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1

High resolution 2D plastic scintillator detectors for radiotherapy departments

Woźniak Grzegorz Z., Kozłowska Beata

Polish Journal of Medical Physics and Engineering

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2023

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Vol. 29, Iss. 2

92--103

EN

Plastic scintillation detectors (PSD) have been developed for over four decades and are widely used in a variety of fields, but one can find relatively few reports of their clinical use compared to other dosimetric solutions. The inexpensive detector setup made of a Saint-Gobain BC-400 plastic scintillator and commercially available on the market CMOS-based DSLR Pentax camera was investigated. Build PSD detectors were irradiated with 6, 10 and 15 MV flattening filtered (FF) and 6 and 10 MV flattening filter free (FFF) photon beams using a clinical linear accelerator. Data were processed using Matlab software to remove background and artefacts. A comparison of the spatial resolution parameters to the Gafchromic EBT3 films was performed. Average dose difference between TPS and PSD was 1.1%. The measured spatial resolution was 0.29 mm, and it differed from the film by 1.1%. MTF50 for PSD was 0.57 mm higher than the Gafchromic film. Signal to dose fit function with an R-square equal to 0.999 was established. The standard deviation of mean pixels value for a series of measurements was below 0.1%, for variable dose rate dependence was below 0.6% and for different energies 1.1%. It was demonstrated that such a setup allows a satisfactory signal-to-dose dependence and provides high spatial resolution at an affordable price compared to a 2D ion chamber or a diode detector array. Moreover, PSDs are reusable and provide a simple readout compared to Gafchromic films commonly used in radiotherapy departments. Variable parameters of the camera allow to select signal values at the optimal level. The system presented excellent signal stability, high image resolution and a simple signal-to-dose relationship which encourages further work to investigate PSDs for use in radiation therapy departments.

2

Review of X-ray detection systems

Urbański Paweł, Grzebyk Tomasz

Opto-Electronics Review

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2023

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Vol. 31, No. 3

art. no. e146554

EN

The article presents an overview and a classification of X-ray detection methods. The main motivation for its preparation was the need to select a suitable and useful method for detecting signals from a currently developed miniature micro-electro-mechanical system (MEMS) X-ray source. The described methods were divided into passive and active ones, among which can be distinguished: chemical, luminescent, thermo-luminescent, gas ionization, semiconductor, and calorimetric methods. The advantages and drawbacks of each method were underlined, as well as their usefulness for the characterisation of the miniature MEMS X-ray source.

3

Complex dose rate calculations in luminescence dating of lacustrine and palustrine sediments from Niederweningen, Northern Switzerland

Preusser Frank, Degering Detlev, Fülling Alexander, Miocic Johannes

Geochronometria

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2023

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Vol. 50, no. 1

28--49

EN

This study focusses on dose rate determination in complex settings in two drill cores from the site of Niederweningen, northern Switzerland. A crosscheck with a certified standard material and neutron activation analyses (NAA) reveals an overall good performance of high-resolution gamma spectrometry (HR-GS) when determining dose rate-relevant elements. A second focus is on average water content during burial, by comparing measured sediment moisture with water uptake capability. Furthermore, layer models are used to investigate the impact of inhomogeneous stratification on dose rate. Finally, different scenarios to correct for radioactive disequilibrium in the uranium decay chain are investigated. While most of the applied corrections appear to have only a minor to moderate effect on age calculation, the results for one core are contradictory. Possibly, some of the applied correction scenarios are not reflecting the complex natural setting sufficiently, in particular average sediment moisture during burial and the timing of radioactive disequilibrium might be incorrectly estimated. While deposition in one core can be quite securely attributed to the period 100–70 ka, assigning the sediment sequence in the other core to the time between ca. 130 ka and 90 ka remains to some extent insecure.

4

New trends in clinical and retrospective dosimetry

Jung Aleksandra, Matusiak Katarzyna

Bio-Algorithms and Med-Systems

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2023

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Vol. 19, no. 1

69--73

EN

Selecting the proper dosimeter and methodology is crucial for accurate dose measurement, especially since the requirements are different for clinical and retrospective dosimetry. Regardless of the field-radiotherapy, X-ray diagnostic radiology or nuclear medicineefforts are continuously being made to improve radiation measurement accuracy through the development of new dosimeters, accurate calibration of instrumentation, training of staff, proper quality control and enhancement of radiation safety procedures. For instance, for retrospective dose estimation during radiation accidents, the selection of the appropriate material and knowledge of the intrinsic background signal of the selected material are crucial. In both clinical and retrospective dosimetry it is important to have adequate protocols as well as expertise in possible uncertainties, discussed here based on the authors own research.

