Bulk and track etching of PET studied by spectrophotometer

International Nuclear Information System (INIS)

Zhu, Z.Y.; Duan, J.L.; Maekawa, Y.; Koshikawa, H.; Yoshida, M.

2004-01-01

UV-VIS spectra of poly(ethylene terephthalate) (PET) solutions formed by etching PET in NaOH solution were analyzed with respect to the etching time. A linear relationship between absorptions centered at 4.45 and 5.11 eV with weight loss of PET in NaOH solution was established. The relation was applied to study the influence of UV light illumination on bulk etching of PET and to evaluate pore size of etched-through tracks. It is found that bulk etching of PET can be greatly enhanced by UV illumination in air in the wavelength range around 313 nm. A surface area of about 350 nm in thickness shows a 23 times increase in bulk-etching rate after illuminated for 6 h. The phenomenon is attributed to the oxygen-assisted photo-degradation through generating of new photo-unstable species. The enhancement in bulk etching was immediately reduced as the etching proceeds below the surface with an exponential decay constant of about 1.5 μm -1 . Etching of Xe ion irradiated PET films gives extra etching products with similar chemical structure as revealed by spectrophotometer measurements. Quantitative analysis of etching products from latent tracks implies that pores of about 14.6 nm in radius are formed after etching in 0.74 N NaOH at 40 deg. C for 35 min, which is in agreement with the conductometric measurement

Evaluation of PeneloPET Simulations of Biograph PET/CT Scanners

Science.gov (United States)

Abushab, K. M.; Herraiz, J. L.; Vicente, E.; Cal-González, J.; España, S.; Vaquero, J. J.; Jakoby, B. W.; Udías, J. M.

2016-06-01

Monte Carlo (MC) simulations are widely used in positron emission tomography (PET) for optimizing detector design, acquisition protocols, and evaluating corrections and reconstruction methods. PeneloPET is a MC code based on PENELOPE, for PET simulations which considers detector geometry, acquisition electronics and materials, and source definitions. While PeneloPET has been successfully employed and validated with small animal PET scanners, it required a proper validation with clinical PET scanners including time-of-flight (TOF) information. For this purpose, we chose the family of Biograph PET/CT scanners: the Biograph True-Point (B-TP), Biograph True-Point with TrueV (B-TPTV) and the Biograph mCT. They have similar block detectors and electronics, but a different number of rings and configuration. Some effective parameters of the simulations, such as the dead-time and the size of the reflectors in the detectors, were adjusted to reproduce the sensitivity and noise equivalent count (NEC) rate of the B-TPTV scanner. These parameters were then used to make predictions of experimental results such as sensitivity, NEC rate, spatial resolution, and scatter fraction (SF), from all the Biograph scanners and some variations of them (energy windows and additional rings of detectors). Predictions agree with the measured values for the three scanners, within 7% (sensitivity and NEC rate) and 5% (SF). The resolution obtained for the B-TPTV is slightly better (10%) than the experimental values. In conclusion, we have shown that PeneloPET is suitable for simulating and investigating clinical systems with good accuracy and short computational time, though some effort tuning of a few parameters of the scanners modeled may be needed in case that the full details of the scanners studied are not available.

[18F]FDG PET/CT outperforms [18F]FDG PET/MRI in differentiated thyroid cancer

International Nuclear Information System (INIS)

Vrachimis, Alexis; Wenning, Christian; Weckesser, Matthias; Stegger, Lars; Burg, Matthias Christian; Allkemper, Thomas; Schaefers, Michael

2016-01-01

To evaluate the diagnostic potential of PET/MRI with [ 18 F]FDG in comparison to PET/CT in patients with differentiated thyroid cancer suspected or known to have dedifferentiated. The study included 31 thyroidectomized and remnant-ablated patients who underwent a scheduled [ 18 F]FDG PET/CT scan and were then enrolled for a PET/MRI scan of the neck and thorax. The datasets (PET/CT, PET/MRI) were rated regarding lesion count, conspicuity, diameter and characterization. Standardized uptake values were determined for all [ 18 F]FDG-positive lesions. Histology, cytology, and examinations before and after treatment served as the standards of reference. Of 26 patients with a dedifferentiated tumour burden, 25 were correctly identified by both [ 18 F]FDG PET/CT and PET/MRI. Detection rates by PET/CT and PET/MRI were 97 % (113 of 116 lesions) and 85 % (99 of 113 lesions) for malignant lesions, and 100 % (48 of 48 lesions) and 77 % (37 of 48 lesions) for benign lesions, respectively. Lesion conspicuity was higher on PET/CT for both malignant and benign pulmonary lesions and in the overall rating for malignant lesions (p < 0.001). There was a difference between PET/CT and PET/MRI in overall evaluation of malignant lesions (p < 0.01) and detection of pulmonary metastases (p < 0.001). Surgical evaluation revealed three malignant lesions missed by both modalities. PET/MRI additionally failed to detect 14 pulmonary metastases and 11 benign lesions. In patients with thyroid cancer and suspected or known dedifferentiation, [ 18 F]FDG PET/MRI was inferior to low-dose [ 18 F]FDG PET/CT for the assessment of pulmonary status. However, for the assessment of cervical status, [ 18 F]FDG PET/MRI was equal to contrast-enhanced neck [ 18 F]FDG PET/CT. Therefore, [ 18 F]FDG PET/MRI combined with a low-dose CT scan of the thorax may provide an imaging solution when high-quality imaging is needed and high-energy CT is undesirable or the use of a contrast agent is contraindicated. (orig.)

Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information.

Science.gov (United States)

Holman, Beverley F; Cuplov, Vesna; Millner, Lynn; Endozo, Raymond; Maher, Toby M; Groves, Ashley M; Hutton, Brian F; Thielemans, Kris

2018-06-05

Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and 'snap shot' CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18 F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.

Brain tumors : L-[1-C-11]tyrosine PET for visualization and quantification of protein synthesis rate

NARCIS (Netherlands)

Pruim, J; Willemsen, A T; Molenaar, W M; Waarde, A van; Paans, A M; Heesters, M A; Go, K G; Visser, Gerben; Franssen, E J; Vaalburg, W

1995-01-01

PURPOSE: Positron emission tomography (PET) with the amino acid tracer L-[1-C-11]-tyrosine was evaluated in 27 patients with primary and recurrent brain tumors. MATERIALS AND METHODS: Patients underwent either static (n = 14) or dynamic PET (n = 13), with quantification of protein synthesis rate

Understanding the context for pet cat and dog feeding and exercising behaviour among pet owners in Ireland: a qualitative study

OpenAIRE

Downes, Martin J.; Devitt, Catherine; Downes, Marie T.; More, Simon J.

2017-01-01

Background Pet cat and dog obesity contributes to increased risk of several diseases, including cancer and diabetes mellitus as well as a worsening of orthopaedic problems, and a reduction in survival rate. This study aims to develop a better understanding of cat and dog owners’ self-reported beliefs and factors that influence owner behaviour around feeding and exercising their pet cat or dog, as there is a lack of in-depth understanding in this area. Seven focus group discussions, with 43 pe...

Decay correction methods in dynamic PET studies

International Nuclear Information System (INIS)

Chen, K.; Reiman, E.; Lawson, M.

1995-01-01

In order to reconstruct positron emission tomography (PET) images in quantitative dynamic studies, the data must be corrected for radioactive decay. One of the two commonly used methods ignores physiological processes including blood flow that occur at the same time as radioactive decay; the other makes incorrect use of time-accumulated PET counts. In simulated dynamic PET studies using 11 C-acetate and 18 F-fluorodeoxyglucose (FDG), these methods are shown to result in biased estimates of the time-activity curve (TAC) and model parameters. New methods described in this article provide significantly improved parameter estimates in dynamic PET studies

Comparison between PET/MR and PET/CT in evaluation of oncological patients%PET/MR与PET/CT的对比研究

Institute of Scientific and Technical Information of China (English)

徐白萱; 富丽萍; 关志伟; 尹大一; 刘家金; 杨晖; 张锦明; 陈英茂; 安宁豫

2014-01-01

Objective To verify the feasibility of the integrated PET/MR for oncological applications by comparing PET/MR with PET/CT in terms of lesion detection and quantitative measurement.Methods A total of 277 patients (165 males,112 females,average age (52.9± 12.6) years) voluntarily participated in this same-day PET/CT and PET/MR comparative study.The time interval between the two studies was 15-35 min.PET/CT images were acquired and reconstructed following standard protocols.PET/MR covered the body trunk with a sequence combination of transverse T1 weighted imaging (WI) 3D-volumetric interpolated breath-hold,T2WI turbo spin echo with fat saturation,diffusion-weighted imaging,and simultaneous PET acquisition.PET images were reconstructed by vender-provided attenuation correction methods.The results of PET/CT and PET/MR were regarded as positive if any modality (CT,PET or MRI) was positive.SUVmax was obtained by the manually drawn ROI.Detection rates were compared with x2 test and SUVmax from the two modalities was analyzed with Spearman correlation analysis.Results A total of 353 lesions were detected in 220 patients.Compared to PET/CT,PET/MR revealed 30 additional true-positive lesions,while missed 6.The detection rates between PET/CT and PET/MR were significantly different (P＜0.05).The lesion-based and patient-based consistency was 89.8％ (317/353) and 85.9％ (189/220),respectively.There were significant correlations of SUVmax between PET/MR and PET/CT for lesions(rs =0.91,P＜0.01) and for normal tissues(rs =0.62-0.76,all P＜0.01).Conclusions With reference to PET/CT,integrated PET/MR may provide comparable semi-quantitative measurements of pathological lesions as well as normal tissues.Integrated PET/MR may be more effective to detect lesions in abdomen and pelvis.%目的 通过与PET/CT在病灶检测及定量分析方面的比较,论证PET/MR一体机应用于临床的可行性.方法 2012年5月至2013年2月共300例患者同天间隔15 ～ 35 min行PET/CT和PET

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

Energy Technology Data Exchange (ETDEWEB)

Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh [Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis (United States)

2016-12-15

, the definitive PET/MRI interpretation proved correct. These 12 patients underwent six additional diagnostic studies to clarify the initial indeterminate PET/CT findings. In the remaining 13 of 31 cases with indeterminate findings on both PET/CT and PET/MRI, common reasons for uncertainty included the inability to distinguish reactive from malignant lymphadenopathy (4/13) and local recurrence from treatment effect (2/13). Indeterminate PET/CT findings can result in equivocal reads and additional diagnostic studies. PET/MRI may reduce the rate of indeterminate findings by facilitating better tumor staging, FDG activity localization, and lesion characterization. In our study, PET/MRI resulted in more definitive imaging interpretations with high accuracy. PET/MRI also showed potential in reducing the number of additional diagnostic studies prompted by PET/CT findings. Our results suggest that whole-body PET/MRI provides certain diagnostic advantages over PET/CT, promotes more definitive imaging interpretations, and may improve the overall clinical utility of PET.

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

International Nuclear Information System (INIS)

Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh

2016-01-01

definitive PET/MRI interpretation proved correct. These 12 patients underwent six additional diagnostic studies to clarify the initial indeterminate PET/CT findings. In the remaining 13 of 31 cases with indeterminate findings on both PET/CT and PET/MRI, common reasons for uncertainty included the inability to distinguish reactive from malignant lymphadenopathy (4/13) and local recurrence from treatment effect (2/13). Indeterminate PET/CT findings can result in equivocal reads and additional diagnostic studies. PET/MRI may reduce the rate of indeterminate findings by facilitating better tumor staging, FDG activity localization, and lesion characterization. In our study, PET/MRI resulted in more definitive imaging interpretations with high accuracy. PET/MRI also showed potential in reducing the number of additional diagnostic studies prompted by PET/CT findings. Our results suggest that whole-body PET/MRI provides certain diagnostic advantages over PET/CT, promotes more definitive imaging interpretations, and may improve the overall clinical utility of PET

MRI-assisted PET motion correction for neurologic studies in an integrated MR-PET scanner.

Science.gov (United States)

Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B; Michel, Christian J; El Fakhri, Georges; Schmand, Matthias; Sorensen, A Gregory

2011-01-01

Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MRI data can be used for motion tracking. In this work, a novel algorithm for data processing and rigid-body motion correction (MC) for the MRI-compatible BrainPET prototype scanner is described, and proof-of-principle phantom and human studies are presented. To account for motion, the PET prompt and random coincidences and sensitivity data for postnormalization were processed in the line-of-response (LOR) space according to the MRI-derived motion estimates. The processing time on the standard BrainPET workstation is approximately 16 s for each motion estimate. After rebinning in the sinogram space, the motion corrected data were summed, and the PET volume was reconstructed using the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed, and motion estimates were obtained using 2 high-temporal-resolution MRI-based motion-tracking techniques. After accounting for the misalignment between the 2 scanners, perfectly coregistered MRI and PET volumes were reproducibly obtained. The MRI output gates inserted into the PET list-mode allow the temporal correlation of the 2 datasets within 0.2 ms. The Hoffman phantom volume reconstructed by processing the PET data in the LOR space was similar to the one obtained by processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the procedure. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 s and 20 ms, respectively. Motion-deblurred PET images, with excellent delineation of specific brain structures, were obtained using these 2 MRI

Is the detection rate of 18F-choline PET/CT influenced by androgen-deprivation therapy?

International Nuclear Information System (INIS)

Chondrogiannis, Sotirios; Marzola, Maria Cristina; Grassetto, Gaia; Maffione, Anna Margherita; Rampin, Lucia; Rubello, Domenico; Ferretti, Alice; Fanti, Stefano; Giammarile, Francesco

2014-01-01

To evaluate if the detection rate (DR) of 18 F-choline (18F-CH) PET/CT is influenced by androgen-deprivation therapy (ADT) in patients with prostate cancer (PC) already treated with radical intent and presenting biochemical relapse. We have retrospectively evaluated 18 F-CH PET/CT scans of 325 consecutive PC patients enrolled in the period November 2009 to December 2012 previously treated with radical intent and referred to our centre to perform 18 F-CH PET/CT for biochemical relapse. Two different groups of patients were evaluated. group A included the whole sample of 325 patients (mean age 70 years, range: 49-86) who presented trigger PSA between 0.1 and 80 ng/ml (mean 5.5 ng/ml), and group B included 187 patients (mean age 70 years, range 49-86) with medium-low levels of trigger PSA ranging between 0.5 and 5 ng/ml (mean PSA 2.1 ng/ml); group B was chosen in order to obtain a more homogeneous group of patients in terms of PSA values also excluding both very low and very high PSA levels avoiding the ''a priori'' higher probability of negative or positive PET scan, respectively. At the time of examination, 139 patients from group A and 72 patients from group B were under ADT: these patients were considered to be hormone-resistant PC patients because from their oncologic history (>18 months) an increase of PSA levels emerged despite the ongoing ADT. The relationship between 18 F-CH PET/CT findings and possible clinical predictors was investigated using both univariate and multivariate binary logistic regression analyses, including trigger PSA and ADT. Considering the whole population, overall DR of 18 F-CH PET was 58.2 % (189/325 patients). In the whole sample of patients (group A), both at the univariate and multivariate logistic regression analysis, trigger PSA and ADT were significantly correlated with the DR of 18 F-CH PET (p 18 F-CH PET and ADT. In group B patients only trigger PSA resulted a reliable predictor of the 18 F-CH positivity, since ADT was not

A study on development of fast silicon photomultipliers for TOF-PET Application

International Nuclear Information System (INIS)

Lee, Chae Hun

2011-02-01

micro-pixels with 66 % fill factor. At this condition, the dynamic range was appropriate for measurement of 511 keV gamma photons with LYSO coupling. Additionally integrated quenching capacitors were fabricated with the Metal-Insulator-Metal (MIM) structure which is commonly used in standard CMOS processes. Quenching capacitor C q with 30 fF successfully modified the single photon pulse shape of SiPM. The initial current in the single photon pulse shape was increased, so, the pulse shape became shaper than conventional SiPMs. This sharper pulse shape shortens the rise time of PET detectors coupled to LYSO. 10 to 90 % rise time of the PET detector based on C q integrated SiPM was 22.5 ns while the normal SiPM has 34.3 ns. The performance of fabricated SiPM was experimentally evaluated with parameters such as reverse bias characteristics, single photoelectron spectrum, gain, dark count rate, energy resolution, and Photon Detection efficiency (PDE). The breakdown voltage was around 16.5 V, so the operating voltage was 17 V to 18V. The gain was obtained with the mean spacing method from single photoelectron spectra, and high gain about 2x10 6 was measured. In Na-22 spectrum measurements, the energy resolution was better than 15 % FWHM at 511 keV which is good enough to use in PET. The experimental results show its feasibility to use in TOF-PET application. The fabricated SiPM has better performances than commercial SiPMs except for dark count rates. Due to N+ formation by the direct arsenic implantation, dark count rate was higher than commercials. As a future work, the SiPM fabrication process scheme is needed to study in order to reduce the dark count rate

Assessing the kidney function parameters glomerular filtration rate and effective renal plasma flow with dynamic FDG-PET/MRI in healthy subjects.

Science.gov (United States)

Geist, Barbara K; Baltzer, Pascal; Fueger, Barbara; Hamboeck, Martina; Nakuz, Thomas; Papp, Laszlo; Rasul, Sazan; Sundar, Lalith Kumar Shiyam; Hacker, Marcus; Staudenherz, Anton

2018-05-09

A method was developed to assess the kidney parameters glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) from 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) concentration behavior in kidneys, measured with positron emission tomography (PET) scans. Twenty-four healthy adult subjects prospectively underwent dynamic simultaneous PET/magnetic resonance imaging (MRI) examination. Time activity curves (TACs) were obtained from the dynamic PET series, with the guidance of MR information. Patlak analysis was performed to determine the GFR, and based on integrals, ERPF was calculated. Results were compared to intra-individually obtained reference values determined from venous blood samples. Total kidney GFR and ERPF as estimated by dynamic PET/MRI were highly correlated to their reference values (r = 0.88/p dynamic FDG PET/MRI scans in healthy kidneys. This has advantages for patients getting a routine scan, where additional examinations for kidney function estimation could be avoided. Further studies are required for transferring this PET/MRI method to PET/CT applications.

International validation study for interim PET in ABVD-treated, advanced-stage hodgkin lymphoma

DEFF Research Database (Denmark)

Biggi, Alberto; Gallamini, Andrea; Chauvie, Stephane

2013-01-01

At present, there are no standard criteria that have been validated for interim PET reporting in lymphoma. In 2009, an international workshop attended by hematologists and nuclear medicine experts in Deauville, France, proposed to develop simple and reproducible rules for interim PET reporting...... in lymphoma. Accordingly, an international validation study was undertaken with the primary aim of validating the prognostic role of interim PET using the Deauville 5-point score to evaluate images and with the secondary aim of measuring concordance rates among reviewers using the same 5-point score...

MR-assisted PET Motion Correction for eurological Studies in an Integrated MR-PET Scanner

Science.gov (United States)

Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B.; Michel, Christian J.; El Fakhri, Georges; Schmand, Matthias; Sorensen, A. Gregory

2011-01-01

Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MR data can be used for motion tracking. In this work, a novel data processing and rigid-body motion correction (MC) algorithm for the MR-compatible BrainPET prototype scanner is described and proof-of-principle phantom and human studies are presented. Methods To account for motion, the PET prompts and randoms coincidences as well as the sensitivity data are processed in the line or response (LOR) space according to the MR-derived motion estimates. After sinogram space rebinning, the corrected data are summed and the motion corrected PET volume is reconstructed from these sinograms and the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed and motion estimates were obtained using two high temporal resolution MR-based motion tracking techniques. Results After accounting for the physical mismatch between the two scanners, perfectly co-registered MR and PET volumes are reproducibly obtained. The MR output gates inserted in to the PET list-mode allow the temporal correlation of the two data sets within 0.2 s. The Hoffman phantom volume reconstructed processing the PET data in the LOR space was similar to the one obtained processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the novel MC algorithm. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 seconds and 20 ms, respectively. Substantially improved PET images with excellent delineation of specific brain structures were obtained after applying the MC using these MR-based estimates. Conclusion A novel MR-based MC

Influence of PET/CT-introduction on PET scanning frequency and indications. Results of a multicenter study

International Nuclear Information System (INIS)

Stergar, H.; Bockisch, A.; Eschmann, S.M.; Krause, B.J.; Roedel, R.; Tiling, R.; Weckesser, M.

2007-01-01

Aim: to evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET. Methods: the study included all examinations performed on stand alone PET- or PET/CT-scanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated. Results: the overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities. Conclusions: the introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry. (orig.)

The impact of PET-CT in suspected recurrent ovarian cancer: A prospective multi-centre study as part of the Australian PET Data Collection Project.

Science.gov (United States)

Fulham, M J; Carter, J; Baldey, A; Hicks, R J; Ramshaw, J E; Gibson, M

2009-03-01

To assess the impact of FDG PET-CT on the management of patients with suspected recurrent ovarian cancer and to determine the incremental information provided by PET-CT. This was a prospective, multi-centre, cohort study. Ninety women (mean age 59.9 years; age range 35-85 years) with a previous history of treated epithelial ovarian carcinoma and suspected recurrence based on elevated CA-125, anatomical imaging or clinical symptoms were studied with FDG PET-CT across two States. Referring doctors were asked to specify a management plan pre-PET, if management was altered after PET-CT and, the impact (rated - none, low, medium, high) of PET-CT on patient management. The pre-PET management plan could include radiotherapy, chemotherapy, surgery, and 'other' including observation. Patients were followed at 6 and 12 months and clinical status, evidence of recurrence and progression were recorded. Patients were referred by 34 individual specialists. At least 168 additional sites of disease in 61 patients (68%), not identified by conventional imaging were identified by PET-CT. In 77% the additional lesions were located below the diaphragm and most were nodal or peritoneal. PET-CT affected management in 60% (49% high, 11% medium impact). Patients where more disease was detected with PET-CT were more likely to progress in the following 12 months. For women with previously treated ovarian carcinoma with recurrent disease, PET-CT can: a) alter management in close to 60% of patients, b) detect more sites of disease than abdominal and pelvic CT, c) is superior in the detection of nodal, peritoneal and subcapsular liver disease and d) offers the opportunity for technology replacement in this setting.

MR-assisted PET motion correction in simultaneous PET/MRI studies of dementia subjects.

Science.gov (United States)

Chen, Kevin T; Salcedo, Stephanie; Chonde, Daniel B; Izquierdo-Garcia, David; Levine, Michael A; Price, Julie C; Dickerson, Bradford C; Catana, Ciprian

2018-03-08

Subject motion in positron emission tomography (PET) studies leads to image blurring and artifacts; simultaneously acquired magnetic resonance imaging (MRI) data provides a means for motion correction (MC) in integrated PET/MRI scanners. To assess the effect of realistic head motion and MR-based MC on static [ 18 F]-fluorodeoxyglucose (FDG) PET images in dementia patients. Observational study. Thirty dementia subjects were recruited. 3T hybrid PET/MR scanner where EPI-based and T 1 -weighted sequences were acquired simultaneously with the PET data. Head motion parameters estimated from high temporal resolution MR volumes were used for PET MC. The MR-based MC method was compared to PET frame-based MC methods in which motion parameters were estimated by coregistering 5-minute frames before and after accounting for the attenuation-emission mismatch. The relative changes in standardized uptake value ratios (SUVRs) between the PET volumes processed with the various MC methods, without MC, and the PET volumes with simulated motion were compared in relevant brain regions. The absolute value of the regional SUVR relative change was assessed with pairwise paired t-tests testing at the P = 0.05 level, comparing the values obtained through different MR-based MC processing methods as well as across different motion groups. The intraregion voxelwise variability of regional SUVRs obtained through different MR-based MC processing methods was also assessed with pairwise paired t-tests testing at the P = 0.05 level. MC had a greater impact on PET data quantification in subjects with larger amplitude motion (higher than 18% in the medial orbitofrontal cortex) and greater changes were generally observed for the MR-based MC method compared to the frame-based methods. Furthermore, a mean relative change of ∼4% was observed after MC even at the group level, suggesting the importance of routinely applying this correction. The intraregion voxelwise variability of regional SUVRs

Malignancy rate of biopsied suspicious bone lesions identified on FDG PET/CT

Energy Technology Data Exchange (ETDEWEB)

Adams, Hugo J.A.; Kwee, Thomas C. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands); Klerk, John M.H. de [Meander Medical Center, Department of Nuclear Medicine, Amersfoort (Netherlands); Heggelman, Ben G.F. [Meander Medical Center, Department of Radiology, Amersfoort (Netherlands); Dubois, Stefan V. [Meander Medical Center, Department of Pathology, Amersfoort (Netherlands)

2016-07-15

To determine the malignancy rate of bone lesions identified on FDG PET/CT in patients who have undergone CT-guided biopsy because of the suspicion of malignancy. This single-centre retrospective study spanned eight consecutive years and included all patients who underwent both FDG PET/CT and CT-guided bone biopsy because of the suspicion of malignancy. The positive predictive value (PPV) for malignancy was calculated, and different patient and imaging characteristics were compared between malignant and benign bone lesions. Of 102 included patients with bone lesions that all showed FDG uptake exceeding mediastinal uptake, bone biopsy showed a malignant lesion in 91 patients, yielding a PPV for malignancy of 89.2 % (95 % CI 81.7 - 93.9 %). In the 94 patients with bone lesions that showed FDG uptake exceeding liver uptake, bone biopsy showed a malignant lesion in 83 patients, yielding a PPV for malignancy of 88.3 % (95 % CI 80.1 - 93.5 %). Higher age, bone marrow replacement of the lesion seen on CT, expansion of the lesion seen on CT, and presence of multifocal lesions on FDG PET/CT were significantly more frequent in patients with malignant lesions than in those with benign bone lesions (P = 0.044, P = 0.009, P = 0.015, and P = 0.019, respectively). Furthermore, there was a trend towards a higher incidence of cortical destruction (P = 0.056) and surrounding soft tissue mass (P = 0.063) in patients with malignant bone lesions. The PPV for malignancy of suspicious bone lesions identified on FDG PET/CT is not sufficiently high to justify changes in patient management without histopathological confirmation. Nevertheless, ancillary patient and imaging characteristics may increase the likelihood of a malignant bone lesion. (orig.)

Tumor Delineation and Quantitative Assessment of Glucose Metabolic Rate within Histologic Subtypes of Non-Small Cell Lung Cancer by Using Dynamic 18F Fluorodeoxyglucose PET.

Science.gov (United States)

Meijer, Tineke W H; de Geus-Oei, Lioe-Fee; Visser, Eric P; Oyen, Wim J G; Looijen-Salamon, Monika G; Visvikis, Dimitris; Verhagen, Ad F T M; Bussink, Johan; Vriens, Dennis

2017-05-01

Purpose To assess whether dynamic fluorine 18 ( 18 F) fluorodeoxyglucose (FDG) positron emission tomography (PET) has added value over static 18 F-FDG PET for tumor delineation in non-small cell lung cancer (NSCLC) radiation therapy planning by using pathology volumes as the reference standard and to compare pharmacokinetic rate constants of 18 F-FDG metabolism, including regional variation, between NSCLC histologic subtypes. Materials and Methods The study was approved by the institutional review board. Patients gave written informed consent. In this prospective observational study, 1-hour dynamic 18 F-FDG PET/computed tomographic examinations were performed in 35 patients (36 resectable NSCLCs) between 2009 and 2014. Static and parametric images of glucose metabolic rate were obtained to determine lesion volumes by using three delineation strategies. Pathology volume was calculated from three orthogonal dimensions (n = 32). Whole tumor and regional rate constants and blood volume fraction (V B ) were computed by using compartment modeling. Results Pathology volumes were larger than PET volumes (median difference, 8.7-25.2 cm 3 ; Wilcoxon signed rank test, P PET images is in best agreement with pathology volume and could be useful for NSCLC autocontouring. Differences in glycolytic rate and V B between SCC and AC are relevant for research in targeting agents and radiation therapy dose escalation. © RSNA, 2016 Online supplemental material is available for this article.

Is the detection rate of 18F-choline PET/CT influenced by androgen-deprivation therapy?

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Chondrogiannis, Sotirios; Marzola, Maria Cristina; Grassetto, Gaia; Maffione, Anna Margherita; Rampin, Lucia; Rubello, Domenico [' ' Santa Maria della Misericordia' ' Hospital, Rovigo (Italy). PET/CT Centre; Ferretti, Alice [' ' San Giacomo Apostolo' ' Hospital, Castelfranco Veneto, Treviso (Italy). Service of Medical Physics; Fanti, Stefano [Azienda Ospedaliero-Univ. Policlinico S. Orsola-Malpighi, Bologna (Italy). Dept. of Nuclear Medicine; Giammarile, Francesco [Lyon 1 Univ. Centre Hospitalier Lyon Sud Biophysique, Villeurbanne (Italy). Dept. of Nuclear Medicine

2014-07-15

To evaluate if the detection rate (DR) of {sup 18}F-choline (18F-CH) PET/CT is influenced by androgen-deprivation therapy (ADT) in patients with prostate cancer (PC) already treated with radical intent and presenting biochemical relapse. We have retrospectively evaluated {sup 18}F-CH PET/CT scans of 325 consecutive PC patients enrolled in the period November 2009 to December 2012 previously treated with radical intent and referred to our centre to perform {sup 18}F-CH PET/CT for biochemical relapse. Two different groups of patients were evaluated. group A included the whole sample of 325 patients (mean age 70 years, range: 49-86) who presented trigger PSA between 0.1 and 80 ng/ml (mean 5.5 ng/ml), and group B included 187 patients (mean age 70 years, range 49-86) with medium-low levels of trigger PSA ranging between 0.5 and 5 ng/ml (mean PSA 2.1 ng/ml); group B was chosen in order to obtain a more homogeneous group of patients in terms of PSA values also excluding both very low and very high PSA levels avoiding the ''a priori'' higher probability of negative or positive PET scan, respectively. At the time of examination, 139 patients from group A and 72 patients from group B were under ADT: these patients were considered to be hormone-resistant PC patients because from their oncologic history (>18 months) an increase of PSA levels emerged despite the ongoing ADT. The relationship between {sup 18}F-CH PET/CT findings and possible clinical predictors was investigated using both univariate and multivariate binary logistic regression analyses, including trigger PSA and ADT. Considering the whole population, overall DR of {sup 18}F-CH PET was 58.2 % (189/325 patients). In the whole sample of patients (group A), both at the univariate and multivariate logistic regression analysis, trigger PSA and ADT were significantly correlated with the DR of {sup 18}F-CH PET (p < 0.05). Moreover, the DR in patients under ADT (mean PSA 7.8 ng/ml) was higher than in

Relationship between PSA kinetics and [{sup 18}F]fluorocholine PET/CT detection rates of recurrence in patients with prostate cancer after total prostatectomy

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Graute, Vera; Jansen, Nathalie; Uebleis, Christopher; Cumming, Paul; Klanke, Katharina; Tiling, Reinhold; Bartenstein, Peter; Hacker, Marcus [University of Munich, Department of Nuclear Medicine, Munich (Germany); Seitz, Michael [University of Munich, Department of Urology, Munich (Germany); Hartenbach, Markus [Bundeswehrkrankenhaus Ulm, Department of Nuclear Medicine, Ulm (Germany); Scherr, Michael Karl; Thieme, Sven [University of Munich, Institute of Clinical Radiology, Munich (Germany)

2012-02-15

The aim of the present study was to identify prostate-specific antigen (PSA) threshold levels, as well as PSA velocity, progression rate and doubling time in relation to the detectability and localization of recurrent lesions with [{sup 18}F]fluorocholine (FC) PET/CT in patients after radical prostatectomy. The study group comprised 82 consecutive patients with biochemical relapse after radical prostatectomy. PSA levels measured at the time of imaging were correlated with the FC PET/CT detection rates in the entire group with PSA velocity (in 48 patients), with PSA doubling time (in 47 patients) and with PSA progression (in 29 patients). FC PET/CT detected recurrent lesions in 51 of the 82 patients (62%). The median PSA value was significantly higher in PET-positive than in PET-negative patients (4.3 ng/ml vs. 1.0 ng/ml; p < 0.01). The optimal PSA threshold from ROC analysis for the detection of recurrent prostate cancer lesions was 1.74 ng/ml (AUC 0.818, 82% sensitivity, 74% specificity). Significant differences between PET-positive and PET-negative patients were found for median PSA velocity (6.4 vs. 1.1 ng/ml per year; p < 0.01) and PSA progression (5.0 vs. 0.3 ng/ml per year, p < 0.01) with corresponding optimal thresholds of 1.27 ng/ml per year and 1.28 ng/ml per year, respectively. The PSA doubling time suggested a threshold of 3.2 months, but this just failed to reach statistical significance (p = 0.071). In a study cohort of patients with biochemical recurrence of prostate cancer after radical prostatectomy there emerged clear PSA thresholds for the presence of FC PET/CT-detectable lesions. (orig.)

Early PET imaging with [68]Ga-PSMA-11 increases the detection rate of local recurrence in prostate cancer patients with biochemical recurrence

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Uprimny, Christian; Kroiss, Alexander Stephan; Decristoforo, Clemens; Kendler, Dorota; Guggenberg, Elisabeth von; Nilica, Bernhard; Maffey-Steffan, Johanna; Di Santo, Gianpaolo; Virgolini, Irene Johanna [Medical University Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Fritz, Josef [Medical University Innsbruck, Department of Medical Statistics, Informatics and Health Economics, Innsbruck (Austria); Bektic, Jasmin; Horninger, Wolfgang [Medical University Innsbruck, Department of Urology, Innsbruck (Austria)

2017-09-15

PET/CT using {sup 68}Ga-labelled prostate-specific membrane antigen PSMA-11 (HBEDD-CC) has emerged as a promising imaging method in the diagnostic evaluation of prostate cancer (PC) patients with biochemical recurrence. However, assessment of local recurrence (LR) may be limited by intense physiologic tracer accumulation in the urinary bladder on whole-body scans, normally conducted 60 min post-tracer injection (p.i.). It could be shown on early dynamic imaging studies that {sup 68}Ga-PSMA-11 uptake in PC lesions occurs earlier than tracer accumulation in the urinary bladder. This study aims to investigate whether early static PET acquisition increases detection rate of local recurrence on {sup 68}Ga-PSMA-11 PET/CT in comparison to PET imaging 60 min p.i. 203 consecutive PC patients with biochemical failure referred to {sup 68}Ga-PSMA-11 PET/CT were analysed retrospectively (median prostate specific antigen (PSA) value: 1.44 ng/ml). In addition to whole-body PET/CT scans 60 min p.i., early static imaging of the pelvis was performed, starting at a median time of 283 s p.i. (range: 243-491 s). Assessment was based on visual analysis and calculation of maximum standardized uptake value (SUV{sub max}) of pathologic lesions present in the pelvic area found on early PET imaging and on 60 min-PET scans. 26 patients (12.8%) were judged positive for LR on PET scans 60 min p.i. (median SUV{sub max}: 10.8; range: 4.7-40.9), whereas 50 patients (24.6%) revealed a lesion suggestive of LR on early PET imaging (median SUV{sub max}: 5.9; range: 2.9-17.6), resulting in a significant rise in detection rate (p < 0.001). Equivocal findings on PET scans 60 min p.i. decreased significantly with the help of early imaging (15.8% vs. 4.5% of patients; p < 0.001). Tracer activity in the urinary bladder with a median SUV{sub max} of 8.2 was present in 63 patients on early PET scans (31.0%). However, acquisition starting time of early PET scans differed significantly in the patient groups

Metallic artifacts caused by dental metal prostheses on PET images. A PET/CT phantom study using different PET/CT scanners

International Nuclear Information System (INIS)

Shimamoto, Hiroaki; Kakimoto, Naoya; Murakami, Shumei; Furukawa, Souhei; Fujino, Kouichi; Hamada, Seiki; Shimosegawa, Eku; Hatazawa, Jun

2009-01-01

The objective of this study was to investigate the effects of computed tomography (CT) artifacts caused by dental metal prostheses on positron emission tomography (PET) images. A dental arch cast was fixed in a cylindrical water-bath phantom. A spherical phantom positioned in the vicinity of the dental arch cast was used to simulate a tumor. To simulate the tumor imaging, the ratio of the 18 F-fluoro-deoxy-glucose radioactivity concentration of the spherical phantom to that of the water-bath phantom was set at 2.5. A dental bridge composed of a gold-silver-palladium alloy on the right mandibular side was prepared. A spherical phantom was set in the white artifact area on the CT images (site A), in a slightly remote area from the white artifact (site B), and in a black artifact area (site C). A PET/CT scan was performed with and without the metal bridge at each simulated tumor site, and the artifactual influence was evaluated on the axial attenuation-corrected (AC) PET images, in which the simulated tumor produced the strongest accumulation. Measurements were performed using three types of PET/CT scanners (scanners 1 and 2 with CT-based attenuation correction, and 3 with Cesium-137 ( 137 Cs)-based attenuation correction). The influence of the metal bridge was evaluated using the change rate of the SUVmean with and without the metal bridge. At site A, an overestimation was shown (scanner 1: +5.0% and scanner 2: +2.5%), while scanner 3 showed an underestimation of -31.8%. At site B, an overestimation was shown (scanner 1: +2.1% and scanner 2: +2.0%), while scanner 3 showed an underestimation of -2.6%. However, at site C, an underestimation was shown (scanner 1: -25.0%, scanner 2: -32.4%, and scanner 3: -8.4%). When CT is used for attenuation correction in patients with dental metal prostheses, an underestimation of radioactivity of accumulated tracer is anticipated in the dark streak artifact area on the CT images. In this study, the dark streak artifacts of the CT

[{sup 18}F]FDG PET/CT outperforms [{sup 18}F]FDG PET/MRI in differentiated thyroid cancer

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Vrachimis, Alexis; Wenning, Christian; Weckesser, Matthias; Stegger, Lars [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Burg, Matthias Christian; Allkemper, Thomas [University Hospital Muenster, Department of Clinical Radiology, Muenster (Germany); Schaefers, Michael [University Hospital Muenster, Department of Nuclear Medicine, Muenster (Germany); Westfaelische Wilhelms University Muenster, European Institute for Molecular Imaging, Muenster (Germany)

2016-02-15

To evaluate the diagnostic potential of PET/MRI with [{sup 18}F]FDG in comparison to PET/CT in patients with differentiated thyroid cancer suspected or known to have dedifferentiated. The study included 31 thyroidectomized and remnant-ablated patients who underwent a scheduled [{sup 18}F]FDG PET/CT scan and were then enrolled for a PET/MRI scan of the neck and thorax. The datasets (PET/CT, PET/MRI) were rated regarding lesion count, conspicuity, diameter and characterization. Standardized uptake values were determined for all [{sup 18}F]FDG-positive lesions. Histology, cytology, and examinations before and after treatment served as the standards of reference. Of 26 patients with a dedifferentiated tumour burden, 25 were correctly identified by both [{sup 18}F]FDG PET/CT and PET/MRI. Detection rates by PET/CT and PET/MRI were 97 % (113 of 116 lesions) and 85 % (99 of 113 lesions) for malignant lesions, and 100 % (48 of 48 lesions) and 77 % (37 of 48 lesions) for benign lesions, respectively. Lesion conspicuity was higher on PET/CT for both malignant and benign pulmonary lesions and in the overall rating for malignant lesions (p < 0.001). There was a difference between PET/CT and PET/MRI in overall evaluation of malignant lesions (p < 0.01) and detection of pulmonary metastases (p < 0.001). Surgical evaluation revealed three malignant lesions missed by both modalities. PET/MRI additionally failed to detect 14 pulmonary metastases and 11 benign lesions. In patients with thyroid cancer and suspected or known dedifferentiation, [{sup 18}F]FDG PET/MRI was inferior to low-dose [{sup 18}F]FDG PET/CT for the assessment of pulmonary status. However, for the assessment of cervical status, [{sup 18}F]FDG PET/MRI was equal to contrast-enhanced neck [{sup 18}F]FDG PET/CT. Therefore, [{sup 18}F]FDG PET/MRI combined with a low-dose CT scan of the thorax may provide an imaging solution when high-quality imaging is needed and high-energy CT is undesirable or the use of a contrast

An experimental phantom study of the effect of gadolinium-based MR contrast agents on PET attenuation coefficients and PET quantification in PET-MR imaging: application to cardiac studies.

Science.gov (United States)

O' Doherty, Jim; Schleyer, Paul

2017-12-01

Simultaneous cardiac perfusion studies are an increasing trend in PET-MR imaging. During dynamic PET imaging, the introduction of gadolinium-based MR contrast agents (GBCA) at high concentrations during a dual injection of GBCA and PET radiotracer may cause increased attenuation effects of the PET signal, and thus errors in quantification of PET images. We thus aimed to calculate the change in linear attenuation coefficient (LAC) of a mixture of PET radiotracer and increasing concentrations of GBCA in solution and furthermore, to investigate if this change in LAC produced a measurable effect on the image-based PET activity concentration when attenuation corrected by three different AC strategies. We performed simultaneous PET-MR imaging of a phantom in a static scenario using a fixed activity of 40 MBq [18 F]-NaF, water, and an increasing GBCA concentration from 0 to 66 mM (based on an assumed maximum possible concentration of GBCA in the left ventricle in a clinical study). This simulated a range of clinical concentrations of GBCA. We investigated two methods to calculate the LAC of the solution mixture at 511 keV: (1) a mathematical mixture rule and (2) CT imaging of each concentration step and subsequent conversion to LAC at 511 keV. This comparison showed that the ranges of LAC produced by both methods are equivalent with an increase in LAC of the mixed solution of approximately 2% over the range of 0-66 mM. We then employed three different attenuation correction methods to the PET data: (1) each PET scan at a specific millimolar concentration of GBCA corrected by its corresponding CT scan, (2) each PET scan corrected by a CT scan with no GBCA present (i.e., at 0 mM GBCA), and (3) a manually generated attenuation map, whereby all CT voxels in the phantom at 0 mM were replaced by LAC = 0.1 cm -1 . All attenuation correction methods (1-3) were accurate to the true measured activity concentration within 5%, and there were no trends in image

Reliability of semiquantitative 18F-FDG PET parameters derived from simultaneous brain PET/MRI: A feasibility study

International Nuclear Information System (INIS)

Jena, Amarnath; Taneja, Sangeeta; Goel, Reema; Renjen, Pushpendranath; Negi, Pradeep

2014-01-01

Purpose: Simultaneous brain PET/MRI faces an important issue of validation of accurate MRI based attenuation correction (AC) method for precise quantitation of brain PET data unlike in PET/CT systems where the use of standard, validated CT based AC is routinely available. The aim of this study was to investigate the feasibility of evaluation of semiquantitative 18 F-FDG PET parameters derived from simultaneous brain PET/MRI using ultrashort echo time (UTE) sequences for AC and to assess their agreement with those obtained from PET/CT examination. Methods: Sixteen patients (age range 18–73 years; mean age 49.43 (19.3) years; 13 men 3 women) underwent simultaneous brain PET/MRI followed immediately by PET/CT. Quantitative analysis of brain PET images obtained from both studies was undertaken using Scenium v.1 brain analysis software package. Twenty ROIs for various brain regions were system generated and 6 semiquantitative parameters including maximum standardized uptake value (SUV max), SUV mean, minimum SUV (SUV min), minimum standard deviation (SD min), maximum SD (SD max) and SD from mean were calculated for both sets of PET data for each patient. Intra-class correlation coefficients (ICCs) were determined to assess agreement between the various semiquantitative parameters for the two PET data sets. Results: Intra-class co-relation between the two PET data sets for SUV max, SUV mean and SD max was highly significant (p < 0.00) for all the 20 predefined brain regions with ICC > 0.9. SD from mean was also found to be statistically significant for all the predefined brain regions with ICC > 0.8. However, SUV max and SUV mean values obtained from PET/MRI were significantly lower compared to those of PET/CT for all the predefined brain regions. Conclusion: PET quantitation accuracy using the MRI based UTE sequences for AC in simultaneous brain PET/MRI is reliable in a clinical setting, being similar to that obtained using PET/CT

Pet ownership and risk of asthma: a case-controlled study

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Sharifi

2008-08-01

Full Text Available Background: In the treatment of bronchial asthma, the identification, isolation, and elimination of causative allergens is the most effective part of treatment. With the recent diversification within the pet industry, pet owner exposure to many unknown antigens is on the rise. The results of population studies have been contradictory and some epidemiological studies have failed to confirm this, some indicating that keeping pets might actually reduce the risk of sensitization and asthma. The purpose of this study was to determine the association between pet ownership and asthma. Methods: This case-control study included 300 asthmatic participants referred to the Children's Medical Center over a two-year period. Participants were asked to fill out a questionnaire regarding pet ownership, pet gender and puberty, the place it was kept, how long the pet was kept and the reason for keeping the pet. The same questions were asked from 300 age- and gender-matched nonasthmatic individuals as the control group. Statistical analysis was performed to calculate odds ratios (OR of asthma morbidity in individuals who kept pets. Results: The OR for asthma morbidity in patients who kept pets was 2.59 (CI=1.60-4.21 and p>0.001. Financial aim was the most common reason for keeping a pet and most pets were mature and kept outdoors. No significant correlations for pet genders were observed. Conclusion: This survey provides evidence that pet ownership is an important risk factor for asthma, therefore we suggest that individuals at risk for asthma (atopic individuals must avoid contact with pets. However, more research in this field in Iran is necessary.

Application of PET in breast cancer

International Nuclear Information System (INIS)

Noh, Dong Young

2002-01-01

Positron emission tomography (PET) is an imaging method that employs radionuclide and tomography techniques. Since 1995, we applied PET not only to the diagnosis of breast cancer but also to the detection of abnormalities in the augmented breast and to the detection of metastasis. Until 2001, we evaluated 242 breast cases by PET at PET center of Seoul National University Hospital. Our group has reported serially at the international journals. In the firtst report, PET showed high sensitivity for detecting breast cancer, both the primary and axillary node metastasis. A total of 27 patients underwent breast operations based on PET results at Seoul National University Hospital from 1995 to 1996. The diagnostic accuracy of PET were 97% for the primary tumor mass and 96% for axillary lymph node metastasis. In case of the breast augmented, PET also showed excellent diagnostic results for primary breast cancer and axillary lymph node metastasis where mammography and ultrasound could not diagnose properly. PET also had outstanding results in the detection of recurrent or metastatic breast cancer(sensitivity 94%, specificity 80%, accuracy 89%). In addition, our study gave some evidence that PET could be applied further to evaluate the growth rate of tumors by measuring SUV, and finally to prognosticated the disease. PET could also be applied to evaluate the response after chemotherapy to measure its metabolic rate and size. In conclsion, PET is a highly sensitive, accurate diagnostic tool for breast cancer of primary lesion in various conditions including metastasis

The detection rates and tumor clinical/pathological stages of whole-body FDG-PET cancer screening

International Nuclear Information System (INIS)

Ono, Ken; Omagari, Junichi; Ochiai, Reiji; Yoshida, Tsuyoshi; Kitagawa, Mami; Kobayashi, Hisashi; Yamashita, Yasuyuki

2007-01-01

Fluorodeoxyglucose (FDG)-positron emission tomography (PET) has been used for cancer screening, mainly in East-Asia, and cancers are found not infrequently. However, their stages have not been clarified. We examined the detection rates of various cancers using whole-body PET for the screening of cancers in asymptomatic individuals, focusing on their clinical and pathological stages. Whole-body PET was obtained as a part of our cancer screening program among 3,426 healthy subjects. All subjects participated in a course of PET examination in conjunction with conventional examinations including a medical questionnaire, tumor markers, immunological fecal occult blood test, neck and abdominal ultrasonography and whole body computed tomography. A diagnosis and staging was obtained by an analysis of the pathological findings or by an analysis of the clinical follow-up data. Malignant tumors were discovered in 65 lesions found in 3,426 participants (1.90%). The PET findings were true-positive in 46 of the 65 cancer cases. The cancers were found in the following organs: the colon 14; thyroid gland 10; stomach 7; lung 5; liver 3; breast 2; and one each in the kidney, gallbladder, esophagus, pancreas and retroperitoneum. The stages were as follows: stage 0 5, stage I 17, stage II 10, stage III 7, and stage IV 6. One was an unknown primary. There were 19 false-negative findings (0.6%) on PET. Six cancers (0.18%) were missed in our screening program. PET imaging has the potential to detect a wide variety of cancers at potentially curative stages. Most PET-negative cancers are early stage cancers, and thus can be detected using other conventional examinations such as endoscopy. (author)

Multi institutional quantitative phantom study of yttrium-90 PET in PET/MRI: the MR-QUEST study.

Science.gov (United States)

Maughan, Nichole M; Eldib, Mootaz; Faul, David; Conti, Maurizio; Elschot, Mattijs; Knešaurek, Karin; Leek, Francesca; Townsend, David; DiFilippo, Frank P; Jackson, Kimberly; Nekolla, Stephan G; Lukas, Mathias; Tapner, Michael; Parikh, Parag J; Laforest, Richard

2018-04-04

Yttrium-90 ( 90 Y) radioembolization involves the intra-arterial delivery of radioactive microspheres to treat hepatic malignancies. Though this therapy involves careful pre-treatment planning and imaging, little is known about the precise location of the microspheres once they are administered. Recently, there has been growing interest post-radioembolization imaging using positron-emission tomography (PET) for quantitative dosimetry and identifying lesions that may benefit from additional salvage therapy. In this study, we aim to measure the inter-center variability of 90 Y PET measurements as measured on PET/MRI in preparation for a multi-institutional prospective phase I/II clinical trial. Eight institutions participated in this study and followed a standardized phantom filling and imaging protocol. The NEMA NU2-2012 body phantom was filled with 3 GBq of 90 Y chloride solution. The phantom was imaged for 30 min in listmode on a Siemens Biograph mMR non-TOF PET/MRI scanner at five time points across 10 days (0.3-3.0 GBq). Raw PET data were sent to a central site for image reconstruction and data analysis. Images were reconstructed with optimal parameters determined from a previous study. Volumes of interest (VOIs) matching the known sphere diameters were drawn on the vendor-provided attenuation map and propagated to the PET images. Recovery coefficients (RCs) and coefficient of variation of the RCs (COV) were calculated from these VOIs for each sphere size and activity level. Mean RCs ranged from 14.5 to 75.4%, with the lowest mean RC coming from the smallest sphere (10 mm) on the last day of imaging (0.16 MBq/ml) and the highest mean RC coming from the largest sphere (37 mm) on the first day of imaging (2.16 MBq/ml). The smaller spheres tended to exhibit higher COVs. In contrast, the larger spheres tended to exhibit lower COVs. COVs from the 37 mm sphere were  25%. Post-radioembolization dosimetry of lesions or other VOIs ≥ 22 mm in diameter can

A study of artefacts in simultaneous PET and MR imaging using a prototype MR compatible PET scanner

International Nuclear Information System (INIS)

Slates, R.B.; Farahani, K.; Marsden, P.K.; Taylor, J.; Summers, P.E.; Williams, S.; Beech, J.

1999-01-01

We have assessed the possibility of artefacts that can arise in attempting to perform simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) using a small prototype MR compatible PET scanner (McPET). In these experiments, we examine MR images for any major artefacts or loss in image quality due to inhomogeneities in the magnetic field, radiofrequency interference or susceptibility effects caused by operation of the PET system inside the MR scanner. In addition, possible artefacts in the PET images caused by the static and time-varying magnetic fields or radiofrequency interference from the MR system were investigated. Biological tissue and a T 2 -weighted spin echo sequence were used to examine susceptibility artefacts due to components of the McPET scanner (scintillator, optical fibres) situated in the MR field of view. A range of commonly used MR pulse sequences was studied while acquiring PET data to look for possible artefacts in either the PET or MR images. Other than a small loss in signal-to-noise using gradient echo sequences, there was no significant interaction between the two imaging systems. Simultaneous PET and MR imaging of simple phantoms was also carried out in different MR systems with field strengths ranging from 0.2 to 4.7 T. The results of these studies demonstrate that it is possible to acquire PET and MR images simultaneously, without any significant artefacts or loss in image quality, using our prototype MR compatible PET scanner. (author)

Respiratory gating in cardiac PET

DEFF Research Database (Denmark)

Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

2017-01-01

BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

Simulation study comparing the helmet-chin PET with a cylindrical PET of the same number of detectors

Science.gov (United States)

Ahmed, Abdella M.; Tashima, Hideaki; Yoshida, Eiji; Nishikido, Fumihiko; Yamaya, Taiga

2017-06-01

There is a growing interest in developing brain PET scanners with high sensitivity and high spatial resolution for early diagnosis of neurodegenerative diseases and studies of brain functions. Sensitivity of the PET scanner can be improved by increasing the solid angle. However, conventional PET scanners are designed based on a cylindrical geometry, which may not be the most efficient design for brain imaging in terms of the balance between sensitivity and cost. We proposed a dedicated brain PET scanner based on a hemispheric shape detector and a chin detector (referred to as the helmet-chin PET), which is designed to maximize the solid angle by increasing the number of lines-of-response in the hemisphere. The parallax error, which PET scanners with a large solid angle tend to have, can be suppressed by the use of depth-of-interaction detectors. In this study, we carry out a realistic evaluation of the helmet-chin PET using Monte Carlo simulation based on the 4-layer GSO detector which consists of a 16  ×  16  ×  4 array of crystals with dimensions of 2.8  ×  2.8  ×  7.5 mm3. The purpose of this simulation is to show the gain in imaging performance of the helmet-chin PET compared with the cylindrical PET using the same number of detectors in each configuration. The sensitivity of the helmet-chin PET evaluated with a cylindrical phantom has a significant increase, especially at the top of the (field-of-view) FOV. The peak-NECR of the helmet-chin PET is 1.4 times higher compared to the cylindrical PET. The helmet-chin PET provides relatively low noise images throughout the FOV compared to the cylindrical PET which exhibits enhanced noise at the peripheral regions. The results show the helmet-chin PET can significantly improve the sensitivity and reduce the noise in the reconstructed images.

Clinical utility of flumazenil-PET versus [18F]fluorodeoxyglucose-PET and MRI in refractory partial epilepsy. A prospective study in 100 patients.

