Disposal Of Radioactive Materials Research Articles

Studying microbially induced corrosion on glass using ToF-SIMS.

Microbially induced corrosion (MIC) is an emerging topic that has huge environmental impacts, such as long-term evaluation of microbial interactions with radioactive waste glass, environmental cleanup and disposal of radioactive material, and weathering effects of microbes. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), a powerful mass spectral imaging technique with high surface sensitivity, mass resolution, and mass accuracy, can be used to study biofilm effects on different substrates. Understanding how to prepare biofilms on MIC susceptible substrates is critical for proper analysis via ToF-SIMS. We present here a step-by-step protocol for preparing bacterial biofilms for ToF-SIMS analysis, comparing three biofilm preparation techniques: no desalination, centrifugal spinning (CS), and water submersion (WS). Comparisons of two desalinating methods, CS and WS, show a decrease in the media peaks up to 99% using CS and 55% using WS, respectively. Proper desalination methods also can increase biological signals by over four times for fatty acids using WS, for example. ToF-SIMS spectral results show chemical compositional changes of the glass exposed in a Paenibacillus polymyxa SCE2 biofilm, indicating its capability to probe microbiologically induced corrosion of solid surfaces. This represents the proper desalination technique to use without significantly altering biofilm structure and substrate for ToF-SIMS analysis. ToF-SIMS spectral results showed chemical compositional changes of the glass exposed by a Paenibacillus bacterial biofilm over 3-month inoculation. Possible MIC products include various phosphate phase molecules not observed in any control samples with the highest percent increases when experimental samples were compared with biofilm control samples.

Efficient capture of palladium from nuclear wastewater by the sulfide and thiol modified covalent organic framework

The effective separation of palladium isotopes from high-level radioactive waste offers significant advantages, not only in ensuring the safe management and disposal of radioactive materials but also in addressing the scarcity of noble metals. In this study, a covalent organic framework (COF-SSH) modified with thiol and thioether groups is synthesized for the purpose of palladium separation. The experimental results demonstrate that the adsorption of Pd(II) occurs rapidly, reaching equilibrium within just 10 min. The adsorption isotherm for Pd(II) aligns well with the Langmuir model, revealing a maximum adsorption capacity of 420.2 mg/g at 3 M HNO3. Through Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), and Density Functional Theory (DFT) analyses, the interaction between Pd and S atoms as being crucial for the adsorption process is identified. Moreover, COF-SSH exhibits exceptional selectivity for Pd(II) in simulated nuclear wastewater and maintains its performance throughout six consecutive adsorption and regeneration cycles. These results suggest that COF-SSH is a promising adsorbent for palladium separation, offering both acid resistance and high selectivity, making it a valuable candidate to the field of radioactive waste management and noble metal recovery.

Numerical Simulation on Dispersion of Hydrogen Leaked in Particle Layers of Glass Beads and Soil

In order to understand the dispersion of hydrogen (H2) leaked in packed beds of nonporous/porous particles in a partially open space practically, the dispersion of H2 in the particle layers of glass beads and soil was analytically studied using a computational fluid dynamics code to be compared with the experiments and to elucidate the effects of the particle layer. The packed beds in the partially open space can be considered as a basic model for all processes of transfer, treatment, storage, and disposal of radioactive materials containing fuel debris in the decommissioning of nuclear facilities after a severe accident. The H2 flowing out from a single leak point in the particle layer of nonporous glass beads was affected by buoyancy around the leak point and diffused directly above the leak point in an elliptical shape faster than in the horizontal direction. After that, when it reached the air layer in the head space above the particle layer, the H2 spread horizontally, formed a large concentration gradient near the boundary between the particle layer and the air layer, and further diffused in the air layer until the H2 concentration became about 1/3 or less of the concentration near the surface of the particle layer. When the particle diameters were 512 μm and 1200 μm, this tendency was more pronounced when the porosity was the same and the particle diameter was smaller. The calculations largely reproduced the experimental concentration distributions. When the particle layer was porous decomposed granite soil, the diffusion behavior of H2 in the particle layer proceeded in the same manner as in the case of the glass beads. However, a large concentration gradient was formed near the boundary between the particle layer and the air layer, and then H2 diffused in the air layer until the H2 concentration became below the lower combustion limit. It was suggested through sensitivity analysis that the air permeability coefficient had a large effect on the time course of the H2 concentration distribution. Based on this information, we further simulated H2 behavior in the vessel containing the H2 leaked particle layer. By inserting multiple vent pipes without considering H2 generation distribution and particle properties in the particle layer, H2 accumulated from one pipe was discharged by buoyancy without depending on the H2 generation distribution and particle properties in the particle layer and air flowed in from the other pipe. It was suggested that such a natural ventilation process would reduce the H2 concentration in the container.

