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Immunotherapies, especially checkpoint inhibitors such as anti-programmed cell death protein 1 (anti-PD-1) antibodies, have transformed cancer treatment by enhancing the immune systems capability to target and kill cancer cells. However, predicting immunotherapy response remains challenging. 18F-arabinosyl guanine ([18F]F-AraG) is a molecular imaging tracer targeting activated T cells, which may facilitate therapy response assessment by noninvasive quantification of immune cell activity within the tumor microenvironment and elsewhere in the body. The aim of this study was to obtain preliminary data on total-body pharmacokinetics of [18F]F-AraG as a potential quantitative biomarker for immune response evaluation. Methods: The study consisted of 90-min total-body dynamic scans of 4 healthy subjects and 1 non-small cell lung cancer patient who was scanned before and after anti-PD-1 immunotherapy. Compartmental modeling with Akaike information criterion model selection was used to analyze tracer kinetics in various organs. Additionally, 7 subregions of the primary lung tumor and 4 mediastinal lymph nodes were analyzed. Practical identifiability analysis was performed to assess the reliability of kinetic parameter estimation. Correlations of the SUVmean, the tissue-to-blood SUV ratio (SUVR), and the Logan plot slope (K Logan) with the total volume of distribution (V T) were calculated to identify potential surrogates for kinetic modeling. Results: Strong correlations were observed between K Logan and SUVR with V T, suggesting that they can be used as promising surrogates for V T, especially in organs with a low blood-volume fraction. Moreover, practical identifiability analysis suggested that dynamic [18F]F-AraG PET scans could potentially be shortened to 60 min, while maintaining quantification accuracy for all organs of interest. The study suggests that although [18F]F-AraG SUV images can provide insights on immune cell distribution, kinetic modeling or graphical analysis methods may be required for accurate quantification of immune response after therapy. Although SUVmean showed variable changes in different subregions of the tumor after therapy, the SUVR, K Logan, and V T showed consistent increasing trends in all analyzed subregions of the tumor with high practical identifiability. Conclusion: Our findings highlight the promise of [18F]F-AraG dynamic imaging as a noninvasive biomarker for quantifying the immune response to immunotherapy in cancer patients. Promising total-body kinetic modeling results also suggest potentially wider applications of the tracer in investigating the role of T cells in the immunopathogenesis of diseases.

In vivo molecular imaging tools are crucially important for elucidating how cells move through complex biological systems; however, achieving single-cell sensitivity over the entire body remains challenging. Here, we report a highly sensitive and multiplexed approach for tracking upward of 20 single cells simultaneously in the same subject using positron emission tomography (PET). The method relies on a statistical tracking algorithm (PEPT-EM) to achieve a sensitivity of 4 becquerel per cell and a streamlined workflow to reliably label single cells with over 50 becquerel per cell of 18F-fluorodeoxyglucose (FDG). To demonstrate the potential of the method, we tracked the fate of more than 70 melanoma cells after intracardiac injection and found they primarily arrested in the small capillaries of the pulmonary, musculoskeletal, and digestive organ systems. This study bolsters the evolving potential of PET in offering unmatched insights into the earliest phases of cell trafficking in physiological and pathological processes and in cell-based therapies.

Dynamic PET allows quantification of physiological parameters through tracer kinetic modeling. For dynamic imaging of brain or head and neck cancer on conventional PET scanners with a short axial field of view, the image-derived input function (ID-IF) from intracranial blood vessels such as the carotid artery (CA) suffers from severe partial volume effects. Alternatively, optimization-derived input function (OD-IF) by the simultaneous estimation (SIME) method does not rely on an ID-IF but derives the input function directly from the data. However, the optimization problem is often highly ill-posed. We proposed a new method that combines the ideas of OD-IF and ID-IF together through a kernel framework. While evaluation of such a method is challenging in human subjects, we used the uEXPLORER total-body PET system that covers major blood pools to provide a reference for validation.MethodsThe conventional SIME approach estimates an input function using a joint estimation together with kinetic parameters by fitting time activity curves from multiple regions of interests (ROIs). The input function is commonly parameterized with a highly nonlinear model which is difficult to estimate. The proposed kernel SIME method exploits the CA ID-IF as a priori information via a kernel representation to stabilize the SIME approach. The unknown parameters are linear and thus easier to estimate. The proposed method was evaluated using 18F-fluorodeoxyglucose studies with both computer simulations and 20 human-subject scans acquired on the uEXPLORER scanner. The effect of the number of ROIs on kernel SIME was also explored.ResultsThe estimated OD-IF by kernel SIME showed a good match with the reference input function and provided more accurate estimation of kinetic parameters for both simulation and human-subject data. The kernel SIME led to the highest correlation coefficient (R = 0.97) and the lowest mean absolute error (MAE = 10.5 %) compared to using the CA ID-IF (R = 0.86, MAE = 108.2 %) and conventional SIME (R = 0.57, MAE = 78.7 %) in the human-subject evaluation. Adding more ROIs improved the overall performance of the kernel SIME method.ConclusionThe proposed kernel SIME method shows promise to provide an accurate estimation of the blood input function and kinetic parameters for brain PET parametric imaging.

The lungs are supplied by both the pulmonary arteries carrying deoxygenated blood originating from the right ventricle and the bronchial arteries carrying oxygenated blood downstream from the left ventricle. However, this effect of dual blood supply has never been investigated using PET, partially because the temporal resolution of conventional dynamic PET scans is limited. The advent of PET scanners with a long axial field of view, such as the uEXPLORER total-body PET/CT system, permits dynamic imaging with high temporal resolution (HTR). In this work, we modeled the dual-blood input function (DBIF) and studied its impact on the kinetic quantification of normal lung tissue and lung tumors using HTR dynamic PET imaging. Methods: Thirteen healthy subjects and 6 cancer subjects with lung tumors underwent a dynamic 18F-FDG scan with the uEXPLORER for 1 h. Data were reconstructed into dynamic frames of 1 s in the early phase. Regional time-activity curves of lung tissue and tumors were analyzed using a 2-tissue compartmental model with 3 different input functions: the right ventricle input function, left ventricle input function, and proposed DBIF, all with time delay and dispersion corrections. These models were compared for time-activity curve fitting quality using the corrected Akaike information criterion and for differentiating lung tumors from lung tissue using the Mann-Whitney U test. Voxelwise multiparametric images by the DBIF model were further generated to verify the regional kinetic analysis. Results: The effect of dual blood supply was pronounced in the high-temporal-resolution time-activity curves of lung tumors. The DBIF model achieved better time-activity curve fitting than the other 2 single-input models according to the corrected Akaike information criterion. The estimated fraction of left ventricle input was low in normal lung tissue of healthy subjects but much higher in lung tumors (∼0.04 vs. ∼0.3, P < 0.0003). The DBIF model also showed better robustness in the difference in 18F-FDG net influx rate [Formula: see text] and delivery rate [Formula: see text] between lung tumors and normal lung tissue. Multiparametric imaging with the DBIF model further confirmed the differences in tracer kinetics between normal lung tissue and lung tumors. Conclusion: The effect of dual blood supply in the lungs was demonstrated using HTR dynamic imaging and compartmental modeling with the proposed DBIF model. The effect was small in lung tissue but nonnegligible in lung tumors. HTR dynamic imaging with total-body PET can offer a sensitive tool for investigating lung diseases.

Objectives: To determine the feasibility and diagnostic accuracy of fast whole-body magnetic resonance imaging (WB-MRI) compared to whole-body computed tomography (WB-CT) in detecting injuries of slightly to moderately injured trauma patients. Materials and methods: In a prospective single-center approach, trauma patients from convenience sampling with an expected Abbreviated Injury Scale (AIS) score ≤ 3 at admission, received an indicated contrast-enhanced WB-CT (reference standard) and a plain WB-MRI (index test) voluntarily up to five days after trauma. Two radiologists, blinded to the WB-CT findings, evaluated the absence or presence of injuries with WB-MRI in four body regions: head, torso, axial skeleton, and upper extremity. Diagnostic accuracy was determined using sensitivity, specificity, positive predictive value, and negative predictive value by body region. Results: Between June 2019 and July 2021, 40 patients were assessed for eligibility of whom 35 (median age (interquartile range): 50 (32.5) years; 26 men) received WB-MRI. Of 140 body regions (35 patients × 4 regions), 31 true positive, 6 false positive, 94 true negative, and 9 false negative findings were documented with WB-MRI. Thus, plain WB-MRI achieved a total sensitivity of 77.5% (95%-confidence interval (CI): (61.6–89.2%)), specificity of 94% (95%-CI: (87.4–97.8%)), and diagnostic accuracy of 89.3% (95%-CI: (82.9–93.9%)). Across the four regions sensitivity and specificity varied: head (66.7%/93.1%), torso (62.5%/96.3%), axial skeleton (91.3%/75%), upper extremity (33.3%/100%). Both radiologists showed substantial agreement on the WB-MRI reading (Cohen's Kappa: 0.66, 95%-CI: (0.51–0.81)). Conclusion: Regarding injury detection, WB-MRI is feasible in slightly to moderately injured trauma patients, especially in the axial skeleton. Clinical relevance statement: Besides offering a radiation-free approach, whole-body MRI detects injuries almost identically to whole-body CT in slightly to moderately injured trauma patients, who comprise a relevant share of all trauma patients. Key Points: Whole-body MRI could offer radiation-free injury detection in slightly to moderately injured trauma patients. Whole-body MRI detected injuries almost identically compared to whole-body CT in this population. Whole-body MRI could be a radiation-free approach for slightly to moderately injured young trauma patients. [ABSTRACT FROM AUTHOR]

