Radiation Protection

Out-of-field doses to untargeted organs may have long-term detrimental health effects for patients treated with radiotherapy. It has been observed that equivalent treatments delivered to patients with different accelerators may result in significant differences in the out-of-field dose. In this work, the points of leakage dose are identified about the gantry of several treatment units. The origin of the observed higher doses is investigated. LiF:Mg,Cu,P thermoluminescent dosimetry has been employed to quantify the dose at a several points around the linac head of various linear accelerators (linacs): a Varian 600C, Varian 21-iX, Siemens Primus and Elekta Synergy-II. Comparisons are also made between different energy modes, collimator rotations and field sizes. Significant differences in leaked photon doses were identified when comparing the various linac models. The isocentric-waveguide 600C generally exhibits the lowest leakage directed towards the patient. The Siemens and Elekta models generally produce a greater leakage than the Varian models. The leakage 'hotspots' are evident on the gantry section housing the waveguide on the 21-iX. For all machines, there are significant differences in the x and y directions. Larger field sizes result in a greater leakage at the interface plate. There is a greater leakage around the waveguide when operating in a low-energy mode, but a greater leakage for the high-energy mode at the linac face. Of the vendors investigated, the Varian 600C showed the lowest average leakage dose. The Varian 21-iX showed double the dose of the 600C. The Elekta Synergy-II had on average four times the dose leakage than the 600C, and the Siemens Primus showed an average of five times that of the 600C. All vendors show strong differences in the x and y directions. The results offer the potential for patient-positioning strategies, linac choice and shielding strategies to reduce the leakage dose to patients.

The x-ray leakage from the housing of a therapy x-ray source is regulated to be <0.1% of the useful beam exposure at 1 m from the source. It is to be expected that the machine leakage in the backward direction would be less because the gantry and stand contain significant amounts of additional metal to attenuate the x rays. A reduction in head leakage in this direction will have a direct effect on the thickness of the shielding wall behind the linear accelerator. However, no reports have been published to date on measurements in this area. The x-ray leakage in the backward direction has been measured from linacs having energies of 4, 6, 10, 15, and 18 MV using a 100 cm 3 ionization chamber and Al 2 O 3 dosimeters. The leakage was measured at nine different positions over the rear wall using a 3 ؋ 3 matrix with a 1-m separation between adjacent horizontal and vertical points with either the leftmost or rightmost column aligned with the target and isocenter. In general, the leakage is less than the canonical value, but the exact value depends on energy, gantry angle, and measurement position. There is significantly greater attenuation directly behind the gantry stand for all energies. Leakage at 10 MV for some positions exceeded 0.1%. Additionally, neutron leakage measurements were made for 10, 15, and 18 MV x-ray beams using track-etch detectors. The average neutron leakage was less than 0.1% except for 18 MV, where neutron leakage was more than 0.1% of the useful beam at some positions. Health Phys. 92(4):387-395; 2007

Co-Chair), Mayo Clinic. The meeting was designed to explore important areas of inquiry associated with use of ionizing radiation relevant to radiation protection, addressing frequently asked questions and concerns from both members of the public and radiation professionals. The meeting was organized into six sessions plus three honorary lectures and a special presentation. This paper summarizes the scientific content of the six sessions and is based on the notes of the co-chairs and the slides of the speakers. The three honorary lectures are included as other papers in this issue.

To provide dose-area-product (DAP) to effective dose (E) conversion factors for complete interventional procedures, based on in-the-field clinical measurements of DAP values and using tabulated E/DAP conversion factors for single projections available from the literature. Methods: Nine types of interventional procedures were performed on 84 patients with two angiographic systems. Different calibration curves (with and without patient table attenuation) were calculated for each DAP meter. Clinical and dosimetric parameters were recorded in-the-field for each projection and for all patients, and a conversion factor linking DAP and effective doses was derived for each complete procedure making use of published, Monte Carlo calculated conversion factors for single static projections. Results: Fluoroscopy time and DAP values for the lowest-dose procedure (biliary drainage) were approximately 3-fold and 13-fold lower, respectively, than those for the highest-dose examination (transjugular intrahepatic portosystemic shunt, TIPS). Median E/DAP conversion factors from 0.12 (abdominal percutaneous transluminal angioplasty) to 0.25 (Nephrostomy) mSvGy À1 cm À2 were obtained and good correlations between E and DAP were found for all procedures, with R 2 coefficients ranging from 0.80 (abdominal angiography) to 0.99 (biliary stent insertion, Nephrostomy and TIPS). The DAP values obtained in this study showed general consistency with the values provided in the literature and median E values ranged from 4.0 mSv (biliary drainage) to 49.6 mSv (TIPS). Conclusions: Values of E/DAP conversion factors were derived for each procedure from a comprehensive analysis of projection and dosimetric data: they could provide a good evaluation for the stochastic effects. These results can be obtained by means of a close cooperation between different interventional professionals involved in patient care and dose optimization.

