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BACKGROUND Information on scintigraphy findings in dogs with thyroid neoplasia is scarce. The use of single-photon emission computed tomography (SPECT) could improve detection of metastatic disease. HYPOTHESIS/OBJECTIVES To describe planar and SPECT imaging findings in dogs with thyroid tumors, and to compare SPECT and thoracic radiography for metastasis detection. ANIMALS Sixty-eight dogs with thyroid neoplasia. METHODS Retrospective study, search of medical records for dogs with thyroid neoplasia (2008-2018). RESULTS Thyroid scintigraphy was available from 68 dogs, of which 6 presented after surgical resection. Radionuclide uptake was increased in 56% of dogs, decreased in 24%, and comparable to that of the salivary glands in 13%. The remainder had multiple masses with variable uptake. A homogeneous uptake pattern was present in 16% and a heterogeneous uptake pattern in 73%. In 11% (all dogs with multiple masses), various uptake patterns were present. Thyroid tumors were well delineated in 55%. There was a significant association between hormone status and uptake pattern (P = .009), with a heterogeneous uptake pattern in the majority of euthyroid dogs, and hormone status and tumor circumscription (P = .003), with well-circumscribed margins in the majority of hypothyroid and hyperthyroid dogs. Thoracic SPECT imaging was available in 39 dogs and identified metastatic lesions in 15 dogs. Thoracic radiographs were performed in 14 of these dogs, and detected metastases in 3 dogs. CONCLUSIONS AND CLINICAL IMPORTANCE SPECT imaging is a viable imaging technique to screen for thoracic metastasis and wider use of SPECT imaging is recommended in dogs with thyroid neoplasia.

Objectives An electronic training programme (ETP) was developed for interpretation of images during routine clinical use of the PET amyloid imaging agent [18F] flutemetamol injection (VIZAMYL). This study was carried out to validate the ETP.Materials and methods Five nuclear medicine technologists (NMTs) and five readers previously inexperienced in amyloid image interpretation were required to self-train using the ETP and pass a test to participate. A total of 305 [18F] flutemetamol PET images were then tested as the validation set, following preassessment and reorientation (where required) by one of five NMTs. Next, a new set of readers blinded to clinical information independently assessed all 305 images. Images had been acquired in previous studies from patients representing the full spectrum of cognitive capacity. When available, a standard of truth determined by histopathology or clinical history was used to derive sensitivity and specificity for image interpretation from this validation set. Randomly selected images (n= 29) were read in duplicate to measure intrareader reproducibility. Images were read first without, and subsequently with anatomic images, if available.Results All NMTs and all readers scored 100% on the qualifying test. The interpretation of 135 cases without anatomic image support resulted in sensitivity ranging from 84% to 94% (majority 94%, median 92%) and specificity ranging from 77% to 96% (majority 92%, median 81%). Inter-reader agreement was very high, with most kappa scores more than 0.8. Intrareader reproducibility ranged from 93 to 100%.Conclusion The self-guided ETP effectively trained new amyloid PET image readers to accurately and reproducibly interpret [F-18] flutemetamol PET images. Nucl Med Commun 38:234-241 Copyright (C) 2017 The Author(s). Published by Wolters Kluwer Health, Inc.

Background: Diagnosing diabetic foot infection is often difficult, despite several available diagnostic methods. Amongst these, several imaging modalities exist to evaluate the diabetic foot in case of a suspected osteomyelitis. Nuclear Medicine, in particular, offers a variety of radiopharmaceuticals and techniques. Nowadays the gold standard radionuclide procedure, when an osteomyelitis is suspected, is represented by the use of radiolabelled leukocytes with either 99mTc-HMPAO or 111In-oxine. Methods: : In this review, we describe the correct acquisition and interpretation of white blood cell scintigraphy and we provide an overview of the existing literature data of the use of this technique in the infected diabetic foot. If images are correctly acquired, displayed and interpreted, this modality reaches very high diagnostic accuracy (>95%) in detecting osteomyelitis and it allows the differential diagnosis with a soft tissue infection or inflammation. Single-photon emission computed tomography/computed tomography (SPECT/CT) in addition to planar images is mandatory to determine the extent and exact location of the infective process in both fore foot and midhint foot. With the addition of bone marrow scintigraphy using radiolabelled nanocolloids, radiolabelled white blood cell scintigraphy is also able to differentiate between Charcot neuroarthropathy and osteomyelitis, which is a challenge in the evaluation of diabetic foot. Radiolabelled anti-granulocyte monoclonal antibodies and their fragments can also be used instead of white blood cells although there is a limited experience on their usefulness in diabetic foot infection.

