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Sample records for detection emission tomography

  1. [TUBERCULOUS CONSTRICTIVE PERICARDITIS DETECTED ON POSITRON EMISSION TOMOGRAPHY].

    PubMed

    Takakura, Hiroki; Sunada, Kouichi; Shimizu, Kunihiko

    2016-02-01

    A 72-year-old man presented with fever, dyspnea, and weight loss. He was referred to our hospital for further examination of the cause of the pleural effusions. Chest computed tomography showed pleural effusions, a pericardial effusion, and enlarged lymph nodes in the carina tracheae. We administered treatment for heart failure and conducted analyses for a malignant tumor. The pericardial effusion improved, but the pericardium was thickened. Positron emission tomography-computed tomography (PET-CT) showed fluorine-18 deoxyglucose accumulation at the superior fovea of the right clavicle, carina tracheae, superior mediastinum lymph nodes, and a thickened pericardium. Because these findings did not suggest malignancy, we assumed this was a tuberculous lesion. Echocardiography confirmed this finding as constrictive pericarditis; therefore, pericardiolysis was performed. Pathological examination showed features of caseous necrosis and granulomatous changes. Hence, the patient was diagnosed with tuberculous constrictive pericarditis. PET-CT serves as a useful tool for the diagnosis of tuberculous pericarditis. PMID:27263228

  2. Detection of lung cancer in patients with pneumoconiosis by fluorodeoxyglucose-positron emission tomography/computed tomography: four cases.

    PubMed

    Yu, Hua; Zhang, Hua; Wang, Yanli; Cui, Xinjian; Han, Jiankui

    2013-01-01

    We report 4 cases of lung cancer in patients with pneumoconiosis detected by F18-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), which could differentiate lung cancer and pneumoconiosis. FDG-PET/CT may be useful in cancer screening for patients with pneumoconiosis.

  3. Extramedullary Plasmacytoma of the Gallbladder Detected on Fluorine 18-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Fakhri, Asif Ali; Rodrigue, Paul David; Fakhri, Amena Fatima

    2016-01-01

    Extramedullary plasmacytoma is rare in patients with diagnosed multiple myeloma. Soft tissue plasmacytoma of the gallbladder is particularly uncommon and has been described in only a handful of cases. Diagnosis of gallbladder plasmacytoma with fluorine 18-fluorodeoxyglucose (F18-FDG) positron emission tomography/computed tomography (PET/CT) has not previously been reported. We present a 65-year-old female with a history of multiple myeloma who underwent a restaging F18-FDG-PET/CT which showed a focal area of hypermetabolic activity, corresponding to a nodular lesion within the posterior gallbladder wall. The patient underwent successful cholecystectomy, with surgical pathology revealing gallbladder plasmacytoma. A follow-up scan was negative for active malignancy. This is a novel case of gallbladder plasmacytoma diagnosed on whole-body F18-FDG PET/CT – thus demonstrating the clinical value of this imaging modality in staging, restaging, and surveillance for patients with multiple myeloma. PMID:27761300

  4. Detection of scalene lymph node metastases from lung cancer. Positron emission tomography.

    PubMed

    Scott, W J; Gobar, L S; Hauser, L G; Sunderland, J J; Dewan, N A; Sugimoto, J T

    1995-04-01

    Preliminary data indicate that positron emission tomography (PET) following injection of fluorodeoxyglucose F18 (FDG) is sensitive and specific for detecting malignant cells in chest tumors and mediastinal lymph nodes. We report a case of non-small cell lung cancer metastatic to clinically normal scalene lymph nodes that was correctly staged by FDG-PET. PMID:7705136

  5. Cerebrospinal fluid analysis detects cerebral amyloid-β accumulation earlier than positron emission tomography

    PubMed Central

    Mattsson, Niklas

    2016-01-01

    See Rabinovici (doi:10.1093/brain/aww025) for a scientific commentary on this article. Cerebral accumulation of amyloid-β is thought to be the starting mechanism in Alzheimer’s disease. Amyloid-β can be detected by analysis of cerebrospinal fluid amyloid-β42 or amyloid positron emission tomography, but it is unknown if any of the methods can identify an abnormal amyloid accumulation prior to the other. Our aim was to determine whether cerebrospinal fluid amyloid-β42 change before amyloid PET during preclinical stages of Alzheimer’s disease. We included 437 non-demented subjects from the prospective, longitudinal Alzheimer’s Disease Neuroimaging Initiative (ADNI) study. All underwent 18F-florbetapir positron emission tomography and cerebrospinal fluid amyloid-β42 analysis at baseline and at least one additional positron emission tomography after a mean follow-up of 2.1 years (range 1.1–4.4 years). Group classifications were based on normal and abnormal cerebrospinal fluid and positron emission tomography results at baseline. We found that cases with isolated abnormal cerebrospinal fluid amyloid-β and normal positron emission tomography at baseline accumulated amyloid with a mean rate of 1.2%/year, which was similar to the rate in cases with both abnormal cerebrospinal fluid and positron emission tomography (1.2%/year, P = 0.86). The mean accumulation rate of those with isolated abnormal cerebrospinal fluid was more than three times that of those with both normal cerebrospinal fluid and positron emission tomography (0.35%/year, P = 0.018). The group differences were similar when analysing yearly change in standardized uptake value ratio of florbetapir instead of percentage change. Those with both abnormal cerebrospinal fluid and positron emission tomography deteriorated more in memory and hippocampal volume compared with the other groups (P < 0.001), indicating that they were closer to Alzheimer’s disease dementia. The results were replicated after

  6. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-01-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of “sclerosing pneumocytoma,” is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up. PMID:25210285

  7. Multiple pulmonary sclerosing hemangiomas (pneumocytoma) mimicking lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Rajan, Firoz; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-07-01

    Pulmonary sclerosing hemangioma (PSH), or the alternative name of "sclerosing pneumocytoma," is a rare benign neoplasm. PSH is often asymptomatic and presents as a solitary or multiple pulmonary nodules on radiologic imaging studies. Few articles have been reported to describe the fluorodeoxyglucose positron emission tomography (FDG PET) findings about PSH. The authors describe an interesting but uncommonly encountered cause of false positive FDG PET scan in the thorax in a 25-year-old woman, a known case of arteriovenous malformation of oral cavity who underwent embolization and presented with incidental detection of bilateral lung nodules. She is asymptomatic and is on follow-up.

  8. [Inflammatory activity in Takayasu arteritis. Detection through positron emission tomography (PET)].

    PubMed

    Alexánderson, Erick; Soto, María Elena; Ricalde, Alejandro; Meave, Aloha; Reyes, Pedro

    2005-01-01

    Takayasu arteritis (TA) is a chronic disease that affects mainly the aorta. Its etiology is still unknown, nevertheless it predominates in women and initiates primarily in the youth. This disease seems to have two different stages, an early stage that is characterized by an inflammatory process and a later stage characterized by vascular occlusion. Unitl now, diagnosis and classification of TA are made clinically, based on ACR; criteria and imaging studies as computed tomography and aorta angiographies. Currently, new imaging, non invasive studies, such as magnetic resonance (MRI) and positron emission tomography (PET) are being used. PET technique could be helpful in the diagnosis and detection of inflammatory activity in patients with TA because of its capacity to detect increased metabolism. We present the case of a female patient with TA diagnosis, which demonstrated clinical inflammatory activity that was corroborated by laboratory studies, MRI and PET. PMID:15909745

  9. Rare case of isolated splenic metastases from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Sivanesan, Balasubramanian; Shibu, Deepu; Shinto, Ajit Sugunan

    2013-04-01

    We report a rare case of isolated splenic metastasis from gastric cancer detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT). A 55-year-old man with gastric cancer 1 year post surgery, evaluated with PET/CT showed focal, intense uptake in the spleen, with no other abnormal findings. On splenectomy, the lesion was confirmed as metastasis from gastric cancer pathologically.

  10. Low background high efficiency radiocesium detection system based on positron emission tomography technology

    SciTech Connect

    Yamamoto, Seiichi; Ogata, Yoshimune

    2013-09-15

    After the 2011 nuclear power plant accident at Fukushima, radiocesium contamination in food became a serious concern in Japan. However, low background and high efficiency radiocesium detectors are expensive and huge, including semiconductor germanium detectors. To solve this problem, we developed a radiocesium detector by employing positron emission tomography (PET) technology. Because {sup 134}Cs emits two gamma photons (795 and 605 keV) within 5 ps, they can selectively be measured with coincidence. Such major environmental gamma photons as {sup 40}K (1.46 MeV) are single photon emitters and a coincidence measurement reduces the detection limit of radiocesium detectors. We arranged eight sets of Bi{sub 4}Ge{sub 3}O{sub 12} (BGO) scintillation detectors in double rings (four for each ring) and measured the coincidence between these detectors using PET data acquisition system. A 50 × 50 × 30 mm BGO was optically coupled to a 2 in. square photomultiplier tube (PMT). By measuring the coincidence, we eliminated most single gamma photons from the energy distribution and only detected those from {sup 134}Cs at an average efficiency of 12%. The minimum detectable concentration of the system for the 100 s acquisition time is less than half of the food monitor requirements in Japan (25 Bq/kg). These results show that the developed radiocesium detector based on PET technology is promising to detect low level radiocesium.

  11. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    NASA Astrophysics Data System (ADS)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  12. Importance of Defect Detectability in Positron Emission Tomography Imaging of Abdominal Lesions

    PubMed Central

    Yamashita, Shozo; Yokoyama, Kunihiko; Onoguchi, Masahisa; Yamamoto, Haruki; Nakaichi, Tetsu; Tsuji, Shiro; Nakajima, Kenichi

    2015-01-01

    Objective(s): This study was designed to assess defect detectability in positron emission tomography (PET) imaging of abdominal lesions. Methods: A National Electrical Manufactures Association International Electrotechnical Commission phantom was used. The simulated abdominal lesion was scanned for 10 min using dynamic list-mode acquisition method. Images, acquired with scan duration of 1-10 min, were reconstructed using VUE point HD and a 4.7 mm full-width at half-maximum (FWHM) Gaussian filter. Iteration-subset combinations of 2-16 and 2-32 were used. Visual and physical analyses were performed using the acquired images. To sequentially evaluate defect detectability in clinical settings, we examined two middle-aged male subjects. One had a liver cyst (approximately 10 mm in diameter) and the other suffered from pancreatic cancer with an inner defect region (approximately 9 mm in diameter). Results: In the phantom study, at least 6 and 3 min acquisition durations were required to visualize 10 and 13 mm defect spheres, respectively. On the other hand, spheres with diameters ≥17 mm could be detected even if the acquisition duration was only 1 min. The visual scores were significantly correlated with background (BG) variability. In clinical settings, the liver cyst could be slightly visualized with an acquisition duration of 6 min, although image quality was suboptimal. For pancreatic cancer, the acquisition duration of 3 min was insufficient to clearly describe the defect region. Conclusion: The improvement of BG variability is the most important factor for enhancing lesion detection. Our clinical scan duration (3 min/bed) may not be suitable for the detection of small lesions or accurate tumor delineation since an acquisition duration of at least 6 min is required to visualize 10 mm lesions, regardless of reconstruction parameters. Improvements in defect detectability are important for radiation treatment planning and accurate PET-based diagnosis. PMID:27408887

  13. Detection of neuronal damage in degenerative brain disease with cobalt-55 and positron emission tomography

    SciTech Connect

    Jansen, H.M.L.; Pruim, J.; Paans, A.M.J.

    1994-05-01

    We suggest Cobalt-55 (Co) as a Calcium (Ca)-marker to visualize Ca transport across the neuronal membrane. Elevation of intracellular Ca is closely linked with the process of neuronal cell-decay. Co-uptake is correlated with Ca-accumulation through divalent cation-permeable kainate (KA)-activated receptor-operated channels in the neuronal membrane. This hypothesis was studied with position emission tomography (PET) both in patients with a ischemic cerebro-vascular accident (CVA) and in patients with relapsing progressive multiple sclerosis (MS). Co-PET studies were performed in a dynamic mode (6 frames of 10 minutes) 20-25 hours after iv.-administration of 1-2 mCi Co. Regional specific accumulation irrespective of blood brain barrier (BBB) integrity in the (clinically appropriate) affected cerebral region could be demonstrated in CVA-patients, thus suggesting neuronal decay in (the early phase of) infarction. In MS, inhomogeneous cerebral distribution of Co was detected, in contrast to healthy volunteers. This suggests focal accumulation of Co in multiple spots of neuronal decay, possibly related to MS-lesions on MRI. In conclusion, Co-PET may prove to be a valuable tool for the early detection of neuronal decay not only in CVA and MS, but in other brain-pathology as well. The usefulness of Co-PET in imaging brain-tumors and myocardial ischemia has already been established.

  14. Positron emission tomography detects tissue metabolic activity in myocardial segments with persistent thallium perfusion defects

    SciTech Connect

    Brunken, R.; Schwaiger, M.; Grover-McKay, M.; Phelps, M.E.; Tillisch, J.; Schelbert, H.R.

    1987-09-01

    Positron emission tomography with /sup 13/N-ammonia and /sup 18/F-2-deoxyglucose was used to assess myocardial perfusion and glucose utilization in 51 myocardial segments with a stress thallium defect in 12 patients. Myocardial infarction was defined by a concordant reduction in segmental perfusion and glucose utilization, and myocardial ischemia was identified by preservation of glucose utilization in segments with rest hypoperfusion. Of the 51 segments studied, 36 had a fixed thallium defect, 11 had a partially reversible defect and 4 had a completely reversible defect. Only 15 (42%) of the 36 segments with a fixed defect and 4 (36%) of the 11 segments with a partially reversible defect exhibited myocardial infarction on study with positron tomography. In contrast, residual myocardial glucose utilization was identified in the majority of segments with a fixed (58%) or a partially reversible (64%) thallium defect. All of the segments with a completely reversible defect appeared normal on positron tomography. Apparent improvement in the thallium defect on delayed images did not distinguish segments with ischemia from infarction. Thus, positron emission tomography reveals evidence of persistent tissue metabolism in the majority of segments with a fixed or partially resolving stress thallium defect, implying that markers of perfusion alone may underestimate the extent of viable tissue in hypoperfused myocardial segments.

  15. Cardiac Positron Emission Tomography

    PubMed Central

    Geltman, Edward M.

    1985-01-01

    Positron emission tomography (PET) is a new technique for noninvasively assessing myocardial metabolism and perfusion. It has provided new insight into the dynamics of myocardial fatty acid and glucose metabolism in normal subjects, patients with ischemic heart disease and those with cardiomyopathies, documenting regionally depressed fatty acid metabolism during myocardial ischemia and infarction and spatial heterogeneity of fatty acid metabolism in patients with cardiomyopathy. Regional myocardial perfusion has been studied with PET using water, ammonia and rubidium labeled with positron emitters, permitting the noninvasive detection of hypoperfused zones at rest and during vasodilator stress. With these techniques the relationship between perfusion and the metabolism of a variety of substrates has been studied. The great strides that have been made in developing faster high-resolution instruments and producing new labeled intermediates indicate the promise of this technique for facilitating an increase in the understanding of regional metabolism and blood flow under normal and pathophysiologic conditions. ImagesFigure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:3879048

  16. Positron Emission Tomography (PET)

    SciTech Connect

    Welch, M.J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.

  17. Positron Emission Tomography (PET)

    DOE R&D Accomplishments Database

    Welch, M. J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

  18. Generalized local emission tomography

    DOEpatents

    Katsevich, Alexander J.

    1998-01-01

    Emission tomography enables locations and values of internal isotope density distributions to be determined from radiation emitted from the whole object. In the method for locating the values of discontinuities, the intensities of radiation emitted from either the whole object or a region of the object containing the discontinuities are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the isotope density discontinuity. The asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) is determined in a neighborhood of S, and the value for the discontinuity is estimated from the asymptotic behavior of .function..sub..LAMBDA..sup.(.PHI.) knowing pointwise values of the attenuation coefficient within the object. In the method for determining the location of the discontinuity, the intensities of radiation emitted from an object are inputted to a local tomography function .function..sub..LAMBDA..sup.(.PHI.) to define the location S of the density discontinuity and the location .GAMMA. of the attenuation coefficient discontinuity. Pointwise values of the attenuation coefficient within the object need not be known in this case.

  19. Applications of Beta Particle Detection for Synthesis and Usage of Radiotracers Developed for Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Dooraghi, Alex Abreu

    Positron Emission Tomography (PET) is a noninvasive molecular imaging tool that requires the use of a radioactive compound or radiotracer which targets a molecular pathway of interest. We have developed and employed three beta particle radiation detection systems to advance PET. Specifically, the goals of these systems are to: 1. Automate dispensing of solutions containing a positron emitting isotope. 2. Monitor radioactivity on-chip during synthesis of a positron emitting radiotracer. 3. Assay cellular uptake on-chip of a positron emitting radiotracer. Automated protocols for measuring and dispensing solutions containing radioisotopes are essential not only for providing an optimum environment for radiation workers, but also to ensure a quantitatively accurate workflow. For the first project, we describe the development and performance of a system for automated radioactivity distribution of beta particle emitting radioisotopes such as fluorine-18 (F-18). Key to the system is a radiation detector in-line with a peristaltic pump. The system demonstrates volume accuracy within 5 % for volumes of 20 muL or greater. When considering volumes of 20 muL or greater, delivered radioactivity is in agreement with the requested radioactivity as measured with the dose calibrator. The integration of the detector and pump leads to a flexible system that can accurately dispense solutions containing F-18 in radioactivity concentrations directly produced from a cyclotron (~ 0.1-1 mCi/muL), to low activity concentrations intended for preclinical mouse scans (~ 1-10 muCi/muL), and anywhere in between. Electrowetting on dielectric (EWOD) is an attractive microfluidic platform for batch synthesis of PET radiotracers. Visualization of radioisotopes on-chip is critical for synthesis optimization and technological development. For the second project, we describe the development and performance of a Cerenkov/real-time imaging system for PET radiotracer synthesis on EWOD. We also investigate

  20. The role of positron emission tomography in the detection of pancreatic disease

    SciTech Connect

    Syrota, A.; Duquesnoy, N.; Paraf, A.; Kellershohn, C.

    1982-04-01

    Positron emission tomography (PET) was used to assess possible pancreatic disease in 100 patients. Following injection of 10-15 mCi (370-740 MBq) of 11C-L-methionine, 4-12 transverse sections 2 cm thick were obtained. In 85 patients with a definite diagnosis (45 normal, 9 acute pancreatitis, 18 chronic pancreatitis, and 13 cancer), PET showed a sensitivity of 85.0%, a specificity of 97.8%, and an accuracy of 91.8%, higher than with transmission computed tomography (CT) or ultrasonography, despite relatively low spatial resolution; this can be explained by the fact that exocrine pancreatic function was altered prior to morphological change. In 22 normal subjects, 0.011 +/- 0.003% (mean +/- S.D). of injected 11C was found in 1 ml of liver tissue and 0.015 +/- 0.005% in 1 ml of pancreatic tissue; the pancreas-to-liver concentration ratio was 1.3 +/- 0.4. Hepatic 11C concentration was identical in the four groups of patients. Pancreatic uptake of 11C-L-methionine was significantly lower in patients with chronic pancreatitis (n . 13) and pancreatic carcinoma (n . 10) (p less than 0.001); however, it was not possible to distinguish cancer from chronic pancreatitis because the same functional alteration occurred in both.

  1. The role of positron emission tomography in the detection of pancreatic disease

    SciTech Connect

    Syrota, A.; Duquesnoy, N.; Paraf, A.; Kellershohn, C.

    1982-04-01

    Positron emission tomography (PET) was used to assess possible pancreatic disease in 100 patients. Following injection of 10-15 mCi (370-740 MBq) of /sup 11/C-L-methionine, 4-12 transverse sections 2 cm thick were obtained. In 85 patients with a definite diagnosis (45 normal, 9 acute pancreatitis, 18 chronic pancreatitis, and 13 cancer), PET showed a sensitivity of 85.0%, a specificity of 97.8%, and an accuracy of 91.8%, higher than with transmission computed tomography (CT) or ultrasonography, despite relatively low spatial resolution; this can be explained by the fact that exocrine pancreatic function was altered prior to morphological change. In 22 normal subjects, 0.011 +/- 0.003% (mean +/- S.D.) of injected /sup 11/C was found in 1 ml of liver tissue and 0.015 +/- 0.005% in 1 ml of pancreatic tissue; the pancreas-to-liver concentration ratio was 1.3 +/- 0.4. Hepatic /sup 11/C concentration was identical in the four groups of patients. Pancreatic uptake of /sup 11/C-L-methionine was significantly lower in patients with chronic pancreatitis (n = 13) and pancreatic carcinoma (n = 10) (p <0.001); however, it was not possible to distinguish cancer from chronic pancreatitis because the same functional alteration occurred in both.

  2. Positron Emission Tomography.

    PubMed

    Lameka, Katherine; Farwell, Michael D; Ichise, Masanori

    2016-01-01

    Positron emission tomography (PET) is a minimally invasive imaging procedure with a wide range of clinical and research applications. PET allows for the three-dimensional mapping of administered positron-emitting radiopharmaceuticals such as (18)F-fluorodeoxyglucose (for imaging glucose metabolism). PET enables the study of biologic function in both health and disease, in contrast to magnetic resonance imaging (MRI) and computed tomography (CT), that are more suited to study a body's morphologic changes, although functional MRI can also be used to study certain brain functions by measuring blood flow changes during task performance. This chapter first provides an overview of the basic physics principles and instrumentation behind PET methodology, with an introduction to the merits of merging functional PET imaging with anatomic CT or MRI imaging. We then focus on clinical neurologic disorders, and reference research on relevant PET radiopharmaceuticals when applicable. We then provide an overview of PET scan interpretation and findings in several specific neurologic disorders such as dementias, epilepsy, movement disorders, infection, cerebrovascular disorders, and brain tumors. PMID:27432667

  3. A follow-up analysis of positron emission tomography/computed tomography in detecting hidden malignancies at the time of diagnosis of membranous nephropathy

    PubMed Central

    Feng, Zhonglin; Wang, Shuxia; Huang, Yanlin; Liang, Xinling; Shi, Wei; Zhang, Bin

    2016-01-01

    Membranous nephropathy (MN) is the most common kidney disease reported in a variety of malignant diseases. Search for an occult malignancy in MN has presented special challenges. 124 MN patients with a physical examination not suspicious for cancer underwent screening for an occult malignancy with either 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scanning (n = 49) or conventional screening (n = 75) at the time of diagnosis of MN, and were followed up (median,28 months). 154 patients who refused to undergo any screening were followed up (median, 30 months). In FDG-PET/CT cohort, 5 (10.20%) patients were screened and confirmed as malignancy, in contrast, 1 (1.33%) patient in conventional screening cohort. During follow-up, none of malignancy was detected in FDG-PET/CT cohort, 3(4.05%) patients in conventional screening cohort, and 8(5.19%) patients in no-screening cohort. All 6 cases of cancer were detected at early stages and underwent curative resection, and after the resection, proteinuria decreased. In contrast, 11 cases of cancer detected during follow-up died without any remission of proteinuria. These preliminary data provide the first evidence for a potential cancer surveillance that the malignancy screening either through conventional or by PET-CT at the diagnosis of MN led to an early diagnosis and curative treatment. PMID:27009881

  4. Detection of bone marrow involvement in newly diagnosed post-transplant lymphoproliferative disorder: (18)F-fluorodeoxyglucose positron emission tomography/computed tomography versus bone marrow biopsy.

    PubMed

    Gheysens, Olivier; Thielemans, Sanne; Morscio, Julie; Boeckx, Nancy; Goffin, Karolien E; Deroose, Christophe M; Sagaert, Xavier; Wlodarska, Iwona; Verhoef, Gregor; Dierickx, Daan; Tousseyn, Thomas

    2016-10-01

    Detecting bone marrow involvement (BMI) in lymphoma is important as it adversely affects stage. Bone marrow biopsy (BMB) remains the standard to detect BMI but is prone to sampling error. We retrospectively investigated whether (18)F-fluorodeoxyglucose positron emission tomography with computed tomography ((18)F-FDG-PET/CT) could identify BMI in patients with post-transplant lymphoproliferative disorder (PTLD) with sufficient accuracy in comparison with staging BMB. Twenty-five patients diagnosed with PTLD who underwent (18)F-FDG-PET/CT and BMB within one month were evaluated. Based on our criteria, six patients (24%) were considered positive for BMI on (18)F-FDG-PET/CT compared to one by BMB. Although we cannot completely exclude false positive results on (18)F-FDG-PET/CT, our data indicate a significantly higher sensitivity of (18)F-FDG-PET/CT compared to BMB (100% vs 17%) but similar specificity. These data confirm the high diagnostic performance of (18)F-FDG-PET/CT for detecting BMI, but prospective studies are needed to determine whether (18)F-FDG-PET/CT could indeed replace staging BMB in PTLD.

  5. Positron emission tomography wrist detector

    DOEpatents

    Schlyer, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois

    2006-08-15

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal representing a time-of-occurrence of an annihilation event, generating an address signal representing a channel detecting the annihilation event, and generating a channel signal including the time and address signals. The method also includes generating a composite signal including the channel signal and another similarly generated channel signal concerning another annihilation event. An apparatus that serially transfers annihilation information includes a time signal generator, address signal generator, channel signal generator, and composite signal generator. The time signal is asynchronous and the address signal is synchronous to a clock signal. A PET scanner includes a scintillation array, detection array, front-end array, and a serial encoder. The serial encoders include the time signal generator, address signal generator, channel signal generator, and composite signal generator.

  6. Comparison of rubidium-82 positron emission tomography and thallium-201 SPECT imaging for detection of coronary artery disease

    SciTech Connect

    Stewart, R.E.; Schwaiger, M.; Molina, E.; Popma, J.; Gacioch, G.M.; Kalus, M.; Squicciarini, S.; al-Aouar, Z.R.; Schork, A.; Kuhl, D.E. )

    1991-06-15

    The diagnostic performance of rubidium-82 (Rb-82) positron emission tomography (PET) and thallium-201 (Tl-201) single-photon emission-computed tomography (SPECT) for detecting coronary artery disease was investigated in 81 patients (52 men, 29 women). PET studies using 60 mCi of Rb-82 were performed at baseline and after intravenous infusion of 0.56 mg/kg dipyridamole in conjunction with handgrip stress. Tl-201 SPECT was performed after dipyridamole-handgrip stress and, in a subset of patients, after treadmill exercise. Sensitivity, specificity and overall diagnostic accuracy were assessed using both visually and quantitatively interpreted coronary angiograms. The overall sensitivity, specificity and accuracy of PET for detection of coronary artery disease (greater than 50% diameter stenosis) were 84, 88 and 85%, respectively. In comparison, the performance of SPECT revealed a sensitivity of 84%, specificity of 53% (p less than 0.05 vs PET) and accuracy of 79%. Similar results were obtained using either visual or quantitative angiographic criteria for severity of coronary artery disease. In 43 patients without prior myocardial infarction, the sensitivity for detection of disease was 71 and 73%, respectively, similar for both PET and SPECT. There was no significant difference in diagnostic performance between imaging modalities when 2 different modes of stress (exercise treadmill vs intravenous dipyridamole plus handgrip) were used with SPECT imaging. Thus, Rb-82 PET provides improved specificity compared with Tl-201 SPECT for identifying coronary artery disease, most likely due to the higher photon energy of Rb-82 and attenuation correction provided by PET. However, post-test referral cannot be entirely excluded as a potential explanation for the lower specificity of Tl-201 SPECT.

  7. 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

  8. Primary neuroendocrine carcinoma of breast with liver and bone metastasis detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshak; Shibu, Deepu; Radhakrishnan, Edathuruthy Kalarikal; Shinto, Ajit Sugunan

    2014-01-01

    Cases of primary neuroendocrine carcinoma (NEC) of the breast have been reported, though rare. We report the case of a 45-year-old woman presented with jaundice and evaluated to have liver metastasis from neuroendocrine origin. She underwent whole body positron emission tomography/computed tomography, which showed left breast lesion and bone metastasis. Fine-needle aspiration (FNA) of breast revealed a NEC. A diagnosis of a primary NEC of the breast was rendered with hepatic and bone metastasis. She was treated with peptide receptor radionuclide therapy and is on follow-up. PMID:24591780

  9. Primary neuroendocrine carcinoma of breast with liver and bone metastasis detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshak; Shibu, Deepu; Radhakrishnan, Edathuruthy Kalarikal; Shinto, Ajit Sugunan

    2014-01-01

    Cases of primary neuroendocrine carcinoma (NEC) of the breast have been reported, though rare. We report the case of a 45-year-old woman presented with jaundice and evaluated to have liver metastasis from neuroendocrine origin. She underwent whole body positron emission tomography/computed tomography, which showed left breast lesion and bone metastasis. Fine-needle aspiration (FNA) of breast revealed a NEC. A diagnosis of a primary NEC of the breast was rendered with hepatic and bone metastasis. She was treated with peptide receptor radionuclide therapy and is on follow-up.

  10. Detection of submicron scale cracks and other surface anomalies using positron emission tomography

    DOEpatents

    Cowan, Thomas E.; Howell, Richard H.; Colmenares, Carlos A.

    2004-02-17

    Detection of submicron scale cracks and other mechanical and chemical surface anomalies using PET. This surface technique has sufficient sensitivity to detect single voids or pits of sub-millimeter size and single cracks or fissures of millimeter size; and single cracks or fissures of millimeter-scale length, micrometer-scale depth, and nanometer-scale length, micrometer-scale depth, and nanometer-scale width. This technique can also be applied to detect surface regions of differing chemical reactivity. It may be utilized in a scanning or survey mode to simultaneously detect such mechanical or chemical features over large interior or exterior surface areas of parts as large as about 50 cm in diameter. The technique involves exposing a surface to short-lived radioactive gas for a time period, removing the excess gas to leave a partial monolayer, determining the location and shape of the cracks, voids, porous regions, etc., and calculating the width, depth, and length thereof. Detection of 0.01 mm deep cracks using a 3 mm detector resolution has been accomplished using this technique.

  11. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  12. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  13. 21 CFR 892.1200 - Emission computed tomography system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Emission computed tomography system. 892.1200 Section 892.1200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... system. (a) Identification. An emission computed tomography system is a device intended to detect...

  14. 64Cu-ATSM Hypoxia Positron Emission Tomography for Detection of Conduit Ischemia in an Experimental Rat Esophagectomy Model

    PubMed Central

    Park, Seong Yong; Kang, Won Jun; Cho, Arthur; Chae, Ju Ri; Cho, Ye Lim; Kim, Jung Young; Lee, Ji Woong; Chung, Kyung Young

    2015-01-01

    Background We designed a hypoxia-imaging modality to detect ischemia of the gastric conduit after esophagectomy. Materials and Methods A rat esophagectomy model was created using 12-16-week-old, 300-350 g male Sprague-Dawley rats. In the operation group (n=6), partial gastric devascularization was performed by ligating the left gastric artery and the short gastric arteries and an esophagogastric anastomosis was performed. In the control group (n=6), the esophageal-gastric junction was incised and suturing was performed without gastric devascularization. Positron emission tomography (PET) images were taken using a microPET rodent model scanner, 24 h after the initial operation, after injection of 200 μCi 64Cu-diacetyl-bis (N4-methylsemicarbazone) (64Cu-ATSM) and pimonidazole 120 mg/kg. After microPET imaging, autoradiography and immunohistochemistry were performed. Results The PET image revealed 64Cu-ATSM uptake at the fundus in the operation group 3 h after 64Cu-ATSM injection. The maximum percentage of the injected dose per gram of tissue was higher in the operation group (0.047±0.015 vs. 0.026±0.006, p=0.021). The fundus/liver ratio was also higher in the operation group (0.541±0.126 vs. 0.278±0.049, p=0.002). Upon autoradiography, 64Cu-ATSM uptake was observed in the fundus in the operation group, and was well-correlated to that observed on the PET image. Upon immunohistochemistry, expression of hypoxia-inducible factor 1a and pimonidazole were significantly increased at the fundus and lesser curvature compared to the greater curvature in the operation group. Conclusion Hypoxia PET imaging with 64Cu-ATSM can detect ischemia in a rat esophagectomy model. Further clinical studies are needed to verify whether hypoxia imaging may be useful in humans. PMID:26098420

  15. Spindle cell sarcoma of pulmonary artery mimicking thromboembolism with lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Pattabiraman, Vr; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-10-01

    Pulmonary artery sarcoma (PAS), although rare, must be considered in the differential diagnosis of pulmonary thromboembolism (PTE). This tumor is highly malignant and the prognosis is very poor. As much as the standardized uptake values (SUVs) at fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) have helped in differentiating between benign and malignant tumors, visualization of a low-attenuation filling defect within a pulmonary artery on contrast-enhanced chest computed tomography (CT) can be suggestive of a malignancy, such as PAS, if the lesion shows high FDG uptake at PET. We present a case of PAS that showed high FDG uptake on integrated FDG PET/CT and with lung metastasis. Patient underwent endoscopic bronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA), which confirmed spindle cell sarcoma.

  16. Spindle cell sarcoma of pulmonary artery mimicking thromboembolism with lung metastasis detected in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Pattabiraman, VR; Mehta, Sangita; Mohanan, Vyshakh; Shinto, Ajit Sugunan

    2014-01-01

    Pulmonary artery sarcoma (PAS), although rare, must be considered in the differential diagnosis of pulmonary thromboembolism (PTE). This tumor is highly malignant and the prognosis is very poor. As much as the standardized uptake values (SUVs) at fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) have helped in differentiating between benign and malignant tumors, visualization of a low-attenuation filling defect within a pulmonary artery on contrast-enhanced chest computed tomography (CT) can be suggestive of a malignancy, such as PAS, if the lesion shows high FDG uptake at PET. We present a case of PAS that showed high FDG uptake on integrated FDG PET/CT and with lung metastasis. Patient underwent endoscopic bronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA), which confirmed spindle cell sarcoma. PMID:25400365

  17. Kikuchi Disease with Generalized Lymph Node, Spleen and Subcutaneous Involvement Detected by Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

    PubMed

    Alshammari, Alshaima; Skoura, Evangelia; Kazem, Nafisa; Ashkanani, Rasha

    2016-06-01

    Kikuchi-Fujimoto disease, known as Kikuchi disease, is a rare benign and self-limiting disorder that typically affects the regional cervical lymph nodes. Generalized lymphadenopathy and extranodal involvement are rare. We report a rare case of a 19-year-old female with a history of persistent fever, nausea, and debilitating malaise. Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) revealed multiple hypermetabolic generalized lymph nodes in the cervical, mediastinum, axillary, abdomen and pelvic regions with diffuse spleen, diffuse thyroid gland, and focal parotid involvement, bilaterally. In addition, subcutaneous lesions were noted in the left upper paraspinal and occipital regions. An excisional lymph node biopsy guided by 18F-FDG PET/CT revealed the patient's diagnosis as Kikuchi syndrome. PMID:27277328

  18. Scintillators for positron emission tomography

    SciTech Connect

    Moses, W.W.; Derenzo, S.E.

    1995-09-01

    Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ``ultimate`` scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length ({le} 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times {le} 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so {le}5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ``fully-3D`` cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm.

  19. Bone Positron Emission Tomography with or without CT Is More Accurate than Bone Scan for Detection of Bone Metastasis

    PubMed Central

    Lee, Soo Jin; Kim, Sang Eun

    2013-01-01

    Objective Na18F bone positron emission tomography (bone PET) is a new imaging modality which is useful for the evaluation of bone diseases. Here, we compared the diagnostic accuracies between bone PET and bone scan for the detection of bone metastasis (BM). Materials and Methods Sixteen cancer patients (M:F = 10:6, mean age = 60 ± 12 years) who underwent both bone PET and bone scan were analyzed. Bone PET was conducted 30 minutes after the injection of 370 MBq Na18F, and a bone scan was performed 3 hours after the injection of 1295 MBq 99mTc-hydroxymethylene diphosphonate. Results In the patient-based analysis (8 patients with BM and 8 without BM), the sensitivities of bone PET (100% = 8/8) and bone scan (87.5% = 7/8) were not significantly different (p > 0.05), whereas the specificity of bone PET (87.5% = 7/8) was significantly greater than that of the bone scan (25% = 2/8) (p < 0.05). In the lesion-based analysis (43 lesions in 14 patients; 31 malignant and 12 benign), the sensitivity of bone PET (100% = 31/31) was significantly greater than that of bone scan (38.7% = 12/31) (p < 0.01), and the specificity of bone PET (75.0% = 9/12) was also significantly higher than that of bone scan (8.3% = 1/12) (p < 0.05). The receiver operating characteristic curve analysis showed that bone PET was significantly more accurate than the bone scan in the patient (p = 0.0306) and lesion (p = 0.0001) based analyses. Conclusion Na18F bone PET is more accurate than bone scan for BM evaluation. PMID:23690722

  20. Impact of computed tomography and {sup 18}F-deoxyglucose coincidence detection emission tomography image fusion for optimization of conformal radiotherapy in non-small-cell lung cancer

    SciTech Connect

    Deniaud-Alexandre, Elisabeth; Touboul, Emmanuel . E-mail: emmanuel.touboul@tnn.aphp.fr; Lerouge, Delphine; Grahek, Dany; Foulquier, Jean-Noel; Petegnief, Yolande; Gres, Benoit; El Balaa, Hanna; Keraudy, Katia; Kerrou, Kaldoun; Montravers, Francoise; Milleron, Bernard; Lebeau, Bernard; Talbot, Jean-Noel

    2005-12-01

    Purpose: To report a retrospective study concerning the impact of fused {sup 18}F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and CT images on three-dimensional conformal radiotherapy planning for patients with non-small-cell lung cancer. Methods and Materials: A total of 101 patients consecutively treated for Stage I-III non-small-cell lung cancer were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images, and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define the target volume. Results: {sup 18}F-fluoro-deoxy-D-glucose-PET identified previously undetected distant metastatic disease in 8 patients, making them ineligible for curative conformal radiotherapy (1 patient presented with some positive uptake corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because the fused PET-CT images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT-PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was {>=}25% in 7 patients because CT-PET image fusion reduced the pulmonary GTV in 6 patients (3 patients with atelectasis) and the mediastinal nodal GTV in 1 patient. The GTV increase was {>=}25% in 14 patients owing to an increase in the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Of 81 patients receiving a total dose of {>=}60 Gy at the International Commission on Radiation Units and Measurements point, after CT-PET image fusion, the percentage of total lung volume receiving >20 Gy increased in 15 cases and decreased in 22. The percentage of total heart volume receiving >36 Gy increased in 8

  1. An Extremely Rare Intersection: Neurolymphomatosis in a Patient with Burkitt Lymphoma Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Oner, Ali Ozan; Okuyucu, Kursat; Alagoz, Engin; Battal, Bilal; Arslan, Nuri

    2016-01-01

    Neurolymphomatosis (NL) is a rarely seen neurologic involvement of the systematic lymphoma. Its diagnosis is challenging, and requires biopsy. In cases where biopsy is not appropriate, 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) may aid in diagnosis. Here, we present a 54-year old male patient diagnosed with Burkitt lymphoma who underwent FDG-PET/CT in order to evaluate the treatment response after chemotherapy and radiotherapy. On viewing PET/CT images of the patient who complained of pain and weakness in his upper extremities after therapy, linear FDG uptake was observed in bilateral cervical 5 (C5), left cervical 6 (C6), bilateral cervical 7 (C7), and right lumbar 4 (L4) nerve roots. Magnetic resonance imaging (MRI) revealed dilation and thickening of nerve roots consisted with FDG uptake observed on PET/CT images. Since biopsy was not performed, histopathological diagnosis could not be established. However, overlapping of clinical, PET/CT, and MRI findings strongly suggested the presence of NL. As is the case of this patient, in cases with non-Hodgkin lymphoma, a combined evaluation of FDG-PET/CT and MRI modalities aid in the establishment of the diagnosis of NL. PMID:27651745

  2. An Extremely Rare Intersection: Neurolymphomatosis in a Patient with Burkitt Lymphoma Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

    PubMed

    Oner, Ali Ozan; Okuyucu, Kursat; Alagoz, Engin; Battal, Bilal; Arslan, Nuri

    2016-09-01

    Neurolymphomatosis (NL) is a rarely seen neurologic involvement of the systematic lymphoma. Its diagnosis is challenging, and requires biopsy. In cases where biopsy is not appropriate, 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) may aid in diagnosis. Here, we present a 54-year old male patient diagnosed with Burkitt lymphoma who underwent FDG-PET/CT in order to evaluate the treatment response after chemotherapy and radiotherapy. On viewing PET/CT images of the patient who complained of pain and weakness in his upper extremities after therapy, linear FDG uptake was observed in bilateral cervical 5 (C5), left cervical 6 (C6), bilateral cervical 7 (C7), and right lumbar 4 (L4) nerve roots. Magnetic resonance imaging (MRI) revealed dilation and thickening of nerve roots consisted with FDG uptake observed on PET/CT images. Since biopsy was not performed, histopathological diagnosis could not be established. However, overlapping of clinical, PET/CT, and MRI findings strongly suggested the presence of NL. As is the case of this patient, in cases with non-Hodgkin lymphoma, a combined evaluation of FDG-PET/CT and MRI modalities aid in the establishment of the diagnosis of NL. PMID:27651745

  3. An Extremely Rare Intersection: Neurolymphomatosis in a Patient with Burkitt Lymphoma Detected by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Oner, Ali Ozan; Okuyucu, Kursat; Alagoz, Engin; Battal, Bilal; Arslan, Nuri

    2016-01-01

    Neurolymphomatosis (NL) is a rarely seen neurologic involvement of the systematic lymphoma. Its diagnosis is challenging, and requires biopsy. In cases where biopsy is not appropriate, 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) may aid in diagnosis. Here, we present a 54-year old male patient diagnosed with Burkitt lymphoma who underwent FDG-PET/CT in order to evaluate the treatment response after chemotherapy and radiotherapy. On viewing PET/CT images of the patient who complained of pain and weakness in his upper extremities after therapy, linear FDG uptake was observed in bilateral cervical 5 (C5), left cervical 6 (C6), bilateral cervical 7 (C7), and right lumbar 4 (L4) nerve roots. Magnetic resonance imaging (MRI) revealed dilation and thickening of nerve roots consisted with FDG uptake observed on PET/CT images. Since biopsy was not performed, histopathological diagnosis could not be established. However, overlapping of clinical, PET/CT, and MRI findings strongly suggested the presence of NL. As is the case of this patient, in cases with non-Hodgkin lymphoma, a combined evaluation of FDG-PET/CT and MRI modalities aid in the establishment of the diagnosis of NL.

  4. Diagnostic sensitivity of ¹⁸fluorodeoxyglucose positron emission tomography for detecting synchronous multiple primary cancers in head and neck cancer patients.

    PubMed

    Kondo, Norio; Tsukuda, Mamoru; Nishimura, Goshi

    2012-05-01

    We assessed the sensitivity of positron emission tomography (PET) for detecting synchronous multiple primary cancers, particularly synchronous esophageal cancers in head and neck cancer patients. We retrospectively reviewed 230 head and neck cancer patients. All the patients routinely underwent the following examinations: urinalysis, occult blood, tumor marker detection [squamous cell carcinoma (SCC), cytokeratin fragment (CYFRA), and carcinoembryonic antigen (CEA)], esophagogastroduodenoscopy, colonoscopy (when CEA was high or occult blood was positive), abdominal ultrasonography, plain chest computed tomography (CT), and PET. Bronchoscopy was performed when CT revealed lung shadow of central region. Synchronous multiple primary cancers were detected in 42 (18.2%) patients. The diagnostic sensitivity of PET for synchronous primary cancers was as follows: esophagus, 7.6% (1/13); stomach, 25.0% (2/8); lung, 66.7% (4/6); head and neck, 75.0% (3/4); colon, 0% (0/1); kidney, 0% (0/1); and subcutaneous, 100% (1/1). The sensitivity of PET for detecting synchronous esophageal cancers is low because these are early-stage cancers (almost stage 0-I). Therefore, it is necessary to perform esophagogastroduodenoscopy for detecting synchronous esophageal cancers. PET is an important additional tool for detecting synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous head and neck cancer and lung cancer is high. But PET has the limitation of sensitivity for synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous esophageal cancer is very low.

  5. Positron emission tomography for the assessment of myocardial viability

    SciTech Connect

    Schelbert, H.R. )

    1991-09-01

    The detection of viable myocardium or ischemically injured myocardium with a reversible impairment of contractile function remains clinically important but challenging. Detection of reversible dysfunction and distinction from irreversible tissue injury by positron emission tomography is based on identification of preserved or even enhanced glucose metabolism with F-18 2-fluoro 2-deoxyglucose. Regional patterns of myocardial glucose utilization and blood flow, defined as perfusion-metabolism mismatches or matches, on positron emission tomography in patients with chronic or even acute ischemic heart disease are highly accurate in predicting the functional outcome after interventional revascularization. Compared with thallium-201 redistribution scintigraphy, positron emission tomography appears to be diagnostically more accurate, especially in patients with severely impaired left ventricular function. While larger clinical trials are needed for further confirmation, positron emission tomography has already proved clinically useful for stratifying patients with poor left ventricular function to the most appropriate therapeutic approach.

  6. 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.

  7. Fan Beam Emission Tomography for Laminar Fires

    NASA Technical Reports Server (NTRS)

    Sivathanu, Yudaya; Lim, Jongmook; Feikema, Douglas

    2003-01-01

    Obtaining information on the instantaneous structure of turbulent and transient flames is important in a wide variety of applications such as fire safety, pollution reduction, flame spread studies, and model validation. Durao et al. has reviewed the different methods of obtaining structure information in reacting flows. These include Tunable Laser Absorption Spectroscopy, Fourier Transform Infrared Spectroscopy, and Emission Spectroscopy to mention a few. Most flames emit significant radiation signatures that are used in various applications such as fire detection, light-off detection, flame diagnostics, etc. Radiation signatures can be utilized to maximum advantage for determining structural information in turbulent flows. Emission spectroscopy is most advantageous in the infrared regions of the spectra, principally because these emission lines arise from transitions in the fundamental bands of stable species such as CO2 and H2O. Based on the above, the objective of this work was to develop a fan beam emission tomography system to obtain the local scalar properties such as temperature and mole fractions of major gas species from path integrated multi-wavelength infrared radiation measurements.

  8. Compact conscious animal positron emission tomography scanner

    DOEpatents

    Schyler, David J.; O'Connor, Paul; Woody, Craig; Junnarkar, Sachin Shrirang; Radeka, Veljko; Vaska, Paul; Pratte, Jean-Francois; Volkow, Nora

    2006-10-24

    A method of serially transferring annihilation information in a compact positron emission tomography (PET) scanner includes generating a time signal for an event, generating an address signal representing a detecting channel, generating a detector channel signal including the time and address signals, and generating a composite signal including the channel signal and similarly generated signals. The composite signal includes events from detectors in a block and is serially output. An apparatus that serially transfers annihilation information from a block includes time signal generators for detectors in a block and an address and channel signal generator. The PET scanner includes a ring tomograph that mounts onto a portion of an animal, which includes opposing block pairs. Each of the blocks in a block pair includes a scintillator layer, detection array, front-end array, and a serial encoder. The serial encoder includes time signal generators and an address signal and channel signal generator.

  9. Single Photon Emission Computed Tomography (SPECT)

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Single Photon Emission Computed Tomography (SPECT) Updated:Sep 11,2015 ... Persantine) or dobutamine. The tests may take between 2 and 2 1/2 hours. What happens after ...

  10. Estimation of linear functionals in emission tomography

    SciTech Connect

    Kuruc, A.

    1995-08-01

    In emission tomography, the spatial distribution of a radioactive tracer is estimated from a finite sample of externally-detected photons. We present an algorithm-independent theory of statistical accuracy attainable in emission tomography that makes minimal assumptions about the underlying image. Let f denote the tracer density as a function of position (i.e., f is the image being estimated). We consider the problem of estimating the linear functional {Phi}(f) {triple_bond} {integral}{phi}(x)f(x) dx, where {phi} is a smooth function, from n independent observations identically distributed according to the Radon transform of f. Assuming only that f is bounded above and below away from 0, we construct statistically efficient estimators for {Phi}(f). By definition, the variance of the efficient estimator is a best-possible lower bound (depending on and f) on the variance of unbiased estimators of {Phi}(f). Our results show that, in general, the efficient estimator will have a smaller variance than the standard estimator based on the filtered-backprojection reconstruction algorithm. The improvement in performance is obtained by exploiting the range properties of the Radon transform.

  11. Improved photomultiplier tube for positron emission tomography.

    PubMed

    Woldeselassie, T

    1989-05-01

    The paper describes an investigation in which it is shown that small positive voltage pulses applied to an external conductor placed against the photocathode of a photomultiplier tube can be used to switch the photocathode completely off for the duration of the pulses. This suggests that a photomultiplier tube with a multisegment photocathode can be constructed, the individual cathode segments of which can be switched off independently by means of such pulses. A theoretical explanation for the effect is provided with the aid of a simple circuit model for the photocathode. Analysis of the model also shows that it is possible to identify the particular cathode segment in which a photon is detected when a pulse is recorded at the phototube's anode. A phototube with these characteristics can have important implications for positron emission tomography, as it can provide improved spatial resolution, simultaneous multislice capability and the ability to eliminate distortion due to dead-time effects at high count rates.

  12. A BGO/GSO position sensitive block detector for a high resolution positron emission tomography with depth of interaction detection capability

    SciTech Connect

    Yamamoto, S.

    1996-12-31

    We developed a position sensitive block detector with depth of interaction detection capability for positron emission tomography (PET). The detector consists of 6 x 8 array of GSO scintillators, 6 x 8 array of BGO scintillators and two dual photomultiplier tubes (PMT). The GSO scintillators are optically coupled to front surface of the BGO scintillators. The position of 6 x 8 scintillators are determined by the Anger principle and depth of interaction position is determined by using the pulse shape analysis of GSOs and BGOs. Performance of the block detector was measured. Position distribution of the developed BGO/GSO block detector was little distorted. However the separation of the spots was still enough to distinguish the scintillators in transaxial and axial directions. Since pulse shape distribution using a developed simple pulse shape analyzer had two peaks, it is possible to separate the GSOs and BGOs for depth of interaction detection. With these results, a high resolution PET with depth of interaction detection capability will be possible using the developed BGO/GSO block detectors.

  13. Recent Developments in Positron Emission Tomography (PET) Instrumentation

    DOE R&D Accomplishments Database

    Derenzo, S. E.; Budinger, T. F.

    1986-04-01

    This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors.

  14. Data analysis in emission tomography using emission-count posteriors

    NASA Astrophysics Data System (ADS)

    Sitek, Arkadiusz

    2012-11-01

    A novel approach to the analysis of emission tomography data using the posterior probability of the number of emissions per voxel (emission count) conditioned on acquired tomographic data is explored. The posterior is derived from the prior and the Poisson likelihood of the emission-count data by marginalizing voxel activities. Based on emission-count posteriors, examples of Bayesian analysis including estimation and classification tasks in emission tomography are provided. The application of the method to computer simulations of 2D tomography is demonstrated. In particular, the minimum-mean-square-error point estimator of the emission count is demonstrated. The process of finding this estimator can be considered as a tomographic image reconstruction technique since the estimates of the number of emissions per voxel divided by voxel sensitivities and acquisition time are the estimates of the voxel activities. As an example of a classification task, a hypothesis stating that some region of interest (ROI) emitted at least or at most r-times the number of events in some other ROI is tested. The ROIs are specified by the user. The analysis described in this work provides new quantitative statistical measures that can be used in decision making in diagnostic imaging using emission tomography.

  15. A comparison of rest sestamibi and rest-redistribution thallium single photon emission tomography: possible implications for myocardial viability detection in infarcted patients.

    PubMed

    Dondi, M; Tartagni, F; Fallani, F; Fanti, S; Marengo, M; DiTommaso, I; Zheng, Q F; Monetti, N

    1993-01-01

    Thirty patients (26 men, 4 women, mean age 61 +/- 8 years) who had suffered myocardial infarction 15 +/- 6 months previously, were submitted to (1) standard stress-redistribution thallium-201 single photon emission tomography (SPET), (2) rest-redistribution 201T1 SPET and (3) stress-rest technetium-99m sestamibi SPET. Uptake modifications in relation to exercise-induced defects were evaluated in a total of 390 myocardial segments. Tracer uptake was scored as normal (=0), mildly reduced (=1), apparently reduced (=2), severely reduced (=3) or absent (=4). Comparison of stress studies failed to show any statistical difference (58% segmental abnormalities with sestamibi vs 61% with thallium). Uptake abnormalities (score 1-4) were detected in 55% of the segments with sestamibi, 55% with standard thallium redistribution, 55% with early imaging after thallium injection at rest and 54% with 3-h delayed rest imaging (P = NS). Absence of tracer uptake (score = 4) under resting conditions was recorded in 75 (19%) segments with standard 201T1 redistribution, 75 (19%) with rest sestamibi, 70 (18%) with rest 201T1 imaging and 62 (16%) with rst-redistribuion 201T1 (P < 0.05 vs other imaging modalities). Thus, 3-h delayed rest thallium imaging detected reversibility of uptake defects in a significantly higher number of myocardial segments. This finding might have important implications for both tracer and technique selection when myocardial viability is the main clinical issue.

  16. Comparison of Positron Emission Tomography Scanning and Sentinel Node Biopsy in the Detection of Inguinal Node Metastases in Patients With Anal Cancer

    SciTech Connect

    Mistrangelo, Massimiliano; Pelosi, Ettore; Bello, Marilena; Castellano, Isabella; Cassoni, Paola; Ricardi, Umberto; Munoz, Fernando; Racca, Patrizia; Contu, Viviana; Beltramo, Giancarlo; Morino, Mario; Mussa, Antonio

    2010-05-01

    Background: Inguinal lymph node metastases in patients with anal cancer are an independent prognostic factor for local failure and overall mortality. Inguinal lymph node status can be adequately assessed with sentinel node biopsy, and the radiotherapy strategy can subsequently be changed. We compared this technique vs. dedicated 18F-fluorodeoxyglucose positron emission tomography (PET) to determine which was the better tool for staging inguinal lymph nodes. Methods and Materials: In our department, 27 patients (9 men and 18 women) underwent both inguinal sentinel node biopsy and PET-CT. PET-CT was performed before treatment and then at 1 and 3 months after treatment. Results: PET-CT scans detected no inguinal metastases in 20 of 27 patients and metastases in the remaining 7. Histologic analysis of the sentinel lymph node detected metastases in only three patients (four PET-CT false positives). HIV status was not found to influence the results. None of the patients negative at sentinel node biopsy developed metastases during the follow-up period. PET-CT had a sensitivity of 100%, with a negative predictive value of 100%. Owing to the high number of false positives, PET-CT specificity was 83%, and positive predictive value was 43%. Conclusions: In this series of patients with anal cancer, inguinal sentinel node biopsy was superior to PET-CT for staging inguinal lymph nodes.

  17. 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

    2015-02-01

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

  18. Positron Emission Tomography: A Basic Analysis

    NASA Astrophysics Data System (ADS)

    Kerbacher, M. E.; Deaton, J. W.; Phinney, L. C.; Mitchell, L. J.; Duggan, J. L.

    2007-10-01

    Positron Emission Tomography is useful in detecting biological abnormalities. The technique involves attaching radiotracers to a material used inside the body, in many cases glucose. Glucose is absorbed most readily in areas of unusual cell growth or uptake of nutrients so through natural processes the treated glucose highlights regions of tumors and other degenerative disorders such as Alzheimer's disease. The higher the concentration of isotopes, the more dynamic the area. Isotopes commonly used as tracers are 11C, 18F, 13N, and 15O due to their easy production and short half-lives. Once the tracers have saturated an area of tissue they are detected using coincidence detectors collinear with individual isotopes. As the isotope decays it emits a positron which, upon annihilating an electron, produces two oppositely directioned gamma rays. The PET machine consists of several pairs of detectors, each 180 degrees from their partner detector. When the oppositely positioned detectors are collinear with the area of the isotope, a computer registers the location of the isotope and can compile an image of the activity of the highlighted area based on the position and strength of the isotopes.

  19. Advanced Instrumentation for Positron Emission Tomography [PET

    DOE R&D Accomplishments Database

    Derenzo, S. E.; Budinger, T. F.

    1985-04-01

    This paper summarizes the physical processes and medical science goals that underlay modern instrumentation design for Positron Emission Tomography. The paper discusses design factors such as detector material, crystalphototube coupling, shielding geometry, sampling motion, electronics design, time-of-flight, and the interrelationships with quantitative accuracy, spatial resolution, temporal resolution, maximum data rates, and cost.

  20. Evaluation of cancer detection with whole-body positron emission tomography (PET) and 2-[F-18]fluoro-2-deoxy-D-glucose

    NASA Astrophysics Data System (ADS)

    Hoh, Carl K.; Hawkins, Randall A.; Glaspy, John A.; Dahlbom, Magnus; Tse, Nielson Y.; Hoffman, Edward T.; Schiepers, Christiaan; Choi, Yong; Rege, Sheila; Nitzsche, Egbert U.; Maddahi, Jamshid; Phelps, Michael E.

    1993-08-01

    Until recently, positron emission tomography (PET) has been acquired and displayed in a standard transaxial image format. The development of whole body PET has allowed biochemical and physiologic imaging of the entire body, expanding the limited axial field of view of the conventional PET scanner. In this study, the application of whole body PET studies with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) for tumor imaging was evaluated. Whole body PET studies were positive (presence of focal FDG uptake relative to surrounding tissue activity) in 61 of 70 patients (87%) with biopsy confirmed malignant tumors. PET images failed to reveal focal hypermetabolism in 9 of the 70 patients. Of the 17 patients with benign biopsies lesions, 13 patients had whole body PET studies without focal areas of FDG uptake. Because of the high glycolytic rate of malignant tissue, the whole body PET FDG technique has promise in the detection of a wide variety of both primary and metastatic malignancies. The presence of FDG uptake in benign inflammatory conditions may limit the specificity of the technique. The true positive rates for the characterization of known lesions was 87% in this series, and the PET FDG method is promising both in determining both the nature of a localized lesion, and in defining the systemic extent of malignant disease.

  1. [F-18]-Fluoro-2-deoxy-D-glucose positron emission tomography as a tool for early detection of immunotherapy response in a murine B cell lymphoma model

    PubMed Central

    Chaise, Coralie; Itti, Emmanuel; Petegnief, Yolande; Wirquin, Evelyne; Copie-Bergman, Christiane; Farcet, Jean-Pierre; Delfau-Larue, Marie-Hélène; Meignan, Michel; Talbot, Jean-Noël; Molinier-Frenkel, Valérie

    2007-01-01

    [F-18]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is a non-invasive imaging technique which has recently been validated for the assessment of therapy response in patients with aggressive non-Hodgkin’s lymphoma. Our objective was to determine its value for the evaluation of immunotherapy efficacy in immunocompetent Balb/c mice injected with the A20 syngeneic B lymphoma cell line. The high level of in vitro FDG uptake by A20 cells validated the model for further imaging studies. When injected intravenously, the tumour developed as nodular lesions mostly in liver and spleen, thus mimicking the natural course of an aggressive human lymphoma. FDG-PET provided three-dimensionnal images of tumour extension including non palpable lesions, in good correlation with ex-vivo macroscopic examination. When mice were pre-immunized with an A20 cell lysate in adjuvant before tumour challenge, their significantly longer survival, compared to control mice, was associated with a lower incidence of lymphoma visualized by PET at different time points. Estimation of tumour growth and metabolism using the calculated tumour volumes and maximum standardized uptake values respectively, also demonstrated delayed lymphoma development and lower activity in the vaccinated mice. Thus, FDG-PET is a sensitive tool relevant for early detection and follow-up of internal tumours, allowing discrimination between treated and non-treated small animal cohorts without invasive intervention. PMID:17171356

  2. Positron emission tomography - a new approach to brain chemistry

    SciTech Connect

    Jacobson, H.G.

    1988-11-11

    Positron emission tomography permits examination of the chemistry of the brain in living beings. Until recently, positron emission tomography had been considered a research tool, but it is rapidly moving into clinical practice. This report describes the uses and applications of positron emission tomography in examinations of patients with strokes, epilepsy, malignancies, dementias, and schizophrenia and in basic studies of synaptic neurotransmission.

  3. Positron emission tomography in generalized seizures

    SciTech Connect

    Theodore, W.H.; Brooks, R.; Margolin, R.; Patronas, N.; Sato, S.; Porter, R.J.; Mansi, L.; Bairamian, D.; DiChiro, G.

    1985-05-01

    The authors used /sup 18/F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to study nine patients with clinical absence or generalized seizures. One patient had only absence seizures, two had only generalized tonic-clonic seizures, and six had both seizure types. Interictal scans in eight failed to reveal focal or lateralized hypometabolism. No apparent abnormalities were noted. Two patients had PET scans after isotope injection during hyperventilation-induced generalized spike-wave discharges. Diffusely increased metabolic rates were found in one compared with an interictal scan, and in another compared with control values. Another patient had FDG injected during absence status: EEG showed generalized spike-wave discharges (during which she was unresponsive) intermixed with slow activity accompanied by confusion. Metabolic rates were decreased, compared with the interictal scan, throughout both cortical and subcortical structures. Interictal PET did not detect specific anatomic regions responsible for absence seizure onset in any patient, but the results of the ictal scans did suggest that pathophysiologic differences exist between absence status and single absence attacks.

  4. Detection and Assessment Using Positron Emission Tomography of Genetically Determined Defects in Myocardial Fatty Acid Utilization. Final report, 8/1/93-6/30/97

    SciTech Connect

    Bergmann, Steven R.

    2000-04-09

    An approach using positron emission tomography (PET) was developed, validated and used to measure myocardial fatty acid metabolism in patients with inherited forms of heart failure. Abnormalities were correlated with the severity of the clinical illness. The approach developed was also shown to identify abnormalities in myocardial fatty acid metabolism in some patients with acquired forms of heart failure. The PET technique thus permits identification of abnormal fatty acid metabolism and provides an approach to evaluate the efficacy of interventional strategies.

  5. [Assessing myocardial perfusion with positron emission tomography].

