35 research outputs found
Whatâs next? Preparing for the Next Leadership Position
Many department chairs eventually return to their faculty positions. However, for some of us the department chair position is a stepping stone for advancing to higher administrative ranks. This interactive session will provide suggestions on how to prepare for applying for leadership positions above the department chair
Upstairs/Downstairs: Moving up and down through leadership roles
The presenters will discuss the challenges they encountered moving up from department chair into the role of dean and associate dean, and the back down into the role of a chair. We will engage participants through interactive discussion in several case studies
Case Studies in Mentoring Community College Faculty
This interactive session explores ways in which an academic division at a community college developed a program of faculty development and evaluation. We will discuss teaching evaluations for faculty, mentoring in preparation for tenure, and the support system provided to mentors
Test-retest repeatability of organ uptake on PSMAâtargeted 18FâDCFPyL PET/CT in patients with prostate cancer
Objectives
We evaluated 18F-DCFPyL testâretest repeatability of uptake in normal organs.
Methods
Twenty-two prostate cancer (PC) patients underwent two 18F-DCFPyL PET scans within 7 days within a prospective clinical trial (NCT03793543). In both PET scans, uptake in normal organs (kidneys, spleen, liver, and salivary and lacrimal glands) was quantified. Repeatability was determined by using within-subject coefficient of variation (wCOV), with lower values indicating improved repeatability.
Results
For SUVmean, repeatability was high for kidneys, spleen, liver, and parotid glands (wCOV, range: 9.0%â14.3%) and lower for lacrimal (23.9%) and submandibular glands (12.4%). For SUVmax, however, the lacrimal (14.4%) and submandibular glands (6.9%) achieved higher repeatability, while for large organs (kidneys, liver, spleen, and parotid glands), repeatability was low (range: 14.1%â45.2%).
Conclusion
We found acceptable repeatability of uptake on 18F-DCFPyL PET for normal organs, in particular for SUVmean in the liver or parotid glands. This may have implications for both PSMA-targeted imaging and treatment, as patient selection for radioligand therapy and standardized frameworks for scan interpretation (PROMISE, E-PSMA) rely on uptake in those reference organs
Lack of repeatability of radiomic features derived from PET scans: results from a 18FâDCFPyL testâretest cohort
Objectives
PET-based radiomic metrics are increasingly utilized as predictive image biomarkers. However, the repeatability of radiomic features on PET has not been assessed in a testâretest setting. The prostate-specific membrane antigen-targeted compound 18F-DCFPyL is a high-affinity, high-contrast PET agent that we utilized in a test-retest cohort of men with metastatic prostate cancer (PC).
Methods
Data of 21 patients enrolled in a prospective clinical trial with histologically proven PC underwent two 18F-DCFPyL PET scans within 7 days, using identical acquisition and reconstruction parameters. Sites of disease were segmented and a set of 29 different radiomic parameters were assessed on both scans. We determined repeatability of quantification by using Pearson's correlations, within-subject coefficient of variation (wCOV), and BlandâAltman analysis.
Results
In total, 230 lesions (177 bone, 38 lymph nodes, 15 others) were assessed on both scans. For all investigated radiomic features, a broad range of inter-scan correlation was found (r, 0.07â0.95), with acceptable reproducibility for entropy and homogeneity (wCOV, 16.0% and 12.7%, respectively). On BlandâAltman analysis, no systematic increase or decrease between the scans was observed for either parameter (±1.96âSD: 1.07/â1.30, 0.23/â0.18, respectively). The remaining 27 tested radiomic metrics, however, achieved unacceptable high wCOV (â„21.7%).
Conclusion
Many common radiomic features derived from a testâretest PET study had poor repeatability. Only Entropy and homogeneity achieved good repeatability, supporting the notion that those image biomarkers may be incorporated in future clinical trials. Those radiomic features based on high frequency aspects of images appear to lack the repeatability on PET to justify further study
High SUVs have more robust repeatability in patients with metastatic prostate cancer: results from a prospective test-retest cohort imaged with 18F-DCFPyL
OBJECTIVES: In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged with (18)F-DCFPyL. METHODS: In this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent two (18)F-DCFPyL PET/CTs within 7 days (mean 3.7, range 1 to 7 days). Lesions in the bone, lymph nodes (LN), and other organs were manually segmented on both scans, and uptake parameters were assessed (maximum (SUV(max)) and mean (SUV(mean)) SUVs), PSMA-tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA, defined as PSMA â TV Ă SUV(mean))). Repeatability was determined using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland-Altman analysis. RESULTS: In total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUV(max) (1.5â80.5) and SUV(mean) (1.4â24.8). Including all sites of suspected disease, SUVs had a strong interscan correlation (R(2) â„ 0.99), with high repeatability for SUV(mean) and SUV(max) (wCOV, 7.3% and 12.1%, respectively). High SUVs showed significantly improved wCOV relative to lower SUVs (P < 0.0001), indicating that high SUVs are more repeatable, relative to the magnitude of the underlying SUV. Repeatability for PSMA-TV and TL-PSMA, however, was low (wCOV â„ 23.5%). Across all metrics for LN and bone lesions, interscan correlation was again strong (R(2) â„ 0.98). Moreover, LN-based SUV(mean) also achieved the best wCOV (3.8%), which was significantly reduced when compared to osseous lesions (7.8%, P < 0.0001). This was also noted for SUV(max) (wCOV, LN 8.8% vs. bone 12.0%, P < 0.03). On a compartment-based level, wCOVs for volumetric features were â„22.8%, demonstrating no significant differences between LN and bone lesions (PSMA-TV, Pâ=0.63; TL-PSMA, Pâ=0.9). Findings on an entire tumor burden level were also corroborated in a hottest lesion analysis investigating the SUV(max) of the most intense lesion per patient (R(2), 0.99; wCOV, 11.2%). CONCLUSION: In this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability
Double-dual n-types over Banach spaces not containing â1
Let E be a Banach space. The concept of n-type overE is introduced here, generalizing the concept of type overE introduced by Krivine and Maurey. Let Eâł be the second dual of E and fix gâł1,âŠgâłnâEâł. The function Ï:EĂânââ, defined by letting Ï(x,a1,âŠ,an)=âx+âi=1naigâłiâ for all xâE and all a1,âŠ,anââ, defines an n-type over E. Types that can be represented in this way are called double-dual n-types; we say that (gâł1,âŠgâłn)â(Eâł)n realizes Ï. Let E be a (not necessarily separable) Banach space that does not contain â1. We study the set of elements of (Eâł)n that realize a given double-dual n-type over E. We show that the set of realizations of this n-type is convex. This generalizes a result of Haydon and Maurey who showed that the set of realizations of a given 1-type over a separable Banach space E is convex. The proof makes use of Henson's language for normed space structures and uses ideas from mathematical logic, most notably the Löwenheim-Skolem theorem
Double-dual types over the Banach space C(K)
Let K be a compact Hausdorff space and C(K) the Banach space
of all real-valued continuous functions on K, with the sup-norm.
Types over C(K) (in the sense of Krivine and Maurey) can be
uniquely represented by pairs (â,u) of bounded real-valued
functions on K, where â is lower semicontinuous, u is upper semicontinuous, ââ€u, and â(x)=u(x) for all
isolated points x of K. A condition that characterizes the pairs (â,u) that represent double-dual types over C(K) is given
Types Over Banach Spaces
187 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000.We give a characterization of Banach lattice types over L p(O, U , mu) in terms of conditional distributions.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD