Purpose To describe the pharmacokinetic properties of the [ 18F]fuoro-polyethylene glycol(PEG)-folate radiotracer in PET/ CT imaging of patients with advanced stage epithelial ovarian cancer (EOC).... Show morePurpose To describe the pharmacokinetic properties of the [ 18F]fuoro-polyethylene glycol(PEG)-folate radiotracer in PET/ CT imaging of patients with advanced stage epithelial ovarian cancer (EOC). Procedures In fve patients with advanced EOC (FIGO stage IIIB/IIIC, Fédération Internationale de Gynécologie et d’Obstétrique), a 90-min dynamic PET acquisition of the pelvis was performed directly after i.v. administration of 185 MBq [ 18F]fuoro-PEG6-folate. Arterial blood samples collected at nineteen timepoints were used to determine the plasma input function. A static volume of interest (VOI) for included tumor lesions was drawn manually on the PET images. Modelling was performed using PMOD software. Three diferent models (a 1-tissue compartment model (1T2k) and two 2-tissue compartment models, irreversible (2T3k) and reversible (2T4k)) were compared in goodness of ft with the time activity curves by means of the Akaike information criterion. Results The pharmacokinetic analysis in the pelvic area has proven to be much more challenging than expected. Only four out of 22 tumor lesions in fve patients were considered suitable to perform modelling on. The remaining tumor lesions were inapt due to either low tracer uptake, small size, proximity to other [ 18F]fuoro-PEG6-folate -avid structures and/or displacement by abdominal organ motion in the dynamic scan. Data from the four analyzed tumor lesions suggest that the irreversible 2T3k may best describe the pharmacokinetics. All 22 lesions were immunohistochemically stained positive for the folate receptor alpha (FRα) after resection. Conclusion Performing pharmacokinetic analysis in the abdominal pelvic region is very challenging. This brief article describes the challenges and pitfalls in pharmacokinetic analysis of a tracer with high physiological accumulation in the intestines, in case of lesions of limited size in the abdominal pelvic area. Show less
PurposeFluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed... Show morePurposeFluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed ankyrin repeat proteins (DARPins) possess optimal pharmacokinetic and other properties for in vivo imaging. This study aims to evaluate the preclinical potential of epithelial cell adhesion molecule (EpCAM)-binding DARPins as targeting moieties for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of cancer.MethodsEpCAM-binding DARPins Ac2, Ec4.1, and non-binding control DARPin Off7 were conjugated to IRDye 800CW and their binding efficacy was evaluated on EpCAM-positive HT-29 and EpCAM-negative COLO-320 human colon cancer cell lines. Thereafter, NIRF and PA imaging of all three conjugates were performed in HT-29_luc2 tumor-bearing mice. At 24 h post-injection, tumors and organs were resected and tracer biodistributions were analyzed.ResultsAc2-800CW and Ec4.1-800CW specifically bound to HT-29 cells, but not to COLO-320 cells. Next, 6 nmol and 24 h were established as the optimal in vivo dose and imaging time point for both DARPin tracers. At 24 h post-injection, mean tumor-to-background ratios of 2.60 & PLUSMN; 0.3 and 3.1 & PLUSMN; 0.3 were observed for Ac2-800CW and Ec4.1-800CW, respectively, allowing clear tumor delineation using the clinical Artemis NIRF imager. Biodistribution analyses in non-neoplastic tissue solely showed high fluorescence signal in the liver and kidney, which reflects the clearance of the DARPin tracers.ConclusionOur encouraging results show that EpCAM-binding DARPins are a promising class of targeting moieties for pan-carcinoma targeting, providing clear tumor delineation at 24 h post-injection. The work described provides the preclinical foundation for DARPin-based bimodal NIRF/PA imaging of cancer. Show less
Fluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed... Show moreFluorescence-guided surgery (FGS) can play a key role in improving radical resection rates by assisting surgeons to gain adequate visualization of malignant tissue intraoperatively. Designed ankyrin repeat proteins (DARPins) possess optimal pharmacokinetic and other properties for in vivo imaging. This study aims to evaluate the preclinical potential of epithelial cell adhesion molecule (EpCAM)-binding DARPins as targeting moieties for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of cancer. EpCAM-binding DARPins Ac2, Ec4.1, and non-binding control DARPin Off7 were conjugated to IRDye 800CW and their binding efficacy was evaluated on EpCAM-positive HT-29 and EpCAM-negative COLO-320 human colon cancer cell lines. Thereafter, NIRF and PA imaging of all three conjugates were performed in HT-29_luc2 tumor-bearing mice. At 24 h post-injection, tumors and organs were resected and tracer biodistributions were analyzed. Ac2-800CW and Ec4.1-800CW specifically bound to HT-29 cells, but not to COLO-320 cells. Next, 6 nmol and 24 h were established as the optimal in vivo dose and imaging time point for both DARPin tracers. At 24 h post-injection, mean tumor-to-background ratios of 2.60 ± 0.3 and 3.1 ± 0.3 were observed for Ac2-800CW and Ec4.1-800CW, respectively, allowing clear tumor delineation using the clinical Artemis NIRF imager. Biodistribution analyses in non-neoplastic tissue solely showed high fluorescence signal in the liver and kidney, which reflects the clearance of the DARPin tracers. Our encouraging results show that EpCAM-binding DARPins are a promising class of targeting moieties for pan-carcinoma targeting, providing clear tumor delineation at 24 h post-injection. The work described provides the preclinical foundation for DARPin-based bimodal NIRF/PA imaging of cancer. Show less
PurposeMetastasectomy is a common treatment option for patients with colorectal lung metastases (CLM). Challenges exist with margin assessment and identification of small nodules, especially during... Show morePurposeMetastasectomy is a common treatment option for patients with colorectal lung metastases (CLM). Challenges exist with margin assessment and identification of small nodules, especially during minimally invasive surgery. Intraoperative fluorescence imaging has the potential to overcome these challenges. The aim of this study was to assess feasibility of targeting CLM with the carcinoembryonic antigen (CEA) specific fluorescent tracer SGM-101.MethodsThis was a prospective, open-label feasibility study. The primary outcome was the number of CLM that showed a true positive fluorescence signal with SGM-101. Fluorescence positive signal was defined as a signal-to-background ratio (SBR) ≥ 1.5. A secondary endpoint was the CEA expression in the colorectal lung metastases, assessed with the immunohistochemistry, and scored by the total immunostaining score.ResultsThirteen patients were included in this study. Positive fluorescence signal with in vivo, back table, and closed-field bread loaf imaging was observed in 31%, 45%, and 94% of the tumors respectively. Median SBRs for the three imaging modalities were 1.00 (IQR: 1.00–1.53), 1.45 (IQR: 1.00–1.89), and 4.81 (IQR: 2.70–7.41). All tumor lesions had a maximum total immunostaining score for CEA expression of 12/12.ConclusionThis study demonstrated the potential of fluorescence imaging of CLM with SGM-101. CEA expression was observed in all tumors, and closed-field imaging showed excellent CEA specific targeting of the tracer to the tumor nodules. The full potential of SGM-101 for in vivo detection of the tracer can be achieved with improved minimal invasive imaging systems and optimal patient selection. Show less
Aims: Arthroplasty surgery of the knee and hip is performed in two to three million patients an-nually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiot-ics, and... Show moreAims: Arthroplasty surgery of the knee and hip is performed in two to three million patients an-nually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiot-ics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria -specific hybrid tracer (99mTc-UBI29-41-Cy5) and its ability to visualize the bacterial load on fem-oral implants using clinical -grade image guidance methods. Methods: 99mTc-UBI29-41- Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cul-tured on femoral prostheses using fluorescence imaging and freehand single photon emis-sion CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria. Results: Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be com-plemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were iden-tified using imaging, which included 500 to 2,000 viable bacteria.Conclusion: The hybrid tracer99mTc-UBI29-41-Cy5 allowed effective bacterial staining. Qualitative real -time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Show less
Aims Arthroplasty surgery of the knee and hip is performed in two to three million patients an-nually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiot-ics, and... Show moreAims Arthroplasty surgery of the knee and hip is performed in two to three million patients an-nually. Periprosthetic joint infections occur in 4% of these patients. Debridement, antibiot-ics, and implant retention (DAIR) surgery aimed at cleaning the infected prosthesis often fails, subsequently requiring invasive revision of the complete prosthetic reconstruction. Infection-specific imaging may help to guide DAIR. In this study, we evaluated a bacteria -specific hybrid tracer (99mTc-UBI29-41-Cy5) and its ability to visualize the bacterial load on fem-oral implants using clinical -grade image guidance methods.Methods 99mTc-UBI29-41- Cy5 specificity for Stapylococcus aureus was assessed in vitro using fluorescence confocal imaging. Topical administration was used to highlight the location of S. aureus cul-tured on femoral prostheses using fluorescence imaging and freehand single photon emis-sion CT (fhSPECT) scans. Gamma counting and fhSPECT were used to quantify the bacterial load and monitor cleaning with chlorhexidine. Microbiological culturing helped to relate the imaging findings with the number of (remaining) bacteria.Results Bacteria could be effectively stained in vitro and on prostheses, irrespective of the presence of biofilm. Infected prostheses revealed bacterial presence on the transition zone between the head and neck, and in the screw hole. Qualitative 2D fluorescence images could be com-plemented with quantitative 3D fhSPECT scans. Despite thorough chlorhexidine treatments, 28% to 44% of the signal remained present in the locations of the infection that were iden-tified using imaging, which included 500 to 2,000 viable bacteria.Conclusion The hybrid tracer99mTc-UBI29-41-Cy5 allowed effective bacterial staining. Qualitative real -time fluorescence guidance could be effectively combined with nuclear imaging that enables quantitative monitoring of the effectiveness of cleaning strategies. Show less
Purpose: Intraoperative identification of lung tumors can be challenging. Tumor-targeted fluorescence-guided surgery can provide surgeons with a tool for real-time intraoperative tumor detection.... Show morePurpose: Intraoperative identification of lung tumors can be challenging. Tumor-targeted fluorescence-guided surgery can provide surgeons with a tool for real-time intraoperative tumor detection. This study evaluated cell surface biomarkers, partially selected via data-driven selection software, as potential targets for fluorescence-guided surgery in non-small cell lung cancers: adenocarcinomas (ADC), adenocarcinomas in situ (AIS), and squamous cell carcinomas (SCC). Procedures: Formalin-fixed paraffin-embedded tissue slides of resection specimens from 15 patients with ADC and 15 patients with SCC were used and compared to healthy tissue. Molecular targets were selected based on two strategies: (1) a data-driven selection using > 275 multi-omics databases, literature, and experimental evidence; and (2) the availability of a fluorescent targeting ligand in advanced stages of clinical development. The selected targets were carbonic anhydrase 9 (CAIX), collagen type XVII alpha 1 chain (collagen XVII), glucose transporter 1 (GLUT1), G protein-coupled receptor 87 (GPR87), transmembrane protease serine 4 (TMPRSS4), carcinoembryonic antigen (CEA), epithelial cell adhesion molecule (EpCAM), folate receptor alpha (FR alpha), integrin alpha v beta 6 (alpha v beta 6), and urokinase-type plasminogen activator receptor (uPAR). Tumor expression of these targets was assessed by immunohistochemical staining. A total immunostaining score (TIS, range 0-12), combining the percentage and intensity of stained cells, was calculated. The most promising targets in ADC were explored in six AIS tissue slides to explore its potential in non-palpable lesions. Results: Statistically significant differences in TIS between healthy lung and tumor tissue for ADC samples were found for CEA, EpCAM, FR alpha, alpha v beta 6, CAIX, collagen XVII, GLUT-1, and TMPRSS4, and of these, CEA, CAIX, and collagen XVII were also found in AIS. For SCC, EpCAM, uPAR, CAIX, collagen XVII, and GLUT-1 were found to be overexpressed. Conclusions: EpCAM, CAIX, and Collagen XVII were identified using concomitant use of data-driven selection software and clinical evidence as promising targets for intraoperative fluorescence imaging for both major subtypes of non-small cell lung carcinomas. Show less