Science.gov (United States)

Ryvlin, P; Bouvard, S; Le Bars, D; De Lamérie, G; Grégoire, M C; Kahane, P; Froment, J C; Mauguière, F

1998-11-01

We assessed the clinical utility of [11C]flumazenil-PET (FMZ-PET) prospectively in 100 epileptic patients undergoing a pre-surgical evaluation, and defined the specific contribution of this neuro-imaging technique with respect to those of MRI and [18F]fluorodeoxyglucose-PET (FDG-PET). All patients benefited from a long term video-EEG monitoring, whereas an intracranial EEG investigation was performed in 40 cases. Most of our patients (73%) demonstrated a FMZ-PET abnormality; this hit rate was significantly higher in temporal lobe epilepsy (94%) than in other types of epilepsy (50%) (P lobe epilepsy associated with MRI signs of hippocampal sclerosis, FMZ-PET abnormalities delineated the site of seizure onset precisely, whenever they were coextensive with FDG-PET abnormalities; (ii) in bi-temporal epilepsy, FMZ-PET helped to confirm the bilateral origin of seizures by showing a specific pattern of decreased FMZ binding in both temporal lobes in 33% of cases; (iii) in patients with a unilateral cryptogenic frontal lobe epilepsy, FMZ-PET provided further evidence of the side and site of seizure onset in 55% of cases. Thus, FMZ-PET deserves to be included in the pre-surgical evaluation of these specific categories of epileptic patients, representing approximately half of the population considered for epilepsy surgery.

PET Imaging Stability Measurements During Simultaneous Pulsing of Aggressive MR Sequences on the SIGNA PET/MR System.

Science.gov (United States)

Deller, Timothy W; Khalighi, Mohammad Mehdi; Jansen, Floris P; Glover, Gary H

2018-01-01

The recent introduction of simultaneous whole-body PET/MR scanners has enabled new research taking advantage of the complementary information obtainable with PET and MRI. One such application is kinetic modeling, which requires high levels of PET quantitative stability. To accomplish the required PET stability levels, the PET subsystem must be sufficiently isolated from the effects of MR activity. Performance measurements have previously been published, demonstrating sufficient PET stability in the presence of MR pulsing for typical clinical use; however, PET stability during radiofrequency (RF)-intensive and gradient-intensive sequences has not previously been evaluated for a clinical whole-body scanner. In this work, PET stability of the GE SIGNA PET/MR was examined during simultaneous scanning of aggressive MR pulse sequences. Methods: PET performance tests were acquired with MR idle and during simultaneous MR pulsing. Recent system improvements mitigating RF interference and gain variation were used. A fast recovery fast spin echo MR sequence was selected for high RF power, and an echo planar imaging sequence was selected for its high heat-inducing gradients. Measurements were performed to determine PET stability under varying MR conditions using the following metrics: sensitivity, scatter fraction, contrast recovery, uniformity, count rate performance, and image quantitation. A final PET quantitative stability assessment for simultaneous PET scanning during functional MRI studies was performed with a spiral in-and-out gradient echo sequence. Results: Quantitation stability of a 68 Ge flood phantom was demonstrated within 0.34%. Normalized sensitivity was stable during simultaneous scanning within 0.3%. Scatter fraction measured with a 68 Ge line source in the scatter phantom was stable within the range of 40.4%-40.6%. Contrast recovery and uniformity were comparable for PET images acquired simultaneously with multiple MR conditions. Peak noise equivalent count

Clinical Evaluation of PET Image Quality as a Function of Acquisition Time in a New TOF-PET/MRI Compared to TOF-PET/CT--Initial Results.

Science.gov (United States)

Zeimpekis, Konstantinos G; Barbosa, Felipe; Hüllner, Martin; ter Voert, Edwin; Davison, Helen; Veit-Haibach, Patrick; Delso, Gaspar

2015-10-01

The purpose of this study was to compare only the performance of the PET component between a TOF-PET/CT (henceforth noted as PET/CT) scanner and an integrated TOF-PET/MRI (henceforth noted as PET/MRI) scanner concerning image quality parameters and quantification in terms of standardized uptake value (SUV) as a function of acquisition time (a surrogate of dose). The CT and MR image quality were not assessed, and that is beyond the scope of this study. Five brain and five whole-body patients were included in the study. The PET/CT scan was used as a reference and the PET/MRI acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of the emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts, and noise were evaluated. SUV measurements were taken in the liver and in the white matter to compare quantification. Quantitative evaluation showed strong correlation between PET/CT and PET/MRI brain SUVs. Liver correlation was good, however, with lower uptake estimation in PET/MRI, partially justified by bio-redistribution. The clinical evaluation showed that PET/MRI offers higher image quality and sharpness with lower levels of noise and artifacts compared to PET/CT with reduced acquisition times for whole-body scans while for brain scans there is no significant difference. The TOF-PET/MRI showed higher image quality compared to TOF-PET/CT as tested with reduced imaging times. However, this result accounts mainly for body imaging, while no significant differences were found in brain imaging.

Gender dependent rate of metabolism of the opioid receptor-PET ligand [18F]fluoroethyl-diprenorphine

International Nuclear Information System (INIS)

Henriksen, G.; Spilker, M.E.; Hauser, A.I.; Boecker, H.; Schwaiger, M.; Wester, H.J.; Sprenger, T.; Platzer, S.; Toelle, T.R.

2006-01-01

Aim: The morphinane-derivate 6-O-(2-[ 18 F]fluoroethyl)-6-O-desmethyldiprenorphine ([ 18 F]FDPN) is a non-selective opioid receptor ligand currently used in positron emission tomography (PET). Correction for plasma metabolites of the arterial input function is necessary for quantitative measurements of [ 18 ]FDPN binding. A study was undertaken to investigate if there are gender dependent differences in the rate of metabolism of [ 18 F]FDPN. Methods: The rate of metabolism of [ 18 F]FDPN was mathematically quantified by fitting a bi-exponential function to each individual's dynamic metabolite data. Results: No statistically significant gender differences were found for age, weight, body mass index or dose. However, significant differences (p 18 F]FDPN faster than men. These differences were found in the contribution of the fast and slow kinetic components of the model describing the distribution of radioactive species in plasma, indicating a higher rate of enzyme-dependent degradation of [ 18 F]FDPN in women than in men. Conclusion: The findings reinforce the need for individualized metabolite correction during [ 18 F]FDPN-PET scans and also indicate that in certain cases, grouping according to gender could be performed in order to minimize methodological errors of the input function prior to kinetic analyses. (orig.)

PET studies in dementia

International Nuclear Information System (INIS)

Herholz, K.

2003-01-01

Measurement of local cerebral glucose metabolism (lCMRGlc) by positron emission tomography (PET) and 18 F-2-fluoro-2-deoxy-D-glucose (FDG) has become a standard technique during the past 20 years and is now available at many university hospitals in all highly developed countries. Many studies have documented a close relation between lCMRGlc and localized cognitive functions, such as language and visuoconstructive abilities. Alzheimer's disease (AD) is characterized by regional impairment of cerebral glucose metabolism in neocortical association areas (posterior cingulate, temporoparietal and frontal multimodal association cortex), whereas primary visual and sensorimotor cortex, basal ganglia, and cerebellum are relatively well preserved. In a multicenter study comprising 10 PET centers (Network for Efficiency and Standardization of Dementia Diagnosis, NEST-DD) that employed an automated voxel-based analysis of FDG PET images, the distinction between controls and AD patients was 93% sensitive and 93% specific, and even in very mild dementia (at Mini Mental Status Examination (MMSE) 24 or higher) sensitivity was still 84% at 93% specificity. Significantly abnormal metabolism in mild cognitive deficit (MCI) indicates a high risk to develop dementia within the next two years. Reduced neocortical glucose metabolism can probably be detected with FDG PET in AD on average one year before onset of subjective cognitive impairment. In addition to glucose metabolism, specific tracers for dopamine synthesis ( 18 F-F-DOPA) and for ( 11 C-MP4A) are of interest for differentiation among dementia subtypes. Cortical acetylcholine esterase activity (AChE) activity is significantly lower in patients with AD or with dementia with Lewy bodies (DLB) than in age-matched normal controls. In LBD there is also impairment of dopamine synthesis, similar to Parkinson disease. (author) 115 refs

PET studies in dementia

Energy Technology Data Exchange (ETDEWEB)

Herholz, K. [Neurologische Universitaetsklinik and Max-Planck-Inst. fuer neurologische Forschung, Koeln (Germany)

2003-04-01

Measurement of local cerebral glucose metabolism (lCMRGlc) by positron emission tomography (PET) and {sup 18}F-2-fluoro-2-deoxy-D-glucose (FDG) has become a standard technique during the past 20 years and is now available at many university hospitals in all highly developed countries. Many studies have documented a close relation between lCMRGlc and localized cognitive functions, such as language and visuoconstructive abilities. Alzheimer's disease (AD) is characterized by regional impairment of cerebral glucose metabolism in neocortical association areas (posterior cingulate, temporoparietal and frontal multimodal association cortex), whereas primary visual and sensorimotor cortex, basal ganglia, and cerebellum are relatively well preserved. In a multicenter study comprising 10 PET centers (Network for Efficiency and Standardization of Dementia Diagnosis, NEST-DD) that employed an automated voxel-based analysis of FDG PET images, the distinction between controls and AD patients was 93% sensitive and 93% specific, and even in very mild dementia (at Mini Mental Status Examination (MMSE) 24 or higher) sensitivity was still 84% at 93% specificity. Significantly abnormal metabolism in mild cognitive deficit (MCI) indicates a high risk to develop dementia within the next two years. Reduced neocortical glucose metabolism can probably be detected with FDG PET in AD on average one year before onset of subjective cognitive impairment. In addition to glucose metabolism, specific tracers for dopamine synthesis ({sup 18}F-F-DOPA) and for ({sup 11}C-MP4A) are of interest for differentiation among dementia subtypes. Cortical acetylcholine esterase activity (AChE) activity is significantly lower in patients with AD or with dementia with Lewy bodies (DLB) than in age-matched normal controls. In LBD there is also impairment of dopamine synthesis, similar to Parkinson disease. (author) 115 refs.

64Cu-PSMA-617 PET/CT Imaging of Prostate Adenocarcinoma: First In-Human Studies.

Science.gov (United States)

Grubmüller, Bernhard; Baum, Richard P; Capasso, Enza; Singh, Aviral; Ahmadi, Yasaman; Knoll, Peter; Floth, Andreas; Righi, Sergio; Zandieh, Shahin; Meleddu, Carlo; Shariat, Shahrokh F; Klingler, Hans Christoph; Mirzaei, Siroos

2016-10-07

The prostate-specific membrane antigen (PSMA) is a cell surface protein, which is overexpressed in nearly all cases of prostate cancer (PCa). PET imaging with 68 Ga-PSMA-HBED-CC has recently found widespread application in the diagnosis of recurrent PCa. In this study, the diagnostic potential of 64 Cu-labeled PSMA ligand (PSMA-617) PET in patients with PCa has been investigated. The study was conducted simultaneously at two nuclear medicine centers, Austria (Vienna, Center 1) and Germany (Bad Berka, Center 2). The patients (n = 29) included in this study were referred for PET (Center 1, 21 patients) or PET/CT (Center 2, 8 patients) imaging with either a high suspicion of recurrent disease or for possible surgical or PSMA radioligand therapy planning. PET images of the whole body were performed at 1 hour p.i. and additional images of the pelvis at 2 hours p.i. In 23 of 29 patients, at least one focus of pathological tracer uptake suspicious for primary disease in the prostate lobe or recurrent disease was detected. Among healthy organs, the salivary glands, kidneys, and liver showed the highest radiotracer uptake. Lesions suspicious for PCa were detected with excellent contrast as early as 1 hour p.i. with high detection rates even at low prostate-specific antigen (PSA) levels. The preliminary results of this study demonstrate the high potential of 64 Cu-PSMA ligand PET/CT imaging in patients with recurrent disease and in the primary staging of selected patients with progressive local disease. The acquired PET images showed an excellent resolution of the detected lesions with very high lesion-to- background contrast. Furthermore, the long half-life of 64 Cu allows distribution of the tracer to clinical PET centers that lack radiochemistry facilities for the preparation of 68 Ga-PSMA ligand (satellite concept).

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

International Nuclear Information System (INIS)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick

2015-01-01

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

Energy Technology Data Exchange (ETDEWEB)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick [Nuclear Medicine, University Hospital Zurich (Switzerland)

2015-05-18

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

PET-Studies in parkinson's disease

International Nuclear Information System (INIS)

Schwarz, J.

2002-01-01

Positron-emission-tomography (PET) has enabled to study the metabolism and blood flow in specific brain areas. Besides, there is a variety of radiotracers that allow quantification of the function of distinct molecules. In respect to Parkinson's disease, PET allowed for the first time to assess the number of dopaminergic neurons in vivo. Thus, helping confirming a dopaminergic deficit, measuring disease progression and also help to determine the function of dopaminergic grafts. Current research has shifted to determine the role of related neurotransmitter systems in the pathophysiology of Parkinson's disease. (orig.) [de

Activity of the basal ganglia in Parkinson's disease estimated by PET

International Nuclear Information System (INIS)

Ohye, Chihiro

1995-01-01

Positron emission tomographic (PET) studies on the local cerebral blood flow, oxygen metabolic rate, glucose metabolic rate in the basal ganglia of Parkinson's disease are reviewed. PET has demonstrated that blood flow was decreased in the cerebral cortex, especially the frontal region, of Parkinson's disease and that specific change in blood flow or metabolic rate in the basal ganglia was detected only in patients with hemi-parkinsonism. In authors' study on PET using 18 FDG in patients with tremor type and rigid type Parkinson's disease, changes in blood flow and metabolic rate were minimal at the basal ganglia level in tremor type patients, but cortical blood flow was decreased and metabolic rate was more elevated in the basal ganglia in rigid type patients. These findings were correlated with depth micro-recordings obtained by stereotactic pallidotomy. PET studies have also revealed that activity in the nerve terminal was decreased with decreasing dopamine and that dopamine (mainly D 2 ) activity was remarkably increased. PET studies with specific tracers are promising in providing more accurate information about functional state of living human brain with minimal invasion to patients. (N.K.)

MRI compatibility study of an integrated PET/RF-coil prototype system at 3 T

Science.gov (United States)

Akram, Md Shahadat Hossain; Obata, Takayuki; Suga, Mikio; Nishikido, Fumihiko; Yoshida, Eiji; Saito, Kazuyuki; Yamaya, Taiga

2017-10-01

We have been working on the development of a PET insert for existing magnetic resonance imaging (MRI) systems for simultaneous PET/MR imaging, which integrates radiofrequency (RF)-shielded PET detector modules with an RF head coil. In order to avoid interferences between the PET detector circuits and the different MRI-generated electromagnetic fields, PET detector circuits were installed inside eight Cu-shielded fiber-reinforced plastic boxes, and these eight shielded PET modules were integrated in between the eight elements of a 270-mm-diameter and 280-mm-axial-length cylindrical birdcage RF coil, which was designed to be used with a 3-T clinical MRI system. The diameter of the PET scintillators with a 12-mm axial field-of-view became 255 mm, which was very close to the imaging region. In this study, we have investigated the effects of this PET/RF-coil integrated system on the performance of MRI, which include the evaluation of static field (Bo) inhomogeneity, RF field (B1) distribution, local specific absorption rate (SAR) distribution, average SAR, and signal-to-noise ratio (SNR). For the central 170-mm-diameter and 80-mm-axial-length of a homogenous cylindrical phantom (with the total diameter of 200 mm and axial-length of 100 mm), an increase of about a maximum of 3 μT in the Bo inhomogeneity was found, both in the central and 40-mm off-centered transverse planes, and a 5 percentage point increase of B1 field inhomogeneity was observed in the central transverse plane (from 84% without PET to 79% with PET), while B1 homogeneity along the coronal plane was almost unchanged (77%) following the integration of PET with the RF head coil. The average SAR and maximum local SAR were increased by 1.21 and 1.62 times, respectively. However, the SNR study for both spin-echo and gradient-echo sequences showed a reduction of about 70% and 60%, respectively, because of the shielded PET modules. The overall results prove the feasibility of this integrated PET/RF-coil system

A comparative study of FDG PET/CT and enhanced multi-detector CT for detecting liver metastasis according to the size and location.

Science.gov (United States)

Park, Jung Mi; Kim, Il Young; Kim, Sang Won; Lee, Sang Mi; Kim, Hyun Gi; Kim, Shin Young; Shin, Hyung Chul

2013-04-01

The aim of this study was to compare the diagnosability between (18)F-fluorodeoxyglucose (FDG) PET/CT and enhanced multi-detector CT (MDCT) for the detection of liver metastasis (LM) according to the size and location in liver and to evaluate standard maximum standardized uptake values (SUVmax) of all liver metastatic lesions. One hundred two consecutive patients with malignancy who underwent both FDG PET/CT and MDCT for LM evaluation were retrospectively reviewed. Among them, 56 patients with LM were enrolled in this study. LM was confirmed by follow-up imaging studies after at least 6 months or by histopathology. FDG PET/CT and MDCT images were visually analyzed using three-point scale by the consensus of two radiologists and two nuclear medicine physicians. The size and location (central vs. sub-capsular) of the all liver lesions were evaluated using MDCT images. Furthermore, SUVmax of all liver lesions on FDG PET/CT images were calculated. A total of 146 liver lesions were detected by FDG PET/CT and MDCT and 142 of the lesions were diagnosed as LM. The detection rates of MDCT and FDG PET/CT for LM by visual analysis were 77 and 78%, respectively. There was no significant difference of detection rate according to the overall location and size of the lesions. However, FDG PET/CT was more sensitive than MDCT for detecting small and sub-capsular LM. The detection rate of FDG PET/CT for LM was 68% by the cutoff SUVmax of 2.7. Although the diagnosabilities of MDCT and FDG PET/CT for detecting LM were comparable, FDG PET/CT is superior to MDCT for detecting small LM located in the sub-capsular portion of liver.

Relationship between sources of pet acquisition and euthanasia of cats and dogs in an animal shelter: a pilot study.

Science.gov (United States)

Arbe Montoya, A I; Rand, J S; Greer, R M; Alberthsen, C; Vankan, D

2017-06-01

Approximately 140,000 unwanted dogs and cats are culled in Australia annually. There is a paucity of information linking sources of pet acquisition with subsequent euthanasia, which may inform evidence-based strategies to reduce euthanasia rates. This pilot study aimed to determine whether there is a higher risk of euthanasia related to the source of acquisition for pets surrendered to an animal shelter. Data for 5391 dogs and 5581 cats surrendered to one Queensland shelter between January 2006 and December 2009 were analysed. The main sources of acquisition for owner-surrendered dogs were 'shelter' and 'pet shop' and for owner-surrendered cats were 'own litter' and 'shelter'. Euthanasia rates for different sources varied. For adult dogs, acquisition through newspaper advertisements was associated with the highest euthanasia rate. Adult cats obtained as gifts (from friend or family member) had the highest euthanasia rate. For junior cats, the overwhelming source was the owner's own litter (68% of intake) and only kittens acquired as strays were at significantly higher risk of euthanasia. For both dogs and cats, animals acquired from shelters had lower rates of euthanasia than most other sources, which suggests that shelter-sourced animals may be considered a preferred source for pet acquisition to assist in reducing the number of adoptable pets euthanased. There was evidence from the study animal shelter that the risk of euthanasia was related to acquisition source. These findings should be confirmed by prospective studies, which should also investigate the interaction between acquisition source and other factors, using larger data sets from a variety of shelters. © 2017 Australian Veterinary Association.

Comparison of the performance of {sup 18}F-FP-CIT brain PET/MR and simultaneous PET/CT: A preliminary study

Energy Technology Data Exchange (ETDEWEB)

Kwon, Sang Don; Chun, Kyung Ah [Dept. of Nuclear Medicine, Yeungnam University Hospital, Daegu (Korea, Republic of)

2016-09-15

{sup 18}F-FP-CIT [{sup 1'}8F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional {sup 18}F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.{sup 18}F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of {sup 18}F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BRright caudate - ICC, 0.944; 95 % CI, 0.835-0.981, BRleft caudate - ICC, 0.917; 95 % CI, 0.753-0.972, BRright putamen - ICC, 0.976; 95 % CI, 0.929-0.992 and BRleft putamen - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of

Cancer screening with FDG-PET

International Nuclear Information System (INIS)

Ide, M.

2006-01-01

Aim: This study is based on medical health check-up and cancer screening on of a medical health club using PET, MRI, spiral CT and other conventional examinations. Methods: Between October 1994 and June 2005, 9357 asymptomatic members of the health club participated in 24772 screening session (5693 men and 3664 women, mean age 52.2±10.4 years). Results: Malignant tumors were discovered in 296 of the 9357 participants (3.16%) and 24772 screening sessions (1.19%). The detection rate of our program is much higher than that of mass screening in Japan. The thyroid, lung, colon and breast cancers were PET positive, but the prostate, renal and bladder cancers were generally PET negative. Conclusion: FDG-PET has the potential to detect a wide variety of cancers at curable stages in asymptomatic individuals. To reduce false-positive and false-negative results of PET examination, there is a need of experienced radiologist and/or oncologists who had training in the wide aspect of FDG-PET. FDG-PET has limitations in the detection of urological cancers, cancers of low cell density, small cancers and hypo metabolic or FDG non-avid cancers. Therefore, conventional examinations and/or PET/CT are also needed for cancer screening in association with FDG-PET

Imaging and PET - PET/CT imaging

International Nuclear Information System (INIS)

Von Schulthess, G.K.; Hany, Th.F.

2008-01-01

PET/CT has grown because the lack of anatomic landmarks in PET makes 'hardware-fusion' to anatomic cross-sectional data extremely useful. Addition of CT to PET improves specificity, but also sensitivity, and adding PET to CT adds sensitivity and specificity in tumor imaging. The synergistic advantage of adding CT is that the attenuation correction needed for PET data can also be derived from the CT data. This makes PET-CT 25-30% faster than PET alone, leading to higher patient throughput and a more comfortable examination for patients typically lasting 20 minutes or less. FDG-PET-CT appears to provide relevant information in the staging and therapy monitoring of many tumors, such as lung carcinoma, colorectal cancer, lymphoma, gynaecological cancers, melanoma and many others, with the notable exception of prostatic cancer. for this cancer, choline derivatives may possibly become useful radiopharmaceuticals. The published literature on the applications of FDG-PET-CT in oncology is still limited but several designed studies have demonstrated the benefits of PET-CT. (authors)

(18)F-FDG dynamic PET/CT in patients with multiple myeloma: patterns of tracer uptake and correlation with bone marrow plasma cell infiltration rate.

Science.gov (United States)

Sachpekidis, Christos; Mai, Elias K; Goldschmidt, Hartmut; Hillengass, Jens; Hose, Dirk; Pan, Leyun; Haberkorn, Uwe; Dimitrakopoulou-Strauss, Antonia

2015-06-01

The value of F-FDG PET in the diagnostic approach of multiple myeloma (MM) remains incompletely elicited. Little is known about the kinetics of F-FDG in the bone marrow and extramedullary sites in MM. This study aimed to evaluate quantitative data on kinetics and distribution patterns of F-FDG in MM patients with regard to pelvic bone marrow plasma cell infiltration. The study included 40 patients with primary MM. Dynamic PET/CT scanning of the lower lumbar spine and pelvis was performed after the administration of F-FDG. Whole-body PET/CT studies were performed. Sites of focal increased tracer uptake were considered as highly suggestive of myelomatous involvement after taking into account the patient history and CT findings. Bone marrow of the os ilium without pathologic tracer accumulation served as reference. The evaluation of dynamic PET/CT studies was based in addition to the conventional visual (qualitative) assessment, on semiquantitative (SUV) calculations, as well as on absolute quantitative estimations after application of a 2-tissue compartment model and a noncompartmental approach. F-FDG quantitative information and corresponding distribution patterns were correlated with pelvic bone marrow plasma cell infiltration. Fifty-two myelomatous lesions were detected in the pelvis. All parameters in suspected MM lesions ranged in significantly higher levels than in reference tissue (P PET/CT imaging demonstrated 4 patterns of tracer uptake; these are as follows: negative, focal, diffuse, and mixed (focal/diffuse) tracer uptake. Patients with a mixed pattern of radiotracer uptake had the highest mean plasma cell infiltration rate in their bone marrow, whereas those with negative PET/CT scans demonstrated the lowest bone marrow plasma cell infiltration. In total, 265 focal myeloma-indicative F-FDG-avid lesions were detected, 129 of which correlated with low-dose CT osteolytic findings. No significant correlation between the number of focal lesions detected in PET

Driving with Pets as a Risk Factor for Motor Vehicle Collisions among Older Drivers

Science.gov (United States)

Blunck, Hallie; Owsley, Cynthia; MacLennan, Paul A.; McGwin, Gerald

2015-01-01

Increasing rates of distraction-related motor vehicle collisions (MVCs) continue to raise concerns regarding driving safety. This study sought to evaluate a novel driving-related distraction, driving with a pet, as a risk factor for MVCs among older, community dwelling adults. Two thousand licensed drivers aged 70 and older were identified, of whom 691 reported pet ownership. Comparing pet owners who did and did not drive with their pets, neither overall MVC rates (rate ratio [RR] 0.97 95% confidence interval [CI] 0.75–1.26) nor at-fault MVC rates (RR 0.84 95% CI 0.57–1.24) were elevated. However, those who reported always driving with a pet in the vehicle had an elevated MVC rate (RR 1.89 95% CI 1.10–3.25), as compared to those who did not drive with a pet. The MVC rate was not increased for those reporting only sometimes or rarely driving with a pet in the vehicle. The current study demonstrates an increased risk of MVC involvement in those older drivers who always take a pet with them when they drive a vehicle. When confronted with an increased cognitive or physical workload while driving, elderly drivers in prior studies have exhibited slower cognitive performance and delayed response times in comparison to younger age groups. Further study of pet-related distracted driving behaviors among older drivers as well as younger populations with respect to driver safety and performance is warranted to appropriately inform the need for policy regulation on this issue. PMID:23708755

The clinical impact of [18F]-FDG Pet during the opening year of a Pet centre

Directory of Open Access Journals (Sweden)

Talbot Jean-Noël

2002-01-01

Full Text Available We have evaluated the clinical impact of FDG-PET on patient staging and management during the opening year of our PET centre in France. A questionnaire, translation in French of the questionnaire used recently in California, was sent to the referring physician of each of the 476 patients who had at least one routine FDG-PET examination during the year 2000. Of 348 responses (response rate = 73%, the disease was upstaged in 26% of the cases and downstaged in 9%. Inter-modality management changes (change from a scheduled therapeutic modality for a different one were reported in 37% of the cases and intra-modality changes in 9%. Those modification rates were respectively 38% and 7% in recurrence of colorectal cancer (153 patients, 47% and 7% in lung cancer (118 patients, 16% and 23% in lymphoma (43 patients, 25% and 6% in the staging of head and neck cancers (32 patients.When comparing with the similar studies performed in California, there were no significant differences between the rates of inter-modality management changes. In contrast, intra-modality management changes were less frequent in our survey, except for lymphoma. Globally, the clinical impact of FDG PET was similar, with a higher response rate to our survey (73% versus 35%; it was above the mean 31% rate of therapeutic modification derived from a recent tabulated summary in over 3400 patients.

Serotonin synthesis studied with positron emission tomography, (PET)

DEFF Research Database (Denmark)

Honoré, Per Gustaf Hartvig; Lundquist, Pinelopi

Positron emission tomography (PET) has the potential to study the biosynthesis and release of serotonin (5HT) at brain serotonergic neurons. PET requires probe compounds with specific attributes to enable imaging and quantification of biological processes. This section focuses on probes to measure...

Choline-PET/CT for imaging prostate cancer; Cholin-PET/CT zur Bildgebung des Prostatakarzinoms

Energy Technology Data Exchange (ETDEWEB)

Krause, Bernd Joachim [Klinik- und Poliklinik fuer Nuklearmedizin, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany); Treiber, U.; Schwarzenboeck, S.; Souvatzoglou, M. [Klinik fuer Urologie, Klinikum rechts der Isar, Technische Univ. Muenchen (Germany)

2010-09-15

PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives are increasingly being used for imaging of prostate cancer. The value of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in biochemical recurrence of prostate cancer has been examined in many studies and demonstrates an increasing importance. Primary prostate cancer can be detected with moderate sensitivity using PET and PET/CT using [{sup 11}C]- and [{sup 18}F]-labelled choline derivatives - the differentiation between benign prostatic hyperplasia, prostatitis or high-grade intraepithelial neoplasia (HGPIN) is not always possible. At the present time [{sup 11}C]choline PET/CT is not recommended in the primary setting but may be utilized in clinically suspected prostate cancer with repeatedly negative prostate biopsies, in preparation of a focused re-biopsy. Promising results have been obtained for the use of PET and PET/CT with [{sup 11}C]- and [{sup 18}F]-labelled choline derivates in patients with biochemical recurrence. The detection rate of choline PET and PET/CT for local, regional, and distant recurrence in patients with a biochemical recurrence shows a linear correlation with PSA values at the time of imaging and reaches about 75% in patients with PSA > 3 ng/mL. At PSA values below 1 ng/mL, the recurrence can be diagnosed with choline PET/CT in approximately 1/3 of the patients. PET and PET/CT with [{sup 11}C]- and [{sup 18}F]choline derivates can be helpful for choosing a therapeutic strategy in the sense of an individualized treatment: since an early diagnosis of recurrence is crucial to the choice of optimal treatment. The localization of the site of recurrence - local recurrence, lymph node metastasis or systemic dissemination - has important influence on the therapy regimen. (orig.)

Simultaneous hyperpolarized 13C-pyruvate MRI and 18F-FDG-PET in cancer (hyperPET)

DEFF Research Database (Denmark)

Gutte, Henrik; Hansen, Adam E.; Henriksen, Sarah T.

2015-01-01

named this concept hyper PET. Intravenous injection of the hyperpolarized 13C-pyruvate results in an increase of 13C-lactate, 13C-alanine and 13CCO2 (13C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization (DNP) and use......In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized 13C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and 18F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We have...... of 13C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of 13C-pyruvate to 13C-lactate. In this study, we combined it with 18F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified local recurrence...

Receptor study of psychiatric disorders using PET

International Nuclear Information System (INIS)

Suhara, Tetsuya

1992-01-01

Recent receptor studies of psychiatric disorders using PET have been focused on the change in the number of D 2 dopamine receptors in the striatum of drug-naive schizophrenic patients. One study confirmed an increase in D 2 receptors, while another study denied it. Although there were some differences in the approaches of the two groups, the reason for the discrepancy is not clear yet. Looking to psychiatric disorders other than schizophrenia, our recent study revealed a possible role of dopamine D 1 receptors in bipolar mood disorders. However, some problems must be resolved for further receptor studies with PET. For example, our recent study shows that desipamine decreases the in vivo binding of dopramine D 1 and D 2 receptors whereas these is no effect on dopamine D 1 and D 2 receptors in vitro. Additionally significant methodological problems lie in the method of evaluation of the non-specific binding and the effect of endogenous neurotransmitters. Moreover, difficulties in the diagnosis of psychiatric disorders and ethical problems in psychiatric research are critical factors in receptor studies with PET in psychiatric disorders. (author)

Investigating the impact of LSO on the count rate of wholebody PET tomographs

International Nuclear Information System (INIS)

Douglas, J.L.; Moisan, C.; Rogers, J.G.

1996-05-01

We investigated the impact of using detectors made of lutetium oxyorthosilicate (LSO) on the count rate performances of wholebody PET tomographs. To that end, we used a single computational model that predicts the prompt and random contributions to the total event rate in septaless PET tomographs. Dead time factors at all stages of a typical event acquisition stream are calculated from specified values of their respective processing clock cycle. We validated our approach by fitting the true, random and multiple count rates measured with the ECAT-953B and the EXACT HR PLUS scanners for a standard 20 x 20 cm cylindrical phantom. We then investigated the implications of using position encoding detectors made of LSO in the EXACT HR PLUS scanner geometry. The results in indicate that only replacing BGO by the faster LSO incurs no appreciable change in the maximum noise-equivalent-count (NEC) rate of the scanner. However, one could realistically increase the NEC by a factor 2.5 using a 4 nsec coincidence window width with the detector processing front-end operating on a 128 nsec clock cycle. Further reducing the coincidence window width to 600 psec and the front-end clock cycle to 64 nsec leads to an increase of the NEC by a factor 7.5. To sustain the operation of an HR Plus with these specifications, the saturation bandwidth of the data acquisition system would have to be increased to no more than 4.5 MHz. (authors)

Who wants cancer screening with PET?

International Nuclear Information System (INIS)

Yasunaga, Hideo

2009-01-01

Objectives: Cancer screening using whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) has gradually become popular in Japan. Although some studies have reported high cancer detection rates with PET screening, the justification for such an approach is still unclear, and no evidence has been provided to indicate that PET screening reduces cancer mortality. We measured the general public's willingness to pay (WTP) for this service using a contingent valuation method, after providing them with sufficient information regarding the efficacy and limitations of the service. Methods: A computer-assisted questionnaire survey was conducted on males and females in Japan aged between 40 and 59 years. The study participants (n = 390) were provided with sufficient information about the PET procedure, the high cancer detection rate, false-negatives/false-positives and the fact that the mortality-reducing effect of PET screening has not yet been demonstrated. The participants' WTP was ascertained by a double-bound dichotomous choice approach. Results: The average WTP among all the participants was $68.0 (95% confidence interval: $56.9-79.2). A Weibull regression analysis showed that income, degree of concern about health, and family history of cancer were significant factors affecting WTP. Conclusions: The actual charge for PET screening in Japan is approximately $1000 on average, which is significantly higher than the participants' WTP for the actual benefit obtained from the service. If the Japanese healthcare consumers are well-informed, most of them would avoid purchasing such a costly service.

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Mustafa Demir; Türkay Toklu; Mohammad Abuqbeitah; Hüseyin Çetin; H. Sezer Sezgin; Nami Yeyin; Kerim Sönmezoğlu

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated...

Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests

OpenAIRE

Demir, Mustafa; Toklu, Türkay; Abuqbeitah, Mohammad; Çetin, Hüseyin; Sezgin, H. Sezer; Yeyin, Nami; Sönmezoğlu, Kerim

2018-01-01

Objective: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. Methods: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated asp...

Towards Implementing an MR-based PET Attenuation Correction Method for Neurological Studies on the MR-PET Brain Prototype

Science.gov (United States)

Catana, Ciprian; van der Kouwe, Andre; Benner, Thomas; Michel, Christian J.; Hamm, Michael; Fenchel, Matthias; Fischl, Bruce; Rosen, Bruce; Schmand, Matthias; Sorensen, A. Gregory

2013-01-01

A number of factors have to be considered for implementing an accurate attenuation correction (AC) in a combined MR-PET scanner. In this work, some of these challenges were investigated and an AC method based entirely on the MR data obtained with a single dedicated sequence was developed and used for neurological studies performed with the MR-PET human brain scanner prototype. Methods The focus was on the bone/air segmentation problem, the bone linear attenuation coefficient selection and the RF coil positioning. The impact of these factors on the PET data quantification was studied in simulations and experimental measurements performed on the combined MR-PET scanner. A novel dual-echo ultra-short echo time (DUTE) MR sequence was proposed for head imaging. Simultaneous MR-PET data were acquired and the PET images reconstructed using the proposed MR-DUTE-based AC method were compared with the PET images reconstructed using a CT-based AC. Results Our data suggest that incorrectly accounting for the bone tissue attenuation can lead to large underestimations (>20%) of the radiotracer concentration in the cortex. Assigning a linear attenuation coefficient of 0.143 or 0.151 cm−1 to bone tissue appears to give the best trade-off between bias and variability in the resulting images. Not identifying the internal air cavities introduces large overestimations (>20%) in adjacent structures. Based on these results, the segmented CT AC method was established as the “silver standard” for the segmented MR-based AC method. Particular to an integrated MR-PET scanner, ignoring the RF coil attenuation can cause large underestimations (i.e. up to 50%) in the reconstructed images. Furthermore, the coil location in the PET field of view has to be accurately known. Good quality bone/air segmentation can be performed using the DUTE data. The PET images obtained using the MR-DUTE- and CT-based AC methods compare favorably in most of the brain structures. Conclusion An MR-DUTE-based AC

Toward implementing an MRI-based PET attenuation-correction method for neurologic studies on the MR-PET brain prototype.

Science.gov (United States)

Catana, Ciprian; van der Kouwe, Andre; Benner, Thomas; Michel, Christian J; Hamm, Michael; Fenchel, Matthias; Fischl, Bruce; Rosen, Bruce; Schmand, Matthias; Sorensen, A Gregory

2010-09-01

Several factors have to be considered for implementing an accurate attenuation-correction (AC) method in a combined MR-PET scanner. In this work, some of these challenges were investigated, and an AC method based entirely on the MRI data obtained with a single dedicated sequence was developed and used for neurologic studies performed with the MR-PET human brain scanner prototype. The focus was on the problem of bone-air segmentation, selection of the linear attenuation coefficient for bone, and positioning of the radiofrequency coil. The impact of these factors on PET data quantification was studied in simulations and experimental measurements performed on the combined MR-PET scanner. A novel dual-echo ultrashort echo time (DUTE) MRI sequence was proposed for head imaging. Simultaneous MR-PET data were acquired, and the PET images reconstructed using the proposed DUTE MRI-based AC method were compared with the PET images that had been reconstructed using a CT-based AC method. Our data suggest that incorrectly accounting for the bone tissue attenuation can lead to large underestimations (>20%) of the radiotracer concentration in the cortex. Assigning a linear attenuation coefficient of 0.143 or 0.151 cm(-1) to bone tissue appears to give the best trade-off between bias and variability in the resulting images. Not identifying the internal air cavities introduces large overestimations (>20%) in adjacent structures. On the basis of these results, the segmented CT AC method was established as the silver standard for the segmented MRI-based AC method. For an integrated MR-PET scanner, in particular, ignoring the radiofrequency coil attenuation can cause large underestimations (i.e., PET field of view has to be accurately known. High-quality bone-air segmentation can be performed using the DUTE data. The PET images obtained using the DUTE MRI- and CT-based AC methods compare favorably in most of

A retrospective comparison between 68Ga-DOTA-TOC PET/CT and 18F-DOPA PET/CT in patients with extra-adrenal paraganglioma.

Science.gov (United States)

Kroiss, Alexander; Putzer, Daniel; Frech, Andreas; Decristoforo, Clemens; Uprimny, Christian; Gasser, Rudolf Wolfgang; Shulkin, Barry Lynn; Url, Christoph; Widmann, Gerlig; Prommegger, Rupert; Sprinzl, Georg Mathias; Fraedrich, Gustav; Virgolini, Irene Johanna

2013-12-01

(18)F-Fluoro-L-dihydroxyphenylalanine ((18)F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by (68)Ga-DOTA-Tyr(3)-octreotide ((68)Ga-DOTA-TOC) PET. Therefore, we compared (68)Ga-DOTA-TOC and (18)F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard. A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with (68)Ga-DOTA-TOC PET and (18)F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUVmax) of each functional imaging modality in concordant tumour lesions was measured. Compared with anatomical imaging, (68)Ga-DOTA-TOC PET and (18)F-DOPA PET each had a per-patient and per-lesion detection rate of 100% in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of (68)Ga-DOTA-TOC was 100% and that of (18)F-DOPA PET was 56.0%. Overall, (68)Ga-DOTA-TOC PET identified 45 lesions; anatomical imaging identified 43 lesions, and (18)F-DOPA PET identified 32 lesions. The overall per-lesion detection rate of (68)Ga-DOTA-TOC PET was 100% (McNemar, P TOC PET and 11.8 ± 7.9 for (18)F-DOPA PET (Mann-Whitney U test, P TOC PET may be superior to (18)F-DOPA PET and diagnostic CT in providing valuable information for pretherapeutic staging of extra-adrenal PGL, particularly in surgically inoperable tumours and metastatic or multifocal disease.

SU-E-J-270: Study of PET Response to HDR Brachytherapy of Rectal Cancer

Energy Technology Data Exchange (ETDEWEB)

Hobbs, R; Le, Y; Armour, E; Efron, J; Azad, N; Wahl, R; Gearhart, S; Herman, J [Johns Hopkins University, Baltimore, MD (United States)

2014-06-01

Purpose: Dose-response studies in radiation therapy are typically using single response values for tumors across ensembles of tumors. Using the high dose rate (HDR) treatment plan dose grid and pre- and post-therapy FDG-PET images, we look for correlations between voxelized dose and FDG uptake response in individual tumors. Methods: Fifteen patients were treated for localized rectal cancer using 192Ir HDR brachytherapy in conjunction with surgery. FDG-PET images were acquired before HDR therapy and 6–8 weeks after treatment (prior to surgery). Treatment planning was done on a commercial workstation and the dose grid was calculated. The two PETs and the treatment dose grid were registered to each other using non-rigid registration. The difference in PET SUV values before and after HDR was plotted versus absorbed radiation dose for each voxel. The voxels were then separated into bins for every 400 cGy of absorbed dose and the bin average values plotted similarly. Results: Individual voxel doses did not correlate with PET response; however, when group into tumor subregions corresponding to dose bins, eighty percent of the patients showed a significant positive correlation (R2 > 0) between PET uptake difference in the targeted region and the absorbed dose. Conclusion: By considering larger ensembles of voxels, such as organ average absorbed dose or the dose bins considered here, valuable information may be obtained. The dose-response correlations as measured by FDG-PET difference potentially underlines the importance of FDG-PET as a measure of response, as well as the value of voxelized information.

False Discovery Rates in PET and CT Studies with Texture Features: A Systematic Review.

Directory of Open Access Journals (Sweden)

Anastasia Chalkidou

Full Text Available A number of recent publications have proposed that a family of image-derived indices, called texture features, can predict clinical outcome in patients with cancer. However, the investigation of multiple indices on a single data set can lead to significant inflation of type-I errors. We report a systematic review of the type-I error inflation in such studies and review the evidence regarding associations between patient outcome and texture features derived from positron emission tomography (PET or computed tomography (CT images.For study identification PubMed and Scopus were searched (1/2000-9/2013 using combinations of the keywords texture, prognostic, predictive and cancer. Studies were divided into three categories according to the sources of the type-I error inflation and the use or not of an independent validation dataset. For each study, the true type-I error probability and the adjusted level of significance were estimated using the optimum cut-off approach correction, and the Benjamini-Hochberg method. To demonstrate explicitly the variable selection bias in these studies, we re-analyzed data from one of the published studies, but using 100 random variables substituted for the original image-derived indices. The significance of the random variables as potential predictors of outcome was examined using the analysis methods used in the identified studies.Fifteen studies were identified. After applying appropriate statistical corrections, an average type-I error probability of 76% (range: 34-99% was estimated with the majority of published results not reaching statistical significance. Only 3/15 studies used a validation dataset. For the 100 random variables examined, 10% proved to be significant predictors of survival when subjected to ROC and multiple hypothesis testing analysis.We found insufficient evidence to support a relationship between PET or CT texture features and patient survival. Further fit for purpose validation of these

False Discovery Rates in PET and CT Studies with Texture Features: A Systematic Review.

Science.gov (United States)

Chalkidou, Anastasia; O'Doherty, Michael J; Marsden, Paul K

2015-01-01

A number of recent publications have proposed that a family of image-derived indices, called texture features, can predict clinical outcome in patients with cancer. However, the investigation of multiple indices on a single data set can lead to significant inflation of type-I errors. We report a systematic review of the type-I error inflation in such studies and review the evidence regarding associations between patient outcome and texture features derived from positron emission tomography (PET) or computed tomography (CT) images. For study identification PubMed and Scopus were searched (1/2000-9/2013) using combinations of the keywords texture, prognostic, predictive and cancer. Studies were divided into three categories according to the sources of the type-I error inflation and the use or not of an independent validation dataset. For each study, the true type-I error probability and the adjusted level of significance were estimated using the optimum cut-off approach correction, and the Benjamini-Hochberg method. To demonstrate explicitly the variable selection bias in these studies, we re-analyzed data from one of the published studies, but using 100 random variables substituted for the original image-derived indices. The significance of the random variables as potential predictors of outcome was examined using the analysis methods used in the identified studies. Fifteen studies were identified. After applying appropriate statistical corrections, an average type-I error probability of 76% (range: 34-99%) was estimated with the majority of published results not reaching statistical significance. Only 3/15 studies used a validation dataset. For the 100 random variables examined, 10% proved to be significant predictors of survival when subjected to ROC and multiple hypothesis testing analysis. We found insufficient evidence to support a relationship between PET or CT texture features and patient survival. Further fit for purpose validation of these image

Pharmacological studies of the lung with PET

International Nuclear Information System (INIS)

Syrota, A.

1986-10-01

Positron emission tomography (PET), known to be used for lung ventilation and perfusion studies, can also be used in pharmacology to obtain information that is otherwise not available. The lung takes up biologically active substances which can be inactivated or activated, and synthesises and releases others. Such information in man has been obtained from samples of human lungs, or from in vivo first-pass studies, invasive or not, as well as from in vivo kinetic studies using external detection methods with scintillation cameras. PET provides now quantitative regional data in the human lung

Injuries caused by pets in Asian urban households: a cross-sectional telephone survey

Science.gov (United States)

Chan, Emily Y Y; Gao, Yang; Li, Liping; Lee, Po Yi

2017-01-01

Objectives Little is known about pet-related injuries in Asian populations. This study primarily aimed to investigate the incidence rate of pet-related household injuries in Hong Kong, an urban Chinese setting. Setting Cantonese-speaking non-institutionalised population of all ages in Hong Kong accessible by telephone land-line. Participants A total of 43 542 telephone numbers were dialled and 6570 residents successfully completed the interviews. Primary and secondary outcome measures Data of pet-related household injuries in the previous 12 months, pet ownership and socio-demographic characteristics were collected with a questionnaire. Direct standardisation of the incidence rates of pet-related household injuries by gender and age to the 2009 Hong Kong Population Census was estimated. Univariate and multivariate analyses were performed to estimate risks of socio-demographic factors and pet ownership for the injury. Results A total of 84 participants experienced pet-related household injuries in the past 12 months, with an overall person-based incidence rate of 1.28%. The majority of the victims were injured once (69.6%). Cats (51.6%) were the most common pets involved. Pet owners were at an extremely higher risk after controlling for other factors (adjusted OR: 52.0, 95% CI 22.1 to 98.7). Females, the unmarried, those with higher monthly household income and those living in lower-density housing were more likely to be injured by pets. Conclusions We project a pet-related household injury incidence rate of 1.24% in the general Hong Kong population, with 86 334 residents sustaining pet-related injuries every year. Pet ownership puts people at extremely high risk, especially the unmarried. Further studies should focus on educating pet owners to reduce pet-related injuries in urban Greater China. PMID:28110284

Comparing sensitivity and count rate performance of small-bore DOI-PET scanners by computer simulation

International Nuclear Information System (INIS)

Kobayashi, Tetsuya; Takahashi, Hisashi; Yamaya, Taiga; Murayama, Hideo; Kitamura, Keishi; Hasegawa, Tomoyuki; Suga, Mikio

2006-01-01

In the development of a dedicated small-bore DOI-PET scanner for small animals (jPET-RD), we performed Monte Carlo simulations using the GATE based on Geant4 and investigated the influence of the proximity of the detectors to the target object on the sensitivity and count rate performance. The jPET-RD is based on a large-size depth-of-interaction (DOI) block detector that consists of a 4-layered array of 32 x 32 LSO crystals (1.4 mm x 1.4 mm x 4.5 mm) and a 256-ch flat panel position-sensitive photomultiplier tube. In this work, three detector geometries were simulated: two rings of six detector blocks arranged in a hexagonal pattern (FOV 85 mm in diameter) and four detector blocks arranged in a tetragonal pattern (FOV 49 mm in diameter) and in an overlapped tetragonal pattern (FOV 38 mm in diameter). The simulation results showed that the smaller bore geometry can provide higher sensitivity because of its larger solid angle. Although it clearly affected the noise equivalent count rate (NECR) due to its high dead-time, parallel readout with appropriate anode segmentation improved the NECR at 20 MBq by a factor of 1.1 to 1.4 compared with the case of 256-ch anodes read out by one front-end circuit. (author)

Combined early dynamic (18)F-FDG PET/CT and conventional whole-body (18)F-FDG PET/CT provide one-stop imaging for detecting hepatocellular carcinoma.

Science.gov (United States)

Wang, Shao-Bo; Wu, Hu-Bing; Wang, Quan-Shi; Zhou, Wen-Lan; Tian, Ying; Li, Hong-Sheng; Ji, Yun-Hai; Lv, Liang

2015-06-01

It is widely accepted that conventional (18)F-FDG PET/CT (whole-body static (18)F-FDG PET/CT, WB (18)F-FDG PET/CT) has a low detection rate for hepatocellular carcinoma (HCC). We prospectively assessed the role of early dynamic (18)F-FDG PET/CT (ED (18)F-FDG PET/CT) and WB (18)F-FDG PET/CT in detecting HCC, and we quantified the added value of ED (18)F-FDG PET/CT to WB (18)F-FDG PET/CT. Twenty-two patients with 37 HCC tumors (HCCs) who underwent both a liver ED (18)F-FDG PET/CT (performed simultaneously with a 5.5 MBq/kg (18)F-FDG bolus injection and continued for 240 s) and a WB (18)F-FDG PET/CT were enrolled in the study. The WB (18)F-FDG PET/CT and ED (18)F-FDG PET/CT scans were positive in 56.7% (21/37) and 78.4% (29/37) HCCs, respectively (PPET/CT in conjunction with WB (18)F-FDG PET/CT (one-stop (18)F-FDG PET/CT) improved the positive detection rates of WB and ED (18)F-FDG PET/CT alone from 56.7% and 78.4% to 91.9% (34/37) (P0.05, respectively). One-stop (18)F-FDG PET/CT appears to be useful to improve WB (18)F-FDG PET/CT for HCC detection. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Noninvasive and simple method for the estimation of myocardial metabolic rate of glucose by PET and 18F-FDG

International Nuclear Information System (INIS)

Takahashi, Norio; Tamaki, Nagara; Kawamoto, Masahide

1994-01-01

To estimate regional myocardial metabolic rate of glucose (rMRGlu) with positron emission tomography (PET) and 2-[ 18 F] fluoro-2-deoxy-D-glucose (FDG), non invasive simple method has been investigated using dynamic PET imaging in 14 patients with ischemic heart disease. This imaging approach uses a blood time-activity curve (TAC) derived from a region of interest (ROI) drawn over dynamic PET images of the left ventricle (LV), left atrium (LA) and aorta. Patlak graphic analysis was used to estimate k 1 k 3 /(k 2 +k 3 ) from serial plasma and myocardial radioactivities. FDG counts ratio between whole blood and plasma was relatively constant (0.91±0.02) both throughout the time and among different patients. Although TACs derived from dynamic PET images gradually increased at later phase due to spill over from the myocardium into the cavity, three were good agreements between the estimated K complex values obtained from arterial blood sampling and dynamic PET imaging (LV r=0.95, LA r=0.96, aorta r=0.98). These results demonstrate the practical usefulness of a simplified and noninvasive method for the estimation of rMRGlu in humans by PET. (author)

Additive value of amyloid-PET in routine cases of clinical dementia work-up after FDG-PET

International Nuclear Information System (INIS)

Brendel, Matthias; Schnabel, Jonas; Wagner, Leonie; Brendel, Eva; Meyer-Wilmes, Johanna; Unterrainer, Marcus; Schoenecker, Sonja; Prix, Catharina; Ackl, Nibal; Schildan, Andreas; Patt, Marianne; Barthel, Henryk; Sabri, Osama; Catak, Cihan; Pogarell, Oliver; Levin, Johannes; Danek, Adrian; Buerger, Katharina; Bartenstein, Peter; Rominger, Axel

2017-01-01

In recent years, several [ 18 F]-labeled amyloid-PET tracers have been developed and have obtained clinical approval. Despite their widespread scientific use, studies in routine clinical settings are limited. We therefore investigated the impact of [ 18 F]-florbetaben (FBB)-PET on the diagnostic management of patients with suspected dementia that was still unclarified after [ 18 F]-fluordeoxyglucose (FDG)-PET. All subjects were referred in-house with a suspected dementia syndrome due to neurodegenerative disease. After undergoing an FDG-PET exam, the cases were discussed by the interdisciplinary dementia board, where the most likely diagnosis as well as potential differential diagnoses were documented. Because of persistent diagnostic uncertainty, the patients received an additional FBB-PET exam. Results were interpreted visually and classified as amyloid-positive or amyloid-negative, and we then compared the individual clinical diagnoses before and after additional FBB-PET. A total of 107 patients (mean age 69.4 ± 9.7y) were included in the study. The FBB-PET was rated as amyloid-positive in 65/107. In 83% of the formerly unclear cases, a final diagnosis was reached through FBB-PET, and the most likely prior diagnosis was changed in 28% of cases. The highest impact was observed for distinguishing Alzheimer's dementia (AD) from fronto-temporal dementia (FTLD), where FBB-PET altered the most likely diagnosis in 41% of cases. FBB-PET has a high additive value in establishing a final diagnosis in suspected dementia cases when prior investigations such as FDG-PET are inconclusive. The differentiation between AD and FTLD was particularly facilitated by amyloid-PET, predicting a considerable impact on patient management, especially in the light of upcoming disease-modifying therapies. (orig.)

Additive value of amyloid-PET in routine cases of clinical dementia work-up after FDG-PET

Energy Technology Data Exchange (ETDEWEB)

Brendel, Matthias; Schnabel, Jonas; Wagner, Leonie; Brendel, Eva; Meyer-Wilmes, Johanna; Unterrainer, Marcus [University Hospital, LMU Munich, Department of Nuclear Medicine, Munich (Germany); Schoenecker, Sonja; Prix, Catharina; Ackl, Nibal [University Hospital, LMU Munich, Department of Neurology, Munich (Germany); Schildan, Andreas; Patt, Marianne; Barthel, Henryk; Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Catak, Cihan [Klinikum der Universitaet Muenchen, Institute for Stroke and Dementia Research, Munich (Germany); Pogarell, Oliver [University Hospital, LMU Munich, Department of Psychiatry, Munich (Germany); Levin, Johannes; Danek, Adrian [University Hospital, LMU Munich, Department of Neurology, Munich (Germany); DZNE - German Center for Neurodegenerative Diseases, Munich (Germany); Buerger, Katharina [Klinikum der Universitaet Muenchen, Institute for Stroke and Dementia Research, Munich (Germany); DZNE - German Center for Neurodegenerative Diseases, Munich (Germany); Bartenstein, Peter; Rominger, Axel [University Hospital, LMU Munich, Department of Nuclear Medicine, Munich (Germany); Munich Cluster for Systems Neurology (SyNergy), Munich (Germany)

2017-12-15

In recent years, several [{sup 18}F]-labeled amyloid-PET tracers have been developed and have obtained clinical approval. Despite their widespread scientific use, studies in routine clinical settings are limited. We therefore investigated the impact of [{sup 18}F]-florbetaben (FBB)-PET on the diagnostic management of patients with suspected dementia that was still unclarified after [{sup 18}F]-fluordeoxyglucose (FDG)-PET. All subjects were referred in-house with a suspected dementia syndrome due to neurodegenerative disease. After undergoing an FDG-PET exam, the cases were discussed by the interdisciplinary dementia board, where the most likely diagnosis as well as potential differential diagnoses were documented. Because of persistent diagnostic uncertainty, the patients received an additional FBB-PET exam. Results were interpreted visually and classified as amyloid-positive or amyloid-negative, and we then compared the individual clinical diagnoses before and after additional FBB-PET. A total of 107 patients (mean age 69.4 ± 9.7y) were included in the study. The FBB-PET was rated as amyloid-positive in 65/107. In 83% of the formerly unclear cases, a final diagnosis was reached through FBB-PET, and the most likely prior diagnosis was changed in 28% of cases. The highest impact was observed for distinguishing Alzheimer's dementia (AD) from fronto-temporal dementia (FTLD), where FBB-PET altered the most likely diagnosis in 41% of cases. FBB-PET has a high additive value in establishing a final diagnosis in suspected dementia cases when prior investigations such as FDG-PET are inconclusive. The differentiation between AD and FTLD was particularly facilitated by amyloid-PET, predicting a considerable impact on patient management, especially in the light of upcoming disease-modifying therapies. (orig.)