Background: The authors assessed the feasibility, acceptability, and impact on cancer worry of a cancer screening program using multicancer early detection (MCED) tests and whole‐body magnetic resonance imaging (WBM) in individuals at high cancer risk because of family history or germline variants in cancer‐susceptibility genes. Methods: This prospective trial enrolled participants aged 50 years and older who had a significant family history of cancer or a cancer‐susceptibility gene variant. Participants underwent noncontrast WBM and MCED testing. The results were shared with participants, and further imaging or consultations were conducted as needed. Surveys assessing anxiety, cancer worry, and acceptability of the intervention were completed at baseline and 6 months after testing. Results: One hundred participants were enrolled: 98 completed both WBM and MCED testing, and 89 completed their 6‐month follow‐up. The median age of participants was 62 years (range, 51–83 years), and 64% were women. Four participants (4%) were diagnosed with cancer based on WBM findings and subsequent work‐up, and all four underwent surgical resection. Two intraductal papillary mucinous neoplasms of the pancreas were detected and are being monitored. MCED testing was positive in four participants, none of whom had suspicious findings on magnetic resonance imaging. One participant with a JAK2 mutation and thrombocytosis is under monitoring for potential hematologic malignancy. Sixty‐two participants (85%) somewhat/strongly agreed that study participation reduced cancer worry. Composite Cancer Worry Scale scores demonstrated decreased worry at 6 months compared with baseline (51% vs. high worry in 69%; p <.001). Conclusions: MCED and WBM testing were feasible, acceptable, and were associated with decreased cancer worry at 6 months (clinical trials registration: NCT05868486). In this trial of whole‐body magnetic resonance imaging (WBM) and multicancer early detection (MCED) testing in people with a strong family history of cancer, WBM and MCED testing were feasible, acceptable, and led to reduced worry about cancer. Cancer screening with WBM and MCED testing may reduce cancer worry in high‐risk individuals. [ABSTRACT FROM AUTHOR]

The aim was to evaluate the performance of the Peritoneal Cancer Index (PCI) using imaging (ultrasound, contrast-enhanced computed tomography (CT), and whole-body diffusion-weighted magnetic resonance imaging (WB-DWI/MRI) in assessing peritoneal carcinomatosis and predicting non-resectability in tubo-ovarian carcinoma patients. This was a prospective multicenter observational study. We considered all patients with suspected primary ovarian/tubal/peritoneal cancer who underwent preoperative ultrasound, CT, and WB-DWI/MRI (if available). The optimal cut off value for assessing the performance of the methods in predicting non-resectability was identified at the point at which the sensitivity and specificity were most similar. The reference standard to predict non-resectability was surgical outcome in terms of residual disease >1 cm or surgery not feasible. Agreement between imaging methods and surgical exploration in assessing sites included in the PCI score was evaluated using the Intraclass Correlation Coefficient (ICC). 242 patients were included from January 2020 until November 2022. The optimal PCI cut-off for predicting non-resectability for surgical exploration was >12, which achieved the best AUC of 0.87, followed by ultrasound with a cut-off of >10 and AUC of 0.81, WB-DWI/MRI with a cut-off of >12 and AUC of 0.81, and CT with a cut-off of >11 and AUC of 0.74. Using ICC, ultrasound had very high agreement (0.94) with surgical PCI, while CT and WB-DWI/MRI had high agreement (0.86 and 0.87, respectively). Ultrasound performed by an expert operator had the best agreement with surgical findings compared to WB-DWI/MRI and CT in assessing radiological PCI. In predicting non-resectability, ultrasound was non-inferior to CT, while its non-inferiority to WB-DWI/MRI was not demonstrated. [Display omitted] • This is the largest prospective study assessing the performance of ultrasound, CT and MRI to predict non-resectability in tubo-ovarian carcinoma. • Surgical exploration using PCI cut-off >12 was the best method for predicting non-resectability. • Ultrasound was non-inferior to CT, while non-inferiority of ultrasound to MRI was not demonstrated. [ABSTRACT FROM AUTHOR]

Introduction: Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome primarily caused by germline TP53 pathogenic/likely pathogenic (P/LP) variants. Soft tissue and bone sarcomas are among the most frequently occurring of the many LFS-associated cancer types. Cancer screening recommendations for LFS are centered around annual whole-body MRI (wbMRI), the interpretation of which can be challenging. This study aims to characterize sarcoma topography in LFS. Methods: Study subjects included individuals from clinically and genetically ascertained cohorts of germline TP53 variant-carriers, namely the National Cancer Institute's LFS longitudinal cohort study (NCI-LFS), the NCI Genetic Epidemiology of Osteosarcoma (NCI-GEO) study, and the germline TP53 Database. Results: Data was aggregated for a total of 160 sarcomas that had detailed topography available. Abdominal sarcomas and extremity osteosarcomas were among the most frequent locations of sarcomas. Chi-squared analyses showed no statistical differences in sarcoma topography based on age (pediatric vs adult) or sex (male vs female). A case series of sarcomas from the NCI-LFS study highlights the diagnostic challenges due to topography-related imaging. Discussion: While LFS-related sarcomas frequently occur in expected locations such as the extremities, they also occur in less typical sites, leading to difficulties in discerning between differential diagnoses on wbMRI and imaging. Prospective collection of detailed cancer topography in individuals with LFS will further aid in recommendations for radiologic interpretation and personalized screening in individuals with LFS. [ABSTRACT FROM AUTHOR]

We present here a user-friendly calculator for the setting of a pediatric split-bolus polytrauma computed tomography (CT) protocol with a mixed arterial and venous phase, aiming to both reduce radiation dose and improve workflow while assuring optimal image quality. All the different parameters are calculated based on patient's weight with rapid computation of the injected contrast media and saline volumes, injection's flow rate, injection's timing, and optimal acquisition time. The designed calculator is built in a widely available Google Sheets file, accessible by a quick response (QR) code. Although polytrauma imaging represents the main goal of the technique, it can be used in a wide variety of contexts, including oncological, infectious, and vascular pathologies. [ABSTRACT FROM AUTHOR]

Background: There is limited research on body composition in persons with haemophilia (PwH). The literature describes an increased body fat distribution and decreased lean mass in PwH compared to healthy controls using bioimpedance analysis. Using dual x‐ray absorptiometry (DXA), which is known to be the most accurate method, this investigation aims to postulate reference data for body composition parameters within haemophilia severity phenotypes and age groups. Methods: Persons underwent whole body DXA screening using Horizon. Body fat percentage, estimated visceral adipose tissue (VAT), appendicular fat and lean mass, and lean and fat mass in relation to body height were assessed. Haemophilia severity and five age groups were distinguished. Results: Two hundred and one persons with mild (n = 44), moderate (n = 41), or severe (n = 116) haemophilia A/B (median age 40 [28–55; 1.IQ–3.IQ] years) were analysed. The median body fat percentage was 28.7% [25.5%–33.9%] and median estimated VAT was 657 g [403–954 g] with no significant difference between severity phenotypes (p =.474; p =.781). Persons with severe haemophilia had less lean mass compared to moderate and mild haemophilia (p =.013; p =.034). Total and appendicular fat is increased in older PwH (aged ≥40 years) compared to younger PwH (aged ≤29 years; p <.05). Lean mass did not differ between age groups. Conclusion: This study provides valuable reference data for body composition parameters in PwH. Persons with severe haemophilia show significantly less lean mass compared to persons with moderate or mild haemophilia. Body fat percentage and VAT did not differ between severity phenotypes, but increased with age. [ABSTRACT FROM AUTHOR]

Metastasis of World Health Organization (WHO) grade II or grade II meningiomas are rare. The aim of this study was to investigate their incidence, associated risk factors, and treatment course. Patients with surgically resected WHO grade II or grade III meningiomas were reviewed based on histopathology with the 2016 WHO criteria. Metastasis was diagnosed through whole body image scan followed by surgical resection or biopsy. Clinical factors were analyzed for their association with metastasis. Among the 131 enrolled patients, metastasis was diagnosed after tumor relapse in 7 (incidence rate 3.6%) at a mean 30.9 months after the initial surgery. The metastasis after tumor relapse group had the worst overall survival, followed by tumor relapse without metastasis and nonrelapse groups (P < 0.001). The independent factors associated with metastasis were major vessel compromise by primary tumors (hazard ratio [HR] = 9.9, P = 0.035), tumor relapse time less than 24 months (HR = 7.0, P = 0.036), and subtotal resection without adjuvant radiotherapy to the primary tumor (HR = 3.5, P = 0.047). Neither grading nor histochemical staining was significantly associated with metastasis, whereas higher vascularity seemed to be more common in metastatic lesions than primary tumors. The presence of metastasis contributed to poor outcomes and was related to earlier tumor relapse and major vessel compromise. Subtotal resection should be followed by adjuvant radiotherapy to reduce the risk of metastasis. Further research is warranted to identify circulating or pathologic biomarkers for the early detection of metastasis. [ABSTRACT FROM AUTHOR]