    PubMed

    vom Dahl, J

    2001-11-01

    Positron emission tomography (PET) of the heart has gained widespread scientific and clinical acceptance with regard to two indications: 1) The detection of perfusion abnormalities by qualitative and semiquantitative analyses of perfusion images at rest and during physical or pharmacological stress using well-validated perfusion tracers, such as N-13 ammonia, Rb-82 rubidium chloride, or O-15 labeled water. 2) Viability imaging of myocardial regions with reduced contractility by combining perfusion measurements with substrate metabolism as assessed from F-18 deoxyglucose utilization. This overview summarizes the use of PET as a perfusion imaging method. With a sensitivity > 90% in combination with high specificity, PET is today the best-validated available nuclear imaging technique for the diagnosis of coronary artery disease (CAD). The short half-life of the perfusion tracers in combination with highly sophisticated hard- and software enables rapid PET studies with high patient throughput. The high diagnostic accuracy and the methological advantages as compared to conventional scintigraphy allows one to use PET perfusion imaging to detect subtle changes in the perfusion reserve for the detection of CAD in high risk but asymptomatic patients as well as in patients with proven CAD undergoing various treatment forms such as risk factor reduction or coronary revascularization. In patients following orthotopic heart transplantation, evolving transplant vasculopathy can be detected at an early stage. Quantitative PET imaging at rest allows for detection of myocardial viability since cellular survival is based on maintenance of a minimal perfusion and structural changes correlate to the degree of perfusion reduction. Furthermore, quantitative assessment of the myocardial perfusion reserve detects the magnitude and competence of collaterals in regions with occluded epicardial collaterals and, thus, imaging of several coronary distribution territories in one noninvasive

  6. Positron emission tomography tracers for imaging angiogenesis

    PubMed Central

    Beer, Ambros J.; Wang, Hui; Chen, Xiaoyuan

    2013-01-01

    Position emission tomography imaging of angiogenesis may provide non-invasive insights into the corresponding molecular processes and may be applied for individualized treatment planning of antiangiogenic therapies. At the moment, most strategies are focusing on the development of radiolabelled proteins and antibody formats targeting VEGF and its receptor or the ED-B domain of a fibronectin isoform as well as radiolabelled matrix metalloproteinase inhibitors or αvβ3 integrin antagonists. Great efforts are being made to develop suitable tracers for different target structures. All of the major strategies focusing on the development of radiolabelled compounds for use with positron emission tomography are summarized in this review. However, because the most intensive work is concentrated on the development of radiolabelled RGD peptides for imaging αvβ3 expression, which has successfully made its way from bench to bedside, these developments are especially emphasized. PMID:20559632

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

    PubMed

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

    2001-01-01

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

  8. Positron emission tomography imaging of prostate cancer

    PubMed Central

    Hong, Hao; Zhang, Yin; Sun, Jiangtao; Cai, Weibo

    2009-01-01

    Prostate cancer (PCa) is the second leading cause of cancer death among men in the United States. Positron emission tomography (PET), a non-invasive, sensitive, and quantitative imaging technique, can facilitate personalized management of PCa patients. There are two critical needs for PET imaging of PCa, early detection of primary lesions and accurate imaging of PCa bone metastasis, the predominant cause of death in PCa. Since the most widely used PET tracer in the clinic, 18F-fluoro-2-deoxy-2-D-glucose (18F-FDG), does not meet these needs, a wide variety of PET tracers have been developed for PCa imaging which span an enormous size range from small molecules to intact antibodies. In this review, we will first summarize small molecule-based PET tracers for PCa imaging, which measure certain biological events such as cell membrane metabolism, fatty acid synthesis, and receptor expression. Next, we will discuss radiolabeled amino acid derivatives (e.g. methionine, leucine, tryptophan, and cysteine analogs), which are primarily based on the increased amino acid transport of PCa cells. Peptide-based tracers for PET imaging of PCa, mostly based on the bombesin peptide and its derivatives which bind to the gastrin-releasing peptide receptor, will then be presented in detail. We will also cover radiolabeled antibodies and antibody fragments (e.g. diabodies and minibodies) for PET imaging of PCa, targeting integrin αvβ3, EphA2, the epidermal growth factor receptor, or the prostate stem cell antigen. Lastly, we will identify future directions for the development of novel PET tracers for PCa imaging, which may eventually lead to personalized management of PCa patients. PMID:19946787

  9. 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

  10. Therapy response evaluation with positron emission tomography-computed tomography.

    PubMed

    Segall, George M

    2010-12-01

    Positron emission tomography-computed tomography with F-18-fluorodeoxyglucose is widely used for evaluation of therapy response in patients with solid tumors but has not been as readily adopted in clinical trials because of the variability of acquisition and processing protocols and the absence of universal response criteria. Criteria proposed for clinical trials are difficult to apply in clinical practice, and gestalt impression is probably accurate in individual patients, especially with respect to the presence of progressive disease and complete response. Semiquantitative methods of determining tissue glucose metabolism, such as standard uptake value, can be a useful descriptor for levels of tissue glucose metabolism and changes in response to therapy if technical quality control measures are carefully maintained. The terms partial response, complete response, and progressive disease are best used in clinical trials in which the terms have specific meanings and precise definitions. In clinical practice, it may be better to use descriptive terminology agreed upon by imaging physicians and clinicians in their own practice. PMID:21147376

  11. Positron Emission Tomography: Principles, Technology, and Recent Developments

    NASA Astrophysics Data System (ADS)

    Ziegler, Sibylle I.

    2005-04-01

    Positron emission tomography (PET) is a nuclear medical imaging technique for quantitative measurement of physiologic parameters in vivo (an overview of principles and applications can be found in [P.E. Valk, et al., eds. Positron Emission Tomography. Basic Science and Clinical Practice. 2003, Springer: Heidelberg]), based on the detection of small amounts of posi-tron-emitter-labelled biologic molecules. Various radiotracers are available for neuro-logical, cardiological, and oncological applications in the clinic and in research proto-cols. This overview describes the basic principles, technology, and recent develop-ments in PET, followed by a section on the development of a tomograph with ava-lanche photodiodes dedicated for small animal imaging as an example of efforts in the domain of high resolution tomographs.

  12. 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.

  13. Positron Emission Tomography: Its 65 years

    NASA Astrophysics Data System (ADS)

    Del Guerra, A.; Belcari, N.; Bisogni, M.

    2016-04-01

    Positron Emission Tomography (PET) is a well-established imaging technique for in vivo molecular imaging. In this review after a brief history of PET there are presented its physical principles and the technology that has been developed for bringing PET from a bench experiment to a clinical indispensable instrument. The limitations and performance of the PET tomographs are discussed, both as for the hardware and software aspects. The status of art of clinical, pre-clinical and hybrid scanners (, PET/CT and PET/MR) is reported. Finally the actual trend and the recent and future technological developments are fully illustrated.

  14. Mediastinal lymph node staging of non-small-cell lung cancer: a prospective comparison of computed tomography and positron emission tomography.

    PubMed

    Scott, W J; Gobar, L S; Terry, J D; Dewan, N A; Sunderland, J J

    1996-03-01

    We compared the abilities of positron emission tomography and computed tomography to detect N2 or N3 lymph node metastases (N2 or N3) in patients with lung cancer. Positron emission tomography detects increased rates of glucose uptake, characteristic of malignant cells. Patients with peripheral tumors smaller than 2 cm and a normal mediastinum were ineligible. All patients underwent computed tomography, positron emission tomography, and surgical staging. The American Thoracic Society lymph node map was used. Computed and positron emission tomographic scans were read by separate radiologists blinded to surgical staging results. Lymph nodes were "positive" by computed tomography if larger than 1.0 cm in short-axis diameter. Standardized uptake values were recorded from areas on positron emission tomography corresponding to those from which biopsy specimens were taken; if greater than 4.2, they were called "positive." Seventy-five lymph node stations (2.8 per patient) were analyzed in 27 patients. Computed tomography incorrectly staged the mediastinum as positive for metastases in three patients and as negative for metastases in three patients. Sensitivity and specificity of computed tomographic scans were 67% and 83%, respectively. Positron emission tomography correctly staged the mediastinum in all 27 patients. When analyzed by individual node station, there were four false positive and four false negative results by computed tomography (sensitivity = 60%, specificity = 93%, positive predictive value = 60%). Positron emission tomography mislabeled one node station as positive (100% sensitive, 98% specific, positive predictive value 91%). The differences were significant when the data were analyzed both for individual lymph node stations (p = 0.039) and for patients (p = 0.031) (McNemar test). Positron emission tomography and computed tomography are more accurate than computed tomography alone in detecting mediastinal lymph node metastases from non-small-cell lung

  15. Direct conversion semiconductor detectors in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Cates, Joshua W.; Gu, Yi; Levin, Craig S.

    2015-05-01

    Semiconductor detectors are playing an increasing role in ongoing research to improve image resolution, contrast, and quantitative accuracy in preclinical applications of positron emission tomography (PET). These detectors serve as a medium for direct detection of annihilation photons. Early clinical translation of this technology has shown improvements in image quality and tumor delineation for head and neck cancers, relative to conventional scintillator-based systems. After a brief outline of the basics of PET imaging and the physical detection mechanisms for semiconductor detectors, an overview of ongoing detector development work is presented. The capabilities of semiconductor-based PET systems and the current state of these devices are discussed.

  16. Level Set Method for Positron Emission Tomography

    PubMed Central

    Chan, Tony F.; Li, Hongwei; Lysaker, Marius; Tai, Xue-Cheng

    2007-01-01

    In positron emission tomography (PET), a radioactive compound is injected into the body to promote a tissue-dependent emission rate. Expectation maximization (EM) reconstruction algorithms are iterative techniques which estimate the concentration coefficients that provide the best fitted solution, for example, a maximum likelihood estimate. In this paper, we combine the EM algorithm with a level set approach. The level set method is used to capture the coarse scale information and the discontinuities of the concentration coefficients. An intrinsic advantage of the level set formulation is that anatomical information can be efficiently incorporated and used in an easy and natural way. We utilize a multiple level set formulation to represent the geometry of the objects in the scene. The proposed algorithm can be applied to any PET configuration, without major modifications. PMID:18354724

  17. Imaging local brain function with emission computed tomography

    SciTech Connect

    Kuhl, D.E.

    1984-03-01

    Positron emission tomography (PET) using /sup 18/F-fluorodeoxyglucose (FDG) was used to map local cerebral glucose utilization in the study of local cerebral function. This information differs fundamentally from structural assessment by means of computed tomography (CT). In normal human volunteers, the FDG scan was used to determine the cerebral metabolic response to conrolled sensory stimulation and the effects of aging. Cerebral metabolic patterns are distinctive among depressed and demented elderly patients. The FDG scan appears normal in the depressed patient, studded with multiple metabolic defects in patients with multiple infarct dementia, and in the patients with Alzheimer disease, metabolism is particularly reduced in the parietal cortex, but only slightly reduced in the caudate and thalamus. The interictal FDG scan effectively detects hypometabolic brain zones that are sites of onset for seizures in patients with partial epilepsy, even though these zones usually appear normal on CT scans. The future prospects of PET are discussed.

  18. RPC: from High Energy Physics to Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Belli, G.; DeVecchi, C.; Giroletti, E.; Musitelli, G.; Nardò, R.; Necchi, M. M.; Pagano, D.; Ratti, S. P.; Riccardi, C.; Sani, G.; Torre, P.; Vitulo, P.; Viviani, C.

    2006-05-01

    A low cost gas-based charged particle detector, the Resistive Plate Counter (RPC) intensively used in fixed target and collider high energy experiments, is proposed as basic detector for Positron Emission Tomography. The performance of RPCs in terms of intrinsic space and time resolution and electronic pulse height response, makes it possible to transform standard RPCs into photon detectors and therefore to compensate for the photon sensitivity of scintillating crystals, when the efficiency of the complex crystal + photomultiplier is turned into standard quantum efficiency (q.e). Prototype multigap glass RPCs were developed which optimize γ detection efficiency and thus might substitute the traditional scintillators setups.

  19. [Positron emission tomography: a new modality in Brazilian nuclear medicine].

    PubMed

    Robilotta, Cecil Chow

    2006-01-01

    In nuclear medicine, radioactive substances are used to diagnose and treat disease. This medical specialty, that can provide information about the human body's physiologic and metabolic processes, has become a key diagnostic tool for the early detection of many different disorders, including various types of cancer. The present article describes the historical milestones in nuclear medicine; the basic physical principles underlying positron emission tomography (PET), which is an imaging method used to map the distribution of radiopharmaceuticals in the body for diagnostic and therapeutic purposes, and the current status of this modality in Brazil.

  20. Positron Emission Tomography with improved spatial resolution

    SciTech Connect

    Drukier, A.K.

    1990-04-01

    Applied Research Corporation (ARC) proposed the development of a new class of solid state detectors called Superconducting Granular Detectors (SGD). These new detectors permit considerable improvements in medical imaging, e.g. Positron Emission Tomography (PET). The biggest impact of this technique will be in imaging of the brain. It should permit better clinical diagnosis of such important diseases as Altzheimer's or schizophrenia. More specifically, we will develop an improved PET-imager; a spatial resolution 2 mm may be achievable with SGD. A time-of-flight capability(t {approx} 100 psec) will permit better contrast and facilitate 3D imaging. In the following, we describe the results of the first 9 months of the development.

  1. Positron Emission Tomography of the Heart

    DOE R&D Accomplishments Database

    Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

    1979-01-01

    Positron emission computed tomography (PCT) represents an important new tool for the noninvasive evaluation and, more importantly, quantification of myocardial performance. Most currently available techniques permit assessment of only one aspect of cardiac function, i.e., myocardial perfusion by gamma scintillation camera imaging with Thallium-201 or left ventricular function by echocardiography or radionuclide angiocardiography. With PCT it may become possible to study all three major segments of myocardial performance, i.e., regional blood flow, mechanical function and, most importantly, myocardial metabolism. Each of these segments can either be evaluated separately or in combination. This report briefly describes the principles and technological advantages of the imaging device, reviews currently available radioactive tracers and how they can be employed for the assessment of flow, function and metabolism; and, lastly, discusses possible applications of PCT for the study of cardiac physiology or its potential role in the diagnosis of cardiac disease.

  2. Imaging Tumor Metabolism Using Positron Emission Tomography

    PubMed Central

    Lewis, David Y.; Soloviev, Dmitry; Brindle, Kevin M.

    2015-01-01

    Positron emission tomography (PET) is an extraordinarily sensitive clinical imaging modality for interrogating tumor metabolism. Radiolabelled PET substrates can be traced at sub-physiological concentrations, allowing non-invasive imaging of metabolism and intra-tumoral heterogeneity in systems ranging from advanced cancer models to cancer patients in the clinic. There are a wide range of novel and more established PET radiotracers, which can be used to investigate various aspects of tumor metabolism, including carbohydrate, amino acid and fatty acid metabolism. In this review we will briefly discuss the more established metabolic tracers and describe recent work on the development of new tracers. Some of the unanswered questions in tumor metabolism will be considered alongside new technical developments, such as combined PET/MRI machines, that could provide new imaging solutions to some of the outstanding diagnostic challenges facing modern cancer medicine. PMID:25815854

  3. Bayesian image reconstruction: Application to emission tomography

    SciTech Connect

    Nunez, J.; Llacer, J.

    1989-02-01

    In this paper we propose a Maximum a Posteriori (MAP) method of image reconstruction in the Bayesian framework for the Poisson noise case. We use entropy to define the prior probability and likelihood to define the conditional probability. The method uses sharpness parameters which can be theoretically computed or adjusted, allowing us to obtain MAP reconstructions without the problem of the grey'' reconstructions associated with the pre Bayesian reconstructions. We have developed several ways to solve the reconstruction problem and propose a new iterative algorithm which is stable, maintains positivity and converges to feasible images faster than the Maximum Likelihood Estimate method. We have successfully applied the new method to the case of Emission Tomography, both with simulated and real data. 41 refs., 4 figs., 1 tab.

  4. Positron emission tomography features of hidradenitis suppurativa

    PubMed Central

    Simpson, R C; Dyer, M J S; Entwisle, J; Harman, K E

    2011-01-01

    A 35-year-old male with classical Hodgkin's lymphoma (nodular sclerosing, grade 1 histology, clinical stage 2A) underwent a positron emission tomography (PET) scan to assess response to treatment. Half body CT PET imaging was obtained using a Siemens Biograph scanner from eyes to thighs. 405 MBq of 18-fluorodeoxyglucose (FDG) was injected with acquisition starting at 60 min. There was unexpected intense focal uptake in the superficial subcutaneous tissues of the abdomen, pelvis and lateral chest wall with overlying skin thickening seen on the CT component. This was initially of concern, but the patient was known to have a history of hidradenitis suppurativa (HS). On further examination, the radiological abnormalities corresponded to the clinical sites of involvement. To the best of our knowledge, this is the first documentation of the appearance of HS on PET scan. PMID:21750134

  5. Positron emission tomography and radiation oncology

    NASA Astrophysics Data System (ADS)

    Fullerton, PhD, Gary D.; Fox, MD, Peter; Phillips, MD, William T.

    2001-10-01

    Medical physics research is providing new avenues for addressing the fundamental problem of radiation therapy-how to provide a tumor-killing dose while reducing the dose to a non-lethal level for critical organs in adjacent portions of the patient anatomy. This talk reviews the revolutionary impact of Positron Emission Tomography on the practice of radiation oncology. The concepts of PET imaging and the development of "tumor" imaging methods using 18F-DG flouro-deoxyglucose are presented to provide the foundation for contemporary research and application to therapy. PET imaging influences radiation therapy decisions in multiple ways. Imaging of occult but viable tumor metastases eliminates misguided therapy attempts. The ability to distinguish viable tumor from scar tissue and necroses allows reduction of treatment portals and more selective treatments. Much research remains before the clinical benefits of these advances are fully realized.

  6. Positron emission tomography provides molecular imaging of biological processes

    PubMed Central

    Phelps, Michael E.

    2000-01-01

    Diseases are biological processes, and molecular imaging with positron emission tomography (PET) is sensitive to and informative of these processes. This is illustrated by detection of biological abnormalities in neurological disorders with no computed tomography or MRI anatomic changes, as well as even before symptoms are expressed. PET whole body imaging in cancer provides the means to (i) identify early disease, (ii) differentiate benign from malignant lesions, (iii) examine all organs for metastases, and (iv) determine therapeutic effectiveness. Diagnostic accuracy of PET is 8–43% higher than conventional procedures and changes treatment in 20–40% of the patients, depending on the clinical question, in lung and colorectal cancers, melanoma, and lymphoma, with similar findings in breast, ovarian, head and neck, and renal cancers. A microPET scanner for mice, in concert with human PET systems, provides a novel technology for molecular imaging assays of metabolism and signal transduction to gene expression, from mice to patients: e.g., PET reporter gene assays are used to trace the location and temporal level of expression of therapeutic and endogenous genes. PET probes and drugs are being developed together—in low mass amounts, as molecular imaging probes to image the function of targets without disturbing them, and in mass amounts to modify the target's function as a drug. Molecular imaging by PET, optical technologies, magnetic resonance imaging, single photon emission tomography, and other technologies are assisting in moving research findings from in vitro biology to in vivo integrative mammalian biology of disease. PMID:10922074

  7. Concurrent Ultrasonic Tomography and Acoustic Emission in Solid Materials

    NASA Astrophysics Data System (ADS)

    Chow, Thomas M.

    A series of experiments were performed to detect stress induced changes in the elastic properties of various solid materials. A technique was developed where these changes were monitored concurrently by two methods, ultrasonic tomography and acoustic emission monitoring. This thesis discusses some experiments in which acoustic emission (AE) and ultrasonic tomography were performed on various samples of solid materials including rocks, concrete, metals, and fibre reinforced composites. Three separate techniques were used to induce stress in these samples. Disk shaped samples were subject to stress via diametral loading using an indirect tensile test geometry. Cylindrical samples of rocks and concrete were subject to hydraulic fracture tests, and rectangular samples of fibre reinforced composite were subject to direct tensile loading. The majority of the samples were elastically anisotropic. Full waveform acoustic emission and tomographic data were collected while these samples were under load to give information concerning changes in the structure of the material as it was undergoing stress change and/or failure. Analysis of this data indicates that AE and tomographic techniques mutually compliment each other to give a view of the stress induced elastic changes in the tested samples.

  8. Association Between Pulmonary Uptake of Fluorodeoxyglucose Detected by Positron Emission Tomography Scanning After Radiation Therapy for Non-Small-Cell Lung Cancer and Radiation Pneumonitis

    SciTech Connect

    Mac Manus, Michael P.; Ding Zhe; Hogg, Annette; Herschtal, Alan; Binns, David; Ball, David L.; Hicks, Rodney J.

    2011-08-01

    Purpose: To study the relationship between fluorodeoxyglucose (FDG) uptake in pulmonary tissue after radical radiation therapy (RT) and the presence and severity of radiation pneumonitis. Methods and Materials: In 88 consecutive patients, {sup 18}F-FDG-positron emission tomography was performed at a median of 70 days after completion of RT. Patients received 60 Gy in 30 fractions, and all but 15 had concurrent platinum-based chemotherapy. RT-induced pulmonary inflammatory changes occurring within the radiation treatment volume were scored, using a visual (0 to 3) radiotoxicity grading scale, by an observer blinded to the presence or absence of clinical radiation pneumonitis. Radiation pneumonitis was retrospectively graded using the Radiation Therapy Oncology Group (RTOG) scale by an observer blinded to the PET radiotoxicity score. Results: There was a significant association between the worst RTOG pneumonitis grade occurring at any time after RT and the positron emission tomograph (PET) radiotoxicity grade (one-sided p = 0.033). The worst RTOG pneumonitis grade occurring after the PET scan was also associated with the PET radiotoxicity grade (one-sided p = 0.035). For every one-level increase in the PET toxicity scale, the risk of a higher RTOG radiation pneumonitis score increased by approximately 40%. The PET radiotoxicity score showed no significant correlation with the duration of radiation pneumonitis. Conclusions: The intensity of FDG uptake in pulmonary tissue after RT determined using a simple visual scoring system showed significant correlation with the presence and severity of radiation pneumonitis. {sup 18}F-FDG-PET may be useful in the prediction, diagnosis and therapeutic monitoring of radiation pneumonitis.

  9. Myocardial Blood Flow Quantification for Evaluation of Coronary Artery Disease by Positron Emission Tomography, Cardiac Magnetic Resonance Imaging, and Computed Tomography

    PubMed Central

    Waller, Alfonso H.; Blankstein, Ron; Kwong, Raymond Y.; Di Carli, Marcelo F.

    2014-01-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging and computed tomography, and its emerging clinical applications. PMID:24718671

  10. Positron Emission Tomography Imaging of Atherosclerosis

    PubMed Central

    Orbay, Hakan; Hong, Hao; Zhang, Yin; Cai, Weibo

    2013-01-01

    Atherosclerosis-related cardiovascular events are the leading causes of death in the industrialized world. Atherosclerosis develops insidiously and the initial manifestation is usually sudden cardiac death, stroke, or myocardial infarction. Molecular imaging is a valuable tool to identify the disease at an early stage before fatal manifestations occur. Among the various molecular imaging techniques, this review mainly focuses on positron emission tomography (PET) imaging of atherosclerosis. The targets and pathways that have been investigated to date for PET imaging of atherosclerosis include: glycolysis, cell membrane metabolism (phosphatidylcholine synthesis), integrin αvβ3, low density lipoprotein (LDL) receptors (LDLr), natriuretic peptide clearance receptors (NPCRs), fatty acid synthesis, vascular cell adhesion molecule-1 (VCAM-1), macrophages, platelets, etc. Many PET tracers have been investigated clinically for imaging of atherosclerosis. Early diagnosis of atherosclerotic lesions by PET imaging can help to prevent the premature death caused by atherosclerosis, and smooth translation of promising PET tracers into the clinic is critical to the benefit of patients. PMID:24312158

  11. Resistive plate chambers in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Crespo, Paulo; Blanco, Alberto; Couceiro, Miguel; Ferreira, Nuno C.; Lopes, Luís; Martins, Paulo; Ferreira Marques, Rui; Fonte, Paulo

    2013-07-01

    Resistive plate chambers (RPC) were originally deployed for high energy physics. Realizing how their properties match the needs of nuclear medicine, a LIP team proposed applying RPCs to both preclinical and clinical positron emission tomography (RPC-PET). We show a large-area RPC-PET simulated scanner covering an axial length of 2.4m —slightly superior to the height of the human body— allowing for whole-body, single-bed RPC-PET acquisitions. Simulations following NEMA (National Electrical Manufacturers Association, USA) protocols yield a system sensitivity at least one order of magnitude larger than present-day, commercial PET systems. Reconstruction of whole-body simulated data is feasible by using a dedicated, direct time-of-flight-based algorithm implemented onto an ordered subsets estimation maximization parallelized strategy. Whole-body RPC-PET patient images following the injection of only 2mCi of 18-fluorodesoxyglucose (FDG) are expected to be ready 7 minutes after the 6 minutes necessary for data acquisition. This compares to the 10-20mCi FDG presently injected for a PET scan, and to the uncomfortable 20-30minutes necessary for its data acquisition. In the preclinical field, two fully instrumented detector heads have been assembled aiming at a four-head-based, small-animal RPC-PET system. Images of a disk-shaped and a needle-like 22Na source show unprecedented sub-millimeter spatial resolution.

  12. A Review on Segmentation of Positron Emission Tomography Images

    PubMed Central

    Foster, Brent; Bagci, Ulas; Mansoor, Awais; Xu, Ziyue; Mollura, Daniel J.

    2014-01-01

    Positron Emission Tomography (PET), a non-invasive functional imaging method at the molecular level, images the distribution of biologically targeted radiotracers with high sensitivity. PET imaging provides detailed quantitative information about many diseases and is often used to evaluate inflammation, infection, and cancer by detecting emitted photons from a radiotracer localized to abnormal cells. In order to differentiate abnormal tissue from surrounding areas in PET images, image segmentation methods play a vital role; therefore, accurate image segmentation is often necessary for proper disease detection, diagnosis, treatment planning, and follow-ups. In this review paper, we present state-of-the-art PET image segmentation methods, as well as the recent advances in image segmentation techniques. In order to make this manuscript self-contained, we also briefly explain the fundamentals of PET imaging, the challenges of diagnostic PET image analysis, and the effects of these challenges on the segmentation results. PMID:24845019

  13. Resolution and Sensitivity in Positron Emission Tomography Imaging:. New Frontiers

    NASA Astrophysics Data System (ADS)

    Sossi, V.

    2004-07-01

    The combination of new detector technologies and rapidly increasing computing power is contributing to major developments in positron emission tomography (PET) imaging. The uniqueness of PET resides in its ability to detect very small concentrations of radioactively labeled tracers specifically designed to investigate selected biological functions. The desire to quantitatively observe increasingly complex biological processes together with the need of furthering research in small animal models of disease are pushing the limits of imaging spatial resolution and sensitivity. Resolution of approximately 10 mm3 is now achievable in human size brain scanners, while 1 mm3 can almost be reached in small animal imaging. Such ability will enable a more detailed exploration of healthy and disease function with the ultimate goal of imaging at a molecular level and of detecting pre-clinical disease induced changes.

  14. The Role of Chemistry in Positron Emission Tomography.

    ERIC Educational Resources Information Center

    Feliu, Anthony L.

    1988-01-01

    Investigates use of positron emission tomography (PET) to study in-vivo metabolic processes. Discusses methodology of PET and medical uses. Outlines the production of different radioisotopes used in PET radiotracers. Includes selected bibliography. (ML)

  15. Positron emission tomography detects greater blood flow and less blood flow heterogeneity in the exercising skeletal muscles of old compared with young men during fatiguing contractions.

    PubMed

    Rudroff, Thorsten; Weissman, Jessica A; Bucci, Marco; Seppänen, Marko; Kaskinoro, Kimmo; Heinonen, Ilkka; Kalliokoski, Kari K

    2014-01-15

    The purpose of this study was to investigate blood flow and its heterogeneity within and among the knee muscles in five young (26 ± 6 years) and five old (77 ± 6 years) healthy men with similar levels of physical activity while they performed two types of submaximal fatiguing isometric contraction that required either force or position control. Positron emission tomography (PET) and [(15)O]-H2O were used to determine blood flow at 2 min (beginning) and 12 min (end) after the start of the tasks. Young and old men had similar maximal forces and endurance times for the fatiguing tasks. Although muscle volumes were lower in the older subjects, total muscle blood flow was similar in both groups (young men: 25.8 ± 12.6 ml min(-1); old men: 25.1 ± 15.4 ml min(-1); age main effect, P = 0.77) as blood flow per unit mass of muscle in the exercising knee extensors was greater in the older (12.5 ± 6.2 ml min(-1) (100 g)(-1)) than the younger (8.6 ± 3.6 ml min(-1) (100 g)(-1)) men (age main effect, P = 0.001). Further, blood flow heterogeneity in the exercising knee extensors was significantly lower in the older (56 ± 27%) than the younger (67 ± 34%) men. Together, these data show that although skeletal muscles are smaller in older subjects, based on the intact neural drive to the muscle and the greater, less heterogeneous blood flow per gram of muscle, old fit muscle achieves adequate exercise hyperaemia.

  16. Detection of Local, Regional, and Distant Recurrence in Patients With PSA Relapse After External-Beam Radiotherapy Using {sup 11}C-Choline Positron Emission Tomography

    SciTech Connect

    Breeuwsma, Anthonius J.; Pruim, Jan; Bergh, Alphons C.M. van den; Leliveld, Anna M.; Nijman, Rien J.M.; Dierckx, Rudi A.J.O.; Jong, Igle J. de

    2010-05-01

    Purpose: An elevated serum prostate-specific antigen (PSA) level cannot distinguish between local-regional recurrences and the presence of distant metastases after treatment with curative intent for prostate cancer. With the advent of salvage treatment such as cryotherapy, it has become important to localize the site of recurrence (local or distant). In this study, the potential of {sup 11}C-choline positron emission tomography (PET) to identify site of recurrence was investigated in patients with rising PSA after external-beam radiotherapy (EBRT). Methods and Materials: Seventy patients with histologically proven prostate cancer treated with EBRT and showing biochemical recurrence as defined by American Society for Therapeutic Radiology and Oncology consensus statement and 10 patients without recurrence underwent a PET scan using 400 MBq {sup 11}C-choline intravenously. Biopsy-proven histology from the site of suspicion, findings with other imaging modalities, clinical follow-up and/or response to adjuvant therapy were used as comparative references. Results: None of the 10 patients without biochemical recurrence had a positive PET scan. Fifty-seven of 70 patients with biochemical recurrence (median PSA 9.1 ng/mL; mean PSA 12.3 ng/mL) showed an abnormal uptake pattern (sensitivity 81%). The site of recurrence was only local in 41 of 57 patients (mean PSA 11.1 ng/mL at scan), locoregionally and/or distant in 16 of 57 patients (mean PSA 17.7 ng/mL). Overall the positive predictive value and negative predictive value for {sup 11}C-choline PET scan were 1.0 and 0.44 respectively. Accuracy was 84%. Conclusions: {sup 11}C-choline PET scan is a sensitive technique to identify the site of recurrence in patients with PSA relapse after EBRT for prostate cancer.

  17. Radiofluorinated carbohydrates for positron emission tomography.

    PubMed

    Mun, Jiyoung

    2013-01-01

    2-Deoxy-2-[(18)F]fluoro-D-glucose (2-(18)FDG) has represented radiofluorinated carbohydrates as the most successful tracer for positron emission tomography (PET). 2-(18)FDG uptake depends on glucose metabolism, which is related to a disease progression. 2-(18)FDG has been widely used in oncology, neurology, cardiology, infectious diseases, and inflammation, to complement anatomical modalities such as CT and MRI. Followed by the success of 2-(18)FDG, various radiofluorinated carbohydrates have been evaluated as PET tracers, which include analogs of D-ribose, D-mannose, D-galactose, D-talose, D-fructose, D-allose, lactose, L-fucose, N-acetylneuraminic acid, and L-ascorbic acid. Among those radiofluorinated carbohydrates, several have implied potential for further development. 2-Deoxy-2-[(18)F]fluoro-D-galactose has been developed to assess liver function and diagnose hepatic carcinoma. 6-Deoxy-6-[(18)F]fluoro-D-fructose showed promising characteristics for diagnosis of breast cancer. Three radiofluorinated analogs of lactose have been designed as the substrates of the overexpressed hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein in peritumoral pancreatic tissue for early diagnosis of pancreatic cancer. The metabolism of 6-[(18)F]fluoro-L-fucose suggested that it is a bioactive analog of L-fucose in the synthesis of glycoconjugate macromolecules. 6-Deoxy-6-[(18)F]fluoro-L-ascorbic acid was evaluated to assess antioxidant function of L-ascorbic acid in rodent models of transient global ischemia and glutathione deficiency.

  18. Fuzzy-rule-based image reconstruction for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Mondal, Partha P.; Rajan, K.

    2005-09-01

    Positron emission tomography (PET) and single-photon emission computed tomography have revolutionized the field of medicine and biology. Penalized iterative algorithms based on maximum a posteriori (MAP) estimation eliminate noisy artifacts by utilizing available prior information in the reconstruction process but often result in a blurring effect. MAP-based algorithms fail to determine the density class in the reconstructed image and hence penalize the pixels irrespective of the density class. Reconstruction with better edge information is often difficult because prior knowledge is not taken into account. The recently introduced median-root-prior (MRP)-based algorithm preserves the edges, but a steplike streaking effect is observed in the reconstructed image, which is undesirable. A fuzzy approach is proposed for modeling the nature of interpixel interaction in order to build an artifact-free edge-preserving reconstruction. The proposed algorithm consists of two elementary steps: (1) edge detection, in which fuzzy-rule-based derivatives are used for the detection of edges in the nearest neighborhood window (which is equivalent to recognizing nearby density classes), and (2) fuzzy smoothing, in which penalization is performed only for those pixels for which no edge is detected in the nearest neighborhood. Both of these operations are carried out iteratively until the image converges. Analysis shows that the proposed fuzzy-rule-based reconstruction algorithm is capable of producing qualitatively better reconstructed images than those reconstructed by MAP and MRP algorithms. The reconstructed images are sharper, with small features being better resolved owing to the nature of the fuzzy potential function.

  19. Positron Emission Tomography: state of the art and future developments

    NASA Astrophysics Data System (ADS)

    Pizzichemi, M.

    2016-08-01

    Positron emission tomography (PET) plays a fundamental role in medical imaging, with a wide range of applications covering, among the others, oncology, neurology and cardiology. PET has undergone a steady technological evolution since its introduction in mid 20th century, from the development of 3D PET in the late 1980s, to the invention of PET/CT in the 1990s and more recently with the introduction of PET/MR scanners. The current research topics aiming to develop the next generation of PET scanners are summarized in this paper, focusing on the efforts to increase the sensitivity of the detectors, as long as improving their timing, spatial and energy resolutions, with the final goal of reducing the amount of radioactive dose received by the patients and the duration of the exams while improving at the same time the detectability of lesions.

  20. Characterization of nontransmural myocardial infarction by positron-emission tomography

    SciTech Connect

    Geltman, E.M.; Biello, D.; Welch, M.J.; Ter-Pogossian, M.M.; Roberts, R.; Sobel, B.E.

    1982-04-01

    The present study was performed to determine whether positron emission tomography (PET) performed after i.v. 11C-palmitate permits detection and characterization of nontransmural myocardial infarction. PET was performed after the i.v. injection of 11C-palmitate in 10 normal subjects, 24 patients with initial nontransmural myocardial infarction (defined electrocardiographically), and 22 patients with transmural infarction. Depressed accumulation of 11C-palmitate was detected with sagittal, coronal and transverse reconstructions, and quantified based on 14 contiguous transaxial reconstructions. Defects with homogeneously intense depression of accumulation of tracer were detected in all 22 patients with transmural infarction (100%). Abnormalities of the distribution of 11C-palmitate in the myocardium were detected in 23 patients with nontransmural infarction (96%). Thallium scintigrams were abnormal in only 11 of 18 patients with nontransmural infarction (61%). Tomographically estimated infarct size was greater among patients with transmural infarction (50.4 +/- 7.8 PET-g-Eq/m2 (+/- SEM SEM)) compared with those with nontransmural infarction (19 +/- 4 PET-g-Eq, p less than 0.01). Residual accumulation of 11C-palmitate within regions of infarction was more intensely depressed among patients with transmural compared to nontransmural infarction (33 +/- 1 vs 39 +/- 1% maximal myocardial radioactivity, p less than 0.01). Thus, PET and metabolic imaging with 11C-palmitate is a sensitive means of detecting, quantifying and characterizing nontransmural and transmural myocardial infarction.

  1. An online emission spectral tomography system with digital signal processor.

    PubMed

    Wan, Xiong; Xiong, Wenlin; Zhang, Zhimin; Chang, Fangfei

    2009-03-30

    Emission spectral tomography (EST) has been adopted to test the three-dimensional distribution parameters of fluid fields, such as burning gas, flame and plasma etc. In most cases, emission spectral data received by the video cameras are enormous so that the emission spectral tomography calculation is often time-consuming. Hence, accelerating calculation becomes the chief factor that one must consider for the practical application of EST. To solve the problem, a hardware implementation method was proposed in this paper, which adopted a digital signal processor (DSP) DM642 in an emission spectral tomography test system. The EST algorithm was fulfilled in the DSP, then calculation results were transmitted to the main computer via the user datagram protocol. Compared with purely VC++ software implementations, this new approach can decrease the calculation time significantly.

  2. [Positron emission tomography (PET) in malignant ovarian tumors].

    PubMed

    Fularz, Maciej; Adamiak, Paulina; Czepczyński, Rafał; Jarzabek-Bielecka, Grazyna; Kedzia, Witold; Ruchała, Marek

    2013-08-01

    Accessibility of positron emission tomography integrated with computed tomography (PET/CT) has improved significantly in recent years. PET/CT with the use of 18F-deoxyglucose (FDG) is widely used in patients with ovarian malignancies at different stages of the management. FDG PET/CT shows high diagnostic accuracy in the differentiation of benign and malignant ovarian lesions with the exception of borderline tumors that may cause false negative results. Moreover FDG PET/CT is used in some centers for preoperative staging and determining the prognosis of ovarian cancer However further studies including larger groups of patients are needed to confirm the applicability of FDG PET/CT in case of the two abovementioned indications. Until now, the best documented indication for FDG PET/ CT in patients with ovarian cancer has been the detection of recurrence, especially in subjects with elevated CA 125 marker and negative results of other imaging techniques. This review focuses on the applicability of PET with the use of FDG in ovarian malignancies and points out to the limitations of this method.

  3. New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

    PubMed Central

    Yoon, Hyuk; Lee, Dong Ho

    2014-01-01

    Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and 18F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years. PMID:25320516

  4. Ultrasonic guided wave tomography for ice detection.

    PubMed

    Zhao, Xiang; Rose, Joseph L

    2016-04-01

    Of great concern for many structures, particularly critical sections of rotary and fixed wing aircrafts, is the ability to detect ice either on grounded or in-flight vehicles. As a consequence, some work is reported here that could be useful for a variety of different industries where ice formation is an important problem. This paper presents experimental validations of a probability-based reconstruction algorithm (PRA) on ice detection of plate-like structures. The ice detection tests are performed for three different specimens: a single layer aluminum plate with a circular ice sensing array, a titanium plate with a sparse rectangular ice sensing array, and a carbon-fiber-reinforced titanium plate with an embedded ice sensing array mounted on a carbon fiber back plate. Cases from the simple to the more challenging exemplify that special modes can be used to differentiate ice from water, a sparse rectangular array could also be used for ice detection, and an ice sensing array could be further used to detect the ice on the sensor free side, a very useful application of ice sensing for aircraft wings, for example. Ice detection images for the respective cases are reconstructed to investigate the feasibility of ice sensing with ultrasonic guided wave tomography technology. The results show that the PRA based ultrasonic guided wave tomography method successfully detected and showed ice spots correctly for all three cases. This corroborates the fact that ultrasonic guided wave imaging technology could be a potential useful ice sensing tool in plate-like structures. PMID:26746159

  5. 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.

  6. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis. PMID:25589818

  7. Gliomatosis cerebri mimicking encephalitis evaluated using fluorine-18 fluorodeoxyglucose: Positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Krishnan, Vijayan; Mohanan, Vyshakh; Shibu, Deepu; Shinto, Ajit Sugunan

    2015-01-01

    Gliomatosis cerebri (GC) is a rare condition in which an infiltrative glial neoplasm spreads through the brain with preservation of the underlying structure. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has an important role in demonstrating the appropriate metabolism and differentiating pathologies mimicking GC on CT and magnetic resonance imaging. We describe imaging findings of FDG PET/CT in GC in a 9-year-old male child mimicking encephalitis.

  8. Pigmented villonodular synovitis mimics metastases on fluorine 18 fluorodeoxyglucose position emission tomography-computed tomography

    PubMed Central

    Elumogo, Comfort O.; Kochenderfer, James N.; Civelek, A. Cahid

    2016-01-01

    Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose (18F-FDG) position emission tomography-computed tomography (PET-CT) in the diagnosis or characterization remains unclear. PVNS displays as a focal FDG avid lesion, which can masquerade as a metastatic lesion, on PET-CET. We present a case of PVNS found on surveillance imaging of a lymphoma patient. PMID:27190776

  9. 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

  10. Single Photon Emission Local Tomography (SPELT)

    SciTech Connect

    Zeng, G.L.; Gullberg, G.T.

    1996-12-31

    Local tomography uses truncated projection data to reconstruct a region of interest, and is important in medical imaging and industrial non-destructive evaluation using micro X-ray CT. The popular filtered backprojection (FBP) algorithm does not reconstruct a reliable image, which varies with the degree and location of truncation due to its global convolution kernel. A typical local tomography method uses a second derivative local operator to replace the global convolution kernel in the filtered backprojection algorithm (LFBP). By using a local filter, the reconstructed region depends only on the local projections. The singularities (edges) are preserved, but the exact image value cannot be recovered. This paper, using the data consistency conditions, developed a pre-processing technique that uses the FBP algorithm, which outperforms direct FBP and LFBP.

  11. The Positron Emission Tomography Tracer 3’-Deoxy-3’-[18F]Fluorothymidine ([18F]FLT) Is Not Suitable to Detect Tissue Proliferation Induced by Systemic Yersinia enterocolitica Infection in Mice

    PubMed Central

    Rolle, Anna-Maria; Warnke, Philipp; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Reischl, Gerald; Autenrieth, Ingo B.; Pichler, Bernd J.; Autenrieth, Stella E.

    2016-01-01

    Most frequently, gram-negative bacterial infections in humans are caused by Enterobacteriaceae and remain a major challenge in medical diagnostics. We non-invasively imaged moderate and severe systemic Yersinia enterocolitica infections in mice using the positron emission tomography (PET) tracer 3’-deoxy-3’-[18F]fluorothymidine ([18F]FLT), which is a marker of proliferation, and compared the in vivo results to the ex vivo biodistributions, bacterial loads, and histologies of the corresponding organs. Y. enterocolitica infection is detectable with histology using H&E staining and immunohistochemistry for Ki 67. [18F]FLT revealed only background uptake in the spleen, which is the main manifestation site of systemic Y. enterocolitica-infected mice. The uptake was independent of the infection dose. Antibody-based thymidine kinase 1 (Tk-1) staining confirmed the negative [18F]FLT-PET data. Histological alterations of spleen tissue, observed via Ki 67-antibody-based staining, can not be detected by [18F]FLT-PET in this model. Thus, the proliferation marker [18F]FLT is not a suitable tracer for the diagnosis of systemic Y. enterocolitica infection in the C57BL/6 animal model of yersiniosis. PMID:27701464

  12. Addiction Studies with Positron Emission Tomography

    SciTech Connect

    Joanna Fowler

    2008-10-13

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  13. Addiction Studies with Positron Emission Tomography

    ScienceCinema

    Joanna Fowler

    2016-07-12

    Brookhaven scientist Joanna Fowler describes Positron Emission Technology (PET) research at BNL which for the past 30 years has focused in the integration of basic research in radiotracer chemistry with the tools of neuroscience to develop new scientific

  14. Positron Emission Tomography: Human Brain Function and Biochemistry.

    ERIC Educational Resources Information Center

    Phelps, Michael E.; Mazziotta, John C.

    1985-01-01

    Describes the method, present status, and application of positron emission tomography (PET), an analytical imaging technique for "in vivo" measurements of the anatomical distribution and rates of specific biochemical reactions. Measurements and image dynamic biochemistry link basic and clinical neurosciences with clinical findings suggesting…

  15. Positron Emission Tomography: Current Challenges and Opportunities for Technological Advances in Clinical and Preclinical Imaging Systems.

    PubMed

    Vaquero, Juan José; Kinahan, Paul

    2015-01-01

    Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges.

  16. Positron Emission Tomography: Current Challenges and Opportunities for Technological Advances in Clinical and Preclinical Imaging Systems.

    PubMed

    Vaquero, Juan José; Kinahan, Paul

    2015-01-01

    Positron emission tomography (PET) imaging is based on detecting two time-coincident high-energy photons from the emission of a positron-emitting radioisotope. The physics of the emission, and the detection of the coincident photons, give PET imaging unique capabilities for both very high sensitivity and accurate estimation of the in vivo concentration of the radiotracer. PET imaging has been widely adopted as an important clinical modality for oncological, cardiovascular, and neurological applications. PET imaging has also become an important tool in preclinical studies, particularly for investigating murine models of disease and other small-animal models. However, there are several challenges to using PET imaging systems. These include the fundamental trade-offs between resolution and noise, the quantitative accuracy of the measurements, and integration with X-ray computed tomography and magnetic resonance imaging. In this article, we review how researchers and industry are addressing these challenges. PMID:26643024

  17. Prostate cancer nodal oligometastasis accurately assessed using prostate-specific membrane antigen positron emission tomography-computed tomography and confirmed histologically following robotic-assisted lymph node dissection

    PubMed Central

    O’Kane, Dermot B.; Lawrentschuk, Nathan; Bolton, Damien M.

    2016-01-01

    We herein present a case of a 76-year-old gentleman, where prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) was used to accurately detect prostate cancer (PCa), pelvic lymph node (LN) metastasis in the setting of biochemical recurrence following definitive treatment for PCa. The positive PSMA PET-CT result was confirmed with histological examination of the involved pelvic LNs following pelvic LN dissection. PMID:27141207

  18. Multiphoton tomography to detect chemo- and biohazards

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2015-03-01

    In vivo high-resolution multiphoton/CARS tomography provides optical biopsies with 300 nm lateral resolution with chemical fingerprints. Thousands of volunteers and patients have been investigated for early cancer diagnosis, evaluation of anti-ageing cosmetic products, and changes of cellular metabolism by UV exposure and decreased oxygen supply. The skin as the outermost and largest organ is also the major target of CB agents. Current UV-based sensors are useful for bio-aerosol sensing but not for evaluating exposed in vivo skin. Here we evaluate the use of 4D multiphoton/CARS tomographs based on near infrared femtosecond laser radiation, time-correlated single photon counting (FLIM) and white light generation by photonic crystal fibers to detect bio- and chemohazards in human in vivo skin using twophoton fluorescence, SHG, and Raman signals.

  19. Shape threat detection via adaptive computed tomography

    NASA Astrophysics Data System (ADS)

    Masoudi, Ahmad; Thamvichai, Ratchaneekorn; Neifeld, Mark A.

    2016-05-01

    X-ray Computed Tomography (CT) is used widely for screening purposes. Conventional x-ray threat detection systems employ image reconstruction and segmentation algorithms prior to making threat/no-threat decisions. We find that in many cases these pre-processing steps can degrade detection performance. Therefore in this work we will investigate methods that operate directly on the CT measurements. We analyze a fixed-gantry system containing 25 x-ray sources and 2200 photon counting detectors. We present a new method for improving threat detection performance. This new method is a so-called greedy adaptive algorithm which at each time step uses information from previous measurements to design the next measurement. We utilize sequential hypothesis testing (SHT) in order to derive both the optimal "next measurement" and the stopping criterion to insure a target probability of error Pe. We find that selecting the next x-ray source according to such a greedy adaptive algorithm, we can reduce Pe by a factor of 42.4× relative to the conventional measurement sequence employing all 25 sources in sequence.

  20. Silicon as an unconventional detector in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Clinthorne, Neal; Brzezinski, Karol; Chesi, Enrico; Cochran, Eric; Grkovski, Milan; Grošičar, Borut; Honscheid, Klaus; Huh, Sam; Kagan, Harris; Lacasta, Carlos; Linhart, Vladimir; Mikuž, Marko; Smith, D. Shane; Stankova, Vera; Studen, Andrej; Weilhammer, Peter; Žontar, Dejan

    2013-01-01

    Positron emission tomography (PET) is a widely used technique in medical imaging and in studying small animal models of human disease. In the conventional approach, the 511 keV annihilation photons emitted from a patient or small animal are detected by a ring of scintillators such as LYSO read out by arrays of photodetectors. Although this has been successful in achieving ˜5 mm FWHM spatial resolution in human studies and ˜1 mm resolution in dedicated small animal instruments, there is interest in significantly improving these figures. Silicon, although its stopping power is modest for 511 keV photons, offers a number of potential advantages over more conventional approaches including the potential for high intrinsic spatial resolution in 3D. To evaluate silicon in a variety of PET "magnifying glass" configurations, an instrument was constructed that consists of an outer partial-ring of PET scintillation detectors into which various arrangements of silicon detectors are inserted to emulate dual-ring or imaging probe geometries. Measurements using the test instrument demonstrated the capability of clearly resolving point sources of 22Na having a 1.5 mm center-to-center spacing as well as the 1.2 mm rods of a 18F-filled resolution phantom. Although many challenges remain, silicon has potential to become the PET detector of choice when spatial resolution is the primary consideration.

  1. Imaging pancreatic islet cells by positron emission tomography

    PubMed Central

    Li, Junfeng; Karunananthan, Johann; Pelham, Bradley; Kandeel, Fouad

    2016-01-01

    It was estimated that every year more than 30000 persons in the United States - approximately 80 people per day - are diagnosed with type 1 diabetes (T1D). T1D is caused by autoimmune destruction of the pancreatic islet (β cells) cells. Islet transplantation has become a promising therapy option for T1D patients, while the lack of suitable tools is difficult to directly evaluate of the viability of the grafted islet over time. Positron emission tomography (PET) as an important non-invasive methodology providing high sensitivity and good resolution, is able to accurate detection of the disturbed biochemical processes and physiological abnormality in living organism. The successful PET imaging of islets would be able to localize the specific site where transplanted islets engraft in the liver, and to quantify the level of islets remain alive and functional over time. This information would be vital to establishing and evaluating the efficiency of pancreatic islet transplantation. Many novel imaging agents have been developed to improve the sensitivity and specificity of PET islet imaging. In this article, we summarize the latest developments in carbon-11, fluorine-18, copper-64, and gallium-68 labeled radioligands for the PET imaging of pancreatic islet cells. PMID:27721939

  2. High-resolution 18F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging for pituitary adenoma detection in Cushing disease

    PubMed Central

    Chittiboina, Prashant; Montgomery, Blake K.; Millo, Corina; Herscovitch, Peter; Lonser, Russell R.

    2016-01-01

    OBJECT High-resolution PET (hrPET) performed using a high-resolution research tomograph is reported as having a resolution of 2 mm and could be used to detect corticotroph adenomas through uptake of 18F-fluorodeoxyglucose (18F-FDG). To determine the sensitivity of this imaging modality, the authors compared 18F-FDG hrPET and MRI detection of pituitary adenomas in Cushing disease (CD). METHODS Consecutive patients with CD who underwent preoperative 18F-FDG hrPET and MRI (spin echo [SE] and spoiled gradient recalled [SPGR] sequences) were prospectively analyzed. Standardized uptake values (SUVs) were calculated from hrPET and were compared with MRI findings. Imaging findings were correlated to operative and histological findings. RESULTS Ten patients (7 females and 3 males) were included (mean age 30.8 ± 19.3 years; range 11–59 years). MRI revealed a pituitary adenoma in 4 patients (40% of patients) on SE and 7 patients (70%) on SPGR sequences. 18F-FDG hrPET demonstrated increased 18F-FDG uptake consistent with an adenoma in 4 patients (40%; adenoma size range 3–14 mm). Maximum SUV was significantly higher for 18F-FDG hrPET–positive tumors (difference = 5.1, 95% CI 2.1–8.1; p = 0.004) than for 18F-FDG hrPET–negative tumors. 18F-FDG hrPET positivity was not associated with tumor volume (p = 0.2) or dural invasion (p = 0.5). Midnight and morning ACTH levels were associated with 18F-FDG hrPET positivity (p = 0.01 and 0.04, respectively) and correlated with the maximum SUV (R = 0.9; p = 0.001) and average SUV (R = 0.8; p = 0.01). All 18F-FDG hrPET–positive adenomas had a less than a 180% ACTH increase and 18F-FDG hrPET–negative adenomas had a greater than 180% ACTH increase after CRH stimulation (p = 0.03). Three adenomas were detected on SPGR MRI sequences that were not detected by 18F-FDG hrPET imaging. Two adenomas not detected on SE (but no adenomas not detected on SPGR) were detected on 18F-FDG hrPET. CONCLUSIONS While 18F-FDG hrPET imaging can detect

  3. Detection of isolated ipsilateral regional lymph node recurrences by F18-fluorodeoxyglucose positron emission tomography-CT in follow-up of postoperative breast cancer patients.

    PubMed

    Ohsumi, Shozo; Inoue, Takeshi; Kiyoto, Sachiko; Hara, Fumikata; Takahashi, Mina; Takabatake, Daisuke; Takashima, Seiki; Aogi, Kenjiro; Takashima, Shigemitsu

    2011-11-01

    Imaging diagnostic methods except for mammograms are not recommended for follow-up of postoperative breast cancer patients in order to detect small recurrences because of the poor survival improvement in earlier randomized trials. However, the use of new imaging modalities may improve survival by detection of small isolated regional lymph node recurrences which are potentially curable. Between April 2006 and December 2008, we used PET-CT to find small recurrences in follow-up of 1,907 postoperative breast cancer patients. A total of 3,280 PET-CT imagings were performed. The median age at PET-CT imaging was 58 years, with a median 48-month interval from definitive surgery to the PET-CT imaging. Twenty-two patients were found to have isolated ipsilateral regional recurrences only by PET-CT (axillary node recurrences in 6, infraclavicular node recurrences in 5, supraclavicular node recurrences in 6, and parasternal node recurrences in 5). All of those recurrences were missed by palpation or were nonpalpable. The pathological lymph node status at the definitive surgery for the primary breast cancer of 22 patients with the isolated ipsilateral regional lymph node recurrences was positive in 17 patients. If patients are limited to those who had pathologically positive node(s) at definitive surgery, the incidence of patients with isolated regional lymph node recurrences found only by PET-CT would be 2.6% (17/663 patients). Seventeen other asymptomatic cancers including contralateral breast cancers were found only by PET-CT. Early detection of isolated loco-regional recurrences of breast cancer is suggested to result in improved survival. Therefore, the use of PET-CT in follow-up of postoperative node-positive breast cancer patients may improve their survival because of early detection of isolated regional lymph node recurrences which are still potentially curable, and screening of other asymptomatic cancers. PMID:21590272

  4. Role of Positron Emission Tomography-Computed Tomography in the Management of Anal Cancer

    SciTech Connect

    Mistrangelo, Massimiliano; Pelosi, Ettore; Bello, Marilena; Ricardi, Umberto; Milanesi, Enrica; Cassoni, Paola; Baccega, Massimo; Filippini, Claudia; Racca, Patrizia; Lesca, Adriana; Munoz, Fernando H.; Fora, Gianluca; Skanjeti, Andrea; Cravero, Francesca; Morino, Mario

    2012-09-01

    Purpose: Pre- and post-treatment staging of anal cancer are often inaccurate. The role of positron emission tomograpy-computed tomography (PET-CT) in anal cancer is yet to be defined. The aim of the study was to compare PET-CT with CT scan, sentinel node biopsy results of inguinal lymph nodes, and anal biopsy results in staging and in follow-up of anal cancer. Methods and Materials: Fifty-three consecutive patients diagnosed with anal cancer underwent PET-CT. Results were compared with computed tomography (CT), performed in 40 patients, and with sentinel node biopsy (SNB) (41 patients) at pretreatment workup. Early follow-up consisted of a digital rectal examination, an anoscopy, a PET-CT scan, and anal biopsies performed at 1 and 3 months after the end of treatment. Data sets were then compared. Results: At pretreatment assessment, anal cancer was identified by PET-CT in 47 patients (88.7%) and by CT in 30 patients (75%). The detection rates rose to 97.9% with PET-CT and to 82.9% with CT (P=.042) when the 5 patients who had undergone surgery prior to this assessment and whose margins were positive at histological examination were censored. Perirectal and/or pelvic nodes were considered metastatic by PET-CT in 14 of 53 patients (26.4%) and by CT in 7 of 40 patients (17.5%). SNB was superior to both PET-CT and CT in detecting inguinal lymph nodes. PET-CT upstaged 37.5% of patients and downstaged 25% of patients. Radiation fields were changed in 12.6% of patients. PET-CT at 3 months was more accurate than PET-CT at 1 month in evaluating outcomes after chemoradiation therapy treatment: sensitivity was 100% vs 66.6%, and specificity was 97.4% vs 92.5%, respectively. Median follow-up was 20.3 months. Conclusions: In this series, PET-CT detected the primary tumor more often than CT. Staging of perirectal/pelvic or inguinal lymph nodes was better with PET-CT. SNB was more accurate in staging inguinal lymph nodes.

  5. [Positron emission tomography/computed tomography in follow-up programmes for patients with colorectal cancer].

    PubMed

    Hansen, Anne Fogh; Jensen, Mads Radmer; Nordholm-Carstensen, Andreas

    2016-09-12

    The current follow-up programmes for patients with colorectal cancer (CRC) after curative surgery do not include 18F-fluorodeoxyglucose-positron emission tomography (PET). Several small studies on selected patient populations indicate a high sensitivity of PET/computed tomography (CT) on visualizing relapse in patients with CRC after curative surgery. Therefore, PET/CT could probably be valuable in patients with unexplained increase in carcinoembryonic antigen level or a clinical suspicion of relapse, but PET/CT is not recommended as a standard in follow-up after CRC. PMID:27649583

  6. Polarization sensitive optical coherence tomography detection method

    SciTech Connect

    Everett, M J; Sathyam, U S; Colston, B W; DaSilva, L B; Fried, D; Ragadio, J N; Featherstone, J D B

    1999-05-12

    This study demonstrates the potential of polarization sensitive optical coherence tomography (PS-OCT) for non-invasive in vivo detection and characterization of early, incipient caries lesions. PS-OCT generates cross-sectional images of biological tissue while measuring the effect of the tissue on the polarization state of incident light. Clear discrimination between regions of normal and demineralized enamel is first shown in PS-OCT images of bovine enamel blocks containing well-characterized artificial lesions. High-resolution, cross-sectional images of extracted human teeth are then generated that clearly discriminate between the normal and carious regions on both the smooth and occlusal surfaces. Regions of the teeth that appeared to be demineralized in the PS-OCT images were verified using histological thin sections examined under polarized light microscopy. The PS-OCT system discriminates between normal and carious regions by measuring the polarization state of the back-scattered 1310 nm light, which is affected by the state of demineralization of the enamel. Demineralization of enamel increases the scattereing coefficient, thus depolarizing the incident light. This study shows that PS-OCT has great potential for the detection, characterization, and monitoring of incipient caries lesions.

  7. Utility of 18F-choline photon emission tomography/computed tomography in the diagnosis of parathyroid adenoma

    PubMed Central

    Damle, Nishikant Avinash; Tripathi, Madhavi; Behera, Abhishek; Aggarwal, Sameer; Bal, Chandrasekhar; Aggarwal, Shipra; Aggarwal, Vivek; Kandasamy, Devasenathipathi; Taywade, Sameer

    2016-01-01

    Recently, the role of 18F-choline in the detection of parathyroid adenomas has been reported. At our institution, we are currently studying the role of this tracer in comparison to the standard methoxy-isobutyl-isonitrile.(MIBI) scan with single photon emission tomography/computed tomography. Our initial results show that 18F-choline is at least as good as 99mTc-MIBI scan. We present here a representative case of a 45-year-old woman with multiple skeletal lytic lesions and a high parathyroid hormone.(PTH) who underwent both these imaging techniques with concordant results, further confirmed by histopathology and postoperative fall in serum PTH levels. PMID:27385893

  8. Positron Emission Tomography (PET) in Oncology

    PubMed Central

    Gallamini, Andrea; Zwarthoed, Colette; Borra, Anna

    2014-01-01

    Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%–15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later. PMID:25268160

  9. High uptake in schneiderian papillomas of the maxillary sinus on positron-emission tomography using fluorodeoxyglucose.

    PubMed

    Lin, F Y; Genden, E M; Lawson, W L; Som, P; Kostakoglu, L

    2009-02-01

    Schneiderian papillomas are benign tumors of the nasal cavity and paranasal sinuses often asymptomatic in their early stages. We report a case of a maxillary sinus oncocytic schneiderian papilloma first detected by positron-emission tomography by using fluorodeoxyglucose (FDG). Schneiderian papillomas demonstrate increased FDG uptake, similar to that of other oncocytic tumors, making it important for otolaryngologists and radiologists to realize that high uptake of FDG does not necessarily indicate a malignant lesion. PMID:18768722

  10. Positron Emission Tomography in Breast Cancer

    PubMed Central

    Vercher-Conejero, Jose Luis; Pelegrí-Martinez, Laura; Lopez-Aznar, Diego; Cózar-Santiago, María del Puig

    2015-01-01

    Gradually, FDG-PET/CT has been strengthening within the diagnostic algorithms of oncological diseases. In many of these, PET/CT has shown to be useful at different stages of the disease: diagnosis, staging or re-staging, treatment response assessment, and recurrence. Some of the advantages of this imaging modality versus CT, MRI, bone scan, mammography, or ultrasound, are based on its great diagnostic capacity since, according to the radiopharmaceutical used, it reflects metabolic changes that often occur before morphological changes and therefore allows us to stage at diagnosis. Moreover, another advantage of this technique is that it allows us to evaluate the whole body so it can be very useful for the detection of distant disease. With regard to breast cancer, FDG-PET/CT has proven to be important when recurrence is suspected or in the evaluation of treatment response. The technological advancement of PET equipment through the development of new detectors and equipment designed specifically for breast imaging, and the development of more specific radiopharmaceuticals for the study of the different biological processes of breast cancer, will allow progress not only in making the diagnosis of the disease at an early stage but also in enabling personalized therapy for patients with breast cancer. PMID:26854143

  11. Occipital lobe infarction and positron emission tomography.

    PubMed

    Tagawa, K; Nagata, K; Shishido, F

    1990-08-01

    Even though the PET study revealed a total infarct in the territory of the left PCA in our 3 cases of pure alexia, it is still obscure which part of the left occipital lobe is most closely associated with the occurrence of the pure alexia. In order to elucidate the intralobar localization of the pure alexia, it is needed to have an ideal case who shows an pure alexia due to the localized lesion within the left occipital lobe. Furthermore, high-resolution PET scanner will circumvent the problem in detecting the metabolism and blood flow in the corpus callosum which plays an important role in the pathogenesis. We have shown that the occlusion of the right PCA also produced a left unilateral agnosia which is one of the common neurological signs in the right MCA infarction. To tell whether the responsible lesion for the unilateral spatial agnosia differs between the PCA occlusion and the MCA occlusion, the correlation study should be carried out in a greater number of the subjects. Two distinctive neuropsychological manifestations, cerebral color blindness and prosopagnosia, have been considered to be produced by the bilateral occipital lesion. The PET studies disclosed reduction of blood flow and oxygen metabolism in both occipital lobes in our particular patient who exhibited cerebral color blindness and prosopagnosia.

  12. Simultaneous iterative reconstruction of emission and attenuation images in positron emission tomography from emission data only.

    PubMed

    Landmann, M; Reske, S N; Glatting, G

    2002-09-01

    For quantitative image reconstruction in positron emission tomography attenuation correction is mandatory. In case that no data are available for the calculation of the attenuation correction factors one can try to determine them from the emission data alone. However, it is not clear if the information content is sufficient to yield an adequate attenuation correction together with a satisfactory activity distribution. Therefore, we determined the log likelihood distribution for a thorax phantom depending on the choice of attenuation and activity pixel values to measure the crosstalk between both. In addition an iterative image reconstruction (one-dimensional Newton-type algorithm with a maximum likelihood estimator), which simultaneously reconstructs the images of the activity distribution and the attenuation coefficients is used to demonstrate the problems and possibilities of such a reconstruction. As result we show that for a change of the log likelihood in the range of statistical noise, the associated change in the activity value of a structure is between 6% and 263%. In addition, we show that it is not possible to choose the best maximum on the basis of the log likelihood when a regularization is used, because the coupling between different structures mediated by the (smoothing) regularization prevents an adequate solution due to crosstalk. We conclude that taking into account the attenuation information in the emission data improves the performance of image reconstruction with respect to the bias of the activities, however, the reconstruction still is not quantitative.

