Patient dose measurement in common medical X-ray examinations and propose the first local dose reference levels to diagnostic radiology in Iran

Science.gov (United States)

Rasuli, Behrouz; Tabari Juybari, Raheleh; Forouzi, Meysam; Ghorbani, Mohammad

2017-09-01

Introduction: The main purpose of this study was to investigate patient dose in pelvic and abdomen x-ray examinations. This work also provided the LDRLs (local diagnostic reference levels) in Khuzestan region, southwest of Iran to help establish the NDRLs (national diagnostic reference levels). Methods: Patient doses were assessed from patient's anatomical data and exposure parameters based on the IAEA indirect dosimetry method. With regard to this method, exposure parameters such as tube output, kVp, mAs, FFD and patient anatomical data were used for calculating ESD (entrance skin dose) of patients. This study was conducted on 250 standard patients (50% men and 50% women) at eight high-patient-load imaging centers. Results: The results indicate that mean ESDs for the both pelvic and abdomen examinations were lower than the IAEA and EC reference levels, 2.3 and 3.7 mGy, respectively. Mean applied kVps were 67 and 70 and mean FFDs were 103 and 109, respectively. Tube loadings obtained in this study for pelvic examination were lower than all the corresponding values in the reviewed literature. Likewise, the average annual patient load across all hospitals were more than 37000 patients, i.e. more than 100 patients a day. Conclusions: The authors recommend that DRLs (diagnostic reference levels) obtained in this region, which are the first available data, can be used as local DRLs for pelvic and abdomen procedures. This work also provides that on-the-job training programs for staffs and close cross collaboration between physicists and physicians should be strongly considered.

The impact of diagnostic reference levels on patient doses from X-ray examinations

International Nuclear Information System (INIS)

Leitz, W.; Almen, A.

2008-01-01

The aim of this study was to evaluate the effect of diagnostic reference levels (DRL). For this study patient doses for the years 1999 and 2006 were available. Patient doses on a national level for eleven specified X-ray examinations were assessed. For the conventional examinations DRL have been used after the first survey in 1999, for computed tomography no DRL were used and for mammography DRL have been used for more than 20 years. Whereas the patient doses for conventional examinations were 30% lower in 2006 compared to 1999 the doses remained essentially the same for computed tomography and mammography. The widths of the dose distributions had only slightly decreased for conventional examinations and remained the same for computed tomography and mammography. This study has shown that after implementation of DRL a considerable dose reduction can be expected. Practices exceeding DRL will perform remedial actions with the aim to reduce dose, as demonstrated for the conventional examinations. Despite the fact that practices for computed tomography could compare doses with others practices, in the absence of DRL no actions to reduce doses were performed. The margin for further dose reductions in mammography is small due to the long term use of DRL. The impact of DRL on patient doses is changing with time. When introduced large dose reductions can be expected. After long term use DRL will counteract the introduction of new technique with unjustified high patient doses. Despite the merits in terms of dose saving it must be recognized that DRL has its limits - it has to be amended with other radiological protection activities. Other means and measures have to be developed, for example by the authorities, in order to ensure that optimisation is continued even when the patient doses are below the DRL. (author)

Patient doses in CT examinations in Switzerland: Implementation of national diagnostic reference levels

International Nuclear Information System (INIS)

Treier, R.; Aroua, A.; Verdun, F. R.; Samara, E.; Stuessi, A.; Trueb, P. R.

2010-01-01

Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerland. (authors)

Patient dose measurements in fluoroscopic examinations, aiming to the establishment of reference levels in Brazil

International Nuclear Information System (INIS)

Canevaro, L.; Drexler, G.

2001-01-01

This work was performed to investigate the actual exposure levels of the patients submitted to fluoroscopic procedures in diagnostic radiology. The data will be useful for a baseline in the establishment of local reference levels for fluoroscopic procedures, as recommended by the European Commission and IAEA. At present time there are no internationally accepted definitions for references levels for fluoroscopic complex procedures. Dose-area product (DAP) meters were employed in a pilot survey expressing the radiation exposures in terms of this quantity. This class of instrumentation has not yet been employed in Brazil. Parameters recorded were radiographic technique, fluoroscopy time, number of images, fluoroscopic and radiographic field sizes and DAPs. For fluoroscopy practice, a reference parameters set is recommended, instead of one diagnostic reference level. High patient exposures were found, calling for joined actions of health authorities, physicians, medical physicists, technicians and manufacturers. Monitoring of patient exposure, optimizing the radiation protection and establishing quantitative assessments of the exposition to the population in Brazil in this kind of procedure is important. (author)

Patient radiation doses and reference levels in pediatric interventional radiology

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Habib Geryes, Bouchra; Lachaux, Julie; Boddaert, Nathalie; Brunelle, Francis [Hopital Universitaire Necker Enfants Malades, Department of Paediatric Radiology, Paris (France); Bak, Adeline; Ozanne, Augustin; Saliou, Guillaume [Hopital Bicetre, Hopitaux Universitaires Paris-Sud, Department of Neuroradiology, Le Kremlin Bicetre (France); Naggara, Olivier [Hopital Universitaire Necker Enfants Malades, Department of Paediatric Radiology, Paris (France); Centre Hospitalier Sainte-Anne, Universite Paris Descartes Sorbonne Paris Cite, Centre de Psychiatrie et Neurosciences, INSERM S894, DHU Neurovasculaire, Paris (France); Centre Hospitalier Sainte-Anne, Department of Neuroradiology, Universite Paris Descartes, Sorbonne Paris Cite, INSERM UMR894, Paris (France)

2017-09-15

To describe, in a multicentric paediatric population, reference levels (RLs) for three interventional radiological procedures. From January 2012 to March 2015, children scheduled for an interventional radiological procedure in two French tertiary centres were retrospectively included and divided into four groups according to age: children younger than 2 years (A1), aged 2-7 years (A5), 8-12 years (A10) and 13-18 years (A15). Three procedures were identified: cerebral digital subtraction angiography (DSA), brain arteriovenous malformation (bAVM) embolization, and head and neck superficial vascular malformation (SVM) percutaneous sclerotherapy. Demographic and dosimetric data, including dose area product (DAP), were collected. 550 procedures were included. For DSA (162 procedures), the proposed RL values in DAP were 4, 18, 12 and 32 Gy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. For bAVM embolization (258 procedures), values were 33, 70, 105 and 88 Gy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. For SVM sclerotherapy (130 procedures), values were 350, 790, 490 and 248 mGy.cm{sup 2} in groups A1, A5, A10 and A15, respectively. Consecutive data were available to permit a proposal of reference levels for three major paediatric interventional radiology procedures. (orig.)

A comparison of the suitability of patient dosimetry methods for establishing diagnostic dose reference levels and optimisation strategies

International Nuclear Information System (INIS)

Gfirtner, Hans; Moores, B. Michael; Stieve, Friedrich E.

2008-01-01

For 50 adult patients referred for chest radiography, air kerma at the diaphragm KD, dose area product and entrance skin dose were measured. The air kerma at the diaphragm and the dose area product were determined using Diamentor M4KDK(PTW) which allows measuring air kerma and dose area product simultaneously. For the measurement of entrance skin dose TLDs are used. A 50% variation in dose, incident dose as well as entrance skin dose, was registered for the same patient thickness. The recommendation of ICRP to perform the measurements for DRLs at 'representative patients' and that of the CEC to use 'standard-sized patients' seem to make little sense in the case of chest radiography. It could be demonstrated, that the dose area product is the least appropriate dose quantity for patient measurements and to define dose reference levels. For some radiological examinations like chest, pelvis and lumbar spine the dose area product is even sex dependent. Incident dose and entrance surface dose are of equal quality for patient dose measurements in diagnostic radiography. (author)

Regional Diagnostic Reference Levels and Collective Effective Doses from Computed Tomography (CT) Scanners in India

International Nuclear Information System (INIS)

Livingstone, R.S.; Dinakaran, P.M.

2011-01-01

Diagnostic examinations performed using computed tomography (CT) are on the increase, and the use of this modality needs to be monitored periodically. The aim of this study was to formulate regional diagnostic reference levels (DRLs) and assess collective effective doses from CT scanners in Tamil Nadu, India. In-site CT dose measurements were performed for 127 CT scanners in Tamil Nadu as a part of the Atomic Energy Regulatory Board (AERB) funded project for a period of two years. Regional DRLs were formulated at third quartile level for three CT protocols such as thorax, abdomen and pelvis and were found to be 557 mGy.cm, 521 mGy.cm and 294 mGy.cm, respectively. The collective effective dose in Tamil Nadu was found to be 14.93 man Sv per day. (author)

Establishment of computed tomography reference dose levels in Onassis Cardiac Surgery Center

International Nuclear Information System (INIS)

Tsapaki, V.; Kyrozi, E.; Syrigou, T.; Mastorakou, I.; Kottou, S.

2001-01-01

The purpose of the study was to apply European Commission (EC) Reference Dose Levels (RDL) in Computed Tomography (CT) examinations at Onassis Cardiac Surgery Center (OCSC). These are weighted CT Dose Index (CTDI w ) for a single slice and Dose-Length Product (DLP) for a complete examination. During the period 1998-1999, the total number of CT examinations, every type of CT examination, patient related data and technical parameters of the examinations were recorded. The most frequent examinations were chosen for investigation which were the head, chest, abdomen and pelvis. CTDI measurements were performed and CTDI w and DLP were calculated. Third Quartile values of CTDI w were chosen to be 43mGy for head, 8mGy for chest, and 22mGy for abdomen and pelvis examinations. Third quartile values of DLP were chosen to be 740mGycm for head, 370mGycm for chest, 490mGycm for abdomen and 420mGycm for pelvis examination. Results confirm that OCSC follows successfully the proposed RDL for the head, chest, abdomen and pelvis examinations in terms of radiation dose. (author)

Estimating the population dose from nuclear medicine examinations towards establishing diagnostic reference levels

International Nuclear Information System (INIS)

Niksirat, Fatemeh; Monfared, Ali Shabestani; Deevband, Mohammad Reza; Amiri, Mehrangiz; Gholami, Amir

2016-01-01

This study conducted a review on nuclear medicine (NM) services in Mazandaran Province with a view to establish adult diagnostic reference levels (DRLs) and provide updated data on population radiation exposure resulting from diagnostic NM procedures. The data were collected from all centers in all cities of Mazandaran Province in the North of Iran from March 2014 to February 2015. The 75 th percentile of the distribution and the average administered activity (AAA) were calculated and the average effective dose per examination, collective effective dose to the population and annual effective dose per capita were estimated using dose conversion factors. The gathered data were analyzed via SPSS (version 18) software using descriptive statistics. Based on the data of this study, the collective effective dose was 95.628 manSv, leading to a mean effective dose of 0.03 mSv per capita. It was also observed that the myocardial perfusion was the most common procedure (50%). The 75 th percentile of the distribution of administered activity (AA) represents the DRL. The AAA and the 75 th percentile of the distribution of AA are slightly higher than DRL of most European countries. Myocardial perfusion is responsible for most of the collective effective dose and it is better to establish national DRLs for myocardial perfusion and review some DRL values through the participation of NM specialists in the future

Dose evaluation and establishment of reference levels in activity for nuclear medicine; Avaliação de dose e estabelecimento de níveis de referência em atividade para a medicina nuclear

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Ribeiro, Julio Cesar de Souza

2017-07-01

The International Commission on Radiation Protection (ICRP) has emphasized the importance of accurately determining the mean dose levels, or administered activity, received by the patients for each medical procedure that uses ionizing radiation. However, the number of bibliographic references addressing the need to know and optimize these levels is insufficient, or rather limited, which may lead to non-standardizes techniques, a lack of exposures control, and also the increase of associated radiological risks of these procedures. In this context, a software in Visual Basic® of Microsoft© language was developed whose function is to elaborate a method of obtaining the Reference Levels in Activity (RLA) for nuclear medicine patients by determining the third quartile of the examinations carried out. The program also allows obtaining absorbed dose values in critical organs based on patient specificities as age, sex and Body Mass Index (BMI) in order to evaluate the risk involved in each procedure. The main nuclear medicine diagnostic procedures were evaluated through the database of two public hospitals and a private clinic, obtaining the NRAs of each facility, where the software was validated by comparison with the traditionally accepted calculation methods. Due to the results obtained in each installation, in addition to NRA determination, gaps in treatment capacities and unjustified dose variations for the same procedure were identified, indicating the need for optimization. Thus, the developed program is able to provide the estimated values of effective and absorbed doses involved in each procedure, for each patient, providing reference values for nuclear medicine field, not available in the national scenario so far. (author)

Establishing diagnostic reference levels in digital radiology

International Nuclear Information System (INIS)

Bana, Remy Wilson

2016-04-01

Medical application of radiation has gained wider study since diagnostic radiology plays a very important role in modern medicine. The need of the service seems to increase since the invention of digital radiology as a new technology that promises greater accuracy while minimizing patient dose. However, it is not exempted in the harmonization of doses delivered to the patient undergoing same radiologic examination in different institutions either regional or nationwide. The objective of this project was to review the establishment of Diagnostic Reference Levels (DRLs) in digital radiology at National level with the aim to reduce patient dose while maintaining appropriate image quality. A general discussion on digital radiology has been presented focusing on the optimization of patient dose as well as dosimetric quantities used for the establishment of DRLs. Recommendations have been provided for Rwanda to initiate steps to establish National Diagnostic Reference Levels for common procedures in digital radiology. (au)

Fast in vivo volume dose reconstruction via reference dose perturbation

International Nuclear Information System (INIS)

Lu, Weiguo; Chen, Mingli; Mo, Xiaohu; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel

2014-01-01

Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

Patient dose audit of the most frequent radiographic examinations and the proposed local diagnostic reference levels in southwestern Nigeria: Imperative for dose optimisation

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N.N. Jibiri

2016-07-01

Full Text Available Diagnostic reference levels (DRLs is a veritable tool for dose optimisation and patient protection in diagnostic radiology. However, it is essential to have information on the local situation especially in a large hospital with several units or a cluster of healthcare centres within a geographical region with several X-ray units. In the present study, entrance surface doses (ESDs were measured in twelve (12 healthcare centres consisting of 15 radiological units using thermoluminescent dosimeters (TLDs. Seven radiological procedures such as; chest PA, abdomen AP, pelvis AP, lumbar spine AP, skull AP, knee AP, and hand AP frequently carried out in Nigeria were included in the study, and their local diagnostic reference levels (LDRLs were determined. The values of the determined LDRLs were compared with established NDRLs in UK, US, Slovenia, Italy and Brazil. The LDRLs determined in the two groups (healthcare centres studied ranged from 1.78 to 3.01, 2.71 to 2.84, 2.11 to 3.79, 3.93 to 8.79, 1.06 to 1.73 and 1.10 to 1.44 mGy for chest PA, pelvis AP, lumbar spine AP, skull AP, knee AP and hand AP respectively. Large variations were found among the X-ray units studied even within the same centre. Entrance surface doses obtained in pelvis AP and lumbar spine AP in both GROUP A and were found to be lower than the NRPB-HPA 2010 review for UK, while in all other five examinations, value of the measured entrance surface dose (ESD are higher than the doses reported in the UK review. The relative higher doses found in the study are attributable to higher tube load (mAs used and indicative of the need for dose optimisation in Nigerian radiological practice.

Developing patient-specific dose protocols for a CT scanner and exam using diagnostic reference levels

International Nuclear Information System (INIS)

Strauss, Keith J.

2014-01-01

The management of image quality and radiation dose during pediatric CT scanning is dependent on how well one manages the radiographic techniques as a function of the type of exam, type of CT scanner, and patient size. The CT scanner's display of expected CT dose index volume (CTDI vol ) after the projection scan provides the operator with a powerful tool prior to the patient scan to identify and manage appropriate CT techniques, provided the department has established appropriate diagnostic reference levels (DRLs). This paper provides a step-by-step process that allows the development of DRLs as a function of type of exam, of actual patient size and of the individual radiation output of each CT scanner in a department. Abdomen, pelvis, thorax and head scans are addressed. Patient sizes from newborns to large adults are discussed. The method addresses every CT scanner regardless of vendor, model or vintage. We cover adjustments to techniques to manage the impact of iterative reconstruction and provide a method to handle all available voltages other than 120 kV. This level of management of CT techniques is necessary to properly monitor radiation dose and image quality during pediatric CT scans. (orig.)

National reference doses for dental cephalometric radiography.

Science.gov (United States)

Holroyd, J R

2011-12-01

Diagnostic reference levels (DRLs) are an important tool in the optimisation of clinical radiography. Although national DRLs are provided for many diagnostic procedures including dental intra-oral radiography, there are currently no national DRLs set for cephalometric radiography. In the absence of formal national DRLs, the Health Protection Agency (HPA) has previously published National Reference Doses (NRDs) covering a wide range of diagnostic X-ray examinations. The aim of this study was to determine provisional NRDs for cephalometric radiography. Measurements made by the Dental X-ray Protection Service (DXPS) of the HPA, as part of the cephalometric X-ray equipment testing service provided to dentists and dental trade companies throughout the UK, were used to derive provisional NRDs. Dose-area product measurements were made on 42 X-ray sets. Third quartile dose-area product values for adult and child lateral cephalometric radiography were found to be 41 mGy cm² and 25 mGy cm², respectively, with individual measurements ranging from 3 mGy cm² to 108 mGy cm². This report proposes provisional NRDs of 40 mGy cm² and 25 mGy cm² for adult and child lateral cephalometric radiographs, respectively; these doses could be considered by employers when establishing their local DRLs.

Alanine dosimetry at NPL - the development of a mailed reference dosimetry service at radiotherapy dose levels

International Nuclear Information System (INIS)

Sharpe, P.H.G.; Sephton, J.P.

1999-01-01

In this paper we describe the work that has been carried out at National Physical Laboratory (NPL) to develop a mailed alanine reference dosimetry service for radiotherapy dose levels. The service is based on alanine/paraffin wax dosimeters produced at NPL. Using a data analysis technique based on spectrum fitting, it has been possible to achieve a precision of dose measurement better than ±0.05 Gy (1σ). A phantom set has been developed for use in high energy photon beams, which enables simultaneous irradiation of alanine dosimeters and ionisation chambers in a well defined geometry. Studies in photon beams of energies between 60 Co and 20 MeV have shown no significant energy dependence (<1%) for alanine relative to dose determination using a graphite calorimeter. Work is underway to extend the service to electron beams, and preliminary results are presented on the direct calibration of alanine in electron beams using a graphite calorimeter. (author)

Practical considerations in the development and application of reference levels

International Nuclear Information System (INIS)

Selby, J. M.; Kennedy, W. E. Jr.; Swinth, K. L.; Gilbert, R. O.; Soldat, J. K.

1988-05-01

Radiological exposures to the public during an accident that releases radioactive materials to the environment occur initially through the air pathway, secondly through a water pathway, and finally, through the food chain. From these exposure pathways, reference levels of radionuclides must be applied to limit public radiation doses. Such reference levels are difficult to develop and apply, particularly if the contaminants are transuranic elements such as plutonium. The reference level must be related to a resultant theoretical dose to the public through generic calculations. However, to permit rapid decisions after an accident, the reference levels need to be related to conditions or media in the environment that can be directly measured. They must also be tied to specific countermeasures such as sheltering, evacuation, or interdiction of drinking water or food supplies. This paper discusses the practical considerations in the development and application of reference levels for transuranic in the environment and the present capability to rapidly detect and quantify their concentrations following accidental contamination events. 16 refs., 3 tabs

Diagnostic reference levels for common computed tomography (CT) examinations: results from the first Nigerian nationwide dose survey.

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Ekpo, Ernest U; Adejoh, Thomas; Akwo, Judith D; Emeka, Owujekwe C; Modu, Ali A; Abba, Mohammed; Adesina, Kudirat A; Omiyi, David O; Chiegwu, Uche H

2018-01-29

To explore doses from common adult computed tomography (CT) examinations and propose national diagnostic reference levels (nDRLs) for Nigeria. This retrospective study was approved by the Nnamdi Azikiwe University and University Teaching Hospital Institutional Review Boards (IRB: NAUTH/CS/66/Vol8/84) and involved dose surveys of adult CT examinations across the six geographical regions of Nigeria and Abuja from January 2016 to August 2017. Dose data of adult head, chest and abdomen/pelvis CT examinations were extracted from patient folders. The median, 75th and 25th percentile CT dose index volume (CTDI vol ) and dose-length-product (DLP) were computed for each of these procedures. Effective doses (E) for these examinations were estimated using the k conversion factor as described in the ICRP publication 103 (E DLP  =  k × DLP ). The proposed 75th percentile CTDI vol for head, chest, and abdomen/pelvis are 61 mGy, 17 mGy, and 20 mGy, respectively. The corresponding DLPs are 1310 mGy.cm, 735 mGy.cm, and 1486 mGy.cm respectively. The effective doses were 2.75 mSv (head), 10.29 mSv (chest), and 22.29 mSv (abdomen/pelvis). Findings demonstrate wide dose variations within and across centres in Nigeria. The results also show CTDI vol comparable to international standards, but considerably higher DLP and effective doses.

Diagnostic reference levels in medical imaging

International Nuclear Information System (INIS)

Rosenstein, M.

2001-01-01

The paper proposes additional advice to national or local authorities and the clinical community on the application of diagnostic reference levels as a practical tool to manage radiation doses to patients in diagnostic radiology and nuclear medicine. A survey was made of the various approaches that have been taken by authoritative bodies to establish diagnostic reference levels for medical imaging tasks. There are a variety of ways to implement the idea of diagnostic reference levels, depending on the medical imaging task of interest, the national or local state of practice and the national or local preferences for technical implementation. The existing International Commission on Radiological Protection (ICRP) guidance is reviewed, the survey information is summarized, a set of unifying principles is espoused and a statement of additional advice that has been proposed to ICRP Committee 3 is presented. The proposed advice would meet a need for a unifying set of principles to provide a framework for diagnostic reference levels but would allow flexibility in their selection and use. While some illustrative examples are given, the proposed advice does not specify the specific quantities to be used, the numerical values to be set for the quantities or the technical details of how national or local authorities should implement diagnostic reference levels. (author)

Method of evaluation of diagnostics reference levels in computerized tomography

International Nuclear Information System (INIS)

Vega, Walter Flores

1999-04-01

Computerized tomography is a complex technique with several selectable exposition parameters delivering high doses to the patient. In this work it was developed a simple methodology to evaluate diagnostic reference levels in computerized tomography, using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Health Ministry. For evaluation of the MSAD, a dose distribution was obtained through a measured dose profile on the axial axis of a water phantom with thermoluminescence dosemeters, TLD-100, for different exam technique. The MSAD was evaluated hrough two distinct methods. First, it was evaluated by the integration of the dose profile of a single slice and, second, obtained by the integration on central slice of the profile of several slices. The latter is in of accordance with the ionization chamber method, suggesting to be the most practical method of dose evaluation to be applied in the diagnostic reference level assessment routine for CT, using TLDs. (author)

Referent 3D tumor model at cellular level in radionuclide therapy

International Nuclear Information System (INIS)

Spaic, R.; Ilic, R.D.; Petrovic, B.J.

2002-01-01

Aim Conventional internal dosimetry has a lot of limitations because of tumor dose nonuniformity. The best approach for absorbed dose at cellular level for different tumors in radionuclide therapy calculation is Monte Carlo method. The purpose of this study is to introduce referent tumor 3D model at cellular level for Monte Carlo simulation study in radionuclide therapy. Material and Methods The moment when tumor is detectable and when same therapy can start is time period in which referent 3D tumor model at cellular level was defined. In accordance with tumor growth rate at that moment he was a sphere with same radius (10 000 μm). In that tumor there are cells or cluster of cells, which are randomly distributed spheres. Distribution of cells/cluster of cells can be calculated from histology data but it was assumed that this distribution is normal with the same mean value and standard deviation (100±50 mm). Second parameter, which was selected to define referent tumor, is volume density of cells (30%). In this referent tumor there are no necroses. Stroma is defined as space between spheres with same concentration of materials as in spheres. Results: Referent tumor defined on this way have about 2,2 10 5 cells or cluster of cells random distributed. Using this referent 3D tumor model and for same concentration of radionuclides (1:100) and energy of beta emitters (1000 keV) which are homogeneously distributed in labeled cells absorbed dose for all cells was calculated. Simulations are done using FOTELP Monte Carlo code, which is modified for this purposes. Results of absorbed dose in cells are given in numerical values (1D distribution) and as the images (2D or 3D distributions). Conclusion Geometrical module for Monte Carlo simulation study can be standardized by introducing referent 3D tumor model at cellular level. This referent 3D tumor model gives most realistic presentation of different tumors at the moment of their detectability. Referent 3D tumor model at

Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values.

Science.gov (United States)

Ubeda, Carlos; Miranda, Patricia; Vano, Eliseo

2015-02-01

To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences in child size. These DRLs were obtained at the largest pediatric hospital in Chile, with an active optimization program, and could be used by other hospitals in the Latin America region to compare their current patient dose values and determine whether corrective action is appropriate. © 2015 American Association of Physicists in Medicine.

Reference levels for assays in opened installations of industrial radiography

International Nuclear Information System (INIS)

Leocadio, Joao C.; Tauhata, Luiz; Crispim, Verginia R.

2001-01-01

This work had as objectives to analyze the facilities open of industrial x-ray to obtain the distribution of doses in the operators and present proposed for the reference levels. The results of the monitoring revealed an improvement of the radiation protection conditions in the facilities and that the risk of potential exposure was reduced. The advantage of the proposed reference levels is that the supervisors would enlarge the frequency of audits in the facilities opened to accomplish the investigations and interventions.The facilities open with 'bunkers' presented distributions with 95% of the doses below 0,2 mSv and the distributions of the facilities with cordoned area they had 75% of the doses below 0,4 mSv. (author)

Establishment of institutional diagnostic reference level for computed tomography with automated dose-tracking software.

Science.gov (United States)

Liang, Chong R; Chen, Priscilla X H; Kapur, Jeevesh; Ong, Michael K L; Quek, Swee T; Kapur, Subhash C

2017-06-01

The aim of this study was to establish institutional diagnostic reference levels (DRLs) by summarising doses collected across the five computed tomography (CT) system in our institution. CT dose data of 15940 patients were collected retrospectively from May 2015 to October 2015 in five institutional scanners. The mean, 75th percentile and 90th percentile of the dose spread were calculated according to anatomic region. The common CT examinations such as head, chest, combined abdomen/pelvis (A/P), and combined chest/abdomen/pelvis (C/A/P) were reviewed. Distribution of CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED) were extracted from the data for single-phasic and multiphasic examinations. The institutional DRL for our CT units were established as mean (50th percentile) of CTDIvol (mGy), DLP (mGy.cm) and ED (mSv) for single and multiphasic studies using the dose-tracking software. In single phasic examination, Head: (49.0 mGy), (978.0 mGy.cm), (2.4 mSv) respectively; Chest: (6.0 mGy), (254.0 mGy.cm), (4.9 mSv) respectively; CT A/P (10.0 mGy), (514.0 mGy.cm), (8.9 mSv) respectively; CT C/A/P (10.0 mGy), (674.0 mGy.cm), (11.8 mSv) respectively. In multiphasic studies: Head (45.0 mGy), (1822.0 mGy.cm), (5.0 mSv) respectively; Chest (8.0 mGy), (577.0 mGy.cm), (10.0 mSv) respectively; CT A/P: (10.0 mGy), (1153.0 mGy.cm), (20.2 mSv) respectively; CT C/A/P: (11.0 mGy), (1090.0 mGy.cm), (19.2 mSv) respectively. The reported metrics offer a variety of information that institutions can use for quality improvement activities. The variations in dose between scanners suggest a large potential for optimisation of radiation dose. © 2017 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

The establishment of local diagnostic reference levels for paediatric interventional cardiology

International Nuclear Information System (INIS)

McFadden, S.; Hughes, C.; D'Helft, C.I.; McGee, A.; Rainford, L.; Brennan, P.C.; McCrum-Gardner, E.; Winder, R.J.

2013-01-01

Background: There is a paucity of information worldwide on radiation exposure in paediatric interventional cardiology. At present Nationally established Diagnostic Reference Levels exist for adult interventional cardiology procedures in the UK but little data is available for paediatrics. In addition, interventional cardiology has been identified as one the highest contributors to medical exposure to ionising radiation and children are more radiosensitive than adults. Objective: This study sought to determine current radiation dose levels in paediatric interventional cardiology (IC) with a view to establishing local diagnostic reference levels (LDRL). Methods: Radiation dose and examination details were recorded for 354 paediatric patients examined by IC in a specialised paediatric centre in Europe. Radiation doses were recorded using a Dose Area Product meter along with examination details. Procedures were categorised as either diagnostic (A) or therapeutic (B). Data was further sub-divided into five age ranges; (1) newborn <1 year (2) 1 <5 years (3) 5 <10 years (4) 10 <15 years (5) 15 years and over. Proposed LDRL were calculated from the mean dose area product readings. Results: The mean patient age was 2.6 years (range 0.0 days–16 years) and weight was 14.9 kg (range 2.4–112 kg). LDRL for the five age groupings were calculated as 190, 421, 582, 1289 and 1776 cGycm² respectively. Conclusion: Local dose reference levels have been proposed for paediatric IC and can be used as a benchmark for other hospitals to compare against their own radiation doses

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

International Nuclear Information System (INIS)

Yeh, M; Wang, Y; Weng, H

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Yeh, M; Wang, Y; Weng, H [Chiayi Chang Gung Memorial Hospital of The C.G.M.F, Puzi City, Chiayi County, Taiwan (China)

2015-06-15

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.

Evidence of dose saving in routine CT practice using iterative reconstruction derived from a national diagnostic reference level survey.

Science.gov (United States)

Thomas, P; Hayton, A; Beveridge, T; Marks, P; Wallace, A

2015-09-01

To assess the influence and significance of the use of iterative reconstruction (IR) algorithms on patient dose in CT in Australia. We examined survey data submitted to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) National Diagnostic Reference Level Service (NDRLS) during 2013 and 2014. We compared median survey dose metrics with categorization by scan region and use of IR. The use of IR results in a reduction in volume CT dose index of between 17% and 44% and a reduction in dose-length product of between 14% and 34% depending on the specific scan region. The reduction was highly significant (p sum test) for all six scan regions included in the NDRLS. Overall, 69% (806/1167) of surveys included in the analysis used IR. The use of IR in CT is achieving dose savings of 20-30% in routine practice in Australia. IR appears to be widely used by participants in the ARPANSA NDRLS with approximately 70% of surveys submitted employing this technique. This study examines the impact of the use of IR on patient dose in CT on a national scale.

Cuban typical doses for 99mTc-DMSA renal gammagraphy studies: a methodology for the establishment of reference levels

International Nuclear Information System (INIS)

Diaz Barreto, M.; Varela Corona, C.; Lopez Bejerano, G.M.; Perea Diaz, M.; Paz Viera, J.E.

2008-01-01

Since a handful of years ago, international rules on Radiological Protection include the principle of optimization of given dose to patients, if this procedure doesn't lessen diagnosis quality, and the establishment of reference levels of activity. For these reasons, the Radiological Protection staff of Cuban Institute of Nephrology's Nuclear Medicine Service, where morpho functional renal studies are carried out, 70% on infants and young children, started a research on that way. Thus, because their biggest incidence, 99m Tc -DMSA renal gammagraphy studies were chosen, using a General Electric 400 AT Planar Gamma Camera. Studied sample was randomly selected, including adults (12 peoples) and children (23); divided into 4 groups, lessen given dose step by step. Other items were kept in mind in the research, such age, weight, time delayed between administrations and image getting, getting time of each view and total time of the study, as well as radiopharmaceuticals quality and Gamma Camera performance. Image quality was evaluated for each case, using both, objective and subjective criteria. Objective evaluation was done by using contrast/noise ratios and variance of the random noise. They were used to develop clustering and discriminant analysis over the independent variables to detect groups with differentiated image quality from the physical and mathematical point of view. Subjective evaluation was performed using the criteria of two expert observers who had no information about the activity levels used. They evaluated image quality separately, giving a good, regular or bad evaluation for each image. As a conclusion, we found that it is possible to reduce the given activities in 50% and thus, indirectly, to reduce doses for workers and for the public. Additionally, we propose a methodology for the establishment of reference levels for 99m Tc -DMSA renal gammagraphy studies in Cuba, both, for adults and paediatric patients. (author)

Diagnostic Reference Levels in the 1990 and 1996 Recommendations of the ICRP (invited paper)

International Nuclear Information System (INIS)

Drexler, G.

1998-01-01

A review of and some comments on the paragraphs in the ICRP Publications 60 and 73 are presented, which are relevant to diagnostic reference doses. The content of the statements is traced back by approximately 50 years when ICRP's preoccupation with the future health and well-being of the population is reflected in guidance for characterisation of 'normal operational conditions'. The early ICRP levels of reference doses are compared with the values currently discussed to demonstrate the importance of diagnostic reference doses in the process of optimisation and to show the importance of a continuous review and update of these levels. (author)

Dose limits, constraints, reference levels. What does it mean for radiation protection?; Grenzwerte, Richtwerte, Referenzwerte. Was bedeutet das fuer den Strahlenschutz

Energy Technology Data Exchange (ETDEWEB)

Breckow, J. [Technische Hochschule Mittelhessen (THM), Giessen (Germany). Inst. fuer Medizinische Physik und Strahlenschutz (IMPS)

2016-07-01

The established concept of radiation protection with its basic principles justification, optimization, and limitation has proved its value and is going to be continued. In its deeper meaning, however, the concept is rather subtle and complex. Furthermore, in some aspects there remain some breaches or inconsistencies. This is just true for the terms dose limit, reference lever, and constraint that are tightly associated with the radiation protection principles. In order to guarantee the ability of radiation protection in whole extent, the subtle differences of meaning have to be communicated. There is a permanent need to defend the conceptual function of these terms against deliberate or undeliberate misinterpretations. Reference levels are definitely not the same as dose limits and they may not be misused as such. Any attempt to misinterpret fundamental radiation protection principles for selfish purposes should discouraged vigorously.

Methodology for setting the reference levels in the measurements of the dose rate absorbed in air due to the environmental gamma radiation

International Nuclear Information System (INIS)

Dominguez Ley, Orlando; Capote Ferrera, Eduardo; Caveda Ramos, Celia; Alonso Abad, Dolores

2008-01-01

Full text: The methodology for setting the reference levels of the measurements of the gamma dose rate absorbed in the air is described. The registration level was obtained using statistical methods. To set the alarm levels, it was necessary to begin with certain affectation level, which activates the investigation operation mode when being reached. It is was necessary to transform this affectation level into values of the indicators selected to set the appearance of an alarm in the network, allowing its direct comparison and at the same time a bigger operability of this one. The affectation level was assumed as an effective dose of 1 mSv/y, which is the international dose limit for public. The conversion factor obtained in a practical way as a consequence of the Chernobyl accident was assumed, converting the value of annual effective dose into values of effective dose rate in air. These factors are the most important in our work, since the main task of the National Network of Environmental Radiological Surveillance of the Republic of Cuba is detecting accidents with a situations regional affectation, and this accident is precisely an example of pollution at this scale. The alarm level setting was based on the results obtained in the first year of the Chernobyl accident. For this purpose, some transformations were achieved. In the final results, a correction factor was introduced depending on the year season the measurement was made. It was taken into account the influence of different meteorological events on the measurement of this indicator. (author)

A New Dual-purpose Quality Control Dosimetry Protocol for Diagnostic Reference-level Determination in Computed Tomography.

Science.gov (United States)

Sohrabi, Mehdi; Parsi, Masoumeh; Sina, Sedigheh

2018-05-17

A diagnostic reference level is an advisory dose level set by a regulatory authority in a country as an efficient criterion for protection of patients from unwanted medical exposure. In computed tomography, the direct dose measurement and data collection methods are commonly applied for determination of diagnostic reference levels. Recently, a new quality-control-based dose survey method was proposed by the authors to simplify the diagnostic reference-level determination using a retrospective quality control database usually available at a regulatory authority in a country. In line with such a development, a prospective dual-purpose quality control dosimetry protocol is proposed for determination of diagnostic reference levels in a country, which can be simply applied by quality control service providers. This new proposed method was applied to five computed tomography scanners in Shiraz, Iran, and diagnostic reference levels for head, abdomen/pelvis, sinus, chest, and lumbar spine examinations were determined. The results were compared to those obtained by the data collection and quality-control-based dose survey methods, carried out in parallel in this study, and were found to agree well within approximately 6%. This is highly acceptable for quality-control-based methods according to International Atomic Energy Agency tolerance levels (±20%).

Dose reference levels in Spanish intraoral dental radiology: stabilisation of the incorporation of digital systems in dental clinical practices

International Nuclear Information System (INIS)

Alcaraz, M.; Velasco, F.; Olivares, A.; Velasco, E.; Canteras, M.

2016-01-01

A total of 34 044 official quality assurance reports in dental radiodiagnostic surgery from 16 regions of Spain, compiled from 2002 to 2014, were studied in order to determine the progress of diagnostic reference levels (DRLs) for obtaining diagnostic images under normal conditions for clinical practice in Spanish dental clinics. A DRL of 2.8 mGy was set in 2014, which represents a 41.7 % decrease compared with that of 2002 (4.8 mGy). Over the same time period, the mean dose fell by 55.2 %. However, over the last 3 y, the stabilisation of the mean dose administered to patients has been observed with only a 6.7 % reduction in DRLs, which corresponds to the stabilisation of dental radiodiagnostic surgery on replacing the use of radiographic film with digital imaging systems. (authors)

Determination of dose to patient in different teams of TC and assessment with international reference levels

International Nuclear Information System (INIS)

Ruiz Morales, C.; Fernandez lara, A. A.; Buades Forner, M. J.; Tobarra Gonzalez, B. M.

2013-01-01

The increase in CT studies and the differences observed between the different equipment used in our hospital prompted us to determine the doses to patients in different studies and check the results obtained with the reference values published internationally. (Author)

A reference dosimetric system for dose interval of radiotherapy based on alanine/RPE

International Nuclear Information System (INIS)

Rodrigues Junior, Orlando; Galante, Ocimar L.; Campos, Leticia L.

2001-01-01

This work describes the development of a reference dosimetric system based on alanine/EPR for radiotherapy dose levels. Currently the IPEN is concluding a similar system for the dose range used for irradiation of products, 10-10 5 Gy. The objective of this work is to present the efforts towards to improve the measure accuracy for doses in the range between 1-10 Gy. This system could be used as reference by radiotherapy services, as much in the quality control of the equipment, as for routine accompaniment of more complex handling where the total doses can reach some grays. The system uses alanine as detector and electronic paramagnetic resonance - EPR as measure technique. To reach accuracy better than 5% mathematical studies on the best optimization of the EPR spectrometer parameters and methods for the handling of the EPR sign are discussed. (author)

Medical reference dosimetry using EPR measurements of alanine: Development of an improved method for clinical dose levels

International Nuclear Information System (INIS)

Helt-Hansen, Jakob; Andersen, Claus Erik; Rosendal, Flemming; Kofoed, Inger Matilde

2009-01-01

Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low signal fading, non-destructive measurement and small dosimeter size. Material and Methods. A Bruker EMX-micro EPR spectrometer with a rectangular cavity and a measurement time of two minutes per dosimeter was used for reading of irradiated alanine dosimeters. Under these conditions a new algorithm based on scaling of known spectra was developed to extract the alanine signal. Results. The dose accuracy, including calibration uncertainty, is less than 2% (k=1) above 4 Gy (n=4). The measurement uncertainty is fairly constant in absolute terms (∼30 mGy) and the relative uncertainty therefore rises for dose measurements below 4 Gy. Typical reproducibility is <1% (k=1) above 10 Gy and <2% between 4 and 10 Gy. Below 4 Gy the uncertainty is higher. A depth dose curve measurement was performed in a solid-water phantom irradiated to a dose of 20 Gy at the maximum dose point (dmax) in 6 and 18 MV photon beams. The typical difference between the dose measured with alanine in solid water and the dose measured with an ion chamber in a water tank was about 1%. A difference of 2% between 6 and 18 MV was found, possibly due to non-water equivalence of the applied phantom. Discussion. Compared to previously published methods the proposed algorithm can be applied without normalisation of phase shifts caused by changes in the g-value of the cavity. The study shows that alanine dosimetry is a suitable candidate for medical reference dosimetry especially for quality control applications

Derivation of a reference dose and drinking water equivalent level for 1,2,3-trichloropropane.

Science.gov (United States)

Tardiff, Robert G; Carson, M Leigh

2010-06-01

In some US potable water supplies, 1,2,3-trichloropropane (TCP) has been present at ranges of non-detect to less than 100 ppb, resulting from past uses. In subchronic oral studies, TCP produced toxicity in kidneys, liver, and other tissues. TCP administered by corn oil gavage in chronic studies produced tumors at multiple sites in rats and mice; however, interpretation of these studies was impeded by substantial premature mortality. Drinking water equivalent levels (DWELs) were estimated for a lifetime of consumption by applying biologically-based safety/risk assessment approaches, including Monte Carlo techniques, and with consideration of kinetics and modes of action, to possibly replace default assumptions. Internationally recognized Frameworks for human relevance of animal data were employed to interpret the findings. Calculated were a reference dose (=39 microg/kg d) for non-cancer and Cancer Values (CV) (=10-14 microg/kg d) based on non-linear dose-response relationships for mutagenicity as a precursor of cancer. Lifetime Average Daily Intakes (LADI) are 3130 and 790-1120 microg/person-d for non-cancer and cancer, respectively. DWELs, estimated by applying a relative source contribution (RSC) of 50% to the LADIs, are 780 and 200-280 microg/L for non-cancer and cancer, respectively. These DWELs may inform establishment of formal/informal guidelines and standards to protect public health. Copyright 2010 Elsevier Ltd. All rights reserved.

A system for environmental protection. Reference dose models for fauna and flora

International Nuclear Information System (INIS)

Pentreath, R.J.; Woodhead, D.S.

2000-01-01

Ideas have already been published on how the current problems relating to environmental protection could be explicitly addressed. One of the basic cornerstones of the proposed system is that of the use of reference dose models for fauna and flora, in a manner analogous to those used for the human species. The concept is that, for a number of both aquatic and terrestrial fauna and flora types, 'reference' dose models, and dose per unit (internal and external) exposure tables, could be compiled. These would then be used to draw broad conclusions on the likely effects for such organisms in relation to three broad environment end points of concern: life shortening; impairment of reproductive capacity; and scorable, cytogenetic damage. The level of complexity of the dose models needs to be commensurate with the morphological complexity of the modelled organism, its size, and the data bases which are either available or could be reasonably obtained. The most basic models considered are either solid ellipsoids or spheres, with fixed dimensions. Secondary models contain internal, but relatively simple geometric features representative of those key organs or tissues for which more precise estimates of dose are required. Their level of complexity is also a function of different internal and external sources of radiation, and expected differences in radiosensitivities. Tertiary models -of greater complexity- are only considered to be of value for higher vertebrates. The potential derivation and use of all three sets of models is briefly discussed. (author)

Comparison between dose values specified at the ICRU reference point and the mean dose to the planning target volume

International Nuclear Information System (INIS)

Kukoowicz, Pawel F.; Mijnheer, Bernard J.

1997-01-01

Background and purpose: To compare dose values specified at the reference point, as recommended by the International Commission on Radiation Units and Measurements, ICRU, and the mean dose to the planning target volume, PTV. Material and methods: CT-based dose calculations were performed with a 3-D treatment planning system for 6 series of patients treated for bladder, brain, breast, lung, oropharynx and parotid gland tumour. All patients were arbitrarily chosen from a set of previously treated patients irradiated with a two- or three-field technique using customised blocks. Appropriate wedge angles and beam weights were chosen to make the dose distribution as homogeneous as possible. Results: The dose at the ICRU reference point was generally higher than the mean dose to the PTV. The difference between the ICRU reference dose and the mean dose to the PTV for an individual patient was less than 3% in 88% of cases and less than 2% in 72% of the cases. The differences were larger in those patients where the dose distribution is significantly influenced by the presence of lungs or air gaps. For each series of patients the mean difference between the ICRU reference dose and the mean dose to the PTV was calculated. The difference between these two values never exceeded 2%. Because not all planning systems are able to calculate the mean dose to the PTV, the concept of the mean central dose, the mean of the dose values at the centre of the PTV in each CT slice, has been introduced. The mean central dose was also calculated for the same patients and was closer to the mean dose to the PTV than the ICRU reference dose. Conclusion: The mean dose to the PTV is well estimated by either the ICRU reference dose or the mean central dose for a variety of treatment techniques for common types of cancer

Introduction of guidance dose levels inpaediatrics CT

International Nuclear Information System (INIS)

Verdun, F.R.; Valley, J.F.; Bernasconi, M.; Schnyder, P.; Gudinchet, F.

2001-01-01

The purpose of this work is to present a methodology in order to define reference levels for chest or abdominal CT examinations performed on children. For children aged from 0 to 6 the CTDI w measured in the head test object (i.e. diameter 16 cm) should be used as a dose indicator. For children older than 12 years old the CTDI w measured in the body test object (i.e. 32 cm) should be used as a dose indicator. For children aged between 6 to 12 we propose to use an intermediate CTDI w in order to avoid an over or underestimation of the dose delivered in the slices. Finally a set of dose length products (DLP) measured in our centre for standard abdominal acquisitions will be given. (author)

Application of diagnostic reference levels in medical practice

Energy Technology Data Exchange (ETDEWEB)

Bourguignon, Michel [Faculty of Medicine of Paris, Deputy Director General, Nuclear Safety Authority (ASN), Paris (France)

2006-07-01

Diagnosis reference levels (D.R.L.) are defined in the Council Directive 97/43 EURATOM as 'Dose levels in medical radio diagnosis practices or in the case of radiopharmaceuticals, levels of activity, for typical examinations for groups of standards-sized patients or standards phantoms for broadly defined types of equipment. These levels are expected not to be exceeded for standard procedures when good and normal practice regarding diagnostic and technical performance is applied'. Thus D.R.L. apply only to diagnostic procedures and does not apply to radiotherapy. Radiation protection of patients is based on the application of 2 major radiation protection principles, justification and optimization. The justification principle must be respected first because the best way to protect the patient is not to carry a useless test. Radiation protection of the patient is a continuous process and local dose indicator values in the good range should not prevent the radiologist or nuclear medicine physician to continue to optimize their practice. (N.C.)

Application of diagnostic reference levels in medical practice

International Nuclear Information System (INIS)

Bourguignon, Michel

2006-01-01

Diagnosis reference levels (D.R.L.) are defined in the Council Directive 97/43 EURATOM as 'Dose levels in medical radio diagnosis practices or in the case of radiopharmaceuticals, levels of activity, for typical examinations for groups of standards-sized patients or standards phantoms for broadly defined types of equipment. These levels are expected not to be exceeded for standard procedures when good and normal practice regarding diagnostic and technical performance is applied'. Thus D.R.L. apply only to diagnostic procedures and does not apply to radiotherapy. Radiation protection of patients is based on the application of 2 major radiation protection principles, justification and optimization. The justification principle must be respected first because the best way to protect the patient is not to carry a useless test. Radiation protection of the patient is a continuous process and local dose indicator values in the good range should not prevent the radiologist or nuclear medicine physician to continue to optimize their practice. (N.C.)

Patient dose reference values for explorations of radiodiagnostic

International Nuclear Information System (INIS)

Vano, E.; Gonzalez, L.; Moran, P.; Calzado, A.; Delgado, V.; Ruiz, M.J.

1992-01-01

Among the results of the research programs developed in the European Community dealing with radiological protection, dose estimation and quality control in radiodiagnostics, the preparation of a document on Quality criteria for radiodiagnostic images is worthy of note. This document proposes criteria for image quality and patient dose reference values for explorations of thorax, cranium, lumbar region, pelvis, urinary tract and breast. Said reference values, while indicative, are merely an average approximation, from which the radiodiagnostic services of each area may differ significantly, as can be deduced from a EC-coordinated project. With this in mind, and following a strategy applied in the EC to establish said reference values, in this report, provisional reference values, specific for Spain, are proposed for simple examinations (those analyzed by the group of EC experts, among others) and complex probes (intravenous urography, opaque enema and esophagogastroduodenal enema). (author)

Studies on the reference Korean and estimation of radiation exposure dose

International Nuclear Information System (INIS)

Kim, Y.J.; Lee, K.S.; Chun, K.J.; Kim, J.B.; Chung, G.H.; Kim, S.R.

1982-01-01

For the purpose of establishment of Reference Korean and estimation of internal and external exposure doses in the Reference Korean, we have surveyed reference values for Koreans such as physical standards including height, weight, and body surface area, food consumption rate of daily intake of radioactive substances and exposure dose from natural radiation. (Author)

Establishment of multi-slice computed tomography (MSCT) reference level in Johor, Malaysia

Science.gov (United States)

Karim, M. K. A.; Hashim, S.; Bakar, K. A.; Muhammad, H.; Sabarudin, A.; Ang, W. C.; Bahruddin, N. A.

