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Identification of primary tumors and metastasis sites is an essential step in cancer diagnostics and the following treatment. Positron emission tomography-computed tomography (PET/CT) is one of the most reliable methods for scanning the whole organism for malignancies. In this work, we synthesized an 11C-labeled oligonucleotide primer and hybridized it to an anti-cancer DNA aptamer. The 11C-aptamer was applied for in vivo imaging of Ehrlich ascites carcinoma and its metastases in mice using PET/CT. The imaging experiments with the 11C-aptamer determined very small primary and secondary tumors of 3 mm2 and less. We also compared 11C imaging with the standard radiotracer, 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG), and found better selectivity of the 11C-aptamer to metastatic lesions in the metabolically active organs than 18F-FDG. 11C radionuclide with an ultra-short (20.38 min) half-life is considered safest for PET/CT imaging and does not cause false-positive results in heart imaging. Its combination with aptamers gives us high-specificity and high-contrast imaging of cancer cells and can be applied for PET/CT-guided drug delivery in cancer therapies., Graphical abstract, In this work, a DNA aptamer was labeled with 11C radionuclide and applied for cancer imaging in mice using positron emission tomography-computed tomography (PET/CT). The imaging experiments with the 11C-aptamer determined very small primary tumors and metastases of 3 mm2 and less.

Aims To evaluate whether biomarkers derived from fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) performed prior to (prePET) and during the third week (interim PET; iPET) of radiotherapy can predict treatment outcomes in human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPC). Materials and methods This retrospective analysis included 46 patients with newly diagnosed OPC treated with definitive (chemo)radiation and all patients had confirmed positive HPV status (HPV+OPC) based on p16 immunohistochemistry. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV) and total lesional glycolysis (TLG) of primary, index node (node with the highest TLG) and total lymph nodes and their median percentage (≥50%) reductions in iPET were analysed, and correlated with 5-year Kaplan–Meier and multivariable analyses (smoking, T4, N2b-3 and AJCC stage IV), including local failure-free survival, regional failure-free survival, locoregional failure-free survival (LRFFS), distant metastatic failure-free survival (DMFFS), disease-free survival (DFS) and overall survival. Results There was no association of outcomes with prePET parameters observed on multivariate analysis. A complete metabolic response of primary tumour was seen in 13 patients; the negative predictive value for local failure was 100%. More than a 50% reduction in total nodal MTV provided the best predictor of outcomes, including LRFFS (88% versus 47.1%, P = 0.006, hazard ratio = 0.153) and DFS (78.2% versus 41.2%, P = 0.01, hazard ratio = 0.234). More than a 50% reduction in index node TLG was inversely related to DMFFS: a better nodal response was associated with a higher incidence of distant metastatic failure (66.7% versus 100%, P = 0.009, hazard ratio = 3.0). Conclusion The reduction (≥50%) of volumetric nodal metabolic burden can potentially identify a subgroup of HPV+OPC patients at low risk of locoregional failure but inversely at higher risk of distant metastatic failure and may have a role in individualised adaptive radiotherapy and systemic therapy.

Pulmonary artery intimal sarcoma (PAIS) is a rare tumor with an incidence of 0.001%–0.03% that usually grows along artery walls and absorbs fluorodeoxyglucose. It is difficult to distinguish PAIS from pulmonary thromboembolism due to the similarities of their symptoms. Therefore, contrast-enhanced computed tomography and positron emission tomography-computed tomography (PET-CT) should be used to establish a correct diagnosis. Here we report a case of an extremely rare type of PAIS, pedunculated PAIS, which could not be visualized on PET-CT. Histological features of a tumor with a low accumulation of fluorodeoxyglucose revealed low-cellularity and necrotizing background. Multimodal imaging was useful to diagnose PET-CT negative PAIS accurately.

OBJECTIVES It would be a medically important advance if durable and focal neuromodulation of the brain could be delivered noninvasively and without ablation. This ongoing study seeks to elucidate the effects of precisely delivered ionizing radiation upon focal brain metabolism and the corresponding cellular integrity at that target. We hypothesize that focally delivered ionizing radiation to the brain can yield focal metabolic changes without lesioning the brain in the process. MATERIALS AND METHODS We used stereotactic radiosurgery to deliver doses from 10 Gy to 120 Gy to the left primary motor cortex (M1) of Lee Sung miniature pigs (n = 8). One additional animal served as a nonirradiated control. We used positron emission tomography-computed tomography (PET-CT) to quantify radiation dose-dependent effects by calculating the ratio of standard uptake values (SUV) of 2-deoxy-2-[18 F]-fluoro-D-glucose (18 F-FDG) between the radiated (left) and irradiated (right) hemispheres across nine months. RESULTS We found that the FDG-PET SUV ratio at the targeted M1 was significantly lowered from the pre-radiation baseline measurements for animals receiving 60 Gy or higher, with the effect persisting at nine months after radiosurgery. Only at 120 Gy was a lesion suggesting ablation visible at the M1 target. Animals treated at 60-100 Gy showed a reduced signal in the absence of an identifiable lesion, a result consistent with the occurrence of neuromodulation. CONCLUSION Focal, noninvasive, and durable changes in brain activity can be induced without a magnetic resonance imaging (MRI)-visible lesion, a result that may be consistent with the occurrence of neuromodulation. This approach may provide new venues for the investigation of neuromodulatory treatments for disorders involving dysfunctional brain circuits. Postmortem pathological analysis is needed to elucidate whether there have been morphological changes not detected by MRI.

There is a lack of consensus regarding the management of post-chemotherapy residual mass in classical seminoma. The use of fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) may aid the detection of residual masses harbouring viable disease and help to tailor therapy. The aim of this study was to evaluate if PET-CT could identify patients who will benefit from locoregional radiotherapy.This ethics-approved study included patients with advanced classical seminoma primarily treated with standard platinum-based first-line chemotherapy. Patients were either observed or given adjuvant radiotherapy based on the clinician's preference and followed up. For this study, patients were stratified into two groups based on FDG PET-CT residual nodal maximum standardised uptake value (SUVmax): low risk (SUVmax3) and high risk (SUVmax ≥3). Further subgroup analysis was carried out for patients with residual nodal size ≥3 cm and SUVmax ≥3, and this was considered as the very high risk group. The diagnostic accuracy of FDG PET-CT was assessed and survival was compared between the different groups.Sixty-nine patients were included in the study: 48 patients were observed and 21 received radiotherapy. The low and high risk groups contained 50.7% and 49.3% of the patients, respectively. The very high risk subgroup had 24 patients. At a median follow-up of 44 months, locoregional failures in the radiotherapy and observation cohorts were 0% and 30% (P = 0.059) in the very high risk subgroup and 5.8% and 29.4% (P = 0.078) in the high risk group. The positive predictive value for the very high risk and high risk groups was 30% and 17.1%, respectively. The benefit of locoregional control failed to translate into overall survival benefit.A tailored, FDG PET-based risk-adapted treatment approach can refine the management of post-chemotherapy residual masses in seminoma. In this study, with the largest cohort of advanced seminoma patients treated with radiotherapy reported to date, radiotherapy seems to benefit patients with post-chemotherapy residual mass SUVmax ≥3.

