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Research on the 'social cure' points to the many positive outcomes of having strong social identifications for minority and immigrant groups. At the same time, identification is a multi-faceted psychological phenomenon, combining three dimensions: ingroup centrality, ingroup affect, and ingroup ties. The main aim of the present study was to assess the divergent effects of these three facets of social identification on acculturation stress experienced by the members of two ethnolinguistic communities of Ukrainian immigrants in Poland. The study found that ingroup centrality was related to higher levels of acculturation stress, whereas positive ingroup affect and strong ingroup ties were related to lower acculturation stress. Additionally, the immigrant community who speak Ukrainian as their mother tongue reported stronger Ukrainian identification than those declaring Russian as their mother tongue, leading to lower levels of acculturation stress among members of this community. The present study suggests that those aspects of identification that promote exclusivity (ingroup centrality) can be maladaptive in the process of acculturation, whereas the more binding ones (ingroup ties and affect) facilitate acculturation. [ABSTRACT FROM AUTHOR]

• EURADOS WG9 characterization of several passive detector systems in Proton Therapy. • Unique study comparing luminescence detectors and alanine from three institutes. • Alanine detectors demonstrated the lowest linear energy transfer (LET) dependence. • Alanine detectors show the best dosimetric properties for implementation in auditing. • Luminescence detectors require more extensive calibrations for mail auditing. The lack of mailed dosimetry audits of proton therapy centres in Europe has encouraged researchers of EURADOS Working Group 9 (WG9) to compare response of several existing passive detector systems in therapeutic pencil beam scanning. Alanine Electron Paramagnetic Resonance dosimetry systems from 3 different institutes (ISS, Italy; UH, Belgium and IFJ PAN, Poland), natLiF:Mg, Ti (MTS-N) and natLiF:Mg, Cu, P (MCP-N) thermoluminescent dosimeters (TLDs), GD-352M radiophotoluminescent glass dosimeters (RPLGDs) and Al 2 O 3 :C optically stimulated dosimeters (OSLDs) were evaluate. Dosimeter repeatability, batch reproducibility and response in therapeutic Pencil Beam Scanning were verified for implementation as mail auditing system. Alanine detectors demonstrated the lowest linear energy transfer (LET) dependence with an agreement between measured and treatment planning system (TPS) dose below 1%. The OSLDs measured on average a 6.3% lower dose compared to TPS calculation, with no significant difference between varying modulations and ranges. Both GD-352M and MCP-N measured a lower dose than the TPS and luminescent response was dependent on the LET of the therapeutic proton beam. Thermoluminescent response of MTS-N was also found to be dependent on the LET and a higher dose than TPS was measured with the most pronounced increase of 11%. As alanine detectors are characterized by the lowest energy dependence for different parameters of therapeutic pencil beam scanning they are suitable candidates for mail auditing in proton therapy. The response of luminescence detector systems have shown promises even though more careful calibration and corrections are needed for its implementation as part of a mailed dosimetry audit system. [ABSTRACT FROM AUTHOR]

Purpose To measure the environmental doses from stray neutrons in the vicinity of a solid slab phantom as a function of beam energy, field size and modulation width, using the proton pencil beam scanning (PBS) technique. Method Measurements were carried out using two extended range WENDI-II rem-counters and three tissue equivalent proportional counters. Detectors were suitably placed at different distances around the RW3 slab phantom. Beam irradiation parameters were varied to cover the clinical ranges of proton beam energies (100–220 MeV), field sizes ((2 × 2)–(20 × 20) cm 2 ) and modulation widths (0–15 cm). Results For pristine proton peak irradiations, large variations of neutron H ∗ (10)/ D were observed with changes in beam energy and field size, while these were less dependent on modulation widths. H ∗ (10)/ D for pristine proton pencil beams varied between 0.04 μSv Gy −1 at beam energy 100 MeV and a (2 × 2) cm 2 field at 2.25 m distance and 90° angle with respect to the beam axis, and 72.3 μSv Gy −1 at beam energy 200 MeV and a (20 × 20) cm 2 field at 1 m distance along the beam axis. Conclusions The obtained results will be useful in benchmarking Monte Carlo calculations of proton radiotherapy in PBS mode and in estimating the exposure to stray radiation of the patient. Such estimates may be facilitated by the obtained best-fitted simple analytical formulae relating the stray neutron doses at points of interest with beam irradiation parameters. [ABSTRACT FROM AUTHOR]