2016-03-01

Radiation doses from computed tomography (CT) are the highest and most hazardous compared to other imaging modalities. This study aimed to evaluate radiation dose in Johor, Malaysia to patients during computed tomography examinations of the brain, chest and abdomen and to establish the local diagnostic reference levels (DRLs) as are present with the current, state- of-art, multi-slice CT scanners. Survey forms were sent to five centres performing CT to obtain data regarding acquisition parameters as well as the dose information from CT consoles. CT- EXPO (Version 2.3.1, Germany) was used to validate the dose information. The proposed DRLs were indicated by rounding the third quartiles of whole dose distributions where mean values of CTDIw (mGy), CTDIvol (mGy) and DLP (mGy.cm) were comparable with other reference levels; 63, 63, and 1015 respectively for CT Brain; 15, 14, and 450 respectively for CT thorax and 16, 17, and 590 respectively for CT abdomen. The study revealed that the CT practice and dose output were revolutionised, and must keep up with the pace of introductory technology. We suggest that CTDIvol should be included in current national DRLs, as modern CTs are configured with a higher number of detectors and are independent of pitch factors.

Establishment of multi-slice computed tomography (MSCT) reference level in Johor, Malaysia

International Nuclear Information System (INIS)

Karim, M K A; Hashim, S; Ang, W C; Bahruddin, N A; Bakar, K A; Muhammad, H; Sabarudin, A

2016-01-01

Radiation doses from computed tomography (CT) are the highest and most hazardous compared to other imaging modalities. This study aimed to evaluate radiation dose in Johor, Malaysia to patients during computed tomography examinations of the brain, chest and abdomen and to establish the local diagnostic reference levels (DRLs) as are present with the current, state- of-art, multi-slice CT scanners. Survey forms were sent to five centres performing CT to obtain data regarding acquisition parameters as well as the dose information from CT consoles. CT- EXPO (Version 2.3.1, Germany) was used to validate the dose information. The proposed DRLs were indicated by rounding the third quartiles of whole dose distributions where mean values of CTDI w (mGy), CTDI vol (mGy) and DLP (mGy.cm) were comparable with other reference levels; 63, 63, and 1015 respectively for CT Brain; 15, 14, and 450 respectively for CT thorax and 16, 17, and 590 respectively for CT abdomen. The study revealed that the CT practice and dose output were revolutionised, and must keep up with the pace of introductory technology. We suggest that CTDI vol should be included in current national DRLs, as modern CTs are configured with a higher number of detectors and are independent of pitch factors. (paper)

Local diagnostic reference levels at the Portuguese Institute of oncology francisco gentil of coimbra

International Nuclear Information System (INIS)

Bras, S.; Sousa, M.C. de; Lopes, M.C.

2006-01-01

In the scope of medical radiological exposures and according to European recommendations and national legal requirements [14], the maximum responsible for an installation must assure the establishment of local dose levels for each type of radiological examination and also assure that they are available for the doctor who prescribes the examination. In the absence of national reference dose levels, the so called Local Diagnostic Reference Levels (L.D.R.L.) should be in agreement with the European Diagnostic Reference Levels published for the different types of medical exposures. The aim of this work was to establish a protocol of measurement for each type of more frequent examination, namely in conventional radiology, in CT and in mammography performed in our hospital. For each kind of examination the recommended dose descriptor was adopted and directly measured or derived from basic charge measurements. The patient sample corresponded in each case to at least a minimum of 10 standard-sized patients, as recommended, in order to obtain averages that constitute for each type of radiological examination the L.D.R.L. that could be compared with the European D.R.L.. The results obtained are in the large majority of the situations below the corresponding D.R.L.. Nevertheless we have identified some situations that deserve more attention.In conventional radiology all L.D.R.L. are below the reference levels. However we have detected some skull post anterior (skull P.A.) exposures where entrance skin doses exceeded the standard value. This may be due to equipment age problems but, as always, improvement of staff education will contribute to better practices and we hope that this work can contribute to this objective. In CT the L.D.R.L. that corresponds to single slice scan meet the standards whereas complete examinations described by dose length product (D.L.P.) values show a larger variation and also some situations where the reference level is exceeded. It is possible that

Local diagnostic reference levels at the Portuguese Institute of oncology francisco gentil of coimbra

Energy Technology Data Exchange (ETDEWEB)

Bras, S.; Sousa, M.C. de [Algarve Univ., LIP-Algarve, FCT (Portugal); Lopes, M.C. [IPOFG-CROC, S.A., Medical Physics Dept., Coimbra (Portugal)

2006-07-01

In the scope of medical radiological exposures and according to European recommendations and national legal requirements [14], the maximum responsible for an installation must assure the establishment of local dose levels for each type of radiological examination and also assure that they are available for the doctor who prescribes the examination. In the absence of national reference dose levels, the so called Local Diagnostic Reference Levels (L.D.R.L.) should be in agreement with the European Diagnostic Reference Levels published for the different types of medical exposures. The aim of this work was to establish a protocol of measurement for each type of more frequent examination, namely in conventional radiology, in CT and in mammography performed in our hospital. For each kind of examination the recommended dose descriptor was adopted and directly measured or derived from basic charge measurements. The patient sample corresponded in each case to at least a minimum of 10 standard-sized patients, as recommended, in order to obtain averages that constitute for each type of radiological examination the L.D.R.L. that could be compared with the European D.R.L.. The results obtained are in the large majority of the situations below the corresponding D.R.L.. Nevertheless we have identified some situations that deserve more attention.In conventional radiology all L.D.R.L. are below the reference levels. However we have detected some skull post anterior (skull P.A.) exposures where entrance skin doses exceeded the standard value. This may be due to equipment age problems but, as always, improvement of staff education will contribute to better practices and we hope that this work can contribute to this objective. In CT the L.D.R.L. that corresponds to single slice scan meet the standards whereas complete examinations described by dose length product (D.L.P.) values show a larger variation and also some situations where the reference level is exceeded. It is possible that

Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values

Energy Technology Data Exchange (ETDEWEB)

Ubeda, Carlos, E-mail: cubeda@uta.cl [Medical Technology Department, Radiological Sciences Center, Health Sciences Faculty, Tarapaca University, Arica 1000000 (Chile); Miranda, Patricia [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Santiago 7500539 (Chile); Vano, Eliseo [Radiology Department, Faculty of Medicine, Complutense University and IdIS, San Carlos Hospital, Madrid 28040 (Spain)

2015-02-15

Purpose: To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Methods: Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Results: Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm{sup 2} for <1 yr; 1.74 and 1.90 Gy cm{sup 2} for 1 to <5 yr; 2.83 and 3.22 Gy cm{sup 2} for 5 to <10 yr; and 7.34 and 8.68 Gy cm{sup 2} for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm{sup 2}/kg) for diagnostic and therapeutic procedures. Conclusions: The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there

Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values

International Nuclear Information System (INIS)

Ubeda, Carlos; Miranda, Patricia; Vano, Eliseo

2015-01-01

Purpose: To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. Methods: Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. Results: Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm 2 for <1 yr; 1.74 and 1.90 Gy cm 2 for 1 to <5 yr; 2.83 and 3.22 Gy cm 2 for 5 to <10 yr; and 7.34 and 8.68 Gy cm 2 for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm 2 /kg) for diagnostic and therapeutic procedures. Conclusions: The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences

A comparison of mean glandular dose diagnostic reference levels within the all-digital irish national breast screening programme and the Irish symptomatic breast services

International Nuclear Information System (INIS)

O'Leary, D.; Rainford, L.

2013-01-01

Data on image quality, compression and radiation dose were collected from symptomatic breast units within the Republic of Ireland. Quantitative and qualitative data were analysed using SPSS. Recommendations of mean glandular dose (MGD) diagnostic reference levels were made at various levels for film-screen and full field digital mammography units to match levels published worldwide. MGDs received by symptomatic breast patients within Ireland are higher than those received in the all-digital Irish Breast Screening service; 55-65 mm breast: 1.75 mGy (screening) vs. 2.4 mGy (symptomatic) at the 95. percentile; various reasons are proposed for the differences. MGDs achieved in the screening service may be lower because of the exacting requirements for radiographer training, characteristics of the patients and equipment quality assurance levels. More precise imaging guidelines, standards and training of symptomatic radiographers performing mammography are suggested to remediate MGDs delivered to the breasts of Irish women attending the symptomatic breast services. (authors)

Swiss National Reference Levels in Fluoroscopy

International Nuclear Information System (INIS)

Aroua, A.; Baechler, S.; Verdun, F.R.; Rickli, H.; Trueb, Ph.R.; Vock, P.

2006-01-01

A nationwide survey was launched in Switzerland in order to investigate the use of fluoroscopy and to establish national reference levels (R.L.) for dose-intensive procedures particularly in interventional radiology. The 2-year investigation covered 5 radiology and 9 cardiology departments in public hospitals and private clinics, and focused on twelve types of examinations: six diagnostic and six interventional. The performance of the fluoroscopy units used in these health-care centres (image quality and dose) was assessed extensively and 1000 examinations were registered. Information on the fluoroscopy time (T), the number of frames (N), the dose-area product (D.A.P.), the difficulty of the case, the age, gender, height and weight of the patient, as well as the experience of the practitioner was provided. The whole set of data was used in relative values (to the mean values for each type of examination) to establish the distributions of T, N and the D.A.P.. From these distributions a set of R.L. values was deduced for the types of examinations investigated using the 3.-quartile method. The R.L. values found are compared to the data published in the literature. (authors)

Reference doses and patient size in paediatric radiology

International Nuclear Information System (INIS)

Hart, D.; Wall, B.; Shrimpton, P.

2000-01-01

There is a wide range in patient size from a newborn baby to a 15 year old adolescent. Reference doses for paediatric radiology can sensibly be established only for specific sizes of children. Here five standard sizes have been chosen, representing 0 (newborn), 1, 5, 10 and 15 year old patients. This selection of standard ages has the advantage of matching the paediatric mathematical phantoms which are often used in Monte Carlo organ dose calculations. A method has been developed for calculating factors for normalising doses measured on individual children to those for the nearest standard-sized 'child'. These normalisation factors for entrance surface dose (ESD) and dose-area product (DAP) measurements depend on the thickness of the real child, the thickness of the nearest standard 'child', and an effective linear attenuation coefficient (μ) which is itself a function of the x-ray spectrum, the field size, and whether or not an antiscatter grid is used. Entrance and exit dose measurements were made with phantom material representing soft tissue to establish μ values for abdominal and head examinations, and with phantom material representing lung for chest examinations. These measurements of μ were confirmed and extended to other x-ray spectra and field sizes by Monte Carlo calculations. The normalisation factors are tabulated for ESD measurements for specific radiographic projections through the head and trunk, and for DAP measurements for complete multiprojection examinations in the trunk. The normalisation factors were applied to European survey data for entrance surface dose and dose-area product measurements to derive provisional reference doses for common radiographic projections and for micturating cystourethrography (MCU) examinations - the most frequent fluoroscopic examination on children. (author)

Guidance document for setting an Acute Reference Dose in Dutch national pesticide evaluations

NARCIS (Netherlands)

Raaij MTM van; CSR

2001-01-01

This report describes a proposal for the procedures for setting an Acute Reference Dose (ARfD) for pesticides evaluated in the Netherlands. This deals with both evaluations on the national level (on behalf of the Dutch Board for the Authorisation of Pesticides (CTB)) and evaluations at the European

ICRU reference dose in an era of intensity-modulated radiation therapy clinical trials: Correlation with planning target volume mean dose and suitability for intensity-modulated radiation therapy dose prescription

International Nuclear Information System (INIS)

Yaparpalvi, Ravindra; Hong, Linda; Mah, Dennis; Shen Jin; Mutyala, Subhakar; Spierer, Marnee; Garg, Madhur; Guha, Chandan; Kalnicki, Shalom

2008-01-01

Background and Purpose: IMRT clinical trials lack dose prescription and specification standards similar to ICRU standards for two- and three-dimensional external beam planning. In this study, we analyzed dose distributions for patients whose treatment plans incorporated IMRT, and compared the dose determined at the ICRU reference point to the PTV doses determined from dose-volume histograms. Additionally, we evaluated if ICRU reference type single-point dose prescriptions are suitable for IMRT dose prescriptions. Materials and methods: For this study, IMRT plans of 117 patients treated at our institution were randomly selected and analyzed. The treatment plans were clinically applied to the following disease sites: abdominal (11), anal (10), brain (11), gynecological (15), head and neck (25), lung (15), male pelvis (10) and prostate (20). The ICRU reference point was located in each treatment plan following ICRU Report 50 guidelines. The reference point was placed in the central part of the PTV and at or near the isocenter. In each case, the dose was calculated and recorded to this point. For each patient - volume and dose (PTV, PTV mean, median and modal) information was extracted from the planned dose-volume histogram. Results: The ICRU reference dose vs PTV mean dose relationship in IMRT exhibited a weak positive association (Pearson correlation coefficient 0.63). In approximately 65% of the cases studied, dose at the ICRU reference point was greater than the corresponding PTV mean dose. The dose difference between ICRU reference and PTV mean doses was ≤2% in approximately 79% of the cases studied (average 1.21% (±1.55), range -4% to +4%). Paired t-test analyses showed that the ICRU reference doses and PTV median doses were statistically similar (p = 0.42). The magnitude of PTV did not influence the difference between ICRU reference and PTV mean doses. Conclusions: The general relationship between ICRU reference and PTV mean doses in IMRT is similar to that

Dose distribution in organs: patient-specific phantoms versus reference phantoms

Energy Technology Data Exchange (ETDEWEB)

Lacerda, I.V.B., E-mail: isabelle.lacerda@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife (Brazil); Vieira, J.W. [Instituto Federal de Pernambuco (IFPE), Recife (Brazil); Oliveira, M.L.; Lima, F.R.A. [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PB), Recife (Brazil)

2017-07-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Dose distribution in organs: patient-specific phantoms versus reference phantoms

International Nuclear Information System (INIS)

Lacerda, I.V.B.; Vieira, J.W.; Oliveira, M.L.; Lima, F.R.A.

2017-01-01

Discrepancies between ICRP phantoms and real patients lead to disparities on patient-dose estimations. This paper aims to compare distribution of dose in organs of male/female specific-phantoms and ICRP reference phantoms. The absorbed dose estimation was performed using the EGSnrc Monte Carlo code and a parallel source algorithm. In this work were used a patient-specific phantom for a man (1.73m/70.3kg) and another for a woman (1.63m/60.3kg) and the male and female ICRP reference phantoms. The comparison of the absorbed dose from each phantom gender was performed using the relative error. The results were expressed in terms of conversion coefficients to brain, lungs, liver and kidneys. The greatest absolute relative error between the organs of the patient-specific phantom and the reference phantom was 22.92% in the liver and 62.84% in the kidneys, respectively for man and woman. There are errors that cannot be disregarded. This paper shows the need for a specific study for each patient or for the population of each country, since there are different body types, which affects the distribution of the organ doses. (author)

Cloud-based CT dose monitoring using the DICOM-structured report. Fully automated analysis in regard to national diagnostic reference levels

International Nuclear Information System (INIS)

Boos, J.; Rubbert, C.; Heusch, P.; Lanzman, R.S.; Aissa, J.; Antoch, G.; Kroepil, P.

2016-01-01

To implement automated CT dose data monitoring using the DICOM-Structured Report (DICOM-SR) in order to monitor dose-related CT data in regard to national diagnostic reference levels (DRLs). Materials and Methods: We used a novel in-house co-developed software tool based on the DICOM-SR to automatically monitor dose-related data from CT examinations. The DICOM-SR for each CT examination performed between 09/2011 and 03/2015 was automatically anonymized and sent from the CT scanners to a cloud server. Data was automatically analyzed in accordance with body region, patient age and corresponding DRL for volumetric computed tomography dose index (CTDI vol ) and dose length product (DLP). Results: Data of 36 523 examinations (131 527 scan series) performed on three different CT scanners and one PET/CT were analyzed. The overall mean CTDI vol and DLP were 51.3 % and 52.8 % of the national DRLs, respectively. CTDI vol and DLP reached 43.8 % and 43.1 % for abdominal CT (n = 10 590), 66.6 % and 69.6 % for cranial CT (n = 16 098) and 37.8 % and 44.0 % for chest CT (n = 10 387) of the compared national DRLs, respectively. Overall, the CTDI vol exceeded national DRLs in 1.9 % of the examinations, while the DLP exceeded national DRLs in 2.9 % of the examinations. Between different CT protocols of the same body region, radiation exposure varied up to 50 % of the DRLs. Conclusion: The implemented cloud-based CT dose monitoring based on the DICOM-SR enables automated benchmarking in regard to national DRLs. Overall the local dose exposure from CT reached approximately 50 % of these DRLs indicating that DRL actualization as well as protocol-specific DRLs are desirable. The cloud-based approach enables multi-center dose monitoring and offers great potential to further optimize radiation exposure in radiological departments.

Reappraisal of the reference dose distribution in the UNSCEAR 1977 report

International Nuclear Information System (INIS)

Kumazawa, Shigeru

2008-01-01

This paper provides the update of the reference dose distribution proposed by G.A.M. Web and D. Beninson in Annex E to the UNSCEAR 1977 Report. To demonstrate compliance with regulatory obligations regarding doses to individuals, they defined it with the following properties: 1) The distribution of annual doses is log-normal; 2) The mean of the annual dose distribution is 5 m Gy (10% of the ICRP 1977 dose limit); 3) The proportion of workers exceeding 50 m Gy is 0.1%. The concept of the reference dose distribution is still important to understand the inherent variation of individual doses to workers controlled by source-related and individual-related efforts of best dose reduction. In the commercial nuclear power plant, the dose distribution becomes the more apart from the log-normal due to the stronger ALARA efforts and the revised dose limits. The monitored workers show about 1 m Sv of annual mean and far less than 0.1% of workers above 20 m Sv. The updated models of dose distribution consist of log-normal (no feedback on dose X) ln(X)∼N(μ,σ 2 ), hybrid log-normal (feedback on higher X by ρ) hyb(ρX)=ρX+ln(ρX)∼N(μ,σ 2 ), hybrid S B (feedback on higher dose quotient X/(D-X) not close to D by ρ) hyb[ρX/(D.X)]∼N(μ,σ 2 ) and Johnson's S B (limit to D) ln[X/(D-X)]∼N(μ,σ 2 ). These models afford interpreting the degree of dose control including dose constraint/limit to the reference distribution. Some of distributions are examined to characterize the variation of doses to members of the public with uncertainty. (author)

Evolution of diagnostic reference levels in Spanish intraoral radiology

International Nuclear Information System (INIS)

Alcaraz, M.; Velasco, F.; Martinez-Beneyto, Y.; Alcaraz-Saura, M.; Velasco, E.; Achel, G. D.; Canteras, M.

2008-01-01

A total of 16 175 official reports of quality assurance on dental radiodiagnostic surgeries from 16 Spanish autonomous regions compiled during 2002-09 were studied to determine the evolution of diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice in Spanish dental clinics. A DRL of 3.1 mGy was set in 2009, which represents a 35.4 % decrease compared with the dose determined in 2002 (4.8 mGy). During the same period, the mean dose fell by only 17.2 %. The DRL recommended by the European Union in 2004 for intraoral radiology is 4 mGy, and this study shows that 83.4 % of the installations used a dose below this. Of the installations using indirect or direct digital systems 1.1 and 1.2 %, respectively, used doses higher than those recommended, while 14.2 % of those using radiographic film exceeded this limit. (authors)

ENRAF gauge reference level calculations

Energy Technology Data Exchange (ETDEWEB)

Huber, J.H., Fluor Daniel Hanford

1997-02-06

This document describes the method for calculating reference levels for Enraf Series 854 Level Detectors as installed in the tank farms. The reference level calculation for each installed level gauge is contained herein.

Estimates of diagnostic reference levels for common radiographic x-ray examinations in some sudanese hospitals

International Nuclear Information System (INIS)

Awad, Ezdehar Mohammed Satti.

2016-03-01

The objective of this study were to estimate patient dose in some common diagnostic x-ray examinations in Sudan with the aim to propose national diagnostic reference levels (DRLs). Radiation doses were estimated for the patients in 23 public hospitals in different town in Sudan (Wad-Madani, Kasala, Atbara Al obaid, Al nhod, Khartoum). Entrance surface air kerma (ESAK) was estimated in a three steps protocol: First, x-ray unit output Y (d) was measured at a distance at a distance (d) for different peak tube voltages and tube loading (mAs). Next, incident air kerma (k) was calculated from Y (d) using inverse square law combined with patient exposure factors. ESAK was calculated from k using backscatter factor, B. Mean ESAK values were comparable to those reported in other countries and are below reference dose levels. The estimated mean ESAK values were: 0.4, 1.9, 1.8, 3.2, 2.4, 3.5, and 8.4 mGy for chests . The estimated mean ESAK values were 0.4, 1.9, 1.8, 3.2, 2.4, 3,5, and 8.4 mGy for chest PA, Skull AP/PA, Skull LAT, Abdomen Pelvis AP, Lumber Spine AP and Lumber Spine LAT examination respectively. The results are used for dose optimization and to propose national diagnostic reference levels. (Author)

Remarks on reporting and recording consistent with the ICRU Reference Dose

Directory of Open Access Journals (Sweden)

Gainey Mark

2009-10-01

Full Text Available Abstract Background ICRU 50/62 provides a framework to facilitate the reporting of external beam radiotherapy treatments from different institutions. A predominant role is played by points that represent "the PTV dose". However, for new techniques like Intensity Modulated Radiotherapy (IMRT - especially step and shoot IMRT - it is difficult to define a point whose dose can be called "characteristic" of the PTV dose distribution. Therefore different volume based methods of reporting of the prescribed dose are in use worldwide. Several of them were compared regarding their usability for IMRT and compatibility with the ICRU Reference Point dose for conformal radiotherapy (CRT in this study. Methods The dose distributions of 45 arbitrarily chosen volumes treated by CRT plans and 57 volumes treated by IMRT plans were used for comparison. Some of the IMRT methods distinguish the planning target volume (PTV and its central part PTVx (PTV minus a margin region of × mm. The reporting of dose prescriptions based on mean and median doses together with the dose to 95% of the considered volume (D95 were compared with each other and in respect of a prescription report with the aid of one or several possible ICRU Reference Points. The correlation between all methods was determined using the standard deviation of the ratio of all possible pairs of prescription reports. In addition the effects of boluses and the characteristics of simultaneous integrated boosts (SIB were examined. Results Two types of methods result in a high degree of consistency with the hitherto valid ICRU dose reporting concept: the median dose of the PTV and the mean dose to the central part of the PTV (PTVx. The latter is similar to the CTV, if no nested PTVs are used and no patient model surfaces are involved. A reporting of dose prescription using the CTV mean dose tends to overestimate the plateau doses of the lower dose plateaus of SIB plans. PTVx provides the possibility to approach

Remarks on reporting and recording consistent with the ICRU Reference Dose

International Nuclear Information System (INIS)

Bratengeier, Klaus; Oechsner, Markus; Gainey, Mark; Flentje, Michael

2009-01-01

ICRU 50/62 provides a framework to facilitate the reporting of external beam radiotherapy treatments from different institutions. A predominant role is played by points that represent 'the PTV dose'. However, for new techniques like Intensity Modulated Radiotherapy (IMRT) - especially step and shoot IMRT - it is difficult to define a point whose dose can be called 'characteristic' of the PTV dose distribution. Therefore different volume based methods of reporting of the prescribed dose are in use worldwide. Several of them were compared regarding their usability for IMRT and compatibility with the ICRU Reference Point dose for conformal radiotherapy (CRT) in this study. The dose distributions of 45 arbitrarily chosen volumes treated by CRT plans and 57 volumes treated by IMRT plans were used for comparison. Some of the IMRT methods distinguish the planning target volume (PTV) and its central part PTV x (PTV minus a margin region of × mm). The reporting of dose prescriptions based on mean and median doses together with the dose to 95% of the considered volume (D 95 ) were compared with each other and in respect of a prescription report with the aid of one or several possible ICRU Reference Points. The correlation between all methods was determined using the standard deviation of the ratio of all possible pairs of prescription reports. In addition the effects of boluses and the characteristics of simultaneous integrated boosts (SIB) were examined. Two types of methods result in a high degree of consistency with the hitherto valid ICRU dose reporting concept: the median dose of the PTV and the mean dose to the central part of the PTV (PTV x ). The latter is similar to the CTV, if no nested PTVs are used and no patient model surfaces are involved. A reporting of dose prescription using the CTV mean dose tends to overestimate the plateau doses of the lower dose plateaus of SIB plans. PTV x provides the possibility to approach biological effects

Insignificant levels of dose

International Nuclear Information System (INIS)

Webb, G.A.M.; McLean, A.S.

1977-01-01

The procedures recommended by the International Commission on Radiological Protection (ICRP) for making decisions concerning controllable sources of radiation exposure of the public include 'justification' and 'optimisation'. The tool recommended by the ICRP for reaching these decisions is collective dose or dose commitment supplemented by consideration of doses to individuals. In both these considerations the practical problem arises of whether very small doses to large numbers of people should contribute to the final decision-making process. It may be that at levels of dose which are small increments on natural background, the relationship between dose and effect is linear even though the slope may be close to zero. If so, collective dose is a meaningful concept and the calculation of total detriment for the purpose of justification could legitimately include all doses. In the calculation of collective doses for the purpose of optimisation, which involves decisions on how much money or resource should be allocated to dose reduction, it is necessary to appraise radiation detriment realistically. At low levels of dose to the individual such as those small by comparison with variations in natural background within the UK, the risk to the individual is such that his well-being will not be significantly changed by the presence or absence of the radiation dose. These small doses, which are well below the point at which an individual attaches significance, should not carry a societal significance. Societal acceptance of risk is analysed with a view to assessing a level of possible risk, and hence dose, below which resources should not in general be diverted to secure further reduction. A formulation for collective dose commitment is proposed incorporating a cut-off to exclude insignificant doses. The implications of this formulation in practical situations are discussed

Reference handbook: Level detectors

International Nuclear Information System (INIS)

1990-01-01

The purpose of this handbook is to provide Rocky Flats personnel with the information necessary to understand level measurement and detection. Upon completion of this handbook you should be able to do the following: List three reasons for measuring level. Describe the basic operating principles of the sight glass. Demonstrate proper techniques for reading a sight glass. Describe the basic operating principles of a float level detector. Describe the basic operating principles of a bubbler level indicating system. Explain the differences between a wet and dry reference leg indicating system, and describe how each functions. This handbook is designed for use by experienced Rocky Flats operators to reinforce and improve their current knowledge level, and by entry-level operators to ensure that they possess a minimum level of fundamental knowledge. Level Detectors is applicable to many job classifications and can be used as a reference for classroom work or for self-study. Although this reference handbook is by no means all-encompassing, you will gain enough information about this subject area to assist you in contributing to the safe operation of Rocky Flats Plant

Preliminary Diagnostic Reference Levels of Adult CT at Aristide Ledantec National Hospital

International Nuclear Information System (INIS)

Diagne, M.; Gning, F.; Dieng, M. M.; Gueye, L.

2015-01-01

The number of Computed Tomography (CT) procedures performed in Senegal has widely increased as the CT is a powerful tool for the accurate and effective diagnosis. CT is a diagnostic imaging modality giving higher patient dose in comparison with other radiological procedures. The establishing of diagnostic reference levels (DRLs) is a way to optimize the radiation arising from CT procedures to as low as reasonable (ALARA) and to ensure good practice. Objective: The purpose of this study is to establish Local Diagnostic Reference Levels (LDRLs) at the University Hospital of Aristide LeDantec for CT examinations and to compare these values with the international Diagnostic Reference Levels (DRLs) to benchmark the local practice. Materials/Methods: This was a cross-sectional survey carried out in HALD between August 2014 and January 2015. Demographic data and acquisition parameters of 700 CT scan examinations performed on adult patients were collected from request forms and CT scan consoles. The values of CTDIw, CTDIvol and DLP were calculated using ImPACT (Imaging Performance and Assessment of Computed Tomography) software for Siemens Definition AS scanner of HALD. This was done by correlating the measurements from the National Radiological Protection Board (NRPB–R250) scanners with the effective dose calculated, using the CT–EXPO software. Data was analyzed using mean, range, 3rd quartile, as well as mean. Frequency tables and histogrammes were used to summarise the data. Results: The 3rd quartile doses in this study for head, chest, abdomen and pelvis were 89 mGy, 12 mGy, 16.5 mGy, and 15 mGy, respectively. These values were in good agreement with the values reported from the literature. (author)

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis

International Nuclear Information System (INIS)

Asplund, Sara A.; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus; Johnsson, Aase A.; Vikgren, Jenny; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A.

2014-01-01

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70 % of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100 % dose levels, respectively. The differences in FOM between the 12 % dose level and the 32, 70, and 100 % dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32 %. (orig.)

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis

Energy Technology Data Exchange (ETDEWEB)

Asplund, Sara A.; Svalkvist, Angelica; Maansson, Lars Gunnar; Baath, Magnus [University of Gothenburg, Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg (Sweden); Johnsson, Aase A.; Vikgren, Jenny; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A. [University of Gothenburg, Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Sahlgrenska University Hospital, Department of Radiology, Gothenburg (Sweden)

2014-07-15

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70 % of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100 % dose levels, respectively. The differences in FOM between the 12 % dose level and the 32, 70, and 100 % dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32 %. (orig.)

Quality assurance in CT: implementation of the updated national diagnostic reference levels using an automated CT dose monitoring system.

Science.gov (United States)

Appel, E; Kröpil, P; Bethge, O T; Aissa, J; Thomas, C; Antoch, G; Boos, J

2018-03-20

To evaluate the implementation of the updated computed tomography (CT) diagnostic reference levels (DRLs) from the German Federal Office for Radiation Protection into clinical routine using an automatic CT dose monitoring system. CT radiation exposure was analysed before and after implementing the updated national DRLs into routine clinical work in 2016. After the implementation process, institutional CT protocols were mapped to the anatomical regions for which DRLs were provided. Systematically, protocols that exceeded the thresholds were optimised and analysed in detail. The CT radiation output parameters analysed were volumetric CT dose index (CTDIvol) and dose-length product (DLP). Three radiologists evaluated subjective image quality using a three-point Likert scale. The study included 94,258 CT series (from 27,103 CT examinations) in adult patients performed in 2016. When averaged over all body regions with available DRL, institutional CTDIvol/DLP values were always below the DRLs (65.2±32.9%/67.3±41.5% initially; 59.4±32%/60.5±39.9% after optimisation). Values exceeding the national DRLs were found for pelvis (n=268; CTDIvol 107.7±65.7%/DLP 106.3±79.3%), lumbar spine (n=91; 160.8±74.7%/175.2±104.1%), and facial bones (n=527; 108±39%/152.7±75.7%). After optimisation, CTDIvol and DLP were 87.9±73%/87.8±80.8% for the pelvis, 67.8±33.2%/74.5±50.6% for the lumbar spine and 95.1±45.8%/133.3±74.6% for the viscerocranium. An automatic CT dose monitoring system enabled not only comprehensive monitoring of a DRL implementation process but can also help to optimise radiation exposure. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Exhaled nitric oxide levels in asthma: Personal best versus reference values.

Science.gov (United States)

Smith, Andrew D; Cowan, Jan O; Taylor, D Robin

2009-10-01

Factors affecting the fraction of nitric oxide in exhaled air (FE(NO)) are multiple. Interpreting values when assessing airways disease may be problematic. Clinically optimum levels have not been defined. We aimed to establish the relationship between predicted values for FE(NO) obtained from equations by Olin et al, Travers et al, and Dressel et al, and normalized levels after oral prednisone. We also compared postprednisone FE(NO) levels with those obtained during optimized treatment with inhaled fluticasone. Data were obtained before and after a trial of oral prednisone (30mg/d for 14 days), and also from a previously published study in which patients had their dose of inhaled corticosteroid adjusted using either FE(NO) or symptoms/lung function to optimize treatment. Seventy-three patients completed the study. The geometric mean FE(NO) after prednisone (17.7 parts per billion [ppb]; 95% CI, 15.5-20.2) was significantly lower than mean FE(NO) at the optimized fluticasone dose (20.2 ppb; 95% CI, 17.1-23.8; P=.04) and at loss of control (27.6 ppb; 95% CI, 22.8-33.4; P values of Olin et al (16.8 ppb, 95% CI, 16.0-17.5; P=.44), but were significantly lower than values of Travers et al (predicted, 21.5 ppb; 95% CI, 20.9-22.2; P=.005) and Dressel et al (predicted, 27.8 ppb; 95% CI, 26.7-28.9; P values from the reference equation by Olin et al. However, at optimized doses of inhaled corticosteroid, although FE(NO) levels were higher than predicted, asthma was well controlled. Targeting FE(NO) on reference values is not justified.

Computed Tomography (CT) radiation dose in children: A survey to propose regional diagnostic reference levels in Greater Accra-Ghana

International Nuclear Information System (INIS)

Addo, Patience

2016-07-01

The aim of this work was to assess the doses delivered to paediatric patients during computed tomography (CT) examinations of the head, chest and abdomen, and establishing regional diagnostic reference levels (RDRLs) for four age groups. The patient data, technique parameters and dose descriptors collected include: age, sex, tube voltage, tube current, rotation time, slice thickness, scan length, volume CT dose index (CTDI_v_o_l) and dose length product (DLP). Currently, paediatric CT examinations account for 11% of radiation exposure. For the paediatric age groups; < 1 year, (1-5 years), (6-10 years) and (11-15 years), the proposed RDRLs for head in terms of CTDI_v_o_l are (28, 38, 48 and 86 mGy) and in terms of DLP; (395, 487, 601, 1614 mGy cm) respectively. For Chest examinations, proposed RDRLs in terms of CTDI_v_o_l are (1 and 5 mGy) and in terms of DLP; (18 and 110 mGy cm) for age groups; < 1 year and (1-5 years) respectively. For Abdomino-pelvic examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 3 and 10 mGy) and in terms of DLP; (71, 120 and 494 mGy cm) for age groups; < 1 year, (1-5 years) and (6-10 years) respectively. For abdomen examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 5 and 5 mGy) and in terms of DLP; (83, 124 and 233 mGy cm) for age groups; < 1 year, (1-5 years) and (11-15 years) respectively. RDRLs have been proposed for CTDI_v_o_l and DLP for head, chest, abdomen and Abdomino-pelvic paediatric CT examinations in this study. An optimisation is required for 11-15 years age group for the DLP values which was higher than their corresponding international DRLs. For an effective optimization of patient protection a trade-off between image quality and patients doses studies should be investigated. (au)

DEVELOPMENT OF DIAGNOSTIC REFERENCE LEVELS (DRL OF PATIENTS X-RAY EXPOSURE IN DIAGNOSTIC RADIOLOGY

Directory of Open Access Journals (Sweden)

A. V. Vodovatov

2013-01-01

Full Text Available We introduce a system of Diagnostic Reference Levels (DRLs for patients medical exposure for national health care practice implementation. DRLs are an effective way of the patient radiation protection through the optimization of the medical exposure. The paper discusses and compares different methods of determining the DRLs based on measured and/or calculated quantities of patient’s dose: dose area product (DAP, entrance surface dose (ESD and an effective dose. Distributions of different dose quantities in different Saint-Petersburg clinics are shown on the example of chest PA examinations. The results are compared with the data from other sources. Regional DRLs for Saint-Petersburg are proposed.

Transatlantic Comparison of CT Radiation Doses in the Era of Radiation Dose-Tracking Software.

Science.gov (United States)

Parakh, Anushri; Euler, Andre; Szucs-Farkas, Zsolt; Schindera, Sebastian T

2017-12-01

The purpose of this study is to compare diagnostic reference levels from a local European CT dose registry, using radiation-tracking software from a large patient sample, with preexisting European and North American diagnostic reference levels. Data (n = 43,761 CT scans obtained over the course of 2 years) for the European local CT dose registry were obtained from eight CT scanners at six institutions. Means, medians, and interquartile ranges of volumetric CT dose index (CTDI vol ), dose-length product (DLP), size-specific dose estimate, and effective dose values for CT examinations of the head, paranasal sinuses, thorax, pulmonary angiogram, abdomen-pelvis, renal-colic, thorax-abdomen-pelvis, and thoracoabdominal angiogram were obtained using radiation-tracking software. Metrics from this registry were compared with diagnostic reference levels from Canada and California (published in 2015), the American College of Radiology (ACR) dose index registry (2015), and national diagnostic reference levels from local CT dose registries in Switzerland (2010), the United Kingdom (2011), and Portugal (2015). Our local registry had a lower 75th percentile CTDI vol for all protocols than did the individual internationally sourced data. Compared with our study, the ACR dose index registry had higher 75th percentile CTDI vol values by 55% for head, 240% for thorax, 28% for abdomen-pelvis, 42% for thorax-abdomen-pelvis, 128% for pulmonary angiogram, 138% for renal-colic, and 58% for paranasal sinus studies. Our local registry had lower diagnostic reference level values than did existing European and North American diagnostic reference levels. Automated radiation-tracking software could be used to establish and update existing diagnostic reference levels because they are capable of analyzing large datasets meaningfully.

Reference levels at diagnosis (NRD) for explorations in TC of the university Hospital Donostia

International Nuclear Information System (INIS)

Iriondo Igerabide, U.; Puertolas Hernandez, J. R.; Masso Odriozola, A.; Alonso Espinaco, M. t.; Pino Leon, C.; Lozano Flores, F. J.; Larretxea Etxarri, R.

2013-01-01

The objective of this work is the establishment of diagnostic reference levels in TC, for the anatomical regions, in the University Hospital Donostia, in order to reduce the dose to patients and without prejudice to the required diagnosis. (Author)

Contemporary Australian dose area product levels in the fluoroscopic investigation of paediatric congenital heart disease

International Nuclear Information System (INIS)

Jones, T.; Brennan, P.C.; Mello-Thoms, C.; Ryan, E.

2017-01-01

This study examines radiation dose levels delivered to children from birth to 15 y of age in the investigation of congenital heart disease (CHD) at a major Sydney children's hospital. The aims are to compare values with those derived from similar studies, to provide a template for more consistent dose reporting, to establish local and national diagnostic reference levels and to contribute to the worldwide paediatric dosimetry database. A retrospective review of 1007 paediatric procedural records was undertaken. The cohort consisted of 795 patients over a period from January 2007 to December 2012 who have undergone cardiac catheterisation for the investigation of CHD. The age range included was from the day of birth to 15 y. Archived dose area product (DAP) and fluoroscopy time (FT) readings were retrieved and analysed. The mean, median, 25. and 75. percentile DAP levels were calculated for six specific age groupings. The 75. percentile DAP values for the specific age categories were as follows: 0-30 d-1.9 Gy cm 2 , 1-12 months-2.9 Gy cm 2 , 1-3 y-5.3 Gy cm 2 , 3-5 y-6.2 Gy cm 2 , 5-10 y-7.5 Gy cm 2 and 10-15 y-17.3 Gy cm 2 . These levels were found to be lower than the values reported in comparable overseas studies. Individual year-specific levels were determined, and it is proposed that these are more useful than the common grouping method. The age-specific 75. percentile DAP levels outlined in this study can be used as baseline local diagnostic reference levels. The needs for the standardisation of DAP reporting and for a greater range of age-specific diagnostic reference levels have been highlighted. For the first time, Australian dose values for paediatric cardiac catheterisation are presented. (authors)

Effect of radiation dose level on the detectability of pulmonary nodules in chest tomosynthesis.

Science.gov (United States)

Asplund, Sara A; Johnsson, Åse A; Vikgren, Jenny; Svalkvist, Angelica; Flinck, Agneta; Boijsen, Marianne; Fisichella, Valeria A; Månsson, Lars Gunnar; Båth, Magnus

2014-07-01

To investigate the detectability of pulmonary nodules in chest tomosynthesis at reduced radiation dose levels. Eighty-six patients were included in the study and were examined with tomosynthesis and computed tomography (CT). Artificial noise was added to simulate that the tomosynthesis images were acquired at dose levels corresponding to 12, 32, and 70% of the default setting effective dose (0.12 mSv). Three observers (with >20, >20 and three years of experience) read the tomosynthesis cases for presence of nodules in a free-response receiver operating characteristics (FROC) study. CT served as reference. Differences between dose levels were calculated using the jack-knife alternative FROC (JAFROC) figure of merit (FOM). The JAFROC FOM was 0.45, 0.54, 0.55, and 0.54 for the 12, 32, 70, and 100% dose levels, respectively. The differences in FOM between the 12% dose level and the 32, 70, and 100% dose levels were 0.087 (p = 0.006), 0.099 (p = 0.003), and 0.093 (p = 0.004), respectively. Between higher dose levels, no significant differences were found. A substantial reduction from the default setting dose in chest tomosynthesis may be possible. In the present study, no statistically significant difference in detectability of pulmonary nodules was found when reducing the radiation dose to 32%. • A substantial radiation dose reduction in chest tomosynthesis may be possible. • Pulmonary nodule detectability remained unchanged at 32% of the effective dose. • Tomosynthesis might be performed at the dose of a lateral chest radiograph.

A reference dosimetric system for dose interval of radiotherapy based on alanine/RPE; Um sistema dosimetrico de referencia para o intervalo de doses da radioterapia baseado na alanina/RPE

Energy Technology Data Exchange (ETDEWEB)

Rodrigues Junior, Orlando; Galante, Ocimar L.; Campos, Leticia L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rodrijr@net.ipen.br

2001-07-01

This work describes the development of a reference dosimetric system based on alanine/EPR for radiotherapy dose levels. Currently the IPEN is concluding a similar system for the dose range used for irradiation of products, 10-10{sup 5} Gy. The objective of this work is to present the efforts towards to improve the measure accuracy for doses in the range between 1-10 Gy. This system could be used as reference by radiotherapy services, as much in the quality control of the equipment, as for routine accompaniment of more complex handling where the total doses can reach some grays. The system uses alanine as detector and electronic paramagnetic resonance - EPR as measure technique. To reach accuracy better than 5% mathematical studies on the best optimization of the EPR spectrometer parameters and methods for the handling of the EPR sign are discussed. (author)

Data base of dose coefficients called ecrin-V1-internet reference handbook; Base de donnees de coefficients de dose ecrin-V1-internet manuel de reference

Energy Technology Data Exchange (ETDEWEB)

Perrin, M.L

2003-07-01

The objective of this data base is to dispose on a only computer medium the values of radiation doses allowing to guarantee the tracing and the coherence of radiation doses received by man. These data are usable to evaluate the risks in the frame of studies or expertise. They include the doses coming from external irradiations, internal contamination by inhalation or ingestion and receive by workers or public. The definitions and reference values come from international publications (the list is given). (N.C.)

Radioactivity reference levels in ceramics tiles as building materials for different countries

International Nuclear Information System (INIS)

Ortiz, Josefina; Ballesteros, Luisa; Serradell, Vicente

2008-01-01

Measurements campaigns of ceramic tiles and raw materials used in them, shows that natural radionuclides of uranium ( 238 U) and thorium ( 232 Th) series, together with the radioactive isotope of potassium ( 40 K ), are presents. Uranium series contain radium, which decays to radon ( 222 Rn), an inert gas that can be released from materials and inhaled by individuals. Limits of 226 Ra concentrations are established by different countries in order to control Radon levels (200 Bq.m -3 in European Union). Potassium -40 and others gamma emitters of 226 Ra and 232 Th descendent, can cause an external dose. Therefore, with the purpose that individual doses due to building materials doesn't exceed a certain level recommendations or regulations have been established. A maximum value of 1 mSv.y -1 is recommended in European Union. In practice an easy way to avoid ceramic tiles provide doses to individuals over the reference level is to introduce an index, depending on activities concentrations of 226 Ra, 232 Th and 40 K, defined so that the dose limits due, exclusively, to building materials, will never be exceeded. These limits and indexes present differences between countries. In this paper indexes are compared and differences are discussed. (author)

Evaluation of the dose uniformity for double-plane high dose rate interstitial breast implants with the use of dose reference points and dose non-uniformity ratio

International Nuclear Information System (INIS)

MAjor, T.; Polgar, C.; Somogyi, A.; Nemeth, G.

2000-01-01

This study investigated the influence of dwell time optimizations on dose uniformity characterized by dose values in dose points and dose non-uniformity ratio (DNR) and analyzed which implant parameters have influence on the DNR. Double-plane breast implants with catheters arranged in triangular pattern were used for the calculations. At a typical breast implant, dose values in dose reference points inside the target volume and volumes enclosed by given isodose surfaces were calculated and compared for non-optimized and optimized implants. The same 6-cm treatment length was used for the comparisons. Using different optimizations plots of dose non-uniformity ratio as a function of catheter separation, source step size, number of catheters, length of active sections were drawn and the minimum DNR values were determined. Optimization resulted in less variation in dose values over dose points through the whole volume and in the central plane only compared to the non-optimized case. At implant configurations consisting of seven catheters with 15-mm separation, 5-mm source step size and various active lengths adapted according to the type of optimization, the no optimization, geometrical (volume mode) and dose point (on dose points and geometry) optimization resulted in similar treatment volumes, but an increased high dose volume was observed due to the optimization. The dose non-uniformity ratio always had the minimum at average dose over dose normalization points, defined in the midpoints between the catheters through the implant volume. The minimum value of DNR depended on catheter separation, source step size, active length and number of catheters. The optimization had only a small influence on DNR. In addition to the reference points in the central plane only, dose points positioned in the whole implant volume can be used for evaluating the dose uniformity of interstitial implants. The dose optimization increases not only the dose uniformity within the implant but

Operator dependency of the radiation exposure in cardiac interventions: feasibility of ultra low dose levels

International Nuclear Information System (INIS)

Emre Ozpelit, Mehmet; Ercan, Ertugrul; Pekel, Nihat; Tengiz, Istemihan; Yilmaz, Akar; Ozpelit, Ebru; Ozyurtlu, Ferhat

2017-01-01

Introduction: Mean radiation exposure in invasive cardiology varies greatly between different centres and interventionists. The International Commission on Radiological Protection and the EURATOM Council stipulate that, despite reference values, 'All medical exposure for radiodiagnostic purposes shall be kept as low as reasonably achievable' (ALARA). The purpose of this study is to establish the effects of the routine application of ALARA principles and to determine operator and procedure impact on radiation exposure in interventional cardiology. Materials and methods: A total of 240 consecutive cardiac interventional procedures were analysed. Five operators performed the procedures, two of whom were working in accordance with ALARA principles (Group 1 operators) with the remaining three working in a standard manner (Group 2 operators). Radiation exposure levels of these two groups were compared. Results: Total fluoroscopy time and the number of radiographic runs were similar between groups. However, dose area product and cumulative dose were significantly lower in Group 1 when compared with Group 2. Radiation levels of Group 1 were far below even the reference levels in the literature, thus representing an ultra-low-dose radiation exposure in interventional cardiology. Conclusion: By use of simple radiation reducing techniques, ultra-low-dose radiation exposure is feasible in interventional cardiology. Achievability of such levels depends greatly on operator awareness, desire, knowledge and experience of radiation protection. (authors)

Establishment of Reference Doses for residues of allergenic foods: Report of the VITAL Expert Panel

NARCIS (Netherlands)

Taylor, S.L.; Baumert, J.L.; Kruizinga, A.G.; Remington, B.C.; Crevel, R.W.R.; Brooke-Taylor, S.; Allen, K.J.; Houben, G.

2014-01-01

In 2011, an expert panel was assembled to establish appropriate Reference Doses for allergenic food residues as a part of the VITAL (Voluntary Incidental Trace Allergen Labeling) program of The Allergen Bureau of Australia & New Zealand (ABA). These Reference Doses would guide advisory labeling

Diagnostic reference levels in intraoral dental radiography in Korea

International Nuclear Information System (INIS)

Kim, Eun Kyung; Han, Won Jeong; Choi, Jin Woo; Jung, Yun Hoa; Yoon, Suk Ja; Lee, Jae Seo

2012-01-01

The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 mGycm2 (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 mGycm 2 (DAP). Doses at university dental hospitals were lower than those at dental clinics (p 2 (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

Patient dose measurement and dose reduction in East Anglia (UK)

International Nuclear Information System (INIS)

Wade, J.P.; Goldstone, K.E.; Dendy, P.P.