The article discusses the development of a low-cost, computing-powered whole-body MRI scanner operating at 0.05 Tesla, aiming to improve MRI accessibility in healthcare. The scanner utilizes deep learning techniques for image reconstruction, enhancing image quality and providing a more affordable option compared to high-field MRI scanners. The technology offers advantages such as open scanning environment, less noise, and improved patient comfort, with potential applications in cancer detection and other medical fields. Future research is needed to further advance ULF MRI technology and evaluate its clinical efficacy in various healthcare settings. [Extracted from the article]

Background: Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) poses clinical challenges due to its heterogeneous ocular and systemic manifestations. We aim to report the systemic involvement and the clinical, serological and radiological associations of a cohort of Chinese patients. Methods: A territory-wide, biopsy-proven, Chinese cohort. A retrospective, masked chart review of medical records, orbital images, and histopathology reports. Results: A total of 122 (65 male) patients with a follow-up of 81 ± 49 (24 to 84) months were reviewed. Ninety (74%) patients presented bilaterally. Subacute upper eyelid swelling was the commonest presentation (82/122, 67%). During follow-up, 91/122 patients (75%) underwent extra-orbital imaging including computer tomography (692 films), ultrasonography (182 films), magnetic resonance imaging (76 films) and whole body FDG-PET scan (33 films). Eighty-six (95%) of these 91 patients had extra-orbital involvement radiologically (2.7 ± 1.6 regions, range: 0 to 9). Lymph node was the most prevalent (N = 60,66%), followed by salivary gland (N = 51,56%), lung (N = 49,54%), kidney (N = 22, 24%), hepatobiliary tree (N = 18, 20%) and pancreas (N = 17, 19%). Other organs include thyroid, aorta, meninges/brain and skin. Twenty-eight (23%) patients had allergic diseases (19 asthma, 16 allergic rhinitis, and 6 eczemas). Fifty-seven (48%) patients had paranasal sinusitis. Serum eosinophilia was associated with a higher number (3.24 versus 2.52, P = 0.0304) of organ involvement. Patients with deep organ involvement was associated with a higher age of IgG4-ROD onset (70 ± 12 versus 56 ± 13, P < 0.0001). Conclusions: 95% of the patients who underwent systemic imaging in our cohort had systemic organ involvement. An early physicians' assessment and radiological imaging are recommended after the diagnosis of IgG4-ROD. [ABSTRACT FROM AUTHOR]

Introduction. Well-differentiated thyroid cancer (DTC) is curable in most patients with adequate surgical approach, radioactive iodine (RAI) treatment, and thyroid-stimulating hormone (TSH) suppression. However, around 2%-4% of cases experience a local recurrence in lateral cervical lymph nodes during a follow-up. Among these cases, nearly two-thirds become resistant to RAI therapy, known as RAIrefractory DTC (RR-DTC), offering poor prognosis and limited therapeutic options. We present the case of erroneously suspected RAI-refractory DTC due to incidental finding of coexisting cervical ganglioneuroma. Case report. A 44-year-old man was administered the second radioiodine dose in our department due to the existence of locoregional metastatic lymph nodes of papillary thyroid carcinoma (PTC). During the follow up, raising tendency of suppressed serum thyroglobulin levels, negative control diagnostic 131I whole body scan, and negative 18F-fluorodeoxyglucose (FDG)-positron emission tomography scan (PET) aroused suspicion of RR-DTC. Although the patient was considered for peptide-receptor radionuclide therapy (PRRT) optionally, mainly because of positive finding in patient's neck on 99mTc-Hynic-TOC imaging (tektrotyd scan), the preference was given to a surgical approach. Finally, histopathological examination of extirpated neck tumor mass confirmed the presence of one lymph node metastasis of papillary carcinoma and coexistence of ganglioneuroma. Conclusion. The authors want to point out the importance of multidisciplinary approach in diagnostics and therapy in case of suspected loss of thyroid differentiation features, as well as clinical awareness of coexisting asymptomatic rare tumors. [ABSTRACT FROM AUTHOR]

This paper attempts to theoretically reconsider body image development in infants from a phenomenological viewpoint of the body. Because body image is defined as the mental picture of one's whole body, our main question is how we obtain the perspective to view our own body as a whole in constituting body image. First, focusing on the development of mirror self‐cognition in the first 2 years of life, we find that this perspective derives from that of others in embodied interactions with infants. We then trace the process whereby others' perspectives appear in dyadic interactions between infants and caregivers. Since joint attention is established around 9 months, this dyadic interaction is transformed into a triadic relationship between the infant, caregiver, and object, which is experienced as "secondary intersubjectivity." Infant body image is constituted gradually within this intersubjective context. Based on phenomenological descriptions, we propose that the hands are the first organ and the face the last organ to be incorporated into one's body image. We conclude that the constitution of body image is not merely a sensory task of integrating proprioceptive and visual images of the body, but a social task of internalizing others' perspectives regarding one's own body. [ABSTRACT FROM AUTHOR]

Objective: To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)–related spinal bone metastases. Materials and methods: Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported. Results: Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03). Conclusions: [68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate. Clinical relevance statement: In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001). Key Points: • Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma. [ABSTRACT FROM AUTHOR]

BackgroundSingle photon emission computed tomography (SPECT) is an imaging modality that has demonstrated its utility in a number of clinical indications. Despite this progress, a high sensitivity, high spatial resolution, multi-tracer SPECT with a large field of view suitable for whole-body imaging of a broad range of radiotracers for theranostics is not available.PurposeWith the goal of filling this technological gap, we have designed a cadmium zinc telluride (CZT) full-ring SPECT scanner instrumented with a broad-energy tungsten collimator. The final purpose is to provide a multi-tracer solution for brain and whole-body imaging. Our static SPECT does not rely on the dual- and the triple-head rotational SPECT standard paradigm, enabling a larger effective area in each scan to increase the sensitivity. We provide a demonstration of the performance of our design using a realistic model of our detector with simulated body-sized phantoms filled with 99m Tc and 177 Lu.MethodsWe create a realistic model of our detector by using a combination of a Geant4 Application for Tomographic Emission (GATE) Monte Carlo simulation and a finite element model for the CZT response, accounting for low-energy tail effects in CZT that affects the sensitivity and the scatter correction. We implement a modified dual-energy-window scatter correction adapted for CZT. Other corrections for attenuation, detector and collimator response, and detector gaps and edges are also included. The images are reconstructed using the maximum-likelihood expectation-maximization. Detector and reconstruction performance are characterized with point sources, Derenzo phantoms, and a body-sized National Electrical Manufacturers Association (NEMA) Image Quality (IQ) phantom for both 99m Tc and 177 Lu.ResultsOur SPECT design can resolve 7.9 mm rods for 99m Tc (140 keV) and 9.5 mm for 177 Lu (208 keV) in a hot-rod Derenzo phantom with a 3-min exposure and reach an image contrast of 78% for 99m Tc and 57% for 177 Lu using the NEMA IQ phantom with a 6-min exposure. Our modified scatter correction shows an improved contrast-recovery ratio compared to a standard correction.ConclusionsIn this paper, we demonstrate the good performance of our design for whole-body imaging purposes. This adds to our previous demonstration of improved qualitative and quantitative 99m Tc imaging of brain perfusion and 123 I imaging of dopamine transport with respect to state-of-the-art NaI dual-head cameras. We show that our design provides similar IQ and contrast to the commercial full-ring SPECT VERITON for 99m Tc. Regarding 177 Lu imaging of the 208 keV emissions, our design provides similar contrast to that of other state-of-the-art SPECTs with a significant reduction in exposure. The high sensitivity and extended energy range up to 250 keV makes our SPECT design a promising alternative for clinical imaging and theranostics of emerging radionuclides.

