Developing a flexible and verifiable integrated dose assessment capability

International Nuclear Information System (INIS)

Parzyck, D.C.; Rhea, T.A.; Copenhaver, E.D.; Bogard, J.S.

1987-01-01

A flexible yet verifiable system of computing and recording personnel doses is needed. Recent directions in statutes establish the trend of combining internal and external doses. We are developing a Health Physics Information Management System (HPIMS) that will centralize dosimetry calculations and data storage; integrate health physics records with other health-related disciplines, such as industrial hygiene, medicine, and safety; provide a more auditable system with published algorithms and clearly defined flowcharts of system operation; readily facilitate future changes dictated by new regulations, new dosimetric models, and new systems of units; and address ad-hoc inquiries regarding worker/workplace interactions, including potential synergisms with non-radiation exposures. The system is modular and provides a high degree of isolation from low-level detail, allowing flexibility for changes without adversely affecting other parts of the system. 10 refs., 3 figs

Independent dose calculation in IMRT for the Tps Iplan using the Clarkson modified integral

International Nuclear Information System (INIS)

Adrada, A.; Tello, Z.; Garrigo, E.; Venencia, D.

2014-08-01

Intensity-Modulated Radiation Therapy (IMRT) treatments require a quality assurance (Q A) specific patient before delivery. These controls include the experimental verification in dose phantom of the total plan as well as dose distributions. The use of independent dose calculation (IDC) is used in 3D-Crt treatments; however its application in IMRT requires the implementation of an algorithm that allows considering a non-uniform intensity beam. The purpose of this work was to develop IDC software in IMRT with MLC using the algorithm proposed by Kung (Kung et al. 2000). The software was done using Matlab programming. The Clarkson modified integral was implemented on each flowing, applying concentric rings for the dose determination. From the integral of each field was calculated the dose anywhere. One time finished a planning; all data are exported to a phantom where a Q A plan is generated. On this is calculated the half dose in a representative volume of the ionization chamber and the dose at the center of it. Until now 230 IMRT planning were analyzed carried out ??in the treatment planning system (Tps) Iplan. For each one of them Q A plan was generated, were calculated and compared calculated dose with the Tps, IDC system and measurement with ionization chamber. The average difference between measured and calculated dose with the IDC system was 0.4% ± 2.2% [-6.8%, 6.4%]. The difference between the measured and the calculated doses by the pencil-beam algorithm (Pb) of Tps was 2.6% ± 1.41% [-2.0%, 5.6%] and with the Monte Carlo algorithm was 0.4% ± 1.5% [-4.9%, 3.7%]. The differences of the carried out software are comparable to the obtained with the ionization chamber and Tps in Monte Carlo mode. (author)

Step-and-Shoot versus Compensator-based IMRT: Calculation and Comparison of Integral Dose in Non-tumoral and Target Organs in Prostate Cancer

Directory of Open Access Journals (Sweden)

Kaveh Shirani Tak Abi

2015-05-01

Full Text Available Introduction Intensity-Modulated Radiotherapy (IMRT is becoming an increasingly routine treatment method. IMRT can be delivered by use of conventional Multileaf Collimators (MLCs and/or physical compensators. One of the most important factors in selecting an appropriate IMRT technique is integral dose. Integral dose is equal to the mean energy deposited in the total irradiated volume of the patient. The aim of the present study was to calculate and compare the integral dose in normal and target organs in two different procedures of IMRT: Step-and-Shoot (SAS and compensator-based IMRT. Materials and Methods In this comparative study, five patients with prostate cancer were selected. Module Integrated Radiotherapy System was applied, using three energy ranges. In both treatment planning methods, the integral dose dramatically decreased by increasing energy. Results Comparison of two treatment methods showed that on average, the integral dose of body in SAS radiation therapy was about 1.62% lower than that reported in compensator-based IMRT. In planning target volume, rectum, bladder, and left and right femoral heads, the integral doses for SAS method were 1.01%, 1.02%, 1.11%, 1.47%, and 1.40% lower than compensator-based IMRT, respectively. Conclusion Considering the treatment conditions, the definition of dose volume constraints for healthy tissues, and the equal volume of organs in both treatment methods, SAS radiation therapy by providing a lower integral dose seems to be more advantageous and efficient for prostate cancer treatment, compared to compensator-based IMRT.

A hybrid electron and photon IMRT planning technique that lowers normal tissue integral patient dose using standard hardware.

Science.gov (United States)

Rosca, Florin

2012-06-01

To present a mixed electron and photon IMRT planning technique using electron beams with an energy range of 6-22 MeV and standard hardware that minimizes integral dose to patients for targets as deep as 7.5 cm. Ten brain cases, two lung, a thyroid, an abdominal, and a parotid case were planned using two planning techniques: a photon-only IMRT (IMRT) versus a mixed modality treatment (E+IMRT) that includes an enface electron beam and a photon IMRT portion that ensures a uniform target coverage. The electron beam is delivered using a regular cutout placed in an electron cone. The electron energy was chosen to provide a good trade-off between minimizing integral dose and generating a uniform, deliverable plan. The authors choose electron energies that cover the deepest part of PTV with the 65%-70% isodose line. The normal tissue integral dose, the dose for ring structures around the PTV, and the volumes of the 75%, 50%, and 25% isosurfaces were used to compare the dose distributions generated by the two planning techniques. The normal tissue integral dose was lowered by about 20% by the E+IMRT plans compared to the photon-only IMRT ones for most studied cases. With the exception of lungs, the dose reduction associated to the E+IMRT plans was more pronounced further away from the target. The average dose ratio delivered to the 0-2 cm and the 2-4 cm ring structures for brain patients for the two planning techniques were 89.6% and 70.8%, respectively. The enhanced dose sparing away from the target for the brain patients can also be observed in the ratio of the 75%, 50%, and 25% isodose line volumes for the two techniques, which decreases from 85.5% to 72.6% and further to 65.1%, respectively. For lungs, the lateral electron beams used in the E+IMRT plans were perpendicular to the mostly anterior/posterior photon beams, generating much more conformal plans. The authors proved that even using the existing electron delivery hardware, a mixed electron/photon planning

Optimization of total arc degree for stereotactic radiotherapy by using integral biologically effective dose and irradiated volume

International Nuclear Information System (INIS)

Lim, Do Hoon; Kim, Dae Yong; Lee, Myung Za; Chun, Ha Chung

2001-01-01

To find the optimal values of total arc degree to protect the normal brain tissue from high dose radiation in stereotactic radiotherapy planning. With Xknife-3 planning system and 4 MV linear accelerator, the authors planned under various values of parameters. One isocenter, 12, 20, 30, 40, 50, and 60 mm of collimator diameters, 100 deg, 200 deg, 300 deg, 400 deg, 500 deg, 600 deg, of total arc degrees, and 30 deg or 45 deg of arc intervals were used. After the completion of planning, the plans were compared each other using V 50 (the volume of normal brain that is delivered high dose radiation) and integral biologically effective dose. At 30 deg of arc interval, the values of V 50 had the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 deg arc interval, up to 400 deg of total arc degree, the values of V 50 decreased with the increase of total arc degree, but at 500 deg and 600 deg of total arc degrees, the values increased. At 30 deg of arc interval, integral biologically effective dose showed the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 deg arc interval with less than 40 mm collimator diameter, the integral biologically effective dose decreased with the increase of total arc degree, but with 50 and 60 mm of collimator diameters, up to 400 deg of total arc degree, integral biologically effective dose decreased with the increase of total arc degree, but at 500 deg and 600 deg of total arc degrees, the values increased. In the stereotactic radiotherapy planning for brain lesions, planning with 400 deg of total arc degree is optimal. Especially, when the larger collimator more than 50 mm diameter should be used, the uses of 500 deg and 600 deg of total arc degrees make the increase of V 50 and integral biologically effective dose, Therefore stereotactic radiotherapy planning using 400 deg of total arc degree can increase the therapeutic ratio and produce the effective outcome

Dose calculations for irregular fields using three-dimensional first-scatter integration

International Nuclear Information System (INIS)

Boesecke, R.; Scharfenberg, H.; Schlegel, W.; Hartmann, G.H.

1986-01-01

This paper describes a method of dose calculations for irregular fields which requires only the mean energy of the incident photons, the geometrical properties of the irregular field and of the therapy unit, and the attenuation coefficient of tissue. The method goes back to an approach including spatial aspects of photon scattering for inhomogeneities for the calculation of dose reduction factors as proposed by Sontag and Cunningham (1978). It is based on the separation of dose into a primary component and a scattered component. The scattered component can generally be calculated for each field by integration over dose contributions from scattering in neighbouring volume elements. The quotient of this scattering contribution in the irregular field and the scattering contribution in the equivalent open field is then the correction factor for scattering in an irregular field. A correction factor for the primary component can be calculated if the attenuation of the photons in the shielding block is properly taken into account. The correction factor is simply given by the quotient of primary photons of the irregular field and the primary photons of the open field. (author)

Insulator photocurrents: Application to dose rate hardening of CMOS/SOI integrated circuits

International Nuclear Information System (INIS)

Dupont-Nivet, E.; Coiec, Y.M.; Flament, O.; Tinel, F.

1998-01-01

Irradiation of insulators with a pulse of high energy x-rays can induce photocurrents in the interconnections of integrated circuits. The authors present, here, a new method to measure and analyze this effect together with a simple model. They also demonstrate that these insulator photocurrents have to be taken into account to obtain high levels of dose-rate hardness with CMOS on SOI integrated circuits, especially flip-flops or memory blocks of ASICs. They show that it explains some of the upsets observed in a SRAM embedded in an ASIC

Comparison of IMRT Treatment Plans Between Linac and Helical Tomotherapy Based on Integral Dose and Inhomogeneity Index

International Nuclear Information System (INIS)

Shi Chengyu; Penagaricano, Jose; Papanikolaou, Niko

2008-01-01

Intensity modulated radiotherapy (IMRT) is an advanced treatment technology for radiation therapy. There are several treatment planning systems (TPS) that can generate IMRT plans. These plans may show different inhomogeneity indices to the planning target volume (PTV) and integral dose to organs at risk (OAR). In this study, we compared clinical cases covering different anatomical treatment sites, including head and neck, brain, lung, prostate, pelvis, and cranio-spinal axis. Two treatment plans were developed for each case using Pinnacle 3 and helical tomotherapy (HT) TPS. The inhomogeneity index of the PTV and the non-tumor integral dose (NTID) were calculated and compared for each case. Despite the difference in the number of effective beams, in several cases, NTID did not increase from HT as compared to the step-and-shoot delivery method. Six helical tomotherapy treatment plans for different treatment sites have been analyzed and compared against corresponding step-and-shoot plans generated with the Pinnacle 3 planning system. Results show that HT may produce plans with smaller integral doses to healthy organs, and fairly homogeneous doses to the target as compared to linac-based step-and-shoot IMRT planning in special treatment site such as cranio-spinal

Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy

Directory of Open Access Journals (Sweden)

Stefano G. Masciullo

2012-11-01

Full Text Available The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID in stereotactic body radiation therapy (SBRT with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT, estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10Gy for tumor tissue and imposing the same biological effective dose (BED on the target (BED = 76Gy10. Total NTIDs for both techniques was calculated considering α/β = 3Gy for healthy tissue. Excess absolute cancer risk (EAR was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05. Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002, secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001. This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged.

Measurements of integrated components' parameters versus irradiation doses gamma radiation (60Co) dosimetry-methodology-tests

International Nuclear Information System (INIS)

Fuan, J.

1991-01-01

This paper describes the methodology used for the irradiation of the integrated components and the measurements of their parameters, using Quality Insurance of dosimetry: - Measurement of the integrated dose using the competences of the Laboratoire Central des Industries Electriques (LCIE): - Measurement of irradiation dose versus source/component distance, using a calibrated equipment. - Use of ALANINE dosimeters, placed on the support of the irradiated components. - Assembly and polarization of components during the irradiations. Selection of the irradiator. - Measurement of the irradiated components's parameters, using the competences of the societies: - GenRad: GR130 tests equipement placed in the DEIN/SIR-CEN SACLAY. - Laboratoire Central des Industries Electriques (LCIE): GR125 tests equipment and this associated programmes test [fr

Total Dose Effects on Bipolar Integrated Circuits at Low Temperature

Science.gov (United States)

Johnston, A. H.; Swimm, R. T.; Thorbourn, D. O.

2012-01-01

Total dose damage in bipolar integrated circuits is investigated at low temperature, along with the temperature dependence of the electrical parameters of internal transistors. Bandgap narrowing causes the gain of npn transistors to decrease far more at low temperature compared to pnp transistors, due to the large difference in emitter doping concentration. When irradiations are done at temperatures of -140 deg C, no damage occurs until devices are warmed to temperatures above -50 deg C. After warm-up, subsequent cooling shows that damage is then present at low temperature. This can be explained by the very strong temperature dependence of dispersive transport in the continuous-time-random-walk model for hole transport. For linear integrated circuits, low temperature operation is affected by the strong temperature dependence of npn transistors along with the higher sensitivity of lateral and substrate pnp transistors to radiation damage.

Intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high-grade gliomas: Does IMRT increase the integral dose to normal brain?

International Nuclear Information System (INIS)

Hermanto, Ulrich; Frija, Erik K.; Lii, MingFwu J.; Chang, Eric L.; Mahajan, Anita; Woo, Shiao Y.

2007-01-01

Purpose: To determine whether intensity-modulated radiotherapy (IMRT) treatment increases the total integral dose of nontarget tissue relative to the conventional three-dimensional conformal radiotherapy (3D-CRT) technique for high-grade gliomas. Methods and Materials: Twenty patients treated with 3D-CRT for glioblastoma multiforme were selected for a comparative dosimetric evaluation with IMRT. Original target volumes, organs at risk (OAR), and dose-volume constraints were used for replanning with IMRT. Predicted isodose distributions, cumulative dose-volume histograms of target volumes and OAR, normal tissue integral dose, target coverage, dose conformity, and normal tissue sparing with 3D-CRT and IMRT planning were compared. Statistical analyses were performed to determine differences. Results: In all 20 patients, IMRT maintained equivalent target coverage, improved target conformity (conformity index [CI] 95% 1.52 vs. 1.38, p mean by 19.8% and D max by 10.7%), optic chiasm (D mean by 25.3% and D max by 22.6%), right optic nerve (D mean by 37.3% and D max by 28.5%), and left optic nerve (D mean by 40.6% and D max by 36.7%), p ≤ 0.01. This was achieved without increasing the total nontarget integral dose by greater than 0.5%. Overall, total integral dose was reduced by 7-10% with IMRT, p < 0.001, without significantly increasing the 0.5-5 Gy low-dose volume. Conclusions: These results indicate that IMRT treatment for high-grade gliomas allows for improved target conformity, better critical tissue sparing, and importantly does so without increasing integral dose and the volume of normal tissue exposed to low doses of radiation

Assessment of diurnal systemic dose of agrochemicals in regulatory toxicity testing--an integrated approach without additional animal use.

Science.gov (United States)

Saghir, Shakil A; Bartels, Michael J; Rick, David L; McCoy, Alene T; Rasoulpour, Reza J; Ellis-Hutchings, Robert G; Sue Marty, M; Terry, Claire; Bailey, Jason P; Billington, Richard; Bus, James S

2012-07-01

Integrated toxicokinetics (TK) data provide information on the rate, extent and duration of systemic exposure across doses, species, strains, gender, and life stages within a toxicology program. While routine for pharmaceuticals, TK assessments of non-pharmaceuticals are still relatively rare, and have never before been included in a full range of guideline studies for a new agrochemical. In order to better understand the relationship between diurnal systemic dose (AUC(24h)) and toxicity of agrochemicals, TK analyses in the study animals is now included in all short- (excluding acute), medium- and long-term guideline mammalian toxicity studies including reproduction/developmental tests. This paper describes a detailed procedure for the implementation of TK in short-, medium- and long-term regulatory toxicity studies, without the use of satellite animals, conducted on three agrochemicals (X11422208, 2,4-D and X574175). In these studies, kinetically-derived maximum doses (KMD) from short-term studies instead of, or along with, maximum tolerated doses (MTD) were used for the selection of the high dose in subsequent longer-term studies. In addition to leveraging TK data to guide dose level selection, the integrated program was also used to select the most appropriate method of oral administration (i.e., gavage versus dietary) of test materials for rat and rabbit developmental toxicity studies. The integrated TK data obtained across toxicity studies (without the use of additional/satellite animals) provided data critical to understanding differences in response across doses, species, strains, sexes, and life stages. Such data should also be useful in mode of action studies and to improve human risk assessments. Copyright © 2012 Elsevier Inc. All rights reserved.

Integrated doses calculation in evacuation scenarios of the neutron generator facility at Missouri S&T

Energy Technology Data Exchange (ETDEWEB)

Sharma, Manish K.; Alajo, Ayodeji B., E-mail: alajoa@mst.edu

2016-08-11

Any source of ionizing radiations could lead to considerable dose acquisition to individuals in a nuclear facility. Evacuation may be required when elevated levels of radiation is detected within a facility. In this situation, individuals are more likely to take the closest exit. This may not be the most expedient decision as it may lead to higher dose acquisition. The strategy followed in preventing large dose acquisitions should be predicated on the path that offers least dose acquisition. In this work, the neutron generator facility at Missouri University of Science and Technology was analyzed. The Monte Carlo N-Particle (MCNP) radiation transport code was used to model the entire floor of the generator's building. The simulated dose rates in the hallways were used to estimate the integrated doses for different paths leading to exits. It was shown that shortest path did not always lead to minimum dose acquisition and the approach was successful in predicting the expedient path as opposed to the approach of taking the nearest exit.

Adaptation of mechano-graphy to the measurement of integrated doses (1962); Adaptation de la mecanographie pour la comptabilisation des doses integrees (1962)

Energy Technology Data Exchange (ETDEWEB)

Tabardel-Brian, R; Dulau, J [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires

1962-07-01

Because of the increasing number of workers exposed to nuclear radiation, and with a view to avoiding doses above the maximum permissible dose for these workers, it was necessary to find a system whereby the total irradiation assimilated during periods of 3 and 12 consecutive months could be known and circulated rapidly, within 48 hours. The method chosen for this requires the services of the Mechano-graphic service of the Marcoule Centre. The present article describes the mechanical data processing solution to this problem. (authors) [French] Devant le nombre croissant de travailleurs appeles a etre exposes a une irradiation d'origine nucleaire et avec le souci constant d'eviter les depassements de Dose Maximum Admissible a ces agents, il convenait de trouver un systeme de diffusion de doses integrees capable de nous renseigner, dans un delai de 48 h, sur le capital irradiation integre au cours des periodes 3 mois et 12 mois consecutifs. Le mode de diffusion retenu fait appel aux services de l'Atelier Mecanographie du Centre de Marcoule. Le present rapport expose la solution mecanographique apportee a ce probleme. (auteurs)

Test methods of total dose effects in very large scale integrated circuits

International Nuclear Information System (INIS)

He Chaohui; Geng Bin; He Baoping; Yao Yujuan; Li Yonghong; Peng Honglun; Lin Dongsheng; Zhou Hui; Chen Yusheng

2004-01-01

A kind of test method of total dose effects (TDE) is presented for very large scale integrated circuits (VLSI). The consumption current of devices is measured while function parameters of devices (or circuits) are measured. Then the relation between data errors and consumption current can be analyzed and mechanism of TDE in VLSI can be proposed. Experimental results of 60 Co γ TDEs are given for SRAMs, EEPROMs, FLASH ROMs and a kind of CPU

Application of the Monte Carlo integration method in calculations of dose distributions in HDR-Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Baltas, D; Geramani, K N; Ioannidis, G T; Kolotas, C; Zamboglou, N [Strahlenklinik, Stadtische Kliniken Offenbach, Offenbach (Germany); Giannouli, S [Department of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece)

1999-12-31

Source anisotropy is a very important factor in brachytherapy quality assurance of high dose rate HDR Ir 192 afterloading stepping sources. If anisotropy is not taken into account then doses received by a brachytherapy patient in certain directions can be in error by a clinically significant amount. Experimental measurements of anisotropy are very labour intensive. We have shown that within acceptable limits of accuracy, Monte Carlo integration (MCI) of a modified Sievert integral (3D generalisation) can provide the necessary data within a much shorter time scale than can experiments. Hence MCI can be used for routine quality assurance schedules whenever a new design of HDR or PDR Ir 192 is used for brachytherapy afterloading. Our MCI calculation results are comparable with published experimental data and Monte Carlo simulation data for microSelectron and VariSource Ir 192 sources. We have shown not only that MCI offers advantages over alternative numerical integration methods, but also that treating filtration coefficients as radial distance-dependent functions improves Sievert integral accuracy at low energies. This paper also provides anisotropy data for three new Ir 192 sources, one for microSelectron-HDR and two for the microSelectron-PDR, for which data currently is not available. The information we have obtained in this study can be incorporated into clinical practice.

SU-E-T-166: Evaluation of Integral Dose in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Head and Neck Cancer Patient

Energy Technology Data Exchange (ETDEWEB)

Al-Basheer, A; Hunag, J; Kaminski, J; Dasher, B; Howington, J; Stewart, J; Martin, D; Kong, F; Jin, J [Georgia Regents University, Augusta, GA (Georgia)

2014-06-01

Purpose: Volumetric Modulated Arc Therapy (VMAT) usually achieves higher conformity of radiation doses to targets and less delivery time than Intensity Modulated Radiation Therapy (IMRT). We hypothesized that VMAT will increase integral dose (ID) to patients which will decrease the count of white blood count (WBC) lymphocytes, and consequently has a subsequent impact on the immune system. The purpose of this study is to evaluate the ID to patients undergoing IMRT and VMAT for Head and Neck cancers and its impact on the immune system. Methods: As a pilot study, 30 head and neck patients who received 9-fields IMRT or 3-arcs Radip-Arcbased VMAT were included in this study. Ten of these patients who received the VMAT plans were re-planned using IMRT with the same objectives. ID was calculated for all cases. All patients also had a baseline WBC obtained prior to treatment, and 3 sets of labs drawn during the course of radiation treatment. Results: For the 10 re-planned patients, the mean ID was 13.3 Gy/voxel (range 10.2–17.5 Gy/voxel) for the 9-fields IMRT plans, and was 15.9 Gy/voxel (range 12.4-20.9 Gy/voxel) for the 3-Arc VMAT plan (p=0.01). The integral dose was significant correlated with reducing WBC count during RT even when controlling for concurrent chemotherapy (R square =0.56, p=0.008). Conclusion: Although VMAT can deliver higher radiation dose conformality to targets, this benefit is achieved generally at the cost of greater integral doses to normal tissue outside the planning target volume (PTV). Lower WBC counts during RT were associated with higher Integral doses even when controlling for concurrent chemotherapy. This study is ongoing in our Institution to exam the impact of integral doses and WBC on overall survival.

Safety of dose escalation by simultaneous integrated boosting radiation dose within the primary tumor guided by 18FDG-PET/CT for esophageal cancer

International Nuclear Information System (INIS)

Yu, Wen; Cai, Xu-Wei; Liu, Qi; Zhu, Zheng-Fei; Feng, Wen; Zhang, Qin; Zhang, Ying-Jian; Yao, Zhi-Feng; Fu, Xiao-Long

2015-01-01

Purpose: To observe the safety of selective dose boost to the pre-treatment high 18 F-deoxyglucose (FDG) uptake areas of the esophageal GTV. Methods: Patients with esophageal squamous cell carcinoma were treated with escalating radiation dose of 4 levels, with a simultaneous integrated boost (SIB) to the pre-treatment 50% SUVmax area of the primary tumor. Patients received 4 monthly cycles of cisplatin and fluorouracil. Dose-limiting toxicity (DLT) was defined as any Grade 3 or higher acute toxicities causing continuous interruption of radiation for over 1 week. Results: From April 2012 to February 2014, dose has been escalated up to LEVEL 4 (70 Gy). All of the 25 patients finished the prescribed dose without DLT, and 10 of them developed Grade 3 acute esophagitis. One patient of LEVEL 2 died of esophageal hemorrhage within 1 month after completion of radiotherapy, which was not definitely correlated with treatment yet. Late toxicities remained under observation. With median follow up of 8.9 months, one-year overall survival and local control was 69.2% and 77.4%, respectively. Conclusions: Dose escalation in esophageal cancer based on 18 FDG-PET/CT has been safely achieved up to 70 Gy using the SIB technique. Acute toxicities were well tolerated, whereas late toxicities and long-term outcomes deserved further observation

Integrated technique for assessing environmental dose of radioactive waste storage installation

Energy Technology Data Exchange (ETDEWEB)

Bor-Jing Chang; Chien-Liang Shih; Ing-Jane Chen [Institute of Nuclear Energy Research, Lungtan, Taiwan (China); Ren-Dih Sheu; Shiang-Huei Jiang [National Tsing Hua University, Hsinchu, Taiwan (China); Shu-Jun Chang [Nuclear Science and Technology Association, Taiwan (China); Ruei-Ying Liao; Pei Yu; Chin-Yi Huang [Taiwan Power Company, Taipei, Taiwan (China)

2000-05-01

The ability to accurately predict exposure rates at large distances from a gamma radiation source is becoming increasingly important. This is because that the related regulation for the control of radiation levels in and around nuclear facilities becomes more stringent. Since the continuous increase of the radwaste storage capacity requirement on site, the requirement of a more realistic evaluation is very necessary. Those doses are usually at past time evaluated by QADCG/INER-2 code for direct dose and by SKYSHINE-III code for skyshine dose in which evaluation were over conservatively considered. This study is to update the evaluation code package accompanied with adequate methodology and to establish integrated analysis procedure. Thereafter, radiation doses can be accurately calculated in a reasonably conservative way. The purpose of the investigation is divided into three categories. First, SPECTRUM-506 is used instead of SPECTUM. Nuclide databases are enlarged from 100 up to 506. And the operation is ported to personal computer. Secondly, the QADCG/INER-3 code is developed to enhance the original QADCG/INER-2 code. The most important difference is the use of the geometric progression (GP) fitting function for the gamma-ray buildup factor. SKYSHINE-III code is replaced by McSKY and SKYDOSE codes. They are well benchmarked by using the Monte Carlo code MCNP and sensitive parameters are detailed investigated. Thirdly, the well developed analysis procedure is applicable for nuclear utility radwaste storage sites. Finally, the case studies were performed by using those packages to assess the radiological impact of utility radwaste storage site. The results are verified in detail by using Monte Carlo code MCNP and the results seems pretty consistent from both method. (author)

The integral biologically effective dose to predict brain stem toxicity of hypofractionated stereotactic radiotherapy

International Nuclear Information System (INIS)

Clark, Brenda G.; Souhami, Luis; Pla, Conrado; Al-Amro, Abdullah S.; Bahary, Jean-Paul; Villemure, Jean-Guy; Caron, Jean-Louis; Olivier, Andre; Podgorsak, Ervin B.

1998-01-01

Purpose: The aim of this work was to develop a parameter for use during fractionated stereotactic radiotherapy treatment planning to aid in the determination of the appropriate treatment volume and fractionation regimen that will minimize risk of late damage to normal tissue. Materials and Methods: We have used the linear quadratic model to assess the biologically effective dose at the periphery of stereotactic radiotherapy treatment volumes that impinge on the brain stem. This paper reports a retrospective study of 77 patients with malignant and benign intracranial lesions, treated between 1987 and 1995, with the dynamic rotation technique in 6 fractions over a period of 2 weeks, to a total dose of 42 Gy prescribed at the 90% isodose surface. From differential dose-volume histograms, we evaluated biologically effective dose-volume histograms and obtained an integral biologically-effective dose (IBED) in each case. Results: Of the 77 patients in the study, 36 had target volumes positioned so that the brain stem received more than 1% of the prescribed dose, and 4 of these, all treated for meningioma, developed serious late damage involving the brain stem. Other than type of lesion, the only significant variable was the volume of brain stem exposed. An analysis of the IBEDs received by these 36 patients shows evidence of a threshold value for late damage to the brain stem consistent with similar thresholds that have been determined for external beam radiotherapy. Conclusions: We have introduced a new parameter, the IBED, that may be used to represent the fractional effective dose to structures such as the brain stem that are partially irradiated with stereotactic dose distributions. The IBED is easily calculated prior to treatment and may be used to determine appropriate treatment volumes and fractionation regimens minimizing possible toxicity to normal tissue

Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy

Energy Technology Data Exchange (ETDEWEB)

Geier, M.; Astner, S.T.; Duma, M.N.; Putzhammer, J.; Winkler, C.; Molls, M.; Geinitz, H. [Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Jacob, V. [Universitaetsklinikum Freiburg (Germany). Klinik fuer Strahlenheilkunde; Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Care; Tromsoe Univ. (Norway). Inst. of Clinical Medicine

2012-05-15

The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity. (orig.)

Radioactivity in food and the environment: calculations of UK radiation doses using integrated methods

International Nuclear Information System (INIS)

Allott, Rob

2003-01-01

Dear Sir: I read with interest the paper by W C Camplin, G P Brownless, G D Round, K Winpenny and G J Hunt from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) on 'Radioactivity in food and the environment: calculations of UK radiation doses using integrated methods' in the December 2002 issue of this journal (J. Radiol. Prot. 22 371-88). The Environment Agency has a keen interest in the development of a robust methodology for assessing total doses which have been received by members of the public from authorised discharges of radioactive substances to the environment. Total dose in this context means the dose received from all authorised discharges and all exposure pathways (e.g. inhalation, external irradiation from radionuclides in sediment/soil, direct radiation from operations on a nuclear site, consumption of food etc). I chair a 'total retrospective dose assessment' working group with representatives from the Scottish Environment Protection Agency (SEPA), Food Standards Agency (FSA), National Radiological Protection Board, CEFAS and BNFL which began discussing precisely this issue during 2002. This group is a sub-group of the National Dose Assessment Working Group which was set up in April 2002 (J. Radiol. Prot. 22 318-9). The Environment Agency, Food Standards Agency and the Nuclear Installations Inspectorate previously undertook joint research into the most appropriate methodology to use for total dose assessment (J J Hancox, S J Stansby and M C Thorne 2002 The Development of a Methodology to Assess Population Doses from Multiple Source and Exposure Pathways of Radioactivity (Environment Agency R and D Technical Report P3-070/TR). This work came to broadly the same conclusion as the work by CEFAS, that an individual dose method is probably the most appropriate method to use. This research and that undertaken by CEFAS will help the total retrospective dose assessment working group refine a set of principles and a methodology for the

Independent dose calculation in IMRT for the Tps Iplan using the Clarkson modified integral; Calculo independiente de dosis en IMRT para el TPS Iplan usando la integral modificada de Clarkson

Energy Technology Data Exchange (ETDEWEB)

Adrada, A.; Tello, Z.; Garrigo, E.; Venencia, D., E-mail: jorge.alberto.adrada@gmail.com [Instituto Privado de Radioterapia, Obispo Oro 423, X5000BFI Cordoba (Argentina)

2014-08-15

Intensity-Modulated Radiation Therapy (IMRT) treatments require a quality assurance (Q A) specific patient before delivery. These controls include the experimental verification in dose phantom of the total plan as well as dose distributions. The use of independent dose calculation (IDC) is used in 3D-Crt treatments; however its application in IMRT requires the implementation of an algorithm that allows considering a non-uniform intensity beam. The purpose of this work was to develop IDC software in IMRT with MLC using the algorithm proposed by Kung (Kung et al. 2000). The software was done using Matlab programming. The Clarkson modified integral was implemented on each flowing, applying concentric rings for the dose determination. From the integral of each field was calculated the dose anywhere. One time finished a planning; all data are exported to a phantom where a Q A plan is generated. On this is calculated the half dose in a representative volume of the ionization chamber and the dose at the center of it. Until now 230 IMRT planning were analyzed carried out ??in the treatment planning system (Tps) Iplan. For each one of them Q A plan was generated, were calculated and compared calculated dose with the Tps, IDC system and measurement with ionization chamber. The average difference between measured and calculated dose with the IDC system was 0.4% ± 2.2% [-6.8%, 6.4%]. The difference between the measured and the calculated doses by the pencil-beam algorithm (Pb) of Tps was 2.6% ± 1.41% [-2.0%, 5.6%] and with the Monte Carlo algorithm was 0.4% ± 1.5% [-4.9%, 3.7%]. The differences of the carried out software are comparable to the obtained with the ionization chamber and Tps in Monte Carlo mode. (author)

Utilization of radiation protection gear for absorbed dose reduction: an integrative literature review

International Nuclear Information System (INIS)

Soares, Flavio Augusto Penna; Flor, Rita de Cassia; Pereira, Aline Garcia

2011-01-01

Objective: The present study was aimed at evaluating the relation between the use of radiation protection gear and the decrease in absorbed dose of ionizing radiation, thereby reinforcing the efficacy of its use by both the patients and occupationally exposed personnel. Materials and Methods: The integrative literature review method was utilized to analyze 21 articles, 2 books, 1 thesis, 1 monograph, 1 computer program, 4 pieces of database research (Instituto Brasileiro de Geografia e Estatistica and Departamento de Informatica do Sistema Unico de Saude) and 2 sets of radiological protection guidelines. Results: Theoretically, a reduction of 86% to 99% in the absorbed dose is observed with the use of radiation protection gear. In practice, however, the reduction may achieve 88% in patients submitted to conventional radiology, and 95% in patients submitted to computed tomography. In occupationally exposed individuals, the reduction is around 90% during cardiac catheterization, and 75% during orthopedic surgery. Conclusion: According to findings of several previous pieces of research, the use of radiation protection gear is a low-cost and effective way to reduce absorbed dose both for patients and occupationally exposed individuals. Thus, its use is necessary for the implementation of effective radioprotection programs in radiodiagnosis centers. (author)

Mobile-Dose: A Dose-Meter Designed for Use in Automatic Machineries for Dose Manipulation in Nuclear Medicine

Science.gov (United States)

de Asmundis, Riccardo; Boiano, Alfonso; Ramaglia, Antonio

2008-06-01

Mobile-Dose has been designed for a very innovative use: the integration in a robotic machinery for automatic preparation of radioactive doses, to be injected to patients in Nuclear Medicine Departments, with real time measurement of the activity under preparation. Mobile-Dose gives a constant measurement of the dose during the filling of vials or syringes, triggering the end of the filling process based on a predefined dose limit. Several applications of Mobile-Dose have been delivered worldwide, from Italian hospitals and clinics to European and Japanese ones. The design of such an instrument and its integration in robotic machineries, was required by an Italian company specialised in radiation protection tools for nuclear applications, in the period 2001-2003. At the time of its design, apparently no commercial instruments with a suitable interfacing capability to the external world existed: we designed it in order to satisfy all the strict requirements coming from the medical aspects (precision within 10%, repeatability, stability, time response) and from the industrial conceiving principles that are mandatory to ensure a good reliability in such a complicated environment. The instrument is suitable to be used in standalone mode too, thanks to its portability and compactness and to the intelligent operator panel programmed for this purpose.

A Dosimetric Comparison of Dose Escalation with Simultaneous Integrated Boost for Locally Advanced Non-Small-Cell Lung Cancer

Directory of Open Access Journals (Sweden)

Wenjuan Yang

2017-01-01

Full Text Available Background. Many studies have demonstrated that a higher radiotherapy dose is associated with improved outcomes in non-small-cell lung cancer (NSCLC. We performed a dosimetric planning study to assess the dosimetric feasibility of intensity-modulated radiation therapy (IMRT with a simultaneous integrated boost (SIB in locally advanced NSCLC. Methods. We enrolled twenty patients. Five different dose plans were generated for each patient. All plans were prescribed a dose of 60 Gy to the planning tumor volume (PTV. In the three SIB groups, the prescribed dose was 69 Gy, 75 Gy, and 81 Gy in 30 fractions to the internal gross tumor volume (iGTV. Results. The SIB-IMRT plans were associated with a significant increase in the iGTV dose (P < 0.05, without increased normal tissue exposure or prolonged overall treatment time. Significant differences were not observed in the dose to the normal lung in terms of the V5 and V20 among the four IMRT plans. The maximum dose (Dmax in the esophagus moderately increased along with the prescribed dose (P < 0.05. Conclusions. Our results indicated that escalating the dose by SIB-IMRT is dosimetrically feasible; however, systematic evaluations via clinical trials are still warranted. We have designed a further clinical study (which is registered with ClinicalTrials.gov, number NCT02841228.

Prescribing and evaluating target dose in dose-painting treatment plans

DEFF Research Database (Denmark)

Håkansson, Katrin; Specht, Lena; Aznar, Marianne C

2014-01-01

BACKGROUND: Assessment of target dose conformity in multi-dose-level treatment plans is challenging due to inevitable over/underdosage at the border zone between dose levels. Here, we evaluate different target dose prescription planning aims and approaches to evaluate the relative merit of such p......-painting and multi-dose-level plans. The tool can be useful for quality assurance of multi-center trials, and for visualizing the development of treatment planning in routine clinical practice....... of such plans. A quality volume histogram (QVH) tool for history-based evaluation is proposed. MATERIAL AND METHODS: Twenty head and neck cancer dose-painting plans with five prescription levels were evaluated, as well as clinically delivered simultaneous integrated boost (SIB) plans from 2010 and 2012. The QVH...

RSAC, Gamma Doses, Inhalation and Ingestion Doses, Fission Products Inventory after Fission Products Release

International Nuclear Information System (INIS)

Richardson, L.C.

1967-01-01

1 - Description of problem or function: RSAC generates a fission product inventory from a given set of reactor operating conditions and then computes the external gamma dose, the deposition gamma dose, and the inhalation-ingestion dose to critical body organs as a result of exposure to these fission products. Program output includes reactor operating history, fission product inventory, dosages, and ingestion parameters. 2 - Method of solution: The fission product inventory generated by the reactor operating conditions and the inventory remaining at various times after release are computed using the equations of W. Rubinson in Journal of Chemical Physics, Vol. 17, pages 542-547, June 1949. The external gamma dose and the deposition gamma dose are calculated by determining disintegration rates as a function of space and time, then integrating using Hermite's numerical techniques for the spatial dependence. The inhalation-ingestion dose is determined by the type and quantity of activity inhaled and the biological rate of decay following inhalation. These quantities are integrated with respect to time to obtain the dosage. The ingestion dose is related to the inhalation dose by an input constant

Dose planning and dose delivery in radiation therapy

International Nuclear Information System (INIS)

Knoeoes, T.

1991-01-01

A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

Text book of dose calculation for operators

International Nuclear Information System (INIS)

Aoyagi, Haruki; Gonda, Kozo

1979-07-01

This is a text book of dose calculation for the operators of the reprocessing factory of Power Reactor and Nuclear Fuel Development Corporation. The radiations considered are beta-ray and gamma-ray. The method used is a point attenuation nuclear integral method. Radiation sources are considered as the assemblies of point sources. Dose from each point source is calculated, then, total dose is obtained by the integration for all sources. Attenuation is calculated by considering the attenuation owing to distance and the absorption by absorbers. The build-up factor is introduced for the correction for scattered gamma-ray. The build-up factor is given in a table for various scatterers. The operators are able to calculate dose by themselves. The results of integral calculation expressed with formulas are given in graphs. (Kato, T.)

Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients

International Nuclear Information System (INIS)

Penoncello, Gregory P.; Ding, George X.

2016-01-01

The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2 cm"3 for head and neck plans and brain plans and a contiguous volume of 5 cm"3 for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens.

The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model

Energy Technology Data Exchange (ETDEWEB)

Neubeck, Claere von [German Cancer Consortium DKTK partner site Dresden, OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Geniza, Matthew J. [Molecular and Cellular Biology Program, Oregon State University, Corvallis OR 97331 (United States); Kauer, Paula M.; Robinson, R. Joe; Chrisler, William B. [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States); Sowa, Marianne B., E-mail: marianne.sowa@pnnl.gov [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States)

2015-05-15

Highlights: • Low doses of high LET radiation influence skin homeostasis. • Effects on proliferation and differentiation profiles are LET dependent. • Skin barrier function is not compromised following low dose exposure. - Abstract: Outside the protection of Earth's atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events at the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin's barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.

Feasibility study on an integrated AEC-grid device for the optimization of image quality and exposure dose in mammography

Science.gov (United States)

Kim, Kyo-Tae; Yun, Ryang-Young; Han, Moo-Jae; Heo, Ye-Ji; Song, Yong-Keun; Heo, Sung-Wook; Oh, Kyeong-Min; Park, Sung-Kwang

2017-10-01

Currently, in the radiation diagnosis field, mammography is used for the early detection of breast cancer. In addition, studies are being conducted on a grid to produce high-quality images. Although the grid ratio of the grid, which affects the scattering removal rate, must be increased to improve image quality, it increases the total exposure dose. While the use of automatic exposure control is recommended to minimize this problem, existing mammography equipment, unlike general radiography equipment, is mounted on the back of a detector. Therefore, the device is greatly affected by the detector and supporting device, and it is difficult to control the exposure dose. Accordingly, in this research, an integrated AEC-grid device that simultaneously performs AEC and grid functions was used to minimize the unnecessary exposure dose while removing scattering, thereby realizing superior image quality.

Evaluation of the Effects of Integrated Management Weed Control on Corn Field by Using Reduced Dose of Foramsulfuron and Nicosulfuron Herbicides

Directory of Open Access Journals (Sweden)

M. Matinfar

2011-09-01

Full Text Available In order to evaluate the effects of integrated weed management on weed control by using reduced herbicide dose, a field experiment was conducted in 2010 in Qazvin. The experiment was conducted in randomized complete block design with 24 treatments and 4 replications. The treatments were: different planting patterns at three levels (single row, square double rows and zigzag double row  plantings and doses of  Nicosulfuron and Foramsulfuron application at four levels (1, 1/5, 2 and 2/5 liters per hectare, The results showed that among the different planting patterns, zigzag planting reduced weed populations and their dry weights significantly. Foramsulfuron herbicide could control weeds better than Nicosulfuron. Among the herbicide dosages, 2/5 litter dose per hectare highly reduced weed density its dry weight as compared to one litter dose.

Mobile C-arm cone-beam CT for guidance of spine surgery: Image quality, radiation dose, and integration with interventional guidance

Energy Technology Data Exchange (ETDEWEB)

Schafer, S.; Nithiananthan, S.; Mirota, D. J.; Uneri, A.; Stayman, J. W.; Zbijewski, W.; Schmidgunst, C.; Kleinszig, G.; Khanna, A. J.; Siewerdsen, J. H. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 (United States); Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 (United States); Siemens Healthcare XP Division, Erlangen (Germany); Department of Orthopaedic Surgery, Johns Hopkins University, Baltimore, Maryland 21239 (United States); Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21202 and Department of Computer Science, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2011-08-15

Purpose: A flat-panel detector based mobile isocentric C-arm for cone-beam CT (CBCT) has been developed to allow intraoperative 3D imaging with sub-millimeter spatial resolution and soft-tissue visibility. Image quality and radiation dose were evaluated in spinal surgery, commonly relying on lower-performance image intensifier based mobile C-arms. Scan protocols were developed for task-specific imaging at minimum dose, in-room exposure was evaluated, and integration of the imaging system with a surgical guidance system was demonstrated in preclinical studies of minimally invasive spine surgery. Methods: Radiation dose was assessed as a function of kilovolt (peak) (80-120 kVp) and milliampere second using thoracic and lumbar spine dosimetry phantoms. In-room radiation exposure was measured throughout the operating room for various CBCT scan protocols. Image quality was assessed using tissue-equivalent inserts in chest and abdomen phantoms to evaluate bone and soft-tissue contrast-to-noise ratio as a function of dose, and task-specific protocols (i.e., visualization of bone or soft-tissues) were defined. Results were applied in preclinical studies using a cadaveric torso simulating minimally invasive, transpedicular surgery. Results: Task-specific CBCT protocols identified include: thoracic bone visualization (100 kVp; 60 mAs; 1.8 mGy); lumbar bone visualization (100 kVp; 130 mAs; 3.2 mGy); thoracic soft-tissue visualization (100 kVp; 230 mAs; 4.3 mGy); and lumbar soft-tissue visualization (120 kVp; 460 mAs; 10.6 mGy) - each at (0.3 x 0.3 x 0.9 mm{sup 3}) voxel size. Alternative lower-dose, lower-resolution soft-tissue visualization protocols were identified (100 kVp; 230 mAs; 5.1 mGy) for the lumbar region at (0.3 x 0.3 x 1.5 mm{sup 3}) voxel size. Half-scan orbit of the C-arm (x-ray tube traversing under the table) was dosimetrically advantageous (prepatient attenuation) with a nonuniform dose distribution ({approx}2 x higher at the entrance side than at isocenter

Committed equivalent organ doses and committed effective doses from intakes of radionuclides

CERN Document Server

Phipps, A W; Kendall, G M; Silk, T J; Stather, J W

1991-01-01

This report contains details of committed equivalent doses to individual organs for intakes by ingestion and inhalation of 1 mu m AMAD particles of 359 nuclides by infants aged 3 months, by children aged 1, 5, 10 and 15 years, and by adults. It complements NRPB-R245 which describes the changes which have taken place since the last NRPB compendium of dose per unit intake factors (dose coefficients) and gives summary tables. Information on the way committed doses increase with the integration period is given in NRPB-M289. The information given in these memoranda is also available as a microcomputer package - NRPB-SR245.

Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients.

Science.gov (United States)

Penoncello, Gregory P; Ding, George X

2016-01-01

The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2cm(3) for head and neck plans and brain plans and a contiguous volume of 5cm(3) for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens. Copyright © 2016 American Association of Medical Dosimetrists. Published by

A cost-effective technique for integrating personal radiation dose assessment with personal gravimetric sampling

International Nuclear Information System (INIS)

Strydom, R.; Rolle, R.; Van der Linde, A.

1992-01-01

During recent years there has been an increasing awareness internationally of radiation levels in the mining and milling of radioactive ores, including those from non-uranium mines. A major aspect of radiation control is concerned with the measurement of radiation levels and the assessment of radiation doses incurred by individual workers. Current techniques available internationally for personnel monitoring of radiation exposures are expensive and there is a particular need to reduce the cost of personal radiation monitoring in South African gold mines because of the large labour force employed. In this regard the obvious benefits of integrating personal radiation monitoring with existing personal monitoring systems already in place in South African gold mines should be exploited. A system which can be utilized for this purpose is personal gravimetric sampling. A new cost-effective technique for personal radiation monitoring, which can be fully integrated with the personal gravimetric sampling strategy being implemented on mines, has been developed in South Africa. The basic principles of this technique and its potential in South African mines are described. 9 refs., 7 figs

Simple approximation for estimating centerline gamma absorbed dose rates due to a continuous Gaussian plume

International Nuclear Information System (INIS)

Overcamp, T.J.; Fjeld, R.A.

1987-01-01

A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals which were developed for estimating long-term dose due to a sector-averaged Gaussian plume. Estimates of tissue absorbed dose rates for the new approach and for the uniform cloud model were compared to numerical integration of the dose integral over a Gaussian plume distribution

Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

International Nuclear Information System (INIS)

Braby, L. A.; Reece, W. D.; Hsu, W. H.

2003-01-01

Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation experiments. We have also developed 4.3 mm diameter ion chambers with both tissue equivalent and carbon walls for the purpose of measuring dose mean lineal energy due to all radiations and due to all radiations except neutrons, respectively. By adjusting the gas pressure in the ion chamber, it can be made to simulate tissue volumes from a few nanometers to a few millimeters in diameter. The charge is integrated for 0.1 seconds, and the resulting pulse height is recorded by a multi channel analyzer. The system has been used in a variety of photon and neutron radiation fields, and measured values of dose and dose mean lineal energy are consistent with values extrapolated from measurements made by other techniques at much lower dose rates. It is expected that this technique will prove to be much more reliable than extrapolations from measurements made at low dose rates because these low dose rate exposures generally do not accurately reproduce the attenuation and

Recovery of the proliferative and functional integrity of mouse bone marrow in long-term cultures established after whole-body irradiation at different doses and dose rates

International Nuclear Information System (INIS)

Bierkens, J.G.; Hendry, J.H.; Testa, N.G.

1991-01-01

Injury inflicted upon the bone marrow stroma following whole-body irradiation and its repair over a 1-year period has been assessed in murine long-term bone marrow cultures established at increasing time intervals after irradiation. Different doses at different dose rates (10 Gy at 0.05 cGy/min, 4.5 Gy and 10 Gy at 1.6 cGy/min, and 4 x 4.5 Gy [3 weeks between doses] at 60 cGy/min) were chosen so as to maximize differences in effect in the stroma. The cellularity of the adherent layer in long-term cultures established 1 month after irradiation was reduced by 40%-90% depending on the dose and dose rate. Simultaneous with the poor ability of the marrow to form adherent layers, the cumulative spleen colony-forming unit (CFU-S) and granulocyte-macrophage colony-forming cell (GM-CFC) production over a 7-week period was reduced to 0% and 30% of control cultures, respectively. The slow recovery of the adherent layer was paralleled by an increase in the numbers of CFU-S and GM-CFC in the supernatant. Cultures established from repeatedly irradiated mice performed poorly over the entire 1-year period. Whereas the regeneration of the stroma was near complete 1 year after irradiation, the CFU-S and GM-CFC levels reached only between 50% and 80% of control cultures, respectively. Also, the concentration of CFU-S and GM-CFC in the supernatant remained persistently lower in cultures established from irradiated mice as compared to control cultures. The levels of sulfated glycosaminoglycans, which have been implicated in the establishment of the functional integrity of the microenvironment, were not reduced in the adherent layers at any time after irradiation. These results indicate that the regeneration of the stroma is accompanied by an incomplete recovery of active hemopoiesis in vitro

Half-dose non-contrast CT in the investigation of urolithiasis: image quality improvement with third-generation integrated circuit CT detectors.