Flexible high-definition white-light endoscopy is the current gold standard in screening for cancer and its precursor lesions in the gastrointestinal tract. However, miss rates are high, especially... Show moreFlexible high-definition white-light endoscopy is the current gold standard in screening for cancer and its precursor lesions in the gastrointestinal tract. However, miss rates are high, especially in populations at high risk for developing gastrointestinal cancer (e.g., inflammatory bowel disease, Lynch syndrome, or Barrett's esophagus) where lesions tend to be flat and subtle. Fluorescence molecular endoscopy (FME) enables intraluminal visualization of (pre)malignant lesions based on specific biomolecular features rather than morphology by using fluorescently labeled molecular probes that bind to specific molecular targets. This strategy has the potential to serve as a valuable tool for the clinician to improve endoscopic lesion detection and real-time clinical decision-making. This narrative review presents an overview of recent advances in FME, focusing on probe development, techniques, and clinical evidence. Future perspectives will also be addressed, such as the use of FME in patient stratification for targeted therapies and potential alliances with artificial intelligence. Key Messages center dot Fluorescence molecular endoscopy is a relatively new technology that enables safe and real-time endoscopic lesion visualization based on specific molecular features rather than on morphology, thereby adding a layer of information to endoscopy, like in PET-CT imaging. center dot Recently the transition from preclinical to clinical studies has been made, with promising results regarding enhancing detection of flat and subtle lesions in the colon and esophagus. However, clinical evidence needs to be strengthened by larger patient studies with stratified study designs. center dot In the future fluorescence molecular endoscopy could serve as a valuable tool in clinical workflows to improve detection in high-risk populations like patients with Barrett's esophagus, Lynch syndrome, and inflammatory bowel syndrome, where flat and subtle lesions tend to be malignant up to five times more often. center dot Fluorescence molecular endoscopy has the potential to assess therapy responsiveness in vivo for targeted therapies, thereby playing a role in personalizing medicine. center dot To further reduce high miss rates due to human and technical factors, joint application of artificial intelligence and fluorescence molecular endoscopy are likely to generate added value. Show less
Skin-penetrating parasites have something in common; they all need to evade the initial immune response in the skin in order to avoid being evicted by their hostile host and establish an infection.... Show moreSkin-penetrating parasites have something in common; they all need to evade the initial immune response in the skin in order to avoid being evicted by their hostile host and establish an infection. To do so, they are equipped with the necessary cunning stratagems. For example, they can act directly on immune cells to alter their function and they can optimize their migration patterns to their hostile environment. This thesis is aimed at unravelling those mechanisms. We study two devastating parasitic diseases: Malaria and Schistosomiasis. Both deadly and debilitating parasitic diseases, with over 200 million (malaria) and over 240 million (schistosomiasis) cases annually; the need for potent vaccines is evident. Whole weakened parasites can be used to vaccinate individuals against parasitic diseases like malaria. However, delivery of these parasites in the skin, as is commonly done in vaccinations, reduces their protectivity. We hypothesize that this reduction is caused by parasite-mediated immune-regulatory mechanisms that are initiated upon their first encounter with immune cells in the skin. We investigated whether skin penetrating parasites exploit these existing mechanisms in human skin in order to enhance their survival. Show less
Inflammatory musculoskeletal diseases represent a group of chronic and disabling conditions that evolve from a complex interplay between genetic and environmental factors that cause perturbations... Show moreInflammatory musculoskeletal diseases represent a group of chronic and disabling conditions that evolve from a complex interplay between genetic and environmental factors that cause perturbations in innate and adaptive immune responses. Understanding the pathogenesis of inflammatory musculoskeletal diseases is, to a large extent, derived from preclinical and basic research experiments. In vivo molecular imaging enables us to study molecular targets and to measure biochemical processes non-invasively and longitudinally, providing information on disease processes and