Sealed Sources Research Articles

A smart self-regenerative lithium ion supercapacitor with a real-time safety monitor

Lithium ion capacitors (LICs) show great promise for electricity storage. However, cycle degradation and unbalanced electrode kinetics of LICs are troublesome. Meanwhile, safety has become a stringent requirement for lithium devices. Finding methods to tackle these problems is rather challenging. Here, we develop a smart lithium ion supercapacitor (SLIC) by implanting a lithium electrode into a two-electrode pouch cell. The proof-of-concept SLIC has three smart functions: (1) energy boosting: it supports an on-line electrochemical charge injection protocol that boosts the energy of symmetrical all-carbon supercapacitors. A SLIC with single-wall carbon nanotubes (SWCNTs) as both electrodes has a gravimetric energy 5 times higher than conventional supercapacitors using SWCNTs and excellent durability with no measurable degradation during 10,000 cycles; (2) safety monitoring: it allows real-time diagnosis of cell decay and warns of dangers by a built-in feedback mechanism; (3) self-regeneration: it enables regeneration of a degraded SLIC by a voltage modulator. From a practical point of view, this SLIC concept offers a general solution for extending the life of sealed power sources.

Reducing radiation risks to staff for patients with permanently implanted radioactive sources requiring unrelated surgery.

Permanent implant of sealed radioactive sources is an effective technique for treating cancer. Typically, the radioactive sources are implanted in and near the disease, depositing radiation absorbed dose locally over several months. There may be instances where these patients must undergo unrelated surgical procedures when the radioactive material remains active enough to pose risks. This work explores these risks, discusses strategies to mitigate those risks, and describes a case study for a permanent iodine‐125 (I‐125) prostate brachytherapy implant patient who developed colorectal cancer and required surgery six months after brachytherapy. The first consideration is identifying the radiological risk to the patient and staff before, during, and after the surgical procedure. The second is identifying the risk the surgical procedure may have on the efficacy of the brachytherapy implant. Finally, there are considerations for controlling the radioactive substances from a regulatory perspective. After these risks are defined, strategies to mitigate those risks are considered. We summarize this experience with some guidelines: If the surgical procedure is near (e.g., within 5–10 cm of) the implant; and, the surgical intervention may dislodge sources enough to compromise treatment or introduces radiation safety risks; and, the radioactivity has not sufficiently decayed to background levels; and, the surgery cannot be postponed, then a detailed analysis of risk is advised.PACS numbers: 87.53Bn, 87.53Jw, 87.55.N, 87.56.bg

A New Storage Facility for Institutional Radioactive Wastes at IPEN.

IPEN, the Nuclear and Energy Research Institute in Sao Paulo, Brazil, has been managing the radioactive wastes generated in its own activities of research and radioisotope production as well as those received from many radioisotope users in the country since its start up in 1958. Final disposal options are presently unavailable for the wastes that cannot be managed by release after decay. Treated and untreated wastes including disused sealed radioactive sources and solid and liquid wastes containing radionuclides of the uranium and thorium series or fission and activation products are among the categories that are under safe and secure storage. This paper discusses the aspects considered in the design and describes the startup of a new storage facility for these wastes.

Assessment of the neutron emission anisotropy factor of a sealed AmBe source by means of measurements and Monte Carlo simulations

The neutron emission anisotropy factor of a sealed Americium–Beryllium source is experimentally determined and compared to Monte Carlo simulations. The measurements were done at the Italian Institute for Metrology of Ionizing Radiations using a long counter neutron detector and a “X.3” type AmBe sealed neutron source. Experimental data are compared to simulations performed with the MCNP code where the precise structure of the source is taken into account starting from its technical design. The contributions of the single structural parts are described to point out the effective sources of the emission anisotropy.