Objective The maximum standardized uptake value (SUVmax) derived by positron emission tomography-computed tomography (PET/CT) can be an index of biological tumor aggressiveness, which is assessed using noninvasive tools before the treatment of epithelial ovarian cancer (EOC). This study aimed to evaluate the prognostic value of the pretreatment SUVmax in patients with EOC. Materials and methods We reviewed the data of patients with EOC who underwent pretreatment 18F-FDG PET/CT between June 2006 and September 2016. The relationships between pretreatment SUVmax and histological subtypes of EOC were determined. Moreover, progression-free survival (PFS) and overall survival (OS) were evaluated according to the pretreatment SUVmax. Risk factors associated with progression or death were also analyzed. Results Of 148 patients, 66 (44.6%), 11 (7.4%), 34 (23.0%), 19 (12.8%), 15 (10.1%), and three (2.0%) were diagnosed with high-grade serous carcinoma (HGSC), low-grade serous carcinoma (LGSC), clear cell carcinoma (CCC), endometrioid carcinoma, mucinous carcinoma, and others, respectively. The median SUVmax was marginally lower in LGSC (6.80 vs. 10.5; P = 0.059) and significantly lower in CCC (5.92 vs. 10.5; P = 0.001) than in HGSC. A high pretreatment SUVmax (≥9.30) was a prognostic factor for OS in patients with LGSC (P = 0.046). Furthermore, multivariate analysis revealed that a high SUVmax (≥5.85) was an independent prognostic factor for OS (P = 0.046) in patients with CCC. However, a high SUVmax (≥7.77) was a poor predictor of PFS and OS in patients with EOC (P = 0.156 and P = 0.158, respectively). Conclusion Our findings suggest that the pretreatment SUVmax is not only an independent predictor of survival in patients with CCC but also a significant predictor of survival in patients with LGSC.

Rationale and objectives Hybrid positron emission tomography-magnetic resonance (PET-MR) is a novel imaging technology that enables a comprehensive assessment of myocardial viability. The aim of this study was to intra-individually compare simultaneously acquired viability parameters from MRI and PET to determine complementary and redundant information. Materials and Methods Thirty-nine patients with ischemic heart disease (IHD) underwent cardiac PET-MR for myocardial viability assessment. Cardiac magnetic resonance (CMR), including late gadolinium enhancement (LGE), and PET, including a dynamic dual-tracer acquisition of [13N]ammonia ([13N]NH3)/[18F]fluorodeoxyglucose ([18F]FDG), were performed simultaneously. Allocation, extent, and transmural degree of left ventricular (LV) scars were measured from LGE. Perfusion, viability, and hibernation were assessed by PET. Results A comparison of scar location revealed six more areas of infarction on MR than on PET. Mean LV scarring by CMR was 14% (range, 2% to 42%) and 14% (range, 1% to 46%) by PET (CMR vs. PET: p = 0.9). An intra-individual comparison of scarring showed a good inter-method correlation (r = 0.7), which was also evident in the subgroup with low ejection fraction (EF) (r = 0.6). Hibernation and transmural degree of scars showed a moderate to weak correlation (r = 0.4), which was even worse in the low EF group (r = 0.1). Conclusions In patients with IHD, there was a good correlation between PET and CMR for the LV scar extent using hybrid cardiac PET-MR. The degree of transmural scarring by CMR showed no correlation to PET hibernation. Therefore, cardiac PET-MR might be a suitable tool for a comprehensive assessment of myocardial viability if used to predict response to cardiac reperfusion strategies.

Background Valid prognostic tools are needed to guide risk-adjusted treatment approaches in patients with diffuse large B-cell lymphoma (DLBCL). Methods We assessed total metabolic tumor volume (TMTV) and standardized uptake value (SUV)-based interim positron emission tomography (iPET) response in 510 patients with DLBCL participating in the positron emission tomography-guided therapy of aggressive non-Hodgkin lymphomas (PETAL) trial (NCT00554164). TMTV was analyzed with a relative (SUV41max) and a fixed thresholding method (SUV4), and iPET was evaluated using the ΔSUVmax procedure. We determined associations between TMTV and international prognostic index (IPI) factors using Welch's t-test, investigated effects of TMTV, iPET response, and the IPI factors on time to progression (TTP), progression-free survival (PFS), and overall survival (OS) by Cox regression, and estimated the outcome using Kaplan–Meier curves. Findings TMTV was associated with all IPI factors except age. Irrespective of the thresholding method used, TMTV and iPET response were correlated with TTP, PFS, and OS, and remained the only independent outcome predictors in Cox regression analysis. By dichotomizing TMTV (cut-off: 328 cm³ by SUV41max) and iPET response (cut-off: 66% SUVmax reduction), we defined three groups at different risk of treatment failure (low [57.1% of patients]: low TMTV/good iPET response; intermediate [37.8%]: high TMTV/good iPET response or low TMTV/poor iPET response; and high [5.1%]: high TMTV/poor iPET response), with corresponding 2-year probabilities of 93.8% vs. 67.3% vs. 38.5% for TTP, 90.9% vs. 62.5% vs. 29.9% for PFS, and 95.5% vs. 77.4% vs. 37.1% for OS. Interpretation The PET-based risk model proposed may help identify patients who may benefit from treatment modifications or novel approaches.

Positron-emission tomography (PET) is the imaging modality of choice in oncology. In addition, there are several indications for using PET in cardiology and neurology. The main radiotracer used is the radiolabeled glucose analog [18F] fluorodeoxyglucose ([18F] FDG). The high-energy annihilation radiation from positron emission may lead to significant radiation exposure to medical imaging professionals such as technologists and staff nurses, patients, and direct acquaintances of the patient. In this cross-sectional observational study, the effective dose to workers in the Molecular Imaging Center from patients injected with [18F] FDG is assessed. Dose rates were estimated by a calibrated, portable gamma-ray survey meter at 0.3, 0.5, 1.0, and 2.0 m from 70 patients who underwent whole body [18F] FDG PET/CT procedure immediately and 2 hours post-injection. Electronic personal dosimeters were used to determine the radiation doses per PET/CT imaging for the five staff who directly involved in handling of the injected patients. The staff includes two technologists, two staff nurses, and one medical physicist. The mean dose rates from patients after injection and standard deviation (μSv/h) for the four distances were 98.1 ± 20.0, 55.3 ± 20.0, 28.2 ± 10.0, and 10.8 ± 5.0, respectively. After 2 hours, the measurements significantly dropped to 45.7 ± 10.0, 23.6 ± 10.0, 9.9 ± 4.0, and 3.7 ± 1.0 μSv/h. The average effective dose values for a technologist from injected patients throughout the procedure of PET/CT study was 4.17 μSv per study or 5 mSv/y. This is less than the annual limit recommended by the International Commission on Radiological Protection of 20 mSv/y received in the medical imaging profession.

The double-electron capture and the electron capture with positron emission in 168Yb have been investigated for the first time at the STELLA facility of the Gran Sasso underground laboratory (Italy) measuring 371 g of highly purified ytterbium oxide placed on the end-cap of a 465 cm3 ultra-low-background high purity Germanium detector (HPGe). No gamma associated to double beta processes in 168Yb have been observed after 2074 h of data taking. This has allowed setting the half-life limits on the level of lim ⁡ T 1 / 2 ∼ 10 14 – 10 18 yr at 90% C.L. Particularly, a lower half-life limit on a possible resonant neutrinoless double-electron capture in 168Yb to the ( 2 ) − 1403.7 keV excited state of 168Er is set as T 1 / 2 ≥ 1.9 × 10 18 yr at 90% C.L. Half-life limits T 1 / 2 2 ν ( 0 ν ) ≥ 4.5 ( 4.3 ) × 10 16 yr were set on the 2 ν ( 0 ν ) 2 β − decay of 176Yb to the 2 + 84.3 keV first excited level of 176Hf.