Radiological risk assessment method for the interim storage of radioactive materials

Safe storage of radioactive materials is based on three universal radiation protection principles. Justification, optimization and dose limits are applicable to the risk assessment, acknowledging the hazards in each procedure of delivery, usage, storage and disposal of radioactive materials. Failure Modes and Effects Analysis method (FMEA) is developed for the risk evaluation of common practices. In this work FMEA is exploited for the radiological risk assessment in practices using radioactive materials. In addition, the radiological hazard of fire is studied, in order to classify its severity for different examples of radioactive materials inventories. The severity of the hazard, the likelihood and the detectability of its occurrence are exploited for classifying the associated risk. Appropriate measures that should be taken for the emergency preparedness and response are taken into account in order to reduce the Risk Priority Number (RPN). Scenarios of external exposure, skin contamination and inhalation are investigated, in order to calculate the received doses, for workers and members of the public. The outcomes of the analysis indicate low or medium severity of the risks for most of the examined practices, especially under the implementation of the appropriate measures, like: controlled access of the facilities, records keeping for delivery, usage, storage and disposal of radioactive materials; presence of fire detectors and extinguishers; and removal of flammable materials from the vicinity of the radioactive materials.

Effects of Vent Size and Wind on Dispersion of Hydrogen Leaked in a Partially Open Space: Studies by Numerical Analysis

To understand the dispersion of hydrogen (H2) leaked in a partially open space practically, which can be considered as a basic model for all processes of transfer, treatment, storage, and disposal of radioactive materials containing fuel debris in the decommissioning of nuclear facilities after a severe accident, this paper uses a computational fluid dynamics code to study analytically the effects of vent size and outer wind on H2 dispersion. The paper adopts the experimental Hallway model, which has a H2 release hole on the ceiling, one vent on the roof (Roof vent), and one vent on the side (Door vent). Air flows in the model (room) from the Door vent while H2 is discharged outside from the Roof vent. The discharged (outflow) amount of H2 increases in conjunction with the air inflow when the size of the Roof and/or Door vents is increased, and then vice versa. The effect of wind depends on the direction to the Door vent: Wind from the same direction as the Door vent promotes H2 discharge while wind from the opposite direction suppresses it. The dispersion behavior characteristics of indoor leaked H2 are clarified for comparing model tests with the same Froude number and different scales. It is found from the analysis results of comparing model tests with the same Froude number and different scales that when H2 leaks into the room and diffuses to the air, the flow generated by the buoyancy of mixed gas creates the stack effect, which causes natural ventilation by drawing in air from the outside through the vent. In addition, it is speculated that the H2 concentration decreases after its leak by quickly mixing with air that flows in from the vents and reaches the floor due to the Coanda effect, which is the effect of the free jet being drawn to a nearby wall.