Background/Objectives: Disease recurrence and resistance to radioiodine (RAI) therapy are major challenges in the management of differentiated thyroid cancer (DTC). In particular, the TENIS (Thyroglobulin Elevated Negative Iodine Scintigraphy) syndrome, characterised by elevated thyroglobulin (Tg) serum levels in addition to a negative radioiodine whole body scan (WBS), complicates disease monitoring and treatment decisions. Conventional imaging techniques often fail to detect disease in WBS-negative patients with rising Tg levels, leading to limitations in therapeutic intervention. This systematic review and meta-analysis aims to evaluate the diagnostic accuracy of nuclear imaging modalities in detecting disease recurrence in patients with the TENIS syndrome and to provide insights to guide therapeutic approaches in this complex clinical scenario. Methods: A comprehensive search of PubMed/MEDLINE and EMBASE databases up to March 2024 was performed according to PRISMA guidelines. Eligible studies were selected, and quality assessment was performed with the QUADAS-2 tool. For each study, relevant data were extracted and synthesised. A meta-analysis of the diagnostic accuracy of [18F]FDG PET/CT was performed, and patient-based pooled sensitivity and specificity were calculated using a random-effects model. Statistical heterogeneity between studies was assessed using the I2 statistic. Results: Of the 538 studies initially identified, 22 were included in the systematic review, of which 18 were eligible for meta-analysis. The eligible studies, mainly focused on [18F]FDG PET/CT, showed variable sensitivity and specificity for the detection of RAI-refractory thyroid cancer lesions. For [18F]FDG PET/CT, pooled estimates displayed a sensitivity of 0.87 (95% CI: 0.82–0.90) and a specificity of 0.76 (95% CI: 0.61–0.86), with moderate heterogeneity between studies. Conclusions: [18F]FDG PET/CT remains central in the detection of disease recurrence in patients with the TENIS syndrome. The emergence of novel radiopharmaceuticals with specific molecular targets is a promising way to overcome the limitations of [18F]FDG in these patients and to open new theranostics perspectives. This review highlights the great potential of nuclear medicine in guiding therapeutic strategies for RAI-refractory thyroid cancer. [ABSTRACT FROM AUTHOR]

The article discusses the development and benefits of total body positron emission tomography (PET) scanners, which have an extended axial field of view and improved sensitivity compared to traditional scanners. These scanners allow for simultaneous imaging of the entire body, resulting in higher sensitivity, improved signal-to-noise ratio, shorter scan times, and the ability to conduct pediatric scans without anesthesia. The article highlights the clinical and research applications of total body PET scanners, including the quantification of mu-opioid receptors in the monkey brain, spinal cord, and peripheral organs. The study demonstrates the feasibility and advantages of using total body PET scanners for preclinical research. [Extracted from the article]

Simple Summary: Nuclear medicine imaging techniques consist of acquiring images after intravenous administration of a small dose of radioactive molecules. Different nuclear medicine techniques are available in the horse. Scintigraphy provides two-dimensional images and has been used for the detection of bone injuries in horses since the late 1970s. This was at the time the only alternative to radiographs to detect bone issues in horses. As other imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) have developed, the role of scintigraphy in horses has reduced. Scintigraphy remains, however, commonly used in racehorses to detect stress injuries and is also used in other horses to image larger body areas or even the whole body of a horse. In the last 10 years, positron emission tomography (PET) has become available in horses and provides higher resolution three-dimensional images. PET shows promising applications by either replacing the use of scintigraphy for the smaller areas of the limbs or by adding useful information to other imaging techniques. PET allows detection of some injuries prior to their identification with CT or MRI and also helps decide if an injury is active or represents an old scar. Scintigraphy and Positron Emission Tomography (PET) are both nuclear medicine imaging techniques, providing functional information of the imaged areas. Scintigraphy is a two-dimensional projected imaging technique that was introduced in equine imaging in the late 1970s. Scintigraphy allows imaging of large body parts and can cover multiple areas, remaining the only technique commonly used in horses for whole body imaging. PET is a cross-sectional imaging technique, first used in horses in 2015, allowing higher resolution three-dimensional functional imaging of the equine distal limb. This manuscript will cover current use and values of these two modalities in equine lameness diagnosis. [ABSTRACT FROM AUTHOR]

Acknowledging the increasing use of whole-body magnetic resonance imaging (WB-MRI) in the oncological setting, we conducted a narrative review focusing on practical aspects of the examination and providing a synthesis of various acquisition protocols described in the literature. Firstly, we addressed the topic of patient preparation, emphasizing methods to enhance examination acceptance. This included strategies for reducing anxiety and patient distress, improving staff–patient interactions, and increasing overall patient comfort. Secondly, we analysed WB-MRI acquisition protocols recommended in existing imaging guidelines, such as MET-RADS-P, MY-RADS, and ONCO-RADS, and provided an overview of acquisition protocols reported in the literature regarding other expanding applications of WB-MRI in oncology, in patients with breast cancer, ovarian cancer, melanoma, colorectal and lung cancer, lymphoma, and cancers of unknown primary. Finally, we suggested possible acquisition parameters for whole-body images across MR systems from three different vendors. [ABSTRACT FROM AUTHOR]

Objective: We aim to present the findings and effectiveness of Whole Body Magnetic Resonance Imaging (WBMRI), which we use in the Health Screening Program (HSP) to diagnose cancer in early stage. Methods: This retrospective study was conducted between January 2017-February 2023. 393 individuals, between the ages of 18 and 85, who underwent WBMRI for HSP purposes, were included. The mean age was 50. Results: Malignancy suspicious lesions were observed in the head/neck region in 25 cases. Additional Magnetic Resonance (MRI) and Ultrasound (US) were performed. Mediastinal pathology was observed in 23 cases, and non-mediastinal thoracic pathologies were detected in 15. Therefore thorax Computed Tomography (CT), mammography, and breast US were performed. Benign lesions were observed in the liver in 44 cases, and US was performed. Malignancy-suspicious lesions in the liver were observed in 4, and dynamic abdominal MRI was performed. Cholelithiasis was observed in 16, and confirmed by US. The most common renal findings were; cysts and pelvicalyceal ectasia. Adrenal adenoma was observed in 5 cases. Two of the females had suspicion of gynecological malignancy. Massive diffuse concentric wall thickening was observed in the sigmoid colon, and colonoscopy was performed on one male. Musculoskeletal benign lesions were detected in 99 cases, and malignancy-suspicious lesions were detected in 35. Additional examinations such as US, CT, MRI, PET-CT, scintigraphy, and colonoscopy were performed on 172 cases. Malignancy was detected in 11 cases (2.8%). Conclusion: WBMRI is a radiation-free, non-invasive, short-term examination method. WBMRI is beneficial in diagnosing early-stage cancer. [ABSTRACT FROM AUTHOR]

Background: Internal dosimetry in individual patients is essential for safe and effective radioligand therapy. Multiple time point imaging for accurate dosimetry is time consuming and hence can be demanding for nuclear medicine departments as well as patients. The objectives of this study were (1) to assess absorbed doses to organs at risk and tumor lesions for [177Lu]Lu-PSMA-I&T using whole body SPECT imaging and (2) to investigate possible simplified dosimetry protocols. Methods: This study included 16 patients each treated with 4 cycles of [177Lu]Lu-PSMA-I&T. They underwent quantitative whole body SPECT/CT imaging (3 bed positions) at four time points (TP) comprising 2 h, 24 h, 48 h and 72–168 h post-injection (p.i.). Full 3D dosimetry (reference method) was performed for all patients and dose cycles for organs at risk (kidneys, parotid glands and submandibular glands) and up to ten tumor lesions per patient (resulting in 90 lesions overall). The simplified dosimetry methods (SM) included (1) generating time activity curves for subsequent cycles using a single TP of imaging applying the kinetics of dose cycle 1, and for organs at risk also (2) simple extrapolation from dose cycle 1 and (3) from both, dose cycle 1 and 2. Results: Normalized absorbed doses were 0.71 ± 0.32 mGy/MBq, 0.28 ± 0.12 mGy/MBq and 0.22 ± 0.08 mGy/MBq for kidneys, parotid glands and submandibular glands, respectively. Tumor doses decreased from 3.86 ± 3.38 mGy/MBq in dose cycle 1 to 2.01 ± 2.65 mGy/MBq in dose cycle 4. Compared to the full dosimetry approach the SM 1 using single TP imaging at 48 h p.i. resulted in the most accurate and precise results for the organs at risk in terms of absorbed doses per cycle and total cumulated dose. For tumor lesions better results were achieved using the fourth TP (≥ 72 h p.i.). Conclusion: Simplification of safety dosimetry protocols is possible for [177Lu]Lu-PSMA-I&T therapy. If tumor dosimetry is of interest a later imaging TP (≥ 72 h p.i.) should be used/added to account for the slower kinetics of tumors compared to organs at risk. [ABSTRACT FROM AUTHOR]

The regulation of inflammatory responses and pulmonary disease during SARS-CoV-2 infection is incompletely understood. Here we examine the roles of the prototypic pro- and anti-inflammatory cytokines IFNγ and IL-10 using the rhesus macaque model of mild COVID-19. We find that IFNγ drives the development of 18fluorodeoxyglucose (FDG)-avid lesions in the lungs as measured by PET/CT imaging but is not required for suppression of viral replication. In contrast, IL-10 limits the duration of acute pulmonary lesions, serum markers of inflammation and the magnitude of virus-specific T cell expansion but does not impair viral clearance. We also show that IL-10 induces the subsequent differentiation of virus-specific effector T cells into CD69+CD103+ tissue resident memory cells (Trm) in the airways and maintains Trm cells in nasal mucosal surfaces, highlighting an unexpected role for IL-10 in promoting airway memory T cells during SARS-CoV-2 infection of macaques. Author summary: Here we examine the roles of the prototypic pro- and anti-inflammatory cytokines IFNγ and IL-10 during SARS-CoV-2 infection of rhesus macaques. Whole body 18FDG-PET-CT imaging showed that IFNγ promotes SARS-CoV-2 induced pulmonary disease and IL-10 dampens the size, activity, and duration of lung lesions induced after infection. We also find a major role for IL-10 in the regulation of SARS-CoV-2-specific T cell responses. Our data show that IL-10 limits the magnitude of the effector T cell clonal burst during the acute phase of infection. We also find that following clearance of the virus, IL-10 promotes the differentiation of lung effector T cells into CD69+CD103+ tissue resident memory cells. [ABSTRACT FROM AUTHOR]