Science.gov (United States)

Wang, Jun; Kang, Tony; Arepalli, Chesnal; Barrett, Sarah; O'Connell, Tim; Louis, Luck; Nicolaou, Savvakis; McLaughlin, Patrick

2015-06-01

The objective of this study is to establish the effect of third-generation integrated circuit (IC) CT detector on objective image quality in full- and half-dose non-contrast CT of the urinary tract. 51 consecutive patients with acute renal colic underwent non-contrast CT of the urinary tract using a 128-slice dual-source CT before (n = 24) and after (n = 27) the installation of third-generation IC detectors. Half-dose images were generated using projections from detector A using the dual-source RAW data. Objective image noise in the liver, spleen, right renal cortex, and right psoas muscle was compared between DC and IC cohorts for full-dose and half-dose images reconstructed with FBP and IR algorithms using 1 cm(2) regions of interest. Presence and size of obstructing ureteric calculi were also compared for full-dose and half-dose reconstructions using DC and IC detectors. No statistical difference in age and lateral body size was found between patients in the IC and DC cohorts. Radiation dose, as measured by size-specific dose estimates, did not differ significantly either between the two cohorts (10.02 ± 4.54 mGy IC vs. 12.28 ± 7.03 mGy DC). At full dose, objective image noise was not significantly lower in the IC cohort as compared to the DC cohort for the liver, spleen, and right psoas muscle. At half dose, objective image noise was lower in the IC cohort as compared to DC cohort at the liver (21.32 IC vs. 24.99 DC, 14.7% decrease, p 0.05 for all comparisons). Third-generation IC detectors result in lower objective image noise at full- and half-radiation dose levels as compared with traditional DC detectors. The magnitude of noise reduction was greater at half-radiation dose indicating that the benefits of using novel IC detectors are greater in low and ultra-low-dose CT imaging.

Doses from portable gauges

International Nuclear Information System (INIS)

Linauskas, S.H.

1988-08-01

Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose

Integrated boost IMRT with FET-PET-adapted local dose escalation in glioblastomas. Results of a prospective phase II study

International Nuclear Information System (INIS)

Piroth, M.D.; Pinkawa, M.; Holy, R.; Forschungszentrum Juelich GmbH

2012-01-01

Dose escalations above 60 Gy based on MRI have not led to prognostic benefits in glioblastoma patients yet. With positron emission tomography (PET) using [ 18 F]fluorethyl-L-tyrosine (FET), tumor coverage can be optimized with the option of regional dose escalation in the area of viable tumor tissue. In a prospective phase II study (January 2008 to December 2009), 22 patients (median age 55 years) received radiochemotherapy after surgery. The radiotherapy was performed as an MRI and FET-PET-based integrated-boost intensity-modulated radiotherapy (IMRT). The prescribed dose was 72 and 60 Gy (single dose 2.4 and 2.0 Gy, respectively) for the FET-PET- and MR-based PTV-FET (72 Gy) and PTV-MR (60 Gy) . FET-PET and MRI were performed routinely for follow-up. Quality of life and cognitive aspects were recorded by the EORTC-QLQ-C30/QLQ Brain20 and Mini-Mental Status Examination (MMSE), while the therapy-related toxicity was recorded using the CTC3.0 and RTOG scores. Median overall survival (OS) and disease-free survival (DFS) were 14.8 and 7.8 months, respectively. All local relapses were detected at least partly within the 95% dose volume of PTV-MR (60 Gy) . No relevant radiotherapy-related side effects were observed (excepted alopecia). In 2 patients, a pseudoprogression was observed in the MRI. Tumor progression could be excluded by FET-PET and was confirmed in further MRI and FET-PET imaging. No significant changes were observed in MMSE scores and in the EORTC QLQ-C30/QLQ-Brain20 questionnaires. Our dose escalation concept with a total dose of 72 Gy, based on FET-PET, did not lead to a survival benefit. Acute and late toxicity were not increased, compared with historical controls and published dose-escalation studies. (orig.)

Integrated boost IMRT with FET-PET-adapted local dose escalation in glioblastomas. Results of a prospective phase II study

Energy Technology Data Exchange (ETDEWEB)

Piroth, M.D.; Pinkawa, M.; Holy, R. [RWTH Aachen University Hospital (Germany). Dept. of Radiation Oncology; Forschungszentrum Juelich GmbH (DE). Juelich-Aachen Research Alliance (JARA) - Section JARA-Brain] (and others)

2012-04-15

Dose escalations above 60 Gy based on MRI have not led to prognostic benefits in glioblastoma patients yet. With positron emission tomography (PET) using [{sup 18}F]fluorethyl-L-tyrosine (FET), tumor coverage can be optimized with the option of regional dose escalation in the area of viable tumor tissue. In a prospective phase II study (January 2008 to December 2009), 22 patients (median age 55 years) received radiochemotherapy after surgery. The radiotherapy was performed as an MRI and FET-PET-based integrated-boost intensity-modulated radiotherapy (IMRT). The prescribed dose was 72 and 60 Gy (single dose 2.4 and 2.0 Gy, respectively) for the FET-PET- and MR-based PTV-FET{sub (72 Gy)} and PTV-MR{sub (60 Gy)}. FET-PET and MRI were performed routinely for follow-up. Quality of life and cognitive aspects were recorded by the EORTC-QLQ-C30/QLQ Brain20 and Mini-Mental Status Examination (MMSE), while the therapy-related toxicity was recorded using the CTC3.0 and RTOG scores. Median overall survival (OS) and disease-free survival (DFS) were 14.8 and 7.8 months, respectively. All local relapses were detected at least partly within the 95% dose volume of PTV-MR{sub (60 Gy)}. No relevant radiotherapy-related side effects were observed (excepted alopecia). In 2 patients, a pseudoprogression was observed in the MRI. Tumor progression could be excluded by FET-PET and was confirmed in further MRI and FET-PET imaging. No significant changes were observed in MMSE scores and in the EORTC QLQ-C30/QLQ-Brain20 questionnaires. Our dose escalation concept with a total dose of 72 Gy, based on FET-PET, did not lead to a survival benefit. Acute and late toxicity were not increased, compared with historical controls and published dose-escalation studies. (orig.)

Pulse and integral optically stimulated luminescence (OSL). Similarities and dissimilarities to thermoluminescence (TL) dose dependence and dose-rate effects

International Nuclear Information System (INIS)

Chen, R.; Leung, P.L.

2000-01-01

Optically stimulated luminescence (OSL) and thermoluminescence (Tl) are two possible methods to monitor the absorbed radiation in solid samples, and therefore are utilized for dosimetry. For this application, two properties are desirable, namely, linear dose dependence of the measured quantity and dose-rate independence. For Tl, different kinds of super linear dose dependence have been reported in the literature in different materials, and in some cases, dose-rate dependence has also been found. These have been explained as being the result of competition. In OSL, some recent works reported on super linear dose dependence in annealed samples. In the present work, we explain the possible occurrence of these phenomena in OSL by solving numerically the relevant rate equations governing the process during irradiation, relaxation and read-out (heating or light stimulation). The results show that for short pulse OSL, quadratic dose dependence can be expected when only one trapping state and one kind of recombination center are involved and when the excitation starts with empty traps and centers. With the short pulse OSL, the calculation also reveals a possible dose-rate effect. Under the same circumstances, the area under the OSL curve depends linearly on the dose. The dependence of the whole area under the OSL curve on the dose is shown to be super linear when a disconnected trapping state or radiationless center take part in the process. Also, dose-rate effect can be expected in these cases, although no experimental effect of this sort has been reported so far. In pulse OSL, the analogy is made between the measured intensity and the initial rise range of non-first order Tl, whereas for the total area OSL, there is a nearly full analogy with the dose behavior of the Tl maximum. (Author)

Low dose radiation effects: an integrative european approach (Risc-Rad Project) coordinated by the Cea

International Nuclear Information System (INIS)

Sabatier, L.

2006-01-01

RISC-RAD (Radiosensitivity of Individuals and Susceptibility to Cancer induced by ionizing Radiations) is an Integrated Project funded by the European Commission under 6. Framework Programme / EURATOM. RISC-RAD started on 1. January 2004 for a duration of four years. Coordinated by Cea (Dr Laure Sabatier), it involves 11 European countries (Austria, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Spain, Sweden and the United Kingdom) and 29 research institutions. Objectives: Exposures to low and protracted doses of ionizing radiation are very frequent in normal living environment, at work places, in industry and in medicine. Effects of these exposures on human health cannot be reliably assessed by epidemiological methods, nor is thoroughly understood by biologists. RISC-RAD project proposes to help bridging the gap of scientific knowledge about these effects. To achieve this goal, a necessary key step is to understand the basic mechanisms by which radiation induces cancer. Studying this multistage process in an integrated way, the project offers a new biological approach characterised by and clear-cut and objective-driven scientific policy: the project is focused on the effects of low doses (less than 100 mSv) and protracted doses of radiation. It aims at identifying new parameters that take into account the differences in radiation responses between individuals. A group of modelers works closely with the experimental teams in order to better quantify the risks associated with low and protracted doses. Research work is divided into five work packages interacting closely with each other. WP1 is dedicated to DNA damage. Ionizing Radiation (IR) produce a broad spectrum of base modifications and DNA strand breaks of different kinds, among which double-strand breaks and 'clustered damage' which is thought to be a major feature in biological effectiveness of IR. The aim of Work Package 1 is to improve understanding of the initial DNA damage induced by

Device for simulation of integral dose distribution in multifield radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Belyakov, E K; Voronin, V V; Kolosova, V F; Moskalev, A I; Marova, Yu M; Stavitskii, R V; Yarovoi, V S

1974-11-15

Described is a device for simulation of the sum dose distribution at multifield radiation therapy; the device comprises a mechanical unit on which the emission sources and detectors are mounted, an electromechanical scanning equipment, amplifiers, an adder, a position sensor and a recording instrument. The device suggested raises an accuracy of a sick man radiation program elaboration at a remote multifield radiation therapy, permits to estimate the irradiated medium heterogeneity and beam shaper influence on the sum dose distribution and also ensured the information on the sum dose distribution of the relative or absolute units. Additional filters simulating heterogeneity and beam shaping conditions of ionizing radiation may be mounted between the quantum emission sources and detectors, and an amplifier with a variable amplification factor may be placed between the adders and printers. Thus it is possible to obtain a sum dose distribution at static methods of the remote radiation therapy at a high degree of accuracy (up to +-10%).

Neutrons in active proton therapy. Parameterization of dose and dose equivalent

Energy Technology Data Exchange (ETDEWEB)

Schneider, Uwe; Haelg, Roger A. [Univ. of Zurich (Switzerland). Dept. of Physics; Radiotherapy Hirslanden AG, Aarau (Switzerland); Lomax, Tony [Paul Scherrer Institute, Villigen (Switzerland). Center for Proton Therapy

2017-08-01

One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85 cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138 MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160 MeV or 177 MeV instead of 138 MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.

Transition of some type of integrated circuits into latch-up mode under effect of ionizing radiation of large dose rate

International Nuclear Information System (INIS)

Berdichevskij, B.E.; Madzharova, T.B.

1986-01-01

Some types of integrated circuits (IC) are almost short-circuit, i.e. they transit to the latch-up regime under the effect of ionizing radiation pulses of large dose rate. The results of investigation into IC under their transition into the latch-up regime at supply voltage of 10 V are presented. It is shown that IC stably transit to the latch-up regime if the dinistor current becomes at least equal to the photocurrent. At bias reduction from 15 to 6 V the dose rate at which the latch-up arises grows from 2.5x10 9 to 3.5x10 9 rad (Si)/s. Burn-out of supply busbar is the usual type of IC failure at latch-up arising. Measures for IC protection from latch-up are shown. In some IC the latch-up is formed beginning from a certain critical value of dose rate, the so-called ''windows'' of latch-up

Optimized probes for dose rate measurements at local government sites and in emergency planning zones and their integration into measurement networks

International Nuclear Information System (INIS)

Kuca, Petr; Helebrant, Jan; Cespirova, Irena; Judas, Libor; Skala, Lukas

2015-01-01

The results of a security project aimed at the development of a radiation situation monitoring system using optimized probes for dose rate measurements are described. The system is suitable for use at local government sites as well as at other sites. The system includes dose rate measurement probes with the variable configuration functionality (detection part), equipment for data transfer to a central workplace (communication part) and application for collection, storage and administration of the results and their presentation at a website (presentation part). The dosimetric and other operational properties of the probes were tested and the feasibility of their integration into measurement networks using the IMS central application was examined. (orig.)

Methods, safety, and early clinical outcomes of dose escalation using simultaneous integrated and sequential boosts in patients with locally advanced gynecologic malignancies.

Science.gov (United States)

Boyle, John; Craciunescu, Oana; Steffey, Beverly; Cai, Jing; Chino, Junzo

2014-11-01

To evaluate the safety of dose escalated radiotherapy using a simultaneous integrated boost technique in patients with locally advanced gynecological malignancies. Thirty-nine women with locally advanced gynecological malignancies were treated with intensity modulated radiation therapy utilizing a simultaneous integrated boost (SIB) technique for gross disease in the para-aortic and/or pelvic nodal basins, sidewall extension, or residual primary disease. Women were treated to 45Gy in 1.8Gy fractions to elective nodal regions. Gross disease was simultaneously treated to 55Gy in 2.2Gy fractions (n=44 sites). An additional sequential boost of 10Gy in 2Gy fractions was delivered if deemed appropriate (n=29 sites). Acute and late toxicity, local control in the treated volumes (LC), overall survival (OS), and distant metastases (DM) were assessed. All were treated with a SIB to a dose of 55Gy. Twenty-four patients were subsequently treated with a sequential boost to a median dose of 65Gy. Median follow-up was 18months. Rates of acute>grade 2 gastrointestinal (GI), genitourinary (GU), and hematologic (heme) toxicities were 2.5%, 0%, and 30%, respectively. There were no grade 4 acute toxicities. At one year, grade 1-2 late GI toxicities were 24.5%. There were no grade 3 or 4 late GI toxicities. Rates of grade 1-2 late GU toxicities were 12.7%. There were no grade 3 or 4 late GU toxicities. Dose escalated radiotherapy using a SIB results in acceptable rates of acute toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of total dose of ionizing radiation on integrated circuits

Energy Technology Data Exchange (ETDEWEB)

Silveira, Marcilei A.G.; Cirne, K.H.; Gimenez, S.; Santos, R.B.B. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Added, N.; Barbosa, M.D.L.; Medina, N.H.; Tabacniks, M.H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Lima, J.A. de; Seixas Junior, L.E.; Melo, W. [Centro de Tecnologia da Informacao Paulo Archer, Sao Paulo, SP (Brazil)

2011-07-01

Full text: The study of ionizing radiation effects on materials used in electronic devices is of great relevance for the progress of global technological development and, particularly, it is a necessity in some strategic areas in Brazil. Electronic circuits are strongly influenced by radiation and the need for IC's featuring radiation hardness is largely growing to meet the stringent environment in space electronics. On the other hand, aerospace agencies are encouraging both scientific community and semiconductors industry to develop hardened-by-design components using standard manufacturing processes to achieve maximum performance, while significantly reducing costs. To understand the physical phenomena responsible for changes in devices exposed to ionizing radiation several kinds of radiation should then be considered, among them alpha particles, protons, gamma and X-rays. Radiation effects on the integrated circuits are usually divided into two categories: total ionizing dose (TID), a cumulative dose that shifts the threshold voltage and increases transistor's off-state current; single events effects (SEE), a transient effect which can deposit charge directly into the device and disturb the properties of electronic circuits. TID is one of the most common effects and may generate degradation in some parameters of the CMOS electronic devices, such as the threshold voltage oscillation, increase of the sub-threshold slope and increase of the off-state current. The effects of ionizing radiation are the creation of electron-hole pairs in the oxide layer changing operation mode parameters of the electronic device. Indirectly, there will be also changes in the device due to the formation of secondary electrons from the interaction of electromagnetic radiation with the material, since the charge carriers can be trapped both in the oxide layer and in the interface with the oxide. In this work we have investigated the behavior of MOSFET devices fabricated with

First-principles X-ray absorption dose calculation for time-dependent mass and optical density.

Science.gov (United States)

Berejnov, Viatcheslav; Rubinstein, Boris; Melo, Lis G A; Hitchcock, Adam P

2018-05-01

A dose integral of time-dependent X-ray absorption under conditions of variable photon energy and changing sample mass is derived from first principles starting with the Beer-Lambert (BL) absorption model. For a given photon energy the BL dose integral D(e, t) reduces to the product of an effective time integral T(t) and a dose rate R(e). Two approximations of the time-dependent optical density, i.e. exponential A(t) = c + aexp(-bt) for first-order kinetics and hyperbolic A(t) = c + a/(b + t) for second-order kinetics, were considered for BL dose evaluation. For both models three methods of evaluating the effective time integral are considered: analytical integration, approximation by a function, and calculation of the asymptotic behaviour at large times. Data for poly(methyl methacrylate) and perfluorosulfonic acid polymers measured by scanning transmission soft X-ray microscopy were used to test the BL dose calculation. It was found that a previous method to calculate time-dependent dose underestimates the dose in mass loss situations, depending on the applied exposure time. All these methods here show that the BL dose is proportional to the exposure time D(e, t) ≃ K(e)t.

Enhanced low dose rate radiation effect test on typical bipolar devices

International Nuclear Information System (INIS)

Liu Minbo; Chen Wei; Yao Zhibin; He Baoping; Huang Shaoyan; Sheng Jiangkun; Xiao Zhigang; Wang Zujun

2014-01-01

Two types of bipolar transistors and nine types bipolar integrated circuit were selected in the irradiation experiment at different "6"0Co γ dose rate. The base current of bipolar transistor and input bias current of amplifier and comparator was measured, low dose enhance factor of test device was obtained. The results show that bipolar device have enhanced low dose rate sensitivity, enhancement factor of bipolar integrated circuit was bigger than that of transistor, and enhanced low dose rate sensitivity greatly varied with different structure and process of bipolar device. (authors)

Choline PET based dose-painting in prostate cancer - Modelling of dose effects

International Nuclear Information System (INIS)

Niyazi, Maximilian; Bartenstein, Peter; Belka, Claus; Ganswindt, Ute

2010-01-01

Several randomized trials have documented the value of radiation dose escalation in patients with prostate cancer, especially in patients with intermediate risk profile. Up to now dose escalation is usually applied to the whole prostate. IMRT and related techniques currently allow for dose escalation in sub-volumes of the organ. However, the sensitivity of the imaging modality and the fact that small islands of cancer are often dispersed within the whole organ may limit these approaches with regard to a clear clinical benefit. In order to assess potential effects of a dose escalation in certain sub-volumes based on choline PET imaging a mathematical dose-response model was developed. Based on different assumptions for α/β, γ50, sensitivity and specificity of choline PET, the influence of the whole prostate and simultaneous integrated boost (SIB) dose on tumor control probability (TCP) was calculated. Based on the given heterogeneity of all potential variables certain representative permutations of the parameters were chosen and, subsequently, the influence on TCP was assessed. Using schedules with 74 Gy within the whole prostate and a SIB dose of 90 Gy the TCP increase ranged from 23.1% (high detection rate of choline PET, low whole prostate dose, high γ50/ASTRO definition for tumor control) to 1.4% TCP gain (low sensitivity of PET, high whole prostate dose, CN + 2 definition for tumor control) or even 0% in selected cases. The corresponding initial TCP values without integrated boost ranged from 67.3% to 100%. According to a large data set of intermediate-risk prostate cancer patients the resulting TCP gains ranged from 22.2% to 10.1% (ASTRO definition) or from 13.2% to 6.0% (CN + 2 definition). Although a simplified mathematical model was employed, the presented model allows for an estimation in how far given schedules are relevant for clinical practice. However, the benefit of a SIB based on choline PET seems less than intuitively expected. Only under the

Urban contamination and dose model

International Nuclear Information System (INIS)

Robertson, E.; Barry, P.J.

1995-10-01

Nuclear power reactors and other nuclear facilities are being built near or even within urban centres. Accidental releases of radionuclides to the atmosphere in built-up areas result in radiological exposure pathways that differ from those caused by releases in rural environments. Other than inhalation, exposure pathways involve external radiation from the plume while it passes and from radioactivity deposited onto the many and varied surfaces after it has passed. Radiation fields inside buildings are attenuated but many people are potentially exposed so while individual doses may be relatively low, population integrated doses may be high enough to cause concern. It is important, therefore, to assess the potential exposures and to estimate the cost-effectiveness of dose reduction measures in urban environments. This report describes a model developed to carry out such assessments. The model draws heavily on experience gained in European cities after their contamination fallout from the Chernobyl accident. Input is time integrated concentrations of specific radionuclides in urban air, obtained either by direct measurement or by prediction using an atmospheric dispersion model. The code includes default values for site specific variables and transfer parameters but the user is invited if desired to enter other values from the keyboard. Output is the time integrated dose rates for individuals selected because of the characteristic living, working and recreational habits. An accompanying manual documents the technical background on which the model is based and leads a first-time suer through various steps and operations encountered while the model is running. (author). 60 refs., 10 tabs., 1 fig

From physical dose constraints to equivalent uniform dose constraints in inverse radiotherapy planning

International Nuclear Information System (INIS)

Thieke, Christian; Bortfeld, Thomas; Niemierko, Andrzej; Nill, Simeon

2003-01-01

Optimization algorithms in inverse radiotherapy planning need information about the desired dose distribution. Usually the planner defines physical dose constraints for each structure of the treatment plan, either in form of minimum and maximum doses or as dose-volume constraints. The concept of equivalent uniform dose (EUD) was designed to describe dose distributions with a higher clinical relevance. In this paper, we present a method to consider the EUD as an optimization constraint by using the method of projections onto convex sets (POCS). In each iteration of the optimization loop, for the actual dose distribution of an organ that violates an EUD constraint a new dose distribution is calculated that satisfies the EUD constraint, leading to voxel-based physical dose constraints. The new dose distribution is found by projecting the current one onto the convex set of all dose distributions fulfilling the EUD constraint. The algorithm is easy to integrate into existing inverse planning systems, and it allows the planner to choose between physical and EUD constraints separately for each structure. A clinical case of a head and neck tumor is optimized using three different sets of constraints: physical constraints for all structures, physical constraints for the target and EUD constraints for the organs at risk, and EUD constraints for all structures. The results show that the POCS method converges stable and given EUD constraints are reached closely

Enjebi Island dose assessment

International Nuclear Information System (INIS)

Robison, W.L.; Conrado, C.L.; Phillips, W.A.

1987-07-01

We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137 Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

Integrated effects of reduction dose of nitrogen fertilizer and mode of biofertilizer application on soil health under mung bean cropping system

Directory of Open Access Journals (Sweden)

Naba Kumar Mondal

2014-12-01

Full Text Available To study the integrated effects of reduced dose of chemical fertilizer with different methods and times of application of Rhizobium biofertilizer on soil health and fertility under mung bean (Vigna radiata cropping, field experiments were carried out during three years (2009, 2010, and 2011 in West Bengal, India, in randomized block design. In the first year, varietal screening of mung bean under recommended dose of chemical fertilizer (20:40:20 were performed with five available varieties adapted to local climate. Reduced nitrogen fertilizer doses (20%, 30%, 40%, 50%, and 60% and the recommended dose, as well as the Rhizobium biofertilizer application (basal, soil, and spray, were done, and data were recorded for pH, electrical conductivity, organic carbon, total nitrogen, total phosphorus, total potassium, and bacterial population of soil, both before sowing and after harvesting. The results indicated significant improvement in the soil quality with gradual buildup of soil macronutrient status after harvesting of crop. Application of biofertilizer has contributed significantly towards higher soil organic matter, nitrogen, phosphorus, and potassium. The use of biofertilizer significantly improved soil bacterial population count in the soil thereby increasing the soil health.

A real time dose monitoring and dose reconstruction tool for patient specific VMAT QA and delivery

International Nuclear Information System (INIS)

Tyagi, Neelam; Yang Kai; Gersten, David; Yan Di

2012-01-01

Purpose: To develop a real time dose monitoring and dose reconstruction tool to identify and quantify sources of errors during patient specific volumetric modulated arc therapy (VMAT) delivery and quality assurance. Methods: The authors develop a VMAT delivery monitor tool called linac data monitor that connects to the linac in clinical mode and records, displays, and compares real time machine parameters with the planned parameters. A new measure, called integral error, keeps a running total of leaf overshoot and undershoot errors in each leaf pair, multiplied by leaf width, and the amount of time during which the error exists in monitor unit delivery. Another tool reconstructs Pinnacle 3 ™ format delivered plan based on the saved machine logfile and recalculates actual delivered dose in patient anatomy. Delivery characteristics of various standard fractionation and stereotactic body radiation therapy (SBRT) VMAT plans delivered on Elekta Axesse and Synergy linacs were quantified. Results: The MLC and gantry errors for all the treatment sites were 0.00 ± 0.59 mm and 0.05 ± 0.31°, indicating a good MLC gain calibration. Standard fractionation plans had a larger gantry error than SBRT plans due to frequent dose rate changes. On average, the MLC errors were negligible but larger errors of up to 6 mm and 2.5° were seen when dose rate varied frequently. Large gantry errors occurred during the acceleration and deceleration process, and correlated well with MLC errors (r= 0.858, p= 0.0004). PTV mean, minimum, and maximum dose discrepancies were 0.87 ± 0.21%, 0.99 ± 0.59%, and 1.18 ± 0.52%, respectively. The organs at risk (OAR) doses were within 2.5%, except some OARs that showed up to 5.6% discrepancy in maximum dose. Real time displayed normalized total positive integral error (normalized to the total monitor units) correlated linearly with MLC (r= 0.9279, p < 0.001) and gantry errors (r= 0.742, p= 0.005). There is a strong correlation between total integral

Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

CERN Document Server

Braby, L A; Reece, W D

2003-01-01

Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation exp...

Dose calculation in eye brachytherapy with Ir-192 threads using the Sievert integral and corrected by attenuation and scattering with the Meisberg polynomials

International Nuclear Information System (INIS)

Vivanco, M.G. Bernui de; Cardenas R, A.

2006-01-01

The ocular brachytherapy many times unique alternative to conserve the visual organ in patients of ocular cancer, one comes carrying out in the National Institute of Neoplastic Illnesses (INEN) using threads of Iridium 192; those which, they are placed in radial form on the interior surface of a spherical cap of gold of 18 K; the cap remains in the eye until reaching the prescribed dose by the doctor. The main objective of this work is to be able to calculate in a correct and practical way the one time that the treatment of ocular brachytherapy should last to reach the dose prescribed by the doctor. To reach this objective I use the Sievert integral corrected by attenuation effects and scattering (Meisberg polynomials); calculating it by the Simpson method. In the calculations by means of the Sievert integral doesn't take into account the scattering produced by the gold cap neither the variation of the constant of frequency of exposure with the distance. The calculations by means of Sievert integral are compared with those obtained using the Monte Carlo Penelope simulation code, where it is observed that they agree at distances of the surface of the cap greater or equal to 2mm. (Author)

beta. and. gamma. -comparative dose estimates on Enewetak Atoll

Energy Technology Data Exchange (ETDEWEB)

Crase, K.W.; Gudiksen, P.H.; Robison, W.L. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

1982-05-01

Enewetak Atoll in the Pacific is used for atmospheric testing of U.S. nuclear weapons. Beta dose and ..gamma..-ray exposure measurements were made on two islands of the Enewetak Atoll during July-August 1976 to determine the ..beta.. and low energy ..gamma..-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a ..beta..-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to ..beta..- or low energy ..gamma..-contribution. The contribution at any particular site, however, is reduced by vegetation. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey. Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the ..beta..'s or low energy ..gamma..'s, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

Dose and dose reduction in computed tomography; Dosis und Dosisreduktion in der Computertomografie

Energy Technology Data Exchange (ETDEWEB)

Lell, Michael [Klinikum Nuernberg (Germany). Inst. fuer Radiologie und Nuklearmedizin; Paracelsus Medical Univ. Nuernberg (Germany); Wucherer, Michael [Klinikum Nuernberg (Germany). Inst. fuer Medizinische Physik; Kachelriess, Marc [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany)

2017-06-15

CT is widely used in medical imaging due to high availability, relatively low cost, and excellent diagnostic yield. Newer applications like coronary CTA, CT colonography, and CT perfusion imaging are integrated in clinical pathways. Although there is a high level of consensus that the benefits of CT exceeds the risks of radiation exposure for appropriate indications, concerns have been raised regarding the potential of cancer induction. Keeping dose as low as reasonably achievable remains the most important task. Dose reduction strategies are presented and discussed.

Integration of Fricke gel dosimetry with Ag nanoparticles for experimental dose enhancement determination in theranostics

International Nuclear Information System (INIS)

Vedelago, J.; Valente, M.; Mattea, F.

2017-10-01

The use and implementation of nanoparticles in medicine has grown exponentially in the last twenty years. Their main applications include drug delivery, theranostics, tissue engineering and magneto function. Dosimetry techniques can take advantage of inorganic nanoparticles properties and their combination with gel dosimetry techniques could be used as a first step for their later inclusion in radio-diagnostics or radiotherapy treatments. This work presents preliminary results of properly synthesized and purify silver nanoparticles integration with Fricke gel dosimeters. Used nanoparticles presented mean sizes ranging from 2 to 20 nm, with a lognormal distribution. Xylenol orange concentration in Fricke gel dosimeter was adjust in order to allow sample optical readout, accounting nanoparticles plasmon. Dose enhancement was assessed irradiating dosimeters setting X-ray beams energies below and above silver K-edge. (Author)

Integration of Fricke gel dosimetry with Ag nanoparticles for experimental dose enhancement determination in theranostics

Energy Technology Data Exchange (ETDEWEB)

Vedelago, J.; Valente, M. [Instituto de Fisica Enrique Gaviola - CONICET, Av. Medina Allende s/n, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Mattea, F., E-mail: jvedelago@famaf.unc.edu.ar [Universidad Nacional de Cordoba, FAMAF, Laboratorio de Investigacion e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Av. Medina Allende s/n, Ciudad Universitaria, X5000HUA Cordoba (Argentina)

2017-10-15

The use and implementation of nanoparticles in medicine has grown exponentially in the last twenty years. Their main applications include drug delivery, theranostics, tissue engineering and magneto function. Dosimetry techniques can take advantage of inorganic nanoparticles properties and their combination with gel dosimetry techniques could be used as a first step for their later inclusion in radio-diagnostics or radiotherapy treatments. This work presents preliminary results of properly synthesized and purify silver nanoparticles integration with Fricke gel dosimeters. Used nanoparticles presented mean sizes ranging from 2 to 20 nm, with a lognormal distribution. Xylenol orange concentration in Fricke gel dosimeter was adjust in order to allow sample optical readout, accounting nanoparticles plasmon. Dose enhancement was assessed irradiating dosimeters setting X-ray beams energies below and above silver K-edge. (Author)

Dose distribution of non-coplanar irradiation

Energy Technology Data Exchange (ETDEWEB)

Fukui, Toshiharu; Wada, Yoichi; Takenaka, Eiichi

1987-02-01

Non-coplanar irradiations were applied to the treatment of brain tumor. The dose distribution around the target area due to non-coplanar irradiation was half less than the dose when coplanar irradiation used. Integral volume dose due to this irradiation was not always less than that due to conventional opposing or rotational irradiation. This irradiation has the better application to the following;as a boost therapy, glioblastoma multiforme;as a radical therapy, recurrent brain tumor, well differentiated brain tumor such as craniopharyngioma, hypophyseal tumor etc and AV-malformation.

Integrated pharmacokinetics/pharmacodynamics parameters-based dosing guidelines of enrofloxacin in grass carp Ctenopharyngodon idella to minimize selection of drug resistance.

Science.gov (United States)

Xu, Lijuan; Wang, Hao; Yang, Xianle; Lu, Liqun

2013-06-25

Antibiotic resistance has become a serious global problem and is steadily increasing worldwide in almost every bacterial species treated with antibiotics. In aquaculture, the therapeutic options for the treatment of A. hydrophila infection were only limited to several antibiotics, which contributed for the fast-speed emergence of drug tolerance. Accordingly, the aim of this study was to establish a medication regimen to prevent drug resistant bacteria. To determine a rational therapeutic guideline, integrated pharmacodynamics and pharmacokinetics parameters were based to predict dose and dosage interval of enrofloxacin in grass carp Ctenopharyngodon idella infected by a field-isolated A. hydrophila strain. The pathogenic A. hydrophila strain (AH10) in grass carp was identified and found to be sensitive to enrofloxacin. The mutant selection window (MSW) of enrofloxacin on isolate AH10 was determined to be 0.5-3 μg/mL based on the mutant prevention concentration (MPC) and minimum inhibitory concentration (MIC) value. By using high-performance liquid chromatography (HPLC) system, the Pharmacokinetic (PK) parameters of enrofloxacin and its metabolite ciprofloxacin in grass carp were monitored after a single oral gavage of 10, 20, 30 μg enrofloxacin per g body weight. Dosing of 30 μg/g resulted in serum maximum concentration (Cmax) of 7.151 μg/mL, and concentration in serum was above MPC till 24 h post the single dose. Once-daily dosing of 30 μg/g was determined to be the rational choice for controlling AH10 infection and preventing mutant selection in grass carp. Data of mean residue time (MRT) and body clearance (CLz) indicated that both enrofloxacin and its metabolite ciprofloxacin present similar eliminating rate and pattern in serum, muscle and liver. A withdraw time of more than 32 d was suggested based on the drug eliminating rate and pharmacokinetic model described by a polyexponential equation. Based on integrated PK/PD parameters (AUC/MIC, Cmax/MIC, and T

Photon dose conversion coefficients for the human teeth in standard irradiation geometries

Energy Technology Data Exchange (ETDEWEB)

Ulanovsky, A; Wieser, A; Zankl, M; Jacob, P

2005-07-01

Photon dose conversion coefficients for the human tooth materials are computed in energy range from 0.01 to 10 MeV by the Monte Carlo method. The voxel phantom Golem of the human body with newly defined tooth region and a modified version of the EGS4 code have been used to compute the coefficients for 30 tooth cells with different locations and materials. The dose responses are calculated for cells representing buccal and lingual enamel layers. The computed coefficients demonstrate a strong dependence on energy and geometry of the radiation source and a weaker dependence on location of the enamel voxels. For isotropic and rotational radiation fields the enamel dose does not show a significant dependence on tooth sample locations. The computed coefficients are used to convert from absorbed dose in teeth to organ dose or to integral air kerma. Examples of integral conversion factors from enamel dose to air kerma are given for several photon fluences specific for the Mayak reprocessing plant in Russia. The integral conversion factors are strongly affected by the energy and angular distributions of photon fluence, which are important characteristics of an exposure scenario for reconstruction of individual occupational doses. (orig.)

Dose Rate Determination from Airborne Gamma-ray Spectra

DEFF Research Database (Denmark)

Bargholz, Kim

1996-01-01

The standard method for determination of ground level dose rates from airborne gamma-ray is the integral count rate which for a constant flying altitude is assumed proportional to the dose rate. The method gives reasonably results for natural radioactivity which almost always has the same energy...

Population pharmacokinetic model of THC integrates oral, intravenous, and pulmonary dosing and characterizes short- and long-term pharmacokinetics.

Science.gov (United States)

Heuberger, Jules A A C; Guan, Zheng; Oyetayo, Olubukayo-Opeyemi; Klumpers, Linda; Morrison, Paul D; Beumer, Tim L; van Gerven, Joop M A; Cohen, Adam F; Freijer, Jan

2015-02-01

Δ(9)-Tetrahydrocannobinol (THC), the main psychoactive compound of Cannabis, is known to have a long terminal half-life. However, this characteristic is often ignored in pharmacokinetic (PK) studies of THC, which may affect the accuracy of predictions in different pharmacologic areas. For therapeutic use for example, it is important to accurately describe the terminal phase of THC to describe accumulation of the drug. In early clinical research, the THC challenge test can be optimized through more accurate predictions of the dosing sequence and the wash-out between occasions in a crossover setting, which is mainly determined by the terminal half-life of the compound. The purpose of this study is to better quantify the long-term pharmacokinetics of THC. A population-based PK model for THC was developed describing the profile up to 48 h after an oral, intravenous, and pulmonary dose of THC in humans. In contrast to earlier models, the current model integrates all three major administration routes and covers the long terminal phase of THC. Results show that THC has a fast initial and intermediate half-life, while the apparent terminal half-life is long (21.5 h), with a clearance of 38.8 L/h. Because the current model characterizes the long-term pharmacokinetics, it can be used to assess the accumulation of THC in a multiple-dose setting and to forecast concentration profiles of the drug under many different dosing regimens or administration routes. Additionally, this model could provide helpful insights into the THC challenge test used for the development of (novel) compounds targeting the cannabinoid system for different therapeutic applications and could improve decision making in future clinical trials.

A remotely operated drug delivery system with dose control

KAUST Repository

Yi, Ying; Kosel, Jü rgen

2017-01-01

include an effective actuation stimulus and a controllable dose release mechanism. This work focuses on remotely powering an implantable drug delivery system and providing a high degree of control over the released dose. This is accomplished by integration

MELODI: The 'Multidisciplinary European Low-Dose Initiative'

International Nuclear Information System (INIS)

Belli, M.; Salomaa, S.; Ottolenghi, A.

2011-01-01

The importance of research to reduce uncertainties in risk assessment of low and protracted exposures is now recognised globally. In Europe a new initiative, called 'Multidisciplinary European Low Dose Initiative' (MELODI), has been proposed by a 'European High Level and Expert Group on low-dose risk research' (www.hleg.de), aimed at integrating national and EC (Euratom) efforts. Five national organisations: BfS (DE), CEA (FR), IRSN (FR), ISS (IT) and STUK (FI), with the support of the EC, have initiated the creation of MELODI by signing a letter of intent. In the forthcoming years, MELODI will integrate in a step-by-step approach EU institutions with significant programmes in the field and will be open to other scientific organisations and stakeholders. A key role of MELODI is to develop and maintain over time a strategic research agenda (SRA) and a road map of scientific priorities within a multidisciplinary approach, and to transfer the results for the radiation protection system. Under the coordination of STUK a network has been proposed in the 2009 Euratom Programme, called DoReMi (Low-Dose Research towards Multidisciplinary Integration), which can help the integration process within the MELODI platform. DoReMi and the First MELODI Open Workshop, organised by BfS in September 2009, are now important inputs for the European SRA. (authors)

Image quality and radiation dose of lower extremity CT angiography at 70 kVp on an integrated circuit detector dual-source computed tomography.

Science.gov (United States)

Qi, Li; Zhao, Yan'E; Zhou, Chang Sheng; Spearman, James V; Renker, Matthias; Schoepf, U Joseph; Zhang, Long Jiang; Lu, Guang Ming

2015-06-01

Despite the well-established requirement for radiation dose reduction there are few studies examining the potential for lower extremity CT angiography (CTA) at 70 kVp. To compare the image quality and radiation dose of lower extremity CTA at 70 kVp using a dual-source CT system with an integrated circuit detector to similar studies at 120 kVp. A total of 62 patients underwent lower extremity CTA. Thirty-one patients were examined at 70 kVp using a second generation dual-source CT with an integrated circuit detector (70 kVp group) and 31 patients were evaluated at 120 kVp using a first generation dual-source CT (120 kVp group). The attenuation and image noise were measured and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Two radiologists assessed image quality. Radiation dose was compared. The mean attenuation of the 70 kVp group was higher than the 120 kVp group (575 ± 149 Hounsfield units [HU] vs. 258 ± 38 HU, respectively, P < 0.001) as was SNR (44.0 ± 22.0 vs 32.7 ± 13.3, respectively, P = 0.017), CNR (39.7 ± 20.6 vs 26.6 ± 11.7, respectively, P = 0.003) and the mean image quality score (3.7 ± 0.1 vs. 3.2 ± 0.3, respectively, P < 0.001). The inter-observer agreement was good for the 70 kVp group and moderate for the 120 kVp group. The dose-length product was lower in the 70 kVp group (264.5 ± 63.1 mGy × cm vs. 412.4 ± 81.5 mGy × cm, P < 0.001). Lower extremity CTA at 70 kVp allows for lower radiation dose with higher SNR, CNR, and image quality when compared with standard 120 kVp. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

SKYSHIN: A computer code for calculating radiation dose over a barrier

International Nuclear Information System (INIS)

Atwood, C.L.; Boland, J.R.; Dickman, P.T.

1986-11-01

SKYSHIN is a computer code for calculating the radioactive dose (mrem), when there is a barrier between the point source and the receptor. The two geometrical configurations considered are: the source and receptor separated by a rectangular wall, and the source at the bottom of a cylindrical hole in the ground. Each gamma ray traveling over the barrier is assumed to be scattered at a single point. The dose to a receptor from such paths is numerically integrated for the total dose, with symmetry used to reduce the triple integral to a double integral. The buildup factor used along a straight line through air is based on published data, and extrapolated in a stable way to low energy levels. This buildup factor was validated by comparing calculated and experimental line-of-sight doses. The entire code shows good agreement to limited field data. The code runs on a CDC or on a Vax computer, and could be modified easily for others

Committed dose equivalent in the practice of radiological protection

International Nuclear Information System (INIS)

Nenot, J.C.; Piechowski, J.

1985-01-01

In the case of internal exposure, the dose is not received at the moment of exposure, as happens with external exposure, since the incorporated radionuclide irradiates the various organs and tissues during the time it is present in the body. By definition, the committed dose equivalent corresponds to the received dose integrated over 50 years from the date of intake. In order to calculate it, one has to know the intake activity and the value of the committed dose equivalent per unit of intake activity. The uncertainties of the first parameter are such that the committed dose equivalent can only be regarded as an order of magnitude and not as a very accurate quantity. The use of it is justified, however, for, like the dose equivalent for external exposure, it expresses the risk of stochastic effects for the individual concerned since these effects, should they appear, would do so only after a latent period which is generally longer than the dose integration time. Moreover, the use of the committed dose equivalent offers certain advantages for dosimetric management, especially when it is simplified. A practical problem which may arise is that the annual dose limit is apparently exceeded by virtue of the fact that one is taking account, in the first year, of doses which will actually be received only in the following years. These problems are rare enough in practice to be dealt with individually in each case. (author)

Gamma-ray spectra and doses from the Little Boy replica

International Nuclear Information System (INIS)

Moss, C.E.; Lucas, M.C.; Tisinger, E.W.; Hamm, M.E.

1984-01-01

Most radiation safety guidelines in the nuclear industry are based on the data concerning the survivors of the nuclear explosions at Hiroshima and Nagasaki. Crucial to determining these guidelines is the radiation from the explosions. We have measured gamma-ray pulse-height distributions from an accurate replica of the Little Boy device used at Hiroshima, operated at low power levels near critical. The device was placed outdoors on a stand 4 m from the ground to minimize environmental effects. The power levels were based on a monitor detector calibrated very carefully in independent experiments. High-resolution pulse-height distributions were acquired with a germanium detector to identify the lines and to obtain line intensities. The 7631 to 7645 keV doublet from neutron capture in the heavy steel case was dominant. Low-resolution pulse-height distributions were acquired with bismuth-germanate detectors. We calculated flux spectra from these distributions using accurately measured detector response functions and efficiency curves. We then calculated dose-rate spectra from the flux spectra using a flux-to-dose-rate conversion procedure. The integral of each dose-rate spectrum gave an integral dose rate. The integral doses at 2 m ranged from 0.46 to 1.03 mrem per 10 13 fissions. The output of the Little Boy replica can be calculated with Monte Carlo codes. Comparison of our experimental spectra, line intensities, and integral doses can be used to verify these calculations at low power levels and give increased confidence to the calculated values from the explosion at Hiroshima. These calculations then can be used to establish better radiation safety guidelines. 7 references, 7 figures, 2 tables

Dose-volume considerations in stereotaxic brain radiation therapy

International Nuclear Information System (INIS)

Houdek, P.V.; Schwade, J.G.; Pisciotta, V.J.; Medina, A.J.; Lewin, A.A.; Abitbol, A.A.; Serago, C.F.

1988-01-01

Although brain radiation therapy experience suggests that a gain in the therapeutic ratio may be achieved by optimizing the dose-volume relationship, no practical system for quantitative assessment of dose-volume data has been developed. This presentation describes the rationale for using the integral dose function for this purpose and demonstrates that with the use of a conventional treatment planning computer and a series of computed tomographic scans, first-order optimization of the dose-volume function can be accomplished in two steps: first, high-dose volume is minimized by selecting an appropriate treatment technique and tumor margin, and then dosage is maximized by calculating the brain tolerance dose as a function of the irradiated volume

Dose Evaluation of Fractionated Schema and Distance From Tumor to Spinal Cord for Spinal SBRT with Simultaneous Integrated Boost: A Preliminary Study.

Science.gov (United States)

Yang, Hao; Cai, Bo-ning; Wang, Xiao-shen; Cong, Xiao-hu; Xu, Wei; Wang, Jin-yuan; Yang, Jun; Xu, Shou-ping; Ju, Zhong-jian; Ma, Lin

2016-02-23

BACKGROUND This study investigated and quantified the dosimetric impact of the distance from the tumor to the spinal cord and fractionation schemes for patients who received stereotactic body radiation therapy (SBRT) and hypofractionated simultaneous integrated boost (HF-SIB). MATERIAL AND METHODS Six modified planning target volumes (PTVs) for 5 patients with spinal metastases were created by artificial uniform extension in the region of PTV adjacent spinal cord with a specified minimum tumor to cord distance (0-5 mm). The prescription dose (biologic equivalent dose, BED) was 70 Gy in different fractionation schemes (1, 3, 5, and 10 fractions). For PTV V100, Dmin, D98, D95, and D1, spinal cord dose, conformity index (CI), V30 were measured and compared. RESULTS PTV-to-cord distance influenced PTV V100, Dmin, D98, and D95, and fractionation schemes influenced Dmin and D98, with a significant difference. Distances of ≥2 mm, ≥1 mm, ≥1 mm, and ≥0 mm from PTV to spinal cord meet dose requirements in 1, 3, 5, and 10 fractionations, respectively. Spinal cord dose, CI, and V30 were not impacted by PTV-to-cord distance and fractionation schemes. CONCLUSIONS Target volume coverage, Dmin, D98, and D95 were directly correlated with distance from the spinal cord for spine SBRT and HF-SIB. Based on our study, ≥2 mm, ≥1 mm, ≥1 mm, and ≥0 mm distance from PTV to spinal cord meets dose requirements in 1, 3, 5 and 10 fractionations, respectively.

beta- and gamma-Comparative dose estimates on Eniwetok Atoll

Energy Technology Data Exchange (ETDEWEB)

Crase, K.W.; Gudiksen, P.H.; Robison, W.L.

1982-05-01

Eniwetok Atoll is one of the Pacific atolls used for atmospheric testing of U.S. nuclear weapons. Beta dose and gamma-ray exposure measurements were made on two islands of the Eniwetok Atoll during July-August 1976 to determine the beta and low energy gamma-contribution to the total external radiation doses to the returning Marshallese. Measurements were made at numerous locations with thermoluminescent dosimeters (TLD), pressurized ionization chambers, portable NaI detectors, and thin-window pancake GM probes. Results of the TLD measurements with and without a beta-attenuator indicate that approx. 29% of the total dose rate at 1 m in air is due to beta- or low energy gamma-contribution. The contribution at any particular site, however, is somewhat dependent on ground cover, since a minimal amount of vegetation will reduce it significantly from that over bare soil, but thick stands of vegetation have little effect on any further reductions. Integral 30-yr external shallow dose estimates for future inhabitants were made and compared with external dose estimates of a previous large scale radiological survey (En73). Integral 30-yr shallow external dose estimates are 25-50% higher than whole body estimates. Due to the low penetrating ability of the beta's or low energy gamma's, however, several remedial actions can be taken to reduce the shallow dose contribution to the total external dose.

Maintaining occupational dose ALARA through work management

International Nuclear Information System (INIS)

Khan, A. H.