Stereotactic Synchrotron Radiotherapy (SSRT) and Microbeam Radiation Therapy (MRT) are both novel approaches to treat brain tumor and potentially other tumors using synchrotron radiation. Although the techniques differ by their principles, SSRT and MRT share certain common aspects with the possibility of combining their advantages in the future. For MRT, the technique uses highly collimated, quasi-parallel arrays of X-ray microbeams between 50 and 600 keV. Important features of highly brilliant Synchrotron sources are a very small beam divergence and an extremely high dose rate. The minimal beam divergence allows the insertion of so called Multi Slit Collimators (MSC) to produce spatially fractionated beams of typically ∼25–75 micron-wide microplanar beams separated by wider (100–400 microns center-to-center(ctc)) spaces with a very sharp penumbra. Peak entrance doses of several hundreds of Gy are extremely well tolerated by normal tissues and at the same time provide a higher therapeutic index for various tumor models in rodents. The hypothesis of a selective radio-vulnerability of the tumor vasculature versus normal blood vessels by MRT was recently more solidified. SSRT (Synchrotron Stereotactic Radiotherapy) is based on a local drug uptake of high-Z elements in tumors followed by stereotactic irradiation with 80 keV photons to enhance the dose deposition only within the tumor. With SSRT already in its clinical trial stage at the ESRF, most medical physics problems are already solved and the implemented solutions are briefly described, while the medical physics aspects in MRT will be discussed in more detail in this paper. [ABSTRACT FROM AUTHOR]

Irradiation, delivered by a synchrotron facility, using a set of highly collimated, narrow and parallel photon beams spaced by 1 mm or less, has been termed Microbeam Radiation Therapy (MRT). The tolerance of healthy tissue after MRT was found to be better than after standard broad X-ray beams, together with a more pronounced response of malignant tissue. The microbeam spacing and transverse peak-to-valley dose ratio (PVDR) are considered to be relevant biological MRT parameters. We investigated the MRT concept for proton microbeams, where we expected different depth-dose profiles and PVDR dependences, resulting in skin sparing and homogeneous dose distributions at larger beam depths, due to differences between interactions of proton and photon beams in tissue. Using the FLUKA Monte Carlo code we simulated PVDR distributions for differently spaced 0.1 mm (sigma) pencil-beams of entrance energies 60, 80, 100 and 120 MeV irradiating a cylindrical water phantom with and without a bone layer, representing human head. We calculated PVDR distributions and evaluated uniformity of target irradiation at distal beam ranges of 60–120 MeV microbeams. We also calculated PVDR distributions for a 60 MeV spread-out Bragg peak microbeam configuration. Application of optimised proton MRT in terms of spot size, pencil-beam distribution, entrance beam energy, multiport irradiation, combined with relevant radiobiological investigations, could pave the way for hypofractionation scenarios where tissue sparing at the entrance, better malignant tissue response and better dose conformity of target volume irradiation could be achieved, compared with present proton beam radiotherapy configurations. [ABSTRACT FROM AUTHOR]

Abstract: Several models of Radial Dose Distribution predict that in the track core of the heavy ion, at the radial distances closer than 1 nm the local dose can exceed 100 kGy, but this prediction has never been experimentally verified. Within this work MCP-N (LiF:Mg,Cu,P) thermoluminescence (TL) detectors, which show high temperature TL glow peak structure between 350 °C and 500 °C after exposure to doses of gamma-rays as high as 1 MGy, were irradiated with Am-241 α-particles with fluences 107–1011 particles/cm2. For fluences 9 × 109 cm−2 in MCP-N TL glow curves high temperature peaks were observed which confirmed that a fraction of energy of α-particles was transferred with the local doses exceeding 50 kGy. Calculation of dose (fluence) dependent microdosimetric distributions confirmed that at these fluences and target diameters of 80 nm high dose regions do not result from overlapping of tracks. It was estimated that approximately 20% of entire energy of 5.5 MeV α-particle penetrating LiF was deposited with local doses exceeding 50 kGy. [Copyright &y& Elsevier]

Abstract: Radiotherapy with a proton beam of initial energy 55–80MeV is presently the clinically recommended therapy for some cases of intraocular melanoma such as large melanomas or tumours adjacent to critical organs. Evaluation and optimization of radiation doses outside the treatment volume may contribute to reducing undesirable side-effects and decreasing the risk of occurrence of secondary cancers, particularly for paediatric patients. In this work the undesired doses to organs were assessed basing on Monte Carlo calculation of secondary radiation transport and on results of measurements of neutron and γ-ray doses at the proton therapy facility of the Institute of Nuclear Physics at Kraków. Dosimetry was performed using a He-3-based FHT 762 neutron monitor (Wendi II), a FH40G proportional counter (for γ-rays), and MTS-7 (LiF:Mg,Ti) thermoluminescence detectors (TLDs). Organ doses were calculated in the ADAM anthropomorphic phantom using the MCNPX Monte Carlo transport code and partly verified, for γ-ray doses, with TLD measurements in the RANDO Anderson anthropomorphic phantom. The effective dose due to undesired radiation, including exposure from scattered radiation during the entire process of proton radiotherapy and patient positioning using X-rays, does not exceed 1mSv. [ABSTRACT FROM AUTHOR]

