Measurement of the radiation in the accelerator-therapy room

International Nuclear Information System (INIS)

Zutz, Hayo

2013-01-01

The measurement of the scattering radiation in the accelerator-therapy room of the PTB is described. The accelerators are commercial linear accelerators of the firm Elektra of the type ''Precise''. The measurements were performed by means of secondary-normal ionization chambers and a special measurement technique developed in the PTB both with and without the used beam. (HSI)

Dose estimation of the THOR BNCT treatment room

International Nuclear Information System (INIS)

Hsu, F.Y.; Liu, H.M.; Yu, C.C.; Huang, Y.H.; Tsai, H.N.

2006-01-01

BNCT beam of Tsing Hua Open-pool Reactor (THOR) was designed and constructed since 1998. A treatment room for the newly modified THOR BNCT beam was constructed for the next clinical-stage trials in 2004. Dose distribution in a patient (or a phantom) is important as irradiated with the BNCT beam. The dose distributions for different type of radiations such as neutron and photons in the treatment room are strongly becoming the index or reference of success for a BNCT facility. An ART head phantom was placed in front of the THOR BNCT beam port and was irradiated. In each section of the head phantom, numbers of small holes are inside and separated uniformly. Dual detector: TLD-600 and TLD-700 chips were placed inside these holes within the phantom to distinct doses of neutron and photon. Besides, Dual-TLD chips were latticed placed in the horizontal plane of beam central axis, in the treatment room to estimate the spatial dose distribution of neutron and photon. Gold foils were assisted in TLD dose calibrations. Neutron and photon dose distributions in phantom and spatial dose distributions in the THOR BNCT treatment room were both estimated in this work. Testing and improvement in THOR BNCT beam were continuative during these years. Results of this work could be the reference and be helpful for the further clinical trials in nearly future. (author)

If additional shielding required for the linear accelerator room when modern treatment techniques are intensively used

International Nuclear Information System (INIS)

Miller, Albert V.; Atkocius, Vydmantas; Aleknavicius, Eduardas

2001-01-01

Full text: Introduction - When the new linear accelerator is to be installed in radiotherapy department the responsible personnel should perform necessary estimations and calculations of the protective barriers for the accelerator treatment room. These methods are described in details in literature. However, if modern treatment techniques are planned to be intensively used on this machine, additional concern rises regarding adequacy of these calculations. The new Saturne-43 linear accelerator with three photon energies of 8, 15 and 25 MV recently installed at our department was, planned to be used for conventional treatment techniques as well as for conformal and total body treatments. The method of conformal therapy generally employs more small fields per one treated patient than conventional techniques. It leads to the use of more linear accelerator monitor units for the average treatment. It was estimated that 'beam on' time of an accelerator to deliver the same dose to the tumor is up to 3 times more than for conventional methods. The total body technique contribute to the extra time on of an accelerator because of extended distance to the dose prescription point. Altogether intensive clinical use of these modern techniques will noticeably increase 'beam on' time of an accelerator and rise question regarding validity of the traditionally calculated shielding of the treatment room. Materials and methods - IAEA-TECDOC-1040 and NCRP Report No 49 suggest considering three main components incident on the protective barriers: direct radiation, scatter radiation and leakage radiation. The formulas for these components are similar and dose equivalent limits are proportional to the workload. For the conventional treatments workloads of direct, scattered and leakage radiation are equal and calculated by the division of total prescribed dose (for all treated per week patients) to the machine isocenter to average tissue maximum ratio. These workloads for conformal and TBI

A novel technique to optimise the length of a linear accelerator treatment room maze without compromising radiation protection.

Science.gov (United States)

Al-Affan, I A M; Evans, S C; Qutub, M; Hugtenburg, R P

2018-03-01

Simulations with the FLUktuierende KAskade (FLUKA) Monte Carlo code were used to establish the possibility of introducing lead to cover the existing concrete walls of a linear accelerator treatment room maze, in order to reduce the dose of the scattered photons at the maze entrance. In the present work, a pilot study performed at Singleton Hospital in Swansea was used to pioneer the use of lead sheets of various thicknesses to absorb scattered low energy photons in the maze. The dose reduction was considered to be due to the strong effect of the photoelectric interaction in lead resulting in attenuation of the back-scattered photons. Calculations using FLUKA with mono-energetic photons were used to represent the main components of the x-ray spectrum up to 10 MV. Mono-energetic photons were used to enable the study of the behaviour of each energy component from the associated interaction processes. The results showed that adding lead of 1 to 4 mm thickness to the walls and floor of the maze reduced the dose at the maze entrance by up to 80%. Subsequent scatter dose measurements performed at the maze entrance of an existing treatment room with lead sheet of 1.3 mm thickness added to the maze walls and floor supported the results from the simulations. The dose reduction at the maze entrance with the lead in place was up to 50%. The variation between simulation and measurement was attributed to the fact that insufficient lead was available to completely cover the maze walls and floor. This novel proposal of partly, or entirely, covering the maze walls with lead a few millimetres in thickness has implications for the design of linear accelerator treatment rooms since it has the potential to provide savings, in terms of space and costs, when an existing maze requires upgrading in an environment where space is limited and the maze length cannot be extended sufficiently to reduce the dose.

Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs; Estudo da radiacao espalhada e produzida pela blindagem de concreto de salas de radioterapia e seus efeitos sobre doses equivalentes nos orgaos dos pacientes

Energy Technology Data Exchange (ETDEWEB)

Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G., E-mail: kelmo.lins@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: sergiogavazza@yahoo.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: ggrprojetos@gmail.com, E-mail: maglosilva15@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Thalhofer, J.L.; Silva, A.X., E-mail: jardellt@yahoo.com.br, E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Energia Nuclear; Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia

2015-07-01

Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

Dose enhancement in a room cobalt-60 source

International Nuclear Information System (INIS)

Simons, M.; Pease, R.L.; Fleetwood, D.M.; Schwank, J.R.; Krzesniak, M.

1997-01-01

A room Co-60 source was characterized using TLDs and pMOS RADFETs. Dose enhancement was measured using RADFETs with and without gold- flashed kovar lids. A methodology was developed to predict dose enhancement vs position and test configuration

Dose field research of analysis room for in-hospital neutron irradiator

International Nuclear Information System (INIS)

Zhang Zizhu; Song Mingzhe; Li Wei; Chen Jun; Yang Yong; Li Yiguo

2012-01-01

Neutron equivalent dose rate and y ray dose rate inside the analysis room of the in-hospital neutron irradiator (IHNI) and outdoor were measured. The results show that γ ray dose rate inside the analysis room exceeds calculation value many times and γ/ ray dose rate outdoor is higher than supervision region dose limit of 7.5 μSv/h. According to the measurement results and the Monte Carlo simulation, the following shielding plan was adopted. Lead shielding with thickness of 16 cm was installed on the wall, which faces the neutron beam, to shield γ ray, and lithium polyethylene plate with thickness of l cm was installed on all the wall (not including ceiling and floor) to shield scattering neutron. After shielding transformation, the highest γ ray dose rate point inside the analysis room decreased 277 times, the neutron equivalent dose rate decreased 5.8 times, and the outdoor γ/ray dose rate decreased nearly 90 times. (authors)

Shielding design of a treatment room for an accelerator-based epithermal neutron irradiation facility for BNCT

International Nuclear Information System (INIS)

Evans, J.F.; Blue, T.E.

1996-01-01

Protecting the facility personnel and the general public from radiation exposure is a primary safety concern of an accelerator-based epithermal neutron irradiation facility. This work makes an attempt at answering the questions open-quotes How much?close quotes and open-quotes What kind?close quotes of shielding will meet the occupational limits of such a facility. Shielding effectiveness is compared for ordinary and barytes concretes in combination with and without borated polyethylene. A calculational model was developed of a treatment room, patient open-quotes scatterer,close quotes and the epithermal neutron beam. The Monte Carlo code, MCNP, was used to compute the total effective dose equivalent rates at specific points of interest outside of the treatment room. A conservative occupational effective dose rate limit of 0.01 mSv h -1 was the guideline for this study. Conservative Monte Carlo calculations show that constructing the treatment room walls with 1.5 m of ordinary concrete, 1.2 m of barytes concrete, 1.0 m of ordinary concrete preceded by 10 cm of 5% boron-polyethylene, or 0.8 m of barytes concrete preceded by 10 cm of 5% boron-polyethylene will adequately protect facility personnel. 20 refs., 8 figs., 2 tabs

The evaluation the magnitude radiation exposure dose rate in digital radiography room design

Science.gov (United States)

Dwiyanto, Agung; Setia Budi, Wahyu; Hardiman, Gagoek

2017-12-01

This study discusses the dose rate in digital radiography room, buit according to meet the provisions of KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation of BAPETEN No. 8 / 2011. The provisions primary concern of radiation safety, not comfort, by considering the space design. There are five aspects to consider in designing the space: functionality, comfort, security, movement activities and aesthetics. However provisions only met three aspects of the design, which are a function, security and movement activity. Therefore, it is necessary to evaluate digital radiography room in terms of its ability to control external radiation exposure to be safe and comfortable The dose rate is measured by the range of primary and secondary radiation in the observation points by using Surveymeter. All data are obtained by the preliminary survey prior to the study. Furthermore, the review of digital radiography room is done based on architectural design theory. The dose rate for recommended improvement room is recalculated using the same method as the actual room with the help of computer modeling. The result of dose rate calculation at the inner and outer part of digital radiography observation room shows that in-room dose for a week at each measuring point exceeds the allowable dose limit both for staff and public. During a week of observation, the outdoor dose at some measuring points exceeds the dose limit set by the KEMENKES No.1014 / Menkes / SK / XI / 2008 and Regulation BEPETEN No 8/2011. Meanwhile, the result of dose rate calculation in the inner and outer part of the improved digital radiography room can meet the applicable regulations better.

Comparison between steel and lead shieldings for radiotherapy rooms regarding neutron doses to patients

International Nuclear Information System (INIS)

Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G.

2015-01-01

The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H *(10) n , within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5 x 5 cm 2 , 10 x 10 cm 2 , 20 x 20 cm 2 , 30 x 30 cm 2 and 40 x 40 cm 2 openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H *(10) n at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation. (author)

Public Dose Assessment Modeling from Skyshine by Proton Accelerator

Energy Technology Data Exchange (ETDEWEB)

Mwambinga, S. A. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Yoo, S. J. [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2013-10-15

In this paper, the skyshine dose by proton accelerator (230 MeV) has been evaluated. The amount of dose by skyshine is related to some influence factors which are emission angle (Height wall), the thickness of ceiling and distance from source to receptor (Human body). Empirical formula is made by using MCNPX code results. It can easily calculate and assess dose from skyshine by proton accelerator. The skyshine doses are calculated with MCNPX code and DCFs in ICRP 116. Thereafter, we made empirical formula which can calculate dose easily and be compared with the results of MCNPX. The maximum exposure point by skyshine is about 5 ∼ 10 m from source. Therefore, the licensee who wants to operate the proton accelerator must keep the appropriate distance from accelerator and set the fence to restrict the approach by the public. And, exposure doses by accelerator depend on operating time and proton beam intensities. Eq. (6) suggested in this study is just considered for mono energy proton accelerator. Therefore, it is necessary to expand the dose calculation to diverse proton energies. Radiations like neutron and photon generated by high energy proton accelerators over 10 MeV, are important exposure sources to be monitored to radiation workers and the public members near the facility. At that case, one of the exposure pathways to the public who are located in near the facility is skyshine. Neutrons and photons can be scattered by the atmosphere near the facility and exposed to public as scattered dose. All of the facilities using high energy radiation and NDI (Non-Destructive Inspection) which is tested at open field, skyshine dose must be taken into consideration. Skyshine dose is not related to the wall thickness of radiation shielding directly.

Deuteron and neutron induced activation in the Eveda accelerator materials: implications for the accelerator maintenance

Energy Technology Data Exchange (ETDEWEB)

Garcia, M.; Sanz, J.; Garcia, N.; Cabellos, O. [Madrid Univ. Politecnica, C/ Jose Gutierrez Abascal, lnstituto de Fusion Nuclear (Spain); Sauvan, R. [Universidad Nacional de Educacion a Distancia (UNED), Madrid (Spain); Moreno, C.; Sedano, L.A. [CIEMAT-Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, Association Euratom-CIEMAT, Madrid (Spain)

2007-07-01

Full text of publication follows: The IFMIF (International Fusion Materials Irradiation Facility) is an accelerator-based DLi neutron source designed to test fusion reactor candidate materials for high fluence neutrons. Before deciding IFMIF construction, an engineering design and associated experimental data acquisition, defined as EVEDA, has been proposed. Along the EVEDA accelerator, deuteron beam losses collide with the accelerator materials, producing activation and consequent radiations responsible of dose. Calculation of the dose rates in the EVEDA accelerator room is necessary in order to analyze the feasibility for manual maintenance. Dose rates due to the activation produced by the deuteron beam losses interaction with the accelerator materials, will be calculated with the ACAB activation code, using EAF2007 library for deuteron activation cross-sections. Also, dose rates from the activation induced by the neutron source produced by the interaction of deuteron beam losses with the accelerator materials and the deuterium implanted in the structural lattice, will be calculated with the SRIM2006, TMAP7, DROSG2000/NEUYIE, MCNPX and ACAB codes. All calculations will be done for the EVEDA accelerator with the room temperature DTL structure, which is based on copper cavities for the DTL. Some calculations will be done for the superconducting DTL structure, based on niobium cavities for the DTL working at cryogenic temperature. Final analysis will show the dominant mechanisms and major radionuclides contributing to the surface dose rates. (authors)

Comparison between steel and lead shieldings for radiotherapy rooms regarding neutron doses to patients

Energy Technology Data Exchange (ETDEWEB)

Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G., E-mail: eng.cavaliere@gmail.com, E-mail: ggrprojetos@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Silva, A.X., E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H *(10){sub n}, within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5 x 5 cm{sup 2}, 10 x 10 cm{sup 2}, 20 x 20 cm{sup 2}, 30 x 30 cm{sup 2} and 40 x 40 cm{sup 2} openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H *(10){sub n} at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation. (author)

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)

Personnel hazards from medical electron accelerator photoneutrons

International Nuclear Information System (INIS)

McCall, R.C.; Jenkins, T.M.; Shore, R.A.; LaRiviere, P.D.

1979-12-01

For medical accelerators, neutron penetration through the room entry door is the major personnel hazard. Most therapy accelerator rooms are designed with at least a rudimentary maze to avoid the use of massive doors. Often, however, the maze may be similar to those shown in scale outline drawings of some medical electron accelerator rooms where the authors have made neutron measurements outside the doors which were of different thicknesses and compositions. The results are tabulated. It should be noted that there can be significant dose equivalents (H) at the door when a maze is inadequate, and that all three components - fast neutron, thermal neutron, and neutron capture γ rays - can be equally important

Research on cw electron accelerators using room-temperature rf structures: Annual report

International Nuclear Information System (INIS)

1986-01-01

This joint NBS-Los Alamos project of ''Research on CW Electron Accelerators Using Room-Temperature RF Structures'' began seven years ago with the goal of developing a technology base for cw electron accelerators. In this report we describe our progress during FY 1986 and present our plans for completion of the project. First, however, it is appropriate to review the past contributions of the project, describe its status, and indicate its future benefits

Dose rate in the reactor room and environment during maintenance in fusion reactors

International Nuclear Information System (INIS)

Maki, Koichi; Satoh, Satoshi; Takatsu, Hideyuki; Seki, Yasushi

1995-01-01

According to the International Thermonuclear Experimental Reactor (ITER) conceptual design activity, after reactor shutdown, damaged segments are pulled up from the reactor and hung from the reactor room ceiling by a remote handling device. The dose rate in the reactor room and the environment is estimated for this situation, and the following results are obtained. First, the dose rate in the room is > 10 8 μSv/h. Since this dose rate is 10 7 times greater than the biological radiation shielding design limit of 25 μSv/h, workers cannot enter the room. Second, lenses and optical fiber composed of glass that is radiation resistant up to 10 6 Gy would be damaged after <100 h near the segment, and devices using semiconductors could not work after several hours or so in the aforementioned dose-rate conditions. Third, during suspension of one blanket segment from the ceiling, the dose rate in the site boundary can be reduced by one order by a 23-cm-thicker reactor building roof. To reduce dose rate in public exposure to a value that is less than one-tenth of the public exposure radiation shielding design limit of 100 μSv/yr, the distance of the site boundary from the reactor must be greater than 200 m for a reactor building with a 160-cm-thick concrete roof. 9 refs., 6 figs., 2 tabs

Dose to radiation therapists from activation at high-energy accelerators used for conventional and intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Rawlinson, J. Alan; Islam, Mohammad K.; Galbraith, Duncan M.

2002-01-01

The increased beam-on times which characterize intensity-modulated radiation therapy (IMRT) could lead to an increase in the dose received by radiation therapists due to induced activity. To examine this, gamma ray spectrometry was used to identify the major isotopes responsible for activation at a representative location in the treatment room of an 18 MV accelerator (Varian Clinac 21EX). These were found to be 28 Al, 56 Mn, and 24 Na. The decay of the dose rate measured at this location following irradiation was analyzed in terms of the known half-lives to yield saturation dose rates of 9.6, 12.4, and 6.2 μSv/h, respectively. A formalism was developed to estimate activation dose (μSv/week) due to successive patient irradiation cycles, characterized by the number of 18 MV fractions per week, F, the number of MU per fraction, M, the in-room time between fractions, t d (min), and the treatment delivery time t r ' (min). The results are represented by the sum of two formulas, one for the dose from 28 Al≅1.8x10 -3 F M (1-e -0.3t r ' )/t r ' and one for the dose from the other isotopes ≅1.1x10 -6 F 1.7 Mt d . For conventional therapy doses are about 60 μ Sv/week for an 18 MV workload of 60 000 MU/week. Irradiation for QA purposes can significantly increase the dose. For IMRT as currently practiced, lengthy treatment delivery times limit the number of fractions that can be delivered per week and hence limit the dose to values similar to those in conventional therapy. However for an IMRT regime designed to maximize patient throughput, doses up to 330 μSv/week could be expected. To reduce dose it is recommended that IMRT treatments should be delivered at energies lower than 18 MV, that in multienergy IMRT, high-energy treatments should be scheduled in the latter part of the day, and that equipment manufacturers should strive to minimize activation in the design of high-energy accelerators

A study on optimization of photoneutron shielding in a medical accelerator room by using Monte Carlo simulation

International Nuclear Information System (INIS)

Kim, Yong Nam; Jeong, Kyoungkeun; Kim, Joo Young; Lee, Chang Geol; Seong, Jinsil; Choi, Sang Hyun; Kim, Chan Hyeong

2008-01-01

Medical linear accelerators operating above 10 MV require door shielding for neutrons in addition to photons. A criterion for choice of optimal configuration of lamination of BPE (Borated Polyethylene) and lead is not clear. Moreover, optimal configuration cannot be determined by the conventional method using an analytical formula and simple measurement. This study performs Monte Carlo simulation of radiation field in a commercial LINAC room with 15 MV X-ray sources. Considering two configuration of lamination such as 'lead-BPE' and 'lead-BPE-lead', dose equivalents are calculated by using the MCNPX code and comparative analyses are performed with each other. The obtained results show that there is no significant difference in neuron shielding between both configurations, whereas lead-BPE-lead is more effective for photon shielding. It is also noted that the absolute values of neutron doses are much greater than that of photon doses outside as well as inside the door, by three orders of magnitude. As a conclusion, the laminating of lead-BPE is suggested as the optimal configuration from the viewpoint of simplicity in fabrication and handling, even though it has no significant difference from lead-BPE-lead in terms of total dose equivalent. (author)

Practical high-density shielding materials for medical linear accelerator rooms

International Nuclear Information System (INIS)

Barish, R.J.

1990-01-01

High-energy linear accelerators are replacing lower energy units in radiation therapy centers. Radiation protection requirements necessitate expensive reconstruction of existing treatment rooms to accommodate these new machines. We describe two shielding materials: one made by embedding small pieces of scrap steel in cement, and the other made with cast iron in cement. Both materials produce high-density barriers at low cost using standard construction methods

Neutrons from medical electron accelerators

International Nuclear Information System (INIS)

Swanson, W.P.; McCall, R.C.

1979-06-01

The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. Measured data obtained at a variety of accelerator installations are presented and compared with these calculations. It is found that the high-Z materials within the treatment head do not significantly alter the neutron fluence, but do substantially reduce the average energy of the transmitted spectrum. Reflected neutrons from the concrete treatment room contribute to the neutron fluence, but not substantially to the patient integral dose, because of a further reduction in average energy. Absolute depth-dose distributions for realistic neutron spectra are calculated, and a rapid falloff with depth is found

The use of steel and lead shieldings in radiotherapy rooms and its comparison with respect to neutrons doses at patients

International Nuclear Information System (INIS)

Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G.; Santos, R.F.G.

2015-01-01

The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H*(10) n , within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5x5cm 2 , 10x10cm 2 , 20x20cm 2 , 30x30cm 2 and 40x40cm 2 openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H*(10) n at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation.

A dose-per-pulse monitor for a dual-mode medical accelerator

International Nuclear Information System (INIS)

Galbraith, D.M.; Martell, E.S.; Fueurstake, T.; Norrlinger, B.; Schwendener, H.; Rawlinson, J.A.

1990-01-01

On a radiotherapy accelerator, the dose monitoring system is the last level of protection between the patient and the extremely high dose rate which all accelerators are capable of producing. The risk of losing this level of protection is substantially reduced if two or more dose monitoring systems are used which are mechanically and electrically independent in design. This paper describes the installation of an independent radiation monitor in a dual-mode, computer-controlled accelerator with a moveable monitor chamber. The added device is fixed in the beam path, is capable of monitoring each beam pulse, and is capable of terminating irradiation within the pulse repetition period if any measured pulse is unacceptably high

Pre-installation empirical testing of room shielding for high dose rate remote afterloaders

International Nuclear Information System (INIS)

Klein, E.E.; Grigsby, P.W.; Williamson, J.F.; Meigooni, A.S.

1993-01-01

PURPOSE: Many facilities are acquiring high dose rate remote afterloading units. It is economical that these units be placed in existing shielded teletherapy rooms. Scatter-radiation barriers marginally protect uncontrolled areas from a high dose rate source especially in a room that houses a non-dynamic Cobalt-60 unit. In addition the exact thickness and material composition of the barriers are unknown and therefore, a calculation technique may give misleading results. Also, it would be impossible to evaluate an entire wall barrier by taking isolated core samples in order to assist in the calculations. A quick and inexpensive measurement of dose equivalent using a rented high activity 192Ir source evaluates the barriers and locates shielding deficiencies. METHODS AND MATERIALS: We performed transmission calculations for primary and scattered radiation based on National Council on Radiation Protection and Measurements Reports 49 and 51, respectively. We then rented a high activity 21.7 Ci (8.03 x 10(11) Bq) Ir-192 source to assess our existing teletherapy room shielding for adequacy and voids. This source was placed at the proposed location for clinical high dose rate treatment and measurements were performed. RESULTS: No deficiencies were found in controlled areas surrounding the room, but large differences were found between the calculated and measured values. Our survey located a region in the uncontrolled area above the room requiring augmented shielding which was not predicted by the calculations. A canopy shield was designed to potentially augment the shielding in the ceiling direction. CONCLUSION: Pre-installation testing by measurement is an invaluable method for locating shielding deficiencies and avoiding unnecessary enhancement of shielding particularly when there is lack of information of the inherent shielding

Neutron dose measurements with the GSI ball at high energy accelerators

International Nuclear Information System (INIS)

Fehrenbacher, G.; Gutermuth, F.; Radon, T.; Kozlova, E.

2005-01-01

Full text: At high energy particle accelerators the production of neutron radiation dominates radiation protection. For the radiation survey at accelerators there is a need for reliable detection systems (passive radiation monitors), which can measure the dose for a wide range of neutron energies independently on the beam pulse structure of the produced radiation. In this work a passive neutron dosemeter for the measurement of the ambient dose equivalent is presented. The dosemeter is suitable for measurements of the emerging neutron radiation at accelerators for the whole energy range up to about 10 GeV. The dosemeter consists of a polyethylene sphere, TL elements (pairs of TLD600/700) and an additional lead layer (PE/Pb) in neutron fields at high energy accelerators is investigated in this work. Results of dose measurements which were performed in realistic neutron fields at the high energy accelerator SPS at CERN (CERF facility) and in Cave A at the heavy ion synchrotron SIS at GSI are presented. The results of these measurements are compared with the expected dose values from the neutron spectra determined for the measurement positions at CERF and in Cave A (FLUKA) and with the dosemeter response derived by the calculated response functions (FLUKA) folded with the neutron spectra. The comparisons show that the additional lead layer in the PE/Pb-sphere improves significantly the response of the dosemeter. The response of the PE/Pb-sphere is 40 to 50 % higher at CERF and Cave A in comparison to the bare PE-sphere. At CERF the dose values of the PE/Pb-sphere is about 25 % lower than the expected dose value, whilst for Cave A, a rather good agreement was found (2 % deviation). (author)

Method for pulse to pulse dose reproducibility applied to electron linear accelerators

International Nuclear Information System (INIS)

Ighigeanu, D.; Martin, D.; Oproiu, C.; Cirstea, E.; Craciun, G.

2002-01-01

An original method for obtaining programmed beam single shots and pulse trains with programmed pulse number, pulse repetition frequency, pulse duration and pulse dose is presented. It is particularly useful for automatic control of absorbed dose rate level, irradiation process control as well as in pulse radiolysis studies, single pulse dose measurement or for research experiments where pulse-to-pulse dose reproducibility is required. This method is applied to the electron linear accelerators, ALIN-10 of 6.23 MeV and 82 W and ALID-7, of 5.5 MeV and 670 W, built in NILPRP. In order to implement this method, the accelerator triggering system (ATS) consists of two branches: the gun branch and the magnetron branch. ATS, which synchronizes all the system units, delivers trigger pulses at a programmed repetition rate (up to 250 pulses/s) to the gun (80 kV, 10 A and 4 ms) and magnetron (45 kV, 100 A, and 4 ms).The accelerated electron beam existence is determined by the electron gun and magnetron pulses overlapping. The method consists in controlling the overlapping of pulses in order to deliver the beam in the desired sequence. This control is implemented by a discrete pulse position modulation of gun and/or magnetron pulses. The instabilities of the gun and magnetron transient regimes are avoided by operating the accelerator with no accelerated beam for a certain time. At the operator 'beam start' command, the ATS controls electron gun and magnetron pulses overlapping and the linac beam is generated. The pulse-to-pulse absorbed dose variation is thus considerably reduced. Programmed absorbed dose, irradiation time, beam pulse number or other external events may interrupt the coincidence between the gun and magnetron pulses. Slow absorbed dose variation is compensated by the control of the pulse duration and repetition frequency. Two methods are reported in the electron linear accelerators' development for obtaining the pulse to pulse dose reproducibility: the method

High-dose amrinone is required to accelerate rewarming from deliberate mild intraoperative hypothermia for neurosurgical procedures.

Science.gov (United States)

Inoue, Satoki; Kawaguchi, Masahiko; Sakamoto, Takanori; Kitaguchi, Katsuyasu; Furuya, Hitoshi; Sakaki, Toshisuke

2002-07-01

Since the time available to provide the cooling and rewarming is limited during deliberate mild hypothermia, the technique to accelerate the cooling and rewarming rate of core temperature has been studied. Amrinone has been reported to accelerate the cooling rate but not the rewarming rate of core temperature during deliberate mild hypothermia. The failure of amrinone effect on the rewarming rate might be due to an insufficient dose of amrinone during hypothermic conditions. The authors therefore tested whether higher doses of amrinone can accelerate the rewarming rate of core temperature during deliberate mild hypothermia for neurosurgery. After institutional approval and informed consent, 30 patients were randomly assigned to one of three groups. Patients in the control group (n = 10) did not receive amrinone; patients in the AMR 15 group (n = 10) received 15 microg x kg(-1) x min(-1) amrinone with a 1.0-mg/kg loading dose of amrinone at the beginning of cooling; and patients in the ReAMR group (n = 10) received 5 microg x kg(-1) x min(-1) amrinone with 1.0-mg/kg loading and reloading doses of amrinone at the beginning of cooling and rewarming, respectively. Administration of amrinone was started just after the induction of cooling and continued until the end of anesthesia. Anesthesia was maintained with nitrous oxide in oxygen, propofol, and fentanyl. After induction of anesthesia, patients were cooled, and tympanic membrane temperature was maintained at 34.5 degrees C. After completion of the main surgical procedures, patients were actively rewarmed and extubated in the operating room. The cooling and rewarming rates of core temperature were both significantly faster in both amrinone groups than in the control group. During the cooling and rewarming periods, forearm minus fingertip temperature gradient was significantly smaller in both amrinone groups than in the control group. During the rewarming period, heart rate and mean arterial pressure in the AMR 15

Dose-dependent optically stimulated luminescence of synthetic quartz at room temperature

International Nuclear Information System (INIS)

Kale, Y.D.; Gandhi, Y.H.; Gartia, R.K.

2008-01-01

Physical conditions such as annealing temperature, duration of annealing, ionizing radiation, etc., play a significant role in the applications of optically stimulated luminescence (OSL) dating as well as OSL dosimetry. Many efforts are made to understand the effect of these physical parameters on quartz specimens owing to its use in such applications. Such factors induce changes in OSL decay pattern. The definite correlation between color centers and luminescence sensitivity can be established on account of such pre-treatments to the specimen. The purpose of present investigations is to study the effect of ionizing radiation under identical physical conditions on OSL properties measured at room temperature. The shapes of decay curve and dose-response data are considered for this purpose. This study can reveal the changes in color centers in response to the pre-conditions to the specimen. It was found that the OSL decay remains slow and OSL properties change systematically with the rise in beta dose up to a critical dose; however, it changes the pattern when the beta exposure to the specimen was increased higher than the critical dose. This critical dose was found to be different for different temperature of annealing. The shape of decay curve up to the critical dose was also studied by considering the difference of OSL intensities between two successive durations from the observed OSL decay data. The results are explained based on the changes in available shallow traps during OSL measurement at room temperature with changes in pre-conditions to the specimens. The results also have been confirmed with the corresponding changes in ESR signals

The radiation dose to accompanying nurses, relatives and other patients in a nuclear medicine department waiting room

Energy Technology Data Exchange (ETDEWEB)

Harding, L K; Harding, N J; Warren, H; Mills, A; Thomson, W H [Dudley Road Hospital, Birmingham (UK)

1990-01-01

The radiation dose to accompanying nurses, relatives and other patients in a nuclear medicine department waiting room was assessed at 5 min intervals by observing the seating arrangement. The total radiation dose to each person was calculated, using fixed values of dose rate per 100 MBq activity for radionuclides, and applying the inverse square law. Radioactive decay and attenuation effects due to intervening persons were also taken into account. The median radiation doses to accompanying nurses, relatives and other patients were 2.3, 2.0 and 0.2 {mu}Sv with maximum values of 17, 33 and 5 {mu}Sv respectively. In all cases, the radiation dose received by patients was less than 0.2% of the radiation dose resulting from their own investigation. Also, the maximum radiation dose received by an accompanying norse or friend was less than 1% of their appropriate annual dose limit. Similar values were obtained with calculations based on a 15 min time interval. The radiation doses received by those in a nuclear medicine department waiting room are small, and separate waiting room facilities for radioactive patients are unnecessary. (author).

Calorimetry for absorbed dose measurement at 1-4 MeV electron accelerators

International Nuclear Information System (INIS)

Miller, A.

2000-01-01

Calorimeters are used for dose measurement, calibration and intercomparisons at industrial electron accelerators, and their use at 10 MeV electron accelerators is well documented. The work under this research agreement concerns development of calorimeters for use at electron accelerators with energies in the range of 2-4 MeV. The dose range of the calorimeters is 3-40 kGy, and their temperature stability after irradiation was found to be sufficient for practical use in an industrial environment. Measurement uncertainties were determined to be 5% at k = 2. (author)

Effects of activity inhomogeneities in walls on the external gamma doses in rooms

Energy Technology Data Exchange (ETDEWEB)

Feher, I; Andrasi, A; Koblinger, L; Zombori, P; Szabo, P P [Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics

1984-01-01

The effects of activity inhomogeneities in the walls of a room on the free-in-air and spherical phantom doses are investigated. Calculations and measurements are carried out in a room where the ratios of the activity concentrations in the upper layer of the ceiling and floor are as large as 20 and 6, for the Ra and Th chains, respectively.

Neutron radiation from medical electron accelerators

International Nuclear Information System (INIS)

McCall, R.C.

1983-01-01

A method is described using simple gold foils and relatively inexpensive moderators to measure neutron fluences, both fast nd thermal, which then can be converted to dose equivalent using a few simple formulas. The method is sensitive, easy to calibrate, and should work at most accelerators regardless of energy or room geometry

A neutron survey of a 25 MV x-ray clinical linac treatment room

International Nuclear Information System (INIS)

Price, Kenneth W.; Holeman, George R.; Nath, Ravinder

1978-01-01

Neutron production in high energy x-ray radiotherapy machines results in unnecessary dose to patients and has been of recent interest to private and Federal agencies. An activation technique has been used to measure fast and thermal neutron fluxes in the high energy x-ray beam, and at radial distances of 1 and 2 meters from the beam axis of the 25 MV Sagittaire Linear Accelerator located at the Yale-New Haven Hospital's Cancer Therapy Center. Phosphorous pentoxide activation detectors were used to monitor the thermal flux and the fast neutron flux above 0.7 MeV neutron energy. Unlike other techniques for measuring neutrons, this detector has been shown to be insensitive to high energy photon interference at the photon dose rates present in the beam. Neutron spectra at various distances from the accelerator target were computed for the treatment room geometry using the Morse Monte Carlo Code (R.C. McCall, SLAC, Personal Communication). Normalization of these spectra provided the means by which the activation products measured in the phosphorous were converted to fast neutron fluxes. Dose equivalent conversion factors were applied to each energy of the calculated neutron spectra and integrated, resulting in fast neutron flux to dose equivalent conversion factors at various locations in the treatment room. Fast neutron dose equivalent was found to maximize in the photon beam, (0.005 - .007 neutron Rem/photon Rad) and decrease with distance thereafter. Thermal neutron dose equivalent was found to be essentially constant through- out the treatment room (∼ 3.35x10 -5 neutron Rem/ photon Rad). (author)

EB dose calibration for 10 MeV linear accelerator

International Nuclear Information System (INIS)

Owczarczyk, H.B.; Migdal, W.; Stachowicz, W.

2002-01-01

The National Institute of Standards and Technology Gaitherburg USA has done in co-operation with INCT Warsaw the EPR dose measurements for two INCT 60 Co irradiators using l-alanine standard pellets as dosimeter medium. In the study the comparative EPR measurements of doses up to 40 kGy have been done using l-alanine powder with 60 Co source (reference to NIST standard) and EB linear accelerator, respectively. On the basis of this comparative study 5% correction factor for EB dose measurements has been adapted in the INCT Experimental Plant for Food Irradiation traceable to the dose estimations done with the Risoe calorimetric system

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...

Initial investigations of dose distribution patterns for an industrial electron accelerator

International Nuclear Information System (INIS)

Ehlermann, D.A.E.

1994-01-01

A newly developed accelerator for electrons in the dose range of up 10 mev at 10 kw performance replaces a similar type of accelerator that has been in use during the past 25 years. It is characterized by some decisive technical changes. The ray, rather than moving from one point to the next, is now distributed over the merchandise for the duration of an impulse. In the direction of conveyance, irradiation is carried out on successive fields as was done formerly. As the duration of impulse is no longer than 12 μs, some problems arose in respect of operation and measuring techniques: the time distribution of microwave energy or rays emitted during the individual impulses has a bearing on the dose distribution pattern at a right angle to the direction of transport in both the superficial and deep layers of the merchandise. Some of the initial measuring results are represented here. The accelerator's operational parameters were then so adjusted that a largely homogeneous dose distribution was achieved throughout. (orig.) [de

Calculation of dose equivalents for photon skyshine production; Calculo da dose equivalente para fotons decorrente da producao de skyshine

Energy Technology Data Exchange (ETDEWEB)

Frota, Marco A.; Kelecom, Alphonse [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Biologia Geral. Lab. de Radiobiologia e Radiometria (LARARA)]. E-mail: egbakel@vm.uff.br

2005-07-01

Some radiation facilities are designed with little shielding in the ceiling above the accelerator. A problem may then arise as a result of the radiation scattered by the atmosphere to points at ground level outside the treatment room. Stray radiation of this type is referred to as skyshine, and the National Council on Radiation Protection and Measurements Report No. 51 (NCRP 1977) gives methods for the calculation of skyshine for accelerator facilities. McGinley (1993) has compared skyshine measurements made at an 18 MeV medical accelerator facility with values calculated using the techniques presented in NCRP Report No. 51. Measurements were made of the photon levels outside a treatment room housing a Varian 2100 deg C. The roof above the accelerator was designed for weather protection only and offered little shielding for the primary beam and scattered radiation. The distance from the treatment room floor to the roof was 4.27 m, and the primary walls were constructed of concrete 2.0 m thick.The secondary walls were fabricated of concrete 0.99 m thick. The results for the photon skyshine rate dose as a function of distance from the isocenter using Monte Carlo code, are compared with those in NCRP publication 74 and measured obtained. The photon skyshine dose rates simulated for real clinic spectra transmitted through roof range from 4.7 to 14.6 nSv.s{sup -1}. (author)

Monte Carlo simulation to study the doses in an accelerator BNCT treatment

International Nuclear Information System (INIS)

Burlon, Alejandro A.; Valda, Alejandro A.; Somacal, Hector R.; Kreiner, Andres J.; Minsky, Daniel M.

2003-01-01

In this work the 7 Li(p, n) 7 Be reaction has been studied as a neutron source for accelerator-based BNCT (Boron Neutron Capture Therapy). In order to optimize the design of the neutron production target and the beam shaping assembly, extensive MCNP simulations have been performed. These simulations include a thick Li metal target, a whole-body phantom, a moderator-reflector assembly (Al/AlF 3 as moderator and graphite as reflector) and the treatment room. The doses were evaluated for two proton bombarding energies of 1.92 MeV (near to the threshold of the reaction) and 2.3 MeV (near to the resonance of the reaction) and for three Al/ALF 3 moderator thicknesses (18, 26 and 34 cm). To assess the doses, a comparison using a Tumor Control Probability (TCP) model was done. In a second instance, the effect of the specific skin radiosensitivity (an RBE of 2.5 for the 10 B(n,α) 7 Li reaction) and a 10 B uptake of 17 ppm was considered for the scalp. Finally, the simulations show the advantage of irradiating with near-resonance-energy protons (2.3 MeV) because of the high neutron yield at this energy, leading to the lowest treatment times. Moreover, the 26 cm Al/AlF 3 moderator has shown the best performance among the studied cases. (author)

An absolute dose determination of helical tomotherapy accelerator, TomoTherapy High-Art II

International Nuclear Information System (INIS)

Bailat, Claude J.; Buchillier, Thierry; Pachoud, Marc; Moeckli, Raphaeel; Bochud, Francois O.

2009-01-01

Purpose: A helical tomotherapy accelerator presents a dosimetric challenge because, to this day, there is no internationally accepted protocol for the determination of the absolute dose. Because of this reality, we investigated the different alternatives for characterizing and measuring the absolute dose of such an accelerator. We tested several dosimetric techniques with various metrological traceabilities as well as using a number of phantoms in static and helical modes. Methods: Firstly, the relationship between the reading of ionization chambers and the absorbed dose is dependent on the beam quality value of the photon beam. For high energy photons, the beam quality is specified by the tissue phantom ratio (TPR 20,10 ) and it is therefore necessary to know the TPR 20,10 to calculate the dose delivered by a given accelerator. This parameter is obtained through the ratio of the absorbed dose at 20 and 10 cm depths in water and was measured in the particular conditions of the tomotherapy accelerator. Afterward, measurements were performed using the ionization chamber (model A1SL) delivered as a reference instrument by the vendor. This chamber is traceable in absorbed dose to water in a Co-60 beam to a water calorimeter of the American metrology institute (NIST). Similarly, in Switzerland, each radiotherapy department is directly traceable to the Swiss metrology institute (METAS) in absorbed dose to water based on a water calorimeter. For our research, this traceability was obtained by using an ionization chamber traceable to METAS (model NE 2611A), which is the secondary standard of our institute. Furthermore, in order to have another fully independent measurement method, we determined the dose using alanine dosimeters provided by and traceable to the British metrology institute (NPL); they are calibrated in absorbed dose to water using a graphite calorimeter. And finally, we wanted to take into account the type of chamber routinely used in clinical practice and

Accelerated Irradiations for High Dose Microstructures in Fast Reactor Alloys

Energy Technology Data Exchange (ETDEWEB)

Jiao, Zhijie [Univ. of Michigan, Ann Arbor, MI (United States)

2017-03-31

The objective of this project is to determine the extent to which high dose rate, self-ion irradiation can be used as an accelerated irradiation tool to understand microstructure evolution at high doses and temperatures relevant to advanced fast reactors. We will accomplish the goal by evaluating phase stability and swelling of F-M alloys relevant to SFR systems at very high dose by combining experiment and modeling in an effort to obtain a quantitative description of the processes at high and low damage rates.

Evaluation of accelerated test parameters for CMOS IC total dose hardness prediction

International Nuclear Information System (INIS)

Sogoyan, A.V.; Nikiforov, A.Y.; Chumakov, A.I.

1999-01-01

The approach to accelerated test parameters evaluation is presented in order to predict CMOS IC total dose behavior in variable dose-rate environment. The technique is based on the analytical model of MOSFET parameters total dose degradation. The simple way to estimate model parameter is proposed using IC's input-output MOSFET radiation test results. (authors)

Shielding calculation for treatment rooms of high energy linear accelerator

International Nuclear Information System (INIS)

Elleithy, M.A.

2006-01-01

A review of German Institute of Standardization (DIN) scheme of the shielding calculation and the essential data required has been done for X-rays and electron beam in the energy range from 1 MeV to 50 MeV. Shielding calculation was done for primary and secondary radiations generated during X-ray operation of Linac. In addition, shielding was done against X-rays generated (Bremsstrahlung) by useful electron beams. The calculations also covered the neutrons generated from the interactions of useful X-rays (at energies above 8 MeV) with the surrounding. The present application involved the computation of shielding against the double scattered components of X-rays and neutrons in the maze area and the thickness of the paraffin wax of the room door. A new developed computer program was designed to assist shielding thickness calculations for a new Linac installation or in replacing an existing machine. The program used a combination of published tables and figures in computing the shielding thickness at different locations for all possible radiation situations. The DIN published data of 40 MeV accelerator room was compared with the program calculations. It was found that there is good agreement between both calculations. The developed program improved the accuracy and speed of calculation

Accelerated color development of irradiated radiochromic dye films

International Nuclear Information System (INIS)

Chappas, W.J.

1981-01-01

The radiochromic dye films developed by Chalkley and McLaughlin are quickly becoming one of the principal methods for secondary dosimetry. Their useful dose and dose rate ranges, long-term color stability, small and flexible size, and ease of reading make them ideal for spatial dose distribution measurements in the complex targets often encountered in industry. At room temperature, however, their response is slow, requiring several hours after irradiation for full color development. This work examines the effect of humidity on the film's time response and describes a method for accelerating the film's color development. By keeping the film in a controlled humidity environment or through a simple heating technique, the film can be read in minutes instead of hours after irradiation. The results are shown to be identical to those of films stored for 24 hours at room temperature

Development of a computational model for the calculation of neutron dose equivalent in laminated primary barriers of radiotherapy rooms

International Nuclear Information System (INIS)

Rezende, Gabriel Fonseca da Silva

2015-01-01

Many radiotherapy centers acquire 15 and 18 MV linear accelerators to perform more effective treatments for deep tumors. However, the acquisition of these equipment must be accompanied by an additional care in shielding planning of the rooms that will house them. In cases where space is restricted, it is common to find primary barriers made of concrete and metal. The drawback of this type of barrier is the photoneutron emission when high energy photons (e.g. 15 and 18 MV spectra) interact with the metallic material of the barrier. The emission of these particles constitutes a problem of radiation protection inside and outside of radiotherapy rooms, which should be properly assessed. A recent work has shown that the current model underestimate the dose of neutrons outside the treatment rooms. In this work, a computational model for the aforementioned problem was created from Monte Carlo Simulations and Artificial Intelligence. The developed model was composed by three neural networks, each being formed of a pair of material and spectrum: Pb18, Pb15 and Fe18. In a direct comparison with the McGinley method, the Pb18 network exhibited the best responses for approximately 78% of the cases tested; the Pb15 network showed better results for 100% of the tested cases, while the Fe18 network produced better answers to 94% of the tested cases. Thus, the computational model composed by the three networks has shown more consistent results than McGinley method. (author)

Application of the personnel photographic monitoring method to determine equivalent radiation dose beyond proton accelerator shielding

International Nuclear Information System (INIS)

Gel'fand, E.K.; Komochkov, M.M.; Man'ko, B.V.; Salatskaya, M.I.; Sychev, B.S.

1980-01-01

Calculations of regularities to form radiation dose beyond proton accelerator shielding are carried out. Numerical data on photographic monitoring dosemeter in radiation fields investigated are obtained. It was shown how to determine the total equivalent dose of radiation fields beyond proton accelerator shielding by means of the photographic monitoring method by introduction into the procedure of considering nuclear emulsions of division of particle tracks into the black and grey ones. A comparison of experimental and calculational data has shown the applicability of the used calculation method for modelling dose radiation characteristics beyond proton accelerator shielding [ru

An MCNP-based model for the evaluation of the photoneutron dose in high energy medical electron accelerators.

Science.gov (United States)

Carinou, Eleutheria; Stamatelatos, Ion Evangelos; Kamenopoulou, Vassiliki; Georgolopoulou, Paraskevi; Sandilos, Panayotis

The development of a computational model for the treatment head of a medical electron accelerator (Elekta/Philips SL-18) by the Monte Carlo code mcnp-4C2 is discussed. The model includes the major components of the accelerator head and a pmma phantom representing the patient body. Calculations were performed for a 14 MeV electron beam impinging on the accelerator target and a 10 cmx10 cm beam area at the isocentre. The model was used in order to predict the neutron ambient dose equivalent at the isocentre level and moreover the neutron absorbed dose distribution within the phantom. Calculations were validated against experimental measurements performed by gold foil activation detectors. The results of this study indicated that the equivalent dose at tissues or organs adjacent to the treatment field due to photoneutrons could be up to 10% of the total peripheral dose, for the specific accelerator characteristics examined. Therefore, photoneutrons should be taken into account when accurate dose calculations are required to sensitive tissues that are adjacent to the therapeutic X-ray beam. The method described can be extended to other accelerators and collimation configurations as well, upon specification of treatment head component dimensions, composition and nominal accelerating potential.

On isocentre adjustment and quality control in linear accelerator based radiosurgery with circular collimators and room lasers

Energy Technology Data Exchange (ETDEWEB)

Treuer, H. [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany). E-mail: h.treuer at uni-koeln.de; Hoevels, M.; Luyken, K.; Gierich, A.; Sturm, V. [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Kocher, M.; Mueller, R.-P. [Department of Radiotherapy, University of Cologne, Cologne (Germany)

2000-08-01

We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the wobble of the gantry and table rotation movement, the effect of gantry sag, the stereotactic collimator alignment, and the minimal distance between gantry and table rotation axes. Since the method is based on densitometric measurements, beam spot stability is implicitly tested. The method developed is also suitable for quality assurance and has proved to be useful in optimizing isocentric accuracy. The method is simple to perform and only requires a film box and film scanner for instrumentation. Thus, the method has the potential to become widely available and may therefore be useful in standardizing the description of linear accelerator based radiosurgical systems. (author)

On isocentre adjustment and quality control in linear accelerator based radiosurgery with circular collimators and room lasers

International Nuclear Information System (INIS)

Treuer, H.; Kocher, M.; Mueller, R.-P.

2000-01-01

We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the wobble of the gantry and table rotation movement, the effect of gantry sag, the stereotactic collimator alignment, and the minimal distance between gantry and table rotation axes. Since the method is based on densitometric measurements, beam spot stability is implicitly tested. The method developed is also suitable for quality assurance and has proved to be useful in optimizing isocentric accuracy. The method is simple to perform and only requires a film box and film scanner for instrumentation. Thus, the method has the potential to become widely available and may therefore be useful in standardizing the description of linear accelerator based radiosurgical systems. (author)

Quality control, mean glandular dose estimate and room shielding calculation in mammography

International Nuclear Information System (INIS)

Rakotomalala, H.M.

2014-01-01

This study focuses in the importance of Radiation Protection in mammography. A good control of the radiological risk depends on the dose optimization, room shielding calculation and the quality of equipment. The work was carried out in the three private medical centers called A, B, and C. Dosimetry estimates were made on the equipment of the three centers. Values has been compared with the Diagnostic Reference Levels established by the International Atomic Energy Agency (IAEA). Conformity control of the radiological devices has also been done with the Mammographic Quality Control Kit of the INSTN-Madagascar. Verifications of shields of the room containing the mammography equipment were done by theoretical calculations using the method provided by NCRP 147. [fr

Ambient neutron dose equivalent outside concrete vault rooms for 15 and 18 MV radiotherapy accelerators

International Nuclear Information System (INIS)

Martinez-ovalle, S. A.; Barquero, R.; Gomez-ros, J. M.; Lallena, A. M.

2012-01-01

In this work, the ambient dose equivalent, H*(10), due to neutrons outside three bunkers that house a 15- and a 18-MV Varian Clinac 2100C/D and a 15-MV Elekta Inor clinical linacs, has been calculated. The Monte Carlo code MCNPX (v. 2.5) has been used to simulate the neutron production and transport. The complete geometries including linacs and full installations have been built up according to the specifications of the manufacturers and the planes provided by the corresponding medical physical services of the hospitals where the three linacs operate. Two of these installations, those lodging the Varian linacs, have an entrance door to the bunker while the other one does not, although it has a maze with two bends. Various treatment orientations were simulated in order to establish plausible annual equivalent doses. Specifically anterior-posterior, posterior-anterior, left lateral, right lateral orientations and an additional one with the gantry rotated 30 deg. have been studied. Significant dose rates have been found only behind the walls and the door of the bunker, near the entrance and the console, with a maximum of 12 μSv h -1 . Dose rates per year have been calculated assuming a conservative workload for the three facilities. The higher dose rates in the corresponding control areas were 799 μSv y -1 , in the case of the facility which operates the 15-MV Clinac, 159 μSv y -1 , for that with the 15-MV Elekta, and 21 μSv y -1 for the facility housing the 18-MV Varian. A comparison with measurements performed in similar installations has been carried out and a reasonable agreement has been found. The results obtained indicate that the neutron contamination does not increase the doses above the legal limits and does not produce a significant enhancement of the dose equivalent calculated. When doses are below the detection limits provided by the measuring devices available today, MCNPX simulation provides an useful method to evaluate neutron dose equivalents

Out‐of‐field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators

Science.gov (United States)

Cardenas, Carlos E.; Nitsch, Paige L.; Kudchadker, Rajat J.; Howell, Rebecca M.

2016-01-01

Out‐of‐field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high‐energy electron beams. To better understand the extent of these exposures, we measured out‐of‐field dose characteristics of electron applicators for high‐energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out‐of‐field dose profiles and percent depth‐dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out‐of‐field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out‐of‐field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central‐axis, which was found to be higher than typical out‐of‐field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for

Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

Science.gov (United States)

Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

2016-07-08

Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases.