potential therapeutic strategies, e.g. efficacy of novel therapeutic interventions, which is of complementary value next to ex vivo (post mortem) histopathological analysis and molecular assays. Remarkably, the large body of preclinical imaging studies in inflammatory musculoskeletal disease is in contrast with the limited reports on molecular imaging in clinical practice and clinical guidelines. Therefore, in this EANM-endorsed position paper, we performed a systematic review of the preclinical studies in inflammatory musculoskeletal diseases that involve radionuclide imaging, with a detailed description of the animal models used. From these reflections, we provide recommendations on what future studies in this field should encompass to facilitate a greater impact of radionuclide imaging techniques on the translation to clinical settings. Show less
Molecular imaging is one of the pillars of precision surgery. Its applications range from early diagnostics to therapy planning, execution, and the accurate assessment of outcomes. In particular,... Show moreMolecular imaging is one of the pillars of precision surgery. Its applications range from early diagnostics to therapy planning, execution, and the accurate assessment of outcomes. In particular, molecular imaging solutions are in high demand in minimally invasive surgical strategies, such as the substantially increasing field of robotic surgery. This review aims at connecting the molecular imaging and nuclear medicine community to the rapidly expanding armory of surgical medical devices. Such devices entail technologies ranging from artificial intelligence and computer-aided visualization technologies (software) to innovative molecular imaging modalities and surgical navigation (hardware). We discuss technologies based on their role at different steps of the surgical workflow, i.e., from surgical decision and planning, over to target localization and excision guidance, all the way to (back table) surgical verification. This provides a glimpse of how innovations from the technology fields can realize an exciting future for the molecular imaging and surgery communities. Show less
Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of... Show moreWithin interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery. Show less
Background: Approximately 15% of patients undergoing resection for presumed perihilar cholangiocarcinoma (PHC) have benign disease at final pathological assessment. Molecular imaging targeting... Show moreBackground: Approximately 15% of patients undergoing resection for presumed perihilar cholangiocarcinoma (PHC) have benign disease at final pathological assessment. Molecular imaging targeting tumor-specific biomarkers could serve as a novel diagnostic tool to reduce these futile surgeries. Imaging agents have been developed, selectively binding integrin alpha(nu)beta 6, a cell receptor upregulated in pancreatobiliary malignancies, for both (preoperative) PET and (intraoperative) fluorescent imaging. Here, expression of integrin alpha(nu)beta 6 is evaluated in PHC, intrahepatic cholangiocarcinoma (ICC), hepatocellular carcinoma (HCC) and benign disease mimicking PHC using immunohistochemistry.Materials & methods: Three tissue microarrays (TMA) including 103 PHC tumor cores and sixty tissue samples were selected from resection specimens of pathologically proven PHC (n = 20), ICC (n = 10), HCC (n = 10), metastatic PHC lymph nodes (n = 10) and benign disease (presumed PHC with benign disease at pathological assessment, n = 10). These samples were stained for integrin anb6 and quantified using the H-score.Results: Immunohistochemical staining for integrin alpha(nu)beta 6 showed membranous expression in all twenty PHC whole mount slides (100%) and 93 out of 103 (92%) PHC tumor cores. Mean H-score of PHC samples was 195 +/- 71, compared to a mean H-score of 126 +/- 57 in benign samples (p = 0.013). In both benign and PHC samples, inflammatory infiltrates and pre-existent peribiliary glands showed integrin anb6 expression. The mean H-score across ten ICC was 33 +/- 53, which was significantly lower compared to PHC (p < 0.001) but too weak to consistently discriminate ICC from HCC (H-score 0)(p = 0.062).Conclusion: Integrin anb6 is abundantly expressed in PHC and associated metastatic lymph nodes. Expression is significantly higher in PHC as compared to benign disease mimicking PHC, ICC and HCC, emphasizing its potential as a target for tumor-specific molecular imaging. (C) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/ Show less