1999-01-01

Canadian philosophy in keeping occupational dose ALARA has been to train staff in radiation safety so that they can be fully responsible for participating in minimizing the risks associated with the hazardous work. Senior managers actively promote high standards of performance in dose reduction techniques as a means for integrating ALARA into the operation and maintenance of the station by all personnel. Minimizing radiation dose is accomplished by applying cost effective work management techniques such as Job Safety Analysis, pre-job briefings and establishing and achieving radiation dose goals. Radiation dose goals are used as a management tool for involving all work groups in reducing doses as well as providing a means of assessing the effectiveness of dose reduction actions. ALARA, along with conventional safety, is used as a lever to raise the standard of quality of work and to overall build a safety culture. (author). 4 figs

Integrated Worker Radiation Dose Assessment for the K Basins

International Nuclear Information System (INIS)

NELSON, J.V.

1999-01-01

This report documents an assessment of the radiation dose workers at the K Basins are expected to receive in the process of removing spent nuclear fuel from the storage basins. The K Basins (K East and K West) are located in the Hanford 100K Area

Dose-rate effects of low-dropout voltage regulator at various biases

International Nuclear Information System (INIS)

Wang Yiyuan; Zheng Yuzhan; Gao Bo; Chen Rui; Fei Wuxiong; Lu Wu; Ren Diyuan

2010-01-01

A low-dropout voltage regulator, LM2941, was irradiated by 60 Co γ-rays at various dose rates and biases for investigating the total dose and dose rate effects. The radiation responses show that the key electrical parameters, including its output and dropout voltage, and the maximum output current, are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias. The integrated circuits damage change with the dose rates and biases, and the dose-rate effects are relative to its electric field. (authors)

Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

Science.gov (United States)

Dantas, A. R. V.; Gauthier, M. K.; Coss, J. R.

1985-01-01

The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

Calculation of the primary dose in the absence of electronic equilibrium

International Nuclear Information System (INIS)

Petrov, D.E.

1995-01-01

In a multilayered media at points close to the boundary of any two layers of different electronic densities, the absorbed dose due to primary radiation, can be estimated by means of secondary electrons. Assuming monoenergetic megavoltage photons incident on a two layered media, the Compton effect is a predominant mode of interaction, the primary dose is due to the electrons set into motion from the first interaction. The dose is divided into components from the upper and lower layers. The beam width must be large enough so that all electrons scattered at some angle could pass through detector point. General expression for the dose is a product of the initial photon flux at some depth, the Klein-Nisha cross section, and the ionizational mass stopping power integrated over azimuthal angle. The factor taking into account real geometry is out of the sign of integral. The latter depends only on the distance between the interface and detector for the given consequence of layers. At the interface there is a peak or drop of the dose determined by the ratio of the stopping powers under the sign of the integral. At points beyond the interface the dose decreases or increases up to electronic equilibrium region where the absorbed dose and the kerma are parallel to each other. The peak width at the base is determined by the free range of the electron with the maximum possible energy after the Compton scattering

The national dose registry of Canada

International Nuclear Information System (INIS)

1982-04-01

In 1951, when the National Dosimetry Service was established by the Department of National Health and Welfare, a system of centralized records was created as an integral part of the new service. Over the last few years the dose record system has expanded in size and content, and improvements have been made in the physical methods of record storage. In addition to the 250 000 individual dose records from the National Dosimetry Service, the National Dose Registry now includes internal tritium and external doses from nuclear generating stations, and radon daughter exposures submitted by uranium mining companies. With the increase in the use of radiation in the medical, industrial and research fields, it is becoming more important to have a comprehensive and readily accessible centralized record system. The Canadian National Dose Registry is particularly suited for continuing health risk studies of radiation workers and provides a base for future epidemiological studies

A repository released-dose model for the evaluation of long-lived fission product transmutation effectiveness

International Nuclear Information System (INIS)

Davidson, J.W.

1995-01-01

A methodology has been developed to quantify the total integrated dose due to a radionuclide species i emplaced in a geologic repository; the focus is on the seven long-lived fission products (LLFPs). The methodology assumes continuous exposure water contaminated with species i at the accessible environment (i.e., just beyond the geologic barrier afforded by the geologic repository). The dose integration is performed out to a reference post-release time. The integrated dose is a function of the total initial inventory of radionuclide i the repository, the time at which complete and instantaneous failure of the engineered barrier (e.g., waste canister) in, a geologic repository occurs, the fractional dissolution rate (from waste solid form) of radionuclide i in ground water, the ground water travel time to the accessible environment, the retardation factor (sorption on the geologic media) for radionuclide i, the time after radionuclide begins to enter the biosphere. In order to assess relative dose, the ratio of total integrated dose to that for a reference LLFP species j (e.g., 99 Tc) was defined. This ratio is a measure of the relative benefit of transmutation of other LLFPs compared to 99 Tc. This methodology was further developed in order to quantify the integrated dose reduction per neutron utilized for LLFP transmutation in accelerator-driven transmutation technologies (ADTT). This measure of effectiveness is a function of the integrated dose due to LLFP species i, the number of total captures in LLFP species i chain per LLFP nuclide fed to the chain at equilibrium, and the number of total captures in related transmutation product (TP) chains per capture in the LLFP species i chain. To assess relative transmutation effectiveness, the ratio of integrated dose reduction per neutron utilization to that for a reference LLFP species j (e.g., 99 Tc) was defined. This relative measure of effectiveness was evaluated LLFP transmutation strategy

Manual of dose evaluation from atmospheric releases

Energy Technology Data Exchange (ETDEWEB)

Shirvaikar, V V; Abrol, V [Health Physics Division, Bhabha Atomic Research Centre, Bombay (India)

1978-07-01

The problem of dose evaluation from atmospheric releases is reduced to simple arithmetic by giving tables of concentrations and time integrated concentrations for instantaneous plumes and long time (1 year), sector averaged plumes for distances upto 10 km, effective release heights of upto 200 m and the six Pasquill stability classes. Correction factors for decay, depletion due to deposition and rainout are also given. Inhalation doses, immersion doses and contamination levels can be obtained from these by using multiplicative factors tabulated for various isotopes of significance. Tables of external gamma doses from plume are given separately for various gamma energies. Tables are also given to evaluate external beta and gamma dose rates from contaminated surfaces. The manual also discusses the basic diffusion model relevant to the problem. (author)

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

Updated radiological dose assessment of Bikini and Eneu Islands at Bikini Atoll

International Nuclear Information System (INIS)

Robison, W.L.; Mount, M.E.; Phillips, W.A.; Stuart, M.L.; Thompson, S.E.; Conrado, C.L.; Stoker, A.C.

1982-01-01

This report is part of a continuing effort to refine dose assessments for resettlement options at Bikini Atoll. Radionuclide concentration data developed at Bikini Atoll since 1977 have been used in conjunction with recent dietary information and current dose models to develop the annual dose rate and 30- and 50-y integral doses presented here for Bikini and Eneu Island living patterns. The terrestrial food chain is the most significant exposure pathway--it contributes more than 50% of the total dose--and external gamma exposure is the second most significant pathway. Other pathways evaluated are the marine food chain, drinking water, and inhalation. Cesium-137 produces more than 85% of the predicted dose; 90 Sr is the second most significant radionuclide; 60 Co contributes to the external gamma exposure in varying degrees, but is a small part of the total predicted dose; the transuranic radionuclides contribute a small portion of the total predicted lung and bone doses but do present a long-term source of exposure. Maximum annual dose rates for Bikini Island are about 1 rem/y for the whole body and bone marrow when imported foods are available and about 1.9 rem/y when imports are unavailable. Maximum annual dose rates for Eneu Island when imports are available are 130 mrem/y for the whole body and 136 mrem/y for bone marrow. Similar doses when imported foods are unavailable are 245 and 263 mrem/y, respectively. The 30-y integral doses for Bikini Island are about 23 rem for whole body and bone marrow when imported foods are available and more than 40 rem when imports are unavailable. The Eneu Island 30-y integral doses for whole body and bone marrow are about 3 rem when imports are available and 5.5 and 6.1 rem, respectively, when imports are unavailable. Doses from living patterns involving some combination of Bikini and Eneu Islands fall between the doses listed above for each island separately

Sustainability Instruction in High Doses: Results From Incorporation of Multiple InTeGrate Modules Into an Environmental Science Class

Science.gov (United States)

Rademacher, L. K.

2017-12-01

The Interdisciplinary Teaching about Earth for a Sustainable Future (InTeGrate) community has developed extensive courses and modules designed for broad adoption into geoscience classrooms in diverse environments. I participated in a three-semester research project designed to test the efficacy of incorporating "high doses" (minimum 3 modules or 18 class periods) of InTeGrate materials into a course, in my case, an introductory environmental science class. InTeGrate materials were developed by groups of instructors from a range of institutions across the US. These materials include an emphasis on systems thinking, interdisciplinary approaches, and sustainability, and those themes are woven throughout the modules. The three semesters included a control in which no InTeGrate materials were used, a pilot in which InTeGrate materials were tested, and a treatment semesters in which tested materials were modified as needed and fully implemented into the course. Data were collected each semester on student attitudes using the InTeGrate Attitudinal Instrument (pre and post), a subset of Geoscience Literacy Exam questions (pre and post), and a series of assessments and essay exam questions (post only). Although results suggest that learning gains were mixed, changes in attitudes pre- and post-instruction were substantial. Changes in attitudes regarding the importance of sustainable employers, the frequency of self-reported individual sustainable actions, and motivation level for creating a sustainable society were observed in the control and treatment semesters, with the treatment semester showing the greatest gains. Importantly, one of the biggest differences between the control and treatment semesters is the reported impact that the course had on influencing students' sustainable behaviors. The treatment semester course impacted students' sustainable behaviors far more than the control semester.

Integration profile and safety of an adenovirus hybrid-vector utilizing hyperactive sleeping beauty transposase for somatic integration.

Directory of Open Access Journals (Sweden)

Wenli Zhang

Full Text Available We recently developed adenovirus/transposase hybrid-vectors utilizing the previously described hyperactive Sleeping Beauty (SB transposase HSB5 for somatic integration and we could show stabilized transgene expression in mice and a canine model for hemophilia B. However, the safety profile of these hybrid-vectors with respect to vector dose and genotoxicity remains to be investigated. Herein, we evaluated this hybrid-vector system in C57Bl/6 mice with escalating vector dose settings. We found that in all mice which received the hyperactive SB transposase, transgene expression levels were stabilized in a dose-dependent manner and that the highest vector dose was accompanied by fatalities in mice. To analyze potential genotoxic side-effects due to somatic integration into host chromosomes, we performed a genome-wide integration site analysis using linker-mediated PCR (LM-PCR and linear amplification-mediated PCR (LAM-PCR. Analysis of genomic DNA samples obtained from HSB5 treated female and male mice revealed a total of 1327 unique transposition events. Overall the chromosomal distribution pattern was close-to-random and we observed a random integration profile with respect to integration into gene and non-gene areas. Notably, when using the LM-PCR protocol, 27 extra-chromosomal integration events were identified, most likely caused by transposon excision and subsequent transposition into the delivered adenoviral vector genome. In total, this study provides a careful evaluation of the safety profile of adenovirus/Sleeping Beauty transposase hybrid-vectors. The obtained information will be useful when designing future preclinical studies utilizing hybrid-vectors in small and large animal models.

Efficacy of integrated treatment of UV light and low dose gamma irradiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes

Science.gov (United States)

Efficacy of integrated treatment of UVC and low dose Gamma irradiation to inactivate mixed Strains of Escherichia coli O157:H7 and Salmonella enterica inoculated on whole Grape tomatoes was evaluated. A mixed bacterial cocktail composed of a three strain mixture of E. coli O157:H7 (C9490, E02128 an...

Comparison of dose length, area, and volume histograms as quantifiers of urethral dose in prostate brachytherapy

International Nuclear Information System (INIS)

Butler, Wayne M.; Merrick, Gregory S.; Dorsey, Anthony T.; Hagedorn, Brenda M.

2000-01-01

Purpose: To determine the magnitude of the differences between urethral dose-volume, dose-area, and dose-length histograms (DVH, DAH, and DLH, respectively, or DgH generically). Methods and Materials: Six consecutive iodine-125 ( 125 I) patients and 6 consecutive palladium-103 ( 103 Pd) patients implanted via a modified uniform planning approach were evaluated with day 0 computed tomography (CT)-based dosimetry. The urethra was identified by the presence of a urinary catheter and was hand drawn on the CT images with a mean radius of 3.3 ± 0.7 mm. A 0.1-mm calculation matrix was employed for the urethral volume and surface analysis, and urethral dose points were placed at the centroid of the urethra on each 5-mm CT slice. Results: Although individual patient DLHs were step-like, due to the sparseness of the data points, the composite urethral DLH, DAH, and DVHs were qualitatively similar. The DAH curve delivered more radiation than the other two curves at all doses greater than 90% of the prescribed minimum peripheral dose (mPD) to the prostate. In addition, the DVH curve was consistently higher than the DLH curve at most points throughout that range. Differences between the DgH curves were analyzed by integrating the difference curves between 0 and 200% of the mPD. The area-length, area-volume, and volume-length difference curves integrated in the ratio of 3:2:1. The differences were most pronounced near the inflection point of the DgH curves with mean A 125 , V 125 , and L 125 values of 36.6%, 31.4%, and 23.0%, respectively, of the urethra. Quantifiers of urethral hot spots such as D 10 , defined as the minimal dose delivered to the hottest 10% of the urethra, followed the same ranking: area analysis indicated the highest dose and length analysis, the lowest dose. D 10 was 148% and 136% of mPD for area and length evaluations, respectively. Comparing the two isotopes in terms of the amount of urethra receiving a given dose, 103 Pd implants were significantly

An updated dose assessment for Rongelap Island

Energy Technology Data Exchange (ETDEWEB)

Robison, W.L.; Conrado, C.L.; Bogen, K.T.

1994-07-01

We have updated the radiological dose assessment for Rongelap Island at Rongelap Atoll using data generated from field trips to the atoll during 1986 through 1993. The data base used for this dose assessment is ten fold greater than that available for the 1982 assessment. Details of each data base are presented along with details about the methods used to calculate the dose from each exposure pathway. The doses are calculated for a resettlement date of January 1, 1995. The maximum annual effective dose is 0.26 mSv y{sup {minus}1} (26 mrem y{sup {minus}1}). The estimated 30-, 50-, and 70-y integral effective doses are 0.0059 Sv (0.59 rem), 0.0082 Sv (0.82 rem), and 0.0097 Sv (0.97 rem), respectively. More than 95% of these estimated doses are due to 137-Cesium ({sup 137}Cs). About 1.5% of the estimated dose is contributed by 90-Strontium ({sup 90}Sr), and about the same amount each by 239+240-Plutonium ({sup 239+240}PU), and 241-Americium ({sup 241}Am).

Calculation of integrated biological response in brachytherapy

International Nuclear Information System (INIS)

Dale, Roger G.; Coles, Ian P.; Deehan, Charles; O'Donoghue, Joseph A.

1997-01-01

Purpose: To present analytical methods for calculating or estimating the integrated biological response in brachytherapy applications, and which allow for the presence of dose gradients. Methods and Materials: The approach uses linear-quadratic (LQ) formulations to identify an equivalent biologically effective dose (BED eq ) which, if applied to a specified tissue volume, would produce the same biological effect as that achieved by a given brachytherapy application. For simple geometrical cases, BED multiplying factors have been derived which allow the equivalent BED for tumors to be estimated from a single BED value calculated at a dose reference point. For more complex brachytherapy applications a voxel-by-voxel determination of the equivalent BED will be more accurate. Equations are derived which when incorporated into brachytherapy software would facilitate such a process. Results: At both high and low dose rates, the BEDs calculated at the dose reference point are shown to be lower than the true values by an amount which depends primarily on the magnitude of the prescribed dose; the BED multiplying factors are higher for smaller prescribed doses. The multiplying factors are less dependent on the assumed radiobiological parameters. In most clinical applications involving multiple sources, particularly those in multiplanar arrays, the multiplying factors are likely to be smaller than those derived here for single sources. The overall suggestion is that the radiobiological consequences of dose gradients in well-designed brachytherapy treatments, although important, may be less significant than is sometimes supposed. The modeling exercise also demonstrates that the integrated biological effect associated with fractionated high-dose-rate (FHDR) brachytherapy will usually be different from that for an 'equivalent' continuous low-dose-rate (CLDR) regime. For practical FHDR regimes involving relatively small numbers of fractions, the integrated biological effect to

Technical Note: A direct ray-tracing method to compute integral depth dose in pencil beam proton radiography with a multilayer ionization chamber.

Science.gov (United States)

Farace, Paolo; Righetto, Roberto; Deffet, Sylvain; Meijers, Arturs; Vander Stappen, Francois

2016-12-01

To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45 × 45 mm 2 field-of-view) of 9 × 9 spots capable of crossing the phantoms (210 MeV). The exit beam was collected by a MLIC to sample the integral depth dose (IDD MLIC ). PRs of an electron-density and of a head phantom were acquired by moving the couch to obtain multiple 45 × 45 mm 2 frames. To map the corresponding range errors, the two-dimensional set of IDD MLIC was compared with (i) the integral depth dose computed by the treatment planning system (TPS) by both analytic (IDD TPS ) and Monte Carlo (IDD MC ) algorithms in a volume of water simulating the MLIC at the CT, and (ii) the integral depth dose directly computed by a simple ray-tracing algorithm (IDD direct ) through the same CT data. The exact spatial position of the spot pattern was numerically adjusted testing different in-plane positions and selecting the one that minimized the range differences between IDD direct and IDD MLIC . Range error mapping was feasible by both the TPS and the ray-tracing methods, but very sensitive to even small misalignments. In homogeneous regions, the range errors computed by the direct ray-tracing algorithm matched the results obtained by both the analytic and the Monte Carlo algorithms. In both phantoms, lateral heterogeneities were better modeled by the ray-tracing and the Monte Carlo algorithms than by the analytic TPS computation. Accordingly, when the pencil beam crossed lateral heterogeneities, the range errors mapped by the direct algorithm matched better the Monte Carlo maps than those obtained by the analytic algorithm. Finally, the simplicity of the ray-tracing algorithm allowed to implement a prototype procedure for automated spatial alignment. The ray-tracing algorithm can reliably replace the TPS method in MLIC PR for in

Helical Tomotherapy for Whole-Brain Irradiation With Integrated Boost to Multiple Brain Metastases: Evaluation of Dose Distribution Characteristics and Comparison With Alternative Techniques

International Nuclear Information System (INIS)

Levegrün, Sabine; Pöttgen, Christoph; Wittig, Andrea; Lübcke, Wolfgang; Abu Jawad, Jehad; Stuschke, Martin

2013-01-01

Purpose: To quantitatively evaluate dose distribution characteristics achieved with helical tomotherapy (HT) for whole-brain irradiation (WBRT) with integrated boost (IB) to multiple brain metastases in comparison with alternative techniques. Methods and Materials: Dose distributions for 23 patients with 81 metastases treated with WBRT (30 Gy/10 fractions) and IB (50 Gy) were analyzed. The median number of metastases per patient (N mets ) was 3 (range, 2-8). Mean values of the composite planning target volume of all metastases per patient (PTV mets ) and of the individual metastasis planning target volume (PTV ind met ) were 8.7 ± 8.9 cm 3 (range, 1.3-35.5 cm 3 ) and 2.5 ± 4.5 cm 3 (range, 0.19-24.7 cm 3 ), respectively. Dose distributions in PTV mets and PTV ind met were evaluated with respect to dose conformity (conformation number [CN], RTOG conformity index [PITV]), target coverage (TC), and homogeneity (homogeneity index [HI], ratio of maximum dose to prescription dose [MDPD]). The dependence of dose conformity on target size and N mets was investigated. The dose distribution characteristics were benchmarked against alternative irradiation techniques identified in a systematic literature review. Results: Mean ± standard deviation of dose distribution characteristics derived for PTV mets amounted to CN = 0.790 ± 0.101, PITV = 1.161 ± 0.154, TC = 0.95 ± 0.01, HI = 0.142 ± 0.022, and MDPD = 1.147 ± 0.029, respectively, demonstrating high dose conformity with acceptable homogeneity. Corresponding numbers for PTV ind met were CN = 0.708 ± 0.128, PITV = 1.174 ± 0.237, TC = 0.90 ± 0.10, HI = 0.140 ± 0.027, and MDPD = 1.129 ± 0.030, respectively. The target size had a statistically significant influence on dose conformity to PTV mets (CN = 0.737 for PTV mets ≤4.32 cm 3 vs CN = 0.848 for PTV mets >4.32 cm 3 , P=.006), in contrast to N mets . The achieved dose conformity to PTV mets , assessed by both CN and PITV, was in all investigated volume strata

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

Absorbed dose to the patient by computerized whole body X-ray tomography

International Nuclear Information System (INIS)

Krauss, O.; Schuhmacher, H.

1977-01-01

The absorbed dose to the patient was measured for several medical investigations by computerized whole body scanning. An Alderson-phantom mounted with LiF-TLD was irradiated with a Delta-Scan (Ohio-Nuclear, 120 kV, 30 mA). The integral dose to the brain during a full examination (6 scans, filtration 3 mm Al) was measured to 5x10 -2 J. The maximum absorbed dose at the entrance was found to be 3.2 rd and at the exit 0.6 rd. The dose to the eyes is 0.7 rd and to the thyroid gland 0.03 rd. The integral dose to the trunk (5 scans in the region of liver and kidneys, filtration 6 mm Al) was measured to 5x10 -2 J. The maximum absorbed dose at the entrance was found to be 2.4 rd and at the exit 0.25 rd. The dose to the gonads is less than 2 and 4 mrd if the distance between the last scan and the gonads is more than 15 cm

Use of cadmium sulphide to measure integrated dose in short-time irradiation

International Nuclear Information System (INIS)

Nimnual, S.

1975-01-01

An experiment was made to measure the dose from a short burst of X-rays in the order of 1 second or less by means of the cadmium sulphide photoconductive cell. If protected from light, the CdS cell has a very high resistance such that it does not discharge a capacitor appreciably. But during irradiation, the resistance decreases temporarily and an amount of charge will leak from the capacitor through the Ca S cell. The result to this experiment shows that the principle works very well but it is necessary to add another fixed high resistance of about 10 7 ohms into the circuit in order to get results independent of the dose-rate. The equipment used in this experiment can measure a dose as low as 6 m R

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT studies for the diagnosis of uterine cancer recurrence

Energy Technology Data Exchange (ETDEWEB)

Kitajima, Kazuhiro [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Suzuki, Kayo [Institute of Biomedical Research and Innovation, Department of PET Diagnosis, Kobe (Japan); Nakamoto, Yuji [Kyoto University Hospital, Department of Diagnostic Radiology, Kyoto (Japan); Onishi, Yumiko; Sakamoto, Setsu; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Department of Radiology, Kobe (Japan); Senda, Michio [Institute of Biomedical Research and Innovation, Department of Molecular Imaging, Kobe (Japan); Kita, Masato [Kobe City Medical Center General Hospital, Department of Obstetrics and Gynecology, Kobe (Japan)

2010-08-15

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated {sup 18}F-fluorodeoxyglucose (FDG) PET/CT studies for restaging of uterine cancer. A group of 100 women who had undergone treatment for uterine cervical (n=55) or endometrial cancer (n=45) underwent a conventional PET/CT scans with ldCT, and then a ceCT scan. Two observers retrospectively reviewed and interpreted the PET/ldCT and PET/ceCT images in consensus using a three-point grading scale (negative, equivocal, or positive) per patient and per lesion. Final diagnoses were obtained by histopathological examination, or clinical follow-up for at least 6 months. Patient-based analysis showed that the sensitivity, specificity and accuracy of PET/ceCT were 90% (27/30), 97% (68/70) and 95% (95/100), respectively, whereas those of PET/ldCT were 83% (25/30), 94% (66/70) and 91% (91/100), respectively. Sensitivity, specificity and accuracy did not significantly differ between two methods (McNemar test, p=0.48, p=0.48, and p=0.13, respectively). There were 52 sites of lesion recurrence: 12 pelvic lymph node (LN), 11 local recurrence, 8 peritoneum, 7 abdominal LN, 5 lung, 3 supraclavicular LN, 3 liver, 2 mediastinal LN, and 1 muscle and bone. The grading results for the 52 sites of recurrence were: negative 5, equivocal 0 and positive 47 for PET/ceCT, and negative 5, equivocal 4 and positive 43 for PET/ldCT, respectively. Four equivocal regions by PET/ldCT (local recurrence, pelvic LN metastasis, liver metastasis and muscle metastasis) were correctly interpreted as positive by PET/ceCT. PET/ceCT is an accurate imaging modality for the assessment of uterine cancer recurrence. Its use reduces the frequency of equivocal interpretations. (orig.)

Identification of molecular candidates and interaction networks via integrative toxicogenomic analysis in a human cell line following low-dose exposure to the carcinogenic metals cadmium and nickel.

Science.gov (United States)

Kwon, Jee Young; Weon, Jong-Il; Koedrith, Preeyaporn; Park, Kang-Sik; Kim, Im Soon; Seo, Young Rok

2013-09-01

Cadmium and nickel have been classified as carcinogenic to humans by the World Health Organization's International Agency for Research on Cancer. Given their prevalence in the environment, the fact that cadmium and nickel may cause diseases including cancer even at low doses is a cause for concern. However, the exact mechanisms underlying the toxicological effects induced by low-dose exposure to cadmium and nickel remain to be elucidated. Furthermore, it has recently been recognized that integrative analysis of DNA, mRNA and proteins is required to discover biomarkers and signaling networks relevant to human toxicant exposure. In the present study, we examined the deleterious effects of chronic low-dose exposure of either cadmium or nickel on global profiling of DNA copy number variation, mRNA and proteins. Array comparative genomic hybridization, gene expression microarray and functional proteomics were conducted, and a bioinformatics tool, which predicted signaling pathways, was applied to integrate data for each heavy metal separately and together. We found distinctive signaling networks associated with subchronic low-dose exposure to cadmium and nickel, and identified pathways common to both. ACTB, HSP90AA1, HSPA5 and HSPA8, which are key mediators of pathways related to apoptosis, proliferation and neoplastic processes, were key mediators of the same pathways in low-dose nickel and cadmium exposure in particular. CASP-associated signaling pathways involving CASP3, CASP7 and CASP9 were observed in cadmium-exposed cells. We found that HSP90AA1, one of the main modulators, interacted with HIF1A, AR and BCL2 in nickel-exposed cells. Interestingly, we found that HSP90AA1 was involved in the BCL2-associated apoptotic pathway in the nickel-only data, whereas this gene interacted with several genes functioning in CASP-associated apoptotic signaling in the cadmium-only data. Additionally, JUN and FASN were main modulators in nickel-responsive signaling pathways. Our

The National Dose Registration and Information System: Dose distributions in the Netherlands over the period 1989-1993

International Nuclear Information System (INIS)

Dijk, J.W.E. van; Julius, H.W.; Bogaerde, M.A. van de

1994-01-01

In 1988 the Ministry of Social Affairs and Employment commissioned TNO Radiological Service to set up a National Dose REgistration and Information System (NDRIS). The government had three reasons in view to build NDRIS: To improve radiation protection by supervising the occupational doses of radiation workers by using one central database system; To improve the reliability of long term storage of dose data; To improve the possibilities for statistical analysis of occupational doses to guide policy making. Each approved dosimetry service (ADS) in the country sends its dose information to NDRIS on a monthly basis. IN its turn NDRIS sends back for each worker monitored by that ADS, the integrated dose as measured by any ADS. This creates the possibility for each ADS to report to the workers their total annual dose irrespectively whether they work for more than one employer or are monitored by more than one ADS, either simultaneously or successively in the course of the year. European legislation requires that the occupational dose should be controlled in this way. The availability of the centralized database replaces the need of a radiation passbook for national use. The passbook that is needed by radiation workers during interstate travelling can be produced using data from NDRIS

Assessment of internal doses

CERN Document Server

Rahola, T; Falk, R; Isaksson, M; Skuterud, L

2002-01-01

There is a definite need for training in dose calculation. Our first course was successful and was followed by a second, both courses were fully booked. An example of new tools for software products for bioassay analysis and internal dose assessment is the Integrated Modules for Bioassay Analysis (IMBA) were demonstrated at the second course. This suite of quality assured code modules have been adopted in the UK as the standard for regulatory assessment purposes. The intercomparison measurements are an important part of the Quality Assurance work. In what is known as the sup O utside workers ' directive it is stated that the internal dose measurements shall be included in the European Unions supervision system for radiation protection. The emergency preparedness regarding internal contamination was much improved by the training with and calibration of handheld instruments from participants' laboratories. More improvement will be gained with the handbook giving practical instructions on what to do in case of e...

Pediatric radiation dose management in digital radiography

International Nuclear Information System (INIS)

Neitzel, U.

2004-01-01

Direct digital radiography (DR) systems based on flat-panel detectors offer improved dose management in pediatric radiography. Integration of X-ray generation and detection in one computer-controlled system provides better control and monitoring

A conceptual framework for managing radiation dose to patients in diagnostic radiology using reference dose levels

International Nuclear Information System (INIS)

Almen, Anja; Baath, Magnus

2016-01-01

The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. (authors)

SU-F-T-329: Characteristic Study of a Rado-Photoluminescenct Glass Dosimeter with Accumulated Dose

Energy Technology Data Exchange (ETDEWEB)

Kim, D; Chung, W; Chung, M [Kyung Hee University Hospital at Gangdong, Gangdong-gu (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

2016-06-15

Purpose: This study investigated the effect of accumulated dose on radiophotoluminescent glass dosimeter in megavoltage photon. Methods: 45 commercially-available radio-photoluminescence glass dosimeters (RPLGD; GD-302M, Asahi Techno Glass Co., Shizuoka, JAPAN) were irradiated to 10 × 10 cm{sup 2} open-field with 6, 10 and 15 MV photon beams at 100 cm of source to surface distance and dose maximum depths. Each energy has consists of five groups which is consists of three detectors. A group #1 and #2 was irradiated about 1 Gy to 100 Gy, and estimated the integral dose response with and without annealing procedure. A group #3 was read the dose after irradiated 10 Gy of dose by 10 times repeatedly to estimate the fading effect of RPLGD. A group #4 and #5 was produced same ways with different irradiation dose such as 50 Gy for group #4 and 100 Gy for group #5. Results: From the results of group #1 and #2, an annealed detector shows linear response to integral dose but other detectors without the annealing process, has supra linearity for integral dose especially close to 100 Gy dose. For group #3, #4 and #5, the dose response of repeated irradiation, the dose response was decreased about 15%, 12% and 7% for 6 MV, 10 MV and 15MV. Conclusion: It was found that RPLGD response to accumulated dose was supra linear and this respond was altered with amount of accumulated dose to the RPLGD. In addition, the fading effect need to be concern with RPLGD.

A dose monitoring system for dental radiography

Energy Technology Data Exchange (ETDEWEB)

Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Symkhampha, Khanthaly [Dept. of Oral and Maxillofacial Radiology, Department of Basic Science, Faculty of Dentistry, University of Health Sciences, Vientiane (Lao People' s Democratic Republic); Lee, Woo Jin [Dept. of Interdisciplinary Program in Radiation, Applied Life Sciences Major, College of Medicine, BK21, and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Yeom, Heon Young [School of Computer Science Engineering, Seoul National University, Seoul (Korea, Republic of)

2016-06-15

The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.

A dose monitoring system for dental radiography

International Nuclear Information System (INIS)

Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul; Symkhampha, Khanthaly; Lee, Woo Jin; Yeom, Heon Young

2016-01-01

The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose

Analysis of a Statistical Relationship Between Dose and Error Tallies in Semiconductor Digital Integrated Circuits for Application to Radiation Monitoring Over a Wireless Sensor Network

Science.gov (United States)

Colins, Karen; Li, Liqian; Liu, Yu

2017-05-01

Mass production of widely used semiconductor digital integrated circuits (ICs) has lowered unit costs to the level of ordinary daily consumables of a few dollars. It is therefore reasonable to contemplate the idea of an engineered system that consumes unshielded low-cost ICs for the purpose of measuring gamma radiation dose. Underlying the idea is the premise of a measurable correlation between an observable property of ICs and radiation dose. Accumulation of radiation-damage-induced state changes or error events is such a property. If correct, the premise could make possible low-cost wide-area radiation dose measurement systems, instantiated as wireless sensor networks (WSNs) with unshielded consumable ICs as nodes, communicating error events to a remote base station. The premise has been investigated quantitatively for the first time in laboratory experiments and related analyses performed at the Canadian Nuclear Laboratories. State changes or error events were recorded in real time during irradiation of samples of ICs of different types in a 60Co gamma cell. From the error-event sequences, empirical distribution functions of dose were generated. The distribution functions were inverted and probabilities scaled by total error events, to yield plots of the relationship between dose and error tallies. Positive correlation was observed, and discrete functional dependence of dose quantiles on error tallies was measured, demonstrating the correctness of the premise. The idea of an engineered system that consumes unshielded low-cost ICs in a WSN, for the purpose of measuring gamma radiation dose over wide areas, is therefore tenable.

SIGMA/B, Doses in Space Vehicle for Multiple Trajectories, Various Radiation Source

International Nuclear Information System (INIS)

Jordan, T.M.

2003-01-01

1 - Description of problem or function: SIGMA/B calculates radiation dose at arbitrary points inside a space vehicle, taking into account vehicle geometry, heterogeneous placement of equipment and stores, vehicle materials, time-weighted astronaut positions and many radiation sources from mission trajectories, e.g. geomagnetically trapped protons and electrons, solar flare particles, galactic cosmic rays and their secondary radiations. The vehicle geometry, equipment and supplies, and man models are described by quadric surfaces. The irradiating flux field may be anisotropic. The code can be used to perform simultaneous dose calculations for multiple vehicle trajectories, each involving several radiation sources. Results are presented either as dose as a function of shield thickness, or the dose received through designated outer sections of the vehicle. 2 - Method of solution: Automatic sectoring of the vehicle is performed by a Simpson's rule integration over angle; the dose is computed by a numerical angular integration of the dose attenuation kernels about the dose points. The kernels are curve-fit functions constructed from input data tables. 3 - Restrictions on the complexity of the problem: The code uses variable dimensioning techniques to store data. The only restriction on problem size is the available core storage

A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

Science.gov (United States)

Almén, Anja; Båth, Magnus

2016-06-01

The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

VirtualDose: a software for reporting organ doses from CT for adult and pediatric patients

Science.gov (United States)

Ding, Aiping; Gao, Yiming; Liu, Haikuan; Caracappa, Peter F.; Long, Daniel J.; Bolch, Wesley E.; Liu, Bob; Xu, X. George

2015-07-01

This paper describes the development and testing of VirtualDose—a software for reporting organ doses for adult and pediatric patients who undergo x-ray computed tomography (CT) examinations. The software is based on a comprehensive database of organ doses derived from Monte Carlo (MC) simulations involving a library of 25 anatomically realistic phantoms that represent patients of different ages, body sizes, body masses, and pregnant stages. Models of GE Lightspeed Pro 16 and Siemens SOMATOM Sensation 16 scanners were carefully validated for use in MC dose calculations. The software framework is designed with the ‘software as a service (SaaS)’ delivery concept under which multiple clients can access the web-based interface simultaneously from any computer without having to install software locally. The RESTful web service API also allows a third-party picture archiving and communication system software package to seamlessly integrate with VirtualDose’s functions. Software testing showed that VirtualDose was compatible with numerous operating systems including Windows, Linux, Apple OS X, and mobile and portable devices. The organ doses from VirtualDose were compared against those reported by CT-Expo and ImPACT—two dosimetry tools that were based on the stylized pediatric and adult patient models that were known to be anatomically simple. The organ doses reported by VirtualDose differed from those reported by CT-Expo and ImPACT by as much as 300% in some of the patient models. These results confirm the conclusion from past studies that differences in anatomical realism offered by stylized and voxel phantoms have caused significant discrepancies in CT dose estimations.

VirtualDose: a software for reporting organ doses from CT for adult and pediatric patients

International Nuclear Information System (INIS)

Ding, Aiping; Gao, Yiming; Liu, Haikuan; Caracappa, Peter F; Xu, X George; Long, Daniel J; Bolch, Wesley E; Liu, Bob

2015-01-01

This paper describes the development and testing of VirtualDose—a software for reporting organ doses for adult and pediatric patients who undergo x-ray computed tomography (CT) examinations. The software is based on a comprehensive database of organ doses derived from Monte Carlo (MC) simulations involving a library of 25 anatomically realistic phantoms that represent patients of different ages, body sizes, body masses, and pregnant stages. Models of GE Lightspeed Pro 16 and Siemens SOMATOM Sensation 16 scanners were carefully validated for use in MC dose calculations. The software framework is designed with the ‘software as a service (SaaS)’ delivery concept under which multiple clients can access the web-based interface simultaneously from any computer without having to install software locally. The RESTful web service API also allows a third-party picture archiving and communication system software package to seamlessly integrate with VirtualDose’s functions. Software testing showed that VirtualDose was compatible with numerous operating systems including Windows, Linux, Apple OS X, and mobile and portable devices. The organ doses from VirtualDose were compared against those reported by CT-Expo and ImPACT—two dosimetry tools that were based on the stylized pediatric and adult patient models that were known to be anatomically simple. The organ doses reported by VirtualDose differed from those reported by CT-Expo and ImPACT by as much as 300% in some of the patient models. These results confirm the conclusion from past studies that differences in anatomical realism offered by stylized and voxel phantoms have caused significant discrepancies in CT dose estimations. (paper)

Hyperfractionated accelerated radiotherapy with concomitant integrated boost of 70-75 Gy in 5 weeks for advanced head and neck cancer. A phase I dose escalation study

Energy Technology Data Exchange (ETDEWEB)

Cvek, J.; Skacelikova, E.; Otahal, B.; Halamka, M.; Feltl, D. [University Hospital Ostrava (Czech Republic). Dept. of Oncology; Kubes, J. [University Hospital Bulovka, Prague (Czech Republic). Dept. of Radiation Oncology; Kominek, P. [University Hospital Ostrava (Czech Republic). Dept. of Otolaryngology

2012-08-15

Background and purpose: The present study was performed to evaluate the feasibility of a new, 5-week regimen of 70-75 Gy hyperfractionated accelerated radiotherapy with concomitant integrated boost (HARTCIB) for locally advanced, inoperable head and neck cancer. Methods and materials: A total of 39 patients with very advanced, stage IV nonmetastatic head and neck squamous cell carcinoma (median gross tumor volume 72 ml) were included in this phase I dose escalation study. A total of 50 fractions intensity-modulated radiotherapy (IMRT) were administered twice daily over 5 weeks. Prescribed total dose/dose per fraction for planning target volume (PTV{sub tumor}) were 70 Gy in 1.4 Gy fractions, 72.5 Gy in 1.45 Gy fractions, and 75 Gy in 1.5 Gy fractions for 10, 13, and 16 patients, respectively. Uninvolved lymphatic nodes (PTV{sub uninvolved}) were irradiated with 55 Gy in 1.1 Gy fractions using the concomitant integrated boost. Results: Acute toxicity was evaluated according to the RTOG/EORTC scale; the incidence of grade 3 mucositis was 51% in the oral cavity/pharynx and 0% in skin and the recovery time was {<=} 9 weeks for all patients. Late toxicity was evaluated in patients in complete remission according to the RTOG/EORTC scale. No grade 3/4 late toxicity was observed. The 1-year locoregional progression-free survival was 50% and overall survival was 55%. Conclusion: HARTCIB (75 Gy in 5 weeks) is feasible for patients deemed unsuitable for chemoradiation. Acute toxicity was lower than predicted from radiobiological models; duration of dysphagia and confluent mucositis were particularly short. Better conformity of radiotherapy allows the use of more intensive altered fractionation schedules compared with older studies. These results suggest that further dose escalation might be possible when highly conformal techniques (e.g., stereotactic radiotherapy) are used.

Dose point kernels for beta-emitting radioisotopes

International Nuclear Information System (INIS)

Prestwich, W.V.; Chan, L.B.; Kwok, C.S.; Wilson, B.

1986-01-01

Knowledge of the dose point kernel corresponding to a specific radionuclide is required to calculate the spatial dose distribution produced in a homogeneous medium by a distributed source. Dose point kernels for commonly used radionuclides have been calculated previously using as a basis monoenergetic dose point kernels derived by numerical integration of a model transport equation. The treatment neglects fluctuations in energy deposition, an effect which has been later incorporated in dose point kernels calculated using Monte Carlo methods. This work describes new calculations of dose point kernels using the Monte Carlo results as a basis. An analytic representation of the monoenergetic dose point kernels has been developed. This provides a convenient method both for calculating the dose point kernel associated with a given beta spectrum and for incorporating the effect of internal conversion. An algebraic expression for allowed beta spectra has been accomplished through an extension of the Bethe-Bacher approximation, and tested against the exact expression. Simplified expression for first-forbidden shape factors have also been developed. A comparison of the calculated dose point kernel for 32 P with experimental data indicates good agreement with a significant improvement over the earlier results in this respect. An analytic representation of the dose point kernel associated with the spectrum of a single beta group has been formulated. 9 references, 16 figures, 3 tables

An integrated logistic formula for prediction of complications from radiosurgery

International Nuclear Information System (INIS)

Flickinger, J.C.

1989-01-01

An integrated logistic model for predicting the probability of complications when small volumes of tissue receive an inhomogeneous radiation dose is described. This model can be used with either an exponential or linear quadratic correction for dose per fraction and time. Both the exponential and linear quadratic versions of this integrated logistic formula provide reasonable estimates of the tolerance of brain to radiosurgical dose distributions where there are small volumes of brain receiving high radiation doses and larger volumes receiving lower doses. This makes it possible to predict the probability of complications from stereotactic radiosurgery, as well as combinations of fractionated large volume irradiation with a radiosurgical boost. Complication probabilities predicted for single fraction radiosurgery with the Leksell Gamma Unit using 4, 8, 14, and 18 mm diameter collimators as well as for whole brain irradiation combined with a radiosurgical boost are presented. The exponential and linear quadratic versions of the integrated logistic formula provide useful methods of calculating the probability of complications from radiosurgical treatment

Calculation of doses received while crossing a plume of radioactive material

International Nuclear Information System (INIS)

Scherpelz, R.I.; Desrosiers, A.E.

1981-04-01

A method has been developed for determining the dose received by a person while crossing a plume of radioactive material. The method uses a Gaussian plume model to arrive at a dose rate on the plume centerline at the position of the plume crossing. This dose rate may be due to any external or internal dose pathway. An algebraic formula can then be used to convert the plume centerline dose rate to a total dose integrated over the total time of plume crossing. Correction factors are presented for dose pathways in which the dose rate is not normally distributed about the plume centerline. The method is illustrated by a study done at the Pacific Northwest Laboratory, and results of this study are presented

Dose rate from the square volume radiation source

International Nuclear Information System (INIS)

Karpov, V.I.

1978-01-01

The expression for determining the dose rate from a three-dimensional square flat-parallel source of any dimensions is obtained. A simplified method for integrating the resultant expression is proposed. A comparison of the calculation results with the results by the Monte Carlo method has shown them to coincide within 6-8%. Since buildings and structures consist of rectangular elements, the method is recommended for practical calculations of dose rates in residential buildings

Real-time electron-beam dose monitoring

International Nuclear Information System (INIS)

McKeown, J.

1995-01-01

A new technique to monitor the integrated dose that a product receives in an irradiation facility is determined by collecting the charge that passes through the product. The technique allows the absorbed dose to be monitored as the irradiation is taking place, i.e. on-line and in real time. The procedure will also provide a means of directly measuring the electron energy, independent of the accelerator control system. The irradiation plant operator can immediately detect a problem of inadequate electron energy and take appropriate action. Examples taken on the IMPELA trademark accelerator at the Iotron Irradiation Facility in Vancouver are presented

Direct dose mapping versus energy/mass transfer mapping for 4D dose accumulation: fundamental differences and dosimetric consequences.

Science.gov (United States)

Li, Haisen S; Zhong, Hualiang; Kim, Jinkoo; Glide-Hurst, Carri; Gulam, Misbah; Nurushev, Teamour S; Chetty, Indrin J

2014-01-06

The direct dose mapping (DDM) and energy/mass transfer (EMT) mapping are two essential algorithms for accumulating the dose from different anatomic phases to the reference phase when there is organ motion or tumor/tissue deformation during the delivery of radiation therapy. DDM is based on interpolation of the dose values from one dose grid to another and thus lacks rigor in defining the dose when there are multiple dose values mapped to one dose voxel in the reference phase due to tissue/tumor deformation. On the other hand, EMT counts the total energy and mass transferred to each voxel in the reference phase and calculates the dose by dividing the energy by mass. Therefore it is based on fundamentally sound physics principles. In this study, we implemented the two algorithms and integrated them within the Eclipse treatment planning system. We then compared the clinical dosimetric difference between the two algorithms for ten lung cancer patients receiving stereotactic radiosurgery treatment, by accumulating the delivered dose to the end-of-exhale (EE) phase. Specifically, the respiratory period was divided into ten phases and the dose to each phase was calculated and mapped to the EE phase and then accumulated. The displacement vector field generated by Demons-based registration of the source and reference images was used to transfer the dose and energy. The DDM and EMT algorithms produced noticeably different cumulative dose in the regions with sharp mass density variations and/or high dose gradients. For the planning target volume (PTV) and internal target volume (ITV) minimum dose, the difference was up to 11% and 4% respectively. This suggests that DDM might not be adequate for obtaining an accurate dose distribution of the cumulative plan, instead, EMT should be considered.

Calculation method for gamma-dose rates from spherical puffs

International Nuclear Information System (INIS)

Thykier-Nielsen, S.; Deme, S.; Lang, E.

1993-05-01

The Lagrangian puff-models are widely used for calculation of the dispersion of atmospheric releases. Basic output from such models are concentrations of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on semi-infinite cloud model. This method is however only applicable for points far away from the release point. The exact calculation of the cloud dose using the volume integral requires significant computer time. The volume integral for the gamma dose could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor due to the fact that the same correction factors are used for all isotopes. The authors describe a more elaborate correction method. This method uses precalculated values of the gamma-dose rate as a function of the puff dispersion parameter (δ p ) and the distance from the puff centre for four energy groups. The release of energy for each radionuclide in each energy group has been calculated and tabulated. Based on these tables and a suitable interpolation procedure the calculation of gamma doses takes very short time and is almost independent of the number of radionuclides. (au) (7 tabs., 7 ills., 12 refs.)

Development of a real-time radiological dose assessment system

Energy Technology Data Exchange (ETDEWEB)

Han, Moon Hee; Lee, Young Bok; Kim, Eun Han; Suh, Kyung Suk; Hwang, Won Tae; Choi, Young Gil

1997-07-01

A radiological dose assessment system named FADAS has been developed. This system is necessary to estimated the radiological consequences against a nuclear accident. Mass-consistent wind field module was adopted for the generation of wind field over the whole domain using the several measured wind data. Random-walk dispersion module is used for the calculation of the distribution of radionuclides in the atmosphere. And volume-equivalent numerical integration method has been developed for the assessment of external gamma exposure given from a randomly distributed radioactive materials and a dose data library has been made for rapid calculation. Field tracer experiments have been carried out for the purpose of analyzing the site-specific meteorological characteristics and increasing the accuracy of wind field generation and atmospheric dispersion module of FADAS. At first, field tracer experiment was carried out over flat terrain covered with rice fields using the gas samplers which were designed and manufactured by the staffs of KAERI. The sampled gas was analyzed using gas chromatograph. SODAR and airsonde were used to measure the upper wind. Korean emergency preparedness system CARE was integrated at Kori 4 nuclear power plants in 1995. One of the main functions of CARE is to estimate the radiological dose. The developed real-time dose assessment system FADAS was adopted in CARE as a tool for the radiological dose assessment. (author). 79 refs., 52 tabs., 94 figs.

Multidisciplinary European Low Dose Initiative (MELODI). Strategic research agenda for low dose radiation risk research

Energy Technology Data Exchange (ETDEWEB)

Kreuzer, M. [Federal Office for Radiation Protection, BfS, Department of Radiation Protection and Health, Neuherberg (Germany); Auvinen, A. [University of Tampere, Tampere (Finland); STUK, Helsinki (Finland); Cardis, E. [ISGlobal, Barcelona Institute for Global Health, Barcelona (Spain); Durante, M. [Institute for Fundamental Physics and Applications, TIFPA, Trento (Italy); Harms-Ringdahl, M. [Stockholm University, Centre for Radiation Protection Research, Stockholm (Sweden); Jourdain, J.R. [Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-aux-roses (France); Madas, B.G. [MTA Centre for Energy Research, Environmental Physics Department, Budapest (Hungary); Ottolenghi, A. [University of Pavia, Physics Department, Pavia (Italy); Pazzaglia, S. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome (Italy); Prise, K.M. [Queens University Belfast, Belfast (United Kingdom); Quintens, R. [Belgian Nuclear Research Centre, SCK-CEN, Mol (Belgium); Sabatier, L. [French Atomic Energy Commission, CEA, Paris (France); Bouffler, S. [Public Health England, PHE, Chilton (United Kingdom)

2018-03-15

MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html). (orig.)

