Radiation Dose Limits Research Articles

Theoretical study of tailings radioactive substances exemption standards-setting

A relationship between activity concentration of rare earth tailings naturally occurring radioactive material and equivalent tissue absorbed dose rate has been established from theory, according to it we calculated the conversion factor from unit activity concentration sample to absorbed dose rate of equivalent tissue. Then, considering the angular distribution of gamma rays flux which emitting from sample and combining with the result of effective thickness theoretical calculation with MCNP code, the geometric parameters of model that measures the radioactivity of tailings in-situ are obtained. According to a report that the limit of external gamma radiation dose is 0.3 mSv y-1 received per head from the naturally occurring radioactive material by International Atomic Energy Agency (IAEA), this value selected as control target and air absorded dose rate of several samples of different activity concentration was calculated under this standard, finally, the release limits of tailings was get, the sample could be released if air absorbed dose rate which not includes controbution of background is less than 55 nGy h-1 caused by it. We constructe an in-situ model according to the parameters deduced from theoretical calculation and make a experiment, part of the sample was taken to laboratory analysis, the result shows final date measured from the two methods are basic agreement, the relative error is 15.8%.

국내 원전 종사자의 방사선량 : 2009-2013

Although the perfomance indicators of the nuclear power plants in Korea show optimal, it requires detailed analysis and discussion centered on the radiation dose. As analysis methods, analysis on the radiation dose of nuclear power plants over the past five years was assessed by comparing the relevant radiation dose of radiation workers and per capita average annual radiation dose of the world's major nuclear power stations was also analyzed. The radiation workers over the annual radiation dose limit of 50 mSv were not. The contrast ratio of the radiation exposure according to the reactor type was the normal operation of PHWR was 6.2% higher than those of the PWR. This shows the radiation work of PHWR during normal driving operation is much more than those of PWR. According to the Performance Indicators of the World Association of Nuclear Operator, the annual radiation dose per unit in 2013 showed 527 man-mSv of Korea is the best country among the major nuclear power generating states, the world average was 725 man-mSv. The annual per capita radiation dose is about 80% less than 1 mSv of the public dose limit and also the average per capita dose showed a very low level as 0.82 mSv. Workers in related organizations showed 1.07 mSv, the non-destructive inspection agency workers showed 3.87 mSv. The remarkable results were due to radiation reduced program such as development of radiation shielding and radiation protection. In conclusion, the radiation exposured dose of nuclear power plants workers in Korea showed a trend which is ideally reduced. But more are expected to be difficul and the psychological insecurity against the operation of the nuclear power plants is existed to the residents near the nuclear power plants. So the radiation dose reduction policy and radiation dose follow up study of nuclear power plants will be continously excuted.

Strategy for stochastic dose-rate induced enhanced elimination of malignant tumour without dose escalation.

The efficacy of radiation therapy, a primary modality of cancer treatment, depends in general upon the total radiation dose administered to the tumour during the course of therapy. Nevertheless, the delivered radiation also irradiates normal tissues and dose escalation procedure often increases the elimination of normal tissue as well. In this article, we have developed theoretical frameworks under the premise of linear-quadratic-linear (LQL) model using stochastic differential equation and Jensen's inequality for exploring the possibility of attending to the two therapeutic performance objectives in contraposition-increasing the elimination of prostate tumour cells and enhancing the relative sparing of normal tissue in fractionated radiation therapy, within a prescribed limit of total radiation dose. Our study predicts that stochastic temporal modulation in radiation dose-rate appreciably enhances prostate tumour cell elimination, without needing dose escalation in radiation therapy. However, constant higher dose-rate can also enhance the elimination of tumour cells. In this context, we have shown that the sparing of normal tissue with stochastic dose-rate is considerably more than the sparing of normal tissue with the equivalent constant higher dose-rate. Further, by contrasting the stochastic dose-rate effects under LQL and linear-quadratic (LQ) models, we have also shown that the LQ model over-estimates stochastic dose-rate effect in tumour and under-estimates the stochastic dose-rate effect in normal tissue. Our study indicates the possibility of utilizing stochastic modulation of radiation dose-rate for designing enhanced radiation therapy protocol for cancer.

Computed tomography-related radiation exposure in children transferred to a Level I pediatric trauma center.

Pediatric trauma patients presenting to referring facilities (RF) often undergo computed tomography (CT) scans to identify injuries before transfer to a Level I pediatric trauma center (PTC). The purpose of our study was to evaluate RF compliance with the American College of Radiology (ACR) guidelines to minimize ionizing radiation exposure in pediatric trauma patients and to determine the frequency of additional or repeat CT imaging after transfer to a PTC. After institutional review board approval, a retrospective review of all pediatric trauma admissions from January 2010 to December 2011 at our American College of Surgeons Level I PTC was performed. Patient demographics, means of arrival, Injury Severity Score, and disposition were analyzed. Patients who underwent CT were grouped by means of arrival: those who were transferred from an RF versus those who presented primarily to the PTC. Compliance with ACR guidelines and need for additional or repeat CT scans were assessed for both groups. Six hundred ninety-seven children (aged <18 years) were identified, with a mean age of 10.6 years. Three hundred twenty-one (46%) patients presented primarily to the PTC. Three hundred seventy-six (54%) were transferred from an RF, of which 90 (24%) patients underwent CT imaging before transfer. CT radiation dosing information was available for 79 (88%) of 90 patients. After transfer, 8 (9%) of 90 of children imaged at an RF required additional CT scans. In comparison, 314 (98%) of 321 patients who presented primarily to the PTC and underwent CT received appropriate pediatric radiation dosing. Mean radiation dose at PTC was approximately half of that at RF for CT scans of the head, chest, and abdomen/pelvis (p < 0.01). Pediatric trauma patients transferred from RF often undergo CT scanning with higher than recommended radiation doses, potentially placing them at an increased carcinogenic risk. Fortunately, few RF patients required additional CT scans after PTC transfer. Finally, compliance with ACR radiation dose limit guidelines is better achieved at a PTC. Care management study, level IV.

SU‐E‐P‐10: Establishment of Local Diagnostic Reference Levels of Routine Exam in Computed Tomography

Introduction National diagnostic reference levels (NDRLs) can be used as a reference dose of radiological examination can provide radiation dose as the basis of patient dose optimization. Local diagnostic reference levels (LDRLs) by periodically view and check doses, more efficiency to improve the way of examination. Therefore, the important first step is establishing a diagnostic reference level. Computed Tomography in Taiwan had been built up the radiation dose limit value,in addition, many studies report shows that CT scan contributed most of the radiation dose in different medical. Therefore, this study was mainly to let everyone understand DRL's international status. For computed tomography in our hospital to establish diagnostic reference levels. Methods and Materials: There are two clinical CT scanners (a Toshiba Aquilion and a Siemens Sensation) were performed in this study. For CT examinations the basic recommended dosimetric quantity is the Computed Tomography Dose Index (CTDI). Each exam each different body part, we collect 10 patients at least. Carried out the routine examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined.Results:The majority of patients (75%) were between 60–70 Kg of body weight. There are 25 examinations in this study. Table 1 shows the LDRL of each CT routine examination.Conclusions:Therefore, this study would like to let everyone know DRL's international status, but also establishment of computed tomography of the local reference levels for our hospital, and providing radiation reference, as a basis for optimizing patient dose.

Preparation of the Operating Room

The history and general principles of OR design are discussed, including physical layout and design standards, which encompass the layout and storage of devices and equipment. As both patient and staff safety are paramount, all of the risks that can be mitigated by good design are discussed: biologic, ergonomic, chemical, and physical. Environmental issues in the OR are listed and include temperature, humidity, and lighting. The proper use, storage, and risks of electronic and mechanical devices are discussed. Infection control is addressed and includes hand hygiene, gloves and protective barriers, antimicrobial prophylaxis and nonpharmacologic preventive measures. A housekeeping section discusses the benefits of segregating clean, clean-contaminated, and dirty cases. OR scheduling is noted. Tables outline International Commission on Radiological Protection–recommended radiation dose limits; key principles of the Joint Commission Universal Protocol; devices used in the operating room; standard equipment for endovascular operating rooms; benefits of voice activation technology in the laparoscopic operating room; criteria for defining a surgical site infection; factors that contribute to the development of surgical site infection (SSI); Centers for Disease Control and Prevention hand hygiene guidelines; distribution of pathogens isolated from surgical site infections: operating room cleaning schedules; classification of operations in relation to the epidemiology of SSIs; and basic principles of OR efficiency. Figures depict patient positioning and basic components of an ultrasound transducer, This review contains 3 figures, 12 tables, and 214 references.

