On Imprimitive Representations of Finite Reductive Groups in Non-defining Characteristic

In this paper, we begin with the classification of Harish-Chandra imprimitive representations in non-defining characteristic. We recall the connection of this problem to certain generalizations of Iwahori-Hecke algebras and show that Harish-Chandra induction is compatible with the Morita equivalence by Bonnaf\'{e} and Rouquier, thus reducing the classification problem to quasi-isolated blocks. Afterwards, we consider imprimitivity of unipotent representations of certain classical groups. In the case of general linear and unitary groups, our reduction methods then lead to results for arbitrary Lusztig series

The role of the urban landscape on species with contrasting dispersal ability: insights from greening plans for Barcelona

With the expansion of urban areas, promoting urban biodiversity is now a priority. Many municipalities are implementing greening strategies to improve and increase green space within city boundaries. The effectiveness of these strategies, while rarely assessed, likely depends on the landscape and on relevant species intrinsic traits such as dispersal ability. Using a spatially explicit individual-based model, we evaluated the effect of the urban landscape on the projected distribution of three butterfly species with contrasting dispersal abilities, and assessed the effectiveness of the Barcelona greening strategy as a case study. Species distribution (in terms of patch occupancy) and effectiveness (in terms of population size and number of occupied gardens) were analysed using generalised linear models. The percentage of (semi) natural source area around each urban green space (garden hereafter) was the most important variable for the distribution of all three types of species, followed by the percentage of neighbouring gardens and by the garden carrying capacity, although the effect of neighbouring gardens was negative in the early phase of colonisation. The planned Barcelona greening strategy increased the number of gardens occupied by high and medium, but not by low dispersive species. Increasing the carrying capacity of the gardens improved colonisation for all three species types. While the best strategies can be context dependent, our results indicated that increasing garden area might be more effective in the long term but it can be overridden by garden capacity in the short term, especially if there are constraints to increasing garden area

Prostate Cancer: Value of Multiparametric MR Imaging at 3 T for Detection—Histopathologic Correlation1

Combined use of anatomic (T2-weighted MR imaging) and functional (MR spectroscopy and dynamic contrast material–enhanced MR imaging) modalities improves the performance of MR imaging for prostate tumor detection

The Kinetics and Reproducibility of 18

We evaluated the kinetics of (18)F-sodium fluoride (NaF) and reassessed the recommended dose, optimal uptake period, and reproducibility using a current-generation PET/CT scanner. METHODS: In this prospective study, 73 patients (31 patients with multiple myeloma or myeloma precursor disease and 42 with prostate cancer) were injected with a mean administered dose of 141 MBq of (18)F-NaF. Sixty patients underwent 3 sequential sessions of 3-dimensional PET/CT of the torso beginning ~15 min after (18)F-NaF injection, followed by a whole-body 3-dimensional PET/CT at 2 h. The remaining 13 prostate cancer patients were imaged only at 2 and 3 h after injection. Twenty-one prostate cancer patients underwent repeat baseline studies (mean interval, 5.9 d) to evaluate reproducibility. RESULTS: The measured effective dose was 0.017 mSv/MBq, with the urinary bladder, osteogenic cells, and red marrow receiving the highest doses at 0.080, 0.077, and 0.028 mGy/MBq, respectively. Visual analysis showed that uptake in both normal and abnormal bone increased with time; however, the rate of increase decreased with time. A semiautomated workflow provided objective uptake parameters, including the mean standardized uptake value of all pixels within bone with SUVs greater than 10 and the average of the mean SUV of all malignant lesions identified by the algorithm. The values of these parameters for the images beginning at ~15 min and ~35 min were significantly different (0.3% change/minute). Differences between the later imaging time points were not significant (P < 0.01). Repeat baseline studies showed high intraclass correlations (>0.9) and relatively low critical percent change (the value above which a change can be considered real) for these parameters. The tumor-to-normal bone ratio, based on the SUV(max) of identified malignant lesions, decreased with time; however, this difference was small, estimated at ~0.16%/min in the first hour. CONCLUSION: (18)F-NaF PET/CT images obtained with modest radiation exposures can result in highly reproducible imaging parameters. Although the tumor-to-normal bone ratio decreases slightly with time, the high temporal dependence during uptake periods < 30 min may limit accurate quantitation. An uptake period of 60 ± 30 min has limited temporal dependence while maintaining high tumor-to-normal bone ratio

\u3csup\u3e18\u3c/sup\u3eF-DCFBC Prostate-Specific Membrane Antigen-Targeted PET/CT Imaging in Localized Prostate Cancer: Correlation with Multiparametric MRI and Histopathology