Predictive value of {sup 18}F-FDG PET/CT in restaging patients affected by ovarian carcinoma: a multicentre study

Energy Technology Data Exchange (ETDEWEB)

Caobelli, Federico [Medizinische Hochschule Hannover, Klinik fuer Nuklearmedizin, Hanover (Germany); Alongi, Pierpaolo [University of Milano-Bicocca, Nuclear Medicine Unit, Milan (Italy); IRCSS San Raffaele Scientific Institute, Nuclear Medicine Department, Milan (Italy); Evangelista, Laura; Saladini, Giorgio [Veneto Institute of Oncology IOV - IRCCS, Radiotherapy and Nuclear Medicine Unit, Padua (Italy); Picchio, Maria [IRCSS San Raffaele Scientific Institute, Nuclear Medicine Department, Milan (Italy); Rensi, Marco; Geatti, Onelio [Hospital of Udine, Nuclear Medicine Department, Udine (Italy); Castello, Angelo; Laghai, Iashar [University of Florence, Nuclear Medicine Department, Florence (Italy); Popescu, Cristina E. [Niguarda Ca' Granda Hospital, Nuclear Medicine Department, Milan (Italy); Dolci, Carlotta; Crivellaro, Cinzia [University of Milan-Bicocca, Nuclear Medicine Department, San Gerardo Hospital, Tecnomed Foundation, Milan (Italy); Seghezzi, Silvia [Hospital of Treviglio, Nuclear Medicine Department, Treviglio, Bergamo (Italy); Kirienko, Margarita [University of Milano-Bicocca, Nuclear Medicine Unit, Milan (Italy); De Biasi, Vincenzo [Nuclear Medicine Department, Arcispedale Santa Maria Nuova, Reggio Emilia (Italy); Cocciolillo, Fabrizio [Catholic University of the Sacred Heart, Nuclear Medicine Department, Rome (Italy); Quartuccio, Natale [University of Messina, Nuclear Medicine Unit, Department of Biomedical Sciences and of Morphological and Functional Images, Messina (Italy); Collaboration: Young AIMN Working Group

2016-03-15

Ovarian cancer is the eighth most common malignancy among women and has a high mortality rate. Prognostic factors able to drive an effective therapy are essential. {sup 18}F-Fluoro-2-deoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) has been investigated in patients with epithelial ovarian cancer and showed promise in diagnosing, staging, detecting recurrent lesions and monitoring treatment response. Conversely, its prognostic role remains unclear. We aimed at assessing the prognostic value of {sup 18}F-FDG PET/CT performed in the restaging process in a multicentre study. We evaluated 168 patients affected by ovarian carcinoma, who underwent a restaging {sup 18}F-FDG PET/CT. The presence of local recurrences, lymph node involvement and distant metastasis was recorded as well as lesion dimensions, maximum and mean standardized uptake values (SUV{sub max} and SUV{sub mean}, respectively). Progression-free survival (PFS) and overall survival (OS) at 3 and 4 years were computed by using Kaplan-Meier curves. Increased odds ratio was assessed using Cox regression analysis testing all lesion parameters measured by PET/CT. PFS was significantly longer in patients with a negative than a positive restaging PET/CT study (3- and 4-year PFS 64 and 53 % vs 23 and 12 %, respectively; p < 0.001). Similarly, a negative study was associated with a significantly higher OS rate after 4 years of follow-up (67 vs 25 % in negative and positive groups, respectively; p < 0.001). Lymph node or distant involvement were also independently associated with an increased risk of disease progression [hazard ratio (HR) 1.6 and 2.2, respectively; p = 0.003]. Moreover, PET/CT showed an incremental prognostic value compared to the International Federation of Gynecology and Obstetrics (FIGO) staging system. In the analysis of patient subsets, individuals with the same FIGO stage I-II but with negative PET had a significantly better 4-year OS than patients with low

Approaches using molecular imaging technology -- use of PET in clinical microdose studies.

Science.gov (United States)

Wagner, Claudia C; Langer, Oliver

2011-06-19

Positron emission tomography (PET) imaging uses minute amounts of radiolabeled drug tracers and thereby meets the criteria for clinical microdose studies. The advantage of PET, when compared to other analytical methods used in microdose studies, is that the pharmacokinetics (PK) of a drug can be determined in the tissue targeted for drug treatment. PET microdosing already offers interesting applications in clinical oncology and in the development of central nervous system pharmaceuticals and is extending its range of application to many other fields of pharmaceutical medicine. Although requirements for preclinical safety testing for microdose studies have been cut down by regulatory authorities, radiopharmaceuticals increasingly need to be produced under good manufacturing practice (GMP) conditions, which increases the costs of PET microdosing studies. Further challenges in PET microdosing include combining PET with other ultrasensitive analytical methods, such as accelerator mass spectrometry (AMS), to gain plasma PK data of drugs, beyond the short PET examination periods. Finally, conducting clinical PET studies with radiolabeled drugs both at micro- and therapeutic doses is encouraged to answer the question of dose linearity in clinical microdosing. Copyright © 2010 Elsevier B.V. All rights reserved.

Clinical usefulness of PET in the management of oral cancer. Comparison between FDG-PET and MET-PET

International Nuclear Information System (INIS)

Kitagawa, Yoshimasa; Saitoh, Masaaki; Nakamura, Mikiko

2007-01-01

Inductive chemoradiotherapy has played an important role in preserving organs and functions in patients with oral squamous cell carcinoma (SCC). To determine whether a reduced form of surgery should be performed after chemoradiotherapy, accurate evaluation of residual tumor cells is essential. We investigated the clinical value of positron emission tomography with 18 F labeled fluorodeoxyglucose (FDG-PET) in the management of oral SCCs. Forty-five patients underwent two FDG-PET studies, one prior to and one at 6 weeks after the chemoradiotherapy. Pretreatment FDG-PET was useful in predicting the response to treatment. Posttreatment FDG-PET could evaluate residual viable cells and prognosis. Organ preservation may be feasible based on PET evaluation. Hence FDG-PET is a valuable tool in the treatment of oral cancer. 11 C-Methionine (MET) is another promising tracer for PET that can be used to assess metabolic demand for amino acids in cancer cells. A MET-PET and FDG-PET study was performed during the same period to investigate diagnostic accuracy in 40 oral malignancies. Sensitivity and positive predictive value of MET-PET were 95% and 100%, respectively, and were comparable with those of FDG-PET. Further study is required to determine the diagnostic significance of MET-PET in evaluating response to chemoradiotherapy. (author)

A retrospective comparison between 68Ga-DOTA-TOC PET/CT and 18F-DOPA PET/CT in patients with extra-adrenal paraganglioma

International Nuclear Information System (INIS)

Kroiss, Alexander; Putzer, Daniel; Decristoforo, Clemens; Uprimny, Christian; Virgolini, Irene Johanna; Frech, Andreas; Fraedrich, Gustav; Gasser, Rudolf Wolfgang; Shulkin, Barry Lynn; Url, Christoph; Widmann, Gerlig; Prommegger, Rupert; Sprinzl, Georg Mathias

2013-01-01

18 F-Fluoro-l-dihydroxyphenylalanine ( 18 F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by 68 Ga-DOTA-Tyr 3 -octreotide ( 68 Ga-DOTA-TOC) PET. Therefore, we compared 68 Ga-DOTA-TOC and 18 F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard. A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with 68 Ga-DOTA-TOC PET and 18 F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUV max ) of each functional imaging modality in concordant tumour lesions was measured. Compared with anatomical imaging, 68 Ga-DOTA-TOC PET and 18 F-DOPA PET each had a per-patient and per-lesion detection rate of 100 % in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of 68 Ga-DOTA-TOC was 100 % and that of 18 F-DOPA PET was 56.0 %. Overall, 68 Ga-DOTA-TOC PET identified 45 lesions; anatomical imaging identified 43 lesions, and 18 F-DOPA PET identified 32 lesions. The overall per-lesion detection rate of 68 Ga-DOTA-TOC PET was 100 % (McNemar, P 18 F-DOPA PET was 71.1 % (McNemar, P max (mean ± SD) of all 32 concordant lesions was 67.9 ± 61.5 for 68 Ga-DOTA-TOC PET and 11.8 ± 7.9 for 18 F-DOPA PET (Mann-Whitney U test, P 68 Ga-DOTA-TOC PET may be superior to 18 F-DOPA PET and diagnostic CT in providing valuable information for pretherapeutic staging of extra-adrenal PGL, particularly in surgically

Evaluation of 68Ga-DOTATOC PET/MRI for whole-body staging of neuroendocrine tumours in comparison with 68Ga-DOTATOC PET/CT.

Science.gov (United States)

Sawicki, Lino M; Deuschl, Cornelius; Beiderwellen, Karsten; Ruhlmann, Verena; Poeppel, Thorsten D; Heusch, Philipp; Lahner, Harald; Führer, Dagmar; Bockisch, Andreas; Herrmann, Ken; Forsting, Michael; Antoch, Gerald; Umutlu, Lale

2017-10-01

To compare the diagnostic performance of 68 Ga-DOTATOC PET/MRI and 68 Ga-DOTATOC PET/CT in the whole-body staging of patients with neuroendocrine tumours (NET). Thirty patients with histopathologically confirmed NET underwent PET/CT and PET/MRI in a single-injection protocol. PET/CT and PET/MRI scans were prospectively evaluated with regard to lesion count, localization, nature (NET/non-NET), and conspicuity (four-point scale). Histopathology and follow-up imaging served as the reference standards. The proportions of NET and non-NET lesions rated correctly were compared using McNemar's chi-squared test. The Wilcoxon test was used to assess differences in SUVmax and lesion conspicuity. The correlation between the SUVmax for the same lesions from each modality was analysed using Pearson's correlation coefficient (r). According to the reference standard, there were 197 lesions (142 NET, 55 non-NET). Lesion-based analysis showed a higher proportion of correctly rated NET lesions on PET/MRI than on PET/CT (90.8% vs. 86.7%, p = 0.031), whereas on PET/CT there was a higher proportion of correctly rated non-NET lesions (94.5% vs. 83.6%, p = 0.031). SUVmax was strongly correlated (r = 0.86; p PET/MRI (both p PET/MRI yielded a higher proportion of correctly rated NET lesions and should be regarded as a valuable alternative to 68 Ga-DOTATOC PET/CT in whole-body staging of NET patients. • 68 Ga-DOTATOC PET/MRI correctly identified more NET lesions than 68 Ga-DOTATOC PET/CT. • 68 Ga-DOTATOC PET/MRI provides better NET lesion conspicuity than 68 Ga-DOTATOC PET/CT. • SUVmax values from the two modalities are strongly correlated and do not differ significantly.

Reproducibility of Quantitative Brain Imaging Using a PET-Only and a Combined PET/MR System

Directory of Open Access Journals (Sweden)

Martin L. Lassen

2017-07-01

Full Text Available The purpose of this study was to test the feasibility of migrating a quantitative brain imaging protocol from a positron emission tomography (PET-only system to an integrated PET/MR system. Potential differences in both absolute radiotracer concentration as well as in the derived kinetic parameters as a function of PET system choice have been investigated. Five healthy volunteers underwent dynamic (R-[11C]verapamil imaging on the same day using a GE-Advance (PET-only and a Siemens Biograph mMR system (PET/MR. PET-emission data were reconstructed using a transmission-based attenuation correction (AC map (PET-only, whereas a standard MR-DIXON as well as a low-dose CT AC map was applied to PET/MR emission data. Kinetic modeling based on arterial blood sampling was performed using a 1-tissue-2-rate constant compartment model, yielding kinetic parameters (K1 and k2 and distribution volume (VT. Differences for parametric values obtained in the PET-only and the PET/MR systems were analyzed using a 2-way Analysis of Variance (ANOVA. Comparison of DIXON-based AC (PET/MR with emission data derived from the PET-only system revealed average inter-system differences of −33 ± 14% (p < 0.05 for the K1 parameter and −19 ± 9% (p < 0.05 for k2. Using a CT-based AC for PET/MR resulted in slightly lower systematic differences of −16 ± 18% for K1 and −9 ± 10% for k2. The average differences in VT were −18 ± 10% (p < 0.05 for DIXON- and −8 ± 13% for CT-based AC. Significant systematic differences were observed for kinetic parameters derived from emission data obtained from PET/MR and PET-only imaging due to different standard AC methods employed. Therefore, a transfer of imaging protocols from PET-only to PET/MR systems is not straightforward without application of proper correction methods.Clinical Trial Registration:www.clinicaltrialsregister.eu, identifier 2013-001724-19

Assessment of myocardial metabolic rate of glucose by means of Bayesian ICA and Markov Chain Monte Carlo methods in small animal PET imaging

Science.gov (United States)

Berradja, Khadidja; Boughanmi, Nabil

2016-09-01

In dynamic cardiac PET FDG studies the assessment of myocardial metabolic rate of glucose (MMRG) requires the knowledge of the blood input function (IF). IF can be obtained by manual or automatic blood sampling and cross calibrated with PET. These procedures are cumbersome, invasive and generate uncertainties. The IF is contaminated by spillover of radioactivity from the adjacent myocardium and this could cause important error in the estimated MMRG. In this study, we show that the IF can be extracted from the images in a rat heart study with 18F-fluorodeoxyglucose (18F-FDG) by means of Independent Component Analysis (ICA) based on Bayesian theory and Markov Chain Monte Carlo (MCMC) sampling method (BICA). Images of the heart from rats were acquired with the Sherbrooke small animal PET scanner. A region of interest (ROI) was drawn around the rat image and decomposed into blood and tissue using BICA. The Statistical study showed that there is a significant difference (p corrupted with spillover.

Comparison of 18F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

International Nuclear Information System (INIS)

Verger, Antoine; Filss, Christian P.; Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena; Sabel, Michael; Wittsack, Hans J.; Galldiks, Norbert; Fink, Gereon R.; Shah, Nadim J.; Langen, Karl-Josef

2017-01-01

Both perfusion-weighted MR imaging (PWI) and O-(2- 18 F-fluoroethyl)-L-tyrosine PET ( 18 F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of 18 F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with 18 F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR mean , TBR max ) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for 18 F-FET PET. Diagnostic accuracies of 18 F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of 18 F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR mean and TBR max of 18 F-FET PET uptake (0.80, 0.83) and for TBR mean and TBR max of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both 18 F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by 18 F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

A combined microdialysis and FDG-PET study of glucose metabolism in head injury.

Science.gov (United States)

Hutchinson, Peter J; O'Connell, Mark T; Seal, Alex; Nortje, Jurgens; Timofeev, Ivan; Al-Rawi, Pippa G; Coles, Jonathan P; Fryer, Timothy D; Menon, David K; Pickard, John D; Carpenter, Keri L H

2009-01-01

Microdialysis continuously monitors the chemistry of a small focal volume of the cerebral extracellular space. Positron emission tomography (PET) establishes metabolism of the whole brain but only for the scan's duration. This study's objective was to apply these techniques together, in patients with traumatic brain injury, to assess the relationship between microdialysis (extracellular glucose, lactate, pyruvate, and the lactate/pyruvate (L/P) ratio as a marker of anaerobic metabolism) and PET parameters of glucose metabolism using the glucose analogue [(18)F]-fluorodeoxyglucose (FDG). In particular, we aimed to determine the fate of glucose in terms of differential metabolism to pyruvate and lactate. Microdialysis catheters (CMA70 or CMA71) were inserted into the cerebral cortex of 17 patients with major head injury. Microdialysis was performed during FDG-PET scans with regions of interest for PET analysis defined by the location of the gold-tipped microdialysis catheter. Microdialysate analysis was performed on a CMA600 analyser. There was significant linear relationship between the PET-derived parameter of glucose metabolism (regional cerebral metabolic rate of glucose; CMRglc) and levels of lactate (r = 0.778, p glucose was metabolised to both lactate and pyruvate, but was not associated with an increase in the L/P ratio. This suggests an increase in glucose metabolism to both lactate and pyruvate, as opposed to a shift towards anaerobic metabolism.

Brain activation studies with PET and functional MRI

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Yonekura, Yoshiharu [Fukui Medical Univ., Matsuoka (Japan). Biomedical Imaging Research Center; Sadato, Norihiro [Okazaki National Research Inst., Aichi (Japan). National Inst. for Physiological Sciences

2002-01-01

Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H{sub 2}{sup 15}O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H{sub 2}{sup 15}O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

Brain activation studies with PET and functional MRI

International Nuclear Information System (INIS)

Yonekura, Yoshiharu; Sadato, Norihiro

2002-01-01

Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H 2 15 O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H 2 15 O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

PET and PET/CT in tumour of undetermined origin; PET y PET/CT en tumor de origen indeterminado

Energy Technology Data Exchange (ETDEWEB)

Garcia O, J R [Nuclear Medicine and Molecular Imaging, PET/CT, Centro Medico ABC, Mexico D.F. (Mexico)

2007-07-01

In this presentation the following conclusions were obtained regarding the use of PET and PET/CT in patient with cancer of unknown primary: 1. Detection of the primary one in 1/3 at 1/2 of patient. 2. It detects metastases in other places in 50%. 3. It changes the initial therapy planned in 1/3 at 1/2 of patient. 4. Useful in initial phases of protocol study to limit the other procedures. After standard evaluation. Before advanced protocol. 5. PET/CT study increases the % of primary detection, although in a non significant way vs. PET. 6. They are required more studies to value their utility to a more objective manner. (Author)

A study on client needs regarding FDG-PET for cancer screening

International Nuclear Information System (INIS)

Yamane, Tomohiko; Yoshiya, Kazuhiko; Nagata, Takeshi; Ito, Shinichi; Ito, Satoshi; Mezaki, Yukio; Uchida, Hideo

2006-01-01

We researched client needs regarding FDG-PET for cancer screening. The study included 1,527 individuals who underwent FDG-PET for cancer screening at our hospital. An interview sheet was distributed after injecting FDG. Clients listed the organs that required examination and the symptoms causing them anxiety. Results indicated that 9.8% of the clients listed organs for which FDG-PET would not be useful in detecting cancer. This study suggested that there exists a gap between client needs and FDG-PET utility; hence we need improved methods of providing correct information to clients. (author)

Effects of attenuation and scatter corrections in cat brain PET images using microPET R4 scanner

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Lee, Jong Jin

2006-01-01

The aim of this study was to examine the effects of attenuation correction (AC) and scatter correction (SC) on the quantification of PET count rates. To assess the effects of AC and SC, 18 F-FDG PET images of phantom and cat brain were acquired using microPET R4 scanner. Thirty-minute transmission images using 68 Ge source and emission images after injection of FDG were acquired. PET images were reconstructed using. 2D OSEM. AC and SC were applied. Regional count rates were measured using ROls drawn on cerebral cortex including frontal, parietal, and latral temporal lobes and deep gray matter including head of caudate nucleus, putamen and thalamus for pre- and post-AC and SC images. The count rates were then normalized with the injected dose per body weight. To assess the effects of AC, count ratio of 'deep gray matter/cerebral cortex' was calculated. To assess the effects of SC, ROls were also drawn on the gray matter (GM) and white matter (WM), and contrast between them ((GM-WM)/GM) was measured. After the AC, count ratio of 'deep gray matter/cerebral cortex' was increased by 17±7%. After the SC, contrast was also increased by 12±3%. Relative count of deep gray matter and contrast between gray and white matters were increased after AC and SC, suggesting that the AC would be critical for the quantitative analysis of cat brain PET data

Combined Modality Treatment for PET-Positive Non-Hodgkin Lymphoma: Favorable Outcomes of Combined Modality Treatment for Patients With Non-Hodgkin Lymphoma and Positive Interim or Postchemotherapy FDG-PET

Energy Technology Data Exchange (ETDEWEB)

Halasz, Lia M. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Jacene, Heather A. [Department of Imaging, Dana-Farber Cancer Institute, and Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Catalano, Paul J. [Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Van den Abbeele, Annick D. [Department of Imaging, Dana-Farber Cancer Institute, and Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); LaCasce, Ann [Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Mauch, Peter M. [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Ng, Andrea K., E-mail: ang@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Boston, Massachusetts (United States)

2012-08-01

Purpose: To evaluate outcomes of patients treated for aggressive non-Hodgkin lymphoma (NHL) with combined modality therapy based on [{sup 18}F]fluoro-2-deoxy-2-D-glucose positron emission tomography (FDG-PET) response. Methods and Materials: We studied 59 patients with aggressive NHL, who received chemotherapy and radiation therapy (RT) from 2001 to 2008. Among them, 83% of patients had stage I/II disease. Patients with B-cell lymphoma received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone)-based chemotherapy, and 1 patient with anaplastic lymphoma kinase-negative anaplastic T-cell lymphoma received CHOP therapy. Interim and postchemotherapy FDG-PET or FDG-PET/computed tomography (CT) scans were performed for restaging. All patients received consolidated involved-field RT. Median RT dose was 36 Gy (range, 28.8-50 Gy). Progression-free survival (PFS) and local control (LC) rates were calculated with and without a negative interim or postchemotherapy FDG-PET scan. Results: Median follow-up was 46.5 months. Thirty-nine patients had negative FDG-PET results by the end of chemotherapy, including 12 patients who had a negative interim FDG-PET scan and no postchemotherapy PET. Twenty patients were FDG-PET-positive, including 7 patients with positive interim FDG-PET and no postchemotherapy FDG-PET scans. The 3-year actuarial PFS rates for patients with negative versus positive FDG-PET scans were 97% and 90%, respectively. The 3-year actuarial LC rates for patients with negative versus positive FDG-PET scans were 100% and 90%, respectively. Conclusions: Patients who had a positive interim or postchemotherapy FDG-PET had a PFS rate of 90% at 3 years after combined modality treatment, suggesting that a large proportion of these patients can be cured with consolidated RT.

Monte Carlo simulations in small animal PET imaging

Energy Technology Data Exchange (ETDEWEB)

Branco, Susana [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)], E-mail: susana.silva@fc.ul.pt; Jan, Sebastien [Service Hospitalier Frederic Joliot, CEA/DSV/DRM, Orsay (France); Almeida, Pedro [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)

2007-10-01

This work is based on the use of an implemented Positron Emission Tomography (PET) simulation system dedicated for small animal PET imaging. Geant4 Application for Tomographic Emission (GATE), a Monte Carlo simulation platform based on the Geant4 libraries, is well suited for modeling the microPET FOCUS system and to implement realistic phantoms, such as the MOBY phantom, and data maps from real examinations. The use of a microPET FOCUS simulation model with GATE has been validated for spatial resolution, counting rates performances, imaging contrast recovery and quantitative analysis. Results from realistic studies of the mouse body using {sup -}F and [{sup 18}F]FDG imaging protocols are presented. These simulations include the injection of realistic doses into the animal and realistic time framing. The results have shown that it is possible to simulate small animal PET acquisitions under realistic conditions, and are expected to be useful to improve the quantitative analysis in PET mouse body studies.

Approaches using molecular imaging technology - use of PET in clinical microdose studies§

Science.gov (United States)

Wagner, Claudia C; Langer, Oliver

2013-01-01

Positron emission tomography (PET) imaging uses minute amounts of radiolabeled drug tracers and thereby meets the criteria for clinical microdose studies. The advantage of PET, when compared to other analytical methods used in microdose studies, is that the pharmacokinetics (PK) of a drug can be determined in the tissue targeted for drug treatment. PET microdosing already offers interesting applications in clinical oncology and in the development of central nervous system pharmaceuticals and is extending its range of application to many other fields of pharmaceutical medicine. Although requirements for preclinical safety testing for microdose studies have been cut down by regulatory authorities, radiopharmaceuticals increasingly need to be produced under good manufacturing practice (GMP) conditions, which increases the costs of PET microdosing studies. Further challenges in PET microdosing include combining PET with other ultrasensitive analytical methods, such as accelerator mass spectrometry (AMS), to gain plasma PK data of drugs, beyond the short PET examination periods. Finally, conducting clinical PET studies with radiolabeled drugs both at micro- and therapeutic doses is encouraged to answer the question of dose linearity in clinical microdosing. PMID:20887762

Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT

International Nuclear Information System (INIS)

Wiesmueller, Marco; Schmidt, Daniela; Beck, Michael; Kuwert, Torsten; Gall, Carl C. von; Quick, Harald H.; Navalpakkam, Bharath; Lell, Michael M.; Uder, Michael; Ritt, Philipp

2013-01-01

PET/MR hybrid scanners have recently been introduced, but not yet validated. The aim of this study was to compare the PET components of a PET/CT hybrid system and of a simultaneous whole-body PET/MR hybrid system with regard to reproducibility of lesion detection and quantitation of tracer uptake. A total of 46 patients underwent a whole-body PET/CT scan 1 h after injection and an average of 88 min later a second scan using a hybrid PET/MR system. The radioactive tracers used were 18 F-deoxyglucose (FDG), 18 F-ethylcholine (FEC) and 68 Ga-DOTATATE (Ga-DOTATATE). The PET images from PET/CT (PET CT ) and from PET/MR (PET MR ) were analysed for tracer-positive lesions. Regional tracer uptake in these foci was quantified using volumes of interest, and maximal and average standardized uptake values (SUV max and SUV avg , respectively) were calculated. Of the 46 patients, 43 were eligible for comparison and statistical analysis. All lesions except one identified by PET CT were identified by PET MR (99.2 %). In 38 patients (88.4 %), the same number of foci were identified by PET CT and by PET MR . In four patients, more lesions were identified by PET MR than by PET CT , in one patient PET CT revealed an additional focus compared to PET MR . The mean SUV max and SUV avg of all lesions determined by PET MR were by 21 % and 11 % lower, respectively, than the values determined by PET CT (p CT and PET MR were minor, but statistically significant. Nevertheless, a more detailed study of the quantitative accuracy of PET MR and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations. (orig.)

Improving the singles rate method for modeling accidental coincidences in high-resolution PET

International Nuclear Information System (INIS)

Oliver, Josep F; Rafecas, Magdalena

2010-01-01

Random coincidences ('randoms') are one of the main sources of image degradation in PET imaging. In order to correct for this effect, an accurate method to estimate the contribution of random events is necessary. This aspect becomes especially relevant for high-resolution PET scanners where the highest image quality is sought and accurate quantitative analysis is undertaken. One common approach to estimate randoms is the so-called singles rate method (SR) widely used because of its good statistical properties. SR is based on the measurement of the singles rate in each detector element. However, recent studies suggest that SR systematically overestimates the correct random rate. This overestimation can be particularly marked for low energy thresholds, below 250 keV used in some applications and could entail a significant image degradation. In this work, we investigate the performance of SR as a function of the activity, geometry of the source and energy acceptance window used. We also investigate the performance of an alternative method, which we call 'singles trues' (ST) that improves SR by properly modeling the presence of true coincidences in the sample. Nevertheless, in any real data acquisition the knowledge of which singles are members of a true coincidence is lost. Therefore, we propose an iterative method, STi, that provides an estimation based on ST but which only requires the knowledge of measurable quantities: prompts and singles. Due to inter-crystal scatter, for wide energy windows ST only partially corrects SR overestimations. While SR deviations are in the range 86-300% (depending on the source geometry), the ST deviations are systematically smaller and contained in the range 4-60%. STi fails to reproduce the ST results, although for not too high activities the deviation with respect to ST is only a few percent. For conventional energy windows, i.e. those without inter-crystal scatter, the ST method corrects the SR overestimations, and deviations from

Investigation of time-of-flight benefits in an LYSO-based PET/CT scanner: A Monte Carlo study using GATE

International Nuclear Information System (INIS)

Geramifar, P.; Ay, M.R.; Shamsaie Zafarghandi, M.; Sarkar, S.; Loudos, G.; Rahmim, A.

2011-01-01

The advent of fast scintillators yielding great light yield and/or stopping power, along with advances in photomultiplier tubes and electronics, have rekindled interest in time-of-flight (TOF) PET. Because the potential performance improvements offered by TOF PET are substantial, efforts to improve PET timing should prove very fruitful. In this study, we performed Monte Carlo simulations to explore what gains in PET performance could be achieved if the coincidence resolving time (CRT) in the LYSO-based PET component of Discovery RX PET/CT scanner were improved. For this purpose, the GATE Monte Carlo package was utilized, providing the ability to model and characterize various physical phenomena in PET imaging. For the present investigation, count rate performance and signal to noise ratio (SNR) values in different activity concentrations were simulated for different coincidence timing windows of 4, 5.85, 6, 6.5, 8, 10 and 12 ns and with different CRTs of 100-900 ps FWHM involving 50 ps FWHM increments using the NEMA scatter phantom. Strong evidence supporting robustness of the simulations was found as observed in the good agreement between measured and simulated data for the cases of estimating axial sensitivity, axial and transaxial detection position, gamma non-collinearity angle distribution and positron annihilation distance. In the non-TOF context, the results show that the random event rate can be reduced by using narrower coincidence timing window widths, demonstrating considerable enhancements in the peak noise equivalent count rate (NECR) performance. The peak NECR had increased by ∼50% when utilizing the coincidence window width of 4 ns. At the same time, utilization of TOF information resulted in improved NECR and SNR with the dramatic reduction of random coincidences as a function of CRT. For example, with CRT of 500 ps FWHM, a factor of 2.3 reduction in random rates, factor of 1.5 increase in NECR and factor of 2.1 improvement in SNR is achievable

Investigation of time-of-flight benefits in an LYSO-based PET/CT scanner: A Monte Carlo study using GATE

Energy Technology Data Exchange (ETDEWEB)

Geramifar, P. [Faculty of Physics and Nuclear Engineering, Amir Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Ay, M.R., E-mail: mohammadreza_ay@tums.ac.ir [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shamsaie Zafarghandi, M. [Faculty of Physics and Nuclear Engineering, Amir Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Sarkar, S. [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Loudos, G. [Department of Medical Instruments Technology, Technological Educational Institute, Athens (Greece); Rahmim, A. [Department of Radiology, School of Medicine, Johns Hopkins University, Baltimore (United States); Department of Electrical and Computer Engineering, School of Engineering, Johns Hopkins University, Baltimore (United States)

2011-06-11

The advent of fast scintillators yielding great light yield and/or stopping power, along with advances in photomultiplier tubes and electronics, have rekindled interest in time-of-flight (TOF) PET. Because the potential performance improvements offered by TOF PET are substantial, efforts to improve PET timing should prove very fruitful. In this study, we performed Monte Carlo simulations to explore what gains in PET performance could be achieved if the coincidence resolving time (CRT) in the LYSO-based PET component of Discovery RX PET/CT scanner were improved. For this purpose, the GATE Monte Carlo package was utilized, providing the ability to model and characterize various physical phenomena in PET imaging. For the present investigation, count rate performance and signal to noise ratio (SNR) values in different activity concentrations were simulated for different coincidence timing windows of 4, 5.85, 6, 6.5, 8, 10 and 12 ns and with different CRTs of 100-900 ps FWHM involving 50 ps FWHM increments using the NEMA scatter phantom. Strong evidence supporting robustness of the simulations was found as observed in the good agreement between measured and simulated data for the cases of estimating axial sensitivity, axial and transaxial detection position, gamma non-collinearity angle distribution and positron annihilation distance. In the non-TOF context, the results show that the random event rate can be reduced by using narrower coincidence timing window widths, demonstrating considerable enhancements in the peak noise equivalent count rate (NECR) performance. The peak NECR had increased by {approx}50% when utilizing the coincidence window width of 4 ns. At the same time, utilization of TOF information resulted in improved NECR and SNR with the dramatic reduction of random coincidences as a function of CRT. For example, with CRT of 500 ps FWHM, a factor of 2.3 reduction in random rates, factor of 1.5 increase in NECR and factor of 2.1 improvement in SNR is

Evaluation of 68Ga-DOTATOC PET/MRI for whole-body staging of neuroendocrine tumours in comparison with 68Ga-DOTATOC PET/CT

International Nuclear Information System (INIS)

Sawicki, Lino M.; Deuschl, Cornelius; Beiderwellen, Karsten; Forsting, Michael; Umutlu, Lale; Ruhlmann, Verena; Poeppel, Thorsten D.; Bockisch, Andreas; Herrmann, Ken; Heusch, Philipp; Antoch, Gerald; Lahner, Harald; Fuehrer, Dagmar

2017-01-01

To compare the diagnostic performance of 68 Ga-DOTATOC PET/MRI and 68 Ga-DOTATOC PET/CT in the whole-body staging of patients with neuroendocrine tumours (NET). Thirty patients with histopathologically confirmed NET underwent PET/CT and PET/MRI in a single-injection protocol. PET/CT and PET/MRI scans were prospectively evaluated with regard to lesion count, localization, nature (NET/non-NET), and conspicuity (four-point scale). Histopathology and follow-up imaging served as the reference standards. The proportions of NET and non-NET lesions rated correctly were compared using McNemar's chi-squared test. The Wilcoxon test was used to assess differences in SUVmax and lesion conspicuity. The correlation between the SUVmax for the same lesions from each modality was analysed using Pearson's correlation coefficient (r). According to the reference standard, there were 197 lesions (142 NET, 55 non-NET). Lesion-based analysis showed a higher proportion of correctly rated NET lesions on PET/MRI than on PET/CT (90.8% vs. 86.7%, p = 0.031), whereas on PET/CT there was a higher proportion of correctly rated non-NET lesions (94.5% vs. 83.6%, p = 0.031). SUVmax was strongly correlated (r = 0.86; p < 0.001) and did not differ significantly (p = 0.35) between the modalities. Overall conspicuity and NET lesion conspicuity were higher on PET/MRI (both p < 0.01). Ga-DOTATOC PET/MRI yielded a higher proportion of correctly rated NET lesions and should be regarded as a valuable alternative to 68 Ga-DOTATOC PET/CT in whole-body staging of NET patients. (orig.)

Impact of F.D.G.-PET on radiation therapy: economic results of a STIC study

International Nuclear Information System (INIS)

Remonnay, R.; Morelle, M.; Pommier, P.; Carrere, M.O.; Giammaril, F.; Pommier, P.

2009-01-01

The aim of this study is to assess the effects of Positron Emission Tomography (PET) associated with computed tomography (CT) on resource allocation (costs and savings) of the following treatment in radiotherapy for non small cell lung cancers (N.S.C.L.C.) and Hodgkin's diseases. A national prospective study was conducted in nine hospitals. Two treatment decisions made on the basis of CT only or on PET associated with, were compared in a before-after design. The direct medical cost of using PET was assessed by micro-costing. The costs of new exams and the costs and savings associated with changes in the chosen treatment were calculated on the basis of reimbursement rates. The economic study was conducted over 2 years and included 209 patients (97 patients with Hodgkin's disease and 112 with N.S.C.L.C.). The mean cost of using PET, corresponding to an extra cost, was approximately 800 Euros (50% for the radionuclide F.D.G.). Radiotherapy treatments were modified for only 10% of patients with Hodgkin's disease with a minor impact on treatment costs versus 40% of patients with lung cancer with a reduction in mean treatment cost of more than 500 Euros. (authors)

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

International Nuclear Information System (INIS)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah

2014-01-01

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after 18 F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast-enhanced PET

Evaluation of Dixon Sequence on Hybrid PET/MR Compared with Contrast-Enhanced PET/CT for PET-Positive Lesions

Energy Technology Data Exchange (ETDEWEB)

Jeong, Ju Hye; Cho, Ihn Ho; Kong, Eun Jung; Chun, Kyung Ah [Yeungnam Univ. Hospital, Daegu (Korea, Republic of)

2014-03-15

Hybrid positron emission tomography and magnetic resonance (PET/MR) imaging performs a two-point Dixon MR sequence for attenuation correction. However, MR data in hybrid PET/MR should provide anatomic and morphologic information as well as an attenuation map. We evaluated the Dixon sequence of hybrid PET/MR for anatomic correlation of PET-positive lesions compared with contrast-enhanced PET/computed tomography (CT) in patients with oncologic diseases. Twelve patients underwent a single injection, dual imaging protocol. PET/CT was performed with an intravenous contrast agent (85±13 min after {sup 18}F-FDG injection of 403± 45 MBq) and then (125±19 min after injection) PET/MR was performed. Attenuation correction and anatomic allocation of PET were performed using contrast-enhanced CT for PET/CT and Dixon MR sequence for hybrid PET/MR. The Dixon MR sequence and contrast-enhanced CT were compared for anatomic correlation of PET-positive lesions (scoring scale ranging from 0 to 3 for visual ratings). Additionally, standardized uptake values (SUVs) for the detected lesions were assessed for quantitative comparison. Both hybrid PET/MR and contrast-enhanced PET/CT identified 55 lesions with increased FDG uptake in ten patients. In total, 28 lymph nodes, 11 bone lesions, 3 dermal nodules, 3 pleural thickening lesions, 2 thyroid nodules, 1 pancreas, 1 liver, 1 ovary, 1 uterus, 1 breast, 1 soft tissue and 2 lung lesions were present. The best performance was observed for anatomic correlation of PET findings by the contrast-enhanced CT scans (contrast-enhanced CT, 2.64± 0.70; in-phase, 1.29±1.01; opposed-phase, 1.29±1.15; water-weighted, 1.71±1.07; fat weighted, 0.56±1.03). A significant difference was observed between the scores obtained from the contrast-enhanced CT and all four coregistered Dixon MR images. Quantitative evaluation revealed a high correlation between the SUVs measured with hybrid PET/MR (SUVmean, 2.63±1.62; SUVmax, 4.30±2.88) and contrast

Detection of Cancer with PET and PET/CT in Asymptomatic Volunteers

International Nuclear Information System (INIS)

Chung, Ji In; Choi, Joon Young; Lee, Kyung Han; Kim, Byung Tae; Choi, Yoon Ho; Cho, Han Byoul; Shim, Jae Yong

2009-01-01

We retrospectively investigated the diagnostic performance of 18 F-fluorodeoxyglucose positron emission tomography (PET) and PET/CT for cancer detection in asymptomatic health-check examinees. This study consisted of 5091 PET or PET/CT conducted as part of annual health examination at one hospital from March 1998 to February 2008. To find the incidence of cancers, medical records of the subjects were thoroughly reviewed for a follow-up period of one year. The patterns of formal readings of PET and PET/CT were analyzed to assess the sensitivity and specificity for cancer detection. The histopathology and stage of the cancers were evaluated in relation to the results of PET. Eighty-six cancers (1.7%) were diagnosed within one year after PET or PET/CT. When PET and PET/CT results were combined, the sensitivity was 48.8% and specificity was 81.1% for cancer detection. PET only had a sensitivity of 46.2% and a specificity of 81.4%, and PET/CT only had a sensitivity of 75.0% and a specificity of 78.5% respectively. There were no significant differences in cancer site, stage and histopathology between PET positive and PET negative cancers. In 19.3% of formal readings of PET and PET/CT, further evaluation to exclude malignancy or significant disease was recommended. Head and neck area and upper gastrointestinal tract were commonly recommended sites for further evaluation. PET and PET/CT showed moderate performance for detecting cancers in asymptomatic adults in this study. More experience and further investigation are needed to overcome limitations of PET and PET/CT for cancer screening

MR-compatibility assessment of MADPET4: a study of interferences between an SiPM-based PET insert and a 7 T MRI system

Science.gov (United States)

Omidvari, Negar; Topping, Geoffrey; Cabello, Jorge; Paul, Stephan; Schwaiger, Markus; Ziegler, Sibylle I.

2018-05-01

Compromises in the design of a positron emission tomography (PET) insert for a magnetic resonance imaging (MRI) system should minimize the deterioration of image quality in both modalities, particularly when simultaneous demanding acquisitions are performed. In this work, the advantages of using individually read-out crystals with high-gain silicon photomultipliers (SiPMs) were studied with a small animal PET insert for a 7 T MRI system, in which the SiPM charge was transferred to outside the MRI scanner using coaxial cables. The interferences between the two systems were studied with three radio-frequency (RF) coil configurations. The effects of PET on the static magnetic field, flip angle distribution, RF noise, and image quality of various MRI sequences (gradient echo, spin echo, and echo planar imaging (EPI) at 1H frequency, and chemical shift imaging at 13C frequency) were investigated. The effects of fast-switching gradient fields and RF pulses on PET count rate were studied, while the PET insert and the readout electronics were not shielded. Operating the insert inside a 1H volume coil, used for RF transmission and reception, limited the MRI to T1-weighted imaging, due to coil detuning and RF attenuation, and resulted in significant PET count loss. Using a surface receive coil allowed all tested MR sequences to be used with the insert, with 45–59% signal-to-noise ratio (SNR) degradation, compared to without PET. With a 1H/13C volume coil inside the insert and shielded by a copper tube, the SNR degradation was limited to 23–30% with all tested sequences. The insert did not introduce any discernible distortions into images of two tested EPI sequences. Use of truncated sinc shaped RF excitation pulses and gradient field switching had negligible effects on PET count rate. However, PET count rate was substantially affected by high-power RF block pulses and temperature variations due to high gradient duty cycles.

PSA-stratified detection rates for [68Ga]THP-PSMA, a novel probe for rapid kit-based 68Ga-labeling and PET imaging, in patients with biochemical recurrence after primary therapy for prostate cancer.

Science.gov (United States)

Derlin, Thorsten; Schmuck, Sebastian; Juhl, Cathleen; Zörgiebel, Johanna; Schneefeld, Sophie M; Walte, Almut C A; Hueper, Katja; von Klot, Christoph A; Henkenberens, Christoph; Christiansen, Hans; Thackeray, James T; Ross, Tobias L; Bengel, Frank M

2018-06-01

[ 68 Ga]Tris(hydroxypyridinone)(THP)-PSMA is a novel radiopharmaceutical for one-step kit-based radiolabelling, based on direct chelation of 68 Ga 3+ at low concentration, room temperature and over a wide pH range, using direct elution from a 68 Ge/ 68 Ga-generator. We evaluated the clinical detection rates of [ 68 Ga]THP-PSMA PET/CT in patients with biochemically recurrent prostate cancer after prostatectomy. Consecutive patients (n=99) referred for evaluation of biochemical relapse of prostate cancer by [ 68 Ga]THP-PSMA PET/CT were analyzed retrospectively. Patients underwent a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified cohorts of positive PET/CT results, standardized uptake values (SUVs) and target-to-background ratios (TBRs) were analyzed, and compared between standard and delayed imaging. At least one lesion suggestive of recurrent or metastatic prostate cancer was identified on PET images in 52 patients (52.5%). Detection rates of [ 68 Ga]THP-PSMA PET/CT increased with increasing PSA level: 94.1% for a PSA value of ≥10 ng/mL, 77.3% for a PSA value of 2 to PSA value of 1 to PSA value of 0.5 to PSA value of >0.2 to PSA value of 0.01 to 0.2 ng/mL. [ 68 Ga]THP-PSMA uptake (SUVs) in metastases decreased over time, whereas TBRs improved. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 2% of [ 68 Ga]THP-PSMA PET/CT scans. Detection rate was higher in patients with a Gleason score ≥8 (P=0.02) and in patients receiving androgen deprivation therapy (P=0.003). In this study, [ 68 Ga]THP-PSMA PET/CT showed suitable detection rates in patients with biochemical recurrence of prostate cancer and PSA levels ≥ 2 ng /mL. Detections rates were lower than in previous studies evaluating other PSMA ligands, though prospective direct radiotracer comparison studies are mandatory particularly in patients with low PSA levels to evaluate the relative performance of different PSMA ligands.

Comparison of the diagnostic accuracy of PET/MRI to PET/CT-acquired FDG brain exams for seizure focus detection: a prospective study

Energy Technology Data Exchange (ETDEWEB)

Paldino, Michael J.; Jones, Jeremy Y.; Mahmood, Nadia; Sher, Andrew; Hayatghaibi, Shireen; Seghers, Victor [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Yang, Erica [SimonMed Imaging, Department of Radiology, Scottsdale, AZ (United States); Zhang, Wei [Texas Children' s Hospital, Outcomes and Impact Service, Houston, TX (United States); Krishnamurthy, Ramkumar [Nationwide Children' s Hospital, Department of Radiology, Columbus, OH (United States)

2017-10-15

There is great interest in positron emission tomography (PET)/magnetic resonance (MR) as a clinical tool due to its capacity to provide diverse diagnostic information in a single exam. The goal of this exam is to compare the diagnostic accuracy of PET/MR-acquired [F-18]2-fluoro-2-deoxyglucose (FDG) brain exams to that of PET/CT with respect to identifying seizure foci in children with localization-related epilepsy. Institutional Review Board approval and informed consent were obtained for this Health Insurance Portability and Accountability Act-compliant, prospective study. All patients referred for clinical FDG-PET/CT exams of the brain at our institution for a diagnosis of localization-related epilepsy were prospectively recruited to undergo an additional FDG-PET acquisition on a tandem PET/MR system. Attenuation-corrected FDG images acquired at PET/MR and PET/CT were interpreted independently by five expert readers. Readers were blinded to the scanner used for acquisition and attenuation correction as well as all other clinical and imaging data. A Likert scale scoring system (1-5) was used to assess image quality. The locale of seizure origin determined at multidisciplinary epilepsy surgery work rounds was considered the reference standard. Non-inferiority testing for paired data was used to compare the diagnostic accuracy of PET/MR to that of PET/CT. The final study population comprised 35 patients referred for a diagnosis of localization-related epilepsy (age range: 2-19 years; median: 11 years; 21 males, 14 females). Image quality did not differ significantly between the two modalities. The accuracy of PET/MR was not inferior to that of PET/CT for localization of a seizure focus (P=0.017). The diagnostic accuracy of FDG-PET images acquired on a PET/MR scanner and generated using MR-based attenuation correction was not inferior to that of PET images processed by traditional CT-based correction. (orig.)

Comparison of the diagnostic accuracy of PET/MRI to PET/CT-acquired FDG brain exams for seizure focus detection: a prospective study

International Nuclear Information System (INIS)

Paldino, Michael J.; Jones, Jeremy Y.; Mahmood, Nadia; Sher, Andrew; Hayatghaibi, Shireen; Seghers, Victor; Yang, Erica; Zhang, Wei; Krishnamurthy, Ramkumar

2017-01-01

There is great interest in positron emission tomography (PET)/magnetic resonance (MR) as a clinical tool due to its capacity to provide diverse diagnostic information in a single exam. The goal of this exam is to compare the diagnostic accuracy of PET/MR-acquired [F-18]2-fluoro-2-deoxyglucose (FDG) brain exams to that of PET/CT with respect to identifying seizure foci in children with localization-related epilepsy. Institutional Review Board approval and informed consent were obtained for this Health Insurance Portability and Accountability Act-compliant, prospective study. All patients referred for clinical FDG-PET/CT exams of the brain at our institution for a diagnosis of localization-related epilepsy were prospectively recruited to undergo an additional FDG-PET acquisition on a tandem PET/MR system. Attenuation-corrected FDG images acquired at PET/MR and PET/CT were interpreted independently by five expert readers. Readers were blinded to the scanner used for acquisition and attenuation correction as well as all other clinical and imaging data. A Likert scale scoring system (1-5) was used to assess image quality. The locale of seizure origin determined at multidisciplinary epilepsy surgery work rounds was considered the reference standard. Non-inferiority testing for paired data was used to compare the diagnostic accuracy of PET/MR to that of PET/CT. The final study population comprised 35 patients referred for a diagnosis of localization-related epilepsy (age range: 2-19 years; median: 11 years; 21 males, 14 females). Image quality did not differ significantly between the two modalities. The accuracy of PET/MR was not inferior to that of PET/CT for localization of a seizure focus (P=0.017). The diagnostic accuracy of FDG-PET images acquired on a PET/MR scanner and generated using MR-based attenuation correction was not inferior to that of PET images processed by traditional CT-based correction. (orig.)

Evaluation of attenuation correction in cardiac PET using PET/MR.

Science.gov (United States)

Lau, Jeffrey M C; Laforest, R; Sotoudeh, H; Nie, X; Sharma, S; McConathy, J; Novak, E; Priatna, A; Gropler, R J; Woodard, P K

2017-06-01

Simultaneous acquisition Positron emission tomography/magnetic resonance (PET/MR) is a new technology that has potential as a tool both in research and clinical diagnosis. However, cardiac PET acquisition has not yet been validated using MR imaging for attenuation correction (AC). The goal of this study is to evaluate the feasibility of PET imaging using a standard 2-point Dixon volume interpolated breathhold examination (VIBE) MR sequence for AC. Evaluation was performed in both phantom and patient data. A chest phantom containing heart, lungs, and a lesion insert was scanned by both PET/MR and PET/CT. In addition, 30 patients underwent whole-body 18 F-fluorodeoxyglucose PET/CT followed by simultaneous cardiac PET/MR. Phantom study showed 3% reduction of activity values in the myocardium due to the non-inclusion of the phased array coil in the AC. In patient scans, average standardized uptake values (SUVs) obtained by PET/CT and PET/MR showed no significant difference (n = 30, 4.6 ± 3.5 vs 4.7 ± 2.8, P = 0.47). There was excellent per patient correlation between the values acquired by PET/CT and PET/MR (R 2  = 0.97). Myocardial SUVs PET imaging using MR for AC shows excellent correlation with myocardial SUVs obtained by standard PET/CT imaging. The 2-point Dixon VIBE MR technique can be used for AC in simultaneous PET/MR data acquisition.

PET studies in Alzheimer disease and other degenerative dementias

International Nuclear Information System (INIS)

Jeong, Yong; Na, Duk L.

2003-01-01

Neurodegenerative disorders cause a variety of dementia including Alzheimer disease, frontotemporal dementia, dementia with Lewy bodies, corticobasal degeneration, progressive supranuclear palsy, and Huntington's disease. PET scan is useful for early detection and differential diagnosis of theses dementing disorders. Also, it provides valuable information about clinico-anatomical correlation, allowing better understanding of function of brain. Here we discuss recent achievements PET studies regarding these dementing disorders. Future progress in PET technology, new tracers, and image analysis will play an important role in further clarifying the disease pathophysiology and brain functions

A Study on Mental Health Status and Personality Traits of Pet Owners

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H Choobineh

2007-07-01

Full Text Available Introduction & Objective: Many Iranian families manage to keep pets at home. Examining psychological consequences and personality traits of pet owners is important. The aim of this study was to examine mental health status and personality traits of pet owners. Materials & Methods: In this descriptive study, 612 pet owners (143 cat owners, 162 dog owners, 155 bird owners and 152 other pet owners were asked to complete General Health Questionnaire (GHQ and IPIP Personality Scale from January to December 2006. Results: Bird owners had the highest (234 cases (38.3% and other pet owners had the lowest (129 cases (42.3% mental health problems. In general, 188 cases (30.7% of all groups had mental health problems. 122 cases (20% of them had somatic compliance, 182 cases (29.7% had anxiety, 149 cases (24.3% had social dysfunction and 84 cases (13.7% had depression. Bird owners had significant high level of social dysfunction than other pet owners. With respect to personality traits, dog owners had low level of agreeableness and openness to experience than other groups. Other pet owners had high level of emotional stability than other groups. Conclusion: Contrary to other countries, it seems that having a pet in home enhances the probability of mental disorders in Iran. It is possible that lower mental health persons were keeping pets in Iran. In personality perspectives, dog owners are more disagreeable people and other pet owners are more emotionally stable ones.

Studies of a Next-Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System.

Science.gov (United States)

Hsu, David F C; Ilan, Ezgi; Peterson, William T; Uribe, Jorge; Lubberink, Mark; Levin, Craig S

2017-09-01

This article presents system performance studies for the Discovery MI PET/CT system, a new time-of-flight system based on silicon photomultipliers. System performance and clinical imaging were compared between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms. Methods: Spatial resolution, sensitivity, noise-equivalent counting rate, scatter fraction, counting rate accuracy, and image quality were characterized with the National Electrical Manufacturers Association NU-2 2012 standards. Energy resolution and coincidence time resolution were measured. Tests were conducted independently on two Discovery MI scanners installed at Stanford University and Uppsala University, and the results were averaged. Back-to-back patient scans were also performed between the Discovery MI, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed using both ordered-subset expectation maximization and Q.Clear (block-sequential regularized expectation maximization with point-spread function modeling) and were examined qualitatively. Results: The averaged full widths at half maximum (FWHMs) of the radial/tangential/axial spatial resolution reconstructed with filtered backprojection at 1, 10, and 20 cm from the system center were, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity was 13.7 cps/kBq at the center of the field of view. The averaged peak noise-equivalent counting rate was 193.4 kcps at 21.9 kBq/mL, with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image-quality phantom were 53.7, 64.0, 73.1, 82.7, 86.8, and 90.7 for the 10-, 13-, 17-, 22-, 28-, and 37-mm-diameter spheres, respectively. The average photopeak energy resolution was 9.40% FWHM, and the average coincidence time resolution was 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrated the high

PET/CT-guided interventional procedures: rationale, justification, initial study, and research plan

Energy Technology Data Exchange (ETDEWEB)

Wong, K.; Rahill, J.; Cleary, K. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Petrillo, S.; Earl-Graef, D. [Dept. of Radiology, Georgetown Univ. Hospital, MedStar Health, Washington, DC (United States); Banovac, F.; Levy, E. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Dept. of Radiology, Georgetown Univ. Hospital, MedStar Health, Washington, DC (United States); Shekhar, R. [Dept. of Radiology, Univ. of Maryland Medical Center, Baltimore, MD (United States)

2007-06-15

Positron-emission tomography (PET) and PET/CT (computed tomography) are becoming increasingly important for diagnosis and treatment of cancer. Clinically relevant changes can sometimes be seen on PET that are not seen on other imaging modalities. However, PET is not suitable for guiding biopsy as the images are not obtained in real-time. Therefore, our research group has begun developing a concept for PET/CT-guided interventional procedures. This paper presents the rationale for this concept, outlines our research plan, and includes an initial study to evaluate the relative sensitivity of CT and PET/CT in detecting suspicious lesions. (orig.)