Debie, P.; Lafont, C.; Defrise, M.; Hansen, I.; Willigen, D.M. van; Leeuwen, F.W.B. van; ... ; Hernot, S. 2020
A compound's intratumoural distribution is an important determinant for the effectiveness of molecular therapy or imaging. Antibodies (Abs), though often used in the design of targeted compounds,... Show moreA compound's intratumoural distribution is an important determinant for the effectiveness of molecular therapy or imaging. Antibodies (Abs), though often used in the design of targeted compounds, struggle to achieve a homogenous distribution due to their large size and bivalent binding mechanism. In contrast, smaller compounds like nanobodies (Nbs) are expected to distribute more homogenously, though this has yet to be demonstrated in vivo at the microscopic level. We propose an intravital approach to evaluate the intratumoural distribution of different fluorescently labeled monomeric and dimeric Nb tracers and compare this with a monoclonal antibody (mAb).Monomeric and dimeric formats of the anti-HER2 (2Rb17c and 2Rb17c-2Rb17c) and control (R3B23 and R3B23-R3B23) Nb, as well as the dimeric monovalent Nb 2Rbl7c-R3B23 were generated and fluorescently labeled with a Cy5 fluorophore. The mAb trastuzumab-Cy5 was also prepared. Whole-body biodistribution of all constructs was investigated in mice bearing subcutaneous xenografts (HER2 + SKOV3) using in vivo epi-fluorescence imaging. Next, for intravital experiments, GFP-expressing SKOV3 cells were grown under dorsal window chambers on athymic nude mice (n = 3/group), and imaged under a fluorescence stereo microscope immediately after intravenous injection of the tracers. Consecutive fluorescence images within the tumour were acquired over the initial 20 min after injection and later, single images were taken at 1, 3 and 24 h post-injection. Additionally, two-photon microscopy was used to investigate the colocalization of GFP (tumour cells) and Cy5 fluorescence (tracers) at higher resolution.Whole-body images showed rapid renal clearance of all Nbs, and fast tumour targeting for the specific Nbs. Specific tumour uptake of the mAb could only be clearly distinguished from background after several hours. Intravital imaging revealed that monomeric Nb tracers accumulated rapidly and distributed homogenously in the tumour mere minutes after intravenous injection. The dimeric compounds initially achieved lower fluorescence intensities than the monomeric. Furthermore, whereas the HER2-specific dimeric bivalent compound remained closely associated to the blood vessels over 24 h, the HER2-specific dimeric monovalent tracer achieved a more homogenous tumour distribution from 1 h post-injection onwards. Non-specific tracers were not retained in the tumour. Trastuzumab had the most heterogenous intratumoural distribution of all evaluated compounds, while -due to the long blood retention- achieving the highest overall tumour uptake at 24 h post-injection.In conclusion, monomeric Nbs very quickly and homogenously distribute through tumour tissue, at a rate significantly greater than dimeric Nbs and mAbs. This underlines the potential of monomeric Nb tracers and therapeutics in molecular imaging and targeted therapies. Show less
Purpose: To assess the feasibility of using freehand Single Photon Emission Computed Tomography (free-handSPECT) for the identification of technetium-99m-hydroxydiphosphonate (Tc-99m-HDP) positive... Show morePurpose: To assess the feasibility of using freehand Single Photon Emission Computed Tomography (free-handSPECT) for the identification of technetium-99m-hydroxydiphosphonate (Tc-99m-HDP) positive bone lesions and to evaluate the possibility of using these imaging data-sets for augmented- and virtual-reality based navigation approaches.Material and methods: In 20 consecutive patients referred for scintigraphy with Tc-99m-HDP, 21 three-dimensional freehandSPECT-images were generated using a handheld gamma camera. Concordance of the two different data sets was ranked. Furthermore, feasibility of segmenting the hotspot of tracer accumulation for navigation purposes was assessed.Results: In 86% of the cases freehandSPECT images showed good concordance with the corresponding part of the scintigraphic images. In lesions with a signal to background ratio (SBR) > 1.36, freehandSPECT provided an automatically segmented reference point for navigation purposes. In 14% of the cases (average SBR 1.82, range 1.0-3.4) freehandSPECT images showed intermediate concordance due to difficult anatomical area or negative bone scintigraphy and could not be used as navigation targets.Conclusion: In this pilot study, in 86% of the cases freehandSPECT demonstrated good concordance with traditional scintigraphy. A lesion with a SBR of 1.36 or more was suitable for navigation. These high quality freehandSPECT images supported the future exploration navigation strategies, e.g. guided needle biopsies. (C) 2019 Sociedad Espaiiola de Medicina Nuclear e Imagen Molecular. Published by Elsevier Espatia, S.L.U. All rights reserved. Show less
