Among natural radionuclides, 226 Ra and 228 Ra intake can contribute considerably to radiological dose. Liquid scintillation counting offers a reliable and sensitive method for measurement in environmental (water) and biological (urine) matrices. While the determination of 226 Ra in water is quite simple, its determination in urine requires a suitable radiochemical procedure. In both cases an indirect measurement of daughter 222 Rn (with 218 Po and 214 Po) in secular equilibrium allows to determine 226 Ra activity. Moreover, in presence of anthropogenic radionuclides, a sequential separation of 228 Ra and 90 Sr in water has been developed, isolating daughters 228 Ac and 90 Y in secular equilibrium in the same vial.

A radiochemical analytical method, coupling different measurements techniques (alpha spectrometry, liquid scintillation counting and mass-spectrometry) for quantifying the content of the most significant plutonium and americium/curium isotopes in metal waste samples, is presented. The method based on the sequential determination of all the analytes of interest has the great advantage to perform the sample pre-treatment only once, resulting fast and cheap while maintaining sufficient selectivity and sensitivity. The mean values of radiochemical yields and the minimum detectable activities have been evaluated. Significant activity ratios between transuranic isotopes have been revealed and used to investigate the origin of the waste samples.

In order to determine radiostrontium with a satisfactory chemical yield, calculated by an external standard, and a low level of MDC a radioanalytical method has been optimized, for environmental and biological samples. Samples were mineralized and extracted by chromatography with prepackaged columns for Cherenkov effect measurement, via daughter radionuclide 90 Y, generated by 90 Sr. When also 89 Sr is present, 90 Y is eluted by the same column to subtract its contribution to total Cherenkov counts and determine separately 89 Sr and 90 Sr (via 90 Y) activity. By a fitting experimental data with an exponential equation the eventual presence of other β-emitter radionuclides was ascertained.

Two chromatographic extraction materials (DGA resin cartridges and TRU resin columns) for the determination of americium and curium in urine and faeces have been employed in this paper with two different procedures. 243 Am tracer has been successfully used as internal standard not only for americium but also for curium with both the chromatographic extractants. In addition, the sequential determination of plutonium and americium/curium isotopes has been tested and the differences between the two methods are presented. The mean values of radiochemical yields, the reproducibility and the minimum detectable activities have been measured and the accuracy tested by PROCORAD© intercomparison exercises.

[Sm-153]Sm-EDTMP is a radiopharmaceutical used in palliation cares of bone metastases. The purpose of this study is to provide an explicit description of [Sm-153]Sm-EDTMP pharmacokinetics, adopting a simple three-compartmental model with the analytical expressions calculating the rate constants and determining biodistribution parameters, like radiopharmaceutical uptake and clearance. This biokinetic model allowed us to calculate on an individual basis the dose to bone surface and to red bone marrow and to assess the degree of variability in dosimetric parameters using a fixed administered activity based only on patient weight.In this study twenty patients were enrolled and were treated with [Sm-153]Sm-EDTMP, administering a fixed activity per kilogram (37 MBq/kg); blood and urine samples were collected during 24 h post treatment. The median value of the administered activity was 2.7 GBq.Blood clearance confirmed that an aliquot of [Sm-153]Sm-EDTMP rapidly localizes and is retained in bone, while the remainder is rapidly cleared from the blood pool by the urinary system. Our data show a bi-exponential clearance from blood: the rapid component has a half life median value of 6 min (range: 2-24 min), while the slow one has a half life median value of 1.4 h (range: 0.6-5.8 h). Median value of the urinary excretion is 40 (range: 3-75) % of the administered activity.Our model shows the behaviour of a tracer which is distributed in the extracellular space of the body, localized in the skeleton and excreted via glomerular filtration. Half life median values of [Sm-153]Sm-EDTMP transferring between compartments, T-1/2 (blood -> ECF), T-1/2 (ECF -> blood) are 7.4 (range: 1.9-37) and 48 (range: 8-408) min, respectively. Median values of half lives of [Sm-153]Sm-EDTMP clearance through the urine and of uptake into bone are 1.0 (range: 0.1-6.0) and 1.6 (range: 0.6-9.0) h, respectively.Median value of red marrow absorbed dose is 2.1 (range: 0.7-3.5) Gy and 0.8 (range: 0.3-2.1) Gy/GBq, while median value of bone surface absorbed dose is 11.5 Gy (range: 5.0-18.4) and 4.4 (range: 2.3-14.3) Gy/GBq. It is remarkable that there is a really great biological variability within patients, especially considering the excreted activity. The cumulated activity in bone and red marrow doses were significantly higher in prostate cancer, where metastatic bone lesions are osteoblastic, than in breast cancer where metastatic bone lesions are osteolytic or mixed (lytic/blastic).The relevant biological variability in biodistribution and metabolism of [Sm-153]Sm-EDTMP suggests that the fixed administered activity based on patient weight is not sufficient to optimize the treatment and a better optimization would be reached by using a predictive dosimetry tailored to individual patient characteristics. (c) 2010 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The radiopharmaceutical [153Sm]Sm-EDTMP is administered for painful bone metastases with the standard dosage of 37 MBq/kg, without evaluation of patient individual characteristics. For a better dose estimate in vivo stability should be considered, because labelled and unlabelled samarium do not have the same metabolic pathway. We evaluated radiopharmaceutical in vitro stability, measuring the activity by beta and gamma spectrometry. Subsequently we verified in vivo stability on serial blood and urine samples. The percentage of the unlabelled radiopharmaceutical is high and, on the basis of radiochemical data as well as blood clearance and urine excretion, we calculated the main parameters for a preliminary biokinetic model.