Abstract: The dose response of three LiF TLDs: standard LiF:Mg,Ti (denoted MTS), high-sensitive LiF:Mg,Cu,P (MCP) and a recently developed in Kraków version of LiF:Mg,Ti with modified activator composition (MTT) and increased high-LET response was measured. The TLDs have been exposed to 60Co gamma-rays, up to dose of 10000Gy, i.e. beyond saturation dose of the main dosimetric peaks, which corresponds to ca. 1000Gy. The measured glow-curves were deconvolved into separate peaks with first order kinetic function (using self-developed GlowFit software). The dose response of the main peaks was found to be supralinear for MTS and sublinear for MCP detectors, as expected. The dose response of MTT was found to be even more supralinear than that of MTS. An interesting effect has been observed with regard to glow-curve shape of MCP detectors. Up to a dose of 1kGy it remains practically unchanged, while for higher doses a strong growth of high-temperature peaks is observed. In the same dose region a decrease of the main peak of MCP with increasing dose is observed, unlike LiF:Mg,Ti detectors. [Copyright &y& Elsevier]

An environmental radiation monitoring system using standard MTS-N (LiF:Mg, Ti) and high-sensitive thermoluminescent LiF:Mg,Cu,P (MCP-N) detectors was applied to control the radiation exposure over the area of the Institute of Nuclear Physics (INP) in Kraków. First environmental measurements using MTS-N detectors began in 1970 at five locations and were continued during the Chernobyl accident at six sites. In March 1987 high-sensitive MCP-N detectors read out in a manual TL reader were first introduced into service at the INP. Since 1992 about 60 locations over an area of the INP were selected for quarterly dose rate measurements, using an automatic TLD system based on MTS-N detectors placed in cards. In 2002 MTS-N detectors were replaced by high-sensitive MCP-N pellets.The dose rate in long-term measurements changed over the last 30 years. The average gamma dose rate over the area of INP in the years 1975–1978 was 63 nGy-1. After the Chernobyl accident the gamma dose rate increased to 880 nGyh-1. In December 1986 the dose rate at the location place decreased to 103 nGyh-1. At present, the average dose rate has returned to the pre-Chernobyl level of about 68 nGyh-1. Construction and beam tests of a new isochronous cyclotron at the INP resulted in highly enhanced environmental dose rates at several monitored INP sites. In this work results of almost 11 years of environmental indoor and outdoor measurements with thermoluminescent detectors are summarised. [Copyright &y& Elsevier]

Microbeam radiation therapy (MRT) is an irradiation modality for therapeutic purposes which uses arrays of collimated quasi parallel microbeams, each up to 100 μm wide, to deliver high radiation doses. Several studies have reported the extraordinary tolerance of normal tissues to MRT irradiation; conversely, MRT has been shown to be highly efficient on tumor growth control. The original and most widely developed application of MRT, yet in the preclinical phase, consists in using spatially fractionated X-ray beams issued from a synchrotron radiation source in the treatment of brain tumors. More recently, MRT has been tested in successful pioneering assays to reduce or interrupt seizures in preclinical models of epilepsy. The MRT concept has also been extended to proton therapy. The development of MRT towards its clinical implementation is presently driven by an EU-supported consortium of laboratories from 16 countries within the COST Action TD1205 (SYRA3). The results of the first SYRA3 workshop on “Radiation Therapy with Synchrotron Radiation: Achievements and Challenges” held in Krakow (Poland) during March 25–26 2014 are summarized in this issue with an overview presented in this paper. The papers reflect the multidisciplinary international activities of SYRA3. The topics covered in this focus issue include medical physics aspects, pre-clinical studies, clinical applications, and an industrial perspective; finally an outlook towards future prospects of compact sources and proton microbeams. [ABSTRACT FROM AUTHOR]

Abstract: In the Henryk Niewodniczański Institute of Nuclear Physics of the Polish Academy of Science in Krakow (IFJ PAN), Poland, in cooperation with the Department of Ophthalmology and Ophthalmic Oncology of the Collegium Medicum, Jagiellonian University and the Centre of Oncology of the Maria Skłodowska-Curie Memorial Institute Krakow Branch, is running the project of designing and operating a proton ocular radiotherapy facility in which the 60 MeV proton beam accelerated in the AIC-144 isochronous cyclotron of IFJ PAN is applied. The facility will be able to satisfy national needs of ocular melanoma therapy in Poland (about 100 cases per year). [ABSTRACT FROM AUTHOR]

The response of a large-area two-dimensional (2D) thermoluminescence (TL) dosimetry system with 20 × 20 cm 2 TL LiF:Mg,Cu,P foils, developed at the Institute of Nuclear Physics PAN was studied for doses of therapeutic proton beams with energies of 80 MeV, 150 MeV and 225 MeV. The one-hit detector model fitted to measured dose response yielded characteristic doses of 227 Gy, 209 Gy and 203 Gy respectively. The system was applied to investigate geometrical parameters of spots produced by proton pencil beams at the Bronowice Cyclotron Centre IFJ PAN. Mean spot sizes measured with TL foils were compared with mean spot sizes calculated for Gafchromic ® films. It was shown that the 2D TL system was capable to measure the spot size up to peak doses of 20 Gy without additional correction for dose response. For measurements of the spot size using Gafchromic ® EBT3 films an additional calibration must be applied to correct for the non-linear response for doses exceeding 1 Gy. [ABSTRACT FROM AUTHOR]

