Folic acid supplementation: some practical aspects

Since 1956, when Harman first postulated the free radical theory of aging, numerous studies have been carried out to test the protective action of antioxidants. One of these protective compounds used in antioxidant therapy is folic acid (FA). Folate deficiency can lead to several pathologies and its protective role is very well known. Because the negative effects of the synthetic form on the metabolism of folates and the controversy about the role of folic acid in cancer, the question is whether or not folic acid is good for everyone. In this paper we summarize some aspects of the biochemistry of folic acid and we show some precautions that should be taken into consideration when supplementing with this compound

Numerical modeling of air-vented parallel plate ionization chambers for ultra-high dose rate applications

Purpose: air-vented ionization chambers have been the secondary standard for radiation dosimetry since the origins of radiation metrology. However, the feasibility of their use in ultra-high dose rate pulsed beams has been a matter of discussion, as large losses are caused by ion recombinations and no suitable theoretical model is available for their correction. The theories developed by Boag and his contemporaries since the 1950s, which have provided the standard ion recombination correction factor in clinical dosimetry, do not provide an accurate description when used under the limit conditions of ultra-high dose rates (UHDRs). Moreover, the high-ion recombination effects of ionization chambers under extreme dose-rate applications are an obstacle to the development of adequate dosimetry standardsThis work has received funding from the EMPIR programme project 18HLT04 UHDpulse co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programmeS

Charge collection efficiency, underlying recombination mechanisms, and the role of electrode distance of vented ionization chambers under ultra-high dose-per-pulse conditions

Purpose: Investigating and understanding of the underlying mechanisms affecting the charge collection efficiency (CCE) of vented ionization chambers under ultra-high dose rate pulsed electron radiation. This is an important step towards real-time dosimetry with ionization chambers in FLASH radiotherapy. Methods: Parallel-plate ionization chambers (PPIC) with three different electrode distances were build and investigated with electron beams with ultra-high dose-per-pulse (DPP) up to 5.4 Gy. The measurements were compared with simulations. The experimental determination of the CCE was done by comparison against the reference dose based on alanine dosimetry. The numerical solution of a system of partial differential equations taking into account charge creations by the radiation, their transport and reaction in an applied electric field was used for the simulations of the CCE and the underlying effects. Results: A good agreement between the experimental results and the simulated CCE could be achieved. The recombination losses found under ultra-high DPP could be attributed to a temporal and spatial charge carrier imbalance and the associated electric field distortion. With ultra-thin electrode distances down to 0.25 mm and a suitable chamber voltage, a CCE greater than 99 % could be achieved under the ultra-high DPP conditions investigated. Conclusions: Well-guarded ultra-thin PPIC are suited for real-time dosimetry under ultra-high DPP conditions. This allows dosimetry also for FLASH RT according to common codes of practice, traceable to primary standards. The numerical approach used allows the determination of appropriate correction factors beyond the DPP ranges where established theories are applicable to account for remaining recombination losses.S

Treatment with mesenchymal stem cells in an animal model of parkinson´s disease

Consejería de Economía, Innovación y Ciencia, Junta de Andalucía P10-CTS-649

Small static radiosurgery field dosimetry with small volume ionization chambers

Purpose: To evaluate the response of the four smallest active volume thimble type ionization chambers commercially available (IBA-dosimetry RAZOR Nano Chamber, Standard Imaging Exradin A16, IBA-dosimetry CC01 and PTW T31022) when measuring SRS cone collimated Flattening Filter Free (FFF) fields. Methods: We employed Monte Carlo simulation for calculating correction factors as defined in IAEA TRS-483. Monte Carlo simulation beam model and ion chamber geometry definitions were supported by an extensive set of measurements. Type A and B uncertainty components were evaluated.Results: Commissioning of Monte Carlo 6 MV and 10 MV FFF beam models yielded relative differences between measured and simulated dose distributions lower than 1.5%. Monte Carlo simulated output factors for 5 mm SRS field agree with experimental values within 1% local relative difference for all chambers. Smallest active volume ion chamber (IBA-dosimetry RAZOR Nano Chamber) exhibits smallest correction, being compatible with unity. Correction factor combined uncertainties range between 0.7% and 0.9%. Smallest uncertainties were recorded for smallest and largest active volume ion chambers, although the latter exhibited largest correction factor. Highest contribution to combined uncertainty was type B component associated with beam model initial electron spatial Full Width Half Maximum (FWHM) uncertainty. Conclusions: Among the investigated chambers, the IBA RAZOR Nano Chamber was found to be an excellent choice for narrow beam output factor measurement since it requires minimum correction (in line with IAEA TRS-483 recommendations). This is caused by its tiny size and tissue equivalence materials which produce minimum volume averaging and fluence perturbationS

Development of an ultra-thin parallel plate ionization chamber for dosimetry in FLASH radiotherapy

