Properties of the 5- state at 839 keV in 176Lu and the s-process branching at A = 176

The s-process branching at mass number A = 176 depends on the coupling between the high-K ground state and a low-lying low-K isomer in 176Lu. This coupling is based on electromagnetic transitions via intermediate states at higher energies. The properties of the lowest experimentally confirmed intermediate state at 839 keV are reviewed, and the transition rate between low-K and high-K states under stellar conditions is calculated on the basis of new experimental data for the 839 keV state. Properties of further candidates for intermediate states are briefly analyzed. It is found that the coupling between the high-K ground state and the low-K isomer in 176Lu is at least one order of magnitude stronger than previously assumed leading to crucial consequences for the interpretation of the 176Lu/176Hf pair as an s-process thermometer.Comment: 11 pages, 4 figures accepted for publication in Phys. Rev.

Stereotactic Robotic Body Radiotherapy for Patients With Unresectable Hepatic Oligorecurrence

Micro-Abstract We present our retrospective study of 42 patients treated for hepatic oligorecurrence with stereotactic body radiotherapy using the CyberKnife system (Accuray Inc). Besides reporting on acute and late toxicities, the influence of patient and lesion characteristics on local control, liver and distant progression-free survival, and overall survival were also investigated. Background The purpose of this study was to analyze local control (LC), liver progression-free survival (PFS), and distant PFS (DFS), overall survival (OS), and toxicity in a cohort of patients treated with stereotactic body radiotherapy (SBRT) with fiducial tracking for oligorecurrent liver lesions; and to evaluate the potential influence of lesion size, systemic treatment, physical and biologically effective dose (BED), treatment calculation algorithms and other parameters on the obtained results. Patients and Methods Unoperable patients with sufficient liver function had [18F]-fluorodeoxyglucose-positron emission tomography-computed tomography and liver magnetic resonance imaging to confirm the oligorecurrent nature of the disease and to further delineate the gross tumor volume (GTV). An intended dose of 45 Gy in 3 fractions was prescribed on the 80% isodose and adapted if risk-related. Treatment was executed with the CyberKnife system (Accuray Inc) platform using fiducials tracking. Initial plans were recalculated using the Monte Carlo algorithm. Patient and treatment data were processed using the Kaplan–Meier method and log rank test for survival analysis. Results Between 2010 and 2015, 42 patients (55 lesions) were irradiated. The mean GTV and planning target volume (PTV) were 30.5 cc and 96.8 cc, respectively. Treatments were delivered 3 times per week in a median of 3 fractions to a PTV median dose of 54.6 Gy. The mean GTV and PTV D98% were 51.6 Gy and 51.2 Gy, respectively. Heterogeneity corrections did not influence dose parameters. After a median follow-up of 18.9 months, the 1- and 2-year LC/liver PFS/DFS/OS were 81.3%/55%/62.4%/86.9%, and 76.3%/42.3%/52%/78.3%, respectively. Performance status and histology had a significant effect on LC, whereas age (older than 65 years) marginally influenced liver PFS. Clinical target volume physical dose V45 Gy > 95%, generalized equivalent uniform dose (a = −30) > 45 Gy and a BED (α/β = 10) V105 Gy > 96% showed statistically significant effect on the LC. Acute Grade 3 gastrointestinal (GI) and late Grade 2 GI and fatigue toxicity were found in 5% and 11% patients, respectively. Conclusion Favorable survival and toxicity results support the potential paradigm shift in which the use of SBRT in oligorecurrent liver disease could benefit patients with unresectable or resectable liver metastases. © 2017 Elsevier Inc