SPECT studies are sensitive but inaccurate means through which to analyze small volumes such as, for instance, remnant tissues after thyroidectomy. We studied the relation between known volumes (0.1–10 cm3) and volumes measured with SPECT studies and using solutions of four different isotopes: 99mTc, 117mSn, 111In, 131I. The curves we determined were tested on SPECT images of two patients treated with 131I. Our work suggests the possibility to evaluate the small remnant mass using calibration curves specific to the system of image acquisition. However, it is necessary to extend the study to a larger number of patients.

Many biological samples (urines and faeces) have been analyzed by means of chromatographic extraction columns, utilizing two different resins (AG 1-X2 resin chloride and TRU), in order to detect the possible internal contamination of 239+240Pu and 241Am for some workers of a reprocessing nuclear plant in the decommissioning phase. The results obtained show on one hand the great suitability of the first resin for the determination of plutonium, and on the other, the great selectivity of the second one for the determination of americium.

During the radiation protection surveillance of exposed workers samples of urine and faeces were collected. Anion exchange chromatography was used for the separation of Pu. We investigated a technique to purify and separate Pu and Am isotopes using extraction chromatography with TRU resin. We tested different procedures to dissolve organic matter and eliminate interferences for chromatographic elution. At the end of the proces we have succeeded in electroplating the two radionuclides separately. We have also studied extraction chromatography with UTEVA resin to purify Pu isotopes and separate it from natural uranium radioisotopes, present in some biological samples. We validated a method for the determination of Pu in biological samples and a rather constant chemical yield and resolved peaks were obtained. The preliminary studies on TRU resin have indicated that it is possible to combine extraction and anion-exchange chromatography for analysing separately Pu and Am isotopes from the same sample aliquote.

Within the surveillance program of the gaseous effluents coming from the nuclear reprocessing plant EUREX of ENEA (Italian National Agency for New Technologies Energy and Environment, CR Saluggia) in the North of Italy, the content of some radionuclides is continuously monitored. The so-called 1AW high-activity liquid waste (HLLW) is the aqueous raffinate of the first cycle of PUREX extraction process which was the starting point of the reprocessing activity of some MTR and CANDU spent fuel elements. Nowadays, 1AW-HLLW is stored in five tanks placed inside the EUREX plant site. This paper describes the sampling and radioanalytical methods employed to determine the activities of 241Am, plutonium isotopes and 90Sr in the total suspended particulate material (TSP) of the 1AW tank primary ventilation air circuit.

Within the radiation protection physical surveillance program of some workers, involved in the decommissioning operations of a nuclear reprocessing plant of the Italian National Agency for New Technologies Energy and Environment, CR Saluggia (ENEA) in the north of Italy, some radiotoxicological analyses, on human urines, have been carried out, in order to determine the possible internal contamination of 241Am. After an in-depth study of a former extraction chromatographic method, based on the use of Microthene-722 supporting HDEHP, a more suitable method has been developed and adopted in our laboratory, based on the use of TRU-resin. This paper reports the results obtained with these two procedures as well as a comparison between them.

In this paper are presented the production methods for very "high specific activity" radionuclides (HSA-RN) of vanadium, manganese and thallium which have been developed in our laboratories for labelling different chemical forms of these elements present in the echo-systems in ultra-trace amounts, for metallo-toxicological and bio-kinetic studies. Use was made of both cyclotron and thermal nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. This kind of radionuclide is named No Carrier Added, NCA, and his specific activity, As is very high and can reach values close to the theoretical Carrier Free one, CF. The experimental determination of specific activity, chemical and radiochemical purities is mandatory for all these kinds of applications.

Very High Specific Activity RadioNuclides, HSARN, are a powerful tool to label a wide variety of chemical elements and compounds present in the biosphere in ultra-trace amounts. Medium and high Z radionuclides, can be produced by irradiation in light-ions accelerator and sometimes nuclear reactor. If the nuclear reaction product has atomic number different from irradiated target, it is possible separating the radioactive nuclide from irradiated target, without addition of isotopic carrier. These kinds of radionuclides are named No Carrier Added, NCA, and their specific activity is very high and can reach values close to the theoretical Carrier Free one. The true specific activity must be determined by use of very sensitive radioanalytical techniques. If a low isotopic dilution factor is obtained, these radiotracers; are used to label inorganic species and complexes of elements, which are presently introduced into the echo-systems by human activities. New production methods for NCA Pt, Ir, Au, Cu and Ga radiotracers are presented, with some details on radiochemistry and quality controls.

The concentrations (ng/m3) of more than 30 trace elements have been determined in the total air particulate of a rural-residential area in north Italy. By collecting the aerosols with multistage impactors the distribution of the trace elements in the different size-fractionated particles has been also investigated. The fine `inhalable' fraction with particles of less than 10 μm in equivalent aerodynamic diameter (PM10) as well as the subsequent finest `respirable' fractions with particles of 0–1.1 μm (alveolar), 1.1–4.6 μm (bronchial) and 4.6–9 μm (tracheo–pharynx) have been analyzed and evaluated. Apart from Pb, Cd and, in some cases, Ni and Cu which have been determined by ETAAS (electrothermal atomic absorption spectroscopy), all measurements have been carried out by instrumental neutron activation analysis (INAA).