Shortened Tracer Uptake Time in GA-68-DOTATOC-PET of Meningiomas Does Not Impair Diagnostic Accuracy and PET Volume Definition

Ga-68-DOTATOC-PET/MRI can affect the planning target volume (PTV) definition of meningiomas before radiosurgery. A shorter tracer uptake time before image acquisition could allow the examination of more patients. The aim of this study was to investigate if shortening uptake time is possible without compromising diagnostic accuracy and PET volume. Fifteen patients (f = 12; mean age 52 years (34-80 years)) with meningiomas were prospectively examined with dynamic [68Ga]Ga-68-labeled [DOTA0-Phe1-Tyr3] octreotide (Ga-68-DOTATOC)-PET/MRI over 70 min before radiosurgery planning. Meningiomas were delineated manually in the PET dataset. PET volumes at each time point were compared to the reference standard 60 min post tracer injection (p.i.) using the Friedman test followed by a Wilcoxon signed-rank test and Bonferroni correction. In all patients, the earliest time point with 100% lesion detection compared to 60 min p.i. was identified. PET volumes did not change significantly from 15 min p.i. (p = 1.0) compared to 60 min p.i. The earliest time point with 100% lesion detection in all patients was 10 min p.i. In patients with meningiomas undergoing Ga-68-DOTATOC-PET, the tracer uptake time can safely be reduced to 15 min p.i. with comparable PET volume and 100% lesion detection compared to 60 min p.i

Bound -state β- -decay of bare 205 Tl 81+

Beta decay into bound electron states of the daughter atom accompanied by the emission of a monochromatic antineutrino, has been predicted by Daudel et al.[1]. However, a noteworthy probability of βb- decay exists only for highly-charged ions, which makes its observation rather difficult

Status and New Data of the Geochemical Determination of the pp-Neutrino Flux by LOREX

LOREX LORandite EXperiment addresses the determination of the solar pp neutrino flux during the last four million years by exploiting the reaction 205 Tl ν e → 205 Pb e − with an incomparably low-energy threshold of 50 keV for the capture of solar neutrinos. The ratio of 205 Pb/ 205 Tl atoms in the Tl-bearing mineral lorandite provides, if corrected for the cosmic-ray induced background, the product of the flux of solar neutrinos and their capture probability by 205 Tl, averaged over the age of lorandite. To get the mean solar neutrino flux itself, four problems have to be addressed: 1 the geological age of lorandite, 2 the amount of background cosmicray-induced 205 Pb atoms which strongly depends on the erosion rate of the lorandite-bearing rocks, 3 the capture probability of solar neutrinos by 205 Tl and 4 the extraction of lorandite and the appropriate technique to "count" the small number of 205 Pb atoms in relation to the number of 205 Tl atoms. This paper summarizes the status of items 1 age and 3 neutrino capture probability and presents in detail the progress achieved most recently concerning the items 2 background/erosion and 4 "counting" of 205 Pb atoms in lorandite

Hybrid SPECT/CT for the assessment of a painful hip after uncemented total hip arthroplasty

Background The diagnosis of hip pain after total hip replacement (THR) represents a highly challenging question that is of increasing concern to orthopedic surgeons. This retrospective study assesses bone scintigraphy with Hybrid SPECT/CT for the diagnosis of painful THR in a selected cohort of patients. Methods Bone SPECT/CT datasets of 23 patients (mean age 68.9 years) with a painful hip after THR were evaluated. Selection of the patients required an inconclusive radiograph, normal serum levels of inflammatory parameters (CRP and ESR) or a negative aspiration of the hip joint prior to the examination. The standard of reference was established by an interdisciplinary adjudication-panel using all imaging data and clinical follow-up data (>12 month). Pathological and physiological uptake patterns were defined and applied. Results The cause of pain in this study group could be determined in 18 out of 23 cases. Reasons were aseptic loosening (n = 5), spine-related (n = 5), heterotopic ossification (n = 5), neuronal (n = 1), septic loosening (n = 1) and periprosthetic stress fracture (n = 1). In (n = 5) cases the cause of hip pain could not be identified. SPECT/CT imaging correctly identified the cause of pain in (n = 13) cases, in which the integrated CT-information led to the correct diagnosis in (n = 4) cases, mainly through superior anatomic correlation. Loosening was correctly assessed in all cases with a definite diagnosis. Conclusions SPECT/CT of THA reliably detects or rules out loosening and provides valuable information about heterotopic ossifications. Furthermore differential diagnoses may be detected with a whole-body scan and mechanical or osseous failure is covered by CT- imaging. SPECT/CT holds great potential for imaging-based assessment of painful prostheses

Preventive medicine of von Hippel-Lindau disease-associated pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations. Of 2330 VHL patients, 273 had a total of 484 PanNETs. Median age at diagnosis of PanNET was 35 years (range 10-75). Fifty-five (20%) patients had metastatic PanNETs. Metastatic PanNETs were significantly larger (median size 5 vs 2\u2009cm; P\u20091.5\u2009cm in diameter were operated. Ten-year survival was significantly longer in operated vs non-operated patients, in particular for PanNETs <2.8\u2009cm vs 652.8\u2009cm (94% vs 85% by 10 years; P\u2009=\u20090.020; 80% vs 50% at 10 years; P\u2009=\u20090.030). This study demonstrates that patients with PanNET approaching the cut-off diameter of 2.8\u2009cm should be operated. Mutations in exon 3, especially of codons 161/167 are at enhanced risk for metastatic PanNETs. Survival is significantly longer in operated non-metastatic VHL-PanNETs