Positron emission particle tracking (PEPT) has been shown to be useful for flow interrogation in opaque systems. In this work, a recently developed method for multiple-particle PEPT (M-PEPT) is employed for measurement of flow in a pipe at ReD = 42 600, and results are compared to direct numerical simulation (DNS) data to test the capability of M-PEPT for measurement of statistical quantities in turbulent flow. Correction for photon depth of interaction in detectors is seen to be needed and is applied. M-PEPT is shown to be capable of measuring quantities such as mean velocity and acceleration, Reynolds stress, and turbulent kinetic energy budget outside of the near-wall region. Further refinement of the technique is needed to resolve near-wall turbulence features.

Fluorine-18–labeled deoxyglucose (FDG) positron emission computed tomography (PET/CT) has emerged as the preferred modality for detecting cardiovascular inflammation [(1)][1], immunosuppressive treatment responses [(2)][2], and prognoses in patients with cardiac sarcoidosis (CS) [(1)][1]. Despite

Prostate carcinoma is the most common malignancy in men and the second cause of death by cancer in the western world. Currently, prostate carcinoma's diagnosis is achieved by transrectal ultrasound-guided biopsy (gold-standard), usually requested after an elevation of prostate specific antigen (PSA) levels or an abnormal digital rectal exam or transrectal ultrasound. Nevertheless, this diagnosis sequence sometimes presents with significant limitations. Therefore, there is a need of a diagnosis modality that improves the tumor detection rates and that offers information for its accurate staging, allowing the treatment's planning and administration. Molecular imaging by the means of positron emission tomography uses radiopharmaceuticals labeled with positron-emitting radioisotopes to detect metabolic changes that might be suggestive of cancer tissue. Recently, this technique has suffered a huge dynamic development, and researchers have been working on novel radiotracers agents to improve accuracy in targeting and detecting prostate tumors. On this review, it is highlighted that the most promising positron emission tomography-tracers that will, in a near future, not only improve diagnostic abilities for prostate carcinoma but also open new possibilities for theranostic approaches to treat this malignancy at a world level. Keywords: Diagnosis, Imaging, Prostate cancer, Staging

Background The aim of this systematic review is to assess the role of 18-fluorodeoxyglucose positron emission tomography in the preoperative evaluation of intraductal papillary mucinous neoplasms and cystic lesions of the pancreas. Methods A computerized PubMed search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies evaluating positron emission tomography in the preoperative evaluation of pancreatic cystic lesions. Results A total of 14 studies evaluated the role of 18-fluorodeoxyglucose positron emission tomography/positron emission tomography-computed tomography, 9 of which evaluated only intraductal papillary mucinous neoplasms and 5 evaluated all pancreatic cystic lesions, including intraductal papillary mucinous neoplasms. Pooled analysis was carried out for studies evaluating intraductal papillary mucinous neoplasms only and studies evaluating all cystic lesions. Imaging with 18-fluorodeoxyblucose positron emission tomography had a positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of 90%, 91%, 85%, 95%, and 91% in identifying malignancy (defined as either invasive and/or high-grade dysplasia) in intraductal papillary mucinous neoplasms and a positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of 85%, 81%, 79%, 86%, and 88% in identifying malignancy in other cystic lesions. Pooled analysis reported the positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of Sendai consensus guidelines (SCG) criteria as 69%, 69%, 68%, 55%, and 58%. The Fukuoka consensus guidelines (FCG) only had sensitivity, specificity, and accuracy reported as 61%, 52%, and 52%, respectively. Conclusion The 18-fluorodeoxyblucose positron emission tomography had a high degree of accuracy of detecting malignancy in intraductal papillary mucinous neoplasm and cystic lesion of the pancreas. Comparison of the utility of positron emission tomography with the Fukuoka consensus guidelines and the Sendai consensus guidelines suggest that positron emission tomography is superior to present guidelines in detecting malignant intraductal papillary mucinous neoplasm and cystic lesion of the pancreas. Further studies in larger patient cohorts may be required to corroborate these findings and to determine the place of positron emission tomography in the management of intraductal papillary mucinous neoplasm and cystic lesions of the pancreas.

Aim There are few data to inform on the use of response assessment 2-[fluorine-18]-fluoro-2-deoxy- d -glucose (FDG) positron emission tomography-computed tomography (PET-CT) following radical radiotherapy without chemotherapy for head and neck squamous cell carcinoma (HNSCC). This retrospective study evaluated the accuracy of PET-CT in HNSCC following radical radiotherapy. Materials and methods In total, 138 patients with HNSCC treated with radical radiotherapy without chemotherapy who underwent a baseline and response assessment FDG PET-CT were identified. FDG PET-CT outcomes were analysed with reference to clinicopathological outcomes. Results The median follow-up was 26 months. FDG-avid disease at baseline was present for the primary site and lymph nodes in 118 and 86 patients, respectively. With regard to the primary tumour, the negative predictive value (NPV) of a complete metabolic response (CMR) was 95%; the positive predictive value (PPV) of equivocal uptake and a positive scan were 6% and 82%, respectively. The likelihood ratios for a CMR, equivocal and positive scans of the primary site were 0.19, 0.22, 14.8, respectively. With regard to lymph node disease, the NPV of a CMR was 91%, the PPV of equivocal uptake and a positive scan were 33% and 88%, respectively. Likelihood ratios for lymph node disease for CMR, equivocal and positive scans were 0.19, 0.97 and 15.1, respectively. Conclusion Compared with the accuracy reported in the literature following chemoradiotherapy, response assessment FDG PET-CT following radical radiotherapy without chemotherapy had a similarly high NPV, whereas the PPV following a positive scan was higher.

Background 68Gallium-DOTATATE positron emission tomography–computed tomography (PET CT) has shown superior accuracy in detecting grade 1 and 2 neuroendocrine tumors over previous imaging modalities and was recently included in National Comprehensive Cancer Network guidelines. It remains unclear which patients benefit most from this imaging modality. We therefore reviewed our initial experience with 68Gallium-DOTATATE PET CT to evaluate its usefulness in diagnosing, staging, and surveilling neuroendocrine tumors. Methods Records of patients who underwent 68Gallium-DOTATATE PET CT from March to December 2017 were prospectively evaluated. The primary endpoint was whether 68Gallium-DOTATATE PET CT changes treatment in patients with neuroendocrine tumors. Descriptive statistics, Fisher exact tests, and nested logistic regressions were conducted. Results A total of 50 consecutive patients were included. Of these, 41 patients (82%) had a biopsy-proven neuroendocrine tumor at the time of imaging. The remaining 9 patients (18%) had symptoms or biochemistry suggestive of a neuroendocrine tumor with negative cross-sectional imaging. 68Gallium-DOTATATE PET CT changed management in 33 patients (66%). There were 24 patients with intermodality changes in management and 9 patients with intramodality changes in management. Patients with scans performed for staging had a higher likelihood of a change in management (P = .006). Conclusion Performing 68Gallium-DOTATATE PET CT should be considered for staging and surveillance of neuroendocrine tumors because it is frequently associated with changes in management.

