brodmann areas 9 and 25. Verum acupuncture at true acupuncture points is more likely to elicit de qi sensation. De qi sensations mainly resulted in brain area activations, but not deactivations. These brain areas are related to the curative effect of Te5. The acupuncture needle sensations of de qi and sharp pain are associated with different patterns of activations and deactivations in the brain.

  9. [Specific features of interpretation of myocardial perfusion single-photon emission computed tomography with computed tomographic absorption correction].

    PubMed

    Ansheles, A A

    2014-01-01

    To study the capabilities of a hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) system during myocardial perfusion imaging study, to evaluate the impact of absorption correction (AC), and to reveal factors influencing the contribution of AC to the diagnostic result of the study. The study included 167 patients who underwent myocardial perfusion SPECT with and without CT AC. Differences between AC and non-AC studies were visually analyzed; the results of the analysis were used to form groups of visual differences. The supposed factors influencing the contribution of AC were studied, by assigning visual differences to a particular group. The possible variants of the impact of AC were described in the baseline scintigrams. AC made a significant contribution in 68% of cases. With AC, the perfusion defects visible during non-AC study recovered in 80% of these cases. The factors predicting substantial differences between the AC and non-AC studies included weight, end diastolic volume, male sex, patients with small focal perfusion defects and transient ischemia, and inadequate injected activity. Factors, such as body mass index, large perfusion defects, CT subsystem and orbit settings, and time from the injection of a radiotracer to the initiation of a study, had no substantial impact on the contribution of AC. During AC studies, SRS and transient ischemic dilatation were significantly higher than during non-AC studies, requiring a shift of standard criteria. There were some methodical features of interpretation of myocardial perfusion SPECT using CT correction. Myocardial SPECT with AC enhances the diagnostic value of the technique, simplifies the interpretation of myocardial perfusion SPECT, and reduces the number of false-positive and questionable results.

  10. Criteria for the addition of prone imaging to myocardial perfusion single-photon emission computed tomography for inferior wall.

    PubMed

    Nakaya, Koji; Onoguchi, Masahisa; Nishimura, Yoshihiro; Kiso, Keisuke; Otsuka, Hideki; Nouno, Yoshifumi; Shibutani, Takayuki; Yasuda, Eisuke

    2017-09-01

    Myocardial perfusion single-photon emission computed tomography (SPECT) is occasionally suspected to generate images that represent either ischemia or infarction for the inferior wall [right coronary artery (RCA) disease] or attenuation artifacts because of the diaphragm. We often encounter this. The application of prone imaging is advantageous in the differentiation of RCA disease because of attenuation artifacts. If decreased accumulation of radioisotopes is observed at the site with either RCA disease or attenuation artifacts, then a criterion that enables the addition of prone imaging should be implemented. Then, we evaluated sites where RCA disease and attenuation artifacts would likely appear and investigated the threshold of decreased accumulation that enables utilization of prone imaging. The patients in this study were divided into two groups: group A (20 patients) suspected to have attenuation artifacts because of the diaphragm and group B (14 patients) with RCA disease. Additional evaluation by prone imaging was performed in all patients. We utilized a 20-segment quantitative perfusion SPECT polar map in the supine and prone positions to compare the percentage increase in Thallium chloride (Tl) in both groups. We then investigated the percent uptake (%uptake) value of decreased accumulation in the inferior wall for the addition of prone imaging. The highest %uptake was present in segments 3, 4, 5, and 10 in group A after the prone imaging. Detection of attenuation artifacts from the diaphragm was easy in segments 3, 4, 5, and 10, and we set the %uptake threshold at 62, 61, 71, and 76%, respectively, in the supine position for the addition of prone imaging. A decrease of the %uptake in segments 3, 4, 5, and 10 after supine imaging is presumed to result from attenuation artifact or RCA disease. We established evaluation criteria for the addition of prone imaging in patients with decreased accumulation in the inferior wall during supine imaging.

  11. Single-photon emission of InAs/InP quantum dashes at 1.55 μm and temperatures up to 80 K

    SciTech Connect

    Dusanowski, Ł. Syperek, M.; Misiewicz, J.; Sęk, G.; Somers, A.; Kamp, M.; Höfling, S.; Reithmaier, J. P.

    2016-04-18

    We report on single photon emission from a self-assembled InAs/InGaAlAs/InP quantum dash emitting at 1.55 μm at the elevated temperatures. The photon auto-correlation histograms of the emission from a charged exciton indicate clear antibunching dips with as-measured g{sup (2)}(0) values significantly below 0.5 recorded at temperatures up to 80 K. It proves that the charged exciton complex in a single quantum dash of the mature InP-based material system can act as a true single photon source up to at least liquid nitrogen temperature. This demonstrates the huge potential of InAs on InP nanostructures as the non-classical light emitters for long-distance fiber-based secure communication technologies.

  12. Blue single photon emission up to 200 K from an InGaN quantum dot in AlGaN nanowire

    NASA Astrophysics Data System (ADS)

    Deshpande, Saniya; Das, Ayan; Bhattacharya, Pallab

    2013-04-01

    We demonstrate polarized blue single photon emission up to 200 K from an In0.2Ga0.8N quantum dot in a single Al0.1Ga0.9N nanowire. The InGaN/AlGaN dot-in-nanowire heterostructure was grown on (111) silicon by plasma assisted molecular beam epitaxy. Nanowires dispersed on a silicon substrate show sharp exciton and biexciton transitions in the micro-photoluminescence spectra. Second-order correlation measurements performed under pulsed excitation at the biexciton wavelength confirm single photon emission, with a g(2)(0) of 0.43 at 200 K. The emitted photons have a short radiative lifetime of 0.7 ns and are linearly polarized along the c-axis of the nanowire with a degree of polarization of 78%.

  13. Use of single-photon emission computed tomography/low-resolution computed tomography fusion imaging in detecting an unusually presenting osteoid osteoma of the lumbar vertebra.

    PubMed

    Hephzibah, Julie; Theodore, Bernice; Oommen, Regi; David, Kenny; Moses, Vinu; Shah, Sanjeev; Panicker, Jayalakshmi

    2009-03-01

    In this article, we describe an unusual presentation of osteoid osteoma of the lumbar vertebra in a woman in her early 30s. Single-photon emission computed tomography/low-resolution computed tomography (SPECT/CT) fusion imaging was used to detect the osteoma, precisely localize the pathology site, and guide surgical excision of the lesion. In recent years, SPECT/CT fusion imaging has helped make interpretations of scintigraphic images significantly more accurate.

  14. 99mTc-methylene diphosphonate single-photon emission computed tomography/computed tomography improves the diagnostic accuracy of osteoid osteoma

    PubMed Central

    Squier, Samuel Brian; Lewis, Jacob Ian; Accurso, Joseph Matthew; Jain, Manoj Kumar

    2016-01-01

    We present a case of a 17-year-old football player who had previously received multiple facet joint injections for presumed secondary osteoarthritis. 99mTc-methylene diphosphonate single-photon emission computed tomography/computed tomography imaging of the cervical spine demonstrated focal increased radiopharmaceutical activity in the right C2 lamina, which was associated with an osteolytic lesion with a central irregular sclerotic nidus. Surgical pathology confirmed an osteoid osteoma. PMID:27833319

  15. Hepatocellular carcinoma with intra-atrial tumor extension identified on 99mTc-labeled macroaggregated albumin single photon emission computed tomography/computed tomography

    PubMed Central

    Chandra, Piyush; Shah, Sneha; Purandare, Nilendu; Agrawal, Archi; Rangarajan, Venkatesh

    2016-01-01

    99mTc macroaggregated albumin (MAA) scintigraphy is always performed before administration of 90Y--microspheres for the treatment of liver tumors for hepatopulmonary shunt calculation. Tumor thrombus visualization in the hepatic vasculature is an infrequent finding on the 99m Tc--MAA single photon emission computed tomography. We present a rare case of a hepatocellular carcinoma extending as a tumor thrombus through hepatic vein, inferior vena cava into the right atrium. PMID:27833324

  16. Improved diagnostic performance of exercise thallium-201 single photon emission computed tomography over planar imaging in the diagnosis of coronary artery disease: a receiver operating characteristic analysis

    SciTech Connect

    Fintel, D.J.; Links, J.M.; Brinker, J.A.; Frank, T.L.; Parker, M.; Becker, L.C.

    1989-03-01

    Qualitative interpretation of tomographic and planar scintigrams, a five point rating scale and receiver operating characteristic analysis were utilized to compare single photon emission computed tomography and conventional planar imaging of myocardial thallium-201 uptake in the accuracy of the diagnosis of coronary artery disease and individual vessel involvement. One hundred twelve patients undergoing cardiac catheterization and 23 normal volunteers performed symptom-limited treadmill exercise, followed by stress and redistribution imaging by both tomographic and planar techniques, with the order determined randomly. Paired receiver operating characteristic curves revealed that single photon emission computed tomography was more accurate than planar imaging over the entire range of decision thresholds for the overall detection and exclusion of coronary artery disease and involvement of the left anterior descending and left circumflex coronary arteries. Tomography offered relatively greater advantages in male patients and in patients with milder forms of coronary artery disease, who had no prior myocardial infarction, only single vessel involvement or no lesion greater than or equal to 50 to 69%. Tomography did not appear to provide improved diagnosis in women or in detection of disease in the right coronary artery. Although overall detection of coronary artery disease was not improved in patients with prior myocardial infarction, tomography provided improved identification of normal and abnormal vascular regions. These results indicate that single photon emission computed tomography provides improved diagnostic performance compared with planar imaging in many clinical subgroups.

  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

    SciTech Connect

    Weinberger, D.R.; Gibson, R.; Coppola, R.; Jones, D.W.; Molchan, S.; Sunderland, T.; Berman, K.F.; Reba, R.C. )

    1991-02-01

    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

    PubMed Central

    Sharma, Punit; Jain, Tarun Kumar; Reddy, Rama Mohan; Faizi, Nauroze Ashgar; Bal, Chandrasekhar; Malhotra, Arun; Kumar, Rakesh

    2014-01-01

    Purpose: 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. Materials and Methods: 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. Results: 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%). Conclusion: 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. PMID:24591778

  19. The role of single-photon emission computed tomography/computed tomography in benign and malignant bone disease.

    PubMed

    Horger, Marius; Bares, Roland

    2006-10-01

    Radiological (plain radiographs, computed tomography [CT], magnetic resonance imaging [MRI]) and nuclear medicine methods (bone scan, leukocyte scan) both provide unique information about the status of the skeleton. Both have typical strengths and weaknesses, which often lead to the sequential use of different procedures in daily routine. This use causes the unnecessary loss of time and sometimes money, if redundant information is obtained without establishing a final diagnosis. Recently, new devices for hybrid imaging (single-photon emission computed tomography/computed tomography [SPECT/CT], positron emission tomography/computed tomography [PET/CT]) were introduced, which allow for direct fusion of morphological (CT) and functional (SPECT, PET) data sets. With regard to skeletal abnormalities, this approach appears to be extremely useful because it combines the advantages of both techniques (high-resolution imaging of bone morphology and high sensitivity imaging of bone metabolism). By the accurate correlation of both, a new quality of bone imaging has now become accessible. Although researchers undertaking the initial studies exclusively used low-dose CT equipment, a new generation of SPECT/CT devices has emerged recently. By integrating high-resolution spiral CT, quality of bone imaging may improve once more. Ongoing prospective studies will have to show whether completely new diagnostic algorithms will come up for classification of bone disease as a consequence of this development. Besides, the role of ultrasonography and MRI for bone and soft-tissue imaging also will have to be re-evaluated. Looking at the final aim of all imaging techniques--to achieve correct diagnosis in a fast, noninvasive, comprehensive, and inexpensive way--we are now on the edge of a new era of multimodality imaging that will probably change the paths and structure of medicine in many ways. Presently, hybrid imaging using SPECT/CT has been proven to increase sensitivity and specificity

  20. Incremental diagnostic benefit of resolution recovery software in patients with equivocal myocardial perfusion single-photon emission computed tomography (SPECT).

    PubMed

    Qutub, Mohammed A; Dowsley, Taylor; Ali, Iftikhar; Wells, R Glenn; Chen, Li; Ruddy, Terrence D; Chow, Benjamin J W

    2013-08-01

    Though myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is an established diagnostic method, equivocal studies are commonly encountered. New software has been introduced that incorporates resolution recovery (RR) and noise regulation into the reconstruction algorithm and has been used to facilitate "half-dose" and "half-time" studies. Its utility with "full-time, full-dose" acquisition has not been well studied. We sought to understand the potential benefit of incorporating RR software in equivocal SPECT studies. Patients with full-time, full-dose SPECT MPI were reviewed and those with equivocal results, who subsequently underwent cardiac Rb-82 positron emission tomography (PET) scan were identified. Image reconstruction was performed with iterative reconstruction (IR), attenuation correction (IR + AC), and RR software (IR + AC + RR). Images were anonymized and read blindly by consensus of two experienced readers. All images were qualitatively assessed and semi-quantitatively graded using summed stress and summed rest scores. 45 patients were included (28 males, age = 59.6 ± 9.9 years) and the diagnostic accuracy of each of the reconstruction algorithms (IR, IR + AC, IR + AC + RR) was compared to Rb-82 PET. Agreement of clinical diagnosis of each SPECT reconstruction with Rb-PET showed incremental improvement. The agreement with PET for IR + AC + RR (κ = 0.66, CI 0.454-0.875) is significantly better than for IR (κ = 0.22, CI 0.0-0.450, P = .005) and for IR + AC (κ = 0.32, CI 0.077-0.563, P = .03). Also, IR + AC + RR improved the clinical diagnosis in 14 cases and with overall improvement of reclassification proportion of 23.5% compared to IR (P = .01). Using PET as a reference standard, ROC curves were created for IR + AC + RR, IR + AC, and IR which showed incremental value of the area under the curve of IR + AC + RR (AUC: 0.87; CI 0.76-0.98) over IR + AC (AUC: 0.75; CI 0.61-0.89, P = .078), and over IR (AUC 0.68; CI 0

  1. Single photon emission computed tomography for the diagnosis of coronary artery disease: an evidence-based analysis.

    PubMed

    2010-01-01

    In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website).The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.htmlSINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY WITH CONTRAST FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based Analysis64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based AnalysisCARDIAC MAGNETIC RESONANCE IMAGING FOR

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2016-06-03

    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.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27257122

  5. Tetrofosmin early time gated post-stress single-photon emission computed tomography imaging: Feasibility and potential benefits

    PubMed Central

    Mérino, Bertrand; Blaire, Tanguy; Bailliez, Alban; Casset-Senon, Danielle; Levy, Maurice; Halley, Arnaud; Divry, Guillaume

    2010-01-01

    Background The purpose of this study is to evaluate the feasibility, the image quality, and the clinical relevance of an early gated post-stress (GPS) single-photon emission computed tomography (SPECT) tetrofosmin (Myoview™—GE Healthcare) acquisition protocol. Time delay between myocardial technetium-labeled tracer administration and SPECT acquisition is usually about 30 minutes after stress, and 45 to 60 minutes at rest: because of the absence of significant redistribution, perfusion images are related to stress even 30 minutes after stress injection, while function and thickening data obtained with gated acquisition 30 minutes after stress are mainly related to rest conditions. Methods 194 patients were prospectively included and analyzed, in a multicenter registry. Three gated-SPECT 99mTc-Tetrofosmin studies were performed per patient: GPS-SPECT, 30 minutes post-stress (GS30), and at rest (GR30). Results GPS image quality was excellent/good (93.9%), and similar to GS30 images (96.6%). The presence of adjacent myocardial sub-diaphragmatic activity on GPS images was similar to GS30 images (24% vs 22%), and less frequent than on GR30 images (31%). For perfusion, thickening, and motion scores, there was no significant difference between early and 30 minute post-stress in the global patient population, but significant differences were observed between GPS and GS30 for LVEF (65% ± 15% vs 63% ± 14%). In the ischemic patients, with the stress-rest protocol, the perfusion score was 14.2 on GPS images and 12.4 on GS30 images (P = .002). Conclusions Tetrofosmin early GPS-SPECT is feasible without impairment of image quality (better count rate). Ischemic defect size on early post-stress images is slightly more pronounced than at 30 minutes: this could modify therapeutic decision. This technique produces reliable function information during early post-stress period, and might be useful for disclosing transient motion abnormalities. PMID:21063927

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

    PubMed

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

    2015-02-01

    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) Is it safe to withdraw AC at 3 months if perfusion recovery is complete? Of 269 consecutive patients with suspected PE, 100 patients were diagnosed with PE using V/P SPECT. Sixty-seven patients with acute PE were followed up clinically and with V/P SPECT at 3 months. Sixty-four patients were subject to review and examination using V/P SPECT for a period of 6 months and 33 were followed up only clinically. Therapy was terminated after 3 months if perfusion was normalized, and patients were free of symptoms and the risk of hypercoagulability. Initial extension of PE did not have an impact on decision making. PE extension varied from 10 to 70% in the acute stage. After 3 months, complete resolution of PE was found in 48 patients. The treating pulmonologist decided to terminate therapy in 35 (73%) patients and to continue AC in 13 patients because of persistent risk factors. Six months later, at the second control stage, 53 patients had complete recovery of pulmonary perfusion. Eleven patients still had perfusion defects at 6 months. No recurrence was identified at 6 months in the 35 patients whose therapy was terminated after 3 months. No bleeding effects were observed in any of the patients during the 6-month follow-up. This study shows that AC therapy can be tailored, on an objective basis, by using V/P SPECT. Normalization of perfusion at 3 months of initial PE diagnosis was a reliable indicator that AC could be safely withdrawn in patients who were without hypercoagulability risk.

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

    PubMed

    Kung, M P; Hou, C; Oya, S; Mu, M; Acton, P D; Kung, H F

    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 [(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(i)=0.097 nM, using membrane preparations of LLC-PK(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(1) cells). Scatchard analysis of [(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(d) value of 0.25 nM+/-0.05 nM and a B(max) value of 272+/-30 fmol/ mg protein, while the PCA-lesioned membranes displayed a similar K(d), but with a reduced B(max) (20+/-7 fmol/ mg protein). Biodistribution of [(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 [(125)I]IDAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus, substantia nigra, interpeduncular nucleus, dorsal

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

    PubMed Central

    Begic, Amela; Opanković, Emina; Čukić, Vesna; Rustempašić, Medzida; Bašić, Amila; Miniati, Massimo; Jögi, Jonas

    2015-01-01

    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) Is it safe to withdraw AC at 3 months if perfusion recovery is complete? Patients and methods Of 269 consecutive patients with suspected PE, 100 patients were diagnosed with PE using V/P SPECT. Sixty-seven patients with acute PE were followed up clinically and with V/P SPECT at 3 months. Sixty-four patients were subject to review and examination using V/P SPECT for a period of 6 months and 33 were followed up only clinically. Therapy was terminated after 3 months if perfusion was normalized, and patients were free of symptoms and the risk of hypercoagulability. Initial extension of PE did not have an impact on decision making. Results PE extension varied from 10 to 70% in the acute stage. After 3 months, complete resolution of PE was found in 48 patients. The treating pulmonologist decided to terminate therapy in 35 (73%) patients and to continue AC in 13 patients because of persistent risk factors. Six months later, at the second control stage, 53 patients had complete recovery of pulmonary perfusion. Eleven patients still had perfusion defects at 6 months. No recurrence was identified at 6 months in the 35 patients whose therapy was terminated after 3 months. No bleeding effects were observed in any of the patients during the 6-month follow-up. Conclusion This study shows that AC therapy can be tailored, on an objective basis, by using V/P SPECT. Normalization of perfusion at 3 months of initial PE diagnosis was a reliable indicator that AC could be safely withdrawn in

  9. [A comparison of ventilation/perfusion single photon emission CT and CT pulmonary angiography for diagnosis of pulmonary embolism].

    PubMed

    Meng, Jing-jing; Zhang, Li-jun; Wang, Qian; Fang, Wei; Dai, Hao-jie; Yan, Jue; Wang, Tie; Yao, Zhi-ming; He, Jia; Li, Mei; Mi, Hong-zhi; Jiao, Jian; Zheng, Yu-min

    2013-03-01

    To assess the diagnostic accuracy of ventilation/perfusion (V/Q) single photon emission CT (SPECT) as compared to computed tomographic pulmonary angiography (CTPA) for pulmonary embolism (PE). In this prospective multicenter study, 111 patients in whom acute or sub-acute PE was clinically confirmed or suspected were enrolled. The patients underwent one-day method V/Q lung scan (including SPECT and planar imaging) within 3 days before and after completion of CTPA. The European Association of Nuclear Medicine (EANM) guidelines for ventilation/perfusion scintigraphy (2009) reference was used as the evaluation criteria of V/Q SPECT imaging. The refined modified prospective investigation of pulmonary embolism diagnosis (RM-PIOPED) criteria was used for evaluation of planar imaging. According to the direct and indirect signs of PE, the imaging of CTPA was evaluated. All patients were followed for at least 6 months. A diagnosis was finally made by consensus of respiratory physicians, radiologists and nuclear medicine physicians based on the clinical data, laboratory tests, imaging features and follow-up results. The difference among diagnostic methods was evaluated for significance using chi-square test. The receiver operator characteristic (ROC) curve was drawn according to the results of the 3 diagnostic tests. The area under ROC curve (AUC) was calculated and compared. P < 0.05 was considered statistically significant. Among the 111 patients, PE was confirmed in 80, and excluded in 31. The diagnostic sensitivity/specificity/accuracy of V/Q SPECT, planar imaging, and CTPA were 85.9%/93.5%/88.1%, 75.7%/92.9%/81.4%, and 85.5%/90.0%/86.8%, respectively. By ROC curve analysis, the AUC values of V/Q SPECT, planar imaging and CTPA were 0.898, 0.838, and 0.877, respectively; with 95% confidence intervals [CI] 0.831 to 0.966, 0.759 to 0.917, and 0.801 to 0.954, respectively. The area of the fitted smooth ROC curve was statistically significant (P < 0.05) as compared with the

  10. Early Dose Response to Yttrium-90 Microsphere Treatment of Metastatic Liver Cancer by a Patient-Specific Method Using Single Photon Emission Computed Tomography and Positron Emission Tomography

    SciTech Connect

    Campbell, Janice M. Wong, C. Oliver; Muzik, Otto; Marples, Brian; Joiner, Michael; Burmeister, Jay

    2009-05-01

    Purpose: To evaluate a patient-specific single photon emission computed tomography (SPECT)-based method of dose calculation for treatment planning of yttrium-90 ({sup 90}Y) microsphere selective internal radiotherapy (SIRT). Methods and Materials: Fourteen consecutive {sup 90}Y SIRTs for colorectal liver metastasis were retrospectively analyzed. Absorbed dose to tumor and normal liver tissue was calculated by partition methods with two different tumor/normal liver vascularity ratios: an average 3:1 and a patient-specific ratio derived from pretreatment technetium-99m macroaggregated albumin SPECT. Tumor response was quantitatively evaluated from fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography scans. Results: Positron emission tomography showed a significant decrease in total tumor standardized uptake value (average, 52%). There was a significant difference in the tumor absorbed dose between the average and specific methods (p = 0.009). Response vs. dose curves fit by linear and linear-quadratic modeling showed similar results. Linear fit r values increased for all tumor response parameters with the specific method (+0.20 for mean standardized uptake value). Conclusion: Tumor dose calculated with the patient-specific method was more predictive of response in liver-directed {sup 90}Y SIRT.

  11. Rest-redistribution 201-Thallium single photon emission computed tomography predicts myocardial infarction and cardiac death in patients with ischemic left ventricular dysfunction.

    PubMed

    Perrone-Filardi, Pasquale; Pace, Leonardo; Dellegrottaglie, Santo; Corrado, Luigi; Prastaro, Maria; Cafiero, Maria; Caiazzo, Gianluca; Marzano, Antonio; Cesarano, Paolo; Gargiulo, Paola; Paolillo, Stefania; Maglione, Antonio; Petretta, Andrea; Chiariello, Massimo

    2009-02-01

    The prognostic role of rest-redistribution 201-Thallium imaging has not been extensively investigated in patients with left ventricular ischemic dysfunction. The aim of this study was to evaluate the ability of rest-redistribution 201-Thallium single photon emission computed tomography to predict cardiac death and occurrence of acute myocardial infarction in patients with ischemic mild-to-moderate left ventricular dysfunction. One-hundred and twenty-six patients with chronic coronary artery disease and mean left ventricular ejection fraction 39 +/- 11% were followed-up for 30 +/- 17 months after a rest-redistribution 201-Thallium imaging single photon emission computed tomography. Cardiac death and acute myocardial infarction were considered as major cardiac events. During the follow up, 11 (9%) cardiac deaths and 9 (7%) acute myocardial infarctions occurred. The only variable showing significant difference between patients with and without events was the number of severe irreversible defects (1.7 +/- 1.9 versus 0.9 +/- 1.2, respectively; P = 0.02). By Kaplan-Meier analysis, the presence of three or less, or more than three severe defects was selected as the best cutoff to identify patients with longer event-free survival from cardiac death or acute myocardial infarction (log rank 19.84; P < 0.0001). When only cardiac death was considered as clinical event, the presence of at least two severe defects best separated patients who died from those who survived (log rank 8.68; P = 0.0032). Rest-redistribution 201-Thallium single photon emission computed tomography provides prognostic information in coronary patients with mild-to-moderate left ventricular dysfunction. The number of severe irreversible defects per patient is a powerful predictor of prognosis.

  12. Role of single photon emission computed tomography/computed tomography in diagnostic iodine-131 scintigraphy before initial radioiodine ablation in differentiated thyroid cancer

    PubMed Central

    Agrawal, Kanhaiyalal; Bhattacharya, Anish; Mittal, Bhagwant Rai

    2015-01-01

    Objectives: The study was performed to evaluate the incremental value of single photon emission computed tomography/computed tomography (SPECT/CT) over planar radioiodine imaging before radioiodine ablation in the staging, management and stratification of risk of recurrence (ROR) in differentiated thyroid cancer (DTC) patients. Materials and Methods: Totally, 83 patients (21 male, 62 female) aged 17–75 (mean 39.9) years with DTC were included consecutively in this prospective study. They underwent postthyroidectomy planar and SPECT/CT scans after oral administration of 37–114 MBq iodine-131 (I-131). The scans were interpreted as positive, negative or suspicious for tracer uptake in the thyroid bed, cervical lymph nodes and sites outside the neck. In each case, the findings on planar images were recorded first, without knowledge of SPECT/CT findings. Operative and pathological findings were used for postsurgical tumor–node–metastasis staging. The tumor staging was reassessed after each of these two scans. Results: Single photon emission computed tomography/computed tomography localized radioiodine uptake in the thyroid bed in 9/83 (10.8%) patients, neck nodes in 24/83 (28.9%) patients and distant metastases in 8/83 (9.6%) patients in addition to the planar study. Staging was changed in 8/83 (9.6%), ROR in 11/83 (13.2%) and management in 26/83 (31.3%) patients by the pretherapy SPECT/CT in comparison to planar imaging. SPECT/CT had incremental value in 32/83 patients (38.5%) over the planar scan. Conclusion: Single photon emission computed tomography/computed tomography is feasible during a diagnostic I-131 scan with a low amount of radiotracer. It improved the interpretation of pretherapy I-131 scintigraphy and changed the staging and subsequent patient management. PMID:26170564

  13. Arterial Spin Labeling Perfusion Magnetic Resonance Image with Dual Postlabeling Delay: A Correlative Study with Acetazolamide Loading (123)I-Iodoamphetamine Single-Photon Emission Computed Tomography.

    PubMed

    Haga, Sei; Morioka, Takato; Shimogawa, Takafumi; Akiyama, Tomoaki; Murao, Kei; Kanazawa, Yuka; Sayama, Tetsuro; Arakawa, Shuji

    2016-01-01

    Perfusion magnetic resonance image with arterial spin labeling (ASL) provides a completely noninvasive measurement of cerebral blood flow (CBF). However, arterial transient times can have a marked effect on the ASL signal. For example, a single postlabeling delay (PLD) of 1.5 seconds underestimates the slowly streaming collateral pathways that maintain the cerebrovascular reserve (CVR). To overcome this limitation, we developed a dual PLD method. A dual PLD method of 1.5  and 2.5 seconds was compared with (123)I-iodoamphetamine single-photon emission computed tomography with acetazolamide loading to assess CVR in 10 patients with steno-occlusive cerebrovascular disease. In 5 cases (Group A), dual PLD-ASL demonstrated low CBF with 1.5-second PLD in the target area, whereas CBF was improved with 2.5-second PLD. In the other 5 cases (Group B), dual PLD-ASL depicted low CBF with 1.5-second PLD, and no improvement in CBF with 2.5-second PLD in the target area was observed. On single-photon emission computed tomography, CVR was maintained in Group A but decreased in Group B. Although dual PLD methods may not be a completely alternative test for (123)I-iodoamphetamine single-photon emission computed tomography with acetazolamide loading, it is a feasible, simple, noninvasive, and repeatable technique for assessing CVR, even when employed in a routine clinical setting. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  14. Predicting the neural effect of switching from donepezil to galantamine based on single-photon emission computed tomography findings in patients with Alzheimer's disease.

    PubMed

    Oka, Mizuki; Nakaaki, Shutaro; Negi, Atsushi; Miyata, Jun; Nakagawa, Atsuo; Hirono, Nobutsugu; Mimura, Masaru

    2016-03-01

    A number of neuroimaging studies have addressed the specific effect of treatment with cholinesterase inhibitors on the frontal lobe in patients with Alzheimer's disease (AD). However, the neural effects of cholinesterase inhibitors on both apathy and executive dysfunction remain unclear. We examined whether baseline regional cerebral blood flow, as determined by using single-photon emission computed tomography, is capable of predicting changes in apathy and executive dysfunction in response to AD patients switching from donepezil to galantamine therapy. We conducted a 24-week, prospective, open-label study of AD patients treated with galantamine who did not respond to previous treatment with donepezil. Single-photon emission computed tomography was performed at baseline, and behaviour and cognitive assessments including the Mini-Mental State Examination, the Japanese version of the Alzheimer's Disease Assessment Scale-cognitive subscale, the Frontal Assessment Battery, the Neuropsychiatry Inventory Brief Questionnaire Form, and the Dysexecutive Questionnaire were conducted at three time points (baseline and after 12 and 24 weeks of galantamine therapy). After galantamine therapy, the Neuropsychiatry Inventory Brief Questionnaire Form scores (apathy, irritability, and aberrant motor symptoms) and the Dysexecutive Questionnaire score improved significantly. The single-photon emission computed tomography findings showed that lower baseline regional cerebral blood flow values in several frontal areas, including the dorsolateral and ventrolateral prefrontal cortex, the anterior cingulate, and the orbitofrontal cortex, predicted greater reductions in the score for apathy (distress) on the Neuropsychiatry Inventory Brief Questionnaire Form and the Dysexecutive Questionnaire score after patients switched from donepezil to galantamine therapy. Our study suggests that galantamine therapy, unlike donepezil, is characterized by a dual mechanism of action that may increase

  15. Single photon quantum cryptography.

    PubMed

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

    2002-10-28

    We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

  16. Usefulness of thallium-201 chloride single photon emission computed tomography for the preoperative diagnosis of fourth ventricle meningioma--case report.

    PubMed

    Ooigawa, Hidetoshi; Miyazawa, Takahito; Otani, Naoki; Fukui, Shinji; Nawashiro, Hiroshi; Shima, Katsuji

    2004-12-01

    A 51-year-old woman presented with a fourth ventricle meningioma manifesting as a 2-week history of dizziness and vomiting. Computed tomography (CT) and magnetic resonance (MR) imaging revealed a round mass lesion in the fourth ventricle. Thallium-201 chloride single photon emission computed tomography (201TlCl SPECT) showed high and rapid uptake on the early image and rapid washout on the delayed image. The preoperative diagnosis of meningioma could be established based on these findings. Total removal of the tumor was successfully performed. 201TlCl SPECT is useful for the preoperative diagnosis of fourth ventricle meningioma combined with CT, MR imaging, and angiography.

  17. Tc-99m Sulfur Colloid Lymphoscintigraphy with Single-photon Emission Computed Tomography/Computed Tomography in a Case of Acquired Vulval Lymphangiomas

    PubMed Central

    Tulsyan, Shruti; Tripathi, Madhavi; Das, Kalpa; Yadav, Divya; Shamim, Shamim Ahmed; Damle, Nishikant; Bal, Chandrasekhar

    2017-01-01

    We describe the lymphoscintigraphy findings of a 25-year-old female patient who was undergoing presurgical workup for lymphangiomas of the vulva. She had a history of treatment for disseminated tuberculosis 6 years back and presented with herpetiform oozing vesicles in the external genitalia. Single-photon emission computed tomography/computed tomography (SPECT/CT) confirmed cutaneous tracer accumulation in the vulval lesions and demonstrated the presence of densely calcified inguinal nodes secondary to healed tuberculosis as the etiology of secondary lymphangioma. PMID:28242996

  18. Importance of 123I-metaiodobenzylguanidine scintigraphy/single photon emission computed tomography for diagnosis and differential diagnostics of Parkinson syndromes.

    PubMed

    Jost, Wolfgang H; Del Tredici, Kelly; Landvogt, Christian; Braune, Stefan

    2010-01-01

    The goal of Parkinson syndrome diagnostics is twofold: early diagnosis on the one hand, and accurate differentiation among idiopathic and atypical Parkinson syndromes on the other. (123)I-metaiodobenzylguanidine scintigraphy is the only method that can distinguish with a high degree of sensitivity and specificity between atypical Parkinson syndromes and Parkinson's disease or dementia with Lewy bodies. Additional advantages are the method's widespread availability and radioactive exposure dose comparable to that for single photon emission computed tomography imaging with much lower costs. Only a single radiotracer study is necessary. (123)I-metaiodobenzylguanidine scintigraphy is an indispensable tool for purposes of differentiating among the various Parkinson syndromes.

  19. Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography.

    PubMed

    Damle, Nishikant A; Singhal, Abhinav; Mukherjee, Anirban; Sahoo, Manas Kumar; Tripathi, Madhavi; Bal, Chandrasekhar

    2013-04-01

    Hemimegalencephaly is a rare congenital neuronal migration disorder that can presents with the equally rare finding of hemihypoperfusion on brain perfusion single-photon emission computed tomography (SPECT). It is an extremely rare cause of intractable epilepsy. Technetium-99m ethyl cysteinate dimer (ECD) brain perfusion SPECT is useful in excluding other foci of hypoperfusion in the contralateral since hemispherectomy has been suggested to be the treatment of choice. Furthermore, hemimegalencephaly may present with hyper as well as hypoperfusion on ECD SPECT. We present the case of an 11-year-old male child with intractable seizures who showed hemihypoperfusion in the hemimegalecephalic hemisphere.

  20. Hemimegalencephaly: A rare cause of hemihypoperfusion on 99m technetium-ethyl cysteinate dimer brain perfusion single-photon emission computed tomography

    PubMed Central

    Damle, Nishikant A; Singhal, Abhinav; Mukherjee, Anirban; Sahoo, Manas Kumar; Tripathi, Madhavi; Bal, Chandrasekhar

    2013-01-01

    Hemimegalencephaly is a rare congenital neuronal migration disorder that can presents with the equally rare finding of hemihypoperfusion on brain perfusion single-photon emission computed tomography (SPECT). It is an extremely rare cause of intractable epilepsy. Technetium-99m ethyl cysteinate dimer (ECD) brain perfusion SPECT is useful in excluding other foci of hypoperfusion in the contralateral since hemispherectomy has been suggested to be the treatment of choice. Furthermore, hemimegalencephaly may present with hyper as well as hypoperfusion on ECD SPECT. We present the case of an 11-year-old male child with intractable seizures who showed hemihypoperfusion in the hemimegalecephalic hemisphere. PMID:24163513

  1. Neuroimaging of rapid eye movement sleep behavior disorder: transcranial ultrasound, single-photon emission computed tomography, and positron emission tomography scan data.

    PubMed

    Miyamoto, Masayuki; Miyamoto, Tomoyuki

    2013-08-01

    Idiopathic rapid eye movement sleep behavior disorder (iRBD), which typically develops in middle-aged individuals or later and progresses chronically, is a common clinical manifestation of Lewy body-related syndrome. It is important that combinations of neuroimaging markers in iRBD are considered for the purpose of diagnosing neurodegenerative diseases such as Parkinson disease (PD), dementia with Lewy body disease (DLB), or multiple system atrophy (MSA) at an early stage. Important advances have been made in the diagnosis of PD or DLB using imaging methods such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) scans or transcranial B-mode ultrasonography (TCS). These methods are important in clinical research, in which the identification of biomarkers for iRBD offers diagnostic opportunities and points the way to new therapeutic strategies. This review focuses on neuroimaging studies of rapid eye movement sleep behavior disorder (RBD) patients using techniques such as TCS, SPECT, and PET scans. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    SciTech Connect

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

    2015-01-26

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

  3. Single photon emission at 1.55 μm from charged and neutral exciton confined in a single quantum dash

    SciTech Connect

    Dusanowski, Ł. Syperek, M.; Mrowiński, P.; Rudno-Rudziński, W.; Misiewicz, J.; Sęk, G.; Somers, A.; Kamp, M.; Höfling, S.; Reithmaier, J. P.

    2014-07-14

    We investigate charged and neutral exciton complexes confined in a single self-assembled InAs/InGaAlAs/InP quantum dash emitting at 1.55 μm. The emission characteristics have been probed by measuring high-spatial-resolution polarization-resolved photoluminescence and cross-correlations of photon emission statistics at T = 5 K. The photon auto-correlation histogram of the emission from both the neutral and charged exciton indicates a clear antibunching dip with as-measured g{sup (2)}(0) values of 0.18 and 0.31, respectively. It proves that these exciton complexes confined in single quantum dashes of InP-based material system can act as true single photon emitters being compatible with standard long-distance fiber communication technology.

  4. Quantitative thallium-201 single photon emission computed tomography after oral dipyridamole for assessing the presence, anatomic location and severity of coronary artery disease

    SciTech Connect

    Borges-Neto, S.; Mahmarian, J.J.; Jain, A.; Roberts, R.; Verani, M.S.