Some folded issues related to over-shielded and unplanned rooms for medical linear accelerators - A case study

Science.gov (United States)

Muhammad, Wazir; Ullah, Asad; Hussain, Amjad; Ali, Nawab; Alam, Khan; Khan, Gulzar; Matiullah; Maeng, Seongjin; Lee, Sang Hoon

2015-08-01

A medical linear accelerator (LINAC) room must be properly shielded to limit the outside radiation exposure to an acceptable safe level defined by individual state and international regulations. However, along with this prime objective, some additional issues are also important. The current case-study was designed to unfold the issues related to over-shielded and unplanned treatment rooms for LINACs. In this connection, an apparently unplanned and over-shielded treatment room of 610 × 610 cm2 in size was compared with a properly designed treatment room of 762 × 762 cm2 in size ( i.e., by following the procedures and recommendations of the IAEA Safety Reports Series No. 47 and NCRP 151). Evaluation of the unplanned room indicated that it was over-shielded and that its size was not suitable for total body irradiation (TBI), although the license for such a treatment facility had been acquired for the installed machine. An overall 14.96% reduction in the total shielding volume ( i.e., concrete) for an optimally planned room as compared to a non-planned room was estimated. Furthermore, the inner room's dimensions were increased by 25%, in order to accommodate TBI patients. These results show that planning and design of the treatment rooms are imperative to avoid extra financial burden to the hospitals and to provide enough space for easy and safe handling of the patients. A spacious room is ideal for storing treatment accessories and facilitates TBI treatment.

Dose properties of x-ray beams produced by laser-wakefield-accelerated electrons

International Nuclear Information System (INIS)

Kainz, K K; Hogstrom, K R; Antolak, J A; Almond, P R; Bloch, C D

2005-01-01

Given that laser wakefield acceleration (LWFA) has been demonstrated experimentally to accelerate electron beams to energies beyond 25 MeV, it is reasonable to assess the ability of existing LWFA technology to compete with conventional radiofrequency linear accelerators in producing electron and x-ray beams for external-beam radiotherapy. We present calculations of the dose distributions (off-axis dose profiles and central-axis depth dose) and dose rates of x-ray beams that can be produced from electron beams that are generated using state-of-the-art LWFA. Subsets of an LWFA electron energy distribution were propagated through the treatment head elements (presuming an existing design for an x-ray production target and flattening filter) implemented within the EGSnrc Monte Carlo code. Three x-ray energy configurations (6 MV, 10 MV and 18 MV) were studied, and the energy width ΔE of the electron-beam subsets varied from 0.5 MeV to 12.5 MeV. As ΔE increased from 0.5 MeV to 4.5 MeV, we found that the off-axis and central-axis dose profiles for x-rays were minimally affected (to within about 3%), a result slightly different from prior calculations of electron beams broadened by scattering foils. For ΔE of the order of 12 MeV, the effect on the off-axis profile was of the order of 10%, but the central-axis depth dose was affected by less than 2% for depths in excess of about 5 cm beyond d max . Although increasing ΔE beyond 6.5 MeV increased the dose rate at d max by more than 10 times, the absolute dose rates were about 3 orders of magnitude below those observed for LWFA-based electron beams at comparable energies. For a practical LWFA-based x-ray device, the beam current must be increased by about 4-5 orders of magnitude. (note)

Fast Neutron Dose Distribution in a Linac Radiotherapy Facility

International Nuclear Information System (INIS)

Al-Othmany, D.Sh.; Abdul-Majid, S.; Kadi, M.W.

2011-01-01

CR-39 plastic detectors were used for fast neutron dose mapping in the radiotherapy facility at King AbdulAziz University Hospital (KAUH). Detectors were calibrated using a 252 Cf neutron source and a neutron dosimeter. After exposure chemical etching was performed using 6N NaOH solution at 70 degree C. Tracks were counted using an optical microscope and the number of tracks/cm 2 was converted to a neutron dose. 15 track detectors were distributed inside and outside the therapy room and were left for 32 days. The average neutron doses were 142.3 mSv on the accelerator head, 28.5 mSv on inside walls, 1.4 mSv beyond the beam shield, and 1 mSv in the control room

Neutron dose to patients treated with high-energy medical accelerators

International Nuclear Information System (INIS)

McGinley, P.H.

2001-01-01

The neutron dose equivalent received by patients treated with high energy x-ray beams was measured in this research. A total of 13 different medical accelerators were evaluated in terms of the neutron dose equivalent in the patient plane and at the beam center. The neutron dose equivalent at the beam center was found to ranged from 0.02 to 9.4 mSv per Sv of x-ray dose and values from 0.029 to 2.58 mSv per Sv of x-ray were measured in the patient plane. It was concluded that the neutron levels meet the International Electrotechnical Commission standard for the patient plane. It was also concluded that when intensity modulated radiation treatment is conducted the neutron dose equivalent received by the patient will increase by a factor of 2 to 10. (author)

Neutron and photon dose assessment in Indus accelerator complex

International Nuclear Information System (INIS)

Verma, Dimple; Haridas Nair, G.; Bandopadhyay, Tapas; Tripathy, R.M.; Pal, Rupali; Bakshi, A.K.; Palani Selvam, T.; Datta, D.

2016-02-01

Indus Accelerator Complex (IAC) consists of 20 MeV Microtron, 450/550 MeV Booster, 450 MeV Indus-1 and 2.5 GeV Indus-2 storage rings. The radiation environment in Indus Accelerator Complex comprises of bremsstrahlung photons, electrons, positrons, photo neutrons and muons, out of which, bremsstrahlung photons are the major constituent of the prompt radiation. Major problem faced for on-line detection of neutrons is their severely pulsed nature. In the present study, measurement of neutron and photon dose rates in Indus Accelerator Complex was carried out using passive dosimeters such as CR-39 solid state nuclear track detector (SSNTD) and CaSO 4 :Dy Teflon disc, 6 LiF:Mg,Ti (TLD 600) and 7 LiF:Mg,Ti (TLD 700) based thermo luminescent (TL) detectors. The report describes the details of the measurement and discusses the results. (author)

Development of a Tandem-ElectroStatic-Quadrupole accelerator facility for Boron Neutron Capture Therapy (BNCT)

International Nuclear Information System (INIS)

Kreiner, A.J.; Thatar Vento, V.; Levinas, P.; Bergueiro, J.; Burlon, A.A.; Di Paolo, H.; Kesque, J.M.; Valda, A.A.; Debray, M.E.; Somacal, H.R.; Minsky, D.M.; Estrada, L.; Hazarabedian, A.; Johann, F.; Suarez Sandin, J.C.; Castell, W.; Davidson, J.; Davidson, M.; Repetto, M.; Obligado, M.; Nery, J.P.; Huck, H.; Igarzabal, M.; Fernandez Salares, A.

2008-01-01

There is a generalized perception that the availability of suitable particle accelerators installed in hospitals, as neutron sources, may be crucial for the advancement of Boron Neutron Capture Therapy (BNCT). An ongoing project to develop a Tandem-ElectroStatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based (AB)-BNCT is described here. The project goal is a machine capable of delivering 30 mA of 2.4-2.5 MeV protons to be used in conjunction with a neutron production target based on the 7 Li(p,n) 7 Be reaction slightly beyond its resonance at 2.25 MeV. A folded tandem, with 1.20-1.25 MV terminal voltage, combined with an ESQ chain is being designed and constructed. This machine is conceptually shown to be capable of accelerating a 30 mA proton beam to 2.5 MeV. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams, based on the 7 Li(p,n) 7 Be reaction, to perform BNCT treatment for deep-seated tumors in less than an hour. This electrostatic machine is one of the technologically simplest and cheapest solutions for optimized AB-BNCT. At present there is no BNCT facility in the world with the characteristics presented in this work. For the accelerator, results on its design, construction and beam transport calculations are discussed. Taking into account the peculiarities of the expected irradiation field, the project also considers a specific study of the treatment room. This study aims at the design of the treatment room emphasizing aspects related to patient, personnel and public radiation protection; dose monitoring; patient positioning and room construction. The design considers both thermal (for the treatment of shallow tumors) and epithermal (for deep-seated tumors) neutron beams entering the room through a port connected to the accelerator via a moderation and neutron beam shaping assembly. Preliminary results of dose calculations for the treatment room design, using the MCNP program, are presented

Technical Note: Mobile accelerator guidance using an optical tracker during docking in IOERT procedures.

Science.gov (United States)

Marinetto, Eugenio; Victores, Juan González; García-Sevilla, Mónica; Muñoz, Mercedes; Calvo, Felipe Ángel; Balaguer, Carlos; Desco, Manuel; Pascau, Javier

2017-10-01

Intraoperative electron radiation therapy (IOERT) involves the delivery of a high radiation dose during tumor resection in a shorter time than other radiation techniques, thus improving local control of tumors. However, a linear accelerator device is needed to produce the beam safely. Mobile linear accelerators have been designed as dedicated units that can be moved into the operating room and deliver radiation in situ. Correct and safe dose delivery is a key concern when using mobile accelerators. The applicator is commonly fixed to the patient's bed to ensure that the dose is delivered to the prescribed location, and the mobile accelerator is moved to dock the applicator to the radiation beam output (gantry). In a typical clinical set-up, this task is time-consuming because of safety requirements and the limited degree of freedom of the gantry. The objective of this study was to present a navigation solution based on optical tracking for guidance of docking to improve safety and reduce procedure time. We used an optical tracker attached to the mobile linear accelerator to track the prescribed localization of the radiation collimator inside the operating room. Using this information, the integrated navigation system developed computes the movements that the mobile linear accelerator needs to perform to align the applicator and the radiation gantry and warns the physician if docking is unrealizable according to the available degrees of freedom of the mobile linear accelerator. Furthermore, we coded a software application that connects all the necessary functioning elements and provides a user interface for the system calibration and the docking guidance. The system could safeguard against the spatial limitations of the operating room, calculate the optimal arrangement of the accelerator and reduce the docking time in computer simulations and experimental setups. The system could be used to guide docking with any commercial linear accelerator. We believe that the

Therapeutic dose from a pyroelectric electron accelerator.

Science.gov (United States)

Fullem, T Z; Fazel, K C; Geuther, J A; Danon, Y

2009-11-01

Simple heating of pyroelectric crystals has been used as the basis for compact sources of X rays, electrons, ions and neutrons. We report on the evaluation of the feasibility of using a portable pyroelectric electron accelerator to deliver a therapeutic dose to tissue. Such a device could be mass produced as a handheld, battery-powered instrument. Experiments were conducted with several crystal sizes in which the crystal was heated inside a vacuum chamber and the emitted electrons were allowed to penetrate a thin beryllium window into the surrounding air. A Faraday cup was used to count the number of electrons that exited the window. The energy of these electrons was determined by measuring the energy spectrum of the X rays that resulted from the electron interactions with the Faraday cup. Based on these measurements, the dose that this source could deliver to tissue was calculated using Monte Carlo calculations. It was found that 10(13) electrons with a peak energy of the order of 100 keV were emitted from the beryllium window and could deliver a dose of 1664 Gy to a 2-cm-diameter, 110-microm-deep region of tissue located 1.5 cm from the window with air between the window and the tissue. This dose level is high enough to consider this technology for medical applications in which shallow energy deposition is beneficial.

Control room lay-out

International Nuclear Information System (INIS)

Toma, Violeta

2004-01-01

TRIUMF (Tri-University Meson Facility) is Canada's national laboratory for particle and nuclear physics. There are 6 accelerators and 3 Control Rooms at TRIUMF. The main control room serves the big cyclotron, the 500 MeV, and the adjacent experiment. The 42 MeV and two 32 MeV ones are production dedicated. These cyclotrons belong to a private company but are operated by TRIUMF staff from ATG (Applied Technology Group) Control Room. The last is ISAC (Isotope Acceleration and Separation) Control Room, from which the LINAC is controlled. Research areas cover theoretical (2 subjects), pure (5 subjects) and applied (8 subjects) physics. In the early '70s, as the 500 MeV was being completed, the first Control Room was built in the main accelerator building. The recent topics covered by this paper are proton and pion therapy, what are the operator's duties?, the CP42, TR30 and TR13 cyclotron control rooms, the ISAC control systems including control room modification. Due to the nature of an operator's job, the Control Room layout is pretty important. This is true for any work environment, but when working shifts it becomes essential. Lots of time and effort, not to mention money, were spent to figure out the optimum configuration. It seems to me that the key factor in the control room layout is versatility, and this is because it has to keep happy a group of people with different inclinations, which have a tendency to become quite moody after the second night shift. No matter what, there will still be unhappy people, but we are trying our best. (Y. Tanaka)

Design and construction of the clean room for proton beam accelerator assembly

International Nuclear Information System (INIS)

Park, J. S.; Song, I. T.

2000-09-01

The objective of this report is to design, construction and evaluation of clean room for proton beam accelerator assembly. The design conditions o Class : 1,000(1,000 ea ft 3 ), o Flow Rate : 200 m 3 /h m 2 , o Temperature : 22 deg C±2, o Humidity : 55%±5. The main design results are summarized as follows: o Air-handling unit : Cooling Capacity : 13,500 kcal/h, Heating Capacity : 10,300 kcal/h, Humidity Capacity : 4 kg/h, Flow Rate : 150 CMM o Air Shower : Flow Rate : 35 CMM, Size : 1500 x 1000 x 2200, Material : In-steel, Out-SUS304, Filter : PRE + HEPA, AIR Velocity : 25 m/s o Relief Damper : Size : Φ250, Casing : SS41, Blade : AL, Shaft : SUS304, Weight Ring : SS41, Grill : AL o HEPA Filter Box : Filter Box Size : 670 x 670 x 630, Filter Size : 610 x 610 x 150, Frame: Poly Wood, Media : Glass Fiber, Filter Efficiency : 0.3μm, 99.97%, Separator : AL, Flow Rate : 17 CMM, Damper Size : Φ300 Following this report will be used important data for the design, construction, operation and maintenance of the clean room, for high precision apparatus assembly laboratory

Shielding Calculations for Industrial 5/7.5MeV Electron Accelerators Using the MCNP Monte Carlo Code

International Nuclear Information System (INIS)

Peri, E.; Orion, I.

2014-01-01

High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, in order to extend the shelf life of products. High energy photons can cause food activation due to (D 3 ,n) reactions. Until 2004, to eliminate the possibility of food activation, the electron energy was limited to 5 MeV X-rays for food irradiation. In 2004, the FDA approved the usage of up to 7.5 MeV, but only with tantalum and gold targets (1). Higher X-ray energy results an increased flux of X-rays in the forward direction, increased penetration, and higher photon dose rate due to better electron-to-photon conversion. These improvements could decrease the irradiation time and allow irradiation of larger packages, thereby providing higher production rates with lower treatment cost. Medical accelerators usually work with 6-18 MV electron energy with tungsten target to convert the electron beam to X-rays. In order to protect the patients, the accelerator head is protected with a heavy lead shielding; therefore, the bremsstrahlung is emitted only in the forward direction. There are many publications and standards that guide how to design optimal shielding for medical accelerator rooms. The shielding data for medical accelerators is not applicable for industrial accelerators, since the data is for different conversion targets, different X-Ray energies, and only for the forward direction. Collimators are not always in use in industrial accelerators, and therefore bremsstrahlung photons can be emitted in all directions. The bremsstrahlung spectrum and dose rate change as a function of the emission angle. The dose rate decreases from maximum in the forward direction (0°) to minimum at 180° by 1-2 orders of magnitude. In order to design and calculate optimal shielding for food accelerator rooms, there is a need to have the bremsstrahlung spectrum data, dose rates and concrete attenuation data in all emission directions

Evaluation of area monitor response for neutrons in radiation field generated by a 15 MV clinic accelerator

International Nuclear Information System (INIS)

Salgado, Ana Paula

2011-01-01

The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)

Radioprotection of patients in radiotherapy: the gonadal doses resulting from treatments at electron accelerators

International Nuclear Information System (INIS)

Nuesslin, F.; Hassenstein, E.

1977-01-01

Using LiF-dosemeters in a polystyrene phantom dose profiles have been measured. The influence of the following parameters has been studied: accelerator type, primary beam quality (45 and 8 MV X-rays, 45, 18 and 10 MeV electrons), orientation of the phantom, depth in the phantom (0, 1 and 10 cm) and thickness of additional lead sheets put on the phantom surface. Because the dose distribution of the leakage radiation of the accelerator depends mainly on the mechanism of beam production, i.e. on the accelerator type, different anisotropic isodose-patterns have been found. For instance, in case of the betatron the dose maxima are located at opposite sides within the plane of electron orbits. On the other side, there does not exist any favourable direction femal patients should be positioned at to minimize the gonadal dose, because already at 10 cm depth in the phantom the isodose distributions are nearly isotropic. This is caused by the low penetrating capacity of the leakage radiation (2 to 0.6 mm Pb HVL thickness at 45 MV X-rays, depending on the lateral distance from the field). These findings suggest to cover the gonads of male patients undergoing radiotherapy with lead sheets of 1 or 2 mm thickness

Evaluation of the space scattered dose according to the position of the radiation workers in mammography room

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Yeon [Dept. of Radiation Oncology, Dongnam Inst. of Radiological and Medical Science, Busan (Korea, Republic of); Lee, Jin Soo [Dept. of Radiology, Inje University Heaundae Paik Hospital, Busan (Korea, Republic of)

2016-09-15

This study was conducted to evaluate the dose of the space to the controller located within the mammography room conducted a research on ways to the reduction exposure to the radiation workers. Results, the dose of 6.18 mGy/year was measured when there is no difference in the hilar area of the controller position, the dose of 2.35E-11 mGy/year was measured when installing the Shielding door. In addition, when the direction of the X-ray tube anode be heading this direction controller, low average level measured was 0.30 mGy/year. Based on this study, the mammography should be considered when installing the anode and cathod directions. And, by installing the shielding door, it must be able to completely separate shooting space and control room. This is the best way radiation protection method in radiation workers.

Technical Note: Comparison of peripheral patient dose from MR-guided 60 Co therapy and 6 MV linear accelerator IGRT.

Science.gov (United States)

Hauri, Pascal; Hälg, Roger A; Schneider, Uwe

2017-07-01

The use of X-ray imaging in radiation therapy can give a substantial dose to the patient. A Cobalt machine combined with an magnetic resonance imaging (MRI) was recently introduced to clinical work. One positive aspect of using non-ionizing imaging devices is the reduction of the patient exposure. The purpose of this study was to quantify the difference in out-of-field dose to the patient between the image guided radiation therapy (IGRT) treatment applied with a linear accelerator with cone beam CT (CBCT) equipment and a Cobalt machine combined with an MRI. The treatment of a rhabdomyosarcoma in the prostate was planned and irradiated using different modalities and radiation therapy machines. The whole-body dose was measured for a 3D-conformal radiation therapy (3DCRT), an intensity-modulated radiation therapy (IMRT), and a volumetric-modulated arc therapy plan applied with a conventional linear accelerator operated at 6 MV beam energy. Additionally, the dose of an IMRT plan applied with a 60 Co machine combined with an MRI was measured. Furthermore, the dose of one CBCT scan using the linear accelerator's on-board imaging system was determined. The 3D dose measurements were performed in an anthropomorphic phantom containing 168 slots for thermoluminescence dosimeters (TLDs). A combination of LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P (TLD100H) was used to accurately determine the in- and out-of-field dose. The plans were rescaled to different fractionation schemes (2 Gy, 3 Gy, and 5 Gy fraction dose) and the dose of one CBCT scan was additionally added to the treatment dose per fraction applied with the linear accelerator. The resulting absorbed doses per fraction of the two machines were compared. In the target region, all measured treatment plans presented the same magnitude of dose, while the CBCT dose was a factor of 100 smaller. Close to the planned target volume (PTV), the dose from the 60 Co machine was a factor of two higher compared with the 3DCRT + CBCT dose. Up

Dose assessment method for control room habitability in accident condition in nuclear power plants

International Nuclear Information System (INIS)

Yang Dong; Tang Shaohua; Wang Jianhua

2012-01-01

Based on the NRC. technical requirements on NPP control room habitability assessment, and considering the characteristics of the improved second generation NPPs in China, this paper developed a complete dose assessment model for control room habitability. Contrasting to the existing model in China, this model is applicable for DBA and sever accident, and the short term atmospheric diffusion factor can be calculated using the combined wake mode. By considering the zoning of habitable area and the design characteristics of the ventilation system, the effects of un-filtrated air leakage from the building and the ventilation system on the assessment calculation can be considered. (authors)

Evaluation of the environmental equivalent dose rate using area monitors for neutrons in clinical linear accelerators

International Nuclear Information System (INIS)

Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Batista, Delano V.S.

2009-01-01

The Neutron Laboratory of the Radioprotection and Dosimetry Institute - IRD/CNEN, Rio de Janeiro, Brazil, initiated studies on the process of calibration of neutron area monitors and the results of the measurements performed at radiotherapy treatment rooms, containing clinical accelerators

Serial measurement of radiation leakage dose rates in safekeeping at the Gammaknife room

International Nuclear Information System (INIS)

Baba, Sadaaki; Nozaki, Kenichi; Toyoda, Tatsuya; Wakamatsu, Osamu; Machida, Toru

2006-01-01

We report the serial measurement of leakage dose rates in safekeeping at the Gammaknife room during the past 4 years and 9 months by scintillation survey meter. The leakage dose rates at the radiation boundaries were the same as the natural background levels. Leakage dose rates at each shield calculation point from two 90 Sr calibration sources contained in the storehouse were negligible compared with those from 60 Co sources of the Gammaknife. 60 Co sources of the Gammaknife are arranged in 201 pieces at 10 degree interval on the circumference and in five lines within an arc of 35 degrees. Its shield container is made of iron at least 43 cm thick. We got leakage dose rates less than 40% of the calculated values. We think it is caused by the difference of each actual distance and shield thickness because 60 Co sources are usually considered as a point source in the shield calculation. There are shutters opening up and down when patients go in and out to the direction of the couch. The leakage values to this direction were about twice as much as the calculated value. So, we knew the thickness of those shutters was thinner than 43 cm. The half life time of 60 Co source calculated from the serial measurements of leakage dose rates was 4.93 years on average. It is 94% of the physical half life value of 5.27 years. We judged it was acceptable considering the difficulty of measuring low dose rate level with the radiation survey meter. Very strong correlation was observed between the decrease of 60 Co dose rate acquired from one minute measurement at the center of 18 cm diameter polysterene phantom gotten from December 2000 to August 2005 and that of computation based on the physical half life time. Likewise there was strong and more correlation with leakage dose rate in the Gammaknife room. From this, we deduce the leakage dose rate decreases according to the theory of the disintegration of radioactivity with passage of time. Revised radiation related laws took effect

Accelerators for Medical Applications What is so Special?

CERN Document Server

Schippers, J.M.

2016-01-01

Specific requirements of accelerators for radiation therapy with protons or ions will be discussed. The focus will be on accelerator design, operational and formal aspects. We will discuss the special requirements to reach a high reliability for patient treatments as well as an accurate delivery of the dose at the correct position in the patient using modern techniques like pencil beam scanning. It will be shown that the requirements of the accelerated beam differ from those in a nuclear physics laboratory. The way of operating such a medical device requires not only operators, but also the possibility to have a safe machine operation by non accelerator specialists at different operating sites (treatment rooms). It will be shown that the organisation and role of the control/interlock system can be considered as being the most dedicated in a particle-therapy providing facility.

Design and construction of the clean room for proton beam accelerator assembly

Energy Technology Data Exchange (ETDEWEB)

Park, J. S.; Song, I. T

2000-09-01

The objective of this report is to design, construction and evaluation of clean room for proton beam accelerator assembly. The design conditions o Class : 1,000(1,000 ea ft{sup 3}), o Flow Rate : 200 m{sup 3}/h m{sup 2}, o Temperature : 22 deg C{+-}2, o Humidity : 55%{+-}5. The main design results are summarized as follows: o Air-handling unit : Cooling Capacity : 13,500 kcal/h, Heating Capacity : 10,300 kcal/h, Humidity Capacity : 4 kg/h, Flow Rate : 150 CMM o Air Shower : Flow Rate : 35 CMM, Size : 1500 x 1000 x 2200, Material : In-steel, Out-SUS304, Filter : PRE + HEPA, AIR Velocity : 25 m/s o Relief Damper : Size : {phi}250, Casing : SS41, Blade : AL, Shaft : SUS304, Weight Ring : SS41, Grill : AL o HEPA Filter Box : Filter Box Size : 670 x 670 x 630, Filter Size : 610 x 610 x 150, Frame: Poly Wood, Media : Glass Fiber, Filter Efficiency : 0.3{mu}m, 99.97%, Separator : AL, Flow Rate : 17 CMM, Damper Size : {phi}300 Following this report will be used important data for the design, construction, operation and maintenance of the clean room, for high precision apparatus assembly laboratory.

The HYP-RT Hypoxic Tumour Radiotherapy Algorithm and Accelerated Repopulation Dose per Fraction Study

Directory of Open Access Journals (Sweden)

W. M. Harriss-Phillips

2012-01-01

Full Text Available The HYP-RT model simulates hypoxic tumour growth for head and neck cancer as well as radiotherapy and the effects of accelerated repopulation and reoxygenation. This report outlines algorithm design, parameterisation and the impact of accelerated repopulation on the increase in dose/fraction needed to control the extra cell propagation during accelerated repopulation. Cell kill probabilities are based on Linear Quadratic theory, with oxygenation levels and proliferative capacity influencing cell death. Hypoxia is modelled through oxygen level allocation based on pO2 histograms. Accelerated repopulation is modelled by increasing the stem cell symmetrical division probability, while the process of reoxygenation utilises randomised pO2 increments to the cell population after each treatment fraction. Propagation of 108 tumour cells requires 5–30 minutes. Controlling the extra cell growth induced by accelerated repopulation requires a dose/fraction increase of 0.5–1.0 Gy, in agreement with published reports. The average reoxygenation pO2 increment of 3 mmHg per fraction results in full tumour reoxygenation after shrinkage to approximately 1 mm. HYP-RT is a computationally efficient model simulating tumour growth and radiotherapy, incorporating accelerated repopulation and reoxygenation. It may be used to explore cell kill outcomes during radiotherapy while varying key radiobiological and tumour specific parameters, such as the degree of hypoxia.

The use of steel and lead shieldings in radiotherapy rooms and its comparison with respect to neutrons doses at patients; Comparacao de blindagens de aco e de chumbo usadas em salas de radioterapia quanto a dose devido a neutrons depositada em pacientes

Energy Technology Data Exchange (ETDEWEB)

Silva, M.G.; Rebello, W.F.; Andrade, E.R.; Medeiros, M.P.C.; Mendes, R.M.S.; Braga, K.L.; Gomes, R.G., E-mail: maglosilva15@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: kelmo.lins@gmail.com, E-mail: ggrprojetos@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia; Silva, Ademir X., E-mail: ademir@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

2015-07-01

The NCRP Report No. 151, Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities, considers, in shielding calculations for radiotherapy rooms, the use of lead and/or steel to be applied on bunker walls. The NCRP Report calculations were performed foreseeing a better protection of people outside the radiotherapy room. However, contribution of lead and steel to patient dose should be taken into account for radioprotection purposes. This work presents calculations performed by MCNPX code in analyzing the Ambient Dose Equivalent due to neutron, H*(10){sub n}, within a radiotherapy room, in the patients area, considering the use of additional shielding of 1 TVL of lead or 1 TVL of steel, positioned at the inner faces of walls and ceiling of a bunker. The head of the linear accelerator Varian 2100/2300 C/D was modeled working at 18MeV, with 5x5cm{sup 2}, 10x10cm{sup 2}, 20x20cm{sup 2}, 30x30cm{sup 2} and 40x40cm{sup 2} openings for jaws and MLC and operating in eight gantry's angles. This study shows that the use of lead generates an average value of H*(10){sub n} at patients area, 8.02% higher than the expected when using steel. Further studies should be performed based on experimental data for comparison with those from MCNPX simulation.

Calculation of the neutrons shielding in cyclotron accelerator

International Nuclear Information System (INIS)

Ribeiro, Martha S.; Sanches, Matias P.; Rodrigues, Demerval L.

2000-01-01

The objective of radioprotection in cyclotron facilities is to reduce the dose levels in the workplaces to classify them like supervised areas. In this way, the radiation dose rates in areas occupied by workers during cyclotron operations should not exceed 7,5 μSv/h. In controlled areas these levels are not observed and some rigorous controls must be exerted by administrative procedures or protection mechanisms. The Cyclotron Laboratory at IPEN-CNEN/SP has a cyclotron model Cyclone 30, 30 MeV, used for research and it is also used for radioisotopes production for medical diagnosis and therapeutical applications. Among them, 123 I, 67 Ga and 18 F can be pointed. When accelerator is operating, failures in perforations and paths that conduce to room accelerator can be occur and thus, the dose levels are higher than that established by law. For this reason, a review for shielding structure was necessary in order to optimize radiation dose. The purpose of this work was to determine the shielding thickness and adequate material to diminish the dose rates in workplaces to a value below 7,5 μSv/h. It was used a method to employ the equivalent dose value in the facility areas for neutrons fluency rate for the principal reactions in target irradiation processes. The purposed shielding for the vault doors ensures dose levels lower than established limits to supervised areas. (author)

Control room habitability during severe accidents

International Nuclear Information System (INIS)

Siu, R.P.

1989-01-01

The requirements for protection of control room personnel against radiation hazards are specified in 10CFR50, Appendix A, GDC 19. The conventional approach involves a mechanistic evaluation of the radiation doses to control room personnel during design-basis accidents. In this study, an assessment of control room habitability during severe accidents is conducted. The potential levels of radiation hazards to control room personnel are evaluated in terms of both magnitude and probability of occurrence. The expected values for the probabilities of exceeding GDC-19 limits and the cumulative probability distributions of control room doses are determined. In this study, a pressurized water reactor with a large dry containment has been selected for analysis. The types of control rooms evaluated in this study include designs with: (a) filtered local intakes only, (b) filtered recirculation only, (c) filtered local intakes and recirculation, and (d) filtered dual remote intakes and recirculation. From the observations, it is concluded that, except for control room D, all other control room designs may require improvements in order to provide adequate radiation protection during severe accidents, particularly in terms of reducing whole-body gamma doses and skin doses. Potential design improvements include reduction of intake flows for concepts relying on pressurization, reduction in overall leakages, and control room pressurization through the use of bottled air supply

Accelerated postirradiation recovery of hematopoietic marrow following priming with low doses of vincristine

International Nuclear Information System (INIS)

Johnke, R.M.; Abernathy, R.S.

1990-01-01

The present investigation is a continuation of efforts to characterize the radioprotective potential of priming with vincristine (VcR). In this study, the postirradiation recovery kinetics of the marrow's hematopoietic stem cell, progenitor cell, and stromal cell compartments were monitored following exposure to a range of sublethal radiation doses to determine (a) the optimal VcR/radiation intertreatment interval for achieving maximal hematopoietic protection, (b) whether this optimal interval is influenced by the dose of radiation administered, and (c) whether the radioprotection observed involves the hematopoietic stroma. The results demonstrate that the degree of radioprotection observed was significantly influenced by the scheduling of the VcR priming dose with respect to the radiation exposure. An intertreatment interval of 24 h provided maximal radioprotective benefit irrespective of the radiation dose administered. Additionally, the radioprotection following VcR priming appeared to be more the result of an accelerated recovery in the hematopoietic stem cell and progenitor cell compartments than a change in their intrinsic radiosensitivity. The data also suggest that this accelerated recovery was not a consequence of greater radioprotection of marrow stroma. Finally, the radioprotection observed following VcR priming did not appear to involve a selective lineage response by either the erythroid or the granulomonocytic progenitor compartments

Dose linearity and uniformity of a linear accelerator designed for implementation of multileaf collimation system-based intensity modulated radiation therapy

International Nuclear Information System (INIS)

Saw, Cheng B.; Li Sicong; Ayyangar, Komanduri M.; Yoe-Sein, Maung; Pillai, Susha; Enke, Charles A.; Celi, Juan C.

2003-01-01

The dose linearity and uniformity of a linear accelerator designed for multileaf collimation system- (MLC) based IMRT was studied as a part of commissioning and also in response to recently published data. The linear accelerator is equipped with a PRIMEVIEW, a graphical interface and a SIMTEC IM-MAXX, which is an enhanced autofield sequencer. The SIMTEC IM-MAXX sequencer permits the radiation beam to be 'ON' continuously while delivering intensity modulated radiation therapy subfields at a defined gantry angle. The dose delivery is inhibited when the electron beam in the linear accelerator is forced out of phase with the microwave power while the MLC configures the field shape of a subfield. This beam switching mechanism reduces the overhead time and hence shortens the patient treatment time. The dose linearity, reproducibility, and uniformity were assessed for this type of dose delivery mechanism. The subfields with monitor units ranged from 1 MU to 100 MU were delivered using 6 MV and 23 MV photon beams. The doses were computed and converted to dose per monitor unit. The dose linearity was found to vary within 2% for both 6 MV and 23 MV photon beam using high dose rate setting (300 MU/min) except below 2 MU. The dose uniformity was assessed by delivering 4 subfields to a Kodak X-OMAT TL film using identical low monitor units. The optical density was converted to dose and found to show small variation within 3%. Our results indicate that this linear accelerator with SIMTEC IM-MAXX sequencer has better dose linearity, reproducibility, and uniformity than had been reported

Measurements of the personal dose equivalent

International Nuclear Information System (INIS)

Scarlat, F.; Scarisoreanu, A.; Badita, E.; Oane, M.; Mitru, E.

2008-01-01

Full text: The paper presents the results of measurements related to the personal dose equivalent in the rooms adjacent to NILPRP 7 MeV linear accelerator, by means of the secondary standard chamber T34035 Hp(10). The chamber was calibrated by PTB at S- 137 Cs (E av = 661.6 keV, T 1/2 11050 days) and has N H = 3.17x10 6 Sv/C calibration factor for the personal dose equivalent, Hp(10), at a depth of 10 mm in climatic reference conditions. The measurements were made for the two operation mode of the 7 MeV linac: electrons and bremsstrahlung

The radiation dose dilemma in the hybrid operating room

NARCIS (Netherlands)

de Ruiter, QMB

2016-01-01

The of the hybrid Operation room (an operation room combined with advanced radiological X-ray equipment) is gaining popularity, as it is now the preferred room to perform (complex) endovascular aortic procedures. The fixed C-arms equipped in these rooms make it possible to gain very high image

Response of rat spinal cord to single and fractionated doses of accelerated heavy ions

International Nuclear Information System (INIS)

Leith, J.L.; McDonald, M.; Powers-Risius, P.; Bliven, S.F.; Walton, R.E.; Woodruff, K.H.; Howard, J.

1980-01-01

The response of rat spinal cord to irradiation with accelerated heavy ions, in particular carbon and neon ions has been studied. Two different ionization regions in the modified Bragg curve for each ion have been studied for both single and fractionated exposures. We have defined the paralytic response as a function of dose and dose per fraction, and we have determined RBE and repair values. The response of rat spinal cord is both dose and LET dependent, which allows the derivation of RBE and repair values

Evaluation of the Induced Activity in Air by the External Proton Beam in the Target Room of the Proton Accelerator Facility of Proton Engineering Frontier Project

International Nuclear Information System (INIS)

Lee, Cheol Woo; Lee, Young Ouk; Cho, Young Sik; Ahn, So Hyun

2007-01-01

One of the radiological concerns is the worker's exposure level and the concentration of the radionuclides in the air after shutdown, for the safety analysis on the proton accelerator facility. Although, the primary radiation source is the protons accelerated up to design value, all of the radio-nuclide is produced from the secondary neutron and photon induced reaction in air. Because, the protons don't penetrate the acceleration equipment like the DTL tank wall or BTL wall, secondary neutrons or photons are only in the air in the accelerator tunnel building because of the short range of the proton in the materials. But, for the case of the target rooms, external proton beams are occasionally used in the various experiments. When these external proton beams travel through air from the end of the beam transport line to the target, they interact directly with air and produce activation products from the proton induced reaction. The external proton beam will be used in the target rooms in the accelerator facility of the Proton Accelerator Frontier Project (PEFP). In this study, interaction characteristics of the external proton beam with air and induced activity in air from the direct interaction of the proton beam were evaluated

Dose properties of a laser accelerated electron beam and prospects for clinical application

International Nuclear Information System (INIS)

Kainz, K.K.; Hogstrom, K.R.; Antolak, J.A.; Almond, P.R.; Bloch, C.D.; Chiu, C.; Fomytskyi, M.; Raischel, F.; Downer, M.; Tajima, T.

2004-01-01

Laser wakefield acceleration (LWFA) technology has evolved to where it should be evaluated for its potential as a future competitor to existing technology that produces electron and x-ray beams. The purpose of the present work is to investigate the dosimetric properties of an electron beam that should be achievable using existing LWFA technology, and to document the necessary improvements to make radiotherapy application for LWFA viable. This paper first qualitatively reviews the fundamental principles of LWFA and describes a potential design for a 30 cm accelerator chamber containing a gas target. Electron beam energy spectra, upon which our dose calculations are based, were obtained from a uniform energy distribution and from two-dimensional particle-in-cell (2D PIC) simulations. The 2D PIC simulation parameters are consistent with those reported by a previous LWFA experiment. According to the 2D PIC simulations, only approximately 0.3% of the LWFA electrons are emitted with an energy greater than 1 MeV. We studied only the high-energy electrons to determine their potential for clinical electron beams of central energy from 9 to 21 MeV. Each electron beam was broadened and flattened by designing a dual scattering foil system to produce a uniform beam (103%>off-axis ratio>95%) over a 25x25 cm2 field. An energy window (ΔE) ranging from 0.5 to 6.5 MeV was selected to study central-axis depth dose, beam flatness, and dose rate. Dose was calculated in water at a 100 cm source-to-surface distance using the EGS/BEAM Monte Carlo algorithm. Calculations showed that the beam flatness was fairly insensitive to ΔE. However, since the falloff of the depth-dose curve (R 10 -R 90 ) and the dose rate both increase with ΔE, a tradeoff between minimizing (R 10 -R 90 ) and maximizing dose rate is implied. If ΔE is constrained so that R 10 -R 90 is within 0.5 cm of its value for a monoenergetic beam, the maximum practical dose rate based on 2D PIC is approximately 0.1 Gy min-1

Scattered fractions of dose from 18 and 25 MV X-ray radiotherapy linear accelerators

International Nuclear Information System (INIS)

Shobe, J.; Rodgers, J.E.; Taylor, P.L.; Jackson, J.; Popescu, G.

1996-01-01

Over the years, measurements have been made at a few energies to estimate the scattered fraction of dose from the patient in medical radiotherapy operations. This information has been a useful aid in the determination of shielding requirements for these facilities. With these measurements, known characteriztics of photons, and various other known parameters, Monte Carlo codes are being used to calculate the scattered fractions and hence the shielding requirements for the photons of other energies commonly used in radiotherapeutic applications. The National Institute of Standards and Technology (NIST) acquired a Sagittaire medical linear accelerator (linac) which was previously located at the Yale-New Haven Hospital. This linac provides an X-ray beam of 25 MV photons and electron beams with energies up to 32 MeV. The housing on the gantry was permanently removed from the accelerator during installation. A Varian Clinac 1800 linear accelerator was used to produce the 18 MV photons at the Frederick Memorial Hospital Regional Cancer Therapy Center in Frederick, MD. This paper represents a study of the photon dose scattered from a patient in typical radiation treatment situations as it relates to the dose delivered at the isocenter in water. The results of these measurements will be compared to Monte Carlo calculations. Photon spectral measurements were not made at this time. Neutron spectral measurements were made on this Sagittaire machine in its previous location and that work was not repeated here, although a brief study of the neutron component of the 18 and 25 MV linacs was performed utilizing thermoluminescent dosimetry (TLD) to determine the isotropy of the neutron dose. (author)

Dose characteristics of in-house-built collimators for stereotactic radiotherapy with a linear accelerator

International Nuclear Information System (INIS)

Norrgaard, F. Stefan E.; Kulmala, Jarmo A.J.; Minn, Heikki R.I.; Sipilae, Petri M.

1998-01-01

Dose characteristics of a stereotactic radiotherapy unit based on a standard Varian Clinac 4/100 4 MV linear accelerator, in-house-built Lipowitz collimators and the SMART stereotactic radiotherapy treatment planning software have been determined. Beam collimation is constituted from the standard collimators of the linear accelerator and a tertiary collimation consisting of a replaceable divergent Lipowitz collimator. Four collimators with isocentre diameters of 15, 25, 35 and 45 mm, respectively, were constructed. Beam characteristics were measured in air, acrylic or water with ionization chamber, photon diode, electron diode, diamond detector and film. Monte Carlo simulation was also applied. The radiation leakage under the collimators was less than 1% at 50 mm depth in water. Specific beam characteristics for each collimator were imported to SMART and dose planning with five non-coplanar converging 140 deg. arcs separated by 36 deg. angles was performed for treatment of a RANDO phantom. Dose verification was made with TLD and radiochromic film. The in-house-built collimators were found to be suitable for stereotactic radiotherapy and patient treatments with this system are in progress. (author)

Analytic characterization of linear accelerator radiosurgery dose distributions for fast optimization

International Nuclear Information System (INIS)

Meeks, S.L.; Buatti, J.M.; Eyster, B.; Kendrick, L.A.

1999-01-01

Linear accelerator (linac) radiosurgery utilizes non-coplanar arc therapy delivered through circular collimators. Generally, spherically symmetric arc sets are used, resulting in nominally spherical dose distributions. Various treatment planning parameters may be manipulated to provide dose conformation to irregular lesions. Iterative manipulation of these variables can be a difficult and time-consuming task, because (a) understanding the effect of these parameters is complicated and (b) three-dimensional (3D) dose calculations are computationally expensive. This manipulation can be simplified, however, because the prescription isodose surface for all single isocentre distributions can be approximated by conic sections. In this study, the effects of treatment planning parameter manipulation on the dimensions of the treatment isodose surface were determined empirically. These dimensions were then fitted to analytic functions, assuming that the dose distributions were characterized as conic sections. These analytic functions allowed real-time approximation of the 3D isodose surface. Iterative plan optimization, either manual or automated, is achieved more efficiently using this real time approximation of the dose matrix. Subsequent to iterative plan optimization, the analytic function is related back to the appropriate plan parameters, and the dose distribution is determined using conventional dosimetry calculations. This provides a pseudo-inverse approach to radiosurgery optimization, based solely on geometric considerations. (author)

Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off

Energy Technology Data Exchange (ETDEWEB)

Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

2011-03-15

Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group

Evaluation of room air cleaners for the reduction of exposure and dose to indoor radon progeny

International Nuclear Information System (INIS)

Hopke, P.K.; Jensen, B.; Wasiolek, P.

1994-01-01

Since the proximate source of dose to the cells of the bronchial epithelium is the deposited radon progeny, the exposure and resulting dose could be reduced if the radon decay products were effectively removed from the indoor atmosphere. Thus, room air cleaners could be effective in reducing the risks associated with indoor radon. However, because of the short half-life of 218 Po, it grows back quickly and in the altered aerosol conditions that are produced by the presence of an air cleaner, the exposure/dose conditions as well as the magnitude of the dose can be substantially changed. To examine the nature of the exposure of individuals in normally occupied homes and to determine the effect of various types of room air cleaners on the exposure to and dose from the indoor radon progeny, a series of measurements have been made using an automated graded screen array system. Two extended experiments were performed in homes in Arnprior, Ontario and Parishville, NY, in which filtration systems, a positive ion electrostatic precipitator, and ioniser/fan systems have been tested for their ability to remove both airborne radioactivity and particles. In both experiments, measurements were made over one week periods with an air cleaner operating and the distributions of exposure are compared with measurements of the background conditions when no cleaner is functioning. The doses to both basal and secretory cells of the bronchial epithelium in the first eight generations of the bronchus were calculated using the model developed by James and their distributions are compared among the various exposure conditions. In most cases the presence of the air cleaner reduced the exposure to radon progeny. However, the reductions in dose were generally substantially smaller than the reductions in exposure. In the intercomparisons of the two filtration units and the two identical ioniser/fan systems, the units generally behaved in a similar manner. The results of this substantial set of

Determination of the exposure speed of radiation emitted by the linear accelerator, using the code MCNP5 to evaluate the radiotherapy room shields of ABC Hospital

International Nuclear Information System (INIS)

Corral B, J. R.

2015-01-01

Humans should avoid exposure to radiation, because the consequences are harmful to health. Although there are different emission sources of radiation, generated by medical devices they are usually of great interest, since people who attend hospitals are exposed in one way or another to ionizing radiation. Therefore, is important to conduct studies on radioactive levels that are generated in hospitals, as a result of the use of medical equipment. To determine levels of exposure speed of a radioactive facility there are different methods, including the radiation detector and computational method. This thesis uses the computational method. With the program MCNP5 was determined the speed of the radiation exposure in the radiotherapy room of Cancer Center of ABC Hospital in Mexico City. In the application of computational method, first the thicknesses of the shields were calculated, using variables as: 1) distance from the shield to the source; 2) desired weekly equivalent dose; 3) weekly total dose equivalent emitted by the equipment; 4) occupation and use factors. Once obtained thicknesses, we proceeded to model the bunker using the mentioned program. The program uses the Monte Carlo code to probabilistic ally determine the phenomena of interaction of radiation with the shield, which will be held during the X-ray emission from the linear accelerator. The results of computational analysis were compared with those obtained experimentally with the detection method, for which was required the use of a Geiger-Muller counter and the linear accelerator was programmed with an energy of 19 MV with 500 units monitor positioning the detector in the corresponding boundary. (Author)

Accelerator Based Neutron Beams for Neutron Capture Therapy

International Nuclear Information System (INIS)

Yanch, Jacquelyn C.

2003-01-01

The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

An assessment of effective dose to staff in external beam radiotherapy

International Nuclear Information System (INIS)

Rawlings, D.J.; Nicholson, L.

1997-01-01

Radiation safety in external beam radiotherapy is governed by national legislation. Annual doses recorded by radiographers and others associated with external beam radiotherapy are typically much lower than the relevant dose limit. However, it is possible that larger doses might be received as a result of an accidental irradiation. In the event of a significant exposure resulting in a dose at or near a relevant dose limit, an accurate conversion has to be made from the dose meter reading to the limiting quantity. A method was devised to demonstrate ratios of effective dose to personal dose equivalent which might be anticipated in the even of an individual other than the patient being irradiated within a radiotherapy treatment room consisting of a linear accelerator. The variation of ratios obtained under different conditions is discussed. (author)

A Miracle That Accelerates Operating Room Functionality: Sugammadex

Directory of Open Access Journals (Sweden)

Erdal Dogan

2014-01-01

Full Text Available Background. Sugammadex offers a good alternative to the conventional decurarisation process currently performed with cholinesterase inhibitors. Sugammadex, which was developed specifically for the aminosteroid-structured rocuronium and vecuronium neuromuscular blockers, is a modified cyclodextrin made up of 8 glucose monomers arranged in a cylindrical shape. Methods. In this study, the goal was to investigate the efficacy of sugammadex. Sugammadex was used when there was insufficient decurarisation following neostigmine. This study was performed on 14 patients who experienced insufficient decurarisation (TOF <0.9 with neostigmine after general anaesthesia in the operating rooms of a university and a state hospital between June, 2012, and January, 2014. A dose of 2 mg/kg of sugammadex was administered. Results. Time elapsed until sugammadex administration following neostigmine 37 ± 6 min, following sugammadex it took 2.1 ± 0.9 min to reach TOF ≥ 0.9, and the extubation time was 3.2 ± 1.4 min. No statistically significant differences were detected in the hemodynamic parameters before and after sugammadex application. From the time of administration of sugammadex to the second postoperative hour, no side effects or complications occurred. None of the patients experienced acute respiratory failure or residual block during this time period. Conclusion. Sugammadex was successfully used to reverse rocuronium-induced neuromuscular block in patients where neostigmine was insufficient.

Re-Shielding of Cobalt-60 Teletherapy Rooms for Tomotherapy and Conventional Linear Accelerators using Monte Carlo Simulations

Science.gov (United States)

Çeçen, Yiğit; Yazgan, Çağrı

2017-09-01

Purpose. Nearly all Cobalt-60 teletherapy machines were removed around the world during the last two decades. The remaining ones are being used for experimental purposes. However, the rooms of these teletherapy machines are valuable because of lack of space in radiotherapy clinics. In order to place a new technology treatment machine in one of these rooms, one should re-shield the room since it was designed only for 1.25 MeV gamma beams on average. Mostly, the vendor of the new machine constructs the new shielding of the room using their experience. However, every radiotherapy room has different surrounding work areas and it would be wise to shield the room considering these special conditions. Also, the shield design goal of the clinic may be much lower than the International Atomic Energy Agency (IAEA) or the local association accepts. The study shows re-shielding of a Cobalt-60 room, specific to the clinic, using Monte Carlo simulations. Materials & Methods: First, a 6 MV Tomotherapy machine, then a 10 MV conventional linear accelerator (LINAC) was placed inside the Cobalt-60 teletherapy room. The photon flux outside the room was simulated using Monte Carlo N-Particle (MCNP6.1) code before and after re-shielding. For the Tomotherapy simulation, flux distributions around the machine were obtained from the vendor and implemented as the source of the model. The LINAC model was more generic with the 10 MeV electron source, the tungsten target, first and secondary collimators. The aim of the model was to obtain the maximum (40x40 cm2) open field at the isocenter. Two different simulations were carried out for gantry angles 90o and 270o. The LINAC was placed in the room such that the primary walls were A' (Gantry 270o) and C' (Gantry 90o) (figure 1). The second part of the study was to model the re-shielding of the room for Tomotherapy and for the conventional LINAC, separately. The aim was to investigate the recommended shielding by the vendors. Left side of the room

Technical Note: A proposal of air ventilation system design criteria for a clinical room in a heavy-ion medical facility.

Science.gov (United States)

Kum, Oyeon

2018-04-16

An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. Optimized design criteria of air ventilation system for a clinical room in 430 MeV/u carbon ion beam medical accelerator facility was performed by using a combination of MCNPX2.7.0 and CINDER'90 codes. Effective dose rate and its accumulated effective dose by inhalation and residual gamma were calculated for a normal treatment scenario (2 min irradiation for one fraction) as a function of decay time. Natural doses around the site were measured before construction and used as reference data. With no air ventilation system, the maximum effective dose rate was about 3 μSv/h (total dose of 90 mSv/y) and minimum 0.2 μSv/h (total dose of 6 mSv/y), which are over the legal limits for medical staff and for the general public. Although inhalation dose contribution was relatively small, it was considered seriously because of its long-lasting effects in the body. The integrated dose per year was 1.8 mSv/y in the radiation-free area with the 20-min rate of air ventilation system. An optimal air ventilation rate of 20 min is proposed for a clinical room, which also agrees with the best mechanical design value. © 2018 American Association of Physicists in Medicine.

Environmental equivalent dose due to radiation dispersed by the patient body in treatments with tomotherapy; Dosis equivalente ambiental debida a la radiacion dispersada por el cuerpo del paciente en tratamientos con tomoterapia

Energy Technology Data Exchange (ETDEWEB)

Esparza H, A.; Luna S, K. C.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Reyes R, E., E-mail: ange.es.he55@gmail.com [Universidad de Guanajuato, Division de Ciencias e Ingenieria, 37150 Leon, Guanajuato (Mexico)

2017-09-15

One of the important parameters of the design and evaluation of the bunker of a linear accelerator for radiotherapy is the dose at the point to be protected behind the barriers of the treatment room. In the case of primary barriers this dose is due to direct radiation and in the case of secondary barriers is the dose due to radiation that leaks from the head and the dose due to radiation scattered by the body of the patient. In Zacatecas the bunker in the oncology ward was designed for a linear accelerator of 18 MV, but an accelerator of the latest technology was installed, which is a linear accelerator of 6 MV for tomotherapy that has a better control of the applied dose. In order to determine the dose due to the scattered radiation that reaches the internal surfaces of the barriers of the room, thermoluminescent dosimeters (TLDs) of type 100 were used, which were placed on three occasions, in 9 points inside the bunker for periods of 7 days. During these periods, patients were routinely treated and treated for different tumors using different procedures. At each measurement point, 4 dosimeters were placed. The readings of the TLDs were used to calculate the environmental equivalent dose that was normalized to the applied dose. The highest doses were found on the surface of the accelerator and did not show symmetry, in the primary barriers the same doses were found and in the labyrinth the dose due to scattered radiation is influenced by the Compton dispersion that the photons scattered on the wall of the labyrinth background. (Author)

Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator

International Nuclear Information System (INIS)

Lundh, O.; Rechatin, C.; Faure, J.; Ben-Ismaïl, A.; Lim, J.; De Wagter, C.; De Neve, W.; Malka, V.