Considerations for Establishing a Theranostic Treatment Site

<h3>Purpose/Objective(s)</h3> Here we present guidance to radiation oncology centers in establishing theranostic treatments. Theranostics are radiopharmaceuticals with diagnostic and therapeutic attributes. They are composed of a vector which binds to a target receptor, a linker which connects the vector to the radioisotope and a radioisotope. Theranostics treatment is a multifaceted process including radiation safety, licensing, clinical workflow and supply management. <h3>Materials/Methods</h3> Radiation safety in theranostics requires the management of personnel/patient radiation exposure, decay in storage and disposal of radioactive materials. Decay in storage must satisfy NRC § 35.92. A dedicated toilet is preferable due to renal excretion. NRC § 20.2003 renders excreta from patients exempt from sanitary sewerage restrictions. ALARA-consistent protocols must be implemented to manage personnel, patient and caregiver exposures including: internal contamination, patient education, discharge criteria, and management of time/distance/shielding during preparation, treatment and cleanup. Licensing: An Authorized User and a Radioactive Material License are required and activity usage limits for each isotope must be consistent with the licensing for the site. Table 1 lists common isotopes to consider with varying radiation safety, licensing, etc. requirements. Staff education is paramount for clinical workflow and supply management. Protocols, checklists, and documentation for the concerted efforts of CNMTs, nurses, physics, and attending are imperative for procedures and contingencies. Required equipment: infusion pumps, specialized tubing/connectors, pharmaceuticals, amino acids, contamination control, spill kits, dedicated treatment room, remote patient monitoring, radiation monitoring, radiation survey tools, radiation shielding, dose calibrator, and imaging equipment (e.g., SPECT, Gamma camera, PET CT, etc.). <h3>Results</h3> Adherence to these guidelines allowed successful treatment of patients with ¹⁷⁷Lu, ²³³Ra and ⁹⁰Y. Dosimetry and radiation survey data confirm successful implementation of rad safety procedures. ¹⁷⁷Lu – treated patients were surveyed at one meter hourly to assess uptake/excretion of ¹⁷⁷Lu and to confirm safe discharge. Data from radiation monitoring and radiation surveys for treatments will be presented. <h3>Conclusion</h3> A theranostics program can be safely established through an organized effort which considers the factors presented here – radiation safety, licensing, clinical workflow and supply management.

Magnetic nanoparticle technique versus radioisotope technique in detection of sentinel lymph node in early breast cancer: a systematic review and meta-analysis

Sentinel lymph node biopsy is the standard technique to stage the axilla in early breast cancer. The gold standard is the dual technique of radioisotope and blue dye injection. The drawbacks of dual technique include handling and disposal of radioactive material. Equally reliable, user and patient friendly, magnetic tracer super paramagnetic iron oxide, was compared with the radioisotope tracer in detection of Sentinel lymph node in a clinically node negative axilla in early breast cancer in this meta-analysis, with emphasis on the utility and safety of both techniques. PubMed, Medline were searched from April 2015 to October 2019. 1395 patients’ data was included from seven homogenous studies in this meta-analysis. A statistical analysis was performed using STATA 16.1 version for sentinel lymph node detection rate using standard technique, magnetic tracer technique and both techniques. Ratio of successes and failures of the outcomes was measured and analysed. A paired two sample ‘Z’ test was performed to compare between the standard technique and magnetic tracer techniques. The standardised mean difference of ratio of success rate between two techniques was; 1.013334 with a p value of 0.3136.The standardised mean difference of ratio of failure rate between two techniques was 1.016667, with a p value of 0.3132. Success and failure rate showed statistically no significant difference between the two techniques. This two-way analysis with paired two sample ‘Z’ test confirms that neither standard technique nor magnetic tracer techniques are superior or inferior to each other.

The Perils of a Half-Built Bridge: Risk Perception, Shifting Majorities, and the Nuclear Power Debate

Much of the risk perception literature relies on the important but unstated assumption that manipulating public opinion to conform to scientific assessments of risk could help the public and, in turn, policymakers make better decisions about whether and how to regulate. This paper argues that the assumption fails in the context of certain multilayered risks, or risks that pose tiered policy choices - not just whether to regulate in the first instance, but how to respond to derivative risks arising from the first set of regulatory changes. Examining the debate about the role of nuclear power in the United States' approach to climate change, the paper observes that first- and second-tier risks often differ in character, or require different types of regulatory solution (market-based versus command-and-control). Due to these variations, the public may hold starkly different views about regulation of each tier, and those views may be differently - that is, differently susceptible to persuasion. In the context of the nuclear power debate, this tiering of opinion has perverse implications. The first-tier risks of nuclear power are those associated with individual reactors, including the risks of accident or terrorist attack; the second-tier risks are those associated with mining, transport, processing, storage, and disposal of radioactive materials. Recent work asserts that despite entrenched public fear of nuclear power, it may be possible to induce people to support construction of low-emissions reactors as a strategy for mitigating climate change. But even if policymakers could employ the risk education strategies discussed in the literature to shift public opinion in favor of economic incentives for nuclear reactor development, there is no reason to think such strategies would be equally effective at changing attitudes toward second-tier risks and the command-and-control regulations necessary to address them. To the contrary, many people would likely continue to oppose certain types of government action on these latter problems, even assuming the complete success of the hypothesized first-tier education strategy. As a result, the United States could find itself with a thriving nuclear power sector, but without the political will to address the grave collateral risks. These observations lead to two conclusions, one related to the nuclear power example, and one to risk regulation more broadly. First, differently sticky public attitudes toward first- and second-tier nuclear risks and their regulatory solutions may defeat any effort to respond to climate change by significantly and safely increasing U.S. reliance on nuclear power. Second, efforts to change public risk perceptions may not advance a regulatory agenda, and may even prove counterproductive. Specifically, where multiple risk layers exist, a successful first-tier education effort and consequent policy changes could create or expose second-tier risks that defy regulatory solution, leaving policymakers stranded at the abrupt and unexpected end of a half-built bridge. Depending on the gravity of the second-tier risks, this regulatory dead end could be one that neither policymakers nor the public would have chosen ex ante.