Radiological protection, safety and security issues in the industrial and medical applications of radiation sources

Abstract The use of radiation sources, namely radioactive sealed or unsealed sources and particle accelerators and beams is ubiquitous in the industrial and medical applications of ionizing radiation. Besides radiological protection of the workers, members of the public and patients in routine situations, the use of radiation sources involves several aspects associated to the mitigation of radiological or nuclear accidents and associated emergency situations. On the other hand, during the last decade security issues became burning issues due to the potential malevolent uses of radioactive sources for the perpetration of terrorist acts using RDD (Radiological Dispersal Devices), RED (Radiation Exposure Devices) or IND (Improvised Nuclear Devices). A stringent set of international legally and non-legally binding instruments, regulations, conventions and treaties regulate nowadays the use of radioactive sources. In this paper, a review of the radiological protection issues associated to the use of radiation sources in the industrial and medical applications of ionizing radiation is performed. The associated radiation safety issues and the prevention and mitigation of incidents and accidents are discussed. A comprehensive discussion of the security issues associated to the global use of radiation sources for the aforementioned applications and the inherent radiation detection requirements will be presented. Scientific, technical, legal, ethical, socio-economic issues are put forward and discussed.

Safety and security management of disused sealed radioactive sources in Thailand

When sealed radioactive sources are no longer in use, they should be returned back to the country of origin. However, most of them could not be returned to the origin; therefore, disused sealed radioactive sources (DSRS) have to be managed locally to ensure the safety and the security for long term storage before final disposal. The Radioactive Waste Management Center, Thailand Institute of Nuclear Technology, is authorized to operate the treatment, conditioning and storage of DSRS in Thailand. This paper will describe the operational procedures on characterization technique, identifation of unknown sources, volume reduction technique, re-packaging, registration and record keeping of DSRS. The successful results included that the record keeping of DSRS has been developed, and the national inventory of stored DSRS has been made up to date. The results confirmed that the quality control at the DSRS storage facility at Thailand Institute of Nuclear Technology was established and well implemented to ensure safe and secure management.

Brachytherapy in pelvic malignancies: a review for radiologists.

Brachytherapy, also known as sealed source or internal radiation therapy, involves placement of a radioactive source immediately adjacent to or within tumor, thus enabling delivery of a localized high dose of radiation. Compared with external beam radiation which must first pass through non-target tissues, brachytherapy results in less radiation dose to normal tissues. In the past decade, brachytherapy use has markedly increased, thus radiologists are encountering brachytherapy devices and their associated post-treatment changes to increasing degree. This review will present a variety of brachytherapy devices that radiologists may encounter during diagnostic pelvic imaging with a focus on prostate and gynecologic malignancies. The reader will become familiar with the function, correct position, and potential complications of brachytherapy devices in an effort to improve diagnostic reporting and communication with clinicians.

Application of the Hilbert Transform to measurements of liquid–gas flow using gamma ray densitometry

Measuring parameters of two-phase flows usually requires contactless measuring techniques to be used together alongside advanced methods of signal processing. One of these techniques, which has been employed for many years in measurements of liquid–gas, liquid–solids and gas–solid flows is a method of gamma-ray densitometry. Frequently in such measurements mutually delayed stochastic signals are received from the scintillation detectors. For the analysis of such signals a well-known cross-correlation function (CCF) is used due to the random nature of the signals and the presence of disturbances.This paper applies the Hilbert Transform to the time delay estimation in measurements of two-phase flow performed by using gamma-ray absorption. It presents the selected results of study of the modified CCFHT cross-correlation method, in which a Hilbert Transform of one measured signal is used. The experiments have been carried out for two-phase water–air flow through a horizontal pipeline of 30mm inner diameter. A sealed 241Am gamma ray source of 59.5keV energy has been used in the experiments mentioned above, together with scintillation detectors based on NaI(Tl) crystals. Based on obtained values of time delay the mean velocity of gaseous phase transported by liquid was calculated. It is stated, that the CCFHT method provides better metrological properties than the classical CCF. In the presented experiments combined uncertainties of the gas phase average velocity did not exceed 3.1% for CCF and 0.05% for CCFHT.

Radiation safety of sealed radioactive sources.