Automatic extraction of forward stroke volume using dynamic PET/CT

DEFF Research Database (Denmark)

Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik Stubkjær

2015-01-01

Background The aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners. Methods 35 subjects underwent...... a dynamic 11 C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic 15 O-water PET and 11 C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically...... from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase...

Preliminary results of a prototype C-shaped PET designed for an in-beam PET system

International Nuclear Information System (INIS)

Kim, Hyun-Il; Chung, Yong Hyun; Lee, Kisung; Kim, Kyeong Min; Kim, Yongkwon; Joung, Jinhun

2016-01-01

Positron emission tomography (PET) can be utilized in particle beam therapy to verify the dose distribution of the target volume as well as the accuracy of the treatment. We present an in-beam PET scanner that can be integrated into a particle beam therapy system. The proposed PET scanner consisted of 14 detector modules arranged in a C-shape to avoid blockage of the particle beam line by the detector modules. Each detector module was composed of a 9×9 array of 4.0 mm×4.0 mm×20.0 mm LYSO crystals optically coupled to four 29-mm-diameter PMTs using the photomultiplier-quadrant-sharing (PQS) technique. In this study, a Geant4 Application for Tomographic Emission (GATE) simulation study was conducted to design a C-shaped PET scanner and then experimental evaluation of the proposed design was performed. The spatial resolution and sensitivity were measured according to NEMA NU2-2007 standards and were 6.1 mm and 5.61 cps/kBq, respectively, which is in good agreement with our simulation, with an error rate of 12.0%. Taken together, our results demonstrate the feasibility of the proposed C-shaped in-beam PET system, which we expect will be useful for measuring dose distribution in particle therapy.

PET/CT in patients with hepatocellular carcinoma using [{sup 18}F]fluorocholine: preliminary comparison with [{sup 18}F]FDG PET/CT

Energy Technology Data Exchange (ETDEWEB)

Talbot, Jean-Noel; Gutman, Fabrice; Kerrou, Khaldoun; Grahek, Dany; Montravers, Francoise [Hopital Tenon, AP-HP, et Universite Pierre et Marie Curie, Department of Nuclear Medicine, Paris (France); Fartoux, Laetitia; Poupon, Raoul; Rosmorduc, Olivier [Hopital Saint-Antoine, AP-HP, et Universite Pierre et Marie Curie, Department of Hepatology, Paris (France); Grange, Jean-Didier [Hopital Tenon, AP-HP, et Universite Pierre et Marie Curie, Department of Hepatology, Paris (France); Ganne, Nathalie [Hopital Jean Verdier, AP-HP, Department of Hepatology, Bondy (France)

2006-11-15

The diagnostic accuracy of [{sup 18}F]fluorodeoxyglucose (FDG) PET is insufficient to characterise hepatocellular carcinoma (HCC) in liver masses and to diagnose all cases of recurrent HCC. HCC has been reported to take up [{sup 11}C]acetate, but routine use of this tracer is difficult. Choline is another tracer of lipid metabolism, present in large amounts in HCC. In a proof-of-concept study, we evaluated [{sup 18}F]fluorocholine (FCH) uptake by HCC and compared FCH PET/CT with FDG PET/CT. Twelve patients with newly diagnosed (n=8) or recurrent HCC (n=4) were prospectively enrolled. HCC was assessed by histology in eight cases and by American Association for the Study of Liver Diseases (AASLD) criteria in four cases. All patients underwent whole-body PET/CT 10 min after injection of 4 MBq/kg FCH. Within 1 week, 9 of the 12 patients also underwent whole-body FDG PET/CT 1 h after injection of 5 MBq/kg FDG. The per-patient analysis showed a detection rate of 12/12 using FCH PET/CT for both newly diagnosed and recurrent HCC. The median signal to noise ratio was 1.5{+-}0.38. There was a trend towards a higher FCH SUV{sub max} in well-differentiated HCC (15.6{+-}7.9 vs 11.9{+-}0.9, NS). Of the nine patients who underwent FCH and FDG PET/CT, all nine were positive with FCH whereas only five were positive with FDG. FCH provides a high detection rate for HCC, making it potentially useful in the initial evaluation of HCC or in the detection of recurrent disease. The favourable result of this proof-of-concept study opens the way to a phase III prospective study. (orig.)

Giant-cell arteritis. Concordance study between aortic CT angiography and FDG-PET/CT in detection of large-vessel involvement

International Nuclear Information System (INIS)

Boysson, Hubert de; Dumont, Anael; Boutemy, Jonathan; Maigne, Gwenola; Martin Silva, Nicolas; Sultan, Audrey; Bienvenu, Boris; Aouba, Achille; Liozon, Eric; Ly, Kim Heang; Lambert, Marc; Aide, Nicolas; Manrique, Alain

2017-01-01

The purpose of our study was to assess the concordance of aortic CT angiography (CTA) and FDG-PET/CT in the detection of large-vessel involvement at diagnosis in patients with giant-cell arteritis (GCA). We created a multicenter cohort of patients with GCA diagnosed between 2010 and 2015, and who underwent both FDG-PET/CT and aortic CTA before or in the first ten days following treatment introduction. Eight vascular segments were studied on each procedure. We calculated concordance between both imaging techniques in a per-patient and a per-segment analysis, using Cohen's kappa concordance index. We included 28 patients (21/7 women/men, median age 67 [56-82]). Nineteen patients had large-vessel involvement on PET/CT and 18 of these patients also presented positive findings on CTA. In a per-segment analysis, a median of 5 [1-7] and 3 [1-6] vascular territories were involved on positive PET/CT and CTA, respectively (p = 0.03). In qualitative analysis, i.e., positivity of the procedure suggesting a large-vessel involvement, the concordance rate between both procedures was 0.85 [0.64-1]. In quantitative analysis, i.e., per-segment analysis in both procedures, the global concordance rate was 0.64 [0.54-0.75]. Using FDG-PET/CT as a reference, CTA showed excellent sensitivity (95%) and specificity (100%) in a per-patient analysis. In a per-segment analysis, sensitivity and specificity were 61% and 97.9%, respectively. CTA and FDG-PET/CT were both able to detect large-vessel involvement in GCA with comparable results in a per-patient analysis. However, PET/CT showed higher performance in a per-segment analysis, especially in the detection of inflammation of the aorta's branches. (orig.)

Giant-cell arteritis. Concordance study between aortic CT angiography and FDG-PET/CT in detection of large-vessel involvement

Energy Technology Data Exchange (ETDEWEB)

Boysson, Hubert de; Dumont, Anael; Boutemy, Jonathan; Maigne, Gwenola; Martin Silva, Nicolas; Sultan, Audrey; Bienvenu, Boris; Aouba, Achille [Caen University Hospital, Department of Internal Medicine, Caen (France); Liozon, Eric; Ly, Kim Heang [Limoges University Hospital, Department of Internal Medicine, Limoges (France); Lambert, Marc [Lille University Hospital, Department of Internal Medicine, Lille (France); Aide, Nicolas [Caen University Hospital, Department of Nuclear Medicine, Caen (France); INSERM U1086 ' ' ANTICIPE' ' , Francois Baclesse Cancer Centre, Caen (France); Manrique, Alain [Caen University Hospital, Department of Nuclear Medicine, Caen (France); Normandy University, Caen (France)

2017-12-15

The purpose of our study was to assess the concordance of aortic CT angiography (CTA) and FDG-PET/CT in the detection of large-vessel involvement at diagnosis in patients with giant-cell arteritis (GCA). We created a multicenter cohort of patients with GCA diagnosed between 2010 and 2015, and who underwent both FDG-PET/CT and aortic CTA before or in the first ten days following treatment introduction. Eight vascular segments were studied on each procedure. We calculated concordance between both imaging techniques in a per-patient and a per-segment analysis, using Cohen's kappa concordance index. We included 28 patients (21/7 women/men, median age 67 [56-82]). Nineteen patients had large-vessel involvement on PET/CT and 18 of these patients also presented positive findings on CTA. In a per-segment analysis, a median of 5 [1-7] and 3 [1-6] vascular territories were involved on positive PET/CT and CTA, respectively (p = 0.03). In qualitative analysis, i.e., positivity of the procedure suggesting a large-vessel involvement, the concordance rate between both procedures was 0.85 [0.64-1]. In quantitative analysis, i.e., per-segment analysis in both procedures, the global concordance rate was 0.64 [0.54-0.75]. Using FDG-PET/CT as a reference, CTA showed excellent sensitivity (95%) and specificity (100%) in a per-patient analysis. In a per-segment analysis, sensitivity and specificity were 61% and 97.9%, respectively. CTA and FDG-PET/CT were both able to detect large-vessel involvement in GCA with comparable results in a per-patient analysis. However, PET/CT showed higher performance in a per-segment analysis, especially in the detection of inflammation of the aorta's branches. (orig.)

PET AND SPECT STUDIES IN CHILDREN WITH HEMISPHERIC LOW-GRADE GLIOMAS

Science.gov (United States)

Juhász, Csaba; Bosnyák, Edit

2016-01-01

Molecular imaging is playing an increasing role in the pre-treatment evaluation of low-grade gliomas. While glucose positron emission tomography (PET) can be helpful to differentiate low-grade from high-grade tumors, PET imaging with amino acid radiotracers has several advantages, such as better differentiation between tumors and non-tumorous lesions, optimized biopsy targeting and improved detection of tumor recurrence. This review provides a brief overview of single photon emission computed tomography (SPECT) studies followed by a more detailed review of clinical applications of glucose and amino acid PET imaging in low-grade hemispheric gliomas. We discuss key differences in the performance of the most commonly utilized PET radiotracers and highlight the advantage of PET/MRI fusion to obtain optimal information about tumor extent, heterogeneity and metabolism. Recent data also suggest that simultaneous acquisition of PET/MR images and the combination of advanced MRI techniques with quantitative PET can further improve the pre- and post-treatment evaluation of pediatric brain tumors. PMID:27659825

Serotonin synthesis studied with positron emission tomography, (PET)

DEFF Research Database (Denmark)

Honoré, Per Gustaf Hartvig; Lundquist, Pinelopi

-L-(beta-11C tryptophan) (5HTP) quantifies the activity of amino acid decarboxylase in the conversion to 5HT. On the other hand, alpha-methyl-tryptophan (AMT) measures the conversion to the corresponding 5-hydroxytryptophan analogue. The irreversible binding of the PET probe 5HTP in the monkey brain was lower...... evaluations of neuroendocrine tumours. Though, a few studies using 5HT have been conducted on CNS disorders. AMT-PET studies have mainly been confined to brain diseases causing various degree of neurodegeneration....

Carbon-11 tyrosine PET for visualization and protein synthesis rate assessment of laryngeal and hypopharyngeal carcinomas

Energy Technology Data Exchange (ETDEWEB)

Boer, Jurjan R. de; Laan, Bernard F.A.M. van der; Albers, Frans W.J. [Department of Otorhinolaryngology and Head and Neck Surgery, Groningen University Hospital, Hanzeplein 1, 9700 RB Groningen (Netherlands); Pruim, Jan; Que, Tjin H.; Willemsen, Antoon T.M.; Vaalburg, Willem [PET Center of Groningen University Hospital, Groningen (Netherlands); Burlage, Fred [Department of Radiotherapy, Groningen University Hospital, Groningen (Netherlands); Krikke, Allard [Department of Radiology, Groningen University Hospital, Groningen (Netherlands); Tiebosch, Anton T.M.G. [Department of Pathology, Groningen University Hospital, Groningen (Netherlands)

2002-09-01

Accurate assessment of tumour extent and lymph node involvement in squamous cell carcinomas of the head and neck region is essential for therapy planning. Unfortunately, conventional diagnostic examination and imaging techniques, which monitor tumours on the basis of anatomical parameters, have drawbacks in clinical practice. The aim of this study was to investigate the feasibility of L-[1-{sup 11}C]-tyrosine (TYR) positron emission tomography (PET) for visualisation of squamous cell carcinoma of the larynx and hypopharynx and quantification of tumour activity by assessment of protein synthesis rate (PSR). Dynamic TYR PET was performed on 31 patients with T1-T4 laryngeal or hypopharyngeal carcinoma before therapy. Plasma activity of TYR, {sup 11}CO{sub 2} and {sup 11}C-protein levels were measured, and PSRs were calculated for primary malignancies. All 31 laryngeal and hypopharyngeal tumours were visualised as a hotspot (sensitivity 100%). The median PSR of the tumours (2.06 nmol ml{sup -1} min{sup -1}; range 0.72-6.96) was significantly higher (P<0.001) than that of non-tumour (background) tissue (0.51 nmol ml{sup -1} min{sup -1}; range 0.22-0.89). L-[1-{sup 11}C]-Tyrosine PET appears to be a potential method for visualisation of primary laryngeal and hypopharyngeal tumours. In vivo quantification of tumour activity by assessment of PSR is possible and may have a future role in the therapy planning and therapy evaluation of laryngeal and hypopharyngeal tumours. (orig.)

A comparative study on PET and SPECT image formation systems for a proper scanner choice in a considered PET center

International Nuclear Information System (INIS)

Santos, G.R. dos; Oliveira, A. de; Oliveira, C.L. de

2001-01-01

Full text: In the last twenty years, the conjunction of technology and research had provided exceptional conditions for improvements on the quality of life, specially on nuclear medicine. In this area, the developed technology is being applied, making available better diagnoses and therapy to a variety of diseases. Since then the short-lived radionuclides were available only in the large physics research centers. The increasing clinical applications have led to the rapid rise in the number of compact cyclotrons throughout the world. All medical cyclotrons currently are suitable for sustaining programs for PET research and clinical application. To date, up to 122 medical cyclotrons have been established worldwide, and Brazil is about to install a new dedicated cyclotron (RDS111 from CTI), to its first PET Center, in Rio de Janeiro. Also the number of scanners worldwide has increased, mainly those based on the positrons emission and annihilation. The better result gotten in the final contrast of the object imposes a comparative study and analysis of the image formation process, either in a system based on a Single Photon Emission Computerized Tomography (SPECT), as well as on Positron Emission Tomography (PET.) This comparative study should at least follow same increasing rates of the new devices with technological advances. That kind of study can be helpful on the decision of what type of scan should be the proper one, to a PET Center, on a specific region. Obviously, many other parameters are involved in that decision, and this discussion and analyses are the main subject of the present work. The objective is to make available a realistic comparative scenario. Many of the new devices have been introduced making progresses. As an example, in the new PET scanners, the reduction of examination time, and the remarkable improvement on the diagnoses based on images. As a consequence, we have a broadening on application, better performance, and making possible the

Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR.

Science.gov (United States)

Catalano, Onofrio A; Coutinho, Artur M; Sahani, Dushyant V; Vangel, Mark G; Gee, Michael S; Hahn, Peter F; Witzel, Thomas; Soricelli, Andrea; Salvatore, Marco; Catana, Ciprian; Mahmood, Umar; Rosen, Bruce R; Gervais, Debra

2017-04-01

Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer. Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test. The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02). PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

Comparison of {sup 18}F-FET PET and perfusion-weighted MRI for glioma grading. A hybrid PET/MR study

Energy Technology Data Exchange (ETDEWEB)

Verger, Antoine [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Lorraine University, Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Nancy (France); Lorraine University, IADI, INSERM, UMR 947, Nancy (France); Filss, Christian P. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Lohmann, Philipp; Stoffels, Gabriele; Rota Kops, Elena [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); Sabel, Michael [University of Duesseldorf, Department of Neurosurgery, Duesseldorf (Germany); Wittsack, Hans J. [University Duesseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Galldiks, Norbert; Fink, Gereon R. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); University of Cologne, Department of Neurology, Cologne (Germany); University of Cologne and Bonn, Center of Integrated Oncology (CIO), Bonn (Germany); Shah, Nadim J. [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Neurology, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany); Langen, Karl-Josef [Forschungszentrum Juelich, Institute of Neuroscience and Medicine (INM-3, -4), Juelich (Germany); RWTH Aachen University Hospital, Department of Nuclear Medicine, Aachen (Germany); Juelich-Aachen Research Alliance (JARA), Section JARA-Brain, Juelich (Germany)

2017-12-15

Both perfusion-weighted MR imaging (PWI) and O-(2-{sup 18}F-fluoroethyl)-L-tyrosine PET ({sup 18}F-FET) provide grading information in cerebral gliomas. The aim of this study was to compare the diagnostic value of {sup 18}F-FET PET and PWI for tumor grading in a series of patients with newly diagnosed, untreated gliomas using an integrated PET/MR scanner. Seventy-two patients with untreated gliomas [22 low-grade gliomas (LGG), and 50 high-grade gliomas (HGG)] were investigated with {sup 18}F-FET PET and PWI using a hybrid PET/MR scanner. After visual inspection of PET and PWI maps (rCBV, rCBF, MTT), volumes of interest (VOIs) with a diameter of 16 mm were centered upon the maximum of abnormality in the tumor area in each modality and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios (TBR{sub mean}, TBR{sub max}) were calculated. In addition, Time-to-Peak (TTP) and slopes of time-activity curves were calculated for {sup 18}F-FET PET. Diagnostic accuracies of {sup 18}F-FET PET and PWI for differentiating low-grade glioma (LGG) from high-grade glioma (HGG) were evaluated by receiver operating characteristic analyses (area under the curve; AUC). The diagnostic accuracy of {sup 18}F-FET PET and PWI to discriminate LGG from HGG was similar with highest AUC values for TBR{sub mean} and TBR{sub max} of {sup 18}F-FET PET uptake (0.80, 0.83) and for TBR{sub mean} and TBR{sub max} of rCBV (0.80, 0.81). In case of increased signal in the tumor area with both methods (n = 32), local hot-spots were incongruent in 25 patients (78%) with a mean distance of 10.6 ± 9.5 mm. Dynamic FET PET and combination of different parameters did not further improve diagnostic accuracy. Both {sup 18}F-FET PET and PWI discriminate LGG from HGG with similar diagnostic performance. Regional abnormalities in the tumor area are usually not congruent indicating that tumor grading by {sup 18}F-FET PET and PWI is based on different pathophysiological phenomena. (orig.)

Optimization of PET system design for lesion detection

International Nuclear Information System (INIS)

Qi, Jinyi

2000-01-01

Traditionally, the figures of merit used in designing a PET scanner are spatial resolution, noise equivalent count rate, noise equivalent sensitivity, etc. These measures, however, do not directly reflect the lesion detectability using the PET scanner. Here we propose to optimize PET scanner design directly for lesion detection. The signal-to-noise ratio (SNR) of lesion detection can be easily computed using the theoretical expressions that we have previously derived. Because no time consuming Monte Carlo simulation is needed, the theoretical expressions allow evaluation of a large range of parameters. The PET system parameters can then be chosen to achieve the maximum SNR for lesion detection. The simulation study shown in this paper was focused a single ring PET scanner without depth of interaction measurement. Randoms and scatters were also ignored

Simultaneous whole-body 18F-FDG PET-MRI in primary staging of breast cancer: A pilot study

International Nuclear Information System (INIS)

Taneja, Sangeeta; Jena, Amarnath; Goel, Reema; Sarin, Ramesh; Kaul, Sumaid

2014-01-01

= 0.303; P = 0.003). The study showed a sensitivity of 60% and 93.3% on PET and MRI respectively for detection of axillary lymph nodes with a specificity of 91% for both and a false negative rate of 6.7% on MRI and 40% on PET. Kappa co relation analysis between PET and MRI for all the lymph nodes detected revealed fair agreement by the two modalities (κ = 0.337; P = 0.000). Combined PET-MRI increased diagnostic confidence for nodal involvement (median DC 5, range 4–5; P < 0.05). Distant metastases were found in 8/36 (22%) patients at the time of diagnosis with a total of 91 metastatic lesions on PET (DC ≥ 4) and 105 on MRI (DC ≥ 4), the difference being statistically significant (P = 0.001) while Kappa co relation analysis showed significant agreement between the two modalities (κ = 0.667; P = 0.000). Overall PET-MRI led to a change in management in 12 (33.3%) patients. Conclusion: In this pilot study, simultaneous 18 F-FDG PET-MR, has been found to be useful in whole-body initial staging of breast cancer patients

Simultaneous hyperpolarized ¹³C-pyruvate MRI and ¹⁸F-FDG-PET in cancer (hyperPET)

DEFF Research Database (Denmark)

Borgwardt, Henrik Gutte; Hansen, Adam Espe; Henriksen, Sarah T.

2015-01-01

have named this concept hyper PET. Intravenous injection of the hyperpolarized (13)C-pyruvate results in an increase of (13)C-lactate, (13)C-alanine and (13)C-CO2 ((13)C-HCO3) resonance peaks relative to the tissue, disease and the metabolic state probed. Accordingly, with dynamic nuclear polarization......In this paper we demonstrate, for the first time, the feasibility of a new imaging concept - combined hyperpolarized (13)C-pyruvate magnetic resonance spectroscopic imaging (MRSI) and (18)F-FDG-PET imaging. This procedure was performed in a clinical PET/MRI scanner with a canine cancer patient. We...... (DNP) and use of (13)C-pyruvate it is now possible to directly study the Warburg Effect through the rate of conversion of (13)C-pyruvate to (13)C-lactate. In this study, we combined it with (18)F-FDG-PET that studies uptake of glucose in the cells. A canine cancer patient with a histology verified...

Temperature dependence of APD-based PET scanners

International Nuclear Information System (INIS)

Keereman, Vincent; Van Holen, Roel; Vandenberghe, Stefaan; Vanhove, Christian

2013-01-01

�C , R = −0.96) temperature changes. Count rate evaluation showed that although the total count rate is consistently higher at 21 °C than at 24 °C for different source activity concentrations, this is mainly due to an increase in scattered and random coincidences. The peak total count rate is 400 kcps at both temperatures but is reached at lower activity at 21 °C. The peak true count rate is 138 kcps (at 100 MBq) at 21 °C and 180 kcps (at 125 MBq) at 24 °C. The peak noise equivalent count rate is also lower at 21 °C (70 kcps at 70 MBq) than at 24 °C (100 kcps at 100 MBq). At realistic activity levels, the scatter fraction is lower at higher temperatures, but at the cost of a strong decrease in true count rate.Conclusions: A model was proposed for the temperature dependence of APD-based PET scanners and evaluated using the LabPET small animal PET scanner. System sensitivity and count rate performance are strongly dependent on ambient temperature while system resolution is not. The authors’ results indicate that it is important to assure stable ambient temperature to obtain reproducible results in imaging studies with APD-based PET scanners

Hybrid imaging for detection of carcinoma of unknown primary: A preliminary comparison trial of whole-body PET/MRI versus PET/CT

International Nuclear Information System (INIS)

Ruhlmann, Verena; Ruhlmann, Marcus; Bellendorf, Alexander; Grueneisen, Johannes; Sawicki, Lino M.; Grafe, Hong; Forsting, Michael; Bockisch, Andreas; Umutlu, Lale

2016-01-01

Highlights: • Both 18F-FDG PET/CT and 18F-FDG PET/MRI provide a comparable diagnostic ability for detection of primary cancer and metastases in CUP-syndrome. • Both imaging methods showed comparably high lesion conspicuity and diagnostic confidence (superior assessment of cervical lesions in PET/MRI). • PET/MRI may serve as a powerful alternative, particularly for therapy monitoring or surveillance considering the long-term cumulative dose. - Abstract: Purpose: The aim of this study is to evaluate and compare the diagnostic potential of integrated whole-body [18F]FDG-PET/MRI to [18F]FDG-PET/CT for detection of a potential primary cancer and metastases in patients suspected for cancer of unknown primary (CUP). Methods: A total of 20 patients (15 male, 5 female, age 53 ± 13 years) suspect for CUP underwent a dedicated head and neck & whole-body [18F]FDG-PET/CT (Biograph mCT 128, Siemens Healthcare) and a subsequent simultaneous [18F]FDG-PET/MRI examination (Biograph mMR, Siemens Healthcare). Two readers rated the datasets (PET/CT; PET/MRI) regarding the detection of the primary cancer and metastases, lesion conspicuity (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale). PET analysis comprised the assessment of maximum standardized uptake values (SUVmax) of all PET-positive lesions using volume of interest (VOI) analysis derived from the PET/CT and PET/MR datasets. All available data considering histology and imaging including prior and clinical follow-up examinations served as reference standard. Statistical analysis included comparison of mean values using Mann-Whitney U test and correlation of SUVmax using Pearson‘s correlation. Results: In 14 out of 20 patients 49 malignant lesions were present. The primary cancer could be correctly identified in 11/20 patients with both PET/CT and PET/MRI. PET/CT enabled the detection of a total 38 metastases, PET/MR respectively of 37 metastases (one lung metastasis <5mm was missed). PET/CT and

Hybrid imaging for detection of carcinoma of unknown primary: A preliminary comparison trial of whole-body PET/MRI versus PET/CT

Energy Technology Data Exchange (ETDEWEB)

Ruhlmann, Verena; Ruhlmann, Marcus; Bellendorf, Alexander [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Grueneisen, Johannes [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Sawicki, Lino M. [Department of Diagnostic and Interventional Radiology, University of Dusseldorf, Moorenstraße 5, 40225 Dusseldorf (Germany); Grafe, Hong [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Forsting, Michael [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Bockisch, Andreas [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany); Umutlu, Lale, E-mail: verena.ruhlmann@uk-essen.de [Department of Nuclear Medicine, University Hospital Essen, University Duisburg-Essen, Hufelandstr. 55, 45122 Essen (Germany)

2016-11-15

Highlights: • Both 18F-FDG PET/CT and 18F-FDG PET/MRI provide a comparable diagnostic ability for detection of primary cancer and metastases in CUP-syndrome. • Both imaging methods showed comparably high lesion conspicuity and diagnostic confidence (superior assessment of cervical lesions in PET/MRI). • PET/MRI may serve as a powerful alternative, particularly for therapy monitoring or surveillance considering the long-term cumulative dose. - Abstract: Purpose: The aim of this study is to evaluate and compare the diagnostic potential of integrated whole-body [18F]FDG-PET/MRI to [18F]FDG-PET/CT for detection of a potential primary cancer and metastases in patients suspected for cancer of unknown primary (CUP). Methods: A total of 20 patients (15 male, 5 female, age 53 ± 13 years) suspect for CUP underwent a dedicated head and neck & whole-body [18F]FDG-PET/CT (Biograph mCT 128, Siemens Healthcare) and a subsequent simultaneous [18F]FDG-PET/MRI examination (Biograph mMR, Siemens Healthcare). Two readers rated the datasets (PET/CT; PET/MRI) regarding the detection of the primary cancer and metastases, lesion conspicuity (4-point ordinal scale) and diagnostic confidence (3-point ordinal scale). PET analysis comprised the assessment of maximum standardized uptake values (SUVmax) of all PET-positive lesions using volume of interest (VOI) analysis derived from the PET/CT and PET/MR datasets. All available data considering histology and imaging including prior and clinical follow-up examinations served as reference standard. Statistical analysis included comparison of mean values using Mann-Whitney U test and correlation of SUVmax using Pearson‘s correlation. Results: In 14 out of 20 patients 49 malignant lesions were present. The primary cancer could be correctly identified in 11/20 patients with both PET/CT and PET/MRI. PET/CT enabled the detection of a total 38 metastases, PET/MR respectively of 37 metastases (one lung metastasis <5mm was missed). PET/CT and

Usefulness of Integrated PET/MRI in Head and Neck Cancer: A Preliminary Study

International Nuclear Information System (INIS)

Lee, Soo Jin; Seo, Hyo Jung; Cheon, Gi Jeong; Kim, Ji Hoon; Kim, E. Edmund; Kang, Keon Wook; Paeng, Jin Chul; Chung, Junekey; Lee, Dong Soo

2014-01-01

The new modality of an integrated positron emission tomography/magnetic resonance imaging (PET/MRI) has recently been introduced but not validated. Our objective was to evaluate clinical performance of 18 F-fluoro-2-deoxyglucose ( 18 F-FDG) PET/MRI in patients with head and neck cancer. This retrospective study was conducted between January 2013 and February 2013. Ten patients (eight men, two women; mean age, 61.4±13.4 years) with histologically proven head and neck tumors were enrolled.Whole-body PET/MRI and regional positron emission tomography (PET) with dedicated MRI were sequentially obtained. Maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume, total lesion glycolysis and contrast enhancement were analyzed. A total of ten whole-body positron emission tomography (PET), ten regional positron emission tomography (PET), ten dedicated MRI and ten regional PET/gadolinium-enhanced T1-weighted (Gd)-MRI images were analyzed for initial staging. Two nuclear medicine physicians analyzed positron emission tomography (PET) and PET/MRI with a consensus. One radiologist analyzed dedicated MRI. The primary lesions and number of metastatic lymph nodes analyzed from each image were compared. Eight patients were diagnosed with head and neck cancer (one tongue cancer, four tonsillar cancers, one nasopharyngeal cancer and two hypopharyngeal cancers) by histological diagnosis. Two benign tumors (pleomorphic adenoma and Warthin tumor) were diagnosed with surgical operation. Whole-body positron emission tomography (PET) and regional positron emission tomography (PET) attenuated by MRI showed good image quality for the lesion detection. Whole-body positron emission tomography (PET) and regional positron emission tomography (PET) detected ten primary sites and compensated for a missed lesion on dedicated MRI. A discordant number of suspicious lymph node metastases was noted according to the different images; 22, 16, 39 and 40 in the whole-body positron

Simulation of time curves in small animal PET using GATE

International Nuclear Information System (INIS)

Simon, Luc; Strul, Daniel; Santin, Giovanni; Krieguer, Magalie; Morel, Christian

2004-01-01

The ClearPET project of the Crystal Clear Collaboration (CCC) is building spin-off technology for high resolution small animal Positron Emission Tomography (PET). Monte Carlo simulation is essential for optimizing the specifications of these systems with regards to their most important characteristics, such as spatial resolution, sensitivity, or count rate performance. GATE, the Geant4 Application for Tomographic Emission simulates the passing of time during real acquisitions, allowing to handle dynamic systems such as decaying source distributions or moving detectors. GATE output is analyzed on an event-by-event basis. The time associated with each single event allows to sort coincidences and to model dead-time. This leads to the study of time curves for a prospective small animal PET scanner design. The count rates of true, and random coincidences are discussed together with the corresponding Noise Equivalent Count (NEC) rates as a function of some PET scanner specifications such as detector dead time, or coincidence time window

A retrospective comparison between {sup 68}Ga-DOTA-TOC PET/CT and {sup 18}F-DOPA PET/CT in patients with extra-adrenal paraganglioma

Energy Technology Data Exchange (ETDEWEB)

Kroiss, Alexander; Putzer, Daniel; Decristoforo, Clemens; Uprimny, Christian; Virgolini, Irene Johanna [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Frech, Andreas; Fraedrich, Gustav [Innsbruck Medical University, Department of Vascular Surgery, Innsbruck (Austria); Gasser, Rudolf Wolfgang [Innsbruck Medical University, Department of Internal Medicine I, Innsbruck (Austria); Shulkin, Barry Lynn [St. Jude Children' s Research Hospital, Department of Radiological Sciences, Memphis, TN (United States); Url, Christoph [Innsbruck Medical University, Department of Otorhinolaryngology, Innsbruck (Austria); Widmann, Gerlig [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria); Prommegger, Rupert [Sanatorium Kettenbruecke, Department of Surgery, Innsbruck (Austria); Sprinzl, Georg Mathias [State Clinic St. Poelten, Department of Otorhinolaryngology, St. Poelten (Austria)

2013-12-15

{sup 18}F-Fluoro-l-dihydroxyphenylalanine ({sup 18}F-DOPA) PET offers high sensitivity and specificity in the imaging of nonmetastatic extra-adrenal paragangliomas (PGL) but lower sensitivity in metastatic or multifocal disease. These tumours are of neuroendocrine origin and can be detected by {sup 68}Ga-DOTA-Tyr{sup 3}-octreotide ({sup 68}Ga-DOTA-TOC) PET. Therefore, we compared {sup 68}Ga-DOTA-TOC and {sup 18}F-DOPA as radiolabels for PET/CT imaging for the diagnosis and staging of extra-adrenal PGL. Combined cross-sectional imaging was the reference standard. A total of 5 men and 15 women (age range 22 to 73 years) with anatomical and/or histologically proven extra-adrenal PGL were included in this study. Of these patients, 5 had metastatic or multifocal lesions and 15 had single sites of disease. Comparative evaluation included morphological imaging with CT and functional imaging with {sup 68}Ga-DOTA-TOC PET and {sup 18}F-DOPA PET. The imaging results were analysed on a per-patient and a per-lesion basis. The maximum standardized uptake value (SUV{sub max}) of each functional imaging modality in concordant tumour lesions was measured. Compared with anatomical imaging, {sup 68}Ga-DOTA-TOC PET and {sup 18}F-DOPA PET each had a per-patient and per-lesion detection rate of 100 % in nonmetastatic extra-adrenal PGL. However, in metastatic or multifocal disease, the per-lesion detection rate of {sup 68}Ga-DOTA-TOC was 100 % and that of {sup 18}F-DOPA PET was 56.0 %. Overall, {sup 68}Ga-DOTA-TOC PET identified 45 lesions; anatomical imaging identified 43 lesions, and {sup 18}F-DOPA PET identified 32 lesions. The overall per-lesion detection rate of {sup 68}Ga-DOTA-TOC PET was 100 % (McNemar, P < 0.5), and that of {sup 18}F-DOPA PET was 71.1 % (McNemar, P < 0.001). The SUV{sub max} (mean {+-} SD) of all 32 concordant lesions was 67.9 {+-} 61.5 for {sup 68}Ga-DOTA-TOC PET and 11.8 {+-} 7.9 for {sup 18}F-DOPA PET (Mann-Whitney U test, P < 0.0001). {sup 68}Ga-DOTA-TOC PET

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

Energy Technology Data Exchange (ETDEWEB)

Luboldt, Wolfgang [Multiorgan Screening Foundation, Frankfurt (Germany); University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany); University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Volker, Teresa; Zoephel, Klaus; Kotzerke, Joerg [University Hospital Dresden, Clinic and Policlinic of Nuclear Medicine, Dresden (Germany); Wiedemann, Baerbel [University Hospital Dresden, Institute of Medical Informatics and Biometrics, Dresden (Germany); Wehrmann, Ursula [University Hospital Dresden, Clinic and Policlinic of Surgery, Dresden (Germany); Koch, Arne; Abolmaali, Nasreddin [University Hospital Dresden, Oncoray, Dresden (Germany); Toussaint, Todd; Luboldt, Hans-Joachim [Multiorgan Screening Foundation, Frankfurt (Germany); Middendorp, Markus; Gruenwald, Frank [University Hospital Frankfurt, Department of Nuclear Medicine, Frankfurt (Germany); Aust, Daniela [University Hospital Dresden, Department of Pathology, Dresden (Germany); Vogl, Thomas J. [University Hospital Frankfurt, Department of Radiology, Frankfurt am Main (Germany)

2010-09-15

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas {>=}10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 x 6+5 x 2)=484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUV{sub max} was {>=}5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV{sub max}. FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV{sub max}{>=} 5 improves the accuracy. (orig.)

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

International Nuclear Information System (INIS)

Luboldt, Wolfgang; Volker, Teresa; Zoephel, Klaus; Kotzerke, Joerg; Wiedemann, Baerbel; Wehrmann, Ursula; Koch, Arne; Abolmaali, Nasreddin; Toussaint, Todd; Luboldt, Hans-Joachim; Middendorp, Markus; Gruenwald, Frank; Aust, Daniela; Vogl, Thomas J.

2010-01-01

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas ≥10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off. 84 patients, who underwent PET/CT and colonoscopy (n=79)/sigmoidoscopy (n=5) for (79 x 6+5 x 2)=484 colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs. Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n=23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n=10) the SUV max was ≥5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV max . FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV max ≥ 5 improves the accuracy. (orig.)

PET/CT colonography in patients with colorectal polyps: a feasibility study

International Nuclear Information System (INIS)

Mainenti, Pier P.; Pace, Leonardo; Salvatore, Marco; Salvatore, Barbara; D'Antonio, Dario; Bucci, Luigi; De Falco, Teresa; De Palma, Giovanni D.; D'Armiento, Francesco P.

2007-01-01

To examine: (1) the feasibility of PET/CT colonography (PET/CTc) in patients with colorectal polyps; (2) the impact of metabolic information on CTc interpretation and, conversely, the impact of morphological information on PET characterisation of focal colorectal uptake. Ten patients with colorectal polyps underwent PET/CTc, followed within 3 h by therapeutic conventional colonoscopy (CC). A radiologist and a nuclear medicine physician analysed the PET/CTc images. The agreement of morphological and metabolic information in the colon and rectum was evaluated. The sensitivity and specificity of PET, CT and PET/CT were calculated for colorectal polyps. Seventeen polypoid lesions were identified at CC: six≤5 mm, six between 6 and 9 mm, and five ≥10 mm (four hyperplastic polyps, 11 tubular adenomas, one adenocarcinoma and one submucosal lipoma). A total of 20 scans (supine and prone) were performed in the ten patients: the agreement of morphological and metabolic information was excellent in 17 scans, good in two and moderate in one. PET/CTc showed a sensitivity of 91% for lesions ≥6 mm and a specificity of 100%. The metabolic information did not disclose any further polyps missed on CTc. The morphological information permitted correct classification of all eight instances of focal radiotracer uptake. PET/CTc is a feasible study. Adding a colonographic protocol to PET/CT images seems to allow correct characterisation of all cases of colorectal focal radiotracer uptake. The metabolic information does not seem to increase the accuracy of CTc. (orig.)

Evaluation of {sup 68}Ga-DOTATOC PET/MRI for whole-body staging of neuroendocrine tumours in comparison with {sup 68}Ga-DOTATOC PET/CT

Energy Technology Data Exchange (ETDEWEB)

Sawicki, Lino M. [University Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Dusseldorf (Germany); University Duisburg-Essen, Department of Nuclear Medicine, Medical Faculty, Essen (Germany); Deuschl, Cornelius; Beiderwellen, Karsten; Forsting, Michael; Umutlu, Lale [University Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Medical Faculty, Essen (Germany); Ruhlmann, Verena; Poeppel, Thorsten D.; Bockisch, Andreas; Herrmann, Ken [University Duisburg-Essen, Department of Nuclear Medicine, Medical Faculty, Essen (Germany); Heusch, Philipp; Antoch, Gerald [University Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Dusseldorf (Germany); Lahner, Harald; Fuehrer, Dagmar [University Duisburg-Essen, Department of Endocrinology and Metabolism, Endocrine Tumour Center at WTZ and ENETS Center of Excellence, Medical Faculty, Essen (Germany); Endocrine Tumour Center at WTZ and ENETS Center of Excellence, Essen (Germany)

2017-10-15

To compare the diagnostic performance of {sup 68}Ga-DOTATOC PET/MRI and {sup 68}Ga-DOTATOC PET/CT in the whole-body staging of patients with neuroendocrine tumours (NET). Thirty patients with histopathologically confirmed NET underwent PET/CT and PET/MRI in a single-injection protocol. PET/CT and PET/MRI scans were prospectively evaluated with regard to lesion count, localization, nature (NET/non-NET), and conspicuity (four-point scale). Histopathology and follow-up imaging served as the reference standards. The proportions of NET and non-NET lesions rated correctly were compared using McNemar's chi-squared test. The Wilcoxon test was used to assess differences in SUVmax and lesion conspicuity. The correlation between the SUVmax for the same lesions from each modality was analysed using Pearson's correlation coefficient (r). According to the reference standard, there were 197 lesions (142 NET, 55 non-NET). Lesion-based analysis showed a higher proportion of correctly rated NET lesions on PET/MRI than on PET/CT (90.8% vs. 86.7%, p = 0.031), whereas on PET/CT there was a higher proportion of correctly rated non-NET lesions (94.5% vs. 83.6%, p = 0.031). SUVmax was strongly correlated (r = 0.86; p < 0.001) and did not differ significantly (p = 0.35) between the modalities. Overall conspicuity and NET lesion conspicuity were higher on PET/MRI (both p < 0.01). Ga-DOTATOC PET/MRI yielded a higher proportion of correctly rated NET lesions and should be regarded as a valuable alternative to {sup 68}Ga-DOTATOC PET/CT in whole-body staging of NET patients. (orig.)

Interference between PET and MRI sub-systems in a silicon-photomultiplier-based PET/MRI system

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Watabe, Hiroshi; Kanai, Yasukazu; Hatazawa, Jun; Aoki, Masaaki; Sugiyama, Eiji; Watabe, Tadashi; Imaizumi, Masao; Shimosegawa, Eku

2011-01-01

The silicon-photomultiplier (Si-PM) is a promising photodetector, especially for integrated PET/MRI systems, due to its small size, high gain, and low sensitivity to static magnetic fields. The major problem using a Si-PM-based PET system within the MRI system is the interference between the PET and MRI units. We measured the interference by combining a Si-PM-based PET system with a permanent-magnet MRI system. When the RF signal-induced pulse height exceeded the lower energy threshold level of the PET system, interference between the Si-PM-based PET system and MRI system was detected. The prompt as well as the delayed coincidence count rates of the Si-PM-based PET system increased significantly. These noise counts produced severe artifacts on the reconstructed images of the Si-PM-based PET system. In terms of the effect of the Si-PM-based PET system on the MRI system, although no susceptibility artifact was observed on the MR images, electronic noise from the PET detector ring was detected by the RF coil and reduced the signal-to-noise ratio (S/N) of the MR images. The S/N degradation of the MR images was reduced when the distance between the RF coil and the Si-PM-based PET system was increased. We conclude that reducing the interference between the PET and MRI systems is essential for achieving the optimum performance of integrated Si-PM PET/MRI systems.

Validity of using a 3-dimensional PET scanner during inhalation of 15O-labeled oxygen for quantitative assessment of regional metabolic rate of oxygen in man

Science.gov (United States)

Hori, Yuki; Hirano, Yoshiyuki; Koshino, Kazuhiro; Moriguchi, Tetsuaki; Iguchi, Satoshi; Yamamoto, Akihide; Enmi, Junichiro; Kawashima, Hidekazu; Zeniya, Tsutomu; Morita, Naomi; Nakagawara, Jyoji; Casey, Michael E.; Iida, Hidehiro

2014-09-01

Use of 15O labeled oxygen (15O2) and positron emission tomography (PET) allows quantitative assessment of the regional metabolic rate of oxygen (CMRO2) in vivo, which is essential to understanding the pathological status of patients with cerebral vascular and neurological disorders. The method has, however, been challenging, when a 3D PET scanner is employed, largely attributed to the presence of gaseous radioactivity in the trachea and the inhalation system, which results in a large amount of scatter and random events in the PET assessment. The present study was intended to evaluate the adequacy of using a recently available commercial 3D PET scanner in the assessment of regional cerebral radioactivity distribution during an inhalation of 15O2. Systematic experiments were carried out on a brain phantom. Experiments were also performed on a healthy volunteer following a recently developed protocol for simultaneous assessment of CMRO2 and cerebral blood flow, which involves sequential administration of 15O2 and C15O2. A particular intention was to evaluate the adequacy of the scatter-correction procedures. The phantom experiment demonstrated that errors were within 3% at the practically maximum radioactivity in the face mask, with the greatest radioactivity in the lung. The volunteer experiment demonstrated that the counting rate was at peak during the 15O gas inhalation period, within a verified range. Tomographic images represented good quality over the entire FOV, including the lower part of the cerebral structures and the carotid artery regions. The scatter-correction procedures appeared to be important, particularly in the process to compensate for the scatter originating outside the FOV. Reconstructed images dramatically changed if the correction was carried out using inappropriate procedures. This study demonstrated that accurate reconstruction could be obtained when the scatter compensation was appropriately carried out. This study also suggested the

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

International Nuclear Information System (INIS)

Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

2015-01-01

Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

Energy Technology Data Exchange (ETDEWEB)

Jung, Jin Ho; Choi, Yong, E-mail: ychoi.image@gmail.com; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun [Department of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 121-742 (Korea, Republic of); Oh, Chang Hyun; Park, Hyun-wook [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Kyung Min; Kim, Jong Guk [Korea Institute of Radiological and Medical Science, 75 Nowon-ro, Nowon-gu, Seoul 139-709 (Korea, Republic of)

2015-05-15

Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

Imaging large vessel vasculitis with fully integrated PET/MRI: a pilot study

International Nuclear Information System (INIS)

Einspieler, Ingo; Pyka, Thomas; Eiber, Matthias; Thuermel, Klaus; Wolfram, Sabine; Moog, Philipp; Reeps, Christian; Essler, Markus

2015-01-01

The aim of this study was to evaluate the feasibility of hybrid [ 18 F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI in patients with large vessel vasculitis (LVV) by comparing visual and quantitative parameters to that of PET/CT. Furthermore, the value of PET/MRI in disease activity and extent of LVV was assessed. A total of 16 [ 18 F]FDG PET/MRI and 12 [ 18 F]-FDG PET/CT examinations were performed in 12 patients with LVV. MRI of the vessel wall by T1-weighted and T2-weighted sequences was used for anatomical localization of FDG uptake and identification of morphological changes associated with LVV. In addition, contrast-enhanced (CE) magnetic resonance angiography (MRA) was performed. The vascular FDG uptake in the vasculitis group was compared to a reference group of 16 patients using a four-point visual score. Visual scores and quantitative parameters [maximum standardized uptake value (SUV max ) and target to background ratio (TBR)] were compared between PET/MRI and PET/CT. Furthermore, correlations between C-reactive protein (CRP) and quantitative PET results, as well the extent of vasculitis in PET, MRI/CE-MRA and combined PET/MRI, were analysed. TBRs, SUV max values and visual scores correlated well between PET/MRI and PET/CT (r = 0.92, r = 0.91; r = 0.84, p < 0.05). There was no significant difference between both modalities concerning SUV max measurements and visual scores. In PET/MRI, PET alone revealed abnormal FDG uptake in 86 vascular regions. MRI/CE-MRA indicated 49 vessel segments with morphological changes related to vasculitis, leading to a total number of 95 vasculitis regions in combination with PET. Strong and significant correlations between CRP and disease extent in PET alone (r = 0.75, p = 0.0067) and PET/MRI (r = 0.92, p < 0.0001) in contrast to MRI/CE-MRA only were observed. Regarding disease activity, no significant correlations were seen between quantitative PET results and CRP, although there was a trend towards

Imaging large vessel vasculitis with fully integrated PET/MRI: a pilot study

Energy Technology Data Exchange (ETDEWEB)

Einspieler, Ingo; Pyka, Thomas; Eiber, Matthias [Technische Universitaet Muenchen, Klinikum rechts der Isar, Department of Nuclear Medicine, Munich (Germany); Thuermel, Klaus; Wolfram, Sabine; Moog, Philipp [Technische Universitaet Muenchen, Klinikum rechts der Isar, Department of Nephrology, Munich (Germany); Reeps, Christian [Technische Universitaet Muenchen, Department of Vascular Surgery, Klinikum rechts der Isar, Munich (Germany); Essler, Markus [Rheinische Friedrich-Wilhelms-Universitaet, Department of Nuclear Medicine, Universitaetsklinikum Bonn, Bonn (Germany)

2015-04-16

The aim of this study was to evaluate the feasibility of hybrid [{sup 18}F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI in patients with large vessel vasculitis (LVV) by comparing visual and quantitative parameters to that of PET/CT. Furthermore, the value of PET/MRI in disease activity and extent of LVV was assessed. A total of 16 [{sup 18}F]FDG PET/MRI and 12 [{sup 18}F]-FDG PET/CT examinations were performed in 12 patients with LVV. MRI of the vessel wall by T1-weighted and T2-weighted sequences was used for anatomical localization of FDG uptake and identification of morphological changes associated with LVV. In addition, contrast-enhanced (CE) magnetic resonance angiography (MRA) was performed. The vascular FDG uptake in the vasculitis group was compared to a reference group of 16 patients using a four-point visual score. Visual scores and quantitative parameters [maximum standardized uptake value (SUV{sub max}) and target to background ratio (TBR)] were compared between PET/MRI and PET/CT. Furthermore, correlations between C-reactive protein (CRP) and quantitative PET results, as well the extent of vasculitis in PET, MRI/CE-MRA and combined PET/MRI, were analysed. TBRs, SUV{sub max} values and visual scores correlated well between PET/MRI and PET/CT (r = 0.92, r = 0.91; r = 0.84, p < 0.05). There was no significant difference between both modalities concerning SUV{sub max} measurements and visual scores. In PET/MRI, PET alone revealed abnormal FDG uptake in 86 vascular regions. MRI/CE-MRA indicated 49 vessel segments with morphological changes related to vasculitis, leading to a total number of 95 vasculitis regions in combination with PET. Strong and significant correlations between CRP and disease extent in PET alone (r = 0.75, p = 0.0067) and PET/MRI (r = 0.92, p < 0.0001) in contrast to MRI/CE-MRA only were observed. Regarding disease activity, no significant correlations were seen between quantitative PET results and CRP, although there

Oncologic PET/CT: current status and controversies

International Nuclear Information System (INIS)

Siegel, B.A.; Dehdashti, F.

2005-01-01

The introduction of integrated PET/CT has dramatically increased the worldwide rate of growth for PET, predominantly for oncologic imaging with the glucose analog 18 F-fluorodeoxyglucose (FDG). A rapidly expanding body of literature demonstrates that the use FDG-PET/CT and the resultant ability to interpret coregistered and fused PET and CT images lead to improved observer confidence and improved diagnostic performance by comparison with PET alone, CT alone, and visually correlated PET and CT. The value of PET/CT is likely to be even greater with new PET radiopharmaceuticals under development, many of which produce PET images with even fewer anatomical landmarks than FDG images. PET/CT is also likely to lead to the resurrection of 18 F-fluoride as a principal agent for radionuclide bone imaging. There are a number of controversies related to PET/CT, including minimum training and experience requirements for interpreting physicians and defining new models for technical and professional reimbursement. (orig.)

PET/CT in therapy evaluation of patients with lung cancer

DEFF Research Database (Denmark)

Langer, Natasha Hemicke; Christensen, Tine Nøhr; Langer, Seppo W

2014-01-01

FDG-PET/CT is a well documented and widespread used imaging modality for the diagnosis and staging of patient with lung cancer. FDG-PET/CT is increasingly used for the assessment of treatment effects during and after chemotherapy. However, PET is not an accepted surrogate end-point for assessment...... of response rate in clinical trials. The aim of this review is to present current evidence on the use of PET in response evaluation of patients with lung cancer and to introduce the pearls and pitfalls of the PET-technology relating to response assessment. Based on this and relating to validation criteria......, including stable technology, standardization, reproducibility and broad availability, the review discusses why, despite numerous studies on response assessment indicating a possible role for FDG-PET/CT, PET still has no place in guidelines relating to response evaluation in lung cancer....

Effect of selecting a fixed dephosphorylation rate on the estimation of rate constants and rCMRGlu from dynamic [18F] fluorodeoxyglucose/PET data

International Nuclear Information System (INIS)

Dhawan, V.; Moeller, J.R.; Strother, S.C.; Evans, A.C.; Rottenberg, D.A.

1989-01-01

Several publications have discussed the estimation and physiologic significance of regional [ 18 F]fluorodeoxyglucose (FDG) rate constants and metabolic rates. Most of these studies analyzed dynamic data collected over 45-60 min; three rate constants (k1-k3) and blood volume (Vb) were estimated and the regional cerebral metabolic rate for glucose (rCMRGlu) was subsequently derived using the measured blood glucose value and a regionally invariant value of the lumped constant (LC). The dephosphorylation rate constant (k4) was either neglected, or a fixed value was used in the estimation procedure to obtain the remaining parameters. To compare the rate constants obtained by different authors using different values of k4 is impossible without knowledge of the effect of selecting different fixed values of k4 (including zero) on the estimated rate constants and rCMRGlu. Based on our analysis of FDG/PET data from nine normal volunteer subjects, we conclude that inclusion of a fixed value for k4, in spite of a scaling effect on the absolute values of model parameters, has no effect on the coefficient of variation (CV) of within- and between-subject parameter estimates and glucose metabolic rates

PET and PET-CT. State of the art and future prospects

International Nuclear Information System (INIS)

Fanti, Stefano; Franchi, Roberto; Battista, Giuseppe; Monetti, Nino; Canini, Romeo

2005-01-01

Fluoro-deoxyglucose positron emission tomography (FDG PET) enables the in vivo study of tissue metabolism, and thus is able to identify malignant tumours as hypermetabolic lesions by an increase in tracer uptake. Many papers have demonstrated both the relevant impact of FDG PET on staging of many cancers and the superior accuracy of the technique compared with conventional diagnostic methods for pre-treatment evaluation, therapy response evaluation and relapse identification. In particular PET was found useful in identifying lymph nodal and metastatic spread. thus altering patient management in more than 30% of cases. PET images, however, provide limited anatomical data, which in regions such as the head and neck, mediastinum and pelvic cavity is a significant drawback. The exact localization of lesions may also be difficult in some cases, on the basis of PET images alone. The introduction of combined PET-computed tomography (PET-CT) scanners enables the almost simultaneous acquisition of transmission and emission images, thus obtaining optimal fusion images in a very short time. PET-CT fusion images enable lesions to be located, reducing false positive studies and increasing accuracy; the overall duration of examination may also be reduced. On the basis of both literature data and our experience we established the clinical indications when PET-CT may be particularly useful, in comparison with PET alone. It should also be underlined that the use of PET-CT is almost mandatory for new traces such as C-choline and C-methionine; these new tracers may be applied for studying tumours not assessable with FDG, such as prostate cancer. In conclusion PET-CT is at present the most advanced method for metabolic imaging, and is capable of precisely localizing and assessing tumours; fusion images reduce false positive and inconclusive studies, thus increasing diagnostic accuracy [it

'PET -Compton' system. Comparative evaluation with PET system using Monte Carlo simulation

International Nuclear Information System (INIS)

Diaz Garcia, Angelina; Arista Romeu, Eduardo; Abreu Alfonso, Yamiel; Leyva Fabelo, Antonio; Pinnera Hernandez, Ibrahin; Bolannos Perez, Lourdes; Rubio Rodriguez, Juan A; Perez Morales, Jose M.; Arce Dubois, Pedro; Vela Morales, Oscar; Willmott Zappacosta, Carlos

2011-01-01

Positron Emission Tomography (PET) in small animals has actually achieved spatial resolution round about 1 mm and currently there are under study different approaches to improve this spatial resolution. One of them combines PET technology with Compton Cameras. This paper presents the idea of the so called 'PET-Compton' systems and includes comparative evaluation of spatial resolution and global efficiency in both PET and PET-Compton system by means of Monte Carlo simulations using Geant4 code. Simulation is done on a PET-Compton system consisting of LYSO-LuYAP scintillating detectors of particular small animal PET scanner named 'Clear-PET' and for Compton detectors based on CdZnTe semiconductor. A group of radionuclides that emits a positron (e + ) and γ quantum almost simultaneously and fulfills some selection criteria for their possible use in PET-Compton systems for medical and biological applications were studied under simulation conditions. (Author)

Optimization for PET imaging based on phantom study and NECdensity

International Nuclear Information System (INIS)

Daisaki, Hiromitsu; Shimada, Naoki; Shinohara, Hiroyuki

2012-01-01

In consideration of the requirement for global standardization and quality control of PET imaging, the present studies gave an outline of phantom study to decide both scan and reconstruction parameters based on FDG-PET/CT procedure guideline in Japan, and optimization of scan duration based on NEC density was performed continuously. In the phantom study, scan and reconstruction parameters were decided by visual assessment and physical indexes (N 10mm , NEC phantom , Q H,10mm /N 10mm ) to visualize hot spot of 10 mm diameter with standardized uptake value (SUV)=4 explicitly. Simultaneously, Recovery Coefficient (RC) was evaluated to recognize that PET images had enough quantifiably. Scan durations were optimized by Body Mass Index (BMI) based on retrospective analysis of NEC density . Correlation between visual score in clinical FDG-PET images and NEC density fell after the optimization of scan duration. Both Inter-institution and inter-patient variability were decreased by performing the phantom study based on the procedure guideline and the optimization of scan duration based on NEC density which seem finally useful to practice highly precise examination and promote high-quality controlled study. (author)

Non-invasive Estimation of Metabolic Uptake Rate of Glucose using F18-FDG PET and Linear Transformation of Outputs

DEFF Research Database (Denmark)

Christensen, Anders Nymark; Reichkendler, M.; Auerback, P.