Reassessment of the potential radiological doses for residents resettling Enewetak Atoll

International Nuclear Information System (INIS)

Robison, W.L.; Phillips, W.A.; Mount, M.E.; Clegg, B.R.; Conrado, C.L.

1980-01-01

The purpose of this report is to refine the dose predictions, subsequent to the cleanup effort, for alternate living patterns proposed for resettlement of Enewetak Atoll. The most recent data developed from projects at Enewetak and Bikini Atolls for concentration and uptake of Cs, Sr, Pu, and Am were used in conjunction with recent dietary information and current dose models to predict annual dose rates and 30- and 50-y integral doses (dose commitments). The terrestrial food chain in the most significant exposure pathway - it contributes more than 50% of the total dose - and external gamma exposure is the second most significant pathway. Other pathways evaluated are the marine food chain, drinking water, and inhalation

Radiation dose in mammography: an energy-balance approach

International Nuclear Information System (INIS)

Shrivastava, P.N.

1981-01-01

An energy-balance approach for calculation of mean, integral, and midpoint doses in mammography is introduced. Estimation of mean absorbed dose for individual applications is described. Calculations made for a range of xeromammographic techniques used at various breast cancer detection centers show that although increasing the beam h.v.l. dramatically decreases breast surface exposure, it is insignificant in lowering mean breast dose or radiation risk. Thus selection of a moderate h.v.l. to optimize image quality in xeromammography may be more beneficial than unduly increasing h.v.l. merely to reduce surface exposure. The mean breast dose per mammogram with low h.v.l. screen-film techniques was 3 to 9 times lower than for xeromammography, suggesting that general acceptance of screen-film techniques can significantly reduce the risk associated with mammography

On the sensitivity of IMRT dose optimization to the mathematical form of a biological imaging-based prescription function

International Nuclear Information System (INIS)

Bowen, Stephen R; Bentzen, Soeren M; Jeraj, Robert; Flynn, Ryan T

2009-01-01

Voxel-based prescriptions of deliberately non-uniform dose distributions based on molecular imaging, so-called dose painting or theragnostic radiation therapy, require specification of a transformation that maps the image data intensities to prescribed doses. However, the functional form of this transformation is currently unknown. An investigation into the sensitivity of optimized dose distributions resulting from several possible prescription functions was conducted. Transformations between the radiotracer activity concentrations from Cu-ATSM PET images, as a surrogate of tumour hypoxia, and dose prescriptions were implemented to yield weighted distributions of prescribed dose boosts in high uptake regions. Dose escalation was constrained to reflect clinically realistic whole tumour doses and constant normal tissue doses. Optimized heterogeneous dose distributions were found by minimizing a voxel-by-voxel quadratic objective function in which all tumour voxels were given equal weight. Prescriptions based on a polynomial mapping function were found to be least constraining on their optimized plans, while prescriptions based on a sigmoid mapping function were the most demanding to deliver. A prescription formalism that fixed integral dose was less sensitive to errors in the choice of the mapping function than one that boosted integral dose. Integral doses to normal tissue and critical structures were insensitive to the shape of the prescription function. Planned target dose conformity improved with smaller beamlet dimensions until the inherent spatial resolution of the functional image was matched. Clinical implementation of dose painting depends on advances in absolute quantification of functional images and improvements in delivery techniques over smaller spatial scales.

Calculation method for gamma dose rates from Gaussian puffs

Energy Technology Data Exchange (ETDEWEB)

Thykier-Nielsen, S; Deme, S; Lang, E

1995-06-01

The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E{sub {gamma}}, {sigma}{sub y}, the asymmetry factor - {sigma}{sub y}/{sigma}{sub z}, the height of puff center - H and the distance from puff center R{sub xy}. To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs.

Calculation method for gamma dose rates from Gaussian puffs

International Nuclear Information System (INIS)

Thykier-Nielsen, S.; Deme, S.; Lang, E.

1995-06-01

The Lagrangian puff models are widely used for calculation of the dispersion of releases to the atmosphere. Basic output from such models is concentration of material in the air and on the ground. The most simple method for calculation of the gamma dose from the concentration of airborne activity is based on the semi-infinite cloud model. This method is however only applicable for puffs with large dispersion parameters, i.e. for receptors far away from the release point. The exact calculation of the cloud dose using volume integral requires large computer time usually exceeding what is available for real time calculations. The volume integral for gamma doses could be approximated by using the semi-infinite cloud model combined with correction factors. This type of calculation procedure is very fast, but usually the accuracy is poor because only a few of the relevant parameters are considered. A multi-parameter method for calculation of gamma doses is described here. This method uses precalculated values of the gamma dose rates as a function of E γ , σ y , the asymmetry factor - σ y /σ z , the height of puff center - H and the distance from puff center R xy . To accelerate the calculations the release energy, for each significant radionuclide in each energy group, has been calculated and tabulated. Based on the precalculated values and suitable interpolation procedure the calculation of gamma doses needs only short computing time and it is almost independent of the number of radionuclides considered. (au) 2 tabs., 15 ills., 12 refs

Acute Radiation Risk and BRYNTRN Organ Dose Projection Graphical User Interface

Science.gov (United States)

Cucinotta, Francis A.; Hu, Shaowen; Nounu, Hateni N.; Kim, Myung-Hee

2011-01-01

The integration of human space applications risk projection models of organ dose and acute radiation risk has been a key problem. NASA has developed an organ dose projection model using the BRYNTRN with SUM DOSE computer codes, and a probabilistic model of Acute Radiation Risk (ARR). The codes BRYNTRN and SUM DOSE are a Baryon transport code and an output data processing code, respectively. The risk projection models of organ doses and ARR take the output from BRYNTRN as an input to their calculations. With a graphical user interface (GUI) to handle input and output for BRYNTRN, the response models can be connected easily and correctly to BRYNTRN. A GUI for the ARR and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations, which are required for operations of the ARRBOD modules. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. BRYNTRN code operation requires extensive input preparation. Only a graphical user interface (GUI) can handle input and output for BRYNTRN to the response models easily and correctly. The purpose of the GUI development for ARRBOD is to provide seamless integration of input and output manipulations for the operations of projection modules (BRYNTRN, SLMDOSE, and the ARR probabilistic response model) in assessing the acute risk and the organ doses of significant Solar Particle Events (SPEs). The assessment of astronauts radiation risk from SPE is in support of mission design and operational planning to manage radiation risks in future space missions. The ARRBOD GUI can identify the proper shielding solutions using the gender-specific organ dose assessments in order to avoid ARR symptoms, and to stay within the current NASA short-term dose limits. The quantified evaluation of ARR severities based on any given shielding configuration and a specified EVA or other mission

Integrated Task Plans for the Hanford Environmental Dose Reconstruction Project, FY 1992 through May 1994

International Nuclear Information System (INIS)

Shipler, D.B.

1992-09-01

The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses from Hanford Site operations since 1944 to populations and individuals. The primary objective of work to be performed through May 1994 is to (1) determine the project's appropriate scope (space, time, radionuclides, pathways and individuals/population groups), (2) determine the project's appropriate level of accuracy (level of uncertainty in dose estimates) for the project, (3) complete model and data development, and (4) estimate doses for the Hanford Thyroid Disease Study (HTDS), representative individuals, and special populations as described herein. The plan for FY 1992 through May 1994 has been prepared based on activities and budgets approved by the Technical Steering Panel (TSP) at its meetings on August 19--20, 1991, and April 23--25, 1992. The activities can be divided into four broad categories: (1) model and data evaluation activities, (2)additional dose estimates, (3) model and data development activities, and (4)technical and communication support

Parameters used in the environmental pathways (DESCARTES) and radiological dose (CIDER) modules of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC) for the air pathway. Hanford Environmental Dose Reconstruction Project

Energy Technology Data Exchange (ETDEWEB)

Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

1992-09-01

This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site since 1944. This work is being done by staff at Battelle, Pacific Northwest Laboratories (Battelle) under a contract with the Centers for Disease Control (CDC) with technical direction provided by an independent Technical Steering Panel (TSP). The objective of this report is to-document the environmental accumulation and dose-assessment parameters that will be used to estimate the impacts of past Hanford Site airborne releases. During 1993, dose estimates made by staff at Battelle will be used by the Fred Hutchinson Cancer Research Center as part of the Hanford Thyroid Disease Study (HTDS). This document contains information on parameters that are specific to the airborne release of the radionuclide iodine-131. Future versions of this document will include parameter information pertinent to other pathways and radionuclides.

An independent dose calculation algorithm for MLC-based stereotactic radiotherapy

International Nuclear Information System (INIS)

Lorenz, Friedlieb; Killoran, Joseph H.; Wenz, Frederik; Zygmanski, Piotr

2007-01-01

We have developed an algorithm to calculate dose in a homogeneous phantom for radiotherapy fields defined by multi-leaf collimator (MLC) for both static and dynamic MLC delivery. The algorithm was developed to supplement the dose algorithms of the commercial treatment planning systems (TPS). The motivation for this work is to provide an independent dose calculation primarily for quality assurance (QA) and secondarily for the development of static MLC field based inverse planning. The dose calculation utilizes a pencil-beam kernel. However, an explicit analytical integration results in a closed form for rectangular-shaped beamlets, defined by single leaf pairs. This approach reduces spatial integration to summation, and leads to a simple method of determination of model parameters. The total dose for any static or dynamic MLC field is obtained by summing over all individual rectangles from each segment which offers faster speed to calculate two-dimensional dose distributions at any depth in the phantom. Standard beam data used in the commissioning of the TPS was used as input data for the algorithm. The calculated results were compared with the TPS and measurements for static and dynamic MLC. The agreement was very good (<2.5%) for all tested cases except for very small static MLC sizes of 0.6 cmx0.6 cm (<6%) and some ion chamber measurements in a high gradient region (<4.4%). This finding enables us to use the algorithm for routine QA as well as for research developments

Exposure subpopulations and peculiarities of individual dose distributions among inhabitants of the Semipalatinsk region

Energy Technology Data Exchange (ETDEWEB)

Pivovarov, S. [Institute of Nuclear Physics, National Nuclear Center of Kazakhstan (Kazakhstan)], E-mail: pivov@inp.kz; Rukhin, A.; Seredavina, T.; Sushkova, N. [Institute of Nuclear Physics, National Nuclear Center of Kazakhstan (Kazakhstan); Hill, P. [Forschungszentrum GmbH, Department of Safety and Radiation Protection, Juelich (Germany)], E-mail: p.hill@fz-juelich.de; Peterson, L.E. [Baylor College of Medicine, Houston, TX (United States)], E-mail: peterson.leif@ieee.org

2007-07-15

The results of integral dose estimations for inhabitants of four settlements near the former Semipalatinsk nuclear test site obtained by EPR dosimetry on tooth enamel in 2004-2005 years are discussed. It was found that the observed dose distributions have a nonstandard bimodal form with a mode at low doses in the range from 0.3-0.5 Gy, and a tail with higher doses, possibly suggesting two subpopulations. Possible reasons for such high doses are discussed.

Standardized evaluation of simultaneous integrated boost plans on volumetric modulated arc therapy

International Nuclear Information System (INIS)

Yang Wensha; Jones, Ryan; Read, Paul; Benedict, Stanley; Sheng Ke

2011-01-01

The purpose of this paper is to quantify the capability of the RapidArc (RA) planning system to deliver highly heterogeneous doses for simultaneous integrated boost (SIB) in both a phantom and patients. A cylindrical planning target volume (PTV) with a diameter of 6 cm was created in a cylindrical phantom. A smaller boost tumor volume (BTV) in the PTV with varying diameters (0.625-2.5 cm), positions and shapes was also created. Five previously treated patients with brain tumors were included in the study. Original gross tumor volumes (average 41.8 cm 3 ) and PTVs (average 316 cm 3 ) were adopted as the BTV and the PTV in the new plans. 30 Gy was prescribed to the PTV. Doses varying from 35 to 90 Gy were prescribed to the BTV. Both SIB and sequential boost (SEQ) plans were created on RA to meet the prescription. A set of reference plans was also created on the helical tomotherapy (HT) platform. Normalized dose contrast (NDC) and the integral dose were used to evaluate the quality of plans. NDC was defined as the dose contrast between BTV and PTV-BTV, normalizing to the ideal scenario where the contrast is the ratio between prescribed doses to the BTV and PTV. NDC above 90% was observed with BTV dose less than 60 Gy. NDC was minimally affected by the size of BTV but adversely affected by the complexity of the shape of the BTV. In the phantom plans, a peak of NDC was observed with 45 Gy (150% of PTV dose) to the BTV; for BTVs at the center of the PTV, the increase in the integral dose was less than 2% and remained constant for all dose levels in the phantom plans but a linear increase in the integral dose was observed with the HT plans. In the patient plans, an 11% average increase in the integral dose was observed with SIB plans and 60 Gy to the BTV, lower than the 30% average increase in the SEQ plans by RA and 25% by HT. The study showed not only that SIB by RA can achieve superior plans compared with SEQ plans on the same platform and SIB plans on HT, but also the

Integrated task plans for the Hanford Environmental Dose Reconstruction Project, June 1992 through May 1994

International Nuclear Information System (INIS)

Shipler, D.B.

1993-09-01

The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate radiation doses from Hanford Site operations since 1944 to representative individuals. The primary objective of work to be performed through May 1994 is to determine the project's appropriate scope: space, time, radionuclides, pathways and representative individuals; determine the project's appropriate level of accuracy/level of uncertainty in dose estimates; complete model and data development; and estimate doses for the Hanford Thyroid Disease Study and representative individuals. A major objective of the HEDR Project is to estimate doses to the thyroid of individuals who were exposed to iodine-131. A principal pathway for many of these individuals was milk from cows that ate vegetation contaminated by iodine-131 released into the air from Hanford facilities. The plan for June 1992 through May 1994 has been prepared based on activities and budgets approved by the Technical Steering Panel (TSP) at its meetings on January 7--9, 1993 and February 25--26, 1993. The activities can be divided into three broad categories: (1) computer code and data development activities, (2) calculation of doses, and (3) technical and communication support to the TSP and the TSP Native American Working Group (NAWG). The following activities will be conducted to accomplish project objectives through May 1994

Global Collective Dose Commitments from Release of Long-Lived Radionuclides

DEFF Research Database (Denmark)

Gjørup, H. L.

1977-01-01

The concept of global collective dose commitment as a measure of total detriment from the release of radioactivity to the environment is outlined. Estimates are given of global collective dose commitments resulting from the release of 14C and uranium daughter products from the nuclear fuel cycle...... that the use of global collective dose commitments in differential cost-benefit analysis can lead to questionable results. In differential cost-benefit analysis it is suggested that population exposures should not simply be integrated irrespective of their time of occurrence, but that a certain discount rate...

Integrated nutrients management for 'desi' cotton

International Nuclear Information System (INIS)

Qazi, M.A.; Akram, M.; Ahmad, N.; Khattak, M.A.

2007-01-01

Intensive cropping with no return of crop residues and other organic inputs result in the loss of soil organic matter (SOM) and nutrient supply in (Desi) cotton-wheat cropping system in Pakistan. For appraisal of problem and finding solution to sustainability, we evaluated six treatments comprised of two fertilizer doses and three management techniques over a period of three years (2003-05) monitoring their effects on seed cotton yield and soil fertility. The techniques included chemical fertilizers, municipal solid waste manure (MSWM) integrated with chemical fertilizers in 1:4 ratios with, and without pesticides. The results revealed that cotton yields. Were enhanced by 19% due to site-specific fertilizer dose over conventional dose. Ignoring weeds control by means of herbicided application resulted in 5% decrease of seed cotton yield in IPNM technique positive effect of MSWM integration was noted on soil test phosphorus and SOM. Site-specific fertilizer application and integrated plant nutrient management by MSWM proved their suitability as the techniques not only improve soil quality in terms of sustained levels of organic matter and phosphorus but also provide a safe way of waste disposal. (author)

A model for automation of radioactive dose control

International Nuclear Information System (INIS)

Ribeiro, Carlos Henrique Calazans; Zambon, Jose Waldir; Bitelli, Ricardo; Honaiser, Eduardo Henrique Rangel

2009-01-01

The paper presents a proposal for automation of the personnel dose control system to be used in nuclear medicine environments. The model has considered the Standards and rules of the National Commission of Nuclear Energy (CNEN) and of the Health Ministry. The advantages of the model is a robust management of the integrated dose and technicians qualification status. The software platform selected to be used was the Lotus Notes and an analysis of the advantages, disadvantages of the use of this platform is also presented. (author)

A model for automation of radioactive dose control

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Carlos Henrique Calazans; Zambon, Jose Waldir; Bitelli, Ricardo; Honaiser, Eduardo Henrique Rangel [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)], e-mail: calazans@ctmsp.mar.mil.br, e-mail: zambon@ctmsp.mar.mil.br, e-mail: bitelli@ctmsp.mar.mil.br, e-mail: honaiser@ctmsp.mar.mil.br

2009-07-01

The paper presents a proposal for automation of the personnel dose control system to be used in nuclear medicine environments. The model has considered the Standards and rules of the National Commission of Nuclear Energy (CNEN) and of the Health Ministry. The advantages of the model is a robust management of the integrated dose and technicians qualification status. The software platform selected to be used was the Lotus Notes and an analysis of the advantages, disadvantages of the use of this platform is also presented. (author)

Dose specification for radiation therapy: dose to water or dose to medium?

International Nuclear Information System (INIS)

Ma, C-M; Li Jinsheng

2011-01-01

The Monte Carlo method enables accurate dose calculation for radiation therapy treatment planning and has been implemented in some commercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water with variable electron density, the Monte Carlo method calculates the energy deposition in different media and expresses dose to a medium. This paper discusses the differences in dose calculated using water with different electron densities and that calculated for different biological media and the clinical issues on dose specification including dose prescription and plan evaluation using dose to water and dose to medium. We will demonstrate that conventional photon dose calculation algorithms compute doses similar to those simulated by Monte Carlo using water with different electron densities, which are close (<4% differences) to doses to media but significantly different (up to 11%) from doses to water converted from doses to media following American Association of Physicists in Medicine (AAPM) Task Group 105 recommendations. Our results suggest that for consistency with previous radiation therapy experience Monte Carlo photon algorithms report dose to medium for radiotherapy dose prescription, treatment plan evaluation and treatment outcome analysis.

Dose record keeping: a multi purpose tool in individual monitoring

International Nuclear Information System (INIS)

Bermann, F.; Julius, H.W.

1993-01-01

Proper recording of radiation doses is an essential part of the process of individual monitoring and shares in the same objective. A dose record keeping system is more than just a computer based data storage system and should rather be a Dose Registration and Information System (DRIS). Objectives of dose record keeping are given. As a result of the integration of member states of the European Communities, co-operation and exchange of personnel between countries will be increasing. This will probably require national dose registration systems and adequate data communication between them. These developments emphasize the necessity for international harmonization of dose record keeping systems and categorization of the data they contain. General characteristics and specific aspects of dose record keeping systems will be dealt with. Attention will also be given to some special applications of the recorded information, such as: the use of data for epidemiological studies and for QA purposes. (authors). 5 tabs., 4 refs

Volume dose of organs at risk in the irradiated volume

International Nuclear Information System (INIS)

Hishikawa, Yoshio; Tanaka, Shinichi; Miura, Takashi

1984-01-01

Absorbed dose of organs at risk in the 50% irradiated volume needs to be carefully monitored because there is high risk of radiation injury. This paper reports on the histogram of threedimensional volume dose of organs at risk, which is obtained by computer calculation of CT scans. In order to obtain this histogram, CT is first performed in the irradiation field. The dose in each pixel is then examined by the computer as to each slice. After the pixels of all slices in the organ at risk of the irradiated field are classified according to the doses, the number of pixels in the same dose class is counted. The result is expressed in a histogram. The histogram can show the differences of influence to organs at risk given by various radiation treatment techniques. Total volume dose of organs at risk after radiotherapy can also be obtained by integration of each dose of different treatment techniques. (author)

The remobilisation of radionuclides from marine sediments: implications for collective dose assessments

International Nuclear Information System (INIS)

Nicholson, S.; MacKenzie, J.

1988-09-01

A model of the transfer (in either direction) of radioactivity between seawater and the seabed is described. It was developed, in the first instance, for inclusion in marine collective dose assessment codes. A review of radionuclide-sediment interactions with particular emphasis on the remobilisation process is followed by a description of the seabed model, an investigation of the effect of the model on estimates of collective dose, and a discussion of sedimentation in the Irish Sea in the context of radioactive discharges. The inclusion of the seabed model may lead to marked decreases in the collective dose at short integration times for nuclides with a high affinity for sediments. For discharges of such radionuclides into the Irish Sea, remobilisation may lead to a significant increase in collective dose compared with estimates obtained ignoring this phenomenon; and thirdly, remobilisation appears to have little effect on collective doses integrated to infinite time for discharges from three other locations in the UK. It is also shown that inclusion of the seabed model leads to predictions of a high uptake of plutonium by the seabed for Irish Sea discharges without the need for anomalously high sedimentation rates. (author)

Effect of automated tube voltage selection, integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of 3rd generation dual-source aortic CT angiography: An intra-individual comparison.

Science.gov (United States)

Mangold, Stefanie; De Cecco, Carlo N; Wichmann, Julian L; Canstein, Christian; Varga-Szemes, Akos; Caruso, Damiano; Fuller, Stephen R; Bamberg, Fabian; Nikolaou, Konstantin; Schoepf, U Joseph

2016-05-01

To compare, on an intra-individual basis, the effect of automated tube voltage selection (ATVS), integrated circuit detector and advanced iterative reconstruction on radiation dose and image quality of aortic CTA studies using 2nd and 3rd generation dual-source CT (DSCT). We retrospectively evaluated 32 patients who had undergone CTA of the entire aorta with both 2nd generation DSCT at 120kV using filtered back projection (FBP) (protocol 1) and 3rd generation DSCT using ATVS, an integrated circuit detector and advanced iterative reconstruction (protocol 2). Contrast-to-noise ratio (CNR) was calculated. Image quality was subjectively evaluated using a five-point scale. Radiation dose parameters were recorded. All studies were considered of diagnostic image quality. CNR was significantly higher with protocol 2 (15.0±5.2 vs 11.0±4.2; p<.0001). Subjective image quality analysis revealed no significant differences for evaluation of attenuation (p=0.08501) but image noise was rated significantly lower with protocol 2 (p=0.0005). Mean tube voltage and effective dose were 94.7±14.1kV and 6.7±3.9mSv with protocol 2; 120±0kV and 11.5±5.2mSv with protocol 1 (p<0.0001, respectively). Aortic CTA performed with 3rd generation DSCT, ATVS, integrated circuit detector, and advanced iterative reconstruction allow a substantial reduction of radiation exposure while improving image quality in comparison to 120kV imaging with FBP. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Evaluation of doses delivered during CT examination by different scanners for purposes of intercomparison and dose optimization

International Nuclear Information System (INIS)

Bashiru, Adam

2017-07-01

This research study was aimed at performing dosimetry intercomparison on different CT scanners in the diagnostic radiology departments of Korle-Bu Teaching Hospital (KBTH), Sweden Ghana Medical Center (SGMC) and Global Medical and Imaging Center (GMIC). Using the standard body phantom and integrated ion chamber technique volume computed tomography dose index (CTDIvol) and Dose-Length Product (DLPs) within the phantom were evaluated. The ion chamber technique was applied to two 16 slice Siemens and one Toshiba Aquilion one CT scanners. CTDIvol and DLP values for the standard body polymethyl methacrylate (PMMA) phantom were estimated and comparison made with corresponding console displayed values for accuracy and also to deduce a suitable method for optimization of patients and occupationally exposed worker doses. Effective doses were also calculated. An intra and inter institutional comparison of measured doses and console displayed doses were performed. Chest protocol at Automatic Exposure Control (AEC) was applied during the scanning of the phantom. Estimated CTDIvol values (mGy) were 17mGy, 24mGy and 13.1mGy for SGMC, GMIC and KBTH respectively. These values deviated from the console displayed values by 24.1%, 22.9% and 31.3% respectively. Similarly, estimated DLP values (mGy.cm) were 675mGy.cm,944mGy.cm and 419mGy.cm for SGMC, GMIC and KBTH respectively deviating from the console displayed values by 24.1%, 24.2% and 29% respectively. In terms of effective doses (E), the calculated E (mSv) values were 9.45mSv, 13.2mSv and 5.87mSv estimated from the DLPs from SGMC, GMIC and KBTH respectively using K, the anatomy-specific dose coefficient expressing effective dose normalized to DLP in a standard CT dosimetry phantom of 0.014 mSv mGy-1 cm-1. The estimated doses were compared to other selected international Dose Reference Levels (DRLs) and were within range. (au)

Review of low dose-rate epidemiological studies and biological mechanisms of dose-rate effects on radiation induced carcinogenesis

International Nuclear Information System (INIS)

Iwasaki, Toshiyasu; Otsuka, Kensuke; Yoshida, Kazuo

2015-01-01

Radiation protection system adopts the linear non-threshold model with using dose and dose-rate effectiveness factor (DDREF). The dose-rate range where DDREF is applied is below 100 mGy per hour, and it is regarded that there are no dose-rate effects at very low dose rate, less than of the order of 10 mGy per year, even from the biological risk evaluation model based on cellular and molecular level mechanisms for maintenance of genetic integrity. Among low dose-rate epidemiological studies, studies of residents in high natural background areas showed no increase of cancer risks at less than about 10 mGy per year. On the other hand, some studies include a study of the Techa River cohort suggested the increase of cancer risks to the similar degree of Atomic bomb survivor data. The difference of those results was supposed due to the difference of dose rate. In 2014, International Commission on Radiological Protection opened a draft report on stem cell biology for public consultations. The report proposed a hypothesis based on the new idea of stem cell competition as a tissue level quality control mechanism, and suggested that it could explain the dose-rate effects around a few milligray per year. To verify this hypothesis, it would be needed to clarify the existence and the lowest dose of radiation-induced stem cell competition, and to elucidate the rate of stem cell turnover and radiation effects on it. As for the turnover, replenishment of damaged stem cells would be the important biological process. It would be meaningful to collect the information to show the difference of dose rates where the competition and the replenishment would be the predominant processes. (author)

Isocentric integration of intensity-modulated radiotherapy with electron fields improves field junction dose uniformity in postmastectomy radiotherapy.

Science.gov (United States)

Wright, Pauliina; Suilamo, Sami; Lindholm, Paula; Kulmala, Jarmo

2014-08-01

In postmastectomy radiotherapy (PMRT), the dose coverage of the planning target volume (PTV) with additional margins, including the chest wall, supraclavicular, interpectoral, internal mammary and axillar level I-III lymph nodes, is often compromised. Electron fields may improve the medial dose coverage while maintaining organ at risk (OAR) doses at an acceptable level, but at the cost of hot and cold spots at the electron and photon field junction. To improve PMRT dose coverage and uniformity, an isocentric technique combining tangential intensity-modulated (IM)RT fields with one medial electron field was implemented. For 10 postmastectomy patients isocentric IMRT with electron plans were created and compared with a standard electron/photon mix and a standard tangent technique. PTV dose uniformity was evaluated based on the tolerance range (TR), i.e. the ratio of the standard deviation to the mean dose, a dice similarity coefficient (DSC) and the 90% isodose coverage and the hot spot volumes. OAR and contralateral breast doses were also recorded. IMRT with electrons significantly improved the PTV dose homogeneity and conformity based on the TR and DSC values when compared with the standard electron/photon and tangent technique (p < 0.02). The 90% isodose coverage improved to 86% compared with 82% and 80% for the standard techniques (p < 0.02). Compared with the standard electron/photon mix, IMRT smoothed the dose gradient in the electron and photon field junction and the volumes receiving a dose of 110% or more were reduced by a third. For all three strategies, the OAR and contralateral breast doses were within clinically tolerable limits. Based on these results two-field IMRT combined with an electron field is a suitable strategy for PMRT.

Actual trends in patients dose reduction in radiodiagnostic

International Nuclear Information System (INIS)

Nikodemova, D.; Gomola, I.; Horvathova, M.

2001-01-01

In our contribution we tried to survey the entrance surface doses, as well as dose area product measurements by studying 3 types of radiodiagnostic examinations (mammography, chest examination of children and fluoroscopy). The analysis of the obtained data and their comparison with reference values of European Union has demonstrated the significant role of radiation protection dosimetry as an integral part of quality assurance strategy in radiology. Optimisation in radiodiagnostic requires fulfilling the following criteria: - patient doses to be in accordance with accepted diagnostic practice; - patient doses to be as low as reasonably practicable in order to achieve the required diagnostic results; - professionals clinically and physically directing medical exposures to be familiar with typical doses, methods of measurements and means of dose reduction. One of the basic requirements for continuous quality improvement is the repeating cycle of patient dose measurements for determining the level of risk associated with particular radiological examination at given radiodiagnostic department. Beside the undeniable positive influence of Quality Assurance (QA) procedures possible negative effects should be avoided. The danger exist that the development of new techniques is slowed down by standardising all procedures and wide agreement in implementing of required modifications. Reaching of a consensus of a certain procedure became therefore a labour intensive and time-consuming process. (authors)

An automated dose tracking system for adaptive radiation therapy.

Science.gov (United States)

Liu, Chang; Kim, Jinkoo; Kumarasiri, Akila; Mayyas, Essa; Brown, Stephen L; Wen, Ning; Siddiqui, Farzan; Chetty, Indrin J

2018-02-01

The implementation of adaptive radiation therapy (ART) into routine clinical practice is technically challenging and requires significant resources to perform and validate each process step. The objective of this report is to identify the key components of ART, to illustrate how a specific automated procedure improves efficiency, and to facilitate the routine clinical application of ART. Data was used from patient images, exported from a clinical database and converted to an intermediate format for point-wise dose tracking and accumulation. The process was automated using in-house developed software containing three modularized components: an ART engine, user interactive tools, and integration tools. The ART engine conducts computing tasks using the following modules: data importing, image pre-processing, dose mapping, dose accumulation, and reporting. In addition, custom graphical user interfaces (GUIs) were developed to allow user interaction with select processes such as deformable image registration (DIR). A commercial scripting application programming interface was used to incorporate automated dose calculation for application in routine treatment planning. Each module was considered an independent program, written in C++or C#, running in a distributed Windows environment, scheduled and monitored by integration tools. The automated tracking system was retrospectively evaluated for 20 patients with prostate cancer and 96 patients with head and neck cancer, under institutional review board (IRB) approval. In addition, the system was evaluated prospectively using 4 patients with head and neck cancer. Altogether 780 prostate dose fractions and 2586 head and neck cancer dose fractions went processed, including DIR and dose mapping. On average, daily cumulative dose was computed in 3 h and the manual work was limited to 13 min per case with approximately 10% of cases requiring an additional 10 min for image registration refinement. An efficient and convenient

Aging of magnesium stearate under high doses gamma irradiation and oxidative conditions

Energy Technology Data Exchange (ETDEWEB)

Lebeau, D.; Beuvier, L.; Cornaton, M. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Tabarant, M. [CEA, DEN, DPC, SEARS, LISL, F-91191 Gif-sur-Yvette (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France)

2015-05-15

Highlights: • Magnesium stearate was radio-oxidized at very high doses using gamma-rays. • H{sub 2} emission was estimated as a function of the integrated dose. • Modifications in the organic solid were followed as a function of the integrated dose. • A non-exhaustive degradation mechanism of magnesium stearate was proposed. - Abstract: In nuclear waste packages conditioning processes, magnesium stearate is widely used because of its high lubricating properties. For safety purposes, the radiolytic degradation of these organic materials has to be better understood to be able to predict their aging in repository conditions. This study reports the radiolytic degradation of magnesium stearate, using gamma-rays at room temperature and under air. Modifications were followed using different analytical tools (XPS, ATR-FTIR, ICP-AES, ATG and mass spectrometry). It has been observed that molecules mainly formed up to 1000 kGy of gamma irradiation dose under radio-oxidation are alkanes, hydroperoxides, double bonds in the aliphatic chain, carboxylates with aliphatic chain shorter than the one of stearate and ketones. At a dose of 4000 kGy, dicarboxylic acids are observed: the formation of these molecules needs a dose of at least 1000 kGy to be created under radio-oxidation. These observations allow us to propose a non-exhaustive degradation mechanism of magnesium stearate under gamma-irradiation at room temperature and under air.

First Results from the Online Radiation Dose Monitoring System in ATLAS experiment

CERN Document Server

Mandić, I; The ATLAS collaboration; Deliyergiyev, M; Gorišek, A; Kramberger, G; Mikuž, M; Franz, S; Hartert, J; Dawson, I; Miyagawa, P; Nicolas, L

2011-01-01

High radiation doses which will accumulate in components of ATLAS experiment during data taking will causes damage to detectors and readout electronics. It is therefore important to continuously monitor the doses to estimate the level of degradation caused by radiation. Online radiation monitoring system measures ionizing dose in SiO2 , displacement damage in silicon in terms of 1-MeV(Si) equivalent neutron fluence and fluence of thermal neutrons at several locations in ATLAS detector. In this paper design of the system, results of measurements and comparison of measured integrated doses and fluences with predictions from FLUKA simulation will be shown.

Experimental measurements of spatial dose distributions in radiosurgery treatments

International Nuclear Information System (INIS)

Avila-Rodriguez, M. A.; Rodriguez-Villafuerte, M.; Diaz-Perches, R.; Perez-Pastenes, M. A.

2001-01-01

The measurement of stereotactic radiosurgery dose distributions requires an integrating, high-resolution dosimeter capable of providing a spatial map of absorbed dose. This paper describes the use of a commercial radiochromic dye film (GafChromic MD-55-2) to measure radiosurgery dose distributions with 6 MV X-rays in a head phantom. The response of the MD-55-2 was evaluated by digitizing and analyzing the films with conventional computer systems. Radiosurgery dose distributions were measured using the radiochromic film in a spherical acrylic phantom of 16 cm diameter undergoing a typical SRS treatment as a patient, and were compared with dose distributions provided by the treatment planning system. The comparison lead to mean radial differences of ±0.6 mm, ±0.9 mm, ±1.3 mm, ±1.9 mm, and ±2.8 mm, for the 80, 60, 50, 40, and 30% isodose curves, respectively. It is concluded that the radiochromic film is a convenient and useful tool for radiosurgery treatment planning validation

Development of microcontroller based instrumentation for low dose implantation

International Nuclear Information System (INIS)

Suresh, K.; Saravanan, K.; Panigrahi, B.K.; Nair, K.G.M.

2011-01-01

In experiments like ion implantation based ion track formations, the sample is implanted to low doses of the order of 10 10 ions/cm 2 , limiting the ion beam currents to be less than 1-5 x 10 -12 A. However the standard current integrators available are not sensitive to very low currents, causing an unacceptable high level of error in dose measurement. Hence a low dose implantation measurement system has been developed. It consists of a very sensitive low current preamplifier with full scale input 1nA/100pA, a standard current integrator, a microcontroller based interface circuit, which are connected to a personal computer(PC) through USB. Two types of the software are developed for the system: the microcontroller firmware using C and windows based virtual instrument programs using LabVIEW 7.0. Necessary precautions associated with pA level measurement like rigidly fastened good quality cables, low ripple DC power supply, shielding, close mounting of the preamplifier to the sample are adopted. After necessary calibrations with an ECIL make low current source, the system has been put into regular use. Design and development details, salient features are discussed in this paper. (author)

JADA: a graphical user interface for comprehensive internal dose assessment in nuclear medicine.

Science.gov (United States)

Grimes, Joshua; Uribe, Carlos; Celler, Anna

2013-07-01

The main objective of this work was to design a comprehensive dosimetry package that would keep all aspects of internal dose calculation within the framework of a single software environment and that would be applicable for a variety of dose calculation approaches. Our MATLAB-based graphical user interface (GUI) can be used for processing data obtained using pure planar, pure SPECT, or hybrid planar/SPECT imaging. Time-activity data for source regions are obtained using a set of tools that allow the user to reconstruct SPECT images, load images, coregister a series of planar images, and to perform two-dimensional and three-dimensional image segmentation. Curve fits are applied to the acquired time-activity data to construct time-activity curves, which are then integrated to obtain time-integrated activity coefficients. Subsequently, dose estimates are made using one of three methods. The organ level dose calculation subGUI calculates mean organ doses that are equivalent to dose assessment performed by OLINDA/EXM. Voxelized dose calculation options, which include the voxel S value approach and Monte Carlo simulation using the EGSnrc user code DOSXYZnrc, are available within the process 3D image data subGUI. The developed internal dosimetry software package provides an assortment of tools for every step in the dose calculation process, eliminating the need for manual data transfer between programs. This saves times and minimizes user errors, while offering a versatility that can be used to efficiently perform patient-specific internal dose calculations in a variety of clinical situations.

Managing patient dose in digital radiology

International Nuclear Information System (INIS)

2014-01-01

Digital techniques have the potential to improve the practice of radiology but they also risk the overuse of radiation. The main advantages of digital imaging, i.e. wide dynamic range, post processing, multiple viewing options, and electronic transfer and archiving possibilities, are clear but overexposures can occur without an adverse impact on image quality. In conventional radiography, excessive exposure produces a black film. In digital systems, good images are obtained for a large range of doses. It is very easy to obtain (and delete) images with digital fluoroscopy systems, and there may be a tendency to obtain more images than necessary. In digital radiology, higher patient dose usually means improved image quality, so a tendency to use higher patient doses than necessary could occur. Different medical imaging tasks require different levels of image quality, and doses that have no additional benefit for the clinical purpose should be avoided. Image quality can be compromised by inappropriate levels of data compression and/or post processing techniques. All these new challenges should be part of the optimisation process and should be included in clinical and technical protocols. Local diagnostic reference levels should be re-evaluated for digital imaging, and patient dose parameters should be displayed at the operator console. Frequent patient dose audits should occur when digital techniques are introduced. Training in the management of image quality and patient dose in digital radiology is necessary. Digital radiology will involve new regulations and invoke new challenges for practitioners. As digital images are easier to obtain and transmit, the justification criteria should be reinforced. Commissioning of digital systems should involve clinical specialists, medical physicists, and radiographers to ensure that imaging capability and radiation dose management are integrated. Quality control requires new procedures and protocols (visualisation, transmission

Dose tracking and dose auditing in a comprehensive computed tomography dose-reduction program.

Science.gov (United States)

Duong, Phuong-Anh; Little, Brent P

2014-08-01

Implementation of a comprehensive computed tomography (CT) radiation dose-reduction program is a complex undertaking, requiring an assessment of baseline doses, an understanding of dose-saving techniques, and an ongoing appraisal of results. We describe the role of dose tracking in planning and executing a dose-reduction program and discuss the use of the American College of Radiology CT Dose Index Registry at our institution. We review the basics of dose-related CT scan parameters, the components of the dose report, and the dose-reduction techniques, showing how an understanding of each technique is important in effective auditing of "outlier" doses identified by dose tracking. Copyright © 2014 Elsevier Inc. All rights reserved.

Radiation dose in mammography: an energy-balance approach

International Nuclear Information System (INIS)

Shrivastava, P.N.

1981-01-01

An energy-balance approach for calculation of mean, integral, and midpoint doses in mammography is introduced. Estimation of mean absorbed dose for individual applications is described. Differences in breast composition and thickness are accounted for by simple measurements of entrance and exit exposures. Calculations made for a range of xeromammographic techniques used at various breast cancer detection centers show that although increasing the beam h.v.l. dramatically decreases breast surface exposure, it is insignificant in lowering mean breast dose or radiation risk. Thus selection of a moderate h.v.l. to optimize image quality (soft-tissue contrast) in xeromammography may be more beneficial than unduly increasing h.v.l. merely to reduce surface exposure. The mean breast dose per mammogram with low-h.v.l. screen-film techniques was 3 to 9 times lower than for xeromammography, suggesting that general acceptance of screen-film techniques can significantly reduce the risk associated with mammography

Computer Based Dose Control System on Linear Accelerator

International Nuclear Information System (INIS)

Taxwim; Djoko-SP; Widi-Setiawan; Agus-Budi Wiyatna

2000-01-01

The accelerator technology has been used for radio therapy. DokterKaryadi Hospital in Semarang use electron or X-ray linear accelerator (Linac)for cancer therapy. One of the control parameter of linear accelerator isdose rate. It is particle current or amount of photon rate to the target. Thecontrol of dose rate in linac have been done by adjusting repetition rate ofanode pulse train of electron source. Presently the control is stillproportional control. To enhance the quality of the control result (minimalstationer error, velocity and stability), the dose control system has beendesigned by using the PID (Proportional Integral Differential) controlalgorithm and the derivation of transfer function of control object.Implementation of PID algorithm control system is done by giving an input ofdose error (the different between output dose and dose rate set point). Theoutput of control system is used for correction of repetition rate set pointfrom pulse train of electron source anode. (author)

Comparison of proton and photon dose distributions

International Nuclear Information System (INIS)

Goitein, Michael

1995-01-01

Recently, there has been considerable work, as yet largely theoretical, in developing ways to improve the dose distributions which can be achieved with x-rays. Foremost among these developments are the use of non-coplanar beam directions, the use of intensity-modulated beams, and the implementation of computer-controlled delivery of complex plans using new beam modifiers such as multi-leaf collimators and beam scanners. One way of improving the dose distributions which have been achieved with conventional radiations is to use protons, with their quite different physical characteristics but very similar radiobiological properties as compared with supervoltage x-rays. Some substantial experience has been gained in the use of protons which has confirmed clinically that better results have been obtained as a result of their better dose distributions. Indeed, it is fair to say that the advantages which protons have demonstrated are, in large part, responsible for the renewed interest in improving the dose distributions from all radiation modalities. So much better are the dose distributions which the new techniques, mentioned above, offer that there is the impression that, with their use, photons can deliver dose distributions as good as can be obtained with protons. In this paper, the extent of the possible improvement will be discussed. It will be suggested that the integral dose is relatively little affected by the treatment technique - so that the lower normal tissue doses which the new approaches offer is almost always at the price of delivering dose to a larger volume. Protons can be matched pencil beam for pencil beam with photons - and then almost always deliver substantially less dose outside the target volume. Ultimately, the clinical importance of the differences will have to decided by clinical trial

The determination of effective doses from the intake of tritiated water

International Nuclear Information System (INIS)

1987-08-01

To comply with the regulatory requirements relating to the dose from exposures to tritiated water (HTO), Atomic Energy Control Board (AECB) licensees currently measure tritium concentration in urine to determine whole body dose. This approach has been based on the consideration that the time-integrated tritium concentration (which is proportional to accumulated dose) in any organ from urine concentrations are always conservative. The International Commission on Radiological Protection (ICRP) recommends that the average soft tissue dose be used to determine effective dose equivalents for HTO exposures. The ICRP also recommends that only the retention in body water be considered when committed doses from HTO exposures are calculated; this recommendation is based on the consideration that the errors introduced by neglecting the long-lived tritium component (those tritium atoms retained in organic molecules of the body cells) are small (only of the order of 10% of the committed dose equivalent to the whole body). The AECB position is presented in the following regulatory policy statement

Validation of a new control system for Elekta accelerators facilitating continuously variable dose rate

DEFF Research Database (Denmark)

Bertelsen, Anders; Lorenzen, Ebbe L; Brink, Carsten

2011-01-01

) as well as BVDR. Using CVDR opposed to BVDR for VMAT has the potential of reducing the treatment time but may lead to lower dosimetric accuracy due to faster moving accelerator parts. Using D7 and a test version of Integrity, differences in ability to control the accelerator, treatment efficiency......Elekta accelerators controlled by the current clinically used accelerator control system, Desktop 7.01 (D7), uses binned variable dose rate (BVDR) for volumetric modulated arc therapy (VMAT). The next version of the treatment control system (Integrity) supports continuously variable dose rate (CVDR...

Shielding optimisation of the ITER ICH&CD antenna for shutdown dose rate

International Nuclear Information System (INIS)

Turner, Andrew; Leichtle, Dieter; Lamalle, Philippe; Levesy, Bruno; Meunier, Lionel; Polunovskiy, Eduard; Sartori, Roberta; Shannon, Mark

2015-01-01

Highlights: • Neutronics analysis on the ITER ICH&CD system conducted to reduce shutdown dose rate. • Several designs for shielding the port plug gaps were modelled. • Shielding significantly reduced interspace dose rate but still exceed project requirements. • Design optimisation of the ICH port is continuing. • Significant contributions from other ports require an integrated modelling approach. - Abstract: The Ion Cyclotron Heating and Current Drive (ICH&CD) system will reside in ITER equatorial port plugs 13 and 15. Shutdown dose rates (SDDR) within the port interspace are required to be less than 100 μSv/h at 10 6 s cooling. A significant contribution to the SDDR results from neutrons streaming down gaps around the port frame, and the mitigation of this streaming is the main subject of these analyses. An updated MCNP model of the antenna was created and integrated into an ITER reference model. Shielding plates were defined in the port gaps, and scoping studies conducted to assess their effectiveness in several configurations, based on which a front dog-leg arrangement was selected for high resolution 3-D activation analysis using MCR2S. It was concluded that the selected configuration reduced the SDDR from ∼500 μSv/h to 220 μSv/h but were still in excess of dose rate requirements. Approximately 30% of this was due to cross-talk from neighbouring ports. In addition, increased dose rates were observed in the port interspace along the lines of sight of the removable vacuum transmission lines. Design optimisation is continuing, however an integrated approach is needed with regard to ITER port plug design and the shielding of surrounding systems.

Shielding optimisation of the ITER ICH&CD antenna for shutdown dose rate

Energy Technology Data Exchange (ETDEWEB)

Turner, Andrew, E-mail: andrew.turner@ccfe.ac.uk [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Leichtle, Dieter [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Lamalle, Philippe; Levesy, Bruno [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St., Paul-lez-Durance (France); Meunier, Lionel [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Polunovskiy, Eduard [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St., Paul-lez-Durance (France); Sartori, Roberta [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Shannon, Mark [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2015-10-15

Highlights: • Neutronics analysis on the ITER ICH&CD system conducted to reduce shutdown dose rate. • Several designs for shielding the port plug gaps were modelled. • Shielding significantly reduced interspace dose rate but still exceed project requirements. • Design optimisation of the ICH port is continuing. • Significant contributions from other ports require an integrated modelling approach. - Abstract: The Ion Cyclotron Heating and Current Drive (ICH&CD) system will reside in ITER equatorial port plugs 13 and 15. Shutdown dose rates (SDDR) within the port interspace are required to be less than 100 μSv/h at 10{sup 6} s cooling. A significant contribution to the SDDR results from neutrons streaming down gaps around the port frame, and the mitigation of this streaming is the main subject of these analyses. An updated MCNP model of the antenna was created and integrated into an ITER reference model. Shielding plates were defined in the port gaps, and scoping studies conducted to assess their effectiveness in several configurations, based on which a front dog-leg arrangement was selected for high resolution 3-D activation analysis using MCR2S. It was concluded that the selected configuration reduced the SDDR from ∼500 μSv/h to 220 μSv/h but were still in excess of dose rate requirements. Approximately 30% of this was due to cross-talk from neighbouring ports. In addition, increased dose rates were observed in the port interspace along the lines of sight of the removable vacuum transmission lines. Design optimisation is continuing, however an integrated approach is needed with regard to ITER port plug design and the shielding of surrounding systems.

Radiation dose-response relationship of micronucleus occurrence in pollen mother cells of tradescantia

International Nuclear Information System (INIS)

Kim, Jin Kyu; Kim, Yeon Ku; Song, Hi Sup

1999-01-01

This study was carried out to investigate the radiation dose-response of micronucleus frequencies in Tradescantia pollen mother cells. The number of micronuclei increased in the tetrads as a result of chromosome deletion after irradiation. The maximal frequency of micronucleus showed a good dose-response relationship in the range of dose 0∼50 cGy. On the basis of the relationship, a dose of 1 cGy resulted in two additional micronuclei in 100 tetrads. The radiation dose-response relationship of micronucleus occurrence is prerequisite to biological monitoring of radiation and can be modified for biological risk assessment of toxicants, and to safety test of water or soil integrity

Concepts for dose determination in flat-detector CT

Science.gov (United States)

Kyriakou, Yiannis; Deak, Paul; Langner, Oliver; Kalender, Willi A.

