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This study was to evaluate the effects of an ultra-low dose of [18F]-FDG on the image quality of total-body PET/CT and its lesion detectability in colorectal cancer (CRC). Sixty-two CRC patients who underwent total-body PET/CT (uEXPLORER, United Imaging Healthcare, Shanghai, China) with an ultra-low dose (0.37 MBq/kg) of [18F]-FDG were enrolled in this retrospective study. The PET images were reconstructed with the entire 15-min dataset first and then split into 13-, 8-, 5-, 4-, 3-, 2-, and 1-min duration groups to simulate fast scanning images. For simplicity, the images reconstructed with the data from 15 to 1 min were referred to as G15, G13, and so on until G1. Subjective image quality was assessed with 5-point Likert scales. The objective image quality parameters included the SUVmax, SUVmean, and signal-to-noise ratio (SNR) of the liver and blood pool and the SUVmax and tumor-to-background ratio (TBR) of the lesions. G15 served as the control to evaluate lesion detectability. A total of 62 patients (43 men, 19 women; age 41–88, mean ± SD 64.0 ± 10.9 years) with 64 CRC primary tumor lesions and 10 low-grade intraepithelial neoplasia (LGIN) lesions were enrolled in this study. The subjective scores were highest for G15 (4.5 ± 0.5) and then decreased from G13 (4.3 ± 0.4) to G8 (3.7 ± 0.5). The liver SNR increased with the extension of acquisition time from G8 (17.2 ± 2.8) to G13 (20.6 ± 3.4) and G15 (21.9 ± 3.4). The liver SNR of G8 was not significantly different from that of G13 (p = 0.15) and was significantly different from that of G15 (p = 0.001). All 64 CRC lesions could be identified in all image groups, even on G1. One of ten LGINs was missed on G1, G2, and G3, and one LGIN was missed on G1, G2, G3, and G4. G15 served as the control, and 100% (48/48) lymph nodes could be found on G13 and G8 compared to 93.8% (45/48) lymph nodes on G5 and G4, 85.4% (41/48) lymph nodes on G3, 81.3% (39/48) lymph nodes on G2, and 77.1% (37/48) lymph nodes on G1. For liver metastases, there were no missed liver lesions on G13 and G8 and 3, 4, 6, 7, and 9 missed liver lesions on G5, G4, G3, G2, and G1, respectively. For other areas of metastasis, including the lung, peritoneum, and ovaries, there were no missed lesions in any group. Total-body PET/CT with an ultra-low dose of [18F]-FDG can maintain satisfactory image quality and lesion detectability in CRC.

The injection activity of tracer, acquisition time, patient-specific photon attenuation, and large body mass, can influence on image quality. Fixed acquisition time and body mass related injection activity in clinical practice results in a large difference in image quality. Thus, this study proposes a patient-specific acquisition time regimen ofThe development cohort consisting of 19 consecutive patients with full activity (88.7-204.9 MBq, 2.0 ± 0.1 MBq/kg) was to establish the acquisition time regimen. The liver SNR (signal-to-noise ratio, SNRThe linear correlation (RA patient-specific acquisition time regimen was proposed in NET patients in development cohort and validated its feasibility in patients with NETs in validation cohort by

OBJECTIVES We recently reported a high rate of nontherapeutic thymectomy. Mediastinal lymphomas (MLs) are the malignancies most likely to be confused with thymic epithelial tumours (TETs). This study aimed to establish a predictive model by evaluating clinical variables and positron emission tomography to distinguish those diseases. METHODS From 2018 to 2021, consecutive patients who were pathologically diagnosed with TETs or MLs were retrospectively reviewed. Univariable and multivariable analyses were used to identify association factors. The Akaike information criterion was used to select variables. A nomogram was developed and validated to differentiate MLs from TETs. RESULTS A total of 198 patients were included. Compared with TETs, patients with MLs were more likely to be younger with higher metabolic tumour volume (154.1 vs 74.6 cm3), total lesion glycolysis (1388.8 vs 315.2 g/ml cm3), SUVmean (9.2 vs 4.8), SUVpeak (12.9 vs 6.3) and SUVmax (14.8 vs 7.5). A nomogram was established based on the stepwise regression results and the final model containing age and SUVmax had minimal Akaike information criterion value of 72.28. Receiver operating characteristic analyses indicated that the area under the curve of predictive nomogram in differentiating MLs from TETs was 0.842 (95% CI: 0.754–0.907). The internal bootstrap resampling and calibration plots demonstrated good consistence between the prediction and the observation. CONCLUSIONS Combination of age and SUVmax appears to be a useful tool to differentiate MLs from TETs. The novel predictive model prevents more patients from receiving nontherapeutic thymectomy.

The purpose of this study was to investigate image quality and lesion detectability of half-dose (1.85 MBq/kg) 18 F-fluorodeoxyglucose (FDG) total-body positron emission tomography/computed tomography (PET/CT) for colorectal cancer, full-dose (3.7 MBq/kg) 18 F-FDG serving as a reference.Fifty patients confirmed to have colorectal cancer who underwent total-body PET/CT with half-dose 18 F-FDG were included. Another 50 colorectal cancer patients with 3.70 MBq/kg 18 F-FDG activity were selected for the full-dose group. PET images in the half-dose group were scanned for 15 min and split into 1-, 2-, 3-, 4- and 10-min duration groups, denoted G1, G2, G3, G4 and G10, respectively. In the full-dose group, PET scanning was performed for 5 min, reconstructed with the first 0.5, 1, 2 and 5 min intervals, defined as G0.5', G1', G2' and G5', respectively. Subjective image quality was assessed with 5-point Likert scales. Objective image quality parameters included maximum standardized uptake values (SUV max) , mean standardized uptake values (SUV mean )and signal-to-noise ratio (SNR) of the liver, blood pool and muscle and SUV max and tumor-to-background ratio (TBR) of lesions.In the two groups, the G3 and G2' images met clinical diagnosis requirements in terms of subjective image quality, with scores ≥3. There were no differences in terms of subjective and objective image quality between the groups (G1 and G0.5', G2 and G1', G4 and G2' and G10 and G5'). In the half-dose group, 56 colorectal lesions in 50 patients confirmed by surgical pathology were clearly visible in all groups. The number of FDG-avid lymph nodes was 37 in G1, 38 in G2 and 39 in the remaining half-dose groups. The number of missed metastatic liver lesions was 1 both in G1 and G2.Total-body PET/CT with half-dose was feasible for diagnosing and staging colorectal cancer compared with full-dose 18 F-FDG PET/CT. Moreover, for half-dose total-body PET/CT, a 3-min scan duration could maintain image quality and lesion detectability.