Introduction To evaluate the utility of positron emission tomography-computed tomography (PET/CT) as an imaging tool for the characterization of immune-mediated inner ear disease (IMIED), providing measurements of the inner ear region activity as well as detecting possible involvement of other organs. Material and methods The study included 28 patients with IMIED and 4 sex-matched and age-matched control subjects with no history of ear disease. Eighteen patients were considered to be suffering from primary IMIED and 10 patients from secondary. PET/CT scans with 18F-FDG were performed to assess systemic involvement as well as inner ear region activity. Interpretation of PET/CT scans was performed independently by two nuclear medicine physicians blinded to clinical history. In order to assess inter-rater agreement before performing the analysis of the inner ear, different Bland & Altman plots and the intraclass correlation coefficients were estimated. Results Different metabolically active foci findings were reported in 13 patients. Four patients diagnosed as primary IMIED showed thyroid and aorta activity. Regarding the inner-ear semiquantitative analysis, the inter-rater agreement was not sufficiently high. Comparisons between groups, performed using Mann–Whitney test or Kruskal–Wallis tests, showed no differences. Conclusions The study showed 18F-FDG PET/CT could be an important tool in the evaluation of IMIED as it can support the characterization of this entity providing the diagnosis of unknown or underestimated secondary IMIED. Nevertheless, we consider PET is not an adequate tool to approach the inner ear because of the small size and volume of the cochlea which makes the assessment very difficult.

Background Neoadjuvant chemotherapy (NAC) has become an essential treatment for breast cancer. However, there is still no consensus on the best tool to evaluate pathological response to NAC. Methods Two reviewers systematically searched Cochrane, PubMed, EMBASE, Web of Science, and CBM (last updated in February 2017) for eligible articles. We independently screened and selected studies that conformed to the inclusion criteria and extracted the requisite data. Pooled sensitivity, specificity, and the area under the SROC curve were calculated to estimate the diagnostic accuracy of magnetic resonance imaging (MRI) and positron emission computed tomography (PET/CT). And the relative DOR (RDOR) was used to compare accuracy for levels of the covariable. Results Thirteen studies involving 575 patients who underwent MRI and 618 who underwent PET/CT were included in our analysis. The pooled sensitivity and specificity of MRI were 0.88 (95% CI: 0.78–0.94) and 0.69 (95% CI: 0.51–0.83), respectively. The corresponding values for PET/CT were 0.77 (95% CI: 0.58–0.90) and 0.78 (95% CI: 0.63–0.88), respectively. The area under the SROC curve for MRI and PET/CT were 0.88 and 0.84, respectively. And the RDOR = 1.44 (95% CI, 0.46–4.47 P = 0.83). Conclusion MRI had a higher sensitivity and PET/CT had a higher specificity in predicting the pathologic response after NAC in patients with breast cancer. According to the area under the SROC curve and anatomic discriminative resolution, MRI is the more suitable recommendation for predicting the pathologic response after NAC.

Rationale and Objectives This study aimed to determine the diagnostic utility of standardized uptake values (SUV) and apparent diffusion coefficients (ADC) for assessment of focal and diffuse bone marrow involvement in patients with malignant lymphoma. Materials and Methods Sixty treatment-naive patients (28 males; mean age 51.2 ± 16.7 years) with histologically proven lymphoma, who underwent fludeoxyglucose (18F) positron emission tomography-computed tomography ([F18]-FDG-PET/CT) and whole-body diffusion-weighted imaging (WB-DWI) within 7 days, and also routine bone marrow biopsy, were included in this institutional review board-approved, retrospective study. The maximum SUV (SUVmax) on [F18]-FDG-PET/CT, and the mean ADC (ADCmean, ×10−3 mm2/s) on whole-body-DWI, were extracted from focal lesions, or, in their absence, from the thoracic (Th8) and lumbar vertebral bodies (L4), the sacral bone (S1), and the iliac crest. Lesion-to-liver-ratios (SUVmax-ratio) were calculated. Pearson correlation coefficients were used to assess the correlation between SUVmax-ratios and ADCmean values. Results Bone marrow involvement was observed in 16 of 60 patients (8 of 16 with diffuse infiltration). The SUVmax-ratio cutoff value was 95.25% for focal and 70.2% for diffuse bone marrow involvement (sensitivity/specificity of 87.5%/86.4% and 100%/43.2%, respectively). The ADCmean cutoff value was 0.498 for focal and 0.401 for diffuse bone marrow involvement (sensitivity/specificity of 100%/90.9% and 87.5%/56.8%, respectively). No significant correlations were found between SUVmax-ratios and ADCmean values in the different groups. Conclusion With the liver as reference tissue, quantitative [F18]-FDG-PET/CT may be useful to differentiate bone marrow involvement from normal bone marrow in patients with lymphoma, even though the specificity for diffuse marrow involvement is rather low. Quantitative DWI can be used only to distinguish focal bone marrow lesions from normal bone marrow.

In this paper, we investigate the sensitivities of positron decays on a one-zone model of type-I X-ray bursts. Most existing studies have multiplied or divided entire beta decay rates (electron captures and beta decay rates) by 10. Instead of using the standard Fuller & Fowler (FFNU) rates, we used the most recently developed weak library rates [1] , which include rates from Langanke et al.'s table (the LMP table) (2000) [2] , Langanke et al.'s table (the LMSH table) (2003) [3] , and Oda et al.'s table (1994) [4] (all shell model rates). We then compared these table rates with the old FFNU rates [5] to study differences within the final abundances. Both positron decays and electron capture rates were included in the tables. We also used pn -QRPA rates [6,7] to study the differences within the final abundances. Many of the positron rates from the nuclei's ground states and initial excited energy states along the rapid proton capture ( rp ) process have been measured in existing studies. However, because temperature affects the rates of excited states, these studies should have also acknowledged the half-lives of the nuclei's excited states. Thus, instead of multiplying or dividing entire rates by 10, we studied how the half-lives of sensitive nuclei in excited states affected the abundances by dividing the half-lives of the ground states by 10, which allowed us to set the half-lives of the excited states. Interestingly, we found that the peak of the final abundance shifted when we modified the rates from the excited states of the 105 Sn positron decay rates. Furthermore, the abundance of 80 Zr also changed due to usage of pn -QRPA rates instead of weak library rates (the shell model rates).

Background The cause of atrioventricular conduction block (AVB) remains unexplained in a significant number of patients. Granulomatous myocarditis is an uncommon but important cause of AVB. Fluorine-18 fluoro-2-deoxyglucose positron emission computed tomography (18-FDG PET) scan has emerged as a sensitive tool for diagnosing granulomatous myocarditis. Objective The purpose of this study was to evaluate the prognostic value of 18-FDG PET scan in patients with unexplained AVB. Methods Patients age 18–55 years presenting with unexplained AVB and requiring a permanent pacemaker were evaluated with a fasting 18-FDG PET scan. Transthoracic echocardiography was performed at baseline and at follow-up. Major adverse cardiac events (ventricular tachycardia, heart failure, cardiac death) were noted during follow-up. Results Over a period of 3 years, 35 patients (20 females, 15 males; mean age 43.67 ± 11.21 years) were included in the study. Abnormal myocardial FDG uptake was noted in 15 patients (42.8%). Four patients consented for biopsy of paracardiac FDG avid lymph nodes, which revealed granulomatous inflammation (one of which grew Mycobacterium tuberculosis in culture). Mean follow-up period was 24 months. Major adverse cardiac events were significantly higher in the patients with abnormal PET uptake ( P Conclusion Patients with high-degree AVB and abnormal myocardial 18-FDG PET uptake have more adverse cardiac events and worse outcomes. Early screening for myocardial inflammation and appropriate treatment may prevent these complications. Tuberculosis may be an important cause of unexplained AVB, apart from sarcoidosis, in developing countries such as India.

