Impact of new operational dosimetric quantities on individual monitoring services.

The new operational dosimetric quantities framework, proposed in the ICRU95 report, has stimulated the scientific community to start investigations that aim to assess its impact on radiation protection practices. As part of this effort, the present study describes an inter-comparison exercise among individual monitoring services (IMSs) on passive whole-body dosimetry. The inter-comparison is performed in terms of both the existing operational dose quantityHp(10)and its proposed replacementHp, to allow an evaluation of the actions that may be necessary to adapt dosimetry systems to the proposed quantity. For two of the tested IMSs, simple modifications to the detector response function, or the dose calculation algorithm, were sufficient to obtain results within acceptable limits. However, these approaches are not sufficient to give a level of performance comparable to that achieved in terms ofHp(10). This may require a modification to dosemeter design.

EURADOS STRATEGIC RESEARCH AGENDA 2020: VISION FOR THE DOSIMETRY OF IONISING RADIATION.

Since 2012, the European Radiation Dosimetry Group (EURADOS) has developed its Strategic Research Agenda (SRA), which contributes to the identification of future research needs in radiation dosimetry in Europe. Continued scientific developments in this field necessitate regular updates and, consequently, this paper summarises the latest revision of the SRA, with input regarding the state of the art and vision for the future contributed by EURADOS Working Groups and through a stakeholder workshop. Five visions define key issues in dosimetry research that are considered important over at least the next decade. They include scientific objectives and developments in (i) updated fundamental dose concepts and quantities, (ii) improved radiation risk estimates deduced from epidemiological cohorts, (iii) efficient dose assessment for radiological emergencies, (iv) integrated personalised dosimetry in medical applications and (v) improved radiation protection of workers and the public. This SRA will be used as a guideline for future activities of EURADOS Working Groups but can also be used as guidance for research in radiation dosimetry by the wider community. It will also be used as input for a general European research roadmap for radiation protection, following similar previous contributions to the European Joint Programme for the Integration of Radiation Protection Research, under the Horizon 2020 programme (CONCERT). The full version of the SRA is available as a EURADOS report (www.eurados.org).

EURADOS education and training activities.

This paper provides a summary of the Education and Training (E&T) activities that have been developed and organised by the European Radiation Dosimetry Group (EURADOS) in recent years and in the case of Training Courses over the last decade. These E&T actions include short duration Training Courses on well-established topics organised within the activity of EURADOS Working Groups (WGs), or one-day events integrated in the EURADOS Annual Meeting (workshops, winter schools, the intercomparison participants' sessions and the learning network, among others). Moreover, EURADOS has recently established a Young Scientist Grant and a Young Scientist Award. The Grant supports young scientists by encouraging them to perform research projects at other laboratories of the EURADOS network. The Award is given in recognition of excellent work developed within the WGs' work programme. Additionally, EURADOS supports the dissemination of knowledge in radiation dosimetry by promoting and endorsing conferences such as the individual monitoring (IM) series, the neutron and ion dosimetry symposia (NEUDOS) and contributions to E&T sessions at specific events.

COMPARISON OF PADC NEUTRON DETECTORS FROM DIFFERENT SUPPLIERS.

The objective of this study was to compare poly-allyl diglycol carbonate (PADC) track detectors from different suppliers for linear energy transfer (LET) spectrometry and neutron dosimetry. PADCs are commonly used for passive personal neutron dosimetry, where a common approach is to couple the PADC with a plastic radiator to generate secondary charged particles. The neutron dose can be estimated using the track density or the average LET of the secondary particles. The characterisation of PADC in terms of LET spectrometric capability and neutron sensitivity was previously performed using PADC from Intercast S.r.l., Parma, Italy, but this company stopped the production. Since it is common experience that material from different suppliers can have different properties, it became necessary to perform a comparison of PADCs from different suppliers with the Intercast material. The study permits to compare the reading procedures used at Politecnico di Milano and at the Paul Scherrer Institute.

A new version of the LUPIN detector: improvements and latest experimental verification.

