DETERMINATION OF COLLECTION EFFICIENCY OF ATMOSPHERIC IONS BY THE SYSTEMS OF PARALLEL CONDUCTIVE PLATES

We present a theory that describes the scenarios of equations of motion of clustered air ions entering into specific systems. The system analyzed here is composed by two or three conductive parallel plates. In the first case (system of two parallel plates) one plate collects air ions which enter into the area between these plates. In the second case (system of three parallel plates) the collector plate is the middle one.Air ions usually are classified into several categories according to their electrical mobility (size). The main categories are: cluster ions (mobility 0.5-3.2 cm2/V.s), intermediate ions (mobility 0.034-0.5 cm2/V.s), and large ions (mobility 0.0042-0.034 cm2/V.s).This theory has an important application on ion counter operations. Usually the apparatus measures the concentrations of only cluster air ions (mobility > 0.5 cm2/V.s). Air ions are deflected by the electric field established by a potential difference of polarized plates. Air ion concentrations are derived from measurement of electrical current caused in the system.Based on this theory, we can determine analytically the efficiency of the collection of air ions of different electrical mobility by above mentioned systems

Early Photography in Albania The Photographic Legacy of Kol Idromeno

Kol Idromeno, (1860-1939) was one of the foremost artists of AlbanianRenaissance art. Idromeno was a distinguished painter, architect, photographer, scenographer, sculptor, artisan etc. He is mostly known as a painter and architect. His achievements in these two fields have overshadowed somehow his also remarkable efforts in other arts. Especially his photographic heritage is of particular interest. He began his photographic activity in 1886 after he attended at the Marubbi studio, which was the first photographic studio in Albania. Idromeno started his career as a photographer, working with the wet collodion process. By 1899 Idromeno had switched to the dry gelatin plates.The main body of his photographic work is preserved in the archives of QSA (Qendra e Studimeve Albanologjike – Center for Albanological Studies ) in Tirana. There are 1285 glass negatives in this archive. There are about 150 more negatives in the Marubi National Museum of Photography in Shkodra. Portraits and group portraits are the most numerous among all other genres. These portraits represent an important exposé of Albanian society between the 19th and 20th centuries. Men, women, children, officials, aristocrats, highlanders, soldiers, merchants, priests, lay people, they all go through the photographer‘s lens. The photography of architecture, streets and urban ensembles is especially dear to Idromeno. Being also an architect, architecture would be one of the favorite subjects. In the historic photography context, there are dozens of photographs representing many sorts of soldiers, officers, and armies. Idromeno lived in a very turbulent period of Albanian history. The Albanian struggle for independence, the Balkan Wars, and the First World War. Artistic effort can be observed in all genres of his photography. Being also a painter he used the correlation painting-photography primarily to the advantage of the first. However, some of the photographs used as a preparatory material for painting, reveal today genuine examples of fine art photography.Keywords: Visual art, art history, photography, ethnography, Albanology

Walking With the ISMRM in the Footprints of Our MR History

The International Society for Magnetic Resonance in Medicine (ISMRM) has undoubtedly played a central role in helping shape our field. In particular, the annual meetings have been an avenue of choice for presenting new MR methods, tools, and applications of aspects of our field that have greatly impacted and transformed how MR is used today, and those abstracts have become “classic” contributions to our field. In 1994, the ISMRM (or SMR, as it was named at the time) was formed from the joining of the Society for Magnetic Resonance in Medicine (SMRM) and the Society for Magnetic Resonance Imaging (SMRI), which originated in 1982. In those early years, MR was a nascent technology and many of the sequences, analysis tools, and hardware applications we take for granted today had not yet been conceived. Now, as a celebration of the 40th anniversary of these annual meetings, we walk in the “footprints” of the ISMRM and its predecessor Societies: we look back at some of the classic abstracts presented at the annual meetings, reflect on this long history with some of its early members, and report on the Special Session held to celebrate the occasion at the 2022 Annual Meeting in London

Real-time myocardial landmark tracking for MRI-guided cardiac radio-ablation using Gaussian Processes

