RFPID: development and 3D-printing of a female physical phantom for whole-body counter.

Whole-body counters (WBC) are used in internal dosimetry forin vivomonitoring in radiation protection. The calibration processes of a WBC set-up include the measurement of a physical phantom filled with a certificate radioactive source that usually is referred to a standard set of individuals determined by the International Commission on Radiological Protection (ICRP). The aim of this study was to develop an anthropomorphic and anthropometric female physical phantom for the calibration of the WBC systems. The reference female computational phantom of the ICRP, now called RFPID (Reference Female Phantom for Internal Dosimetry) was printed using PLA filament and with an empty interior. The goal is to use the RFPID to reduce the uncertainties associated within vivomonitoring system. The images which generated the phantom were manipulated using ImageJ®, Amide®, GIMP®and the 3D Slicer®software. RFPID was split into several parts and printed using a 3D printer in order to print the whole-body phantom. The newly printed physical phantom RFPID was successfully fabricated, and it is suitable to mimic human tissue, anatomically similar to a human body i.e., size, shape, material composition, and density.

Actualización en equipos de Rayos X portátiles en odontología: revisión de literatura / Update on Hand-Held X-Ray Devices in Dentistry: a Literature Review

Resumen En las últimas dos décadas ha aumentado el uso de equipos portátiles de rayos X intraorales, los cuales son estabilizados por el operador. Si bien todos los equipos radiográficos presentan un riesgo inherente por el uso de radiación ionizante, el uso indebido de los equipos portátiles puede aumentar la exposición del operador. Se recomienda el uso de los equipos portátiles en un trípode o activados desde un área protegida. Sin embargo, en casos altamente justificados para su uso sin estos aditamentos, se debe seguir recomendaciones para disminuir la exposición del operador. Debido a que la radioprotección es fundamental al trabajar con rayos X, se debe favorecer el uso de equipos radiográficos dentales fijos sobre los equipos portátiles, ya que estos proporcionan una menor dosis de radiación al operador.

Abstract In the last two decades, the use of portable intraoral X-ray devices, stabilized by the operator, has increased. While all radiographic devices present an inherent risk from ionizing radiation, improper use of portable devices can increase operator exposure. Use of portable devices on a tripod or powered from a protected area is recommended. However, in highly justified cases, for using without these accessories, recommendations should be followed to reduce operator exposure. Because radioprotection is essential when using X-rays, fixed dental radiographic devices should be favored over portable equipment since the first provides a lower radiation dose to the operator.

Descripción de elementos de radioprotección y dosimetría en unidades de cardiología intervencionista sudamericanas: un estudio piloto / Radioprotection and dosimetry in Interventional cardiology units in South America. a pilot study

ANTECEDENTES: Las unidades de Cardiología intervencional han evidenciado un número creciente de procedimientos, cada vez más variados y complejos, lo cual podría eventualmente generar daños a los profesionales ocupacionalmente expuestos a radiaciones ionizantes (POEs) de no contar con los adecuados elementos de radioprotección y un uso correcto de ellos. OBJETIVO: Caracterizar la disponibilidad y utilización de los elementos de radioprotección y dosimetría de unidades de cardiología intervencionista de centros Sudamericanos. MATERIAL Y MÉTODOS: Se realizó una encuesta autoaplicada a 139 POEs, de ambos sexos de 7 países, a través de una plataforma on-line, se les consultó sobre características demográficas, dosimétricas y de radioprotección. RESULTADOS: Los elementos de radioprotección más tradicionales; delantales y cuellos plomados se utilizaron un 99,5 % y 98,4 % respectivamente, aquellos elementos más recientes como gafas, gorros y paños plomados solo alcanzaron un 36,8 %, 6,8 % y 34,2%, de utilización respectivamente, en cuanto a la utilización de los dosímetros, solo un 7,9 % lo hace apegado a las normas de la Organización Internacional de Energía Atómica (OIEA). CONCLUSIÓN: Se constató en la muestra analizada una falta de elementos de radioprotección y un uso inadecuado de ellos, urge realizar intervenciones educativas y técnicas para mejorar estos datos.