Objective(s): The bio-distribution of Tc-99m HMPAO labeled platelets (LP), which could be used to image subtle thrombosis, is not reported in a human yet, which is the subject of the current study. Method: The platelets were extracted from 49 ml whole blood and labeled with Tc-99m HMPAO, then re-injected to the healthy volunteer. Anterior and posterior whole body imaging was done by a dual-head gamma camera 3, 18, 33, 46, 81, 124, 190 min and 15 hours after injection. Also a whole-body SPECT was done at 137 min post-injection. The area under the curves of the spleen, liver, left kidney, bladder, right lung, brain, and abdominal aorta ROIs was calculated to estimate the accumulation of labeled platelets within the organs. Results: The spleen was the target organ. The kidneys, liver, and heart were also remarkably visualized. The thyroid, stomach, bladder, or gastrointestinal (GI) uptake/activity was not significant. The stomach visualization was enhanced after ingestion at 60 min. The sagittal and lateral sinuses were delineated, and the background of the brain was very low. During the study, the area under the curve of activity was 738, 308, 302, 196, 230, 121, 79, 216, 529, 369, 162, and 54 counts. min/pixel for spleen, liver, heart, right lung, left kidney, right iliac artery, sagittal sinus, thyroid, bladder, stomach, GI, and background, respectively. Conclusion: The quality of the scan with low dose Tc-99m HMPAO LPs is optimal. We documented the bio-distribution of LPs. The optimal imaging time was 80-120 min post-injection when the free Tc-99m and GI transit were negligible. The sagittal and lateral sinuses were visualized enabling detection of possible clots in the vessels. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the earliest optimal timing for positron emission tomography (PET) scans after 68Ga-fibroblast activation protein inhibitor-04 ([68Ga]Ga-FAPI-04) injection. Methods: This prospective study enrolled patients who underwent 60-min dynamic 68Ga-FAPI-04 total-body PET/CT scans; the images were reconstructed at 10-min intervals (G0-10, G10-20, G20-30, G30-40, G40-50, and G50-60), and the [68Ga]Ga-FAPI-04 uptake patterns were evaluated. The standardised uptake value (SUV), liver signal-to-noise ratio (SNR), and lesion-to-background ratios (LBRs) for different time windows were calculated to evaluate image quality and lesion detectability. The period from 30 to 40 min was then split into overlapping 5-min intervals starting 1 min apart for further evaluation. G50-60 was considered the reference. Results: A total of 30 patients with suspected malignant tumours were analysed. In the images reconstructed over 10-min intervals, longer acquisition times were associated with lower background uptake and better image quality. Some lesions could not be detected until G30-40. The lesion detection rate, uptake, and LBRs did not differ significantly among G30-40, G40-50, and G50-60 (all p > 0.05). The SUVmean and LBRs of primary tumours in the reconstructed images did not differ significantly among the 5-min intervals between 30 and 40 min; for metastatic and benign lesions, G34-39 and G35-40 showed significantly better SUVmean and LBR values than the other images. The G34-39 and G50-60 scans showed no significant differences in uptake, LBRs, or detection rates (all p > 0.05). Conclusion: The earliest optimal time to start acquisition was 34 min after injection of half-dose [68Ga]Ga-FAPI-04. Clinical relevance statement: This study evaluated 68Ga-fibroblast activation protein inhibitor-04 ([68Ga]Ga-FAPI-04) uptake patterns by comparing the image quality and lesion detection rate with 60-min dynamic [68Ga]Ga-FAPI-04 total-body PET/CT scans and identified the earliest optimal scan time after [68Ga]Ga-FAPI-04 injection. Key Points: • A prospective single-centre study showed that the earliest optimal time point to start acquisition was 34 min after injection of half-dose [68Ga-fibroblast activation protein inhibitor-04 (68Ga]Ga-FAPI-04). • There were statistically significant differences in standardised uptake value, lesion-to-background ratios, and lesion detectability between scans before and after 34 min from the injection of [68Ga]Ga-FAPI-04, but these values did not change further from 34 to 60 min after injection. • With a reasonable acquisition time, the image quality could still meet diagnostic requirements. [ABSTRACT FROM AUTHOR]

Purpose: To utilize the transmit radiofrequency (RF) field in MRI as a power source, near or within the field of view but without affecting image quality or safety. Methods: Power harvesting is performed by RF induction in a resonant coil. Resulting RF field distortion in the subject is canceled by a selective shield that couples to the harvester while being transparent to the RF transmitter. Such shielding is designed with the help of electromagnetic simulation. A shielded harvester of 3 cm diameter is implemented, assessed on the bench, and tested in a 3T MRI system, recording power yield during typical scans. Results: The concept of selective shielding is confirmed by simulation. Bench tests show effective power harvesting in the presence of the shield. In the MRI system, it is confirmed that selective shielding virtually eliminates RF perturbation. In scans with the harvester immediately adjacent to a phantom, up to 100 mW of average power are harvested without affecting image quality. Conclusion: Selective shielding enables stealthy RF harvesting which can be used to supply wireless power to on‐body devices during MRI. [ABSTRACT FROM AUTHOR]

Background: Fibroblast activation protein (FAP) has emerged as a promising target for diagnosis and therapeutic intervention due to high expression and accumulation in the stromal compartments of a variety of malignant tumors. FAP-2286 utilizes cyclic peptides with FAP-binding characteristics to enhance the retention of the imaging agent within tumors, in contrast to the small-molecule FAP inhibitors (FAPI) like FAPI-04/46. The aim of this study was to quantify the tumor uptake of [68Ga] Gallium-FAP-2286 within primary solid tumors, adjacent excised tissues, and metastatic lesions. Methods: In this prospective study, 21 patients (average age 51.9) with various diagnoses of remaining and metastatic cancers participated. Among them, six had metastatic sarcoma, and 14 had adenocarcinoma, including eight breast, two rectum, two lung, two pancreas, and one thyroid cases. The patients underwent a [68Ga]Ga-FAP-2286 PET/CT scan. An hour post-administration of [68Ga]Ga-FAP-2286, a visual assessment of whole body scans and semi-quantification of the PET/CT results were carried out. The standardized uptake values (SUV)max of [68Ga]Ga-FAP-2286 in tumor lesions and the tumor-to-background ratio (TBR) were then calculated. Results: The vital signs of the patients, such as heart rate, blood pressure, and temperature, were observed before, during, and after the diagnostic procedure during the 4-h follow-up. All individuals underwent the [68Ga]Ga-FAP-2286 PET/CT scans without any signs of drug-associated pharmacological effects. The PET/CT scans displayed substantial absorption of [68Ga]Ga-FAP-2286 in tumor lesions in all patients (100% (21/21)). Irrespective of the tumors' origins (epithelial or mesothelium) and whether they exhibited local recurrence, distant recurrence, or metastatic lesions, the PET/CT scans revealed the uptake of [68Ga]Ga-FAP-2286 in these lesions. Conclusion: Overall, these data suggest that [68Ga]Ga-FAP-2286 is a promising FAP derivative for efficient metastatic cancer diagnosis and being considered as a potential compound for therapeutic application in patients with advanced metastatic cancers. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to determine the feasibility and limitations of deep learning–based coronary calcium scoring using positron emission tomography-computed tomography (PET-CT) in comparison with coronary calcium scoring using ECG-gated non-contrast-enhanced cardiac computed tomography (CaCT). Materials and methods: A total of 215 individuals who underwent both CaCT and PET-CT were enrolled in this retrospective study. The Agatston method was used to calculate the coronary artery calcium scores (CACS) from CaCT, PET-CT(reader), and PET-CT(AI) to analyse the effect of using different modalities and AI-based software on CACS measurement. The total CACS and CACS classified according to the CAC-DRS guidelines were compared between the three sets of CACS. The differences, correlation coefficients, intraclass coefficients (ICC), and concordance rates were analysed. Statistical significance was set at p < 0.05. Results: The correlation coefficient of the total CACS from CaCT and PET-CT(reader) was 0.837, PET-CT(reader) and PET-CT(AI) was 0.894, and CaCT and PET-CT(AI) was 0.768. The ICC of CACS from CaCT and PET-CT(reader) was 0.911, PET-CT(reader) and PET-CT(AI) was 0.958, and CaCT and PET-CT(AI) was 0.842. The concordance rate between CaCT and PET-CT(AI) was 73.8%, with a false-negative rate of 37.3% and a false-positive rate of 4.4%. Age and male sex were associated with an increased misclassification rate. Conclusions: Artificial intelligence–assisted CACS measurements in PET-CT showed comparable results to CACS in coronary calcium CT. However, the relatively high false-negative results and tendency to underestimate should be of concern. Clinical relevance statement: Application of automated calcium scoring to PET-CT studies could potentially select patients at high risk of coronary artery disease from among cancer patients known to be susceptible to coronary artery disease and undergoing routine PET-CT scans. Key Points: • Cancer patients are susceptible to coronary disease, and PET-CT could be potentially used to calculate coronary artery calcium score (CACS). • Calcium scoring using artificial intelligence in PET-CT automatically provides CACS with high ICC to CACS in coronary calcium CT. • However, underestimation and false negatives of CACS calculation in PET-CT should be considered. [ABSTRACT FROM AUTHOR]