    1988-05-01

    The objective of this investigation was to determine whether analysis of thallium-201 images as detected by quantitative single photon emission computed tomography after a single high oral dose of dipyridamole (300 mg) would accurately detect the presence of coronary artery disease and the anatomic location of the individual stenosis. Analyses were performed on 100 patients who concomitantly underwent diagnostic coronary arteriography and myocardial imaging. Tomographic myocardial perfusion defects were quantified using computer-generated polar maps. Eighty-four patients had significant coronary artery disease defined as greater than 50% luminal diameter stenosis. The sensitivity for detecting patients with coronary disease was 92% overall, 89% in patients without previous myocardial infarction and 97% in those with prior infarction. The technique had a sensitivity of 80, 87 and 51% for localizing coronary artery stenosis of the left anterior descending, the right coronary and the left circumflex artery, respectively. The corresponding specificity was 84, 92 and 92%. Furthermore, the presence of severe (greater than or equal to 70%) multivessel disease was identified with a sensitivity of 79% and a specificity of 87%. In conclusion, quantitative thallium-201 single photon emission computed tomography after oral dipyridamole has high sensitivity and specificity for diagnosing the presence of coronary disease, ascertaining the location of stenosed vessels and identifying the presence of multivessel disease.

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

    SciTech Connect

    Schmidt, Gordon Berger, Christoph; Veit, Peter; Metzner, Sebastian; Bertram, Frank; Bläsing, Jürgen; Dadgar, Armin; Strittmatter, André; Christen, Jürgen; Callsen, Gordon; Kalinowski, Stefan; Hoffmann, Axel

    2015-06-22

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

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

    SciTech Connect

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

    2014-08-18

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

  7. Single-photon emission at a rate of 143 MHz from a deterministic quantum-dot microlens triggered by a mode-locked vertical-external-cavity surface-emitting laser

    SciTech Connect

    Schlehahn, A.; Gschrey, M.; Schnauber, P.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T. Reitzenstein, S.; Gaafar, M.; Vaupel, M.; Stolz, W.; Rahimi-Iman, A.; Koch, M.

    2015-07-27

    We report on the realization of a quantum dot (QD) based single-photon source with a record-high single-photon emission rate. The quantum light source consists of an InGaAs QD which is deterministically integrated within a monolithic microlens with a distributed Bragg reflector as back-side mirror, which is triggered using the frequency-doubled emission of a mode-locked vertical-external-cavity surface-emitting laser (ML-VECSEL). The utilized compact and stable laser system allows us to excite the single-QD microlens at a wavelength of 508 nm with a pulse repetition rate close to 500 MHz at a pulse width of 4.2 ps. Probing the photon statistics of the emission from a single QD state at saturation, we demonstrate single-photon emission of the QD-microlens chip with g{sup (2)}(0) < 0.03 at a record-high single-photon flux of (143 ± 16) MHz collected by the first lens of the detection system. Our approach is fully compatible with resonant excitation schemes using wavelength tunable ML-VECSELs, which will optimize the quantum optical properties of the single-photon emission in terms of photon indistinguishability.

  8. Single-photon emission at a rate of 143 MHz from a deterministic quantum-dot microlens triggered by a mode-locked vertical-external-cavity surface-emitting laser

    NASA Astrophysics Data System (ADS)

    Schlehahn, A.; Gaafar, M.; Vaupel, M.; Gschrey, M.; Schnauber, P.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Stolz, W.; Rahimi-Iman, A.; Heindel, T.; Koch, M.; Reitzenstein, S.

    2015-07-01

    We report on the realization of a quantum dot (QD) based single-photon source with a record-high single-photon emission rate. The quantum light source consists of an InGaAs QD which is deterministically integrated within a monolithic microlens with a distributed Bragg reflector as back-side mirror, which is triggered using the frequency-doubled emission of a mode-locked vertical-external-cavity surface-emitting laser (ML-VECSEL). The utilized compact and stable laser system allows us to excite the single-QD microlens at a wavelength of 508 nm with a pulse repetition rate close to 500 MHz at a pulse width of 4.2 ps. Probing the photon statistics of the emission from a single QD state at saturation, we demonstrate single-photon emission of the QD-microlens chip with g(2)(0) < 0.03 at a record-high single-photon flux of (143 ± 16) MHz collected by the first lens of the detection system. Our approach is fully compatible with resonant excitation schemes using wavelength tunable ML-VECSELs, which will optimize the quantum optical properties of the single-photon emission in terms of photon indistinguishability.

  9. Differential diagnostic value of single-photon emission computed tomography/spiral computed tomography with Tc-99m-methylene diphosphonate in patients with spinal lesions.

    PubMed

    Zhang, Yiqiu; Shi, Hongcheng; Gu, Yushen; Xiu, Yan; Li, Beilei; Zhu, Weimin; Chen, Shuguang; Yu, Haojun

    2011-12-01

    The objective of this study was to compare the diagnostic value obtained using single-photon emission computed tomography (SPECT)/spiral computed tomography (CT) with Tc-99m methylene-diphosphonate with that obtained using SPECT alone in patients with spinal lesions. This was a retrospective study of 56 patients who underwent planar whole-body scintigraphy because of bone pain or osseous lesions that had been detected by other imaging techniques, or for the investigation of bone metastasis in patients with extraskeletal malignancies. Only patients who had hot spots detected in their spine and who had undergone single-photon emission computed tomography/computed tomography (SPECT/CT) imaging were included. One lesion from each patient was resected or biopsied for pathological diagnosis, and lesions for which a pathological diagnosis could be made were included in this study. Single-photon emission computed tomography (SPECT) and SPECT/CT images were independently interpreted by two experienced nuclear medicine physicians who had not been involved in the selection of data for the study. The physicians were aware of patients' sex, age, history of histologically confirmed extraskeletal malignancy, and whole-body scintigraphy results, but were unaware of the results of other investigations, such as X-ray, MRI, and laboratory tests. SPECT images were analyzed first, followed by SPECT/CT images. Each lesion was graded on a 4-point diagnostic scale (1, benign; 2, likely benign; 3, likely malignant; 4, malignant), and the inter-reviewer agreement and the agreement of the SPECT and SPECT/CT diagnoses with the pathology results were evaluated by κ scores. The pathology results revealed 39 malignant bone tumors and 17 benign lesions. In the malignant cases, 20 were bone metastases and 19 were malignant tumors of another histological type. The reviewers rated 67.9% of lesions as equivocal (grade 2-3) by SPECT, but only 19.6% as equivocal by SPECT/CT. The κ scores for inter

  10. Prevalence and predictors of ischemia and outcomes in outpatients with diabetes mellitus referred for single-photon emission computed tomography myocardial perfusion imaging.

    PubMed

    Bourque, Jamieson M; Patel, Chetan A; Ali, Mohamed M; Perez, Margarita; Watson, Denny D; Beller, George A

    2013-05-01

    Background- The prevalence of ischemia and its prediction of events are unclear in outpatients with diabetes mellitus in the modern era of intensive medical management. We sought to identify the prevalence of ischemia, subsequent cardiac events, and impact of sex, stress type, and symptom status on these findings in a cohort of stable outpatients with diabetes mellitus referred for single-photon emission computed tomography myocardial perfusion imaging (MPI). Methods and Results- The study cohort included 575 consecutive outpatients with diabetes mellitus who underwent quantitative, gated single-photon emission computed tomography MPI. Clinical information, stress MPI variables, and cardiac events were prospectively collected and analyzed. The study population was at intermediate risk of coronary artery disease or had known coronary artery disease (40.3%); 29% of patients were asymptomatic at the time of stress testing. Scintigraphic ischemia and significant (≥10%) left ventricular ischemia were present in 126 patients (21.9%) and 29 patients (5.0%), respectively, and <1% of patients had early revascularization. The risk of ischemia was increased >2-fold by male sex (P<0.001), but was not impacted by pharmacological stress (P=0.15) or presence of symptoms (P=0.89). During a median 4.4 years follow-up, the rate of cardiac death/nonfatal myocardial infarction was moderate at 2.6%/y (cardiac death 0.8%/y) in the total cohort, but was 5.7%/y in those with ischemia (P<0.001). Pharmacological stress predicted a higher cardiac event rate (P<0.001) but symptoms did not (P=0.55). Conclusions- This cohort of stable outpatients with diabetes mellitus referred for single-photon emission computed tomography had low rates of significant ischemia and early revascularization; an initially low cardiac event rate increased after 2 years. Independent predictors of cardiac death/nonfatal myocardial infarction were known coronary artery disease, pharmacological stress, and MPI

  11. Method for reducing background artifacts from images in single-photon emission computed tomography with a uniformly redundant array coded aperture

    NASA Astrophysics Data System (ADS)

    Vassilieva, Olga I.; Chaney, Roy C.

    2002-03-01

    Uniformly redundant array coded apertures have proven to be useful in the design of collimators for x-ray astronomy. They were initially expected to be equally successful in single-photon emission computed tomography (SPECT). Unfortunately, the SPECT images produced by this collimator contain artifacts, which mask the true picture and can lead to false diagnosis. Monte Carlo simulation has shown that the formation of a composite image will significantly reduce these artifacts. A simulation of a tumor in a compressed breast phantom has produced a composite image, which clearly indicates the presence of a 5 mm x 5 mm x 5 mm tumor with a 6:1 intensity ratio relative to the background tissue.

  12. Comparison of single-photon emission computed tomography with (123I)iodoamphetamine and xenon-enhanced computed tomography for assessing regional cerebral blood flow

    SciTech Connect

    Hellman, R.S.; Collier, B.D.; Tikofsky, R.S.; Kilgore, D.P.; Daniels, D.L.; Haughton, V.M.; Walsh, P.R.; Cusick, J.F.; Saxena, V.K.; Palmer, D.W.

    1986-12-01

    Regional CBF (rCBF) images obtained from xenon-enhanced computed tomography (XeCT) and single-photon emission computed tomography (SPECT) with N-isopropyl-p-(/sup 123/I)iodoamphetamine (IMP) done with a rotating gamma-camera were compared in nine patients. Both XeCT and SPECT/IMP demonstrated flow abnormalities at all sites of infarction identified by CT, while detecting reduced rCBF in areas normal by CT in eight of the nine patients. All areas that were abnormal on XeCT were abnormal on the comparable SPECT/IMP images. The major advantages of XeCT are its greater resolution and potential for noninvasive quantitation of rCBF, while the major advantage of SPECT/IMP is its visualization of the entire brain on transverse, coronal, and sagittal sections.

  13. [Detection of cerebral hypoperfusion using single photon emission computed tomography image analysis and statistical parametric mapping in patients with Parkinson's disease or progressive supranuclear palsy].

    PubMed

    Harada, Kengo; Saeki, Hiroshi; Matsuya, Eiji; Okita, Izumi

    2013-11-01

    We carried out differential diagnosis of brain blood flow images using single-photon emission computed tomography (SPECT) for patients with Parkinson's disease (PD) or progressive supranuclear paralysis (PSP) using statistical parametric mapping (SPM) and to whom we had applied anatomical standardization. We studied two groups and compared brain blood flow images using SPECT (N-isopropyl-4-iodoamphetamine [(123)I] hydrochloride injection, 222 MGq dosage i.v.). A total of 27 patients were studied using SPM: 18 with PD and 9 with PSP; humming bird sign on MRI was from moderate to medium. The decline of brain bloodstream in the PSP group was more notable in the midbrain, near the domain where the humming bird sign was observable, than in the PD group. The observable differences in brain bloodstream decline in the midbrain of PSP and PD patients suggest the potential usefulness of this technique's clinical application to distinction diagnosis.

  14. Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Asokumar, Premkumar; Malaikkal, Anjali; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2015-01-01

    Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region.

  15. Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Asokumar, Premkumar; Malaikkal, Anjali; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2015-01-01

    Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region. PMID:26097427

  16. Thallium-201 single photon emission tomography after injecting an antimuscarinic agent compared with computed tomography for the diagnosis of recurrent colorectal cancer. Report of three cases.

    PubMed

    Fallahi, Babak; Beiki, Davood; Assadi, Majid; Esfahani, Armaghan Fard

    2006-01-01

    Thallium-201 chloride ((201)TlCl) is frequently used for imaging of a variety of malignant tumors viz., thyroid, lung, brain, bone and breast, however in patients with colorectal cancer, its role is not well established. In this case report we present three patients with colorectal cancer recurrence, with inconclusive computed tomography (CT) findings while (201)TlCl single photon emission tomography (SPET) after injecting an anti-muscarinic agent, showed findings corroborating with the final diagnosis. Correlating CT with (201)TlCl-SPET findings, recurrence of the colorectal cancer was diagnosed in two cases; surgical treatment accordingly planned, confirmed the diagnosis. In the third case, CT was falsely positive while (201)TlCl-SPET was negative, compatible with the final diagnosis.

  17. Perirolandic hypoperfusion on single-photon emission computed tomography in term infants with perinatal asphyxia: comparison with MRI and clinical findings.

    PubMed

    Yoon, C S; Ryu, Y H; Kim, D I; Park, C I; Lee, S; Yoon, P H; Jeon, T J; Lee, J D

    2000-12-01

    We describe the findings on single-photon emission computed tomography (SPECT) in patients with perinatal asphyxia at term, with perirolandic cortico-subcortical changes on MRI, and to correlate them with clinical features. SPECT of 7 patients was obtained after injection of 185-370 MBq of Tc-99m-ECD (ethyl cysteinate dimer). The patients had spastic quadriplegia (7/7) with perinatal asphyxia (6/7) at term (7/7). The results were correlated with the MRI findings. Hypoperfusion of the perirolandic cortex was clearly seen on SPECT in all patients, even in two with subtle changes on MRI. SPECT demonstrated a more extensive area of involvement than MRI, notably in the cerebellum (in 4), the thalamus (in 7) and basal ganglia (in 5), where MRI failed to show any abnormalities.

  18. Regional cerebral blood flow assessed by single photon emission computed tomography (SPECT) in dogs with congenital portosystemic shunt and hepatic encephalopathy.

    PubMed

    Or, Matan; Peremans, Kathelijne; Martlé, Valentine; Vandermeulen, Eva; Bosmans, Tim; Devriendt, Nausikaa; de Rooster, Hilde

    2017-02-01

    Regional cerebral blood flow (rCBF) in eight dogs with congenital portosystemic shunt (PSS) and hepatic encephalopathy (HE) was compared with rCBF in eight healthy control dogs using single photon emission computed tomography (SPECT) with a (99m)technetium-hexamethylpropylene amine oxime ((99m)Tc-HMPAO) tracer. SPECT scans were abnormal in all PSS dogs. Compared to the control group, rCBF in PSS dogs was significantly decreased in the temporal lobes and increased in the subcortical (thalamic and striatal) area. Brain perfusion imaging alterations observed in the dogs with PSS and HE are similar to those in human patients with HE. These findings suggest that dogs with HE and PSS have altered perfusion of mainly the subcortical and the temporal regions of the brain.

  19. Single-photon sources

    NASA Astrophysics Data System (ADS)

    Lounis, Brahim; Orrit, Michel

    2005-05-01

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

  20. Assessment of coronary ischaemia by myocardial perfusion dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography, and coronary angiography in children with Kawasaki disease: pre- and post-coronary bypass grafting.

    PubMed

    Mostafa, Mostafa S; Sayed, Ashraf O; Al Said, Yasser M

    2015-06-01

    Coronary artery lesions in Kawasaki disease invasively assessed by coronary angiography. Evaluation of myocardial perfusion by single-photon emission computed tomography may identify the haemodynamic significance of coronary lesions. To evaluate diagnostic accuracy of dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography as a possible alternative to invasive coronary angiography for detection and follow-up of myocardial ischaemia in patients with Kawasaki disease, and pre- and post-coronary bypass grafting. Coronary angiography and single-photon emission computed tomography were performed on 21 patients who were classified into three groups - group I (stenosis), group II (giant aneurysms), and group III (small aneurysms). Of the 21 patients, 16 (groups I and II) patients with myocardial perfusion defects, who underwent coronary bypass grafting, were followed up with single-photon emission computed tomography. In group I, all patients had significant coronary stenosis and 100% of them had perfusion defects in the anterior and septal walls. In group II, all patients had giant aneurysms and 83% of them had inferior and inferolateral perfusion defects. In group III, all patients had small aneurysms and 100% of them had normal perfusion. Pre-coronary bypass grafting myocardial ischaemic defects disappeared in all patients after surgery. Sensitivity, specificity, and accuracy of single-photon emission computed tomography were 94, 100, and 95%, respectively. Technetium-99 m tetrofosmin single-photon emission computed tomography can be applied as an accurate non-invasive diagnostic technique for detecting myocardial perfusion defects with coronary artery lesions, and to show improved or even normalised perfusion of the myocardium in patients after surgical revascularisation.

  1. Prognostic Implications of Discordant Results of Myocardial Perfusion Single-Photon Emission Computed Tomography and Exercise ECG Test in Patients with Stable Angina.

    PubMed

    Kowalczyk, Ewelina; Filipiak-Strzecka, Dominika; Hamala, Piotr; Śmiech, Nina; Kasprzak, Jarosław D; Kuśmierek, Jacek; Płachcińska, Anna; Lipiec, Piotr

    2015-01-01

    ECG exercise treadmill test (ExT) and myocardial perfusion SPECT (single photon emission computed tomography) study are widely used for the non-invasive evaluation of patients with coronary artery disease (CAD). To assess long-term prognosis in patients with suspected or known coronary artery disease (CAD), in whom ECG exercise treadmill test (ExT) and myocardial perfusion single photon emission computed tomography (SPECT) provided discordant results are lacking. Four hundred eighty three patients with suspected or known stable CAD underwent 99mTc-methoxyisobutylisonitrile SPECT and ExT. SPECT was considered positive (+) if inducible or mixed perfusion defects were detected. ExT was evaluated using widely accepted criteria. Based on the results of both examinations the patients were divided into 4 subgroups: group 1 - SPECT (+) and ExT (+), group 2 - SPECT (+) and ExT (-), group 3 - SPECT (-) and ExT (+), group 4 - SPECT (-) and ExT (-). After a mean follow-up of 59 ± 7 months, major cardiac events (cardiac death and nonfatal myocardial infarction combined) and revascularizations were more prevalent in groups 1 and 2 than in groups 3 and 4. However, the statistical significance (p ≤ 0.01) was reached only for the following differences: in major cardiac events - group 1 vs group 3 and group 1 vs group 4; in revascularizations - group 1 vs. group 3, group 1 vs. group 4 and group 2 vs group 4 and in cardiac hospitalizations - group 1 vs. group 4 and group 2 vs. group 4. Positive myocardial perfusion SPECT result is associated with similar clinical outcome irrespectively of ExT result in long-term follow-up.

  2. Variable uptake feature of focal nodular hyperplasia in Tc-99m phytate hepatic scintigraphy/single-photon emission computed tomography-A parametric analysis.

    PubMed

    Hsu, Yu-Ling; Chen, Yu-Wen; Lin, Chia-Yang; Lai, Yun-Chang; Chen, Shinn-Cherng; Lin, Zu-Yau

    2015-12-01

    Tc-99m phytate hepatic scintigraphy remains the standard method for evaluating the functional features of Kupffer cells. In this study, we demonstrate the variable uptake feature of focal nodular hyperplasia (FNH) in Tc-99m phytate scintigraphy. We reviewed all patients who underwent Tc-99m phytate hepatic scintigraphy between 2008 and 2012 in Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Cases with FNH were diagnosed on the basis of pathology or at least one or more prior imaging with a periodic clinical follow-up. All patients received a standard protocol of dynamic flow study and planar and Tc-99m phytate single-photon emission computed tomography (E. CAM; Siemens). The correlation of variable nodular radioactivity with parameters such as tumor size and localization was analyzed. In total, 15 lesions of 14 patients in the clinic were diagnosed as FNH. The tumor size was approximately 2.9-7.4 cm (mean size 4.6 cm). Four lesions were larger than 5 cm. The major anatomic distribution was in the right hepatic lobe (10 lesions), particularly in the superior segments (7 lesions). Tc-99m phytate single-photon emission computed tomography imaging for determining the functional features of Kupffer cells included cool/cold (8 lesions), isoradioactive/warm (6 lesions), and hot (1 lesion) patterns of uptake. We did not observe any statistically significant correlation between variable nodular radioactivity and tumor size (p=0.68) or localization (p=0.04). Herein, we demonstrate the variable uptake feature of FNH in Tc-99m phytate scintigraphy. In small FNH tumors (< 5 cm), increased or equal uptake still provided specificity for the differential diagnosis of hepatic solid tumors.

  3. Comparison of sulfur hexafluoride microbubble (SonoVue)-enhanced myocardial contrast echocardiography with gated single-photon emission computed tomography for detection of significant coronary artery disease: a large European multicenter study.

    PubMed

    Senior, Roxy; Moreo, Antonella; Gaibazzi, Nicola; Agati, Luciano; Tiemann, Klaus; Shivalkar, Bharati; von Bardeleben, Stephan; Galiuto, Leonarda; Lardoux, Hervé; Trocino, Giuseppe; Carrió, Ignasi; Le Guludec, Dominique; Sambuceti, Gianmario; Becher, Harald; Colonna, Paolo; Ten Cate, Folkert; Bramucci, Ezio; Cohen, Ariel; Bezante, Gianpaolo; Aggeli, Costantina; Kasprzak, Jaroslaw D

    2013-10-08

    echocardiography [MCE] to single photon emission computerized tomography [ECG-GATED SPECT], at rest and at peak of low-dose Dipyridamole stress test, in the assessment of significant coronary artery disease [CAD] in patients with suspect or known CAD using Coronary Angiography as Gold Standard-SonoVue MCE vs SPECT; EUCTR2007-003492-39-GR). Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Phase II safety and clinical comparison with single-photon emission computed tomography myocardial perfusion imaging for detection of coronary artery disease: flurpiridaz F 18 positron emission tomography.

    PubMed

    Berman, Daniel S; Maddahi, Jamshid; Tamarappoo, B K; Czernin, Johannes; Taillefer, Raymond; Udelson, James E; Gibson, C Michael; Devine, Marybeth; Lazewatsky, Joel; Bhat, Gajanan; Washburn, Dana

    2013-01-29

    This was a phase II trial to assess flurpiridaz F 18 for safety and compare its diagnostic performance for positron emission tomography (PET) myocardial perfusion imaging (MPI) with Tc-99m single-photon emission computed tomography (SPECT) MPI with regard to image quality, interpretative certainty, defect magnitude, and detection of coronary artery disease (CAD) (≥50% stenosis) on invasive coronary angiography (ICA). In pre-clinical and phase I studies, flurpiridaz F 18 has shown characteristics of an essentially ideal MPI tracer. One hundred forty-three patients from 21 centers underwent rest-stress PET and Tc-99m SPECT MPI. Eighty-six patients underwent ICA, and 39 had low-likelihood of CAD. Images were scored by 3 independent, blinded readers. A higher percentage of images were rated as excellent/good on PET versus SPECT on stress (99.2% vs. 88.5%, p < 0.01) and rest (96.9% vs. 66.4, p < 0.01) images. Diagnostic certainty of interpretation (percentage of cases with definitely abnormal/normal interpretation) was higher for PET versus SPECT (90.8% vs. 70.9%, p < 0.01). In 86 patients who underwent ICA, sensitivity of PET was higher than SPECT (78.8% vs. 61.5%, respectively, p = 0.02). Specificity was not significantly different (PET: 76.5% vs. SPECT: 73.5%). Receiver-operating characteristic curve area was 0.82 ± 0.05 for PET and 0.70 ± 0.06 for SPECT (p = 0.04). Normalcy rate was 89.7% with PET and 97.4% with SPECT (p = NS). In patients with CAD on ICA, the magnitude of reversible defects was greater with PET than SPECT (p = 0.008). Extensive safety assessment revealed that flurpiridaz F 18 was safe in this cohort. In this phase 2 trial, PET MPI with flurpiridaz F 18 was safe and superior to SPECT MPI for image quality, interpretative certainty, and overall CAD diagnosis. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  5. Lifetime Reduction and Enhanced Emission of Single Photon Color Centers in Nanodiamond via Surrounding Refractive Index Modification

    PubMed Central

    Khalid, Asma; Chung, Kelvin; Rajasekharan, Ranjith; Lau, Desmond W.M.; Karle, Timothy J.; Gibson, Brant C.; Tomljenovic-Hanic, Snjezana

    2015-01-01

    The negatively-charged nitrogen vacancy (NV−) center in diamond is of great interest for quantum information processing and quantum key distribution applications due to its highly desirable long coherence times at room temperature. One of the challenges for their use in these applications involves the requirement to further optimize the lifetime and emission properties of the centers. Our results demonstrate the reduction of the lifetime of NV− centers, and hence an increase in the emission rate, achieved by modifying the refractive index of the environment surrounding the nanodiamond (ND). By coating the NDs in a polymer film, experimental results and numerical calculations show an average of 63% reduction in the lifetime and an average enhancement in the emission rate by a factor of 1.6. This strategy is also applicable for emitters other than diamond color centers where the particle refractive index is greater than the refractive index of the surrounding media. PMID:26109500

  6. Comparison of N-isopropyl (/sup 123/I) p-iodoamphetamine brain scans using Anger camera scintigraphy and single-photon emission tomography

    SciTech Connect

    Lee, R.G.; Hill, T.C.; Holman, B.L.; Uren, R.; Clouse, M.E.

    1982-12-01

    N-isopropyl (/sup 123/I) p-iodoamphetamine (IMP), which is extracted by the brain in proportion to regional blood flow, has been shown to be useful with single-photon emission tomography (SPECT) in the assessment of pathologic states related to blood flow. Because emission tomographic equipment is not yet available at most hospitals, the authors compared IMP brain images obtained with an Anger camera with those obtained by SPECT to determine the usefulness of IMP scintigraphy. Thirty-nine pairs of studies were performed on 12 control patients, 14 patients with stroke, three patients with tumors, and a miscellaneous group of eight patients. Planar scintigraphy showed good correlation with SPECT in determining the presence or absence of abnormality in all patients except one with a very small brain stem infarction that was not detected by planar imaging. Anger images showed poor contrast resolution compared with SPECT images. It is thus expected that SPECT will result in better lesion detection when smaller lesions are studied. Planar scintigraphy is not capable of providing quantitative measurement of regional cerebral blood flow.

  7. Comparison of N-isopropyl (I-123) p-iodoamphetamine brain scans using Anger camera scintigraphy and single-photon emission tomography

    SciTech Connect

    Lee, R.G.; Hill, T.C.; Holman, B.L.; Uren, R.; Clouse, M.E.

    1982-12-01

    N-isopropyl (I-123) p-iodoamphetamine (IMP), which is extracted by the brain in proportion to regional blood flow, has been shown to be useful with single-photon emission tomography (SPECT) in the assessment of pathologic states related to blood flow. Because emission tomographic equipment is not yet available at most hospitals, the authors compared IMP brain images obtained with an Anger camera with those obtained by SPECT to determine the usefulness of IMP scintigraphy. Thirty-nine pairs of studies were performed on 12 control patients, 14 patients with stroke, three patients with tumors, and a miscellaneous group of eight patients. Planar scintigraphy showed good correlation with SPECT in determining the presence or absence of abnormality in all patients except one with a very small brain stem infarction that was not detected by planar imaging. Anger images showed poor contrast resolution compared with SPECT images. It is thus expected that SPECT will result in better lesion detection when smaller lesions are studied. Planar scintigraphy is not capable of providing quantitative measurement of regional cerebral blood flow.

  8. Exercise four hour redistribution thallium-201 single photon emission computed tomography and exercise induced ST segment elevation in detecting the viable myocardium in patients with acute myocardial infarction

    PubMed Central

    Yamagishi, H; Akioka, K; Takagi, M; Tanaka, A; Takeuchi, K; Yoshikawa, J; Ochi, H

    1999-01-01

    Objective—To investigate the specificity and sensitivity of the combination of redistribution in exercise thallium-201 single photon emission computed tomography (SPECT) and exercise induced ST elevation for detecting the viable myocardium in patients with acute myocardial infarction.
Design—37 patients were studied within seven weeks of onset of Q wave myocardial infarction (anterior in 22, inferior in 15). All patients underwent exercise four hour redistribution thallium-201 SPECT and positron emission tomography using fluorine-18-fluorodeoxyglucose (FDG) and nitrogen-13 ammonia under fasting conditions.
Results—Sixteen patients showed exercise induced ST elevation ⩾ 1.5 mm, and 15 of these had increased FDG uptake in the infarct region. Eleven of 16 patients (10 of 11 patients with anterior infarctions) with irreversible thallium-201 defects and increased FDG uptake showed exercise induced ST elevation. The sensitivity, specificity, and predictive accuracy of redistribution, exercise induced ST segment elevation, or both for detecting increased FDG uptake were 82%, 75%, and 67% (94%, 75%, and 91% for anterior infarctions), respectively. 
Conclusions—In patients with acute Q wave myocardial infarction, the combination of redistribution in exercise thallium-201 SPECT and exercise induced ST elevation can detect the viable myocardium in the infarct region with high sensitivity and specificity, especially in patients with anterior infarctions.

 Keywords: acute myocardial infarction;  viability;  exercise induced ST elevation;  exercise thallium-201 SPECT PMID:10220539

  9. Five-element Johann-type x-ray emission spectrometer with a single-photon-counting pixel detector

    SciTech Connect

    Kleymenov, Evgeny; Bokhoven, Jeroen A. van; David, Christian; Janousch, Markus; Studer, Marco; Willimann, Markus; Bergamaschi, Anna; Henrich, Beat; Nachtegaal, Maarten; Glatzel, Pieter; Alonso-Mori, Roberto

    2011-06-15

    A Johann-type spectrometer with five spherically bent crystals and a pixel detector was constructed for a range of hard x-ray photon-in photon-out synchrotron techniques, covering a Bragg-angle range of 60 deg. - 88 deg. The spectrometer provides a sub emission line width energy resolution from sub-eV to a few eV and precise energy calibration, better than 1.5 eV for the full range of Bragg angles. The use of a pixel detector allows fast and easy optimization of the signal-to-background ratio. A concentration detection limit below 0.4 wt% was reached at the Cu K{alpha}{sub 1} line. The spectrometer is designed as a modular mobile device for easy integration in a multi-purpose hard x-ray synchrotron beamline, such as the SuperXAS beamline at the Swiss Light Source.

  10. Five-element Johann-type x-ray emission spectrometer with a single-photon-counting pixel detector.

    PubMed

    Kleymenov, Evgeny; van Bokhoven, Jeroen A; David, Christian; Glatzel, Pieter; Janousch, Markus; Alonso-Mori, Roberto; Studer, Marco; Willimann, Markus; Bergamaschi, Anna; Henrich, Beat; Nachtegaal, Maarten

    2011-06-01

    A Johann-type spectrometer with five spherically bent crystals and a pixel detector was constructed for a range of hard x-ray photon-in photon-out synchrotron techniques, covering a Bragg-angle range of 60°-88°. The spectrometer provides a sub emission line width energy resolution from sub-eV to a few eV and precise energy calibration, better than 1.5 eV for the full range of Bragg angles. The use of a pixel detector allows fast and easy optimization of the signal-to-background ratio. A concentration detection limit below 0.4 wt% was reached at the Cu Kα(1) line. The spectrometer is designed as a modular mobile device for easy integration in a multi-purpose hard x-ray synchrotron beamline, such as the SuperXAS beamline at the Swiss Light Source.

  11. Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer's disease and depression.

    PubMed

    Kirino, Eiji

    2017-06-22

    To evaluate usefulness of single photon emission computed tomography (SPECT) with three-dimensional stereotactic surface projection (3D-SSP) in distinguishing between Alzheimer's disease (AD) and depression. We studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following: (1) the Minimal Mental State Examination; (2) the Hamilton Rating Scale for Depression; (3) Clinical Global Impression-Severity scale (CGI-S); and (4) SPECT imaging with 3D-SSP. The MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency. We investigated whether these patients could be categorized as types: Type A (true AD), Type B (pseudo-dementia), Type C (occult AD), and Type D (true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.

  12. Cerebral blood flow measurement in patients with impaired consciousness: usefulness of 99mTc-HMPAO single-photon emission tomography in clinical practice.

    PubMed

    Chang, C C; Kuwana, N; Noji, M; Tanabe, Y; Koike, Y; Ikegami, T

    1998-09-01

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

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

    SciTech Connect

    Yamamoto, S.; Matsushima, H.; Suzuki, A.; Sotobata, I.; Indo, T.; Matsuoka, Y.

    1988-04-01

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

  14. Validation of left ventricular function from gated single photon computed emission tomography by using a scintillator-photodiode camera: a dynamic myocardial phantom study.

    PubMed

    Kubo, N; Mabuchi, M; Katoh, C; Arai, H; Morita, K; Tsukamoto, E; Morita, Y; Tamaki, N

    2002-07-01

    A scintillator-photodiode camera is able to acquire single photon emission computed tomography (SPECT) images by using a rotating chair system. We validated the left ventricular (LV) parameters of this camera system utilizing a dynamic myocardial phantom. Gated myocardial SPECT of a dynamic myocardial phantom (Hokkaido University type; end diastolic volume (EDV), 143 ml; end systolic volume (ESV), 107 ml; ejection fraction (EF), 25%) was performed with this scintillation camera. LV parameters were calculated using pre-installed software (Mirage Myocardial Perfusion SPECT) (study 1) and the other software (QGS; Cedars-Sinai) (study 2). For comparison, SPECT from a traditional Anger camera were processed by the QGS software (study 3). The estimated volumes were similar among the three studies (EDV, 110+/-8 ml in study 1, 112+/-2 ml in study 2 and 111+/-1 ml in study 3; ESV, 86+/-8 ml in study 1, 93+/-4 ml in study 2 and 91+/-2 ml in study 3). The estimated EFs were 23+/-3%, 17+/-2%, and 18+/-1%, respectively. The calculated volume within each study was underestimated by approximately the same degree. However, each estimated EF value for each study was close to the actual value. The estimated LV function using the scintillator-photodiode camera system may be considered as a suitable alternative to the traditional Anger camera system.

  15. Quantitative severity of stress thallium-201 myocardial perfusion single-photon emission computed tomography defects in one-vessel coronary artery disease.

    PubMed

    Matzer, L; Kiat, H; Van Train, K; Germano, G; Papanicolaou, M; Silagan, G; Eigler, N; Maddahi, J; Berman, D S

    1993-08-01

    The relation between the quantitative myocardial perfusion defect severity of exercise thallium-201 single-photon emission computed tomography (SPECT) and the quantitative degree of coronary stenosis was examined in 18 patients with 1-vessel disease (> or = 50% diameter stenosis), and abnormal thallium-201 SPECT. A total of 26 vessels were analyzed. Thallium-201 SPECT quantitative defect severity score was derived by summing the number of pixels in a coronary territory in which counts fell below the normal mean and multiplied by the number of SDs by which they fell below the normal mean. The thallium-201 defect severity score was significantly (p < 0.001) related to the maximal percent luminal diameter narrowing (r = 0.93), percent area narrowing (r = 0.89), absolute stenotic area (r = 0.79), and absolute stenotic diameter (r = 0.81). As expected, the strongest relation between thallium-201 defect severity and quantitative angiographic indexes was in the low and high ranges of coronary stenosis, with more variability and lower correlation coefficients (percent diameter: r = 0.75, p < 0.02, percent area stenosis: r = 0.63, p < 0.05) in the middle ranges (50 to 80% diameter stenosis). This observation is likely to be due to the complex flow characteristics across stenotic lesions. The findings suggest that in a select population, thallium-201 defect severity is potentially useful for noninvasive characterization of the functional severity of coronary artery stenosis and may complement coronary angiography in predicting functionally significant stenosis.

  16. Infarct size measured by single photon emission computed tomographic imaging with (99m)Tc-sestamibi: A measure of the efficacy of therapy in acute myocardial infarction.

    PubMed

    Gibbons, R J; Miller, T D; Christian, T F

    Use of mortality as an end point in randomized trials of reperfusion therapy requires increasingly large sample sizes to test advances compared with existing therapy, which is already highly effective. There has been a growing interest in infarct size measurements by (99m)Tc-sestamibi SPECT (single photon emission computed tomographic) imaging as a surrogate end point. We reviewed the reports published in English regarding infarct size measurements by (99m)Tc-sestamibi. Four separate lines of published evidence support the validity of SPECT imaging with (99m)Tc-sestamibi for determination of infarct size. This end point has been used in a total of 7 randomized trials-1 single center and 6 multicenter. The end point compares favorably with left ventricular function and infarct size measurements with the use of other radiopharmaceuticals. The most important limitation of this approach is the absence thus far of a randomized trial that has shown a corresponding decrease in mortality in association with a therapy that reduces infarct size. SPECT imaging with (99m)Tc-sestamibi is the best available measurement tool for infarct size. It has already served as an end point in early pilot studies to evaluate potential efficacy and in dose-ranging studies. It has the potential to serve as a surrogate end point to uncover advantages of new therapies that may be equivalent to existing therapies with respect to early mortality.

  17. Bone mineral density and single photon emission computed tomography changes after total knee arthroplasty: a 2-year follow-up study.

    PubMed

    Soininvaara, Tarja; Nikola, Tua; Vanninen, Esko; Miettinen, Hannu; Kröger, Heikki

    2008-03-01

    Dual X-ray absorptionmetry (DXA) provides a highly reproducible method for quantitative analysis and monitoring periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). Single photon emission computed tomography (SPECT) with bone avid radiopharmaceuticals reflects bone metabolic activity and circulation. We combined information from DXA and SPECT to assess the evaluation of the dynamic balance between BMD and bone turnover. Sixteen patients underwent serial DXA (Lunar Expert XL) and 99mTc-methylene diphosphonate SPECT measurements until 2 years after TKA. A rapid bone loss, up to 25.5%, was detected in femur during the first six postoperative months. However, tibial periprosthetic BMD remained close to baseline. There was a significant correlation between 12-month SPECT uptake and preceding BMD change in medial tibia (r = 0.5, P = 0.044). At 12 months, SPECT uptakes in the operated knee were notably higher compared with those of the control knee. SPECT uptakes showed statistically significant decreases from 12 months to 24 months, while SPECT uptake in the control knee remained stable. In tibia, the results are more complex; referring that increased bone remodelling is continuing below the tibial tray. Furthermore, femoral diaphyseal uptake remained elevated, while corresponding tibial uptake had levelled off at 2 years. Increased SPECT uptake during the first 2 years after uncomplicated TKA results most likely from normal postoperative bone remodelling. Levelling of SPECT uptake may indicate a new balance between bone loss and regain.

