Positron Systems (United States)

Prostate-specific membrane antigen (PSMA)-targeted radiopharmaceutical therapy (RPT) is a safe and well-tolerated treatment option for metastatic, castration-resistant prostate cancer (mCRPC). A new radioligand, comprising ibuprofen as an albumin-binding entity, [177Lu]Lu-SibuDAB, demonstrated an increased tumour-absorbed dose and efficacy in preclinical studies while tumour-to-organ absorbed dose coefficient ratios were similar to conventional PSMA radiopharmaceuticals. We conducted a translational study to evaluate response rate, safety and efficacy, and quality of life of [177Lu]Lu-Sibu-DAB in progressive mCRPC patients. From July 2021 to January 2023 a total of seventeen eligible patients, sixteen (median age 71 years, range 63-83) were selected to receive up to four cycles of [177Lu]Lu-SibuDAB at an activity of 4.3 to 5.9 GBq (median 5.3 GBq). The response rate was assessed by serum prostate specific antigen (PSA) and by PET/CT using [18F]PSMA-1007, at baseline and post-therapeutic up to eight weeks, using RECIP 1.0 criteria. Safety and adverse events were investigated clinically by analyzing serial blood biomarkers and the recording of adverse events according to CTCAE v5.0. Quality of life was assessed by the European Organization for Research and Treatment of Cancer Core Quality of Life (EORTC) questionnaires QLQ-C30 and QLQ-PR25. Seven participants received 4 cycles of [177Lu]Lu-SibuDAB, 3 participants received 3 cycles and 6 participants received ≤ 2 cycles because of disease progression or advanced stage of the disease. A maximum PSA decline (median baseline PSA value: 49.1 ng/ml (min 0,84 ng/ml max 145,1 ng/ml) by at least ≥ 50%, was observed in four participants, while stable serum PSA was observed in five further participants. Longitudinal PET/CT was performed with 10 participants, showing partial remission in five, stable disease in two and progressive disease in three patients. We observed an association between the changes in PSA levels and PET/CT-image-based assessment of the response. Two participants experienced grade three anaemia, one of them also a grade four thrombocytopenia. Two patients, heavily pre-treated with chemotherapy, experienced grade 3 thrombocytopenia. Impairment of renal or liver function was not observed. Importantly, no xerostomia was recorded for any of the participants. No significant changes in the quality of life were reported. Median overall survival was 13.9 months in this cohort. Overall survival and response rates of patients are consistent with previous reports on PSMA-targeted RPT while the absence of xerostomia can be considered an improvement. Up to four cycles of [177Lu]Lu-SibuDAB were well tolerated and [177Lu]Lu-SibuDAB appears to be a valid option for effective treatment of patients with progressive mCRPC. Randomized clinical trials to assess efficacy compared to established RPT are warranted.

In this article, we present our recent experiments on fission fragment rocket propulsion, and on an innovative new design for an alpha particle detection system that has been inspired by these rocketry results. Our test platform, which operates within high magnetic fields 3 T over a large cross$\unicode{x2013}$section (approximately 40 cm in diameter), has been used as a test platform to evaluate the containment and thrust within a future fission$\unicode{x2013}$fragment rocket engine (FFRE). This much more efficient nuclear rocket propulsion FFRE design was first proposed in the 1980s with the intent of greatly reducing transit times in long$\unicode{x2013}$duration space travel. Our objective is to enhance the operational efficiency of this nuclear rocket while gaining deeper insights into the behavior of fuel particles and of the fission$\unicode{x2013}$fragment ejecta within strong magnetic fields experimentally. Through a combination of simulations and experimental work, we established a method for the production and detection of alpha particles as a surrogate for fission fragments. To achieve this, we employed Americium$\unicode{x2013}$241 ($^{ 241}$Am) sources, which were situated within a cylindrical vacuum chamber positioned in a 3$\unicode{x2013}$T Siemens MRI superconducting magnet. By simulating, measuring, and analyzing the emitted alpha particle flux, we gained valuable information about the distribution and likelihood of escape of fission fragments in a future FFRE design. This approach could potentially achieve both high specific impulse and power density in advanced nuclear propulsion systems, such as the FFRE. More generally, this work provides a powerful new approach for analyzing ion flux and nuclear particle or nuclear reaction fragments from a wide variety of experimental designs.

Accumulated fatigue damage in flight critical helicopter dynamic components prior to crack initiation and detection is currently estimated by fatigue analysis based upon fatigue test results. To more accurately assess the operational fatigue damage and remaining useful life of a critical component prior to the initiation of a detectable crack, a non-destructive evaluation (NDE) process that directly measures accumulated fatigue damage is required. These NDE measurements are useful in monitoring accumulated fatigue damage, assessing probability of failure, determining remaining useful life, establishing inspection intervals, and refining fatigue damage accumulation models at any point in the operational life cycle of structural components. Induced positron analysis (IPA) was evaluated as an NDE technology to investigate the potential for safely extending the useful life of existing CH/MH-47 Chinook aft rotor shafts that are being retired upon reaching the operational flight hour limits as defined by current design life criteria. An IPA survey of the critical areas of a retired MH-47E shaft was conducted to determine if the IPA technology could reliably detect material degradation that would warrant application to a larger population of operational rotor shafts. The IPA NDE results profiled distinct material condition trends in the shaft upper spline tooth root, sidewall elevations, and top, for both the drive and non- drive sides (36 locations per spline tooth). IPA material damage measurements were successfully correlated with the local stress values as predicted by the OEM's finite element analysis (FEA) of the shaft spline. Additionally, IPA measurements axially along several teeth indicated no significant material degradation, despite a visible impression on the lower spline. This visible impression has been erroneously judged to be a wear-step and has resulted in unnecessary early retirement of serviceable rotor shafts. Based upon the success of the IPA evaluation of the initial MH-47E aft rotor shaft, more CH/MH-47 shafts, at varying stages of their operational life cycles, are programmed for IPA assessment.This paper will describe the underlying IPA technology, the initial MH-47E aft rotor shaft application and test results, the correlation of IPA with FEA results, the path ahead for further CH/MH-47 IPA NDE inspections, and the potential benefits of applying IPA NDE to the entire population of CH/MH-47 aft rotor shafts.