BACKGROUND: Due to the increasing number of interventional cardiology procedures currently performed, health professionals (POE) are exposed to ionizing radiation unless adequate protective elements are used. AIM: to describe the use of radioprotection elements and dosimetry in interventional cardiology laboratories in South America. METHODS: A self-administered survey was performed on 139 POE of both sexes and 7 countries using an online platform. Demographic data, dosimetry and characteristics of radioprotection analyzed. RESULTS: Commonly used radioprotective elements (lead aprons and collars) were used in 99.5% and 98% respectively. Recently introduced protection elements like lead goggles, caps and drapery were used in 36.8, 6.8 and 34.2% , respectively. Dosimetry according to the International Atomic Energy Commission (OIAE) was performed in only 7.9% of the procedures. CONCLUSION: there is a severe lack of adequate radioprotection during interventional cardiology procedures. Urgent measures, including technical implementation and educational interventions are needed to improve radioprotection in interventional cardiology.

PERFORMANCE OF THE INSTADOSETM DOSEMETER FOR INTERVENTIONAL RADIOLOGY AND CARDIOLOGY APPLICATION.

The aim of this article was to verify the performance of the Mirion InstadoseTM dosemeter under clinical conditions and to compare its response in typical X-ray fields used during interventional and cardiology procedures with the TLD-100, usually used for radiation dosimetry. It was also objective of this study to verify the feasibility of using the InstadoseTM dosemeter response at the chest level for estimation of occupational eye lens dose in cardiology and interventional radiology. Initially the response of the dosemeter was tested using continuous X-ray beams and the results showed that the Instadose dosemeter present a satisfactory behavior of the most important dosimetric properties based on the tests as described in the IEC 62387 standard. The measurements performed in clinical conditions showed that the InstadoseTM dosemeter response was comparable to that of TL dosemeters used in interventional radiology and cardiology procedures and there is a correlation between the eye lens doses and the chest doses measured with the InstadoseTM. Based on the results obtained, we recommend the use of the InstadoseTM dosemeter for purposes of occupational whole-body monitoring of medical staff in interventional radiology and cardiology procedures.

ALGORITHM BASED ON ARTIFICIAL BEE COLONY FOR UNFOLDING OF NEUTRON SPECTRA OBTAINED WITH BONNER SPHERES.

Occupational neutron fields usually have energies from the thermal range to some MeV and the characterization of the spectra is essential for estimation of the radioprotection quantities. Thus, the spectrum must be unfolded based on a limited number of measurements. This study implemented an algorithm based on the bee colonies behavior, named Artificial Bee Colony (ABC), where the intelligent behavior of the bees in search of food is reproduced to perform the unfolding of neutron spectra. The experimental measurements used Bonner spheres and 6LiI (Eu) detector, with irradiations using a thermal neutron flux and three reference fields: 241Am-Be, 252Cf and 252Cf (D2O). The ABC obtained good estimation of the expected spectrum even without previous information and its results were closer to expected spectra than those obtained by the SPUNIT algorithm.

Ergonomics in the Development and Prevention of Musculoskeletal Injury in Interventional Radiologists.

Interventional radiology is a constantly evolving specialty overlapping with multiple other specialties, including cardiology, vascular surgery, orthopedic surgery, urology, and minimally invasive surgery. Unique ergonomic considerations for interventional radiology include utilization of intraoperative viewing monitors and personal radiation protection equipment. Work-related injuries are common in interventional radiologists,1 often leading to pain while performing procedures or during time away from work. This review article aims to identify the ergonomic challenges related to interventional radiology and provide background, guidelines, and specific recommendations for prevention of musculoskeletal injury.

COMPARISON OF THE NEUTRON ENERGY RESPONSE OF TWO DIFFERENT TLD ALBEDO DOSEMETERS.

Albedo dosemeters remain the most used dosemeters in neutron individual monitoring. In Brazil, most of the neutron occupational fields are from radionuclide sources, often without any moderation, where albedo dosemeters have poor energy response. The purpose of this work is to compare the HP(10) energy response of the IRD and ALNOR TLD albedo dosemeter systems, calculated by their modelling with Monte Carlo code MCNPX. Their energy responses are similar, as expected, but the IRD system is about five times more sensitive than the ALNOR one. IRD albedo system can measure the Brazilian monthly recording level of 0.2 mSv, even for bare 252Cf and 241Am-Be neutron fields. On the other hand, the ALNOR system can measure values higher than 0.2 mSv only after huge moderation of theses sources. These results show that IRD TLD albedo is more suitable than the ALNOR one to measure low doses at occupational fields from radionuclide sources.