Preparation of the Operating Room

The history and general principles of OR design are discussed, including physical layout and design standards, which encompass the layout and storage of devices and equipment. As both patient and staff safety are paramount, all of the risks that can be mitigated by good design are discussed: biologic, ergonomic, chemical, and physical. Environmental issues in the OR are listed and include temperature, humidity, and lighting. The proper use, storage, and risks of electronic and mechanical devices are discussed. Infection control is addressed and includes hand hygiene, gloves and protective barriers, antimicrobial prophylaxis and nonpharmacologic preventive measures. A housekeeping section discusses the benefits of segregating clean, clean-contaminated, and dirty cases. OR scheduling is noted. Tables outline International Commission on Radiological Protection–recommended radiation dose limits; key principles of the Joint Commission Universal Protocol; devices used in the operating room; standard equipment for endovascular operating rooms; benefits of voice activation technology in the laparoscopic operating room; criteria for defining a surgical site infection; factors that contribute to the development of surgical site infection (SSI); Centers for Disease Control and Prevention hand hygiene guidelines; distribution of pathogens isolated from surgical site infections: operating room cleaning schedules; classification of operations in relation to the epidemiology of SSIs; and basic principles of OR efficiency. Figures depict patient positioning and basic components of an ultrasound transducer, This review contains 3 figures, 12 tables, and 214 references.

전리방사선 노출과 관리

Objectives: To investigate safety and health management, conditions in factories or facilities handling radiation-generating devices and radioactive isotopes were reviewed in terms of regulations of radiation safety control in Korea. Radiation exposure levels generated at those facilities were directly measured and evaluated for establishing an effective safety and health management plan. Methods: Government organizations with laws and systems of radiation safety and health were investigated and compared. There are three laws governing radiation-related employment such as occupational safety and health acts, nuclear safety acts, and medical service acts. We inspected 12 workplaces as research objects:four workplaces that manufacture and assemble semiconductor devices, three non-destructive inspection workplaces that perform inspections on radiation penetration, and five workplaces in textile and tire manufacturing. Monitoring of radiation exposure was performed through two methods. Spatial and surface monitoring using real-time radiation instruments was performed on each site handling radiation generating devices and radioactive isotopes in order to identify radiation leakage. Results: According to the occupational safety and health act, there is no legal obligation to measure ionizing radiation and set dose limits. This can cause confusion in the application of the laws, because the scopes and contents are different from each other. Surface dose rates in radiation generating devices such as implanters, thickness gages and accelerators, which were registered according to nuclear safety acts, using surveymeters, and seven of 36 facilities(19.4%) exceeded the international standards for surface radiation dose of <TEX>$10{\mu}Sv/hr$</TEX>. Conclusions: The results showed that occupational health and safety acts require a separate provision for measuring and assessing the radiation exposure of workers performing radiation work. Like noise, ionizing radiation will also periodically be controlled by including it in the object factors of work-environment measurement.

Ionizing radiation measurements and assay of corresponding dose rate around bottling and pharmaceutical facilities in Ilorin, Nigeria

Measurements of ionizing radiation and corresponding dose rate around bottling and pharmaceutical facilities in Ilorin, Nigeria, have been carried out using three duly calibrated Radalert Nuclear Radiation Meters and Global Positioning System. The survey meters were held at 1 m above the ground surface while obtaining readings at 31 locations within the study area. Measured radiation levels range from 1.14±0.09 to 2.48±0.13 mSv/yr with a mean of 1.60±0.26 mSv/ yr. The result shows that the exposure rates for all the stations are higher than the radiation dose limit of 1 mSv/yr for individual members of the public, while three stations are above the global average of 2.4 mSv/yr. It is recommended that areas with readings above global average be monitored closely to protect the public from adverse health effects.Keywords: Gamma radiation, Ionizing, Dose Rate, Ilorin, Nigeria

Review of NASA approach to space radiation risk assessments for Mars exploration.

Long duration space missions present unique radiation protection challenges due to the complexity of the space radiation environment, which includes high charge and energy particles and other highly ionizing radiation such as neutrons. Based on a recommendation by the National Council on Radiation Protection and Measurements, a 3% lifetime risk of exposure-induced death for cancer has been used as a basis for risk limitation by the National Aeronautics and Space Administration (NASA) for low-Earth orbit missions. NASA has developed a risk-based approach to radiation exposure limits that accounts for individual factors (age, gender, and smoking history) and assesses the uncertainties in risk estimates. New radiation quality factors with associated probability distribution functions to represent the quality factor's uncertainty have been developed based on track structure models and recent radiobiology data for high charge and energy particles. The current radiation dose limits are reviewed for spaceflight and the various qualitative and quantitative uncertainties that impact the risk of exposure-induced death estimates using the NASA Space Cancer Risk (NSCR) model. NSCR estimates of the number of "safe days" in deep space to be within exposure limits and risk estimates for a Mars exploration mission are described.