  18. Effect of nitroglycerin on coronary collateral function during exercise evaluated by quantitative analysis of thallium-201 single photon emission computed tomography

    SciTech Connect

    Aoki, M.; Sakai, K.; Koyanagi, S.; Takeshita, A.; Nakamura, M. )

    1991-05-01

    A noninfarcted, entirely collateral-dependent myocardial region provides an opportunity to assess the effect of nitroglycerin on coronary collateral function during exercise. Stress thallium-201 computed tomography was performed in seven patients with effort angina and no history of myocardial infarction, both before and after nitroglycerin (0.3 mg). All patients had single-vessel disease with total or subtotal (99% with delay) occlusion of proximal left anterior descending coronary artery and well-developed collaterals. The pressure-rate product, mean blood pressure, and heart rate at peak exercise did not differ before and after nitroglycerin. The size of the perfusion defect and the severity of ischemia during exercise estimated by quantitative analysis of thallium-201 single photon emission computed tomography were significantly less after nitroglycerin administration (extent score: 23 +/- 17 vs 7 +/- 9, p less than 0.01; severity score: 20 +/- 22 vs 3 +/- 4, p less than 0.05). The pressure-rate products at peak exercise did not differ before and after nitroglycerin, which suggested that the reduction in perfusion defect size was unlikely to be the result of decreased myocardial oxygen consumption. These results suggest that nitroglycerin improved coronary collateral function during exercise and thus prevented exercise-induced myocardial ischemia.

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

    PubMed Central

    Chakraborty, Dhritiman; Bhattacharya, Anish; Gupta, Ashok Kumar; Panda, Naresh Kumar; Das, Ashim; Mittal, Bhagwant Rai

    2013-01-01

    Background: Skull base osteomyelitis (SBO) refers to infection that has spread beyond the external auditory canal to the base of the skull in advanced stages of otitis externa. Clinically, it may be difficult to differentiate SBO from severe otitis externa without bony involvement. This study was performed to determine the role of three phase bone scintigraphy (TPBS) and single photon emission tomography/computed tomography (SPECT/CT) in detecting SBO. Materials and Methods: We retrospectively analyzed records of 20 patients (14 M, 6 F) with otitis externa and suspected SBO. TPBS and SPECT/CT of the skull were performed. Findings were correlated with clinical, laboratory and diagnostic CT scan findings. Results: All patients were diabetic with elevated erythrocyte sedimentation rate. A total of 18 patients had bilateral and two unilateral symptoms. Cranial nerves were involved in eight patients and microbiological culture of ear discharge fluid positive in seven. Early images showed increased temporal vascularity in nine patients and increased soft-tissue uptake in 10, while delayed images showed increased bone uptake in 19/20 patients. Localized abnormal tracer uptake was shown by SPECT/CT in the mastoid temporal (15), petrous (11), sphenoid (3) and zygomatic (1) and showed destructive changes in five. Thus, TPBS was found positive for SBO in 10/20 patients and changed the management in four. Conclusion: Our study suggests that TPBS with SPECT/CT is a useful non-invasive investigation for detection of SBO in otitis externa. PMID:24163508

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

    PubMed

    Chakraborty, Dhritiman; Bhattacharya, Anish; Gupta, Ashok Kumar; Panda, Naresh Kumar; Das, Ashim; Mittal, Bhagwant Rai

    2013-04-01

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

  1. Dual-single photon emission computed tomography and contrast-enhanced magnetic resonance imaging to evaluate dissimilar features of apical hypertrophic cardiomyopathy.

    PubMed

    Okayama, Satoshi; Kawata, Hiroyuki; Sung, Ji Hee; Okada, Sadanori; Nishida, Taku; Onoue, Kenji; Soeda, Tsunenari; Uemura, Shiro; Saito, Yoshihiko

    2010-01-01

    Apical hypertrophic cardiomyopathy (HCM) is an uncommon variant of HCM characterized by hypertrophy located in the left ventricular apex that occurs at a rate of about 30% in the Japanese population. Although the prognosis of most patients with apical HCM is relatively benign, it can be poor if apical left ventricular aneurysms develop. However, the mechanism of aneurysmal formation is unclear. We describe two patients with apical HCM and dissimilar findings in 201Thallous chloride ((201)TlCl) and (123)I-betamethyl-p-iodophenyl-pentadecanoic acid ((123)I-BMIPP) dual single-photon emission computed tomography (dual-SPECT), but no myocardial fibrosis on contrast-enhanced magnetic resonance images (MRI). One had apparently normal myocardial perfusion and metabolism, whereas the other had exercise-induced myocardial ischemia and impaired myocardial metabolism. These findings indicated that even apical HCM without myocardial fibrosis is pathophysiologically heterogeneous. Apical HCM has been evaluated by either dual-SPECT or cardiac MRI, but not by both. Thus, a combination of imaging modalities is apparently essential for elucidating the pathophysiology of apical HCM. These dissimilar findings in dual-SPECT might be important in identifying patients with apical HCM who are at high risk of forming aneurysms.

  2. Receptor binding characterization of the benzodiazepine radioligand sup 125 I-Ro16-0154: Potential probe for SPECT (Single Photon Emission Computed Tomography) brain imaging

    SciTech Connect

    Johnson, E.W.; Woods, S.W.; Zoghbi, S.; Baldwin, R.M.; Innis, R.B. ); McBride, B.J. )

    1990-01-01

    The binding of an iodinated benzodiazepine (BZ) radioligand has been characterized, particularly in regard to its potential use as a neuroreceptor brain imaging agent with SPECT (Single Photon Emission Computed Tomography). Ro16-0154 is an iodine-containing BZ antagonist and a close analog of Ro15-1788. In tissue homogenates prepared from human and monkey brain, the binding of {sup 125}I-labeled Ro16-0154 was saturable, of high affinity, and had high ratios of specific to non-specific binding. Physiological concentrations of NaCl enhanced specific binding approximately 15% compared to buffer without this salt. Kinetic studies of association and dissociation demonstrated a temperature dependent decrease in affinity with increasing temperature. Drug displacement studies confirmed that {sup 125}I-Ro16-0154 binds to the central type BZ receptor: binding is virtually identical to that of {sup 3}H-Ro15-1788 except that {sup 125}I-Ro16-0154 shows an almost 10 fold higher affinity at 37{degree}C. These in vitro results suggest that {sup 123}I-labeled Ro16-0154 shows promise as a selective, high affinity SPECT probe of the brain's BZ receptor.

  3. Thallium-201 and I-123 beta-methyl iodophenyl-pentadecanoic acid dual isotope single photon emission computed tomography for evaluating reperfusion injury after successful reperfusion therapy.

    PubMed

    Akutsu, Yasushi; Yamanaka, Hideyuki; Nishimura, Hideki; Hamazaki, Yuji; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Suyama, Jumpei; Shinozuka, Akira; Gokan, Takehiko; Kobayashi, Youichi

    2009-04-01

    We report a reperfusion injury after rotational coronary atherectomy (RA) in a 66-year-old man with coronary artery disease. Submaximal exercise with thallium-201 single photon emission computed tomography (SPECT) imaging before reperfusion showed partially reversible perfusion defects in the apex and reversible perfusion defects in the anteroseptal area. Thallium-201 and I-123 beta-methyl iodophenyl-pentadecanoic acid (BMIPP) dual isotope SPECT was performed 5 days before and 1 hour after RA, and 1 month after RA. SPECT images at 1 hour after recovery of no reflow phenomenon after RA revealed enlargement of the defect sizes on thallium-201 and BMIPP uptakes in the anteroseptal area including the apex compared with those before RA. The defect size of thallium-201 uptake was progressively improved on 5 hour delayed redistribution imaging and 1 month after reperfusion compared with that of BMIPP uptake. In conclusion, the changes for the worse of thallium-201 uptake and fatty acid metabolism immediately after the no reflow phenomenon may indicate an injured membrane integrity with altered myocardial metabolism rather than myocardial ischemia. Thallium-201 and I-123 BMIPP dual isotope SPECT is useful for evaluating reperfusion injury after successful reperfusion therapy in a patient with acute coronary syndrome.

  4. Thallium-201 single-photon emission computed tomographic estimates of left ventricular mass in patients with and without ischemic heart disease

    SciTech Connect

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

    1987-07-01

    A new automated edge detection program has been developed to estimate left ventricular mass from single-photon emission computed tomographic (SPECT) thallium-201 images of patients. Left ventricular (LV) mass was measured from contrast angiograms in 21 patients and was compared with LV mass estimated from thallium-201 tomographic studies. A comparison of angiographic mass to mass estimated from stress studies yielded an r = 0.97 (SEE = 21.6 gm) and a comparison of angiographic mass to mass determined from the redistribution images yielded r = 0.96 (SEE = 23.0 gm). Values of mass from stress and redistribution studies varied 7.3% +/- 6.7 and 8.8% +/- 9.2, respectively, when compared with values obtained by cineangiography. LV mass derived from the stress and redistribution studies were highly correlated (r = 0.97; SEE = 21.9 gm). Linear regression analysis revealed a slope of 1.06 (stress ventricular mass = 1.06 X redistribution mass - 14.9 gm). Thirteen patients had two thallium-201 SPECT studies performed approximately 1 month apart. Estimated LV mass was highly correlated when the two studies were compared (r = 0.94; SEE = 21.7 gm comparing the two stress studies; and r = 0.93, SEE = 19.4 gm for the two redistribution studies). We conclude that SPECT thallium-201 imaging can define LV mass accurately and reproducibly in normal, ischemic, or infarcted tissue.

  5. Improved specificity of myocardial thallium-201 single-photon emission computed tomography in patients with left bundle branch block by dipyridamole

    SciTech Connect

    Burns, R.J.; Galligan, L.; Wright, L.M.; Lawand, S.; Burke, R.J.; Gladstone, P.J. )

    1991-08-15

    Reduced septal uptake of thallium-201 during exercise is frequently observed in patients with left bundle branch block (LBBB) and normal coronary arteries. This may reflect normal coronary autoregulation in response to lower septal oxygen demand; thus, dipyridamole, which uniformly exploits flow reserve, would be more accurate for diagnosis of coronary artery disease (CAD). Sixteen patients with LBBB underwent exercise and dipyridamole thallium-201 single-photon emission computed tomography and coronary angiography within 3 months. Sensitivity for detection of left anterior descending CAD (greater than 50% stenosis) was 0.83 for exercise and 1.00 for dipyridamole. Specificity was 0.30 (visual) or 0.20 (quantitative analysis) for exercise and 0.80 (visual) or 0.90 (quantitative) for dipyridamole (p less than 0.05). Dipyridamole combined with quantitative analysis also improved specificity of CAD detection overall (p less than 0.01). These data demonstrate that pharmacologic vasodilation is more accurate than exercise when diagnosing CAD by myocardial perfusion scintigraphy in patients with LBBB.

  6. Prediction of left main or 3-vessel disease using myocardial perfusion reserve on dynamic thallium-201 single-photon emission computed tomography with a semiconductor gamma camera.

    PubMed

    Shiraishi, Shinya; Sakamoto, Fumi; Tsuda, Noriko; Yoshida, Morikatsu; Tomiguchi, Seiji; Utsunomiya, Daisuke; Ogawa, Hisao; Yamashita, Yasuyuki

    2015-01-01

    Myocardial perfusion imaging (MPI) may fail to detect balanced ischemia. We evaluated myocardial perfusion reserve (MPR) using Tl dynamic single-photon emission computed tomography (SPECT) and a novel cadmium zinc telluride (CZT) camera for predicting 3-vessel or left main coronary artery disease (CAD). METHODS AND RESULTS: A total of 55 consecutive patients with suspected CAD underwent SPECT-MPI and coronary angiography. The MPR index was calculated using the standard 2-compartment kinetic model. We analyzed the utility of MPR index, other SPECT findings, and various clinical variables. On multivariate analysis, MPR index and history of previous myocardial infarction (MI) predicted left main and 3-vessel disease. The area under the receiver operating characteristic curve was 0.81 for MPR index, 0.699 for history of previous MI, and 0.86 for MPR index plus history of previous MI. MPR index ≤1.5 yielded the highest diagnostic accuracy. Sensitivity, specificity, and accuracy were 86%, 78%, and 80%, respectively, for MPR index, 64%, 76%, 73% for previous MI, and 57%, 93%, and 84% for MPR index plus history of previous MI. Quantification of MPR using dynamic SPECT and a novel CZT camera may identify balanced ischemia in patients with left main or 3-vessel disease.

  7. Retention index of thallium-201 single photon emission computerised tomography (SPECT) as an indicator of metastasis in adenocarcinoma of the lung.

    PubMed Central

    Takekawa, H.; Itoh, K.; Abe, S.; Ogura, S.; Isobe, H.; Sukou, N.; Furudate, M.; Kawakami, Y.

    1994-01-01

    We examined the relationship between the retention of thallium-201 (201Tl) on a delayed scan and the metastatic potential of adenocarcinomas of the lung. We studied 43 patients with adenocarcinoma of the lung and divided them into two groups according to the presence or absence of lymph node metastasis. 201Tl single photon emission computerised tomography (SPECT) was conducted twice: 15 min (early scan) and 120 min (delayed scan) after intravenous injection of 3 mCi of 201Tl chloride. We calculated the retention index in order to evaluate the degree of 201Tl retention in the primary tumour. The retention indices were significantly higher in the group that was positive for lymph node metastasis than in the negative group. In adenocarcinomas with high metastatic potential, 201Tl SPECT demonstrated slow washout or increased retention on the delayed scan. The retention index of 201Tl SPECT is a useful indicator of metastatic potential, thereby facilitating the prediction of prognosis, and provides insight into the relationship between 201Tl uptake and malignancy. This is the first report demonstrating a significant relationship between the retention of 201Tl SPECT and lymph node metastasis. Images Figure 1 PMID:8054281

  8. Influence of left ventricular geometry on thallium-201 gated single-photon emission tomographic findings in patients with known or suspected coronary artery disease.

    PubMed

    Kurisu, Satoshi; Iwasaki, Toshitaka; Ikenaga, Hiroki; Watanabe, Noriaki; Higaki, Tadanao; Shimonaga, Takashi; Ishibashi, Ken; Mitsuba, Naoya; Dohi, Yoshihiro; Kihara, Yasuki

    2014-02-01

    Recent studies have shown good correlations between echocardiography and Tl-201 gated single-photon emission computed tomography (SPECT) for the assessment of left ventricular volumes and ejection fraction. We assessed how left ventricular geometry affected correlations between these values measured by the 2 methods in patients with known or suspected coronary artery disease. There were 109 patients with normal left ventricular geometry, 20 patients with concentric remodeling, 32 patients with eccentric hypertrophy and 28 patients with concentric hypertrophy. In all 4 groups, there were good correlations between end-diastolic volume (EDV) and end-systolic volume (ESV) values measured by echocardiography and quantitative gated SPECT (QGS). EDV and ESV values measured by QGS were significantly underestimated than those measured by echocardiography except for ESV in eccentric hypertrophy. In all 4 groups, ejection fraction (EF) value measured by echocardiography significantly correlated with that measured by QGS, but Bland-Altman plot showed a proportional error. EF value measured by QGS was likely to be overestimated when EF value increased from the median value, and to be underestimated when EF value decreased from the median value especially in concentric remodeling. Tl-201 gated SPECT is a useful tool for the assessment of left ventricular volumes and function, but it requires methodological considerations according to left ventricular geometry.

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

    PubMed

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

    2015-02-04

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

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

    PubMed Central

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

    1997-01-01

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

  11. Quantitative thallium-201 single-photon emission computed tomography during maximal pharmacologic coronary vasodilation with adenosine for assessing coronary artery disease

    SciTech Connect

    Nishimura, S.; Mahmarian, J.J.; Boyce, T.M.; Verani, M.S. )

    1991-09-01

    The diagnostic value of maximal pharmacologic coronary vasodilation with intravenously administered adenosine in conjunction with thallium-201 single-photon emission computed tomography (SPECT) for detection of coronary artery disease was investigated in 101 consecutive patients who had concomitant coronary arteriography. Tomographic images were assessed visually and from computer-quantified polar maps of the thallium-201 distribution. Significant coronary artery disease, defined as greater than 50% luminal diameter stenosis, was present in 70 patients. The sensitivity for detecting patients with coronary artery disease using quantitative analysis was 87% in the total group, 82% in patients without myocardial infarction and 96% in those with prior myocardial infarction; the specificity was 90%. The sensitivity for diagnosing coronary artery disease in patients without infarction with single-, double-and triple-vessel disease was 76%, 86% and 90%, respectively. All individual stenoses were identified in 68% of patients with double-vessel disease and in 65% of those with triple-vessel disease. The extent of the perfusion defects, as quantified by polar maps, was directly related to the extent of coronary artery disease. In conclusion, quantitative thallium-201 SPECT during adenosine infusion has high sensitivity and specificity for diagnosing the presence of coronary artery disease, localizing the anatomic site of coronary stenosis and identifying the majority of affected vascular regions in patients with multivessel involvement.

  12. Value of image fusion using single photon emission computed tomography with integrated low dose computed tomography in comparison with a retrospective voxel-based method in neuroendocrine tumours.

    PubMed

    Amthauer, H; Denecke, T; Rohlfing, T; Ruf, J; Böhmig, M; Gutberlet, M; Plöckinger, U; Felix, R; Lemke, A J

    2005-07-01

    The objective was the evaluation of single photon emission computed tomography (SPECT) with integrated low dose computed tomography (CT) in comparison with a retrospective fusion of SPECT and high-resolution CT and a side-by-side analysis for lesion localisation in patients with neuroendocrine tumours. Twenty-seven patients were examined by multidetector CT. Additionally, as part of somatostatin receptor scintigraphy (SRS), an integrated SPECT-CT was performed. SPECT and CT data were fused using software with a registration algorithm based on normalised mutual information. The reliability of the topographic assignment of lesions in SPECT-CT, retrospective fusion and side-by-side analysis was evaluated by two blinded readers. Two patients were not enrolled in the final analysis because of misregistrations in the retrospective fusion. Eighty-seven foci were included in the analysis. For the anatomical assignment of foci, SPECT-CT and retrospective fusion revealed overall accuracies of 91 and 94% (side-by-side analysis 86%). The correct identification of foci as lymph node manifestations (n=25) was more accurate by retrospective fusion (88%) than from SPECT-CT images (76%) or by side-by-side analysis (60%). Both modalities of image fusion appear to be well suited for the localisation of SRS foci and are superior to side-by-side analysis of non-fused images especially concerning lymph node manifestations.

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

    NASA Astrophysics Data System (ADS)

    Prince, John R.

    1982-12-01

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

  14. Combined transbronchial needle aspiration and (99m)Tc-2-methoxy-isobutyl-isonitrile single photon emission computed tomography for diagnosing enlarged mediastinal lymph nodes.

    PubMed

    Fiorelli, Alfonso; Rambaldi, Pierfrancesco; Vicidomini, Giovanni; di Serio, Umberto; Accardo, Marina; Rotondo, Antonio; Santini, Mario

    2014-01-01

    To demonstrate the diagnostic accuracy of an integrated approach of blind trans-bronchial needle aspiration (TBNA) and (99m)Tc-2-methoxy-isobutyl-isonitrile single photon emission computed tomography ((99m)Tc-MIBI-SPECT) in diagnosing mediastinal lymph adenopathy. Sixty one consecutive patients with mediastinal lymph adenopathy undergoing both TBNA and (99m)Tc-MIBI-SPECT were prospectively enrolled. Mediastinoscopy was attended in case of negative TBNA. Eighty three adenopathies were sampled (73 malignant and 10 benign). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of TBNA was 74%, 100%, 100%, and 34%, respectively; and of (99m)Tc-MIBI-SPECT was 96%, 80%, 97%, and 73%, respectively. Combining TBNA and (99m)Tc-MIBI-SPECT results sensitivity, specificity, PPV, NPV of 97%, 100%, 100%, and 83%, respectively, was obtained. TBNA alone avoided medistianoscopy in 65% of cases, while an integrated approach could have potentially obviated mediastinoscopy in 76%. (99m)Tc-MIBI-SPECT improved the sensitivity and the NPV of TBNA, reducing the need of mediastinoscopy. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

  15. Chlorotoxin-Conjugated Multifunctional Dendrimers Labeled with Radionuclide 131I for Single Photon Emission Computed Tomography Imaging and Radiotherapy of Gliomas.

    PubMed

    Zhao, Lingzhou; Zhu, Jingyi; Cheng, Yongjun; Xiong, Zhijuan; Tang, Yueqin; Guo, Lilei; Shi, Xiangyang; Zhao, Jinhua

    2015-09-09

    Chlorotoxin-conjugated multifunctional dendrimers labeled with radionuclide 131I were synthesized and utilized for targeted single photon emission computed tomography (SPECT) imaging and radiotherapy of cancer. In this study, generation five amine-terminated poly(amidoamine) dendrimers were used as a platform to be sequentially conjugated with polyethylene glycol (PEG), targeting agent chlorotoxin (CTX), and 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO). This was followed by acetylation of the remaining dendrimer terminal amines and radiolabeling with 131I to form the targeted theranostic dendrimeric nanoplatform. We show that the dendrimer platform possessing approximately 7.7 CTX and 21.1 HPAO moieties on each dendrimer displays excellent cytocompatibility in a given concentration range (0-20 μM) and can specifically target cancer cells overexpressing matrix metallopeptidase 2 (MMP2) due to the attached CTX. With the attached HPAO moiety having the phenol group, the dendrimer platform can be effectively labeled with radioactive 131I with good stability and high radiochemical purity. Importantly, the 131I labeling renders the dendrimer platform with an ability to be used for targeted SPECT imaging and radiotherapy of an MMP2-overexpressing glioma model in vivo. The developed radiolabeled multifunctional dendrimeric nanoplatform may hold great promise to be used for targeted theranostics of human gliomas.

  16. N-isopropyl(I-123)p-lodoamphetamine brain scans with single-photon emission tomography discordance with transmission computed tomography

    SciTech Connect

    Lee, R.G.; Hill, T.C.; Holman, B.L.; Clouse, M.E.

    1982-12-01

    Transmission computed tomography (CT) brain scans were compared with N-isopropyl (I-123)p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) brain scans to determine if there was a correlation between morphology, as seen on CT, and cerebral perfusion changes detected by IMP SPECT. In 12 patients with acute stroke, four showed no discordance between the edema seen on CT and perfusion deficits seen on IMP SPECT; five had positive IMP scans while initial CT scans were negative and follow-up CT scans demonstrated edema in the region of perfusion deficit seen on the IMP scans; and in four patients, the average perfusion deficit was 2.3 times greater than the edema shown on CT at 2 cm above the canthalmeatal line. In nine control patients, there was a 2.3% difference in IMP activity between the right and left hemispheres. The 12 stroke patients showed 30.3% less IMP activity in the abnormal hemisphere compared with the normal side. Three patients, one with temporal lobe seizure, one with hemiballismus, and the third with idiopathic intention tumor, had 54% greater IMP activity on the side of movement or seizure than on the normal side. The discordance between IMP and CT scans was clearly demonstrated in cases in which CT showed no abnormality but IMP provided information on function, reflected in increased or decreased cerebral perfusion.

  17. N-isopropy(/sup 123/I)p-iodoamphetamine brain scans with single-photon emission tomagraphy: discordacne with transmission computed tomography

    SciTech Connect

    Lee, R.G.; Hill, T.C.; Holman, B.L.; Clouse, M.E.

    1982-12-01

    Transmission computed tomography (CT) brain scans were compared with N-isopropyl (/sup 123/I)-p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) brain scans to determine if there was a correlation between morphology, as seen on CT, and cerebral perfusion changes detected by IMP SPECT. In 12 patients with acute stroke, four showed no discordance between the edema seen on CT and perfusion deficits seen on IMP SPECT; five had positive IMP scans while initial CT scans were negative and follow-up CT scans demonstrated edema in the region of perfusion deficit seen on the IMP scans; and in four patients, the average perfusion deficit was 2.3 times greater than the edema shown on CT at 2 cm above the canthal-meatal line. In nine control patients, there was a 2.3% difference in IMP activity between the right and left hemispheres. The 12 stroke patients showed 30.3% less IMP activity in the abnormal hemisphere compared with the normal side. Three patients, one with temporal lobe seizure, one with hemiballismus, and the third with idiopathic intention tumor, had 54% greater IMP activity on the side of movement or seizure than on the normal side. The discordance between IMP and CT scans was clearly demonstrated in cases in which CT showed no abnormality but IMP provided information on function, reflected in increased or decreased cerebral perfusion.

  18. Prediction of pulmonary function after lung lobectomy by subsegments counting, computed tomography, single photon emission computed tomography and computed tomography: a comparative study.

    PubMed

    Yoshimoto, Kentaro; Nomori, Hiroaki; Mori, Takeshi; Kobayashi, Hironori; Ohba, Yasuomi; Shibata, Hidekatsu; Shiraishi, Shinya; Kobayashi, Toshiaki

    2009-03-01

    The aim of the present study was to determine the optimal method of predicting postoperative pulmonary function (PPF) after lung lobectomy. The forced expiratory volume in 1s (FEV(1)) was measured in 37 patients before and after lobectomy, and the following three methods of predicting the PPF were evaluated: (1) the number of functioning subsegments to be resected were counted (subsegments counting [SC]); (2) the volume of the functioning lung was calculated using CT images (quantitative CT); and (3) perfusion scintigraphy was performed using co-registered single photon emission computed tomography and CT imaging (SPECT/CT). The FEV(1) values predicted using these three methods were then compared with the measured postoperative FEV(1), and the correlations and differences were analyzed. While a paired t-test showed the SPECT/CT method to have the smallest difference between the measured and the predicted FEV(1) values (0.05 l, p=0.33), followed by the quantitative CT method (0.07 l, p=0.07), and finally the SC method (0.15 l, p<0.001), the difference between the two values was not significantly different between the quantitative CT and SPECT/CT method (p=0.22). While the SC method is inferior to both the quantitative CT and the SPECT/CT methods for predicting the PPF after lobectomy, the latter two methods are almost equally accurate.

  19. Cerebral-perfusion-based single-photon emission computed tomography (SPECT) staging using NeuroGam® in patients with moyamoya disease.

    PubMed

    Han, Jai-Hyuck; Park, Young Seok; Lee, Won Hyoung; Koong, Sung-Soo; Min, Kyung-Soo; Lee, Mou-Seop; Kim, Young-Gyu; Kim, Dong-Ho; Yi, Kyung-Sil; Cha, Sang-Hoon

    2016-08-01

    Cerebral angiography (CA) is the gold standard for moyamoya disease (MMD) staging and diagnosis, but CA findings are not well correlated with clinical symptoms. The purpose of this study was to establish novel cerebral-perfusion-based staging for MMD that is well correlated with clinical symptoms. From 2010 to 2015, regional cerebrovascular reserve (rCVR) was examined by single-photon emission computed tomography (SPECT) using NeuroGam® (Segamicorp, Houston, TX, USA) in 30 patients (17 women, 13 men; 60 hemispheres; mean 42.0 years old [range 5-60 years old]) with MMD, which was diagnosed by CA and magnetic resonance angiography (MRA). Brain CT or brain magnetic resonance imaging (MRI) was used to evaluate neurological conditions such as transient ischemic attack (TIA), cerebral hemorrhage, and cerebral infarction. A novel staging system for MMD was developed by combining findings from CA, MRI, and SPECT with NeuroGam®. Our novel staging system was strongly associated with clinical symptoms. Twenty-two hemispheres out of 60 were categorized as stage I, 24 hemispheres were categorized as stage II, and 14 hemispheres were categorized as stage III. Hemispheres with higher scores exhibited a higher incidence of clinical symptoms. These findings indicate that cerebral-perfusion-based staging is predictive of MMD clinical symptoms. Perfusion-based SPECT staging correlates well with clinical symptoms and may be a reliable alternative to the Suzuki staging by CA.

  20. High-Resolution 4D Preclinical Single-Photon Emission Computed Tomography/X-ray Computed Tomography Imaging of Technetium Transport within a Heterogeneous Porous Media.

    PubMed

    Dogan, Mine; Moysey, Stephen M J; Ramakers, Ruud M; DeVol, Timothy A; Beekman, Frederik J; Groen, Harald C; Powell, Brian A

    2017-03-07

    A dynamic (99m)Tc tracer experiment was performed to investigate the capabilities of combined preclinical single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) for investigating transport in a heterogeneous porous medium. The experiment was conducted by continuously injecting a (99m)Tc solution into a column packed with eight layers (i.e., soil, silica gel, and 0.2-4 mm glass beads). Within the imaging results it was possible to correlate observed features with objects as small as 2 mm for the SPECT and 0.2 mm for the CT. Time-lapse SPECT imaging results illustrated both local and global nonuniform transport phenomena and the high-resolution CT data were found to be useful for interpreting the cause of variations in the (99m)Tc concentration associated with structural features within the materials, such as macropores. The results of this study demonstrate SPECT/CT as a novel tool for 4D (i.e., transient three-dimensional) noninvasive imaging of fate and transport processes in porous media. Despite its small scale, an experiment with such high resolution data allows us to better understand the pore scale transport which can then be used to inform larger scale studies.

  1. Prognostic value of lower limb perfusion single-photon emission computed tomography-computed tomography in patients with lower limb atherosclerotic peripheral artery disease.

    PubMed

    Hashimoto, Hidenobu; Fukushima, Yoshimitsu; Kumita, Shin-Ichiro; Miyamoto, Masaaki; Takagi, Gen; Yamazaki, Junichi; Ikeda, Takanori

    2017-02-01

    The purpose of this study was to estimate the severity of the participants' lower limb ischemia by calculating the lower limb muscle-to-background ratio (LMBR) using lower limb perfusion single-photon emission computed tomography-computed tomography (SPECT/CT) and to evaluate the prognostic value of LMBR in peripheral artery disease (PAD) patients. This retrospective study consists of 38 patients with PAD (70 ± 12 years) and observed over 1 year who were included in the analysis. All participants underwent lower limb perfusion SPECT/CT. LMBR was calculated by dividing counts/volume in lower limb muscle by mean counts/volume of background. All patients were divided into two groups based on their LMBR value and observed for the occurrence of a major adverse event (MAE). The high and low LMBR groups consisted of 26 and 12 patients, respectively. The median LMBR in the high group was 9.59 (6.11-11.87) while that in the low group was 4.35 (3.85-4.99). A significantly higher number of patients in the low LMBR group experienced MAE than in the high LMBR group (7 of 12 vs. 1 of 26, p < 0.001). This study demonstrated that the LMBR derived from lower limb perfusion SPECT/CT may have a high prognostic value in patients with PAD.

  2. Diagnostic advantage of stress computed tomography myocardial perfusion over single-photon emission computed tomography for the assessment of myocardial ischemia.

    PubMed

    Ueki, Yasushi; Izawa, Atsushi; Kashiwagi, Daisuke; Nishiyama, Shigeki; Aso, Shinichi; Suzuki, Chihiro; Sakurai, Shumpei; Oguchi, Kazuhiro; Yazaki, Yoshikazu; Ikeda, Uichi; Kuwahara, Koichiro

    2017-08-01

    This study compared adenosine stress computed tomography myocardial perfusion (CTP) with single-photon emission computed tomography (SPECT) in the diagnosis of functionally significant coronary artery stenosis using fractional flow reserve (FFR) as reference standard. We included a total of 93 coronary arteries from 31 patients in whom at least one vessel with ≥50% stenosis was detected with computed tomography coronary angiography. All patients underwent both SPECT and adenosine stress CTP, followed by invasive coronary angiography (ICA) and FFR. Diagnostic accuracy between CTP and SPECT was compared according to positive findings of either ≥99% stenosis on ICA or FFR ≤0.8. Among 78 vessels eligible for the quantitative analyses, significant coronary artery disease (CAD) was diagnosed in 22 vessels of 19 patients. Comparison of CTP vs. SPECT for sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy in detecting significant CAD were 59% vs. 18%, 96% vs. 93%, 87% vs. 50%, 86% vs. 74%, and 86% vs. 72%, respectively. CTP demonstrated a significant diagnostic advantage over SPECT in the identification of significant CAD, especially in terms of sensitivity and PPV. Adenosine stress CTP is useful for the noninvasive diagnosis of functionally significant CAD. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  3. Extensive brain infarction involving deep structures during an acetazolamide-challenged single-photon emission computed tomography scan in a patient with moyamoya disease.

    PubMed

    Chong, Sangjoon; Park, June Dong; Chae, Jong Hee; Cheon, Jung-Eun; Kim, Seung-Ki; Phi, Ji Hoon; Lee, Ji Yeoun; Paeng, Jin Chul; Wang, Kyu-Chang

    2017-07-08

    Acetazolamide-challenged brain single-photon emission computed tomography (SPECT) is used for the evaluation of cerebral perfusion in cerebrovascular diseases including moyamoya disease (MMD). Not a few patients experience adverse side effects during the acetazolamide-challenged brain SPECT, but most of the symptoms are mild and transient. To our knowledge, this is the first case report of severe brain infarction leading to death during the examination of an acetazolamide-challenged brain SPECT in a patient with MMD. An 11-year-old girl who had been diagnosed of MMD demonstrated sudden tonic movement during an acetazolamide-challenged brain SPECT as the preoperative examination for the second surgery. She had not experienced any adverse effect during the previous SPECT study and her first indirect bypass surgery on both left side and bifrontal area was uneventful. After she had seizures twice, she became unconscious and her pupils were dilated and fixed. Acute infarction involving bilateral occipital lobes, thalami, brainstem, and cerebellum was observed on brain magnetic resonance images which led to brain death. We report a mortality case of patient with MMD after the administration of acetazolamide during the examination of brain SPECT that was accompanied by an extensive acute infarction involving the bilateral occipital lobes and thalami, brainstem, and cerebellum. Physicians should be aware of this rare but serious complication.

  4. Detection rate of (99m) Tc-MIBI single photon emission computed tomography (SPECT)/CT in preoperative planning for patients with primary hyperparathyroidism: A meta-analysis.

    PubMed

    Treglia, Giorgio; Sadeghi, Ramin; Schalin-Jäntti, Camilla; Caldarella, Carmelo; Ceriani, Luca; Giovanella, Luca; Eisele, David W

    2016-04-01

    Parathyroid scintigraphy using (99m) Tc-MIBI single photon emission computed tomography (SPECT)/CT has been proposed as one of the most accurate localization techniques in patients with primary hyperparathyroidism (PHPT). The purpose of this review was to meta-analyze published data on the detection rate of (99m) Tc-MIBI SPECT/CT in the preoperative planning of patients with PHPT. A comprehensive literature search of studies published through June 2014 was performed. The pooled detection rate of this scintigraphic method including 95% confidence intervals (95% CIs) was calculated on a per patient-based and on a per lesion-based analysis by using a random effects model. Twenty-three articles including 1236 patients with PHPT were selected. The pooled detection rate of (99m) Tc-MIBI SPECT/CT in the preoperative planning of patients with PHPT was 88% (95% CI = 84% to 92%) and 88% (95% CI = 82% to 92%) on a per patient-based and per lesion-based analysis, respectively. The (99m) Tc-MIBI SPECT/CT has high detection rate for hyperfunctioning parathyroid glands in patients with PHPT. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2159-E2172, 2016. © 2015 Wiley Periodicals, Inc.

  5. [Single-photon emission computed tomography for the diagnosis of mandibular invasion caused by oral cancers: a systematic review and Meta-analysis].

    PubMed

    Xiaonian, Wang; Fenjuan, Luo; Xianghe, Qiao; Wenbin, Yang; Jie, Lin; Chunjie, Li

    2017-08-01

    Objective This review aimed at assessing the diagnostic efficacy of contrast-enhanced single-photon emission computed tomography (SPECT) in the diagnosis of mandibular invasion by oral cancers. Methods Five databases were searched electronically on August 5, 2016. The reference lists of included studies were hand searched. Quality assessment was performed by two reviewers in duplicate with tools suggested by Cochrane's handbook. Furthermore, the data extraction of included studies was delivered. Meta-analysis was performed using STATA 11.0. Results Ten studies with 460 participants were included. One study had a low risk of bias, and two studies had a high risk of bias. The remaining seven studies had an unclear risk of bias. Meta-analysis results showed that SPECT had a pooled sensitivity of 0.99 [95% confidence interval=0.87-
1.00]. Sensitivity was 0.99 on Q* point. The specificity of 0.61 and the area under summary receiver operating characteristic curve (SROC) were 0.93 [95% confidence interval=0.90-
0.95]. The pooled positive likelihood ratio was 2.555. The negative likelihood ratio was 0.015. The diagnostic odd ratio was 5.115. Conclusion SPECT had high sensitivity, which became suitable for excluding bone invasion by oral cancers. However, its specificity was relatively low, indicating its limited capability in confirming diagnosis. Therefore, surgeons should perform this method under certain conditions.

  6. Impact of cardiac hybrid single-photon emission computed tomography/computed tomography imaging on choice of treatment strategy in coronary artery disease

    PubMed Central

    Pazhenkottil, Aju P.; Nkoulou, Rene N.; Ghadri, Jelena-Rima; Herzog, Bernhard A.; Küest, Silke M.; Husmann, Lars; Wolfrum, Mathias; Goetti, Robert; Buechel, Ronny R.; Gaemperli, Oliver; Lüscher, Thomas F.; Kaufmann, Philipp A.

    2011-01-01

    Aims Cardiac hybrid imaging by fusing single-photon emission computed tomography (SPECT) myocardial perfusion imaging with coronary computed tomography angiography (CCTA) provides important complementary diagnostic information for coronary artery disease (CAD) assessment. We aimed at assessing the impact of cardiac hybrid imaging on the choice of treatment strategy selection for CAD. Methods and results Three hundred and eighteen consecutive patients underwent a 1 day stress/rest 99mTc-tetrofosmin SPECT and a CCTA on a separate scanner for evaluation of CAD. Patients were divided into one of the following three groups according to findings in the hybrid images obtained by fusing SPECT and CCTA: (i) matched finding of stenosis by CCTA and corresponding reversible SPECT defect; (ii) unmatched CCTA and SPECT finding; (iii) normal finding by both CCTA and SPECT. Follow-up was confined to the first 60 days after hybrid imaging as this allows best to assess treatment strategy decisions including the revascularization procedure triggered by its findings. Hybrid images revealed matched, unmatched, and normal findings in 51, 74, and 193 patients. The revascularization rate within 60 days was 41, 11, and 0% for matched, unmatched, and normal findings, respectively (P< 0.001 for all inter-group comparisons). Conclusion Cardiac hybrid imaging with SPECT and CCTA provides an added clinical value for decision making with regard to treatment strategy for CAD. PMID:21804107

  7. 99mTc-Hexamethyl Propyleneamine Oxime Brain Perfusion Single Photon Emission Computed Tomography in Characterization of Dementia: An Initial Experience in Indian Clinical Practice

    PubMed Central

    Santra, Amburanjan; Sinha, Gaurav Kumar; Neogi, Rajarshi; Thukral, Ramesh Kumar

    2014-01-01

    There is a growing health burden in developing countries due to recent trends of increasing incidence of neurodegenerative diseases. To reduce the healthcare cost and effective management of dementia illness, early diagnosis, accurate differentiation and their progression assessment is becoming crucially important. We are utilizing 99mTc-d, l-hexamethyl propyleneamine oxime (HMPAO) brain perfusion single photon emission computed tomography (SPECT) to characterize dementia on the basis of perfusion patterns and observed significant improvement in their management. Eleven patients (median age of 60 years range of 53-83 years) with clinical suspicion of dementia underwent 99mTc-HMPAO brain perfusion SPECT. SPECT-computed tomography acquisition done, data are reconstructed, reviewed in three view and further processed in “neurogam” to get voxel based analysis and the comparison with age based normal database and surface mapping. Final diagnosis was done with clinical correlation. Four patients are diagnosed as Alzheimer's disease, two as frontotemporal dementia, one as dementia of Lewy bodies, two as vascular dementia and two as pseudodementia. All imaging findings are well-correlated with clinical background. Brain perfusion SPECT with HMPAO was very helpful to us in characterizing the patients of dementia by its perfusion pattern. PMID:25191127

  8. Safety and biodistribution of 111In-amatuximab in patients with mesothelin expressing cancers using single photon emission computed tomography-computed tomography (SPECT-CT) imaging.