To explore the feasibility of ultralow-activityEight of 18 patients were randomly injected withEach of the fitted models has a satisfactory goodness-of-fit with RThe 10 × reduction of injected

It is very rare for papillary thyroid cancer metastasize to nasopharynx. We report FDG PET/CT findings of a solitary nasopharyngeal metastasis from papillary thyroid cancer 4 decades after the initial diagnosis in a 66-year-old woman, which mimics nasopharyngeal carcinoma. The final diagnosis was confirmed by pathological examination from the biopsy of nasopharyngeal lesion.

The purpose was to explore the effects of total-body PET/CT with half-dose 18F-FDG activity on image quality, compared with those of conventional PET/CT with clinical routine full-dose 18F-FDG in lung cancer. Fifty-six primary lung cancer patients who underwent total-body PET/CT on a uEXPLORER scanner with half-dose (1.85 MBq/kg) 18F-FDG activity before treatment were retrospectively studied; among them, 28 patients were confirmed by postoperative pathologic examination and 28 patients by biopsy. After matching with the pathological study results, the other 28 patients with lung cancer who underwent surgery were selected for the full-dose (3.70 MBq/kg) group. Patients in the full-dose group were studied with a conventional uM780 PET/CT scanner. The acquisition time of the half-dose group was 15 min, split into 4-min and 2-min duration groups, which were all referred to as G15, G4 and G2, respectively. The PET/CT scanning speed in the full-dose group was 2 min/bed. Image quality was evaluated by subjective and objective analyses. The subjective analysis method was carried out with a 5-point scale (5-excellent, 1-poor). Objective analysis indicators of PET image quality included the SUVmax, SUVmean and signal-to-noise ratio (SNR) of the liver; the SUVmax and SUVmean of the blood pool; and the SUVmax and tumour-to-background ratio (TBR) of the lesions. G15 served as the reference for G2 and G4 to test lesion detectability. Image quality scores in G2 (4.3 ± 0.7) were significantly higher than those in the full-dose group (3.7 ± 0.6) (p = 0.004). The mean and SD of the image quality scores in G4 and G15 were 4.9 ± 0.2 and 5.0 ± 0.0, respectively. The liver SNR in G2 was significantly higher than that in the full-dose group; the corresponding SNR were 11.7 ± 1.5 and 8.3 ± 1.2 (p

OBJECTIVE. The purpose of this article is to describe the clinical applications of a total-body PET scanner and discuss future expectations. CONCLUSION. PET has been widely used in the fields of oncology, neurology, and cardiology. However, current PET scanners have limitations, including long scanning time, low signal-to-noise ratio, and high dose of ionizing radiation. Total-body PET with a long scan range provides solutions to these problems, markedly increasing the sensitivity of the system.

Objective The uptake of F-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) is known to be linked to programmed death ligand 1 (PD-L1) expression on tumor cells (TC). However, the association between PD-L1 expression on immune cells (IC) and F-FDG accumulation is still unclear. Here, we conducted a clinicopathological study to investigate the relationship between PD-L1 expression on TC/IC and F-FDG uptake in patients with surgically resected pulmonary adenocarcinoma (ADC). Methods A total of 450 ADC patients who underwent preoperative F-FDG-PET/CT imaging were analyzed retrospectively. Immunohistochemistry analysis was performed for PD-L1 expression on TC and IC in ADC specimens with SP142. PD-L1 expression was performed on whole-tissue sections and given scores (0/1/2/3) according to percent of PD-L1 cells in TC and IC. Results Compared to TC0 and IC0, PD-L1 positive expression was 90.4% (407/450) in ADC specimens. Both PD-L1 expression score on TC and IC were associated with maximum standardized uptake (SUVmax). SUVmax augmented with increasing PD-L1 expression (TC0 and IC0, 4.3 ± 3.4; TC or IC1/2/3, 7.7 ± 5.6; TC or IC2/3, 8.1 ± 5.6; TC or IC3, 8.4 ± 5.4). The best cut-off value of PD-L1 expression, determined by receiver operating characteristic curve, was 5.1 for TC or IC1/2/3 [area under the curve (AUC) = 0.713, sensitivity 62.2%, specificity 72.1%]. Multivariate analysis demonstrated that TC or IC1/2/3 subset was correlated with histological subtype, PD-1 expression on IC and SUVmax. Conclusion High SUVmax is associated with PD-L1 expression on TC and IC in surgically resected pulmonary ADC. F-FDG-PET/CT imaging can be a potential tool to evaluate PD-L1 expression in pulmonary ADC.

Gastric cancer (GC) is a common cancer worldwide, with high incidence and mortality rates. Therefore, early and precise diagnosis is critical to improving GC prognosis. Tumor-associated myeloid cells infiltrate the tumor microenvironment (TME) and can produce immunosuppressive effects in the early stage of the tumor. The surface integrin receptor CD11b is widely expressed in the specific subsets of myeloid cells, and it has the characteristics of high abundance, high specificity, and high potential for targeted immunotherapy. In this study, two strategies for labeling anti-CD11b, including

P2X7 receptors have been considered as a promising biomarker for vulnerable atherosclerotic plaques, which are highly expressed by that instability-associated factors such as macrophages. Thus, we aim to investigate the feasibility of using specific P2X7-targetedThe radioligandWe innovatively apply a new type P2X7-targeted PET probe (

To comparatively evaluate the diagnostic performances of total-bodyThis study included 156 patients with liver tumours. Seventy-eight patients underwent total-body PET/CT. PET raw data were reconstructed using acquisition durations of 2 min (G2) and 15 min (G15). Another 78 patients with liver lesions (control patients) underwent conventional uMI780 PET/CT (G780). All patients were evaluated based on TNM staging. The maximum tumour standardized uptake value (tumour SUVmax), mean normal liver SUV (SUVmean), and tumour SUVmax-to-liver SUVmean ratio (TLR) were determined for all patients. G15 data were used as the reference in the lesion detectability analysis. The diagnostic performances of PET/CT in terms of visual parameters and of PET in terms of semi-quantitative parameters such as SUVmax and TLR were evaluated. Receiver operating characteristics (ROC) curve analysis of SUVmax and TLR at G2 was performed. Pathologic findings of surgical specimens served as the gold standard for all patients.The lesions found in G15 were also noted in G2; three lymph nodes were missed in G2. However, no significant difference was found in the TNM stage among G2, G15, and G780. For benign and malignant lesions, the liver SUVmean in G2 and G15 was higher than that in G780 (all P 0.05). The tumour SUVmax and TLR in G2 were equivalent to those in G15 and G780 regardless of whether the lesions were benign or malignant. ROC curve analysis (SUVmax cutoff: 4.34, TLR cutoff: 1.34) demonstrated that G2 also had good sensitivity in detecting liver cancer.The diagnostic performance of total-body PET/CT in G2 was comparable to that in G15 among liver cancer patients. Further, the diagnostic efficiency of total-body PET/CT imaging with fast 2-min acquisition and conventional PET/CT was similar.

