Wyniki wyszukiwania - BazTech

1

Podstawy teoretyczne i metody obliczeniowe dozymetrii wewnętrznej

Piwowarska-Bilska Hanna, Celler Anna, Birkenfeld Bożena

Inżynier i Fizyk Medyczny

|

2021

|

Vol. 10, nr 2

121--125

PL

W pracy przedstawiono podstawy teoretyczne, założenia fizyczne i najistotniejsze formuły matematyczne dozymetrii wewnętrznej. Zawarto opis najważniejszych metod szacowania dawek pochłoniętych przez guzy oraz organy pacjentów, którym podano radiofarmaceutyk w celu diagnostyki lub terapii w zakresie medycyny nuklearnej. Przedstawiono najważniejsze trendy rozwojowe i kliniczne uwarunkowania współczesnych technik pomiarowych dozymetrii wewnętrznej. Artykuł wypełnia poważną lukę w zakresie polskojęzycznych opracowań z dziedziny dozymetrii wewnętrznej.

EN

The work presents the theoretical background, physical assumptions and the most important mathematical formulas of internal dosimetry. It describes the most important methods for estimating the doses absorbed by tumors and the organs of patients who have been administered with radiopharmaceuticals for nuclear medicine diagnosis or therapy. The work presents the most important development trends and clinical conditioning of modern measurement techniques of internal dosimetry. The article fills a serious gap in the field of developments on internal dosimetry in Polish language.

2

Radiological and health hazards resulting from radioactivity and elemental composition of some soil samples

Al-Khawlany Abdu Hamoud, Khan A. R., Pathan J. M.

Polish Journal of Medical Physics and Engineering

|

2020

|

Vol. 26, Iss. 2

97--110

EN

Inspection of the radioactivity level in the soil is very important for human health and environmental protection. This study aims at evaluating the radiological hazards and pollution risks related to natural radionuclides and elements in the selected soil samples. Ten samples of soil were collected from different sites of Aurangabad-India and the level of radioactivity was measured using gamma-ray spectrometry with NaI (Tl) detector. Furthermore, the Physico-chemical properties such as pH, organic matter, electrical conductivity, moisture, soil texture, etc., and elemental composition of soils have been decided on using various standard techniques. The mean concentrations of 226Ra, 232Th, and 40K were 8.178, 17.408, and 96.496 Bq/kg, respectively, which are lower than the global average values of 35, 30, and 400 Bq/kg, respectively (UNSCEAR, 2000). The radiological hazard indices such as radium equivalent, absorbed dose, annual effective dose, internal index, external index, gamma index, excess lifetime cancer risk, etc., were calculated to assess the radiation hazards and compared with internationally recommended values which found to be lower than the permissibility limits.

3

On the role of LET-dependent parameters in the determination of the absorbed dose by in-phantom recombination chambers

Golnik N., Maciak G.

Nukleonika

|

2018

|

Vol. 63, No. 1

9--15

EN

The paper discusses the theoretical background in terms of the use of in-phantom recombination chambers in mixed radiation fi elds, with special attention paid to the question of how the experimentally determined, linear-energy-transfer-dependent (LET) parameters can be applied with regard to the more accurate determination of the chamber response and absorbed dose in mixed radiation fi elds. Methods of taking the recombination index of radiation quality (RIQ) measurements and theoretical consideration concerning the determination of the absorbed dose are described. Classical Bragg-Gray and Spencer-Attix cavity theories were analysed and their relationship to in-phantom recombination chambers was specifi ed. Methods concerning the estimation of correction factors with regard to RIQ measurements and their importance are highlighted.

4

Metodyka obliczania dawki pochłoniętej przez pacjenta podczas zabiegów z zakresu neuroradiologii zabiegowej na podstawie kermy

Modlińska S.

Inżynier i Fizyk Medyczny

|

2016

|

Vol. 5, nr 4

199--201

PL

Wymogi prawa narzucają na personel obliczanie dawki pochłoniętej (w grejach) i odniesienie jej wartości do limitów określonych w Rozporządzeniu Ministra Zdrowia z dnia 18 lutego 2011 r. w sprawie warunków bezpiecznego stosowania promieniowania jonizującego dla wszystkich rodzajów ekspozycji medycznej. Celem pracy jest przybliżenie metodyki obliczania dawki pochłoniętej w grejach [Gy] na podstawie parametrów otrzymanych z rejestratorów dawki, na przykład kermy. Zastosowanie współczynnika korekcji, współczynnika BSF oraz wykorzystanie arkuszy kalkulacyjnych umożliwia szybką i prostą realizację zadań postawionych przez Rozporządzenie.