Conventional air ionization chambers (ICs) exhibit ion recombination correction factors that deviate substantially from unity when irradiated with dose per pulse magnitudes higher than those used in conventional radiotherapy. This fact makes these devices unsuitable for the dosimetric characterization of beams in ultra-high dose per pulse as used for FLASH radiotherapyParticipating States; Horizon 2020; European Metrology Programme for Innovation and Research, Grant/Award Number: 18HLT04UHD PulseS

Potential use of adipose tissue stem cells in the control of aging

Cell therapy with adult stem cells is a new battle front for the control of aging. Before being used for this purpose, we need to answer several basic questions about the biochemistry and physiology of these cells. This paper presents some aspects and preliminary results obtained in our laboratory using stem cells from adipose tissue.Ministerio de Ciencia e Innovación BFU 2010 2088

Microdosimetry in low energy proton beam at therapeutic-equivalent fluence rate with silicon 3D-cylindrical microdetectors

In this work we show the first microdosimetry measurements on a low energy proton beam with therapeutic-equivalent fluence rates by using the second generation of 3D-cylindrical microdetectors. The sensors belong to an improved version of a novel silicon-based 3D-microdetector design with electrodes etched inside silicon, which were manufactured at the National Microelectronics Centre (IMB-CNM, CSIC) in Spain. A new microtechnology has been employed using quasi-toroid electrodes of 25μm diameter and a depth of 20μm within the silicon bulk, resulting in a well-defined cylindrical radiation sensitive volume. These detectors were tested at the 18 MeV proton beamline of the cyclotron at the National Accelerator Centre (CNA, Spain). They were assembled into an in-house low-noise readout electronics to assess their performance at a therapeutic-equivalent fluence rate. Microdosimetry spectra of lineal energy were recorded at several proton energies starting from 18 MeV by adding 50μm thick tungsten foils gradually at the exit-window of the cyclotron external beamline, which corresponds to different depths along the Bragg curve. The experimentalyF¯values in silicon cover from (5.7 ± 0.9) to (8.5 ± 0.4) keV μm-1in the entrance to (27.4 ± 2.3) keV μm-1in the distal edge. Pulse height energy spectra were crosschecked with Monte Carlo simulations and an excellent agreement was obtained. This work demonstrates the capability of the second generation 3D-microdetectors to assess accurate microdosimetric distributions at fluence rates as high as those used in clinical centers in proton therapy

eIMRT: a web platform for the verification and optimization of radiation treatment plans

The eIMRT platform is a remote distributed computing tool that provides users with Internet access to three different services: Monte Carlo optimization of treatment plans, CRT & IMRT treatment optimization, and a database of relevant radiation treatments/clinical cases. These services are accessible through a user-friendly and platform independent web page. Its flexible and scalable design focuses on providing the final users with services rather than a collection of software pieces. All input and output data (CT, contours, treatment plans and dose distributions) are handled using the DICOM format. The design, implementation, and support of the verification and optimization algorithms are hidden to the user. This allows a unified, robust handling of the software and hardware that enables these computation-intensive services. The eIMRT platform is currently hosted by the Galician Supercomputing Center (CESGA) and may be accessible upon request (there is a demo version at http://eimrt.cesga.es:8080/ eIMRT2/demo; request access in http://eimrt.cesga.es/signup.html). This paper describes all aspects of the eIMRT algorithms in depth, its user interface, and its services. Due to the flexible design of the platform, it has numerous applications including the intercenter comparison of treatment planning, the quality assurance of radiation treatments, the design and implementation of new approaches to certain types of treatments, and the sharing of information on radiation treatment techniques. In addition, the web platform and software tools developed for treatment verification and optimization have a modular design that allows the user to extend them with new algorithms. This software is not a commercial product. It is the result of the collaborative effort of different public research institutions and is planned to be distributed as an open source project. In this way, it will be available to any user; new releases will be generated with the new implemented codes or upgradesThis work was financed by Xunta de Galicia of Spain through grant PGIDT05SIN00101CT and by the European Community through the BeInGrid projectS

Kit y método de cuantificación de la toxicidad en neuronas de la corteza cerebral para la detección de enfermedades neurodegenerativas

La presente invención escribe un método electrofisiológico y un kit consistente en una concentración de 10 µM de hidroperóxido de cumeno puro en líquido cefalorraquídeo para cuantificar los efectos de la toxicidad sobre las propiedades intrínsecas de las neuronas de la corteza motora a los 5 minutos de exposición a la acción tóxica y su uso en la detección de enfermedades neurodegenerativas, tal como la Esclerosis Lateral Amiotrófica. Esta invención se encuadra en las áreas analítica y científico-técnica farmacéutica, concretamente en el sector de actividad farmacéutica de evaluación de propiedades de fármacos neuroprotectores.Españ