THE HOLOGRAPHIC DETECTOR FOR CLOUDS FROM TRL 5 TO TRL 8

Clouds are one of the most influential elements of weather on the earth system, yet they are also one of the least understood. Understanding their composition and behavior at small scales is critical to understanding and predicting larger scale feedbacks. Currently, the best method to study clouds on the microscale is through airborne in situ measurements using optical instruments capable of resolving clouds on the individual particle level. However, current instruments are unable to sufficiently resolve the scales important to cloud evolution and behavior. The Holodec is a new generation of optical cloud instrument which uses digital inline holography to overcome many of the limitations of conventional instruments. However, its performance and reliability was limited due to several deficiencies in its original design. These deficiencies were addressed and corrected to advance the instrument from the prototype stage to an operational instrument. In addition, the processing software used to reconstruct and analyze digitally recorded holograms was improved upon to increase robustness and ease of use.

Evaluation of a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-conjugated bombesin-based radioantagonist for the labeling with single-photon emission computed tomography, positron emission tomography, and therapeutic radionuclides

PURPOSE: G protein-coupled receptor agonists are being used as radiolabeled vectors for in vivo localization and therapy of tumors. Recently, somatostatin-based antagonists were shown to be superior to agonists. Here, we compare the new [111In/68Ga]-labeled bombesin-based antagonist RM1 with the agonist [111In]-AMBA for targeting the gastrin-releasing peptide receptor (GRPR). EXPERIMENTAL DESIGN: IC50, Kd values, and antagonist potency were determined using PC-3 and HEK-GRPR cells. Biodistribution and imaging studies were done in nude mice transplanted with the PC-3 tumor. The antagonist potency was assessed by evaluating the effects on calcium release and on receptor internalization monitored by immunofluorescence microscopy. RESULTS: The IC50 value of [(nat)In]-RM1 was 14 +/- 3.4 nmol/L. [(nat/111)In]-RM1 was found to bind to the GRPR with a Kd of 8.5 +/- 2.7 nmol/L compared with a Kd of 0.6 +/- 0.3 nmol/L of [111In]-AMBA. A higher maximum number of binding site value was observed for [111In]-RM1 (2.4 +/- 0.2 nmol/L) compared with [111In]-AMBA (0.7 +/- 0.1 nmol/L). [(nat)Lu]-AMBA is a potent agonist in the immunofluorescence-based internalization assay, whereas [(nat)In]-RM1 is inactive alone but efficiently antagonizes the bombesin effect. These data are confirmed by the calcium release assay. The pharmacokinetics showed a superiority of the radioantagonist with regard to the high tumor uptake (13.4 +/- 0.8% IA/g versus 3.69 +/- 0.75% IA/g at 4 hours after injection. as well as to all tumor-to-normal tissue ratios. CONCLUSION: Despite their relatively low GRPR affinity, the antagonists [111In/68Ga]-RM1 showed superior targeting properties compared with [111In]-AMBA. As found for somatostatin receptor-targeting radiopeptides, GRP-based radioantagonists seem to be superior to radioagonists for in vivo imaging and potentially also for targeted radiotherapy of GRPR-positive tumors.

Thoracolumbar spine fractures in patients who have sustained severe trauma: depiction with multi-detector row CT

PURPOSE: To determine if multi–detector row computed tomography (CT) can replace conventional radiography and be performed alone in severe trauma patients for the depiction of thoracolumbar spine fractures. MATERIALS AND METHODS: One hundred consecutive severe trauma patients who underwent conventional radiography of the thoracolumbar spine as well as thoracoabdominal multi–detector row CT were prospectively identified. Conventional radiographs were reviewed independently by three radiologists and two orthopedic surgeons; CT images were reviewed by three radiologists. Reviewers were blinded both to one another’s reviews and to the results of initial evaluation. Presence, location, and stability of fractures, as well as quality of reviewed images, were assessed. Statistical analysis was performed to determine sensitivity and interobserver agreement for each procedure, with results of clinical and radiologic follow-up as the standard of reference. The time to perform each examination and the radiation dose involved were evaluated. A resource cost analysis was performed. RESULTS: Sixty-seven fractured vertebrae were diagnosed in 26 patients. Twelve patients had unstable spine fractures. Mean sensitivity and interobserver agreement, respectively, for detection of unstable fractures were 97.2% and 0.951 for multi–detector row CT and 33.3% and 0.368 for conventional radiography. The median times to perform a conventional radiographic and a multi–detector row CT examination, respectively, were 33 and 40 minutes. Effective radiation doses at conventional radiography of the spine and thoracoabdominal multi–detector row CT, respectively, were 6.36 mSv and 19.42 mSv. Multi–detector row CT enabled identification of 146 associated traumatic lesions. The costs of conventional radiography and multi–detector row CT, respectively, were $145 and $880 per patient. CONCLUSION: Multi–detector row CT is a better examination for depicting spine fractures than conventional radiography. It can replace conventional radiography and be performed alone in patients who have sustained severe trauma.

Expected performance of the ATLAS experiment - detector, trigger and physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

Triggering on Long-Lived Neutral Particles in the ATLAS Detector

Neutral particles with long decay paths that decay to many-particle final states represent, from an experimental point of view, a challenge both for the trigger and for the reconstruction capabilities of the ATLAS apparatus. The Hidden Valley scenario serves as an excellent setting for the purpose of exploring the challenges to the trigger posed by long-lived particles.