    PubMed

    Lindenberg, Liza; Thomas, Anish; Adler, Stephen; Mena, Esther; Kurdziel, Karen; Maltzman, Julia; Wallin, Bruce; Hoffman, Kimberly; Pastan, Ira; Paik, Chang Hum; Choyke, Peter; Hassan, Raffit

    2015-02-28

    Amatuximab is a chimeric high-affinity monoclonal IgG1/k antibody targeting mesothelin that is being developed for treatment of mesothelin-expressing cancers. Considering the ongoing clinical development of amatuximab in these cancers, our objective was to characterize the biodistribution, and dosimetry of 111Indium (111In) radiolabelled amatuximab in mesothelin-expressing cancers. Between October 2011 and February 2013, six patients including four with malignant mesothelioma and two with pancreatic adenocarcinoma underwent Single Photon Emission Computed Tomography-Computed Tomography (SPECT/CT) imaging following administration of 111In amatuximab. SPECT/CT images were obtained at 2-4 hours, 24-48 hours and 96-168 hours after radiotracer injection. In all patients, tumor to background ratios (TBR) consistently met or exceeded an uptake of 1.2 (range 1.2-62.0) which is considered the minimum TBR that can be visualized. TBRs were higher in tumors of patients with mesothelioma than pancreatic adenocarcinoma. 111In-amatuximab uptake was noted in both primary tumors and metastatic sites. The radiotracer dose was generally well-tolerated and demonstrated physiologic uptake in the heart, liver, kidneys and spleen. This is the first study to show tumor localization of an anti-mesothelin antibody in humans. Our results show that 111In-amatuximab was well tolerated with a favorable dosimetry profile. It localizes to mesothelin expressing cancers with a higher uptake in mesothelioma than pancreatic cancer.

  9. Optimization of helical acquisition parameters to preserve uniformity of mouse whole body using multipinhole collimator in single-photon emission computed tomography

    NASA Astrophysics Data System (ADS)

    Ukon, Naoyuki; Kubo, Naoki; Ishikawa, Masayori; Zhao, Songji; Tamaki, Nagara; Kuge, Yuji

    Focusing on whole-body uniformity in small-animal single-photon emission computed tomography (SPECT), we examined the optimal helical acquisition parameters using five-pinhole collimators for mouse imaging. SPECT images of an 80-mm-long cylindrical phantom with 99mTc solution were acquired using an Inveon multimodality imaging platform. The bed travels used in this study were 0, 30, 60, 90 and 120 mm, and the numbers of revolutions traversed during the SPECT scan were 1.0, 2.0, 3.0, 4.0, 5.0 and 7.0, respectively. Artifacts that degrade uniformity in reconstructed images were conspicuous when the bed travel was smaller than the object length. Regarding the distal-to-center ratio (DCR) of SPECT values in the object's axial direction, the DCR nearest to the ideal ratio of 1.00 was 1.02 in the optimal uniformity with 4.0 revolutions and a bed travel of 120 mm. Moreover, the helical acquisition using these parameters suppressed the formation of artifacts. We proposed the optimal parameters in whole-body helical SPECT; the bed travel was sufficiently larger than the object length; the 4.0 or more revolutions were required for a pitch of approximately 30 mm/revolution. The optimal acquisition parameters in SPECT to preserve uniformity would contribute to the accurate quantification of whole-body biodistribution.

  10. Relation of gender to physician use of test results and to the prognostic value of stress technetium 99m sestamibi myocardial single-photon emission computed tomography scintigraphy.

    PubMed

    Travin, M I; Duca, M D; Kline, G M; Herman, S D; Demus, D D; Heller, G V

    1997-07-01

    We analyzed potential gender differences in the use and prognostic value of stress technetium 99m sestamibi tomography, image results, and cardiac event rates over a period of 15 +/- 8 months in 1226 men and 1151 women. Men had more abnormal tomographic images, but referral for catheterization and revascularization similarly increased in relation to the number of defects. Men and women with abnormal images had similar event rates, 19.6% and 18.2%, respectively, although men more often had myocardial infarction or cardiac death (7.6% vs 4.1 %, p < 0.05), whereas women had an increased likelihood of unstable angina or congestive heart failure (11.5% vs 7.6%, p < 0.05). Normal images predicted a low yearly rate of myocardial infarction or death: 1.7% for men and 0.8% for women. Image findings, particularly defect extent, were independent predictors of events in both groups. Thus, after stress Tc-99m sestamibi single-photon emission computed tomography perfusion imaging, there was no gender bias in referral for invasive procedures, and for both men and women image findings were strongly associated with prognostic outcome.

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

    SciTech Connect

    Zannad, F.; Amor, M.; Karcher, G.; Maurin, P.; Ethevenot, G.; Sebag, C.; Bertrand, A.; Pernot, C.; Gilgenkrantz, J.M.

    1988-06-01

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

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

    SciTech Connect

    Kugiyama, K.; Yasue, H.; Okumura, K.; Minoda, K.; Takaoka, K.; Matsuyama, K.; Kojima, A.; Koga, Y.; Takahashi, M.

    1987-11-01

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

  13. Coregistration of magnetic resonance and single photon emission computed tomography images for noninvasive localization of stem cells grafted in the infarcted rat myocardium.

    PubMed

    Shen, Dinggang; Liu, Dengfeng; Cao, Zixiong; Acton, Paul D; Zhou, Rong

    2007-01-01

    This paper demonstrates the application of mutual information based coregistration of radionuclide and magnetic resonance imaging (MRI) in an effort to use multimodality imaging for noninvasive localization of stem cells grafted in the infarcted myocardium in rats. Radionuclide imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) inherently has high sensitivity and is suitable for tracking of labeled stem cells, while high-resolution MRI is able to provide detailed anatomical and functional information of myocardium. Thus, coregistration of PET or SPECT images with MRI will map the location and distribution of stem cells on detailed myocardium structures. To validate this coregistration method, SPECT data were simulated by using a Monte Carlo-based projector that modeled the pinhole-imaging physics assuming nonzero diameter and photon penetration at the edge. Translational and rotational errors of the coregistration were examined with respect to various SPECT activities, and they are on average about 0.50 mm and 0.82 degrees , respectively. Only the rotational error is dependent on activity of SPECT data. Stem cells were labeled with (111)Indium oxyquinoline and grafted in the ischemic myocardium of a rat model. Dual-tracer small-animal SPECT images were acquired, which allowed simultaneous detection of (111)In-labeled stem cells and of [(99m)Tc]sestamibi to assess myocardial perfusion deficit. The same animals were subjected to cardiac MRI. A mutual-information-based coregistration method was then applied to the SPECT and MRIs. By coregistration, the (111)In signal from labeled cells was mapped into the akinetic region identified on cine MRIs; the regional perfusion deficit on the SPECT images also coincided with the akinetic region on the MR image.

  14. Non-Uniform Object-Space Pixelation (NUOP) for Penalized Maximum-Likelihood Image Reconstruction for a Single Photon Emission Microscope System

    PubMed Central

    Meng, L. J.; Li, Nan

    2016-01-01

    This paper presents a non-uniform object-space pixelation (NUOP) approach for image reconstruction using the penalized maximum likelihood methods. This method was developed for use with a single photon emission microscope (SPEM) system that offers an ultrahigh spatial resolution for a targeted local region inside mouse brain. In this approach, the object-space is divided with non-uniform pixel sizes, which are chosen adaptively based on object-dependent criteria. These include (a) some known characteristics of a target-region, (b) the associated Fisher Information that measures the weighted correlation between the responses of the system to gamma ray emissions occurred at different spatial locations, and (c) the linear distance from a given location to the target-region. In order to quantify the impact of this non-uniform pixelation approach on image quality, we used the Modified Uniform Cramer-Rao bound (MUCRB) to evaluate the local resolution-variance and bias-variance tradeoffs achievable with different pixelation strategies. As demonstrated in this paper, an efficient object-space pixelation could improve the speed of computation by 1–2 orders of magnitude, whilst maintaining an excellent reconstruction for the target-region. This improvement is crucial for making the SPEM system a practical imaging tool for mouse brain studies. The proposed method also allows rapid computation of the first and second order statistics of reconstructed images using analytical approximations, which is the key for the evaluation of several analytical system performance indices for system design and optimization.

  15. Single-photon and photon pair emission from MOVPE-grown In(Ga)As quantum dots: shifting the emission wavelength from 1.0 to 1.3 μm

    NASA Astrophysics Data System (ADS)

    Kettler, Jan; Paul, Matthias; Olbrich, Fabian; Zeuner, Katharina; Jetter, Michael; Michler, Peter

    2016-03-01

    InAs quantum dots grown on a GaAs substrate have been one of the most successful semiconductor material systems to demonstrate single-photon-based quantum optical phenomena. In this context, we present the feasibility to extend the low-temperature photoluminescence emission range of In(Ga)As/GaAs quantum dots grown by metal-organic vapor-phase epitaxy from the typical window between 880 and 960 nm to wavelengths above 1.3 μm. A low quantum dot density can be obtained throughout this range, enabling the demonstration of single- and cascaded photon emission. We further analyze polarization-resolved micro-photoluminescence from a large number of individual quantum dots with respect to anisotropy and size of the underlying fine-structure splittings in the emission spectra. For samples with elevated emission wavelengths, we observe an increasing tendency of the emitted photons to be polarized along the main crystal axes.

  16. Quantification of infarct size by /sup 201/Tl single-photon emission computed tomography during acute myocardial infarction in humans. Comparison with enzymatic estimates

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Borges-Neto, S.; Cashion, W.R.; Roberts, R.; Verani, M.S.

    1988-10-01

    We prospectively investigated whether /sup 201/Tl single-photon emission computed tomography (SPECT) could accurately diagnose the presence and quantify the extent of acute myocardial infarction when compared with infarct size assessed by plasma MB-creatine kinase activity. Thirty patients with enzymatic evidence of infarction were imaged within 12-36 hours of chest pain (mean, 23.4 hours). No patient had a previous infarction, and none underwent intervention seeking to restore coronary patency. Infarct size was quantified with computer-generated polar maps of the myocardial radioactivity and expressed as a percentage of the total left ventricular volume. To assess left and right ventricular performance, blood-pool gated radionuclide angiography was performed immediately after SPECT. All 30 patients had perfusion defects consistent with myocardial infarction. Scintigraphic and enzymatic estimates of infarct size correlated well for the group as a whole (r = 0.78, p less than 0.001, SEE = 9.1) but especially for those patients with anterior infarction (r = 0.91, p less than 0.001, SEE = 7.9). The poor correlation observed in patients with inferior infarction (r = 0.50, p less than 0.05, SEE = 10.0) was believed to be related to the frequent occurrence of right ventricular involvement because SPECT assessed only left ventricular damage, whereas the enzymatic method estimated the myocardial injury in both ventricles. A quantitative index of right ventricular infarct size, derived from the relation between the scintigraphic and enzymatic estimates, had a strong inverse correlation with right ventricular ejection fraction (r = -0.89, p less than 0.001, SEE = 3.6).

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

    SciTech Connect

    Cheng, D.C.; Chung, F.; Burns, R.J.; Houston, P.L.; Feindel, C.M. )

    1989-12-01

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

  18. Quantification of myocardial infarction: a comparison of single photon-emission computed tomography with pyrophosphate to serial plasma MB-creatine kinase measurements

    SciTech Connect

    Jansen, D.E.; Corbett, J.R.; Wolfe, C.L.; Lewis, S.E.; Gabliani, G.; Filipchuk, N.; Redish, G.; Parkey, R.W.; Buja, L.M.; Jaffe, A.S.

    1985-08-01

    Single photon-emission computed tomography (SPECT) with /sup 99m/Tc-pyrophosphate (PPi) has been shown to estimate size of myocardial infarction accurately in animals. The authors tested the hypothesis that SPECT with /sup /sup 99m//Tc-PPi and blood pool subtraction can provide prompt and accurate estimates of size of myocardial infarction in patients. SPECT estimates are potentially available early after the onset of infarction and should correlate with estimates of infarct size calculated from serial measurements of plasma MB-creatine kinase (CK) activity. Thirty-three patients with acute myocardial infarction and 16 control patients without acute myocardial infarction were studied. Eleven of the patients had transmural anterior myocardial infarction, 16 had transmural inferior myocardial infarction, and six had nontransmural myocardial infarction. SPECT was performed with a commercially available rotating gamma camera. Identical projection images of the distribution of 99mTc-PPi and the ungated cardiac blood pool were acquired sequentially over 180 degrees. Reconstructed sections were color coded and superimposed for purposes of localization of infarct. Areas of increased PPi uptake within myocardial infarcts were thresholded at 65% of peak activity. The blood pool was thresholded at 50% and subtracted to determine the endocardial border for the left ventricle. Myocardial infarcts ranged in size from 1 to 126 gram equivalents (geq) MB-CK. The correlation of MB-CK estimates of size of infarct with size determined by SPECT (both in geq) was good (r = .89 with a regression line of y = 13.1 + 1.5x).

  19. Functional significance of myocardial perfusion defects induced by dipyridamole using thallium-201 single-photon emission computed tomography and two-dimensional echocardiography

    SciTech Connect

    Jain, A.; Suarez, J.; Mahmarian, J.J.; Zoghbi, W.A.; Quinones, M.A.; Verani, M.S. )

    1990-10-01

    The mechanisms responsible for inhomogeneous myocardial blood flow after oral administration of a large dose (300 mg) of dipyridamole were assessed in 27 patients with serial thallium-201 single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiograms. Myocardial tomographic images were obtained 50 minutes and 3 to 4 hours after administration of dipyridamole. Two-dimensional echocardiograms were recorded at baseline and then every 15 minutes for 60 minutes. Dipyridamole caused only a mild reduction in blood pressure (from 129 +/- 18 to 126 +/- 16 mm Hg) and a mild increase in heart rate (from 69 +/- 15 to 73 +/- 4 beats/min). Sixteen patients had perfusion defects after dipyridamole by SPECT, which underwent partial or total filling-in. Fourteen of these patients (87.5%) had either a new abnormality or further deterioration of a preexisting wall motion abnormality by 2-dimensional echocardiography, and thus were considered to have developed transient ischemia during dipyridamole administration. Ten of 11 patients (91%) with normal perfusion or fixed defects by SPECT had no further deterioration in wall motion after oral dipyridamole, and were thus considered to have no evidence of myocardial ischemia. In conclusion, most patients with transient thallium-201 defects after dipyridamole develop transient worsening of resting wall motion by 2-dimensional echocardiography, suggestive of true myocardial ischemia. Because myocardial oxygen demand, as indicated by the heart rate-blood pressure product, did not change significantly, the mechanism of myocardial ischemia in these patients is likely to be diminished regional blood flow related to a subendocardial steal induced by dipyridamole.

  20. Altered myocardial perfusion in patients with angina pectoris or silent ischemia during exercise as assessed by quantitative thallium-201 single-photon emission computed tomography

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Cocanougher, M.K.; Verani, M.S. )

    1990-10-01

    The extent of abnormally perfused myocardium was compared in patients with and without chest pain during treadmill exercise from a large, relatively low-risk consecutive patient population (n = 356) referred for quantitative thallium-201 single-photon emission computed tomography (SPECT). All patients had concurrent coronary angiography. Patients were excluded if they had prior coronary angioplasty or bypass surgery. Tomographic images were assessed visually and from computer-generated polar maps. Chest pain during exercise was as frequent in patients with normal coronary arteries (12%) as in those with significant (greater than 50% stenosis) coronary artery disease (CAD) (14%). In the 219 patients with significant CAD, silent ischemia was fivefold more common than symptomatic ischemia (83% versus 17%, p = 0.0001). However, there were no differences in the extent, severity, or distribution of coronary stenoses in patients with silent or symptomatic ischemia. Our major observation was that the extent of quantified SPECT perfusion defects was nearly identical in patients with (20.9 +/- 15.9%) and without (20.5 +/- 15.6%) exertional chest pain. The sensitivity for detecting the presence of CAD was significantly improved with quantitative SPECT compared with stress electrocardiography (87% versus 65%, p = 0.0001). Although scintigraphic and electrocardiographic evidence of exercise-induced ischemia were comparable in patients with chest pain (67% versus 73%, respectively; p = NS), SPECT was superior to stress electrocardiography for detecting silent myocardial ischemia. The majority of patients in this study with CAD who developed ischemia during exercise testing were asymptomatic, although they exhibited an angiographic profile and extent of abnormally perfused myocardium similar to those of patients with symptomatic ischemia.

  1. Estimation of sensitivity and specificity of brain magnetic resonance imaging and single photon emission computed tomography in the diagnosis of olfactory dysfunction after head traumas.

    PubMed

    Atighechi, Saeid; Zolfaghari, Aliasghar; Baradaranfar, Mohammadhossein; Dadgarnia, Mohammadhossein

    2013-01-01

    Olfactory dysfunction has an incidence of 5-10% after head injury. Several objective and subjective tests had been proposed. Recent studies showed that brain single photon emission computed tomography (SPECT) and brain magnetic resonance imaging (MRI) have good diagnostic value in this era in which the most common sites of involvement were olfactory bulb and olfactory nerve in MRI and frontal lobe in SPECT. This study aimed to estimate the sensitivity and specificity of brain MRI and brain SPECT in the diagnosis of traumatic hyposmia and anosmia. From February 2009 to March 2011, 63 patients with head injury and smell complaint were selected for this study. Using an identification test and a threshold smell test, 28 were anosmic and 27 had hyposmia and the remaining 8 were normosmic. All of them underwent brain MRI and SPECT. The sensitivity of SPECT was 81.5 and 85.7% in hyposmia and anosmia, respectively. Its specificity was 87.5% in anosmia and 87.7% in anosmia. MRI sensitivity was 66.7% in hyposmia but 82.1% in anosmia. Its specificity was 85.7% in anosmia and 87.7% in anosmia. If MRI and SPECT were considered together, the sensitivity was 92.3% in hyposmia and 92% in anosmia, but the specificity was 87% in both cases. According to our study, both brain MRI and SPECT have high sensitivity and specificity in the diagnosis of traumatic anosmia, although brain SPECT is slightly superior to MRI. If the two techniques are applied together, the accuracy will be increased.

  2. Quantifying regional cerebral blood flow by N-isopropyl-P-[I-123]iodoamphetamine (IMP) using a ring type single-photon emission computed tomography system

    SciTech Connect

    Takahashi, N.; Odano, I.; Ohkubo, M.

    1994-05-01

    We developed a more accurate quantitative measurement of regional cerebral blood flow (rCBF) with the microsphere model using N-isopropyl-p-[I-123] iodoamphetamine (IMP) and a ring type single photon emission computed tomography (SPECT) system. SPECT studies were performed in 17 patients with brain diseases. A dose of 222 MBq (6 mCi) of [I-123]IMP was injected i.v., at the same time a 5 min period of arterial blood withdrawal was begun. SPECT data were acquired from 25 min to 60 min after tracer injection. For obtaining the brain activity concentration at 5 min after IMP injection, total brain counts collections and one minute period short time SPECT studies were performed at 5, 20, and 60 min. Measurement of the values of rCBF was calculated using short time SPECT images at 5 min (rCBF), static SPECT images corrected with total cerebral counts (rCBF{sub Ct}.) and those corrected with reconstructed counts on short time SPECT images (rCBF{sub Cb}). There was a good relationship (r=0.69) between rCBF and rCBF{sub Ct}, however, rCBF{sub Ct} tends to be underestimated in high flow areas and overestimated in low flow areas. There was better relationship between rCBF and rCBF{sub Cb}(r=0.92). The overestimation and underestimation shown in rCBF{sub Ct} was considered to be due to the correction of reconstructed counts using a total cerebral time activity curve, because of the kinetic behavior of [I-123]IMP was different in each region. We concluded that more accurate rCBF values could be obtained using the regional time activity curves.

  3. A new method for measuring dynamic change of tracer distribution using dynamic single photon emission tomography with a slip-ring rotational gamma camera.

    PubMed

    Miyazaki, Y; Hashimoto, M; Kinuya, S; Murata, Y; Inoue, H; Shiozaki, J; Takimoto, M; Yoshioka, K; Nakajima, K; Taki, J

    2002-11-01

    The clinical applicability of dynamic single photon emission tomograpy (SPET) using a dual-head gamma camera equipped with a slip-ring rotational mechanism, referred to as serial SPET, was examined in the present investigation. Serial SPET enables the production of tomographic images for any arbitrary time frame from an arbitrary range of data to 360 degrees. In a pre-clinical evaluation, a correlation between radioactivity concentration and serial SPET counts was evaluated in a phantom with continuous changes in 99mTc concentration. A differential value was obtained from each pair of SPET images; moreover, moving average approximation processing was investigated with respect to the elimination of noise in the data. In 11 and one patient presenting with cerebrovascular disease and meningioma, respectively, changes in SPET counts were evaluated when 99mTc ethyl cysteinate dimer (99mTc-ECD) was continuously administered at a constant rate in the resting state. Furthermore, in six of 11 subjects with cerebrovascular disease, changes occurring in SPET counts were examined by using acetazolamide loading while continuously administering 99mTc-ECD at a constant rate. Consequently, serial SPET enabled the evaluation of changes in radioactivity concentration over time in both the phantom and preliminary clinical studies. Data analysis by differential processing utilizing moving average approximation processing enabled the detection of minor changes in radioactivity concentration. An increase of 15.1+/-5.4% was observed in SPET counts of the unaffected cerebral hemisphere with acetazolamide loading. The response of the affected hemisphere was less prominent. These findings suggest that serial SPET would be an effective technique for the pharmacokinetic analysis of radiopharmaceuticals.

  4. Risk of node metastasis of sentinel lymph nodes detected in level II/III of the axilla by single-photon emission computed tomography/computed tomography

    PubMed Central

    SHIMA, HIROAKI; KUTOMI, GORO; SATOMI, FUKINO; MAEDA, HIDEKI; TAKAMARU, TOMOKO; KAMESHIMA, HIDEKAZU; OMURA, TOSEI; MORI, MITSURU; HATAKENAKA, MASAMITSU; HASEGAWA, TADASHI; HIRATA, KOICHI

    2014-01-01

    In breast cancer, single-photon emission computed tomography/computed tomography (SPECT/CT) shows the exact anatomical location of sentinel nodes (SN). SPECT/CT mainly exposes axilla and partly exposes atypical sites of extra-axillary lymphatic drainage. The mechanism of how the atypical hot nodes are involved in lymphatic metastasis was retrospectively investigated in the present study, particularly at the level II/III region. SPECT/CT was performed in 92 clinical stage 0-IIA breast cancer patients. Sentinel lymph nodes are depicted as hot nodes in SPECT/CT. Patients were divided into two groups: With or without hot node in level II/III on SPECT/CT. The existence of metastasis in level II/III was investigated and the risk factors were identified. A total of 12 patients were sentinel lymph node biopsy metastasis positive and axillary lymph node dissection (ALND) was performed. These patients were divided into two groups: With and without SN in level II/III, and nodes in level II/III were pathologically proven. In 11 of the 92 patients, hot nodes were detected in level II/III. There was a significant difference in node metastasis depending on whether there were hot nodes in level II/III (P=0.0319). Multivariate analysis indicated that the hot nodes in level II/III and lymphatic invasion were independent factors associated with node metastasis. There were 12 SN-positive patients followed by ALND. In four of the 12 patients, hot nodes were observed in level II/III. Two of the four patients with hot nodes depicted by SPECT/CT and metastatic nodes were pathologically evident in the same lesion. Therefore, the present study indicated that the hot node in level II/III as depicted by SPECT/CT may be a risk of SN metastasis, including deeper nodes. PMID:25289038

  5. Differential patterns of dopamine transporter loss in the basal ganglia of progressive supranuclear palsy and Parkinson's disease: analysis with [(123)I]IPT single photon emission computed tomography.

    PubMed

    Im, Joo-Hyuk; Chung, Sun J; Kim, Jae-Seung; Lee, Myoung C

    2006-05-15

    We evaluated the patterns of dopamine transporter loss in the striatum of ten controls, twenty patients with Parkinson's disease (PD), and nine with progressive supranuclear palsy (PSP) using (123)I-IPT single photon emission tomography (SPECT). Four ROIs in the striatum correspond to the head of caudate nucleus (ROI 1), a transitional region between head of caudate and putamen (ROI 2), anterior putamen (ROI 3), and posterior putamen (ROI 4). A striatal ratio of specific to nondisplaceable uptake (V3'') was calculated normalizing the activity of the ROIs to that of occipital cortex. V3'' values were significantly reduced in all ROIs of PD and PSP patients, compared with controls (p=0.001). V3'' value in ROI 2 was significantly lower in PSP group, compared with PD group (p=0.02). The percent reductions of striatal uptake in ROI 1, ROI 2, ROI 3 and ROI 4 were 56%, 53%, 64% and 78% in PD patients, whereas 75%, 72%, 75% and 77% in PSP patients, respectively. The reduction patterns of uptake were significantly different between PD and PSP groups (p=0.001). In PD patients, the percent reductions of (123)I-IPT uptake were significantly greater in ROI 3 and 4 compared with ROI 1 or 2, whereas those were similar in all ROIs of PSP patients. In addition, PD patients showed a significantly higher posterior putamen/caudate ratio of reduced (123)I-IPT uptake than the anterior putamen/caudate ratio (p=0.005). Our results implicate that (123)I-IPT SPECT is a relatively simple and reliable technique that may be useful in differentiating PD from PSP.

  6. Regadenoson-stress myocardial CT perfusion and single-photon emission CT: rationale, design, and acquisition methods of a prospective, multicenter, multivendor comparison.

    PubMed

    Cury, Ricardo C; Kitt, Therese M; Feaheny, Kathleen; Akin, Jamie; George, Richard T

    2014-01-01

    Pharmacologic stress myocardial CT perfusion (CTP) has been reported to be a viable imaging modality for detection of myocardial ischemia compared with single-photon emission CT (SPECT) in several single-center studies. However, regadenoson-stress CTP has not previously been compared with SPECT in a multicenter, multivendor study. The rationale and design of a phase 2, randomized, cross-over study of regadenoson-stress myocardial perfusion imaging by CTP compared with SPECT are described herein. The study will be conducted at approximately 25 sites by using 6 different CT scanner models, including 64-, 128-, 256-, and 320-slice systems. Subjects with known/suspected coronary artery disease will be randomly assigned to 1 of 2 imaging procedure sequences; rest and regadenoson-stress SPECT on day 1, then regadenoson-stress CTP and rest CTP/coronary CT angiography (same acquisition) on day 2; or regadenoson-stress CTP and rest CTP/CT angiography on day 1, then rest and regadenoson-stress SPECT on day 2. The prespecified primary analysis examines the agreement rate between CTP and SPECT for detecting or excluding ischemia (≥2 or 0-1 reversible defects, respectively), as assessed by 3 independent blinded readers for each modality. Non-inferiority will be indicated if the lower boundary of the 95% CI for the agreement rate is within 0.15 of 0.78 (the observed agreement rate in the regadenoson pivotal trials). The protocol described herein will support the first evaluation of regadenoson-stress CTP by using multiple scanner types compared with SPECT.

  7. 99Tcm-MIBI single photon emission tomography (SPET) for detecting myocardial ischaemia and necrosis in patients with significant coronary artery disease.

    PubMed

    Sciammarella, M G; Fragasso, G; Gerundini, P; Maffioli, L; Cappelletti, A; Margonato, A; Savi, A; Chierchia, S

    1992-12-01

    The ability of 99Tcm-methoxyisobutylisonitrile (MIBI) single photon emission tomography (SPET) to detect myocardial ischaemia and necrosis was assessed in 56 patients (45 male, 11 female, aged 55 +/- 5 years), with clinically recognized ischaemic heart disease (IHD). All underwent coronary angiography (CA) and left ventriculography (LV). SPET images were obtained at rest and at peak exercise (Modified Bruce) 90 min after injection of 99Tcm-MIBI (650-850 MBq). Data were acquired in 30 min over 180 degrees (from 45 degrees RAO to 45 degrees LPO) with no correction for attenuation, using a 64 x 64 matrix. The presence of persistent (P) or reversible (R) perfusion defects (PD) was then correlated to the resting and exercise ECG and to the results of CA and LV. Of the 56 patients, 34 had reversible underperfusion (RPD), 46 persistent underperfusion (PPD) and 31 had both. The occurrence of RPD correlated well with the occurrence of exercise-induced ST segment depression and/or angina (27 patients of 34 patients, 79%) and with the presence of significant coronary artery disease (CAD) (33 of 44, 73%). In 45 of 46 patients (98%) PPD corresponded to akinetic or severely hypokinetic segments (LV) usually explored by ECG leads exhibiting diagnostic Q waves (42 of 46 patients, 91%). The scan was normal both at rest and after stress in four of 11 patients with no CAD, and in two of 45 patients with CAD. Finally, an abnormal resting scan was seen in seven of 11 patients with normal coronary arteries, of whom six had regional wall motion abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Striatal Dopamine Transporter Modulation After Rotigotine: Results From a Pilot Single-Photon Emission Computed Tomography Study in a Group of Early Stage Parkinson Disease Patients.

    PubMed

    Rossi, Carlo; Genovesi, Dario; Marzullo, Paolo; Giorgetti, Assuero; Filidei, Elena; Corsini, Giovanni Umberto; Bonuccelli, Ubaldo; Ceravolo, Roberto

    Several in vitro data have reported negative interference by dopamine-agonists on the expression of dopamine transporter (DAT), whereas the majority of imaging studies have shown that neither L-dopa nor dopamine-agonists interfere with DAT availability. As yet, there are no in vivo studies on DAT expression after treatment with rotigotine. We evaluated presynaptic nigrostriatal function in 8 patients with de novo Parkinson disease (age, 59 ± 6.2 years; male/female sex, 5/3) using 123-I- N-ω-fluoropropyl-2-β-carbomethoxy-3-β-(4-iodophenyl)nortropane (FP-CIT) single-photon emission computed tomography before and after 3 months of treatment with rotigotine (mean dose, 7.75 ± 1.98 mg). For data analysis, specific (left and right caudate, left and right putamen) to nonspecific (occipital cortex) binding ratios, putamen-to-caudate ratios, and asymmetry indices were calculated. After rotigotine, motor symptoms improved in all patients (Unified Parkinson Disease Rating Scale III mean score, 11.88 ± 2.59 vs 7.63 ± 1.92 on therapy; P = 0.0022). Striatal FP-CIT levels showed a significant improvement in every patient at the follow-up scan. Comparisons between before and after treatment in the whole group revealed a significant improvement in FP-CIT uptake in both caudate and putamen (P < 0.001 in each nucleus). Putamen-to-caudate ratio and asymmetry indices did not show any significant difference before and after treatment. Although the study population was small, we found DAT overexpression after chronic treatment with rotigotine, presumably related to its pharmacological profile. The DAT upregulation by rotigotine in an opposite direction with respect to early Parkinson disease compensatory mechanisms might reduce the risk of dyskinesia, but it could imply less motor benefit because of less stimulation by the dopamine itself on dopaminergic receptors.

  9. Potential advantage of preoperative three-dimensional mapping of sentinel nodes in breast cancer by a hybrid single photon emission CT (SPECT)/CT system.

    PubMed

    Ibusuki, Mutsuko; Yamamoto, Yutaka; Kawasoe, Teru; Shiraishi, Shinya; Tomiguchi, Seiji; Yamashita, Yasuyuki; Honda, Yumi; Iyama, Kenichi; Iwase, Hirotaka

    2010-06-01

    This study aims to assess the role of three-dimensional single-photon emission computed tomography (3D-SPECT/CT) in sentinel node (SN) identification, and to analyze the impact of such information on estimating metastases to SNs. Nodal status is a key factor for breast cancer. SN biopsy has been established as the alternative to routine axillary dissection these days. We investigated both the anatomical location of SNs demonstrated by our 3D-SPECT/CT system and the correlation to SN positivity. Two hundred and twenty-three clinically node-negative patients underwent SN biopsy. All of the axillary structures, including SNs, were visualized by a SPECT/CT combined system after subcutaneous injection of (99m)Tc-phytate. By plotting the visualized SNs, the most frequent SN location 'Pedestal area (PA)' was designated. SPECT/CT detected (99m)Tc uptake in 217 cases (97.3%). 3D-SPECT/CT images visualized the accurate location of SNs in each case. In patients whose SNs were histopathologically negative (SN-), 228 (98.3%) SNs were found in the PA, and 4 (1.7%) were in other zones. In those with histopathologically positive SNs (SN+), 65 (78.3%) SNs were in the PA and 18 (21.7%) were outside it. The difference in SN distribution (i.e., in or out of the PA) between SN+ and SN- patients was statistically significant (p<0.001, chi-square test). SN biopsy navigated by 3D-SPECT/CT can clarify the preoperative anatomical localization of SNs in patients with breast cancer. Atypical distribution of SNs out of the PA may suggest SN positivity, reflecting failure of the lymphatic drainage systems.

  10. Effects of hemoglobin level on myocardial washout rate of thallium-201 in patients with normal myocardial perfusion assessed by single-photon emission computed tomography.

    PubMed

    Kurisu, Satoshi; Sumimoto, Yoji; Ikenaga, Hiroki; Watanabe, Noriaki; Ishibashi, Ken; Dohi, Yoshihiro; Fukuda, Yukihiro; Kihara, Yasuki

    2017-04-05

    Myocardial perfusion single-photon emission computed tomography (SPECT) is often performed even in patients with suspected coronary artery disease complicated by anemia. We assessed the effects of hemoglobin level on myocardial washout rate of Thallium-201 (Tl-201) in patients with normal myocardial perfusion assessed by SPECT. The study population consisted of 231 patients with summed stress score of zero on SPECT. The mean myocardial washout rate of Tl-201 in the left ventricle was calculated from the stress and the redistribution Bull's eye map. Hematological test was performed within 2 weeks before gated SPECT. There were 135 male and 96 female patients with a mean age of 72.6 ± 9.0 years. The mean hemoglobin was 12.9 ± 1.9 mg/dl; the median was 13.2 mg/dl and the range was 8.0-16.5 mg/dl. There was a significant inverse correlation between hemoglobin level and myocardial washout rate of Tl-201 (r = -0.45, p < 0.001). Univariate linear regression analysis showed that age, female, body mass index, serum creatinine, hemoglobin, end-diastolic volume, and ejection fraction were associated with myocardial washout rate of Tl-201. Multivariate analysis showed that only hemoglobin was the independent predictor of myocardial washout rate of Tl-201 (β = -0.35, p < 0.001). Our data suggested that anemia was a major determinant of increased myocardial washout rate of Tl-201 in patients with normal myocardial perfusion on SPECT.

  11. Assessment of coronary artery disease using single-photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Nguyen, T.; Beer, S.G.; Cave, V.; Ogilby, J.D.; Untereker, W.; Segal, B.L. )

    1991-06-01

    Thallium-201 myocardial imaging during dipyridamole-induced coronary hyperemia has been an accepted method for diagnosing coronary artery disease (CAD) and risk stratification. Adenosine is a powerful short-acting coronary vasodilator. Initial results of thallium imaging during adenosine infusion have been encouraging. In 132 patients with CAD and in 16 patients with normal coronary angiograms, adenosine was given intravenously at a dose of 0.14 mg/kg/min for 6 minutes and thallium-201 was injected at 3 minutes. The thallium images using single-photon emission computed tomography were abnormal in 47 of the 54 patients (87%) with 1-vessel, in 34 of 37 patients (92%) with 2-vessel and in 40 of 41 patients (98%) with 3-vessel CAD. The sensitivity was 92% in the 132 patients with CAD (95% confidence intervals, 86 to 96%). In patients with normal coronary angiograms, 14 of 16 patients had normal thallium images (specificity, 88%; 95% confidence intervals, 59 to 100%). The results were very similar when subgroups of patients were analyzed: those without prior myocardial infarction, elderly patients and women. The nature of the perfusion defects (fixed or reversible) was assessed in relation to whether the 4-hour delayed images were obtained with or without the reinjection technique. In patients who underwent conventional delayed imaging, there were more fixed perfusion defects than in patients with reinjection delayed imaging (16 vs 0%, p less than 0.0001). The adverse effects were mild, transient and well tolerated. Thus, adenosine thallium tomographic imaging provides a high degree of accuracy in the diagnosis of CAD. The use of the reinjection technique enhances the ability to detect reversible defects.

  12. Thallium-201 single-photon emission computed tomography: quantitative assessment of left ventricular perfusion and structural change in patients with chronic aortic regurgitation.

    PubMed

    Yasuda, Harumasa; Taniguchi, Kazuhiro; Takahashi, Toshiki; Sawa, Yoshiki; Matuda, Hikaru

    2005-12-01

    Previously, perfusion defect in the left ventricle was detected by thallium-201 (201T1) single-photon emission computed tomography (SPECT) in aortic regurgitation (AR). The significance of 201T1 SPECT, however, has not been clarified. Limited information is available regarding the relationship between functional characteristics and scintigraphic findings. The purpose of this study was to elucidate the role of exercise 201T1 SPECT in assessing myocardial perfusion or structural change in chronic AR. We examined the correlation between 201T1 scintigraphic findings and left ventricular (LV) function parameters in 11 patients. Defect volume ratio (DVR) in exercise 201T1 SPECT was used as a parameter of the range of abnormal thallium distribution. Left ventricular parameters were obtained by right and retrograde left cardiac catheterizations. The relationship between DVR and the parameters was analyzed. The DVR ranged from 1.0 to 28.3% (average 12.1 + 8.5 %). There was a significant correlation (r = 0.77, p < 0.05) between DVR and end-diastolic volume index (EDVI), a definite correlation (r = 0.66, p < 0.01) between DVR and end-systolic volume index (ESVI), and a good correlation (r = -0.77, p <0.05) between DVR and end-systolic wall stress (ESS)/ ESVI; however, no such correlation was found between DVR and ejection fraction. All patients showed abnormal defects in 201T1 accumulation scattered across the entire ventricle. A strong correlation between DVR and ESS/ESVI, an index of myocardial contractility, was a major finding of this study, suggesting a significant association between abnormal myocardial perfusion or structural alteration and reduction in myocardial contractility in chronic AR.