Background Bacterial infections are still a major global healthcare problem. To combat the increasing antimicrobial resistance, early diagnosis of bacterial infection-including the identification... Show moreBackground Bacterial infections are still a major global healthcare problem. To combat the increasing antimicrobial resistance, early diagnosis of bacterial infection-including the identification of bacterial specie-is needed to improve antibiotic stewardship and to help reduce the use of broad-spectrum antibiotics. To aid successful targeted antibiotic treatment, specific detection and localisation of infectious organisms is warranted. Nuclear medicine imaging approaches have been successfully used to diagnose bacterial infections and to differentiate between pathogen induced infections and sterile inflammatory processes.Aim In this comprehensive review we present an overview of recent developments in radiolabelled bacterial imaging tracers.Methods The PubMed/MEDLINE and Embase (OvidSP) literature databases were systematically searched for publications on SPECT and PET on specific imaging of bacterial using specific guidelines with MeSH-terms, truncations, and completion using cross-references. Tracers in literature that was extensively reviewed before 2016 were not included in this update. Where possible, the chemical structure of the radiolabelled compounds and clinical images were shown.Results In 219 original articles pre-clinical and clinical imaging of bacterial infection with new tracers were included. In our view, the highest translational potential lies with tracers that are specific to target the pathogens: e.g., Tc-99m- and Ga-68-labelled UBI29-41, Tc-99m-vancomycin, m-[F-18]-fluoro-PABA, [methyl-C-11]-D-methionine, [F-18]-FDS, [F-18]-maltohexaose and [F-18]-maltotriose. An encouraging note is that some of these tracers have already been successfully evaluated in clinical settings.Conclusion This review summarises updates in tracer development for specific (pre-clinical and clinical) imaging of bacterial infections. We propsed some promising tracers that are likely to become innovative standards in the clinical setting in the near feature. Show less
PurposeNear-infrared spectroscopy (NIRS) has recently been proposed as an indirect technique to assess brown adipose tissue (BAT) in young men. NIRS arises as a novel technique to avoid the... Show morePurposeNear-infrared spectroscopy (NIRS) has recently been proposed as an indirect technique to assess brown adipose tissue (BAT) in young men. NIRS arises as a novel technique to avoid the limitations of the gold-standard 2-deoxy-2-[F-18]fluoro-D-glucose ([F-18]DG) positron emission tomography combined with X-ray computed tomography (PET/CT). The aim of this study was to examine the association between near-infrared spatially resolved spectroscopy (NIRSRS) parameters and BAT volume and activity estimated by [F-18]DG-PET/CT in 18 young healthy women.ProceduresNIR(SRS) parameters [tissue saturation index and concentrations of total haemoglobin, oxy-haemoglobin, and deoxy-haemoglobin] were continuously measured in the supraclavicular and forearm regions, in both warm and cold (2h of personalised cold exposure) conditions. Then, the NIRSRS data were analysed as an average of 5min in 4 different periods: (i) warm period as the baseline record, (ii) cold period I, (iii) cold period II, and (iv) cold period III. The data were then correlated with BAT volume and activity (SUVmean and SUVpeak) estimated by [F-18]DG-PET/CT.ResultsThere was no association between the NIRSRS parameters in the supraclavicular region in warm conditions (no previous cold exposure) and BAT volume and activity (P>0.05). Similarly, the cold-induced changes of the NIRSRS parameters in the supraclavicular region were not associated with BAT volume and activity (P>0.05).ConclusionsNIR(SRS) does not seem to be a valid technique to indirectly assess BAT in young healthy women. Further research is needed to validate this technique against other methods such as PET/CT using different radiotracers or magnetic resonance imaging. Show less