The main features of the FLUKA Monte Carlo code, which can deal with transport and interaction of electromagnetic and hadronic particles, are summarised. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against experimental data. A short history of the code is provided and the following examples of applications are discussed in detail: prediction of calorimetric performances, atmospheric neutrino flux calculations, dosimetry in atmosphere and radiobiology applications, including hadrontherapy and space radiation protection. Finally a few lines are dedicated to the FLUKA server, from which the code can be downloaded.

We have developed a small animal conformal radiation therapy device that provides a degree of geometrical/anatomical targeting comparable to what is achievable in a commercial animal irradiator. small animal conformal radiation therapy device is capable of producing precise and accurate conformal delivery of radiation to target as well as for imaging small animals. The small animal conformal radiation therapy device uses an X-ray tube, a robotic animal position system, and a digital imager. The system is in a steel enclosure with adequate lead shielding following National Council on Radiation Protection and Measurements 49 guidelines and verified with Geiger-Mueller survey meter. The X-ray source is calibrated following AAPM TG-61 specifications and mounted at 101.6 cm from the floor, which is a primary barrier. The X-ray tube is mounted on a custom-made &quot;gantry&quot; and has a special collimating assembly system that allows field size between 0.5 mm and 20 cm at isocenter. Thr...

PURPOSE: To determine the relative dose rate distribution in water for the Bebig 20 mm and 30 mm skin applicators and report results in a form suitable for potential clinical use. Results for both skin applicators are also provided in the form of a hybrid Task Group 43 (TG-43) dosimetry technique. Furthermore, the radiation leakage around both skin applicators from the radiation protection point of view and the impact of the geometrical source position uncertainties are studied and reported. METHODS AND MATERIALS: Monte Carlo simulations were performed using the MCNP 6.1 general purpose code, which was benchmarked against published dosimetry data for the Bebig Ir2.A85-2 high-dose-rate iridium-192 source, as well as the dosimetry data for the two Elekta skin applicators. Both Bebig skin applicators were modeled, and the dose rate distributions in a water phantom were calculated. The dosimetric quantities derived according to a hybrid TG-43 dosimetry technique are provided with their corresponding uncertainty values. The air kerma rate in air was simulated in the vicinity of each skin applicator to assess the radiation leakage. RESULTS AND CONCLUSIONS: Results from the Monte Carlo simulations of both skin applicators are presented in the form of figures and relative dose rate tables, and additionally with the aid of the quantities defined in the hybrid TG-43 dosimetry technique and their corresponding uncertainty values. Their output factors, flatness, and penumbra values were found comparable to the Elekta skin applicators. The radiation shielding was evaluated to be adequate. The effect of potential uncertainties in source positioning on dosimetry should be investigated as part of applicator commissioning.

A methodological approach for a comparative assessment of ionising radiation effects on man and non-human species, based on the use of Radiation Impact Factor (RIF) -ratios of actual exposure doses to biota species and man to critical dose is described. As such doses, radiation safety standards limiting radiation exposure of man and doses at which radiobiological effects in non-human species were not observed after the Chernobyl accident, were employed. For the study area within the 30 km ChNPP zone dose burdens to 10 reference biota groups and the population (with and without evacuation) and the corresponding RIFs were calculated. It has been found that in 1986 (early period after the accident) the emergency radiation standards for man do not guarantee adequate protection of the environment, some species of which could be affected more than man. In 1991 RIFs for man were considerably (by factor of 20.0-1.1 ! 10 5 ) higher compared with those for selected non-human species. Thus, for the long term after the accident radiation safety standards for man are shown to ensure radiation safety for biota as well.