LUPIN-II is an upgraded version of LUPIN, a novel rem counter first developed in 2010 specifically conceived to work in pulsed neutron fields (PNFs). The new version introduces some modifications that improve the performance of the detector, in particular extending its upper detection limit in PNFs. This paper discusses the characteristics and the performance of the instrument. Measurements have been carried out in radiation fields characterized by very different conditions: the detector has first been exposed in PNFs with intensity up to 5 µSv per burst, where it could keep the H*(10) underestimation below 20% up to 500 nSv per burst. It has then been tested in operational conditions around particle accelerators, where it has shown performances similar to that of ionization chambers. Its proper functioning has also been verified in high energy mixed fields, where the experimental results matched the Monte Carlo predictions. Its neutron/photon discrimination capability has been tested in a steady-state photon field where, via an innovative technique based on a threshold set on the derivative of the current signal, it was capable of rejecting a photon H*(10) rate of about 25 mSv/h, and in a mixed neutron/photon field, where a time-based discrimination method was employed.

Evaluation of a personal and environmental dosemeter based on CR-39 track detectors in quasi-monoenergetic neutron fields.

In this paper, the evaluation of the dosimetric capability of a detector based on a CR-39 solid-state nuclear track detector coupled to a 1 cm thickness of PMMA radiator was made with the aim of understanding the applicability of this technique to personal and environmental neutron dosimetry. The dosemeter has been exposed to monoenergetic and quasi-monoenergetic neutron beams at PTB in Braunschweig, Germany and at Ithemba Laboratories, in Faure, South Africa, with peak energies ranging from 0.565 to 100 MeV. The results showed a response that is almost independent of the neutron energy in the whole energy range.

A comparison of the response of PADC neutron dosemeters in high-energy neutron fields.

Within the framework of the EURADOS Working Group 11, a comparison of passive neutron dosemeters in high-energy neutron fields was organised in 2011. The aim of the exercise was to evaluate the response of poly-allyl-glycol-carbonate neutron dosemeters from various European dosimetry laboratories to high-energy neutron fields. Irradiations were performed at the iThemba LABS facility in South Africa with neutrons having energies up to 66 and 100 MeV.

Sensitivity study of CR39 track detector in an extended range Bonner sphere spectrometer.

Bonner sphere spectrometers (BSS) are being used widely in neutron spectrometry since 1960. The response to neutrons of these moderating detectors spans over a broad energy range. This work discusses the measurement of the sensitivity of an extended range BSS hosting a CR39 nuclear track detector coupled to a boron converter. Two kinds of boron converters were tested, the first made by natural boron and a second one enriched in (10)B. The BSS response functions were calculated with Monte Carlo simulation using the MCNPX 2.4.0. and the FLUKA codes.

The evaluation of uncertainty in low-level LSC measurements of water samples.

The uncertainty in measurements of gross alpha and beta activities in water samples by liquid scintillation counting with alpha/beta discrimination has been evaluated considering the problems typical of low-level measurements of environmental samples. The use of a pulse shape analysis device to discriminate alpha and beta events introduces a correlation between some of the input quantities, and it has to be considered. Main contributors to total uncertainty have been assessed by specifically designed experimental tests. Results have been fully examined and discussed.

Incidence and prognostic significance of karyotype abnormalities in de novo primary myelodysplastic syndromes: a study on 331 patients from a single institution.

The impact of clinical parameters, International Prognostic Scoring System (IPSS) scores/cytogenetic categories, and some single cytogenetic defects on overall survival (OS) and time to myelodysplastic syndromes (MDS)/AML progression (progression-free interval (PFI)) was evaluated in 331 MDS patients. Statistical analysis demonstrated that OS and PFI were significantly affected by all these parameters. Since single 7q- showed a better survival than the poor IPSS cytogenetic category (P=0.009), it was considered as a new prognostic entity ('modified IPSS categories'). In multivariate analysis OS was significantly influenced by age, marrow blast cell percentage, number of cytopenias and either modified or standard IPSS cytogenetic categories; hazard ratios for MDS/AML progression were influenced by all the former, except for age and cytopenias. Multivariate analysis of del(7)(q31q35) confirmed the results of univariate analysis, but the Akaike Information Criterion showed no difference in evaluating OS and PFI between the modified and standard IPSS cytogenetic grouping. In conclusion, (i) chromosome defects as grouped by IPSS and blast cell percentage are the most relevant parameters for predicting OS and PFI; (ii) the prognostic power of the IPSS cytogenetic grouping is not ameliorated by the introduction of del(7)(q31q35) as a new entity; (iii) complex karyotypes have a prognostic value independent of blast cell percentage.

