Role of damaged mitochondrial transfer in alpha-particle generator Pb radiation-induced bystander effect.

Pb, a promising alphaparticle generator of Bi, has aroused much interest as a therapeutic radionuclide. For the development of targeted alpha therapy (TAT), it is important to determine the contribution of targeted effects in irradiated cells, and also of non-targeted effects in non-irradiated bystander cells. Currently, the critical roles of mitochondrial transfer in cellular crosstalk have garnered significant attention.

Rapid determination of Tc in water samples using Ti(OH)-TcO co-precipitation and TK200 resin by liquid scintillation counting.

A novel method for the determination of Tc in water samples was developed using stable Re as a chemical yield tracer and TiCl as a reducing agent. The influences of several experimental parameters, including TiCl concentration, HCl concentration and reaction time, on the reduction of TcO and ReO as well as Ti(OH)-TcO-ReO co-precipitation were investigated. Tc(VII) and Re(VII) retained on TK200 resin were effectively eluted by 5 mL of 1 mol/L NHSCN, which can be directly mixed with the scintillation cocktail for liquid scintillation counting.

Simultaneous determination of actinides and Sr in large-size soil and sediment samples.

A simultaneous analytical method for sequential separation and determination of actinides and Sr in large-size environmental samples has been developed. In this method, successive co-precipitation steps were firstly conducted to remove matrix elements, then sequential column separation method was applied for simultaneous separation and purification of actinides and Sr/Y. By using vacuum box technology, the total analytical time was minimized and batch processing allowed analyzing 12 samples in four days.

Direct analysis of Pb in drinking water by liquid scintillation counting after sulfate precipitation.

Lead-210 in drinking water can be rapidly determined by liquid scintillation counting (LSC) using a new sulfate precipitation method. In this method, Pb was first preconcentrated from water using iron hydroxide co-precipitation followed by sulfate precipitation to decontaminate most of non-alkaline earth elements. The Pb in the sulfate precipitate was then dissolved in strong alkaline solution, while alkaline earth elements (Sr, Ba, Ra) were separated as the sulfate/carbonate precipitate.

Effects of sodium salicylate on the determination of Lead-210/Bismuth-210 by Cerenkov counting.

Due to the nature of Cerenkov radiation and instrumental limitations, detection efficiencies of Bi by Cerenkov counting are generally quite low (~15%). Sodium salicylate, acting as a wavelength shifter, has been used to improve the detection efficiency of Cerenkov photons. In this study, we found that the addition of sodium salicylate could significantly increase the counting efficiencies of Pb/Bi in aqueous samples.

Sequential analyses of actinides in large-size soil and sediment samples with total sample dissolution.

There is a growing demand for the determination of actinides in soil and sediment samples for environmental monitoring and tracing, radiological protection, and nuclear forensic reasons. A total sample dissolution method based on lithium metaborate fusion, followed by sequential column chromatography separation, was developed for simultaneous determination of Pu, Am and Cm isotopes in large-size environmental samples by alpha spectrometry and mass spectrometric techniques. The overall recoveries of both Pu and Am for the entire procedure were higher than 70% for large-size soil samples.

Method of Polonium Source Preparation Using Tellurium Microprecipitation for Alpha Spectrometry.

A thin-layer source for the counting of polonium isotopes by alpha spectrometry can be rapidly prepared using microprecipitation with tellurium. Polonium was first coprecipitated with the reduction of tellurium by stannous chloride, followed by microfiltration onto a membrane filter for counting. This microprecipitation method is faster, cheaper, and more convenient than the traditional spontaneous deposition method, with an excellent Po recovery (>90%) under optimal conditions.

Determination of Tc in fresh water using TRU resin by ICP-MS.

Technetium-99 (Tc) determination at trace level by inductively coupled plasma mass spectrometry (ICP-MS) is challenging because there is no readily available appropriate Tc isotopic tracer. A new method using Re as a recovery tracer to determine Tc in fresh water samples, which does not require any evaporation step, was developed. Tc(VII) and Re(VII) were pre-concentrated on a small anion exchange resin (AER) cartridge from one litre of water sample.

An improved method for the rapid determination of Sr in cow's milk.

An improved method was developed to rapidly determine strontium-90 (Sr) in cow's milk samples in the event of a nuclear emergency. To perform this method, no heating or ashing steps were needed and all of the material used was disposable. Stable Sr tracer was added to each 40 mL milk sample.

Rapid determination of radium-224/226 in seawater sample by alpha spectrometry.

A new radiochemical separation method has been developed for rapid determination of alpha-emitting radium isotopes in seawater samples. This method can be applied for the measurement of Ra in seawater samples when Ra is used as tracer for chemical recovery correction. Likewise, Ra can also be added as tracer for the determination of Ra in seawater sample.

Determination of Atto- to Femtogram Levels of Americium and Curium Isotopes in Large-Volume Urine Samples by Compact Accelerator Mass Spectrometry.

Ultralow level analysis of actinides in urine samples may be required for dose assessment in the event of internal exposures to these radionuclides at nuclear facilities and nuclear power plants. A new bioassay method for analysis of sub-femtogram levels of Am and Cm in large-volume urine samples was developed. Americium and curium were co-precipitated with hydrous titanium oxide from the urine matrix and purified by column chromatography separation.

Rapid and simultaneous determination of Strontium-89 and Strontium-90 in seawater.