Detection of Acetylcholine Receptor Blocking Antibodies by Flow Cytometry.

Detection of acetylcholine receptor (AChR) blocking antibodies through the use of a radiolabel has become standard procedure in most laboratories. Known drawbacks associated with radioassay, including cost of radioisotopes, hazards to laboratory professionals, and manufacture and disposal of radioactive materials, have prompted investigation into replacement assays. We describe here a high-throughput immunofluorescent flow cytometric assay designed for the detection of AChR blocking antibodies. In total, 323 serum samples were tested on both the AChR blocking radioassay and the new immunofluorescent flow cytometric assay. Analysis of the results revealed a 96.9% concordance between the two assay methods. Our results indicate that a new immunofluorescent flow cytometric AChR blocking antibody assay is not only feasible but clinically comparable in both sensitivity (91%) and specificity (99%) compared with radioassay.

Transport related sessions at American Society of Mechanical Engineers Pressure Vessel and Piping Conference, 23–27 July 2006, Vancouver, Canada

The ASME presents its Pressure Vessel and Piping Conference annually in North America. In 2006 this conference was officially titled 2006 Pressure Vessels & Piping Conference and the Eleventh International Conference on Pressure Vessel Technology and was held July 23rd–27th at the Hyatt Regency in Vancouver, British Columbia, Canada. The conference included over 700 technical papers, panel and plenary sessions, tutorials, and forums organised into more than 210 technical sessions. Technical papers presented at the conference were broken into tracks based on their content. Concurrent sessions at the conference lasted 105 min and three or four papers were typically presented during each session. At the conference, papers are presented in each of eight specific technical committee topic areas. One of these topic areas, the Operations, Applications, and Components (OAC) sponsors sessions in which papers are presented under several topic headings including Transportation, Storage, and Disposal of Radioactive Materials. In fact, the Transportation, Storage and Disposal of Radioactive Materials presentations represented over one-third of all OAC submissions at the 2006 conference. The nine Transportation, Storage and Disposal of Radioactive Materials sessions were organised by paper topic and included sessions on Introduction, Structural, Regulation of RAM Packaging and Transportation, Thermal (two sessions), Materials Technology, Materials for Long Term Storage, Regulatory Issues – Past and Present, and Glove Box Design Considerations. These sessions were organised primarily by Allan Smith of Savannah River National Laboratory (SRNL), with assistance from Nick Gupta, SRNL, and Matt Feldman, Oak Ridge National Laboratory (ORNL) and Oscar Shirani of Shaw Environmental and Infrastructure. The session titled Transportation, Storage and Disposal of Radioactive Materials – Introduction included four papers. The first paper was entitled Certification of SafeShield 2999A and was submitted by authors from Argonne National Lab (ANL), SRNL, and DOE-EM. This paper detailed a unique certification process in which SRNL acted as mediator between review team (DOE-EM and ANL) and the applicant. By using mediation, a path forward was found on a certification process that had stalled; resulting in the certification of the shipping package for its intended uses. The second paper was entitled Industry Commitment to Global Safety Standards and was presented by L. Green of the World Nuclear Transport Institute. This paper described some of industry’s experience of operating within the two-year regulatory review process and offered suggestions for improving this process. The third paper of the session was entitled Type B Package Radioactive Material

Structural study of trivalent lanthanide and actinide complexes formed upon solvent extraction