MATHEMATICAL MODELLING OF MECHANICAL BEHAVIOUR OF CELLULOSE-BASED FIBRES EXPOSED TO GAMMA RAYS AND HYDROTHERMAL TREATMENT

The deterioration of the natural polymers is a very complex process, and a problem that can be best addressed through modelling. The approach for modelling the rheological behaviour of different cellulose-based textile fibres (cotton, hemp, flax) when subjected to a hydrothermal treatment, followed by exposure to different doses of gamma-rays (5, 10, 15 and 25 kGy) is presented here. In order to predict the optimum radiation dose limit and hydrothermal aging time, the mathematical model was developed using MATLAB computational technique. To study the mechanical behaviour of the tested fibres, tensile tests were carried out using a TINIUS OLSEN dynamometer H5KT according to ISO 2062 norm. The model of correlation between the mechanical properties of the fibres and the independent variables was based on a polynomial second-degree equation, with the Least-Squares fitting approach that led to the coefficients of the mathematical model.

An experimental study of the scatter correction by using a beam-stop-array algorithm with digital breast tomosynthesis

Digital breast tomosynthesis (DBT) is a technique that was developed to overcome the limitations of conventional digital mammography by reconstructing slices through the breast from projections acquired at different angles. In developing and optimizing DBT, The x-ray scatter reduction technique remains a significant challenge due to projection geometry and radiation dose limitations. The most common approach to scatter reduction is a beam-stop-array (BSA) algorithm; however, this method raises concerns regarding the additional exposure involved in acquiring the scatter distribution. The compressed breast is roughly symmetric, and the scatter profiles from projections acquired at axially opposite angles are similar to mirror images. The purpose of this study was to apply the BSA algorithm with only two scans with a beam stop array, which estimates the scatter distribution with minimum additional exposure. The results of the scatter correction with angular interpolation were comparable to those of the scatter correction with all scatter distributions at each angle. The exposure increase was less than 13%. This study demonstrated the influence of the scatter correction obtained by using the BSA algorithm with minimum exposure, which indicates its potential for practical applications.

Safety considerations during transapical aortic valve implantation

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. Between April 2008 and August 2013, 1177 consecutive patients underwent transapical TAVI (TA-TAVI). In 22 consecutive patients undergoing TA-TAVI, the radiation doses to the cardiothoracic surgeon, cardiologist, anaesthesiologist (performing echocardiography examination), surgical assistant and nurse were measured. The radiation dose measurements were performed during TAVI using thermoluminescence and film dosimeters positioned on seven parts of the body: (i) chest above the lead apron, (ii) pelvic area below the apron, (iii) chest below the apron, (iv) thyroid gland above the apron, (v) near eyes, (vi) hands (using rings) and (vii) the feet. The results were compared with the values given in the international literature on recommended radiation dose limits for workers. The mean radiation time was 6.1 min and the mean dose-area product for the patients was 8.661 µGy · m(2). Analysis of the dosimeters and the calculation of the effective dose showed a per intervention dose of 0.03 mSv for the surgeon, 0.05 mSv for the assistant, 0.02 mSv for the cardiologist and the anaesthesiologist and 0.001 mSv for the nurse. The maximum ionizing radiation per intervention was 0.5 mSv at the right hand of the surgeon (holding the introducer sheet) and 0.7 mSv at the left hand of the surgical assistant. Additionally, the analysis of the body dose shows a maximum dose to the lower leg of the surgeon (0.3 mSv) and the genital area of the assistant (0.06 mSv). During a TA-TAVI procedure, the patients receive a higher X-ray dose than during coronary angiography with intervention. After 100 TAVI procedures, the members of the heart team sustain a comparable dose of ionizing radiation to the annual dose received by a busy interventional cardiologist. Therefore, maximal safety and optimal X-ray protection for patients and the members of the team are crucial and should be redefined.