To investigate the correlation among the maximum standardized uptake value (SUVmax) on fluorine-18-fluorodeoxyglucose (TheAmong the 116 lesions, 45, 51, and 20 lesions were classified into the moderately differentiated, moderately-poorly, and poorly differentiated groups, respectively. There were significant differences in the SUVmax (P=0.033) and TNR (P=0.044) among the three groups. Maximum SUV was significantly correlated with differentiation (r=0.244, P=0.008). When the cases were categorized according to the tumor size (group 1, ≤3cm, n=14; group 2,3 and ≤5 cm, n=37; group 3,5 and ≤10 cm, n=52; group 4,10 cm, n=13), there were significant differences in the SUVmax (P0.001) and TNR (P0.001) among the four groups. Maximum SUV was significantly correlated with tumor size (r=0.481, P0.001). Among the 116 lesions, 38 lesions and 78 lesions were classified into the low Ki67 and high Ki67 expression groups, respectively. There were significant differences in the SUVmax (P=0.028) and TNR (P=0.007) between the two groups. Maximum SUV was significantly correlated with Ki67 expression (r=0.242, P=0.009).In moderately and poorly differentiated ICC, the SUVmax and TNR are significantly associated with tumor differentiation, size, and Ki67 expression.

Mutations in isocitrate dehydrogenase 1 (IDH1) are commonly found in various human malignancies. Inhibitors of several mutant IDH1 enzymes have entered clinical trials as target therapeutic drugs for the treatment of patients with IDH1 mutations. Herein, we report the synthesis and evaluation of two

A 70-year-old woman with lumbar and renal tuberculosis underwent 99mTc-DTPA renal scintigraphy to evaluate renal function before lumbar lesion resection and nephrectomy. The images incidentally identified a focus of abnormal DTPA activity in the midline of the abdomen, which corresponded to lumbar tuberculosis revealed by CT images. Subsequent pathology after the resection of the lesions was consistent with lumbar and renal tuberculosis.

The exceptional speed and biorthogonality of the inverse electron-demand Diels–Alder (IEDDA) click chemistry between 1,2,4,5-tetrazines and strained alkene dienophiles have made it promising in the realm of pretargeted imaging and therapy. During the past 10 years, the IEDDA-pretargeted strategies have been tested and have already proven capable of producing images with high tumor-to-background ratios and improving therapeutic effect. This review will focus on recent applications of click chemistry ligations in the pretargeted imaging studies of single photon emission computed tomography (SPECT), positron emission tomography (PET), and pretargeted radioimmunotherapy investigations. Additionally, the influence factors of stability, reactivity, and pharmacokinetic properties of TCO tag modified immunoconjugates and radiolabeled Tz derivatives were also summarized in this article, which should be carefully considered in the system design in order to develop a successful pretargeted methodology. We hope that this review will not only equip readers with a knowledge of pretargeted methodology based on IEDDA click chemistry but also inspire synthetic chemists and radiochemists to develop pretargeted radiopharmaceutical components in a more innovative way with various influence factors considered.

Background This study aimed to investigate the prognostic value of volumetric parameters on 18F- fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in gastric-cancer patients, according to the expression status of c-MET (MET proto-oncogene, receptor tyrosine kinase), which was previously unclear. Methods The study included 61 patients with advanced gastric cancer. Data on the baseline 18F-FDG PET/CT, clinical-pathological information, progression-free survival (PFS), and overall survival (OS) were collected. The maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of gastric tumors in situ were measured on PET/CT. The expression status of c-MET was recorded based on immunohistochemical staining. Associations between the parameters on PET/CT and patients’ survival outcomes were analyzed in relation to expression status of c-MET. Results Patients with positive c-MET expression had significantly shorter PFS (11.5 vs. 17.6 months, P = 0.039) and OS (17.0 vs. 24.3 months, P = 0.043), and had gastric tumors with a larger MTV (70.8 ± 53.11 vs. 41.1 ± 52.32, P = 0.034) and TLG (428.39 ± 442.95 vs. 205.7 ± 354.40, P = 0.039), compared with those with negative c-MET expression. However, SUVmax (9.6 ± 7.40 vs. 8.0 ± 4.91, P = 0.335) and SUVpeak (7.7 ± 5.99 vs. 6.62 ± 4.08, P = 0.438) were similar between these two patient groups. In patients with c-MET-positive tumors, MTV and TLG were independent factors in predicting patient OS after correction by distant metastasis (hazards ratio = 1.014 and 1.002, respectively; P = 0.024 and 0.027, respectively), while these associations were not significant in patients with c-MET-negative tumors. Conclusions Patients with c-MET-positive gastric cancer had higher MTV and TLG values compared to those with c-MET-negative gastric cancer. In patients with c-MET-positive gastric cancer, volumetric parameters on 18F-FDG PET/CT have prognostic value for patient overall survival.

Background PET/MR is transferring from a powerful scientific research tool to an imaging modality in clinical routine practice. Whole body PET/MR screening usually takes 30–50 minutes to finish, during which a few factors might induce patient discomfort and further cause degraded image quality. The aim of this report is to investigate the patients' perception of the imaging procedure and its correlation with image quality. Methods One hundred and twenty patients (63 males and 57 females, average age = 51.3 years, range 22–70 years) who had been diagnosed with cancer or had previous history of cancer were recruited and scanned with a simultaneous PET/MR system. A questionnaire was given to all patients retrospectively after the PET/MR scan, which has nine questions to assess patients' feeling of the scan on a Likert scale scoring system (1–5, 1 as most satisfied). All PET/MR images were also visually examined by two experts independently to evaluate the quality of the images. Six body locations were assessed and each location was evaluated also with a Likert scale scoring system (1–5, 5 as the best quality). Mann–Whitney U­test was used for statistical analysis to check if there is significant correlation between image quality and patient perceptions. Results With a total of 120 patients, 118 questionnaires were filled and returned for analysis. The patients’ characteristics were summarized in Table 4. The statistics of the patients’ perception in the questionnaire were illustrated in Tables 5–7. Statistical significant correlations were found between MR image quality and patients’ characteristics/perception. Conclusion Our results show that PET/MR scanning is generally safe and comfortable for most of the patients. Statistical analysis does not support the hypothesis that bad patient’s perception leads to degraded image quality.