2012-01-01

Purpose: To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. Methods: In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. Results: It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. Conclusions: The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research.

Radiation therapy with laser-driven accelerated particle beams: physical dosimetry and spatial dose distribution

Energy Technology Data Exchange (ETDEWEB)

Reinhardt, Sabine; Assmann, Walter [Ludwig-Maximilians Universitaet Muenchen (Germany); Kneschaurek, Peter; Wilkens, Jan [MRI, Technische Universitaet Muenchen (Germany)

2011-07-01

One of the main goals of the Munich Centre for Advanced Photonics (MAP) is the application of laser driven accelerated (LDA) particle beams for radiation therapy. Due to the unique acceleration process ultrashort particle pulses of high intensity (> 10{sup 7} particles /cm{sup 2}/ns) are generated, which makes online detection an ambitious task. So far, state of the art detection of laser accelerated ion pulses are non-electronic detectors like radiochromic films (RCF), imaging plates (IP) or nuclear track detectors (e.g. CR39). All these kind of detectors are offline detectors requiring several hours of processing time. For this reason they are not qualified for an application in radiation therapy where quantitative real time detection of the beam is an essential prerequisite. Therefore we are investigating pixel detectors for real time monitoring of LDA particle pulses. First tests of commercially available systems with 8-20 MeV protons are presented. For radiobiological experiments second generation Gafchromic films (EBT2) have been calibrated with protons of 12 and 20 MeV for a dose range of 0.3-10 Gy. Dose verification in proton irradiation of subcutaneous tumours in mice was successfully accomplished using these films.

A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

Science.gov (United States)

Nwankwo, Obioma; Glatting, Gerhard; Wenz, Frederik; Fleckenstein, Jens

2017-01-01

To introduce a new method of deriving a virtual source model (VSM) of a linear accelerator photon beam from a phase space file (PSF) for Monte Carlo (MC) dose calculation. A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs) for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC) between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses. The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate) for the evaluated fields. A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

A single-source photon source model of a linear accelerator for Monte Carlo dose calculation.

Directory of Open Access Journals (Sweden)

Obioma Nwankwo

Full Text Available To introduce a new method of deriving a virtual source model (VSM of a linear accelerator photon beam from a phase space file (PSF for Monte Carlo (MC dose calculation.A PSF of a 6 MV photon beam was generated by simulating the interactions of primary electrons with the relevant geometries of a Synergy linear accelerator (Elekta AB, Stockholm, Sweden and recording the particles that reach a plane 16 cm downstream the electron source. Probability distribution functions (PDFs for particle positions and energies were derived from the analysis of the PSF. These PDFs were implemented in the VSM using inverse transform sampling. To model particle directions, the phase space plane was divided into a regular square grid. Each element of the grid corresponds to an area of 1 mm2 in the phase space plane. The average direction cosines, Pearson correlation coefficient (PCC between photon energies and their direction cosines, as well as the PCC between the direction cosines were calculated for each grid element. Weighted polynomial surfaces were then fitted to these 2D data. The weights are used to correct for heteroscedasticity across the phase space bins. The directions of the particles created by the VSM were calculated from these fitted functions. The VSM was validated against the PSF by comparing the doses calculated by the two methods for different square field sizes. The comparisons were performed with profile and gamma analyses.The doses calculated with the PSF and VSM agree to within 3% /1 mm (>95% pixel pass rate for the evaluated fields.A new method of deriving a virtual photon source model of a linear accelerator from a PSF file for MC dose calculation was developed. Validation results show that the doses calculated with the VSM and the PSF agree to within 3% /1 mm.

Concept for calculating dose rates from activated groundwater at accelerator sites

CERN Document Server

Prolingheuer, N; Vanderborght, J; Schlögl, B; Nabbi, R; Moormann, R

Licensing of particle accelerators requires the proof that the groundwater outside of the site will not be significantly contaminated by activation products formed below accelerator and target. In order to reduce the effort for this proof, a site independent simplified but conservative method is under development. The conventional approach for calculation of activation of soil and groundwater is shortly described on example of a site close to Forschungszentrum Juelich, Germany. Additionally an updated overview of a data library for partition coefficients for relevant nuclides transported in the aquifer at the site is presented. The approximate model for transport of nuclides with ground water including exemplary results on nuclide concentrations outside of the site boundary and of resulting effective doses is described. Further applications and developments are finally outlined.

SU-E-T-270: Optimized Shielding Calculations for Medical Linear Accelerators (LINACs).

Science.gov (United States)

Muhammad, W; Lee, S; Hussain, A

2012-06-01

The purpose of radiation shielding is to reduce the effective equivalent dose from a medical linear accelerator (LINAC) to a point outside the room to a level determined by individual state/international regulations. The study was performed to design LINAC's room for newly planned radiotherapy centers. Optimized shielding calculations were performed for LINACs having maximum photon energy of 20 MV based on NCRP 151. The maximum permissible dose limits were kept 0.04 mSv/week and 0.002 mSv/week for controlled and uncontrolled areas respectively by following ALARA principle. The planned LINAC's room was compared to the already constructed (non-optimized) LINAC's room to evaluate the shielding costs and the other facilities those are directly related to the room design. In the evaluation process it was noted that the non-optimized room size (i.e., 610 × 610 cm 2 or 20 feet × 20 feet) is not suitable for total body irradiation (TBI) although the machine installed inside was having not only the facility of TBI but the license was acquired. By keeping this point in view, the optimized INAC's room size was kept 762 × 762 cm 2. Although, the area of the optimized rooms was greater than the non-planned room (i.e., 762 × 762 cm 2 instead of 610 × 610 cm 2), the shielding cost for the optimized LINAC's rooms was reduced by 15%. When optimized shielding calculations were re-performed for non-optimized shielding room (i.e., keeping room size, occupancy factors, workload etc. same), it was found that the shielding cost may be lower to 41 %. In conclusion, non- optimized LINAC's room can not only put extra financial burden on the hospital but also can cause of some serious issues related to providing health care facilities for patients. © 2012 American Association of Physicists in Medicine.

Incident report and estimates of personnel exposure for a staff present in maze corridor of linac room while radiation beam on

International Nuclear Information System (INIS)

Ravichandran, R.; Davis, C.A.; Ghamrawy, Kamal El; Arunkumar, L.S.

2007-01-01

The radiation safety features of high energy linear accelerator installations include primary and secondary barriers made of concrete (radiation bunkers), provision of maze wall for eliminating first scatter reaching the entrance door, locating room entrance perpendicular to maze corridor to reduce neutron dose. In addition, special motorized doors with lead lining and paraffin blocks, electrically interlocked to beam on-off system is provided for radiation safety. A radiation incident took place involving presence of a staff inside the Clinac 2300 CD room in September 2006 has been described

Comparison of measured with calculated dose distribution from a 120-MeV electron beam from a laser-plasma accelerator.

Science.gov (United States)

Lundh, O; Rechatin, C; Faure, J; Ben-Ismaïl, A; Lim, J; De Wagter, C; De Neve, W; Malka, V

2012-06-01

To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research. © 2012 American Association of Physicists in Medicine.

A dose-response curve for biodosimetry from a 6 MV electron linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Lemos-Pinto, M.M.P.; Cadena, M.; Santos, N.; Fernandes, T.S.; Borges, E.; Amaral, A., E-mail: marcelazoo@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

2015-10-15

Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates. (author)

A dose-response curve for biodosimetry from a 6 MV electron linear accelerator.

Science.gov (United States)

Lemos-Pinto, M M P; Cadena, M; Santos, N; Fernandes, T S; Borges, E; Amaral, A

2015-10-01

Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates.

Personnel hazards from medical electron accelerator photoneutrons

International Nuclear Information System (INIS)

Mcall, R.C.; Jenkins, T.M.; Shore, R.A.; LaRiviere, P.D.

1980-01-01

Medical electron accelerators operated in the photon mode produce significant amounts of photoneutrons at energies above 15 MeV. There can be definite radiation problems at doors of treatment rooms where operating consoles are often located. These problems are due in large part to inadequate maze design by physicists unaccustomed to shielding against neutrons. The radiation field at the door is an unusual combination of low energy neutrons, thermal neutrons and capture γ-rays from the concrete walls of the maze and the door itself. While this radiation field is dependent upon the actual construction details, these three components each contribute roughly one-third of the total dose equivalent. Reducing these high radiation levels presents a formidable problem. The neutrons can be absorbed by hydrogenous material which can be attached to the door, but the neutron capture γ-rays would require massive amounts of lead for the required attenuation. Both measurements and Monte Carlo calculations are presented to illustrate the problem. Some possible shielding solutions are presented for pre-existing treatment rooms, as well as design recommendations for new rooms. (H.K.)

Heavy ion medical accelerator, HIMAC

International Nuclear Information System (INIS)

Yamada, Satoru

1993-01-01

The heavy ion beam is undoutedly suitable for the cancer treatment. The supriority of the heavy ions over the conventional radiations including protons and neutrons comes mainly from physical characteristics of a heavy particle with multiple charges. A straggling angle due to a multiple Coulomb scattering process in a human body is small for heavy ions, and the small scattering angle results in a good dose localization in a transverse direction. An ionization ratio of the heavy ion beam makes a very sharp peak at the ends of their range. The height of the peak is higher for the heavier ions and shows excellent biomedical effects around Ne ions. In order to apply heavy ion beams to cancer treatment, Heavy Ion Medical Accelerator in Chiba (HIMAC) has been constructed at National Institute of Radiological Sciences. The accelerator complex consists of two ion sources, two successive linac tanks, a pair of synchrotron rings, a beam transport system and an irradiation system. An operation frequency is 100 MHz for two linacs, and the ion energy is 6.0 MeV/u at the output end of the linac. The other four experimental rooms are prepared for basic experiments. The synchrotron accelerates ions up to 800 MeV/u for a charge to mass ratio of 1/2. The long beam transport line provides two vertical beams in addition with two horizontal beams for the treatment. The three treatment rooms are prepared one of which is equipped with both horizontal and vertical beam lines. The whole facility will be open for all scientists who have interests in the heavy ion science as well as the biophysics. The conceptual design study of HIMAC started in 1984, and the construction of the accelerator complex was begun in March 1988. The beam acceleration tests of the injector system was successfully completed in March of this year, and tests of the whole system will be finished throughout this fyscal year. (author)

Medical heavy ion accelerator proposals

International Nuclear Information System (INIS)

Gough, R.A.

1985-05-01

For several decades, accelerators designed primarily for research in nuclear and high energy physics have been adapted for biomedical research including radiotherapeutic treatment of human diseases such as pituitary disorders, cancer, and more recently, arteriovascular malformations. The particles used in these treatments include pions, protons and heavier ions such as carbon, neon, silicon and argon. Maximum beam energies must be available to penetrate into an equivalent of about 30 cm of water, requiring treatment beams of 250 to 1000 MeV/nucleon. Certain special treatments of superficial melanoma, however, require that beam energies as low as 70 MeV/nucleon also be available. Intensities must be adequate to complete a 100 rad treatment fraction in about 1 minute. For most heavy ion treatments, this corresponds to 10 7 -10 9 ions/second at the patient. Because this research is best conducted in a dedicated, hospital-based facility, and because of the clinical need for ultra-high reliability, the construction of new and dedicated facilities has been proposed. Heavy ion accelerators can provide a variety of ions and energies, permitting treatment plans that exploit the properties of the ion best suited to each individual treatment, and that employ radioactive beams (such as 11 C and 19 Ne) to precisely confirm the dose localization. The favored technical approach in these proposals utilizes a conventional, strong-focusing synchrotron capable of fast switching between ions and energies, and servicing multiple treatment rooms. Specialized techniques for shaping the dose to conform to irregularly-shaped target volumes, while simultaneously sparing surrounding, healthy tissue and critical structures, are employed in each treatment room, together with the sophisticated dosimetry necessary for verification, monitoring, and patient safety. 3 refs., 8 figs

HDRMC, an accelerated Monte Carlo dose calculator for high dose rate brachytherapy with CT-compatible applicators

Energy Technology Data Exchange (ETDEWEB)

Chibani, Omar, E-mail: omar.chibani@fccc.edu; C-M Ma, Charlie [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)

2014-05-15

Purpose: To present a new accelerated Monte Carlo code for CT-based dose calculations in high dose rate (HDR) brachytherapy. The new code (HDRMC) accounts for both tissue and nontissue heterogeneities (applicator and contrast medium). Methods: HDRMC uses a fast ray-tracing technique and detailed physics algorithms to transport photons through a 3D mesh of voxels representing the patient anatomy with applicator and contrast medium included. A precalculated phase space file for the{sup 192}Ir source is used as source term. HDRM is calibrated to calculated absolute dose for real plans. A postprocessing technique is used to include the exact density and composition of nontissue heterogeneities in the 3D phantom. Dwell positions and angular orientations of the source are reconstructed using data from the treatment planning system (TPS). Structure contours are also imported from the TPS to recalculate dose-volume histograms. Results: HDRMC was first benchmarked against the MCNP5 code for a single source in homogenous water and for a loaded gynecologic applicator in water. The accuracy of the voxel-based applicator model used in HDRMC was also verified by comparing 3D dose distributions and dose-volume parameters obtained using 1-mm{sup 3} versus 2-mm{sup 3} phantom resolutions. HDRMC can calculate the 3D dose distribution for a typical HDR cervix case with 2-mm resolution in 5 min on a single CPU. Examples of heterogeneity effects for two clinical cases (cervix and esophagus) were demonstrated using HDRMC. The neglect of tissue heterogeneity for the esophageal case leads to the overestimate of CTV D90, CTV D100, and spinal cord maximum dose by 3.2%, 3.9%, and 3.6%, respectively. Conclusions: A fast Monte Carlo code for CT-based dose calculations which does not require a prebuilt applicator model is developed for those HDR brachytherapy treatments that use CT-compatible applicators. Tissue and nontissue heterogeneities should be taken into account in modern HDR

Effluent Monitoring System Design for the Proton Accelerator Research Center of PEFP

International Nuclear Information System (INIS)

Kim, Jun Yeon; Mun, Kyeong Jun; Cho, Jang Hyung; Jo, Jeong Hee

2010-01-01

Since host site host site was selected Gyeong-ju city in January, 2006. we need design revision of Proton Accelerator research center to reflect on host site characteristics and several conditions. Also the IAC recommended maximization of space utilization and construction cost saving. After GA(General Arrangement) is made a decision, it is necessary to evaluate the radiation analysis of every controlled area in the proton accelerator research center such as accelerator tunnel, Klystron gallery, beam experimental hall, target rooms and ion beam application building to keep dose rate below the ALARA(As Low As Reasonably achievable) objective. Our staff has reviewed and made a shielding design of them. In this paper, According to accelerator operation mode and access conditions based on radiation analysis and shielding design, we made the exhaust system configuration of controlled area in the proton accelerator research center. Also, we installed radiation monitor and set its alarm value for each radiation area

Influence of a transverse magnetic field on the dose deposited by a 6 MV linear accelerator

Directory of Open Access Journals (Sweden)

Richter Sebastian

2017-09-01

Full Text Available An integrated system of a linear accelerator and a magnetic resonance imaging (MRI device may provide real-time imaging during radiotherapy treatments. This work investigated changes affecting the dose deposition caused by a magnetic field (B-field transverse to the beam direction by means of Monte Carlo simulations. Two different phantoms were used: A water phantom (Ph1 and a water-air phantom (Ph2 with a 4-2-4 cm water-air-water cross section. Dose depositions were scored for B-field values of 0 T, 0.35 T, 0.5 T, 1.5 T, 3 T and 5 T. Beams were based on a precalculated photon spectrum taken from an earlier simulated Elekta 6 MV FFF accelerator. All lateral profiles in Ph1 showed a Lorentz force driven shift w.r.t. the B-field strength, presenting a steeper penumbra in the shift's direction. Depositions were shifted up to 0.3 cm for 5 T, showing a constant central axis plateau-dose or an increase by 2.3 % for small fields. Depth-dose curves in Ph1 showed a shift of the dose maximum towards the beam entrance direction for increasing B-field of up to 1.1 cm; the maximum dose was increased by 6.9 %. In Ph2, an asymmetric dose increase by up to 36.9 % was observed for 1.5 T at the water-air boundary, resulting from the electron return effect (ERE. In our scenario, B-field dependent dose shifts and local build-ups were observed, which consequently affect the resulting dose distribution and need to be considered in magnetic resonance guided radiotherapy treatment planning.

Remanent radiation fields around medical linear accelerators due to the induced radionuclides

International Nuclear Information System (INIS)

Sabol, J.; Khalifa, O.; Berka, Z.; Stankus, P.; Frencl, L.

1998-01-01

Radiation fields around two linear accelerators, Saturn 43 and a Saturn 2 Plus, installed at radiotherapy department is Prague, were measured and interpreted. The measurements included the determination of the dose equivalent rate resulting from photons emitted by induced radionuclides produced in reactions of high-energy photons with certain elements present in air and accelerator components as well as in the shielding and building materials in the treatment rooms, which are irradiated by high-energy X-rays, and due to radionuclides formed by capture of photoneutrons. While scattered photons and photoneutrons are only present during the accelerator operation, residual radioactivity creates a remanent radiation field persisting for some time after the instrument shutdown. The activity induced in the accessories is also an important source of exposure. (P.A.)

The effect of a paraffin screen on the neutron dose at the maze door of a 15 MV linear accelerator.

Science.gov (United States)

Krmar, M; Nikolić, D; Kuzmanović, A; Kuzmanović, Z; Ganezer, K

2013-08-01

The purpose of this study was to explore the effects of a paraffin screen located at various positions in the maze on the neutron dose equivalent at the maze door. The neutron dose equivalent was measured at the maze door of a room containing a 15 MV linear accelerator for x-ray therapy. Measurements were performed for several positions of the paraffin screen covering only 27.5% of the cross-sectional area of the maze. The neutron dose equivalent was also measured at all screen positions. Two simple models of the neutron source were considered in which the first assumed that the source was the cross-sectional area at the inner entrance of the maze, radiating neutrons in an isotropic manner. In the second model the reduction in the neutron dose equivalent at the maze door due to the paraffin screen was considered to be a function of the mean values of the neutron fluence and energy at the screen. The results of this study indicate that the equivalent dose at the maze door was reduced by a factor of 3 through the use of a paraffin screen that was placed inside the maze. It was also determined that the contributions to the dosage from areas that were not covered by the paraffin screen as viewed from the dosimeter, were 2.5 times higher than the contributions from the covered areas. This study also concluded that the contributions of the maze walls, ceiling, and floor to the total neutron dose equivalent were an order of magnitude lower than those from the surface at the far end of the maze. This study demonstrated that a paraffin screen could be used to reduce the neutron dose equivalent at the maze door by a factor of 3. This paper also found that the reduction of the neutron dose equivalent was a linear function of the area covered by the maze screen and that the decrease in the dose at the maze door could be modeled as an exponential function of the product φ·E at the screen.

Phase 1 Dose Escalation Study of Accelerated Radiation Therapy With Concurrent Chemotherapy for Locally Advanced Lung Cancer

Energy Technology Data Exchange (ETDEWEB)

Kelsey, Chris R., E-mail: christopher.kelsey@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Das, Shiva [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina (United States); Gu, Lin [Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina (United States); Dunphy, Frank R.; Ready, Neal E. [Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Durham, North Carolina (United States); Marks, Lawrence B. [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina (United States)

2015-12-01

Purpose: To determine the maximum tolerated dose of radiation therapy (RT) given in an accelerated fashion with concurrent chemotherapy using intensity modulated RT. Methods and Materials: Patients with locally advanced lung cancer (non-small cell and small cell) with good performance status and minimal weight loss received concurrent cisplatin and etoposide with RT. Intensity modulated RT with daily image guidance was used to facilitate esophageal avoidance and delivered using 6 fractions per week (twice daily on Fridays with a 6-hour interval). The dose was escalated from 58 Gy to a planned maximum dose of 74 Gy in 4 Gy increments in a standard 3 + 3 trial design. Dose-limiting toxicity (DLT) was defined as acute grade 3-5 nonhematologic toxicity attributed to RT. Results: A total of 24 patients were enrolled, filling all dose cohorts, all completing RT and chemotherapy as prescribed. Dose-limiting toxicity occurred in 1 patient at 58 Gy (grade 3 esophagitis) and 1 patient at 70 Gy (grade 3 esophageal fistula). Both patients with DLTs had large tumors (12 cm and 10 cm, respectively) adjacent to the esophagus. Three additional patients were enrolled at both dose cohorts without further DLT. In the final 74-Gy cohort, no DLTs were observed (0 of 6). Conclusions: Dose escalation and acceleration to 74 Gy with intensity modulated RT and concurrent chemotherapy was tolerable, with a low rate of grade ≥3 acute esophageal reactions.

Development of a computational model for the calculation of neutron dose equivalent in laminated primary barriers of radiotherapy rooms; Desenvolvimento de um modelo computacional para calculo do equivalente de dose de neutrons em barreiras primarias laminadas de salas de radioterapia

Energy Technology Data Exchange (ETDEWEB)

Rezende, Gabriel Fonseca da Silva

2015-06-01

Many radiotherapy centers acquire 15 and 18 MV linear accelerators to perform more effective treatments for deep tumors. However, the acquisition of these equipment must be accompanied by an additional care in shielding planning of the rooms that will house them. In cases where space is restricted, it is common to find primary barriers made of concrete and metal. The drawback of this type of barrier is the photoneutron emission when high energy photons (e.g. 15 and 18 MV spectra) interact with the metallic material of the barrier. The emission of these particles constitutes a problem of radiation protection inside and outside of radiotherapy rooms, which should be properly assessed. A recent work has shown that the current model underestimate the dose of neutrons outside the treatment rooms. In this work, a computational model for the aforementioned problem was created from Monte Carlo Simulations and Artificial Intelligence. The developed model was composed by three neural networks, each being formed of a pair of material and spectrum: Pb18, Pb15 and Fe18. In a direct comparison with the McGinley method, the Pb18 network exhibited the best responses for approximately 78% of the cases tested; the Pb15 network showed better results for 100% of the tested cases, while the Fe18 network produced better answers to 94% of the tested cases. Thus, the computational model composed by the three networks has shown more consistent results than McGinley method. (author)

Conversion coefficients for determination of dispersed photon dose during radiotherapy: NRUrad input code for MCNP.

Science.gov (United States)

Shahmohammadi Beni, Mehrdad; Ng, C Y P; Krstic, D; Nikezic, D; Yu, K N

2017-01-01

Radiotherapy is a common cancer treatment module, where a certain amount of dose will be delivered to the targeted organ. This is achieved usually by photons generated by linear accelerator units. However, radiation scattering within the patient's body and the surrounding environment will lead to dose dispersion to healthy tissues which are not targets of the primary radiation. Determination of the dispersed dose would be important for assessing the risk and biological consequences in different organs or tissues. In the present work, the concept of conversion coefficient (F) of the dispersed dose was developed, in which F = (Dd/Dt), where Dd was the dispersed dose in a non-targeted tissue and Dt is the absorbed dose in the targeted tissue. To quantify Dd and Dt, a comprehensive model was developed using the Monte Carlo N-Particle (MCNP) package to simulate the linear accelerator head, the human phantom, the treatment couch and the radiotherapy treatment room. The present work also demonstrated the feasibility and power of parallel computing through the use of the Message Passing Interface (MPI) version of MCNP5.

A virtual-accelerator-based verification of a Monte Carlo dose calculation algorithm for electron beam treatment planning in homogeneous phantoms

International Nuclear Information System (INIS)

Wieslander, Elinore; Knoeoes, Tommy

2006-01-01

By introducing Monte Carlo (MC) techniques to the verification procedure of dose calculation algorithms in treatment planning systems (TPSs), problems associated with conventional measurements can be avoided and properties that are considered unmeasurable can be studied. The aim of the study is to implement a virtual accelerator, based on MC simulations, to evaluate the performance of a dose calculation algorithm for electron beams in a commercial TPS. The TPS algorithm is MC based and the virtual accelerator is used to study the accuracy of the algorithm in water phantoms. The basic test of the implementation of the virtual accelerator is successful for 6 and 12 MeV (γ < 1.0, 0.02 Gy/2 mm). For 18 MeV, there are problems in the profile data for some of the applicators, where the TPS underestimates the dose. For fields equipped with patient-specific inserts, the agreement is generally good. The exception is 6 MeV where there are slightly larger deviations. The concept of the virtual accelerator is shown to be feasible and has the potential to be a powerful tool for vendors and users

Neutron equivalent dose rates at the surroundings of the electron linear accelerator operated by the university of Sao Paulo - Physics institute

International Nuclear Information System (INIS)

Yanagihara, L.S.

1984-01-01

For the determination of the neutron dose rates at the surroundings of an electron linear accelerators it is necessary the knowledge of the neutron spectrum or its mean energy, because the conversion factor of the flux in equivalent dose rates, is strongly dependent on the neutron energy. Taking this fact into consideration, equivalent dose rates were determined in the three representative sites of the IF/USP Linear Electron Accelerator. Also, due to the radiation field be pulsed, a theoretical and experimental study has been realized to evaluate the effect produced by the variation of the field on the detector. (author)

Photon dose evaluation at the entrance of radiotherapy bunkers without maze

International Nuclear Information System (INIS)

Facure, Alessandro; Salata, Camila

2017-01-01

Radiation protection has become an important field of study, as the use of ionizing radiation for diagnosis and therapy increased along the years. According to the ALARA principles, shielding is one of the most efficient ways to minimize radiation exposure. Linear accelerators for radiotherapy treatment can lead to a considerable risk due to radiation for public and workers if proper shielding is not calculated. Mazeless rooms for LINACS are becoming more usual, as they need less space to be constructed, but, on the other hand they are more expensive. The doors of those kinds of rooms are an important point, as they will have to be thicker in mazelles room to proper shield the radiation. The NCRP 151 lays out the general considerations for the shielding calculation of standard rooms, with mazes, but there are no specific recommendations for mazeless rooms on literature. The work herein presented evaluated the absorbed dose in a room model without maze, which will be constructed soon in Brazil. The applicant calculated the thickness of the door as if it was a room with maze, and the authors used computational simulation wit MCNP code to simulate the same room, and calculated the door thickness as if it was a secondary barrier. The dose limit considered was for public occupation, 1 mSv/sem, and the energy beam was of 6 MeV. The simulated results showed that the applicant calculation thickness for the door was underestimated in 88%. The obtained results are important to establish a better methodology for shielding calculation of mazeless radiotherapy rooms that are becoming more common in Brazil. (author)

Photon dose evaluation at the entrance of radiotherapy bunkers without maze

Energy Technology Data Exchange (ETDEWEB)

Facure, Alessandro; Salata, Camila, E-mail: facure@cnen.gov.br, E-mail: camila.salata@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de janeiro, RJ (Brazil)

2017-07-01

Radiation protection has become an important field of study, as the use of ionizing radiation for diagnosis and therapy increased along the years. According to the ALARA principles, shielding is one of the most efficient ways to minimize radiation exposure. Linear accelerators for radiotherapy treatment can lead to a considerable risk due to radiation for public and workers if proper shielding is not calculated. Mazeless rooms for LINACS are becoming more usual, as they need less space to be constructed, but, on the other hand they are more expensive. The doors of those kinds of rooms are an important point, as they will have to be thicker in mazelles room to proper shield the radiation. The NCRP 151 lays out the general considerations for the shielding calculation of standard rooms, with mazes, but there are no specific recommendations for mazeless rooms on literature. The work herein presented evaluated the absorbed dose in a room model without maze, which will be constructed soon in Brazil. The applicant calculated the thickness of the door as if it was a room with maze, and the authors used computational simulation wit MCNP code to simulate the same room, and calculated the door thickness as if it was a secondary barrier. The dose limit considered was for public occupation, 1 mSv/sem, and the energy beam was of 6 MeV. The simulated results showed that the applicant calculation thickness for the door was underestimated in 88%. The obtained results are important to establish a better methodology for shielding calculation of mazeless radiotherapy rooms that are becoming more common in Brazil. (author)

Dedicated medical ion accelerator design study. Final report

International Nuclear Information System (INIS)

1977-12-01

Results and conclusions are reported from a design study for a dedicated medical accelerator. Basing efforts on the current consensus regarding medical requirements, the resulting demands on accelerator and beam delivery systems were analyzed, and existing accelerator technology was reviewed to evaluate the feasibility of meeting these demands. This general analysis was augmented and verified by preparing detailed preliminary designs for sources of therapeutic beams of neutrons, protons and heavy ions. The study indicates that circular accelerators are the most desirable and economical solutions for such sources. Synchrotrons are clearly superior for beams of helium and heavier ions, while synchrotrons and cyclotrons seem equally well suited for protons although they have different strengths and weaknesses. Advanced techniques of beam delivery are of utmost importance in fully utilizing the advantages of particle beams. Several issues are invloved here. First, multi-treatment room arrangements are essential for making optimal use of the high dose rate capabilities of ion accelerators. The design of corresponding beam switching systems, the principles of which are already developed for physics experimental areas, pose no problems. Second, isocentric beam delivery substantially enhances flexibility of dose delivery. After several designs for such devices were completed, it was concluded that high field magnets are necessary to keep size, bulk and cost acceptable. Third, and most important, is the generation of large, homogeneous radiation fields. This is presently accomplished with the aid of scattering foils, occluding rings, collimators, ridge filters, and boluses. A novel approach, three-dimensional beam scanning, was developed here, and the most demanding components of such a system (fast-scanning magnet and power supply) were built and tested

Evaluation of time-accelerated irradiation method of elastomer by modulus-ultimate elongation profile

International Nuclear Information System (INIS)

Ito, Masayuki; Oka, Toshitaka; Hama, Yosimasa

2009-01-01

'Generalized modulus-ultimate elongation profile' was induced from the relationship between the modulus and the ultimate elongation of an elastomer that was quantitatively added crosslinking and scission. This profile can be used to evaluate the time-accelerated irradiation methods of ethylene-propylene-diene elastomer. The irradiation under low dose rate (0.33 kGy/h) at room temperature was the reference condition. The short-time irradiation condition was 4.2 kGy/h in 0.5 MPa oxygen at room temperature and 5.0 kGy/h in air at 70 o C. The former tended to bring about the higher ratio of scission than the reference condition; the latter tended to bring about the higher ratio of crosslinking.

Absorbed dose to mice in prolonged irradiation by low-dose rate ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Shiragai, Akihiro [National Inst. of Radiological Sciences, Chiba (Japan); Saitou, Mikio; Kudo, Iwao [and others

2000-07-01

In this paper, the dose absorbed by mice was evaluated as a preliminary study of the late effects of prolonged continuous irradiation of mice with low-dose rate ionizing radiation. Eight-week-old male and female SPF C3H/HeN mice in three irradiation rooms were exposed to irradiation at 8000, 400, and 20 mGy, respectively, using a {sup 137}Cs {gamma}-source. Nine racks were arranged in a circle approximately 2.5 m from the source in each room, and 10 cages were arranged on the 4 shelves of each rack. Dose distributions, such as in air at the source level, in the three rooms were estimated by using ionization chambers, and the absorbed dose distributions in the room and relative dose distributions in the cages in relation to the distance of the cage center were examined. The mean abdomen doses of the mice measured by TLD were compared with the absorbed doses in the cages. The absorbed dose distributions showed not only inverse-inverse-square-law behavior with distance from the source, but geometric symmetry in every room. The inherent scattering and absorption in each room are responsible for such behavior and asymmetry. Comparison of relative dose distributions revealed cage positions that are not suitable for experiments with high precision doses, but all positions can be used for prolonged continuous irradiation experiments if the position of the cages is rotated regularly. The mean abdomen doses of the mice were similar in each cage. The mean abdomen doses of the mice and the absorbed doses in a cage were almost the same in all cages. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about {+-}12% for 8000 mGy group, 17% for 400 mGy group, and 35% for 20 mGy group. (K.H.)

Technology and applications of advanced accelerator concepts

CERN Document Server

Chou, Weiren

2016-01-01

Since its invention in the 1920s, particle accelerators have made tremendous progress in accelerator science, technology and applications. However, the fundamental acceleration principle, namely, to apply an external radiofrequency (RF) electric field to accelerate charged particles, remains unchanged. As this method (either room temperature RF or superconducting RF) is approaching its intrinsic limitation in acceleration gradient (measured in MeV/m), it becomes apparent that new methods with much higher acceleration gradient (measured in GeV/m) must be found for future very high energy accelerators as well as future compact (table-top or room-size) accelerators. This volume introduces a number of advanced accelerator concepts (AAC) — their principles, technologies and potential applications. For the time being, none of them stands out as a definitive direction in which to go. But these novel ideas are in hot pursuit and look promising. Furthermore, some AAC requires a high power laser system. This has the ...

Radiation protection in the operating room

International Nuclear Information System (INIS)

Kunz, B.; Stargardt, A.

1978-01-01

On the basis of legally provided area dose measurements and time records of fluoroscopic examinations during the operation, radiation doses to medical personnel and patients are evaluated. Adequate radiation protection measures and a careful behaviour in the operating room keep the radiation exposure to the personnel below the maximum permissible exposure. Taking into account the continuous personnel radiation monitoring and medical supervision, radiation hazards in the operating room can be considered low

Determination of radon in housing rooms

International Nuclear Information System (INIS)

Steger, F.; Sorantin, H.; Kozuh-Schneeberger, J.; Lovranich, E.; Khademi, B.

1988-03-01

Radon concentration in 171 apartments with 503 rooms in and around Vienna was measured by a passive measuring system. Polycarbonate foils were exposed during 3 months; the nuclear tracks were visualized by electro-chemical method and evaluated. In housing- and sleeping rooms the mean concentration was 1,03 pCi/l, in cellars 2,15 pCi/l. The equivalent dosis, with 1,03 pCi/l was estimated to 90 mrem/a. At the same time the external radiation dose in the same rooms was measured by TL dosimeters and the dose estimated is again 90 mrem/a. 34 refs., 16 figs., 4 tabs. (qui)

Analysis of the spatial dose according to the type of radiation source used in multi-bed hospital room

Energy Technology Data Exchange (ETDEWEB)

Jang, Dong Gun [Dept. of Nuclear Medicine, Dongnam Institute of Radiological and Medical Sciences Cancer center, Busan (Korea, Republic of); Kim, Jung Hoon [Dept. of Radiological Science, College of Health Sciences, Catholic University of Pusan, Busan (Korea, Republic of); Park, Eun Tae [Dept. of Radiation Oncology, Busan Paik Hospital, Inje University, Busan (Korea, Republic of)

2017-09-15

Medical radiation offers significant benefits in diagnosing and treating patients, but it also generates unnecessary radiation exposure to those nearby. Accordingly, the objective of the present study was to analyze spatial dose rate according to types of radiation source term in multi-bed hospital rooms occupied by patients and general public. MCNPX was used for geometric simulation of multi-bed hospital rooms and radiation source terms, while the radiation source terms were established as whole body bone scan patients and imaging using a portable X-ray generator. The results of simulation on whole body bone scan patients showed 3.46 μSv/hr to another patient position, while experimental results on imaging using a portable X-ray generator showed 1.47 × 10{sup -8} μSv/irradiation to another patient position in chest imaging and 2.97 × 10{sup -8} μSv/irradiation to another patient position in abdomen imaging. Multi-bed hospital room, unnecessary radiation generated in the surrounding patients, while legal regulations and systematic measures are needed for radiation exposure in multi-bed hospital rooms that are currently lacking in Korea.

The final technical report of the CRADA, 'Medical Accelerator Technology'

International Nuclear Information System (INIS)

Chu, W.T.; Rawls, J.M.

2000-01-01

Under this CRADA, Berkeley Lab and the industry partner, General Atomics (GA), have cooperatively developed hadron therapy technologies for commercialization. Specifically, Berkeley Lab and GA jointly developed beam transport systems to bring the extracted protons from the accelerator to the treatment rooms, rotating gantries to aim the treatment beams precisely into patients from any angle, and patient positioners to align the patient accurately relative to the treatment beams. We have also jointly developed a patient treatment delivery system that controls the radiation doses in the patient, and hardware to improve the accelerator performances, including a radio-frequency ion source and its low-energy beam transport (LEBT) system. This project facilitated the commercialization of the DOE-developed technologies in hadron therapy by the private sector in order to improve the quality of life of the nation

SU-E-T-36: A GPU-Accelerated Monte-Carlo Dose Calculation Platform and Its Application Toward Validating a ViewRay Beam Model

Energy Technology Data Exchange (ETDEWEB)

Wang, Y; Mazur, T; Green, O; Hu, Y; Wooten, H; Yang, D; Zhao, T; Mutic, S; Li, H [Washington University School of Medicine, St. Louis, MO (United States)

2015-06-15

Purpose: To build a fast, accurate and easily-deployable research platform for Monte-Carlo dose calculations. We port the dose calculation engine PENELOPE to C++, and accelerate calculations using GPU acceleration. Simulations of a Co-60 beam model provided by ViewRay demonstrate the capabilities of the platform. Methods: We built software that incorporates a beam model interface, CT-phantom model, GPU-accelerated PENELOPE engine, and GUI front-end. We rewrote the PENELOPE kernel in C++ (from Fortran) and accelerated the code on a GPU. We seamlessly integrated a Co-60 beam model (obtained from ViewRay) into our platform. Simulations of various field sizes and SSDs using a homogeneous water phantom generated PDDs, dose profiles, and output factors that were compared to experiment data. Results: With GPU acceleration using a dated graphics card (Nvidia Tesla C2050), a highly accurate simulation – including 100*100*100 grid, 3×3×3 mm3 voxels, <1% uncertainty, and 4.2×4.2 cm2 field size – runs 24 times faster (20 minutes versus 8 hours) than when parallelizing on 8 threads across a new CPU (Intel i7-4770). Simulated PDDs, profiles and output ratios for the commercial system agree well with experiment data measured using radiographic film or ionization chamber. Based on our analysis, this beam model is precise enough for general applications. Conclusions: Using a beam model for a Co-60 system provided by ViewRay, we evaluate a dose calculation platform that we developed. Comparison to measurements demonstrates the promise of our software for use as a research platform for dose calculations, with applications including quality assurance and treatment plan verification.

SU-E-T-36: A GPU-Accelerated Monte-Carlo Dose Calculation Platform and Its Application Toward Validating a ViewRay Beam Model

International Nuclear Information System (INIS)

Wang, Y; Mazur, T; Green, O; Hu, Y; Wooten, H; Yang, D; Zhao, T; Mutic, S; Li, H

2015-01-01

Purpose: To build a fast, accurate and easily-deployable research platform for Monte-Carlo dose calculations. We port the dose calculation engine PENELOPE to C++, and accelerate calculations using GPU acceleration. Simulations of a Co-60 beam model provided by ViewRay demonstrate the capabilities of the platform. Methods: We built software that incorporates a beam model interface, CT-phantom model, GPU-accelerated PENELOPE engine, and GUI front-end. We rewrote the PENELOPE kernel in C++ (from Fortran) and accelerated the code on a GPU. We seamlessly integrated a Co-60 beam model (obtained from ViewRay) into our platform. Simulations of various field sizes and SSDs using a homogeneous water phantom generated PDDs, dose profiles, and output factors that were compared to experiment data. Results: With GPU acceleration using a dated graphics card (Nvidia Tesla C2050), a highly accurate simulation – including 100*100*100 grid, 3×3×3 mm3 voxels, <1% uncertainty, and 4.2×4.2 cm2 field size – runs 24 times faster (20 minutes versus 8 hours) than when parallelizing on 8 threads across a new CPU (Intel i7-4770). Simulated PDDs, profiles and output ratios for the commercial system agree well with experiment data measured using radiographic film or ionization chamber. Based on our analysis, this beam model is precise enough for general applications. Conclusions: Using a beam model for a Co-60 system provided by ViewRay, we evaluate a dose calculation platform that we developed. Comparison to measurements demonstrates the promise of our software for use as a research platform for dose calculations, with applications including quality assurance and treatment plan verification

TU-F-CAMPUS-T-01: Dose and Energy Spectra From Neutron Induced Radioactivity in Medical Linear Accelerators Following High Energy Total Body Irradiation

International Nuclear Information System (INIS)

Keehan, S; Taylor, M; Franich, R; Smith, R; Dunn, L; Kron, T

2015-01-01

Purpose: To assess the risk posed by neutron induced activation of components in medical linear accelerators (linacs) following the delivery of high monitor unit 18 MV photon beams such as used in TBI. Methods: Gamma spectroscopy was used to identify radioisotopes produced in components of a Varian 21EX and an Elekta Synergy following delivery of photon beams. Dose and risk estimates for TBI were assessed using dose deliveries from an actual patient treatment. A 1 litre spherical ion chamber (PTW, Germany) has been used to measure the dose at the beam exit window and at the total body irradiation (TBI) treatment couch following large and small field beams with long beam-on times. Measurements were also made outside of the closed jaws to quantify the benefit of the attenuation provided by the jaws. Results: The radioisotopes produced in the linac head have been identified as 187 W, 56 Mn, 24 Na and 28 Al, which have half-lives from between 2.3 min to 24 hours. The dose at the beam exit window following an 18 MV 2197 MU TBI beam delivery was 12.6 µSv in ten minutes. The dose rate at the TBI treatment couch 4.8 m away is a factor of ten lower. For a typical TBI delivered in six fractions each consisting of four beams and an annual patient load of 24, the annual dose estimate for a staff member at the treatment couch for ten minutes is 750 µSv. This can be further reduced by a factor of about twelve if the jaws are closed before entering the room, resulting in a dose estimate of 65 µSv. Conclusion: The dose resulting from the activation products for a representative TBI workload at our clinic of 24 patients per year is 750 µSv, which can be further reduced to 65 µSv by closing the jaws

Continuity of Accelerator Operations during an Extended Pandemic

International Nuclear Information System (INIS)

Noel Okay

2010-01-01

The Operations group for the Continuous Electron Accelerator Facility in Newport News Virginia has developed a Continuity of Operations plan for pandemic conditions when high absenteeism may impact accelerator control room operations. Protocols to address both the potential spread of illnesses in the control room environment as well as maintaining minimum staffing requirements for contiguous accelerator operation will be presented. During acute pandemic conditions local government restrictions may prevent continued operations but during extended periods of high absenteeism accelerator operations can continue when some added precautionary measures and staffing adjustments are made in the way business is done.

Occupational dosimetry in real time hemodynamic rooms. utility of the system Dose-aware as a training tool

International Nuclear Information System (INIS)

Pinto Monedero, M.; Rodriguez Cobo, C.; Pifarre Martinez, X.; Ruiz Martin, J.; Barros Candelero, J. M.; Goicolea Ruigomez, J.; Diaz Blaires, G.; Garcia Lunar

2014-01-01

This paper presents the results from a study in a real time dosimetry system used in the catheter laboratory room of our center. The objective was to know the occupational doses per procedure, on the one hand, and, on the other hand, to evaluate its utility as a learning tool for radiation protection purposes with the simultaneous video recording of the interventions. 83 diagnostic and therapeutic procedures were analyzed, and an average dose per procedure of 0,37 μSv and 0,10 μSv for the main cardiologist and nurse were obtained, respectively. 36 of these interventions were also recorded and the images were synchronized with the dosimetric information stored and the dosimetry system. The findings were presented to the interventional cardiology team in a learning session. They showed a high level of satisfaction with this new method of optimizing the occupational doses through a customized learning session. (Author)

Evaluation of the dose distribution of dynamic conical conformal therapy using a C-arm mounted accelerator

International Nuclear Information System (INIS)

Nakagawa, Keiichi; Aoki, Yukimasa; Ohtomo, Kuni

2001-01-01

Conformal radiation therapy, which is widely utilized in Japan as a standard, highly precise technique has limited advantage in dose confinement because of its coplanar beam entry. An improved form of conformal therapy is delivered by a linac mounted on a C-arm rotatable gantry. The linac head was designed to move along the C-arm with a maximum angle of 60 degrees. Simultaneous rotation of the gantry creates a Dynamic Conical irradiation technique. Dynamic Conical Conformal Therapy (Dyconic Therapy) was developed by combining the technique with continuous MLC motion based on beam's eye views of the target volume. Dose distributions were measured in a phantom using film densitometry and compared with conventional conformal radiation therapy. The measurements showed that the dose distribution conformed to the target shape identified by CT. In addition, the dose distribution for a cancer patient was evaluated through the use of DVHs generated by a treatment planning system. These measurements showed that the dose distribution along the patient's long axis conformed to the shape of the target volume. DVH analysis, however, did not indicate superiority of the present technique over the conventional technique. Angulation of the C-arm gantry allowed the primary beam to strike a larger area of the therapy room. This necessitated adding shielding to the walls and ceiling of the treatment room. It was confirmed that the leakage radiation was reduced to a negligible level by adding an iron plate 20 cm thick to several places on the side walls, by adding an iron plate 9 cm thick to several places on the ceiling, and by increasing the thickness of the concrete ceiling from 70 to 140 cm. The possible usefulness of Dyconic Therapy was confirmed. (author)

Accelerator-based BNCT.

Science.gov (United States)

Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

2014-06-01

The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. © 2013 Elsevier Ltd. All rights reserved.

Low-dose neutron dose response of zebrafish embryos obtained from the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility

International Nuclear Information System (INIS)

Ng, C.Y.P.; Kong, E.Y.; Konishi, T.; Kobayashi, A.; Suya, N.; Cheng, S.H.; Yu, K.N.

2015-01-01

The dose response of embryos of the zebrafish, Danio rerio, irradiated at 5 h post fertilization (hpf) by 2-MeV neutrons with ≤100 mGy was determined. The neutron irradiations were made at the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility in the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A total of 10 neutron doses ranging from 0.6 to 100 mGy were employed (with a gamma-ray contribution of 14% to the total dose), and the biological effects were studied through quantification of apoptosis at 25 hpf. The responses for neutron doses of 10, 20, 25, and 50 mGy approximately fitted on a straight line, while those for neutron doses of 0.6, 1 and 2.5 mGy exhibited neutron hormetic effects. As such, hormetic responses were generically developed by different kinds of ionizing radiations with different linear energy transfer (LET) values. The responses for neutron doses of 70 and 100 mGy were significantly below the lower 95% confidence band of the best-fit line, which strongly suggested the presence of gamma-ray hormesis. - Highlights: • Neutron dose response was determined for embryos of the zebrafish, Danio rerio. • Neutron doses of 0.6, 1 and 2.5 mGy led to neutron hormetic effects. • Neutron doses of 70 and 100 mGy accompanied by gamma rays led to gamma-ray hormesis

Accelerating an Ordered-Subset Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction with a Power Factor and Total Variation Minimization.

Science.gov (United States)

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2016-01-01

In recent years, there has been increased interest in low-dose X-ray cone beam computed tomography (CBCT) in many fields, including dentistry, guided radiotherapy and small animal imaging. Despite reducing the radiation dose, low-dose CBCT has not gained widespread acceptance in routine clinical practice. In addition to performing more evaluation studies, developing a fast and high-quality reconstruction algorithm is required. In this work, we propose an iterative reconstruction method that accelerates ordered-subsets (OS) reconstruction using a power factor. Furthermore, we combine it with the total-variation (TV) minimization method. Both simulation and phantom studies were conducted to evaluate the performance of the proposed method. Results show that the proposed method can accelerate conventional OS methods, greatly increase the convergence speed in early iterations. Moreover, applying the TV minimization to the power acceleration scheme can further improve the image quality while preserving the fast convergence rate.

Evaluation of the environmental equivalent dose rate using area monitors for neutrons in clinical linear accelerators; Avaliacao da taxa de equivalente de dose ambiente utilizando monitores de area para neutrons em aceleradores lineares clinicos

Energy Technology Data Exchange (ETDEWEB)

Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da, E-mail: asalgado@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

2009-07-01

The Neutron Laboratory of the Radioprotection and Dosimetry Institute - IRD/CNEN, Rio de Janeiro, Brazil, initiated studies on the process of calibration of neutron area monitors and the results of the measurements performed at radiotherapy treatment rooms, containing clinical accelerators

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)

Nuclear power plant control room ventilation system design for meeting general criterion 19

International Nuclear Information System (INIS)

Murphy, K.G.; Campe, K.M.

1975-01-01

The requirement for protection of control room personnel against radiation is specified in General Design Criterion 19 of Appendix A, 10 CFR Part 50. The evaluation of a control room design, especially its emergency ventilation system, with respect to radiation protection primarily consists of determining the radiation doses to control room personnel under accident conditions. The accident dose assessment involves modeling and evaluation of radiological source terms, atmospheric transport of airborne activity, and protection features of the control room ventilation system. Some of the assumptions and conservatisms used in the dose analyses are based on the technical review experience of existing or proposed control room designs. A review of over 50 control room designs has revealed a great variety of design concepts, not all of which seem to have been based on radiation protection criteria. A summary of the basic control room protection requirements, design features, dose acceptance criteria, and an outline of the methods used by the Regulatory staff for accident dose evaluation are presented. (U.S.)

Characteristics of induced activity from medical linear accelerators

International Nuclear Information System (INIS)

Wang Yizhen; Evans, Michael D.C.; Podgorsak, Ervin B.

2005-01-01

A study of the induced activity in a medical linear accelerator (linac) room was carried out on several linac installations. Higher beam energy, higher dose rate, and larger field size generally result in higher activation levels at a given point of interest, while the use of multileaf collimators (MLC) can also increase the activation level at the isocenter. Both theoretical and experimental studies reveal that the activation level in the morning before any clinical work increases from Monday to Saturday and then decreases during the weekend. This weekly activation picture keeps stable from one week to another during standard clinical operation of the linac. An effective half-life for a given point in the treatment room can be determined from the measured or calculated activity decay curves. The effective half-life for points inside the treatment field is longer than that for points outside of the field in the patient plane, while a larger field and longer irradiation time can also make the effective half-life longer. The activation level reaches its practical saturation value after a 30 min continuous irradiation, corresponding to 12 000 MU at a 'dose rate' of 400 MU/min. A 'dose' of 300 MU was given 20 times in 15 min intervals to determine the trends in the activation level in a typical clinical mode. As well, a long-term (85 h over a long weekend) decay curve was measured to evaluate the long-term decay of room activation after a typical day of clinical linac use. A mathematical model for the activation level at the isocenter has been established and shown to be useful in explaining and predicting the induced activity levels for typical clinical and experimental conditions. The activation level for a 22 MeV electron beam was also measured and the result shows it is essentially negligible

Shielding evaluation of a medical linear accelerator vault in preparation for installing a high-dose rate 252Cf remote after-loader

International Nuclear Information System (INIS)

Melhus, C. S.; Rivard, M. J.; KurKomelis, J.; Liddle, C. B.; Masse, F. X.