5

Przyrządy dozymetryczne produkowane dla ludności po katastrofie w Czarnobylu

Karolewski Łukasz

Postępy Techniki Jądrowej

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2022

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z. 1

30--40

PL

Do czasów katastrofy w Czarnobylu praktycznie nie istniała produkcja sprzętu dozymetrycznego na potrzeby obywateli – pozostawał on wyłącznie w gestii wojska i instytucji naukowych, zwłaszcza w bloku państw komunistycznych. Dopiero po tej katastrofie nastąpił dynamiczny rozwój produkcji dozymetrów dla ludności, przede wszystkim w ZSRR i państwach powstałych po jego rozpadzie. Mierniki te można podzielić na 3 grupy: indykatory promieniowania, dozymetry i radiometry-dozymetry. Indykatory jedynie sygnalizują, czy bieżąca moc dawki promieniowania gamma jest bezpieczna w kontekście długotrwałego narażenia całego ciała oraz czy przekroczenie tego poziomu jest nieznaczne, czy też silne. Dozymetry zaś podają konkretną wartość mocy dawki promieniowania gamma. Dozymetry-radiometry są zaś przyrządami uniwersalnymi: oprócz mocy dawki promieniowania gamma mierzą też aktywność emiterów beta, zarówno na powierzchniach, jak i w produktach żywnościowych. Wspominane przyrządy wykazują bardzo duże różnice, jakości wykonania oraz parametrów użytkowych. Niektóre (głównie indykatory i proste dozymetry) charakteryzują się wręcz absurdalnymi rozwiązaniami technicznymi, inne zaś (szczególnie radiometry-dozymetry) są nadal bardzo użyteczne dla potrzeb amatorskich, oczywiście z zastrzeżeniem traktowania wyników, jako orientacyjnych.

EN

Till Chernobyl disaster there was no production of dosimetry equipment for popular use – those devices were only for scientfic and military purposes, especially in Communist Bloc. After that disaster began extensive development of production of dosimeters for population, mostly in USSR and countries left after dissolution of that Union. Those meters can be divided into three groups: radiation indicators, dosimeters and radiometers-dosimeters. Indicators only show, if current gamma ray dose rate is safe regarding to long-term irradiation of whole body and if exceeding of safe radiation level is slight or significant. Dosimeters give exact value of current gamma ray dose rate. On the other hand, dosimeters-radiometers are universal devices: measure gamma ray dose rate and also activity of beta emitters, both on surfaces and in food products. Mentioned devices exhibit differences of quality and performance characteristics. Some of them (mostly indicators and simple dosimeters) have sometimes ridiculous technical solutions, but other (especially dosimeters-radiometers) still are very usable for amateur usage, of course when treating measurement as only indicative.

6

Dozymetria luminescencyjna: przegląd metod, detektorów i ich zastosowań

Nowina Konopka Małgorzata, Bilski Paweł, Obryk Barbara, Marczewska Barbara, Olko Paweł, Kłosowski Mariusz, Gieszczyk Wojciech

Postępy Techniki Jądrowej

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2022

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z. 3

8--16

PL

W artykule, po krótkim opisie rozwoju historycznego, przedstawiono teorię termoluminescencji (TL). Omówiono i porównano trzy metody stymulowania luminescencji termiczną (TSL), optyczną (OSL) i radiową (RPL). Przedstawiono i opisano szeroki zakres zastosowań detektorów TL w dozymetrii indywidualnej i środowiskowej z naciskiem na pomiary ultrawysokich dawek. Jako szczególnie ważne w dozymetrii klinicznej do radioterapii nowotworów oka, opracowano termoluminescencyjne detektory planarne 2D. Opisano udział zespołu z Instytutu Fizyki Jądrowej (IFJ) w kosmicznym eksperymencie MATROSHKA. Przedstawiono również nowe materiały TL i nowe metody pomiarowe.

EN

In the paper, after a brief description of historical development, the theory of thermoluminescence (TL) is presented. Three methods of thermally (TSL), optically (OSL) and radio (RPL) stimulated luminescence are discussed and compared. A wide range of applications of TL detectors in individual and environmental dosimetry with an attention put on ultra-high dose measurements is presented and described. As particularly important in clinical dosimetry for eye-tumor radiotherapy, the planar 2D detectors TL were developed. The participation of the Institute of Nuclear Physics (IFJ) group in the Cosmos MATROSHKA experiment is described. Also, the new TL materials and measurement methods are presented.