EN

Legal requirements impose on staff necessity of calculation of the absorbed dose (expressed in grays) and the reference of the value to the limits set out in the Regulation of the Minister of Health on 18 February 2011 on the conditions for the safe use of ionizing radiation for all types of medical exposure. The aim of this work is to present the methodology of calculation of the absorbed dose in grays [Gy] on the basis of parameters obtained from the dosage recorders, for example kerma. The usage of correction factor, BSF factor and spread sheets enables quick and easy implementation of tasks set by the Regulation.

5

Promieniowanie gamma na wybranych zwałowiskach kopalnianych Górnego Śląska

Wróbel Ł., Dołhańczuk-Śródka A., Kłos A., Wacławek M.

Proceedings of ECOpole

|

2012

|

Vol. 6, No. 2

799--803

PL

Przedstawiono wyniki badań promieniowania gamma przeprowadzonych na 5 zwałowiskach kopalnianych znajdujących się na terenie Górnego Śląska. Wyniki te wskazują, że nie występuje na nich niebezpieczny poziom promieniowania. Wartości pochłoniętej dawki promieniowania także mieściły się w pobliżu wartości średniej (95 nGy/h), przy czym w odniesieniu do średniej światowej, wynoszącej 57 nGy/h, wartości dawki promieniowania znacząco ją przekraczały. Biorąc pod uwagę normy radiologiczne, stwierdzono, że kruszywo składowane na zwałowiskach nie stanowi zagrożenia dla środowiska i pod tym względem może być wykorzystane jako materiał budowlany. Dokonano także porównania pomiędzy zmierzoną in situ a obliczoną dawką promieniowania gamma.

EN

The results of investigations carried out on gamma rays at 5 mine dumps located in Upper Silesia. These results indicate that there is no one dangerous levels of radiation. The values of the absorbed radiation dose ranged around the mean value (95 nGy/h), and in relation to a global average of 57 nGy/h, the dose of radiation significantly exceeded it. Taking into account the radiological standard, it was found that the aggregates stored in the dumps is not a threat to the environment and as such can be used as a building material. There have also been comparisons between measured in situ, and the calculated dose of gamma radiation.

6

Electron beam decomposition of pollutant model compounds in aqueous systems

Ting T. -M., Dahlan K. Z. M.

Nukleonika

|

2011

|

Vol. 56, No. 4

349-355

EN

In this study, factors that limit the utilization of electron beam irradiation for decomposition of pollutants were investigated. Potassium hydrogen phthalate (KHP) was used as the model pollutant compound. The accumulated chemical oxygen demand (COD) removal below 2.4 kGy (applied for concentration at 85, 170, 255, 425 and 850 mg/l) was less than 10 per cent, whereas the accumulated COD removal at 215 kGy (applied for concentration at 85, 170, 255, 425 and 850 mg/l) was 198 per cent. At a lower concentration of KHP, 85 mg/l, the accumulated COD removal (for dose ranging from 0.5 to 215 kGy) was 236per cent. As the concentration of KHP increases to 850 mg/l, almost no COD removal was recorded (for dose ranging from 0.5 to 215 kGy). The results show that the removal efficiency and effectiveness of pollutants were influenced by the solute concentration and irradiation dose. When the concentration of KHP increases to a certain level, water radical species were not sufficient to form KHP radicals and, therefore, reduce the decomposition of KHP molecules. Removal of phthalate as measured by COD was restricted at a very high concentration, 850 mg/l. This indicates that the by-products have scavenged the radicals rapidly. This also suggests that, the limitation of radiolytic products of water to decompose KHP at higher concentration. A large quantity of KHP molecules would also stabilize the KHP radicals and resulting in lower removal of KHP. Similar removal trend was also observed for the actual industrial wastewater.

7

Influence of boundary effects on electron beam dose distribution formation in multilayer targets

Kałuska I., Lazurik V. T., Lazurik V. M., Popov G. F., Rogov Y. V., Zimek Z.