1995-01-01

At the end of 1990 a programme of patient dose measurements was introduced as part of the quality assurance service already provided for X ray departments throughout the East Anglian Health Region (UK). Thermoluminescence dosemeters (TLDs) were used to measure over 1200 skin entrance surface doses for four common radiographic views in 33 hospitals in both the NHS and private sector. The four views were chosen to cover a wide range of equipment and techniques. The data collected have enabled Regional reference doses to be set which, for all views considered, fall below the National Radiological Protection Board (NRPB) Reference levels. In departments which exceeded reference levels, techniques were reviewed, improvements suggested and doses re-measured, in accordance with the recommended procedure for patient dose audit. A significant finding was that, given appropriate controls, X ray departments in the private sector could achieve the same acceptably low doses as NHS departments. (Author)

Internal Dose Conversion Coefficients of Domestic Reference Animal and Plants for Dose Assessment of Non-human Species

International Nuclear Information System (INIS)

Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho

2009-01-01

Traditionally, radiation protection has been focused on a radiation exposure of human beings. In the international radiation protection community, one of the recent key issues is to establish the methodology for assessing the radiological impact of an ionizing radiation on non-human species for an environmental protection. To assess the radiological impact to non-human species dose conversion coefficients are essential. This paper describes the methodology to calculate the internal dose conversion coefficient for non-human species and presents calculated internal dose conversion coefficients of 25 radionuclides for 8 domestic reference animal and plants

Model for assessing alpha doses for a Reference Japanese Man

International Nuclear Information System (INIS)

Kawamura, Hisao

1993-01-01

In view of the development of the nuclear fuel cycle in this country, it is urgently important to establish dose assessment models and related human and environmental parameters for long-lived radionuclides. In the current program, intake and body content of actinides (Pu, Th, U) and related alpha-emitting nuclides (Ra and daughters) have been studied as well as physiological aspects of Reference Japanese Man as the basic model of man for dosimetry. The ultimate object is to examine applicability of the existing models particularly recommended by the ICRP for workers to members of the public. The result of an interlaboratory intercomparison of 239 Pu + 240 Pu determination including our result was published. Alpha-spectrometric determinations of 226 Ra in bone yielded repesentative bone concentration level in Tokyo and Ra-Ca O.R. (bone-diet) which appear consistent with the literature value for Sapporo and Kyoto by Ohno using a Rn emanation method. Specific effective energies for alpha radiation from 226 Ra and daughters were calculated using the ICRP dosimetric model for bone incorporating masses of source and target organs of Reference Japanese Man. Reference Japanese data including the adult, adolescent, child and infant of both sexes was extensively and intensively studied by Tanaka as part of the activities of the ICRP Task Group on Reference Man Revision. Normal data for the physical measurements, mass and dimension of internal organs and body surfaces and some of the body composition were analysed viewing the nutritional data in the Japanese population. Some of the above works are to be continued. (author)

Studies on the establishment of maximum permissible exposure dose for reference Korean

International Nuclear Information System (INIS)

Kim, Y.J.; Lee, K.S.; Chun, K.C.; Kim, C.B.; Chung, K.H.; Kim, S.L.; Kim, M.J.

1981-01-01

In order to establish the Reference Korean and maximum permissible exposure dose of Reference Korean, for the first year a total of 9,758 males and 7,019 females were surveyed for the height, weight, a body surface area, and a total of 879 individuals of 180 households located in different 30 localities were analyzed for food consumption and a total of radioactive substances (β-ray) contained in food per capita per day. In this report the external and internal exposure dose were also estimated on the basis of data mostly published in other country as well as in Korea in part

Discussion on Implementation of ICRP Recommendations Concerning Reference Levels and Optimisation

International Nuclear Information System (INIS)

2013-02-01

International Commission on Radiological Protection (ICRP) Publication 103, 'The 2007 Recommendations of the International Commission on Radiological Protection', issued in 2007, defines emergency exposure situations as unexpected situations that may require the implementation of urgent protective actions and perhaps longer term protective actions. The ICRP continues to recommend optimisation and the use of reference levels to ensure an adequate degree of protection in regard to exposure to ionising radiation in emergency exposure situations. Reference levels represent the level of dose or risk above which it is judged to be inappropriate to plan to allow exposures to occur and for which protective actions should therefore be planned and optimised. National authorities are responsible for establishing reference levels. The Expert Group on the Implementation of New International Recommendations for Emergency Exposure Situations (EGIRES) performed a survey to analyse the established processes for optimisation of the protection strategy for emergency exposure situations and for practical implementation of the reference level concept in several member states of the Nuclear Energy Agency (NEA). The EGIRES collected information on several national optimisation strategy definitions, on optimisation of protection for different protective actions, and also on optimisation of urgent protective actions. In addition, national criteria for setting reference levels, their use, and relevant processes, including specific triggers and dosimetric quantifies in setting reference levels, are focus points that the EGIRES also evaluated. The analysis of national responses to this 2011 survey shows many differences in the interpretation and application of the established processes and suggests that most countries are still in the early stages of implementing these processes. Since 2011, national authorities have continued their study of the ICRP recommendations to incorporate them into

Local diagnostic reference level based on size-specific dose estimates: Assessment of pediatric abdominal/pelvic computed tomography at a Japanese national children's hospital

Energy Technology Data Exchange (ETDEWEB)

Imai, Rumi; Miyazaki, Osamu; Kurosawa, Hideo; Nosaka, Shunsuke [National Center for Child Health and Development, Department of Radiology, Setagaya-ku, Tokyo (Japan); Horiuchi, Tetsuya [Osaka University, Department of Medical Physics and Engineering, Division of Medical Technology and Science, Course of Health Science, Graduate School of Medicine, Suita, Osaka (Japan)

2015-03-01

A child's body size is not accurately reflected by volume CT dose index (CTDI{sub vol}) and dose-length product (DLP). Size-specific dose estimation (SSDE) was introduced recently as a new index of radiation dose. However, it has not yet been established as a diagnostic reference level (DRL). To calculate the SSDE of abdominal/pelvic CT and compare the SSDE with CTDI{sub vol}. To calculate the DRLs of CTDI{sub vol} and SSDE. Our hypotheses are: SSDE values will be greater than CTDI{sub vol}, and our DRL will be smaller than the known DRLs of other countries. The CTDI{sub vol} and DLP of 117 children who underwent abdominal/pelvic CT were collected retrospectively. The SSDE was calculated from the sum of the lateral and anteroposterior diameters. The relationships between body weight and effective diameter and between effective diameter and CTDI{sub vol}/SSDE were compared. Further, the local DRL was compared with the DRLs of other countries. Body weight and effective diameter and effective diameter and SSDE were positively correlated. In children ages 1, 5 and 10 years, the SSDE is closer to the exposure dose of CTDI{sub vol} for the 16-cm phantom, while in children ages 15 years, the SSDE falls between CTDI{sub vol} for the 16-cm phantom and that for the 32-cm phantom. The local DRL was lower than those of other countries. With SSDE, the radiation dose increased with increasing body weight. Since SSDE takes body size into account, it proved to be a useful indicator for estimating the exposure dose. (orig.)

Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

International Nuclear Information System (INIS)

Endo, Akira; Petoussi-Henss, Nina; Zankl, Maria; Schlattl, Helmut; Bolch, Wesley E.; Eckerman, Keith F.; Hertel, Nolan E.; Hunt, John G.; Pelliccioni, Maurizio; Menzel, Hans-Georg

2014-01-01

This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors. This paper briefly reviews the reference computational phantoms and dose conversion coefficients for external exposures that were published jointly by ICRP and ICRU. Both these publications appeared as a consequence of the ICRP 2007 Recommendations; to implement these recommendations, the ICRP has developed reference computational phantoms representing the adult male and female. These phantoms are used to calculate reference dose conversion coefficients for external and internal sources. Using the reference phantoms and methodology consistent with the 2007 Recommendations, dose conversion coefficients for both effective doses and organ-absorbed doses for various types of idealised external exposures have been calculated. These data sets supersede the existing ICRP/ICRU data sets and expand the particle types and energy ranges. For neutrons, the new effective dose conversion coefficients become smaller compared with those in ICRP74, for energies below hundreds of keV. This is mainly

Reference levels for assays in opened installations of industrial radiography; Niveis de referencia para ensaios em instalacoes abertas de radiografia industrial

Energy Technology Data Exchange (ETDEWEB)

Leocadio, Joao C.; Tauhata, Luiz [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Crispim, Verginia R. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear

2001-07-01

This work had as objectives to analyze the facilities open of industrial x-ray to obtain the distribution of doses in the operators and present proposed for the reference levels. The results of the monitoring revealed an improvement of the radiation protection conditions in the facilities and that the risk of potential exposure was reduced. The advantage of the proposed reference levels is that the supervisors would enlarge the frequency of audits in the facilities opened to accomplish the investigations and interventions.The facilities open with 'bunkers' presented distributions with 95% of the doses below 0,2 mSv and the distributions of the facilities with cordoned area they had 75% of the doses below 0,4 mSv. (author)

Method of evaluation of diagnostics reference levels in computerized tomography; Metodo de avaliacao de niveis de referencia de radiodiagnostico em tomografia computadorizada

Energy Technology Data Exchange (ETDEWEB)

Vega, Walter Flores

1999-04-01

Computerized tomography is a complex technique with several selectable exposition parameters delivering high doses to the patient. In this work it was developed a simple methodology to evaluate diagnostic reference levels in computerized tomography, using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Health Ministry. For evaluation of the MSAD, a dose distribution was obtained through a measured dose profile on the axial axis of a water phantom with thermoluminescence dosemeters, TLD-100, for different exam technique. The MSAD was evaluated hrough two distinct methods. First, it was evaluated by the integration of the dose profile of a single slice and, second, obtained by the integration on central slice of the profile of several slices. The latter is in of accordance with the ionization chamber method, suggesting to be the most practical method of dose evaluation to be applied in the diagnostic reference level assessment routine for CT, using TLDs. (author)

Background and anthropogenic radionuclide derived dose rates to freshwater ecosystem - Nuclear power plant cooling pond - Reference organisms

International Nuclear Information System (INIS)

Nedveckaite, T.; Filistovic, V.; Marciulioniene, D.; Prokoptchuk, N.; Plukiene, R.; Gudelis, A.; Remeikis, V.; Yankovich, T.; Beresford, N.-A.

2011-01-01

The radiological assessment of non-human biota to demonstrate protection is now accepted by a number of international and national bodies. Therefore, it is necessary to develop a scientific basis to assess and evaluate exposure of biota to ionizing radiation. Radionuclides from the Ignalina Nuclear Power Plant (Lithuania) were discharged into Lake Druksiai cooling pond. Additional radionuclide migration and recharge to this lake from a hypothetical near-surface, low-level radioactive waste disposal, to be situated 1.5 km from the lake, had been simulated using RESRAD-OFFSITE code. This paper uses ERICA Integrated Approach with associated tools and databases to compare the radiological dose to freshwater reference organisms. Based on these data, it can be concluded that background dose rates to non-human biota in Lake Druksiai far exceed those attributable to anthropogenic radionuclides. With respect the fishery and corresponding annual committed effective human dose as a result of this fish consumption Lake Druksiai continues to be a high-productivity water body with intensive angling and possible commercial fishing. - Highlights: → Dose rates to the reference organisms are lower than expected from the background radioactivity. → Pelagic fish part of adult human annual committed effective dose would be as small as a few μSv y -1 . → With respect the fishery Lake Druksiai continues to be a high-productivity water body.

Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

Energy Technology Data Exchange (ETDEWEB)

Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-02-15

This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, '9{sup 5}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, {sup 240}Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (muGyd{sup -1} per Bqkg{sup -1}) ranged from 10{sup -6} to 10{sup -2} according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as {sup 238}U, {sup 239}Pu, and {sup 240}Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of {sup 239}Pu, {sup 240}Pu, {sup 238}U, {sup 14}C, {sup 3}H and {sup 99}Tc were independent of the organism

Data base of dose coefficients called ecrin-V1-internet reference handbook

International Nuclear Information System (INIS)

Perrin, M.L.

2003-07-01

The objective of this data base is to dispose on a only computer medium the values of radiation doses allowing to guarantee the tracing and the coherence of radiation doses received by man. These data are usable to evaluate the risks in the frame of studies or expertise. They include the doses coming from external irradiations, internal contamination by inhalation or ingestion and receive by workers or public. The definitions and reference values come from international publications (the list is given). (N.C.)

A study to establish international diagnostic reference levels for paediatric computed tomography

International Nuclear Information System (INIS)

Vassileva, J.; Rehani, M.; Kostova-Lefterova, D.; Al-Naemi, H.M.; Al Suwaidi, J.S.; Arandjic, D.; Bashier, E.H.O.; Kodlulovich Renha, S.; El-Nachef, L.; Aguilar, J.G.; Gershan, V.; Gershkevitsh, E.; Gruppetta, E.; Hustuc, A.; Jauhari, A.; Hassan Kharita, Mohammad; Khelassi-Toutaoui, N.; Khosravi, H.R.; Khoury, H.; Kralik, I.; Mahere, S.; Mazuoliene, J.; Mora, P.; Muhogora, W.; Muthuvelu, P.; Nikodemova, D.; Novak, L.; Pallewatte, A.; Pekarovic, D.; Shaaban, M.; Shelly, E.; Stepanyan, K.; Thelsy, N.; Visrutaratna, P.; Zaman, A.

2015-01-01

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol ) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDI w , CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75. percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided. (authors)

The true bladder dose: on average thrice higher than the ICRU reference

International Nuclear Information System (INIS)

Barillot, I.; Horiot, J.C.; Maingon, P.; Bone-Lepinoy, M.C.; D'Hombres, A.; Comte, J.; Delignette, A.; Feutray, S.; Vaillant, D.

1996-01-01

The aim of this study is to compare ICRU dose to doses at the bladder base located from ultrasonography measurements. Since 1990, the dose delivered to the bladder during utero-vaginal brachytherapy was systematically calculated at 3 or 4 points representative of bladder base determined with ultrasonography. The ICRU Reference Dose (IRD) from films, the Maximum Dose (Dmax), the Mean Dose (Dmean) representative of the dose received by a large area of bladder mucosa, the Reference Dose Rate (RDR) and the Mean Dose Rate (MDR) were recorded. Material: from 1990 to 1994, 198 measurements were performed in 152 patients. 98 patients were treated for cervix carcinomas, 54 for endometrial carcinomas. Methods: Bladder complications were classified using French Italian Syllabus. The influence of doses and dose rates on complications were tested using non parametric t test. Results: On average IRD is 21 Gy +/- 12 Gy, Dmax is 51Gy +/- 21Gy, Dmean is 40 Gy +/16 Gy. On average Dmax is thrice higher than IRD and Dmean twice higher than IRD. The same results are obtained for cervix and endometrium. Comparisons on dose rates were also performed: MDR is on average twice higher than RDR (RDR 48 cGy/h vs MDR 88 cGy/h). The five observed complications consist of incontinence only (3 G1, 1G2, 1G3). They are only statistically correlated with RDR p=0.01 (46 cGy/h in patients without complications vs 74 cGy/h in patients with complications). However the full responsibility of RT remains doubtful and should be shared with surgery in all cases. In summary: Bladder mucosa seems to tolerate well much higher doses than previous recorded without increased risk of severe sequelae. However this finding is probably explained by our efforts to spare most of bladder mucosa by 1 deg. ) customised external irradiation therapy (4 fields, full bladder) 2 deg. ) reproduction of physiologic bladder filling during brachytherapy by intermittent clamping of the Foley catheter

Comparison of Hemoglobin Levels Before and After Hemodialysis and Their Effects on Erythropoietin Dosing and Cost

OpenAIRE

Sagheb; Fallahzadeh; Moaref; Fallahzadeh; Dormanesh

2016-01-01

Background Hemoglobin levels measured after hemodialysis, as compared to hemoglobin levels measured before hemodialysis, are suggested to be a more accurate reflection of the hemoglobin levels between hemodialysis sessions, and to be a better reference point for adjusting erythropoietin dosing. Objectives The aim of this study was to compare the hemoglobin levels before and after hemodialysis, to calculate the required erythropoie...

Bioequivalence of fixed-dose combination RIN®-150 to each reference drug in loose combination.

Science.gov (United States)

Wang, H F; Wang, R; O'Gorman, M; Crownover, P; Damle, B

2015-03-01

RIN(®)-150 is a fixed-dose combination (FDC) tablet containing rifampicin (RMP, 150 mg) and isoniazid (INH, 75 mg) developed for the treatment of tuberculosis. This study was conducted at a single center: the Pfizer Clinical Research Unit in Singapore. To demonstrate bioequivalence of each drug component between RIN-150 and individual products in a loose combination. This was a randomized, open-label, single-dose, two-way crossover study. Subjects received single doses of RIN-150 or two individual reference products under fasting conditions in a crossover fashion, with at least 7 days washout between doses. The primary measures for comparison were peak plasma concentration (Cmax) and the area under plasma concentration-time curve (AUC). Of 28 subjects enrolled, 26 completed the study. The adjusted geometric mean ratios of Cmax and AUClast between the FDC and single-drug references and 90% confidence intervals were respectively 91.63% (90%CI 83.13-101.01) and 95.45% (90%CI 92.07-98.94) for RMP, and 107.58% (90%CI 96.07-120.47) and 103.45% (90%CI 99.33-107.75) for INH. Both formulations were generally well tolerated in this study. The RIN-150 FDC tablet formulation is bioequivalent to the two single-drug references for RMP and INH at equivalent doses.

The US EPA reference dose for methylmercury: sources of uncertainty

International Nuclear Information System (INIS)

Rice, D.C.

2004-01-01

The US Environmental Protection Agency (EPA) derived a reference dose for methylmercury in 2001, based on an extensive analysis by the National Research Council (NRC) of the National Academy of Sciences. The NRC performed benchmark dose analysis on a number of endpoints from three longitudinal prospective studies: the Seychelles Islands, the Faroe Islands, and the New Zealand studies. Adverse effects were reported in the latter two studies, but not in the Seychelles study. The NRC also performed an integrative analysis of all three studies. Dose conversion from cord blood or maternal hair mercury concentration was performed by EPA using a one-compartment pharmacokinetic model. A total uncertainty factor of 10 was applied for intrahuman pharmacokinetic and pharmacodynamic variability. There are numerous decisions made by the NRC/EPA that could greatly affect the value of the reference dose (RfD). Some of these include the choice of a linear model for the relationship between mercury body burden and neuropsychological performance, the choice of values of P 0 and the benchmark response, the use of the 'critical study/critical endpoint' approach in the interpretation of the maternal body burden that corresponds to the RfD, the use of central tendencies in a one-compartment pharmacokinetic model rather than the inclusion of the distributions of variables for the population of reproductive-age women, the assumption of unity for the ratio of fetal cord blood to maternal blood methylmercury concentrations, the choice of a total of 10 as an uncertainty factor, and the lack of dose-response analysis for other health effects such as cardiovascular disease. In addition, it may be argued that derivation of a RfD for methylmercury is inappropriate, given that there does not appear to be a threshold for adverse neuropsychological effects based on available data

Relevance of biotic pathways to the long-term regulation of nuclear-waste disposal. Topical report on reference western arid low-level sites

International Nuclear Information System (INIS)

McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

1982-10-01

The purpose of the work reported here was to develop an order of magnitude estimate for the potential dose to man resulting from biotic transport mechanisms at a reference western arid low-level waste site. A description of the reference site is presented that includes the waste inventories, site characteristics and biological communities. Parameter values for biotic transport processes are based on data reported in current literature. Transport and exposure scenarios are developed for assessing biotic transport during 100 years following site closure. Calculations of radionuclide decay and waste container decomposition are made to estimate the quantities available for biotic transport. Dose to a man occupying the reference site following the 100 years of biotic transport are calculated. These dose estimates are compared to dose estimates for the intruder-agricultural scenario reported in the DEIS for 10 CFR 61 (NRC). Dose to man estimates as a result of biotic transport are estimated to be of the same order of magnitude as the dose resulting from the more commonly evaluated human intrusion scenario. The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by the findings presented in this report. These results indicate that biotic transport has the potential to influence low-level waste site performance. Through biotic transport, radionuclides may be moved to locations where they can enter exposure pathways to man

Reference levels in PTCA as a function of procedure complexity

International Nuclear Information System (INIS)

Peterzol, A.; Quai, E.; Padovani, R.; Bernardi, G.; Kotre, C. J.; Dowling, A.

2005-01-01

The multicentre assessment of a procedure complexity index (CI) for the introduction of reference levels (RLs) in percutaneous transluminal coronary angio-plasties (PTCA) is presented here. PTCAs were investigated based on methodology proposed by Bernardi et al. Multiple linear stepwise regression analysis, including clinical, anatomical and technical factors, was performed to obtain fluoroscopy time predictors. Based on these regression coefficients, a scoring system was defined and CI obtained. CI was used to classify dose values into three groups: low, medium and high complexity procedures, since there was good correlation (r = 0.41; P 2 , and 12, 20 and 27 min for fluoroscopy time, for the three CI groups. (authors)

Eye lens dosimetry in interventional cardiology: Results of staff dose measurements and link to patient dose levels

International Nuclear Information System (INIS)

Antic, V.; Ciraj-Bjelac, O.; Rehani, M.; Aleksandric, S.; Arandjic, D.; Ostojic, M.

2013-01-01

Workers involved in interventional cardiology procedures receive high eye lens dose if protection is not used. Currently, there is no suitable method for routine use for the measurement of eye dose. Since most angiography machines are equipped with suitable patient dosemeters, deriving factors linking staff eye doses to the patient doses can be helpful. In this study the patient kerma-area product, cumulative dose at an interventional reference point and eye dose in terms of Hp(3) of the cardiologists, nurses and radiographers for interventional cardiology procedures have been measured. Correlations between the patient dose and the staff eye dose were obtained. The mean eye dose was 121 mSv for the first operator, 33 mSv for the second operator/nurse and 12 mSv for radiographer. Normalised eye lens doses per unit kerma-area product were 0.94 mSv Gy -1 cm -2 for the first operator, 0.33 mSv Gy -1 cm -2 for the second operator/nurse and 0.16 mSv Gy -1 cm -2 for radiographers. Statistical analysis indicated that there is a weak but significant (p < 0.01) correlation between the eye dose and the kerma-area product for all three staff categories. These values are based on a local practice and may provide useful reference for other studies for validation and for wider utilisation in assessing the eye dose using patient dose values. (authors)

Relevance of biotic pathways to the long-term regulation of nuclear waste disposal. Topical report on reference eastern humid low-level sites

International Nuclear Information System (INIS)

McKenzie, D.H.; Cadwell, L.L.; Eberhardt, L.E.; Kennedy, W.E. Jr.; Peloquin, R.A.; Simmons, M.A.

1983-01-01

The purpose of the work reported here was to develop an order-of-magnitude estimate for the potential dose to man resulting from biotic transport mechanisms at a humid reference low-level waste site in the eastern US. A description of the reference site is presented that includes the waste inventories, site characteristics and biological communites. Parameter values for biotic transport processes are based on data reported in current literature. Transport and exposure scenarios are developed for assessing biotic transport during 500 years following site closure. Calculations of radionuclide decay and waste container decomposition are made to estimate the quantities available for biotic transport. Doses to man are calculated for the biological transport of radionucludes at the reference site after loss of institutional control. These dose estimates are compared to dose estimates we calculated for the intruder-agricultural scenarios reported in the DEIS for 10 CFR 61 (NRC). Dose to man estimates as a result of cumulative biotic transport are calculated to be of the same order-of-magnitude as the dose resulting from the more commonly evaluated human intrusion scenario. The reported lack of potential importance of biotic transport at low-level waste sites in earlier assessment studies is not confirmed by findings presented in this report. Through biotic transport, radionuclides can be moved to locations where they can enter exposure pathways to man

Dose coefficients for public exposition; Coeficientes de dose para exposicao ao publico

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This Regulation refers to the requirements of the Regulation CNEN-NN.3.01 'Basic Guidelines for Radiation Protection', to be applied to the dose calculus with the objective of verification according to the limits and restrictions of dose and reference levels of the public individuals, expressed in its section 5

Process control and dosimetry applied to establish a relation between reference dose measurements and actual dose distribution

Energy Technology Data Exchange (ETDEWEB)

Ehlerman, D A.E. [Institute of Process Engineering, Federal Research Centre for Nutrition, Karlsruhe (Germany)

2001-03-01

The availability of the first commercial dose level indicator prompted attempts to verify radiation absorbed dose to items under quarantine control (e.g. for insect disinfestation) by some indicator attached to these items. Samples of the new commercial dose level indicators were tested for their metrological properties using gamma and electron irradiation. The devices are suitable for the intended purpose and the subjective judgement whether the threshold dose was surpassed is possible in a reliable manner. The subjective judgements are completely backed by the instrumental results. Consequently, a prototype reader was developed; first tests were successful. The value of dose level indicators and the implications of its use for food or quarantine inspection depends on a link between dose measured (indicated) at the position of such indicator and the characteristic parameters of the frequency distribution of dose throughout the product load i.e. a box or a container or a whole batch of multiple units. Therefore, studies into variability and statistical properties of dose distributions obtained under a range of commercial situations were undertaken. Gamma processing at a commercial multipurpose contract irradiator, electron processing and bremsstrahlung applications at a largescale research facility were included; products were apples, potatoes, wheat, maize, pistachio. Studies revealed that still more detailed information on irradiation geometries are needed in order to render meaningful information from dose label indicators. (author)

Process control and dosimetry applied to establish a relation between reference dose measurements and actual dose distribution

International Nuclear Information System (INIS)

Ehlerman, D.A.E.

2001-01-01

The availability of the first commercial dose level indicator prompted attempts to verify radiation absorbed dose to items under quarantine control (e.g. for insect disinfestation) by some indicator attached to these items. Samples of the new commercial dose level indicators were tested for their metrological properties using gamma and electron irradiation. The devices are suitable for the intended purpose and the subjective judgement whether the threshold dose was surpassed is possible in a reliable manner. The subjective judgements are completely backed by the instrumental results. Consequently, a prototype reader was developed; first tests were successful. The value of dose level indicators and the implications of its use for food or quarantine inspection depends on a link between dose measured (indicated) at the position of such indicator and the characteristic parameters of the frequency distribution of dose throughout the product load i.e. a box or a container or a whole batch of multiple units. Therefore, studies into variability and statistical properties of dose distributions obtained under a range of commercial situations were undertaken. Gamma processing at a commercial multipurpose contract irradiator, electron processing and bremsstrahlung applications at a largescale research facility were included; products were apples, potatoes, wheat, maize, pistachio. Studies revealed that still more detailed information on irradiation geometries are needed in order to render meaningful information from dose label indicators. (author)

An approach to local diagnostic reference levels (DRL's) in the context of national and international DRL's

International Nuclear Information System (INIS)

Rogers, A.T.

2001-01-01

In recent years there has been a greater focus on the management of patient doses. This effort has been driven by the realisation of both the increasing magnitude of patient doses and their variation both intra- and inter-nationally. Legislators and guidance-issuing bodies have developed the idea of 'Diagnostic Reference Levels' (DRL's). In particular, the European Union, in their Council Directive 97/43/Euratom, required Member States to develop DRL's. The UK Government, when consolidating this EU Directive into UK legislation, extended the concept of DRL's from a national to an employer level. However, the methodologies used for development of national and international DRL's do not translate to a local level and hence a new approach is required. This paper describes one particular approach made by a UK hospital to introduce 'Local DRL's' in such a manner as to aid the optimisation process. This approach utilises a dose index, based on the local patient population, which is monitored for trends. Any trend in patient dose triggers an investigation linked to the clinical audit system within the Clinical Radiology Department. It is the audit cycle that ensures a continuing move towards an optimised situation. Additional triggers may be employed such as large patient dose variations. (author)

Patient Dose During Carotid Artery Stenting With Embolic-Protection Devices: Evaluation With Radiochromic Films and Related Diagnostic Reference Levels According to Factors Influencing the Procedure

International Nuclear Information System (INIS)

D’Ercole, Loredana; Quaretti, Pietro; Cionfoli, Nicola; Klersy, Catherine; Bocchiola, Milena; Rodolico, Giuseppe; Azzaretti, Andrea; Lisciandro, Francesco; Cascella, Tommaso; Zappoli Thyrion, Federico

2013-01-01

To measure the maximum entrance skin dose (MESD) on patients undergoing carotid artery stenting (CAS) using embolic-protection devices, to analyze the dependence of dose and exposure parameters on anatomical, clinical, and technical factors affecting the procedure complexity, to obtain some local diagnostic reference levels (DRLs), and to evaluate whether overcoming DRLs is related to procedure complexity. MESD were evaluated with radiochromic films in 31 patients (mean age 72 ± 7 years). Five of 33 (15 %) procedures used proximal EPD, and 28 of 33 (85 %) procedures used distal EPD. Local DRLs were derived from the recorded exposure parameters in 93 patients (65 men and 28 women, mean age 73 ± 9 years) undergoing 96 CAS with proximal (33 %) or distal (67 %) EPD. Four bilateral lesions were included. MESD values (mean 0.96 ± 0.42 Gy) were FR ) were 269 Gy cm 2 , 28 minutes, and 251, respectively. Only simultaneous bilateral treatment was associated with KAP (odds ratio [OR] 10.14, 95 % confidence interval [CI] 1–102.7, p FR overexposures (OR 10.8, 95 % CI 1.1–109.5, p FR overexposure (OR 2.8, 95 % CI 1.1–7.4, p = 0.040). At multivariable analysis, stenosis ≥ 90 % (OR 2.8, 95 % CI 1.1–7.4, p = 0.040) and bilateral treatment (OR 10.8, 95 % CI 1.1–109.5, p = 0.027) were associated with overexposure for two or more parameters. Skin doses are not problematic in CAS with EPD because these procedures rarely lead to doses >2 Gy.

Fluoroscopy-guided insertion of nasojejunal tubes in children - setting local diagnostic reference levels

International Nuclear Information System (INIS)

Vitta, Lavanya; Raghavan, Ashok; Sprigg, Alan; Morrell, Rachel

2009-01-01

Little is known about the radiation burden from fluoroscopy-guided insertions of nasojejunal tubes (NJTs) in children. There are no recommended or published standards of diagnostic reference levels (DRLs) available. To establish reference dose area product (DAP) levels for the fluoroscopy-guided insertion of nasojejunal tubes as a basis for setting DRLs for children. In addition, we wanted to assess our local practice and determine the success and complication rates associated with this procedure. Children who had NJT insertion procedures were identified retrospectively from the fluoroscopy database. The age of the child at the time of the procedure, DAP, screening time, outcome of the procedure, and any complications were recorded for each procedure. As the radiation dose depends on the size of the child, the children were assigned to three different age groups. The sample size, mean, median and third-quartile DAPs were calculated for each group. The third-quartile values were used to establish the DRLs. Of 186 procedures performed, 172 were successful on the first attempt. These were performed in a total of 43 children with 60% having multiple insertions over time. The third-quartile DAPs were as follows for each age group: 0-12 months, 2.6 cGy cm 2 ; 1-7 years, 2.45 cGy cm 2 ; >8 years, 14.6 cGy cm 2 . High DAP readings were obtained in the 0-12 months (n = 4) and >8 years (n = 2) age groups. No immediate complications were recorded. Fluoroscopy-guided insertion of NJTs is a highly successful procedure in a selected population of children and is associated with a low complication rate. The radiation dose per procedure is relatively low. (orig.)

Fluoroscopy in paediatric fractures - Setting a local diagnostic reference level

International Nuclear Information System (INIS)

Pillai, A.; McAuley, A.; McMurray, K.; Jain, M.

2006-01-01

Background: The ionizing radiations (Medical Exposure) Regulation 2000 has made it mandatory to establish diagnostic reference levels (DRLs) for all typical radiological examinations. Objectives: We attempt to provide dose data for some common fluoroscopic procedures used in orthopaedic trauma that may be used as the basis for setting DRLs for paediatric patients. Materials and methods: The dose area product (DAP) in 865 paediatric trauma examinations was analysed. Median DAP values and screening times for each procedure type along with quartile values for each range are presented. Results: In the upper limb, elbow examinations had maximum exposure with a median DAP value of 1.21 cGy cm 2 . Median DAP values for forearm and wrist examinations were 0.708 and 0.538 cGy cm 2 , respectively. In lower limb, tibia and fibula examinations had a median DAP value of 3.23 cGy cm 2 followed by ankle examinations with a median DAP of 3.10 cGy cm 2 . The rounded third quartile DAP value for each distribution can be used as a provisional DRL for the specific procedure type. (authors)

Reference dosimetry of proton pencil beams based on dose-area product: a proof of concept.

Science.gov (United States)

Gomà, Carles; Safai, Sairos; Vörös, Sándor

2017-06-21

This paper describes a novel approach to the reference dosimetry of proton pencil beams based on dose-area product ([Formula: see text]). It depicts the calibration of a large-diameter plane-parallel ionization chamber in terms of dose-area product in a 60 Co beam, the Monte Carlo calculation of beam quality correction factors-in terms of dose-area product-in proton beams, the Monte Carlo calculation of nuclear halo correction factors, and the experimental determination of [Formula: see text] of a single proton pencil beam. This new approach to reference dosimetry proves to be feasible, as it yields [Formula: see text] values in agreement with the standard and well-established approach of determining the absorbed dose to water at the centre of a broad homogeneous field generated by the superposition of regularly-spaced proton pencil beams.

Reference beta radiations for calibrating dosemeters and dose ratemeters and for determining their response as a function of beta radiation energy. 1. ed.

International Nuclear Information System (INIS)

1984-01-01

This International Standard specifies the requirements for reference beta radiations produced by radionuclide sources to be used for the calibration of protection level dosemeters and dose ratemeters, and for the determination of their response as a function of beta energy. It gives the characteristics of radionuclides which have been used to produce reference beta radiations, gives examples of suitable source constructions and describes methods for the measurement of the residual maximum beta energy and the absorbed dose rate at a depth of 7 mg·cm -2 in a semi-infinite tissue-equivalent medium. The energy range involved lies between 66 keV and 3.6 MeV and the absorbed dose rates are in the range from about 10 μGy·h -1 (1 mrad·h -1 ) to at least 10 Gy·h -1 (10 3 rad·h -1 ). This International Standard proposes two series of beta reference radiations from which the radiation necessary for determining the characteristics (calibration and energy response) of an instrument shall be selected. Series 1 reference radiations are produced by radionuclide sources used with beam flattening filters designed to give uniform dose rates over a large area at a specific distance. The proposed sources of 90 Sr+ 90 Y, 204 TI and 147 Pm produce maximum dose rates of approximately 5mGy·h -1 (0.5 rad·h -1 ). Series 2 reference radiations are produced without the use of beam flattening filters which allows a range of source-to-calibration plane distances to be used. Close to the sources only relatively small areas of uniform dose rate are produced but this Series has the advantage of extending the energy and dose rate ranges beyond those of Series 1. The radionuclides used are those of Series 1 with the addition of the radionuclides 14 C and 106 Ru+ 106 Rh; these sources produce dose rates of up to 10 Gy·h -1 (10 3 rad·h -1 )

Epidemiological surveys on the effects of low-level radiation dose: a comparative assessment

International Nuclear Information System (INIS)

Rose, K.S.B.

1988-01-01

In this report, the health effects of low-level doses of radiation are considered by reference to published epidemiological surveys. The work was carried out with three objectives in mind: 1. to provide a comprehensive and critical review of the subject; 2. to seek consistent indications of particular health effects by collating results and comparing with those from surveys at moderate-level doses; 3. to provide an authoritative view on the epidemiology of low-level radiation-induced health effects. Vol E (DRAFT A) is appended and contains group collation tables. Epidemiological surveys can be conveniently divided into four classes (A, B, C, D) according to the phase of life when irradiation occurs or the effect is diagnosed. The first of the classes (A) is addressed here; this class is concerned with possible effects arising from radiation received by a parent before conception. Possible effects of preconception irradiation were identified under four broad groupings. These are Down's syndrome, ''Indicators of Reproductive Damage'' (mainly Primary Sterility, Congenital Abnormalities, Sex Ratio, Fetal Mortality, Infant Mortality), Childhood Malignancies, and Chromosomal Changes in Abortuses. Information about each survey, and comparisons with results from moderate-level dose surveys, are contained in synopses that are set out in the Appendix. (author)

Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

Energy Technology Data Exchange (ETDEWEB)

Burns, R.E. Jr.; O`Brien, J.M. Jr. [Atlan-Tech, Rosewll, GA (United States)

1993-12-31

Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison.

Factors affecting quality for beta dose rate measurements using ISO 6980 series I reference sources

International Nuclear Information System (INIS)

Burns, R.E. Jr.; O'Brien, J.M. Jr.

1993-01-01

Atlan-Tech, Inc. has performed several calibrations of ISO 6980 Series 1 reference beta sources over the past two to three years. There were many problems encountered in attempting to compare the results of these calibrations with those from other laboratories, indicating the need for more standardization in the methodology employed for the measurement of the absorbed dose rate from ISO 6980 Series 1 reference beta sources. This document describes some of the problems encountered in attempting to intercompare results of beta dose-rate measurements. It proposes some solutions in an attempt to open a dialogue among facilities using reference beta standards for the purpose of promoting better measurement quality assurance through data intercomparison

Radiation doses to patients from x-ray examinations - development from 2005 to 2008

International Nuclear Information System (INIS)

Leitz, Wolfram; Almen, Anja

2010-04-01

Data has been compiled and analyzed and compared with the earlier reports. Radiation doses were tested for possible links with various parameters (eg type of x-ray equipment, image recording systems, different technique factors). In conventional x-ray examinations radiation doses were, for equipment with direct digital image receivers, in average 30% lower than for those with photo plates. Mammography doses were, with one exception, the same for all types of equipment and video receivers. The CT-examinations had a small trend for higher doses for new equipment as compared to earlier. Use of exposure automation did not affect radiation doses. Compared with 2006, the doses of conventional surveys decreased by an average of 21%. One third of this dose reduction can be attributed the introduction of direct digital system whose use grew by about 30%. Most of the dose reduction can be attributed to the actions carried out to lower the dose of the reference level. Doses for the CT scan showed only a weak downwards trend. Mammography Doses decreased by an average of just over 10% a large part dependent on increased number of Sectra equipment. The system of diagnostic reference levels have again shown to have positive influence on the radiation level at the x-ray examinations, this is most pronounced for conventional radiography. There is still a large potential for dose reduction, and a measure to achieve this is to reduce the current reference levels. Very few diagnostic Standard doses are higher than the reference level. A reduction of the reference levels corresponding to the third quartile of dose distribution could lead further dose decrease of 10-20%. The corresponding reduction in dose should be done also for the DT and mammograms when lowering the reference level, there are few standard doses higher than the current reference levels

External doses from radioactive fallout. Dosimetry and levels

International Nuclear Information System (INIS)

Woehni, T.

1995-01-01

The design, manufacture and calibration of a TL-based dosemeter for measurement of low level external photon radiation are presented. The dosemeter is based on CaF 2 with 2 mm brass filter for energy compensation. It is able to resolve a 8% dose increase relative to natural background radiation. With this dosemeter external dose measurements were made in 6 villages in a heavily contaminated region in Russia (Chernobyl fallout), in order to assess external doses to the population. The results were analyzed in the light of additional existing information on radioactive deposition, social habits, decontamination measures and other influencing technical and physical factors. The observed dose values were lower than theoretical estimates of external doses based on published values for external dose levels relative to the level of contamination. 84 refs., 7 figs., 5 tabs

External doses from radioactive fallout. Dosimetry and levels

Energy Technology Data Exchange (ETDEWEB)

Woehni, T

1996-12-31

The design, manufacture and calibration of a TL-based dosemeter for measurement of low level external photon radiation are presented. The dosemeter is based on CaF{sub 2} with 2 mm brass filter for energy compensation. It is able to resolve a 8% dose increase relative to natural background radiation. With this dosemeter external dose measurements were made in 6 villages in a heavily contaminated region in Russia (Chernobyl fallout), in order to assess external doses to the population. The results were analyzed in the light of additional existing information on radioactive deposition, social habits, decontamination measures and other influencing technical and physical factors. The observed dose values were lower than theoretical estimates of external doses based on published values for external dose levels relative to the level of contamination. 84 refs., 7 figs., 5 tabs.

External doses from radioactive fallout. Dosimetry and levels

Energy Technology Data Exchange (ETDEWEB)

Woehni, T.

1995-12-31

The design, manufacture and calibration of a TL-based dosemeter for measurement of low level external photon radiation are presented. The dosemeter is based on CaF{sub 2} with 2 mm brass filter for energy compensation. It is able to resolve a 8% dose increase relative to natural background radiation. With this dosemeter external dose measurements were made in 6 villages in a heavily contaminated region in Russia (Chernobyl fallout), in order to assess external doses to the population. The results were analyzed in the light of additional existing information on radioactive deposition, social habits, decontamination measures and other influencing technical and physical factors. The observed dose values were lower than theoretical estimates of external doses based on published values for external dose levels relative to the level of contamination. 84 refs., 7 figs., 5 tabs.

A review of data on the effects of low and low dose-rate radiation with special reference to the dose limit problem

International Nuclear Information System (INIS)

Matsudaira, Hiromichi

1977-01-01

This is a review of data pertaining to detection and quantification of the effects after exposure to low LET radiations delivered at low and low dose-rate, i.e., at a level of maximum permissible dose for the radiation workers, on experimental materials ranging from plant to rodents and on some human populations. Irradiation at a dose of a few rad is reported to induce mutation or malignant transformation in some selected model systems, with a linear dose-effect relationship. Moreover, the incidence of the chromosome aberrations in spermatocytes is reported to be elevated in the scorpiones (Tityus bahiensis) collected in a region of high natural background radiations (several rem/year). An increase in the incidence of childhood malignancies is reported among children exposed in utero to diagnostic X-rays. Appreciable increase in the incidence of genetic diseases due possibly to chromosome aberrations is also reported among population living in a region of high natural background radiations. Points are raised and discussed as to the interpretation and particularly application of these data to the estimation of somatic and genetic risks of human population from man-made radiations. Recent attempts of risk-benefit analysis with populations subjected to mass X-ray examination of the chest and stomac are referred to. Since we are unaware of the actual injuries due to the exposure even at the level of radiation workers (5 rem/year), it is out of the capacity of a biologist to afford the basis for the decision of limiting the exposure of general population due to the light water reactor operation to 5 mrem/year. (auth.)

Evaluation of dose conversion coefficients for external exposure using Taiwanese reference man and woman

International Nuclear Information System (INIS)

Chang, S.J.; Hung, S.Y.; Liu, Y.L.; Jiang, S.H.; Wu, J.

2015-01-01

Reference man has been widely used for external and internal dose evaluation of radiation protection. The parameters of the mathematical model of organs suggested by the International Commission of Radiological Protection (ICRP) are adopted from the average data of Caucasians. However, the organ masses of Asians are significantly different from the data of Caucasians, leading to potentially dosimetric errors. In this study, a total of 40 volunteers whose heights and weights corresponded to the statistical average of Taiwanese adults were recruited. Magnetic resonance imaging was performed, and T2-weighted images were acquired. The Taiwanese reference man and woman were constructed according to the measured organ masses. The dose conversion coefficients (DCFs) for anterior-posterior (AP), posterior-anterior (PA), right lateral (RLAT) and left lateral (LLAT) irradiation geometries were simulated. For the Taiwanese reference man, the average differences of the DCFs compared with the results of ICRP-74 were 7.6, 5.1 and 11.1 % for 0.1, 1 and 10 MeV photons irradiated in the AP direction. The maximum difference reached 51.7 % for the testes irradiated by 10 MeV photons. The size of the trunk, the volume and the geometric position of organs can cause a significant impact on the DCFs for external exposure of radiation. The constructed Taiwanese reference man and woman can be used in radiation protection to increase the accuracy of dose evaluation for the Taiwanese population. (authors)

Using Population Dose to Evaluate Community-level Health Initiatives.

Science.gov (United States)

Harner, Lisa T; Kuo, Elena S; Cheadle, Allen; Rauzon, Suzanne; Schwartz, Pamela M; Parnell, Barbara; Kelly, Cheryl; Solomon, Loel

2018-05-01

Successful community-level health initiatives require implementing an effective portfolio of strategies and understanding their impact on population health. These factors are complicated by the heterogeneity of overlapping multicomponent strategies and availability of population-level data that align with the initiatives. To address these complexities, the population dose methodology was developed for planning and evaluating multicomponent community initiatives. Building on the population dose methodology previously developed, this paper operationalizes dose estimates of one initiative targeting youth physical activity as part of the Kaiser Permanente Community Health Initiative, a multicomponent community-level obesity prevention initiative. The technical details needed to operationalize the population dose method are explained, and the use of population dose as an interim proxy for population-level survey data is introduced. The alignment of the estimated impact from strategy-level data analysis using the dose methodology and the data from the population-level survey suggest that dose is useful for conducting real-time evaluation of multiple heterogeneous strategies, and as a viable proxy for existing population-level surveys when robust strategy-level evaluation data are collected. This article is part of a supplement entitled Building Thriving Communities Through Comprehensive Community Health Initiatives, which is sponsored by Kaiser Permanente, Community Health. Copyright © 2018 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Radiation safety concerns and diagnostic reference levels for computed tomography scanners in Tamil Nadu

International Nuclear Information System (INIS)

Livingstone, Roshan S.; Dinakaran, Paul M.

2011-01-01

Radiation safety in computed tomography (CT) scanners is of concern due its widespread use in the field of radiological imaging. This study intends to evaluate radiation doses imparted to patients undergoing thorax, abdomen and pelvic CT examinations and formulate regional diagnostic reference levels (DRL) in Tamil Nadu, South India. In-site CT dose measurement was performed in 127 CT scanners in Tamil Nadu for a period of 2 years as a part of the Atomic Energy Regulatory Board (AERB)-funded project. Out of the 127 CT scanners,13 were conventional; 53 single-slice helical scanners (SSHS); 44 multislice CT (MSCT) scanners; and 17 refurbished scanners. CT dose index (CTDI) was measured using a 32-cm polymethyl methacrylate (PMMA)-body phantom in each CT scanner. Dose length product (DLP) for different anatomical regions was generated using CTDI values. The regional DRLs for thorax, abdomen and pelvis examinations were 557, 521 and 294 mGy cm, respectively. The mean effective dose was estimated using the DLP values and was found to be 8.04, 6.69 and 4.79 mSv for thorax, abdomen and pelvic CT examinations, respectively. The establishment of DRLs in this study is the first step towards optimization of CT doses in the Indian context. (author)

TH-A-9A-01: Active Optical Flow Model: Predicting Voxel-Level Dose Prediction in Spine SBRT

Energy Technology Data Exchange (ETDEWEB)

Liu, J; Wu, Q.J.; Yin, F; Kirkpatrick, J; Cabrera, A [Duke University Medical Center, Durham, NC (United States); Ge, Y [University of North Carolina at Charlotte, Charlotte, NC (United States)

2014-06-15

Purpose: To predict voxel-level dose distribution and enable effective evaluation of cord dose sparing in spine SBRT. Methods: We present an active optical flow model (AOFM) to statistically describe cord dose variations and train a predictive model to represent correlations between AOFM and PTV contours. Thirty clinically accepted spine SBRT plans are evenly divided into training and testing datasets. The development of predictive model consists of 1) collecting a sequence of dose maps including PTV and OAR (spinal cord) as well as a set of associated PTV contours adjacent to OAR from the training dataset, 2) classifying data into five groups based on PTV's locations relative to OAR, two “Top”s, “Left”, “Right”, and “Bottom”, 3) randomly selecting a dose map as the reference in each group and applying rigid registration and optical flow deformation to match all other maps to the reference, 4) building AOFM by importing optical flow vectors and dose values into the principal component analysis (PCA), 5) applying another PCA to features of PTV and OAR contours to generate an active shape model (ASM), and 6) computing a linear regression model of correlations between AOFM and ASM.When predicting dose distribution of a new case in the testing dataset, the PTV is first assigned to a group based on its contour characteristics. Contour features are then transformed into ASM's principal coordinates of the selected group. Finally, voxel-level dose distribution is determined by mapping from the ASM space to the AOFM space using the predictive model. Results: The DVHs predicted by the AOFM-based model and those in clinical plans are comparable in training and testing datasets. At 2% volume the dose difference between predicted and clinical plans is 4.2±4.4% and 3.3±3.5% in the training and testing datasets, respectively. Conclusion: The AOFM is effective in predicting voxel-level dose distribution for spine SBRT. Partially supported by NIH

TH-A-9A-01: Active Optical Flow Model: Predicting Voxel-Level Dose Prediction in Spine SBRT

International Nuclear Information System (INIS)

Liu, J; Wu, Q.J.; Yin, F; Kirkpatrick, J; Cabrera, A; Ge, Y

2014-01-01

Purpose: To predict voxel-level dose distribution and enable effective evaluation of cord dose sparing in spine SBRT. Methods: We present an active optical flow model (AOFM) to statistically describe cord dose variations and train a predictive model to represent correlations between AOFM and PTV contours. Thirty clinically accepted spine SBRT plans are evenly divided into training and testing datasets. The development of predictive model consists of 1) collecting a sequence of dose maps including PTV and OAR (spinal cord) as well as a set of associated PTV contours adjacent to OAR from the training dataset, 2) classifying data into five groups based on PTV's locations relative to OAR, two “Top”s, “Left”, “Right”, and “Bottom”, 3) randomly selecting a dose map as the reference in each group and applying rigid registration and optical flow deformation to match all other maps to the reference, 4) building AOFM by importing optical flow vectors and dose values into the principal component analysis (PCA), 5) applying another PCA to features of PTV and OAR contours to generate an active shape model (ASM), and 6) computing a linear regression model of correlations between AOFM and ASM.When predicting dose distribution of a new case in the testing dataset, the PTV is first assigned to a group based on its contour characteristics. Contour features are then transformed into ASM's principal coordinates of the selected group. Finally, voxel-level dose distribution is determined by mapping from the ASM space to the AOFM space using the predictive model. Results: The DVHs predicted by the AOFM-based model and those in clinical plans are comparable in training and testing datasets. At 2% volume the dose difference between predicted and clinical plans is 4.2±4.4% and 3.3±3.5% in the training and testing datasets, respectively. Conclusion: The AOFM is effective in predicting voxel-level dose distribution for spine SBRT. Partially supported by NIH

Organ dose conversion coefficients for voxel models of the reference male and female from idealized photon exposures

Science.gov (United States)

Schlattl, H.; Zankl, M.; Petoussi-Henss, N.