2005-01-01

In support of the effort to begin high-dose rate 252 Cf brachytherapy treatments at Tufts-New England Medical Center, the shielding capabilities of a clinical accelerator vault against the neutron and photon emissions from a 1.124 mg 252 Cf source were examined. Outside the clinical accelerator vault, the fast neutron dose equivalent rate was below the lower limit of detection of a CR-39 etched track detector and below 0.14 ± 0.02 μSv h -1 with a proportional counter, which is consistent, within the uncertainties, with natural background. The photon dose equivalent rate was also measured to be below background levels (0.1 μSv h -1 ) using an ionisation chamber and an optically stimulated luminescence dosemeter. A Monte Carlo simulation of neutron transport through the accelerator vault was performed to validate measured values and determine the thermal-energy to low-energy neutron component. Monte Carlo results showed that the dose equivalent rate from fast neutrons was reduced by a factor of 100,000 after attenuation through the vault wall, and the thermal-energy neutron dose equivalent rate would be an additional factor of 1000 below that of the fast neutrons. Based on these findings, the shielding installed in this facility is sufficient for the use of at least 5.0 mg of 252 Cf. (authors)

Status report of pelletron accelerator and ECR based heavy ion accelerator programme

International Nuclear Information System (INIS)

Gupta, A.K.

2015-01-01

The BARC-TIFR Pelletron Accelerator is completing twenty seven years of round-the-clock operation, serving diverse users from institutions within and outside DAE. Over the years, various developmental activities and application oriented programs have been initiated at Pelletron Accelerator Facility, resulting into enhanced utilization of the accelerator. We have also been pursuing an ECR based heavy ion accelerator programme under XII th Plan, consisting of an 18 GHz superconducting ECR (Electron Cyclotron Resonance) ion source and a room temperature RFQ (Radio Frequency Quadrupole) followed by low and high beta superconducting niobium resonator cavities. This talk will provide the current status of Pelletron Accelerator and the progress made towards the ECR based heavy ion accelerator program at BARC. (author)

Application of a Pelletron accelerator to study total dose radiation effects on 50 GHz SiGe HBTs

Energy Technology Data Exchange (ETDEWEB)

Praveen, K.C.; Pushpa, N.; Naik, P.S. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Cressler, John D. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Tripathi, Ambuj [Inter University Accelerator Centre (IUAC), New Delhi 110 067 (India); Gnana Prakash, A.P., E-mail: gnanaprakash@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Total dose effects of 50 MeV Li3+ ion on 50 GHz SiGe HBTs is investigated. Black-Right-Pointing-Pointer Ion irradiated results were compared with Co-60 gamma results. Black-Right-Pointing-Pointer 50 MeV Li ions create more damage in E-B spacer oxide when compared to Co-60 gamma radiation. Black-Right-Pointing-Pointer Co-60 gamma radiation create more damage in STI oxide when compared to 50 MeV Li ions. Black-Right-Pointing-Pointer Worst case total dose radiation effects can be studied using Pelletron accelerator facilities. - Abstract: We have investigated the effects of 50 MeV lithium ion irradiation on the DC electrical characteristics of first-generation silicon-germanium heterojunction bipolar transistors (50 GHz SiGe HBTs) in the dose range of 600 krad to 100 Mrad. The results of 50 MeV Li{sup 3+} ion irradiation on the SiGe HBTs are compared with 63 MeV proton and Co-60 gamma irradiation results in the same dose range in order to understand the damage induced by different LET species. The radiation response of emitter-base (EB) spacer oxide and shallow trench isolation (STI) oxide to different irradiation types are discussed in this paper. We have also focused on the efficacy in the application of a Pelletron accelerator to study total dose irradiation studies in SiGe HBTs.

Observational infant exploratory [14C]-paracetamol pharmacokinetic microdose/therapeutic dose study with accelerator mass spectrometry bioanalysis

NARCIS (Netherlands)

Garner, C.R.; Park, K.B.; French, N.S.; Earnshaw, C.; Schipani, A.; Selby, A.M.; Byrne, L.; Siner, S.; Crawley, F.P.; Vaes, W.H.J.; Duijn, E. van; ligt, R. de; Varendi, H.; Lass, J.; Grynkiewicz, G.; Maruszak, W.; Turner, M.A.

2015-01-01

Aims The aims of the study were to compare [14C]-paracetamol ([14C]-PARA) paediatric pharmacokinetics (PK) after administration mixed in a therapeutic dose or an isolated microdose and to develop further and validate accelerator mass spectrometry (AMS) bioanalysis in the 0-2 year old age group.

Interplay effect on a 6-MV flattening-filter-free linear accelerator with high dose rate and fast multi-leaf collimator motion treating breast and lung phantoms.

Science.gov (United States)

Netherton, Tucker; Li, Yuting; Nitsch, Paige; Shaitelman, Simona; Balter, Peter; Gao, Song; Klopp, Ann; Muruganandham, Manickam; Court, Laurence

2018-06-01

Using a new linear accelerator with high dose rate (800 MU/min), fast MLC motions (5.0 cm/s), fast gantry rotation (15 s/rotation), and 1 cm wide MLCs, we aimed to quantify the effects of complexity, arc number, and fractionation on interplay for breast and lung treatments under target motion. To study lung interplay, eight VMAT plans (1-6 arcs) and four-nine-field sliding-window IMRT plans varying in complexity were created. For the breast plans, four-four-field sliding-window IMRT plans were created. Using the Halcyon 1.0 linear accelerator, each plan was delivered five times each under sinusoidal breathing motion to a phantom with 20 implanted MOSFET detectors; MOSFET dose (cGy), delivery time, and MU/cGy values were recorded. Maximum and mean dose deviations were calculated from MOSFET data. The number of MOSFETs with at least 19 of 20 detectors agreeing with their expected dose within 5% per fraction was calculated across 10 6 iterations to model dose deviation as function of fraction number for all plan variants. To put interplay plans into clinical context, additional IMRT and VMAT plans were created and delivered for the sites of head and neck, prostate, whole brain, breast, pelvis, and lung. Average modulation and interplay effect were compared to those from conventional linear accelerators, as reported from previous studies. The mean beam modulation for plans created for the Halcyon 1.0 linear accelerator was 2.9 MU/cGy (two- to four-field IMRT breast plans), 6.2 MU/cGy (at least five-field IMRT), and 3.6 MU/cGy (four-arc VMAT). To achieve treatment plan objectives, Halcyon 1.0 VMAT plans require more arcs and modulation than VMAT on conventional linear accelerators. Maximum and mean dose deviations increased with increasing plan complexity under tumor motion for breast and lung treatments. Concerning VMAT plans under motion, maximum, and mean dose deviations were higher for one arc than for two arcs regardless of plan complexity. For plan variants

Evaluation of area monitor response for neutrons in radiation field generated by a 15 MV clinic accelerator; Avaliacao da resposta dos monitores de area para neutrons em campo de radiacao gerado por um acelerador clinico de 15 MV

Energy Technology Data Exchange (ETDEWEB)

Salgado, Ana Paula

2011-07-01

The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)

An accelerated dose escalation with a grass pollen allergoid is safe and well-tolerated: a randomized open label phase II trial.

Science.gov (United States)

Chaker, A M; Al-Kadah, B; Luther, U; Neumann, U; Wagenmann, M

2015-01-01

The number of injections in the dose escalation of subcutaneous immunotherapy (SCIT) is small for some currently used hypoallergenic allergoids, but can still be inconvenient to patients and can impair compliance. The aim of this trial was to compare safety and tolerability of an accelerated to the conventional dose escalation scheme of a grass pollen allergoid. In an open label phase II trial, 122 patients were 1:1 randomized for SCIT using a grass pollen allergoid with an accelerated dose escalation comprising only 4 weekly injections (Group I) or a conventional dose escalation including 7 weekly injections (Group II). Safety determination included the occurrence of local and systemic adverse events. Tolerability was assessed by patients and physicians. Treatment-related adverse events were observed in 22 (36.1 %) patients in Group I and 15 (24.6 %) in Group II. Local reactions were reported by 18 patients in Group I and 11 in Group II. Five Grade 1 systemic reactions (WAO classification) were observed in Group I and 2 in Group II. Grade 2 reactions occurred 3 times in Group I and 2 times in Group II. Tolerability was rated as "good" or "very good" by 53 (86.9 %) patients in Group I and 59 (100 %) in Group II by investigators. Forty-eight patients in Group I (80.0 %) and 54 in Group II (91.5 %) rated tolerability as "good" or "very good". The dose escalation of a grass pollen allergoid can be accelerated with safety and tolerability profiles comparable to the conventional dose escalation.

Stability of a mobile electron linear accelerator system for intraoperative radiation therapy

International Nuclear Information System (INIS)

Beddar, A. Sam

2005-01-01

The flexibility of mobile electron accelerators, which are designed to be transported to an operating room and plugged into a normal 3-phase outlet, make them ideal for use in intraoperative radiation therapy. However, their transportability may cause trepidation among potential users, who may question the stability of such an accelerator over a period of use. In order to address this issue, we have studied the short-term stability of the Mobetron system over 20 daily quality assurance trials. Variations in output generally varied within ±2% for the four energies produced by the unit (4, 6, 9, and 12 MeV) and changes in energy produced an equivalent shift of less than 1 mm on the depth-dose curve. Hours of inactivity, with the Mobetron powered on for use either throughout the day or overnight, led to variations in output of about 1%. Finally, we have tested the long-term stability of the absolute dose output of the Mobetron, which showed a change of about 1% per year

Workshop on Accelerator Operation (WAO 2001)

International Nuclear Information System (INIS)

Bailey, R.

2001-01-01

The 3rd Workshop on Accelerator Operation (WAO 2001) followed earlier workshops in 1996 and 1998. Most topics relevant for the efficient and effective operation of accelerators were covered. These included the tools and utilities necessary in the control rooms; the organization of accelerator operation (process monitoring, shift work, stress); the monitoring of beam quality; safety issues and standards; and questions particularly relevant for superconducting accelerators, in particular cryogenics. (author)

A Combined Shielding Design for a Neutron Generator and a Linear Accelerator at Soreq NRC

International Nuclear Information System (INIS)

Epstein, L.

2014-01-01

A new radiography facility is designed at Soreq NRC. The facility will hold a neutron generator that produces 1.73·109 n/s with an energy of 14 MeV and a linear accelerator that accelerates electrons to an energy of 9 MeV. The two radiation sources will be installed in 2 separate laboratories that will be built in an existing building. Each laboratory will have its own machine and control room. The dose rates around the sources were calculated using the FLUKA Monte Carlo code(1,2). The annual doses were calculated in several regions around the generator and the accelerator laboratories in accordance with the occupancy in each area. The calculated annual doses were compared with the dose limits specified in the Safety at Work Regulations(3) and the IAEC Standard for Protection against Ionizing Radiation. The shielding was designed to comply with the following dose constraints: 0.3 mSv/y for members of the public and 2 mSv/y for radiation workers. Each radiation source is planned to produce radiation for a maximum of 500 hours per year. The dose rate in the direct beam of the accelerator is 30 Gy/min at 1 m from the source and it will be surrounded by a collimator with an opening of 30N-tilde horizontally and 2 mm vertically, 3 m from the radiation source. The leakage radiation dose will not be greater than 1.5 mGy/min (0.005% of the direct beam, according to the manufacturer). The leakage radiation will be produced isotropically. The neutron generator will be surrounded by a shielding made of a 10 cm iron cylinder (density 7.87 g/cm3), surrounded by 50 cm of borated polyethylene (atomic percent: H (13.8%), C (82.2%), B (4%), density: 0.92 g/cm3) and 5 cm of lead (density 11.35 g/cm3). The neutron generator shielding was not designed or required in the present shielding design but was considered in the shielding calculations

The radiation field measurement and analysis outside the shielding of A 10 MeV electron irradiation accelerator

Science.gov (United States)

Shang, Jing; Li, Juexin; Xu, Bing; Li, Yuxiong

2011-10-01

Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the 60Co isotope approach. However, the electron accelerator exposes potential radiation hazards. To protect workers and the public from exposure to radiation, the radiation field around the electronic accelerator must be assessed, especially that outside the shielding. Thus, we measured the radiation dose at different positions outside the shielding of a 10-MeV electron accelerator using a new data-acquisition unit named Mini-DDL (Mini-Digital Data Logging). The measurements accurately reflect the accelerator's radiation status. In this paper, we present our findings, results and compare them with our theoretical calculations. We conclude that the measurements taken outside the irradiation hall are consistent with the findings from our calculations, except in the maze outside the door of the accelerator room. We discuss the reason for this discrepancy.

The radiation field measurement and analysis outside the shielding of A 10 MeV electron irradiation accelerator

Energy Technology Data Exchange (ETDEWEB)

Shang Jing [National Synchrotron Radiation Lab, University of Science and Technology of China (China); Li Juexin, E-mail: juexin@ustc.edu.cn [National Synchrotron Radiation Lab, University of Science and Technology of China (China); Xu Bing; Li Yuxiong [National Synchrotron Radiation Lab, University of Science and Technology of China (China)

2011-10-01

Electron accelerators are employed widely for diverse purposes in the irradiation-processing industry, from sterilizing medical products to treating gemstones. Because accelerators offer high efficiency, high power, and require little preventative maintenance, they are becoming more and more popular than using the {sup 60}Co isotope approach. However, the electron accelerator exposes potential radiation hazards. To protect workers and the public from exposure to radiation, the radiation field around the electronic accelerator must be assessed, especially that outside the shielding. Thus, we measured the radiation dose at different positions outside the shielding of a 10-MeV electron accelerator using a new data-acquisition unit named Mini-DDL (Mini-Digital Data Logging). The measurements accurately reflect the accelerator's radiation status. In this paper, we present our findings, results and compare them with our theoretical calculations. We conclude that the measurements taken outside the irradiation hall are consistent with the findings from our calculations, except in the maze outside the door of the accelerator room. We discuss the reason for this discrepancy.

Accelerator mass spectrometry and associated facilities at Inter-University Accelerator Centre, New Delhi, India

International Nuclear Information System (INIS)

Kumar, Pankaj; Bohra, Archna; Ojha, S.; Gargari, S.; Joshi, R.; Roonwal, G.S.; Chopra, S.; Pattanaik, J.K.; Balakrishnan, S.

2011-01-01

Accelerator Mass Spectrometry (AMS) facility at Inter-University Accelerator Centre (IUAC) is developed by upgrading its existing 15UD Pelletron accelerator. Since last two decades Pelletron is mainly used for nuclear physics, materials science, atomic physics, radiation biology and accelerator mass spectrometry is recent development. In addition, a chemistry laboratory in clean room for the chemical processing of samples for AMS studies has also been established. At present the AMS facility is used for 10 Be, 26 Al measurements and soon other long lived radio-isotopes will also be used

Determination of the dose equivalents due to neutrons produced during therapeutic irradiations with a Varian CLINAC 2500

International Nuclear Information System (INIS)

Carrillo, Ricardo E.

1991-01-01

This experiment it was designed to quantify that so important it is the dose equivalent deposited by the neutron flow that is generated by photonuclear reactions during therapeutic irradiations with X rays of produced high-energy for an accelerator Varian CLINAC 2500. This accelerator type is routinely used in the Department of Radiotherapy of the Hospital of the University of Wisconsin, E.U. The equivalent dose was measured in diverse towns of the room of irradiations using the activation of thin sheets of gold put in the center of plastic recipients full with water. In general, the recipients were 1 m or more than the floor and at distances still bigger than the walls. The irradiations were made using photons with the highest energy that you can select with this team - 24 MeV. The due equivalent dose to neutrons taken place here by the energy photons used they were measured and reported. (author)

Occupational radiation protection around medical linear accelerators: measurements and semi-analytical approaches

International Nuclear Information System (INIS)

Donadille, L.; Derreumaux, S.; Mantione, J.; Robbes, I.; Trompier, F.; Amgarou, K.; Asselineau, B.; Martin, A.

2008-01-01

Full text: X-rays produced by high-energy (larger than 6 MeV) medical electron linear accelerators create secondary neutron radiation fields mainly by photonuclear reactions inside the materials of the accelerator head, the patient and the walls of the therapy room. Numerous papers were devoted to the study of neutron production in medical linear accelerators and resulting decay of activation products. However, data associated to doses delivered to workers in treatment conditions are scarce. In France, there are more than 350 external radiotherapy facilities representing almost all types of techniques and designs. IRSN carried out a measurement campaign in order to investigate the variation of the occupational dose according the different encountered situations. Six installations were investigated, associated with the main manufacturers (Varian, Elekta, General Electrics, Siemens), for several nominal energies, conventional and IMRT techniques, and bunker designs. Measurements were carried out separately for neutron and photon radiation fields, and for radiation associated with the decay of the activation products, by means of radiometers, tissue-equivalent proportional counters and spectrometers (neutron and photon spectrometry). They were performed at the positions occupied by the workers, i.e. outside the bunker during treatments, inside between treatments. Measurements have been compared to published data. In addition, semi-empirical analytical approaches recommended by international protocols were used to estimate doses inside and outside the bunkers. The results obtained by both approaches were compared and analysed. The annual occupational effective dose was estimated to about 1 mSv, including more than 50 % associated with the decay of activation products and less than 10 % due to direct exposure to leakage neutrons produced during treatments. (author)

[Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

Science.gov (United States)

Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

2015-12-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

Evaluation of radiation dose during sent-graft treatment using a hybrid operating room system

International Nuclear Information System (INIS)

Haga, Yoshihiro; Kaga, Yuji; Chida, Koichi

2015-01-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR). When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system. (author)

A photon source model based on particle transport in a parameterized accelerator structure for Monte Carlo dose calculations.

Science.gov (United States)

Ishizawa, Yoshiki; Dobashi, Suguru; Kadoya, Noriyuki; Ito, Kengo; Chiba, Takahito; Takayama, Yoshiki; Sato, Kiyokazu; Takeda, Ken

2018-05-17

An accurate source model of a medical linear accelerator is essential for Monte Carlo (MC) dose calculations. This study aims to propose an analytical photon source model based on particle transport in parameterized accelerator structures, focusing on a more realistic determination of linac photon spectra compared to existing approaches. We designed the primary and secondary photon sources based on the photons attenuated and scattered by a parameterized flattening filter. The primary photons were derived by attenuating bremsstrahlung photons based on the path length in the filter. Conversely, the secondary photons were derived from the decrement of the primary photons in the attenuation process. This design facilitates these sources to share the free parameters of the filter shape and be related to each other through the photon interaction in the filter. We introduced two other parameters of the primary photon source to describe the particle fluence in penumbral regions. All the parameters are optimized based on calculated dose curves in water using the pencil-beam-based algorithm. To verify the modeling accuracy, we compared the proposed model with the phase space data (PSD) of the Varian TrueBeam 6 and 15 MV accelerators in terms of the beam characteristics and the dose distributions. The EGS5 Monte Carlo code was used to calculate the dose distributions associated with the optimized model and reference PSD in a homogeneous water phantom and a heterogeneous lung phantom. We calculated the percentage of points passing 1D and 2D gamma analysis with 1%/1 mm criteria for the dose curves and lateral dose distributions, respectively. The optimized model accurately reproduced the spectral curves of the reference PSD both on- and off-axis. The depth dose and lateral dose profiles of the optimized model also showed good agreement with those of the reference PSD. The passing rates of the 1D gamma analysis with 1%/1 mm criteria between the model and PSD were 100% for 4�

Calorimetry at industrial electron accelerators

DEFF Research Database (Denmark)

Miller, Arne; Kovacs, A.

1985-01-01

Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as grap......Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials...

MO-F-CAMPUS-I-03: GPU Accelerated Monte Carlo Technique for Fast Concurrent Image and Dose Simulation

Energy Technology Data Exchange (ETDEWEB)

Becchetti, M; Tian, X; Segars, P; Samei, E [Clinical Imaging Physics Group, Department of Radiology, Duke University Me, Durham, NC (United States)

2015-06-15

Purpose: To develop an accurate and fast Monte Carlo (MC) method of simulating CT that is capable of correlating dose with image quality using voxelized phantoms. Methods: A realistic voxelized phantom based on patient CT data, XCAT, was used with a GPU accelerated MC code for helical MDCT. Simulations were done with both uniform density organs and with textured organs. The organ doses were validated using previous experimentally validated simulations of the same phantom under the same conditions. Images acquired by tracking photons through the phantom with MC require lengthy computation times due to the large number of photon histories necessary for accurate representation of noise. A substantial speed up of the process was attained by using a low number of photon histories with kernel denoising of the projections from the scattered photons. These FBP reconstructed images were validated against those that were acquired in simulations using many photon histories by ensuring a minimal normalized root mean square error. Results: Organ doses simulated in the XCAT phantom are within 10% of the reference values. Corresponding images attained using projection kernel smoothing were attained with 3 orders of magnitude less computation time compared to a reference simulation using many photon histories. Conclusion: Combining GPU acceleration with kernel denoising of scattered photon projections in MC simulations allows organ dose and corresponding image quality to be attained with reasonable accuracy and substantially reduced computation time than is possible with standard simulation approaches.

MO-F-CAMPUS-I-03: GPU Accelerated Monte Carlo Technique for Fast Concurrent Image and Dose Simulation

International Nuclear Information System (INIS)

Becchetti, M; Tian, X; Segars, P; Samei, E

2015-01-01

Purpose: To develop an accurate and fast Monte Carlo (MC) method of simulating CT that is capable of correlating dose with image quality using voxelized phantoms. Methods: A realistic voxelized phantom based on patient CT data, XCAT, was used with a GPU accelerated MC code for helical MDCT. Simulations were done with both uniform density organs and with textured organs. The organ doses were validated using previous experimentally validated simulations of the same phantom under the same conditions. Images acquired by tracking photons through the phantom with MC require lengthy computation times due to the large number of photon histories necessary for accurate representation of noise. A substantial speed up of the process was attained by using a low number of photon histories with kernel denoising of the projections from the scattered photons. These FBP reconstructed images were validated against those that were acquired in simulations using many photon histories by ensuring a minimal normalized root mean square error. Results: Organ doses simulated in the XCAT phantom are within 10% of the reference values. Corresponding images attained using projection kernel smoothing were attained with 3 orders of magnitude less computation time compared to a reference simulation using many photon histories. Conclusion: Combining GPU acceleration with kernel denoising of scattered photon projections in MC simulations allows organ dose and corresponding image quality to be attained with reasonable accuracy and substantially reduced computation time than is possible with standard simulation approaches

TH-AB-BRA-07: PENELOPE-Based GPU-Accelerated Dose Calculation System Applied to MRI-Guided Radiation Therapy

International Nuclear Information System (INIS)

Wang, Y; Mazur, T; Green, O; Hu, Y; Li, H; Rodriguez, V; Wooten, H; Yang, D; Zhao, T; Mutic, S; Li, H

2016-01-01

Purpose: The clinical commissioning of IMRT subject to a magnetic field is challenging. The purpose of this work is to develop a GPU-accelerated Monte Carlo dose calculation platform based on PENELOPE and then use the platform to validate a vendor-provided MRIdian head model toward quality assurance of clinical IMRT treatment plans subject to a 0.35 T magnetic field. Methods: We first translated PENELOPE from FORTRAN to C++ and validated that the translation produced equivalent results. Then we adapted the C++ code to CUDA in a workflow optimized for GPU architecture. We expanded upon the original code to include voxelized transport boosted by Woodcock tracking, faster electron/positron propagation in a magnetic field, and several features that make gPENELOPE highly user-friendly. Moreover, we incorporated the vendor-provided MRIdian head model into the code. We performed a set of experimental measurements on MRIdian to examine the accuracy of both the head model and gPENELOPE, and then applied gPENELOPE toward independent validation of patient doses calculated by MRIdian’s KMC. Results: We achieve an average acceleration factor of 152 compared to the original single-thread FORTRAN implementation with the original accuracy preserved. For 16 treatment plans including stomach (4), lung (2), liver (3), adrenal gland (2), pancreas (2), spleen (1), mediastinum (1) and breast (1), the MRIdian dose calculation engine agrees with gPENELOPE with a mean gamma passing rate of 99.1% ± 0.6% (2%/2 mm). Conclusions: We developed a Monte Carlo simulation platform based on a GPU-accelerated version of PENELOPE. We validated that both the vendor provided head model and fast Monte Carlo engine used by the MRIdian system are accurate in modeling radiation transport in a patient using 2%/2 mm gamma criteria. Future applications of this platform will include dose validation and accumulation, IMRT optimization, and dosimetry system modeling for next generation MR-IGRT systems.

TH-AB-BRA-07: PENELOPE-Based GPU-Accelerated Dose Calculation System Applied to MRI-Guided Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Wang, Y; Mazur, T; Green, O; Hu, Y; Li, H; Rodriguez, V; Wooten, H; Yang, D; Zhao, T; Mutic, S; Li, H [Washington University School of Medicine, Saint Louis, MO (United States)

2016-06-15

Purpose: The clinical commissioning of IMRT subject to a magnetic field is challenging. The purpose of this work is to develop a GPU-accelerated Monte Carlo dose calculation platform based on PENELOPE and then use the platform to validate a vendor-provided MRIdian head model toward quality assurance of clinical IMRT treatment plans subject to a 0.35 T magnetic field. Methods: We first translated PENELOPE from FORTRAN to C++ and validated that the translation produced equivalent results. Then we adapted the C++ code to CUDA in a workflow optimized for GPU architecture. We expanded upon the original code to include voxelized transport boosted by Woodcock tracking, faster electron/positron propagation in a magnetic field, and several features that make gPENELOPE highly user-friendly. Moreover, we incorporated the vendor-provided MRIdian head model into the code. We performed a set of experimental measurements on MRIdian to examine the accuracy of both the head model and gPENELOPE, and then applied gPENELOPE toward independent validation of patient doses calculated by MRIdian’s KMC. Results: We achieve an average acceleration factor of 152 compared to the original single-thread FORTRAN implementation with the original accuracy preserved. For 16 treatment plans including stomach (4), lung (2), liver (3), adrenal gland (2), pancreas (2), spleen (1), mediastinum (1) and breast (1), the MRIdian dose calculation engine agrees with gPENELOPE with a mean gamma passing rate of 99.1% ± 0.6% (2%/2 mm). Conclusions: We developed a Monte Carlo simulation platform based on a GPU-accelerated version of PENELOPE. We validated that both the vendor provided head model and fast Monte Carlo engine used by the MRIdian system are accurate in modeling radiation transport in a patient using 2%/2 mm gamma criteria. Future applications of this platform will include dose validation and accumulation, IMRT optimization, and dosimetry system modeling for next generation MR-IGRT systems.

Neutron doses to personnel from a 24 MeV betatron

International Nuclear Information System (INIS)

Beckham, W.A; Entwistle, R.F.

1987-01-01

Neutrons are produced by bombardment of most materials by high-energy photons. Because the x-ray shielding around high-energy x-ray generators may not have been designed with neutrons in mind there may be unexpected contributions to the radiation doses of staff working in the immediate vicinity. Neutron fluxes in the working area close to an Allis-Chalmers 24 MeV betatron have been measured using a lithium-6-loaded scintillator and the dose rates calculated. Hazard of staff has been found to be low; typical dose-equivalent rates in occupied areas range from 0.0042 to 0.012 mrem/hour. The flux of fast neutrons in the treatment room was found to be essentially zero. Measurements of neutron flux may be routinely performed using the scintillation detector (NE 912) described, and could usefully form part of the acceptance protocol for any new accelerator

Evaluation of shielding capability of controlled area for CT examination room

International Nuclear Information System (INIS)

Suzuki, Shoichi; Asada, Yasuki; Nakai, Takayo; Takeuchi, Kichito; Kinoshita, Kazuo; Watanabe, Nobuyuki; Koga, Sukehiko

2002-01-01

With the revision of the law in April, 2001, the effective dose at the boundary of the controlled area was set at 1.3 mSv/3M. Whether the shielding capability of the CT room satisfied the provisions of the law or not was confirmed by actual measurements. Both thermo luminescence dosemeter (TLD) and electronic dosemeter were used to measure the radiation doses. The shielding capability of the gantry was studied both inside and outside the room for a week as a basic experiment. On the basis of the data thus obtained doses accumulated in 3 months were estimated. According to the results of 3 month-measurement, the doses outside the wall of the CT room were about 200μ Sv. This numerical value was comparable to the background level of the evaluation point. The results above assured that the shielding capability of the CT room satisfied the provisions of the law well. (author)

Control room habitability system review models

International Nuclear Information System (INIS)

Gilpin, H.

1990-12-01

This report provides a method of calculating control room operator doses from postulated reactor accidents and chemical spills as part of the resolution of TMI Action Plan III.D.3.4. The computer codes contained in this report use source concentrations calculated by either TACT5, FPFP, or EXTRAN, and transport them via user-defined flow rates to the control room envelope. The codes compute doses to six organs from up to 150 radionuclides (or 1 toxic chemical) for time steps as short as one second. Supporting codes written in Clipper assist in data entry and manipulation, and graphically display the results of the FORTRAN calculations. 7 refs., 22 figs

The MARS15-based FermiCORD code system for calculation of the accelerator-induced residual dose

Energy Technology Data Exchange (ETDEWEB)

Grebe, A.; Leveling, A.; Lu, T.; Mokhov, N.; Pronskikh, V.

2018-01-01

The FermiCORD code system, a set of codes based on MARS15 that calculates the accelerator-induced residual doses at experimental facilities of arbitrary configurations, has been developed. FermiCORD is written in C++ as an add-on to Fortran-based MARS15. The FermiCORD algorithm consists of two stages: 1) simulation of residual doses on contact with the surfaces surrounding the studied location and of radionuclide inventories in the structures surrounding those locations using MARS15, and 2) simulation of the emission of the nuclear decay gamma-quanta by the residuals in the activated structures and scoring the prompt doses of these gamma-quanta at arbitrary distances from those structures. The FermiCORD code system has been benchmarked against similar algorithms based on other code systems and showed a good agreement. The code system has been applied for calculation of the residual dose of the target station for the Mu2e experiment and the results have been compared to approximate dosimetric approaches.

2 MeV, 60 kW dual-beam type electron accelerator irradiation facility

International Nuclear Information System (INIS)

Yotsumoto, Keiichi; Kanazawa, Takao; Haruyama, Yasuyuki; Agematsu, Takashi; Mizuhashi, Kiyoshi; Sunaga, Hiromi; Washino, Masamitsu; Tamura, Naoyuki

1984-02-01

The specification of new irradiation facility which has been constructed from 1978 through 1981 as the replacement of 1st Accelerator of JAERI, TRCRE are described. The accelerator is the Cockcroft-Walton type and both vertical and horizontal accelerating tubes are arranged on a single high voltage generator. Transferring of the high voltage to the horizontal accelerating tube is performed with the high voltage changing system in the pressure vessel. The output ratings of the accelerator are 2 MV of acceleration voltage and 30 mA of beam current. By providing the dual beam system, two irradiation rooms, one for vertical and the other for horizontal beam, are independently operationable. Persons can enter the horizontal irradiation room for experimental setting even when the vertical irradiation room is in operation. The specification of the buildings, the exhaust air treatment system, the irradiation conveyor and the safety observation system are also described. (author)

The peripheral dose outside the applicator in electron beams of Oncor linear accelerator

International Nuclear Information System (INIS)

Iktueren, B.; Bilge, H.; Karacam, S.; Atkovar, G.

2012-01-01

In this study, the peripheral dose outside the applicator was measured using electron beams produced by an Oncor linear accelerator and compared with the data of the treatment planning system (TPS). The dose profiles have been measured, by using a water-equivalent slab phantom and a parallel plate ionisation chamber, at 6, 9 and 15 MeV energy levels in 5 x 5, 10 x 10, 15 x 15, 20 x 20 and 25 x 25 cm 2 applicators and at 0, 10 and 20 deg. gantry angles; and at the surface, 0.2, 0.5, 1 cm and d max depth for each electron energy level. The peripheral dose has been determined with these profiles by normalisation at the field central beam axis (CAX). It has been noticed that, using a 10 x 10 cm 2 applicator, there is a 1.4 % dose peak on the surface 6 cm away from the field edge where the field CAX is at 100 %, at a gantry angle of 0 deg. with 6 and 9 MeV electron beams; also for the 15 MeV electron beam there is a 2.3 % dose peak. It has been discovered that the peak dose approaches a minimum depending on the increase in depth and reaches 2.5-4 % depending on the growth of the field dimension. At gantry angles of 10 and 20 deg., 6 and 9 MeV electron beams created small peaks and a maximum dose could be reached at 0.2 and 1 cm depth. Electron beam of 15 MeV did not peak at depths of 0.2 and 1 cm at gantry angles of 10 and 20 deg.. The measured peripheral dose outside the applicators has been compared with the data from a TPS's computer using the Pencil Beam algorithm; it has been stated that dose calculations can be made as far as 3 cm outside the field. In conclusion, the TPS is not sufficient to measure the peripheral dose outside the applicators, and this dose can only be determined by direct measurement. (authors)

The peripheral dose outside the applicator in electron beams of Oncor linear accelerator.

Science.gov (United States)

Iktueren, Basak; Bilge, Hatice; Karacam, Songul; Atkovar, Gulyuz

2012-06-01

In this study, the peripheral dose outside the applicator was measured using electron beams produced by an Oncor linear accelerator and compared with the data of the treatment planning system (TPS). The dose profiles have been measured, by using a water-equivalent slab phantom and a parallel plate ionisation chamber, at 6, 9 and 15 MeV energy levels in 5×5, 10×10, 15×15, 20×20 and 25×25 cm(2) applicators and at 0, 10 and 20° gantry angles; and at the surface, 0.2, 0.5, 1 cm and d(max) depth for each electron energy level. The peripheral dose has been determined with these profiles by normalisation at the field central beam axis (CAX). It has been noticed that, using a 10×10 cm(2) applicator, there is a 1.4 % dose peak on the surface 6 cm away from the field edge where the field CAX is at 100 %, at a gantry angle of 0° with 6 and 9 MeV electron beams; also for the 15 MeV electron beam there is a 2.3 % dose peak. It has been discovered that the peak dose approaches a minimum depending on the increase in depth and reaches 2.5-4 % depending on the growth of the field dimension. At gantry angles of 10 and 20°, 6 and 9 MeV electron beams created small peaks and a maximum dose could be reached at 0.2 and 1 cm depth. Electron beam of 15 MeV did not peak at depths of 0.2 and 1 cm at gantry angles of 10 and 20°. The measured peripheral dose outside the applicators has been compared with the data from a TPS's computer using the Pencil Beam algorithm; it has been stated that dose calculations can be made as far as 3 cm outside the field. In conclusion, the TPS is not sufficient to measure the peripheral dose outside the applicators, and this dose can only be determined by direct measurement.

Evolution of dose calculation models for proton-therapy treatment planning

International Nuclear Information System (INIS)

Vidal, Marie

2011-01-01

This work was achieved in collaboration between the Institut Curie proton-therapy Center of Orsay (ICPO), the DOSIsoft company and the CREATIS laboratory, in order to develop a new dose calculation model for the new ICPO treatment room. A new accelerator and gantry room from the IBA company were installed during the up-grade project of the proton-therapy center, with the intention of enlarging the cancer localizations treated at ICPO. Developing a package of methods and new dose calculation algorithms to adapt them to the new specific characteristics of the delivered beams by the IBA system is the first goal of this PhD work. They all aim to be implemented in the DOSIsoft treatment planning software, Isogray. First, the double scattering technique is treated in taking into account major differences between the IBA system and the ICPO fixed beam lines passive system. Secondly, a model is explored for the scanned beams modality. The second objective of this work is improving the Ray-Tracing and Pencil-Beam dose calculation models already in use. For the double scattering and uniform scanning techniques, the patient personalized collimator at the end of the beam line causes indeed a patient dose distribution contamination. A reduction method of that phenomenon was set up for the passive beam system. An analytical model was developed which describes the contamination function with parameters validated through Monte-Carlo simulations on the GATE platform. It allows us to apply those methods to active scanned beams [fr

Obtaining the intrinsic electron spectrum of linear accelerators using the relation between the current of the bending magnet and the absorbed dose in water

International Nuclear Information System (INIS)

Vega, Jose M. de la; Guirado, Damian; Vilches, Manuel; Perdices, Jose I.; Lallena, Antonio M.

2008-01-01

Purpose. To present a novel methodology to model the intrinsic electron spectra of a linear accelerator and its situation with respect to the energy window. Methods. The spectra are obtained by fitting the variation of R 50 and the maximum dose rate measured in a water phantom with the bending magnet current. The obtained spectra are verified with a realistic Monte Carlo simulation of the accelerator. Results. The intrinsic spectra and their relative position with respect to the energy window of the bending magnet have been obtained for a Siemens Mevatron KDS and an ELEKTA SL20 accelerators. Conclusions. Using this method in the commissioning and scheduled revisions of the accelerator, the tuning of the current of the bending magnet could be done in such a way that both the quality of the beam and the dose rate would reach a better long-term stability

Shield design of concrete wall between decay tank room and primary pump room in TRIGA facility

International Nuclear Information System (INIS)

Khan, M. J. H.; Rahman, M.; Haque, A.; Zulquarnain, A.; Ahmed, F. U.; Bhuiyan, S. I.

2007-01-01

The objective of this study is to recommend the radiation protection design parameters from the shielding point of view for concrete wall between the decay tank room and the primary pump room in TRIGA Mark-II research reactor facility. The shield design for this concrete wall has been performed with the help of Point-kernel Shielding Code Micro-Shield 5.05 and this design was also validated based on the measured dose rate values with Radiation Survey Meter (G-M Counter) considering the ICRP-60 (1990) recommendations for occupational dose rate limit (10 μSv/hr). The recommended shield design parameters are: (i) thickness of 114.3 cm Ilmenite-Magnetite Concrete (IMC) or 129.54 cm Ordinary Reinforced Concrete (ORC) for concrete wall A (ii) thickness of 66.04 cm Ilmenite-Magnetite Concrete (IMC) or 78.74 cm Ordinary Reinforced Concrete (ORC) for concrete wall B and (iii) door thickness of 3.175 cm Mild Steel (MS) on the entrance of decay tank room. In shielding efficiency analysis, the use of I-M concrete in the design of this concrete wall shows that it reduced the dose rate by a factor of at least 3.52 times approximately compared to ordinary reinforced concrete

Towards MRI-guided linear accelerator control: gating on an MRI accelerator.

Science.gov (United States)

Crijns, S P M; Kok, J G M; Lagendijk, J J W; Raaymakers, B W

2011-08-07

To boost the possibilities of image guidance in radiotherapy by providing images with superior soft-tissue contrast during treatment, we pursue diagnostic quality MRI functionality integrated with a linear accelerator. Large respiration-induced semi-periodic target excursions hamper treatment of cancer of the abdominal organs. Methods to compensate in real time for such motion are gating and tracking. These strategies are most effective in cases where anatomic motion can be visualized directly, which supports the use of an integrated MRI accelerator. We establish here an infrastructure needed to realize gated radiation delivery based on MR feedback and demonstrate its potential as a first step towards more advanced image guidance techniques. The position of a phantom subjected to one-dimensional periodic translation is tracked with the MR scanner. Real-time communication with the MR scanner and control of the radiation beam are established. Based on the time-resolved position of the phantom, gated radiation delivery to the phantom is realized. Dose distributions for dynamic delivery conditions with varying gating windows are recorded on gafchromic film. The similarity between dynamically and statically obtained dose profiles gradually increases as the gating window is decreased. With gating windows of 5 mm, we obtain sharp dose profiles. We validate our gating implementation by comparing measured dose profiles to theoretical profiles calculated using the knowledge of the imposed motion pattern. Excellent correspondence is observed. At the same time, we show that real-time on-line reconstruction of the accumulated dose can be performed using time-resolved target position information. This facilitates plan adaptation not only on a fraction-to-fraction scale but also during one fraction, which is especially valuable in highly accelerated treatment strategies. With the currently established framework and upcoming improvements to our prototype-integrated MRI accelerator

The effects of ionizing radiation on eight cardiac pacemakers and the influence of electromagnetic interference from two linear accelerators

International Nuclear Information System (INIS)

Venselaar, J.L.M.

1985-01-01

Eight cardiac pacemakers were irradiated in a cobalt-60 beam. Two out of six demand-type pacemakers showed an alarming decrease in pulse repetition frequency when irradiated to dose levels that are used in radiotherapy. Two modern programmable pacemakers showed a failure at a dose of 97 and 147 Gy, respectively. The dose levels at which these failures occurred were low enough to recommend that cardiac pacemakers should always be kept outside the radiation beam. The signals induced by electromagnetic interference (EMI) from two linear accelerators were measured using a simulation model of a pacemaker. In the laboratory, 22 modern-type pacemakers were tested with these signals to determine the sensitivity for the electromagnetic fields in the treatment rooms. It was observed that an inhibition of one pacemaker pulse was to be expected on one of the two linear accelerators when switching the machine on and off. No permanent effects were found. These findings resulted in the recommendation in our department not to use this treatment machine for radiation therapy of pacemaker-bearing patients. (orig.)

SU-E-T-226: Junction Free Craniospinal Irradiation in Linear Accelerator Using Volumetric Modulated Arc Therapy : A Novel Technique Using Dose Tapering

International Nuclear Information System (INIS)

Sarkar, B; Roy, S; Paul, S; Munshi, A; Roy, Shilpi; Jassal, K; Ganesh, T; Mohanti, BK

2014-01-01

Purpose: Spatially separated fields are required for craniospinal irradiation due to field size limitation in linear accelerator. Field junction shits are conventionally done to avoid hot or cold spots. Our study was aimed to demonstrate the feasibility of junction free irradiation plan of craniospinal irradiation (CSI) for Meduloblastoma cases treated in linear accelerator using Volumetric modulated arc therapy (VMAT) technique. Methods: VMAT was planned using multiple isocenters in Monaco V 3.3.0 and delivered in Elekta Synergy linear accelerator. A full arc brain and 40° posterior arc spine fields were planned using two isocentre for short (<1.3 meter height ) and 3 isocentres for taller patients. Unrestricted jaw movement was used in superior-inferior direction. Prescribed dose to PTV was achieved by partial contribution from adjacent beams. A very low dose gradient was generated to taper the isodoses over a long length (>10 cm) at the conventional field junction. Results: In this primary study five patients were planned and three patients were delivered using this novel technique. As the dose contribution from the adjacent beams were varied (gradient) to create a complete dose distribution, therefore there is no specific junction exists in the plan. The junction were extended from 10–14 cm depending on treatment plan. Dose gradient were 9.6±2.3% per cm for brain and 7.9±1.7 % per cm for spine field respectively. Dose delivery error due to positional inaccuracy was calculated for brain and spine field for ±1mm, ±2mm, ±3mm and ±5 mm were 1%–0.8%, 2%–1.6%, 2.8%–2.4% and 4.3%–4% respectively. Conclusion: Dose tapering in junction free CSI do not require a junction shift. Therefore daily imaging for all the field is also not essential. Due to inverse planning dose to organ at risk like thyroid kidney, heart and testis can be reduced significantly. VMAT gives a quicker delivery than Step and shoot or dynamic IMRT

SU-E-T-226: Junction Free Craniospinal Irradiation in Linear Accelerator Using Volumetric Modulated Arc Therapy : A Novel Technique Using Dose Tapering

Energy Technology Data Exchange (ETDEWEB)

Sarkar, B; Roy, S; Paul, S; Munshi, A; Roy, Shilpi; Jassal, K; Ganesh, T; Mohanti, BK [Fortis Memorial Research Institute, Gurgaon (India)

2014-06-01

Purpose: Spatially separated fields are required for craniospinal irradiation due to field size limitation in linear accelerator. Field junction shits are conventionally done to avoid hot or cold spots. Our study was aimed to demonstrate the feasibility of junction free irradiation plan of craniospinal irradiation (CSI) for Meduloblastoma cases treated in linear accelerator using Volumetric modulated arc therapy (VMAT) technique. Methods: VMAT was planned using multiple isocenters in Monaco V 3.3.0 and delivered in Elekta Synergy linear accelerator. A full arc brain and 40° posterior arc spine fields were planned using two isocentre for short (<1.3 meter height ) and 3 isocentres for taller patients. Unrestricted jaw movement was used in superior-inferior direction. Prescribed dose to PTV was achieved by partial contribution from adjacent beams. A very low dose gradient was generated to taper the isodoses over a long length (>10 cm) at the conventional field junction. Results: In this primary study five patients were planned and three patients were delivered using this novel technique. As the dose contribution from the adjacent beams were varied (gradient) to create a complete dose distribution, therefore there is no specific junction exists in the plan. The junction were extended from 10–14 cm depending on treatment plan. Dose gradient were 9.6±2.3% per cm for brain and 7.9±1.7 % per cm for spine field respectively. Dose delivery error due to positional inaccuracy was calculated for brain and spine field for ±1mm, ±2mm, ±3mm and ±5 mm were 1%–0.8%, 2%–1.6%, 2.8%–2.4% and 4.3%–4% respectively. Conclusion: Dose tapering in junction free CSI do not require a junction shift. Therefore daily imaging for all the field is also not essential. Due to inverse planning dose to organ at risk like thyroid kidney, heart and testis can be reduced significantly. VMAT gives a quicker delivery than Step and shoot or dynamic IMRT.

Gaining control room habitability margin at the Palisades Plant

International Nuclear Information System (INIS)

Harden, P.A.

1993-01-01

The bounding design-basis accident for control room habitability is the loss-of-coolant accident (LOCA). At Palisades, very little margin existed between the calculated control room operator thyroid dose and the 0.3-Sv (30-rem) limit of Standard Review Plan (SRP) 6.4. Also, a low rate of unfiltered air leakage into the control room during the emergency mode of operation, 5.5 x 10 -3 m 3 /s (11.6 ft 3 /min), was accounted for in the control room habitability analysis. The control room heating, ventilating and air-conditioning system at Palisades has louvered isolation dampers for the normal air intake that are exposed to a negative pressure. Considering the small margin to the thyroid dose limits and the leakage characteristics of louvered dampers, a low allowable rate of unfiltered air in-leakage raised some concern. A significant effort has been initiated to alleviate control room habitability concerns at Palisades. The first step in this effort was to evaluate the calculational models for control room habitability and gain margin through updated analytical methods. To accomplish this, a new radiological consequence analysis for the LOCA was completed

Accelerated Threshold Fatigue Crack Growth Effect-Powder Metallurgy Aluminum Alloy

Science.gov (United States)

Piascik, R. S.; Newman, J. A.

2002-01-01

Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low (Delta) K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = K(sub min)/K(sub max)). The near threshold accelerated FCG rates are exacerbated by increased levels of K(sub max) (K(sub max) = 0.4 K(sub IC)). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and K(sub max) influenced accelerated crack growth is time and temperature dependent.

Standard Test Method for Measuring Dose for Use in Linear Accelerator Pulsed Radiation Effects Tests

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 This test method covers a calorimetric measurement of the total dose delivered in a single pulse of electrons from an electron linear accelerator or a flash X-ray machine (FXR, e-beam mode) used as an ionizing source in radiation-effects testing. The test method is designed for use with pulses of electrons in the energy range from 10 to 50 MeV and is only valid for cases in which both the calorimeter and the test specimen to be irradiated are“thin” compared to the range of these electrons in the materials of which they are constructed. 1.2 The procedure described can be used in those cases in which (1) the dose delivered in a single pulse is 5 Gy (matl) (500 rd (matl)) or greater, or (2) multiple pulses of a lower dose can be delivered in a short time compared to the thermal time constant of the calorimeter. Matl refers to the material of the calorimeter. The minimum dose per pulse that can be acceptably monitored depends on the variables of the particular test, including pulse rate, pulse uniformity...

A new Main Control Room for the AGS complex

International Nuclear Information System (INIS)

Ingrassia, P.F.; Zaharatos, R.M.; Dyling, O.H.

1991-01-01

A new Main Control Room (MCR) has been built to control the accelerators of the AGS Complex. A new physical environment was produced to better control light, sound, temperature, and traffic. New control consoles were built around the work-stations that make up the distributed control system. Equipment placement within consoles and console placement within the room reflect attention to the 'human factors' needs of the operator

MONITORING OF INDIVIDUAL DOSES FOR MEDICAL WORKERS OF DENTAL POLYCLINIC’S X-RAY ROOMS IN DUSHANBE, THE REPUBLIC OF TADJIKISTAN

Directory of Open Access Journals (Sweden)

N. U. Hakimova

2016-01-01

Full Text Available The article presents the data and analyses of personnel’s average annual external exposure doses monitoring via the thermoluminescent dosimetry method used for X-ray radiological personnel in dental polyclinics of Dushanbe, Tadjikistan Republic over a 5-year period ( 2010–2014 . Out of 42 registered medical institutions dental polyclinics amounted up to only just 14%. For this work thermoluminescent dosimeters were used ( with LiF: Mg, Ti with the thermoluminescent dosimetric installation “ Harshaw – 4500” as the reader device. Monitoring results comparison of individual dose equivalent Hp ( 10 values was conducted for two groups of medical workers: medical doctors and X-ray lab technicians. It is demonstrated that radiological technicians’ professional exposure doses are on the average by 23% higher than those for medical doctors.The average individual exposure doses over the above indicated period amount to 0,93 mSv and 1,3 mSv for doctors and X-ray lab technicians, respectively, and are in the range from 0,45 mSv to 2,39 mSv. The doses include contribution from the natural background. The values of doses recorded for the personnel in dental polyclinic correspond to those recorded for the workers in the routine X-ray rooms.

Engineering Process Monitoring for Control Room Operation

CERN Document Server

Bätz, M

2001-01-01

A major challenge in process operation is to reduce costs and increase system efficiency whereas the complexity of automated process engineering, control and monitoring systems increases continuously. To cope with this challenge the design, implementation and operation of process monitoring systems for control room operation have to be treated as an ensemble. This is only possible if the engineering of the monitoring information is focused on the production objective and is lead in close collaboration of control room teams, exploitation personnel and process specialists. In this paper some principles for the engineering of monitoring information for control room operation are developed at the example of the exploitation of a particle accelerator at the European Laboratory for Nuclear Research (CERN).

The MARS15-based FermiCORD code system for calculation of the accelerator-induced residual dose

Science.gov (United States)

Grebe, A.; Leveling, A.; Lu, T.; Mokhov, N.; Pronskikh, V.

2018-01-01

The FermiCORD code system, a set of codes based on MARS15 that calculates the accelerator-induced residual doses at experimental facilities of arbitrary configurations, has been developed. FermiCORD is written in C++ as an add-on to Fortran-based MARS15. The FermiCORD algorithm consists of two stages: 1) simulation of residual doses on contact with the surfaces surrounding the studied location and of radionuclide inventories in the structures surrounding those locations using MARS15, and 2) simulation of the emission of the nuclear decay γ-quanta by the residuals in the activated structures and scoring the prompt doses of these γ-quanta at arbitrary distances from those structures. The FermiCORD code system has been benchmarked against similar algorithms based on other code systems and against experimental data from the CERF facility at CERN, and FermiCORD showed reasonable agreement with these. The code system has been applied for calculation of the residual dose of the target station for the Mu2e experiment and the results have been compared to approximate dosimetric approaches.

Study of bremsstrahlung dose fields in radiation shield and labyrinth devices of plants with LUEH-8/5B accelerator

International Nuclear Information System (INIS)

Vikulin, A.A.; Vanyushkin, B.M.; Garnyk, D.V.; Kon'kov, N.G.; Terent'ev, B.M.