Key Points 1. CT radiation dose optimization is one of the major concerns for the scientific community. 2. CT image quality is dependent on the selected image reconstruction algorithm. 3. Iterative reconstruction algorithms have reemerged with the potential of radiation dose optimization by lowering image noise. 4. Tube current is the most common parameter used to reduce radiation dose along with iterative reconstruction. 5. Tube potential (kV) is also used for dose optimization with iterative reconstruction in CT angiography protocols and small patients.

A presença de vidros de urânio em colecções museológicas e privadas tem vindo a suscitar preocupações na área da protecção radiológica relativamente à possibilidade de exposição à radiação ionizante emitida por este tipo de objectos. Foram estudados catorze objectos de vidro com diferentes concentrações de óxido de urânio.

PHYSICAL REVIEW LETTERS 1 SEPTEMBER 196$ rate for different masses of the intermediate boson. The end point of the neutrino spectrum from the 184-in. cyclotron is-250 MeV, and neutrinos with this energy in collision with a stationary proton would produce a boson of mass equal to 2270m~. However, with the momentum distribution in the nucleus, higher boson masses may be attained, but only a small fraction of the protons can participate, so the rate of events falls off rapidly. Because of the low energy of the neutrinos produced at the 1S4-in. cyclotron, only a rather conservative limit of 2130m can be placed on the mass of the intermediate boson.

A study of the performance of five commercial radiotherapy treatment planning systems (TPSs) for common treatment sites regarding their ability to model heterogeneities and scattered photons has been performed. The comparison was based on CT information for prostate, head and neck, breast and lung cancer cases. The TPSs were installed locally at different institutions and commissioned for clinical use based on local procedures. For the evaluation, beam qualities as identical as possible were used: low energy (6 MV) and high energy (15 or 18 MV) x-rays. All relevant anatomical structures were outlined and simple treatment plans were set up. Images, structures and plans were exported, anonymized and distributed to the participating institutions using the DICOM protocol. The plans were then re-calculated locally and exported back for evaluation. The TPSs cover dose calculation techniques from correction-based equivalent path length algorithms to modelbased algorithms. These were divided into two groups based on how changes in electron transport are accounted for ((a) not considered and (b) considered). Increasing the complexity from the relatively homogeneous pelvic region to the very inhomogeneous lung region resulted in less accurate dose distributions. Improvements in the calculated dose have been shown when models consider volume scatter and changes in electron transport, especially when the extension of the irradiated volume was limited and when low densities were present in or adjacent to the fields. A Monte Carlo calculated algorithm input data set and a benchmark set for a virtual linear accelerator have been produced which have facilitated the analysis and interpretation of the results. The more sophisticated

Owing to ongoing technical refinements and intense scientific and clinical evaluations, computed tomography (CT) of the heart has left the research realm and matured into a clinical application that is about to fulfill its promise to replace invasive cardiac catheterization in selected patient populations. CT coronary angiography is technically more challenging than other CT applications owing to the nature of its target, the continuously moving heart. Rapid technical developments in this field require constant adaptation of acquisition protocols. These challenges, however, are in no way insurmountable for users with knowledge of the general CT technique. The intent of this communication is to provide those interested in and involved with coronary CT angiography with a step-by-step &quot;manual&quot; describing the authors&#39; approach to performing coronary CT angiography. Included are considerations regarding appropriate patient selection, patient medication, radiation protection...

This work compares the results of four different unfolding codes, MSANDB, MAXED, FRUIT and BONMA, which are based on different unfolding techniques. Additionally, Bayesian parameter estimation is also considered. All unfolding codes were supplied with the same set of input data acquired at the Environmental Research Station 'Schneefernerhaus' on the Zugspitze mountain, corresponding to continuous measurements of secondary neutrons from cosmic radiation. The HMGU high-energy extended Bonner sphere spectrometer (BSS), consisting of 16 measuring channels with 3 He proportional counters, was used as a reference BSS. The differences in the neutron spectra obtained with the different unfolding codes are discussed, and the uncertainties of integral quantities, like neutron fluence and ambient dose equivalent, are quantified.