A new method of experimental verification of radial dose distribution models using solid state thermoluminescent (TL) detectors LiF:Mg,Cu,P has been recently proposed. In this work the method was applied to verify the spatial distribution of energy deposition within a single 131 Xe ion track. Detectors were irradiated at the Department of Physics of the University of Jyväskylä, Finland. The obtained results have been compared with theoretical data, calculated according to the Zhang et al., Cucinotta et al. and Geiss et al. radial dose distribution (RDD) models. At the lowest dose range the Zhang et al. RDD model exhibited the best agreement as compared to experimental data. In the intermediate dose range, up to 10 4 Gy, the best agreement was found for the RDD model of Cucinotta et al. The probability of occurrence of doses higher than 10 4 Gy within a single 131 Xe ion track was found to be lower than predicted by all the studied RDD models. This may be a result of diffusion of the charge, which is then captured by TL-related trapping sites, at the distances up to dozens of nanometers from the ionization site. [ABSTRACT FROM AUTHOR]

Abstract: The most popular types of LiF-based thermoluminescent (TL) detectors, LiF:Mg,Ti (MTS-N) and LiF:Mg,Cu,P (MCP-N), have been investigated, with respect to their dose (fluence) response and relative TL efficiency to different ion species. The detectors were irradiated using the nitrogen, iron, krypton and xenon ion beams, at energies ranging from 5.0 to 9.3 MeV/n. Supra- and sublinear response was found, for the MTS-N and MCP-N, respectively, similarly as observed for γ-rays. However, the level of nonlinearity of response of studied detectors is strongly reduced by increasing values of the ion ionization density (no supralinearity for Xe ions, for MTS-N, within calculated uncertainties). The growth of high-temperature TL peaks, with increasing ionization density, was observed for MCP-N, what was not previously reported. At the whole range of applied energies higher efficiencies were noted for MTS-N, for all ion species. A decrease of the efficiency with decrease of the ion energy was confirmed, for both types of studied detectors. At a given energy, higher efficiency was observed for lighter ions, because of the lower ionization density. Significantly higher decrease of the efficiency was measured for MCP-N. The obtained results remain in a general agreement with other theoretical and experimental data. The data collected for the highest doses (fluences) of Xe ions will be used for testing a recently proposed method of experimental verification of radial dose distribution models. [Copyright &y& Elsevier]

Abstract: Using a two-dimensional thermo luminescent (TL) system consisting of MCP-N (LiF:Mg,Cu,P) TL detectors and self-developed TLD reader with a CCD camera (TL-CCD reader) a method of distinguishing between static and dynamic radiation exposure to X-rays was developed. MCP-N TL detectors installed in the RADOS dosimetry badge were covered with non-uniform Pb and Cu filters. Quantitative identification of the static exposure cases was performed by analyzing the distribution of pixel intensity in the images obtained in the TL-CCD reader (). We demonstrate the possibility of automatically distinguishing cases of static exposure for doses as low as 5 mSv, up to mean X-ray energies of 250 keV and for exposure angles up to 60°. [Copyright &y& Elsevier]

Abstract: The behaviour of LiF:Mg,Cu,P (MCP-N) detectors at ultra-high doses up to 500kGy has been investigated. Some very significant changes of the glow-curve shape have been revealed. The most important finding is the appearance of a new peak at exposures above 50kGy, the position of which shifts toward higher temperatures with increasing dose (from 405 to 470°C at 500kGy), in contradiction to standard TL models. The E and s trapping parameters also increase with increasing dose. This new peak appears to have potential application for ultra-high-dose measurements. The TL emission spectrum also changes at such high doses with the appearance of several new bands of wavelengths up to 800nm. [Copyright &y& Elsevier]

Abstract: We studied the difference between the response of standard 7LiF:Mg,Ti (MTS) thermoluminescence detectors and the response of a new version of 7LiF:Mg,Ti (MTT) with modified activator composition and increased high-LET response. In this study we used the Co-60 radiotherapy beam at IFJ in Kraków and charged particle beams of the HIMAC accelerator in Chiba. The MTS and MTT detectors were exposed and annealed in the same conditions and the analysis was performed via the experimental method and deconvolution with a first-order kinetic function, using the GlowFit software, recently developed at IFJ. We found that although the number of peaks in both materials is the same, the shape of MTT glow curve is quite different, compared to the standard MTS. The difference lies in the proportions between particular peaks and also in their kinetic peak parameters. Temperatures of the peak maxima in MTT are shifted towards lower values. The activation energies also change, making the peaks wider and the TL glow curve more complex. This feature is visible especially in the main peak region where peaks 4 and 5 overlap. Another difference in MTT is in the high-temperature peak region, which is more pronounced and differently shaped. The signal originating from peak 3 is stronger in MTT and gives the strongest contribution to the total signal. [Copyright &y& Elsevier]