  13. Motion-frozen Imaging by Gated Myocardial Perfusion Single Photon Emission Computed Tomography Using Multi-focus Fan Beam Collimator in Thallium-201 Study.

    PubMed

    Takahashi, Kaito; Takeuchi, Takashi; Hosokai, Yoshiyuki; Odagiri, Hayato; Saito, Haruo

    This study aimed to evaluate the statistical noise of motion-frozen (MF) image generated by gated myocardial perfusion single photon emission computed tomography (SPECT) imaging using IQ · SPECT and to determine the optimal acquisition and reconstruction parameters for MF image using IQ · SPECT. A movement cardiac phantom and static cardiac phantom were used to acquire the MF images. The acquisition times used were different in 8 and 16 frames per R-R interval, and varying reconstruction parameters (subset and iteration) were used. We determined the %CV value, contrast, and normalized mean square error (NMSE) to evaluate the image quality. The %CV value for a MF image with IQ · SPECT was lower than that for a conventional non-gated myocardial perfusion SPECT (MPS) image with low energy high resolution (LEHR). With regard to the acquisition parameters, the contrast did not change when the acquisition time was increased in 8 and 16 frames per R-R interval. NMSE converged in 56 beats/view in 8 frames per R-R interval. With regard to the reconstruction parameters, the contrast and the %CV value of the anterior and septal wall converged in update 40. The minimum NMSE in subsets 1, 2, and 3 were almost similar. Uniformity in the MF image with IQ · SPECT was higher than that in the conventional image. The results of this MF image with IQ · SPECT study suggest that the optimal acquisition parameter should be 56 beats/view in 8 frames per R-R interval, and the optimal reconstruction parameters should be subset 3 and iteration 14.

  14. Effects of chronic kidney disease on myocardial washout rate of thallium-201 in patients with normal myocardial perfusion on single photon emission computed tomography.

    PubMed

    Kurisu, Satoshi; Sumimoto, Yoji; Ikenaga, Hiroki; Ishibashi, Ken; Fukuda, Yukihiro; Kihara, Yasuki

    2017-09-06

    Myocardial perfusion single photon emission computed tomography (SPECT) is often performed even in patients with chronic kidney disease (CKD). We assessed the effects of CKD on myocardial washout rate (WR) of thallium (Tl)-201 in patients with normal myocardial perfusion on SPECT. Two hundred and fifty-six patients with normal myocardial perfusion were enrolled in this study. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2). Patients with eGFR ≥ 60 ml/min/1.73 m(2) were assigned to a control group. The mean myocardial WR of Tl-201 was calculated from the stress and the redistribution Bull's eye maps. With progressive CKD stages, systolic blood pressure and incindence of hypertension were increased. All patients in CKD stage 5 group were being treated with hemodialysis. Myocardial WR of Tl-201 was significantly higher in all of the CKD groups than control group. With progressive CKD stages, myocardial WR of Tl-201 was increased (stage 3, 52.2 ± 9.2%; stage 4, 55.5 ± 8.1%; and stage 5, 58.9 ± 5.6%). Multivariate analysis showed that hemoglobin (β = -0.24, p < 0.001) and eGFR (β = -0.24, p = 0.002) were the major determinants of myocardial WR of Tl-201, but hemodialysis was not. Our data suggest that CKD is associated with increased myocardial WR of Tl-201 in patients with normal perfusion on SPECT.

  15. Single photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia: Correlation with coronary arteriography, exercise thallium imaging and two-dimensional echocardiography

    SciTech Connect

    Nguyen, T.; Heo, J.; Ogilby, J.D.; Iskandrian, A.S. )

    1990-11-01

    The feasibility, safety and diagnostic accuracy of single photon emission computed tomography (SPECT) with thallium-201 imaging during adenosine-induced coronary hyperemia were evaluated in 53 patients with and 7 without coronary artery disease proved by coronary angiography. Adenosine was infused intravenously at a dose of 0.14 mg/kg body weight per min for 6 min and thallium was injected at 3 min. Adenosine caused an increase in heart rate (68 +/- 12 at baseline versus 87 +/- 18 beats/min at peak effect, p less than 0.0001) but no change in blood pressure. The sensitivity and specificity were 92% (95% confidence intervals 81% to 98%) and 100% (95% confidence intervals 59% to 100%), respectively; 20 (61%) of 33 patients with multivessel coronary artery disease were also correctly identified. In 30 patients, the predictive accuracy of adenosine thallium imaging was slightly higher than that of exercise SPECT thallium imaging (90% versus 80%, p = NS) (95% confidence intervals 72% to 97% and 61% to 92%, respectively). In 25 patients, two-dimensional echocardiography during adenosine infusion disclosed a new wall motion abnormality in 2 (10%) of 20 patients with coronary artery disease; 80% of these patients had reversible thallium defects (p less than 0.001). Side effects were mild and transient; aminophylline was used in only three patients. Thus, adenosine SPECT thallium imaging provides a high degree of accuracy in the diagnosis of coronary artery disease. The results are comparable with those of exercise SPECT thallium imaging. Most reversible defects in the adenosine study are not associated with any transient wall motion abnormality.

  16. The variable extent of jeopardized myocardium in patients with single vessel coronary artery disease: Quantification by thallium-201 single photon emission computed tomography

    SciTech Connect

    Mahmarian, J.J.; Pratt, C.M.; Boyce, T.M.; Verani, M.S. )

    1991-02-01

    To assess the extent of jeopardized myocardium in patients with single vessel coronary artery disease of variable severity and location, quantitative exercise thallium-201 single photon emission computed tomography was performed in 158 consecutive patients with angiographically proved single vessel coronary artery disease. The extent of abnormal left ventricular perfusion was quantified from computer-generated polar maps of three-dimensional myocardial radioactivity. Patients with only a moderate (51% to 69%) stenosis tended to have a small perfusion defect irrespective of the coronary artery involved. Whereas a perfusion defect measuring greater than or equal to 10% of the left ventricle was found in 78% of patients with no prior infarction and severe (greater than or equal to 70%) stenosis, this was observed in only 24% of patients with moderate stenosis. Perfusion defect size increased with increasing severity of stenosis for the entire group without infarction and for those with left anterior descending, right and circumflex coronary artery stenosis. However, the correlation between stenosis severity and perfusion defect size was at best only modest (r = 0.38, p = 0.0001). The left anterior descending artery was shown to be the most important of the three coronary arteries for providing left ventricular perfusion. Proximal stenosis of this artery produced a perfusion defect approximately twice as large as that found in patients with a proximal right or circumflex artery stenosis. However, marked heterogeneity in perfusion defect size existed among all three vessels despite comparable stenosis severity. This was most apparent for the left anterior descending coronary artery, where mid vessel stenosis commonly produced a perfusion defect similar in size to that found in proximally stenosed vessels.

  17. Interactions of regional respiratory mechanics and pulmonary ventilatory impairment in pulmonary emphysema: assessment with dynamic MRI and xenon-133 single-photon emission CT.

    PubMed

    Suga, K; Tsukuda, T; Awaya, H; Matsunaga, N; Sugi, K; Esato, K

    2000-06-01

    Dynamic MRI and (133)Xe single-photon emission CT (SPECT) were used to directly evaluate the interaction of regional respiratory mechanics and lung ventilatory function in pulmonary emphysema. Respiratory diaphragmatic and chest wall (D/CW) motions were analyzed by sequential MRI of fast-gradient echo pulse sequences during two to three respiratory cycles in 28 patients with pulmonary emphysema, including 9 patients undergoing lung volume reduction surgery (LVRS). The extent of air trapping in the regional lung was quantified by the (133)Xe retention index (RI) on three-dimensional (133)Xe SPECT displays. By contrast to healthy subjects (n = 6) with regular, synchronous D/CW motions, pulmonary emphysema patients showed reduced, irregular, or asynchronous motions in the hemithorax or location with greater (133)Xe retention, with significant decreases in the maximal amplitude of D/CW motions (MADM and MACWM; p < 0.0001 and p < 0.05, respectively). The removal of (133)Xe retention sites by LVRS effectively and regionally improved D/CW motions in nine patients, with significant increases in MADM and MACWM (p < 0.01 and p < 0.001, respectively). In a total of 40 studies of the 28 patients including post-LVRS studies, normalized MADM and MACWM correlated with percent predicted FEV(1) (r = 0.881, p < 0.0001; and r = 0.906, p < 0.0001, respectively), and also with (133)Xe RI in each hemithorax (r = -0.871, p < 0 0.0001; and r = -0.901, p < 0 0.0001, respectively.) This direct comparison of regional respiratory mechanics with lung ventilation demonstrated a close interaction between these impairments in pulmonary emphysema. The present techniques provide additional sensitivity for evaluating pathophysiologic compromises in pulmonary emphysema, and may also be useful for selecting resection targets for LVRS and for monitoring the effects.

  18. Gated myocardial perfusion single photon emission computed tomography in the clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial, Veterans Administration Cooperative study no. 424.

    PubMed

    Shaw, Leslee J; Heller, Gary V; Casperson, Paul; Miranda-Peats, Romalisa; Slomka, Piotr; Friedman, John; Hayes, Sean W; Schwartz, Ronald; Weintraub, William S; Maron, David J; Dada, Marcin; King, Spencer; Teo, Koon; Hartigan, Pamela; Boden, William E; O'Rourke, Robert A; Berman, Daniel S

    2006-09-01

    Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial. The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization patients. Substudy 2 (n = 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization in reducing patients' ischemic burdens. The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology. We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based management of patients with stable coronary disease.

  19. Normal limits for left ventricular ejection fraction and volumes determined by gated single photon emission computed tomography--a comparison between two quantification methods.

    PubMed

    Lomsky, Milan; Johansson, Lena; Gjertsson, Peter; Björk, Jonas; Edenbrandt, Lars

    2008-05-01

    To compare gender-related normal limits for left ventricular (LV) ejection fraction (EF), end-diastolic and end-systolic volumes (EDV and ESV), obtained using two myocardial perfusion-gated single photon emission computed tomography (SPECT) quantification methods. A total of 185 patients were retrospectively selected from a consecutive series of patients examined for coronary artery disease (CAD) or for management of known CAD. Patients were included in the study group if they had normal or probably normal results with stress and rest perfusion imaging and if the combined interpretation of perfusion studies and gated rest studies showed no signs or suspicion of myocardial infarction. The gated SPECT studies were performed using a 2-day stress/gated rest Tc-99m sestamibi protocol. All patient studies were processed using CAFU and quantitative-gated SPECT (QGS), the two software packages for quantification of gated SPECT images. The lower normal limits for EF were higher for CAFU compared with QGS for both women (59% versus 53%) and men (54% versus 47%). The upper normal limits for EDV were also higher for CAFU compared with QGS for both women (133 versus 107 ml) and men (182 versus 161 ml). The differences between the software packages were small for ESV (women 44 versus 44 ml; men 69 versus 74 ml). Gender-specific normal limits need to be applied for LV EF and volumes determined by gated SPECT. Separate criteria for abnormal LV EF and EDV need to be used for women and men depending on the software package used.

  20. Echocardiography versus (201)Tl semi-quantitative gated single photon emission tomography for the evaluation of cardiac disease associated with late stage Duchenne muscular dystrophy.

    PubMed

    Fujita, Atsushi; Arahata, Hajime; Sugawara, Miwa; Watanabe, Akihiro; Kawano, Yuji; Sasagasako, Naokazu; Fujii, Naoki

    2016-01-01

    In Duchenne muscular dystrophy (DMD) patients cardiac abnormalities are often detected. In adult DMD patients cardiac disease (CD) is a cause of death which increases by age and is related to respiratory dysfunction. Studies have demonstrated that CD in early DMD can be detected by echocardiography (EC) or semi-quantitative gated single photon emission tomography ((201)Tl SQGS), and the accuracy of these two tests is similar. As the disease advances, evaluation of CD by EC becomes difficult due to thoracic deformity and scoliosis. We compared (201)Tl SQGS and EC in the evaluation of cardiac function in late stage DMD, based on the ejection fraction (EF) value calculated by both tests. Twenty-three males with late stage DMD, 12 to 35 years of age (22.2±7.5), were studied by (201)Tl SQGS and EC. The mean EF value by (201)Tl SQGS was 60.8%±14.1%, which differed from that obtained by EC (52.7%±9.8%, P=0.003). Eleven patients less than 20 years old did not demonstrate a significant difference between the two tests (P=0.06), however, 12 patients over 20 years of age had significantly different results between tests (P=0.002). Although our patients were few we indicated that in DMD patients, aged older than 20 years, at an advanced stage of the disease, the EF values calculated by EC were lower than those by (201)Tl SQGS possibly due to thoracic deformity.

  1. Assessment of Hemodynamic Compromise Using Computed Tomography Perfusion in Combination with (123)I-IMP Single-Photon Emission Computed Tomography without Acetazolamide Challenge Test.

    PubMed

    Hashimoto, Atsumu; Mikami, Takeshi; Komatsu, Katsuya; Noshiro, Shouhei; Hirano, Tohru; Wanibuchi, Masahiko; Mikuni, Nobuhiro

    2017-03-01

    The acetazolamide challenge test in conjunction with (123)I-IMP single-photon emission computed tomography (SPECT) is a known method of assessing cerebrovascular reserve capacity. In this study, we investigated whether CT perfusion in combination with resting state (123)I-IMP SPECT could be used instead of the acetazolamide challenge test to evaluate hemodynamic compromise in patients with atherosclerotic occlusive disease. Twenty consecutive patients with unilateral internal carotid artery or middle cerebral artery steno-occlusive disease were enrolled. (123)I-IMP SPECT was performed with and without the acetazolamide challenge test, and with CT perfusion. Cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) obtained by CT perfusion were compared with CBF and cerebrovascular reactivity (CVR) obtained by (123)I-IMP SPECT. The asymmetry ratio of MTT as measured by CT perfusion showed a strong correlation with the CVR to acetazolamide as measured by (123)I-IMP SPECT (ρ = -.780, P <.001). Based on the CBF obtained through (123)I-IMP SPECT and the MTT obtained through CT perfusion, hemodynamic compromise was detected with high sensitivity (1.000) and specificity (.929), and a cutoff value of 30% was found to be suitable for the asymmetry ratio of MTT. MTT prolongation was significantly improved after revascularization surgery in hemodynamic compromise (P = .028). MTT as measured by CT perfusion in combination with CBF as measured by resting state (123)I-IMP SPECT may be useful for evaluating hemodynamic compromise as an alternative to the acetazolamide challenge test. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. Myocardial perfusion gated single-photon emission computed tomography in patients with left bundle branch block: comparison between the end-diastolic images and the ungated images.

    PubMed

    Edet-Sanson, Agathe; Hitzel, Anne; Guernou, Mohamed; Véra, Pierre; Manrique, Alain

    2009-01-01

    Septal perfusion abnormalities are frequently observed in patients with left bundle branch block (LBBB). The aim of this study was to compare myocardial perfusion imaging obtained from ungated and diastolic thallium gated single-photon emission computed tomography (SPECT) images in patients with LBBB. Stress/rest SPECT was performed in 70 patients with LBBB [38 with coronary artery disease (CAD) (G1), 32 without (G2)] and 19 control participants (G3). Diastolic images were obtained as the sum of four diastolic bins. Perfusion was assessed by summed stress, rest, and difference scores for both diastolic and ungated images. In G1, there was no difference between diastolic and ungated perfusion scores. In G2, summed stress score and summed rest score were increased in diastolic versus ungated imaging, and perfusion defect extent was increased on diastolic versus ungated images at stress (diastole: 6.2 +/- 9.9% vs. ungated: 5.1 +/- 9.70/%, P = 0.01) and rest (diastole: 4.3 +/- 9.3% vs. ungated: 2.8 +/- 9.50%, P = 0.0014), with an increased extent of reversible defect (diastole: 3.4 4.7% vs. ungated: 2.3 3.7%, P = 0.01). In G2, diastolic images failed to correct septal perfusion abnormalities. The number of normal SPECT did not increase with diastolic versus ungated imaging (24 and 180% in G1, 66 and 53% in G2, respectively). Otherwise, a significant association between left ventricular dysfunction and CAD was found, stress ejection fraction being decreased in 20 patients (53%) in G1 and seven patients (22%) in G2 (CHI2 = 6.93, P < 0.01). In patients with LBBB, diastolic imaging did not provide additional information to ungated perfusion imaging, but left ventricular dysfunction was associated with CAD.

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

    PubMed

    Katayama, Takuji; Ogata, Nobuhiko; Tsuruya, Yoshio

    2008-05-01

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

  4. Evaluation of Silent Myocardial Ischemia with Single-Photon Emission Computed Tomography/Computed Tomography in Asymptomatic Subjects with Diabetes and Pre-Diabetes

    PubMed Central

    Özdemir, Elif; Burçak Polat, Şefika; Yıldırım, Nilüfer; Türkölmez, Şeyda; Ersoy, Reyhan; Durmaz, Tahir; Keleş, Telat; Bozkurt, Engin; Çakır, Bekir

    2016-01-01

    Objective: The aim of this study was to disclose the prevalence of myocardial ischemia, as detected by adenosine stress myocardial perfusion imaging (MPI) with hybrid single-photon emission computed tomography/computed tomography (SPECT/CT), in asymptomatic diabetic and pre-diabetic patients and to find out whether ischemia predicted the occurrence of adverse cardiac/cerebrovascular events (ACCE) at follow-up. Methods: Forty-three diabetic and thirty-five pre-diabetic asymptomatic patients without any history of coronary artery disease, underwent MPI and were followed-up for a 12.8±2.2 (8-19) months for the occurrence of ACCE. Baseline variables that would predict the presence of ischemia and the value of ischemia on MPI for predicting the occurrence of ACCE at follow-up were evaluated by logistic regression analysis. Results: Ischemia was detected in ten (23.3%) of the diabetic and in four (11.4%) of the pre-diabetic patients. The presence of diabetes was the only independent predictor of myocardial ischemia [odds ratio (OR): 12.31, 95% confidence interval (CI): 1.83-82.66; p<0.01]. During 12.8±2.2 (8-19) months of follow-up, ACCE was observed in five out of 78 (6.4%) patients. Patients with ischemia were significantly more likely to have ACCE during follow-up as compared to those with normal MPI scans (event rates: 21.4% vs. 3.1%, OR: 8.455 95% CI: 1.264-56.562, p=0.038). Conclusion: Myocardial ischemia as detected by adenosine stress SPECT/CT in a population of asymptomatic patients with diabetes mellitus or pre-diabetes appeared to predict the occurrence of ACCE at follow-up. PMID:27277323

  5. Noncontrast perfusion single-photon emission CT/CT scanning: a new test for the expedited, high-accuracy diagnosis of acute pulmonary embolism.

    PubMed

    Lu, Yang; Lorenzoni, Alice; Fox, Josef J; Rademaker, Jürgen; Vander Els, Nicholas; Grewal, Ravinder K; Strauss, H William; Schöder, Heiko

    2014-05-01

    Standard ventilation and perfusion (V˙/Q˙) scintigraphy uses planar images for the diagnosis of pulmonary embolism (PE). To evaluate whether tomographic imaging improves the diagnostic accuracy of the procedure, we compared noncontrast perfusion single-photon emission CT (Q˙-SPECT)/CT scans with planar V˙/Q˙scans in patients at high risk for PE. Between 2006 and 2010, most patients referred for diagnosis of PE underwent both Q˙-SPECT/CT scan and planar V˙/Q˙scintigraphy. All scans were reviewed retrospectively by four observers; planar scans were read with modified Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) II and Prospective Investigative Study of Pulmonary Embolism Diagnosis (PISA-PED) criteria. On Q˙-SPECT/CT scan, any wedge-shaped peripheral perfusion defect occupying > 50% of a segment without corresponding pulmonary parenchymal or pleural disease was considered to show PE. The final diagnosis was established with a composite reference standard that included ECG, ultrasound of lower-extremity veins, D-dimer levels, CT pulmonary angiography (when available), and clinical follow-up for at least 3 months. One hundred six patients with cancer and mean Wells score of 4.4 had sufficient follow-up; 22 patients were given a final diagnosis of PE, and 84 patients were given a final diagnosis of no PE. According to PIOPED II, 13 studies were graded as intermediate probability. Sensitivity and specificity for PE were 50% and 98%, respectively, based on PIOPED II criteria; 86% and 93%, respectively, based on PISA-PED criteria; and 91% and 94%, respectively, based on Q˙-SPECT/CT scan. Seventy-six patients had additional relevant findings on the CT image of the Q˙-SPECT/CT scan. Noncontrast Q˙-SPECT/CT imaging has a higher accuracy than planar V˙/Q˙imaging based on PIOPED II criteria in patients with cancer and a high risk for PE.

  6. Novel Application of Quantitative Single-Photon Emission Computed Tomography/Computed Tomography to Predict Early Response to Methimazole in Graves' Disease

    PubMed Central

    Kim, Hyun Joo; Bang, Ji-In; Kim, Ji-Young; Moon, Jae Hoon; So, Young

    2017-01-01

    Objective Since Graves' disease (GD) is resistant to antithyroid drugs (ATDs), an accurate quantitative thyroid function measurement is required for the prediction of early responses to ATD. Quantitative parameters derived from the novel technology, single-photon emission computed tomography/computed tomography (SPECT/CT), were investigated for the prediction of achievement of euthyroidism after methimazole (MMI) treatment in GD. Materials and Methods A total of 36 GD patients (10 males, 26 females; mean age, 45.3 ± 13.8 years) were enrolled for this study, from April 2015 to January 2016. They underwent quantitative thyroid SPECT/CT 20 minutes post-injection of 99mTc-pertechnetate (5 mCi). Association between the time to biochemical euthyroidism after MMI treatment and %uptake, standardized uptake value (SUV), functional thyroid mass (SUVmean × thyroid volume) from the SPECT/CT, and clinical/biochemical variables, were investigated. Results GD patients had a significantly greater %uptake (6.9 ± 6.4%) than historical control euthyroid patients (n = 20, 0.8 ± 0.5%, p < 0.001) from the same quantitative SPECT/CT protocol. Euthyroidism was achieved in 14 patients at 156 ± 62 days post-MMI treatment, but 22 patients had still not achieved euthyroidism by the last follow-up time-point (208 ± 80 days). In the univariate Cox regression analysis, the initial MMI dose (p = 0.014), %uptake (p = 0.015), and functional thyroid mass (p = 0.016) were significant predictors of euthyroidism in response to MMI treatment. However, only %uptake remained significant in a multivariate Cox regression analysis (p = 0.034). A %uptake cutoff of 5.0% dichotomized the faster responding versus the slower responding GD patients (p = 0.006). Conclusion A novel parameter of thyroid %uptake from quantitative SPECT/CT is a predictive indicator of an early response to MMI in GD patients. PMID:28458607

  7. Noninvasive detection of matrix metalloproteinase-9 in atherosclerotic lesions using technetium-99m-labeled single-photon emission computed tomography in vivo.

    PubMed

    Wang, Zhongjuan; Deng, Gang; Zhang, Zhuiyang; Huang, Hongbo; Zhao, Yanjun

    2017-04-01

    Previous studies have suggested that matrix metalloproteinase (MMP) inhibitor uptake may offer a precise estimation of MMP activity in atherosclerotic lesions. In this study, we explored the feasibility of noninvasive detection of MMP-9 activity using technetium-99m-labeled matrix metalloproteinase-9 antibody (Tc-McAb) in vivo. ApoE-deficient (ApoE) atherosclerosis mice models (n=10) were induced through a high-cholesterol diet following ligation of their left common carotid artery. After 4 weeks, the models were verified through proton density-weighted and T2-weighted images obtained by MRI. C57BL/6 sham mice (n=8) were used as controls. In addition, normal mice (n=20) were used to characterize blood clearance. After radiolabeled McAb administration, single-photon emission computed tomography (SPECT) was performed. Subsequently, left common carotid arteries were harvested for ex-vivo autoradiograph imaging. Then, morphology and activity assays of MMP-9 were histologically and immunohistochemically examined. MRI showed higher signal intensities in the left common carotid arteries with irregular stenoses in the lumen of blood vessels in atherosclerosis mice models in vivo. Atherosclerotic lesions on left common carotid artery specimens were also clearly visualized using SPECT 2 h after Tc-McAb administration in vivo. Note that the radiochemistry purity of the Tc-McAb used was 85-95%. Biodistribution studies have shown that the clearance of Tc-McAb from blood was rapid. In addition, atherosclerotic lesions were clearly visualized on radioautography film shadows ex vivo. MMP-9 activities within the atherosclerotic lesions were noninvasively detected using Tc-labeled SPECT in vivo.

  8. The Added Value of a Single-photon Emission Computed Tomography-Computed Tomography in Sentinel Lymph Node Mapping in Patients with Breast Cancer and Malignant Melanoma.

    PubMed

    Bennie, George; Vorster, Mariza; Buscombe, John; Sathekge, Mike

    2015-01-01

    Single-photon emission computed tomography-computed tomography (SPECT-CT) allows for physiological and anatomical co-registration in sentinel lymph node (SLN) mapping and offers additional benefits over conventional planar imaging. However, the clinical relevance when considering added costs and radiation burden of these reported benefits remains somewhat uncertain. This study aimed to evaluate the possible added value of SPECT-CT and intra-operative gamma-probe use over planar imaging alone in the South African setting. 80 patients with breast cancer or malignant melanoma underwent both planar and SPECT-CT imaging for SLN mapping. We assessed and compared the number of nodes detected on each study, false positive and negative findings, changes in surgical approach and or patient management. In all cases where a sentinel node was identified, SPECT-CT was more accurate anatomically. There was a significant change in surgical approach in 30 cases - breast cancer (n = 13; P 0.001) and malignant melanoma (n = 17; P 0.0002). In 4 cases a node not identified on planar imaging was seen on SPECT-CT. In 16 cases additional echelon nodes were identified. False positives were excluded by SPECT-CT in 12 cases. The addition of SPECT-CT and use of intra-operative gamma-probe to planar imaging offers important benefits in patients who present with breast cancer and melanoma. These benefits include increased nodal detection, elimination of false positives and negatives and improved anatomical localization that ultimately aids and expedites surgical management. This has been demonstrated in the context of industrialized country previously and has now also been confirmed in the setting of a emerging-market nation.

  9. Cost-effectiveness of cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary artery disease in Germany

    PubMed Central

    2013-01-01

    Background Recent studies have demonstrated a superior diagnostic accuracy of cardiovascular magnetic resonance (CMR) for the detection of coronary artery disease (CAD). We aimed to determine the comparative cost-effectiveness of CMR versus single-photon emission computed tomography (SPECT). Methods Based on Bayes’ theorem, a mathematical model was developed to compare the cost-effectiveness and utility of CMR with SPECT in patients with suspected CAD. Invasive coronary angiography served as the standard of reference. Effectiveness was defined as the accurate detection of CAD, and utility as the number of quality-adjusted life-years (QALYs) gained. Model input parameters were derived from the literature, and the cost analysis was conducted from a German health care payer’s perspective. Extensive sensitivity analyses were performed. Results Reimbursement fees represented only a minor fraction of the total costs incurred by a diagnostic strategy. Increases in the prevalence of CAD were generally associated with improved cost-effectiveness and decreased costs per utility unit (ΔQALY). By comparison, CMR was consistently more cost-effective than SPECT, and showed lower costs per QALY gained. Given a CAD prevalence of 0.50, CMR was associated with total costs of €6,120 for one patient correctly diagnosed as having CAD and with €2,246 per ΔQALY gained versus €7,065 and €2,931 for SPECT, respectively. Above a threshold value of CAD prevalence of 0.60, proceeding directly to invasive angiography was the most cost-effective approach. Conclusions In patients with low to intermediate CAD probabilities, CMR is more cost-effective than SPECT. Moreover, lower costs per utility unit indicate a superior clinical utility of CMR. PMID:23574690

  10. Accuracy of early-phase versus dual-phase single-photon emission computed tomography/computed tomography in the localization of parathyroid disease.

    PubMed

    Mandal, Rajarsi; Muthukrishnan, Ashok; Ferris, Robert L; de Almeida, John R; Duvvuri, Umamaheswar

    2015-06-01

    Preoperative localization for parathyroid disease has improved in recent years with the advent of dual-phase (99m) Tc-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) imaging. However, dual-phase imaging is associated with increased cost, time, and radiation dose. The aim of this study was to investigate the need for late-phase imaging when using SPECT/CT for the preoperative localization of parathyroid disease. Retrospective chart analysis. A retrospective review of 75 patients who underwent preoperative imaging localization and subsequent surgical resection for parathyroid disease at a tertiary referral center was performed. Of these, 50 patients met study criteria including preoperative SPECT/CT imaging and specific reporting of early- and late-phase focal radiotracer uptake. Localization accuracy was verified with definitive surgical findings confirmed by histological analysis and evidence of biochemical cure. Accurate localization of adenoma(s) was seen in 78.0% of patients using dual-phase SPECT/CT. Early-phase imaging alone localized 76.0%, whereas late-phase imaging alone localized 74.0%. Sensitivity and specificity for dual-phase imaging was 84.8% and 89.6%, respectively. In comparison, early-phase localization alone was found to have a sensitivity/specificity of 84.4%/89.4%; sensitivity/specificity of late-phase scanning alone was found to be 80.4%/89.1%. Dual-phase SPECT/CT scanning did not provide a statistically significant improvement in adenoma localization when compared to early-phase scanning alone. Although further investigation is needed, the results of this study suggest that early-phase SPECT/CT scanning alone may obviate the need for dual-phase SPECT/CT scanning in the initial preoperative localization workup of parathyroid disease. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  11. Comparison of Single-Photon Emission Computed Tomography-Computed Tomography (SPECT/CT) and Conventional Planar Lymphoscintigraphy for Sentinel Node Localization in Patients with Cutaneous Malignancies.

    PubMed

    Doepker, Matthew P; Yamamoto, Maki; Applebaum, Matthew A; Patel, Nupur U; Jaime Montilla-Soler, M; Sarnaik, Amod A; Wayne Cruse, C; Sondak, Vernon K; Zager, Jonathan S

    2017-02-01

    Accurate preoperative lymphoscintigraphy is vital to performing sentinel lymph node biopsy (SLNB) for cutaneous malignancies. Potential advantages of single-photon emission computed tomography with integrated computed tomography (SPECT/CT) include the ability to readily identify aberrant drainage patterns as well as provide the surgeon with three-dimensional anatomic landmarks not seen on conventional planar lymphoscintigraphy (PLS). Patients with cutaneous malignancies who underwent SLNB with preoperative imaging using both SPECT/CT and PLS from 2011 to 2014 were identified. Both SPECT/CT and PLS were obtained in 351 patients (median age, 69 years; range, 5-94 years) with cutaneous malignancies (melanoma = 300, Merkel cell carcinoma = 33, squamous cell carcinoma = 8, other = 10) after intradermal injection of (99m)technetium sulfur colloid (median dose 300 µCi). A mean of 4.3 hot spots were identified on SPECT/CT compared to 3.0 on PLS (p < 0.001). One hundred fifty-three patients (43.6 %) had identical findings between SPECT/CT and PLS, while 172 (49 %) had additional hot spots identified on SPECT/CT compared to only 24 (6.8 %) additional on PLS. SPECT/CT demonstrated additional nodal basins in 103 patients (29.4 %), compared to only 11 patients (3.1 %) with additional basins on PLS. SPECT/CT is a useful adjunct that can help with sentinel node localization in challenging cases. It identified additional hot spots not seen on PLS in almost 50 % of patients. Because PLS identified hot spots not seen on SPECT/CT in 6.8 % of patients, we recommend using both modalities jointly. Long-term follow-up will be required to validate the clinical significance of the additional hot spots identified by SPECT/CT.

  12. Sensitivity and Specificity of Dual-Isotope 99mTc-Tetrofosmin and 123I Sodium Iodide Single Photon Emission Computed Tomography (SPECT) in Hyperparathyroidism

    PubMed Central

    Sommerauer, Michael; Graf, Carmen; Schäfer, Niklaus; Huber, Gerhard; Schneider, Paul; Wüthrich, Rudolf; Schmid, Christoph; Steinert, Hans

    2015-01-01

    Purpose Despite recommendations for 99mTc-tetrofosmin dual tracer imaging for hyperparathyroidism in current guidelines, no report was published on dual-isotope 99mTc-tetrofosmin and 123I sodium iodide single-photon-emission-computed-tomography (SPECT). We evaluated diagnostic accuracy and the impact of preoperative SPECT on the surgical procedures and disease outcomes. Methods Analysis of 70 consecutive patients with primary hyperparathyroidism and 20 consecutive patients with tertiary hyperparathyroidism. Imaging findings were correlated with surgical results. Concomitant thyroid disease, pre- and postoperative laboratory measurements, histopathological results, type and duration of surgery were assessed. Results In primary hyperparathyroidism, SPECT had a sensitivity of 80% and a positive predictive value of 93% in patient-based analysis. Specificity was 99% in lesion-based analysis. Patients with positive SPECT elicit higher levels of parathyroid hormone and higher weight of resected parathyroids than SPECT-negative patients. Duration of parathyroid surgery was on average, approximately 40 minutes shorter in SPECT-positive than in SPECT-negative patients (89±46 vs. 129±41 minutes, p=0.006); 86% of SPECT-positive and 50% of SPECT-negative patients had minimal invasive surgery (p = 0.021). SPECT had lower sensitivity (60%) in patients with tertiary hyperparathyroidism; however, 90% of these patients had multiple lesions and all of these patients had bilateral lesions. Conclusion Dual-isotope SPECT with 99mTc-tetrofosmin and 123I sodium iodide has a high diagnostic value in patients with primary hyperparathyroidism and allows for saving of operation time. Higher levels of parathyroid hormone and higher glandular weight facilitated detection of parathyroid lesion. Diagnostic accuracy of preoperative imaging was lower in patients with tertiary hyperparathyroidism. PMID:26079132

  13. Risk of node metastasis of sentinel lymph nodes detected in level II/III of the axilla by single-photon emission computed tomography/computed tomography.

    PubMed

    Shima, Hiroaki; Kutomi, Goro; Satomi, Fukino; Maeda, Hideki; Takamaru, Tomoko; Kameshima, Hidekazu; Omura, Tosei; Mori, Mitsuru; Hatakenaka, Masamitsu; Hasegawa, Tadashi; Hirata, Koichi

    2014-11-01

    In breast cancer, single-photon emission computed tomography/computed tomography (SPECT/CT) shows the exact anatomical location of sentinel nodes (SN). SPECT/CT mainly exposes axilla and partly exposes atypical sites of extra-axillary lymphatic drainage. The mechanism of how the atypical hot nodes are involved in lymphatic metastasis was retrospectively investigated in the present study, particularly at the level II/III region. SPECT/CT was performed in 92 clinical stage 0-IIA breast cancer patients. Sentinel lymph nodes are depicted as hot nodes in SPECT/CT. Patients were divided into two groups: With or without hot node in level II/III on SPECT/CT. The existence of metastasis in level II/III was investigated and the risk factors were identified. A total of 12 patients were sentinel lymph node biopsy metastasis positive and axillary lymph node dissection (ALND) was performed. These patients were divided into two groups: With and without SN in level II/III, and nodes in level II/III were pathologically proven. In 11 of the 92 patients, hot nodes were detected in level II/III. There was a significant difference in node metastasis depending on whether there were hot nodes in level II/III (P=0.0319). Multivariate analysis indicated that the hot nodes in level II/III and lymphatic invasion were independent factors associated with node metastasis. There were 12 SN-positive patients followed by ALND. In four of the 12 patients, hot nodes were observed in level II/III. Two of the four patients with hot nodes depicted by SPECT/CT and metastatic nodes were pathologically evident in the same lesion. Therefore, the present study indicated that the hot node in level II/III as depicted by SPECT/CT may be a risk of SN metastasis, including deeper nodes.

  14. Incidence of a single subsegmental mismatched perfusion defect in single-photon emission computed tomography and planar ventilation/perfusion scans.

    PubMed

    Stubbs, Matthew; Chan, Kenneth; McMeekin, Helena; Navalkissoor, Shaunak; Wagner, Thomas

    2017-02-01

    This study aims to compare the incidence of ventilation/perfusion (V/Q) scans interpreted as indeterminate for the diagnosis of pulmonary embolism (PE) using single-photon emission computed tomography (SPECT) versus planar scintigraphy and to consider the effect of variable interpretation of single subsegmental V/Q mismatch (SSM). A total of 1300 consecutive V/Q scans were retrospectively reviewed. After exclusion and matching for age and sex, 542 SPECT and 589 planar scans were included in the analysis. European Association of Nuclear Medicine guidelines were used to interpret the V/Q scans, initially interpreting SSM as negative scans. Patients with SSM were followed up for 3 months and further imaging for PE was collected. Indeterminate scans were significantly fewer in the SPECT than the planar group on the basis of the initial report (7.7 vs. 12.2%, P<0.05). This is irrespective of classification of SSM as a negative scan (4.6 vs. 12.1%, P<0.0001) or an indeterminate scan (8.3 vs. 12.2%, P<0.05). Of the 21 patients who had SSM, 19 underwent computer tomography pulmonary angiogram and embolism was found in one patient. None of these patients died at the 3-month follow-up. V/Q SPECT has greater diagnostic certainty of PE, with a 41% reduction in an indeterminate scan compared with planar scintigraphy. This is irrespective of the clinician's interpretation of SSM as negative or intermediate probability. Patients with SSM would not require further computer tomography pulmonary angiogram imaging.

  15. Development of (99m)Tc-labeled asymmetric urea derivatives that target prostate-specific membrane antigen for single-photon emission computed tomography imaging.