Noncontiguous 2-level cervical disc herniation (NCT-CDH) is a common condition that often requires surgical intervention. In this study, we developed a surgical approach for the treatment of NCT-CDH using anterior percutaneous full-endoscopic single incision through the vertebral body. We provide a brief overview of its safety, efficacy, and feasibility, along with a description of our relevant surgical experience. A retrospective study was conducted, involving 30 patients who were followed up for at least 12 months. Preoperative and postoperative visual analog scale, Japanese Orthopedic Association scores, Nurick scores, intervertebral disc height, and modified Macnab criteria were recorded. Patients underwent regular radiological evaluations throughout the follow-up period. Postoperative computed tomography, magnetic resonance imaging, and X-ray examinations revealed bone tunnel healing, intact drilled vertebral bodies without collapse, adequate decompression of the spinal canal, and normal cervical mobility. There was a significant improvement in postoperative visual analog scale, Japanese Orthopedic Association scores, Nurick scores, and modified Macnab criteria compared to the preoperative values (P < 0.05). Our study revealed that the anterior percutaneous full-endoscopic transcorporeal with single-incision treatment for NCT-CDH is a safe and feasible surgical method. Therefore, it can be considered as a viable treatment option for patients with NCT-CDH. [ABSTRACT FROM AUTHOR]

This study aimed to study the accuracy of pedicle screw (PS) insertion into dysplastic pedicles in adolescent idiopathic scoliosis (AIS) comparing cannulated screw using the pedicle expansion technique (PET) versus conventional technique. Forty-two AIS patients with 766 PSs were evaluated. In total, 236 screws were inserted into dysplastic pedicles: 138 and 98 screws were inserted using the PET (PET group) and standard technique (conventional group), respectively. Both methods used CT-based navigation to determine the insertion point. In the PET, a rigid ball tip feeler was tapped with a mallet to create an insertion route, a guide wire was passed through the tap, the pedicle was enlarged, and then a cannulated PS with a diameter of 4.35 mm was inserted. Postoperative CT was used to compare the accuracy of PS insertion. In total, 23/236 (9.7%) perforations occurred. Regarding overall perforation, there were six (4.3%) and 17 (17.3%) cases in the PET and conventional group, respectively (P = 0.008). In terms of medial perforation, the PET group (n = 2, 1.4%) was significantly better than the conventional group (n = 7, 7.1%) (P = 0.021). In terms of lateral perforation, the PET group (n = 4, 2.9%) was significantly better than conventional group (n = 10, 10.2%) (P = 0.030). Only grade 1 perforation had occurred in the PET group, whereas grades 2 and 3 perforation occurred in the conventional group. Use of the PET with CT-based navigation significantly increased the accuracy and safety of PS insertion in dysplastic pedicles in AIS. [ABSTRACT FROM AUTHOR]

Objectives: To assess the evolution of administered radiotracer activity for F-18-fluorodeoxyglucose (18F-FDG) PET/CT or PET/MR in pediatric patients (0–16 years) between years 2000 and 2021. Methods: Pediatric patients (≤ 16 years) referred for 18F-FDG PET/CT or PET/MR imaging of the body during 2000 and 2021 were retrospectively included. The amount of administered radiotracer activity in megabecquerel (MBq) was recorded, and signal-to-noise ratio (SNR) was measured in the right liver lobe with a 4 cm3 volume of interest as an indicator for objective image quality. Descriptive statistics were computed. Results: Two hundred forty-three children and adolescents underwent a total of 466 examinations. The median injected 18F-FDG activity in MBq decreased significantly from 296 MBq in 2000–2005 to 100 MBq in 2016–2021 (p < 0.001), equaling approximately one-third of the initial amount. The median SNR ratio was stable during all years with 11.7 (interquartile range [IQR] 10.7–12.9, p = 0.133). Conclusions: Children have benefited from a massive reduction in the administered 18F-FDG dose over the past 20 years without compromising objective image quality. Clinical relevance statement: Radiotracer dose was reduced considerably over the past two decades of pediatric F-18-fluorodeoxyglucose PET/CT and PET/MR imaging highlighting the success of technical innovations in pediatric PET imaging. Key Points: • The evolution of administered radiotracer activity for F-18-fluorodeoxyglucose (18F-FDG) PET/CT or PET/MR in pediatric patients (0–16 years) between 2000 and 2021 was assessed. • The injected tracer activity decreased by 66% during the study period from 296 megabecquerel (MBq) to 100 MBq (p < 0.001). • The continuous implementation of technical innovations in pediatric hybrid 18F-FDG PET has led to a steady decrease in the amount of applied radiotracer, which is particularly beneficial for children who are more sensitive to radiation. [ABSTRACT FROM AUTHOR]

Traditional planar iodine-131 whole-body scan (WBS), which is frequently used to find radioiodine-avid metastases in thyroid cancer patients, is regarded as the standard diagnostic method. The constraints of planar iodine-131 whole-body scan in iodine-avid metastases have been addressed using SPECT/CT. The aim of this study was to compare iodine-131 SPECT/CT in the diagnosis of metastasis intermediate- and high-risk with thyroid carcinoma by radioactive iodine as therapy versus planar imaging. In a cross-sectional study, to sixty patients with diagnosed thyroid cancer 43 women and 17 men, ages 11 - 76 years to were examined at both the nuclear medicine sections of the Al-Andalus Private Hospital in Baghdad and the Al-Kawthar Nuclear Medicine Center in Basra. All patients had full or nearly full thyroid surgery. They received dose treatment with radioactive iodine-131 ranging from 3.7 GBq (100 mci) to 7.4 GBq (200 mci), after 5 days following the dosage, they had a planar whole body scan as well as SPECT/CT for the same day. Planar whole body scan and SPECT/CT data had been interpreted very differently for lymph node metastases and distant metastases, identifying sites of iodine uptake in some patients as it was judged equivocal, especially in the neck area, where the frequency of equivocal foci and middle cervical action was classified as a locoregional or thyroid residual illness. SPECT/CT interpreted the foci of iodine uptake sites thought to be equivocal detected on planar imaging. The results of the current study showed that the interpretation of uptake foci on whole-body planar imaging changed when the SPECT/CT results were reviewed, and the treatment plan had changed in 26 (43%) of 60 patients. This change was due to dependence on iodine uptake sites in the foci. The combination of SPECT/CT images had an increased greater than iodine-131 in planar scans in accurately defining central neck activity, and the incidence of radioactive avid metastases to lymphatic nodes (LN) on SPECT/CT was unusually large. SPECT/CT showed significantly more diagnostic data and additional benefit over whole-body planar scan for patients who received an oral therapeutic dose of iodine-131. [ABSTRACT FROM AUTHOR]

Most seismic data used for conventional exploration lack far‐offset signals and effective low‐frequency components. This makes it difficult for conventional full waveform inversion methods to recover the low‐wavenumber components of mid‐ and deep‐layer models. To resolve the bottleneck of ray‐theoretical reflection traveltime tomography, wave equations, such as reflection inversion methods, are receiving increasing attention. We reconstructed a wide‐spectrum velocity model based on the multiscale wave‐equation reflection inversion method for model decomposition. First, using the dynamic image warping method to obtain reflection traveltime residuals, the wave‐equation reflection traveltime inversion was used to recover the low‐wavenumber components of the background model, which also solved the cycle‐skipping problem. Second, the medium‐wavenumber component of the model is then supplemented by the reflection waveform inversion, while the reflectivity model is obtained relying on the least‐squares reverse time migration method. Based on this method, the background and perturbation models are updated alternately and iteratively. At the same time, the stratum structural tensor information was extracted using the perturbed model image to construct a preconditioned operator for the stratum structural constraint, suppress unreasonably high‐wavenumber components in the generalized gradient and improve the geological consistency of the inversion results. Testing of the model using the Sigsbee2b model and seismic field data from the East China Sea showed that, compared with the conventional reflection traveltime tomography method based on prestack depth migration, the wave‐equation reflection inversion strategy with well‐matched information from traveltimes to waveforms significantly improved the accuracy of the middle and deep velocity modelling and enhanced the imaging quality of the whole body. [ABSTRACT FROM AUTHOR]

Gadolinium-based contrast agents (GBCAs) have helped to improve the role of magnetic resonance imaging (MRI) for the diagnosis and treatment of diseases. There are currently nine different commercially available gadolinium-based contrast agents (GBCAs) that can be used for body MRI cases, and which are classifiable according to their structures (cyclic or linear) or biodistribution (extracellular-space agents, target/specific-agents, and blood-pool agents). The aim of this review is to illustrate the commercially available MRI contrast agents, their effect on imaging, and adverse reaction on the body, with the goal to lead to their proper selection in different clinical contexts. When we have to choose between the different GBCAs, we have to consider several factors: (1) safety and clinical impact; (2) biodistribution and diagnostic application; (3) higher relaxivity and better lesion detection; (4) higher stability and lower tissue deposit; (5) gadolinium dose/concentration and lower volume injection; (6) pulse sequences and protocol optimization; (7) higher contrast-to-noise ratio at 3.0 T than at 1.5 T. Knowing the patient's clinical information, the relevant GBCAs properties and their effect on body MRI sequences are the key features to perform efficient and high-quality MRI examination. [ABSTRACT FROM AUTHOR]