7

Aktualne kierunki rozwoju technologii radiacyjnych – podsumowanie konferencji ICARST 2022

Walo Marta, Gryczka Urszula, Rzepna Magdalena, Chmielewska-Śmietanko Dagmara

Postępy Techniki Jądrowej

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2022

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z. 3

2--7

PL

Trwająca przez ponad dwa lata pandemia COVID-19 znacząco wpłynęła na współpracę środowiska naukowego, ograniczając kontakty wyłącznie do spotkań online, pomimo realizowania nieprzerwanie przez wiele centrów naukowych prac badawczych. Konferencja Second International Conference on Applications of Radiation Science and Technology (ICARST), która odbyła się w dniach 22-26 sierpnia 2022 r. w Wiedniu, organizowana jako jedna z pierwszych po pandemii w formie hybrydowej cieszyła się ogromnym zainteresowaniem. Naukowcy z całego świata prezentowali najnowsze osiągnięcia z zakresu wykorzystania akceleratorów, źródeł promieniowania γ, radioznaczników i promieniowania rentgenowskiego w badaniach i zastosowaniach przemysłowych. W niniejszej pracy przedstawiono aktualne kierunki rozwoju technologii radiacyjnych na podstawie doniesień prezentowanych podczas konferencji ICARST.

EN

The COVID-19 pandemic, which lasted for over two years, significantly influenced the cooperation of the scientific community, limiting contacts only to online meetings, despite the fact that many research centers carry out research work continuously. The Second International Conference on Applications of Radiation Science and Technology (ICARST), which took place on August 22-26, 2022 in Vienna, was one of the first after the pandemic in a hybrid form, which attracted great interest. Scientists from around the world presented the latest achievements in the use of accelerators, γ radiation sources, radiotracers and X-rays in research and industrial applications. This paper presents the current trends in the development of radiation technologies based on reports presented at the ICARST conference.

8

Evaluation of SRS MapCHECK with StereoPHAN phantom as a new pre-treatment system verification for SBRT plans

Sadowski Bartłomiej Mieszko, Fillmann Marta, Szałkowski Dariusz, Kukołowicz Paweł

Polish Journal of Medical Physics and Engineering

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2022

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Vol. 28, Iss. 2

84--89

EN

Introduction: The aim of this study was to evaluate the new 2-Dimensional diode array SRS MapCHECK (SunNuclear, Melbourne, USA) with dedicated phantom StereoPHAN (SunNuclear, Melbourne, USA) for the pre-treatment verification of the stereotactic body radiotherapy (SBRT). Material and methods: For the system, the short and mid-long stability, dose linearity with MU, angular dependence, and field size dependence (ratio of relative output factor) were measured. The results of verification for 15 pre-treatment cancer patients (5 brains, 5 lungs, and 5 livers) performed with SRS MapCHECK and EBT3 Gafchromic films were compared. All the SBRT plans were optimized with the Eclipse (v. 15.6, Varian, Palo Alto, USA) treatment planning system (TPS) using the Acuros XB (Varian, Palo Alto, USA) dose calculation algorithm and were delivered to the Varian EDGE® (Varian, Palo Alto, USA) accelerator equipped with a high-definition multileaf collimator. The 6MV flattening-filter-free beam (FFF) was used. Results: Short and mid-long stability of SRS MapCHECK was very good (0.1%-0.2%), dose linearity with MU and dependence of the response of the detector on field size results were also acceptable (for dose linearity R2 = 1 and 6% difference between microDiamond and SRS MapCHECK response for the smallest field of 1 × 1 cm2). The angular dependence was very good except for the angles close to 90° and 270°. For pre-treatment plan verification, the gamma method was used with the criteria of 3% dose difference and 3 mm distance to agreement (3%/3 mm), and 2%/2 mm, 1%/1 mm, 3%/1 mm, and 2%/1 mm. The highest passing rate for all criteria was observed on the SRS MapCHECK system. Conclusions: It is concluded that SRS MapCHECK with StereoPHAN has sufficient potential for pre-treatment verification of the SBRT plans, so that verification of stereotactic plans can be significantly accelerated.