The coordination of the trivalent 4f ions, Ln = Nd3+, Eu3+ and Yb3+, as well as the trivalent 5f ion, Am3+, with diamide and dialkylphosphoric acid extractants, individually and in combination, was studied by use of X-ray absorption spectroscopy. These studies provide metrical information about the interatomic interactions between the f-ions (M3+) and the ligands, dihexylphosphoric acid (HDHP) and N,N'-dimethyl-N,N'-dioctylhexylethoxymalonamide (DMDOHEMA), that is of practical relevance to the control of metal-ligand binding in liquid-liquid extraction systems for the separation of trivalent actinide ions, An3+, from trivalent lanthanide ions, Ln3+. Through systematic variations of extraction conditions and extractant combinations, we have found that the HDHP complexes with M3+ involve MO6 coordination and distant M...P interactions, whereas the DMDOHEMA complexes with M3+ involve MO8 coordination. The combination of the EXAFS results with ancillary extraction data and IR results facilitates descriptions of the stoichiometries and structures of the molecular species formed in solution upon liquid-liquid extraction and leads to a new understanding of the binary extraction systems in terms of the strength and selectivity of An3+- vs. Ln3+-ligand interactions. This fundamental structure information affords insight into solvent extraction processes that are of contemporary and practical importance in heavy element chemistry and to environmentally related issues arising from the separation and disposal of radioactive materials, particularly actinides and selected fission products, in the field of nuclear waste reprocessing research.

An Inspector’s Perspective: Teamwork Between Licensees and Regulatory Agencies

The regulations governing the possession, use, storage, transportation, and disposal of radioactive material are too numerous and complicated to completely commit to memory or for a single person to fully understand. For this reason it is important for licensees and regulatory agencies to build a healthy, cooperative relationship to promote all aspects of radiation safety. A summary of regulatory goals and processes are presented from an inspector's perspective along with suggestions for entities working together to protect the health and safety of individuals and to protect the environment from potentially harmful effects of radiation.

Reduction in radioactive material use and waste generation at the National Institutes of Health.

The National Institutes of Health (NIH) has implemented an enhanced and comprehensive program to reduce the use of radioactive materials and to minimize the generation of radioactive and mixed wastes. The primary drivers for this program were increasing waste management costs, difficulties in disposing of certain types of radioactive wastes, particularly mixed wastes, and the increasing burden of managing radioactive materials in accordance with new regulatory requirements. These minimization efforts, coupled with the development of new on-site waste treatment options and the use of commercially available waste processing facilities, have resulted in significant reductions in the use of radioactive materials in bench research and the resultant amounts of radioactive and mixed waste generated and disposed off-site. A survey of users of radioactive materials was conducted to examine the reasons for this reduction and to predict future ordering trends. The primary factors contributing to reductions in ordering appear to be rapidly increasing use of non-radioactive research techniques, and increasingly burdensome safety and security regulations governing the use of radioactive material, which tend to discourage their use. The downward trends in use and disposal of radioactive materials at the NIH appear to be continuing.

Iothalamate measured by capillary electrophoresis is a suitable alternative to radiolabeled inulin in renal micropuncture

Inulin remains the gold standard for measurements of fluid reabsorption (Jv) and single nephron glomerular filtration rate (SNGFR) in micropuncture experiments. However, the method used to measure cold inulin in nanoliter samples is time-consuming, while the use of radiolabeled inulin is disadvantaged by possible radioactive contamination, disposal of radioactive material and cost of the isotope. It has been reported that non-radiolabeled iothalamate may be a suitable alternative for estimation of whole kidney GFR. The present study tested whether iothalamate can be used to measure Jv in microperfusion and free-flow micropuncture experiments. Superficial loops of Henle (LOH) were perfused from late proximal to early distal tubules with an end-like proximal solution. In the first set of experiments, the perfusate contained both iothalamate (1.9 mmol/L) and 3H-methoxy-inulin (50 microCi. mL(-1)). To test if iothalamate was able to detect changes in Jv, two additional sets of experiments were performed: (1) mannitol (61 mmol/L) was added to the perfusate to partially replace NaCl, a condition known to inhibit Jv; (2) LOH of remnant kidneys were perfused, which in previous experiments we showed to have a higher Jv. Lastly, free-flow micropuncture experiments were performed by infusing iothalamate IV at 18.3 mg. h(-1). Iothalamate analysis in nanoliter samples of renal tubular fluid obtained in vivo was performed by capillary electrophoresis (CE). In the first set of experiments, liquid scintillation counting of 3H-methoxy-inulin versus iothalamate analysis with CE resulted in almost identical calculated perfusion rates (20.4 +/- 0.6 vs. 20.6 +/- 0.7 nL. min(-1), N = 20) and tubular fluid/perfusate ratios (TF/P; 1.35 +/- 0.04 vs. 1.36 +/- 0.04) and thus also Jv (5.17 +/- 0.50 vs. 5.38 +/- 0.59 nL. min(-1)). In the mannitol experiments, iothalamate measurements showed that the addition of mannitol significantly reduced Jv from 4.98 +/- 0.40 (N = 19) to 0.72 +/- 0.58 nL. min(-1) (N = 33; P < 0.0001). Iothalamate determinations by CE were able to detect a significant increase in Jv in LOH of remnant rats perfused at 40 nL. min(-1)[from to 8.40 +/- 0.73 (N = 20) in sham-operated to 17.8 +/- 2.9 nL. min(-1) (N = 6) in remnant animals; P < 0.0001]. In free flow micropuncture experiments the ratio of tubular fluid to plasma iothalamate (TF/P) along the proximal tubule was 1.62 +/- 0.10 (N = 15). These data demonstrate that iothalamate can replace inulin to measure Jv in microperfusion and free-flow micropuncture experiments. Since iothalamate analysis by CE technique is a fast, easy and highly reproducible technique, it may become the gold standard method for the detection of fluid reabsorption in microperfused nephron segments.