  13. Positron emission tomography radiopharmaceuticals for imaging brain Beta-amyloid.

    PubMed

    Vallabhajosula, Shankar

    2011-07-01

    Alzheimer's disease (AD) is defined histologically by the presence of extracellular β-amyloid (Aβ) plaques and intraneuronal neurofibrillary tangles in the cerebral cortex. The diagnosis of dementia, along with the prediction of who will develop dementia, has been assisted by magnetic resonance imaging and positron emission tomography (PET) by using [(18)F]fluorodeoxyglucose (FDG). These techniques, however, are not specific for AD. Based on the chemistry of histologic staining dyes, several Aβ-specific positron-emitting radiotracers have been developed to image neuropathology of AD. Among these, [(11)C]PiB is the most studied Aβ-binding PET radiopharmaceutical in the world. The histologic and biochemical specificity of PiB binding across different regions of the AD brain was demonstrated by showing a direct correlation between Aβ-containing amyloid plaques and in vivo [(11)C]PiB retention measured by PET imaging. Because (11)C is not ideal for commercialization, several (18)F-labeled tracers have been developed. At this time, [(18)F]3'-F-PiB (Flutemetamol), (18)F-AV-45 (Florbetapir), and (18)F-AV-1 (Florbetaben) are undergoing extensive phase II and III clinical trials. This article provides a brief review of the amyloid biology and chemistry of Aβ-specific (11)C and (18)F-PET radiopharmaceuticals. Clinical trials have clearly documented that PET radiopharmaceuticals capable of assessing Aβ content in vivo in the brains of AD subjects and subjects with mild cognitive impairment will be important as diagnostic agents to detect in vivo amyloid brain pathology. In addition, PET amyloid imaging will also help test the amyloid cascade hypothesis of AD and as an aid to assess the efficacy of antiamyloid therapeutics currently under development in clinical trials.

  14. Noninvasive imaging of islet grafts using positron-emission tomography

    NASA Astrophysics Data System (ADS)

    Lu, Yuxin; Dang, Hoa; Middleton, Blake; Zhang, Zesong; Washburn, Lorraine; Stout, David B.; Campbell-Thompson, Martha; Atkinson, Mark A.; Phelps, Michael; Gambhir, Sanjiv Sam; Tian, Jide; Kaufman, Daniel L.

    2006-07-01

    Islet transplantation offers a potential therapy to restore glucose homeostasis in type 1 diabetes patients. However, islet transplantation is not routinely successful because most islet recipients gradually lose graft function. Furthermore, serological markers of islet function are insensitive to islet loss until the latter stages of islet graft rejection. A noninvasive method of monitoring islet grafts would aid in the assessment of islet graft survival and the evaluation of interventions designed to prolong graft survival. Here, we show that recombinant adenovirus can engineer isolated islets to express a positron-emission tomography (PET) reporter gene and that these islets can be repeatedly imaged by using microPET after transplantation into mice. The magnitude of signal from engineered islets implanted into the axillary cavity was directly related to the implanted islet mass. PET signals attenuated over the following weeks because of the transient nature of adenovirus-mediated gene expression. Because the liver is the preferred site for islet implantation in humans, we also tested whether islets could be imaged after transfusion into the mouse liver. Control studies revealed that both intrahepatic islet transplantation and hyperglycemia altered the biodistribution kinetics of the PET probe systemically. Although transplanted islets were dispersed throughout the liver, clear signals from the liver region of mice receiving PET reporter-expressing islets were detectable for several weeks. Viral transduction, PET reporter expression, and repeated microPET imaging had no apparent deleterious effects on islet function after implantation. These studies lay a foundation for noninvasive quantitative assessments of islet graft survival using PET. diabetes | transplantation

  15. 18F-FDG positron emission tomography in oncology: main indications.

    PubMed

    Vercher-Conejero, J L; Gámez Cenzano, C

    2016-01-01

    The development of molecular and functional imaging with new imaging techniques such as computed tomography, magnetic resonance imaging, and positron emission tomography (PET) among others, has greatly improved the detection of tumors, tumor staging, and the detection of possible recurrences. Furthermore, the combination of these different imaging modalities and the continual development of radiotracers for PET have advanced our understanding and knowledge of the different pathophysiological processes in cancer, thereby helping to make treatment more efficacious, improving patients' quality of life, and increasing survival. PET is one of the imaging techniques that has attracted the most interest in recent years for its diagnostic capabilities. Its ability to anatomically locate pathologic foci of metabolic activity has revolutionized the detection and staging of many tumors, exponentially broadening its potential indications not only in oncology but also in other fields such as cardiology, neurology, and inflammatory and infectious diseases. PMID:27184919

  16. 18F-FDG positron emission tomography in oncology: main indications.

    PubMed

    Vercher-Conejero, J L; Gámez Cenzano, C

    2016-01-01

    The development of molecular and functional imaging with new imaging techniques such as computed tomography, magnetic resonance imaging, and positron emission tomography (PET) among others, has greatly improved the detection of tumors, tumor staging, and the detection of possible recurrences. Furthermore, the combination of these different imaging modalities and the continual development of radiotracers for PET have advanced our understanding and knowledge of the different pathophysiological processes in cancer, thereby helping to make treatment more efficacious, improving patients' quality of life, and increasing survival. PET is one of the imaging techniques that has attracted the most interest in recent years for its diagnostic capabilities. Its ability to anatomically locate pathologic foci of metabolic activity has revolutionized the detection and staging of many tumors, exponentially broadening its potential indications not only in oncology but also in other fields such as cardiology, neurology, and inflammatory and infectious diseases.

  17. Newer positron emission tomography radiopharmaceuticals for radiotherapy planning: an overview

    PubMed Central

    Mukherjee, Anirban

    2016-01-01

    Positron emission tomography-computed tomography (PET-CT) has changed cancer imaging in the last decade, for better. It can be employed for radiation treatment planning of different cancers with improved accuracy and outcomes as compared to conventional imaging methods. 18F-fluorodeoxyglucose remains the most widely used though relatively non-specific cancer imaging PET tracer. A wide array of newer PET radiopharmaceuticals has been developed for targeted imaging of different cancers. PET-CT with such new PET radiopharmaceuticals has also been used for radiotherapy planning with encouraging results. In the present review we have briefly outlined the role of PET-CT with newer radiopharmaceuticals for radiotherapy planning and briefly reviewed the available literature in this regard. PMID:26904575

  18. 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.

  19. 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

  20. Cardiac emission tomography in patients using 201thallium. A new technique for perfusion scintigraphy.

    PubMed

    Dymond, D S; Stone, D L; Elliott, A T; Britton, K E; Spurrell, R A

    1979-06-01

    The distribution of 201thallium (Tl) in the myocardium has been studied by the new technique of emission tomography, and compared with standard gamma camera images in 5 patients. Tomographic imaging was carried out using a dual-detector scanner operated under the single-photon technique. Initial results have been promising, with visualisation of resting perfusion defects in patients with recent infarction and those with ventricular aneurysms. Emission tomography has also been performed at exercise, and has shown tracer deficits in the distribution of significant coronary stenoses. This new approach to myocardial perfusion scintigraphy may lead to improved sensitivity for detecting apical and inferior wall abnormalities by providing depth information not available from a conventional two-dimensional image. PMID:315854

  1. 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.

  2. 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.

  3. Application of Computer Tomography for Life Detection

    NASA Technical Reports Server (NTRS)

    Tsapin, A.; Nealson, K.

    2001-01-01

    Perhaps one of the most fundamentally difficult challenges facing those who would search for life is that of scale determination. Spatial scales of life on Earth range over more than 15 orders of magnitude in mass and volume, and more than 8 orders of magnitude in 2 dimensional space. If the distribution of life is sparse in comparison to the background on which it is found, then the choice of the right scale is critical to finding that life. But how does one identify the proper scale? To put this in other words, how does one recognize the "haystacks" in which the needles (biosignatures and evidence of life) might be most profitably searched for? The problem is further exacerbated when conditions get extreme because much of the life moves from the clement surface environment into the pores and more clement environments inside of rocks, minerals and soils. Once encased in their lithic homes, these microbes become nearly impossible to study by standard techniques because of the opacity of the rocks. It is this problem that we propose to address in the work proposed here. Computer Tomography (CT) has been a very valuable tool in medicine, where the best resolution available has typically been of the order of about 0.5 mm. However, to adapt the approach for life detection of microbial endoliths, the resolution needs to be moved to the micrometer and even submicrometer levels. Thus for the studies proposed here, we begin with a commercially available instrument that can yield resolution of approximately 10 micrometers. The rational for this is twofold: first, this is the "state of the art" in laboratory instruments; and second, that while the usual size of a microbial cell is about 1 micron, microorganisms tend to live in communities that usually exceed the 10 micrometer size range. The resolution also depends on the sample size itself, so having a small lab instrument into which small samples can be placed will be beneficial to the resolution. We have now used several

  4. Clinical experience with the first combined positron emission tomography/computed tomography scanner in Australia.

    PubMed

    Lau, W F Eddie; Binns, David S; Ware, Robert E; Ramdave, Shakher; Cachin, Florent; Pitman, Alexander G; Hicks, Rodney J

    2005-02-21

    Metabolic imaging with fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is increasing rapidly worldwide because of superior accuracy compared with conventional non-invasive techniques used for evaluating cancer. Limited anatomical information from FDG-PET images alone dictates that complementary use with structural imaging is required to optimise benefit. Recently, combined positron emission tomography/computed tomography (PET/CT) scanners have overtaken standalone PET scanners as the most commonly purchased PET devices. We describe our experience of over 5500 scans performed since the first PET/CT scanner in Australia was commissioned at the Peter MacCallum Cancer Centre (PMCC), Melbourne, in January 2002. Clinical indications for PET/CT scans performed at PMCC largely reflect current Medicare reimbursement policy. Advantages of PET/CT include greater patient comfort and higher throughput, greater diagnostic certainty and accuracy, improved biopsy methods, and better treatment planning. We believe PET/CT will underpin more effective and efficient imaging paradigms for many common tumours, and lead to a decrease in imaging costs. PMID:15720173

  5. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  6. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

    PubMed

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results. PMID:27625897

  7. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results.

  8. Detect fugitive emissions with lasers

    SciTech Connect

    Frish, M.B.; Melnyk, J.M.

    1996-05-01

    Environmental and safety considerations are compelling refineries to monitor fugitive emissions of several listed compounds. Fugitive emissions often indicate a non-optimized process, equipment failure (pumps, valves, flanges, etc.) or potential health hazards. To improve safety, emission monitors must be capable of notifying the plant operator of an emission and its concentration. These units should have a response time and sufficient sensitivity to alert repair crews or to automatically initiate emergency mitigation procedures. Important refinery applications include worker safety and process optimization in and around: HF alkylation units; HF storage areas; sulfur recovery plants; and sour gas processing plants. Using open path monitors (OPMs), refiners can detect hazardous components` concentrations in process areas or at the fenceline. Incorporating near infrared, tunable diode laser spectroscopy, OPMs continuously measure and report trace concentrations of selected gas species such as H{sub 2}S, HF, HCl, CO, CO{sub 2}, HCN, H{sub 2}O, NH{sub 3} and CH{sub 4}. The laser`s wavelength identifies the specific gas monitored. Changing the laser to a different output wavelength allows other gases to be monitored.

  9. 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

  10. Unusual case of infantile fibrosarcoma evaluated on F-18 fluorodeoxyglucose positron emission tomography-computed tomography

    PubMed Central

    Bedmutha, Akshay; Singh, Natasha; Shivdasani, Divya; Gupta, Nitin

    2016-01-01

    Infantile fibrosarcoma (IFS) is a rare soft-tissue sarcoma originating from extremities and occasionally from axial soft tissue. The prognosis is good with favorable long-term survival. It is rarely metastasizing tumor, the chances being lesser with IFS originating from extremities. Use of neoadjuvant chemotherapy (NACT) as a treatment regime further reduces the chances of local relapse and distant metastasis. The organs commonly affected in metastatic IFS are lungs and lymph nodes. We report an unusual case of an IFS originating from extremity, which received NACT, yet presented with an early metastatic disease involving soft tissues and sparing lungs and lymph nodes, as demonstrated on fluorodeoxyglucose positron emission tomography-computed tomography. PMID:27385891

  11. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography

    PubMed Central

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  12. Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Fernø, M. A.; Gauteplass, J.; Hauge, L. P.; Abell, G. E.; Adamsen, T. C. H.; Graue, A.

    2015-09-01

    Here we show for the first time the combined positron emission tomography (PET) and computed tomography (CT) imaging of flow processes within porous rocks to quantify the development in local fluid saturations. The coupling between local rock structure and displacement fronts is demonstrated in exploratory experiments using this novel approach. We also compare quantification of 3-D temporal and spatial water saturations in two similar CO2 storage tests in sandstone imaged separately with PET and CT. The applicability of each visualization technique is evaluated for a range of displacement processes, and the favorable implementation of combining PET/CT for laboratory core analysis is discussed. We learn that the signal-to-noise ratio (SNR) is over an order of magnitude higher for PET compared with CT for the studied processes.

  13. A case of sarcoidosis diagnosed by positron emission tomography/computed tomography.

    PubMed

    Aksoy, Sabire Yilmaz; Özdemir, Elif; Sentürk, Aysegül; Türkölmez, Seyda

    2016-01-01

    Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis. PMID:27385890

  14. Spatial emission tomography reconstruction using Pitman-Yor process

    SciTech Connect

    Fall, Mame Diarra; Mohammad-Djafari, Ali; Barat, Eric; Comtat, Claude

    2009-12-08

    In this paper, we address the problem of emission tomography spatial reconstruction in three dimensions following a Bayesian nonparametric approach. Our model makes use of a generalization of the Dirichlet process called Pitman-Yor process. The problem in this approach is to deal with the infinite representation of the distribution in the inference. So we propose an efficient Markov Chain Monte-Carlo sampling scheme which is able to generate samples from the posterior distribution of the activity distribution. An application to 3D-PET reconstruction is presented.

  15. The statistical efficiency of filtered backprojection in emission tomography

    SciTech Connect

    Kuruc, A.

    1995-09-25

    While there has been much interest in developing tomographic reconstruction algorithms that are more statistically efficient than filtered backprojection (FB), the degree of improvement possible has not been well understood. We present an algorithm-independent theory of statistical accuracy attainable in emission tomography that provides a geometrical interpretation of the statistical efficiency of FB. Our analysis shows that, in general, one can build unbiased estimators with smaller variance than FB. The improvement in performance is obtained by exploiting the range properties of the Radon transform.

  16. Quantitative simultaneous positron emission tomography and magnetic resonance imaging

    PubMed Central

    Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G.; Kolnick, Aleksandra L.; El Fakhri, Georges

    2014-01-01

    Abstract. Simultaneous positron emission tomography and magnetic resonance imaging (PET-MR) is an innovative and promising imaging modality that is generating substantial interest in the medical imaging community, while offering many challenges and opportunities. In this study, we investigated whether MR surface coils need to be accounted for in PET attenuation correction. Furthermore, we integrated motion correction, attenuation correction, and point spread function modeling into a single PET reconstruction framework. We applied our reconstruction framework to in vivo animal and patient PET-MR studies. We have demonstrated that our approach greatly improved PET image quality. PMID:26158055

  17. Studying the pulmonary circulation with positron emission tomography

    SciTech Connect

    Schuster, D.P.; Mintun, M.A.

    1988-01-01

    Positron emission tomography and appropriately labeled, short-lived radiopharmaceuticals can be used to study a variety of physiologic processes within the lung. Recently, methods have been developed to measure regional pulmonary blood flow and pulmonary vascular permeability to protein macromolecules. The advantages of these techniques include accurate quantitation, regional data available in an image format, noninvasiveness, and repeatability. These methods have recently been applied to studies of hypoxic vasoconstriction, pulmonary edema, and chronic obstructive lung disease in man and large experimental animals. Although the technology is complex and requires the integration of people from a variety of disciplines, these methods offer a unique opportunity to study in vivo lung physiology.

  18. A Semiconductor-Based Positron Emission Tomography System

    NASA Astrophysics Data System (ADS)

    Oxley, D. C.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Grint, A. N.; Harkness, L. J.; Jones, M.; Judson, D. S.; Nolan, P. J.; Slee, M.; Unsworth, C.; Lazarus, I. H.

    2009-12-01

    This paper shall summarize the research conducted employing the high-purity germanium based small animal imaging system, SmartPET (SMall Animal Reconstructive Tomograph for Positron Emission Tomography). Geant4 simulations of the experimental setup were carried out in order to derive novel analysis procedures and quantify the system limitations. In this paper, we will focus on a gamma ray tracking approach devised to overcome germanium's high Compton scattering cross-section and on imaging challenging and complex phantom geometries. The potential of the developed tools and of the system itself will be discussed.

  19. Clinical Utility of Positron Emission Tomography Magnetic Resonance Imaging (PET-MRI) in Gastrointestinal Cancers.

    PubMed

    Matthews, Robert; Choi, Minsig

    2016-01-01

    Anatomic imaging utilizing both CT (computed tomography) and MRI (magnetic resonance imaging) limits the assessment of cancer metastases in lymph nodes and distant organs while functional imaging like PET (positron emission tomography) scan has its limitation in spatial resolution capacity. Hybrid imaging utilizing PET-CT and PET-MRI are novel imaging modalities that are changing the current landscape in cancer diagnosis, staging, and treatment response. MRI has shown to have higher sensitivity in soft tissue, head and neck pathology, and pelvic disease, as well as, detecting small metastases in the liver and bone compared to CT. Combining MRI with PET allows for detection of metastases that may have been missed with current imaging modalities. In this review, we will examine the clinical utility of FDG PET-MRI in the diagnosis and staging of gastrointestinal cancers with focus on esophageal, stomach, colorectal, and pancreatic cancers. We will also explore its role in treatment response and future directions associated with it.

  20. Multiparametric [18F]Fluorodeoxyglucose/ [18F]Fluoromisonidazole Positron Emission Tomography/ Magnetic Resonance Imaging of Locally Advanced Cervical Cancer for the Non-Invasive Detection of Tumor Heterogeneity: A Pilot Study

    PubMed Central

    Andrzejewski, Piotr; Baltzer, Pascal; Polanec, Stephan H.; Sturdza, Alina; Georg, Dietmar; Helbich, Thomas H.; Karanikas, Georgios; Grimm, Christoph; Polterauer, Stephan; Poetter, Richard; Wadsak, Wolfgang; Mitterhauser, Markus; Georg, Petra

    2016-01-01

    Objectives To investigate fused multiparametric positron emission tomography/magnetic resonance imaging (MP PET/MRI) at 3T in patients with locally advanced cervical cancer, using high-resolution T2-weighted, contrast-enhanced MRI (CE-MRI), diffusion-weighted imaging (DWI), and the radiotracers [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fluoromisonidazol ([18F]FMISO) for the non-invasive detection of tumor heterogeneity for an improved planning of chemo-radiation therapy (CRT). Materials and Methods Sixteen patients with locally advanced cervix were enrolled in this IRB approved and were examined with fused MP [18F]FDG/ [18F]FMISO PET/MRI and in eleven patients complete data sets were acquired. MP PET/MRI was assessed for tumor volume, enhancement (EH)-kinetics, diffusivity, and [18F]FDG/ [18F]FMISO-avidity. Descriptive statistics and voxel-by-voxel analysis of MRI and PET parameters were performed. Correlations were assessed using multiple correlation analysis. Results All tumors displayed imaging parameters concordant with cervix cancer, i.e. type II/III EH-kinetics, restricted diffusivity (median ADC 0.80x10-3mm2/sec), [18F]FDG- (median SUVmax16.2) and [18F]FMISO-avidity (median SUVmax3.1). In all patients, [18F]FMISO PET identified the hypoxic tumor subvolume, which was independent of tumor volume. A voxel-by-voxel analysis revealed only weak correlations between the MRI and PET parameters (0.05–0.22), indicating that each individual parameter yields independent information and the presence of tumor heterogeneity. Conclusion MP [18F]FDG/ [18F]FMISO PET/MRI in patients with cervical cancer facilitates the acquisition of independent predictive and prognostic imaging parameters. MP [18F]FDG/ [18F]FMISO PET/MRI enables insights into tumor biology on multiple levels and provides information on tumor heterogeneity, which has the potential to improve the planning of CRT. PMID:27167829

  1. Positron Emission Tomography imaging with the SmartPET system

    NASA Astrophysics Data System (ADS)

    Cooper, R. J.; Boston, A. J.; Boston, H. C.; Cresswell, J. R.; Grint, A. N.; Harkness, L. J.; Nolan, P. J.; Oxley, D. C.; Scraggs, D. P.; Mather, A. R.; Lazarus, I.; Simpson, J.

    2009-07-01

    The Small Animal Reconstruction Tomograph for Positron Emission Tomography (SmartPET) project is the development of a small animal Positron Emission Tomography (PET) demonstrator based on the use of High-Purity Germanium (HPGe) detectors and state of the art digital electronics. The experimental results presented demonstrate the current performance of this unique system. By performing high precision measurements of one of the SmartPET HPGe detectors with a range of finely collimated gamma-ray beams the response of the detector as a function of gamma-ray interaction position has been quantified, facilitating the development of parametric Pulse Shape Analysis (PSA) techniques and algorithms for the correction of imperfections in detector performance. These algorithms have then been applied to data from PET imaging measurements using two such detectors in conjunction with a specially designed rotating gantry. In this paper we show how the use of parametric PSA approaches allows over 60% of coincident events to be processed and how the nature and complexity of an event has direct implications for the quality of the resulting image.

  2. Positron Emission Tomography for the Assessment of Myocardial Viability

    PubMed Central

    2010-01-01

    waiting lists. The third option, revascularization, is used to restore the flow of blood to the heart via coronary artery bypass grafting (CABG) or through minimally invasive percutaneous coronary interventions (balloon angioplasty and stenting). Both methods, however, are associated with important perioperative risks including mortality, so it is essential to properly select patients for this procedure. Myocardial Viability Left ventricular dysfunction may be permanent if a myocardial scar is formed, or it may be reversible after revascularization. Reversible LV dysfunction occurs when the myocardium is viable but dysfunctional (reduced contractility). Since only patients with dysfunctional but viable myocardium benefit from revascularization, the identification and quantification of the extent of myocardial viability is an important part of the work-up of patients with heart failure when determining the most appropriate treatment path. Various non-invasive cardiac imaging modalities can be used to assess patients in whom determination of viability is an important clinical issue, specifically: dobutamine echocardiography (echo), stress echo with contrast, SPECT using either technetium or thallium, cardiac magnetic resonance imaging (cardiac MRI), and positron emission tomography (PET). Dobutamine Echocardiography Stress echocardiography can be used to detect viable myocardium. During the infusion of low dose dobutamine (5 – 10 μg/kg/min), an improvement of contractility in hypokinetic and akentic segments is indicative of the presence of viable myocardium. Alternatively, a low-high dose dobutamine protocol can be used in which a biphasic response characterized by improved contractile function during the low-dose infusion followed by a deterioration in contractility due to stress induced ischemia during the high dose dobutamine infusion (dobutamine dose up to 40 ug/kg/min) represents viable tissue. Newer techniques including echocardiography using contrast agents

  3. Co-registration of glucose metabolism with positron emission tomography and vascularity with fluorescent diffuse optical tomography in mouse tumors

    PubMed Central

    2012-01-01

    Background Bimodal molecular imaging with fluorescence diffuse optical tomography (fDOT) and positron emission tomography (PET) has the capacity to provide multiple molecular information of mouse tumors. The objective of the present study is to co-register fDOT and PET molecular images of tumors in mice automatically. Methods The coordinates of bimodal fiducial markers (FM) in regions of detection were automatically detected in planar optical images (x, y positions) in laser pattern optical surface images (z position) and in 3-D PET images. A transformation matrix was calculated from the coordinates of the FM in fDOT and in PET and applied in order to co-register images of mice bearing neuroendocrine tumors. Results The method yielded accurate non-supervised co-registration of fDOT and PET images. The mean fiducial registration error was smaller than the respective voxel sizes for both modalities, allowing comparison of the distribution of contrast agents from both modalities in mice. Combined imaging depicting tumor metabolism with PET-[18 F]2-deoxy-2-fluoro-d-glucose and blood pool with fDOT demonstrated partial overlap of the two signals. Conclusions This automatic method for co-registration of fDOT with PET and other modalities is efficient, simple and rapid, opening up multiplexing capacities for experimental in vivo molecular imaging. PMID:22564761

  4. Simulation study of respiratory-induced errors in cardiac positron emission tomography/computed tomography

    SciTech Connect

    Fitzpatrick, Gianna M.; Wells, R. Glenn

    2006-08-15

    Heart disease is a leading killer in Canada and positron emission tomography (PET) provides clinicians with in vivo metabolic information for diagnosing heart disease. Transmission data are usually acquired with {sup 68}Ge, although the advent of PET/CT scanners has made computed tomography (CT) an alternative option. The fast data acquisition of CT compared to PET may cause potential misregistration problems, leading to inaccurate attenuation correction (AC). Using Monte Carlo simulations and an anthropomorphic dynamic computer phantom, this study determines the magnitude and location of respiratory-induced errors in radioactivity uptake measured in cardiac PET/CT. A homogeneous tracer distribution in the heart was considered. The AC was based on (1) a time-averaged attenuation map (2) CT maps from a single phase of the respiratory cycle, and (3) CT maps phase matched to the emission data. Circumferential profiles of the heart uptake were compared and differences of up to 24% were found between the single-phase CT-AC method and the true phantom values. Simulation results were supported by a PET/CT canine study which showed differences of up to 10% in the heart uptake in the lung-heart boundary region when comparing {sup 68}Ge- to CT-based AC with the CT map acquired at end inhalation.

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

    PubMed

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

    2016-01-01

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

  6. 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

  7. Bayesian image reconstruction for improving detection performance of muon tomography.

    PubMed

    Wang, Guobao; Schultz, Larry J; Qi, Jinyi

    2009-05-01

    Muon tomography is a novel technology that is being developed for detecting high-Z materials in vehicles or cargo containers. Maximum likelihood methods have been developed for reconstructing the scattering density image from muon measurements. However, the instability of maximum likelihood estimation often results in noisy images and low detectability of high-Z targets. In this paper, we propose using regularization to improve the image quality of muon tomography. We formulate the muon reconstruction problem in a Bayesian framework by introducing a prior distribution on scattering density images. An iterative shrinkage algorithm is derived to maximize the log posterior distribution. At each iteration, the algorithm obtains the maximum a posteriori update by shrinking an unregularized maximum likelihood update. Inverse quadratic shrinkage functions are derived for generalized Laplacian priors and inverse cubic shrinkage functions are derived for generalized Gaussian priors. Receiver operating characteristic studies using simulated data demonstrate that the Bayesian reconstruction can greatly improve the detection performance of muon tomography.

  8. Simultaneous iterative reconstruction for emission and attenuation images in positron emission tomography.

    PubMed

    Glatting, G; Wuchenauer, M; Reske, S N

    2000-09-01

    The quality of the attenuation correction strongly influences the outcome of the reconstructed emission scan in positron emission tomography. Usually the attenuation correction factors are calculated from the transmission and blank scan and thereafter applied during the reconstruction on the emission data. However, this is not an optimal treatment of the available data, because the emission data themselves contain additional information about attenuation: The optimal treatment must use this information for the determination of the attenuation correction factors. Therefore, our purpose is to investigate a simultaneous emission and attenuation image reconstruction using a maximum likelihood estimator, which takes the attenuation information in the emission data into account. The total maximum likelihood function for emission and transmission is used to derive a one-dimensional Newton-like algorithm for the calculation of the emission and attenuation image. Log-likelihood convergence, mean differences, and the mean of squared differences for the emission image and the attenuation correction factors of a mathematical thorax phantom were determined and compared. As a result we obtain images improved with respect to log likelihood in all cases and with respect to our figures of merit in most cases. We conclude that the simultaneous reconstruction can improve the performance of image reconstruction.

  9. Plasma Emission Profile Recreation using Soft X-Ray Tomography

    NASA Astrophysics Data System (ADS)

    Page, J. W.; Mauel, M. E.; Levesque, J. P.

    2015-11-01

    With sufficient views from multiple diode arrays, soft X-ray tomography is an invaluable plasma diagnostic because it is a non-perturbing method to reconstruct the emission within the interior of the plasma. In preparation for the installation of new SXR arrays in HBT-EP, we compute high-resolution tomographic reconstructions of discharges having kink-like structures that rotate nearly rigidly. By assuming a uniform angular mapping from the kink mode rotation, Δϕ ~ ωΔ t, a temporal sequence from a single 16-diode fan array represents as many as 16 x 100 independent views. We follow the procedure described by Wang and Granetz and use Bessel basis functions to take the inverse Radon transform. This transform is fit to our data using a least-squares method to estimate the internal SXR emissivity as a sum of polar functions. By varying different parameters of the transformation, we optimize the quality of our recreation of the emission profile and quantify how the reconstruction changes with the azimuthal order of the transform. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  10. SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY: COMPENSATION FOR CONSTANT ATTENUATION

    SciTech Connect

    Gullberg, Grant T.; Budinger, Thomas F.

    1980-06-01

    A back-projection of filtered projection (BKFIL) reconstruction algorithm is presented that is applicable to single-photon emission computed tomography (ECT) in the presence of a constant attenuating medium such as the brain. The filters used in transmission computed tomography (TCT) - comprised of a ramp multiplied by window functions - are modified so that the single-photon ECT filter is a function of the constant attenuation coefficient. The filters give good reconstruction results with sufficient angular and lateral sampling. With continuous samples the BKFIL algorithm has a point spread function that is the Hankel transform of the window function. The resolution and s tistical properties of the filters are demonstrated by various simulations. Statistical formulas for the reconstructed image show that the square of the percent-root-mean square uncertainty (%RMS) of the reconstruction is inversely proportional to the total measured counts. The results indicate that constant attenuation can be compensated for in single-photon ECT by using an attenuation-dependent filter that reconstructs the transverse section reliably. Computer time requirements are two times that of conventional TCT or positron ECT and there is no increase in memory requirements.

  11. 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.

  12. Respiratory motion correction in emission tomography image reconstruction.

    PubMed

    Reyes, Mauricio; Malandain, Grégoire; Koulibaly, Pierre Malick; González Ballester, Miguel A; Darcourt, Jacques

    2005-01-01

    In Emission Tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations and imprecise diagnosis. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested with improvements over the spatial activity distribution in lungs lesions, but with the disadvantages of requiring additional instrumentation or discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion correction directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the Maximum Likelihood Expectation Maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data.

  13. 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.

  14. Central Nervous System Drug Evaluation Using Positron Emission Tomography

    PubMed Central

    Maeda, Jun; Shimada, Hitoshi; Nogami, Tsuyoshi; Arakawa, Ryosuke; Takano, Harumasa; Higuchi, Makoto; Ito, Hiroshi; Okubo, Yoshiro; Suhara, Tetsuya

    2011-01-01

    In conventional pharmacological research in the field of mental disorders, pharmacological effect and dose have been estimated by ethological approach and in vitro data of affinity to the site of action. In addition, the frequency of administration has been estimated from drug kinetics in blood. However, there is a problem regarding an objective index of drug effects in the living body. Furthermore, the possibility that the concentration of drug in blood does not necessarily reflect the drug kinetics in target organs has been pointed out. Positron emission tomography (PET) techniques have made progress for more than 20 years, and made it possible to measure the distribution and kinetics of small molecule components in living brain. In this article, we focused on rational drug dosing using receptor occupancy and proof-of-concept of drugs in the drug development process using PET. PMID:23431048

  15. Simulation of Medical Imaging Systems: Emission and Transmission Tomography

    NASA Astrophysics Data System (ADS)

    Harrison, Robert L.

    Simulation is an important tool in medical imaging research. In patient scans the true underlying anatomy and physiology is unknown. We have no way of knowing in a given scan how various factors are confounding the data: statistical noise; biological variability; patient motion; scattered radiation, dead time, and other data contaminants. Simulation allows us to isolate a single factor of interest, for instance when researchers perform multiple simulations of the same imaging situation to determine the effect of statistical noise or biological variability. Simulations are also increasingly used as a design optimization tool for tomographic scanners. This article gives an overview of the mechanics of emission and transmission tomography simulation, reviews some of the publicly available simulation tools, and discusses trade-offs between the accuracy and efficiency of simulations.

  16. Brain abnormalities in murderers indicated by positron emission tomography.

    PubMed

    Raine, A; Buchsbaum, M; LaCasse, L

    1997-09-15

    Murderers pleading not guilty by reason of insanity (NGRI) are thought to have brain dysfunction, but there have been no previous studies reporting direct measures of both cortical and subcortical brain functioning in this specific group. Positron emission tomography brain imaging using a continuous performance challenge task was conducted on 41 murderers pleading not guilty by reason of insanity and 41 age- and sex-matched controls. Murderers were characterized by reduced glucose metabolism in the prefrontal cortex, superior parietal gyrus, left angular gyrus, and the corpus callosum, while abnormal asymmetries of activity (left hemisphere lower than right) were also found in the amygdala, thalamus, and medial temporal lobe. These preliminary findings provide initial indications of a network of abnormal cortical and subcortical brain processes that may predispose to violence in murderers pleading NGRI.

  17. Positron emission tomography (PET) advances in neurological applications

    NASA Astrophysics Data System (ADS)

    Sossi, V.

    2003-09-01

    Positron Emission Tomography (PET) is a functional imaging modality used in brain research to map in vivo neurotransmitter and receptor activity and to investigate glucose utilization or blood flow patterns both in healthy and disease states. Such research is made possible by the wealth of radiotracers available for PET, by the fact that metabolic and kinetic parameters of particular processes can be extracted from PET data and by the continuous development of imaging techniques. In recent years great advancements have been made in the areas of PET instrumentation, data quantification and image reconstruction that allow for more detailed and accurate biological information to be extracted from PET data. It is now possible to quantitatively compare data obtained either with different tracers or with the same tracer under different scanning conditions. These sophisticated imaging approaches enable detailed investigation of disease mechanisms and system response to disease and/or therapy.

  18. Studies of the brain cannabinoid system using positron emission tomography

    SciTech Connect

    Gatley, S.J.; Volkow, N.D.

    1995-10-01

    Studies using radiolabeled psychoactive drugs in conjunction with positron emission tomography (PET) have permitted the imaging of binding sites in the human brain. Similar studies of marijuana have been hampered by the unsuitability of radiolabeled THC for PET studies, and the current unavailability of other in vivo imaging agents for cannabinoid receptors. Recent developments in medicinal chemistry suggest that a PET radiotracer for cannabinoid receptors will soon become available. This chapter briefly reviews these developments, together with the results of PET studies of the effects of marijuana and other abused drugs on brain metabolism. It also reviews PET studies of cocaine binding sites, to demonstrate the kind of investigations that will be possible when a cannabinoid receptor PET radioligand becomes available.

  19. Differential diagnosis of depression: relevance of positron emission tomography

    SciTech Connect

    Schwartz, J.M.; Baxter, L.R. Jr.; Mazziotta, J.C.; Gerner, R.H.; Phelps, M.E.

    1987-09-11

    The proper differential diagnosis of depression is important. A large body of research supports the division of depressive illness into bipolar and unipolar subtypes with respect to demographics, genetics, treatment response, and neurochemical mechanisms. Optimal treatment is different for unipolar and bipolar depressions. Treating a patient with bipolar depression as one would a unipolar patient may precipitate a serious manic episode or possibly even permanent rapid cycling disorder. The clinical distinction between these disorders, while sometimes difficult, can often be achieved through an increased diagnostic suspicion concerning a personal or family history of mania. Positron emission tomography and the FDG method, which allow in vivo study of the glucose metabolic rates for discrete cerebral structures, provide new evidence that bipolar and unipolar depression are two different disorders.

  20. Chelators for copper radionuclides in positron emission tomography radiopharmaceuticals†

    PubMed Central

    Cai, Zhengxin; Anderson, Carolyn J.

    2014-01-01

    The development of chelating agents for copper radionuclides in positron emission tomography radiopharmaceuticals has been a highly active and important area of study in recent years. The rapid evolution of chelators has resulted in highly specific copper chelators that can be readily conjugated to biomolecules and efficiently radiolabeled to form stable complexes in vivo. Chelators are not only designed for conjugation to monovalent biomolecules but also for incorporation into multivalent targeting ligands such as theranostic nanoparticles. These advancements have strengthened the role of copper radionuclides in the fields of nuclear medicine and molecular imaging. This review emphasizes developments of new copper chelators that have most greatly advanced the field of copper-based radiopharmaceuticals over the past 5 years. PMID:24347474

  1. Positron emission tomography for the evaluation and treatment of cardiomyopathy.

    PubMed

    Shah, Palak; Choi, Brian G; Mazhari, Ramesh

    2011-06-01

    Congestive heart failure accounts for tremendous morbidity and mortality worldwide. There are numerous causes of cardiomyopathy, the most common of which is coronary artery disease. Positron emission tomography (PET) has an established and expanding role in the evaluation of patients with cardiomyopathy. The specific application of PET to hypertrophic cardiomyopathy, cardiac sarcoidosis, and diabetic cardiomyopathy has been studied extensively and promises to be a useful tool for managing these patients. Furthermore, evaluating the efficacy of standard treatments for congestive heart failure is important as health care costs continue to rise. Recently, there have been significant developments in the field of cardiovascular stem cell research. Familiarity with the mechanisms by which stem cells benefit patients with cardiovascular disease is the key to understanding these advances. Molecular imaging techniques including PET/CT imaging play an important role in monitoring stem cell therapy in both animals and humans. These noninvasive imaging techniques will be highlighted in this paper.

  2. Positron emission tomography in the study of hepatic encephalopathy.

    PubMed

    Lockwood, A H

    1998-12-01

    Positron-emission tomography (PET) is a quantitative technique that produces images of biological or physiological processes. The nature of the image depends on the tracer used: common tracers used to study HE include 18F-fluordeoxyglucose, a marker of glucose metabolism; 15O-water, a marker of cerebral blood flow; and 13N-ammonia, a marker of ammonia metabolism. Combined blood flow and ammonia metabolism studies can be used to calculate the permeability surface area product for ammonia at the blood brain barrier. To take full advantage of PET, the data should be analyzed using one of the several sophisticated image processing and analysis techniques that are available. Thus, PET is an ideal technique to evaluate ammonia metabolism and, because of a close linkage of blood flow and glucose metabolism with neural activity, to investigate the neural response to drugs and other treatments and to examine neural systems that mediate specific tasks that are impaired in patients with HE.

  3. Wilson's disease studied with FDG and positron emission tomography

    SciTech Connect

    Hawkins, R.A.; Mazziotta, J.C.; Phelps, M.E.

    1987-11-01

    Four patients with Wilson's disease and eight normal controls were studied with 2-deoxy-2-(/sup 18/F)fluoro-D-glucose (FDG) and positron emission tomography (PET). The patients had diffusely reduced glucose metabolism in all brain regions evaluated compared with controls, with the exception of the thalamus. The ratio of the cerebral metabolic rate for glucose in the lenticular nuclei to hemispheres declined from 1.23 (+/- 0.14 SD) in controls to 1.03 (+/- 0.06) (p less than 0.025) in Wilson's disease patients. Compared with Huntington's disease, the PET FDG results in Wilson's disease indicate relatively less focal involvement of the caudate nucleus, more severe focal changes in the lenticular nuclei, and more significant global changes in glucose metabolism.

  4. Bayesian reconstruction and use of anatomical a priori information for emission tomography

    SciTech Connect

    Bowsher, J.E.; Johnson, V.E.; Turkington, T.G.; Jaszczak, R.J.; Floyd, C.E. Jr.; Coleman, R.E.

    1996-10-01

    A Bayesian method is presented for simultaneously segmenting and reconstructing emission computed tomography (ECT) images and for incorporating high-resolution, anatomical information into those reconstructions. The anatomical information is often available from other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). The Bayesian procedure models the ECT radiopharmaceutical distribution as consisting of regions, such that radiopharmaceutical activity is similar throughout each region. It estimates the number of regions, the mean activity of each region, and the region classification and mean activity of each voxel. Anatomical information is incorporated by assigning higher prior probabilities to ECT segmentations in which each ECT region stays within a single anatomical region. This approach is effective because anatomical tissue type often strongly influences radiopharmaceutical uptake. The Bayesian procedure is evaluated using physically acquired single-photon emission computed tomography (SPECT) projection data and MRI for the three-dimensional (3-D) Hoffman brain phantom. A clinically realistic count level is used. A cold lesion within the brain phantom is created during the SPECT scan but not during the MRI to demonstrate that the estimation procedure can detect ECT structure that is not present anatomically.

  5. Integrated telemedicine applications and services for oncological positron emission tomography.

    PubMed

    Kontaxakis, George; Visvikis, Dimitris; Ohl, Roland; Sachpazidis, Ilias; Suarez, Juan Pablo; Selby, Peter; Cheze-Le Rest, Catherine; Santos, Andres; Ortega, Fernando; Diaz, Javier; Pan, Leyun; Strauss, Ludwig; Dimitrakopoulou-Strauss, Antonia; Sakas, Georgios; Pozo, Miguel Angel

    2006-01-01

    TENPET (Trans European Network for Positron Emission Tomography) aims to evaluate the provision of integrated teleconsultation and intelligent computer supported cooperative work services for clinical positron emission tomography (PET) in Europe at its current stage, as it is a multi-centre project financially supported by the European Commission (Information Society, eTEN Program). It addresses technological challenges by linking PET centres and developing supporting services that permit remote consultation between professionals in the field. The technological platform (CE-marked) runs on Win2000/NT/XP systems and incorporates advanced techniques for image visualization, analysis and fusion, as well as for interactive communication and message handling for off-line communications. Four PET Centres from Spain, France and Germany participate to the pilot system trials. The performance evaluation of the system is carried out via log files and user-filled questionnaires on the frequency of the teleconsultations, their duration and efficacy, quality of the images received, user satisfaction, as well as on privacy, ethical and security issues. TENPET promotes the co-operation and improved communication between PET practitioners that are miles away from their peers or on mobile units, offering options for second opinion and training and permitting physicians to remotely consult patient data if they are away from their centre. It is expected that TENPET will have a significant impact in the development of new skills by PET professionals and will support the establishment of peripheral PET units. To our knowledge, TENPET is the first telemedicine service specifically designed for oncological PET. This report presents the technical innovations incorporated in the TENPET platform and the initial pilot studies at real and diverse clinical environments in the field of oncology.

  6. Application of positron emission tomography/computed tomography in radiation treatment planning for head and neck cancers

    PubMed Central

    Awan, Musaddiq J; Siddiqui, Farzan; Schwartz, David; Yuan, Jiankui; Machtay, Mitchell; Yao, Min

    2015-01-01

    18-fluorodeoxygluocose positron emission tomography/computed tomography (18FDG-PET/CT) provides significant information in multiple settings in the management of head and neck cancers (HNC). This article seeks to define the additional benefit of PET/CT as related to radiation treatment planning for squamous cell carcinomas (SCCs) of the head and neck through a review of relevant literature. By helping further define both primary and nodal volumes, radiation treatment planning can be improved using PET/CT. Special attention is paid to the independent benefit of PET/CT in targeting mucosal primaries as well as in detecting nodal metastases. The utility of PET/CT is also explored for treatment planning in the setting of SCC of unknown primary as PET/CT may help define a mucosal target volume by guiding biopsies for examination under anesthesia thus changing the treatment paradigm and limiting the extent of therapy. Implications of the use of PET/CT for proper target delineation in patients with artifact from dental procedures are discussed and the impact of dental artifact on CT-based PET attenuation correction is assessed. Finally, comment is made upon the role of PET/CT in the high-risk post-operative setting, particularly in the context of radiation dose escalation. Real case examples are used in these settings to elucidate the practical benefits of PET/CT as related to radiation treatment planning in HNCs. PMID:26644824

  7. Pulmonary malignant melanoma with distant metastasis assessed by positron emission tomography-computed tomography.

    PubMed

    Kim, So Ri; Yoon, Ha-Yong; Jin, Gong Yong; Choe, Yeong Hun; Park, Seung Yong; Lee, Yong Chul

    2016-07-01

    Melanoma is a cutaneous malignant neoplasm of melanocytes. Primary malignant melanoma (MM) of the lung is very rare. Although previous reports have described the radiologic features of pulmonary MM, its rarity means that many factors are unknown. Thus, radiologic diagnosis is very difficult. Furthermore, there is little information regarding diagnostic application and/or the usefulness of [(18)F]-fluorine-2-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG-PET-CT) for primary pulmonary MM. A 69-year-old patient with a productive cough lasting three weeks was admitted to our hospital. Chest CT showed a large single mass with a multi-lobulated margin and homogeneous enhancement in the right upper lobe, which was subsequently diagnosed as a primary pulmonary MM with multiple metastases. On PET-CT images, the pulmonary mass and multiple bone lesions showed very increased uptakes of FDG. Considering that pulmonary metastasis from a mucocutaneous melanoma is the main differential diagnosis of primary pulmonary MM, systemic assessment of the whole body is more important than for other types of lung malignancies. This report introduces PET-CT as a useful diagnostic modality for pulmonary MM, especially in cases of distant multiple metastases. PMID:27385996

  8. Positron emission tomography / computerized tomography evaluation of primary Hodgkin's disease of liver.

    PubMed

    Gota, V S; Purandare, N C; Gujral, S; Shah, S; Nair, R; Rangarajan, V

    2009-01-01

    Occurrence of primary Hodgkin's lymphoma (PHL) of the liver is extremely rare. We report on a case of a 60-year-old male who presented with liver mass and B-symptomatology. Hepatoma or hepatic metastasis from a gastrointestinal primary was initially suspected. Tumor markers like AFP, CEA, Total PSA, and CA-19.9 were within normal limits. Positron Emission Tomography / Computerized Tomography (PET/CT) revealed a large hepatic lesion and a nodal mass in the porta hepatis. A liver biopsy was consistent with Hodgkin's lymphoma. There was complete regression of the hepatic lesion and evidence of shrinkage of the nodal mass following four cycles of chemotherapy. 18F Fluro -de-oxy Glucose (FDG) PET / CT in this case helped in establishing a primary hepatic lymphoma by demonstrating the absence of pathologically hypermetabolic foci in any other nodes or organs. PET / CT scan is a useful adjunct to conventional imaging and histopathology, not only to establish the initial diagnosis, but also to monitor treatment response in PHL.

  9. Role of positron emission tomography-computed tomography in non-small cell lung cancer

    PubMed Central

    Garg, Pankaj Kumar; Singh, Saurabh Kumar; Prakash, Gaurav; Jakhetiya, Ashish; Pandey, Durgatosh

    2016-01-01

    Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell carcinoma and small cell carcinoma are the main histological subtypes and constitutes around 85% and 15% of all lung cancer respectively. Multimodality treatment plays a key role in the successful management of lung cancer depending upon the histological subtype, stage of disease, and performance status. Imaging modalities play an important role in the diagnosis and accurate staging of the disease, in assessing the response to neoadjuvant therapy, and in the follow-up of the patients. Last decade has witnessed voluminous upsurge in the use of positron emission tomography-computed tomography (PET-CT); role of PET-CT has widened exponentially in the management of lung cancer. The present article reviews the role of 18-fluoro-deoxyglucose PET-CT in the management of non small cell lung cancer with emphasis on staging of the disease and the assessment of response to neoadjuvant therapy based on available literature. PMID:27018223

  10. Noise reduction in muon tomography for detecting high density objects

    NASA Astrophysics Data System (ADS)

    Benettoni, M.; Bettella, G.; Bonomi, G.; Calvagno, G.; Calvini, P.; Checchia, P.; Cortelazzo, G.; Cossutta, L.; Donzella, A.; Furlan, M.; Gonella, F.; Pegoraro, M.; Rigoni Garola, A.; Ronchese, P.; Squarcia, S.; Subieta, M.; Vanini, S.; Viesti, G.; Zanuttigh, P.; Zenoni, A.; Zumerle, G.

    2013-12-01

    The muon tomography technique, based on multiple Coulomb scattering of cosmic ray muons, has been proposed as a tool to detect the presence of high density objects inside closed volumes. In this paper a new and innovative method is presented to handle the density fluctuations (noise) of reconstructed images, a well known problem of this technique. The effectiveness of our method is evaluated using experimental data obtained with a muon tomography prototype located at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di Fisica Nucleare (INFN). The results reported in this paper, obtained with real cosmic ray data, show that with appropriate image filtering and muon momentum classification, the muon tomography technique can detect high density materials, such as lead, albeit surrounded by light or medium density material, in short times. A comparison with algorithms published in literature is also presented.

  11. EEG, transmission computed tomography, and positron emission tomography with fluorodeoxyglucose /sup 18/F. Their use in adults with gliomas

    SciTech Connect

    Newmark, M.E.; Theodore, W.H.; Sato, S.; De La Paz, R.; Patronas, N.; Brooks, R.; Jabbari, B.; Di Chiro, G.

    1983-10-01

    We evaluated the relationship between findings from EEG, transmission computed tomography (CT), and positron emission tomography in 23 adults with gliomas. The cortical metabolic rate was suppressed in patients with and without focal slowing. Focal delta activity was not related to involvement of gray or white matter. Rhythmic delta activity and focal attenuation of background amplitude on EEG, however, were correlated with involvement of the thalamus.

  12. Retroperitoneal Endometriosis: A Possible Cause of False Positive Finding at 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    PubMed Central

    Maffione, Anna Margherita; Panzavolta, Riccardo; Lisato, Laura Camilla; Ballotta, Maria; D'Isanto, Mariangela Zanforlini; Rubello, Domenico

    2015-01-01

    Endometriosis is a frequent and clinically relevant problem in young women. Laparoscopy is still the gold standard for the diagnosis of endometriosis, but frequently both morphologic and functional imaging techniques are involved in the diagnostic course before achieving a conclusive diagnosis. We present a case of a patient affected by infiltrating retroperitoneal endometriosis falsely interpreted as a malignant mass by contrast-enhanced magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography/computed tomography. PMID:26097425

  13. Attenuation correction in emission tomography using the emission data—A review

    PubMed Central

    Li, Yusheng

    2016-01-01

    The problem of attenuation correction (AC) for quantitative positron emission tomography (PET) had been considered solved to a large extent after the commercial availability of devices combining PET with computed tomography (CT) in 2001; single photon emission computed tomography (SPECT) has seen a similar development. However, stimulated in particular by technical advances toward clinical systems combining PET and magnetic resonance imaging (MRI), research interest in alternative approaches for PET AC has grown substantially in the last years. In this comprehensive literature review, the authors first present theoretical results with relevance to simultaneous reconstruction of attenuation and activity. The authors then look back at the early history of this research area especially in PET; since this history is closely interwoven with that of similar approaches in SPECT, these will also be covered. We then review algorithmic advances in PET, including analytic and iterative algorithms. The analytic approaches are either based on the Helgason–Ludwig data consistency conditions of the Radon transform, or generalizations of John’s partial differential equation; with respect to iterative methods, we discuss maximum likelihood reconstruction of attenuation and activity (MLAA), the maximum likelihood attenuation correction factors (MLACF) algorithm, and their offspring. The description of methods is followed by a structured account of applications for simultaneous reconstruction techniques: this discussion covers organ-specific applications, applications specific to PET/MRI, applications using supplemental transmission information, and motion-aware applications. After briefly summarizing SPECT applications, we consider recent developments using emission data other than unscattered photons. In summary, developments using time-of-flight (TOF) PET emission data for AC have shown promising advances and open a wide range of applications. These techniques may both remedy

  14. 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

  15. Combined computed tomography and fluorodeoxyglucose positron emission tomography in the diagnosis of prosthetic valve endocarditis: a case series

    PubMed Central

    2014-01-01

    Background The diagnosis of prosthetic valve endocarditis is challenging. The gold standard for prosthetic valve endocarditis diagnosis is trans-esophageal echocardiography. However, trans-esophageal echocardiography may result in negative findings or yield images difficult to differentiate from thrombus in patients with prosthetic valve endocarditis. Combined computed tomography and fluorodeoxyglucose positron emission tomography is a potentially promising diagnostic tool for several infectious conditions and it has also been employed in patients with prosthetic valve endocarditis but data are still scant. Case presentations We reviewed the charts of 6 patients with prosthetic aortic valves evaluated for suspicion of prosthetic valve endocarditis, at two different hospital, over a 3-year period. We found 3 patients with early-onset PVE cases and blood cultures yielding Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus lugdunensis, respectively; and 3 late-onset cases in the remaining 3 patients with isolation in the blood of Streptococcus bovis, Candida albicans and P. aeruginosa, respectively. Initial trans-esophageal echocardiography was negative in all the patients, while fluorodeoxyglucose positron emission tomography showed images suspicious for prosthetic valve endocarditis. In 4 out of 6 patients valve replacement was done with histology confirming the prosthetic valve endocarditis diagnosis. After an adequate course of antibiotic therapy fluorodeoxyglucose positron emission tomography showed resolution of prosthetic valve endocarditis in all the patients. Conclusion Our experience confirms the potential role of fluoroseoxyglucose positron emission tomography in the diagnosis and follow-up of prosthetic valve endocarditis. PMID:24418206

  16. Positron Emission Tomography for the Assessment of Myocardial Viability

    PubMed Central

    2005-01-01

    Executive Summary Objective The objective was to update the 2001 systematic review conducted by the Institute For Clinical Evaluative Sciences (ICES) on the use of positron emission tomography (PET) in assessing myocardial viability. The update consisted of a review and analysis of the research evidence published since the 2001 ICES review to determine the effectiveness and cost-effectiveness of PET in detecting left ventricular (LV) viability and predicting patient outcomes after revascularization in comparison with other noninvasive techniques. Background Left Ventricular Viability Heart failure is a complex syndrome that impairs the contractile ability of the heart to maintain adequate blood circulation, resulting in poor functional capacity and increased risk of morbidity and mortality. It is the leading cause of hospitalization in elderly Canadians. In more than two-thirds of cases, heart failure is secondary to coronary heart disease. It has been shown that dysfunctional myocardium resulting from coronary heart disease (CAD) may recover contractile function (i.e. considered viable). Dysfunctional but viable myocardium may have been stunned by a brief episode of ischemia, followed by restoration of perfusion, and may regain function spontaneously. It is believed that repetitive stunning results in hibernating myocardium that will only regain contractile function upon revascularization. For people with CAD and severe LV dysfunction (left ventricular ejection fraction [LVEF] <35%) refractory to medical therapy, coronary artery bypass and heart transplantation are the only treatment options. The opportunity for a heart transplant is limited by scarcityof donor hearts. Coronary artery bypass in these patients is associated with high perioperative complications; however, there is evidence that revascularization in the presence of dysfunctional but viable myocardium is associated with survival benefits and lower rates of cardiac events. The assessment of left

  17. Role of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Cytologically Indeterminate Thyroid Nodules

    PubMed Central

    Buyukdereli, Gulgun; Aktar, Yasemin; Kara, Ertan; Uguz, Aysun; Sonmez, Husnu

    2016-01-01

    Background: Thyroid nodules with indeterminate fine-needle aspiration biopsy (FNAB) results remain a diagnostic dilemma, because 70 - 85% of these nodules have been found to be benign after thyroid surgery. Objectives: The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the preoperative diagnosis of cytologically indeterminate nodules. Patients and Methods: Forty-six patients were included in this study. These individuals had undergone FDG PET/CTs for the preoperative evaluation of thyroid nodules with indeterminate FNAB results. The results of the preoperative PET/CT scans were compared with the postoperative pathological results and statistically analyzed. Results: Of the 46 patients included in our study, the histopathology of the surgical specimens revealed thyroid cancer in 17 individuals (37%, 17/46). The PET/CT scan showed a positive result in 27 patients. Of these, 16 patients (59.3%) were found to have thyroid carcinomas. In addition, the PET/CT scan was considered to be negative in 19 patients, 18 (94.7%) of whom had benign lesions. For the detection of malignant lesions, the values for the sensitivity and specificity, and the positive predictive and negative predictive values were 94%, 62%, 59%, and 95%, respectively. Conclusion: The FDG PET/CT showed a high sensitivity and a high negative predictive value for identifying malignancies in thyroid nodules with indeterminate FNAB results. Therefore, the FDG PET/CT may be a helpful tool in the clinical management of these nodules. When an FDG positive lesion is detected, further examination is recommended. PMID:27110335

  18. Positron emission tomography in the study of human tumors.

    PubMed

    Beaney, R P

    1984-10-01

    To increase our understanding of cancer and improve cancer treatment on a rational basis we need to identify both qualitative and quantitative differences between normal and neoplastic tissue. The multimodality approach to cancer treatment includes radiotherapy, chemotherapy, hyperthermia, and immunotherapy. Most of the data on which we base our therapeutic strategies have been derived from in vitro studies or animal tumor models. More information is required on the physiology of in vivo human tumors and their response to therapy. Positron emission tomography allows the regional tissue concentration of a positron emitting radionuclide to be measured in absolute units. If valid tracer models can be formulated that accurately describe the fate of an administered "biological" tracer then the physiological process under investigation can be measured quantitatively. The sequential inhalation of C15O2, 15O2, and 11CO allows regional tissue blood flow, oxygen utilization and blood volume to be measured in absolute units. Tissue perfusion, a measure of nutrient (eg, oxygen) supply, drug delivery, or a means of heat dissipation, is of immense importance to oncologists. The oxygen-15 technique has been used not only to study regional blood flow and oxygen utilization in both tumor and normal tissue but also their response to therapeutic intervention. In those studies were tracer models are thought to be less than complete (eg, due to insufficient biological data) then only a semiquantitative or qualitative assessment of the pathophysiological state may be possible. In this respect, tumor function has been characterized by the rate of uptake of 18F-2-deoxyglucose. This technique has provided a means of tumor grading and differentiating between radiation-induced tissue necrosis and tumor recurrence. Metabolic imaging with labeled amino acids appears particularly useful in the delineation of tumor extent. Blood brain barrier integrity and the pharmacokinetics of cytotoxic drugs

  19. Motion management in positron emission tomography/computed tomography for radiation treatment planning.

    PubMed

    Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gilardi, Maria Carla

    2012-09-01

    Hybrid positron emission tomography (PET)/computed tomography (CT) scanners combine, in a unique gantry, 2 of the most important diagnostic imaging systems, a CT and a PET tomograph, enabling anatomical (CT) and functional (PET) studies to be performed in a single study session. Furthermore, as the 2 scanners use the same spatial coordinate system, the reconstructed CT and PET images are spatially co-registered, allowing an accurate localization of the functional signal over the corresponding anatomical structure. This peculiarity of the hybrid PET/CT system results in improved tumor characterization for oncological applications, and more recently, it was found to be also useful for target volume definition (TVD) and treatment planning in radiotherapy (RT) applications. In fact, the use of combined PET/CT information has been shown to improve the RT treatment plan when compared with that obtained by a CT alone. A limiting factor to the accuracy of TVD by PET/CT is organ and tumor motion, which is mainly due to patient respiration. In fact, respiratory motion has a degrading effect on PET/CT image quality, and this is also critical for TVD, as it can lead to possible tumor missing or undertreatment. Thus, the management of respiratory motion is becoming an increasingly essential component in RT treatment planning; indeed, it has been recognized that the use of personalized motion information can improve TVD and, consequently, permit increased tumor dosage while sparing surrounding healthy tissues and organs at risk. This review describes the methods used for motion management in PET/CT for radiation treatment planning. The article covers the following: (1) problems caused by organ and lesion motion owing to respiration, and the artifacts generated on CT, PET, and PET/CT images; (2) data acquisition and processing techniques used to manage respiratory motion in PET/CT studies; and (3) the use of personalized motion information for TVD and radiation treatment planning.

  20. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  1. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast

    PubMed Central

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-01-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05).

  2. Relationship of computed tomography perfusion and positron emission tomography to tumour progression in malignant glioma

    SciTech Connect

    Yeung, Timothy P C; Yartsev, Slav; Lee, Ting-Yim; Wong, Eugene; He, Wenqing; Fisher, Barbara; VanderSpek, Lauren L; Macdonald, David; Bauman, Glenn

    2014-02-15

    Introduction: This study aimed to explore the potential for computed tomography (CT) perfusion and 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting sites of future progressive tumour on a voxel-by-voxel basis after radiotherapy and chemotherapy. Methods: Ten patients underwent pre-radiotherapy magnetic resonance (MR), FDG-PET and CT perfusion near the end of radiotherapy and repeated post-radiotherapy follow-up MR scans. The relationships between these images and tumour progression were assessed using logistic regression. Cross-validation with receiver operating characteristic (ROC) analysis was used to assess the value of these images in predicting sites of tumour progression. Results: Pre-radiotherapy MR-defined gross tumour; near-end-of-radiotherapy CT-defined enhancing lesion; CT perfusion blood flow (BF), blood volume (BV) and permeability-surface area (PS) product; FDG-PET standard uptake value (SUV); and SUV:BF showed significant associations with tumour progression on follow-up MR imaging (P < 0.0001). The mean sensitivity (±standard deviation), specificity and area under the ROC curve (AUC) of PS were 0.64 ± 0.15, 0.74 ± 0.07 and 0.72 ± 0.12 respectively. This mean AUC was higher than that of the pre-radiotherapy MR-defined gross tumour and near-end-of-radiotherapy CT-defined enhancing lesion (both AUCs = 0.6 ± 0.1, P ≤ 0.03). The multivariate model using BF, BV, PS and SUV had a mean AUC of 0.8 ± 0.1, but this was not significantly higher than the PS only model. Conclusion: PS is the single best predictor of tumour progression when compared to other parameters, but voxel-based prediction based on logistic regression had modest sensitivity and specificity.

  3. Quantitative Assessment of Radionuclide Uptake and Positron Emission Tomography-computed Tomography Image Contrast.

    PubMed

    Francis, Hasford; Amuasi, John Humphrey; Kwame, Kyere Augustine; Vangu, Mboyo Di Tamba

    2016-09-01

    Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). PMID:27650938

  4. Enhancement of positron emission tomography-computed tomography image quality using the principle of stochastic resonance

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Sharma, Punit; Singh, Harmandeep; Patel, Chetan; Sarkar, Kaushik; Kumar, Rakesh; Bal, Chandra Sekhar

    2014-01-01

    Purpose: Acquisition of higher counts improves visual perception of positron emission tomography-computed tomography (PET-CT) image. Larger radiopharmaceutical doses (implies more radiation dose) are administered to acquire this count in a short time period. However, diagnostic information does not increase after a certain threshold of counts. This study was conducted to develop a post processing method based on principle of “stochastic resonance” to improve visual perception of the PET-CT image having a required threshold counts. Materials and Methods: PET-CT images (JPEG file format) with low, medium, and high counts in the image were included in this study. The image was corrupted with the addition of Poisson noise. The amplitude of the Poisson noise was adjusted by dividing each pixel by a constant 1, 2, 4, 8, 16, and 32. The best amplitude of the noise that gave best images quality was selected based on high value of entropy of the output image, high value of structural similarity index and feature similarity index. Visual perception of the image was evaluated by two nuclear medicine physicians. Results: The variation in structural and feature similarity of the image was not appreciable visually, but statistically images deteriorated as the noise amplitude increases although maintaining structural (above 70%) and feature (above 80%) similarity of input images in all cases. We obtained the best image quality at noise amplitude “4” in which 88% structural and 95% feature similarity of the input images was retained. Conclusion: This method of stochastic resonance can be used to improve the visual perception of the PET-CT image. This can indirectly lead to reduction of radiation dose. PMID:25400362

  5. The role of positron emission tomography-computed tomography and magnetic resonance imaging in diagnosis and follow up of multiple myeloma

    PubMed Central

    Caers, Jo; Withofs, Nadia; Hillengass, Jens; Simoni, Paolo; Zamagni, Elena; Hustinx, Roland; Beguin, Yves

    2014-01-01

    Multiple myeloma is the second most common hematologic malignancy and occurs most commonly in elderly patients. Almost all multiple myeloma patients develop bone lesions in the course of their disease or have evidence of bone loss at initial diagnosis. Whole-body conventional radiography remains the gold standard in the diagnostic evaluation, but computed tomography, magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography are increasingly used as complementary techniques in the detection of bone lesions. Moreover, the number of lesions detected and the presence of extramedullary disease give strong prognostic information. These new techniques may help to assess treatment response in solitary plasmacytoma or in multiple myeloma. In this article, we review recent data on the different imaging techniques used at diagnosis and in the assessment of treatment response, and discuss some current issues. PMID:24688111

  6. Multidimensional characterization of an entangled photon-pair source via stimulated emission tomography.

    PubMed

    Fang, B; Liscidini, M; Sipe, J E; Lorenz, V O

    2016-05-01

    Using stimulated emission tomography, we characterize an entangled photon-pair source in the energy and polarization degrees of freedom, with a precision far exceeding what could be obtained by quantum state tomography. Through this multidimensional tomography we find that energy-polarization correlations are a cause of polarization-entanglement degradation, demonstrating that this technique provides useful information for source engineering and can accelerate the development of quantum information processing systems dependent on many degrees of freedom. PMID:27137611

  7. Regulation of the compounding of positron emission tomography drugs.

    PubMed

    Hung, J C

    2001-01-15

    Controversial aspects of the regulatory framework for compounding drug products used in positron emission tomography (PET) are discussed. The Food and Drug Administration Modernization Act of 1997 (FDAMA), which amends the Federal Food, Drug, and Cosmetic Act (FFDCA), required that FDA establish approval (new drug application [NDA] and abbreviated new drug application [ANDA]) procedures and current good manufacturing practice (CGMP) requirements for PET drugs; this seems to conflict with differentiation between manufacturing and compounding in FFDCA. Compounding by pharmacists is implied in the FDAMA section on PET, but specific mention of "pharmacist" needs to be included. Congress apparently did not intend for compounded PET drugs to be regulated differently from other drugs. Although FDA has waived NDA and ANDA fees for three PET radiopharmaceuticals, revision of FDAMA to exempt PET drug products from regulations placed on manufacturing is needed. Without relief from the current regulations, many academic PET centers are likely to close; this would violate FDAMA's stated intent of making PET available to patients at reasonable cost. Also problematic is FDAMA's prohibition of compounding "regularly or in inordinate amounts" a product that is commercially available; the common PET radiopharmaceutical fludeoxyglucose F 18 injection, for example, is commercially available. A sensible alternative to NDA or ANDA and CGMP requirements would be the enforcement of USP standards for PET drugs by state boards of pharmacy.