Background The epidemiology and cause of ossification of the spinal ligaments (OSL) remains obscure. To date, there is no study that comprehensively evaluates the prevalence, distribution, and concomitance of each type of OSL by CT among general Chinese population. We therefore aimed to comprehensively investigate epidemiological characteristics of OSL using whole spine CT in the Chinese population and examine the factors that correlate with the presence of OSL. Methods Ossification of the posterior longitudinal ligament (OPLL), ligamentum flavum (OLF), anterior longitudinal ligament (OALL), nuchal ligament (ONL), and diffuse idiopathic skeletal hyperostosis (DISH) were evaluated from the subjects who underwent PET/CT for the purpose of cancer screening in our hospital. Prevalence, distribution, and concomitance of OSL were reviewed. Logistic regression analysis was performed to identify the risk factors of OSL. Results A total of 2000 subjects (1335 men and 665 women) were included. The prevalence rate of cervical OPLL (C-OPLL) was 4.1%, thoracic OPLL (T-OPLL) 2.25%, lumbar OPLL (L-OPLL) 0.8%, thoracic OLF (T-OLF) 37.65%, lumbar OLF (L-OLF) 1.45%, ONL 31.5%, DISH 3.85%. The most commonly involved level was C5 for C-OPLL, T1 for T-OPLL, T10 for T-OLF, and T8/9 for OALL. 21% of subjects with C-OPLL had T-OPLL, 44% of C-OPLL had T-OLF, 38% of T-OPLL had C-OPLL, 53% of T-OPLL had T-OLF, 44% of L-OPLL had T-OPLL, and 56% of L-OPLL had T-OLF. The average age of OSL-positive subjects was significantly higher than that of OSL-negative subjects. The results of the multiple regression analysis revealed that males had a strong association with DISH (odds ratio, 3.15; 95% confidence interval, 1.27–7.78; P = 0.013). Conclusion The prevalence of OSL in the Chinese was revealed. Tandem ossification is not uncommon in people with OSL. There is a high incidence of multiple-regional OPLL in the whole spine. Approximately half of the subjects with OPLL coexist with T-OLF. For patients with clinical symptoms induced by OPLL, thorough evaluation of whole spine using CT is recommended.

Within the EXPLORER Consortium, the construction of the world’s first total-body PET/CT scanner has recently been completed. The 194-cm axial field of view of the EXPLORER PET/CT scanner is sufficient to cover, for the first time, the entire human adult body in a single acquisition in more than 99% of the population and allows total-body pharmacokinetic studies with frame durations as short as 1 s. The large increase in sensitivity arising from total-body coverage as well as increased solid angle for detection at any point within the body allows whole-body (18)F-FDG PET studies to be acquired with unprecedented count density, improving the signal-to-noise ratio of the resulting images. Alternatively, the sensitivity gain can be used to acquire diagnostic PET images with very small amounts of activity in the field of view (25 MBq, 0.7 mCi or less), with very short acquisition times (∼1 min or less) or at later time points after the tracer’s administration. We report here on the first human imaging studies on the EXPLORER scanner using a range of different protocols that provide initial evidence in support of these claims. These case studies provide the foundation for future carefully controlled trials to quantitatively evaluate the improvements possible through total-body PET imaging.

Parametric imaging has been shown to provide better quantitation physiologically compared with SUV imaging in PET. With the increased sensitivity from a recently developed total-body PET scanner, whole-body scans with higher temporal resolution become possible for dynamic analysis and parametric imaging. In this paper, we focus on deriving the parameter k1 using compartmental modeling, and on developing a method to acquire whole-body FDG-PET parametric images using only the first 90 seconds of the post-injection scan data with the total-body PET system. Dynamic projections were acquired with a time interval of 1 second for the first 30 seconds and 2 seconds for the following minute. Image-derived input functions were acquired from the reconstructed dynamic sequences in the ascending aorta. The one-tissue compartment model with the total of 4 parameters (k1, k2, blood fraction, delay time) was used. A maximum-likelihood based estimation method was developed with the 1-tissue compartment model solution. The accuracy of the acquired parameters was compared with the ones estimated using a 2-tissue irreversible model with 1-hour long data. All four parametric images were successfully calculated using data from two volunteers. By comparing the time-activity-curves acquired from the volume of interests, it was shown that the parameters estimated using our method were able to predict the time-activity curves of the early dynamics of FDG in different organs. The time delay effects for different organs were also clearly visible in the reconstructed time delay image with delay variations as large as 40 seconds. The estimated parameters using both 90 seconds data and 1-hour long data were in good agreement for k1 and blood fraction, while a large difference of k2 was found between the 90 seconds and 1-hour data, suggesting k2 can’t be reliably estimated from the 90 second scan. We have shown that with the use of total-body PET and the increased sensitivity, it is possible to estimate parametric images based on the very early dynamics following FDG injection. The estimated k1 could potentially be used clinically as an indicator for identifying abnormalities.

PET image quality is influenced by the patient size according to the current guideline. The study aimed to propose an optimized dose regimen to yield a constant image quality independent of patient habitus to meet the clinical needs.A first patient cohort of 78 consecutive oncological patients (59.7 ± 13.7 years) who underwent a total-body PET/CT scan were retrospectively enrolled to develop the regimen. The patients were randomly distributed in four body mass index (BMI) groups according to the World Health Organization (WHO) criteria. The liver SNR (signal-to-noise ratio, SNRThe linear fit showed SNRThe study proposed a quadratic relation between the

To investigate the performance of short-time dynamic imaging in quantifying kinetic metrics of 2-[Dynamic total-body positron emission tomography (PET) imaging was performed in 11 healthy volunteers for 75 min. The data were divided into 30-, 45- and 75-min groups. Nonlinear regression (NLR) generated constant rates (kThe 45- and 75-min groups were similar in NLR-based kinetic metrics. The relative difference ranges were as follows: kDynamic imaging using a high-sensitivity total-body PET scanner for a shorter time of 45 min could achieve relevant kinetic metrics of

The aim of the study was to determine a faster PET acquisition protocol for a total-body PET/CT scanner by assessing the image quality that is equivalent to a conventional digital PET/CT scanner from both a phantom and a clinical perspective.A phantom study using a NEMA/IEC NU-2 body phantom was first performed in both a total-body PET/CT (uEXPLORER) and a routine digital PET/CT (uMI 780), with a hot sphere to background activity concentration ratio of 4:1. The contrast recovery coefficient (CRC), background variability (BV), and recovery coefficient (RC: RCIn the phantom study, CRC, BV, RCThis study showed that a fast PET protocol with a 30-45-s acquisition time in the total-body uEXPLORER PET/CT can provide an equivalent image quality as the conventional digital uMI 780 PET/CT with longer clinical acquisition settings.

