Magnetic Resonance Thermometry at 7T for Real-Time Monitoring and Correction of Ultrasound Induced Mild Hyperthermia

While Magnetic Resonance Thermometry (MRT) has been extensively utilized for non-invasive temperature measurement, there is limited data on the use of high field (≥7T) scanners for this purpose. MR-guided Focused Ultrasound (MRgFUS) is a promising non-invasive method for localized hyperthermia and drug delivery. MRT based on the temperature sensitivity of the proton resonance frequency (PRF) has been implemented in both a tissue phantom and in vivo in a mouse Met-1 tumor model, using partial parallel imaging (PPI) to speed acquisition. An MRgFUS system capable of delivering a controlled 3D acoustic dose during real time MRT with proportional, integral, and derivative (PID) feedback control was developed and validated. Real-time MRT was validated in a tofu phantom with fluoroptic temperature measurements, and acoustic heating simulations were in good agreement with MR temperature maps. In an in vivo Met-1 mouse tumor, the real-time PID feedback control is capable of maintaining the desired temperature with high accuracy. We found that real time MR control of hyperthermia is feasible at high field, and k-space based PPI techniques may be implemented for increasing temporal resolution while maintaining temperature accuracy on the order of 1°C

A Scoping Review of Home Produced Heroin and Amphetamine Type Stimulant Substitutes: Implications for Prevention, Treatment and Policy

Several home-produced substances such as krokodil and boltushka are prevalent in many Eastern European countries. Anecdotal reports of its use have been circulating in Germany and Norway; however, this has not been confirmed. Its use has also been reported by the media in the USA, although only one confirmed report of its use exists. Home-produced drugs are associated with high levels of morbidity and a number of complex health issues such as the spread of blood borne viruses, gangrene, and internal organ damage. The high incidence of HIV rates amongst people who inject home-produced substances is a public health concern. The resulting physical health consequences of injecting these crude substances are very severe in comparison to heroin or amphetamine acquired in black markets. Due to this fact and the increased mortality associated with these substances, professionals in the area of prevention, treatment, and policy development need to be cognisant of the presentation, harms, and the dangers associated with home-produced substances globally. This scoping review aimed to examine existing literature on the subject of home-produced heroin and amphetamine-type stimulant substitutes. The review discussed the many implications such research may have in the areas of policy and practice. Data were gathered through the use of qualitative secondary resources such as journal articles, reports, reviews, case studies, and media reports. The home production of these substances relies on the utilisation of precursor drugs such as less potent stimulants, tranquillizers, analgesics, and sedatives or natural plant ingredients. The Internet underpins the facilitation of this practice as recipes, and diverted pharmaceutical sales are available widely online, and currently, ease of access to the Internet is evident worldwide. This review highlights the necessity of prevention, education, and also harm reduction related to home-produced drugs and also recommends consistent monitoring of online drug fora, online drug marketplaces, and unregulated pharmacies

Multiparticle 3D imaging technique to study the structure of molecular ions

When energetic molecular ions (E/sub ion/ = 0.1 to 0.5 MeV/amu) pass through thin solid targets a Coulomb explosion ensues due to the rapid (approx. 10/sup -17/s) stripping of the valence electrons. This process has been successfully used to derive stereochemical information on diatomic and on selected triatomic ions. In order to investigate more complex molecular ions as well as to obtain more accurate and detailed structure information, a large area, multiparticle, position- and time-sensitive detector has been developed to detect all atomic fragments in coincidence. The requirement of multiparticle detection independent of the relative particle positions leads to a rather complex data-readout and -reduction system containing approx. 650 analog-to-digital conversions per event. The system relies heavily on techniques developed for high energy physics experiments during recent years. The single event resolution of the apparatus with respect to bond-lengths and -angles has been studied by Monte Carlo simulations and is typically a few percent

Physics with fast molecular ions

Argonne's 5-MV Dynamitron accelerator is currently being used to study the interactions of fast (MeV) atomic and molecular ions with matter. The present emphasis of the work is upon the problem of determining the stereochemical structures of molecular-ion projectiles. The technique is based upon the ''Coulomb explosion'' of these projectiles when they strike a thin-foil target. By making careful determinations of the momenta of all of the fragments emitted from these Coulomb explosions, one can infer the original configuration of the molecular constituents in the projectile and, in favorable cases, their vibrational motions. This technique is particularly useful for those cases where the more traditional spectroscopic approaches cannot be applied. During the past year, new ideas and developments in the Coulomb-explosion technique have come to fruition. Radically new multiparticle detectors have been developed and implemented. Extremely thin film targets have been produced which reduce the ''blurring'' effect of multiple scattering, and a low-excitation ion source has been installed. These developments have resulted in direct measurements of the complete stereostructures of several small polyatomic molecular ions. In this paper we describe the experimental techniques, discuss some of the difficulties, and present some recent results. 19 refs., 5 figs

Molecular structure studies by 3D imaging of fast ion beams

The use of the Coulomb-explosion technique combined with a radically new multi-particle detector, extremely thin film targets, and low-excitation ion source has enabled, for the first time, direct measurements of the complete stereochemistry of complex polyatomic molecular ions. We outline the methods used and present results for protonated acetylene (C/sub 2/H/sub 3//sup +/) and the methane cation (CH/sub 4//sup +/) as examples. We demonstrate the techniques by which these methods can be generalized to determine directly vibrational motions in polyatomic molecules. 24 refs., 4 figs

Transmission of fast molecular ions through thin foils

New results on the transmission of fast molecular ions through thin foils are presented and a mechanism for the transmission process is proposed. The main feature of the postulated mechanism is that a finite fraction of the incident molecular beam does not undergo a strong Coulomb explosion while traversing the foil. Because the emerging fragments are at large internuclear separations, there is an enhanced probability for the formation of bound, long-range, excited electronic states following electron capture at the rear surface of the target

Effects seen in the interactions of fast molecular-ion beams with matter. [Angular distributions, dissociation, polorization, energy losses, transmitted fractions]

Experimental results are presented from high resolution studies of the energy- and angle-distributions for the break-up products that arise from the dissociation of a variety of fast molecular ions in thin carbon foils and in gases. The results for foil targets are compared with calculations based on a model for the polarization ''wakes'' induced in foils by the passage of fast charged projectiles. An example is given of the application of this type of dissociation measurement to the determination of a molecular structure--that of H/sub 3//sup +/. Also measurements on the transmission of fast molecular ions through carbon foils are described and results presented on the transmission probabilities, energy losses and angular distributions of the transmitted ions