International audience; The project "Metrology for molecular radiotherapy" is a collaborative European project initiated to bring together expertize in ionizing radiation metrology and nuclear medicine research. This project deals with the development of personalized dosimetry to individual patients who are undergoing molecular radiotherapy (also known as targeted radionuclide therapy). The general aim is to provide a metrological traceability to primary standards for individual dosimetry in the case of molecular radiotherapy. In particular, one objective is the standardization of Y-90-labeled resin microspheres SIR-Spheres (Sirtex, Sydney, Australia) used for the treatment of liver cancer by radioembolization. The present paper describes the primary measurements carried out using the Triple to Double Coincidence Ratio (TDCR) method applied after the complete dissolution of the SIR-Spheres in the Sirtex vial. A method for the dissolution was developed to optimize the homogeneity of the solution to enable the primary measurements based on Cherenkov and liquid scintillation counting. A comprehensive description of the protocol implemented for the microsphere dissolution is reported. First calibration factors obtained with the reference ionization chambers at LNE-LNHB are also given.

Ga-68-pentixafor is a radiotracer for PET that binds with nanomolar affinity to CXCR4. The CXCR4 receptor is expressed at the surface of inflammatory cells. The objective of the study was to analyze the ability of radiolabeled pentixafor to detect CXCR4 expression on inflammatory cells present in atherosclerotic plaques of an experimental rabbit model. Methods: Atherosclerotic plaques were induced by endothelial abrasion of the right carotid artery and abdominal aorta of 7 rabbits fed an atherogenic diet. Five noninjured rabbits fed a chow diet were used as controls. Rabbits were imaged on a PET/MR system after injection of Ga-68-pentixafor (15 MBq/kg). Vascular signal was quantified as tissue-to-background ratio (TBR). Biodistribution and autoradiographic studies were performed 1 h after injection of I-125-pentixafor (7.5 MBq/kg). In addition, blocking studies were performed in 2 atherosclerotic rabbits with preinjection of the CXCR4 inhibitor AMD3100. Tracer uptake was quantified on arterial cryosections using autoradiography and compared with CXCR4 and RAM-11 (macrophage) expression on adjacent histologic sections. Results: One hour after injection of Ga-68-pentixafor, strong signals were detected in vivo with PET/MR imaging in atherosclerotic plaques of the abdominal aorta and right carotid artery as compared with normal control arteries (mean TBR 5 1.95 +/- 0.51 vs. 1.22 +/- 0.25 and mean TBR 5 1.24 +/- 0.38 vs. 0.96 +/- 0.37, respectively; P

Purpose: The rapid growth and usage of small animal positron emission tomography (PET) in molecular imaging research has led to increased demand on PET scanner's time. One potential solution to increase throughput is to scan multiple rodents simultaneously. However this is achieved at the expense of deterioration of image quality and loss of quantitative accuracy owing to enhanced effects of photon attenuation and Compton scattering. The purpose of this work is first to characterize the magnitude and spatial distribution of the scatter component in small animal PET imaging when scanning single and multiple rodents simultaneously and second to assess the relevance and evaluate the performance of scatter correction under similar conditions. Methods: The LabPET™ 8 scanner was modelled as realistically as possible using Geant4 Application for Tomographic Emission Monte Carlo simulation platform. Monte Carlo simulations allow the separation of unscattered and scattered coincidences and as such enable detailed assessment of the scatter component and its origin. Simple shape based and more realistic voxel based phantoms were used to simulate single and multiple PET imaging studies. The modelled scatter component using the single scatter simulation technique was compared to Monte Carlo simulation results. PET images were also corrected for attenuation and the combined effect of attenuation and scatter on single and multiple small animal PET imaging evaluated in terms of image quality and quantitative accuracy. Results: A good agreement was observed between calculated and Monte Carlo simulated scatter profiles for single and multiple subject imaging. In the LabPET™ 8 scanner the detector covering material (kovar) contributed the maximum amount of scatter events while the scatter contribution due to lead shielding is negligible. The out of field of view (FOV) scatter fraction (SF) is 1.70 0.76 and 0.11 for lower energy thresholds of 250 350 and 400 keV respectively. The increase in SF ranged between 25 and 64 when imaging multiple subjects (three to five) of different size simultaneously in comparison to imaging a single subject. The spill over ratio (SOR) increases with increasing the number of subjects in the FOV. Scatter correction improved the SOR for both water and air cold compartments of single and multiple imaging studies. The recovery coefficients for different body parts of the mouse whole body and rat whole body anatomical models were improved for multiple imaging studies following scatter correction. Conclusions: The magnitude and spatial distribution of the scatter component in small animal PET imaging of single and multiple subjects simultaneously were characterized and its impact was evaluated in different situations. Scatter correction improves PET image quality and quantitative accuracy for single rat and simultaneous multiple mice and rat imaging studies whereas its impact is insignificant in single mouse imaging. © 2013 World Molecular Imaging Society.