2008-07-01

Flat-detector computed tomography (FD-CT) scanners provide large irradiation fields of typically 200 mm in the cranio-caudal direction. In consequence, dose assessment according to the current definition of the computed tomography dose index CTDIL=100 mm, where L is the integration length, would demand larger ionization chambers and phantoms which do not appear practical. We investigated the usefulness of the CTDI concept and practical dosimetry approaches for FD-CT by measurements and Monte Carlo (MC) simulations. An MC simulation tool (ImpactMC, VAMP GmbH, Erlangen, Germany) was used to assess the dose characteristics and was calibrated with measurements of air kerma. For validation purposes measurements were performed on an Axiom Artis C-arm system (Siemens Medical Solutions, Forchheim, Germany) equipped with a flat detector of 40 cm × 30 cm. The dose was assessed for 70 kV and 125 kV in cylindrical PMMA phantoms of 160 mm and 320 mm diameter with a varying phantom length from 150 to 900 mm. MC simulation results were compared to the values obtained with a calibrated ionization chambers of 100 mm and 250 mm length and to thermoluminesence (TLD) dose profiles. The MCs simulations were used to calculate the efficiency of the CTDIL determination with respect to the desired CTDI∞. Both the MC simulation results and the dose distributions obtained by MC simulation were in very good agreement with the CTDI measurements and with the reference TLD profiles, respectively, to within 5%. Standard CTDI phantoms which have a z-extent of 150 mm underestimate the dose at the center by up to 55%, whereas a z-extent of >=600 mm appears to be sufficient for FD-CT; the baseline value of the respective profile was within 1% to the reference baseline. As expected, the measurements with ionization chambers of 100 mm and 250 mm offer a limited accuracy, whereas an increased integration length of >=600 mm appeared to be necessary to approximate CTDI∞ in within 1%. MC simulations

Heart dose reduction in breast cancer treatment with simultaneous integrated boost. Comparison of treatment planning and dosimetry for a novel hybrid technique and 3D-CRT

International Nuclear Information System (INIS)

Joest, Vincent; Kretschmer, Matthias; Sabatino, Marcello; Wuerschmidt, Florian; Dahle, Joerg; Lorenzen, Joern; Ueberle, Friedrich

2015-01-01

The present study compares in silico treatment plans of clinically established three-dimensional conformal radiotherapy (3D-CRT) with a hybrid technique consisting of intensity-modulated radiotherapy (IMRT) and volumetric modulated arc radiotherapy (VMAT) during normally fractionated radiation of mammary carcinomas with simultaneous integrated boost on the basis of dose-volume histogram (DVH) parameters. Radiation treatment planning was performed with a hybrid and a 3D-CRT treatment plan for 20 patients. Hybrid plans were implemented with two tangential IMRT fields and a VMAT field in the angular range of the tangents. Verification of the plan was performed with a manufacturer-independent measurement system consisting of a detector array and rotation unit. The mean values of the heart dose for the entire patient collective were 3.6 ± 2.5 Gy for 3D-CRT and 2.9 ± 2.1 Gy for the hybrid technique (p < 0.01). For the left side (n = 10), the mean values for the left anterior descending artery were 21.8 ± 7.4 Gy for 3D-CRT and 17.6 ± 7.4 Gy for the hybrid technique (p < 0.01). The mean values of the ipsilateral lung were 11.9 ± 1.6 Gy for 3D-CRT and 10.5 ± 1.3 Gy for the hybrid technique (p < 0.01). Calculated dose distributions in the hybrid arm were in good accordance with measured dose (on average 95.6 ± 0.5 % for γ < 1 and 3 %/3 mm). The difference of the mean treatment time per fraction was 7 s in favor of 3D-CRT. Compared with the established 3D-CRT technique, the hybrid technique allows for a decrease in dose, particularly of the mean heart and lung dose with comparable target volume acquisition and without disadvantageous low-dose load of contralateral structures. Uncomplicated implementation of the hybrid technique was demonstrated in this context. The hybrid technique combines the advantages of tangential IMRT with the superior sparing of organs at risk by VMAT. (orig.) [de

Optimization of equivalent uniform dose using the L-curve criterion

International Nuclear Information System (INIS)

Chvetsov, Alexei V; Dempsey, James F; Palta, Jatinder R

2007-01-01

Optimization of equivalent uniform dose (EUD) in inverse planning for intensity-modulated radiation therapy (IMRT) prevents variation in radiobiological effect between different radiotherapy treatment plans, which is due to variation in the pattern of dose nonuniformity. For instance, the survival fraction of clonogens would be consistent with the prescription when the optimized EUD is equal to the prescribed EUD. One of the problems in the practical implementation of this approach is that the spatial dose distribution in EUD-based inverse planning would be underdetermined because an unlimited number of nonuniform dose distributions can be computed for a prescribed value of EUD. Together with ill-posedness of the underlying integral equation, this may significantly increase the dose nonuniformity. To optimize EUD and keep dose nonuniformity within reasonable limits, we implemented into an EUD-based objective function an additional criterion which ensures the smoothness of beam intensity functions. This approach is similar to the variational regularization technique which was previously studied for the dose-based least-squares optimization. We show that the variational regularization together with the L-curve criterion for the regularization parameter can significantly reduce dose nonuniformity in EUD-based inverse planning

Optimization of equivalent uniform dose using the L-curve criterion

Energy Technology Data Exchange (ETDEWEB)

Chvetsov, Alexei V; Dempsey, James F; Palta, Jatinder R [Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385 (United States)

2007-09-21

Optimization of equivalent uniform dose (EUD) in inverse planning for intensity-modulated radiation therapy (IMRT) prevents variation in radiobiological effect between different radiotherapy treatment plans, which is due to variation in the pattern of dose nonuniformity. For instance, the survival fraction of clonogens would be consistent with the prescription when the optimized EUD is equal to the prescribed EUD. One of the problems in the practical implementation of this approach is that the spatial dose distribution in EUD-based inverse planning would be underdetermined because an unlimited number of nonuniform dose distributions can be computed for a prescribed value of EUD. Together with ill-posedness of the underlying integral equation, this may significantly increase the dose nonuniformity. To optimize EUD and keep dose nonuniformity within reasonable limits, we implemented into an EUD-based objective function an additional criterion which ensures the smoothness of beam intensity functions. This approach is similar to the variational regularization technique which was previously studied for the dose-based least-squares optimization. We show that the variational regularization together with the L-curve criterion for the regularization parameter can significantly reduce dose nonuniformity in EUD-based inverse planning.

Optimization of equivalent uniform dose using the L-curve criterion.

Science.gov (United States)

Chvetsov, Alexei V; Dempsey, James F; Palta, Jatinder R

2007-10-07

Optimization of equivalent uniform dose (EUD) in inverse planning for intensity-modulated radiation therapy (IMRT) prevents variation in radiobiological effect between different radiotherapy treatment plans, which is due to variation in the pattern of dose nonuniformity. For instance, the survival fraction of clonogens would be consistent with the prescription when the optimized EUD is equal to the prescribed EUD. One of the problems in the practical implementation of this approach is that the spatial dose distribution in EUD-based inverse planning would be underdetermined because an unlimited number of nonuniform dose distributions can be computed for a prescribed value of EUD. Together with ill-posedness of the underlying integral equation, this may significantly increase the dose nonuniformity. To optimize EUD and keep dose nonuniformity within reasonable limits, we implemented into an EUD-based objective function an additional criterion which ensures the smoothness of beam intensity functions. This approach is similar to the variational regularization technique which was previously studied for the dose-based least-squares optimization. We show that the variational regularization together with the L-curve criterion for the regularization parameter can significantly reduce dose nonuniformity in EUD-based inverse planning.

Analysis of data on radon monitoring and dose estimates for uranium mines

International Nuclear Information System (INIS)

Khan, A.H.; Srivastava, G.K.; Jha, Shankar; Sagar, D.V.

1994-01-01

Radon progeny are the major contributors to the radiation dose to uranium miners. Monitoring for radon and gamma radiation is an integral part of radiation protection in such mines. Data for equilibrium equivalent radon and the estimated mean annual doses are presented in this paper for Jaduguda uranium mine from 1986 to 1992. The 1992 data for Jaduguda and Bhatin mines are compared. The average annual effective dose for uranium miners is estimated at around 15.5 mSv. (author). 1 ref., 2 figs

Acceleration of intensity-modulated radiotherapy dose calculation by importance sampling of the calculation matrices

International Nuclear Information System (INIS)

Thieke, Christian; Nill, Simeon; Oelfke, Uwe; Bortfeld, Thomas

2002-01-01

In inverse planning for intensity-modulated radiotherapy, the dose calculation is a crucial element limiting both the maximum achievable plan quality and the speed of the optimization process. One way to integrate accurate dose calculation algorithms into inverse planning is to precalculate the dose contribution of each beam element to each voxel for unit fluence. These precalculated values are stored in a big dose calculation matrix. Then the dose calculation during the iterative optimization process consists merely of matrix look-up and multiplication with the actual fluence values. However, because the dose calculation matrix can become very large, this ansatz requires a lot of computer memory and is still very time consuming, making it not practical for clinical routine without further modifications. In this work we present a new method to significantly reduce the number of entries in the dose calculation matrix. The method utilizes the fact that a photon pencil beam has a rapid radial dose falloff, and has very small dose values for the most part. In this low-dose part of the pencil beam, the dose contribution to a voxel is only integrated into the dose calculation matrix with a certain probability. Normalization with the reciprocal of this probability preserves the total energy, even though many matrix elements are omitted. Three probability distributions were tested to find the most accurate one for a given memory size. The sampling method is compared with the use of a fully filled matrix and with the well-known method of just cutting off the pencil beam at a certain lateral distance. A clinical example of a head and neck case is presented. It turns out that a sampled dose calculation matrix with only 1/3 of the entries of the fully filled matrix does not sacrifice the quality of the resulting plans, whereby the cutoff method results in a suboptimal treatment plan

A dose assessment for a U.S. nuclear test site -- Bikini Atoll

International Nuclear Information System (INIS)

Robison, W.L.; Bogen, K.T.; Conrado, C.L.

1993-07-01

On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. Here the authors provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island. The unique composition of coral soil greatly alters the relative contribution of cesium-137 and strontium-90 to the total estimated dose relative to expectations based on North American and European soils. Cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The estimated maximum annual effective dose is 4.4 mSv y -1 when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 10 cSv, 14 cSv, and 16 cSv, respectively. An analysis of interindividual variability in 0- to 30-y expected integral dose indicates that 95% of Bikini residents would have expected doses within a factor of 3.4 above and 4.8 below the population-average value. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be ±35% of its expected value. The authors have evaluated various countermeasures to reduce 137 Cs in food crops. Treatment with potassium reduces the uptake of 137 Cs into food crops, and therefore the ingestion dose, to less than 10% of pretreatment levels and has essentially no negative environmental consequences

Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

Energy Technology Data Exchange (ETDEWEB)

Sumida, Iori, E-mail: sumida@radonc.med.osaka-u.ac.jp [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yoshikawa, Nobuhiko; Yamada, Yuji [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Suzuki, Osamu; Seo, Yuji [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Isohashi, Fumiaki [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Yoshioka, Yasuo [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Ogawa, Kazuhiko [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan)

2015-07-15

Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.

Radiation response of high speed CMOS integrated circuits

International Nuclear Information System (INIS)

Yue, H.; Davison, D.; Jennings, R.F.; Lothongkam, P.; Rinerson, D.; Wyland, D.

1987-01-01

This paper studies the total dose and dose rate radiation response of the FCT family of high speed CMOS integrated circuits. Data taken on the devices is used to establish the dominant failure modes, and this data is further analyzed using one-sided tolerance factors for normal distribution statistical analysis

Dose rate effect from the relationship between ICRU rectal dose and local control rate in intracavitary radiotherapy for carcinoma of the uterine cervix. Six fraction HDR and three-fraction LDR in three weeks

International Nuclear Information System (INIS)

Jingu, Kenichi; Akita, Yuzou; Ohmagari, Jyunichi

2001-01-01

The dose rate effect, low dose rate radiotherapy (LDR)/high dose rate radiotherapy (HDR), was calculated using the isoeffect ICRU rectal dose by intracavitary radiotherapy (ICRT) for uterine cervix cancer. The subjects analyzed consisted of 78 LDR and 74 HDR patients whose ICRU rectal dose could be calculated and whose local control as stage II/III cases could be evaluated. The point A dose in ICRT was 45-55 Gy/3 fractions/3 weeks for LDR and 30 Gy/6 fractions/3 weeks for HDR. The dose effect relationships associated with local control at each whole pelvis external radiation dose were calculated using the double integration method and Probit analysis, and the 50% and 90% local control ICRU rectal doses were calculated from this relationship. Finally, the dose rate effect LDR/HDR was determined from 50% and 90% local control doses. The dose rate effect calculated from the 50% local control dose was 1.24 and that from the 90% local control dose was 1.14. (author)

Assessment of Patients Radiation Dose During Interventional Radiological Procedure in PPUKM

International Nuclear Information System (INIS)

Mohd Khalid Matori; Husaini Salleh; Muhammad Jamal Muhammad Isa

2014-01-01

Interventional Radiology (IR) is a relatively new subspecialty of radiology. It is subspecialty where minimally invasive procedures are performed under radiological guidance using X-ray. This procedure can deliver high radiation doses compared with other radiological method due to long screening time. Because of these it is important to determine radiation doses received by patients undergoing IR procedures. It is to ensure that the dose is within the range deemed to be saved. A total of 128 patients undergoing IR procedures in PPUKM between 2012 and 2013 were study retrospectively. Dose area product (DAP) meter were used to measure the integral dose for the whole procedures. Mean kerma-area products for abdomen, head, pelvis, and thorax were 243.1, 107.3, 39.05 and 45.7 Gycm 2 , respectively. This study may provide the useful information which can be use to establish baseline patient dose data for dose optimizing study and carried out a recommendation on effective method of patient dose reduction during IR procedures. A more detail results of this study are presented in this paper. (author)

Analytical probabilistic proton dose calculation and range uncertainties

Science.gov (United States)

Bangert, M.; Hennig, P.; Oelfke, U.

2014-03-01

We introduce the concept of analytical probabilistic modeling (APM) to calculate the mean and the standard deviation of intensity-modulated proton dose distributions under the influence of range uncertainties in closed form. For APM, range uncertainties are modeled with a multivariate Normal distribution p(z) over the radiological depths z. A pencil beam algorithm that parameterizes the proton depth dose d(z) with a weighted superposition of ten Gaussians is used. Hence, the integrals ∫ dz p(z) d(z) and ∫ dz p(z) d(z)2 required for the calculation of the expected value and standard deviation of the dose remain analytically tractable and can be efficiently evaluated. The means μk, widths δk, and weights ωk of the Gaussian components parameterizing the depth dose curves are found with least squares fits for all available proton ranges. We observe less than 0.3% average deviation of the Gaussian parameterizations from the original proton depth dose curves. Consequently, APM yields high accuracy estimates for the expected value and standard deviation of intensity-modulated proton dose distributions for two dimensional test cases. APM can accommodate arbitrary correlation models and account for the different nature of random and systematic errors in fractionated radiation therapy. Beneficial applications of APM in robust planning are feasible.

Dose estimation for paediatric cranial computed tomography

International Nuclear Information System (INIS)

Curci Daros, K.A.; Bitelli Medeiros, R.; Curci Daros, K.A.; Oliveira Echeimberg, J. de

2006-01-01

In the last ten years, the number of paediatric computed tomography (CT) scans have increased worldwide, contributing to higher population radiation dose. Technique diversification in paediatrics and different CT equipment technologies have led to various exposure levels complicating precise evaluation of doses and operational conditions necessary for good quality images. The objective of this study was to establish a quantitative relationship between absorbed dose and cranial region in children up to 6 years old undergoing CT exams. Methods: X-ray was measured on the cranial surface of 64 patients undergoing CT using thermoluminescent (T.L.) dosimeters. Forty T.L.D.100 thermoluminescent dosimeters (T.L.D.) were evenly distributed on each patients skin surface along the sagittal axis. Measurements were performed in facial regions exposed to scatter radiation and in the supratentorial and posterior fossa regions, submitted to primary radiation. T.L.D. were calibrated for 120 kV X-ray over the acrylic phantom. T.L. measurements were made with a Harshaw 4000 system. Patient mean T.L. readings were determined for position, pi, of T.L.D. and normalized to the maximum supratentorial reading. From integrating the linear T.L. density function (?) resulting from radiation distribution in each of the three exposed regions, dose fraction was determined in the region of interest, along with total dose under the technical conditions used in that specific exam protocol. For each T.L.D. position along the patient cranium, there were n T.L. measurements with 2% uncertainty due to T.L. reader, and 5% due to thermal treatment of dosimeters. Also, mean T.L. readings and their uncertainties were calculated for each patient at each position, p. Results: Mean linear T.L. density for the region exposed to secondary radiation defined by position, 0.3≤p≤6 cm, was ρ((p)=7.9(4)x10 -2 +7(5)x10 -5 p 4.5(4) cm -1 ; exposed to primary X-ray for the posterior fossa region defined by position

Dose rate constants for new dose quantities

International Nuclear Information System (INIS)

Tschurlovits, M.; Daverda, G.; Leitner, A.

1992-01-01

Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)

Effects of low dose radiation and epigenetic regulation

International Nuclear Information System (INIS)

Jiao Benzheng; Ma Shumei; Yi Heqing; Kong Dejuan; Zhao Guangtong; Gao Lin; Liu Xiaodong

2010-01-01

Purpose: To conclude the relationship between epigenetics regulation and radiation responses, especially in low-dose area. Methods: The literature was examined for papers related to the topics of DNA methylation, histone modifications, chromatin remodeling and non-coding RNA modulation in low-dose radiation responses. Results: DNA methylation and radiation can regulate reciprocally, especially in low-dose radiation responses. The relationship between histone methylation and radiation mainly exists in the high-dose radiation area; histone deacetylase (HDAC) inhibitors show a promising application to enhance radiation sensitivity, no matter whether in low-dose or high-dose areas; the connection between γ-H2AX and LDR has been remained unknown, although γ-H2AX has been shown no radiation sensitivities with 1-15 Gy irradiation; histone ubiquitination play an important role in DNA damage repair mechanism. Moreover, chromatin remodeling has an integral role in DSB repair and the chromatin response, in general, may be precede DNA end resection. Finally, the effect of radiation on miRNA expression seems to vary according to cell type, radiation dose, and post-irradiation time point. Conclusion: Although the advance of epigenetic regulation on radiation responses, which we are managing to elucidate in this review, has been concluded, there are many questions and blind blots deserved to investigated, especially in low-dose radiation area. However, as progress on epigenetics, we believe that many new elements will be identified in the low-dose radiation responses which may put new sights into the mechanisms of radiation responses and radiotherapy. (authors)

Assessment of ambient gamma dose rate around a prospective uranium mining area of South India - A comparative study of dose by direct methods and soil radioactivity measurements

Science.gov (United States)

Karunakara, N.; Yashodhara, I.; Sudeep Kumara, K.; Tripathi, R. M.; Menon, S. N.; Kadam, S.; Chougaonkar, M. P.

Indoor and outdoor gamma dose rates were evaluated around a prospective uranium mining region - Gogi, South India through (i) direct measurements using a GM based gamma dose survey meter, (ii) integrated measurement days using CaSO4:Dy based thermo luminescent dosimeters (TLDs), and (iii) analyses of 273 soil samples for 226Ra, 232Th, and 40K activity concentration using HPGe gamma spectrometry. The geometric mean values of indoor and outdoor gamma dose rates were 104 nGy h-1 and 97 nGy h-1, respectively with an indoor to outdoor dose ratio of 1.09. The gamma dose rates and activity concentrations of 226Ra, 232Th, and 40K varied significantly within a small area due to the highly localized mineralization of the elements. Correlation study showed that the dose estimated from the soil radioactivity is better correlated with that measured directly using the portable survey meter, when compared to that obtained from TLDs. This study showed that in a region having localized mineralization in situ measurements using dose survey meter provide better representative values of gamma dose rates.

Parameters used in the environmental pathways (DESCARTES) and radiological dose (CIDER) modules of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC) for the air pathway

Energy Technology Data Exchange (ETDEWEB)

Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

1992-09-01

This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site since 1944. This work is being done by staff at Battelle, Pacific Northwest Laboratories (Battelle) under a contract with the Centers for Disease Control (CDC) with technical direction provided by an independent Technical Steering Panel (TSP). The objective of this report is to-document the environmental accumulation and dose-assessment parameters that will be used to estimate the impacts of past Hanford Site airborne releases. During 1993, dose estimates made by staff at Battelle will be used by the Fred Hutchinson Cancer Research Center as part of the Hanford Thyroid Disease Study (HTDS). This document contains information on parameters that are specific to the airborne release of the radionuclide iodine-131. Future versions of this document will include parameter information pertinent to other pathways and radionuclides.

Parameters used in the environmental pathways (DESCARTES) and radiological dose (CIDER) modules of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC) for the air pathway

International Nuclear Information System (INIS)

Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

1992-09-01

This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site since 1944. This work is being done by staff at Battelle, Pacific Northwest Laboratories (Battelle) under a contract with the Centers for Disease Control (CDC) with technical direction provided by an independent Technical Steering Panel (TSP). The objective of this report is to-document the environmental accumulation and dose-assessment parameters that will be used to estimate the impacts of past Hanford Site airborne releases. During 1993, dose estimates made by staff at Battelle will be used by the Fred Hutchinson Cancer Research Center as part of the Hanford Thyroid Disease Study (HTDS). This document contains information on parameters that are specific to the airborne release of the radionuclide iodine-131. Future versions of this document will include parameter information pertinent to other pathways and radionuclides

Islet oxygen consumption rate (OCR) dose predicts insulin independence for first clinical islet allotransplants

Science.gov (United States)

Kitzmann, JP; O’Gorman, D; Kin, T; Gruessner, AC; Senior, P; Imes, S; Gruessner, RW; Shapiro, AMJ; Papas, KK

2014-01-01

Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx. PMID:25131089

SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

Energy Technology Data Exchange (ETDEWEB)

Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

2016-06-15

Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

International Nuclear Information System (INIS)

Ganesan, B; Prakasarao, A; Singaravelu, G; Palraj, T; Rai, R

2016-01-01

Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

[Evaluation of Organ Dose Estimation from Indices of CT Dose Using Dose Index Registry].

Science.gov (United States)

Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

Direct measurement of each patient organ dose from computed tomography (CT) is not possible. Most methods to estimate patient organ dose is using Monte Carlo simulation with dedicated software. However, dedicated software is too expensive for small scale hospitals. Not every hospital can estimate organ dose with dedicated software. The purpose of this study was to evaluate the simple method of organ dose estimation using some common indices of CT dose. The Monte Carlo simulation software Radimetrics (Bayer) was used for calculating organ dose and analysis relationship between indices of CT dose and organ dose. Multidetector CT scanners were compared with those from two manufactures (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). Using stored patient data from Radimetrics, the relationships between indices of CT dose and organ dose were indicated as each formula for estimating organ dose. The accuracy of estimation method of organ dose was compared with the results of Monte Carlo simulation using the Bland-Altman plots. In the results, SSDE was the feasible index for estimation organ dose in almost organs because it reflected each patient size. The differences of organ dose between estimation and simulation were within 23%. In conclusion, our estimation method of organ dose using indices of CT dose is convenient for clinical with accuracy.

Microdosimetric approach for lung dose assessments

International Nuclear Information System (INIS)

Hofmann, W.; Steinhausler, F.; Pohl, E.; Bernroider, G.

1980-01-01

In the macroscopic region the term ''organ dose'' is related to an uniform energy deposition within a homogeneous biological target. Considering the lung, inhaled radioactive nuclides, however, show a significant non-uniform distribution pattern throughout the respiratory tract. For the calculation of deposition and clearance of inhaled alpha-emitting radionuclides within different regions of this organ, a detailed compartment model, based on the Weibel model A was developed. Since biological effects (e.g. lung cancer initiation) are primarily caused at the cellular level, the interaction of alpha particles with different types of cells of the lung tissue was studied. The basic approach is to superimpose alpha particle tracks on magnified images of randomly selected tissue slices, simulating alpha emitting sources. Particle tracks are generated by means of a specially developed computer program and used as input data for an on-line electronic image analyzer (Quantimet-720). Using adaptive pattern recognition methods the different cells in the lung tissue can be identified and their distribution within the whole organ determined. This microdosimetric method is applied to soluble radon decay products as well as to insoluble, highly localized, plutonium particles. For a defined microdistribution of alpha emitters, the resulting dose, integrated over all cellular dose values, is compared to the compartmental doses of the ICRP lung model. Furthermore this methodology is also applicable to other organs and tissues of the human body for dose calculations in practical health physics. (author)

Real-world healthcare utilization in asthma patients using albuterol sulfate inhalation aerosol (ProAir® HFA with and without integrated dose counters

Directory of Open Access Journals (Sweden)

Kerwin EM

2017-05-01

Full Text Available Edward M Kerwin,1 Thomas J Ferro,2 Rinat Ariely,3 Debra E Irwin,4 Ruchir Parikh3 1Clinical Trials Division, Clinical Research Institute of Southern Oregon, PC, Medford, OR, 2Global Medical Affairs, 3Global Health Economics and Outcome Research, Teva Pharmaceuticals, Frazer, PA, 4Outcomes Research, Truven Health Analytics, Durham, NC, USA Background: Accurate tracking of the administered dose of asthma rescue inhalers is critical for optimal disease management and is related to reductions in rates of unscheduled health care utilization in asthma patients. There are few published data on the real-world impact of rescue inhalers with integrated dose counters (IDCs on health care resource utilization (HRU for asthma patients. This study evaluates HRU among users of ProAir® hydrofluoroalkane (HFA (albuterol sulfate inhalation aerosol, with IDC versus without IDC, in asthma patients.Methods: This was a retrospective administrative claims study of asthma patients receiving a new prescription for albuterol inhalation aerosol without IDC during 2 years (January 2011–December 2012 or with IDC during the first full year after IDC implementation in the USA (July 2013–July 2014. Six months of continuous enrollment with medical and prescription drug benefits were required before and after the first prescription during the study period. Data on respiratory-related hospitalizations and emergency department (ED visits were collected during the follow-up period.Results: A total of 135,305 (32% patients used albuterol inhalation aerosol with IDC, and 287,243 (68% patients received albuterol inhalation aerosol without IDC. After adjusting for baseline confounding factors, the odds ratio (OR for experiencing a respiratory-related hospitalization (OR=0.92; 95% confidence interval [CI] 0.88–0.96 or ED visit (OR=0.92; 95% CI 0.90–0.94 was significantly lower among patients using albuterol inhalation aerosol with IDC versus without IDC.Conclusion: In a real

Evaluation of dose delivered to critical organs during pituitary radiation therapy

International Nuclear Information System (INIS)

Awoda, Marwa Elrashied Mohammed

2017-12-01

The selection of an appropriate energy in radiation therapy for tumor and the delivery adequate dose to the tumors to be treated, is very important during the radiation treatment planning. Also the dose received to critical organs surrounding the tumor has be considered. In addition, validation of treatment plan quality is important, so the purpose of this study was to evaluate the effect of teletherapy cobalt and 6MV linac energies on dose distribution for the pituitary gland tumors and dose delivered to critical organs surrounding the tumor. 10 patients with pituitary adenocarcinomas were selected. For treatment plans with three field technique, verdes and two lateral fields, were used. For the therapeutic area, five organs left and right eye lens left and right optic never and chasms and brain stem, were considered as Organ at risk (OARS). Several physical indices for for planning target volume (PTV) and the organs at risk 9 (OARS) as means dose (MD). 95%, dose (D950), 5% dose (D5) and normal tissue dose (NTID), were calculated, and the homogeneity index and conformity index were also two other evaluation parameters have been taken into account. The comparative evaluation was based on dose volume histogram ( DVH) analysis for both energies plans. After performing the treatment planning with two different energies the dose received to critical organs and dose distribution in PTV were studied. Results showed that the difference between the integral dose received to OARs with Co-60 and 6-MV linac respectively, 2.16±1.48, 1.85±1.55 for Lt eye lens. 3.01±2.52, 1.89±2.09 for Rt eye lens, 18.5±10.97, 19.43±10.65 for Lt optic nerve and chasms, 15.86±11.30, 17.44±15.73 for Rt optic nerve and chasms and 24.03±13.68, 23.77±16.64 for Brain stem case showed higher integral dose for linac than Co-60 than due to using the 6-MV energy as an open field with no beam modifiers such MLCs or shielding blocks. Eventually, it found that using of 6-MV linac provides better

Neutron absorbed dose in a pacemaker CMOS

International Nuclear Information System (INIS)

Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L.

2012-01-01

The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10 -17 Gy per neutron emitted by the source. (Author)

Neutron absorbed dose in a pacemaker CMOS

Energy Technology Data Exchange (ETDEWEB)

Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2012-06-15

The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

Computerized x-ray dose-monitoring system

International Nuclear Information System (INIS)

Hummel, R.H.; Wesenberg, R.L.; Amundson, G.M.

1985-01-01

An x-ray dose-monitoring system using a small digital computer is described. Initially, and for every 6 months afterward, the system is calibrated using an exposure meter. For each exposure, the computer receives values of x-ray technique and beam geometry from the x-ray generator through a specially designed electronic interface. Then, by means of calibration data, entrance exposure, area exposure product, and integral dose are obtained and printed for each patient examined. The overall accuracy of the system is better than +/-20%. Operation is semiautomatic, requiring minimum operator intervention. Over 2000 patients have been monitored with the device. Because the system is computer-based, it offers the opportunity for statistical analysis of the data base created, as the results for each patient are stored on computer disk

Measurement of radiation dose in dental radiology

International Nuclear Information System (INIS)

Helmrot, E.; Carlsson, G. A.

2005-01-01

Patient dose audit is an important tool for quality control and it is important to have a well-defined and easy to use method for dose measurements. In dental radiology, the most commonly used dose parameters for the setting of diagnostic reference levels (DRLs) are the entrance surface air kerma (ESAK) for intraoral examinations and dose width product (DWP) for panoramic examinations. DWP is the air kerma at the front side of the secondary collimator integrated over the collimator width and an exposure cycle. ESAK or DWP is usually measured in the absence of the patient but with the same settings of tube voltage (kV), tube current (mA) and exposure time as with the patient present. Neither of these methods is easy to use, and, in addition, DWP is not a risk related quantity. A better method of monitoring patient dose would be to use a dose area product (DAP) meter for all types of dental examinations. In this study, measurements with a DAP meter are reported for intraoral and panoramic examinations. The DWP is also measured with a pencil ionisation chamber and the product of DWP and the height H (DWP x H) of the secondary collimator (measured using film) was compared to DAP. The results show that it is feasible to measure DAP using a DAP meter for both intraoral and panoramic examinations. The DAP is therefore recommended for the setting of DRLs. (authors)

Internal dose estimation by bio-assay techniques

International Nuclear Information System (INIS)

Sawant, Pramilla D.

2016-01-01

Radiation exposure, both external and internal, can occur to radiation workers during the operation of various nuclear fuel cycle facilities and radiation facilities. The assessment of radiation doses to workers, routinely or potentially exposed to radiation, through intake of radionuclide is an integral part of the radiation protection programme. Internal dose is the radiation exposure that results from the intake of radioactive materials into the body by inhalation, ingestion, absorption through the skin or via wounds. Assessment of radiation doses arising from the intake of radioactive material by the workers is termed as internal exposure assessment. Unlike external exposure, internal exposure cannot be measured directly. Its evaluation is based on the calculation of the intake of radionuclide either from direct measurements (e.g, external monitoring of whole body or of specific organs and tissues) or indirect measurements (e.g. radioactivity in urine, faeces, breath or samples from the working environment) (ICRP Pub. 78, 1997 and NRPB-W60, 2004). Another method of internal dose assessment is based on the measurement of airborne radionuclides in the working areas of the facility and the worker's occupancy in those areas

Recent advances in understanding total-dose effects in bipolar transistors

International Nuclear Information System (INIS)

Schrimpf, R.D.

1996-01-01

Gain degradation in irradiated bipolar transistors can be a significant problem, particularly in linear integrated circuits. In many bipolar technologies, the degradation is greater for irradiation at low dose rates than it is for typical laboratory dose rates. Ionizing radiation causes the base current in bipolar transistors to increase, due to the presence of net positive charge in the oxides covering sensitive device areas and increases in surface recombination velocity. Understanding the mechanisms responsible for radiation-induced gain degradation in bipolar transistors is important in developing appropriate hardness assurance methods. This paper reviews recent modeling and experimental work, with the emphasis on low-dose-rate effects. A promising hardness assurance method based on irradiation at elevated temperatures is described

Ingestion dosimetry for assessment of individual dose to the population in HBRA

International Nuclear Information System (INIS)

Jojo, P.J.; Pereira, Christa E.; Chaougaonkar, M.P.

2012-05-01

Epidemiological studies on the population residing in the HBRA in Kerala is of considerable interest from the point of view of understanding the effects of low and chronic radiation exposures on the health of human population. The scope of these studies includes the simultaneous and time integrated measurements of both inhalation dose and external gamma dose due to environmental radiation, which are useful in the analysis of epidemiological studies. While the doses due to external gamma radiation and inhalation can be measured with a reasonable accuracy for an individual, measurement of ingestion dose for the same is quite difficult. In this research project, the radioactivity contents of the food items most commonly used by the population in the region is analysed and then the ingestion dose is estimated using standardized methodologies. (author)

EcoDoses. Improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2004

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Sven P.; Isaksson, M.; Nilsson, Elisabeth (and others)

2005-07-01

The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The present report sums up the work performed in the second phase of the project. The main topics in 2004 have been: (i) A continuation of previous work with a better approach for estimating global fallout on a regional or national scale, based on a correlation between precipitation and deposition rates. (ii) Fur-ther extension of the EcoDoses milk database. Estimation of effective ecological half lives of {sup 137}Cs in cows milk focussing on suitable post-Chernobyl time-series. Modelling integrated transfer of {sup 13}7{sup C}s to cow's milk from Nordic countries. (iii) Determination of effective ecological half lives for fresh water fish from Nordic lakes. (iv) Investigate ra-dioecological sensitivity for Nordic populations. (v) Food-chain modelling using the Eco-sys-model, which is the underlying food- and dose-module in several computerised deci-sion-making systems. (au)

EcoDoses. Improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2004

International Nuclear Information System (INIS)

Nielsen, Sven P.; Isaksson, M.; Nilsson, Elisabeth

2005-07-01

The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The present report sums up the work performed in the second phase of the project. The main topics in 2004 have been: (i) A continuation of previous work with a better approach for estimating global fallout on a regional or national scale, based on a correlation between precipitation and deposition rates. (ii) Fur-ther extension of the EcoDoses milk database. Estimation of effective ecological half lives of 137 Cs in cows milk focussing on suitable post-Chernobyl time-series. Modelling integrated transfer of 13 7 C s to cow's milk from Nordic countries. (iii) Determination of effective ecological half lives for fresh water fish from Nordic lakes. (iv) Investigate ra-dioecological sensitivity for Nordic populations. (v) Food-chain modelling using the Eco-sys-model, which is the underlying food- and dose-module in several computerised deci-sion-making systems. (au)

Dose sculpting with generalized equivalent uniform dose

International Nuclear Information System (INIS)

Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

2005-01-01

With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

Measurements of cosmic-ray doses in commercial airline cabins

International Nuclear Information System (INIS)

Okano, M.; Fujitaka, K.; Izumo, K.

1996-01-01

Cosmic radiation doses which aircrew and air passengers receive in airplanes have been calling attention in many countries especially in the last decade. In this relation, various types of information had been reported on cosmic radiation intensity. In Japan, the cosmic radiation intensity had been measured in commercial airline cabins as well as chartered flights. While the intensity depends on altitude, geomagnetic latitude (or cutoff rigidity), and temporal variation of the solar activity, their doses are often speculated based on paper records on airflights combined with the intensity-altitude relationship. In this study, however, efforts were made to estimate more realistic integrated doses in airline cabins based on actual on-board measurements which had been conducted several dozens of times in each year (e.g., 45 times in 1994 and 27 times in 1995). (author)

Fluorecence modulated radiotherapy with integrated segmentation to optimization

International Nuclear Information System (INIS)

Baer, W.; Alber, M.; Nuesslin, F.

2003-01-01

On the basis of two clinical cases, we present fluence-modulated radiotherapy with a sequencer integrated into the optimization of our treatment-planning software HYPERION. In each case, we achieved simple relations for the dependence of the total number of segments on the complexity of the sequencing, as well as for the dependence of the dose-distribution quality on the number of segments. For both clinical cases, it was possible to obtain treatment plans that complied with the clinical demands on dose distribution and number of segments. Also, compared to the widespread concept of equidistant steps, our method of sequencing with fluence steps of variable size led to a significant reduction of the number of segments, while maintaining the quality of the dose distribution. Our findings substantiate the value of the integration of the sequencer into the optimization for the clinical efficiency of IMRT [de

Extent of radiosensitization by the PARP inhibitor olaparib depends on its dose, the radiation dose and the integrity of the homologous recombination pathway of tumor cells

NARCIS (Netherlands)

Verhagen, Caroline V. M.; de Haan, Rosemarie; Hageman, Floor; Oostendorp, Tim P. D.; Carli, Annalisa L. E.; O'Connor, Mark J.; Jonkers, Jos; Verheij, Marcel; van den Brekel, Michiel W.; Vens, Conchita

2015-01-01

The PARP inhibitor olaparib is currently tested in clinical phase 1 trials to define safe dose levels in combination with RT. However, certain clinically relevant insights are still lacking. Here we test, while comparing to single agent activity, the olaparib dose and genetic background dependence

Implementation of spot scanning dose optimization and dose calculation for helium ions in Hyperion

Energy Technology Data Exchange (ETDEWEB)

Fuchs, Hermann, E-mail: hermann.fuchs@meduniwien.ac.at [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090, Austria and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Alber, Markus [Department for Oncology, Aarhus University Hospital, Aarhus 8000 (Denmark); Schreiner, Thomas [PEG MedAustron, Wiener Neustadt 2700 (Austria); Georg, Dietmar [Department of Radiation Oncology, Division of Medical Radiation Physics, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Vienna 1090 (Austria); Comprehensive Cancer Center, Medical University of Vienna/AKH Vienna, Vienna 1090 (Austria)

2015-09-15

Purpose: Helium ions ({sup 4}He) may supplement current particle beam therapy strategies as they possess advantages in physical dose distribution over protons. To assess potential clinical advantages, a dose calculation module accounting for relative biological effectiveness (RBE) was developed and integrated into the treatment planning system Hyperion. Methods: Current knowledge on RBE of {sup 4}He together with linear energy transfer considerations motivated an empirical depth-dependent “zonal” RBE model. In the plateau region, a RBE of 1.0 was assumed, followed by an increasing RBE up to 2.8 at the Bragg-peak region, which was then kept constant over the fragmentation tail. To account for a variable proton RBE, the same model concept was also applied to protons with a maximum RBE of 1.6. Both RBE models were added to a previously developed pencil beam algorithm for physical dose calculation and included into the treatment planning system Hyperion. The implementation was validated against Monte Carlo simulations within a water phantom using γ-index evaluation. The potential benefits of {sup 4}He based treatment plans were explored in a preliminary treatment planning comparison (against protons) for four treatment sites, i.e., a prostate, a base-of-skull, a pediatric, and a head-and-neck tumor case. Separate treatment plans taking into account physical dose calculation only or using biological modeling were created for protons and {sup 4}He. Results: Comparison of Monte Carlo and Hyperion calculated doses resulted in a γ{sub mean} of 0.3, with 3.4% of the values above 1 and γ{sub 1%} of 1.5 and better. Treatment plan evaluation showed comparable planning target volume coverage for both particles, with slightly increased coverage for {sup 4}He. Organ at risk (OAR) doses were generally reduced using {sup 4}He, some by more than to 30%. Improvements of {sup 4}He over protons were more pronounced for treatment plans taking biological effects into account. All

Integrated nuclear and radiation protection systems

International Nuclear Information System (INIS)

Oprea, I.; Oprea, M.; Stoica, V.; Cerga, V.; Pirvu, V.; Badea, E.

1993-01-01

A multifunctional radiation monitoring equipment, flexible and capable to meet virtually environmental radiation monitoring, activity measurement and computational requirements, for nuclear laboratories has been designed. It can be used as a radiation protection system, for radionuclide measurement in isotope laboratories, nuclear technology, health physics and nuclear medicine, nuclear power stations and nuclear industry. The equipment is able to measure, transmit and record gamma dose rate and isotope activities. Other parameters and functions are optionally available, such as: self-contained alarm level, system self-test, dose integrator, syringe volume calculation for a given dose corrected for decay, calibration factor, 99 Mo assays performing and background subtraction

Application of Electron Dose Kernels to account for heterogeneities in voxelized phantoms

International Nuclear Information System (INIS)

Al-Basheer, A. K.; Sjoden, G. E.; Ghita, M.; Bolch, W.

2009-01-01

In this paper, we present work on the application of the Electron Dose Kernel discrete ordinates method (EDK-S N ) to compute doses and account for material heterogeneities using high energy external photon beam irradiations in voxelized human phantoms. EDKs are pre-computed using photon pencil 'beamlets' that lead to dose delivery in tissue using highly converged Monte Carlo. Coupling the EDKs to accumulate dose scaled by integral photon fluences computed using S N methods in dose driving voxels (DDVs) allows for the full charged particle physics computed dose to be accumulated throughout the voxelized phantom, and is the basis of the EDK-S N method, which is fully parallelized. For material heterogeneities, a density scaling correction factor is required to yield good agreement. In a fully voxelized phantom, all doses were in agreement with those determined by independent Monte Carlo computations. We are continuing to expand upon the development of this robust approach for rapid and accurate determination of whole body and out of field organ doses due to high energy x-ray beams. (authors)

Concepts for dose determination in flat-detector CT

International Nuclear Information System (INIS)

Kyriakou, Yiannis; Deak, Paul; Langner, Oliver; Kalender, Willi A

2008-01-01

Flat-detector computed tomography (FD-CT) scanners provide large irradiation fields of typically 200 mm in the cranio-caudal direction. In consequence, dose assessment according to the current definition of the computed tomography dose index CTDI L=100mm , where L is the integration length, would demand larger ionization chambers and phantoms which do not appear practical. We investigated the usefulness of the CTDI concept and practical dosimetry approaches for FD-CT by measurements and Monte Carlo (MC) simulations. An MC simulation tool (ImpactMC, VAMP GmbH, Erlangen, Germany) was used to assess the dose characteristics and was calibrated with measurements of air kerma. For validation purposes measurements were performed on an Axiom Artis C-arm system (Siemens Medical Solutions, Forchheim, Germany) equipped with a flat detector of 40 cm x 30 cm. The dose was assessed for 70 kV and 125 kV in cylindrical PMMA phantoms of 160 mm and 320 mm diameter with a varying phantom length from 150 to 900 mm. MC simulation results were compared to the values obtained with a calibrated ionization chambers of 100 mm and 250 mm length and to thermoluminesence (TLD) dose profiles. The MCs simulations were used to calculate the efficiency of the CTDI L determination with respect to the desired CTDI ∞ . Both the MC simulation results and the dose distributions obtained by MC simulation were in very good agreement with the CTDI measurements and with the reference TLD profiles, respectively, to within 5%. Standard CTDI phantoms which have a z-extent of 150 mm underestimate the dose at the center by up to 55%, whereas a z-extent of ≥600 mm appears to be sufficient for FD-CT; the baseline value of the respective profile was within 1% to the reference baseline. As expected, the measurements with ionization chambers of 100 mm and 250 mm offer a limited accuracy, whereas an increased integration length of ≥600 mm appeared to be necessary to approximate CTDI ∞ in within 1%. MC

Biphasic dose responses in biology, toxicology and medicine: Accounting for their generalizability and quantitative features

International Nuclear Information System (INIS)

Calabrese, Edward J.

2013-01-01

The most common quantitative feature of the hormetic-biphasic dose response is its modest stimulatory response which at maximum is only 30–60% greater than control values, an observation that is consistently independent of biological model, level of organization (i.e., cell, organ or individual), endpoint measured, chemical/physical agent studied, or mechanism. This quantitative feature suggests an underlying “upstream” mechanism common across biological systems, therefore basic and general. Hormetic dose response relationships represent an estimate of the peak performance of integrative biological processes that are allometrically based. Hormetic responses reflect both direct stimulatory or overcompensation responses to damage induced by relatively low doses of chemical or physical agents. The integration of the hormetic dose response within an allometric framework provides, for the first time, an explanation for both the generality and the quantitative features of the hormetic dose response. -- Highlights: •The hormetic stimulation is at maximum 30–60% greater than control responses. •Hormesis is a measure of biological performance and plasticity. •The hormetic response is evolutionary based and highly generalizable. -- This paper provides a biologically based explanation for the generalizability/quantitative features of the hormetic dose response, representing a fundamental contribution to the field

Dose estimation for paediatric cranial computed tomography

Energy Technology Data Exchange (ETDEWEB)

Curci Daros, K.A.; Bitelli Medeiros, R. [Sao Paulo Univ. Federal (Brazil); Curci Daros, K.A.; Oliveira Echeimberg, J. de [Centro Univ. Sao Camilo, Sao Paulo (Brazil)

2006-07-01

In the last ten years, the number of paediatric computed tomography (CT) scans have increased worldwide, contributing to higher population radiation dose. Technique diversification in paediatrics and different CT equipment technologies have led to various exposure levels complicating precise evaluation of doses and operational conditions necessary for good quality images. The objective of this study was to establish a quantitative relationship between absorbed dose and cranial region in children up to 6 years old undergoing CT exams. Methods: X-ray was measured on the cranial surface of 64 patients undergoing CT using thermoluminescent (T.L.) dosimeters. Forty T.L.D.100 thermoluminescent dosimeters (T.L.D.) were evenly distributed on each patients skin surface along the sagittal axis. Measurements were performed in facial regions exposed to scatter radiation and in the supratentorial and posterior fossa regions, submitted to primary radiation. T.L.D. were calibrated for 120 kV X-ray over the acrylic phantom. T.L. measurements were made with a Harshaw 4000 system. Patient mean T.L. readings were determined for position, pi, of T.L.D. and normalized to the maximum supratentorial reading. From integrating the linear T.L. density function (?) resulting from radiation distribution in each of the three exposed regions, dose fraction was determined in the region of interest, along with total dose under the technical conditions used in that specific exam protocol. For each T.L.D. position along the patient cranium, there were n T.L. measurements with 2% uncertainty due to T.L. reader, and 5% due to thermal treatment of dosimeters. Also, mean T.L. readings and their uncertainties were calculated for each patient at each position, p. Results: Mean linear T.L. density for the region exposed to secondary radiation defined by position, 0.3{<=}p{<=}6 cm, was {rho}((p)=7.9(4)x10{sup -2}+7(5)x10{sup -5}p{sup 4.5(4)} cm{sup -1}; exposed to primary X-ray for the posterior fossa

Parameters used in the environmental pathways and radiological dose modules (DESCARTES, CIDER, and CRD codes) of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC)

International Nuclear Information System (INIS)

Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

1994-05-01

This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site during the period of 1944 to 1992. This work is being done by staff at Battelle, Pacific Northwest Laboratories under a contract with the Centers for Disease Control and Prevention with technical direction provided by an independent Technical Steering Panel (TSP)

Parameters used in the environmental pathways and radiological dose modules (DESCARTES, CIDER, and CRD codes) of the Hanford Environmental Dose Reconstruction Integrated Codes (HEDRIC)

Energy Technology Data Exchange (ETDEWEB)

Snyder, S.F.; Farris, W.T.; Napier, B.A.; Ikenberry, T.A.; Gilbert, R.O.

1994-05-01

This letter report is a description of work performed for the Hanford Environmental Dose Reconstruction (HEDR) Project. The HEDR Project was established to estimate the radiation doses to individuals resulting from releases of radionuclides from the Hanford Site during the period of 1944 to 1992. This work is being done by staff at Battelle, Pacific Northwest Laboratories under a contract with the Centers for Disease Control and Prevention with technical direction provided by an independent Technical Steering Panel (TSP).

Extent of radiosensitization by the PARP inhibitor olaparib depends on its dose, the radiation dose and the integrity of the homologous recombination pathway of tumor cells

NARCIS (Netherlands)

Verhagen, C.V.M.; Haan, R. den; Hageman, F.; Oostendorp, T.P.; Carli, A.L.; O'Connor, M.J.; Jonkers, J.; Verheij, M.; Brekel, M.W. van den; Vens, C.

2015-01-01

BACKGROUND AND PURPOSE: The PARP inhibitor olaparib is currently tested in clinical phase 1 trials to define safe dose levels in combination with RT. However, certain clinically relevant insights are still lacking. Here we test, while comparing to single agent activity, the olaparib dose and genetic

Extent of radiosensitization by the PARP inhibitor olaparib depends on its dose, the radiation dose and the integrity of the homologous recombination pathway of tumor cells

NARCIS (Netherlands)

Verhagen, C.V.M.; de Haan, R.; Hageman, F.; Oostendorp, T.P.D.; Carli, A.L.E.; O'Connor, M.J.; Jonkers, J.; Verheij, M.; van den Brekel, M.W.; Vens, C.

2015-01-01

Background and purpose The PARP inhibitor olaparib is currently tested in clinical phase 1 trials to define safe dose levels in combination with RT. However, certain clinically relevant insights are still lacking. Here we test, while comparing to single agent activity, the olaparib dose and genetic

A method for describing the doses delivered by transmission x-ray computed tomography

International Nuclear Information System (INIS)

Shope, T.B.; Gagne, R.M.; Johnson, G.C.