Building a resistance to ignition testing device for sunglasses and analysing data: a continuing study for sunglasses standards.

BACKGROUND: Sunglasses popularity skyrocketed since its advent. The ongoing trend led to the creation of standards to protect consumers from injuries and secondary hazards due to spectacles use. In Brazil, the corresponding standard is NBR ISO 12312-1:2015 and since there is no mandatory testing, evaluating sunglasses performance provides an insight into compliance with the standard. In a continuing revision of sunglasses standards requirements, resistance to ignition is one of the concerns, since sunglasses should be protected from burning into flames at a pre-determined temperature, which may protect user of getting their sunglasses into flames if some, cigarette sparks reaches the spectacles, as an example. This paper describes the building of a resistance to ignition system and the results of 410 samples that have been tested accordingly to ISO 12312-1. METHODS: The procedure is in accordance with the resistance to ignition test. It consists of heating a steel rod to 650 °C and pressing it against the sample surface for 5 s, with a force equivalent to the rod weight. For carrying out the assessments, we have build resistance to ignition testing system and assured the testing requirements of the standard. The apparatus has an electrical furnace with a temperature acquisition circuit and electronic control that maintains the temperature of the steel rod at 650 °C. A linear actuator was designed for the project to drive the steel rod vertically and pressing it against the sunglasses samples. The control system is composed by a Freescale development board FRDM-KL25Z with an ARM Cortex-M0 embedded. We have also provided a LabView PC interface for acquiring, displaying, and storing data as well as added a physical control panel to the equipment for performing the evaluations. We assessed 410 sunglasses frames at the built apparatus, where the 410 lenses came out to be in accordance with the guidelines provided by the ignition to resistance test. Out of the 410 tested frames, 50% were made of polyamide (nylon 12); 10% were made of polyamide (nylon 11, mamona oil); 5% were made of cellulose acetate; 15% were made of ABS and 20% were made of polycarbonate. Out of the 410 tested lenses, 80% were polycarbonate; 2% were polymethyl methacrylate (PMMA); 5% CR-39 (with polarizing filter inside); 12.8% polyamide; 0.2% glass. RESULTS: For all the 410 tested spectacles frames and lenses, none burst into flames or continued to melt at the end of the procedure, being in compliance with ISO 12312-1:2013. CONCLUSIONS: The evidences show that all the tested thermoplastic and thermosetting materials are exceptionally resistant to ignition and all samples assessed comply with the resistance to ignition test. The analysis of the sunglasses made herein assures that most of sunglasses currently available to population are made of safe material.

[Radiation protection provided by tungsten bismuth caps during interventional cardiology]. / ¿Es eficiente la protección anti-radiación otorgada por gorros de pabellón de tungsteno-bismuto en cardiología intervencionista?

BACKGROUND: The effectiveness against radiation of tungsten bismuth caps, used in interventional cardiology is not well known. AIM: To determine the degree of radiation protection conferred by these caps in real work conditions. MATERIAL AND METHODS: We compared the gross electric charges received at brain lobe levels by three occupationally exposed professionals who participated in 22 consecutive procedures, inside and outside of the tungsten bismuth cap. RESULTS: The median electric charges outside and inside the cap were 3.71 (range 1.46-5.62) and 2.2 (range 1.29-3.93) nC, which correspond to a 40% radiation attenuation. However, the protection was heterogeneous. CONCLUSIONS: Tungsten bismuth caps provide an adequate attenuation, but its degree is heterogeneous.

¿Es eficiente la protección anti-radiación otorgada por gorros de pabellón de tungsteno-bismuto en cardiología intervencionista? / Radiation protection provided by tungsten bismuth caps during interventional cardiology

Background: The effectiveness against radiation of tungsten bismuth caps, used in interventional cardiology is not well known. Aim: To determine the degree of radiation protection conferred by these caps in real work conditions. Material and Methods: We compared the gross electric charges received at brain lobe levels by three occupationally exposed professionals who participated in 22 consecutive procedures, inside and outside of the tungsten bismuth cap. Results: The median electric charges outside and inside the cap were 3.71 (range 1.46-5.62) and 2.2 (range 1.29-3.93) nC, which correspond to a 40% radiation attenuation. However, the protection was heterogeneous. Conclusions: Tungsten bismuth caps provide an adequate attenuation, but its degree is heterogeneous.