Evaluation of etching correction factor for LR115 cellulose nitrate films from track parameters.

LR115 cellulose nitrate films efficiency is strongly dependent on the conditions of etching. In this paper a new method to evaluate a correction factor for this effect is given. The film is scanned with an high-resolution scanner, the diameter of the tracks is measured, and the correction factor is calculated from the average diameter of the tracks. The sensitivity of the film is found to have a linear dependence on the average diameter, and the classical correction, based on the residual thickness, can be substituted by a method based on average track diameter.

Feasibility study of a personal dosemeter based upon silicon diodes used in remote controlling.

The availability of low cost personal dosemeters is very important for routine worker monitoring. The aim of this work is to evaluate the performance of commercial silicon diodes, commonly used for infrared communication, as a personal radiation monitor. The instrument prototype was characterised both as an area monitor and a personal monitor. Instrument response was measured in the energy range form 37 keV to (60)Co energy. The angular response was also evaluated too.

Uncertainties evaluation for electrets based devices used in radon detection.

In recent years uncertainty evaluation in measurements has achieved great importance. National and international standards offer guidelines to evaluate uncertainties, but these procedures are, until now, not well understood by the operators. This is because of the fact that a detailed uncertainty evaluation is not an easy operation and a standard rule to apply in all cases is not available. Every measurement procedure has its own uncertainty evaluation. In this work, attention is focused upon the electret ion chambers (EIC), widely used in radon concentration measurements. Measurements of gamma radiation sensitivity are performed in a secondary standard calibration laboratory and measurement of radon concentration sensitivity is performed in a radon chamber 0.8 m3 in volume. Raw data are analysed to evaluate the calibration factors and the combined uncertainties are determined. The aim of the work is to give a practical method to assess the uncertainty of a radon measurement.

Uncertainty evaluation of radon measurements with LR115 detector and spark counter.

To evaluate the uncertainties for nuclear track detectors used in radon measurements, a full understanding is required of the physical phenomena involved and the behaviour of the instruments utilised in the measuring process. As it concerns the LR115 nuclear track detector, an overall evaluation of uncertainty was given. It was assessed taking into account different contributions and determining their relative weights. Since such detectors are often read by a spark counter device, a model to describe its behaviour was developed and a saturation factor was estimated. Its expression and its associated uncertainty are given. Hence, it has been possible to draw a calibration curve, in which all the uncertainty sources have been considered.

Is FISH a relevant prognostic tool in myelodysplastic syndromes with a normal chromosome pattern on conventional cytogenetics? A study on 57 patients.

Conventional cytogenetics (CC) at clinical diagnosis shows a normal karyotype in 40-60% of de novo myelodysplastic syndromes (MDSs). Fluorescence in situ hybridization (FISH) might detect occult aberrations in these patients. Therefore, we have used FISH to check 57 MDS patients who were karyo-typically normal on CC. At clinical diagnosis, FISH revealed a clonal abnormality in 18-28% interphase cells from nine patients, five of whom also presented the same defect on metaphase FISH. In five out of nine patients, the occult defect effected a change in the international prognostic scoring system (IPSS). An abnormal FISH pattern was significantly correlated with marrow blast cell percentage (P<10(-3)) and IPSS (P<10(-3)). Patients with an occult abnormality showed an overall survival and event-free survival significantly inferior in comparison to those of patients with normal FISH (P<10(-3), P<10(-3)). Death and AML progression were 15- and eight-fold more frequent in FISH abnormal patients. In conclusion, occult defects (1) are revealed in about 15% of CC normal MDS patients, (2) are overlooked by CC either because of the poor quality of metaphases or their submicroscopic nature, (3) are clinically relevant as they may cause a change in the IPSS category and may identify a fraction of CC normal patients with an unfavorable clinical outcome.