2007-04-01

A new series of organ equivalent dose conversion coefficients for whole body external photon exposure is presented for a standardized couple of human voxel models, called Rex and Regina. Irradiations from broad parallel beams in antero-posterior, postero-anterior, left- and right-side lateral directions as well as from a 360° rotational source have been performed numerically by the Monte Carlo transport code EGSnrc. Dose conversion coefficients from an isotropically distributed source were computed, too. The voxel models Rex and Regina originating from real patient CT data comply in body and organ dimensions with the currently valid reference values given by the International Commission on Radiological Protection (ICRP) for the average Caucasian man and woman, respectively. While the equivalent dose conversion coefficients of many organs are in quite good agreement with the reference values of ICRP Publication 74, for some organs and certain geometries the discrepancies amount to 30% or more. Differences between the sexes are of the same order with mostly higher dose conversion coefficients in the smaller female model. However, much smaller deviations from the ICRP values are observed for the resulting effective dose conversion coefficients. With the still valid definition for the effective dose (ICRP Publication 60), the greatest change appears in lateral exposures with a decrease in the new models of at most 9%. However, when the modified definition of the effective dose as suggested by an ICRP draft is applied, the largest deviation from the current reference values is obtained in postero-anterior geometry with a reduction of the effective dose conversion coefficient by at most 12%.

Organ dose conversion coefficients for voxel models of the reference male and female from idealized photon exposures

International Nuclear Information System (INIS)

Schlattl, H; Zankl, M; Petoussi-Henss, N

2007-01-01

A new series of organ equivalent dose conversion coefficients for whole body external photon exposure is presented for a standardized couple of human voxel models, called Rex and Regina. Irradiations from broad parallel beams in antero-posterior, postero-anterior, left- and right-side lateral directions as well as from a 360 deg. rotational source have been performed numerically by the Monte Carlo transport code EGSnrc. Dose conversion coefficients from an isotropically distributed source were computed, too. The voxel models Rex and Regina originating from real patient CT data comply in body and organ dimensions with the currently valid reference values given by the International Commission on Radiological Protection (ICRP) for the average Caucasian man and woman, respectively. While the equivalent dose conversion coefficients of many organs are in quite good agreement with the reference values of ICRP Publication 74, for some organs and certain geometries the discrepancies amount to 30% or more. Differences between the sexes are of the same order with mostly higher dose conversion coefficients in the smaller female model. However, much smaller deviations from the ICRP values are observed for the resulting effective dose conversion coefficients. With the still valid definition for the effective dose (ICRP Publication 60), the greatest change appears in lateral exposures with a decrease in the new models of at most 9%. However, when the modified definition of the effective dose as suggested by an ICRP draft is applied, the largest deviation from the current reference values is obtained in postero-anterior geometry with a reduction of the effective dose conversion coefficient by at most 12%

Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

Energy Technology Data Exchange (ETDEWEB)

Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States) and Department of Radiology, Duke University, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University, Durham, North Carolina 27705 (United States) and Departments of Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, Durham, North Carolina 27705 (United States)

2012-06-15

Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

Organ doses, effective doses, and risk indices in adult CT: Comparison of four types of reference phantoms across different examination protocols

International Nuclear Information System (INIS)

Zhang Yakun; Li Xiang; Paul Segars, W.; Samei, Ehsan

2012-01-01

Purpose: Radiation exposure from computed tomography (CT) to the public has increased the concern among radiation protection professionals. Being able to accurately assess the radiation dose patients receive during CT procedures is a crucial step in the management of CT dose. Currently, various computational anthropomorphic phantoms are used to assess radiation dose by different research groups. It is desirable to better understand how the dose results are affected by different choices of phantoms. In this study, the authors assessed the uncertainties in CT dose and risk estimation associated with different types of computational phantoms for a selected group of representative CT protocols. Methods: Routinely used CT examinations were categorized into ten body and three neurological examination categories. Organ doses, effective doses, risk indices, and conversion coefficients to effective dose and risk index (k and q factors, respectively) were estimated for these examinations for a clinical CT system (LightSpeed VCT, GE Healthcare). Four methods were used, each employing a different type of reference phantoms. The first and second methods employed a Monte Carlo program previously developed and validated in our laboratory. In the first method, the reference male and female extended cardiac-torso (XCAT) phantoms were used, which were initially created from the Visible Human data and later adjusted to match organ masses defined in ICRP publication 89. In the second method, the reference male and female phantoms described in ICRP publication 110 were used, which were initially developed from tomographic data of two patients and later modified to match ICRP 89 organ masses. The third method employed a commercial dosimetry spreadsheet (ImPACT group, London, England) with its own hermaphrodite stylized phantom. In the fourth method, another widely used dosimetry spreadsheet (CT-Expo, Medizinische Hochschule, Hannover, Germany) was employed together with its associated

CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT

International Nuclear Information System (INIS)

Christe, Andreas; Lin, Margaret C.; Yen, Andrew C.; Hallett, Rich L.; Roychoudhury, Kingshuk; Schmitzberger, Florian; Fleischmann, Dominik; Leung, Ann N.; Rubin, Geoffry D.; Vock, Peter; Roos, Justus E.

2012-01-01

Purpose: To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients. Materials and methods: Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35–83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study. Results: The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p = 0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal ‘mixed nodules’ decreased significantly at 20, 10 and 5 reference mAs (p < 0.05). At lower dose levels, classification drifted from ‘solid’ to ‘mixed nodule’, although no lesion was missed. Conclusion: Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections

Proposed Oral Reference Dose (RfD) for Barium and Compounds (Final Report, 2004)

Science.gov (United States)

This document is the final report from the 2004 external peer review of the Proposed Oral Reference Dose (RfD) for Barium and Compounds, prepared by the U.S. Environmental Protection Agency (EPA), National Center for Environmental Assessment (NCEA), for the Integrated Risk...

Radiation Dose to Newborns in Neonatal Intensive Care Units

International Nuclear Information System (INIS)

Bahreyni Toossi, M. T.; Malekzadeh, M.

2012-01-01

With the increase of X-ray use for medical diagnostic purposes, knowing the given doses is necessary in patients for comparison with reference levels. The concept of reference doses or diagnostic reference levels has been developed as a practical aid in the optimization of patient protection in diagnostic radiology. To assess the radiation doses to neonates from diagnostic radiography (chest and abdomen). This study has been carried out in the neonatal intensive care unit of a province in Iran. Entrance surface dose was measured directly with thermoluminescent dosimeters. The population included 195 neonates admitted for a diagnostic radiography, in eight NICUs of different hospital types. The mean entrance surface dose for chest and abdomen examinations were 76.3 μGy and 61.5 μGy, respectively. Diagnostic reference levels for neonate in NICUs of the province were 88 μGy for chest and 98 μGy for abdomen examinations that were slightly higher than other studies. Risk of death due to radiation cancer incidence of abdomens examination was equal to 1.88 × 10 -6 for male and 4.43 × 10 -6 for female. For chest X-ray, it was equal to 2.54 × 10 -6 for male and 1.17 × 10 -5 for female patients. Diagnostic reference levels for neonates in our province were slightly higher than values reported by other studies such as European national diagnostic reference levels and the NRPB reference dose. The main reason was related to using a high mAs and a low kVp applied in most departments and also a low focus film distance. Probably lack of collimation also affected some exams in the NICUs.

Dose coefficients for individual occupationally exposed

International Nuclear Information System (INIS)

2005-11-01

This Regulation refers to the requirements of the Regulation CNEN-NN.3.01, 'Basic Act of Radiological Protection', aiming its application to the dose calculation, with purposes of conformity verification with limits and restrictions of doses and level of reference for individual occupationally exposed, according to the express in its section 5

Adaptive Reference Levels in a Level-Crossing Analog-to-Digital Converter

Directory of Open Access Journals (Sweden)

Andrew C. Singer

2008-11-01

Full Text Available Level-crossing analog-to-digital converters (LC ADCs have been considered in the literature and have been shown to efficiently sample certain classes of signals. One important aspect of their implementation is the placement of reference levels in the converter. The levels need to be appropriately located within the input dynamic range, in order to obtain samples efficiently. In this paper, we study optimization of the performance of such an LC ADC by providing several sequential algorithms that adaptively update the ADC reference levels. The accompanying performance analysis and simulation results show that as the signal length grows, the performance of the sequential algorithms asymptotically approaches that of the best choice that could only have been chosen in hindsight within a family of possible schemes.

Patient grouping for dose surveys and establishment of diagnostic reference levels in paediatric computed tomography

International Nuclear Information System (INIS)

Vassileva, J.; Rehani, M.

2015-01-01

There has been confusion in literature on whether paediatric patients should be grouped according to age, weight or other parameters when dealing with dose surveys. The present work aims to suggest a pragmatic approach to achieve reasonable accuracy for performing patient dose surveys in countries with limited resources. The analysis is based on a subset of data collected within the IAEA survey of paediatric computed tomography (CT) doses, involving 82 CT facilities from 32 countries in Asia, Europe, Africa and Latin America. Data for 6115 patients were collected, in 34.5 % of which data for weight were available. The present study suggests that using four age groups, <1, >1-5, >5-10 and >10-15 y, is realistic and pragmatic for dose surveys in less resource countries and for the establishment of DRLs. To ensure relevant accuracy of results, data for >30 patients in a particular age group should be collected if patient weight is not known. If a smaller sample is used, patient weight should be recorded and the median weight in the sample should be within 5-10 % from the median weight of the sample for which the DRLs were established. Comparison of results from different surveys should always be performed with caution, taking into consideration the way of grouping of paediatric patients. Dose results can be corrected for differences in patient weight/age group. (authors)

Radiation doses from paediatric x-ray examinations in some hospitals in Khartoum Area

International Nuclear Information System (INIS)

Elshiekh, E.H.A.

2007-10-01

The aim of study was to evaluate the entrance surface doses (ESDs) and the effective dose (ED) to patients undergoing some common diagnostic x-ray examinations in large paediatric public hospitals in Khartoum State. ESD per examination was estimated from x-ray tube parameters in three hospitals comprising three units and sample of 449 radiographs. The entrance surface dose (ESD) and the effective dose (ED) were evaluated for chest, skull, abdomen, lumbar spine, and pelvis in antero-posterior (AP), postero-anterior (PA) and lateral (LAT) projections. For each examination, four age groups 0-1, 1-5, 5-10 and 10-15 years were studied. The DoseCal software was used to calculate these doses. In comparison between Sudanese hospitals with NRPB reference levels, all hospitals showed lower doses than reference levels except for the case of chest in A. Gasim and Khartoum hospitals. Wide variations for the chest examination have been detected. These variation were evident, in Sudan, from previous work. ESDs at Omdurman Hospital meet the reference levels for all years range. ESDs at Omdurman hospital were found to be 41μGy and 62 μGy for range 0-1 year, and 1-5 years, respectively, ESDs at A. Gasim Hospital was found found to be 65 μGy and 100 μGy for range 0-1 year, and 1-5 years, respectively. These values are above NRPB reference levels but lower than CEC1996 reference levels, and meet NRPB reference dose levels in range 5-10 years. In Khartoum Hospital the results present higher ESD than NRPB and CEC reference levels. The high ESDs reflect that ALARA principle is not being applied in chest examinations in Sudan. From comparison between results in this work with previous performed for chest cases in these Sudanese Hospitals at 2004, the ESDs in A. Gasim Hospital were above the previous result but meet the reference levels only range 5-10 years. Omdurman Hospital result but meet the reference levels for all years ranges and are lower than 2002 results. Khartoum Hospital

Guidance levels for diagnostic radiology in Romania

International Nuclear Information System (INIS)

Iacob, O.; Diaconescu, C.

2002-01-01

Over two decades surveys of radiological practice in Romania have demonstrated wide variations in patient dose levels between different hospitals. Local and national investigations revealed poor performances as well as of radiological equipment, darkroom procedure or technology of investigation. Hitherto, the annual collective effective dose to the population of Romania from diagnostic medical exposures attained a value of 13,820 manSv. Since the annual frequencies of radiological examinations remain unchanged over last ten years, this value is mostly attributed to the individual dose levels in different X-ray procedures. Notwithstanding the huge benefits to patients, the reduction of unnecessary exposures and individual doses are our principal concern and the establishment of national reference dose levels should solve this problem. British experience demonstrated that reference doses are a practical tool in this purpose and the adoption of national reference dose values indicated an overall improvement in patient exposure. Even the local of reference dose values proved a useful way to achieve patient dose reduction. In meantime the optimization of patient protection, each X-ray examination should be conducted with lowest necessary dose to achieve the clinical aim. This paper presents the first approach to establish local reference dose levels for some diagnostic examinations based on the measurements made in six (from the eighth of Eastern territory of Romania) districts, invited to cooperate in this end

Estimating Radiological Doses to Predators Foraging in a Low-Level Radioactive Waste Management Area

International Nuclear Information System (INIS)

L.Soholt; G.Gonzales; P.Fresquez; K.Bennett; E.Lopez

2003-01-01

Since 1957, Los Alamos National Laboratory has operated Area G as its low-level, solid radioactive waste management and disposal area. Although the waste management area is developed, plants, small mammals, and avian and mammalian predators still occupy the less disturbed and revegetated portions of the land. For almost a decade, we have monitored the concentrations of selected radionuclides in soils, plants, and small mammals at Area G. The radionuclides tritium, plutonium-238, and plutonium-239 are regularly found at levels above regional background in all three media. Based on radionuclide concentrations in mice collected from 1994 to 1999, we calculated doses to higher trophic levels (owl, hawk, kestrel, and coyote) that forage on the waste management area. These predators play important functions in the regional ecosystems and are an important part of local Native American traditional tales that identify the uniqueness of their culture. The estimated doses are compared to Department of Energy's interim limit of 0.1 rad/day for the protection of terrestrial wildlife. We used exposure parameters that were derived from the literature for each receptor, including Environmental Protection Agency's exposure factors handbook. Estimated doses to predators ranged from 9E-06 to 2E-04 rad/day, assuming that they forage entirely on the waste management area. These doses are greater than those calculated for predators foraging exclusively in reference areas, but are still well below the interim dose limit. We believe that these calculated doses represent upper-bound estimates of exposure for local predators because the larger predators forage over areas that are much greater than the 63-acre waste management area. Based on these results, we concluded that predators foraging on this area do not face a hazard from radiological exposure under current site conditions

Calculation of local skin doses with ICRP adult mesh-type reference computational phantoms

Science.gov (United States)

Yeom, Yeon Soo; Han, Haegin; Choi, Chansoo; Nguyen, Thang Tat; Lee, Hanjin; Shin, Bangho; Kim, Chan Hyeong; Han, Min Cheol

2018-01-01

Recently, Task Group 103 of the International Commission on Radiological Protection (ICRP) developed new mesh-type reference computational phantoms (MRCPs) for adult males and females in order to address the limitations of the current voxel-type reference phantoms described in ICRP Publication 110 due to their limited voxel resolutions and the nature of the voxel geometry. One of the substantial advantages of the MRCPs over the ICRP-110 reference phantoms is the inclusion of a 50-μm-thick radiosensitive skin basal-cell layer; however, a methodology for calculating the local skin dose (LSD), i.e., the maximum dose to the basal layer averaged over a 1-cm2 area, has yet to be developed. In the present study, a dedicated program for the LSD calculation with the MRCPs was developed based on the mean shift algorithm and the Geant4 Monte Carlo code. The developed program was used to calculate local skin dose coefficients (LSDCs) for electrons and alpha particles, which were then compared with the values given in ICRP Publication 116 that were produced with a simple tissue-equivalent cube model. The results of the present study show that the LSDCs of the MRCPs are generally in good agreement with the ICRP-116 values for alpha particles, but for electrons, significant differences are found at energies higher than 0.15 MeV. The LSDCs of the MRCPs are greater than the ICRP-116 values by as much as 2.7 times at 10 MeV, which is due mainly to the different curvature between realistic MRCPs ( i.e., curved) and the simple cube model ( i.e., flat).

Radiation dose from solar flares at ground level

International Nuclear Information System (INIS)

O'Brien, K.

1979-01-01

Wdowczyk and Wolfendale (Nature, 268, 510, 1977) concluded that a very large solar flare producing exposure of 10 4 rad at ground level (lethal to almost any organism) has a possible frequency of once per 10 5 -10 8 yr. In the work reported similar results were obtained using a more elaborate model. Flares occuring from February 1956 to August 1972 were analyzed. The flare size distribution above the earth's atmosphere, and neutron flux, dose and dose equivalent at ground level at the latitude of Deep River, Canada, were calculated. The probable frequency of flares delivering various doses are given. Doses larger than 100 rad which have significant somatic effects on man and other animals may be delivered once in 10 6 years. The probability of 10 4 rad was found to be 10 -8 /yr. These calculations apply only to high geomagnetic latitudes. Field reversals during which the geomagnetic field is much weaker than current values total about 10% of the past 4 million years. This suggests that a very large flare delivering a large dose worldwide at ground level cannot be ruled out. (author)

Patient Dose During Carotid Artery Stenting With Embolic-Protection Devices: Evaluation With Radiochromic Films and Related Diagnostic Reference Levels According to Factors Influencing the Procedure

Energy Technology Data Exchange (ETDEWEB)

D' Ercole, Loredana, E-mail: l.dercole@smatteo.pv.it [Fondazione IRCCS Policlinico San Matteo, Department of Medical Physics (Italy); Quaretti, Pietro; Cionfoli, Nicola [Fondazione IRCCS Policlinico San Matteo, Department of Radiology (Italy); Klersy, Catherine [Fondazione IRCCS Policlinico San Matteo, Biometry and Clinical Epidemiology Service, Research Department, (Italy); Bocchiola, Milena [Fondazione IRCCS Policlinico San Matteo, Department of Medical Physics (Italy); Rodolico, Giuseppe; Azzaretti, Andrea [Fondazione IRCCS Policlinico San Matteo, Department of Radiology (Italy); Lisciandro, Francesco [Fondazione IRCCS Policlinico San Matteo, Department of Medical Physics (Italy); Cascella, Tommaso; Zappoli Thyrion, Federico [Fondazione IRCCS Policlinico San Matteo, Department of Radiology (Italy)

2013-04-15

To measure the maximum entrance skin dose (MESD) on patients undergoing carotid artery stenting (CAS) using embolic-protection devices, to analyze the dependence of dose and exposure parameters on anatomical, clinical, and technical factors affecting the procedure complexity, to obtain some local diagnostic reference levels (DRLs), and to evaluate whether overcoming DRLs is related to procedure complexity. MESD were evaluated with radiochromic films in 31 patients (mean age 72 {+-} 7 years). Five of 33 (15 %) procedures used proximal EPD, and 28 of 33 (85 %) procedures used distal EPD. Local DRLs were derived from the recorded exposure parameters in 93 patients (65 men and 28 women, mean age 73 {+-} 9 years) undergoing 96 CAS with proximal (33 %) or distal (67 %) EPD. Four bilateral lesions were included. MESD values (mean 0.96 {+-} 0.42 Gy) were <2 Gy without relevant dependence on procedure complexity. Local DRL values for kerma area product (KAP), fluoroscopy time (FT), and number of frames (N{sub FR}) were 269 Gy cm{sup 2}, 28 minutes, and 251, respectively. Only simultaneous bilateral treatment was associated with KAP (odds ratio [OR] 10.14, 95 % confidence interval [CI] 1-102.7, p < 0.05) and N{sub FR} overexposures (OR 10.8, 95 % CI 1.1-109.5, p < 0.05). Type I aortic arch decreased the risk of FT overexposure (OR 0.4, 95 % CI 0.1-0.9, p = 0.042), and stenosis {>=} 90 % increased the risk of N{sub FR} overexposure (OR 2.8, 95 % CI 1.1-7.4, p = 0.040). At multivariable analysis, stenosis {>=} 90 % (OR 2.8, 95 % CI 1.1-7.4, p = 0.040) and bilateral treatment (OR 10.8, 95 % CI 1.1-109.5, p = 0.027) were associated with overexposure for two or more parameters. Skin doses are not problematic in CAS with EPD because these procedures rarely lead to doses >2 Gy.

Optimisation of radioprotection of patients in nuclear medicine: assessment of doses for the new ICRP's reference voxelized phantoms

International Nuclear Information System (INIS)

Hadid, L.; Blanchardon, E.; Desbree, A.; Makovicka, L.; Zankl, M.

2010-01-01

As the ICPR (International Commission on Radiological Protection) decided to adopt voxelized phantoms to emulate a reference adult, the authors report the validation of calculations of the SFAs (specific absorbed fractions) for the new ICPR's reference phantoms. After a presentation of these phantoms, the authors briefly present the OEDIPE software which is used to compute the SAFs and notably the absorbed doses. They discuss the results obtained for the SAFs (for photons and for electrons) and for the doses

An N+3 Technology Level Reference Propulsion System

Science.gov (United States)

Jones, Scott M.; Haller, William J.; Tong, Michael To-Hing

2017-01-01

An N+3 technology level engine, suitable as a propulsion system for an advanced single-aisle transport, was developed as a reference cycle for use in technology assessment and decision-making efforts. This reference engine serves three main purposes: it provides thermodynamic quantities at each major engine station, it provides overall propulsion system performance data for vehicle designers to use in their analyses, and it can be used for comparison against other proposed N+3 technology-level propulsion systems on an equal basis. This reference cycle is meant to represent the expected capability of gas turbine engines in the N+3 timeframe given reasonable extrapolations of technology improvements and the ability to take full advantage of those improvements.

Carcinogenesis and low-level ionizing radiation with special reference to lung cancer and exposure to radon daughters

Energy Technology Data Exchange (ETDEWEB)

Fabrikant, J.I.

1982-04-01

Of the important health effects of ionizing radiation, three important late effects - carcinogenesis, teratogenesis and mutagenesis are of greatest concern. This is because any exposure, even at low levels, carries some risk of such deleterious effects. As the dose of radiation increases above very low levels, the risk of health effects increases. Cancer-induction is the most important late somatic effect of low-dose ionizing radiation. Solid cancers, rather than leukemia, are principal late effects in exposed individuals. Tissues vary greatly in their susceptibility to radiation carcinogenesis. The most frequently occurring radiation-induced cancers in man include, in decreasing order of susceptibility: the female breast, the thyroid gland, the blood-forming tissues, the lung, certain organs of the gastrointestinal tract, and the bones. A number of biological and physical factors affect the cancer risk, such as age, sex, life-style, LET, and RBE. Despite uncertainty about low-level radiation risks, regulatory and advisory bodies must set standards for exposure, and individuals need information to be able to make informed judgments for themselves. From the point of view of the policy maker, the overriding concern is the fact that small doses of radiation can cause people to have more cancers than would otherwise be expected. While concern for all radiation effects exists, our human experience is limited to cancer-induction in exposed populations. This discussion is limited to cancer risk estimation and decision-making in relation to the health effects on populations of exposure to low levels of ionizing radiation. Here, low-level radiation will refer to yearly whole-body doses up to 5 rems or 0.05 Sv, or to cumulative doses up to 50 rems or 0.5 Sv from low-LET radiation and from high-LET radiation. (ERB)

Carcinogenesis and low-level ionizing radiation with special reference to lung cancer and exposure to radon daughters

International Nuclear Information System (INIS)

Fabrikant, J.I.

1982-04-01

Of the important health effects of ionizing radiation, three important late effects - carcinogenesis, teratogenesis and mutagenesis are of greatest concern. This is because any exposure, even at low levels, carries some risk of such deleterious effects. As the dose of radiation increases above very low levels, the risk of health effects increases. Cancer-induction is the most important late somatic effect of low-dose ionizing radiation. Solid cancers, rather than leukemia, are principal late effects in exposed individuals. Tissues vary greatly in their susceptibility to radiation carcinogenesis. The most frequently occurring radiation-induced cancers in man include, in decreasing order of susceptibility: the female breast, the thyroid gland, the blood-forming tissues, the lung, certain organs of the gastrointestinal tract, and the bones. A number of biological and physical factors affect the cancer risk, such as age, sex, life-style, LET, and RBE. Despite uncertainty about low-level radiation risks, regulatory and advisory bodies must set standards for exposure, and individuals need information to be able to make informed judgments for themselves. From the point of view of the policy maker, the overriding concern is the fact that small doses of radiation can cause people to have more cancers than would otherwise be expected. While concern for all radiation effects exists, our human experience is limited to cancer-induction in exposed populations. This discussion is limited to cancer risk estimation and decision-making in relation to the health effects on populations of exposure to low levels of ionizing radiation. Here, low-level radiation will refer to yearly whole-body doses up to 5 rems or 0.05 Sv, or to cumulative doses up to 50 rems or 0.5 Sv from low-LET radiation and from high-LET radiation

Organ doses for reference pediatric and adolescent patients undergoing computed tomography estimated by Monte Carlo simulation

International Nuclear Information System (INIS)

Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel J.; Bolch, Wesley E.

2012-01-01

Purpose: To establish an organ dose database for pediatric and adolescent reference individuals undergoing computed tomography (CT) examinations by using Monte Carlo simulation. The data will permit rapid estimates of organ and effective doses for patients of different age, gender, examination type, and CT scanner model. Methods: The Monte Carlo simulation model of a Siemens Sensation 16 CT scanner previously published was employed as a base CT scanner model. A set of absorbed doses for 33 organs/tissues normalized to the product of 100 mAs and CTDI vol (mGy/100 mAs mGy) was established by coupling the CT scanner model with age-dependent reference pediatric hybrid phantoms. A series of single axial scans from the top of head to the feet of the phantoms was performed at a slice thickness of 10 mm, and at tube potentials of 80, 100, and 120 kVp. Using the established CTDI vol - and 100 mAs-normalized dose matrix, organ doses for different pediatric phantoms undergoing head, chest, abdomen-pelvis, and chest-abdomen-pelvis (CAP) scans with the Siemens Sensation 16 scanner were estimated and analyzed. The results were then compared with the values obtained from three independent published methods: CT-Expo software, organ dose for abdominal CT scan derived empirically from patient abdominal circumference, and effective dose per dose-length product (DLP). Results: Organ and effective doses were calculated and normalized to 100 mAs and CTDI vol for different CT examinations. At the same technical setting, dose to the organs, which were entirely included in the CT beam coverage, were higher by from 40 to 80% for newborn phantoms compared to those of 15-year phantoms. An increase of tube potential from 80 to 120 kVp resulted in 2.5-2.9-fold greater brain dose for head scans. The results from this study were compared with three different published studies and/or techniques. First, organ doses were compared to those given by CT-Expo which revealed dose differences up to

Evaluation of alanine as a reference dosimeter for therapy level dose comparisons in megavoltage electron beams

International Nuclear Information System (INIS)

McEwen, Malcolm; Sharpe, Peter; Voros, Sandor

2015-01-01

When comparing absorbed dose standards from different laboratories (e.g. National Measurement Institutes, NMIs, for Key or Supplementary comparisons) it is rarely possible to carry out a direct comparison of primary standard instruments, and therefore some form of transfer detector is required. Historically, air-filled, unsealed ionization chambers have been used because of the long history of using these instruments, very good stability over many years, and ease of transport. However, the use of ion chambers for therapy-level comparisons is not without its problems. Findings from recent investigations suggest that ion chambers are prone to non-random variations, they are not completely robust to standard courier practices, and failure at any step in a comparison can render all measurements potentially useless. An alternative approach is to identify a transfer system that is insensitive to some of these concerns - effectively a dosimeter that is inexpensive, simple to use, robust, but with sufficient precision and of a size relevant to the disseminated quantity in question. The alanine dosimetry system has been successfully used in a number of situations as an audit dosimeter and therefore the purpose of this investigation was to determine whether alanine could also be used as the transfer detector for dosimetric comparisons, which require a lower value for the measurement uncertainty. A measurement protocol was developed for comparing primary standards of absorbed dose to water in high-energy electron beams using alanine pellets irradiated in a water-equivalent plastic phantom. A trial comparison has been carried out between three NMIs and has indicated that alanine is a suitable alternative to ion chambers, with the system used achieving a precision of 0.1%. Although the focus of the evaluation was on the performance of the dosimeter, the comparison results are encouraging, showing agreement at the level of the combined uncertainties (∼0.6%). Based on this

Comparison of internal dose estimates obtained using organ-level, voxel S value, and Monte Carlo techniques

Energy Technology Data Exchange (ETDEWEB)

Grimes, Joshua, E-mail: grimes.joshua@mayo.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver V5Z 1L8 (Canada); Celler, Anna [Department of Radiology, University of British Columbia, Vancouver V5Z 1L8 (Canada)

2014-09-15

Purpose: The authors’ objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-specific anatomy on the final dose estimate. Methods: Six patients injected with{sup 99m}Tc-hydrazinonicotinamide-Tyr{sup 3}-octreotide were included in this study. A hybrid planar/SPECT imaging protocol was used to estimate {sup 99m}Tc time-integrated activity coefficients (TIACs) for kidneys, liver, spleen, and tumors. Additionally, TIACs were predicted for {sup 131}I, {sup 177}Lu, and {sup 90}Y assuming the same biological half-lives as the {sup 99m}Tc labeled tracer. The TIACs were used as input for OLINDA/EXM for organ-level dose calculation and voxel level dosimetry was performed using the voxel S value method and Monte Carlo simulation. Dose estimates for {sup 99m}Tc, {sup 131}I, {sup 177}Lu, and {sup 90}Y distributions were evaluated by comparing (i) organ-level S values corresponding to each method, (ii) total tumor and organ doses, (iii) differences in right and left kidney doses, and (iv) voxelized dose distributions calculated by Monte Carlo and the voxel S value technique. Results: The S values for all investigated radionuclides used by OLINDA/EXM and the corresponding patient-specific S values calculated by Monte Carlo agreed within 2.3% on average for self-irradiation, and differed by as much as 105% for cross-organ irradiation. Total organ doses calculated by OLINDA/EXM and the voxel S value technique agreed with Monte Carlo results within approximately ±7%. Differences between right and left kidney doses determined by Monte Carlo were as high as 73%. Comparison of the Monte Carlo and voxel S value dose distributions showed that each method produced similar dose volume histograms with a minimum dose covering 90% of the volume (D90

Internal and external dose conversion coefficient for domestic reference animals and plant

Energy Technology Data Exchange (ETDEWEB)

Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Park, Du Won; Choi, Young Ho

2009-07-15

This report presents the internal and external dose conversion coefficients for domestic reference animals and plant, which are essential to assess the radiological impact of an environmental radiation on non-human species. To calculate the dose conversion coefficients, a uniform isotropic model and a Monte Carlo method for a photon transport simulation in environmental media with different densities have been applied for aquatic and terrestrial animals, respectively. In the modeling all the target animals are defined as a simple 3D elliptical shape. To specify the external radiation source it is assumed that aquatic animals are fully immersed in infinite and uniformly contaminated water, and the on-soil animals are living on the surface of a horizontally infinite soil source, and the in-soil organisms are living at the center of a horizontally infinite and uniformly contaminated soil to a depth of 50cm. A set of internal and external dose conversion coefficients for 8 Korean reference animals and plant (rat, roe-deer, frog, snake, Chinese minnow, bee, earthworm, and pine tree) are presented for 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, {sup 95}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, and {sup 240}Pu)

Order of 24 October 2011 related to diagnosis reference levels in radiology and nuclear medicine; Arrete du 24 octobre 2011 relatif aux niveaux de reference diagnostiques en radiologie et en medecine nucleaire

Energy Technology Data Exchange (ETDEWEB)

Grall, J.Y. [Ministere du travail, de l' emploi et de la sante, Direction generale de la sante, 14, avenue Duquesne, 75350 PARIS 07 SP (France)

2012-01-14

This order defines diagnosis reference levels for examinations exposing to the most common or irradiating ionizing radiations in the case of radiology and nuclear medicine. It also specifies the role of the person authorized to use nuclear medicine equipment, the role of the IRSN in collecting and analysing data. Doses are specified in appendix for different types of examinations

Evaluation of multiple scan average dose (MSAD) levels in computerized tomography in Minas Gerais state, Brazil

International Nuclear Information System (INIS)

Alonso, Thessa C.; Vieira, Leandro de A.; Barbosa, Nayra V.; Oliveira, Jeyselaine R. de; Cesar, Adriana C.Z.; Silva, Teogenes A. da

2014-01-01

Computed Tomography (CT) grows every year and is a diagnostic method that has revolutionized radiology with advances in procedures for obtaining image. However, the indiscriminate use of this method generates relatively high doses in patients. The diagnostic reference levels (DRLs) is a practical tool to promote the evaluation of existing protocols. The optimization and the periodic review of the protocols are important to balance the risk of radiation. The present study aims to conduct a survey of levels of MSAD of Minas Gerais following the procedures recommended by current Brazilian law. (author)

Towards the definition of Institutional diagnostic reference levels in paediatric interventional cardiology procedures in Greece.

Science.gov (United States)

Kottou, S; Kollaros, N; Plemmenos, C; Mastorakou, I; Apostolopoulou, S C; Tsapaki, V

2018-02-01

This study aimed to evaluate paediatric radiation doses in a dedicated cardiology hospital, with the objective of characterising patterns in dose variation. The ultimate purpose was to define Local (Institutional) Diagnostic Reference Levels (LDRLs) for different types of paediatric cardiac interventional procedures (IC), according to patient age. From a total of 710 cases performed during three consecutive years, by operators with more than 15 years of experience, the age was noted in only 477 IC procedures. The median values obtained for Fluoroscopy Time (FT), Number of Frames (N) and Kerma Area Product (P KA ) by age range were 5.8 min, 1322 and 2.0 Gy.cm 2 for definition of LDRLs presents challenges mainly due to the multiple clinical and technical factors affecting the outcome. On the other hand the lack of paediatric IC DRLs makes the identification of good practices more difficult. A consensus is needed on IC procedures nomenclature and grouping in order to allow a common assessment and comparison of doses. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

CERN Document Server

Endo, A; Zankl, M; Bolch, W E; Eckerman, K F; Hertel, N E; Hunt, J G; Pelliccioni, M; Schlattl, H; Menzel, H-G

2014-01-01

This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors.

SU-E-I-33: Establishment of CT Diagnostic Reference Levels in Province Nova Scotia

Energy Technology Data Exchange (ETDEWEB)

Tonkopi, E; Abdolell, M; Duffy, S [Dalhousie University and Queen Elizabeth II Health Sciences Centre, Halifax, NS (Canada)

2015-06-15

Purpose: To evaluate patient radiation dose from the most frequently performed CT examinations and to establish provincial diagnostic reference levels (DRLs) as a tool for protocol optimization. Methods: The study investigated the following CT examinations: head, chest, abdomen/pelvis, and chest/abdomen/pelvis (CAP). Dose data, volume CT dose index (CTDIvol) and dose-length product (DLP), were collected from 15 CT scanners installed during 2004–2014 in 11 hospital sites of Nova Scotia. All scanners had dose modulation options and multislice capability (16–128 detector rows). The sample for each protocol included 15 average size patients (70±20 kg). Provincial DRLs were calculated as the 75th percentile of patient dose distributions. The differences in dose between hospitals were evaluated with a single factor ANOVA statistical test. Generalized linear modeling was used to determine the factors associated with higher radiation dose. A sample of 36 abdominal studies performed on three different scanners was blinded and randomized for an assessment by an experienced radiologist who graded the imaging quality of anatomic structures. Results: Data for 900 patients were collected. The DRLs were proposed using CTDIvol (mGy) and DLP (mGy*cm) values for CT head (67 and 1049, respectively), chest (12 and 393), abdomen/pelvis (16 and 717), and CAP (14 and 1034). These DRLs were lower than the published national data except for the head CTDIvol. The differences between the means of the dose distributions from each scanner were statistically significant (p<0.05) for all examinations. A very weak correlation was found between the dose and the scanner age or the number of slices with Pearson’s correlation coefficients of 0.011–0.315. The blinded analysis of image quality demonstrated no clinically significant difference except for the noise category. Conclusion: Provincial DRLs were established for typical CT examinations. The variations in dose between the hospitals

The Basic Principles in Assessment and Selection of Reference Doses: Considerations in Nuclear Medicine (invited paper)

International Nuclear Information System (INIS)

Mattsson, S.; Jacobsson, L.; Vestergren, E.

1998-01-01

The possible ways to optimise the relation between diagnostic information and patient absorbed dose differ between nuclear medicine and X ray imaging. In nuclear medicine, very little has been done to find an optimal dosage of radiopharmaceuticals. Current nuclear medicine methods are discussed in the light of the recent ICRP Publications and the new EU Patient Directive. The paper also discusses how reference levels for administered activity may be derived from patient studies. In order to eliminate the most inappropriate choices (too low or too high activities), knowledge of the current statistical distribution of administered activities may be helpful. Different methods to estimate the amount of activity that should be administered to children of various body sizes to guarantee the same image quality as for adults are also discussed. Examples of current activity levels for common nuclear medicine procedures, indicating the state of the practice, are given. (author)

Investigation of reference levels and radiation dose associated with abdominal EVAR (endovascular aneurysm repair) procedures across several European Centres

Energy Technology Data Exchange (ETDEWEB)

Tuthill, E.; Rainford, L. [University College Dublin, Diagnostic Imaging, School of Medicine, Dublin (Ireland); O' Hora, L.; O' Donohoe, M. [Mater Misericordiae University Hospital, Dublin (Ireland); Panci, S. [San Giovanni di Dio Hospital, Florence (Italy); Gilligan, P.; Fox, E. [Mater Private Hospital, Dublin (Ireland); Campion, D. [Mauriziano-Umberto Hospital, Turin (Italy); Trenti, R. [Policlinico S. Orsola-Malpighi, Bologna (Italy); Catania, D. [AITRI, Association of Italian Interventional Radiographers, Milan (Italy)

2017-11-15

Endovascular aneurysm repair (EVAR) is considered the treatment of choice for abdominal aortic aneurysms with suitable anatomy. In order to improve radiation safety, European Directive (2013/59) requires member states to implement diagnostic reference levels (DRLs) in radio-diagnostic and interventional procedures. This study aimed to determine local DRLs for EVAR across five European centres and identify an interim European DRL, which currently remains unestablished. Retrospective data was collected for 180 standard EVARs performed between January 2014 and July 2015 from five specialist centres in Ireland (n=2) and Italy (n=3). Data capture included: air kerma-area product (P{sub KA}), total air kerma at the reference point (K{sub a,r}), fluoroscopic time (FT), number of acquisitions, frame rate of acquisition, type of acquisition, patient height, weight, and gender. The mean values for each site A, B, C, D, and E were: P{sub KA}s of 4343 ± 994 μGym{sup 2}, 18,200 ± 2141 μGym{sup 2}, 11,423 ± 1390 μGym{sup 2}, 7796 ± 704 μGym{sup 2}, 31,897 ± 5798 μGym{sup 2}; FTs of 816 ± 92 s, 950 ± 150 s, 708 ± 70 s, 972 ± 61 s, 827 ± 118 s; and number of acquisitions of 6.72 ± 0.56, 10.38 ± 1.54, 4.74 ± 0.19, 5.64 ± 0.36, 7.28 ± 0.65, respectively. The overall pooled 75th percentile P{sub KA} was 15,849 μGym{sup 2}. Local reference levels were identified. The pooled data has been used to establish an interim European DRL for EVAR procedures. (orig.)

Environmental policy. Ambient radioactivity levels and radiation doses in 1998

International Nuclear Information System (INIS)

1999-11-01

The report contains information on the natural (background) radiation exposure (chapter II), the natural radiation exposure as influenced by anthropogenic effects (chapter III), the anthropogenic radiation exposure (chapter IV), and the radiation doses to the environment and the population emanating from the Chernobyl fallout (chapter V). The natural radiation exposure is specified referring to the contributions from cosmic and terrestrial background radiation and intake of natural radioactive substances. Changes of the natural environment resulting from anthropogenic effects (technology applications) inducing an increase in concentration of natural radioactive substances accordingly increase the anthropogenic radiation exposure. Indoor air radon concentration in buildings for instance is one typical example of anthropogenic increase of concentration of natural radioactivity, primarily caused by the mining industry or by various materials processing activities, which may cause an increase in the average radiation dose to the population. Measurements so far show that indoor air concentration of radon exceeds a level of 200 Bq/m 3 in less than 2% of the residential buildings; the EUropean Commission therefore recommends to use this concentration value as a maximum value for new residential buildings. Higher concentrations are primarily measured in areas with relevant geological conditions and abundance of radon, or eg. in mining areas. (orig./CB) [de

Pulmonary disease in cystic fibrosis: assessment with chest CT at chest radiography dose levels.

Science.gov (United States)

Ernst, Caroline W; Basten, Ines A; Ilsen, Bart; Buls, Nico; Van Gompel, Gert; De Wachter, Elke; Nieboer, Koenraad H; Verhelle, Filip; Malfroot, Anne; Coomans, Danny; De Maeseneer, Michel; de Mey, Johan

2014-11-01

To investigate a computed tomographic (CT) protocol with iterative reconstruction at conventional radiography dose levels for the assessment of structural lung abnormalities in patients with cystic fibrosis ( CF cystic fibrosis ). In this institutional review board-approved study, 38 patients with CF cystic fibrosis (age range, 6-58 years; 21 patients 18 years) underwent investigative CT (at minimal exposure settings combined with iterative reconstruction) as a replacement of yearly follow-up posteroanterior chest radiography. Verbal informed consent was obtained from all patients or their parents. CT images were randomized and rated independently by two radiologists with use of the Bhalla scoring system. In addition, mosaic perfusion was evaluated. As reference, the previous available conventional chest CT scan was used. Differences in Bhalla scores were assessed with the χ(2) test and intraclass correlation coefficients ( ICC intraclass correlation coefficient s). Radiation doses for CT and radiography were assessed for adults (>18 years) and children (chest CT protocol can replace the two yearly follow-up chest radiographic examinations without major dose penalty and with similar diagnostic quality compared with conventional CT.

Determination of carbon-14 in environmental level, solid reference materials

Energy Technology Data Exchange (ETDEWEB)

Blowers, Paul, E-mail: paul.blowers@cefas.co.uk [Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk, NR33 0HT (United Kingdom); Caborn, Jane, E-mail: jane.a.caborn@nnl.co.uk [NNL, Springfields, Salwick, Preston, Lancashire, PR4 0XJ (United Kingdom); Dell, Tony [Veterinary Laboratories Agency, New Haw, Addlestone, Surrey, KT15 3NB (United Kingdom); Gingell, Terry [DSTL, Radiation Protection Services, Crescent Road, Alverstoke, Gosport, Hants, PO12 2DL (United Kingdom); Harms, Arvic [National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom); Long, Stephanie [Radiological Protection Institute of Ireland, 3 Clonskeagh Square, Clonskeagh Road, Dublin 14, Ireland (United Kingdom); Sleep, Darren [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP (United Kingdom); Stewart, Charlie [UKAEA (Waste Management Group), Chemical Support Services, D1310/14, Dounreay, Thurso, Caithness, KW14 7TZ (United Kingdom); Walker, Jill [Radiocarbon Dating, The Old Stables, East Lockinge, Wantage, Oxon OX12 8QY (United Kingdom); Warwick, Phil E. [GAU-Radioanalytical, National Oceanography Centre Southampton, European Way, Southampton, SO14 3ZH (United Kingdom)

2011-10-15

An intercomparison exercise to determine the {sup 14}C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing {sup 14}C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

Determination of carbon-14 in environmental level, solid reference materials

International Nuclear Information System (INIS)

Blowers, Paul; Caborn, Jane; Dell, Tony; Gingell, Terry; Harms, Arvic; Long, Stephanie; Sleep, Darren; Stewart, Charlie; Walker, Jill; Warwick, Phil E.

2011-01-01

An intercomparison exercise to determine the 14 C activity concentrations in a range of solid, environmental level materials was conducted between laboratories in the UK. IAEA reference materials, C2, C6 and C7, and an in-house laboratory QA material were dispatched in 2006 to ten laboratories comprising of members of the Analyst Informal Working Group (AIWG) and one other invited party. The laboratories performed the determinations using a number of techniques, and using the results each one was evaluated in terms of levels of precision, sensitivity and limits of detection. The results of the study show that all techniques are capable of successfully analysing 14 C in environmental level materials, however, a shortage of certified environmental reference materials exists. The suitability of the IAEA reference materials and other material for use as reference materials was also assessed.

Practical experience of monitoring patient dose

Energy Technology Data Exchange (ETDEWEB)

McDonnell, C.; Shrimpton, P. (National Radiological Protection Board, Chilton (United Kingdom)); O' Mahoney, M. (National Radiological Protection Board, Leeds (United Kingdom)); Foster, J. (Nuffield Hospitals, Surbiton (United Kingdom))

1994-05-01

NRPB recommends the use of reference dose levels for diagnostic medical exposures as an aid to patient dose reduction, but is this approach effective This article describes the broadly encouraging experiences of one large group of hospitals in carrying out measurements of entrance surface dose on patients undergoing some common types of x-ray examination. (author).

Sci-Thur PM – Colourful Interactions: Highlights 07: Canadian Computed Tomography Survey: National Diagnostic Reference Levels

Energy Technology Data Exchange (ETDEWEB)

Wardlaw, Graeme M; Martel, Narine [Consumer & Clinical Radiation Protection Bureau / Health Canada (Canada)

2016-08-15

Purpose: The Canadian Computed (CT) Tomography Survey sought to collect CT technology and dose index data (CTDI and DLP) at the national level in order to establish national diagnostic reference levels (DRLs) for seven common CT examinations of standard-sized adults and pediatric patients. Methods: A single survey booklet (consisting of four sections) was mailed to and completed for each participating CT scanner. Survey sections collected data on (i) General facility and scanner information, (ii) routine protocols (as available), (iii) individual patient data (as applied) and (iv) manual CTDI measurements. Results: Dose index (CTDIvol and DLP) and associated patient data from 24 280 individual patient exam sequences was analyzed for seven common CT examinations performed in Canada: Adult Head, Chest, Abdomen/Pelvis, and Chest/Abdomen/Pelvis, and Pediatric Head, Chest, and Abdomen. Pediatric examination data was sub-divided into three age ranges: 0–3, 3–7 and 7–13 years. DRLs (75th percentile of dose index distributions) were found for all thirteen groups. Further analysis also permitted segmentation of examination data into 8 sub-groups, whose dose index data was displayed along with group histograms – showing relative contribution of axial vs. helical, contrast use (C+ vs. C-), and application of fixed current vs. dose reduction (DR) – 75th percentiles of DR sub-groups were, in almost all cases, lower than whole group (examination) DRLs. Conclusions: The analysis and summaries presented in the pending survey report can serve to aid local CT imaging optimization efforts within Canada and also contribute further to international efforts in radiation protection of patients.

Diagnostic radiography dose and guidance levels

International Nuclear Information System (INIS)

Cuadros, M.; Augusto, A.

2001-01-01

This work shows a study done on conventional radiodiagnostic equipment. The evaluation was implemented throughout different areas of Bolivia, covering not only single equipment radiographs used in the cities, but also the ones used in rural areas. There have been more than 90 equipment pieces evaluated of which the dose received by a patient for a given exam has been considered an essential element. For this purpose two types of examinations have been selected, these being considered the more frequent. Not only the dose aspect was taken into consideration but the technique used as well. These elements that support very important information have been related to orientative levels. (author)

Reference hearing threshold levels for short duration signals

DEFF Research Database (Denmark)

Poulsen, Torben; Legarth, Søren Vase

2008-01-01

for the determination of reference hearing threshold levels. The results are given as peak-to-peak equivalent threshold sound pressure levels (peETSPL). The results are in good agreement with other sparse results from literature and are part of the basis for the ISO 389-6 standard from 2007....

Impact on Dose Coefficients Calculated with ICRP Adult Mesh-type Reference Computational Phantoms

Energy Technology Data Exchange (ETDEWEB)

Yeom, Yeon Soo; Nguyen, Thang Tat; Choi, Chan Soo; Lee, Han Jin; Han, Hae Gin; Han, Min Cheol; Shin, Bang Ho; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

2017-04-15

In 2016, the International Commission on Radiological Protection (ICRP) formulated a new Task Group (TG) (i.e., TG 103) within Committee 2. The ultimate aim of the TG 103 is to develop the mesh-type reference computational phantoms (MRCPs) that can address dosimetric limitations of the currently used voxel-type reference computational phantoms (VRCPs) due to their limited voxel resolutions. The objective of the present study is to investigate dosimetric impact of the adult MRCPs by comparing dose coefficients (DCs) calculated with the MRCPs for some external and internal exposure cases and the reference DCs in ICRP Publications 116 and 133 that were produced with the adult VRCPs. In the present study, the DCs calculated with the adult MRCPs for some exposure cases were compared with the values in ICRP Publications 116 and 133. This comparison shows that in general the MRCPs provide very similar DCs for uncharged particles, but for charged particles provide significantly different DCs due to the improvement of the MRCPs.