A novel method of determining two-dimensional (2-D) dose distributions was developed using in-house produced large-area thermoluminescent (TL) detectors based on LiF, read with a newly developed planar large-area TL reader equipped with a CCD camera. The detectors were developed by attaching, pressing and sintering thermoluminescent LiF:Mg,Ti or LiF:Mg,Cu,P powder on Al foil of 0.3 mm thickness. The detectors, of active area of a few square centimeters, read out using the large-area TL reader, were successfully used to map the 2-D dose distribution around an alpha source Am-241, a Ra-226 needle source and a Ru-106 ophthalmic applicator. [Copyright &y& Elsevier]

The properties of LiF:Mg,Ti (distributed as, e.g., TLD-100 or MTS-N), the most frequently used thermoluminescent detector, have been optimised for measurements of sparsely ionising radiation (gamma rays), typically encountered in radiation protection or clinical dosimetry. However, these detectors need also to be applied in conditions of mixed-field dosimetry with a high-LET component, such as those encountered in heavy ion beams or in space.At the Institute of Nuclear Physics in Kraków a new type of LiF:Mg,Ti detector (named MTT) has been recently developed through modification of its dopant composition. This composition is intended to increase the detection efficiency after a dose of high-LET radiation. The concentration of dopants in the MTT material is: CMg=50 ppm, and CTi=120 ppm, i.e. about a three times less of magnesium and about 10 times more of titanium content, compared with the standard MTS-N. The MTT TL detectors feature an increased relative efficiency to high-LET radiation, which for 5 MeV alpha-particles is about twice that of standard LiF:Mg,Ti. The response of MTT detectors has been studied in charged particle beams of the HIMAC accelerator in Chiba, Japan and in Dubna, Russia. The main foreseen application of MTT detectors are dose measurements in space. The dose after high-LET exposure can be estimated from the difference of the response of MTS and MTT detectors. In the near future MTT detectors will be applied in the “Matroshka” experiment. Within this experiment a specially constructed human phantom will be exposed in free space (outside the International Space Station) for 1 year. The phantom will incorporate a few thousand measuring points enabling radiation doses to particular organs to be determined. [Copyright &y& Elsevier]

Fluorescent nuclear track detectors based on LiF crystals were successfully applied for detection of proton induced tracks. Irradiations were performed with protons with energy ranging from 1 MeV up to about 56 MeV and for all proton energies the fluorescent tracks were observed. The tracks are not continuous, but consist of a series of bright spots. The gaps between spots tend to narrow with decreasing proton energy (increasing ionization density). For the highest of the studied energies, the spots are scattered so sparsely, that it is not possible to link spots belonging to one track. The intensity (brightness) of the fluorescent tracks increases with the increasing LET and agrees well with the trend established earlier for various heavier ions. • Tracks of single protons registered with LiF FNTDs. • Intensity of tracks increases with increasing LET. • Tracks are not continuous, but consist of a series of bright spots. • Gaps between spots tend to narrow with decreasing proton. [ABSTRACT FROM AUTHOR]

This paper compares the performance of four different Tissue-Equivalent proportional counters (TEPC) first in standard radiation fields, with gamma and neutron sources, then in the mixed and complex/intense neutron and photon stray radiation field of a scanning proton therapy facility. The paper focuses on the dead time correction and introduces a new spectra processing methodology to enable the comparison of the four TEPCs while accounting for their different gas filling and gain, lineal energy range of the spectrum and the analysis methodology. Measurements with 137 Cs and/or 60 Co gamma sources demonstrate variable low-LET threshold for each TEPC while data acquired with a 252 Cf neutron source show comparable response of the four TEPCs for high-LET particles. Meanwhile, in the scattered field of proton therapy, microdosimetric spectra measured at different positions and orientations around the patient show a majority of high-LET events at the smallest angle with respect to the beam axis while low-LET particles were mainly dominant at 90° from the beam axis. The introduced processing methodology led to good overlapping of microdosimetric spectra for the four systems. [ABSTRACT FROM AUTHOR]