Acute myeloid leukemia (AML) having evolved from essential thrombocythemia (ET): distinctive chromosome abnormalities in patients treated with pipobroman or hydroxyurea.

ET is a chronic myeloproliferative disorder rarely evolving into AML, sometimes preceded by a myelodysplastic syndrome (MDS). Such transformations mostly occur in patients treated with radiophosphorous ((32)P) or alkylating agents, especially busulfan. Recently, concern has also arisen about the long-term safety of hydroxyurea (HU). Pipobroman (PI), a well tolerated and simple to use drug, constitutes a valid alternative to those cytoreductive treatments. The present study reports on 155 ET patients treated at our institution from 1985 to 1995, and monitored until December 2000. A good control of thrombocytosis was achieved with PI as the only treatment in 106 patients and with HU in 23 patients. Twenty-six patients received no treatment. After a median follow-up of 104 months, seven patients (four treated with HU, and three with PI) developed AML whereas one patient treated with PI developed MDS. A significant difference in progression-free survival was observed between HU- and PI-treated patients (P = 0.004). A short-arm deletion of chromosome 17 was most frequently detected in HU-treated patients, while a long-arm trisomy of chromosome 1 and a monosomy 7q were seen in PI-treated patients. No TP53 mutation was discovered in the six patients studied (two HU-treated and four PI-treated). We conclude that these cytogenetic abnormalities are not linked to the natural history of the disease, but rather that they might be induced by the cytoreductive treatment.

Translocation (8;16) in a patient with acute myelomonocytic leukemia, occurring after treatment with fludarabine for a low-grade non-Hodgkin's lymphoma.

We describe a 65-year old woman who developed a t(8;16)(p11;p13) positive acute myeloid leukemia (AML)-M4 without a prior myelodysplasia thirty-six months after a low-grade non-Hodgkin's lymphoma treated with alkylating agents (chlorambucil and cyclophosphamide) and fludarabine, a purine analog with a significant activity in lymphoproliferative disorders. The t(8;16)(p11;p13) is present in 0.4% of AML of M4-M5 cytotype. In the present case it was identified by conventional cytogenetics; involvement of the MOZ and CBP genes was demonstrated by fluorescence in situ hybridization, but not by reverse transcription polymerase chain reaction. The patient died of sepsis after the first course of induction chemotherapy. This is the first t(8;16) AML-M4 arising after fludarabine treatment of which the leukemogenic role in our case is very difficult to ascertain. Most t(8;16) t-AML cases had received anthracyclines with or without cyclophosphamide; none was ever administered chlorambucil. Our patient was never given anthracyclines and the cumulative doses of chlorambucil and cyclophosphamide employed were low.

Trisomy 11 and a complex t(11;11;22) in a patient with acute myelomonocytic leukemia (AML-M4) following myelodysplasia (MDS): a cytogenetic study of a mechanism of leukemogenesis.

We describe a 73-year-old man diagnosed with acute myelomonocytic leukemia (AML-M4) following myelodysplasia with trisomy 11 and with a t(11;11;22). This is the first case with both abnormalities present in the same cells and with the t(11;11;22) involving a chromosome 11 already duplicated at 11q23. This band contains the MLL gene that undergoes partial tandem duplication in patients with +11, which is "promiscuous," being translocated with a large number of genetic partners. Our patient had a complex karyotype that was completely defined by in situ hybridization. This technique demonstrated that the t(11;11;22) derivative with a duplication of band 11q23 carried from three to four copies of MLL. Two copies of the gene were close to each other and centromeric to the break-point region. Therefore, a partial tandem duplication of the MLL gene might have happened before the occurrence of t(11;11;22). Considering the associated chromosome defects, the monosomy for the long arm of chromosome 7, due to an unbalanced translocation t(7;17), further underlines the possibility that a partial tandem duplication of the MLL gene might have taken place.