  8. Mathematical model of single-photon emission computed tomography

    SciTech Connect

    Clough, A.V.

    1986-01-01

    Single-photon emission computed tomography (SPECT) is a nuclear-medicine imaging technique that has been shown to provide clinically useful images of radionuclide distributions within the body. The problem of quantitative determination of tomographic activity images from a projection data set leads to a mathematical inverse problem which is formulated as an integral equation. The solution of this problem then depends on an accurate mathematical model as well as a reliable and efficient inversion algorithm. The effects of attenuation and Compton scatter within the body have been incorporated into the model in the hopes of providing a more physically realistic mathematical model. The attenuated Radon transform is the mathematical basis of SPECT. In this work, the case of constant attenuation is reviewed and a new proof of the Tretiak-Metz algorithm is presented. A space-domain version of the inverse attenuated Radon transform is derived. A special case of this transform that is applicable when the object is rotationally symmetric, and attenuated Abel transform is derived, and its inverse is found. A numerical algorithm for the implementation of the inverse attenuated Radon transform with constant attenuation is described and computer simulations are performed to demonstrate the results of the inversion procedure. With the use of the single-scatter approximation and an energy-windowed detector, the effects of Compton scatter are incorporated into the model. The data are then taken to be the sum of primary photons and single-scattered photons.

  9. European health telematics networks for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Kontaxakis, George; Pozo, Miguel Angel; Ohl, Roland; Visvikis, Dimitris; Sachpazidis, Ilias; Ortega, Fernando; Guerra, Pedro; Cheze-Le Rest, Catherine; Selby, Peter; Pan, Leyun; Diaz, Javier; Dimitrakopoulou-Strauss, Antonia; Santos, Andres; Strauss, Ludwig; Sakas, Georgios

    2006-12-01

    A pilot network of positron emission tomography centers across Europe has been setup employing telemedicine services. The primary aim is to bring all PET centers in Europe (and beyond) closer, by integrating advanced medical imaging technology and health telematics networks applications into a single, easy to operate health telematics platform, which allows secure transmission of medical data via a variety of telecommunications channels and fosters the cooperation between professionals in the field. The platform runs on PCs with Windows 2000/XP and incorporates advanced techniques for image visualization, analysis and fusion. The communication between two connected workstations is based on a TCP/IP connection secured by secure socket layers and virtual private network or jabber protocols. A teleconsultation can be online (with both physicians physically present) or offline (via transmission of messages which contain image data and other information). An interface sharing protocol enables online teleconsultations even over low bandwidth connections. This initiative promotes the cooperation and improved communication between nuclear medicine professionals, offering options for second opinion and training. It permits physicians to remotely consult patient data, even if they are away from the physical examination site.

  10. Geoscientific process monitoring with positron emission tomography (GeoPET)

    NASA Astrophysics Data System (ADS)

    Kulenkampff, Johannes; Gründig, Marion; Zakhnini, Abdelhamid; Lippmann-Pipke, Johanna

    2016-08-01

    Transport processes in geomaterials can be observed with input-output experiments, which yield no direct information on the impact of heterogeneities, or they can be assessed by model simulations based on structural imaging using µ-CT. Positron emission tomography (PET) provides an alternative experimental observation method which directly and quantitatively yields the spatio-temporal distribution of tracer concentration. Process observation with PET benefits from its extremely high sensitivity together with a resolution that is acceptable in relation to standard drill core sizes. We strongly recommend applying high-resolution PET scanners in order to achieve a resolution on the order of 1 mm. We discuss the particularities of PET applications in geoscientific experiments (GeoPET), which essentially are due to high material density. Although PET is rather insensitive to matrix effects, mass attenuation and Compton scattering have to be corrected thoroughly in order to derive quantitative values. Examples of process monitoring of advection and diffusion processes with GeoPET illustrate the procedure and the experimental conditions, as well as the benefits and limits of the method.

  11. Florbetapir positron emission tomography and cerebrospinal fluid biomarkers

    PubMed Central

    Hake, Ann; Trzepacz, Paula T.; Wang, Shufang; Yu, Peng; Case, Michael; Hochstetler, Helen; Witte, Michael M.; Degenhardt, Elisabeth K.; Dean, Robert A.

    2015-01-01

    Background We evaluated the relationship between florbetapir-F18 positron emission tomography (FBP PET) and cerebrospinal fluid (CSF) biomarkers. Methods Alzheimer’s Disease Neuroimaging Initiative (ADNI)-GO/2 healthy control (HC), mild cognitive impairment (MCI), and Alzheimer’s disease (AD) dementia subjects with clinical measures and CSF collected ±90 days of FBP PET data were analyzed using correlation and logistic regression. Results In HC and MCI subjects, FBP PET anterior and posterior cingulate and composite standard uptake value ratios correlated with CSF amyloid beta (Aβ1-42) and tau/Aβ1-42 ratios. Using logistic regression, Aβ1-42, total tau (t-tau), phosphorylated tau181P (p-tau), and FBP PET composite each differentiated HC versus AD. Aβ1-42 and t-tau distinguished MCI versus AD, without additional contribution by FBP PET. Total tau and p-tau added discriminative power to FBP PET when classifying HC versus AD. Conclusion Based on cross-sectional diagnostic groups, both amyloid and tau measures distinguish healthy from demented subjects. Longitudinal analyses are needed. PMID:25916563

  12. Eyeblink Conditioning in Healthy Adults: A Positron Emission Tomography Study

    PubMed Central

    Andreasen, Nancy C.; Liu, Dawei; Freeman, John H.; Boles Ponto, Laura L.; O’Leary, Daniel S.

    2013-01-01

    Eyeblink conditioning is a paradigm commonly used to investigate the neural mechanisms underlying motor learning. It involves the paired presentation of a toneconditioning stimulus which precedes and co-terminates with an airpuff unconditioned stimulus. Following repeated paired presentations a conditioned eyeblink develops which precedes the airpuff. This type of learning has been intensively studied and the cerebellum is known to be essential in both humans and animals. The study presented here was designed to investigate the role of the cerebellum during eyeblink conditioning in humans using positron emission tomography (PET). The sample includes 20 subjects (10 male and 10 female) with an average age of 29.2 years. PET imaging was used to measure regional cerebral blood flow (rCBF) changes occurring during the first, second, and third blocks of conditioning. In addition, stimuli-specific rCBF to unpaired tones and airpuffs (“pseudoconditioning”) was used as a baseline level that was subtracted from each block. Conditioning was performed using three, 15-trial blocks of classical eyeblink conditioning with the last five trials in each block imaged. As expected, subjects quickly acquired conditioned responses. A comparison between the conditioning tasks and the baseline task revealed that during learning there was activation of the cerebellum and recruitment of several higher cortical regions. Specifically, large peaks were noted in cerebellar lobules IV/V, the frontal lobes, and cingulate gyri. PMID:22430943

  13. 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)

  14. 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.

  15. The Next Generation of Positron Emission Tomography Radiopharmaceuticals in Oncology

    PubMed Central

    Rice, Samuel L.; Roney, Celeste A.; Daumar, Pierre; Lewis, Jason S.

    2015-01-01

    Although 18F-fluorodeoxyglucose (18F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively. PMID:21624561

  16. The next generation of positron emission tomography radiopharmaceuticals in oncology.

    PubMed

    Rice, Samuel L; Roney, Celeste A; Daumar, Pierre; Lewis, Jason S

    2011-07-01

    Although (18)F-fluorodeoxyglucose ((18)F-FDG) is still the most widely used positron emission tomography (PET) radiotracer, there are a few well-known limitations to its use. The last decade has seen the development of new PET probes for in vivo visualization of specific molecular targets, along with important technical advances in the production of positron-emitting radionuclides and their related labeling methods. As such, a broad range of new PET tracers are in preclinical development or have recently entered clinical trials. The topics covered in this review include labeling methods, biological targets, and the most recent preclinical or clinical data of some of the next generation of PET radiopharmaceuticals. This review, which is by no means exhaustive, has been separated into sections related to the PET radionuclide used for radiolabeling: fluorine-18, for the labeling of agents such as FACBC, FDHT, choline, and Galacto-RGD; carbon-11, for the labeling of choline; gallium-68, for the labeling of peptides such as DOTATOC and bombesin analogs; and the long-lived radionuclides iodine-124 and zirconium-89 for the labeling of monoclonal antibodies cG250, and J591 and trastuzumab, respectively.

  17. Positron Emission Tomography Detector Development for Plant Biology

    SciTech Connect

    Weisenberger, A G; McKisson, J; Stolin, A; Zorn, C; Howell, C R; Crowell, A S; Reid, C D; Majewski, S; Smith, M F

    2010-01-01

    There are opportunities for the development of new tools to advance plant biology research through the use of radionuclides. Thomas Jefferson National Accelerator Facility, Duke University, West Virginia University and the University of Maryland are collaborating on the development of radionuclide imaging technologies to facilitate plant biology research. Biological research into optimizing plant productivity under various environmental constraints, biofuel and carbon sequestration research are areas that could potentially benefit from new imaging technologies. Using 11CO2 tracers, the investigators at Triangle University Nuclear Laboratory / Duke University Phytotron are currently researching the dynamical responses of plants to environmental changes forecasted from increasing greenhouse trace gases involved in global change. The biological research primary focus is to investigate the impact of elevated atmospheric CO2 and nutrients limitation on carbon and nitrogen dynamics in plants. We report here on preliminary results of 11CO2 plant imaging experiments involving barley plants using Jefferson Lab dual planar positron emission tomography detectors to image 11CO2 in live barley plants. New detector designs will be developed based on the preliminary studies reported here and further planned.

  18. The methodology of TSPO imaging with positron emission tomography.

    PubMed

    Turkheimer, Federico E; Rizzo, Gaia; Bloomfield, Peter S; Howes, Oliver; Zanotti-Fregonara, Paolo; Bertoldo, Alessandra; Veronese, Mattia

    2015-08-01

    The 18-kDA translocator protein (TSPO) is consistently elevated in activated microglia of the central nervous system (CNS) in response to a variety of insults as well as neurodegenerative and psychiatric conditions. It is therefore a target of interest for molecular strategies aimed at imaging neuroinflammation in vivo. For more than 20 years, positron emission tomography (PET) has allowed the imaging of TSPO density in brain using [(11)C]-(R)-PK11195, a radiolabelled-specific antagonist of the TSPO that has demonstrated microglial activation in a large number pathological cohorts. The significant clinical interest in brain immunity as a primary or comorbid factor in illness has sparked great interest in the TSPO as a biomarker and a surprising number of second generation TSPO radiotracers have been developed aimed at improving the quality of TSPO imaging through novel radioligands with higher affinity. However, such major investment has not yet resulted in the expected improvement in image quality. We here review the main methodological aspects of TSPO PET imaging with particular attention to TSPO genetics, cellular heterogeneity of TSPO in brain tissue and TSPO distribution in blood and plasma that need to be considered in the quantification of PET data to avoid spurious results as well as ineffective development and use of these radiotracers.

  19. Simultaneous laser speckle imaging and positron emission tomography

    NASA Astrophysics Data System (ADS)

    Gramer, M.; Feuerstein, D.; Backes, H.; Takagaki, M.; Kumagai, T.; Graf, R.

    2013-06-01

    Complex biological systems often require measurements of multiple parameters with high temporal and spatial resolution. Multimodal approaches and the combination of methods are therefore a powerful tool to address such scientific questions. Laser speckle imaging (LSI) is an optical method that monitors dynamic changes in cortical blood flow (CBF) with high temporal resolution. Positron emission tomography (PET) allows for quantitative imaging of physiological processes and is a gold standard method to determine absolute cerebral blood flow. We developed a setup that allows simultaneous measurement with both modalities. Here, we simultaneously measured CBF with PET and LSI in rats and analyzed how the correlation of PET and LSI is modified when (1) different methods are used for the calculation of speckle inverse correlation time (ICT), (2) speckle data is acquired through thinned or craniectomized skull, (3) influence of surface vessels is removed from the speckle data. For the latter, a method for automated vessel segmentation from LSI data was developed. We obtained the best correlation (R² = 0.890, p<0.001) when correcting for surface vessel structures taking into account the contribution of static scatterers while keeping the coherence factor constant. However, using the originally published relation, which allows a 900 times faster computation of blood flow maps, still provided a good correlation (R2 = 0.879, p<0.001). Given the good correlation between LSI and PET we used our data to calibrate the speckle ICT. Thus, LSI provides CBF in absolute units at high temporal resolution.

  20. Quantifying the limitations of small animal positron emission tomography

    NASA Astrophysics Data System (ADS)

    Oxley, D. C.; Boston, A. J.; Boston, H. C.; Cooper, R. J.; Cresswell, J. R.; Grint, A. N.; Nolan, P. J.; Scraggs, D. P.; Lazarus, I. H.; Beveridge, T. E.

    2009-06-01

    The application of position sensitive semiconductor detectors in medical imaging is a field of global research interest. The Monte-Carlo simulation toolkit GEANT4 [ http://geant4.web.cern.ch/geant4/] was employed to improve the understanding of detailed γ-ray interactions within the small animal Positron Emission Tomography (PET), high-purity germanium (HPGe) imaging system, SmartPET [A.J. Boston, et al., Oral contribution, ANL, Chicago, USA, 2006]. This system has shown promising results in the field of PET [R.J. Cooper, et al., Nucl. Instr. and Meth. A (2009), accepted for publication] and Compton camera imaging [J.E. Gillam, et al., Nucl. Instr. and Meth. A 579 (2007) 76]. Images for a selection of single and multiple point, line and phantom sources were successfully reconstructed using both a filtered-back-projection (FBP) [A.R. Mather, Ph.D. Thesis, University of Liverpool, 2007] and an iterative reconstruction algorithm [A.R. Mather, Ph.D. Thesis, University of Liverpool, 2007]. Simulated data were exploited as an alternative route to a reconstructed image allowing full quantification of the image distortions introduced in each phase of the data processing. Quantifying the contribution of uncertainty in all system components from detector to reconstruction algorithm allows the areas in need of most attention on the SmartPET project and semiconductor PET to be addressed.

  1. Microfluidics for Positron Emission Tomography (PET) Imaging Probe Development

    PubMed Central

    Wang, Ming-Wei; Lin, Wei-Yu; Liu, Kan; Masterman-Smith, Michael; Shen, Clifton Kwang-Fu

    2012-01-01

    Due to increased needs for Positron Emission Tomography (PET) scanning, high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidic-based radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates and easier purification processes with greater yield and higher specific activity of desired probes. Several ‘proof-of-principle’ examples, along with basics of device architecture and operation, and potential limitations of each design are discussed here. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories (“decentralized model”), an easy-to-use, standalone, flexible, fully-automated radiochemical microfluidic platform can open up to simpler and more cost-effective procedures for molecular imaging using PET. PMID:20643021

  2. Automated identification of the lung contours in positron emission tomography

    NASA Astrophysics Data System (ADS)

    Nery, F.; Silvestre Silva, J.; Ferreira, N. C.; Caramelo, F. J.; Faustino, R.

    2013-03-01

    Positron Emission Tomography (PET) is a nuclear medicine imaging technique that permits to analyze, in three dimensions, the physiological processes in vivo. One of the areas where PET has demonstrated its advantages is in the staging of lung cancer, where it offers better sensitivity and specificity than other techniques such as CT. On the other hand, accurate segmentation, an important procedure for Computer Aided Diagnostics (CAD) and automated image analysis, is a challenging task given the low spatial resolution and the high noise that are intrinsic characteristics of PET images. This work presents an algorithm for the segmentation of lungs in PET images, to be used in CAD and group analysis in a large patient database. The lung boundaries are automatically extracted from a PET volume through the application of a marker-driven watershed segmentation procedure which is robust to the noise. In order to test the effectiveness of the proposed method, we compared the segmentation results in several slices using our approach with the results obtained from manual delineation. The manual delineation was performed by nuclear medicine physicians that used a software routine that we developed specifically for this task. To quantify the similarity between the contours obtained from the two methods, we used figures of merit based on region and also on contour definitions. Results show that the performance of the algorithm was similar to the performance of human physicians. Additionally, we found that the algorithm-physician agreement is similar (statistically significant) to the inter-physician agreement.

  3. The use of fluorine-18 fluorodeoxyglucose positron emission tomography for imaging human motor neuronal activation in the brain

    PubMed Central

    PAHK, KISOO; PARK, KUN-WOO; PYUN, SUNG BOM; LEE, JAE SUNG; KIM, SUNGEUN; CHOE, JAE GOL

    2015-01-01

    The present study aimed to visualize human motor neuronal activation in the brain using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET), and to develop an FDG-PET procedure for imaging neuronal activation. A male volunteer underwent 20 min periods of rest and motor activation, whilst being assessed using FDG-PET on two consecutive days. The motor task, which involved repetitively grasping and releasing the right hand, was performed during the initial 5 min of the activation period. Subtraction of the rest period signal from the activation PET images was performed using the subtraction ictal single-photon emission computed tomography co-registered to magnetic resonance imaging method. The subtracted image detected activation of the contralateral (left) primary motor cortex, supplementary motor area, and ipsilateral (right) cerebellum. In the present study, FDG-PET detected significantly increased motor-associated activation of the brain in a subject performing a motor task. PMID:26668604

  4. Fingerprint fake detection by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Meissner, Sven; Breithaupt, Ralph; Koch, Edmund

    2013-03-01

    The most established technique for the identification at biometric access control systems is the human fingerprint. While every human fingerprint is unique, fingerprints can be faked very easily by using thin layer fakes. Because commercial fingerprint scanners use only a two-dimensional image acquisition of the finger surface, they can only hardly differentiate between real fingerprints and fingerprint fakes applied on thin layer materials. A Swept Source OCT system with an A-line rate of 20 kHz and a lateral and axial resolution of approximately 13 μm, a centre wavelength of 1320 nm and a band width of 120 nm (FWHM) was used to acquire fingerprints and finger tips with overlying fakes. Three-dimensional volume stacks with dimensions of 4.5 mm x 4 mm x 2 mm were acquired. The layering arrangement of the imaged finger tips and faked finger tips was analyzed and subsequently classified into real and faked fingerprints. Additionally, sweat gland ducts were detected and consulted for the classification. The manual classification between real fingerprints and faked fingerprints results in almost 100 % correctness. The outer as well as the internal fingerprint can be recognized in all real human fingers, whereby this was not possible in the image stacks of the faked fingerprints. Furthermore, in all image stacks of real human fingers the sweat gland ducts were detected. The number of sweat gland ducts differs between the test persons. The typical helix shape of the ducts was observed. In contrast, in images of faked fingerprints we observe abnormal layer arrangements and no sweat gland ducts connecting the papillae of the outer fingerprint and the internal fingerprint. We demonstrated that OCT is a very useful tool to enhance the performance of biometric control systems concerning attacks by thin layer fingerprint fakes.

  5. Assessment of patient selection criteria for quantitative imaging with respiratory-gated positron emission tomography.

    PubMed

    Bowen, Stephen R; Pierce, Larry A; Alessio, Adam M; Liu, Chi; Wollenweber, Scott D; Stearns, Charles W; Kinahan, Paul E

    2014-07-01

    The objective of this investigation was to propose techniques for determining which patients are likely to benefit from quantitative respiratory-gated imaging by correlating respiratory patterns to changes in positron emission tomography (PET) metrics. Twenty-six lung and liver cancer patients underwent PET/computed tomography exams with recorded chest/abdominal displacements. Static and adaptive amplitude-gated [[Formula: see text

  6. RF Tomography for Tunnel Detection: Principles and Inversion Schemes

    NASA Astrophysics Data System (ADS)

    Lo Monte, L.; Erricolo, D.; Inan, U. S.; Wicks, M. C.

    2008-12-01

    We propose a novel way to detect underground tunnels based on classical seismic tomography, Ground Penetrating Radar (GPR), inverse scattering principles, and the deployment of distributed sensors, which we call "Distributed RF Tomography". Tunnel detection has been a critical problem that cannot be considered fully solved. Presently, tunnel detection is performed by methods that include seismic sensors, electrical impedance, microgravity, boreholes, and GPR. All of these methods have drawbacks that make them not applicable for use in unfriendly environments, such as battlefields. Specifically, they do not cover wide surface areas, they are generally shallow, they are limited to vertical prospecting, and require the user to be in situ, which may jeopardize one's safety. Additional application of the proposed distributed RF tomography include monitoring sensitive areas, (e.g. banks, power plants, military bases, prisons, national borders) and civil applications (e.g. environmental engineering, mine safety, search and rescue, speleology, archaeology and geophysics). The novelty of a Distributed RF tomography system consists of the following. 1) Sensors are scattered randomly above the ground, thus saving time and money compared to the use of boreholes. 2) The use of lower operating frequency (around HF), which allows for deeper penetration. 3) The use of CW diffraction tomography, which increases the resolution to sub-wavelength values, independently from the sensor displacement, and increases the SNR. 4) Use of linear inversion schemes that are suited for tunnel detection. 5) The use of modulation schemes and signal processing algorithms to mitigate interferences and noise. This presentation will cover: 1. Current physical limits of existing techniques for tunnel detection. 2. Concept of Distributed RF Tomography. 3. Inversion theories and strategies a. Proper forward model for voids buried into an homogeneous medium b. Extended matched filtering inversion c. Near

  7. 77 FR 71802 - Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... HUMAN SERVICES Food and Drug Administration Guidance on Investigational New Drug Applications for... ``Investigational New Drug Applications for Positron Emission Tomography (PET) Drugs.'' The guidance is intended to assist manufacturers of PET drugs in submitting investigational new drug applications (INDs)....

  8. Prediction of positron emission tomography/computed tomography (PET/CT) positivity in patients with high-risk primary melanoma

    PubMed Central

    Danielsen, Maria; Kjaer, Andreas; Wu, Max; Martineau, Lea; Nosrati, Mehdi; Leong, Stanley PL; Sagebiel, Richard W; III, James R Miller; Kashani-Sabet, Mohammed

    2016-01-01

    Positron emission tomography/computed tomography (PET/CT) is an important tool to identify occult melanoma metastasis. To date, it is controversial which patients with primary cutaneous melanoma should have staging PET/CT. In this retrospective analysis of more than 800 consecutive patients with cutaneous melanoma, we sought to identify factors predictive of PET/CT positivity in the setting of newly-diagnosed high-risk primary melanoma to determine those patients most appropriate to undergo a PET/CT scan as part of their diagnostic work up. 167 patients with newly-diagnosed high-risk primary cutaneous melanoma underwent a PET/CT scan performed as part of their initial staging. Clinical and histologic factors were evaluated as possible predictors of melanoma metastasis identified on PET/CT scanning using both univariate and multivariate logistic regression. In all, 32 patients (19.2%) had a positive PET/CT finding of metastatic melanoma. In more than half of these patients (56.3%), PET/CT scanning identified disease that was not detectable on clinical examination. Mitotic rate, tumor thickness, lymphadenopathy, and bleeding were significantly predictive of PET/CT positivity. A combinatorial index constructed from these factors revealed a significant association between number of high-risk factors observed and prevalence of PET/CT positivity, which increased from 5.8% (with the presence of 0-2 factors) to 100.0%, when all four factors were present. These results indicate that combining clinical and histologic prognostic factors enables the identification of patients with a higher likelihood of a positive PET/CT scan. PMID:27766186

  9. Clinical positron emission tomography/magnetic resonance imaging applications.

    PubMed

    von Schulthess, Gustav K; Kuhn, Felix Pierre; Kaufmann, Philipp; Veit-Haibach, Patrick

    2013-01-01

    Although clinical positron emission tomography (PET)/computed tomography (CT) applications were obvious and have completely replaced PET in oncology, clinical applications of PET/magnetic resonance (MR) are currently not clearly defined. This is due to the lack of clinical data, which is mainly because PET/MR technology is not clinically mature at this point. Open issues are technical and concern ease of obtaining PET attenuation correction maps, dealing with, for example, MR surface coil metal in the PET field-of-view and appropriate workflows leading to a cost-effective examination. All issues can be circumvented by using a shuttle-connected PET/CT-MR system, but the penalty is that simultaneous PET and MR imaging are not possible and potential motion between examinations may occur. Clinically, some systems installed worldwide start to have a reasonable bulk of clinical data. Preliminary results suggest that in oncology, PET/MR may have advantages over PET/CT in head and neck imaging. In liver imaging, more PET-positive lesions are seen on MR than on CT, but that does not mean that PET/MR is superior to PET/CT. Possibly in some settings where a contrast-enhanced PET/CT is needed to be diagnostic, PET/MR can be done without contrast media. Although PET/CT has virtually no role in brain imaging, this may be an important domain for PET/MR, particularly in dementia imaging. The role of PET/MR in the heart is as yet undefined, and much research will have to be done to elucidate this role. At this point, it is also not clear where the simultaneity afforded by a fully integrated PET/MR is really needed. Sequential data acquisition even on separate systems and consecutive software image fusion may well be appropriate. With the increasing installed base of systems, clinical data will be forthcoming and define more clearly where there is clinical value in PET/MR at an affordable price. PMID:23178084

  10. Clinical Utility of Thallium-201 Single Photon Emission Computed Tomography and Cerebrospinal Fluid Epstein-Barr Virus Detection Using Polymerase Chain Reaction in the Diagnosis of AIDS-Related Primary Central Nervous System Lymphoma

    PubMed Central

    Hussain, Fadilah S

    2016-01-01

    Objective: To determine the diagnostic efficiency of thallium-201 single photon emission computed tomography (SPECT) and Epstein-Barr virus (EBV) polymerase chain reaction (PCR) in the differentiation of primary central nervous system lymphoma (PCNSL) from other central nervous system processes in patients with HIV/AIDS. Design/Methods: Over 10 years, 68 thallium-201 SPECT scans were performed on neurologically symptomatic HIV+ patients with focal lesions on CT or MRI at the Johns Hopkins Hospital. Diagnoses were then established by either autopsy, biopsy, or clinical response to anti-toxoplasmosis therapy. Patients were categorized prior to a prospective clinical reading of the SPECT scans by nuclear medicine physicians. Results: In our patient sample overall, the diagnostic efficiency of thallium-201 SPECT was 79%. The diagnostic accuracy of EBV PCR testing alone in a subset of 22 patients in our study that had CSF analyzed was 73%. However, when both positive EBV PCR and positive thallium-201 SPECT results were used together, the diagnostic accuracy improved to 100% based on a sample of 13 patients where EBV PCR and SPECT imaging results were concordant.  Conclusion: Thallium-201 SPECT has a relatively high positive predictive value with regards to the diagnosis of PCNSL, which suggests that patients with positive results could undergo empiric radiation treatment without resorting to brain biopsy. However, the predictive value can be increased by testing for CSF EBV using PCR. Alternatively, if CSF cannot be safely obtained because of mass effect, we believe that these data still suggest that empiric radiation treatment should be considered when discussing treatment options with patients with a positive thallium-201 SPECT. PMID:27330874

  11. Detecting small scale CO2 emission structures using OCO-2

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Eldering, Annmarie; Verhulst, Kristal R.; Miller, Charles E.; Nguyen, Hai M.; Oda, Tomohiro; O'Dell, Christopher; Rao, Preeti; Kahn, Brian; Crisp, David; Gunson, Michael R.; Sanchez, Robert M.; Ashok, Manasa; Pieri, David; Linick, Justin P.; Yuen, Karen

    2016-04-01

    Localized carbon dioxide (CO2) emission structures cover spatial domains of less than 50 km diameter and include cities and transportation networks, as well as fossil fuel production, upgrading and distribution infra-structure. Anthropogenic sources increasingly upset the natural balance between natural carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. NASA's first satellite dedicated to atmospheric CO2 observation, the July 2014 launched Orbiting Carbon Observatory (OCO-2), now leads the afternoon constellation of satellites (A-Train). Its continuous swath of 2 to 10 km in width and eight footprints across can slice through coincident emission plumes and may provide momentary cross sections. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban total column averaged CO2 enhancements of ~2 ppm against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban spatial structures reflected in XCO2 data, previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban tomography of greenhouse gases. For singular point sources like coal fired power plants, we have developed proxy detections of plumes using bands of imaging spectrometers with sensitivity to SO2 in the thermal infrared (ASTER). This approach provides a means to automate plume detection with subsequent matching and mining of OCO-2 data for enhanced detection efficiency and validation. © California Institute of Technology

  12. Budget impact from the incorporation of positron emission tomography – computed tomography for staging lung cancers

    PubMed Central

    Biz, Aline Navega; Caetano, Rosângela

    2015-01-01

    OBJECTIVE To estimate the budget impact from the incorporation of positron emission tomography (PET) in mediastinal and distant staging of non-small cell lung cancer. METHODS The estimates were calculated by the epidemiological method for years 2014 to 2018. Nation-wide data were used about the incidence; data on distribution of the disease´s prevalence and on the technologies’ accuracy were from the literature; data regarding involved costs were taken from a micro-costing study and from Brazilian Unified Health System (SUS) database. Two strategies for using PET were analyzed: the offer to all newly-diagnosed patients, and the restricted offer to the ones who had negative results in previous computed tomography (CT) exams. Univariate and extreme scenarios sensitivity analyses were conducted to evaluate the influence from sources of uncertainties in the parameters used. RESULTS The incorporation of PET-CT in SUS would imply the need for additional resources of 158.1 BRL (98.2 USD) million for the restricted offer and 202.7 BRL (125.9 USD) million for the inclusive offer in five years, with a difference of 44.6 BRL (27.7 USD) million between the two offer strategies within that period. In absolute terms, the total budget impact from its incorporation in SUS, in five years, would be 555 BRL (345 USD) and 600 BRL (372.8 USD) million, respectively. The costs from the PET-CT procedure were the most influential parameter in the results. In the most optimistic scenario, the additional budget impact would be reduced to 86.9 BRL (54 USD) and 103.8 BRL (64.5 USD) million, considering PET-CT for negative CT and PET-CT for all, respectively. CONCLUSIONS The incorporation of PET in the clinical staging of non-small cell lung cancer seems to be financially feasible considering the high budget of the Brazilian Ministry of Health. The potential reduction in the number of unnecessary surgeries may cause the available resources to be more efficiently allocated. PMID:26274871

  13. Positron emission tomography: a first-hand experience.

    PubMed

    Traylor, J

    2000-01-01

    In July 1999, the University of Kansas Hospital installed a positron emission tomography (PET) scanner and added PET to the imaging technologies it offers patients and physicians. The new service is managed by the nuclear medicine section in the department of radiology. Plans are being implemented now to install a cyclotron in March 2000. Prior to installation of the scanner, a radiation area survey was performed in the space being considered for the PET unit. We also needed to address other critical considerations, including the manufacturer's requirements for construction of the scanner room, special electrical needs, and how the system would connect to our existing information network. It is important to work closely with your chief financial officer and chief operations officer from the beginning of the purchasing process so that these administrators have up-to-date, supportive information about PET and the progress of the installation. We made use of a variety of promotional techniques to market the new service, including broadcast e-mail, an open house for potential referring physicians, postings on the nuclear medicine Web site and communication through the local media. We also worked with the major insurance providers that utilize our hospital to educate them about PET and its benefits. In addition, we trained our own billing staff about procedures that optimize reimbursement for PET. In March 2000, University of Kansas Hospital will install the first cyclotron in the state, enabling us to generate the drugs used for PET scanning and potentially to add targets for research PET radiopharmaceuticals. PMID:10787761

  14. PDE regularization for Bayesian reconstruction of emission tomography

    NASA Astrophysics Data System (ADS)

    Wang, Zhentian; Zhang, Li; Xing, Yuxiang; Zhao, Ziran

    2008-03-01

    The aim of the present study is to investigate a type of Bayesian reconstruction which utilizes partial differential equations (PDE) image models as regularization. PDE image models are widely used in image restoration and segmentation. In a PDE model, the image can be viewed as the solution of an evolutionary differential equation. The variation of the image can be regard as a descent of an energy function, which entitles us to use PDE models in Bayesian reconstruction. In this paper, two PDE models called anisotropic diffusion are studied. Both of them have the characteristics of edge-preserving and denoising like the popular median root prior (MRP). We use PDE regularization with an Ordered Subsets accelerated Bayesian one step late (OSL) reconstruction algorithm for emission tomography. The OS accelerated OSL algorithm is more practical than a non-accelerated one. The proposed algorithm is called OSEM-PDE. We validated the OSEM-PDE using a Zubal phantom in numerical experiments with attenuation correction and quantum noise considered, and the results are compared with OSEM and an OS version of MRP (OSEM-MRP) reconstruction. OSEM-PDE shows better results both in bias and variance. The reconstruction images are smoother and have sharper edges, thus are more applicable for post processing such as segmentation. We validate this using a k-means segmentation algorithm. The classic OSEM is not convergent especially in noisy condition. However, in our experiment, OSEM-PDE can benefit from OS acceleration and keep stable and convergent while OSEM-MRP failed to converge.

  15. Muscle use during double poling evaluated by positron emission tomography.

    PubMed

    Bojsen-Møller, Jens; Losnegard, Thomas; Kemppainen, Jukka; Viljanen, Tapio; Kalliokoski, Kari K; Hallén, Jostein

    2010-12-01

    Due to the complexity of movement in cross-country skiing (XCS), the muscle activation patterns are not well elucidated. Previous studies have applied surface electromyography (SEMG); however, recent gains in three-dimensional (3D) imaging techniques such as positron emission tomography (PET) have rendered an alternative approach to investigate muscle activation. The purpose of the present study was to examine muscle use during double poling (DP) at two work intensities by use of PET. Eight male subjects performed two 20-min DP bouts on separate days. Work intensity was ∼ 53 and 74% of peak oxygen uptake (Vo(2peak)), respectively. During exercise 188 ± 8 MBq of [(18)F]fluorodeoxyglucose ([(18)F]FDG) was injected, and subsequent to exercise a full-body PET scan was conducted. Regions of interest (ROI) were defined within 15 relevant muscles, and a glucose uptake index (GUI) was determined for all ROIs. The muscles that span the shoulder and elbow joints, the abdominal muscles, and hip flexors displayed the greatest GUI during DP. Glucose uptake did not increase significantly from low to high intensity in most upper body muscles; however, an increased GUI (P < 0.05) was seen for the knee flexor (27%) and extensor muscles (16%), and for abdominal muscles (21%). The present data confirm previous findings that muscles of the upper limb are the primary working muscles in DP. The present data further suggest that when exercise intensity increases, the muscles that span the lumbar spine, hip, and knee joints contribute increasingly. Finally, PET provides a promising alternative or supplement to existing methods to assess muscle activation in complex human movements.

  16. High-resolution PET (positron emission tomography) for medical science studies

    SciTech Connect

    Budinger, T.F.; Derenzo, S.E.; Huesman, R.H.; Jagust, W.J.; Valk, P.E. )

    1989-09-01

    One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging. 6 refs., 21 figs.

  17. High-resolution PET [Positron Emission Tomography] for Medical Science Studies

    DOE R&D Accomplishments Database

    Budinger, T. F.; Derenzo, S. E.; Huesman, R. H.; Jagust, W. J.; Valk, P. E.

    1989-09-01

    One of the unexpected fruits of basic physics research and the computer revolution is the noninvasive imaging power available to today's physician. Technologies that were strictly the province of research scientists only a decade or two ago now serve as the foundations for such standard diagnostic tools as x-ray computer tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), ultrasound, single photon emission computed tomography (SPECT), and positron emission tomography (PET). Furthermore, prompted by the needs of both the practicing physician and the clinical researcher, efforts to improve these technologies continue. This booklet endeavors to describe the advantages of achieving high resolution in PET imaging.

  18. Spectrum of fluorodeoxyglucose-positron emission tomography/computed tomography and magnetic resonance imaging findings of ovarian tumors.

    PubMed

    Kitajima, Kazuhiro; Ueno, Yoshiko; Maeda, Tetsuo; Murakami, Koji; Kaji, Yasushi; Kita, Masato; Suzuki, Kayo; Sugimura, Kazuro

    2011-11-01

    The purpose of this article is to review fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) findings in a variety of benign, malignant, and borderline malignant ovarian tumors. It is advantageous to become familiar with the wide variety of FDG-PET/CT findings of this entity. Benign ovarian tumors generally have faint uptake, whereas endometriomas, fibromas, and teratomas show mild to moderate uptake. Malignant ovarian tumors generally have intense uptake, whereas tumors with a small solid component often show minimal uptake.

  19. Metastatic superscan in prostate carcinoma on gallium-68-prostate-specific membrane antigen positron emission tomography/computed tomography scan

    PubMed Central

    Agarwal, Krishan Kant; Tripathi, Madhavi; Kumar, Rajeev; Bal, Chandrasekhar

    2016-01-01

    We describe the imaging features of a metastatic superscan on gallium-68 Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as gallium-68-prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging. 68Ga-PSMA is novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. This patient had a superscan of metastases on conventional bone scintigraphy and was referred for 68Ga-PSMA PET/CT to evaluate the feasibility of 177Lu-PSMA therapy. PMID:27095868

  20. Clinical usefulness of post-operative 18F-fluorodeoxyglucose positron emission tomography-computed tomography in canine hemangiosarcoma

    PubMed Central

    Lee, Gahyun; Kwon, Seong Young; Son, Kyuyeol; Park, Seungjo; Lee, Ju-hwan; Cho, Kyoung-Oh; Min, Jung-Joon

    2016-01-01

    This report describes the usefulness of positron emission tomography-computed tomography (PET-CT) for evaluating recurrent or residual tumors following surgery. CT and 18F-fluorodeoxyglucose PET-CT were pre- and post-operatively applied to multiple masses in a dog with hemangiosarcoma. The distinction between the left subcutaneous mass and the peritoneum was clarified on pre-operative CT examination, and malignancy was suspected based on PET-CT. A recurrent or residual tumor in the left subcutaneous region was suspected on post-operative PET-CT, and confirmed through histopathologic examination. PMID:26645332

  1. Clinical Utility of Positron Emission Tomography Magnetic Resonance Imaging (PET-MRI) in Gastrointestinal Cancers

    PubMed Central

    Matthews, Robert; Choi, Minsig

    2016-01-01

    Anatomic imaging utilizing both CT (computed tomography) and MRI (magnetic resonance imaging) limits the assessment of cancer metastases in lymph nodes and distant organs while functional imaging like PET (positron emission tomography) scan has its limitation in spatial resolution capacity. Hybrid imaging utilizing PET-CT and PET-MRI are novel imaging modalities that are changing the current landscape in cancer diagnosis, staging, and treatment response. MRI has shown to have higher sensitivity in soft tissue, head and neck pathology, and pelvic disease, as well as, detecting small metastases in the liver and bone compared to CT. Combining MRI with PET allows for detection of metastases that may have been missed with current imaging modalities. In this review, we will examine the clinical utility of FDG PET-MRI in the diagnosis and staging of gastrointestinal cancers with focus on esophageal, stomach, colorectal, and pancreatic cancers. We will also explore its role in treatment response and future directions associated with it. PMID:27618106

  2. Imaging Prostate Cancer: An Update on Positron Emission Tomography and Magnetic Resonance Imaging

    PubMed Central

    Turkbey, Baris; Choyke, Peter; Capala, Jacek

    2012-01-01

    Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an essential role in the clinical management of patients. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI allows functional assessment with techniques such as diffusion-weighted MRI, MR spectroscopy, and dynamic contrast-enhanced MRI. The most common PET radiotracer, 18F-fluorodeoxyglucose, is not very useful in prostate cancer. However, in recent years other PET tracers have improved the accuracy of PET/CT imaging of prostate cancer. Among these, choline (labeled with 18F or 11C), 11C-acetate, and 18F-fluoride have demonstrated promising results, and other new radiopharmaceuticals are currently under evaluation in preclinical and clinical studies. PMID:20425625

  3. Clinical Utility of Positron Emission Tomography Magnetic Resonance Imaging (PET-MRI) in Gastrointestinal Cancers.

    PubMed

    Matthews, Robert; Choi, Minsig

    2016-01-01

    Anatomic imaging utilizing both CT (computed tomography) and MRI (magnetic resonance imaging) limits the assessment of cancer metastases in lymph nodes and distant organs while functional imaging like PET (positron emission tomography) scan has its limitation in spatial resolution capacity. Hybrid imaging utilizing PET-CT and PET-MRI are novel imaging modalities that are changing the current landscape in cancer diagnosis, staging, and treatment response. MRI has shown to have higher sensitivity in soft tissue, head and neck pathology, and pelvic disease, as well as, detecting small metastases in the liver and bone compared to CT. Combining MRI with PET allows for detection of metastases that may have been missed with current imaging modalities. In this review, we will examine the clinical utility of FDG PET-MRI in the diagnosis and staging of gastrointestinal cancers with focus on esophageal, stomach, colorectal, and pancreatic cancers. We will also explore its role in treatment response and future directions associated with it. PMID:27618106

  4. Automated choroidal neovascularization detection algorithm for optical coherence tomography angiography

    PubMed Central

    Liu, Li; Gao, Simon S.; Bailey, Steven T.; Huang, David; Li, Dengwang; Jia, Yali

    2015-01-01

    Optical coherence tomography angiography has recently been used to visualize choroidal neovascularization (CNV) in participants with age-related macular degeneration. Identification and quantification of CNV area is important clinically for disease assessment. An automated algorithm for CNV area detection is presented in this article. It relies on denoising and a saliency detection model to overcome issues such as projection artifacts and the heterogeneity of CNV. Qualitative and quantitative evaluations were performed on scans of 7 participants. Results from the algorithm agreed well with manual delineation of CNV area. PMID:26417524

  5. When to perform positron emission tomography/computed tomography or radionuclide bone scan in patients with recently diagnosed prostate cancer.

    PubMed

    Caldarella, Carmelo; Treglia, Giorgio; Giordano, Alessandro; Giovanella, Luca

    2013-01-01

    Skeletal metastases are very common in prostate cancer and represent the main metastatic site in about 80% of prostate cancer patients, with a significant impact in patients' prognosis. Early detection of bone metastases is critical in the management of patients with recently diagnosed high-risk prostate cancer: radical treatment is recommended in case of localized disease; systemic therapy should be preferred in patients with distant secondary disease. Bone scintigraphy using radiolabeled bisphosphonates is of great importance in the management of these patients; however, its main drawback is its low overall accuracy, due to the nonspecific uptake in sites of increased bone turnover. Positron-emitting radiopharmaceuticals, such as fluorine-18-fluorodeoxyglucose, choline-derived drugs (fluorine-18-fluorocholine and carbon-11-choline) and sodium fluorine-18-fluoride, are increasingly used in clinical practice to detect metastatic spread, and particularly bone involvement, in patients with prostate cancer, to reinforce or substitute information provided by bone scan. Each radiopharmaceutical has a specific mechanism of uptake; therefore, diagnostic performances may differ from one radiopharmaceutical to another on the same lesions, as demonstrated in the literature, with variable sensitivity, specificity, and overall accuracy values in the same patients. Whether bone scintigraphy can be substituted by these new methods is a matter of debate. However, greater radiobiological burden, higher costs, and the necessity of an in-site cyclotron limit the use of these positron emission tomography methods as first-line investigations in patients with prostate cancer: bone scintigraphy remains the mainstay for the detection of bone metastases in current clinical practice. PMID:23861598

  6. 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.

  7. Enhancement of molecular sensitivity in positron emission tomography with quantum correlation of γ-ray photons

    SciTech Connect

    Sato, K.; Kobayashi, Y.

    2015-05-15

    Enhancement of molecular sensitivity in positron emission tomography (PET) has long been discussed with respect to imaging instrumentation and algorithms for data treatment. Here, the molecular sensitivity in PET is discussed on the basis of 2-dimensional coincident measurements of 511 keV γ ray photons resultant from two-photon annihilation. Introduction of an additional selection window based on the energy sum and difference of the coincidently measured γ ray photons, without any significant instrumental and algorithmic changes, showed an improvement in the signal-to-noise ratio (SNR) by an order of magnitude. Improvement of performance characteristics in the PET imaging system was demonstrated by an increase in the noise equivalent count rate (NECR) which takes both the SNR and the detection efficiency into consideration. A further improvement of both the SNR and the NECR is expected for the present system in real clinical and in-vivo environments, where much stronger positron sources are employed.

  8. Enhancement of molecular sensitivity in positron emission tomography with quantum correlation of γ-ray photons.

    PubMed

    Sato, K; Kobayashi, Y

    2015-05-01

    Enhancement of molecular sensitivity in positron emission tomography (PET) has long been discussed with respect to imaging instrumentation and algorithms for data treatment. Here, the molecular sensitivity in PET is discussed on the basis of 2-dimensional coincident measurements of 511 keV γ ray photons resultant from two-photon annihilation. Introduction of an additional selection window based on the energy sum and difference of the coincidently measured γ ray photons, without any significant instrumental and algorithmic changes, showed an improvement in the signal-to-noise ratio (SNR) by an order of magnitude. Improvement of performance characteristics in the PET imaging system was demonstrated by an increase in the noise equivalent count rate (NECR) which takes both the SNR and the detection efficiency into consideration. A further improvement of both the SNR and the NECR is expected for the present system in real clinical and in-vivo environments, where much stronger positron sources are employed.

  9. Clinical use of amyloid-positron emission tomography neuroimaging: Practical and bioethical considerations.

    PubMed

    Witte, Michael M; Foster, Norman L; Fleisher, Adam S; Williams, Monique M; Quaid, Kimberly; Wasserman, Michael; Hunt, Gail; Roberts, J Scott; Rabinovici, Gil D; Levenson, James L; Hake, Ann Marie; Hunter, Craig A; Van Campen, Luann E; Pontecorvo, Michael J; Hochstetler, Helen M; Tabas, Linda B; Trzepacz, Paula T

    2015-09-01

    Until recently, estimation of β-amyloid plaque density as a key element for identifying Alzheimer's disease (AD) pathology as the cause of cognitive impairment was only possible at autopsy. Now with amyloid-positron emission tomography (amyloid-PET) neuroimaging, this AD hallmark can be detected antemortem. Practitioners and patients need to better understand potential diagnostic benefits and limitations of amyloid-PET and the complex practical, ethical, and social implications surrounding this new technology. To complement the practical considerations, Eli Lilly and Company sponsored a Bioethics Advisory Board to discuss ethical issues that might arise from clinical use of amyloid-PET neuroimaging with patients being evaluated for causes of cognitive decline. To best address the multifaceted issues associated with amyloid-PET neuroimaging, we recommend this technology be used only by experienced imaging and treating physicians in appropriately selected patients and only in the context of a comprehensive clinical evaluation with adequate explanations before and after the scan. PMID:27239516

  10. Detection of Foreign Bodies by Spiral Computed Tomography and Cone Beam Computed Tomography in Maxillofacial Regions

    PubMed Central

    Kaviani, Farzaneh; Javad Rashid, Reza; Shahmoradi, Zahra; Gholamian, Masoud

    2014-01-01

    Background and aims. The imaging techniques commonly used for foreign body detection include plain radiography, xeroradiography, computed tomography (CT) scans, magnetic resonance imaging (MRI) and ultrasonography. The aim of the present study was to compare cone-beam computed tomography (CBCT) with conventional CT scan in determination of the exact location of a foreign body in the maxillofacial area in vitro. Materials and methods. In this descriptive study, seven different materials were selected as foreign bodies with dimensions of approximately 2 mm, 1 mm, and 0.5 mm. These materials consisted of metal, glass, wood, stone, plastic, graphite and tooth. These foreign bodies were placed in a sheep head between the corpus of the mandible and muscle, in the tongue and in an air space. One conventional CT scan and two CBCT scans were made on the models. Results. Tooth, metal, stone and glass foreign bodies were seen clearly on CT and CBCT scans made by NewTom at the smallest size in air. However, CBCT scan by NewTom was a more effective technique for visualization of foreign bodies in air compared to conventional CT. Foreign bodies measuring 0.5 mm made of metal, stone, glass, graphite and teeth were detected by all devices in muscle tissue and adjacent bone. Conclusion. According to the results, CBCT scans of NewTom and Planmeca are appropriate tools for detecting foreign bodies with relative high density in the maxillofacial area. PMID:25346836

  11. Computed tomography and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography findings in adrenal candidiasis and histoplasmosis: two cases.

    PubMed

    Altinmakas, Emre; Guo, Ming; Kundu, Uma R; Habra, Mouhammed Amir; Ng, Chaan

    2015-01-01

    We report the contrast-enhanced computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography findings in adrenal histoplasmosis and candidiasis. Both demonstrated bilateral hypermetabolic heterogeneous adrenal masses with limited wash-out on delayed CT. Adrenal candidiasis has not been previously reported, nor have the CT wash-out findings in either infection. The adrenal imaging findings are indistinguishable from malignancy, which is more common; but in this setting, physicians should be alert to the differential diagnosis of fungal infections, since it can be equally deadly.

  12. Role of (18F) 2-fluoro-2-deoxyglucose positron emission tomography in upper gastrointestinal malignancies

    PubMed Central

    Smyth, Elizabeth C; Shah, Manish A

    2011-01-01

    The role of whole-body FDG [(18F) 2-fluoro-2-deoxyglucose] positron emission tomography (PET) scanning as an imaging modality in the management of patients with malignancy has evolved enormously over the past two decades. FDG-PET has demonstrated significant efficacy in the staging, prognostication and detection of occult metastatic disease in malignancies of the gastrointestinal tract, in addition to assessment of the response to cytotoxic chemotherapy in a more timely manner than has traditionally been possible by more conventional imaging tools. The sensitivity and specificity of FDG-PET for the detection and staging of malignancy depend not only on the site and size of the primary tumor and metastases, but also on histological cell type, reflecting underlying disparities in glucose metabolism. The metabolic response to neo-adjuvant chemotherapy or to chemo-radiotherapy in cancers of the gastro-esophageal junction or stomach has been demonstrated in several prospective studies to correlate significantly with both the histological tumor response to treatment and with consequent improvements in overall survival. This may offer a future paradigm of personalized treatment based on the PET response to chemotherapy. FDG-PET has been less successful in efforts to screen for and detect recurrent upper gastrointestinal malignancies, and in the detection of low volume metastatic peritoneal disease. Efforts to improve the accuracy of PET include the use of novel radiotracers such as (18F) FLT (3-deoxy-3-fluorothymidine) or 11C-choline, or fusion PET-CT with concurrent high-resolution computed tomography. This review focuses on the role of FDG-PET scanning in staging and response assessment in malignancies of the upper gastrointestinal tract, specifically gastric, esophageal and pancreas carcinoma. PMID:22171140

  13. Practical implementation of tetrahedral mesh reconstruction in emission tomography.

    PubMed

    Boutchko, R; Sitek, A; Gullberg, G T

    2013-05-01

    This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio

  14. Positron Emission Tomography Imaging Using Radiolabeled Inorganic Nanomaterials

    PubMed Central

    Sun, Xiaolian; Cai, Weibo; Chen, Xiaoyuan

    2015-01-01

    CONSPECTUS Positron emission tomography (PET) is a radionuclide imaging technology that plays an important role in preclinical and clinical research. With administration of a small amount of radiotracer, PET imaging can provide a noninvasive, highly sensitive, and quantitative readout of its organ/tissue targeting efficiency and pharmacokinetics. Various radiotracers have been designed to target specific molecular events. Compared with antibodies, proteins, peptides, and other biologically relevant molecules, nanoparticles represent a new frontier in molecular imaging probe design, enabling the attachment of different imaging modalities, targeting ligands, and therapeutic payloads in a single vector. We introduce the radiolabeled nanoparticle platforms that we and others have developed. Due to the fundamental differences in the various nanoparticles and radioisotopes, most radiolabeling methods are designed case-by-case. We focus on some general rules about selecting appropriate isotopes for given types of nanoparticles, as well as adjusting the labeling strategies according to specific applications. We classified these radiolabeling methods into four categories: (1) complexation reaction of radiometal ions with chelators via coordination chemistry; (2) direct bombardment of nanoparticles via hadronic projectiles; (3) synthesis of nanoparticles using a mixture of radioactive and nonradioactive precursors; (4) chelator-free postsynthetic radiolabeling. Method 1 is generally applicable to different nanomaterials as long as the surface chemistry is well-designed. However, the addition of chelators brings concerns of possible changes to the physicochemical properties of nanomaterials and detachment of the radiometal. Methods 2 and 3 have improved radiochemical stability. The applications are, however, limited by the possible damage to the nanocomponent caused by the proton beams (method 2) and harsh synthetic conditions (method 3). Method 4 is still in its infancy

  15. Evaluating Positron Emission Tomography Use in Differentiated Thyroid Cancer

    PubMed Central

    Esfandiari, Nazanene H.; Papaleontiou, Maria; Worden, Francis P.; Haymart, Megan R.

    2015-01-01

    Background: Using the Surveillance, Epidemiology, and End Results—Medicare database, a substantial increase was found in the use of positron emission tomography (PET) scans after 2004 in differentiated thyroid cancer (DTC) patients. The reason for the increased utilization of the PET scan was not clear based on available the data. Therefore, the indications for and outcomes of PET scans performed at an academic institution were evaluated. Methods: A retrospective cohort study was performed of DTC patients who underwent surgery at the University of Michigan Health System from 2006 to 2011. After identifying patients who underwent a PET scan, indications, rate of positive PET scans, and impact on management were evaluated. For positive scans, the location of disease was characterized, and presence of disease on other imaging was determined. Results: Of the 585 patients in the cohort, 111 (19%) patients had 200 PET scans performed for evaluation of DTC. Indications for PET scan included: elevated thyroglobulin and negative radioiodine scan in 52 scans (26.0%), thyroglobulin antibodies in 13 scans (6.5%), rising thyroglobulin in 18 scans (9.0%), evaluation of abnormality on other imaging in 22 scans (11.0%), evaluation of extent of disease in 33 scans (16.5%), follow-up of previous scan in 57 scans (28.5%), other indications in two scans (1.0%), and unclear indications in three scans (1.5%). The PET scan was positive in 124 studies (62.0%); positivity was identified in the thyroid bed on 25 scans, cervical or mediastinal lymph nodes on 105 scans, lung on 28 scans, bone on four scans, and other areas on 14 scans. Therapy following PET scan was surgery in 66 cases (33.0%), chemotherapy or radiation in 23 cases (11.5%), observation in 110 cases (55.0%), and palliative care in one case (0.5%). Disease was identifiable on other imaging in 66% of cases. PET scan results changed management in 59 cases (29.5%). Conclusions: In this academic medical center, the PET scan was

  16. TOPICAL REVIEW: Biological imaging in radiation therapy: role of positron emission tomography

    NASA Astrophysics Data System (ADS)

    Nestle, Ursula; Weber, Wolfgang; Hentschel, Michael; Grosu, Anca-Ligia

    2009-01-01

    In radiation therapy (RT), staging, treatment planning, monitoring and evaluation of response are traditionally based on computed tomography (CT) and magnetic resonance imaging (MRI). These radiological investigations have the significant advantage to show the anatomy with a high resolution, being also called anatomical imaging. In recent years, so called biological imaging methods which visualize metabolic pathways have been developed. These methods offer complementary imaging of various aspects of tumour biology. To date, the most prominent biological imaging system in use is positron emission tomography (PET), whose diagnostic properties have clinically been evaluated for years. The aim of this review is to discuss the valences and implications of PET in RT. We will focus our evaluation on the following topics: the role of biological imaging for tumour tissue detection/delineation of the gross tumour volume (GTV) and for the visualization of heterogeneous tumour biology. We will discuss the role of fluorodeoxyglucose-PET in lung and head and neck cancer and the impact of amino acids (AA)-PET in target volume delineation of brain gliomas. Furthermore, we summarize the data of the literature about tumour hypoxia and proliferation visualized by PET. We conclude that, regarding treatment planning in radiotherapy, PET offers advantages in terms of tumour delineation and the description of biological processes. However, to define the real impact of biological imaging on clinical outcome after radiotherapy, further experimental, clinical and cost/benefit analyses are required.

  17. Sensitivity estimation in time-of-flight list-mode positron emission tomography

    SciTech Connect

    Herraiz, J. L.; Sitek, A.

    2015-11-15

    Purpose: An accurate quantification of the images in positron emission tomography (PET) requires knowing the actual sensitivity at each voxel, which represents the probability that a positron emitted in that voxel is finally detected as a coincidence of two gamma rays in a pair of detectors in the PET scanner. This sensitivity depends on the characteristics of the acquisition, as it is affected by the attenuation of the annihilation gamma rays in the body, and possible variations of the sensitivity of the scanner detectors. In this work, the authors propose a new approach to handle time-of-flight (TOF) list-mode PET data, which allows performing either or both, a self-attenuation correction, and self-normalization correction based on emission data only. Methods: The authors derive the theory using a fully Bayesian statistical model of complete data. The authors perform an initial evaluation of algorithms derived from that theory and proposed in this work using numerical 2D list-mode simulations with different TOF resolutions and total number of detected coincidences. Effects of randoms and scatter are not simulated. Results: The authors found that proposed algorithms successfully correct for unknown attenuation and scanner normalization for simulated 2D list-mode TOF-PET data. Conclusions: A new method is presented that can be used for corrections for attenuation and normalization (sensitivity) using TOF list-mode data.

  18. Distinguishing tumor recurrence from irradiation sequelae with positron emission tomography in patients treated for larynx cancer

    SciTech Connect

    Greven, K.M.; Williams, D.W. III; Keyes, J.W. Jr.; McGuirt, W.F.; Harkness, B.A.; Watson, N.E. Jr.; Raben, M.; Frazier, L.C.; Geisinger, K.R.; Capellari, J.O.

    1994-07-01

    Distinguishing persistent or recurrent tumor from postradiation edema, or soft tissue/cartilage necrosis in patients treated for carcinoma of the larynx can be difficult. Because recurrent tumor is often submucosal, multiple deep biopsies may be necessary before a diagnosis can be established. Positron emission tomography with 18F-2-fluro-2-deoxglucose (FDG) was studied for its ability to aid in this problem. Positron emission tomography (18FDG) scans were performed on 11 patients who were suspected of having persistent or recurrent tumor after radiation treatment for carcinoma of the larynx. Patients underwent thorough history and physical examinations, scans with computerized tomography, and pathologic evaluation when indicated. Standard uptake values were used to quantitate the FDG uptake in the larynx. The time between completion of radiation treatment and positron emission tomography examination ranged from 2 to 26 months with a median of 6 months. Ten patients underwent computed tomography (CT) of the larynx, which revealed edema of the larynx (six patients), glottic mass (four patients), and cervical nodes (one patient). Positron emission tomography scans revealed increased FDG uptake in the larynx in five patients and laryngectomy confirmed the presence of carcinoma in these patients. Five patients had positron emission tomography results consistent with normal tissue changes in the larynx, and one patient had increased FDG uptake in neck nodes. This patient underwent laryngectomy, and no cancer was found in the primary site, but nodes were pathologically positive. One patient had slightly elevated FDG uptake and negative biopsy results. The remaining patients have been followed for 11 to 14 months since their positron emission studies and their examinations have remained stable. In patients without tumor, average standard uptake values of the larynx ranged from 2.4 to 4.7, and in patients with tumor, the range was 4.9 to 10.7. 18 refs., 3 figs., 1 tab.

  19. Bone single photon emission computed tomography with computed tomography disclosing chronic uterine perforation with intrauterine device migration into the anterior wall of the bladder: a case report

    PubMed Central

    2013-01-01

    Introduction Extraosseous uptake of 99mTc-hydroxymethylene diphosphonate is a common situation of variable clinical relevance. Case presentation A 52-year-old Caucasian woman presented to our department for breast cancer staging. A 99mTc-hydroxymethylene diphosphonate bone scan was performed and showed focal pelvic hyperfixation that disclosed intrauterine device migration into the anterior wall of the bladder on single photon emission computed tomography with computed tomography. Conclusion This observation confirms the major role of single photon emission computed tomography with computed tomography in achieving an exact diagnosis. PMID:23759143

  20. Adult granulosa cell tumor presenting with massive ascites, elevated CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography

    PubMed Central

    Tak, Ji Young; Park, Ji Y.; Lee, Seung Jeong; Lee, Yoon Hee; Hong, Dae Gy

    2015-01-01

    Adult granulosa cell tumors (AGCTs) presenting with massive ascites and elevated serum CA-125 levels have rarely been described in the literature. An ovarian mass, massive ascites, and elevated serum CA-125 levels in postmenopausal women generally suggest a malignant ovarian tumor, particularly advanced epithelial ovarian cancer. AGCT has low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography due to its low metabolic activity. In the present report, we describe a case of an AGCT with massive ascites, elevated serum CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography. PMID:26430671

  1. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines.

    PubMed

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H(α) (656 nm) and H(β) (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

  2. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines

    NASA Astrophysics Data System (ADS)

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission Hα (656 nm) and Hβ (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

  3. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines.

    PubMed

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H(α) (656 nm) and H(β) (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design. PMID:27036771

  4. The role of positron emission tomography/computed tomography in radiation therapy planning for patients with lung cancer.

    PubMed

    Mac Manus, Michael P; Hicks, Rodney J

    2012-09-01

    Positron emission tomography (PET)/computed tomography (CT) has rapidly assumed a critical role in the management of patients with locoregionally advanced lung cancers who are candidates for definitive radiation therapy (RT). Definitive RT is given with curative intent, but can only be successful in patients without distant metastasis and if all gross tumor is contained within the treated volume. An increasing body of evidence supports the use of PET-based imaging for selection of patients for both surgery and definitive RT. Similarly, the use of PET/CT images for accurate target volume definition in lung cancer is a dynamic area of research. Most available evidence on PET staging of lung cancer relates to non-small cell lung cancer (NSCLC). In general clinical use, (18)F-fluorodeoxyglucose (FDG) is the primary radiopharmaceutical useful in NSCLC. Other tracers, including proliferation markers and hypoxia tracers, may have significant roles in future. Much of the FDG-PET literature describing the impact of PET on actual patient management has concerned candidates for surgical resection. In the few prospective studies where PET was used for staging and patient selection in NSCLC candidates for definitive RT, 25%-30% of patients were denied definitive RT, generally because PET detected unsuspected advanced locoregional or distant metastatic disease. PET/CT and CT findings are often discordant in NSCLC but studies with clinical-pathological correlation always show that PET-assisted staging is more accurate than conventional assessment. In all studies in which "PET-defined" and "non-PET-defined" RT target volumes were compared, there were major differences between PET and non-PET volumes. Therefore, in cases where PET-assisted and non-PET staging are different and biopsy confirmation is unavailable, it is rational to use the most accurate modality (namely PET/CT) to define the target volume. The use of PET/CT in patient selection and target volume definition is likely

  5. Pretreatment Staging Positron Emission Tomography/Computed Tomography in Patients With Inflammatory Breast Cancer Influences Radiation Treatment Field Designs

    SciTech Connect

    Walker, Gary V.; Niikura, Naoki; Yang Wei; Rohren, Eric; Valero, Vicente; Woodward, Wendy A.; Alvarez, Ricardo H.; Lucci, Anthony; Ueno, Naoto T.; Buchholz, Thomas A.