One of the main studies that must be conducted before installing or building a radioisotopes production factory (RPF) is the radiological effect of the accidental releasing of the radioisotopes on the personnel and the environment surrounding the factory. The expected dose levels and the radioactive contamination areas must be determined to prepare the proper countermeasure after the hypothetical accident. In this study, the radioisotopes production factory is built inside a nuclear research center for production of 131 I and 99 Mo from irradiated low enrichment uranium (LEU) plates. It contains hot cells for extracting and preparing the 131 I and 99 Mo after irradiating the LEU plates inside the reactor core. The study focuses on evaluating the dose levels around the RPF after the accidental release of 131 I due to malfunction during the 131 I preparation process inside the iodine hot cell. Conservatively, the maximum amount of the 131 I release would be considered to calculate the maximum dose received by the personnel after the accident. The radiation dose levels around the RPF would be computed using GENII-2 code taking the site meteorological data into consideration. The results show that maximum dose would be located at distances from 800 to 5500 m from the RPF building at the direction ranging between 140 o and 200 o. The result shows that the maximum dose would be more than the permissible limit for the worker. The study ensures the importance of instant distributing the potassium iodide tablets to the persons who locate around the RPF building after the accident.

To assess the value of external shielding of the testis during pelvic radiotherapy. Nineteen patients, receiving radiotherapy to the pelvis with the lower border of the field at the obturator foramen, were randomly selected. A 5 half value layer cerrobent shield was positioned at the inferior border of the field. The dose to the testis was measured with and without the shield. Observations were made regarding the reflex cremaster contraction and phantom measurements were done at different distances from the perineum. The mean radiation dose to the testis for patients receiving treatment with no shield was 7.4cGy (1.3) and it was 5.7cGy (-/+2.5) for patients with external shield, this difference was statistically significant by the paired t test p&lt;0.0001. This accounted for a 22 % decrease in the dose received by the testis. The position of the testis with the contraction of the cremaster muscle and the dartos fascia after manipulation of the testis during diodes placement changed...

The proposition in the title of this paper is intended to draw a link between psychological processes involved in aesthetic gestural performance (e.g. music, dance) for both performers and perceivers. In the performance scenario, the player/dancer/etc., perceptually guides their actions, and acquires the skill for a performance through their previous perceptions. On the other side, the perceiver watching, listening to and experiencing another's motor performance, simulates the actions of the performance within the range of their own motor capabilities. These phenomena are possible due to common mechanisms of action and perception, and in tandem provide the basis for the rich experience of gestural performance.

Two severe accident scenarios are investigated in this paper as they have never been considered previously in the safety analysis report (SAR) of the Congo TRIGA Mark II research reactor (TRICO II) in Kinshasa, the Democratic Republic of Congo. The source term is derived from the reactor core after two postulated accidents: (1) a large plane crash with total destruction of the reactor building and (2) full damage of one fuel element while the reactor building remains intact. Total effective dose (TED), after core inventory, and dose profiles to human organs are derived to assess the operational safety of the reactor. Results from the study will be used to upgrade the current SAR of the reactor as the reactor safety and licensing concepts are changing over the years; the knowledge and lessons learned from the past experience are being updated accordingly with the available data. TEDs to workers of the facility show that higher values are obtained at areas near the source term at the time of the plane crash accident, which dies out as quickly as the plume is carried away following predominant meteorological conditions at the site. The situation with one fuel element totally damaged poses no threat as far as radiation protection is concerned and reveals a maximum TED of 1.30 × 10 −7 mSv at 100 m from the reactor core. This shows that the operation of this type of research reactor is reliable and safe.

Indoor radon (222 Rn) concentrations were measured in Paarl homes by means of electret ion chambers. The concentrations varied between 28 and 465 Bq m À3. The average values (Bq m À3) found in houses on the west and east side of the Berg River, which bisects Paarl, were 132 (711) and 37 (73), respectively. Radiometric analyses of soils show that the mean 226 Ra activity concentration is three times higher on the west than on the east side of the Berg River.