ENERGY AND ANGULAR DEPENDENCE OF RADIOPHOTOLUMINESCENT GLASS DOSEMETERS FOR EYE LENS DOSIMETRY.

Recent studies demonstrated that lens opacities can occur at lower radiation doses than previously accepted. In view of these studies, the International Commission of Radiological Protection recommended in 2011 to reduce the eye lens dose limit from 150 mSv/y to 20 mSv/y. This implies in the need of monitoring doses received by the eye lenses. In this study, small rod radiophotoluminescent glass dosemeters (GD-300 series; AGC, Japan) were characterized in terms of their energy (ISO 4037 X-rays narrow spectrum series, S-Cs and S-Co) and angular dependence (0  up to 90 degrees, with 2 ISO energies: N-60 and S-Cs). All acquisitions were performed at SCK•CEN-Belgium, using the ORAMED proposed cylindrical phantom. For selected energies (N-60, N-80, N-100, N-120 and N-250), the response of dosemeters irradiated on the ISO water slab phantom, at the Ruder Boskovic Institute-Croatia, was compared to those irradiated on the cylindrical phantom. GD-300 series showed good energy dependence, relative to S-Cs, on the cylindrical phantom. From 0 up to 45 degrees, the dosemeters showed no significant angular dependence, regardless whether they were tested when placed vertically or horizontally on the cylindrical phantom. However, at higher angles, some angular dependence was observed, mainly when the dosemeters were irradiated with low-energy photons (N-60). Results showed that GD-300 series have good properties related to Hp(3), although some improvements may be necessary.

Shielding Design for Adjacent, Underground Buildings of a Megavoltage Radiotherapy Facility.

In a radiotherapy facility, safety in areas next to the treatment room can be of concern when irradiating downward due to oblique x-ray transmission through the floor and/or walls, especially in areas immediately adjacent or underground. Even when there is no basement underneath, a usual conservative solution is to build a thick concrete slab as the base for the treatment room. Of course, this implies deeper soil excavation and higher associated costs. As a convenient alternative, the limiting walls can be buried a certain depth below floor level to shield oblique, downward irradiation. Besides, for space considerations, laminated barriers are usually employed, and some additional shielding to the floor may be required (L-shaped barriers). In this work, the author introduces an analytical method for calculating the required wall penetration below floor level or, alternatively, the additional floor shielding for L-shaped barriers, taking into account in either case the attenuation properties of the earth underneath the vault. Interestingly, the required penetration depth for a given wall barrier (primary or secondary), relative to a reference thickness, is only a function of basic attenuation data. Likewise, for a laminated, lead-concrete barrier, the required dimensions depend on the relative amount of lead used for the wall and on the corresponding attenuation data. The shielding design criteria developed in this work to protect underground nearby sites is conservative in nature, yet it yields optimal shield dimensions for wall footing and for wall-floor shielding, avoiding the need to construct oversized concrete slab floors.

MCNP SIMULATION OF THE HP(10) ENERGY RESPONSE OF A BRAZILIAN TLD ALBEDO NEUTRON INDIVIDUAL DOSEMETER, FROM THERMAL TO 20 MeV.

The Brazilian Instituto de Radioproteção e Dosimetria (IRD) runs a neutron individual monitoring system with a home-made TLD albedo dosemeter. It has already been characterised and calibrated in some reference fields. However, the complete energy response of this dosemeter is not known, and the calibration factors for all monitored workplace neutron fields are difficult to be obtained experimentally. Therefore, to overcome such difficulties, Monte Carlo simulations have been used. This paper describes the simulation of the HP(10) neutron response of the IRD TLD albedo dosemeter using the MCNPX transport code, for energies from thermal to 20 MeV. The validation of the MCNPX modelling is done comparing the simulated results with the experimental measurements for ISO standard neutron fields of (241)Am-Be, (252)Cf, (241)Am-B and (252)Cf(D2O) and also for (241)Am-Be source moderated with paraffin and silicone. Bare (252)Cf are used for normalisation.

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.

Efficacy of lead foil for reducing doses in the head and neck: a simulation study using digital intraoral systems.