To evaluate the prognostic value of bone marrow (BM) imaging pattern and other imaging findings assessed by 18F-FDG PET-CT in multiple myeloma(MM) and to find out the image interpretation cut-off to define different BM tracer uptake pattern. We retrospectively studied PET-CT examinations and clinical data of 100 healthy individuals and 172 newly diagnosed MM patients. A BM uptake > liver SUVmean was selected as the positivity cut-off of pathological uptake in BM after comparing BM uptake in normal control and MM patients. With this interpretation cut-off, we defined the BM FDG uptake pattern as four types: normal, focal, diffuse, and mixed. The clinical correlation and prognostic value of BM uptake pattern were evaluated. The findings were validated in an independent prospective cohort with 72 MM patients. In MM cohort, 34.9% patients had focal BM uptake pattern, 3.5% had diffuse pattern, 38.4% had mixed pattern, and 23.3% had normal BM uptake. Diffuse/mixed pattern was correlated with clinical and imaging parameters indicating high tumor burden, and inferior progression free survival (PFS; 3-year-PFS 26.8%) and overall survival (OS; 3-year-OS 50.6%). BM uptake pattern was an independent prognostic factor and diffuse/mixed pattern was associated with inferior OS (P = 0.037, HR 7.16) and PFS (P = 0.015, HR 7.77). The prognostic value of BM uptake pattern was also confirmed in validation set. We propose an FDG uptake higher than liver as the positivity cut-off to discriminate between physiological and pathological uptake in BM and defined four BM FDG uptake pattern. BM FDG uptake pattern is a reliable prognostic predictor of MM.

SNA001 is a novel recombinant human thyroid stimulating hormone (rhTSH). rhTSH has long been approved in several countries to facilitate monitoring and ablation of thyroid carcinoma without hypothyroidism caused by thyroid hormone withdrawal (THW). To assess the safety, tolerance, pharmacokinetics and pharmacodynamics properties of SNA001, the two-period (SNA001 period and THW period), dose-ascending study in well-differentiated thyroid cancer (DTC) patients was designed.Three doses (0.45 mg, 0.9 mg, and 1.35 mg) of SNA001 were intramuscularly injected, twice in the SNA001 period to stimulate iodine-131 uptake and thyroglobulin (Tg) release. Twenty-four hours after the last dose of SNA001, iodine-131 (111~185MBq) was administrated, followed by whole-body scan (WBS) 48 hours later. THW period began just after SNA001 washout and lasted for about 3~6 weeks. When TSH level was above 30 mU/L, iodine-131 (111~185MBq) was administrated, followed by a WBS and Tg detection 48 hours later.Twenty-four DTC patients after thyroidectomy were enrolled, mean peak concentrations of SNA001 in 0.45 mg, 0.9 mg, 1.35 mg groups were 18.5, 26.7, and 37.0 ng/mL (about 244.7, 354.2 and 489.6 mU/L) respectively, within 28~32 hours after first dose of SNA001. SNA001 was metabolized in a dose-dependent manner. The results of WBS and Tg release in the SNA001 period were compared with those in THW period. Compared to Tg level in baseline, the Tg levels in SNA001 and THW periods were increased, with 78% of subjects showing higher Tg levels in the THW period. 100% of the patients had concordant qualitative results of the scans within two periods in three groups. Symptoms of hypothyroidism were relieved in the SNA001 period compared with THW period, though there was no significant difference in most of the scale scores. There were no serious adverse events related to SNA001, the most common adverse event were gastrointestinal symptoms, of mild and transient nature.Thus, SNA001 promises to be a safe and effective method to stimulate iodine-131 uptake and Tg secretion during monitoring and ablation for DTC without the disadvantages of incidental hypothyroidism.

The present study aimed to evaluate the feasibility of ultra-low

To investigate the feasibility of ultra-low-activity total-body positron emission tomography (PET) dynamic imaging for quantifying kinetic metrics of 2-[Dynamic total-body PET imaging was performed in 20 healthy volunteers, with eight using full activity (3.7 MBq/kg) ofAll constant rates, corresponding CoVs, and image contrast in different organs were comparable with none significant differences between full- and ultra-low-activity groups. PET images in the ultra-low-activity group generated significantly lower effective radiation dose (median, 0.419 vs. 4.886 mSv, P 0.001), reduced prompt counts (median, 2.79 vs. 55.68 billion, P 0.001), and smaller data size (median, 71.11 vs. 723.18 GB, P 0.001).Total-body dynamic PET imaging using 10× reduction of injected activity could achieve relevant kinetic metrics of

"The initial experience of using total-body PET/computed tomography (CT) (uExplorer) in Zhongshan Hospital, Fudan University, is described. Compared with conventional PET/CT, total-body PET/CT imaging provides more comprehensive information for evaluation of disease. Using fludeoxyglucose F 18, regular-dose (3.7 MBq/kg), low-dose (1.85 MBq/kg), or extra low-dose (0.37 MBq/kg) scanning, as well as high-quality imaging, protocols were used in clinical practice according to the situation. Dynamic studies were also used to assess tumor biological characteristics or for radiotracer angiography."

We report a rare case of pancreatic collision tumor of solid pseudopapillary tumor and neuroendocrine tumor in a 43-year-old woman. A pancreatic mass was found by abdominal ultrasound. A mainly cystic mass with solid component progressive enhancement was revealed using abdominal enhanced CT. Staging 18F-FDG PET/CT demonstrated a pancreatic tail mass with an increased uneven 18F-FDG uptake. Distal pancreatectomy was performed. Postoperatively, the mass was diagnosed as pancreatic collision tumor of solid pseudopapillary tumor and neuroendocrine tumor.

PURPOSE The aim of this study was to explore the value of skeletal standardized uptake value (SUV) obtained by quantitative single-photon emission computed tomography-computed tomography (SPECT/CT) in differential diagnosis of bone metastases from benign lesions. MATERIALS AND METHODS Retrospective analysis has been conducted to 51 patients with extraskeletal malignant tumors who underwent whole-body bone scan with quantitative SPECT/CT imaging, and there are no more than three hotspots that were visually detected in the SPECT/CT imaging range. Fifty-one patients were enrolled, including 28 men and 23 women with an average age of 58.8 ± 9.5 (37-77) years. A total of 88 hotspots, including 40 benign lesions and 48 metastatic lesions, and corresponding normal sites were obtained. The region of interest (ROI) of the hotspots was sketched. The ROI of the normal bone of the spinal vertebral body adjacent to the lesions or normal bone of the symmetric side of the lesions of other locations was delineated to obtain the maximum SUV (SUVmax) and the average SUV (SUVave). RESULTS The SUVmax value of all lesions was 20.73 ± 14.01 (3.90-92.61), and the SUVmax value of the corresponding normal parts was 5.88 ± 2.36 (2.08-12.52). The difference between the two groups was statistically significant (t = 10.343, P