© Wolters Kluwer Health, Inc. All rights reserved. Purpose To assess the ability of (N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-18F-fluorobenzyl-l-cysteine) (18F-DCFBC), a prostate-specific membrane antigen-Targeted PET agent, to detect localized prostate cancer lesions in correlation with multiparametric MRI (mpMRI) and histopathology. Methods This Health Insurance Portability and Accountability Act of 1996-compliant, prospective, institutional review board-Approved study included 13 evaluable patients with localized prostate cancer (median age, 62.8 years [range, 51-74 years]; median prostate-specific antigen, 37.5 ng/dL [range, 3.26-216 ng/dL]). Patients underwent mpMRI and 18F-DCFBC PET/CT within a 3 months\u27 window. Lesions seen on mpMRI were biopsied under transrectal ultrasound/MRI fusion-guided biopsy, or a radical prostatectomy was performed. 18F-DCFBC PET/CT and mpMRI were evaluated blinded and separately for tumor detection on a lesion basis. For PET image analysis, MRI and 18F-DCFBC PET images were fused by using software registration; imaging findings were correlated with histology, and uptake of 18F-DCFBC in tumors was compared with uptake in benign prostatic hyperplasia nodules and normal peripheral zone tissue using the 80% threshold SUVmax. Results A total of 25 tumor foci (mean size, 1.8 cm; median size, 1.5 cm; range, 0.6-4.7 cm) were histopathologically identified in 13 patients. Sensitivity rates of 18F-DCFBC PET/CT and mpMRI were 36% and 96%, respectively, for all tumors. For index lesions, the largest tumor with highest Gleason score, sensitivity rates of 18F-DCFBC PET/CT and mpMRI were 61.5% and 92%, respectively. The average SUVmax for primary prostate cancer was higher (5.8 ± 4.4) than that of benign prostatic hyperplasia nodules (2.1 ± 0.3) or that of normal prostate tissue (2.1 ± 0.4) at 1 hour postinjection (P = 0.0033). Conclusions The majority of index prostate cancers are detected with 18F-DCFBC PET/CT, and this may be a prognostic indicator based on uptake and staging. However, for detecting prostate cancer with high sensitivity, it is important to combine prostate-specific membrane antigen PET/CT with mpMRI

18F-DCFPyL PET/CT Imaging in Patients with Biochemically Recurrent Prostate Cancer After Primary Local Therapy

© 2020 by the Society of Nuclear Medicine and Molecular Imaging. Our objective was to investigate the lesion detection rate of 18F-DCFPyL PET/CT, a prostate-specific membrane antigen (PSMA)-targeted PET agent, in patients with biochemically relapsed prostate cancer after primary local therapy. Methods: This was a prospective institutional review board-approved study of 90 patients with documented biochemical recurrence (median prostate-specific antigen [PSA], 2.5 ng/mL; range, 0.21-35.5 ng/mL) and negative results on conventional imaging after primary local therapies, including radical prostatectomy (n = 38), radiation (n = 27), or a combination of the two (n = 25). Patients on androgen deprivation therapy were excluded. Patients underwent whole-body 18F-DCFPyL PET/CT (299.9 ± 15.5 MBq) at 2 h after injection. The PSMA PET lesion detection rate was correlated with PSA, PSA kinetics, and original primary tumor grade. Results: Seventy patients (77.8%) showed positive PSMA PET results, with a total of 287 lesions identified: 37 prostate bed foci, 208 lesions in lymph nodes, and 42 in distant sites in bones or organs, Eleven patients had negative results, and 9 patients showed indeterminate lesions, which were considered negative in this study. The detection rates were 47.6% (n = 10/21), 50% (n = 5/10), 88.9% (n = 8/9), and 94% (n = 47/50) for PSA levels of \u3e0.2 to \u3c0.5, 0.5 to \u3c1.0, 1 to \u3c2.0, and ≥2.0 ng/mL, respectively. In postsurgical patients, PSA, PSA doubling time, and PSA velocity correlated with PET results, but the same was not true for postradiation patients. These parameters also correlated with the extent of disease on PET (intrapelvic vs. extrapelvic). There was no significant difference in the rate of positive scans between patients with higher-grade and lower-grade primary tumors (Gleason score of ≥4 + 3 vs. \u3c3 + 4). Tumor recurrence was histology-confirmed in 40% (28/70) of patients. On a per-patient basis, positive predictive value was 93.3% (95% confidence interval, 77.6%-99.2%) by histopathologic validation and 96.2% (95% confidence interval, 86.3%-99.7%) by the combination of histology and imaging/clinical follow-up. Conclusion:18F-DCFPyL PET/CT imaging offers high detection rates in biochemically recurrent prostate cancer patients and is positive in about 50% of patients with a PSA level of less than 0.5 ng/mL, which could substantially impact clinical management. In postsurgical patients, 18F-DCFPyL PET/CT correlates with PSA, PSA doubling time, and PSA velocity, suggesting it may have prognostic value. 18F-DCFPyL PET/CT is highly promising for localizing sites of recurrent prostate cancer