High-protection sunscreens have been suspected to prompt people to increase sun exposure, and thus to increase skin cancer risk. We tested the influence of both the actual protection (sun protection factor [SPF]) and the information about protection (label) on sun-exposure behavior. Design: Randomized controlled trial. Setting: Four French seaside resorts during summer 2001. Participants: A total of 367 healthy subjects during their 1-week holiday. Outcome was assessable in 98% of them. Intervention: Subjects were offered free sunscreens, with randomization into the following study arms: (1) SPF 40 labeled as "high protection"; (2) SPF 40 labeled as "basic protection"; and (3) SPF 12 labeled as "basic protection." Arm 4, ie, SPF 12 labeled as "high protection," was not implemented for ethical reasons. Subjects were not aware of the real target of the study and were blinded to the SPF value. Main Outcome Measure: Duration of sunbathing exposure during 1 week. Secondary outcomes were occurrence of sunburns and amount of sunscreen used. Influences of SPF and label were assessed separately. Results: Compared with the low-SPF group, the high-SPF group did not have longer sunbathing exposure (12.9±7.2 h/wk for high SPF vs 14.6±6.7 h/wk for low SPF; P=.06), experienced fewer sunburns (14% vs 24%; P=.049), and used less sunscreen (median, 30 g vs 109 g; PϽ.001). The label "high protection" or "basic protection" had no influence on these end points. Conclusions: In this adult population, higher SPF had no influence on duration of sun exposure and offered better protection against sunburns. Although higher SPF may increase sun exposure duration in specific populations, this effect cannot be viewed as a universal side effect of high-SPF sunscreens.

A semiempirical abrasion-ablation model has been successful in generating a large nuclear database for the study of high charge and energy (HZE) ion beams, radiation physics, and galactic cosmic ray shielding. The version reported herein has coulomb trajectory corrections, improved transmission factors, improved surface energy corrections, and light fragment emission was added. The cross sections that are generated are compared with measured HZE fragmentation data from various experimental groups. A research program for improvement of the database generator is discussed. Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

A wide variety of ' H compounds with different physico-chemical and radiotoxic properties are produced and used throughout the world. For the purpose of worker radiation safety, ' H compounds have been divided into five classes: oxide, gaseous, insoluble, soluble organic substances and precursors of nucleic acids. Based on recent radiobiological and dosimetnc data the quality factor for ' H has been suggested (QF = 2). Standards for oxide and gaseous 'H, reduced by a factor of 3-10, as compared with International Commission on Radiological Protection (ICRP) recommendations, have been suggested. New standards, 2-30 times lower than those for ' H oxide, have been worked out for the other three classes of ' H compounds. A limit for removable surface contamination from nonvolatile forms of ' H has been proposed (LSC = 1 kBq aW2).

Purpose: To assess long-term xerostomia in patients receiving parotid-sparing radiation therapy (RT) for head-and-neck cancer, and to find the patient and therapy-related factors that affect its severity. Patients and Methods: From March 1994 through January 2000, 84 patients received comprehensive bilateral neck RT using conformal and multisegmental intensity-modulated RT (IMRT) aiming to spare the major salivary glands. Before RT and periodically through 2 years after the completion of RT, salivary flow rates from each of the major salivary glands were selectively measured. At the same time intervals, each patient completed an 8-item self-reported xerostomia-specific questionnaire (XQ). To gain a relative measure of the effect of RT on the minor salivary glands, whose output could not be measured, the surfaces of the oral cavity (extending to include the surface of the base of tongue) were outlined in the planning CT scans. The mean doses to the new organ ("oral cavity") were recorded. Forty-eight patients receiving unilateral neck RT were similarly studied and served as a benchmark for comparison. Factors predicting the XQ scores were analyzed using a random-effects model. Results: The XQ was found to be reliable and valid in measuring patient-reported xerostomia. The spared salivary glands which had received moderate doses in the bilateral RT group recovered to their baseline salivary flow rates during the second year after RT, and the spared glands in the unilateral RT group, which had received very low doses, demonstrated increased salivary production beyond their pre-RT levels. The increase in the salivary flow rates during the second year after RT paralleled an improvement in xerostomia in both patient groups. The improvement in xerostomia was faster in the unilateral compared with the bilateral RT group, but the difference narrowed at 2 years. The major salivary gland flow rates had only a weak correlation with the xerostomia scores. Factors found to be independently associated with the xerostomia scores were the pre-RT baseline scores, the time since RT, and the mean doses to the major salivary glands (notably to the submandibular glands) and to the oral cavity. Conclusion: An improvement over time in xerostomia, occurring in tandem with rising salivary production from the spared major salivary glands, suggests a long-term clinical benefit from their sparing. The oral cavity mean dose, representing RT effect on the minor salivary glands, was found to be a significant, independent predictor of xerostomia. Thus, in addition to the major salivary glands, sparing the noninvolved oral cavity should be considered as a planning objective to further reduce xerostomia.