Objectives The aim of the study was to summarize the features of immunoglobulin G4-related lung disease (IgG4-RLD) on fluorine 18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT). Methods In this retrospective case series, 12 consecutive patients (9 men and 3 women, mean age 55.4 ± 13.7 years) with IgG4-RLD were included. The clinicopathological information and features of F-FDG PET/CT imaging were analyzed. Results Six (50%) patients had pulmonary involvement alone and six (50%) patients had extrapulmonary involvement with intense F-FDG uptake. Pulmonary manifestations included mass (25%, 3/12), solid nodule (solitary 25%, 3/12; multiple 50%, 6/12), multiple ground-glass opacities (GGOs) (50%, 6/12), thickening of alveolar interstitium (50%, 6/12), and thickening of bronchovascular bundle (33.3%, 4/12). The maximum standardized uptake value (SUVmax) of the solid nodules and masses, multiple GGOs, bronchovascular bundle and the thickening of septa was 4.0 ± 2.5, 2.3 ± 1.8, 1.4 ± 0.6, and 0.9 ± 0.5, respectively. The SUVmax statistically significant linear association with the diameter of masses or solid nodules (P value = 0.03), but no significant inverse linear association (P value = 0.06) with the concentration of serum IgG4 concentration. Conclusions The image patterns of IgG4-RLD on F-FDG PET/CT are varying. Multiple pulmonary manifestations or multiple organ involvement, especially in combination with elevated levels of serum IgG and IgG4, may help to make the diagnosis. A potential major application of PET-CT would be evaluation of response to treatment, and the impact of PET/CT on IgG4-RLD management is worth investigating further in the future.

Considering the few reported cardiac masses, PET/CT in the imaging workup of cardiac masses is not well established. This retrospective study analyzed the role ofFifty-nine patients with newly diagnosed cardiac/pericardial masses who underwent PET/CT and transthoracic echocardiography (TTE) were recruited. Echocardiographic and PET/CT characteristics were evaluated for predictive value in differentiating malignant and non-malignant lesions using histologic confirmation as the gold standard. The McNemar test was used to test the differences in sensitivity between PET/CT and TTE.PET/CT was an effective additional image modality in patients with suspected malignant cardiac mass for further confirmation and to screen for potential metastasis.

The aim of this study was to evaluate the role of dual-time pointDual-time point FDG PET/CT findings, including early phase whole-body scanning and abdominal delayed phased performed 1 and 2 h after radiotracer injection, respectively, were retrospective reviewed in 69 patients conformed HCCA by histology. PET/CT was evaluated based on visual interpretation and the semiquantitative index of SUVmax and tumor-to-normal liver tissue ratio (TNR) for both early and delayed images.For all 69 HCCA patients, the mean SUVmax of the lesion and TNR in delayed phase was significantly higher than that in early phase (6.1 ± 4.7, 2.2 ± 1.7, vs 5.1 ± 3.4, 1.6 ± 1.1; P 0.001). The sensitivity and accuracy value of detection primary lesions was 69.6% and 70% in early phase vs 76.8% and 76.8% in delay phase, respectively. There was a significant correlation between lesion SUVmax and Ki67 index in both dual-time imaging (r = 0.462, P 0.001 in early phase vs r = 0.47, P 0.001 in delay phase). The sensitivity, specificity and accuracy value of metastatic lymph nodes prediction was 50%, 67.3% and 71% in early phase vs 62.5%, 73.3% and 76.8% in delayed phase, respectively. The sensitivity, specificity and accuracy of FDG PET/CT in detecting distant metastasis in our study was 75%, 100% and 97.1%. There was no difference of predicting distant metastasis between early phase and delayed phase.Delayed phase in dual-time point

Previously, we successfully developed a pretargeted imaging strategy (atezolizumab-TCO/[99mTc]HYNIC-PEG11-Tz) for evaluating programmed cell death ligand-1 (PD-L1) expression in xenograft mice. However, the surplus unclicked [99mTc]HYNIC-PEG11-Tz is cleared somewhat sluggishly through the intestines, which is not ideal for colorectal cancer (CRC) imaging. To shift the excretion of the Tz-radioligand to the renal system, we developed a novel Tz-radioligand by adding a polypeptide linker between HYNIC and PEG11. Pretargeted molecular probes [99mTc]HYNIC-polypeptide-PEG11-Tz and cetuximab-TCO were synthesized. [99mTc]HYNIC-polypeptide-PEG11-Tz was evaluated for in vitro stability and in vivo blood pharmacokinetics. In vitro ligation reactivity of [99mTc]HYNIC-polypeptide-PEG11-Tz towards cetuximab-TCO was also tested. Biodistribution assay and imaging of [99mTc]HYNIC-polypeptide-PEG11-Tz were performed to observe its excretion pathway. Pretargeted biodistribution was measured at three different accumulation intervals to determine the optimal pretargeted interval time. Pretargeted (cetuximab-TCO 48 h/[99mTc]HYNIC-PEG11-Tz 6 h) and (cetuximab-TCO 48 h/[99mTc]HYNIC-Polypeptide-PEG11-Tz 6 h) imagings were compared to examine the effect of the excretion pathway on tumor imaging. [99mTc]HYNIC-polypeptide-PEG11-Tz showed favorable in vitro stability and rapid blood clearance in mice. SEC-HPLC revealed almost complete reaction between cetuximab-TCO and [99mTc]HYNIC-polypeptide-PEG11-Tz in vitro, with the 8:1 Tz-to-mAb reaction providing a conversion yield of 87.83 ± 3.27 %. Biodistribution and imaging analyses showed that the Tz-radioligand was cleared through the kidneys. After 24, 48, and 72 h of accumulation in HCT116 tumor, the tumor-to-blood ratio of cetuximab-TCO was 0.83 ± 0.13, 1.40 ± 0.31, and 1.15 ± 0.21, respectively. Both pretargeted (cetuximab-TCO 48 h/[99mTc]HYNIC-PEG11-Tz 6 h) and (cetuximab-TCO 48 h/[99mTc]HYNIC-polypeptide-PEG11-Tz 6 h) clearly delineated HCT116 tumor. Pretargeted imaging strategy using cetuximab-TCO/[99mTc]HYNIC-polypeptide-PEG11-Tz could be used for diagnosing CRC, as the surplus unclicked [99mTc]HYNIC-polypeptide-PEG11-Tz was cleared through the urinary system, leading to low abdominal uptake background. Our novel pretargeted imaging strategy (cetuximab-TCO/[99mTc]HYNIC-polypeptide-PEG11-Tz) was useful for imaging CRC, broadening the application scope of pretargeted imaging strategy. The pretargeted imaging strategy clearly delineated HCT116 tumor, showing that its use could be extended to selection of internalizing antibodies.