1980-01-01

Measurement results of exposure dose rate (EDR) of radiation in fields of bremsstrahlung of radiation plants with LUEh-8/5B linear accelerator of electrons by means of DRG2-03 dose meter, intended for operative measuring EDR in high intense fields of γ-radiation of powerful radioisotopic plants, are presented. Dose meter design is described. Measurements of bremsstrahlung EDR have been carried out in the chamber of plant irradiation for radiation sterilizing medical items, as well as in the chamber of VNIIRT experimental plant. RUP-1 device has been used for measuring radiation EDR in a labyrinth behind 1.8 m thick shoulder by concrete [ru

Effect of the new carbon fiber board of Elekta Precise linear accelerator on the radiation dose

International Nuclear Information System (INIS)

Gan Jiaying; Hu Yinxiang; Luo Yuanqiang; Hong Wei; Wang Zhiyong; Lu Bing; Jin Feng

2012-01-01

Objective: To investigate the dosimetric influence of pure carbon fiber treatment tabletop of Elekta Precise new linear accelerator in radiotherapy. Methods: Surface-axis distance (SAD) technology was employed for the measurement. Two groups of fields were set and both of them were SAD opposed portals (one of them went through the tabletop,while the other did not). A PTW electrometer and a 0.6 cm 3 Farmer ionization chamber were utilized for comparison measurement. Then dose attenuation of the main table board, extended body board, the extended board for head, neck and shoulders, and the joints of these boards were calculated. Results: Under the energy of 6 MV,the dose attenuations of the following locations were: 1.4% - 7.2% at the main treatment table board; 2.8% - 38.7%, 1.4% -30.1%, 1.5% -20.8% and 1.4% - 11.2%, respectively at distances of 1, 4, 7 and 8 cm from the joint of the main table board; 0.5% - 5.0% at the extended body board; 4.7% - 15.4% at distance of 1 cm from the joint of the extended body board; 0.5% -3.3% at the neck position of the extended board for head, neck and shoulders; 5.3% - 16.7% at the shoulder positions; and 6.8% -30.4% at the joint between the extended boards and the main table board. Conclusions: The dose attenuations of the new linear accelerator pure carbon fiber treatment tabletop vary at different locations. Considerable higher attenuations are observed at the table board joints than other locations. (authors)

Mechanistic insights into the room temperature transitions of polytetrafluoroethylene during electron-beam irradiation

Science.gov (United States)

Fu, Congli; Yu, Xianwei; Zhao, Xiaofeng; Wang, Xiuli; Gu, Aiqun; Xie, Meiju; Chen, Chen; Yu, Zili

2017-11-01

In order to recognize the characteristic thermal transitions of polytetrafluoroethylene (PTFE) occurring at 19 °C and 30 °C, PTFE is irradiated on electron beam accelerator at room temperature and analyzed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results suggest that the two transition temperatures decrease considerably with increasing irradiation doses. Based on the results of structural analysis, the decrease of the two transition temperatures is supposed to be highly relevant to the structural changes. In particular, the content and structure of the side groups generated in PTFE are responsible for the variations of the two thermal transitions after irradiation, offering fundamental insights into the reaction mechanisms of PTFE during irradiation.

Generation of ozone and safety aspects in an accelerator facility of BARC

International Nuclear Information System (INIS)

Dubey, Praveen; Sawatkar, Aparna R.; Sathe, Arun P.; Soundararajan, S.; Sarma, K.S.S.

2009-01-01

Industrial electron beam accelerators up to 10 MeV are commonly employed for different applications. During normal operation of an accelerator, the principal hazard is the high radiation level produced. Experiments and applications in which the electron beam is used to irradiate materials outside the accelerator vacuum system are associated with problems such as radiation damage and production of considerable quantities of ozone. The possible generation of ozone during the operation of an electron beam accelerator is of special interest due to reactivity, corrosivity and the toxic characteristics of ozone. Industrial hygiene surveys were conducted to estimate the airborne concentration of ozone during operations of the electron beam accelerator (Type: ILU-6; 2 MeV; 20 KW) at varied operating parameters. The ozone concentration in the accelerator room was measured at different powers of the accelerator and the ozone decay pattern was also observed after beam shut down. Ozone in the accelerator room was measured by different methods such as colorimetry using neutral buffered potassium iodide, chemiluminescence method using ethylene and by using electrochemical sensor. An air velocity meter was used to measure the linear air velocity across the exhaust grills and the number of air changes available in the accelerator room was calculated. Necessary control measures were suggested to keep the occupational exposure of the personnel to ozone concentrations well within the Threshold Limit Values. (author)

CEBAF Control Room Renovation

International Nuclear Information System (INIS)

Michael Spata; Thomas Oren

2005-01-01

The Machine Control Center (MCC) at Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) was initially constructed in the early 1990s and based on proven technology of that era. Through our experience over the last 15 years and in our planning for the facility's 12 GeV upgrade we reevaluated the control room environment to capitalize on emerging visualization and display technologies and improve workflow processes and ergonomic attributes. This effort also sets the foundation for the redevelopment of the accelerator's control system to deliver high reliability performance with improvements in beam specifications management and information flow. The complete renovation was performed over a three-week maintenance period with no interruption to beam operations. We present the results of this effort

CEBAF Control Room Renovation

International Nuclear Information System (INIS)

Michael Spata; Thomas Oren

2005-01-01

The Machine Control Center at Jefferson Lab's Continuous Electron Beam Accelerator Facility was initially constructed in the early 1990s and based on proven technology of that era. Through our experience over the last 15 years and in our planning for the facilities 12 GeV upgrade we reevaluated the control room environment to capitalize on emerging visualization and display technologies and improve on workflow processes and ergonomic attributes. This effort also sets the foundation for the redevelopment of the accelerator's control system to deliver high reliability performance with improvements in beam specifications management and information flow. The complete renovation was performed over a three-week period with no interruption to beam operations. We present the results of this effort

APT accelerator technology

International Nuclear Information System (INIS)

Schneider, J. David

1996-01-01

The proposed accelerator production of tritium (APT) project requires an accelerator that provides a cw proton beam of 100 m A at 1300 MeV. Since the majority of the technical risk of a high-current cw (continuous-wave, 100% DF) accelerator resides in the low-energy section, Los Alamos is building a 20 MeV duplicate of the accelerator front end to confirm design codes, beam performance, and demonstrate operational reliability. We report on design details of this low-energy demonstration accelerator (LEDA) and discuss the integrated design of the full accelerator for the APT plant. LEDA's proton injector is under test and has produced more than 130 mA at 75 keV. Fabrication is proceeding on a 6.7- MeV, 8-meter-long RFQ, and detailed design is underway on coupled-cavity drift-tube linac (CCDTL) structures. In addition, detailed design and technology experiments are underway on medium-beta superconducting cavities to assess the feasibility of replacing the conventional (room-temperature copper) high-energy linac with a linac made of niobium superconducting RF cavities. (author)

A GPU-accelerated Monte Carlo dose calculation platform and its application toward validating an MRI-guided radiation therapy beam model

International Nuclear Information System (INIS)

Wang, Yuhe; Mazur, Thomas R.; Green, Olga; Hu, Yanle; Li, Hua; Rodriguez, Vivian; Wooten, H. Omar; Yang, Deshan; Zhao, Tianyu; Mutic, Sasa; Li, H. Harold

2016-01-01

Purpose: The clinical commissioning of IMRT subject to a magnetic field is challenging. The purpose of this work is to develop a GPU-accelerated Monte Carlo dose calculation platform based on PENELOPE and then use the platform to validate a vendor-provided MRIdian head model toward quality assurance of clinical IMRT treatment plans subject to a 0.35 T magnetic field. Methods: PENELOPE was first translated from FORTRAN to C++ and the result was confirmed to produce equivalent results to the original code. The C++ code was then adapted to CUDA in a workflow optimized for GPU architecture. The original code was expanded to include voxelized transport with Woodcock tracking, faster electron/positron propagation in a magnetic field, and several features that make gPENELOPE highly user-friendly. Moreover, the vendor-provided MRIdian head model was incorporated into the code in an effort to apply gPENELOPE as both an accurate and rapid dose validation system. A set of experimental measurements were performed on the MRIdian system to examine the accuracy of both the head model and gPENELOPE. Ultimately, gPENELOPE was applied toward independent validation of patient doses calculated by MRIdian’s KMC. Results: An acceleration factor of 152 was achieved in comparison to the original single-thread FORTRAN implementation with the original accuracy being preserved. For 16 treatment plans including stomach (4), lung (2), liver (3), adrenal gland (2), pancreas (2), spleen(1), mediastinum (1), and breast (1), the MRIdian dose calculation engine agrees with gPENELOPE with a mean gamma passing rate of 99.1% ± 0.6% (2%/2 mm). Conclusions: A Monte Carlo simulation platform was developed based on a GPU- accelerated version of PENELOPE. This platform was used to validate that both the vendor-provided head model and fast Monte Carlo engine used by the MRIdian system are accurate in modeling radiation transport in a patient using 2%/2 mm gamma criteria. Future applications of this

A GPU-accelerated Monte Carlo dose calculation platform and its application toward validating an MRI-guided radiation therapy beam model.

Science.gov (United States)

Wang, Yuhe; Mazur, Thomas R; Green, Olga; Hu, Yanle; Li, Hua; Rodriguez, Vivian; Wooten, H Omar; Yang, Deshan; Zhao, Tianyu; Mutic, Sasa; Li, H Harold

2016-07-01

The clinical commissioning of IMRT subject to a magnetic field is challenging. The purpose of this work is to develop a GPU-accelerated Monte Carlo dose calculation platform based on penelope and then use the platform to validate a vendor-provided MRIdian head model toward quality assurance of clinical IMRT treatment plans subject to a 0.35 T magnetic field. penelope was first translated from fortran to c++ and the result was confirmed to produce equivalent results to the original code. The c++ code was then adapted to cuda in a workflow optimized for GPU architecture. The original code was expanded to include voxelized transport with Woodcock tracking, faster electron/positron propagation in a magnetic field, and several features that make gpenelope highly user-friendly. Moreover, the vendor-provided MRIdian head model was incorporated into the code in an effort to apply gpenelope as both an accurate and rapid dose validation system. A set of experimental measurements were performed on the MRIdian system to examine the accuracy of both the head model and gpenelope. Ultimately, gpenelope was applied toward independent validation of patient doses calculated by MRIdian's kmc. An acceleration factor of 152 was achieved in comparison to the original single-thread fortran implementation with the original accuracy being preserved. For 16 treatment plans including stomach (4), lung (2), liver (3), adrenal gland (2), pancreas (2), spleen(1), mediastinum (1), and breast (1), the MRIdian dose calculation engine agrees with gpenelope with a mean gamma passing rate of 99.1% ± 0.6% (2%/2 mm). A Monte Carlo simulation platform was developed based on a GPU- accelerated version of penelope. This platform was used to validate that both the vendor-provided head model and fast Monte Carlo engine used by the MRIdian system are accurate in modeling radiation transport in a patient using 2%/2 mm gamma criteria. Future applications of this platform will include dose validation and

A GPU-accelerated Monte Carlo dose calculation platform and its application toward validating an MRI-guided radiation therapy beam model

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuhe; Mazur, Thomas R.; Green, Olga; Hu, Yanle; Li, Hua; Rodriguez, Vivian; Wooten, H. Omar; Yang, Deshan; Zhao, Tianyu; Mutic, Sasa; Li, H. Harold, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

2016-07-15

Purpose: The clinical commissioning of IMRT subject to a magnetic field is challenging. The purpose of this work is to develop a GPU-accelerated Monte Carlo dose calculation platform based on PENELOPE and then use the platform to validate a vendor-provided MRIdian head model toward quality assurance of clinical IMRT treatment plans subject to a 0.35 T magnetic field. Methods: PENELOPE was first translated from FORTRAN to C++ and the result was confirmed to produce equivalent results to the original code. The C++ code was then adapted to CUDA in a workflow optimized for GPU architecture. The original code was expanded to include voxelized transport with Woodcock tracking, faster electron/positron propagation in a magnetic field, and several features that make gPENELOPE highly user-friendly. Moreover, the vendor-provided MRIdian head model was incorporated into the code in an effort to apply gPENELOPE as both an accurate and rapid dose validation system. A set of experimental measurements were performed on the MRIdian system to examine the accuracy of both the head model and gPENELOPE. Ultimately, gPENELOPE was applied toward independent validation of patient doses calculated by MRIdian’s KMC. Results: An acceleration factor of 152 was achieved in comparison to the original single-thread FORTRAN implementation with the original accuracy being preserved. For 16 treatment plans including stomach (4), lung (2), liver (3), adrenal gland (2), pancreas (2), spleen(1), mediastinum (1), and breast (1), the MRIdian dose calculation engine agrees with gPENELOPE with a mean gamma passing rate of 99.1% ± 0.6% (2%/2 mm). Conclusions: A Monte Carlo simulation platform was developed based on a GPU- accelerated version of PENELOPE. This platform was used to validate that both the vendor-provided head model and fast Monte Carlo engine used by the MRIdian system are accurate in modeling radiation transport in a patient using 2%/2 mm gamma criteria. Future applications of this

A new main control room for the AGS complex

International Nuclear Information System (INIS)

Ingrassia, P.F.; Zaharatos, R.M.; Dyling, O.H.

1991-01-01

A new Main Control Room (MCR) has been built to control the accelerators of the AGS Complex. A new physical environment was produced to better control light, sound, temperature, and traffic. New control consoles were built around the work-stations that make up the distributed control system. Equipment placement within consoles and console placement within the room reflect attention to the ''human factors'' needs of the operator. 1 ref., 2 figs

Study of factors controlling exposure dose and image quality of C-arm in operation room according to detector size of it (Mainly L-Spine AP study)

Energy Technology Data Exchange (ETDEWEB)

Chui, Sung Hyun; Jo, Hwang Woo [Dept. of Radiology, Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Chun, Woon Kwan; Song, Ha Jin [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of); Dong, Kyung Rae [Dept. of Radiological Technology, Gwangju Health University, Gwangju (Korea, Republic of); Choi, Eun Jin [Dept. of Public Health and Medicine, Dongshin University, Naju (Korea, Republic of)

2015-02-15

Time of operation has been reduced and accuracy of operation has been improved since C-arm, which offer real-time image of patient, was introduced in operation room. However, because of the contamination of patient, C-arm could not be used more appropriately. Therefore, this study is to know factors of controlling exposure dose, image quality and the exposed dose of health professional in operation room. Height of Wilson frame (bed for operation) was fixed at 130 cm. Then, Model 76-2 Phantom, which was set by assembling manual of Fluke Company, was set on the bed. Head/Spine Fluoroscopy AEC mode was set for exposure condition. According to detector size of C-arm, the absorbed dose per min was measured in the 7 steps OFD (cm) from 10 cm to 40 cm (10, 15, 20, 25, 30, 35, 40 cm). In each step of OFD, the absorbed dose per min of same diameter of collimation was measured. Moreover, using Nero MAX Model 8000, exposure dose per min was measured according to 3 step of distance from detector (20 cm, 60 cm, 100 cm). Finally, resolution was measured by CDRH Disc Phantom and magnification of each OFD was measured by aluminum stick bar. According to detector size of C-arm, difference of absorbed dose shows that the dose of 20 cm OFD is 1.750 times higher than the dose of 40 cm OFD. It means that the C-arm, which has smaller size of detector, shows the bigger difference of absorbed dose per min (p<0.05). In the difference of absorbed dose in the same step of OFD (from 20 cm to 40 cm), the absorbed dose of 9 inch detect or C-arm was 1.370 times higher than 12 inch' s (p<0.05). When OFD was set to 20 cm OFD, the absorbed dose of non-collimation case was approximately 0.816 times lower than the absorbed dose of collimation cases (p<0.05). When the distance was 20 cm from detector, exposed does includes first-ray and scatter-ray. When the distance was 60 cm and 100 cm from detector, exposed does includes just scatter-ray. So, there was the 2.200 times difference of absorbed

TU-F-CAMPUS-T-04: An Evaluation of Out-Of-Field Doses for Electron Beams From Modern Varian and Elekta Linear Accelerators

Energy Technology Data Exchange (ETDEWEB)

Cardenas, C; Nitsch, P; Kudchadker, R; Howell, R; Kry, S [UT MD Anderson Cancer Center, Houston, TX (United States)

2015-06-15

Purpose: Accurately determining out-of-field doses when using electron beam radiotherapy is of importance when treating pregnant patients or patients with implanted electronic devices. Scattered doses outside of the applicator field in electron beams have not been broadly investigated, especially since manufacturers have taken different approaches in applicator designs. Methods: In this study, doses outside of the applicator field were measured for electron beams produced by a 10×10 applicator on two Varian 21iXs operating at 6, 9, 12, 16, and 20 MeV, a Varian TrueBeam operating at 6, 9, 12, 16, and 20 MeV, and an Elekta Versa HD operating at 6, 9, 12 and 15 MeV. Peripheral dose profiles and percent depth doses were measured in a Wellhofer water phantom at 100 cm SSD with a Farmer ion chamber. Doses were compared to peripheral photon doses from AAPM’s Task Group #36 report. Results: Doses were highest for the highest electron energies. Doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. Substantial dose differences were observed between different accelerators; the Elekta accelerator had much higher doses than any Varian unit examined. Surprisingly, doses were often similar to, and could be much higher than, doses from photon therapy. Doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. Conclusion: The results of this study indicate that proper shielding may be very important when utilizing electron beams, particularly on a Versa HD, while treating pregnant patients or those with implanted electronic devices. Applying a water equivalent bolus of Emax(MeV)/4 thickness (cm) on the patient would reduce fetal dose drastically for all clinical energies and is a practical solution to manage the potentially high peripheral doses seen from modern electron beams. Funding from NIH Grant number: #CA180803.

New technologies for a postaccident control room habitability assessment

International Nuclear Information System (INIS)

Lahti, G.P.; Perchiazzi, W.T.

1993-01-01

Older nuclear power plants typically considered only a nominal amount of unfiltered in-leakage (typically 10 ft 3 /min) affecting their postaccident habitability. However, recent measurements of unfiltered in-leakage show leakages in excess of the nominal 10 ft 3 /m in. The assessment of postaccident doses in control rooms is done in a number of well-defined steps: (1) Determine the initial release of radioactivity to the containment (the open-quotes source termclose quotes). (2) Determine the release of radioactivity to the environment. (3) Determine the atmospheric dispersion and the concentration at the control room air intake. (4) Determine within-building dilution (if any). (5) Determine unfiltered in-leakage. (6) Determine the concentration of radioactivity in the control room. (7) Determine the dose to control room occupants. The prescriptive methodology of the Murphy-Campe paper and Standard Review Plan (SRP) 6.4 has been used by the U.S. Nuclear Regulatory Commission (NRC) to assess control room designs. However, a number of new technologies have been employed to reevaluate an existing pressurized water reactor plant design

Procedure to measure the neutrons spectrum around a lineal accelerator for radiotherapy

International Nuclear Information System (INIS)

Vega C, H. R.; Hernandez D, V. M.; Letechipia de L, C.; Benites R, J. L.; Salas L, M. A.

2013-10-01

An experimental procedure was developed, by means of Bonner spheres, to measure the neutrons spectrum around Linacs of medical use that only requires of a single shot of the accelerator; to this procedure we denominate Planetary or Isocentric method. One of the problems associated to the neutrons spectrum measurement in a radiotherapy room with lineal accelerator is because inside the room a mixed, intense and pulsed radiation field takes place affecting the detection systems based on active detector; this situation is solved using a passive detector. In the case of the Bonner spheres spectrometer the active detector has been substituted by activation detectors, trace detectors or thermoluminescent dosimeters. This spectrometer uses several spheres that are situated one at a time in the measurement point, this way to have the complete measurements group the accelerator should be operated, under the same conditions, so many times like spheres have the spectrometer, this activity can consume a long time and in occasions due to the work load of Linac to complicate the measurement process too. The procedure developed in this work consisted on to situate all the spectrometer spheres at the same time and to make the reading by means of a single shot, to be able to apply this procedure, is necessary that before the measurements two characteristics are evaluated: the cross-talking of the spheres and the symmetry conditions of the neutron field. This method has been applied to determine the photo-neutrons spectrum produced by a lineal accelerator of medical use Varian ix of 15 MV to 100 cm of the isocenter located to 5 cm of depth of a solid water mannequin of 30 x 30 x 15 cm. The spectrum was used to determine the total flow and the environmental dose equivalent. (Author)

Neutron induced activation in the EVEDA accelerator materials: Implications for the accelerator maintenance

International Nuclear Information System (INIS)

Sanz, J.; Garcia, M.; Sauvan, P.; Lopez, D.; Moreno, C.; Ibarra, A.; Sedano, L.

2009-01-01

The Engineering Validation and Engineering Design Activities (EVEDA) phase of the International Fusion Materials Irradiation Facility project should result in an accelerator prototype for which the analysis of the dose rates evolution during the beam-off phase is a necessary task for radioprotection and maintenance feasibility purposes. Important aspects of the computational methodology to address this problem are discussed, and dose rates for workers inside the accelerator vault are assessed and found to be not negligible.

Neutron induced activation in the EVEDA accelerator materials: Implications for the accelerator maintenance

Energy Technology Data Exchange (ETDEWEB)

Sanz, J. [Department of Power Engineering, Universidad Nacional de Educacion a Distancia (UNED), C/Juan del Rosal 12, 28040 Madrid (Spain); Institute of Nuclear Fusion, UPM, 28006 Madrid (Spain)], E-mail: jsanz@ind.uned.es; Garcia, M.; Sauvan, P.; Lopez, D. [Department of Power Engineering, Universidad Nacional de Educacion a Distancia (UNED), C/Juan del Rosal 12, 28040 Madrid (Spain); Institute of Nuclear Fusion, UPM, 28006 Madrid (Spain); Moreno, C.; Ibarra, A.; Sedano, L. [CIEMAT, 28040 Madrid (Spain)

2009-04-30

The Engineering Validation and Engineering Design Activities (EVEDA) phase of the International Fusion Materials Irradiation Facility project should result in an accelerator prototype for which the analysis of the dose rates evolution during the beam-off phase is a necessary task for radioprotection and maintenance feasibility purposes. Important aspects of the computational methodology to address this problem are discussed, and dose rates for workers inside the accelerator vault are assessed and found to be not negligible.

Combining Acceleration Techniques for Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction.

Science.gov (United States)

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2017-01-01

Over the past decade, image quality in low-dose computed tomography has been greatly improved by various compressive sensing- (CS-) based reconstruction methods. However, these methods have some disadvantages including high computational cost and slow convergence rate. Many different speed-up techniques for CS-based reconstruction algorithms have been developed. The purpose of this paper is to propose a fast reconstruction framework that combines a CS-based reconstruction algorithm with several speed-up techniques. First, total difference minimization (TDM) was implemented using the soft-threshold filtering (STF). Second, we combined TDM-STF with the ordered subsets transmission (OSTR) algorithm for accelerating the convergence. To further speed up the convergence of the proposed method, we applied the power factor and the fast iterative shrinkage thresholding algorithm to OSTR and TDM-STF, respectively. Results obtained from simulation and phantom studies showed that many speed-up techniques could be combined to greatly improve the convergence speed of a CS-based reconstruction algorithm. More importantly, the increased computation time (≤10%) was minor as compared to the acceleration provided by the proposed method. In this paper, we have presented a CS-based reconstruction framework that combines several acceleration techniques. Both simulation and phantom studies provide evidence that the proposed method has the potential to satisfy the requirement of fast image reconstruction in practical CT.

A high-power rf linear accelerator for FELS [free-electron lasers

International Nuclear Information System (INIS)

Sheffield, R.L.; Watson, J.M.

1987-01-01

This paper describes the design of a high average current rf linear accelerator suitable for driving short-wavelength free-electron lasers (FEL). It is concluded that the design of a room-temperature rf linear acelerator that can meet the stringent requirements of a high-power short-wavelength FEL appears possible. The accelerator requires the use of an advanced photoelectric injector that is under development; the accelerator components, however, do not require appreciable development. At these large beam currents, low-frequency, large-bore room-temperature cavities can be highly efficient and give all specified performance with minimal risk. 20 refs

A light-weight compact proton gantry design with a novel dose delivery system for broad-energetic laser-accelerated beams.

Science.gov (United States)

Masood, U; Cowan, T E; Enghardt, W; Hofmann, K M; Karsch, L; Kroll, F; Schramm, U; Wilkens, J J; Pawelke, J

2017-07-07

Proton beams may provide superior dose-conformity in radiation therapy. However, the large sizes and costs limit the widespread use of proton therapy (PT). The recent progress in proton acceleration via high-power laser systems has made it a compelling alternative to conventional accelerators, as it could potentially reduce the overall size and cost of the PT facilities. However, the laser-accelerated beams exhibit different characteristics than conventionally accelerated beams, i.e. very intense proton bunches with large divergences and broad-energy spectra. For the application of laser-driven beams in PT, new solutions for beam transport, such as beam capture, integrated energy selection, beam shaping and delivery systems are required due to the specific beam parameters. The generation of these beams are limited by the low repetition rate of high-power lasers and this limitation would require alternative solutions for tumour irradiation which can efficiently utilize the available high proton fluence and broad-energy spectra per proton bunch to keep treatment times short. This demands new dose delivery system and irradiation field formation schemes. In this paper, we present a multi-functional light-weight and compact proton gantry design for laser-driven sources based on iron-less pulsed high-field magnets. This achromatic design includes improved beam capturing and energy selection systems, with a novel beam shaping and dose delivery system, so-called ELPIS. ELPIS system utilizes magnetic fields, instead of physical scatterers, for broadening the spot-size of broad-energetic beams while capable of simultaneously scanning them in lateral directions. To investigate the clinical feasibility of this gantry design, we conducted a treatment planning study with a 3D treatment planning system augmented for the pulsed beams with optimizable broad-energetic widths and selectable beam spot sizes. High quality treatment plans could be achieved with such unconventional beam

A light-weight compact proton gantry design with a novel dose delivery system for broad-energetic laser-accelerated beams

Science.gov (United States)

Masood, U.; Cowan, T. E.; Enghardt, W.; Hofmann, K. M.; Karsch, L.; Kroll, F.; Schramm, U.; Wilkens, J. J.; Pawelke, J.

2017-07-01

Proton beams may provide superior dose-conformity in radiation therapy. However, the large sizes and costs limit the widespread use of proton therapy (PT). The recent progress in proton acceleration via high-power laser systems has made it a compelling alternative to conventional accelerators, as it could potentially reduce the overall size and cost of the PT facilities. However, the laser-accelerated beams exhibit different characteristics than conventionally accelerated beams, i.e. very intense proton bunches with large divergences and broad-energy spectra. For the application of laser-driven beams in PT, new solutions for beam transport, such as beam capture, integrated energy selection, beam shaping and delivery systems are required due to the specific beam parameters. The generation of these beams are limited by the low repetition rate of high-power lasers and this limitation would require alternative solutions for tumour irradiation which can efficiently utilize the available high proton fluence and broad-energy spectra per proton bunch to keep treatment times short. This demands new dose delivery system and irradiation field formation schemes. In this paper, we present a multi-functional light-weight and compact proton gantry design for laser-driven sources based on iron-less pulsed high-field magnets. This achromatic design includes improved beam capturing and energy selection systems, with a novel beam shaping and dose delivery system, so-called ELPIS. ELPIS system utilizes magnetic fields, instead of physical scatterers, for broadening the spot-size of broad-energetic beams while capable of simultaneously scanning them in lateral directions. To investigate the clinical feasibility of this gantry design, we conducted a treatment planning study with a 3D treatment planning system augmented for the pulsed beams with optimizable broad-energetic widths and selectable beam spot sizes. High quality treatment plans could be achieved with such unconventional beam

Shielding Design and Leaking Measurement for the High Energy Radiation Room

International Nuclear Information System (INIS)

Chu, Sung Sil

1979-01-01

An optimum shielding design and the computation of protective barriers for high energy radiation therapy room, Toshiba 13 MeV , are presented. We obtained following results by comparison between the p recalculating values and actual survey after complete installation of radio generating units. 1. The precalculating values of protective barrier are 5 times more protective than that of actual measurement. 2. The dose rate during exposure are 2-10 mR /hr at out of the door and the control room. 3. The exposure doses for occupationally persons are relatively low levels, the average values of exposure dose is 10-50 mR per month. 4. The foul smelling and ozone gas production from long exposure of cancer patients cannot be eliminated when the room is ill ventilated

Medical uses of accelerators

International Nuclear Information System (INIS)

Bradbury, J.N.

1981-01-01

A variety of particle accelerators have either potential or already demonstrated uses in connection with medically-related research, diagnosis, and treatment. For cancer radiotherapy, nuclear particles including protons, neutrons, heavy ions, and negative pi mesons have advantages compared to conventional radiations in terms of dose localization and/or biological effectiveness. Clinical evaluations of these particles are underway at a number of institutions. Accelerator-produced radionuclides are in widespread use for research and routine diagnostic purposes. Elemental analysis techniques with charged particles and neutrons are being applied to bone, blood, and other tissues. Finally, low-dose medical imaging can be accomplished with accelerated protons and heavy ions. The status and future of these programs are discussed

IAE pulsed electrostatic accelerator

International Nuclear Information System (INIS)

Afanas'ev, V.P.; Ganzhelyuk, M.L.; Kozlov, L.D.; Koltypin, E.A.; Molchanov, Yu.D.; Otroshchenko, G.A.; Yan'kov, G.B.

1976-01-01

The modernized pulse electrostatic accelerator using the klystron ion grouping and the beam interruption system prior to acceleration is described. The accelerator is modernized in order to improve parameters of a current pulse and to decrease the background in the measurement room. The ion beam of needed dimensions is obtained with the help of a high-frequency source and a beam grouping and deflection system. The general view of the beam grouping and deflection system is shown. The ion beam forming process is considered in detail. The modernized electrostatic accelerator permits to obtain a pulse current with a pulse length of 1.5 ns and an amplitude of 1.5 - 2 μA. With the repetition frequency of 2 MHz, the average target current is about 6 μA

Computer vision based room interior design

Science.gov (United States)

Ahmad, Nasir; Hussain, Saddam; Ahmad, Kashif; Conci, Nicola

2015-12-01

This paper introduces a new application of computer vision. To the best of the author's knowledge, it is the first attempt to incorporate computer vision techniques into room interior designing. The computer vision based interior designing is achieved in two steps: object identification and color assignment. The image segmentation approach is used for the identification of the objects in the room and different color schemes are used for color assignment to these objects. The proposed approach is applied to simple as well as complex images from online sources. The proposed approach not only accelerated the process of interior designing but also made it very efficient by giving multiple alternatives.

Shielding calculations for industrial 5/7.5MeV electron accelerators using the MCNP Monte Carlo Code

Science.gov (United States)

Peri, Eyal; Orion, Itzhak

2017-09-01

High energy X-rays from accelerators are used to irradiate food ingredients to prevent growth and development of unwanted biological organisms in food, and by that extend the shelf life of the products. The production of X-rays is done by accelerating 5 MeV electrons and bombarding them into a heavy target (high Z). Since 2004, the FDA has approved using 7.5 MeV energy, providing higher production rates with lower treatments costs. In this study we calculated all the essential data needed for a straightforward concrete shielding design of typical food accelerator rooms. The following evaluation is done using the MCNP Monte Carlo code system: (1) Angular dependence (0-180°) of photon dose rate for 5 MeV and 7.5 MeV electron beams bombarding iron, aluminum, gold, tantalum, and tungsten targets. (2) Angular dependence (0-180°) spectral distribution simulations of bremsstrahlung for gold, tantalum, and tungsten bombarded by 5 MeV and 7.5 MeV electron beams. (3) Concrete attenuation calculations in several photon emission angles for the 5 MeV and 7.5 MeV electron beams bombarding a tantalum target. Based on the simulation, we calculated the expected increase in dose rate for facilities intending to increase the energy from 5 MeV to 7.5 MeV, and the concrete width needed to be added in order to keep the existing dose rate unchanged.

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)

Discussion on control room habitability assessment

International Nuclear Information System (INIS)

Li Bing; Chen Yingying; Xiao Jun; Yang Duanjie; Cui Hao

2014-01-01

The discussion on control room envelope integrity, source term analysis in habitability assessments and other impact factors for dose consequence is provided combined with regulatory requirements and the current status of domestic NPPs. Considering that the infiltration is an important factor for control room habitability assessment, CRE integrity test should be performed to demonstrate the CRE's infiltration characteristics. The consequence assessment should be performed based on different DBAs and different pathways, such as pathways internal to the plant. (authors)

Comparative study of the parameters associated with quality control and absorbed dose in linear accelerators with (FF) and without (FFF) flattening filter

International Nuclear Information System (INIS)

Souza, Anderson Sorgatti de

2017-01-01

Teletherapy, radiation therapy with linear accelerators, for cancer treatment has being used for years with good clinical results.Since the 90's the removal of the flattening filter, item placed at the gantry of the machine, has shown better results for the treatment of some cancers thus being extensively studied. Treatments with Intensity Modulated Radiotherapy (IMRT) and Stereotaxic Radiotherapy (SRT) were more efficient without the flattening filter. Varian Oncology released the TrueBeam in 2012, a accelerator capable of operating with or without the flattening filter. The aim of this work is to access homogeneity of the percentage depth dose (PDP) and beam quality index (TPR20/10), two important parameters used in patient dose calculations. The data used for analysis were obtained with the Israelita Albert Einstein Hospital (HIAE), Real Portugues Hospital (RHP) and 3 more institutions located in the United States. The statistical data analysis allowed to observe the parameters behaviors. In general, they were very homogeneous, with errors smaller than 1% confirming the conformance of the TrueBeam accelerators. (author)

Fluence to Dose Equivalent Conversion Coefficients for Evaluation of Accelerator Radiation Environments

International Nuclear Information System (INIS)

Thomas, Ralph H.; Zeman, Gary H.

2001-01-01

The derivation of a set of conversion functions for the expression of neutron fluence measurements in terms of Effective Dose, E, is described. Four functions in analytical form are presented, covering the neutron energy range from 2.5 10-8 to 10+4 MeV, for the interpretation of fluence measurements in the typical irradiation conditions experienced around high-energy proton accelerators such as the Bevatron. For neutron energies below 200 MeV the analytical functions were modeled after the ISO and ROT conversion coefficients in ICRU 57. For neutron energies above 200 MeV, the analytical function was derived from an analysis of recent published data. Sample calculations using either the analytical expressions or the tabulated conversion coefficients from which the analytical expressions are derived show agreement to better than plus/minus 5%

A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

OpenAIRE

Daniel L Saenz; Bhudatt R Paliwal; John E Bayouth

2014-01-01

ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This ...

Accelerators for therapy

International Nuclear Information System (INIS)

Pohlit, W.

1994-01-01

In the past decades circular and linear electron accelerators have been developed for clinical use in radiation therapy of tumors with the aim of achieving a high radiation dose in the tumor and as low as possible dose in the adjacent normal tissues. Today about one thousand accelerators are in medical use throughout the world and many hundred thousand patients are treated every day with accelerator-produced radiation. There exists, however, a large number of patients who cannot be treated satisfactorily in this way. New types of radiations such as neutrons, negative pions, protons and heavy ions were therefore tested recently. The clinical experience with these radiations and with new types of treatment procedures indicate that in future the use of a scanning beam of high energy protons might be optimal for the treatment of tumors. (orig.)

Evolution of calculation models for the proton-therapy dose planning software

International Nuclear Information System (INIS)

Vidal, Marie

2011-01-01

This work was achieved in collaboration between the Institut Curie Proton-therapy Center of Orsay (ICPO), the DOSIsoft company and the CREATIS laboratory, in order to develop a new dose calculation model for the new ICPO treatment room. A new accelerator and gantry room from the IBA company were installed during the up-grade project of the proton-therapy center, with the intention of enlarging the cancer localizations treated at ICPO. Developing a package of methods and new dose calculation algorithms to adapt them to the new specific characteristics of the delivered beams by the IBA system is the first goal of this PhD work. They all aim to be implemented in the DOSIsoft treatment planning software, Isogray. First, the double scattering technique is treated in taking into account major differences between the IBA system and the ICPO fixed beam lines passive system. Secondly, a model is explored for the scanned beams modality. The second objective of this work is improving the Ray-Tracing and Pencil-Beam dose calculation models already in use. For the double scattering and uniform scanning techniques, the patient personalized collimator at the end of the beam line causes indeed a patient dose distribution contamination. A reduction method of that phenomenon was set up for the passive beam system. An analytical model was developed which describes the contamination function with parameters validated through Monte-Carlo simulations on the GATE platform. It allows us to apply those methods to active scanned beams. (author) [fr

Simulation of lung cancer treatment with equivalent dose calculation and analysis of the dose distribution profile

International Nuclear Information System (INIS)

Thalhofer, J. L.; Marques L, J.; Da Silva, A. X.; Dos Reis J, J. P.; Da Silva J, W. F. R.; Arruda C, S. C.; Monteiro de S, E.; Santos B, D. V.

2017-10-01

Actually, lung cancer is one of the most lethal types, due to the disease in the majority of the cases asymptomatic in the early stages, being the detection of the pathology in advanced stage, with tumor considerable volume. Dosimetry analysis of healthy organs under real conditions is not feasible. Therefore, computational simulations are used to auxiliary in dose verification in organs of patients submitted to radiotherapy. The goal of this study is to calculate the equivalent dose, due to photons, in surrounding in healthy organs of a patient submitted to radiotherapy for lung cancer, through computational modeling. The simulation was performed using the MCNPX code (Version, 2006], Rex and Regina phantom [ICRP 110, 2008], radiotherapy room, Siemens Oncor Expression accelerator operating at 6 MV and treatment protocol adopted at the Inca (National Cancer Institute, Brazil). The results obtained, considering the dose due to photons for both phantom indicate that organs located inside the thoracic cavity received higher dose, being the bronchi, heart and esophagus more affected, due to the anatomical positioning. Clinical data describe the development of bronchiolitis, esophagitis, and cardiomyopathies with decreased cardiopulmonary function as one of the major effects of lung cancer treatment. In the Regina phantom, the second largest dose was in the region of the breasts with 615,73 mSv / Gy, while in the Rex 514,06 mSv / Gy, event related to the difference of anatomical structure of the organ. Through the t mesh command, a qualitative analysis was performed between the dose deposition profile of the planning system and the simulated treatment, with a similar profile of the dose distribution being verified along the patients body. (Author)

CNSTN Accelerator

International Nuclear Information System (INIS)

Habbassi, Afifa; Trabelsi, Adel

2010-01-01

This project give a big idea about the measurement of the linear accelerator in the CNSTN. During this work we control dose distribution for different product. For this characterisation we have to make an installation qualification ,operational qualification,performance qualification and of course for every step we have to control temperature and the dose ,even the distribution of the last one.

Dose-mapping distribution around MNSR

CERN Document Server

Jamal, M H

2002-01-01

The aim of this study is to establish the dose-rate map through the determination of radiological dose-rate levels in reactor hall, adjacent rooms, and outside the MNSR facility. Controlling dose rate to reactor operating personnel , dose map was established. The map covers time and distances in the reactor hall, during reactor operation at nominal power. Different measurement of dose rates in other areas of the reactor buildings was established. The maximum dose rate, during normal operation of the MNSR was 40 and 21 Sv/hr on the top of the reactor and near the pool fence, respectively. Whereas, gamma and neutron doses have not exceeded natural background in all rooms adjacent to the reactor hall or nearly buildings. The relation between the dose rate for gamma rays and neutron flux at the top of cover of reactor pool was studied as well. It was found that this relation is linear.

Dose-mapping distribution around MNSR

International Nuclear Information System (INIS)

Jamal, M. H.; Khamis, I.

2002-12-01

The aim of this study is to establish the dose-rate map through the determination of radiological dose-rate levels in reactor hall, adjacent rooms, and outside the MNSR facility. Controlling dose rate to reactor operating personnel , dose map was established. The map covers time and distances in the reactor hall, during reactor operation at nominal power. Different measurement of dose rates in other areas of the reactor buildings was established. The maximum dose rate, during normal operation of the MNSR was 40 and 21 Sv/hr on the top of the reactor and near the pool fence, respectively. Whereas, gamma and neutron doses have not exceeded natural background in all rooms adjacent to the reactor hall or nearly buildings. The relation between the dose rate for gamma rays and neutron flux at the top of cover of reactor pool was studied as well. It was found that this relation is linear. (author)

Measured Neutron Spectra and Dose Equivalents From a Mevion Single-Room, Passively Scattered Proton System Used for Craniospinal Irradiation

Energy Technology Data Exchange (ETDEWEB)

Howell, Rebecca M., E-mail: rhowell@mdanderson.org [Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Burgett, Eric A.; Isaacs, Daniel [Department of Nuclear Engineering, Idaho State University, Pocatello, Idaho (United States); Price Hedrick, Samantha G.; Reilly, Michael P.; Rankine, Leith J.; Grantham, Kevin K.; Perkins, Stephanie; Klein, Eric E. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States)

2016-05-01

Purpose: To measure, in the setting of typical passively scattered proton craniospinal irradiation (CSI) treatment, the secondary neutron spectra, and use these spectra to calculate dose equivalents for both internal and external neutrons delivered via a Mevion single-room compact proton system. Methods and Materials: Secondary neutron spectra were measured using extended-range Bonner spheres for whole brain, upper spine, and lower spine proton fields. The detector used can discriminate neutrons over the entire range of the energy spectrum encountered in proton therapy. To separately assess internally and externally generated neutrons, each of the fields was delivered with and without a phantom. Average neutron energy, total neutron fluence, and ambient dose equivalent [H* (10)] were calculated for each spectrum. Neutron dose equivalents as a function of depth were estimated by applying published neutron depth–dose data to in-air H* (10) values. Results: For CSI fields, neutron spectra were similar, with a high-energy direct neutron peak, an evaporation peak, a thermal peak, and an intermediate continuum between the evaporation and thermal peaks. Neutrons in the evaporation peak made the largest contribution to dose equivalent. Internal neutrons had a very low to negligible contribution to dose equivalent compared with external neutrons, largely attributed to the measurement location being far outside the primary proton beam. Average energies ranged from 8.6 to 14.5 MeV, whereas fluences ranged from 6.91 × 10{sup 6} to 1.04 × 10{sup 7} n/cm{sup 2}/Gy, and H* (10) ranged from 2.27 to 3.92 mSv/Gy. Conclusions: For CSI treatments delivered with a Mevion single-gantry proton therapy system, we found measured neutron dose was consistent with dose equivalents reported for CSI with other proton beamlines.

Accelerator Physics for ILC and CLIC

CERN Document Server

Zimmermann, F

2010-01-01

This paper summarizes the second part of the “accelerator physics lectures” delivered at the Ambleside Linear Collider School 2009. It discusses more specific linear-collider issues: superconducting and room-temperature linear accelerators, particle sources for electrons and positrons, synchrotron radiation and damping, intensity limits, beam stability, and beam delivery system – including final focus, collimation, and beam-beam effects. It also presents an overview of the International Linear Collider (ILC), a description of the two beam acceleration scheme of the Compact Linear Collider (CLIC), and a comparison of the ILC and CLIC parameters.

Monte Carlo study of in-field and out-of-field dose distributions from a linear accelerator operating with and without a flattening-filter

International Nuclear Information System (INIS)

Almberg, S. S.; Frengen, J.; Lindmo, T.

2012-01-01

Purpose: To compare dosimetric characteristics of 6 MV photon fields originating from a linear accelerator operating with (FF) and without (FFF) a flattening-filter. The main objective is to establish a FFF model that results in similar depth-dose and build-up profiles as the original FF model, and subsequently estimate and compare out-of-field dose distributions. Methods: The EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc are used for photon beam simulations of an Elekta linear accelerator and dose calculations in a water phantom, respectively. Three beam models were analyzed: (1) the conventional linear accelerator with the flattening-filter in place and incident electron energy 6.45 MeV (FF 6.45 MeV), (2) similar flattening-filter-free model (FFF 6.45 MeV), and (3) as (2) but with increased electron energy (FFF 8.0 MeV). The field size 5 × 5 cm 2 was used for characterization of dose output, depth dose profiles, and photon spectrum. The field size 40 × 40 cm 2 was used for characterization of cross-field photon energy, photon fluence, and dose distributions. Out-of-field dose distributions were analyzed in both in-plane and cross-plane directions for 5 × 5 cm 2 and 10 × 10 cm 2 fields. Results: Comparable depth dose distributions, including the build-up region, for FF and FFF fields were achieved by increasing the electron energy from 6.45 MeV to 8.0 MeV for the FFF beam. The FFF beams result in reduced out-of-field dose compared to the FF beam: the reduction was most apparent in the cross-plane direction and more pronounced by the FFF 8.0 MeV beam compared to the FFF 6.45 MeV beam. Differences in out-of-field dose due to direction (in-plane vs cross-plane) were up to 40% for the FF beam; this effect was significantly reduced for the FFF beams. As the flattening-filter is a major source of contaminating electrons, superficial out-of-field dose was expected, and was found to be, reduced for FFF beams. Conclusions: The build-up and depth-dose

Monte Carlo study of in-field and out-of-field dose distributions from a linear accelerator operating with and without a flattening-filter.

Science.gov (United States)

Almberg, S S; Frengen, J; Lindmo, T

2012-08-01

To compare dosimetric characteristics of 6 MV photon fields originating from a linear accelerator operating with (FF) and without (FFF) a flattening-filter. The main objective is to establish a FFF model that results in similar depth-dose and build-up profiles as the original FF model, and subsequently estimate and compare out-of-field dose distributions. The EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc are used for photon beam simulations of an Elekta linear accelerator and dose calculations in a water phantom, respectively. Three beam models were analyzed: (1) the conventional linear accelerator with the flattening-filter in place and incident electron energy 6.45 MeV (FF 6.45 MeV), (2) similar flattening-filter-free model (FFF 6.45 MeV), and (3) as (2) but with increased electron energy (FFF 8.0 MeV). The field size 5 × 5 cm(2) was used for characterization of dose output, depth dose profiles, and photon spectrum. The field size 40 × 40 cm(2) was used for characterization of cross-field photon energy, photon fluence, and dose distributions. Out-of-field dose distributions were analyzed in both in-plane and cross-plane directions for 5 × 5 cm(2) and 10 × 10 cm(2) fields. Comparable depth dose distributions, including the build-up region, for FF and FFF fields were achieved by increasing the electron energy from 6.45 MeV to 8.0 MeV for the FFF beam. The FFF beams result in reduced out-of-field dose compared to the FF beam: the reduction was most apparent in the cross-plane direction and more pronounced by the FFF 8.0 MeV beam compared to the FFF 6.45 MeV beam. Differences in out-of-field dose due to direction (in-plane vs cross-plane) were up to 40% for the FF beam; this effect was significantly reduced for the FFF beams. As the flattening-filter is a major source of contaminating electrons, superficial out-of-field dose was expected, and was found to be, reduced for FFF beams. The build-up and depth-dose characteristics of a conventional "6 MV" beam

Accelerated Near-Threshold Fatigue Crack Growth Behavior of an Aluminum Powder Metallurgy Alloy

Science.gov (United States)

Piascik, Robert S.; Newman, John A.

2002-01-01

Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low DK, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels of Kmax (Kmax less than 0.4 KIC). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and Kmax influenced accelerated crack growth is time and temperature dependent.

Working conditions of a radiodiagnostic room

International Nuclear Information System (INIS)

Chikirdin, Eh.G.

1983-01-01

The concept of ''operating load'' of an X-ray diagnostic room is explained. The concept includes the calculation of the Week's maximum exposure calculation and monitoring of stationary radiation shielding, measurements of exposure dose rate at working places. In this case the substitution of the actual repeated short-time regime of emitter operation for the calculated continuous regime is performed. The data on the ''operating load'' of X-ray diagnostic room are presented taking into account the method of X-ray investigation

Results of LIA-10M accelerator investigations

CERN Document Server

Gordeev, V S; Filippov, V O

2001-01-01

There are presented basic results of experiments on the LIA-10M accelerator since its putting into operation (1994) till today. There were investigated various modes of accelerator operation and its output characteristics depending on the parameters of injected electron beam,number of connected accelerator modules,time program of inductors switch-in etc. There was obtained a large scope of experimental data that are of interest for LIA-10M accelerator practical use and for the development of new facilities of this type. The investigations that have been performed recently make it possible to considerably (half as much again) increase the output dose parameters of the accelerator as compared to the level achieved before:maximal dose(Si) and dose rate on the output flange constitute 400 Gy and 2.5 centre dot 10 Gy/s, while at a 1 meter distance from the target they are equal to 7.5 Gy and 5 centre dot 10 sup 8 Gy/s, respectively.

SU-E-T-568: Neutron Dose Survey of a Compact Single Room Proton Machine

Energy Technology Data Exchange (ETDEWEB)

Chen, Y; Prusator, M; Islam, M; Johnson, D; Ahmad, S [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

2015-06-15

Purpose: To ensure acceptable radiation limits are maintained for those working at and near the machine during its operation, a comprehensive radiation survey was performed prior to the clinical release of Mevion S250 compact proton machine at Stephenson Oklahoma Cancer Center. Methods: The Mevion S250 proton therapy system consists of the following: a superconducting cyclotron to accelerate the proton particles, a passive double scattering system for beam shaping, and paired orthogonal x-ray imaging systems for patient setup and verification via a 6D robotic couch. All equipment is housed within a single vault of compact design. Two beam delivery applicators are available for patient treatment, offering field sizes of as great as 14 cm and 25 cm in diameter, respectively. Typical clinical dose rates are between 1 and 2 Gy/min with a fixed beam energy of 250 MeV. The large applicator (25 cm in diameter) was used in conjunction with a custom cut brass aperture to create a 20 cm x 20 cm field size at beam isocenter. A 30 cm − 30 cm − 35 cm high density plastic phantom was placed in the beam path to mimic the conditions creating patient scatter. Measurements integrated-ambient-neutron-dose-equivalence were made with a SWENDII detector. Gantry angles of 0, 90 and 180 degrees, with a maximum dose rate of 150 MU/min (for large applicator) and beam configuration of option 1 (range 25 cm and 20 cm modulation), were selected as testing conditions. At each point of interest, the highest reading was recorded at 30 cm from the barrier surface. Results: The highest neutron dose was estimated to be 0.085 mSv/year at the console area. Conclusion: All controlled areas are under 5 mSv/year and the uncontrolled areas are under 1 mSv/year. The radiation protection provided by the proton vault is of sufficient quality.

Simulated versus realistic intra operative radiation therapy (I.O.R.T.) treatment in operating room: from knowledge of stray radiation to action

International Nuclear Information System (INIS)

Andreoli, S.; Moretti, R.; Catalano, M.; Locatelli, F.

2006-01-01

Intra-Operative Radiation Therapy (I.O.R.T.) is carried out with electron beams produced by a Linac (Linear Accelerator) generally used for conventional radiotherapy with external beam, or by dedicated accelerators that can be employed directly into an operating room. I.O.R.T. refers to the application of radiation during a surgical intervention, after the removal of a neoplastic mass. I.O.R.T. uses on the tumour area a direct irradiation, for the possible localisation of sub-clinic illness or macroscopic residue in the case of non-radical resection. Intra-Operative Radiotherapy foresees a single session only, generally preceded or followed by radiotherapy with external beam. It allows the achievement of a selective radiation boost on the tumour volume. In some cases, it can also be used as a one-time/stand alone treatment in initial cancer of small volume, or in unresectable malignancies for palliative purpose. The technical advantages of I.O.R.T. consist in the direct visual control of the target volume, and in the possibility to protect the healthy tissues by moving them away from the path of the radiation beam. The use of electron beams allows the administration of a homogeneous dose to a selected layer of tissues surrounding the tumour. The following professional staff forms the Operative Group: radiation oncologist, surgeon, anaesthetist, medical physicist, radiation technologist, nurse.The choice of a simulation geometry very similar to the clinical situation allows to evaluate radioprotection data very close to the real situation. For a fixed layout, an anthropomorphic phantom was positioned on the operating bed and a breast I.O.R.T. treatment was simulated positioning all the accessories of the operating room in their typical positions. A detailed dose mapping was performed with a Victoreen 450P ionisation chamber and with environment film-dosimeter on the walls of the operating room during the simulation of the clinical treatment. The simulation appears

Physics design of an accelerator for an accelerator-driven subcritical system

Directory of Open Access Journals (Sweden)

Zhihui Li

2013-08-01

Full Text Available An accelerator-driven subcritical system (ADS program was launched in China in 2011, which aims to design and build an ADS demonstration facility with the capability of more than 1000 MW thermal power in multiple phases lasting about 20 years. The driver linac is defined to be 1.5 GeV in energy, 10 mA in current and in cw operation mode. To meet the extremely high reliability and availability, the linac is designed with much installed margin and fault tolerance, including hot-spare injectors and local compensation method for key element failures. The accelerator complex consists of two parallel 10-MeV injectors, a joint medium-energy beam transport line, a main linac, and a high-energy beam transport line. The superconducting acceleration structures are employed except for the radio frequency quadrupole accelerators (RFQs which are at room temperature. The general design considerations and the beam dynamics design of the driver linac complex are presented here.