For quantitative analysis and kinetic modeling of dynamic PET-data an input function is needed. Normally this is obtained by arterial blood sampling, potentially an unpleasant experience for the patient and laborious for the staff. Aim: To validate methods for determination of the metabolic uptake...... rate (Km) of glucose from dynamic FDG-PET scans using Image Derived Input Functions (IDIF) without blood sampling. Method: We performed 24 dynamic FDG-PET scans of the thigh of 14 healthy young male volunteers during a hyperinsulinemic isoglycemic clamp. Ten of the subjects were scanned twice 11 weeks...... artery diameter in the material, the method should also be applicable to women and people of other ages, but used with caution in the elderly due to variance in intramuscular adipose distribution. If only Km and no other kinetic parameters are needed, the described method with transformation...

'Number-forms' in neuroimaging?;- a PET activation study

International Nuclear Information System (INIS)

Cowell, S.F.; Code, C.; Harasty, J.; Egan, G.F.; Watson, J.D.G.; University of New South Wales,; Royal Prince Alfred Hospital, Sydney, NSW; University of Melbourne, VIC; University of Exeter,

2000-01-01

Full text: In 1880 Francis Galton reported a mental imagery study in which imagers were able to describe and draw arithmetic operations called 'number-forms' (NF). While many studies have reported NFs, little is known about their neural basis. We report a PET case study of a normal volunteer who invoked NFs during mental arithmetic tasks. This PET study used two conditions, repetition and calculation, presented bi-aurally while the subject was blindfolded. The calculation condition required the subject to say out loud the answers to arithmetic tasks, eg. 'nineteen minus seven'. A post-test protocol for vividness of visual imagery during calculation (PVVIC), based on the interviews of Galton (1880) and Seron and colleagues (1992), identified AF, a 43year-old women, as the highest imager (PVVIC - 95%) from a group of 12 normal volunteers. She was able to accurately describe and draw a well-used imagery strategy for mental arithmetic. Her results were contrasted with non-imager, FM (PVVIC - 10%). AF's MRI guided PET results showed significant rCBF activations during the calculation tasks including the right precuneus, right superior frontal gyrus (BA8), left superior parietal lobe (BA7), left visual cortex, medial thalamus and cerebellum. Except for the activation in the right BA8, common to both subjects, AF's areas were not activated by FM. These data confirm previous PET findings that the precuneus plays a major role in mental imagery and point to a neural network for mental imagery during simple calculation. AF's imagery strategies could be the first number-forms reported in a neuroimaging study. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Quantitative dynamic ¹⁸FDG-PET and tracer kinetic analysis of soft tissue sarcomas.

Science.gov (United States)

Rusten, Espen; Rødal, Jan; Revheim, Mona E; Skretting, Arne; Bruland, Oyvind S; Malinen, Eirik

2013-08-01

To study soft tissue sarcomas using dynamic positron emission tomography (PET) with the glucose analog tracer [(18)F]fluoro-2-deoxy-D-glucose ((18)FDG), to investigate correlations between derived PET image parameters and clinical characteristics, and to discuss implications of dynamic PET acquisition (D-PET). D-PET images of 11 patients with soft tissue sarcomas were analyzed voxel-by-voxel using a compartment tracer kinetic model providing estimates of transfer rates between the vascular, non-metabolized, and metabolized compartments. Furthermore, standard uptake values (SUVs) in the early (2 min p.i.; SUVE) and late (45 min p.i.; SUVL) phases of the PET acquisition were obtained. The derived transfer rates K1, k2 and k3, along with the metabolic rate of (18)FDG (MRFDG) and the vascular fraction νp, was fused with the computed tomography (CT) images for visual interpretation. Correlations between D-PET imaging parameters and clinical parameters, i.e. tumor size, grade and clinical status, were calculated with a significance level of 0.05. The temporal uptake pattern of (18)FDG in the tumor varied considerably from patient to patient. SUVE peak was higher than SUVL peak for four patients. The images of the rate constants showed a systematic pattern, often with elevated intensity in the tumors compared to surrounding tissue. Significant correlations were found between SUVE/L and some of the rate parameters. Dynamic (18)FDG-PET may provide additional valuable information on soft tissue sarcomas not obtainable from conventional (18)FDG-PET. The prognostic role of dynamic imaging should be investigated.

Cerebral FDG-PET scanning abnormalities in optimally treated HIV patients

DEFF Research Database (Denmark)

Andersen, Ase B; Law, Ian; Krabbe, Karen S

2010-01-01

with no history of virological failure, a CD4 count above 200 x 106 cells/l and no other co-morbidities. The distribution of the regional cerebral metabolic rate of glucose metabolism was measured using fluorine-18-flourodeoxyglucose positron emission tomography (FDG-PET) scanning. The PET scans were evaluated...... in the relative metabolic rate of glucose. Compared to healthy subjects, the patients with abnormal FDG-PET scanning results had a shorter history of known HIV infection, fewer years on antiretroviral therapy and higher levels of circulating TNF alpha and IL-6 (p = 0.08). CONCLUSION: A large proportion...... of optimally treated HIV patients exhibit cerebral FDG-PET scanning abnormalities and elevated TNF alpha and IL-6 levels, which may indicate imminent neuronal damage. The neuroprotective effect of early ARV treatment should be considered in future prospective follow-up studies....

PET and PET/CT in tumour of undetermined origin

International Nuclear Information System (INIS)

Garcia O, J.R.

2007-01-01

In this presentation the following conclusions were obtained regarding the use of PET and PET/CT in patient with cancer of unknown primary: 1. Detection of the primary one in 1/3 at 1/2 of patient. 2. It detects metastases in other places in 50%. 3. It changes the initial therapy planned in 1/3 at 1/2 of patient. 4. Useful in initial phases of protocol study to limit the other procedures. After standard evaluation. Before advanced protocol. 5. PET/CT study increases the % of primary detection, although in a non significant way vs. PET. 6. They are required more studies to value their utility to a more objective manner. (Author)

Positron emission tomography (PET) for oncologic applications in oral region

International Nuclear Information System (INIS)

Shozushima, Masanori; Terasaki, Kazunori

2004-01-01

A rapidly emerging clinical application of positron emission tomography (PET) is the detection of cancer with radionuclide tracer, because it provides information unavailable by ultrasound, computed tomography or magnetic resonance imaging. The most commonly used radiotracer for PET oncologic imaging is fluorine-18-labeled fluorodeoxyglucose ( 18 F-FDG). Early studies show PET has potential value in viewing the region of the tumor, detecting, staging, grading, monitoring response to anticancer therapy, and differentiating recurrent or residual disease from post treatment changes. However, limitations of FDG-PET in the head and neck region, namely, physiological FDG uptake in the salivary glands and palatine tonsils, have been reported, increasing the false-positive rates in image interpretation. This review was designed to address these distinctions of oral cancer PET imaging: specialization of PET equipment, cancer cell metabolism, proliferation and tracers, clinical diagnosis of oral cancer with PET, pitfalls in oncologic diagnosis with FDG-PET imaging. (author)

Medical application of PET technology

International Nuclear Information System (INIS)

Lim, Sang Moo; Choi, C. W.; An, S. H.; Woo, K. S.; Chung, W. S.; Yang, S. D.; Jun, G. S. and others

1999-04-01

We performed following studies using PET technology: 1. Clinical usefulness of [ 18 F]FDG whole body PET in malignant disease 2. Clinical usefulness of quantitative evaluation of F-18-FDG 3. Pilot study of C-11 methionine PET in brain tumor 4. PET study in patients with Parkinson's disease 5. A study on the clinical myocardial PET image. PET gives various metabolic information for the living human body, and is very important, new diagnostic modality. The PET study will give us the information of cancer patients such as early detection of cancer, staging, recurrence detection and characterization of cancer. The quantitative analysis using PET could be applied to evaluate the pathophysiology of various diseases and develop new drugs and develop new radiopharmaceuticals

Medical application of PET technology

Energy Technology Data Exchange (ETDEWEB)

Lim, Sang Moo; Choi, C. W.; An, S. H.; Woo, K. S.; Chung, W. S.; Yang, S. D.; Jun, G. S. and others

1999-04-01

We performed following studies using PET technology: 1. Clinical usefulness of [{sup 18}F]FDG whole body PET in malignant disease 2. Clinical usefulness of quantitative evaluation of F-18-FDG 3. Pilot study of C-11 methionine PET in brain tumor 4. PET study in patients with Parkinson's disease 5. A study on the clinical myocardial PET image. PET gives various metabolic information for the living human body, and is very important, new diagnostic modality. The PET study will give us the information of cancer patients such as early detection of cancer, staging, recurrence detection and characterization of cancer. The quantitative analysis using PET could be applied to evaluate the pathophysiology of various diseases and develop new drugs and develop new radiopharmaceuticals.

Improvement of PET surface hydrophilicity and roughness through blending

Energy Technology Data Exchange (ETDEWEB)

Kolahchi, Ahmad Rezaei; Ajji, Abdellah; Carreau, Pierre J. [CREPEC, Chemical Engineering Department, Polytechnique Montreal, 2500 chemin de Polytechnique, Quebec, Montreal (Canada)

2015-05-22

Controlling the adhesion of the polymer surface is a key issue in surface science, since polymers have been a commonly used material for many years. The surface modification in this study includes two different aspects. One is to enhance the hydrophilicity and the other is to create the roughness on the PET film surface. In this study we developed a novel and simple approach to modify polyethylene terephthalate (PET) film surface through polymer blending in twin-screw extruder. One example described in the study uses polyethylene glycol (PEG) in polyethylene terephthalate (PET) host to modify a PET film surface. Low content of polystyrene (PS) as a third component was used in the system to increase the rate of migration of PEG to the surface of the film. Surface enrichment of PEG was observed at the polymer/air interface of the polymer film containing PET-PEG-PS whereas for the PET-PEG binary blend more PEG was distributed within the bulk of the sample. Furthermore, a novel method to create roughness at the PET film surface was proposed. In order to roughen the surface of PET film, a small amount of PKHH phenoxy resin to change PS/PET interfacial tension was used. The compatibility effect of PKHH causes the formation of smaller PS droplets, which were able to migrate more easily through PET matrix. Consequently, resulting in a locally elevated concentration of PS near the surface of the film. The local concentration of PS eventually reached a level where a co-continuous morphology occurred, resulting in theinstabilities on the surface of the film.

Small animal PET: aspects of performance assessment

International Nuclear Information System (INIS)

Weber, Simone; Bauer, Andreas

2004-01-01

Dedicated small animal positron emission tomography (PET) systems are increasingly prevalent in industry (e.g. for preclinical drug development) and biological research. Such systems permit researchers to perform animal studies of a longitudinal design characterised by repeated measurements in single animals. With the advent of commercial systems, scanners have become readily available and increasingly popular. As a consequence, technical specifications are becoming more diverse, making scanner systems less broadly applicable. The investigator has, therefore, to make a decision regarding which type of scanner is most suitable for the intended experiments. This decision should be based on gantry characteristics and the physical performance. The first few steps have been taken towards standardisation of the assessment of performance characteristics of dedicated animal PET systems, though such assessment is not yet routinely implemented. In this review, we describe current methods of evaluation of physical performance parameters of small animal PET scanners. Effects of methodologically different approaches on the results are assessed. It is underscored that particular attention has to be paid to spatial resolution, sensitivity, scatter fraction and count rate performance. Differences in performance measurement methods are described with regard to commercially available systems, namely the Concorde MicroPET systems P4 and R4 and the quad-HIDAC. Lastly, consequences of differences in scanner performance parameters are rated with respect to applications of small animal PET. (orig.)

Advances in prostate-specific membrane antigen PET of prostate cancer.

Science.gov (United States)

Bouchelouche, Kirsten; Choyke, Peter L

2018-05-01

In recent years, a large number of reports have been published on prostate-specific membrane antigen (PSMA)/PET in prostate cancer (PCa). This review highlights advances in PSMA PET in PCa during the past year. PSMA PET/computed tomography (CT) is useful in detection of biochemical recurrence, especially at low prostate-specific antigen (PSA) values. The detection rate of PSMA PET is influenced by PSA level. For primary PCa, PSMA PET/CT shows promise for tumour localization in the prostate, especially in combination with multiparametric MRI (mpMRI). For primary staging, PSMA PET/CT can be used in intermediate and high-risk PCa. Intraoperative PSMA radioligand guidance seems promising for detection of malignant lymph nodes. While the use of PSMA PET/MRI in primary localized disease is limited to high and intermediate-risk patients and localized staging, in the recurrence setting, PET/MRI can be particularly helpful when the lesions are subtle. PSMA PET/CT is superior to choline PET/CT and other conventional imaging modalities. Molecular imaging with PSMA PET continues to pave the way for personalized medicine in PCa.However, large prospective clinical studies are still needed to fully evaluate the role of PSMA PET/CT and PET/MRI in the clinical workflow of PCa.

Scanning electron microscopic study of hazardous waste flakes of polyethylene terephthalate (PET) by aminolysis and ammonolysis

Energy Technology Data Exchange (ETDEWEB)

Mittal, Alok, E-mail: aljymittal@yahoo.co.in [Department of Chemistry, Maulana Azad National Institute of Technology (A Deemed University), Bhopal 462051 (India); Soni, R.K.; Dutt, Krishna; Singh, Swati [Department of Chemistry, Ch. Charan Singh University, Meerut 250004 (India)

2010-06-15

Polyethylene terephthalate (PET) waste flakes were degraded with aqueous methylamine and aqueous ammonia, respectively at room temperature in the presence and absence of quaternary ammonium salt as a catalyst for different periods of time. The aminolysed and ammonolysed PET samples were investigated for the surface morphology with the help of scanning electron micrograph (SEM). It shows that the semi-crystalline PET waste samples reduce to monodisperse rods before fully degradation to the end products. The presence of the catalyst provides site for degradation of PET waste and enhances the rate of degradation. The SEM shows early developments of fissures in comparison to the one in absence of quaternary ammonium salt used as catalyst.

Scanning electron microscopic study of hazardous waste flakes of polyethylene terephthalate (PET) by aminolysis and ammonolysis

International Nuclear Information System (INIS)

Mittal, Alok; Soni, R.K.; Dutt, Krishna; Singh, Swati

2010-01-01

Polyethylene terephthalate (PET) waste flakes were degraded with aqueous methylamine and aqueous ammonia, respectively at room temperature in the presence and absence of quaternary ammonium salt as a catalyst for different periods of time. The aminolysed and ammonolysed PET samples were investigated for the surface morphology with the help of scanning electron micrograph (SEM). It shows that the semi-crystalline PET waste samples reduce to monodisperse rods before fully degradation to the end products. The presence of the catalyst provides site for degradation of PET waste and enhances the rate of degradation. The SEM shows early developments of fissures in comparison to the one in absence of quaternary ammonium salt used as catalyst.

Performance evaluation of neuro-PET using silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Jung, Jiwoong; Choi, Yong, E-mail: ychoi@sogang.ac.kr; Jung, Jin Ho, E-mail: jinho1115@gmail.com; Kim, Sangsu; Im, Ki Chun

2016-05-21

Recently, we have developed the second prototype Silicon photomultiplier (SiPM) based positron emission tomography (PET) scanner for human brain imaging. The PET system was comprised of detector block which consisted of 4×4 SiPMs and 4×4 Lutetium Yttrium Orthosilicate arrays, charge signal transmission method, high density position decoder circuit and FPGA-embedded ADC boards. The purpose of this study was to evaluate the performance of the newly developed neuro-PET system. The energy resolution, timing resolution, spatial resolution, sensitivity, stability of the photo-peak position and count rate performance were measured. Tomographic image of 3D Hoffman brain phantom was also acquired to evaluate imaging capability of the neuro-PET. The average energy and timing resolutions measured for 511 keV gamma rays were 17±0.1% and 3±0.3 ns, respectively. Spatial resolution and sensitivity at the center of field of view (FOV) were 3.1 mm and 0.8%, respectively. The average scatter fraction was 0.4 with an energy window of 350–650 keV. The maximum true count rate and maximum NECR were measured as 43.3 kcps and 6.5 kcps at an activity concentration of 16.7 kBq/ml and 5.5 kBq/ml, respectively. Long-term stability results show that there was no significant change in the photo-peak position, energy resolution and count rate for 60 days. Phantom imaging studies were performed and they demonstrated the feasibility for high quality brain imaging. The performance tests and imaging results indicate that the newly developed PET is useful for brain imaging studies, if the axial FOV is extended to improve the system sensitivity.

Simultaneous functional imaging using fPET and fMRI

Energy Technology Data Exchange (ETDEWEB)

Villien, Marjorie [CERMEP (France)

2015-05-18

Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

Simultaneous functional imaging using fPET and fMRI

International Nuclear Information System (INIS)

Villien, Marjorie

2015-01-01

Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

Clinical Application of F-18 FDG PET (PET/CT) in Malignancy of Unknown Origin

International Nuclear Information System (INIS)

Kim, Byung Il

2008-01-01

Diagnosis of primary origin site in the management of malignancy of unknown origin (MUO) is the most important issue. According to the histopathologic subtype of primary lesion, specialized treatment can be given and survival gain is expected. F-18 FDG PET (PET/CT) has been estimated as useful in detection of primary lesion with high sensitivity and moderate specificity. F-18 FDG PET (PET/CT) study before conventional studies is also recommended because it has high diagnostic performance compared to conventional studies. Although there has few data, F-18 FDG PET (PET/CT) is expected to be useful in diagnosis of recurrence, restaging, evaluation of treatment effect, considering that PET (PET/CT) has been reported as useful in other malignancies

Small Animal [18F]FDG PET Imaging for Tumor Model Study

International Nuclear Information System (INIS)

Woo, Sang Keun; Kim, Kyeong Min; Cheon, Gi Jeong

2008-01-01

PET allows non-invasive, quantitative and repetitive imaging of biological function in living animals. Small animal PET imaging with [ 18 F]FDG has been successfully applied to investigation of metabolism, receptor, ligand interactions, gene expression, adoptive cell therapy and somatic gene therapy. Experimental condition of animal handling impacts on the biodistribution of [ 18 F]FDG in small animal study. The small animal PET and CT images were registered using the hardware fiducial markers and small animal contour point. Tumor imaging in small animal with small animal [ 18 F]FDG PET should be considered fasting, warming, and isoflurane anesthesia level. Registered imaging with small animal PET and CT image could be useful for the detection of tumor. Small animal experimental condition of animal handling and registration method will be of most importance for small lesion detection of metastases tumor model

Application of PET and PET/CT imaging for cancer screening

International Nuclear Information System (INIS)

Chen Yenkung; Hu Fenglan; Shen Yehyou; Liao, A.C.; Hung, T.Z.; Su, Chentau; Chen Liangkuang

2004-01-01

The aim of this study was to evaluate the potential application of 18F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) and PET/CT for cancer screening in asymptomatic individuals. Methods: The subjects consisted of 3631 physical check up examinees (1947 men, 1684 women; mean age ±SD, 52.1±8.2 y) with non-specific medical histories. Whole-body FDG PET (or PET/CT), ultrasound and tumor markers were performed on all patients. Focal hypermetabolic areas with intensities equal to or exceeding the level of FDG uptake in the brain and bladder were considered abnormal and interpreted as neoplasia. Follow-up periods were longer than one year. Results: Among the 3631 FDG PET (including 1687 PET/CT), ultrasound and tumor markers examinations, malignant tumors were discovered in 47 examinees (1.29%). PET findings were true-positive in 38 of the 47 cancers (80.9%). In addition, 32 of the 47 cancers were performed with the PET-CT scan. PET detected cancer lesions in 28 of the 32 examinees. However, the CT detected cancer lesions in only 15 of 32 examinees. Conclusion: The sensitivity of FDG PET in the detection of a wide variety of cancers is high. Most cancer can be detected with FDG PET in a resectable stage. CT of the PET/CT for localization and characteristics of the lesion shows an increased specificity of the PET scan. Using ultrasound and tumor markers may complement the PET scan in cancer screening for hepatic and urologic neoplasms. (authors)

PET-COMPTON System. Comparative evaluation with PET System using Monte Carlo Simulation

International Nuclear Information System (INIS)

Diaz Garcia, Angelina; Arista Romeu, Eduardo; Abreu Alfonso, Yamiel; Leyva Fabelo, Antonio; Pinnera HernAndez, Ibrahin; Bolannos Perez, Lourdes; Rubio Rodriguez, Juan A.; Perez Morales, Jose M.; Arce Dubois, Pedro; Vela Morales, Oscar; Willmott Zappacosta, Carlos

2012-01-01

Positron Emission Tomography (PET) in small animals has actually achieved spatial resolution round about 1 mm and currently there are under study different approaches to improve this spatial resolution. One of them combines PET technology with Compton Cameras. This paper presents the idea of the so called PET-Compton systems and has included comparative evaluation of spatial resolution and global efficiency in both PET and PET-Compton system by means of Monte Carlo simulations using Geant4 code. Simulation was done on a PET-Compton system made-up of LYSO-LuYAP scintillating detectors of particular small animal PET scanner named Clear-PET and for Compton detectors based on CdZnTe semiconductor. A group of radionuclides that emits a positron (e+) and quantum almost simultaneously and fulfills some selection criteria for their possible use in PET-Compton systems for medical and biological applications were studied under simulation conditions. By means of analytical reconstruction using SSRB (Single Slide Rebinning) method were obtained superior spatial resolution in PET-Compton system for all tested radionuclides (reaching sub-millimeter values of for 22Na source). However this analysis done by simulation have shown limited global efficiency values in PET-Compton system (in the order of 10 -5 -10 -6 %) instead of values around 5*10 -1 % that have been achieved in PET system. (author)

Pre and post operative evaluation of the perfusion reserve by acetazolamide 99mTc-HMPAO SPECT in patients with chronic occlusive cerebral arteries. A comparative study with PET

International Nuclear Information System (INIS)

Kuwabara, Yasuo; Ichiya, Yuichi; Sasaki, Masayuki; Akashi, Yuko; Yoshida, Tsuyoshi; Fukumura, Toshimitsu; Masuda, Kouji; Fujii, Kiyotaka; Fukui, Masashi

1994-01-01

We studied the pre and post-operative perfusion reserve using Diamox 99m Tc-HMPAO SPECT in 7 patients with chronic occlusive cerebral arteries and then compared the results with PET. STAMCA anastomosis was performed on 5 patients, while a carotid endarterectomy was done on 2 patients. The cerebral blood flow, the vascular response to CO 2 or Diamox, the oxygen extraction fraction and transit time (CBV/CBF) were measured by PET. In the pre-operative state, the visual evaluations for hypoperfusion area at rest agreed in 5 out of 7 patients in HMPAO SPECT and PET studies. In the remaining 2 patients, hypoperfusion areas were only detected in the PET study. The pre-operative evaluation of perfusion reserve agreed in 2 patients. In the remaining 5 patients, 3 patients showed definite positive (++) in PET and positive (+) in HMPAO SPECT, and one patient showed positive (+) in PET and negative (-) in HMPAO SPECT. The post-operative change of hypoperfusion areas well agreed in HMPAO SPECT and PET studies. However, the change of perfusion reserve was underestimated in HMPAO SPECT compared with PET. In the semiquantitative and quantitative analyses, the count rate ratios (affected/unaffected side) in HMPAO SPECT were apparently higher than those of CBF in PET. The postoperative change of the count rate ratios in HMPAO SPECT were smaller than those of CBF in PET. There was no significant correlation between the change in the ratio of the HMPAO SPECT after the administration of Diamox and the oxygen extraction fraction, and it was thus thought to be impossible to predict the areas with an increased oxygen extraction fraction. Thus, Diamox HMPAO SPECT may underestimate the areas of hypoperfusion or decrease in perfusion reserve when compared with PET. We should consider these limitations in the evaluation of pre and post operative cerebral hemodynamics. (author)

Does Antibiotic Treatment Affect the Diagnostic Accuracy of 18F-FDG PET/CT Studies in Patients with Suspected Infectious Processes?

Science.gov (United States)

Kagna, Olga; Kurash, Marina; Ghanem-Zoubi, Nesrin; Keidar, Zohar; Israel, Ora

2017-11-01

18 F-FDG PET/CT plays a significant role in the assessment of various infectious processes. Patients with suspected or known sites of infection are often referred for 18 F-FDG imaging while already receiving antibiotic treatment. The current study assessed whether antibiotic therapy affected the detectability rate of infectious processes by 18 F-FDG PET/CT. Methods: A 5-y retrospective study of all adult patients who underwent 18 F-FDG PET/CT in search of a focal source of infection was performed. The presence, duration, and appropriateness of antibiotic treatment before 18 F-FDG imaging were recorded. Diagnosis of an infectious process was based on microbiologic or pathologic data as well as on clinical and radiologic follow-up. Results: Two hundred seventeen patients underwent 243 PET/CT studies in search of a focal source of infection and were included in the study. Sixty-seven studies were excluded from further analysis because of a final noninfectious etiology or lack of further follow-up or details regarding the antibiotic treatment. The final study population included 176 18 F-FDG PET/CT studies in 153 patients (107 men, 46 women; age range, 18-86 y). One hundred nineteen studies (68%) were performed in patients receiving antibiotic therapy for a range of 1-73 d. A diagnosis of infection was made in 107 true-positive cases (61%), including 63 studies (59%) in patients receiving appropriate antibiotic therapy started before the performance of the 18 F-FDG PET/CT study. There were 52 true-negative (29%) and 17 false-positive (10%) 18 F-FDG PET/CT studies. No false-negative results were found. Conclusion: 18 F-FDG PET/CT correctly identified foci of increased uptake compatible with infection in most patients, including all patients receiving appropriate antimicrobial therapy, with no false-negative cases. On the basis of the current study results, the administration of antibiotics appears to have no clinically significant impact on the diagnostic accuracy of 18

Parametric study on the steam reforming of phenol-PET solution to hydrogen production over Ni promoted on Al_2O_3-La_2O_3 catalyst

International Nuclear Information System (INIS)

Nabgan, Bahador; Nabgan, Walid; Tuan Abdullah, Tuan Amran; Tahir, Muhammad; Gambo, Yahya; Ibrahim, Maryam; Syie Luing, Wong

2017-01-01

Highlights: • Parametric study of H_2 production from phenol-PET steam reforming was studied. • Optimised conditions were 800 °C, 0.10 ml/min feed flow rate, and 7% PET. • High amount of aliphatic branched-chains and cyclic compounds were produced. • PET was efficiently converted to hydrogen and valuable fuels at optimized condition. • Significant influence resulted for all the main independent factors. - Abstract: Production of hydrogen from plastic waste could be a prospective key to the ecological problems resulted from waste. To further explore the process, a 32-runs parametric study on the steam reforming of Polyethylene terephthalate (PET) dissolved in phenol was conducted in a fixed bed reactor using Ni over La_2O_3-Al_2O_3 support. The five factors studied were temperature (A), feed flow rate (B), mass flow (C), phenol concentration (D), and concentration of PET solution (E), whereas the responses were phenol conversion (Y_1) and hydrogen selectivity (Y_2). From the result, it was observed that significant influence resulted for all the main independent variables on the dependent variable of Y_1 and Y_2 with the range of 47.24–97.6% and 49–70.96%, respectively. Moreover, the Y_1 and Y_2 responses have influenced by some interaction variables like AC, CD, CE, ACE, and BCE. As evident from the design, initial variables such as 800 °C, 0.10 ml/min feed flow rate, 10 SCCM mass flow, 10 wt.% of phenol in the feed, and 7% PET concentration were the best preliminary conditions that formed maximum Y_1 (94%) and Y_2 (71%) responses. However, analyses on the product composition revealed that high amount of aliphatic branched-chains along with moderate amount of cyclic compounds were produced from steam reforming of PET-phenol. Due to the short retention time of the compounds on the catalysts bed, the aromatization of PET cracking products was small.

An update on technical and methodological aspects for cardiac PET applications

International Nuclear Information System (INIS)

PRESOTTO, Luca; BUSNARDO, Elena; GIANOLLI, Luigi; BETTINARDI, Valentino

2016-01-01

Positron emission tomography (PET) is indicated for a large number of cardiac diseases: perfusion and viability studies are commonly used to evaluate coronary artery disease; PET can also be used to assess sarcoidosis and endocarditis, as well as to investigate amyloidosis. Furthermore, a hot topic for research is plaque characterization. Most of these studies are technically very challenging. High count rates and short acquisition times characterize perfusion scans while very small targets have to be imaged in inflammation/infection and plaques examinations. Furthermore, cardiac PET suffers from respiratory and cardiac motion blur. Each type of studies has specific requirements from the technical and methodological point of view, thus PET systems with overall high performances are required. Furthermore, in the era of hybrid PET/computed tomography (CT) and PET/Magnetic Resonance Imaging (MRI) systems, the combination of complementary functional and anatomical information can be used to improve diagnosis and prognosis. Moreover, PET images can be qualitatively and quantitatively improved exploiting information from the other modality, using advanced algorithms. In this review we will report the latest technological and methodological innovations for PET cardiac applications, with particular reference to the state of the art of the hybrid PET/CT and PET/MRI. We will also report the most recent advancements in software, from reconstruction algorithms to image processing and analysis programs.

Positron emission tomography (PET) studies of dopaminergic/cholinergic interactions in the baboon brain

International Nuclear Information System (INIS)

Dewey, S.L.; Brodie, J.D.; Fowler, J.S.; MacGregor, R.R.; Schlyer, D.J.; King, P.T.; Alexoff, D.L.; Volkow, N.D.; Shiue, C.Y.; Wolf, A.P.

1990-01-01

Interactions between the dopaminergic D2 receptor system and the muscarinic cholinergic system in the corpus striatum of adult female baboons (Papio anubis) were examined using positron emission tomography (PET) combined with [18F]N-methylspiroperidol [( 18F]NMSP) (to probe D2 receptor availability) and [N-11C-methyl]benztropine (to probe muscarinic cholinergic receptor availability). Pretreatment with benztropine, a long-lasting anticholinergic drug, bilaterally reduced the incorporation of radioactivity in the corpus striatum but did not alter that observed in the cerebellum or the rate of metabolism of [18F]NMSP in plasma. Pretreatment with unlabelled NMSP, a potent dopaminergic antagonist, reduced the incorporation of [N-11C-methyl]benztropine in all brain regions, with the greatest effect being in the corpus striatum greater than cortex greater than thalamus greater than cerebellum, but did not alter the rate of metabolism of the labelled benztropine in the plasma. These reductions in the incorporation of either [18F]NMSP or [N-11C-methyl]benztropine exceeded the normal variation in tracer incorporation in repeated studies in the same animal. This study demonstrates that PET can be used as a tool for investigating interactions between neurochemically different yet functionally linked neurotransmitters systems in vivo and provides insight into the consequences of multiple pharmacologic administration

Evaluation of the PET component of simultaneous [18F]choline PET/MRI in prostate cancer: comparison with [18F]choline PET/CT

International Nuclear Information System (INIS)

Wetter, Axel; Lipponer, Christine; Nensa, Felix; Altenbernd, Jens-Christian; Schlosser, Thomas; Lauenstein, Thomas; Heusch, Philipp; Ruebben, Herbert; Bockisch, Andreas; Poeppel, Thorsten; Nagarajah, James

2014-01-01

The aim of this study was to evaluate the positron emission tomography (PET) component of [ 18 F]choline PET/MRI and compare it with the PET component of [ 18 F]choline PET/CT in patients with histologically proven prostate cancer and suspected recurrent prostate cancer. Thirty-six patients were examined with simultaneous [ 18 F]choline PET/MRI following combined [ 18 F]choline PET/CT. Fifty-eight PET-positive lesions in PET/CT and PET/MRI were evaluated by measuring the maximum and mean standardized uptake values (SUV max and SUV mean ) using volume of interest (VOI) analysis. A scoring system was applied to determine the quality of the PET images of both PET/CT and PET/MRI. Agreement between PET/CT and PET/MRI regarding SUV max and SUV mean was tested using Pearson's product-moment correlation and Bland-Altman analysis. All PET-positive lesions that were visible on PET/CT were also detectable on PET/MRI. The quality of the PET images was comparable in both groups. Median SUV max and SUV mean of all lesions were significantly lower in PET/MRI than in PET/CT (5.2 vs 6.1, p max of PET/CT and PET/MRI (R = 0.86, p mean of PET/CT and PET/MRI (R = 0.81, p max of PET/CT vs PET/MRI and -1.12 to +2.23 between SUV mean of PET/CT vs PET/MRI. PET image quality of PET/MRI was comparable to that of PET/CT. A highly significant correlation between SUV max and SUV mean was found. Both SUV max and SUV mean were significantly lower in [ 18 F]choline PET/MRI than in [ 18 F]choline PET/CT. Differences of SUV max and SUV mean might be caused by different techniques of attenuation correction. Furthermore, differences in biodistribution and biokinetics of [ 18 F]choline between the subsequent examinations and in the respective organ systems have to be taken into account. (orig.)

Direct comparison of [18F]FDG PET/CT with PET alone and with side-by-side PET and CT in patients with malignant melanoma

International Nuclear Information System (INIS)

Mottaghy, Felix M.; Wohlfart, Petra; Blumstein, Norbert M.; Neumaier, Bernd; Glatting, Gerhard; Buck, Andreas K.; Reske, Sven N.; Sunderkoetter, Cord; Schubert, Roland; Oezdemir, Cueneyt; Scharfetter-Kochanek, Karin

2007-01-01

The purpose of this retrospective, blinded study was to evaluate the additional value of [ 18 F]FDG PET/CT in comparison with PET alone and with side-by-side PET and CT in patients with malignant melanoma (MM). A total of 127 consecutive studies of patients with known MM referred for a whole-body PET/CT examination were included in this study. PET alone, side-by-side PET and CT and integrated PET/CT study were independently and separately interpreted without awareness of the clinical information. One score each was applied for certainty of lesion localisation and for certainty of lesion characterisation. Verification of the findings was subsequently performed using all available clinical, pathological (n = 30) and follow-up information. The number of lesions with an uncertain localisation was significantly (p 18 F]FDG. (orig.)

Detection and quantification of focal uptake in head and neck tumours: {sup 18}F-FDG PET/MR versus PET/CT

Energy Technology Data Exchange (ETDEWEB)

Varoquaux, Arthur; Rager, Olivier; Ratib, Osman; Becker, Christoph D.; Zaidi, Habib; Becker, Minerva [Geneva University Hospital, Department of Imaging, Divisions of Radiology and Nuclear Medicine, Geneva 14 (Switzerland); Poncet, Antoine [Geneva University Hospital, Center for Clinical Research, Geneva (Switzerland); Delattre, Benedicte M.A. [Geneva University Hospital, Department of Imaging, Divisions of Radiology and Nuclear Medicine, Geneva 14 (Switzerland); Philips Healthcare AG, Nuclear Medicine Division, Gland (Switzerland); Dulguerov, Pavel; Dulguerov, Nicolas [Geneva University Hospital, Clinic of Otorhinolaryngology Head and Neck Surgery, Geneva (Switzerland)

2014-03-15

Our objectives were to assess the quality of PET images and coregistered anatomic images obtained with PET/MR, to evaluate the detection of focal uptake and SUV, and to compare these findings with those of PET/CT in patients with head and neck tumours. The study group comprised 32 consecutive patients with malignant head and neck tumours who underwent whole-body {sup 18}F-FDG PET/MR and PET/CT. PET images were reconstructed using the attenuation correction sequence for PET/MR and CT for PET/CT. Two experienced observers evaluated the anonymized data. They evaluated image and fusion quality, lesion conspicuity, anatomic location, number and size of categorized (benign versus assumed malignant) lesions with focal uptake. Region of interest (ROI) analysis was performed to determine SUVs of lesions and organs for both modalities. Statistical analysis considered data clustering due to multiple lesions per patient. PET/MR coregistration and image fusion was feasible in all patients. The analysis included 66 malignant lesions (tumours, metastatic lymph nodes and distant metastases), 136 benign lesions and 470 organ ROIs. There was no statistically significant difference between PET/MR and PET/CT regarding rating scores for image quality, fusion quality, lesion conspicuity or anatomic location, number of detected lesions and number of patients with and without malignant lesions. A high correlation was observed for SUV{sub mean} and SUV{sub max} measured on PET/MR and PET/CT for malignant lesions, benign lesions and organs (ρ = 0.787 to 0.877, p < 0.001). SUV{sub mean} and SUV{sub max} measured on PET/MR were significantly lower than on PET/CT for malignant tumours, metastatic neck nodes, benign lesions, bone marrow, and liver (p < 0.05). The main factor affecting the difference between SUVs in malignant lesions was tumour size (p < 0.01). In patients with head and neck tumours, PET/MR showed equivalent performance to PET/CT in terms of qualitative results. Comparison of

Childhood Attachment to Pets: Associations between Pet Attachment, Attitudes to Animals, Compassion, and Humane Behaviour

Directory of Open Access Journals (Sweden)

Roxanne D. Hawkins

2017-05-01

Full Text Available Attachment to pets has an important role in children’s social, emotional, and cognitive development, mental health, well-being, and quality of life. This study examined associations between childhood attachment to pets and caring and friendship behaviour, compassion, and attitudes towards animals. This study also examined socio-demographic differences, particularly pet ownership and pet type. A self-report survey of over one thousand 7 to 12 year-olds in Scotland, UK, revealed that the majority of children are strongly attached to their pets, but attachment scores differ depending on pet type and child gender. Analysis revealed that attachment to pets is facilitated by compassion and caring and pet-directed friendship behaviours and that attachment to pets significantly predicts positive attitudes towards animals. The findings have implications for the promotion of prosocial and humane behaviour. Encouraging children to participate in pet care behaviour may promote attachment between children and their pet, which in turn may have a range of positive outcomes for both children (such as reduced aggression, better well-being, and quality of life and pets (such as humane treatment. This study enhances our understanding of childhood pet attachment and has implications for humane education and promoting secure emotional attachments in childhood.

Quantitative simultaneous PET-MR imaging

Science.gov (United States)

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

2014-06-01

Whole-body PET is currently limited by the degradation due to patient motion. Respiratory motion degrades imaging studies of the abdomen. Similarly, both respiratory and cardiac motions significantly hamper the assessment of myocardial ischemia and/or metabolism in perfusion and viability cardiac PET studies. Based on simultaneous PET-MR, we have developed robust and accurate MRI methods allowing the tracking and measurement of both respiratory and cardiac motions during abdominal or cardiac studies. Our list-mode iterative PET reconstruction framework incorporates the measured motion fields into PET emission system matrix as well as the time-dependent PET attenuation map and the position dependent point spread function. Our method significantly enhances the PET image quality as compared to conventional methods.

[Study of patients with prolonged fever with (18)F-FDG PET/CT].

Science.gov (United States)

Moragas, M; Cozar, M Puig; Buxeda, M; Soler, M; Riera, E; García, J R

2015-01-01

To review the findings on (18)F-FDG PET-CT in patients with fever of unknown origin lasting more than 7 days. This retrospective descriptive observational study included 93 (18)F-FDG PET-CT studies to detect a fever-causing focus done at three nuclear medicine centers from October 2006 through February 2014. A nuclear medicine specialist and a radiologist reviewed the images for foci of pathological uptake; another specialist's opinion resolved discrepancies. The findings on (18)F-FDG PET-CT studies were checked against clinical and/or histological findings. Abnormal (18)F-FDG uptake on PET-CT that could explain the cause of the fever was found in 52 (56%) of the 93 studies, and the cause of the fever was confirmed in 50 of these 52 studies. In the 50 cases in which the cause of the fever was confirmed, infection was the most common cause (54%), followed by noninfectious inflammatory disease (28%) and tumors (18%). (18)F-FDG PET-CT is useful in diagnosing the cause of prolonged febrile illness, so it might be practical to use it earlier in the diagnostic process. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Evaluation of in vivo quantification accuracy of the Ingenuity-TF PET/MR.

Science.gov (United States)

Maus, Jens; Schramm, Georg; Hofheinz, Frank; Oehme, Liane; Lougovski, Alexandr; Petr, Jan; Platzek, Ivan; Beuthien-Baumann, Bettina; Steinbach, Jörg; Kotzerke, Jörg; van den Hoff, Jörg

2015-10-01

The quantitative accuracy of standardized uptake values (SUVs) and tracer kinetic uptake parameters in patient investigations strongly depends on accurate determination of regional activity concentrations in positron emission tomography (PET) data. This determination rests on the assumption that the given scanner calibration is valid in vivo. In a previous study, we introduced a method to test this assumption. This method allows to identify discrepancies in quantitative accuracy in vivo by comparison of activity concentrations of urine samples measured in a well-counter with activity concentrations extracted from PET images of the bladder. In the present study, we have applied this method to the Philips Ingenuity-TF PET/MR since at the present stage, absolute quantitative accuracy of combined PET/MR systems is still under investigation. Twenty one clinical whole-body F18-FDG scans were included in this study. The bladder region was imaged as the last bed position and urine samples were collected afterward. PET images were reconstructed including MR-based attenuation correction with and without truncation compensation and 3D regions-of-interest (ROIs) of the bladder were delineated by three observers. To exclude partial volume effects, ROIs were concentrically shrunk by 8-10 mm. Then, activity concentrations were determined in the PET images for the bladder and for the urine by measuring the samples in a calibrated well-counter. In addition, linearity measurements of SUV vs singles rate and measurements of the stability of the coincidence rate of "true" events of the PET/MR system were performed over a period of 4 months. The measured in vivo activity concentrations were significantly lower in PET/MR than in the well-counter with a ratio of the former to the latter of 0.756 ± 0.060 (mean ± std. dev.), a range of 0.604-0.858, and a P value of 3.9 ⋅ 10(-14). While the stability measurements of the coincidence rate of "true" events showed no relevant deviation over

Evaluation of in vivo quantification accuracy of the Ingenuity-TF PET/MR

Energy Technology Data Exchange (ETDEWEB)

Maus, Jens, E-mail: j.maus@hzdr.de; Schramm, Georg; Hofheinz, Frank; Lougovski, Alexandr; Petr, Jan; Steinbach, Jörg [PET Center, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Oehme, Liane; Beuthien-Baumann, Bettina; Kotzerke, Jörg [Department of Nuclear Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); Platzek, Ivan [Department of Radiology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); Hoff, Jörg van den [PET Center, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany and Department of Nuclear Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany)

2015-10-15

Purpose: The quantitative accuracy of standardized uptake values (SUVs) and tracer kinetic uptake parameters in patient investigations strongly depends on accurate determination of regional activity concentrations in positron emission tomography (PET) data. This determination rests on the assumption that the given scanner calibration is valid in vivo. In a previous study, we introduced a method to test this assumption. This method allows to identify discrepancies in quantitative accuracy in vivo by comparison of activity concentrations of urine samples measured in a well-counter with activity concentrations extracted from PET images of the bladder. In the present study, we have applied this method to the Philips Ingenuity-TF PET/MR since at the present stage, absolute quantitative accuracy of combined PET/MR systems is still under investigation. Methods: Twenty one clinical whole-body F18-FDG scans were included in this study. The bladder region was imaged as the last bed position and urine samples were collected afterward. PET images were reconstructed including MR-based attenuation correction with and without truncation compensation and 3D regions-of-interest (ROIs) of the bladder were delineated by three observers. To exclude partial volume effects, ROIs were concentrically shrunk by 8–10 mm. Then, activity concentrations were determined in the PET images for the bladder and for the urine by measuring the samples in a calibrated well-counter. In addition, linearity measurements of SUV vs singles rate and measurements of the stability of the coincidence rate of “true” events of the PET/MR system were performed over a period of 4 months. Results: The measured in vivo activity concentrations were significantly lower in PET/MR than in the well-counter with a ratio of the former to the latter of 0.756 ± 0.060 (mean ± std. dev.), a range of 0.604–0.858, and a P value of 3.9 ⋅ 10{sup −14}. While the stability measurements of the coincidence rate of �

Characterization studies of Silicon Photomultipliers and crystals matrices for a novel time of flight PET detector

CERN Document Server

Auffray, Etiennette; Cortinovis, Daniele; Doroud, Katayoun; Garutti, Erika; Lecoq, Paul; Liu, Zheng; Martinez, Rosana; Paganoni, Marco; Pizzichemi, Marco; Silenzi, Alessandro; Xu, Chen; Zvolský, Milan

2015-01-01

This paper describes the characterization of crystal matrices and silicon photomultiplier arrays for a novel Positron Emission Tomography (PET) detector, namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in a novel multimodal device, capable to support the development of new biomarkers for prostate and pancreatic tumors. The detector consists in two parts: a PET head mounted on an ultrasound probe and an external PET plate. The challenging goal of 1 mm spatial resolution for the PET image requires a detector with small crystal size, and therefore high channel density: 4096 LYSO crystals individually readout by Silicon Photomultipliers (SiPM) make up the external plate. The quality and properties of these components must be assessed before the assembly. The dark count rate, gain, breakdown voltage and correlated noise of the SiPMs are measured, while the LYSO crystals are evaluated in terms of light yield and en...

Development of PET insert for simultaneous PET/MR imaging of human brain

Energy Technology Data Exchange (ETDEWEB)

Jung, Jiwoong; Choi, Yong; Jung, Jin Ho; Kim, Sangsu; Im, Ki Chun; Lim, Hyun Keong [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Oh, Changheun; Park, HyunWook; Cho, Gyuseong [Departments of Electrical Engineering and Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

2014-07-29

Recently, there has been great interest on the development of combined PET/MR, which is a useful tool for both functional and anatomic imaging. The purpose of this study was to develop a MR compatible PET insert for simultaneous PET and MR imaging of human brain and to evaluate the performance of the hybrid PET-MRI. The PET insert consisted of 18 detector blocks arranged in a ring of 390 mm diameter with 60 mm axial FOV. Each detector block was composed of 4 × 4 matrix of detector modules, each of which consisted of a 4 × 4 array LYSO coupled to a 4 × 4 GAPD array. The PET gantry was shielded with gold-plated conductive fabric tapes. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuits (PDCs) and then transferred to FPGA-embedded DAQ modules. The PDCs and DAQ modules were enclosed in an aluminum box and located at the rear of the MR bore inside MRI room. 3-T human MRIs of two different vendors were used to evaluate the MR compatibility of developed PET insert. No significant changes of the PET performance and the homogeneity of MR images caused by the non-compatibility of PET-MRI were observed with the 2 different MRIs. The signal intensities of MR images were slightly degraded (<3.6%) with the both MRI systems. The difference between independently and simultaneously acquired PET images of brain phantom was negligibly small (<4.3%). High quality simultaneous brain PET and MRI of 3 normal volunteers were successfully acquired. Experimental results indicate that the high performance compact and lightweight PET insert for hybrid PET/MRI, which could be utilized with the MRI from various manufactures, can be developed using GAPD arrays and charge signal transmission method proposed in this study.

FDG-PET and FDG-PET/CT for therapy monitoring and restaging in malignant lymphoma

International Nuclear Information System (INIS)

Mottaghy, F.M.; Krause, B.J.

2003-01-01

F-18-fluorodeoxyglucose (FDG) PET allows to assess residual masses in patients with malignant lymphoma differentiating vital tumor from scar tissue. This approach is not applicable with conventional imaging methods (CDM) such as CT or MRI. On the other hand circumscribed results often cannot be definitely allocated in PET, therefore the combined morphological-biochemical approach using the now available PET/CT systems promises to be a pathbreaking technical progress. There is no doubt that stand alone PET is superior to CDM differentiating residual scar tissue from vital tumor as has been shown in 15 recently published studies. The median sensitivity for detecting active disease with FDG PET across the studies was 91%; the corresponding specificity was 89%. As a result FDG PET had a high negative predictive value of 94%. In contrast, specificity and positive predictive value (PPV) of CDM in the 9 studies were a direct comparison was available were low (31% and 46%, one study 82%). PET positive residual masses were associated with a progression-free survival of 0 - 55%. Only a few studies have included FDG-PET in therapy response monitoring studies, however also these results are promising. At the moment FDG-PET seems to be the best possibility to characterize and qualitatively visualize vitality of tumor masses and also hold promises for efficient therapy response monitoring in patients with malignant lymphoma. Therefore it should be included in standard diagnostic protocols in lymphoma patients. The combined PET/CT has to be ranked superior to conventional PET studies as in many cases the combined structural and functional imaging brings a clearer diagnostic statement. (orig.) [de

Approaches using molecular imaging technology - use of PET in clinical microdose studies§

OpenAIRE

Wagner, Claudia C.; Langer, Oliver

2011-01-01

Positron emission tomography (PET) imaging uses minute amounts of radiolabeled drug tracers and thereby meets the criteria for clinical microdose studies. The advantage of PET, when compared to other analytical methods used in microdose studies, is that the pharmacokinetics (PK) of a drug can be determined in the tissue targeted for drug treatment. PET microdosing already offers interesting applications in clinical oncology and in the development of central nervous system pharmaceuticals and ...

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis

International Nuclear Information System (INIS)

Jin, H.; Yuan, L.; Li, C.; Kan, Y.; Yang, J.; Hao, R.

2014-01-01

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection. Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis. In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis.

Science.gov (United States)

Jin, H; Yuan, L; Li, C; Kan, Y; Hao, R; Yang, J

2014-03-01

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection. Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis. In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

Performance characteristics of 3D GSO PET/CT scanner (Philips GEMINI PET/CT)

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Lee, Byeong Il; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul

2004-01-01

from the center. Scatter fraction was 40.6%, and peak true count rate and NECR were 88.9 kcps 12.9 kBq/mL and 34.3 kcps 8.84 kBq/mL. These characteristics are better than that of ECAT EXACT PET scanner with BGO crystal. The results of this field test demonstrate high resolution, sensitivity and count rate performance of the 3D PET/CT scanner with GSO crystal. The data provided here will be useful for the comparative study with other 3D PET/CT scanners using BGO or LSO crystals

Combined FDG-PET/CT for the detection of unknown primary tumors: systematic review and meta-analysis

International Nuclear Information System (INIS)

Kwee, Thomas C.; Kwee, Robert M.

2009-01-01

The aim of this study was to systematically review and meta-analyze published data on the diagnostic performance of combined 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the detection of primary tumors in patients with cancer of unknown primary (CUP). A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Methodological quality of the included studies was assessed. Reported detection rates, sensitivities and specificities were meta-analyzed. Subgroup analyses were performed if results of individual studies were heterogeneous. The 11 included studies, comprising a total sample size of 433 patients with CUP, had moderate methodological quality. Overall primary tumor detection rate, pooled sensitivity and specificity of FDG-PET/CT were 37%, 84% (95% CI 78-88%) and 84% (95% CI 78-89%), respectively. Sensitivity was heterogeneous across studies (P = 0.0001), whereas specificity was homogeneous across studies (P = 0.2114). Completeness of diagnostic workup before FDG-PET/CT, location of metastases of unknown primary, administration of CT contrast agents, type of FDG-PET/CT images evaluated and way of FDG-PET/CT review did not significantly influence diagnostic performance. In conclusion, FDG-PET/CT can be a useful method for unknown primary tumor detection. Future studies are required to prove the assumed advantage of FDG-PET/CT over FDG-PET alone and to further explore causes of heterogeneity. (orig.)

A phantom study of tumor contouring on PET imaging

International Nuclear Information System (INIS)

Chen Song; Li Xuena; Li Yaming; Yin Yafu; Li Na; Han Chunqi

2010-01-01

Objective: To explore an algorithm to define the threshold value for tumor contouring on 18 F-fluorodeoxyglucose (FDG) PET imaging. Methods: A National Electrical Manufacturing Association (NEMA)NU 2 1994 PET phantom with 5 spheres of different diameters were filled with 18 F-FDG. Seven different sphere-to-background ratios were obtained and the phantom was scanned by Discovery LS 4. For each sphere-to-background ratio, the maximum standardized uptake value (SUV max ) of each sphere, the SUV of the border of each sphere (SUV border ), the mean SUV of a 1 cm region of background (SUV bg ) and the diameter (D) of each sphere were measured. SPSS 13.0 software was used for curve fitting and regression analysis to obtain the threshold algorithm. The calculated thresholds were applied to delineate 29 pathologically confirmed lung cancer lesions on PET images and the obtained volumes were compared with the volumes contoured on CT images in lung window. Results: The algorithm for defining contour threshold is TH% = 33.1% + 46.8% SUV bg /SUV max + 13.9%/D (r = 0.994) by phantom studies. For 29 lung cancer lesions, the average gross tumor volumes (GTV) delineated on PET and CT are (7.36±1.62) ml and (8.31±2.05) ml, respectively (t = -1.26, P>0.05). Conclusion: The proposed threshold algorithm for tumor contouring on PET image could provide comparable GTV with CT. (authors)

The clinical impact of PET scanning in patients with melanoma: A prospective study

International Nuclear Information System (INIS)

Kalff, V.; Hicks, R.J.; Binns, D.S.; Henderson, M.A.; Ainslie, J.; Jenner, D.A.