The ability to detect and quantify beneficial surface and subsurface residual stresses, and operational damage in aerospace materials/structures in a reliable and efficient manner presents significant challenges to existing nondestructive inspection technologies. Induced Positron Analysis (IPA) has demonstrated the ability to nondestructively quantify shot peening/surface treatments and relaxation effects in single crystal superalloys, steels, titanium and aluminum with a single measurement as part of a National Science Foundation SBIR program and in projects with commercial companies. IPA measurement of surface treatment effects provides a demonstrated ability to quantitatively measure initial treatment effectiveness along with the effect of operationally induced changes over the life of the treated component. Use of IPA to nondestructively quantify surface and subsurface residual stresses in turbine engine materials and components has the potential to significantly improve the understanding at the microscale level the effects of surface coatings and treatments on the durability and fatigue life of critical components.

Aging effects can have a significant consequence on the mission readiness of solid propellant rocket systems. A potential end result of grain cracking caused by aging is the catastrophic failure of the rocket motor. Propellant changes leading to grain cracking are an increase in cross -link density and/or induced dam age. The detection of this crack generating degradation within the solid propellant is critical. Initial manufacturing variability creates rocket motor assets with varying vulnerability to grain cracking. This significantly raises maintenance requirement s, reduces operational life times and threatens mission readiness. Several experimental methods are currently used to determine the cross link density of solid propellant. Unfortunately, these cross -link density measurement methods are all destructive te st determinations meaning the solid rocket propellant material must be dissected out of the main rocket asset for analysis. Dissection work is extremely expensive in terms of manpower, materials and money. Current non -destructive evaluation (NDE) and non -destructive inspection (NDI) techniques offer limited capability for the determination of cross -link density and/or induced damage. Photon Induced Positron Annihilation (PIPA) has demonstrated that non -destructive results on strain buildup and grain crac king in solid rocket propellant can be determined using the PIPA technique and that propellant damage could be detected using this technique through the rocket case of actual rocket systems, which could result in accurate and reliable assessments of compon ent readiness either at the manufacturing level or during field inspections. This NDI process will provide reliable material damage characterization including the buildup of defects and changes in the atomic structure of the propellant without disassembly and at detection levels below current NDI methods.

<div class="htmlview paragraph">Advanced materials including metal matrix, ceramic metal matrix and other composites/metals are critical to numerous applications associated with the development of next-generation aircraft architectures whose goal is to produce aerospace platforms that are more cost efficient, safe and reliable. The wide variety of advanced materials used in aerospace construction creates significant challenges for existing material characterization technologies. Photon Induced Positron Annihilation and related technologies are currently being used to assess fatigue, thermal degradation, creep, and embrittlement in aircraft components composed of advanced composite and metal alloy materials from initial manufacture through failure, thereby providing a new reliability assessment tool for pre- and post-mission component evaluations and likelihood-of-failure assessments.</div>

Development of reliable performance life remaining prognostic models for aircraft turbine engine components such as disks and blades requires accurate diagnostic methods to measure integrated damage effects with uncertainties. Photon induced positron annihilation (PIPA) and related technologies have demonstrated the capability to accurately and quantitatively measure operational damage accumulation in turbine engine components that can be used to develop mechanistic failure models that would be applicable to current engine prognostic models. Quantitative failure models for operational components that are based on the PIPA measurement data are expected to have a high degree of accuracy and provide suitable statistical data on the likelihood of failure for any given period of operation. Results of PIPA studies performed as part of National Science Foundation and other studies that assess the relative effects of surface treatments, temperature, fatigue, and thermomechanical damage on nickel based superalloy components indicate that damage effects in turbine engine components can be quantified and incorporated in appropriate life remaining models.

Hydro-Quebec's experience with polymer insulators began in 1977. A sixteen km section of a 735 kV transmission line near Quebec City was then re-insulated with 282 composite insulators of three different makes in equal proportions. The objective was to study them under real service conditions in order to evaluate their performance and to assess the relative merits of each make. This experimentation was later extended to some other lines and/or voltage levels and has continued up to now. During all these years, various methods of testing composite insulators in-service have been experimented with and early in the 1990s, the first device developed at IREQ for the in-situ testing of porcelain insulators by the electric field method was modified and adapted for use on composite suspension insulators. This paper presents a few cases of insulators having a particularly dangerous type of failure mode and found on the lines by the use of the electric field method. Some background information on the detection of defects by this method is also given and some of the experiments done in the laboratory on composite insulators to define the limits of the method are described.

This document describes an architecture for describing SNMP Management Frameworks. The architecture is designed to be modular to allow the evolution of the SNMP protocol standards over time. The major portions of the architecture are an SNMP engine containing a Message Processing Subsystem, a Security Subsystem and an Access Control Subsystem, and possibly multiple SNMP applications which provide specific functional processing of management data.