The use of a thallium-doped sodium-iodide well-type scintillation detector for the assay of the lowactivity radioisotope 40 K, in open-source potassium chloride aqueous solutions, is described. The hazards, safety concerns and radiowaste generation associated with using open-source radioactive isotopes can present significant difficulties, the use of hot cells and escalated costs in radioanalytical laboratory research. A solution to this is the use of low-hazard alternatives that mimic the migration and dispersion characteristics of notable fission products (in this case 137 Cs). The use of NaI(Tl) as a detection medium for naturally-abundant levels of 40 K in a range of media is widespread, but the use of 40 K as a radioactive tracer has not been reported. The use of such low-activity sources is often complicated by the ability to detect them efficiently. In this paper a scintillator detector designed to detect the naturally-abundant 40 K present in potassium chloride in tracer applications is described. Examples of the use of potassium chloride as a tracer are given in the context of ion exchange and electrochemical migration studies, and comparisons in performance are drawn from literature with hyper pure germanium semiconductor detectors, which are more commonly utilised detectors in high-resolution counting applications.

The USA Defence Threat Reduction Agency provided data in 2014 on the health status, including cancer, of the 4,843 sailors on the nuclear-powered United States Ship (USS) Ronald Reagan over the 2.55-year period from May 12th 2011 to Dec 31st 2013. Also provided were data on a matched control group of 65,269 US Navy personnel. Examination of the control population relative to the US national data gives a Relative Risk for all malignancies of RR=9.2 (95% CI 8.48<9.2<9.96). The result suggests a significant cancer risk associated with serving on a nuclear-powered ship, one which is not predicted by the science underlying current radiation protection legislation.

This chapter of the EMF Dosimetry Handbook provides guidance for assessing whether persons bearing metallic implants inside their bodies should be restricted from exposure to the upper tier limits of the radiofrequency (RF) safety guidelines (1998) published by the International Commission for Non-ionising Radiation Protection (ICNIRP) and the C95.1 (2005) standard of the Institute of Electrical and Electronic Engineers (IEEE). The recommendations presented here are based on original research by the authors, investigations of specific implant cases by the Telstra Research Laboratories in Melbourne, Australia and various publications in the scientific literature. Wherever possible, rules- of-thumb have been developed to provide simple and practical ways for assessing implants and for some external body worn metallic objects. Nonetheless, there remain some assessment scenarios that will still require detailed analysis.

OBJECTIVES: Transcatheter aortic valve implantation (TAVI) is a new method for the treatment of very high-risk patients with aortic valve stenosis. The radiation dose to which the patient and each member of the heart team are exposed during this new fluoroscopically guided intervention is unknown.

Interest in protection against solar ultraviolet radiation (UVR) among the general public in Australia has been increasing steadily as a result of the &#39;SunSmart&#39; campaigns run by the various state cancer councils. This increasing awareness is due in part to the requirements for occupational protection of outdoor workers and to provision of UVR protection for the recreational market. Behaviour outdoors can significantly affect exposure to solar UVR and use of items of personal protection can provide a substantial reduction in the UVR dose received. The protective properties of sunscreens, sunglasses, hats and clothing against UVR have been the subject of considerable research for some time, and over the last few years interest has extended to the provision of shade structures and the UVR protection provided by various commonly used materials. These materials include shadecloth, plastics, glass, windscreens and applicable tints. Australia has rigorous standards covering protec...