Assessment of health risk levels associated with terrestrial gamma radiation dose rates in Nigeria

A decree on radiation safety and protection have been signed by the Federal Government of Nigeria that established a regulatory body to control the importation, application, transportation and disposal of radioactive materials in the environment. The fundamental function of the body is embodied on radiation protection of the country's population and the environment. However, the protection and assessment of any radiation pollution in the environment to a large extent is based on the knowledge of the baseline of radiation dose rate levels due to natural radionuclides. This study assesses the risks associated with terrestrial gamma radiation dose rate levels in some cities across the major geological formations of the country. Results showed that in the Northern region the number of individuals at risk of incurring cancer ranged between 0.25 and 3.25 yr −1 with an average value of 1.46±0.45, while in the southwestern region it ranged between 0.76 and 5.50 yr −1 with a mean value of 1.66±0.63 and in the southeastern region it was between 0.17 and 0.89 yr −1 with a mean value of 0.35±0.14. Assuming uniform exposure for the entire population of 98.5 million, it has been estimated that about 160 individuals annually are at risk of incurring cancer due to exposure to terrestrial gamma radiation.

A versatile enzyme immunoassay for the determination of progestogens in feces and serum

AbstractThe ability of zoos to monitor the reproductive status of their animals can vastly improve the effectiveness of husbandry/management practices, and noninvasive methods such as fecal steroid analysis are the easiest to apply in a zoo setting. Furthermore, enzyme immunoassay (EIA) is preferred to radioimmunoassay (RIA) as the method of quantifying hormones because EIAs do not involve the use, storage, and disposal of radioactive materials. However, progesterone is excreted in the feces as predominantly unconjugated metabolites (progestogens) and, until recently, antibodies able to cross‐react with a variety of progestogens were used primarily in RIAs. An EIA using a broad‐spectrum progestogen antibody is described and applied to serum and/or fecal samples from female African elephants, black rhinoceros, white rhinoceros, okapi, and hippopotami. The clear progestogen profiles generated in these species suggest that the described EIA would be as versatile as the RIA using the same antibody and could be a practical and economical alternative to RIAs for monitoring gonadal function via progestogen analysis in zoo species. Zoo Biol 20:227–236, 2001. © 2001 Wiley‐Liss, Inc.

Radiation safety of the sentinel lymph node technique in breast cancer.