Sealed radioactive sources are used in a wide variety of occupational settings and under differing regulatory/licensing structures. The definition of a sealed radioactive source varies between U.S. regulatory authorities and standard-setting organizations. Potential problems with sealed sources cover a range of risks and impacts. The loss of control of high activity sealed sources can result in very high or even fatal doses to members of the public who come in contact with them. Sources that are not adequately sealed and that fail can cause spread of contamination and potential intake of radioactive material. There is also the possibility that sealed sources may be (or threaten to be) used for terrorist purposes and disruptive opportunities. Until fairly recently, generally licensed sealed sources and devices received little, if any, regulatory oversight and were often forgotten, lost or unaccounted for. Nonetheless, generally licensed devices can contain fairly significant quantities of radioactive material, and there is some potential for exposure if a device is treated in a way for which it was never designed. Industrial radiographers use and handle high activity and/or high dose-rate sealed sources in the field with a high degree of independence and minimal regulatory oversight. Failure to follow operational procedures and properly handle radiography sources can and has resulted in serious injuries and death. Industrial radiographers have experienced a disproportionately large fraction of incidents that have resulted in unintended exposure to radiation. Sources do not have to contain significant quantities of radioactive material to cause problems in the event of their failure. A loss of integrity can cause the spread of contamination and potential exposure to workers and members of the public. The National Council on Radiation Protection and Measurements has previously provided recommendations on select aspects of sealed source programs. Future efforts to provide recommendations for sealed source programs are discussed.

The search for an underground nuclear test

In a month-long exercise, the on-site inspection capabilities of the Comprehensive Nuclear-Test-Ban Treaty Organization were put to the test.

Factors affecting the repeatability of gamma camera calibration for quantitative imaging applications using a sealed source

Several applications in nuclear medicine require absolute activity quantification of single photon emission computed tomography images. Obtaining a repeatable calibration factor that converts voxel values to activity units is essential for these applications. Because source preparation and measurement of the source activity using a radionuclide activity meter are potential sources of variability, this work investigated instrumentation and acquisition factors affecting repeatability using planar acquisition of sealed sources. The calibration factor was calculated for different acquisition and geometry conditions to evaluate the effect of the source size, lateral position of the source in the camera field-of-view (FOV), source-to-camera distance (SCD), and variability over time using sealed Ba-133 sources. A small region of interest (ROI) based on the source dimensions and collimator resolution was investigated to decrease the background effect. A statistical analysis with a mixed-effects model was used to evaluate quantitatively the effect of each variable on the global calibration factor variability. A variation of 1 cm in the measurement of the SCD from the assumed distance of 17 cm led to a variation of 1–2% in the calibration factor measurement using a small disc source (0.4 cm diameter) and less than 1% with a larger rod source (2.9 cm diameter). The lateral position of the source in the FOV and the variability over time had small impacts on calibration factor variability. The residual error component was well estimated by Poisson noise. Repeatability of better than 1% in a calibration factor measurement using a planar acquisition of a sealed source can be reasonably achieved. The best reproducibility was obtained with the largest source with a count rate much higher than the average background in the ROI, and when the SCD was positioned within 5 mm of the desired position. In this case, calibration source variability was limited by the quantum noise.

Radioisotope method of compound flow analysis

The paper presents gamma radiation application to analysis of a multicomponent or multiphase flow. Such information as a selected component content in the mixture transported through pipe is crucial in many industrial or laboratory installations. Properly selected sealed radioactive source and collimators, deliver the photon beam, penetrating cross section of the flow. Detectors mounted at opposite to the source side of the pipe, allow recording of digital signals representing composition of the stream. In the present development of electronics, detectors and computer software, a significant progress in know-how of this field may be observed. The paper describes application of this method to optimization and control of hydrotransport of solid particles and propose monitoring facilitating prevent of a pipe clogging or dangerous oscillations.

Evidence-based integration of selective internal radiation therapy into hepatocellular carcinoma management.

The unique double irrigation of the liver (through the portal vein and the hepatic artery) and the predominantly arterial irrigation of liver tumors, particularly primary liver cancer, are the basis for the intra-arterial therapy of hepatocellular carcinoma (HCC). The most commonly used techniques are transarterial chemoembolization (TACE) with or without drug-eluting beads (DEBs) and transarterial radioembolization, which is also called selective internal radiation therapy (SIRT). TACE combines local drug delivery with concurrent tumor-feeding artery embolization. SIRT is a form of brachytherapy in which intra-arterially injected microspheres loaded with yttrium-90 serve as sealed sources for internal radiation purposes.