1998-01-01

Full text: Small series have shown that PET scanning using F-18 fluorodeoxyglucose (FDG), can quite accurately stage patients melanoma. At this Institute these patients are only sent for PET imaging if they have high risk melanomas ( >3 Clarke's grade primaries) or there remains any significant doubt as to their clinical staging or management after the completion of conventional screening. This prospective study examines how PET scan findings influenced the clinical management decisions in 53 patients (29 males, mean age 54±13 yrs: range 31-81 yrs) Referring doctors were asked to indicate reason for the PET scan, stage their patients on the basis of all their current investigations, and to indicate their management plans prior to PET scanning. Follow-up of subsequent patient management at 2-4 weeks post PET scan was then obtained and compared to pre PET plans. PET was used to stage 26 patients, restage 17, follow-up 5, assess recurrence in 3, and other in 2 patients. To date follow-up has shown that in 32/49 (65%) patients PET was used to triage patients to locoregional surgery (10 patients), radical radiotherapy (5 patients), or to continuing follow-up only (17 patients). Three further high risk patients with negative PET scans had sentinel mode biopsy. In only 13 patients was management already determined, with planned treatment being changed in 6. Four patients have not had their post PET scan review yet. To date proven false negative PET scans have occurred in 3 cases, 2 sentinel node biopsies showed microscopic disease, and one scan incorrectly labelled gall-bladder melanoma as hydro-nephrotic kidney. Interestingly in 3 cases, PET discovered other unsuspected tumours (rectum x 2, plasmacytoma). PET scanning has been incorporated into routine management to triage most high risk patients, but it still alters interventions in half of those patients where management has already been planned. PET clearly misses small volume disease, the importance of which is

Atmospheric tracer study of the emissions from the University of Michigan Cyclotron/PET Facility

International Nuclear Information System (INIS)

Scofield, P.A.

1986-01-01

The University of Michigan (U of M) Cyclotron/Positron Emission Tomography (PET) facility consists of a cyclotron (Model CS-30, The Cyclotron Corporation), radiochemistry laboratory, and Pet scanner. Accelerator-produced radioactive materials, such as, carbon-11 and oxygen-15 are typically emitted from the Cyclotron/PET facility through short stacks located on the roof. This project studied the dispersion of emissions from the facility within the medical complex. To achieve this purpose, the research project had three phases: a physical modeling study; a preliminary field smoke release study; and, a field study using a tracer gas to simulate emission dispersion from the U of M Cyclotron/PET facility vault stack. The objective was to determine normalized concentrations, under selected wind directions and speeds, for use in establishing radionuclide concentrations at the air intakes of the Cyclotron/PET facility and surrounding buildings and at selected ground-level locations

Cost-effectiveness of PET and PET/Computed Tomography

DEFF Research Database (Denmark)

Gerke, Oke; Hermansson, Ronnie; Hess, Søren

2015-01-01

measure by means of incremental cost-effectiveness ratios when considering the replacement of the standard regimen by a new diagnostic procedure. This article discusses economic assessments of PET and PET/computed tomography reported until mid-July 2014. Forty-seven studies on cancer and noncancer...

Solid state polymerization: its action on thermal and rheological properties of PET/PC reactive blends

Directory of Open Access Journals (Sweden)

Luis C. Mendes

2013-01-01

Full Text Available The solid state polymerization (SSP of PET/PC reactive extrusion blends - with and without cobalt catalyst - at different polymer ratios was studied. Thermal and rheological evaluations were performed. DSC results showed changes in the PET's Tg, Tch, Tm and Xc.. The melt flow rate (MFR decreased for PET and the blends. The intrinsic viscosity increased. The variation in calorimetric and rheological properties might be attributed to the PET's chain extension reactions - esterification and transesterification. These reactions led to an increase in the PET's molar mass, consequently shifting the PET's Tg to lower temperature and PET's crystallization, besides reducing the blend miscibility and flowability.

Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

Science.gov (United States)

Rakvongthai, Yothin; El Fakhri, Georges

2017-07-01

Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

FDG PET/CT and Mediastinal Nodal Metastasis Detection in Stage T1 Non-Small Cell Lung Cancer: Prognostic Implications

International Nuclear Information System (INIS)

Shin, Kyung Min; Lee, Kyung Soo; Shim, Young Mog; Kim, Jhin Gook; Kim, Byung Tae; Kwon, O Jung; Park, Keun Chil

2008-01-01

We aimed to compare the prognoses of patients with pathologically true negative (P-TN) N2 and PET/CT false negative (FN) results in stage T1 nonsmall cell lung cancer (NSCLC). Our institutional review board approved this retrospective study with a waiver of informed consent. The study included 184 patients (124 men and 60 women; mean age, 59 years) with stage T1 NSCLC who underwent an integrated PET/CT and surgery. After estimating the efficacy of PET/CT for detecting N2 disease, we determined and compared disease-free survival (DFS) rates in three groups (P-TN [n = 161], PET/CT FN [n = 12], and PET/CT true positive [TP, n = 11]) using the Kaplan-Meier analysis and log-rank test. Pathologic N2 disease was observed in 23 (12%) patients. PET/CT had an N2 disease detection sensitivity of 48% (11 of 23 patients), a specificity of 95% (153 of 161), and an accuracy of 89% (164 of 184). The 3-year DFS rate in the PET/CT FN group (31%, 95% confidence interval [CI]; 13.6-48.0%) was similar to that of the TP group (16%, 95% CI; 1.7-29.5%) (p = 0.649), but both groups had significantly shorter DFS rates than the P-TN group (77%, 95% CI; 72.0- 81.2%) (p < 0.001). The PET/CT shows a high specificity, but low sensitivity for detecting N2 disease in stage T1 NSCLC. Patients with PET/CT FN N2 disease have survival rates similar to PET/CT TP N2 disease patients, which are both substantially shorter than the survival rate of P-TN patients

Added Diagnostic Value of 11C-PiB-PET in Memory Clinic Patients with Uncertain Diagnosis

Directory of Open Access Journals (Sweden)

K.S. Frederiksen

2012-12-01

Full Text Available Introduction: The added diagnostic value of 11C-PiB-PET for the assessment of the accumulation of cortical beta-amyloid in memory clinic patients with uncertain diagnosis remains undetermined. Methods: All patients who underwent PiB-PET at the Copenhagen Memory Clinic between March 2008 and November 2011 were included in this uncontrolled, retrospective study. The standard diagnostic evaluation program included physical and neurological examination, cognitive and functional assessment, a cranial CT or MRI, functional imaging and cerebrospinal fluid sampling. Based on anonymized case reports, three experienced clinicians reached a consensus diagnosis and rated their confidence in the diagnosis before and after disclosure of PiB-PET ratings. PiB-PET scans were rated as either positive or negative. Results: A total of 57 patients (17 females, 30 males; age 65.7 years, range 44.2–82.6 were included in the study. Twenty-seven had a positive PiB-PET scan. At the first diagnostic evaluation, 16 patients were given a clinical Alheimer’s disease diagnosis (14 PiB positive. Of the 57 patients, 13 (23% were diagnostically reclassified after PiB-PET ratings were disclosed. The clinicians’ overall confidence in their diagnosis increased in 28 (49% patients. Conclusion: PiB-PET adds to the specialist clinical evaluation and other supplemental diagnostic investigations in the diagnostic classification of patients with uncertain diagnosis in a specialized memory clinic.

Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification.

Science.gov (United States)

Hansen, Adam E; Andersen, Flemming L; Henriksen, Sarah T; Vignaud, Alexandre; Ardenkjaer-Larsen, Jan H; Højgaard, Liselotte; Kjaer, Andreas; Klausen, Thomas L

2016-12-01

Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and

PET Performance Evaluation of an MR-Compatible PET Insert

Science.gov (United States)

Wu, Yibao; Catana, Ciprian; Farrell, Richard; Dokhale, Purushottam A.; Shah, Kanai S.; Qi, Jinyi; Cherry, Simon R.

2010-01-01

A magnetic resonance (MR) compatible positron emission tomography (PET) insert has been developed in our laboratory for simultaneous small animal PET/MR imaging. This system is based on lutetium oxyorthosilicate (LSO) scintillator arrays with position-sensitive avalanche photodiode (PSAPD) photodetectors. The PET performance of this insert has been measured. The average reconstructed image spatial resolution was 1.51 mm. The sensitivity at the center of the field of view (CFOV) was 0.35%, which is comparable to the simulation predictions of 0.40%. The average photopeak energy resolution was 25%. The scatter fraction inside the MRI scanner with a line source was 12% (with a mouse-sized phantom and standard 35 mm Bruker 1H RF coil), 7% (with RF coil only) and 5% (without phantom or RF coil) for an energy window of 350–650 keV. The front-end electronics had a dead time of 390 ns, and a trigger extension dead time of 7.32 μs that degraded counting rate performance for injected doses above ~0.75 mCi (28 MBq). The peak noise-equivalent count rate (NECR) of 1.27 kcps was achieved at 290 μCi (10.7 MBq). The system showed good imaging performance inside a 7-T animal MRI system; however improvements in data acquisition electronics and reduction of the coincidence timing window are needed to realize improved NECR performance. PMID:21072320

Effects of ferumoxytol on quantitative PET measurements in simultaneous PET/MR whole-body imaging: a pilot study in a baboon model.

Science.gov (United States)

Borra, Ronald Jh; Cho, Hoon-Sung; Bowen, Spencer L; Attenberger, Ulrike; Arabasz, Grae; Catana, Ciprian; Josephson, Lee; Rosen, Bruce R; Guimaraes, Alexander R; Hooker, Jacob M

2015-12-01

Simultaneous PET/MR imaging depends on MR-derived attenuation maps (mu-maps) for accurate attenuation correction of PET data. Currently, these maps are derived from gradient-echo-based MR sequences, which are sensitive to susceptibility changes. Iron oxide magnetic nanoparticles have been used in the measurement of blood volume, tumor microvasculature, tumor-associated macrophages, and characterizing lymph nodes. Our aim in this study was to assess whether the susceptibility effects associated with iron oxide nanoparticles can potentially affect measured (18)F-FDG PET standardized uptake values (SUV) through effects on MR-derived attenuation maps. The study protocol was approved by the Institutional Animal Care and Use Committee. Using a Siemens Biograph mMR PET/MR scanner, we evaluated the effects of increasing concentrations of ferumoxytol and ferumoxytol aggregates on MR-derived mu-maps using an agarose phantom. In addition, we performed a baboon experiment evaluating the effects of a single i.v. ferumoxytol dose (10 mg/kg) on the liver, spleen, and pancreas (18)F-FDG SUV at baseline (ferumoxytol-naïve), within the first hour and at 1, 3, 5, and 11 weeks. Phantom experiments showed mu-map artifacts starting at ferumoxytol aggregate concentrations of 10 to 20 mg/kg. The in vivo baboon data demonstrated a 53% decrease of observed (18)F-FDG SUV compared to baseline within the first hour in the liver, persisting at least 11 weeks. A single ferumoxytol dose can affect measured SUV for at least 3 months, which should be taken into account when administrating ferumoxytol in patients needing sequential PET/MR scans. Advances in knowledge 1. Ferumoxytol aggregates, but not ferumoxytol alone, produce significant artifacts in MR-derived attenuation correction maps at approximate clinical dose levels of 10 mg/kg. 2. When performing simultaneous whole-body (18)F-FDG PET/MR, a single dose of ferumoxytol can result in observed SUV decreases up to 53%, depending on the

Comparison of PET/CT and PET/MRI hybrid systems using a 68Ga-labelled PSMA ligand for the diagnosis of recurrent prostate cancer: initial experience

International Nuclear Information System (INIS)

Afshar-Oromieh, A.; Haberkorn, U.; Schlemmer, H.P.; Fenchel, M.; Roethke, M.; Eder, M.; Eisenhut, M.; Hadaschik, B.A.; Kopp-Schneider, A.

2014-01-01

68 Ga-labelled HBED-CC-PSMA is a highly promising tracer for imaging recurrent prostate cancer (PCa). The intention of this study was to evaluate the feasibility of PET/MRI with this tracer. Twenty patients underwent PET/CT 1 h after injection of the 68 Ga-PSMA ligand followed by PET/MRI 3 h after injection. Data from the two investigations were first analysed separately and then compared with respect to tumour detection rate and radiotracer uptake in various tissues. To evaluate the quantification accuracy of the PET/MRI system, differences in SUVs between PET/CT and corresponding PET/MRI were compared with differences in SUVs between PET/CT 1 h and 3 h after injection in another patient cohort. This cohort was investigated using the same PET/CT system. With PET/MRI, different diagnostic sequences, higher contrast of lesions and higher resolution of MRI enabled a subjectively easier evaluation of the images. In addition, four unclear findings on PET/CT could be clarified as characteristic of PCa metastases by PET/MRI. However, in PET images of the PET/MRI, a reduced signal was observed at the level of the kidneys (in 11 patients) and around the urinary bladder (in 15 patients). This led to reduced SUVs in six lesions. SUV mean values provided by the PET/MRI system were different in muscles, blood pool, liver and spleen. PCa was detected more easily and more accurately with Ga-PSMA PET/MRI than with PET/CT and with lower radiation exposure. Consequently, this new technique could clarify unclear findings on PET/CT. However, scatter correction was challenging when the specific 68 Ga-PSMA ligand was used. Moreover, direct comparison of SUVs from PET/CT and PET/MR needs to be conducted carefully. (orig.)

Pet Problems at Home: Pet Problems in the Community.

Science.gov (United States)

Soltow, Willow

1984-01-01

Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…

Scintillator studies for the HPD-PET concept

CERN Document Server

Braem, D; Ciocia, F; De Leo, R; Joram, C; Lagamba, L; Nappi, E; Séguinot, Jacques; Vilardi, I; Weilhammer, P

2007-01-01

The spatial, energy, and time resolutions of 10 cm long polished YAP:Ce and LYSO:Ce crystals have been measured. The work is part of the novel HPD-PET concept, based on a full three-dimensional, free of parallax errors, reconstruction of the γ-ray interaction point in 10–15 cm long scintillators. The effective light attenuation length, a key parameter of the HPD-PET concept, and the resolutions have been measured for various wrappings and coatings of the crystal lateral surfaces. Even if the final HPD-PET prototype could use scintillators and/or wrappings different from those tested, the results here presented prove the feasibility of the concept and provide hints on its potential capabilities.

Conductive materials for proton exchange membrane fuel cell bipolar plates made from PVDF, PET and co-continuous PVDF/PET filled with carbon additives

Energy Technology Data Exchange (ETDEWEB)

Nguyen, L.; Mighri, F.; Deyrail, Y. [CREPEC, Center for Applied Research on Polymers and Composites, QC (Canada); Department of Chemical Engineering, Laval University, QC (Canada); Elkoun, S. [CREPEC, Center for Applied Research on Polymers and Composites, QC (Canada); Department of Mechanical Engineering, Sherbrooke University, QC (Canada)

2010-12-15

The aim of this work was to develop and characterise electrically conductive materials for proton exchange membrane fuel cells and bipolar plates (BPPs). These BPPs were made from highly conductive blends of polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF), as matrix phase. The conductive materials were developed from carefully formulated blends composed of conductive carbon black (CB) powder and, in some cases, graphite synthetic flakes mixed with pure PET, PVDF or with PVDF/PET systems. They were first developed by twin-screw extrusion process then compression-molded to give BPP final shape. As the developed blends have to meet properties suitable for BPP applications, they were characterised for their rheological properties, electrical through-plane resistivity (the inverse of conductivity), oxygen permeability, flexural and impact properties. Results showed that lower resistivity was obtained with PVDF/CB blends due to the higher interfacial energy between the PVDF matrix and CB and also the higher density and crystallinity of PVDF, compared to those of PET. It was also observed that the lowest resistivity values were obtained with mixing PVDF and PET at controlled compositions to ensure PVDF/PET co-continuous morphology. Also, slow cooling rates helped to attain the lowest values of through-plane resistivity for all studied blends. This behaviour was related to the higher crystallinity obtained with low cooling rates leading to smaller amorphous regions in which carbon particles are much more concentrated. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Patient-dependent count-rate adaptive normalization for PET detector efficiency with delayed-window coincidence events

International Nuclear Information System (INIS)

Niu, Xiaofeng; Ye, Hongwei; Xia, Ting; Asma, Evren; Gagnon, Daniel; Wang, Wenli; Winkler, Mark

2015-01-01

Quantitative PET imaging is widely used in clinical diagnosis in oncology and neuroimaging. Accurate normalization correction for the efficiency of each line-of- response is essential for accurate quantitative PET image reconstruction. In this paper, we propose a normalization calibration method by using the delayed-window coincidence events from the scanning phantom or patient. The proposed method could dramatically reduce the ‘ring’ artifacts caused by mismatched system count-rates between the calibration and phantom/patient datasets. Moreover, a modified algorithm for mean detector efficiency estimation is proposed, which could generate crystal efficiency maps with more uniform variance. Both phantom and real patient datasets are used for evaluation. The results show that the proposed method could lead to better uniformity in reconstructed images by removing ring artifacts, and more uniform axial variance profiles, especially around the axial edge slices of the scanner. The proposed method also has the potential benefit to simplify the normalization calibration procedure, since the calibration can be performed using the on-the-fly acquired delayed-window dataset. (paper)

PET/CT imaging in head and neck tumors

International Nuclear Information System (INIS)

Roedel, R.; Palmedo, H.; Reichmann, K.; Reinhardt, M.J.; Biersack, H.J.; Straehler-Pohl, H.J.; Jaeger, U.

2004-01-01

To evaluate the usefulness of combined PET/CT examinations for detection of malignant tumors and their metastases in head and neck oncology. 51 patients received whole body scans on a dual modality PET/CT system. CT was performed without i.v. contrast. The results were compared concerning the diagnostic impact of native CT scan on FDG-PET images and the additional value of fused imaging. From 153 lesions were 97 classified as malignant on CT and 136 on FDG/PET images, as suspicious for malignancy in 33 on CT and 7 on FDG-PET and as benign in 23 on CT and 10 on FDG-PET. With combined PET/CT all primary and recurrent tumors could be found, the detection rate in patients with unknown primary tumors was 45%. Compared to PET or CT alone the sensitivity, specifity and accuracy could be significantly improved by means of combined PET/CT. Fused PET/CT imaging with [F18]-FDG and native CT-scanning enables accurate diagnosis in 93% of lesions and 90% of patients with head and neck oncology. (orig.) [de

Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

International Nuclear Information System (INIS)

Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long; Peng, Weiai; Wang, Baijun

2014-01-01

To evaluate the concordance among 18 F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment 18 F-FDG PET/MR imaging. 18 F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV max ) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV max (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm 3 ) were similar (P > 0.05) at 35 % and 40 % of SUV max (32.91 ± 18.90 cm 3 and 27.56 ± 17.19 cm 3 respectively) and significantly correlated (P 3 . DW volumes were not significantly different from FDG PET volumes at either 35 % SUV max or 40 % SUV max or from T2-W imaging volumes (P > 0.05). PET subvolumes with increasing SUV max cut-off percentage showed an inverse change in mean ADC values on DW imaging (P max is recommended for 18 F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density. (orig.)

Pilot Study for the Prediction of Response to Radiotherapy Using [18F]Fluorothymidine PET in Nasopharyngeal Cancer: Comparison with [18F]FDG PET

International Nuclear Information System (INIS)

Baek, So Ra; Chae, Sun Young; Kim, Hye Ok; Lee, Sang Wook; Oh, Seung Jun; Im, Ki Chun; Moon, Dae Hyuk; Kim, Jae Seung; Ryu, Jin Sook

2009-01-01

This study was performed to know whether [ 18 F]Fluorothymidine (FLT) positron emission tomography (PET) can be used to monitor early response to radiotherapy in comparison with [ 18 F]Fluorodeoxyglucose (FDG) PET, and to establish the optimal imaging time for prediction of therapy response. Two patients with nasopharyngeal cancer underwent serial FLT PET and FDG PET before and during radiotherapy. Three on-treatment FLT and FDG PET scans were performed on 1 week, 2 weeks and 3 weeks (at each time of 10 Gy, 20 Gy and 30 Gy delivered). The peak standardized uptake values (SUV peak ) of primary tumors were measured on FLT and FDG PET. Then, percent changes of SUV peak after therapy were calculated. In two patients, baseline values of SUV peak on FDT PET were higher than those on FLT PET (FLT vs FDG; 3.7 vs 5.0, and 5.7 vs 15.0). In patient 1, FLT SUV peak showed 78%, 78% and 84% of decrease on 1 week, 2 and 3 weeks after treatment, whereas FDG SUV peak showed 18%, 52% and 66% of decrease, respectively. In patient 2, FLT SUV peak showed 75%, 75% and 68% of decrease, whereas FDG SUV peak showed 51%, 49% and 58% of decrease, respectively. Both patients reached to complete remission after radiotherapy. After radiotherapy, the decrease of FLT tumor uptake preceded the decrease of FDG tumor uptake in patients with nasopharyngeal cancer, and 1 week after therapy may be appropriate time for the assessment of early response. FLT PET might be more useful than FDG PET for monitoring early response to radiotherapy

Influence of the clay in the stress cracking resistance of PET; Influencia de silicatos em camadas na resistencia ao 'stress cracking' do PET

Energy Technology Data Exchange (ETDEWEB)

Teofilo, Edvania T. [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, Universidade Federal de Campina Grande, PB (Brazil); Silva, Emanuela S.; Silva, Suedina M.L.; Rabello, Marcelo S., E-mail: marcelo@dema.ufcg.edu.b [Unidade Academica de Engenharia de Materiais, Universidade Federal de Campina Grande, PB (Brazil)

2011-07-01

The environmental stress cracking resistance in PET and hybrid PET/clay were conducted under stress relaxation test. X-ray diffraction analysis show that was obtained immiscible system. In the absence of aggressive fluids the hybrid exhibited higher relaxation rates than the PET. Already in contact with aggressive fluids showed a similar or lower relaxation rate than the PET, being more resistant. Suggesting that the clay, though not interlayer, interferes with the distribution of the stress cracking agent. Thus, the barrier effect caused by the clay was more significant than the stress concentration caused by it. (author)

Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

Energy Technology Data Exchange (ETDEWEB)

Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long [Shengjing Hospital of China Medical University, Department of Radiology, Shenyang, Liaoning (China); Peng, Weiai [NM Marketing, Great China, Philips Healthcare, Guangzhou (China); Wang, Baijun [Philips China Investment Co. Ltd. Shenyang Office, Shenyang, Liaoning (China)

2014-05-15

To evaluate the concordance among {sup 18}F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment {sup 18}F-FDG PET/MR imaging. {sup 18}F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV{sub max}) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV{sub max} (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm{sup 3}) were similar (P > 0.05) at 35 % and 40 % of SUV{sub max} (32.91 ± 18.90 cm{sup 3} and 27.56 ± 17.19 cm{sup 3} respectively) and significantly correlated (P < 0.001; r = 0.735 and 0.766). The mean DW volume was 30.48 ± 22.41 cm{sup 3}. DW volumes were not significantly different from FDG PET volumes at either 35 % SUV{sub max} or 40 % SUV{sub max} or from T2-W imaging volumes (P > 0.05). PET subvolumes with increasing SUV{sub max} cut-off percentage showed an inverse change in mean ADC values on DW imaging (P < 0.001, ANOVA). Hybrid PET/MR showed strong volume concordance between FDG PET, and T2-W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV{sub max} is recommended for {sup 18}F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density. (orig.)

In situ prepared PET nanocomposites: Effect of organically modified montmorillonite and fumed silica nanoparticles on PET physical properties and thermal degradation kinetics

International Nuclear Information System (INIS)

Vassiliou, A.A.; Chrissafis, K.; Bikiaris, D.N.

2010-01-01

In the present study a series of PET nanocomposites were prepared by in situ polymerization using different amounts of organically modified montmorillonite (OMMT) with a triphenylphosphine compound and fumed silica nanoparticles (SiO 2 ). As verified by TEM micrographs, the dispersion of both nanoparticles into the PET matrix was homogeneous while montmorillonite was dispersed in the exfoliated form. The intrinsic viscosities of the prepared nanocomposites were affected by the addition of the nanoparticles and in both cases a slight increase was observed. Tensile strength was also increased by increasing nanoparticles content while both types of nanoparticles act as nucleating agents, enhancing the crystallization rates of PET. From the thermogravimetric curves it was concluded that PET and the samples with different nanoparticles presented good thermostability, since no remarkable mass loss occurred up to 320 o C ( 2 2 wt.% nanocomposites was almost identical (222.1 kJ/mol). However, PET/OMMT 2 wt.% nanocomposites exhibited a higher activation energy (228.3 kJ/mol), indicating that OMMT incurred a stabilizing effect upon the decomposition of the matrix. The form of the conversion function for all the studied samples obtained by fitting was the mechanism of n th -order auto-catalysis.

National Electrical Manufacturers Association NU-4 performance evaluation of the PET component of the NanoPET/CT preclinical PET/CT scanner.

Science.gov (United States)

Szanda, Istvan; Mackewn, Jane; Patay, Gergely; Major, Peter; Sunassee, Kavitha; Mullen, Gregory E; Nemeth, Gabor; Haemisch, York; Blower, Philip J; Marsden, Paul K

2011-11-01

The NanoPET/CT represents the latest generation of commercial preclinical PET/CT systems. This article presents a performance evaluation of the PET component of the system according to the National Electrical Manufacturers Association (NEMA) NU-4 2008 standard. The NanoPET/CT consists of 12 lutetium yttrium orthosilicate:cerium modular detectors forming 1 ring, with 9.5-cm axial coverage and a 16-cm animal port. Each detector crystal is 1.12 × 1.12 × 13 mm, and 1 module contains 81 × 39 of these crystals. An optical light guide transmits the scintillation light to the flat-panel multianode position-sensitive photomultiplier tubes. Analog-to-digital converter cards and a field-programmable gate array-based data-collecting card provide the readout. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with the NEMA NU-4 standard. Energy and temporal resolution measurements and a mouse imaging study were performed in addition to the standard. Energy resolution was 19% at 511 keV. The spatial resolution, measured as full width at half maximum on single-slice rebinning/filtered backprojection-reconstructed images, approached 1 mm on the axis and remained below 2.5 mm in the central 5-cm transaxial region both in the axial center and at one-quarter field of view. The maximum absolute sensitivity for a point source at the center of the field of view was 7.7%. The maximum noise equivalent counting rates were 430 kcps at 36 MBq and 130 kcps at 27 MBq for the mouse- and rat-sized phantoms, respectively. The uniformity and recovery coefficients were measured with the image-quality phantom, giving good-quality images. In a mouse study with an (18)F-labeled thyroid-specific tracer, the 2 lobes of the thyroid were clearly distinguishable, despite the small size of this organ. The flexible readout system allowed experiments to be performed in an efficient manner, and the system remained stable throughout. The large number

Imaging with 124I in differentiated thyroid carcinoma: is PET/MRI superior to PET/CT?

International Nuclear Information System (INIS)

Binse, I.; Poeppel, T.D.; Ruhlmann, M.; Gomez, B.; Bockisch, A.; Rosenbaum-Krumme, S.J.; Umutlu, L.

2016-01-01

The aim of this study was to compare integrated PET/CT and PET/MRI for their usefulness in detecting and categorizing cervical iodine-positive lesions in patients with differentiated thyroid cancer using 124 I as tracer. The study group comprised 65 patients at high risk of iodine-positive metastasis who underwent PET/CT (low-dose CT scan, PET acquisition time 2 min; PET/CT 2 ) followed by PET/MRI of the neck 24 h after 124 I administration. PET images from both modalities were analysed for the numbers of tracer-positive lesions. Two different acquisition times were used for the comparisons, one matching the PET/CT 2 acquisition time (2 min, PET/MRI 2 ) and the other covering the whole MRI scan time (30 min, PET/MRI 30 ). Iodine-positive lesions were categorized as metastasis, thyroid remnant or inconclusive according to their location on the PET/CT images. Morphological information provided by MRI was considered for evaluation of lesions on PET/MRI and for volume information. PET/MRI 2 detected significantly more iodine-positive metastases and thyroid remnants than PET/CT 2 (72 vs. 60, p = 0.002, and 100 vs. 80, p = 0.001, respectively), but the numbers of patients with at least one tumour lesion identified were not significantly different (21/65 vs. 17/65 patients). PET/MRI 30 tended to detect more PET-positive metastases than PET/MRI 2 (88 vs. 72), but the difference was not significant (p = 0.07). Of 21 lesions classified as inconclusive on PET/CT, 5 were assigned to metastasis or thyroid remnant when evaluated by PET/MRI. Volume information was available in 34 % of iodine-positive metastases and 2 % of thyroid remnants on PET/MRI. PET/MRI of the neck was found to be superior to PET/CT in detecting iodine-positive lesions. This was attributed to the higher sensitivity of the PET component, Although helpful in some cases, we found no substantial advantage of PET/MRI over PET/CT in categorizing iodine-positive lesions as either metastasis or thyroid remnant

PET-Studies in parkinson's disease; Untersuchungen mit der Positronen-Emissions-Tomographie (PET) bei Patienten mit Morbus Parkinson

Energy Technology Data Exchange (ETDEWEB)

Schwarz, J. [Klinik fuer Neurologie, Univ. Leipzig (Germany)

2002-09-01

Positron-emission-tomography (PET) has enabled to study the metabolism and blood flow in specific brain areas. Besides, there is a variety of radiotracers that allow quantification of the function of distinct molecules. In respect to Parkinson's disease, PET allowed for the first time to assess the number of dopaminergic neurons in vivo. Thus, helping confirming a dopaminergic deficit, measuring disease progression and also help to determine the function of dopaminergic grafts. Current research has shifted to determine the role of related neurotransmitter systems in the pathophysiology of Parkinson's disease. (orig.) [German] Die positronen-emissions-tomographie (PET) bietet neben der Messung von Metabolismus und Blutfluss die Moeglichkeit der Darstellung von einzelnen Molekuelen. Bei Patienten mit Morbus Parkinson hat es diese Technik erstmals erlaubt, die Anzahl der dopaminergen Neurone zu quantifizieren, wodurch die Diagnose gesichert, die Progression der Erkrankung beurteilt und auch das Anwachsen von Implantaten beurteilt werden kann. Die PET hat einen wesentlichen Beitrag zu unserem heutigen Wissen ueber die Pathophysiologie dieser Erkrankung beigetragen. (orig.)

The spatial distribution of pet dogs and pet cats on the island of Ireland

Directory of Open Access Journals (Sweden)

More Simon J

2011-06-01

Full Text Available Abstract Background There is considerable international research regarding the link between human demographics and pet ownership. In several international studies, pet ownership was associated with household demographics including: the presence of children in the household, urban/rural location, level of education and age/family structure. What is lacking across all these studies, however, is an understanding of how these pets are spatially distributed throughout the regions under study. This paper describes the spatial distribution of pet dog and pet cat owning households on the island of Ireland. Results In 2006, there were an estimated 640,620 pet dog owning households and 215,542 pet cat owning households in Ireland. These estimates are derived from logistic regression modelling, based on household composition to determine pet dog ownership and the type of house to determine pet cat ownership. Results are presented using chloropleth maps. There is a higher density of pet dog owning households in the east of Ireland and in the cities than the west of Ireland and rural areas. However, in urban districts there are a lower proportion of households owning pet dogs than in rural districts. There are more households with cats in the urban areas, but the proportion of households with cats is greater in rural areas. Conclusions The difference in spatial distribution of dog ownership is a reflection of a generally higher density of households in the east of Ireland and in major cities. The higher proportion of ownership in the west is understandable given the higher proportion of farmers and rural dwellings in this area. Spatial representation allows us to visualise the impact of human household distribution on the density of both pet dogs and pet cats on the island of Ireland. This information can be used when analysing risk of disease spread, for market research and for instigating veterinary care.

Quantification of myocardial blood flow with 11C-hydroxyephedrine dynamic PET: comparison with 15O-H2O PET.

Science.gov (United States)

Hiroshima, Yuji; Manabe, Osamu; Naya, Masanao; Tomiyama, Yuuki; Magota, Keiichi; Obara, Masahiko; Aikawa, Tadao; Oyama-Manabe, Noriko; Yoshinaga, Keiichiro; Hirata, Kenji; Kroenke, Markus; Tamaki, Nagara; Katoh, Chietsugu

2017-12-21

11 C-hydroxyephedrine (HED) PET has been used to evaluate the myocardial sympathetic nervous system (SNS). Here we sought to establish a simultaneous approach for quantifying both myocardial blood flow (MBF) and the SNS from a single HED PET scan. Ten controls and 13 patients with suspected cardiac disease were enrolled. The inflow rate of 11 C-HED (K1) was obtained using a one-tissue-compartment model. We compared this rate with the MBF derived from 15 O-H 2 O PET. In the controls, the relationship between K 1 from 11 C-HED PET and the MBF from 15 O-H 2 O PET was linked by the Renkin-Crone model. The relationship between K 1 from 11 C-HED PET and the MBF from 15 O-H 2 O PET from the controls' data was approximated as follows: K 1   =  (1 - 0.891 * exp(- 0.146/MBF)) * MBF. In the validation set, the correlation coefficient demonstrated a significantly high relationship for both the whole left ventricle (r = 0.95, P < 0.001) and three coronary territories (left anterior descending artery: r = 0.96, left circumflex artery: r = 0.81, right coronary artery: r =  0.86; P < 0.001, respectively). 11 C-HED can simultaneously estimate MBF and sympathetic nervous function without requiring an additional MBF scan for assessing mismatch areas between MBF and SNS.

Imaging performance of LabPET APD-based digital PET scanners for pre-clinical research

International Nuclear Information System (INIS)

Bergeron, Mélanie; Cadorette, Jules; Beaudoin, Jean-François; Lecomte, Roger; Tétrault, Marc-André; Leroux, Jean-Daniel; Fontaine, Réjean

2014-01-01

The LabPET is an avalanche photodiode (APD) based digital PET scanner with quasi-individual detector read-out and highly parallel electronic architecture for high-performance in vivo molecular imaging of small animals. The scanner is based on LYSO and LGSO scintillation crystals (2×2×12/14 mm 3 ), assembled side-by-side in phoswich pairs read out by an APD. High spatial resolution is achieved through the individual and independent read-out of an individual APD detector for recording impinging annihilation photons. The LabPET exists in three versions, LabPET4 (3.75 cm axial length), LabPET8 (7.5 cm axial length) and LabPET12 (11.4 cm axial length). This paper focuses on the systematic characterization of the three LabPET versions using two different energy window settings to implement a high-efficiency mode (250–650 keV) and a high-resolution mode (350–650 keV) in the most suitable operating conditions. Prior to measurements, a global timing alignment of the scanners and optimization of the APD operating bias have been carried out. Characteristics such as spatial resolution, absolute sensitivity, count rate performance and image quality have been thoroughly investigated following the NEMA NU 4-2008 protocol. Phantom and small animal images were acquired to assess the scanners' suitability for the most demanding imaging tasks in preclinical biomedical research. The three systems achieve the same radial FBP spatial resolution at 5 mm from the field-of-view center: 1.65/3.40 mm (FWHM/FWTM) for an energy threshold of 250 keV and 1.51/2.97 mm for an energy threshold of 350 keV. The absolute sensitivity for an energy window of 250–650 keV is 1.4%/2.6%/4.3% for LabPET4/8/12, respectively. The best count rate performance peaking at 362 kcps is achieved by the LabPET12 with an energy window of 250–650 keV and a mouse phantom (2.5 cm diameter) at an activity of 2.4 MBq ml −1 . With the same phantom, the scatter fraction for all scanners is about

Regression analysis utilizing subjective evaluation of emotional experience in PET studies on emotions.

Science.gov (United States)

Aalto, Sargo; Wallius, Esa; Näätänen, Petri; Hiltunen, Jaana; Metsähonkala, Liisa; Sipilä, Hannu; Karlsson, Hasse

2005-09-01

A methodological study on subject-specific regression analysis (SSRA) exploring the correlation between the neural response and the subjective evaluation of emotional experience in eleven healthy females is presented. The target emotions, i.e., amusement and sadness, were induced using validated film clips, regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET), and the subjective intensity of the emotional experience during the PET scanning was measured using a category ratio (CR-10) scale. Reliability analysis of the rating data indicated that the subjects rated the intensity of their emotional experience fairly consistently on the CR-10 scale (Cronbach alphas 0.70-0.97). A two-phase random-effects analysis was performed to ensure the generalizability and inter-study comparability of the SSRA results. Random-effects SSRAs using Statistical non-Parametric Mapping 99 (SnPM99) showed that rCBF correlated with the self-rated intensity of the emotional experience mainly in the brain regions that were identified in the random-effects subtraction analyses using the same imaging data. Our results give preliminary evidence of a linear association between the neural responses related to amusement and sadness and the self-evaluated intensity of the emotional experience in several regions involved in the emotional response. SSRA utilizing subjective evaluation of emotional experience turned out a feasible and promising method of analysis. It allows versatile exploration of the neurobiology of emotions and the neural correlates of actual and individual emotional experience. Thus, SSRA might be able to catch the idiosyncratic aspects of the emotional response better than traditional subtraction analysis.

SU-F-I-57: Evaluate and Optimize PET Acquisition Overlap in 18F-FDG Oncology Wholebody PET/CT: Can We Scan PET Faster?

International Nuclear Information System (INIS)

Zhang, J; Natwa, M; Hall, NC; Knopp, MV; Knopp, MU; Zhang, B; Tung, C

2016-01-01

Purpose: The longer patient has to remain on the table during PET imaging, the higher the likelihood of motion artifacts due to patient discomfort. This study was to investigate and optimize PET acquisition overlap in 18F-FDG oncology wholebody PET/CT to speed up PET acquisition and improve patient comfort. Methods: Wholebody 18F-FDG PET/CT of phantoms, 8 pre-clinical patients (beagles) and 5 clinical oncology patients were performed in 90s/bed on a time-of-flight Gemini TF 64 system. Imaging of phantoms and beagles was acquired with reduced PET overlaps (40%, 33%, 27%, 20%, 13% and no overlap) in addition to the system default (53%). In human studies, 1 or 2 reduced overlaps from the listed options were used to acquire PET/CT sweeps right after the default standard of care imaging. Image quality was blindly reviewed using visual scoring criteria and quantitative SUV assessment. NEMA PET sensitivity was performed under different overlaps. Results: All PET exams demonstrated no significant impact on the visual grades for overlaps >20%. Blinded reviews assigned the best visual scores to PET using overlaps 53%–27%. Reducing overlap to 27% for oncology patients (12-bed) saved an average of ∼40% acquisition time (11min) compared to using the default overlap (18min). No significant SUV variances were found when reducing overlap to half of default for cerebellum, lung, heart, aorta, liver, fat, muscle, bone marrow, thighs and target lesions (p>0.05), except expected variability in urinary system. Conclusion: This study demonstrated by combined phantom, pre-clinical and clinical PET/CT scans that PET acquisition overlap in axial of today’s systems can be reduced and optimized. It showed that a reduction of PET acquisition overlap to 27% (half of system default) can be implemented to reduce table time by ∼40% to improve patient comfort and minimize potential motion artifacts, without prominently degrading image quality or compromising PET quantification.

SU-F-I-57: Evaluate and Optimize PET Acquisition Overlap in 18F-FDG Oncology Wholebody PET/CT: Can We Scan PET Faster?

Energy Technology Data Exchange (ETDEWEB)

Zhang, J; Natwa, M; Hall, NC; Knopp, MV [The Ohio State University, Columbus, OH (United States); Knopp, MU [Pepperdine University, Malibu, CA (United States); Zhang, B; Tung, C [Philips Healthcare, Highland Heights, OH (United States)

2016-06-15

Purpose: The longer patient has to remain on the table during PET imaging, the higher the likelihood of motion artifacts due to patient discomfort. This study was to investigate and optimize PET acquisition overlap in 18F-FDG oncology wholebody PET/CT to speed up PET acquisition and improve patient comfort. Methods: Wholebody 18F-FDG PET/CT of phantoms, 8 pre-clinical patients (beagles) and 5 clinical oncology patients were performed in 90s/bed on a time-of-flight Gemini TF 64 system. Imaging of phantoms and beagles was acquired with reduced PET overlaps (40%, 33%, 27%, 20%, 13% and no overlap) in addition to the system default (53%). In human studies, 1 or 2 reduced overlaps from the listed options were used to acquire PET/CT sweeps right after the default standard of care imaging. Image quality was blindly reviewed using visual scoring criteria and quantitative SUV assessment. NEMA PET sensitivity was performed under different overlaps. Results: All PET exams demonstrated no significant impact on the visual grades for overlaps >20%. Blinded reviews assigned the best visual scores to PET using overlaps 53%–27%. Reducing overlap to 27% for oncology patients (12-bed) saved an average of ∼40% acquisition time (11min) compared to using the default overlap (18min). No significant SUV variances were found when reducing overlap to half of default for cerebellum, lung, heart, aorta, liver, fat, muscle, bone marrow, thighs and target lesions (p>0.05), except expected variability in urinary system. Conclusion: This study demonstrated by combined phantom, pre-clinical and clinical PET/CT scans that PET acquisition overlap in axial of today’s systems can be reduced and optimized. It showed that a reduction of PET acquisition overlap to 27% (half of system default) can be implemented to reduce table time by ∼40% to improve patient comfort and minimize potential motion artifacts, without prominently degrading image quality or compromising PET quantification.

Comparison of PET/CT and PET/MRI hybrid systems using a {sup 68}Ga-labelled PSMA ligand for the diagnosis of recurrent prostate cancer: initial experience

Energy Technology Data Exchange (ETDEWEB)

Afshar-Oromieh, A. [University Hospital Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Haberkorn, U. [University Hospital Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); German Cancer Research Center (DKFZ), Clinical Cooperation Unit of Nuclear Medicine, Heidelberg (Germany); Schlemmer, H.P.; Fenchel, M.; Roethke, M. [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Eder, M.; Eisenhut, M. [German Cancer Research Center (DKFZ), Department of Radiopharmaceutical Chemistry, Heidelberg (Germany); Hadaschik, B.A. [University Hospital Heidelberg, Department of Urology, Heidelberg (Germany); Kopp-Schneider, A. [German Cancer Research Center (DKFZ), Department of Biostatistics, Heidelberg (Germany)

2014-05-15

{sup 68}Ga-labelled HBED-CC-PSMA is a highly promising tracer for imaging recurrent prostate cancer (PCa). The intention of this study was to evaluate the feasibility of PET/MRI with this tracer. Twenty patients underwent PET/CT 1 h after injection of the {sup 68}Ga-PSMA ligand followed by PET/MRI 3 h after injection. Data from the two investigations were first analysed separately and then compared with respect to tumour detection rate and radiotracer uptake in various tissues. To evaluate the quantification accuracy of the PET/MRI system, differences in SUVs between PET/CT and corresponding PET/MRI were compared with differences in SUVs between PET/CT 1 h and 3 h after injection in another patient cohort. This cohort was investigated using the same PET/CT system. With PET/MRI, different diagnostic sequences, higher contrast of lesions and higher resolution of MRI enabled a subjectively easier evaluation of the images. In addition, four unclear findings on PET/CT could be clarified as characteristic of PCa metastases by PET/MRI. However, in PET images of the PET/MRI, a reduced signal was observed at the level of the kidneys (in 11 patients) and around the urinary bladder (in 15 patients). This led to reduced SUVs in six lesions. SUV{sub mean} values provided by the PET/MRI system were different in muscles, blood pool, liver and spleen. PCa was detected more easily and more accurately with Ga-PSMA PET/MRI than with PET/CT and with lower radiation exposure. Consequently, this new technique could clarify unclear findings on PET/CT. However, scatter correction was challenging when the specific {sup 68}Ga-PSMA ligand was used. Moreover, direct comparison of SUVs from PET/CT and PET/MR needs to be conducted carefully. (orig.)

Direct parametric reconstruction in dynamic PET myocardial perfusion imaging: in vivo studies

Science.gov (United States)

Petibon, Yoann; Rakvongthai, Yothin; El Fakhri, Georges; Ouyang, Jinsong

2017-05-01

Dynamic PET myocardial perfusion imaging (MPI) used in conjunction with tracer kinetic modeling enables the quantification of absolute myocardial blood flow (MBF). However, MBF maps computed using the traditional indirect method (i.e. post-reconstruction voxel-wise fitting of kinetic model to PET time-activity-curves-TACs) suffer from poor signal-to-noise ratio (SNR). Direct reconstruction of kinetic parameters from raw PET projection data has been shown to offer parametric images with higher SNR compared to the indirect method. The aim of this study was to extend and evaluate the performance of a direct parametric reconstruction method using in vivo dynamic PET MPI data for the purpose of quantifying MBF. Dynamic PET MPI studies were performed on two healthy pigs using a Siemens Biograph mMR scanner. List-mode PET data for each animal were acquired following a bolus injection of ~7-8 mCi of 18F-flurpiridaz, a myocardial perfusion agent. Fully-3D dynamic PET sinograms were obtained by sorting the coincidence events into 16 temporal frames covering ~5 min after radiotracer administration. Additionally, eight independent noise realizations of both scans—each containing 1/8th of the total number of events—were generated from the original list-mode data. Dynamic sinograms were then used to compute parametric maps using the conventional indirect method and the proposed direct method. For both methods, a one-tissue compartment model accounting for spillover from the left and right ventricle blood-pools was used to describe the kinetics of 18F-flurpiridaz. An image-derived arterial input function obtained from a TAC taken in the left ventricle cavity was used for tracer kinetic analysis. For the indirect method, frame-by-frame images were estimated using two fully-3D reconstruction techniques: the standard ordered subset expectation maximization (OSEM) reconstruction algorithm on one side, and the one-step late maximum a posteriori (OSL-MAP) algorithm on the other

Direct parametric reconstruction in dynamic PET myocardial perfusion imaging: in-vivo studies

Science.gov (United States)

Petibon, Yoann; Rakvongthai, Yothin; Fakhri, Georges El; Ouyang, Jinsong

2017-01-01

Dynamic PET myocardial perfusion imaging (MPI) used in conjunction with tracer kinetic modeling enables the quantification of absolute myocardial blood flow (MBF). However, MBF maps computed using the traditional indirect method (i.e. post-reconstruction voxel-wise fitting of kinetic model to PET time-activity-curves -TACs) suffer from poor signal-to-noise ratio (SNR). Direct reconstruction of kinetic parameters from raw PET projection data has been shown to offer parametric images with higher SNR compared to the indirect method. The aim of this study was to extend and evaluate the performance of a direct parametric reconstruction method using in-vivo dynamic PET MPI data for the purpose of quantifying MBF. Dynamic PET MPI studies were performed on two healthy pigs using a Siemens Biograph mMR scanner. List-mode PET data for each animal were acquired following a bolus injection of ~7-8 mCi of 18F-flurpiridaz, a myocardial perfusion agent. Fully-3D dynamic PET sinograms were obtained by sorting the coincidence events into 16 temporal frames covering ~5 min after radiotracer administration. Additionally, eight independent noise realizations of both scans - each containing 1/8th of the total number of events - were generated from the original list-mode data. Dynamic sinograms were then used to compute parametric maps using the conventional indirect method and the proposed direct method. For both methods, a one-tissue compartment model accounting for spillover from the left and right ventricle blood-pools was used to describe the kinetics of 18F-flurpiridaz. An image-derived arterial input function obtained from a TAC taken in the left ventricle cavity was used for tracer kinetic analysis. For the indirect method, frame-by-frame images were estimated using two fully-3D reconstruction techniques: the standard Ordered Subset Expectation Maximization (OSEM) reconstruction algorithm on one side, and the One-Step Late Maximum a Posteriori (OSL-MAP) algorithm on the other

Comparison of standard and delayed imaging to improve the detection rate of [{sup 68}Ga]PSMA I and T PET/CT in patients with biochemical recurrence or prostate-specific antigen persistence after primary therapy for prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Schmuck, Sebastian; Nordlohne, Stefan; Sohns, Jan M.; Ross, Tobias L.; Bengel, Frank M.; Derlin, Thorsten [Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany); Klot, Christoph A. von [Hannover Medical School, Department of Urology and Urologic Oncology, Hannover (Germany); Henkenberens, Christoph; Christiansen, Hans [Hannover Medical School, Department of Radiation Oncology, Hannover (Germany); Wester, Hans-Juergen [Technische Universitaet Muenchen, Pharmaceutical Radiochemistry, Garching (Germany)

2017-06-15

The aim of this study was to assess the value of dual-time point imaging in PET/CT for detection of biochemically recurrent or persistent prostate cancer, using the prostate-specific membrane antigen (PSMA) ligand [{sup 68}Ga]PSMA I and T. 240 patients who underwent a [{sup 68}Ga]PSMA I and T PET/CT in the context of biochemical relapse of prostate cancer were included in this retrospective analysis. Imaging consisted of a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified proportions of positive PET/CT results, standardized uptake values and target-to-background ratios were analyzed, and compared between standard and delayed imaging. The overall detection rates of [{sup 68}Ga]PSMA I and T PET/CT were 94.2, 71.8, 58.6, 55.9 and 38.9% for PSA levels of ≥2, 1 to <2, 0.5 to <1, >0.2 to <0.5, and 0.01 to 0.2 ng/mL, respectively. Although the target-to-background ratio improved significantly over time (P < 0.0001), the majority (96.6%) of all lesions suggestive of recurrent disease could already be detected in standard imaging. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 5.4% (10/184) of abnormal [{sup 68}Ga]PSMA I and T PET/CT scans, and exclusively detected 3.4% (38/1134) of all lesions suggestive of recurrent disease. [{sup 68}Ga]PSMA I and T PET/CT shows high detection rates in patients with prostate-specific antigen persistence or biochemical recurrence of prostate cancer. Delayed imaging can detect lesions with improved contrast compared to standard imaging. However, the impact on detection rates was limited in this study. (orig.)

Comparison of standard and delayed imaging to improve the detection rate of ["6"8Ga]PSMA I and T PET/CT in patients with biochemical recurrence or prostate-specific antigen persistence after primary therapy for prostate cancer

International Nuclear Information System (INIS)

Schmuck, Sebastian; Nordlohne, Stefan; Sohns, Jan M.; Ross, Tobias L.; Bengel, Frank M.; Derlin, Thorsten; Klot, Christoph A. von; Henkenberens, Christoph; Christiansen, Hans; Wester, Hans-Juergen

2017-01-01

The aim of this study was to assess the value of dual-time point imaging in PET/CT for detection of biochemically recurrent or persistent prostate cancer, using the prostate-specific membrane antigen (PSMA) ligand ["6"8Ga]PSMA I and T. 240 patients who underwent a ["6"8Ga]PSMA I and T PET/CT in the context of biochemical relapse of prostate cancer were included in this retrospective analysis. Imaging consisted of a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified proportions of positive PET/CT results, standardized uptake values and target-to-background ratios were analyzed, and compared between standard and delayed imaging. The overall detection rates of ["6"8Ga]PSMA I and T PET/CT were 94.2, 71.8, 58.6, 55.9 and 38.9% for PSA levels of ≥2, 1 to 0.2 to <0.5, and 0.01 to 0.2 ng/mL, respectively. Although the target-to-background ratio improved significantly over time (P < 0.0001), the majority (96.6%) of all lesions suggestive of recurrent disease could already be detected in standard imaging. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 5.4% (10/184) of abnormal ["6"8Ga]PSMA I and T PET/CT scans, and exclusively detected 3.4% (38/1134) of all lesions suggestive of recurrent disease. ["6"8Ga]PSMA I and T PET/CT shows high detection rates in patients with prostate-specific antigen persistence or biochemical recurrence of prostate cancer. Delayed imaging can detect lesions with improved contrast compared to standard imaging. However, the impact on detection rates was limited in this study. (orig.)

Sensory analysis of pet foods.

Science.gov (United States)

Koppel, Kadri

2014-08-01

Pet food palatability depends first and foremost on the pet and is related to the pet food sensory properties such as aroma, texture and flavor. Sensory analysis of pet foods may be conducted by humans via descriptive or hedonic analysis, pets via acceptance or preference tests, and through a number of instrumental analysis methods. Sensory analysis of pet foods provides additional information on reasons behind palatable and unpalatable foods as pets lack linguistic capabilities. Furthermore, sensory analysis may be combined with other types of information such as personality and environment factors to increase understanding of acceptable pet foods. Most pet food flavor research is proprietary and, thus, there are a limited number of publications available. Funding opportunities for pet food studies would increase research and publications and this would help raise public awareness of pet food related issues. This mini-review addresses current pet food sensory analysis literature and discusses future challenges and possibilities. © 2014 Society of Chemical Industry.