In situ gamma-ray spectrometry determines the quantities of radionuclides in some medium with a portable detector. The main limitation of in situ gamma-ray spectrometry lies in determining the depth distribution of radionuclides. This limitation is addressed by developing an improved in situ method for determining the depth distributions of gamma-ray emitting radionuclides in large area sources. This paper implements a unique collimator design with conventional radiation detection equipment. Cylindrically symmetric collimators were fabricated to allow only those gamma-rays emitted from a selected range of polar angles (measured off the detector axis) to be detected. Positioned with its axis normal to surface of the media, each collimator enables the detection of gamma-rays emitted from a different range of polar angles and preferential depths. Previous in situ methods require a priori knowledge of the depth distribution shape. However, the absolute method presented in this paper determines the depth distribution as a histogram and does not rely on such assumptions. Other advantages over previous in situ methods are that this method only requires a single gamma-ray emission, provides more detailed depth information, and offers a superior ability for characterizing complex depth distributions. Collimated spectrometer measurements of buried area sources demonstrated the ability of the method to yield accurate depth information. Based on the results of actual measurements, this method increases the potential of in situ gamma-ray spectrometry as an independent characterization tool in situations with unknown radionuclide depth distributions. #

Overhead, he heard the rumble of a plane on this hot August morning. This day had begun like many others for the young 27-year-old Tsutomu Yamaguchi, as he prepared to make the 300-km trip home, after a brief business trip. This day would be different, however, for his destiny would converge with that of a young man he did not know, 26year-old Thomas Ferebee. Five and a half hours earlier, Mr. Ferebee had embarked on his flight from Tinian, a small island in the northern Marianas to the city that Mr. Yamaguchi was visiting. Perhaps Mr. Yamaguchi saw the three planes 10,000 m above him. He did not see Mr. Ferebee, in one of those planes, pull a lever that would irrevocably initiate a chain of events that over the ensuing 43 seconds would forever change his life. They had different careers: Mr. Yamaguchi was an engineer 3 and Mr. Ferebee was the lead bombardier, over Hiroshima at 8:16 AM on August 6, 1945. Of the 350,000 people living there, 30% were instantly killed and another 30% were seriously injured. Another 50,000 people would die within the following few months. In terms of the effect on medical care, before the blast there were 200 doctors in Hiroshima, and 90% became acute casualties. Nurses fared even worse, with 1,654 (93%) of the 1,780 nurses killed or injured. Of 45 hospitals, only 3 were suitable at all for use to care for the injured. Mr. Yamaguchi was badly burned, yet a survivor. He stayed overnight in an air raid shelter and then began his 300-km trip home. After reaching his home, he returned to work immediately. 1 On that Wednesday morning at work it was overcast, until a few minutes before 11, when the clouds broke over his workplace. At 11:02 AM on August 9, 1945, it happened again, overhead, in his hometown of Nagasaki. Mr. Yamaguchi is the only known survivor documented to be within 3 km of ground zero for both events. Since 1957, as a registered survivor, he was granted a monthly allowance, free medical evaluation, and funeral costs. 1 There were 230,000 survivors of either Hiroshima or Nagasaki who did not die acutely, yet over the ensuing 55 years they had an increased incidence of cancer. Of those survivors, 120,000 were followed to assess quantitatively

Objectives This study assessed students’ awareness of radiation exposures and determined the impact a curriculum in clinical radiology (CICR) had on awareness. Methods Six hundred seventy medical students at one medical school were studied. CICR was delivered in yearly modules over the 5-year programme. Five hundred twenty-three students (years 1–5), exposed to increasing numbers of CICR modules and 147 students beginning medical school (year 0), represented the study and control groups, respectively. Students completed a multiple choice questionnaire assessing radiation knowledge and radiology teaching. Results Most students in the study population received CICR but 87% considered they had not received radiation protection instruction. The percentage of correctly answered questions was significantly higher in the study population than the control group (59.7% versus 38%, p &lt; 0.001). Students who received CICR achieved higher scores than those who did not (61.3% compared with 42....