9

Wdrożenie półautomatycznej metody weryfikacji zgodności pola promieniowania z polem symulacji świetlnej akceleratorów liniowych

Paluszyńska Marta, Sobocka-Kurdyk Urszula, Borowska Patrycja, Szweda Hubert, Matuszewski Krzysztof, Paciorkowska Katarzyna, Wosicki Maksymilian, Pawałowski Bartosz

Inżynier i Fizyk Medyczny

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2022

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Vol. 11, nr 1

77--83

PL

Zapewnienie oraz utrzymanie najwyższych standardów leczenia radioterapeutycznego wymaga realizacji szeregu testów oceniających jakość pracy akceleratora medycznego. Jednym z podstawowych wymagań procesu kontroli jakości jest przede wszystkim dbałość o poprawność wykonywania dedykowanych procedur, które umożliwiają weryfikację parametrów pracy akceleratora. Zgodnie z rozporządzeniem Ministra Zdrowia w sprawie warunków bezpiecznego stosowania promieniowania jonizującego, a także zaleceniami międzynarodowymi, jednym z kontrolowanych parametrów jest zgodność pola promieniowania z polem symulacji świetlnej. Od lat podstawową metodą oceny tej zgodności jest pomiar na filmie radioczułym. Celem pracy było sprawdzenie, czy tradycyjna metoda może zostać z powodzeniem zastąpiona przez częściowo zautomatyzowaną procedurę opierającą się na obrazowaniu fantomu V3 Calibration Phantom (Aquilab, Lille, Francja) z wykorzystaniem kasety portalowej akceleratora medycznego (ang. Electronic Portal Imaging Device, EPID). W pracy porównano obie metody, a także zbadano czułość metody fantomowej (EPID) w warunkach błędów kontrolowanych – pole promieniowania względem pola świetlnego przesunięto o 1 mm, 2 mm i 3 mm w kierunkach x, y oraz xy, a także zrotowano o 0,5°, 1° i 2°. Na podstawie otrzymanych wyników stwierdzono, że pomiar fantomowy z wykorzystaniem kasety portalowej charakteryzuje się większą dokładnością pomiarową i czułością na niewielkiej niezgodności pól, a automatyczna analiza pozyskanych obrazów pozwala zwiększyć szybkość i precyzję procesu kontroli jakości oraz wyeliminować błędy obserwatora. Metoda zakładająca wykorzystanie kasety portalowej oraz fantomu V3 Calibration Phantom do kontroli zgodności pola promieniowania z polem symulacji świetlnej z powodzeniem może zastąpić metodę filmową i sprawić, że proces kontroli jakości medycznych akceleratorów liniowych stanie się bardziej wydajny.

EN

Ensuring and maintaining the highest standards of radiotherapeutic treatment requires the implementation of many tests to assess the right quality of the medical accelerator’s performance. One of fundamentals of the quality control process is the correct execution of dedicated procedures that enable the verification of accelerator parameters. According to the regulation of the Minister of Health on the conditions for the safe use of ionizing radiation, as well as international recommendations, one of the controlled parameters is the compliance of the radiation field with the light simulation field. For years, the basic method of assessing this compliance has been performed with a radiosensitive film. The aim of the study was to check whether the traditional method can be replaced by a semi-automated procedure based on imaging the V3 Calibration Phantom (Aquilab, Lille, France) with the use of Electronic Portal Imaging Device (EPID). The study compares both methods as well as investigates the sensitivity of the phantom method under controlled error conditions – the radiation field was shifted relative to the light field by 1 mm, 2 mm and 3 mm in the x, y and xy directions, and rotated by 0.5°, 1° and 2°. On the basis of results obtained, it was found that the phantom measurement with the use of EPID has higher measurement accuracy, it is sensitive even to slight field inconsistencies, and that the automatic analysis of the collected images makes the process faster, more precise and free from observer’s error. The method involving the use of EPID and the V3 Calibration Phantom to control the compliance of the radiation field with the field of light simulation can replace the film method and make the quality control process more efficient.

10

Optimization System to Minimize Exposure to Occupational Noise

Reis Déborah, Miranda João, Reis Jorge, Duarte Marcus

Archives of Acoustics

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2022

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Vol. 47, No. 1

15--23

EN

This research deals with the development of an optimization system to minimize employee noise exposure in the work environment. It is known from the literature that continuous exposure to high noise levels can cause heart overload, stress, fatigue, and increase accident numbers at a production line. Thus, it is necessary to develop acoustic solutions at an industrial level that could minimize failures and accident occurrences. The rules that regulate occupational noise exposures allow an assessment of the degrees of exposure and subsequent corrections of working conditions. It is observed that the exposure is necessary for further evaluation and correction. Therefore, this research proposes to simulate occupational noise exposure conditions through mathematical models implemented in C++, using the GUROBI linear optimization package and to act previously to minimize ONIHL (Occupational Noise-Induced Hearing Loss). One of this work results is based on Doses Values, TWA (Time Weighted Average) and Distances Covered, using these three factors simultaneously through the optimization, it obtains a route that minimizes exposure and avoids ONIHL. Although there is a need for balanced doses between employees, to this end, the Designation Problem was implemented. Thus, with the routes obtained by optimization, an efficient allocation task was made for the maintenance crew, resulting in minimized and balanced doses. This model was applied to a real industrial plant that will not be identified, only methodology and results obtained will be presented.