    2012-08-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is increasingly being utilized for staging of inflammatory breast cancer (IBC). The purpose of this study was to define how pretreatment PET/CT studies affected postmastectomy radiation treatment (PMRT) planning decisions for IBC. Methods and Materials: We performed a retrospective analysis of 62 patients diagnosed with IBC between 2004 and 2009, who were treated with PMRT in our institution and who had a staging PET/CT within 3 months of diagnosis. Patients received a baseline physical examination, staging mammography, ultrasonographic examination of breast and draining lymphatics, and chest radiography; most patients also had a bone scan (55 patients), liver imaging (52 patients), breast MRI (46 patients), and chest CT (25 patients). We compared how PET/CT findings affected PMRT, assuming that standard PMRT would target the chest wall, level III axilla, supraclavicular fossa, and internal mammary chain (IMC). Any modification of target volumes, field borders, or dose prescriptions was considered a change. Results: PET/CT detected new areas of disease in 27 of the 62 patients (44%). The areas of additional disease included the breast (1 patient), ipsilateral axilla (1 patient), ipsilateral supraclavicular (4 patients), ipsilateral infraclavicular (1 patient), ipsilateral IMC (5 patients), ipsilateral subpectoral (3 patients), mediastinal (8 patients), other distant/contralateral lymph nodes (15 patients), or bone (6 patients). One patient was found to have a non-breast second primary tumor. The findings of the PET/CT led to changes in PMRT in 11 of 62 patients (17.7%). These changes included additional fields in 5 patients, adjustment of fields in 2 patients, and higher doses to the supraclavicular fossa (2 patients) and IMC (5 patients). Conclusions: For patients with newly diagnosed IBC, pretreatment PET/CT provides important information concerning involvement of locoregional lymph nodes

  6. Positron emission tomography as a diagnostic tool in infection: present role and future possibilities.

    PubMed

    Basu, Sandip; Chryssikos, Timothy; Moghadam-Kia, Siamak; Zhuang, Hongming; Torigian, Drew A; Alavi, Abass

    2009-01-01

    The past decade has witnessed the emergence of yet another promising application of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in the detection and management of patients with infection and inflammatory disorders. This phenomenon is quite evident when the peer-reviewed scientific literature is searched for on this topic. Among these scientific communications, the 6 conditions in which FDG-PET has demonstrated its greatest utility include (1) chronic osteomyelitis, (2) complicated lower-limb prostheses, (3) complicated diabetic foot, (4) fever of unknown origin, (5) acquired immunodeficiency syndrome (ie, AIDS), and (6) vascular graft infection and fistula. On the basis of published literature, orthopedic infections, particularly those related to implanted prostheses and osteomyelitis (including that occurring in the setting of a complicated diabetic foot), can be detected successfully by the use of FDG-PET and, therefore, this modality has great promise for becoming the study of choice in these complex settings. Increasingly, this technique is being used to detect infection in soft tissues, including those representing the sources of fever of unknown origin. The ability of FDG-PET to diagnose vascular graft infection and fistula, even when the anatomical imaging modalities are inconclusive, is of considerable interest to practitioners of vascular surgery. Combined PET/computed tomography (CT) imaging has the potential to determine the sites of infection or inflammation with high precision. The data on the role of PET/CT imaging in the assessment of infection and inflammation is sparse, but this combined modality approach may prove to be the study of choice in foreseeable future for precise localization of involved sites. However, the role of PET/CT may be limited in the presence of metallic artifacts (such as those caused by prostheses) adjacent to the sites of infection. PMID:19038599

  7. Miniature endoscopic optical coherence tomography for calculus detection.

    PubMed

    Kao, Meng-Chun; Lin, Chun-Li; Kung, Che-Yen; Huang, Yi-Fung; Kuo, Wen-Chuan

    2015-08-20

    The effective treatment of periodontitis involves the detection and removal of subgingival dental calculus. However, subgingival calculus is more difficult to detect than supragingival calculus because it is firmly attached to root surfaces within periodontal pockets. To achieve a smooth root surface, clinicians often remove excessive amounts of root structure because of decreased visibility. In addition, enamel pearl, a rare type of ectopic enamel formation on the root surface, can easily be confused with dental calculus in the subgingival environment. In this study, we developed a fiber-probe swept-source optical coherence tomography (SSOCT) technique and combined it with the quantitative measurement of an optical parameter [standard deviation (SD) of the optical coherence tomography (OCT) intensity] to differentiate subgingival calculus from sound enamel, including enamel pearl. Two-dimensional circumferential images were constructed by rotating the miniprobe (0.9 mm diameter) while acquiring image lines, and the adjacent lines in each rotation were stacked to generate a three-dimensional volume. In OCT images, compared to sound enamel and enamel pearls, dental calculus showed significant differences (P<0.001) in SD values. Finally, the receiver operating characteristic curve had a high capacity (area under the curve=0.934) for discriminating between healthy regions (including enamel pearl) and dental calculus. PMID:26368780

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

    PubMed

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

    2002-04-01

    The purpose of this retrospective study was to assess regional cerebral blood flow in patients after carbon monoxide intoxication by using brain single photon emission computed tomography and statistical parametric mapping. Eight patients with delayed neuropsychiatric sequelae and ten patients with no neuropsychiatric symptoms after carbon monoxide intoxication were studied with brain single photon emission tomography imaging with 99mTc-hexamethyl-propyleneamine oxime. Forty-four control subjects were also studied. We used the adjusted regional cerebral blood flow images in relative flow distribution (normalization of global cerebral blood flow for each subject to 50 ml x 100 g(-1) x min(-1) with proportional scaling) to compare these groups with statistical parametric mapping. Using this technique, significantly decreased regional cerebral blood flow was noted extensively in the bilateral frontal lobes as well as the bilateral insula and a part of the right temporal lobe in the patients with delayed neuropsychiatric sequelae as compared with normal volunteers (P< 0.005). In the patients with no neuropsychiatric symptoms, significantly decreased regional blood flow in the bilateral frontal lobes particularly on the left side was detected. There was a significantly decreased regional cerebral blood flow in the right frontal lobe and insula in the patients with delayed neuropsychiatric sequelae as compared to those with no neuropsychiatric sequelae. It is concluded that statistical parametric mapping is a useful technique for highlighting differences in regional cerebral blood flow in patients following carbon monoxide intoxication as compared with normal volunteers. The selectively reduced blood flow noted in this investigation supports the contention that the decrease following carbon monoxide intoxication may be prolonged and further worsen in the frontal lobe. In addition, the present study may help to clarify the characteristics of the pathophysiological

  9. Acoustic emission beamforming for enhanced damage detection

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory C.; Glaser, Steven D.; Grosse, Christian U.

    2008-03-01

    As civil infrastructure ages, the early detection of damage in a structure becomes increasingly important for both life safety and economic reasons. This paper describes the analysis procedures used for beamforming acoustic emission techniques as well as the promising results of preliminary experimental tests on a concrete bridge deck. The method of acoustic emission offers a tool for detecting damage, such as cracking, as it occurs on or in a structure. In order to gain meaningful information from acoustic emission analyses, the damage must be localized. Current acoustic emission systems with localization capabilities are very costly and difficult to install. Sensors must be placed throughout the structure to ensure that the damage is encompassed by the array. Beamforming offers a promising solution to these problems and permits the use of wireless sensor networks for acoustic emission analyses. Using the beamforming technique, the azmuthal direction of the location of the damage may be estimated by the stress waves impinging upon a small diameter array (e.g. 30mm) of acoustic emission sensors. Additional signal discrimination may be gained via array processing techniques such as the VESPA process. The beamforming approach requires no arrival time information and is based on very simple delay and sum beamforming algorithms which can be easily implemented on a wireless sensor or mote.

  10. Molecular Imaging of Transporters with Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Antoni, Gunnar; Sörensen, Jens; Hall, Håkan

    Positron emission tomography (PET) visualization of brain components in vivo is a rapidly growing field. Molecular imaging with PET is also increasingly used in drug development, especially for the determination of drug receptor interaction for CNS-active drugs. This gives the opportunity to relate clinical efficacy to per cent receptor occupancy of a drug on a certain targeted receptor and to relate drug pharmacokinetics in plasma to interaction with target protein. In the present review we will focus on the study of transporters, such as the monoamine transporters, the P-glycoprotein (Pgp) transporter, the vesicular monoamine transporter type 2, and the glucose transporter using PET radioligands. Neurotransmitter transporters are presynaptically located and in vivo imaging using PET can therefore be used for the determination of the density of afferent neurons. Several promising PET ligands for the noradrenaline transporter (NET) have been labeled and evaluated in vivo including in man, but a really useful PET ligand for NET still remains to be identified. The most promising tracer to date is (S,S)-[18F]FMeNER-D2. The in vivo visualization of the dopamine transporter (DAT) may give clues in the evaluation of conditions related to dopamine, such as Parkinson's disease and drug abuse. The first PET radioligands based on cocaine were not selective, but more recently several selective tracers such as [11C]PE2I have been characterized and shown to be suitable as PET radioligands. Although there are a large number of serotonin transporter inhibitors used today as SSRIs, it was not until very recently, when [11C]McN5652 was synthesized, that this transporter was studied using PET. New candidates as PET radioligands for the SERT have subsequently been developed and [11C]DASB and [11C]MADAM and their analogues are today the most promising ligands. The existing radioligands for Pgp transporters seem to be suitable tools for the study of both peripheral and central drug

  11. Detection of cocaine induced rat brain activation by photoacoustic tomography

    PubMed Central

    Jo, Janggun; Yang, Xinmai

    2011-01-01

    Photoacoustic tomography (PAT) was used to detect the progressive changes on the cerebral cortex of Sprague Dawley rats after the administration of cocaine hydrochloride. Different concentrations (0, 2.5, and 5.0 mg per kg body) of cocaine hydrochloride in saline solution were injected into Sprague Dawley rats through tail veins. Cerebral cortex images of the animals were continuously acquired by PAT. For continuous observation, PAT system used multi-transducers to reduce the scanning time and maintain a good signal-to-noise ratio (SNR). The obtained photoacoustic images were compared with each other and confirmed that changes in blood volume were induced by cocaine hydrochloride injection. The results demonstrate that PAT may be used to detect the effects of drug abuse-induced brain activation. PMID:21163301

  12. An atlas of Doppler emission-line tomography of cataclysmic variable stars

    NASA Technical Reports Server (NTRS)

    Kaitchuck, Ronald H.; Schlegel, Eric M.; Honeycutt, R. Kent; Horne, Keith; Marsh, T. R.; White, J. C., II; Mansperger, Cathy S.

    1994-01-01

    Doppler emission-line tomography is a technique similar to medical tomography. In this atlas the emission-line profiles of cataclysmic variable stars, seen at different orbital phases, are transformed into velocity space images. This transformation makes many of the complex line profile changes easier to interpret. The emission contributions of the disk and the s-wave are clearly separated in these images, and any emission from the stream and the secondary star can often be identified. In this atlas, Doppler tomograms of Hbeta, He I lambda 4471, and He II lambda 4686 emission lines of 18 cataclysmic variable stars are presented. The Doppler images provide insights into the individual systems and a better technique for measuring and radial velocity amplitude of the white dwarf.

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

    PubMed Central

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

    2016-01-01

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

  14. Motion artifact detection in four-dimensional computed tomography images

    NASA Astrophysics Data System (ADS)

    Bouilhol, G.; Ayadi, M.; Pinho, R.; Rit, S.; Sarrut, D.

    2014-03-01

    Motion artifacts appear in four-dimensional computed tomography (4DCT) images because of suboptimal acquisition parameters or patient breathing irregularities. Frequency of motion artifacts is high and they may introduce errors in radiation therapy treatment planning. Motion artifact detection can be useful for image quality assessment and 4D reconstruction improvement but manual detection in many images is a tedious process. We propose a novel method to evaluate the quality of 4DCT images by automatic detection of motion artifacts. The method was used to evaluate the impact of the optimization of acquisition parameters on image quality at our institute. 4DCT images of 114 lung cancer patients were analyzed. Acquisitions were performed with a rotation period of 0.5 seconds and a pitch of 0.1 (74 patients) or 0.081 (40 patients). A sensitivity of 0.70 and a specificity of 0.97 were observed. End-exhale phases were less prone to motion artifacts. In phases where motion speed is high, the number of detected artifacts was systematically reduced with a pitch of 0.081 instead of 0.1 and the mean reduction was 0.79. The increase of the number of patients with no artifact detected was statistically significant for the 10%, 70% and 80% respiratory phases, indicating a substantial image quality improvement.

  15. Fourier domain optical coherence tomography system with balance detection.

    PubMed

    Bradu, Adrian; Podoleanu, Adrian Gh

    2012-07-30

    A Fourier domain optical coherence tomography system with two spectrometers in balance detection is assembled using each an InGaAs linear camera. Conditions and adjustments of spectrometer parameters are presented to ensure anti-phase channeled spectrum modulation across the two cameras for a majority of wavelengths within the optical source spectrum. By blocking the signal to one of the spectrometers, the setup was used to compare the conditions of operation of a single camera with that of a balanced configuration. Using multiple layer samples, balanced detection technique is compared with techniques applied to conventional single camera setups, based on sequential deduction of averaged spectra collected with different on/off settings for the sample or reference beams. In terms of reducing the autocorrelation terms and fixed pattern noise, it is concluded that balance detection performs better than single camera techniques, is more tolerant to movement, exhibits longer term stability and can operate dynamically in real time. The cameras used exhibit larger saturation power than the power threshold where excess photon noise exceeds shot noise. Therefore, conditions to adjust the two cameras to reduce the noise when used in a balanced configuration are presented. It is shown that balance detection can reduce the noise in real time operation, in comparison with single camera configurations. However, simple deduction of an average spectrum in single camera configurations delivers less noise than the balance detection. PMID:23038305

  16. Spectral domain optical coherence tomography with dual-balanced detection

    NASA Astrophysics Data System (ADS)

    Bo, En; Liu, Xinyu; Chen, Si; Luo, Yuemei; Wang, Nanshuo; Wang, Xianghong; Liu, Linbo

    2016-03-01

    We developed a spectral domain optical coherence tomography (SD-OCT) system employing dual-balanced detection (DBD) for direct current term suppression and SNR enhancement, especially for auto-autocorrelation artifacts reduction. The DBD was achieved by using a beam splitter to building a free-space Michelson interferometer, which generated two interferometric spectra with a phase difference of π. These two phase-opposed spectra were guided to the spectrometer through two single mode fibers of the 8 fiber v-groove array and acquired by ultizing the upper two lines of a three-line CCD camera. We rotated this fiber v-groove array by 1.35 degrees to focus two spectra onto the first and second line of the CCD camera. Two spectra were aligned by optimum spectrum matching algorithm. By subtracting one spectrum from the other, this dual-balanced detection system achieved a direct current term suppression of ~30 dB, SNR enhancement of ~3 dB, and auto-autocorrelation artifacts reduction of ~10 dB experimentally. Finally we respectively validated the feasibility and performance of dual-balanced detection by imaging a glass plate and swine corneal tissue ex vivo. The quality of images obtained using dual-balanced detection was significantly improved with regard to the conventional single-detection (SD) images.

  17. Maturational changes in cerebral function in infants determined by /sup 18/FDG positron emission tomography

    SciTech Connect

    Chugani, H.T.; Phelps, M.E.

    1986-02-21

    2-Deoxy-2(/sup 18/F)fluro-D-glucose positron emission tomography performed in human infants during development revealed progressive changes in local cerebral glucose utilization. In infants 5 weeks of age and younger, glucose utilization was highest in the sensorimotor cortex, thalamus, midbrain-brainstem, and cerebellar vermis. By 3 months, glucose metabolic activity had increased in the parietal, temporal, and occipital cortices and the basal ganglia, with subsequent increases in frontal and various association regions occurring by 8 months. These functional changes measured with positron emission tomography are in agreement with behavioral, neurophysiological, and anatomical alterations known to occur during infant development. 32 references, 2 figures, 1 table.

  18. Target detection and quantification using a hybrid hand-held diffuse optical tomography and photoacoustic tomography system

    NASA Astrophysics Data System (ADS)

    Kumavor, Patrick D.; Xu, Chen; Aguirre, Andres; Gamelin, John; Ardeshirpour, Yasaman; Tavakoli, Behnoosh; Zanganeh, Saeid; Alqasemi, Umar; Yang, Yi; Zhu, Quing

    2011-04-01

    We present a photoacoustic tomography-guided diffuse optical tomography approach using a hand-held probe for detection and characterization of deeply-seated targets embedded in a turbid medium. Diffuse optical tomography guided by coregistered ultrasound, MRI, and x ray has demonstrated a great clinical potential to overcome lesion location uncertainty and to improve light quantification accuracy. However, due to the different contrast mechanisms, some lesions may not be detectable by a nonoptical modality but yet have high optical contrast. Photoacoustic tomography utilizes a short-pulsed laser beam to diffusively penetrate into tissue. Upon absorption of the light by the target, photoacoustic waves are generated and used to reconstruct, at ultrasound resolution, the optical absorption distribution that reveals optical contrast. However, the robustness of optical property quantification of targets by photoacoustic tomography is complicated because of the wide range of ultrasound transducer sensitivity, the orientation and shape of the targets relative to the ultrasound array, and the uniformity of the laser beam. We show in this paper that the relative optical absorption map provided by photoacoustic tomography can potentially guide the diffuse optical tomography to accurately reconstruct target absorption maps.

  19. Are we ready for positron emission tomography/computed tomography-based target volume definition in lymphoma radiation therapy?

    PubMed

    Yeoh, Kheng-Wei; Mikhaeel, N George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  20. Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings of Post Traumatic Lymphangioma in a Young Adult Male

    PubMed Central

    Kwon, Sang Don; Chun, Kyung Ah; Kong, Eun Jung; Cho, Ihn Ho

    2016-01-01

    The authors report the case of a 34-year-old male, who underwent a fluorine-18 fluoro deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan 7 years after trauma for the evaluation of multifocal masses in the right iliac and right inguinal areas. CT findings showed multifocal low density masses and 18F-FDG PET revealed slightly increased uptake (maximum standardized uptake value [SUVmax] 3.1). These findings did not exclude the possibility of a benign or malignant lesion. To achieve differential diagnosis, partial surgical excision was performed and a pathologic examination subsequently revealed lymphangioma. Here, the authors describe the 18F-FDG PET/CT findings of a rare case of lymphangioma resulting from trauma. PMID:27699163

  1. Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings of Post Traumatic Lymphangioma in a Young Adult Male

    PubMed Central

    Kwon, Sang Don; Chun, Kyung Ah; Kong, Eun Jung; Cho, Ihn Ho

    2016-01-01

    The authors report the case of a 34-year-old male, who underwent a fluorine-18 fluoro deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) scan 7 years after trauma for the evaluation of multifocal masses in the right iliac and right inguinal areas. CT findings showed multifocal low density masses and 18F-FDG PET revealed slightly increased uptake (maximum standardized uptake value [SUVmax] 3.1). These findings did not exclude the possibility of a benign or malignant lesion. To achieve differential diagnosis, partial surgical excision was performed and a pathologic examination subsequently revealed lymphangioma. Here, the authors describe the 18F-FDG PET/CT findings of a rare case of lymphangioma resulting from trauma.

  2. Bilateral Diffuse Fluorodeoxyglucose Uptake in Thyroid Gland Diagnosed by Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    PubMed Central

    Win, Aung Zaw; Aparici, Carina Mari

    2014-01-01

    Our patient is a female who was first diagnosed with breast cancer at the age of 23. A follow-up fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) at age 44 revealed diffuse high FDG uptake in an enlarged thyroid gland. Fine-needle aspiration (FNA) of the thyroid mass revealed estrogen receptor/progesterone receptor negative, human epidermal growth factor receptor 2+ breast cancer. To the best of our knowledge, this is the first case to report breast cancer metastasis to the thyroid in a diffuse pattern on FDG-PET/CT. Bilateral diffuse uptake of FDG in thyroid is the most commonly associated with benign conditions. However, FNA biopsies need to be done to rule out metastatic disease in thyroid lesions with diffuse high FDG uptake, especially for patients with history of cancer. PMID:25191131

  3. Are We Ready for Positron Emission Tomography/Computed Tomography-based Target Volume Definition in Lymphoma Radiation Therapy?

    SciTech Connect

    Yeoh, Kheng-Wei; Mikhaeel, N. George

    2013-01-01

    Fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has become indispensable for the clinical management of lymphomas. With consistent evidence that it is more accurate than anatomic imaging in the staging and response assessment of many lymphoma subtypes, its utility continues to increase. There have therefore been efforts to incorporate PET/CT data into radiation therapy decision making and in the planning process. Further, there have also been studies investigating target volume definition for radiation therapy using PET/CT data. This article will critically review the literature and ongoing studies on the above topics, examining the value and methods of adding PET/CT data to the radiation therapy treatment algorithm. We will also discuss the various challenges and the areas where more evidence is required.

  4. Imaging atherosclerosis with hybrid [18F]fluorodeoxyglucose positron emission tomography/computed tomography imaging: what Leonardo da Vinci could not see.

    PubMed

    Cocker, Myra S; Mc Ardle, Brian; Spence, J David; Lum, Cheemun; Hammond, Robert R; Ongaro, Deidre C; McDonald, Matthew A; Dekemp, Robert A; Tardif, Jean-Claude; Beanlands, Rob S B

    2012-12-01

    Prodigious efforts and landmark discoveries have led toward significant advances in our understanding of atherosclerosis. Despite significant efforts, atherosclerosis continues globally to be a leading cause of mortality and reduced quality of life. With surges in the prevalence of obesity and diabetes, atherosclerosis is expected to have an even more pronounced impact upon the global burden of disease. It is imperative to develop strategies for the early detection of disease. Positron emission tomography (PET) imaging utilizing [(18)F]fluorodeoxyglucose (FDG) may provide a non-invasive means of characterizing inflammatory activity within atherosclerotic plaque, thus serving as a surrogate biomarker for detecting vulnerable plaque. The aim of this review is to explore the rationale for performing FDG imaging, provide an overview into the mechanism of action, and summarize findings from the early application of FDG PET imaging in the clinical setting to evaluate vascular disease. Alternative imaging biomarkers and approaches are briefly discussed.

  5. Cosmic Ray Inspection and Passive Tomography for SNM Detection

    SciTech Connect

    Armitage, John; Oakham, Gerald; Bryman, Douglas; Cousins, Thomas; Noeel, Scott; Gallant, Grant; Jason, Andrew; Jonkmans, Guy; Stocki, Trevor J.; Waller, David

    2009-12-02

    The Cosmic Ray Inspection and Passive Tomography (CRIPT) project has recently started investigating the detection of illicit Special Nuclear Material in cargo using cosmic ray muon tomography and complementary neutron detectors. We are currently performing simulation studies to help with the design of small scale prototypes. Based on the prototype tests and refined simulations, we will determine whether the muon tracking system for the full scale prototype will be based on drift chambers or extruded scintillator trackers. An analysis of the operations of the Port of Montreal has determined how long muon scan times should take if all or a subset of the cargo is to be screened. As long as the throughput of the muon system(s) is equal to the rate at which containers are unloaded from ships, the impact on port operations would not be great if a muon scanning stage were required for all cargo. We also show preliminary simulation results indicating that excellent separation between Al, Fe and Pb is possible under ideal conditions. The discrimination power is reduced but still significant when realistic momentum resolution measurements are considered.

  6. A rare cardiac haemangioma in the right ventricle diagnosed accurately using ¹⁸F-fluorodeoxyglucose-positron emission tomography.

    PubMed

    Matsuba, Tomoyuki; Hisashi, Yosuke; Yotsumoto, Goichi; Imoto, Yutaka

    2015-05-01

    A right ventricular cardiac tumour was incidentally detected in a 61-year-old man during a preoperative examination for coronary artery bypass grafting (CABG). Findings on computed tomography and magnetic resonance imaging suggested the differential diagnoses of myxoma, haemangioma and haemangiosarcoma, and it was difficult to identify whether the tumour was benign or malignant. (18)F-fluorodeoxyglucose-positron emission tomography strongly suggested a benign tumour. We enucleated the tumour, because an intraoperative frozen section also strongly suggested a benign origin. After resection, CABG under cardiopulmonary bypass was performed. Histopathological and immunohistochemical analysis indicated a cavernous haemangioma without evidence of malignant tissue. The patient has survived 20 months after surgery with no evidence of tumour recurrence.

  7. Fossa navicularis magna detection on cone-beam computed tomography

    PubMed Central

    Mupparapu, Mel

    2016-01-01

    Herein, we report and discuss the detection of fossa navicularis magna, a close radiographic anatomic variant of canalis basilaris medianus of the basiocciput, as an incidental finding in cone-beam computed tomography (CBCT) imaging. The CBCT data of the patients in question were referred for the evaluation of implant sites and to rule out pathology in the maxilla and mandible. CBCT analysis showed osseous, notch-like defects on the inferior aspect of the clivus in all four cases. The appearance of fossa navicularis magna varied among the cases. In some, it was completely within the basiocciput and mimicked a small rounded, corticated, lytic defect, whereas it appeared as a notch in others. Fossa navicularis magna is an anatomical variant that occurs on the inferior aspect of the clivus. The pertinent literature on the anatomical variations occurring in this region was reviewed. PMID:27051639

  8. Fossa navicularis magna detection on cone-beam computed tomography.

    PubMed

    Syed, Ali Z; Mupparapu, Mel

    2016-03-01

    Herein, we report and discuss the detection of fossa navicularis magna, a close radiographic anatomic variant of canalis basilaris medianus of the basiocciput, as an incidental finding in cone-beam computed tomography (CBCT) imaging. The CBCT data of the patients in question were referred for the evaluation of implant sites and to rule out pathology in the maxilla and mandible. CBCT analysis showed osseous, notch-like defects on the inferior aspect of the clivus in all four cases. The appearance of fossa navicularis magna varied among the cases. In some, it was completely within the basiocciput and mimicked a small rounded, corticated, lytic defect, whereas it appeared as a notch in others. Fossa navicularis magna is an anatomical variant that occurs on the inferior aspect of the clivus. The pertinent literature on the anatomical variations occurring in this region was reviewed.

  9. The Role of 18F-Fluorodeoxyglucose Positron Emission Tomography in Thyroid Neoplasms

    PubMed Central

    Law, Tsz Ting

    2011-01-01

    18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has established itself as an important imaging modality in many oncological and nononcological specialties and, as a consequence, it is increasingly being used in clinical practice. Since the first report of FDG being taken up by metastatic differentiated thyroid carcinoma (DTC) cells >20 years ago, various groups of investigators have explored the potential role of FDG-PET scanning in patients with benign and malignant thyroid neoplasms. With the increasing demand for FDG-PET scanning, clinicians are faced with the challenge of managing an increasing number of FDG-PET–detected thyroid incidentalomas because their significance remains unclear. The aims of this review are to address some of these issues, specifically, the clinical significance of FDG-PET–detected thyroid incidentalomas, the ability of FDG-PET to characterize thyroid nodules, especially those with indeterminate fine needle aspiration cytology results, and the role of FDG-PET in patients with confirmed primary DTC and with suspected recurrent DTC, by reviewing the current literature. PMID:21378078

  10. Brain tumor imaging with synthesized /sup 18/F-fluorophenylalanine and positron emission tomography

    SciTech Connect

    Mineura, K.; Kowada, M.; Shishido, F.

    1989-06-01

    Two patients with cerebral gliomas were studied with 18F-fluorophenylalanine, newly synthesized by the electrophilic substitution reaction, using positron emission tomography. The tracer accumulated markedly in the tumor lesion and delineated the extent of the lesion. This new tracer will be promising in the diagnosis of gliomas.

  11. Positron Emission Tomography Methods with Potential for Increased Understanding of Mental Retardation and Developmental Disabilities

    ERIC Educational Resources Information Center

    Sundaram, Senthil K.; Chugani, Harry T.; Chugani, Diane C.

    2005-01-01

    Positron emission tomography (PET) is a technique that enables imaging of the distribution of radiolabeled tracers designed to track biochemical and molecular processes in the body after intravenous injection or inhalation. New strategies for the use of radiolabeled tracers hold potential for imaging gene expression in the brain during development…

  12. Attention Performance in Autism and Regional Brain Metabolic Rate Assessed by Positron Emission Tomography. Brief Report.

    ERIC Educational Resources Information Center

    Buchsbaum, M. S.; And Others

    1992-01-01

    This evaluation of seven high functioning adults with autism utilized positron emission tomography on a visual vigilance task. Although the subjects, as a group, did as well as normal controls on the task, there was a lack of normal hemispheric asymmetry in glucose metabolic rate. A heterogeneous etiology for autism is suggested to explain…

  13. 77 FR 8262 - Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... HUMAN SERVICES Food and Drug Administration Draft Guidance on Investigational New Drug Applications for Positron Emission Tomography Drugs; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA) is announcing the availability of a draft...

  14. The Neural Correlates of Driving Performance Identified Using Positron Emission Tomography

    ERIC Educational Resources Information Center

    Horikawa, E.; Okamura, N.; Tashiro, M.; Sakurada, Y.; Maruyama, M.; Arai, H.; Yamaguchi, K.; Sasaki, H.; Yanai, K.; Itoh, M.

    2005-01-01

    Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [^1^5O]H"2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and…

  15. Positron Emission Tomography in Cochlear Implant and Auditory Brainstem Implant Recipients.

    ERIC Educational Resources Information Center

    Miyamoto, Richard T.; Wong, Donald

    2001-01-01

    Positron emission tomography imaging was used to evaluate the brain's response to auditory stimulation, including speech, in deaf adults (five with cochlear implants and one with an auditory brainstem implant). Functional speech processing was associated with activation in areas classically associated with speech processing. (Contains five…

  16. Detection of atherosclerotic vascular tissue from optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Prakash, Ammu; Hewko, Mark; Sowa, Mike; Sherif, Sherif

    2012-10-01

    Atherosclerotic coronary artery disease continues to be one of the major causes of mortality. Prevention, diagnosis and treatment of atherosclerotic coronary artery disease are dependent on the detection of high risk atherosclerotic plaque. As age is one of the most important risk factors, atherosclerosis worsens steadily with increasing age. Automatic characterization of atherosclerotic plaque using the optical coherence tomography (OCT) images provides a powerful tool to classify patients with high risk plaque. In this study we develop an automatic classifier to detect atherosclerotic plaque in young and old Watanabe heritable hyperlipidemic (WHHL) rabbits, using OCT images without reliance on visual inspection. Our classifier based on texture analysis technique may provide an efficient tool for detecting invisible changes in tissue structure. We extracted a set of 22 statistical textural features for each image using the spatial gray level dependence matrix (SGLDM) method. An optimal scalar feature selection process was carried to select the best discriminating features that employ the Fisher discriminant ratio (FDR) criterion, and cross correlation measure between the pairs of features. Using these optimal features, we formed a combination of 5 best classification features using an exhaustive search method. A combined feature set was finally employed for the classification of plaque. We obtained correct classification rate and validation of 76.67% and 75% respectively.

  17. Nanoscale Cluster Detection in Massive Atom Probe Tomography Data

    SciTech Connect

    Seal, Sudip K; Yoginath, Srikanth B; Miller, Michael K

    2014-01-01

    Recent technological advances in atom probe tomography (APT) have led to unprecedented data acquisition capabilities that routinely generate data sets containing hundreds of millions of atoms. Detecting nanoscale clusters of different atom types present in these enormous amounts of data and analyzing their spatial correlations with one another are fundamental to understanding the structural properties of the material from which the data is derived. Extant algorithms for nanoscale cluster detection do not scale to large data sets. Here, a scalable, CUDA-based implementation of an autocorrelation algorithm is presented. It isolates spatial correlations amongst atomic clusters present in massive APT data sets in linear time using a linear amount of storage. Correctness of the algorithm is demonstrated using large synthetically generated data with known spatial distributions. Benefits and limitations of using GPU-acceleration for autocorrelation-based APT data analyses are presented with supporting performance results on data sets with up to billions of atoms. To our knowledge, this is the first nanoscale cluster detection algorithm that scales to massive APT data sets and executes on commodity hardware.

  18. Detection of early seizures by diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Hajihashemi, M. Reza; Zhou, Junli; Carney, Paul R.; Jiang, Huabei

    2015-03-01

    In epilepsy it has been challenging to detect early changes in brain activity that occurs prior to seizure onset and to map their origin and evolution for possible intervention. Besides, preclinical seizure experiments need to be conducted in awake animals with images reconstructed and displayed in real-time. We demonstrate using a rat model of generalized epilepsy that diffuse optical tomography (DOT) provides a unique functional neuroimaging modality for noninvasively and continuously tracking brain activities with high spatiotemporal resolution. We developed methods to conduct seizure experiments in fully awake rats using a subject-specific helmet and a restraining mechanism. For the first time, we detected early hemodynamic responses with heterogeneous patterns several minutes preceding the electroencephalographic seizure onset, supporting the presence of a "pre-seizure" state both in anesthetized and awake rats. Using a novel time-series analysis of scattering images, we show that the analysis of scattered diffuse light is a sensitive and reliable modality for detecting changes in neural activity associated with generalized seizure. We found widespread hemodynamic changes evolving from local regions of the bilateral cortex and thalamus to the entire brain, indicating that the onset of generalized seizures may originate locally rather than diffusely. Together, these findings suggest DOT represents a powerful tool for mapping early seizure onset and propagation pathways.

  19. Treatment of advanced solid tumours with NSAIDs: Correlation of quantitative monitoring of circulating tumour cells and positron emission tomography-computed tomography imaging

    PubMed Central

    Willecke-Hochmuth, Regina; Pachmann, Katharina; Drevs, Joachim

    2016-01-01

    The detection and characterisation of tumour-derived circulating epithelial tumor cells (CETCs) or circulating tumor cells (CTCs) have been a main focus of basic oncological research over previous years. Numerous studies in the past decade have shown that CTCs are a promising tool for the estimation of the risk for metastatic relapse. The present observational study describes treatment results using tumour imaging and the quantification of CTCs. A group of 14 patients with advanced carcinomas was followed during their anticancer treatments. CTC numbers were serially detected and treatment success was estimated by positron emission tomography-computed tomography. A connection was found between tumour remission and a decreasing CTC count in 83%, a connection between stable disease and stable CTC numbers in 78% and a connection between progressive disease (PD) and an increase in CTC count in 50% of cases. In the patients with PD, an incomplete response was observed affecting the CTCs, but not the solid region of the tumour. As a result of this study, it may be concluded that patients with solid tumours benefit from serial quantification of CTCs in addition to imaging, as this combination of techniques provides a more sensitive result than imaging alone. PMID:27588120

  20. Digital contrast enhancement of 18Fluorine-fluorodeoxyglucose positron emission tomography images in hepatocellular carcinoma

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Agarwal, Krishan Kant; Sharma, Punit; Bal, Chandrasekhar; Kumar, Rakesh

    2016-01-01

    Purpose: The role of 18fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrast enhancement technique. Materials and Methods: A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrast enhancement technique using 847 possible combinations of input parameters (threshold “m” and slope “e”). The input parameters which resulted in an image having a high value of 2nd order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. Results: The selected digital contrast enhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters “m” had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope “e” was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. Conclusion: The use of above digital contrast enhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted. PMID:26917889

  1. Positron Emission Tomography and Magnetic Resonance Imaging of Cellular Inflammation in Patients with Abdominal Aortic Aneurysms

    PubMed Central

    McBride, O.M.B.; Joshi, N.V.; Robson, J.M.J.; MacGillivray, T.J.; Gray, C.D.; Fletcher, A.M.; Dweck, M.R.; van Beek, E.J.R.; Rudd, J.H.F.; Newby, D.E.; Semple, S.I.

    2016-01-01

    Objectives Inflammation is critical in the pathogenesis of abdominal aortic aneurysm (AAA) disease. Combined 18F-fludeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET-CT) and ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) are non-invasive methods of assessing tissue inflammation. The aim of this study was to compare these techniques in patients with AAA. Materials and methods Fifteen patients with asymptomatic AAA with diameter 46 ± 7 mm underwent PET-CT with 18F-FDG, and T2*-weighted MRI before and 24 hours after administration of USPIO. The PET-CT and MRI data were then co-registered. Standardised uptake values (SUVs) were calculated to measure 18F-FDG activity, and USPIO uptake was determined using the change in R2*. Comparisons between the techniques were made using a quadrant analysis and a voxel-by-voxel evaluation. Results When all areas of the aneurysm were evaluated, there was a modest correlation between the SUV on PET-CT and the change in R2* on USPIO-enhanced MRI (n = 70,345 voxels; r = .30; p < .0001). Although regions of increased 18F-FDG and USPIO uptake co-localised on occasion, this was infrequent (kappa statistic 0.074; 95% CI 0.026–0.122). 18F-FDG activity was commonly focused in the shoulder region whereas USPIO uptake was more apparent in the main body of the aneurysm. Maximum SUV was lower in patients with mural USPIO uptake. Conclusions Both 18F-FDG PET-CT and USPIO-MRI uptake identify vascular inflammation associated with AAA. Although they demonstrate a modest correlation, there are distinct differences in the pattern and distribution of uptake, suggesting a differential detection of macrophage glycolytic and phagocytic activity respectively. PMID:26919936

  2. A Nonparametric Bayesian Approach For Emission Tomography Reconstruction

    NASA Astrophysics Data System (ADS)

    Barat, Éric; Dautremer, Thomas

    2007-11-01

    We introduce a PET reconstruction algorithm following a nonparametric Bayesian (NPB) approach. In contrast with Expectation Maximization (EM), the proposed technique does not rely on any space discretization. Namely, the activity distribution—normalized emission intensity of the spatial poisson process—is considered as a spatial probability density and observations are the projections of random emissions whose distribution has to be estimated. This approach is nonparametric in the sense that the quantity of interest belongs to the set of probability measures on Rk (for reconstruction in k-dimensions) and it is Bayesian in the sense that we define a prior directly on this spatial measure. In this context, we propose to model the nonparametric probability density as an infinite mixture of multivariate normal distributions. As a prior for this mixture we consider a Dirichlet Process Mixture (DPM) with a Normal-Inverse Wishart (NIW) model as base distribution of the Dirichlet Process. As in EM-family reconstruction, we use a data augmentation scheme where the set of hidden variables are the emission locations for each observed line of response in the continuous object space. Thanks to the data augmentation, we propose a Markov Chain Monte Carlo (MCMC) algorithm (Gibbs sampler) which is able to generate draws from the posterior distribution of the spatial intensity. A difference with EM is that one step of the Gibbs sampler corresponds to the generation of emission locations while only the expected number of emissions per pixel/voxel is used in EM. Another key difference is that the estimated spatial intensity is a continuous function such that there is no need to compute a projection matrix. Finally, draws from the intensity posterior distribution allow the estimation of posterior functionnals like the variance or confidence intervals. Results are presented for simulated data based on a 2D brain phantom and compared to Bayesian MAP-EM.

  3. Treatment modification of yttrium-90 radioembolization based on quantitative positron emission tomography/CT imaging.

    PubMed

    Chang, Ted T; Bourgeois, Austin C; Balius, Anastasia M; Pasciak, Alexander S

    2013-03-01

    Treatment activity for yttrium-90 ((90)Y) radioembolization when calculated by using the manufacturer-recommended technique is only partially patient-specific and may result in a subtumoricidal dose in some patients. The authors describe the use of quantitative (90)Y positron emission tomography/computed tomography as a tool to provide patient-specific optimization of treatment activity and evaluate this new method in a patient who previously received traditional (90)Y radioembolization. The modified treatment resulted in a 40-Gy increase in absorbed dose to tumor and complete resolution of disease in the treated area within 3 months.

  4. Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

    NASA Astrophysics Data System (ADS)

    Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

    2014-04-01

    In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

  5. Multilayer mirror based line emission tomography for spherical Tokamaks

    SciTech Connect

    Stutman, D.; Hwang, Y.S.; Menard, J.; Choe, W.; Ono, M.; Finkenthal, M.; May, M.J.; Regan, S.P.; Soukhanovskii, V.; Moos, H.W.

    1997-01-01

    Due to their highly shaped plasma and possible poloidal asymmetry in impurity concentration, spherical Tokamaks will require tomographic reconstruction of local emissivities to assess impurity content and transport. To collect in an effective manner the data required for such reconstruction, we develop arrays of high throughput {open_quotes}mini-monochromators{close_quotes} using extreme ultraviolet multilayer mirrors as dispersive elements and filtered surface barrier diodes as detectors. We discuss monochromator optimization and show that by working at near normal incidence throughput and spectral resolution are simultaneously maximized. A system proposed for tomographic reconstruction of CV and CVI resonance emission at 33.7 and 40.5 {Angstrom} respectively, achieves 0.9 {Angstrom} spectral resolution, 2 cm spatial resolution, and 0.2 ms temporal resolution, together with good sensitivity and background rejection. Preliminary results obtained from CDX-U low aspect ratio tokamak are also presented. {copyright} {ital 1997 American Institute of Physics.}

  6. Line emission tomography for CDX-U using filtered diodes

    SciTech Connect

    Stutman, D.; Menard, J.; Hwang, Y.S.; Choe, W.; Ono, M.; Finkenthal, M.; Soukhanovskii, V.; May, M.J.; Regan, S.P.; Moos, H.W.

    1997-01-01

    Electron density and temperature in the CDX-U low aspect ratio tokamak are too low to allow observation of fast magnetohydrodynamic activity using soft x-ray continuum emission. However, spectroscopic measurements show that extreme ultraviolet (XUV) line emission of intrinsic impurities is bright enough to observe such activity. In addition, a fast monitoring system for local temperature changes in the plasma core is required for planned auxiliary heating experiments. We present a spectrally resolved tomographic system for fast imaging of OVI 2s{endash}np, 2p{endash}nd (n{ge}3), CV 1s{sup 2}{endash}1s2p and CVI 1s{endash}2p XUV transitions. Using this emission, we can study both core and edge MHD activity, while the CVI to CV intensity ratio can indicate local changes in electron temperature. To achieve maximal throughput together with the needed spectral resolution, we use arrays of surface barrier diodes filtered with bandpass elemental filters. Using M edge filters (Zr, Pd, and Ag), we achieve both good discrimination between the above charge states and large transmission at the wavelengths of interest. Preliminary results obtained from CDX-U are presented. {copyright} {ital 1997 American Institute of Physics.}

  7. EndoTOFPET-US - A Miniaturised Calorimeter for Endoscopic Time-of-Flight Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Zvolský, Milan; EndoTOFPET-US Collaboration

    2015-02-01

    In the scope of the EndoTOFPET-US project, a novel multimodal device for Ultrasound (US) Endoscopy and Positron Emission Tomography (PET) is being developed. The project aims at detecting and quantifying morphologic and functional markers and developing new biomarkers for pancreas and prostate oncology. Exploiting the Time-of-Flight (TOF) information of the gamma rays allows for a more sensitive, more precise and lower radiation- dose imaging and intervention on small internal structures. The detection of the gamma rays is realised with the help of scintillator crystals with Silicon Photomultiplier (SiPM) read-out, aiming at a coincidence time resolution of 200 ps and a spatial resolution of ≈ 1 mm. For the endoscopic detector, digital SiPMs are utilised for the first time in an instrument planned for clinical applications. The functionality of the instrument as well as the challenges that accompany the high miniaturisation of the endoscopic detector and the asymmetric and variable geometry of the system, are presented. The demands on the system involve the fields of scintillating crystallography, ultra-fast photon detection, highly integrated electronics, system integration as well as image reconstruction. The single detector components have been fully characterised and are performing up to specifications. Two dedicated ASIC chips have been developed for the project. The first PET images have been acquired with a test setup that consists solely of hardware and software developed within the collaboration and demonstrate that the data acquisition and reconstruction chain is operational. In this talk, the characterisation of the single components and the status of the detector integration and comissioning is presented.

  8. Doppler tomography of XTE J1118+480 revealing chromospheric emission from the secondary star

    NASA Astrophysics Data System (ADS)

    Zurita, C.; González Hernández, J. I.; Escorza, A.; Casares, J.

    2016-08-01

    Doppler tomography of emission lines in low-mass X-ray binaries allows us to investigate the structure and variability of the accretion discs as well as possible activity arising from the secondary stars. We present Doppler maps of the black hole binary XTE J1118+480 from spectra obtained using OSIRIS@GTC during quiescence on four different nights in 2011 and 2012. Doppler imaging of the Hα line shows, for the first time, a narrow component from the secondary star with observed equivalent widths varying in the range 1.2-2.9 Å but not correlated with the veiling of the accretion disc. The Hα flux of the secondary star is too large to be powered by X-ray irradiation, supporting chromospheric activity, possibly induced by rapid rotation, as the most likely origin of this feature in the black hole X-ray binary XTE J1118+480. In addition, we detect variations in the centroid of the Hα line on nightly basis. These are likely caused by a precessing accretion disc, although with a much lower amplitude (˜50 km s-1) than previously observed.

  9. Positron Emission Tomography to Assess the Outcome of Intraportal Islet Transplantation.

    PubMed

    Eriksson, Olof; Selvaraju, Ramkumar; Eich, Torsten; Willny, Mariam; Brismar, Torkel B; Carlbom, Lina; Ahlström, Håkan; Tufvesson, Gunnar; Lundgren, Torbjörn; Korsgren, Olle

    2016-09-01

    No imaging methodology currently exists to monitor viable islet mass after clinical intraportal islet transplantation. We investigated the potential of the endocrine positron emission tomography (PET) marker [(11)C]5-hydroxytryptophan ([(11)C]5-HTP) for this purpose. In a preclinical proof-of-concept study, the ex vivo and in vivo [(11)C]5-HTP signal was compared with the number of islets transplanted in rats. In a clinical study, human subjects with an intraportal islet graft (n = 8) underwent two [(11)C]5-HTP PET and MRI examinations 8 months apart. The tracer concentration in the liver as a whole, or in defined hotspots, was correlated to measurements of islet graft function. In rat, hepatic uptake of [(11)C]5-HTP correlated with the number of transplanted islets. In human subjects, uptake in hepatic hotspots showed a correlation with metabolic assessments of islet function. Change in hotspot standardized uptake value (SUV) predicted loss of graft function in one subject, whereas hotspot SUV was unchanged in subjects with stable graft function. The endocrine marker [(11)C]5-HTP thus shows a correlation between hepatic uptake and transplanted islet function and promise as a tool for noninvasive detection of viable islets. The evaluation procedure described can be used as a benchmark for novel agents targeting intraportally transplanted islets. PMID:27325286

  10. The role of pallidal serotonergic function in Parkinson's disease dyskinesias: a positron emission tomography study.

    PubMed

    Smith, Ruben; Wu, Kit; Hart, Thomas; Loane, Clare; Brooks, David J; Björklund, Anders; Odin, Per; Piccini, Paola; Politis, Marios

    2015-04-01

    We have investigated the role of globus pallidus (GP) serotonergic terminals in the development of levodopa-induced dyskinesias (LIDs) in Parkinson's disease (PD). We studied 12 PD patients without LIDs, 12 PD patients with LIDs, and 12 healthy control subjects. We used (11)C-DASB positron emission tomography (PET), a marker of serotonin transporter availability, and (11)C-raclopride PET to measure changes in synaptic dopamine levels following levodopa administration. PD patients without LIDs showed a significant reduction of GP serotonin transporter binding compared with healthy controls although this was within the normal range in PD patients with LIDs. Levels of GP serotonin transporter binding correlated positively with severity of dyskinesias. (11)C-raclopride PET detected a significant rise in GP synaptic dopamine levels of patients with LIDs after a levodopa challenge but not in patients with a stable response. Our findings indicate that LIDs in PD are associated with higher GP serotonergic function. This increased serotonin function may result in further dysregulation of thalamocortical signals and so promote the expression of dyskinesias. PMID:25649022

  11. Neural correlates of malingering in mild traumatic brain injury: A positron emission tomography study.

    PubMed

    Spadoni, Andrea D; Kosheleva, Elena; Buchsbaum, Monte S; Simmons, Alan N

    2015-09-30

    The detection of malingering in cognitive performance is a challenge in clinical and legal environments. Neuroimaging may provide an objective method to determine the source of failure on tests of symptom validity. Participants comprised 45 combat veterans, 31 with mild traumatic brain injury (mTBI), not seeking medical or legal compensation, who completed the Tombaugh Test of Memory Malingering (TOMM) and a positron emission tomography (PET) scan. Based on TOMM performance (i.e., less than 45 of 50 total correct, suggesting suboptimal effort or malingering), subjects were separated into poor TOMM score (PT; n=10) and good TOMM score (GT; n=35) groups. Voxel-based multiple regression analysis with Group (GT/PT) predicting uptake of fluorodeoxyglucose revealed decreased brain metabolism in the ventromedial prefrontal cortex of poor performers. The current findings may suggest that poor TOMM performance in those with combat trauma and mTBI may be related to ventromedial prefrontal cortical dysfunction. These findings have important implications for the disentanglement of feigned versus actual memory impairment, where the latter may be secondary to neural mechanisms not consistent with forgetting or deception.

  12. Static stabilometry, transcranial Doppler, and single photon emission computed tomography in patients with central dizziness.

    PubMed

    Woolley, S M; Rubin, A M; Chronis, C B; Dailey, V; Bork, C E; Gerard, G

    1994-11-01

    Previous studies have found that transcranial doppler (TCD) and single photon emission computed tomography (SPECT) are effective means of diagnosing cerebral blood flow disorders in patients with central dizziness whose etiology was unknown by standard audiologic and/or vestibular assessment techniques. Also, static stabilometry, which measures a person's standing center of pressure (COP) movements, has been used to distinguish between patients with central neurologic and peripheral vestibular disorders. The purpose of this retrospective study was to examine the relation between TCD, SPECT, and stabilometry in patients with central dizziness attributable to cerebral blood flow disorders. Stabilometry testing was conducted on 50 normal subjects and 31 subjects with dizziness, the latter group consisting of persons with cerebral dysautoregulation, migraines, and unknown etiology with negative or positive SPECT results. The results indicated that patients with cerebral dysautoregulation were not significantly different from normal subjects or the other three groups in their COP movements. The other three groups exhibited significantly higher COP movements than the normal subjects, particularly when visual inputs were compromised. Patients with negative SPECT results were significantly different in their COP movements from the other three groups of subjects with dizziness. These results suggest that the pattern of COP movements may be useful in identifying patients with postural dysfunctions whose etiology may then be detected by TCD and SPECT.

  13. 18F-Fluorodeoxyglucose Positron Emission Tomography/CT Scanning in Diagnosing Vascular Prosthetic Graft Infection

    PubMed Central

    Saleem, Ben R.; Pol, Robert A.; Slart, Riemer H. J. A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2014-01-01

    Vascular prosthetic graft infection (VPGI) is a severe complication after vascular surgery. CT-scan is considered the diagnostic tool of choice in advanced VPGI. The incidence of a false-negative result using CT is relatively high, especially in the presence of low-grade infections. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) scanning has been suggested as an alternative for the diagnosis and assessment of infectious processes. Hybrid 18F-FDG PET/CT has established the role of 18F-FDG PET for the assessment of suspected VPGI, providing accurate anatomic localization of the site of infection. However, there are no clear guidelines for the interpretation of the uptake patterns of 18F-FDG as clinical tool for VPGI. Based on the available literature it is suggested that a linear, diffuse, and homogeneous uptake should not be regarded as an infection whereas focal or heterogeneous uptake with a projection over the vessel on CT is highly suggestive of infection. Nevertheless, 18F-FDG PET and 18F-FDG PET/CT can play an important role in the detection of VPGI and monitoring response to treatment. However an accurate uptake and pattern recognition is warranted and cut-off uptake values and patterns need to be standardized before considering the technique to be the new standard. PMID:25210712

  14. Insights Into Microcirculation Underlying Critical Limb Ischemia by Single-Photon Emission Computed Tomography

    PubMed Central

    Liu, Jung-Tung; Chang, Cheng-Siu; Su, Chen-Hsing; Li, Cho-Shun

    2015-01-01

    Abstract Perfusion difference is used as a parameter to evaluate microcirculation. This study aims to differentiate lower-limb perfusion insufficiency from neuropathy to prevent possible occurrence of failed back surgery syndrome (FBSS). Patients were retrospectively gathered from 134 FBSS cases diagnosed in the past 7 years. Up to 82 cases that were excluded from neuralgia by radiologic imaging, electrodiagnostic electromyography, and nerve conduction velocity were enrolled in this study. Perfusion difference was evaluated by single-photon emission computed tomography, and pain intensities were recorded via visual analog scale (VAS) score. Lower perfusion at the left leg comprises 51.2% (42 of 82) of the patients. The mean perfusion difference of the 82 patients was 0.86 ± 0.05 (range: 0.75–0.93). Patients with systemic vascular diseases exhibited significantly higher perfusion difference than that of patients without these related diseases (P < 0.05), except for renal insufficiency (P = 0.134). Significant correlation was observed between perfusion difference and VAS score (r = −0.78; P < 0.0001; n = 82). In this study, we presented perfusion difference as a parameter for evaluating microcirculation, which cannot be detected by ultrasonography or angiography. PMID:26166084

  15. Initial characterization of a BGO-photodiode detector for high resolution positron emission tomography

    SciTech Connect

    Derenzo, S.E.

    1983-11-01

    Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO crystal coupled only to an SPD can achieve a 511 keV photopeak resolution of 8.7% FWHM at -150/sup 0/C, using a pulse peaking time of 10 ..mu..s. When two 3 mm x 3 mm x 15 mm BGO crystals are coupled individually to SPDs and also coupled to a common 14 mm diam PMT, the SPDs detect the 511 keV photopeak with a resolution of 30% FWHM at -76/sup 0/C. In coincidence with an opposing 3 mm wide BGO crystal, the SPDs are able to identify the crystal of interaction with good signal-to-noise ratio, and the detector pair resolution is 2 mm FWHM. 32 references, 7 figures, 3 tables.

  16. A New Positron Emission Tomography (PET) Radioligand for Imaging Sigma-1 Receptors in Living Subjects

    PubMed Central

    Zavaleta, Cristina L.; Nielsen, Carsten H.; Mesangeau, Christophe; Vuppala, Pradeep K.; Chan, Carmel; Avery, Bonnie A.; Fishback, James A.; Matsumoto, Rae R.; Gambhir, Sanjiv S.; McCurdy, Christopher R.; Chin, Frederick T.

    2014-01-01

    Sigma-1 receptor (S1R) radioligands have the potential to detect and monitor various neurological diseases. Herein we report the synthesis, radiofluorination and evaluation of a new S1R ligand 6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one ([18F]FTC-146, [18F]13). [18F]13 was synthesized by nucleophilic fluorination, affording a product with >99% radiochemical purity (RCP) and specific activity (SA) of 2.6 ± 1.2 Ci/Amol (n = 13) at end of synthesis (EOS). Positron emission tomography (PET) and ex vivo autoradiography studies of [18F]13 in mice showed high uptake of the radioligand in S1R rich regions of the brain. Pre treatment with 1 mg/kg haloperidol (2), non radioactive 13, or BD1047 (18) reduced the binding of [18F]13 in the brain at 60 min by 80%, 82% and 81% respectively, suggesting that [18F]13 accumulation in mouse brain represents specific binding to S1Rs. These results indicate that [18F]13 is a promising candidate radiotracer for further evaluation as a tool for studying S1Rs in living subjects. PMID:22853801

  17. The metabolic landscape of cortico-basal ganglionic degeneration: regional asymmetries studied with positron emission tomography.

    PubMed Central

    Eidelberg, D; Dhawan, V; Moeller, J R; Sidtis, J J; Ginos, J Z; Strother, S C; Cederbaum, J; Greene, P; Fahn, S; Powers, J M

    1991-01-01

    Regional metabolic rate for glucose (rCMRGlc) was estimated using [18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) in five patients (four men, one woman; mean age 68; mean disease duration 2.4 years) with clinical findings consistent with the syndrome of cortico-basal ganglionic degeneration (CBGD). Left-right rCMRGlc asymmetry, (L-R)/(L + R) x 100, was calculated for 13 grey matter regions and compared with regional metabolic data from 18 normal volunteers and nine patients with asymmetrical Parkinson's disease (PD). In the CBGD group mean metabolic asymmetry values in the thalamus, inferior parietal lobule and hippocampus were greater than those measured in normal control subjects and patients with asymmetrical PD (p less than 0.02). Parietal lobe asymmetry of 5% or more was evident in all CBGD patients, whereas in PD patients and normal controls, all regional asymmetry measures were less than 5% in absolute value. Measures of frontal, parietal and hemispheric metabolic asymmetry were found to be positively correlated with asymmetries in thalamic rCMRGlc (p less than 0.05). The presence of cortico-thalamic metabolic asymmetry is consistent with the focal neuropathological changes reported in CBGD brains. Our findings suggest that metabolic asymmetries detected with FDG/PET may support a diagnosis of CBGD in life. Images PMID:1744638

  18. Quantitative experimental monitoring of molecular diffusion in clay with positron emission tomography

    NASA Astrophysics Data System (ADS)

    Kulenkampff, Johannes; Zakhnini, Abdelhamid; Gründig, Marion; Lippmann-Pipke, Johanna

    2016-08-01

    Clay plays a prominent role as barrier material in the geosphere. The small particle sizes cause extremely small pore sizes and induce low permeability and high sorption capacity. Transport of dissolved species by molecular diffusion, driven only by a concentration gradient, is less sensitive to the pore size. Heterogeneous structures on the centimetre scale could cause heterogeneous effects, like preferential transport zones, which are difficult to assess. Laboratory measurements with diffusion cells yield limited information on heterogeneity, and pore space imaging methods have to consider scale effects. We established positron emission tomography (PET), applying a high-resolution PET scanner as a spatially resolved quantitative method for direct laboratory observation of the molecular diffusion process of a PET tracer on the prominent scale of 1-100 mm. Although PET is rather insensitive to bulk effects, quantification required significant improvements of the image reconstruction procedure with respect to Compton scatter and attenuation. The experiments were conducted with 22Na and 124I over periods of 100 and 25 days, respectively. From the images we derived trustable anisotropic diffusion coefficients and, in addition, we identified indications of preferential transport zones. We thus demonstrated the unique potential of the PET imaging modality for geoscientific process monitoring under conditions where other methods fail, taking advantage of the extremely high detection sensitivity that is typical of radiotracer applications.

  19. Positron Emission Tomography Imaging of Tumor Cell Metabolism and Application to Therapy Response Monitoring

    PubMed Central

    Challapalli, Amarnath; Aboagye, Eric O.

    2016-01-01

    Cancer cells do reprogram their energy metabolism to enable several functions, such as generation of biomass including membrane biosynthesis, and overcoming bioenergetic and redox stress. In this article, we review both established and evolving radioprobes developed in association with positron emission tomography (PET) to detect tumor cell metabolism and effect of treatment. Measurement of enhanced tumor cell glycolysis using 2-deoxy-2-[18F]fluoro-D-glucose is well established in the clinic. Analogs of choline, including [11C]choline and various fluorinated derivatives are being tested in several cancer types clinically with PET. In addition to these, there is an evolving array of metabolic tracers for measuring intracellular transport of glutamine and other amino acids or for measuring glycogenesis, as well as probes used as surrogates for fatty acid synthesis or precursors for fatty acid oxidation. In addition to providing us with opportunities for examining the complex regulation of reprogramed energy metabolism in living subjects, the PET methods open up opportunities for monitoring pharmacological activity of new therapies that directly or indirectly inhibit tumor cell metabolism. PMID:26973812

  20. Imaging of Tumor Metabolism Using Positron Emission Tomography (PET).

    PubMed

    Apostolova, Ivayla; Wedel, Florian; Brenner, Winfried

    2016-01-01

    Molecular imaging employing PET/CT enables in vivo visualization, characterization, and measurement of biologic processes in tumors at a molecular and cellular level. Using specific metabolic tracers, information about the integrated function of multiple transporters and enzymes involved in tumor metabolic pathways can be depicted, and the tracers can be directly applied as biomarkers of tumor biology. In this review, we discuss the role of F-18-fluorodeoxyglucose (FDG) as an in vivo glycolytic marker which reflects alterations of glucose metabolism in cancer cells. This functional molecular imaging technique offers a complementary approach to anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI) and has found widespread application as a diagnostic modality in oncology to monitor tumor biology, optimize the therapeutic management, and guide patient care. Moreover, emerging methods for PET imaging of further biologic processes relevant to cancer are reviewed, with a focus on tumor hypoxia and aberrant tumor perfusion. Hypoxic tumors are associated with poor disease control and increased resistance to cytotoxic and radiation treatment. In vivo imaging of hypoxia, perfusion, and mismatch of metabolism and perfusion has the potential to identify specific features of tumor microenvironment associated with poor treatment outcome and, thus, contribute to personalized treatment approaches. PMID:27557539

  1. A Conway-Maxwell-Poisson (CMP) model to address data dispersion on positron emission tomography.

    PubMed

    Santarelli, Maria Filomena; Della Latta, Daniele; Scipioni, Michele; Positano, Vincenzo; Landini, Luigi

    2016-10-01

    Positron emission tomography (PET) in medicine exploits the properties of positron-emitting unstable nuclei. The pairs of γ- rays emitted after annihilation are revealed by coincidence detectors and stored as projections in a sinogram. It is well known that radioactive decay follows a Poisson distribution; however, deviation from Poisson statistics occurs on PET projection data prior to reconstruction due to physical effects, measurement errors, correction of deadtime, scatter, and random coincidences. A model that describes the statistical behavior of measured and corrected PET data can aid in understanding the statistical nature of the data: it is a prerequisite to develop efficient reconstruction and processing methods and to reduce noise. The deviation from Poisson statistics in PET data could be described by the Conway-Maxwell-Poisson (CMP) distribution model, which is characterized by the centring parameter λ and the dispersion parameter ν, the latter quantifying the deviation from a Poisson distribution model. In particular, the parameter ν allows quantifying over-dispersion (ν<1) or under-dispersion (ν>1) of data. A simple and efficient method for λ and ν parameters estimation is introduced and assessed using Monte Carlo simulation for a wide range of activity values. The application of the method to simulated and experimental PET phantom data demonstrated that the CMP distribution parameters could detect deviation from the Poisson distribution both in raw and corrected PET data. It may be usefully implemented in image reconstruction algorithms and quantitative PET data analysis, especially in low counting emission data, as in dynamic PET data, where the method demonstrated the best accuracy. PMID:27522237

  2. 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.

  3. The Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Bone Lesions of Undetermined Origin.

    PubMed

    Tamam, Cuneyt; Tamam, Muge; Mulazimoglu, Mehmet

    2016-01-01

    The aim of the current study was to determine the diagnostic accuracy of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting carcinoma of unknown primary (CUP) with bone metastases. We evaluated 87 patients who were referred to FDG-PET/CT imaging and reported to have skeletal lesions with suspicion of malignancy. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. The median survival rate was measured to evaluate the prognostic value of the FDG-PET/CT findings. In the search for a primary, FDG-PET/CT findings correctly diagnosed lesions as the site of the primary true positive (TP) in 64 (73%) cases, 4 (5%) findings diagnosed no site of a primary, and none were subsequently proven to be true negative (TN); 14 (16%) diagnoses were false positive (FP) and 5 (6%) diagnoses were false negative (FN). Life expectancy was between 2 months and 25 months. Whole-body FDG-PET/CT imaging may be a useful method in assessing the bone lesions with suspicion of bone metastases. PMID:27134563

  4. Multislice computer tomography for detection of coronary artery disease.

    PubMed

    Ropers, Dieter

    2006-12-01

    Multislice computer tomography has undergone substantial technological progress during the past years. Current 64-slice scanners with gantry rotation speeds of as little as 330 ms, and particularly the recently introduced dual source CT equipped with two X-ray tubes, provide a temporal and spatial resolution that is sufficient to allow reliable imaging of cardiac morphology and coronary arteries. Especially the ability to noninvasively visualize the coronary arteries, including the assessment and quantification of calcifications, as well as the detection of luminal obstruction and atherosclerotic plaque, constitutes an attractive addition to currently available diagnostic tools for the work-up of patients with known or suspected coronary artery disease. Besides the evaluation of coronary artery calcium and atherosclerotic plaques, this review focuses on the contrast-enhanced CT visualization of the coronary vessels, including native coronary arteries, bypass grafts, and coronary stonts. Thereby detailed information concerning the scan protocol, clinical data, possible indications, and limitations using up-to-date 64-slice technology is provided. Finally, the overview includes design and initial image examples of dual source CT technology as the newest development in the field.