There has been a significant increase in the number of joint prosthesis replacements worldwide. Although relatively uncommon, complications can occur with the most serious being an infection. Various radiological and nuclear imaging techniques are available to diagnose prosthetic joint infections (PJI). In this review article, we describe the pathophysiology of PJI, the principles of nuclear medicine imaging and the differences between Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). The value of nuclear medicine techniques for clinical practice is also discussed. Then we provide an overview of the most often used radionuclide imaging techniques that may be helpful in diagnosing prosthetic joint infection: the (67)Ga-citrate, labelled white blood cells in vitro and in vivo (monoclonal antibodies directed against specific targets on the leukocytes), and (18)F-fluorodeoxyglucose ((18)F-FDG). We describe their working methods, the pitfalls, and the interpretation criteria. Furthermore, we review recent advances in imaging bacteria, a molecular imaging method that holds promises for the detection of occult infections. We conclude proposing two diagnostic flow-charts, based on data in the literature, that could help the clinicians to choose the best nuclear imaging method when they have a patient with suspicion of or with proven PJI.

The cannabinoid type-1 (CB1) receptor is one of the most abundant G-coupled protein receptors in the human body and is responsible for signal transduction of both endogenous and exogenous cannabinoids. The endocannabinoid system is strongly implicated in regulation of homeostasis and several neuropsychiatric disorders, obesity, and associated comorbidities, such as dyslipidemia and metabolic syndrome. We have used whole-body PET/CT to characterize the biodistribution and dosimetry of a novel high-affinity, subtype-selective radioligand, F-18-MK-9470, in healthy male and female subjects. Methods: Eight nonobese subjects (5 men, 3 women; age, 22-54 y) underwent serial whole-body PET/CT for 6 h after a bolus injection of 251 +/- 25 MBq F-18-MK-9470 (N-[2-(3-cyano-phenyl)-3-(4-(2-F-18-fluorethoxy)phenyl)-1-methylpropyl]-2-(5-methyl-2-pyridyloxy)-2-methylproponamide). Source organs were delineated 3-dimensionally using the combined morphologic and functional data. Residence times were derived from time-activity profiles using both the trapezoid rule and curve fitting. Individual organ doses and effective doses were determined using the OLINDA software package, with different approaches for gastrointestinal and urinary excretion modeling. Results: F-18-MK-9470 is taken up slowly in the brain, reaching a plateau at approximately 90-120 min after bolus injection and is excreted predominantly through the hepatobiliary system. The gallbladder, upper large intestine, small intestine, and liver are the organs with the highest absorbed dose (average: 159, 98, 87 and 86 mu Gy/MBq, respectively). The mean effective dose (ED) was 22.8 +/- 4.3 mu Sv/MBq, indicating relatively low intersubject variability and a mean value in the range of many commercially available F-18-labeled radiopharmaceuticals. Brain uptake was relatively high compared with that of existing central nervous system ligands for other receptors, between 3.2% and 4.9% of the injected dose. Conclusion: The estimated radiation bur-den of F-18-MK-9470 for PET CB1 receptor imaging shows relatively low variability between subjects and has an acceptable ED, which allows multiple serial cerebral scans of good image quality, while remaining within the risk category class II-b defined by the World Health Organization and the International Commission for Radiation Protection for a standard injected activity (185-370 MBq). ispartof: Journal of Nuclear Medicine vol:49 issue:3 pages:439-445 ispartof: location:United States status: published

1Nuclear Medicine Unit, Department of Medical-Surgical Sciences and Translational Medicine, Faculty of Medicine and Psychology, Ospedale S. Andrea, “Sapienza” University, Via di Grottarossa 1035, 00189 Roma, Italy 2Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen University of Groningen, Hanzeplein 1, 9700 RB Groningen, Netherlands 3Nuclear Medicine Department, Bichat-Claude Bernard Hospital and Paris Diderot University, 46 Rue Henri Huchard, 75018 Paris, France