11

Evaluation of glandular dose in mammography in presence of breast cysts using Monte Carlo simulation

Deevband Mohammad Reza, Kaveh Zeinab, Ghorbani Mahdi, Khajetash Benyamin

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 1

41--50

EN

Background: Normalized glandular dose (DgN) is an important dosimetric quantity in mammography. Aim: In this study, the effect of the presence of breast cysts and their size, number and location on DgN is evaluated. Materials and methods: The effect of the presence of cysts in breast was examined using MCNPX code. This was performed by taking homogeneous breast phantoms containing spheroid breast cysts into account. The radius of the cysts, numbers of the cysts, and depth of the cysts, and their location were variable. Various electron energies were also considered. Finally, these results were compared with the results of a cyst-less breast phantom. Results: The results show that the effect of the presence of cysts in the breast depends on the size, number and location of cysts. The presence of cysts at lower depths leads to a decrease in the DgN values, compared to the breast phantom without cysts. The presence of cysts in the breast phantom has an effect of -7 to +14 percent on the DgN values under the conditions considered in this modeling. This effect is independent of the X-ray tube voltage, the breast phantom thickness, and glandular ratio, and depends only on the number and size and location of the cysts. The bigger radius and number of cysts, the greater effect on DgN value.

12

Evaluation of clinical implications in the use of dose to water versus dose to medium by using NTCP and TCP models for urinary bladder tumours

Bharati Avinav, Mandal Susama R., Srivastava Anoop K., Rastogi Madhup, Khurana Rohini, Hadi Rahat, Gandhi Ajeet K., Mishra Lalatendu, Mishra Surendra P.

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 1

19--24

EN

Purpose: To analyze the dosimetric and radiobiological differences between dose to water versus dose to medium for patients with carcinoma of the urinary bladder. Materials and Methods: 15 patients with cancer of urinary bladder were selected for the study. VMAT plans were generated for each patient. The dose distributions were calculated in the modes dose to water and to medium with the Monaco treatment planning system. A dosimetric comparative analysis has been made between the two modes of planning in this study. Subsequently, NTCP and TCP were determined for OARs and targets respectively. Results: The mean dose to 2 cc of the rectum, small bowel, left and right femoral heads respectively was higher by 0.8, 1.2, 2.7, and 2.2% for the dose to water calculation. Similarly, the mean dose to D2, D50, and D98 for PTV was higher by 0.4, 0.3, and 0.3% for dose to water calculation. Such small dose differences had little effect on the values of TCP and NTCP. Conclusion: For patients with the urinary bladder there were very small differences between results between calculations carried out in dose to medium and dose to water modes.

13

Dosimetry audit of the CyberKnife accelerator with the SHANE phantom

Szymański Marcin, Piziorska Maria, Madetko Oskar, Ślusarczyk-Kacprzyk Wioletta, Bulski Wojciech

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 3

207--212

EN

Introduction: The aim of this study was to propose a dosimetric audit of the CyberKnife system. Dosimetry audit is an important part of the quality assurance process in radiotherapy. Most of the proposed dosimetric audits are dedicated to classical medical accelerators. Currently, there is no commonly implemented scheme for conducting a dosimetric audit of the CyberKnife accelerator. Material and methods: To verify the dosimetric and geometric parameters of the entire radiotherapy process, as is required in E2E test procedure, the CIRS SHANE anthropomorphic phantom was used. A tomography with a resolution of 1.5 mm was prepared, five PTVs (Planning Target Volume) of different volumes were drawn; approximately: 88 cm3, 44 cm3, 15 cm3, 7 cm3, 1.5 cm3. Five treatment plans were made using the 6D Skull tracking method, FIXED collimators, RayTracing algorithm. Each treatment plan was verified in a slab Phantom, with a PinPoint chamber. The dose was measured by an ionization chamber type TM31010 Semiflex, placed in the center area of the target. Results: The result of the QA verification in slab phantom was up to 5,0%. The percentage difference for the measurement in the SHANE phantom was: 4.29%, -1.42%, -0.70%, 1.37%, -1.88% respectively for the targets: 88 cm3, 44 cm3, 15 cm3, 7 cm3, 1.5 cm3. Conclusions: By analyzing various approaches to small-field dosimetry audits in the literature, it can be assumed that the proposed CyberKnife dosimetric audit using the SHANE phantom is an appropriate method of verification of the radiotherapy process. Particular attention should be paid to the target volume, adjusting it to the system capabilities.