  5. Detection of CN Emission from (2060) Chiron.

    PubMed

    Bus, S J; A'hearn, M F; Schleicher, D G; Bowell, E

    1991-02-15

    In the past decade there has been a gradual, but substantial change in our understanding of the physical nature of (2060) Chiron. Once thought to be the first known member of a population of asteroids orbiting between Saturn and Uranus, Chiron is now generally regarded as the largest known comet. The detection of CN emission in the spectrum of Chiron is reported. Not only do these observations underscore the cometary nature of Chiron, but, at a heliocentric distance exceeding 11 astronomical units, represent the most distant detection yet of a neutral gas species common in comets. These results are consistent with the outgassing from Chiron being primarily driven by isolated outbursts of CO(2) from a very small fraction of Chiron's surface. These may be indicative of primordial inhomogeneities.

  6. [Examination of myocardial perfusion with positron emission tomography: a clinically useful and valid method?].

    PubMed

    vom Dahl, J

    1997-02-01

    Positron emission tomography (PET) of the heart has gained widespread scientific and clinical acceptance with regard to 2 indications: 1. the detection of perfusion abnormalities by qualitative and semiquantitative analyses of perfusion images at rest and during physical or pharmacological stress using well validated perfusion tracers such as N-13 ammonia, Rb-82 rubidiumchloride, or O-15 labeled water, 2. Viability imaging of myocardial regions with reduced contractility by combining perfusion measurements with substrate metabolism as assessed from F-18 deoxyglucose utilization. This overview summarizes the use of PET as a perfusion imaging method. With a sensitivity > 90% in combination with a high specificity, PET is today the best available nuclear imaging technique for the diagnosis of coronary artery disease (CAD). The short half-life of the perfusion tracers in combination with highly sophisticated hard- and software enables rapid PET studies with high patient throughput. The high diagnostic accuracy and the methological advantages as compared to conventional scintigraphy allows to use PET perfusion imaging for detection of subtle changes of the perfusion reserve for detection of CAD in high risk but asymptomatic patients as well as in patients with proven CAD undergoing various treatment forms such as risk factor reduction or coronary revascularization. In patients following orthotopic heart transplantation, evolving transplant vasculopathy can be detected at an early stage. Quantitative PET imaging at rest allows for detection of myocardial viability since cellular survival is based on maintenance of a minimal perfusion and structural changes correlate to the degree of perfusion reduction. Furthermore, quantitative assessment of the myocardial perfusion reserve detects the magnitude and competence of collaterals in regions with occluded epicardial arteries and thus, imaging of several coronary distribution territories in one noninvasive study. The cost of

  7. The Promise and Pitfalls of Positron Emission Tomography and Single-Photon Emission Computed Tomography Molecular Imaging–Guided Radiation Therapy

    PubMed Central

    Wahl, Richard L.; Herman, Joseph M.; Ford, Eric

    2015-01-01

    External beam radiation therapy procedures have, until recently, been planned almost exclusively using anatomic imaging methods. Molecular imaging using hybrid positron emission tomography (PET)/computed tomography scanning or single-photon emission computed tomography (SPECT) imaging has provided new insights into the precise location of tumors (staging) and the extent and character of the biologically active tumor volume (BTV) and has provided differential response information during and after therapy. In addition to the commonly used radiotracer 18F-fluoro- 2-deoxyD-glucose (FDG), additional radiopharmaceuticals are being explored to image major physiological processes as well as tumor biological properties, such as hypoxia, proliferation, amino acid accumulation, apoptosis, and receptor expression, providing the potential to target or boost the radiation dose to a biologically relevant region within a tumor, such as the most hypoxic or most proliferative area. Imaging using SPECT agents has furthered the possibility of limiting dose to functional normal tissues. PET can also portray the distribution of particle therapy by displaying activated species in situ. With both PET and SPECT imaging, fundamental physical issues of limited spatial resolution relative to the biological process, partial volume effects for quantification of small volumes, image misregistration, motion, and edge delineation must be carefully considered and can differ by agent or the method applied. Molecular imaging–guided radiation therapy (MIGRT) is a rapidly evolving and promising area of investigation and clinical translation. As MIGRT evolves, evidence must continue to be gathered to support improved clinical outcomes using MIGRT versus purely anatomic approaches. PMID:21356477

  8. 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

  9. Positron emission tomography-computed tomography in the diagnostic evaluation of smoldering multiple myeloma: identification of patients needing therapy

    PubMed Central

    Siontis, B; Kumar, S; Dispenzieri, A; Drake, M T; Lacy, M Q; Buadi, F; Dingli, D; Kapoor, P; Gonsalves, W; Gertz, M A; Rajkumar, S V

    2015-01-01

    We studied 188 patients with a suspected smoldering multiple myeloma (MM) who had undergone a positron emission tomography-computed tomography (PET-CT) scan as part of their clinical evaluation. PET-CT was positive (clinical radiologist interpretation of increased bone uptake and/or evidence of lytic bone destruction) in 74 patients and negative in 114 patients. Of these, 25 patients with a positive PET-CT and 97 patients with a negative PET-CT were observed without therapy and formed the study cohort (n=122). The probability of progression to MM within 2 years was 75% in patients with a positive PET-CT observed without therapy compared with 30% in patients with a negative PET-CT; median time to progression was 21 months versus 60 months, respectively, P=0.0008. Of 25 patients with a positive PET-CT, the probability of progression was 87% at 2 years in those with evidence of underlying osteolysis (n=16) and 61% in patients with abnormal PET-CT uptake but no evidence of osteolysis (n=9). Patients with positive PET-CT and evidence of underlying osteolysis have a high risk of progression to MM within 2 years when observed without therapy. These observations support recent changes to imaging requirements in the International Myeloma Working Group updated diagnostic criteria for MM. PMID:26495861

  10. 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography/computed tomography imaging in paediatric oncology

    PubMed Central

    Freebody, John; Wegner, Eva A; Rossleigh, Monica A

    2014-01-01

    Positron emission tomography (PET) is a minimally invasive technique which has been well validated for the diagnosis, staging, monitoring of response to therapy, and disease surveillance of adult oncology patients. Traditionally the value of PET and PET/computed tomography (CT) hybrid imaging has been less clearly defined for paediatric oncology. However recent evidence has emerged regarding the diagnostic utility of these modalities, and they are becoming increasingly important tools in the evaluation and monitoring of children with known or suspected malignant disease. Important indications for 2-deoxy-2-(18F)fluoro-D-glucose (FDG) PET in paediatric oncology include lymphoma, brain tumours, sarcoma, neuroblastoma, Langerhans cell histiocytosis, urogenital tumours and neurofibromatosis type I. This article aims to review current evidence for the use of FDG PET and PET/CT in these indications. Attention will also be given to technical and logistical issues, the description of common imaging pitfalls, and dosimetric concerns as they relate to paediatric oncology. PMID:25349660

  11. Impact of Pretreatment Combined {sup 18}F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Staging on Radiation Therapy Treatment Decisions in Locally Advanced Breast Cancer

    SciTech Connect

    Ng, Sweet Ping; David, Steven; Alamgeer, Muhammad; Ganju, Vinod

    2015-09-01

    Purpose: To assess the diagnostic performance of pretreatment {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) and its impact on radiation therapy treatment decisions in patients with locally advanced breast cancer (LABC). Methods and Materials: Patients with LABC with Eastern Cooperative Oncology Group performance status <2 and no contraindication to neoadjuvant chemotherapy, surgery, and adjuvant radiation therapy were enrolled on a prospective trial. All patients had pretreatment conventional imaging (CI) performed, including bilateral breast mammography and ultrasound, bone scan, and CT chest, abdomen, and pelvis scans performed. Informed consent was obtained before enrolment. Pretreatment whole-body {sup 18}F-FDG PET/CT scans were performed on all patients, and results were compared with CI findings. Results: A total of 154 patients with LABC with no clinical or radiologic evidence of distant metastases on CI were enrolled. Median age was 49 years (range, 26-70 years). Imaging with PET/CT detected distant metastatic disease and/or locoregional disease not visualized on CI in 32 patients (20.8%). Distant metastatic disease was detected in 17 patients (11.0%): 6 had bony metastases, 5 had intrathoracic metastases (pulmonary/mediastinal), 2 had distant nodal metastases, 2 had liver metastases, 1 had pulmonary and bony metastases, and 1 had mediastinal and distant nodal metastases. Of the remaining 139 patients, nodal disease outside conventional radiation therapy fields was detected on PET/CT in 15 patients (10.8%), with involvement of ipsilateral internal mammary nodes in 13 and ipsilateral level 5 cervical nodes in 2. Conclusions: Imaging with PET/CT provides superior diagnostic and staging information in patients with LABC compared with CI, which has significant therapeutic implications with respect to radiation therapy management. Imaging with PET/CT should be considered in all patients undergoing primary

  12. Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

    PubMed

    AlJaroudi, Wael A; Hage, Fadi G

    2016-02-01

    In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging.

  13. Review of cardiovascular imaging in the journal of nuclear cardiology in 2015. Part 1 of 2: Plaque imaging, positron emission tomography, computed tomography, and magnetic resonance.

    PubMed

    AlJaroudi, Wael A; Hage, Fadi G

    2016-02-01

    In 2015, many original articles pertaining to cardiovascular imaging with impressive quality were published in the Journal of Nuclear Cardiology. In a set of 2 articles, we provide an overview of these contributions to facilitate for the interested reader a quick review of the advancements that occurred in the field over this year. In this first article, we focus on arterial plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance imaging. PMID:26542991

  14. 18F-fluorodeoxyglucose positron emission tomography-computed tomography finding of left gonadal vein thrombosis in a case of renal cell carcinoma.

    PubMed

    Narayan, Ravishwar; Ravishankar, Uma; Natarajan, Savita; Vohra, Sandeep

    2016-01-01

    Tumor thrombus from renal cell carcinoma is commonly reported in renal vein and inferior vena cava with a few reports of gonadal vein involvement. Here, we report a case of an elderly female who underwent fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan for initial staging of left renal cell carcinoma. Along with an FDG avid left renal mass lesion, scan also revealed FDG avid tumor thrombus in the entire length of the left gonadal vein.

  15. Unilateral primary adrenal natural killer/T-cell lymphoma: Role of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography for staging and interim response assessment

    PubMed Central

    Kabnurkar, Rasika; Agrawal, Archi; Epari, Sridhar; Purandare, Nilendu; Shah, Sneha; Rangarajan, Venkatesh

    2016-01-01

    Primary adrenal lymphoma (PAL) is a rare malignancy often involving bilateral adrenal glands. Diffuse large B-cell is the most common histological type. Unilateral presentation and T-cell/natural killer (T/NK) cell histological type is rarer. We report fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography scan findings in a case of unilateral T/NK cell PAL performed for staging and interim treatment response assessment. PMID:26917897

  16. Persistence of cerebral metabolic abnormalities in chronic schizophrenia as determined by positron emission tomography

    SciTech Connect

    Wolkin, A.; Jaeger, J.; Brodie, J.D.; Wolf, A.P.; Fowler, J.; Rotrosen, J.; Gomez-Mont, F.; Cancro, R.

    1985-05-01

    Local cerebral metabolic rates were determined by positron emission tomography and the deoxyglucose method in a group of 10 chronic schizophrenic subjects before and after somatic treatment and in eight normal subjects. Before treatment, schizophrenic subjects had markedly lower absolute metabolic activity than did normal controls in both frontal and temporal regions and a trend toward relative hyperactivity in the basal ganglia area. After treatment, their metabolic rates approached those seen in normal subjects in nearly all regions except frontal. Persistence of diminished frontal metabolism was manifested as significant relative hypofrontality. These findings suggest specific loci of aberrant cerebral functioning in chronic schizophrenia and the utility of positron emission tomography in characterizing these abnormalities.

  17. 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.

  18. 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.

  19. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    SciTech Connect

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

  20. Imaging Enterobacteriaceae infection in vivo with 18F-fluorodeoxysorbitol positron emission tomography

    PubMed Central

    Weinstein, Edward A.; Ordonez, Alvaro A.; DeMarco, Vincent P.; Murawski, Allison M.; Pokkali, Supriya; MacDonald, Elizabeth M.; Klunk, Mariah; Mease, Ronnie C.; Pomper, Martin G.; Jain, Sanjay K.

    2015-01-01

    The Enterobacteriaceae are a family of rod-shaped Gram-negative bacteria that normally inhabit the gastrointestinal tract and are the most common cause of Gram-negative bacterial infections in humans. In addition to causing serious multidrug-resistant, hospital-acquired infections, a number of Enterobacteriaceae species are also recognized as biothreat pathogens. As a consequence, new tools are urgently needed to specifically identify and localize infections due to Enterobacteriaceae and to monitor antimicrobial efficacy. In this report, we used commercially available 2-[18F]-fluorodeoxyglucose (18F-FDG) to produce 2-[18F]-fluorodeoxysorbitol (18F-FDS), a radioactive probe for Enterobacteriaceae, in 30 min. 18F-FDS selectively accumulated in Enterobacteriaceae, but not in Gram-positive bacteria or healthy mammalian or cancer cells in vitro. In a murine myositis model, 18F-FDS positron emission tomography (PET) rapidly differentiated true infection from sterile inflammation with a limit of detection of 6.2 ± 0.2 log10 colony-forming units (CFU) for Escherichia coli. Our findings were extended to models of mixed Gram-positive and Gram-negative thigh co-infections, brain infection, Klebsiella pneumonia, and mice undergoing immunosuppressive chemotherapy. This technique rapidly and specifically localized infections due to Enterobacteriaceae, providing a three-dimensional holistic view within the animal. Last, 18F-FDS PET monitored the efficacy of antimicrobial treatment, demonstrating a PET signal proportionate to the bacterial burden. Therapeutic failures associated with multidrug-resistant, extended-spectrum β-lactamase (ESBL)–producing E. coli infections were detected in real time. Together, these data show that 18F-FDS is a candidate imaging probe for translation to human clinical cases of known or suspected infections owing to Enterobacteriaceae. PMID:25338757

  1. Positron emission tomography for initial staging of esophageal cancer among medicare beneficiaries

    PubMed Central

    Varghese, Thomas K.; Flanagan, Meghan R.; Flum, David R.; Shankaran, Veena; Oelschlager, Brant K.; Mulligan, Michael S.; Wood, Douglas E.; Pellegrini, Carlos A.

    2016-01-01

    Background The role of positron emission tomography (PET) in the initial staging of esophageal cancer is to detect occult metastases, but its ability to do so has not been evaluated at the population-level. In 2001, Medicare approved reimbursement of PET for esophageal cancer staging. We hypothesized rapid adoption of PET after 2001 and a coincident increase in the prevalence of stage IV disease. Methods A retrospective cohort study [1997-2009] was conducted of 12,870 Medicare beneficiaries with esophageal cancer using the Surveillance, Epidemiology, and End-Results (SEER)-Medicare database. Results PET use increased from <3% before 2001 to 44% in 2009 (post-PET era) (P trend <0.001). Over the same period, the prevalence of stage IV disease also increased (20% in 1997 and 28% in 2009, P trend <0.001). After adjusting for changing patient characteristics over time, the rate of increase in stage IV disease in the post-PET era [relative risk (RR) =1.06; 95% confidence interval (CI), 1.00-1.13] was no different than the rate of increase in the pre-PET era (RR =1.02; 95% CI, 1.02-1.04). Over the entire study period, the prevalence of unrecorded stage decreased by more than half (43% to 18%, adjusted P trend <0.001) with coincident increases in stage 0-III (37% to 53%, adjusted P trend <0.001) as well as stage IV disease. Conclusions The increasing frequency of PET use and stage IV disease over time is more likely explained by improved documentation rather than PET’s ability to detect occult metastases. The absence of compelling population-level impact compliments previous studies, revealing an opportunity to increase value through selective use of PET. PMID:27284472

  2. SensL B-Series and C-Series silicon photomultipliers for time-of-flight positron emission tomography

    NASA Astrophysics Data System (ADS)

    O`Neill, K.; Jackson, C.

    2015-07-01

    Silicon photomultipliers from SensL are designed for high performance, uniformity and low cost. They demonstrate peak photon detection efficiency of 41% at 420 nm, which is matched to the output spectrum of cerium doped lutetium orthosilicate. Coincidence resolving time of less than 220 ps is demonstrated. New process improvements have lead to the development of C-Series SiPM which reduces the dark noise by over an order of magnitude. In this paper we will show characterization test results which include photon detection efficiency, dark count rate, crosstalk probability, afterpulse probability and coincidence resolving time comparing B-Series to the newest pre-production C-Series. Additionally we will discuss the effect of silicon photomultiplier microcell size on coincidence resolving time allowing the optimal microcell size choice to be made for time of flight positron emission tomography systems.

  3. Brain dopamine metabolism in patients with Parkinson's disease measured with positron emission tomography.

    PubMed Central

    Leenders, K L; Palmer, A J; Quinn, N; Clark, J C; Firnau, G; Garnett, E S; Nahmias, C; Jones, T; Marsden, C D

    1986-01-01

    L-[18F] fluorodopa was administered in trace amounts intravenously to healthy control subjects and to patients with Parkinson's disease. Striatal uptake of radioactivity was measured using positron emission tomography. The capacity of the striatum to retain tracer was severely impaired in patients compared to controls. This may reflect a reduction of striatal dopamine storage in Parkinson's disease. Patients showing the "on/off" phenomenon had an even greater decrease of striatal storage capacity. Images PMID:3091770

  4. 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.

  5. Bimedial rectus hypermetabolism in convergence spasm as observed on positron emission tomography.

    PubMed

    Jeong, Seong-Hae; Oh, Young-Mi; Kim, Chae-Yong; Kim, Ji Soo

    2008-09-01

    A 52-year-old man developed vertical gaze palsy, convergence spasm, and convergence-retraction nystagmus due to glioblastoma of the right thalamus. 18F-fluorodeoxyglucose positron emission tomography (PET) inadvertently demonstrated markedly increased metabolism in the medial rectus muscles. The hypermetabolism indicates active contraction of these extraocular muscles due to excessive convergence drive attributed to inappropriate activation or disrupted inhibition of convergence neurons by the diencephalic lesion.

  6. Noninvasive measurement of regional myocardial glucose metabolism by positron emission computed tomography. [Dogs

    SciTech Connect

    Schelbert, H.R.; Phelps, M.E.

    1980-06-01

    While the results of regional myocardial glucose metabolism measurements using positron emission computed tomography (/sup 13/N-ammonia) are promising, their utility and value remains to be determined in man. If this technique can be applied to patients with acute myocardial ischemia or infarction it may permit delineation of regional myocardial segments with altered, yet still active metabolism. Further, it may become possible to evaluate the effects of interventions designed to salvage reversibly injured myocardium by this technique.

  7. A head motion measurement system suitable for emission computed tomography

    SciTech Connect

    Goldstein, S.R.; Eidsath, A.; Daube-Witherspoon, M.E.; Green, M.V.

    1997-02-01

    Subject motion during brain imaging studies can adversely affect the images through loss of resolution and other artifacts related to movement. The authors have developed and tested a device to measure heat motion externally in real-time during emission computed tomographic (ECT) brain imaging studies, to be used eventually to correct ECT data for that motion. The system is based on optical triangulation of three miniature lights affixed to the patient`s head and viewed by two position-sensitive detectors. The computer-controlled device converts the three sets of lamp positions into rotational and translational coordinates every 0.7 seconds. When compared against a mechanical test fixture, the optical system was found to be linear and accurate with minimal crosstalk between the coordinates. In a study of two subjects, comparing the angular motions measured by the optical device and a commercially available electromagnetic motion detector, the two systems agreed well, with an root mean square (rms) difference of less than 0.6{degree} for all rotations.

  8. Stable confinement of positron emission tomography and magnetic resonance agents within carbon nanotubes for bimodal imaging

    PubMed Central

    Cisneros, Brandon T; Law, Justin J; Matson, Michael L; Azhdarinia, Ali; Sevick-Muraca, Eva M; Wilson, Lon J

    2014-01-01

    Aims Simultaneous positron emission tomography/MRI has recently been introduced to the clinic and dual positron emission tomography/MRI probes are rare and of growing interest. We have developed a strategy for producing multimodal probes based on a carbon nanotube platform without the use of chelating ligands. Materials & methods Gd3+ and 64Cu2+ ions were loaded into ultra-short single-walled carbon nanotubes by sonication. Normal, tumor-free athymic nude mice were injected intravenously with the probe and imaged over 48 h. Results & conclusion The probe was stable for up to 24 h when challenged with phosphate-buffered saline and mouse serum. Positron emission tomography imaging also confirmed the stability of the probe in vivo for up to 48 h. The probe was quickly cleared from circulation, with enhanced accumulation in the lungs. Stable encapsulation of contrast agents within ultra-short single-walled carbon nanotubes represents a new strategy for the design of advanced imaging probes with variable multimodal imaging capabilities. PMID:24628687

  9. Positron Emission Tomography in Prostate Cancer: Summary of Systematic Reviews and Meta-Analysis

    PubMed Central

    Jadvar, Hossein

    2015-01-01

    Prostate cancer is a prevalent public health problem worldwide. Over the past decade, there has been tremendous research activity in the potential use of positron emission tomography with a number of radiotracers targeted to various biological aspects of this complex tumor. Systematic reviews and meta-analysis are important contributions to the relevant literature that summarize the evidence while reducing the effect of various sources of bias in the published data. The accumulation of relevant data in this clinical setting has recently provided the opportunity for systematic reviews. In this brief article, I summarize the published systematic reviews and meta-analysis of positron emission tomography in prostate cancer. Most robust evidence suggests a probable role for first-line use of positron emission tomography with radiolabeled choline in restating patients with biochemical relapse of prostate cancer with the diagnostic performance that appears to be positively associated with the serum prostate specific antigen level and velocity. Future systematic reviews will be needed for other emerging radiotracers such as those based on prostate specific membrane antigen and gastrin-releasing peptide receptor. PMID:26726317

  10. Targeted positron emission tomography imaging of CXCR4 expression in patients with acute myeloid leukemia

    PubMed Central

    Herhaus, Peter; Habringer, Stefan; Philipp-Abbrederis, Kathrin; Vag, Tibor; Gerngross, Carlos; Schottelius, Margret; Slotta-Huspenina, Julia; Steiger, Katja; Altmann, Torben; Weißer, Tanja; Steidle, Sabine; Schick, Markus; Jacobs, Laura; Slawska, Jolanta; Müller-Thomas, Catharina; Verbeek, Mareike; Subklewe, Marion; Peschel, Christian; Wester, Hans-Jürgen; Schwaiger, Markus; Götze, Katharina; Keller, Ulrich

    2016-01-01

    Acute myeloid leukemia originates from leukemia-initiating cells that reside in the protective bone marrow niche. CXCR4/CXCL12 interaction is crucially involved in recruitment and retention of leukemia-initiating cells within this niche. Various drugs targeting this pathway have entered clinical trials. To evaluate CXCR4 imaging in acute myeloid leukemia, we first tested CXCR4 expression in patient-derived primary blasts. Flow cytometry revealed that high blast counts in patients with acute myeloid leukemia correlate with high CXCR4 expression. The wide range of CXCR4 surface expression in patients was reflected in cell lines of acute myeloid leukemia. Next, we evaluated the CXCR4-specific peptide Pentixafor by positron emission tomography imaging in mice harboring CXCR4 positive and CXCR4 negative leukemia xenografts, and in 10 patients with active disease. [68Ga]Pentixafor-positron emission tomography showed specific measurable disease in murine CXCR4 positive xenografts, but not when CXCR4 was knocked out with CRISPR/Cas9 gene editing. Five of 10 patients showed tracer uptake correlating well with leukemia infiltration assessed by magnetic resonance imaging. The mean maximal standard uptake value was significantly higher in visually CXCR4 positive patients compared to CXCR4 negative patients. In summary, in vivo molecular CXCR4 imaging by means of positron emission tomography is feasible in acute myeloid leukemia. These data provide a framework for future diagnostic and theranostic approaches targeting the CXCR4/CXCL12-defined leukemia-initiating cell niche. PMID:27175029

  11. 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.

  12. Contribution of 3-D electrical resistivity tomography for landmines detection

    NASA Astrophysics Data System (ADS)

    Metwaly, M.; El-Qady, G.; Matsushima, J.; Szalai, S.; Al-Arifi, N. S. N.; Taha, A.

    2008-12-01

    Landmines are a type of inexpensive weapons widely used in the pre-conflicted areas in many countries worldwide. The two main types are the metallic and non-metallic (mostly plastic) landmines. They are most commonly investigated by magnetic, ground penetrating radar (GPR), and metal detector (MD) techniques. These geophysical techniques however have significant limitations in resolving the non-metallic landmines and wherever the host materials are conductive. In this work, the 3-D electric resistivity tomography (ERT) technique is evaluated as an alternative and/or confirmation detection system for both landmine types, which are buried in different soil conditions and at different depths. This can be achieved using the capacitive resistivity imaging system, which does not need direct contact with the ground surface. Synthetic models for each case have been introduced using metallic and non-metallic bodies buried in wet and dry environments. The inversion results using the L1 norm least-squares optimization method tend to produce robust blocky models of the landmine body. The dipole axial and the dipole equatorial arrays tend to have the most favorable geometry by applying dynamic capacitive electrode and they show significant signal strength for data sets with up to 5% noise. Increasing the burial depth relative to the electrode spacing as well as the noise percentage in the resistivity data is crucial in resolving the landmines at different environments. The landmine with dimension and burial depth of one electrode separation unit is over estimated while the spatial resolutions decrease as the burial depth and noise percentage increase.

  13. High-fidelity state detection and tomography of a single-ion Zeeman qubit

    NASA Astrophysics Data System (ADS)

    Keselman, A.; Glickman, Y.; Akerman, N.; Kotler, S.; Ozeri, R.

    2011-07-01

    We demonstrate high-fidelity Zeeman qubit state detection in a single trapped 88Sr+ ion. Qubit readout is performed by shelving one of the qubit states to a metastable level using a narrow linewidth diode laser at 674 nm, followed by state-selective fluorescence detection. The average fidelity reached for the readout of the qubit state is 0.9989(1). We then measure the fidelity of state tomography, averaged over all possible single-qubit states, which is 0.9979(2). We also fully characterize the detection process using quantum process tomography. This readout fidelity is compatible with recent estimates of the detection error threshold required for fault-tolerant computation, whereas high-fidelity state tomography opens the way for high-precision quantum process tomography.

  14. Influence of slice overlap on positron emission tomography image quality

    NASA Astrophysics Data System (ADS)

    McKeown, Clare; Gillen, Gerry; Dempsey, Mary Frances; Findlay, Caroline

    2016-02-01

    PET scans use overlapping acquisition beds to correct for reduced sensitivity at bed edges. The optimum overlap size for the General Electric (GE) Discovery 690 has not been established. This study assesses how image quality is affected by slice overlap. Efficacy of 23% overlaps (recommended by GE) and 49% overlaps (maximum possible overlap) were specifically assessed. European Association of Nuclear Medicine (EANM) guidelines for calculating minimum injected activities based on overlap size were also reviewed. A uniform flood phantom was used to assess noise (coefficient of variation, (COV)) and voxel accuracy (activity concentrations, Bq ml-1). A NEMA (National Electrical Manufacturers Association) body phantom with hot/cold spheres in a background activity was used to assess contrast recovery coefficients (CRCs) and signal to noise ratios (SNR). Different overlap sizes and sphere-to-background ratios were assessed. COVs for 49% and 23% overlaps were 9% and 13% respectively. This increased noise was difficult to visualise on the 23% overlap images. Mean voxel activity concentrations were not affected by overlap size. No clinically significant differences in CRCs were observed. However, visibility and SNR of small, low contrast spheres (⩽13 mm diameter, 2:1 sphere to background ratio) may be affected by overlap size in low count studies if they are located in the overlap area. There was minimal detectable influence on image quality in terms of noise, mean activity concentrations or mean CRCs when comparing 23% overlap with 49% overlap. Detectability of small, low contrast lesions may be affected in low count studies—however, this is a worst-case scenario. The marginal benefits of increasing overlap from 23% to 49% are likely to be offset by increased patient scan times. A 23% overlap is therefore appropriate for clinical use. An amendment to EANM guidelines for calculating injected activities is also proposed which better reflects the effect overlap size has

  15. Contrast-enhanced [18 F] fluorodeoxyglucose-positron emission tomography/computed tomography in clinical oncology: tumor-, site-, and question-based comparison with standard positron emission tomography/computed tomography

    PubMed Central

    2014-01-01

    Background The present study aimed to evaluate the added value of contrast-enhanced computed tomography (ceCT) in comparison to standard, non-enhanced CT in the context of a combined positron emission tomography (PET)/CT examination by means of a tumor-, site-, and clinical question-based approach. Methods Analysis was performed in 202 patients undergoing PET/CT consisting of a multiphase CT protocol followed by a whole-body PET. The Cochran Q test was performed, followed by a multiple comparisons correction (McNemar test and Bonferroni adjustment), to compare standard and contrast-enhanced PET (cePET/CT). Histopathology or clinical-radiologic follow-up greater than 1 year was used as a reference. Results cePET/CT showed significantly different results with respect to standard PET/CT in head and neck and gastrointestinal cancer (P = 0.02 and 0.0002, respectively), in the evaluation of lesions located in the abdomen (P = 0.009), and in the context of disease restaging (P = 0.003). In all these clinical scenarios, adding ceCT resulted in a distinct benefit, by yielding a higher percentage of change in patient management. Conclusion These data strongly underline the importance of strictly selecting patients for the combined exam. In particular, patient selection should not be driven solely by mere tumor classification, but should also account for the clinical question and the anatomical location of the neoplastic disease, which can significantly impact patient management. PMID:25609564

  16. Design and development of a dedicated mammary and axillary region positron emission tomography system

    NASA Astrophysics Data System (ADS)

    Doshi, Niraj Kumar

    Breast cancer is the second leading cause of cancer death in women. Currently, mammography and physical breast examination, both non-invasive techniques, provide the two most effective methods available for screening potential breast cancer patients. During the management of patients, however, several invasive techniques such as axillary lymph node dissection, core biopsies and lumpectomies, are utilized to determine the stage or malignancy of the disease with significant cost and morbidity associated with them. Positron Emission Tomography (PET), using [F-18] fluorodeoxyglucose (FDG) tracer is a sensitive and non-invasive imaging modality that may be a cost-effective alternative to certain invasive procedures. In this project we have developed a low cost, high performance, dedicated PET camera (maxPET) for mammary and axillary region imaging. The system consists of two 15x15 cm2 planar scintillation detector arrays composed of modular detectors operating in coincidence. The modular detectors are comprised of a 9x9 array of 3x3x20 mm3 lutetiurn oxyorthosilicate (LSO) detector elements, read out by a 5x5 array of position- sensitive photomultiplier tubes. The average measured intrinsic spatial resolution of a detector module is 2.26 mm with a sensitivity of up to 40% for a central point source. The measured coincidence timing resolution for two modules is 2.4 ns. The average energy resolution measured across the entire two detector plates is 21.6%. The coincidence timing resolution for the entire system is 8.1 ns. A line bar phantom was imaged and images were reconstructed using the focal plane tomography algorithm. A 4 mm projection image resolution was measured based on profiles taken through the line bar phantom images. The goal of the maxPET system will be to aid in breast cancer patient management by assisting in imaging women with dense, fibro-glandular breasts, detecting axillary lymph node metastases without surgery, monitoring chemotherapy effectiveness and

  17. A novel image reconstruction methodology based on inverse Monte Carlo analysis for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Kudrolli, Haris A.

    2001-04-01

    A three dimensional (3D) reconstruction procedure for Positron Emission Tomography (PET) based on inverse Monte Carlo analysis is presented. PET is a medical imaging modality which employs a positron emitting radio-tracer to give functional images of an organ's metabolic activity. This makes PET an invaluable tool in the detection of cancer and for in-vivo biochemical measurements. There are a number of analytical and iterative algorithms for image reconstruction of PET data. Analytical algorithms are computationally fast, but the assumptions intrinsic in the line integral model limit their accuracy. Iterative algorithms can apply accurate models for reconstruction and give improvements in image quality, but at an increased computational cost. These algorithms require the explicit calculation of the system response matrix, which may not be easy to calculate. This matrix gives the probability that a photon emitted from a certain source element will be detected in a particular detector line of response. The ``Three Dimensional Stochastic Sampling'' (SS3D) procedure implements iterative algorithms in a manner that does not require the explicit calculation of the system response matrix. It uses Monte Carlo techniques to simulate the process of photon emission from a source distribution and interaction with the detector. This technique has the advantage of being able to model complex detector systems and also take into account the physics of gamma ray interaction within the source and detector systems, which leads to an accurate image estimate. A series of simulation studies was conducted to validate the method using the Maximum Likelihood - Expectation Maximization (ML-EM) algorithm. The accuracy of the reconstructed images was improved by using an algorithm that required a priori knowledge of the source distribution. Means to reduce the computational time for reconstruction were explored by using parallel processors and algorithms that had faster convergence rates

  18. Impact of Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and Positron Emission Tomography/Computed Tomography (PET/CT) in the Diagnosis of Traumatic Brain Injury (TBI): Case Report.

    PubMed

    Molina-Vicenty, Irma L; Santiago-Sánchez, Michelaldemar; Vélez-Miró, Iván; Motta-Valencia, Keryl

    2016-09-01

    Traumatic brain injury (TBI) is defined as damage to the brain resulting from an external force. TBI, a global leading cause of death and disability, is associated with serious social, economic, and health problems. In cases of mild-to-moderate brain damage, conventional anatomical imaging modalities may or may not detect the cascade of metabolic changes that have occurred or are occurring at the intracellular level. Functional nuclear medicine imaging and neurophysiological parameters can be used to characterize brain damage, as the former provides direct visualization of brain function, even in the absence of overt behavioral manifestations or anatomical findings. We report the case of a 30-year-old Hispanic male veteran who, after 2 traumatic brain injury events, developed cognitive and neuropsychological problems with no clear etiology in the presence of negative computed tomography (CT) findings. PMID:27623144

  19. Comparison of Physical Examination and Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography 4-6 Months After Radiotherapy to Assess Residual Head-and-Neck Cancer

    SciTech Connect

    Zundel, M. Tracy; Michel, Michelle A.; Schultz, Christopher J.; Maheshwari, Mohit; Wong, Stuart J.; Campbell, Bruce H.; Massey, Becky L.; Blumin, Joel; Wilson, J. Frank; Wang, Dian

    2011-12-01

    Purpose: To retrospectively compare fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and physical examination 4-6 months after radiotherapy for assessing residual head-and-neck cancer (HNC). Methods and Materials: From July 2002 through March 2006, 52 HNC patients underwent definitive radiotherapy or chemoradiotherapy. Categoric assessments of residual tumor by PET/CT and physical examination 4-6 months after therapy were correlated and compared with clinical outcomes. Pretreatment data, including tumor stage and primary site standardized uptake value, were also gathered retrospectively and correlated with clinical outcomes. Median follow-up time was 58 months. Results: Twenty-one patients had either locoregionally 'positive' (17 of 21) or 'equivocal' (4 of 21) PET/CT scans, whereas 31 patients had locoregionally negative scans. Four patients failed treatment and had biopsy-confirmed residual or recurrent local disease. All patients, including patients with locally suspicious scans or examinations who refused biopsies, were followed clinically for a minimum of 29 months after therapy, with no other cases of treatment failure detected during this time. No patient had residual nodal disease after therapy. Sensitivities of PET/CT vs. physical examination for early detection of treatment failure were 100% vs. 50%, whereas the specificities of the two modalities were 64.6% vs. 89.6%, respectively. Higher initial T stage and American Joint Commission on Cancer stage correlated with increased incidence of positive/equivocal PET/CT results and treatment failure. Maximal standardized uptake value was not predictive of any clinical outcome. Conclusions: A negative result on PET/CT obtained 4-6 months after radiotherapy is highly sensitive and correlates with successful locoregional control. Patients with negative scans may reasonably be spared invasive diagnostic procedures, such as biopsy and neck dissection, unless recurrent disease is suspected

  20. Positron Emission Tomography (PET): Towards Time of Flight

    SciTech Connect

    Karp, Joel

    2004-09-29

    PET is a powerful imaging tool that is being used to study cancer, using a variety of tracers to measure physiological processes including glucose metabolism, cell proliferation, and hypoxia in tumor cells. As the utilization of PET has grown in the last several years, it has become clear that improved lesion detection and quantification are critical goals for cancer studies. Although physical performance of the current generation of PET scanners has improved recently, there are limitations especially for heavy patients where attenuation and scatter effects are increased. We are investigating new scintillation detectors, scanner designs, and image processing algorithms in order to overcome these limitations and improve performance. In particular, we are studying scanner designs that would incorporate scintillators with improved energy and timing resolution. Improved energy resolution helps to reduce scattered radiation, and improved timing resolution makes it feasible to incorporate the time-of-flight information between the two coincident gamma rays into the image reconstruction algorithm, a technique that improves signal-to-noise. Results of recent experiments and computer simulations will be shown to demonstrate these potential improvements.

  1. Pharmacologic stress dual-isotope myocardial perfusion single-photon emission computed tomography.

    PubMed

    Matzer, L; Kiat, H; Wang, F P; Van Train, K; Germano, G; Friedman, J; Berman, D S

    1994-12-01

    Separate-acquisition rest thallium-201/exercise technetium-99m sestamibi (sestamibi) dual-isotope single-photon emission computed tomography (SPECT) has been shown to be effective for assessment of myocardial perfusion and viability. The present study was designed to validate the dual-isotope approach when used in conjunction with pharmacologic stress. All patients had rest 201TI SPECT followed immediately by adenosine (n = 82) or dipyridamole (n = 50) infusion and sestamibi injection. Sestamibi SPECT was performed 1 hour later. The entire study lasted < 2.5 hours. The patient population was categorized into three groups: 51 consecutive patients with coronary angiography and no previous myocardial infarction (group I), 58 consecutive patients with a low prescintigraphic test likelihood of coronary artery disease (group II), and 23 consecutive catheterized patients with remote Q-wave myocardial infarction (group III). For group I patients, the sensitivity and specificity for dual-isotope SPECT were 92% (35 of 38) and 85% (11 of 13), respectively, when > or = 50% coronary artery narrowing was considered significant and were 97% (34 of 35) and 81% (13 of 16) respectively, when > or = 70% narrowing was considered significant. The normalcy rate among the 58 patients of group II was 96%. Comparisons for pattern of stress-defect reversibility demonstrated that of the 97 stress defects within the infarct zones (group III), 15% were reversible and 85% were nonreversible. In contrast, of the 227 stress defects within the diseased (> or = 50% stenosis) vessel zones of the group I patients, 93% were reversible and 7% were noreversible (p < 0.001 vs group III). In conclusion, separate acquisition rest 201-TI/pharmacologic stress sestamibi dual-isotope SPECT is an efficient myocardial perfusion imaging protocol with high accuracy for detection and assessment of angiographically significant coronary artery disease.

  2. Molecular imaging of atherosclerotic lesions by positron emission tomography - can it meet the expectations?

    PubMed

    Brammen, Lindsay; Steiner, Sabine; Berent, Robert; Sinzinger, Helmut

    2016-01-01

    Early non-invasive imaging of atherosclerosis and in particular the detection of lesions at risk with high specificity could significantly affect cardiovascular morbidity and mortality. Conventional nuclear medicine approaches, in particular using autologous radiolabeled lipoproteins, can be related to histopathological findings; however, they fail to identify lesions at risk. Positron emission tomography (PET) tracers with much better physical properties have been examined, the most detailed information being available for F-18-deoxyglucose (FDG) and F-18-sodium fluoride (NaF). These two approaches are sensitive to different biochemical mechanisms, i.e. inflammation and microcalcification. Initial enthusiasm, in particular for F-18-FDG, has disappeared, although for F-18-NaF there is some hope, but this is not a breakthrough. No tracer is available so far that is able to identify a specific characteristic of a lesion prone to rupture. Other PET tracers in the pipeline have been examined, mainly in experimental models and only a few in patients, but they failed to contribute significantly to early lesion discovery and do not support great expectations. The key question is: Do we understand what we see? Moreover, methodological problems, a lack of standardization of imaging protocols and aspects of quantification provide a wide range for potential future improvements. While monitoring a therapeutic intervention seems to be possible for both F-18-FDG and F-18-NaF, highly specific early identification of lesions at risk by PET imaging is still far away. As of today, PET is not ready for routine clinical judgment of atherosclerotic lesions at risk to rupture. Even if all these problems can be solved, radiation exposure will still remain a concern, in particular for repeated studies.

  3. Molecular imaging of atherosclerotic lesions by positron emission tomography - can it meet the expectations?

    PubMed

    Brammen, Lindsay; Steiner, Sabine; Berent, Robert; Sinzinger, Helmut

    2016-01-01

    Early non-invasive imaging of atherosclerosis and in particular the detection of lesions at risk with high specificity could significantly affect cardiovascular morbidity and mortality. Conventional nuclear medicine approaches, in particular using autologous radiolabeled lipoproteins, can be related to histopathological findings; however, they fail to identify lesions at risk. Positron emission tomography (PET) tracers with much better physical properties have been examined, the most detailed information being available for F-18-deoxyglucose (FDG) and F-18-sodium fluoride (NaF). These two approaches are sensitive to different biochemical mechanisms, i.e. inflammation and microcalcification. Initial enthusiasm, in particular for F-18-FDG, has disappeared, although for F-18-NaF there is some hope, but this is not a breakthrough. No tracer is available so far that is able to identify a specific characteristic of a lesion prone to rupture. Other PET tracers in the pipeline have been examined, mainly in experimental models and only a few in patients, but they failed to contribute significantly to early lesion discovery and do not support great expectations. The key question is: Do we understand what we see? Moreover, methodological problems, a lack of standardization of imaging protocols and aspects of quantification provide a wide range for potential future improvements. While monitoring a therapeutic intervention seems to be possible for both F-18-FDG and F-18-NaF, highly specific early identification of lesions at risk by PET imaging is still far away. As of today, PET is not ready for routine clinical judgment of atherosclerotic lesions at risk to rupture. Even if all these problems can be solved, radiation exposure will still remain a concern, in particular for repeated studies. PMID:27058798

  4. Evaluation of Shoulder Disorders by 2-[F-18]-fluoro-2-deoxy-D-glucose Positron Emission Tomography and Computed Tomography

    PubMed Central

    Lee, Sang Hong; Park, Sung Yong; Yu, Jae Cheol; Gorthi, Venkat

    2010-01-01

    Background Although flourine-18-flourodeoxyglucose (FDG) positron emission tomography (PET) has a limitation for localizing anatomical structures, combining it with computed tomography (CT) has made it more efficient for overcoming such limitations. This study aims to evaluate the efficacy of PET/CT for evaluating diseases of the shoulder. Methods Retrospective examination was performed on 25 patients who underwent FDG-PET/CT scanning. All the patients were over 60 years of age, and they were evaluated both clinically and radiologically for shoulder pain. The study period was from May, 2006 to May, 2008. One of the patients had metastatic lesion in a shoulder and this patient was excluded from the study, so the total number of subjects in the study was finally 24 patients. Results PET/CT showed 67% sensitivity, 73% specificity, a positive predictive value of 60%, a negative predictive value of 79%, 27% false positivity and 33% false negativity concerning shoulder pain. PET/CT showed negative finding in 4 cases that were successfully treated by operative treatment (rotator cuff tear [RCT], 3 cases; impingement syndrome, 1 case). Negative findings were also noted in 6 cases in which the pain subsided after conservative treatment (RCT, 1 case; suspected RCT, 2 cases; impingement syndrome, 3 cases). All the patients with osteoarthritis and rheumatoid arthritis had positive findings on PET/CT scanning. Conclusions PET/CT is a useful adjunct to the existing imaging modalities to assess functional and pathophysiologic processes and at a very early stage, and so PET/CT can help physicians make better preoperative and postoperative decisions on treatment. PMID:20808588

  5. Determination of Internal Target Volume From a Single Positron Emission Tomography/Computed Tomography Scan in Lung Cancer

    SciTech Connect

    Chang Guoping; Chang Tingting; Pan Tinsu; Clark, John W.; Mawlawi, Osama R.

    2012-05-01

    Purpose: The use of four-dimensional computed tomography (4D-CT) to determine the tumor internal target volume (ITV) is usually characterized by high patient radiation exposure. The objective of this study was to propose and evaluate an approach that relies on a single static positron emission tomography (PET)/CT scan to determine the ITV, thereby eliminating the need for 4D-CT and thus reduce patient radiation dose. Methods and Materials: The proposed approach is based on the concept that the observed PET image is the result of a joint convolution of an ideal PET image (free from motion and partial volume effect) with a motion-blurring kernel (MBK) and partial volume effect. In this regard, the MBK and tumor ITV are then estimated from the deconvolution of this joint model. To test this technique, phantom and patient studies were performed using different sphere/tumor sizes and motion trajectories. In all studies, a 4D-CT and a PET/CT image of the sphere/tumor were acquired. The ITV from the proposed technique was then compared to the maximum intensity projection (MIP) volume of the 4D-CT images. A Dice coefficient of the two volumes was calculated to represent the similarity between the two ITVs. Results: The average ITVs of the proposed technique were 97.2% {+-} 0.3% and 81.0% {+-} 16.7% similar to the MIP volume in the phantom and patient studies, respectively. The average dice coefficients were 0.87 {+-} 0.05 and 0.73 {+-} 0.16, respectively, for the two studies. Conclusion: Using the proposed approach, a single static PET/CT scan has the potential to replace a 4D-CT to determine the tumor ITV. This approach has the added advantage of reducing patient radiation exposure and determining the tumor MBK compared to 4D-CT/MIP-CT.

  6. 18F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

    PubMed Central

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-01-01

    AIM To compare 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent 18F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ2 test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma. PMID:27678362

  7. Improving 18F-Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography Imaging in Alzheimer's Disease Studies

    PubMed Central

    Knešaurek, Karin

    2015-01-01

    The goal was to improve Alzheimer's 2-deoxy-2-18F-fluoro-D-glucose (18F FDG)-positron emission tomography (PET)/computed tomography (CT) imaging through application of a novel, hybrid Fourier-wavelet windowed Fourier transform (WFT) restoration technique, in order to provide earlier and more accurate clinical results. General Electric Medical Systems downward-looking sonar PET/CT 16 slice system was used to acquire studies. Patient data were acquired according the Alzheimer's disease Neuroimaging Initiative (ADNI) protocol. Here, we implemented Fourier-wavelet regularized restoration, with a Butterworth low-pass filter, order n = 6 and a cut-off frequency f = 0.35 cycles/pixel and wavelet (Daubechies, order 2) noise suppression. The original (PET-O) and restored (PET-R) ADNI subject PET images were compared using the Alzheimer's discrimination analysis by dedicated software. Forty-two PET/CT scans were used in the study. They were performed on eleven ADNI subjects at intervals of approximately 6 months. The final clinical diagnosis was used as a gold standard. For three subjects, the final clinical diagnosis was mild cognitive impairment and those 13 PET/CT studies were not included in the final comparison, as the result was considered as inconclusive. Using the reminding 29 PET/CT studies (23 AD and 6 normal), the sensitivity and specificity of the PET-O and PET-R were calculated. The sensitivity was 0.65 and 0.96 for PET-O and PET-R, respectively, and the specificity was 0.67 and 0.50 for PET-O and PET-R. The accuracy was 0.66 and 0.86 for PET-O and PET-R, respectively. The results of the study demonstrated that the accuracy of three-dimensional brain F-18 FDG PET images was significantly improved by Fourier-wavelet restoration filtering. PMID:26420987

  8. Improving (18)F-Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography Imaging in Alzheimer's Disease Studies.

    PubMed

    Knešaurek, Karin

    2015-01-01

    The goal was to improve Alzheimer's 2-deoxy-2-(18)F-fluoro-D-glucose ((18)F FDG)-positron emission tomography (PET)/computed tomography (CT) imaging through application of a novel, hybrid Fourier-wavelet windowed Fourier transform (WFT) restoration technique, in order to provide earlier and more accurate clinical results. General Electric Medical Systems downward-looking sonar PET/CT 16 slice system was used to acquire studies. Patient data were acquired according the Alzheimer's disease Neuroimaging Initiative (ADNI) protocol. Here, we implemented Fourier-wavelet regularized restoration, with a Butterworth low-pass filter, order n = 6 and a cut-off frequency f = 0.35 cycles/pixel and wavelet (Daubechies, order 2) noise suppression. The original (PET-O) and restored (PET-R) ADNI subject PET images were compared using the Alzheimer's discrimination analysis by dedicated software. Forty-two PET/CT scans were used in the study. They were performed on eleven ADNI subjects at intervals of approximately 6 months. The final clinical diagnosis was used as a gold standard. For three subjects, the final clinical diagnosis was mild cognitive impairment and those 13 PET/CT studies were not included in the final comparison, as the result was considered as inconclusive. Using the reminding 29 PET/CT studies (23 AD and 6 normal), the sensitivity and specificity of the PET-O and PET-R were calculated. The sensitivity was 0.65 and 0.96 for PET-O and PET-R, respectively, and the specificity was 0.67 and 0.50 for PET-O and PET-R. The accuracy was 0.66 and 0.86 for PET-O and PET-R, respectively. The results of the study demonstrated that the accuracy of three-dimensional brain F-18 FDG PET images was significantly improved by Fourier-wavelet restoration filtering.

  9. 18F-fluorodeoxyglucose positron emission tomography/computed tomography comparison of gastric lymphoma and gastric carcinoma

    PubMed Central

    Li, Xiao-Feng; Fu, Qiang; Dong, You-Wen; Liu, Jian-Jing; Song, Xiu-Yu; Dai, Dong; Zuo, Cong; Xu, Wen-Gui

    2016-01-01

    AIM To compare 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features in gastric lymphoma and gastric carcinoma. METHODS Patients with newly diagnosed gastric lymphoma or gastric carcinoma who underwent 18F-FDG PET/CT prior to treatment were included in this study. We reviewed and analyzed the PET/CT features of gastric wall lesions, including FDG avidity, pattern (focal/diffuse), and intensity [maximal standard uptake value: (SUVmax)]. The correlation of SUVmax with gastric clinicopathological variables was investigated by χ2 test, and receiver-operating characteristic (ROC) curve analysis was performed to determine the differential diagnostic value of SUVmax-associated parameters in gastric lymphoma and gastric carcinoma. RESULTS Fifty-two patients with gastric lymphoma and 73 with gastric carcinoma were included in this study. Abnormal gastric FDG accumulation was found in 49 patients (94.23%) with gastric lymphoma and 65 patients (89.04%) with gastric carcinoma. Gastric lymphoma patients predominantly presented with type I and type II lesions, whereas gastric carcinoma patients mainly had type III lesions. The SUVmax (13.39 ± 9.24 vs 8.35 ± 5.80, P < 0.001) and SUVmax/THKmax (maximal thickness) (7.96 ± 4.02 vs 4.88 ± 3.32, P < 0.001) were both higher in patients with gastric lymphoma compared with gastric carcinoma. ROC curve analysis suggested a better performance of SUVmax/THKmax in the evaluation of gastric lesions between gastric lymphoma and gastric carcinoma in comparison with that of SUVmax alone. CONCLUSION PET/CT features differ between gastric lymphoma and carcinoma, which can improve PET/CT evaluation of gastric wall lesions and help differentiate gastric lymphoma from gastric carcinoma.

  10. Radiation Dose from Whole-Body F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Nationwide Survey in Korea

    PubMed Central

    2016-01-01

    The purpose of this study was to estimate average radiation exposure from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) examinations and to analyze possible factors affecting the radiation dose. A nation-wide questionnaire survey was conducted involving all institutions that operate PET/CT scanners in Korea. From the response, radiation doses from injected FDG and CT examination were calculated. A total of 105 PET/CT scanners in 73 institutions were included in the analysis (response rate of 62.4%). The average FDG injected activity was 310 ± 77 MBq and 5.11 ± 1.19 MBq/kg. The average effective dose from FDG was estimated to be 5.89 ± 1.46 mSv. The average CT dose index and dose-length product were 4.60 ± 2.47 mGy and 429.2 ± 227.6 mGy∙cm, which corresponded to 6.26 ± 3.06 mSv. The radiation doses from FDG and CT were significantly lower in case of newer scanners than older ones (P < 0.001). Advanced PET technologies such as time-of-flight acquisition and point-spread function recovery were also related to low radiation dose (P < 0.001). In conclusion, the average radiation dose from FDG PET/CT is estimated to be 12.2 mSv. The radiation dose from FDG PET/CT is reduced with more recent scanners equipped with image-enhancing algorithms. PMID:26908992

  11. Positron emission tomography for measurement of copper fluxes in live organisms.

    PubMed

    Peng, Fangyu

    2014-05-01

    Copper is an essential nutrient for the physiology of live organisms, but excessive copper can be harmful. Copper radioisotopes are used for measurement of copper fluxes in live organisms using a radioactivity assay of body fluids or whole-body positron emission tomography (PET). Hybrid positron emission tomography-computed tomography (PET/CT) is a versatile tool for real-time measurement of copper fluxes combining the high sensitivity and quantification capability of PET and the superior spatial resolution of CT for anatomic localization of radioactive tracer activity. Kinetic analysis of copper metabolism in the liver and extrahepatic tissues of Atp7b(-/-) knockout mice, a mouse model of Wilson's disease, demonstrated the feasibility of measuring copper fluxes in live organisms with PET/CT using copper-64 chloride ((64) CuCl2 ) as a radioactive tracer ((64) CuCl2 -PET/CT). (64) CuCl2 -PET/CT holds potential as a useful tool for the diagnosis of inherited and acquired human copper metabolism disorders and for monitoring the effects of copper-modulating therapy.

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

    PubMed

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

    1999-12-01

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

  13. Positron Emission Tomography/Computed Tomography in the Staging and Treatment of Anal Cancer

    SciTech Connect

    Sveistrup, Joen; Loft, Annika; Berthelsen, Anne Kiil; Henriksen, Birthe Merete; Nielsen, Michael Bachmann; Engelholm, Svend Aage

    2012-05-01

    Purpose: This study was intended to determine the role of PET/CT in the staging of anal cancer as a supplement to three-dimensional transanal ultrasound (TAUS) and inguinal ultrasound (US). The impact of the PET/CT on the initial stage and treatment plan proposed by TAUS/US was assessed. Methods and Materials: Ninety-five (95) patients referred to our clinic between July 1, 2005, and December 31, 2009, were retrospectively reviewed. All patients had biopsy-proven primary squamous cell cancer of the anal canal. There were 65 females (68%) and 30 males (32%), and the median age was 58 years (range, 35-88 years). Six (6%) of the patients were HIV positive. All patients were staged with TAUS/US and PET/CT. Results: Twenty-eight (28) patients were diagnosed with suspicious perirectal node metastases. TAUS visualized 24 of these, whereas PET/CT detected 15. Suspicious inguinal nodes were visualized on either US or PET/CT in 41 patients. Seventeen (17) of these had confirmed malignant disease on biopsy, and 15 had confirmed benign disease. All 17 patients (100%) with malignant inguinal nodes were diagnosed by PET/CT, whereas US identified 16 (94%). Ten patients were diagnosed with suspicious inguinal nodes on PET/CT that had not been seen on US. One of these was malignant, three were benign, and six were not biopsied. PET/CT diagnosed eight metastatic sites, whereas TAUS/US diagnosed three. PET/CT discovered three of the five synchronous cancers seen in this study. PET/CT upstaged the disease in 14% of the cases and changed the treatment plan proposed by TAUS/US in 17%. Conclusion: PET/CT has great potential influence on the staging and treatment of anal cancer. TAUS is important in the staging of the primary tumor and N1-stage, whereas PET/CT seems necessary for the N2/3-stage, the M-stage and synchronous cancers.

  14. Brain energy metabolism and dopaminergic function in Huntington's disease measured in vivo using positron emission tomography

    SciTech Connect

    Leenders, K.L.; Frackowiak, R.S.; Quinn, N.; Marsden, C.D.

    1986-01-01

    A 48-year-old man with typical Huntington's disease was investigated with computed tomography (CT) and positron emission tomography. Regional cerebral blood flow, oxygen extraction, oxygen and glucose utilization, L-Dopa uptake, and dopamine (D2) receptor binding were measured using several positron-labelled tracers. CT showed slight atrophy of the head of caudate but no cortical atrophy, although distinct frontal lobe dysfunction was present on psychometric testing. Oxygen and glucose metabolism and cerebral blood flow were decreased in the striata and to a lesser extent in frontal cortex. Cerebral blood flow was in the low normal range throughout the remainder of the brain. A normal metabolic ratio was found in all regions, since the changes in glucose utilization paralleled those in oxygen consumption. The capacity of the striatum to store dopamine as assessed by L-( YF)-fluorodopa uptake was normal, but dopamine (D2) receptor binding was decreased when compared to normal subjects.

  15. 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.

  16. Hemiballismus: Study of a case using positron emission tomography with 18fluoro-2-deoxyglucose

    SciTech Connect

    Dubinsky, R.M.; Greenberg, M.; Di Chiro, G.; Baker, M.; Hallett, M. )

    1989-01-01

    A 64-year-old man had right-sided persistent hemiballismus. Cerebral computed tomography (CT) and 0.5-T magnetic resonance imaging (MRI) showed no abnormalities, but 1.5-T MRI showed decreased signal intensity of the putamina, greater on the left than on the right. The subthalamic area was normal on CT and MRI. Positron emission tomography with 18fluoro2-deoxyglucose showed marked hypometabolism of the left putamen (60% of the right) and hypermetabolism of the left parietal lobe (138% of the right). The decreased metabolism of the left putamen may indicate a reduction in neuronal firing. The pathophysiology of the hemiballismus in this case may be loss of tonic inhibition of the lateral globus pallidus from the putamen, leading in turn to greater inhibition of the subthalamic nucleus, less excitation of the medial globus pallidus, and less inhibition of the thalamus and motor cortex, and thus allowing expression of the ballistic movements.

  17. Use of 18F-2-Fluorodeoxyglucose to Label Antibody Fragments for Immuno-Positron Emission Tomography of Pancreatic Cancer

    PubMed Central

    2015-01-01

    We generated 18F-labeled antibody fragments for positron emission tomography (PET) imaging using a sortase-mediated reaction to install a trans-cyclooctene-functionalized short peptide onto proteins of interest, followed by reaction with a tetrazine-labeled-18F-2-deoxyfluoroglucose (FDG). The method is rapid, robust, and site-specific (radiochemical yields > 25%, not decay corrected). The availability of 18F-2-deoxyfluoroglucose avoids the need for more complicated chemistries used to generate carbon–fluorine bonds. We demonstrate the utility of the method by detecting heterotopic pancreatic tumors in mice by PET, using anti-Class II MHC single domain antibodies. We correlate macroscopic PET images with microscopic two-photon visualization of the tumor. Our approach provides easy access to 18F-labeled antibodies and their fragments at a level of molecular specificity that complements conventional 18F-FDG imaging. PMID:26955657

  18. Positron Emission Tomography/Computed Tomography Imaging of Residual Skull Base Chordoma Before Radiotherapy Using Fluoromisonidazole and Fluorodeoxyglucose: Potential Consequences for Dose Painting

    SciTech Connect

    Mammar, Hamid; Kerrou, Khaldoun; Nataf, Valerie; Pontvert, Dominique; Clemenceau, Stephane; Lot, Guillaume; George, Bernard; Polivka, Marc; Mokhtari, Karima; Ferrand, Regis; Feuvret, Loiec; Habrand, Jean-louis; Pouyssegur, Jacques; Mazure, Nathalie; Talbot, Jean-Noeel

    2012-11-01

    Purpose: To detect the presence of hypoxic tissue, which is known to increase the radioresistant phenotype, by its uptake of fluoromisonidazole (18F) (FMISO) using hybrid positron emission tomography/computed tomography (PET/CT) imaging, and to compare it with the glucose-avid tumor tissue imaged with fluorodeoxyglucose (18F) (FDG), in residual postsurgical skull base chordoma scheduled for radiotherapy. Patients and Methods: Seven patients with incompletely resected skull base chordomas were planned for high-dose radiotherapy (dose {>=}70 Gy). All 7 patients underwent FDG and FMISO PET/CT. Images were analyzed qualitatively by visual examination and semiquantitatively by computing the ratio of the maximal standardized uptake value (SUVmax) of the tumor and cerebellum (T/C R), with delineation of lesions on conventional imaging. Results: Of the eight lesion sites imaged with FDG PET/CT, only one was visible, whereas seven of nine lesions were visible on FMISO PET/CT. The median SUVmax in the tumor area was 2.8 g/mL (minimum 2.1; maximum 3.5) for FDG and 0.83 g/mL (minimum 0.3; maximum 1.2) for FMISO. The T/C R values ranged between 0.30 and 0.63 for FDG (median, 0.41) and between 0.75 and 2.20 for FMISO (median,1.59). FMISO T/C R >1 in six lesions suggested the presence of hypoxic tissue. There was no correlation between FMISO and FDG uptake in individual chordomas (r = 0.18, p = 0.7). Conclusion: FMISO PET/CT enables imaging of the hypoxic component in residual chordomas. In the future, it could help to better define boosted volumes for irradiation and to overcome the radioresistance of these lesions. No relationship was founded between hypoxia and glucose metabolism in these tumors after initial surgery.

  19. Contrast-Enhanced [{sup 18}F]fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography for Staging and Radiotherapy Planning in Patients With Anal Cancer

    SciTech Connect

    Bannas, Peter; Weber, Christoph; Adam, Gerhard; Frenzel, Thorsten; Derlin, Thorsten; Mester, Janos; Klutmann, Susanne

    2011-10-01

    Purpose: The practice of surgical staging and treatment of anal cancer has been replaced by noninvasive staging and combined modality therapy. For appropriate patient management, accurate lymph node staging is crucial. The present study evaluated the feasibility and diagnostic accuracy of contrast-enhanced [{sup 18}F]fluoro-2-deoxy-D-glucose ([{sup 18}F]FDG)-positron emission tomography/computed tomography (PET/CT) for staging and radiotherapy planning of anal cancer. Methods and Materials: A total of 22 consecutive patients (median age, 61 years old) with anal cancer underwent complete staging evaluation including physical examination, biopsy of the primary tumor, and contrast-enhanced (ce)-PET/CT. Patients were positioned as they would be for their subsequent radiotherapy. PET and CT images were evaluated independently for detectability and localization of the primary tumor, pelvic and inguinal lymph nodes, and distant metastasis. The stage, determined by CT or PET alone, and the proposed therapy planning were compared with the stage and management determined by ce-PET/CT. Data from ce-PET/CT were used for radiotherapy planning. Results: ce-PET/CT revealed locoregional lymph node metastasis in 11 of 22 patients (50%). After simultaneous reading of PET and CT data sets by experienced observers, 3 patients (14%) were found to have sites of disease not seen on CT that were identified on PET. Two patients had sites of disease not seen on PET that were identified on CT. In summary, 2 patients were upstaged, and 4 patients were downstaged due to ce-PET/CT. However, radiotherapy fields were changed due to the results from ce-PET/CT in 23% of cases compared to CT or PET results alone. Conclusions: ce-PET/CT is superior to PET or CT alone for staging of anal cancer, with significant impact on therapy planning.