The aim of this study was to assess knowledge of ionizing radiation exposure from diagnostic imaging examinations among emergency department (ED) providers. An electronic questionnaire was distributed to ED providers in a five-hospital university-affiliated health care system. Providers included attending emergency medicine (EM) physicians, EM residents, and midlevel providers (MLPs) (nurse practitioners and physicians assistants). Data were collected and analyzed. One hundred six of 210 providers (41 attending physicians, 32 residents, and 31 MLPs) completed the survey, for a response rate of 50.5%. More than two in five providers (44.6%) could not correctly identify which of six common imaging modalities used ionizing radiation. MLPs were more likely to incorrectly identify radiography (25%) and fluoroscopy (29%) as modalities that did not use ionizing radiation (P = .01 and P = .25 respectively). Fewer attending physicians (14.6%) than residents (37.5%) were not very comfortable ...

The primary purpose of obtaining laser targeting devices for C-arm fluoroscopy was to attempt to reduce radiation to the pediatric population in Connecticut Children&#39;s Medical Center&#39;s commitment to Imaging Gently. Fluoroscopy times for placing central lines in the operating rooms were documented for two months prior to the installation of the lasers and then for twenty procedures after installation and training on the devices. Fluoroscopy times trended down 25% calculated by a simple mean and standard deviation.

Background  Sentinel node radiolocalisation procedures are associated with low levels of radiation exposure. Radioactive material is present in the operating theatre and pathology laboratory. In most hospitals there are no official regulations in place for sentinel node radiation exposure. Aim  To establish guidelines on the safety of sentinel node mapping with emphasis on the management of radioisotopes. Methods  The current literature regarding sentinel

The objective of this manuscript is to provide a description of the International Commission for Radiation Protection (ICRP) model and a comparison to other models (the integrated exposure uptake biokinetic [IEUBKI and O'Flaherty models), including the software used with the models, and a comparison of the model predictions for selected situations. The ICRP biokinetic model for Pb is a multicompartmental model for Pb uptake and disposition in children and in adults. The model describes deposition and retention of absorbed Pb in numerous tissues, removal from tissues to plasma, and movement along various routes of excretion. Long-term skeletal behavior of Pb is described in terms of age-specific rates of restructuring of compact and trabecular bone. The ICRP model is more flexible and has wider applicability than the IEUBK model. The major disadvantages are that application of the computer model requires some basic computer skills, and the user must convert the Pb concentrations in food, air, soil, dust, paint, or other media to the amount of Pb ingested or inhaled per day. Direct comparisons between the ICRP model and the IEUBK model are provided by modeling blood Pb levels using the IEUBK vO.99d default Pb uptakes and intake values. The model is used to simulate occupational exposure cases and a controlled Pb inhalation experiment in adult humans. Finally, use of the model to explore situations with limited data is illustrated by simulating the kinetics and disposition of Pb during acute Pb poisoning and chelation therapy in a child.

ABSTRACT The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in our knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared with previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers, including space travelers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

The U.S. Department of Defense (USDOD) service members are at risk of exposure to ionizing radiation due to radiation accidents, terrorist attacks and national defense activities. The use of biodosimetry is a standard of care for the triage and treatment of radiation injuries. Resources and procedures need to be established to implement a multiple-parameter biodosimetry system coupled with expert medial guidance to provide an integrated radiation diagnostic system to meet USDOD requirements. Current USDOD biodosimetry capabilities were identified and recommendations to fill the identified gaps are provided. A USDOD Multi-parametric Biodosimetry Network, based on the expertise that resides at the Armed Forces Radiobiology Research Institute and the Naval Dosimetry Center, was designed. This network based on the use of multiple biodosimetry modalities would provide diagnostic and triage capabilities needed to meet USDOD requirements. These are not available with sufficient capacity el...

Due to the need for accurate neutron spectrum measurements in environments characterized by very high neutron and photon fluence rates, such as medical LINACs and the target area of particle accelerators, many research groups have adopted gold activation detectors inside Bonner sphere based instruments. Consequently, several response matrices have been derived. Nevertheless, the validation of such functions with reference neutron fields is still a difficult task, due to the limited availability of high fluence rate calibration facilities. An Italian collaboration, coordinated by the Radiation Protection Group of the Frascati National Laboratories, calculated the response matrix of a commercial BSS equipped with gold foils (0.1 mm height × 10 mm diameter) and performed a validation experiment with a 252 Cf source available at the ENEA-Bologna calibration laboratory. As a result, a spectrometric system with known accuracy is now available for workplace measurements. This work gives the details of the calculations, performed with MCNP, and shows the results of the validation experiment.