To investigate the kinetic metrics of 2-[Dynamic TB-PET was performed for nine healthy volunteers. Time-to-activity curves (TACs) were obtained by drawing regions of interest in the organs. A two-tissue compartment model was fitted for each tissue TAC. Constant rates, including kConstant rates and MRFDG varied significantly among organs and subjects, but not among sides or sub-regions within an organ. The mean kThe kinetic rates and MRFDG significantly differed among organs. The kinetic metrics of FDG parameters in normal organs can serve as a reference for future dynamic PET imaging and research.

In this paper, we aimed to evaluate the positron emission tomography (PET) performance of, to the best of our knowledge, the third commercially available whole-body integrated PET/magnetic resonance (MR) system. The PET system performance was measured following the NEMA standards with and without simultaneous MR operation. PET spatial resolution, sensitivity, scatter fraction, count-rate performance, accuracy of count losses and random corrections, image quality, and time-of-flight (TOF) resolution were quantitatively evaluated. Clinical scans were acquired at the PET/MR system and compared with images acquired at a PET/CT with the same digital detector technology. Measurement results of essential PET performance were reported in the form of MR idle (MR pulsing). The axial, radial, and tangential spatial resolutions were measured as 2.72 mm (2.73 mm), 2.86 mm (2.85 mm), and 2.81 mm (2.82 mm) FWHM, respectively, at 1 cm radial offset. The NECR peak was measured as 129.2 kcps (129.5 kcps) at 14.7 kBq mL−1 (14.2 kBq mL−1). The scatter fraction at NECR peak was 37.9% (36.5%), and the maximum slice error below NECR was 4.1% (4.5%). Contrast recovery coefficients ranged from 51.8% (52.3%) for 10 mm hot sphere to 87.3% (87.2%) for 37 mm cold sphere. TOF resolution at 5.3 kBq mL−1 was measured at 535 ps (540 ps). With point source, TOF was measured to be 474 ps (485 ps). Clinical scans revealed similar image quality from the PET/MR and the comparative PET/CT system. The PET performance of the newly introduced integrated PET/MR system is not significantly affected by the simultaneous operation of an MR sequence (2-point DIXON sequence). Measurement results demonstrate comparable performance with other state-of-the-art PET/MR systems. The clinical benefits of high spatial resolution and long axial coverage remain to be further evaluated in specific clinical imaging applications.

Aim Radium-223, a targeted alpha therapy, is approved widely for the treatment of patients with metastatic castrate-resistant prostate cancer, based on a pivotal phase 3 study in predominantly white patients. We investigated the efficacy and safety of radium-223 in Asian patients with castrate-resistant prostate cancer and metastatic bone disease. Methods This multicenter, prospective, single-arm, open-label phase 3 trial evaluated the efficacy and safety of the standard radium-223 regimen (55 kBq/kg every 4 weeks for six cycles) in patients from Asian countries. The primary endpoints were the safety and overall survival. Results A total of 226 patients were enrolled and received at least one dose of radium-223. Median overall survival was 14.0 months (95% confidence interval [CI], 11.2-17.4). Median time to total alkaline phosphatase and prostate-specific antigen progression were 7.5 (95% CI, 6.8-7.7) and 3.6 (95% CI, 3.1-3.7) months, respectively. Median skeletal-related event-free survival was 26.0 months (95% CI, 12.6-not reached). Grade ≥3 treatment-emergent adverse events were reported in 103 (46%) of 226 patients, with anemia being the most common event (34 [15%] patients). Grade ≥3 drug-related treatment-emergent adverse events occurred in 39 (17%) of 226 patients. Serious treatment-emergent adverse events were reported in 65 (29%) of 226 patients. Seven (3%) patients had an adverse event leading to death; none were considered to be related to radium-223. Conclusion The results of this study support the use of the standard radium-223 regimen for the treatment of Asian patients with castrate-resistant prostate cancer and symptomatic bone metastases.

The aim of this study is to investigate the value of pre-treatmentA total of 34 patients who underwentThe AUCs for T-SUVmax, T/L, and T/B in predicting the pathological grade of tumors were 0.820, 0.784, and 0.806, respectively. Alternatively, the AUCs for T-SUVmax, T/L, and T/B in predicting the recurrence after LT were 0.865, 0.899, and 0.931, respectively. The individual cutoff values were 5.0, 1.7, and 2.2, corresponding to a predication accuracy of 88.2%, 85.3%, and 88.2%, respectively. In addition, the AUCs for T/B in predicting microvascular invasion (mVI) and liver capsular invasion (LCI) were 0.825 and 0.788, respectively.The pre-treatment

The present study aimed to investigate the prognostic value of intra-tumor metabolic heterogeneity on 2-[18F] Fluoro-2-deoxy-D-glucose (

c-MET-positive NSCLC is an important subtype accounting for about 5%~22% of lung cancer. NSCLC patients with activating c-MET are intensively sensitive to c-MET selective receptor tyrosine kinase (RTK) inhibitors, so we aimed to develop a specific PET probe targeting to c-MET-positive NSCLC for potential patients screened by PET/CT. Herein, PET tracer

Extended lymph node involvement could indicate limited survival benefit from neoadjuvant chemoradiotherapy with surgery in resectable locally advanced esophageal cancer. However, the threshold of node involvement is unclear.We retrospectively measured and calculated metabolic parameters derived fromA total of 67 patients were enrolled in the study. The MTVp with thresholds as 3.0, 3.5, 4.0, 4.5 and 5.0 were significantly correlated with clinical T categories (Spearman's rank correlation coefficient, all P 0.0001) and clinical tumor length categories (Spearman's rank correlation coefficient, all P ≤ 0.005). However, the MTVn were marginally correlated with clinical lymph node categories (P = 0.023). Among the 31 (31/67, 46.3%) patients with MTVn as 0 (R-MTB as 100.00%), 5 (5/5, 100.0%) were initially restaged as cLym- (MTVn as 0, R-MTB as 100.00%), while 26 (26/62, 41.9%) were initially restaged as cLym + (MTVn 0, R-MTB 100.00%). After nCRT, 43 (64.2%) patients achieved ypN0. The univariate and multivariate regression revealed that R-MTB (≤ 106.00% vs. 106.00%) was an independent factor associated with ypN + status (OR 0.093, 95%CI 0.023-0.378, P = 0.001).The preliminary study revealed a great heterogeneity in clinical lymph node categories in esophageal cancer. It suggested that R-MTB was significantly associated with ypN status after neoadjuvant chemoradiotherapy in locally advanced esophageal cancer. The findings with the indications needed to be further studied in a prospective study with a large patient cohort.