Antiangiogenic therapy is a universal approach to the treatment of malignant gliomas but fails to prolong the overall survival of newly diagnosed or recurrent glioblastoma patients. Imaging biomarkers are quantitative imaging parameters capable of objectively describing biological processes, pathological changes and treatment responses in some situations and have been utilized for outcome predictions of malignant gliomas in anti-angiogenic therapy. Advanced magnetic resonance imaging techniques (including perfusion-weighted imaging and diffusion-weighted imaging), positron emission computed tomography and magnetic resonance spectroscopy are imaging techniques that can be used to acquire imaging biomarkers, including the relative cerebral blood volume (rCBV), Ktrans, and the apparent diffusion coefficient (ADC). Imaging indicators for a better prognosis when treating malignant gliomas with antiangiogenic therapy include the following: a lower pre- or post-treatment rCBV, less change in rCBV during treatment, a lower pre-treatment Ktrans, a higher vascular normalization index during treatment, less change in arterio-venous overlap during treatment, lower pre-treatment ADC values for the lower peak, smaller ADC volume changes during treatment, and metabolic changes in glucose and phenylalanine. The investigation and utilization of these imaging markers may confront challenges, but may also promote further development of anti-angiogenic therapy. Despite considerable evidence, future prospective studies are critically needed to consolidate the current data and identify novel biomarkers., Highlights • Anti-angiogenic therapy only benefits specific populations of glioma patients. • Advanced imaging techniques can produce quantitative imaging biomarkers. • Physiological and metabolic parameter can predict outcome for anti-angiogenic therapy. • Larger prospective studies are needed to provide further evidence.

Positron emission tomography (PET) has revolutionized the diagnosis of cancer since its conception. When combined with computed tomography (CT), PET/CT performed in children produces highly accurate diagnoses from images of regions affected by malignant tumors. Considering the high risk to children when exposed to ionizing radiation, a dosimetric study for PET/CT procedures is necessary. Specific absorbed fractions (SAF) were determined for monoenergetic photons and positrons, as well as the S-values for six positron emitting radionuclides ( 11 C, 13 N, 18 F, 68 Ga, 82 Rb, 15 O), and 22 source organs. The study was performed for six pediatric anthropomorphic hybrid models, including the newborn and 1 year hermaphrodite, 5 and 10-year-old male and female, using the Monte Carlo N-Particle eXtended code (MCNPX, version 2.7.0). The results of the SAF in source organs and S-values for all organs showed to be inversely related to the age of the phantoms, which includes the variation of body weight. The results also showed that radionuclides with higher energy peak emission produces larger auto absorbed S-values due to local dose deposition by positron decay. The S-values for the source organs are considerably larger due to the interaction of tissue with non-penetrating particles (electrons and positrons) and present a linear relationship with the phantom body masses. The results of the S-values determined for positron-emitting radionuclides can be used to assess the radiation dose delivered to pediatric patients subjected to PET examination in clinical settings. The novelty of this work is associated with the determination of auto absorbed S-values, in six new pediatric virtual anthropomorphic phantoms, for six emitting positrons, commonly employed in PET exams.

Purpose Adjuvant internal mammary lymph node (IMN) radiation is often delivered with 2-dimensional techniques that use anatomic landmarks and predetermined depths for field placement and dose specification. In contrast, 3-dimensional planning uses the internal mammary vessels (IMVs) to localize the IMNs for planning. Our purpose was to determine if localization of the involved IMN (i-IMN) by 18 F-labeled fluorodeoxyglucose positron emission tomography-computed tomography ( 18 F-FDG PET-CT) offers opportunities to improve treatment. Methods and materials Breast cancer patients (n = 80) who had i-IMNs (n = 112) on PET-CT for initial staging (n = 40) or recurrence (n = 40) were studied. Size, intercostal space (IC), and distance from skin, sternum, and IMVs were recorded. Effects on 2- and 3-dimensional planning were evaluated. Results Most i-IMNs (94.6%) were in the first to third ICs. Few were in the fourth (4.5%) or fifth (0.9%) IC. Mean i-IMN depth was 3.4 cm (range, 1.1-7.3 cm). Prescriptive depths of 4, 5, and 6 cm would result in undertreatment of 25%, 10.7%, and 5.3% of IMNs, respectively. Most IMNs (86.6%) were lateral or adjacent to the sternal edge. Only 13.4% of IMNs were posterior to the sternum. Use of the ipsilateral or contralateral sternal edge for field placement increases the risk of geographic miss or excess normal tissue exposure. Most i-IMNs were adjacent to (83%) or ≤0.5 cm (14%) from the IMV edge. Three (3%) were >0.5 cm beyond the IMV edge. The clinical target volume (CTV) defined by the first to third ICs encompassed 78% of i-IMNs. IMN-CTV coverage of i-IMNs increased with inclusion of the fourth IC (82%), 0.5 cm medial and lateral margin expansion (93%), or both (96.5%). Conclusion Two-dimensional treatment techniques risk geographic miss of IMNs and exposure of excess normal tissue to radiation. An IMN-CTV defined by the IMVs from the first to third ICs with 0.5-cm medial and lateral margin expansion encompasses almost all i-IMNs identified on PET-CT imaging. Inclusion of the fourth IC offers modest coverage improvement, and its inclusion should be weighed against potential increase in cardiac exposure. Summary The use of 2-dimensional treatment techniques for adjuvant internal mammary lymph node (IMN) radiation may cause geographic miss of tumor and expose normal tissue to radiation injury. Conformal 3-dimensional planning improves coverage and reduces risk of normal tissue damage by using the internal mammary vessel to define an IMN clinical target volume (CTV). Contouring the IMN-CTV from the first to third intercostal spaces with a 0.5-cm expansion medially and laterally encompasses most IMN. Positron emission tomography-computed tomography may have a role in radiation planning by identifying involved-IMN for dose escalation.

According to World Health Organization (WHO) cancer is the second most important cause of death globally. Because angiogenesis is considered as an essential process of growth, proliferation and tumor progression, within this review we decided to shade light on recent development of chemical compounds which play a significant role in its imaging and monitoring. Indeed, the review gives insight about the current achievements of active agents structures involved in imaging techniques such as: positron emission computed tomography (PET), magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT), as well as combination PET/MRI and PET/CT. The review aims to provide the journal audience with a comprehensive and in-deep understanding of chemistry policy in tumor angiogenesis imaging.

Recent results on e + e − annihilation to hadrons from SND experiment at VEPP-2000 and VEPP-2M colliders are presented. Corresponding data set is about 100 pb−1 of integrated luminosity collected at the energy region s below 2 GeV. The processes e + e − → K + K − , π 0 γ , η π + π − π 0 and ω π 0 η have been studied.

Positron emission tomography–computed tomography (PET/CT) combines both functional and anatomic information and provides in vivo molecular information on biological processes that can be useful at different steps of evolution of thyroid cancers. 18Fluorodeoxyglucose being highly trapped in rapidly dividing cells makes 18F-FDG-PET recommended in the staging, prognostic evaluation and follow-up of metastatic and/or of poorly differentiated thyroid carcinomas. 18F-FDG PET/CT can help in the localization of persistent/recurrent disease. However, its sensitivity depends widely on tumor burden and histology. Iodine 124 (124I) is currently under evaluation for diagnosis and pretherapeutic dosimetry planning. PET/CT using 18F-FDOPA is the most sensitive radiopharmaceutical for localizing persistent/recurrent medullary thyroid carcinoma (MTC). However, its sensitivity depends on calcitonin levels, with a threshold value of around 150 pg/mL. 18F-FDG PET/CT can also be used in MTC with short calcitonin or CEA doubling time.