Many publications attest to the potential of the sentinel lymph node technique in advancing the clinical management of melanoma and, more recently, breast cancer. Whilst not yet universally regarded as the standard of care, the technique is gaining wide acceptance. Use of a radiolabelled colloidal tracer is central to optimising sensitivity, and this brings with it the need to address radiation safety issues relating to the use of radioactive materials in the operating theatre and pathology laboratory, and the generation of radioactive waste. The radiation dose to the patient should also be determined if the professional is to reassure the patient by placing this in its proper context. For the purpose of this investigation, biodistribution data were obtained from patient studies to quantify the migration of tracer beyond the injection site, thereby permitting a detailed assessment of the internal dosimetry of the tracer and the resulting radiation dose to the patient. Uptake of tracer in the sentinel nodes, reticulo-endothelial system and circulating blood was investigated. The radiation dose to surgical staff was recorded using whole-body monitors and extremity dosimeters worn at the fingers. Clinical waste in the operating theatre was monitored and the radioactive content of significantly contaminated items determined. The radiation dose to pathology staff was estimated from knowledge of the radioactive content of the specimens obtained and a study of work practices. Migration of tracer was found to be minimal, with greater than 95% retention at the injection site. The effective dose resulting to the patient was 2.1x10(-2) mSv/MBq, with a mean breast dose of 7.2x10(-1) mGy/MBq. A mean whole-body dose of 0.34 microSv was received by surgical staff per procedure, with a mean finger dose of 0.09 mSv (90 microSv). Radiation doses received by pathology staff will be predominantly below measurable levels and are likely to be negligible unless primary specimens from a large number of studies are analysed promptly upon their excision. At operation, surgical swabs can become significantly contaminated and have been found to contain up to 22% of the administered activity, dependent upon the surgical procedure performed. It is concluded that moderate activities of technetium-99m labelled tracer are administered to the patient, and the radiation risk to the patient is consequently low relative to that from many other medical exposures. The radiation doses to staff groups involved in all aspects of the technique are low, and under normal circumstances and levels of workload, routine radiation monitoring will not be required. Standard biohazard precautions prevent direct intake of radioactive contamination. Radioactive waste is created in the operating theatre, and may be generated in the pathology laboratory if specimens are not routinely stored until fully decayed. This will require special handling if the disposal of radioactive material is not permitted.

Monte Carlo Approach to the Detectability of a Gamma Source Within a Scrap-Iron Truckload

Although the use and disposal of radioactive materials are regulated by appropriate national and international agencies, the possibility that such materials could enter the recycling process as scrap cannot be overlooked. Several incidents in recent years have demonstrated that given the many varied uses of radioactive materials in modern industry and medicine, it is possible for these materials to find a way into a scrap processor’s plant, where recycling may lead to internationally widespread contamination. This is a real problem that cannot be ignored.To the authors’ knowledge, this problem has been tackled primarily on an experimental basis. A Monte Carlo approach to the modeling of a detection system for scrap-iron-loaded trucks is presented. The crucial point is the representation of system inhomogeneities, which inevitably introduces elements of uncertainty and subjectivity. Correspondingly, the results obtained, while physically reasonable, are such that their substance resides in the general behavior of the curves and in the orders of magnitude.To estimate detectability limits for real situations, both homogeneous and inhomogeneous loads are considered for various positions of shielded and unshielded gamma sources. A sensitivity analysis of the assumptions of the model has shown satisfactory results.

Undisclosed Radioactivity in Specimens: How Much of a Problem?

Our institution, a clinical reference laboratory, receives specimens from a wide geographic location. In September 1996, a waste-disposal contractor alerted us to the presence of residual radioactivity in a 30-gallon (∼135-L) drum of what was supposed to be nonradioactive laboratory waste. Because clinical laboratories are regulated regarding the receipt, use, and disposal of radioactive material, we sought the source. Investigation revealed that the radiation originated from a urine specimen container, specifically from a specimen sent for catecholamine testing. During an evaluation for a possible pheochromocytoma, the patient involved had undergone nuclear imaging with radiolabeled m -iodobenzyl guanidine (MIBG) before urine collection for biochemical studies (MIBG is often used in nuclear medicine to evaluate suspected pheochromocytomas (1)). The isotope involved was 131I, which has an 8-day half-life. …

Licensing in the italian regulatory system in the use of radioisotopes

The regulatory system in force in Italy concerning radioisotopes is based on two statutes dating back to 1962 and 1964; the latter is based on a 1962 Directive of European Community, of which Italy is a Member. European Directives of 1980, 1984, 1989, 1990 and 1992 will be enacted into Italian legislation by January 1st, 1996. In the statutes in force the basic rules are established governing the holding and use of, trading in and disposal of radioactive material. These activities are subject to notification and licensing. Notification and licensing are based on two tiered system: a local, regional or provincial level and a national one, depending on the intersection of a number of parameters. The role of the governmental organs, state agencies such as ANPA (National Agency for Environmental Protection), local administrative bodies, their competence and their powers are discussed with regard to notification and licensing.