14

Kalibracja względna komór jonizacyjnych – nowy CoP (Code of Practice) IPEM

Oborska-Kumaszyńska Dominika

Inżynier i Fizyk Medyczny

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2021

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Vol. 10, nr 1

13--18

PL

W 1990 roku IPSM (obecnie IPEM) i National Physical Laboratory (NPL) opracowały raport (CoP) dotyczący określania dawki pochłoniętej w wodzie dla megawoltowej wiązki fotonowej w radioterapii (MV) [1]. Dodatek do tego raportu został opublikowany w 2014 roku i jest dedykowany dla niestandardowych warunków wiązki fotonowej, np. dla tomoterapii. IPEM CoP został zaktualizowany w 2020 roku w zakresie różnych warunków kalibracji i odpowiadającej im nomenklatury, uwzględniających współcześnie stosowane systemy terapeutyczne z wyspecyfikowanymi polami odniesienia, w tym z małymi polami, takimi jak zdefiniowane w IAEA TRS483 [2]. Zaktualizowany CoP zawiera zalecenia w zakresie geometrii napromieniania, doboru komór jonizacyjnych, współczynników korekcyjnych i wyprowadzenie współczynników kalibracyjnych dawki pochłoniętej dla wody, do wykonywania referencyjnych pomiarów dozymetrycznych na aparatach do radioterapii. Ponadto formalizm dozymetryczny został rozszerzony na systemy terapeutyczne, które nie mogą osiągnąć standardowego pola odniesienia (10 cm x 10 cm), a zalecenia dotyczące pomiaru dawki są podane bez warunków odniesienia. Zaktualizowany CoP zawiera zalecenia dotyczące kalibracji dawki dla systemów radioterapeutycznych i pomiarów dawki w takich warunkach dla uzyskania spójności w zapisie formalizmów współczynników kalibracyjnych i ich korekcji oraz indeksacji.

EN

In 1990, the IPSM (now IPEM) and the National Physical Laboratory (NPL) published the report (CoP) regarding the determination of absorbed dose to water for the MV photon beam in radiotherapy (MV) [1]. The appendix to this report was published in 2014 and was dedicated to non-standard conditions of the photon beam, e.g. for tomotherapy. IPEM CoP has been updated in 2020 with regard to different calibration conditions and the corresponding nomenclature, taking into account current therapeutic systems with specified reference fields, including small fields, such there are defined in IAEA TRS483 [2]. The updated CoP contains recommendations for beam geometry, ionization chambers, correction factors and calibration factors of the absorbed dose to water. In addition, the dosimetric formalism has been extended to treatment systems which for the standard reference field (10 cm x 10 cm) can’t be reached and the dose measurement recommendations are given without reference conditions. This CoP provides recommendations for dose calibration for radiotherapeutic systems and dose measurement under such conditions for consistency in the recording of calibration factor formalisms and their correction and indexing.

15

Luminescence characteristics of intraplate-derived olivines

Clark-Balzan Laine, May Venera R., Preusser Frank

Geochronometria

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2021

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Vol. 48, no.1

73--94

EN

Olivine has so far attracted limited attention as a potential luminescence dosimeter. In particular, there is a dearth of information concerning the luminescence properties of geochemically characterised, pure olivine samples. Six well-characterised olivine samples from four intraplate settings are investigated in this study, including emission wavelengths and intensities, growth of signal with absorbed dose, signal stability and recovery of a given dose with a single aliquot regeneration (SAR) protocol. All tested olivines share a low-temperature (90–100°C) UV/blue thermoluminescence (TL) peak, and five of six samples also produce a low-temperature red/yellow emission. Higher temperature TL peaks, which would be thermally stable over geological timescales and could be used for dating, are rarely observed at low doses (c. 46 Gy), but detectable though dim at significantly higher doses (c. 460 Gy). Photostimulated luminescence (PSL) emissions are very dim, but reliably detected emissions are stimulated by blue, yellow and infrared (IR) light. PSL yielded generally successful dose recovery results; however, all tested signals are prone to significant anomalous fading and complex thermal transfer between unbleachable and bleachable traps. These characteristics must be addressed if olivine is to be used as a natural dosimeter for luminescence dating. Given the variety of luminescence responses, it appears that olivine samples in future dating work may need to be individually characterised prior to measurement.