Nukleonika

|

2010

|

Vol. 55, No. 3

363-368

EN

Computational dosimetry play a significant role in an industrial radiation processing at dose measurements in the product irradiated with electron beams (EB), X-ray and gamma ray from radionuclide sources. Accurate and validated programs for absorbed dose calculations are required for computational dosimetry. The program ModeStEB (modelling of EB processing in a three-dimensional (3D) multilayer flat targets) was designed specially for simulation and optimization of industrial radiation processing, calculation of the 3D absorbed dose distribution within multilayer packages. The package is irradiated with scanned EB on an industrial radiation facility that is based on the pulsed or continuous type of electron accelerators in the electron energy range from 0.1 to 25 MeV. Simulation of EB dose distributions in the multilayer targets was accomplished using the Monte Carlo (MC) method. Experimental verification of MC simulation prediction for EB dose distribution formation in a stack of plates interleaved with polyvinylchloride (PVC) dosimetric films (DF), within a packing box, and irradiated with a scanned 10 MeV EB on a moving conveyer is discussed.

8

Electron beam flue gas treatment process for purification of exhaust gases with high SO2 concentrations

Chmielewski A. G., Licki J.

Nukleonika

|

2008

|

Vol. 53, suppl. 2

61--66

EN

Exhaust gases with high SO2 concentrations are emitted from combustion of high sulphur fossil fuels and from different industrial processes (e.g. copper smelter and sintering plants). The application of the electron beam process for SO2 and NOx removal from such flue gases was investigated. A parametric study was carried out to determine the SO2 and NOx removal efficiency as a function of temperature and humidity of irradiated gases, absorbed dose and ammonia stoichiometry. The efficiency 90–95% of SO2 removal was obtained in the optimal treatment conditions with an inlet SO2 concentration of up to 15% vol. The synergistic effect of high SO2 content on NOx removal was indicated. The collected by-product was a mixture of ammonium sulphate and nitrate. The content of heavy metals in the by- -products was many times lower than the values accepted for commercial fertilizers.

9

Investigation of high-dose irradiation effects on polystyrene calorimeter response

Ziaie F., Noori A.

Nukleonika

|

2006

|

Vol. 51, nr 3

175-178

EN

In this work attempts have been made to investigate the variation of polystyrene calorimeter response after frequent irradiations with an electron beam. Polystyrene calorimeters are routinely used in every radiation processing center as a traceable to NPL primary standard dosimeter. Thus, self designed high impact polystyrene as the calorimeter core was irradiated several times up to many thousands of kGy doses. After each irradiation, the specific heat capacity of the polystyrene as the main changeable parameter was measured using the differential scanning calorimeter system (DSC) in the practical temperature range of polystyrene calorimeter. Therefore, correction factors to calculate the precise absorbed dose were obtained. At the final stage, several these calorimeters were irradiated simultaneously along with two Risoe standard calorimeters and another correction factor for each tested calorimeter was calculated.

10

Dense Plasma Focus as a powerful source of monochromatic X-ray radiation

Dubrovsky A., Gribkov V., Ivanov Y., Karpiński L., Orlova M.

Nukleonika

|

2006

|

Vol. 51, nr 1

21-28

EN

A review of some experimental results obtained using the dense plasma focus (DPF) device PF-1000 is presented. The copper Ka1,2 radiation line generated by DPF in the case of device anode made of copper was the main object of this study. The predominance of this characteristic radiation over other kinds of radiation in the DPF X-ray spectrum is shown. A brief description of a new DPF 6.0 device as well as a radioenzymology experiment carried out within this device is presented.

11

Manufacturing of a graphite calorimeter at Yazd Radiation Processing Center

Ziaie F.

Nukleonika

|

2004

|

Vol. 49, nr 4

159-162

EN

In this work, a few quasi-adiabatic graphite calorimeters of different dimensions are described. These calorimeters have been manufactured by ourselves and studied for accurate absorbed dose measurements in 10 MeV electron beam. In order to prove the accuracy and reliability of dose measurements with the use of the self designed graphite calorimeters (SDC), an inter comparison study was performed on these calorimeters and RisŘ's graphite calorimeters (SC, standard calorimeter) at different doses by using a Rhodotron accelerator. The comparison shows conclusively SDC of the optimal size, the results agreeing with those obtained with the SC within 1%.