1981-01-01

A method for describing the absorbed dose delivered by x-ray transmission computed tomography (CT) is proposed which provides a means to characterize the dose resulting from CT procedures consisting of a series of adjacent scans. The dose descriptor chosen is the average dose at several locations in the imaged volume of the central scan of the series. It is shown that this average dose, as defined, for locations in the central scan of the series can be obtained from the integral of the dose profile perpendicular to the scan plane at these same locations for a single scan. This method for estimating the average dose from a CT procedure has been evaluated as a function of the number of scans in the multiple scan procedure and location in the dosimetry phantom using single scan dose profiles obtained from five different types of CT systems. For the higher dose regions in the phantoms, the multiple scan dose descriptor derived from the single scan dose profiles overestimates the multiple scan average dose by no more than 10%, provided the procedure consists of at least eight scans

From personnel dose to personal dose

International Nuclear Information System (INIS)

Hoefert, M.; Raffnsoe, R.C.; Tuyn, J.W.N.; Wittekind, D.

1985-01-01

From following the development of personnel doses at CERN over the past six years it has become evident that work in areas of induced radioactivity is the principal cause of exposure. The results of photon dose measurements free-in-air and around a phantom are presented and discussed in the light of new quantities in individual monitoring. The importance of these results, with respect to the practical situation, is discussed and the problem of phantom size is mentioned. Finally, the results of dose measurements in the phantom are presented, since such information is important in cases where it becomes necessary to transform personnel doses into personal doses. (author)

Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

International Nuclear Information System (INIS)

Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

2010-01-01

The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice.

Science.gov (United States)

Ware, J H; Sanzari, J; Avery, S; Sayers, C; Krigsfeld, G; Nuth, M; Wan, X S; Rusek, A; Kennedy, A R

2010-09-01

The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

Population doses from terrestrial gamma exposure in China

International Nuclear Information System (INIS)

Ren, T.; Wang, Z.; Zhu, C.

1992-01-01

In order to estimate terrestrial gamma radiation exposure three nationwide surveys have been completed since 1981. The population-weighted outdoor and indoor arithmetic means of gamma dose rate based on momentary dose rate measurements using a NaI(Tl) environmental radiation meter and high-pressure ionisation chamber are, respectively, 80.3 nGy.h -1 and 120 nGy.h -1 . Based on integrating dose measurement using TLD CaSO 4 /Dy they are 67 nGy.h -1 and 89 nGy.h -1 respectively, and based on natural radionuclides concentrations in soil, determined by gamma spectroscopy analyses, they are 72.8 nGy.h -1 and 102 nGy.h -1 , respectively. These surveys were conducted independently by different groups. The best estimations of population-weighted gamma dose rates in China, based on all these surveys, would be 70 nGy.h -1 and 98 nGy.h -1 for outdoors and indoors, respectively. The annual average of effective dose equivalent is 0.56 mSv. These values are higher than the world averages estimated by UNSCEAR. The main reason is that the concentrations of 232 Th and 40 K in the soil of China are much higher than the world average estimated. (author)

Biosphere model for assessing doses from nuclear waste disposal

International Nuclear Information System (INIS)

Zach, R.; Amiro, B.D.; Davis, P.A.; Sheppard, S.C.; Szekeley, J.G.

1994-01-01

The biosphere model, BIOTRAC, for predicting long term nuclide concentrations and radiological doses from Canada's nuclear fuel waste disposal concept of a vault deep in plutonic rock of the Canadian Shield is presented. This generic, boreal zone biosphere model is based on scenario analysis and systems variability analysis using Monte Carlo simulation techniques. Conservatism is used to bridge uncertainties, even though this creates a small amount of extra nuclide mass. Environmental change over the very long assessment period is mainly handled through distributed parameter values. The dose receptors are a critical group of humans and four generic non-human target organisms. BIOTRAC includes six integrated submodels and it interfaces smoothly with a geosphere model. This interface includes a bedrock well. The geosphere model defines the discharge zones of deep groundwater where nuclides released from the vault enter the biosphere occupied by the dose receptors. The size of one of these zones is reduced when water is withdrawn from the bedrock well. Sensitivity analysis indicates 129 I is by far the most important radionuclide. Results also show bedrock-well water leads to higher doses to man than lake water, but the former doses decrease with the size of the critical group. Under comparable circumstances, doses to the non-human biota are greater than those for man

Estimating collective dose in nuclear facilities, with emphasis on the design process

International Nuclear Information System (INIS)

Cohen, S.; Mann, B.

1987-01-01

The report presents a more accurate, systematic method than has been available previously for predicting worker doses which might be incurred during routine and non-routine work in radioactive areas. Besides assisting regulators with an analysis of the ''potential impact on radiological exposures of facility employees'' now required under the new backfit rule (10 CFR 50.109c), this predictive model will also help licensees conserve dollars as well as dose because it can be employed very early in the engineering design phase of a modification, when adjustments can still be made easily to change orders. Such early estimates make good business sense because they will facilitate planning, labor loading, costing, resource and equipment scheduling, and overall coordination of both single and repetitive projects. Also, with the support of corporate management, radiation protection coordinators can introduce the model into training programs to acquaint design engineers and others with dose calculation techniques. The importance assigned by nuclear industry senior management to the principle of ALARA and the reduction of collective worker dose is measured, in large part, by demonstrated efforts to integrate the control of radiation exposure fully into the overall planning function of nuclear facility management. That integration will be fostered through the use of this approach

Integrated Inflammatory Stress (ITIS) Model

DEFF Research Database (Denmark)

Bangsgaard, Elisabeth O.; Hjorth, Poul G.; Olufsen, Mette S.

2017-01-01

maintains a long-term level of the stress hormone cortisol which is also anti-inflammatory. A new integrated model of the interaction between these two subsystems of the inflammatory system is proposed and coined the integrated inflammatory stress (ITIS) model. The coupling mechanisms describing....... A constant activation results in elevated levels of the variables in the model while a prolonged change of the oscillations in ACTH and cortisol concentrations is the most pronounced result of different LPS doses predicted by the model....

Dose calculation in eye brachytherapy with Ir-192 threads using the Sievert integral and corrected by attenuation and scattering with the Meisberg polynomials; Calculo de dosis en braquiterapia ocular con hilos de Ir-192 utilizando la integral de Sievert y cooregida por atenuacion y dispersion con los polinomios de Meisberg

Energy Technology Data Exchange (ETDEWEB)

Vivanco, M.G. Bernui de; Cardenas R, A. [Instituto Nacional de Enfermedades Neoplasicas, Universidad Nacional de Ingenieria, Av. Angamos No. 2520, Surquillo, Lima (Peru)]. e-mail: gisellebdv@hotmail.com

2006-07-01

The ocular brachytherapy many times unique alternative to conserve the visual organ in patients of ocular cancer, one comes carrying out in the National Institute of Neoplastic Illnesses (INEN) using threads of Iridium 192; those which, they are placed in radial form on the interior surface of a spherical cap of gold of 18 K; the cap remains in the eye until reaching the prescribed dose by the doctor. The main objective of this work is to be able to calculate in a correct and practical way the one time that the treatment of ocular brachytherapy should last to reach the dose prescribed by the doctor. To reach this objective I use the Sievert integral corrected by attenuation effects and scattering (Meisberg polynomials); calculating it by the Simpson method. In the calculations by means of the Sievert integral doesn't take into account the scattering produced by the gold cap neither the variation of the constant of frequency of exposure with the distance. The calculations by means of Sievert integral are compared with those obtained using the Monte Carlo Penelope simulation code, where it is observed that they agree at distances of the surface of the cap greater or equal to 2mm. (Author)

Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project

Energy Technology Data Exchange (ETDEWEB)

Anderson, D.M.; Bates, D.J.; Marsh, T.L.

1993-07-01

This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

International Nuclear Information System (INIS)

Sandilos, Panagiotis; Baras, Panagiotis; Georgiou, Evangelos; Dardoufas, Konstantinos; Karaiskos, Pantelis; Papagiannis, Panagiotis; Paschalis, Theodoros; Tatsis, Elias; Torrens, Michael; Vlahos, Lampros

2006-01-01

Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an 192 Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications

Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

Energy Technology Data Exchange (ETDEWEB)

Sandilos, Panagiotis [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Baras, Panagiotis [Philips Hellas Medical Systems, 44 Kifissias Ave., Maroussi 151 25, Athens (Greece); Georgiou, Evangelos [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Dardoufas, Konstantinos [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Karaiskos, Pantelis [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece)]. E-mail: p.karaiskos@hygeia.gr; Papagiannis, Panagiotis [Physics Department, Nuclear and Particle Physics Section, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Paschalis, Theodoros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Tatsis, Elias [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Torrens, Michael [Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Vlahos, Lampros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece)

2006-12-20

Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an {sup 192}Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications.

Sun-Induced Changes in Stratum Corneum Function Are Gender and Dose Dependent in a Chinese Population

Science.gov (United States)

Liu, Z.; Fluhr, J.W.; Song, S.P.; Sun, Z.; Wang, H.; Shi, Y.J.; Elias, P.M.; Man, M.-Q.

2010-01-01

Previous studies have demonstrated that UVB radiation changes the epidermal permeability barrier and stratum corneum (SC) hydration. It is well known that sun exposure causes erythema, sunburn and melanoma. However, whether daily sun exposure alters SC integrity and epidermal permeability barrier function is largely unknown, especially in Chinese subjects. In the present study, we assess the SC integrity, SC hydration and epidermal permeability barrier function following various doses of sun exposure. A total of 258 subjects (124 males and 134 females) aged 18–50 years were enrolled. A multifunctional skin physiology monitor (Courage & Khazaka MPA5) was used to measure SC hydration and transepidermal water loss (TEWL) on the forearms. In males, basal TEWL was higher with higher doses of sun exposure than with lower doses and control, whereas in females, basal TEWL was higher with lower doses of sun exposure than with higher doses and control. In the group with higher doses of sun exposure, TEWL in females was significantly lower than that in males. The barrier recovery was faster in females than in males in both control and lower-dose groups. In both males and females, barrier recovery was delayed with higher doses of sun exposure. In males, sun exposure did not alter SC hydration, while in females SC hydration was lower with lower doses of sun exposure as compared with control and higher doses of sun exposure. These results demonstrated that sun-induced changes in SC function and SC hydration vary with gender and the extent of sun exposure. PMID:20571289

Final Technical Report. A critical evaluation of patent doses in screening mammography

International Nuclear Information System (INIS)

Hintenlang, David E.

2004-01-01

This project was designed to develop tools that would permit an accurate assessment of the patient doses that are received in screening mammography, and to subsequently demonstrate those tools to perform an objective evaluation of patient doses. The project also provides an educational component through the integration of multiple aspects of applied radiological engineering to provide students with realistic applications of many of the theoretical principles that are studied as part of their graduate curriculum

On-line MR imaging for dose validation of abdominal radiotherapy

International Nuclear Information System (INIS)

Glitzner, M; Crijns, S P M; De Senneville, B Denis; Kontaxis, C; Prins, F M; Lagendijk, J J W; Raaymakers, B W

2015-01-01

For quality assurance and adaptive radiotherapy, validation of the actual delivered dose is crucial.Intrafractional anatomy changes cannot be captured satisfactorily during treatment with hitherto available imaging modalitites. Consequently, dose calculations are based on the assumption of static anatomy throughout the treatment. However, intra- and interfraction anatomy is dynamic and changes can be significant.In this paper, we investigate the use of an MR-linac as a dose tracking modality for the validation of treatments in abdominal targets where both respiratory and long-term peristaltic and drift motion occur.The on-line MR imaging capability of the modality provides the means to perform respiratory gating of both delivery and acquisition yielding a model-free respiratory motion management under free breathing conditions.In parallel to the treatment, the volumetric patient anatomy was captured and used to calculate the applied dose. Subsequently, the individual doses were warped back to the planning grid to obtain the actual dose accumulated over the entire treatment duration. Ultimately, the planned dose was validated by comparison with the accumulated dose.Representative for a site subject to breathing modulation, two kidney cases (25 Gy target dose) demonstrated the working principle on volunteer data and simulated delivery. The proposed workflow successfully showed its ability to track local dosimetric changes. Integration of the on-line anatomy information could reveal local dose variations  −2.3–1.5 Gy in the target volume of a volunteer dataset. In the adjacent organs at risk, high local dose errors ranging from  −2.5 to 1.9 Gy could be traced back. (paper)

On-line MR imaging for dose validation of abdominal radiotherapy

Science.gov (United States)

Glitzner, M.; Crijns, S. P. M.; de Senneville, B. Denis; Kontaxis, C.; Prins, F. M.; Lagendijk, J. J. W.; Raaymakers, B. W.

2015-11-01

For quality assurance and adaptive radiotherapy, validation of the actual delivered dose is crucial. Intrafractional anatomy changes cannot be captured satisfactorily during treatment with hitherto available imaging modalitites. Consequently, dose calculations are based on the assumption of static anatomy throughout the treatment. However, intra- and interfraction anatomy is dynamic and changes can be significant. In this paper, we investigate the use of an MR-linac as a dose tracking modality for the validation of treatments in abdominal targets where both respiratory and long-term peristaltic and drift motion occur. The on-line MR imaging capability of the modality provides the means to perform respiratory gating of both delivery and acquisition yielding a model-free respiratory motion management under free breathing conditions. In parallel to the treatment, the volumetric patient anatomy was captured and used to calculate the applied dose. Subsequently, the individual doses were warped back to the planning grid to obtain the actual dose accumulated over the entire treatment duration. Ultimately, the planned dose was validated by comparison with the accumulated dose. Representative for a site subject to breathing modulation, two kidney cases (25 Gy target dose) demonstrated the working principle on volunteer data and simulated delivery. The proposed workflow successfully showed its ability to track local dosimetric changes. Integration of the on-line anatomy information could reveal local dose variations  -2.3-1.5 Gy in the target volume of a volunteer dataset. In the adjacent organs at risk, high local dose errors ranging from  -2.5 to 1.9 Gy could be traced back.

Modelling the Influence of Shielding on Physical and Biological Organ Doses

CERN Document Server

Ballarini, Francesca; Ferrari, Alfredo; Ottolenghi, Andrea; Pelliccioni, Maurizio; Scannicchio, Domenico

2002-01-01

Distributions of "physical" and "biological" dose in different organs were calculated by coupling the FLUKA MC transport code with a geometrical human phantom inserted into a shielding box of variable shape, thickness and material. While the expression "physical dose" refers to the amount of deposited energy per unit mass (in Gy), "biological dose" was modelled with "Complex Lesions" (CL), clustered DNA strand breaks calculated in a previous work based on "event-by-event" track-structure simulations. The yields of complex lesions per cell and per unit dose were calculated for different radiation types and energies, and integrated into a version of FLUKA modified for this purpose, allowing us to estimate the effects of mixed fields. As an initial test simulation, the phantom was inserted into an aluminium parallelepiped and was isotropically irradiated with 500 MeV protons. Dose distributions were calculated for different values of the shielding thickness. The results were found to be organ-dependent. In most ...

The sensitivity of calculated doses to critical assumptions for the offsite consequences of nuclear power reactor accidents

International Nuclear Information System (INIS)

Moeller, M.P.; Scherpelz, R.I.; Desrosiers, A.E.

1982-01-01

This work analyzes the sensitivity of calculated doses to critical assumptions for offsite consequences following a PWR-2 accident at a nuclear power reactor. The calculations include three radiation dose pathways: internal dose resulting from inhalation, external doses from exposure to the plume, and external doses from exposure to contaminated ground. The critical parameters are the time period of integration for internal dose commitment and the duration of residence on contaminated ground. The data indicate the calculated offsite whole body dose will vary by as much as 600% depending upon the parameters assumed. When offsite radiation doses determine the size of emergency planning zones, this uncertainty has significant effect upon the resources allocated to emergency preparedness

PROMPT DOSE ANALYSIS FOR THE NATIONAL IGNITION FACILITY

International Nuclear Information System (INIS)

Khater, H.; Dauffy, L.; Sitaraman, S.; Brereton, S.

2008-01-01

Detailed 3-D modeling of the NIF facility is developed to accurately understand the prompt radiation environment within NIF. Prompt dose values are calculated for different phases of NIF operation. Results of the analysis were used to determine the final thicknesses of the Target Bay (TB) and secondary doors as well as the required shield thicknesses for all unused penetrations. Integrated dose values at different locations within the facility are needed to formulate the personnel access requirements within different parts of the facility. The conclusions of this presentation are: (1) The current NIF facility model includes all important features of the Target Chamber, shielding system, and building configuration; (2) All shielding requirements for Phase I operation are met; (3) Negligible dose values (a fraction of mrem) are expected in normally occupied areas during Phase I; (4) In preparation for the Ignition Campaign and Phase IV of operation, all primary and secondary shield doors will be installed; (5) Unused utility penetrations in the Target Bay and Switchyard walls (∼50%) will be shielded by 1 foot thick concrete to reduce prompt dose inside and outside the NIF facility; (6) During Phase IV, a 20 MJ shot will produce acceptable dose levels in the occupied areas as well as at the nearest site boundary; (7) A comprehensive radiation monitoring plan will be put in place to monitor dose values at large number of locations; and (8) Results of the dose monitoring will be used to modify personnel access requirements if needed

Biological UV-doses and the effect on an ozone layer depletion

International Nuclear Information System (INIS)

Dahlback, A.; Henriksen, T.

1988-08-01

Effective UV-doses were calculated based on the integrated product of the biological action spectrum and the solar radiation. The calculations included absorption and scattering of UV-radiation in the atmosphere, both for normal ozone conditions as well as for a depleted ozone layer. The effective annual UV-dose increases by approximately 4% per degree of latitude towards the equator. An ozone depletion of 1% increases the annual UV-dose by approximately 1% at 60 o N. A large depletion of 50% over Scandinavia (60 o N) would give this region an effective UV-dose similar to that obtained, with normal ozone conditions, at a latitude of 40 o N (California or the Mediterranean countries). The Antarctic ozone hole increases the annual UV-dose by 20 to 25% which is a similar increase as that attained by moving 5 to 6 degrees of latitude nearer the equator. The annual UV-dose on higher latitudes is mainly determined by the summer values of ozone. Both the ozone values and the effective UV-doses vary from one year to another (within ±4%). No positive or negative trend is observed for Scandinavia from 1978 to 1988

Integrative Radiation Biology

Energy Technology Data Exchange (ETDEWEB)

Barcellos-Hoff, Mary Helen [New York University School of Medicine, NY (United States)

2015-02-27

We plan to study tissue-level mechanisms important to human breast radiation carcinogenesis. We propose that the cell biology of irradiated tissues reveals a coordinated multicellular damage response program in which individual cell contributions are primarily directed towards suppression of carcinogenesis and reestablishment of homeostasis. We identified transforming growth factor β1 (TGFβ) as a pivotal signal. Notably, we have discovered that TGFβ suppresses genomic instability by controlling the intrinsic DNA damage response and centrosome integrity. However, TGFβ also mediates disruption of microenvironment interactions, which drive epithelial to mesenchymal transition in irradiated human mammary epithelial cells. This apparent paradox of positive and negative controls by TGFβ is the topic of the present proposal. First, we postulate that these phenotypes manifest differentially following fractionated or chronic exposures; second, that the interactions of multiple cell types in tissues modify the responses evident in this single cell type culture models. The goals are to: 1) study the effect of low dose rate and fractionated radiation exposure in combination with TGFβ on the irradiated phenotype and genomic instability of non-malignant human epithelial cells; and 2) determine whether stromal-epithelial interactions suppress the irradiated phenotype in cell culture and the humanized mammary mouse model. These data will be used to 3) develop a systems biology model that integrates radiation effects across multiple levels of tissue organization and time. Modeling multicellular radiation responses coordinated via extracellular signaling could have a significant impact on the extrapolation of human health risks from high dose to low dose/rate radiation exposure.

Passive Rn dose meters - measuring methods appropriate for large measurement series

International Nuclear Information System (INIS)

Urban, M.; Kiefer, H.

1985-01-01

Passive integrating measuring methods can be classified in several groups by their functioning principle, e.g. spray chambers or open chambers with nuclear trace detectors or TL detectors, open detectors, activated carbon dose meters with or without TL detectors. According to the functioning principle, only radon or radon and fission products can be detected. The lecture gives a survey of the present state of development of passive Rn dose meters. By the example of the Ra dose meter developed at Karlsruhe which was used in inquiry measurements carried out in Germany, Switzerland, the Netherlands, Belgium and Austria, etching technology, estimation of measuring uncertainties, reproducibility and fading behaviour shall be discussed. (orig./HP) [de

Dose assessments for SFR 1

International Nuclear Information System (INIS)

Bergstroem, Ulla; Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la

2008-05-01

Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

Dose assessments for SFR 1

Energy Technology Data Exchange (ETDEWEB)

Bergstroem, Ulla (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la (Facilia AB, Bromma (Sweden))

2008-06-15

Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

Methods for calculating dose conversion coefficients for terrestrial and aquatic biota

International Nuclear Information System (INIS)

Ulanovsky, A.; Proehl, G.; Gomez-Ros, J.M.

2008-01-01

Plants and animals may be exposed to ionizing radiation from radionuclides in the environment. This paper describes the underlying data and assumptions to assess doses to biota due to internal and external exposure for a wide range of masses and shapes living in various habitats. A dosimetric module is implemented which is a user-friendly and flexible possibility to assess dose conversion coefficients for aquatic and terrestrial biota. The dose conversion coefficients have been derived for internal and various external exposure scenarios. The dosimetric model is linked to radionuclide decay and emission database, compatible with the ICRP Publication 38, thus providing a capability to compute dose conversion coefficients for any nuclide from the database and its daughter nuclides. The dosimetric module has been integrated into the ERICA Tool, but it can also be used as a stand-alone version

Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

Directory of Open Access Journals (Sweden)

Lukas Ebner

2014-01-01

Full Text Available Objective:The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP and an iterative reconstruction (IR algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP, SOMATOM Definition Flash (IR, and SOMATOM Definition Edge (ICD and IR. Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP with FBP for the average chest CT was 308 mGycm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGycm ± 68.8 (P = 0.0001. Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGycm ± 54.5 (P = 0.033. The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048. Overall contrast-to-noise ratio (CNR improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

Transport calculations of. gamma. -ray flux density and dose rate about implantable californium-252 sources

Energy Technology Data Exchange (ETDEWEB)

Shapiro, A; Lin, B I [Cincinnati Univ., Ohio (USA). Dept. of Chemical and Nuclear Engineering; Windham, J P; Kereiakes, J G

1976-07-01

..gamma.. flux density and dose rate distributions have been calculated about implantable californium-252 sources for an infinite tissue medium. Point source flux densities as a function of energy and position were obtained from a discrete-ordinates calculation, and the flux densities were multiplied by their corresponding kerma factors and added to obtain point source dose rates. The point dose rates were integrated over the line source to obtain line dose rates. Container attenuation was accounted for by evaluating the point dose rate as a function of platinum thickness. Both primary and secondary flux densities and dose rates are presented. The agreement with an independent Monte Carlo calculation was excellent. The data presented should be useful for the design of new source configurations.

Feasibility of optimizing the dose distribution in lung tumors using fluorine-18-fluorodeoxyglucose positron emission tomography and single photon emission computed tomography guided dose prescriptions

International Nuclear Information System (INIS)

Das, S.K.; Miften, M.M.; Zhou, S.; Bell, M.; Munley, M.T.; Whiddon, C.S.; Craciunescu, O.; Baydush, A.H.; Wong, T.; Rosenman, J.G.; Dewhirst, M.W.; Marks, L.B.

2004-01-01

The information provided by functional images may be used to guide radiotherapy planning by identifying regions that require higher radiation dose. In this work we investigate the dosimetric feasibility of delivering dose to lung tumors in proportion to the fluorine-18-fluorodeoxyglucose activity distribution from positron emission tomography (FDG-PET). The rationale for delivering dose in proportion to the tumor FDG-PET activity distribution is based on studies showing that FDG uptake is correlated to tumor cell proliferation rate, which is shown to imply that this dose delivery strategy is theoretically capable of providing the same duration of local control at all voxels in tumor. Target dose delivery was constrained by single photon emission computed tomography (SPECT) maps of normal lung perfusion, which restricted irradiation of highly perfused lung and imposed dose-function constraints. Dose-volume constraints were imposed on all other critical structures. All dose-volume/function constraints were considered to be soft, i.e., critical structure doses corresponding to volume/function constraint levels were minimized while satisfying the target prescription, thus permitting critical structure doses to minimally exceed dose constraint levels. An intensity modulation optimization methodology was developed to deliver this radiation, and applied to two lung cancer patients. Dosimetric feasibility was assessed by comparing spatially normalized dose-volume histograms from the nonuniform dose prescription (FDG-PET proportional) to those from a uniform dose prescription with equivalent tumor integral dose. In both patients, the optimization was capable of delivering the nonuniform target prescription with the same ease as the uniform target prescription, despite SPECT restrictions that effectively diverted dose from high to low perfused normal lung. In one patient, both prescriptions incurred similar critical structure dosages, below dose-volume/function limits

Beta particle dose rates to micro-organisms in soil

International Nuclear Information System (INIS)

Kabir, M.; Spiers, F.W.; Iinuma, Takeshi.

1977-01-01

Studies were made to estimate the beta-particle dose rates to micro-organisms of various sizes in soil. The small insects and organisms living in soil are constantly exposed to beta-radiation arising from naturally occuring radionuclides in soil as in this case no overlying tissue shields them. The technique of measuring beta-particle dose rate consisted of using of a thin plastic scintillator to measure the pulse height distribution as the beta particle traverses the scintillator. The integrated response was determined by the number and size of the photomultiplier pulses. From the data of soil analyses it was estimated that typically about 29% of the beta particles emitted per gm. of soil were contributed by the U/Ra series, 21% by the Th series and about 50% by potassium. By combining the individual spectra of these three radionuclides in the proportion found in a typical soil, a resultant spectrum was computed representing the energy distribution of the beta particles. The dose rate received by micro-organisms of different shape and size in soil was derived from the equilibrium dose rates combined with a 'Geometrical Factor' of the organisms. For small organisms, the dose rates did not vary between the spherical and cylindrical types, but in the case of larger organisms, the dose rates were found to be greater for the spherical types of the same diameter. (auth.)

Normal tissue dose-effect models in biological dose optimisation

International Nuclear Information System (INIS)

Alber, M.

2008-01-01

Sophisticated radiotherapy techniques like intensity modulated radiotherapy with photons and protons rely on numerical dose optimisation. The evaluation of normal tissue dose distributions that deviate significantly from the common clinical routine and also the mathematical expression of desirable properties of a dose distribution is difficult. In essence, a dose evaluation model for normal tissues has to express the tissue specific volume effect. A formalism of local dose effect measures is presented, which can be applied to serial and parallel responding tissues as well as target volumes and physical dose penalties. These models allow a transparent description of the volume effect and an efficient control over the optimum dose distribution. They can be linked to normal tissue complication probability models and the equivalent uniform dose concept. In clinical applications, they provide a means to standardize normal tissue doses in the face of inevitable anatomical differences between patients and a vastly increased freedom to shape the dose, without being overly limiting like sets of dose-volume constraints. (orig.)

Population doses from terrestrial gamma exposure in China

Energy Technology Data Exchange (ETDEWEB)

Ren, T.; Wang, Z.; Zhu, C. (Ministry of Public Health, Beijing, BJ (China))

1992-01-01

In order to estimate terrestrial gamma radiation exposure three nationwide surveys have been completed since 1981. The population-weighted outdoor and indoor arithmetic means of gamma dose rate based on momentary dose rate measurements using a NaI(Tl) environmental radiation meter and high-pressure ionisation chamber are, respectively, 80.3 nGy.h[sup -1] and 120 nGy.h[sup -1]. Based on integrating dose measurement using TLD CaSO[sub 4]/Dy they are 67 nGy.h[sup -1] and 89 nGy.h[sup -1] respectively, and based on natural radionuclides concentrations in soil, determined by gamma spectroscopy analyses, they are 72.8 nGy.h[sup -1] and 102 nGy.h[sup -1], respectively. These surveys were conducted independently by different groups. The best estimations of population-weighted gamma dose rates in China, based on all these surveys, would be 70 nGy.h[sup -1] and 98 nGy.h[sup -1] for outdoors and indoors, respectively. The annual average of effective dose equivalent is 0.56 mSv. These values are higher than the world averages estimated by UNSCEAR. The main reason is that the concentrations of [sup 232]Th and [sup 40]K in the soil of China are much higher than the world average estimated. (author).

Radiological dose assessment from the operation of Daeduk nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Choi, Young Gil [Korea Atomic Energy Research Institute, Taejon (Korea)

2000-02-01

The objective of this project is to assure the public acceptance for nuclear facilities, and the environmental safety from the operation of Daeduk nuclear facilities, such as HANARO research reactor, nuclear fuel processing facilities and others. For identifying the integrity of their facilities, the maximum individual doses at the site boundary and on the areas with high population density were assessed. Also, the collective doses within radius 80 km from the site were assessed. The radiation impacts for residents around the site from the operation of Daeduk nuclear facilities in 1999 were neglectable. 8 refs., 10 figs., 27 tabs. (Author)

Decision Support System for Optimized Herbicide Dose in Spring Barley

DEFF Research Database (Denmark)

Sønderskov, Mette; Kudsk, Per; Mathiassen, Solvejg K

2014-01-01

Crop Protection Online (CPO) is a decision support system, which integrates decision algorithms quantifying the requirement for weed control and a herbicide dose model. CPO was designed to be used by advisors and farmers to optimize the choice of herbicide and dose. The recommendations from CPO...... as the Treatment Frequency Index (TFI)) compared to a high level of required weed control. The observations indicated that the current level of weed control required is robust for a range of weed scenarios. Weed plant numbers 3 wk after spraying indicated that the growth of the weed species were inhibited...

Probabilistic Dose Assessment from SB-LOCA Accident in Ujung Lemahabang Using TMI-2 Source Term

Directory of Open Access Journals (Sweden)

Sunarko

2017-01-01

Full Text Available Probabilistic dose assessment and mapping for nuclear accident condition are performed for Ujung Lemahabang site in Muria Peninsula region in Indonesia. Source term is obtained from Three-Mile Island unit 2 (TMI-2 PWR-type SB-LOCA reactor accident inverse modeling. Effluent consisted of Xe-133, Kr-88, I-131, and Cs-137 released from a 50 m stack. Lagrangian Particle Dispersion Method (LPDM and 3-dimensional mass-consistent wind field are employed to obtain surface-level time-integrated air concentration and spatial distribution of ground-level total dose in dry condition. Site-specific meteorological data is obtained from hourly records obtained during the Site Feasibility Study period in Ujung Lemahabang. Effluent is released from a height of 50 meters in uniform rate during a 6-hour period and the dose is integrated during this period in a neutrally stable atmospheric condition. Maximum dose noted is below regulatory limit of 1 mSv and radioactive plume is spread mostly to the W-SW inland and to N-NE from the proposed plant to Java Sea. This paper has demonstrated for the first time a probabilistic analysis method for assessing possible spatial dose distribution, a hypothetical release, and a set of meteorological data for Ujung Lemahabang region.

Estimation of 1945 to 1957 food consumption. Hanford Environmental Dose Reconstruction Project: Draft

Energy Technology Data Exchange (ETDEWEB)

Anderson, D.M.; Bates, D.J.; Marsh, T.L.

1993-03-01

This report details the methods used and the results of the study on the estimated historic levels of food consumption by individuals in the Hanford Environmental Dose Reconstruction (HEDR) study area from 1945--1957. This period includes the time of highest releases from Hanford and is the period for which data are being collected in the Hanford Thyroid Disease Study. These estimates provide the food-consumption inputs for the HEDR database of individual diets. This database will be an input file in the Hanford Environmental Dose Reconstruction Integrated Code (HEDRIC) computer model that will be used to calculate the radiation dose. The report focuses on fresh milk, eggs, lettuce, and spinach. These foods were chosen because they have been found to be significant contributors to radiation dose based on the Technical Steering Panel dose decision level.

An updated dose assesment for resettlement options at Bikini atoll - A US nuclear test site

International Nuclear Information System (INIS)

Robison, W.L.; Bogen, K.T.; Conrado, C.L.

1997-01-01

There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radio nuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as part of our continuing research and monitoring program that began in 1978. The unique composition of coral soil greatly alters the relative contribution of 137 Cs and 90 Sr to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, 137 Cs produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1999. The estimated maximum annual effective dose for current island conditions is 4.0 mSv when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 91 mSv, 130 mSv, and 150 mSv, respectively. A detailed uncertainty analysis for these dose estimates is presented in a companion paper in this issue. We have evaluated various countermeasures to reduce 137 Cs in food crops. Treatment with potassium reduces the uptake of 137 Cs into food crops, and therefore the ingestion dose, to about 5 % of pretreatment levels and has essentially no negative environmental consequences. We have calculated the dose for the rehabilitation scenario where the top 40 cm of soil is removed in the housing and village area, and the rest of the island is treated with potassium fertilizer; the maximum annual effective dose is 0.41 mSv and the 30-, 50-, and 70-y integral effective doses are 9.8 mSv, 14 mSv, and 16 mSv, respectively. 44 refs., 3 figs., 11 tabs

NASA Space Radiation Program Integrative Risk Model Toolkit

Science.gov (United States)

Kim, Myung-Hee Y.; Hu, Shaowen; Plante, Ianik; Ponomarev, Artem L.; Sandridge, Chris

2015-01-01

NASA Space Radiation Program Element scientists have been actively involved in development of an integrative risk models toolkit that includes models for acute radiation risk and organ dose projection (ARRBOD), NASA space radiation cancer risk projection (NSCR), hemocyte dose estimation (HemoDose), GCR event-based risk model code (GERMcode), and relativistic ion tracks (RITRACKS), NASA radiation track image (NASARTI), and the On-Line Tool for the Assessment of Radiation in Space (OLTARIS). This session will introduce the components of the risk toolkit with opportunity for hands on demonstrations. The brief descriptions of each tools are: ARRBOD for Organ dose projection and acute radiation risk calculation from exposure to solar particle event; NSCR for Projection of cancer risk from exposure to space radiation; HemoDose for retrospective dose estimation by using multi-type blood cell counts; GERMcode for basic physical and biophysical properties for an ion beam, and biophysical and radiobiological properties for a beam transport to the target in the NASA Space Radiation Laboratory beam line; RITRACKS for simulation of heavy ion and delta-ray track structure, radiation chemistry, DNA structure and DNA damage at the molecular scale; NASARTI for modeling of the effects of space radiation on human cells and tissue by incorporating a physical model of tracks, cell nucleus, and DNA damage foci with image segmentation for the automated count; and OLTARIS, an integrated tool set utilizing HZETRN (High Charge and Energy Transport) intended to help scientists and engineers study the effects of space radiation on shielding materials, electronics, and biological systems.

Boron dose determination for BNCT using Fricke and EPR dosimetry

International Nuclear Information System (INIS)

Wielopolski, L.; Ciesielski, B.

1995-01-01

In Boron Neutron Capture Therapy (BNCT) the dominant dose delivered to the tumor is due to α and 7 Li charged particles resulting from a neutron capture by 10 B and is referred to herein as the boron dose. Boron dose is directly attributable to the following two independent factors, one boron concentration and the neutron capture energy dependent cross section of boron, and two the energy spectrum of the neutrons that interact with boron. The neutron energy distribution at a given point is dictated by the incident neutron energy distribution, the depth in tissue, geometrical factors such as beam size and patient's dimensions. To account for these factors can be accommodated by using Monte Carlo theoretical simulations. However, in conventional experimental BNCT dosimetry, e.g., using TLDs or ionization chambers, it is only possible to estimate the boron dose. To overcome some of the limitations in the conventional dosimetry, modifications in ferrous sulfate dosimetry (Fricke) and Electron Paramagnetic Resonance (EPR) dosimetry in alanine, enable to measure specifically boron dose in a mixed gamma neutron radiation fields. The boron dose, in either of the dosimeters, is obtained as a difference between measurements with boronated and unboronated dosimeters. Since boron participates directly in the measurements, the boron dosimetry reflects the true contribution, integral of the neutron energy spectrum with boron cross section, of the boron dose to the total dose. Both methods are well established and used extensively in dosimetry, they are presented briefly here

Graves' disease radioiodine-therapy: Choosing target absorbed doses for therapy planning

Energy Technology Data Exchange (ETDEWEB)

Willegaignon, J., E-mail: j.willegaignon@gmail.com; Sapienza, M. T.; Coura-Filho, G. B.; Buchpiguel, C. A. [Cancer Institute of São Paulo State (ICESP), Clinical Hospital, School of Medicine, University of São Paulo, São Paulo 01246-000 (Brazil); Nuclear Medicine Service, Department of Radiology, School of Medicine, University of São Paulo, Sao Paulo 01246-000 (Brazil); Watanabe, T. [Nuclear Medicine Service, Department of Radiology, School of Medicine, University of São Paulo, São Paulo 01246-000 (Brazil); Traino, A. C. [Unit of Medical Physics, Azienda Ospedaliero-Universitaria Pisana, Pisa 56126 (Italy)

2014-01-15

Purpose: The precise determination of organ mass (m{sub th}) and total number of disintegrations within the thyroid gland (A{sup ~}) are essential for thyroid absorbed-dose calculations for radioiodine therapy. Nevertheless, these parameters may vary according to the method employed for their estimation, thus introducing uncertainty in the estimated thyroid absorbed dose and in any dose–response relationship derived using such estimates. In consideration of these points, thyroid absorbed doses for Graves’ disease (GD) treatment planning were calculated using different approaches to estimating the m{sub th} and the A{sup ~}. Methods: Fifty patients were included in the study. Thyroid{sup 131}I uptake measurements were performed at 2, 6, 24, 48, 96, and 220 h postadministration of a tracer activity in order to estimate the effective half-time (T{sub eff}) of {sup 131}I in the thyroid; the thyroid cumulated activity was then estimated using the T{sub eff} thus determined or, alternatively, calculated by numeric integration of the measured time-activity data. Thyroid mass was estimated by ultrasonography (USG) and scintigraphy (SCTG). Absorbed doses were calculated with the OLINDA/EXM software. The relationships between thyroid absorbed dose and therapy response were evaluated at 3 months and 1 year after therapy. Results: The average ratio (±1 standard deviation) betweenm{sub th} estimated by SCTG and USG was 1.74 (±0.64) and that between A{sup ~} obtained by T{sub eff} and the integration of measured activity in the gland was 1.71 (±0.14). These differences affect the calculated absorbed dose. Overall, therapeutic success, corresponding to induction of durable hypothyroidism or euthyroidism, was achieved in 72% of all patients at 3 months and in 90% at 1 year. A therapeutic success rate of at least 95% was found in the group of patients receiving doses of 200 Gy (p = 0.0483) and 330 Gy (p = 0.0131) when m{sub th} was measured by either USG or SCTG and A

Improvement of Off-site Dose Assessment Code for Operating Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Kim, Juyub; Kim, Juyoul; Shin, Kwangyoung [FNC Technology Co. Ltd., Yongin (Korea, Republic of); You, Songjae; Moon, Jongyi [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2014-05-15

XOQDOQ code which calculates atmospheric Dispersion factor was included into INDAC also. A research on the improvement of off-site dose assessment system for an operating nuclear power plant was performed by KINS in 2011. As a result, following improvements were derived: - Separation of dose assessment for new and existing facilities - Update of food ingestion data - Consideration of multi-unit operation and so on In order to reflect the results, INDAC is under modification. INDAC is an integrated dose assessment code for an operating nuclear power plant and consists of three main modules: XOQDOQ, GASDOS and LIQDOS. The modules are under modification in order to improve the accuracy of assessment and usability. Assessment points for multi-unit release can be calculated through the improved code and the method on dose assessment for multi-unit release has been modified, so that the dose assessment result of multi-unit site becomes more realistic by relieving excessive conservatism. Finally, as the accuracy of calculation modules has been improved, the reliability of dose assessment result has been strengthened.

Dose distribution calculation for in-vivo X-ray fluorescence scanning

International Nuclear Information System (INIS)

Figueroa, R. G.; Lozano, E.; Valente, M.

2013-01-01

In-vivo X-ray fluorescence constitutes a useful and accurate technique, worldwide established for constituent elementary distribution assessment. Actually, concentration distributions of arbitrary user-selected elements can be achieved along sample surface with the aim of identifying and simultaneously quantifying every constituent element. The method is based on the use of a collimated X-ray beam reaching the sample. However, one common drawback for considering the application of this technique for routine clinical examinations was the lack of information about associated dose delivery. This work presents a complete study of the dose distribution resulting from an in-vivo X-ray fluorescence scanning for quantifying biohazard materials on human hands. Absorbed dose has been estimated by means of dosimetric models specifically developed to this aim. In addition, complete dose distributions have been obtained by means of full radiation transport calculations in based on stochastic Monte Carlo techniques. A dedicated subroutine has been developed using the Penelope 2008 main code also integrated with dedicated programs -Mat Lab supported- for 3 dimensional dose distribution visualization. The obtained results show very good agreement between approximate analytical models and full descriptions by means of Monte Carlo simulations. (Author)

Organ dose from inhaled radionuclides taking lull period into account

International Nuclear Information System (INIS)

Datta, S.

1982-01-01

The dosimetry of inhaled radionuclides is generally carried out in accordance with the lung model recommended by the ICRP Task Group on Lung Dynamics. The relevant expressions are integrated over a given period, assuming continuous inhalation in an atmosphere of constant aerosol concentration. Though for the same amount of intake the dose commitment is found to be independent of variations in the rate of intake, the dose determined over specific intervals of time, is influenced by it or by lull intervals therein. Formulae are developed to arrive at doses to different organs when the subject's intake is constant and continuous for 8 hours, followed by a lull period of 16 hours each day. Results are given for a number of radionuclides and are compared with values characteristic of continuous inhalation. It is observed that when exposure is assumed to be continuous the dose for the same intake of activity is underestimated as compared to the dose when lull period is taken into account. For working periods of 6 days and 30 days the underestimate ranges from 5%-20% and 0.6% to 4.5% respectively. (author)

Cosmic ray LET spectra and doses on board Cosmos-2044 biosatellite

International Nuclear Information System (INIS)

Dudkin, V.E.; Kovalev, E.E.; Potapov, Yu.V.

1992-01-01

Results of the experiments on board Cosmos-2044 (Biosatellite 9) are presented. Various nuclear track detectors (NTD) (dielectric, AgCl-based, nuclear emulsions) were used to obtain the LET spectra inside and outside the satellite. The spectra from the different NTDs have proved to be in general agreement. The results of LET spectra calculations using two different models are also presented. The resultant LET distributions are used to calculate the absorbed and equivalent doses and the orbit-averaged quality factors (QF) of the cosmic rays (CR). Absorbed dose rates inside (∼ 20 g cm -2 shielding) and outside (1 g cm -2 ) the spacecraft, omitting electrons, were found to be 4.8 and 8.6 mrad d -1 , respectively, while the corresponding equivalent doses were 8.8 and 19.7 mrem d -1 . The effects of the flight parameters on the total fluence of, and on the dose from, the CR particles are analyzed. Integral dose distributions of the detected particles are also determined. The LET values which separate absorbed and equivalent doses into 50% intervals are estimated. The CR-39 dielectric NTD is shown to detect 20-30% of the absorbed dose and 60-70% of the equivalent dose in the Cosmos-2044 orbit. The influence of solar activity phase on the magnitude of the CR flux is discussed. (author)

Patient Dose Considerations in Interventional Cardiology

International Nuclear Information System (INIS)

Ciraj-Bjelac, O.; Rafajlovic, S.; Arandjic, D.; Kosutic, D.

2011-01-01

Interventional cardiology procedures are classified as high-dose procedures, owing to increased risk for radiation skin injuries and stochastic effects, such as cancer. European MED Directive 97/43 requires special consideration and dose evaluation for this kind of procedures . Dose received by a patient, in general, depends on the radiological equipment, examination protocol, the way it is implemented, the patient's body weight and nature of disease. Long-term fluoroscopy of certain parts of the body, a significant body mass, high-value dose intensity, continuous rather than pulsed fluoroscopy, small focus-skin distance and repeated procedure on the same patient, are among the factors that can lead to radiation skin injuries. A particular challenge is the fact that the radiation damage of the skin is difficult to detect and connect to the previously conducted cardiologic procedures. The fact that such injuries do not have immediate manifestation is very often reason that many of them remain undetected. The purpose of this work is to assess the level of radiation dose to patients in percutaneous coronary interventions (PCI) and to investigate possibility for setting of a practical trigger value if dose quantities exceed certain levels in terms of dose descriptors available at display of interventional cardiology unit. Two dedicated interventional cardiology units in a large teaching cardiac centre (Clinical Centre of Serbia, Belgrade, Serbia) were included in the survey. Both rooms (D and F) were equipped with X-ray units of the identical model: Siemens Axiom Artis (Siemens, Erlangen, Germany) with the flat panel detector and integrated ionization chamber to measure air kerma-area product (P K A) and air kerma in international reference point (K I RP). Patient doses were assessed in terms of P K A, K I RP and maximum-skin dose (MSD). P K A and K I RP were assessed using a built-in, in situ calibrated dosimeters, while MSD was estimated using radiochromic films

Dose and dose rate monitor

International Nuclear Information System (INIS)

Novakova, O.; Ryba, J.; Slezak, V.; Svobodova, B.; Viererbl, L.

1984-10-01

The methods are discussea of measuring dose rate or dose using a scintillation counte. A plastic scintillator based on polystyrene with PBD and POPOP activators and coated with ZnS(Ag) was chosen for the projected monitor. The scintillators were cylindrical and spherical in shape and of different sizes; black polypropylene tubes were chosen as the best case for the probs. For the counter with different plastic scintillators, the statistical error 2σ for natural background was determined. For determining the suitable thickness of the ZnS(Ag) layer the energy dependence of the counter was measured. Radioisotopes 137 Cs, 241 Am and 109 Cd were chosen as radiation sources. The best suited ZnS(Ag) thickness was found to be 0.5 μm. Experiments were carried out to determine the directional dependence of the detector response and the signal to noise ratio. The temperature dependence of the detector response and its compensation were studied, as were the time stability and fatigue manifestations of the photomultiplier. The design of a laboratory prototype of a dose rate and dose monitor is described. Block diagrams are given of the various functional parts of the instrument. The designed instrument is easiiy portable, battery powered, measures dose rates from natural background in the range of five orders, i.e., 10 -2 to 10 3 nGy/s, and allows to determine a dose of up to 10 mGy. Accouracy of measurement in the energy range of 50 keV to 1 MeV is better than +-20%. (E.S.)

Area monitoring of ambient dose rates in parts of South-Western Nigeria using a GPS-integrated radiation survey meter

International Nuclear Information System (INIS)

Okeyode, I.C.; Rabiu, J.A.; Alatise, O.O.; Makinde, V.; Akinboro, F.G.; Mustapha, A.O.; Al-Azmi, D.

2017-01-01

A radiation monitoring system comprising a Geiger-Muller counter connected to a smart phone via Bluetooth was used for a dose rate survey in some parts of south-western Nigeria. The smart phone has the Geographical Positioning System, which provides the navigation information and saves it along with the dose rate data. A large number of data points was obtained that shows the dose rate distribution within the region. The results show that the ambient dose rates in the region range from 60 to 520 nSv -1 and showed a bias that is attributable to the influence of geology on the ambient radiation dose in the region. The geology influence was demonstrated by superimposing the dose rate plot and the geological map of the area. The potential applications of the device in determining baseline information and in area monitoring, e.g. for lost or abandoned sources, radioactive materials stockpiles, etc., were discussed in the article, particularly against the background of Nigeria's plan to develop its nuclear power program. (authors)

Integration of second cancer risk calculations in a radiotherapy treatment planning system

International Nuclear Information System (INIS)

Hartmann, M; Schneider, U

2014-01-01

Second cancer risk in patients, in particular in children, who were treated with radiotherapy is an important side effect. It should be minimized by selecting an appropriate treatment plan for the patient. The objectives of this study were to integrate a risk model for radiation induced cancer into a treatment planning system which allows to judge different treatment plans with regard to second cancer induction and to quantify the potential reduction in predicted risk. A model for radiation induced cancer including fractionation effects which is valid for doses in the radiotherapy range was integrated into a treatment planning system. From the three-dimensional (3D) dose distribution the 3D-risk equivalent dose (RED) was calculated on an organ specific basis. In addition to RED further risk coefficients like OED (organ equivalent dose), EAR (excess absolute risk) and LAR (lifetime attributable risk) are computed. A risk model for radiation induced cancer was successfully integrated in a treatment planning system. Several risk coefficients can be viewed and used to obtain critical situations were a plan can be optimised. Risk-volume-histograms and organ specific risks were calculated for different treatment plans and were used in combination with NTCP estimates for plan evaluation. It is concluded that the integration of second cancer risk estimates in a commercial treatment planning system is feasible. It can be used in addition to NTCP modelling for optimising treatment plans which result in the lowest possible second cancer risk for a patient.

Determination of organ doses and effective doses in radiooncology

International Nuclear Information System (INIS)

Roth, J.; Martinez, A.E.