    PubMed

    Kimura, Hiroyuki; Sampei, Sotaro; Matsuoka, Daiko; Harada, Naoya; Watanabe, Hiroyuki; Arimitsu, Kenji; Ono, Masahiro; Saji, Hideo

    2016-05-15

    Prostate-specific membrane antigen (PSMA) is expressed strongly in prostate cancers and is, therefore, an attractive diagnostic and radioimmunotherapeutic target. In contrast to previous reports of PMSA-targeting (99m)Tc-tricarbonyl complexes that are cationic or lack a charge, no anionic (99m)Tc-tricarbonyl complexes have been reported. Notably, the hydrophilicity conferred by both cationic and anionic charges leads to rapid hepatobiliary clearance, whereas an anionic charge might better enhance renal clearance relative to a cationic charge. Therefore, an improvement in rapid clearance would be expected with either cationic or anionic charges, particularly anionic charges. In this study, we designed and synthesized a novel anionic (99m)Tc-tricarbonyl complex ([(99m)Tc]TMCE) and evaluated its use as a single-photon emission computed tomography (SPECT) imaging probe for PSMA detection. Direct synthesis of [(99m)Tc]TMCE from dimethyl iminodiacetate, which contains both the asymmetric urea and succinimidyl moiety important for PSMA binding, was performed using our microwave-assisted one-pot procedure. The chelate formation was successfully achieved even though the precursor included a complicated bioactive moiety. The radiochemical yield of [(99m)Tc]TMCE was 12-17%, with a radiochemical purity greater than 98% after HPLC purification. [(99m)Tc]TMCE showed high affinity in vitro, with high accumulation in LNCaP tumors and low hepatic retention in biodistribution and SPECT/CT studies. These findings warrant further evaluation of [(99m)Tc]TMCE as an imaging agent and support the benefit of this strategy for the design of other PSMA imaging probes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. The Added Value of a Single-photon Emission Computed Tomography-Computed Tomography in Sentinel Lymph Node Mapping in Patients with Breast Cancer and Malignant Melanoma

    PubMed Central

    Bennie, George; Vorster, Mariza; Buscombe, John; Sathekge, Mike

    2015-01-01

    Single-photon emission computed tomography-computed tomography (SPECT-CT) allows for physiological and anatomical co-registration in sentinel lymph node (SLN) mapping and offers additional benefits over conventional planar imaging. However, the clinical relevance when considering added costs and radiation burden of these reported benefits remains somewhat uncertain. This study aimed to evaluate the possible added value of SPECT-CT and intra-operative gamma-probe use over planar imaging alone in the South African setting. 80 patients with breast cancer or malignant melanoma underwent both planar and SPECT-CT imaging for SLN mapping. We assessed and compared the number of nodes detected on each study, false positive and negative findings, changes in surgical approach and or patient management. In all cases where a sentinel node was identified, SPECT-CT was more accurate anatomically. There was a significant change in surgical approach in 30 cases - breast cancer (n = 13; P 0.001) and malignant melanoma (n = 17; P 0.0002). In 4 cases a node not identified on planar imaging was seen on SPECT-CT. In 16 cases additional echelon nodes were identified. False positives were excluded by SPECT-CT in 12 cases. The addition of SPECT-CT and use of intra-operative gamma-probe to planar imaging offers important benefits in patients who present with breast cancer and melanoma. These benefits include increased nodal detection, elimination of false positives and negatives and improved anatomical localization that ultimately aids and expedites surgical management. This has been demonstrated in the context of industrialized country previously and has now also been confirmed in the setting of a emerging-market nation. PMID:25709544

  17. Sensitivity and Specificity of Dual-Isotope 99mTc-Tetrofosmin and 123I Sodium Iodide Single Photon Emission Computed Tomography (SPECT) in Hyperparathyroidism.

    PubMed

    Sommerauer, Michael; Graf, Carmen; Schäfer, Niklaus; Huber, Gerhard; Schneider, Paul; Wüthrich, Rudolf; Schmid, Christoph; Steinert, Hans

    2015-01-01

    Despite recommendations for 99mTc-tetrofosmin dual tracer imaging for hyperparathyroidism in current guidelines, no report was published on dual-isotope 99mTc-tetrofosmin and 123I sodium iodide single-photon-emission-computed-tomography (SPECT). We evaluated diagnostic accuracy and the impact of preoperative SPECT on the surgical procedures and disease outcomes. Analysis of 70 consecutive patients with primary hyperparathyroidism and 20 consecutive patients with tertiary hyperparathyroidism. Imaging findings were correlated with surgical results. Concomitant thyroid disease, pre- and postoperative laboratory measurements, histopathological results, type and duration of surgery were assessed. In primary hyperparathyroidism, SPECT had a sensitivity of 80% and a positive predictive value of 93% in patient-based analysis. Specificity was 99% in lesion-based analysis. Patients with positive SPECT elicit higher levels of parathyroid hormone and higher weight of resected parathyroids than SPECT-negative patients. Duration of parathyroid surgery was on average, approximately 40 minutes shorter in SPECT-positive than in SPECT-negative patients (89 ± 46 vs. 129 ± 41 minutes, p = 0.006); 86% of SPECT-positive and 50% of SPECT-negative patients had minimal invasive surgery (p = 0.021). SPECT had lower sensitivity (60%) in patients with tertiary hyperparathyroidism; however, 90% of these patients had multiple lesions and all of these patients had bilateral lesions. Dual-isotope SPECT with 99mTc-tetrofosmin and 123I sodium iodide has a high diagnostic value in patients with primary hyperparathyroidism and allows for saving of operation time. Higher levels of parathyroid hormone and higher glandular weight facilitated detection of parathyroid lesion. Diagnostic accuracy of preoperative imaging was lower in patients with tertiary hyperparathyroidism.

  18. Assessment of Inter-modality Spatial Alignment Accuracy in Hybrid Single Photon Emission Computed Tomography in Patients with Hand and Wrist Pain

    PubMed Central

    Xie, Cheng; Gnanasegaran, Gopinath; Mohan, Hosahalli; Livieratos, Lefteris

    2013-01-01

    Single photon emission computed tomography (SPECT) and computed tomography (CT) integrated in one system (SPECT/CT) is an effective co-registration technique that helps to localize and characterize lesions in the hand and wrist. However, patient motion may cause misalignment between the two modalities leading to potential misdiagnosis. The aim of the present study was to evaluate the hardware-based registration accuracy of multislice SPECT/CT of the hand and wrist and to determine the effect of misalignment errors on diagnostic accuracy. A total of 55 patients who had multislice SPECT/CT of the hand and wrist between July 2008 and January 2010 were included. Two reviewers independently evaluated the fused images for any misalignments with six degrees of freedom: Translation and rotation in the X, Y and Z directions. The results were tested against an automated fusion tool (Syntegra). More than half of the patients had moved during SPECT scanning (Reviewer 1: 29 patients; Reviewer 2: 30 patients) and they all originated in the Y-direction translation (vertical hand motion). Five fused images had significant misalignment errors that could have led to misdiagnosis. The Wilcoxon test indicated statistically non-significant difference (P > 0.05) between reviewers and statistically non-significant difference between the reviewers and software registration. The study also showed high inter-reviewer agreement (κ = 0.87). Hand movement during the SPECT scan was common, but significant misalignments and subsequent misdiagnosis were infrequent. Future studies should investigate the use of hand and wrist immobilization devices and reductions of scan time to minimize patient motion. PMID:25214811

  19. Differentiation of myocardial ischemia and infarction assessed by dynamic computed tomography perfusion imaging and comparison with cardiac magnetic resonance and single-photon emission computed tomography.

    PubMed

    Tanabe, Yuki; Kido, Teruhito; Uetani, Teruyoshi; Kurata, Akira; Kono, Tamami; Ogimoto, Akiyoshi; Miyagawa, Masao; Soma, Tsutomu; Murase, Kenya; Iwaki, Hirotaka; Mochizuki, Teruhito

    2016-11-01

    To evaluate the feasibility of myocardial blood flow (MBF) by computed tomography from dynamic CT perfusion (CTP) for detecting myocardial ischemia and infarction assessed by cardiac magnetic resonance (CMR) or single-photon emission computed tomography (SPECT). Fifty-three patients who underwent stress dynamic CTP and either SPECT (n = 25) or CMR (n = 28) were retrospectively selected. Normal and abnormal perfused myocardium (ischemia/infarction) were assessed by SPECT/CMR using 16-segment model. Sensitivity and specificity of CT-MBF (mL/g/min) for detecting the ischemic/infarction and severe infarction were assessed. The abnormal perfused myocardium and severe infarction were seen in SPECT (n = 90 and n = 19 of 400 segments) and CMR (n = 223 and n = 36 of 448 segments). For detecting the abnormal perfused myocardium, sensitivity and specificity were 80 % (95 %CI, 71-90) and 86 % (95 %CI, 76-91) in SPECT (cut-off MBF, 1.23), and 82 % (95 %CI, 76-88) and 87 % (95 %CI, 80-92) in CMR (cut-off MBF, 1.25). For detecting severe infarction, sensitivity and specificity were 95 % (95 %CI, 52-100) and 72 % (95 %CI, 53-91) in SPECT (cut-off MBF, 0.92), and 78 % (95 %CI, 67-97) and 80 % (95 %CI, 58-86) in CMR (cut-off MBF, 0.98), respectively. Dynamic CTP has a potential to detect abnormal perfused myocardium and severe infarction assessed by SPECT/CMR using comparable cut-off MBF. • CT-MBF accurately reflects the severity of myocardial perfusion abnormality. • CT-MBF provides good diagnostic accuracy for detecting myocardial perfusion abnormalities. • CT-MBF may assist in stratifying severe myocardial infarction in abnormal perfusion myocardium.

  20. Impact of Follow-Up Ischemia on Myocardial Perfusion Single-Photon Emission Computed Tomography in Patients with Coronary Artery Disease

    PubMed Central

    Kang, Se Hun; Choi, Hyo In; Lee, Eun Young; Ahn, Jung-Min; Han, Seungbong; Lee, Pil Hyung; Roh, Jae-Hyung; Yun, Sung-Han; Park, Duk-Woo; Kang, Soo-Jin; Lee, Seung-Whan; Lee, Cheol Whan; Moon, Dae Hyuk; Park, Seong-Wook; Park, Seung-Jung

    2017-01-01

    Purpose Few studies have reported on predicting prognosis using myocardial perfusion single-photon emission computed tomography (SPECT) during coronary artery disease (CAD) treatment. Therefore, we aimed to assess the clinical implications of myocardial perfusion SPECT during follow-up for CAD treatment. Materials and Methods We enrolled 1153 patients who had abnormal results at index SPECT and underwent follow-up SPECT at intervals ≥6 months. Major adverse cardiac events (MACE) were compared in overall and 346 patient pairs after propensity-score (PS) matching. Results Abnormal SPECT was associated with a significantly higher risk of MACE in comparison with normal SPECT over the median of 6.3 years (32.3% vs. 19.8%; unadjusted p<0.001). After PS matching, abnormal SPECT posed a higher risk of MACE [32.1% vs. 19.1%; adjusted hazard ratio (HR)=1.73; 95% confidence interval (CI)=1.27–2.34; p<0.001] than normal SPECT. After PS matching, the risk of MACE was still higher in patients with abnormal follow-up SPECT in the revascularization group (30.2% vs. 17.9%; adjusted HR=1.73; 95% CI=1.15–2.59; p=0.008). Low ejection fraction [odds ratio (OR)=5.33; 95% CI=3.39–8.37; p<0.001] and medical treatment (OR=2.68; 95% CI=1.93–3.72; p<0.001) were independent clinical predictors of having an abnormal result on follow-up SPECT. Conclusion Abnormal follow-up SPECT appears to be associated with a high risk of MACE during CAD treatment. Follow-up SPECT may play a potential role in identifying patients at high cardiovascular risk. PMID:28792136

  1. Factors affecting the sensitivity of Tc-99m methoxyisobutylisonitrile dual-phase parathyroid single photon emission computed tomography in primary hyperparathyroidism.

    PubMed

    Araz, Mine; Çayir, Derya; Erdoğan, Mehmet; Uçan, Bekir; Çakal, Erman

    2017-02-01

    The aim of this study was to investigate the effects of thyroid diseases and regularly used medications on the sensitivity of Tc-99m methoxyisobutylisonitrile (MIBI) dual-phase parathyroid single photon emission computed tomography (SPECT) and to define indicatives of the result of the study. Overall, 218 primary hyperparathyroidism patients (190 women, 28 men, mean age: 57±14 years) with thyroid-parathyroid ultrasonography and Tc-99m MIBI dual-phase parathyroid SPECT were retrospectively enrolled. Patients were divided as follows: a positive SPECT group [119 (54.6%) patients] and a negative SPECT group [99 (45.4%) patients]. The effects of thyroid diseases and use of calcium channel blockers, β-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, oral antidiabetics, thyroid hormone preparates, nonsteroidal anti-inflammatory drugs, and proton pump inhibitors on the sensitivity of Tc-99m MIBI dual-phase parathyroid SPECT were investigated. The frequency of NSAID usage was higher in the negative scan group (P<0.001). No significant difference was detected in terms of coexisting thyroid disease or usage of other medications. Overall sensitivity, specificity, positive, and negative predictive value of Tc-99m MIBI dual-phase parathyroid SPECT were calculated to be 89.6, 92.5, 94.1, and 86.9%. The sensitivity was low only in nonsteroidal anti-inflammatory drug users (75.6%) compared with nonusers (96.5%). Logistic regression showed that ultrasonography was indicative of a positive scan and the possibility of a negative result was increased by regular usage of nonsteroid anti-inflammatory drugs (odds ratio: 0.262, confidence interval: 0.128-0.538; P<0.001) CONCLUSION: Among various drug groups, NSAIDs may decrease the sensitivity of Tc-99m MIBI SPECT and, provided that these novel data are supported by other studies, patient preparation may be modified to stop NSAIDs before Tc-99m MIBI dual-phase parathyroid SPECT.

  2. The predictive value of single-photon emission computed tomography/computed tomography for sentinel lymph node localization in head and neck cutaneous malignancy.

    PubMed

    Remenschneider, Aaron K; Dilger, Amanda E; Wang, Yingbing; Palmer, Edwin L; Scott, James A; Emerick, Kevin S

    2015-04-01

    Preoperative localization of sentinel lymph nodes in head and neck cutaneous malignancies can be aided by single-photon emission computed tomography/computed tomography (SPECT/CT); however, its true predictive value for identifying lymph nodes intraoperatively remains unquantified. This study aims to understand the sensitivity, specificity, and positive and negative predictive values of SPECT/CT in sentinel lymph node biopsy for cutaneous malignancies of the head and neck. Blinded retrospective imaging review with comparison to intraoperative gamma probe confirmed sentinel lymph nodes. A consecutive series of patients with a head and neck cutaneous malignancy underwent preoperative SPECT/CT followed by sentinel lymph node biopsy with a gamma probe. Two nuclear medicine physicians, blinded to clinical data, independently reviewed each SPECT/CT. Activity within radiographically defined nodal basins was recorded and compared to intraoperative gamma probe findings. Sensitivity, specificity, and negative and positive predictive values were calculated with subgroup stratification by primary tumor site. Ninety-two imaging reads were performed on 47 patients with cutaneous malignancy who underwent SPECT/CT followed by sentinel lymph node biopsy. Overall sensitivity was 73%, specificity 92%, positive predictive value 54%, and negative predictive value 96%. The predictive ability of SPECT/CT to identify the basin or an adjacent basin containing the single hottest node was 92%. SPECT/CT overestimated uptake by an average of one nodal basin. In the head and neck, SPECT/CT has higher reliability for primary lesions of the eyelid, scalp, and cheek. SPECT/CT has high sensitivity, specificity, and negative predictive value, but may overestimate relevant nodal basins in sentinel lymph node biopsy. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  3. Prediction of sentinel lymph node status using single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of breast cancer.

    PubMed

    Tomiguchi, Mai; Yamamoto-Ibusuki, Mutsuko; Yamamoto, Yutaka; Fujisue, Mamiko; Shiraishi, Shinya; Inao, Touko; Murakami, Kei-ichi; Honda, Yumi; Yamashita, Yasuyuki; Iyama, Ken-ichi; Iwase, Hirotaka

    2016-02-01

    Single-photon emission computed tomography (SPECT)/computed tomography (CT) improves the anatomical identification of sentinel lymph nodes (SNs). We aimed to evaluate the possibility of predicting the SN status using SPECT/CT. SN mapping using a SPECT/CT system was performed in 381 cases of clinically node-negative, operable invasive breast cancer. We evaluated and compared the values of SN mapping on SPECT/CT, the findings of other modalities and clinicopathological factors in predicting the SN status. Patients with SNs located in the Level I area were evaluated. Of the 355 lesions (94.8 %) assessed, six cases (1.6 %) were not detected using any imaging method. According to the final histological diagnosis, 298 lesions (78.2 %) were node negative and 83 lesions (21.7 %) were node positive. The univariate analysis showed that SN status was significantly correlated with the number of SNs detected on SPECT/CT in the Level I area (P = 0.0048), total number of SNs detected on SPECT/CT (P = 0.011), findings of planar lymphoscintigraphy (P = 0.011) and findings of a handheld gamma probe during surgery (P = 0.012). According to the multivariate analysis, the detection of multiple SNs on SPECT/CT imaging helped to predict SN metastasis. The number of SNs located in the Level I area detected using the SPECT/CT system may be a predictive factor for SN metastasis.

  4. Additional Value of Brachial-Ankle Pulse Wave Velocity to Single-Photon Emission Computed Tomography in the Diagnosis of Coronary Artery Disease.

    PubMed

    Jang, Kyeongmin; Kim, Hack-Lyoung; Park, Miri; Oh, Sohee; Oh, So Won; Lim, Woo-Hyun; Seo, Jae-Bin; Kim, Sang-Hyun; Zo, Joo-Hee; Kim, Myung-A

    2017-08-24

    The aim of this study was to investigate whether information on arterial stiffness can improve the value of single-photon emission computed tomography (SPECT) in the detection of obstructive coronary artery disease (CAD). A total of 233 patients (age: 62.2±10.8 years, 60.3% males) with detected ischemia on SPECT undergoing invasive coronary angiography (ICA) and brachial-ankle pulse wave velocity (baPWV) measurement within a month was retrospectively reviewed. Of the 233 patients, 190 (81.5%) had obstructive CAD (≥50% luminal stenosis). The difference in baPWV according to the presence of obstructive CAD was significant in patients in the mild ischemia group [summed stress score (SSS): 4-8] (1,770±364 cm versus 1,490±328 cm, p<0.001) but not in the moderate (SSS: 9-13) or severe (SSS: ≥14) ischemia groups (p>0.05 for each). Receiver operating characteristic curve analyses showed that the diagnostic value of baPWV for obstructive CAD was significant only in patients in the mild ischemia group (area under curve: 0.714; p=0.001) but not in the moderate or severe ischemia groups (p>0.05 for each). Adding information on baPWV to SPECT results and clinical parameters significantly increased diagnostic accuracy in the detection of obstructive CAD in patients with mild ischemia (integrated discrimination improvement p=0.006) but not in those with moderate or severe ischemia on SPECT (p>0.05 for each). The results of this study suggest that baPWV may have additional value to SPECT for the detection of obstructive CAD, especially in patients with mild ischemia on SPECT.

  5. Incremental prognostic value of sequential imaging of single-photon emission computed tomography and coronary computed tomography angiography in patients with suspected coronary artery disease.

    PubMed

    Kim, Hack-Lyoung; Kim, Yong-Jin; Lee, Seung-Pyo; Park, Eun-Ah; Paeng, Jin-Chul; Kim, Hyung-Kwan; Lee, Whal; Cho, Goo-Yeong; Zo, Joo-Hee; Choi, Dong-Ju; Sohn, Dae-Won

    2014-08-01

    This study was conducted to investigate the incremental prognostic value of sequential use of single-photon emission computed tomography (SPECT) and coronary computed tomography angiography (CCTA) in patients with suspected coronary artery disease (CAD). A total of 1295 patients with suspected CAD who underwent both CCTA and SPECT within 90 days was retrospectively reviewed in three cardiac centres. Cardiovascular events including cardiac death, non-fatal myocardial infarction, unstable angina, and late (> 90 days of imaging tests) revascularization were assessed. During the mean follow-up period of 795 ± 566 days (median, 735 days), there were 109 events (8.4%). Perfusion defect on SPECT and significant stenosis (≥ 50%) on CCTA were independent predictors for events. Sequential use of both imaging tests significantly improved prediction of the cardiovascular events. The incremental prognostic value of SPECT was significant in patients with stenosis of <90% but not in patients with stenosis of ≥ 90% on CCTA. Similarly, the incremental prognostic value of CCTA was significant in patients with the summed stress score (SSS) <4 but not in patients with SSS ≥ 4 on SPECT. Sequential use of SPECT and CCTA showed an incremental prognostic value in patients with suspected CAD. However, additional benefits were not significant when CCTA revealed stenosis of ≥ 90% or SPECT revealed SSS ≥ 4. These results suggest an effective risk stratification strategy for sequential use of SPECT and CCTA, and maximizing the benefits in these patients. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  6. Normal values of cardiac mechanical synchrony parameters using gated myocardial perfusion single-photon emission computed tomography: Impact of population and study protocol

    PubMed Central

    Mukherjee, Anirban; Singh, Harmandeep; Patel, Chetan; Sharma, Gautam; Roy, Ambuj; Naik, Nitish

    2016-01-01

    Purpose of the Study: Normal values of cardiac mechanical synchrony parameters in gated myocardial perfusion single-photon emission computed tomography (GMPS) are well established in literature from the Western population. The aim of the study is to establish normal values of mechanical synchrony with GMPS in Indian population and to find out whether it differs significantly from established values. Procedure: We retrospectively analyzed 1 day low-dose stress/high-dose rest GMPS studies of 120 patients (sixty males, 52 ± 11.7 years) with low pretest likelihood of coronary artery disease and having normal GMPS study. In GMPS, first-harmonic fast Fourier transform was used to extract a phase array using commercially available software. Phase standard deviation (PSD) and phase histogram bandwidth (PHB) were used to quantify cardiac mechanical dyssynchrony. Results: The values obtained were as follows, PSD: In men, 14.3 ± 4.7 (stress) and 8.9 ± 2.9 (rest), in women 11 ± 4 (stress) and 7.7 ± 2.7 (rest), and PHB: In men, 40.1 ± 11.9 (stress) and 30.6 ± 7.6 (rest), in women, 34.7 ± 12.6 (stress) and 25.3 ± 8.6 (rest). The value of PSD and PHB was significantly less in Indian population as compared with established values in literature. We also observed that synchrony indices derived from the low-dose stress studies are higher than high-dose rest studies. Conclusions: The value of synchrony parameters differs significantly according to population and methodology suggesting that specific population and methodology-based normal database for assessment of cardiac mechanical dyssynchrony should be established. PMID:27833309

  7. Correlation of Uptake Patterns on Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and Treatment Response in Patients with Knee Pain.

    PubMed

    Koh, Geon; Hwang, Kyung Hoon; Lee, Haejun; Kim, Seog Gyun; Lee, Beom Koo

    2016-06-01

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

  8. Novel Application of Quantitative Single-Photon Emission Computed Tomography/Computed Tomography to Predict Early Response to Methimazole in Graves' Disease.

    PubMed

    Kim, Hyun Joo; Bang, Ji-In; Kim, Ji-Young; Moon, Jae Hoon; So, Young; Lee, Won Woo

    2017-01-01

    Since Graves' disease (GD) is resistant to antithyroid drugs (ATDs), an accurate quantitative thyroid function measurement is required for the prediction of early responses to ATD. Quantitative parameters derived from the novel technology, single-photon emission computed tomography/computed tomography (SPECT/CT), were investigated for the prediction of achievement of euthyroidism after methimazole (MMI) treatment in GD. A total of 36 GD patients (10 males, 26 females; mean age, 45.3 ± 13.8 years) were enrolled for this study, from April 2015 to January 2016. They underwent quantitative thyroid SPECT/CT 20 minutes post-injection of (99m)Tc-pertechnetate (5 mCi). Association between the time to biochemical euthyroidism after MMI treatment and %uptake, standardized uptake value (SUV), functional thyroid mass (SUVmean × thyroid volume) from the SPECT/CT, and clinical/biochemical variables, were investigated. GD patients had a significantly greater %uptake (6.9 ± 6.4%) than historical control euthyroid patients (n = 20, 0.8 ± 0.5%, p < 0.001) from the same quantitative SPECT/CT protocol. Euthyroidism was achieved in 14 patients at 156 ± 62 days post-MMI treatment, but 22 patients had still not achieved euthyroidism by the last follow-up time-point (208 ± 80 days). In the univariate Cox regression analysis, the initial MMI dose (p = 0.014), %uptake (p = 0.015), and functional thyroid mass (p = 0.016) were significant predictors of euthyroidism in response to MMI treatment. However, only %uptake remained significant in a multivariate Cox regression analysis (p = 0.034). A %uptake cutoff of 5.0% dichotomized the faster responding versus the slower responding GD patients (p = 0.006). A novel parameter of thyroid %uptake from quantitative SPECT/CT is a predictive indicator of an early response to MMI in GD patients.

  9. Impact of Follow-Up Ischemia on Myocardial Perfusion Single-Photon Emission Computed Tomography in Patients with Coronary Artery Disease.

    PubMed

    Kang, Se Hun; Choi, Hyo In; Kim, Young Hak; Lee, Eun Young; Ahn, Jung Min; Han, Seungbong; Lee, Pil Hyung; Roh, Jae Hyung; Yun, Sung Han; Park, Duk Woo; Kang, Soo Jin; Lee, Seung Whan; Lee, Cheol Whan; Moon, Dae Hyuk; Park, Seong Wook; Park, Seung Jung

    2017-09-01

    Few studies have reported on predicting prognosis using myocardial perfusion single-photon emission computed tomography (SPECT) during coronary artery disease (CAD) treatment. Therefore, we aimed to assess the clinical implications of myocardial perfusion SPECT during follow-up for CAD treatment. We enrolled 1153 patients who had abnormal results at index SPECT and underwent follow-up SPECT at intervals ≥6 months. Major adverse cardiac events (MACE) were compared in overall and 346 patient pairs after propensity-score (PS) matching. Abnormal SPECT was associated with a significantly higher risk of MACE in comparison with normal SPECT over the median of 6.3 years (32.3% vs. 19.8%; unadjusted p<0.001). After PS matching, abnormal SPECT posed a higher risk of MACE [32.1% vs. 19.1%; adjusted hazard ratio (HR)=1.73; 95% confidence interval (CI)=1.27-2.34; p<0.001] than normal SPECT. After PS matching, the risk of MACE was still higher in patients with abnormal follow-up SPECT in the revascularization group (30.2% vs. 17.9%; adjusted HR=1.73; 95% CI=1.15-2.59; p=0.008). Low ejection fraction [odds ratio (OR)=5.33; 95% CI=3.39-8.37; p<0.001] and medical treatment (OR=2.68; 95% CI=1.93-3.72; p<0.001) were independent clinical predictors of having an abnormal result on follow-up SPECT. Abnormal follow-up SPECT appears to be associated with a high risk of MACE during CAD treatment. Follow-up SPECT may play a potential role in identifying patients at high cardiovascular risk.

  10. Diagnostic value of single-photon emission computed tomography combined with computed tomography in relation to MRI on osteochondral lesions of the talus.

    PubMed

    Tamam, Cuneyt; Tamam, Muge O; Yildirim, Duzgun; Mulazimoglu, Mehmet

    2015-08-01

    Osteochondral lesion of the talus (OLT) involves the separation of a fragment of articular cartilage, as defined by Kappis in 1922. MRI is the current standard for noninvasive diagnosis of OLT. Single-photon emission computed tomography combined with computed tomography (SPECT/CT) provides both morphologic and functional information. The purpose of the study was to compare SPECT/CT with MRI for image interpretation and treatment decision making in talar osteochondral lesions. A total of 21 patients (four bilateral) were evaluated with MRI and SPECT/CT. Diagnostic arthroscopy was performed to validate the indication by identifying unstable cartilage areas. Activation was assessed in nine regions of interest, as described by Elias and colleagues. SPECT/CT findings were assessed by the modified scoring system of Hart and colleagues, and MRI findings with the modified classification system of Hepple and colleagues. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for SPECT/CT and MRI. A total of 25 lesions were identified. Seventeen lesions were located on the medial third of the talar dome, eight on the lateral third, and seven on the central third. Four patients revealed diffuse uptake on more than one zone on SPECT/CT. SPECT/CT identified two subchondral lesions, which were not visualized on MRI. MRI is the current standard for OLT diagnosis. SPECT/CT allows a three-dimensional localization of scintigraphic osteoblastic activity in the area of interest, providing additional information about the involvement of the subchondral bone and the vitality of the osteochondral lesion and the location of multiple lesions. We recommend the use of SPECT/CT and MRI together for comprehensive diagnostic assessment of OLT.

  11. Quantitative estimation of infarct size by simultaneous dual radionuclide single photon emission computed tomography: comparison with peak serum creatine kinase activity

    SciTech Connect

    Kawaguchi, K.; Sone, T.; Tsuboi, H.; Sassa, H.; Okumura, K.; Hashimoto, H.; Ito, T.; Satake, T. )

    1991-05-01

    To test the hypothesis that simultaneous dual energy single photon emission computed tomography (SPECT) with technetium-99m (99mTc) pyrophosphate and thallium-201 (201TI) can provide an accurate estimate of the size of myocardial infarction and to assess the correlation between infarct size and peak serum creatine kinase activity, 165 patients with acute myocardial infarction underwent SPECT 3.2 +/- 1.3 (SD) days after the onset of acute myocardial infarction. In the present study, the difference in the intensity of 99mTc-pyrophosphate accumulation was assumed to be attributable to difference in the volume of infarcted myocardium, and the infarct volume was corrected by the ratio of the myocardial activity to the osseous activity to quantify the intensity of 99mTc-pyrophosphate accumulation. The correlation of measured infarct volume with peak serum creatine kinase activity was significant (r = 0.60, p less than 0.01). There was also a significant linear correlation between the corrected infarct volume and peak serum creatine kinase activity (r = 0.71, p less than 0.01). Subgroup analysis showed a high correlation between corrected volume and peak creatine kinase activity in patients with anterior infarctions (r = 0.75, p less than 0.01) but a poor correlation in patients with inferior or posterior infarctions (r = 0.50, p less than 0.01). In both the early reperfusion and the no reperfusion groups, a good correlation was found between corrected infarct volume and peak serum creatine kinase activity (r = 0.76 and r = 0.76, respectively; p less than 0.01).

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

    PubMed

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

    2006-02-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm x 2.7 cm x -0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 x 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of -180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 x 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 x 10(-4) with the energy window of +/-10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT.

  13. The Use of Combined Single Photon Emission Computed Tomography and X-ray Computed Tomography to Assess the Fate of Inhaled Aerosol

    PubMed Central

    Conway, Joy; Majoral, Caroline; Tossici-Bolt, Livia; Katz, Ira; Caillibotte, Georges; Perchet, Diane; Pichelin, Marine; Muellinger, Bernhard; Martonen, Ted; Kroneberg, Philipp; Apiou-Sbirlea, Gabriela

    2011-01-01

    Abstract Background Gamma camera imaging is widely used to assess pulmonary aerosol deposition. Conventional planar imaging provides limited information on its regional distribution. In this study, single photon emission computed tomography (SPECT) was used to describe deposition in three dimensions (3D) and combined with X-ray computed tomography (CT) to relate this to lung anatomy. Its performance was compared to planar imaging. Methods Ten SPECT/CT studies were performed on five healthy subjects following carefully controlled inhalation of radioaerosol from a nebulizer, using a variety of inhalation regimes. The 3D spatial distribution was assessed using a central-to-peripheral ratio (C/P) normalized to lung volume and for the right lung was compared to planar C/P analysis. The deposition by airway generation was calculated for each lung and the conducting airways deposition fraction compared to 24-h clearance. Results The 3D normalized C/P ratio correlated more closely with 24-h clearance than the 2D ratio for the right lung [coefficient of variation (COV), 9% compared to 15% p < 0.05]. Analysis of regional distribution was possible for both lungs in 3D but not in 2D due to overlap of the stomach on the left lung. The mean conducting airways deposition fraction from SPECT for both lungs was not significantly different from 24-h clearance (COV 18%). Both spatial and generational measures of central deposition were significantly higher for the left than for the right lung. Conclusions Combined SPECT/CT enabled improved analysis of aerosol deposition from gamma camera imaging compared to planar imaging. 3D radionuclide imaging combined with anatomical information from CT and computer analysis is a useful approach for applications requiring regional information on deposition. PMID:21166585

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

    PubMed Central

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

    2008-01-01

    The first full single-photon emission computed tomography (SPECT) imager to exploit eight compact high-intrinsic-resolution cadmium zinc telluride (CZT) detectors, called SemiSPECT, has been completed. Each detector consists of a CZT crystal and a customized application-specific integrated circuit (ASIC). The CZT crystal is a 2.7 cm × 2.7 cm × ~ 0.2 cm slab with a continuous top electrode and a bottom electrode patterned into a 64 × 64 pixel array by photolithography. The ASIC is attached to the bottom of the CZT crystal by indium-bump bonding. A bias voltage of −180 V is applied to the continuous electrode. The eight detectors are arranged in an octagonal lead-shielded ring. Each pinhole in the eight-pinhole aperture placed at the center of the ring is matched to each individual detector array. An object is imaged onto each detector through a pinhole, and each detector is operated independently with list-mode acquisition. The imaging subject can be rotated about a vertical axis to obtain additional angular projections. The performance of SemiSPECT was characterized using 99mTc. When a 0.5 mm diameter pinhole is used, the spatial resolution on each axis is about 1.4 mm as estimated by the Fourier crosstalk matrix, which provides an algorithm-independent average resolution over the field of view. The energy resolution achieved by summing neighboring pixel signals in a 3 × 3 window is about 10% full-width-at-half-maximum of the photopeak. The overall system sensitivity is about 0.5 × 10−4 with the energy window of ±10% from the photopeak. Line-phantom images are presented to visualize the spatial resolution provided by SemiSPECT, and images of bone, myocardium, and human tumor xenografts in mice demonstrate the feasibility of preclinical small-animal studies with SemiSPECT. PMID:16532954

  15. Ultrafast electrical control of a resonantly driven single photon source

    SciTech Connect

    Cao, Y.; Bennett, A. J. Ellis, D. J. P.; Shields, A. J.; Farrer, I.; Ritchie, D. A.

    2014-08-04

    We demonstrate generation of a pulsed stream of electrically triggered single photons in resonance fluorescence, by applying high frequency electrical pulses to a single quantum dot in a p-i-n diode under resonant laser excitation. Single photon emission was verified, with the probability of multiple photon emission reduced to 2.8%. We show that despite the presence of charge noise in the emission spectrum of the dot, resonant excitation acts as a “filter” to generate narrow bandwidth photons.

  16. Single-photon electroluminescence for on-chip quantum networks

    NASA Astrophysics Data System (ADS)

    Bentham, C.; Hallett, D.; Prtljaga, N.; Royall, B.; Vaitiekus, D.; Coles, R. J.; Clarke, E.; Fox, A. M.; Skolnick, M. S.; Itskevich, I. E.; Wilson, L. R.

    2016-10-01

    An electrically driven single-photon source has been monolithically integrated with nano-photonic circuitry. Electroluminescent emission from a single InAs/GaAs quantum dot (QD) is channelled through a suspended nanobeam waveguide. The emission line has a linewidth of below 6 μeV, demonstrating the ability to have a high coherence, electrically driven, waveguide coupled QD source. The single-photon nature of the emission is verified by g ( 2 ) ( τ ) correlation measurements. Moreover, in a cross-correlation experiment, with emission collected from the two ends of the waveguide, the emission and propagation of single photons from the same QD is confirmed. This work provides the basis for the development of electrically driven on-chip single-photon sources, which can be readily coupled to waveguide filters, directional couplers, phase shifters, and other elements of quantum photonic networks.

  17. Utility of left lateral supine position for myocardial perfusion single-photon emission computed tomography compared with other methods of correcting inferior wall attenuation.