Hepatic epithelioid hemangioendothelioma (HEHE) is a low-to-intermediate-grade malignant mesenchymal tumor. The diagnostic and prognostic values of 2-[18F] fluoro-2-deoxy-D-glucose (

This retrospective study investigated the performance of whole-body bone scintigraphy combined with SPECT/CT and established a grading diagnostic criterion for bone metastases. We summarized signs of whole-body bone imaging combined with SPECT in nuclear medicine and CT signs of corresponding parts. Then we established a diagnostic criterion for bone metastases by using whole-body bone scintigraphy combined with local SPECT/CT. The criterion is classified into five grades. 120 patients with a total of 141 lesions underwent whole-body bone scintigraphy and SPECT/CT. Two reviewers read the images according to the diagnostic criterion. With pathological diagnosis as the “gold standard”, the diagnostic efficacy for bone metastases and the diagnostic agreement between the two reviewers were analyzed to validate the feasibility of the criterion. Diagnostic effectiveness was expressed in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. The diagnostic accuracy of the two reviewers was 90.1% and 92.9% respectively, sensitivity was both 100%, specificity was 41.7% and 58.3%, positive predictive value was 89.3% and 92.1%, and negative predictive value was both 100%. The kappa value of the diagnostic tests performed by the two reviewers on whole-body bone scintigraphy combined with SPECT/CT was 0.919 (P

The aim of this study was to investigate the correlation of coronary flow reserve (CFR) assessed by rest/stress myocardial perfusion imaging with dynamic single-photon emission computed tomography (SPECT) with intracoronary pressure-derived fractional flow reserve (FFR) in patients with single-vessel coronary artery disease (CAD). Patients with suspected or known stable CAD who were referred for invasive coronary angiography were prospectively enrolled. Both invasive FFR and SPECT were performed in subjects with single-vessel intermediate coronary stenosis. A cutoff value of

Deep sternal wound infection (DSWI) is a severe complication in patients after open heart surgery (OHS). But there is a lack of appropriate imaging tool to detect the infection sites, which may lead to incomplete debridement. The present study aims to investigate the value of (18)F‐fluorodeoxyglucose positron emission tomography/computed tomography ((18)F‐FDG PET/CT) in comparison with CT scan in diagnosing and localising DSWI. A total of 102 patients with DSWI after OHS were retrospectively collected from January 2012 to December 2017 in our hospital. All the patients had surgical debridements for DSWI with pretreatment imaging of either (18)F‐FDG PET/CT or CT scan. The sensitivity, specificity, and accuracy of localising infection sites were compared between PET/CT and CT groups, with surgical, microbiological, and histopathological findings as the gold standard. The length of hospital stays and the rate of recurrence were also compared. Ten patients in the PET/CT group had a follow‐up PET/CT scan after debridement, and the correlations between the changes of PET/CT findings and surgical outcomes were analysed. (18)F‐FDG PET/CT is more accurate than CT in diagnosing and localising DSWI after OHS, which leads to a more successful surgical debridement with a lower rate of recurrence and a shorter length of hospital stay. In addition, follow‐up PET/CT after debridement could evaluate the treatment effect.

A 194-cm-long total-body positron emission tomography/computed tomography (PET/CT) scanner (uEXPLORER), has been constructed to offer a transformative platform for human radiotracer imaging in clinical research and healthcare. Its total-body coverage and exceptional sensitivity provide opportunities for innovative studies of physiology, biochemistry, and pharmacology. The objective of this study is to develop a method to perform ultrahigh (100 ms) temporal resolution dynamic PET imaging by combining advanced dynamic image reconstruction paradigms with the uEXPLORER scanner. We aim to capture the fast dynamics of initial radiotracer distribution, as well as cardiac motion, in the human body. The results show that we can visualize radiotracer transport in the body on timescales of 100 ms and obtain motion-frozen images with superior image quality compared to conventional methods. The proposed method has applications in studying fast tracer dynamics, such as blood flow and the dynamic response to neural modulation, as well as performing real-time motion tracking (e.g., cardiac and respiratory motion, and gross body motion) without any external monitoring device (e.g., electrocardiogram, breathing belt, or optical trackers).

To investigate the added value of dual-time-point 18F-FDG PET/CT imaging in the diagnosis of colorectal cancer liver metastases (CRLM). One hundred and eight patients with CRLM preoperatively underwent a dual-time-point 18F-FDG PET/CT scan. All hepatic lesions were diagnosed by histopathology. The diagnostic sensitivity of 18F-FDG PET/CT for CRLM was calculated on early scan and delayed scan, respectively. The McNemar test was used to test the differences of the sensitivity and the specificity between early scan and delayed scan. On a per-patient basis, no significant difference in sensitivity was found between early scan and delayed scan (92.93% vs. 96.97%, P = 0.125). The per-patient specificity of early and delayed scans was 77.78%. On a per-lesion basis, overall sensitivity of delayed scan was significantly higher than that of early scan (83.49% vs. 76.61%, P 10 mm, there was no significant difference in sensitivity between early and delayed scans (92.73% vs. 95.15%, P = 0.125). Of the detected 182 liver metastatic lesions on delayed scan, the SUVmax on delayed scan was significantly higher than that on early scan (12.13 ± 7.13 vs. 9.16 ± 4.74, P

Background and objectives To improve lung nodule classification efficiency, we propose a lung nodule CT image characterization method. We propose a multi-directional feature extraction method to effectively represent nodules of different risk levels. The proposed feature combined with pattern recognition model to classify lung adenocarcinomas risk to four categories: Atypical Adenomatous Hyperplasia (AAH), Adenocarcinoma In Situ (AIS), Minimally Invasive Adenocarcinoma (MIA), and Invasive Adenocarcinoma (IA). Methods First, we constructed the reference map using an integral image and labelled this map using a K-means approach. The density distribution map of the lung nodule image was generated after scanning all pixels in the nodule image. An exponential function was designed to weight the angular histogram for each component of the distribution map, and the features of the image were described. Then, quantitative measurement was performed using a Random Forest classifier. The evaluation data were obtained from the LIDC-IDRI database and the CT database which provided by Shanghai Zhongshan hospital (ZSDB). In the LIDC-IDRI, the nodules are categorized into three configurations with five ranks of malignancy (“1” to “5”). In the ZSDB, the nodule categories are AAH, AIS, MIA, and IA. Results The average of Student's t-test p-values were less than 0.02. The AUCs for the LIDC-IDRI database were 0.9568, 0.9320, and 0.8288 for Configurations 1, 2, and 3, respectively. The AUCs for the ZSDB were 0.9771, 0.9917, 0.9590, and 0.9971 for AAH, AIS, MIA and IA, respectively. Conclusion The experimental results demonstrate that the proposed method outperforms the state-of-the-art and is robust for different lung CT image datasets.