  20. [{sup 18}F]FDG-Positron Emission Tomography Coregistration With Computed Tomography Scans for Radiation Treatment Planning of Lymphoma and Hematologic Malignancies

    SciTech Connect

    Terezakis, Stephanie A.; Hunt, Margie A.; Kowalski, Alexander; McCann, Patrick; Schmidtlein, C. Ross; Reiner, Anne; Goenen, Mithat; Kirov, Assen S.; Gonzales, Anne Marie; Schoeder, Heiko; Yahalom, Joachim

    2011-11-01

    Purpose: Positron emission-tomography (PET) using 2-[{sup 18}F]fluoro-2-deoxyglucose (FDG-PET) increases sensitivity and specificity of disease detection in lymphoma and thus is standard in lymphoma management. This study examines the effects of coregistering FDG-PET and computed tomography (CT) (PET/CT) scans on treatment planning for lymphoma patients. Methods and Materials: Twenty-nine patients (30 positive PET scans) underwent PET/CT treatment planning from July 2004 to February 2007 and were retrospectively studied. For each patient, gross tumor volume was blindly contoured on the CT-only and PET/CT studies by a radiation oncologist. Treatment plans were generated for both the CT-only and PET/CT planning target volumes (PTVs) for all patients. Normal tissue doses and PTV coverage were evaluated using dose--volume histograms for all sites. Results: Thirty-two treatment sites were evaluated. Twenty-one patients had non-Hodgkin lymphoma, 5 patients had Hodgkin lymphoma, and 3 patients had plasma cell neoplasms. Previously undetected FDG-avid sites were identified in 3 patients during PET/CT simulation, resulting in one additional treatment field. Due to unexpected PET/CT simulation findings, 2 patients did not proceed with radiation treatment. The addition of PET changed the volume of 23 sites (72%). The PTV was increased in 15 sites (47%) by a median of 11% (range, 6-40%) and reduced in 8 sites (25%) by a median of 20% (range, 6%-75%). In six (19%) replanned sites, the CT-based treatment plan would not have adequately covered the PTV defined by PET/CT. Conclusions: Incorporation of FDG-PET into CT-based treatment planning for lymphoma patients resulted in considerable changes in management, volume definition, and normal tissue dosimetry for a significant number of patients.

  1. ENVIRONMENTAL APPLICATION OF GAS CHROMATOGRAPHY/ATOMIC EMISSION DETECTION

    EPA Science Inventory

    A gas chromatography/atomic emission detector (GC/AED) system has been evaluated for its applicability to environmental analysis. Detection limits, elemental response factors, and regression analysis data were determined for 58 semivolatile environmental contaminants. Detection l...

  2. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-10-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma.

  3. Technetium-99m methylene diphosphonate uptake in the brachialis muscle hematoma in a patient with prostate cancer and coagulation disorder mimicking bone metastasis evaluated by single-photon emission tomography-computed tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshakh; Madhavan, Devdas; Shinto, Ajit Sugunan

    2013-01-01

    We report a case of 79-year-old male with prostate cancer and coagulation disorder presented with left shoulder pain. He underwent bone scintigraphy to rule out metastasis, which showed intense foci of tracer activity in the left axilla. Hybrid single-photon emission tomography-computed tomography (SPECT/CT) of the shoulder region localized tracer uptake to the left brachialis muscle hematoma. PMID:24379534

  4. Effects of Respiration-Averaged Computed Tomography on Positron Emission Tomography/Computed Tomography Quantification and its Potential Impact on Gross Tumor Volume Delineation

    SciTech Connect

    Chi, Pai-Chun Melinda; Mawlawi, Osama; Luo Dershan; Liao Zhongxing; Macapinlac, Homer A.; Pan Tinsu

    2008-07-01

    Purpose: Patient respiratory motion can cause image artifacts in positron emission tomography (PET) from PET/computed tomography (CT) and change the quantification of PET for thoracic patients. In this study, respiration-averaged CT (ACT) was used to remove the artifacts, and the changes in standardized uptake value (SUV) and gross tumor volume (GTV) were quantified. Methods and Materials: We incorporated the ACT acquisition in a PET/CT session for 216 lung patients, generating two PET/CT data sets for each patient. The first data set (PET{sub HCT}/HCT) contained the clinical PET/CT in which PET was attenuation corrected with a helical CT (HCT). The second data set (PET{sub ACT}/ACT) contained the PET/CT in which PET was corrected with ACT. We quantified the differences between the two datasets in image alignment, maximum SUV (SUV{sub max}), and GTV contours. Results: Of the patients, 68% demonstrated respiratory artifacts in the PET{sub HCT}, and for all patients the artifact was removed or reduced in the corresponding PET{sub ACT}. The impact of respiration artifact was the worst for lesions less than 50 cm{sup 3} and located below the dome of the diaphragm. For lesions in this group, the mean SUV{sub max} difference, GTV volume change, shift in GTV centroid location, and concordance index were 21%, 154%, 2.4 mm, and 0.61, respectively. Conclusion: This study benchmarked the differences between the PET data with and without artifacts. It is important to pay attention to the potential existence of these artifacts during GTV contouring, as such artifacts may increase the uncertainties in the lesion volume and the centroid location.

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

    PubMed

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

    1999-10-01

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

  6. 18F-fluorodeoxyglucose and 18F-flumazenil positron emission tomography in patients with refractory epilepsy

    PubMed Central

    Topakian, Raffi; Pichler, Robert

    2016-01-01

    Abstract Background Epilepsy is a neurological disorder characterized by epileptic seizures as a result of excessive neuronal activity in the brain. Approximately 65 million people worldwide suffer from epilepsy; 20–40% of them are refractory to medication therapy. Early detection of disease is crucial in the management of patients with epilepsy. Correct localization of the ictal onset zone is associated with a better surgical outcome. The modern non-invasive techniques used for structural-functional localization of the seizure focus includes electroencephalography (EEG) monitoring, magnetic resonance imaging (MRI), single photon emission tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT). PET/CT can predict surgical outcome in patients with refractory epilepsy. The aim of the article is to review the current role of routinely used tracer 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) as well as non routinely used 18F-Flumazenil (18F-FMZ) tracers PET/CT in patients with refractory epilepsy. Conclusions Functional information delivered by PET and the morphologic information delivered by CT or MRI are essential in presurgical evaluation of epilepsy. Nowadays 18F-FDG PET/CT is a routinely performed imaging modality in localization of the ictal onset zone in patients with refractory epilepsy who are unresponsive to medication therapy. Unfortunately, 18F-FDG is not an ideal PET tracer regarding the management of patients with epilepsy: areas of glucose hypometabolism do not correlate precisely with the proven degree of change within hippocampal sclerosis, as observed by histopathology or MRI. Benzodiazepine-receptor imaging is a promising alternative in nuclear medicine imaging of epileptogenic focus. The use of 11C-FMZ in clinical practice has been limited by its short half-life and necessitating an on-site cyclotron for production. Therefore, 18F-FMZ might be established as one of the tracers of choice for patients

  7. 18F-fluorodeoxyglucose and 18F-flumazenil positron emission tomography in patients with refractory epilepsy

    PubMed Central

    Topakian, Raffi; Pichler, Robert

    2016-01-01

    Abstract Background Epilepsy is a neurological disorder characterized by epileptic seizures as a result of excessive neuronal activity in the brain. Approximately 65 million people worldwide suffer from epilepsy; 20–40% of them are refractory to medication therapy. Early detection of disease is crucial in the management of patients with epilepsy. Correct localization of the ictal onset zone is associated with a better surgical outcome. The modern non-invasive techniques used for structural-functional localization of the seizure focus includes electroencephalography (EEG) monitoring, magnetic resonance imaging (MRI), single photon emission tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT). PET/CT can predict surgical outcome in patients with refractory epilepsy. The aim of the article is to review the current role of routinely used tracer 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) as well as non routinely used 18F-Flumazenil (18F-FMZ) tracers PET/CT in patients with refractory epilepsy. Conclusions Functional information delivered by PET and the morphologic information delivered by CT or MRI are essential in presurgical evaluation of epilepsy. Nowadays 18F-FDG PET/CT is a routinely performed imaging modality in localization of the ictal onset zone in patients with refractory epilepsy who are unresponsive to medication therapy. Unfortunately, 18F-FDG is not an ideal PET tracer regarding the management of patients with epilepsy: areas of glucose hypometabolism do not correlate precisely with the proven degree of change within hippocampal sclerosis, as observed by histopathology or MRI. Benzodiazepine-receptor imaging is a promising alternative in nuclear medicine imaging of epileptogenic focus. The use of 11C-FMZ in clinical practice has been limited by its short half-life and necessitating an on-site cyclotron for production. Therefore, 18F-FMZ might be established as one of the tracers of choice for patients

  8. Distributed microprocessor automation network for synthesizing radiotracers used in positron emission tomography

    SciTech Connect

    Russell, J.A.G.; Alexoff, D.L.; Wolf, A.P.

    1984-09-01

    This presentation describes an evolving distributed microprocessor network for automating the routine production synthesis of radiotracers used in Positron Emission Tomography. We first present a brief overview of the PET method for measuring biological function, and then outline the general procedure for producing a radiotracer. The paper identifies several reasons for our automating the syntheses of these compounds. There is a description of the distributed microprocessor network architecture chosen and the rationale for that choice. Finally, we speculate about how this network may be exploited to extend the power of the PET method from the large university or National Laboratory to the biomedical research and clinical community at large. 20 refs. (DT)

  9. New Cyclotron Targetry to Enhance F-18 clinical Position Emission Tomography

    SciTech Connect

    J. Michael Doster

    2008-12-19

    This project proposes to develop cyclotron targets that produce F-18 for clinical Positron Emission Tomography (PET) at significantly higher rates than that available from current targetry. This production rate of 18F is directly proportional to the beam current. Higher beam currents would result in increased 18F production but would be accompanied by higher heat loads to the target. The beam power available in most commercial cyclotrons exceeds the heat removal capacity of current target technology by a factor of two to four, significantly limiting the production rate of Fluorine-18.

  10. Clinical correlates of decreased anteroposterior metabolic gradients in positron emission tomography (PET) of schizophrenic patients

    SciTech Connect

    DeLisi, L.E.; Buchsbaum, M.S.; Holcomb, H.H.; Dowling-Zimmerman, S.; Pickar, D.; Boronow, J.; Morihisa, J.M.; van Kammen, D.P.; Carpenter, W.; Kessler, R.

    1985-01-01

    The finding in schizophrenic patients of a reversal of the normal frontal to posterior pattern of brain metabolic activity with positron emission tomography (PET) is of interest, but its relevance to psychopathology is unknown. Using PET, the authors studied 21 patients with chronic schizophrenia and 21 age- and sex-matched control subjects. Although eight of the 21 patients and only one of the control subjects showed a relatively lower anteroposterior metabolic gradient, no clinical correlates of this finding were noted. In addition, cerebral atrophy, as determined by CAT scan, was not associated with this aberrant metabolic pattern.

  11. Radiolabeled Phosphonium Salts as Mitochondrial Voltage Sensors for Positron Emission Tomography Myocardial Imaging Agents.

    PubMed

    Kim, Dong-Yeon; Min, Jung-Joon

    2016-09-01

    Despite substantial advances in the diagnosis of cardiovascular disease, (18)F-labeled positron emission tomography (PET) radiopharmaceuticals remain necessary to diagnose heart disease because clinical use of current PET tracers is limited by their short half-life. Lipophilic cations such as phosphonium salts penetrate the mitochondrial membranes and accumulate in mitochondria of cardiomyocytes in response to negative inner-transmembrane potentials. Radiolabeled tetraphenylphosphonium cation derivatives have been developed as myocardial imaging agents for PET. In this review, a general overview of these radiotracers, including their radiosynthesis, in vivo characterization, and evaluation is provided and clinical perspectives are discussed. PMID:27540422

  12. Distributed Microprocessor Automation Network for Synthesizing Radiotracers Used in Positron Emission Tomography [PET

    DOE R&D Accomplishments Database

    Russell, J. A. G.; Alexoff, D. L.; Wolf, A. P.

    1984-09-01

    This presentation describes an evolving distributed microprocessor network for automating the routine production synthesis of radiotracers used in Positron Emission Tomography. We first present a brief overview of the PET method for measuring biological function, and then outline the general procedure for producing a radiotracer. The paper identifies several reasons for our automating the syntheses of these compounds. There is a description of the distributed microprocessor network architecture chosen and the rationale for that choice. Finally, we speculate about how this network may be exploited to extend the power of the PET method from the large university or National Laboratory to the biomedical research and clinical community at large. (DT)

  13. Using Positron Emission Tomography to Study Transporter-Mediated Drug–Drug Interactions in Tissues

    PubMed Central

    Wulkersdorfer, B; Wanek, T; Bauer, M; Zeitlinger, M; Müller, M; Langer, O

    2014-01-01

    Drug disposition is highly regulated by membrane transporters. Some transporter-mediated drug–drug interactions (DDIs) may not manifest themselves in changes in systemic exposure but rather in changes in tissue exposure of drugs. To better assess the impact of transporter-mediated DDIs in tissues, positron emission tomography (PET)—a noninvasive imaging method—plays an increasingly important role. In this article, we provide examples of how PET can be used to assess transporter-mediated DDIs in different organs. PMID:24682030

  14. [18F]-fluoride positron emission tomography for imaging condylar hyperplasia.

    PubMed

    Laverick, S; Bounds, G; Wong, Wai Lup

    2009-04-01

    The management of condylar hyperplasia depends on the diagnosis of continued growth in the affected condyle, and there is currently no satisfactory way of imaging it. [(18)F]-fluoride positron emission tomography (PET) was included in the investigation of 5 patients who were suspected of having condylar hyperplasia, and the results were correlated with the operative findings. The technique correctly identified condylar hyperplasia in all patients. Our results suggest that [(18)F]-fluoride PET is a valid way of assessing patients with condylar hyperplasia. PMID:18926607

  15. Positron Emission Tomography-Scanner at Children`s Hospital of Michigan at Detroit, Michigan

    SciTech Connect

    Not Available

    1992-12-31

    The Department of Energy has prepared an environmental assessment (EA), DOE/EA-0795, to support the DOE decision to provide a grant of $7,953,600 to be used in support of a proposed Positron Emission Tomography Scanner at Children`s Hospital of Michigan at Detroit, Michigan. Based upon the analysis in the EA, DOE has determined that the proposed action is not a major Federal action significantly affected the quality of the human environment within the meaning of the National Environmental Policy Act of 1969 (NEPA). Therefore, the preparation of an Environmental Impact Statement is not required and DOE is issuing this Finding of No Significant Impact (FONSI).

  16. Florbetapir (18F) for brain amyloid positron emission tomography: highlights on the European marketing approval.

    PubMed

    Cortes-Blanco, Anabel; Prieto-Yerro, Concha; Martinez-Lazaro, Raul; Zamora, Javier; Jiménez-Huete, Adolfo; Haberkamp, Marion; Pohly, Johannes; Enzmann, Harald; Zinserling, Jörg; Strassmann, Valerie; Broich, Karl

    2014-10-01

    Florbetapir (18F) for brain amyloid positron emission tomography (PET) imaging has been recently approved in Europe to estimate β-amyloid neuritic plaque density in the brain when the subject is still alive. Such density is one of the key issues for the definitive diagnosis of Alzheimer's disease (AD) at autopsy. This capability of florbetapir (18F) is regarded as a significant improvement in the diagnostic procedures for adult patients with cognitive impairment who are being evaluated for AD and other causes of cognitive impairment. The current paper highlights the specific characteristics of the European marketing authorization of florbetapir (18F).

  17. Hemispheric encoding/retrieval asymmetry in episodic memory: positron emission tomography findings.

    PubMed Central

    Tulving, E; Kapur, S; Craik, F I; Moscovitch, M; Houle, S

    1994-01-01

    Data are reviewed from positron emission tomography studies of encoding and retrieval processes in episodic memory. These data suggest a hemispheric encoding/retrieval asymmetry model of prefrontal involvement in encoding and retrieval of episodic memory. According to this model, the left and right prefrontal lobes are part of an extensive neuronal network that subserves episodic remembering, but the two prefrontal hemispheres play different roles. Left prefrontal cortical regions are differentially more involved in retrieval of information from semantic memory and in simultaneously encoding novel aspects of the retrieved information into episodic memory. Right prefrontal cortical regions, on the other hand, are differentially more involved in episodic memory retrieval. PMID:8134342

  18. In vivo measurement of regional cerebral haematocrit using positron emission tomography

    SciTech Connect

    Lammertsma, A.A.; Brooks, D.J.; Beaney, R.P.; Turton, D.R.; Kensett, M.J.; Heather, J.D.; Marshall, J.; Jones, T.

    1984-09-01

    A method is described for measuring the regional cerebral-to-large vessel haematocrit ratio using inhalation of carbon-11-labelled carbon monoxide and the intravenous injection of carbon-11-labelled methyl-albumin in combination with positron emission tomography. The mean value in a series of nine subjects was 0.69. This is approximately 20% lower than the value of 0.85 previously reported. It is concluded that previous measurements of regional cerebral blood volume using a haematocrit ratio of 0.85 will have underestimated the value of regional cerebral blood volume by 20%.

  19. An advanced fully 3D OSEM reconstruction for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Yun, Ming-Kai; Liu, Shuang-Quan; Shan, Bao-Gi; Wei, Long

    2010-02-01

    A fully 3D OSEM reconstruction method for positron emission tomography (PET) based on symmetries and sparse matrix technique is described. Great savings in both storage space and computation time were achieved by exploiting the symmetries of scanner and sparseness of the system matrix. More reduction of storage requirement was obtained by introducing the approximation of system matrix. Iteration-filter was performed to restrict image noise in reconstruction. Performances of simulation data and phantom data got from Micro-PET (Type: Epuls-166) demonstrated that similar image quality was achieved using the approximation of the system matrix.

  20. Clinical and research applications of simultaneous positron emission tomography and MRI

    PubMed Central

    Fraioli, F

    2014-01-01

    Abstract Evaluation of the molecular processes responsible for disease pathogenesis and progression represents the new frontier of clinical radiology. Multimodality imaging lies at the cutting edge, combining the power of MRI for tissue characterization, microstructural appraisal and functional assessment together with new positron emission tomography (PET) tracers designed to target specific metabolic processes. The recent commercial availability of an integrated clinical whole-body PET-MRI provides a hybrid platform for exploring and exploiting the synergies of multimodal imaging. First experiences on the clinical and research application of hybrid PET-MRI are emerging. This article reviews the rapidly evolving field and speculates on the potential future direction. PMID:24234585

  1. Brain positron emission tomography in splenectomized adults with β-thalassemia intermedia: uncovering yet another covert abnormality.

    PubMed

    Musallam, Khaled M; Nasreddine, Wassim; Beydoun, Ahmad; Hourani, Roula; Hankir, Ahmed; Koussa, Suzanne; Haidar, Mohamad; Taher, Ali T

    2012-02-01

    Covert brain infarction is an emerging concern in patients with β-thalassemia intermedia (TI). We have recently observed a high prevalence (60%) of silent brain infarction on brain magnetic resonance imaging (MRI) in 30 splenectomized adults with TI. In this work, we further evaluate cerebral involvement in the same 30 patients using fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scanning. The median age was 32 years (range, 18-54 years) with a male to female ratio of 13:17. Nineteen patients (63.3%) had evidence of decreased neuronal function on PET-CT. Involvement was mostly left sided, multiple, and most commonly in the temporal and parietal lobes. Elevated liver iron concentration, beyond 15 mg Fe/g dry weight, characterized patients with decreased neuronal function. The concordance rate between brain MRI and PET-CT for the detection of brain abnormality was only 36.7% (Kappa 0.056, P = 0.757), highlighting that both modalities reveal different types of brain pathology. Decreased neuronal function is a common finding in patients with TI and is associated with iron overload. Moreover, the addition of PET-CT to MRI identifies a greater proportion of TI patients with silent neuroimaging abnormalities.

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

    PubMed Central

    2010-01-01

    Magnetic Resonance Imaging for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Pease note that two related evidence-based analyses of non-invasive cardiac imaging technologies for the assessment of myocardial viability are also available on the MAS website: Positron Emission Tomography for the Assessment of Myocardial Viability: An Evidence-Based Analysis Magnetic Resonance Imaging for the Assessment of Myocardial Viability: an Evidence-Based Analysis The Toronto Health Economics and Technology Assessment Collaborative has also produced an associated economic report entitled: The Relative Cost-effectiveness of Five Non-invasive Cardiac Imaging Technologies for Diagnosing Coronary Artery Disease in Ontario [Internet]. Available from: http://theta.utoronto.ca/reports/?id=7 Objective The objective of the analysis is to determine the diagnostic accuracy of single photon emission tomography (SPECT) in the diagnosis of coronary artery disease (CAD) compared to the reference standard of coronary angiography (CA). The analysis is primarily meant to allow for indirect comparisons between non-invasive strategies for the diagnosis of CAD, using CA as a reference standard. SPECT Cardiac SPECT, or myocardial perfusion scintigraphy (MPS), is a widely used nuclear, non-invasive image acquisition technique for investigating ischemic heart disease. SPECT is currently appropriate for all aspects of detecting and managing ischemic heart disease including diagnosis, risk assessment/stratification, assessment of myocardial viability, and the evaluation of left ventricular function. Myocardial perfusion scintigraphy was originally developed as a two-dimensional planar imaging technique, but SPECT acquisition has since become the clinical standard in current practice. Cardiac SPECT for the diagnosis of CAD uses an intravenously administered radiopharmaceutical tracer to evaluate regional coronary blood flow usually at rest and after stress. The radioactive tracers thallium

  3. Positron emission tomography of lung tumors and mediastinal lymph nodes using [18F]fluorodeoxyglucose. The Members of the PET-Lung Tumor Study Group.

    PubMed

    Scott, W J; Schwabe, J L; Gupta, N C; Dewan, N A; Reeb, S D; Sugimoto, J T

    1994-09-01

    Positron emission tomography detects increased glucose uptake in malignant tissue using the glucose analogue [2-18F]fluoro-2-deoxy-D-glucose. We reviewed the scans obtained in 62 patients with lung tumors. All had undergone computed tomography and had tissue-based diagnoses: 22 had adenocarcinomas, 12 had squamous cell carcinomas, 13 had other malignancies, 1 had organizing pneumonia, 1 had a hamartoma, and 13 had granulomas. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified 44 of 47 malignancies. Two of three false-negative findings were tumors that were 1 cm2 or less and the other was a bronchioloalveolar carcinoma. All three false-positive findings were granulomas. The sensitivity and specificity of the technique were 93.6% and 80%, respectively, and the positive and negative predictive values were 93.6% and 80%, respectively. The differential uptake ratio was determined in all 62 patients. The mean differential uptake ratio (+/- the standard error of the mean) for malignant tumors was 6.4 +/- 0.56 and that for benign tumors was 1.14 +/- 0.26 (p < 0.0001, t test). Twenty-five of the patients had N2 lymph nodes evaluated pathologically. Positron emission tomography with [2-18F]fluoro-2-deoxy-D-glucose identified negative N2 nodes in 19 of 22 patients (86%) with negative nodes and positive N2 nodes in 2 of 3 patients (66%) with positive nodes, including one instance missed by computed tomography.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7944691

  4. [18F]-Fluoromisonidazole Positron Emission Tomography/Computed Tomography Visualization of Tumor Hypoxia in Patients With Chordoma of the Mobile and Sacrococcygeal Spine

    SciTech Connect

    Cheney, Matthew D.; Chen, Yen-Lin; Lim, Ruth; Winrich, Barbara K.; Grosu, Anca L.; Trofimov, Alexei V.; Depauw, Nicolas; Shih, Helen A.; Schwab, Joseph H.; Hornicek, Francis J.; DeLaney, Thomas F.

    2014-12-01

    Purpose: To investigate [18F]-fluoromisonidazole positron emission tomography/computed tomography (FMISO-PET/CT) detection of targetable hypoxic subvolumes (HSVs) in chordoma of the mobile or sacrococcygeal spine. Methods and Materials: A prospective, pilot study of 20 patients with primary or locally recurrent chordoma of the mobile or sacrococcygeal spine treated with proton or combined proton/photon radiation therapy (RT) with or without surgery was completed. The FMISO-PET/CT was performed before RT and after 19.8-34.2 GyRBE (relative biologic effectiveness). Gross tumor volumes were delineated and HSVs defined including voxels with standardized uptake values ≥1.4 times the muscle mean. Clinical characteristics and treatments received were compared between patients with and without HSVs. Results: The FMISO-PET/CT detected HSVs in 12 of 20 patients (60%). Baseline and interval HSV spatial concordance varied (0%-94%). Eight HSVs were sufficiently large (≥5 cm{sup 3}) to potentially allow an intensity modulated proton therapy boost. Patients with HSVs had significantly larger gross tumor volumes (median 410.0 cm{sup 3} vs 63.4 cm{sup 3}; P=.02) and were significantly more likely to have stage T2 tumors (5 of 12 vs 0 of 8; P=.04). After a median follow-up of 1.8 years (range, 0.2-4.4 years), a local recurrence has yet to be observed. Three patients developed metastatic disease, 2 with HSVs. Conclusions: Detection of targetable HSVs by FMISO-PET/CT within patients undergoing RT with or without surgery for treatment of chordoma of the mobile and sacrococcygeal spine is feasible. The study's inability to attribute interval HSV changes to treatment, rapidly changing hypoxic physiology, or imaging inconsistencies is a limitation. Further study of double-baseline FMISO-PET/CT and hypoxia-directed RT dose escalation, particularly in patients at high risk for local recurrence, is warranted.

  5. A comparison study of 11C-methionine and 18F-fluorodeoxyglucose positron emission tomography-computed tomography scans in evaluation of patients with recurrent brain tumors

    PubMed Central

    Sharma, Rajnish; D’Souza, Maria; Jaimini, Abhinav; Hazari, Puja Panwar; Saw, Sanjeev; Pandey, Santosh; Singh, Dinesh; Solanki, Yachna; Kumar, Nitin; Mishra, Anil K.; Mondal, Anupam

    2016-01-01

    Introduction: 11C-methonine ([11C]-MET) positron emission tomography-computed tomography (PET-CT) is a well-established technique for evaluation of tumor for diagnosis and treatment planning in neurooncology. [11C]-MET reflects amino acid transport and has been shown to be more sensitive than magnetic resonance imaging (MRI) in stereotactic biopsy planning. This study compared fluorodeoxyglucose (FDG) PET-CT and MET PET-CT in the detection of various brain tumors. Materials and Methods: Sixty-four subjects of brain tumor treated by surgery, chemotherapy, and/or radiotherapy were subjected to [18F]-FDG, [11C]-MET, and MRI scan. The lesion was analyzed semiquantitatively using tumor to normal contralateral ratio. The diagnosis was confirmed by surgery, stereotactic biopsy, clinical follow-up, MRI, or CT scans. Results: Tumor recurrence was found in 5 out of 22 patients on [F-18] FDG scan while [11C]-MET was able to detect recurrence in 18 out of 22 patients in low-grade gliomas. Two of these patients were false positive for the presence of recurrence of tumor and later found to be harboring necrosis. Among oligodendroglioma, medulloblastoma and high-grade glioma out of 42 patients 39 were found to be concordant MET and FDG scans. On semiquantitative analysis, mean T/NT ratio was found to be 2.96 ± 0.94 for lesions positive for recurrence of tumors and 1.18 ± 0.74 for lesions negative for recurrence of tumor on [11C]-MET scan. While the ratio for FDG scan on semiquantitative analysis was found to be 2.05 ± 1.04 for lesions positive for recurrence of tumors and 0.52 ± 0.15 for lesions negative for recurrence of tumors. Conclusion: The study highlight that [11C]-MET is superior to [18F]-FDG PET scans to detect recurrence in low-grade glioma. A cut-off value of target to nontarget value of 1.47 is a useful parameter to distinguish benign from malignant lesion on an [11C]-MET Scan. Both [18F]-FDG and [11C]-MET scans were found to be useful in high-grade astrocytoma

  6. Active subcutaneous calcinosis demonstrated by fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in a case of limited cutaneous systemic sclerosis.

    PubMed

    Vadrucci, Manuela; Castellani, Massimo; Benti, Riccardo

    2016-01-01

    Systemic sclerosis (SSc) is a rheumatic autoimmune disease of unknown origin causing fibrosis of the skin and the internal organs. The limited cutaneous variant is the most common subtype of SSc, and it is predominantly characterized by skin and soft-tissues involvement. A 72-year-old woman, who had been diagnosed with the limited cutaneous form of SSc 16 years before, underwent fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) examination due to unexplained weight loss and recent onset of fatigue and joint pain. PET/CT images showed widespread soft-tissue calcinosis characterized by elevated glucose uptake. PMID:27095870

  7. The distinctive role of positron emission tomography/computed tomography in breast carcinoma with brown adipose tissue 2-fluoro-2-deoxy-d-glucose uptake.

    PubMed

    Heiba, Sherif I; Bernik, Stephanie; Raphael, Barbara; Sandella, Nick; Cholewinski, Witold; Klein, Paula

    2005-01-01

    The diagnostic power of an integrated positron emission tomography/computed tomography (PET/CT) system for whole-body 2-fluoro-2-deoxy-d-glucose (FDG) imaging is clearly demonstrated in this case report. The precise anatomic localization of FDG uptake with CT in a PET/CT scan of a patient with known breast carcinoma helped identify a contralateral breast tumor with axillary lymph node metastasis despite the presence of extensive physiologic brown fat FDG uptake. Accordingly, the patient received appropriate surgical management and pathologic confirmation of the disease.

  8. Image findings of monomorphic non-hogdkin lymphoproliferative disorder in a post renal transplant patient diagnosed with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusamy; Rajasekar, Thirugnanam; Shibu, Deepu; Radhakrishnan, Edathurthy Kalarikal; Shinto, Ajit Sugunan

    2014-07-01

    Post-transplant lymphoproliferative disorder (PTLD) is a heterogeneous group of lymphoid proliferations caused by immunosuppression after solid organ or bone marrow transplantation. PTLD is categorized by early lesion, polymorphic PTLD and monomorphic PTLD. Fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) scans have clinical significance in the evaluation of PTLD following renal transplantation. We report imaging findings of a monomorphic non-Hodgkin lymphoma, post renal transplant seen on FDG PET/CT in a 32-year-old lactating woman. Whole body FDG- ET/CT demonstrated uptake in right external iliac and inguinal lymph nodes.

  9. Image findings of monomorphic non-hogdkin lymphoproliferative disorder in a post renal transplant patient diagnosed with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusamy; Rajasekar, Thirugnanam; Shibu, Deepu; Radhakrishnan, Edathurthy Kalarikal; Shinto, Ajit Sugunan

    2014-01-01

    Post-transplant lymphoproliferative disorder (PTLD) is a heterogeneous group of lymphoid proliferations caused by immunosuppression after solid organ or bone marrow transplantation. PTLD is categorized by early lesion, polymorphic PTLD and monomorphic PTLD. Fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) scans have clinical significance in the evaluation of PTLD following renal transplantation. We report imaging findings of a monomorphic non-Hodgkin lymphoma, post renal transplant seen on FDG PET/CT in a 32-year-old lactating woman. Whole body FDG- ET/CT demonstrated uptake in right external iliac and inguinal lymph nodes. PMID:25210292

  10. Calcified peritoneal metastasis identified on 18F-fluoride positron emission tomography/computed tomography: Importance of extraosseous uptake of F-18 fluoride

    PubMed Central

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

    2016-01-01

    F-18 NaF positron emission tomography/computed tomography (PET/CT) is used for the evaluation of malignant and nonmalignant osseous disease. Extraosseous uptake of 18 fluoride-NaF has been observed in the arterial vasculature, gastrointestinal tract, and genitourinary tract. We describe a case of a woman with carcinoma of unknown primary in whom F-18 NaF PET/CT showed tracer uptake in the calcified peritoneal metastasis. Extraosseous findings on F-18 NaF PET/CT, though rare, may be visualized and may result in important management changes. PMID:27095869

  11. Late metastatic recurrence of penile carcinoma after 10 years: Demonstration with 18F-fluorodeoxyglucose positron emission tomography/computed tomography

    PubMed Central

    Sharma, Punit

    2016-01-01

    Penile cancer is rare cancer. While inguinal and pelvic nodal metastasis is common, distant metastasis is rare. We here present the interesting case of a 59-year-old male patient with penile carcinoma, previously treated with penectomy and inguinal lymphadenectomy 10 years earlier. He presented with bone pains and given history of malignancy he was referred for an 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT). PET/CT demonstrated multiple 18F-FDG avid bone and lung metastases. No locoregional disease was seen. Biopsy from a lung nodule confirmed the diagnosis, and the patient was started on palliative chemotherapy. PMID:27385892

  12. Hypertrophic pulmonary osteoarthropathy on bone scintigraphy and 18F-fluorodeoxyglucose positron emission tomography/computed tomography in a patient with lung adenocarcinoma

    PubMed Central

    Cengiz, Arzu; Eren, Mine Şencan; Polatli, Mehmet; Yürekli, Yakup

    2015-01-01

    Hypertrophic pulmonary osteoarthropathy (HPOA) is not an uncommon paraneoplastic syndrome that is frequently associated with lung cancer. A 54-year-old male patient with lung adenocarcinoma underwent bone scintigraphy and fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scanning for initial staging. Bone scintigraphy revealed increased periosteal activity in lower extremities. FDG PET/CT revealed hypermetabolic right lung mass, mediastinal lymph nodes, and mildly increased periosteal FDG uptake in both femurs and tibias. The findings in lower extremities on bone scan and FDG PET/CT were interpreted as HPOA. PMID:26170569

  13. A rare case of extensive skeletal muscle metastases in adenocarcinoma cervix identified by 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan

    PubMed Central

    Vishnoi, Madan Gopal; Jain, Anurag; John, Arun Ravi; Paliwal, Dharmesh

    2016-01-01

    Adenocarcinoma cervix is an uncommon histological subtype of carcinoma cervix; further incidence of skeletal muscle metastases is even rarer. We report the identification of extensive fluorodeoxyglucose (FDG) avid metastatic skeletal muscle deposits in a known case of adenocarcinoma cervix. The largest lesion representative of muscle deposit in the right deltoid was histopathologically confirmed to be metastatic poorly differentiated carcinoma. This report also serves to highlight the importance of 18F-FDG positron emission tomography/computed tomography (CT) as compared to conventional imaging modalities such as CT and ultrasonography and comments better over the description of invasiveness as well as the extent of disease in carcinoma cervix. PMID:27385895

  14. The distinctive role of positron emission tomography/computed tomography in breast carcinoma with brown adipose tissue 2-fluoro-2-deoxy-d-glucose uptake.

    PubMed

    Heiba, Sherif I; Bernik, Stephanie; Raphael, Barbara; Sandella, Nick; Cholewinski, Witold; Klein, Paula

    2005-01-01

    The diagnostic power of an integrated positron emission tomography/computed tomography (PET/CT) system for whole-body 2-fluoro-2-deoxy-d-glucose (FDG) imaging is clearly demonstrated in this case report. The precise anatomic localization of FDG uptake with CT in a PET/CT scan of a patient with known breast carcinoma helped identify a contralateral breast tumor with axillary lymph node metastasis despite the presence of extensive physiologic brown fat FDG uptake. Accordingly, the patient received appropriate surgical management and pathologic confirmation of the disease. PMID:16297092

  15. 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

  16. Carbon nanotube based microfocus field emission x-ray source for microcomputed tomography

    SciTech Connect

    Liu Zejian; Yang Guang; Lee, Yueh Z.; Bordelon, David; Lu Jianping; Zhou, Otto

    2006-09-04

    Microcomputed tomography is now widely used for in vivo small animal imaging for cancer studies. Achieving high imaging quality of live objects requires the x-ray source to have both high spatial and temporal resolutions. Preliminary studies have shown that carbon nanotube (CNT) based field emission x-ray source has significant intrinsic advantages over the conventional thermionic x-ray tube including better temporal resolution and programmability. Here we report the design and characterization of a CNT based field emission x-ray source that also affords a high spatial resolution. The device uses modified asymmetric Einzel lenses for electron focusing and an elliptical shaped CNT cathode patterned by photolithography. Stable and small isotropic x-ray focal spot sizes were obtained.

  17. Cerebral blood volume measured with inhaled C/sup 15/O and positron emission tomography

    SciTech Connect

    Martin, W.R.; Powers, W.J.; Raichle, M.E.

    1987-08-01

    Local cerebral blood volume (CBV) has been measured previously with inhaled /sup 11/CO and positron emission tomography (PET). The model used assumes that equilibrium in tracer concentration has occurred between arterial and systemic venous blood before the PET measurement is made. To verify that this model may be used with the much shorter half-lived C/sup 15/O, we have simultaneously measured arterial and venous blood radioactivity following C/sup 15/O inhalation. Equilibrium occurred 95 +/- 39 s after inhalation (n = 7). If the PET measurement is commenced prior to arteriovenous equilibrium, significant errors occur in calculated CBV. These data indicate that C/sup 15/O may be used as a tracer for CBV measurement provided that emission data collection commences at approximately 120 s after inhalation. Strict quality control measures must be maintained to minimize the contamination of administered C/sup 15/O with /sup 15/O-labeled CO/sub 2/.

  18. 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.

  19. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    PubMed Central

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-01-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy. PMID:24761060

  20. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    PubMed

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-04-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy.

  1. Nonlinearity in single photon detection: modeling and quantum tomography.

    PubMed

    Akhlaghi, Mohsen K; Majedi, A Hamed; Lundeen, Jeff S

    2011-10-24

    Single Photon Detectors are integral to quantum optics and quantum information. Superconducting Nanowire based detectors exhibit new levels of performance, but have no accepted quantum optical model that is valid for multiple input photons. By performing Detector Tomography, we improve the recently proposed model [M.K. Akhlaghi and A.H. Majedi, IEEE Trans. Appl. Supercond. 19, 361 (2009)] and also investigate the manner in which these detectors respond nonlinearly to light, a valuable feature for some applications. We develop a device independent model for Single Photon Detectors that incorporates this nonlinearity. PMID:22108981

  2. Detecting apoptosis using dynamic light scattering with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Farhat, Golnaz; Mariampillai, Adrian; Yang, Victor X. D.; Czarnota, Gregory J.; Kolios, Michael C.

    2011-07-01

    A dynamic light scattering technique is implemented using optical coherence tomography (OCT) to measure the change in intracellular motion as cells undergo apoptosis. Acute myeloid leukemia cells were treated with cisplatin and imaged at a frame rate of 166 Hz using a 1300 nm swept-source OCT system at various times over a period of 48 h. Time correlation analysis of the speckle intensities indicated a significant increase in intracellular motion 24 h after treatment. This rise in intracellular motion correlated with histological findings of irregularly shaped and fragmented cells indicative of cell membrane blebbing and fragmentation.

  3. Three dimensional quantification of left ventricular wall motion by ECG-gated blood pool emission tomography

    SciTech Connect

    Underwood, S.R.; Walton, S.; Laming, P.J.; Jarritt, P.H.; Ell, P.J.; Emanuel, R.W.; Swanton, R.H.

    1985-05-01

    ECG-gated blood pool emission tomography is a relatively new technique, and this study establishes a simple method for displaying the three dimensional data obtained, determines a normal range for ejection fraction in all regions of the left ventricle, and compares wall motion in abnormal subjects with that determined by X-ray contrast ventriculography. The short axis sections dividing the ventricle in slices from apex to base, were used to calculate ejection fraction for all parts of the ventricle and the results were plotted on a single colour coded circular image. The apex was represented in the centre, the base around the circumference, and all other parts of the ventricle were represented in between. The image was divided into 15 segments, and normal segmental ejection fraction was defined as within two standard deviations of the mean in a group of 10 normal subjects. In 25 subjects with coronary artery disease, motion of the anterior, apical, and inferior walls agreed in every case with the right anterior oblique contrast ventriculogram, but in 12 of these, the three dimensional ejection fraction image showed abnormal septal motion, and in a further 3, abnormal lateral wall motion in addition. In the 12 subjects there was disease of the left anterior descending coronary artery, and in the further 3 there was left circumflex disease. ECG-gated blood pool emission tomography thus provides an accurate quantitative assessment of left ventricular wall motion in three dimensions, and has significant advantages over conventional planar techniques.

  4. Catecholamine stimulation, substrate competition, and myocardial glucose uptake in conscious dogs assessed with positron emission tomography.

    PubMed

    Merhige, M E; Ekas, R; Mossberg, K; Taegtmeyer, H; Gould, K L

    1987-11-01

    Uptake of radiolabelled deoxyglucose out of proportion to reduced coronary flow demonstrated by positron emission tomography has been used to identify reversibly ischemic, viable myocardium. For this concept to be applied reliably in the clinical setting, factors that may depress glucose availability independent of tissue viability, such as adrenergic stimulation and substrate competition, must be examined. Accordingly, we studied the effect of catecholamine stimulation by dopamine on myocardial glucose uptake in vivo using chronically instrumented, intact dogs and positron emission tomography. We measured myocardial activity of [2-18F]-2-deoxyglucose (FDG) and 82Rb in glucose-loaded animals randomly studied during dopamine infusion, during insulin infusion, and then during their combined infusion. Myocardial FDG uptake was significantly decreased when animals were treated with dopamine, compared with treatment in the same animals with insulin. When insulin was added to the dopamine infusion, myocardial FDG uptake was restored. In contrast, myocardial activity of 82Rb, which is taken up in proportion to coronary flow, was similar under all three experimental conditions. Plasma glucose, free fatty acid, and lactate concentrations were determined before and during each infusion. The depression of myocardial FDG activity seen during dopamine infusion and its reversal with addition of insulin can be explained on the basis of effects of these hormones on substrate availability and competition.

  5. Element Mapping in Organic Samples Utilizing a Benchtop X-Ray Fluorescence Emission Tomography (XFET) System

    PubMed Central

    Groll, A.; George, J.; Vargas, P.; La Rivière, P.J.; Meng, L. J.

    2015-01-01

    X-ray fluorescence computed tomography (XFCT) is an emerging imaging modality that maps the three-dimensional distribution of elements, generally metals, in ex vivo specimens and potentially in living animals and humans. Building on our previous synchrotron-based work, we experimentally explored the use of a benchtop X-ray fluorescence computed tomography system for mapping trace-metal ions in biological samples. This system utilizes a scanning pencil-beam to stimulate the object and then relies on a detection system, with single or multiple slit apertures placed in front of position-sensitive X-ray detectors, to collect the fluorescence X-rays and to form 3-D elemental map without the need for tomographic imaging reconstruction. The technique was used to generate images of the elemental distributions of a triple-tube phantom and an osmium-stained zebrafish. PMID:26705368

  6. Sodium-22-radiolabeled silica nanoparticles as new radiotracer for biomedical applications: in vivo positron emission tomography imaging, biodistribution, and biocompatibility

    PubMed Central

    Al Faraj, Achraf; Alotaibi, Basem; Shaik, Abjal Pasha; Shamma, Khaled Z; Al Jammaz, Ibrahim; Gerl, Jürgen

    2015-01-01

    Despite their advantageous chemical properties for nuclear imaging, radioactive sodium-22 (22Na) tracers have been excluded for biomedical applications because of their extremely long lifetime. In the current study, we proposed, for the first time, the use of 22Na radiotracers for pre-clinical applications by efficiently loading with silica nanoparticles (SiNPs) and thus offering a new life for this radiotracer. Crown-ether-conjugated SiNPs (300 nm; −0.18±0.1 mV) were successfully loaded with 22Na with a loading efficacy of 98.1%±1.4%. Noninvasive positron emission tomography imaging revealed a transient accumulation of 22Na-loaded SiNPs in the liver and to a lower extent in the spleen, kidneys, and lung. However, the signal gradually decreased in a time-dependent manner to become not detectable starting from 2 weeks postinjection. These observations were confirmed ex vivo by quantifying 22Na radioactivity using γ-counter and silicon content using inductively coupled plasma-mass spectrometry in the blood and the different organs of interest. Quantification of Si content in the urine and feces revealed that SiNPs accumulated in the organs were cleared from the body within a period of 2 weeks and completely in 1 month. Biocompatibility evaluations performed during the 1-month follow-up study to assess the possibility of synthesized nanocarriers to induce oxidative stress or DNA damage confirmed their safety for pre-clinical applications. 22Na-loaded nanocarriers can thus provide an innovative diagnostic agent allowing ultra-sensitive positron emission tomography imaging. On the other hand, with its long lifetime, onsite generators or cyclotrons will not be required as 22Na can be easily stored in the nuclear medicine department and be used on-demand. PMID:26504381

  7. The Silicon Photomultiplier for application to high-resolution Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Herbert, D. J.; Moehrs, S.; D'Ascenzo, N.; Belcari, N.; Del Guerra, A.; Morsani, F.; Saveliev, V.

    2007-04-01

    Positron Emission Tomography (PET) for small animal studies requires high-resolution gamma cameras with high sensitivity. Traditionally, inorganic scintillators are used and, in recent times, coupled to position sensitive PMTs to achieve a higher resolution. Such PSPMTs are costly, operated at high voltage and have a relatively low packing fraction. However, their advantage, compared to current solid state photodetectors, is their high signal-to-noise ratio. The Silicon Photomultiplier (SiPM) is a silicon diode detector that shows great promise as a photodetector for scintillators and hence application in nuclear medicine imaging applications. The microcell MRS (Metal-Resistor-Semiconductor) structure of the SiPM leads to a self-quenching, Geiger-mode avalanche photodiode (GAPD), that produces a large gain (5×105) at low bias voltage (50 V) and proportional output for moderate photon flux. Such a compact silicon detector, with a performance similar to a PMT, is obviously well disposed to being developed into a close-packed array in order to have a position-sensitive detection surface. We propose a miniature, high-resolution camera for a small-animal PET imaging system that is based on such an array of SiPM. The design is based upon the classic Anger camera principle; each detector module consists of a continuous slab of scintillator, viewed by a matrix of SiPM. A detector head of 4×4 cm2 in area is proposed, constructed from three such modules of the continuous camera described above. The stacked layers would give the system intrinsic depth of interaction (DOI) information. A summary of measured SiPM performance and results of a simulation of the proposed camera, using the Monte Carlo package GEANT4, are presented. It is shown that using three layers of 5 mm thick LSO, gives an efficiency of 68% with maximum count rates in the front layers. Intrinsic spatial resolution of <0.4 mm FWHM was found although this is degraded at the edges. Although the inclusion of DOI

  8. Preliminary safety evaluation of a cyclotron facility for positron emission tomography imaging.

    PubMed

    González, L; Vañó, E; Cordeiro, C A; Carreras, J L

    1999-08-01

    This work describes the design characteristics of a medical imaging centre which uses positron emission tomography, with a cyclotron for fluorine-18 and nitrogen-13 production, and which has provided experimental information on operational data recorded by area dosimetry since 1995. Doses to radiopharmacy and medical staff have been measured both in normal work and in some handling incidents. Data on radiation levels in the installation have also been obtained and related to design details and shielding. Area dosimetry was carried out using a five-stationary detector network, with a sampling rate of 2 min(-1), and by thermoluminescent dosimetry (TLD). Staff were also monitored by TLD, using extra chips for finger dosimetry and to duplicate individual whole-body dosimetry in order to measure doses in certain single operations. For normal work, average whole-body doses to radiopharmacy staff were between 0.03 and 0.28 mSv/month, wrist doses were between 0.42 and 2.67 mSv/month, and finger doses were between 1.4 and 7.7 mSv/day for the left hand and 0.8 and 2.4 mSv/day for the right hand; such variation reflects the differing expertise of staff and the role played by optimisation. Finger doses between 16 and 131 mSv were measured in handling incidents, and finger doses of 20.2 and 20.7 mSv for the left hand and 22.0 and 22.3 mSv for the right hand were measured during handling of a syringe without shielding, containing 3 GBq. For medical staff, contributions to the whole-body dose of 2.0 and 1.9 microSv/procedure were measured for injection and placing the patient on the examination couch, respectively. Dose measurement on the middle finger of the right hand gives an average of 70 microSv during the injection. The provisions regarding the shielding design have proved to be adequate and effective during a 3-year operational period. Operational doses to medical staff are comparatively low, while radiopharmacy staff are the most exposed. The finger doses in these

  9. Light illumination and detection patterns for fluorescence diffuse optical tomography based on compressive sensing.

    PubMed

    Jin, An; Yazici, Birsen; Ntziachristos, Vasilis

    2014-06-01

    Fluorescence diffuse optical tomography (FDOT) is an emerging molecular imaging modality that uses near infrared light to excite the fluorophore injected into tissue; and to reconstruct the fluorophore concentration from boundary measurements. The FDOT image reconstruction is a highly ill-posed inverse problem due to a large number of unknowns and limited number of measurements. However, the fluorophore distribution is often very sparse in the imaging domain since fluorophores are typically designed to accumulate in relatively small regions. In this paper, we use compressive sensing (CS) framework to design light illumination and detection patterns to improve the reconstruction of sparse fluorophore concentration. Unlike the conventional FDOT imaging where spatially distributed light sources illuminate the imaging domain one at a time and the corresponding boundary measurements are used for image reconstruction, we assume that the light sources illuminate the imaging domain simultaneously several times and the corresponding boundary measurements are linearly filtered prior to image reconstruction. We design a set of optical intensities (illumination patterns) and a linear filter (detection pattern) applied to the boundary measurements to improve the reconstruction of sparse fluorophore concentration maps. We show that the FDOT sensing matrix can be expressed as a columnwise Kronecker product of two matrices determined by the excitation and emission light fields. We derive relationships between the incoherence of the FDOT forward matrix and these two matrices, and use these results to reduce the incoherence of the FDOT forward matrix. We present extensive numerical simulation and the results of a real phantom experiment to demonstrate the improvements in image reconstruction due to the CS-based light illumination and detection patterns in conjunction with relaxation and greedy-type reconstruction algorithms.

  10. 18F-fluorodeoxyglucose positron emission tomography imaging in brain tumours: the Western Australia positron emission tomography/cyclotron service experience.

    PubMed

    McCarthy, M; Yuan, J B; Campbell, A; Lenzo, N P; Butler-Henderson, K

    2008-12-01

    (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in the first 49 patients referred with either possible brain tumour or brain tumour recurrence were reviewed. FDG-PET imaging was reported with reference to anatomical imaging. Based on the report the FDG study was classified as either positive or negative for the presence of tumour. Thirty-eight cases were included in the analysis, 21 having pathological data and 17 with diagnostic clinical follow up. Eleven were excluded, as they had inadequate follow-up data. Of the 21 cases with pathology, 18 were shown to have tumour. In this group there were five false-negative scans and two false-positive PET scans. Seventeen cases were assessed by clinical follow up, nine were considered to have been tumour. There were two false negatives with one false positive. The overall sensitivity, specificity and positive and negative predictive values were 74, 73, 87 and 53% respectively. This is similar to figures previously quoted in published work. Despite relatively limited numbers, the utility of FDG PET imaging in our hands is similar to published reports. With a positive predictive value of 87%, a positive FDG study indicates a high likelihood that there is brain tumour present. A negative study does not exclude the presence of tumour.

  11. Monte Carlo simulation of simultaneous radiation detection in the hybrid tomography system ClearPET-XPAD3/CT

    NASA Astrophysics Data System (ADS)

    Dávila, H. Olaya; Sevilla, A. C.; Castro, H. F.; Martínez, S. A.

    2016-07-01

    Using the Geant4 based simulation framework SciFW1, a detailed simulation was performed for a detector array in the hybrid tomography prototype for small animals called ClearPET / XPAD, which was built in the Centre de Physique des Particules de Marseille. The detector system consists of an array of phoswich scintillation detectors: LSO (Lutetium Oxy-ortosilicate doped with cerium Lu2SiO5:Ce) and LuYAP (Lutetium Ortoaluminate of Yttrium doped with cerium Lu0.7Y0.3AlO3:Ce) for Positron Emission Tomography (PET) and hybrid pixel detector XPAD for Computed Tomography (CT). Simultaneous acquisition of deposited energy and the corresponding time - position for each recorded event were analyzed, independently, for both detectors. interference between detection modules for PET and CT. Information about amount of radiation reaching each phoswich crystal and XPAD detector using a phantom in order to study the effectiveness by radiation attenuation and influence the positioning of the radioactive source 22Na was obtained. The simulation proposed will improve distribution of detectors rings and interference values will be taken into account in the new versions of detectors.

  12. Electrical impedance tomography for assessing ventilation/perfusion mismatch for pulmonary embolism detection without interruptions in respiration.

    PubMed

    Nguyen, Doan Trang; Thiagalingam, Aravinda; Bhaskaran, Abhishek; Barry, Michael A; Pouliopoulos, Jim; Jin, Craig; McEwan, Alistair L

    2014-01-01

    Recent studies have shown high correlation between pulmonary perfusion mapping with impedance contrast enhanced Electrical Impedance Tomography (EIT) and standard perfusion imaging methods such as Computed Tomography (CT) and Single Photon Emission Computerized Tomography (SPECT). EIT has many advantages over standard imaging methods as it is highly portable and non-invasive. Contrast enhanced EIT uses hypertonic saline bolus instead of nephrotoxic contrast medium that are utilized by CT and nuclear Ventilation/Perfusion (V/Q) scans. However, current implementation of contrast enhanced EIT requires induction of an apnea period for perfusion measurement, rendering it disadvantageous compared with current gold standard imaging modalities. In the present paper, we propose the use of a wavelet denoising algorithm to separate perfusion signal from ventilation signal such that no interruption in patient's ventilation would be required. Furthermore, right lung to left lung perfusion ratio and ventilation ratio are proposed to assess the mismatch between ventilation and perfusion for detection of Pulmonary Embolism (PE). The proposed methodology was validated on an ovine model (n=3, 83.7±7.7 kg) with artificially induced PE in the right lung. The results showed a difference in right lung to left lung perfusion ratio between baseline and diseased states in all cases with all paired t-tests between baseline and PE yielding p <; 0.01, while the right lung to left lung ventilation ratio remained unchanged in two out of three experiments. Statistics were pooled from multiple repetitions of measurements per experiment.

  13. Positron Emission Tomography for Neck Evaluation Following Definitive Treatment with Chemoradiotherapy for Locoregionally Advanced Head and Neck Squamous Cell Carcinoma

    PubMed Central

    Bar-Ad, Voichita; Mishra, Mark; Ohri, Nitin; Intenzo, Charles

    2013-01-01

    Objectives The objective of the current review was to assess published data on the role of Positron Emission Tomography (PET) for evaluation of nodal residual disease after definitive chemoradiotherapy for head and neck squamous cell carcinoma (HNSCC). Methods Studies were identified by searching PubMed electronic databases. Only studies using a post-chemoradiotherapy PET for nodal residual disease evaluation were included in the present review. Both prospective and retrospective studies were included. Information regarding sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET for detecting nodal residual disease after definitive chemoradiotherapy for HNSCC was extracted and analyzed. Results Twenty published studies were included in the present review. Existing data suggest that a negative post-chemoradiotherapy PET scan is associated with a negative predictive value up to 100%. The sensitivity of PET in detecting nodal residual disease is greater for scans performed ≥ 10 weeks after definitive treatment with chemoradiotherapy for HNSCC. Conclusions Further studies are needed to quantify the reliability of PET in detecting nodal residual disease after chemoradiotherapy for locoregionally advanced HNSCC. The optimal timing of PET imaging after chemoradiotherapy remains to be defined. PMID:21864252

  14. A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space.

    PubMed

    Montaño-Zetina, Luis Manuel; Villalobos-Mora, Omar

    2016-01-01

    A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was created by coupling plastic scintillator crystals to photomultipliers or PMT's which are placed at opposing positions to detect two gamma rays emitted from a radioactive source, of which is placed in the geometric center of the PET set-up. The prototype consists of four detectors placed geometrically in a 20 cm diameter circle, and a radioactive source in the center. By moving the radioactive source centimeters from the center the system one is able to detect the displacement by measuring the time of flight difference between any two PMT's and, with this information, the system can calculate the virtual position in a graphical interface. In this way, the prototype reproduces the main principles of a PET system. It is capable to determine the real position of the source with intervals of 4 cm in 2 lines of detection taking less than 2 min. PMID:26863081

  15. Repeated Positron Emission Tomography-Computed Tomography and Perfusion-Computed Tomography Imaging in Rectal Cancer: Fluorodeoxyglucose Uptake Corresponds With Tumor Perfusion

    SciTech Connect

    Janssen, Marco H.M.; Aerts, Hugo J.W.L.; Buijsen, Jeroen; Lambin, Philippe; Lammering, Guido; Oellers, Michel C.

    2012-02-01

    Purpose: The purpose of this study was to analyze both the intratumoral fluorodeoxyglucose (FDG) uptake and perfusion within rectal tumors before and after hypofractionated radiotherapy. Methods and Materials: Rectal cancer patients, referred for preoperative hypofractionated radiotherapy (RT), underwent FDG-positron emission tomography (PET)-computed tomography (CT) and perfusion-CT (pCT) imaging before the start of hypofractionated RT and at the day of the last RT fraction. The pCT-images were analyzed using the extended Kety model, quantifying tumor perfusion with the pharmacokinetic parameters K{sup trans}, v{sub e}, and v{sub p}. The mean and maximum FDG uptake based on the standardized uptake value (SUV) and transfer constant (K{sup trans}) within the tumor were correlated. Also, the tumor was subdivided into eight subregions and for each subregion the mean and maximum SUVs and K{sup trans} values were assessed and correlated. Furthermore, the mean FDG uptake in voxels presenting with the lowest 25% of perfusion was compared with the FDG uptake in the voxels with the 25% highest perfusion. Results: The mean and maximum K{sup trans} values were positively correlated with the corresponding SUVs ({rho} = 0.596, p = 0.001 and {rho} = 0.779, p < 0.001). Also, positive correlations were found for K{sup trans} values and SUVs within the subregions (mean, {rho} = 0.413, p < 0.001; and max, {rho} = 0.540, p < 0.001). The mean FDG uptake in the 25% highest-perfused tumor regions was significantly higher compared with the 25% lowest-perfused regions (10.6% {+-} 5.1%, p = 0.017). During hypofractionated radiotherapy, stable mean (p = 0.379) and maximum (p = 0.280) FDG uptake levels were found, whereas the mean (p = 0.040) and maximum (p = 0.003) K{sup trans} values were found to significantly increase. Conclusion: Highly perfused rectal tumors presented with higher FDG-uptake levels compared with relatively low perfused tumors. Also, intratumor regions with a high FDG

  16. 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.

  17. Detecting early stage osteoarthritis by optical coherence tomography?

    PubMed Central

    Jahr, Holger; Brill, Nicolai; Nebelung, Sven

    2015-01-01

    Abstract Osteoarthritis (OA) is the most common chronic disease of our joints, manifested by a dynamically increasing degeneration of hyaline articular cartilage (AC). While currently no therapy can reverse this process, the few available treatment options are hampered by the inability of early diagnosis. Loss of cartilage surface, or extracellular matrix (ECM), integrity is considered the earliest sign of OA. Despite the increasing number of imaging modalities surprisingly few imaging biomarkers exist. In this narrative review, recent developments in optical coherence tomography are critically evaluated for their potential to assess different aspects of AC quality as biomarkers of OA. Special attention is paid to imaging surface irregularities, ECM organization and the evaluation of posttraumatic injuries by light-based modalities. PMID:26862954

  18. Hybrid Positron Emission Tomography/Magnetic Resonance Imaging: Challenges, Methods, and State of the Art of Hardware Component Attenuation Correction.

    PubMed

    Paulus, Daniel H; Quick, Harald H

    2016-10-01

    Attenuation correction (AC) is an essential step in the positron emission tomography (PET) data reconstruction process to provide accurate and quantitative PET images. The introduction of PET/magnetic resonance (MR) hybrid systems has raised new challenges but also possibilities regarding PET AC. While in PET/computed tomography (CT) imaging, CT images can be converted to attenuation maps, MR images in PET/MR do not provide a direct relation to attenuation. For the AC of patient tissues, new methods have been suggested, for example, based on image segmentation, atlas registration, or ultrashort echo time MR sequences. Another challenge in PET/MR hybrid imaging is AC of hardware components that are placed in the PET/MR field of view, such as the patient table or various radiofrequency (RF) coils covering the body of the patient for MR signal detection. Hardware components can be categorized into 4 different groups: (1) patient table, (2) RF receiver coils, (3) radiation therapy equipment, and (4) PET and MR imaging phantoms. For rigid and stationary objects, such as the patient table and some RF coils like the head/neck coil, predefined CT-based attenuation maps stored on the system can be used for automatic AC. Flexible RF coils are not included into the AC process till now because they can vary in position as well as in shape and are not accurately detectable with the PET/MR system.This work summarizes challenges, established methods, new concepts, and the state of art in hardware component AC in the context of PET/MR hybrid imaging. The work also gives an overview of PET/MR hardware devices, their attenuation properties, and their effect on PET quantification. PMID:27175550

  19. Hybrid Positron Emission Tomography/Magnetic Resonance Imaging: Challenges, Methods, and State of the Art of Hardware Component Attenuation Correction.

    PubMed

    Paulus, Daniel H; Quick, Harald H

    2016-10-01

    Attenuation correction (AC) is an essential step in the positron emission tomography (PET) data reconstruction process to provide accurate and quantitative PET images. The introduction of PET/magnetic resonance (MR) hybrid systems has raised new challenges but also possibilities regarding PET AC. While in PET/computed tomography (CT) imaging, CT images can be converted to attenuation maps, MR images in PET/MR do not provide a direct relation to attenuation. For the AC of patient tissues, new methods have been suggested, for example, based on image segmentation, atlas registration, or ultrashort echo time MR sequences. Another challenge in PET/MR hybrid imaging is AC of hardware components that are placed in the PET/MR field of view, such as the patient table or various radiofrequency (RF) coils covering the body of the patient for MR signal detection. Hardware components can be categorized into 4 different groups: (1) patient table, (2) RF receiver coils, (3) radiation therapy equipment, and (4) PET and MR imaging phantoms. For rigid and stationary objects, such as the patient table and some RF coils like the head/neck coil, predefined CT-based attenuation maps stored on the system can be used for automatic AC. Flexible RF coils are not included into the AC process till now because they can vary in position as well as in shape and are not accurately detectable with the PET/MR system.This work summarizes challenges, established methods, new concepts, and the state of art in hardware component AC in the context of PET/MR hybrid imaging. The work also gives an overview of PET/MR hardware devices, their attenuation properties, and their effect on PET quantification.

  20. Thoracic [18F]fluorodeoxyglucose uptake measured by positron emission tomography/computed tomography in pulmonary hypertension.

    PubMed

    Frille, Armin; Steinhoff, Karen Geva; Hesse, Swen; Grachtrup, Sabine; Wald, Alexandra; Wirtz, Hubert; Sabri, Osama; Seyfarth, Hans-Juergen

    2016-06-01

    Positron emission tomography (PET) visualizes increased cellular [F]fluorodeoxyglucose ([F]FDG) uptake. Pulmonary hypertension (PH) is conceived of a proliferative disease of the lung vessels. Increased glucose uptake can be quantified as pulmonary [F]FDG uptake via PET imaging. Because the angioproliferative mechanisms in PH are still in need of further description, the aim of the present study was to investigate whether [F]FDG PET/CT imaging can elucidate these pathophysiologic mechanisms in different etiologies of PH.Patients (n = 109) with end-stage pulmonary disease being evaluated for lung transplant were included in this observational study. Mean standardized uptake value (SUVmean) of predefined regions of interest in lung parenchyma (LP), left (LV), and right ventricle (RV) of the heart, and SUVmax in pulmonary artery (PA) were determined and normalized to liver uptake. These SUV ratios (SUVRs) were compared with results from right heart catheterization (mean pulmonary artery pressure [mPAP], pulmonary vascular resistance [PVR]), and serum N-terminal pro-brain natriuretic peptide. Group comparisons were performed and Pearson correlation coefficients (r) were calculated.The [F]FDG uptake ratios in LP, RV, RV/LV, and PA, but not in LV, were found to be significantly higher in both patients with mPAP ≥25 mm Hg (P = 0.013, P = 0.006, P = 0.049, P = 0.002, P = 0.68, respectively) and with PVR ≥480 dyn·s/cm (P < 0.001, P = 0.045, P < 0.001, P < 0.001, P = 0.26, respectively). The [F]FDG uptake in these regions positively correlated also with mPAP, PVR, and N-terminal pro-brain natriuretic peptide. The SUVR of PA positively correlated with the SUVR of LP and RV (r = 0.55, r = 0.42, respectively).Pulmonary and cardiac [F]FDG uptake in PET imaging positively correlated with the presence and severity of PH in patients with end-stage pulmonary disease. Increased glucose metabolism in the central PAs seems to

  1. Comparison of Computed Tomography and Chest Radiography in the Detection of Rib Fractures in Abused Infants

    ERIC Educational Resources Information Center

    Wootton-Gorges, Sandra L.; Stein-Wexler, Rebecca; Walton, John W.; Rosas, Angela J.; Coulter, Kevin P.; Rogers, Kristen K.