A rapid method has been developed for the direct determination of radiostrontium ((89)Sr and (90)Sr) released in seawater in the early phase of an accident. The method employs a fast and effective pre-concentration of radiostrontium by Sr-Ca co-precipitation followed by separation of radiostrontium using extraction chromatography technique. Radiostrontium is effectively separated in the presence of excessive dominant salts of seawater.

An emergency bioassay method for (210)Po in urine.

A rapid method was developed to efficiently measure (210)Po in urine samples in an emergency situation. Polonium-210 in small urine samples (10 mL) was spontaneously deposited on a stainless steel disc in 1 M HCl at room temperature for 4 h in a polyethylene bottle. The metallic disc was then counted for 4 h by alpha spectrometry.

EURADOS intercomparison on emergency radiobioassay.

Nine laboratories participated in an intercomparison exercise organised by the European Radiation Dosimetry Group (EURADOS) for emergency radiobioassay involving four high-risk radionuclides ((239)Pu, (241)Am, (90)Sr and (226)Ra). Diverse methods of analysis were used by the participating laboratories for the in vitro determination of each of the four radionuclides in urine samples. Almost all the methods used are sensitive enough to meet the requirements for emergency radiobioassay derived for this project in reference to the Clinical Decision Guide introduced by the NCRP.

Determination of (210)Po in drinking water and urine samples using copper sulfide microprecipitation.

Polonium-210 ((210)Po) can be rapidly determined in drinking water and urine samples by alpha spectrometry using copper sulfide (CuS) microprecipitation. For drinking water, Po in 10 mL samples was directly coprecipitated onto the filter for alpha counting without any purification. For urine, 10 mL of sample was heated, oxidized with KBrO3 for a short time (∼5 min), and subsequently centrifuged to remove the suspended organic matter.

Five-column chromatography separation for simultaneous determination of hard-to-detect radionuclides in water and swipe samples.

There is a growing demand for the rapid determination of hard-to-detect radionuclides in environmental and biological samples for environmental monitoring, radiological protection, and nuclear forensic reasons. A new method using five-column chromatography separation has been developed for the simultaneous determination of Pu, Np, Th, U, Am, Cm, Pm, Y, and Sr isotopes, as well as iron-55, by inductively coupled mass spectrometry (ICPMS), α spectrometry, Čerenkov and liquid scintillation (LS) counting. Spiked swipe and water samples as well as proficient testing water standards were analyzed to validate the separation procedure, and the results are in good agreement with the expected values.

Rapid preparation of polonium counting sources for alpha spectrometry using copper sulfide microprecipitation.

Thin-layer polonium (Po) sources for alpha spectrometry counting can be rapidly prepared using copper sulfide (CuS) microprecipitation. Polonium was coprecipitated with CuS, filtered onto Eichrom Resolve filters, and counted. This simple procedure is faster, cheaper, and more convenient than traditional spontaneous plating on metallic discs, and similar yields were obtained (80-90%).

Optimisation of nasal swab analysis by liquid scintillation counting.

When responding to an emergency radiological incident, rapid methods are needed to provide the physicians and radiation protection personnel with an early estimation of possible internal dose resulting from the inhalation of radionuclides. This information is needed so that appropriate medical treatment and radiological protection control procedures can be implemented. Nasal swab analysis, which employs swabs swiped inside a nostril followed by liquid scintillation counting of alpha and beta activity on the swab, could provide valuable information to quickly identify contamination of the affected population.

Rapid determination of 226Ra in urine samples.

A new radiochemical separation method has been developed for rapid analysis of (226)Ra in urine samples. In this method, radium is separated from urine matrix using cation and anion exchange column chromatography. A (224)Ra tracer is added, together with its parent in the (228)Th standard, for chemical recovery correction.

An emergency bioassay method for actinides in urine.

A rapid bioassay method has been developed for the sequential measurements of actinides in human urine samples. The method involves actinide separation from a urine matrix by co-precipitation with hydrous titanium oxide (HTiO), followed by anion exchange and extraction chromatography column purification, and final counting by alpha spectrometry after cerium fluoride micro-precipitation. The minimal detectable activities for the method were determined to be 20 mBq L(-1) or less for plutonium, uranium, americium and curium isotopes, with an 8-h sample turn-around time.

Rapid urinary output normalization method using specific gravity.

Spot urine samples are often taken for emergency radiobioassay to provide a quick dose assessment for contaminated individuals. The subsequent dosimetric analysis requires a urinary output normalization method to adjust spot sampling to daily urine excretion. A rapid specific gravity method that was developed for 24-h urinary output correction is described.

Canada's efforts in developing capabilities in radiological population monitoring.

Population monitoring is an important component of radiological and nuclear emergency preparedness and response. Since 2002, Canada has been investing in developing national capabilities in radiological population monitoring. This paper summarizes Canada's efforts in developing methods and techniques in biological dosimetry and in vivo and in vitro bioassay techniques.

Requirements for radiation emergency urine bioassay techniques for the public and first responders.

Following a radiation emergency, the affected public and the first responders may need to be quickly assessed for internal contamination by the radionuclides involved. Urine bioassay is one of the most commonly used methods for assessing radionuclide intake and radiation dose. This paper attempts to derive the sensitivity requirements (from inhalation exposure) for the urine bioassay techniques for the top 10 high-risk radionuclides that might be used in a terrorist attack.