PET uses specific molecules labelled with positron-emitting radionuclides to provide valuable biochemical and physiological information. However, the administration of radiotracers to patients exposes them to low-dose ionizing radiation, which is a concern in the paediatric population since children are at a higher cancer risk from radiation exposure than adults. Therefore, radiation dosimety calculations for commonly used positron-emitting radiotracers in the paediatric population are highly desired. We evaluate the absorbed dose and effective dose for 19 positron-emitting labelled radiotracers in anthropomorphic paediatric models including the newborn, 1-, 5-, 10- and 15-year-old male and female. This is achieved using pre-calculated S-values of positron-emitting radionuclides of UF-NCI paediatric phantoms and published biokinetic data for various radiotracers. The influence of the type of anthropomorphic model, tissue weight factors and direct human-versus mouse-derived biokinetic data on the effective dose for paediatric phantoms was also evaluated. In the case of F-18-FDG, dosimetry calculations of reference paediatric patients from various dose regimens were also calculated. Among the considered radiotracers, F-18-FBPA and O-15-water resulted in the highest and lowest effective dose in the paediatric phantoms, respectively. The ICRP 103 updated tissue-weighting factors decrease the effective dose in most cases. Substantial differences of radiation dose were observed between direct human-versus mouse-derived biokinetic data. Moreover, the effect of using voxel-versus MIRD-type models on the calculation of the effective dose was also studied. The generated database of absorbed organ dose and effective dose for various positron-emitting labelled radiotracers using new generation computational models and the new ICRP tissue-weighting factors can be used for the assessment of radiation risks to paediatric patients in clinical practice. This work also contributes to a better understanding of the factors influencing patient-specific radiation dose calculation.

Ziel: Zur Darstellung von Integrin αvβ3 von Tumoren oder Tumorneugefäßen wählten wir das zyklische Bindungspeptid Arg-Gly-Asp-D-Tyr-Lys (RGDyK) gekoppelt an NODAGA zur Markierung mit 68Ga. Methoden: NODAGA-RGDyK (ABX) wurde mit dem 68Ga-Eluat des 68Ge-Generators IGG100 markiert mit der Prozessoreinheit PharmTracer. Bioverteilungen wurden in weiblichen Hsd-Mäusen 10, 30, 60 und 90 min nach i.v.-Injektion von 68Ga-NODAGA-RGDyK gemessen und als OLINDA-Dosimetrie auf den Menschen projiziert. In SCID-Mäusen, die A431 und andere Tumoren trugen, wurde die Tumoraufnahme mit microPET und Bioverteilungen studiert. Ergebnisse: Die effektive Halbwertszeit von 68Ga-NODAGA-RGDyK war ~25 min im Ganzkörper und den meisten Organen außer Leber und Milz, für die eine stabile Aufnahme gemessen wurde. Die für Frauen und Männer berechnete effektive Dosis (ED) war 0.012 bzw. 0.016 mSv/MBq mit der Annahme eines Blasenleerungsintervalls von 0.5 h. Mit dynamischem PET wurde eine rasche A431-Tumoraufnahme innerhalb von 10 Minuten beobachtet, gefolgt von einem langsamen Abfluss. Bioverteilungen zeigten eine A431-Tumoraufnahme von 68Ga-NODAGA-RGDyK von 3.4±0.4 und 2.7±0.3%ID/g nach 1 bzw. 2 Stunden. Ähnliche Tumoranreicherungen in der Maus wurden in einem Maus- und Humanbrustkrebs gemessen sowie in humanem Ovarialkrebs. Co-Injektion mit einer Überdosis (5 mg/kg) unmarkiertem NODAGA-RGDyK mit dem Radiopharmazeutikum reduzierte die Tumoraufnahme auf 0.23±0.01%ID/g nach 1 Stunde, jedoch wurde eine ähnlich reduzierte Aufnahme auch in andern normalen Organen beobachtet. Wenn unmarkiertes Peptid 15 min nach 68Ga-NODAGA-RGDyK injiziert wurde, verminderte sich die Aufnahme besonders in Tumor und Nebennieren. Diese Beobachtung kann im Vergleich zu anderen Normalgeweben als unterschiedliches Bindungsverhalten gedeutet werden. Schlussfolgerung: NODAGA-RGDyK konnte zuverlässig mit 68Ga markiert werden und zeigte für Menschen eine vorhergesagte ED von 0.014 mSv/MBq. Die Tumoranreicherung war schnell und signifikant. Sie wurde aus Tumor und Nebennieren durch nachgespritztes, unmarkiertes NODAGA-RGDyK in ähnlicher Weise verdrängt. Aim: To visualize neovasculature and/or tumour integrin αvβ3 we selected the binding moiety Arg-Gly-Asp-D-Tyr-Lys (RGDyK) coupled to NODAGA for labeling with 68Ga. Methods: NODAGA-RGDyK (ABX) was labeled with the 68Ga eluate from the 68Ge generator IGG100 using the processor unit PharmTracer. Biodistribution was measured in female Hsd mice sacrificed 10, 30, 60 and 90 min after i.v. injection of 68Ga-NODAGA-RGDyK for OLINDA dosimetry extrapolated to humans. Tumour targeting was studied in SCID mice bearing A431 and other tumour transplants using microPET and biodistribution measurements. Results: Effective half-life of 68Ga-NODAGA-RGDyK was ~25 min for total body and most organs except liver and spleen that showed stable activity retention. With a bladder voiding interval of 0.5 h the calculated effective dose (ED) was 0.012 and 0.016 mSv/MBq for males and females, respectively. Rapid uptake within 10 min was observed in A431 tumours with dynamic PET followed by a slow release. Biodistribution measurements showed a 68Ga-NODAGA-RGDyK uptake in A431 tumours of 3.4±0.4 and 2.7±0.3%ID/g at 1 and 2 h, respectively. Similar uptakes were observed in a mouse and human breast and ovarian cancer xenografts. Co-injection of excess (5 mg/kg) unlabeled NODAGA-RGDyK with the radiotracer reduced tumour uptake at one hour to 0.23±0.01%ID/g, but similarly decreased uptake in normal organs as well. When unlabeled peptide was injected 15 min after 68Ga-NODAGA-RGDyK, uptake diminished particularly in tumour and adrenals, suggestive of a different binding mode compared with other normal tissues. Conclusion: NODAGA-RGDyK was reliably labeled with 68Ga and revealed a predicted ED of 0.014 mSv/MBq. Tumour uptake was rapid and significant and was chased with unlabeled RGDyK in a similar manner as adrenal uptake.