Velocity measurement of two-phase liquid-gas flow in a horizontal pipeline using gamma densitometry

This paper presents application of gamma-ray absorption method to liquid-gas flow investigation in a pipeline. In the described measurement two sealed 241Am radioactive sources and probes with NaI(Tl) scintillation crystals have been used. For the analysis of digital signals provided by detectors, a traditional cross-correlation function (CCF), and modified correlation methods based on the quotient of CCF and average magnitude difference function (AMDF), as well as the quotient of CCF, and average square difference function (ASDF) have been proposed. Exemplary results of the mean velocity determination of the gaseous phase transported by a liquid in the water-air mixture flow were demonstrated and the evaluation of its uncertainty have been presented.

Upgrading Existing Diffractometers with State-of-the-art Microfocus Sources

Modern microfocus X-ray sources define the state-of-the-art for a broad spectrum of applications in home laboratories, such as protein and small molecule crystallography, and small-angle scattering. These sources are combined with multilayer optics to image the source spot onto the sample. The optics provides a parallel or focused monochromatic X-ray beam, magnified to a suitable size. Low power sealed microfocus sources, such as Incoatec's IµS represent an attractive alternative to rotating anodes, with a significant reduction in cost and maintenance. Power loads of a few kW/mm2 in anode spot sizes below 50µm deliver a compact brilliant beam. For example, the IµSHighBrilliance delivers up to 1010 photons/s/mm2 in a spot size in the 100µm range. It is available for Cu, Mo, Ag, Cr and Co anodes. Since the launch in 2006 more than 400 IµS are now in operation worldwide for a large variety of applications in biology, chemistry, physics and material science. Are you tired of getting spare parts for an ancient rotating anode or is your detector performance only limited by your beam delivery system? We will demonstrate how to bring former high end diffractometers back to a superb performance for cutting edge science after an upgrade with an IµS source. Incoatec ensures full software and safety integration, and an installation hand in hand with the local service, providing a constant service support from your partners on site. In addition to all Bruker or Nonius systems, Incoatec also offers integrations into a wide range of instruments from Rigaku, Marresearch or STOE, also with Dectris or Huber components.

Poster — Thur Eve — 41: Considerations for Patients with Permanently Implant Radioactive Sources Requiring Unrelated Surgery

Permanent implant of sealed radioactive sources is an effective technique for treating cancer. Typically, the radioactive sources are implanted in and near the disease, depositing dose locally over several months. There may be instances where these patients must undergo unrelated surgical procedures when the radioactive material remains active enough to pose risks. This work explores these risks, discusses strategies to mitigate those risks, and describes a case study for a permanent I‐125 prostate brachytherapy implant patient who developed colo‐rectal cancer and required surgery 6 months after brachytherapy.The first consideration is identifying the risk from unwarranted radiation to the patient and staff before, during, and after the surgical procedure. The second is identifying the risk the surgical procedure may have on the efficacy of the brachytherapy implant. Finally, there are considerations for controlling for radioactive substances from a regulatory perspective. After these risks are defined, strategies to mitigate those risks are considered. These strategies may include applying the concepts of ALARA, the use of protective equipment and developing a best practice strategy with the operating room team.We summarize this experience with some guidelines: If the surgical procedure is near (ex: 5 cm) of the implant; and, the surgical intervention may dislodge radioisotopes enough to compromise treatment or introduces radiation safety risks; and, the radioisotope has not sufficiently decayed to background levels; and, the surgery cannot be postponed, then a detailed analysis of risk is advised.