OBJECTIVES: To assess the efficacy of lead foils in reducing the radiation dose received by different anatomical sites of the head and neck during periapical intraoral examinations performed with digital systems. METHODS: Images were acquired through four different manners: phosphor plate (PSP; VistaScan(®) system; Dürr Dental GmbH, Bissingen, Germany) alone, PSP plus lead foil, complementary metal oxide semiconductor (CMOS; DIGORA(®) Toto, Soredex(®), Tuusula, Finland) alone and CMOS plus lead foil. Radiation dose was measured after a full-mouth periapical series (14 radiographs) using the long-cone paralleling technique. Lithium fluoride (LiF 100) thermoluminescent dosemeters were placed in an anthropomorphic phantom at points corresponding to the tongue, thyroid, crystalline lenses, parotid glands and maxillary sinuses. RESULTS: Dosemeter readings demonstrated the efficacy of the addition of lead foil in the intraoral digital X-ray systems provided in reducing organ doses in the selected structures, approximately 32% in the PSP system and 59% in the CMOS system. CONCLUSIONS: The use of lead foils associated with digital X-ray sensors is an effective alternative for the protection of different anatomical sites of the head and neck during full-mouth periapical series acquisition.

Fetus absorbed dose evaluation in head and neck radiotherapy procedures of pregnant patients.

In this work the head and neck cancer treatment of a pregnant patient was experimentally simulated. A female anthropomorphic Alderson phantom was used and the absorbed dose to the fetus was evaluated protecting the patient's abdomen with a 7cm lead layer and using no abdomen shielding. The target volume dose was 50Gy. The fetus doses evaluated with and without the lead shielding were, respectively, 0.52±0.039 and 0.88±0.052cGy.

How are we protecting ourselves from radiation exposure? A nationwide survey.

PURPOSE: We performed a nationwide survey of Brazilian urologists to study behaviors toward radiation exposure and the use of protective and monitoring equipment. METHODS: A 13-question e-mail questionnaire was sent to 4,526 Brazilian urologists; the questions addressed demographic characteristics, radiation exposure, and the utilization of shielding devices and dosimeters. The reasons why these devices were not used were also investigated. RESULTS: A total of 332 completed questionnaires were analyzed (7.3 %); the median age of the respondents was 43.3 ± 10.8 years. Lead aprons and thyroid protection are utilized in every procedure by 84.4 and 53.89 % of respondents, respectively. Protective eyeglasses are never used by 72.12 % of the respondents. Older urologists were more likely not to use adequate protection. Of the urologists who responded, 76.42 % never use dosimeters. CONCLUSION: This study shows an unsatisfactory utilization of radiation-shielding devices and dosimeters, revealing a low compliance to the as low as reasonably achievable principle among Brazilian urologists.

Benefits of an intraoral stent in decreasing the irradiation dose to oral healthy tissue: dosimetric and clinical features.

OBJECTIVE: To determine whether an intraoral stent may decrease radiation dose to health tissues during intensity-modulated radiotherapy (IMRT) and to evaluate the effect on mucositis. STUDY DESIGN: A total of 33 patients with tongue or floor of the mouth cancer were retrospectively evaluated and divided into 2 groups: group 1 (with stent, n = 19) and group 2 (without stent, n = 14). Data were collected on dosimetric and mucositis outcomes. RESULTS: The mean dose to the maxilla was significantly lower in group 1 (20.9 Gy) than in group 2 (35.8 Gy) (P = .05). The mean dose to the ipsilateral parotid was 35.0 Gy in group 1 vs 41.8 Gy in group 2 (P = .05). No difference was seen in the severity of mucositis between groups (P = .82). However, grade III mucositis was present in group 1 at 4 weeks after IMRT, 1 week after its occurrence in group 2. CONCLUSIONS: A stent was effective in decreasing doses to healthy structures and delaying the emergence of mucositis.

Study of neutron scattering contribution on Hp(10) and H*(10) calibration in the Brazilian National Low Scattering Laboratory.

The neutron scattering at the Low Scattering Laboratory of the Brazilian National Neutron Laboratory has been studied using three different methods. The measurements have been done with a traceable standard (241)Am-Be from source-to-detector distances of 0.52-3.00 m. The obtained results with the variation distance methods are in agreement. Measurements with a large shadow cone are not worth for larger distances due to overshadowing. As the quantity required in a calibration is the response of the device being calibrated to the scattered neutron component in order to subtract this from the total response, for these purposes, the distance variation method must be used for each device. To quantify absolutely the scattering contribution on the quantity rates of fluence, Hp(10) and H*(10) in irradiation procedures, a Bonner sphere spectrometer with the shadow cone was employed. The evaluated scattering correction factor value may be employed for a distance of 1.00 m.