[68Ga]DOTATATE PET/MRI and [18F]FDG PET/CT are complementary and superior to diffusion-weighted MR imaging for radioactive-iodine-refractory differentiated thyroid cancer

International Nuclear Information System (INIS)

Vrachimis, Alexis; Stegger, Lars; Wenning, Christian; Noto, Benjamin; Konnert, Julia Renate; Riemann, Burkhard; Weckesser, Matthias; Burg, Matthias Christian; Allkemper, Thomas; Heindel, Walter; Schaefers, Michael

2016-01-01

The purpose of this study was to determine whether [ 68 Ga]DOTATATE PET/MRI with diffusion-weighted imaging (DWI) can replace or complement [ 18 F]FDG PET/CT in patients with radioactive-iodine (RAI)-refractory differentiated thyroid cancer (DTC). The study population comprised 12 patients with elevated thyroglobulin and a negative RAI scan after thyroidectomy and RAI remnant ablation who underwent both [ 18 F]FDG PET/CT and [ 68 Ga]DOTATATE PET/MRI within 8 weeks of each other. The presence of recurrent cancer was evaluated on a per-patient, per-organ and per-lesion basis. Histology, and prior and follow-up examinations served as the standard of reference. Recurrent or metastatic tumour was confirmed in 11 of the 12 patients. [ 68 Ga]DOTATATE PET(/MRI) correctly identified the tumour burden in all 11 patients, whereas in one patient local relapse was missed by [ 18 F]FDG PET/CT. In the lesion-based analysis, overall lesion detection rates were 79/85 (93 %), 69/85 (81 %) and 27/82 (33 %) for [ 18 F]FDG PET/CT, [ 68 Ga]DOTATATE PET/MRI and DWI, respectively. [ 18 F]FDG PET(/CT) was superior to [ 68 Ga]DOTATATE PET(/MRI) in the overall evaluation and in the detection of pulmonary metastases. In the detection of extrapulmonary metastases, [ 68 Ga]DOTATATE PET(/MRI) showed a higher sensitivity than [ 18 F]FDG PET(/CT), at the cost of lower specificity. DWI achieved only poor sensitivity and was significantly inferior to [ 18 F]FDG PET in the lesion-based evaluation in the detection of both extrapulmonary and pulmonary metastases. [ 18 F]FDG PET/CT was more sensitive than [ 68 Ga]DOTATATE PET/MRI in the evaluation of RAI-refractory DTC, mostly because of its excellent ability to detect lung metastases. In the evaluation of extrapulmonary lesions, [ 68 Ga]DOTATATE PET(/MRI) was more sensitive and [ 18 F]FDG PET(/CT) more specific. Furthermore, DWI did not provide additional information and cannot replace [ 18 F]FDG PET for postoperative monitoring of patients with

Feasibility of simultaneous PET/MR of the carotid artery: first clinical experience and comparison to PET/CT

DEFF Research Database (Denmark)

Ripa, Rasmus Sejersten; Knudsen, Andreas; Hag, Anne Mette Fisker

2013-01-01

The study aimed at comparing PET/MR to PET/CT for imaging the carotid arteries in patients with known increased risk of atherosclerosis. Six HIV-positive men underwent sequential PET/MR and PET/CT of the carotid arteries after injection of 400 MBq of 18F-FDG. PET/MR was performed a median of 131......) indicating that the luminal 18F-FDG content had minimal influence on the values. The study shows for the first time that simultaneous PET/MR of the carotid arteries is feasible in patients with increased risk of atherosclerosis. Quantification of 18F-FDG uptake correlated well between PET/MR and PET...

Longitudinal studies of the 18F-FDG kinetics after ipilimumab treatment in metastatic melanoma patients based on dynamic FDG PET/CT.

Science.gov (United States)

Sachpekidis, Christos; Anwar, Hoda; Winkler, Julia K; Kopp-Schneider, Annette; Larribere, Lionel; Haberkorn, Uwe; Hassel, Jessica C; Dimitrakopoulou-Strauss, Antonia

2018-06-05

Immunotherapy has raised the issue of appropriate treatment response evaluation, due to the unique mechanism of action of the immunotherapeutic agents. Aim of this analysis is to evaluate the potential role of quantitative analysis of 2-deoxy-2-( 18 F)fluoro-D-glucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) data in monitoring of patients with metastatic melanoma undergoing ipilimumab therapy. 25 patients with unresectable metastatic melanoma underwent dynamic PET/CT (dPET/CT) of the thorax and upper abdomen as well as static, whole body PET/CT with 18 F-FDG before the start of ipilimumab treatment (baseline PET/CT), after two cycles of treatment (interim PET/CT) and at the end of treatment after four cycles (late PET/CT). The evaluation of dPET/CT studies was based on semi-quantitative (standardized uptake value, SUV) calculation as well as quantitative analysis, based on two-tissue compartment modeling and a fractal approach. Patients' best clinical response, assessed at a mean of 59 weeks, was used as reference. According to their best clinical response, patients were dichotomized in those demonstrating clinical benefit (CB, n = 16 patients) and those demonstrating no clinical benefit (no-CB, n = 9 patients). No statistically significant differences were observed between CB and no-CB regarding either semi-quantitative or quantitative parameters in all scans. On contrary, the application of the recently introduced PET response evaluation criteria for immunotherapy (PERCIMT) led to a correct classification rate of 84% (21/25 patients). Quantitative analysis of 18 F-FDG PET data does not provide additional information in treatment response evaluation of metastatic melanoma patients receiving ipilimumab. PERCIMT criteria correlated better with clinical response.

Evaluation of PET and laparoscopy in STagIng advanced gastric cancer: a multicenter prospective study (PLASTIC-study).

Science.gov (United States)

Brenkman, H J F; Gertsen, E C; Vegt, E; van Hillegersberg, R; van Berge Henegouwen, M I; Gisbertz, S S; Luyer, M D P; Nieuwenhuijzen, G A P; van Lanschot, J J B; Lagarde, S M; de Steur, W O; Hartgrink, H H; Stoot, J H M B; Hulsewe, K W E; Spillenaar Bilgen, E J; van Det, M J; Kouwenhoven, E A; van der Peet, D L; Daams, F; van Sandick, J W; van Grieken, N C T; Heisterkamp, J; van Etten, B; Haveman, J W; Pierie, J P; Jonker, F; Thijssen, A Y; Belt, E J T; van Duijvendijk, P; Wassenaar, E; van Laarhoven, H W M; Wessels, F J; Haj Mohammad, N; van Stel, H F; Frederix, G W J; Siersema, P D; Ruurda, J P

2018-04-20

Initial staging of gastric cancer consists of computed tomography (CT) and gastroscopy. In locally advanced (cT3-4) gastric cancer, fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT or PET) and staging laparoscopy (SL) may have a role in staging, but evidence is scarce. The aim of this study is to evaluate the impact and cost-effectiveness of PET and SL in addition to initial staging in patients with locally advanced gastric cancer. This prospective observational cohort study will include all patients with a surgically resectable, advanced gastric adenocarcinoma (cT3-4b, N0-3, M0), that are scheduled for treatment with curative intent after initial staging with gastroscopy and CT. The modalities to be investigated in this study is the addition of PET and SL. The primary outcome of this study is the proportion of patients in whom the PET or SL lead to a change in treatment strategy. Secondary outcome parameters are: diagnostic performance, morbidity and mortality, quality of life, and cost-effectiveness of these additional diagnostic modalities. The study recently started in August 2017 with a duration of 36 months. At least 239 patients need to be included in this study to demonstrate that the diagnostic modalities are break-even. Based on the annual number of gastrectomies in the participating centers, it is estimated that approximately 543 patients are included in this study. In this study, it is hypothesized that performing PET and SL for locally advanced gastric adenocarcinomas results in a change of treatment strategy in 27% of patients and an annual cost-reduction in the Netherlands of €916.438 in this patient group by reducing futile treatment. The results of this study may be applicable to all countries with comparable treatment algorithms and health care systems. NCT03208621 . This trial was registered prospectively on June 30, 2017.

Clinical Application of F-18 FDG PET (PET/CT) in Colo-rectal and Anal Cancer

International Nuclear Information System (INIS)

Kim, Byung Il

2008-01-01

In the management of colo-retal and anal cancer, accurate staging, treatment evaluation, early detection of recurrence are main clinical problems. F-18 FDG PET (PET/CT) has been reported as useful in the management of colo-rectal and anal cancer because that PET has high diagnostic performance comparing to conventional studies. In case of liver metastases, for confirmation of no extrahepatic metastases, in case of high risk of metastasis, for avoiding unnecessary operation, PET (PET/CT) is expected more useful. In anal cancer, PET is expected useful in lymph node staging. For the early prediction of chemotherapy or radiation therapy effect PET has been reported as useful, also. In early detection of recurrence by PET, cost-benefit advantages has been suggested, also. PET/CT is expected to have higher diagnostic performance than PET alone

Evaluation of focus laterality in temporal lobe epilepsy: a quantitative study comparing double inversion-recovery MR imaging at 3T with FDG-PET.

Science.gov (United States)

Morimoto, Emiko; Okada, Tomohisa; Kanagaki, Mitsunori; Yamamoto, Akira; Fushimi, Yasutaka; Matsumoto, Riki; Takaya, Shigetoshi; Ikeda, Akio; Kunieda, Takeharu; Kikuchi, Takayuki; Paul, Dominik; Miyamoto, Susumu; Takahashi, Ryosuke; Togashi, Kaori

2013-12-01

To quantitatively compare the diagnostic capability of double inversion-recovery (DIR) with F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of seizure focus laterality in temporal lobe epilepsy (TLE). This study was approved by the institutional review board, and written informed consent was obtained. Fifteen patients with TLE and 38 healthy volunteers were enrolled. All magnetic resonance (MR) images were acquired using a 3T-MRI system. Voxel-based analysis (VBA) was conducted for FDG-PET images and white matter segments of DIR images (DIR-WM) focused on the whole temporal lobe (TL) and the anterior part of the temporal lobe (ATL). Distribution of hypometabolic areas on FDG-PET and increased signal intensity areas on DIR-WM were evaluated, and their laterality was compared with clinically determined seizure focus laterality. Correct diagnostic rates of laterality were evaluated, and agreement between DIR-WM and FDG-PET was assessed using κ statistics. Increased signal intensity areas on DIR-WM were located at the vicinity of the hypometabolic areas on FDG-PET, especially in the ATL. Correct diagnostic rates of seizure focus laterality for DIR-WM (0.80 and 0.67 for the TL and the ATL, respectively) were slightly higher than those for FDG-PET (0.67 and 0.60 for the TL and the ATL, respectively). Agreement of laterality between DIR-WM and FDG-PET was substantial for the TL and almost perfect for the ATL (κ = 0.67 and 0.86, respectively). High agreement in localization between DIR-WM and FDG-PET and nearly equivalent detectability of them show us an additional role of MRI in TLE. Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.

Quantitative and Visual Assessments toward Potential Sub-mSv or Ultrafast FDG PET Using High-Sensitivity TOF PET in PET/MRI.

Science.gov (United States)

Behr, Spencer C; Bahroos, Emma; Hawkins, Randall A; Nardo, Lorenzo; Ravanfar, Vahid; Capbarat, Emily V; Seo, Youngho

2018-06-01

reduction in either injection dose for the same time or total scan time for the same injected dose. This "ultra-sensitivity" PET system provides a path to clinically acceptable extremely low-dose FDG PET studies (e.g., sub 1 mCi injection or sub-mSv effective dose) or PET studies as short as 1 min/bed (e.g., 6 min of total scan time) to cover whole body without compromising diagnostic performance.

Pet ownership and physical health.

Science.gov (United States)

Matchock, Robert L

2015-09-01

Pet ownership and brief human-animal interactions can serve as a form of social support and convey a host of beneficial psychological and physiological health benefits. This article critically examines recent relevant literature on the pet-health connection. Cross-sectional studies indicate correlations between pet ownership and numerous aspects of positive health outcomes, including improvements on cardiovascular measures and decreases in loneliness. Quasi-experimental studies and better controlled experimental studies corroborate these associations and suggest that owning and/or interacting with a pet may be causally related to some positive health outcomes. The value of pet ownership and animal-assisted therapy (AAT), as a nonpharmacological treatment modality, augmentation to traditional treatment, and healthy preventive behavior (in the case of pet ownership), is starting to be realized. However, more investigations that employ randomized controlled trials with larger sample sizes and investigations that more closely examine the underlying mechanism of the pet-health effect, such as oxytocin, are needed.

Optimization of PET-MR Registrations for Nonhuman Primates Using Mutual Information Measures: A Multi-Transform Method (MTM)

Science.gov (United States)

Sandiego, Christine M.; Weinzimmer, David; Carson, Richard E.

2012-01-01

An important step in PET brain kinetic analysis is the registration of functional data to an anatomical MR image. Typically, PET-MR registrations in nonhuman primate neuroreceptor studies used PET images acquired early post-injection, (e.g., 0–10 min) to closely resemble the subject’s MR image. However, a substantial fraction of these registrations (~25%) fail due to the differences in kinetics and distribution for various radiotracer studies and conditions (e.g., blocking studies). The Multi-Transform Method (MTM) was developed to improve the success of registrations between PET and MR images. Two algorithms were evaluated, MTM-I and MTM-II. The approach involves creating multiple transformations by registering PET images of different time intervals, from a dynamic study, to a single reference (i.e., MR image) (MTM-I) or to multiple reference images (i.e., MR and PET images pre-registered to the MR) (MTM-II). Normalized mutual information was used to compute similarity between the transformed PET images and the reference image(s) to choose the optimal transformation. This final transformation is used to map the dynamic dataset into the animal’s anatomical MR space, required for kinetic analysis. The chosen transformed from MTM-I and MTM-II were evaluated using visual rating scores to assess the quality of spatial alignment between the resliced PET and reference. One hundred twenty PET datasets involving eleven different tracers from 3 different scanners were used to evaluate the MTM algorithms. Studies were performed with baboons and rhesus monkeys on the HR+, HRRT, and Focus-220. Successful transformations increased from 77.5%, 85.8%, to 96.7% using the 0–10 min method, MTM-I, and MTM-II, respectively, based on visual rating scores. The Multi-Transform Methods proved to be a robust technique for PET-MR registrations for a wide range of PET studies. PMID:22926293

Present and future of PET and PET/CT in gynaecologic malignancies

International Nuclear Information System (INIS)

Musto, Alessandra; Rampin, Lucia; Nanni, Cristina; Marzola, Maria Cristina; Fanti, Stefano; Rubello, Domenico

2011-01-01

Objectives: To review the published data in literature on patients affected by gynaecological malignancies to establish the role of 18 F-FDG positron emission tomography (PET) and PET/CT in comparison to conventional imaging (CI). Materials and methods: All papers specifically addressed to the role of 18 F-FDG PET and PET/CT in gynaecological malignancies published on PubMed/Medline, in abstracts from the principal international congresses, in the guidelines from national Societies that had appeared in literature until November 2009 were considered for the purpose of the present study. Results and conclusions: The use of 18 F-FDG PET, and even more of 18 F-FDG PET/CT, is increasing in the follow up of patients with gynaecologic malignancies and suspected recurrent disease: there is evidence in the literature that 18 F-FDG PET/CT has a higher sensitivity than CI in depicting occult metastatic spread. An interesting issue is represented by patients with ovarian cancer with an increase of the specific biomarker, CA-125, and negative/inconclusive findings at CI. The use of 18 F-FDG PET in differential diagnosis and staging is more controversial, but there is some evidence that a baseline PET examination performed before commencing therapy, for staging purpose, is also useful to evaluate the response to chemoradiation treatment. In several papers it has been suggested a relevant role of 18 F-FDG PET/CT in evaluating the entity of response to treatment and therefore to plan the subsequent therapeutic strategy.

Additional value of PET-CT in the staging of lung cancer: comparison with CT alone, PET alone and visual correlation of PET and CT

International Nuclear Information System (INIS)

Wever, W. de; Marchal, G.; Bogaert, J.; Verschakelen, J.A.; Ceyssens, S.; Mortelmans, L.; Stroobants, S.

2007-01-01

Integrated positron emission tomography (PET) and computed tomography (CT) is a new imaging modality offering anatomic and metabolic information. The purpose was to evaluate retrospectively the accuracy of integrated PET-CT in the staging of a suggestive lung lesion, comparing this with the accuracy of CT alone, PET alone and visually correlated PET-CT. Fifty patients undergoing integrated PET-CT for staging of a suggestive lung lesion were studied. Their tumor, node, metastasis (TNM) statuses were determined with CT, PET, visually correlated PET-CT and integrated PET-CT. These TNM stages were compared with the surgical TNM status. Integrated PET-CT was the most accurate imaging technique in the assessment of the TNM status. Integrated PET-CT predicted correctly the T status, N status, M status and TNM status in, respectively, 86%, 80%, 98%, 70% versus 68%, 66%,88%, 46% with CT, 46%, 70%, 96%, 30% with PET and 72%, 68%, 96%, 54% with visually correlated PET-CT. T status and N status were overstaged, respectively, in 8% and 16% with integrated PET-CT, in 20% and 28% with CT, in 16% and 20% with PET, in 12% and 20% with visually correlated PET-CT and understaged in 6% and 4% with integrated PET-CT, versus 12% and 6% with CT, 38% and 10% with PET and 12% with visually correlated PET-CT. Integrated PET-CT improves the staging of lung cancer through a better anatomic localization and characterization of lesions and is superior to CT alone and PET alone. If this technique is not available, visual correlation of PET and CT can be a valuable alternative. (orig.)

Influence of PSA, PSA velocity and PSA doubling time on contrast-enhanced 18F-choline PET/CT detection rate in patients with rising PSA after radical prostatectomy

International Nuclear Information System (INIS)

Schillaci, Orazio; Calabria, Ferdinando; Tavolozza, Mario; Caracciolo, Cristiana Ragano; Orlacchio, Antonio; Danieli, Roberta; Simonetti, Giovanni; Agro, Enrico Finazzi; Miano, Roberto

2012-01-01

To evaluate the accuracy of contrast-enhanced 18 F-choline PET/CT in restaging patients with prostate cancer after radical prostatectomy in relation to PSA, PSA velocity (PSAve) and PSA doubling time (PSAdt). PET/CT was performed in 49 patients (age range 58-87 years) with rising PSA (mean 4.13 ng/ml) who were divided in four groups according to PSA level: ≤1 ng/ml, 1 to ≤2 ng/ml, 2 to ≤4 ng/ml, and >4 ng/ml. PSAve and PSAdt were measured. PET and CT scans were interpreted separately and then together. PET/CT diagnosed relapse in 33 of the 49 patients (67%). The detection rates were 20%, 55%, 80% and 87% in the PSA groups ≤1, 1 to ≤2, 2 to ≤4 and >4 ng/ml, respectively. PET/CT was positive in 7 of 18 patients (38.9%) with a PSA ≤2 ng/ml, and in 26 of 31 (83.9%) with a PSA >2 ng/ml. PET/CT was positive in 7 of 25 patients (84%) with PSAdt ≤6 months, and in 12 of 24 patients (50%) with PSAdt >6 months, and was positive in 26 of 30 patients (86%) with a PSAve >2 ng/ml per year, and in 7 of 19 patients (36.8%) with PSAve ≤2 ng/ml per year. PET alone was positive in 31 of 49 patients (63.3%), and of these 31 patients, CT was negative in 14 but diagnosed bone lesions in 2 patients in whom PET alone was negative. CT with the administration of intravenous contrast medium did not provide any further information. Detection rate of 18 F-choline imaging is closely related to PSA and PSA kinetics. In particular, 18 F-choline PET/CT is recommended in patients with PSA >2 ng/ml, PSAdt ≤6 months and PSAve >2 ng/ml per year. CT is useful for detecting bone metastases that are not 18 F-choline-avid. The use of intravenous contrast agent seems unnecessary. (orig.)

11C-MET PET/MRI for detection of recurrent glioma.

Science.gov (United States)

Deuschl, C; Kirchner, J; Poeppel, T D; Schaarschmidt, B; Kebir, S; El Hindy, N; Hense, J; Quick, H H; Glas, M; Herrmann, K; Umutlu, L; Moenninghoff, C; Radbruch, A; Forsting, M; Schlamann, M

2018-04-01

Radiological assessment of brain tumors is widely based on the Radiology Assessment of Neuro-Oncology (RANO) criteria that consider non-specific T1 and T2 weighted images. Limitation of the RANO criteria is that they do not include metabolic imaging techniques that have been reported to be helpful to differentiate treatment related changes from true tumor progression. In the current study, we assessed if the combined use of MRI and PET with hybrid 11 C-MET PET/MRI can improve diagnostic accuracy and diagnostic confidence of the readers to differentiate treatment related changes from true progression in recurrent glioma. Fifty consecutive patients with histopathologically proven glioma were prospectively enrolled for a hybrid 11 C-MET PET/MRI to differentiate recurrent glioma from treatment induced changes. Sole MRI data were analyzed based on RANO. Sole PET data and in a third evaluation hybrid 11 C-MET-PET/MRI data were assessed for metabolic respectively metabolic and morphologic glioma recurrence. Diagnostic performance and diagnostic confidence of the reader were calculated for the different modalities, and the McNemar test and Mann-Whitney U Test were applied for statistical analysis. Hybrid 11 C-MET PET/MRI was successfully performed in all 50 patients. Glioma recurrence was diagnosed in 35 of the 50 patients (70%). Sensitivity and specificity were calculated for MRI (86.11% and 71.43%), for 11 C-MET PET (96.77% and 73.68%), and for hybrid 11 C-MET-PET/MRI (97.14% and 93.33%). For diagnostic accuracy hybrid 11 C-MET-PET/MRI (96%) showed significantly higher values than MRI alone (82%), whereas no significant difference was found for 11C-MET PET (88%). Furthermore, by rating on a five-point Likert scale significantly higher scores were found for diagnostic confidence when comparing 11 C-MET PET/MRI (4.26 ± 0,777) to either PET alone (3.44 ± 0.705) or MRI alone (3.56 ± 0.733). This feasibility study showed that hybrid PET/MRI might strengthen

Selective Nodal Irradiation on Basis of 18FDG-PET Scans in Limited-Disease Small-Cell Lung Cancer: A Prospective Study

International Nuclear Information System (INIS)

Loon, Judith van; De Ruysscher, Dirk; Wanders, Rinus; Boersma, Liesbeth; Simons, Jean; Oellers, Michel; Dingemans, Anne-Marie C.; Hochstenbag, Monique; Bootsma, Gerben; Geraedts, Wiel; Pitz, Cordula; Teule, Jaap; Rhami, Ali; Thimister, Willy; Snoep, Gabriel; Dehing-Oberije, Cary; Lambin, Philippe

2010-01-01

Purpose: To evaluate the results of selective nodal irradiation on basis of 18 F-deoxyglucose positron emission tomography (PET) scans in patients with limited-disease small-cell lung cancer (LD-SCLC) on isolated nodal failure. Methods and Materials: A prospective study was performed of 60 patients with LD-SCLC. Radiotherapy was given to a dose of 45 Gy in twice-daily fractions of 1.5 Gy, concurrent with carboplatin and etoposide chemotherapy. Only the primary tumor and the mediastinal lymph nodes involved on the pretreatment PET scan were irradiated. A chest computed tomography (CT) scan was performed 3 months after radiotherapy completion and every 6 months thereafter. Results: A difference was seen in the involved nodal stations between the pretreatment 18 F-deoxyglucose PET scans and computed tomography scans in 30% of patients (95% confidence interval, 20-43%). Of the 60 patients, 39 (65%; 95% confidence interval [CI], 52-76%) developed a recurrence; 2 patients (3%, 95% CI, 1-11%) experienced isolated regional failure. The median actuarial overall survival was 19 months (95% CI, 17-21). The median actuarial progression-free survival was 14 months (95% CI, 12-16). 12% (95% CI, 6-22%) of patients experienced acute Grade 3 (Common Terminology Criteria for Adverse Events, version 3.0) esophagitis. Conclusion: PET-based selective nodal irradiation for LD-SCLC resulted in a low rate of isolated nodal failures (3%), with a low percentage of acute esophagitis. These findings are in contrast to those from our prospective study of CT-based selective nodal irradiation, which resulted in an unexpectedly high percentage of isolated nodal failures (11%). Because of the low rate of isolated nodal failures and toxicity, we believe that our data support the use of PET-based SNI for LD-SCLC.

Early clinical experience and impact of 18F-FDG PET

DEFF Research Database (Denmark)

Gutte, Henrik; Højgaard, Liselotte; Kjaer, Andreas

2005-01-01

PURPOSE: To determine the influence and impact of [F]- fluorodeoxyglucose positron emission tomography (FDG PET) in Denmark. METHODS: A standardized questionnaire was sent to the referring physicians of 743 consecutive cases between January 2000 and December 2001. The questionnaire was designed...... to determine whether and how the results of the FDG PET imaging changed patient management. RESULTS: The response rate was 71% (524 responded). The distribution of all responding physicians included 26 different specialities. The majority were from haematology (23%), oncology (20%), plastic surgery (17...... confirmed the diagnosis, helped staging, changed treatment plan or confirmed treatment of choice. Physicians indicated a general satisfaction with FDG PET imaging in 86% of the cases. CONCLUSION: This survey-based study indicates that FDG PET imaging has a major impact on patient management, contributing...

Hybrid FDG-PET/MR compared to FDG-PET/CT in adult lymphoma patients.

Science.gov (United States)

Atkinson, Wendy; Catana, Ciprian; Abramson, Jeremy S; Arabasz, Grae; McDermott, Shanaugh; Catalano, Onofrio; Muse, Victorine; Blake, Michael A; Barnes, Jeffrey; Shelly, Martin; Hochberg, Ephraim; Rosen, Bruce R; Guimaraes, Alexander R

2016-07-01

The goal of this study is to evaluate the diagnostic performance of simultaneous FDG-PET/MR including diffusion compared to FDG-PET/CT in patients with lymphoma. Eighteen patients with a confirmed diagnosis of non-Hodgkin's (NHL) or Hodgkin's lymphoma (HL) underwent an IRB-approved, single-injection/dual-imaging protocol consisting of a clinical FDG-PET/CT and subsequent FDG-PET/MR scan. PET images from both modalities were reconstructed iteratively. Attenuation correction was performed using low-dose CT data for PET/CT and Dixon-MR sequences for PET/MR. Diffusion-weighted imaging was performed. SUVmax was measured and compared between modalities and the apparent diffusion coefficient (ADC) using ROI analysis by an experienced radiologist using OsiriX. Strength of correlation between variables was measured using the Pearson correlation coefficient (r p). Of the 18 patients included in this study, 5 had HL and 13 had NHL. The median age was 51 ± 14.8 years. Sixty-five FDG-avid lesions were identified. All FDG-avid lesions were visible with comparable contrast, and therefore initial and follow-up staging was identical between both examinations. SUVmax from FDG-PET/MR [(mean ± sem) (21.3 ± 2.07)] vs. FDG-PET/CT (mean 23.2 ± 2.8) demonstrated a strongly positive correlation [r s = 0.95 (0.94, 0.99); p < 0.0001]. There was no correlation found between ADCmin and SUVmax from FDG-PET/MR [r = 0.17(-0.07, 0.66); p = 0.09]. FDG-PET/MR offers an equivalent whole-body staging examination as compared with PET/CT with an improved radiation safety profile in lymphoma patients. Correlation of ADC to SUVmax was weak, understating their lack of equivalence, but not undermining their potential synergy and differing importance.

Temporal lobe dysfunction in childhood autism: a PET study

International Nuclear Information System (INIS)

Boddaert, N.; Poline, J.B.; Brunelle, F.; Zilbovicius, M.; Boddaert, N.; Brunelle, F.; Chabane, N.; Barthelemy, C.; Zilbovicius, M.; Bourgeois, M.; Samson, Y.

2002-01-01

Childhood autism is a severe developmental disorder that impairs the acquisition of some of the most important skills in human life. Progress in understanding the neural basis of childhood autism requires clear and reliable data indicating specific neuro-anatomical or neuro-physiological abnormalities. The purpose of the present study was to research localized brain dysfunction in autistic children using functional brain imaging. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET) in 21 primary autistic children and 10 age-matched non autistic children. A statistical parametric analysis of rCBF images revealed significant bilateral temporal hypoperfusion in the associative auditory cortex (superior temporal gyrus) and in the multimodal cortex (superior temporal sulcus) in the autistic group (p<0.001). In addition, temporal hypoperfusion was detected individually in 77% of autistic children. These findings provide robust evidence of well localized functional abnormalities in autistic children located in the superior temporal lobe. Such localized abnormalities were not detected with the low resolution PET camera (14-22). This study suggests that high resolution PET camera combined with statistical parametric mapping is useful to understand developmental disorders. (authors)

Influence of the clay in the stress cracking resistance of PET

International Nuclear Information System (INIS)

Teofilo, Edvania T.; Silva, Emanuela S.; Silva, Suedina M.L.; Rabello, Marcelo S.

2011-01-01

The environmental stress cracking resistance in PET and hybrid PET/clay were conducted under stress relaxation test. X-ray diffraction analysis show that was obtained immiscible system. In the absence of aggressive fluids the hybrid exhibited higher relaxation rates than the PET. Already in contact with aggressive fluids showed a similar or lower relaxation rate than the PET, being more resistant. Suggesting that the clay, though not interlayer, interferes with the distribution of the stress cracking agent. Thus, the barrier effect caused by the clay was more significant than the stress concentration caused by it. (author)

Imaging with {sup 124}I in differentiated thyroid carcinoma: is PET/MRI superior to PET/CT?

Energy Technology Data Exchange (ETDEWEB)

Binse, I.; Poeppel, T.D.; Ruhlmann, M.; Gomez, B.; Bockisch, A.; Rosenbaum-Krumme, S.J. [University of Duisburg-Essen, Medical Faculty, Department of Nuclear Medicine, Essen (Germany); Umutlu, L. [University of Duisburg-Essen, Medical Faculty, Department of Radiology, Essen (Germany)

2016-06-15

The aim of this study was to compare integrated PET/CT and PET/MRI for their usefulness in detecting and categorizing cervical iodine-positive lesions in patients with differentiated thyroid cancer using {sup 124}I as tracer. The study group comprised 65 patients at high risk of iodine-positive metastasis who underwent PET/CT (low-dose CT scan, PET acquisition time 2 min; PET/CT{sub 2}) followed by PET/MRI of the neck 24 h after {sup 124}I administration. PET images from both modalities were analysed for the numbers of tracer-positive lesions. Two different acquisition times were used for the comparisons, one matching the PET/CT{sub 2} acquisition time (2 min, PET/MRI{sub 2}) and the other covering the whole MRI scan time (30 min, PET/MRI{sub 30}). Iodine-positive lesions were categorized as metastasis, thyroid remnant or inconclusive according to their location on the PET/CT images. Morphological information provided by MRI was considered for evaluation of lesions on PET/MRI and for volume information. PET/MRI{sub 2} detected significantly more iodine-positive metastases and thyroid remnants than PET/CT{sub 2} (72 vs. 60, p = 0.002, and 100 vs. 80, p = 0.001, respectively), but the numbers of patients with at least one tumour lesion identified were not significantly different (21/65 vs. 17/65 patients). PET/MRI{sub 30} tended to detect more PET-positive metastases than PET/MRI{sub 2} (88 vs. 72), but the difference was not significant (p = 0.07). Of 21 lesions classified as inconclusive on PET/CT, 5 were assigned to metastasis or thyroid remnant when evaluated by PET/MRI. Volume information was available in 34 % of iodine-positive metastases and 2 % of thyroid remnants on PET/MRI. PET/MRI of the neck was found to be superior to PET/CT in detecting iodine-positive lesions. This was attributed to the higher sensitivity of the PET component, Although helpful in some cases, we found no substantial advantage of PET/MRI over PET/CT in categorizing iodine

List mode reconstructions for PET with motion compensation: A simulation study

International Nuclear Information System (INIS)

Qi, Jinyi; Huesman, Ronald H.

2002-01-01

Motion artifacts can be a significant factor that limits the image quality in high-resolution PET. Surveillance systems have been developed to track the movements of the subject during a scan. Development of reconstruction algorithms that are able to compensate for the subject motion will increase the potential of PET. In this paper we present a list mode likelihood reconstruction algorithm with the ability of motion compensation. The subject motion is explicitly modeled in the likelihood function. The detections of each detector pair are modeled as a Poisson process with time-varying rate function. The proposed method has several advantages over the existing methods. It uses all detected events and does not introduce any interpolation error. Computer simulations show that the proposed method can compensate simulated subject movements and that the reconstructed images have no visible motion artifacts

Role of FDG-PET and PET/CT in the diagnosis of prolonged febrile states

International Nuclear Information System (INIS)

Jaruskova, M.; Belohlavek, O.

2006-01-01

The role of FDG-PET and PET/CT in patients whose main symptom is prolonged fever has not yet been defined. We addressed this topic in a retrospective study. A total of 124 patients (referred between May 2001 and December 2004) with fever of unknown origin or prolonged fever due to a suspected infection of a joint or vascular prosthesis were included in the study. The patients underwent either FDG-PET or FDG-PET/CT scanning. Sixty-seven patients had a negative focal FDG-PET finding; in this group the method was regarded as unhelpful in determining a diagnosis, and no further investigation was pursued. We tried to obtain clinical confirmation for all patients with positive PET findings. Fifty-seven (46%) patients had positive FDG-PET findings. In six of them no further clinical information was available. Fifty-one patients with positive PET findings and 118 patients in total were subsequently evaluated. Systemic connective tissue disease was confirmed in 17 patients, lymphoma in three patients, inflammatory bowel disease in two patients, vascular prosthesis infection in seven patients, infection of a hip or knee replacement in seven patients, mycotic aneurysm in two patients, abscess in four patients and AIDS in one patient. In eight (16%) patients the finding was falsely positive. FDG-PET or PET/CT contributed to establishing a final diagnosis in 84% of the 51 patients with positive PET findings and in 36% of all 118 evaluated patients with prolonged fever. (orig.)

Comparative study of FDG-PET and sestamibi-SPECT in the diagnosis of secondary hyperparathyroidism

International Nuclear Information System (INIS)

Higuchi, T.; Ozawa, K.; Oriuchi, N.; Khan, N.; Endo, K.; Otake, H.; Matsubara, K.

2002-01-01

Aim: FDG-PET is reported to be more accurate in preoperative localization of hyper functioning parathyroid gland of primary hyperparathyroidism in comparison with sestamibi-SPECT by Neumann et al. However, its usefulness in the diagnosis of secondary hyperparathyroidism has not been reported yet. In this study, we've performed the direct comparison of the usefulness of FDG-PET and sestamibi-SPECT in the detection of abnormal parathyroid tissue in the patients of secondary hyperparathyroidism under hemodilysis. Material and Methods: One primary and 5 secondary hyperparathyroidism patients underwent FDG-PET and sestamibi-SPECT. After overnight fasting, 300 to 400 MBq of FDG was intravenously injected, followed by whole body PET image acquisition after 50 minutes. In the same day before FDG-PET, 600 MBq of sestamibi was injected and early and delayed planar image and delayed SPECT image has been obtained. Visual interpretation of the abnormal parathyroid uptake has been performed by 2 experienced nuclear physician independently. Results: In the secondary cases, FDG-PET shows no hyper functioning gland in all 5 cases, whereas sestamibi-SPECT shows 8 hyper functioning glands. In contrast, hyper functioning gland of the primary hyperparathyroidism case has been clearly visualized only by FDG-PET. Conclusion: Although FDG-PET is very useful in detecting hyper functioning gland in primary hyperparathyroidism, it is not useful in secondary hyperparathyroidism. Further pathological analysis about the different glucose metabolism of primary and secondary hyper functioning gland should be added in the future study

An update on the role of PET/CT and PET/MRI in ovarian cancer

International Nuclear Information System (INIS)

Khiewvan, Benjapa; Torigian, Drew A.; Emamzadehfard, Sahra; Paydary, Koosha; Salavati, Ali; Houshmand, Sina; Werner, Thomas J.; Alavi, Abass

2017-01-01

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as 18 F-fluorothymidine (FLT) or 11 C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer. (orig.)

An update on the role of PET/CT and PET/MRI in ovarian cancer

Energy Technology Data Exchange (ETDEWEB)

Khiewvan, Benjapa [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Mahidol University, Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok (Thailand); Torigian, Drew A.; Emamzadehfard, Sahra; Paydary, Koosha; Salavati, Ali; Houshmand, Sina; Werner, Thomas J.; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States)

2017-06-15

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as {sup 18}F-fluorothymidine (FLT) or {sup 11}C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer. (orig.)

18F-FDOPA PET/CT imaging of insulinoma revisited

International Nuclear Information System (INIS)

Imperiale, Alessio; Namer, Izzie-Jacques; Sebag, Frederic; Vix, Michel; Castinetti, Frederic; Kessler, Laurence; Moreau, Francois; Bachellier, Philippe; Guillet, Benjamin; Mundler, Olivier; Taieb, David

2015-01-01

18 F-FDOPA PET imaging is increasingly used in the work-up of patients with neuroendocrine tumours. It has been shown to be of limited value in localizing pancreatic insulin-secreting tumours in adults with hyperinsulinaemic hypoglycaemia (HH) mainly due to 18 F-FDOPA uptake by the whole pancreatic gland. The objective of this study was to review our experience with 18 F-FDOPA PET/CT imaging with carbidopa (CD) premedication in patients with HH in comparison with PET/CT studies performed without CD premedication in an independent population. A retrospective study including 16 HH patients who were investigated between January 2011 and December 2013 using 18 F-FDOPA PET/CT (17 examinations) in two academic endocrine tumour centres was conducted. All PET/CT examinations were performed under CD premedication (200 mg orally, 1 - 2 h prior to tracer injection). The PET/CT acquisition protocol included an early acquisition (5 min after 18 F-FDOPA injection) centred over the upper abdomen and a delayed whole-body acquisition starting 20 - 30 min later. An independent series of eight consecutive patients with HH and investigated before 2011 were considered for comparison. All patients had a reference whole-body PET/CT scan performed about 1 h after 18 F-FDOPA injection. In all cases, PET/CT was performed without CD premedication. In the study group, 18 F-FDOPA PET/CT with CD premedication was positive in 8 out of 11 patients with histologically proven insulinoma (73 %). All 18 F-FDOPA PET/CT-avid insulinomas were detected on early images and 5 of 11 (45 %) on delayed ones. The tumour/normal pancreas uptake ratio was not significantly different between early and delayed acquisitions. Considering all patients with HH, including those without imaging evidence of disease, the detection rate of the primary lesions using CD-assisted 18 F-FDOPA PET/CT was 53 %, showing 9 insulinomas in 17 studies performed. In the control group (without CD premedication, eight patients), the final

Y-90 PET imaging for radiation theragnosis using bootstrap event re sampling

International Nuclear Information System (INIS)

Nam, Taewon; Woo, Sangkeun; Min, Gyungju; Kim, Jimin; Kang, Joohyun; Lim, Sangmoo; Kim, Kyeongmin

2013-01-01

Surgical resection is the most effective method to recover the liver function. However, Yttrium-90 (Y-90) has been used as a new treatment due to the fact that it can be delivered to the tumors and results in greater radiation exposure to the tumors than using external radiation nowadays since most treatment is palliative in case of unresectable stage of hepatocellular carcinoma (HCC). Recently, Y-90 has been received much interest and studied by many researchers. Imaging of Y-90 has been conducted using most commonly gamma camera but PET imaging is required due to low sensitivity and resolution. The purpose of this study was to assess statistical characteristics and to improve count rate of image for enhancing image quality by using nonparametric bootstrap method. PET data was able to be improved using non-parametric bootstrap method and it was verified with showing improved uniformity and SNR. Uniformity showed more improvement under the condition of low count rate, i.e. Y-90, in case of phantom and also uniformity and SNR showed improvement of 15.6% and 33.8% in case of mouse, respectively. Bootstrap method performed in this study for PET data increased count rate of PET image and consequentially time for acquisition time can be reduced. It will be expected to improve performance for diagnosis

Imaging corn plants with PhytoPET, a modular PET system for plant biology

Energy Technology Data Exchange (ETDEWEB)

Lee, S.; Kross, B.; McKisson, J.; McKisson, J. E.; Weisenberger, A. G.; Xi, W.; Zorn, C.; Bonito, G.; Howell, C. R.; Reid, C. D.; Crowell, A.; Cumberbatch, L. C.; Topp, C.; Smith, M. F.

2013-11-01

PhytoPET is a modular positron emission tomography (PET) system designed specifically for plant imaging. The PhytoPET design allows flexible arrangements of PET detectors based on individual standalone detector modules built from single Hamamatsu H8500 position sensitive photomultiplier tubes and pixelated LYSO arrays. We have used the PhytoPET system to perform preliminary corn plant imaging studies at the Duke University Biology Department Phytotron. Initial evaluation of the PhytoPET system to image the biodistribution of the positron emitting tracer {sup 11}C in corn plants is presented. {sup 11}CO{sub 2} is loaded into corn seedlings by a leaf-labeling cuvette and translocation of {sup 11}C-sugars is imaged by a flexible arrangement of PhytoPET modules on each side. The PhytoPET system successfully images {sup 11}C within corn plants and allows for the dynamic measurement of {sup 11}C-sugar translocation from the leaf to the roots.

FDG PET and PET-CT for the detection of bone metastases in patients with head and neck cancer. A meta-analysis

International Nuclear Information System (INIS)

Yi, Xuelin; Zhang, Hongting; Liu, Shixi; Fan, Min; Liu, Yilin

2013-01-01

We performed a meta-analysis to evaluate 18FDG PET/PET-CT for the detection of bone metastases in patients with head and neck cancer. We calculated sensitivities, specificities, likelihood ratios, and constructed summary receiver operating characteristic curves for PET and PET-CT, respectively. We also compared the performance of PET/PET-CT with that of bone scintigraphy by analysing studies that had also used bone scintigraphy on the same patients. Across 9 PET studies (1621 patients) and 10 PET-CT studies (1291 patients), sensitivity and specificity of PET were 0.81 and 0.99, and of PET-CT were 0.89 and 0.99, respectively. In 5 comparative studies (1184 patients), sensitivity and specificity of PET/PET-CT were 0.85 and 0.98, and of bone scintigraphy were 0.55 and 0.98, respectively. 18FDG PET and PET-CT have high sensitivity and accuracy for the detection of bone metastasis in patients with head and neck cancer.

Extraction of left ventricular myocardial mass from dynamic 11C-acetate PET

DEFF Research Database (Denmark)

Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik

Background: Dynamic 11C-acetate PET is used to quantify oxygen metabolism, which is used to calculate left ventricular (LV) myocardial efficiency, an early marker of heart failure. This requires estimation of LV myocardial mass and is typically derived from a separate cardiovascular magnetic...... resonance (CMR) scan. The aim of this study was to explore the feasibility of estimating myocardial mass directly from a dynamic 11C-acetate PET scan. Methods: 21 subjects underwent a 27-min 11C-acetate PET scan on a Siemens Biograph TruePoint 64 PET/CT scanner. In addition, 10 subjects underwent a dynamic...... 11C-acetate 27-min PET scan on a GE Discovery ST PET/CT scanner. Parametric images of uptake rate K1 and both arterial (VA) and venous (VV) spillover fractions were generated using a basis function implementation of the standard single tissue compartment model using non-gated dynamic data. The LV...

Dynamic respiratory gated 18FDG-PET of lung tumors - a feasibility study

International Nuclear Information System (INIS)

Skjei Knudtsen, Ingerid; Skretting, Arne; Roedal, Jan; Brustugun, Odd Terje; Helland, Aaslaug; Malinen, Eirik

2011-01-01

Background. 18 FDG-PET/CT imaging is well established for diagnosis and staging of lung tumors. However, more detailed information regarding the distribution of FDG within the tumor, also as a function of time after injection may be relevant. In this study we explore the feasibility of a combined dynamic and respiratory gated (DR) PET protocol. Material and methods. A DR FDG-PET protocol for a Siemens Biograph 16 PET/CT scanner was set up, allowing data acquisition from the time of FDG injection. Breath-hold (BH) respiratory gating was performed at four intervals over a total acquisition time of 50 minutes. Thus, the PET protocol provides both motion-free images and a spatiotemporal characterization of the glucose distribution in lung tumors. Software tools were developed in-house for tentative tumor segmentation and for extracting standard uptake values (SUVs) voxel by voxel, tumor volumes and SUV gradients in all directions. Results. Four pilot patients have been investigated with the DR PET protocol. The procedure was well tolerated by the patients. The BH images appeared sharper, and SUV max /SUV mean was higher, compared to free breathing (FB) images. Also, SUV gradients in the periphery of the tumor in the BH images were in general greater than or equal to the gradients in the FB PET images. Conclusion. The DR FDG-PET protocol is feasible and the BH images have a superior quality compared to the FB images. The protocol may also provide information of relevance for radiotherapy planning and follow-up. A patient trial is needed for assessing the clinical value of the imaging protocol

Improving PET Quantification of Small Animal [68Ga]DOTA-Labeled PET/CT Studies by Using a CT-Based Positron Range Correction.

Science.gov (United States)

Cal-Gonzalez, Jacobo; Vaquero, Juan José; Herraiz, Joaquín L; Pérez-Liva, Mailyn; Soto-Montenegro, María Luisa; Peña-Zalbidea, Santiago; Desco, Manuel; Udías, José Manuel

2018-01-19

Image quality of positron emission tomography (PET) tracers that emits high-energy positrons, such as Ga-68, Rb-82, or I-124, is significantly affected by positron range (PR) effects. PR effects are especially important in small animal PET studies, since they can limit spatial resolution and quantitative accuracy of the images. Since generators accessibility has made Ga-68 tracers wide available, the aim of this study is to show how the quantitative results of [ 68 Ga]DOTA-labeled PET/X-ray computed tomography (CT) imaging of neuroendocrine tumors in mice can be improved using positron range correction (PRC). Eighteen scans in 12 mice were evaluated, with three different models of tumors: PC12, AR42J, and meningiomas. In addition, three different [ 68 Ga]DOTA-labeled radiotracers were used to evaluate the PRC with different tracer distributions: [ 68 Ga]DOTANOC, [ 68 Ga]DOTATOC, and [ 68 Ga]DOTATATE. Two PRC methods were evaluated: a tissue-dependent (TD-PRC) and a tissue-dependent spatially-variant correction (TDSV-PRC). Taking a region in the liver as reference, the tissue-to-liver ratio values for tumor tissue (TLR tumor ), lung (TLR lung ), and necrotic areas within the tumors (TLR necrotic ) and their respective relative variations (ΔTLR) were evaluated. All TLR values in the PRC images were significantly different (p DOTA-labeled PET/CT imaging of mice with neuroendocrine tumors, hence demonstrating that these techniques could also ameliorate the deleterious effect of the positron range in clinical PET imaging.

Present and future of PET and PET/CT in gynaecologic malignancies

Energy Technology Data Exchange (ETDEWEB)

Musto, Alessandra [Department of Nuclear Medicine, PET Center, Policlinico Sant' Orsola Malpighi, Bologna University, Bologna (Italy); Rampin, Lucia [Department of Nuclear Medicine, PET Center, Radiology, Medical Physics, Santa Maria della Misericordia Hospital, viale tre martiri 140, 45100 Rovigo (Italy); Nanni, Cristina [Department of Nuclear Medicine, PET Center, Policlinico Sant' Orsola Malpighi, Bologna University, Bologna (Italy); Marzola, Maria Cristina [Department of Nuclear Medicine, PET Center, Radiology, Medical Physics, Santa Maria della Misericordia Hospital, viale tre martiri 140, 45100 Rovigo (Italy); Fanti, Stefano [Department of Nuclear Medicine, PET Center, Policlinico Sant' Orsola Malpighi, Bologna University, Bologna (Italy); Rubello, Domenico, E-mail: domenico.rubello@libero.it [Department of Nuclear Medicine, PET Center, Radiology, Medical Physics, Santa Maria della Misericordia Hospital, viale tre martiri 140, 45100 Rovigo (Italy)

2011-04-15

Objectives: To review the published data in literature on patients affected by gynaecological malignancies to establish the role of {sup 18}F-FDG positron emission tomography (PET) and PET/CT in comparison to conventional imaging (CI). Materials and methods: All papers specifically addressed to the role of {sup 18}F-FDG PET and PET/CT in gynaecological malignancies published on PubMed/Medline, in abstracts from the principal international congresses, in the guidelines from national Societies that had appeared in literature until November 2009 were considered for the purpose of the present study. Results and conclusions: The use of {sup 18}F-FDG PET, and even more of {sup 18}F-FDG PET/CT, is increasing in the follow up of patients with gynaecologic malignancies and suspected recurrent disease: there is evidence in the literature that {sup 18}F-FDG PET/CT has a higher sensitivity than CI in depicting occult metastatic spread. An interesting issue is represented by patients with ovarian cancer with an increase of the specific biomarker, CA-125, and negative/inconclusive findings at CI. The use of {sup 18}F-FDG PET in differential diagnosis and staging is more controversial, but there is some evidence that a baseline PET examination performed before commencing therapy, for staging purpose, is also useful to evaluate the response to chemoradiation treatment. In several papers it has been suggested a relevant role of {sup 18}F-FDG PET/CT in evaluating the entity of response to treatment and therefore to plan the subsequent therapeutic strategy.

The MiniPET: a didactic PET system

International Nuclear Information System (INIS)

Pedro, R; Silva, J; Maio, A; Gurriana, L; Silva, J M; Augusto, J Soares

2013-01-01

The MiniPET project aims to design and build a small PET system. It consists of two 4 × 4 matrices of 16 LYSO scintillator crystals and two PMTs with 16 channels resulting in a low cost system with the essential functionality of a clinical PET instrument. It is designed to illustrate the physics of the PET technique and to provide a didactic platform for the training of students and nuclear imaging professionals as well as for scientific outreach. The PET modules can be configured to test for the coincidence of 511 keV gamma rays. The model has a flexible mechanical setup [1] and can simulate 14 diferent ring geometries, from a configuration with as few as 18 detectors per ring (ring radius φ=51 mm), up to a geometry with 70 detectors per ring (φ=200 mm). A second version of the electronic system [2] allowed measurement and recording of the energy deposited in 4 detector channels by photons from a 137 Cs radioactive source and by photons resulting of the annihilation of positrons from a 22 Na radioactive source. These energy spectra are used for detector performance studies, as well as angular dependency studies. In this paper, the mechanical setup, the front-end high-speed analog electronics, the digital acquisition and control electronics implemented in a FPGA, as well as the data-transfer interface between the FPGA board and a host PC are described. Recent preliminary results obtained with the 4 active channels in the prototype are also presented.

Positron range in tissue-equivalent materials: experimental microPET studies

Science.gov (United States)

Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

2016-09-01

In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

Monitoring and analysis PET/CT workplace radioactivity level in Shanghai

International Nuclear Information System (INIS)

Wang Bin; Gao Linfeng; Qian Aijun; Yao Jie; Shen Jinfu; Ji Guiyi

2012-01-01

Objective: To understand the PET/CT basic information in Shanghai, through monitoring radioactivity level of PET/CT workplace, to get the radiological protection information about PET/CT place. Methods: Through the γ radiation air absorbed dose rate and the β surface contamination to investigate PET/CT medical institutions in Shanghai. Results: By the end of 2011, there were 13 sets of PET/CT. Detecting show that γ radiation air absorbed dose rate is at relatively higher level in waiting room and the injection rooms, the date of waiting room door was up to 19552 nSv/h, the maximum value of injection room desk surface was 6136 nSv/h, the middle of injection room was up to 5408 nSv/h. Any date was certain the limits of national standard of β surface contamination, the middle of in the injection room. It is still higher on the window and wastes barrel. Conclusion: The radiation protection of PET/CT workplace is proper, surface contamination levels can be controlled within in the standard limits, but there are a blank of limits about nuclear medicine place of γ radiation absorbed dose rate air in the national standard, and external exposure protection is still the key of radiation protection. (authors)

PET in management of breast cancer

International Nuclear Information System (INIS)

Lee, Myung-Chul

2004-01-01

Full text: PET provides useful information about tumor metabolism enabling accurate visualization of malignant lesions. Approximately 60-80% suspicious lesions on mammography have benign histology and about 10% of breast cancers with palpable mass are not identified in mammography. The key roles of PET technology in breast cancer are in: primary diagnosis, staging, recurrent diseases monitoring and prediction of therapy response. The sensitivity and specificity of FDG-PET for the diagnosis of breast cancer has been reported to be 68-100% and 83-100%, respectively. Considering the increasing number of small breast tumors detected by mammography and false negative results, the clinical relevance of FDG-PET for the primary diagnosis is limited. In selected patients, however, for example with dense breasts, breasts implants, augmented breast or after breast surgery, which can affect the accuracy of mammography, and in cases with equivocal mammography, FDG-PET can provide clinically relevant information. PET accurately determines the extent of disease, including the loco-regional lymph node status. Furthermore, whole-body PET imaging promises a high diagnostic accuracy for detecting recurrent or metastatic breast carcinoma with a high positive predictive value. We studied the usefulness of the FDG-PET in 42 preoperative patients with suspected breast cancer in differentiation of lesions. The diagnostic value of FDG-PET in terms of sensitivity and specificity was 95% and 77% respectively in primary mass while it was 73% and 100% for axillary lymph nodes. PET is much more accurate than other conventional modalities. The sensitivity of FDG-PET for correct staging of axillary nodal status is 84-100%. It has the potential to replace conventional procedures for the staging of distant metastases. We observed the sensitivity and the specificity of FDG-PET to be 96% and 85% to detect distant metastases. FDG-PET may become the method of choice for the early assessment of

Staging of untreated nasopharyngeal carcinoma with PET/CT: comparison with conventional imaging work-up

International Nuclear Information System (INIS)

Ng, Shu-Hang; Chan, Sheng-Chieh; Yen, Tzu-Chen; Liu, Feng-Yuan; Chang, Joseph Tung-Chieh; Fan, Kang-Hsing; Liao, Chun-Ta; Ko, Sheung-Fat; Chin, Shu-Chyn; Hsu, Cheng-Lung

2009-01-01

We prospectively compared PET/CT and conventional imaging for initial staging of nasopharyngeal carcinoma (NPC). A total of 111 patients with histologically proven NPC were investigated with PET/CT and conventional imaging (head-and-neck MRI, chest X-ray, abdominal ultrasound, and bone scan) before treatment. The respective findings were reviewed independently and then compared with each other. With regard to T staging, PET/CT showed a discrepancy with head-and-neck MRI in 36 (32.4%) of the study subjects. With regard to N staging, PET/CT showed a discrepancy with head-and-neck MRI in 15 (13.5%) patients. Among the discordant cases, MRI was superior in demonstrating tumor involvement in the parapharyngeal space, skull base, intracranial area, sphenoid sinus, and retropharyngeal nodes while PET/CT was superior in demonstrating neck nodal metastasis. PET/CT disclosed 13 of 16 patients with distant malignancy compared with four patients disclosed by conventional imaging work-up. The false-positive rate of PET/CT was 18.8%. PET/CT correctly modified M staging in eight patients (7.2%) and disclosed a second primary lung malignancy in one patient (0.9%). In NPC patients, MRI appears to be superior to PET/CT for the assessment of locoregional invasion and retropharyngeal nodal metastasis. PET/CT is more accurate than MRI for determining cervical nodal metastasis and should be the better reference for the neck status. PET/CT has an acceptable diagnostic yield and a low false-positive rate for the detection of distant malignancy and can replace conventional work-up to this aim. PET/CT and head-and-neck MRI are suggested for the initial staging of NPC patients. (orig.)