Comparative study of dose descriptor in pediatric computed tomography exams

International Nuclear Information System (INIS)

Finatto, Jerusa Dalbosco; Silva, Ana Maria Marques da; Froner, Ana Paula Pastre; Pimentel, Juliana

2014-01-01

This work aims to investigate the dose descriptor, volumetric Computed Tomography Dose Index (CTDI), a pediatric patients sample undergoing to skull CT, comparing the results with the diagnostic reference levels of the literature. Were collected volumetric CTDI values of all skull CT exams performed retrospectively in children of 0-10 years of age in a period of 12 months in a large hospital size. Patients, in a total of 103, were divided into four groups, where the criterion of separation used was age, trying to use the same division used in international references dose descriptors. In all acquisitions we used the pediatric protocol and the Automatic Exposure Control (AEC) available on the equipment. The CDTI values, with and without the use of AEC for pediatric studies, were compared. There was a reduction of approximately 100% in the absorbed dose value due to the use of the AEC. From the data collected and analyzed in this work, it is concluded that the use of dose reduction systems is relevant, such as the Care Dose, to maintain volumetric CTDI values within the reference levels. Also it is important the observation of range of children age to the appropriate choice of parameters used in the test protocol. The values obtained are according to the diagnostic reference levels from the literature

Radiation doses to patients from x-ray examinations - development from 2005 to 2008; Patientdoser fraan roentgenundersoekningar i Sverige - utveckling fraan 2005 till 2008

Energy Technology Data Exchange (ETDEWEB)

Leitz, Wolfram; Almen, Anja

2010-04-15

Data has been compiled and analyzed and compared with the earlier reports. Radiation doses were tested for possible links with various parameters (eg type of x-ray equipment, image recording systems, different technique factors). In conventional x-ray examinations radiation doses were, for equipment with direct digital image receivers, in average 30% lower than for those with photo plates. Mammography doses were, with one exception, the same for all types of equipment and video receivers. The CT-examinations had a small trend for higher doses for new equipment as compared to earlier. Use of exposure automation did not affect radiation doses. Compared with 2006, the doses of conventional surveys decreased by an average of 21%. One third of this dose reduction can be attributed the introduction of direct digital system whose use grew by about 30%. Most of the dose reduction can be attributed to the actions carried out to lower the dose of the reference level. Doses for the CT scan showed only a weak downwards trend. Mammography Doses decreased by an average of just over 10% a large part dependent on increased number of Sectra equipment. The system of diagnostic reference levels have again shown to have positive influence on the radiation level at the x-ray examinations, this is most pronounced for conventional radiography. There is still a large potential for dose reduction, and a measure to achieve this is to reduce the current reference levels. Very few diagnostic Standard doses are higher than the reference level. A reduction of the reference levels corresponding to the third quartile of dose distribution could lead further dose decrease of 10-20%. The corresponding reduction in dose should be done also for the DT and mammograms when lowering the reference level, there are few standard doses higher than the current reference levels

Nordic Guidance Levels for Patient Doses in Diagnostic Radiology

International Nuclear Information System (INIS)

Saxebol, G.; Olerud, H.M.; Hjardemaal, O.; Leitz, W.; Servomaa, A.; Walderhaug, T.

1998-01-01

Within the framework of Nordic authoritative cooperation in radiation protection and nuclear safety, recommendations have been prepared dealing with dose constraints in diagnostic radiology. A working group with participants from all the Nordic countries has met and discussed possible implementations of the ICRP dose constraint for medical radiology. Dose constraints, expressed as guidance levels, were specified for six different radiological examinations, i.e. chest, pelvis, lumbar spine, urography, barium meal and enema in units of kerma-area product and entrance surface dose. The recommendations are described in report No 5 in the series 'Report on Nordic Radiation Protection Cooperation'. Examples of dose distributions and factors affecting the patient dose are described in the report. (author)

Proposed man-rem reference values of occupational exposure

International Nuclear Information System (INIS)

Lombard, J.

1988-04-01

This report presents a proposal of referent collective dose (man-rem) values for occupational exposure related to operation of French pressurized water reactors. These values, permitting adequate choice of protection both at design and operation level, are dependent on the level of annual individual doses. The man-rem value, originating from annual individual doses less than 0.5 rem are estimated to 1 kf. The proposed value is 20 kf for annual individual exposures between 0.5 and 3 rem, and 90 kf for annual individual exposures between 3 and 5 rem. (author) [fr

Pediatric computed tomography dose of head and chest exams: a bibliography revision; Dose em exames de cranio e torax de tomografia computadorizada pediatrica: uma revisao bibliografica

Energy Technology Data Exchange (ETDEWEB)

Friedrich, Barbara Q.; Capaverde, Alexandre S.; Vanni, Stefania; Mazzola, Carolina F.S.; Silva, Ana M. Marques da, E-mail: barbara.friedrich@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil)

2015-08-15

The Computed Tomography (CT) imaging diagnosis it is responsible for over 34% of the radiation dose given to society, only in Brazil there is around 3833 CT equipment. There are two dose index in CT, the CTDI{sub vol} and DLP that represents the Computed Tomography dose index and the product of the CTDI{sub vol} by the length of irradiation. This paper has as objective describe the values of CTDI{sub vol} e DLP for pediatric exams of chest and head. This is an exploratory study of bibliography revision on the PubMed data base using the index terms with the following crossing: Computed Tomography AND Reference Levels AND Dose. The search was limited by published studies on the last 5 years with patients among 0 and 15 years, in English or Portuguese. Besides that, were included references guides suggest by scientific and governmental organizations on the last 5 years. The data analysis was made using the four readings of Gil: exploratory, selective, analytic and interpretative. By the Exploratory Reading were located 23 articles. On the Selective Reading were excluded 4 articles and on the Analytic Reading 9 articles. The Interpretative Reading was made using 7 publications. Regarding the references guides were includes 3 guides. The Portaria MS453/98 was included for being the only national publication. All data were characterized between practical levels and reference levels. The conclusion is that there is no consensus between the reference levels for the selected articles, for pediatric exams. Besides that, the national legislation do not have reference levels for pediatric CT. (author)

Analysis of data relative to the update of diagnosis reference levels in radiology and nuclear medicine. Situation 2004-2006

International Nuclear Information System (INIS)

2008-01-01

This report presents the results of the analysis of patients dosimetry data the radiology and nuclear medicine institutions have to transmit yearly to I.R.S.N. in application of the 12. february decree disposal relative to the diagnosis reference levels in radiology and nuclear medicine. The analysed dosimetry data concern the evaluations realised between the date of decree publication, the 16. march 2004 and 31. december 2006. The so considered results have to allow to the Nuclear Safety Authority to define the evolution needs of the regulation. Particularly, the analysis of delivered doses in radiology and the activities given in nuclear medicine lead to propositions on the possible update of reference values of some examination types. (N.C.)

Mammographic dose survey in the Czech Republic

International Nuclear Information System (INIS)

Novak, Leos; Rada, Jiri

2006-01-01

At present, it is generally accepted that the average dose to the glandular tissue is the most reasonable dose descriptor in mammography with regard to the risk of breast cancer induced by ionizing radiation. It is advantageous to use the quantity mean glandular dose M.G.D. for setting of diagnostic reference levels (D.R.L.) as well, although the quantity is not directly measurable as it is the case of D.R.L. quantities for other imaging modalities. The reason is that a directly measurable quantity suitable for mammography, incident air kerma Ki, depends a lot on a beam quality. The influence of the beam quality (expressed by tube voltage, half value layer and combination of anode/filter material) is already included in calculation of mean glandular dose. To assess a radiation burden of patients due to mammography at a national level a representative dose survey is needed to carry out. Such a study provides statistically significant dose data for setting of the national diagnostic reference levels. National Radiation Protection Institute is performing the study in the Czech Republic since the year 2005.On a basis of presented data, it could be concluded, that the situation in the Czech Republic with respect to patient doses in mammography is encouraging and that the requirements of European Commission are well fulfilled. However, it is obvious, that the obtained results can not be considered as statistically significant at the moment, because the data were not collected from a representative sample of centers, which should observe a distribution of X-ray unit types, type of a mammographic center (screening/non screening ones) and also a locality of a center. The dose survey still continues to cover the whole Czech Republic with the main task to determine new national diagnostic reference levels and to find out optimized standards for carrying out the examinations with respect to patient doses and image quality. (authors)

Mammographic dose survey in the Czech Republic

Energy Technology Data Exchange (ETDEWEB)

Novak, Leos [National Radiation Protection Institute, Prague (Czech Republic); Rada, Jiri [National Radiation Protection Institute, Ostrava (Czech Republic)

2006-07-01

At present, it is generally accepted that the average dose to the glandular tissue is the most reasonable dose descriptor in mammography with regard to the risk of breast cancer induced by ionizing radiation. It is advantageous to use the quantity mean glandular dose M.G.D. for setting of diagnostic reference levels (D.R.L.) as well, although the quantity is not directly measurable as it is the case of D.R.L. quantities for other imaging modalities. The reason is that a directly measurable quantity suitable for mammography, incident air kerma Ki, depends a lot on a beam quality. The influence of the beam quality (expressed by tube voltage, half value layer and combination of anode/filter material) is already included in calculation of mean glandular dose. To assess a radiation burden of patients due to mammography at a national level a representative dose survey is needed to carry out. Such a study provides statistically significant dose data for setting of the national diagnostic reference levels. National Radiation Protection Institute is performing the study in the Czech Republic since the year 2005.On a basis of presented data, it could be concluded, that the situation in the Czech Republic with respect to patient doses in mammography is encouraging and that the requirements of European Commission are well fulfilled. However, it is obvious, that the obtained results can not be considered as statistically significant at the moment, because the data were not collected from a representative sample of centers, which should observe a distribution of X-ray unit types, type of a mammographic center (screening/non screening ones) and also a locality of a center. The dose survey still continues to cover the whole Czech Republic with the main task to determine new national diagnostic reference levels and to find out optimized standards for carrying out the examinations with respect to patient doses and image quality. (authors)

Determination of diagnostic reference levels in general radiography in Latin America

International Nuclear Information System (INIS)

Blanco, S.; Mora, P.; Almonte, N.; Benavente, T.; Benson, N.; Blanco, D.; Cardenas, J.; Gomez, Y. D.; Edding, O.; Escobar, C.; Fonseca, M.; Gamarra, M.; Aguilar, J. G.; Khoury, H. J.; Quintero, A. R.; Zuniga, N. R.; Zaire, E.; Nader, A.

2013-01-01

The International Atomic Energy Agency (IAEA) through the International Action Plan on Radiation Protection of Patients and the International Commission on Radiological Protection have for some time carried out important efforts to assure that in the medical applications of the ionising radiations, the optimisation of radiological protection of patients is fundamental, to such a point that the IAEA includes it directly as a requirement for these practices (in its International Basic Safety Standards for Protection against Ionising Radiation and for the Safety of Radiation Sources (BSS)-GSR Part 1, 2011). For this reason, among the objectives of Regional Project RLA/9/057 and Regional Project RLA/9/067, the intention was to establish the dose references in conventional radiology for Latin America, for the purposes of determining whether these doses comply with the requirements of the BSS and to tend to improve practices, in order to minimise the dose received by the patients. (authors)

Hydroxychloroquine Blood Levels in SLE: Clarifying dosing controversies and improving adherence

Science.gov (United States)

Durcan, Laura; Clarke, William A; Magder, Laurence S.; Petri, Michelle

2015-01-01

OBJECTIVES Hydroxychloroquine is used for its effect on systemic lupus erythematosus (SLE) disease activity and long-term benefits. This can be limited by adherence. One way to assess adherence is to measure blood levels. Conflicting data exist regarding blood levels and disease activity. There is dosing controversy; rheumatologists recommend weight-based, while ophthalmologists advocate height-based ‘ideal body weight’ dosing. METHODS Patients were prescribed hydroxychloroquine not to exceed 6.5mg/kg (max400mg/day). In hemodialysis, the dose was 200mg after each session, in renal insufficiency it was 200mg/day. Levels were measured at each visit with a therapeutic range of 500-2000 ng/ml. Patients were divided according to baseline blood level. To assess the impact of measurement and counseling on adherence, we compared the proportion of patients with a level of 500ng/ml or higher based on how many prior assessments the patient had. RESULTS The proportion of patients with hydroxychloroquine levels in the therapeutic range differed significantly by age, gender and vitamin D level. There was a trend toward lower levels with renal failure. Blood levels were similar regardless of height and ideal body weight. Comparing those with undetectable, sub-therapeutic and therapeutic levels, disease activity decreased (SLEDAI 2.92, 2.36 and 2.20)(P=0.04, for trend). At first, 56% were therapeutic and by the third measurement this increased to 80% (p =hydroxychloroquine levels. Renal failure dosing led to sub-optimum levels. We show that weight-based dosing (max 400mg daily) is appropriate and that height does not appear to influence levels. Measurement, counseling and repeated testing can increase adherences rates. PMID:26428205

Pediatric chest HRCT using the iDose4 Hybrid Iterative Reconstruction Algorithm: Which iDose level to choose?

International Nuclear Information System (INIS)

Smarda, M; Alexopoulou, E; Mazioti, A; Kordolaimi, S; Ploussi, A; Efstathopoulos, E; Priftis, K

2015-01-01

Purpose of the study is to determine the appropriate iterative reconstruction (IR) algorithm level that combines image quality and diagnostic confidence, for pediatric patients undergoing high-resolution computed tomography (HRCT). During the last 2 years, a total number of 20 children up to 10 years old with a clinical presentation of chronic bronchitis underwent HRCT in our department's 64-detector row CT scanner using the iDose IR algorithm, with almost similar image settings (80kVp, 40-50 mAs). CT images were reconstructed with all iDose levels (level 1 to 7) as well as with filtered-back projection (FBP) algorithm. Subjective image quality was evaluated by 2 experienced radiologists in terms of image noise, sharpness, contrast and diagnostic acceptability using a 5-point scale (1=excellent image, 5=non-acceptable image). Artifacts existance was also pointed out. All mean scores from both radiologists corresponded to satisfactory image quality (score ≤3), even with the FBP algorithm use. Almost excellent (score <2) overall image quality was achieved with iDose levels 5 to 7, but oversmoothing artifacts appearing with iDose levels 6 and 7 affected the diagnostic confidence. In conclusion, the use of iDose level 5 enables almost excellent image quality without considerable artifacts affecting the diagnosis. Further evaluation is needed in order to draw more precise conclusions. (paper)

Alternatives to dose, quality factor and dose equivalent for low level irradiation

International Nuclear Information System (INIS)

Sondhaus, C.A.; Bond, V.P.; Feinendegen, L.E.

1988-01-01

Randomly occurring energy deposition events produced by low levels of ionizing radiation interacting with tissue deliver variable amounts of energy to the sensitive target volumes within a small fraction of the cell population. A model is described in which an experimentally derived function relating event size to cell response probability operates mathematically on the microdosimetric event size distribution characterizing a given irradiation and thus determines the total fractional number of responding cells; this fraction measures the effectiveness of the given radiation. Normalizing to equal numbers of events produced by different radiations and applying this cell response or hit size effectiveness function (HSEF) should define radiation quality, or relative effectiveness, on a more nearly absolute basis than do the absorbed dose and dose evaluation, which are confounded when applied to low level irradiations. Examples using both calculation and experimental data are presented. 15 refs., 18 figs

Reference Man for Asians as well as for Europeans-A change in the ICRP concept of Reference Man

International Nuclear Information System (INIS)

Tanaka, Gi-ichiro

1990-01-01

ICRP Reference Man, according to the definition, is primarily for Caucasoid populations (Western Europeans and North Americans) that contribute only 13 per cent of the world population. A speculative world population dose will, assuming a uniform exposure all over the world at a level of 10 μSv, be 50 k man Sv in total. Of this, all regions of Caucasoid populations may contribute by 22 per cent maximum. Asian populations will share about 58 per cent (29 k man Sv) of the world population dose. About eighty per cents in total of the world population can be convered by scientific dose assessment, if Reference Man data for Asians are made available. Thus the importance of establishing Asian Reference Man should be evident. The important point of characteristics of Asians is that they are 'Vegetarians' as compared to Westerners, which suggests different pathways with respect to transfer of radionuclides from foods to the human body. Therefore it is required to determine accurate and suitable parameters relevant to dose assessment. Considering the above, contribution of Japan in science and technology to Asian countries with 'knowhows' accumulated may be of a most urgent matter. (author)

The establishment of local diagnostic reference levels in endoscopic retrograde cholangiopancreatography: a practical tool for the optimisation and for quality assurance management

International Nuclear Information System (INIS)

Saukko, E.; Henner, A.; Nieminen, M.T.; Ahonen, S.-M.

2017-01-01

Fluoroscopic procedures are an area of special concern in relation to radiation protection. The aim of this study was to describe the current level of patient radiation doses in endoscopic retrograde cholangiopancreatography (ERCP) collected from a single centre, as well as to establish and review local diagnostic reference levels (DRLs) in ERCP. A total of 100 patients' radiation doses in ERCP were recorded, and the third-quartile method was adopted to establish local DRLs for ERCP. The mean dose area product (DAP) was 2.05 Gy cm 2 , fluoroscopy time (FT) 1.7 min and the number of images was 3. The proposed local DRLs for ERCP were 3.00 Gy cm 2 and 3.0 min. Local DRLs were reviewed in a sample of 25 patients 5 y after they had been established. In reviewing data, the averages of DAP and FT were below the local DRLs. Local DRLs help in the optimisation process of fluoroscopic procedures and guides to a good clinical practice. (authors)

Dose-response relationships and threshold levels in skin and respiratory allergy

NARCIS (Netherlands)

Arts, J.H.E.; Mommers, C.; Heer, C.de

2006-01-01

A literature study was performed to evaluate dose-response relationships and no-effect levels for sensitization and elicitation in skin- and respiratory allergy. With respect to the skin, dose-response relationships and no-effect levels were found for both intradermal and topical induction, as well

Diagnostic reference levels and complexity indices in interventional radiology: a national programme

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Cruces, R.; Perez-Martinez, M.; Pastor-Vega, J.M.; Canete, S. [University of Malaga, School of Medicine, Malaga (Spain); Vano, E.; Fernandez-Soto, J.M.; Sanchez-Casanueva, R.; Gallego-Beuter, J.J. [Complutense University, San Carlos Hospital, Medical School, Madrid (Spain); Carrera-Magarino, F.; Moreno-Rodriguez, F.; Moreno-Sanchez, T. [Juan Ramon Jimenez University Hospital, Huelva (Spain); Soler-Cantos, M.M.; Canis-Lopez, M. [Reina Sofia University Hospital, Cordoba (Spain); Hernandez-Armas, J.; Diaz-Romero, F.J. [University Hospital of Canary Islands, Tenerife (Spain); Rosales-Espizua, F.; Lopez-Medina, A.; Gonzalez-de-Garay, M. [Basurto Hospital, Bilbao (Spain); Martin-Palanca, A. [Virgen de la Victoria University Hospital, Malaga (Spain); Gil-Agudo, A.; Zarca-Diaz, M.A.; Zapata-Jimenez, J.C. [General University Hospital, Ciudad Real (Spain); Parra-Osorio, V.; Munoz Ruiz-Canela, J.J.; Moreno-Saiz, C.; Galan-Montenegro, P. [Carlos Haya University Hospital, Malaga (Spain)

2016-12-15

To propose national diagnostic reference levels (DRLs) for interventional radiology and to evaluate the impact of the procedural complexity on patient doses. Eight interventional radiology units from Spanish hospitals were involved in this project. The participants agreed to undergo common quality control procedures for X-ray systems. Kerma area product (KAP) was collected from a sample of 1,649 procedures. A consensus document established the criteria to evaluate the complexity of seven types of procedures. DRLs were set as the 3rd quartile of KAP values. The KAP (3rd quartile) in Gy cm{sup 2} for the procedures included in the survey were: lower extremity arteriography (n = 784) 78; renal arteriography (n = 37) 107; transjugular hepatic biopsies (THB) (n = 30) 45; biliary drainage (BD) (n = 314) 30; uterine fibroid embolization (UFE) (n = 56) 214; colon endoprostheses (CE) (n = 31) 169; hepatic chemoembolization (HC) (n = 269) 303; femoropopliteal revascularization (FR) (n = 62) 119; and iliac stent (n = 66) 170. The complexity involved the increases in the following KAP factors from simple to complex procedures: THB x4; BD x13; UFE x3; CE x3; HC x5; FR x5 and IS x4. The evaluation of the procedure complexity in patient doses will allow the proper use of DRLs for the optimization of interventional radiology. (orig.)

Reference computations of public dose and cancer risk from airborne releases of uranium and Class W plutonium

International Nuclear Information System (INIS)

Peterson, V.L.

1995-01-01

This report presents ''reference'' computations that can be used by safety analysts in the evaluations of the consequences of postulated atmospheric releases of radionuclides from the Rocky Flats Environmental Technology Site. These computations deal specifically with doses and health risks to the public. The radionuclides considered are Class W Plutonium, all classes of Enriched Uranium, and all classes of Depleted Uranium. (The other class of plutonium, Y, was treated in an earlier report.) In each case, one gram of the respirable material is assumed to be released at ground leveL both with and without fire. The resulting doses and health risks can be scaled to whatever amount of release is appropriate for a postulated accident being investigated. The report begins with a summary of the organ-specific stochastic risk factors appropriate for alpha radiation, which poses the main health risk of plutonium and uranium. This is followed by a summary of the atmospheric dispersion factors for unfavorable and typical weather conditions for the calculation of consequences to both the Maximum Offsite Individual and the general population within 80 km (50 miles) of the site

Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

International Nuclear Information System (INIS)

Williamson, Jeffrey F.

1997-01-01

Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume -- Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) -- Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

Physics and quality assurance for brachytherapy - Part II: Low dose rate and pulsed dose rate

International Nuclear Information System (INIS)

Williamson, Jeffrey F.

1996-01-01

Purpose: A number of recent developments have revitalized brachytherapy including remote afterloading, implant optimization, increasing use of 3D imaging, and advances in dose specification and basic dosimetry. However, the core physical principles underlying the classical methods of dose calculation and arrangement of multiple sources remain unchanged. The purpose of this course is to review these principles and their applications to low dose-rate interstitial and intracavitary brachytherapy. Emphasis will be placed upon the classical implant systems along with classical and modern methods of dose specification. The level of presentation is designed for radiation oncology residents and beginning clinical physicists. A. Basic Principles (1) Radium-substitute vs. low-energy sealed sources (2) Dose calculation principles (3) The mysteries of source strength specification revealed: mgRaEq, mCi and air-kerma strength B. Interstitial Brachytherapy (1) Target volume, implanted volume, dose specification in implants and implant optimization criteria (2) Classical implant systems: Manchester Quimby and Paris a) Application of the Manchester system to modern brachytherapy b) Comparison of classical systems (3) Permanent interstitial implants a) Photon energy and half life b) Dose specification and pre-operative planning (4) The alphabet soup of dose specification: MCD (mean central dose), minimum dose, MPD (matched peripheral dose), MPD' (minimum peripheral dose) and DVH (dose-volume histogram) quality indices C. Intracavitary Brachytherapy for Carcinoma of the Cervix (1) Basic principles a) Manchester System: historical foundation of U.S. practice patterns b) Principles of applicator design (2) Dose specification and treatment prescription a) mg-hrs, reference points, ICRU Report 38 reference volume --Point A dose vs mg-hrs and IRAK (Integrated Reference Air Kerma) --Tissue volume treated vs mg-hrs and IRAK b) Practical methods of treatment specification and prescription

Development of a Reference System for the determination of the personal dose equivalent and the constancy of X- Ray beams

International Nuclear Information System (INIS)

Vivolo, Vitor

2006-01-01

A reference system for the determination of the personal dose equivalent, Hp (10), and a quality control program of X-ray equipment used In radioprotection require the periodic verification of the X-ray beams constancy. In this work, two parallel-plate ionization chambers were developed with inner electrodes of different materials, and inserted into PMMA slab phantoms. One ionization chamber was developed with inner carbon electrodes and the other with inner aluminium electrodes. The two ionization chambers can be used as a Tandem system. The different energy response of the two ionization chambers allowed the development of the Tandem system that is very useful for the checking of the constancy of beam qualities. Standard intermediary energy X-ray beams (from 48 keV to 118 keV), radioprotection level, were established through the development of a dosimetric methodology and the analysis of their physical parameters. The ionization chambers were studied in relation to their operational characteristics, and they were calibrated in X-ray beams (radioprotection, diagnostic radiology, mammography and radiotherapy levels) in accordance to international recommendations. They presented good performance. The determination procedure of personal dose equivalent, Hp (10), was established. (author)

Survey of pediatric MDCT radiation dose from university hospitals in Thailand. A preliminary for national dose survey

Energy Technology Data Exchange (ETDEWEB)

Kritsaneepaiboon, Supika [Dept. of Radiology, Faculty of Medicine, Prince of Songkla Univ., Hat Yai (Thailand)], e-mail: supikak@yahoo.com; Trinavarat, Panruethai [Dept. of Radiology, Faculty of Medicine, Chulalongkorn Univ., Bangkok (Thailand); Visrutaratna, Pannee [Dept. of Radiology, Faculty of Medicine, Chiang Mai Univ., Chiang Mai (Thailand)

2012-09-15

Background: Increasing pediatric CT usage worldwide needs the optimization of CT protocol examination. Although there are previous published dose reference level (DRL) values, the local DRLs should be established to guide for clinical practice and monitor the CT radiation. Purpose: To determine the multidetector CT (MDCT) radiation dose in children in three university hospitals in Thailand in four age groups using the CT dose index (CTDI) and dose length product (DLP). Material and Methods: A retrospective review of CT dosimetry in pediatric patients (<15 years of age) who had undergone head, chest, and abdominal MDCT in three major university hospitals in Thailand was performed. Volume CTDI (CTDIvol) and DLP were recorded, categorized into four age groups: <1 year, 1- < 5 years, 5- <10 years, and 10- <15 years in each scanner. Range, mean, and third quartile values were compared with the national reference dose levels for CT in pediatric patients from the UK and Switzerland according to International Commission on Radiological Protection (ICRP) recommendation. Results: Per age group, the third quartile values for brain, chest, and abdominal CTs were, respectively, in terms of CTDIvol: 25, 30, 40, and 45 mGy; 4.5, 5.7, 10, and 15.6 mGy; 8.5, 9, 14, and 17 mGy; and in terms of DLP: 400, 570, 610, and 800 mGy cm; 80, 140, 305, and 470 mGy cm; and 190, 275, 560,765 mGy cm. Conclusion: This preliminary national dose survey for pediatric CT in Thailand found that the majority of CTDIvol and DLP values in brain, chest, and abdominal CTs were still below the diagnostic reference levels (DRLs) from the UK and Switzerland regarding to ICRP recommendation.

Pediatric computed tomography dose of head and chest exams: a bibliography revision

International Nuclear Information System (INIS)

Friedrich, Barbara Q.; Capaverde, Alexandre S.; Vanni, Stefania; Mazzola, Carolina F.S.; Silva, Ana M. Marques da

2015-01-01

The Computed Tomography (CT) imaging diagnosis it is responsible for over 34% of the radiation dose given to society, only in Brazil there is around 3833 CT equipment. There are two dose index in CT, the CTDI vol and DLP that represents the Computed Tomography dose index and the product of the CTDI vol by the length of irradiation. This paper has as objective describe the values of CTDI vol e DLP for pediatric exams of chest and head. This is an exploratory study of bibliography revision on the PubMed data base using the index terms with the following crossing: Computed Tomography AND Reference Levels AND Dose. The search was limited by published studies on the last 5 years with patients among 0 and 15 years, in English or Portuguese. Besides that, were included references guides suggest by scientific and governmental organizations on the last 5 years. The data analysis was made using the four readings of Gil: exploratory, selective, analytic and interpretative. By the Exploratory Reading were located 23 articles. On the Selective Reading were excluded 4 articles and on the Analytic Reading 9 articles. The Interpretative Reading was made using 7 publications. Regarding the references guides were includes 3 guides. The Portaria MS453/98 was included for being the only national publication. All data were characterized between practical levels and reference levels. The conclusion is that there is no consensus between the reference levels for the selected articles, for pediatric exams. Besides that, the national legislation do not have reference levels for pediatric CT. (author)

Development of a Reference Dose for Perchlorate: Current Issues and Status

Science.gov (United States)

Pleus, R. C.; Goodman, G.; Mattie, D. R.

2000-01-01

The perchlorate anion (ClO4) is typically manufactured as the ammonium salt. The most common use of ammonium perchlorate is in the aerospace program as a component of solid rocket fuel. The perchlorate anion is exceedingly stable under environmental conditions and has been found in ground and surface waters in CA, NV, UT, AZ, TX, AK, NY, MD, WV and FL. The National Center for Environmental Assessment (NCEA) of the U.S. Environmental Protection Agency (US EPA) is in the process of developing an oral reference dose (RfD) for perchlorate. An oral RfD is a body-weight-adjusted dose that can be consumed daily over an entire lifetime with the expectation of no adverse health effects. Once developed, the new RfD will be used by US EPA as the basis of a safe-drinking-water level (SDWL) guideline. US EPA and regional regulatory agencies will then jointly or separately propose clean-up action levels for ground and surface waters at contaminated sites. The toxicological database on CIO4- as of March 1997 was determined by an expert peer-review panel to be inadequate for the purpose of deriving an oral RfD. For example, little or no experimental data existed on the subchronic, reproductive, or developmental toxicity of perchlorate. To fill gaps in the toxicological database, eight animal studies were designed by a government-industry consortium that included US EPA and AFRL. These studies were performed in 1997-1998. It has been known for many years that in the thyroid, high doses of perchlorate block the function of iodide by competing for iodide binding sites. Perchlorate was used in the 1950s-60s as a treatment for Graves' disease (a hyperthyroid condition). Because of what was already known about the pharmacological mode of action of perchlorate, specific concerns addressed in the design of the recent animal studies included the potential for developmental toxicity, notably neurological development. Upon review of complete study reports from four of the studies and

MO-FG-CAMPUS-IeP1-03: Establishment of Provincial Diagnostic Reference Levels in Pediatric Imaging

International Nuclear Information System (INIS)

Tonkopi, E; O’Brien, K

2016-01-01

Purpose: To establish provincial diagnostic reference levels (DRLs) in pediatric general radiography and computed tomography (CT) as a tool for the optimization of exposure parameters. Methods: Patient dose survey was conducted in the only pediatric hospital in the province of Nova Scotia. The DRLs were established as the 75th percentile of patient dose distributions in different age groups. For routine radiography projections the DRLs were determined in terms of entrance surface dose (ESD) calculated from the radiation output measurements and the tube current-exposure time product (mAs) recorded for each examination. Patient thickness was measured by the technologist during the examination. The CR and DR systems, employing respectively a fixed technique and phototiming, were evaluated separately; a two-tailed Student’s t-test was used to determine the significance of differences between the means of dose distributions. The CT studies included routine head, chest, abdomen/pelvis, and chest/abdomen/pelvis. The volume CT dose index (CTDIvol) and dose-length product (DLP) values were extracted retrospectively from PACS. The correction factors based on the effective diameter of the patient were applied to the CT dosimetry metrics based on the standard phantoms. Results: The provincial DRLs were established in the following age groups: newborn, 1, 5, 10, and 15 year olds. In general radiography the DR systems demonstrated slightly lower dose than the CR for all views, however the differences were not statistically significant (p > 0.05) for all examinations. In CT the provincial DRLs were lower than the published data, except for head DLPs in all age categories. This might be due to the small patient sample size in the survey. Future work will include additional CT data collection over an extended period of time. Conclusion: Provincial DRLs were established in the dedicated children’s hospital to provide guidance for the other facilities in examinations of pediatric

MO-FG-CAMPUS-IeP1-03: Establishment of Provincial Diagnostic Reference Levels in Pediatric Imaging

Energy Technology Data Exchange (ETDEWEB)

Tonkopi, E [Dalhousie University (Canada); Queen Elizabeth II Health Sciences Ctr (Canada); O’Brien, K [Dalhousie University (Canada); IWK Health Centre, Halifax, NS (Canada)

2016-06-15

Purpose: To establish provincial diagnostic reference levels (DRLs) in pediatric general radiography and computed tomography (CT) as a tool for the optimization of exposure parameters. Methods: Patient dose survey was conducted in the only pediatric hospital in the province of Nova Scotia. The DRLs were established as the 75th percentile of patient dose distributions in different age groups. For routine radiography projections the DRLs were determined in terms of entrance surface dose (ESD) calculated from the radiation output measurements and the tube current-exposure time product (mAs) recorded for each examination. Patient thickness was measured by the technologist during the examination. The CR and DR systems, employing respectively a fixed technique and phototiming, were evaluated separately; a two-tailed Student’s t-test was used to determine the significance of differences between the means of dose distributions. The CT studies included routine head, chest, abdomen/pelvis, and chest/abdomen/pelvis. The volume CT dose index (CTDIvol) and dose-length product (DLP) values were extracted retrospectively from PACS. The correction factors based on the effective diameter of the patient were applied to the CT dosimetry metrics based on the standard phantoms. Results: The provincial DRLs were established in the following age groups: newborn, 1, 5, 10, and 15 year olds. In general radiography the DR systems demonstrated slightly lower dose than the CR for all views, however the differences were not statistically significant (p > 0.05) for all examinations. In CT the provincial DRLs were lower than the published data, except for head DLPs in all age categories. This might be due to the small patient sample size in the survey. Future work will include additional CT data collection over an extended period of time. Conclusion: Provincial DRLs were established in the dedicated children’s hospital to provide guidance for the other facilities in examinations of pediatric

Low level dose induced chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Pohl-Rueling, J.

1992-01-01

Unstable structural aberrations in chromosomes of human blood lymphocytes cannot be used as biological dosemeters in the low dose range, when extrapolating from high doses using a linear dose response, as required by the original formula of the dual radiation action theory. A survey is given of experimental dose-response curves of chromosome aberrations, obtained in investigations not only by this institute, in cooperation with many other laboratories, but also by various authors in different areas of the world. The results are not compatible with the predicted linear dose relationships at in vivo dose ranges up to 30 mGy.y -1 . The aberration frequencies rise sharply with dose within the normal environmental exposure up to about twice that level. At higher doses, aberration frequencies increase less rapidly and reach a plateau. Some in vitro experiments of various authors with higher doses of low LET radiations, up to about 400 mGy have found dose responses with steps. (author)

Dose assessment in pediatric computerized tomography; Avaliacao de doses em tomografia computadorizada pediatrica

Energy Technology Data Exchange (ETDEWEB)

Vilarinho, Luisa Maria Auredine Lima

2004-07-01

The objective of this work was the evaluation of radiation doses in paediatric computed tomography scans, considering the high doses usually involved and the absence of any previous evaluation in Brazil. Dose values were determined for skull and abdomen examinations, for different age ranges, by using the radiographic techniques routinely used in the clinical centers investigated. Measurements were done using pencil shape ionization chambers inserted in polymethylmethacrylate (PMMA) phantoms. These were compact phantoms of different diameters were specially designed and constructed for this work, which simulate different age ranges. Comparison of results with published values showed that doses were lower than the diagnostic reference levels established to adults exams by the European Commission. Nevertheless, doses in paediatric phantoms were higher than those obtained in adult phantoms. The paediatric dose values obtained in Hospitals A and B were lower than the reference level (DRL) adopted by SHIMPTON for different age ranges. In the range 0 - 0.5 year (neonatal), the values of DLP in Hospital B were 94 por cent superior to the DRL For the 10 years old children the values of CTDI{sub w} obtained were inferior in 89 por cent for skull and 83 por cent for abdomen examinations, compared to the values published by SHRIMPTON and WALL. Our measured CTDI{sub w} values were inferior to the values presented for SHRIMPTON and HUDA, for all the age ranges and types of examinations. It was observed that the normalized dose descriptors values in children in the neonatal range were always superior to the values of doses for the adult patient. In abdomen examinations, the difference was approximately 90% for the effective dose (E) and of 57%.for CTDI{sub w} . (author)

Bioequivalence of fixed-dose combination Myrin®-P Forte and reference drugs in loose combination.

Science.gov (United States)

Wang, H F; Wang, R; O'Gorman, M; Crownover, P; Naqvi, A; Jafri, I

2013-12-01

Myrin®-P Forte is a fixed-dose combination (FDC) tablet containing rifampicin (RMP, 150 mg), isoniazid (INH, 75 mg), ethambutol (EMB) hydrochloride (275 mg) and pyrazinamide (PZA, 400 mg) developed for the treatment of tuberculosis (TB). This study was conducted at a single centre--the Pfizer Clinical Research Unit in Singapore. To demonstrate the bioequivalence of each drug component of the Myrin-P Forte FDC and the individual product in loose combination. In a randomized, open-label, single-dose, two-way, crossover study, subjects received single doses of Myrin-P Forte or four individual products under fasting conditions in a crossover fashion with at least 7 days washout between doses. The primary measures for comparison were peak plasma concentration (C(max)) and the area under plasma concentration-time curve (AUC). Of 36 subjects enrolled, 35 completed the study. The adjusted geometric mean ratios and 90% confidence intervals for C(max) and AUC values were completely contained within bioequivalence limits (80%, 125%) for all four drugs in both formulations. Both treatments were generally well tolerated in the study. The Myrin-P Forte FDC tablet formulation is bioequivalent to the four single-drug references for RMP, INH, EMB hydrochloride and PZA at equivalent doses.

Reference dosimetry for CT in the UK

International Nuclear Information System (INIS)

Shrimpton, P.C.; Wall, B.F.

2001-01-01

Computed tomography is firmly established as a major source of population exposure from diagnostic x-ray examinations and thus a particular focus for radiological protection initiatives. The concept of reference doses is widely recognised as a useful and practical tool for promoting improvements in the optimisation of protection for patients undergoing radiological examinations. National diagnostic reference levels (DRLs) have already been successfully applied in the UK for some conventional x-ray examinations within a framework for advice on patient protection. This approach is being extended to include CT, utilising the robust methodology for reference dosimetry that has been developed by the European Commission (EC) for the particular conditions of exposure in CT. This is based on the dosimetric concepts of weighted computed tomography dose index (CTDI w ) per slice in serial scanning or per rotation in helical scanning, and dose-length product (DLP) per complete examination. Notwithstanding some initial values proposed by the EC, specific national DRLs for CT practice in the UK will be established on the basis of widescale national survey data. (author)

The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography

International Nuclear Information System (INIS)

Santos, Joana; Paulo, Graciano; Foley, Shane; Rainford, Louise; McEntee, Mark F.

2015-01-01

The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings. (orig.)

The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography

Energy Technology Data Exchange (ETDEWEB)

Santos, Joana; Paulo, Graciano [Instituto Politecnico de Coimbra, ESTESC, DMIR, Coimbra (Portugal); Foley, Shane; Rainford, Louise [University College Dublin, School of Medicine and Medical Science, Health Science Centre, Dublin 4 (Ireland); McEntee, Mark F. [The University of Sydney, Faculty of Health Sciences, Cumberland Campus, Sydney (Australia)

2015-11-15

The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings. (orig.)

Establishment of local Diagnostic Reference Levels (DRLs) for ...

African Journals Online (AJOL)

Diagnostic reference levels (DRLs) is an essential optimization tool in radiography and radiological sciences. The objective of the study is to establish DRL for radiography examinations in north eastern Nigeria. A Prospective cross- sectional study conducted in two university teaching hospitals in north eastern Nigeria.

Establishing a reference range for triiodothyronine levels in preterm infants.

Science.gov (United States)

Oh, Ki Won; Koo, Mi Sung; Park, Hye Won; Chung, Mi Lim; Kim, Min-ho; Lim, Gina

2014-10-01

Thyroid dysfunction affects clinical complications in preterm infants and older children. However, thyroid hormone replacement in preterm infants has no proven benefits, possibly owing to the lack of an appropriate reference range for thyroid hormone levels. We aimed to establish a reference range for triiodothyronine (T3) levels at 1-month postnatal age (PNA) in preterm infants. This retrospective study included preterm infants born at a tertiary referral neonatal center at gestational age (GA)<35 weeks with no apparent thyroid dysfunction, for 6 consecutive years, with follow-up from PNA 2 weeks to 16 weeks. Using thyroid function tests (TFT), the relationships between T3 levels and thyrotropin (TSH) and free thyroxine (fT4) levels, birth weight, GA, postmenstrual age (PMA), and PNA were examined. The conversion trend for fT4 to T3 was analyzed using the T3/fT4 ratio. Overall, 464 TFTs from 266 infants were analyzed, after excluding 65 infants with thyroid dysfunction. T3 levels increased with fT4 levels, birth weight, GA, PMA, and PNA but not with TSH levels. The T3/fT4 ratio also increased with GA, PNA, and PMA. The average T3 level at 1 month PNA was 72.56 ± 27.83 ng/dL, with significant stratifications by GA. Relatively low T3 and fT4 levels in preterm infants were considered normal, with T3 levels and conversion trends increasing with GA, PMA, and PNA. Further studies are required to confirm the role of the present reference range in thyroid hormone replacement therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Survey of patient dose in computed tomography in Syria 2009.

Science.gov (United States)

Kharita, M H; Khazzam, S

2010-09-01

The radiation doses to patient in computed tomography (CT) in Syria have been investigated and compared with similar studies in different countries. This work surveyed 30 CT scanners from six different manufacturers distributed all over Syria. Some of the results in this paper were part of a project launched by the International Atomic Energy Agency in different regions of the world covering Asia, Africa and Eastern Europe. The dose quantities covered are CT dose index (CTDI(w)), dose-length product (DLP), effective dose (E) and collective dose. It was found that most CTDI(w) and DLP values were similar to the European reference levels and in line with the results of similar surveys in the world. The results were in good agreement with the UNSCEAR Report 2007. This study concluded a recommendation for national diagnostic reference level for the most common CT protocols in Syria. The results can be used as a base for future optimisation studies in the country.

Dose Calculation Evolution for Internal Organ Irradiation in Humans

International Nuclear Information System (INIS)

Jimenez V, Reina A.

2007-01-01

The International Commission of Radiation Units (ICRU) has established through the years, a discrimination system regarding the security levels on the prescription and administration of doses in radiation treatments (Radiotherapy, Brach therapy, Nuclear Medicine). The first level is concerned with the prescription and posterior assurance of dose administration to a point of interest (POI), commonly located at the geometrical center of the region to be treated. In this, the effects of radiation around that POI, is not a priority. The second level refers to the dose specifications in a particular plane inside the patient, mostly the middle plane of the lesion. The dose is calculated to all the structures in that plane regardless if they are tumor or healthy tissue. In this case, the dose is not represented by a point value, but by level curves called 'isodoses' as in a topographic map, so you can assure the level of doses to this particular plane, but it also leave with no information about how this values go thru adjacent planes. This is why the third level is referred to the volumetrical description of doses so these isodoses construct now a volume (named 'cloud') that give us better assurance about tissue irradiation around the volume of the lesion and its margin (sub clinical spread or microscopic illness). This work shows how this evolution has resulted, not only in healthy tissue protection improvement but in a rise of tumor control, quality of life, better treatment tolerance and minimum permanent secuelae

High dose rate (HDR) and low dose rate (LDR) interstitial irradiation (IRT) of the rat spinal cord

International Nuclear Information System (INIS)

Pop, Lucas A.M.; Plas, Mirjam van der; Skwarchuk, Mark W.; Hanssen, Alex E.J.; Kogel, Albert J. van der

1997-01-01

Purpose: To describe a newly developed technique to study radiation tolerance of rat spinal cord to continuous interstitial irradiation (IRT) at different dose rates. Material and methods: Two parallel catheters are inserted just laterally on each side of the vertebral bodies from the level of Th 10 to L 4 . These catheters are afterloaded with two 192 Ir wires of 4 cm length each (activity 1-2.3 mCi/cm) for the low dose rate (LDR) IRT or connected to the HDR micro-Selectron for the high dose rate (HDR) IRT. Spinal cord target volume is located at the level of Th 12 -L 2 . Due to the rapid dose fall-off around the implanted sources, a dose inhomogeneity across the spinal cord thickness is obtained in the dorso-ventral direction. Using the 100% reference dose (rate) at the ventral side of the spinal cord to prescribe the dose, experiments have been carried out to obtain complete dose response curves at average dose rates of 0.49, 0.96 and 120 Gy/h. Paralysis of the hind-legs after 5-6 months and histopathological examination of the spinal cord of each irradiated rat are used as experimental endpoints. Results: The histopathological damage seen after irradiation is clearly reflected the inhomogeneous dose distribution around the implanted catheters, with the damage predominantly located in the dorsal tract of the cord or dorsal roots. With each reduction in average dose rate, spinal cord radiation tolerance is significantly increased. When the dose is prescribed at the 100% reference dose rate, the ED 50 (induction of paresis in 50% of the animals) for the HDR-IRT is 17.3 Gy. If the average dose rate is reduced from 120 Gy/h to 0.96 or 0.49 Gy/h, a 2.9- or 4.7-fold increase in the ED 50 values to 50.3 Gy and 80.9 Gy is observed; for the dose prescribed at the 150% reference dose rate (dorsal side of cord) ED 50 values are 26.0, 75.5 and 121.4 Gy, respectively. Using different types of analysis and in dependence of the dose prescription and reference dose rate, the �

Cosmic radiation doses at flight level altitudes of airliners

International Nuclear Information System (INIS)

Viragh, E.; Petr, I.

1985-01-01

Changes are discussed in flux density of cosmic radiation particles with time as are the origin of cosmic radiation, the level of cosmic radiation near the Earth's surface, and the determination of cosmic radiation doses in airliners. Doses and dose rates are given measured on different flight routes. In spite of the fact that the flight duration at an altitude of about 10 km makes for about 80% of the total flight time, the overall radiation burden of the crews at 1000 flight hours a year is roughly double that of the rest of the population. (J.C.)

PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION

Energy Technology Data Exchange (ETDEWEB)

J.A. Ziegler

2000-11-20

The purpose of this calculation is to provide a dose consequence analysis of high-level waste (HLW) consisting of plutonium immobilized in vitrified HLW to be handled at the proposed Monitored Geologic Repository at Yucca Mountain for a beyond design basis event (BDBE) under expected conditions using best estimate values for each calculation parameter. In addition to the dose calculation, a plutonium respirable particle size for dose calculation use is derived. The current concept for this waste form is plutonium disks enclosed in cans immobilized in canisters of vitrified HLW (i.e., glass). The plutonium inventory at risk used for this calculation is selected from Plutonium Immobilization Project Input for Yucca Mountain Total Systems Performance Assessment (Shaw 1999). The BDBE examined in this calculation is a nonmechanistic initiating event and the sequence of events that follow to cause a radiological release. This analysis will provide the radiological releases and dose consequences for a postulated BDBE. Results may be considered in other analyses to determine or modify the safety classification and quality assurance level of repository structures, systems, and components. This calculation uses best available technical information because the BDBE frequency is very low (i.e., less than 1.0E-6 events/year) and is not required for License Application for the Monitored Geologic Repository. The results of this calculation will not be used as part of a licensing or design basis.

Evaluation of patient radiation doses using DAP meter in interventional radiology procedures

Energy Technology Data Exchange (ETDEWEB)

Kang, Byung Sam [Dept. of Radiological Technology. Shingu University, Sungnam (Korea, Republic of); Yoon, Yong Su [Dept. of Health Sciences, Graduate School of Medical Sciences, Kyushu Univeristy, Kyushu (Japan)

2017-03-15

The author investigated interventional radiology patient doses in several other countries, assessed accuracy of DAP meters embedded in intervention equipment in domestic country, conducted measurement of patient doses for 13 major interventional procedures with use of Dose Area Product(DAP) meters from 23 hospitals in Korea, and referred to 8,415 cases of domestic data related to interventional procedures by radiation exposure after evaluation the actual effective of dose reduction variables through phantom test. Finally, dose reference level for major interventional procedures was suggested. In this study, guidelines for patient doses were 237.7 Gy·cm{sup 2} in TACE, 17.3 Gy·cm{sup 2} in AVF, 114.1 Gy·cm{sup 2} in LE PTA and STENT, 188.5 Gy·cm{sup 2} in TFCA, 383.5 Gy·cm{sup 2} in Aneurysm Coil, 64.6 Gy·cm{sup 2} in PTBD, 64.6 Gy·cm{sup 2} in Biliary Stent, 22.4 Gy·cm{sup 2} in PCN, 4.3 Gy·cm{sup 2} in Hickman, 2.8 Gy·cm{sup 2} in Chemo-port, 4.4 Gy·cm{sup 2} in Perm-Cather, 17.1 Gy·cm{sup 2} in PCD, and 357.9 Gy·cm{sup 2} in Vis, EMB. Dose reference level acquired in this study is considered to be able to use as minimal guidelines for reducing patient dose in the interventional radiology procedures. For the changes and advances of materials and development of equipment and procedures in the interventional radiology procedures, further studies and monitoring are needed on dose reference level Korean DAP dose conversion factor for the domestic procedures.

Study on the setting of Reference Chinese man

International Nuclear Information System (INIS)

Wang Jixian; Chen Rusong

1998-01-01

The procedures for internal and external dose estimation, the calculation of authorized limits and derived reference levels, and the development of phantoms in the field of radiation protection are based on values for the ICRP Reference Man. Many differences exist between Asians, Europeans and North Americans with respect to race, customs and the pattern of food consumption. The neglect of these differences in the parameters used may lead to errors in dose assessment and health effect prognosis. research described in this paper was conducted to obtain reference values for the Chinese population or other Asian countries which might have major demographic contribution of Chinese. Based on the agreements reached in the Project Formulation Meeting ''Compilation of Anatomical, Physiological and Metabolic Characteristics for a Reference Asian Man'', the measurement of physique, organ mass and the food consumption were given the first priority for the first phase of the project. (author)

Determination of dose to patient in different teams of TC and assessment with international reference levels; Determinacion de dosis a pacientes en diferentes equipos de TC y evaluacion con niveles de referencia internacionales

Energy Technology Data Exchange (ETDEWEB)

Ruiz Morales, C.; Fernandez lara, A. A.; Buades Forner, M. J.; Tobarra Gonzalez, B. M.