In Vivo Imaging of Human Cholinergic Nerve Terminals with (–)-5-18F-Fluoroethoxybenzovesamicol: Biodistribution, Dosimetry, and Tracer Kinetic Analyses

(-)-5-(18)F-fluoroethoxybenzovesamicol ((18)F-FEOBV) is a vesamicol derivative that binds selectively to the vesicular acetylcholine transporter (VAChT) and has been used in preclinical studies to quantify presynaptic cholinergic nerve terminals. This study presents, to our knowledge, the first-in-human experience with (18)F-FEOBV, including radiation dosimetry, biodistribution, tolerability and safety in human subjects, and brain kinetics and methods for quantitative analysis of (18)F-FEOBV. Whole-body (18)F-FEOBV scans were obtained in 3 healthy human volunteers. Seven additional subjects underwent dynamic brain imaging 0-120, 150-180, and 210-240 min after bolus injection of (18)F-FEOBV. Arterial blood sampling was performed with chromatographic identification of authentic (18)F-FEOBV to determine the arterial plasma input function. Analysis methods included nonlinear least-squares fitting of a 2-tissue-compartmental model, reference tissue modeling, and late single-scan imaging. No pharmacologic or physiologic changes were observed after intravenous administration of up to 1.3 μg of (18)F-FEOBV. Radiation dosimetry estimates indicate that more than 400 MBq may be administered without exceeding regulatory radiation dose limits. Kinetic analysis showed brain uptake to be relatively high with single-pass extraction of 25%-35%. VAChT binding estimates varied by a factor of greater than 30 between the striatum and cortex. Coefficients of variation in k3 estimates varied from 15% to 30%. Volume of distribution measures yielded a dynamic range of approximately 15 but with little reduction in variability. Reference tissue approaches yielded more stable estimates of the distribution volume ratio (1 + BPND), with coefficients of variation ranging from 20% in the striatum to 6%-12% in cortical regions. The late static distribution of (18)F-FEOBV correlated highly with the distribution volume ratio estimates from reference tissue models (r = 0.993). (18)F-FEOBV PET confirms that the tracer binds to VAChT with the expected in vivo human brain distribution. Both reference tissue modeling and late static scanning approaches provide a robust index of VAChT binding.

Construction Shielding Design for Medical X-Ray Imaging Equipment

There are analytic methods for designing protective barriers however, they lack sufficient efficiency and considering the NCRP (National Council on Radiation Protection and measurements) reports, designing mechanical protective barrier in order to protect the initial x-ray radiation and absorption of the ray quality of such radiation is different. In this study, computer software was designed to calculate the needed barrier with high accuracy. For proper determination of thickness of the protective barrier, relevant information about curves of radiation weakness, dose limit and other items should be entered. This program was done in windows and designed in such a way that the operator works easily, flexibility of the program is acceptable and its accuracy and sensitivity is high. Meanwhile sometimes shielding is more than what required which lacks technical standards and cost effectiveness. When the application index is contrasting zero, thickness of NCRP49 calculation is about 20% less than the calculated rate done by the method of this study. The multi radiation sources in a single room are considered and non guaranteed radiation of NCRP hypothesis is removed. Difference between the theoretical and calculated rates of this method is X2 =10-5 which indicates accuracy and high efficiency of this software.

Safety case for transporting spent nuclear fuel

AbstractThe transportation safety case for transporting spent nuclear fuel is a requirement for licensing. It has both qualitative and semiquantitative aspects. The qualitative aspects include transportation regulations, radiation dose limits, role of the transportation package in transportation, transportation package certification process, training, emergency response, the performance of the transportation package in accidents and the evaluation of past transportation accidents. The quantitative aspects support the qualitative descriptions. Radiation doses accrued by members of the public and by workers are calculated using the code RADTRAN. Dose from both routine, incident free highway transportation and from highway transportation accidents are part of the safety case and will be compared with both background doses and the regulatory safety criteria. The radiation doses from routine transportation are calculated for the following: the maximally exposed member of the public, doses to vehicle escorts an...