    PubMed

    Sayman, Haluk B; Kanmaz, Bedii; Uslu, Ilhami; Al-Nahhas, Adil; Cuocolo, Alberto; Carril, José M; Cinaral, Ferahnaz; El-Refaei, Sherif; Senocak, Mustafa

    2015-03-01

    Single-photon emission computed tomography (SPECT) myocardial perfusion imaging is an accepted method for reflecting the pathophysiological significance of lesions detected by coronary angiography. However, it has an inherent drawback in terms of false-positive perfusion defects for the inferior myocardial wall. To overcome this problem, different acquisition techniques have been proposed, including the computed tomographic-based attenuation correction method. In this respect, a new imaging technique, left supine lateral position SPECT myocardial perfusion imaging with technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI), has been proposed to eliminate this problem and its value has been investigated in this report. Sixty-two patients were prospectively and randomly enrolled in this study. They underwent Tc-99m MIBI SPECT in the supine, prone, left lateral, and sitting positions after an adequate stress test on the same day.The presence and extent of defects on stress images were noted in the supine image data set for the 11 myocardial segments, which were then labeled as 1 or 0 if a defect was present or absent, respectively. This evaluation sequence was repeated in all other image data sets. When defects persisted in other scan positions it was regarded as true positive, and when they were resolved they were regarded as false positive. By this means, the percentages of resolving perfusion defects by that imaging position were calculated for each observer per positional pair under comparison. From six interpretations carried out by the nuclear medicine physicians, 6×11×3=198 four-fold tables in 11 segments were analyzed for discrepancies between position pairs. In 31 of 33 discrepant interpretations, defects observed in any of the other positions were resolved in the lateral position. Only in two evaluations of one observer were the discrepancies against lateral positioning for the anterior wall. If the inferior wall was considered alone, it was clearly

  18. Ten-Year Outcomes: The Clinical Utility of Single Photon Emission Computed Tomography/Computed Tomography Capromab Pendetide (Prostascint) in a Cohort Diagnosed With Localized Prostate Cancer

    SciTech Connect

    Ellis, Rodney J.; Kaminsky, Deborah A.; Zhou, Esther H.; Fu, Pingfu; Chen, Wei-Dong; Faulhaber, Peter F.; Bodner, Donald

    2011-09-01

    Purpose: To evaluate the clinical utility of capromab pendetide imaging with single photon emission computed tomography coregistration with computed tomography (SPECT/CT) in primary prostate cancer (CaP) for pretreatment prognostic staging and localization of biologic target volumes (BTV) for individualized image-guided radiotherapy dose escalation (IGRT-DE). Methods and Materials: Patients consecutively presenting for primary radiotherapy (February 1997 to December 2002), having a clinical diagnosis of localized CaP, were evaluated for tumor stage using conventional staging and SPECT/CT (N = 239). Distant metastatic uptake (mets) were identified by SPECT/CT in 22 (9.2%). None of the suspected mets could be clinically confirmed. Thus, all subjects were followed without alteration in disease management. The SPECT/CT pelvic images defined BTV for IGRT-DE (+150% brachytherapy dose) without (n = 150) or with (n = 89) external radiation of 45 Gy. The National Comprehensive Cancer Network criteria defined risk groups (RG). The median survivor follow-up was 7 years. Biochemical disease-free survival (bDFS) was reported by clinical nadir +2 ng/mL (CN+2) criteria. Statistical analyses included Kaplan-Meier, multivariate analysis, and Concordance-index models. Results: At 10-year analyses, overall survival was 84.8% and bDFS was 84.6%. With stratification by RG, CN+2 bDFS was 93.5% for the low-RG (n = 116), 78.7% for the intermediate-RG (n = 94), and 68.8% for the high-RG (n = 29), p = 0.0002. With stratification by pretreatment SPECT/CT findings, bDFS was 65.5% in patients with suspected mets (n = 22) vs. 86.6% in patients with only localized uptake (n = 217), p = 0.0014. CaP disease-specific survival (DSS) was 97.7% for the cohort. With stratification by SPECT/CT findings, DSS was 86.4% (with suspected mets) vs. 99.0% (localized only), p = 0.0001. Using multivariate analysis, the DSS hazard ratio for SPECT/CT findings (mets vs. localized) was 3.58 (p = 0.0026). Concordance

  19. Correlative 99mTc-Labeled Tropane Derivative Single Photon Emission Computer Tomography and Clinical Assessment in the Staging of Parkinson Disease

    PubMed Central

    Shinto, Ajit S.; Antony, Joppy; Kamaleshwaran, Koramadai; Vijayan, Krishnan; Selvan, Arul; Korde, Aruna; Kameshwaran, Mythili; Samuel, Grace

    2014-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by a selective loss of dopamine in the striatum. Problems remain in the accurate diagnosis of PD. The diagnosis of idiopathic PD is based on the interpretation of clinical signs and symptoms could be incorrect at the time of initial presentation. In vivo imaging of the dopaminergic system has the potential to improve the diagnosis of PD in its early stages. The imaging of dopamine transporter (DAT) with 99mTc-labeled tropane derivative (TRODAT-1) single photon emission computer tomography/computer tomography (SPECT/CT) has been proposed to be a valuable and feasible means of assessment of the integrity of dopamine neurons. The purpose of this study was to investigate the potential usefulness of 99mTc-TRODAT-1 imaging in the evaluation of patients with PD and classify into different stages of the disease. SPECT imaging with 99mTc-TRODAT-1 was conducted in 16 consecutive PD patients (9 men; 7 women) and in 6 age matched healthy volunteers (4 men; 2 women). The images were obtained 3 h after the intra-venous injection of the tracer. Specific uptake in the striatum and its sub-regions, including the putamen and caudate nucleus was calculated and the ratios of specific striatal binding to nonspecific occipital binding were calculated. ANOVA with Dunnett C post-hoc analysis was conducted using SPSS 20. A stepwise reduction in specific striatal uptake of 99mTc-TRODAT-1 with increasing disease severity between healthy control versus Stage I versus Stage II versus Stage III was found in PD patients (i.e., 3.77 vs. 2.56 vs. 1.57 vs. 0.63, P < 0.05). The changes were magnified by measurement of specific putaminal uptake (1.43 vs. 0.79 vs. 0.54 vs. 0.19, P < 0.05) and specific caudate uptake (1.90 vs. 1.47 vs. 0.73 vs. 0.27, P < 0.05). No remarkable adverse reactions were found in either healthy volunteers or PD patients during or after imaging. 99mTc-TRODAT-1 is accurate and widely available

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

    PubMed

    Sadauskiene, Egle; Zakarkaite, Diana; Ryliskyte, Ligita; Celutkiene, Jelena; Rudys, Alfredas; Aidietiene, Sigita; Laucevicius, Aleksandras

    2011-05-28

    The study was designed to evaluate whether the preserved coronary flow reserve (CFR) 72 hours after reperfused acute myocardial infarction (AMI) is associated with less microvascular dysfunction and is predictive of left ventricular (LV) functional recovery and the final infarct size at follow-up. In our study, CFR was assessed by transthoracic Doppler echocardiography (TDE) in 44 patients after the successful percutaneous coronary intervention during the acute AMI phase. CFR was correlated with contractile reserve assessed by low-dose dobutamine echocardiography and with the total perfusion defect measured by single-photon emission computed tomography 72 hours after reperfusion and at 5 months follow-up. The ROC analysis was performed to determine test sensitivity and specificity based on CFR. Categorical data were compared by an χ² analysis, continuous variables were analysed with the independent Student's t test. In order to analyse correlation between CFR and the parameters of LV function and perfusion, the Pearson correlation analysis was conducted. The linear regression analysis was used to assess the relationship between CFR and myocardial contractility as well as the final infarct size. We estimated the CFR cut-off value of 1.75 as providing the maximal accuracy to distinguish between patients with preserved and impaired CFR during the acute AMI phase (sensitivity 91.7%, specificity 75%). Wall motion score index was better in the subgroup with preserved CFR as compared to the subgroup with reduced CFR: 1.74 (0.29) vs. 1.89 (0.17) (p < 0.001) during the acute phase and 1.47 (0.30) vs. 1.81 (0.20) (p < 0.001) at follow-up, respectively. LV ejection fraction was 47.78% (8.99) in preserved CFR group vs. 40.79% (7.25) in impaired CFR group (p = 0.007) 72 hours after reperfusion and 49.78% (8.70) vs. 40.36% (7.90) (p = 0.001) after 5 months at follow-up, respectively. The final infarct size was smaller in patients with preserved as compared to patients with

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

    PubMed Central

    2011-01-01

    Background The study was designed to evaluate whether the preserved coronary flow reserve (CFR) 72 hours after reperfused acute myocardial infarction (AMI) is associated with less microvascular dysfunction and is predictive of left ventricular (LV) functional recovery and the final infarct size at follow-up. Methods In our study, CFR was assessed by transthoracic Doppler echocardiography (TDE) in 44 patients after the successful percutaneous coronary intervention during the acute AMI phase. CFR was correlated with contractile reserve assessed by low-dose dobutamine echocardiography and with the total perfusion defect measured by single-photon emission computed tomography 72 hours after reperfusion and at 5 months follow-up. The ROC analysis was performed to determine test sensitivity and specificity based on CFR. Categorical data were compared by an χ2 analysis, continuous variables were analysed with the independent Student's t test. In order to analyse correlation between CFR and the parameters of LV function and perfusion, the Pearson correlation analysis was conducted. The linear regression analysis was used to assess the relationship between CFR and myocardial contractility as well as the final infarct size. Results We estimated the CFR cut-off value of 1.75 as providing the maximal accuracy to distinguish between patients with preserved and impaired CFR during the acute AMI phase (sensitivity 91.7%, specificity 75%). Wall motion score index was better in the subgroup with preserved CFR as compared to the subgroup with reduced CFR: 1.74 (0.29) vs. 1.89 (0.17) (p < 0.001) during the acute phase and 1.47 (0.30) vs. 1.81 (0.20) (p < 0.001) at follow-up, respectively. LV ejection fraction was 47.78% (8.99) in preserved CFR group vs. 40.79% (7.25) in impaired CFR group (p = 0.007) 72 hours after reperfusion and 49.78% (8.70) vs. 40.36% (7.90) (p = 0.001) after 5 months at follow-up, respectively. The final infarct size was smaller in patients with preserved as

  2. Aerosol Delivery with Two Nebulizers Through High-Flow Nasal Cannula: A Randomized Cross-Over Single-Photon Emission Computed Tomography-Computed Tomography Study.

    PubMed

    Dugernier, Jonathan; Hesse, Michel; Jumetz, Thibaud; Bialais, Emilie; Roeseler, Jean; Depoortere, Virginie; Michotte, Jean-Bernard; Wittebole, Xavier; Ehrmann, Stephan; Laterre, Pierre-François; Jamar, François; Reychler, Gregory

    2017-10-01

    High-flow nasal cannula use is developing in ICUs. The aim of this study was to compare aerosol efficiency by using two nebulizers through a high-flow nasal cannula: the most commonly used jet nebulizer (JN) and a more efficient vibrating-mesh nebulizer (VN). Aerosol delivery of diethylenetriaminepentaacetic acid labeled with technetium-99m (4 mCi/4 mL) to the lungs by using a VN (Aerogen Solo(®); Aerogen Ltd., Galway, Ireland) and a constant-output JN (Opti-Mist Plus Nebulizer(®); ConvaTec, Bridgewater, NJ) through a high-flow nasal cannula (Optiflow(®); Fisher & Paykel, New Zealand) was compared in six healthy subjects. Flow rate was set at 30 L/min through the heated humidified circuit. Pulmonary and extrapulmonary deposition was measured by single-photon emission computed tomography combined with a low-dose computed tomographic scan and by planar scintigraphy. Lung deposition was only 3.6 (2.1-4.4) and 1 (0.7-2)% of the nominal dose with the VN and the JN, respectively (p < 0.05). The JN showed higher retained doses than the VN. However, both nebulizers were associated with substantial deposition in the single limb circuit, the humidification chamber, and the nasal cannula [58.2 (51.6-61.6)% of the nominal dose with the VN versus 19.2 (15.8-22.9)% of the nominal dose with the JN, p < 0.05] and in the upper respiratory tract [17.6 (13.4-27.9)% of the nominal dose with the VN and 8.6 (6.0-11.0)% of the nominal dose with the JN, p < 0.05], especially in the nasal cavity. In the specific conditions of the study, pulmonary drug delivery through the high-flow nasal cannula is about 1%-4% of the initial amount of drugs placed in the nebulizer, despite the higher efficiency of the VN as compared with the JN.

  3. Evaluation of external beam hardening filters on image quality of computed tomography and single photon emission computed tomography/computed tomography.

    PubMed

    Rana, Nivedita; Rawat, Dinesh; Parmar, Madan; Dhawan, Devinder Kumar; Bhati, Ashok Kumar; Mittal, Bhagwant Rai

    2015-01-01

    This study was undertaken to evaluate the effect of external metal filters on the image quality of computed tomography (CT) and single photon emission computed tomography (SPECT)/CT images. Images of Jaszack phantom filled with water and containing iodine contrast filled syringes were acquired using CT (120 kV, 2.5 mA) component of SPECT/CT system, ensuring fixation of filter on X-ray collimator. Different thickness of filters of Al and Cu (1 mm, 2 mm, 3 mm, and 4 mm) and filter combinations Cu 1 mm, Cu 2 mm, Cu 3 mm each in combination with Al (1 mm, 2 mm, 3 mm, and 4 mm), respectively, were used. All image sets were visually analyzed for streak artifacts and contrast to noise ratio (CNR) was derived. Similar acquisition was done using Philips CT quality control (QC) phantom and CNR were calculated for its lexan, perspex, and teflon inserts. Attenuation corrected SPECT/CT images of Jaszack phantom filled with 444-555 MBq (12-15 mCi) of (99m)Tc were obtained by applying attenuation correction map generated by hardened X-ray beam for different filter combination, on SPECT data. Uniformity, root mean square (rms) and contrast were calculated in all image sets. Less streak artifacts at iodine water interface were observed in images acquired using external filters as compared to those without a filter. CNR for syringes, spheres, and inserts of Philips CT QC phantom was almost similar to Al 2 mm, Al 3 mm, and without the use of filters. CNR decreased with increasing copper thickness and other filter combinations. Uniformity and rms were lower, and value of contrast was higher for SPECT/CT images when CT was acquired with Al 2 mm and 3 mm filter than for images acquired without a filter. The study suggests that for Infinia Hawkeye 4, SPECT/CT system, Al 2 mm, and 3 mm are the optimum filters for improving image quality of SPECT/CT images of Jaszack or Philips CT QC phantom keeping other parameters of CT constant.

  4. Preliminary clinical study in patients with hemispatial neglect after stroke by neglect test battery and 99mTc-ECD single-photon emission computed tomography.

    PubMed

    Yin, Yafu; Li, Xuena; Li, Yaming; Gu, Hui; Han, Chunqi; Liu, Hao

    2009-05-01

    To explore the presence, clinical characteristics, anatomical foci in image and mechanism of hemispatial neglect (HSN), neglect test battery and single-photon emission computed tomography (SPECT) regional cerebral blood flow (rCBF) imaging were performed on patients with stroke. Thirty dextromanual patients who were diagnosed as having unilateral stroke clinically were recruited. A neglect test battery including line bisection test, star cancellation test and drawing test was performed on the subjects. The severity of neglect was measured on neglect tests. The lowest rCBF, the range with decreased rCBF, number of the foci with decreased rCBF, the flow deficit size and the total number of pixels in the foci were measured on SPECT rCBF imaging. Twenty-five patients were diagnosed as having HSN by the neglect test battery. Contralateral neglect (CN) and ipsilateral neglect (IN) were observed in both right and left hemisphere strokes. On SPECT imaging, the patients with neglect had decreased rCBF in the frontal cortex most often; followed by the parietal, occipital and temporal cortices; and basal ganglia and thalamus in some cases. The patients who had two or more regions damaged showed neglect more often and severity. The correlation coefficients between rCBF in the foci, the decreased percentage of rCBF of the foci and the severity of neglect were -0.119 (P>.05) and 0.221 (P>.05). The correlation coefficients between the range, number of foci, the flow deficit size, the total number of pixels of the foci and the severity of neglect were 0.537 (P<.05), 0.493 (P<.05), 0.561 (P<.05), 0.466 (P<.05), respectively. No difference between CN and IN on SPECT images reached statistical significance. The severity of neglect did not correlate with rCBF and the decreased percentage of rCBF in the foci, while it was significantly correlated with the range, number of foci, the flow deficit size and the total numbers of pixels of the foci significantly. And the patients with CN and

  5. Assessment of the relationship between stenosis severity and distribution of coronary artery stenoses on multislice computed tomographic angiography and myocardial ischemia detected by single photon emission computed tomography

    PubMed Central

    Tamarappoo, Balaji K.; Gutstein, Ariel; Cheng, Victor Y.; Nakazato, Ryo; Gransar, Heidi; Dey, Damini; Thomson, Louise E. J.; Hayes, Sean W.; Friedman, John D.; Germano, Guido; Slomka, Piotr J.

    2010-01-01

    Background The relationship between luminal stenosis measured by coronary CT angiography (CCTA) and severity of stress-induced ischemia seen on single photon emission computed tomographic myocardial perfusion imaging (SPECT-MPI) is not clearly defined. We sought to evaluate the relationship between stenosis severity assessed by CCTA and ischemia on SPECT-MPI. Methods and Results ECG-gated CCTA (64 slice dual source CT) and SPECT-MPI were performed within 6 months in 292 patients (ages 26-91, 73% male) with no prior history of coronary artery disease. Maximal coronary luminal narrowing, graded as 0, ≥25%, 50%, 70%, or 90% visual diameter reduction, was consensually assessed by two expert readers. Perfusion defect on SPECT-MPI was assessed by computer-assisted visual interpretation by an expert reader using the standard 17 segment, 5 point-scoring model (stress perfusion defect of ≥5% = abnormal). By SPECT-MPI, abnormal perfusion was seen in 46/292 patients. With increasing stenosis severity, positive predictive value (PPV) increased (42%, 51%, and 74%, P = .01) and negative predictive value was relatively unchanged (97%, 95%, and 91%) in detecting perfusion abnormalities on SPECT-MPI. In a receiver operator curve analysis, stenosis of 50% and 70% were equally effective in differentiating between the presence and absence of ischemia. In a multivariate analysis that included stenosis severity, multivessel disease, plaque composition, and presence of serial stenoses in a coronary artery, the strongest predictors of ischemia were stenosis of 50-89%, odds ratio (OR) 7.31, P = .001, stenosis ≥90%, OR 34.05, P = .0001, and serial stenosis ≥50% OR of 3.55, P = .006. Conclusions The PPV of CCTA for ischemia by SPECT-MPI rises as stenosis severity increases. Luminal stenosis ≥90% on CCTA strongly predicts ischemia, while <50% stenosis strongly predicts the absence of ischemia. Serial stenosis of ≥50% in a vessel may offer incremental value in addition

  6. The interaction of exercise ability and body mass index upon long-term outcomes among patients undergoing stress-rest perfusion single-photon emission computed tomography imaging.

    PubMed

    Uretsky, Seth; Supariwala, Azhar; Gurram, Srinivasa; Bonda, Sri Lakshmi Kala; Thota, Naganath; Bezwada, Prema; Manchireddy, Seema; Nair, Subu; Cohen, Randy; Rozanski, Alan

    2013-07-01

    The obesity paradox has been reported in several populations of patients with cardiovascular disease. Recent data have shown that physical fitness may attenuate the obesity paradox. Patients who undergo pharmacologic stress testing are known to have a higher risk of mortality than those who can exercise. The purpose of this study is to determine the interaction of obesity and exercise ability on survival among patients with a normal stress-rest single-photon emission computed tomography (SPECT). A total of 5,203 (60 ± 13 years, male 37%) patients without a history of heart disease and a normal stress-rest SPECT between the years 1995 and 2010 were included in this analysis. Body mass index categories were defined according to the World Health Organization classification: normal weight, 18.5 to 24.9 kg/m(2); overweight, 25 to 29.9 kg/m(2); and obese, ≥30 kg/m(2). Patients were divided into 3 groups based on their ability to exercise: those who reached ≥6 METs on exercise, those who attained a level of <6 METs, and those who required pharmacologic stress. Patients in each of these fitness groups were further divided into 3 subgroups based on their body mass index. There were 939 (18%) deaths during a mean follow-up of 8.1 ± 4.1 years, for an overall event rate of 2.3%/y. Both exercise to ≥6 METs and being obese were associated with lower mortality. Adjusted multivariate analysis using the obese high-fit patients as the reference showed a wide heterogeneity in annualized mortality rates according to exercise and weight status, with annualized event rates which varied from 0.6%/y in the obese subjects who were physically fit to 5.3%/y among healthy subjects who underwent pharmacologic stress testing (P < .001). Stress mode and body weight impacted long-term survival in patients with a normal stress SPECT. The benefit of being physically fit was evident in all weight groups, as was the adverse effect of being unable to exercise. However, with regard to body

  7. Long-term estrogen therapy and 5-HT(2A) receptor binding in postmenopausal women; a single photon emission tomography (SPET) study.

    PubMed

    Compton, J; Travis, M J; Norbury, R; Erlandsson, K; van Amelsvoort, T; Daly, E; Waddington, W; Matthiasson, P; Eersels, J L H; Whitehead, M; Kerwin, R W; Ell, P J; Murphy, D G M

    2008-01-01

    Variation in estrogen level is reported by some to affect brain maturation and memory. The neurobiological basis for this may include modulation of the serotonergic system. No neuroimaging studies have directly examined the effect of extended estrogen therapy (ET), on the 5-HT(2A) receptor in human brain. We investigated the effect of long-term ET on cortical 5-HT(2A) receptor availability in postmenopausal women. In a cross-sectional study, we compared cortical 5-HT(2A) receptor availability in 17 postmenopausal ERT-naive women and 17 long-term oophorectomised estrogen-users, age- and IQ-matched using single photon emission tomography and the selective 5-HT(2A) receptor ligand (123)I-5-I-R91150. Also, we used the Revised Wechsler Memory Scale to relate memory function to 5-HT(2A) receptor availability. Never-users had significantly higher 5-HT(2A) receptor availability than estrogen-users in hippocampus (1.17 vs. 1.11, respectively, p=0.02), although this did not remain significant after correction for multiple comparisons. Hippocampal 5-HT(2A) receptor availability correlated negatively with verbal and general memory and delayed recall (r=-0.45, p=0.01; r=-0.40, p=0.02; r=-0.36, p=0.04). Right superior temporal 5-HT(2A) receptor availability correlated negatively with verbal memory (r=-0.36, p=0.04). In estrogen-users, receptor availability correlated negatively with verbal and general memory (r=-0.70, p=0.002; r=-0.69, p=0.002); and in never-users, receptor availability negatively correlated with attention and concentration (r=-0.54, p=0.02). Long-term ET may be associated with lower 5-HT(2A) receptor availability in hippocampus. This may reflect increased activity within the serotonergic pathway leading to down-regulation of post-synaptic receptor. Also, increased availability of the 5-HT(2A) receptor in hippocampus is associated with poorer memory function.

  8. Impact of Gender on the Prognostic Value of Coronary Artery Calcium in Symptomatic Patients With Normal Single-Photon Emission Computed Tomography Myocardial Perfusion.

    PubMed

    Engbers, Elsemiek M; Timmer, Jorik R; Ottervanger, Jan Paul; Mouden, Mohamed; Knollema, Siert; Jager, Pieter L

    2016-12-01

    The coronary artery calcium (CAC) score provides independent prognostic value on top of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). We sought to determine whether the prognostic value of the CAC score in patients with normal SPECT MPI is gender specific. We studied 3,705 consecutive symptomatic patients without a history of coronary artery disease with normal SPECT MPI. All patients underwent concomitant CAC scoring, which was categorized as CAC score 0, 1 to 99, 100 to 399, 400 to 999, or ≥1,000. Major adverse cardiac events were defined as revascularization, nonfatal myocardial infarction, or all-cause mortality. The median CAC score was 9 in women (interquartile range 0 to 113) and 47 in men (interquartile range 1 to 307, p <0.001). The annual event rate was lower in women than in men (1.6% and 2.7%, respectively, p <0.001). When stratified by CAC score, annual event rates were similar (for women and men, respectively: CAC score 0, 0.6% and 0.5%, p = 0.95; CAC score 1 to 99, 0.9% and 1.2%, p = 0.45; CAC score 100 to 399, 2.7% and 3.8%, p = 0.23; CAC score 400 to 999, 3.8% and 5.3%, p = 0.34; CAC score ≥1,000, 8.4% and 8.7%, p = 0.99). The CAC score was an independent predictor of major adverse cardiac events in both genders (CAC score ≥1,000: hazard ratio for women 8.5, 95% confidence interval 4.0 to 18.1; hazard ratio for men 14.8, 95% confidence interval 5.3 to 41.1). In conclusion, risk for events is similar for both genders when stratified by CAC score, wherein a high CAC score carries a high risk for events despite normal SPECT MPI. Our findings do not reveal a gender-specific prognostic value of the CAC score.

  9. The Incremental Prognostic Value of Cardiac Computed Tomography in Comparison with Single-Photon Emission Computed Tomography in Patients with Suspected Coronary Artery Disease

    PubMed Central

    Lee, Heesun; Yoon, Yeonyee E.; Park, Jun-Bean; Kim, Hack-Lyoung; Park, Hyo Eun; Lee, Seung-Pyo; Kim, Hyung-Kwan; Choi, Su-Yeon; Kim, Yong-Jin; Cho, Goo-Yeong; Zo, Joo-Hee; Sohn, Dae-Won

    2016-01-01

    Background Coronary computed tomographic angiography (CCTA) facilitates comprehensive evaluation of coronary artery disease (CAD), including plaque characterization, and can provide additive diagnostic value to single-photon emission computed tomography (SPECT). However, data regarding the incremental prognostic value of CCTA to SPECT remain sparse. We evaluated the independent and incremental prognostic value of CCTA, as compared with clinical risk factors and SPECT. Materials and methods A total of 1,077 patients with suspected CAD who underwent both SPECT and cardiac CT between 2004 and 2012 were enrolled retrospectively. Presence of reversible or fixed perfusion defect (PD) and summed stress score were evaluated on SPECT. Presence, extent of coronary atherosclerosis and diameter stenosis (DS) were evaluated on CCTA. Plaque composition was categorized as non-calcified, mixed, or calcified according to the volume of calcified component (>130 Hounsfield Units). Patients were followed up for the occurrence of adverse cardiac events including cardiac death, non-fatal myocardial infarction, unstable angina, and late revascularization (>90 days after imaging studies). Results During follow-up (median 23 months), adverse cardiac events were observed in 71 patients (6.6%). When adjusted for clinical risk factors and SPECT findings, the presence of any coronary plaque, any plaque in ≥3 segments, coronary artery calcium score (CACS) ≥400, a plaque ≥50% DS, presence of non-calcified plaque (NCP) or mixed plaque (MP), and NCP/MP in ≥2 segments were independent predictors of adverse cardiac events; however, the presence of calcified plaque (CP) was not. Conventional CCTA findings, including CACS ≥400 and a plaque ≥50% DS, demonstrated incremental prognostic value over clinical risk factors and SPECT (χ² 54.19 to 101.03; p <0.001). Addition of NCP/MP in ≥2 segments resulted in further significantly improved prediction (χ² 101.03 to 113.29; p <0

  10. Micro-single-photon emission computed tomography image acquisition and quantification of sodium-iodide symporter-mediated radionuclide accumulation in mouse thyroid and salivary glands.

    PubMed

    Brandt, Michael P; Kloos, Richard T; Shen, Daniel H; Zhang, Xiaoli; Liu, Yu-Yu; Jhiang, Sissy M

    2012-06-01

    Micro-single-photon emission computed tomography (SPECT) provides a noninvasive way to evaluate the effects of genetic and/or pharmacological modulation on sodium-iodide symporter (NIS)-mediated radionuclide accumulation in mouse thyroid and salivary glands. However, parameters affecting image acquisition and analysis of mouse thyroids and salivary glands have not been thoroughly investigated. In this study, we investigated the effects of region-of-interest (ROI) selection, collimation, scan time, and imaging orbit on image acquisition and quantification of thyroidal and salivary radionuclide accumulation in mice. The effects of data window minima and maxima on thyroidal and salivary ROI selection using a visual boundary method were examined in SPECT images acquired from mice injected with (123)I NaI. The effects of collimation, scan time, and imaging orbit on counting linearity and signal intensity were investigated using phantoms filled with various activities of (123)I NaI or Tc-99m pertechnetate. Spatial resolution of target organs in whole-animal images was compared between circular orbit with parallel-hole collimation and spiral orbit with five-pinhole collimation. Lastly, the inter-experimental variability of the same mouse scanned multiple times was compared with the intra-experimental variability among different mice scanned at the same time. Thyroid ROI was separated from salivary glands by empirically increasing the data window maxima. Counting linearity within the range of 0.5-14.2 μCi was validated by phantom imaging using single- or multiple-pinhole collimators with circular or spiral imaging orbit. Scanning time could be shortened to 15 minutes per mouse without compromising counting linearity despite proportionally decreased signal intensity. Whole-animal imaging using a spiral orbit with five-pinhole collimators achieved a high spatial resolution and counting linearity. Finally, the extent of inter-experimental variability of NIS

  11. Evaluation of external beam hardening filters on image quality of computed tomography and single photon emission computed tomography/computed tomography

    PubMed Central

    Rana, Nivedita; Rawat, Dinesh; Parmar, Madan; Dhawan, Devinder Kumar; Bhati, Ashok Kumar; Mittal, Bhagwant Rai

    2015-01-01

    This study was undertaken to evaluate the effect of external metal filters on the image quality of computed tomography (CT) and single photon emission computed tomography (SPECT)/CT images. Images of Jaszack phantom filled with water and containing iodine contrast filled syringes were acquired using CT (120 kV, 2.5 mA) component of SPECT/CT system, ensuring fixation of filter on X-ray collimator. Different thickness of filters of Al and Cu (1 mm, 2 mm, 3 mm, and 4 mm) and filter combinations Cu 1 mm, Cu 2 mm, Cu 3 mm each in combination with Al (1 mm, 2 mm, 3 mm, and 4 mm), respectively, were used. All image sets were visually analyzed for streak artifacts and contrast to noise ratio (CNR) was derived. Similar acquisition was done using Philips CT quality control (QC) phantom and CNR were calculated for its lexan, perspex, and teflon inserts. Attenuation corrected SPECT/CT images of Jaszack phantom filled with 444–555 MBq (12–15 mCi) of 99mTc were obtained by applying attenuation correction map generated by hardened X-ray beam for different filter combination, on SPECT data. Uniformity, root mean square (rms) and contrast were calculated in all image sets. Less streak artifacts at iodine water interface were observed in images acquired using external filters as compared to those without a filter. CNR for syringes, spheres, and inserts of Philips CT QC phantom was almost similar to Al 2 mm, Al 3 mm, and without the use of filters. CNR decreased with increasing copper thickness and other filter combinations. Uniformity and rms were lower, and value of contrast was higher for SPECT/CT images when CT was acquired with Al 2 mm and 3 mm filter than for images acquired without a filter. The study suggests that for Infinia Hawkeye 4, SPECT/CT system, Al 2 mm, and 3 mm are the optimum filters for improving image quality of SPECT/CT images of Jaszack or Philips CT QC phantom keeping other parameters of CT constant. PMID:26865755

  12. Cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary heart disease (CE-MARC): a prospective trial

    PubMed Central

    Greenwood, John P; Maredia, Neil; Younger, John F; Brown, Julia M; Nixon, Jane; Everett, Colin C; Bijsterveld, Petra; Ridgway, John P; Radjenovic, Aleksandra; Dickinson, Catherine J; Ball, Stephen G; Plein, Sven

    2012-01-01

    Summary Background In patients with suspected coronary heart disease, single-photon emission computed tomography (SPECT) is the most widely used test for the assessment of myocardial ischaemia, but its diagnostic accuracy is reported to be variable and it exposes patients to ionising radiation. The aim of this study was to establish the diagnostic accuracy of a multiparametric cardiovascular magnetic resonance (CMR) protocol with x-ray coronary angiography as the reference standard, and to compare CMR with SPECT, in patients with suspected coronary heart disease. Methods In this prospective trial patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR, SPECT, and invasive x-ray coronary angiography. CMR consisted of rest and adenosine stress perfusion, cine imaging, late gadolinium enhancement, and MR coronary angiography. Gated adenosine stress and rest SPECT used 99mTc tetrofosmin. The primary outcome was diagnostic accuracy of CMR. This trial is registered at controlled-trials.com, number ISRCTN77246133. Findings In the 752 recruited patients, 39% had significant CHD as identified by x-ray angiography. For multiparametric CMR the sensitivity was 86·5% (95% CI 81·8–90·1), specificity 83·4% (79·5–86·7), positive predictive value 77·2%, (72·1–81·6) and negative predictive value 90·5% (87·1–93·0). The sensitivity of SPECT was 66·5% (95% CI 60·4–72·1), specificity 82·6% (78·5–86·1), positive predictive value 71·4% (65·3–76·9), and negative predictive value 79·1% (74·8–82·8). The sensitivity and negative predictive value of CMR and SPECT differed significantly (p<0·0001 for both) but specificity and positive predictive value did not (p=0·916 and p=0·061, respectively). Interpretation CE-MARC is the largest, prospective, real world evaluation of CMR and has established CMR's high diagnostic accuracy in coronary heart disease and CMR's superiority over SPECT. It should be

  13. Correlation of Tc-99 m ethyl cysteinate dimer single-photon emission computed tomography and clinical presentations in patients with low cobalamin status.

    PubMed

    Tu, Min-Chien; Lo, Chung-Ping; Chen, Ching-Yuan; Huang, Ching-Feng

    2015-12-03

    Cobalamin (Cbl) deficiency has been associated with various neuropsychiatric symptoms of different severities. While some studies dedicated in structural neuroimaging credibly address negative impact of low Cbl status, functional imaging reports are limited. We herein retrospectively review the correlation of Tc-99 m ethyl cysteinate dimer single-photon emission computed tomography (Tc-99 m-ECD SPECT) and clinical presentations among patients with low serum cobalamin (Cbl) status (<250 pg/ml). Twelve symptomatic patients with low serum Cbl status were enrolled. Clinical presentations, Tc-99 m-ECD SPECT, and neuropsychological tests were reviewed. Dysexecutive syndrome (67 %), forgetfulness (50 %), attention deficits (42 %), and sleep disorders (33 %) constituted the major clinical presentations. All patients (100 %) had temporal hypoperfusion on the Tc-99 m-ECD SPECT. Five patients (42 %) had hypoperfusion restricted within temporal regions and deep nuclei; seven patients (58 %) had additional frontal hypoperfusion. In patients with hypoperfusion restricted within temporal regions and deep nuclei, psychiatric symptoms with spared cognition were their main presentations. Among patients with additional frontal hypoperfusion, six of seven patients (86 %) showed impaired cognitive performances (two of them were diagnosed as having dementia). Among ten patients who finished neuropsychological tests, abstract thinking (70 %) was the most commonly affected, followed by verbal fluency (60 %), short-term memory (50 %), and attention (50 %). Anxiety and sleep problems were the major clinically remarkable psychiatric features (33 % both). Four Tc-99 m-ECD SPECT follow-up studies were available; the degree and extent of signal reversal correlated with cognitive changes after Cbl replacement therapy. Our TC-99 m-ECD SPECT observations provide pivotal information of neurobiological changes within basal ganglia and fronto-temporal regions in conjunction with disease severity

  14. Significance of functional hepatic resection rate calculated using 3D CT/99mTc-galactosyl human serum albumin single-photon emission computed tomography fusion imaging

    PubMed Central

    Tsuruga, Yosuke; Kamiyama, Toshiya; Kamachi, Hirofumi; Shimada, Shingo; Wakayama, Kenji; Orimo, Tatsuya; Kakisaka, Tatsuhiko; Yokoo, Hideki; Taketomi, Akinobu

    2016-01-01

    AIM: To evaluate the usefulness of the functional hepatic resection rate (FHRR) calculated using 3D computed tomography (CT)/99mTc-galactosyl-human serum albumin (GSA) single-photon emission computed tomography (SPECT) fusion imaging for surgical decision making. METHODS: We enrolled 57 patients who underwent bi- or trisectionectomy at our institution between October 2013 and March 2015. Of these, 26 patients presented with hepatocellular carcinoma, 12 with hilar cholangiocarcinoma, six with intrahepatic cholangiocarcinoma, four with liver metastasis, and nine with other diseases. All patients preoperatively underwent three-phase dynamic multidetector CT and 99mTc-GSA scintigraphy. We compared the parenchymal hepatic resection rate (PHRR) with the FHRR, which was defined as the resection volume counts per total liver volume counts on 3D CT/99mTc-GSA SPECT fusion images. RESULTS: In total, 50 patients underwent bisectionectomy and seven underwent trisectionectomy. Biliary reconstruction was performed in 15 patients, including hepatopancreatoduodenectomy in two. FHRR and PHRR were 38.6 ± 19.9 and 44.5 ± 16.0, respectively; FHRR was strongly correlated with PHRR. The regression coefficient for FHRR on PHRR was 1.16 (P < 0.0001). The ratio of FHRR to PHRR for patients with preoperative therapies (transcatheter arterial chemoembolization, radiation, radiofrequency ablation, etc.), large tumors with a volume of > 1000 mL, and/or macroscopic vascular invasion was significantly smaller than that for patients without these factors (0.73 ± 0.19 vs 0.82 ± 0.18, P < 0.05). Postoperative hyperbilirubinemia was observed in six patients. Major morbidities (Clavien-Dindo grade ≥ 3) occurred in 17 patients (29.8%). There was no case of surgery-related death. CONCLUSION: Our results suggest that FHRR is an important deciding factor for major hepatectomy, because FHRR and PHRR may be discrepant owing to insufficient hepatic inflow and congestion in patients with preoperative

  15. Cerebral hemodynamic disturbance in dural arteriovenous fistula with retrograde leptomeningeal venous drainage: a prospective study using (123)I-iodoamphetamine single photon emission computed tomography.

    PubMed

    Kanemaru, Kazuya; Kinouchi, Hiroyuki; Yoshioka, Hideyuki; Yagi, Takashi; Wakai, Takuma; Hashimoto, Koji; Fukumoto, Yuichiro; Umeda, Takako; Onishi, Hiroshi; Nishiyama, Yoshihisa; Horikoshi, Toru

    2015-07-01

    The severity of cerebral hemodynamic disturbance caused by retrograde leptomeningeal venous drainage (RLVD) of a dural arteriovenous fistula (dAVF) is related to neurological morbidity and unfavorable outcome. However, the cerebral hemodynamics of this disorder have not been elucidated well. The aim of this study was to assess the relationship between the cerebral venous congestive encephalopathy represented as a high-intensity area (HIA) on T2-weighted MR images and the cerebral hemodynamics examined by (123)I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT), as well as the predictive value of (123)I-IMP SPECT for the development and reversibility of venous congestion encephalopathy. Based on the pre- and posttreatment T2 HIAs associated with venous congestion encephalopathy, patients were divided into 3 groups: a normal group, an edema group, and an infarction group. The regional cerebral blood flow (rCBF) at the region with RLVD was analyzed by (123)I-IMP SPECT, and the results were compared among the groups. There were 11, 6, and 3 patients in the normal, edema, and infarction groups, respectively. No patients in the normal group showed any symptoms related to venous congestion. In contrast, all patients in the edema and infarction groups developed neurological symptoms. The rCBF in the edema group was significantly lower than that in the normal group, and significantly higher than that in the infarction group. The cerebral vascular reactivity (CVR) of the infarction group was significantly lower than that of the normal and edema groups. After treatment, the neurological signs disappeared in the edema group, but only partial improvement was seen in the infarction group. The rCBF also significantly increased in the normal and edema groups, but not in the infarction group. Quantitative rCBF measurement is useful for evaluating hemodynamic disturbance in dAVF with RLVD. The reduction of rCBF was strongly correlated with the severity of

  16. Accuracy of Dual Phase Single-Photon Emission Computed Tomography/Computed Tomography in Primary Hyperparathyroidism: Correlation With Serum Parathyroid Hormone Levels.

