COMPLEX TECHNOLOGICAL AND BIOLOGICAL RESEARCH OF SOLUTIONS FOR PERITONEAL DIALYSIS

Objective: The purpose of our work was to conduct technological, analytical, and biological investigations and stability studies of peritoneal dialysis (PD) solutions containing glucose and sodium lactate in single-chamber containers.Methods: Different formulations of PD solutions were prepared and sterilized at a temperature of 121 °C during 15 m. UV-spectrophotometric determination was performed using purified water as a blank. The spectra of the solutions were run in the range of 220 to 400 nm for the identification of an absorption maximum (λmax) and measuring the absorbance at 228-230 nm and λmaxbefore and after heat sterilization. λmax of the most PD solutions after sterilization was found in the range of 273 to 281 nm. The potentiometric determination was done for pH measuring PD solutions before and after sterilization. Alternative analytical procedure of direct argent metric method was employed for fast measuring content of chloride ions. Viability of Vero cells was evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test, neutral red (NR) uptake assay, and sulforhodamine B (SRB) test.Results: The results showed that the absorbance of the most laboratory batches of PD solutions augments significantly with increasing an autoclave heating time to the sterilization temperature and time of its cooling after sterilization. The longer these parameters, the higher is the absorbance at 228-230 and 273-281 nm indicating 3,4-dideoxyglucoson-3-en (3,4-DGE) and 5-hydroxymethylfurfural (5-HMF) contents, respectively. Glucose degradation is practically absent at short terms of heating and cooling an autoclave while sterilized samples are preserved sterile. Stability studies showed a significant decrease in the absorbance at 228-230 nm during storage with the achievement of a nadir and the following weak increase; an elevation or decrease in the absorption maximum; a substantial decline in the pH of the solution after sterilization and an insignificant pH decrease during storage. The viability of kidney cells was the highest in the SRB test and the lowest one was in the MTT test.Conclusion: The influence of sterilization regimes on the quality of conventional PD solutions and their stability during storage were studied. The highest cytotoxicity was detected in the MTT test, and the lowest one was done in the SRB test, indicating the largest vulnerability of mitochondria under the influence of PD solutions compared to the membranes permeability, functioning of kidney cell lysosomes and the ability of cells to synthesize proteins. Our studies could be useful in the context of planning development of PD solutions with the purpose of authorization and domestic manufacture of these solutions in low-and-middle-income countries

Analysis procedure of the positronium lifetime spectra for the J-PET detector

Positron Annihilation Lifetime Spectroscopy (PALS) has shown to be a powerful tool to study the nanostructures of porous materials. Positron Emissions Tomography (PET) are devices allowing imaging of metabolic processes e.g. in human bodies. A newly developed device, the J-PET (Jagiellonian PET), will allow PALS in addition to imaging, thus combining both analyses providing new methods for physics and medicine. In this contribution we present a computer program that is compatible with the J-PET software. We compare its performance with the standard program LT 9.0 by using PALS data from hexane measurements at different temperatures. Our program is based on an iterative procedure, and our fits prove that it performs as good as LT 9.0.Comment: 4 figures, 8 page

Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package

Novel Positron Emission Tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta

Overview of the software architecture and data flow for the J-PET tomography device

Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article, we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET Collaboration. We discuss the data acquisition system, reconstruction framework and image reconstruction software. Also, the concept of computing outside hospitals in the remote centers such as Świerk Computing Centre in Poland is presented

Sampling FEE and trigger-less DAQ for the J-PET scanner

In this paper, we present a complete Data Acquisition System (DAQ) together with the readout mechanisms for the J-PET tomography scanner. In general, detector readout chain is constructed out of Front-End Electronics (FEE) measurement devices such as Time-to-Digital or Analog-to-Digital Converters (TDCs or ADCs), data collectors and storage. We have developed a system capable for maintaining continuous readout of digitized data without preliminary selection. Such operation mode results in up to 8 Gbps data stream, therefore, it is required to introduce a dedicated module for on-line event building and feature extraction. The Central Controller Module, equipped with Xilinx Zynq SoC and 16 optical transceivers, serves as such true real time computing facility. Our solution for the continuous data recording (trigger-less) is a novel approach in such detector systems and assures that most of the information is preserved on the storage for further, high-level processing. Signal discrimination applies a unique method of using LVDS buffers located in the FPGA fabric

A method to produce linearly polarized positrons and positronium atoms with the J-PET detector

A method for creating linearly polarized positrons and ortho-positronium (o-Ps) atoms with the J-PET detector is presented. The unique geometry and properties of the J-PET tomography enable one to design a positron source such that the quantization axis for the estimation of the linear polarization of produced o-Ps can be determined on the event by event basis in a direction of the positron motion. We intend to use ²²Na or other β⁺ decay isotopes as a source of polarized positrons. Due to the parity violation in the beta decay, the emitted positrons are longitudinally polarized. The choice of the quantization axis is based on the known position of the positron emitter and the reconstructed position of the positronium annihilation. We show that the J-PET tomography is equipped with all needed components

Introduction of total variation regularization into filtered backprojection algorithm

In this paper we extend the state-of-the-art filtered backprojection (FBP) method with application of the concept of Total Variation regularization. We compare the performance of the new algorithm with the most common form of regularizing in the FBP image reconstruction via apodizing functions. The methods are validated in terms of cross-correlation coefficient between reconstructed and real image of radioactive tracer distribution using standard Derenzo-type phantom. We demonstrate that the proposed approach results in higher cross-correlation values with respect to the standard FBP method

Time calibration of the J-PET detector

The Jagiellonian Positron Emission Tomograph (J-PET) project carried out in the Institute of Physics of the Jagiellonian University is focused on construction and tests of the first prototype of PET scanner for medical diagnostic which allows for the simultaneous 3D imaging of the whole human body using organic scintillators. The J-PET prototype consists of 192 scintillator strips forming three cylindrical layers which are optimized for the detection of photons from the electron-positron annihilation with high time- and high angular-resolutions. In this article we present time calibration and synchronization of the whole J-PET detection system by irradiating each single detection module with a 22Na source and a small detector providing common reference time for synchronization of all the modules

Preliminary studies of J-PET detector spatial resolution

The J-PET detector, based on long plastic scintillator strips, was recently constructed at the Jagiellonian University. It consists of 192 modules axially arranged into three layers, read out from both sides by digital constant-threshold front-end electronics. This work presents preliminary results of measurements of the spatial resolution of the J-PET tomograph performed with ²²Na source placed at selected position inside the detector chamber