2013-07-01

The increase in CT studies and the differences observed between the different equipment used in our hospital prompted us to determine the doses to patients in different studies and check the results obtained with the reference values published internationally. (Author)

Radiation Dose Contribution To The Worker Health Level At Serpong Area

International Nuclear Information System (INIS)

Yuwono, Indro

2000-01-01

Analysis of internal and external radiation doses received for radiation and non-radiation workers of P2TBDU have been done. In the period of 1997/1998 and 1998/1999 there were no significant increasing level of radiation doses received that was 0.55 mSv and highest received radiation dose was 2.66% from dose limit value. Increasing of healthy difference on the same period was 5.76%. Increasing of healthy difference no cause by increasing of radiation dose received but maybe the food consumption design

The calculation of dose from photon exposures using reference human phantoms and Monte Carlo methods. Pt. 5

International Nuclear Information System (INIS)

Petoussi, N.; Zankl, M.; Williams, G.; Veit, R.; Drexler, G.

1987-01-01

There has been some evidence that cervical cancer patients who were treated by radiotherapy, had an increased incidence of second primary cancers noticeable 15 years or more after the radiotherapy. The data suggested that high dose pelvic irradiation was associated with increase in cancers of the bladder, kidneys, rectum, ovaries, corpus uteri, and non-Hodgkin's lymphoma but not leukemia (Kleinerman et al., 1982, Morton 1973). The aim of the present work is to estimate the absorbed dose, due to radiotherapy treatment for cervival cancer, to various organs and tissues in the body. Monte Carlo calculations were performed to calculate the organ absorbed doses resulting from intracavitary sources such as ovoids and applicators filled or loaded with radium, Co-60 and Cs-137. For that purpose a routine which simulates an internal source was constructed and added to the existing Monte Carlo code (GSF-Bericht S-885, Kramer et al.). Calculations were also made for external beam therapy. Various anterior, posterior and lateral fields were applied, resulting from megavoltage, Co-60 and Cs-137 therapy machines. The calculated organ doses are tabulated in three different ways: as organ dose per air Kerma in the reference field, according to the recommendations of the International Commission on Radiation Units and Measurements (ICRU Report No 38, 1985); as organ dose per surface dose and as organ dose per tissue dose at Point B. (orig.)

Diagnostic reference levels for X-ray investigations in pain management units in Belgium

International Nuclear Information System (INIS)

Lichtherte, S.; Le Polain de Waroux, B.

2008-01-01

X-rays are commonly used in pain treatment centres where infiltrative techniques are performed. Although X-rays are useful in increasing the precision of infiltrative techniques, their use puts patients and staff at risk of radiation exposure. As a result, medical staff now have to obtain a certificate of training on the use of X-rays before being allowed to use X-rays in practice. This analysis was based on 373 detailed registrations of procedure-related parameters in the six centres that participated in this study between January 2009 and July 2009. Examinations chosen for inclusion in this study were the most commonly performed fluoroscopic imaging-guided procedures in a pain management unit: epidural (cervical/lumbar), facet joint nerve blocks (cervical/lumbar) and trans-foraminal (cervical/lumbar). The sample size, the dose-area product (DAP) range for whole population, the mean and the third quartile DAP corrected for patient size (DAP corr ), the screening time range, the mean and the third quartile screening time are presented. The proposed DRLs for epidural, facet joint nerve blocks and trans-foraminal are 0.5, 2.5 and 3 Gy cm 2 for DAP values and 12, 60 and 50 s for screening times, respectively. In the absence of national diagnostic reference levels (DRLs) for pain management fluoroscopic procedures, these DAP and screening time values provide a possible way of establishing provisional DRLs for local use. The values for each examination type could be used as a baseline against which to monitor the effectiveness of dose reduction strategies as part of the optimisation process that is the goal of any quality control and patient dose monitoring system. (authors)

Low-level lasers alter mRNA levels from traditional reference genes used in breast cancer cells

Science.gov (United States)

Teixeira, A. F.; Canuto, K. S.; Rodrigues, J. A.; Fonseca, A. S.; Mencalha, A. L.

2017-07-01

Cancer is among the leading causes of mortality worldwide, increasing the importance of treatment development. Low-level lasers are used in several diseases, but some concerns remains on cancers. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is a technique used to understand cellular behavior through quantification of mRNA levels. Output data from target genes are commonly relative to a reference that cannot vary according to treatment. This study evaluated reference genes levels from MDA-MB-231 cells exposed to red or infrared lasers at different fluences. Cultures were exposed to red and infrared lasers, incubated (4 h, 37 °C), total RNA was extracted and cDNA synthesis was performed to evaluate mRNA levels from ACTB, GUSB and TRFC genes by RT-qPCR. Specific amplification was verified by melting curves and agarose gel electrophoresis. RefFinder enabled data analysis by geNorm, NormFinder and BestKeeper. Specific amplifications were obtained and, although mRNA levels from ACTB, GUSB or TRFC genes presented no significant variation through traditional statistical analysis, Excel-based tools revealed that the use of these reference genes are dependent of laser characteristics. Our data showed that exposure to low-level red and infrared lasers at different fluences alter the mRNA levels from ACTB, GUSB and TRFC in MDA-MB-231 cells.

1997 N-Basin Administrative Control Level Dose Extension

International Nuclear Information System (INIS)

Nellesen, A.L.

1997-04-01

This document provides justification for extending the Administrative Control Level of 500 mrem per year to 1,000 mrem per year Total Effective Dose Equivalent for workers involved with N-Reactor Basin Deactivation in accordance with established procedures

Doses from radiation exposure

International Nuclear Information System (INIS)

Menzel, H-G.; Harrison, J.D.

2012-01-01

Practical implementation of the International Commission on Radiological Protection’s (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP’s 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effective dose. In preparation for the calculation of new dose coefficients, Committee 2 and its task groups have provided updated nuclear decay data (ICRP Publication 107) and adult reference computational phantoms (ICRP Publication 110). New dose coefficients for external exposures of workers are complete (ICRP Publication 116), and work is in progress on a series of reports on internal dose coefficients to workers from inhaled and ingested radionuclides. Reference phantoms for children will also be provided and used in the calculation of dose coefficients for public exposures. Committee 2 also has task groups on exposures to radiation in space and on the use of effective dose.

Hydroxychloroquine Blood Levels in Systemic Lupus Erythematosus: Clarifying Dosing Controversies and Improving Adherence.

Science.gov (United States)

Durcan, Laura; Clarke, William A; Magder, Laurence S; Petri, Michelle

2015-11-01

Hydroxychloroquine (HCQ) is used for its effect on systemic lupus erythematosus (SLE) disease activity and longterm benefits. This can be limited by adherence. One way to assess adherence is to measure blood levels. Conflicting data exist regarding blood levels and disease activity. There is disagreement about dosing; rheumatologists recommend weight-based dosing while some other specialists advocate height-based "ideal body weight" dosing. Patients were prescribed HCQ not exceeding 6.5 mg/kg (max 400 mg/day). In hemodialysis, the dose was 200 mg after each session, and in renal insufficiency it was 200 mg/day. Levels were measured at each visit with a therapeutic range of 500-2000 ng/ml. Patients were divided according to baseline blood level. To assess the effect of measurement and counseling on adherence, we compared the proportion of patients with a level of 500 ng/ml or higher based on the number of prior assessments. The proportion of patients with HCQ levels in the therapeutic range differed significantly by age, sex, and Vitamin D level. There was a trend toward lower levels with renal failure. Blood levels were similar regardless of height and ideal body weight. Comparing those with undetectable, subtherapeutic, and therapeutic levels, disease activity decreased (SLE Disease Activity Index 2.92, 2.36, and 2.20, p = 0.04 for trend). At first, 56% were therapeutic, and by the third measurement this increased to 80% (p ≤ 0.0001). There was a trend toward higher disease activity with lower HCQ levels. Renal failure dosing led to suboptimum levels. We show that weight-based dosing (max 400 mg daily) is appropriate and that height does not appear to influence levels. Measurement, counseling, and repeated testing can increase adherence rates.

Background levels and radiation dose yield of o-tyrosine in chicken meat

International Nuclear Information System (INIS)

Chuaqui-Offermanns, N.; McDougall, T.

1991-01-01

The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 +/- 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 +/- 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5 degrees C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 + 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 + 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8 degrees C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing

How accurately can the peak skin dose in fluoroscopy be determined using indirect dose metrics?

International Nuclear Information System (INIS)

Jones, A. Kyle; Ensor, Joe E.; Pasciak, Alexander S.

2014-01-01

beam computed tomography or acquisition runs acquired at large primary gantry angles. When calculated uncertainty limits [−12.8%, 10%] were applied to directly measured PSD, most indirect PSD estimates remained within ±50% of the measured PSD. Conclusions: Using indirect dose metrics, PSD can be determined within ±35% for embolization procedures. Reference air kerma can be used without modification to set notification limits and substantial radiation dose levels, provided the displayed reference air kerma is accurate. These results can reasonably be extended to similar procedures, including vascular and interventional oncology. Considering these results, film dosimetry is likely an unnecessary effort for these types of procedures when indirect dose metrics are available

Assessment of dose level of ionizing radiation in army scrap

International Nuclear Information System (INIS)

Abdel Hamid, S. M.

2010-12-01

Radiation protection is the science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy radiation. Ionizing radiation is widely used in industry and medicine. Any human activity of nuclear technologies should be linked to the foundation of scientific methodology and baseline radiation culture to avoid risk of radiation and should be working with radioactive materials and expertise to understand, control practices in order to avoid risks that could cause harm to human and environment. The study was conducted in warehouses and building of Sudan air force Khartoum basic air force during September 2010. The goal of this study to estimate the radiation dose and measurement of radioactive contamination of aircraft scrap equipment and increase the culture of radiological safety as well as the concept of radiation protection. The results showed that there is no pollution observed in the contents of the aircraft and the spire part stores outside, levels of radiation dose for the all contents of the aircraft and spire part within the excitable level, except temperature sensors estimated radiation dose about 43 μSv/h outside of the shielding and 12 μSv/h inside the shielding that exceeded the internationally recommended dose level. One of the most important of the identification of eighteen (18) radiation sources used in temperature and fuel level sensors. These are separated from the scrap, collected and stored in safe place. (Author)

Lethal doses of ionizing radiation versus endogenous level of superoxide dismutase

Energy Technology Data Exchange (ETDEWEB)

Lipecka, K; Domanski, T; Dniaszewska, K; Grabowska, B; Pietrowicz, D; Lindner, P; Cisowska, B; Gorski, H [Military Medical Academy, Lodz (Poland). Inst. of Occupational Medicine

1982-06-22

The stability of superoxide dismutase (SOD) as well as its activity distribution in a human population were investigated. The SOD activity level of the erythrocytes proved to be an index for the endogenous SOD activity in the whole body. In a rat population, having similar SOD frequency distribution as a human population, the mortality due to acute irradiation depended on the SOD level; after a single acute dose approximating the lethal dose (LD/sub 50/30/) the survival depended distinctly on the endogenous SOD activity level.

Dose levels from thoracic and pelvic examinations in two pediatric radiological departments in Norway - a comparison study of dose-area product and radiographic technique

International Nuclear Information System (INIS)

Kjernlie Saether, Hilde; Traegde Martinsen, Anne Catrine; Lagesen, Bente; Platou Holsen, Eva; Oevreboe, Kirsti Marie

2010-01-01

Background: Pediatric doses expressed in dose-area product (DAP) can be retrieved from only a few publications; most of which correlate DAP to patient size or large age spans. In clinical practice age is often the only available parameter describing the patient, and thus, evaluation of dose levels in pediatric radiology on the basis of DAP related to age alone would be useful in optimization work. Purpose: To provide comparable data on age-related DAP from thoracic and pelvic radiological examinations of children, and evaluate the usefulness of comparing age-related DAP and radiographic technique between systems to identify areas with potential for optimization. Material and Methods: DAP, age, and radiographic technique were registered for 575 thoracic examinations and 371 pelvic examinations of children from newborn up to 14 years of age in groups with an age span of 1 year, performed with two digital flat-panel systems and one computed radiography system. Results: DAP varies from 2.2 to 54.0 mGycm2 for thoracic examinations, and from 4.6 to 532.5 mGycm2 for pelvic examinations. There are significant differences in DAP between systems and departments due to differences in technique, equipment, and staff. Conclusion: This study provides comparable data on age-related DAP from thoracic and pelvic radiological examinations of children, which could be used as an input to estimate diagnostic reference levels. The comparison between systems of DAP and radiographic technique has proven useful in identifying areas where there may be a potential for optimization.

Radiation dose monitoring in the clinical routine

Energy Technology Data Exchange (ETDEWEB)

Guberina, Nika [UK Essen (Germany). Radiology

2017-04-15

Here we describe the first clinical experiences regarding the use of an automated radiation dose management software to monitor the radiation dose of patients during routine examinations. Many software solutions for monitoring radiation dose have emerged in the last decade. The continuous progress in radiological techniques, new scan features, scanner generations and protocols are the primary challenge for radiation dose monitoring software systems. To simulate valid dose calculations, radiation dose monitoring systems have to follow current trends and stay constantly up-to-date. The dose management software is connected to all devices at our institute and conducts automatic data acquisition and radiation dose calculation. The system incorporates 18 virtual phantoms based on the Cristy phantom family, estimating doses in newborns to adults. Dose calculation relies on a Monte Carlo simulation engine. Our first practical experiences demonstrate that the software is capable of dose estimation in the clinical routine. Its implementation and use have some limitations that can be overcome. The software is promising and allows assessment of radiation doses, like organ and effective doses according to ICRP 60 and ICRP 103, patient radiation dose history and cumulative radiation doses. Furthermore, we are able to determine local diagnostic reference doses. The radiation dose monitoring software systems can facilitate networking between hospitals and radiological departments, thus refining radiation doses and implementing reference doses at substantially lower levels.

Use of national metrological references of dose absorbed in water and application of the IAEA TRS nr 398 dosimetry protocol to high energy photon beams. BNM-LNHB-LCIE-SFPM working group

International Nuclear Information System (INIS)

Chauvenet, B.; Delaunay, F.; Dolo, J.M.; Le Roy, G.; Bridier, A.; Francois, P.; Sabattier, R.

2003-01-01

Metrological references of dose absorbed in water for high energy photon beams used in radiotherapy have been elaborated during the past years by national calibration laboratories, and these new references are the basis of recent dosimetry protocols. However, the passage from metrological references of air kerma to dose absorbed in water, as well as the practical application of new calibration opportunities for dosemeters in high energy X ray beams requires a specific attention to maintain the consistency of dose measurement references over the hospital site. In this respect, this guide aims at the application of these metrological references. It proposes recommendations for the application of metrological references in terms of dose absorbed in water on the hospital site with reference to their determination conditions and to the implementation of the new IAEA dosimetry protocol (TRS nr 398). Thus, this guide proposes an overview of metrological references in French calibration laboratories, presents calibration methods (air kerma in a cobalt 60 gamma photon beam, dose absorbed in water) and a comparison with the IAEA TRS 277 dosimetry protocol. It addresses various practical aspects, and discusses uncertainties

Patient dose, gray level and exposure index with a computed radiography system

Science.gov (United States)

Silva, T. R.; Yoshimura, E. M.

2014-02-01

Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

Patient dose surveys for radiological examinations in Dutch hospitals between 1993 and 2000

International Nuclear Information System (INIS)

Spoelstra, F.M.; Geleijns, J.; Broerse, J.J.; Teeuwisse, W.M.; Zweers, D.

2001-01-01

Our inventory studies on radiation dose to patients in Dutch hospitals are reviewed and compared with current European guidelines on patient dose and reference dose values of the NRPB. Between the years 1993 and 2000 doses were measured and effective dose was assessed at 14 hospitals for paediatric radiography, at 18 hospitals for PA chest radiography, at 10 respectively 9 hospitals for barium meal and barium enema examinations and at 18 hospitals for CT scans of the brain, chest (including high resolution CT of the chest), abdomen and lumbar spine in The Netherlands. Effective doses varied from 1 μSv (AP chest radiograph premature) to 26 mSv (CT abdomen scan). Doses were in general well below the reference dose values, with the exception of CT where the dose length product often exceeded reference levels. Interhospital variations were considerable, the largest range was observed for PA chest examinations, i.e.a ratio of 27 between maximum and minimum effective dose. (author)

Developing regional weight-for-age growth references for malaria-endemic countries to optimize age-based dosing of antimalarials

NARCIS (Netherlands)

Hayes, Daniel J.; van Buuren, Stef; ter Kuile, Feiko O.; Stasinopoulos, D. Mikis; Rigby, Robert A.; Terlouw, Dianne J.

2015-01-01

To derive regional weight-for-age growth references to help optimize age-based dosing of antimalarials in Africa, the Americas, South-East Asia and the Western Pacific. A weight-for-age database was constructed from pre-existing population-based anthropometric data obtained from household surveys

Nordic working group for medical x-ray diagnostics: Diagnostic reference levels within xray diagnostics - experiences in the Nordic countries

International Nuclear Information System (INIS)

Leitz, W.; Groen, P.; Servomaa, A.; Einarsson, G.; Olerud, H.

2003-01-01

Medical x-ray diagnostics is one of the few applications of ionising radiation where people are irradiated on purpose. The strategy for radiation protection is also different compared to that in other areas that have the zero-alternative as its ultimate goal, meaning that no human beings at all are exposed in these practices. The focus in x-ray diagnostics concerning radiation protection is justification and optimisation. Optimisation implies that the examination is performed in such a way that the radiation dose is as small as possible without jeopardising the diagnostic security. X- ray diagnostics is a complex method where many technical parameters and methodology factors together are interacting in the determination of radiation dose and image quality. The optimisation process is not a simple and uncomplicated procedure, this difficulty is reflected in many international and national surveys showing a large spread of patient doses for one and the same type of examination. The concept diagnostic reference levels (DRL) has been introduced as a tool for reducing this wide distribution that is obviously indicating a lack of optimisation, and for cutting the highest radiation doses. In this presentation the concept for DRL and the experience gained in the Nordic countries with DRL are described. (orig.)

ESTIMATION OF EXPOSURE DOSES FOR THE SAFE MANAGEMENT OF NORM WASTE DISPOSAL.

Science.gov (United States)

Jeong, Jongtae; Ko, Nak Yul; Cho, Dong-Keun; Baik, Min Hoon; Yoon, Ki-Hoon

2018-03-16

Naturally occurring radioactive materials (NORM) wastes with different radiological characteristics are generated in several industries. The appropriate options for NORM waste management including disposal options should be discussed and established based on the act and regulation guidelines. Several studies calculated the exposure dose and mass of NORM waste to be disposed in landfill site by considering the activity concentration level and exposure dose. In 2012, the Korean government promulgated an act on the safety control of NORM around living environments to protect human health and the environment. For the successful implementation of this act, we suggest a reference design for a landfill for the disposal of NORM waste. Based on this reference landfill, we estimate the maximum exposure doses and the relative impact of each pathway to exposure dose for three scenarios: a reference scenario, an ingestion pathway exclusion scenario, and a low leach rate scenario. Also, we estimate the possible quantity of NORM waste disposal into a landfill as a function of the activity concentration level of U series, Th series and 40K and two kinds of exposure dose levels, 1 and 0.3 mSv/y. The results of this study can be used to support the establishment of technical bases of the management strategy for the safe disposal of NORM waste.

Analysis of data related to the update of diagnosis reference levels in radiology and nuclear medicine. Assessment 2009-2010

International Nuclear Information System (INIS)

Roch, Patrice; Celier, David

2012-10-01

This report presents and comments the results of the analysis of 'patient' dosimetric data which radiology and nuclear medicine establishments had to transmit to the IRSN. The first part concerns conventional radiology and the analysis is made from a general point of view, and then by examination type (in the case of adults and of children). A synthesis of results since 2004 is proposed in terms of transmitted data, of data representativeness, of influence of detection technology on the delivered dose, of evolution of diagnosis reference level. With the same approach, the next parts address scanography examinations and nuclear medicine

Evaluation of multiple scan average dose (MSAD) levels in computerized tomography in Minas Gerais state, Brazil; Avaliacao dos niveis de dose media em cortes multiplos (MSAD) em tomografia computadorizada no estado de Minas Gerais

Energy Technology Data Exchange (ETDEWEB)

Alonso, Thessa C., E-mail: alonso@cdtn.br [Centro de Desenvolvimento de Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Vieira, Leandro de A.; Barbosa, Nayra V.; Oliveira, Jeyselaine R. de; Cesar, Adriana C.Z. [Secretaria de Vigilancia Sanitaria de Minas Gerais, Belo Horizonte, MG (Brazil); Silva, Teogenes A. da [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear. Programa de Ciencias e Tecnicas Nucleares

2014-07-01

Computed Tomography (CT) grows every year and is a diagnostic method that has revolutionized radiology with advances in procedures for obtaining image. However, the indiscriminate use of this method generates relatively high doses in patients. The diagnostic reference levels (DRLs) is a practical tool to promote the evaluation of existing protocols. The optimization and the periodic review of the protocols are important to balance the risk of radiation. The present study aims to conduct a survey of levels of MSAD of Minas Gerais following the procedures recommended by current Brazilian law. (author)

Comparing climate and cost impacts of reference levels for reducing emissions from deforestation

Energy Technology Data Exchange (ETDEWEB)

Busch, Jonah [Center for Applied Biodiversity Science, Conservation International, 2011 Crystal Drive, Suite 500, Arlington, VA (United States); Strassburg, Bernardo [Center for Social and Economic Research on the Global Environment, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Cattaneo, Andrea [Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540-1644 (United States); Lubowski, Ruben [Environmental Defense Fund, 1875 Connecticut Avenue NW, Washington, DC (United States); Bruner, Aaron; Rice, Richard; Boltz, Frederick [Conservation International, 2011 Crystal Drive, Suite 500, Arlington, VA (United States); Creed, Anna; Ashton, Ralph, E-mail: jbusch@conservation.or [Terrestrial Carbon Group, 900 17th Street NW, Suite 700, Washington, DC (United States)

2009-10-15

The climate benefit and economic cost of an international mechanism for reducing emissions from deforestation and degradation (REDD) will depend on the design of reference levels for crediting emission reductions. We compare the impacts of six proposed reference level designs on emission reduction levels and on cost per emission reduction using a stylized partial equilibrium model (the open source impacts of REDD incentives spreadsheet; OSIRIS). The model explicitly incorporates national incentives to participate in an international REDD mechanism as well as international leakage of deforestation emissions. Our results show that a REDD mechanism can provide cost-efficient climate change mitigation benefits under a broad range of reference level designs. We find that the most effective reference level designs balance incentives to reduce historically high deforestation emissions with incentives to maintain historically low deforestation emissions. Estimates of emission reductions under REDD depend critically on the degree to which demand for tropical frontier agriculture generates leakage. This underscores the potential importance to REDD of complementary strategies to supply agricultural needs outside of the forest frontier.

Comparing climate and cost impacts of reference levels for reducing emissions from deforestation

International Nuclear Information System (INIS)

Busch, Jonah; Strassburg, Bernardo; Cattaneo, Andrea; Lubowski, Ruben; Bruner, Aaron; Rice, Richard; Boltz, Frederick; Creed, Anna; Ashton, Ralph

2009-01-01

The climate benefit and economic cost of an international mechanism for reducing emissions from deforestation and degradation (REDD) will depend on the design of reference levels for crediting emission reductions. We compare the impacts of six proposed reference level designs on emission reduction levels and on cost per emission reduction using a stylized partial equilibrium model (the open source impacts of REDD incentives spreadsheet; OSIRIS). The model explicitly incorporates national incentives to participate in an international REDD mechanism as well as international leakage of deforestation emissions. Our results show that a REDD mechanism can provide cost-efficient climate change mitigation benefits under a broad range of reference level designs. We find that the most effective reference level designs balance incentives to reduce historically high deforestation emissions with incentives to maintain historically low deforestation emissions. Estimates of emission reductions under REDD depend critically on the degree to which demand for tropical frontier agriculture generates leakage. This underscores the potential importance to REDD of complementary strategies to supply agricultural needs outside of the forest frontier.

Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source

International Nuclear Information System (INIS)

Li, Gang; Xu, Jiayun; Zhang, Jie

2015-01-01

Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3 He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3 He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter. - Highlights: • The scope of the affected area for

Deposition of 90Sr in bone and the relevant dose

International Nuclear Information System (INIS)

Kawamura, Hisao

1976-01-01

The deposition of fallout 90 Sr in bone and radiation dose from the nuclide in Japan is reviewed with special reference to (i) the intraskeletal distribution of 90 Sr and reference bone, (ii) bone models for predicting 90 Sr level and (iii) possible problems in applying dose rate factors to Japanese, especially to infants and adolescents. An evidence is presented for the assumption that the ratio of the 90 Sr concentration in a particular bone to that in vertebra will reach the ratio observed for stable strontium under the virtually constant intake of 90 Sr. The importance of surveying 90 Sr levels in different bones is stressed. Observed Ratios (bone/diet) found for Japanese are noticeably lower than those reported for Europeans and Americans. The recently presented model for the retention of alkaline earth elements in man by ICRP will be useful if only adults are concerned. Dose rate factors for 90 Sr in bone should be given as a function of age for the purpose of better estimation of dose commitments. The cumulative absorbed doses to bone tissues calculated with the Palmley-Mays model and with the Spiers model show remarkably higher levels in school children and young adults than the mean level. (auth.)

Intraocular levels of methotrexate after oral low-dose treatment in chronic uveitis.

Science.gov (United States)

Puchta, Joachim; Hattenbach, Lars-Olof; Baatz, Holger

2005-01-01

To determine the intraocular levels of methotrexate in low-dose treatment of noninfectious uveitis. One day after oral administration, the methotrexate level was measured in the aqueous humor and serum of a patient with noninfectious uveitis, who underwent cataract surgery. A fluorescence polarization immunoassay was used for determination. After oral administration, methotrexate was only measurable in aqueous humor but not in serum. In uveitis, orally administered low-dose methotrexate reaches detectable levels in aqueous humor, even in the absence of detectable levels in serum. Copyright (c) 2005 S. Karger AG, Basel.

SU-G-BRB-14: Uncertainty of Radiochromic Film Based Relative Dose Measurements

Energy Technology Data Exchange (ETDEWEB)

Devic, S; Tomic, N; DeBlois, F; Seuntjens, J [McGill University, Montreal, QC (Canada); Lewis, D [RCF Consulting, LLC, Monroe, CT (United States); Aldelaijan, S [King Faisal Specialist Hospital & Research Center, Riyadh (Saudi Arabia)

2016-06-15

Purpose: Due to inherently non-linear dose response, measurement of relative dose distribution with radiochromic film requires measurement of absolute dose using a calibration curve following previously established reference dosimetry protocol. On the other hand, a functional form that converts the inherently non-linear dose response curve of the radiochromic film dosimetry system into linear one has been proposed recently [Devic et al, Med. Phys. 39 4850–4857 (2012)]. However, there is a question what would be the uncertainty of such measured relative dose. Methods: If the relative dose distribution is determined going through the reference dosimetry system (conversion of the response by using calibration curve into absolute dose) the total uncertainty of such determined relative dose will be calculated by summing in quadrature total uncertainties of doses measured at a given and at the reference point. On the other hand, if the relative dose is determined using linearization method, the new response variable is calculated as ζ=a(netOD)n/ln(netOD). In this case, the total uncertainty in relative dose will be calculated by summing in quadrature uncertainties for a new response function (σζ) for a given and the reference point. Results: Except at very low doses, where the measurement uncertainty dominates, the total relative dose uncertainty is less than 1% for the linear response method as compared to almost 2% uncertainty level for the reference dosimetry method. The result is not surprising having in mind that the total uncertainty of the reference dose method is dominated by the fitting uncertainty, which is mitigated in the case of linearization method. Conclusion: Linearization of the radiochromic film dose response provides a convenient and a more precise method for relative dose measurements as it does not require reference dosimetry and creation of calibration curve. However, the linearity of the newly introduced function must be verified. Dave Lewis

Radon reference levels and priority areas considering optimisation and avertable lung cancers

International Nuclear Information System (INIS)

Bochicchio, F.; Venoso, G.; Antignani, S.; Carpentieri, C.

2017-01-01

Protection from radon exposure in workplaces and dwellings, as included in the latest relevant international regulations and recommendations, is based on the new concept of 'reference level' whose meaning is significantly different from that of previous 'action level' concept. In fact, whereas remedial actions had to be considered only for radon concentrations above the action level, actions to optimise radon exposure are requested with priority above reference level but optimisation should be applied also for radon concentrations below reference level. Similar considerations can be applied to the usually called 'Rn-prone' areas, which are here proposed to be regulated as 'priority' areas. The main implication of these new challenging concepts is a substantial increase of avertable lung cancer deaths, as it will be shown using Italian data. Some practical examples of possible policy actions fitting an approach based on these new concepts will also be given, which could be useful for the implementation of the Council Directive 2013/59/Euratom. (authors)

Recent results on the linearity of the dose-response relationship for radiation-induced mutations in human cells by low dose levels

International Nuclear Information System (INIS)

Traut, H.

1987-01-01

Five studies made by various authors in the last years are discussed, which are significant in that the response of human cells to low-dose irradiation is determined directly and not by extrapolation, and which also provide information on the mutagenic effects of low radiation doses. The results of these studies do not indicate any other than a linear response for induction of mutations by low-dose irradiation, nor are there any reasons observable for assuming the existence of a threshold dose. It is very likely therefore that cancer initiation at the low dose level also is characterized by a linear relationship. Although threshold dose levels cannot generally be excluded, and maybe are only too low to be detected by experiment, there is no plausible biophysical argument for assuming the existence of such microdose threshold. (orig./MG) [de

Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites

Energy Technology Data Exchange (ETDEWEB)

Widmann, Gerlig; Schullian, Peter [Medical University of Innsbruck, Department of Radiology, Innsbruck (Austria); Al-Shawaf, Reema; Al-Sadhan, Ra' ed; Al-Ekrish, Asma' a A. [King Saud University, Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, Riyadh (Saudi Arabia); Hoermann, Romed [Medical University of Innsbruck, Division of Clinical and Functional Anatomy, Innsbruck (Austria)

2017-05-15

Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR. Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures. Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel). Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used. (orig.)

Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites

International Nuclear Information System (INIS)

Widmann, Gerlig; Schullian, Peter; Al-Shawaf, Reema; Al-Sadhan, Ra'ed; Al-Ekrish, Asma'a A.; Hoermann, Romed

2017-01-01

Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR. Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures. Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel). Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used. (orig.)

Is patient size important in dose determination and optimization in cardiology?

International Nuclear Information System (INIS)

Reay, J; Chapple, C L; Kotre, C J

2003-01-01

Patient dose determination and optimization have become more topical in recent years with the implementation of the Medical Exposures Directive into national legislation, the Ionising Radiation (Medical Exposure) Regulations. This legislation incorporates a requirement for new equipment to provide a means of displaying a measure of patient exposure and introduces the concept of diagnostic reference levels. It is normally assumed that patient dose is governed largely by patient size; however, in cardiology, where procedures are often very complex, the significance of patient size is less well understood. This study considers over 9000 cardiology procedures, undertaken throughout the north of England, and investigates the relationship between patient size and dose. It uses simple linear regression to calculate both correlation coefficients and significance levels for data sorted by both room and individual clinician for the four most common examinations, left ventrical and/or coronary angiography, single vessel stent insertion and single vessel angioplasty. This paper concludes that the correlation between patient size and dose is weak for the procedures considered. It also illustrates the use of an existing method for removing the effect of patient size from dose survey data. This allows typical doses and, therefore, reference levels to be defined for the purposes of dose optimization

An Assessment of Cs-137, R-226 and Pa-239, 240 doses for aquatic and terrestrial reference organisms in Poland

International Nuclear Information System (INIS)

Krajewski, P.; Suplinska, M.; Rosiak, I.

2004-01-01

The doses assessment for aquatic and terrestrial reference organisms was performed, based on the methodology elaborated by U.S. Department of Energy. Four organism types and their corresponding dose limits were used, and the principal exposure pathways were considered for aquatic animal, riparian animal, terrestrial plant, and terrestrial animal organism types respectively. Terrestrial rodent (apodemus flavicollis), Baltic Sea fish (cod, sprat, herring, plaice) and crustaceans (Sanduria entomon and Mytilus edulis) were taken in to special consideration. In the first screening approach the annual doses from 137Cs and 239Pu (bomb-tests-fallout and Czarnobyl origin) and 226Ra (natural radionuclide) to biota were calculated at average, minimum and maximum concentrations of these radionuclides observed in soil, water, and sediment using the default bioaccumulation factors as well as lumped parameters values recommended by DOE Standard. The concentrations of 137Cs measured in the most contaminated region in Poland (Stare Olesno 380 Bqxkg-1 d.w.) and the concentrations of 226Ra for Southern regions of Poland with elevated levels of 226Ra in soil (100 B kg-1 d.w.) were taken in the dose assessment for terrestrial animals. The concentrations of 137Cs and 239Pu and 226Ra determined in see water and bottom sediments from two sub-areas (Gdansk Basin and Bornholm Basin) were used in the dose assessment for aquatic biota. In the second ''site specific'' approach the average empirically measured concentrations of radionuclides in animal tissues were used. At the first approach the total maximal annual doses for terrestrial plants were less then one percent of the recommended dose limits ( 3600 mGyxy-1 ) and items for seawater organisms did not exceed a 40% of this limit whereas the total maximal annual doses for terrestrial animal were close to the recommended dose limit (360 mGyxy-1). It prompted to start supplementary site-specific biota dose assessment through site

Natural external radiation level and population dose in Hunan province

International Nuclear Information System (INIS)

1985-01-01

A survey of the natural external radiation level in Hunan Province is reported. The measurements were performed with FD-71 scintillation radiometers. On the basis of measurements at about 1,600 locations, the contribution from cosmic radiation is found to be 3.0 x 10 -8 Gy.h -1 , and the average absorbed dose rates in air from terrestrial γ-radiation for outdoors, indoors and roads are determined to be 9.2, 13.1 and 9.0 x 10 -8 Gy.h -1 , respectively. The γ-radiation indoors is markedly higher than that outdoors by a factor of 1.42. The lowest γ-radiation level is found in the sedimentary plain around Donting Lake, while the highest absorbed dose rates in air from terrestrial radiation are observed in some areas with exposed granites. The indoor γ-radiation in brick houses is markedly higher than that in wooden houses. Tarred roads have evidently lower radiation level than sand-gravel roads or concrete roads. The annual effective dose equivalents to the population from cosmic and terrestrial sources are 0.256 and 0.756 mSv, respectively, with a total value of 1.012 mSv

Dose assessment in pediatric computerized tomography

International Nuclear Information System (INIS)

Vilarinho, Luisa Maria Auredine Lima

2004-01-01

The objective of this work was the evaluation of radiation doses in paediatric computed tomography scans, considering the high doses usually involved and the absence of any previous evaluation in Brazil. Dose values were determined for skull and abdomen examinations, for different age ranges, by using the radiographic techniques routinely used in the clinical centers investigated. Measurements were done using pencil shape ionization chambers inserted in polymethylmethacrylate (PMMA) phantoms. These were compact phantoms of different diameters were specially designed and constructed for this work, which simulate different age ranges. Comparison of results with published values showed that doses were lower than the diagnostic reference levels established to adults exams by the European Commission. Nevertheless, doses in paediatric phantoms were higher than those obtained in adult phantoms. The paediatric dose values obtained in Hospitals A and B were lower than the reference level (DRL) adopted by SHIMPTON for different age ranges. In the range 0 - 0.5 year (neonatal), the values of DLP in Hospital B were 94 por cent superior to the DRL For the 10 years old children the values of CTDI w obtained were inferior in 89 por cent for skull and 83 por cent for abdomen examinations, compared to the values published by SHRIMPTON and WALL. Our measured CTDI w values were inferior to the values presented for SHRIMPTON and HUDA, for all the age ranges and types of examinations. It was observed that the normalized dose descriptors values in children in the neonatal range were always superior to the values of doses for the adult patient. In abdomen examinations, the difference was approximately 90% for the effective dose (E) and of 57%.for CTDI w . (author)

Patient doses in chest CT examinations: Comparison of various CT scanners

Directory of Open Access Journals (Sweden)

Božović Predrag

2013-01-01

Full Text Available This paper presents results from study on patient exposure level in chest CT examinations. CT scanners used in this study were various Siemens and General Electric (GE models. Data on patient doses were collected for adult and pediatric patients. Doses measured for adult patients were lower then those determined as Diagnostic Reference Levels (DRL for Europe, while doses for pediatric patients were similar to those found in published data. As for the manufactures, slightly higher doses were measured on GE devices, both for adult and pediatric patients.

Level of terrestrial gamma radiation and doses to population in Jiangsu province

International Nuclear Information System (INIS)

1985-01-01

In this paper the results of investigation of terrestrial gamma radiation level in Jiangsu Province are reported and the population doses due to this radiation are estimated. The sketch map of the geographical distribution of the terrestrial gamma radiation level is given. In this investigation FD-71 portable scintillation counters and RSS-111 high pressure ionization chambers were used. The results showed that the terrestrial gamma absorbed dose rates in air for indoors and outdoors were 10.7 x 10 -8 Gy/h and 6.5 x 10 -8 Gy/h (weighted values) respectively. The indoors-to-outdoors ratio was 1.65. The total (indoor plus outdoor) annual effective dose equivalent from terrestrial gamma radiation, averaged over the population in this province, was 6.0 x 10 -4 Sv. The collective annual effective dose equivalent was 3.6 x 10 4 man.Sv. Therefore, the absorbed dose to population in Jiangsu Province is in the range of the normal background

Supplementary comparison CCRI(I)-S2 of standards for absorbed dose to water in 60Co gamma radiation at radiation processing dose levels

DEFF Research Database (Denmark)

Burns, D. T.; Allisy-Roberts, P. J.; Desrosiers, M. F.

2011-01-01

Eight national standards for absorbed dose to water in 60Co gamma radiation at the dose levels used in radiation processing have been compared over the range from 1 kGy to 30 kGy using the alanine dosimeters of the NIST and the NPL as the transfer dosimeters. The comparison was organized...... by the Bureau International des Poids et Mesures, who also participated at the lowest dose level using their radiotherapy-level standard for the same quantity. The national standards are in general agreement within the standard uncertainties, which are in the range from 1 to 2 parts in 102. Evidence of a dose...

Dose levels in the hot cells area ININ

International Nuclear Information System (INIS)

Torre, J. De la; Ramirez, J.M.; Solis, M.L.

2004-01-01

The Laboratory of Hot Cells (LCC) located in the National Institute of Nuclear Research (ININ) is an institution, it is an area where radioactive material is managed with different activity values, in function of its original design for 10,000 curies of Co-60. Managing this materials in the installation, it implies to measure and to analyze the dose levels that the POE will receive as well as the implementation of appropriate measures of radiological protection and radiological safety, so that that is completed settled down by the concept ALARA. In this work they are carried out mensurations of the levels of the dose to receive for the POE when managing radionuclides with maximum activities that can be allowed in function of the current conditions of the cells and an evaluation of the obtained results is made comparing them with the effective international norms as well as the application of the program of surveillance and radiological protection implemented for the development of the works that are carry out in the installation. (Author)

Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

International Nuclear Information System (INIS)

Abdollahi, Hamid; Shiri, Isaac; Salimi, Yazdan; Sarebani, Maghsoud; Mehdinia, Reza; Deevband, Mohammad Reza; Mahdavi, Seied Rabi; Sohrabi, Ahmad; Bitarafan-Rajabi, Ahmad

2016-01-01

Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

Radiation dose in cardiac SPECT/CT: An estimation of SSDE and effective dose

Energy Technology Data Exchange (ETDEWEB)

Abdollahi, Hamid, E-mail: Hamid_rbp@yahoo.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shiri, Isaac [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Salimi, Yazdan [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarebani, Maghsoud; Mehdinia, Reza [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Deevband, Mohammad Reza [Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mahdavi, Seied Rabi [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Radiation Biology Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sohrabi, Ahmad [Department of Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bitarafan-Rajabi, Ahmad, E-mail: bitarafan@hotmail.com [Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Nuclear Medicine, Rajaei Cardiovascular, Medical and Research Center, Iran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

2016-12-15

Aims: The dose levels for Computed Tomography (CT) localization and attenuation correction of Single Photon Emission Computed Tomography (SPECT) are limited and reported as Volume Computed Tomography Dose Index (CTDIvol) and Dose-Length Product (DLP). This work presents CT dose estimation from Cardiac SPECT/CT based on new American Association of Physicists in Medicine (AAPM) Size Specific Dose Estimation (SSDE) parameter, effective dose, organ doses and also emission dose from nuclear issue. Material and methods: Myocardial perfusion SPECT/CT for 509 patients was included in the study. SSDE, effective dose and organ dose were calculated using AAPM guideline and Impact-Dose software. Data were analyzed using R and SPSS statistical software. Spearman-Pearson correlation test and linear regression models were used for finding correlations and relationships among parameters. Results: The mean CTDIvol was 1.34 mGy ± 0.19 and the mean SSDE was 1.7 mGy ± 0.16. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The mean ± SD of effective dose from emission, CT and total dose were 11.5 ± 1.4, 0.49 ± 0.11 and 12.67 ± 1.73 (mSv) respectively. The spearman test showed that correlation between body size and organ doses is significant except thyroid and red bone marrow. CTDIvol was strongly dependent on patient size, but SSDE was not. Emission dose was strongly dependent on patient weight, but its dependency was lower to effective diameter. Conclusion: The dose parameters including CTDIvol, DLP, SSDE, effective dose values reported here are very low and below the reference level. This data suggest that appropriate CT acquisition parameters in SPECT/CT localization and attenuation correction are very beneficial for patients and lowering cancer risks.

Calculation of normalised organ and effective doses to adult reference computational phantoms from contemporary computed tomography scanners

International Nuclear Information System (INIS)

Jansen, Jan T.M.; Shrimpton, Paul C.

2010-01-01

The general-purpose Monte Carlo radiation transport code MCNPX has been used to simulate photon transport and energy deposition in anthropomorphic phantoms due to the x-ray exposure from the Philips iCT 256 and Siemens Definition CT scanners, together with the previously studied General Electric 9800. The MCNPX code was compiled with the Intel FORTRAN compiler and run on a Linux PC cluster. A patch has been successfully applied to reduce computing times by about 4%. The International Commission on Radiological Protection (ICRP) has recently published the Adult Male (AM) and Adult Female (AF) reference computational voxel phantoms as successors to the Medical Internal Radiation Dose (MIRD) stylised hermaphrodite mathematical phantoms that form the basis for the widely-used ImPACT CT dosimetry tool. Comparisons of normalised organ and effective doses calculated for a range of scanner operating conditions have demonstrated significant differences in results (in excess of 30%) between the voxel and mathematical phantoms as a result of variations in anatomy. These analyses illustrate the significant influence of choice of phantom on normalised organ doses and the need for standardisation to facilitate comparisons of dose. Further such dose simulations are needed in order to update the ImPACT CT Patient Dosimetry spreadsheet for contemporary CT practice. (author)

Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites.

Science.gov (United States)

Widmann, Gerlig; Al-Shawaf, Reema; Schullian, Peter; Al-Sadhan, Ra'ed; Hörmann, Romed; Al-Ekrish, Asma'a A

2017-05-01

Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR. Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures. Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel). Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used. • Ultra-low-dose MDCT protocols allowed more than 90 % reductions in dose. • Decreasing the dose generally increased density and noise. • Effect of IRT on density and noise varies with reconstruction kernel. • Accuracy of low-dose protocols for interpretation of bony anatomy not known. • Effect of low doses on accuracy of computer-aided design models unknown.

Estimation of radiological dose from radon, thoron and their progeny levels in the dwellings of Shivamogga district, Karnataka, India

International Nuclear Information System (INIS)

Rangaswamvi, D.R.; Sannappa, J.; Srinivasa, E.

2018-01-01

Among all natural radiation exposure to man, inhalation of radon, thoron and their progenies are the major contributor (50 %) to the dose from ionizing radiation received by the general population. Based on the results of epidemiological studies in Europe and North America, the World Health Organization (WHO) has recommended reducing the indoor radon reference level from 200 to 100 Bq.m -3 . In view of this, focus has now been given for simultaneous measurement of radon, thoron and their progeny concentration in indoor air and also to estimate radiological dose in the dwellings of the Shivamogga district. The geology of the Shivamogga district comprises different types of rock formation such as granites, schists, magnetites and gneisses, Meta basalt, laterites, quartz and chlorite schist, Graywacke etc. Present study was concentrating more in granite bed rock regions along with their surrounding regions

Adaptation of penelope Monte Carlo code system to the absorbed dose metrology: characterization of high energy photon beams and calculations of reference dosimeter correction factors

International Nuclear Information System (INIS)

Mazurier, J.

1999-01-01

This thesis has been performed in the framework of national reference setting-up for absorbed dose in water and high energy photon beam provided with the SATURNE-43 medical accelerator of the BNM-LPRI (acronym for National Bureau of Metrology and Primary standard laboratory of ionising radiation). The aim of this work has been to develop and validate different user codes, based on PENELOPE Monte Carlo code system, to determine the photon beam characteristics and calculate the correction factors of reference dosimeters such as Fricke dosimeters and graphite calorimeter. In the first step, the developed user codes have permitted the influence study of different components constituting the irradiation head. Variance reduction techniques have been used to reduce the calculation time. The phase space has been calculated for 6, 12 and 25 MV at the output surface level of the accelerator head, then used for calculating energy spectra and dose distributions in the reference water phantom. Results obtained have been compared with experimental measurements. The second step has been devoted to develop an user code allowing calculation correction factors associated with both BNM-LPRI's graphite and Fricke dosimeters thanks to a correlated sampling method starting with energy spectra obtained in the first step. Then the calculated correction factors have been compared with experimental and calculated results obtained with the Monte Carlo EGS4 code system. The good agreement, between experimental and calculated results, leads to validate simulations performed with the PENELOPE code system. (author)

Serum level modifications of female sex hormones after radiocastration with different total doses

International Nuclear Information System (INIS)

Naujokat, B.; Rohloff, R.; Willich, N.; Eiermann, W.

1988-01-01

We determined serum level of estradiol, FSH and LH over a period of six to eight weeks after ovarian irradiation for castration with different doses (2x2.5 Gy/3x2.5 Gy/4x2.5 Gy) in 15 patients with metastatic breast cancer as compared to changes after ovarectomy in five patients. The time course of the changing estradiol-, FSH and LH-serum levels sigificantly depends on the ovarian dose. After radiological castration with a dose of 4x2.5 Gy = 10 Gy in four days the estrogen levels decrease within two to three weeks, and the FSH- and LH-levels increase after three to four weeks into the postmenopausal range. Therefore, the time course is not very different from changes after ovarectomy. (orig.) [de

Dose inhomogeneities at various levels of biological organization

International Nuclear Information System (INIS)

Bond, V.P.

1988-01-01

Dose inhomogeneities in both tumor and normal tissue, inherent to the application of boron neutron capture therapy (BNCT), can be the result not only of ununiform distribution of 10 B at various levels of biological organization, but also of the distribution of the thermal neutrons and of the energy depositions from more energetic neutrons and other radiations comprising the externally-applied beams. The severity of the problems resulting from such inhomogeneities, and approaches to evaluating them, are illustrated by three examples, at the macro, micro and intermediate levels

Application of the hybrid approach to the benchmark dose of urinary cadmium as the reference level for renal effects in cadmium polluted and non-polluted areas in Japan

International Nuclear Information System (INIS)

Suwazono, Yasushi; Nogawa, Kazuhiro; Uetani, Mirei; Nakada, Satoru; Kido, Teruhiko; Nakagawa, Hideaki

2011-01-01

Objectives: The aim of this study was to evaluate the reference level of urinary cadmium (Cd) that caused renal effects. An updated hybrid approach was used to estimate the benchmark doses (BMDs) and their 95% lower confidence limits (BMDL) in subjects with a wide range of exposure to Cd. Methods: The total number of subjects was 1509 (650 men and 859 women) in non-polluted areas and 3103 (1397 men and 1706 women) in the environmentally exposed Kakehashi river basin. We measured urinary cadmium (U-Cd) as a marker of long-term exposure, and β2-microglobulin (β2-MG) as a marker of renal effects. The BMD and BMDL that corresponded to an additional risk (BMR) of 5% were calculated with background risk at zero exposure set at 5%. Results: The U-Cd BMDL for β2-MG was 3.5 μg/g creatinine in men and 3.7 μg/g creatinine in women. Conclusions: The BMDL values for a wide range of U-Cd were generally within the range of values measured in non-polluted areas in Japan. This indicated that the hybrid approach is a robust method for different ranges of cadmium exposure. The present results may contribute further to recent discussions on health risk assessment of Cd exposure.