An accelerator neutron source for BNCT. Technical progress report, 1 June 1993--31 May 1994

International Nuclear Information System (INIS)

Blue, T.E.; Vafai, K.

1994-02-01

This is the progress report for the project entitled, ''An Accelerator Neutron Source for BNCT.'' The progress report is for the period from July 1, 1993 to date. The overall objective of our research project is to develop an Accelerator Epithermal Neutron Irradiation Facility (AENIF) for Boron Neutron Capture Therapy (BNCT). The AENIF consists of a 2.5 MeV high current proton accelerator, a lithium target to produce source neutrons, and a moderator/reflector assembly to obtain from the energetic source neutrons an epithermal neutron field suitable for BNCT treatments. Our project goals are to develop the non-accelerator components of the AENIF, and to specifically include in our development: (1) design, numerical simulation, and experimental verification of a target assembly which is capable of removing 75 kW of beam power; (2) re-optimization of the moderator assembly design based on in-phantom dose assessments using neutron spectra calculated in phantom and an energy-dependent neutron Relative Biological Effectiveness (RBE); (3) construction of a prototype moderator assembly and confirmation of its design by measurements; (4) design of the shielding of the accelerator and treatment rooms for an AENIF; and (5) design of a high energy beam transport system which is compatible with the shielding design and the thermal-hydraulic design

Controlled platform for the radiation dose data measured in Radiation controlled area of KOMAC

International Nuclear Information System (INIS)

Park, Sung Kyun; Min, Yi Sub; Park, Jeong Min; Cho, Yong Sub

2016-01-01

Korea multi-purpose accelerator complex (KOMAC), the branch institute of Korea atomic energy research institute (KAERI), is a multi-user facility to provide a high-intensity proton beam with the energy from 20 MeV to the 100 MeV. This proton beam is accelerated via the proton linear accelerator that is comprised of a 50-keV injector, 3-MeV radio frequency quadrupole (RFQ), and 100-MeV drift tube linac (DTL). The KOMAC site is classified into General public area and Radiation controlled area, according to the dose rate of 0.25 μSv/h. The system for the data made in Radiation controlled area should have the database to save and the data in the database could be expressed on the monitor in the any form which user wants. The control platform to satisfy these conditions will be made on the basis of the Qt program and MYSQL program. The place with the maximum average values about the alpha and beta detected is the entrance of Radiation controlled area. However, their values are very small in comparison to the criteria to decide the contamination area in KOMAC. That is, KOMAC is safe from the radioactive contamination. The reason why the radiation dose value is twice the background value in Klystron gallery is the klystron to generate the radiation. However, actually the klystron gallery is controlled by the control room when the proton beam is accelerated

Controlled platform for the radiation dose data measured in Radiation controlled area of KOMAC

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Kyun; Min, Yi Sub; Park, Jeong Min; Cho, Yong Sub [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Korea multi-purpose accelerator complex (KOMAC), the branch institute of Korea atomic energy research institute (KAERI), is a multi-user facility to provide a high-intensity proton beam with the energy from 20 MeV to the 100 MeV. This proton beam is accelerated via the proton linear accelerator that is comprised of a 50-keV injector, 3-MeV radio frequency quadrupole (RFQ), and 100-MeV drift tube linac (DTL). The KOMAC site is classified into General public area and Radiation controlled area, according to the dose rate of 0.25 μSv/h. The system for the data made in Radiation controlled area should have the database to save and the data in the database could be expressed on the monitor in the any form which user wants. The control platform to satisfy these conditions will be made on the basis of the Qt program and MYSQL program. The place with the maximum average values about the alpha and beta detected is the entrance of Radiation controlled area. However, their values are very small in comparison to the criteria to decide the contamination area in KOMAC. That is, KOMAC is safe from the radioactive contamination. The reason why the radiation dose value is twice the background value in Klystron gallery is the klystron to generate the radiation. However, actually the klystron gallery is controlled by the control room when the proton beam is accelerated.

Progress Toward NLC/GLC Prototype Accelerator Structures

International Nuclear Information System (INIS)

Wang, J

2004-01-01

The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and design of HOM couplers and fundamental mode couplers, optimized accelerator cavities as well as plans for future structures

Determination of dose factors for external gamma radiation in dwellings

International Nuclear Information System (INIS)

Maduar, M.F.; Hiromoto, G.

2000-01-01

A significant contribution to the global population exposure to ionizing radiation arises from natural sources, especially from radionuclides present in terrestrial crust. Human activities can eventually increase that exposure to significant levels, from the point of view of radiological protection. The presence of natural radionuclides in building materials may lead to an increment of both external and internal radiation exposure of the population. External exposure in dwellings arises from gamma-emitter radionuclides existing in the walls, floor and ceiling of their rooms. Mathematical models can be used to predict external dose rates inside the room, known the radionuclide concentration activities in dwelling constituents. This paper presents a methodology for theoretical evaluation of external gamma doses due to radionuclides present in the walls of an hypothetical standard room. The room is modeled as three pairs of rectangular sheets with finite thickness. Assessment of doses was performed through the application of photon transport model, taking in account self-absorption and radiation buildup. As the external dose due to a particular radionuclide is proportional to its activity concentration, results are presented as dose factors, defined as a ratio of absorbed dose (nGy.h -1 ) to the activity concentration (Bq.kg -1 ), for each radionuclide. The radionuclides were assumed to be uniformly distributed in the building materials. Calculations were performed for concrete walls and results are presented for 40 K, 226 Ra, and 232 Th, taking in account, for dose calculations, all gamma emitters from 226 Ra and 232 Th decay chains. Sensitivity of the model was estimated by varying four of its input parameters within a reasonable range of applicability, while leaving all other parameters at fixed selected values. The parameters studied and respective ranges of variation were: for thickness, 5 to 60 cm; for density, 0.5 to 4 g.cm -3 ; for the room length, 1.5 to 10 m

Modernisation of Radiation Monitoring Room as a Part of Slovenian Emergency Response Centre

International Nuclear Information System (INIS)

Sarvari, A.; Mitic, D.

2003-01-01

In the year 2002 the Slovenian Nuclear Safety Administration (SNSA) moved to the new premises therefore it had to rearrange some of its rooms for the emergency situation. SNSA does not operate with a dedicated Emergency Response Centre (ERC), instead of it the SNSA has to rearrange the existing rooms in case of an emergency. Modernisation of the equipment, with the help of government of the United Kingdom of Great Britain and Northern Ireland, for the emergency situation was carried out, especially in the monitoring room. The radiation monitoring system, which is placed in the monitoring room, continuously collects, processes and archives the incoming data of exposure to radiation and meteorological parameters on the Slovenian territory (A model national emergency response plan for radiological accidents, IAEA, Vienna, 1993. IAEA-TECDOC-718). In the emergency situation the monitoring room transforms into the room for the Dose Assessment Group (DAG), which is part of ERC (IAEA emergency response network, IAEA, Vienna, 2000, EPR-ERNET (2000)). The modernisation of monitoring room and within the DAG room with new equipment and its purpose is described in this article. Modernisation of the monitoring room and the room for DAG showed to be inevitably needed. Modernisation of the monitoring room has brought the SNSA a sophisticated and reliable system of controlling the external exposure to radiation on the Slovenian territory. The equipment, especially the equipment for the use in the emergency situation, brought novelties for the Dose Assessment Group. The group has now better and easier control of radiation situation in case of an accident. In overall this modernisation has put the Slovenian Nuclear Safety Administration a step forward in having a dedicated Emergency Response Centre, since it does not need to rearrange the room for the Dose Assessment Group. (author)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Problems related to design and construction of industrial radiography exposure room - an experience

International Nuclear Information System (INIS)

Siti Madiha Muhammad Amir; Mohd Khairi Mohd Said; Abdul Nassir Ibrahim; Ab Razak Hamzah

2009-01-01

In Non-Destructive Testing (NDT), especially in radiography method, inspections of components are executed either on-site or in-house. For in-house inspections, work must be performed in a specially constructed exposure room. The design of the exposure room must be according to specific requirements described in various documents related to radiation safety. Stringent requirements specified for the exposure room is for the purpose of ensuring the safety of public and radiation workers. These requirements are never compromised. One of the AELB requirements that need to be complied is that the permissible dose limit anywhere outside the room must be less than 0.25 mR/hr. In designing and constructing the exposure room, many factors must be taken into account such as shielding thickness, density of shielding, thickness of lead door, the roof design of the exposure room and many more. This paper highlights problems encountered and the considerations taken to design and construct the exposure room so that the exposure room will comply with the permissible dose limit set by the regulatory body. (Author)

Advanced accelerator and mm-wave structure research at LANL

Energy Technology Data Exchange (ETDEWEB)

Simakov, Evgenya Ivanovna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-06-22

This document outlines acceleration projects and mm-wave structure research performed at LANL. The motivation for PBG research is described first, with reference to couplers for superconducting accelerators and structures for room-temperature accelerators and W-band TWTs. These topics are then taken up in greater detail: PBG structures and the MIT PBG accelerator; SRF PBG cavities at LANL; X-band PBG cavities at LANL; and W-band PBG TWT at LANL. The presentation concludes by describing other advanced accelerator projects: beam shaping with an Emittance Exchanger, diamond field emitter array cathodes, and additive manufacturing of novel accelerator structures.

A study on the reliability evaluation of shot peened aluminium alloy using accelerated life test

International Nuclear Information System (INIS)

Nam, Ji Hun; Cheong, Seong Kyun; Kang, Min Woo

2006-01-01

In this paper, the concept of accelerated life test, which is a popular research field nowadays, is applied to the shot peened material. To predict the efficient and exact room temperature fatigue characteristics from the high temperature fatigue data, the adequate accelerated model is investigated. Ono type rotary bending fatigue tester and high temperature chamber were used for the experiment. Room temperature fatigue lives were predicted by applying accelerated models and doing reliability evaluation. Room temperature fatigue tests were accomplished to check the effectiveness of predicted data and the adequate accelerated life test models were presented by considering errors. Experimental result using Arrhenius model, fatigue limit obtain almost 5.45% of error, inverse power law has about 1.36% of error, so we found that inverse power law is applied well to temperature-life relative of shot peended material

Accelerated Hypertension after Venlafaxine Usage

Directory of Open Access Journals (Sweden)

Yüksel Kıvrak

2014-01-01

Full Text Available Venlafaxine is the first antidepressant that acts via inhibiting serotonin and noradrenaline reuptake. Hypertension is observed in doses exceeding 300 mg/day and is the most feared complication. We report a patient with accelerated hypertension after venlafaxine use observed at a dose of 150 mg/day. A 23-year-old patient with symptoms of insomnia, depression, anhedonia, fatigue admitted our clinic. Venlafaxine at a dose of 75 mg/day was initiated after he was diagnosed with major depressive disorder. After 5 months, venlafaxine dose was uptitrated to 150 mg/day due to inadequate response to drug. After using venlafaxine for ten months at the dose of 150 mg/day, he admitted our clinic with headache and epistaxis. He was hospitalized after his blood pressure was measured as 210/170 mmHg. No secondary causes for hypertension were found, and venlafaxine treatment was considered possible etiologic factor. After stopping venlafaxine treatment, his blood pressure was reverted back to normal limits. While mild elevation of blood pressure could be observed after venlafaxine treatment, this case shows that accelerated hypertension with a diastolic blood pressure rise above 120 mmHg could be observed at relatively low doses of venlafaxine. Close monitoring of blood pressure is necessary after initiation of treatment, as accelerated hypertension could cause endorgan damage with potentially catastrophic results.

Radiation shielding design of BNCT treatment room for D-T neutron source.

Science.gov (United States)

Pouryavi, Mehdi; Farhad Masoudi, S; Rahmani, Faezeh

2015-05-01

Recent studies have shown that D-T neutron generator can be used as a proper neutron source for Boron Neutron Capture Therapy (BNCT) of deep-seated brain tumors. In this paper, radiation shielding calculations have been conducted based on the computational method for designing a BNCT treatment room for a recent proposed D-T neutron source. By using the MCNP-4C code, the geometry of the treatment room has been designed and optimized in such a way that the equivalent dose rate out of the treatment room to be less than 0.5μSv/h for uncontrolled areas. The treatment room contains walls, monitoring window, maze and entrance door. According to the radiation protection viewpoint, dose rate results of out of the proposed room showed that using D-T neutron source for BNCT is safe. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design of a treatment room for an 18 MV Linac

Energy Technology Data Exchange (ETDEWEB)

Hernandez A, L.; Contreras S, H.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Perez L, L. H., E-mail: dameluis@hotmail.co [Instituto Zacatecano del Tumor, Apdo. Postal 294, 98000 Zacatecas (Mexico)

2010-10-15

In this work it has been calculated the treatment room for an 18 MV Linac. The walls thickness, the door and the maze were designed according to the NCRP Report 151 recommendations. The results of this work are contrasted with the Monte Carlo calculations performed with the MCNP5 code where dose equivalent due to neutrons and neutron spectra are estimated at different points inside and outside of the radiotherapy room, verify the shielding thickness obtained are enough to reduce the dose level allowed by the Mexican regulation. (Author)

Observational infant exploratory [14C]-paracetamol pharmacokinetic microdose/therapeutic dose study with accelerator mass spectrometry bioanalysis

Science.gov (United States)

Garner, Colin R; Park, Kevin B; French, Neil S; Earnshaw, Caroline; Schipani, Alessandro; Selby, Andrew M; Byrne, Lindsay; Siner, Sarah; Crawley, Francis P; Vaes, Wouter H J; van Duijn, Esther; deLigt, Rianne; Varendi, Heili; Lass, Jane; Grynkiewicz, Grzegorz; Maruszak, Wioletta; Turner, Mark A

2015-01-01

Aims The aims of the study were to compare [14C]-paracetamol ([14C]-PARA) paediatric pharmacokinetics (PK) after administration mixed in a therapeutic dose or an isolated microdose and to develop further and validate accelerator mass spectrometry (AMS) bioanalysis in the 0–2 year old age group. Methods [14C]-PARA concentrations in 10–15 µl plasma samples were measured after enteral or i.v. administration of a single [14C]-PARA microdose or mixed in with therapeutic dose in infants receiving PARA as part of their therapeutic regimen. Results Thirty-four infants were included in the PARA PK analysis for this study: oral microdose (n = 4), i.v. microdose (n = 6), oral therapeutic (n = 6) and i.v. therapeutic (n = 18). The respective mean clearance (CL) values (SDs in parentheses) for these dosed groups were 1.46 (1.00) l h–1, 1.76 (1.07) l h–1, 2.93 (2.08) l h–1 and 2.72 (3.10) l h–1, t1/2 values 2.65 h, 2.55 h, 8.36 h and 7.16 h and dose normalized AUC(0-t) (mg l–1 h) values were 0.90 (0.43), 0.84 (0.57), 0.7 (0.79) and 0.54 (0.26). Conclusions All necessary ethical, scientific, clinical and regulatory procedures were put in place to conduct PK studies using enteral and systemic microdosing in two European centres. The pharmacokinetics of a therapeutic dose (mg kg–1) and a microdose (ng kg–1) in babies between 35 to 127 weeks post-menstrual age. [14C]-PARA pharmacokinetic parameters were within a two-fold range after a therapeutic dose or a microdose. Exploratory studies using doses significantly less than therapeutic doses may offer ethical and safety advantages with increased bionalytical sensitivity in selected exploratory paediatric pharmacokinetic studies. PMID:25619398

Observational infant exploratory [(14)C]-paracetamol pharmacokinetic microdose/therapeutic dose study with accelerator mass spectrometry bioanalysis.

Science.gov (United States)

Garner, Colin R; Park, Kevin B; French, Neil S; Earnshaw, Caroline; Schipani, Alessandro; Selby, Andrew M; Byrne, Lindsay; Siner, Sarah; Crawley, Francis P; Vaes, Wouter H J; van Duijn, Esther; deLigt, Rianne; Varendi, Heili; Lass, Jane; Grynkiewicz, Grzegorz; Maruszak, Wioletta; Turner, Mark A

2015-07-01

The aims of the study were to compare [(14)C]-paracetamol ([(14)C]-PARA) paediatric pharmacokinetics (PK) after administration mixed in a therapeutic dose or an isolated microdose and to develop further and validate accelerator mass spectrometry (AMS) bioanalysis in the 0-2 year old age group. [(14)C]-PARA concentrations in 10-15 µl plasma samples were measured after enteral or i.v. administration of a single [(14)C]-PARA microdose or mixed in with therapeutic dose in infants receiving PARA as part of their therapeutic regimen. Thirty-four infants were included in the PARA PK analysis for this study: oral microdose (n = 4), i.v. microdose (n = 6), oral therapeutic (n = 6) and i.v. therapeutic (n = 18). The respective mean clearance (CL) values (SDs in parentheses) for these dosed groups were 1.46 (1.00) l h(-1), 1.76 (1.07) l h(-1), 2.93 (2.08) l h(-1) and 2.72 (3.10) l h(-1), t(1/2) values 2.65 h, 2.55 h, 8.36 h and 7.16 h and dose normalized AUC(0-t) (mg l(-1) h) values were 0.90 (0.43), 0.84 (0.57), 0.7 (0.79) and 0.54 (0.26). All necessary ethical, scientific, clinical and regulatory procedures were put in place to conduct PK studies using enteral and systemic microdosing in two European centres. The pharmacokinetics of a therapeutic dose (mg kg(-1)) and a microdose (ng kg(-1)) in babies between 35 to 127 weeks post-menstrual age. [(14)C]-PARA pharmacokinetic parameters were within a two-fold range after a therapeutic dose or a microdose. Exploratory studies using doses significantly less than therapeutic doses may offer ethical and safety advantages with increased bionalytical sensitivity in selected exploratory paediatric pharmacokinetic studies. © 2015 The British Pharmacological Society.

Evaluation on the habitability of a reactor control room for a 1300 MWe PWR following a LOCA

International Nuclear Information System (INIS)

Chang, Si Young; Ha, Chung Woo

1988-01-01

An evaluation on the habitability of a reactor control room for a French 1300 MWe P'4 type PWR following a LOCA has been performed through exposure dose assessment for a reactor operator. A computer code COREX calculating the time-integrated exposure dose has been developed to provide a reasonable basis in this evaluation. Using COREX the exposure dose reduction factors in the reactor control room, the time--integrated radioactivities released into the atmosphere and the time-integrated exposure dose up to 30 days following the LOCA can be also calculated. From the exposure dose assessment, the time-integrated exposure dose to whole body and thyroid of a reactor operator were 0.36 mSv(0.036 rem) and 480 mSv(48.0 rem), respectively after 30 days following the LOCA. The thyroid dose of 480 mSv was nearly 10 times greater than the dose equivalent limit of 50 mSv(5.0 rem) set by the ICRP. Regarding the habitability of a reactor control room, this exceeding thyroid exposure dose could be reduced to 1.2 mSv(0.12 rem), which is 400 times less than the original, by considering the practical 4 work-shifts a day, and by improving the iodine removal efficiency of the filtration system n the reactor control room through the reinforcement of charcoal bed filters for iodine removal. The radiological habitability of a reactor control room, therefore, could be assured by comparing with the dose equivalent limit of the ICRP

Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

Science.gov (United States)

Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

1989-01-01

The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

Calcification of human vascular smooth muscle cells: associations with osteoprotegerin expression and acceleration by high-dose insulin

DEFF Research Database (Denmark)

Olesen, Ping; Knudsen, Kirsten Quyen Nguyen; Wogensen, Lise

2007-01-01

Arterial medial calcifications occur often in diabetic individuals as part of the diabetic macroangiopathy. The pathogenesis is unknown, but the presence of calcifications predicts risk of cardiovascular events. We examined the effects of insulin on calcifying smooth muscle cells in vitro...... and measured the expression of the bone-related molecule osteoprotegerin (OPG). Human vascular smooth muscle cells (VSMCs) were grown from aorta from kidney donors. Induction of calcification was performed with beta-glycerophosphate. The influence of insulin (200 microU/ml or 1,000 microU/ml) on calcification...... calcification in human smooth muscle cells from a series of donors after variable time in culture. Decreased OPG amounts were observed from the cells during the accelerated calcification phase. High dose of insulin (1,000 microU/ml) accelerated the calcification, whereas lower concentrations (200 microU/ml) did...

Dose rate of restroon in facilities using radioisotope

Energy Technology Data Exchange (ETDEWEB)

Cho, Yong Gwi [Dept. of uclear Medicine, Inha University hospital, Incheon (Korea, Republic of); An, Seong Min [Dept. of Radiology, Gachon University, Incheon (Korea, Republic of)

2016-06-15

This study is therefore aimed at measuring the surface dose rate and the spatial dose rate in and outside the radionuclide facility in order to ensure safety of the patients, radiation workers and family care-givers in their use of such equipment and to provide a basic framework for further research on radiation protection. The study was conducted at 4 restrooms in and outside the radionuclide facility of a general hospital in Incheon between May 1 and July 31, 2014. During the study period, the spatial contamination dose rate and the surface contamination dose rate before and after radiation use were measured at the 4 places−thyroid therapy room, PET center, gamma camera room, and outpatient department. According to the restroom use survey by hospitals, restrooms in the radionuclide facility were used not only by patients but also by family care-givers and some of radiation workers. The highest cumulative spatial radiation dose rate was 8.86 mSv/hr at camera room restroom, followed by 7.31 mSv/hr at radioactive iodine therapy room restroom, 2.29 mSv/hr at PET center restroom, and 0.26 mSv/hr at outpatient department restroom, respectively. The surface radiation dose rate measured before and after radiation use was the highest at toilets, which are in direct contact with patient's excretion, followed by the center and the entrance of restrooms. Unsealed radioactive sources used in nuclear medicine are relatively safe due to short half lives and low energy. A patient who received those radioactive sources, however, may become a mobile radioactive source and contaminate areas the patient contacts−camera room, sedation room, and restroom−through secretion and excretion. Therefore, patients administered radionuclides should be advised to drink sufficient amounts of water to efficiently minimize radiation exposure to others by reducing the biological half-life, and members of the public−family care-givers, pregnant women, and children−be as far away from

Spectra and neutron dose of an 18 MV Linac using two geometric models of the head

International Nuclear Information System (INIS)

Barrera, M. T.; Pino, F.; Barros, H.; Sajo-Bohus, L.; Davila, J.; Salcedo, E.; Vega C, H. R.; Benites R, J. L.

2015-10-01

Full text: Using the Monte Carlo method, by MCNP5 code, simulations were performed with different source terms and 2 geometric models of the head to obtain spectra in energy, flow and doses of photo-neutrons at different positions on the stretcher and in the radiotherapy room. The simplest model was a spherical shell of tungsten; the second was the complete model of a heterogeneous head of an accelerator Varian ix. In both models Tosi function was used as a source term. In addition, for the second model Sheikh-Bagheri distribution was used for photons and photo-neutrons were generated. Also in both models the radiotherapy room of Gurve group of the Teaching Medical Center La Trinidad was included, which is equipped with an accelerator Varian Clinic 2100. In this Center passive detectors PADC (Cr-39) were irradiated with neutron converters, with 18 MeV photons radiation. The measured neutron flow was compared with that obtained with Monte Carlo calculations. The Monte Carlo flows are similar to those measured at the isocenter. The simplest model underestimates the neutron flow compared with the calculated flows with the heterogeneous model of the head. (Author)

Resonant coupling applied to superconducting accelerator structures

International Nuclear Information System (INIS)

Potter, James M.; Krawczyk, Frank L.

2013-01-01

The concept of resonant coupling and the benefits that accrue from its application is well known in the world of room temperature coupled cavity linacs. Design studies show that it can be applied successfully between sections of conventional elliptical superconducting coupled cavity accelerator structures and internally to structures with spoked cavity resonators. The coupling mechanisms can be designed without creating problems with high field regions or multipactoring. The application of resonant coupling to superconducting accelerators eliminates the need for complex cryogenic mechanical tuners and reduces the time needed to bring a superconducting accelerator into operation.

I'm dreaming of a white clean room...

CERN Multimedia

Katarina Anthony

2014-01-01

New HIE-ISOLDE cryomodules are now under construction in a state-of-the-art clean room facility in SM18.   The HIE-ISOLDE clean rooms in SM18. HIE-ISOLDE is set to be the world's leading nuclear physics site, ultimately accelerating radioactive nuclei to an impressive 10 MeV/u. Helping the facility reach this energy are new superconducting cryomodules, the first quarter-wave cavity module to be assembled at CERN and necessitating a custom clean-room in SM18. At a towering five metres tall, the new clean room houses a custom assembly frame and associated equipment, moving the components of the 6 tonne cryomodules both vertically and horizontally while they are being assembled. "Each cryomodule is made up of some 10,000 parts, which have come from across the continents to be assembled here," says CERN TE engineer Lloyd Williams, who is managing quality assurance for the project. "Each part is checked by the CERN team, catalogued and thoroughly cleaned, befor...

Accelerated Partial Breast Irradiation With Low-Dose-Rate Interstitial Implant Brachytherapy After Wide Local Excision: 12-Year Outcomes From a Prospective Trial

Energy Technology Data Exchange (ETDEWEB)

Hattangadi, Jona A. [Harvard Radiation Oncology Program, Boston, MA (United States); Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); MacDonald, Shannon M.; Mauceri, Thomas; Ancukiewicz, Marek [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Freer, Phoebe [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Lawenda, Brian [21st Century Oncology, Las Vegas, NV (United States); Alm El-Din, Mohamed A. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Department of Clinical Oncology, Tanta University Hospital, Tanta (Egypt); Gadd, Michele A.; Smith, Barbara L. [Department of Surgical Oncology, Massachusetts General Hospital, Boston, MA (United States); Taghian, Alphonse G., E-mail: ataghian@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)

2012-07-01

Purpose: To evaluate the long-term toxicity, cosmesis, and local control of accelerated partial breast irradiation with implant brachytherapy after wide local excision for Stage T1N0 breast cancer (BCa). Materials and Methods: Between 1997 and 2001, 50 patients with Stage T1N0M0 BCa were treated in a Phase I-II protocol using low-dose-rate accelerated partial breast irradiation with implant brachytherapy after wide local excision and lymph node surgery. The total dose was escalated in three groups: 50 Gy (n = 20), 55 Gy (n = 17), and 60 Gy (n = 13). Patient- and physician-assessed breast cosmesis, patient satisfaction, toxicity, mammographic abnormalities, repeat biopsies, and disease status were prospectively evaluated at each visit. Kendall's tau ({tau}{sub {beta}}) and logistic regression analyses were used to correlate outcomes with dose, implant volume, patient age, and systemic therapy. Results: The median follow-up period was 11.2 years (range, 4-14). The patient satisfaction rate was 67%, 67% reported good-excellent cosmesis, and 54% had moderate-severe fibrosis. Higher dose was correlated with worse cosmetic outcome ({tau}{sub {beta}} 0.6, p < .0001), lower patient satisfaction ({tau}{sub {beta}} 0.5, p < .001), and worse fibrosis ({tau}{sub {beta}} 0.4, p = .0024). Of the 50 patients, 35% had fat necrosis and 34% developed telangiectasias {>=}1 cm{sup 2}. Grade 3-4 late skin and subcutaneous toxicities were seen in 4 patients (9%) and 6 patients (13%), respectively, and both correlated with higher dose ({tau}{sub {beta}} 0.3-0.5, p {<=} .01). One patient had Grade 4 skin ulceration and fat necrosis requiring surgery. Mammographic abnormalities were seen in 32% of the patients, and 30% underwent repeat biopsy, of which 73% were benign. Six patients had ipsilateral breast recurrence: five elsewhere in the breast, and one at the implant site. One patient died of metastatic BCa after recurrence. The 12-year actuarial local control, recurrence

Accelerated Partial Breast Irradiation With Low-Dose-Rate Interstitial Implant Brachytherapy After Wide Local Excision: 12-Year Outcomes From a Prospective Trial

International Nuclear Information System (INIS)

Hattangadi, Jona A.; Powell, Simon N.; MacDonald, Shannon M.; Mauceri, Thomas; Ancukiewicz, Marek; Freer, Phoebe; Lawenda, Brian; Alm El-Din, Mohamed A.; Gadd, Michele A.; Smith, Barbara L.; Taghian, Alphonse G.

2012-01-01

Purpose: To evaluate the long-term toxicity, cosmesis, and local control of accelerated partial breast irradiation with implant brachytherapy after wide local excision for Stage T1N0 breast cancer (BCa). Materials and Methods: Between 1997 and 2001, 50 patients with Stage T1N0M0 BCa were treated in a Phase I-II protocol using low-dose-rate accelerated partial breast irradiation with implant brachytherapy after wide local excision and lymph node surgery. The total dose was escalated in three groups: 50 Gy (n = 20), 55 Gy (n = 17), and 60 Gy (n = 13). Patient- and physician-assessed breast cosmesis, patient satisfaction, toxicity, mammographic abnormalities, repeat biopsies, and disease status were prospectively evaluated at each visit. Kendall’s tau (τ β ) and logistic regression analyses were used to correlate outcomes with dose, implant volume, patient age, and systemic therapy. Results: The median follow-up period was 11.2 years (range, 4–14). The patient satisfaction rate was 67%, 67% reported good-excellent cosmesis, and 54% had moderate-severe fibrosis. Higher dose was correlated with worse cosmetic outcome (τ β 0.6, p β 0.5, p β 0.4, p = .0024). Of the 50 patients, 35% had fat necrosis and 34% developed telangiectasias ≥1 cm 2 . Grade 3–4 late skin and subcutaneous toxicities were seen in 4 patients (9%) and 6 patients (13%), respectively, and both correlated with higher dose (τ β 0.3–0.5, p ≤ .01). One patient had Grade 4 skin ulceration and fat necrosis requiring surgery. Mammographic abnormalities were seen in 32% of the patients, and 30% underwent repeat biopsy, of which 73% were benign. Six patients had ipsilateral breast recurrence: five elsewhere in the breast, and one at the implant site. One patient died of metastatic BCa after recurrence. The 12-year actuarial local control, recurrence-free survival, and overall survival rate was 85% (95% confidence interval, 70–97%), 72% (95% confidence interval, 54–86%), and 87% (95

Dosimetry for electron beam from Microtron accelerator using chemical dosimeters

International Nuclear Information System (INIS)

Joseph, Praveen; Nairy, Rajesha; Sanjeev, Ganesh; Narayana, Y.

2014-01-01

The Microtron is a simple, compact, low cost electron accelerator with excellent beam quality and it can accelerate electrons to relativistic energies. The variable energy Microtron at Mangalore University is used for R and D programmes in basic and applied areas of physics, chemistry, materials science, biological sciences, medical science and industry. While studying the effects of radiation, it is essential to have complete knowledge of absorbed dose. In the present study the absorbed dose and the uniformity of dose distribution at various points due to 8 MeV electron beam from Microtron accelerator has been calculated using different chemical dosimeters. From the dosimetry studies for Microtron accelerator, it is observed that the absorbed doses measured at various dose ranges from 2 Gy to 25 kGy using FBX dosimeters at very low doses, Fricke at intermediate doses and alanine and glutamine at higher doses, varied linearly with increasing electron counts. From the dosimetry studies it is observed that there is a linear relation between dose and electron numbers over a wide range of absorbed doses. It is evaluated that the electron counts of about 1.15 x 10 14 corresponds to an absorbed dose of 100 Gy. Fricke dosimetry was carried out to measure the uniformity in dose distribution at a distance of 30 cm from the beam exit window of the accelerator to ensure the availability of uniform irradiation field size. It is observed that a field size of about 4 x 4 cm is available at 30 cm distance from the beam exit window over which the dose distribution is uniform. The sample size during radiological studies using Microtron was restricted to less than 4 x 4 cm dimension at 30 cm distance from the beam exit window to ensure uniform dose distribution to the sample

Monte-Carlo calculation of irradiation dose content beyond shielding of high-energy accelerators

International Nuclear Information System (INIS)

Mokhov, N.V.; Frolov, V.V.

1975-01-01

The MARS programme, designed for calculating the three-dimensional internuclear cascade in defence of the accelerators by the Monte Carlo method, is described. The methods used to reduce the dispersion and the system of semi-empirical formulas made it possible to exceed the parameters of the existing programmes. By means of a synthesis of the results, registered by MARS and HAMLET programmes, the dosage fields for homogeneous and heterogeneous defence were evaluated. The results of the calculated absorbed and equivalent dose behind the barrier, irradiated by a proton beam, having the energy of Esub(o)=1/1000 GeV are exposed. The dependence of the high- and low-energy neutron, proton, pion, kaon, muonium and γ-quantum dosage on the initial energy and thickness, on the material and the composition of the defence is investigated

Health physics practices at research accelerators

International Nuclear Information System (INIS)

Thomas, R.H.

1976-02-01

A review is given of the uses of particle accelerators in health physics, the text being a short course given at the Health Physics Society Ninth Midyear Topical Symposium in February, 1976. Topics discussed include: (1) the radiation environment of high energy accelerators; (2) dosimetry at research accelerators; (3) shielding; (4) induced activity; (5) environmental impact of high energy accelerators; (6) population dose equivalent calculation; and (7) the application of the ''as low as practicable concept'' at accelerators

Neutron double differential distributions, dose rates and specific activities from accelerator components irradiated by 50-400 MeV protons

International Nuclear Information System (INIS)

Cerutti, F.; Charitonidis, N.; Silari, M.; Charitonidis, N.

2010-01-01

Systematic Monte Carlo simulations with the FLUKA code were performed to estimate the induced radioactivity in five materials commonly used in particle accelerator structures: boron nitride and carbon (dumps and collimators), copper (RF cavities, coils and vacuum chambers), iron and stainless steel (magnets and vacuum chambers). Using a simplified geometry set-up, the five materials were bombarded with protons in the energy range from 50 to 400 MeV. This energy range is typical of intermediate-energy proton accelerators used as injectors to higher-energy machines, as research accelerators for nuclear physics, and in hadron therapy. Ambient dose equivalent rates were calculated at distances up to one meter around the target, for seven cooling times up to six months. A complete inventory of the radionuclides present in the target was calculated for all combinations of target, beam energy and cooling time. The influence of the target size and of self-absorption was investigated. The energy and angular distributions of neutrons escaping from the target were also scored for all materials and beam energies. The influence on the neutron spectra of the presence of concrete walls (the accelerator tunnel) around the target was also estimated. The results of the present study provide a simple database to be used for a first, approximate estimate of the radiological risk to be expected when intervening on activated accelerator components. (authors)

Occupational dosimetry in real time hemodynamic rooms. utility of the system Dose-aware as a training tool; Dosimetria ocupacional en tiempo real en salas de hemodinamica. Utilidad del Sistema Dose-Aware como herramienta formativa

Energy Technology Data Exchange (ETDEWEB)

Pinto Monedero, M.; Rodriguez Cobo, C.; Pifarre Martinez, X.; Ruiz Martin, J.; Barros Candelero, J. M.; Goicolea Ruigomez, J.; Diaz Blaires, G.; Garcia Lunar

2014-02-01

This paper presents the results from a study in a real time dosimetry system used in the catheter laboratory room of our center. The objective was to know the occupational doses per procedure, on the one hand, and, on the other hand, to evaluate its utility as a learning tool for radiation protection purposes with the simultaneous video recording of the interventions. 83 diagnostic and therapeutic procedures were analyzed, and an average dose per procedure of 0,37 {mu}Sv and 0,10 {mu}Sv for the main cardiologist and nurse were obtained, respectively. 36 of these interventions were also recorded and the images were synchronized with the dosimetric information stored and the dosimetry system. The findings were presented to the interventional cardiology team in a learning session. They showed a high level of satisfaction with this new method of optimizing the occupational doses through a customized learning session. (Author)

Accelerator technical design report for high-intensity proton accelerator facility project, J-PARC

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-03-01

This report presents the detail of the technical design of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. The accelerator complex comprises a 400-MeV room-temperature linac (600-MeV superconducting linac), 3-GeV rapid-cycling synchrotron (RCS), and a 50-GeV synchrotron (MR). The 400-MeV beam is injected to the RCS, being accelerated to 3 GEV. The 1-MW beam thus produced is guided to the Materials Life Science Experimental Facility, with both the pulsed spallation neutron source and muon source. A part of the beam is transported to the MR, which provides the 0.75-MW beam to either the Nuclear and Fundamental Particle Experimental Facility or the Neutrino Production Target. On the other hand, the beam accelerated to 600 MeV by the superconducting linac is used for the Nuclear Waster Transmutation Experiment. In this way, this facility is unique, being multipurpose one, including many new inventions and Research and Development Results. This report is based upon the accomplishments made by the Accelerator Group and others of the Project Team, which is organized on the basis of the Agreement between JAERI and KEK on the Construction and Research and Development of the High-Intensity Proton Accelerator Facility. (author)

SU-F-J-203: Retrospective Assessment of Delivered Proton Dose in Prostate Cancer Patients Based On Daily In-Room CT Imaging

Energy Technology Data Exchange (ETDEWEB)

Stuetzer, K; Paessler, T [OncoRay - National Center for Radiation Research in Oncology, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universitaet Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Valentini, C; Thiele, J; Hoelscher, T [Department of Radiation Oncology, University Hospital Carl Gustav Carus, Techenische Universitaet Dresden (Germany); Exner, F [OncoRay - National Center for Radiation Research in Oncology, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universitaet Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); now with: University of Wuerzburg, Department of Radiation Oncology, Wuerzburg (Germany); Krause, M; Richter, C [OncoRay - National Center for Radiation Research in Oncology, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universitaet Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Department of Radiation Oncology, University Hospital Carl Gustav Carus, Techenische Universitaet Dresden (Germany); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology, Dresden (Germany); German Cancer Consortium (DKTK), Dresden, Germany and German Cancer Research Center (DKFZ), Heidelberg (Germany)

2016-06-15

Purpose: Retrospective calculation of the delivered proton dose in prostate cancer patients based on a unique dataset of daily CT images. Methods: Inter-fractional motion in prostate cancer patients treated at our proton facility is counteracted by water-filled endorectal ballon and bladder filling protocol. Typical plans (XiO, Elekta Instruments AB, Stockholm) for 74 Gy(RBE) sequential boost treatment in 37 fractions include two series of opposing lateral double-scattered proton beams covering the respective iCTV. Stability of fiducial markers and anatomy were checked in 12 patients by daily scheduled in-room control CT (cCT) after immobilization and positioning according to bony anatomy utilizing orthogonal X-ray. In RayStation 4.6 (RaySearch Laboritories AB, Stockholm), all cCTs are delineated retrospectively and the treatment plans were recalculated on the planning CT and the registered cCTs. All fraction doses were accumulated on the planning CT after deformable registration. Parameters of delivered dose to iCTV (D98%>95%, D2%<107%), bladder (V75Gy<15%, V70Gy<25%, V65Gy<30%), rectum (V70Gy<10%, V50Gy<40%) and femoral heads (V50Gy<5%) are compared to those in the treatment plan. Intra-therapy variation is represented in DVH bands. Results: No alarming differences were observed between planned and retrospectively accumulated dose: iCTV constraints were met, except for one patient (D98%=94.6% in non-boosted iCTV). Considered bladder and femoral head values were below the limits. Rectum V70Gy was slightly exceeded (<11.3%) in two patients. First intra-therapy variability analysis in 4 patients showed no timedependent parameter drift, revealed strongest variability for bladder dose. In some fractions, iCTV coverage (D98%) and rectum V70Gy was missed. Conclusion: Double scattered proton plans are accurately delivered to prostate cancer patients due to fractionation effects and the applied precise positioning and immobilization protocols. As a result of rare

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

Neutron fluence produced in medical accelerators

International Nuclear Information System (INIS)

Castro, R.C.; Silva, A.X. da; Crispim, V.R.

2004-01-01

Radiotherapy with photon and electron beams still represents the most diffused technique to control and treat tumour diseases. To increase the treatment efficiency, accelerators of higher energy are used, the increase of electron and photon energy is joined with generation of undesired fast neutron that contaminated the therapeutic beam and give a non-negligible contribution to the patient dose. In this work we have simulated with the MCNP4B code the produced neutron spectra in the interaction between the beam and the head to the accelerator and estimating the equivalent dose for neutrons by x-ray dose for aims far from the targets. (author)

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

Room-temperature ferromagnetism observed in C-/N-/O-implanted MgO single crystals

Science.gov (United States)

Li, Qiang; Ye, Bonian; Hao, Yingping; Liu, Jiandang; Zhang, Jie; Zhang, Lijuan; Kong, Wei; Weng, Huimin; Ye, Bangjiao

2013-01-01

MgO single crystals were implanted with 70 keV C/N/O ions at room temperature with respective doses of 2 × 1016 and 2 × 1017 ions/cm2. All samples with high-dose implantation showed room temperature hysteresis in magnetization loops. Magnetization and slow positron annihilation measurements confirmed that room temperature ferromagnetism in O-implanted samples was attributed to the presence of Mg vacancies. Furthermore, the introduction of C or N played more effective role in ferromagnetic performance than Mg vacancies. Moreover, the magnetic moment possibly occurred from the localized wave function of unpaired electrons and the exchange interaction formed a long-range magnetic order.

Accelerator-driven neutron sources for materials research

International Nuclear Information System (INIS)

Jameson, R.A.

1990-01-01

Particle accelerators are important tools for materials research and production. Advances in high-intensity linear accelerator technology make it possible to consider enhanced neutron sources for fusion material studies or as a source of spallation neutrons. Energy variability, uniformity of target dose distribution, target bombardment from multiple directions, time-scheduled dose patterns, and other features can be provided, opening new experimental opportunities. New designs have also been used to ensure hands-on maintenance on the accelerator in these factory-type facilities. Designs suitable for proposals such as the Japanese Energy-Selective Intense Neutron Source, and the international Fusion Materials Irradiation Facility are discussed

Method for measuring and evaluation dose equivalent rate from fast neutrons in mixed gamma-neutron fields around particles accelerators

International Nuclear Information System (INIS)

Cruceru, I.; Sandu, M.; Cruceru, M.

1994-01-01

A method for measuring and evaluation of doses and dose equivalent rate in mixed gamma- neutron fields is discussed in this paper. The method is basedon a double detector system consist of an ionization chamber with components made from a plastic scintillator, coupled to on photomultiplier. Generally the radiation fields around accelerators are complex, often consisting of many different ionizing radiations extending over a broad range of energies. This method solve two major difficulties: determination of response functions of radiation detectors; interpretation of measurement and determination of accuracy. The discrimination gamma-fast neutrons is assured directly without a pulse shape discrimination circuit. The method is applied to mixed fields in which particle energies are situated in the energy range under 20 MeV and an izotropic emision (Φ=10 4 -10 11 n.s -1 ). The dose equivalent rates explored is 0.01mSV--0.1SV

Accelerating Improvements in the Energy Efficiency of Room Air Conditioners (RACs) in India: Potential, Cost-Benefit, and Policies (Interim Assessment)

Energy Technology Data Exchange (ETDEWEB)

Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-06-01

Falling AC prices, increasing incomes, increasing urbanization, and high cooling requirements due to hot climate are all driving increasing uptake of Room Air Conditioners (RACs) in the Indian market. Air conditioning already comprises 40-60% of summer peak load in large metropolitan Indian cities such as Delhi and is likely to contribute 150 GW to the peak demand in 2030. Standards and labeling policies have contributed to improving the efficiency of RACs in India by about 2.5% in the last 10 years (2.5% per year) while inflation adjusted RAC prices have continued to decline. In this paper, we assess the technical feasibility, cost-benefit, and required policy enhancements by further accelerating the efficiency improvement of RACs in India. We find that there are examples of significantly more accelerated improvements such as those in Japan and Korea where AC efficiency improved by more than 7% per year resulting in almost a doubling of energy efficiency in 7 to 10 years while inflation adjusted AC prices continued to decline. We find that the most efficient RAC sold on the Indian market is almost twice as efficient as the typical AC sold on the market and hence see no technology constraints in a similar acceleration of improvement of efficiency. If starting 2018, AC efficiency improves at a rate of 6% instead of 3%, 40-60 GW of peak load (equivalent to connected load of 5-6 billion LED bulbs), and over 75 TWh/yr (equivalent to 60 million consumers consuming 100 kWh/month) will be saved by 2030; total peak load reduction would be as high as 50 GW. The net present value (NPV) of the consumer benefit between 2018-2030 will range from Rs 18,000 Cr in the most conservative case (in which prices don’t continue to decline and increase based estimates of today’s cost of efficiency improvement) to 140,000 Cr in a more realistic case (in which prices are not affected by accelerated efficiency improvement as shown by historical experience). This benefit is achievable by

Accelerated partial-breast irradiation with interstitial implants. The clinical relevance of the calculation of skin doses

International Nuclear Information System (INIS)

Ott, O.J.; Lotter, M.; Sauer, R.; Strnad, V.

2007-01-01

Purpose: To describe relative skin dose estimations and their impact on cosmetic outcome in interstitial multicatheter accelerated partial-breast irradiation (APBI). Patients and Methods: Between April 2001 and January 2005, 105 consecutive patients with early breast cancer were recruited in Erlangen, Germany, for this substudy of the German-Austrian APBI phase II trial. 51% (54/105) received pulsed-dose-rate (PDR), and 49% (51/105) high-dose-rate (HDR) brachytherapy. Prescribed reference dose for HDR brachytherapy was 32 Gy in eight fractions of 4 Gy, twice daily. Prescribed reference dose in PDR brachytherapy was 49.8 Gy in 83 consecutive fractions of 0.6 Gy every hour. Total treatment time was 3-4 days. With a wire cross on the skin surface during the brachytherapy-planning procedure the minimal, mean and maximal relative skin doses (SD min% , SD max% , SD mean% ) were recorded. Endpoint of this evaluation was the cosmetic outcome in relation to the relative skin doses. Results: Median follow-up time was 38 months (range, 19-65 months). Cosmetic results for all patients were excellent in 57% (60/105), good in 36% (38/105), and fair in 7% (7/105). The SD min% (27.0% vs. 31.7%; p = 0.032), SD mean% (34.2% vs. 38.1%; p 0.008), and SD max% (38.2% vs. 46.4%; p 0.003) were significantly lower for patients with excellent cosmetic outcome compared to patients with a suboptimal outcome. SD mean% (37.6% vs. 34.2%; p = 0.026) and SD max% (45.4% vs. 38.2%; p = 0.008) were significantly higher for patients with good cosmetic outcome compared with the patients with excellent results. Conclusion: The appraisal of skin doses has been shown to be relevant to the achievement of excellent cosmetic outcome. Further investigations are necessary, especially on the basis of CT-based brachytherapy planning, to further improve the treatment results of multicatheter APBI. (orig.)

An improved Monte Carlo (MC) dose simulation for charged particle cancer therapy

Energy Technology Data Exchange (ETDEWEB)

Ying, C. K. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang, Malaysia and School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu (Malaysia); Kamil, W. A. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang, Malaysia and Radiology Department, Hospital USM, Kota Bharu (Malaysia); Shuaib, I. L. [Advanced Medical and Dental Institute, AMDI, Universiti Sains Malaysia, Penang (Malaysia); Matsufuji, Naruhiro [Research Centre of Charged Particle Therapy, National Institute of Radiological Sciences, NIRS, Chiba (Japan)

2014-02-12

Heavy-particle therapy such as carbon ion therapy are more popular nowadays because of the nature characteristics of charged particle and almost no side effect to patients. An effective treatment is achieved with high precision of dose calculation, in this research work, Geant4 based Monte Carlo simulation method has been used to calculate the radiation transport and dose distribution. The simulation have the same setting with the treatment room in Heavy Ion Medical Accelerator, HIMAC. The carbon ion beam at the isocentric gantry nozzle for the therapeutic energy of 290 MeV/u was simulated, experimental work was carried out in National Institute of Radiological Sciences, NIRS, Chiba, Japan by using the HIMAC to confirm the accuracy and qualities dose distribution by MC methods. The Geant4 based simulated dose distribution were verified with measurements for Bragg peak and spread out Bragg peak (SOBP) respectively. The verification of results shows that the Bragg peak depth-dose and SOBP distributions in simulation has good agreement with measurements. In overall, the study showed that Geant4 based can be fully applied in the heavy-ion therapy field for simulation, further works need to be carry on to refine and improve the Geant4 MC simulations.

An improved Monte Carlo (MC) dose simulation for charged particle cancer therapy

International Nuclear Information System (INIS)

Ying, C. K.; Kamil, W. A.; Shuaib, I. L.; Matsufuji, Naruhiro

2014-01-01

Heavy-particle therapy such as carbon ion therapy are more popular nowadays because of the nature characteristics of charged particle and almost no side effect to patients. An effective treatment is achieved with high precision of dose calculation, in this research work, Geant4 based Monte Carlo simulation method has been used to calculate the radiation transport and dose distribution. The simulation have the same setting with the treatment room in Heavy Ion Medical Accelerator, HIMAC. The carbon ion beam at the isocentric gantry nozzle for the therapeutic energy of 290 MeV/u was simulated, experimental work was carried out in National Institute of Radiological Sciences, NIRS, Chiba, Japan by using the HIMAC to confirm the accuracy and qualities dose distribution by MC methods. The Geant4 based simulated dose distribution were verified with measurements for Bragg peak and spread out Bragg peak (SOBP) respectively. The verification of results shows that the Bragg peak depth-dose and SOBP distributions in simulation has good agreement with measurements. In overall, the study showed that Geant4 based can be fully applied in the heavy-ion therapy field for simulation, further works need to be carry on to refine and improve the Geant4 MC simulations

An improved Monte Carlo (MC) dose simulation for charged particle cancer therapy

International Nuclear Information System (INIS)

Ying, C.K.; Kamil, W.A.; Shuaib, I.L.; Ying, C.K.; Kamil, W.A.

2013-01-01

Full-text: Heavy-particle therapy such as carbon ion therapy are more popular nowadays because of the nature characteristics of charged particle and almost no side effect to patients. An effective treatment is achieved with high precision of dose calculation, in this research work, Geant4 based Monte Carlo simulation method has been used to calculate the radiation transport and dose distribution. The simulation have the same setting with the treatment room in Heavy Ion Medical Accelerator, HIMAC. The carbon ion beam at the isocentric gantry nozzle for the therapeutic energy of 290 MeV/u was simulated, experimental work was carried out in National Institute of Radiological Sciences, NIRS, Chiba, Japan by using the HIMAC to confirm the accuracy and qualities dose distribution by MC methods. The Geant4 based simulated dose distribution were verified with measurements for Bragg peak and spread out Bragg peak (SOBP) respectively. The verification of results shows that the Bragg peak depth-dose and SOBP distributions in simulation has good agreement with measurements. In overall, the study showed that Geant4 based can be fully applied in the heavy ion therapy field for simulation, further works need to be carry on to refine and improve the Geant4 MC simulations. (author)

Image-Guided Stereotactic Radiosurgery Using a Specially Designed High-Dose-Rate Linac

International Nuclear Information System (INIS)

Bayouth, John E.; Kaiser, Heather S.; Smith, Mark C.; Pennington, Edward C.; Anderson, Kathleen M. C.; Ryken, Timothy C.; Buatti, John M.