16

Infrared Radiofluorescence (IR-RF) of K-Feldspar: An Interlaboratory Comparison

Murari Madhav K., Kreutzer Sebastian, Frouin Marine, Friedrich Johannes, Lauer Tobias, Klasen Nicole, Schmidt Christoph, Tsukamoto Sumiko, Richter Daniel, Mercier Norbert, Fuchs Markus

Geochronometria

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2021

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Vol. 48, no.1

105--120

EN

Infrared Radiofluorescence (IR-RF) is a relatively new method for dosimetric dating of the depositional timing of sediments. This contribution presents an interlaboratory comparison of IR-RF measurements of sedimentary feldspar from eight laboratories. A comparison of the variability of instrumental background, bleaching, saturation, and initial rise behaviour of the IR-RF signal was carried out. Two endmember samples, a naturally bleached modern dune sand sample with a zero dose and a naturally saturated sample from a Triassic sandstone (~250 Ma), were used for this interlaboratory comparison. The major findings of this study are that (1) the observed IR-RF signal keeps decreasing beyond 4000 Gy, (2) the saturated sample gives an apparent palaeodose of 1265 ± 329 Gy and (3) in most cases, the natural IR-RF signal of the modern analogue sample (resulting from natural bleaching) is higher than the signal from laboratory-induced bleaching of 6 h, using a solar simulator (SLS). In other words, the laboratory sample bleaching was unable to achieve the level of natural bleaching. The results of the investigations are discussed in detail, along with possible explanations.

17

Evaluation of effective dose and entrance skin dose in digital radiology

Shamsi Khatereh, Shabestani Monfared Ali, Reza Deevband Mohammad, Mohsenzadeh Behzad, Ghorbani Mahdi, Ebrahimnejad Gorji Kourosh, Niksirat Fatemeh

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 2

119--125

EN

Background: Ionizing radiation has an indispensable role in diagnostic radiology and clinical treatments. Apparently, medical exposure in diagnostic radiology pertains to be the preeminent man-made source of radiation.

18

Determination of effective source to surface distance and cutout factor in small fields in electron beam radiotherapy: A comparison of different dosimeters

Bayatiani Mohamad Reza, Fallahi Fatemeh, Aliasgharzadeh Akbar, Ghorbani Mahdi, Khajetash Benyamin, Seif Fatemeh

Polish Journal of Medical Physics and Engineering

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2020

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Vol. 26, Iss. 4

235--242

EN

Objective: The main purpose of this study is to calculate the effective source to surface distance (SSDeff) of small and large electron fields in 10, 15, and 18 MeV energies, and to investigate the effect of SSD on the cutout factor for electron beams a linear accelerator. The accuracy of different dosimeters is also evaluated. Materials and methods: In the current study, Elekta Precise linear accelerator was used in electron beam energies of 10, 15, and 18 MeV. The measurements were performed in a PTW water phantom (model MP3-M). A Semiflex and Advanced Markus ionization chambers and a Diode E detector were used for dosimetry. SSDeff in 100, 105, 110, 115, and 120 cm SSDs for 1.5 × 1.5 cm2 to 5 × 5 cm2 (small fields) and 6 × 6 cm2 to 20 × 20 cm2 (large fields) field sizes were obtained. The cutout factor was measured for the small fields. Results: SSDeff in small fields is highly dependent on energy and field size and increases with increasing electron beam energy and field size. For large electron fields, with some exceptions for the 20 × 20 cm2 field, this quantity also increases with energy. The SSDeff was increased with increasing beam energy and field size for all three detectors. Conclusion: The SSDeff varies significantly for different field sizes or cutouts. It is recommended that SSDeff be determined for each electron beam size or cutout. Selecting an appropriate dosimetry system can have an effect in determining cutout factor.

19

Gwieździsty poli(tlenek propylenu) jako materiał czuły na promieniowanie rentgenowskie

Swinarew A. S., Łężniak M., Gabor J., Flak T., Kubik K., Okła H., Bielicka A., Kwaśniewska A., Guia A., Swinarew B.