A 67-year-old male presented with papilledema and back pain localized to the T10 level. Initial workup revealed multifocal spinal ependymoma which was resected and treated with external beam radiotherapy. Nine years after treatment, the patient had a relapse of back pain, and MRI was inconclusive in distinguishing posttreatment radiation necrosis from recurrent tumor. We present the first described report with the utilization of multiparametric positron emission tomography-magnetic resonance imaging and perfusion MRI to distinguish recurrent spinal ependymoma from radiation necrosis.

A novel detection algorithm for Positron Emission Particle Tracking (PEPT) with multiple tracers based on optical feature point identification (FPI) methods is presented. This new method, the FPI method, is compared to a previous multiple PEPT method via analyses of experimental and simulated data. The FPI method outperforms the older method in cases of large particle numbers and fine time resolution. Simulated data show the FPI method to be capable of identifying 100 particles at 0.5 mm average spatial error. Detection error is seen to vary with the inverse square root of the number of lines of response (LORs) used for detection and increases as particle separation decreases.

Aims\ud To investigate the use of image co-registration in incorporating diagnostic positron emission tomography-computed tomography (PET-CT) directly into the radiotherapy treatment planning pathway, and to describe the pattern of local recurrence relative to the PET-avid volume.\ud \ud Materials and methods\ud Fourteen patients were retrospectively identified, six of whom had local recurrence. The accuracy of deformable image registration (DIR) and rigid registration of the diagnostic PET-CT and recurrence CT, to the planning CT, were quantitatively assessed by comparing co-registration of oesophagus, trachea and aorta contours. DIR was used to examine the correlation between PET-avid volumes, dosimetry and site of recurrence.\ud \ud Results\ud Positional metrics including the dice similarity coefficient (DSC) and conformity index (CI), showed DIR to be superior to rigid registration in the co-registration of diagnostic and recurrence imaging to the planning CT. For diagnostic PET-CT, DIR was superior to rigid registration in the transfer of oesophagus (DSC = 0.75 versus 0.65, P < 0.009 and CI = 0.59 versus 0.48, P < 0.003), trachea (DSC = 0.88 versus 0.65, P < 0.004 and CI = 0.78 versus 0.51, P < 0.0001) and aorta structures (DSC = 0.93 versus 0.86, P < 0.006 and CI = 0.86 versus 0.76, P < 0.006). For recurrence imaging, DIR was superior to rigid registration in the transfer of trachea (DSC = 0.91 versus 0.66, P < 0.03 and CI = 0.83 versus 0.51, P < 0.02) and oesophagus structures (DSC = 0.74 versus 0.51, P < 0.004 and CI = 0.61 versus 0.37, P < 0.006) with a non-significant trend for the aorta (DSC = 0.91 versus 0.75, P < 0.08 and CI = 0.83 versus 0.63, P < 0.06) structure. A mean inclusivity index of 0.93 (range 0.79–1) showed that the relapse volume was within the planning target volume (PTVPET-CT); all relapses occurred within the high dose region.\ud \ud Conclusion\ud DIR is superior to rigid registration in the co-registration of PET-CT and recurrence CT to the planning CT, and can be considered in the direct integration of PET-CT to the treatment planning process. Local recurrences occur within the PTVPET-CT, suggesting that this is a suitable target for dose-escalation strategies.

We have recently reported that administration of thin graphene oxide (GO) sheets in the systemic circulation of rodents leads to rapid urinary excretion for the majority of injected dose and accumulation by the reticuloendothelial system organs for the remaining dose. In this study, graphene oxide was functionalized with a chelating moiety (DOTA, (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)) and labeled with [ 64 Cu] for positron emission computed tomography (PET/CT) imaging. The thin functionalized graphene oxide material ( f- GO-thin) consisted of a few layers (∼5 nm) in thickness. Aging of the f- GO-thin material led to re-stacking of the flakes that resulted in materials of increased thickness ( f -GO-thick) without altering their lateral dimension. These two types of f- GOs were comparatively studied pharmacologically to reveal the previously unexplored in vivo role of graphene oxide sheet thickness. Our results showed that a significantly larger fraction of the thicker GO sheets (47.5% of injected dose) remained within the body of living animals 24 h after intravenous administration, residing mainly in the spleen and liver. The thinner GO sheets were predominantly (76.9% of injected dose) excreted through the glomerular filter into the urine. This pilot study provides an initial correlation between graphene-based material structure and pharmacological profile that is imperative towards understanding of how 2D structures behave in vivo to give information on potential biomedical applications.

Since the introduction of anatomical and functional imaging with multiparametric magnetic resonance imaging and choline or prostate-specific membrane antigen positron emission tomography–computed tomography, we are able to diagnose a previously unknown disease, the oligometastatic prostate cancer after local therapy. Reports on surgical and radiation treatment for low-volume metastatic recurrence have shown promising results, with definitive cure in few but a relevant delay of androgen-deprivation therapy with both treatment methods. Obviously, these results need to be validated with prospective randomised data.

To evaluate the prognostic utility of 2-[(18)F] fluoro-2-deoxy-d-glucose positron emission tomography-computed tomography (FDG PET-CT) carried out in the third week (iPET) and after completion (pPET) of definitive radiation therapy in patients with mucosal primary head and neck squamous cell carcinoma (MPHNSCC) and to investigate the optimal visual grading criteria for therapy response assessment.Sixty-nine consecutive patients with newly diagnosed MPHNSCC treated with radical radiation therapy with or without systemic therapy underwent staging. PET-CT, iPET and pPET were included. All PET-CT images were reviewed by using a visual grading system to assess metabolic response for primary tumour: 0 = similar to adjacent background blood pool activity; 1 = more than background but mediastinal blood pool; 2 ≥ mediastinal blood pool andliver; 3 ≥ liver; and 4 ≥ brain. The results were correlated with locoregional recurrence-free survival (LRFS), disease-free survival (DFS) and overall survival, using Kaplan-Meier analysis.The median follow-up was 28 months (range 6-62), the median age was 61 years (range 39-81) and AJCC 7th edition clinical stage II, III and IV were six, 18 and 45 patients, respectively. The optimal threshold for non-complete metabolic response (non-CMR) was defined as focal uptake ≥ liver (grade 3) for iPET and focal uptake ≥ mediastinum (grade 2) for pPET. The 2 year Kaplan-Meier LRFS, DFS and overall survival estimates for primary CMR and non-CMR in iPET were 89.8% versus 71.5% (P = 0.062), 80.1% versus 65.3% (P = 0.132), 79.1% versus 72.1% (P = 0.328) and in pPET 86.2% versus 44.6% (P = 0.0005), 77.6% versus 41.2% (P = 0.006), 81.2% versus 40.6% (P = 0.01), respectively. The negative predictive value (NPV) for LRFS for patients achieving both primary and nodal CMR in iPET was 100%. No locoregional failure was observed in patients with both primary and nodal iPET CMR (P = 0.038), whereas those with nodal iPET CMR had no regional failure (P = 0.033). However, the positive predictive values (PPV) for LRFS and DFS for iPET and pPET were found to be poor: 30% and 36% for iPET and 35% and 39% for pPET, respectively.Standardised criteria using visual assessment are feasible. The metabolic response using visual assessment with standardised interpretation criteria of iPET and pPET can be useful predictors of tumour control. Dose de-escalation can be considered on the basis of a high NPV for iPET. However, the PPV of iPET is poor, indicating that additional discriminative tools are needed.