Application of the hybrid approach to the benchmark dose of urinary cadmium as the reference level for renal effects in cadmium polluted and non-polluted areas in Japan

Energy Technology Data Exchange (ETDEWEB)

Suwazono, Yasushi, E-mail: suwa@faculty.chiba-u.jp [Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuoku, Chiba 260-8670 (Japan); Nogawa, Kazuhiro; Uetani, Mirei [Department of Occupational and Environmental Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuoku, Chiba 260-8670 (Japan); Nakada, Satoru [Safety and Health Organization, Chiba University, 1-33 Yayoicho, Inageku, Chiba 263-8522 (Japan); Kido, Teruhiko [Department of Community Health Nursing, Kanazawa University School of Health Sciences, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942 (Japan); Nakagawa, Hideaki [Department of Epidemiology and Public Health, Kanazawa Medical University, 1-1 Daigaku, Uchnada, Ishikawa 920-0293 (Japan)

2011-02-15

Objectives: The aim of this study was to evaluate the reference level of urinary cadmium (Cd) that caused renal effects. An updated hybrid approach was used to estimate the benchmark doses (BMDs) and their 95% lower confidence limits (BMDL) in subjects with a wide range of exposure to Cd. Methods: The total number of subjects was 1509 (650 men and 859 women) in non-polluted areas and 3103 (1397 men and 1706 women) in the environmentally exposed Kakehashi river basin. We measured urinary cadmium (U-Cd) as a marker of long-term exposure, and {beta}2-microglobulin ({beta}2-MG) as a marker of renal effects. The BMD and BMDL that corresponded to an additional risk (BMR) of 5% were calculated with background risk at zero exposure set at 5%. Results: The U-Cd BMDL for {beta}2-MG was 3.5 {mu}g/g creatinine in men and 3.7 {mu}g/g creatinine in women. Conclusions: The BMDL values for a wide range of U-Cd were generally within the range of values measured in non-polluted areas in Japan. This indicated that the hybrid approach is a robust method for different ranges of cadmium exposure. The present results may contribute further to recent discussions on health risk assessment of Cd exposure.

Dose response curves for effects of low-level radiation

International Nuclear Information System (INIS)

Myers, D.K.

1980-01-01

The linear dose-response model used by international committees to assess the genetic and carcinogenic hazards of low-level radiation appears to be the most reasonable interpretation of the available scientific data that are relevant to this topic. There are, of course, reasons to believe that this model may overestimate radiation hazards in certain instances, a fact acknowledged in recent reports of these committees. The linear model is now also being utilized to estimate the potential carcinogenic hazards of other agents such as asbestos and polycyclic aromatic hydrocarbons. This model implies that there is no safe dose for any of these agents and that potential health hazards will increase in direct proportion to total accumulated dose. The practical implication is the recommendation that all exposures should be kept 'as low as reasonably achievable, economic and social factors being taken into account'. (auth)

Do the UK workplace Radon Action Levels reflect the radiation dose received by the occupants?

International Nuclear Information System (INIS)

Denman, A.R.; Parkinson, S.; Barker, S.P.; Marley, F.; Phillips, P.S.

1999-01-01

In the UK, Action Levels for radon have been established at 400 Bq m -3 for the workplace and 200 Bq m -3 for the home. We have estimated the dose received by occupants of rooms with radon levels near or above the Action Level, using hourly radon readings, and a questionnaire to record occupancy. In the workplace, results for 73 staff suggest that doses are lower than expected, partly due to part-time working and partly due to the mobility of staff. The 75% quantile for the series, corrected to a 37 hour week, is 5.2 mSv at 400 Bq m -3 . Compared to the current annual limit for radiation workers, the Action Level could be increased, but the current Action Level is compatible with the recent EEC Directive requiring a lower dose limit. However, when raised radon levels in the workplace were reduced by remediation in the series we studied, the dose reduction to staff was consistently around half of the radon level reduction. Although it would be appropriate to study more locations, this suggests an Action Level for remediated workplaces of 200 Bq m -3 . Finally, in a limited series of dose assessments in domestic properties, we found that doses could considerably exceed 5 mSv at the 200 Bq m -3 Action Level, primarily because the sample included an example of high occupancy, in our case several Asian wives in purdah, whose occupancy was almost total. (author)

Importance of the Computed Tomography Dose Index (CTDI) and Dose Length Product (DLP)

International Nuclear Information System (INIS)

Rasolomboahanginjatovo, L.M.

2014-01-01

This work is under the auspice of the International Atomic Energy Agency (IAEA) projects (RAF/9/053) untitled S trengthening of the technical capacity for the protection patients and worker . The goal of this work is to highlight the importance of the Computed Tomography Dose Index (CTDI) and the Dose Length product (DLP). Measures were done at Polyclinic of Ilafy and CRDT Anosivavaka, Antananarivo, Madagascar. Doses were evaluated by use of pencil ionization chamber model 6000-10 connected with an electrometer RAD-CHECK model 06-256. Knowledge of dose indicator and Diagnostic Reference Level (DRL) allow the monitoring of scanner within the appropriate average dosimeter. It also insures the progressive determination for the most adapted dose requirements by choice of parameters available on scanner device. Measurements confirmed that doses from scanner devices of the two centers were under DRL requirements proposed by the IAEA, the European Commission (EC) and the National Radiological Protection Board (NRPB). The present results confirm that the patient delivered doses for the two centers are optimized. [fr

Reference Japanese man

International Nuclear Information System (INIS)

Tanaka, Giichiro

1985-01-01

To make real and accurate dose assessment method so far, it is necessitated to provide ''Reference Japanese Man'' based on anotomical, physiological and biochemical data of Japanese people instead of the Reference Man presented in ICRP Publications 23 and 30. This review describes present status of researched for the purpose of establishing of Reference Japanese Man. The Reference Japanese Man is defined as a male or female adult who lives in Japan with a Japanese life-style and food custom. His stature and body weight, and the other data was decided as mean values of male or female people of Japan. As for food custom, Japanese people take significantly smaller amount of meat and milk products than Western people, while larger intake amount of cereals and marine products such as fish or seaweeds. Weight of organs is a principal factor for internal dose assessment and mean values for living Japanese adult has been investigated and the value employable for dose assessment for organs and tissues are shown. To employ these values of Reference Japanese Man, it should be taken into account of age. Metabolic parameters should also be considered. Iodine metabolism in Japanese is quite different from that of Western people. The above-mentioned data are now tentatively employing in modification of table of MIRD method and others. (Takagi, S.)

Dose level of occupational exposure in China

International Nuclear Information System (INIS)

Tian, Y.; Zhang, L.; Ju, Y.

2008-01-01

This paper discusses the dose level of Chinese occupational exposures during 1986-2000. Data on occupational exposures from the main categories in nuclear fuel cycle (uranium enrichment and conversion, fuel fabrication, reactor operation, waste management and research activity, except for uranium mining and milling because of the lack of data), medical uses of radiation (diagnostic radiation, nuclear medicine and radiotherapy) and industrial uses of radiation (industrial radiography and radioisotope production) are presented and summarised in detail. These are the main components of occupational exposures in China. In general, the average annual effective doses show a steady decreasing trend over periods: from 2.16 to 1.16 mSv in medical uses of radiation during 1990-2000; from 1.92 to 1.18 mSv in industrial radiography during 1990-2000; from 8.79 to 2.05 mSv in radioisotope production during the period 1980-2000. Almost all the average annual effective doses in discussed occupations were lower than 5 mSv in recent years (except for well-logging: 6.86 mSv in 1999) and no monitored workers were found to have received the occupational exposure exceeding 50 mSv in a single year or 100 mSv in a five-year period. So the Chinese protection status of occupation exposure has been improved in recent years. However, the average annual effective doses in some occupations, such as diagnostic radiology and coal mining, were still much higher than that of the whole world. There are still needs for further improvement and careful monitoring of occupational exposure to protect every worker from excessive occupational exposure, especially for the workers who were neglected before. (authors)

Dose management for X-ray and CT. Systematic comparison of exposition values from two institutes to diagnostic reference levels and use of results for optimisation of exposition; Dosismanagement fuer konventionelles Roentgen und CT. Systematischer Vergleich der Expositionswerte zweier radiologischer Institute mit den diagnostischen Referenzwerten und Verwendung der Ergebnisse zur Optimierung der Strahlenexposition bei diagnostischen Untersuchungen

Energy Technology Data Exchange (ETDEWEB)

Schaefer, S.; Alejandre-Lafont, E.; Krombach, G.A. [University Hospital Giessen (Germany). Dept. of Radiology; Schmidt, T. [University Hospital Giessen (Germany). Dept. of Neuroradiology; Gizewski, E.R. [University Hospital Innsbruck (Austria). Dept. of Neuroradiology; Fiebich, M. [University of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection

2014-08-15

Purpose: In 2 institutions exposure values were evaluated and compared with the 2010 updated diagnostic reference levels (DRL) and possibilities for decreasing the dose assessed. Materials and Methods: Mean exposure values obtained during a 3-month period were calculated for all modalities (X-ray: imaging plate system and digital detector; dual-source 64- and 16- slice spiral CT) as well as examination types were compared to old diagnostic reference levels in addition to DRLs introduced in 2010. Then 10 examinations of all modalities and types were accompanied by a medical physicist and optimized stepwise if necessary. Results: The mean values of X-ray examinations were above DRL. All accompanied examinations were beyond DRL except lateral lumbar spine (LSP) and lateral thoracic X-ray, which were elevated due to statistical outliers from morbidly obese patients or patients with metallic implants. For a-p LSP tube voltage was increased. While image quality was maintained, dose area product (DAP) was reduced by 50% to 123 ±61 cGy.cm{sup 2} for LSP a-p and 30% for lateral LSP to 229 ± 116 cGy.cm{sup 2}. For CT examinations, dose was below DRL. Accompanied examinations of the lumbar spine performed on a 16-slice spiral CT demonstrated a result 68% above DRL with dose length product (DLP) of 840 ± 252 cGy . cm. For optimization, pitch and tube voltage were stepwise increased and DLP reduced below DRL. Conclusion: Systematic analysis of our internal exposure values on the occasion of adaptation of DRL is crucial for prompt detection of exceeded values independently from assessment by the responsible authority and initiation of proper measures for decreasing exposure dose. Hereby active dose management is attained. (orig.)

Evaluation of entrance skin dose to the skull in diagnostic radiology

International Nuclear Information System (INIS)

Mohamed, Anas Ali Elbushari

2015-12-01

Diagnostic x-ray radiology is a common diagnostic practice.Despite of its increasing hazard to human beings, imaging procedures should be achieved with less radiation dose and sufficient image quality. The aim of this study was to estimate the entrance skin dose(ESD) for patients undergoing selected diagnostic x-ray examinations in four hospitals.The study included the examinations of the skull; posterior- anterior(PA) and lateral projections. Fifty patients were enrolled in this study. ESDs were estimated from patients specific exposure parameters using established relation between output (μGy/mAs) and tube voltage(kVp). The estimated ESDs ranged from 0.0097-0.1846 mGy for skull (PA), 0.0097-0.1399 mGy for skull (LAT). These values were acceptable as compared with the international reference dose levels. This study provides additional data that can help the regulatory authority to establish reference dose levels for diagnostic radiology in Sudan.(Author)

Hearing Tests on Mobile Devices: Evaluation of the Reference Sound Level by Means of Biological Calibration.

Science.gov (United States)

Masalski, Marcin; Kipiński, Lech; Grysiński, Tomasz; Kręcicki, Tomasz

2016-05-30

Hearing tests carried out in home setting by means of mobile devices require previous calibration of the reference sound level. Mobile devices with bundled headphones create a possibility of applying the predefined level for a particular model as an alternative to calibrating each device separately. The objective of this study was to determine the reference sound level for sets composed of a mobile device and bundled headphones. Reference sound levels for Android-based mobile devices were determined using an open access mobile phone app by means of biological calibration, that is, in relation to the normal-hearing threshold. The examinations were conducted in 2 groups: an uncontrolled and a controlled one. In the uncontrolled group, the fully automated self-measurements were carried out in home conditions by 18- to 35-year-old subjects, without prior hearing problems, recruited online. Calibration was conducted as a preliminary step in preparation for further examination. In the controlled group, audiologist-assisted examinations were performed in a sound booth, on normal-hearing subjects verified through pure-tone audiometry, recruited offline from among the workers and patients of the clinic. In both the groups, the reference sound levels were determined on a subject's mobile device using the Bekesy audiometry. The reference sound levels were compared between the groups. Intramodel and intermodel analyses were carried out as well. In the uncontrolled group, 8988 calibrations were conducted on 8620 different devices representing 2040 models. In the controlled group, 158 calibrations (test and retest) were conducted on 79 devices representing 50 models. Result analysis was performed for 10 most frequently used models in both the groups. The difference in reference sound levels between uncontrolled and controlled groups was 1.50 dB (SD 4.42). The mean SD of the reference sound level determined for devices within the same model was 4.03 dB (95% CI 3

Patient doses from x-ray examinations in Sweden - follow-up of remedial actions

International Nuclear Information System (INIS)

Joensson, Helene; Leitz, W.

2002-03-01

In early 1999 the Swedish Radiation Protection Authority (SSI) requested data about patient doses etc. for a number of specified x-ray examinations. The aim was on one hand to get a basis for planned regulations on diagnostic reference levels (DRL) and on the other hand to obtain an overview of how the situation is in the country with respect to patient doses. The licensees who reported dose values exceeding (provisional) DRL were asked to perform investigations about the grounds for the high dose and to take remedial actions for reducing the dose. In this report the outcome is presented. The dose reductions were large: on average between 35 and 60 % for the various examinations. A large proportion of the measures taken were simple and cheap, such as increase of radiation quality, improved examination methodology (smaller radiation fields, use of compression, reduced number of images or fluoroscopy time) and optimising the film processing. This is indicating that the planned regulations on diagnostic reference levels have a good chance to succeed with a large reduction of the patient doses in Sweden

Natural dose level determination at Johor State with thermoluminescence dosimetry

International Nuclear Information System (INIS)

Ahmad Termizi Ramli; Yusof Jasman

1995-01-01

This paperwork presented the results of using thermoluminescence dosimetry (TLD) method in measuring background dose level, which is done at State of Johor, South Malaysia. The problems faced also discussed

Dose intercomparison studies for standardization of high-dose dosimetry in Viet Nam

International Nuclear Information System (INIS)

Mai Hoang Hoa; Duong Nguyen Dinh; Kojima, T.

1999-01-01

The Irradiation Center of the Vietnam Atomic Energy Commission (IC-VAEC) is planning to establish a traceability system for high-dose dosimetry and to provide high-dose standards as a secondary standard dosimetry laboratory (SSDL) level in Vietnam. For countries which do not have a standard dosimetry laboratory, the participation in the International Dose Assurance Service (IDAS) operated by the International Atomic Energy Agency (IAEA) is the most common means to verify own dosimetry performance with a certain uncertainty. This is, however, only one-direction dose intercomparison with evaluation by IAEA including unknown parameter at participant laboratories. The SSDL level laboratory should have traceability as well as compatibility, ability to evaluate uncertainties of its own dosimetry performance by itself In the present paper, we reviewed our dosimetry performance through two-way dose intercomparison studies and self-evaluation of uncertainty in our dosimetry procedure. The performance of silver dichromate dosimeter as reference transfer dosimeter in IC-VAEC was studied through two-way blind dose intercomparison experiments between the IC-VAEC and JAERI. As another channel of dose intercomparison with IAEA, alanine dosimeters issued by IDAS were simultaneously irradiated with the IC-VAEC dichromate dosimeters at IC-VAEC and analyzed by IAEA. Dose intercomparison between IC-VAEC and JAERI results into a good agreement (better than ±2.5%), and IDAS results also show similar agreement within ±3.0%. The uncertainty was self-estimated on the basis of the JAERI alanine dosimetry, and a preliminary value of about 1.86% at a 68% confidence level is established. The results from these intercomparisons and our estimation of the uncertainty are consistent. We hope that our experience is valuable to other countries which do not have dosimetry standard laboratories and/or are planning to establish them. (author)

Adaptation of penelope Monte Carlo code system to the absorbed dose metrology: characterization of high energy photon beams and calculations of reference dosimeter correction factors; Adaptation du code Monte Carlo penelope pour la metrologie de la dose absorbee: caracterisation des faisceaux de photons X de haute energie et calcul de facteurs de correction de dosimetres de reference

Energy Technology Data Exchange (ETDEWEB)

Mazurier, J

1999-05-28

This thesis has been performed in the framework of national reference setting-up for absorbed dose in water and high energy photon beam provided with the SATURNE-43 medical accelerator of the BNM-LPRI (acronym for National Bureau of Metrology and Primary standard laboratory of ionising radiation). The aim of this work has been to develop and validate different user codes, based on PENELOPE Monte Carlo code system, to determine the photon beam characteristics and calculate the correction factors of reference dosimeters such as Fricke dosimeters and graphite calorimeter. In the first step, the developed user codes have permitted the influence study of different components constituting the irradiation head. Variance reduction techniques have been used to reduce the calculation time. The phase space has been calculated for 6, 12 and 25 MV at the output surface level of the accelerator head, then used for calculating energy spectra and dose distributions in the reference water phantom. Results obtained have been compared with experimental measurements. The second step has been devoted to develop an user code allowing calculation correction factors associated with both BNM-LPRI's graphite and Fricke dosimeters thanks to a correlated sampling method starting with energy spectra obtained in the first step. Then the calculated correction factors have been compared with experimental and calculated results obtained with the Monte Carlo EGS4 code system. The good agreement, between experimental and calculated results, leads to validate simulations performed with the PENELOPE code system. (author)

Pre-1989 epidemiological surveys of low-level dose pre-conception irradiation

International Nuclear Information System (INIS)

Rose, K.S.B.

1990-01-01

Information from 59 pre-1989 epidemiological surveys concerning pre-conception irradiation at doses less than 0.1 Gy has been collated to determine whether any consistent patterns of health effects emerge. The surveys are considered in three groups: childhood malignancies, Down's syndrome and indicators of reproductive damage. Although a pattern is observed for Down's syndrome, no reliable associations are apparent for childhood malignancies (where all surveys pre-date the Gardner survey at Sellafield) or indications of reproductive damage. The twelve surveys of Down's syndrome in relation to maternal pre-conception irradiation received for medical reasons show a pattern consistent with a doubling dose of about 20 mGy. This doubling dose value is, however, not based on individual measurements of ovarian dose and is inconsistent with results from high-level dose surveys. There is no association between paternal irradiation and Down's syndrome. (author)

Forget the Desk Job: Current Roles and Responsibilities in Entry-Level Reference Job Advertisements

Science.gov (United States)

Detmering, Robert; Sproles, Claudene

2012-01-01

This study examines the evolving roles and responsibilities of entry-level academic reference positions, as stated in recent job advertisements posted on the American Library Association's JobLIST Web site and other sources. Findings from a content analysis of these advertisements indicate that current entry-level reference positions in academic…

Receptor dose and patient dose in radiographic exposures: a 15 year review

International Nuclear Information System (INIS)

Peet, D.J.; Tyler, N.; Pryor, M.; Hollaway, P.; Strudley, C.; Leavesley, L.

2008-01-01

A patient dose programme has been established locally for the last 15 years across 109 hospitals and 250 X-ray rooms in line with the National Protocol, in conjunction with a programme to look at routine performance of these rooms. Routine performance checks initially looked primarily at film density and AEC performance but with the introduction of Computerised Radiography (CR) across UK hospitals and a revision of recommended procedures in the UK, the emphasis has shifted to assessing receptor dose under AEC control. Results show a wide variation in film density in the early years indicating sub optimal performance and dose. The spread was reduced over later years. The introduction of CR has led to a variety of approaches by the CR companies, X-ray companies and local sites. Receptor doses vary widely as a result. Large variations within hospitals were also observed. The doses over the last 15 years are reviewed and compared against diagnostic reference levels and with the performance of the imaging chain. Results show that patient dose programmes and optimisation strategies were having an impact, but the introduction of CR requires renewed efforts to ensure images and doses are optimised. (author)

Radiation doses and risks from internal emitters

International Nuclear Information System (INIS)

Harrison, John; Day, Philip

2008-01-01

This review updates material prepared for the UK Government Committee Examining Radiation Risks from Internal Emitters (CERRIE) and also refers to the new recommendations of the International Commission on Radiological Protection (ICRP) and other recent developments. Two conclusions from CERRIE were that ICRP should clarify and elaborate its advice on the use of its dose quantities, equivalent and effective dose, and that more attention should be paid to uncertainties in dose and risk estimates and their implications. The new ICRP recommendations provide explanations of the calculation and intended purpose of the protection quantities, but further advice on their use would be helpful. The new recommendations refer to the importance of understanding uncertainties in estimates of dose and risk, although methods for doing this are not suggested. Dose coefficients (Sv per Bq intake) for the inhalation or ingestion of radionuclides are published as reference values without uncertainty. The primary purpose of equivalent and effective dose is to enable the summation of doses from different radionuclides and from external sources for comparison with dose limits, constraints and reference levels that relate to stochastic risks of whole-body radiation exposure. Doses are calculated using defined biokinetic and dosimetric models, including reference anatomical data for the organs and tissues of the human body. Radiation weighting factors are used to adjust for the different effectiveness of different radiation types, per unit absorbed dose (Gy), in causing stochastic effects at low doses and dose rates. Tissue weighting factors are used to take account of the contribution of individual organs and tissues to overall detriment from cancer and hereditary effects, providing a simple set of rounded values chosen on the basis of age- and sex-averaged values of relative detriment. While the definition of absorbed dose has the scientific rigour required of a basic physical quantity

The Thule accident: Assessment of radiation doses from terrestrial radioactive contamination

International Nuclear Information System (INIS)

Ulbak, K.

2011-12-01

Risoe DTU has carried out research on the terrestrial contamination in the Thule area after the radioactive contents of four nuclear weapons were dispersed following the crash of an American B-52 bomber in 1968. The results of Risoe DTU's studies are described in the report Thule-2007 - Investigation of radioactive pollution on land, which covers all measurements that were carried out on land in Thule in the years 2003, 2006, 2007 and 2008. The present report uses Risoe DTU's report as a basis for assessing radiation doses and consequently the risk for individuals as a result of terrestrial radioactive contamination in the Thule area. The assessment of radiation doses involves a number of conservative assumptions, estimates, and measurements, all of which are subject to considerable uncertainty. In some cases, models have been used based on experiences from other contaminated areas elsewhere in the world, which are subject to climatic and other conditions that diverge from those in the Thule area. The calculated doses are thus associated with considerable uncertainty, which must be taken into account when the results are used for comparison and when the risks of staying in the Thule area are assessed. It has therefore been chosen to provide the assessed radiation doses in the form of indicative orders of magnitude, which are applicable to everyone who might stay in the area, across various age groups. If the estimated doses in this report are combined with the National Institute of Radiation Protections recommended reference level for contamination as a result of the Thule Accident of 1 mSv/year, the assessed magnitudes of radiation doses for inhalation and ingestion as exposure pathways are many orders of magnitude below the reference level (10,00010 million times smaller). The wound contamination exposure pathway has a magnitude of radiation dose that is smaller than the reference level by a factor of 101000, and it should be recalled that the probability of this

The Thule accident: Assessment of radiation doses from terrestrial radioactive contamination

Energy Technology Data Exchange (ETDEWEB)

Ulbak, K. (National Institute of Radiation Protection, Herlev (Denmark))

2011-12-15

Risoe DTU has carried out research on the terrestrial contamination in the Thule area after the radioactive contents of four nuclear weapons were dispersed following the crash of an American B-52 bomber in 1968. The results of Risoe DTU's studies are described in the report Thule-2007 - Investigation of radioactive pollution on land, which covers all measurements that were carried out on land in Thule in the years 2003, 2006, 2007 and 2008. The present report uses Risoe DTU's report as a basis for assessing radiation doses and consequently the risk for individuals as a result of terrestrial radioactive contamination in the Thule area. The assessment of radiation doses involves a number of conservative assumptions, estimates, and measurements, all of which are subject to considerable uncertainty. In some cases, models have been used based on experiences from other contaminated areas elsewhere in the world, which are subject to climatic and other conditions that diverge from those in the Thule area. The calculated doses are thus associated with considerable uncertainty, which must be taken into account when the results are used for comparison and when the risks of staying in the Thule area are assessed. It has therefore been chosen to provide the assessed radiation doses in the form of indicative orders of magnitude, which are applicable to everyone who might stay in the area, across various age groups. If the estimated doses in this report are combined with the National Institute of Radiation Protection's recommended reference level for contamination as a result of the Thule Accident of 1 mSv/year, the assessed magnitudes of radiation doses for inhalation and ingestion as exposure pathways are many orders of magnitude below the reference level (10,000-10 million times smaller). The wound contamination exposure pathway has a magnitude of radiation dose that is smaller than the reference level by a factor of 10-1000, and it should be recalled that the

Effect of Exposure to Pill Contraceptive Low-dose Levels of Homocysteine and Nitric Oxide in Healthy Women

Directory of Open Access Journals (Sweden)

A Dehghani

2016-07-01

Full Text Available Introduction: Cardiovascular disease is one of the public health priorities. Consumption of oral contraceptives increase the risk of cardiovascular disease and it still remains a concern. This study aimed to investigate the effect of exposure on pill contraceptive low-dose  levels on homocysteine and nitric oxide. methods: In this cohort ( retrospective+ prospective study, 100 women with normal menstrual cycle aged betwen 20-35 years old refered to health care centers of Yazd, Iran in 2015.  This study was conducted through face to face interviews by the researcher who asked for demographic and anthropometric characteristics. Anthropometic indices  was measured and the levels of homosysteine and nitric oxide was determined. The data were analyzed using t-test, chi- square test and ANOVA by SPSS 21. Results: The mean and standard deviation of homocysteine levels in the exposed group acompared to non-exposed group were (3/848±2/357 μmol/L and (3/284±1/616 μmol/L as well as the mean and standard deviation of nitric oxide in the exposed group were (p-value=0/41 and (181/360±90/44μM and in the non-exposed group were (162/654±90/913 μM and (p-value=0/29 , respectively.According to these results, there was not found any statistical significant  difference among these results. Conclusion: Taking low dose oral contraceptives in healthy women did not change any differences in homocysteine and nitric oxide levels as a modifiable risk factors for cardiovascular disease.

Effects of irradiation source and dose level on quality characteristics of processed meat products

Science.gov (United States)

Ham, Youn-Kyung; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Choi, Yun-Sang; Song, Beom-Seok; Park, Jong-Heum; Kim, Cheon-Jei

2017-01-01

The effect of irradiation source (gamma-ray, electron-beam, and X-ray) and dose levels on the physicochemical, organoleptic and microbial properties of cooked beef patties and pork sausages was studied, during 10 days of storage at 30±1 °C. The processed meat products were irradiated at 0, 2.5, 5, 7.5, and 10 kGy by three different irradiation sources. The pH of cooked beef patties and pork sausages was unaffected by irradiation sources or their doses. The redness of beef patties linearly decreased with increasing dose level (Pchanges in overall acceptability were observed for pork sausages regardless of irradiation source (P>0.05), while gamma-ray irradiated beef patties showed significantly decreased overall acceptability in a dose-dependent manner (Poxidation of samples was accelerated by irradiation depending on irradiation sources and dose levels during storage at 30 °C. E-beam reduced total aerobic bacteria of beef patties more effectively, while gamma-ray considerably decreased microbes in pork sausages as irradiation dose increased. The results of this study indicate that quality attributes of meat products, in particular color, lipid oxidation, and microbial properties are significantly influenced by the irradiation sources.

Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

Science.gov (United States)

Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

2012-03-01

Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

Construction of Chinese reference female phantom

International Nuclear Information System (INIS)

Sheng Yinxiangzi; Liu Lixing; Xia Xiaobin

2013-01-01

In this study, a Voxel-based Chinese Reference female Phantom (VCRP-woman) is developed from an individual female phantom which was based on high resolution cross-sectional color photographs. An in-house C ++ program was developed to adjust the phantom. Finally, a reference female phantom with have the same height, weighte and similar organs masses with the Chinese reference adult female data. The adjusted phantom is then imported to MCNPX to calculate the organs absorbed dose and effective dose conversion coefficients. Results are compared between VCRP-woman and the ICRP adult reference female phantom. (authors)

Comparison of two dose regimens of growth hormone (GH) with different target IGF-1 levels on glucose metabolism, lipid profile, cardiovascular function and anthropometric parameters in gh-deficient adults.

Science.gov (United States)

Cenci, Maria Claudia Peixoto; Soares, Débora Vieira; Spina, Luciana Diniz Carneiro; Brasil, Rosane Resende de Lima Oliveira; Lobo, Priscila Marise; Michmacher, Eduardo; Vaisman, Mario; Boguszewski, Cesar Luiz; Conceição, Flávia Lúcia

2012-01-01

To compare the effects of two regimens of GH therapy with different target IGF-1 levels on anthropometric parameters, glucose metabolism, lipid profile and cardiac function in adults with GH deficiency (GHD). Retrospective analysis of 14 GHD adults from Clementino Fraga Filho University Hospital, Rio de Janeiro, Brazil, who were treated with a GH regimen aimed at maintaining serum IGF-1 levels between the median and upper reference limit (high dose group - HDGH) and 18 GHD adults from Federal University Hospital, Curitiba, Brazil, who received a fixed GH dose of 0.2mg/day in the first year of treatment, followed by titration to maintain serum IGF-1 levels between the median and lower reference limit (low dose group - LDGH). All patients were followed for 2 years with analysis of anthropometric parameters, serum levels of IGF-1, glucose, insulin, HOMA-IR, lipid profile, and transthoracic echocardiography. Changes on weight, BMI and waist circumference were similar between the two groups. Insulin levels increased and HOMA-IR worsened in the LDGH group at 1year and improved thereafter. Total cholesterol and triglycerides did not change with therapy. LDL cholesterol reduced in both groups, while HDL-cholesterol significantly increased only in the HDGH group (p=0.007 vs LDGH). No significant variations on echocardiographic parameters were observed. The HDGH and LDGH regimens resulted in similar changes on anthropometric, echocardiographic, glucose and lipid parameters in GHD adults, except for increase in HDL cholesterol that was only observed in the HDGH regimen. Copyright © 2012 Elsevier Ltd. All rights reserved.

SU-E-P-08: Establishment of Local Diagnostic Reference Levels of Routine Abdomen Exam in Computed Tomography According to Body Weight

International Nuclear Information System (INIS)

Wang, H; Wang, Y; Weng, H

2015-01-01

Purpose: The national diagnostic reference levels (NDRLs) is an efficient, concise and powerful standard for optimizing radiation protection of a patient. However, for each hospital the dose-reducing potential of focusing on establishment of local DRLs (LDRLs). A lot of study reported that Computed tomography exam contributed majority radiation dose in different medical modalities, therefore, routine abdomen CT exam was choose in initial pilot study in our study. Besides the mAs of routine abdomen CT exam was decided automatic exposure control by linear attenuation is relate to body shape of patient. In this study we would like to establish the local diagnostic reference levels of routine abdomen exam in computed tomography according to body weight of patient. 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). The patient sample involved 82 adult patients of both sexes and divided into three groups by their body weight (50–60 kg, 60–70 kg, 70–80 kg).Carried out the routine abdomen examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. The average values were compared with the European DRLs. Results: The majority of patients (75%) were between 50–70 Kg of body weight, the numbers of patient in each group of weight were 40–50:7; 50–60:29; 60–70:33; 70–80:13. The LDRLs in each group were 10.81mGy, 14.46mGy, 20.27mGy and 21.04mGy, respectively. The DLP were 477mGy, 630mGy, 887mGy and 959mGy, respectively. No matter which group the LDRLs were lower than European DRLs. Conclusions: We would like to state that this was a pioneer work in local hospital in Chiayi. We hope that this may lead the way to further developments in Taiwan

SU-E-P-08: Establishment of Local Diagnostic Reference Levels of Routine Abdomen Exam in Computed Tomography According to Body Weight

Energy Technology Data Exchange (ETDEWEB)

Wang, H; Wang, Y; Weng, H [Chiayi Chang Gung Memorial Hospital of The C.G.M.F, Puzi City, Chiayi County, Taiwan (China)

2015-06-15

Purpose: The national diagnostic reference levels (NDRLs) is an efficient, concise and powerful standard for optimizing radiation protection of a patient. However, for each hospital the dose-reducing potential of focusing on establishment of local DRLs (LDRLs). A lot of study reported that Computed tomography exam contributed majority radiation dose in different medical modalities, therefore, routine abdomen CT exam was choose in initial pilot study in our study. Besides the mAs of routine abdomen CT exam was decided automatic exposure control by linear attenuation is relate to body shape of patient. In this study we would like to establish the local diagnostic reference levels of routine abdomen exam in computed tomography according to body weight of patient. 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). The patient sample involved 82 adult patients of both sexes and divided into three groups by their body weight (50–60 kg, 60–70 kg, 70–80 kg).Carried out the routine abdomen examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. The average values were compared with the European DRLs. Results: The majority of patients (75%) were between 50–70 Kg of body weight, the numbers of patient in each group of weight were 40–50:7; 50–60:29; 60–70:33; 70–80:13. The LDRLs in each group were 10.81mGy, 14.46mGy, 20.27mGy and 21.04mGy, respectively. The DLP were 477mGy, 630mGy, 887mGy and 959mGy, respectively. No matter which group the LDRLs were lower than European DRLs. Conclusions: We would like to state that this was a pioneer work in local hospital in Chiayi. We hope that this may lead the way to further developments in Taiwan.

Determination of indoor radon concentration levels and the associated annual effective dose rate in some Ghanaian dwellings

International Nuclear Information System (INIS)

Nsiah-Akoto, I.

2010-01-01

cancer risk increased with indoor radon concentration. The odds ratio for the present study at 95% confidence interval was 7 (CI 0.92 - 53.16). 0.13(CI 0.02 - 0.73), 0.20 (CI0.02 - 2.39), 5.5 (CI 0.88 - 34.46), 0.25 (CI 0.05 - 1.26), 0.38(CI 0.12 - 1.22) were ORs and 95% confidence interval for the previous studies respectively. Using the BEIR III model, 5 cases of lung cancer was estimated. These results show that the indoor radon level in the present study has increased tremendously as compared to the same study area 20years ago. Though most of the houses have radon activity in the range of intervention level (200-600) Bq/m3 as recommended by ICRP (1993) and the annual effective dose in the ICRP recommendations (3mSv/y-l0mSv/y), a lot more studies needs to be done to come out with a national reference level. The radon activity has not only been found to vary with the construction mode of houses but also with the ventilation conditions and the geology of the area. The results obtained also give a correlation between indoor radon levels and the associated level of risk. (au)

Adduction of acrylamide with biomacromolecules at environmental dose level measured by accelerator mass spectrometry (AMS)

International Nuclear Information System (INIS)

Xie, Q.Y.; Sun, H.F.; Liu, Y.F.; Ding, X.F.; Fu, D.P.; Liu, K.X.

2005-01-01

Acrylamide (AA) is a well-known neurotoxin, which also has developmental, reproductive as well as genetic toxicity. AA has been classified as a probable human carcinogen by IARC in 1994 since its carcinogenic effects in animals were reported after repetitive high level dosing. Over the last 10 years, there have been a large number of studies investigating the effects of AA on rodent reproductive performance. In 2002, the Swedish Food Administration reported the presence of AA in the heat-treated food products. which again elicited great concern on the toxicity of AA. However most of these studies were investigated at a dose level of mg/kg b.w and above, which is much higher than the actual human relevant dose. In this study we investigate the adduction of environmental level AA with biomacromolecules by the ultra-sensitive AMS technique. This may provide some information on the reproductive toxicity of AA under extremely low level exposure. A series doses of [2, 3- 14 C] AA (0, 0.1, 1, 10, 100, 250, 1000 μg/kg bw) were administrated with a single intraperitoneal injection (i.p.) to ICR adult male mice. The blood and spermatozoon were collected 24 h post dosing. Hemoglobin (Hb), serum albumin (SA), protamine, spermatozoon DNA, spermatozoon head and tail were isolated respectively, and then transformed into graphite following our previous procedure, The adduct levels were determined by a 0.6 MV compact AMS facility at the Institute of Heavy Ion Physics of Peking University. The results indicate that: (1) AA adduct number increases with the doses within 0.1-1000 μg/kg b.w. range in a log/log linear mode, except for DNA within 10-1000 μg/kg b.w. range. (2) Comparing protamine, Hb, and SA adducts with that of spermatozoon DNA (see Fig. 1), AA mainly adducts to proteins. For instance, at 1000 μg/kg b.w. dose level, spermatozoon DNA adducts only account for about 0.71%, 1.36% and 0.82% of protamine, Hb and SA adducts, respectively. (3) AA-protamine adducts, AA

Dose evaluation in medical staff during diagnostics procedures in interventional radiology; Avaliacao da dose na equipe medica durante procedimentos diagnoticos de radiologia intervencionista

Energy Technology Data Exchange (ETDEWEB)

Bacchim Neto, Fernando A.; Alves, Allan F.F.; Rosa, Maria E.D.; Miranda, Jose R.A. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias. Departamento de Fisica e Biofisica; Moura, Regina [Faculdade de Medicina de Botucatu, SP (Brazil). Departamento de Cirurgia e Ortopedia; Pina, Diana R., E-mail: bacchim@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina. Departamento de Doencas Tropicais e Diagnostico por Imagem

2014-08-15

Studies show that personal dosimeters may underestimate the dose values in interventional physicians, especially in extremities and crystalline. The objective of this work was to study the radiation exposure levels of medical staff in diagnostic interventional radiology procedures. For this purpose LiF:Mg,Ti (TLD-100) dosimeters were placed in different regions of the physician body. When comparing with reference dose levels, the maximum numbers of annual procedures were found. This information is essential to ensure the radiological protection of those professionals. (author)

Radiation doses to patients receiving computed tomography examinations in British Columbia

International Nuclear Information System (INIS)

Aldrich, J.E.; Bilawich, A.-M.; Mayo, J.R.

2006-01-01

To estimate the diagnostic reference levels and effective radiation dose to patients from routine computed tomography (CT) examinations in the province of British Columbia, Canada. The patient weight, height and computed tomography dose index or dose linear product (DLP) were recorded on study sheets for 1070 patients who were referred for clinically indicated routine CT examinations at 18 radiology departments in British Columbia. Sixteen of the scanners were multidetector row scanners. The average patient dose varied from hospital to hospital. The largest range was found for CT of the abdomen, for which the dose varied from 3.6 to 26.5 (average 10.1) mSv. For head CT, the range was 1.7 to 4.9 (average 2.8) mSv; for chest CT, it was 3.8 to 26 (average 9.3) mSv; for pelvis CT, it was 3.5 to 15.5 (average 9.0) mSv; and for abdomen/pelvis CT, it was 7.3 to 31.5 (average 16.3) mSv. Reference dose values were calculated for each exam. These DLP values are as follows: head, 1300 mGy cm; chest, 600 mGy cm; abdomen, 920 mGy cm; pelvis, 650 mGy cm; and abdomen/pelvis, 1100 mGy cm. Among hospitals, there was considerable variation in the DLP and patient radiation dose for a specific exam. Reference doses and patient doses were higher than those found in similar recent surveys carried out in the United Kingdom and the European Union. Patient doses were similar to those found in a recent survey in Germany. (author)

Modelling of Biota Dose Effects. Report of Working Group 6 Biota Dose Effects Modelling of EMRAS II Topical Heading Reference Approaches for Biota Dose Assessment. Environmental Modelling for RAdiation Safety (EMRAS II) Programme

International Nuclear Information System (INIS)

2014-07-01

Environmental assessment models are used for evaluating the radiological impact of actual and potential releases of radionuclides to the environment. They are essential tools for use in the regulatory control of routine discharges to the environment and in planning the measures to be taken in the event of accidental releases. They are also used for predicting the impact of releases which may occur far into the future, for example, from underground radioactive waste repositories. It is important to verify, to the extent possible, the reliability of the predictions of such models by a comparison with measured values in the environment or with the predictions of other models. The IAEA has been organizing programmes on international model testing since the 1980s. These programmes have contributed to a general improvement in models, in the transfer of data and in the capabilities of modellers in Member States. IAEA publications on this subject over the past three decades demonstrate the comprehensive nature of the programmes and record the associated advances which have been made. From 2009 to 2011, the IAEA organized a project entitled Environmental Modelling for RAdiation Safety (EMRAS II), which concentrated on the improvement of environmental transfer models and the development of reference approaches to estimate the radiological impacts on humans, as well as on flora and fauna, arising from radionuclides in the environment. Different aspects were addressed by nine working groups covering three themes: reference approaches for human dose assessment, reference approaches for biota dose assessment and approaches for addressing emergency situations. This publication describes the work of the Biota Effects Modelling Working Group

Modelling of Biota Dose Effects. Report of Working Group 6 Biota Dose Effects Modelling of EMRAS II Topical Heading Reference Approaches for Biota Dose Assessment. Environmental Modelling for RAdiation Safety (EMRAS II) Programme

Energy Technology Data Exchange (ETDEWEB)

NONE

2014-07-15

Environmental assessment models are used for evaluating the radiological impact of actual and potential releases of radionuclides to the environment. They are essential tools for use in the regulatory control of routine discharges to the environment and in planning the measures to be taken in the event of accidental releases. They are also used for predicting the impact of releases which may occur far into the future, for example, from underground radioactive waste repositories. It is important to verify, to the extent possible, the reliability of the predictions of such models by a comparison with measured values in the environment or with the predictions of other models. The IAEA has been organizing programmes on international model testing since the 1980s. These programmes have contributed to a general improvement in models, in the transfer of data and in the capabilities of modellers in Member States. IAEA publications on this subject over the past three decades demonstrate the comprehensive nature of the programmes and record the associated advances which have been made. From 2009 to 2011, the IAEA organized a project entitled Environmental Modelling for RAdiation Safety (EMRAS II), which concentrated on the improvement of environmental transfer models and the development of reference approaches to estimate the radiological impacts on humans, as well as on flora and fauna, arising from radionuclides in the environment. Different aspects were addressed by nine working groups covering three themes: reference approaches for human dose assessment, reference approaches for biota dose assessment and approaches for addressing emergency situations. This publication describes the work of the Biota Effects Modelling Working Group.

Derived reference levels for prenatal exposure in a radiological emergency

International Nuclear Information System (INIS)

Nuccetelli, C.; Risica, S.; Rogani, A.

2002-01-01

After the Chernobyl accident many countries renewed their radiological emergency plans, also considering the possibility of over boundary accidents. This has been set out by the 96/29/Euratom Directive (Council Directive, 1996), which states that E ach Member State shall ensure that account is taken of the fact that radiological emergencies may occur in connection with practices on or outside its territory and affect it . Moreover, after September 11, 2001, the need to prepare emergency plans for possible terroristic attacks became evident and these plans are now being worked out in many countries for intervention in case of biological, chemical and/or radiological risk. In the event of radiological emergency, all decisions to be taken are based on possible doses to critical groups (European Commission, 1997), which are the population groups most at risk. These critical groups are, in most cases, infants or children, given that dose coefficients for these age groups are generally higher than for adults. However, a new ICRP Recommendation (ICRP, 2001) has recently been published that gives dose coefficients for embryo/foetus due to intake by the mother, by inhalation or ingestion, of 31 radionuclides. Also as a result of the revaluation in the last years of the possible health effects of prenatal exposure to ionising radiation (see e.g. the review in P. Fattibene et al., 1999), the consequences for the embryo/foetus of a possible radiological emergency connected to a nuclear plant and to possible dispersion of Depleted Uranium (DU) in the environment are analysed and discussed in this paper. For the former type of accident, Derived Intervention Levels (DILs) are calculated for prenatal exposure due to acute inhalation by the mother (female member of the public) and an assessment is performed of ingestion doses for the offspring resulting from consumption of foodstuffs by the mother of which 10% of the annual consumption is contaminated at the maximum levels

A simple method for conversion of airborne gamma-ray spectra to ground level doses

DEFF Research Database (Denmark)

Korsbech, Uffe C C; Bargholz, Kim

1996-01-01

A new and simple method for conversion of airborne NaI(Tl) gamma-ray spectra to dose rates at ground level has been developed. By weighting the channel count rates with the channel numbers a spectrum dose index (SDI) is calculated for each spectrum. Ground level dose rates then are determined...... by multiplying the SDI by an altitude dependent conversion factor. The conversion factors are determined from spectra based on Monte Carlo calculations. The results are compared with measurements in a laboratory calibration set-up. IT-NT-27. June 1996. 27 p....

Determination of effective dose rate reference values in São José do Sabugi, PB, Brazil

International Nuclear Information System (INIS)

Medeiros, Nilson V. da S.; Santos Júnior, José A. dos; Amaral, Romilton dos S.; Santos, Josineide M. do N.; Araújo, Eduardo E.N. de; Santos Junior, Otávio P. dos; Correia, Filipe L. de B.; Silveira, Patrícia B.

2017-01-01

Brazil has some areas with elevated concentration of uranium and/or thorium, such as Guarapari in the State of Espírito Santo, Poços de Caldas in Minas Gerais and regions between the States of Pernambuco and Paraíba.The Seridó region, in the State of Paraiba, consists of rocks classified as pegmatites, gneisses and feldspars, with high level of uranium ores. The high levels of primordial radionuclides have been the focus of the studies performed in the area, specifically in the uranium deposit of Espinharas and some adjacent municipalities. The aim of this work was to carry out 'in situ' measurements in the city of São José do Sabugi, Paraíba. Measurements were done using a portable gamma discriminator with combined NaI (Tl) and BGO probe, coupled to a motor vehicle that allowed to monitor 520 points in the urban and rural areas of said municipality, obtaining effective dose rates ranging from 0.7 to 1.56 mSv.y -1 and averages of 0.26 mSv.y -1 and 0.87 mSv.y -1 , respectively. The results obtained for radiometry of this municipality allow to conclude that the urban and rural areas meet the criteria established by UNSCEAR for areas considered as low background radiation. With this work, reference parameters were established for radiometric characterization of the surrounding municipalities to the uranium deposit of Espinharas. (author)

Determination of effective dose rate reference values in São José do Sabugi, PB, Brazil

Energy Technology Data Exchange (ETDEWEB)

Medeiros, Nilson V. da S.; Santos Júnior, José A. dos; Amaral, Romilton dos S.; Santos, Josineide M. do N.; Araújo, Eduardo E.N. de; Santos Junior, Otávio P. dos; Correia, Filipe L. de B., E-mail: nilson.medeiros@ufpe.br, E-mail: jaraujo@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Grupo de Radioecologia; Rojas, Lino A.V., E-mail: linomarvic@gmail.com [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear, La Habana (Cuba); Silveira, Patrícia B., E-mail: pbrandao@cnen.gov.br [Centro Regional de Ciências Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2017-07-01

Brazil has some areas with elevated concentration of uranium and/or thorium, such as Guarapari in the State of Espírito Santo, Poços de Caldas in Minas Gerais and regions between the States of Pernambuco and Paraíba.The Seridó region, in the State of Paraiba, consists of rocks classified as pegmatites, gneisses and feldspars, with high level of uranium ores. The high levels of primordial radionuclides have been the focus of the studies performed in the area, specifically in the uranium deposit of Espinharas and some adjacent municipalities. The aim of this work was to carry out 'in situ' measurements in the city of São José do Sabugi, Paraíba. Measurements were done using a portable gamma discriminator with combined NaI (Tl) and BGO probe, coupled to a motor vehicle that allowed to monitor 520 points in the urban and rural areas of said municipality, obtaining effective dose rates ranging from 0.7 to 1.56 mSv.y{sup -1} and averages of 0.26 mSv.y{sup -1}and 0.87 mSv.y{sup -1}, respectively. The results obtained for radiometry of this municipality allow to conclude that the urban and rural areas meet the criteria established by UNSCEAR for areas considered as low background radiation. With this work, reference parameters were established for radiometric characterization of the surrounding municipalities to the uranium deposit of Espinharas. (author)

The Influence of the Terrestrial Reference Frame on Studies of Sea Level Change

Science.gov (United States)

Nerem, R. S.; Bar-Sever, Y. E.; Haines, B. J.; Desai, S.; Heflin, M. B.

2015-12-01

The terrestrial reference frame (TRF) provides the foundation for the accurate monitoring of sea level using both ground-based (tide gauges) and space-based (satellite altimetry) techniques. For the latter, tide gauges are also used to monitor drifts in the satellite instruments over time. The accuracy of the terrestrial reference frame (TRF) is thus a critical component for both types of sea level measurements. The TRF is central to the formation of geocentric sea-surface height (SSH) measurements from satellite altimeter data. The computed satellite orbits are linked to a particular TRF via the assumed locations of the ground-based tracking systems. The manner in which TRF errors are expressed in the orbit solution (and thus SSH) is not straightforward, and depends on the models of the forces underlying the satellite's motion. We discuss this relationship, and provide examples of the systematic TRF-induced errors in the altimeter derived sea-level record. The TRF is also crucial to the interpretation of tide-gauge measurements, as it enables the separation of vertical land motion from volumetric changes in the water level. TRF errors affect tide gauge measurements through GNSS estimates of the vertical land motion at each tide gauge. This talk will discuss the current accuracy of the TRF and how errors in the TRF impact both satellite altimeter and tide gauge sea level measurements. We will also discuss simulations of how the proposed Geodetic Reference Antenna in SPace (GRASP) satellite mission could reduce these errors and revolutionize how reference frames are computed in general.