    2008-01-01

    Purpose: Chest radiographs (CXR) are the standard method for evaluating rib fractures in abused infants. Computed tomography (CT) is a sensitive method to detect rib fractures. The purpose of this study was to compare CT and CXR in the evaluation of rib fractures in abused infants. Methods: This retrospective study included all 12 abused infants…

  2. Acoustic Emission tomography based on simultaneous algebraic reconstruction technique to visualize the damage source location in Q235B steel plate

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Xu, Feiyun; Xu, Bingsheng

    2015-12-01

    Acoustic Emission (AE) tomography based on Simultaneous Algebraic Reconstruction Technique (SART), which combines the traditional location algorithm with the SART algorithm by using AE events as its signal sources, is a new visualization method for inspecting and locating the internal damages in the structure. In this paper, the proposed method is applied to examine and visualize two man-made damage source locations in the Q235B steel plate to validate its effectiveness. Firstly, the Q235B steel plate with two holes specimen is fabricated and the pencil lead break (PLB) signal is taken as the exciting source for AE tomography.Secondly, A 6-step description of the SART algorithm is provided and the three dimensional(3D)image contained the damage source locations is visualized by using the proposed algorithm in terms of a locally varying wave velocity distribution. It is shown that the AE tomography based on SART has great potential in the application of structure damage detection. Finally, to further improve the quality of 3D imaging, the Median Filter and the Adaptive Median Filter are used to reduce the noises resulting from AE tomography. The experiment results indicate that Median Filter is the optimal method to remove Salt & Pepper noises.

  3. Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET)/MRI for Lung Cancer Staging.

    PubMed

    Ohno, Yoshiharu; Koyama, Hisanobu; Lee, Ho Yun; Yoshikawa, Takeshi; Sugimura, Kazuro

    2016-07-01

    Tumor, lymph node, and metastasis (TNM) classification of lung cancer is typically performed with the TNM staging system, as recommended by the Union Internationale Contre le Cancer (UICC), the American Joint Committee on Cancer (AJCC), and the International Association for the Study of Lung Cancer (IASLC). Radiologic examinations for TNM staging of lung cancer patients include computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography with 2-[fluorine-18] fluoro-2-deoxy-D-glucose (FDG-PET), and FDG-PET combined with CT (FDG-PET/CT) and are used for pretherapeutic assessments. Recent technical advances in MR systems, application of fast and parallel imaging and/or introduction of new MR techniques, and utilization of contrast media have markedly improved the diagnostic utility of MRI in this setting. In addition, FDG-PET can be combined or fused with MRI (PET/MRI) for clinical practice. This review article will focus on these recent advances in MRI as well as on PET/MRI for lung cancer staging, in addition to a discussion of their potential and limitations for routine clinical practice in comparison with other modalities such as CT, FDG-PET, and PET/CT.

  4. Measurement of human cerebral blood flow with (15O)butanol and positron emission tomography

    SciTech Connect

    Berridge, M.S.; Adler, L.P.; Nelson, A.D.; Cassidy, E.H.; Muzic, R.F.; Bednarczyk, E.M.; Miraldi, F. )

    1991-09-01

    Although H2(15)O is widely used for CBF measurement by positron tomography, it underestimates CBF, especially at elevated flow rates. Several tracers, including butanol, overcome this problem, but the short half-life of 15O provides advantages that cause water to remain the tracer of choice. The authors report the first use and evaluation of 15O-labeled butanol for CBF measurement. Flow measurements made in a similar fashion with water and butanol at 10-min intervals were compared in normal volunteers under resting and hypercapnic conditions. Regional analysis showed good agreement between the tracers at low flows, and significant underestimation of flow by water relative to butanol in regions of elevated flow. The observed relationship between the tracers and the curve-fitted permeability-surface area product for water (133 ml.100 g-1.min-1) follow the known relationship between water and true flow. These observations indicate that (15O)-butanol provided accurate measurements of human regional CBF under conditions of elevated perfusion. They conclude that butanol is a convenient and accurate method for routine CBF determination by positron emission tomography.

  5. A broad overview of positron emission tomography radiopharmaceuticals and clinical applications: what is new?

    PubMed

    Vallabhajosula, Shankar; Solnes, Lilja; Vallabhajosula, Brigitte

    2011-07-01

    Positron emission tomography (PET)/computed tomography (CT) is a rapidly expanding imaging modality, thanks to the availability of compact medical cyclotrons and automated chemistry synthesis modules for the production of PET radiopharmaceuticals. Despite the availability of many radiotracers, [(18)F]fluorodeoxyglucose (FDG) is currently the most widely used radiopharmaceutical in PET, and the field of molecular imaging is anxiously awaiting the introduction of new PET radiopharmaceuticals for routine clinical use. During the last five years, several proprietary PET radiopharmaceuticals have been developed by major companies, and these new agents are in different stages of clinical evaluation. These new PET drugs are designed for imaging brain beta amyloid, myocardial perfusion, amino acid transport, angiogenesis, and tumor antigen expression. In addition, the National Cancer Institute, Society of Nuclear Medicine Clinical Trials Network, and the American College of Radiology Imaging Network have been conducting multicenter clinical trials with several nonproprietary PET drugs such as sodium [(18)F]fluoride, [(18)F]fluorothymidine, [(18)F]fluoromisonidazole, and (64)Cu-labeled diacetyl-bis (N(4)-methylthiosemicarbazone. All new PET radiopharmaceuticals, like any other drugs, must be manufactured under current good manufacturing practices as required by the Food and Drug Administration before clinical evaluation (phases I, II, and III) and submission of new drug application. This review briefly describes the chemistry, mechanisms(s) of localization, and clinical application of both proprietary and nonproprietary new PET drugs under multicenter clinical evaluation.

  6. Positron emission tomography in aging and dementia: effect of cerebral atrophy

    SciTech Connect

    Chawluk, J.B.; Alavi, A.; Dann, R.; Hurtig, H.I.; Bais, S.; Kushner, M.J.; Zimmerman, R.A.; Reivich, M.

    1987-04-01

    The spatial resolution of current positron emission tomography (PET) scanners does not allow a distinction between cerebrospinal fluid (CSF) containing spaces and contiguous brain tissue. Data analysis strategies which therefore purport to quantify cerebral metabolism per unit mass brain tissue are in fact measuring a value which may be artifactually reduced due to contamination by CSF. We studied cerebral glucose metabolism (CMRglc) in 17 healthy elderly individuals and 24 patients with Alzheimer's dementia using (/sup 18/F)fluorodeoxyglucose and PET. All subjects underwent x-ray computed tomography (XCT) scanning at the time of their PET study. The XCT scans were analyzed volumetrically, in order to determine relative areas for ventricles, sulci, and brain tissue. Global CMRglc was calculated before and after correction for contamination by CSF (cerebral atrophy). A greater increase in global CMRglc after atrophy correction was seen in demented individuals compared with elderly controls (16.9% versus 9.0%, p less than 0.0005). Additional preliminary data suggest that volumetric analysis of proton-NMR images may prove superior to analysis of XCT data in quantifying the degree of atrophy. Appropriate corrections for atrophy should be employed if current PET scanners are to accurately measure actual brain tissue metabolism in various pathologic states.

  7. In vivo diagnosis of human malignant melanoma with positron emission tomography using specific melanoma-seeking 18F-DOPA analogue.

    PubMed

    Mishima, Y; Imahori, Y; Honda, C; Hiratsuka, J; Ueda, S; Ido, T

    1997-05-01

    Detection and diagnosis of human malignant melanoma by Positron Emission Tomography (PET) using 18F-10B-L-BPA, a specific melanogenesis-seeking compound synthesized for use in Boron Neutron Capture Therapy for malignant melanoma (NCT), has been developed. This resulted in a novel, highly effective methodology for the selective three dimensional imaging of metastatic malignant melanomas, and for accurate determination of 10B concentration in the tumor and surrounding tissue, providing almost all diagnostic information necessary for complete non-invasive radiation dose planning in the treatment of malignant melanoma both for NCT as well as other therapeutic modalities.

  8. Model-based respiratory motion compensation for emission tomography image reconstruction.

    PubMed

    Reyes, M; Malandain, G; Koulibaly, P M; González-Ballester, M A; Darcourt, J

    2007-06-21

    In emission tomography imaging, respiratory motion causes artifacts in lungs and cardiac reconstructed images, which lead to misinterpretations, imprecise diagnosis, impairing of fusion with other modalities, etc. Solutions like respiratory gating, correlated dynamic PET techniques, list-mode data based techniques and others have been tested, which lead to improvements over the spatial activity distribution in lungs lesions, but which have the disadvantages of requiring additional instrumentation or the need of discarding part of the projection data used for reconstruction. The objective of this study is to incorporate respiratory motion compensation directly into the image reconstruction process, without any additional acquisition protocol consideration. To this end, we propose an extension to the maximum likelihood expectation maximization (MLEM) algorithm that includes a respiratory motion model, which takes into account the displacements and volume deformations produced by the respiratory motion during the data acquisition process. We present results from synthetic simulations incorporating real respiratory motion as well as from phantom and patient data.

  9. The Use and Misuse of Positron Emission Tomography in Lung Cancer Evaluation

    PubMed Central

    Chang, Ching-Fei; Rashtian, Afshin; Gould, Michael K.

    2011-01-01

    Synopsis Positron emission tomography (PET) has been studied for a variety of indications in patients with known or suspected non-small cell lung cancer (NSCLC). In this review, we discuss the potential benefits and limitations of PET for characterizing lung nodules, staging the mediastinum, identifying occult distant metastasis, determining prognosis and treatment response, guiding plans for radiation therapy, restaging during and after treatment, and selecting targets for tissue sampling. (Table 1) Evidence from randomized, controlled trials supports the use of PET for initial staging in NSCLC, while lower quality evidence from studies of diagnostic accuracy and modeling studies supports the use of PET for characterizing lung nodules. For most other indications in NSCLC, additional studies are required to clarify the role of PET and determine who is most likely to benefit. PMID:22054883

  10. A deconvolution function for single photon emission computed tomography with constant attenuation

    SciTech Connect

    Tomitani, T.

    1986-02-01

    A shift-invariant spatial deconvolution function for single-photon-emission computerized tomography with constant attenuation is presented. Image reconstruction algorithm is similar to conventional convolution-back-projection algorithm except that exponential weight is applied in backprojection process. The deconvolution function was obtained as a solution of a generalized Schlomilch's integral equation. A method to solve the integral equation is described briefly. The present deconvolution function is incorporated with frequency roll-off and image resolution can be preset. At the extreme of ideal image reconstruction, the deconvolution function is identical to that deduced by Kim et al. and its Fourier transform was proved to be identical to the filter deduced by Tretiak and Delaney and Gullburg and Budinger. Variance of the reconstructed image was analyzed and some numerical results were given. The algorithm was tested with computer simulation.

  11. The Australian government's review of positron emission tomography: evidence-based policy-making in action.

    PubMed

    Ware, Robert E; Francis, Hilton W; Read, Kenneth E

    2004-06-21

    The Commonwealth Government constituted the Medicare Services Advisory Committee (MSAC) to implement its commitment to entrench the principles of evidence-based medicine in Australian clinical practice. With its recent review of positron emission tomography (PETReview), the Commonwealth intervened in an established MSAC process, and sanctioned the stated objective to restrict expenditure on the technology. In our opinion: The evaluation of evidence by PETReview was fundamentally compromised by a failure to meet the terms of reference, poor science, poor process and unique decision-making benchmarks. By accepting the recommendations of PETReview, the Commonwealth is propagating information which is not of the highest quality. The use of inferior-quality information for decision-making by doctors, patients and policy-makers is likely to harm rather than enhance healthcare outcomes. PMID:15200360

  12. Perfusion and thallium single photon emission computed tomography in herpes simplex encephalitis.

    PubMed

    De Deyn, P P; Van den Broucke, P W; Pickut, B A; Appel, B; Crols, R; Cras, P; Martin, J J

    1998-04-15

    This is the first report on 201thallium-single photon emission computed tomography (201Tl-SPECT) brain scan of a patient with herpes simplex encephalitis (HSE). The presented 201Tl-SPECT observations are correlated with 99mtechnetium hexamethylpropylene amine oxime (99mTc-HMPAO) perfusion SPECT and magnetic resonance imaging (MRI) findings. Brain 99mTc-HMPAO perfusion SPECT reveals a hyperperfusion in the right temporal lobe with extension to the parietal lobe and a hypoperfusion in the ipsilateral occipital lobe. 201Tl-SPECT shows a fixation in the right temporal lobe coinciding with the gadolinium enhancement on MRI. The right occipital lesion shown by gadolinium captation on MRI and hypoperfusion on 99mTc-HMPAO perfusion SPECT was not evident on the 201Tl SPECT. These findings could illustrate that the lesions might be different pathophysiologically.

  13. Application of mathematical removal of positron range blurring in Positron Emission Tomography

    SciTech Connect

    Haber, S.F.; Derenzo, S.E.; Uber, D.

    1990-04-01

    The range of positrons in tissue is an important limitation to the ultimate spatial resolution achievable in Positron Emission Tomography. In this work we applied a Fourier deconvolution technique to remove range blurring in images taken by the Donner 600-Crystal Positron Tomograph. Using phantom data, we found significant improvement in the image quality and the FWHM for both {sup 68}Ga and {sup 82}Rb. These were successfully corrected so that the images and FWHM almost matched those of {sup 18}F which has negligible positron range. However, statistical noise was increased by the deconvolution process and it was not practical to recover the full spatial resolution of the tomograph. 10 refs., 6 figs., 3 tabs.

  14. Application of mathematical removal of positron range blurring in positron emission tomography

    SciTech Connect

    Haber, S.F.; Derenzo, S.E.; Uber, D. )

    1990-06-01

    The range of positrons in tissue is an important limitation to the ultimate spatial resolution achievable in positron emission tomography. In this work the authors have applied a Fourier deconvolution technique to remove range blurring in images taken by the Donner 600-crystal positron tomograph. Using phantom data, the authors have found significant improvement in the image quality and the FWHM for both {sup 68}Ga and {sup 82}Rb. These were successfully corrected so that the images and FWHM almost matched those of {sup 18}F which has negligible positron range. However, statistical noise was increased by the deconvolution process and it was not practical to recover the full spatial resolution of the tomograph.

  15. An Application of Micro-channel Plate Photomultiplier Tube to Positron Emission Tomography.

    PubMed

    Kim, H; Chen, C-T; Frisch, H; Tang, F; Kao, C-M

    2012-01-01

    We are developing a Time-of-Flight Positron Emission Tomography detector using flat panel micro-channel plate photomultiplier tubes (MCP PMT). The high-speed waveform sampling data acquisition is adopted to exploit the fast time response of MCP PMT efficiently by using transmission-line readout scheme. To demonstrate the feasibility of the proposed detector, prototype detector modules were built using Photonis XP85022 MCP PMT, transmission-line board (TL), and high-speed waveform sampling electronics equipped with DRS4 chips. The MCP/TL module was coupled to single LYSO crystal, and experimental tests have been conducted in a coincidence setup to measure the responses to 511 keV annihilation photon. The details of the prototype module, experimental setup, and the preliminary results are presented and discussed.

  16. An Application of Micro-channel Plate Photomultiplier Tube to Positron Emission Tomography

    PubMed Central

    Kim, H.; Chen, C.-T.; Frisch, H.; Tang, F.; Kao, C.-M.

    2012-01-01

    We are developing a Time-of-Flight Positron Emission Tomography detector using flat panel micro-channel plate photomultiplier tubes (MCP PMT). The high-speed waveform sampling data acquisition is adopted to exploit the fast time response of MCP PMT efficiently by using transmission-line readout scheme. To demonstrate the feasibility of the proposed detector, prototype detector modules were built using Photonis XP85022 MCP PMT, transmission-line board (TL), and high-speed waveform sampling electronics equipped with DRS4 chips. The MCP/TL module was coupled to single LYSO crystal, and experimental tests have been conducted in a coincidence setup to measure the responses to 511 keV annihilation photon. The details of the prototype module, experimental setup, and the preliminary results are presented and discussed. PMID:23227135

  17. Regional cerebral glucose metabolic rate in human sleep assessed by positron emission tomography

    SciTech Connect

    Buchsbaum, M.S.; Wu, J.; Hazlett, E.; Sicotte, N.; Bunney, W.E. Jr. ); Gillin, J.C. )

    1989-01-01

    The cerebral metabolic rate of glucose was measured during nighttime sleep in 36 normal volunteers using positron emission tomography and fluorine-18-labeled 2-deoxyglucose (FDG). In comparison to waking controls, subjects given FDG during non-rapid eye movement (NREM) sleep showed about a 23% reduction in metabolic rate across the entire brain. This decrease was greater for the frontal than temporal or occipital lobes, and greater for basal ganglia and thalamus than cortex. Subjects in rapid eye movement (REM) sleep tended to have higher cortical metabolic rates than walking subjects. The cingulate gyrus was the only cortical structure to show a significant increase in glucose metabolic rate in REM sleep in comparison to waking. The basal ganglia were relatively more active on the right in REM sleep and symmetrical in NREM sleep.

  18. Receptor-specific positron emission tomography radiopharmaceuticals: /sup 75/Br-labeled butyrophenone neuroleptics

    SciTech Connect

    Moerlein, S.M.; Stoecklin, G.; Weinhard, K.; Pawlik, G.; Heiss, W.D.

    1985-11-01

    Cerebral dopaminergic D/sub 2/ receptors are involved in several common disease states, such as schizophrenia, Parkinson's disease, and Huntington's chorea. The use of radiolabeled D/sub 2/ receptor-binding ligands with positron emission tomography (PET) to noninvasively quantitate D/sub 2/ receptor densities thus has potential application in medicine. Butyrophenone neuroleptics have a high in vitro and in vivo binding affinity for cerebral D/sub 2/ receptors, and due to the useful chemical and nuclear decay properties of /sup 74/Br (76% ..beta../sup +/, half-life = 1.6 h), the authors have evaluated radiobrominated bromospiperone (BSP), brombenperidol (BBP), and bromperidol (BP) as radiopharmaceuticals for use with PET.

  19. Caffeine and human cerebral blood flow: A positron emission tomography study

    SciTech Connect

    Cameron, O.G.; Modell, J.G.; Hariharan, M. )

    1990-01-01

    Positron emission tomography (PET) was used to quantify the effect of caffeine on whole brain and regional cerebral blood flow (CBF) in humans. A mean dose of 250 mg of caffeine produced approximately a 30% decrease in whole brain CBF; regional differences in caffeine effect were not observed. Pre-caffeine CBF strongly influenced the magnitude of the caffeine-induced decrease. Caffeine decreased p{sub a}CO{sub 2} and increased systolic blood pressure significantly; the change in p{sub a}CO{sub 2} did not account for the change in CBF. Smaller increases in diastolic blood pressure, heart rate, plasma epinephrine and norepinephrine, and subjectively reported anxiety were also observed.

  20. 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

  1. Myelin imaging with C-11 labeled diphenylmethanol and positron emission tomography

    SciTech Connect

    Herscovitch, P.; Dischino, D.D.; Kilbourn, M.R.; Welch, M.J.; Raichle, M.E.

    1985-05-01

    The authors have recently studied several C-11-labeled radiopharmaceuticals for their suitability as myelin imaging agents with positron emission tomography (PET). C-11 diphenylmethanol (DPM) was selected on the basis of its in vivo metabolic stability and high extraction and lipophilicity. PET studies were performed in three normal subjects and in one patient with multiple sclerosis (MS). Myelin distribution was imaged following the bolus intravenous administration of 25-30 mCi of C-11 DPM. Sequential scans were obtained after radiotracer administration to measure the DPM distribution as a function of time. In addition, regional cerebral blood flow was measured after the bolus intravenous injection of 0-15 water. A tomographic slice through the centrum semiovale was used to obtain regional data for gray matter (GM) and white matter (WM).

  2. Initial characterization of a position-sensitive photodiode/BGO detector for PET (positron emission tomography)

    SciTech Connect

    Derenzo, S.E.; Moses, W.W.; Jackson, H.G.; Turko, B.T.; Cahoon, J.L.; Geyer, A.B.; Vuletich, T.

    1988-11-01

    We present initial results of a position-sensitive photodiode/BGO detector for high resolution, multi-layer positron emission tomography (PET). Position sensitivity is achieved by dividing the 3 mm /times/ 20 mm rectangular photosensitive area along the diagonal to form two triangular segments. Each segment was individually connected to a low-noise amplifier. The photodiodes and crystals were cooled to /minus/100/degree/C to reduce dark current and increase the BGO signal. With an amplifier peaking time of 17 ..mu..sec, the sum of the signals (511 keV photopeak) was 3200 electrons with a full width at half maximum (fwhm) of 750 electrons. The ratio of one signal to the sum determined the depth of interaction with a resolution of 11 mm fwhm. 27 refs., 7 figs.

  3. The nigrostriatal dopaminergic pathway in Wilson's disease studied with positron emission tomography.

    PubMed Central

    Snow, B J; Bhatt, M; Martin, W R; Li, D; Calne, D B

    1991-01-01

    Movement disorders, including Parkinsonism, are prominent features of neurological Wilson's disease (WD). This suggests there may be dysfunction of the nigrostriatal dopaminergic pathway. To explore this possibility, five patients were studied using positron emission tomography (PET) with 18F-6-fluorodopa (6FD), and magnetic resonance imaging (MRI). We calculated striatal 6FD uptake rate constants by a graphical method and compared the results with those of 18 normal subjects. It was found that four patients with symptoms all had abnormally low 6FD uptake, and the one asymptomatic patient had normal uptake. PET evidence for nigrostriatal dopaminergic dysfunction was present even after many years of penicillamine treatment. It is concluded that the nigrostriatal dopaminergic pathway is involved in neurological WD. Images PMID:1901347

  4. An 8×8 Row-Column Summing Readout Electronics for Preclinical Positron Emission Tomography Scanners.

    PubMed

    Shih, Y C; Sun, F W; Macdonald, L R; Otis, B P; Miyaoka, R S; McDougald, W; Lewellen, T K

    2009-10-24

    This work presents a row/column summing readout electronics for an 8×8 silicon photomultiplier array. The summation circuit greatly reduces the number of electronic channels, which is desirable for pursuing higher resolution positron emission tomography scanners. By using a degenerated common source topology in the summation circuit, more fan-in is possible and therefore a greater reduction in the number of electronic channels can be achieved. The timing signal is retrieved from a common anode, which allows the use of a single fast-sampling analog to digital converter (ADC) for the timing channel and slower, lower power ADCs for the 64 spatial channels. Preliminary results of one row summation of the 8×8 readout electronics exhibited FWHM energy resolution of 17.8% and 18.3% with and without multiplexing, respectively. The measured timing resolution is 2.9ns FWHM.

  5. Nicotine Blocks Brain Estrogen Synthase (Aromatase): In Vivo Positron Emission Tomography Studies in Female Baboons

    SciTech Connect

    Biegon, A.; Biegon, A.; Kim, S.-W.; Logan, J.; Hooker, J.M.; Muench, L.; Fowler, J.S.

    2010-01-12

    Cigarette smoking and nicotine have complex effects on human physiology and behavior, including some effects similar to those elicited by inhibition of aromatase, the last enzyme in estrogen biosynthesis. We report the first in vivo primate study to determine whether there is a direct effect of nicotine administration on brain aromatase. Brain aromatase availability was examined with positron emission tomography and the selective aromatase inhibitor [{sup 11}C]vorozole in six baboons before and after exposure to IV nicotine at .015 and .03 mg/kg. Nicotine administration produced significant, dose-dependent reductions in [{sup 11}C]vorozole binding. The amygdala and preoptic area showed the largest reductions. Plasma levels of nicotine and its major metabolite cotinine were similar to those found in cigarette smokers. Nicotine interacts in vivo with primate brain aromatase in regions involved in mood, aggression, and sexual behavior.

  6. Measurement of blood-brain barrier permeability with positron emission tomography and (68Ga)EDTA

    SciTech Connect

    Kessler, R.M.; Goble, J.C.; Bird, J.H.; Girton, M.E.; Doppman, J.L.; Rapoport, S.I.; Barranger, J.A.

    1984-09-01

    Positron emission tomography (PET) was employed to examine time-dependent changes in blood-brain barrier (BBB) permeability to (68Ga)ethylenediaminetetraacetate (EDTA) in the rhesus monkey, following reversible barrier opening by intracarotid infusion of a hypertonic mannitol solution. The PET technique, when combined with measurements of plasma radioactivity, provided a quantitative measure of the cerebrovascular permeability-area product (PA) at different times following mannitol infusion. Hypertonic mannitol treatment reversibly increased PA to (68Ga)EDTA more than 10-fold; much of the barrier effect was over by 10 min after mannitol treatment. The results show that PET can be used to measure transient changes in BBB integrity in specific brain regions, under in vivo, noninvasive conditions.

  7. Patterns of brain activity in normals and schizophrenics with positron emission tomography

    SciTech Connect

    Volkow, N.D.; Wolf, A.P.; Gomez-Mont, F.; Brodie, J.D.; Canero, R.; Van Gelder, P.; Russell, J.A.G.

    1985-05-01

    The authors investigated the functional interaction among brain areas under baseline and upon activation by a visual task to compare the response of normal subjects from the ones of chronic schizophrenics. Cerebral metabolic images were obtained on twelve healthy volunteers an eighteen schizophrenics with positron emission tomography and 11-C-Deoxyglucose. Correlation coefficients among the relative metabolic values (region of interest divided by the average of whole brain gray matter) of 11 brain regions; frontal, parietal, temporal and occipital left and right lobes, left and right basal ganglia and thalamus were computed for the baseline and for the task. Under baseline, normals showed more functional correlations than schizophrenics. Both groups showed a thalamo-occipital (positive) and thalamo-frontal (negative) interaction. The highest correlations among homologous brain areas were the frontal, occipital and basal ganglia.

  8. Sparse representation and dictionary learning penalized image reconstruction for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Chen, Shuhang; Liu, Huafeng; Shi, Pengcheng; Chen, Yunmei

    2015-01-01

    Accurate and robust reconstruction of the radioactivity concentration is of great importance in positron emission tomography (PET) imaging. Given the Poisson nature of photo-counting measurements, we present a reconstruction framework that integrates sparsity penalty on a dictionary into a maximum likelihood estimator. Patch-sparsity on a dictionary provides the regularization for our effort, and iterative procedures are used to solve the maximum likelihood function formulated on Poisson statistics. Specifically, in our formulation, a dictionary could be trained on CT images, to provide intrinsic anatomical structures for the reconstructed images, or adaptively learned from the noisy measurements of PET. Accuracy of the strategy with very promising application results from Monte-Carlo simulations, and real data are demonstrated.

  9. An 8×8 Row-Column Summing Readout Electronics for Preclinical Positron Emission Tomography Scanners

    PubMed Central

    Shih, Y. C.; Sun, F. W.; MacDonald, L. R.; Otis, B. P.; Miyaoka, R. S.; McDougald, W.; Lewellen, T. K.

    2010-01-01

    This work presents a row/column summing readout electronics for an 8×8 silicon photomultiplier array. The summation circuit greatly reduces the number of electronic channels, which is desirable for pursuing higher resolution positron emission tomography scanners. By using a degenerated common source topology in the summation circuit, more fan-in is possible and therefore a greater reduction in the number of electronic channels can be achieved. The timing signal is retrieved from a common anode, which allows the use of a single fast-sampling analog to digital converter (ADC) for the timing channel and slower, lower power ADCs for the 64 spatial channels. Preliminary results of one row summation of the 8×8 readout electronics exhibited FWHM energy resolution of 17.8% and 18.3% with and without multiplexing, respectively. The measured timing resolution is 2.9ns FWHM. PMID:20729983

  10. Positron emission tomography imaging as a key enabling technology in drug development.

    PubMed

    McCarthy, T J

    2007-01-01

    The use of positron emission tomography (PET) in drug development has become more common in the pharmaceutical industry in recent years. One of the biggest challenges to gaining acceptance of this technology is for project teams to understand when to use PET. This chapter reviews the usage of PET in drug development in the context of target, mechanism and efficacy biomarkers. Examples are drawn from a number of therapeutic areas, but we also show that the relative penetration of this technology beyond CNS and oncology applications has been relatively small. However, with the increasing availability of PET and development of novel radiotracers it is expected that the utilization will be much broader in future years, with the additional expectation that the use of PET as an efficacy biomarker will also become more evident. PMID:17172162

  11. Positron emission tomography radioligands for in vivo imaging of Aβ plaques

    PubMed Central

    Mason, N. Scott; Mathis, Chester A.; Klunk, William E.

    2014-01-01

    The development of positron emission tomography (PET) radioligands for the non-invasive imaging of amyloid-β plaque burden has been the focus of intense research efforts over the last decade. A variety of structural backbones have been investigated and several radiolabeled molecules have been evaluated in phase I (and later) clinical studies. These efforts have been driven by the desire not only to develop a suitable diagnostic imaging agent but also to develop a means to evaluate potential therapies for Alzheimer’s disease. This review focuses on the development of these ligands, as well as the radiochemistry and current regulatory status of these PET radioligands. Particular attention is given to those ligands that have progressed to the later stages of drug development (phase II/III clinical trial studies) or approved New Drug Application status. PMID:24285314

  12. Optical imaging of reporter gene expression using a positron-emission-tomography probe

    NASA Astrophysics Data System (ADS)

    Liu, Hongguang; Ren, Gang; Liu, Shuanglong; Zhang, Xiaofen; Chen, Luxi; Han, Peizhen; Cheng, Zhen

    2010-11-01

    Reporter gene/reporter probe technology is one of the most important techniques in molecular imaging. Lately, many reporter gene/reporter probe systems have been coupled to different imaging modalities such as positron emission tomography (PET) and optical imaging (OI). It has been recently found that OI techniques could be used to monitor radioactive tracers in vitro and in living subjects. In this study, we further demonstrate that a reporter gene/nuclear reporter probe system [herpes simplex virus type-1 thymidine kinase (HSV1-tk) and 9-(4-18F-fluoro-3-[hydroxymethyl] butyl) guanine ([18F]FHBG)] could be successfully imaged by OI in vitro and in vivo. OI with radioactive reporter probes will facilitate and broaden the applications of reporter gene/reporter probe techniques in medical research.

  13. Greater left cerebral hemispheric metabolism in bulimia assessed by positron emission tomography

    SciTech Connect

    Wu, J.C.; Hagman, J.; Buchsbaum, M.S.; Blinder, B.; Derrfler, M.; Tai, W.Y.; Hazlett, E.; Sicotte, N. )

    1990-03-01

    Eight women with bulimia and eight age- and sex-matched normal control subjects were studied with positron emission tomography using (18F)-fluorodeoxyglucose (FDG) as a tracer of brain metabolic rate. Subjects performed a visual vigilance task during FDG uptake. In control subjects, the metabolic rate was higher in the right hemisphere than in the left, but patients with bulimia did not have this normal asymmetry. Lower metabolic rates in the basal ganglia, found in studies of depressed subjects, and higher rates in the basal ganglia, reported in a study of anorexia nervosa, were not found. This is consistent with the suggestion that bulimia is a diagnostic grouping distinct from these disorders.

  14. 18-Fluorodeoxyglucose Uptake by Positron Emission Tomography in Extraocular Muscles of Patients with and without Graves' Ophthalmology

    PubMed Central

    García-Rojas, Leonardo; Adame-Ocampo, Gloria; Alexánderson, Erick; Tovilla-Canales, José Luis

    2013-01-01

    Objective. To compare 18-fluorodeoxyglucose (FDG) uptake by positron emission tomography (PET) in extraocular muscles (EOMs) of patients with Graves' ophthalmopathy (GO) versus patients without GO. Design. Prospective, observational, comparative, and cross-sectional study. Participants. Thirty-two eyes of patients with GO and seventy eyes of patients without GO. Methods. We prospectively included patients older than 18 years of age with and without GO. FDG-PET imaging study was performed; standardized unit value (SUVmax) was quantified in EOMs. Standard deviation and significant statistical difference (P < 0.05) were calculated. Results. Thirty-two eyes of sixteen patients of the GO group were included, with a mean age of 44.31 (20–71) years. Seventy eyes of thirty-five patients of the group without GO were included, with a mean age of 49.20 (24–77) years. EOMs average uptake of the groups with and without GO were 3.38 ± 1.31 and 1.89 ± 0.51 SUVmax (P < 0.05), respectively. Conclusion. FDG uptake was significantly increased in EOMs of patients with GO. PET gives valuable information and may be a helpful tool in detecting, localizing, and quantifying GO inflammation. Further research is needed to define the role of PET in detecting, grading, and following up GO in order to optimize treatment in the inflammatory stage. PMID:23476741

  15. Choice of reference area in studies of Alzheimer's disease using positron emission tomography with fluorodeoxyglucose-F18.

    PubMed

    Yakushev, Igor; Landvogt, Christian; Buchholz, Hans-Georg; Fellgiebel, Andreas; Hammers, Alexander; Scheurich, Armin; Schmidtmann, Irene; Gerhard, Alexander; Schreckenberger, Mathias; Bartenstein, Peter

    2008-11-30

    At present, there is still no consensus on the choice of the reference area in positron emission tomography (PET) studies of Alzheimer's disease (AD). In this study, PET scans with fluorodeoxyglucose-F18 were carried out in the following groups of subjects: 47 patients with probable AD, 8 patients with mild cognitive impairment, and 15 age-similar healthy subjects. Scans normalized to the cerebral global mean (CGM), cerebellum (CBL), and the primary sensorimotor cortex (SMC). We evaluated the effect of the different count normalization procedures on the accuracy of (18)F-FDG PET to detect AD-specific metabolic abnormalities (voxel-based group comparison) and to differentiate between patients and healthy subjects (ROI-based discriminant analysis) with regard to the degree of clinical deterioration. Metabolic reductions in groups of very mildly, mildly and moderate-to-severely affected patients appeared, respectively, 2.2, 2.6, and 2.7 times greater in spatial extent when tracer uptake was normalized to SMC rather than to CGM. The overall accuracy of discrimination was 94%, 91%, and 80% after normalization to SMC, CBL, and CGM, respectively. In general, normalization to SMC was somewhat superior to cerebellar normalization, allowing the detection of more pronounced metabolic deficits and the more accurate discrimination of patients from non-patients. Normalization to CGM should be used with great caution not only in advanced stages of dementia, but also in very mild AD cases. PMID:18930634

  16. Positron Emission Tomography of Brain β-Amyloid and Tau Levels in Adults With Down Syndrome

    PubMed Central

    Nelson, Linda D.; Siddarth, Prabha; Kepe, Vladimir; Scheibel, Kevin E.; Huang, S. C.; Barrio, Jorge R.; Small, Gary W.

    2012-01-01

    Objectives To determine the neuropathological load in the living brain of nondemented adults with Down syndrome using positron emission tomography with 2-(1-{6-[(2-fluorine 18–labeled fluoroethyl)methylamino]-2-napthyl}ethylidene) malononitrile ([18F]FDDNP) and to assess the influence of age and cognitive and behavioral functioning. For reference, [18F]FDDNP binding values and patterns were compared with those from patients with Alzheimer disease and cognitively intact control participants. Design Cross-sectional clinical study. Participants Volunteer sample of 19 persons with Down syndrome without dementia (mean age, 36.7 years), 10 patients with Alzheimer disease (mean age, 66.5 years), and 10 controls (mean age, 43.8 years). Main Outcome Measures Binding of [18F]FDDNP in brain regions of interest, including the parietal, medial temporal, lateral temporal, and frontal lobes and posterior cingulate gyrus, and the average of all regions (global binding). Results The [18F]FDDNP binding values were higher in all brain regions in the Down syndrome group than in controls. Compared with the Alzheimer disease group, the Down syndrome group had higher [18F]FDDNP binding values in the parietal and frontal regions, whereas binding levels in other regions were comparable. Within the Down syndrome group, age correlated with [18F]FDDNP binding values in all regions except the posterior cingulate, and several measures of behavioral dysfunction showed positive correlations with global, frontal, parietal, and posterior cingulate [18F]FDDNP binding. Conclusions Consistent with neuropathological findings from postmortem studies, [18F]FDDNP positron emission tomography shows high binding levels in Down syndrome comparable to Alzheimer disease and greater levels than in members of a control group. The positive associations between [18F]FDDNP binding levels and age as well as behavioral dysfunction in Down syndrome are consistent with the age-related progression of Alzheimer

  17. Predicting Outcome in Patients with Rhabdomyosarcoma: Role of [{sup 18}F]Fluorodeoxyglucose Positron Emission Tomography

    SciTech Connect

    Casey, Dana L.; Wexler, Leonard H.; Fox, Josef J.; Dharmarajan, Kavita V.; Schoder, Heiko; Price, Alison N.; Wolden, Suzanne L.

    2014-12-01

    Purpose: To evaluate whether [{sup 18}F]fluorodeoxyglucose positron emission tomography (FDG-PET) response of the primary tumor after induction chemotherapy predicts outcomes in rhabdomyosarcoma (RMS). Methods and Materials: After excluding those with initial tumor resection, 107 patients who underwent FDG-PET after induction chemotherapy at Memorial Sloan Kettering Cancer Center from 2002 to 2013 were reviewed. Local control (LC), progression-free survival (PFS), and overall survival (OS) were calculated according to FDG-PET response and maximum standardized uptake value (SUV) at baseline (PET1/SUV1), after induction chemotherapy (PET2/SUV2), and after local therapy (PET3/SUV3). Receiver operator characteristic curves were used to determine the optimal cutoff for dichotomization of SUV1 and SUV2 values. Results: The SUV1 (<9.5 vs ≥9.5) was predictive of PFS (P=.02) and OS (P=.02), but not LC. After 12 weeks (median) of induction chemotherapy, 45 patients had negative PET2 scans and 62 had positive scans: 3-year PFS was 72% versus 44%, respectively (P=.01). The SUV2 (<1.5 vs ≥1.5) was similarly predictive of PFS (P=.005) and was associated with LC (P=.02) and OS (P=.03). A positive PET3 scan was predictive of worse PFS (P=.0009), LC (P=.05), and OS (P=.03). Conclusions: [{sup 18}F]fluorodeoxyglucose positron emission tomography is an early indicator of outcomes in patients with RMS. Future prospective trials may incorporate FDG-PET response data for risk-adapted therapy and early assessment of new treatment regimens.

  18. Positron emission tomography demonstrates that coronary sinus retroperfusion can restore regional myocardial perfusion and preserve metabolism

    SciTech Connect

    O'Byrne, G.T.; Nienaber, C.A.; Miyazaki, A.; Araujo, L.; Fishbein, M.C.; Corday, E.; Schelbert, H.R. )

    1991-07-01

    Positron emission tomography was used to image blood flow and metabolic tracers in risk zone myocardium after left anterior descending coronary artery occlusion during synchronized coronary venous retroperfusion. Six control and seven intervention open chest dogs had occlusion of the mid left anterior descending coronary artery. Synchronized retroperfusion commenced 25 min later. Flow tracers (rubidium-82 and nitrogen-13 ammonia) were injected retrogradely. Three hours after coronary occlusion, fluorine-18 (F-18) deoxyglucose uptake in the control and treatment groups was compared. At 200 min of occlusion, infarct size was assessed. Retrograde flow tracer uptake was observed in the risk zone in the seven intervention dogs. Fluorine-18 deoxyglucose uptake in the risk zone was increased in five of the six intervention dogs but was reduced in five of the six control dogs. The risk zone to normal zone F-18 deoxyglucose count ratio was higher in the intervention than the control group (1.13 {plus minus} 0.39 vs. 0.59 {plus minus} 0.51; p less than 0.05). The endocardial subsegment risk zone to normal zone F-18 deoxyglucose count ratio was also significantly higher in the intervention group. Percent infarction in the risk zone was 70% lower in the group treated with synchronized retroperfusion than in the control group (18.4 {plus minus} 22.6% vs. 61.2 {plus minus} 25.4%; p less than 0.02). Thus, positron emission tomography revealed that retroperfusion could deliver oxygenated blood and maintain metabolism in risk zone myocardium. Infarct size was limited to 30% of that of control. In acute closure of the left anterior descending coronary artery, synchronized retroperfusion might be considered for maintaining viability of the jeopardized myocardium if the artery cannot be reopened rapidly.

  19. Regional myocardial metabolism in patients with acute myocardial infarction assessed by positron emission tomography

    SciTech Connect

    Schwaiger, M.; Brunken, R.; Grover-McKay, M.; Krivokapich, J.; Child, J.; Tillisch, J.H.; Phelps, M.E.; Schelbert, H.R.

    1986-10-01

    Positron emission tomography has been shown to distinguish between reversible and irreversible ischemic tissue injury. Using this technique, 13 patients with acute myocardial infarction were studied within 72 hours of onset of symptoms to evaluate regional blood flow and glucose metabolism with nitrogen (N)-13 ammonia and fluorine (F)-18 deoxyglucose, respectively. Serial noninvasive assessment of wall motion was performed to determine the prognostic value of metabolic indexes for functional tissue recovery. Segmental blood flow and glucose utilization were evaluated using a circumferential profile technique and compared with previously established semiquantitative criteria. Relative N-13 ammonia uptake was depressed in 32 left ventricular segments. Sixteen segments demonstrated a concordant decrease in flow and glucose metabolism. Regional function did not change over time in these segments. In contrast, 16 other segments with reduced blood flow revealed maintained F-18 deoxyglucose uptake consistent with remaining viable tissue. The average wall motion score improved significantly in these segments (p less than 0.01), yet the degree of recovery varied considerably among patients. Coronary anatomy was defined in 9 of 13 patients: patent infarct vessels supplied 8 of 10 segments with F-18 deoxyglucose uptake, while 10 of 13 segments in the territory of an occluded vessel showed concordant decreases in flow and metabolism (p less than 0.01). Thus, positron emission tomography reveals a high incidence of residual tissue viability in ventricular segments with reduced flow and impaired function during the subacute phase of myocardial infarction. Absence of residual tissue metabolism is associated with irreversible injury, while preservation of metabolic activity identifies segments with a variable outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Quantitative evaluation of benzodiazepine receptors in live Papio papio baboons using positron emission tomography

    SciTech Connect

    Brouillet, E.; Chavoix, C.; Khalili-Varasteh, M.; Bottlaender, M.; Hantraye, P.; Yorke, J.C.; Maziere, M. )

    1990-10-01

    The binding of the 11C-labeled benzodiazepine antagonist Ro 15-1788 (flumazenil) was measured in the neocortex of live Papio papio baboons by positron emission tomography. This allowed us to calculate in vivo (i.e., at physiological temperature, neurotransmitters concentrations, and ionic environment) the apparent density of available benzodiazepine receptors (B'max) and the dissociation constant of Ro 15-1788 (Kd). By coadministering increasing doses of unlabeled Ro 15-1788 with (11C)Ro 15-1788 and assuming that nonsaturable radioactivity indicated the free ligand concentration, we were able to obtain saturation isotherms. We showed that a state of quasiequilibrium was reached 50 min after the administration of the radioligand. Linear Scatchard plots allowed us to calculate B'max at 78 and 50 pmol/ml of cerebral tissue in the occipital and frontal cortices, respectively. In both these areas, Kd is on the order of 6 nM, with a Hill number very close to unity. This indicates that Ro 15-1788 binds in vivo with high affinity to an homogeneous population of saturable sites. A similar measurement was carried out on a naturally photosensitive P. papio baboon. Absolute values of B'max, Kd, and Hill number were similar to those of the control baboons. Although results concerning this baboon can only be considered as a case report, this similarity may suggest that its epileptic syndrome is not related to a large change in B'max or Kd, at least in occipital and frontal cortices. Our results showed that quantitative estimation by positron emission tomography of some characteristics of benzodiazepine receptors is possible in live baboons and may represent a supplementary tool for investigating further the molecular mechanisms of benzodiazepine receptor function in physiological and physiopathological conditions.

  1. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    PubMed

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted.

  2. 76 FR 54473 - Guidance on Positron Emission Tomography Drug Applications-Content and Format for New Drug...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ..., 2011 (76 FR 6143), and Docket No. FDA- 2000-D-1542 was open for comments until April 4, 2011. The... Emission Tomography Drug Products,'' issued on March 10, 2000 (65 FR 13010). The February 3, 2011, revised...-- Content and Format for New Drug Applications and Abbreviated New Drug Applications; Availability...

  3. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    PubMed

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. PMID:27245647

  4. Feature-space assessment of electrical impedance tomography coregistered with computed tomography in detecting multiple contrast targets

    SciTech Connect

    Krishnan, Kalpagam; Liu, Jeff; Kohli, Kirpal

    2014-06-15

    Purpose: Fusion of electrical impedance tomography (EIT) with computed tomography (CT) can be useful as a clinical tool for providing additional physiological information about tissues, but requires suitable fusion algorithms and validation procedures. This work explores the feasibility of fusing EIT and CT images using an algorithm for coregistration. The imaging performance is validated through feature space assessment on phantom contrast targets. Methods: EIT data were acquired by scanning a phantom using a circuit, configured for injecting current through 16 electrodes, placed around the phantom. A conductivity image of the phantom was obtained from the data using electrical impedance and diffuse optical tomography reconstruction software (EIDORS). A CT image of the phantom was also acquired. The EIT and CT images were fused using a region of interest (ROI) coregistration fusion algorithm. Phantom imaging experiments were carried out on objects of different contrasts, sizes, and positions. The conductive medium of the phantoms was made of a tissue-mimicking bolus material that is routinely used in clinical radiation therapy settings. To validate the imaging performance in detecting different contrasts, the ROI of the phantom was filled with distilled water and normal saline. Spatially separated cylindrical objects of different sizes were used for validating the imaging performance in multiple target detection. Analyses of the CT, EIT and the EIT/CT phantom images were carried out based on the variations of contrast, correlation, energy, and homogeneity, using a gray level co-occurrence matrix (GLCM). A reference image of the phantom was simulated using EIDORS, and the performances of the CT and EIT imaging systems were evaluated and compared against the performance of the EIT/CT system using various feature metrics, detectability, and structural similarity index measures. Results: In detecting distilled and normal saline water in bolus medium, EIT as a stand

  5. Facile synthesis, pharmacokinetic and systemic clearance evaluation, and positron emission tomography cancer imaging of 64Cu-Au alloy nanoclusters

    NASA Astrophysics Data System (ADS)

    Zhao, Yongfeng; Sultan, Deborah; Detering, Lisa; Luehmann, Hannah; Liu, Yongjian

    2014-10-01

    Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal biodistribution and significant renal and hepatobiliary excretion. PET imaging showed low non-specific tumor uptake, indicating its potential for active targeting of clinically relevant biomarkers in tumor and metastatic organs.Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal

  6. Inner structure detection by optical tomography technology based on feedback of microchip Nd:YAG lasers.

    PubMed

    Xu, Chunxin; Zhang, Shulian; Tan, Yidong; Zhao, Shijie

    2013-05-20

    We describe a new optical tomography technology based on feedback of microchip Nd:YAG lasers. In the case of feedback light frequency-shifted, light can be magnified by a fact of 10(6) in the Nd:YAG microchip lasers, which makes it possible to realize optical tomography with a greater depth than current optical tomography. The results of the measuring and imaging of kinds of samples are presented, which demonstrate the feasibility and potential of this approach in the inner structure detection. The system has a lateral resolution of ~1 μm, a vertical resolution of 15 μm and a longitudinal scanning range of over 10mm.

  7. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4.

    PubMed

    Agasthya, G A; Harrawood, B C; Shah, J P; Kapadia, A J

    2012-01-01

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g(-1), corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g(-1) and sensitivity is ∼13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g(-1) and ∼5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  8. Sensitivity analysis for liver iron measurement through neutron stimulated emission computed tomography: a Monte Carlo study in GEANT4

    NASA Astrophysics Data System (ADS)

    Agasthya, G. A.; Harrawood, B. C.; Shah, J. P.; Kapadia, A. J.

    2012-01-01

    Neutron stimulated emission computed tomography (NSECT) is being developed as a non-invasive imaging modality to detect and quantify iron overload in the human liver. NSECT uses gamma photons emitted by the inelastic interaction between monochromatic fast neutrons and iron nuclei in the body to detect and quantify the disease. Previous simulated and physical experiments with phantoms have shown that NSECT has the potential to accurately diagnose iron overload with reasonable levels of radiation dose. In this work, we describe the results of a simulation study conducted to determine the sensitivity of the NSECT system for hepatic iron quantification in patients of different sizes. A GEANT4 simulation of the NSECT system was developed with a human liver and two torso sizes corresponding to small and large patients. The iron concentration in the liver ranged between 0.5 and 20 mg g-1,In this paper all iron concentrations with units mg g-1 refer to wet weight concentrations. corresponding to clinically reported iron levels in iron-overloaded patients. High-purity germanium gamma detectors were simulated to detect the emitted gamma spectra, which were background corrected using suitable water phantoms and analyzed to determine the minimum detectable level (MDL) of iron and the sensitivity of the NSECT system. These analyses indicate that for a small patient (torso major axis = 30 cm) the MDL is 0.5 mg g-1 and sensitivity is ˜13 ± 2 Fe counts/mg/mSv and for a large patient (torso major axis = 40 cm) the values are 1 mg g-1 and ˜5 ± 1 Fe counts/mg/mSv, respectively. The results demonstrate that the MDL for both patient sizes lies within the clinically significant range for human iron overload.

  9. Impact of technology on the utilisation of positron emission tomography in lymphoma: current and future perspectives.

    PubMed

    Visvikis, D; Ell, P J

    2003-06-01

    Positron emission tomography (PET) has now gained a place in the management of patients with cancer, including those with Hodgkin's disease and non-Hodgkin's lymphoma. Restaging studies and those addressing the monitoring of response to treatment are especially in focus. Most of the knowledge gained has been achieved with dedicated BGO-based PET technology, but there are a number of developments that will impact on the use of this metabolic imaging technique in the investigation of patients with lymphoma. The challenges ahead are determined by the need for high-quality whole-body imaging associated with increased patient throughput and the need to investigate the role of new labelled ligands. The latter are likely to yield new insights into tumour cell characterisation, tumour behaviour and tumour outcome assessment. The study of new radiolabelled ligands will impose further demands for rapid dynamic data acquisition and accurate tracer quantification. Current and future developments in PET technology range from the use of new detector materials to different detector geometries and data acquisition modes. The search for alternatives to BGO scintillation materials for PET has led to the development of PET instruments utilising new crystals such as LSO and GSO. The use of these new detectors and the increased sensitivity achieved with 3D data acquisitions represent the most significant current developments in the field. With the increasing demands imposed on the clinical utilisation of PET, issues such as study cost and patient throughput will emerge as significant future factors. As a consequence, low-cost units are being offered by the manufacturers through the utilisation of gamma camera-based SPET systems for PET coincidence imaging. Unfortunately, clinical studies in lymphoma and other cancers have already demonstrated the limitations of this technology, with 20% of lesions <15 mm in size escaping detection. On the other hand, the recent development of combined

  10. Diffuse light tomography to detect blood vessels using Tikhonov regularization

    NASA Astrophysics Data System (ADS)

    Kazanci, Huseyin O.; Jacques, Steven L.

    2016-04-01

    Detection of blood vessels within light-scattering tissues involves detection of subtle shadows as blood absorbs light. These shadows are diffuse but measurable by a set of source-detector pairs in a spatial array of sources and detectors on the tissue surface. The measured shadows can reconstruct the internal position(s) of blood vessels. The tomographic method involves a set of Ns sources and Nd detectors such that Nsd = Ns x Nd source-detector pairs produce Nsd measurements, each interrogating the tissue with a unique perspective, i.e., a unique region of sensitivity to voxels within the tissue. This tutorial report describes the reconstruction of the image of a blood vessel within a soft tissue based on such source-detector measurements, by solving a matrix equation using Tikhonov regularization. This is not a novel contribution, but rather a simple introduction to a well-known method, demonstrating its use in mapping blood perfusion.

  11. Computed Tomography Features of Incidentally Detected Diffuse Thyroid Disease

    PubMed Central

    Rho, Myung Ho

    2014-01-01

    Objective. This study aimed to evaluate the CT features of incidentally detected DTD in the patients who underwent thyroidectomy and to assess the diagnostic accuracy of CT diagnosis. Methods. We enrolled 209 consecutive patients who received preoperative neck CT and subsequent thyroid surgery. Neck CT in each case was retrospectively investigated by a single radiologist. We evaluated the diagnostic accuracy of individual CT features and the cut-off CT criteria for detecting DTD by comparing the CT features with histopathological results. Results. Histopathological examination of the 209 cases revealed normal thyroid (n = 157), Hashimoto thyroiditis (n = 17), non-Hashimoto lymphocytic thyroiditis (n = 34), and diffuse hyperplasia (n = 1). The CT features suggestive of DTD included low attenuation, inhomogeneous attenuation, increased glandular size, lobulated margin, and inhomogeneous enhancement. ROC curve analysis revealed that CT diagnosis of DTD based on the CT classification of “3 or more” abnormal CT features was superior. When the “3 or more” CT classification was selected, the sensitivity, specificity, positive and negative predictive values, and accuracy of CT diagnosis for DTD were 55.8%, 95.5%, 80.6%, 86.7%, and 85.6%, respectively. Conclusion. Neck CT may be helpful for the detection of incidental DTD. PMID:25548565

  12. A rare tumor with unusual clinical presentation detected by positron emission tomography-computed tomography

    PubMed Central

    Patel, Sitendu Kumar; Shera, Irfan Ali

    2015-01-01

    Primary hepatic lymphoma represents <1% of extranodal lymphoma and predominantly seen in men older than 50 years of age. Exact etiology for these tumors is not certain yet, but presumed to be caused by certain viruses like Epstein-Barr virus and hepatitis C virus due to the frequent association of these viruses with disease. Most of these tumors are diffuse large B cell non-Hodgkin lymphoma. Direct tissue histopathology with immunochemistry may give clues about diagnosis and prognosis up to certain extent. The rituximab-based chemotherapy is the mainstay of therapy for these tumors; the role of radiotherapy is still not clear but used for management for bulky tumors. PMID:26430318

  13. Exact and approximative imaging methods for photoacoustic tomography using an arbitrary detection surface.

    PubMed

    Burgholzer, Peter; Matt, Gebhard J; Haltmeier, Markus; Paltauf, Günther

    2007-04-01

    Two universal reconstruction methods for photoacoustic (also called optoacoustic or thermoacoustic) computed tomography are derived, applicable to an arbitrarily shaped detection surface. In photoacoustic tomography acoustic pressure waves are induced by illuminating a semitransparent sample with pulsed electromagnetic radiation and are measured on a detection surface outside the sample. The imaging problem consists in reconstructing the initial pressure sources from those measurements. The first solution to this problem is based on the time reversal of the acoustic pressure field with a second order embedded boundary method. The pressure on the arbitrarily shaped detection surface is set to coincide with the measured data in reversed temporal order. In the second approach the reconstruction problem is solved by calculating the far-field approximation, a concept well known in physics, where the generated acoustic wave is approximated by an outgoing spherical wave with the reconstruction point as center. Numerical simulations are used to compare the proposed universal reconstruction methods with existing algorithms.

  14. A range muon tomography performance study for the detection of explosives

    SciTech Connect

    Cuellar, Leticia; Borozdin, Konstantin N; Chung, Andrew; Nicolas, Hengartner W; Morris, Christopher; Schultz, Larry J; Reimus, Nathaniel P; Bacon, Jeffrey D; Vogan - Mc Neil, Wendy

    2010-01-01

    Soft cosmic ray tomography has been shown to successfully discriminate materials with various density levels due to their ability to deeply penetrate matter, allowing sensitivity to atomic number, radiation length and density. Because the multiple muon scattering signal from high Z-materials is very strong, the technology is well suited to the detection of the illicit transportation of special and radiological nuclear materials. In addition, a recent detection technique based on measuring the lower energy particles that do not traverse the material (range radiography), allows to discriminate low and medium Z-materials. This is shown in [4] using Monte Carlo simulations. More recently, using a mini muon tracker developed at Los Alamos National Laboratory, we performed various experiments to try out the radiation length technology. This paper presents the results from real experiments and evaluates the likelihood that soft cosmic ray tomography may be applied to detect high-explosives.

  15. Clinical evaluation of a high-resolution (2. 6-mm) positron emission tomography

    SciTech Connect

    Valk, P.E.; Jagust, W.J.; Derenzo, S.E.; Huesman, R.H.; Geyer, A.B.; Budinger, T.F. )

    1990-09-01

    The intrinsic resolution of the Donner 600-crystal positron emission tomograph (PET 600) is 2.6 mm full width at half maximum (FWHM) in-plane and 6 mm FWHM axially. More than 100 patients with glioma, radiation necrosis, Alzheimer disease, or epilepsy have been studied with this system. Approximately 1 million events are acquired in 15 minutes, starting 1 hour after injection of 10 mCi (370 MBq) of fluorine-18-fluorodeoxyglucose. Normal structures as small as the superior colliculi and the external capsule have been resolved. Improved separation of the cortical ribbon from adjacent white matter has allowed more accurate determination of cortical metabolic rate. In two of 15 patients undergoing evaluation for recurrent glioma, the PET 600 images showed tumor uptake that was not apparent on a lower-resolution study. A high-activity orbiting transmission source with electronic collimation allows accurate, short-duration transmission measurements to be made after radiopharmaceutical administration. The anatomic detail seen on the transmission images can be used for reproducible patient positioning with an accuracy of 1-2 mm perpendicular to the image plane. These findings demonstrate the practicality and clinical effectiveness of high-resolution positron emission tomography.

  16. Clustering-initiated factor analysis application for tissue classification in dynamic brain positron emission tomography

    PubMed Central

    Boutchko, Rostyslav; Mitra, Debasis; Baker, Suzanne L; Jagust, William J; Gullberg, Grant T

    2015-01-01

    The goal is to quantify the fraction of tissues that exhibit specific tracer binding in dynamic brain positron emission tomography (PET). It is achieved using a new method of dynamic image processing: clustering-initiated factor analysis (CIFA). Standard processing of such data relies on region of interest analysis and approximate models of the tracer kinetics and of tissue properties, which can degrade accuracy and reproducibility of the analysis. Clustering-initiated factor analysis allows accurate determination of the time–activity curves and spatial distributions for tissues that exhibit significant radiotracer concentration at any stage of the emission scan, including the arterial input function. We used this approach in the analysis of PET images obtained using 11C-Pittsburgh Compound B in which specific binding reflects the presence of β-amyloid. The fraction of the specific binding tissues determined using our approach correlated with that computed using the Logan graphical analysis. We believe that CIFA can be an accurate and convenient tool for measuring specific binding tissue concentration and for analyzing tracer kinetics from dynamic images for a variety of PET tracers. As an illustration, we show that four-factor CIFA allows extraction of two blood curves and the corresponding distributions of arterial and venous blood from PET images even with a coarse temporal resolution. PMID:25899294

  17. Determination of the spatial characteristics of an RF electrodeless discharge by the method of emission tomography

    SciTech Connect

    Denisova, N. V.; Revalde, G.; Skudra, A.

    2006-11-15

    The spatial distribution of the density of mercury atoms in the 7{sup 3}S state in a spherical RF electrode-less gas-discharge lamp is reconstructed by the method of emission tomography. The local values of the corresponding emission coefficients, which are proportional to the density of mercury atoms in the 7{sup 3}S state, are determined from integral (over the plasma volume) measurements of the lamp radiation at a wavelength of 546.1 nm with the help of an algorithm based on the maximum entropy method. The results obtained show that, for all of the operating modes under study, the profile of the density of mercury atoms in the 7{sup 3}S state has a minimum in the center of the lamp and a maximum near its wall. At a generator current of 100 mA and cold-spot temperature of 41 deg. C, the density of mercury atoms in the 7{sup 3}S state is observed to drop substantially both in the center of the lamp and near its wall, the density in the center being reduced to almost zero. An explanation of this phenomenon is proposed.

  18. Molecular detectability in exoplanetary emission spectra

    NASA Astrophysics Data System (ADS)

    Tessenyi, M.; Tinetti, G.; Savini, G.; Pascale, E.

    2013-11-01

    Of the many recently discovered worlds orbiting distant stars, very little is yet known of their chemical composition. With the arrival of new transit spectroscopy and direct imaging facilities, the question of molecular detectability as a function of signal-to-noise (SNR), spectral resolving power and type of planets has become critical. In this paper, we study the detectability of key molecules in the atmospheres of a range of planet types, and report on the minimum detectable abundances at fixed spectral resolving power and SNR. The planet types considered-hot Jupiters, hot super-Earths, warm Neptunes, temperate Jupiters and temperate super-Earths-cover most of the exoplanets characterisable today or in the near future. We focus on key atmospheric molecules, such as CH4, CO, CO2, NH3, H2O, C2H2, C2H6, HCN, H2S and PH3. We use two methods to assess the detectability of these molecules: a simple measurement of the deviation of the signal from the continuum, and an estimate of the level of confidence of a detection through the use of the likelihood ratio test over the whole spectrum (from 1 to 16 μm). We find that for most planetary cases, SNR = 5 at resolution R = 300 (λ < 5 μm) and R = 30 (λ > 5 μm) is enough to detect the very strongest spectral features for the most abundant molecules, whereas an SNR comprised between 10 and 20 can reveal most molecules with abundances 10-6 or lower, often at multiple wavelengths. We test the robustness of our results by exploring sensitivity to parameters such as vertical thermal profile, mean molecular weight of the atmosphere and relative water abundances. We find that our main conclusions remain valid except for the most extreme cases. Our analysis shows that the detectability of key molecules in the atmospheres of a variety of exoplanet cases is within realistic reach, even with low SNR and spectral resolving power.

  19. DETECTION OF RADIO EMISSION FROM FIREBALLS

    SciTech Connect

    Obenberger, K. S.; Taylor, G. B.; Dowell, J.; Henning, P. A.; Schinzel, F. K.; Stovall, K.; Hartman, J. M.; Ellingson, S. W.; Helmboldt, J. F.; Wilson, T. L.; Kavic, M.; Simonetti, J. H.

    2014-06-20

    We present the findings from the Prototype All-Sky Imager, a back end correlator of the first station of the Long Wavelength Array, which has recorded over 11,000 hr of all-sky images at frequencies between 25 and 75 MHz. In a search of this data for radio transients, we have found 49 long-duration (10 s of seconds) transients. Ten of these transients correlate both spatially and temporally with large meteors (fireballs), and their signatures suggest that fireballs emit a previously undiscovered low frequency, non-thermal pulse. This emission provides a new probe into the physics of meteors and identifies a new form of naturally occurring radio transient foreground.

  20. Research instrumentation for tornado electromagnetics emissions detection

    NASA Technical Reports Server (NTRS)

    Jenkins, H. H.; Wilson, C. S.

    1977-01-01

    Instrumentation for receiving, processing, and recording HF/VHF electromagnetic emissions from severe weather activity is described. Both airborne and ground-based instrumentation units are described on system and subsystem levels. Design considerations, design decisions, and the rationale behind the decisions are given. Performance characteristics are summarized and recommendations for improvements are given. The objectives, procedures, and test results of the following are presented: (1) airborne flight test in the Midwest U.S.A. (Spring 1975) and at the Kennedy Space Center, Florida (Summer 1975); (2) ground-based data collected in North Georgia (Summer/Fall 1975); and (3) airborne flight test in the Midwest (late Spring 1976) and at the Kennedy Space Center, Florida (Summer 1976). The Midwest tests concentrated on severe weather with tornadic activity; the Florida and Georgia tests monitored air mass convective thunderstorm characteristics. Supporting ground truth data from weather radars and sferics DF nets are described.