Positron emission particle tracking (PEPT) is used to study the behavior of flow in a rectangular test section. A multiple-particle tracking technique (multi-PEPT) is proposed and tested using a once-through flow system and a preclinical positron emission tomography (PET) scanner. This measurement is then compared to particle image velocimetry (PIV) and high-speed particle tracking velocimetry (PTV) studies of the same test section. Uncertainties in the established flow measurement methods used to validate the PEPT performance are quantified. Mean flow velocity are compared as measured by the three methods. Minor variations are exposed in the data comparisons, and uncertainty exists due to the statistical nature of our PEPT method. Nonetheless, multi-PEPT is shown to be capable as a means of examining characteristics of a complex flow regime.

We describe a new positron emission time-of-flight apparatus using liquid xenon. The detector is based in a liquid xenon scintillating cell. The cell shape and dimensions can be optimized depending on the intended application. In its simplest form, the liquid xenon scintillating cell is a box in which two faces are covered by silicon photomultipliers and the others by a reflecting material such as Teflon. It is a compact, homogenous and highly efficient detector which shares many of the desirable properties of monolithic crystals, with the added advantage of high yield and fast scintillation offered by liquid xenon. Our initial studies suggest that good energy and spatial resolution comparable with that achieved by lutetium oxyorthosilicate crystals can be obtained with a detector based in liquid xenon scintillating cells. In addition, the system can potentially achieve an excellent coincidence resolving time of better than 100 ps.

We investigate even-even nuclei in the $A\sim70$ mass region within the framework of the proton-neutron quasi-particle random phase approximation (\mbox{pn-QRPA}) and the interacting boson model-1 (\mbox{IBM-1}). Our work includes calculation of the energy spectra and the potential energy surfaces $V(\beta,\gamma)$ of Zn, Ge, Se, Kr and Sr nuclei with the same proton and neutron number, $N = Z$. The parametrization of the \mbox{IBM-1} Hamiltonian was performed for the calculation of the energy levels in the ground state bands. Geometric shape of the nuclei was predicted by plotting the potential energy surfaces $V(\beta,\gamma)$ obtained from the \mbox{IBM-1} Hamiltonian in the classical limit. The \mbox{pn-QRPA} model was later used to compute half-lives of the neutron-deficient nuclei which were found to be in very good agreement with the measured ones. The \mbox{pn-QRPA} model was also used to calculate the Gamow-Teller strength distributions and was found to be in decent agreement with the measured data. We further calculate the electron capture and positron decay rates for these $N$ = $Z$ waiting point (WP) nuclei in the stellar environment employing the \mbox{pn-QRPA} model. For the $rp$-process conditions, our total weak rates are within a factor two compared with the Skyrme HF+BCS+QRPA calculation. All calculated electron capture rates are comparable to the competing positron decay rates under $rp$-process conditions. Our study confirms the finding that electron capture rates form an integral part of the weak rates under $rp$-process conditions and should not be neglected in the nuclear network calculations., Comment: 25 pages, 13 figures, 5 tables

Purpose To evaluate the feasibility of adaptive planning using positron emission tomography–computed tomography (PET-CT) in locally advanced non-small cell lung cancer. Methods and materials Patients with locally advanced non-small cell lung cancer receiving definitive radiation therapy (RT) were eligible. Initial planning PET-CT was performed and a conventional RT plan (2 Gy/fraction to 60 Gy) was designed. A second planning PET-CT was obtained at ~50 Gy. Dose escalation to ~70 Gy for residual fludeoxyglucose-avid disease was pursued at the discretion of the treating oncologists. The primary endpoint was feasibility of adaptive planning using interim PET-CT. Normal tissue dose-volume parameters were calculated for both adaptive and simulated nonadaptive plans. Results From 2012 to 2014, 33 eligible patients were enrolled and underwent planning PET-CT, 3 of which were found to have new distant metastases. Of 30 patients who initiated RT, interim PET-CT was obtained in 29. This showed complete response in 2 patients, partial response/stable disease in 24, and new distant metastases in 3. Selective dose escalation was performed in 17 patients. For those receiving a boost, the median gross tumor volumes pre-RT and at ~50 Gy were 78 mL and 29 mL, respectively ( P = .01). Reasons for no dose escalation were normal tissue constraints (n = 3), poorly defined residual disease (n = 2), acute toxicity (n = 1), and refusal of further therapy (n = 1). Adaptive planning compared with a simulated nonadaptive approach allowed for significant dose reductions to the lungs, heart, and esophagus (all P Conclusions Adaptive planning using PET-CT was feasible and allows for significant dose reductions to normal tissues compared with traditional planning techniques.

A novel approach to positron emission particle tracking is presented based on determining regions of space with high density of line of response crossing via clustering. The method is shown to be able to accurately track multiple particles in systems where the number of particles is unknown and in which particles can enter and leave the field of view of the scanning system. This method is explored in various environments and its parametric dependence is studied.

This paper presents the results of using positron emission particle tracking to record the trajectories of large ( O≈ 1440 μm) and small ( O≈ 58 μm) particles of hematite (S.G.=5.3) and quartz (S.G.=2.7) in a slurry of iron ore (20% solids w/w) flowing in a gravity spiral concentrator. The tracking was undertaken using modular positron emission particle tracking detectors (ECAT 951) assembled and calibrated for this purpose. The tracer particles used were generated by the direct activation of large particles in a cyclotron beam ( 3 He, 35 MeV), in the Positron Imaging Centre at the University of Birmingham. These larger particles were then broken and sized to isolate small active particles when required. The behaviour of the valuable and gangue particles in the first two turns of the spiral is presented. The formation and interaction of different bands of similar size/density particles is shown. For small particles, these bands are less defined and can be present at different radial positions on the trough for the same size and density material. Their formation and dispersion is influenced by the flow of the slurry. Part of the large dense hematite particles are shown concentrating toward the inside of the spiral trough while some others are shown remaining in the high flow-speed outer zone outside of a band of large quartz particles. The behaviour in the feed device and first 0.3 turn of the spiral is related to the later separation of some of the large particles and this highlights the effect of the feed radial distribution of the particles on the trough.

This review discusses the clinical value of 18F-dihydroxyphenylalanine positron emission tomography-computed tomography (18F-FDOPA PET/CT) across the spectrum of neuroendocrine tumors (NETs). The rationale for 18F-FDOPA imaging is generally based on the ability of NETs to take up and decarboxylate amine precursors. The kinetics of tumor uptake and retention varies according to tumor type. For some tumor types, the imaging protocol might include early-time acquisitions in order not to miss cases with rapid washout, or carbidopa premedication to overcome physiological pancreatic uptake. The roles of 18F-FDOPA PET/CT imaging will be examined in diverse settings of patients with MTC, digestive NET, congenital hyperinsulinism and pheochromocytomas/paragangliomas. In each clinical setting, the diagnostic accuracy of 18F-FDOPA PET/CT is compared to that offered by conventional imaging methods or other PET tracers, such as 68Ga-labeled somatostatin analogs or 18F-FDG.