Mass Production of Source Core for Iodine-125 Seed

Nowadays, brachytherapy using a sealed source called a ‘seed’ has drawn attention for the treatment of various cancers. Generally, Iodine-125 (I) has been used for the seed in the radiation therapy of eye disease and prostate cancer. I has a half-life of 59.4 days, and emits 27 keV and 31 keV X-rays, and a 35 keV γ-ray through an internal conversion process. An I seed of 4.5 mm (l) × 0.8 mm (O) has a structure composed of an inner source core and an outer shell capsule. I is adsorbed on the source core’s surface and a titanium capsule surrounds it. The seed is directly inserted into the human body to treat cancer cells, and the seed may be permanently left in tissues owing to the low activity and the excellent biocompatibility of Ti capsule (Fig. 1). The diverse materials and preparation of the source core have been reported for many years, for example, a palladium (Pd) coated silver wire, a silver (Ag) rod and a porous ceramic tube etc. The Korea Atomic Energy Research Institute (KAERI) previously used a bare ceramic rod and an Ag+Al2O3 rod 12 as the core. With regard to the preparation of an I seed, the electro deposition technique was used for adsorption of iodine on the silver surface. In addition, a chemical adsorption on the Pd coated silver wire, the impregnation into ceramics and iodine substitution after forming an intermediate having chloride (Cl) or bromide (Br) were reported. In our previous investigation, the effect of the various intermediates (N3 −, CO3 , C2O4 , AsO4 , Cl− and PO4 ) using each set of 10 Ag rods were reported. Among them, Ag rods modified using phosphate (PO4 ) showed the highest adsorption ability with the good substitution effect of iodine. On the basis of this technique, the studies on mass production using 100 Ag rods and leachability test of a finished source core prior to encapsulation were performed in this work. The uniformity of iodide adsorption on every silver rod in the same batch is important for mass production to reduce the number of abandoned rods. For this reason, we developed a cutting device (Fig. 2) precisely manufacturing the silver rods in 3 mm (l) and compared the iodide adsorption with the handmade rods. A silver wire of 0.5 mm (O) passes through a syringe needle (d) of 0.584 mm (O), and the wire is softened through the heating part (b). The length of this wire is adjusted with the help of micrometer (c) and can quickly cut to a uniform shape by using a steel blade (a). In the case of handmade rods, the wire was cut by using scissors, and both ends were manually polished with sandpaper.

Conditioning of disused Ra-226 radioactive sealed sources in Egypt

The present work describes the technical information on issues associated with the management of disused Ra-226 radioactive sources. The different settings needed to condition these sources in stainless steel capsules, working area setup, packaging preparation, Ra-226 source characterization, capsule welding, leakage test and data information are completely described. The radium sources addressed in the present work are mainly those which have been used in medicine and for industrial applications, in the form of sealed radiation sources. In Egypt hospitals are among the largest users of sealed radium radioactive sources which are mostly used for brachytherapy. The inventory of radium sources in large hospitals could be in the hundreds. There is a real risk that sources may be lost or mishandled, if very restricted procedures are not followed. An additional problem with these sources is that they are often leaking, due to internal overpressure. The small size of the sources, portability and high apparent value (due to the materials of encapsulation) increase the risk of theft.

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Mixing times and holdup of solids were measured in a gas–solid fluidized bed using radiotracer technique. Sand and air were used as solid and gas phase, respectively in the fluidized bed. Gold-198 labeled sand particles were used as radiotracer for mixing time measurement at different operating conditions and 137Cs sealed source was used for holdup measurement at different axial and radial positions. The experiments were conducted at different operating conditions. The measured mixing times ranged from 1.4 to 21 s at different conditions. It was observed that at a particular bed height, the mixing time initially decreases with increasing gas velocity and tend to become constant at higher gas velocities. However, mixing time increases with increasing bed height. The holdup fraction of solid was found to be more towards the wall compared to the centre of the column. The study provided inputs to improve the existing design, design of a new system and scale-up of the process.

Evidence for age-related performance degradation of 241Am foil sources commonly used in UK schools

The characteristics of alpha radiation have for decades been demonstrated in UK schools using small sealed 241Am sources. There is a small but steady number of schools who report a considerable reduction in the alpha count rate detected by an end-window GM detector compared with when the source was new. This cannot be explained by incorrect apparatus or set-up, foil surface contamination, or degradation of the GM detector. The University of Liverpool and CLEAPSS collaborated to research the cause of this performance degradation. The aim was to find what was causing the performance degradation and the ramifications for both the useful and safe service life of the sources. The research shows that these foil sources have greater energy straggling with a corresponding reduction in spectral peak energy. A likely cause for this increase in straggling is a significant diffusion of the metals over time. There was no evidence to suggest the foils have become unsafe, but precautionary checks should be made on old sources.