This study aimed to estimate the radiation absorbed doses to normal tissues and tumor lesions during radioimmunotherapy with (177)Lu-cG250. Serial planar scintigrams after injection of (111)In-cG250 or (177)Lu-cG250 in patients with metastasized renal cell carcinoma were analyzed quantitatively. The estimated radiation doses were correlated with observed hematologic toxicity. In addition, the accuracy of the predicted therapeutic absorbed doses, based on diagnostic (111)In-cG250 data, were determined.METHODS:Twenty patients received a diagnostic tracer activity of (111)In-cG250 (185 MBq), followed by radioimmunotherapy with (177)Lu-cG250. The administered activity of (177)Lu-cG250 was escalated by entering 3 patients at each activity level starting at 1,110 MBq/m(2), with increments of 370 MBq/m(2). After each diagnostic and therapeutic administration, whole-body scintigraphic images and pharmacokinetic data were acquired. Hematologic toxicity was graded using the Common Toxicity Criteria, version 3.0. Diagnostic (111)In-cG250 data were used to simulate (177)Lu and (90)Y data by correcting for the difference in physical decay. Absorbed doses were calculated for the whole body, red marrow, organs, and tumor metastases for the therapeutic (177)Lu-cG250, simulated (177)Lu-cG250, and simulated (90)Y-cG250 data.RESULTS:Observed hematologic toxicity, especially platelet toxicity, correlated significantly with the administered activity (r = 0.85), whole-body absorbed dose (r = 0.65), and red marrow dose (r = 0.62 and 0.75). An inverse relationship between the mass and absorbed dose of the tumor lesions was observed. Calculated mean absorbed doses were similar for the simulated and measured (177)Lu-cG250 data. Absorbed doses (whole body and red marrow) based on the simulated (177)Lu-cG250 data correlated with the observed platelet toxicity (r = 0.65 and 0.82). The tumor-to-red marrow dose ratio was higher for radioimmunotherapy with (177)Lu-cG250 than for radioimmunotherapy with (90)Y-cG250, indicating that (177)Lu has a wider therapeutic window for radioimmunotherapy with cG250 than (90)Y.CONCLUSION:In patients with metastasized renal cell carcinoma, hematologic toxicity after treatment with (177)Lu-cG250 can be predicted on the basis of administered activity and whole-body and red marrow-absorbed dose. Diagnostic (111)In-cG250 data can be used to accurately predict absorbed doses and myelotoxicity of radioimmunotherapy with (177)Lu-cG250. These estimations indicate that in these patients, higher radiation doses can be guided to the tumors with (177)Lu-cG250 than with (90)Y-cG250.

TO THE EDITOR: In a recent issue of The Journal Nuclear Medicine, 2 interesting papers on PET detection of epidermal growth factor receptor (EGFR) in cancer were published ( [1][1],[2][2] ). Liu et al. reported the potential of 11C-PD153035 for the imaging of EGFR expression in humans, especially in