Objective: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by small endocrine tumors that secrete fibroblast growth factor 23 (FGF23), a phosphaturic hormone.Abbreviations: CT = computed tomography; FGF23 = fibroblast growth factor 23; Ga68-DOTANOC = (68)Galliumlabeled (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-1-NaI(3)-octreotide; MRI = magnetic resonance imaging; PET = positron emission tomography; PMTMCT = primitive appearing mixed connective tissue tumors; SSR = somatostatin receptor; TIO = tumor-induced osteomalaciaMethods: A 44-year-old male was evaluated following complaints of progressive leg pain, difficulty walking, and muscle pain over the previous 9 years. Biochemical evaluation showed low serum phosphorus, high urine phosphorus, and elevated FGF23 levels. These findings were suggestive of TIO. A whole-body (68)Gallium-labeled (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-1-NaI(3)-octreotide positron emission tomography–computed tomography scan revealed a large vascular lesion in the anterior squamous portion of the right temporal lobe and right greater wing of the sphenoid bone, involving the posterolateral wall of the right orbit. Axial T1-weighted magnetic resonance imaging revealed isointense lesions containing multiple vascular channels. The histomorphologic feature of the excised tumor was compatible with a phosphaturic mesenchymal tumor, mixed cell type. Serum phosphorus and FGF23 levels normalized after excision of the tumor and resulted in healing of the fractured femur.Results: We report a large vascular lesion in the anterior squamous portion of the right temporal lobe and right greater wing of the sphenoid bone, involving the posterolateral wall of the right orbit as a cause of TIO.Conclusion: TIO is a fascinating paraneoplastic syndrome and is an important cause of adult-onset hypophosphatemia. Localization of tumors in cases of TIO is difficult and a stepwise approach with functional and anatomic imaging is usually successful in 90% of the cases. Excision of the tumor cures this debilitating disease, although recurrence is possible.

ObjectivesAn assay for molecular imaging of myocardial CXCR4 expression was evaluated, in order to obtain mechanistic insights noninvasively based on quantitative positron emission tomography (PET).BackgroundThe chemokine receptor CXCR4 has emerged as a therapeutic target after acute myocardial infarction (AMI), because of its role in inflammatory and progenitor cell recruitment.MethodsPET with the specific CXCR4 ligand, gallium-68 (68Ga)-pentixafor, was performed in mice (n = 53) and compared with ex vivo autoradiography, immunohistochemistry, and left ventricular flow cytometry. In addition, 12 patients were imaged at 2 to 8 days after AMI.ResultsIn mice, 68Ga-pentixafor identified regional CXCR4 upregulation in the infarct region, peaking at 3 days (infarct/remote [I/R] ratio 1.5 ± 0.2 at 3 days vs. 1.2 ± 0.3 at 7 days; p = 0.03), corresponding to a flow cytometry-based peak of CD45+ leukocytes and immunohistochemical detection of CD68+ macrophages and Ly6G+ granulocytes. Blockade with the CXCR4 antagonist AMD3100 abolished the signal. No specific uptake was found in sham-operated or control animals. Long-term treatment with oral enalapril attenuated the CXCR4 signal (I/R 1.2 ± 0.2 at 3 days and 1.0 ± 0.0.1 at 7 days; p = 0.01 vs. untreated). Patients showed variable degrees of CXCR4 upregulation in the infarct region. No single clinical parameter allowed for prediction of CXCR4 signal strength. At multivariate analysis, a combination of infarct size and time after reperfusion predicted the CXCR4 infarct signal (rmultiple = 0.73; p = 0.03). Infarct signal in the myocardium was paralleled by elevated pentixafor uptake in bone marrow (r = 0.61; p = 0.04), which highlighted systemic interactions.ConclusionsTargeted PET imaging with 68Ga-pentixafor identifies the global and regional CXCR4 expression pattern in myocardium and systemic organs. CXCR4 upregulation after AMI coincides with inflammatory cell infiltration, but shows interindividual variability in patients. This may have implications for the response to CXCR4- or other inflammation-targeted therapy, and for subsequent ventricular remodeling.

We have observed β+-delayed α and pα emission from the proton-rich nucleus 21Mg produced at the ISOLDE facility at CERN. The assignments were cross-checked with a time distribution analysis. This is the third identified case of βpα emission. We discuss the systematic of beta-delayed particle emission decays, show that our observed decays fit naturally into the existing pattern, and argue that the patterns are to a large extent caused by odd-even effects.

This research aimed to analyze the dynamic changes of postoperative infection and neuron-specific enolase (NSE) levels in serum in non-small cell lung cancer (NSCLC) patients, and to provide assistance for the monitoring and diagnosis of NSCLC patients. 110 NSCLC patients from January 2017 to January 2019 were selected as the research objects. Preoperative Tumor node (TNM) staging was first recorded. Patients were examined by Positron Emission /Computed Tomography (PET/CT) and their Metabolic tumor volume (MTV) was recorded. Then, pulmonary infection was recorded every 12 hours on first three days after surgery. Finally, patients were followed up for 4 years to record their total survival time and 1-4 year survival rate. SPSS software was used to draw the Kaplan-Meier survival curve of patients, and Cox proportional hazard model was used to analyze the risk factors related to the prognosis of patients. The results showed that the higher the TNM stage, the shorter the patient's survival time; the infection rate decreased with the passage of time; the survival rate of patients with MTV less than 5.379 was significantly higher than that of patients with MTV greater than 5.379 (P

The SnO2 68Ge/68Ga generator system is widely used in medical imaging to provide a regular supply of the radionuclide 68Ga (T½ = 68.3 min) for positron emission tomography (PET). These generators are also used to supply 68Ga for the fabrication of tracer particles for application in positron emission particle tracking (PEPT). The tracer particles are fabricated by radiolabelling ion exchange resins such as Purolite NRW100 with 68Ga; however, contaminants from the degradation of the SnO2 column over time interfere with the uptake of 68Ga. The major contaminants are Zn(II), Fe(III) and Sn(IV) with 68Ge (IV) being eluted from the column as it degrades. This paper describes an improved method to purify the 68Ga supply using an Amberchrom CG-71m absorption resin column integrated into a newly designed separation panel. This method reduces the amount of Zn(II) and Fe(III) in the 68Ga eluate and improves the radiolabelling performance by more than 10% when compared to the un-purified product. The method can extend the life-span of the generator by several months.

We found the work of Byrne et al. [(1)][1] interesting. The results left little doubt that myocardial blood flow (MBF) reserve decreased linearly with increasing caffeine ingestion. These findings have many significant clinical implications, including the use of adenosine stress positron emission

We apply positron emission particle tracking (PEPT) to a gas–solid fluidized bed with injection of a secondary gas through a centrally arranged nozzle and present a method to compute stationary fluid-dynamic characteristics of the system from the trajectories of a test particle. In order to evaluate this non-invasive method we compare the field of density obtained by PEPT with the density obtained by a traditional, well-established and approved, yet invasive, measurement technique to find good agreement. Besides the penetration depth of the jet region and the opening angle of the jet which are inferred from the density field, we use PEPT to measure quantities whose measurement using traditional methods is rather sophisticated, including the residence time of particles in the jet region and the suspended phase, the coefficients of axial and radial dispersion and the material flux across the jet boundaries. We conclude that PEPT is a reliable and at the same time versatile technique to measure stationary fluid-dynamic properties of dynamical particle systems at spatial resolution only limited by the duration of the measurement.

We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.