The high speed of cardiorespiratory motion introduces a unique challenge for cardiac stereotactic radio-ablation (STAR) treatments with the MR-linac. Such treatments require tracking myocardial landmarks with a maximum latency of 100 ms, which includes the acquisition of the required data. The aim of this study is to present a new method that allows to track myocardial landmarks from few readouts of MRI data, thereby achieving a latency sufficient for STAR treatments. We present a tracking framework that requires only few readouts of k-space data as input, which can be acquired at least an order of magnitude faster than MR-images. Combined with the real-time tracking speed of a probabilistic machine learning framework called Gaussian Processes, this allows to track myocardial landmarks with a sufficiently low latency for cardiac STAR guidance, including both the acquisition of required data, and the tracking inference. The framework is demonstrated in 2D on a motion phantom, and in vivo on volunteers and a ventricular tachycardia (arrhythmia) patient. Moreover, the feasibility of an extension to 3D was demonstrated by in silico 3D experiments with a digital motion phantom. The framework was compared with template matching - a reference, image-based, method - and linear regression methods. Results indicate an order of magnitude lower total latency (<10 ms) for the proposed framework in comparison with alternative methods. The root-mean-square-distances and mean end-point-distance with the reference tracking method was less than 0.8 mm for all experiments, showing excellent (sub-voxel) agreement. The high accuracy in combination with a total latency of less than 10 ms - including data acquisition and processing - make the proposed method a suitable candidate for tracking during STAR treatments

Brain and Head-and-Neck MRI in Immobilization Mask: A Practical Solution for MR-Only Radiotherapy

In brain/head-and-neck radiotherapy (RT), thermoplastic immobilization masks guarantee reproducible patient positioning in treatment position between MRI, CT, and irradiation. Since immobilization masks do not fit in the diagnostic MR head/head-and-neck coils, flexible surface coils are used for MRI imaging in clinical practice. These coils are placed around the head/neck, in contact with the immobilization masks. However, the positioning of these flexible coils is technician dependent, thus leading to poor image reproducibility. Additionally, flexible surface coils have an inferior signal-to-noise-ratio (SNR) compared to diagnostic coils. The aim of this work was to create a new immobilization setup which fits into the diagnostic MR coils in order to enhance MR image quality and reproducibility. For this purpose, a practical immobilization setup was constructed. The performances of the standard clinical and the proposed setups were compared with four tests: SNR, image quality, motion restriction, and reproducibility of inter-fraction subject positioning. The new immobilization setup resulted in 3.4 times higher SNR values on average than the standard setup, except directly below the flexible surface coils where similar SNR was observed. Overall, the image quality was superior for brain/head-and-neck images acquired with the proposed RT setup. Comparable motion restriction in feet-head/left-right directions (maximum motion ≈1 mm) and comparable inter-fraction repositioning accuracy (mean inter-fraction movement 1 ± 0.5 mm) were observed for the standard and the new setup

STereotactic Arrhythmia Radioablation (STAR): the Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary consortium (STOPSTORM.eu) and review of current patterns of STAR practice in Europe

The EU Horizon 2020 Framework-funded Standardized Treatment and Outcome Platform for Stereotactic Therapy Of Re-entrant tachycardia by a Multidisciplinary (STOPSTORM) consortium has been established as a large research network for investigating STereotactic Arrhythmia Radioablation (STAR) for ventricular tachycardia (VT). The aim is to provide a pooled treatment database to evaluate patterns of practice and outcomes of STAR and finally to harmonize STAR within Europe. The consortium comprises 31 clinical and research institutions. The project is divided into nine work packages (WPs): (i) observational cohort; (ii) standardization and harmonization of target delineation; (iii) harmonized prospective cohort; (iv) quality assurance (QA); (v) analysis and evaluation; (vi, ix) ethics and regulations; and (vii, viii) project coordination and dissemination. To provide a review of current clinical STAR practice in Europe, a comprehensive questionnaire was performed at project start. The STOPSTORM Institutions' experience in VT catheter ablation (83% ≥ 20 ann.) and stereotactic body radiotherapy (59% > 200 ann.) was adequate, and 84 STAR treatments were performed until project launch, while 8/22 centres already recruited VT patients in national clinical trials. The majority currently base their target definition on mapping during VT (96%) and/or pace mapping (75%), reduced voltage areas (63%), or late ventricular potentials (75%) during sinus rhythm. The majority currently apply a single-fraction dose of 25 Gy while planning techniques and dose prescription methods vary greatly. The current clinical STAR practice in the STOPSTORM consortium highlights potential areas of optimization and harmonization for substrate mapping, target delineation, motion management, dosimetry, and QA, which will be addressed in the various WPs