Abstract: The first objective of this work was to check and select a set of four kinds of passive photon, dosimeters (two thermo-luminescence dosimeter (TLD) types, one radiophotoluminescence (RPL) dosimeter and one optically stimulated luminescence (OSL) dosimeter) together with a common measurement protocol. Dosimeters were calibrated in a reference clinical linear acccelerator beam in a water tank at a reference facility at the Laboratoire National Henri Becquerel (CEA LIST/LNE LNHB, Saclay. Radiation qualities of 6, 12 and 20 MV were used with standard calibration conditions described in IAEA TRS 398 and non-standard conditions. Profile and depth dose ion chamber measurements were also made to provide reference values. Measurements were made in a water tank into which pipes could be inserted which held dosimeters in pre-determined and reproducible positions. The water tank was built to enable investigation of doses up to 60 cm from the beam axis. A first set of experiments was carried out with the beam passing through the tank. From this first experiment, penumbra and out-of-field dose profiles including water and collimator scatter and leakage were found over three orders of magnitude. Two further sets of experiments using the same experimental arrangement with the beam outside the tank, to avoid water scatter, were designed to measure collimator scatter and leakage by closing the jaws of the collimator. Depending on the energy, typical leakage and collimator scatter represents 10–40% and 30–50% of the total out-of-field doses respectively. It was concluded that all dosimeters can be used for out-of-field photon dosimetry. All show good uniformity, good reproducibility, and can be used down to low doses expected at distances remote from the subsequent radiotherapy target volume. [Copyright &y& Elsevier]

Abstract: Following the recent ICRP recommendation to decrease the limit of occupational exposure to the eye lens from 150 mSv to 20 mSv/year, a dedicated individual eye-lens dosemeter, EYE-D™, was developed at the IFJ PAN. This dosemeter uses MCP-N (LiF:Mg,Cu,P) thermoluminescent detectors covered with a polyamide capsule and was so far optimized to achieve a flat photon energy and angular response for X-ray exposures typical in interventional radiology. To verify the applicability of this eye-lens dosemeter in external β-ray fields which arise, e.g. in nuclear medicine procedures, we measured and calculated its β-ray energy and angular response. Measurements, applying β-rays from Sr-90/Y-90 isotope, were performed at the Beta Secondary Standard type 2 (BSS 2) in CLOR. Calculations, using the PENELOPE Monte Carlo transport code which simulates coupled electron and photon transport in arbitrary materials, were performed for P-32, K-42 and Sr-90/Y-90 fields to simulate doses received by the eye lens within the human body. PENELOPE Monte Carlo transport code was also used to calculate doses received with EYE-D™ detectors. We found good agreement between the measured and calculated energy and angular responses which confirms the suitability of this dosemeter in assessing Hp(3) to estimate the eye lens. Obtained results and conclusions, however preliminary, conform with current ICRP recommendations when performing individual radiation protection dosimetry in external β-ray fields occurring in nuclear industry and nuclear medicine activities. [Copyright &y& Elsevier]

High-sensitive thermoluminescent detectors LiF:Mg,Cu,P have been investigated after exposures with γ-rays doses up to hundreds of kGy. Both emission spectra and TL glow curves have been measured up to temperature of 550 °C. TL emission spectra integrated over a temperature range of 47–470 °C were analyzed. Two emission regions, main (220–450 nm) and long wavelength (450–800 nm), were distinguished. No significant changes, with increasing dose, were observed in the main emission. The long wavelength emission was visible at the doses of 4 kGy and higher, indicating that such an amount of energy, deposited in the detector volume, makes additional recombination centers active. At the “B” peak temperature range (above 400 °C), the wavelength of emitted light was nearly identical, as for the main glow peak (∼220 °C) at lower doses. It tends to suggest that high-dose high-temperature emission of MCP-N occurs along the same recombination path as the emission below the saturation level. Gaussian deconvolution in the energy domain was also performed for the measured spectra. The results of deconvolution remain in a general agreement with previous measurements. [ABSTRACT FROM AUTHOR]

Abstract: The available experimental data on the relative thermoluminescent efficiency of the LiF:Mg,Ti dosimetric peaks for protons are contradictory. There are several reports showing that the efficiency exceeds unity by even more than 30%, however, many others show the efficiency close to unity or even lower. These contradictory data might be a result of the real variability of TLD properties or of not perfectly reproduced experimental conditions. In an attempt to resolve this issue, the efficiency of 16 batches of LiF:Mg,Ti (MTS) detectors for 60 MeV protons produced at the IFJ Kraków over the last 20 years was measured. All values of the relative TL efficiency were found to exceed unity significantly, with an average of 1.09. Dispersion between different batches was very low, all data were within 4% of the mean value. In second part of experiment the dependence of the relative efficiency of LiF:Mg,Ti and LiF:Mg,Cu,P detectors on proton energy was determined. The efficiency for LiF:Mg,Ti dosimetric peaks was found to have a maximum of 1.20 at about 20 MeV. For LiF:Mg,Cu,P the relative efficiency decreases systematically with decreasing proton energy, from 0.96 at 56 MeV, to 0.61 at 11 MeV. [Copyright &y& Elsevier]