Przetwórstwo Tworzyw

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2018

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T. 24, Nr 1 (181)

69--85

PL

Aparatura wykorzystywana w teleradioterapii oraz obrazowaniu, wraz z postępem technologicznym, staje się coraz bardziej precyzyjna, jednak niezależnie od stopnia zaawansowania aparatury pomiarowej, przed napromieniowaniem obszarów nowotworowych pacjenta dokonuje się szeregu symulacji rozkładu dawki promieniowania. Nowe generacje dozymetrów żelowych pozwalają na coraz dokładniejszą ocenę zaabsorbowanych dawek oraz przestrzennego rozkładu promieniowania, co jest bardzo ważnym etapem w radioterapii, gdyż pozwala na efektywniejsze naświetlenie obszarów nowotworowych promieniowaniem jonizującym, minimalizując jednocześnie obszar naświetlania zdrowych tkanek. Celem pracy było otrzymanie poli(tlenku propylenu) jako dozymetru żelowego, jego charakterystyka pod kątem procesów sieciowania oraz degradacji i analiza jakościowa powstałych produktów reakcji chemicznych wywołanych promieniowaniem jonizującym. Do badań wykorzystano gwiaździsty poli(tlenek propylenu) przed oraz po napromieniowaniu. Próbką referencyjną był poli(tlenek propylenu) nie poddany ekspozycji na żaden rodzaj promieniowania w tym promieniowania rentgenowskiego. W celu określenia stopnia usieciowania, degradacji polimeru wykorzystano technikę chromatografii żelowej, na podstawie której określono średnie masy cząsteczkowe. Do jakościowej analizy produktów wytworzonych w skutek napromieniowania wykorzystano technikę FTIR/ATR. Określenie grup funkcyjnych badanego polimeru pozwoliło na ocenę zmian chemicznych jakie wystąpiły poprzez napromieniowanie.

EN

Equipment used in teleradiotherapy and imaging along with technological progress becomes more and more precise, however, irrespective of the degree of advancement of the measuring apparatus, before the radiation of the tumor areas of the patient, a series of simulations of the radiation dose distribution is performed. New generations of gel dosimeters allow more accurate assessment of dose absorbed, and the spatial distribution of radiation, which is a very important stage in radiotherapy because it allows effective exposure of the tumor areas with ionizing radiation while minimizing the irradiation of healthy tissue area. The aim of the study was to obtain polypropylene oxide as a gel dosimeter and to characterize crosslinking and degradation processes, qualitative analysis of chemical reaction products generated by ionizing radiation. The study used a poly (propylene oxide) before and after irradiation. The reference sample was poly (propylene), not exposed to any type of radiation, including X-rays. To determine the degree of crosslinking, degradation of the polymer in the technique of gel permeation chromatography was used, based on which the average molecular weights were determined. FTIR / ATR technique was used for the qualitative analysis of irradiated products. Determination of the functional groups of the examined polymer allowed the assessment of the chemical changes that had occurred by irradiation.

20

Environmental dose rate determination using a passive dosimeter: Techniques and workflow for α-Al2O3:C chips

Kreutzer S., Martin L., Guérin G., Tribolo Ch., Selva P., Mercier N.

Geochronometria

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2018

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Vol. 45, no. 1

56--67

EN

In situ dosimetry (active, passive dosimeters) provides high accuracy by determining environmental dose rates directly in the field. Passive dosimeters, such as α-Al2O3:C, are of particular interest for sites with desired minimum disturbance (e.g., archaeological sites). Here, we present a comprehensive approach obtaining the environmental cosmic and γ-dose rate using α-Al2O3:C chips. Our procedure consists of (1) homemade field containers, (2) a homemade bleaching box, (3) a rapid measurement sequence and (4) software based on R to process the measurement results. Our validation steps include reproducibility, irradiation time correction, cross-talk evaluation and source calibration. We further simulate the effect of the container against the infinite matrix dose rate, resulting in attenuation of ca. 6%. Our measurement design uses a lexsyg SMART luminescence reader equipped with green LEDs. The irradiation is carried out under the closed β-source. The minimum dose that can be determined was estimated with ca. 10 μGy. However, we also show that for the equipment used, an irradiation time correction of ca. 2.6 s is needed and irradiation cross-talk should be taken into account. The suggested procedure is cross-checked with four reference sites at Clermont-Ferrand showing a good γ-dose rate for three out of the four sites. Finally, an application example, including needed analytical steps, is presented for dosimeters buried at the archaeological site of the Sierra de Atapuerca (Spain).