Simplified quantification of small animal [{sup 18}F]FDG PET studies using a standard arterial input function

Energy Technology Data Exchange (ETDEWEB)

Meyer, Philipp T. [University Hospital Aachen, Department of Neurology, Aachen (Germany); Circiumaru, Valentina; Thomas, Daniel H. [University of Pennsylvania, Department of Radiology, Philadelphia (United States); Cardi, Christopher A.; Bal, Harshali; Acton, Paul D. [Thomas Jefferson University, Department of Radiology, Philadelphia (United States)

2006-08-15

Arterial input function (AIF) measurement for quantification of small animal PET studies is technically challenging and limited by the small blood volume of small laboratory animals. The present study investigated the use of a standard arterial input function (SAIF) to simplify the experimental procedure. Twelve [{sup 18}F]fluorodeoxyglucose ([{sup 18}F]FDG) PET studies accompanied by serial arterial blood sampling were acquired in seven male Sprague-Dawley rats under isoflurane anaesthesia without (every rat) and with additional (five rats) vibrissae stimulation. A leave-one-out procedure was employed to validate the use of a SAIF with individual scaling by one (1S) or two (2S) arterial blood samples. Automatic slow bolus infusion of [{sup 18}F]FDG resulted in highly similar AIF in all rats. The average differences of the area under the curve of the measured AIF and the individually scaled SAIF were 0.11{+-}4.26% and 0.04{+-}2.61% for the 1S (6-min sample) and the 2S (4-min/43-min samples) approach, respectively. The average differences between the cerebral metabolic rates of glucose (CMR{sub glc}) calculated using the measured AIF and the scaled SAIF were 1.31{+-}5.45% and 1.30{+-}3.84% for the 1S and the 2S approach, respectively. The use of a SAIF scaled by one or (preferably) two arterial blood samples can serve as a valid substitute for individual AIF measurements to quantify [{sup 18}F]FDG PET studies in rats. The SAIF approach minimises the loss of blood and should be ideally suited for longitudinal quantitative small animal [{sup 18}F]FDG PET studies. (orig.)

Validating PET segmentation of thoracic lesions-is 4D PET necessary?

DEFF Research Database (Denmark)

Nielsen, M. S.; Carl, J.

2017-01-01

Respiratory-induced motions are prone to degrade the positron emission tomography (PET) signal with the consequent loss of image information and unreliable segmentations. This phantom study aims to assess the discrepancies relative to stationary PET segmentations, of widely used semiautomatic PET...... segmentation methods on heterogeneous target lesions influenced by motion during image acquisition. Three target lesions included dual F-18 Fluoro-deoxy-glucose (FDG) tracer concentrations as high-and low tracer activities relative to the background. Four different tracer concentration arrangements were...... segmented using three SUV threshold methods (Max40%, SUV40% and 2.5SUV) and a gradient based method (GradientSeg). Segmentations in static 3D-PET scans (PETsta) specified the reference conditions for the individual segmentation methods, target lesions and tracer concentrations. The motion included PET...

Health Examination by PET. (1) Cancer Examination

International Nuclear Information System (INIS)

Uno, Koichi

2006-01-01

Cancer examination by positron emission tomography (PET) started in Japan in 1994 and has been rapidly popularized. This paper describes author's experience of the examination in his hospital along the recent Japanese guideline for the PET cancer examination. Fluorodeoxyglucose (FDG) is intravenously injected at 3.7 (or 4.6, for diabetic patients) MBq/kg after 4-5 hr fasting and 40 min later, imaging is conducted with additional delayed scan at 2 hr to reduce the possible false positive. Image is taken by the equipment with PET-specific camera, of which quality assurance (QA) is maintained according to the guideline, and 3D image is constructed by the ordered subset expectation maximization method. Number of examinees during 4.5 years are 18,210 (M/F=9,735/8,475), and 236 (1.3%), together with use of other test measures like ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), biochemical marker and occult blood as well, are found to have cancer of thyroid, large bowel, lung, breast and others. The false negative rate by PET alone is 78/236 (33%) for cancer. PET examination has problems of image reading and specificity of organs, and tasks of informed consent, test cost, increased exchange of information and radiation exposure. However, PET cancer examination will be established as a routine diagnostic tool when the accumulated evidence of early cancer detection is shown useful for improving the survival rate and for reducing the medicare cost. (T.I.)

Imaging results and TOF studies with axial PET detectors

Science.gov (United States)

Joram, Christian

2013-12-01

We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the field of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations (PET concept making use of the novel digital SiPM detectors by Philips. After reproducing comparable energy and spatial resolution on a small digital AX-PET set-up with 100 mm long crystals, we demonstrated a coincidence resolving time of about 210 ps FWHM.

The consumption and recycling collection system of PET bottles: a case study of Beijing, China.

Science.gov (United States)

Zhang, Hua; Wen, Zong-Guo

2014-06-01

After studying the recycling collection system of polyethylene terephthalate (PET) bottles worldwide, the authors conducted an intercept survey in Beijing. Two separate questionnaires were issued, one questionnaire to PET bottle consumers and one to PET bottle recyclers. In this study, consumers are defined as people that consume PET-bottled beverages in their daily life. Recyclers were defined as those involved in the collection and recycling of PET bottles. These include scavengers, itinerant waste buyers, small community waste-buying depots, medium/large redemption depots, and recycling companies. In total, 580 surveys were completed, including 461 by consumers and 119 by recyclers. The authors found that consumption of PET bottles in Beijing was nearly 100,000 tonnes in 2012. Age, occupation, gender, and education were identified as significant factors linked to PET-bottled beverage consumption, while income was not a significant factor. 90% Of post-consumed PET bottles were collected by informal collectors (i.e., scavengers and itinerant waste buyers). The survey also found that nearly all PET bottles were reprocessed by small factories that were not designed with pollution control equipment, which allows them to offer higher prices for waste recyclable bottles. As Beijing is trying to build a formal recycling collection system for recyclables, subsidies should be given to the formal recycling sector rather than being charged land use fees, and attention should also be given to informal recyclers that make their living from the collection of recyclables. Informal and formal sectors may work together by employing the scavengers and itinerant waste buyers for the formal sectors. In addition to the recycling of PET bottles, concern should also be allocated to reduce consumption, especially among young people, as they, compared to other groups, have a stronger demand for PET-bottled beverages and will be the main body of society. Copyright © 2013 Elsevier Ltd

Simultaneous PET-MR acquisition and MR-derived motion fields for correction of non-rigid motion in PET

International Nuclear Information System (INIS)

Tsoumpas, C.; Mackewn, J.E.; Halsted, P.; King, A.P.; Buerger, C.; Totman, J.J.; Schaeffter, T.; Marsden, P.K.

2010-01-01

Positron emission tomography (PET) provides an accurate measurement of radiotracer concentration in vivo, but performance can be limited by subject motion which degrades spatial resolution and quantitative accuracy. This effect may become a limiting factor for PET studies in the body as PET scanner technology improves. In this work, we propose a new approach to address this problem by employing motion information from images measured simultaneously using a magnetic resonance (MR) scanner. The approach is demonstrated using an MR-compatible PET scanner and PET-MR acquisition with a purpose-designed phantom capable of non-rigid deformations. Measured, simultaneously acquired MR data were used to correct for motion in PET, and results were compared with those obtained using motion information from PET images alone. Motion artefacts were significantly reduced and the PET image quality and quantification was significantly improved by the use of MR motion fields, whilst the use of PET-only motion information was less successful. Combined PET-MR acquisitions potentially allow PET motion compensation in whole-body acquisitions without prolonging PET acquisition time or increasing radiation dose. This, to the best of our knowledge, is the first study to demonstrate that simultaneously acquired MR data can be used to estimate and correct for the effects of non-rigid motion in PET. (author)

Uniformity studies inter cut with continuous movement PET stretcher; Homogeneidad intercorte de estudios PET con movimiento continuo de camila

Energy Technology Data Exchange (ETDEWEB)

Cons Perez, N.; Gomez Gonzalez, N.; Garcia Repiso, S.; Hernandez Rodriguez, J.; Montes Fuentes, C.; Garcia Ledesma, J.; Diez Gallego, M. A.

2015-07-01

One of the latest advances in PET scanners is the introduction of acquisitions with continuous movement of stretcher (CBM) Among the benefits that this technology brings they are: lower axial variation of noise, greater flexibility in planning studies with different levels of statistics for different anatomical and greater patient comfort regions. Behavior unexpected because the concentration obtained in all CBMs studies with PET-CT scanner Biograph mCTFlow (Slemens Medica Solutions) we propose a quantitative analysis with a series of parameters chosen to assess the inhomogeneity between cuts in the concentration obtained by homogeneous mannequins. A comparison with studies of static bed (S and S) indicates a problem only mode dynamic bed. (Author)

PET and PET/CT with radiolabeled choline in prostate cancer: a critical reappraisal of 20 years of clinical studies

Energy Technology Data Exchange (ETDEWEB)

Giovacchini, Giampiero; Giovannini, Elisabetta; Leoncini, Rossella; Riondato, Mattia; Ciarmiello, Andrea [S. Andrea Hospital, Nuclear Medicine Department, La Spezia (Italy)

2017-09-15

We here aim to provide a comprehensive and critical review of the literature concerning the clinical applications of positron emission tomography/computed tomography (PET/CT) with radiolabeled choline in patients with prostate cancer (PCa). We will initially briefly summarize the historical context that brought to the synthesis of [{sup 11}C]choline, which occurred exactly 20 years ago. We have arbitrarily grouped the clinical studies in three different periods, according to the year in which they were published and according to their relation with their applications in urology, radiotherapy and oncology. Studies at initial staging and, more extensively, studies in patients with biochemical failure, as well as factors predicting positive PET/CT will be reviewed. The capability of PET/CT with radiolabeled choline to provide prognostic information on PCa-specific survival will also be examined. The last sections will be devoted to the use of radiolabeled choline for monitoring the response to androgen deprivation therapy, radiotherapy, and chemotherapy. The accuracy and the limits of the technique will be discussed according to the information available from standard validation processes, including biopsy or histology. The clinical impact of the technique will be discussed on the basis of changes induced in the management of patients and in the evaluation of the response to therapy. Current indications to PET/CT, as officially endorsed by guidelines, or as routinely performed in the clinical practice will be illustrated. Emphasis will be made on methodological factors that might have influenced the results of the studies or their interpretation. Finally, we will briefly highlight the potential role of positron emission tomography/magnetic resonance and of new radiotracers for PCa imaging. (orig.)

Bone formation rather than inflammation reflects Ankylosing Spondylitis activity on PET-CT: a pilot study

OpenAIRE

Bruijnen, Stefan TG; van der Weijden, Mignon AC; Klein, Joannes P; Hoekstra, Otto S; Boellaard, Ronald; van Denderen, J Christiaan; Dijkmans, Ben AC; Voskuyl, Alexandre E; van der Horst-Bruinsma, Irene E; van der Laken, Conny J

2012-01-01

Introduction Positron Emission Tomography - Computer Tomography (PET-CT) is an interesting imaging technique to visualize Ankylosing Spondylitis (AS) activity using specific PET tracers. Previous studies have shown that the PET tracers [18F]FDG and [11C](R)PK11195 can target inflammation (synovitis) in rheumatoid arthritis (RA) and may therefore be useful in AS. Another interesting tracer for AS is [18F]Fluoride, which targets bone formation. In a pilot setting, the potential of PET-CT in ima...

Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants

International Nuclear Information System (INIS)

Goerres, Gerhard W.; Hany, Thomas F.; Kamel, Ehab; Schulthess von, Gustav K.; Buck, Alfred

2002-01-01

Germanium-68 based attenuation correction (PET Ge68 ) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PET CT ) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PET Ge68 and PET CT . Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET CT in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET Ge68 images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PET Ge68 and PET CT images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional 68 Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be

Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET

DEFF Research Database (Denmark)

Christensen, Anders Nymark; Reichkendler, Michala H.; Larsen, Rasmus

2014-01-01

We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low...

18F-FDG PET of the hands with a dedicated high-resolution PEM system (arthro-PET): correlation with PET/CT, radiography and clinical parameters.

Science.gov (United States)

Mhlanga, Joyce C; Carrino, John A; Lodge, Martin; Wang, Hao; Wahl, Richard L

2014-12-01

The aim of this study was to prospectively determine the feasibility and compare the novel use of a positron emission mammography (PEM) scanner with standard PET/CT for evaluating hand osteoarthritis (OA) with (18)F-FDG. Institutional review board approval and written informed consent were obtained for this HIPAA-compliant prospective study in which 14 adults referred for oncological (18)F-FDG PET/CT underwent dedicated hand PET/CT followed by arthro-PET using the PEM device. Hand radiographs were obtained and scored for the presence and severity of OA. Summed qualitative and quantitative joint glycolytic scores for each modality were compared with the findings on plain radiography and clinical features. Eight patients with clinical and/or radiographic evidence of OA comprised the OA group (mean age 73 ± 7.7 years). Six patients served as the control group (53.7 ± 9.3 years). Arthro-PET quantitative and qualitative joint glycolytic scores were highly correlated with PET/CT findings in the OA patients (r = 0.86. p = 0.007; r = 0.94, p = 0.001). Qualitative arthro-PET and PET/CT joint scores were significantly higher in the OA patients than in controls (38.7 ± 6.6 vs. 32.2 ± 0.4, p = 0.02; 37.5 ± 5.4 vs. 32.2 ± 0.4, p = 0.03, respectively). Quantitative arthro-PET and PET/CT maximum SUV-lean joint scores were higher in the OA patients, although they did not reach statistical significance (20.8 ± 4.2 vs. 18 ± 1.8, p = 0.13; 22.8 ± 5.38 vs. 20.1 ± 1.54, p = 0.21). By definition, OA patients had higher radiographic joint scores than controls (30.9 ± 31.3 vs. 0, p = 0.03). Hand imaging using a small field of view PEM system (arthro-PET) with FDG is feasible, performing comparably to PET/CT in assessing metabolic joint activity. Arthro-PET and PET/CT showed higher joint FDG uptake in OA. Further exploration of arthro-PET in arthritis management is warranted.

Clinical studies on the use of PET in radiotherapy planning in Germany. An update; Klinische Studien zum Einsatz der PET in der Bestrahlungsplanung in Deutschland. Ein Update

Energy Technology Data Exchange (ETDEWEB)

Nestle, U.; Mix, M.; Weber, W.; Grosu, A.L. [Universitaetsklinikum Freiburg (Germany). Kliniken fuer Strahlenheilkunde und Nuklearmedizin

2011-07-15

In recent years, PET and PET/CT have well been established for staging and restaging of various malignancies. Increasingly, the modality is also used for radiotherapy treatment planning. However, clinical studies investigating the patients benefit by the inclusion of those modalities into RT treatment planning are mandatory, simultaneously defining standards for future care. Chances and problems of such studies are discussed using the examples of the PET-Plan and GLIAA trials. (orig.)

Influence of PSA, PSA velocity and PSA doubling time on contrast-enhanced {sup 18}F-choline PET/CT detection rate in patients with rising PSA after radical prostatectomy

Energy Technology Data Exchange (ETDEWEB)

Schillaci, Orazio [University ' ' Tor Vergata' ' , Department of Biopathology and Diagnostic Imaging, Interventional, Rome (Italy); IRCCS Neuromed, Department of Nuclear Medicine and Molecular Imaging, Pozzilli (Italy); Calabria, Ferdinando [IRCCS Neuromed, Department of Nuclear Medicine and Molecular Imaging, Pozzilli (Italy); Tavolozza, Mario; Caracciolo, Cristiana Ragano; Orlacchio, Antonio; Danieli, Roberta; Simonetti, Giovanni [University ' ' Tor Vergata' ' , Department of Biopathology and Diagnostic Imaging, Interventional, Rome (Italy); Agro, Enrico Finazzi; Miano, Roberto [University Hospital ' ' Tor Vergata' ' , Department of Urology, Rome (Italy)

2012-04-15

To evaluate the accuracy of contrast-enhanced {sup 18}F-choline PET/CT in restaging patients with prostate cancer after radical prostatectomy in relation to PSA, PSA velocity (PSAve) and PSA doubling time (PSAdt). PET/CT was performed in 49 patients (age range 58-87 years) with rising PSA (mean 4.13 ng/ml) who were divided in four groups according to PSA level: {<=}1 ng/ml, 1 to {<=}2 ng/ml, 2 to {<=}4 ng/ml, and >4 ng/ml. PSAve and PSAdt were measured. PET and CT scans were interpreted separately and then together. PET/CT diagnosed relapse in 33 of the 49 patients (67%). The detection rates were 20%, 55%, 80% and 87% in the PSA groups {<=}1, 1 to {<=}2, 2 to {<=}4 and >4 ng/ml, respectively. PET/CT was positive in 7 of 18 patients (38.9%) with a PSA {<=}2 ng/ml, and in 26 of 31 (83.9%) with a PSA >2 ng/ml. PET/CT was positive in 7 of 25 patients (84%) with PSAdt {<=}6 months, and in 12 of 24 patients (50%) with PSAdt >6 months, and was positive in 26 of 30 patients (86%) with a PSAve >2 ng/ml per year, and in 7 of 19 patients (36.8%) with PSAve {<=}2 ng/ml per year. PET alone was positive in 31 of 49 patients (63.3%), and of these 31 patients, CT was negative in 14 but diagnosed bone lesions in 2 patients in whom PET alone was negative. CT with the administration of intravenous contrast medium did not provide any further information. Detection rate of {sup 18}F-choline imaging is closely related to PSA and PSA kinetics. In particular, {sup 18}F-choline PET/CT is recommended in patients with PSA >2 ng/ml, PSAdt {<=}6 months and PSAve >2 ng/ml per year. CT is useful for detecting bone metastases that are not {sup 18}F-choline-avid. The use of intravenous contrast agent seems unnecessary. (orig.)

Synergistic Effect of PET/CT and HRCT in Diagnosing Solitary Bronchioloalveolar Carcinoma%PET/CT与HRCT在孤立型细支气管肺泡癌诊断中的协同应用价值

Institute of Scientific and Technical Information of China (English)

彭辽河; 丁久荣; 李杰; 邱大胜; 胡晓燕; 朱佳; 周静

2012-01-01

目的 探讨正电子发射计算机体层成像(PET/CT)与高分辨率CT(HRCT)在孤立型细支气管肺泡癌(solitary bronchioloalveolar carcinoma,SBAC)诊断中协同应用的价值,以提高对该病的诊断准确率.方法 搜集经手术病理证实的28例SBAC患者的PET/CT及HRCT影像资料,患者均先行PET/CT显像,其中16例根据诊断需要于0～3天内行HRCT检查,分析两者对SBAC的协同诊断价值.结果 28例中,PET/CT显像确切诊断肺癌者15例(53.6％),恶性不除外5例(17.9％),良性病变8例(28.6％),误诊率较高.16例HRCT协同PET/CT确切诊断肺癌15例,其中1例初诊良性病变,后经HRCT结合图像后处理技术诊断为肺癌,1例伴右肺门淋巴结转移者,HRCT图像仅显示形态正常淋巴结影,而PET/CT诊断淋巴结转移,后经病理证实；PET/CT与HRCT协同诊断正确率达100％.结论 PET/CT显像诊断SBAC易出现假阴性,误诊率较高；PET/CT与HRCT在SBAC诊断中的协同应用能够弥补常规PET/CT显像中的不足,达到优势互补并充分发挥PET/CT的资源优势,有助于提高对SBAC的诊断准确率.%Objective To evaluate the synergistic effect of PET/CT and HRCT in diagnosing solitary bronchioloalveolar carcinoma (SB AC). Methods The PET/CT images of 28 cases with pathologically confirmed SB AC were studied. Sixteen of the 28 cases were followed up after 0-3 days by HRCT study. The diagnostic accuracy rate and synergistic effect of PET/CT and HRCT were analyzed. Results According to PET/CT, there was definite diagnosis of malignant in 15 cases (53.6% ) , no exclusion of malignancies in 5 cases (17. 9% ) , definite diagnosis of benign tumors in 8 cases( 28. 6% ). The misdiagnosis rate of PET/CT was high. According to PET/CT combined with HRCT, there was diagnosis of malignant tumors in 15 cases. One tumor diagnosed firstly as benign tumor by PET/CT, were definitely diagnosed as malignant by HRCT and three-dimensional images. In addition,one case of right hilar

On the fractal nature of dynamic positron emission tomography (PET) studies

International Nuclear Information System (INIS)

Dimitrakopoulou-Strauss, A.; Strauss, L.G.; Mikolajczyk, K.; Burger, C.; Lehnert, T.; Bernd, L.; Ewerbeck, V.

2003-01-01

Quantification of dynamic PET Studies is generally based on compartmental methods. This is a report about the implementation and assessment of a new non-compartmental method, the fractal dimension (FD), a parameter based on the box counting (BC) procedure of the chaos theory for the analysis of dynamic PET data. The evaluation included 200 malignant lesions in 159 patients with different tumour entities as well as 57 benign lesions for comparison. 101/200 malignant lesions were treated with chemotherapy, whereas 99/200 malignant lesions as well as all 57 benign lesions were untreated within the last six months prior to the PET study with F-18-Fluorodeoxyglucose (FDG). The evaluation of the FDG kinetics was performed using the BC based FD for the time-activity data. Visual assessment demonstrated generally different FDG uptake patterns in the conventional images and the parametric images of FD. FD estimates depended on the number of boxes and the maximum cut-off value used for calculation. Based on the discriminant analysis for benign and malignant lesions, FD demonstrated an accuracy of 76.65% for all patients, 67.7% for the untreated patients and 83.44% for the treated group. The use of the BC based FD is a reliable, new method for the quantification of dynamic PET studies and seems to be in particular helpful for the evaluation of treated malignant lesions. (author)

18F-FDG PET-CT显像在头颈部肿瘤的临床诊断中的效果研究%Study on the effect of 18F-FDG PET-CT in diagnosis of head and neck cancer

Institute of Scientific and Technical Information of China (English)

王家富; 李勇; 韩巍; 王丽范; 马铎

2012-01-01

OBJECTIVE To evaluate of the efficacy of 18F-FDG PET-CT in diagnosis of head and neck cancer. METHODS Patients diagnozed by 18F-FDG PET-CT imaging were collected for analysis. RESULTS The total detection rate of PET/CT was significantly higher than that of PET and CT. The positioning accuracy of PET/CT was significantly higher than that of PET. CONCLUSION T-FDG PET-CT can effectively identify the head and neck cancer treatment scar and tumor recurrence, lymph node and distant organ metastasis, and improve the sensitivity and accuracy of diagnosis.%目的 评价18F-FDG PET-CT对头颈部肿瘤患者的临床诊断价值.方法 患者均行18F-FDG PET-CT显像,对图像进行分析.结果 PET/CT的总检出率高于PET和CT,PET/CT的定位准确率高于PET.结论 18F-FDG PET-CT能够有效地鉴别头颈部肿瘤治疗后瘢痕与肿瘤复发、淋巴结及远处脏器转移,可提高对其诊断的敏感性和准确性.

Prognostic value of 18F-FLT PET in patients with neuroendocrine neoplasms

DEFF Research Database (Denmark)

Johnbeck, Camilla B.; Knigge, Ulrich; Langer, Seppo W.

2016-01-01

Neuroendocrine neoplasms (NENs) constitute a heterogeneous group of tumors arising in various organs and with a large span of aggressiveness and survival rates. The Ki-67 proliferation index is presently used as the key marker of prognosis, and treatment guidelines are largely based on this index...... study was to investigate 18F-FLT PET as a prognostic marker for NENs in comparison with 18F-FDG PET and Ki-67 index. Methods: One hundred patients were PET-scanned with both 18F-FLT and 18F-FDG within the same week, and the prognostic value of a positive scan was examined in terms of progression...... prognostic value in NEN patients but when 18F-FDG PET and Ki-67 index are also available, a multivariate model revealed that 18F-FLT PET only adds information regarding PFS but not OS, whereas 18F-FDG PET remains predictive of both PFS and OS. However, a clinically robust algorithm including 18F...

Development of PET in Latin America. Experience of the first PET-Cyclotron Center

International Nuclear Information System (INIS)

Tutor, C.A.; Frias, L.

2002-01-01

Aim: Describe the experience of the first PET-Cyclotron Center in Latin America. Demonstrate the viability of running a PET Center in Argentina despite the economic crisis. Materials and Methods: For this study, we used a UGM/GE Quest 250 PET scan, a RDS 112 cyclotron and a Radiosynthesis Laboratory installed at the (FUESMEN) Nuclear Medicine School Foundation, located in Mendoza City, in the middle-west of Argentina. From January 1999 to March 2002, 741 studies were obtained, 731 were 18 FluorDeoxyGlucose-PET studies and 10 phantoms for calibration purposes. We used acquisition and imaging processing standard protocols, as well as research protocols designed according to the pathology under investigation. To better correlate anatomical and functional images, we used fusion techniques with (CT) Computed Tomography in some (WB) whole-body PET scans. Results: A total of 731 patients were retrospectively analyzed and classified according to statistics variables such as: 1-sex: 317 women and 414 men, 2-type of scan: 439 WB cases, 267 brain studies and 25 cardiac. From this data we divided them as PET indications and resulted in 17 cases as healthy volunteers, 422 oncological cases, 267 neurological studies and 25 cardiac for myocardial viability. According to the origin they were classified as patients coming from Mendoza 544, Buenos Aires 112, other argentine provinces 60 and foreign (Chile, Brazil and Uruguay) 15 cases. In terms of billing, 181 studies were done free of charge, 95 under research protocols were also done free of charge and 451 were charged. Conclusion: Not only the economical and political factors play an important role limiting the advances of PET Imaging in Latin America, but also the lack of a neighboring cyclotron that circumscribe many hospitals to have access to the radiopharmaceutical agent. FUESMEN was established in 1991 by three governmental entities: the (CONEA) National Commission of Atomic Energy, the (UNC) National University of Cuyo and

CYBPET: a cylindrical PET system for breast imaging

Energy Technology Data Exchange (ETDEWEB)

Karimian, A. [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of) and Nuclear Research Center for Agriculture and Medicine (NRCAM-AEOI), P.O. BOX. (31485-498), Karaj, Iran, Islamic Republic of and Department of Experimental Medicine and Pathology, University of Rome, La Sapienza, Rome (Italy)]. E-mail: akarimian@nrcam.org; Thompson, C.J. [Montreal Neurological Institute, McGill University, Montreal QC (Canada); Sarkar, S. [Medical physics Department of Tehran University of Medical Sciences and (RCSTIM), Tehran (Iran, Islamic Republic of); Raisali, G. [Nuclear Research Center for Agriculture and Medicine (NRCAM-AEOI), P.O. BOX. (31485-498), Karaj (Iran, Islamic Republic of); Pani, R. [Department of Experimental Medicine and Pathology, University of Rome La Sapienza, Rome (Italy); Davilu, H. [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Sardari, D. [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2005-06-11

We propose a Cylindrical Breast PET (CYBPET) system for breast imaging with patients in the prone position. An individual pendulous breast is covered by thin plastic to provide reduced pressure fixation and surrounded by the crystals inside the CYBPET ring. Each breast is imaged separately. The rest of the body is shielded properly to minimize the contribution of scattered photons from the other breast and the rest of the body. To compare the CYBPET with whole-body PET (WB-PET) the simulations of CYBPET and a WB-PET (GE-Advance) for a 10 mm tumor inside the breast with a lesion to background (breast) activity concentration of 6 to 1 were made. The noise effective count rate (NECR) of CYBPET is about twice that of WB-PET at activity concentrations less than 3.1 {mu}Ci/cc. The spatial resolution of CYBPET is better by 25% than the WB-PET.

CYBPET: a cylindrical PET system for breast imaging

International Nuclear Information System (INIS)

Karimian, A.; Thompson, C.J.; Sarkar, S.; Raisali, G.; Pani, R.; Davilu, H.; Sardari, D.

2005-01-01

We propose a Cylindrical Breast PET (CYBPET) system for breast imaging with patients in the prone position. An individual pendulous breast is covered by thin plastic to provide reduced pressure fixation and surrounded by the crystals inside the CYBPET ring. Each breast is imaged separately. The rest of the body is shielded properly to minimize the contribution of scattered photons from the other breast and the rest of the body. To compare the CYBPET with whole-body PET (WB-PET) the simulations of CYBPET and a WB-PET (GE-Advance) for a 10 mm tumor inside the breast with a lesion to background (breast) activity concentration of 6 to 1 were made. The noise effective count rate (NECR) of CYBPET is about twice that of WB-PET at activity concentrations less than 3.1 μCi/cc. The spatial resolution of CYBPET is better by 25% than the WB-PET

The value of [11C]-acetate PET and [18F]-FDG PET in hepatocellular carcinoma before and after treatment with transarterial chemoembolization and bevacizumab

International Nuclear Information System (INIS)

Li, Shuren; Ubl, Philipp; Wadsak, Wolfgang; Mitterhauser, Markus; Rainer, Eva; Haug, Alexander; Hacker, Marcus; Peck-Radosavljevic, Markus; Pinter, Matthias; Wang, Hao; Nanoff, Christian; Kaczirek, Klaus

2017-01-01

This prospective study was to investigate the value of [ 11 C]-acetate PET and [ 18 F]-FDG PET in the evaluation of hepatocellular carcinoma (HCC) before and after treatment with transarterial chemoembolization (TACE) and vascular endothelial growth factor (VEGF) antibody (bevacizumab). Twenty-two patients (three women, 19 men; 62 ± 8 years) with HCC verified by histopathology were treated with TACE and bevacizumab (n = 11) or placebo (n = 11). [ 11 C]-acetate PET and [ 18 F]-FDG PET were performed before and after TACE with bevacizumab or placebo. Comparisons between groups were performed with t-tests and Chi-squared tests, where appropriate. Overall survival (OS) was defined as the time from start of bevacizumab or placebo until the date of death/last follow-up, respectively. The patient-related sensitivity of [ 11 C]-acetate PET, [ 18 F]-FDG PET, and combined [ 11 C]-acetate and [ 18 F]-FDG PET was 68%, 45%, and 73%, respectively. There was a significantly higher rate of conversion from [ 11 C]-acetate positive lesions to negative lesions in patients treated with TACE and bevacizumab as compared with that in patients with TACE and placebo (p < 0.05). In patients with negative acetate PET, the mean OS in patients treated with TACE and bevacizumab was 259 ± 118 days and was markedly shorter as compared with that (668 ± 217 days) in patients treated with TACE and placebo (p < 0.05). In patients treated with TACE and placebo, there was significant difference in mean OS in patients with positive FDG PET as compared with that in patients with negative FDG PET (p < 0.05). The HCC lesions had different tracer avidities showing the heterogeneity of HCC. Our study suggests that combining [ 18 F]-FDG with [ 11 C]-acetate PET could be useful for the management of HCC patients and might also provide relevant prognostic and molecular heterogeneity information. (orig.)

The value of [11C]-acetate PET and [18F]-FDG PET in hepatocellular carcinoma before and after treatment with transarterial chemoembolization and bevacizumab.

Science.gov (United States)

Li, Shuren; Peck-Radosavljevic, Markus; Ubl, Philipp; Wadsak, Wolfgang; Mitterhauser, Markus; Rainer, Eva; Pinter, Matthias; Wang, Hao; Nanoff, Christian; Kaczirek, Klaus; Haug, Alexander; Hacker, Marcus

2017-09-01

This prospective study was to investigate the value of [ 11 C]-acetate PET and [ 18 F]-FDG PET in the evaluation of hepatocellular carcinoma (HCC) before and after treatment with transarterial chemoembolization (TACE) and vascular endothelial growth factor (VEGF) antibody (bevacizumab). Twenty-two patients (three women, 19 men; 62 ± 8 years) with HCC verified by histopathology were treated with TACE and bevacizumab (n = 11) or placebo (n = 11). [ 11 C]-acetate PET and [ 18 F]-FDG PET were performed before and after TACE with bevacizumab or placebo. Comparisons between groups were performed with t-tests and Chi-squared tests, where appropriate. Overall survival (OS) was defined as the time from start of bevacizumab or placebo until the date of death/last follow-up, respectively. The patient-related sensitivity of [ 11 C]-acetate PET, [ 18 F]-FDG PET, and combined [ 11 C]-acetate and [ 18 F]-FDG PET was 68%, 45%, and 73%, respectively. There was a significantly higher rate of conversion from [ 11 C]-acetate positive lesions to negative lesions in patients treated with TACE and bevacizumab as compared with that in patients with TACE and placebo (p < 0.05). In patients with negative acetate PET, the mean OS in patients treated with TACE and bevacizumab was 259 ± 118 days and was markedly shorter as compared with that (668 ± 217 days) in patients treated with TACE and placebo (p < 0.05). In patients treated with TACE and placebo, there was significant difference in mean OS in patients with positive FDG PET as compared with that in patients with negative FDG PET (p < 0.05). The HCC lesions had different tracer avidities showing the heterogeneity of HCC. Our study suggests that combining [ 18 F]-FDG with [ 11 C]-acetate PET could be useful for the management of HCC patients and might also provide relevant prognostic and molecular heterogeneity information.

NIRS report of investigations for the development of the next generation PET apparatus. FY 2002

International Nuclear Information System (INIS)

2003-03-01

The present status of studies conducted by representative technology fields for the development of the next generation PET apparatus, and the summary of opinions given by investigators of nuclear medicine are reported. The former involves chapters of: Summary of representative technologies for the development of the next generation PET apparatus; Count rate analysis of PET apparatuses for the whole body and small animals by PET simulator; Scintillator; DOI (depth of interaction) detector-evaluation of the detector with 256-ch fluorescence polarization-photomultiplier tubes (FP-PMT) trial apparatus etc; Examination of multi-slice DOI-MR compatible detector for PET; Development of application specific integrated circuit (ASIC) for processing the front-end signals; Detector simulation; Circuit for processing PET detector signals; Signal processing-coincidence circuit; Data collection system; Signal processing technology for the next generation PET; Reconstruction of statistical PET image using DOI signals; Monte Carlo simulation and Unique directions-PET for infants and for the whole body autonomic nervous systems and mental activity; and Actual design and evaluation of image reconstruction by statistical means. Opinions are: Progress of clinical PET apparatus; Desirable PET drugs and apparatuses; From clinical practice for the development of the next generation PET apparatus; From clinical psychiatric studies for the development; From application of drug development and basic researches; From brain PET practice; From clinical PET practice; and The role of National Institute of Radiological Sciences (NIRS) in PET development. Also involved is the publication list. (N.I.)

{sup 11}C-MET PET/MRI for detection of recurrent glioma

Energy Technology Data Exchange (ETDEWEB)

Deuschl, C. [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Kirchner, J.; Schaarschmidt, B. [University Duesseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Poeppel, T.D.; Herrmann, K. [University Hospital Essen, Clinic for Nuclear Medicine, Essen (Germany); Kebir, S.; Glas, M. [University Hospital Essen, Division of Clinical Neurooncology, Department of Neurology, Essen (Germany); El Hindy, N. [University Hospital Essen, Department of Neurosurgery, Essen (Germany); Hense, J. [University Hospital Essen, Department of Medical Oncology, West German Cancer Center, Essen (Germany); Quick, H.H. [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany); Umutlu, L.; Moenninghoff, C.; Radbruch, A.; Forsting, M. [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Schlamann, M. [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); University Hospital Cologne, Department of Diagnostic and Interventional Radiology, Cologne (Germany)

2018-04-15

Radiological assessment of brain tumors is widely based on the Radiology Assessment of Neuro-Oncology (RANO) criteria that consider non-specific T1 and T2 weighted images. Limitation of the RANO criteria is that they do not include metabolic imaging techniques that have been reported to be helpful to differentiate treatment related changes from true tumor progression. In the current study, we assessed if the combined use of MRI and PET with hybrid {sup 11}C-MET PET/MRI can improve diagnostic accuracy and diagnostic confidence of the readers to differentiate treatment related changes from true progression in recurrent glioma. Fifty consecutive patients with histopathologically proven glioma were prospectively enrolled for a hybrid {sup 11}C-MET PET/MRI to differentiate recurrent glioma from treatment induced changes. Sole MRI data were analyzed based on RANO. Sole PET data and in a third evaluation hybrid {sup 11}C-MET-PET/MRI data were assessed for metabolic respectively metabolic and morphologic glioma recurrence. Diagnostic performance and diagnostic confidence of the reader were calculated for the different modalities, and the McNemar test and Mann-Whitney U Test were applied for statistical analysis. Hybrid {sup 11}C-MET PET/MRI was successfully performed in all 50 patients. Glioma recurrence was diagnosed in 35 of the 50 patients (70%). Sensitivity and specificity were calculated for MRI (86.11% and 71.43%), for {sup 11}C-MET PET (96.77% and 73.68%), and for hybrid {sup 11}C-MET-PET/MRI (97.14% and 93.33%). For diagnostic accuracy hybrid {sup 11}C-MET-PET/MRI (96%) showed significantly higher values than MRI alone (82%), whereas no significant difference was found for 11C-MET PET (88%). Furthermore, by rating on a five-point Likert scale significantly higher scores were found for diagnostic confidence when comparing {sup 11}C-MET PET/MRI (4.26 ± 0,777) to either PET alone (3.44 ± 0.705) or MRI alone (3.56 ± 0.733). This feasibility study showed that hybrid

Twelve automated thresholding methods for segmentation of PET images: a phantom study

International Nuclear Information System (INIS)

Prieto, Elena; Peñuelas, Iván; Martí-Climent, Josep M; Lecumberri, Pablo; Gómez, Marisol; Pagola, Miguel; Bilbao, Izaskun; Ecay, Margarita

2012-01-01

Tumor volume delineation over positron emission tomography (PET) images is of great interest for proper diagnosis and therapy planning. However, standard segmentation techniques (manual or semi-automated) are operator dependent and time consuming while fully automated procedures are cumbersome or require complex mathematical development. The aim of this study was to segment PET images in a fully automated way by implementing a set of 12 automated thresholding algorithms, classical in the fields of optical character recognition, tissue engineering or non-destructive testing images in high-tech structures. Automated thresholding algorithms select a specific threshold for each image without any a priori spatial information of the segmented object or any special calibration of the tomograph, as opposed to usual thresholding methods for PET. Spherical 18 F-filled objects of different volumes were acquired on clinical PET/CT and on a small animal PET scanner, with three different signal-to-background ratios. Images were segmented with 12 automatic thresholding algorithms and results were compared with the standard segmentation reference, a threshold at 42% of the maximum uptake. Ridler and Ramesh thresholding algorithms based on clustering and histogram-shape information, respectively, provided better results that the classical 42%-based threshold (p < 0.05). We have herein demonstrated that fully automated thresholding algorithms can provide better results than classical PET segmentation tools. (paper)

PET

DEFF Research Database (Denmark)

Mariager, Rasmus Mølgaard; Schmidt, Regin; Heiberg, Morten Rievers

PET handler om den hemmelige tjenestes arbejde under den kolde krig 1945-1989. Her fortæller Regin Schmidt, Rasmus Mariager og Morten Heiberg om de mest dramatiske og interessante sager fra PET's arkiv. PET er på flere måder en udemokratisk institution, der er sat til at vogte over demokratiet....... Dens virksomhed er skjult for offentligheden, den overvåger borgernes aktiviteter, og den registrerer følsomme personoplysninger. Historien om PET rejser spørgsmålet om, hvad man skal gøre, når befolkningen i et demokrati er kritisk indstillet over for overvågningen af lovlige politiske aktiviteter......, mens myndighederne mener, at det er nødvendigt for at beskytte demokratiet. PET er på en gang en fortælling om konkrete aktioner og begivenheder i PET's arbejde og et stykke Danmarkshistorie. Det handler om overvågning, spioner, politisk ekstremisme og international terrorisme.  ...

Automatic extraction of myocardial mass and volumes using parametric images from dynamic nongated PET

DEFF Research Database (Denmark)

Harms, Hendrik Johannes; Hansson, Nils Henrik Stubkjær; Tolbod, Lars Poulsen

2016-01-01

Dynamic cardiac positron emission tomography (PET) is used to quantify molecular processes in vivo. However, measurements of left-ventricular (LV) mass and volumes require electrocardiogram (ECG)-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using non......-gated dynamic cardiac PET. METHODS: Thirty-five patients with aortic-valve stenosis and 10 healthy controls (HC) underwent a 27-min 11C-acetate PET/CT scan and cardiac magnetic resonance imaging (CMR). HC were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were......LV and WT only and an overestimation for LVEF at lower values. Intra- and inter-observer correlations were >0.95 for all PET measurements. PET repeatability accuracy in HC was comparable to CMR. CONCLUSION: LV mass and volumes are accurately and automatically generated from dynamic 11C-acetate PET without...

Mixed reality virtual pets to reduce childhood obesity.

Science.gov (United States)

Johnsen, Kyle; Ahn, Sun Joo; Moore, James; Brown, Scott; Robertson, Thomas P; Marable, Amanda; Basu, Aryabrata

2014-04-01

Novel approaches are needed to reduce the high rates of childhood obesity in the developed world. While multifactorial in cause, a major factor is an increasingly sedentary lifestyle of children. Our research shows that a mixed reality system that is of interest to children can be a powerful motivator of healthy activity. We designed and constructed a mixed reality system that allowed children to exercise, play with, and train a virtual pet using their own physical activity as input. The health, happiness, and intelligence of each virtual pet grew as its associated child owner exercised more, reached goals, and interacted with their pet. We report results of a research study involving 61 children from a local summer camp that shows a large increase in recorded and observed activity, alongside observational evidence that the virtual pet was responsible for that change. These results, and the ease at which the system integrated into the camp environment, demonstrate the practical potential to impact the exercise behaviors of children with mixed reality.

Prospective head-to-head comparison of 11C-choline-PET/MR and 11C-choline-PET/CT for restaging of biochemical recurrent prostate cancer

International Nuclear Information System (INIS)

Eiber, Matthias; Rauscher, Isabel; Souvatzoglou, Michael; Schwaiger, Markus; Maurer, Tobias; Holzapfel, Konstantin; Beer, Ambros J.

2017-01-01

Whole-body integrated 11 C-choline PET/MR might provide advantages compared to 11 C-choline PET/CT for restaging of prostate cancer (PC) due to the high soft-tissue contrast and the use of multiparametric MRI, especially for detection of local recurrence and bone metastases. Ninety-four patients with recurrent PC underwent a single-injection/dual-imaging protocol with contrast-enhanced PET/CT followed by fully diagnostic PET/MR. Imaging datasets were read separately by two reader teams (team 1 and 2) assessing the presence of local recurrence, lymph node and bone metastases in predefined regions using a five-point scale. Detection rates were calculated. The diagnostic performance of PET/CT vs. PET/MR was compared using ROC analysis. Inter-observer and inter-modality variability, radiation exposure, and mean imaging time were evaluated. Clinical follow-up, imaging, and/or histopathology served as standard of reference (SOR). Seventy-five patients qualified for the final image analysis. A total of 188 regions were regarded as positive: local recurrence in 37 patients, 87 regions with lymph node metastases, and 64 regions with bone metastases. Mean detection rate between both readers teams for PET/MR was 84.7% compared to 77.3% for PET/CT (p > 0.05). Local recurrence was identified significantly more often in PET/MR compared to PET/CT by team 1. Lymph node and bone metastases were identified significantly more often in PET/CT compared to PET/MR by both teams. However, this difference was not present in the subgroup of patients with PSA values ≤2 ng/ml. Inter-modality and inter-observer agreement (K > 0.6) was moderate to substantial for nearly all categories. Mean reduction of radiation exposure for PET/MR compared to PET/CT was 79.7% (range, 72.6-86.2%). Mean imaging time for PET/CT was substantially lower (18.4 ± 0.7 min) compared to PET/MR (50.4 ± 7.9 min). 11 C-choline PET/MR is a robust imaging modality for restaging biochemical recurrent PC and

Simultaneous acquisition of multislice PET and MR images: initial results with a MR-compatible PET scanner.

Science.gov (United States)

Catana, Ciprian; Wu, Yibao; Judenhofer, Martin S; Qi, Jinyi; Pichler, Bernd J; Cherry, Simon R

2006-12-01

PET and MRI are powerful imaging techniques that are largely complementary in the information they provide. We have designed and built a MR-compatible PET scanner based on avalanche photodiode technology that allows simultaneous acquisition of PET and MR images in small animals. The PET scanner insert uses magnetic field-insensitive, position-sensitive avalanche photodiode (PSAPD) detectors coupled, via short lengths of optical fibers, to arrays of lutetium oxyorthosilicate (LSO) scintillator crystals. The optical fibers are used to minimize electromagnetic interference between the radiofrequency and gradient coils and the PET detector system. The PET detector module components and the complete PET insert assembly are described. PET data were acquired with and without MR sequences running, and detector flood histograms were compared with the ones generated from the data acquired outside the magnet. A uniform MR phantom was also imaged to assess the effect of the PET detector on the MR data acquisition. Simultaneous PET and MRI studies of a mouse were performed ex vivo. PSAPDs can be successfully used to read out large numbers of scintillator crystals coupled through optical fibers with acceptable performance in terms of energy and timing resolution and crystal identification. The PSAPD-LSO detector performs well in the 7-T magnet, and no visible artifacts are detected in the MR images using standard pulse sequences. The first images from the complete system have been successfully acquired and reconstructed, demonstrating that simultaneous PET and MRI studies are feasible and opening up interesting possibilities for dual-modality molecular imaging studies.

Focal thyroid incidentalomas identified with whole-body FDG-PET warrant further investigation.

LENUS (Irish Health Repository)

Prichard, R S

2012-02-01

Fluorodeoxyglucose (FDG) whole body positron emission computed tomography (PET-CT) detects clinically occult malignancy. The aim of this study was to assess the prevalence and significance of focal thyroid 18F - fluorodeoxyglucose uptake. A retrospective review of all patients who had FDG PET-CT examinations, in a single tertiary referral centre was performed. PET scan findings and the final pathological diagnosis were collated. 2105 scans were reviewed. Focal uptake was identified in 35 (1.66%) patients. Final surgical histology was available on eight patients, which confirmed papillary carcinoma in four (20%) patients and lymphoma and metastatic disease in two patients respectively. This gave an overall malignancy rate in focal thyroid uptake of at least 33%. Thyroid incidentalomas occurred with a frequency of 2.13%, with an associated malignancy rate of at least 33% in focal thyroid uptake. The high malignancy rate associated with focal thyroid uptake mandates further investigation in medically fit patients.

A count rate model for PET and its application to an LSO HR PLUS scanner

International Nuclear Information System (INIS)

Moisan, C.; Rogers, J.G.; Douglas, J.L.

1996-10-01

We present a count rate model for PET. Considering a standard 20 x 20 cm phantom in the field-of-view of a cylindrical septaless tomograph, the model computes the acceptance to prompt and random events from simple geometric considerations. Dead time factors at all stages of a typical event acquisition architecture are calculated from specified processing clock cycles. Validations of the model's predictions against the measured performances of the ECAT-953B and the EXACT HR PLUS are presented. The model is then used to investigate the benefit of using detectors made of LSO in the EXACT HR PLUS scanner geometry. The results indicate that in replacing BGO by the faster LSO, one can count on an increase of the peak noise-equivalent-count rate by a factor 2.2. This gain will be achieved by using a 5 nsec coincidence window, buckets operating on 128 nsec clock cycle, and front-end data acquisition that can sustain a total rate of 2.9 MHz. (authors)

Another breed of "service" animals: STARS study findings about pet ownership and recovery from serious mental illness.

Science.gov (United States)

Wisdom, Jennifer P; Saedi, Goal Auzeen; Green, Carla A

2009-07-01

This study elucidates the role of pets in recovery processes among adults with serious mental illness. Data derive from interviews with 177 HMO members with serious mental illness (52.2% women, average age 48.8 years) in the Study of Transitions and Recovery Strategies (STARS). Interviews and questionnaires addressed factors affecting recovery processes and included questions about pet ownership. Data were analyzed using a modified grounded theory method to identify the roles pets play in the recovery process. Primary themes indicate pets assist individuals in recovery from serious mental illness by (a) providing empathy and "therapy"; (b) providing connections that can assist in redeveloping social avenues; (c) serving as "family" in the absence of or in addition to human family members; and (d) supporting self-efficacy and strengthening a sense of empowerment. Pets appear to provide more benefits than merely companionship. Participants' reports of pet-related contributions to their well-being provide impetus to conduct more formal research on the mechanisms by which pets contribute to recovery and to develop pet-based interventions.

Dual cardiac-respiratory gated PET: implementation and results from a feasibility study

International Nuclear Information System (INIS)

Martinez-Moeller, Axel; Zikic, Darko; Navab, Nassir; Botnar, Rene M.; Bundschuh, Ralph A.; Ziegler, Sibylle I.; Schwaiger, Markus; Nekolla, Stephan G.; Howe, William

2007-01-01

Spatial resolution in myocardial imaging is impaired by both cardiac and respiratory motion owing to motional blurring. We investigated the feasibility of a dual cardiac-respiratory gated positron emission tomography (PET) acquisition using a clinical PET/computer tomography (CT) scanner. We describe its implementation and present results on the respiratory motion observed. The correlation between diaphragmatic excursion measured by real-time magnetic resonance imaging (MRI) and the expansion of the chest measured with an elastic belt was studied in six subjects. PET list mode acquisitions were then performed in 12 patients, six of them injected with 13 N-ammonia and six with 18 F-FDG. In parallel, the ECG and respiratory signals of the patients were recorded and the list mode file correspondingly sorted using a dual gated approach. Respiratory motion of the heart was quantified by measuring the displacement between the inspiratory and expiratory images in the diastolic phase by means of intensity-based non-rigid image registration. The correlation between diaphragmatic excursion and expansion of the chest was excellent (R 2 = 0.91), validating the ability of the elastic belt to provide an adequate respiratory trigger. Respiratory signals corresponding to the chest expansion showed a large inter-patient variability, requiring adapted algorithms in order to define suitable respiratory gates. Dual gated PET series were successfully acquired for both groups of patients, showing better resolved myocardial walls. The average respiratory motion of the heart measured by PET was 4.8 mm, with its largest component in the craniocaudal direction. Moreover, a deformation of the heart with respiration was observed, with the inferior wall moving significantly more than the anterior. Dual gated cardiac PET studies were performed successfully and showed better resolved myocardial walls as compared with ungated acquisitions. The respiratory motion of the heart presented a

{sup 18}F-FDOPA PET/CT imaging of insulinoma revisited

Energy Technology Data Exchange (ETDEWEB)

Imperiale, Alessio; Namer, Izzie-Jacques [University Hospitals of Strasbourg, Department of Biophysics and Nuclear Medicine, Strasbourg (France); University of Strasbourg/CNRS and FMTS, Faculty of Medicine, ICube - UMR 7357, Strasbourg (France); Sebag, Frederic [Aix-Marseille University, Department of Endocrine Surgery, La Timone University Hospital, Marseille (France); Vix, Michel [University of Strasbourg, Department of General, Digestive, and Endocrine Surgery, IRCAD-IHU, Strasbourg (France); Castinetti, Frederic [Aix-Marseille University, Department of Endocrinology, Diabetes and Metabolic Disorders, La Timone University Hospital, Marseille (France); Kessler, Laurence; Moreau, Francois [University of Strasbourg, Department of Diabetology, University Hospital of Strasbourg, Strasbourg (France); Bachellier, Philippe [University Hospitals of Strasbourg, Department of Visceral Surgery and Transplantation, Strasbourg (France); Guillet, Benjamin; Mundler, Olivier [Aix-Marseille University, Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Marseille (France); Taieb, David [Aix-Marseille University, Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Marseille (France); Aix-Marseille University, Biophysics and Nuclear Medecine, La Timone University Hospital, European Center for Research in Medical Imaging, Marseille (France)

2014-11-01

{sup 18}F-FDOPA PET imaging is increasingly used in the work-up of patients with neuroendocrine tumours. It has been shown to be of limited value in localizing pancreatic insulin-secreting tumours in adults with hyperinsulinaemic hypoglycaemia (HH) mainly due to {sup 18}F-FDOPA uptake by the whole pancreatic gland. The objective of this study was to review our experience with {sup 18}F-FDOPA PET/CT imaging with carbidopa (CD) premedication in patients with HH in comparison with PET/CT studies performed without CD premedication in an independent population. A retrospective study including 16 HH patients who were investigated between January 2011 and December 2013 using {sup 18}F-FDOPA PET/CT (17 examinations) in two academic endocrine tumour centres was conducted. All PET/CT examinations were performed under CD premedication (200 mg orally, 1 - 2 h prior to tracer injection). The PET/CT acquisition protocol included an early acquisition (5 min after {sup 18}F-FDOPA injection) centred over the upper abdomen and a delayed whole-body acquisition starting 20 - 30 min later. An independent series of eight consecutive patients with HH and investigated before 2011 were considered for comparison. All patients had a reference whole-body PET/CT scan performed about 1 h after {sup 18}F-FDOPA injection. In all cases, PET/CT was performed without CD premedication. In the study group, {sup 18}F-FDOPA PET/CT with CD premedication was positive in 8 out of 11 patients with histologically proven insulinoma (73 %). All {sup 18}F-FDOPA PET/CT-avid insulinomas were detected on early images and 5 of 11 (45 %) on delayed ones. The tumour/normal pancreas uptake ratio was not significantly different between early and delayed acquisitions. Considering all patients with HH, including those without imaging evidence of disease, the detection rate of the primary lesions using CD-assisted {sup 18}F-FDOPA PET/CT was 53 %, showing 9 insulinomas in 17 studies performed. In the control group (without

A prospective multi-centre study of the value of FDG-PET as part of a structured diagnostic protocol in patients with fever of unknown origin

International Nuclear Information System (INIS)

Bleeker-Rovers, Chantal P.; Vos, Fidel J.; Meer, Jos W.M. van der; Mudde, Aart H.; Dofferhoff, Anton S.M.; Geus-Oei, Lioe-Fee de; Rijnders, Anton J.; Krabbe, Paul F.M.; Corstens, Frans H.M.; Oyen, Wim J.G.

2007-01-01

Since 18 F-fluorodeoxyglucose (FDG) accumulates in neoplastic cells and in activated inflammatory cells, positron emission tomography (PET) with FDG could be valuable in diagnosing patients with fever of unknown origin (FUO). The aim of this study was to validate the use of FDG-PET as part of a structured diagnostic protocol in the general patient population with FUO. From December 2003 to July 2005, 70 patients with FUO were recruited from one university hospital (n=38) and five community hospitals (n=32). A structured diagnostic protocol including FDG-PET was used. A dedicated, full-ring PET scanner was used for data acquisition. FDG-PET scans were interpreted by two staff members of the department of nuclear medicine without further clinical information. The final clinical diagnosis was used for comparison with the FDG-PET results. Of all scans, 33% were clinically helpful. The contribution of FDG-PET to the final diagnosis did not differ significantly between patients diagnosed in the university hospital and patients diagnosed in the community hospitals. FDG-PET contributed significantly more often to the final diagnosis in patients with continuous fever than in patients with periodic fever. FDG-PET was not helpful in any of the patients with normal erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). FDG-PET is a valuable imaging technique as part of a diagnostic protocol in the general patient population with FUO and a raised ESR or CRP. (orig.)

Assessing FDG-PET diagnostic accuracy studies to develop recommendations for clinical use in dementia.

Science.gov (United States)