High-temperature emission spectra of LiF:Mg,Cu,P (MCP-N) TL detectors, irradiated above the nominal saturation level, up to the hundreds of kGy, have been measured. Emission spectra integrated over the whole temperature range, as well as the spectra recorded at the temperatures corresponding to the TL peaks maxima, were analyzed. With increasing dose of γ-radiation no significant changes were observed in the short wavelength emission range (220–450 nm) of the measured spectra. For doses of 4 kGy and higher the long wavelength emission (450–800 nm) started to be visible. All recorded spectra have been expressed in a form of the sum of several Gaussian-shape bands in the energy domain, which parameters remain in a general agreement with the measurements of Mandowska et al. (2010). Spectra of the low-temperature, main, high-temperature and “B” TL peaks were investigated. In the ranges of the low-temperature and the main dosimetric peaks, that is 100–125 and 210–230 °C, respectively, the short wavelength emission disappeared with increasing dose and for the highest doses the long wavelength emission became dominant. Both the high-temperature (290–320 °C) and the “B” (370–425 °C) peaks emission spectra exhibited somewhat different behavior with increasing dose. Initially, an even growth of the whole spectrum was observed and for doses higher than 16 kGy the intensity of the spectrum decreased, but the short wavelength emission band fell significantly faster, in case of the high-temperature TL peaks. In case of the “B” peak emission spectra the long wavelength emission did not play any role in the analyzed dose range. The spectra measured at the TL peaks maxima were also fitted with several Gaussian-shape bands. Dose-intensity dependences for all Gaussian-shape bands fitted to the measured spectra are also included in this paper. [ABSTRACT FROM AUTHOR]

Abstract: Two-dimensional (2D) thermoluminescence (TL) dosimetry systems based on LiF:Mg,Cu,P, together with the newly developed, based on CaSO4:Dy, were tested under radiotherapy beams. The detectors were irradiated in a water phantom with 6 MV X-ray beams from linac and read with a dedicated TLD reader. Dose distributions of differently shaped fields and of a full stereotactic plan were measured and compared with planned distributions. Maximum distance-to-agreement (DTA) in the penumbra region was 1 mm for both LiF:Mg,Cu,P and CaSO4:Dy TL sheets, for all the measured fields. Maximum percentage dose difference (DA%) between planned and measured dose value in low dose gradient regions was up to 11% for LiF:Mg,Cu,P TL sheets and 18% for CaSO4:Dy TL sheets. Concerning the full stereotactic plan, the percentage of points with γ-index below 1 is 54.9% for the LiF:Mg,Cu,P-based foil and 96.9% for the CaSO4:Dy TL sheets. Both 2D TL detector types can be considered to be a promising tool for bi-dimensional dose measurements in radiotherapy. Non-homogeneity, presumably due to the TL sheets manufacture, still affects dosimetric distribution and the agreement between planned and measured distributions may depend on the chosen sample. [Copyright &y& Elsevier]

Abstract: Reduction of undesired exposure to scattered neutron and gamma radiation associated with proton therapy should reduce the risk of occurrence of secondary cancers, especially in paediatric patients. By replacing the patient with a RANDO® antropomorphic phantom, we determined the undesired radiation doses during the entire course of treatment at the ocular proton radiotherapy facility at IFJ PAN in Kraków and estimated the associated risk of secondary cancers. The highest exposure from the scattered radiation, per therapeutic proton absorbed dose, was found in the brain close to the target volume. Using TASTRAK PADC track detectors we estimated the fast neutron dose equivalent in the brain at 15.2 μSv/Gy, a value consistent with 17.06 μSv/Gy obtained from MCNPX 2.5.0 Monte Carlo calculations. The ambient dose equivalent, H ∗(10), determined with WENDI II and FHT 192 detectors at the position of the patient (50 cm below the isocentre), was 2.41 μSv/Gy from neutrons and 0.43 μSv/Gy from γ-rays, respectively. Based on estimated values of organ dose equivalents, we evaluate the whole-body risk of fatal secondary cancers per course of treatment at below 0.001%. [Copyright &y& Elsevier]

Abstract: Based on the newly discovered feature of LiF:Mg,Cu,P (MCP) detectors’ glow-curves at high and ultra-high doses, a new method of thermoluminescent (TL) measurement of radiation doses ranging from micrograys up to a megagray, has been recently developed at the Institute of Nuclear Physics (IFJ). The occurrence of a new, well separated TL peak has been observed in their glow-curves resulting from many specific radiation qualities, among them gamma, electron and proton beams, for doses of about 50 kGy and higher. The occurrence of the peak B follows significant growth of previously observed high temperature peaks of the glow-curve following smaller doses. This allows MCPs to be used for dosimetry of specific radiation types in the ultra-high dose range. In order to verify the response of MCP detectors to very high doses of high-LET radiation, the glow-curve behaviour of different types of these detectors, resulting from high and ultra-high thermal neutron fluences, was studied in this work. TLDs were exposed to the neutron spectrum of the TRIGA Mark II reactor at the Reactor Research Centre at the Jožef Stefan Institute in Ljubljana. The occurrence of the high dose peak B in the MCP detectors’ glow-curve resulting from high-LET neutrons was confirmed. Results of this experiment are presented in this paper. Thus the method of ultra-high dose TL measurements was proved to be useful in interpreting the glow-curves following thermal and epithermal neutron irradiation. [Copyright &y& Elsevier]