A study published in the Archives of Dermatological Research compared the healing effects of using extracts and secretions from Lucilia sericata fly larvae on third-degree burn wounds in Wistar rats. The study found that maggot secretions and extracts accelerated wound healing, promoting re-epithelialization, granulation tissue formation, increased capillary count, and collagen density. The maggot treatment groups showed a significantly higher level of wound contraction compared to the control group. The study suggests that maggot therapy could be a promising method for treating burn wounds in humans. [Extracted from the article]

Incidental findings in the post-treatment whole body iodine scan (WBIS) sometimes have a broad list of differentials. We present a case of differentiated thyroid carcinoma (DTC), pT3aN1b, with family history of DTC. She was treated with adjuvant 131I therapy (5.55 GBq). The patient's post-treatment WBIS revealed a large, round iodine-avid area above the bladder, which was attributed to a massive uterine fibroid. Physical examination as well as radiologic correlation with SPECT/CT were also concordant. Fibroids can trap the radioiodine by various mechanisms. This case serves as a reminder of an uncommon pitfall in WBIS, particularly in women of reproductive age. [ABSTRACT FROM AUTHOR]

BackgroundThe accurate assessment of total body and regional body circumferences, volumes, and compositions are critical to monitor physical activity and dietary interventions, as well as accurate disease classifications including obesity, metabolic syndrome, sarcopenia, and lymphedema. We assessed body composition and anthropometry estimates provided by a commercial 3-dimensional optical (3DO) imaging system compared to criterion measures.MethodsParticipants of the Shape Up! Adults study were recruited for similar sized stratifications by sex, age (18-40, 40-60, >60 years), BMI (under, normal, overweight, obese), and across five ethnicities (non-Hispanic [NH] Black, NH White, Hispanic, Asian, Native Hawaiian/Pacific Islander). All participants received manual anthropometry assessments, duplicate whole-body 3DO (Styku S100), and dual-energy X-ray absorptiometry (DXA) scans. 3DO estimates provided by the manufacturer for anthropometry and body composition were compared to the criterion measures using concordance correlation coefficient (CCC) and Bland-Altman analysis. Test-retest precision was assessed by root mean square error (RMSE) and coefficient of variation.ResultsA total of 188 (102 female) participants were included. The overall fat free mass (FFM) as measured by DXA (54.1 ± 15.2 kg) and 3DO (55.3 ± 15.0 kg) showed a small mean difference of 1.2 ± 3.4 kg (95% limits of agreement -7.0 to +5.6) and the CCC was 0.97 (95% CI: 0.96-0.98). The CCC for FM was 0.95 (95% CI: 0.94-0.97) and the mean difference of 1.3 ± 3.4 kg (95% CI: -5.5 to +8.1) reflected the difference in FFM measures. 3DO anthropometry and body composition measurements showed high test-retest precision for whole body volume (1.1 L), fat mass (0.41 kg), percent fat (0.60%), arm and leg volumes, (0.11 and 0.21 L, respectively), and waist and hip circumferences (all

Diffusion-weighted magnetic resonance imaging (DWI) of the musculoskeletal system has various applications, including visualization of bone tumors. However, DWI acquired with echo-planar imaging is susceptible to distortions due to static magnetic field inhomogeneities. This study aimed to estimate spatial displacements of bone and to examine whether distortion corrected DWI images more accurately reflect underlying anatomy. Whole-body MRI data from 127 prostate cancer patients were analyzed. The reverse polarity gradient (RPG) technique was applied to DWI data to estimate voxel-level distortions and to produce a distortion corrected DWI dataset. First, an anatomic landmark analysis was conducted, in which corresponding vertebral landmarks on DWI and anatomic T2-weighted images were annotated. Changes in distance between DWI- and T2-defined landmarks (i.e., changes in error) after distortion correction were calculated. In secondary analyses, distortion estimates from RPG were used to assess spatial displacements of bone metastases. Lastly, changes in mutual information between DWI and T2-weighted images of bone metastases after distortion correction were calculated. Distortion correction reduced anatomic error of vertebral DWI up to 29 mm. Error reductions were consistent across subjects (Wilcoxon signed-rank p

Background: 99mTc radiolabeled nanobody NM-02 (99mTc-NM-02) is a novel single photon emission computed tomography (SPECT) probe with a high affinity and specificity for human epidermal growth factor receptor 2 (HER2). In this study, a clinical imaging trial was conducted to investigate the relationship between 99mTc-NM-02 uptake and HER2 expression in patients with breast cancer. Methods: Thirty patients with pathologically confirmed breast cancer were recruited and imaged with both 99mTc-NM-02 SPECT/computed tomography (CT) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT. According to the treatment conditions before recruitment, patients were divided into two groups, the newly diagnosed group (n = 24) and the treated group (n = 6). The maximal standard uptake value (SUVmax) of 18F-FDG and SUVmax and mean SUV (SUVmean) of 99mTc-NM-02 in the lesions were determined to analyze the relationship with HER2 expression. Results: No meaningful relationship was observed between 18F-FDG uptake and HER2 expression in 30 patients with breast cancer. 99mTc-NM-02 uptake was positively correlated with HER2 expression in the newly diagnosed group, but no correlation was observed in the treated group. 99mTc-NM-02 uptake in HER2-positive lesions was lower in those with effective HER2-targeted therapy compared with the newly diagnosed group. 99mTc-NM-02 SPECT/CT detected brain and bone metastases of breast cancer with a different imaging pattern from 18F-FDG PET/CT. 99mTc-NM-02 showed no non-specific uptake in inflamed tissues and revealed intra- and intertumoral HER2 heterogeneity by SPECT/CT imaging in 9 of the 30 patients with breast cancer. Conclusions: 99mTc-NM-02 SPECT/CT has the potential for visualizing whole-body HER2 overexpression in untreated patients, making it a promising method for HER2 assessment in patients with breast cancer. Trial registration: NCT04674722, Date of registration: December 19, 2020. [ABSTRACT FROM AUTHOR]

Objective: Uncertainty exists regarding optimal supplemental diet for very preterm infants if the mother's own milk (MM) is insufficient. We evaluated feasibility for a randomised controlled trial (RCT) powered to detect important differences in health outcomes. Methods: In this open, parallel, feasibility trial, we randomised infants 25+0–31+6 weeks of gestation by opt-out consent to one of three diets: unfortified human milk (UHM) (unfortified MM and/or unfortified pasteurised human donor milk (DM) supplement), fortified human milk (FHM) (fortified MM and/or fortified DM supplement), and unfortified MM and/or preterm formula (PTF) supplement from birth to 35+0 weeks post menstrual age. Feasibility outcomes included opt-outs, adherence rates, and slow growth safety criteria. We also obtained anthropometry, and magnetic resonance imaging body composition data at term and term plus 6 weeks (opt-in consent). Results: Of 35 infants randomised to UHM, 34 to FHM, and 34 to PTF groups, 21, 19, and 24 infants completed imaging at term, respectively. Study entry opt-out rate was 38%; 6% of parents subsequently withdrew from feeding intervention. Two infants met predefined slow weight gain thresholds. There were no significant between-group differences in term total adipose tissue volume (mean [SD]: UHM: 0.870 L [0.35 L]; FHM: 0.889 L [0.31 L]; PTF: 0.809 L [0.25 L], p = 0.66), nor in any other body composition measure or anthropometry at either timepoint. Conclusions: Randomisation to UHM, FHM, and PTF diets by opt-out consent was acceptable to parents and clinical teams, associated with safe growth profiles and no significant differences in body composition. Our data provide justification to proceed to a larger RCT. [ABSTRACT FROM AUTHOR]

Objective: Spinal and bulbar muscular atrophy (SBMA) is characterized by slow, progressive bulbar and limb muscle weakness; however, the pattern of progression of muscle fat infiltration remains unclear. We assessed the progression of muscle involvement in 81 patients with SBMA using whole‐body muscle magnetic resonance imaging (MRI), alongside clinical and laboratory findings. Methods: This prospective study included patients with genetically confirmed SBMA who underwent whole‐body muscle MRI. We analyzed muscle fat infiltration and the pattern of involved muscles using cluster analysis, visualizing the sequential progression of fat infiltration. Muscle clusters demonstrated correlation with clinical scales and laboratory findings. Additionally, linear regression analysis was performed to identify the MRI section most strongly associated with 6‐minute walk test (6MWT). Results: We included 81 patients with SBMA (age = 54.3 years). After categorizing the patients into 6 clusters based on the pattern of muscle fat infiltration, we observed that muscle involvement began in the posterior calf and progressed to the posterior thigh, pelvis, trunk, anterior thigh, medial thigh, anterior calf, and upper extremity muscles. These muscle clusters correlated significantly with disease duration (τ = 0.47, p < 0.001), 6MWT (τ = −0.49, p < 0.001), and serum creatinine level (τ = −0.46, p < 0.001). The whole‐body MRI indicated the thigh as the section most significantly correlated with 6MWT. Interpretation: We used whole‐body muscle MRI to determine the sequential progression of the fat infiltration in SBMA. Our findings may enable the identification of objective and reliable imaging outcome measures in the study of the natural history or future clinical trials of SBMA. ANN NEUROL 2024;95:596–606 [ABSTRACT FROM AUTHOR]