2007-01-01

Background and Purpose: With an increasing chance of success in radiooncology, it is necessary to estimate the risk from radiation scatter to areas outside the target volume. The cancer risk from a radiation treatment can be estimated from the organ doses, allowing a somewhat limited effective dose to be estimated and compared. Material and Methods: The doses of the radiation-sensitive organs outside the target volume can be estimated with the aid of the PC program PERIDOSE developed by van der Giessen. The effective doses are determined according to the concept of ICRP, whereby the target volume and the associated organs related to it are not taken into consideration. Results: Organ doses outside the target volume are generally < 1% of the dose in the target volume. In some cases, however, they can be as high as 3%. The effective doses during radiotherapy are between 60 and 900 mSv, depending upon the specific target volume, the applied treatment technique, and the given dose in the ICRU point. Conclusion: For the estimation of the radiation risk, organ doses in radiooncology can be calculated with the aid of the PC program PERIDOSE. While evaluating the radiation risk after ICRP, for the calculation of the effective dose, the advanced age of many patients has to be considered to prevent that, e.g., the high gonad doses do not overestimate the effective dose. (orig.)

The estimation of effective doses using measurement of several relevant physical parameters from radon exposures

International Nuclear Information System (INIS)

Ridzikova, A; Fronka, A.; Maly, B.; Moucka, L.

2003-01-01

In the present investigation, we will be study the dose relevant factors from continual monitoring in real homes into account getting more accurate estimation of 222 Rn the effective dose. The dose relevant parameters include the radon concentration, the equilibrium factor (f), the fraction (fp) of unattached radon decay products and real time occupancy people in home. The result of the measurement are the time courses of radon concentration that are based on estimation effective doses together with assessment of the real time occupancy people indoor. We found out by analysis that year effective dose is lower than effective dose estimated by ICRP recommendation from the integral measurement that included only average radon concentration. Our analysis of estimation effective doses using measurement of several physical parameters was made only in one case and for the better specification is important to measure in different real occupancy houses. (authors)

Total-dose radiation effects data for semiconductor devices. 1985 supplement. Volume 2, part A

International Nuclear Information System (INIS)

Martin, K.E.; Gauthier, M.K.; Coss, J.R.; Dantas, A.R.V.; Price, W.E.

1986-05-01

Steady-state, total-dose radiation test data, are provided in graphic format for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. This volume provides data on integrated circuits. The data are presented in graphic, tabular, and/or narrative format, depending on the complexity of the integrated circuit. Most tests were done using the JPL or Boeing electron accelerator (Dynamitron) which provides a steady-state 2.5 MeV electron beam. However, some radiation exposures were made with a cobalt-60 gamma ray source, the results of which should be regarded as only an approximate measure of the radiation damage that would be incurred by an equivalent electron dose

A model for dose estimation in therapy of liver with intraarterial microspheres

International Nuclear Information System (INIS)

Zavgorodni, S.F.

1996-01-01

Therapy with intraarterial microspheres is a technique which involves incorporation of radioisotope-labelled microspheres into a capillary bed of tumour and normal tissue. Beta-emitters such as 90 Y and 166 Ho are used for this purpose. This technique provides tumour to normal tissue (TNT) dose ratios in the range of 2-10 and demonstrates significant clinical benefit, which could potentially be increased with more accurate dose predictions and delivery. However, dose calculations in this modality face the difficulties associated with nonuniform and inhomogeneous activity distribution. Most of the dose calculations used clinically do not account for the nonuniformity and assume uniform activity distribution. This paper is devoted to the development of a model which would allow more accurate prediction of dose distributions from microspheres. The model calculates dose assuming that microspheres are aggregated into randomly distributed clusters, and using precomputed dose kernels for the clusters. The dose kernel due to a microsphere cluster was found by numerical integration of a point source dose kernel over the volume of the cluster. It is shown that a random distribution of clusters produces an intercluster distance distribution which agrees well with the one measured by Pillai et al in liver. Dose volume histograms (DVHs) predicted by the model agree closely with the results of Roberson et al for normal tissue and tumour. Dose distributions for different concentrations and types of radioisotope, as well as for tumours of different radii, have been calculated to demonstrate the model's possible applications. (author)

Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

International Nuclear Information System (INIS)

Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G.

2002-01-01

The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7±17.1 and 40.4±16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7±4.8 ccm for 3D-HOF and 10.7±12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma

Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

Energy Technology Data Exchange (ETDEWEB)

Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G. [National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary)

2002-04-01

The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7{+-}17.1 and 40.4{+-}16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7{+-}4.8 ccm for 3D-HOF and 10.7{+-}12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma.

Ultraviolet radiation therapy and UVR dose models

Energy Technology Data Exchange (ETDEWEB)

Grimes, David Robert, E-mail: davidrobert.grimes@oncology.ox.ac.uk [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9, Ireland and Cancer Research UK/MRC Oxford Institute for Radiation Oncology, Gray Laboratory, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom)

2015-01-15

Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed.

Ultraviolet radiation therapy and UVR dose models

International Nuclear Information System (INIS)

Grimes, David Robert

2015-01-01

Ultraviolet radiation (UVR) has been an effective treatment for a number of chronic skin disorders, and its ability to alleviate these conditions has been well documented. Although nonionizing, exposure to ultraviolet (UV) radiation is still damaging to deoxyribonucleic acid integrity, and has a number of unpleasant side effects ranging from erythema (sunburn) to carcinogenesis. As the conditions treated with this therapy tend to be chronic, exposures are repeated and can be high, increasing the lifetime probability of an adverse event or mutagenic effect. Despite the potential detrimental effects, quantitative ultraviolet dosimetry for phototherapy is an underdeveloped area and better dosimetry would allow clinicians to maximize biological effect whilst minimizing the repercussions of overexposure. This review gives a history and insight into the current state of UVR phototherapy, including an overview of biological effects of UVR, a discussion of UVR production, illness treated by this modality, cabin design and the clinical implementation of phototherapy, as well as clinical dose estimation techniques. Several dose models for ultraviolet phototherapy are also examined, and the need for an accurate computational dose estimation method in ultraviolet phototherapy is discussed

Thermoluminescent accident dose reader with photodiode; Termoluminiscencni litalnik akcidentnih doz s fotodiodo

Energy Technology Data Exchange (ETDEWEB)

Miklavzic, U; Mihelic, M [Institut Jozef Stefan, Ljubljana (Yugoslavia)

1982-07-01

The field version of TL reader for accident dose region 0.01-20 Gy is described. For light detection, the thermostated photodiode was used permitting measurements at the ambient temperatures from -20 C degrees to 50 C degrees, and a new mode of the glow curve integration. Results can be presented as integral or peak values of the glow curve. The reader was adapted for dosemeters IJS-TLD08 from sintered CaF2:Mn pellets. (author)

SU-G-BRC-15: The Potential Clinical Significance of Dose Mapping Error for Intra- Fraction Dose Mapping for Lung Cancer Patients

Energy Technology Data Exchange (ETDEWEB)

Sayah, N [Thomas Cancer Center, Richmond, VA (United States); Weiss, E [Virginia Commonwealth University, Richmond, Virginia (United States); Watkins, W [University of Virginia, Charlottesville, VA (United States); Siebers, J [University of Virginia Health System, Charlottesville, VA (United States)

2016-06-15

Purpose: To evaluate the dose-mapping error (DME) inherent to conventional dose-mapping algorithms as a function of dose-matrix resolution. Methods: As DME has been reported to be greatest where dose-gradients overlap tissue-density gradients, non-clinical 66 Gy IMRT plans were generated for 11 lung patients with the target edge defined as the maximum 3D density gradient on the 0% (end of inhale) breathing phase. Post-optimization, Beams were copied to 9 breathing phases. Monte Carlo dose computed (with 2*2*2 mm{sup 3} resolution) on all 10 breathing phases was deformably mapped to phase 0% using the Monte Carlo energy-transfer method with congruent mass-mapping (EMCM); an externally implemented tri-linear interpolation method with voxel sub-division; Pinnacle’s internal (tri-linear) method; and a post-processing energy-mass voxel-warping method (dTransform). All methods used the same base displacement-vector-field (or it’s pseudo-inverse as appropriate) for the dose mapping. Mapping was also performed at 4*4*4 mm{sup 3} by merging adjacent dose voxels. Results: Using EMCM as the reference standard, no clinically significant (>1 Gy) DMEs were found for the mean lung dose (MLD), lung V20Gy, or esophagus dose-volume indices, although MLD and V20Gy were statistically different (2*2*2 mm{sup 3}). Pinnacle-to-EMCM target D98% DMEs of 4.4 and 1.2 Gy were observed ( 2*2*2 mm{sup 3}). However dTransform, which like EMCM conserves integral dose, had DME >1 Gy for one case. The root mean square RMS of the DME for the tri-linear-to- EMCM methods was lower for the smaller voxel volume for the tumor 4D-D98%, lung V20Gy, and cord D1%. Conclusion: When tissue gradients overlap with dose gradients, organs-at-risk DME was statistically significant but not clinically significant. Target-D98%-DME was deemed clinically significant for 2/11 patients (2*2*2 mm{sup 3}). Since tri-linear RMS-DME between EMCM and tri-linear was reduced at 2*2*2 mm{sup 3}, use of this resolution is

Organ or tissue doses, effective dose and collective effective dose from X-ray diagnosis, in Japan

International Nuclear Information System (INIS)

Murayama, Takashi; Nishizawa, Kanae; Noda, Yutaka; Kumamoto, Yoshikazu; Iwai, Kazuo.

1996-01-01

Effective doses and collective effective doses from X-ray diagnostic examinations were calculated on the basis of the frequency of examinations estimated by a nationwide survey and the organ or tissue doses experimentally determined. The average organ or tissue doses were determined with thermoluminescence dosimeters put at various sites of organs or tissues in an adult and a child phantom. Effective doses (effective dose equivalents) were calculated as the sum of the weighted equivalent doses in all the organs or tissues of the body. As the examples of results, the effective doses per radiographic examination were approximately 7 mGy for male, and 9 mGy for female angiocardiography, and about 3 mGy for barium meal. Annual collective effective dose from X-ray diagnostic examinations in 1986 were about 104 x 10 3 person Sv from radiography and 118 x 10 3 person Sv from fluoroscopy, with the total of 222 x 10 3 person Sv. (author)

Strategies to reduce radiation dose in cardiac PET/CT

Energy Technology Data Exchange (ETDEWEB)

Wu, Tung Hsin; Wu, Nien-Yun [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wang, Shyh-Jen [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wu, Jay [Institute of Radiological science, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, No.91 Hsueh-Shih Road, Taichung 40402, Taiwan (China)

2011-08-21

Background: Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications. Materials: Image quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan. Results: Radiation dose in RGH technique was 22.2{+-}4.0 mSv. It was reduced to 10.95{+-}0.82 and 4.13{+-}0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53{+-}0.5 to 0.16{+-}0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols. Conclusion: The proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

Population doses from terrestrial gamma exposure in China

International Nuclear Information System (INIS)

Ren, T.; Wang, Z.; Zhu, C.

1993-01-01

In order to estimate terrestrial gamma radiation exposures, three nationwide surveys have been completed since 1981. The population weighted outdoor and indoor arithmetic means of gamma dose rates based on momentary measurements using a NaI(T1) environmental radiation meter and a high pressured ionization chamber are 80.3 and 120 nGy.h -1 . The means based on integrating measurements using TLD natural radionuclides concentrations in soil, determined by gamma spectrometry analyses, are 72.8 and 102 nGy.h -1 , respectively. These surveys were conducted independently and equally representative. The best estimation of site-averaged and population weighted gamma dose rates in China, based on all these surveys, would be 70 and 98 nGy.h -1 for indoor and outdoor, respectively. The annual average of effective dose equivalent is 0.56 mSv. These values are higher than the world averages estimated by UNSCEAR. The main reason is that the concentrations of 232 Th and 40 K in soil of China are much higher than the world average estimated. (author). 4 refs, 2 tabs

Object-oriented process dose modeling for glovebox operations

International Nuclear Information System (INIS)

Boerigter, S.T.; Fasel, J.H.; Kornreich, D.E.

1999-01-01

The Plutonium Facility at Los Alamos National Laboratory supports several defense and nondefense-related missions for the country by performing fabrication, surveillance, and research and development for materials and components that contain plutonium. Most operations occur in rooms with one or more arrays of gloveboxes connected to each other via trolley gloveboxes. Minimizing the effective dose equivalent (EDE) is a growing concern as a result of steadily declining allowable dose limits being imposed and a growing general awareness of safety in the workplace. In general, the authors discriminate three components of a worker's total EDE: the primary EDE, the secondary EDE, and background EDE. A particular background source of interest is the nuclear materials vault. The distinction between sources inside and outside of a particular room is arbitrary with the underlying assumption that building walls and floors provide significant shielding to justify including sources in other rooms in the background category. Los Alamos has developed the Process Modeling System (ProMoS) primarily for performing process analyses of nuclear operations. ProMoS is an object-oriented, discrete-event simulation package that has been used to analyze operations at Los Alamos and proposed facilities such as the new fabrication facilities for the Complex-21 effort. In the past, crude estimates of the process dose (the EDE received when a particular process occurred), room dose (the EDE received when a particular process occurred in a given room), and facility dose (the EDE received when a particular process occurred in the facility) were used to obtain an integrated EDE for a given process. Modifications to the ProMoS package were made to utilize secondary dose information to use dose modeling to enhance the process modeling efforts

Affordable CZT SPECT with dose-time minimization (Conference Presentation)

Science.gov (United States)

Hugg, James W.; Harris, Brian W.; Radley, Ian

2017-03-01

PURPOSE Pixelated CdZnTe (CZT) detector arrays are used in molecular imaging applications that can enable precision medicine, including small-animal SPECT, cardiac SPECT, molecular breast imaging (MBI), and general purpose SPECT. The interplay of gamma camera, collimator, gantry motion, and image reconstruction determines image quality and dose-time-FOV tradeoffs. Both dose and exam time can be minimized without compromising diagnostic content. METHODS Integration of pixelated CZT detectors with advanced ASICs and readout electronics improves system performance. Because historically CZT was expensive, the first clinical applications were limited to small FOV. Radiation doses were initially high and exam times long. Advances have significantly improved efficiency of CZT-based molecular imaging systems and the cost has steadily declined. We have built a general purpose SPECT system using our 40 cm x 53 cm CZT gamma camera with 2 mm pixel pitch and characterized system performance. RESULTS Compared to NaI scintillator gamma cameras: intrinsic spatial resolution improved from 3.8 mm to 2.0 mm; energy resolution improved from 9.8% to reconstruction, result in minimized dose and exam time. With CZT cost improving, affordable whole-body CZT general purpose SPECT is expected to enable precision medicine applications.

Shutdown dose rate contribution from diagnostics in ITER upper port 18

Energy Technology Data Exchange (ETDEWEB)

Cheon, M.S., E-mail: munseong@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Pak, S.; An, Y.H.; Seon, C.R.; Lee, H.G. [National Fusion Research Institute, Daejeon (Korea, Republic of); Bertalot, L.; Krasilnikov, V. [ITER Organization, St Paul-lez-Durance (France); Zvonkov, A. [Agency ITER-RF, Moscow (Russian Federation)

2016-11-01

Highlights: • The Shutdown Dose Rate in the interspace of ITER upper port 18 was evaluated. • VUV spectrometer is the dominant contributor to the average SDR. • The existence and size of the blanket cooling pipes impacts significantly on SDR. - Abstract: D-T operation of ITER plasma will produce high-energy fusion neutrons those can activate materials around the place where human-access is necessary. The interspace of the diagnostic port is one of the area where human-access is necessary for the maintenance of diagnostic systems installed at the port, so it is important to evaluate a dose rate of the interspace area in order to comply with ALARA principle. The shutdown dose rate (SDR) in the interspace of ITER upper port 18 was evaluated by the Direct 1-Step (D1S) method using MCNP5 code. This port contains three diagnostics: Vacuum Ultra-Violet (VUV) Spectrometer, Neutron Activation System (NAS), and Upper Vertical Neutron Camera (UVNC). The contribution of each diagnostic in the port was evaluated by running separate upper port MCNP models those contain individual diagnostic only, and the total dose rate contribution was evaluated with the model which was fully integrated with all the diagnostics. The effect of the opening around the upper port plug and of the other ports was also investigated. The purpose of this assessment is to provide the shielding design basis for the preliminary design of the diagnostic integration in the port. The method and result of the calculation will be presented in this paper.

Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

International Nuclear Information System (INIS)

Vargas, J.; Vivanco, M.; Castro, E.

2014-08-01

In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

Assessment of tritium dose around Rajasthan Atomic Power Station (1989-1997)

International Nuclear Information System (INIS)

Verma, P.C.; Vijaykumar, B.; George, Thomas; Sankhla, Rajesh; Roy, Alpana; Vyas, P.V.; Gurg, R.P.

1999-01-01

Tritium monitoring in the atmospheric and aquatic environment forms an integral part of the environmental radiological measurements conducted around PHWR type Nuclear Power Plant sites as tritium is one of the predominantly produced radionuclides in such systems. This paper presents the tritium concentration levels in the atmospheric and aquatic environs of Rajasthan Atomic Power Station (RAPS) during 1989-1997. The committed effective doses due to tritium are computed on annual basis for different radial zones around RAPS. It is observed that the maximum dose due to tritium at 1.6 km post fence has been less than 1% of the dose limit (1 mSv) set by regulatory body for the members of the public and beyond 5 km distance it is only 0.4% of the limit. (author)

Dose optimization in CT examination of children

International Nuclear Information System (INIS)

Hojreh, A.; Prosch, H.

2012-01-01

Problems arise due to the increased clinical use of computed tomography (CT) and the high radiosensitivity of children. The ALARA concept (as low as reasonably achievable) prevails in pediatric radiology. Justified indications and full utilization of available dose optimization methods. Medical physicists and the manufacturers should support pediatric radiology in the implementation of the ALARA concept. The referring physicians and radiology staff should be integrated into training programs. Sufficient diagnostic image quality is paramount and not the pretty images. (orig.) [de

Radiation effects on and dose enhancement of electronic materials

International Nuclear Information System (INIS)

Srour, J.R.; Long, D.M.

1984-01-01

This book describes radiation effects on and dose enhancement factors for electronic materials. Alteration of the electrical properties of solid-state devices and integrated circuits by impinging radiation is well-known. Such changes may cause an electronic subsystem to fail, thus there is currently great interest in devising methods for avoiding radiation-induced degradation. The development of radiation-hardened devices and circuits is an exciting approach to solving this problem for many applications, since it could minimize the need for shielding or other system hardening techniques. Part 1 describes the basic mechanisms of radiation effects on electronic materials, devices, and integrated circuits. Radiation effects in bulk silicon and in silicon devices are treated. Ionizing radiation effects in silicon dioxide films and silicon MOS devices are discussed. Single event phenomena are considered. Key literature references and a bibliography are provided. Part II provides tabulations of dose enhancement factors for electronic devices in x-ray and gamma-ray environments. The data are applicable to a wide range of semiconductor devices and selected types of capacitors. Radiation environments discussed find application in system design and in radiation test facilities

Exposure to Low-Dose X-Ray Radiation Alters Bone Progenitor Cells and Bone Microarchitecture.

Science.gov (United States)

Lima, Florence; Swift, Joshua M; Greene, Elisabeth S; Allen, Matthew R; Cunningham, David A; Braby, Leslie A; Bloomfield, Susan A

2017-10-01

Exposure to high-dose ionizing radiation during medical treatment exerts well-documented deleterious effects on bone health, reducing bone density and contributing to bone growth retardation in young patients and spontaneous fracture in postmenopausal women. However, the majority of human radiation exposures occur in a much lower dose range than that used in the radiation oncology clinic. Furthermore, very few studies have examined the effects of low-dose ionizing radiation on bone integrity and results have been inconsistent. In this study, mice were irradiated with a total-body dose of 0.17, 0.5 or 1 Gy to quantify the early (day 3 postirradiation) and delayed (day 21 postirradiation) effects of radiation on bone microarchitecture and bone marrow stromal cells (BMSCs). Female BALBc mice (4 months old) were divided into four groups: irradiated (0.17, 0.5 and 1 Gy) and sham-irradiated controls (0 Gy). Micro-computed tomography analysis of distal femur trabecular bone from animals at day 21 after exposure to 1 Gy of X-ray radiation revealed a 21% smaller bone volume (BV/TV), 22% decrease in trabecular numbers (Tb.N) and 9% greater trabecular separation (Tb.Sp) compared to sham-irradiated controls (P X-rays, whereas osteoclastogenesis was enhanced. A better understanding of the effects of radiation on osteoprogenitor cell populations could lead to more effective therapeutic interventions that protect bone integrity for individuals exposed to low-dose ionizing radiation.

The Northern Marshall Islands radiological survey: Data and dose assessments

International Nuclear Information System (INIS)

Robison, W.L.; Noshkin, V.E.; Conrado, C.L.

1997-01-01

Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for 137 Cs, 90 Sr, 239+240 Pu and 241 Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from 137 Cs accounts for about 10% to 30% of the dose. 239+240 Pu and 241 Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y -1 . The background dose in the Marshall Islands is estimated to be 2.4 mSv y -1 to 4.5 mSv y -1 . The 50-y integral dose ranges from 0.5 to 65 mSv. 35 refs., 2 figs., 9 tabs

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

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

Mid-ventilation position planning: Optimal model for dose distribution in lung tumour

International Nuclear Information System (INIS)

Benchalal, M.; Leseur, J.; Chajon, E.; Cazoulat, G.; Haigron, P.; Simon, A.; Bellec, J.; Lena, H.; Crevoisier, R. de

2012-01-01

Purpose. - The dose distribution for lung tumour is estimated using a 3D-CT scan, and since a person breathes while the images are captured, the dose distribution doesn't reflect the reality. A 4D-CT scan integrates the motion of the tumour during breathing and, therefore, provides us with important information regarding tumour's motion in all directions, the motion volume (ITV) and the time-weighted average position (MVP). Patient and methods. - Based on these two concepts, we have estimated, for a lung carcinoma case a 3D dose distribution from a 3D-CT scan, and a 4D dose distribution from a 4-D CT scan. To this, we have applied a non-rigid registration to estimate the cumulative dose. Results. - Our study shows that the 4D dose estimation of the GTV is almost the same when made using MVP and ITV concepts, but sparring of the healthy lung is better done using the MPV model (MVP), as compared to the ITV model. This improvement of the therapeutic index allows, from a projection on the theoretical maximal dose to PTV (strictly restricted to doses for the lungs and the spinal cord), for an increase of about 11% on the total dose (maximal dose of 86 Gy for the ITV and 96 Gy for the MVP). Conclusion. - Further studies with more patients are needed to confirm our data. (authors)

Dose gradient curve: A new tool for evaluating dose gradient.

Science.gov (United States)

Sung, KiHoon; Choi, Young Eun

2018-01-01

Stereotactic radiotherapy, which delivers an ablative high radiation dose to a target volume for maximum local tumor control, requires a rapid dose fall-off outside the target volume to prevent extensive damage to nearby normal tissue. Currently, there is no tool to comprehensively evaluate the dose gradient near the target volume. We propose the dose gradient curve (DGC) as a new tool to evaluate the quality of a treatment plan with respect to the dose fall-off characteristics. The average distance between two isodose surfaces was represented by the dose gradient index (DGI) estimated by a simple equation using the volume and surface area of isodose levels. The surface area was calculated by mesh generation and surface triangulation. The DGC was defined as a plot of the DGI of each dose interval as a function of the dose. Two types of DGCs, differential and cumulative, were generated. The performance of the DGC was evaluated using stereotactic radiosurgery plans for virtual targets. Over the range of dose distributions, the dose gradient of each dose interval was well-characterized by the DGC in an easily understandable graph format. Significant changes in the DGC were observed reflecting the differences in planning situations and various prescription doses. The DGC is a rational method for visualizing the dose gradient as the average distance between two isodose surfaces; the shorter the distance, the steeper the dose gradient. By combining the DGC with the dose-volume histogram (DVH) in a single plot, the DGC can be utilized to evaluate not only the dose gradient but also the target coverage in routine clinical practice.

Dose loading mathematical modelling of moving through heterogeneous radiation fields

International Nuclear Information System (INIS)

Batyij, Je.V.; Kotlyarov, V.T.

2006-01-01

Software component for management of data on gamma exposition dose spatial distribution was created in the frameworks of the Ukryttya information model creation. Availability of state-of-the-art programming technologies (NET., ObjectARX) for integration of different models of radiation-hazardous condition to digital engineer documentation system (AutoCAD) was shown on the basis of the component example

Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation

International Nuclear Information System (INIS)

Vaiman, M.; Guenet, J.-L.; Maas, J.; Nizza, P.

1966-05-01

Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of γ radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [fr

HIGH-DOSE RATE BRACHYTHERAPY IN CARCINOMA CERVIX STAGE IIIB

Directory of Open Access Journals (Sweden)

Sathya Maruthavanan

2016-07-01

Full Text Available INTRODUCTION Radiotherapy is the standard treatment in locally advanced (IIB-IVA and early inoperable cases. The current standard of practice with curable intent is concurrent chemoradiation in which intracavitary brachytherapy is an integral component of radiotherapy. This study aims at assessing the efficacy of HDR ICBT (High-dose rate intracavitary brachytherapy in terms local response, normal tissue reactions, and feasibility. METHODS AND MATERIALS A total of 20 patients of stage IIIB cancer of the uterine cervix were enrolled in the study and were planned to receive concurrent chemotherapy weekly along with EBRT (external beam radiotherapy to a dose of 50 Gy/25 Fr. Suitability for ICBT was assessed at 40 Gy/20 Fr. 6/20 patients were suitable at 40 Gy and received HDR ICBT with a dose of 5.5 Gy to point A in 4 sessions (5.5 Gy/4 Fr. The remaining 14/20 patients completed 50 Gy and received HDR ICBT with a dose of 6 Gy to point A in 3 sessions (6 Gy/3 Fr. RESULTS A total of 66 intracavitary applications were done and only one application required dose modification due to high bladder dose, the pelvic control rate was 85% (17/20. 10% (2/20 had stable disease and 5% (1/20 had progressive disease at one year of follow up. When toxicity was considered only 15% developed grade I and grade II rectal complications. Patient compliance and acceptability was 100%. Patients were very comfortable with the short treatment time as compared with patients on LDR ICBT (low-dose rate intracavitary brachytherapy treatment interviewed during the same period. CONCLUSION This study proves that HDR brachytherapy is efficacious and feasible in carcinoma of cervix stage IIIB. It also proves that good dose distribution can be achieved with HDR intracavitary facility by the use of dose optimization. The short treatment time in HDR ICBT makes it possible to maintain this optimised dose distribution throughout the treatment providing a gain in the therapeutic ratio and

The researches on the effects of low doses irradiation

International Nuclear Information System (INIS)

2009-02-01

All research conducted as part of 'Risc-Rad' and those conducted by actors in international programs on low doses allow progress in understanding mechanisms of carcinogenesis associated with irradiation. The data do not question the use in radiation protection, risk estimation models based on a linear increase of the risk with the dose of radiation. Nevertheless, they show that the nature of biological responses induced by low doses of radiation has differences with the responses induced by high doses of radiation. They also show the diversity of effects/dose relationships as the mechanism observed and the importance of genetic predisposition in the individual sensitivity to low doses of radiation. It is therefore essential to continue to bring new data to better understand the complex biological effects and their impact on the establishment of radiation protection standards. In addition, the results have often been at the cellular level. The diversity of responses induced by radiations is also a function of cell types observed, the aging of cells and tissue organization. It is essential to strengthen researches at the tissue and body level, involving in vitro and in vivo approaches while testing the hypothesis in epidemiology with a global approach to systems biology. Over the past four years, the collaboration between partners of 'Risc-Rad' using experimental biology approaches and those using mathematical modeling techniques aimed at developing a new model describing the carcinogenesis induced by low radiation doses. On an other hand, The High level expert group on European low dose risk research (H.L.E.G.) develop programmes in the area of low dose irradiation (Germany, Finland, France, Italy and United Kingdom). It proposed a structure of trans national government called M.E.L.O.D.I. ( multidisciplinary european low dose initiative). Its objective is to structure and integrate European research by gathering around a common programme of multidisciplinary

Implementation of a revised numerical integration technique into QAD

International Nuclear Information System (INIS)

De Gangi, N.L.

1983-01-01

A technique for numerical integration through a uniform volume source is developed. It is applied to gamma radiation transport shielding problems. The method is based on performing a numerical angular and ray point kernel integration and is incorporated into the QAD-CG computer code (i.e. QAD-UE). Several test problems are analyzed with this technique. Convergence properties of the method are analyzed. Gamma dose rates from a large tank and post LOCA dose rates inside a containment building are evaluated. Results are consistent with data from other methods. The new technique provides several advantages. User setup requirements for large volume source problems are reduced from standard point kernel requirements. Calculational efficiencies are improved. An order of magnitude improvement is seen with a test problem

Doses to early entrants to the A-bombed areas and to residents of the fallout areas and 137Cs in soil of the 'black rain' area in Hiroshima

International Nuclear Information System (INIS)

Takeshita, Kenji

1976-01-01

An external exposure dose from residual activity (induced radioactivity in the fallout areas and radioactive fallout in the ''black rain'' area) caused by an atomic bomb in Hiroshima was estimated. The integrated doses to the infinite time averaged 101 rads in the atomic bombed area of Hiroshima and 32 rads in that area of Nagasaki. According to the measurement by investigators, the integrated doses of the external exposure dose due to radioactive fallout averaged 13 rads. The amount of 137 Cs in soils was determined in the southest slanting surface

Optimized dose distribution of a high dose rate vaginal cylinder

International Nuclear Information System (INIS)

Li Zuofeng; Liu, Chihray; Palta, Jatinder R.

1998-01-01

Purpose: To present a comparison of optimized dose distributions for a set of high-dose-rate (HDR) vaginal cylinders calculated by a commercial treatment-planning system with benchmark calculations using Monte-Carlo-calculated dosimetry data. Methods and Materials: Optimized dose distributions using both an isotropic and an anisotropic dose calculation model were obtained for a set of HDR vaginal cylinders. Mathematical optimization techniques available in the computer treatment-planning system were used to calculate dwell times and positions. These dose distributions were compared with benchmark calculations with TG43 formalism and using Monte-Carlo-calculated data. The same dwell times and positions were used for a quantitative comparison of dose calculated with three dose models. Results: The isotropic dose calculation model can result in discrepancies as high as 50%. The anisotropic dose calculation model compared better with benchmark calculations. The differences were more significant at the apex of the vaginal cylinder, which is typically used as the prescription point. Conclusion: Dose calculation models available in a computer treatment-planning system must be evaluated carefully to ensure their correct application. It should also be noted that when optimized dose distribution at a distance from the cylinder surface is calculated using an accurate dose calculation model, the vaginal mucosa dose becomes significantly higher, and therefore should be carefully monitored

The NIOSH Radiation Dose Reconstruction Project: managing technical challenges.

Science.gov (United States)

Moeller, Matthew P; Townsend, Ronald D; Dooley, David A

2008-07-01

Approximately two years after promulgation of the Energy Employees Occupational Illness Compensation Program Act, the National Institute for Occupational Safety and Health Office of Compensation and Analysis Support selected a contractor team to perform many aspects of the radiation dose reconstruction process. The project scope and schedule necessitated the development of an organization involving a comparatively large number of health physicists. From the initial stages, there were many technical and managerial challenges that required continuous planning, integration, and conflict resolution. This paper identifies those challenges and describes the resolutions and lessons learned. These insights are hopefully useful to managers of similar scientific projects, especially those requiring significant data, technical methods, and calculations. The most complex challenge has been to complete defensible, individualized dose reconstructions that support timely compensation decisions at an acceptable production level. Adherence to applying claimant-favorable and transparent science consistent with the requirements of the Act has been the key to establishing credibility, which is essential to this large and complex project involving tens of thousands of individual stakeholders. The initial challenges included garnering sufficient and capable scientific staff, developing an effective infrastructure, establishing necessary methods and procedures, and integrating activities to ensure consistent, quality products. The continuing challenges include maintaining the project focus on recommending a compensation determination (rather than generating an accurate dose reconstruction), managing the associated very large data and information management challenges, and ensuring quality control and assurance in the presence of an evolving infrastructure. The lessons learned concern project credibility, claimant favorability, project priorities, quality and consistency, and critical

Dynamically accumulated dose and 4D accumulated dose for moving tumors

International Nuclear Information System (INIS)

Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald

2012-01-01

Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a “pulsed beam”; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a “continuous beam.” A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose

PABLM, Doses from Radioactive Releases to Atmosphere and Food Chain

International Nuclear Information System (INIS)

Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.

1983-01-01

1 - Description of problem or function: PABLM calculates internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides after the releases have ended. Radioactive decay is considered during the release, after deposition, and during holdup of food after harvest. The radiation dose models consider exposure to radionuclides deposited on the ground or crops from contaminated air or irrigation water, radionuclides in contaminated drinking water, aquatic foods raised in contaminated water, and radionuclides in bodies of water and sediments where people might fish, boat, or swim. For vegetation, the radiation dose model considers both direct deposition and uptake through roots. Doses may be calculated for either a maximum-exposed individual or for a population group. The program is designed to calculate accumulated radiation doses from the chronic ingestion of food products that contain radionuclides and doses from the external exposure to radionuclides in the environment. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. 2 - Method of solution: A chain decay scheme including branching for transitions to and from isomeric states is used for radioactive decay. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radio- logical Protection (ICRP) for body burdens and the maximum possible concentration (MPC) for each radionuclide. These doses are calculated as a function of radionuclide concentration in food products, ingestion rates, and a radionuclide-specific dose- commitment factor. Radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption

Dose-volume and biological-model based comparison between helical tomotherapy and (inverse-planned) IMAT for prostate tumours

International Nuclear Information System (INIS)

Iori, Mauro; Cattaneo, Giovanni Mauro; Cagni, Elisabetta; Fiorino, Claudio; Borasi, Gianni; Riccardo, Calandrino; Iotti, Cinzia; Fazio, Ferruccio; Nahum, Alan E.

2008-01-01

Background and purpose: Helical tomotherapy (HT) and intensity-modulated arc therapy (IMAT) are two arc-based approaches to the delivery of intensity-modulated radiotherapy (IMRT). Through plan comparisons we have investigated the potential of IMAT, both with constant (conventional or IMAT-C) and variable (non-conventional or IMAT-NC, a theoretical exercise) dose-rate, to serve as an alternative to helical tomotherapy. Materials and methods: Six patients with prostate tumours treated by HT with a moderately hypo-fractionated protocol, involving a simultaneous integrated boost, were re-planned as IMAT treatments. A method for IMAT inverse-planning using a commercial module for static IMRT combined with a multi-leaf collimator (MLC) arc-sequencing was developed. IMAT plans were compared to HT plans in terms of dose statistics and radiobiological indices. Results: Concerning the planning target volume (PTV), the mean doses for all PTVs were similar for HT and IMAT-C plans with minimum dose, target coverage, equivalent uniform dose (EUD) and tumour control probability (TCP) values being generally higher for HT; maximum dose and degree of heterogeneity were instead higher for IMAT-C. In relation to organs at risk, mean doses and normal tissue complication probability (NTCP) values were similar between the two modalities, except for the penile bulb where IMAT was significantly better. Re-normalizing all plans to the same rectal toxicity (NTCP = 5%), the HT modality yielded higher TCP than IMAT-C but there was no significant difference between HT and IMAT-NC. The integral dose with HT was higher than that for IMAT. Conclusions: with regards to the plan analysis, the HT is superior to IMAT-C in terms of target coverage and dose homogeneity within the PTV. Introducing dose-rate variation during arc-rotation, not deliverable with current linac technology, the simulations result in comparable plan indices between (IMAT-NC) and HT

Technical Note: SCUDA: A software platform for cumulative dose assessment

Energy Technology Data Exchange (ETDEWEB)

Park, Seyoun; McNutt, Todd; Quon, Harry; Wong, John; Lee, Junghoon, E-mail: rshekhar@childrensnational.org, E-mail: junghoon@jhu.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 (United States); Plishker, William [IGI Technologies, Inc., College Park, Maryland 20742 (United States); Shekhar, Raj, E-mail: rshekhar@childrensnational.org, E-mail: junghoon@jhu.edu [IGI Technologies, Inc., College Park, Maryland 20742 and Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Health System, Washington, DC 20010 (United States)

2016-10-15

Purpose: Accurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (SCUDA) that can be seamlessly integrated into the clinical workflow. Methods: SCUDA consists of deformable image registration (DIR), segmentation, dose computation modules, and a graphical user interface. It is connected to our image PACS and radiotherapy informatics databases from which it automatically queries/retrieves patient images, radiotherapy plan, beam data, and daily treatment information, thus providing an efficient and unified workflow. For accurate registration of the planning CT and daily CBCTs, the authors iteratively correct CBCT intensities by matching local intensity histograms during the DIR process. Contours of the target tumor and critical structures are then propagated from the planning CT to daily CBCTs using the computed deformations. The actual delivered daily dose is computed using the registered CT and patient setup information by a superposition/convolution algorithm, and accumulated using the computed deformation fields. Both DIR and dose computation modules are accelerated by a graphics processing unit. Results: The cumulative dose computation process has been validated on 30 head and neck (HN) cancer cases, showing 3.5 ± 5.0 Gy (mean±STD) absolute mean dose differences between the planned and the actually delivered doses in the parotid glands. On average, DIR, dose computation, and segmentation take 20 s/fraction and 17 min for a 35-fraction treatment including additional computation for dose accumulation. Conclusions: The authors developed a unified software platform that provides

A review of radiology staff doses and dose monitoring requirements

International Nuclear Information System (INIS)

Martin, C. J.

2009-01-01

Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand. (authors)

Calculation of dose-rate conversion factors for external exposure to photons and electrons

International Nuclear Information System (INIS)

Kocher, D.C.

1978-01-01

Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air

Evaluation of occupational dose from the special procedures guided by fluoroscopy: cardiac catheterism

International Nuclear Information System (INIS)

Silva, Amanda Juliene da

2011-01-01

The purpose of this study was to evaluate the dose received by health professionals in the hemodynamic sector of a university hospital in Sao Paulo city. A self-applied questionnaire was used to delineate the profile of health professionals, taking into account sociodemographic variables and variables related to the work with ionizing radiation. The assessment of occupational doses was performed by consulting of the individual dose records of the institution database from 2000 to 2009. A total of 240 records was evaluated, corresponding to 38 active professionals (2009), divided in different professional category: physician, nurses, radiologic technologists and nursing assistants. The annual doses were compared with the limits established by national regulatory authorities. Based on the effective doses received and recorded during the studied period, experimental measures were performed with TL dosimeters in five physicians to evaluate the equivalent dose, in the left hand, during hemodynamic procedures. In addition, the radioprotection measures adopted by health professionals were verified. This study allowed delineating the profile of medical staff that integrates the hemodynamic service as well as knowing the distribution of their doses in relation to limits over the years. (author)

Gamma dose from activation of internal shields in IRIS reactor.

Science.gov (United States)

Agosteo, Stefano; Cammi, Antonio; Garlati, Luisella; Lombardi, Carlo; Padovani, Enrico

2005-01-01

The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressuriser and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield.

Gamma dose from activation of internal shields in IRIS reactor

International Nuclear Information System (INIS)

Agosteo, S.; Cammi, A.; Garlati, L.; Lombardi, C.; Padovani, E.

2005-01-01

The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressurizer and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60 Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield. (authors)

Parotid gland tumors: A comparison of postoperative radiotherapy techniques using three dimensional (3D) dose distributions and dose-volume histograms (DVHs)

International Nuclear Information System (INIS)

Yaparpalvi, Ravindra; Fontenla, Doracy P.; Tyerech, Sangeeta K.; Boselli, Lucia R.; Beitler, Jonathan J.

1998-01-01

Purpose: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Methods and Materials: The CT-scans of a representative parotid patient were used. The field size was 9 x 11 cm, the separation was 15.5 cm, and the prescription depth was 4.5 cm. Using 3D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and dose-volume histogram (DVH), nine treatment techniques were compared. [1] unilateral 6 MV photons [2] unilateral 12 MeV electrons [3] unilateral 16 MeV electrons [4] an ipsilateral wedge pair technique using 6 MV photons [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting) [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting) [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting) [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥ 30% of the prescribed dose was 100% for techniques [1], [8] and [9], and < 5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1], [8] and [9] contributed to ≥ 50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed electron-photon beams [8] and [9] are not recommended treatment techniques for unilateral parotid irradiation because of high doses delivered to the

''Low dose'' and/or ''high dose'' in radiation protection: A need to setting criteria for dose classification

International Nuclear Information System (INIS)

Sohrabi, M.

1997-01-01

The ''low dose'' and/or ''high dose'' of ionizing radiation are common terms widely used in radiation applications, radiation protection and radiobiology, and natural radiation environment. Reading the title, the papers of this interesting and highly important conference and the related literature, one can simply raise the question; ''What are the levels and/or criteria for defining a low dose or a high dose of ionizing radiation?''. This is due to the fact that the criteria for these terms and for dose levels between these two extreme quantities have not yet been set, so that the terms relatively lower doses or higher doses are usually applied. Therefore, setting criteria for classification of radiation doses in the above mentioned areas seems a vital need. The author while realizing the existing problems to achieve this important task, has made efforts in this paper to justify this need and has proposed some criteria, in particular for the classification of natural radiation areas, based on a system of dose limitation. (author)

Low-dose CT image reconstruction using gain intervention-based dictionary learning

Science.gov (United States)

Pathak, Yadunath; Arya, K. V.; Tiwari, Shailendra

2018-05-01

Computed tomography (CT) approach is extensively utilized in clinical diagnoses. However, X-ray residue in human body may introduce somatic damage such as cancer. Owing to radiation risk, research has focused on the radiation exposure distributed to patients through CT investigations. Therefore, low-dose CT has become a significant research area. Many researchers have proposed different low-dose CT reconstruction techniques. But, these techniques suffer from various issues such as over smoothing, artifacts, noise, etc. Therefore, in this paper, we have proposed a novel integrated low-dose CT reconstruction technique. The proposed technique utilizes global dictionary-based statistical iterative reconstruction (GDSIR) and adaptive dictionary-based statistical iterative reconstruction (ADSIR)-based reconstruction techniques. In case the dictionary (D) is predetermined, then GDSIR can be used and if D is adaptively defined then ADSIR is appropriate choice. The gain intervention-based filter is also used as a post-processing technique for removing the artifacts from low-dose CT reconstructed images. Experiments have been done by considering the proposed and other low-dose CT reconstruction techniques on well-known benchmark CT images. Extensive experiments have shown that the proposed technique outperforms the available approaches.

Quantification of dose uncertainties for the bladder in prostate cancer radiotherapy based on dominant eigenmodes

Science.gov (United States)

Rios, Richard; Acosta, Oscar; Lafond, Caroline; Espinosa, Jairo; de Crevoisier, Renaud

2017-11-01

In radiotherapy for prostate cancer the dose at the treatment planning for the bladder may be a bad surrogate of the actual delivered dose as the bladder presents the largest inter-fraction shape variations during treatment. This paper presents PCA models as a virtual tool to estimate dosimetric uncertainties for the bladder produced by motion and deformation between fractions. Our goal is to propose a methodology to determine the minimum number of modes required to quantify dose uncertainties of the bladder for motion/deformation models based on PCA. We trained individual PCA models using the bladder contours available from three patients with a planning computed tomography (CT) and on-treatment cone-beam CTs (CBCTs). Based on the above models and via deformable image registration (DIR), we estimated two accumulated doses: firstly, an accumulated dose obtained by integrating the planning dose over the Gaussian probability distribution of the PCA model; and secondly, an accumulated dose obtained by simulating treatment courses via a Monte Carlo approach. We also computed a reference accumulated dose for each patient using his available images via DIR. Finally, we compared the planning dose with the three accumulated doses, and we calculated local dose variability and dose-volume histogram uncertainties.

Incase of Same Region Treatment by using a Tomotherapy and a Linear Accelerator Absorbed Dose Evaluation of Normal Tissues and a Tumor

International Nuclear Information System (INIS)

Cheon, Geum Seong; Kim, Chang Uk; Kim, Hoi Nam; Heo, Gyeong Hun; Song, Jin Ho; Hong, Joo Yeong; Jeong, Jae Yong

2010-01-01

Treating same region with different modalities there is a limit to evaluate the total absorbed dose of normal tissues. The reason is that it does not support to communication each modalities yet. In this article, it evaluates absorbed dose of the patients who had been treated same region by a tomotherapy and a linear accelerator. After reconstructing anatomic structure with a anthropomorphic phantom, administrate 45 Gy to a tumor in linac plan system as well as prescribe 15 Gy in tomotherapy plan system for make an ideal treatment plan. After the plan which made by tomoplan system transfers to the oncentra plan system for reproduce plan under the same condition and realize total treatment plan with summation 45 Gy linac treatment plan. To evaluate the absorbed dose of two different modalities, do a comparative study both a simple summation dose values and integration dose values. Then compare and analyze absorbed dose of normal tissues and a tumor with the patients who had been exposured radiation by above two different modalities. The result of compared data, in case of minimum dose, there are big different dose values in spleen (12.4%). On the other hand, in case of the maximum dose, it reports big different in a small bowel (10.2%) and a cord (5.8%) in head and neck cancer patients, there presents that oral (20.3%), right lens (7.7%) in minimum dose value. About maximum dose, it represents that spinal (22.5), brain stem (12%), optic chiasm (8.9%), Rt lens (11.5%), mandible (8.1%), pituitary gland (6.2%). In case of Rt abdominal cancer patients, there represents big different minimum dose as Lt kidney (20.3%), stomach (8.1%) about pelvic cancer patients, it reports there are big different in minimum dose as a bladder (15.2%) as well as big different value in maximum dose as a small bowel (5.6%), a bladder (5.5%) in addition, making treatment plan it is able us to get. In case of comparing both simple summation absorbed dose and integration absorbed dose, the

A Semiempirical Approach to the Determination of Daily Erythemal Doses.

Science.gov (United States)

Silva, Abel A; Yamamoto, Ana L C; Corrêa, Marcelo P

2018-02-15

The maintenance of ground-based instruments to measure the incidence of ultraviolet radiation (UVR) from the Sun demands strict and well-developed procedures. A piece of equipment can be out of service for a couple of weeks or months for calibration, repair or even the improvement of the facilities where it has been set up. However, the replacement of an instrument in such circumstances can be logistically and financially prohibitive. On the other hand, the lack of data can jeopardize a long-term experiment. In this study, we introduce a semiempirical approach to the determination of the theoretical daily erythemal dose (DED t ) for periods of instrumental absence in a tropical site. The approach is based on 5 years of ground-based measurements of daily erythemal dose (DED) linearly correlated with parameters of total ozone column (TOC) and reflectivity (R PC ) from the Ozone Monitoring Instrument (OMI) and the cosine of solar zenith angle at noon (SZA n ). Seventeen months of missing ground-based data were replaced with DED t , leading to a complete 5-year series of data. The lowest and the highest values of typical DED were 2411 ± 322 J m -2 (1σ) (winter) and 5263 ± 997 J m -2 (summer). The monthly integrated erythemal dose (mED) varied from 59 kJ m -2 (winter) to 162 kJ m -2 (summer). Both of them depended mainly on cos(SZA n ) and R PC . The 12-month integrated erythemal dose (12-ED) ranged from 1350 kJ m -2 to 1546 kJ m -2 , but it can depend significantly on other atmospheric parameter (maybe aerosols) not explicitly considered here. © 2018 The American Society of Photobiology.

SUBDOSA: a computer program for calculating external doses from accidental atmospheric releases of radionuclides

International Nuclear Information System (INIS)

Strenge, D.L.; Watson, E.C.; Houston, J.R.

1975-06-01

A computer program, SUBDOSA, was developed for calculating external γ and β doses to individuals from the accidental release of radionuclides to the atmosphere. Characteristics of SUBDOSA are: doses from both γ and β radiation are calculated as a function of depth in tissue, summed and reported as skin, eye, gonadal, and total body dose; doses are calculated for releases within each of several release time intervals and nuclide inventories and atmospheric dispersion conditions are considered for each time interval; radioactive decay is considered during the release and/or transit using a chain decay scheme with branching to account for transitions to and from isomeric states; the dose from gamma radiation is calculated using a numerical integration technique to account for the finite size of the plume; and the program computes and lists the normalized air concentrations at ground level as a function of distance from the point of release. (auth)

Quantitative analysis of biological responses to low dose-rate γ-radiation, including dose, irradiation time, and dose-rate

International Nuclear Information System (INIS)

Magae, J.; Furukawa, C.; Kawakami, Y.; Hoshi, Y.; Ogata, H.