2007-01-01

Stereotactic radiosurgery and image-guided radiotherapy (IGRT) place enhanced demands on treatment delivery machines. In this study, we describe a high-dose-rate output accelerator as a part of our stereotactic IGRT delivery system. The linac is a Siemens Oncor without a flattening filter, and enables dose rates to reach 1000 monitor units (MUs) per minute. Even at this high-dose-rate, the linac dosimetry system remains robust; constancy, linearity, and beam energy remain within 1% for 3 to 1000 MU. Dose profiles for larger field sizes are not flat, but they are radially symmetric and, as such, able to be modeled by a treatment planning system. Target localization is performed via optical guidance utilizing a 3-dimensional (3D) ultrasound probe coupled to an array of 4 infrared light-emitting diodes. These diodes are identified by a fixed infrared camera system that determines diode position and, by extension, all objects imaged in the room coordinate system. This system provides sub-millimeter localization accuracy for cranial applications and better than 1.5 mm for extracranial applications. Because stereotactic IGRT can require significantly longer times for treatment delivery, the advantages of the high-dose-rate design and its direct impact on IGRT are discussed

222Radon concentration and irradiation dose inside the department of nuclear medicine in Wuhan

International Nuclear Information System (INIS)

Cheng Xiaoli; Wang Changyin; Gao Jianhua; Zou Xiaofeng

2002-01-01

Objective: Inspecting the high radioactivity area in department of nuclear medicine in Wuhan region and estimating the irradiation dose on relevant doctors. Methods: Select six 'three A' hospitals' high radioactivity area in department of nuclear medicine and common residential houses as examples. A half-year surveillance using 222 Rn detector (type LIH-2) was performed. Results: In high radioactivity rooms, imaging rooms residential houses, the average 222 Rn concentration are 27.8, 48.2, 27.1 (Bq·m -3 ) respectively. Effective dose equivalent absorbed by doctors in high radioactivity room and imaging room are 0.16 and 0.28 mSv. The authors estimated that the effective dose equivalent of doctors in these two room and common residents per year are 0.84, 0.70 and 0.64 mSv respectively. Conclusions: Doctors in imaging room and high radioactivity room are exposed to a relatively higher annual effective dose than common residents. But they are still within the normal range. Only two imaging rooms have high 222 Rn concentrations, which will cause potential harm

Is there a future for high energy accelerators?

International Nuclear Information System (INIS)

Tigner, M.

1993-01-01

The question of continuing viability of high energy accelerators as instruments of fundamental physics is discussed. It is seen that the next decade in elementary CM energies beyond SSC may be achievable with accelerators that can be imagined now. Beyond that there is room for doubt that accelerators will be the instrument of choice. History teaches that there is a good likelihood that the present perspective on the matter will be much different when the results from the few TeV region of elementary collision energies are in hand

HABIT, Toxic and Radioactive Release Hazards in Reactor Control Room

International Nuclear Information System (INIS)

Stage, S.A.

2005-01-01

1 - Description of program or function: HABIT is a package of computer codes designed to be used for the evaluation of control room habitability in the event of an accidental release of toxic chemicals or radioactive materials. 2 - Methods: Given information about the design of a nuclear power plant, a scenario for the release of toxic or radionuclides, and information about the air flows and protection systems of the control room, HABIT can be used to estimate the chemical exposure or radiological dose to control room personnel

Evaluation using Monte Carlo simulations, of the effect of a shielding, called external shielding, for fotoneutrons generated in linear accelerators, using the computational model of Varian accelerator 2300 C/D operating in eight rotation angles of the GA

International Nuclear Information System (INIS)

Silva, Hugo R.; Silva, Ademir X.; Rebello, Wilson F.; Silva, Maria G.

2011-01-01

This paper aims to present the results obtained by Monte Carlo simulation of the effect of shielding against neutrons, called External Shielding, to be placed on the heads of linear accelerators used in radiotherapy. For this, it was used the radiation transport code Monte Carlo N-Particle - MCNPX, in which were developed computational model of the head of the linear accelerator Varian 2300 C/D. The equipment was simulated within a bunker, operating at energies of 10, 15 and 18 MV, considering the rotation of the gantry at eight different angles ( 0 deg, 45 deg, 90 deg, 135 deg, 180 deg, 225 deg, 270 deg and 315 deg), in all cases, the equipment was modeled without and with the shielding positioned attached to the head of the accelerator on its bottom. In each of these settings, it was calculated the Ambient Dose Equivalent due to neutron H * (10)n on points situated in the region of the patient (region of interest for evaluation of undesirable neutron doses on the patient) and in the maze of radiotherapy room (region of interest for shielding the access door to the bunker). It was observed for all energies of equipment operation as well as for all angles of inclination of the gantry, a significant reduction in the values of H * (10) n when the equipment operated with the external shielding, both in the region of the patient as in the region of the maze. (author)

Microdroplets Accelerate Ring Opening of Epoxides

Science.gov (United States)

Lai, Yin-Hung; Sathyamoorthi, Shyam; Bain, Ryan M.; Zare, Richard N.

2018-05-01

The nucleophilic opening of an epoxide is a classic organic reaction that has widespread utility in both academic and industrial applications. We have studied the reaction of limonene oxide with morpholine to form 1-methyl-2-morpholino-4-(prop-1-en-2-yl) cyclohexan-1-ol in bulk solution and in electrosprayed microdroplets with a 1:1 v/ v water/methanol solvent system. We find that even after 90 min at room temperature, there is no product detected by nuclear magnetic resonance spectroscopy in bulk solution whereas in room-temperature microdroplets (2-3 μm in diameter), the yield is already 0.5% in a flight time of 1 ms as observed by mass spectrometry. This constitutes a rate acceleration of 105 in the microdroplet environment, if we assume that as much as 5% of product is formed in bulk after 90 min of reaction time. We examine how the reaction rate depends on droplet size, solvent composition, sheath gas pressure, and applied voltage. These factors profoundly influence the extent of reaction. This dramatic acceleration is not limited to just one system. We have also found that the nucleophilic opening of cis-stilbene oxide by morpholine is similarly accelerated. Such large acceleration factors in reaction rates suggest the use of microdroplets for ring opening of epoxides in other systems, which may have practical significance if such a procedure could be scaled. [Figure not available: see fulltext.

Microdroplets Accelerate Ring Opening of Epoxides

Science.gov (United States)

Lai, Yin-Hung; Sathyamoorthi, Shyam; Bain, Ryan M.; Zare, Richard N.

2018-03-01

The nucleophilic opening of an epoxide is a classic organic reaction that has widespread utility in both academic and industrial applications. We have studied the reaction of limonene oxide with morpholine to form 1-methyl-2-morpholino-4-(prop-1-en-2-yl) cyclohexan-1-ol in bulk solution and in electrosprayed microdroplets with a 1:1 v/v water/methanol solvent system. We find that even after 90 min at room temperature, there is no product detected by nuclear magnetic resonance spectroscopy in bulk solution whereas in room-temperature microdroplets (2-3 μm in diameter), the yield is already 0.5% in a flight time of 1 ms as observed by mass spectrometry. This constitutes a rate acceleration of 105 in the microdroplet environment, if we assume that as much as 5% of product is formed in bulk after 90 min of reaction time. We examine how the reaction rate depends on droplet size, solvent composition, sheath gas pressure, and applied voltage. These factors profoundly influence the extent of reaction. This dramatic acceleration is not limited to just one system. We have also found that the nucleophilic opening of cis-stilbene oxide by morpholine is similarly accelerated. Such large acceleration factors in reaction rates suggest the use of microdroplets for ring opening of epoxides in other systems, which may have practical significance if such a procedure could be scaled. [Figure not available: see fulltext.

Studies on the radicidation of natural food colorants. Effects of electron energy (accelerating voltages) and dose rate of ionizing radiation on functional properties of beet red colorant

International Nuclear Information System (INIS)

Higashimura, Yutaka; Tada, Mikiro; Furuta, Masakazu

2003-01-01

In order to the practical use of radicidation of beet red, natural food colorant with low heat stability and high possibility of microbe contamination, we studied on the energy dependency and dose rate effect for the influence on functional properties of the beet red colorant. For the elucidation of energy dependency, the γ-ray (1.33 MeV) and electron beams with different accelerating voltages (0.75, 1, 2.5, 5 and 10 MeV) were used. The dose rate effect was studied under the different dose rate by using γ-ray (0.723, 1.91 and 4.55 kGy/h) and electron beams with accelerating voltage of 10 MeV (1.0 x 10 3 , 2.6 x 10 3 , 7.0 x 10 3 , 7.0 x 10 3 , 2.0 x 10 4 and 5.0 x 10 4 kGy/h). The results obtained in this study showed that regardless of these energy and dose rate, the functional properties of the beet red colorant were little affected by irradiation less than 25 kGy of ionizing radiations. (author)

The destruction of parasitic resistant stages in sewage sludge by irradiation with low accelerating voltage electrons

International Nuclear Information System (INIS)

Enigk, K.; Holl, P.; Dey-Hazra, A.; Polymer-Physik G.m.b.H. und Co. K.G., Tuebingen

1975-01-01

The destroying effect of ionizing radiation on parasitic resistant stages in sludge has been tested. Suitable for that process is an electron beam accelerator which will be provided with energy from the electric power supply network which can be switched on and off according to the requirements. Such modern utilities have an enormous beam capacity and a high operating safety. The process is working according to the continuous flow principle and at room temperature. In a series of 13 experiments the effect of different doses has been tested. A dose of 480 kRad (accelerating voltage: 400 kV, beam current: 10 mA , irradiation time: 24 sec.) can easily obtained in practical work and is economically acceptable. By these means approximately 97% of the following parasitic stages have been destroyed: undeveloped eggs of Ascaris suum, Trichuris suis, Fasciola hepatica and gastrointestinal strongylids of pigs, embryonated eggs of Capillaria obsignata and probably of Taenia spec. A few third-stage larvae of Oesophagostomum (Strongylidae) of pigs survived even 108 sec of irradiation; however, they did not develop to maturity in the definitive host. Approximately 25% of the sporulated oocysts of Eimeria tenella were still infective after 108 sec of irradiation. (orig.) [de

Accelerator shield design of KIPT neutron source facility

International Nuclear Information System (INIS)

Zhong, Z.; Gohar, Y.

2013-01-01

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generated by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total

Industrial applications of electron accelerators

International Nuclear Information System (INIS)

Singh, A.

1994-01-01

The interaction of high-energy radiation with organic systems produces very reactive, short-lived, ionic and free-radical species. The chemical changes brought about by these species are very useful in several systems, and are the basis of the growth of the electron processing industry. Some typical areas of the industrial use of electron accelerators are crosslinking wire and cable insulation, manufacturing heat shrink plastic items, curing coatings, and partially curing rubber products. Electron accelerators are also being considered in other areas such as sewage treatment, sterilizing medical disposables, and food irradiation. An emerging application of industrial electron accelerators is the production of advanced composites for the aerospace and other industries. Traditionally, the carbon-, aramid- and glass-fibre-reinforced composites with epoxy matrices are produced by thermal curing. However, equivalent composites with acrylated-epoxy matrices can be made by electron curing. Cost estimates suggest that electron curing could be more economical than thermal curing. Food irradiation has traditionally been an application for 60 Co γ-radiation. With the increasing demand for food irradiation in various countries, it may become necessary to use electron accelerators for this purpose. Since the dose rate during gamma and electron irradiation are generally very different, a review of the relevant work on the effect of dose rates has been done. This paper presents an overview of the industrial applications of electron accelerator for radiation processing, emphasises the electron curing of advanced composites and, briefly reviews the dose-rate effects in radiation processing of advanced composites and food irradiation. (author). 84 refs., 8 tabs

Dependence of total dose response of bipolar linear microcircuits on applied dose rate

International Nuclear Information System (INIS)

McClure, S.; Will, W.; Perry, G.; Pease, R.L.

1994-01-01

The effect of dose rate on the total dose radiation hardness of three commercial bipolar linear microcircuits is investigated. Total dose tests of linear bipolar microcircuits show larger degradation at 0.167 rad/s than at 90 rad/s even after the high dose rate test is followed by a room temperature plus a 100 C anneal. No systematic correlation could be found for degradation at low dose rate versus high dose rate and anneal. Comparison of the low dose rate with the high dose rate anneal data indicates that MIL-STD-883, method 1019.4 is not a worst-case test method when applied to bipolar microcircuits for low dose rate space applications

ORNL 25 MV tandem accelerator control system

International Nuclear Information System (INIS)

Juras, R.C.; Biggerstaff, J.A.; Hoglund, D.E.

1985-01-01

The CAMAC-based control system for the 25 MV tandem electrostatic accelerator of the Holifield Heavy Ion Research Facility at Oak Ridge National Laboratory (ORNL) was specified by ORNL and built by the National Electrostatics Corporation. Two Perkin-Elmer 32-bit minicomputers are used in the system, a message switching computer and a supervisory computer. The message switching computer transmits and receives control information on six serial highways. This computer shares memory with the supervisory computer. Operator consoles are located on a serial highway; control is by means of a console CRT, trackball, and assignable shaft encoders and meters. Two identical consoles operate simultaneously: one is located in the tandem control room; the other is located in the cyclotron control room to facilitate operation during injection of tandem beams into the cyclotron or when beam lines under control of the cyclotron control system are used. The supervisory computer is used for accelerator parameter setup calculations, actual accelerator setup for new beams based on scaled, recorded parameters from previously run beams, and various other functions. Nearly seven years of control system operation and improvements will be discussed

Experimental Platform for Ultra-high Dose Rate FLASH Irradiation of Small Animals Using a Clinical Linear Accelerator

Energy Technology Data Exchange (ETDEWEB)

Schüler, Emil; Trovati, Stefania; King, Gregory; Lartey, Frederick; Rafat, Marjan; Villegas, Manuel; Praxel, A. Joe [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Loo, Billy W., E-mail: BWLoo@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Maxim, Peter G., E-mail: PMaxim@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States)

2017-01-01

Purpose: A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, “FLASH”) potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC). Methods and Materials: We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head. Results: Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume. Conclusions: We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community.

Experimental Platform for Ultra-high Dose Rate FLASH Irradiation of Small Animals Using a Clinical Linear Accelerator.

Science.gov (United States)

Schüler, Emil; Trovati, Stefania; King, Gregory; Lartey, Frederick; Rafat, Marjan; Villegas, Manuel; Praxel, A Joe; Loo, Billy W; Maxim, Peter G

2017-01-01

A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologic approach for FLASH electron small animal irradiation with a clinically available linear accelerator (LINAC). We investigated the FLASH irradiation potential of a Varian Clinac 21EX in both clinical mode and after tuning of the LINAC. We performed detailed FLUKA Monte Carlo and experimental dosimetric characterization at multiple experimental locations within the LINAC head. Average dose rates of ≤74 Gy/s were achieved in clinical mode, and the dose rate after tuning exceeded 900 Gy/s. We obtained 220 Gy/s at 1-cm depth for a >4-cm field size with 90% homogeneity throughout a 2-cm-thick volume. We present an approach for using a clinical LINAC for FLASH irradiation. We obtained dose rates exceeding 200 Gy/s after simple tuning of the LINAC, with excellent dosimetric properties for small animal experiments. This will allow for increased availability of FLASH irradiation to the general research community. Copyright © 2016 Elsevier Inc. All rights reserved.

Progress toward NLC / GLC prototype accelerator structures

CERN Document Server

Wang, J W; Arkan, T; Baboi, N; Boffo, C; Bowden, G B; Burke, D L; Carter, H; Chan, J; Cornuelle, J; Döbert, Steffen; Dolgashev, Valery A; Finley, D; Gonin, I; Higashi, Y; Higo, T; Jones, R M; Khabiboulline, T; Kume, T; Lewandowski, J; Li, Z; Miller, R H; Mishra, S; Morozumi, Y; Nantista, C; Pearson, C; Romanov, G; Ruth, Ronald D; Solyak, N; Tantawi, S; Toge, N; Ueno, K; Wilson, P B; Xiao, L

2004-01-01

The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and couplers, fundamental mode couplers, optimized accelerator cavities as well as plans for future structures. We emphasize techniques to reduce the field on the surface of the copper structures (in order to achieve high accelerating gradients), limit the dipole wakefields (to relax alignment tolerance and prevent a beam break up instability) and improve shunt impedance (to reduce the RF power required).

The continuous electron beam accelerator facility

International Nuclear Information System (INIS)

Grunder, H.A.

1989-01-01

Tunnel construction and accelerator component development, assembly, and testing are under way at the Continuous Electron Beam Accelerator Facility. CEBAF's 4-GeV, 200-μA superconducting recirculating accelerator will provide cw beam to simultaneous experiments in three end stations for studies of the nuclear many-body system, its quark substructure, and the strong and electroweak interactions governing this form of matter. Prototype accelerating cavities, assembled in cryostats and tested on site, continue to exceed performance specifications. An on-site liquid helium capability supports cryostat development and cavity testing. Major elements of the accelerator instrumentation and control hardware and software are in use in cryogenics, rf, and injector tests. Prototype rf systems have been operated and prototype klystrons have been ordered. The initial, 100-keV, room-temperature region of the 45-MeV injector is operational and meets specifications. CEBAF's end stations have been conceptually designed; experimental equipment conceptual designs will be completed in 1989. 2 refs., 5 figs., 2 tabs

Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

Science.gov (United States)

Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Eng, Tony; Papanikolaou, Nikos

2010-09-01

A low-energy electronic brachytherapy source (EBS), the model S700 Axxent™ x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

Energy Technology Data Exchange (ETDEWEB)

Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos [Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, TX 78229 (United States); Cheng, Chih-Yao, E-mail: shic@uthscsa.ed [Radiation Oncology Department, Oklahoma University Health Science Center, Oklahoma, OK 73104 (United States)

2010-09-21

A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V{sub 100} reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as

Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

International Nuclear Information System (INIS)

Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos; Cheng, Chih-Yao

2010-01-01

A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V 100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

A Phase I Dose-Escalation Study (ISIDE-BT-1) of Accelerated IMRT With Temozolomide in Patients With Glioblastoma

International Nuclear Information System (INIS)

Morganti, Alessio G.; Balducci, Mario; Salvati, Maurizio; Esposito, Vincenzo; Romanelli, Pantaleo; Ferro, Marica; Calista, Franco; Digesu, Cinzia; Macchia, Gabriella; Ianiri, Massimo; Deodato, Francesco; Cilla, Savino; Piermattei, Angelo M.P.; Valentini, Vincenzo; Cellini, Numa; Cantore, Gian Paolo

2010-01-01

Purpose: To determine the maximum tolerated dose (MTD) of fractionated intensity-modulated radiotherapy (IMRT) with temozolomide (TMZ) in patients with glioblastoma. Methods and Materials: A Phase I clinical trial was performed. Eligible patients had surgically resected or biopsy-proven glioblastoma. Patients started TMZ (75 mg/day) during IMRT and continued for 1 year (150-200 mg/day, Days 1-5 every 28 days) or until disease progression. Clinical target volume 1 (CTV1) was the tumor bed ± enhancing lesion with a 10-mm margin; CTV2 was the area of perifocal edema with a 20-mm margin. Planning target volume 1 (PTV1) and PTV2 were defined as the corresponding CTV plus a 5-mm margin. IMRT was delivered in 25 fractions over 5 weeks. Only the dose for PTV1 was escalated (planned dose escalation: 60 Gy, 62.5 Gy, 65 Gy) while maintaining the dose for PTV2 (45 Gy, 1.8 Gy/fraction). Dose limiting toxicities (DLT) were defined as any treatment-related nonhematological adverse effects rated as Grade ≥3 or any hematological toxicity rated as ≥4 by Radiation Therapy Oncology Group (RTOG) criteria. Results: Nineteen consecutive glioblastoma were treated with step-and-shoot IMRT, planned with the inverse approach (dose to the PTV1: 7 patients, 60 Gy; 6 patients, 62.5 Gy; 6 patients, 65 Gy). Five coplanar beams were used to cover at least 95% of the target volume with the 95% isodose line. Median follow-up time was 23 months (range, 8-40 months). No patient experienced DLT. Grade 1-2 treatment-related neurologic and skin toxicity were common (11 and 19 patients, respectively). No Grade >2 late neurologic toxicities were noted. Conclusion: Accelerated IMRT to a dose of 65 Gy in 25 fractions is well tolerated with TMZ at a daily dose of 75 mg.

A study on leakage radiation dose at ELV-4 electron accelerator bunker

Science.gov (United States)

Chulan, Mohd Rizal Md; Yahaya, Redzuwan; Ghazali, Abu BakarMhd

2014-09-01

Shielding is an important aspect in the safety of an accelerator and the most important aspects of a bunker shielding is the door. The bunker's door should be designed properly to minimize the leakage radiation and shall not exceed the permitted limit of 2.5μSv/hr. In determining the leakage radiation dose that passed through the door and gaps between the door and the wall, 2-dimensional manual calculations are often used. This method is hard to perform because visual 2-dimensional is limited and is also very difficult in the real situation. Therefore estimation values are normally performed. In doing so, the construction cost would be higher because of overestimate or underestimate which require costly modification to the bunker. Therefore in this study, two methods are introduced to overcome the problem such as simulation using MCNPX Version 2.6.0 software and manual calculation using 3-dimensional model from Autodesk Inventor 2010 software. The values from the two methods were eventually compared to the real values from direct measurements using Ludlum Model 3 with Model 44-9 probe survey meter.

Determination of the dose equivalents due to neutrons produced during therapeutic irradiations with a Varian CLINAC 2500; Determinacion de la dosis equivalente debida a neutrones producidos durante irradiaciones terapeuticas con un Varian CLINAC 2500

Energy Technology Data Exchange (ETDEWEB)

Carrillo, Ricardo E [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Yucatan (Mexico)

1991-07-01

This experiment it was designed to quantify that so important it is the dose equivalent deposited by the neutron flow that is generated by photonuclear reactions during therapeutic irradiations with X rays of produced high-energy for an accelerator Varian CLINAC 2500. This accelerator type is routinely used in the Department of Radiotherapy of the Hospital of the University of Wisconsin, E.U. The equivalent dose was measured in diverse towns of the room of irradiations using the activation of thin sheets of gold put in the center of plastic recipients full with water. In general, the recipients were 1 m or more than the floor and at distances still bigger than the walls. The irradiations were made using photons with the highest energy that you can select with this team - 24 MeV. The due equivalent dose to neutrons taken place here by the energy photons used they were measured and reported. (author)

New generation of compact electron accelerators for radiation technologies

International Nuclear Information System (INIS)

Auslender, V.L.; Balakin, V.E.; Kraynov, G.S.

1995-01-01

Compact electron accelerators with energy range 0.25-1.0 MeV and beam power up to 32 kw are described. The feeding high voltage is formed by converter (working frequency 20 khz), coreless step-up transformer and a set of rectifying sections. The rectifying multiplier circuit used in rectifying sections permits to reach voltage gradient along accelerator's axis up to 14 kV/cm. The accelerators with vertical and horizontal position are described. The accelerators can be produced together with local radiation shielding and various underbeam transportation systems for irradiation of different products. Such version can be installed in any room facing general requirements for electric equipment

GPU - Accelerated Monte Carlo electron transport methods: development and application for radiation dose calculations using 6 GPU cards

International Nuclear Information System (INIS)

Su, L.; Du, X.; Liu, T.; Xu, X. G.

2013-01-01

An electron-photon coupled Monte Carlo code ARCHER - Accelerated Radiation-transport Computations in Heterogeneous EnviRonments - is being developed at Rensselaer Polytechnic Institute as a software test-bed for emerging heterogeneous high performance computers that utilize accelerators such as GPUs (Graphics Processing Units). This paper presents the preliminary code development and the testing involving radiation dose related problems. In particular, the paper discusses the electron transport simulations using the class-II condensed history method. The considered electron energy ranges from a few hundreds of keV to 30 MeV. As for photon part, photoelectric effect, Compton scattering and pair production were simulated. Voxelized geometry was supported. A serial CPU (Central Processing Unit)code was first written in C++. The code was then transplanted to the GPU using the CUDA C 5.0 standards. The hardware involved a desktop PC with an Intel Xeon X5660 CPU and six NVIDIA Tesla M2090 GPUs. The code was tested for a case of 20 MeV electron beam incident perpendicularly on a water-aluminum-water phantom. The depth and later dose profiles were found to agree with results obtained from well tested MC codes. Using six GPU cards, 6*10 6 electron histories were simulated within 2 seconds. In comparison, the same case running the EGSnrc and MCNPX codes required 1645 seconds and 9213 seconds, respectively. On-going work continues to test the code for different medical applications such as radiotherapy and brachytherapy. (authors)

Structural considerations for the practical development of primary shielding of X-ray rooms of megavoltage

International Nuclear Information System (INIS)

Lava, Deise D.; Borges, Diogo da S.; Affonso, Renato R.W.; Moreira, Maria de L.; Guimaraes, Antonio C.F.

2014-01-01

Due to the necessity of the use of accelerators with voltages above 10 MV in medical facilities, becomes necessary to evaluate the efficiency of the thickness of shielding materials used in rooms that contain these devices. This work presents the development of an algorithm able to provide data in a practical way, regarding the thickness of materials that can be used for an effective shielding against primary beams from these equipment. The use of the computer language C ++ allowed developing a practical tool for determining the thickness of materials required to protect the public and Individuals Occupationally Exposed (IOEs) against major powers beams. Furthermore, it was considered by calculations Intensity Modulated Radiotherapy Technique (IMRT). The construction of this tool was based to ensure the dose limits established in the CNEN-NN-3.01. The dose limiting is done through the use of loops able to validate the efficiency of thickness determined by the algorithm itself, and ensure if the radiation dose exceeds the limits set by the standard, it will be the inclusion of sufficient Half-Reducer Layers in so that the dose is within the parameters established by the Brazilian National Nuclear Energy Commission (CNEN). The code validation is performed by comparing results obtained in the examples p recalculated in the NCRP Report-151 (Structural Shielding Design and Evaluation for megavoltage X and Gamma-Ray Radiotherapy Facilities) with the results generated by the code. The results are satisfactory and consistent with that report

A collimated detection system for assessing leakage dose from medical linear accelerators at the patient plane.

Science.gov (United States)

Lonski, P; Taylor, M L; Franich, R D; Kron, T

2014-03-01

Leakage radiation from linear accelerators can make a significant contribution to healthy tissue dose in patients undergoing radiotherapy. In this work thermoluminescent dosimeters (LiF:Mg,Cu,P TLD chips) were used in a focused lead cone loaded with TLD chips for the purpose of evaluating leakage dose at the patient plane. By placing the TLDs at one end of a stereotactic cone, a focused measurement device is created; this was tested both in and out of the primary beam of a Varian 21-iX linac using 6 MV photons. Acrylic build up material of 1.2 cm thickness was used inside the cone and measurements made with either one or three TLD chips at a given distance from the target. Comparing the readings of three dosimeters in one plane inside the cone offered information regarding the orientation of the cone relative to a radiation source. Measurements in the patient plane with the linac gantry at various angles demonstrated that leakage dose was approximately 0.01% of the primary beam out of field when the cone was pointed directly towards the target and 0.0025% elsewhere (due to scatter within the gantry). No specific 'hot spots' (e.g., insufficient shielding or gaps at abutments) were observed. Focused cone measurements facilitate leakage dose measurements from the linac head directly at the patient plane and allow one to infer the fraction of leakage due to 'direct' photons (along the ray-path from the bremsstrahlung target) and that due to scattered photons.

A collimated detection system for assessing leakage dose from medical linear accelerators at the patient plane

International Nuclear Information System (INIS)

Lonski, P.; Kron, T.; Taylor, M.L.; Franich, R.D.

2014-01-01

Leakage radiation from linear accelerators can make a significant contribution to healthy tissue dose in patients undergoing radiotherapy. In this work thermoluminescent dosimeters (LiF:Mg,Cu,P TLD chips) were used in a focused lead cone loaded with TLD chips for the purpose of evaluating leakage dose at the patient plane. By placing the TLDs at one end of a stereotactic cone, a focused measurement device is created; this was tested both in and out of the primary beam of a Varian 21-iX linac using 6 MV photons. Acrylic build up material of 1.2 cm thickness was used inside the cone and measurements made with either one or three TLD chips at a given distance from the target. Comparing the readings of three dosimeters in one plane inside the cone offered information regarding the orientation of the cone relative to a radiation source. Measurements in the patient plane with the linac gantry at various angles demonstrated that leakage dose was approximately 0.01 % of the primary beam out of field when the cone was pointed directly towards the target and 0.0025 % elsewhere (due to scatter within the gantry). No specific ‘hot spots’ (e.g., insufficient shielding or gaps at abutments) were observed. Focused cone measurements facilitate leakage dose measurements from the linac head directly at the patient plane and allow one to infer the fraction of leakage due to ‘direct’ photons (along the ray-path from the bremsstrahlung target) and that due to scattered photons.

Normal tissue complication models for clinically relevant acute esophagitis (≥ grade 2) in patients treated with dose differentiated accelerated radiotherapy (DART-bid)

International Nuclear Information System (INIS)

Zehentmayr, Franz; Söhn, Matthias; Exeli, Ann-Katrin; Wurstbauer, Karl; Tröller, Almut; Deutschmann, Heinz; Fastner, Gerd; Fussl, Christoph; Steininger, Philipp; Kranzinger, Manfred; Belka, Claus; Studnicka, Michael; Sedlmayer, Felix

2015-01-01

One of the primary dose-limiting toxicities during thoracic irradiation is acute esophagitis (AE). The aim of this study is to investigate dosimetric and clinical predictors for AE grade ≥ 2 in patients treated with accelerated radiotherapy for locally advanced non-small cell lung cancer (NSCLC). 66 NSCLC patients were included in the present analysis: 4 stage II, 44 stage IIIA and 18 stage IIIB. All patients received induction chemotherapy followed by dose differentiated accelerated radiotherapy (DART-bid). Depending on size (mean of three perpendicular diameters) tumors were binned in four dose groups: <2.5 cm 73.8 Gy, 2.5–4.5 cm 79.2 Gy, 4.5–6 cm 84.6 Gy, >6 cm 90 Gy. Patients were treated in 3D target splitting technique. In order to estimate the normal tissue complication probability (NTCP), two Lyman models and the cutoff-logistic regression model were fitted to the data with AE ≥ grade 2 as statistical endpoint. Inter-model comparison was performed with the corrected Akaike information criterion (AIC c ), which calculates the model’s quality of fit (likelihood value) in relation to its complexity (i.e. number of variables in the model) corrected by the number of patients in the dataset. Toxicity was documented prospectively according to RTOG. The median follow up was 686 days (range 84–2921 days), 23/66 patients (35 %) experienced AE ≥ grade 2. The actuarial local control rates were 72.6 % and 59.4 % at 2 and 3 years, regional control was 91 % at both time points. The Lyman-MED model (D50 = 32.8 Gy, m = 0.48) and the cutoff dose model (D c = 38 Gy) provide the most efficient fit to the current dataset. On multivariate analysis V38 (volume of the esophagus that receives 38 Gy or above, 95 %-CI 28.2–57.3) was the most significant predictor of AE ≥ grade 2 (HR = 1.05, CI 1.01–1.09, p = 0.007). Following high-dose accelerated radiotherapy the rate of AE ≥ grade 2 is slightly lower than reported for concomitant radio-chemotherapy with the

Radiation Protection Elephants in the Room

International Nuclear Information System (INIS)

Vetter, R. J.

2004-01-01

As our system of radiological protection evolves, several significant issues loom within radiation protection discussions and publications. These issues influence the nature of epidemiological and radiobiological research and the establishment of radiation protection recommendations, standards, and regulations. These issues are like the proverbial e lephants in the room . They are large, and it is unwise to ignore them. This paper discusses the impact of three young elephants as they make their presence increasingly obvious: increased cancer susceptibility from early-life exposure to radiation, terrorism and fear of radiation, and patient safety. Increased cancer susceptibility from early-life exposure to radiation is emerging as a discussion topic related to the safety of computed tomography (CT) and other medical modalities. Shortly after publication of CT dose data, manufacturers were helping to reduce doses to children by increasing flexibility for adjustment of technique factors. Also, radiation epidemiological data are being used in the development of guidance on exposure to chemical carcinogens during early life. Re-emergence of public fear of radiation has been fueled by threats of radiological dispersion devises and confusing messages about personal decontamination, emergency room acceptance or rejection of contaminated victims, and environmental clean-up. Finally, several professional publications have characterized risk of medical radiation exposure in terms of patient deaths even though epidemiological data do not support such conclusions. All three of these elephants require excellent science and sophisticated data analysis to coax them from the room. Anecdotal communications that confuse the public should be avoided. These are not the only elephants in the room, but these three are making their presence increasingly obvious. This paper discusses the need for radiation protection professionals to rely on good science in the evolution of the system of

INVESTIGATION OF SECONDARY MIXED RADIATION FIELD AROUND A MEDICAL LINEAR ACCELERATOR.

Science.gov (United States)

Tulik, Piotr; Tulik, Monika; Maciak, Maciej; Golnik, Natalia; Kabat, Damian; Byrski, Tomasz; Lesiak, Jan

2017-09-29

The aim of this study is to investigate secondary mixed radiation field around linac, as the first part of an overall assessment of out-of-field contribution of neutron dose for new advanced radiation dose delivery techniques. All measurements were performed around Varian Clinic 2300 C/D accelerator at Maria Sklodowska-Curie Memorial, Cancer Center and Institute of Oncology, Krakow Branch. Recombination chambers REM-2 and GW2 were used for recombination index of radiation quality Q4 determination (as an estimate of quality factor Q), measurement of total tissue dose Dt and calculation of gamma and neutron components to Dt. Estimation of Dt and Q4 allowed for the ambient dose equivalent H*(10) per monitor unit (MU) calculations. Measurements around linac were performed on the height of the middle of the linac's head (three positions) and on the height of the linac's isocentre (five positions). Estimation of secondary radiation level was carried out for seven different configurations of upper and lower jaws position and multileaf collimator set open or closed in each position. Study includes the use of two photon beam modes: 6 and 18 MV. Spatial distribution of ambient dose equivalent H*(10) per MU on the height of the linac's head and on the standard couch height for patients during the routine treatment, as well as relative contribution of gamma and neutron secondary radiation inside treatment room were evaluated. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ambient dose measurement in some CT departments in Khartoum State

International Nuclear Information System (INIS)

Mohammed, S. A. H.

2012-09-01

Computerized Tomography (CT) is now one of the most important radiological examinations world wide.The frequency of CT examinations is increasing rapidly from 2% of all radiological examinations in some countries a decade age to 10-15% now. During the imaging procedure, staff may expose to a significant dose. Therefore, ambient dose measurement is important in the shortage of regular personal monitoring in sudan. This study intended to evaluate the ambient dose at some CT departments (Medical Military hospital, Alamal National Hospital, Elnelin Diagnostic Center and Modern Medical Centre). These departments were equipped with daul, 16 and 64 multi detector CT machines. A survey meter (Radios) was used to measure ambient doses in three locations: Doors, Control Rooms and Adjacent Rooms. The ambient dose equivalent (scatter dose) was measured at various distances from the isocenter of the CT unit at various angles to establish isodose cartography. The mean and range of radiation at control room is 10.00-0.20 and mean (7.05μSv/hr,) reception 1.0-0 (0.40) and doors 4.00-100.00 (73.5) for height 1 meter above the ground. For height 2 meters at control room 0-10.00 (6,75), reception 0-90.00 (30) at door 9.00-90.00 (49.50). This study confirms that low levels of radiation dose are received by staff during CT imaging and these levels are within safe limits as prescribed by the national and international regulations. (Author)

An electronic logbook for the HEP control room

International Nuclear Information System (INIS)

Roediger, G.; Pomatto, P.; Kyriakopulos, J.; Panacek, S.; Canal, P.; Kubarovsky, A.

2001-01-01

The Control Room Logbook (CRL) is designed to improve and replace the paper logbooks traditionally used in the HEP accelerator control room. Its features benefit the on-line coordinator, the shift operators, and the remote observers. The author explains some of the most attractive features for each of these roles. The features include the ability to configure the logbook for the specific needs of a collaboration, a large variety of entry types an operator can add by simply clicking and dragging, and a flexible web interface for the remote observer to keep up with control room activities. The entries and saved as UTF-8 based XML files, which allowed us to give the data structure and meaning such that it can easily be parsed in the present and far into the future. The XML tag data is also indexed in a relational database, making queries on dates, keywords, entry type and other criteria feasible and fast. The CRL is used in the D0 control room. This presentation also discusses our experience with deployment, platform independence and other interesting issues that arose with the installation and use of logbook

An Electronic Logbook for the HEP Control Room

International Nuclear Information System (INIS)

Gary Roediger

2001-01-01

The Control Room Logbook (CRL) is designed to improve and replace the paper logbooks traditionally used in the HEP accelerator control room. Its features benefit the on-line coordinator, the shift operators, and the remote observers. This paper explains some of the most attractive features for each of these roles. The features include the ability to configure the logbook for the specific needs of a collaboration, a large variety of entry types an operator can add by simply clicking and dragging, and a flexible web interface for the remote observer to keep up with control room activities. The entries are saved as UTF-8 based XML files, which allowed us to give the data structure and meaning such that it can easily be parsed in the present and far into the future. The XML tag data is also indexed in a relational database, making queries on dates, keywords, entry type and other criteria feasible and fast. The CRL is used in the D0 control room. This presentation also discusses our experience with deployment, platform independence and other interesting issues that arose with the installation and use of the logbook

Reduction in life span on normal human fibroblasts exposed to low-dose radiation in heavy-ion radiation field

International Nuclear Information System (INIS)

Suzuki, Masao; Yamaguchi, Chizuru; Yasuda, Hiroshi; Uchihori, Yukio; Fujitaka, Kazunobu

2003-01-01

We studied the effect of in vitro life span in normal human fibroblasts exposed to chronically low-dose radiation in heavy-ion radiation field. Cells were cultured in a CO 2 incubator, which was set in the irradiation room for biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and exposed to scattered radiations produced with heavy-ion beams throughout the life span of the cell population. Absorbed dose, which was measured using a thermoluminescence dosimeter(TLD) and a Si-semiconductor detector, was to be 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number of the exposed cells reduced to 79-93% of non-exposed control cells in the three independent experiments. There is evidence that the exposure of chronically low-dose radiation in heavy-ion radiation field promotes the life-span reduction in cellular level. (author)

Study on indoor radon concentration and gamma radiation dose rate in different rooms in some dwellings around Bharath Gold Mines Limited, Karnataka State, India

International Nuclear Information System (INIS)

Umesha Reddy, K.; Jayasheelan, A.; Sannappa, J.

2012-01-01

Indoor radon contributes significantly to the total radiation exposure caused to human beings. The indoor concentration of radon in different rooms in the same type of dwellings around Bharath Gold Mines Limited (BGML), Karnataka State (12°57' min N and 78°16' min E) were measured by using LR-115 (type-Il) Solid State Nuclear Track Detectors (SSNTDs). The maximum indoor radon concentration is observed in the bathroom and minimum in the hall. The maximum average indoor radon concentration is observed in the Champion and minimum in the BEML nagar. The indoor gamma radiation dose rate is also measured in these locations using scintillometer. The geology of this part forms predominantly Hornblende Schist, Granite gneiss, Champion gneiss, Quartzite etc. The indoor radon concentration shows good correlation with the indoor gamma radiation dose. (author)

Phase space determination from measured dose data for intraoperative electron radiation therapy.

Science.gov (United States)

Herranz, E; Herraiz, J L; Ibáñez, P; Pérez-Liva, M; Puebla, R; Cal-González, J; Guerra, P; Rodríguez, R; Illana, C; Udías, J M

2015-01-07

A procedure to characterize beams of a medical linear accelerator for their use in Monte Carlo (MC) dose calculations for intraoperative electron radiation therapy (IOERT) is presented. The procedure relies on dose measurements in homogeneous media as input, avoiding the need for detailed simulations of the accelerator head. An iterative algorithm (EM-ML) has been employed to extract the relevant details of the phase space (PHSP) of the particles coming from the accelerator, such as energy spectra, spatial distribution and angle of emission of particles. The algorithm can use pre-computed dose volumes in water and/or air, so that the machine-specific tuning with actual data can be performed in a few minutes. To test the procedure, MC simulations of a linear accelerator with typical IOERT applicators and energies, have been performed and taken as reference. A solution PHSP derived from the dose produced by the simulated accelerator has been compared to the reference PHSP. Further, dose delivered by the simulated accelerator for setups not included in the fit of the PHSP were compared to the ones derived from the solution PHSP. The results show that it is possible to derive from dose measurements PHSP accurate for IOERT MC dose estimations.

Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

Energy Technology Data Exchange (ETDEWEB)

Schandorf, C.; Tetteh, G.K

1998-07-01

The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

International Nuclear Information System (INIS)

Schandorf, C.; Tetteh, G.K.

1998-01-01

The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

Evaluation of worker's dose on a virtual dismantling environment

International Nuclear Information System (INIS)

Park, Hee Seong; Kim, Sung Hyun; Park, Byung Suk; Yoon, Ji Sup

2007-01-01

The motivation of this study is to provide a basis for a minimization of worker's dose during dismantling activities. In the present study, we proposed methods for identifying an existence of radioactivity which is contained in the dismantling objects and for evaluating a worker's dose under a virtual dismantling environment. To evaluate a worker's external dose, the shape of the exposure room in the KRR 2(Korean Research Reactor TRIGA MARK III) by 3D CAD was created and the radiation dose surrounding the facility by using MCNP- 4C(Monte Carlo N-Particle-4C) was calculated. The radiation field of the exposure room was visualized three dimensionally by using the radiation dose that was obtained by the code

Post-accelerator LINAC design for the VECC RIB project

Indian Academy of Sciences (India)

acclerator type of RIB facility. The scheme utilises the existing = 130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency quadrupole (RFQ) and LINAC modules for ...

Calculations for Extra Well Shielding for 15 MV Clinical Linear accelerator

International Nuclear Information System (INIS)

Mahmoud, M.A.; Emran, M.M.; Ahmad, A.S.

2000-01-01

A radiological survey was conducted around the walls of a clinical linear accelerator (Siemens Mevatron) in South Egypt Cancer Institute, Assiut University. Neutron measurements showed adequate results for all beam orientations. Photon measurements showed adequate results for all beam orientations except for beam orientation 270 degree, facing the control room. During operation, photon measurements were taken in order to calculate the additional shield thickness required to reduce measurements to accepted values. For convenience, lead was the material of choice for extra shielding. A value for the build up factor needed in the calculations of broad beam attenuation was estimated. Measurements inside the control room after adding the calculated lead thickness are much lower than the annual effective equivalent dose limits recommended by the ICRP-60 (International Commission on Radiation Protection) for occupational exposure. Also, measurements taken in the patients waiting hall recorded levels consistent with the six-hour daily occupancy for members of the public. The value of the build up factor was verified by calculations. Also the variation of build up factor distance from the field centre was calculated. Important and useful recommendations were reached from this experience which should be discussed to avoid facing similar situations in radiotherapy departments in Egypt

Comparison of Dose Distributions With TG-43 and Collapsed Cone Convolution Algorithms Applied to Accelerated Partial Breast Irradiation Patient Plans

Energy Technology Data Exchange (ETDEWEB)

Thrower, Sara L., E-mail: slloupot@mdanderson.org [The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Shaitelman, Simona F.; Bloom, Elizabeth [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Salehpour, Mohammad; Gifford, Kent [Department of Radiation Physics, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

2016-08-01

Purpose: To compare the treatment plans for accelerated partial breast irradiation calculated by the new commercially available collapsed cone convolution (CCC) and current standard TG-43–based algorithms for 50 patients treated at our institution with either a Strut-Adjusted Volume Implant (SAVI) or Contura device. Methods and Materials: We recalculated target coverage, volume of highly dosed normal tissue, and dose to organs at risk (ribs, skin, and lung) with each algorithm. For 1 case an artificial air pocket was added to simulate 10% nonconformance. We performed a Wilcoxon signed rank test to determine the median differences in the clinical indices V90, V95, V100, V150, V200, and highest-dosed 0.1 cm{sup 3} and 1.0 cm{sup 3} of rib, skin, and lung between the two algorithms. Results: The CCC algorithm calculated lower values on average for all dose-volume histogram parameters. Across the entire patient cohort, the median difference in the clinical indices calculated by the 2 algorithms was <10% for dose to organs at risk, <5% for target volume coverage (V90, V95, and V100), and <4 cm{sup 3} for dose to normal breast tissue (V150 and V200). No discernable difference was seen in the nonconformance case. Conclusions: We found that on average over our patient population CCC calculated (<10%) lower doses than TG-43. These results should inform clinicians as they prepare for the transition to heterogeneous dose calculation algorithms and determine whether clinical tolerance limits warrant modification.

Measurements of dose on build-up region, surface dose and outlet dose by a 10 MeV Linear accelerator

International Nuclear Information System (INIS)

Souza, C.N. de; Khoury, H.J.

1987-01-01

The dose on buildup region and the surface dose for a 10 MeV photon beam from a linear acelerator (Mevatrom-74, Siemens) is studied. The influence of the tray of polycarbonate on the surface dose is determined. (M.A.C.) [pt

Accelerators and associated infrastructure at IUAC

International Nuclear Information System (INIS)

Roy, Amit

2009-01-01

Full text: The 15UD Pelletron accelerator forms the heart of the core facilities of IUAC and has been in regular operation round the clock, 7 days a week except during maintenance periods with a remarkable uptime of more than 90% since July 1991. The accelerator augmentation programme intends to provide superconducting linear accelerator modules to boost the energy of ions in the range of 500-600 MeV. On-line beam acceleration with superbuncher, first linac module and rebuncher was successfully conducted and first nuclear physics experiment was performed using this beam. The fabrication of the second and third linac modules with sixteen resonators is going on in full swing and construction is expected to be completed within this year. The first element of the high current injector is a High Tc superconducting magnet ECR source, which would be followed by a room temperature radio frequency quadrupole accelerator and drift tube linac cavities. Prototypes of the RFQ working at 48.5 MHz, and that of the DTL working at 97 MHz have been fabricated and undergoing tests. (author)

Online monitoring of absorbed dose in undulator magnets with RADFET dosimeters at FERMI@Elettra

International Nuclear Information System (INIS)

Fröhlich, L.; Casarin, K.; Quai, E.; Holmes-Siedle, A.; Severgnini, M.; Vidimari, R.

2013-01-01

The FERMI@Elettra free-electron laser, based on a 1.3 GeV electron linac, requires the monitoring of radiation doses up to a few kGy for the protection of sensitive equipment such as permanent magnet undulators. A new dosimetry system DOSFET-L01, employing an array of RADFETs spread throughout the accelerator, was developed. So far, the system has performed flawlessly for almost two years, taking one dose reading per minute around the clock. The REM RFT-300 sensors were set in zero-bias mode, i.e. with all electrodes grounded during exposure. This choice of mode allows the measurement of a high range of integrated doses – up to a few kGy. The paper describes the new read-out system and its application, calibration measurements in cobalt-60 and 6 MeV bremsstrahlung radiation sources giving rise to a novel response function, and new data on “fade” under the zero-bias mode of use for over 300 days at room temperature. Regular readings from 28 RADFETs placed within seven undulators over the first 20 months of operation of the accelerator demonstrate how the system tracks and locates periods of high and low dose rate and thereby contributes to the protection from beam loss. The readings from the RADFET system are found to be in good agreement with Gafchromic EBT2 film dosimeters. Based on the results reported, the choice of bias mode may be revised so as to reduce fade and improve the accuracy conferred by a positive-bias mode. -- Highlights: ► We developed a system for online dosimetry with RADFET sensors under zero bias. ► The system is calibrated for doses up to 10 kGy with REM RFT-300 sensors. ► We collected data on fade for over 300 days from irradiation. ► We present undulator dose measurements for 20 months of operation of FERMI@Elettra. ► Dose measurements are in good agreement with chemical film dosimeters

Preservation and release dose of helium implanted in nanocrystal titanium film

International Nuclear Information System (INIS)

Long Xinggui; Luo Shunzhong; Peng Shuming; Zheng Sixiao; Liu Zhongyang; Wang Peilu; Liao Xiaodong; Liu Ning

2003-01-01

Helium concentration profile, preservation dose and release rate from a nanocrystal titanium film implanted with helium at an energy of 100 keV and dose of 2.2 x 10 18 cm -2 are measured by proton Rutherford backscattering technique in a range from room temperature to 400 degree C. The implanted helium may be stably preserved up to the 68 percent after keeping a long time of 210 d in the nanocrystal titanium film at the room temperature environment, and the He-Ti atomic ratio reaches to 52.6%. When the temperature of specimen increases to 100 degree C, the helium concentration can be preserved to 89.6% of the keeping helium dose at room temperature and He-Ti atomic ratio reaches 44%. Even if the specimen temperature up to 400 degree C, the helium concentration still can be preserved to 32.6% of the keeping helium dose at room temperature and the He-Ti atomic ratio is 17.1%. Possible mechanism of helium effectively preserved in the nanocrystal titanium film is discussed based on the energy stability viewpoint

Simulation of a room for neutron instrument calibration at LCR/UERJ

International Nuclear Information System (INIS)

Medeiros, M.P.C.; Estrada, J.J.S.; Gomes, R.G.; Santos, R.F.G.; Leite, S.P.; Alves, C.F.E.; Rebello, W.F.; Almeida, C.E. de

2013-01-01

In this work the MCNPX code was used to design a calibrating room for neutron detectors to be implemented in the Laboratorio de Ciencias Radiologicas of UERJ. The calibration room containing a neutron irradiator with a 241 Am-Be source, a linear positioning system, radiation detectors and a shadow cone was modeled. The ambient dose equivalent rate, ııı ∗ ı10ı, in adjacent to the calibration room areas, as well as neutron scattering caused by the room itself were calculated. Using an occupancy factor of 1/16 for all adjacent areas, 3.8 cm of 5% borated polyethylene or 5.5 cm of concrete for shielding is enough to satisfy radiation safety requirements. (author)

Development and characterization of an interferometer for calorimeter-based absorbed dose to water measurements in a medical linear accelerator.

Science.gov (United States)

Flores-Martinez, Everardo; Malin, Martha J; DeWerd, Larry A

2016-11-01

The quantity of relevance for external beam radiotherapy is absorbed dose to water (ADW). An interferometer was built, characterized, and tested to measure ADW within the dose range of interest for external beam radiotherapy using the temperature dependence of the refractive index of water. The interferometer was used to measure radiation-induced phase shifts of a laser beam passing through a (10 × 10 × 10) cm 3 water-filled glass phantom, irradiated with a 6 MV photon beam from a medical linear accelerator. The field size was (7 × 7) cm 2 and the dose was measured at a depth of 5 cm in the water phantom. The intensity of the interference pattern was measured with a photodiode and was used to calculate the time-dependent phase shift curve. The system was thermally insulated to achieve temperature drifts of less than 1.5 mK/min. Data were acquired 60 s before and after the irradiation. The radiation-induced phase shifts were calculated by taking the difference in the pre- and post-irradiation drifts extrapolated to the midpoint of the irradiation. For 200, 300, and 400 monitor units, the measured doses were 1.6 ± 0.3, 2.6 ± 0.3, and 3.1 ± 0.3 Gy, respectively. Measurements agreed within the uncertainty with dose calculations performed with a treatment planning system. The estimated type-A, k = 1 uncertainty in the measured doses was 0.3 Gy which is an order of magnitude lower than previously published interferometer-based ADW measurements.

Re-envisioning the operator consoles for Dhruva control room

International Nuclear Information System (INIS)

Gaur, S.; Sridharan, P.; Nair, P.M.; Diwakar, M.P.; Gohel, N.; Pithawa, C.K.