    PubMed

    Koberstein, Wade; Fung, Christopher; Romaniuk, Kristy; Abele, Jonathan T

    2016-05-01

    The objectives of this study were: 1) to determine the accuracy of dual-phase (99m)Tc -methoxyisobutylisonitrile (MIBI) with single-photon emission computed tomography/computed tomography (SPECT/CT) for the preoperative localization of parathyroid adenomas in the setting of primary hyperparathyroidism; 2) to determine the accuracy of localization for ectopic glands; and 3) to assess the relationship between accuracy and serum parathyroid hormone (PTH) levels. Eighty-eight patients who underwent (99m)Tc-MIBI SPECT/CT imaging for primary hyperparathyroidism at our institution over a 27-month period were retrospectively assessed. The preoperative SPECT/CT results were compared to intraoperative findings (within 1 year of imaging). The relationship between serum PTH level (within 3 months) and SPECT/CT accuracy was then evaluated. Accuracy indices for the retrothyroid subgroup were sensitivity 86.7%, specificity 96.4%, positive predictive value 98.1%, negative predictive value 77.1%, and accuracy 89.8%. Accuracy indices for ectopic parathyroid adenomas were sensitivity 81.5%, specificity 100%, positive predictive value 100%, negative predictive value 92.4%, and accuracy 94.3%. For the overall group, SPECT/CT demonstrated a sensitivity of 85.1% and a PPV of 98.7%. SPECT/CT correctly identified the abnormal parathyroid gland in 60% of patients with a normal serum PTH (<6.9 pmol/L), 73% between 6.9-9.9 pmol/L, 86% between 10.0-14.9 pmol/L, 100% between 15.0-19.9 pmol/L, 88% between 20.0-24.5 pmol/L, and 100% of patients with a PTH greater than 25.0 pmol/L. Dual-phase (99m)Tc- MIBI with SPECT/CT is an accurate and reliable means to correctly localize both retrothyroid and ectopic parathyroid adenomas for the purpose of surgical planning. The accuracy of SPECT/CT increases with increasing serum PTH levels. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  17. Osseous vitality in single photon emission computed tomography/computed tomography (SPECT/CT) after balloon tibioplasty of the tibial plateau: a case series.

    PubMed

    Jentzsch, Thorsten; Fritz, Yannick; Veit-Haibach, Patrick; Schmitt, Jürgen; Sprengel, Kai; Werner, Clément M L

    2015-11-17

    The minimally invasive, balloon-assisted reduction and cement-augmented internal fixation of the tibial plateau is an innovative surgical procedure for tibial plateau fractures. The close proximity of balloons and cement to the knee joint poses a potential risk for osteonecrosis; especially in the case of thin bone lamellae. However, there are no studies about the vitality of the cement-surrounding tissue after these tibioplasties. Therefore, our goal was to assess the osseous vitality after cement-augmented balloon tibioplasty using single photon emission computed tomography/computed tomography (SPECT/CT) in a series of patients. This case series evaluated available consecutive patients, whose tibial plateau fractures were treated with balloon-assisted, cement-augmented tibioplasty and received a SPECT/CT. Primary outcome variables were osseous vitality on SPECT/CTs according to the semiquantitative tracer activity analysis. The mean uptake of eight tibial regions of interest was referenced to the mean uptake count on the same region of the contralateral leg to obtain a count ratio. Osteonecrosis was defined as a photopenic area or cold defect. Secondary variables included clinical and radiological follow-up data. Statistics were carried out in a descriptive pattern. Ten patients with a mean age of 59 years and a mean follow up of 18 months were included. Calcium phosphate (CaP) substitute bone cement was used in 60% and polymethyl methacrylate mixed with hydroxyapatite (PMMA/HA) bone cement in 40%. Normal to high SPECT/CT activity without photopenic areas were observed in all patients and the mean tracer activity ratio was four, indicating vital bone in all patients. There were no postoperative infections and only one 57 year old patient with hemineglect and CaP cement showed failed osseous consolidation. The mean Tegner and Lysholm as well as the Lysholm scores were three and 80, respectively. This novel study about cement-augmented balloon tibioplasties showed

  18. Handheld single photon emission computed tomography (handheld SPECT) navigated video-assisted thoracoscopic surgery of computer tomography-guided radioactively marked pulmonary lesions.

    PubMed

    Müller, Joachim; Putora, Paul Martin; Schneider, Tino; Zeisel, Christoph; Brutsche, Martin; Baty, Florent; Markus, Alexander; Kick, Jochen

    2016-09-01

    Radioactive marking can be a valuable extension to minimally invasive surgery. The technique has been clinically applied in procedures involving sentinel lymph nodes, parathyroidectomy as well as interventions in thoracic surgery. Improvements in equipment and techniques allow one to improve the limits. Pulmonary nodules are frequently surgically removed for diagnostic or therapeutic reasons; here video-assisted thoracoscopic surgery (VATS) is the preferred technique. VATS might be impossible with nodules that are small or located deep in the lung. In this study, we examined the clinical application and safety of employing the newly developed handheld single photon emission tomography (handheld SPECT) device in combination with CT-guided radioactive marking of pulmonary nodules. In this pilot study, 10 subjects requiring surgical resection of a pulmonary nodule were included. The technique involved CT-guided marking of the target nodule with a 20-G needle, with subsequent injection of 25-30 MBq (effective: 7-14 MBq) Tc-99m MAA (Macro Albumin Aggregate). Quality control was made with conventional SPECT-CT to confirm the correct localization and exclude possible complications related to the puncture procedure. VATS was subsequently carried out using the handheld SPECT to localize the radioactivity intraoperatively and therefore the target nodule. A 3D virtual image was superimposed on the intraoperative visual image for surgical guidance. In 9 of the 10 subjects, the radioactive application was successfully placed directly in or in the immediate vicinity of the target nodule. The average size of the involved nodules was 9 mm (range 4-15). All successfully marked nodules were subsequently completely excised (R0) using VATS. The procedure was well tolerated. An asymptomatic clinically insignificant pneumothorax occurred in 5 subjects. Two subjects were found to have non-significant discrete haemorrhage in the infiltration canal of the needle. In a single subject, the

  19. Temporal Trends of Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging in Patients With Coronary Artery Disease: A 22-Year Experience From a Tertiary Academic Medical Center.

    PubMed

    Jouni, Hayan; Askew, J Wells; Crusan, Daniel J; Miller, Todd D; Gibbons, Raymond J

    2017-07-01

    There has been a gradual decline in the prevalence of abnormal stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging studies among patients without history of coronary artery disease (CAD). The trends of SPECT studies among patients with known CAD have not been evaluated previously. We assessed the Mayo Clinic nuclear cardiology database for all stress SPECT tests performed between January 1991 and December 2012 in patients with history of CAD defined as having previous myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting. The study cohort was divided into 5 time periods: 1991 to 1995, 1996 to 2000, 2001 to 2005, 2006 to 2010, and 2011 to 2012. There were 19 373 patients with a history of CAD who underwent SPECT between 1991 and 2012 (mean age, 66.2±10.9 years; 75.4% men). Annual utilization of SPECT in these patients increased from an average of 495 tests per year in 1991 to 1995 to 1425 in 2003 and then decreased to 552 tests in 2012 without evidence for substitution with other stress modalities. Asymptomatic patients initially increased until 2006 and then decreased. Patients with typical angina decreased, whereas patients with dyspnea and atypical angina increased. High-risk SPECT tests significantly decreased, and the percentage of low-risk SPECT tests increased despite decreased SPECT utilization between 2003 and 2012. Almost 80% of all tests performed in 2012 had a low-risk summed stress score compared with 29% in 1991 (P<0.001). In Mayo Clinic, Rochester, annual SPECT utilization in patients with previous CAD increased between 1992 and 2003, but then decreased after 2003. High-risk SPECT tests declined, whereas low-risk tests increased markedly. Our results suggest that among patients with a history of CAD, SPECT was being increasingly utilized in patients with milder CAD. This trend parallels reduced utilization of other stress modalities, coronary angiography, reduced smoking, and

  20. Accuracy of Computed Tomographic Angiography and Single-Photon Emission Computed Tomography-Acquired Myocardial Perfusion Imaging for the Diagnosis of Coronary Artery Disease.

    PubMed

    Arbab-Zadeh, Armin; Di Carli, Marcelo F; Cerci, Rodrigo; George, Richard T; Chen, Marcus Y; Dewey, Marc; Niinuma, Hiroyuki; Vavere, Andrea L; Betoko, Aisha; Plotkin, Michail; Cox, Christopher; Clouse, Melvin E; Arai, Andrew E; Rochitte, Carlos E; Lima, Joao A C; Brinker, Jeffrey; Miller, Julie M

    2015-10-01

    Establishing the diagnosis of coronary artery disease (CAD) in symptomatic patients allows appropriately allocating preventative measures. Single-photon emission computed tomography (CT)-acquired myocardial perfusion imaging (SPECT-MPI) is frequently used for the evaluation of CAD, but coronary CT angiography (CTA) has emerged as a valid alternative. We compared the accuracy of SPECT-MPI and CTA for the diagnosis of CAD in 391 symptomatic patients who were prospectively enrolled in a multicenter study after clinical referral for cardiac catheterization. The area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of CTA and SPECT-MPI for identifying patients with CAD defined as the presence of ≥1 coronary artery with ≥50% lumen stenosis by quantitative coronary angiography. Sensitivity to identify patients with CAD was greater for CTA than SPECT-MPI (0.92 versus 0.62, respectively; P<0.001), resulting in greater overall accuracy (area under the receiver operating characteristic curve, 0.91 [95% confidence interval, 0.88-0.94] versus 0.69 [0.64-0.74]; P<0.001). Results were similar in patients without previous history of CAD (area under the receiver operating characteristic curve, 0.92 [0.89-0.96] versus 0.67 [0.61-0.73]; P<0.001) and also for the secondary end points of ≥70% stenosis and multivessel disease, as well as subgroups, except for patients with a calcium score of ≥400 and those with high-risk anatomy in whom the overall accuracy was similar because CTA's superior sensitivity was offset by lower specificity in these settings. Radiation doses were 3.9 mSv for CTA and 9.8 for SPECT-MPI (P<0.001). CTA is more accurate than SPECT-MPI for the diagnosis of CAD as defined by conventional angiography and may be underused for this purpose in symptomatic patients. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00934037. © 2015 American Heart Association, Inc.

  1. Noninvasive evaluation of nicotinic acetylcholine receptor availability in mouse brain using single-photon emission computed tomography with [(123)I]5IA.

    PubMed

    Matsuura, Yuki; Ueda, Masashi; Higaki, Yusuke; Watanabe, Keiko; Habara, Shogo; Kamino, Shinichiro; Saji, Hideo; Enomoto, Shuichi

    2016-06-01

    Nicotinic acetylcholine receptors (nAChRs) are of great interest because they are implicated in higher brain functions. Nuclear medical imaging is one of the useful techniques for noninvasive evaluation of physiological and pathological function in living subjects. Recent progress in nuclear medical imaging modalities enables the clear visualization of the organs of small rodents. Thus, translational research using nuclear medical imaging in transgenic mice has become possible and helps to elucidate human disease pathology. However, imaging of α4β2 nAChRs in the mouse brain has not yet been performed. The purpose of this study was to assess the feasibility of single-photon emission computed tomography (SPECT) with 5-[(123)I]iodo-3-[2(S)-azetidinylmethoxy]pyridine ([(123)I]5IA) for evaluating α4β2 nAChR availability in the mouse brain. A 60-min dynamic SPECT imaging session of α4β2 nAChRs in the mouse brain was performed. The regional distribution of radioactivity in the SPECT images was compared to the density of α4β2 nAChRs measured in an identical mouse. Alteration of nAChR density in the brains of Tg2576 mice was also evaluated. The mouse brain was clearly visualized by [(123)I]5IA-SPECT and probe accumulation was significantly inhibited by pretreatment with (-)-nicotine. The regional distribution of radioactivity in SPECT images showed a significant positive correlation with α4β2 nAChR density measured in an identical mouse brain. Moreover, [(123)I]5IA-SPECT was able to detect the up-regulation of α4β2 nAChRs in the brains of Tg2576 transgenic mice. [(123)I]5IA-SPECT imaging would be a promising tool for evaluating α4β2 nAChR availability in the mouse brain and may be useful in translational research focused on nAChR-related diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Influence of acquisition orbit on phase analysis of gated single photon emission computed tomography myocardial perfusion imaging for assessment of left ventricular mechanical dyssynchrony.

    PubMed

    Misaka, Tomofumi; Hosono, Makoto; Kudo, Takashi; Ito, Takamichi; Syomura, Tsutomu; Uemura, Masanobu; Okajima, Kaoru

    2017-04-01

    The association between left ventricular (LV) dyssynchrony parameters, given by phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and acquisition orbits is unclear. The aim of this study was to assess the dependence of LV dyssynchrony parameters on acquisition orbits. Ninety-nine patients who underwent (201)Tl-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. Forty-four patients who underwent (99m)Tc-tetrofosmin-gated SPECT MPI were categorized into minor hypoperfusion or major hypoperfusion groups. The major hypoperfusion group with (201)Tl was divided into inferior or non-inferior wall hypoperfusion subgroups, and anteroseptal or non-anteroseptal wall hypoperfusion subgroups. Gated SPECT MPI data over a 360° acquisition orbit (360° images) and a 180° acquisition orbit (180° images) were reconstructed, and histogram bandwidth (HBW) and phase standard deviation (PSD) were compared. Between 360° and 180° images with (201)Tl, there were significant differences in HBW and PSD both globally (HBW 34.8 ± 16.6 vs. 29.1 ± 10.2; PSD 8.8 ± 4.9 vs. 7.0 ± 2.3, p < 0.05 for both) and in the inferior wall (HBW 29.5 ± 15.5 vs. 23.3 ± 9.0; PSD 7.6 ± 4.6 vs. 5.6 ± 2.4, p < 0.001 for both) in the major hypoperfusion group, and also in the inferior wall in all subgroups of the major hypoperfusion group. In contrast, no segment had any significant differences in HBW or PSD between 360° and 180° images with (99m)Tc. Differences in acquisition orbit had a significant influence on HBW and PSD with (201)Tl-gated SPECT MPI in the inferior wall in patients with major hypoperfusion myocardium.

  3. The Incremental Prognostic Value of Cardiac Computed Tomography in Comparison with Single-Photon Emission Computed Tomography in Patients with Suspected Coronary Artery Disease.

    PubMed

    Lee, Heesun; Yoon, Yeonyee E; Park, Jun-Bean; Kim, Hack-Lyoung; Park, Hyo Eun; Lee, Seung-Pyo; Kim, Hyung-Kwan; Choi, Su-Yeon; Kim, Yong-Jin; Cho, Goo-Yeong; Zo, Joo-Hee; Sohn, Dae-Won

    2016-01-01

    Coronary computed tomographic angiography (CCTA) facilitates comprehensive evaluation of coronary artery disease (CAD), including plaque characterization, and can provide additive diagnostic value to single-photon emission computed tomography (SPECT). However, data regarding the incremental prognostic value of CCTA to SPECT remain sparse. We evaluated the independent and incremental prognostic value of CCTA, as compared with clinical risk factors and SPECT. A total of 1,077 patients with suspected CAD who underwent both SPECT and cardiac CT between 2004 and 2012 were enrolled retrospectively. Presence of reversible or fixed perfusion defect (PD) and summed stress score were evaluated on SPECT. Presence, extent of coronary atherosclerosis and diameter stenosis (DS) were evaluated on CCTA. Plaque composition was categorized as non-calcified, mixed, or calcified according to the volume of calcified component (>130 Hounsfield Units). Patients were followed up for the occurrence of adverse cardiac events including cardiac death, non-fatal myocardial infarction, unstable angina, and late revascularization (>90 days after imaging studies). During follow-up (median 23 months), adverse cardiac events were observed in 71 patients (6.6%). When adjusted for clinical risk factors and SPECT findings, the presence of any coronary plaque, any plaque in ≥3 segments, coronary artery calcium score (CACS) ≥400, a plaque ≥50% DS, presence of non-calcified plaque (NCP) or mixed plaque (MP), and NCP/MP in ≥2 segments were independent predictors of adverse cardiac events; however, the presence of calcified plaque (CP) was not. Conventional CCTA findings, including CACS ≥400 and a plaque ≥50% DS, demonstrated incremental prognostic value over clinical risk factors and SPECT (χ² 54.19 to 101.03; p <0.001). Addition of NCP/MP in ≥2 segments resulted in further significantly improved prediction (χ² 101.03 to 113.29; p <0.001). Comprehensive CCTA evaluation of coronary

  4. Significance of functional hepatic resection rate calculated using 3D CT/(99m)Tc-galactosyl human serum albumin single-photon emission computed tomography fusion imaging.

    PubMed

    Tsuruga, Yosuke; Kamiyama, Toshiya; Kamachi, Hirofumi; Shimada, Shingo; Wakayama, Kenji; Orimo, Tatsuya; Kakisaka, Tatsuhiko; Yokoo, Hideki; Taketomi, Akinobu

    2016-05-07

    To evaluate the usefulness of the functional hepatic resection rate (FHRR) calculated using 3D computed tomography (CT)/(99m)Tc-galactosyl-human serum albumin (GSA) single-photon emission computed tomography (SPECT) fusion imaging for surgical decision making. We enrolled 57 patients who underwent bi- or trisectionectomy at our institution between October 2013 and March 2015. Of these, 26 patients presented with hepatocellular carcinoma, 12 with hilar cholangiocarcinoma, six with intrahepatic cholangiocarcinoma, four with liver metastasis, and nine with other diseases. All patients preoperatively underwent three-phase dynamic multidetector CT and (99m)Tc-GSA scintigraphy. We compared the parenchymal hepatic resection rate (PHRR) with the FHRR, which was defined as the resection volume counts per total liver volume counts on 3D CT/(99m)Tc-GSA SPECT fusion images. In total, 50 patients underwent bisectionectomy and seven underwent trisectionectomy. Biliary reconstruction was performed in 15 patients, including hepatopancreatoduodenectomy in two. FHRR and PHRR were 38.6 ± 19.9 and 44.5 ± 16.0, respectively; FHRR was strongly correlated with PHRR. The regression coefficient for FHRR on PHRR was 1.16 (P < 0.0001). The ratio of FHRR to PHRR for patients with preoperative therapies (transcatheter arterial chemoembolization, radiation, radiofrequency ablation, etc.), large tumors with a volume of > 1000 mL, and/or macroscopic vascular invasion was significantly smaller than that for patients without these factors (0.73 ± 0.19 vs 0.82 ± 0.18, P < 0.05). Postoperative hyperbilirubinemia was observed in six patients. Major morbidities (Clavien-Dindo grade ≥ 3) occurred in 17 patients (29.8%). There was no case of surgery-related death. Our results suggest that FHRR is an important deciding factor for major hepatectomy, because FHRR and PHRR may be discrepant owing to insufficient hepatic inflow and congestion in patients with preoperative therapies, macroscopic vascular

  5. Micro–Single-Photon Emission Computed Tomography Image Acquisition and Quantification of Sodium-Iodide Symporter–Mediated Radionuclide Accumulation in Mouse Thyroid and Salivary Glands

    PubMed Central

    Brandt, Michael P.; Kloos, Richard T.; Shen, Daniel H.; Zhang, Xiaoli; Liu, Yu-Yu

    2012-01-01

    Background Micro–single-photon emission computed tomography (SPECT) provides a noninvasive way to evaluate the effects of genetic and/or pharmacological modulation on sodium-iodide symporter (NIS)–mediated radionuclide accumulation in mouse thyroid and salivary glands. However, parameters affecting image acquisition and analysis of mouse thyroids and salivary glands have not been thoroughly investigated. In this study, we investigated the effects of region-of-interest (ROI) selection, collimation, scan time, and imaging orbit on image acquisition and quantification of thyroidal and salivary radionuclide accumulation in mice. Methods The effects of data window minima and maxima on thyroidal and salivary ROI selection using a visual boundary method were examined in SPECT images acquired from mice injected with 123I NaI. The effects of collimation, scan time, and imaging orbit on counting linearity and signal intensity were investigated using phantoms filled with various activities of 123I NaI or Tc-99m pertechnetate. Spatial resolution of target organs in whole-animal images was compared between circular orbit with parallel-hole collimation and spiral orbit with five-pinhole collimation. Lastly, the inter-experimental variability of the same mouse scanned multiple times was compared with the intra-experimental variability among different mice scanned at the same time. Results Thyroid ROI was separated from salivary glands by empirically increasing the data window maxima. Counting linearity within the range of 0.5–14.2 μCi was validated by phantom imaging using single- or multiple-pinhole collimators with circular or spiral imaging orbit. Scanning time could be shortened to 15 minutes per mouse without compromising counting linearity despite proportionally decreased signal intensity. Whole-animal imaging using a spiral orbit with five-pinhole collimators achieved a high spatial resolution and counting linearity. Finally, the extent of inter

  6. Aortic knob width reflects left ventricular diastolic function assessed by gated myocardial perfusion single photon emission computed tomography in patients with normal myocardial perfusion.

    PubMed

    Kurisu, Satoshi; Higaki, Tadanao; Sumimoto, Yoji; Ikenaga, Hiroki; Watanabe, Noriaki; Ishibashi, Ken; Dohi, Yoshihiro; Fukuda, Yukihiro; Kihara, Yasuki

    2017-04-01

    Aortic knob width on chest radiography represents the extent of aortic dialation and tortuosity of the aortic arch. We tested the hypothesis that aortic knob width reflected left ventricular (LV) diastolic function assessed by gated myocardial perfusion single photon emission computed tomography (SPECT) in patients with normal myocardial perfusion. One hundred and thirty patients with preserved LV ejection fraction and normal myocardial perfusion were enrolled in this study. Aortic knob width was measured along the horizontal line from the point of the lateral edge of the trachea to the left lateral wall of the aortic knob. The peak filling rate (PFR) and the one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters. There were 114 male and 16 female patients. Age ranged from 43 to 88 years (69.9 ± 8.9 years). Aortic knob width ranged from 24.2 to 53.4 mm (37.6 ± 5.7 mm). There was a significant correlation between age and aortic knob width (r = 0.34, p < 0.001). Aortic knob width was inversely correlated with both PFR (r = -0.53, p < 0.001) and 1/3 MFR (r = -0.42, p < 0.001). Multivariate linear regression analysis revealed that serum creatinine (β = -0.16, p = 0.045) and aortic knob width (β = -0.45, p < 0.001) were significant predictors of PFR, and that age (β = -0.20, p = 0.02) and aortic knob width (β = -0.33, p < 0.001) were significant predictors of 1/3 MFR. Our data suggested that aortic knob width on chest radiography was a simple marker of LV diastolic function in patients with normal myocardial perfusion.

  7. III-Nitride high temperature single-photon sources

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Pallab; Deshpande, Saniya; Frost, Thomas; Hazari, Arnab

    2015-03-01

    Nitride based GaN and InGaN quantum dots are excellent single-photon emitters at high temperature owing to their wide bandgap and large exciton binding energy [1-5]. In this work, two different molecular beam epitaxy (MBE) grown nanostructures have been investigated for single-photon emission: InGaN/GaN disk-in-nanowire and InGaN/GaN self-organized quantum dot. Single-photon emission under both optical and electrical excitation has been observed from a single InGaN quantum contained in a GaN nanowire p-n junction. We demonstrate electrically driven single-photon emission, with a g (2)(0) = 0.35, from a single InGaN quantum dot emitting in the green spectral range (λ=520 nm) up to 125 K. Additionally, a self-organized InGaN/GaN single quantum dot diode was grown and fabricated. Emission from a single quantum dot (λ=620 nm) shows single-photon emission with g(2)(0) = 0.29 at room temperature. On-demand single-photon emission by electrical pumping of the quantum dot at an excitation repetition rate of 200 MHz was demonstrated.

  8. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  9. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

    NASA Technical Reports Server (NTRS)

    Wagner, D. R.; Kim, H. S.; Saykally, R. J.

    2000-01-01

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  10. Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy.

    PubMed

    Wagner, D R; Kim, H S; Saykally, R J

    2000-12-20

    Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

  11. T-shaped single-photon router.

    PubMed

    Lu, Jing; Wang, Z H; Zhou, Lan

    2015-09-07

    We study the transport properties of a single photon scattered by a two-level system (TLS) in a T-shaped waveguide, which is made of two coupled-resonator waveguides (CRWs)- an infinite CRW and a semi-infinite CRW. The spontaneous emission of the TLS directs single photons from one CRW to the other. Although the transfer rate is different for the wave incident from different CRWs, due to the boundary breaking the translational symmetry, the boundary can enhance the transfer rate found in Phys. Rev. Lett. 111, 103604 (2013) and Phys. Rev. A 89, 013805 (2014), as the transfer rate could be unity for the wave incident from the semi-infinite CRW.

  12. Comparison of single-photon emission computed tomographic (SPECT) myocardial perfusion imaging with thallium-201 and technetium-99m sestamibi in dogs.

    PubMed

    Leon, A R; Eisner, R L; Martin, S E; Schmarkey, L S; Aaron, A M; Boyers, A S; Burnham, K M; Oh, D J; Patterson, R E

    1992-12-01

    The purpose of the present study was to compare single-photon emission computed tomographic (SPECT) myocardial images of technetium-99m (Tc-99m) sestamibi and thallium-201 (Tl-201) isotopes in the same dog undergoing partial coronary occlusion during pharmacologic vasodilation. To date, no controlled study has been reported comparing SPECT Tc-99m sestamibi with SPECT Tl-201 imaging during stress with anatomic and physiologic standards. Mongrel dogs were anesthetized with chloralose and instrumented to record left anterior descending coronary blood flow and aortic pressure. Partial coronary occlusion with a hydraulic cuff reduced coronary vascular conductance, which is equal to the coronary blood flow normalized to aortic pressure during peak vasodilation with intravenous adenosine. Each dog received 5 mCi of Tl-201, then 30 mCi of Tc-99m sestamibi during partial coronary occlusion at peak vasodilation. Tomographic myocardial imaging was performed in a 180 degrees anterior arc scan for 33.5 min, first with Tl-201, and later, without moving the dog, for 33.5 min with Tc-99m sestamibi. Postmortem staining defined the region underperfused because of its dependence on the artery that was partially occluded. In seven dogs with moderate reduction in coronary blood flow, coronary vascular conductance decreased with partial coronary occlusion (47 +/- 12%) during Tl-201 imaging and (47 +/- 8%, p = NS) during Tc-99m sestamibi imaging. The underperfused region was 23.9 +/- 6.4% of total left ventricular mass. Counts in the defects were 39% higher (0.86 +/- 0.08 of normal counts) for Tc-99m sestamibi than for Tl-201 (0.64 +/- 0.09 of normal counts, p < 0.001), and the defect on SPECT Tc-99m sestamibi images occupied only a fraction (0.37 +/- 0.30) of the area of the defect on the Tl-201 images of the same dog. Bull's-eye displays constructed from the pathologic slices showed that the Tl-201 defect size was closer to the underperfused region of the left ventricular mass

  13. Cardiovascular risk stratification in diabetic patients following stress single-photon emission-computed tomography myocardial perfusion imaging: the impact of achieved exercise level.

    PubMed

    Padala, Santosh K; Ghatak, Abhijit; Padala, Sandeep; Katten, Deborah M; Polk, Donna M; Heller, Gary V

    2014-12-01

    Previous studies have demonstrated that diabetic patients undergoing exercise stress single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI) have significantly lower cardiac events when compared to the diabetic patients undergoing pharmacologic stress SPECT MPI across all perfusion categories. However, there are limited data on the level of exercise achieved during exercise SPECT MPI among diabetic patients and its impact on cardiovascular outcomes. We retrospectively analyzed 14,849 consecutive patients (3,654 diabetics and 11,195 non-diabetics) undergoing exercise stress, combined exercise and pharmacologic stress, and pharmacologic stress SPECT MPI from 1996 to 2005 at a single tertiary care center. Diabetic and non-diabetic patients were categorized into 3 groups based on the metabolic equivalents (METs) achieved: ≥5 METs, <5 METs, and pharmacologic stress groups. All studies were interpreted using the 17-segment ASNC model. The presence, extent, severity of perfusion defects were calculated using the summed stress score (SSS), and patients were classified into normal (SSS < 4), mildly abnormal (SSS 4-8), and moderate-severely abnormal (SSS > 8) categories. Annualized event rates (AER) for the composite end point of non-fatal myocardial infarction and cardiac death were calculated over a mean follow-up period of 2.4 ± 1.4 years with a maximum of 6 years. In moderate-severe perfusion abnormality (SSS > 8) category, diabetic patients who were able to achieve ≥5 METs had significantly lower AER compared to diabetic patients who were unable to achieve ≥5 METs (3% vs 5.5%, P = .04), and non-diabetic patients unable to achieve ≥5 METs (3% vs 4.8%, P < .001). Diabetic patients who achieved a high workload of ≥10 METs had a very low AER of 0.9%. Diabetic patients, who attempted exercise but were unable to achieve ≥5 METs, still had significantly lower AER than diabetics undergoing pharmacologic stress MPI across all perfusion

  14. Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients

    PubMed Central

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

    2012-01-01

    This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients (16 males, 11 females) with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pallidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity (total scores of Hamilton Depression Rating Scale) was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients. PMID:25558229

  15. Single-photon decision maker

    PubMed Central

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

    2015-01-01

    Decision making is critical in our daily lives and for society in general and is finding evermore practical applications in information and communication technologies. Herein, we demonstrate experimentally that single photons can be used to make decisions in uncertain, dynamically changing environments. Using a nitrogen-vacancy in a nanodiamond as a single-photon source, we demonstrate the decision-making capability by solving the multi-armed bandit problem. This capability is directly and immediately associated with single-photon detection in the proposed architecture, leading to adequate and adaptive autonomous decision making. This study makes it possible to create systems that benefit from the quantum nature of light to perform practical and vital intelligent functions. PMID:26278007

  16. Single-photon decision maker

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  17. Single-photon decision maker.

    PubMed

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

    2015-08-17

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

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

    PubMed

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

    2015-01-01

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

  19. Highly Directional Room-Temperature Single Photon Device.

    PubMed

    Livneh, Nitzan; Harats, Moshe G; Istrati, Daniel; Eisenberg, Hagai S; Rapaport, Ronen

    2016-04-13

    One of the most important challenges in modern quantum optical applications is the demonstration of efficient, scalable, on-chip single photon sources, which can operate at room temperature. In this paper we demonstrate a room-temperature single photon source based on a single colloidal nanocrystal quantum dot positioned inside a circular bulls-eye shaped hybrid metal-dielectric nanoantenna. Experimental results show that 20% of the photons are emitted into a very low numerical aperture (NA < 0.25), a 20-fold improvement over a free-standing quantum dot, and with a probability of more than 70% for a single photon emission. With an NA = 0.65 more than 35% of the single photon emission is collected. The single photon purity is limited only by emission from the metal, an obstacle that can be bypassed with careful design and fabrication. The concept presented here can be extended to many other types of quantum emitters. Such a device paves a promising route for a high purity, high efficiency, on-chip single photon source operating at room temperature.

  20. Single photon searches at PEP

    SciTech Connect

    Hollebeek, R.

    1985-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Breddermann, D.; Heinze, D.; Binder, R.; Zrenner, A.; Schumacher, S.

    2016-10-01

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

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

    SciTech Connect

    Paul, Matthias Kettler, Jan; Zeuner, Katharina; Clausen, Caterina; Jetter, Michael; Michler, Peter

    2015-03-23

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

  3. Whole-body imaging of adoptively transferred T cells using magnetic resonance imaging, single photon emission computed tomography and positron emission tomography techniques, with a focus on regulatory T cells

    PubMed Central

    Leech, J M; Sharif-Paghaleh, E; Maher, J; Livieratos, L; Lechler, R I; Mullen, G E; Lombardi, G; Smyth, L A

    2013-01-01

    Cell-based therapies using natural or genetically modified regulatory T cells (Tregs) have shown significant promise as immune-based therapies. One of the main difficulties facing the further advancement of these therapies is that the fate and localization of adoptively transferred Tregs is largely unknown. The ability to dissect the migratory pathway of these cells in a non-invasive manner is of vital importance for the further development of in-vivo cell-based immunotherapies, as this technology allows the fate of the therapeutically administered cell to be imaged in real time. In this review we will provide an overview of the current clinical imaging techniques used to track T cells and Tregs in vivo, including magnetic resonance imaging (MRI) and positron emission tomography (PET)/single photon emission computed tomography (SPECT). In addition, we will discuss how the finding of these studies can be used, in the context of transplantation, to define the most appropriate Treg subset required for cellular therapy. PMID:23574314

  4. Effects of myocardial perfusion abnormalities on the accuracy of left ventricular volume and ejection fraction measured by thallium-201 gated single-photon emission tomography: comparison with echocardiography as the reference standard.

    PubMed

    Kurisu, Satoshi; Iwasaki, Toshitaka; Abe, Nobukazu; Tamura, Megumi; Ikenaga, Hiroki; Watanabe, Noriaki; Higaki, Tadanao; Shimonaga, Takashi; Ishibashi, Ken; Dohi, Yoshihiro; Fukuda, Yukihiro; Kihara, Yasuki

    2015-11-01

    We assessed the accuracy of left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) using quantitative gated single-photon emission computed tomography (QGS) in comparison with echocardiography as the reference standard. We also assessed the effects of total perfusion deficit (TPD) on the accuracy of QGS measurements. A total of 258 patients underwent single-photon emission computed tomography and transthoracic echocardiography within 4 weeks of each investigation for evaluating coronary artery disease. Patients were divided into four groups according to TPD scores. There were 138 patients with no/minimal TPD, 64 patients with small TPD, 35 patients with middle TPD, and 21 patients with large TPD. There were good correlations and agreements in EDV (r=0.87, 0.90, 0.71, and 0.94, respectively), ESV (r=0.92, 0.94, 0.79, and 0.94, respectively), and EF (r=0.61, 0.79, 0.61, and 0.83, respectively) between QGS and echocardiography in patients with any TPD. QGS significantly underestimated EDV and ESV in patients with no/minimal or small TPD, and significantly overestimated ESV in patients with large TPD. QGS significantly underestimated EF in patients with middle or large TPD. Our results suggest that QGS is a useful tool for assessing the left ventricular volume and function in patients with any TPD, but myocardial perfusion abnormalities should be taken into consideration when interpreting QRS measurements.

  5. Ramsey Interference with Single Photons

    NASA Astrophysics Data System (ADS)

    Clemmen, Stéphane; Farsi, Alessandro; Ramelow, Sven; Gaeta, Alexander L.

    2016-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  7. Correlation of Technetium-99m Macroaggregated Albumin and Yttrium-90 Glass Microsphere Biodistribution in Hepatocellular Carcinoma: A Retrospective Review of Pretreatment Single Photon Emission CT and Posttreatment Positron Emission Tomography/CT.

    PubMed

    Haste, Paul; Tann, Mark; Persohn, Scott; LaRoche, Thomas; Aaron, Vasantha; Mauxion, Thibault; Chauhan, Nikhil; Dreher, Matthew R; Johnson, Matthew S

    2017-05-01

    To evaluate whether technetium-99 ((99m)Tc)-labeled macroaggregated albumin (MAA) can predict subsequent yttrium-90 ((90)Y) distribution and imaging response in patients with hepatocellular carcinoma (HCC). Retrospective review was performed of records of 83 patients with HCC who underwent (90)Y glass microsphere radioembolization with (99m)Tc-MAA single photon emission computed tomography (SPECT) and (90)Y positron emission tomography (PET)/CT between January 2013 and December 2014. Images were fused to segment the whole liver normal tissue (WLNT) and the largest tumors. Fused images were reviewed and analyzed for comparison of absorbed dose (AD) to tumors and WLNT as calculated from (99m)Tc-MAA SPECT and from (90)Y PET/CT, subjective imaging comparison of (99m)Tc-MAA SPECT and (90)Y PET for tumors and WLNT, and correlation of tumoral AD with response on follow-up CT. Final analysis included 73 and 63 patients for WLNT and tumor (99m)Tc-MAA/(90)Y correlation, respectively, and 62 patients for AD vs response. (99m)Tc-MAA/(90)Y limit of agreement for each reviewer was viewed as clinically acceptable only for WLNT (-15 to 15 Gy). AD interreviewer variability was clinically acceptable for WLNT but was too broad for tumor. Mean tumor AD for objective response (78%) was 313 Gy vs 234 Gy for nonresponders. No threshold was found between tumor AD and response (P > .1). Catheter mismatch between (99m)Tc-MAA and (90)Y had a direct impact on AD mismatch between the 2 image sets. (99m)Tc-MAA was found to be a poor surrogate to quantitatively predict subsequent (90)Y AD to hepatocellular tumors. (99m)Tc-MAA distribution correlated with (90)Y distribution in the normal hepatic parenchyma. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

  8. Enhancement of Single-Photon Sources with Metamaterials

    NASA Astrophysics Data System (ADS)

    Shalaginov, M. Y.; Bogdanov, S.; Vorobyov, V. V.; Lagutchev, A. S.; Kildishev, A. V.; Akimov, A. V.; Boltasseva, A.; Shalaev, V. M.

    2015-06-01

    Scientists are looking for new, breakthrough solutions that can greatly advance computing and networking systems. These solutions will involve quantum properties of matter and light as promised by the ongoing experimental and theoretical work in the areas of quantum computation and communication. Quantum photonics is destined to play a central role in the development of such technologies due to the high transmission capacity and outstanding low-noise properties of photonic information channels. Among the vital problems to be solved in this direction, are efficient generation and collection of single photons. One approach to tackle these problems is based on engineering emission properties of available single-photon sources using metamaterials. Metamaterials are artificially engineered structures with sub-wavelength features whose optical properties go beyond the limitations of conventional materials. As promising single-photon sources, we have chosen nitrogen-vacancy (NV) color centers in diamond, which are capable to operate stably in a single-photon regime at room temperature in a solid state environment. In this chapter, we report both theoretical and experimental studies of the radiation from a nanodiamond single NV center placed near a hyperbolic metamaterial (HMM). In particular, we derive the reduction of excited-state lifetime and the enhancement of collected single-photon emission rate and compare them with the experimental observations. These results could be of great impact for future integrated quantum sources, especially owing to a CMOS-compatible approach to HMM synthesis.

  9. MR-IMPACT II: Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary artery disease Trial: perfusion-cardiac magnetic resonance vs. single-photon emission computed tomography for the detection of coronary artery disease: a comparative multicentre, multivendor trial.

    PubMed

    Schwitter, Juerg; Wacker, Christian M; Wilke, Norbert; Al-Saadi, Nidal; Sauer, Ekkehart; Huettle, Kalman; Schönberg, Stefan O; Luchner, Andreas; Strohm, Oliver; Ahlstrom, Hakan; Dill, Thorsten; Hoebel, Nadja; Simor, Tamas

    2013-03-01

    Perfusion-cardiac magnetic resonance (CMR) has emerged as a potential alternative to single-photon emission computed tomography (SPECT) to assess myocardial ischaemia non-invasively. The goal was to compare the diagnostic performance of perfusion-CMR and SPECT for the detection of coronary artery disease (CAD) using conventional X-ray coronary angiography (CXA) as the reference standard. In this multivendor trial, 533 patients, eligible for CXA or SPECT, were enrolled in 33 centres (USA and Europe) with 515 patients receiving MR contrast medium. Single-photon emission computed tomography and CXA were performed within 4 weeks before or after C