Risco da exposição à radiaç ão ionizante durante procedimentos endovasculares

ObjectivesThe resource to endovascular procedures has become progressively more frequent and has increased concerns regarding the deleterious effects from radiation exposure. The purpose of this investigation is to evaluate and quantify scattered radiation exposure to which the patient and the surgical team are exposed, produced by a portable C-arm radioscopy unit during its use in the operating theatre. Material and methodsRadiation dose was measured in a controlled operating room with reproduction of usual conditions experienced during endovascular procedures in our operating theatre. A 15cm polimetilmetacrilate phantom was used as a geometrical simulation of the thorax. The scattered radiation was measured in several positions which were determined according to the usual distribution of the surgical and anesthesiological team in the room and at several heights. Radiation quantification was accomplished with resource to a portable radiation monitor RaySafe Xi Survey Detector, adjusting dose rate in mGy/s. Additionally, a RaySafe Xi R/F detector was used to measure the skin entrance exposure of the simulated patient. Readings were taken in pulsed fluoroscopy mode at a frequency of 4 frames per second (fps), digital subtraction mode and roadmap mode. The different magnifications available (Mag 1, 2 and 3) were also combined with each of these modes. In all situations, x-ray unit radiation dose was setted on level 3 which usually provides the best quality images with automatic real-time control of contrast and brightness. ResultsData analysis determined the distribution of scattered radiation among all elements of the surgical team. Maximum level of exposures was found at a height of 120cm in digital subtraction and roadmap modes. In this setting, surgical team scattered radiation exposure rates relative to patient skin entrance exposure rates were 0.47% for the surgeon, 0.21% for the anesthesiologist, 0.32% for the first assistant and 0.13% for the instrumenting nurse. The use of digital subtraction and roadmap increased levels of radiation exposure to patient and surgical team 5 times in comparison to pulsed fluoroscopy mode at 4fps. When personal radiation protection shielding was used, radiation levels were considerably inferior. ConclusionsProximity to the radiation x-ray tube increases significantly the amount of scattered radiation received. With the use of personal radiation shielding, the exposure is considerably lower and recommended radiation dose limits are not exceeded.

Assessment of Gamma Dose Rate at Mine Waste Dump

Abstract Exploitation of coal deposits in Upper Silesia is associated with production of large quantities of waste deposited at dumps. The tested samples from five dumps showed different radioactivity from each other. Radioactivity measurements made it possible to analyze the degree of risk with the factors specified by UNSCEAR such as radium equivalent activity Raeq, internal Ein and external Eex occupancy factor. There is a raised level of radiation in dumps as compared with outside dump areas. In the study area, however, there is no risk associated with elevated levels of radiation in relation to standards established by the Council of Ministers of the ionizing radiation dose limits.

Radiation-induced temporal lobe injury after intensity modulated radiotherapy in nasopharyngeal carcinoma patients: a dose-volume-outcome analysis

BackgroundTo identify the radiation volume effect and significant dosimetric parameters for temporal lobe injury (TLI) and determine the radiation dose tolerance of the temporal lobe (TL) in nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT).MethodsTwenty NPC patients with magnetic resonance imaging (MRI)-diagnosed unilateral TLI were reviewed. Dose-volume data was retrospectively analyzed.ResultsPaired samples t-tests showed all dosimetric parameters significantly correlated with TLI, except the TL volume (TLV) and V75 (the TLV that received ≥75 Gy, P = 0.73 and 0.22, respectively). Receiver operating characteristic (ROC) curves showed V10 and V20 (P = 0.552 and 0.11, respectively) were the only non-significant predictors from V10 to V70 for TLI. D0.5cc (dose to 0.5 ml of the TLV) was an independent predictor for TLI (P < 0.001) in multivariate analysis; the area under the ROC curve for D0.5cc was 0.843 (P < 0.001), and the cutoff point 69 Gy was deemed as the radiation dose limit. The distribution of high dose ‘hot spot’ regions and the location of TLI were consistent.ConclusionsA D0.5cc of 69 Gy may be the dose tolerance of the TL. The risk of TLI was highly dependent on high dose ‘hot spots’ in the TL; physicians should be cautious of such ‘hot spots’ in the TL during IMRT treatment plan optimization, review and approval.

Practice Policy and Quality Initiatives: Strategies for Optimizing Staff Safety in a Radiology Department

Employees in a radiology department are exposed to multiple risks, including injuries due to radiation exposure, poor ergonomics, or repetitive stress; those caused by wearing lead aprons or moving heavy equipment for portable studies; and needle sticks resulting in exposure to body fluids. Strategies to mitigate or prevent such risks include ergonomics initiatives for radiologists and technologists, appointment of a radiation safety officer to ensure compliance with radiation dose guidelines and policies, and use of equipment that prevents exposure to body fluids. In addition, there are regulations and guidelines from various government bodies on occupational radiation dose limits, handling of isotopes and chemotherapy agents, contact with patients with airborne infections, and needle stick injuries. A comprehensive staff safety program was developed for a clinical radiology department to provide a framework for staff injury prevention. The important parts of a staff safety program are observational safety audits and walkabouts and a safety reporting tool for employees. Faculty education about workplace environmental risks and their consequences, compliance with policies and guidelines on environmental safety, and development of a culture that encourages surveillance, reporting, and prompt action will go a long way toward improving overall safety for all workers in a radiology department.