2012-01-01

Control Room design is undergoing rapid changes with the progressive adoption of computerization and Automation. Advances in man-machine interfaces have further accelerated this trend. This paper presents the design and main features of Operator consoles (OC) for Dhruva control room developed using new technologies. The OCs have been designed so as not to burden the operator with information overload but to help him quickly assess the situation and timely take appropriate steps. The consoles provide minimalistic yet intuitive interfaces, context sensitive navigation, display of important information and progressive disclosure of situation based information. The use of animations, 3D graphics, and real time trends with the benefit of hardware acceleration to provide a resolution independent rich user experience. The use of XAML, an XML based Mark-up Language for User Interface definition and C for application logic resulted in complete separation of visual design, content, and logic. This also resulted in a workflow where separate teams could work on the UI and the logic of an application. The introduction of Model View View-Model has led to more testable and maintainable software. (author)

Dose profile of a dental facilities

International Nuclear Information System (INIS)

Silva Borges, D. da; Lava, D.D.; Moreira, M. de L.; Ferreira Guimaraes, A.C.; Silva, L. Fernandes da

2015-01-01

The determination of the dose profile is important to classify the level of danger which the individuals are exposed (considering their positioning) in dental facilities. From this, this paper aims to present a methodology capable of mapping the dose within dental rooms in three dimensions. The methodology used for dose mapping in conjunction with techniques for calculating shielding for dental facilities, provided by the National Council on Radiation Protection and Measurements (NCRP), form a complete system able to generate meaningful data on the safety of occupationally Exposed Individuals (IOEs) and of the public. As the dose is strongly dependent on the distance, the estimated value of the initial dose was made in the isocenter of the source. This value was adopted because the model of dose calculus tends to infinity when it is desired to analyze points very close of the source. The model of room to be presented, as a case of illustration of the methodology, was arbitrarily constructed to generate better understanding of the problem. Its inclusion in the calculus was made through discretizations performed with the aid of high-performance computers. This discretizations allowed the obtain of dose values for an infinitesimal distance after the start point. (authors)

Accelerating Energy Efficiency Improvements in Room Air Conditioners in India: Potential, Costs-Benefits, and Policies

OpenAIRE

Abhyankar, N; Shah, N; Park, WY; Phadke, AA

2017-01-01

Rising incomes, increasing urbanization, and large cooling demand prompted by India’s hot, humid climate are driving increasing uptake of room air conditioners (ACs). Air conditioning already accounts for 40-60% of summer peak load in large Indian cities such as Delhi and is on track to contribute 140 gigawatts (GW) ( 30%) to peak demand in 2030. India’s standards and labeling policies improved the market average efficiency of room ACs by about 35% between 2006 and 2016 (3% per year) even as ...

Dosimetry of laser-accelerated electron beams used for in vitro cell irradiation experiments

International Nuclear Information System (INIS)

Richter, C.; Kaluza, M.; Karsch, L.; Schlenvoigt, H.-P.; Schürer, M.; Sobiella, M.; Woithe, J.; Pawelke, J.

2011-01-01

The dosimetric characterization of laser-accelerated electrons applied for the worldwide first systematic radiobiological in vitro cell irradiation will be presented. The laser-accelerated electron beam at the JeTi laser system has been optimized, monitored and controlled in terms of dose homogeneity, stability and absolute dose delivery. A combination of different dosimetric components were used to provide both an online beam as well as dose monitoring and a precise absolute dosimetry. In detail, the electron beam was controlled and monitored by means of an ionization chamber and an in-house produced Faraday cup for a defined delivery of the prescribed dose. Moreover, the precise absolute dose delivered to each cell sample was determined by an radiochromic EBT film positioned in front of the cell sample. Furthermore, the energy spectrum of the laser-accelerated electron beam was determined. As presented in a previous work of the authors, also for laser-accelerated protons a precise dosimetric characterization was performed that enabled initial radiobiological cell irradiation experiments with laser-accelerated protons. Therefore, a precise dosimetric characterization, optimization and control of laser-accelerated and therefore ultra-short pulsed, intense particle beams for both electrons and protons is possible, allowing radiobiological experiments and meeting all necessary requirements like homogeneity, stability and precise dose delivery. In order to fulfill the much higher dosimetric requirements for clinical application, several improvements concerning, i.e., particle energy and spectral shaping as well as patient safety are necessary.

A study on leakage radiation dose at ELV-4 electron accelerator bunker

Energy Technology Data Exchange (ETDEWEB)

Chulan, Mohd Rizal Md, E-mail: rizal@nuclearmalaysia.gov.my, E-mail: redzuwan@ukm.my; Yahaya, Redzuwan, E-mail: rizal@nuclearmalaysia.gov.my, E-mail: redzuwan@ukm.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (Malaysia); Ghazali, Abu BakarMhd [Department of Electronic and Communication, College of Engineering, Universiti Tenaga Nasional (Malaysia)

2014-09-03

Shielding is an important aspect in the safety of an accelerator and the most important aspects of a bunker shielding is the door. The bunker’s door should be designed properly to minimize the leakage radiation and shall not exceed the permitted limit of 2.5μSv/hr. In determining the leakage radiation dose that passed through the door and gaps between the door and the wall, 2-dimensional manual calculations are often used. This method is hard to perform because visual 2-dimensional is limited and is also very difficult in the real situation. Therefore estimation values are normally performed. In doing so, the construction cost would be higher because of overestimate or underestimate which require costly modification to the bunker. Therefore in this study, two methods are introduced to overcome the problem such as simulation using MCNPX Version 2.6.0 software and manual calculation using 3-dimensional model from Autodesk Inventor 2010 software. The values from the two methods were eventually compared to the real values from direct measurements using Ludlum Model 3 with Model 44-9 probe survey meter.

A study on leakage radiation dose at ELV-4 electron accelerator bunker

International Nuclear Information System (INIS)

Chulan, Mohd Rizal Md; Yahaya, Redzuwan; Ghazali, Abu BakarMhd

2014-01-01

Shielding is an important aspect in the safety of an accelerator and the most important aspects of a bunker shielding is the door. The bunker’s door should be designed properly to minimize the leakage radiation and shall not exceed the permitted limit of 2.5μSv/hr. In determining the leakage radiation dose that passed through the door and gaps between the door and the wall, 2-dimensional manual calculations are often used. This method is hard to perform because visual 2-dimensional is limited and is also very difficult in the real situation. Therefore estimation values are normally performed. In doing so, the construction cost would be higher because of overestimate or underestimate which require costly modification to the bunker. Therefore in this study, two methods are introduced to overcome the problem such as simulation using MCNPX Version 2.6.0 software and manual calculation using 3-dimensional model from Autodesk Inventor 2010 software. The values from the two methods were eventually compared to the real values from direct measurements using Ludlum Model 3 with Model 44-9 probe survey meter

Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

International Nuclear Information System (INIS)

Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

2016-01-01

The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit. - Highlights: • A 3/6 MeV electron accelerator equipped with a high energy x-ray target was studied. • Monte Carlo modeling of photon flux was carried out for three accelerator configurations. • Human biological equivalent doses were evaluated within the accelerator facility building.

Assessment of control room habitability and unfiltered air inleakage test of the OPR 1000 NPP

International Nuclear Information System (INIS)

Song, Dong Soo; Lee, Jong Beom; Ha, Sang Jun; Huh, Seong Cheol

2015-01-01

The assessment of control room habitability for Hanbit unit 5 was performed based on GL 2003-01 and Regulatory Guide 1.197. The integrated control room envelope (CRE) test was performed utilizing ASTM E741. Four tests were performed using each of the control room HVAC subtrains. The control room heating, ventilating, and air conditioning (HVAC) system lineup of pressurization mode test was based upon a lineup that encompassed the design basis radiological analyses. The other control room HVAC system lineup of isolation mode test was based on an operation mode that considers toxic gas. The measured inleakage for the isolation test mode remains within the toxicity limit. Radiation effect analysis showed that the measured inleakage satisfied the regulatory criteria, and the inleakage would not result in control room operator dose exceeding 50 mSv whole body and 500 mSv thyroid except train A pressurization test mode. The thyroid dose due to maximum measured unfiltered inleakage of 8976 lpm for train A is corresponding to 700 mSv. Modifications to the CRE boundary and control room HVAC system should be done to demonstrate that the measured unfiltered inleakage for train A pressurization test mode is bounded by the regulatory criteria assumed in the design basis radiological analyses. (author)

Electron accelerator shielding design of KIPT neutron source facility

Energy Technology Data Exchange (ETDEWEB)

Zhong, Zhao Peng; Gohar, Yousry [Argonne National Laboratory, Argonne (United States)

2016-06-15

The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose

CERN opens up its control rooms to youngsters

CERN Multimedia

CERN Bulletin

2011-01-01

CERN is inviting 13 to 18 year-olds to come and spend a couple of hours in the control rooms of the LHC and its experiments. Registration is now open.   Is your neighbour's kid eager to come and see what's going on in the CERN control rooms for himself? Is your niece from Germany fascinated by the famous accelerator near Geneva that she's heard about and asking to know more? Then Researchers Night is for them! From 6.00 p.m. on Friday 23 September until 1.00 a.m. the following morning, the LHC and its experiments will open their doors to 13 to 18 year-olds. They are invited to come and spend a couple of hours in the control rooms watching the physicists and taking part in various activities. ALICE, ATLAS, CMS, LHCb, TOTEM, and the CERN Control Centre (CCC) will all be welcoming visitors. For this second year of CERN's involvement in European Researchers Night, the CERN exhibitions will be open late and special activities will be organised in Microcosm....

Adjoint acceleration of Monte Carlo simulations using TORT/MCNP coupling approach: A case study on the shielding improvement for the cyclotron room of the Buddhist Tzu Chi General Hospital

International Nuclear Information System (INIS)

Sheu, R. J.; Sheu, R. D.; Jiang, S. H.; Kao, C. H.

2005-01-01

Full-scale Monte Carlo simulations of the cyclotron room of the Buddhist Tzu Chi General Hospital were carried out to improve the original inadequate maze design. Variance reduction techniques are indispensable in this study to facilitate the simulations for testing a variety of configurations of shielding modification. The TORT/MCNP manual coupling approach based on the Consistent Adjoint Driven Importance Sampling (CADIS) methodology has been used throughout this study. The CADIS utilises the source and transport biasing in a consistent manner. With this method, the computational efficiency was increased significantly by more than two orders of magnitude and the statistical convergence was also improved compared to the unbiased Monte Carlo run. This paper describes the shielding problem encountered, the procedure for coupling the TORT and MCNP codes to accelerate the calculations and the calculation results for the original and improved shielding designs. In order to verify the calculation results and seek additional accelerations, sensitivity studies on the space-dependent and energy-dependent parameters were also conducted. (authors)

Research on cw electron accelerators using room-temperature rf structures. Annual report

International Nuclear Information System (INIS)

1985-01-01

Highlights reported include: measurement of the 100 keV chopped beam emittance, completion of installation of the entire 5 MeV injector linac system with all rf power and drive, extensive field mapping of one end magnet, completion of construction of the 12 MeV linac for the racetrack microtron (RTM), installation of most of the control system, and first acceleration of beam to 5 MeV. Plans for completion of the project are discussed. When the RTM is operating, it is expected to have many unique performance characteristics, including the cw nature of the beam, high current, easily variable energy over a wide range, excellent emittance, and small energy spread. Plans for future uses in the areas of nuclear physics, dosimetry research and standards, accelerator development, and free electron laser research are discussed. 19 refs

Dose distributions in electron irradiated plastic tubing

International Nuclear Information System (INIS)

Miller, A.; Pederson, W.B.

1981-01-01

Plastic tubes have been crosslinked by irradiation at a 10 MeV linear electron accelerator and at a 400 keV DC electron accelerator at different irradiation geometries. The diameter of the different tubes was 20, 33 and 110 millimeters. Dose distributions have been measured with thin radiochromic dye films, indicating that in all cases irradiation from two sides is a necessary and sufficient condition for obtaining a satisfactory dose distribution. (author)

PET/CT-guided Interventions: Personnel Radiation Dose

Energy Technology Data Exchange (ETDEWEB)

Ryan, E. Ronan, E-mail: ronan@ronanryan.com; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Hsu, Meier [Memorial Sloan-Kettering Cancer Center, Department of Epidemiology and Biostatistics (United States); Quinn, Brian; Dauer, Lawrence T. [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics (United States); Solomon, Stephen B. [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States)

2013-08-01

PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0-0.13) mSv for the primary operator, 0.01 (range 0-0.05) mSv for the nurse anesthetist, and 0.02 (range 0-0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0-0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.

In defence of collective dose

International Nuclear Information System (INIS)

Fairlie, I.; Sumner, D.

2000-01-01

Recent proposals for a new scheme of radiation protection leave little room for collective dose estimations. This article discusses the history and present use of collective doses for occupational, ALARA, EIS and other purposes with reference to practical industry papers and government reports. The linear no-threshold (LNT) hypothesis suggests that collective doses which consist of very small doses added together should be used. Moral and ethical questions are discussed, particularly the emphasis on individual doses to the exclusion of societal risks, uncertainty over effects into the distant future and hesitation over calculating collective detriments. It is concluded that for moral, practical and legal reasons, collective dose is a valid parameter which should continue to be used. (author)

Radiation response of industrial materials: Dose-rate and morphology implications

International Nuclear Information System (INIS)

Berejka, Anthony J.

2007-01-01

Industrial uses of ionizing radiation mostly rely upon high current, high dose-rate (100 kGy/s) electron beam (EB) accelerators. To a lesser extent, industry uses low dose-rate (2.8 x 10 -3 kGy/s) radioactive Cobalt-60 as a gamma source, generally for some rather specific purposes, as medical device sterilization and the treatment of food and foodstuffs. There are nearly nine times as many (∼1400) high current EB units in commercial operation than gamma sources (∼160). However, gamma sources can be easily scaled-down so that much research on materials effects is conducted using gamma radiation. Likewise, laboratories are more likely to have very low beam current and consequently low dose-rate accelerators such as Van de Graaff generators and linear accelerators. With the advent of very high current EB accelerators, X-ray processing has become an industrially viable option. With X-rays from high power sources, dose-rates can be modulated based upon accelerator power and the attenuation of the X-ray by the distance of the material from the X-ray target. Dose and dose-rate dependence has been found to be of consequence in several commercial applications which can employ the use of ionizing radiation. The combination of dose and dose-rate dependence of the polymerization and crosslinking of wood impregnants and of fiber composite matrix materials can yield more economically viable results which have promising commercial potential. Monomer and oligomer structure also play an important role in attaining these desirable results. The influence of morphology is shown on the radiation response of olefin polymers, such as ethylene, propylene and isobutylene polymers and their copolymers. Both controlled morphology and controlled dose-rate have commercial consequences. These are also impacted both by the adroit selection of materials and through the possible use of X-ray processing

Use of oxygen dosing to prevent flow accelerated corrosion in British Energy's Advanced Gas-Cooled Reactors

International Nuclear Information System (INIS)

Quirk, G.P.; Woolsey, I.S.; Rudge, A.

2010-01-01

Flow accelerated corrosion (FAC) was recognized as major threat to the carbon steel feed and economizer tubing of the once-through boilers of the UK's Advanced Gas-cooled Reactors (AGRs) following the observation of FAC damage of the boiler inlet orifice assemblies at two plants in 1977, and subsequent review of the likelihood of further damage elsewhere within the boilers of all AGRs. In most cases, replacement of susceptible tubing was not feasible; due to the inaccessibility of the boiler components within the reactor concrete pressure vessel. Preventing further FAC damage within the boilers therefore had to rely largely on changes to the boiler feedwater chemistry. Following extensive research programs carried out in the late 1970s and early 1980s two main feedwater chemistry regimes were adopted to suppress FAC in different AGRs. The four units found to be at greatest risk of FAC damage adopted an oxygen dosed All Volatile Treatment (AVT) regime during commissioning, while four other units retained the original deoxygenated ammonia dosed AVT regime, but with an increased feedwater pH. The deoxygenated ammonia dosed chemistry regime was also adopted in four AGR units subsequently built, which used 1%Cr0.5%Mo feed and economizer tubing in their once-through boilers. The oxygen dosed AVT chemistry regime adopted in four units having helical once-through boilers has proved highly effective in preventing FAC, with no evidence of damage after around 150,000 hours of operation. However, FAC damage was eventually found in some of the other units operating with a deoxygenated feedwater chemistry regime, in spite of having adopted an elevated feedwater pH. These units have now successfully converted to an oxygen dosed AVT feedwater chemistry regime to prevent further FAC damage, with the result that all 14 AGR reactors now operate with variants of the original oxygen dosed feedwater chemistry regime developed during the 1980s. The paper outlines the development of

A convolution-superposition dose calculation engine for GPUs

Energy Technology Data Exchange (ETDEWEB)

Hissoiny, Sami; Ozell, Benoit; Despres, Philippe [Departement de genie informatique et genie logiciel, Ecole polytechnique de Montreal, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Departement de radio-oncologie, CRCHUM-Centre hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 (Canada)

2010-03-15

Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.

Control room envelope unfiltered air inleakage test protocols

International Nuclear Information System (INIS)

Lagus, P.L.; Grot, R.A.

1997-01-01

In 1983, the Advisory Committee on Reactor Safeguards (ACRS) recommended that the US NRC develop a control room HVAC performance testing protocol. To date no such protocol has been forthcoming. Beginning in mid-1994, an effort was funded by NRC under a Small Business Innovation Research (SBIR) grant to develop several simplified test protocols based on the principles of tracer gas testing in order to measure the total unfiltered inleakage entering a CRE during emergency mode operation of the control room ventilation system. These would allow accurate assessment of unfiltered air inleakage as required in SRP 6.4. The continuing lack of a standard protocol is unfortunate since one of the significant parameters required to calculate operator dose is the amount of unfiltered air inleakage into the control room. Often it is assumed that, if the Control Room Envelope (CRE) is maintained at +1/8 in. w.g. differential pressure relative to the surroundings, no significant unfiltered inleakage can occur it is further assumed that inleakage due to door openings is the only source of unfiltered air. 23 refs., 13 figs., 2 tabs

Control room envelope unfiltered air inleakage test protocols

Energy Technology Data Exchange (ETDEWEB)

Lagus, P.L. [Lagus Applied Technology, San Diego, CA (United States); Grot, R.A. [Lagus Applied Technology, Olney, MD (United States)

1997-08-01

In 1983, the Advisory Committee on Reactor Safeguards (ACRS) recommended that the US NRC develop a control room HVAC performance testing protocol. To date no such protocol has been forthcoming. Beginning in mid-1994, an effort was funded by NRC under a Small Business Innovation Research (SBIR) grant to develop several simplified test protocols based on the principles of tracer gas testing in order to measure the total unfiltered inleakage entering a CRE during emergency mode operation of the control room ventilation system. These would allow accurate assessment of unfiltered air inleakage as required in SRP 6.4. The continuing lack of a standard protocol is unfortunate since one of the significant parameters required to calculate operator dose is the amount of unfiltered air inleakage into the control room. Often it is assumed that, if the Control Room Envelope (CRE) is maintained at +1/8 in. w.g. differential pressure relative to the surroundings, no significant unfiltered inleakage can occur it is further assumed that inleakage due to door openings is the only source of unfiltered air. 23 refs., 13 figs., 2 tabs.

Utilization of electron beam accelerators for polymer processing

International Nuclear Information System (INIS)

Sarma, K.S.S.

2013-01-01

During the last decade, electron beam processing has been amply demonstrated to the Indian cable industry by BARC using 2 MeV/20 kW electron beam (EB) accelerator (ILU-6 EBA facility) located at BARC-BRIT complex, Vashi. The electron beam accelerator is a machine producing high energy electrons which are made to impinge on the materials for inducing physical, chemical and biological modifications. The process is carried out at room temperature and in ambient atmospheric conditions. Lately, quite a few numbers of accelerators have been installed by the private cable industry and carrying out cross-linking of cable insulations for high performance viz. high temperature stability, good flame retardancy, lesser solvent-swelling, thinner insulations etc. The indigenously made accelerators at EB centre, particularly the 3 MeV/30 kW accelerator will be of much help for Indian industry for polymer processing as the market is poised to grow by adapting the technology

Studying the induced radioactivity of a varian clinac 2100C/D accelerator

International Nuclear Information System (INIS)

Lu Feng; Li Hailiang; Deng Daping; Shang Yunying; Jing Zhongjun

2008-01-01

Objective: To Study the influences of dose, time, distance and irradiation mode on induced radioactivity by measuring a Varian Clinac 2100C/D accelerator. Methods: The induced radioactivity was measured in different dose, time, distance and irradiation mode by using of 450P model dosemeter. The results was analysed. Results: The induced radioactivity is direct ratio with dose, inverse ratio with time and distance. In different irradiation mode, the induced radioactivity is different. Conclusion: The induced radioactivity level of accelerator is related with dose, time, distance and irradiation mode. (authors)

Damage situation by the Great East Japan Earthquake and post-quake reconstruction project of the Tandem Accelerator Facility at the University of Tsukuba

International Nuclear Information System (INIS)

Sasa, Kimikazu

2012-01-01

The 12UD Pelletron tandem accelerator at the University of Tsukuba suffered serious damage from the Great East Japan Earthquake on 11 March 2011. On the day, the 12UD Pelletron tandem accelerator was in operation at 8 MV. The electricity supply went out during the earthquake. Fortunately, there were no causalties by the earthquake in the facility. However, all high voltage accelerating columns fell down in the accelerator tank. We decided to shut down the 12UD Pelletron tandem accelerator. At present, we have a plan to install a new middle-sized tandem accelerator instead of the broken 12UD Pelletron tandem accelerator at the 2nd target room connecting the beam line to existing facilities at the 1st target room. The construction of the new accelerator system will be completed by spring 2014. (author)

Results of a Conservative Dose Plan Linear Accelerator-Based Stereotactic Radiosurgery for Pediatric Intracranial Arteriovenous Malformations.

Science.gov (United States)

Rajshekhar, Vedantam; Moorthy, Ranjith K; Jeyaseelan, Visalakshi; John, Subhashini; Rangad, Faith; Viswanathan, P N; Ravindran, Paul; Singh, Rabiraja

2016-11-01

To evaluate the obliteration rate and clinical outcome following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) in pediatric patients (age ≤18 years). Factors associated with the obliteration rate and neurologic complications were studied retrospectively in pediatric patients who underwent LINAC-based SRS for AVM between June 1995 and May 2014. The study cohort comprised 36 males and 33 females, with a median age at the time of SRS of 14 years (range, 7-18 years). The mean AVM volume was 8.5 ± 8.7 cc (range, 0.6-41.8 cc). The median marginal dose of radiation delivered was 15 Gy (range, 9-20 Gy). Magnetic resonance imaging (MRI) demonstrated complete obliteration of the AVM in 44 of the 69 patients (63.8%), at a mean follow up of 27.5 months (range, 12-90 months). On subgroup analysis, 41 of the 53 AVMs of ≤14 cc in volume (77.3%) were obliterated. AVMs with a modified AVM radiosurgery score <1 had significantly shorter obliteration times from the time of SRS (P = .006). On multivariate analysis, the mean marginal dose of radiation delivered to the AVM was the sole significant predictor of obliteration (odds ratio, 1.6; 95% confidence interval, 1 to 2.4). A modest median marginal dose of 15 Gy (16 Gy in the obliterated AVM group vs. 12 Gy in the nonobliterated group) resulted in an obliteration rate of 66.7% after LINAC-based SRS for intracranial AVM, with low rate. Copyright © 2016 Elsevier Inc. All rights reserved.

Work plan for the Hanford Environmental Dose Reconstruction Project

Energy Technology Data Exchange (ETDEWEB)

1989-12-01

The primary objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that populations could have received from nuclear operations at the Hanford Site since 1944, with descriptions of uncertainties inherent in such estimates. The secondary objective is to make project records--information that HEDR staff members used to estimate radiation doses--available to the public. Preliminary dose estimates for a limited geographic area and time period, certain radionuclides, and certain populations are planned to be available in 1990; complete results are planned to be reported in 1993. Project reports and references used in the reports are available to the public in the DOE Public Reading Room in Richland, Washington. Project progress is documented in monthly reports, which are also available to the public in the DOE Public Reading Room.

Vacuum system for Advanced Test Accelerator

International Nuclear Information System (INIS)

Denhoy, B.S.

1981-01-01

The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10 -6 torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing

Vacuum system for Advanced Test Accelerator

Energy Technology Data Exchange (ETDEWEB)

Denhoy, B.S.

1981-09-03

The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10/sup -6/ torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing.

A shielding design for an accelerator-based neutron source for boron neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Hawk, A.E.; Blue, T.E. E-mail: blue.1@osu.edu; Woollard, J.E

2004-11-01

Research in boron neutron capture therapy (BNCT) at The Ohio State University Nuclear Engineering Department has been primarily focused on delivering a high quality neutron field for use in BNCT using an accelerator-based neutron source (ABNS). An ABNS for BNCT is composed of a proton accelerator, a high-energy beam transport system, a {sup 7}Li target, a target heat removal system (HRS), a moderator assembly, and a treatment room. The intent of this paper is to demonstrate the advantages of a shielded moderator assembly design, in terms of material requirements necessary to adequately protect radiation personnel located outside a treatment room for BNCT, over an unshielded moderator assembly design.

Monitoring proton radiation therapy with in-room PET imaging

International Nuclear Information System (INIS)

Zhu Xuping; Ouyang Jinsong; El Fakhri, Georges; Espana, Samuel; Daartz, Juliane; Liebsch, Norbert; Paganetti, Harald; Bortfeld, Thomas R

2011-01-01

We used a mobile positron emission tomography (PET) scanner positioned within the proton therapy treatment room to study the feasibility of proton range verification with an in-room, stand-alone PET system, and compared with off-line equivalent studies. Two subjects with adenoid cystic carcinoma were enrolled into a pilot study in which in-room PET scans were acquired in list-mode after a routine fractionated treatment session. The list-mode PET data were reconstructed with different time schemes to generate in-room short, in-room long and off-line equivalent (by skipping coincidences from the first 15 min during the list-mode reconstruction) PET images for comparison in activity distribution patterns. A phantom study was followed to evaluate the accuracy of range verification for different reconstruction time schemes quantitatively. The in-room PET has a higher sensitivity compared to the off-line modality so that the PET acquisition time can be greatly reduced from 30 to 15 O component and lower biological washout. For soft tissue-equivalent material, the distal fall-off edge of an in-room short acquisition is deeper compared to an off-line equivalent scan, indicating a better coverage of the high-dose end of the beam. In-room PET is a promising low cost, high sensitivity modality for the in vivo verification of proton therapy. Better accuracy in Monte Carlo predictions, especially for biological decay modeling, is necessary.

Estimation of Electron Dose Delivered by a 0.4 MeV Accelerator from Bremsstrahlung Dose Measurements

DEFF Research Database (Denmark)

Karadjov, A. G.; Hansen, Jørgen-Walther

1980-01-01

Determination of a 0.4 MeV electron dose from a bremsstrahlung dose measurement using a converter-detector system is considered. The detector used is a Frickle dosimeter, and the converters are aluminum, copper and lead foils. Optimal converter thickness is ascertained experimentally for each mat...... materials within a Z-range of 13–82. A linear relation is found between bremsstrahlung dose and electron dose ranging from 2 to 20 Mrad. Finally the effect of converter area on detector response is studied....

Low energy accelerators for research and applications

International Nuclear Information System (INIS)

Bhandari, R.K.

2013-01-01

Charged particle accelerators are instruments for producing a variety of radiations under controlled conditions for basic and applied research as well as applications. They have helped enormously to study the matter, atoms, nuclei, sub-nuclear particles and their constituents, forces involved in the related phenomena etc. No other man-made instrument has been so effective in such studies as the accelerator. The large accelerator constructed so far is the Large Hadron Collider (LHC) housed in a tunnel of 27 km circumference, while a small accelerator can fit inside a room. Small accelerators accelerate charged particles such as electrons, protons, deuterons, alphas and, in general ions to low energy, generally, below several MeV. These particle beams are used for studies in nuclear astrophysics, atomic physics, material science, surface physics, bio sciences etc. They are used for ion beam analysis such as RBS, PIXE, NRA, AMS, CPAA etc. More importantly, the ion beams have important industrial applications like ion implantation, surface modification, isotope production etc. while electron beams are used for material processing, material modification, sterilization, food preservation, non destructive testing etc. In this talk, role of low energy accelerators in research and industry as well as medicine will be discussed. (author)

Patient radiation doses from enteroclysis examinations

International Nuclear Information System (INIS)

Hart, D.; Wall, B.F.; Haggett, P.J.; Boardman, P.; Nolan, D.J.

1994-01-01

Data relating to patient dose have been acquired for enteroclysis examinations (small bowel enemas) performed at the John Radcliffe Hospital, Oxford, on 23 adult patients. Dose-area products, fluoroscopy times and the number of radiographs taken are used to compare the examination procedure at the Hospital with enteroclysis and barium follow-throughs performed elsewhere. The mean dose-area product for the 23 examinations was 6.8 Gy cm 2 and the mean effective dose was estimated to be 1.5 mSv. These doses are intermediate between those arising from barium meals and barium enemas performed in the same room. (author)

THE USE OF DISPERSION STRENGTHENED COPPER IN ACCELERATOR DESIGNS

International Nuclear Information System (INIS)

VALDIVIEZ, R.; SCHRAGE, D.

2000-01-01

Dispersion strengthened copper, known by the trade name GLIDCOP(reg sign), has found various applications in accelerator designs. Glidcop has material properties similar to OFE copper, such as thermal and electrical conductivity. Unlike OFE, however, Glidcop has yield and ultimate strengths equivalent to those of mild-carbon steel, making it a good structural material. This paper covers some accelerator components fabricated with Glidcop, material properties measured from room to brazing temperatures, and a furnace-brazing process that has produced good, consistent results with Glidcop

X radiations dosimetry in pulmonary radiographs: study of a non standard room

International Nuclear Information System (INIS)

Bied, J.C.; Philippon, B.

1998-01-01

A radiograph room can present a default of radiation protection. But it is possible that the radiation protection is here only to mask a protection of an other type. For the case of a lungs type radiograph room, the monitoring does not reveal any problem of radiation protection. These results do not bring to the fore any high radiations doses. But they are an illustration of operators positions, and these ones should be better protected at the extremity of the room, that should allow a correct vision of lungs radiographs and a more important limitation of irradiation. (N.C.)

A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

International Nuclear Information System (INIS)

Saenz, Daniel L.; Paliwal, Bhudatt R.; Bayouth, John E.

2014-01-01

ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 ( 60 Co) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving 60 Co ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system. (author)

A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans.

Science.gov (United States)

Saenz, Daniel L; Paliwal, Bhudatt R; Bayouth, John E

2014-04-01

ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60) with 0.35 Tesla magnetic resonance imaging (MRI) allows for magnetic resonance (MR)-guided intensity-modulated radiation therapy (IMRT) delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI), conformity index (CI), and volume receiving ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

Control rooms and man-machine interface in nuclear power plants

International Nuclear Information System (INIS)

1990-08-01

The importance of man-machine interface for ensuring safe and reliable operation of nuclear power plants has always been recognized. Since the early 1970's, the concepts of operator support and human factors have been increasingly used to better define the role of control rooms. In the late 1970's, the lessons learned from experience considerably accelerated the development of recommendations and regulatory requirements governing the resources and data available to operators in nuclear power plant control rooms, and specified the expertise required to assist them in case of need. This document summarizes the steps which have been taken and are being planned around the world to improve the man-machine interface for safe and economic power generation. It intends to present to the reader useful examples on some selected control room design and man-machine interface practices for operation and surveillance of nuclear power plants. 53 refs, 94 figs, 27 tabs

PET/CT-guided Interventions: Personnel Radiation Dose

International Nuclear Information System (INIS)

Ryan, E. Ronan; Thornton, Raymond; Sofocleous, Constantinos T.; Erinjeri, Joseph P.; Hsu, Meier; Quinn, Brian; Dauer, Lawrence T.; Solomon, Stephen B.

2013-01-01

PurposeTo quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.MethodsIn this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).ResultsThe median effective dose was 0.02 (range 0–0.13) mSv for the primary operator, 0.01 (range 0–0.05) mSv for the nurse anesthetist, and 0.02 (range 0–0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0–0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).ConclusionThe operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient

Heavy-ion-linac post-accelerators

International Nuclear Information System (INIS)

Bollinger, L.M.

1979-01-01

The main features of the tandem-linac system for heavy-ion acceleration are reviewed and illustrated in terms of the technology and performance of the superconducting heavy-ion energy booster at Argonne. This technology is compared briefly with the corresponding technologies of the superconducting linac at Stony Brook and the room-temperature linac at Heidelberg. The performance possibilities for the near-term future are illustrated in terms of the proposed extension of the Argonne booster to form ATLAS

Developing a clinical proton accelerator facility: Consortium-assisted technology transfer

International Nuclear Information System (INIS)

Slater, J.M.; Miller, D.W.; Slater, J.W.

1991-01-01

A hospital-based proton accelerator facility has emerged from the efforts of a consortium of physicists, engineers and physicians from several high-energy physics laboratories, industries and universities, working together to develop the requirements and conceptual design for a clinical program. A variable-energy medical synchrotron for accelerating protons to a prescribed energy, intensity and beam quality, has been placed in a hospital setting at Loma Linda University Medical Center for treating patients with localized cancer. Treatments began in October 1990. Scientists from Fermi National Accelerator Laboratory; Harvard Cyclotron Laboratory; Lawrence Berkeley Laboratories; the Paul Scherrer Institute; Uppsala, Sweden; Argonne, Brookhaven and Los Alamos National Laboratories; and Loma Linda University, all cooperated to produce the conceptual design. Loma Linda University contracted with Fermi National Accelerator Laboratory to design and build a 250 MeV synchrotron and beam transport system, the latter to guide protons into four treatment rooms. Lawrence Berkeley Laboratories consulted with Loma Linda University on the design of the beam delivery system (nozzle). A gantry concept devised by scientists at Harvard Cyclotron Laboratory, was adapted and fabricated by Science Applications International Corporation. The control and safety systems were designed and developed by Loma Linda University Radiation Research Laboratory. Presently, the synchrotron, beam transport system and treatment room hardware have been installed and tested and are operating satisfactorily

Acceleration of skin wound healing by low-dose indirect ionizing radiation in male rats.

Science.gov (United States)

Jabbari, Nasrollah; Farjah, Gholam Hossein; Ghadimi, Behnam; Zanjani, Hajar; Heshmatian, Behnam

2017-08-01

A recent hypothesis has revealed that low-dose irradiation (LDI) with ionizing radiation might have a promoting effect on fracture healing. The aim of this study was to investigate the influence of direct (electron beam) and indirect (gamma-ray) low-dose ionizing irradiations on the wound healing process in male rats. In 72 male rats, a full-thickness wound was incised. The animals were randomly assigned to three groups, each with 24 rats. The first two groups were named IG-I and IG-II and respectively exposed to electron and gamma-radiations (75 cGy) immediately after the surgical procedure. The third group was considered as the control (CG) and remained untreated. Skin biopsies from the subgroups were collected on days 3, 7, 15, and 21 after the operation and evaluated using histological and biomechanical methods. Data were analyzed by one-way ANOVA, followed by Tukey's post hoc test using SPSS 20 software. Histological studies of tissues showed that the mean number of fibroblasts, macrophages, blood vessel sections, and neutrophils on the third and seventh days after the surgery in the gamma-treated group was higher than that in both other groups. In contrast, on day 21, the mean number of mentioned cells in the gamma-treated group was lower than in the other two groups. In addition, the mean maximum stress value was significantly greater in the gamma-treated group. Results of this study showed that gamma-ray irradiation is effective in the acceleration of wound healing. Copyright © 2017. Published by Elsevier Taiwan.

Acceleration of skin wound healing by low-dose indirect ionizing radiation in male rats

Directory of Open Access Journals (Sweden)

Nasrollah Jabbari

2017-08-01

Full Text Available A recent hypothesis has revealed that low-dose irradiation (LDI with ionizing radiation might have a promoting effect on fracture healing. The aim of this study was to investigate the influence of direct (electron beam and indirect (gamma-ray low-dose ionizing irradiations on the wound healing process in male rats. In 72 male rats, a full-thickness wound was incised. The animals were randomly assigned to three groups, each with 24 rats. The first two groups were named IG–I and IG–II and respectively exposed to electron and gamma-radiations (75 cGy immediately after the surgical procedure. The third group was considered as the control (CG and remained untreated. Skin biopsies from the subgroups were collected on days 3, 7, 15, and 21 after the operation and evaluated using histological and biomechanical methods. Data were analyzed by one-way ANOVA, followed by Tukey's post hoc test using SPSS 20 software. Histological studies of tissues showed that the mean number of fibroblasts, macrophages, blood vessel sections, and neutrophils on the third and seventh days after the surgery in the gamma-treated group was higher than that in both other groups. In contrast, on day 21, the mean number of mentioned cells in the gamma-treated group was lower than in the other two groups. In addition, the mean maximum stress value was significantly greater in the gamma-treated group. Results of this study showed that gamma-ray irradiation is effective in the acceleration of wound healing.

Spatial dependence and origin of the ambient dose due to neutron activation processes in linear accelerators; Dependencia espacial y origen de la dosis ambiental debeda a procesos de activacion neutronica en aceleradores lineales

Energy Technology Data Exchange (ETDEWEB)

Ruiz Egea, E.; Sanchez Carrascal, M.; Torres Pozas, S.; Monja Ray, P. de la; Perez Molina, J. L.; Madan Rodriguez, C.; Luque Japon, L.; Morera Molina, A.; Hernandez Perez, A.; Barquero Bravo, Y.; Morengo Pedagna, I.; Oliva Gordillo, M. C.; Martin Olivar, R.

2011-07-01

In order to try to determine the high dose in the bunker of a Linear Accelerator clinical use trying to measure the spatial dependence of the same from the isocenter to gateway to the board cheeking to establish the origin of it. This dose measurements performed with an ionization chamber at different locations inside the bunker after an irradiation of 400 Monitor Units verifying the dose rate per minute for an hour, and accumulating the dose received during that period of time.

Organ and effective dose rate coefficients for submersion exposure in occupational settings

International Nuclear Information System (INIS)

Veinot, K.G.; Dewji, S.A.; Hiller, M.M.; Eckerman, K.F.; Easterly, C.E.

2017-01-01

External dose coefficients for environmental exposure scenarios are often computed using assumption on infinite or semi-infinite radiation sources. For example, in the case of a person standing on contaminated ground, the source is assumed to be distributed at a given depth (or between various depths) and extending outwards to an essentially infinite distance. In the case of exposure to contaminated air, the person is modeled as standing within a cloud of infinite, or semi-infinite, source distribution. However, these scenarios do not mimic common workplace environments where scatter off walls and ceilings may significantly alter the energy spectrum and dose coefficients. In this paper, dose rate coefficients were calculated using the International Commission on Radiological Protection (ICRP) reference voxel phantoms positioned in rooms of three sizes representing an office, laboratory, and warehouse. For each room size calculations using the reference phantoms were performed for photons, electrons, and positrons as the source particles to derive mono-energetic dose rate coefficients. Since the voxel phantoms lack the resolution to perform dose calculations at the sensitive depth for the skin, a mathematical phantom was developed and calculations were performed in each room size with the three source particle types. Coefficients for the noble gas radionuclides of ICRP Publication 107 (e.g., Ne, Ar, Kr, Xe, and Rn) were generated by folding the corresponding photon, electron, and positron emissions over the mono-energetic dose rate coefficients. Results indicate that the smaller room sizes have a significant impact on the dose rate per unit air concentration compared to the semi-infinite cloud case. For example, for Kr-85 the warehouse dose rate coefficient is 7% higher than the office dose rate coefficient while it is 71% higher for Xe-133. (orig.)

Organ and effective dose rate coefficients for submersion exposure in occupational settings

Energy Technology Data Exchange (ETDEWEB)

Veinot, K.G. [Easterly Scientific, Knoxville, TN (United States); Y-12 National Security Complex, Oak Ridge, TN (United States); Dewji, S.A.; Hiller, M.M. [Center for Radiation Protection Knowledge, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Eckerman, K.F.; Easterly, C.E. [Easterly Scientific, Knoxville, TN (United States)

2017-11-15

External dose coefficients for environmental exposure scenarios are often computed using assumption on infinite or semi-infinite radiation sources. For example, in the case of a person standing on contaminated ground, the source is assumed to be distributed at a given depth (or between various depths) and extending outwards to an essentially infinite distance. In the case of exposure to contaminated air, the person is modeled as standing within a cloud of infinite, or semi-infinite, source distribution. However, these scenarios do not mimic common workplace environments where scatter off walls and ceilings may significantly alter the energy spectrum and dose coefficients. In this paper, dose rate coefficients were calculated using the International Commission on Radiological Protection (ICRP) reference voxel phantoms positioned in rooms of three sizes representing an office, laboratory, and warehouse. For each room size calculations using the reference phantoms were performed for photons, electrons, and positrons as the source particles to derive mono-energetic dose rate coefficients. Since the voxel phantoms lack the resolution to perform dose calculations at the sensitive depth for the skin, a mathematical phantom was developed and calculations were performed in each room size with the three source particle types. Coefficients for the noble gas radionuclides of ICRP Publication 107 (e.g., Ne, Ar, Kr, Xe, and Rn) were generated by folding the corresponding photon, electron, and positron emissions over the mono-energetic dose rate coefficients. Results indicate that the smaller room sizes have a significant impact on the dose rate per unit air concentration compared to the semi-infinite cloud case. For example, for Kr-85 the warehouse dose rate coefficient is 7% higher than the office dose rate coefficient while it is 71% higher for Xe-133. (orig.)

Mathematical simulation of biologically equivalent doses for LDR-HDR

International Nuclear Information System (INIS)

Slosarek, K.; Zajusz, A.

1996-01-01

Based on the LQ model examples of biologically equivalent doses LDR, HDR and external beams were calculated. The biologically equivalent doses for LDR were calculated by appending to the LQ model the corrector for the time of repair of radiation sublethal damages. For radiation continuously delivered at a low dose rate the influence of sublethal damage repair time changes on biologically equivalent doses were analysed. For fractionated treatment with high dose rate the biologically equivalent doses were calculated by adding to the LQ model the formula of accelerated repopulation. For total biologically equivalent dose calculation for combine LDR-HDR-Tele irradiation examples are presented with the use of different parameters of the time of repair of sublethal damages and accelerated repopulation. The calculations performed show, that the same biologically equivalent doses can be obtained for different parameters of cell kinetics changes during radiation treatment. It also shows, that during biologically equivalent dose calculations for different radiotherapy schedules, ignorance of cell kinetics parameters can lead to relevant errors

Quantification and reduction of peripheral dose from leakage radiation on Siemens Primus accelerators in electron therapy mode.

Science.gov (United States)

Yeboah, Collins; Karotki, Alex; Hunt, Dylan; Holly, Rick

2010-06-15

In this work, leakage radiation from EA200 series electron applicators on Siemens Primus accelerators is quantified, and its penetration ability in water and/or the shielding material Xenolite-NL established. Initially, measurement of leakage from 10 x 10 - 25 x 25 cm2 applicators was performed as a function of height along applicator and of lateral distance from applicator body. Relative to central-axis ionization maximum in solid water, the maximum leakage in air observed with a cylindrical ion chamber with 1 cm solid water buildup cap at a lateral distance of 2 cm from the front and right sidewalls of applicators were 17% and 14%, respectively; these maxima were recorded for 18 MeV electron beams and applicator sizes of >or=20 x 20 cm2. In the patient plane, the applicator leakage gave rise to a broad peripheral dose off-axis distance peak that shifted closer to the field edge as the electron energy increases. The maximum peripheral dose from normally incident primary electron beams at a depth of 1 cm in a water phantom was observed to be equal to 5% of the central-axis dose maximum and as high as 9% for obliquely incident beams with angles of obliquity dose curves showed that the "practical range" of the leakage electrons in water varies from approximately 1.4 to 5.7 cm as the primary electron beam energy is raised from 6 to 18 MeV. Next, transmission measurements of leakage radiation through the shielding material Xenolite-NL showed a 4 mm thick sheet of this material is required to attenuate the leakage from 9 MeV beams by two-thirds, and that for every additional 3 MeV increase in the primary electron beam energy, an additional Xenolite-NL thickness of roughly 2 mm is needed to achieve the aforementioned attenuation level. Finally, attachment of a 1 mm thick sheet of lead to the outer surface of applicator sidewalls resulted in a reduction of the peripheral dose by up to 80% and 74% for 9 and 18MeV beams, respectively. This sidewall modification had an

A dose homogeneity and conformity evaluation between ViewRay and pinnacle-based linear accelerator IMRT treatment plans

Directory of Open Access Journals (Sweden)

Daniel L Saenz

2014-01-01

Full Text Available ViewRay, a novel technology providing soft-tissue imaging during radiotherapy is investigated for treatment planning capabilities assessing treatment plan dose homogeneity and conformity compared with linear accelerator plans. ViewRay offers both adaptive radiotherapy and image guidance. The combination of cobalt-60 (Co-60 with 0.35 Tesla magnetic resonance imaging (MRI allows for magnetic resonance (MR-guided intensity-modulated radiation therapy (IMRT delivery with multiple beams. This study investigated head and neck, lung, and prostate treatment plans to understand what is possible on ViewRay to narrow focus toward sites with optimal dosimetry. The goal is not to provide a rigorous assessment of planning capabilities, but rather a first order demonstration of ViewRay planning abilities. Images, structure sets, points, and dose from treatment plans created in Pinnacle for patients in our clinic were imported into ViewRay. The same objectives were used to assess plan quality and all critical structures were treated as similarly as possible. Homogeneity index (HI, conformity index (CI, and volume receiving <20% of prescription dose (DRx were calculated to assess the plans. The 95% confidence intervals were recorded for all measurements and presented with the associated bars in graphs. The homogeneity index (D5/D95 had a 1-5% inhomogeneity increase for head and neck, 3-8% for lung, and 4-16% for prostate. CI revealed a modest conformity increase for lung. The volume receiving 20% of the prescription dose increased 2-8% for head and neck and up to 4% for lung and prostate. Overall, for head and neck Co-60 ViewRay treatments planned with its Monte Carlo treatment planning software were comparable with 6 MV plans computed with convolution superposition algorithm on Pinnacle treatment planning system.

Application of shielding calculation of high-energy linear accelerators based on the NCRP-151 protocol

International Nuclear Information System (INIS)

Torres Pozas, S.; Monja Rey, P. de la; Sanchez Carrasca, M.; Yanez Lopez, D.; Macias Verde, D.; Martin Oliva, R.

2011-01-01

In recent years, the progress experienced in cancer treatment with ionizing radiation can deliver higher doses to smaller volumes and better shaped, making it necessary to take into account new aspects in the calculation of structural barriers. Furthermore, given that forecasts suggest that in the near future will install a large number of accelerators, or existing ones modified, we believe a useful tool to estimate the thickness of the structural barriers of treatment rooms. The shielding calculation methods are based on standard DIN 6847-2 and the recommendations given by the NCRP 151. In our experience we found only estimates originated from the DIN. Therefore, we considered interesting to develop an application that incorporates the formulation suggested by the NCRP, together with previous work based on the rules DIN allow us to establish a comparison between the results of both methods. (Author)

Control room unfiltered in-leakage limit analysis of design-basis LOCA for Lungmen ABWR plant

International Nuclear Information System (INIS)

Tsai Chihming; Chang Chinjang; Yuann Yngruey

2014-01-01

In USNRC's Generic Letter 2003-01, 'Control Room Habitability,' it requests utilities provide information to demonstrate that the control room at each of their respective facilities complies with the current licensing and design bases, and applicable regulatory requirements, and that suitable design, maintenance and testing control measures are in place for maintaining this compliance. In particular, each utility is required to perform the control room in-leakage test to demonstrate that the unfiltered in-leakage rate is within that assumed in the licensing analyses. It must be ensured that the control room envelope habitability, in terms of radiation dose, is maintained during normal operations as well as design basis accidents. In view of this, a dose analysis has been performed to establish the control room unfiltered in-leakage limit which can be used as an acceptance criterion for the in-leakage test. The analysis in this study is for Lungmen ABWR plant. The plant has twin units, with each unit having its own control room. The TID-4844 source terms and associated methodology are used. The USNRC RADTRAD v3.03 code is employed for the transport calculation of radioactive materials in different paths, including control room in-leakage path. The radiological criterion on protection of the operators specified in 10 CFR 50, Appendix A, General Design Criterion 19 is followed. It's demonstrated that the performance of Lungmen control room with 500 cfm unfiltered in-leakage air could meet the radiological habitability acceptance criteria in case of radiation hazards. (author)

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

Monitoring of dose rates and radiation flux density in working rooms

International Nuclear Information System (INIS)

Krajtor, S.N.

1980-01-01

The problems of determining the neutron field characteristics (dose equivalent rate and flux density) in relation to the environmental monitoring by radiation protection services. The measurement devices used for measuring dose equivalent rate and neutron flux density RUS-U8 multi-purpose scintillation radiometer and RUP-1 multi-purpose transportable radiometer as well as measurement technique are described. Recommendations are given for checking measuring devices calibration, registering measurement results [ru

Recent Developments in Hadron Therapy Accelerators

CERN Document Server

Klein, Hans-Udo

2005-01-01

In the last decade interest and investments in Hadron Therapy Systems have been steadily increasing resulting in a substantial number of projects currently under construction or entering detailed planning stage. Main routes are pure proton therapy systems and Carbon ion therapy systems which can also run on protons. While the basic accelerator concept for hadron therapy systems is well established there are many considerations on the type and layout of the particle delivery system including the accelerator, an energy selection system, either a fixed beam set up or a rotating gantry, the "nozzle" containing either a scattering or a scanning system, the patient positioner, and all associated control systems. The requirements for the accelerator include most stable beams to match the demand of modern fast scanning systems as well as fast switching between treatment rooms. Currently an ion/proton synchrotron, a pure proton synchrotron, a normalconducting proton cyclotron and a newly developed compact superconduct...

Accelerators for condensed matter research

International Nuclear Information System (INIS)

Williams, P.R.

1990-01-01

The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator.

Science.gov (United States)

Putha, Suman Kumar; Saxena, P U; Banerjee, S; Srinivas, Challapalli; Vadhiraja, B M; Ravichandran, Ramamoorthy; Joan, Mary; Pai, K Dinesh

2016-01-01

Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (S t ) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. S t s were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (D iso,TPS ), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (D iso,Transit ) from the measured S t s. A locally fabricated pelvic phantom validated the estimations of D iso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The D iso,Transit agreement with D iso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is -1.37% ±2.03% ( n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

THE CARE PROJECT - Coordinated Accelerator Research in Europe

CERN Multimedia

2003-01-01

A one-day presentation of the project will take place on Monday February 10th in the CERN Council Chamber. The meeting will start a 9am and is expected to end at 4:30pm. The meeting, which is open to the whole community, will present an initiative on accelerator R&D in Europe, supported by ECFA, with the aim to bid for European Union support through the Framework 6 scheme. This initiative is coordinated by a steering group (ESGARD - European Steering Group on Accelerator Research and Development), which has been set up to coordinate European efforts on accelerator R&D and the submission of such bids. The initial bids have to be submitted by April 15th. All those interested in accelerator R&D are welcome to attend. Presentation of the CARE project (Coordinated Accelerator Research in Europe) to be submitted within FP6 February 10th, at CERN in the council room Agenda Chair : C. Wyss 9:00 General presentation of FP6 and introduction of IA proposal (R. Aleksan) 9:45 Networking activities on e ...