Measurements of computed tomography dose index for axial and spiral CT scanners

International Nuclear Information System (INIS)

Breiki, G; Abbas, Y.; Diab, H.M.; Gomaa, M

2007-01-01

The energy deposited in the patient by the rotating x-ray beam in computed tomography produces more uniform absorbed dose values within the section of imaged tissue than those produced in conventional radiological procedures. The dose values within a specific section are determined by factors such as voltage, current, scan field, rotation angle, filtration, collimation, and section thickness and spacing. This study is a part of extensive project, aiming to investigate practice of computed tomography at various hospitals and to implement a Reference Dose Levels (RDLs) to routine CT examinations in Egypt. The dosimetric quantities proposed in the European Guidelines (EG) for CT are weighted computed tomography dose index (CTDI w ) for a single slice and dose-length product (DLP) for a complete examination. Patient-related data as well as technical parameters for head, chest, abdomen and pelvis examinations were collected for seven CT scanners in public and private hospitals.Dose measurements were performed for both axial and spiral models for a range of CT examinations using CT dosimetry head and body phantoms, and ion chamber designed for CT dosimetry. The determined CTDI w and DLP values were compared with the European Commission reference dose levels (ECRDLs) and also with some international survey results. Mean values of CTDI w had a range of 36-69 m Gy with average 55 m Gy for head, and 11-35 mGy with average 23 mGy for chest, abdomen and pelvis examinations. The current reference CTDI w values are 60 m Gy for adult head and 25 m Gy for adult Abdomen

Analysis of CT radiation dose based on radiation-dose-structured reports

International Nuclear Information System (INIS)

Wang Weipeng; Zhang Yi; Zhang Menglong; Zhang Dapeng; Song Shaojuan

2014-01-01

Objective: To analyse the CT radiation dose statistically using the standardized radiation-dose-structured report (RDSR) of digital imaging and communications in medicine (DICOM). Methods: Using the self-designed software, 1230 RDSR files about CT examination were obtained searching on the picture archiving and communication system (PACS). The patient dose database was established by combination of the extracted relevant information with the scanned sites. The patients were divided into adult group (over 10 years) and child groups (0-1 year, 1-5 years, 5-10 years) according to the age. The average volume CT dose index (CTDI vol ) and dose length product (DLP) of all scans were recorded respectively, and then the effective dose (E) was estimated. The DLP value at 75% quantile was calculated and compared with the diagnostic reference level (DRL). Results: In adult group, CTDI vol and DLP values were moderately and positively correlated (r = 0.41), the highest E was observed in upper abdominal enhanced scan, and the DLP value at 75% quantile was 60% higher than DRL. In child group, their CTDI vol in group of 5-10 years was greater than that in groups of 0-1 and 1-5 years (t = 2.42, 2.04, P < 0.05); the DLP value was slightly and positively correlated with the age (r = 0.16), while E was moderately and negatively correlated with the age (r = -0.48). Conclusions: It is a simple and efficient method to use RDSR to obtain the radiation doses of patients. With the popularization of the new equipment and the application of regionalized medical platform, RDSR would become the main tool for the dosimetric level surveying and individual dose recording. (authors)

Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

Energy Technology Data Exchange (ETDEWEB)

Messerli, Michael, E-mail: Michael.Messerli@usz.ch [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Kluckert, Thomas; Knitel, Meinhard [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Rengier, Fabian [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany); Warschkow, René [Department of Surgery, Cantonal Hospital St. Gallen (Switzerland); Alkadhi, Hatem [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Leschka, Sebastian [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland); Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University Zurich (Switzerland); Wildermuth, Simon; Bauer, Ralf W. [Division of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen (Switzerland)

2016-12-15

Highlights: • Computer-aided detection (CAD) of solid pulmonary nodules was compared in 202 patients in standard dose and ultralow dose CT. • The per–nodule sensitivity of CAD was 70% in standard dose CT and 68% in ultralow dose CT. • The per–nodule sensitivity of CAD in standard dose CT was similar to ultralow dose CT in all size subgroups (all p > 0.05). • Adding CAD markings in ultralow dose CT significantly improved the sensitivity of two radiologists from 77% to 88% and from 66% to 79%, respectively. • CAD can serve as an excellent second reader for nodule detection in CT even at dose levels similar to chest X-ray. - Abstract: Objectives: To determine the value of computer-aided detection (CAD) for solid pulmonary nodules in ultralow radiation dose single-energy computed tomography (CT) of the chest using third-generation dual-source CT at 100 kV and fixed tube current at 70 mAs with tin filtration. Methods: 202 consecutive patients undergoing clinically indicated standard dose chest CT (1.8 ± 0.7 mSv) were prospectively included and scanned with an additional ultralow dose CT (0.13 ± 0.01 mSv) in the same session. Standard of reference (SOR) was established by consensus reading of standard dose CT by two radiologists. CAD was performed in standard dose and ultralow dose CT with two different reconstruction kernels. CAD detection rate of nodules was evaluated including subgroups of different nodule sizes (<5, 5–7, >7 mm). Sensitivity was further analysed in multivariable mixed effects logistic regression. Results: The SOR included 279 solid nodules (mean diameter 4.3 ± 3.4 mm, range 1–24 mm). There was no significant difference in per–nodule sensitivity of CAD in standard dose with 70% compared to 68% in ultralow dose CT both overall and in different size subgroups (all p > 0.05). CAD led to a significant increase of sensitivity for both radiologists reading the ultralow dose CT scans (all p < 0.001). In multivariable analysis, the use

Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

International Nuclear Information System (INIS)

Messerli, Michael; Kluckert, Thomas; Knitel, Meinhard; Rengier, Fabian; Warschkow, René; Alkadhi, Hatem; Leschka, Sebastian; Wildermuth, Simon; Bauer, Ralf W.

2016-01-01

Highlights: • Computer-aided detection (CAD) of solid pulmonary nodules was compared in 202 patients in standard dose and ultralow dose CT. • The per–nodule sensitivity of CAD was 70% in standard dose CT and 68% in ultralow dose CT. • The per–nodule sensitivity of CAD in standard dose CT was similar to ultralow dose CT in all size subgroups (all p > 0.05). • Adding CAD markings in ultralow dose CT significantly improved the sensitivity of two radiologists from 77% to 88% and from 66% to 79%, respectively. • CAD can serve as an excellent second reader for nodule detection in CT even at dose levels similar to chest X-ray. - Abstract: Objectives: To determine the value of computer-aided detection (CAD) for solid pulmonary nodules in ultralow radiation dose single-energy computed tomography (CT) of the chest using third-generation dual-source CT at 100 kV and fixed tube current at 70 mAs with tin filtration. Methods: 202 consecutive patients undergoing clinically indicated standard dose chest CT (1.8 ± 0.7 mSv) were prospectively included and scanned with an additional ultralow dose CT (0.13 ± 0.01 mSv) in the same session. Standard of reference (SOR) was established by consensus reading of standard dose CT by two radiologists. CAD was performed in standard dose and ultralow dose CT with two different reconstruction kernels. CAD detection rate of nodules was evaluated including subgroups of different nodule sizes (<5, 5–7, >7 mm). Sensitivity was further analysed in multivariable mixed effects logistic regression. Results: The SOR included 279 solid nodules (mean diameter 4.3 ± 3.4 mm, range 1–24 mm). There was no significant difference in per–nodule sensitivity of CAD in standard dose with 70% compared to 68% in ultralow dose CT both overall and in different size subgroups (all p > 0.05). CAD led to a significant increase of sensitivity for both radiologists reading the ultralow dose CT scans (all p < 0.001). In multivariable analysis, the use

Comparative study of reference points by dosimetric analyses for late complications after uniform external radiotherapy and high-dose-rate brachytherapy for cervical cancer

International Nuclear Information System (INIS)

Chen, S.-W.; Liang, J.-A.; Yeh, L.-S.; Yang, S.-N.; Shiau, A.-C.; Lin, F.-J.

2004-01-01

Purpose: This study aimed to correlate and compare the predictive values of rectal and bladder reference doses of uniform external beam radiotherapy without shielding and high-dose-rate intracavitary brachytherapy (HDRICB) with late sequelae in patients with uterine cervical cancer. Methods and materials: Between September 1992 and December 1998, 154 patients who survived more than 12 months after treatment were studied. Initially, they were treated with 10-MV X-rays (44 to 45 Gy/22 to 25 fractions over 4 to 5 weeks) to the whole pelvis, after which HDRICB was performed using 192 Ir remote afterloading at 1-week intervals for 4 weeks. The standard prescribed dose for each HDRICB was 6.0 Gy to point A. Patient- and treatment-related-factors were evaluated for late rectal complications using logistic regression modeling. Results: The probability of rectal complications showed better correlation of dose-response with increasing total ICRU (International Committee on Radiotherapy Units and Measurements) rectal dose. Multivariate logistic regression demonstrated a high risk of late rectal sequelae in patients who developed rectal complications (p 0.0001;relative risk, 15.06;95% CI, 2.89∼43.7) and total ICRU rectal dose greater than 16 Gy (p = 0.02;relative risk, 2.07;95% CI, 1.13∼4.55). The high risk factors for bladder complications were seen in patients who developed rectal complications (p = 0.0001;relative risk, 15.2;95% CI, 2.81∼44.9) and total ICRU bladder dose greater than 24 Gy (p = 0.02;relative risk, 8.93;95% CI, 1.79∼33.1). Conclusion: This study demonstrated the predictive value of ICRU rectal and bladder reference dosing in HDRICB for patients receiving uniform external beam radiation therapy without central shielding. Patients who had a total ICRU rectal dose greater than 16 Gy, or a total ICRU bladder dose over 24 Gy, were at risk of late sequelae

Proposals for common definitions of reference points in gynecological brachytherapy

International Nuclear Information System (INIS)

Chassagne, D.; Horiot, J.C.

1977-01-01

In May 1975 the report of European Curietherapy Group recommended in gynecological Dosimetry by computer. Use of reference points = lymphatic trapezoid figure with 6 points, Pelvic wall, all points are refering to bony structures. Use of critical organ reference points = maximum rectum dose, bladder dose mean rectal dose. Use of 6,000 rads reference isodose described by height, width, and thickness dimensions. These proposals are the basis of a common language in gynecological brachytherapy [fr

Sci-Fri AM: MRI and Diagnostic Imaging - 02: Quality Improvement: Diagnostic Reference Levels for Interior Health CT exams – L-Spine, Chest/Abdomen/pelvis, Abdomen/Pelvis, Head

Energy Technology Data Exchange (ETDEWEB)

Bjarnason, Thorarin [Diagnostic Imaging / Interior Health, Mathematics, Statistics, Physics & Computer Science / UBCO (Canada); Radiology / UBC (Canada)

2016-08-15

Diagnostic Reference Levels are used to optimize patient dose and image quality in the clinical setting. It is assumed that the majority of exams are of diagnostic quality, or the radiologists would request protocol adjustments. By investigating the dose indicator distributions from all scanners, the upper DRL can be set to the 75th percentile of the distribution and a lower DRL can be set to the 10th percentile. Scanners using doses consistently outside the upper/lower DRL range can be adjusted accordingly. 11 CT scanners, all contributing to the American College of Radiology Dose Index Registry (ACR DIR) were used in this study. Dose indicator data were compiled from the ACR DIR data and local DRLs established. Scanners with median doses outside the upper/lower DRL were followed-up with. Using effective dose and exam volumes, collective dose was determined before and after protocol adjustments to evaluate the effect of this quality improvement effort. The quality initiative is complete for L-spine and Chest/Abdomen/Pelvis exams and only initial surveys were completed for Head and Abdomen/Pelvis examsg. Median Scanner Dose reductions were 8.8 and 4.9 % for L-spine and Chest/Abdomen/Pelvis exams, respectively, resulting with collective dose reductions of 0.7 and 3.2 person•Sv/yr. Follow-up is ongoing for Abdomen/Pelvis and Head exams.

Sci-Fri AM: MRI and Diagnostic Imaging - 02: Quality Improvement: Diagnostic Reference Levels for Interior Health CT exams – L-Spine, Chest/Abdomen/pelvis, Abdomen/Pelvis, Head

International Nuclear Information System (INIS)

Bjarnason, Thorarin

2016-01-01

Diagnostic Reference Levels are used to optimize patient dose and image quality in the clinical setting. It is assumed that the majority of exams are of diagnostic quality, or the radiologists would request protocol adjustments. By investigating the dose indicator distributions from all scanners, the upper DRL can be set to the 75th percentile of the distribution and a lower DRL can be set to the 10th percentile. Scanners using doses consistently outside the upper/lower DRL range can be adjusted accordingly. 11 CT scanners, all contributing to the American College of Radiology Dose Index Registry (ACR DIR) were used in this study. Dose indicator data were compiled from the ACR DIR data and local DRLs established. Scanners with median doses outside the upper/lower DRL were followed-up with. Using effective dose and exam volumes, collective dose was determined before and after protocol adjustments to evaluate the effect of this quality improvement effort. The quality initiative is complete for L-spine and Chest/Abdomen/Pelvis exams and only initial surveys were completed for Head and Abdomen/Pelvis examsg. Median Scanner Dose reductions were 8.8 and 4.9 % for L-spine and Chest/Abdomen/Pelvis exams, respectively, resulting with collective dose reductions of 0.7 and 3.2 person•Sv/yr. Follow-up is ongoing for Abdomen/Pelvis and Head exams.

Serum tocopherol levels in very preterm infants after a single dose of vitamin E at birth.

Science.gov (United States)

Bell, Edward F; Hansen, Nellie I; Brion, Luc P; Ehrenkranz, Richard A; Kennedy, Kathleen A; Walsh, Michele C; Shankaran, Seetha; Acarregui, Michael J; Johnson, Karen J; Hale, Ellen C; Messina, Lynn A; Crawford, Margaret M; Laptook, Abbot R; Goldberg, Ronald N; Van Meurs, Krisa P; Carlo, Waldemar A; Poindexter, Brenda B; Faix, Roger G; Carlton, David P; Watterberg, Kristi L; Ellsbury, Dan L; Das, Abhik; Higgins, Rosemary D

2013-12-01

Our aim was to examine the impact of a single enteral dose of vitamin E on serum tocopherol levels. The study was undertaken to see whether a single dose of vitamin E soon after birth can rapidly increase the low α-tocopherol levels seen in very preterm infants. If so, this intervention could be tested as a means of reducing the risk of intracranial hemorrhage. Ninety-three infants vitamin E or placebo by gastric tube within 4 hours of birth. The vitamin E group received 50 IU/kg of vitamin E as dl-α-tocopheryl acetate (Aquasol E). The placebo group received sterile water. Blood samples were taken for measurement of serum tocopherol levels by high-performance liquid chromatography before dosing and 24 hours and 7 days after dosing. Eighty-eight infants received the study drug and were included in the analyses. The α-tocopherol levels were similar between the groups at baseline but higher in the vitamin E group at 24 hours (median 0.63 mg/dL vs. 0.42 mg/dL, P = .003) and 7 days (2.21 mg/dL vs 1.86 mg/dL, P = .04). There were no differences between groups in γ-tocopherol levels. At 24 hours, 30% of vitamin E infants and 62% of placebo infants had α-tocopherol levels vitamin E raised serum α-tocopherol levels, but to consistently achieve α-tocopherol levels >0.5 mg/dL, a higher dose or several doses of vitamin E may be needed.

Radiation Dose from Voiding Cystourethrography (VCUG) Examination in Children

International Nuclear Information System (INIS)

Siriwiladluk, T.; Krisanachinda, A.

2012-01-01

Introduction: The purpose of this study is to determine entrance skin dose (ESD) from fluoroscopy and radiography procedures in voiding cystourethrography (VCUG) studies of pediatric patients by dose-area product (DAP) recording. Methods: Radiation doses received by 70 patients underwent VCUG procedures were determined by the DAP Meter, Wellh?fer Dosimetrie GmbH, Germany) directly coupled to the x-ray tube window (Philips Omni Diagnost Eleva) and an electrometer connected to a computer for data collection. The study revealed the radiation dose for VCUG and the baseline data on the entrance skin dose, ESD, dose area-product (DAP) and the effective dose, E, to establish local reference dose levels for VCUG in pediatric patients. Results: The mean(minimum-maximum) ESD, DAP and the effective dose of pediatric patients in 4 age ranges were 3.41(1-9) mGy, 46.58 (21.90-158.90) cGycm 2 and 0.10(0.05-0.33) mSv for 0- 1 years, 6.80(2-16) mGy, 115.55 (20.70-258.70)cGycm 2 and 0.24(0.04-0.54) mSv for >1-5 years, 11.76 (3-23) mGy, 292.28 (88.90-593.50)cGycm 2 and 0.61(0.19-1.25) mSv for >5-10 years, and 20.50(10-42) mGy, 575.98(255.60-1247.80) cGycm 2 and 1.12(0.54-2.62) mSv for >10-15 years respectively. Discussion: The dose levels for VCUG as recommended by the national reference doses (NRDs) of UK are classified at patient age of 0-1 years, 90 cGy.cm 2 , >1-5 years, 110 cGy.cm 2 , >5-10 years, 210 cGy.cm 2 and >10-15 years, 470 cGy.cm 2 respectively. Conclusions: The mean DAP of pediatric patients were higher than the dose level as recommended by NRD at the age range >1-5, >5-10 and >10-15 years. The limitation in this study was the non uniform in the number of patients at the higher age. Attempts could be made to lower the radiation dose to avoid the higher risk of developing radiation-induced cancer in children. (author)

Product kerma air area and effective dose in dental radiology; Produto kerma no ar-area e dose efetiva em radiodiagnostico odontologico

Energy Technology Data Exchange (ETDEWEB)

Mauro, Rodrigo A.P.; Souza, M. Daiane M.; Costa, Alessandro M. [Universidade de Sao Paulo (USP), Ribeirao Preto (USP), SP (Brazil). Faculdade de Filosofia Ciencias e Letras

2016-07-01

The main purpose of patient dosimetry in diagnostic radiology is to determine dosimetric quantities for the establishment and use of reference levels and comparative risk assessment. The use of the air kerma-area product, P{sub KA}, has been suggested in dental radiology, as this quantity is more closely related to risk. The aim of this study was to perform a preliminary survey of P{sub KA} and effective dose in different types of dental examinations. The future perspective is a large-scale survey for the establishment and use of diagnostic reference levels in dentistry in Brazil. (author)

Product kerma air area and effective dose in dental radiology; Produto kerma no ar area e dose efetiva em radiodiagnostico odontologico

Energy Technology Data Exchange (ETDEWEB)

Mauro, Rodrigo A.P.; Souza, Daiane M.; Costa, Alessandro M., E-mail: rodrigomauro@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia Ciencias e Letras

2016-07-01

The main purpose of patient dosimetry in diagnostic radiology is to determine dosimetric quantities for the establishment and use of reference levels and comparative risk assessment. The use of the air kerma-area product, P{sub KA}, has been suggested in dental radiology, as this quantity is more closely related to risk. The aim of this study was to perform a preliminary survey of P{sub KA} and effective dose in different types of dental examinations. The future perspective is a large-scale survey for the establishment and use of diagnostic reference levels in dentistry in Brazil. (author)

Survey of doses and frequency of X-ray examinations on children at the intensive care unit of a large reference pediatric hospital

International Nuclear Information System (INIS)

Pedrosa de Azevedo, Ana Cecilia; Osibote, Adelaja Otolorin; Bastos Boechat, Marcia Cristina

2006-01-01

Objective: This work aims to evaluate the entrance surface dose (ESD), the body organ dose (BOD) and the effective dose (E) resulting from pediatric radiological procedures with the use of portable X-ray equipments. Materials and methods: The software DoseCal was used to evaluate the doses imparted to patients. The children were classified according to their weight and age groups, and the study included three sectors of the intensive care unit of a large reference pediatric hospital in Rio de Janeiro. Results: A total of 518 radiographs have been performed (424 for chest and 94 for abdomen). The statistical data were compared with previously published results. The BOD is presented for the most exposed organs. Conclusion: The mean value of ESD and E varied widely among neonates. The highest number of radiographs per infant peaked 33 for chest examination in the age group 0-1 year

Epidemiological surveys on the effects of low-level radiation dose: a comparative assessment. Vol. A: pre-conception irradiation effects. Vol. E (DRAFT A): group collation tables

Energy Technology Data Exchange (ETDEWEB)

Rose, K.S.B.

1988-01-01

In this report, the health effects of low-level doses of radiation are considered by reference to published epidemiological surveys. The work was carried out with three objectives in mind: 1. to provide a comprehensive and critical review of the subject; 2. to seek consistent indications of particular health effects by collating results and comparing with those from surveys at moderate-level doses; 3. to provide an authoritative view on the epidemiology of low-level radiation-induced health effects. Vol E (DRAFT A) is appended and contains group collation tables. Epidemiological surveys can be conveniently divided into four classes (A, B, C, D) according to the phase of life when irradiation occurs or the effect is diagnosed. The first of the classes (A) is addressed here; this class is concerned with possible effects arising from radiation received by a parent before conception. Possible effects of preconception irradiation were identified under four broad groupings. These are Down's syndrome, ''Indicators of Reproductive Damage'' (mainly Primary Sterility, Congenital Abnormalities, Sex Ratio, Fetal Mortality, Infant Mortality), Childhood Malignancies, and Chromosomal Changes in Abortuses. Information about each survey, and comparisons with results from moderate-level dose surveys, are contained in synopses that are set out in the Appendix.

Radiobiological modelling of dose-gradient effects in low dose rate, high dose rate and pulsed brachytherapy

International Nuclear Information System (INIS)

Armpilia, C; Dale, R G; Sandilos, P; Vlachos, L

2006-01-01

This paper presents a generalization of a previously published methodology which quantified the radiobiological consequences of dose-gradient effects in brachytherapy applications. The methodology uses the linear-quadratic (LQ) formulation to identify an equivalent biologically effective dose (BED eq ) which, if applied uniformly to a specified tissue volume, would produce the same net cell survival as that achieved by a given non-uniform brachytherapy application. Multiplying factors (MFs), which enable the equivalent BED for an enclosed volume to be estimated from the BED calculated at the dose reference surface, have been calculated and tabulated for both spherical and cylindrical geometries. The main types of brachytherapy (high dose rate (HDR), low dose rate (LDR) and pulsed (PB)) have been examined for a range of radiobiological parameters/dimensions. Equivalent BEDs are consistently higher than the BEDs calculated at the reference surface by an amount which depends on the treatment prescription (magnitude of the prescribed dose) at the reference point. MFs are closely related to the numerical BED values, irrespective of how the original BED was attained (e.g., via HDR, LDR or PB). Thus, an average MF can be used for a given prescribed BED as it will be largely independent of the assumed radiobiological parameters (radiosensitivity and α/β) and standardized look-up tables may be applicable to all types of brachytherapy treatment. This analysis opens the way to more systematic approaches for correlating physical and biological effects in several types of brachytherapy and for the improved quantitative assessment and ranking of clinical treatments which involve a brachytherapy component

Radiographic image quality and dose at thorax, abdomen and skull of patients at HC-FMB-UNESP

International Nuclear Information System (INIS)

Alvarez, Matheus; Giacomini, Guilherme; Bacchim Neto, Fernando A.; Alves, Allan F.F.; Velo, Alexandre F.; Miranda, Jose R.A.; Pina, Diana R. de

2013-01-01

ICRP 103 specifies reference dose levels to be used during radiographic exams. Usually, the radiographer qualitative determines the best radiographic technique (kV and mAs) in order to obtain better image quality with the lowest dose. The objective of this study was to evaluate the doses used in examination of the chest, abdomen and skull in patients of different physical sizes, and infer about the amount of dose required to maintain acceptable radiological contrast in patients of different physical sizes. Techniques used by experienced radiographers of HC-FMB-UNESP for examinations of the chest (PA), abdomen (AP) and skull (AP) for patients of different thickness (small, medium and thick body) were obtained. Dose measurements were performed referring to all kV/mAs combinations. PMMA phantoms were placed below the ionization chamber. The Signal Difference Noise Ratio (SDNR) of the images of the phantoms were calculated from an area of contrast and a region of normal tissue. The Figure of Merit (FoM) was calculated for each of the exam modality. Measured FoM decreased according to the thickness of the chest and abdomen, indicating the need to increase the dose level to maintain the same level of image contrast. Patients thicker usually end up getting more than twice the dose of lean patients. Required image quality levels for correct diagnosis should be obtained using dose levels as low as reasonably practicable examination. These factors highlight the need for a program of quality assurance and effective dose studies in actual service. (author)

Levels of external natural radiation and doses to population in Heilongjiang province

International Nuclear Information System (INIS)

Liang Yicheng; He Yongjiang; Wang Lu

1985-01-01

The external natural radiation level in Heilongjiang Province was measured by using China-made FD-71 scintillation radiometers and RSS-111 high pressure ionization chambers. The doses of external radiation to population were also calculated. The population-weighted average value of the absorbed dose rate from terrestrial γ-radiation was 7.2 x 10 -8 Gy.h -1 for outdoors, and 10.8 x 10 -8 Gy.h -1 for indoors. The population-weighted average absorbed dose rate in air from cosmic rays was 3.3 x 10 -8 Gy.h -1 . The annual population-weighted average effective dose equivalent and the annual collective effective dose equivalent from the environmental γ-radiation were 620 μSv and 20.1 x 10 3 man.Sv, respectively. The corresponding figures from cosmic rays were 260 μSv and 8.7 x 10 3 man.Sv, respectively

Ambient radioactivity levels and radiation doses. Annual report 2011

International Nuclear Information System (INIS)

Bernhard-Stroel, Claudia; Hachenburger, Claudia; Trugenberger-Schnabel, Angela; Peter, Josef

2013-07-01

The annual report 2011 on ambient radioactivity levels and radiation doses covers the following issues: Part A: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. Part B; Current data and their evaluation: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. The Appendix includes Explanations of terms, radiation doses and related units, external and internal radiation exposure, stochastic and deterministic radiation effects, genetic radiation effects, induction of malignant neoplasm, risk assessment, physical units and glossary, laws, ordinances, guidelines, recommendations and other regulations concerning radiation protection, list of selected radionuclides.

Impact of low-level radiation with special reference to tritium in environment

International Nuclear Information System (INIS)

Bhatia, A.L.

2005-01-01

Radiation is invisible, but exists in various types, in the form of particles and/or energy bundles. The effects of low-level radiation seem very abstract since these can not be perceived by our sensory organs. The increase in natural background radiation from various inadvertent sources like tritium has the prospect of altering the entire scenario of billions of years' slow and steady biogenetic evolution. Mankind, by developing atomic technologies, is unleashing forces which it does understand but not beyond experimental findings. There is no wise sorcerer who can undo the damage we are causing. Tritium is a radioactive form of hydrogen that is produced in the reactor core. The released tritium replaces hydrogen in water. Tritium in water when gets ingested, causes continuos internal low-level beta radiation exposure over a long period. Proposed presentation will focus on the possible long term damage caused by its low-level exposure is dependent on the length of duration living tissue spends in the radiation field, not on the relative radiation field strength. As internal radiation pulses never stop, impact is continuous by the ambient radiation atmosphere. There is no chance to heal at the molecular level, except small chances of DNA repair since the organically bound tritium has greater severe influence with the slow turnover. Though the situation needs not be alarming with tritium, the studies on radiation damage on various parameters have given evidence of two compartments of radiation damage; the reparable or potentially lethal and the irreparable or lethal. With emerging new reports on the stochastic effects, those for which the probability, rather than the severity of an effect from tritium occurring as a function of dose also can not be ruled out. Biotoxicity of tritium in the form of induction of cancer, hereditary effects, teratogenesis and life shortening really needs an exhaustive investigation and warrants careful evaluation. However, a positive

Analysis of the personal doses lower than the reporting level

International Nuclear Information System (INIS)

Askounis, P.; Papadomarkaki, E.; Kirgiakou, H.; Dimitropoulou, F.; Carinou, E.; Maltezos, A.; Kamenopoulou, V.

2008-01-01

The personnel dosimetry department of Greek Atomic Energy Commission (GAEC) is the only laboratory in the country that assures the individual monitoring of more than 10,500 workers with whole body dosemeters and 100 workers with extremity dosemeters at 1300 establishments. Every year a statistical analysis of the results is performed that provides data for epidemiological studies and assists the evaluation of the radiation protection system of the country. The aim of this study is to perform an analysis of the doses that are lower than the reporting level. The vast majority (92%) of the evaluated H p (10) doses has been reported and recorded as zero. The mean H p (10) (of the non-reported doses) per dosemeter and per monitoring period has been calculated for every geographical department of Greece. The results were compared with the ones produced by the external gamma rate measurements performed by GAEC's telemetric network. The conclusion that can be drawn is that the part of the TL signal of the personal dosemeters is due to the natural background radiation and this can affect the evaluation of the low doses

Entrance surface dose measurements in pediatric radiological examinations

International Nuclear Information System (INIS)

Ribeiro, L.A.; Yoshimura, E.M.

2008-01-01

A survey of pediatric radiological examinations was carried out in a reference pediatric hospital of the city of Sao Paulo, in order to investigate the doses to children undergoing conventional X-ray examinations. The results showed that the majority of pediatric patients are below 4 years, and that about 80% of the examinations correspond to chest projections. Doses to typical radiological examinations were measured in vivo with thermoluminescent dosimeters (LiF: Mg, Ti and LiF: Mg, Cu, P) attached to the skin of the children to determine entrance surface dose (ESD). Also homogeneous phantoms were used to obtain ESD to younger children, because the technique uses a so small kVp that the dosimeters would produce an artifact image in the patient radiograph. Four kinds of pediatric examinations were investigated: three conventional examinations (chest, skull and abdomen) and a fluoroscopic procedure (barium swallow). Relevant information about kVp and mAs values used in the examinations was collected, and we discuss how these parameters can affect the ESD. The ESD values measured in this work are compared to reference levels published by the European Commission for pediatric patients. The results obtained (third-quartile of the ESD distribution) for chest AP examinations in three age groups were: 0.056 mGy (2-4 years old); 0.068 mGy (5-9 years old); 0.069 mGy (10-15 years old). All of them are below the European reference level (0.100 mGy). ESD values measured to the older age group in skull and abdomen AP radiographs (mean values 3.44 and 1.20 mGy, respectively) are above the European reference levels (1.5 mGy to skull and 1.0 mGy to abdomen). ESD values measured in the barium swallow examination reached 10 mGy in skin regions corresponding to thyroid and esophagus. It was noticed during this survey that some technicians use, improperly, X-ray fluoroscopy in conventional examinations to help them in positioning the patient. The results presented here are a

Assessment of 226Ra age-dependent dose from water intake

International Nuclear Information System (INIS)

Porntepkasemsan, Boonsom; Srisuksawad, Kanitha

2008-01-01

The radioactivity in canal and ground waters collected in a 2-year long observation from the vicinity of the Rare Earth Research and Development Center (RRDC), Phathumthani Province, Thailand, was measured in order to determine the concentration of 226 Ra and to estimate the age-dependent effective dose to humans due to consumption. 226 Ra activities in both canal and ground waters were well below the WHO guidance level for drinking water quality of 1 Bq L -1 . The highest 226 Ra effective doses per year were found for infants and teens. However, the observed levels of calculated 226 Ra effective doses for all age groups in both canal and ground waters show satisfactory low values (less than 15 μSv yr -1 ). These values are acceptable in accordance with the WHO recommended reference dose level of 100 μSv yr -1 from water intake of 2 L day -1

Dose and dose commitment calculations from groundwaterborne radio-active elements released from a repository for spent nuclear fuel

International Nuclear Information System (INIS)

Bergstroem, U.

1983-05-01

The turnover of radioactive matter entering the biosphere with groundwater has been studied with regard to exposure and doses to critical groups and populations. Two main recipients, a well and a lake, have been considered for the inflow of groundwaterborne nuclides. Mathematical models of a set of coupled ecosystems on regional, intermediate and global levels have been used for calculations of doses. The intermediate system refers to the Baltic Sea. The mathematical treatment of the model is based upon compartment theory with first order kinetics and also includes products in decay chains. The time-dependent exposures have been studied for certain long-lived nuclides of radiological interest in waste from disposed fuel. Dose and dose commitment have been calculated for different episodes for inflow to the biosphere. (author)

Cumulative effective and individual organ dose levels in paediatric patients undergoing multiple catheterizations for congenital heart disease

International Nuclear Information System (INIS)

Jones, T.P.; Brennan, P.C.; Ryan, E.

2017-01-01

This study examines the cumulative radiation dose levels received by a group of children who underwent multiple cardiac catheterisation procedures during the investigation and management of congenital heart disease (CHD). The purpose is to calculate cumulative doses, identify higher dose individuals, outline the inconsistencies with risk assessment and encourage the establishment of dose databases in order to facilitate the longitudinal research necessary to better understand health risks. A retrospective review of patient records for 117 paediatric patients who have undergone two or more cardiac catheterizations for the investigation of CHD was undertaken. This cohort consisted of patients who were catheterised over a period from September 2002 to August 2014. The age distribution was from newborn to 17 y. Archived kerma-area product (P KA ) and fluoroscopy time (T) readings were retrieved and analysed. Cumulative effective and individual organ doses were determined. The cumulative P KA levels ranged from 1.8 to 651.2 Gycm 2 , whilst cumulative effective dose levels varied from 2 to 259 mSv. The cumulative fluoroscopy time was shown to vary from 8.1 to 193.5 min. Median cumulative organ doses ranged from 3 to 94 mGy. Cumulative effective dose levels are highly variable but may exceed 250 mSv. Individual organ and effective dose measurements remain useful for comparison purposes between institutions although current methodologies used for determining lifetime risks are inadequate. (authors)

Product kerma in the air-area and radiation dose in dental radiodiagnosis; Produto kerma ar-area e dose efetiva em radiodiagnostico odontologico

Energy Technology Data Exchange (ETDEWEB)

Costa, Alessandro Martins da, E-mail: amcosta@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica

2014-07-01

The main purpose of patient dosimetry in diagnostic radiology is to determine dosimetric quantities for the establishment and use of reference levels and comparative risk assessment. In recent publications the use of the air kerma-area product, PKA, has been suggested in dental radiology, as this quantity is more closely related to risk. The aim of this study was to perform a preliminary survey of PKA and effective dose in different types of dental examinations. The future perspective is a large-scale survey for the establishment and use of diagnostic reference levels in dentistry in Brazil. (author)

Dose to patients and professionals in cardiology interventional: Progress of multicenter group Doccaci

International Nuclear Information System (INIS)

Sanchez, R. M.; Vano, E.; Fernandez, J. M.; Goicolea Ruigomez, J.; Pifarre, X.; Escaned, J.; Rovira, J. J.; Garcia del Blanco, B.; Carrera, F.; Diaz, J. F.; Ordiales, J. M.; Nogales, J. M.; Hernandez, J.; Bosa, F.; Rosales, F.; Saez, J. R.; Soler, M. M.; Romero, M. A.

2013-01-01

The multidisciplinary group and multicenter DOCCACI (dosimetry and quality assurance in interventional cardiology), sponsored by the section of haemodynamics of the Spanish society of Cardiology, is intended to propose reference levels to doses received by patients in interventional cardiology procedures such as recommended by the International Commission on radiological protection It also investigates the doses received by professionals, in particular dose in Crystallyne whose recommended limit dose has been reduced recently from 150 to 20 mSv/year. (Author)

Survey of computed tomography doses in head and chest protocols; Levantamento de doses em tomografia computadorizada em protocolos de cranio e torax

Energy Technology Data Exchange (ETDEWEB)

Souza, Giordana Salvi de; Silva, Ana Maria Marques da, E-mail: giordana.souza@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Fisica. Nucleo de Pesquisa em Imagens Medicas

2016-07-01

Computed tomography is a clinical tool for the diagnosis of patients. However, the patient is subjected to a complex dose distribution. The aim of this study was to survey dose indicators in head and chest protocols CT scans, in terms of Dose-Length Product(DLP) and effective dose for adult and pediatric patients, comparing them with diagnostic reference levels in the literature. Patients were divided into age groups and the following image acquisition parameters were collected: age, kV, mAs, Volumetric Computed Tomography Dose Index (CTDIvol) and DLP. The effective dose was found multiplying DLP by correction factors. The results were obtained from the third quartile and showed the importance of determining kV and mAs values for each patient depending on the studied region, age and thickness. (author)

Pilot-benchmarking of the WENRA safety reference levels for the spent fuel intermediate storage facility Ahaus

International Nuclear Information System (INIS)

Lorenz, Bernd; Roeder, Markus; Brandt, Klaus-Dieter

2008-01-01

Full text: The Western European Nuclear Regulator's Association (WENRA) has 2007 issued the draft of the 'Waste and Spent Fuel Storage Safety Reference Levels'. The objective of WENRA is to strive for a harmonized safety level of nuclear facilities within the European Community and these Reference Levels are a benchmark method to demonstrate the achieved level for the regulatory system and the implementation as well. Safety Reference Levels exist at the moment for Reactor Safety, Waste Storage and Decommissioning in different stages of development. ENISS, the European Nuclear Installations Safety Standards Initiative, a FORATOM based special organisation of nuclear operators, has discussed these Safety Reference Levels very intensively with WENRA and the agreement was to make a implementation benchmark-exercise for the storage facilities before the authorities finally agree on the Reference Levels. This benchmark was scheduled for the year 2008. Because of the special situation in Germany where a large number of storage facilities is in operation the German authorities felt that it would be useful to initiate a Pilot-Benchmark to get first results on the feasibility of the Reference Levels and the burden imposed to authorities and operators by these benchmark-exercises. GNS, a subsidiary company of the utilities, agreed to step into this process on a voluntary basis with its storage facility for spent fuel in Ahaus. The exercise was done in a very efficient way and in good co-operation between the authorities, local and federal, and the operator. The results in terms of safety assessments have been very satisfactory showing the high degree of safety. Although the facility was for the first time licensed already in 1987 the compliance with nearly all Reference Levels from 2007 could be demonstrated. It became also clear that newer facilities would fulfil the desired safety standard too. Nevertheless, in spite of the good results the exercise revealed some weak

Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography

International Nuclear Information System (INIS)

Yang, Lin; Liang, Changhong; Zhuang, Jian; Huang, Meiping; Liu, Hui

2017-01-01

Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level. We optimized the iteration level of iDose"4 and evaluated image quality for pediatric cardiac CT angiography. Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose"4 levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose"4-optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test. Mean scores for iDose"4 level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose"4 level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference). iDose"4 level 4 was optimal for both the full- and half-dose groups. Protocols with iDose"4 level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy. (orig.)

Diagnostic reference levels in intraoral radiology: From the laboratory to clinical practice

International Nuclear Information System (INIS)

Alcaraz, M.; Velasco, E.; Martinez-Beneyto, Y.; Velasco, F.; Parra, C.; Canteras, M.

2010-01-01

To determine the diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice and to explain the differences between the levels found and the DRLs obtained in other experimental conditions, suggesting that there has been a reduction in the European Union (EU) recommended levels. A total of 2296 official reports on dental surgeries from 16 Spanish autonomous regions compiled during 2008 were studied. A mean DRL of 3.3 mGy was determined: 2.6 mGy for installations using direct digital systems, 3.4 mGy for those using indirect systems, 4.4 mGy for those using Ultra-speed film and 3.7 mGy for those using Insight. The DRLs found in this survey are below the EU recommended values but far above previously described values, possibly because all the different systems were considered and because values refer to those of the normal work conditions of clinical practice. (authors)

Radiation doses from computed tomography practice in Johor Bahru, Malaysia

International Nuclear Information System (INIS)

Karim, M.K.A.; Hashim, S.; Bradley, D.A; Bakar, K.A.; Haron, M.R.; Kayun, Z.

2016-01-01

Radiation doses for Computed Tomography (CT) procedures have been reported, encompassing a total of 376 CT examinations conducted in one oncology centre (Hospital Sultan Ismail) and three diagnostic imaging departments (Hospital Sultanah Aminah, Hospital Permai and Hospital Sultan Ismail) at Johor hospital's. In each case, dose evaluations were supported by data from patient questionnaires. Each CT examination and radiation doses were verified using the CT EXPO (Ver. 2.3.1, Germany) simulation software. Results are presented in terms of the weighted computed tomography dose index (CTDI w ), dose length product (DLP) and effective dose (E). The mean values of CTDI w , DLP and E were ranged between 7.6±0.1 to 64.8±16.5 mGy, 170.2±79.2 to 943.3±202.3 mGy cm and 1.6±0.7 to 11.2±6.5 mSv, respectively. Optimization techniques in CT are suggested to remain necessary, with well-trained radiology personnel remaining at the forefront of such efforts. - Highlights: • We investigate radiation doses received by patients from CT scan examinations. • We compare data with current national diagnostic reference levels and other references. • Radiation doses from CT were influenced by CT parameter, scanning techniques and patient characteristics.

Patient radiation dose audits for fluoroscopically guided interventional procedures

International Nuclear Information System (INIS)

Balter, Stephen; Rosenstein, Marvin; Miller, Donald L.; Schueler, Beth; Spelic, David

2011-01-01

Purpose: Quality management for any use of medical x-ray imaging should include monitoring of radiation dose. Fluoroscopically guided interventional (FGI) procedures are inherently clinically variable and have the potential for inducing deterministic injuries in patients. The use of a conventional diagnostic reference level is not appropriate for FGI procedures. A similar but more detailed quality process for management of radiation dose in FGI procedures is described. Methods: A method that takes into account both the inherent variability of FGI procedures and the risk of deterministic injuries from these procedures is suggested. The substantial radiation dose level (SRDL) is an absolute action level (with regard to patient follow-up) below which skin injury is highly unlikely and above which skin injury is possible. The quality process for FGI procedures collects data from all instances of a given procedure from a number of facilities into an advisory data set (ADS). An individual facility collects a facility data set (FDS) comprised of all instances of the same procedure at that facility. The individual FDS is then compared to the multifacility ADS with regard to the overall shape of the dose distributions and the percent of instances in both the ADS and the FDS that exceed the SRDL. Results: Samples of an ADS and FDS for percutaneous coronary intervention, using the dose metric of reference air kerma (K a,r ) (i.e., the cumulative air kerma at the reference point), are used to illustrate the proposed quality process for FGI procedures. Investigation is warranted whenever the FDS is noticeably different from the ADS for the specific FGI procedure and particularly in two circumstances: (1) When the facility's local median K a,r exceeds the 75th percentile of the ADS and (2) when the percent of instances where K a,r exceeds the facility-selected SRDL is greater for the FDS than for the ADS. Conclusions: Analysis of the two data sets (ADS and FDS) and of the

Issues raised by the reference doses for perfluorooctane sulfonate and perfluorooctanoic acid.

Science.gov (United States)

Dong, Zhaomin; Bahar, Md Mezbaul; Jit, Joytishna; Kennedy, Bruce; Priestly, Brian; Ng, Jack; Lamb, Dane; Liu, Yanju; Duan, Luchun; Naidu, Ravi

2017-08-01

On 25th May 2016, the U.S. EPA released reference doses (RfDs) for Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) of 20ng/kg/day, which were much more conservative than previous values. These RfDs rely on the choices of animal point of departure (PoD) and the toxicokinetics (TK) model. At this stage, considering that the human evidence is not strong enough for RfD determination, using animal data may be appropriate but with more uncertainties. In this article, the uncertainties concerning RfDs from the choices of PoD and TK models are addressed. Firstly, the candidate PoDs should include more critical endpoints (such as immunotoxicity), which may lead to lower RfDs. Secondly, the reliability of the adopted three-compartment TK model is compromised: the parameters are not non-biologically plausible; and this TK model was applied to simulate gestation and lactation exposures, while the two exposure scenarios were not actually included in the model structure. Copyright © 2017. Published by Elsevier Ltd.

Analysis of data relative to the update of diagnostic reference levels in radiology and nuclear medicine. 2011-2012 review

International Nuclear Information System (INIS)

2014-01-01

Applying the Order of 24 October 2011 on diagnostic reference levels, departments of radiology and nuclear medicine must send a sample of 'patient' dosimetric data to the IRSN each year. The results of the analysis of dosimetric data performed between the 1 January 2011 and the 31 December 2012 presented in this report should enable the authority to define the needs for updating regulations. Professional involvement in DRLs improved globally over the 2011-2012 period but is heterogeneous according to the imaging area considered. The participation of conventional radiology professionals is still low, with less than 30% against over 75% in CT and 85% in nuclear medicine. Data collection in pediatrics, considering all the fields of medical imaging, remains extremely limited. This shows almost no dose assessment for children by imaging departments, and has the effect of not allowing authorities to provide professionals with DRLs representative of pediatric practices. The analysis of radiology doses and nuclear medicine administered activities by IRSN shows an overall decrease of statistical indicators on which DRLs are indexed. These results lead to proposals for updating reference values for a large number of examinations. In addition to the analysis of data collected for examinations currently mentioned in regulatory texts, IRSN recommends to update DRLs in a more general way by changing the strategy for collecting and updating pediatric DRLs, by including interventional radiology - specialty in which the radiation protection presents a major challenge - by introducing a more ambitious indicator than the 75. percentile in conventional radiology and nuclear medicine - the 25. percentile statistical indicator, and by taking into account new technologies inducing additional exposures to the patient as CT-scan associated with the PET. (authors)

Dose survey of pediatric and adult patients in Sudan

International Nuclear Information System (INIS)

Mohamadain, K.E.M.; Azevedo, A.C.P.; And others

2006-01-01

A survey of radiation doses to children and adults from diagnostic radiography has been carried out in seven hospitals in Sudan. In four hospitals only pediatric examinations were died. In two hospitals only adult patients were recorded and in one hospital both kinds of patients (pediatric and adults) were evaluated. For pediatric patients only chest x-ray examination was evaluated and children were divided according to age ranges: from (0-1) and 5) years for chest AP only and from (5-10) and (10-15) for chest PA. For adult patients the examinations were chest AP and PA, abdomen AP and skull AP and PA. Entrance Surface Dose SD) and the Effective Dose (E) were calculated using the Dose Cal software. The mean ESD r children, measured in p.Gy, ranged from (45-53) and (53-56) for (0-1) and (1-5) years, respectively and from (55-71) and (68-85) for (5-10) and (10-15) years, respectively. In two of le pediatric hospitals the mean ESD values were greater than the CEC Reference Dose Levels. In El bulk and Si nar hospitals the values ranged from 167-261 and 186-308 μGy for the age ranges (0-1) and (1-5) respectively and 167-194 and 279-312 μGy for the age ranges of (5-10) and (10-15) respectively. For adult patients the ESD and E dose values evaluated in Alfisal hospital presented values comparable with the CEC Reference Dose Level. However for Alshorta hospital the values were higher for the chest AP and PA with results for ESD 0.446 and 0.551 mGy respectively

Radiation doses and possible radiation effects of low-level, chronic radiation in vegetation

International Nuclear Information System (INIS)

Rhoads, W.A.; Franks, L.A.

1975-01-01

Measurements were made of radiation doses in soil and vegetation in Pu-contaminated areas at the Nevada Test Site with the objective of investigating low-level, low-energy gamma radiation (with some beta radiation) effects at the cytological or morphological level in native shrubs. In this preliminary investigation, the exposure doses to shrubs at the approximate height of stem apical meristems were estimated from 35 to 140 R for a ten-year period. The gamma exposure dose estimated for the same period was 20.7 percent +- 6.4 percent of that recorded by the dosimeters used in several kinds of field instrument surveys. Hence, a survey instrument reading made at about 25 cm in the tops of shrubs should indicate about 1 / 5 the dosimeter-measured exposures. No cytology has yet been undertaken because of the drought since last winter. (auth)

Radiation doses in alternative commercial high-level waste management systems

International Nuclear Information System (INIS)

Schneider, K.J.; Pelto, P.J.; Lavender, J.C.; Daling, P.M.; Fecht, B.A.

1986-01-01

In the commercial high-level waste management system, potential changes are being considered that will augment the benefits of an integral monitored retrievable storage (MRS) facility. The US Department of Energy (DOE) has recognized that alternative options could be implemented in the authorized waste management system (i.e., without an integral MRS facility) to potentially achieve some of the same beneficial effects of the integral MRS system. This paper summarizes those DOE-sponsored analyses related to radiation doses resulting from changes in the waste management system. This report presents generic analyses of aggregated radiation dose impacts to the public and occupational workers, of nine postulated changes in the operation of a spent-fuel management system without an MRS facility

Monitoring of doses to patients in interventional cardiology: first results from three Serbian hospitals

International Nuclear Information System (INIS)

Ciraj-Bjelac, Olivera; Arandjic, Danijela; Kosutic, Dushko

2010-01-01

The aim of this work is to assess level of radiation dose to patients in interventional cardiology procedures in three large Serbian hospitals and to investigate possibility for setting of trigger levels if dose quantities exceed certain levels. Three dedicated interventional cardiology laboratories were included in the survey. Information on annual workload was estimated based on number of coronary angiography (CA) procedures and percutaneous coronary interventions (PCI). Patients doses were assessed in terms of air kerma area product (PKA) and air kerma in international reference point (KIRP). Results were compared with internationally proposed Diagnostic Reference Levels (DRL) and similar surveys results. Average total annual number of procedures was 820, 1100 and 2500 in three hospitals, respectively, while total number of dose measurements was 337. All three centers reported PKA values higher than 100 Gy·cm 2 and even values above 200 Gy·cm 2 , corresponding to 42% and 16% of all measurements. Measured KIRP value higher than 5 Gy was reported in one center, indicating that skin doses associated possibility of skin injuries were observed. PKA mean hospital values for CA ranged from 33 to 78 Gy·cm 2 and for PCI from 73 to 113 Gy·cm 2 , while associated vales for KIRP were: 0.45-1.2 Gy and 1.1-1.8 Gy, respectively. Comparison of obtained results with international DRL indicated that significant number of procedures is not optimally performed as in some centers more than a half of patients receive doses above DRL. The presented results are valuable input for dose optimization strategies and increased awareness related to importance of dose management. With respect to high dose values, risk for stochastic effects and tissue reactions, dose management methods were proposed. (Author)