2003-01-01

Full text: Because biological responses to radiation are complex processes dependent on irradiation time as well as total dose, it is necessary to include dose, dose-rate and irradiation time simultaneously to predict the risk of low dose-rate irradiation. In this study, we analyzed quantitative relationship among dose, irradiation time and dose-rate, using chromosomal breakage and proliferation inhibition of human cells. For evaluation of chromosome breakage we assessed micronuclei induced by radiation. U2OS cells, a human osteosarcoma cell line, were exposed to gamma-ray in irradiation room bearing 50,000 Ci 60 Co. After the irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, cytoplasm and nucleus were stained with DAPI and propidium iodide, and the number of binuclear cells bearing micronuclei was determined by fluorescent microscopy. For proliferation inhibition, cells were cultured for 48 h after the irradiation and [3H] thymidine was pulsed for 4 h before harvesting. Dose-rate in the irradiation room was measured with photoluminescence dosimeter. While irradiation time less than 24 h did not affect dose-response curves for both biological responses, they were remarkably attenuated as exposure time increased to more than 7 days. These biological responses were dependent on dose-rate rather than dose when cells were irradiated for 30 days. Moreover, percentage of micronucleus-forming cells cultured continuously for more than 60 days at the constant dose-rate, was gradually decreased in spite of the total dose accumulation. These results suggest that biological responses at low dose-rate, are remarkably affected by exposure time, that they are dependent on dose-rate rather than total dose in the case of long-term irradiation, and that cells are getting resistant to radiation after the continuous irradiation for 2 months. It is necessary to include effect of irradiation time and dose-rate sufficiently to evaluate risk

Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

International Nuclear Information System (INIS)

Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

2015-01-01

Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

Calculation of the gamma-dose rate from a continuously emitted plume

International Nuclear Information System (INIS)

Huebschmann, W.; Papadopoulos, D.

1975-06-01

A computer model is presented which calculates the long term gamma dose rate caused by the radioactive off-gas continuously emitted from a stack. The statistical distribution of the wind direction and velocity and of the stability categories is taken into account. The emitted activity, distributed in the atmosphere according to this statistics, is assumed to be concentrated at the mesh points of a three-dimensional grid. The grid spacing and the integration limits determine the accuracy as well as the computer time needed. When calculating the dose rate in a given wind direction, the contribution of the activity emitted into the neighbouring sectors is evaluated. This influence is demonstrated in the results, which are calculated with a error below 3% and compared to the dose rate distribution curves of the submersion model and the model developed by K.J. Vogt. (orig.) [de

Effect of Hashimoto thyroiditis on low-dose radioactive-iodine remnant ablation.

Science.gov (United States)

Kwon, Hyungju; Choi, June Young; Moon, Jae Hoon; Park, Hyo Jin; Lee, Won Woo; Lee, Kyu Eun

2016-04-01

Radioactive-iodine remnant ablation is an integral part of the papillary thyroid carcinoma (PTC) treatment. Although a minimum dose is usually recommended, there is controversy as to whether the low-dose (1100 MBq) radioactive-iodine remnant ablation is adequate for selected patients. A retrospective cohort study was conducted on 691 patients. Patients with no remnant thyroid on the follow-up whole body scan and low stimulated thyroglobulin (sTg) level (Hashimoto thyroiditis based on histopathology diagnosis (odds ratio [OR] = 3.23; p Hashimoto thyroiditis and elevated sTg are negative predictive factors for successful low-dose radioactive-iodine remnant ablation treatment. An appropriate risk-adjusted approach may improve the efficacy of radioactive-iodine remnant ablation treatment. © 2015 Wiley Periodicals, Inc. Head Neck 38: E730-E735, 2016. © 2015 Wiley Periodicals, Inc.

WRAITH, Internal and External Doses from Atmospheric Release of Isotopes

International Nuclear Information System (INIS)

1984-01-01

1 - Description of problem or function: WRAITH calculates the atmospheric transport of radioactive material to each of a number of downwind receptor points and the external and internal doses to a reference man at each of the receptor points. 2 - Method of solution: The movement of the released material through the atmosphere is calculated using a bivariate straight-line Gaussian distribution model with Pasquill values for standard deviations. The quantity of material in the released cloud is modified during its transit time to account for radioactive decay and daughter production. External doses due to exposure to the cloud can be calculated using a semi-infinite cloud approximation or a 'finite plume' three-dimensional point-kernel numerical integration technique. Internal doses due to acute inhalation are calculated using the ICRP Task Group Model and a four-segmented gastro- intestinal tract model. Translocation of the material between body compartments and retention in the body compartments are calculated using multiple exponential retention functions. Internal doses to each organ are calculated as sums of cross-organ doses with each target organ irradiated by radioactive material in a number of source organs. All doses are calculated in rads with separate values determined for high-LET and low-LET radiation. 3 - Restrictions on the complexity of the problem: - Doses to only three target organs (total body, red bone marrow, and the lungs) are considered and acute inhalation is the only pathway for material to enter the body. The dose response model is not valid for high-LET radiation other than alphas. The high-LET calculation ignores the contributions of neutrons, spontaneous fission fragments, and alpha recoil nuclei

A photocurrent compensation method of bipolar transistors under high dose rate radiation and its experimental research

International Nuclear Information System (INIS)

Yin Xuesong; Liu Zhongli; Li Chunji; Yu Fang

2005-01-01

Experiment using discrete bipolar transistors has been performed to verify the effect of the photocurrent compensation method. The theory of the dose rate effects of bipolar transistors and the photocurrent compensation method are introduced. The comparison between the response of hardened and unhardened circuits under high dose rate radiation is discussed. The experimental results show instructiveness to the hardness of bipolar integrated circuits under transient radiation. (authors)

Feasibility of RACT for 3D dose measurement and range verification in a water phantom

Energy Technology Data Exchange (ETDEWEB)

Alsanea, Fahed [School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, Indiana 47907-2051 (United States); Moskvin, Vadim [Radiation Oncology, Indiana University School of Medicine, 535 Barnhill Drive, RT 041, Indianapolis, Indiana 46202-5289 (United States); Stantz, Keith M., E-mail: kstantz@purdue.edu [School of Health Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, Indiana 47907-2051 and Radiology and Imaging Sciences, Indiana University School of Medicine, 950 West Walnut Street, Indianapolis, Indiana 46202-5289 (United States)

2015-02-15

Purpose: The objective of this study is to establish the feasibility of using radiation-induced acoustics to measure the range and Bragg peak dose from a pulsed proton beam. Simulation studies implementing a prototype scanner design based on computed tomographic methods were performed to investigate the sensitivity to proton range and integral dose. Methods: Derived from thermodynamic wave equation, the pressure signals generated from the dose deposited from a pulsed proton beam with a 1 cm lateral beam width and a range of 16, 20, and 27 cm in water using Monte Carlo methods were simulated. The resulting dosimetric images were reconstructed implementing a 3D filtered backprojection algorithm and the pressure signals acquired from a 71-transducer array with a cylindrical geometry (30 × 40 cm) rotated over 2π about its central axis. Dependencies on the detector bandwidth and proton beam pulse width were performed, after which, different noise levels were added to the detector signals (using 1 μs pulse width and a 0.5 MHz cutoff frequency/hydrophone) to investigate the statistical and systematic errors in the proton range (at 20 cm) and Bragg peak dose (of 1 cGy). Results: The reconstructed radioacoustic computed tomographic image intensity was shown to be linearly correlated to the dose within the Bragg peak. And, based on noise dependent studies, a detector sensitivity of 38 mPa was necessary to determine the proton range to within 1.0 mm (full-width at half-maximum) (systematic error < 150 μm) for a 1 cGy Bragg peak dose, where the integral dose within the Bragg peak was measured to within 2%. For existing hydrophone detector sensitivities, a Bragg peak dose of 1.6 cGy is possible. Conclusions: This study demonstrates that computed tomographic scanner based on ionizing radiation-induced acoustics can be used to verify dose distribution and proton range with centi-Gray sensitivity. Realizing this technology into the clinic has the potential to significantly

A Paradigm Shift in Low Dose Radiation Biology

Directory of Open Access Journals (Sweden)

Z. Alatas

2015-08-01

Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

Estimating effective doses to children from CT examinations

International Nuclear Information System (INIS)

Heron, J.C.L.

2000-01-01

Full text: Assessing doses to patients in diagnostic radiology is an integral part of implementing optimisation of radiation protection. Sources of normalised data are available for estimating doses to adults undergoing CT examinations, but for children this is not the case. This paper describes a simple method for estimating effective doses arising from paediatric CT examinations. First the effective dose to an adult is calculated, having anatomically matched the scanned regions of the child and the adult and also matched the irradiation conditions. A conversion factor is then applied to the adult effective dose, based on the region of the body being scanned - head, upper or lower trunk. This conversion factor is the child-to-adult ratio of the ratios of effective dose per entrance air kerma (in the absence of the patient) at the FAD. The values of these conversion factors were calculated by deriving effective dose per entrance air kerma at the FAD for new-born, 1, 5, 10, 15 and adult phantoms using four projections (AP, PA, left and right laterals) over a range of beam qualities and FADs.The program PCXMC was used for this purpose. Results to date suggest that the conversion factors to give effective doses for children undergoing CT examinations of the upper trunk are approximately 1.3, 1.2, 1.15, 1.1 and 1.05 for ages 0, 1, 5, 10 and 15 years respectively; CT of the lower trunk - 1.4, 1.3, 1.2, 1.2, 1.1; and CT of the head - 2.3, 2.0, 1.5, 1.3, 1.1. The dependence of these factors on beam quality (HVL from 4 to 10 mm Al) is less than 10%, with harder beams resulting in slightly smaller conversion factors. Dependence on FAD is also less than 10%. Major sources of uncertainties in the conversion factors include matching anatomical regions across the phantoms, and the presence of beam divergence in the z-direction when deriving the factors. The method described provides a simple means of estimating effective doses arising from paediatric CT examinations with

Time-Dependent Neutron and Photon Dose-Field Analysis

Energy Technology Data Exchange (ETDEWEB)

Wooten, Hasani Omar [Georgia Inst. of Technology, Atlanta, GA (United States)

2005-08-01

A unique tool is developed that allows the user to model physical representations of complicated glovebox facilities in two dimensions and determine neutral-particle flux and ambient dose-equivalent fields throughout that geometry. The Pandemonium code, originally designed to determine flux and dose-rates only, is improved to include realistic glovebox geometries, time-dependent source and detector positions, time-dependent shielding thickness calculations, time-integrated doses, a representative criticality accident scenario based on time-dependent reactor kinetics, and more rigorous photon treatment. A primary benefit of this work has been an extensive analysis and improvement of the photon model that is not limited to the application described in this thesis. The photon model has been extended in energy range to 10 MeV to include photons from fission and new photon buildup factors have been included that account for the effects of photon buildup at slant-path thicknesses as a function of angle, where the mean free path thickness has been preserved. The overall system of codes is user-friendly and it is directly applicable to facilities such as the plutonium facility at Los Alamos National Laboratory, where high-intensity neutron and photon emitters are regularly used. The codes may be used to determine a priori doses for given work scenarios in an effort to supply dose information to process models which will in turn assist decision makers on ensuring as low as reasonably achievable (ALARA) compliance. In addition, coupling the computational results of these tools with the process model visualization tools will help to increase worker safety and radiological safety awareness.

Dose/dose-rate responses of shrimp larvae to UV-B radiation

International Nuclear Information System (INIS)

Damkaer, D.M.

1981-01-01

Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm -2 sub([DNA]) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm -2 sub([DNA]). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation. (orig.)

Dose/dose-rate responses of shrimp larvae to UV-B radiation

Energy Technology Data Exchange (ETDEWEB)

Damkaer, D.M.; Dey, D.B.; Heron, G.A.

1981-01-01

Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm/sup -2/sub((DNA)) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm/sup -2/sub((DNA)). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation.

Sensors of absorbed dose of ionizing radiation based on mosfet

Directory of Open Access Journals (Sweden)

Perevertaylo V. L.

2010-10-01

Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

Parotid gland tumors: a comparison of postoperative radiotherapy techniques using three dimensional (3-D) dose distributions and dose-volume histograms (DVH)

International Nuclear Information System (INIS)

Yaparpalvi, R.; Tyerech, S.K.; Boselli, L.R.; Fontenla, D.P.; Beitler, J.J.; Vikram, B.

1996-01-01

Purpose/Objective: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Materials and Methods: Twenty patients previously treated postoperatively for parotid gland tumors were retrospectively reviewed. Average field size was 9 x 11 cm, average separation was 15.5 cm, and the average prescription depth was 4.5 cm. Using 3-D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and DVH, nine treatment techniques were compared using a representative patient. The treatment techniques investigated were: [1] unilateral 6 MV photons. [2] unilateral 12 MeV electrons. [3] unilateral 16 MeV electrons. [4] a ipsilateral wedge pair technique using 6 MV photons and a 45-degree wedge. [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons. [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting). [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting). [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting). [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥30% of the prescribed dose was 100% for techniques [1], [8] and [9], and <5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1] and [8] contributed to ≥50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed

Mercure IV code application to the external dose computation from low and medium level wastes

International Nuclear Information System (INIS)

Tomassini, T.

1985-01-01

In the present work the external dose from low and medium level wastes is calculated using MERCURE IV code. The code utilizes MONTECARLO method for integrating multigroup line of sight attenuation Kernels

Non-intercepted dose errors in prescribing anti-neoplastic treatment

DEFF Research Database (Denmark)

Mattsson, T O; Holm, B; Michelsen, H

2015-01-01

BACKGROUND: The incidence of non-intercepted prescription errors and the risk factors involved, including the impact of computerised order entry (CPOE) systems on such errors, are unknown. Our objective was to determine the incidence, type, severity, and related risk factors of non-intercepted pr....... Strategies to prevent future prescription errors could usefully focus on integrated computerised systems that can aid dose calculations and reduce transcription errors between databases....

Absorbed dose in CT. Comparison by CT dose index

International Nuclear Information System (INIS)

Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

2002-01-01

Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

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...

The benefit of accounting for DQE variations in simulated dose reduction of digital radiographic systems

International Nuclear Information System (INIS)

Svalkvist, A.; Baath, M.

2010-01-01

Adding noise to clinical radiographs to simulate dose reduction can be used to investigate the relationship between dose level and clinical image quality without exposing patients to additional radiation. The purpose of the present paper was to examine the benefits of using a method that accounts for detective quantum efficiency (DQE) variations that may occur in different dose ranges in the simulated dose reduction process. A method initially intended for simulated dose reduction in tomo-synthesis was applied to extremely low-dose posterio-anterior radiographs of an anthropomorphic chest phantom, selected from a group of projection images included in a tomo-synthesis examination and compared with a previous method that do not account for DQE variations. A comparison of images simulated to be collected at a lower dose level (73% of the original dose level) and images actually collected at this lower dose level revealed that the error in the integrated normalised noise power spectrum was smaller than 4% for the method that accounts for DQE variations in the simulated dose reduction, whereas the error was larger than 20% for the previous method. This indicates that an increased validity in dose reduction simulation of digital radiographic systems is obtained with a method accounting for DQE variations. (authors)

Occupational dose assessment and national dose registry system in Iran

International Nuclear Information System (INIS)

Jafari-Zadeh, M.; Nazeri, F.; Hosseini-Pooya, S. M.; Taheri, M.; Gheshlaghi, F.; Kardan, M. R.; Babakhani, A.; Rastkhah, N.; Yousefi-Nejad, F.; Darabi, M.; Oruji, T.; Gholamali-Zadeh, Z.; Karimi-Diba, J.; Kazemi-Movahed, A. A.; Dashti-Pour, M. R.; Enferadi, A.; Jahanbakhshian, M. H.; Sadegh-Khani, M. R.

2011-01-01

This report presents status of external and internal dose assessment of workers and introducing the structure of National Dose Registry System of Iran (NDRSI). As well as types of individual dosemeters in use, techniques for internal dose assessment are presented. Results obtained from the International Atomic Energy Agency intercomparison programme on measurement of personal dose equivalent H p (10) and consistency of the measured doses with the delivered doses are shown. Also, implementation of dosimetry standards, establishment of quality management system, authorisation and approval procedure of dosimetry service providers are discussed. (authors)

Total dose hardness of a commercial SiGe BiCMOS technology

International Nuclear Information System (INIS)

Van Vonno, N.; Lucas, R.; Thornberry, D.

1999-01-01

Over the past decade SiGe HBT technology has progress from the laboratory to actual commercial applications. When integrated into a BiMOS process, this technology has applications in low-cost space systems. In this paper, we report results of total dose testing of a SiGe/CMOS process accessible through a commercial foundry. (authors)

The Sandia total-dose estimator: SANDOSE description and user guide

International Nuclear Information System (INIS)

Turner, C.D.

1995-02-01

The SANdia total-DOSe Estimator (SANDOSE) is used to estimate total radiation dose to a (BRL-CAT) solid model, SANDOSE uses the mass-sectoring technique to sample the model using ray-tracing techniques. The code is integrated directly into the BRL-CAD solid model editor and is operated using a simple graphical user interface. Several diagnostic tools are available to allow the user to analyze the results. Based on limited validation using several benchmark problems, results can be expected to fall between a 10% underestimate and a factor of 2 overestimate of the actual dose predicted by rigorous radiation transport techniques. However, other situations may be encountered where the results might fall outside of this range. The code is written in C and uses X-windows graphics. It presently runs on SUN SPARCstations, but in theory could be ported to any workstation with a C compiler and X-windows. SANDOSE is available via license by contacting either the Sandia National Laboratories Technology Transfer Center or the author

Effects of indoor residence on radiation doses from routine releases of radionuclides to the atmosphere

International Nuclear Information System (INIS)

Kocher, D.C.

1980-01-01

Dose reduction factors from indoor residence during routine releases of radionuclides to the atmosphere were studied using models that are suitable for application to arbitrary source terms. Dose reduction factors for internal exposure to inhaled radionuclides account for air ventilation and deposition on inside building surfaces. Estimated internal dose reduction factors are approx. 0.2 to 0.8 for particulates and 0.07 to 0.4 for radioiodine. Dose reduction factors for external photon exposure from airborne and surface-deposited sources are based on the point-kernel integration method. Values for source terms from a fuel reprocessing plant and a hypothetical reactor accident are within a factor of 2 of the value 0.5 adopted by the US Nuclear Regulatory Commission (NRC) for population dose assessments. For the release at Three Mile Island nuclear station, however, the external dose reduction factor may be an order of magnitude less than the value adopted by the NRC

Review of European research trends of low dose radiation risk

International Nuclear Information System (INIS)

Iwasaki, Toshiyasu; Yoshida, Kazuo

2010-01-01

Large research projects on low dose radiation effects in Europe and US over the past decade have provided limited scientific knowledge which could underpin the validation of radiation protection systems. Recently in Europe, there have been repeated discussions and dialogues to improve the situation, and as the consequence, the circumstances surrounding low dose radiation risks are changing. In 2009, Multidisciplinary European Low Dose Initiative (MELODI) was established as a trans-national organization capable of ensuring appropriate governance of research in the pursuit of a long term shared vision, and Low Dose Research towards Multidisciplinary Integration (DoReMi) network was launched in 2010 to achieve fairly short term results in order to prove the validity of the MELODI approach. It is expected to be very effective and powerful activities to facilitate the reduction of uncertainties in the understanding of low dose risks, but the regulatory requests rushing the reinforcement of radiological protection regulations based on the precautional principles are more increasing. To develop reasonable radiological protection systems based on scientific evidences, we need to accelerate to collect scientific evidences which could directly underpin more appropriate radiation protection systems even in Japan. For the purpose, we Japan need to develop from an independent standpoint and share as a multidisciplinary vision a long term and holistic research strategy which enables to enhance Japanese advantages such as low dose rate facilities and animal facilities, as soon as possible. (author)

Dose assessment activities in the Republic of the Marshall Islands

International Nuclear Information System (INIS)

Simon, S.L.; Graham, J.C.

1996-01-01

Dose assessments, both retrospective and prospective, comprise one important function of a radiological study commissioned by the Republic of the Marshall Islands (RMI) government in late 1989. Estimating past or future exposure requires the synthesis of information from historical data, results from a recently completed field monitoring program, laboratory measurements, and some experimental studies. Most of the activities in the RMI to date have emphasized a pragmatic rather than theoretical approach. In particular, most of the recent effort has been expended on conducting an independent radiological monitoring program to determine the degree of deposition and the geographical extent of weapons test fallout over the nation. Contamination levels on 70% of the land mass of the Marshall Islands were unknown prior to 1994. The environmental radioactivity data play an integral role in both retrospective and prospective assessments. One recent use of dose assessment has been to interpret environmental measurements of radioactivity into annual doses that might be expected at every atoll. A second use for dose assessment has been to determine compliance with dose action level for the rehabitation of Rongelap Island. Careful examination of exposure pathways relevant to the island lifestyle has been necessary to accommodate these purposes. Finally, an examination is underway of gummed film, fixed-instrument, and aerial survey data accumulated during the 1950's by the Health and Safety Laboratory of the U.S. AEC. This article gives an overview of these many different activities and a summary of recent dose assessments

What is correct: equivalent dose or dose equivalent

International Nuclear Information System (INIS)

Franic, Z.

1994-01-01

In Croatian language some physical quantities in radiation protection dosimetry have not precise names. Consequently, in practice either terms in English or mathematical formulas are used. The situation is even worse since the Croatian language only a limited number of textbooks, reference books and other papers are available. This paper compares the concept of ''dose equivalent'' as outlined in International Commission on Radiological Protection (ICRP) recommendations No. 26 and newest, conceptually different concept of ''equivalent dose'' which is introduced in ICRP 60. It was found out that Croatian terminology is both not uniform and unprecise. For the term ''dose equivalent'' was, under influence of Russian and Serbian languages, often used as term ''equivalent dose'' even from the point of view of ICRP 26 recommendations, which was not justified. Unfortunately, even now, in Croatia the legal unit still ''dose equivalent'' defined as in ICRP 26, but the term used for it is ''equivalent dose''. Therefore, in Croatian legislation a modified set of quantities introduced in ICRP 60, should be incorporated as soon as possible

Development on Dose Assessment Model of Northeast Asia Nuclear Accident Simulator

Energy Technology Data Exchange (ETDEWEB)

Kim, Ju Yub; Kim, Ju Youl; Kim, Suk Hoon; Lee, Seung Hee; Yoon, Tae Bin [FNC Techology, Yongin (Korea, Republic of)

2016-05-15

In order to support the emergency response system, the simulator for overseas nuclear accident is under development including source-term estimation, atmospheric dispersion modeling and dose assessment. The simulator is named NANAS (Northeast Asia Nuclear Accident Simulator). For the source-term estimation, design characteristics of each reactor type should be reflected into the model. Since there are a lot of reactor types in neighboring countries, the representative reactors of China, Japan and Taiwan have been selected and the source-term estimation models for each reactor have been developed, respectively. For the atmospheric dispersion modeling, Lagrangian particle model will be integrated into the simulator for the long range dispersion modeling in Northeast Asia region. In this study, the dose assessment model has been developed considering external and internal exposure. The dose assessment model has been developed as a part of the overseas nuclear accidents simulator which is named NANAS. It addresses external and internal pathways including cloudshine, groundshine and inhalation. Also, it uses the output of atmospheric dispersion model (i.e. the average concentrations of radionuclides in air and ground) and various coefficients (e.g. dose conversion factor and breathing rate) as an input. Effective dose and thyroid dose for each grid in the Korean Peninsula region are printed out as a format of map projection and chart. Verification and validation on the dose assessment model will be conducted in further study by benchmarking with the measured data of Fukushima Daiichi Nuclear Accident.

Dose prescription in boron neutron capture therapy

International Nuclear Information System (INIS)

Gupta, N.M.S.; Gahbauer, R.A.; Blue, T.E.; Wambersie, A.

1994-01-01

The purpose of this paper is to address some aspects of the many considerations that need to go into a dose prescription in boron neutron capture therapy (BNCT) for brain tumors; and to describe some methods to incorporate knowledge from animal studies and other experiments into the process of dose prescription. Previously, an algorithm to estimate the normal tissue tolerance to mixed high and low linear energy transfer radiations in BNCT was proposed. The authors have developed mathematical formulations and computational methods to represent this algorithm. Generalized models to fit the central axis dose rate components for an epithermal neutron field were also developed. These formulations and beam fitting models were programmed into spreadsheets to simulate two treatment techniques which are expected to be used in BNCT: a two-field bilateral scheme and a single-field treatment scheme. Parameters in these spreadsheets can be varied to represent the fractionation scheme used, the 10 B microdistribution in normal tissue, and the ratio of 10 B in tumor to normal tissue. Most of these factors have to be determined for a given neutron field and 10 B compound combination from large animal studies. The spreadsheets have been programmed to integrate all of the treatment-related information and calculate the location along the central axis where the normal tissue tolerance is exceeded first. This information is then used to compute the maximum treatment time allowable and the maximum tumor dose that may be delivered for a given BNCT treatment. The effect of different treatment variables on the treatment time and tumor dose has been shown to be very significant. It has also been shown that the location of D max shifts significantly, depending on some of the treatment variables-mainly the fractionation scheme used. These results further emphasize the fact that dose prescription in BNCT is very complicated and nonintuitive. 11 refs., 6 figs., 3 tabs

A study of the annual doses to man from routine gaseous effluent releases of the Philippine Nuclear Power Plant Unit 1 (PNPP-1)

International Nuclear Information System (INIS)

Noriel, M.C.J.

1983-01-01

Individual and population integrated doses from radioactive gaseous releases of the Philippine Nuclear Power Plant 1 (PNPP-1) were calculated using a modified GASPAR Code. Input data consisted of meteorological and site data gathered from the PNPP-1 Final Analysis Report (FASR) population and agricultural data from the National Economic and Development Authority (NEDA) and the National Census and Statistics Office (NCSO). Usage factors were calculated based on Food and Nutrition Research Institute (FNRI) recommended dietary allowances for Filipinos. Results of population integrated dose calculations were used in identifying the critical nuclides, the critical body organs, and the critical pathway. Results from individual dose calculation were used in determining compliance with the dose limits set forth in Appendix D of Part 7 Code of Philippine Atomic Energy Commission (PAEC) regulations. (Author). 23 tabs.; 5 figs

Dose volume assessment of high dose rate 192IR endobronchial implants

International Nuclear Information System (INIS)

Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

1996-01-01

Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

The effects of different doses of IGF-1 on cartilage and subchondral bone during the repair of full-thickness articular cartilage defects in rabbits.

Science.gov (United States)

Zhang, Z; Li, L; Yang, W; Cao, Y; Shi, Y; Li, X; Zhang, Q

2017-02-01

To investigate the effects of different doses of insulin-like growth factor 1 (IGF-1) on the cartilage layer and subchondral bone (SB) during repair of full-thickness articular cartilage (AC) defects. IGF-1-loaded collagen membrane was implanted into full-thickness AC defects in rabbits. The effects of two different doses of IGF-1 on cartilage layer and SB adjacent to the defect, the cartilage structure, formation and integration, and the new SB formation were evaluated at the 1st, 4th and 8th week postoperation. Meanwhile, after 1 week treatment, the relative mRNA expressions in tissues adjacent to the defect, including cartilage and SB were determined by quantitative real-time RT-PCR (qRT-PCR), respectively. Different doses of IGF-1 induced different gene expression profiles in tissues adjacent to the defect and resulted in different repair outcomes. Particularly, at high dose IGF-1 aided cell survival, regulated the gene expressions in cartilage layer adjacent defect and altered ECM composition more effectively, improved the formation and integrity of neo-cartilage. While, at low dose IGF-1 regulated the gene expressions in SB more efficaciously and subsequently promoted the SB remodeling and reconstruction. Different doses of IGF-1 induced different responses of cartilage or SB during the repair of full-thickness AC defects. Particularly, high dose of IGF-1 was more beneficial to the neo-cartilage formation and integration, while low dose of it was more effective for the SB formation. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

An updated dose assessment for resettlement options at Bikini Atoll--a U.S. nuclear test site.

Science.gov (United States)

Robison, W L; Bogen, K T; Conrado, C L

1997-07-01

On 1 March 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as part of our continuing research and monitoring program that began in 1978. The unique composition of coral soil greatly alters the relative contribution of 137Cs and 90Sr to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, 137Cs produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1999. The estimated maximum annual effective dose for current island conditions is 4.0 mSv when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 91 mSv, 130 mSv, and 150 mSv, respectively. A detailed uncertainty analysis for these dose estimates is presented in a companion paper in this issue. We have evaluated various countermeasures to reduce 137Cs in food crops. Treatment with potassium reduces the uptake of 137Cs into food crops, and therefore the ingestion dose, to about 5% of pretreatment levels and has essentially no negative environmental consequences. We have calculated the dose for the rehabilitation scenario where the top 40 cm of soil is removed in the housing and village area, and the rest of the island is treated with potassium fertilizer; the maximum annual effective dose is 0.41 mSv and the 30-, 50-, and 70-y

Contribution of maternal radionuclide burdens to prenatal radiation doses

International Nuclear Information System (INIS)

Sikov, M.R.; Hui, T.E.

1996-05-01

This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 μCi into a woman's blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in the report to provide for use in operational radiological protection situations. These approaches to calculation yield radiation absorbed doses that can be converted to dose equivalent by multiplication by quality factor. Dose equivalent is the most common quantity for stating prenatal dose limits in the United States and is appropriate for the types of effect that are usually associated with prenatal exposure. If it is desired to obtain alternatives for other purposes, this value can be multiplied by appropriate weighting factors

Contribution of maternal radionuclide burdens to prenatal radiation doses

Energy Technology Data Exchange (ETDEWEB)

Sikov, M.R.; Hui, T.E.

1996-05-01

This report describes approaches to calculating and expressing radiation doses to the embryo/fetus from internal radionuclides. Information was obtained for selected, occupationally significant radioelements that provide a spectrum of metabolic and dosimetric characteristics. Evaluations are also presented for inhaled inert gases and for selected radiopharmaceuticals. Fractional placental transfer and/or ratios of concentration in the embryo/fetus to that in the woman were calculated for these materials. The ratios were integrated with data from biokinetic transfer models to estimate radioactivity levels in the embryo/fetus as a function of stage of pregnancy and time after entry into the transfer compartment or blood of the pregnant woman. These results are given as tables of deposition and retention in the embryo/fetus as a function of gestational age at exposure and elapsed time following exposure. Methodologies described by MIRD were extended to formalize and describe details for calculating radiation absorbed doses to the embryo/fetus. Calculations were performed using a model situation that assumed a single injection of 1 {mu}Ci into a woman`s blood; independent calculations were performed for administration at successive months of pregnancy. Gestational -stage-dependent dosimetric tabulations are given together with tables of correlations and relationships. Generalized surrogate dose factors and categorizations are provided in the report to provide for use in operational radiological protection situations. These approaches to calculation yield radiation absorbed doses that can be converted to dose equivalent by multiplication by quality factor. Dose equivalent is the most common quantity for stating prenatal dose limits in the United States and is appropriate for the types of effect that are usually associated with prenatal exposure. If it is desired to obtain alternatives for other purposes, this value can be multiplied by appropriate weighting factors.

MRI dosimetry using an echo-quotient technique for high dose rate brachytherapy

International Nuclear Information System (INIS)

Ansbacher, W.

1996-01-01

MRI gel dosimetry is a relatively new technique that has many advantages over conventional methods, and is particularly suited to High Dose Rate (HDR) Brachytherapy. The dosimeter has high spatial resolution and a water-equivalent response over a wide range of photon energies. Because it is an integrating dosimeter, it allows for efficient mapping of the dynamically-produced distributions from an HDR source. As an example of this technique, the dose response, which is calibrated in terms of the change in spin-spin relaxation time, has been used to investigate the anisotropy of an HDR source. (author). 1 fig

ANDROS: A code for Assessment of Nuclide Doses and Risks with Option Selection

International Nuclear Information System (INIS)

Begovich, C.L.; Sjoreen, A.L.; Ohr, S.Y.; Chester, R.O.

1986-11-01

ANDROS (Assessment of Nuclide Doses and Risks with Option Selection) is a computer code written to compute doses and health effects from atmospheric releases of radionuclides. ANDROS has been designed as an integral part of the CRRIS (Computerized Radiological Risk Investigation System). ANDROS reads air concentrations and environmental concentrations of radionuclides to produce tables of specified doses and health effects to selected organs via selected pathways (e.g., ingestion or air immersion). The calculation may be done for an individual at a specific location or for the population of the whole assessment grid. The user may request tables of specific effects for every assessment grid location. Along with the radionuclide concentrations, the code requires radionuclide decay data, dose and risk factors, and location-specific data, all of which are available within the CRRIS. This document is a user manual for ANDROS and presents the methodology used in this code

Using RADFET for the real-time measurement of gamma radiation dose rate

Science.gov (United States)

Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

2015-02-01

RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h-1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

Using RADFET for the real-time measurement of gamma radiation dose rate

International Nuclear Information System (INIS)

Andjelković, Marko S; Ristić, Goran S; Jakšić, Aleksandar B

2015-01-01

RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0 , 10 , 20  and 30 V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65  to 32.1 Gy h −1 and up to the total absorbed dose of 25 Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose. (paper)

A novel dose uncertainty model and its application for dose verification

International Nuclear Information System (INIS)

Jin Hosang; Chung Heetaek; Liu Chihray; Palta, Jatinder; Suh, Tae-Suk; Kim, Siyong

2005-01-01

Based on statistical approach, a novel dose uncertainty model was introduced considering both nonspatial and spatial dose deviations. Non-space-oriented uncertainty is mainly caused by dosimetric uncertainties, and space-oriented dose uncertainty is the uncertainty caused by all spatial displacements. Assuming these two parts are independent, dose difference between measurement and calculation is a linear combination of nonspatial and spatial dose uncertainties. Two assumptions were made: (1) the relative standard deviation of nonspatial dose uncertainty is inversely proportional to the dose standard deviation σ, and (2) the spatial dose uncertainty is proportional to the gradient of dose. The total dose uncertainty is a quadratic sum of the nonspatial and spatial uncertainties. The uncertainty model provides the tolerance dose bound for comparison between calculation and measurement. In the statistical uncertainty model based on a Gaussian distribution, a confidence level of 3σ theoretically confines 99.74% of measurements within the bound. By setting the confidence limit, the tolerance bound for dose comparison can be made analogous to that of existing dose comparison methods (e.g., a composite distribution analysis, a γ test, a χ evaluation, and a normalized agreement test method). However, the model considers the inherent dose uncertainty characteristics of the test points by taking into account the space-specific history of dose accumulation, while the previous methods apply a single tolerance criterion to the points, although dose uncertainty at each point is significantly different from others. Three types of one-dimensional test dose distributions (a single large field, a composite flat field made by two identical beams, and three-beam intensity-modulated fields) were made to verify the robustness of the model. For each test distribution, the dose bound predicted by the uncertainty model was compared with simulated measurements. The simulated

Global collective dose commitments from release of long-lived radionuclides. Differential cost-benefit considerations

International Nuclear Information System (INIS)

Gjoerup, H.L.

1977-01-01

The concept of global collective dose commitment as a measure of total detriment from the release of radioactivity to the environment is outlined. Estimates are given of global collective dose commitments resulting from the release of 14 C and uranium daughter products from the nuclear fuel cycle. Comparisons are made with similar estimates of global collective dose commitments resulting from the use of fossil fuels and certain fertilizers due to their content of uranium and its daughter products. In the case of long-lived radionuclides that remain in circulation in the biosphere, it is shown that the use of global collective dose commitments in differential cost-benefit analysis can lead to questionable results. In differential cost-benefit analysis it is suggested that population exposures should not simply be integrated irrespective of their time of occurrence, but that a certain discount rate should be applied for future doses. This suggestion is examined. (author)

Organ-specific external dose coefficients and protective apron transmission factors for historical dose reconstruction for medical personnel.

Science.gov (United States)

Simon, Steven L

2011-07-01

ICRP/ICRU mono-energetic DCCs and the functions integrated over the air-kerma weighted photon fluence of the 12 defined x-ray spectra. The air kerma-weighted DCCs in this work were developed specifically for an irradiation geometry of anterior to posterior (AP) and for the following tissues: thyroid, breast, ovary, lens of eye, lung, colon, testes, heart, skin (anterior side only), red bone marrow (RBM), and brain. In addition, a series of functional relationships to predict DT Ka-1 values for RBM dependent on body mass index [BMI (kg m-2) ≡ weight per height] and average photon energy were derived from a published analysis. Factors to account for attenuation of radiation by protective lead aprons were also developed. Because lead protective aprons often worn by radiology personnel not only reduce the intensity of x-ray exposure but also appreciably harden the transmitted fluence of bremsstrahlung x-rays, DCCs were separately calculated for organs possibly protected by lead aprons by considering three cases: no apron, 0.25 mm Pb apron, and 0.5 mm Pb apron. For estimation of organ doses from conducting procedures with radioisotopes, continuous functions of the reported mono-energetic values were developed, and DCCs were derived by estimation of the function at relevant energies. By considering the temporal changes in primary exposure-related parameters (e.g., energy distribution), the derived DCCs and transmission factors presented here allow for more realistic historical dose reconstructions for medical personnel when monitoring badge readings are the primary data on which estimation of an individual's organ doses are based.

Integrated analysis of genetic variation and gene expression reveals novel variant for increased warfarin dose requirement in African Americans

NARCIS (Netherlands)

Hernandez, W.; Gamazon, E. R.; Aquino-Michaels, K.; Smithberger, E.; O'Brien, T. J.; Harralson, A. F.; Tuck, M.; Barbour, A.; Cavallari, L. H.; Perera, M. A.

2017-01-01

Essentials Genetic variants controlling gene regulation have not been explored in pharmacogenomics. We tested liver expression quantitative trait loci for association with warfarin dose response. A novel predictor for increased warfarin dose response in African Americans was identified. Precision

Intensity-Modulated Radiotherapy for Craniospinal Irradiation: Target Volume Considerations, Dose Constraints, and Competing Risks

International Nuclear Information System (INIS)

Parker, William; Filion, Edith; Roberge, David; Freeman, Carolyn R.

2007-01-01

Purpose: To report the results of an analysis of dose received to tissues and organs outside the target volume, in the setting of spinal axis irradiation for the treatment of medulloblastoma, using three treatment techniques. Methods and Materials: Treatment plans (total dose, 23.4 Gy) for a standard two-dimensional (2D) technique, a three-dimensional (3D) technique using a 3D imaging-based target volume, and an intensity-modulated radiotherapy (IMRT) technique, were compared for 3 patients in terms of dose-volume statistics for target coverage, as well as organ at risk (OAR) and overall tissue sparing. Results: Planning target volume coverage and dose homogeneity was superior for the IMRT plans for V 95% (IMRT, 100%; 3D, 96%; 2D, 98%) and V 107% (IMRT, 3%; 3D, 38%; 2D, 37%). In terms of OAR sparing, the IMRT plan was better for all organs and whole-body contour when comparing V 10Gy , V 15Gy , and V 20Gy . The 3D plan was superior for V 5Gy and below. For the heart and liver in particular, the IMRT plans provided considerable sparing in terms of V 10Gy and above. In terms of the integral dose, the IMRT plans were superior for liver (IMRT, 21.9 J; 3D, 28.6 J; 2D, 38.6 J) and heart (IMRT, 9 J; 3D, 14.1J; 2D, 19.4 J), the 3D plan for the body contour (IMRT, 349 J; 3D, 337 J; 2D, 555 J). Conclusions: Intensity-modulated radiotherapy is a valid treatment option for spinal axis irradiation. We have shown that IMRT results in sparing of organs at risk without a significant increase in integral dose

A dose error evaluation study for 4D dose calculations

Science.gov (United States)

Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

2014-10-01

Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

International Nuclear Information System (INIS)

McLaughlin, W.L.

1985-01-01

Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

Nominal Performance Biosphere Dose Conversion Factor Analysis

International Nuclear Information System (INIS)

Wasiolek, M.

2000-01-01

The purpose of this report was to document the process leading to development of the Biosphere Dose Conversion Factors (BDCFs) for the postclosure nominal performance of the potential repository at Yucca Mountain. BDCF calculations concerned twenty-four radionuclides. This selection included sixteen radionuclides that may be significant nominal performance dose contributors during the compliance period of up to 10,000 years, five additional radionuclides of importance for up to 1 million years postclosure, and three relatively short-lived radionuclides important for the human intrusion scenario. Consideration of radionuclide buildup in soil caused by previous irrigation with contaminated groundwater was taken into account in the BDCF development. The effect of climate evolution, from the current arid conditions to a wetter and cooler climate, on the BDCF values was evaluated. The analysis included consideration of different exposure pathway's contribution to the BDCFs. Calculations of nominal performance BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. BDCFs for the nominal performance, when combined with the concentrations of radionuclides in groundwater allow calculation of potential radiation doses to the receptor of interest. Calculated estimates of radionuclide concentration in groundwater result from the saturated zone modeling. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA) to calculate doses to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain

Biological influence from low dose and low-dose rate radiation

International Nuclear Information System (INIS)

Magae, Junji

2007-01-01

Although living organisms have defense mechanisms for radioadaptive response, the influence is considered to vary qualitatively and quantitatively for low dose and high dose, as well as for low-dose rate and high-dose rate. This article describes the bioresponse to low dose and low-dose rate. Among various biomolecules, DNA is the most sensitive to radiation, and accurate replication of DNA is an essential requirement for the survival of living organisms. Also, the influence of active enzymes resulted from the effect of radiation on enzymes in the body is larger than the direct influence of radiation on the body. After this, the article describes the carcinogenic risk by low-dose radiation, and then so-called Hormesis effect to create cancer inhibition effect by stimulating active physiology. (S.K.)

Overview of Graphical User Interface for ARRBOD (Acute Radiation Risk and BRYNTRN Organ Dose Projection)

Science.gov (United States)

Kim, Myung-Hee Y.; Hu, Shaowen; Nounu, Hatem N.; Cucinotta, Francis A.

2010-01-01

Solar particle events (SPEs) pose the risk of acute radiation sickness (ARS) to astronauts, because organ doses from large SPEs may reach critical levels during extra vehicular activities (EVAs) or lightly shielded spacecraft. NASA has developed an organ dose projection model of Baryon transport code (BRYNTRN) with an output data processing module of SUMDOSE, and a probabilistic model of acute radiation risk (ARR). BRYNTRN code operation requires extensive input preparation, and the risk projection models of organ doses and ARR take the output from BRYNTRN as an input to their calculations. With a graphical user interface (GUI) to handle input and output for BRYNTRN, these response models can be connected easily and correctly to BRYNTRN in a user friendly way. The GUI for the Acute Radiation Risk and BRYNTRN Organ Dose (ARRBOD) projection code provides seamless integration of input and output manipulations required for operations of the ARRBOD modules: BRYNTRN, SUMDOSE, and the ARR probabilistic response model. The ARRBOD GUI is intended for mission planners, radiation shield designers, space operations in the mission operations directorate (MOD), and space biophysics researchers. Assessment of astronauts organ doses and ARS from the exposure to historically large SPEs is in support of mission design and operation planning to avoid ARS and stay within the current NASA short-term dose limits. The ARRBOD GUI will serve as a proof-of-concept for future integration of other risk projection models for human space applications. We present an overview of the ARRBOD GUI product, which is a new self-contained product, for the major components of the overall system, subsystem interconnections, and external interfaces.

Superficial dose evaluation of four dose calculation algorithms

Science.gov (United States)

Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

2017-08-01

Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

A study on development of Pyro process integrated inactive demonstration facility

International Nuclear Information System (INIS)

Cho, I.; Lee, E.; Choung, W.; You, G.; Kim, H.

2010-10-01

Since 2007, the Pride (Pyro process integrated inactive demonstration facility) has been developed to demonstrate the integrated engineering-scale pyro processing using natural uranium with surrogate materials. In this paper, safety evaluation on hypothetical accident case is carried out to ensure the release of radioactivity being negligible to the environment and the performance of indoor argon flow for the argon cell has been investigated by means of CFD analysis. The worst accident case, even in the firing of the all uranium metal in argon cell, cause dose rate are negligible comparing to 0.25 Sv of effective dose rate to whole body or 3 Sv of equivalent dose rate to the thyroid preliminary CFD analyses show the temperature and velocity distribution of argon cell, and give the information to change the argon exchange rate and displace the argon supply or exhaust duct. CFD will allow design change and improvements in ventilation systems at lower cost. (Author)

Total dose induced latch in short channel NMOS/SOI transistors

International Nuclear Information System (INIS)

Ferlet-Cavrois, V.; Quoizola, S.; Musseau, O.; Flament, O.; Leray, J.L.; Pelloie, J.L.; Raynaud, C.; Faynot, O.

1998-01-01

A latch effect induced by total dose irradiation is observed in short channel SOI transistors. This effect appears on NMOS transistors with either a fully or a partially depleted structure. It is characterized by a hysteresis behavior of the Id-Vg characteristics at high drain bias for a given critical dose. Above this dose, the authors still observe a limited leakage current at low drain bias (0.1 V), but a high conduction current at high drain bias (2 V) as the transistor should be in the off-state. The critical dose above which the latch appears strongly depends on gate length, transistor structure (fully or partially depleted), buried oxide thickness and supply voltage. Two-dimensional (2D) numerical simulations indicate that the parasitic condition is due to the latch of the back gate transistor triggered by charge trapping in the buried oxide. To avoid the latch induced by the floating body effect, different techniques can be used: doping engineering, body contacts, etc. The study of the main parameters influencing the latch (gate length, supply voltage) shows that the scaling of technologies does not necessarily imply an increased latch sensitivity. Some technological parameters like the buried oxide hardness and thickness can be used to avoid latch, even at high cumulated dose, on highly integrated SOI technologies

Hematological toxicity in radioimmunotherapy is predicted both by the computed absorbed whole body dose (cGy) and by the administered dose (mCi)

International Nuclear Information System (INIS)

Marquez, Sheri D.; Knox, Susan J.; Trisler, Kirk D.; Goris, Michael L.

1997-01-01

Purpose/Objective: Radioimmunotherapy (RIT) has yielded encouraging response rates in patients with recurrent non-Hodgkin's lymphoma, but myelotoxicity remains the dose limiting factor. Dose optimization is theoretically possible, since a pretreatment biodistribution study with tracer doses allows for a fairly accurate estimate of the whole body (and by implication the bone marrow) dose in patients. It has been shown that the radiation dose as a function of the administered dose varies widely from patient to patient. The pretreatment study could therefore be used to determine the maximum tolerable dose for each individual patient. The purpose of this study was to examine whether the administered dose or the estimated whole body absorbed radiation dose were indeed predictors of bone marrow toxicity. Materials and Methods: We studied two cohorts of patients to determine if the computed integral whole body or marrow dose is predictive of myelotoxicity. The first cohort consisted of 13 patients treated with Yttrium-90 labeled anti-CD20 (2B8) monoclonal antibody. Those patients were treated in a dose escalation protocol, based on the administered dose, without correction for weight or body surface. The computed whole body dose varied from 41 to 129 cGy. The second cohort (6 patients) were treated with Iodine-131 labeled anti-CD20 (B1) antibody. In this group the administered dose was tailored to deliver an estimated 75 cGy whole body dose. The administered dose varied from 54 to 84 mCi of Iodine-131. For each patient, white blood cell count with differential, hemoglobin, hematocrit, and platelet levels were measured before and at regular intervals after RIT was administered. Using linear regression analysis, a relationship between administered dose, absorbed dose and myelotoxicity was determined for each patient cohort. Results: Marrow toxicity was measured by the absolute decrease in white blood cell (DWBC), platelet (DPLAT), and neutrophil (DN) values. In the Yttrium

Biological dose estimation for accidental supra-high dose gamma-ray exposure

International Nuclear Information System (INIS)

Chen, Y.; Yan, X.K.; Du, J.; Wang, Z.D.; Zhang, X.Q.; Zeng, F.G.; Zhou, P.K.

2011-01-01

To correctly estimate the biological dose of victims accidentally exposed to a very high dose of 60 Co gamma-ray, a new dose-effect curve of chromosomal dicentrics/multicentrics and rings in the supra-high dose range was established. Peripheral blood from two healthy men was irradiated in vitro with doses of 60 Co gamma-rays ranging from 6 to 22 Gy at a dose rate of 2.0 Gy/min. Lymphocytes were concentrated, cultured and harvested at 52 h, 68 h and 72 h. The numbers of dic + r were counted. The dose-effect curves were established and validated using comparisons with doses from the Tokai-mura accident and were then applied to two victims of supra-high dose exposure accident. The results indicated that there were no significant differences in chromosome aberration frequency among the different culture times from 52 h to 72 h. The 6-22 Gy dose-effect curve was fitted to a linear quadratic model Y = -2.269 + 0.776D - 7.868 x l0 -3 D 2 . Using this mathematic model, the dose estimates were similar to data from Tokai-mura which were estimated by PCC ring. Whole body average doses of 9.7 Gy and 18.1 Gy for two victims in the Jining accident were satisfactorily given. We established and successfully applied a new dose-effect curve of chromosomal dicentrics plus ring (dic + r) after 6-22 Gy γ-irradiation from a supra-high dose 60 Co gamma-ray accident.