Abstract: MTS-N detectors are pellets of LiF:Mg,Ti produced at the Institute of Nuclear Physics (IFJ) in Krakow, Poland. The thermoluminescence (TL) response of these detectors to gamma radiation doses up to 10 kGy only has been studied earlier. The aim of this paper is to evaluate the TL and EPR response of MTS detectors irradiated with 60Co gamma radiation at high doses up to 1200 kGy. The results indicate that the MTS-N glow curve presents a new peak at temperature near 420 °C for doses over 700 kGy. This peak is probably associated with the second EPR signal that appears for doses over 100 kGy. The defect center related to this signal is undergoing further studies. [Copyright &y& Elsevier]

Abstract: Depth–dose curves in LiF detectors of different effective thicknesses, together with their responses, were calculated for typical nuclear medicine radiation fields with 99mTc, 18F and 90Y sources. Responses were analysed in function of the radionuclide, detector effective thickness and irradiation geometry. On the other hand the results of the nuclear medicine measurement campaign of the ORAMED project were presented focussing on the dose distribution across the hand and on the appropriate position to wear the dosimeter. According to the results, thin LiF detectors provide better responses in all cases. Its use is essential for 18F, since thick dosimeters can underestimate H p(0.07) up to a 50% because of the very inhomogeneous dose deposition on the active layer. The preliminary results of the measurement campaign showed that the index tip of the non-dominant hand is usually the most exposed position among the 22 monitored positions. It was also found that, in average, wrist dosimeters are likely to underestimate the maximum skin dose by a factor of the order of 20. This factor is reduced to around 6 for a ring dosimeter worn on the base of the index of the non-dominant hand. Thus, for typical nuclear medicine procedures, the base of the index of the non-dominant hand is recommended as the best monitoring option. [Copyright &y& Elsevier]

Abstract: The AIC-144 isochronous cyclotron at the Institute of Nuclear Physics (IFJ) in Kraków can be used for acceleration of light ions. Protons can be accelerated to maximum energy of 60 MeV in the form of a focused ion beam. In October 2009 the AIC-144 isochronous cyclotron at the IFJ was dedicated to the Kraków Centre for Hadron Radiotherapy. Then, the cyclotron was modernized and adapted for proton radiotherapy of eye cancer. The aim of our work was to validate suitability of different thermoluminescent (TL) detector types for dosimetry of a mixed radiation field at the cyclotron unit. LiF:Mg,Ti and LiF:Mg,Cu,P detectors are well known standards of TL dosimetry; however, several of their properties are significantly different. In this study four types of LiF-based TL detectors were used to measure spatial dose distribution of a mixed radiation field in the Cyclotron Hall during operation of the machine. A program named the MapFly was developed in order to visualize radiation levels in the Cyclotron Hall in 2D and 3D. [Copyright &y& Elsevier]

Abstract: Proton therapy of eye tumors requires precise positioning in the sub-millimeter range. For this reason small (2.5 mm in diameter and a thickness of 0.2 mm) tantalum markers (clips) are sutured onto the sclera around the tumor base and used for radiological verification of the position and orientation of the eye at each treatment session. In some cases during irradiation clips might be positioned between the tumor and radiation source that may lead to perturbation of the dose distribution and underdosing of some parts of a tumor. The aim of this work was to determine experimentally the dose distribution behind the tantalum clips after irradiation with the parallel proton beam. The dose measurements were performed using the two-dimensional thermoluminescent dosimetric system, newly developed at the IFJ PAN in Poland, and a clip-phantom consisting of a 100 mm × 100 mm × 5.3 mm PMMA plate with holes for clips placing at five irradiation angles (0, 30 45, 60 and 90°). The clip-phantom was irradiated with 68 MeV proton beam. The measurements were performed at different depths ranging from 6.3 to 24.8 mm water equivalent depth. The measurements of dose modification due to tantalum clips showed underdosing ranged from 4% to 32%. For those reasons ophthalmologist need to take this effect into account during clip surgery and medical physicist need to consider the position of the clips in treatment planning. [Copyright &y& Elsevier]

Abstract: Well known, widely applied high sensitive thermoluminescence (TL) detector LiF:Mg,Cu,P (MCP-N) was investigated. This paper analyses changes of the TL emission spectrum of MCP-N after irradiation with ultra high doses (up to 500 kGy). Spectral dependence of TL on dose is very complex especially in the region of very high doses (>1 kGy). As a general trend we found that the number of peaks increases with dose in the long-wavelength region indicating new types of recombination centres (RCs). Wavelength peak positions for increasing doses are quite stable. Only some of them show slight red-shift. [Copyright &y& Elsevier]