Objectives: Stereotactic body radiotherapy (SBRT) is a treatment option for patients with early-stage non-small cell lung cancer (NSCLC) who are unfit for surgery. Some patients may experience distant metastasis. This study aimed to develop and validate a radiomics model for predicting distant metastasis in patients with early-stage NSCLC treated with SBRT. Methods: Patients at five institutions were enrolled in this study. Radiomics features were extracted based on the PET/CT images. After feature selection in the training set (from Tianjin), CT-based and PET-based radiomics signatures were built. Models based on CT and PET signatures were built and validated using external datasets (from Zhejiang, Zhengzhou, Shandong, and Shanghai). An integrated model that included CT and PET radiomic signatures was developed. The performance of the proposed model was evaluated in terms of its discrimination, calibration, and clinical utility. Multivariate logistic regression was used to calculate the probability of distant metastases. The cutoff value was obtained using the receiver operator characteristic curve (ROC), and the patients were divided into high- and low-risk groups. Kaplan-Meier analysis was used to evaluate the distant metastasis-free survival (DMFS) of different risk groups. Results: In total, 228 patients were enrolled. The median follow-up time was 31.4 (2.0-111.4) months. The model based on CT radiomics signatures had an area under the curve (AUC) of 0.819 in the training set (n = 139) and 0.786 in the external dataset (n = 89). The PET radiomics model had an AUC of 0.763 for the training set and 0.804 for the external dataset. The model combining CT and PET radiomics had an AUC of 0.835 for the training set and 0.819 for the external dataset. The combined model showed a moderate calibration and a positive net benefit. When the probability of distant metastasis was greater than 0.19, the patient was considered to be at high risk. The DMFS of patients with high- and low-risk was significantly stratified (P < 0.001). Conclusions: The proposed PET/CT radiomics model can be used to predict distant metastasis in patients with early-stage NSCLC treated with SBRT and provide a reference for clinical decision-making. Plain language summary: In this study, the model was established by combining CT and PET radiomics signatures in a moderate-quantity training cohort of early-stage NSCLC patients treated with SBRT and was successfully validated in independent cohorts. Physicians could use this easy-to-use model to assess the risk of distant metastasis after SBRT. Identifying subgroups of patients with different risk factors for distant metastasis is useful for guiding personalized treatment approaches. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to assess the efficacy of machine learning and radiomics analysis using magnetic resonance imaging (MRI) with a hepatospecific contrast agent, in a pre-surgical setting, to predict tumor budding in liver metastases. Methods: Patients with MRI in a pre-surgical setting were retrospectively enrolled. Manual segmentation was made by means 3D Slicer image computing, and 851 radiomics features were extracted as median values using the PyRadiomics Python package. Balancing was performed and inter- and intraclass correlation coefficients were calculated to assess the between observer and within observer reproducibility of all radiomics extracted features. A Wilcoxon–Mann–Whitney nonparametric test and receiver operating characteristics (ROC) analysis were carried out. Balancing and feature selection procedures were performed. Linear and non-logistic regression models (LRM and NLRM) and different machine learning-based classifiers including decision tree (DT), k-nearest neighbor (KNN) and support vector machine (SVM) were considered. Results: The internal training set included 49 patients and 119 liver metastases. The validation cohort consisted of a total of 28 single lesion patients. The best single predictor to classify tumor budding was original_glcm_Idn obtained in the T1-W VIBE sequence arterial phase with an accuracy of 84%; wavelet_LLH_firstorder_10Percentile was obtained in the T1-W VIBE sequence portal phase with an accuracy of 92%; wavelet_HHL_glcm_MaximumProbability was obtained in the T1-W VIBE sequence hepatobiliary excretion phase with an accuracy of 88%; and wavelet_LLH_glcm_Imc1 was obtained in T2-W SPACE sequences with an accuracy of 88%. Considering the linear regression analysis, a statistically significant increase in accuracy to 96% was obtained using a linear weighted combination of 13 radiomic features extracted from the T1-W VIBE sequence arterial phase. Moreover, the best classifier was a KNN trained with the 13 radiomic features extracted from the arterial phase of the T1-W VIBE sequence, obtaining an accuracy of 95% and an AUC of 0.96. The validation set reached an accuracy of 94%, a sensitivity of 86% and a specificity of 95%. Conclusions: Machine learning and radiomics analysis are promising tools in predicting tumor budding. Considering the linear regression analysis, there was a statistically significant increase in accuracy to 96% using a weighted linear combination of 13 radiomics features extracted from the arterial phase compared to a single radiomics feature. [ABSTRACT FROM AUTHOR]

Background: Advanced positron emission tomography (PET) image reconstruction methods promise to allow optimized PET/CT protocols with improved image quality, decreased administered activity and/or acquisition times. Objective: To evaluate the impact of reducing counts (simulating reduced acquisition time) in block sequential regularized expectation maximization (BSREM) reconstructed pediatric whole-body 18F-fluorodeoxyglucose (FDG) PET images, and to compare BSERM with ordered-subset expectation maximization (OSEM) reconstructed reduced-count images. Materials and methods: Twenty children (16 male) underwent clinical whole-body 18F-FDG PET/CT examinations using a 25-cm axial field-of-view (FOV) digital PET/CT system at 90 s per bed (s/bed) with BSREM reconstruction (β=700). Reduced count simulations with varied BSREM β levels were generated from list-mode data: 60 s/bed, β=800; 50 s/bed, β=900; 40 s/bed, β=1000; and 30 s/bed, β=1300. In addition, a single OSEM reconstruction was created at 60 s/bed based on prior literature. Qualitative (Likert scores) and quantitative (standardized uptake value [SUV]) analyses were performed to evaluate image quality and quantitation across simulated reconstructions. Results: The mean patient age was 9.0 ± 5.5 (SD) years, mean weight was 38.5 ± 24.5 kg, and mean administered 18F-FDG activity was 4.5 ± 0.7 (SD) MBq/kg. Between BSREM reconstructions, no qualitative measure showed a significant difference versus the 90 s/bed β=700 standard (all P>0.05). SUVmax values for lesions were significantly lower from 90 s/bed, β=700 only at a simulated acquisition time of 30 s/bed, β=1300 (P=0.001). In a side-by-side comparison of BSREM versus OSEM reconstructions, 40 s/bed, β=1000 images were generally preferred over 60 s/bed TOF OSEM images. Conclusion: In children who undergo whole-body 18F-FDG PET/CT on a 25-cm FOV digital PET/CT scanner, reductions in acquisition time or, by corollary, administered radiopharmaceutical activity of >50% from a clinical standard of 90 s/bed may be possible while maintaining diagnostic quality when a BSREM reconstruction algorithm is used. [ABSTRACT FROM AUTHOR]

Somatostatin receptor (SST) PET/CT is the gold standard for well‐differentiated neuroendocrine tumours (NET) imaging. Higher grades of neuroendocrine neoplasms (NEN) show preferential [18F]FDG (FDG) uptake, and even low‐grade NET may de‐differentiate over time. FDG PET/CT's prognostic role is widely accepted; however, its impact on clinical decision‐making remains controversial and its use varies widely. A questionnaire‐based survey on FDG PET/CT use and perceived decision‐making utility in NEN was submitted to the ENETS Advisory Board Meeting attendees (November 2022, response rate = 70%). In 3/15 statements, agreement was higher than 75%: (i) FDG was considered useful in NET, irrespective of grade, in case of mis‐matched lesions (detectable on diagnostic CT but negative/faintly positive on SST PET/CT), especially if PRRT is contemplated (80%); (ii) in NET G3 if curative surgery is considered (82%); and (iii) in NEC prior to surgery with curative intent (98%). FDG use in NET G3, even in the presence of matched lesions, as a baseline for response assessment was favoured by 74%. Four statements obtained more than 60% consensus: (i) FDG use in NET G3 if locoregional therapy is considered (65%); (ii) in neuroendocrine carcinoma before initiating active therapy as a baseline for response assessment (61%); (iii) biopsy to re‐assess tumour grade prior to a change in therapeutic management (68%) upon detection of FDG‐positivity on the background of a prior G1‐2 NET; (iv) 67% were in favour to reconsider PRRT to treat residual SST‐positive lesions after achieving complete remission on FDG of the SST‐negative disease component. Multidisciplinary opinion broadly supports the use of FDG PET/CT for characterisation of disease biology and to guide treatment selection across a range of indications, despite the lack of full consensus in many situations. This may reflect existing clinical access due to lack of reimbursement or experience with this investigation, which should be addressed by further research. [ABSTRACT FROM AUTHOR]